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
  • 1
    Electronic Resource
    Electronic Resource
    Influence of growth regulators on somatic embryogenesis, plantlet regeneration, and post-transplant survival of Echinochloa frumentacea (1992)
    Springer
    Plant cell reports 11 (1992), S. 368-371 
    Details
    ISSN: 1432-203X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract After placement on Murashige and Skoog's basal medium supplemented with 3–5 mg/l 2,4-D, immature inflorescence expiants of Echinochloa frumentacea gave rise to three distinct types of callus: a) loosely arranged and soft; b) compact and translucent; c) compact, sticky and mucilaginous. Somatic embryo formation occurred in type ‘b’ callus in about 18–24 d. Callus types ‘a’ and ‘c’ did not produce somatic embryos. The highest percentage of cultures exhibiting somatic embryogenesis occurred on the medium containing 5 mg/l 2,4-D and 0.5 mg/l kinetin. Somatic embryos also formed directly on the inflorescence (without intervening callus formation) in about 15% of the expiants placed on this medium. The addition of paclobutrazol or uniconazole (0.25 or 1 mg/l) to the medium had no influence on the percentage of cultures exhibiting direct somatic embryogenesis, but paclobutrazol slightly increased the mean number of somatic embryos per culture. Many of the callus-derived somatic embryos germinated when subcultured on basal MS medium supplemented with kinetin. Addition of paclobutrazol or uniconazole to the culture medium at 0.25 or 1 mg/l decreased somatic embryo germination and shoot elongation but increased root length and leaf width. Both paclobutrazol and uniconazole increased survival of the plantlets following transplanting to soil. Increased post-transplant survival was accompanied by reduced water loss from plantlets produced on culture media containing triazoles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00233368
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Estimates of bacterial productivity in marine sediments and water from a temperate saltmarsh lagoon (1992)
    Springer
    Microbial ecology 23 (1992), S. 195-209 
    Details
    ISSN: 1432-184X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Tritiated thymidine incorporation (TTI) into DNA was used to estimate bacterial productivity in sediment and water samples from two sites in Langebaan Lagoon, South Africa. Routine analysis of isotope dilution showed seasonal variations of approximately threefold in the thymidine precursor pool sizes for bacterial assemblages from each site. Dual label incorporation of [3H]-thymidine and 14C-leucine into DNA and protein, respectively, showed that pelagic but not sediment assemblages were in a balanced state of growth during TTI. This is the first report of dual label measurements of bacterial production in sediments. Sediments supported bacterial productivities that exceeded those in the water column by factors from five- to 950-fold, whereas bacterial abundance supported by sediments exceeded that in the water column by more than 3 orders of magnitude. Estimates of bacterial productivities in sediments were coincident with levels of organic content in sediments, but not with bacterial abundance. Measurements of TTI activity for 5 different benthic microhabitats at one lagoon site showed highest activity associated with seagrass beds (2.11 ± 0.84 nmol thymidine hours−1 g-1 dry weight), whereas activities decreased with depth (0.46 ± 0.21 nmol thymidine hours−1 g−I dry weight) below sediment surface.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00164096
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Feeding ecology and interannual variations in diet of larval jack mackerel, Trachurus declivis (Pisces: Carangidae), from coastal waters of eastern Tasmania (1992)
    Springer
    Marine biology 113 (1992), S. 11-20 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Crustacean microzooplankton were the main prey of larval Trachurus declivis collected in the summers of 1988, 1989 and 1990 from coastal waters of eastern Tasmania. The diet was dominated by harpacticoids (Microsetella rosea), cyclopoids (mainly Oithona spp.), calanoids and the calyptopis stage of the euphausiid Nyctiphanes australis. Bivalve veligers were occasionally eaten. Diets of larvae were affected by interannual variations in plankton composition, particularly in 1989 when intrusions of low-nutrient subtropical water exclused large zooplankters (e.g. N. australis) from the study area. Larvae≤6 mm selected for copepod nauplii; all larvae selected for M. rosea, cyclopoids, and the calyptopis stage of N. australis. Even though calanoids were a major prey taxon, there were proportionally fewer eaten than were present in the environment. In all, 78% of larvae taken during the daytime had food in their stomachs, as opposed to 38% of the larvae from night samples. Feedmid-morning and late afternoon. A gut evacuation rate of ∼4 to 6 h was estimated. We calculated that the larvae ate between 9 and 13% of their body weight in food per day. The larvae of T. declivis in this study were not sufficiently abundant to have an impact on their prey.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00367633
