ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • phosphorus  (73)
  • evolution  (68)
  • apoptosis  (52)
  • Springer  (193)
  • American Chemical Society
  • American Meteorological Society
  • 1995-1999  (193)
  • 1990-1994
  • 1955-1959
  • 1999  (193)
Collection
Keywords
Publisher
Years
  • 1995-1999  (193)
  • 1990-1994
  • 1955-1959
Year
  • 1
    facet.materialart.
    Unknown
    Die Erde im Visier - Geowissenschaften an der Schwelle zum 21. Jahrhundert (1999)
    Springer
    In:  Heidelberg, Springer, vol. 113, no. XVI:, pp. 1-14, (ISBN 1-56670-263-3)
    Details
    Publication Date: 1999
    Keywords: Handbook of geophysics ; Seismology ; Seismics (controlled source seismology) ; Early warning systems (earthquakes, volcanic eruptions, tsunamis etc.) ; Earthquake hazard ; KTB ; ICDP ; IOcean Drilling Program ; climate ; Antarctica ; Nuclear explosion ; Volcanology ; GeodesyY ; satellites ; remote ; sensing ; gas ; hydrates ; Geothermics ; Energy (of earthquakes) ; potable ; water ; waste ; soils ; evolution ; Geol. aspects ; geotechnics ; Engineering geophys. ; ores
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    BIBLIOGRAPHY SEISMOLOGY
  • 2
    Electronic Resource
    Electronic Resource
    Specificity of a Y-linked gene in the flea beetle Phyllotreta nemorum for defences in Barbarea vulgaris (1999)
    Springer
    Entomologia experimentalis et applicata 91 (1999), S. 359-368 
    Details
    ISSN: 1570-7458
    Keywords: Barbarea vulgaris ssp. arcuata ; Cruciferae ; Phyllotreta nemorum ; Chrysomelidae ; Alticinae ; flea beetle ; plant defence ; host plant range ; near-isogenic ; Y-linkage ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A Y-linked gene (R-gene) in the flea beetle Phyllotreta nemorum L. (Coleoptera: Chrysomelidae: Alticinae) confer the ability of larvae to survive on types of the plant Barbarea vulgaris R.Br. (Brassicaceae) which are immune to attack by susceptible conspecifics. Two near-isogenic flea beetle lines were developed. The YE-line contained the Y-linked R-gene, and male larvae from this line survived on B. vulgaris. The ST-line did not contain the gene and did not survive on the plant. The YE-line had been developed through 8–9 generations of backcrosses (YE-males with ST-females) and the two lines were considered to be isogenic except for genes located on the Y-chromosome. A single copy of the Y-linked gene is sufficient to transfer a susceptible genotype (ST) into a resistant genotype (YE) which is able to utilize a plant that is immune to attack by specimens without R-genes. The Y-linked gene had no effects on survival on other plant species tested. The gene did not have any effect on developmental times and weights of adult beetles reared on other plants than B. vulgaris. Developmental times of larvae with the Y-linked gene were longer on B. vulgaris than on normal host plants, R. sativus and S. arvensis, but the adults obtained the same size on these plant species. No trade-offs of the Y-linked gene were discovered. The results suggest that the occurrence of the Y-linked gene is a derived trait which has enabled the flea beetle to expand its host plant range. The evolution of a host shift to B. vulgaris seems not to be favoured by the presence of this single gene.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003622512914
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Specialist deterrent chemoreceptors enable Pieris caterpillars to discriminate between chemically different deterrents (1999)
    Springer
    Entomologia experimentalis et applicata 91 (1999), S. 29-35 
    Details
    ISSN: 1570-7458
    Keywords: chemoreception ; deterrents ; Pieris ; Brassicaceae ; cardenolides ; host-plant selection ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pieris butterflies (Lepidoptera: Pieridae) are specialist herbivores of cruciferous plants. They exploit glucosinolates, secondary plant metabolites chemotaxonomically characteristic for this plant family, as token stimuli. In addition to particular glucosinolates, some genera of the Cruciferae contain cardenolides, steroidal allelochemicals that act as potent feeding and oviposition deterrents to several Pieris species. We investigated the sensory mechanisms by which these compounds are perceived in larvae. Pieris caterpillars and many other lepidopterous species are endowed with so-called generalist deterrent receptors, that respond to a broad spectrum of secondary plant substances. In Pieris caterpillars we found a second type of deterrent chemoreceptor in maxillary styloconic taste sensilla. This neuron is very sensitive to cardenolides (threshold 0.1–0.3 μM). The generalist deterrent receptor also responds to these substances but its threshold lies at 50–100× higher concentrations. In behavioural preference experiments Pieris brassicae L. caterpillars preferred cardenolide-treated cabbage leaf discs when confronted with a choice between them and a deterrent substance that does not occur in the Brassicaceae. The cardenolides acted as potent deterrents when offered against untreated cabbage leaf discs. This demonstrates that the balance of activity elicited in the two types of deterrent chemoreceptors determines the behavioural decision.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003645222599
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    On the Adaptive Value of Some Mate Selection Strategies (1999)
    Springer
    Acta biotheoretica 47 (1999), S. 29-40 
    Details
    ISSN: 1572-8358
    Keywords: Sexual selection ; mate selection ; gamete selection ; evolution ; ploidy ; asssortative mating
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Results of an agent-based computer simulation of the evolution of diploid sexual organisms showed that several mate selection strategies confer much higher average fitness to the simulated populations, and higher evolutionary stability to the alleles coding for these strategies, than random mating. Strategies which select for 'good genes' were very successful, and so were strategies based on assortative mating. The results support the hypothesis that mating is not likely to be random in nature and that the most successful mate selection strategies are those based on assortative mating or on advantageous genes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1002022126388
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Ni–Zn–P alloy deposition from sulfate bath: inhibitory effect of zinc (1999)
    Springer
    Journal of applied electrochemistry 29 (1999), S. 1171-1176 
    Details
    ISSN: 1572-8838
    Keywords: alloys ; cyclic voltammetry ; electrodeposition ; electroless deposition ; nickel ; phosphorus ; zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Electroless Ni–Zn–P alloy deposition from a sulphate bath, containing sodium hypophosphite as reducer, was investigated. To increase the plating rate, the deposition parameters were optimized. The effect of process parameters (T, pH and [Zn2+]) on the plating rate and deposit composition was examined and it was found that the presence of zinc in the bath has an inhibitory effect on the alloy deposition. As a consequence, the percentage of zinc in the electroless Ni–Zn–P alloys never reaches high values. Using cyclic voltammetry the electrodeposition mechanism of Ni–Zn–P alloys was investigated. It was observed that the zinc deposition inhibits the nickel discharge and, as a consequence, its catalytic activity on hypophosphite oxidation. It was also found that increase in temperature or pH leads to the deposition of nickel rich alloys.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003426904395
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Microstructural characterization and corrosion resistance of Ni–Zn–P alloys electrolessly deposited from a sulphate bath (1999)
    Springer
    Journal of applied electrochemistry 29 (1999), S. 637-645 
    Details
    ISSN: 1572-8838
    Keywords: alloys ; electroless ; microstructure ; morphology ; nickel ; phosphorus ; zinc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Electroless Ni–Zn–P alloy coatings were obtained on an iron substrate from a sulfate bath at various pH values. The effects of changes in bath pH on alloy composition, morphology, microstructure and corrosion resistance were studied. Scanning electron microscopy was performed to observe the morphological change of the deposits with bath pH. Coating crystallinity was investigated by grazing incidence asymmetric Bragg X-ray diffraction and transmission electron microscopy. A transition from an amorphous to polycrystalline structure was observed on increasing the bath alkalinity, and thus decreasing the phosphorus content of the alloys. A single crystalline phase corresponding to face-centred-cubic nickel was identified in the alloys obtained from a strong alkaline solution. An increase in zinc percentage up to 23% in the deposits does not change the f.c.c. nickel crystalline structure. Corrosion potential and polarization resistance measurements indicated that the corrosion resistance of electroless Ni–Zn–P alloys depends strongly on the microstructure and chemical composition. The deposits obtained at pH 9.0–9.5 and with 11.4–12.5% zinc and 11.8–11.2% phosphorous exhibited the best corrosion resistance.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026441403282
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Apoptosis and p53 gene expression in male reproductive tissues of cadmium exposed rats (1999)
    Springer
    BioMetals 12 (1999), S. 131-139 
    Details
    ISSN: 1572-8773
    Keywords: cadmium ; apoptosis ; RT-PCR ; p53 gene expression ; testes ; rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Reverse transcription (RT) PCR technique was used to investigate the mechanism of apoptosis induced by Cd and the change of its related genes in testes and prostate of rats. Adult male rats were given a single (s.c.) injection of CdC l2 0, 2.5, 5.0, 10 μmol/kg. 48 h and 72 h after administration of Cd, animals were sacrificed. The results indicated that Cd can induce apoptosis in testes via p53-independent pathway. No apoptosis occurred in prostate in any of the Cd-exposed groups. There was a clearly negative relationship in testes between p53 gene expression and Cd exposure and this dose-response relationship was observed both at 48 h and 72 h. There was a very small increase of this gene expression in the dorsolateral lobe of the prostate in Cd exposed groups. The other apoptosis related gene, bcl-x, was not detectable in either control or Cd-exposed group in testes and dorsal prostate. Although the MT-I gene was expressed in testes or dorsal prostate both in control and exposed groups, no overexpression of MT-I gene was found after administration of Cd . The expression of MT-I in the ventral prostate was not detected in the control group, but a weak expression was found after Cd exposure. Since p53 is a tumo r suppressor gene which can inhibit tumorigenesis, the consequence of a Cd-induced decrease of p53 in testes may have a relation to the known risk of Cd tumorigenesis in this tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009273711068
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Syntax as an Emergent Characteristic of the Evolution of Semantic Complexity (1999)
    Springer
    Minds and machines 9 (1999), S. 309-346 
    Details
    ISSN: 1572-8641
    Keywords: language ; grammar ; syntax ; semantics ; evolution ; emergence ; brain size
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Philosophy
    Notes: Abstract It is commonly argued that the rules of language, as distinct from its semantic features, are the characteristics which most clearly distinguish language from the communication systems of other species. A number of linguists (e.g., Chomsky 1972, 1980; Pinker 1994) have suggested that the universal features of grammar (UG) are unique human adaptations showing no evolutionary continuities with any other species. However, recent summaries of the substantive features of UG are quite remarkable in the very general nature of the features proposed. While the syntax of any given language can be quite complex, the specific rules vary so much between languages that the truly universal (i.e. innate) aspects of grammar are not complex at all. In fact, these features most closely resemble a set of general descriptions of our richly complex semantic cognition, and not a list of specific rules. General principles of the evolutionary process suggest that syntax is more properly understood as an emergent characteristic of the explosion of semantic complexity that occurred during hominid evolution. It is argued that grammatical rules used in given languages are likely to be simply conventionalized, invented features of language, and not the result of an innate, grammar-specific module. The grammatical and syntactic regularities that are found across languages occur simply because all languages attempt to communicate the same sorts of semantic information.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008360020568
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    The Evolution of a Scientific Concept (1999)
    Springer
    Journal for general philosophy of science 30 (1999), S. 37-58 
    Details
    ISSN: 1572-8587
    Keywords: protein ; experimentation ; conceptual variation and selection ; evolution ; Mulder ; Liebig ; Pflüger ; Nägeli
    Source: Springer Online Journal Archives 1860-2000
    Topics: Philosophy , Nature of Science, Research, Systems of Higher Education, Museum Science
    Notes: Abstract A philosophically comprehended account is given of the genesis and evolution of the concept of protein. Characteristic of this development were not shifts in theory in response to new experimental data, but shifts in the range of questions that the available experimental resources were fit to cope with effectively. Apart from explanatory success with regard to its own range of questions, various other selecting factors acted on a conceptual variant, some stemming from a competing set of research questions, others from an altogether different field of inquiry, and still others from the external environment. These results are best explained on, hence support, an evolutionary model of the progress of experimental investigation, whose outlines are briefly discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008246507186
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Effects of repeated manure and fertilizer phosphorus additions on soil phosphorus dynamics under a soybean-wheat rotation (1999)
    Springer
    Biology and fertility of soils 28 (1999), S. 150-155 
    Details
    ISSN: 1432-0789
    Keywords: Key words Phosphorus dynamics ; Olsen ; phosphorus ; Soil phosphorus fractions ; Manure ; Soybean-wheat rotation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract  Soil P availability and efficiency of applied P may be improved through an understanding of soil P dynamics in relation to management practices in a cropping system. Our objectives in this study were to evaluate changes in plant-available (Olsen) P and in different inorganic P (Pi) and organic P (P0) fractions in soil as related to repeated additions of manure and fertilizer P under a soybean-wheat rotation. A field experiment on a Typic Haplustert was conducted from 1992 to 1995 wherein the annual treatments included four rates of fertilizer P (0, 11, 22 and 44 kg ha–1 applied to both soybean and wheat) in the absence and presence of 16 t ha–1 of manure (applied to soybean only). With regular application of fertilizer P to each crop the level of Olsen P increased significantly and linearly through the years in both manured and unmanured plots. The mean P balance required to raise Olsen P by 1 mg kg–1 was 17.9 kg ha–1 of fertilizer P in unmanured plots and 5.6 kg ha–1 of manure plus fertilizer P in manured plots. The relative sizes of labile [NaHCO3-extractable Pi (NaHCO3-Pi) and NaHCO3-extractable P0 (NaHCO3-P0)], moderately labile [NaOH-extractable Pi (NaOH-Pi) and NaOH-extractable P0 (NaOH-P0)] and stable [HCl-extractable P (HCl-P) and H2SO4/H2O2-extractable P (resisual-P)] P pools were in a 1 : 2.9 : 7.6 ratio. Application of fertilizer P and manure significantly increased NaHCO3-Pi and -P0 and NaOH-Pi, and -P0 fractions and also total P. However, HCl-P and residual-P were not affected. The changes in NaHCO3-Pi, NaOH-Pi and NaOH-P0 fractions were significantly correlated with the apparent P balance and were thought to represent biologically dynamic soil P and act as major sources and sinks of plant-available P.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s003740050477
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 11
    Electronic Resource
    Electronic Resource
    Stable isotope (δ13C and δ15N) signatures of sedimented organic matter as indicators of historic lake trophic state (1999)
    Springer
    Journal of paleolimnology 22 (1999), S. 205-221 
    Details
    ISSN: 1573-0417
    Keywords: carbon isotopes ; diatoms ; lake management ; nitrogen isotopes ; phosphorus ; radium-226 ; sediments ; trophic state
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract We explored the use of carbon and nitrogen isotopes (δ13C and δ15N) in sedimented organic matter (OM) as proxy indicators of trophic state change in Florida lakes. Stable isotope data from four 210Pb-dated sediment cores were compared stratigraphically with established proxies for historical trophic state (diatom-inferred limnetic total phosphorus, sediment C/N ratio) and indicators of cultural disturbance (sediment total P and 226Ra activity). Diatom-based limnetic total P inferences indicate a transition from oligo-mesotrophy to meso-eutrophy in Clear Lake, and from eutrophy to hypereutrophy in Lakes Parker, Hollingsworth and Griffin. In cores from all four lakes, the carbon isotopic signature of accumulated OM generally tracks trophic state inferences and cultural impact assessments based on other variables. Oldest sediments in the records yield lower diatom-inferred total limnetic P concentrations and display relatively low δ13C values. In the Clear, Hollingsworth and Parker records, diatom-inferred nutrient concentrations increase after ca. AD 1900, and are associated stratigraphically with higher δ13C values in sediment OM. In the Lake Griffin core, both proxies display slight increases before ~1900, but highest values occur over the last ~100 years. As Lakes Clear, Hollingsworth and Parker became increasingly nutrient-enriched over the past century, the δ15N of sedimented organic matter decreased. This reflects, in part, the increasing relative contribution of nitrogen-fixing cyanobacteria to sedimented organic matter as primary productivity increased in these waterbodies. The Lake Griffin core displays a narrow range of both δ13C and δ15N values. Despite the complexity of carbon and nitrogen cycles in lakes, stratigraphic agreement between diatom-inferred changes in limnetic total P and the stable isotope signatures of sedimented OM suggests that δ13C and δ15N reflect shifts in historic lake trophic state.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008078222806
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 12
    Electronic Resource
    Electronic Resource
    Calibration of diatoms along a nutrient gradient in Florida Everglades Water Conservation Area-2A, USA (1999)
    Springer
    Journal of paleolimnology 22 (1999), S. 413-437 
    Details
    ISSN: 1573-0417
    Keywords: diatoms ; Everglades ; phosphorus ; wetland ; calibration ; multivariate ; Florida
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract The relationship between diatom taxa preserved in surface soils and environmental variables at 31 sites in Water Conservation Area 2A (WCA-2A) of the Florida Everglades was explored using multivariate analyses. Surface soils were collected along a phosphorus (P) gradient and analyzed for diatoms, total P, % nitrogen (N), %carbon (C), calcium (Ca), and biogenic silica (BSi). Phosphorus varied from 315-1781 μg g-1, and was not found to be correlated with the other geochemical variables. Canonical correspondence analysis (CCA) was used to examine which environmental variables correlated most closely with the distributions in diatom taxa. Canonical correspondence analysis with forward selection, constrained and partial CCA, and Monte Carlo permutation tests of significance show the most significant changes in diatom assemblages along the P gradient (p 〈 0.01), with additional species differences correlated with soil C, N, Ca, and BSi. Weighted-averaging (WA) regression and calibration models of diatom assemblages to P and BSi were developed. The diatom-based inference model for soil [P] had a high apparent r2 (0.86) with RMSEboot = 218 μg g-1. Indicator diatom species identified by assessing species WA optima and WA tolerance to [P], such as Nitzschia amphibia and N. palea for high [P] (~1300-1400 μ g-1) and Achnanthes minutissima var. scotica and Mastogloia smithii for low [P] (~400-600 μg g-1), may be useful as monitoring tools for eutrophication in WCA-2A as well as other areas of the Everglades. Diatom assemblages analyzed by cluster analysis were related to location within WCA-2A, and dominant taxa within clusters are discussed in relation to the geochemical variables measured as well as hydrology and pH. Diversity of diatom assemblages and a ‘Disturbance Index’ based on diatom data are discussed in relation to the historically P-limited Everglades ecosystem. Diatom assemblages should be very useful for reconstructions of [P] through time in the Florida Everglades, provided diatoms are well preserved in soil cores.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008049224045
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 13
    Electronic Resource
    Electronic Resource
    Controlling soil water content in fertiliser dissolution experiments (1999)
    Springer
    Nutrient cycling in agroecosystems 55 (1999), S. 7-14 
    Details
    ISSN: 1573-0867
    Keywords: fertiliser formulation ; nutrients ; phosphorus ; relative humidity ; soil moisture
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Phosphorus lost in runoff from agricultural land leads to the enrichment of surface waters and contributes to algal blooms. Fertilisers are one source of this P. To compare the water available P of different fertiliser formulations in the laboratory it is necessary to control environmental conditions, temperature, relative humidity and soil water content, prior to simulating rainfall. Two chambers were designed in which relative humidity and soil water content were controlled using salt solutions. An initial design comprising a sealed chamber with three layers of soil samples over a salt bath was found to be inferior to a single layer design. The changes in water content of soil samples were used to test the single layer chamber in a constant temperature environment (15 °C) using a saturated KCl solution (90% relative humidity). Based on the final soil water content of the samples, the spatial variation within the chamber was within tolerable limits. The single layer chamber was used for a simulation experiment comparing the water available P of two commercial fertilisers. Using a saturated resorcinol solution (95% relative humidity) soil samples were equilibrated at 15 °C for 21 days, fertiliser added, and the water available P measured up to 600 h after fertiliser application. The results indicate that the amount of water available P was related to the fertiliser compound and exponentially related to the time since fertiliser application. It was concluded that the single layer chamber is suitable for controlling relative humidity and soil water content in trials such as these where the water available P of fertilisers are being compared.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009816716466
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 14
    Electronic Resource
    Electronic Resource
    Transfers of phosphorus within three dairy farming systems receiving varying inputs in feeds and fertilizers (1999)
    Springer
    Nutrient cycling in agroecosystems 55 (1999), S. 63-75 
    Details
    ISSN: 1573-0867
    Keywords: dairy systems ; feeds ; fertilizers ; phosphorus ; P surplus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Inputs of phosphorus (P) above requirements for production on dairy farms lead to surplus P with increased risk of P transfer in land run-off to surface waters causing eutrophication. The impact of reducing surplus P inputs in purchased feeds and fertilizers on milk and forage production was investigated in a comparison of three dairy farm systems on chalkland soils in southern England over a 3-year period. In accordance with current commercial practice, no attempt was made to regulate P inputs in system 1, which accumulated an average annual surplus of 23 kg P ha-1. Progressive reductions in purchased feed and/or fertilizer inputs into systems 2 and 3 decreased surplus P to 17 and 3 kg ha-1, respectively, without apparently limiting either milk or herbage dry matter production. The estimated reduction in faecal P output from system 3 cows fed a low P diet compared to system 1 cows fed a high P diet was 26%. Milk P concentrations significantly (P 〈0.001) increased in systems 2 and 3 which included maize in the diet. Output of P in milk and meat products, as a proportion of the total dietary P inputs, increased from 28% in system 1 to 36% in system 3. Surplus P was greatest in continuous maize fields receiving both dairy manure and starter P fertilizer. Withholding P fertilizer in system 3 did not reduce P offtake in cut herbage on soils of moderate P fertility. Total annual losses of P in storm run-off and leaching were no greater than annual inputs of P from the atmosphere (0.5 kg ha-1). The results indicate there is scope to reduce surplus P on commercial dairy farms without sacrificing production targets at least in the short term. Purchased feeds are the largest of the P inputs on intensive dairy farms, yet these are rarely quantified on commercial holdings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009860915462
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 15
    Electronic Resource
    Electronic Resource
    Applications of poultry litter and triple superphosphate fertilizer to a sandy soil: effects on soil phosphorus status and profile distribution (1999)
    Springer
    Nutrient cycling in agroecosystems 54 (1999), S. 233-242 
    Details
    ISSN: 1573-0867
    Keywords: leaching ; phosphorus ; poultry litter ; soil
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract To determine P loadings, added through poultry litter, sufficient to cause downward movement of P from the cultivated layer of a sandy soil, six rates of poultry litter were applied annually for four years to a site in central England. (total loading 0 – 1119 kg P ha-1). A single extra plot also received an extra 1000 kg ha-1 as triple superphosphate (TSP; total loading 2119 kg P ha-1) and three other treatments received 200 – 800 kg ha-1 P as TSP only. Annual soil sampling in 30-cm increments to 1.5-m depth provided information on P build-up in the topsoil and P movement to depth. There were strong linear trends between P balance (P applied – P removed in crops) and total P, Olsen bicarbonate extractable P and water-soluble P in the topsoil. Phosphorus from TSP and poultry litter fell on the same regression lines, suggesting that both would be equally effective as fertilizer sources. We calculated that 100 kg ha-1 surplus total P would increase the Olsen extractable P content by c. 6 mg kg-1 and the water-soluble P by c. 5 mg kg-1. Thus, relatively large amounts of P would need to be applied to raise soil P status. We found some evidence of P movement into the soil layers immediately below cultivation depth. However, neither soil sampling nor soil solution extracted through Teflon water samplers showed evidence of movement into the deep subsoil (1 m) despite large P loadings.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009744706679
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 16
    Electronic Resource
    Electronic Resource
    Inorganic phosphorus and manure effects on bahiagrass production on a Spodosol (1999)
    Springer
    Nutrient cycling in agroecosystems 54 (1999), S. 259-266 
    Details
    ISSN: 1573-0867
    Keywords: bahiagrass ; manure ; pasture fertilization ; phosphorus ; phosphorus cycling ; Spodosol
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Bahiagrass (Paspalum notatum Flugge) pasture fertilization recommendations have traditionally been based upon clipping studies. Inclusion of P from manure, not originally considered when P recommendations were developed for pastures, may minimize the need for P fertilization without reducing bahiagrass production or P uptake. The objective of this research was to determine if manure contributes greatly to the P crop nutrient requirement. A 2-year field study utilized a factorial arrangement of 0 and 6.9 Mg air-dried manure ha-1 with 0, 17, 34, 51, and 68 kg inorganic P ha-1 from triple superphosphate to evaluate bahiagrass yield, root distribution, and P uptake response on a Myakka fine sand (sandy, siliceous, hyperthermic Aeric Alaquod). Because air-dried manure was used in the field study, a greenhouse study was employed to confirm that there were no differences in bahiagrass yield or P uptake from either air-dried or fresh cattle (Bos spp.) manure sources. There were no manure or manure by P interaction effects on yield or P uptake of bahiagrass indicating that manure source did not effect grass production in the greenhouse. In the field study, bahiagrass roots were distributed into the Bh horizon, and the Bh horizon had at least four times more Mehlich-1 extractable P than that of the Ap horizon. This horizon was most likely acting as a main source for P-uptake by the grass. This observation was further confirmed by no yield response to levels of inorganic P application in 1989. A linear-response-and-plateau (R2=0.196) relationship with a critical point of 15.4 kg P ha-1 was found in 1990. Bahiagrass yield and P uptake were not dependent on P fertilization, either from manure or inorganic P, due to the availability of P from the Bh horizon.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009831011649
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 17
    Electronic Resource
    Electronic Resource
    Robert Chambers and Thomas Henry Huxley, Science Correspondents: The Popularization and Dissemination of Nineteenth Century Natural Science (1999)
    Springer
    Journal of the history of biology 32 (1999), S. 343-383 
    Details
    ISSN: 1573-0387
    Keywords: agnosticism ; Darwinian ; evolution ; materialism ; Malthusian ; nebular hypothesis ; popularization ; professionalization ; transitional forms
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , History
    Notes: Abstract Robert Chambers and Thomas Henry Huxley helped popularize science by writing for general interest publications when science was becoming increasingly professionalized. A non-professional, Chambers used his family-owned Chambers' Edinburgh Journal to report on scientific discoveries, giving his audience access to ideas that were only available to scientists who regularly attended professional meetings or read published transactions of such forums. He had no formal training in the sciences and little interest in advancing the professional status of scientists; his course of action was determined by his disability and interest in scientific phenomena. His skillful reporting enabled readers to learn how the ideas that flowed from scientific innovation affected their lives, and his series of article in the Journal presenting his rudimentary ideas on evolution, served as a prelude to his important popular work, Vestiges of the Natural History of Creation. Huxley, an example of the new professional class of scientists, defended science and evolution from attacks by religious spokesmen and other opponents of evolution, informing the British public about science through his lectures and articles in such publications as Nineteenth Century. He understood that by popularizing scientific information, he could effectively challenge the old Tory establishment -- with its orthodox religious and political views -- and promote the ideas of the new class of professional scientists. In attempting to transform British society, he frequently came in conflict with theologians and others on issues in which science and religion seemed to contradict each other but refused to discuss matters of science with non-professionals like Chambers, whose popular writing struck a more resonant chord with working class readers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004616403134
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 18
    Electronic Resource
    Electronic Resource
    Evidence for an HLA-C-like locus in the orangutan Pongo pygmaeus (1999)
    Springer
    Immunogenetics 49 (1999), S. 865-871 
    Details
    ISSN: 1432-1211
    Keywords: Key words Orangutan ; MHC class I ; HLA-C ; natural killer cells ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract  HLA-B and C are related class I genes which are believed to have arisen by duplication of a common ancestor. Previous study showed the presence of orthologues for both HLA-B and C in African apes but only for HLA-B in Asian apes. These observations suggested that the primate C locus evolved subsequent to the divergence of the Pongidae and Hominidae. From an analysis of orangutan Tengku two HLA-C-like alleles (Popy C*0101 and Popy C*0201) were defined as well as three HLA-B-like (Popy-B) alleles. By contrast, no Popy-C alleles were obtained from orangutan Hati, although three Popy-B alleles were defined. Thus an HLA-C-like locus exists in the orangutan (as well as a duplicated B locus), implying that the primate C locus evolved prior to the divergence of the Pongidae and Hominidae and is at least 12–13 million years old. Uncertain is whether all orangutan MHC haplotypes contain a C locus, as the failure to find C alleles in some individuals could be due to a mispairing of HLA-C-specific primers with certain Popy-C alleles. These results raise the possibilities that other primate species have a C locus and that the regulation of natural killer cells by C allotypes evolved earlier in primate evolution than has been thought.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002510050566
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 19
    Electronic Resource
    Electronic Resource
    Regulation of cardiomyocyte apoptosis in ischemic reperfused mouse heart by glutathione peroxidase (1999)
    Springer
    Molecular and cellular biochemistry 196 (1999), S. 13-21 
    Details
    ISSN: 1573-4919
    Keywords: apoptosis ; DNA fragmentation ; GSHPx-1 knockout mice ; GSHPx-1 transgenic mice ; ischemia/repurfusion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Apoptosis, a genetically controlled programmed cell death, has been found to play a role in ischemic reperfusion injury in several animal species including rats and rabbits. To examine whether this is also true for other animals, an isolated perfused mouse heart was subjected to 30 min of ischemia followed by 2 h of reperfusion. Experiments were terminated before ischemia (baseline), after ischemia, and at 30, 60, 90 and 120 min of reperfusion. At the end of each experiment, hearts were processed for the evaluation of apoptosis and DNA laddering. The in situ end labeling (ISEL) technique was used to detect apoptotic cardiomyocyte nuclei while DNA laddering was evaluated by subjecting the DNA obtained from the cardiomyocytes to 1.8% agarose gel electrophoresis followed by photographing under UV illumination. The results of our study revealed that apoptotic cells appear only after 60 min of reperfusion as demonstrated by the intense fluorescence of the immunostained genomic DNA when observed under fluorescence microscopy. None of the ischemic hearts showed any evidence of apoptosis. These results were corroborated with the findings of DNA fragmentation showing increased ladders of DNA bands in the same reperfused hearts representing integer multiples of the internucleosomal DNA length (about 180 bp). Since our previous studies showed a role of glutathione peroxidase (GSHPx) in apoptotic cell death, we performed identical experiments using isolated hearts from GSHPx-l knockout mice and transgenic mice overexpressing GSHPx-l. GSHPx-l knockout mice showed evidence of apoptotic cell death even after 30 min of reperfusion. Significant number of apoptotic cells were found in the cardiomyocytes as compared to non-transgenic control animals. To the contrary, very few apoptotic cells were found in the hearts of the transgenic mice overexpressing GSHPx-l. Hearts of GSHPx-l knockout mice were more susceptible to ischemia/reperfusion injury while transgenic mice overexpressing GSHPx- 1 were less susceptible to ischemia reperfusion injury compared to non-transgenic control animals. The results of this study clearly demonstrate a role of GSHPx in ischemia/reperfusion-induced apoptosis in mouse heart.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006905910140
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 20
    Electronic Resource
    Electronic Resource
    Human DU145 prostate cancer cells overexpressing mitogen-activated protein kinase phosphatase-1 are resistant to Fas ligand-induced mitochondrial perturbations and cellular apoptosis (1999)
    Springer
    Molecular and cellular biochemistry 199 (1999), S. 169-178 
    Details
    ISSN: 1573-4919
    Keywords: MKP-1 ; Fas ligand ; Fas ; apoptosis ; prostate cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Recent studies have suggested that MAP kinase phosphatase 1 (MKP-1) is overexpressed in prostate cancer. To evaluate the role of MKP-1 in regulating cell death and tumor growth in prostate cancer, MKP-1 was conditionally overexpressed in the human prostate cancer cell line DU145. Overexpression of MKP-1 in DU145 cells blocked activation of stress-activated protein kinase (SAPK/JNK). MKP-1 overexpression in DU-145 cells was also found to inhibit Fas ligand (FasL)-induced apoptosis, as well as block the activation of caspases by Fas engagement. In addition, MKP-1 blocked the activation of apoptosis by transfected MEKK-1 and ASK-1, presumably through its inhibition of the SAPK/JNK family of enzymes. MKP-1 blocked the ability of FasL to induce loss of mitochondrial transmembrane potential (Δγm), suggesting that MKP-1 acts upstream of mitochondrial pro-apoptotic events induced by FasL and that the SAPK/JNK pathway may form the signaling link between Fas receptor and mitochondrial dysfunction. Thus, MKP-1 overexpression in prostate cancer may play a role in promoting prostate carcinogenesis by inhibiting FasL-induced cell death.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006980326855
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 21
    Electronic Resource
    Electronic Resource
    Poly(ADP-ribosylation) and apoptosis (1999)
    Springer
    Molecular and cellular biochemistry 199 (1999), S. 125-137 
    Details
    ISSN: 1573-4919
    Keywords: apoptosis ; ADP-ribosylation ; caspases ; PARP ; PARG
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Poly(ADP-ribosylation) is a post-translational modification playing a relevant role in DNA damage recovery, DNA replication and viral integration. Several reports also suggest a modulation of this process during cell death by apoptosis. The aim of this review is to discuss the possible involvement of poly(ADP-ribosylation) during apoptosis, by dealing with general considerations on apoptosis, and further examining the correlation between NAD consumption and cell death, the regulation of poly(ADP-ribose) metabolism in apoptotic cells, the effect of poly(ADP-ribose) polymerase inhibition on cell death occurrence and the use of enzyme cleavage as a marker of apoptosis. Finally, the future prospects of the research in this area will be addressed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006962716377
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 22
    Electronic Resource
    Electronic Resource
    A dual approach in the study of poly (ADP-ribose) polymerase: In vitro random mutagenesis and generation of deficient mice (1999)
    Springer
    Molecular and cellular biochemistry 193 (1999), S. 53-60 
    Details
    ISSN: 1573-4919
    Keywords: DNA binding protein ; NAD metabolism ; cellular response to DNA damage ; γ-rays ; alkylating agents ; genomic instability ; apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract A dual approach to the study of poly (ADP-ribose)polymerase (PARP) in terms of its structure and function has been developed in our laboratory. Random mutagenesis of the DNA binding domain and catalytic domain of the human PARP, has allowed us to identify residues that are crucial for its enzymatic activity. In parallel PARP knock-out mice were generated by inactivation of both alleles by gene targeting. We showed that: (i) they are exquisitely sensitive to γ-irradiation, (ii) they died rapidly from acute radiation toxicity to the small intestine, (iii) they displayed a high genomic instability to γ-irradiation and MNU injection and, (iv) bone marrow cells rapidly underwent apoptosis following MNU treatment, demonstrating that PARP is a survival factor playing an essential and positive role during DNA damage recovery and survival.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006947707713
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 23
    Electronic Resource
    Electronic Resource
    Involvement of PARP and poly(ADP-ribosyl)ation in the early stages of apoptosis and DNA replication (1999)
    Springer
    Molecular and cellular biochemistry 193 (1999), S. 137-148 
    Details
    ISSN: 1573-4919
    Keywords: PARP ; poly(ADP-ribosyl)ation ; apoptosis ; DNA replication
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract We have focused on the roles of PARP and poly(ADP-ribosyl)ation early in apoptosis, as well as during the early stages of differentiation-linked DNA replication. In both nuclear processes, a transient burst of PAR synthesis and PARP expression occurs early, prior to internucleosomal DNA cleavage before commitment to apoptosis as well as at the round of DNA replication prior to the onset of terminal differentiation. In intact human osteosarcoma cells undergoing spontaneous apoptosis, both PARP and PAR decreased after this early peak, concomitant with the inactivation and cleavage of PARP by caspase-3 and the onset of substantial DNA and nuclear fragmentation. Whereas 3T3-L1, osteosarcoma cells, and immortalized PARP +/+ fibroblasts exhibited this early burst of PAR synthesis during Fas-mediated apoptosis, neither PARP-depleted 3T3-L1 PARP-antisense cells nor PARP -/- fibroblasts showed this response. Consequently, whereas control cells progressed into apoptosis, as indicated by induction of caspase-3-like PARP-cleavage activity, PARP-antisense cells and PARP -/- fibroblasts did not, indicating a requirement for PARP and poly(ADP-ribosyl)ation of nuclear proteins at an early reversible stage of apoptosis. In parallel experiments, a transient increase in PARP expression and activity were also noted in 3T3-L1 preadipocytes 24 h after induction of differentiation, a stage at which ~95% of the cells were in S-phase, but not in PARP-depleted antisense cells, which were consequently unable to complete the round of DNA replication required for differentiation. PARP, a component of the multiprotein DNA replication complex (MRC) that catalyzes viral DNA replication in vitro, poly(ADP-ribosyl)ates 15 of ~40 MRC proteins, including DNA pol α, DNA topo I, and PCNA. Depletion of endogenous PARP by antisense RNA expression in 3T3-L1 cells results in MRCs devoid of any DNA pol α and DNA pol δ activities. Surprisingly, there was no new expression of PCNA and DNA pol α, as well as the transcription factor E2F-1 in PARP-antisense cells during entry into S-phase, suggesting that PARP may play a role in the expression of these proteins, perhaps by interacting with a site in the promoters for these genes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006988832729
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 24
    Electronic Resource
    Electronic Resource
    Bcl-2, survivin and variant CD44 v7-v10 are downregulated and p53 is upregulated in breast cancer cells by progesterone: Inhibition of cell growth and induction of apoptosis (1999)
    Springer
    Molecular and cellular biochemistry 202 (1999), S. 53-61 
    Details
    ISSN: 1573-4919
    Keywords: breast cancer cells ; anti-apoptotic genes ; apoptosis ; progesterone
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Progesterone inhibits the proliferation of normal breast epithelial cells in vivo, as well as breast cancer cells in vitro. But the biologic mechanism of this inhibition remains to be determined. We explored the possibility that an antiproliferative activity of progesterone in breast cancer cell lines is due to its ability to induce apoptosis. Since p53, bcl-2 and survivin genetically control the apoptotic process, we investigated whether or not these genes could be involved in the progesterone-induced apoptosis. We found a maximal 90% inhibition of cell proliferation with T47-D breast cancer cells after exposure to 10 μM progesterone for 72 h. Control progesterone receptor negative MDA-231 cancer cells were unresponsive to 10 μM progesterone. The earliest sign of apoptosis is translocation of phosphatidylserine from the inner to the outer leaflet of the plasma membrane and can be monitored by the calcium-dependent binding of annexin V in conjunction with flow cytometry. After 24 h of exposure to 10 μM progesterone, cytofluorometric analysis of T47-D breast cancer cells indicated 43% were annexin V-positive and had undergone apoptosis and no cells showed signs of cellular necrosis (propidium iodide negative). After 72 h of exposure to 10 μM progesterone, 48% of the cells had undergone apoptosis and 40% were annexin V positive/propidium iodide positive indicating signs of necrosis. Control untreated cancer cells did not undergo apoptosis. Evidence proving apoptosis was also demonstrated by fragmentation of nuclear DNA into multiples of oligonucleosomal fragments. After 24 h of exposure of T47-D cells to either 1 or 10 μM progesterone, we observed a marked down-regulation of protooncogene bcl-2 protein and mRNA levels. mRNA levels of survivin and the metastatic variant CD44 v7-v10 were also downregulated. Progesterone increased p53 mRNA levels. These results demonstrate that progesterone at relative high physiological concentrations, but comparable to those seen in plasma during the third trimester of human pregnancy, exhibited a strong antiproliferative effect on breast cancer cells and induced apoptosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007081021483
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 25
    Electronic Resource
    Electronic Resource
    Role of nitric oxide in the induction of apoptosis by smokeless tobacco extract (1999)
    Springer
    Molecular and cellular biochemistry 200 (1999), S. 51-57 
    Details
    ISSN: 1573-4919
    Keywords: smokeless tobacco ; apoptosis ; nitric oxide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Smokeless tobacco usage is, a growing public health concern in the United States. Lesions of the oral cavity have been clearly linked to smokeless tobacco use. The objective of this study was to determine the biochemical effects of smokeless tobacco extract (STE) exposure upon hamster cheek pouch cell (HCPC-1) cultures. HCPC-1 cells were exposed to a 5 -fold dose-range of STE (0.5, 1.0 and 2.5%) over a time-course of 24-96 h. Following each exposure we measured various biochemical parameters of cell proliferation and cell death. Cell viability, cell cycle progression and S-phase DNA synthesis were measured as markers of cell proliferation. We measured lactate dehydrogenase leakage as a marker of cell membrane damage and cell death due to necrosis. No significant alterations were observed in cell cycle progression and cell proliferation as a result of exposure to STE. LDH measured colorimetrically indicated no significant effect with the lower doses (0.5, 1.0 and 2.5% STE). Apoptosis measured as the A0 peak and by the TUNEL procedure revealed that STE caused significant rates of apoptosis. Maximal apoptosis was noted between 48-96 h. In order to probe the mechanism further we measured the levels of nitrites as an indicator of nitric oxide (NO) in the media. NO levels were significantly elevated at the doses that caused an induction of apoptosis. The results from this study indicate that STE causes a dose-dependent induction of apoptosis and that this is mediated by nitric oxide.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006985700851