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Extracellular recordings from the motor nervous system of the nematode, Ascaris suum (1992)
    Springer
    Journal of comparative physiology 171 (1992), S. 17-28 
    Details
    ISSN: 1432-1351
    Keywords: Ascaris suum ; Nematode ; Motor nervous ; system ; Extracellular recording ; Extracellular spike
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary 1. The close association of muscle and neurons in Ascaris suum makes it difficult to determine whether spikes recorded from nerve cords originate in muscle or neurons. We have developed criteria that distinguish muscle and neuronal activity. There are two categories of extracellular spikes. 2. The first category consists of spikes with a wide range of amplitudes, marked by large spikes. These spikes, which can be recorded over lateral muscle and over the dorsal and ventral nerve cords, are abolished when muscle is disrupted or removed, or when curare is applied. Large spikes are relatively infrequent, are correlated with intracellularly recorded muscle events, and respond to polarizations of motor neurons, implying that they originate in muscle. 3. The second spike category, small amplitude spikes, is exclusive to the ventral nerve cord, occurs more frequently than large spikes and displays patterned firing. Small spikes are not affected by muscle removal or by curare, and are correlated with motor neuronal postsynaptic potentials, but not with intracellularly recorded muscle events. We infer that they originate in neurons. 4. Low level activity recorded extracellularly over nerve cords may represent muscle activity due to tonic motor neuronal synaptic transmission. It responds to motor neuronal polarization and is suppressed by curare or muscle removal.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00195957
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Ability of vertebral dimensions from a single radiograph to identify fractures (1992)
    Springer
    Calcified tissue international 51 (1992), S. 95-99 
    Details
    ISSN: 1432-0827
    Keywords: Epidemiology ; Vertebral fractures ; Morphology ; Prospective studies ; Fracture prevalence, incidence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Physics
    Notes: Summary It has been proposed that vertebral dimensions be used to objectively identify vertebral fractures, permitting standardization of methodology for comparisons between studies. In this report, we evaluate the ability of various vertebral dimensions and ratios to identify “abnormal” vertebrae. As no “gold standard” exists for prevalent vertebral fractures, we examined the ability of cross-sectional dimensions (at a single point in time) to detect fractured vertebrae that had been identified from changes in dimensions compared with previous radiographs. Theoretically, a cutoff of 3 SD below the mean will rarely misclassify normal vertebrae as fractured (specificity=99.9%). However, we found that this cutoff correctly identified only about 70% of the incident fractures. A less stringent criterion (2 SD below the mean; theoretical specificity=97.7%) identified about 85–90% of true fractures. Dividing by stature or other vertebral heights sometimes yielded marginal improvements in the ability of the anterior or posterior height dimensions to diagnose fractures. The results suggest that the true fracture prevalence may sometimes be substantially higher than suggested by cross-sectional vertebral measurements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00298495
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Almost difference sets and reversible divisible difference sets (1992)
    Springer
    Archiv der Mathematik 59 (1992), S. 595-602 
    Details
    ISSN: 1420-8938
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01194853
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Covalent immobilization of laccase on activated carbon for phenolic effluent treatment (1992)
    Springer
    Applied microbiology and biotechnology 37 (1992), S. 474-479 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary Laccase was covalently immobilised to activated carbon using four derivatisation methods. The highest bound activity was obtained using diimide coupling of laccase to carboxyl groups on the carbon. The maximum bound activity was reached at 11.5 mg laccase/g carbon. The carbon-immobilised laccase (CIL) was stable at pH values from 4.0 to 9.0. CIL stored at 4°C lost 38± 5% activity in the first 4 days, then a further 22±5% in 126 days. CIL showed increased stability to low pH although the pH optimum was unchanged. The activation energy of CIL was lower than soluble laccase. Oxidation of 2,6-dimethoxyphenol (DMP) by CIL in a packed-bed system was only 30±10% of that in a fluidised bed system. Of the initial activity 10–30% was retained after oxidation of seven batches of DMP. CIL removed colour from two industrial effluents. Colour was removed from pulp mill bleach plant effluent at 115 colour units per enzyme unit per hour and the removal rate increased with increasing effluent concentration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00180972