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 26
    Electronic Resource
    Electronic Resource
    From Chemical to Population Ecology: Infochemical Use in an Evolutionary Context (1999)
    Springer
    Journal of chemical ecology 25 (1999), S. 31-49 
    Details
    ISSN: 1573-1561
    Keywords: Chemical ecology ; evolution ; variation ; population dynamics ; community ; species interactions ; infochemical ; semiochemical ; parasitoid ; foraging behavior ; learning ; phenotypic plasticity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The marriage of chemistry with ecology has been a productive one, providing a wealth of examples of how chemicals play important roles in the loves and lives of living organisms. At first the marriage may have been a simple and monogamous one with the major scientific aim of making proximate analyses of chemically mediated, individual level interactions. But times have changed and chemical ecology is broadening, embracing different approaches and disciplines. There is, for example, increasing appreciation of variability in the systems under study and an increase in evolutionary thinking. Another promising development is greater recognition of the potential importance of chemically mediated interactions for population dynamics and for structuring communities and species coexistence. The latter is an utterly underexplored area in chemical ecology. The field of chemical ecology of insect parasitoids shows some of these promising developments. Responses of parasitoids to infochemicals are increasingly studied with an integrated approach of mechanism and function. This integration of “how” and “why” questions significantly enhances the evolutionary and ecological understanding of stimulus–response patterns. The future challenge in chemical ecology is to demonstrate how chemically mediated interactions steer ecological and evolutionary processes at all levels of ecological organization. To reach this goal there is a need for interdisciplinary collaboration among chemists and ecologists working at different levels of organization and with different approaches, with other disciplines as partners.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1020833015559
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 27
    Electronic Resource
    Electronic Resource
    Clostridial toxins: Molecular probes of Rho-dependent signaling and apoptosis (1999)
    Springer
    Molecular and cellular biochemistry 193 (1999), S. 37-42 
    Details
    ISSN: 1573-4919
    Keywords: Rho ; GTPase ; toxins ; Clostridium ; signal transduction ; apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The Rho family small GTPases are members of the Ras superfamily of small GTPases. Rho proteins were first determined to act as key regulators of many types of actin cytoskeletal-dependent cellular functions. Recent work by several investigators indicates that Rho GTPases are also critical modulators of several important intracellular and nuclear signal transduction pathways. Certain clostridial toxins and exoenzymes covalently modify, and thereby inactivate, specific types of Rho family GTPases. As such, these microbial enzymes have proven invaluable in helping to identify structural and functional attributes of Rho GTPases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006939505896
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 28
    Electronic Resource
    Electronic Resource
    Functional analysis of poly(ADP-ribose) polymerase in Drosophila melanogaster (1999)
    Springer
    Molecular and cellular biochemistry 193 (1999), S. 103-108 
    Details
    ISSN: 1573-4919
    Keywords: Poly(ADP-ribose) polymerase ; Drosophila melanogaster ; alternative splicing ; apoptosis ; DNA repair ; development
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Poly(ADP-ribose) polymerase (PARP) is conserved in eukaryotes. To analyze the function of PARP, we isolated and characterized the gene for PARP in Drosophila melanogaster. The PARP gene consisted of six translatable exons and spanned more than 50 kb. The DNA binding domain is encoded by exons 1-4. Although the consensus cleavage site of CED-3 like protease during apoptosis is conserved from human to Xenopus laevis PARPs, it is neither conserved in the corresponding region of Drosophila nor Sarcophaga peregrina. There are two cDNAs species in Drosophila. One cDNA could encode the full length PARP protein (PARP I), while the other is a truncated cDNA which could encode a partial-length PARP protein (PARP II), which lacks the automodification domain and is possibly produced by alternative splicing. The expression of these two forms of PARP in E. coli demonstrated that while PARP II has the catalytic NAD-binding domain and DNA-binding domain it is enzymatically inactive. On the other hand PARP I is active. A deletion mutant of PARP gene could grow to the end of embryogenesis but did not grow to the adult fly. These results suggest that the PARP gene plays an important function during the development of Drosophila.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006920429095
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 29
    Electronic Resource
    Electronic Resource
    Newly discovered anti-inflammatory properties of the benzamides and nicotinamides (1999)
    Springer
    Molecular and cellular biochemistry 193 (1999), S. 119-125 
    Details
    ISSN: 1573-4919
    Keywords: benzamides ; nicotinamides ; apoptosis ; inflammation ; NF-kB ; DNA repair
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Our laboratory has concentrated on the possible regulation the benzamides and nicotinamides may have on the processes of DNA repair and apoptosis. Recent reports [14-16] have suggested that both apoptosis and inflammation are regulated by the transcription factor NF-kB. We have initiated studies regarding the hypothesis that the benzamides and nicotinamides could inhibit the production of tumor necrosis factor alpha (TNFalpha) and the inflammatory response as well as induce apoptosis via inhibition of NF-kB. Our data have shown that nicotinamide and two N-substituted benzamides, metoclopramide (MCA) and 3-chloroprocainamide (3-CPA), gave dose dependent inhibition of lipopolysacharide induced TNFalpha in the mouse within the dose range of 10-500 mg/kg. Moreover, lung edema was prevented in the rat by 3 ï 50 mg/kg doses of 3-CPA or MCA, and 100-200 μM doses of MCA could also inhibit NF-kB in Hela cells. Taken together these data strongly support the notion that benzamides and nicotinamides have potent anti-inflammatory and antitumor properties, because their primary mechanism of action is regulated by inhibition at the gene transcription level of NF-kB, which in turn inhibits TNFalpha and induces apoptosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006932714982
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 30
    Electronic Resource
    Electronic Resource
    Growth arrest and induction of apoptosis in breast cancer cells by antisense depletion of protein kinase A-RIα subunit: p53-independent mechanism of action (1999)
    Springer
    Molecular and cellular biochemistry 195 (1999), S. 25-36 
    Details
    ISSN: 1573-4919
    Keywords: antisense oligonucleotide ; apoptosis ; cAMP-dependent protein kinase ; cancer cells ; growth inhibition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The enhanced expression of the RIα subunit of cyclic AMP-dependent protein kinase type 1 (PKA-I) has been correlated with cancer cell growth. We have investigated the effects of sequence-specific inhibition of RIα gene expression on the growth of MCF-7 human breast cancer cells. We report that RIα antisense treatment results in a reduction in RIα expression at both mRNA and protein levels and inhibition of cell growth. The growth inhibition was accompanied by changes in cell morphology, cleavage of poly(ADP-ribose) polymerase (PARP) and appearance of apoptotic nuclei. In addition, bcl-2 protein level was reduced and p53 expression increased in growth arrested cells. Interestingly, RIα antisense inhibited cell viability and induced apoptosis in the absence of p53, suggesting that these actions of RIα antisense are exerted independent of p53. In contrast, two- and four-base mismatched control oligonucleotides had no effect on either cell growth or morphology. These results demonstrate that the RIα antisense, which efficiently depletes the growth stimulatory molecule RIα, induces cell differentiation and apoptosis, providing a new approach to combat breast cancer cell growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006990231186
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 31
    Electronic Resource
    Electronic Resource
    TNF-α induced altered signaling mechanism in human neutrophil (1999)
    Springer
    Molecular and cellular biochemistry 197 (1999), S. 97-108 
    Details
    ISSN: 1573-4919
    Keywords: neutrophil ; PKC ; TNF-α ; apoptosis ; DNA fragmentation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract In the present study we investigated the TNF-α induced signal transduction mechanism in human neutrophil. Exogenously added TNF-α affects both PKC activity and its translocation from cytosol to the membrane. Endogenous protein phosphorylation pattern is inhibited in TNF-α induced neutrophil in Ca-dependent and Ca-independent manner, including a major 47 and 66 kDa cytosolic proteins, which may be implicated in superoxide anion generation. However TNF-α dose dependently enhances the expression of ζ-PKC isotype but not the β-PKC. Morphology and cell cytotoxicity are studied in TNF-α treated neutrophil to understand the TNF-α induced cell death or apoptosis and these experiment is further confirmed by DNA fragmentation analysis. These results clearly demonstrate that TNF-α induces cellular death of human neutrophil at least in part by enhanced expression of Ca-independent ζ-PKC. These observations provide an insight towards understanding the function of ζ-PKC in apoptotic pathway.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006935114624
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 32
    Electronic Resource
    Electronic Resource
    Diminished energy metabolism and enhanced apoptosis in livers of B6C3F1 mice treated with the antihepatocarcinogen rotenone (1999)
    Springer
    Molecular and cellular biochemistry 201 (1999), S. 25-32 
    Details
    ISSN: 1573-4919
    Keywords: rotenone ; apoptosis ; oncogenes ; liver cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Rotenone decreases the incidence of hepatocellular carcinoma and lowers rates of hepatocellular proliferation. In an effort to delineate mechanisms involved, the in vivo effect of rotenone on liver mitochondrial metabolism, apoptotic machinery as well as elements of the hepatic signal transduction pathways were investigated. Mitochondria from livers of male B6C3F1 mice fed a standard diet containing 600 ppm rotenone for 7 days were uncoupled or inhibited when succinate or glutamate plus malate were used as the substrate, respectively. These livers also showed a significant increase in apoptosis compared with control livers. Furthermore, rotenone increased the expression of c-myc mRNA to 5-fold of control values within 3 days, an effect which was still observed (3-fold) after 7 days. Levels of p53 mRNA were also increased 3-fold after 1 day, but declined to control levels by 7 days. Rotenone also caused a transient, yet marked increase in liver particulate glyceraldehyde phosphate dehydrogenase (GAPDH) protein expression, while it did not alter the expression of the cytosolic form of the enzyme. Conversely, mRNA of the proto-oncogene H-ras showed a decline of 35% after 3 days of rotenone treatment, and remained diminished for the duration of the experiment. These data suggest that rotenone may act as an anticancer agent by diminishing mitochondrial bioenergetics which prevents basal hepatocyte proliferation and lowers the threshold for liver cells with DNA damage to undergo apoptosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007024905046
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 33
    Electronic Resource
    Electronic Resource
    The Amino Acid Sequence of Ribitol Dehydrogenase-F, a Mutant Enzyme with Improved Xylitol Dehydrogenase Activity (1999)
    Springer
    The protein journal 18 (1999), S. 489-495 
    Details
    ISSN: 1573-4943
    Keywords: Klebsiella aerogenes ; ribitol dehydrogenase ; evolution ; mutant structures
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A mutant ribitol dehydrogenase (RDH-F) was purified from Klebsiella aerogenes strain F which evolved from the wild-type strain A under selective pressure to improve growth on xylitol, a poor substrate used as sole carbon source. The ratio of activities on xylitol (500 mM) and ribitol (50 mM) was 0.154 for RDH-F compared to 0.033 for the wild-type (RDH-A) enzyme. The complete amino acid sequence of RDH-F showed the mutations. Q60 for E60 and V215 for L215 in the single polypeptide chain of 249 amino acid residues. Structural modeling based on homologies with two other microbial dehydrogenases suggests that E60 → Q60 is a neutral mutation, since it lies in a region far from the catalytic site and should not cause structural perturbations. In contrast, L215 → V215 lies in variable region II and would shift a loop that interacts with the NADH cofactor. Another improved ribitol dehydrogenase, RDH-D, contains an A196 → P196 mutation that would disrupt a surface α-helix in region II. Hence conformational changes in this region appear to be responsible for the improved xylitol specificity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1020601011846
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 34
    Electronic Resource
    Electronic Resource
    Preparative High-Resolution Two-Dimensional Electrophoresis Enables the Identification of RNA Polymerase B Transcription Factor 3 as an Apoptosis-Associated Protein in the Human BL60–2 Burkitt Lymphoma Cell Line (1999)
    Springer
    The protein journal 18 (1999), S. 225-231 
    Details
    ISSN: 1573-4943
    Keywords: Two-dimensional electrophoresis ; MALDI-MS ; apoptosis ; RNA polymerase B transcription factor 3
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Apoptosis or programmed cell death is essential in the process of controlling lymphocyte growth and selection. We identified RNA polymerase B transcription factor 3 (BTF3), which is associated with anti-IgM antibody-mediated apoptosis, using a subclone of the human Burkitt lymphoma cell line BL60. To identify the transcription factor BTF3, which is expressed only in minor amounts, we used preparative high-resolution two-dimensional gel electrophoresis (2DE) employing carrier ampholytes for isoelectric focusing. Comparison of the 2DE protein patterns from apoptotic and nonapoptotic cells showed BTF3 as a predominantly altered protein spot. The characterization of the differentially expressed transcription factor and 13 marker proteins described in this study were performed by internal Edman microsequencing and/or by peptide mass fingerprinting using matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The proteome analysis was significantly improved by performing the newly developed preparative high-resolution two-dimensional gels employing high protein concentrations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1020636308270
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 35
    Electronic Resource
    Electronic Resource
    Seed oil fatty acid patterns of theAconitum-Delphinium-Helleborus complex (Ranunculaceae) (1999)
    Springer
    Plant systematics and evolution 215 (1999), S. 37-47 
    Details
    ISSN: 1615-6110
    Keywords: Ranunculaceae ; Aconitum ; Delphinium ; Helleborus ; Nigella ; Seed oil ; fatty acids ; phylogeny ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Many members ofRanunculaceae contain unusual fatty acids in their seed oils. This leads to rather typical genus-specific fatty acid patterns or “fingerprints” in these seed oils. The members of theDelphinioideae and/orHelleboroideae, however, do not contain highly unusual fatty acids. Nevertheless, their seed oil fatty acid fingerprints are also fairly typical and genus-specific, and the patterns found are rather consistent throughout several species of one genus. It was found that species ofAconitum do not contain fatty acids with 20 carbon atoms.Delphinium, Consolida, Helleborus, Nigella and others do contain C20 fatty acids. In allHelleborus species, for example, there was a consistent C20 fatty acid pattern of 20:0≪20:1≫20:2〉20:3. Species ofNigella andGaridella contain high levels,Helleborus low levels, of 20:2n-6 in their seed oils.Delphinium andAconitum both contain low levels of 18:3n-3, whereasHelleborus spp. consistently show high levels of this fatty acid. The genus-specific fatty acid patterns found are discussed, and a correlation with the subfamily and tribe affiliation of the genera investigated here is attempted.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00984646
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 36
    Electronic Resource
    Electronic Resource
    Fruit differentiation, palynology, and systematics in theScabiosa group of genera andPseudoscabiosa (Dipsacaceae) (1999)
    Springer
    Plant systematics and evolution 216 (1999), S. 135-166 
    Details
    ISSN: 1615-6110
    Keywords: Dipsacaceae ; Pseudoscabiosa ; Scabiosa ; Sixalix ; Lomelosia ; Pycnocomon ; Scabiosiopsis ; Tremastelma ; Epicalyx ; fruit anatomy ; evolution ; systematics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Fruits ofDipsacaceae are single-seeded, have bristle-shaped calyx segments and are tightly enclosed by four fused bracts forming an epicalyx. Comparative morphological and anatomical studies reveal a great diversity of epicalyx and calyx, often relevant to fruit dispersal. The present contribution deals with theScabiosa group of genera, the core of theScabioseae tribe. Most of its taxa develop a diaphragma from a meristem on the inside of the epicalyx. This diaphragma, together with the lower part of the epicalyx encloses the fruit proper, whereas the upper parts form a so-called “epi-diaphragma” (ed) and a ± hyaline corona. Differences of the epicalyx with respect to the size and position of the ed, elaboration of the corona, origin of pits (=foveoles) and other morphological and anatomical specializations can be demonstrated. Together with palynological and karyological data these new facts support an improved concept of relationships and systematics for the taxa studied:Scabiosa sect.Scabiosa and sect.Cyrtostemma are closely related and should be united to form the genusScabiosa s. str.;Pycnocomon can be maintained as an independent genus, sister toScabiosa sect.Trochocephalus which then has to be treated as a genus,Lomelosia. In contrast, the following genera have to be included inLomelosia:Tremastelma asLomelosia sect.Callistemma, andScabiosiopsis as part ofLomelosia sect.Lomelosia. Pseudoscabiosa deviates in so many features that it has to be excluded from the redefinedScabioseae s. str.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00985103
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 37
    Electronic Resource
    Electronic Resource
    Allozyme differentiation in the Mediterranean firs (Abies, Pinaceae). A first comparative study with phylogenetic implications (1999)
    Springer
    Plant systematics and evolution 216 (1999), S. 289-307 
    Details
    ISSN: 1615-6110
    Keywords: Gymnosperms ; Pinaceae ; A. alba ; A. cephalonica ; A. borisii-regis ; A. bornmuelleriana ; A. nordmanniana ; A. equi-trojani ; A. pinsapo ; A. numidica ; A. cilicica ; Allozyme variation ; genetic diversity ; phylogenetic relationships ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nineteen natural Mediterranean fir populations, belonging to eight species and to one natural hybrid (A. ×borisii-regis), were investigated by starch and polyacrylamide gel electrophoresis. A total of 31 alleles was scored at eight loci (IDH-B, ACP-A, PER-B, 6PGD-A, 6PGD-B, MNR-B, PGI-B, PGM-A. Great variation was observed in the heterozygosity among the population studied and ranged from 0.010 (A. pinsapo) to 0.328 (A. cephalonica). The interpopulation genetic diversity was about 26% of the total genetic diversity. From the dendrogram, new phylogenetic relationships were revealed. High affinity was observed between the Calabrian fir population and the one from north-west Greece as well as betweenA. equi-trojani grown in Asia Minor and the southern Greek populations. Species specific alleles were found inA. cilicica. From the findings of the present work, a new hypothesis concerning the taxonomy, distribution and evolution ofAbies species in the Balkan Peninsula is supported.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01084404
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 38
    Electronic Resource
    Electronic Resource
    The flagellar apparatus structure inMicrospora (Chlorophyceae) confirms a close evolutionary relationship with unicellular green algae (1999)
    Springer
    Plant systematics and evolution 217 (1999), S. 11-30 
    Details
    ISSN: 1615-6110
    Keywords: Chlorococcales ; Microsporales ; Microspora ; Absolute configuration ; classification ; evolution ; flagellar apparatus ; ultrastructure ; zoospore
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The spatial configuration of the flagellar apparatus of the biflagellate zoospores of the green algal genusMicrospora is reconstructed by serial sectioning analysis using transmission electron microscopy. Along with the unequal length of the flagella, the most remarkable characteristics of the flagellar apparatus are: (1) the subapical emergence of the flagella (especially apparent with scanning electron microscopy); (2) the parallel orientation of the two basal bodies which are interconnected by a prominent one-piece distal connecting fiber; (3) the unique ultrastructure of the distal connecting fiber composed of a central tubular region which is bordered on both sides by a striated zone; (4) the different origin of the d-rootlets from their relative basal bodies; (5) the asymmetry of the papillar region which together with the subapical position of the basal bodies apparently cause the different paths of corresponding rootlets in the zoospore anterior; (6) the presence of single-membered d-rootlets and multi-membered s-rootlets resulting in a 7-1-7-1 cruciate microtubular root system which, through the different rootlet origin, does not exhibit a strict 180° rotational symmetry. It is speculated that the different basal body origin of the d-rootlets is correlated with the subapical implant of flagella. It is further hypothesized that in the course of evolution the ancestors ofMicrospora had a flagellar papilla that has migrated from a strictly apical position towards a subapical position. Simultaneously, ‘ancestral’ shift of flagella along the apical cell body periphery has taken place as can be concluded from the presence of an upper flagellum overlying a lower flagellum in the flagellar apparatus ofMicrospora. The basic features of the flagellar apparatus of theMicrospora zoospore resemble those of the coccoid green algal generaDictyochloris andBracteacoccus and also those of the flagellate green algal genusHeterochlamydomonas. This strengthens the general supposition thatMicrospora is evolutionarily closely related to taxa which were formerly classified in the traditionalChlorococcales.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00984919
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 39
    Electronic Resource
    Electronic Resource
    Retention of nutrients in river basins (1999)
    Springer
    Aquatic ecology 33 (1999), S. 29-40 
    Details
    ISSN: 1573-5125
    Keywords: denitrification ; nature restoration ; nitrogen ; phosphorus ; riparian areas ; sedimentation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In Denmark, as in many other European countries, the diffuse losses of nitrogen (N) and phosphorus (P) from the rural landscape are the major causes of surface water eutrophication and groundwater pollution. The export of total N and total P from the Gjern river basin amounted to 18.2 kg ha−1 and 0.63 kg P ha−1 during June 1994 to May 1995. Diffuse losses of N and P from agricultural areas were the main nutrient source in the river basin contributing 76% and 51%, respectively, of the total export. Investigations of nutrient cycling in the Gjern river basin have revealed the importance of permanent nutrient sinks (denitrification and overbank sedimentation) and temporary nutrient storage in watercourses. Temporary retention of N and P in the watercourses thus amounted to 7.2–16.1 g N m−2 yr−1 and 3.7–8.3 g P m−2 yr−1 during low-flow periods. Deposition of P on temporarily flooded riparian areas amounted from 0.16 to 6.50 g P m−2 during single irrigation and overbank flood events, whereas denitrification of nitrate amounted on average to 7.96 kg N yr−1 per running metre watercourse in a minerotrophic fen and 1.53 kg N yr−1 per linear metre watercourse in a wet meadow. On average, annual retention of N and P in 18 Danish shallow lakes amounted to 32.5 g N m−2 yr−1 and 0.30 g P m−2 yr−1, respectively, during the period 1989–1995. The results indicate that permanent nutrient sinks and temporary nutrient storage in river systems represent an important component of river basin nutrient budgets. Model estimates of the natural retention potential of the Gjern river basin revealed an increase from 38.8 to 81.4 tonnes yr−1 and that P-retention increased from −0.80 to 0.90 tonnes yr−1 following restoration of the water courses, riparian areas and a shallow lake. Catchment management measures such as nature restoration at the river basin scale can thus help to combat diffuse nutrient pollution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009947907811
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 40
    Electronic Resource
    Electronic Resource
    Variation in nutrient availability and plant species diversity across forb and graminoid zones of a Northern New England high salt marsh (1999)
    Springer
    Plant ecology 143 (1999), S. 219-228 
    Details
    ISSN: 1573-5052
    Keywords: mineralization ; nitrogen ; phosphorus ; salinity ; stress
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Plant zonation patterns across New England salt marshes have been investigated for years, but how nutrient availability differs between zones has received little attention. We investigated how N availability, P availability, and plant N status varied across Juncus gerardii, Spartina patens, and mixed forb zones of a Northern New England high salt marsh. We also investigated relationships between several edaphic factors and community production and diversity across the high marsh. P availability, soil salinity, and soil moisture were higher in the mixed forb zone than in the two graminoid zones. NH+ 4-N availability was highest in the J. gerardii zone, but NO− 3-N availability and mid season net N mineralization rates did not vary among zones. Plant tissue N concentrations were highest in the mixed forb zone and lowest in the S. patens zone, reflecting plant physiologies more so than soil N availability. Community production was highest in the J. gerardii zone and was positively correlated with N availability and negatively correlated with soil moisture. Plant species diversity was highest in the mixed forb zone and was positively correlated with P availability and soil salinity. Thus, nutrient availability, plant N status, and plant species diversity varied across zones of this high marsh. Further investigation is needed to ascertain if soil nutrient availability influences or is a result of the production and diversity differences that exist between vegetation zones of New England high salt marshes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009887727465
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 41
    Electronic Resource
    Electronic Resource
    Some personal reflections on the history of Bioeconomics (1999)
    Springer
    Journal of bioeconomics 1 (1999), S. 13-18 
    Details
    ISSN: 1573-6989
    Keywords: Malthus ; Darwin ; evolution ; policy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Economics
    Notes: Abstract This is a rather impressionist report of my recollections of the history of the bioeconomics field.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010001905194
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 42
    Electronic Resource
    Electronic Resource
    Bioeconomics as economics from a Darwinian perspective (1999)
    Springer
    Journal of bioeconomics 1 (1999), S. 19-34 
    Details
    ISSN: 1573-6989
    Keywords: Darwinian world view ; evolution ; evolutionary economics ; development ; subjectivism ; natural selection ; analogy ; adaptation ; evolutionary progress ; preferences ; genetic endowment ; growth of consumption
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Economics
    Notes: Abstract Bioeconomics—the merging of views from biology and economics—on the one hand invites the 'export' of situational logic and sophisticated optimization developed in economics into biology. On the other hand, human economic activity and its evolution, not least over the past few centuries, may be considered an instance for fruitfully applying ideas from evolutionary biology and Darwinian theory. The latter perspective is taken in the present paper. Three different aspects are discussed in detail. First, the Darwinian revolution provides an example of a paradigm shift which contrasts most significantly with the 'subjectivist revolution' that took place at about the same time in economics. Since many of the features of the paradigmatic change that were introduced into the sciences by Darwinism may be desirable for economics as well, the question is explored whether the Darwinian revolution can be a model for introducing a new paradigm in economic theory. Second, the success of Darwinism and its view of evolution have induced economists who are interested in an evolutionary approach in economics to borrow, more or less extensively, concepts and tools from Darwinian theory. Particularly prominent are constructions based on analogies to the theory of natural selection. Because several objections to such analogy constructions can be raised, generalization rather than analogy is advocated here as a research strategy. This means to search for abstract features which all evolutionary theories have in common. Third, the question of what a Darwinian world view might mean for assessing long term economic evolution is discussed. Such a view, it is argued, can provide a point of departure for reinterpreting the hedonistic approach to economic change and development. On the basis of such an interpretation bioeconomics may not only go beyond the optimization-cum-equilibrium paradigm currently prevailing in economics. It may also mean adding substantial qualifications to the subjectivism the neoclassical economists, at the turn of the century, were proud to establish in the course of their scientific revolution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1010054006102
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 43
    Electronic Resource
    Electronic Resource
    Fixing Content and Function in Neurobiological Systems: The Neuroethology of Electroreception (1999)
    Springer
    Biology and philosophy 14 (1999), S. 395-430 
    Details
    ISSN: 1572-8404
    Keywords: adaptationism ; Daniel C. Dennett ; electric fish ; electroreception ; evolution ; evolutionary function ; indeterminism ; mental content ; neuroethology ; sensory modality ; underdetermination
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract Are attributions of content and function determinate, or is there no fact of the matter to be fixed? Daniel Dennett has argued in favor of indeterminacy and concludes that, in practice, content and function cannot be fixed. The discovery of an electrical modality in vertebrates offers one concrete instance where attributions of function and content are supported by a strong scientific consensus. A century ago, electroreception was unimagined, whereas today it is widely believed that many species of bony fish, amphibians, sharks, skates, and rays possess this non-human sensory modality. A look at the history of science related to this discovery reveals a highly interdisciplinary endeavor, encompassing ethology, behavioral analysis, neuroscience, and evolutionary biology. While each area provides important evidence, none is sufficient on its own to fix content and function. Instead, I argue that an interdisciplinary, neuroethological approach is required to carry out such determinations. Further, a detailed consideration of biological research suggests that while content and function claims are empirically underdetermined and uncertain, there is insufficient reason to believe in an additional problem of indeterminism. In particular, Dennett's indeterminism arises from a research methodology -- logical adaptationism -- that generates evidence from only one of the areas of neuroethology. However, logical adaptationism does not reflect adaptationism as it is practiced in contemporary biology. I conclude that Dennett is faced with a dilemma: On the one hand, he can hold to logical adaptationism and the indeterminism that results from it, while giving up the relevance of his arguments to biological practice. On the other, he can embrace a more accurate version of adaptationism -- one which plays a role in a larger neuroethological framework -- but from which no strong indeterminacy claims follow.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006594531789
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 44
    Electronic Resource
    Electronic Resource
    Evolutionary Change and Epistemology (1999)
    Springer
    Biology and philosophy 14 (1999), S. 561-584 
    Details
    ISSN: 1572-8404
    Keywords: change ; evolution ; evolutionary epistemology ; selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract This paper is concerned with the debate in evolutionary epistemology about the nature of the evolutionary process at work in the development of science: whether it is Darwinian or Lamarckian. It is claimed that if we are to make progress through the many arguments that have grown up around this issue, we must return to an examination of the concepts of change and evolution, and examine the basic kinds of mechanism capable of bringing evolution about. This examination results in two kinds of processes being identified, dubbed ‘direct’ and ‘indirect’, and these are claimed to exhaust all possibilities. These ideas are then applied to a selection of the debates within evolutionary epistemology. It is shown that while arguments about the pattern and rate of evolutionary change are necessarily inconclusive, those concerning the origin of novel variations and the mode of inheritance can be resolved by means of the distinctions made here. It is claimed that the process of selection in the evolution of science can also be clarified. The conclusion is that the main process producing the evolution of science is a direct or Lamarckian one although, if realism is correct, an indirect or Darwinian process plays a vital role.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006568200814
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 45
    Electronic Resource
    Electronic Resource
    Preadaptation and the Explanation of Human Evolution (1999)
    Springer
    Biology and philosophy 14 (1999), S. 65-82 
    Details
    ISSN: 1572-8404
    Keywords: adaptation ; explanation ; evolution ; preadaptation ; specialization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract The concept of preadaptation, though useful, continues to trouble evolutionary scientists. Usually, it is treated as if it were really adaptation, prompting such diverse theorists as Gould and Vrba, and Dennett to suggest its removal from evolutionary theory altogether. In this paper, I argue that the as-if sense is ill-founded, and that the sense of preadaptation as a process may be defended as unequivocal and generally useful in evolutionary explanations, even in such problem areas as human evolution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006539827648
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 46
    Electronic Resource
    Electronic Resource
    Modus Darwin (1999)
    Springer
    Biology and philosophy 14 (1999), S. 253-278 
    Details
    ISSN: 1572-8404
    Keywords: ancestry ; Bayesianism ; creationism ; Darwin ; evolution ; likelihood ; natural selection ; phylogeny ; probability ; Reichenbach
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract Modus Darwin is a principle of inference that licenses the conclusion that two species have a common ancestor, based on the observation that they are similar. The present paper investigates the principle's probabilistic foundations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006626115852
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 47
    Electronic Resource
    Electronic Resource
    Retelling Experiments: H.B.D. Kettlewell's Studies of Industrial Melanism in Peppered Moths (1999)
    Springer
    Biology and philosophy 14 (1999), S. 39-54 
    Details
    ISSN: 1572-8404
    Keywords: experiment ; evolution ; industrial melanism ; natural selection
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Philosophy
    Notes: Abstract H. B. D. Kettlewell's field experiments on industrial melanism in the peppered moth, Biston betularia, have become the best known demonstration of natural selection in action. I argue that textbook accounts routinely portray this research as an example of controlled experimentation, even though this is historically misleading. I examine how idealized accounts of Kettlewell's research have been used by professional biologists and biology teachers. I also respond to some criticisms of David Rudge to my earlier discussions of this case study, and I question Rudge's claims about the importance of purely observational studies for the eventual acceptance and popularization of Kettlewell's explanation for the evolution of industrial melanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006576518561
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 48
    Electronic Resource
    Electronic Resource
    Protein Kinase C Targeting in Antineoplastic Treatment Strategies (1999)
    Springer
    Investigational new drugs 17 (1999), S. 227-240 
    Details
    ISSN: 1573-0646
    Keywords: apoptosis ; protein kinase C ; sphingoid bases ; safingol ; diglyceride ; bryostatin 1 ; staurosporine ; 7-hydroxy staurosporine (UCN-01) ; 4′-N-benzoyl staurosporine (CGP-41251) ; calphostin C (UCN-1028c)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Neoplastic cell survival is governed by a balance between pro-apoptotic and anti-apoptotic signals. Noteworthy among several anti-apoptotic signaling elements is the protein kinase C (PKC) isoenzyme family, which mediates a central cytoprotective effect in the regulation of cell survival. Activation of PKC, and subsequent recruitment of numerous downstream elements such as the mitogen-activated protein kinase (MAPK) cascade, opposes initiation of the apoptotic cell death program by diverse cytotoxic stimuli. The understanding that the lethal actions of numerous antineoplastic agents are, in many instances, antagonized by cytoprotective signaling systems has been an important stimulus for the development of novel antineoplastic strategies. In this regard, inhibition of PKC, which has been shown to initiate apoptosis in a variety of malignant cell types, has recently been the focus of intense interest. Furthermore, there is accumulating evidence that selective targeting of PKC may prove useful in improving the therapeutic efficacy of established antineoplastic agents. Such chemosensitizing strategies can involve either (a) direct inhibition of PKC (e.g., following acute treatment with relatively specific inhibitors such as the synthetic sphingoid base analog safingol, or the novel staurosporine derivatives UCN-01 and CGP-41251) or (b) down-regulation (e.g., following chronic treatment with the non-tumor-promoting PKC activator bryostatin 1). In preclinical model systems, suppression of the cytoprotective function(s) of PKC potentiates the activity of cytotoxic agents (e.g., cytarabine) as well as ionizing radiation, and efforts to translate these findings into the clinical arena in humans are currently underway. Although the PKC-driven cytoprotective signaling systems affected by these treatments have not been definitively characterized, interference with PKC activity has been associated with loss of the mitogen-activated protein kinase (MAPK) response. Accordingly, recent pre-clinical studies have demonstrated that pharmacological disruption of the primary MEK-ERK module can mimic the chemopotentiating and radiopotentiating actions of PKC inhibition and/or down-regulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006328303451
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 49
    Electronic Resource
    Electronic Resource
    Activation-Induced Apoptosis of Peripheral Lymphocytes Treated with 7-Hydroxystaurosporine, UCN-01 (1999)
    Springer
    Investigational new drugs 17 (1999), S. 335-341 
    Details
    ISSN: 1573-0646
    Keywords: UCN-01 ; IL-2 receptor ; Fas ; Fas-ligand ; apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract 7-hydroxystaurosporine (UCN-01) is a new anticancer agentwhich exerts an inhibitory effect on cell cycle check points andis currently under phase I clinical trials in US and Japan.Preliminary clinical data indicated that UCN-01 remained inplasma at high concentrations for long periods of time. Thisunavoidable high plasma drug exposure is likely to lead tohematological toxicities in patients. In the present study,cultured human peripheral blood lymphocytes (PBLs) were used toevaluate the possible hematological toxicities of UCN-01treatment. UCN-01 induces apoptosis, and the induction ofapoptosis-related surface markers were also examined toinvestigate the involvement of these molecules in UCN-01-inducedapoptosis in PBLs. in vitroviability of PBLs wasdecreased by high dose of UCN-01 (25 μM, 3-day exposure). Thiseffect of UCN-01 was significantly suppressed by the presence ofhuman serum, suggesting that some specific inhibitory factor(s)in human serum may antagonize the lympholytic effect of UCN-01.The percentage of annexin V-positive PI-negative cells increasedwith exposure to UCN-01 in a time- and dose-dependent manner; byup to 30.3% after exposure to 25 μM UCN-01 for 3 days.At the same time, the expression of both interleukin-2 receptor(IL-2R, CD25) and Fas (CD95), analyzed by flow cytometry, wasinduced. Con A-stimulated PBLs were more sensitive toUCN-01-induced apoptosis than non-stimulated lymphocytes andUCN-01 increased the sFas-L released into culture medium from conA-stimulated PBLs. Therefore, lymphocyte depletion mediated byactivation-induced apoptosis is likely to occur in patientstreated with UCN-01 at high doses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006374118879
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 50
    Electronic Resource
    Electronic Resource
    Influence of bcl-2 on antibody productivity in high cell density perfusion cultures of hybridoma (1999)
    Springer
    Cytotechnology 30 (1999), S. 95-106 
    Details
    ISSN: 1573-0778
    Keywords: apoptosis ; Bcl-2 ; fixed-bed ; hollow fibre ; hybridoma ; perfusion ; protein-free medium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Apoptosis is an active, genetically determined death mechanism which can be induced by a wide range of physiological factors and by mild stress. It is the predominant form of cell death during the production of antibodies from murine hybridoma cell lines. A number of studies have now demonstrated that the suppression of this death pathway, by means of over-expression of survival genes such as bcl-2, results in improved cellular robustness and antibody productivity during batch culture. In the present study, the influence of bcl-2 expression on hybridoma productivity in two high density perfusion bioreactor systems was investigated. In the first system, a fixed-bed reactor, the DNA content in the spent medium was 25% higher in the control (TB/C3-pEF) culture than that found in the bcl-2 transfected (TB/C3-bcl2) cultures at all perfusion rates. This is indicative of a higher level of cell death in the control cell line. The average antibody concentration for the TB/C3-pEF cell line was 14.9 mg L-1 at perfusion rates of 2.6 and 5.2 d-1. However, for the TB/C3-bcl2 cell line it was 33 mg L-1 at dilution rates of 2 and 4 d-1. A substantial increase in antibody concentration was also found in the Integra Tecnomouse hollow fibre reactor. The antibody titre in the TB/C3-bcl2 cassette was nearly 100% higher than that in the TB/C3-pEF cassette during the cultivation period which lasted 6 weeks. Clearly, these results demonstrate the positive impact of bcl-2 over-expression on production of antibody in hybridoma perfusion cultures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008055702079
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 51
    Electronic Resource
    Electronic Resource
    Effect of meteorology and nutrient load on oxygen depletion in a Danish micro-tidal estuary (1999)
    Springer
    Aquatic ecology 33 (1999), S. 55-64 
    Details
    ISSN: 1573-5125
    Keywords: estuaries ; nitrogen ; oxygen depletion ; phosphorus ; regression model ; vertical mixing
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In a detailed analysis of oxygen saturation in a shallow Danish estuary it was possible to separate the effect of meteorological forcings (i.e. wind and solar radiation) and nutrient loads on oxygen depletion in bottom water. Regression analysis showed that oxygen saturation tied to nitrogen load rather than to phosphorus load. During summer periods of stratification the oxygen saturation could be attributed to the time elapsed after the onset of stratification and the accumulated nitrogen loading 10 month prior to measurement. Using a 10-year meteorological database and an empirical model it was calculated that a 25% reduction in nitrogen loading would reduce the number of days with severe oxygen depletion (i.e. 〈15% of saturation) by more than 50%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009956210537
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 52
    Electronic Resource
    Electronic Resource
    Co-expression of bcl-2 and bag-1, apoptosis suppressing genes, prolonged viable culture period of hybridoma and enhanced antibody production (1999)
    Springer
    Cytotechnology 31 (1999), S. 143-151 
    Details
    ISSN: 1573-0778
    Keywords: antibody productivity ; apoptosis ; BAG-1 ; Bcl-2 ; cell survival ; hybridoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Human bcl-2 and bag-1 DNA were introduced into mouse hybridoma 2E3- O cells and expressed. The expression of bcl-2 in BCMGneo-bcl2 transfectants was confirmed by ELISA and that of bag-1 in pZeo-bag1 was confirmed by western blotting. In batch cultures, the over-expression of bcl-2 prolonged the culture period by 2 days and co-expression of bcl-2 and bag-1 prolonged the culture period by 3 days. The delayed increase in the dead cell number in culture of the bcl-2 and bag-1 cotransfectant indicated the additional antiapoptosis effect of bcl-2 and bag-1 cotransfection in comparison with the bcl-2 only transfection. The bcl-2 transfectants (2E3O-Bcl2) produced antibody twofold per batch culture in comparison with 2E3-O cells transfected with BCMGSneo (2E3O-Mock). Enhancement of this MoAb production was due to the improved survival of the cells and was not due to stimulation of antibody production rate per cell by Bcl-2 expression. And the bcl-2 and bag-1 co-transfectant (2E3O-Bcl2-BAG1) produced antibody approximately fourfold of 2E3O-Mock per batch culture. Enhancement of this MoAb production was due to the improved survival of the cells and was partly due to stimulation of MoAb production rate per cell in the non-growing phase by the cotransfection. The method to engineer hybridoma cells genetically with bcl-2 and bag-1 for increasing viability and productivity would be widely applied for improving antibody productivity of hybridoma cultures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008080407581