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Comparison of the catalytic and inhibitory properties of Pachysolen tannophilus xylose reductase to rat lens aldose reductase (1992)
    Springer
    Applied microbiology and biotechnology 37 (1992), S. 109-113 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary The catalytic and inhibitory profiles of xylose reductase isolated from the yeast Pachysolen tannophilus (PTXR) are compared to those of aldose reductase (AR) obtained form rat lens. While both PTXR and rat lens AR are NADPH-specific enzymes and have an affinity for a variety of substrates such as d-xylose, d,l-glyceraldehyde, and 4-nitrobenzaldehyde, the enzymes differ in their substrate affinity profiles. Also, PTXR is not inhibited by standard inhibitors of AR thus supporting a hypothesis that this enzyme may not possess the inhibitor binding site found in rat lens AR.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00174213
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Sharp estimates for Dirichlet eigenfunctions in horn-shaped regions (1992)
    Springer
    Communications in mathematical physics 150 (1992), S. 209-215 
    Details
    ISSN: 1432-0916
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics , Physics
    Notes: Abstract We prove sharp exponential decay for the Dirichlet eigenfunctions in horn-shaped regions in the plane. The estimate is obtained using a method of Carleman which is widely used in the study of harmonic measure. Such estimates can be applied to study the intrinsic ultracontractivity properties of the heat semigroup for such regions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02096574
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Neodymium isotopic evidence for the tectonic assembly of Late Archean crust in the Slave Province, northwest Canada (1992)
    Springer
    Contributions to mineralogy and petrology 111 (1992), S. 493-504 
    Details
    ISSN: 1432-0967
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract The ca. 2.7–2.5 Ga Slave Province is a “granitegreenstone” terrane comprising deformed sedimentary and subordinate volcanic belts extensively intruded by granitoid rocks. The Nd isotopic data are reported for 58 samples of supracrustal and granitoid rocks exposed along a 400 km, east-west, transect at 65°N across the structural grain of the province. Initial ɛ Nd values reveal distinctly different crustal sources in the eastern compared to the western parts of the province, as expected from tectonic assembly of the province through accretion of juvenile crust to older continental crust. Supracrustal sequences (ca. 2.71–2.65 Ga) from the central and eastern parts of the province have positive ɛ Nd(1) values (+0.3 to +3.6), consistent with juvenile sources and formation remote from significantly older crust. Syn to late-deformation (ca. 2.63–2.60 Ga), mantle-derived diorites and related tonalites (type I) from the central and eastern parts of the province have similar initial ɛ Nd values (-0.1 to +2.7). In contrast, samples from the westernmost plutons, which intrude exposed pre-3.1 Ga crust, have much lower ɛ Nd(1) values (-1.0 to4.6) suggesting contamination of these magmas by older crust. The ɛ Nd(1) values of post-deformation granites (s.s.) (type II) also vary systematically across the province: values for granites west of longitude 110°30′W range from-0.2 to -5.3; those to the east range from +0.6 to +3.7. These data suggest mixed crustal sources dominated by Mid to Early Archean material (ɛ Nd-2.6 to- 17 at 2.6 Ga) for the western granitoid rocks and juvenile sources for the eastern granites. The Nd isotopic data are consistent with the geology of the province in that exposures of Mid to Early Archean crustal rocks, predating the principal 2.7–2.5 Ga orogenic event are restricted to the western part of the province. The asymmetric pattern defined by the Nd isotopic data indicates the presence of distinct crustal rocks beneath the Slave Province. Similar isotopic variations observed across Phanerozoic collisional orogens have been interpreted to reflect tectonic assembly of crust by accretion of juvenile crustal terranes to an older continental margin. This process may also have been an important mechanism in the cratonization of the Slave Province.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00320904
    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...