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 53
    Electronic Resource
    Electronic Resource
    A novel 96-well scintillation proximity assay for the measurement of apoptosis (1999)
    Springer
    Cytotechnology 31 (1999), S. 271-282 
    Details
    ISSN: 1573-0778
    Keywords: annexin V ; Apo-2 ligand ; apoptosis ; Cytostar-T® scintillating microplates ; flow cytometry ; lymphotoxin (LT)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The translocation of phospholipids across the plasma membrane has been widely documented as one of the earliest measurable biochemical events of apoptosis. Using fluorescently labelled annexin V, which preferentially binds phosphatidylserine (PS) in the presence of Ca2+, the externalization of PS can be measured and apoptosis quantified using flow cytometry. Conventional detection methods utilizing annexin V, while faster than in situ DNA end-labelling or DNA laddering, require extensive sample preparation which may compromise samples and makes rapid, high volume screening prohibitive. This paper describes a novel assay for the measurement of apoptosis based upon binding of radiolabelled annexin V to apoptotic cells attached to the growth surface of a 96-well scintillating microplate (Cytostar-T®). We compared measurements of apoptosis made by flow cytometry to those obtained with the scintillating microplate in three model systems, treatment of: mouse connective tissue (L-M) cells with lymphotoxin (LT), human lung carcinoma (H460) cells with Apo-2 ligand and human umbilical vein endothelial (HUVE) cells with staurosporine. In this assay, we compare both direct and indirect labelling methods by utilizing either iodinated annexin V or biotinylated annexin V/[35S] streptavidin to radiolabel apoptotic cells. The signal detected is a direct consequence of the binding of annexin V to externalized PS on apoptotic cells and the proximity of the label to the base of the plate. Using this method, separation of bound and unbound radiolabel signal occurs directly within the well resulting in a sensitive assay that requires minimal manipulation and can accomodate a large number of samples.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008053320396
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 54
    Electronic Resource
    Electronic Resource
    A Model for the Dynamic Interaction Between Evolution and Learning (1999)
    Springer
    Neural processing letters 10 (1999), S. 181-193 
    Details
    ISSN: 1573-773X
    Keywords: evolution ; learning ; ontogeny ; neural development ; structure optimization
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract The interaction between learning and evolution has elicited much interest particularly among researchers who use evolutionary algorithms for the optimization of neural structures. In this article, we will propose an extension of the existing models by including a developmental phase – a growth process – of the neural network. In this way, we are able to examine the dynamical interaction between genetic information and information learned during development. Several measures are proposed to quantitatively examine the benefits and the effects of such an overlap between learning and evolution. The proposed model, which is based on the recursive encoding method for structure optimization of neural networks, is applied to the problem domain of time series prediction. Furthermore, comments are made on problem domains which associate growing networks (size) during development with problems of increasing complexity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018724306675
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 55
    Electronic Resource
    Electronic Resource
    Effects of Potato-cyst Nematodes (Globodera pallida) and Soil pH on Root Growth, Nutrient Uptake and Crop Growth of Potato (1999)
    Springer
    European journal of plant pathology 105 (1999), S. 61-76 
    Details
    ISSN: 1573-8469
    Keywords: core sampling ; foliar nutrient concentrations ; minirhizotrons ; nitrogen ; phosphorus ; potassium ; Rhizolab
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Potato-cyst nematodes (Globodera pallida) cause severe yield losses in potato. Plants infected with potato-cyst nematodes generally have reduced concentrations of nitrogen, phosphorus and potassium in the foliage. This study investigated whether reduced growth of nematode-infected potato is caused by nutrient limitation. Experiments in the field and in containers showed that phosphorus concentration correlated best with total crop biomass at early stages of growth. The role of phosphorus in nematode damage was further investigated in the field and in the Wageningen Rhizolab. The experimental field was infested with potato-cyst nematodes and two levels of nematode density were established by fumigation with a nematicide. Prior applications of calcium carbonate resulted in pHKCl levels of 4.8 and 6.1. Two levels of phosphorus fertiliser were applied: either 0 or 225 kg P ha−1. In the Wageningen Rhizolab, soil of both pH levels from the field was used after treatment with 1 MRad gamma irradiation to kill the nematodes. Subsequently, half of the soil was inoculated with cysts to give a nematode density of 30 viable juveniles per gram of soil. In the field, nine weeks after planting, the total crop biomass ranged from 107 g m−2 for the treatment with nematodes at pHKCl 6.1 without phosphorus fertiliser to 289 g m−2 for the fumigated treatment at pHKCl 4.8 with phosphorus fertiliser. The differences in total biomass for the various treatments were explained by differences in foliar phosphorus concentration. Nematodes induced or aggravated P deficiency and reduced total biomass. This was not the only damage mechanism as at high, non-limiting levels of foliar phosphorus concentration, nematodes still reduced total biomass. In the Wageningen Rhizolab, directly after planting, the number of roots visible against minirhizotrons was reduced by nematodes. However, the increase of root number in the nematode treatment continued longer than in the control, until root number was higher than that of the control. The compensary root growth of the nematode treatment was restricted to the top 30 cm and nematodes reduced rooting depth. High soil pH reduced growth, mainly by reducing the availability of phosphate. Both nematodes and high soil pH reduced nutrient uptake per unit root length. Our results lead us to suggest an interaction between nematodes and soil pH, with nematode damage being higher at pHKCl 6.1 than at pHKCl 4.8.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008641511688
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 56
    Electronic Resource
    Electronic Resource
    The Histidine Decarboxylase (HDC) Gene of Tetrahymena Pyriformis is Similar to the Mammalian One. A Study of HDC Expression (1999)
    Springer
    Bioscience reports 19 (1999), S. 73-79 
    Details
    ISSN: 1573-4935
    Keywords: Histidine decarboxylase ; Tetrahymena ; gene sequencing ; evolution ; histamine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract RNA was isolated from Tetrahymena pyriformis GL and using human histidine decarboxylase (HDC) gene primers, the RT-PCR product was sequenced. A fraction containing 207 base pairs was compared to the published sequences of prokaryotic and mammalian (rat, mouse and human) HDC cDNA (exons). The HDC-cDNA fraction of Tetrahymena was similar to the mammalian cDNA-s and it was completely different from the prokaryotic HDC-gene. The results indicate the presence of a mammalian-like HDC-gene already in a unicellular eukaryote organism and demonstrates also that the divergence of the prokaryotic–eukaryotic common gene took place already at this low evolutionary level.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1020102308791
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 57
    Electronic Resource
    Electronic Resource
    Verotoxin/Globotriaosyl Ceramide Recognition: Angiopathy, Angiogenesis and Antineoplasia (1999)
    Springer
    Bioscience reports 19 (1999), S. 345-354 
    Details
    ISSN: 1573-4935
    Keywords: Glycolipid ; apoptosis ; intracellular traffic ; multidrug resistance ; ovarian carcinoma ; astrocytoma ; post transplant lymphoproliferative disease ; bone marrow purging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Verotoxin (VT) is involved in the etiology of both hemorrhagic colitis and the hemolytic uremic syndrome which are microvasculopathies of the colon and pediatric renal glomerulus respectively. Thus, VT can be considered a vasotoxin. Cell sensitivity in vitro varies according to the receptor glycolipid (globotriaosyl ceramide-Gb3) expression and also to intracellular trafficking of the receptor/toxin complex, such that in highly sensitive cells, the toxin is targeted to the endoplasmic reticulum and nuclear envelope. Such cells include tumor cells which have become drug resistant. Thus Gb3 is upregulated in certain tumors and when such tumor cells become drug resistant, their sensitivity to verotoxin increases. This may be due to a direct role of the MDR1 drug efflux pump in glycolipid biosynthesis. In addition to the tumor tissue, the toxin receptor may also be expressed in the tumor neovasculature suggesting that activated endothelial cells may be verotoxin sensitive. Thus VT may have both a direct and indirect antineoplastic potential. VT has proved highly effective in a xenograft cancer model and the possible therapeutic use of VT is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1020299819637
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 58
    Electronic Resource
    Electronic Resource
    Ceramide Glycanase Activities in Human Cancer Cells (1999)
    Springer
    Bioscience reports 19 (1999), S. 449-460 
    Details
    ISSN: 1573-4935
    Keywords: ceramide glycanase ; cancer cells ; glycosphingolipid ; sphingosine ; ceramide ; apoptosis ; PPMP ; PDMP
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract Ceramide glycanase (CGase) activities have been detected in different human tumor cells (colon, carcinoma Colo-205; neuroblastoma, IMR-32; breast cancer lines, SKBr3 and MCF7). However, the level of enzymatic activity is lower in these cells compared to that present in other mammalian tissues reported before (Basu, M., Kelly, P., Girzadas, M. A., Li, Z., and Basu, S. Methods Enzymol. (in press)). The majority of CGase activity was found in the 100,000g soluble supernatant fraction isolated from all these cell lines and tissues. Using the soluble enzyme, the requirement for optimum CGase activity was found to be consistent with previous observations found for rat and rabbit tissues (Basu, M., Dastgheib, S., Girzadas, M. A., O'Donnell, P. H., Westervelt, C. W., Li, Z., Inokuchi, J. I., and Basu, S. (1998) Acta Pol. Biochim. 42:327). The CGase activities from both Colo-205 and IMR-32 cells are optimum at a protein to detergent ratio of one. All the mammalian CGases, including human cancer cells, show an optimum pH between 5.5 and 5.8 in sodium acetate buffer. The CGase activities from cancer cells are found to be cation-independent; however, mercury, zinc, and copper ions seem to inhibit the enzyme activity substantially in both tumor cells lines. The mercury ion inhibition of CGase activities from all different sources indicates a possible structural homology in the CGase proteins. Radiolabeled substrates, labeled at the sphingosine double bond or at the 3-position of sphingosine without modifying double bond of sphingosine were used in this investigation. Both were active substrates with all enzyme preparations isolated from different cancer cells (apparent Km, 500 μM for nLcOse5[3H-DT]Cer and 350 μM for GgOse4[sph-3-3H]Cer with Colo-205 enzyme). Structural analogues of ceramide and sphingosine (L-PPMP, L-PDMP, alkylamines, and Tamoxifen) inhibited cancer cell CGase activities in vitro.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1020220524180
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 59
    Electronic Resource
    Electronic Resource
    Adenosine-induced cell death: evidence for receptor-mediated signalling (1999)
    Springer
    Apoptosis 4 (1999), S. 197-211 
    Details
    ISSN: 1573-675X
    Keywords: Adenosine ; apoptosis ; necrosis ; physiopathological implications.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Adenosine modulates the proliferation, survival and apoptosis of many different cell types, ranging from epithelial, endothelial and smooth muscle cells, to cells of the immune and neural lineages. In this review, we critically discuss the available in vitro and in vivo data which support a role for adenosine in both development-associated apoptosis, and in diseases characterized by either pathologically increased cell death (e.g., ischemia, trauma and aging-associated neurodegeneration) or abnormally reduced spontaneous apoptosis (e.g., cancer). Particular emphasis is given to the possible role of extracellular adenosine receptors, since these may represent novel and attractive molecular targets for the pharmacological modulation of apoptosis. In some instances, adenosine-induced cell death has been demonstrated to require entry of the nucleoside inside cells; however, in many other cases, activation of specific adenosine extracellular receptors has been demonstrated. Of the four G protein-coupled adenosine receptors so far identified, the A2A and the A3 receptors have been specifically implicated in modulation of cell death. For the A3 receptor, results obtained by exposing both cardiomyocytes and brain astrocytes to graded concentrations of selective agonists suggest induction of both cell protection and cell death. Such opposite effects, which likely depend on the degree of receptor activation, may have important therapeutic implications in the pharmacological modulation of cardiac and brain ischemia. For the A2A receptor, recent intriguing data suggest a specific role in immune cell death and immunosuppression, which may be relevant to both adenosine-deaminase-immunodeficiency syndrome (a pathology characterized by accumulation of adenosine to toxic levels) and in tumors where induction of apoptosis via activation of specific extracellular receptors may be desirable. Finally, preliminary data suggest that, in a similar way to the adenosine-deaminase-immunodeficiency syndrome, the abnormal accumulation of adenosine in degenerative muscular diseases may contribute to muscle cell death. Although the role of adenosine receptors in this effect still remains to be determined, these data suggest that adenosine-induced apoptosis may also represent a novel pathogenic pathway in muscular dystrophies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009666707307
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 60
    Electronic Resource
    Electronic Resource
    Apoptin®-induced apoptosis: a review (1999)
    Springer
    Apoptosis 4 (1999), S. 317-319 
    Details
    ISSN: 1573-675X
    Keywords: Anti-tumor therapy ; Apoptin® ; apoptosis ; Bcl-2 ; p53.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Apoptin, a protein encoded by an avian virus, induces apoptosis in various cultured human tumorigenic and/ or transformed cell lines, e.g. derived from breast and lung tumor, leukemia, lymphoma, osteosarcoma melanoma, cholangiocarcinoma, and hepatoma. In such cells, Apoptin induces p53-independent apoptosis, and the proto-oncogene Bcl-2 can accelerate this effect. The latter is surprising for, in general, Bcl-2 is known to inhibit e.g., p53-induced apoptosis. On the other hand, in normal non-transformed human cells, Apoptin is unable to induce apoptosis, even when Bcl-2 is over-expressed. In animal models Apoptin-induced apoptosis appears to be a safe and efficient anti-tumor agent. These data, in continuation with the observations that Apoptin is specifically stimulated by Bcl-2 in tumor cells, does not need p53, and is not inhibited by Bcr-Abl in these cells, imply that Apoptin is a potential anti-tumor therapy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009687019221
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 61
    Electronic Resource
    Electronic Resource
    Apoptosis in ventricular myocytes: the role of tumor suppressor proteins (1999)
    Springer
    Apoptosis 4 (1999), S. 229-234 
    Details
    ISSN: 1573-675X
    Keywords: Adenovirus ; apoptosis ; Bcl-2 ; p53 ; Rb ; ventricular myocytes.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Apoptosis or programmed cell death is an important physiologic event crucial for the selective removal of damaged or unwanted cells from body tissues. In the cardiovascular system, apoptosis has been observed in the vasculature and myocardium. Untimely or inappropriate myocardial cell loss through an apoptotic process may contribute to ventricular remodeling and the ultimate demise of ventricular function following injury. Therapeutic interventions designed to modulate or prevent myocardial apoptotic cell loss may therefore prove beneficial in maintaining cardiac function. Incite into the molecular mechanisms that govern apoptosis in mammalian cells has led to the identification of several key factors that promote or prevent the apoptotic process. In this report, we discuss putative regulators of cardiac cell apoptosis with specific reference to the tumor suppressor proteins, p53 and Rb. The interplay between these factors, as well as the anti-apoptotic molecules related to the Bcl-2 the family are discussed in the context of the heart under normal and disease conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009640124029
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 62
    Electronic Resource
    Electronic Resource
    Tau protein is involved in the apoptotic process induced by anti-microtubule agents on neuroblastoma cells (1999)
    Springer
    Apoptosis 4 (1999), S. 47-58 
    Details
    ISSN: 1573-675X
    Keywords: Anti-microtubule agents ; apoptosis ; doxorubicin ; neuroblastoma ; tau ; taxoid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Paclitaxel and docetaxel are potent anti-microtubule and antimitotic agents that induce apoptosis in bone marrow-derived cells and epithelial cells. This study examined apoptosis induced by anti-microtubule agents in the neuroblastoma SK-N-SH cell line with a special focus on tau protein which is one of the main Microtubule-Associated- Proteins (MAPs) in neuronal cells. In time, treatment with 1 μM paclitaxel successively induced formation of bundles, then pseudo-asters concomitantly with mitotic block and phosphorylation of bcl-2 (48 h), then phosphorylation of tau and externalization of phosphatidylserine at the early phase of apoptosis (72 h) and finally DNA fragmentation (96 h). Similar results were obtained with 0.5 μM vinorelbine. Paclitaxel induced a lower increase in tau phosphorylation in differentiated SK-N-SH/RA+ cells which are less sensitive to apoptosis. Moreover, doxorubicin whose mechanism of action is independent of microtubules also induced immunostaining of tau at 72 h treatment. In conclusion, our results on neuroblastoma cells show that overexpression of hyperphosphorylated tau is involved in the apoptotic process induced by anti-microtubule agents and may be extended to others cytostatic drugs. Thus, tau protein may play a role in the cellular events observed in neuroblastoma cells undergoing apoptosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009682116158
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 63
    Electronic Resource
    Electronic Resource
    IL-3 induces apoptosis in a ras-transformed myeloid cell line (1999)
    Springer
    Apoptosis 4 (1999), S. 71-80 
    Details
    ISSN: 1573-675X
    Keywords: abl ; apoptosis ; interleukin-3 ; oncogenes ; ras.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Growth factors promote cell survival and proliferation. Homeostasis is maintained by programmed cell death which occurs when the growth stimulus is withdrawn, in response to negative growth regulators such as interferons, TNF-α and CD95 ligand, or following differentiation. Although acutely-transforming oncogenes often overcome the need for growth factors, growth regulatory cytokines can influence proliferative responses of transformed cells. In this study we investigated the effects of IL-3 on the proliferative responses of parental bone marrow-derived 32D cells and cells transformed with ras and abl oncogenes. We show that treatment of ras-transformed 32D cells with IL-3 reduced proliferative responses and decreased colony-forming ability. These effects were exacerbated in the absence of serum and associated with inhibition of tyrosine kinase activity, down-regulation of RAS and MYC expression, and induction of apoptosis as indicated by DNA fragmentation. In contrast, treatment of parental 32D cells with IL-3, which is obligatory for cell survival and proliferation, increased tyrosine kinase activity, upregulated MYC and RAS expression and maintained DNA integrity. With abl-transformed cells, proliferation and colony-forming ability were also inhibited by IL-3. Tyrosine kinase activity and MYC expression were reduced, but early apoptosis was not evident. Calcium uptake however, was stimulated by IL-3 in both parental and oncogene-transformed cells. These results suggest that threshold levels of tyrosine kinase activity are necessary for cell survival and proliferation and that with ras-transformed cells, IL-3 treatment may result in this threshold being breached. We conclude that in some situations, growth-promoting cytokines can inhibit proliferation of transformed cells and induce cell death by apoptosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009686220607
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 64
    Electronic Resource
    Electronic Resource
    Retrotransposon 1731 in Drosophila melanogaster changes retrovirus-like expression strategy in host genome (1999)
    Springer
    Genetica 107 (1999), S. 73-77 
    Details
    ISSN: 1573-6857
    Keywords: D. melanogaster ; evolution ; frameshifting ; retrotransposon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Earlier related to parasitic elements, retrotransposons of eukaryotes have been demonstrated to participate in general cell processes such as chromosome repair and evolution of gene expression (Teng et al., 1996; McDonald, 1993). Here, we report the existence of two class of genomic copies of retrotransposon 1731 with different expression strategies, one of which might be driven by natural selection. The first class uses conventional translation frameshifting known to ensure expression of revere transcriptase (RT) open reading frame (ORF), depending on the efficiency of frameshifting. The bulk of genomic copies are related to the second class where the frameshift is prevented as a result of the substitution of a rare codon recoginsing rare tRNA by a codon preferred by host genome, whereas the RT ORF is restored by downstream single nuclotide deletion. We suggest that natural selection has driven the switching of 1731 expression strategy from retrovirus-like to the fussion-ORF expression. This observation is in accordance with the detection in testes of fused Gag-RT polypetide encoded by 1731. The abundance of RT in testes may serve for normal development of host tissue.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003969625694
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 65
    Electronic Resource
    Electronic Resource
    Ameloblast apoptosis and IGF-1 receptor expression in the continuously erupting rat incisor model (1999)
    Springer
    Apoptosis 4 (1999), S. 441-447 
    Details
    ISSN: 1573-675X
    Keywords: ameloblasts ; amelogenesis ; apoptosis ; insulin-like growth factor.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Enamel-producing cells (ameloblasts) pass through several phenotypic and functional stages during enamel formation. In the transition between secretory and maturation stages, about one quarter of the ameloblasts suddenly undergo apoptosis. We have studied this phenomenon using the continuously erupting rat incisor model. A special feature of this model is that all stages of ameloblast differentiation are presented within a single longitudinal section of the developing tooth. This permits investigation of the temporal sequence of gene and growth factor receptor expression during ameloblast differentiation and apoptosis. We describe the light and electron microscopic morphology of ameloblast apoptosis and the pattern of insulin-like growth factor-1 receptor expression by ameloblasts in the continuously erupting rat incisor model. In the developing rat incisor, ameloblast apoptosis is associated with downregulated expression of the insulin-like growth factor-1 receptor. These data are consistent with the hypothesis that ameloblasts are “hard wired” for apoptosis and that insulin-like growth factor-1 receptor expression is required to block the default apoptotic pathway. Possible mechanisms of insulin-like growth factor-1 inhibition of ameloblast apoptosis are presented. The rat incisor model may be useful in studies of physiological apoptosis as it presents apoptosis in a predictable pattern in adult tissues.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009600409421
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 66
    Electronic Resource
    Electronic Resource
    Apoptotic cell death and related gene expression in metastatic tumors of AKR lymphomas of varying malignancy (1999)
    Springer
    Apoptosis 4 (1999), S. 429-440 
    Details
    ISSN: 1573-675X
    Keywords: AKR lymphoma malignancy variants ; apoptosis ; apoptosis-related gene expression ; tumor progression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Resistance to apoptosis may be related to tumor progression, due to the implications it might have on both tumor mass and genetic instability. We compared the tendency to spontaneous apoptosis and the proliferative capacity of metastatic growths of several AKR lymphoma variants (TAU-45, TAU-47, TAU-44, TAU-33, TAU-42 and TAU-46, in the order of increasing metastatic potential). We further compared the expression of several apoptosis-related genes. Cell proliferative capacity did not appear to determine malignant behavior since, on the whole, a decrease in S + G2M fraction was observed with increasing malignancy. Sensitivity to apoptotic cell death decreased with increasing malignancy when comparing the TAU-45, TAU-47, TAU-44 and TAU-33 variants, suggesting a role of reduced apoptosis in this T-cell lymphoma. An increase in Bcl-2 content with increasing aggressiveness among these variants, implicates this protein in this tumor progression-related resistance to apoptosis. However, the two variants of highest malignancy, TAU-42 and TAU-46, did not follow the same trend, since they displayed a relatively high content in apoptotic cells and a low Bcl-2 content. Fas receptor expression did not correlate with tendency to apoptosis, indicating that malignant behavior in the AKR lymphoma does not depend on CD95/Fas/APO1 downregulation. Overexpression of p53 was observed only in one of the variants of lowest malignancy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009648325350
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 67
    Electronic Resource
    Electronic Resource
    Signalling steps in apoptosis by ether lipids (1999)
    Springer
    Apoptosis 4 (1999), S. 419-427 
    Details
    ISSN: 1573-675X
    Keywords: Anti-oxidant defence ; apoptosis ; ether lipids ; glutathione ; ionising radiation ; stress.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We have investigated the mechanisms of induction of apoptosis by the antineoplastic ether lipid ET-18-OCH3 (ALP) in sensitive S49wt mouse lymphoma cells and ALP-resistant S49ar variants, both with wild-type p53, and in related L1210 cells with mutated p53. Ether lipid-resistant S49ar cells were cross-resistant to extracellular stress factors (cold shock, heat shock, H2O2, dimethylsulfoxide) and to radiation-induced apoptosis but not to physiological apoptotic signals (dexamethasone, growth factor deprivation, thapsigargin, C2-ceramide) and expressed similar levels of the apoptosis-regulating proteins Bcl-2, Bcl-X, Bax, Bad and Bak as did the parent S49wt cells. The uptake of [3H]-ALP was strongly reduced in the stress-resistant cells but this was not associated with significant differences in membrane cholesterol:phospholipid content nor in membrane microviscosity. In S49ar cells the activity of the antioxidant enzyme glutathione peroxidase (GSH-Px) was increased 4-fold and depletion of glutathione with the drug L-buthionine-S-R-sulfoximine (L-BSO) lowered the resistance of S49ar cells to ALP, stress factors and ionising radiation. The results indicate that ether lipids induce apoptosis by imposing a special form of physico-chemical stress, mediated by reactive oxygen species but independent of p53 status. The capacity of glutathione-dependent anti-oxidant defence appeared an important and shared determinant of the sensitivity to ether lipids, several types of extracellular stress and ionising radiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009644208512
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 68
    Electronic Resource
    Electronic Resource
    Sequential occurrence of mitochondrial and plasma membrane alterations, fluctuations in cellular Ca2+ and pH during initial and later phases of cell death (1999)
    Springer
    Apoptosis 4 (1999), S. 455-460 
    Details
    ISSN: 1573-675X
    Keywords: Annexin V ; apoptosis ; flow cytometry ; intracellular Ca2+ ; intracellular pH ; mitochondrial membrane potential.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The sequential occurrence of plasma and mitochondrial membrane alterations, intra-cellular pH shifts and changes in intracellular Ca2+ concentration after induction of cell death was monitored by flow cytometry in Jurkat and HSB2-cells. Cell death was induced by treatment with anti-Fas antibodies or by irradiation. Phosphatidylserine (PS) exposure and plasma membrane integrity were measured with FITC-Annexin V adhesion and by Propidium Iodide exclusion. Transition of the mitochondrial membrane potential was monitored by the occurrence of decay of DiOC6 fluorescence. Intracellular pH shifts were monitored by changes in the ratio of fluorescence at 575 nm and at 635 nm of SNARF-1-AM. Fluctuations in intracellular Ca2+ concentration were established by changes in Fura red quenching. The Jurkat cells were sensitive to anti-Fas treatment, while HSB-2 cells were not. HSB-2 cells appeared more sensitive to radiation damage than Jurkat cells. In all experiments the transition of mitochondrial membrane potential occurred first, almost immediately followed by PS exposure. Fluctuations in intracellular Ca2+ concentration occurred later and were less outspoken. A decrease in intracellular pH occurred not earlier than 24 hours after anti-Fas treatment. Chelation of intracellular Ca2+ concentration with BAPTA-AM had no effect on the time sequence of cell death related events.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1009604510329
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 69
    Electronic Resource
    Electronic Resource
    The globalization of N deposition: ecosystem consequences in tropical environments (1999)
    Springer
    Biogeochemistry 46 (1999), S. 67-83 
    Details
    ISSN: 1573-515X
    Keywords: acidification ; anthropogenic nitrogen ; cations ; nitrate leaching ; nitric oxide ; nitrous oxide ; nutrient limitation ; phosphorus ; productivity ; tropical ecosystems
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Human activities have more than doubled the inputs of nitrogen (N) into terrestrial systems globally. The sources and distribution of anthropogenic N, including N fertilization and N fixed during fossil fuel combustion, are rapidly shifting from the temperate zone to a more global distribution. The consequences of anthropogenic N deposition for ecosystem processes and N losses have been studied primarily in N-limited ecosystems in the temperate zone; there is reason to expect that tropical ecosystems, where plant growth is most often limited by some other resource, will respond differently to increasing deposition. In this paper, we assess the likely direct and indirect effects of increasing anthropogenic N inputs on tropical ecosytem processes. We conclude that anthropogenic inputs of N into tropical forests are unlikely to increase productivity and may even decrease it due to indirect effects on acidity and the availability of phosphorus and cations. We also suggest that the direct effects of anthropogenic N deposition on N cycling processes will lead to increased fluxes at the soilwater and soil-air interfaces, with little or no lag in response time. Finally, we discuss the uncertainties inherent in this analysis, and outline future research that is needed to address those uncertainties.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01007574
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 70
    Electronic Resource
    Electronic Resource
    Ecosystem constraints to symbiotic nitrogen fixers: A simple model and its implications (1999)
    Springer
    Biogeochemistry 46 (1999), S. 179-202 
    Details
    ISSN: 1573-515X
    Keywords: carbon dioxide ; grazing ; nitrogen fixation ; nitrogen limitation ; phosphorus ; shade
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract The widespread occurrence ofN limitation to net primary production (NPP) and other ecosystem processes, despite the ubiquitous occurrence ofN-fixing symbioses, remains a significant puzzle in terrestrial ecology. We describe a simple simulation model for an ecosystem containing a generic nonfixer and a symbioticN fixer, based on: (1) a higher cost forN acquisition byN fixers than nonfixers; (2) growth of fixers and fixation ofN only when lowN availability limits the growth of nonfixers, and other resources are available; and (3) losses of fixedN from the system only when the quantity of availableN exceeds plant and microbial demands. Despite the disadvantages faced by theN fixer under these conditions,N fixation and loss adjustN availability close to the availability of other resources, and biomass and NPP in this simple model can be substantially but only transientlyN limited. We then modify the model by adding: (1) losses ofN in forms other than excess availableN (e.g., dissolved organicN, trace gases produced by nitrification); and (2) constraints to the growth and activity ofN fixers imposed by differential effects of shading,P limitation, and grazing. The combination of these processes is sufficient to describe an open system, with input from both precipitation andN fixation, that is nevertheless stronglyN-limited at equilibrium. This model is useful for exploring causes and consequences of constraints toN fixation, and hence ofN limitation, and we believe it will also be useful for evaluating howN fixation and limitation interact with elevatedCO 2 and other components of global enviromental change.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01007579
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 71
    Electronic Resource
    Electronic Resource
    The impact of accelerating land-use change on the N-Cycle of tropical aquatic ecosystems: Current conditions and projected changes (1999)
    Springer
    Biogeochemistry 46 (1999), S. 109-148 
    Details
    ISSN: 1573-515X
    Keywords: estuaries ; lakes ; marine ; nitrogen ; phosphorus ; rivers ; streams ; temperate ; tropics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Published data and analyses from temperate and tropical aquatic systems are used to summarize knowledge about the potential impact of land-use alteration on the nitrogen biogeochemistry of tropical aquatic ecosystems, identify important patterns and recommend key needs for research. The tropical N-cycle is traced from pre-disturbance conditions through the phases of disturbance, highlighting major differences between tropical and temperate systems that might influence development strategies in the tropics. Analyses suggest that tropical freshwaters are more frequently N-limited than temperate zones, while tropical marine systems may show more frequent P limitation. These analyses indicate that disturbances to pristine tropical lands will lead to greatly increased primary production in freshwaters and large changes in tropical freshwater communities. Increased freshwater nutrient flux will also lead to an expansion of the high production, N- and light-limited zones around river deltas, a switch from P- to N-limitation in calcareous marine systems, with large changes in the community composition of fragile mangrove and reef systems. Key information gaps are highlighted, including data on mechanisms of nutrient transport and atmospheric deposition in the tropics, nutrient and material retention capacities of tropical impoundments, and N/P coupling and stoichiometric impacts of nutrient supplies on tropical aquatic communities. The current base of biogeochemical data suggests that alterations in the N-cycle will have greater impacts on tropical aquatic ecosystems than those already observed in the temperate zone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006156213761
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 72
    Electronic Resource
    Electronic Resource
    Pharmacodynamics and Toxicodynamics of Drug Action: Signaling in Cell Survival and Cell Death (1999)
    Springer
    Pharmaceutical research 16 (1999), S. 790-798 
    Details
    ISSN: 1573-904X
    Keywords: MAPK ; caspases ; chemopreventive agents ; phase II drug metabolizing enzymes ; apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In therapeutic response to drugs, the plasma concentration range leads to the establishment of a safe and effective dosage regimen. Our hypothesis is that by studying drug concentration-dependent effect on signal transduction mechanisms, a better understanding of the beneficial pharmacodynamic and adverse toxicodynamic responses elicited by the drug may be achieved. Using two classes of chemopreventive compounds (phenolic antioxidants and isothiocyanates), we illustrate the potential utility of two signal transduction pathways elicited by these agents to predict the pharmacodynamic effect (induction of Phase II drug metabolizing enzymes) and the potential toxicodynamic response (stimulation of caspase activity and cytotoxic cell death). At lower concentration, phenolic antioxidants and isothiocyanates activate mitogen-activated protein kinase (MAPK; extracellular signal-regulated protein kinase 2, ERK2; and c-Jun N-terminal kinase 1, JNK1) in a concentration-and time-dependent manner. The activation of MAPK by these compounds may lead to the induction of cell survival/protection genes such as c-jun, c-fos, or Phase II drug metabolizing enzymes. However, at higher concentrations, these agents activate another signaling molecule, ICE/Ced3 cysteine protease enzymes (caspases) leading to apoptotic cell death. The activation of these pathways may dictate the fate of the cells/tissues upon exposure to drugs or chemicals. At lower concentrations, these compounds activate MAPK leading to the induction of Phase II genes, which may protect the cells/tissues against toxic insults and therefore may enhance cell survival. On the other hand, at higher concentrations, these agents may activate the caspases, which may lead to apoptotic cell death, and have toxicity. Understanding the activation of these and other signal transduction events elicited by various drugs and chemicals may yield insights into the regulation of gene expression of drug metabolizing enzymes and cytotoxicity. Thus, the study of signaling events in cell survival (hemeostasis) and cell death (cytotoxicity) may have practical application during pharmaceutical drug development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1011953431486
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 73
    Electronic Resource
    Electronic Resource
    The limits of phosphorus removal in wetlands (1999)
    Springer
    Wetlands ecology and management 7 (1999), S. 165-175 
    Details
    ISSN: 1572-9834
    Keywords: flow ; loading ; models ; phosphorus ; removal limits ; wetlands
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The phosphorus concentrations exported from wetlands are explored via data and a first order model. The graph of outlet concentration versus areal phosphorus loading is used to display these data and the model. For a given wetland, data and models show that P concentrations show an ‘S’ curve response to increasing P loadings. The lower plateau is the background concentration and the upper plateau is the inlet concentration. The position of the ascending limb between the two plateaus is positioned differently for different wetlands. Phosphorus (P) removal in wetlands is often typified by a stable decreasing gradient of P concentrations from inlet to outlet, and an accompanying stable decreasing gradient in P assimilation. Limits to removal are inherent in the physical, chemical and biological processes. A lower outlet concentration limit exists because of the P cycle in the un-impacted wetland. The loading at which the outlet concentration departs from background, the lower knee in the loading curve, varies from wetland to wetland. An upper outlet concentration limit is imposed by the source concentration for extremely high inflows. The first order mass balance equation interpolates between these limits. The model gives further insights about performance within an overall envelope. The water carrying capacity of the wetland precludes flows in excess of the hydraulic conveyance capacity, thus limiting the possible P loadings to the system. Conversely, extremely low hydraulic loadings cause the wetland to be dominated by atmospheric additions and losses. The central tendency of inter-system data in the North American Database is shown to be inadequate to draw generalized conclusions about ecosystem processes in an individual wetland. The proposed ‘one gram rule’ of Richardson, et al. (1997) is shown to be an over-simplification.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008415401082
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 74
    Electronic Resource
    Electronic Resource
    Allozyme variation in relation to morphology and taxonomy inMedicago sect.Spirocarpos subsect.Intertextae (Fabaceae) (1999)
    Springer
    Plant systematics and evolution 214 (1999), S. 29-47 
    Details
    ISSN: 1615-6110
    Keywords: Fabaceae ; Medicago ; Systematics ; evolution ; allozymes ; isozymes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Medicago intertexta andM. ciliaris have been controversially recognized as separate species. The only reliable diagnostic character, gland-tipped trichomes on the fruits inM. ciliaris, is controlled by presence of a single dominant allele, and such one-character taxonomies are debatable. Contributing to the difficulty,M. muricoleptis andM. granadensis, the other two species ofMedicago sectionSpirocarpos subsectionIntertextae, are sometimes confusingly similar toM. intertexta or to each other. Allozyme differences provided 95% verification of the suitability of the gland-tipped trichome character for separatingM. intertexta andM. ciliaris, thus corroborating their recognition as separate taxa. Several measures of allozyme variation indicated thatM. intertexta is more polymorphic than its sister species. Heterozygosity was also highest inM. intertexta, suggestive of a higher outcrossing rate, which is also consistent with larger floral size. Heterozygosity ofM. intertexta was concentrated in Sicily and nearby countries. Taxonomic difficulties in identifying SicilianM. intertexta are well known, and may be the result of interspecific hybridization and introgression.Medicago muricoleptis differed from the above two species in the frequency of several alleles, whileM. granadensis possessed numerous unique alleles consistent with its complete absence of genetic exchange with the other three substantially interfertile species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00985730
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 75
    Electronic Resource
    Electronic Resource
    The bicolor unit — homology and transformation of an inflorescence structure unique to coreMalvales (1999)
    Springer
    Plant systematics and evolution 214 (1999), S. 187-198 
    Details
    ISSN: 1615-6110
    Keywords: Malvales ; Sterculiaceae ; Tiliaceae ; Bombacaceae ; Malvaceae ; Inflorescence morphology ; epicalyx ; systematics ; homology ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A broad comparative analysis reveals that the inflorescences of coreMalvales, familiesSterculiaceae, Tiliaceae, Bombacaceae andMalvaceae, include characteristic repeating units. The basic repeating unit is called bicolor unit (afterTheobroma bicolor, where it was first observed). It is determinate and bears three bracts, one of which is invariably sterile, whereas the others subtend lateral cymes or single flowers. Through the demonstration of intermediate steps in closely related taxa the triad of bracts within a bicolor unit and the trimerous malvalean epicalyx are shown to be homologous. Various possibilities for an origin of the bicolor unit are discussed. Bicolor units are variously arranged to form complete inflorescences. In many taxa they are terminal on modules that comprise two (or fewer) prophylls. These modules may be arranged in elongated anthocladia or condensed sympodia, which in turn may constitute components of higher order inflorescence structures. The presence of the bicolor unit or its derivatives linksSterculiaceae, Tiliaceae, Bombacaceae andMalvaceae. It is absent from all other families included in a broader defined orderMalvales and represents one of the rare morphological synapomorphies of coreMalvales. Furthermore, inflorescence morphology provides characters of systematic significance for various taxa within coreMalvales.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00985738
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 76
    Electronic Resource
    Electronic Resource
    Genetic variation and putative hybridization inSalix alba andS. fragilis (Salicaceae): Evidence from allozyme data (1999)
    Springer
    Plant systematics and evolution 215 (1999), S. 169-187 
    Details
    ISSN: 1615-6110
    Keywords: Salicaceae ; Salix alba ; S. fragilis ; Allozymes ; clones ; population structure ; hybridization ; polyploidy ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Genetic variability was estimated by enzyme electrophoresis in 239 Belgian clones from theSalix alba-S. fragilis complex. This morphological complex suggested a high frequency of hybrids. To test this hypothesis, the clones were pooled as a single co-adapted species complex and secondly as belonging to either species, i.e. beingS. alba-like orS. fragilis-like. The standard genetic variability measures showed higher values for the complex than for the separate species. However, the observed mean heterozygosity was lower in the putative hybrid complex than for each of the species separately. The fixation indices were more variable at the species level and indicated that mostS. fragilis locations appeared fixed forlap-1, whereas no fixation occured inS. alba locations. Averaged at the regional (i.e. catchment) level, this difference between the two species remained and values ranged from 0.457 to 0.617 inS. alba and were much higher, fixed homozygous or monomorph inS. fragilis. Hierarchical F-statistics revealed that most of the differentiation occured at the lower levels of localities and tributaries and that there was no further differentiation between catchments. Tributaries which are 10–25km in length were proposed as the most likely entities for further examination of putative hybridization and events of allelic fixations. By considering the two abovementioned approaches of data input, it could be suggested that most of the allozyme differentiation was between the species and less between the regions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00984654
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 77
    Electronic Resource
    Electronic Resource
    Phylogenetic study on wild allies of Lima bean,Phaseolus lunatus (Fabaceae), and implications on its origin (1999)
    Springer
    Plant systematics and evolution 218 (1999), S. 43-54 
    Details
    ISSN: 1615-6110
    Keywords: Fabaceae ; Phaseolus ; Phaseolus lunatus ; Taxonomy ; germplasm ; evolution ; origin ; allozyme ; Latin America
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract An investigation was made of the phylogenetic relationships among wild accessions of Lima bean (Phaseolus lunatus) and wild allies of Mesoamerican and Andean origins, using electrophoresis of seed storage proteins and isozymes. Mesoamerican wild species are phylogenetically more distant fromP. lunatus than Andean species, and apparently belong to the tertiary gene pool of Lima bean. The Andean wild species, which are investigated for the first time, reveal a high similarity to the Lima bean, and particularly with its Mesoamerican gene pool. These Andean species probably constitute a secondary gene pool of Lima bean, and are thus of considerable interest in the context of genetic improvement of the crop. Based on these observations, an Andean origin is suggested for the Andean wild species and forP. lunatus. These results point out the importance of collecting and conserving AndeanPhaseolus germplasm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01087033
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 78
    Electronic Resource
    Electronic Resource
    Floral scent chemistry and pollination ecology in phytelephantoid palms (Arecaceae) (1999)
    Springer
    Plant systematics and evolution 217 (1999), S. 279-297 
    Details
    ISSN: 1615-6110
    Keywords: Arecaceae ; Phytelephantoideae ; Aleocharinae ; Baridinae ; Derelomini ; Mystrops ; Xanthopygus ; Brood-site pollination ; dioecy ; evolution ; floral scents ; flower-breeding ; pollination ; thermogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The subfamilyPhytelephantoideae comprises three genera (Ammandra, Aphandra, andPhytelephas) and seven species of dioecious palms. The floral scents ofAmmandra dasyneura, A. decasperma, Aphandra natalia, Phytelephas aequatorialis, P. macrocarpa, andP. seemannii were analyzed by gas chromatography-mass spectrometry. We studied the pollination biology ofA. natalia, P. aequatorialis, andP. macrocarpa, and tested how the synthetically produced main constituents of the floral scents ofAphandra andPhytelephas attracted insects in two natural populations ofPhytelephas. The genera are distinct in terms of floral scents.Ammandra has sesquiterpenes,Aphandra (+)-2-methoxy-3-sec-butylpyrazine, andPhytelephas p-methyl anisol. These constituents dominated the scents quantitatively and qualitatively. The similarity between scents of male and female inflorescences was 76.5% inAmmandra, 84.2% inAphandra, and 〉99% inPhytelephas. Different species ofAleocharinae (Staphylinidae) pollinateAphandra natalia andPhytelephas species and reproduce in their male inflorescences.Derelomini (Curculinoidae) andMystrops (Nitidulidae) only visit and pollinatePhytelephas in which male inflorescences they reproduce. A species ofBaridinae (Curculionidae) only visits and pollinatesAphandra natalia, and reproduces in its female inflorescence. The apparent reliance on one or a few floral scent constituents as attractants and few and specific pollinators may indicate co-evolution. Sympatric species ofPhytelephantoideae have different scents. We suggest that species with similar scents have allopatric distributions due to the absence of a pollinator isolation mechanism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00984371
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 79
    Electronic Resource
    Electronic Resource
    A monophyletic origin of the B chromosomes ofBrachycome dichromosomatica (Asteraceae) (1999)
    Springer
    Plant systematics and evolution 219 (1999), S. 127-135 
    Details
    ISSN: 1615-6110
    Keywords: Asteraceae ; Brachycome ; B chromosome ; polymorphism ; evolution ; karyotyping ; centromere
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The A and B chromosomes of different karyotype variants (cytodemes A1, A2, A3 and A4) ofBrachycome dichromosomatica were analysed by computer-aided chromosome image analysis and fluorescencein situ hybridisation (FISH). Ribosomal DNA and the B chromosome-specific sequence Bd49 were detected on all B chromosomes. In addition to minor size variation of the Bs, polymorphism of the rDNA and Bd49 position and copy number revealed two major types of B chromosomes. The B chromosomes of all the cytodemes were indistinguishable from each other in length, but that of A3 showed evidence of rearrangements consistent with its long-term geographic isolation. The results presented suggest a monophyletic origin of the B chromosomes ofB. dichromosomatica.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01090304
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 80
    Electronic Resource
    Electronic Resource
    Phylogenetic relationships of the enigmatic fern families Hymenophyllopsidaceae and Lophosoriaceae: Evidence fromrbcL nucleotide sequences (1999)
    Springer
    Plant systematics and evolution 219 (1999), S. 263-270 
    Details
    ISSN: 1615-6110
    Keywords: Hymenophyllopsis ; Lophosoria ; molecular systematics ; evolution ; rbcL ; phylogeny
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Nucleotide sequences fromrbcL were used to infer relationships of Lophosoriaceae and Hymenophyllopsidaceae. The phylogenetic positions of these two monotypic fern families have been debated, and neither group had been included in recent molecular systematic studies of ferns. Maximum parsimony analysis of our data supported a sister relationship betweenLophosoria andDicksonia, and also betweenHymenophyllopsis andCyathea. Thus, both newly-examined families appear to be part of a previously characterized and well-supported clade of tree ferns. The inferred relationships ofLophosoria are consistent with most (but not all) recent treatments. However,Hymenophyllopsis includes only small delicate plants superficially similar to filmy ferns (Hymenophyllaceae), very different from the large arborescent taxa. Nevertheless, some synapomorphic characteristics are shared with the tree fern clade. Further studies on gametophytes ofHymenophyllopsis are needed to test these hypotheses of relationship.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00985583
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 81
    Electronic Resource
    Electronic Resource
    Effects of phosphorus nutrition on tiller emergence in wheat (1999)
    Springer
    Plant and soil 209 (1999), S. 283-295 
    Details
    ISSN: 1573-5036
    Keywords: leaf emergence ; phosphorus ; photosynthesis ; tillering ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Phosphorus (P) deficiency limits the yield of wheat, particularly by reducing the number of ears per unit of area because of a poor tiller emergence. The objectives of this work were to (i) determine whether tiller emergence under low phosphorus availability is a function of the availability of assimilates for growth or a direct result of low P availability, (ii) attempt to establish a quantitative relation between an index of the availability of P in the plant and the effects of P deficiency on tiller emergence, and (iii) to provide a better understanding of the mechanisms involved in tiller emergence in field-grown wheat. Wheat (Triticum aestivum L., cv. INTA Oasis), was grown in the field under drip irrigation on a typic Argiudol, low in P (5.5 μg P g-1 soil Bray & Kurtz I) in Balcarce, Argentina. Treatments consisted of the combination of three levels of P fertilization 0, 60 and 200 kg P2O5 ha-1, and two levels of assimilate availability, a control (non-shaded) and 65% of reduction in incident irradiance from seedling emergence until the end of tillering (shaded). Phosphorus treatments significantly modified the pattern of growth and development of the plants. Shading reduced the growth and concentration of water-soluble carbohydrates in leaves and stems. Leaf photosynthetic rate at saturating irradiance was reduced by P deficiency, but was not affected by shading. At shoot P concentrations less than 4.2 g P kg-1 the heterogeneity in the plant population increased with respect to the number of plants bearing a certain tiller. At a shoot P concentration of 1.7 g P kg-1 tillering ceased completely. Phosphorus deficiency directly altered the normal pattern of tiller emergence by slowing the emergence of leaves on the main stem (i.e. increasing the phyllochron), and by reducing the maximum rate of tiller emergence for each tiller.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004690404870
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 82
    Electronic Resource
    Electronic Resource
    The effect of regeneration burns on the growth, nutrient acquisition and mycorrhizae of Eucalyptus regnans F. Muell. (mountain ash) seedlings (1999)
    Springer
    Plant and soil 210 (1999), S. 273-283 
    Details
    ISSN: 1573-5036
    Keywords: ectomycorrhizae ; Eucalyptus regnans ; forest burns ; nitrogen ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract This study was conducted to compare the effects on the growth of Eucalyptus regnans seedlings of unheated soil and soil heated to different extents (as indicated by soil colour–bright red or black) in burnt logging coupes, and to separate the effects of heating of the soil on direct nutrient availability and on morphotypes and effectiveness of ectomycorrhizae. Burnt soils were collected from three logging coupes burnt 2, 14 and 25 months previously and unbumt soil from adjacent regrowth forests. Compared to unburnt soil, the early seedling growth was stimulated in black burnt soil from all coupes (burnt 2, 14 and 25 months previously). Seedling growth was generally poor in red burnt soil, especially in soil collected 2 months after burning. However, the concentration of extractable P was extremely high in red burnt soil, especially in soil collected 2 months after burning. In black burnt soil, extractable P was increased in soil 2 months after burning, but not in the soils collected 14 or 25 months after burning. However, both total P content and concentration in seedlings were increased in all collections of black burnt soil. Frequency of ectomycorrhizae was high in seedlings grown in all black burnt soils, but the mycorrhizal mantles were poorly developed in seedlings in black burnt soil collected 2 months after burning. Seedlings were also ectomycorrhizal in red burnt soil, except in soil collected 2 months after burning. Fine root inocula from seedlings grown in black burnt soils collected 14 and 25 months after burning significantly stimulated both seedling growth and P uptake compared with the uninoculated control, whereas the fine root inocula from the seedlings grown in all the other soils did not. These results suggest that, in black burnt soil, both direct nutritional changes and changes in the ectomycorrhizae may contribute to seedling growth promotion after regeneration burns. The generally poor seedling growth in red burnt soils is likely to have been due to N deficiency as the seedlings in these soils were yellow-green and the tissue concentrations of N were significantly lower than in other treatments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004609912315
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 83
    Electronic Resource
    Electronic Resource
    Evidence for functional convergence of redox regulation in G6PDH isoforms of cyanobacteria and higher plants (1999)
    Springer
    Plant molecular biology 40 (1999), S. 487-494 
    Details
    ISSN: 1573-5028
    Keywords: cysteine positions ; evolution ; gene duplication ; glucose-6-phosphate dehydrogenase ; isoform classes ; redox regulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract In a recent paper (Wenderoth et al., J Biol Chem 272: 26985–26990, 1997) we reported that the positions of the two redox regulatory cysteines identified in a plastidic G6PD isoform from potato (Solanum tuberosum L.) differ substantially from those conserved in cyanobacterial G6PDH sequences. To investigate the origin of redox regulation in G6PDH enzymes from photoautotrophic organisms, we isolated and characterized several G6PD cDNA sequences from higher plants and from a green and a red alga. Alignments of the deduced amino acid sequences showed that the cysteine residues cluster in the coenzyme-binding domain of the plastidic isoforms and are conserved at three out of six positions. Comparison of the mature proteins and the signal peptides revealed that two different plastidic G6PDH classes (P1 and P2) evolved from a common ancestral gene. The two algal sequences branch off prior to this class separation in higher plants, sharing about similar amino acid identity with either of the two plastidic G6PDH classes. The genes for cytosolic plant isoforms clearly share a common ancestor with animal and fungal G6PDH homologues, whereas the cyanobacterial isoforms branch within the eubacterial G6PDH sequences. The data suggest that cysteine-mediated redox regulation arose independently in G6PDH isoenzymes of eubacterial and eukaryotic lineages.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006257230779
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 84
    Electronic Resource
    Electronic Resource
    Persistence of tree related patterns in soil nutrients following slash-and-burn disturbance in the tropics (1999)
    Springer
    Plant and soil 209 (1999), S. 137-157 
    Details
    ISSN: 1573-5036
    Keywords: fire ; nitrogen ; phosphorus ; soil nutrient heterogeneity ; tree effects ; tropical dry forest
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Individual trees are known to influence soil chemical properties, creating spatial patterns that vary with distance from the stem. The influence of trees on soil chemical properties is commonly viewed as the agronomic basis for low-input agroforestry and shifting cultivation practices, and as an important source of spatial heterogeneity in forest soils. Few studies, however, have examined the persistence of the effects of trees on soil after the pathways responsible for the effects are removed. Here, we present evidence from a Mexican dry forest indicating that stem-related patterns of soil nutrients do persist following slash-and-burn removal of trees and two years of cropping. Pre-disturbance concentrations of resin extractable phosphorus (P), bicarbonate extractable P, NaOH extractable P, total P, total nitrogen (N) and carbon (C), KCl extractable nitrate (NO3 -), and net N mineralization and nitrification rates were higher in stem than dripline soils under two canopy dominant species of large-stemmed trees with contrasting morphologies and phenologies (Caesalpinia eriostachys Benth. and Forchhammeria pallida Liebm.). These stem effects persisted through slash burning and a first growing season for labile inorganic and organic P, NaOH inorganic P, and plant-available P, and through a second growing season for labile organic P, NaOH organic P, and plant-available P. While stem effects for extractable NO3 -, net nitrification rates, total N and C disappeared after felling and slash burning, these stem effects returned after the first growing season. These results support the view that tree-influenced patterns of soil nutrients do persist after tree death, and that trees contribute to the long-term spatial heterogeneity of forest soils.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004503023973
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 85
    Electronic Resource
    Electronic Resource
    Nitrogen and phosphorus requirement of the microbiota in soils of the Bornhöved Lake district (1999)
    Springer
    Plant and soil 212 (1999), S. 173-181 
    Details
    ISSN: 1573-5036
    Keywords: nitrogen ; phosphatase activity ; phosphorus ; protease activity ; soil microbial biomass ; substrate-induced respiration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Estimating in situ N and P status of the soil microbiota is complicated because microbiological features reflect potentials rather than field conditions. Complementary microbiological assays were, therefore, combined to evaluate the N and P requirement of the microbiota in seven agricultural, grassland and forest topsoils of the Bornhöved Lake district as follows: (i) the sensitivity of the substrate-induced respiration (SIR) to supplemental addition of N and P was monitored during microbial growth and (ii) soil protease and phosphatase activities were analysed and related to soil mass and microbial biomass content. Nitrogen addition increased the maximal SIR rate in all except one soil indicating that the growth of organisms is restricted by this element when easily degradable C source is present. Supplemental N (and in some cases also P) retarded the respiratory response within the first 24 h which suggests microbial sensitivity and/or greater anabolic efficiency. With additional N the maximal SIR rate was most strongly enhanced in topsoils of the beech forest and the dystric alder forest. Thus, the microbial growth in these soils that were below litter horizons seems to be mostly restricted by N. Supplemental P positively affected respiratory response of soils under monoculture, wet grassland and dystric alder forest. In the dystric alder forest soil, high rates of alkaline and unbuffered phosphatase activity were observed when activity was related to either soil mass or microbial biomass content. The data of proteolytic and phospholytic enzymes are discussed with reference to nutrient deficiency and microbial strategy for N and P adsorption.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004677427165
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 86
    Electronic Resource
    Electronic Resource
    Root-induced modifications of the exchange of phosphate ion between soil solution and soil solid phase (1999)
    Springer
    Plant and soil 211 (1999), S. 103-110 
    Details
    ISSN: 1573-5036
    Keywords: bioavailability ; isotopic evaluation ; phosphate ion exchange ; phosphorus ; rhizosphere ; soil solution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The uptake of phosphorus (P) by roots results in a depletion of phosphate ions (PO4) in the rhizosphere. The corresponding decrease in PO4 concentration in the soil solution (CP) gives rise to a replenishment of P from the solid phase which is time- and CP-dependent. This PO4 exchange which reflects the buffer power of the soil for PO4 also varies with the composition and the physico-chemical conditions of the soil. As root activity can modify these physico-chemical conditions in the rhizosphere, the question arises whether these modifications affect the ability of PO4 bound to the soil solid phase to exchange with PO4 in soil solution. The aim of the present work was to measure and compare the parameters which describe the amount of PO4 bound to soil solid phase that is capable to replenish solution P for both rhizosphere and bulk soils. The soil sample was a P-enriched, calcareous topsoil collected from a long-term fertiliser trial. Rhizosphere soil samples were obtained by growing dense mats of roots at the surface of 3 mm thick soil layer for one week. Three plant species were compared: oilseed rape (Brassica napus L., cv Goeland) pea (Pisum sativum L., cv. Solara) and maize ( Zea mays L., cv. Volga). The time- and CP-dependence of the PO4 exchange from soil to solution were described using an isotopic dilution method. The measured CP values were 0.165 mg P L−1 for bulk soil and 0.111, 0.101 and 0.081 mg P L−1 for rhizosphere soils of maize, pea and rape, respectively. The kinetics of the PO4 exchange between liquid and solid phases of soil were significantly different between rhizosphere and bulk soils. However, when changes in CP were accounted for, the parameters describing the PO4 exchange with time and CP between soil solution and soil solid phase were found to be very close for bulk and rhizosphere soils. For this calcareous and P-enriched soil, plant species differed in their ability to deplete PO4 in solution. The resulting changes in the ability of the soil solid phase to replenish solution PO4 were almost fully explained by the depletion of soil solution P.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004485432261
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 87
    Electronic Resource
    Electronic Resource
    Effect of ethrel on apoptosis in carrot protoplasts (1999)
    Springer
    Plant growth regulation 27 (1999), S. 119-123 
    Details
    ISSN: 1573-5087
    Keywords: apoptosis ; carrot protoplast ; DNA ladder ; ethrel ; ethylene ; nucleus condensation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract In recent years, apoptosis has been reported to exist in plants during normal development and in response to stress. However, little is known about the relation of hormones to this form of programmed cell death. Here, we report examination of characteristics of apoptosis in carrot protoplasts induced by ethylene evolved from ethrel (2-chloroethylphosphonic acid). Nucleus condensation and DNA ladders were observed, and neutral comet assay, which detects DNA cleavage, also provided evidence that ethrel treatment resulted in nuclear DNA fragmentation. Strikingly, a close correlation between the incidence of DNA comets and the percentage of apoptotic protoplasts was shown in ethrel-treated carrot protoplasts. In conclusion, this study demonstrated that ethylene is an active inducer of apoptosis in carrot protoplasts, and that ethylene-induced plant cell death showed characteristics similar to those of apoptosis in animals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006105101813
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 88
    Electronic Resource
    Electronic Resource
    Phylogeny of Vicia Subgenus Vicia (Fabaceae) Based on Analysis of RAPDs and RFLP of PCR-Amplified Chloroplast Genes (1999)
    Springer
    Genetic resources and crop evolution 46 (1999), S. 149-161 
    Details
    ISSN: 1573-5109
    Keywords: evolution ; genetic resources ; PCR-RFLP ; RAPDs ; Vicia ; taxonomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract We report the results of two methods of DNA analysis to elucidate phylogenetic relationships among 29 Vicia subgen. Vicia species in comparison with two species of subgenus Vicilla sect. Vicilla. The methods employed were RAPD analysis of total genomic DNA and PCR-RFLP analysis of five chloroplast genes, rbcL, rpoB, 16S, psaA and trnK. The results of each method were similar and complementary, and support the current taxonomic systems of subsp. Vicia. According to RAPD and PCR-RFLP analysis the Narbonensis complex can be considered a well separated section, which may be related to section Vicia. Sections Vicia, Atossa and Wiggersia are separate, but closely related sections. Species of the section Hypechusa form a single monophyletic section, where V. lutea, V. anatolica and V. hyrcanica are quite remote from other species. Our results suggest that within the subgenus Vicia, V. faba is more closely related to V. bithynica and that these two species are most closely related to section Peregrinae. We found that PCR-RFLP of cp DNA provided more precise information concerning relationships between Vicia sections than RAPD analysis. However, RAPD analysis was more informative concerning diversity of closely related Vicia taxa, such as the variable groups, section Narbonensis and V. sativa aggregate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008640322198
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 89
    Electronic Resource
    Electronic Resource
    Cytogenetic relationships between Avena insularis (2n=28) and both A. strigosa (2n=14) and A. murphyi (2n=28) (1999)
    Springer
    Genetic resources and crop evolution 46 (1999), S. 501-504 
    Details
    ISSN: 1573-5109
    Keywords: cytogenetics ; evolution ; interspecific hybrids ; oat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The newly discovered tetraploid oat Avena insularis was crossed with the diploid A. strigosa and the tetraploid A. murphyi. Considerably reduced chromosome association at meiosis and a low average number of chiasmata per cell of the A. strigosa × A. insularis hybrids indicated that the diploid A. strigosa did not participate in the creation of A. insularis. From A. murphyi, A. insularis differed by four chromosomal rearrangements and the hybrids between them were sterile. The tetraploids A. magna, A. murphyi and A. insularis share the two to four floret large diaspore, which is adapted to heavy alluvial soil. They all, however, diverge from one another by four chromosomal rearrangements. At this point it is not possible to determine whether they have diverged from a single tetraploid progenitor, or developed from different diploid species.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008728316354
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 90
    Electronic Resource
    Electronic Resource
    Conservation and innovation in spiralian development (1999)
    Springer
    Hydrobiologia 402 (1999), S. 255-265 
    Details
    ISSN: 1573-5117
    Keywords: evolution ; spiral cleavage ; Spiralia ; cell lineage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract It is clear that the spiralian developmental program represents a highly flexible platform for the generation of diverse larval and adult body plans. The widespread occurrence of this pattern of early development attests to its tremendous evolutionary success. Despite the large degree of conservation in the spiral cleavage pattern and other basic aspects of early development, changes in cell fate maps and in the mechanisms of blastomere specification have arisen. While we have learned a great deal about this mode of development, a number of important questions remain to be answered. To what extent do these conditions apply to the lesser studied spiralian phyla? What constraints have led to the preservation of the early spiral cleavage program? How has this developmental program been adapted for the construction of the various spiralian body plans (e.g. the segmental body plans of annelids or to the potential secondary loss of segmentation)? Are most changes associated with the elaboration of these different larval and adult body plans restricted to the late period of development? What molecular/genetic processes underlie this developmental program? Clearly, the spiralian phyla represent an important group of organisms for further studies on development and evolution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003756912738
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 91
    Electronic Resource
    Electronic Resource
    Qualitative and quantitative investigations of phytoplankton in Lake Ringsjön, Scania, Sweden (1999)
    Springer
    Hydrobiologia 404 (1999), S. 27-40 
    Details
    ISSN: 1573-5117
    Keywords: phytoplankton ; fish reduction ; phosphorus ; biomanipulation ; blue-green algae ; cyanobacteria ; Microcystis ; Anabaena ; Aphanizomenon ; Aulacoseira ; cryptomonads
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The algal record from Lake Ringsjön covers a period of more than 100 years. Towards the end of the 19th century, the lake had a well-functioning commercial fishery, when a brownish mess began to appear in the water, clogging-up the fishing nets and making fishing difficult. This was the first record of algal problems in the lake. Following complaints from the fishermen, the algal flora was investigated and the mess was stated to be a mass development of diatoms belonging to the genus Melosira ( Aulacoseira). Diatom maxima then appeared regularly in spring and autumn, whereas blue-green algae only occurred occasionally and in low abundances. Between 1900 and 1950, nutrient concentrations slowly increased in the lake. Algal blooms of Anabaena lemmermannii and Gloeotrichia echinulata began to appear in summer. Between 1960 and 1980, the lake developed into a hypertrophic status with extensive blooms of blue-green algae from May to October, including high biomasses of mainly Microcystis spp. This severe pollution started with increased usage of the lake, increased tourism and recreation, intensified farming with the introduction of artificial fertilization, and also the diversion of sewage water from a sewage treatment plant. In 1968, cattle death was reported and in 1981, algal toxicity was verified by mouse bioassay. After a period of extremely poor water quality, the lake began to show signs of improvement as a result of the nutrient and fish reduction programmes. The very heavy blooms of blue-green algae decreased and the duration of blooms became shorter. The Microcystis species were to a certain extent replaced by Anabaena and Aphanizomenon species, and biodiversity of algae increased. With respect to the algal community, the lake has improved considerably, but is still eutrophic and suffers summer blooms of toxic blue-green algae.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003757504155
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 92
    Electronic Resource
    Electronic Resource
    Synthesis of theoretical and empirical experiences from nutrient and cyprinid reductions in Lake Ringsjön (1999)
    Springer
    Hydrobiologia 404 (1999), S. 145-156 
    Details
    ISSN: 1573-5117
    Keywords: biomanipulation ; nutrient reduction ; zooplankton ; phytoplankton ; bottom-up ; top-down ; phosphorus ; submerged vegetation ; benthic macrofauna
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The reduction in external phosphorus load to Lake Ringsjön during the 1980s, did not result in improved water transparency during the following ten-year period. Furthermore, a fish-kill in the Eastern Basin of the lake, in addition to a cyprinid reduction programme (biomanipulation; 1988–1992), in contrast to theory, did not lead to any increase in zooplankton biomass or size. This absence of response in the pelagic food chain may have been attributed to the increase in abundance of YOY (0+) fish, following the fish reduction programme. Despite the lack of effect on zooplankton, there was a decrease in phytoplankton biomass, a change in species composition and an increase in water transparency following biomanipulation. In 1989, one year after the fish-kill in Eastern Basin, the Secchi depth (summer mean) increased from 60 cm to 110 cm. In the following years, water transparency increased further, despite an increase in phosphorus loading. An unexpected effect of the biomanipulation was an increase in benthic invertebrate and staging waterfowl abundances, which occurred 2–4 years after fish reduction. Hence, the response in the benthic community following biomanipulation was considerably stronger than in the pelagic community. A likely explanation is that reduction in abundance of the benthic feeding fish species bream (Abramis brama), strongly affected the benthic invertebrate fauna. In this paper, we present what we believe happened in Lake Ringsjön, and which processes are likely to have been important at various stages of the restoration process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003788900521
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 93
    Electronic Resource
    Electronic Resource
    Lumbriculids, branchiobdellidans and leeches: an overview of recent progress in phylogenetic research on clitellates (1999)
    Springer
    Hydrobiologia 406 (1999), S. 281-290 
    Details
    ISSN: 1573-5117
    Keywords: evolution ; Branchiobdellida ; Hirudinea ; Clitellata ; Lumbriculidae
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The debates about the relationship among clitellate taxa at research conferences on aquatic oligochaetes have provided two alternative hypotheses. While both involve cladistic analyses, the differences focus on questions of homology. A single unique synapomorphy supports a taxon consisting of Branchiobdellida plus Lumbriculidae. Muscle ultrastructure provides a potential autapomophy for Lumbriculidae within the clade, while Branchiobdellida has many autapomophies. Some proposed synapomorphies for a Branchiobdellida plus Hirudinea grouping (jaws, oral sucker) are not based on homologous structures. Others (loss of chaetae, median male pore) are not unique, or are based on potentially convergent characters. Initial molecular analyses support a Branchiobdellida - Hirudinea grouping. A preliminary manually drawn cladogram based on re-evaluated characters supports Lumbriculidae, Branchiobdellida, Acanthobdella and Euhirudinea as a monophyletic taxon. Observations on sperm ultrastructure support this hypothesis. If substantiated, a very considerable change in nomenclature will result. However, before any nomenclatural changes are proposed, a resolution of the apparently paraphyletic Oligochaeta is necessary.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003717107907
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 94
    Electronic Resource
    Electronic Resource
    Relationships between eutrophication variables: from nutrient loading to transparency (1999)
    Springer
    Hydrobiologia 408-409 (1999), S. 375-387 
    Details
    ISSN: 1573-5117
    Keywords: eutrophication ; multi-lake studies ; phosphorus ; nitrogen ; chlorophyll-a ; transparency ; zooplankton ; macrophytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Monitoring data obtained from 231 freshwater lakes and ponds in the Netherlands, covering the period 1980–1996, were used to analyse the relationships between (a) transparency and chlorophyll-a, and the effect of system characteristics on this relationship, (b) chlorophyll-aand nutrient concentrations, and the effect of biological variables and (c) nutrient concentrations and nutrient loading. (a) Chlorophyll-aimposes a maximum on water transparency, but deviations from this maximum can be large. Reducing chlorophyll-a, therefore, does not guarantee a sufficient improvement of transparency. Soil type and the average depth of a lake were shown to influence the relationship between chlorophyll-aand transparency. (b) The maximum ratios of both chlorophyll-a: total-P and chlorophyll-a: total-N were higher in systems dominated by filamentous cyanobacteria than in systems dominated by other algae, indicating the efficiency of the former group with respect to nutrients. In systems with an areal coverage with submersed macrophytes above 5%, concentrations of chlorophyll-aand nutrients were lower than in systems with lower coverages. The ratios between chlorophyll-aand nutrients were lower at coverages larger than 10%. This indicates both bottom-up and top-down control of algae by macrophytes. Grazing pressure by zooplankton was also found to lower the chlorophyll-a: nutrient ratios. (c) System specific linear relationships were found between the average concentrations of total-P and total-N in the incoming water and the summer mean concentration in the lake. This allows the assessment of admissible loads for individual lakes, with narrower confidence limits compared to traditional relationships based on combined data from many lakes. From the analysis, it is concluded that the chain of relationships from nutrient loading to transparency is complex, and depends on biological variables as well as system characteristics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1017090931476
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 95
    Electronic Resource
    Electronic Resource
    Relationships of some ecological factors with the associations of vegetation in British rivers (1999)
    Springer
    Hydrobiologia 415 (1999), S. 117-122 
    Details
    ISSN: 1573-5117
    Keywords: vegetation ; floristic associations ; habitat ; enrichment ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract During River Habitat Surveys on the physical structure of watercourses in Britain between 1995 and 98, detailed assessments of the floristic associations, physical habitat and water chemistry were made at 165 sites over a wide range of vegetation types. Botanical data from a total of 340 relevés from within these RHS were recorded. The vegetation was classified phyto-sociologically on the basis of the abundance of characteristic species, resulting in 45 aquatic, swamp and mire associations being identified together with nine other communities which could not be completely classified phyto-sociologically. The associations were assigned to 22 alliances, 13 orders and 11 classes excluding communities dominated by filamentous algae. Water enrichment (as soluble and total phosphorus) was the most significant factor for the differentiation of the communities but pH, conductivity and alkalinity were also important.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003820308436
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 96
    Electronic Resource
    Electronic Resource
    Biomass characterization of Azolla filiculoides grown in natural ecosystems and wastewater (1999)
    Springer
    Hydrobiologia 415 (1999), S. 323-327 
    Details
    ISSN: 1573-5117
    Keywords: biofilter ; productivity ; phosphorus ; water quality ; Azolla
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The aquatic pteridophyte Azolla, a small-leaf floating plant, which lives in symbiosis with a nitrogen fixing cyanobacteria, Anabaena azollae, was widespread throughout water channels and hydrographic basins of Portugal. Azolla is also the aim of a study for its utilization as a biofilter for wastewater purification, namely for phosphorus removal (± 36%). The goal of this work is to compare the growth characteristics and biomass composition of this water fern in natural ecosystems with those obtained in some wastewaters. Plant growth rate (0.107± 0.037 d-1) and productivity (5.8 g dw m-2 d-1) suggest that Azolla can grow well in partially treated domestic wastewater, but not in diluted pig wastes. This fact, associated to its biomass composition, namely in phosphorus content (1.38 ±0.20%), increase the possibility of this plant being used to improve wastewater discharge quality. It may also be possible to use the biomass as a biofertiliser or as a feed supplement for aquatic and terrestrial animals due to its protein, crude fiber and mineral content.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1003824426183
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 97
    Electronic Resource
    Electronic Resource
    Alternative Ways to Become a Juvenile or a Definitive Phenotype (and on Some Persisting Linguistic Offenses) (1999)
    Springer
    Environmental biology of fishes 56 (1999), S. 17-38 
    Details
    ISSN: 1573-5133
    Keywords: embryo ; larva ; metamorphosis ; indirect or direct development ; life-history model ; altricial ; precocial ; allometry ; fish biologists vs. fishery biologists ; alprehost ; ontogeny ; evolution
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Lack of knowledge of early and juvenile development often makes it difficult to decide when a fish becomes a juvenile or, for that matter, a definitive phenotype. According to the established life-history model, a fish develops naturally in a saltatory manner, its entire life consisting of a sequence of stabilized self-organizing steps, separated by distinct less stabilized thresholds. Changes are usually introduced during thresholds. In principle, there are two ways to reach the juvenile period: by indirect or by direct development. Indirectly developing fishes have a distinct larva period that ends in a cataclysmic or mild remodeling process, called metamorphosis, from which the fishes emerge as juveniles. During metamorphosis, most temporary organs and structures of the embryos and larvae are replaced by definitive organs and structures that are also possessed by the adults. In contrast, directly developing fishes have no larvae. Their embryos develop directly into juveniles and do not need major remodeling. Consequently, the beginning of their juvenile period is morphologically and functionally less distinct than in indirect development. The life-history model helps to find criteria that identify the natural boundaries between the different periods in the life of a fish, among them, the beginning of the juvenile period. Looking at it from a different angle, when ontogeny progresses from small eggs with little yolk, larvae are required as the necessary providers of additional nutrients (‘feeding entities’ similar to amphibian tadpoles or butterfly caterpillars) in order to accumulate materials for the metamorphosis into the definitive phenotypes. Directly developing fishes start with large demersal eggs provided with an adequate volume of high density yolk and so require no or little external nutrients to develop into the definitive phenotype. These large eggs are released and develop in concentrated clutches. It therefore becomes possible and highly effective to guard them in nests or bear them in external pouches, gill chambers or the buccal cavity. Viviparity is the next natural step. Now the maternal investment into large yolks can be supplemented or replaced by direct food supply to the developing embryos like, for example, the secretion of uterine histotrophe or nutrient transfer via placental analogues. When the young of guarders and bearers start exogenous feeding, they are much larger or better developed than larvae of nonguarders and the larva period in the former is reduced to a vestige or eliminated entirely. In the latter case, the juvenile period begins with the first exogenous feeding. Such precocial fishes are more specialized and able to survive better in competitive environments. In contrast, altricial forms retain or revert to a life-history style with indirect development and high fecundity when dispersal is advantageous or essential. Fishes become juveniles when the definitive phenotype is formed in most structures, either indirectly from a larva via metamorphosis or directly from the embryo.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007502209082
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 98
    Electronic Resource
    Electronic Resource
    A simulation model of organic matter and nutrient accumulation in mangrove wetland soils (1999)
    Springer
    Biogeochemistry 44 (1999), S. 93-118 
    Details
    ISSN: 1573-515X
    Keywords: Everglades National Park ; mangrove soils ; organic matter ; nitrogen ; phosphorus ; sedimentation ; simulation model
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract The distribution and accumulation of organic matter, nitrogen (N) and phosphorus (P) in mangrove soils at four sites along the Shark River estuary of south Florida were investigated with empirical measures and a process-based model. The mangrove nutrient model (NUMAN) was developed from the SEMIDEC marsh organic matter model and parameterized with data from mangrove wetlands. The soil characteristics in the four mangrove sites varied greatly in both concentrations and profiles of soil carbon, N and P. Organic matter decreased from 82% in the upstream locations to 30% in the marine sites. Comparisons of simulated and observed results demonstrated that landscape gradients of soil characteristics along the estuary can be adequately modeled by accounting for plant production, litter decomposition and export, and allochthonous input of mineral sediments. Model sensitivity analyses suggest that root production has a more significant effect on soil composition than litter fall. Model simulations showed that the greatest change in organic matter, N, and P occurred from the soil surface to 5 cm depth. The rapid decomposition of labile organic matter was responsible for this decrease in organic matter. Simulated N mineralization rates decreased quickly with depth, which corresponded with the decrease of labile organic matter. The increase in organic matter content and decrease in soil bulk density from mangrove sites at downstream locations compared to those at upstream locations was controlled mainly by variation in allochthonous inputs of mineral matter at the mouth of the estuary, along with gradients in mangrove root production. Research on allochthonouns sediment input and in situ root production of mangroves is limited compared to their significance to understanding nutrient biogeochemistry of these wetlands. More accurate simulations of temporal patterns of nutrient characteristics with depth will depend on including the effects of disturbance such as hurricanes on sediment redistribution and biomass production.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00993000
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 99
    Electronic Resource
    Electronic Resource
    Nutrient budgets and biogeochemistry in an experimental agricultural watershed in Southeastern China (1999)
    Springer
    Biogeochemistry 45 (1999), S. 1-19 
    Details
    ISSN: 1573-515X
    Keywords: Chaohu Lake ; chemical fertilizer ; cycling ; denitrification ; multipond system ; nitrogen ; nutrient budget ; phosphorus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract During a two-year field study, an annual nutrient budget and cycles were developed for a small agricultural watershed. The study emphasized the integrated unit of the watershed in understanding the biogeochemistry. It was found that the total nutrient input was 39.1× 104 kg nitrogen and 3.91×104 kg phosphorus in the year 1995, of which the greatest input of nutrients to the watershed was chemical fertilizer application, reaching 34.7×104 kg (676 kg/ha) nitrogen and 3.88×104 kg (76 kg/ha) phosphorus. The total nutrient output from the watershed was 13.55×104 kg nitrogen and 0.40×104 kg phosphorus, while the largest output of nitrogen was denitrification, accounting for 44.1% of N output; the largest output of phosphorus was sale of crops, accounting for 99.4% of P output. The results show that the nutrient input is larger than output, demonstrating that there is nutrient surplus within the watershed, a surplus which may become a potential source of nonpoint pollution to area waters. The research showed that both denitrification and volatilization of nitrogen are key ways of nitrogen loss from the watershed. This suggests that careful management of fertilizer application will be important for the sustainable development of agriculture. The research demonstrated that a multipond system within the watershed had high retention rate for both water and nutrients, benefiting the water, nutrient and sediment recycling in the terrestrial ecosystem and helping to reduce agricultural nonpoint pollution at its source. Therefore, this unique watershed system should be recommended due to its great potential relevance for sustainable agricultural development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00992870
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 100
    Electronic Resource
    Electronic Resource
    Nutrient losses in runoff from grassland and shrubland habitats in Southern New Mexico: I. rainfall simulation experiments (1999)
    Springer
    Biogeochemistry 45 (1999), S. 21-34 
    Details
    ISSN: 1573-515X
    Keywords: Chihuahuan desert ; desert ; desertification ; grassland ; nitrogen ; nutrient budgets ; phosphorus ; runoff
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Rainfall simulation experiments were performed in areas of semiarid grassland (Bouteloua eriopoda) and arid shrubland (Larrea tridentata) in the Chihuahuan desert of New Mexico. The objective was to compare the runoff of nitrogen (N) and phosphorus (P) from these habitats to assess whether losses of soil nutrients are associated with the invasion of grasslands by shrubs. Runoff losses from grass- and shrub-dominated plots were similar, and much less than from bare plots located in the shrubland. Weighted average concentrations of total dissolved N compounds in runoff were greatest in the grassland (1.72 mg/1) and lowest in bare plots in the shrubland (0.55 mg/1). More than half of the N transported in runoff was carried in dissolved organic compounds. In grassland and shrub plots, the total N loss was highly correlated to the total volume of discharge. We estimate that the total annual loss of N in runoff is 0.25 kg/ha/yr in grasslands and 0.43 kg/ha/yr in shrublands — consistent with the depletion of soil N during desertification of these habitats. Losses of P from both habitats were very small.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00992871
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...