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
    Group-I intron family in the nuclear ribosomal RNA small subunit genes of Cenococcum geophilum isolates (1996)
    Springer
    Current genetics 29 (1996), S. 377-387 
    Details
    ISSN: 1432-0983
    Keywords: Key words Self-splicing ; Group-I intron ; Ribosomal RNA ; Cenococcum geophilum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract  A family of optional group-I introns was found near the 3′ end of the nuclear small subunit rRNA genes in 61 out of 70 isolates of the deuteromycete mycorrhizal fungus Cenococcum geophilum. DNA sequence polymorphisms among the introns (termed CgSSU introns) from ten of the isolates were studied. The sequences, ranging in size from 488 to 514 nucleotides, were from 93.2% to 99.6% similar to each other. Mutations were less common in predicted base-paired regions (33% of all mutations) than in free-standing regions (67%). The introns were self-spliced in vitro and were closest to subgroup IC1 according to sequence and predicted secondary structure. Group-I intron pairing regions P1 through P10, including core regions P, Q, R and S, were present in all ten CgSSU introns studied. No lengthy open reading frames were found in any of the introns, indicating that the introns do not encode a protein, and therefore may not be mobile. It is likely that a single intron entered a progenote of C. geophilum and changed as the species evolved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002940050059
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Comparison of ribosomal DNA ITS regions among geographic isolates of Cenococcum geophilum (1999)
    Springer
    Current genetics 35 (1999), S. 527-535 
    Details
    ISSN: 1432-0983
    Keywords: Key wordsCenococcum geophilum ; Internal transcribed spacer (ITS) ; Ribosomal DNA (rDNA) ; Group-I intron ; Mycorrhizae ; RNA secondary structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cenococcum geophilum is an ecologically important mycorrhizal fungus with a global distribution and a wide host range. It has been difficult to study since it forms only sterile mycelia and, occasionally, sclerotial bodies. Because of its lack of morphological variability, its taxonomy and phylogenetic origins have until recently remained unclear. To better understand the genetic variation and environmental adaptability of C. geophilum, a molecular phylogeny was constructed based on the nuclear ribosomal DNA internal transcribed spacers (ITS1 and ITS2) of 69 isolates from various hosts and habitats. The results suggest DNA sequence conservation in the ITS regions. Considering its broad geographic and host range, this ITS conservation was unexpected. Our data imply that the ITS2 region is under evolutionary pressure to maintain the RNA secondary structure (similar to the pressure on the CgSSU introns) involved in the post-transcriptional processing of rRNA. Also, C. geophilum has very short ITS regions, thus limiting the number of mutable sites. This limited ITS variability suggests a recent radiation of C. geophilum, having been geographically distributed by a variety of efficient processes. C. geophilum appears to be a single taxonomic entity, possibly a single species. Therefore, it is an extremely adaptable, as well as ecologically valuable, taxon.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002940050449
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Backpropagation of an Image Similarity Metric for Autoassociative Neural Networks (2000)
    Springer
    Pattern analysis and applications 3 (2000), S. 31-38 
    Details
    ISSN: 1433-755X
    Keywords: Keywords: Autoassociative neural networks; Error function; Image compression;; Visual difference predictor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract. Autoassociative Neural Networks (AANNs) are most commonly used for image data compression. The goal of an AANN for image data is to have the network output be ‘similar’ to the input. Most of the research in this area use backpropagation training with Mean-Squared Error (MSE) as the optimisation criteria. This paper presents an alternative error function called the Visual Difference Predictor (VDP) based on concepts from the human-visual system. Using the VDP as the error function provides a criteria to train an AANN more efficiently, and results in faster convergence of the weights, while producing an output image perceived to be very similar by a human observer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s100440050004
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Changes in aggregate stability, nutrient status, indigenous microbial populations, and seedling emergence, following inoculation of soil withNostoc muscorum (1994)
    Springer
    Biology and fertility of soils 18 (1994), S. 209-215 
    Details
    ISSN: 1432-0789
    Keywords: Aggregate stability ; Soil polysaccharide Soil fertility ; Soil inoculation ; Seedling emergenceNostoc muscorum ; Cyanobacteria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract The potential of the N2-fixing cyanophyteNostoc muscorum for improving the aggregate stability of a poorly structured silt loam soil was studied in a greenhouse experiment. Inoculum rates were 1.61×105 cells g-1 soil dry weight (low rate) and 4.04×105 cell g-1 soil dry weight (high rate), approximately equivalent to a field application of 2 and 5 kg ha-1 cells dry weight, respectively.N. muscorum numbers had increased 8-fold (low rate) and 10-fold (high rate) by 300 days after inoculation, indicating not only survival but proliferation. Increases in soil polysaccharides, determined as soil carbohydrate C, were 2.96–3.49 time the values in the non-inoculated soils and aggregate stability had incrased by an average of 18% on day 300. Inoculation withN. muscorum also had a pronounced effect on soil chemical and biological properties, with total C increasing by 50–63% and total N increasing by 111–120%. Increases in the soil indigenous microbial population were recorded, with numbers of bacteria 500, fungi 16, and actinomycetes 48 times the non-inoculated values on day 300 in the high-rate soil. The emergence of lettuce seedlings (Lactuca sativa var. Saladin) in undisturbed inoculated 300-day soils was 56% (low rate) and 52% (high rate) higher than in non-inoculated soils. However, homogenising soils and irrigating (to smulate ploughing and surface crusting) significantly reduced this increase in both treatments, although emergence in inoculated soils was still greater by 45% (low) and 24% (high). It is recommended that inoculated soils be left undisturbed prior to planting. The effects ofN. muscorum on soil physical, chemical, and biological properties indicate the possible benefits of cyanobacteria as soil inoculants, not only for the improvement of soil aggregate stability but also as a means of improving seedling emergence.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00647668
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Isolation of mutants sensitive to 2-amiriopurine and alkylating agents and evidence for the role of DNA methylation in Penicillium chrysogenum (1986)
    Springer
    Current genetics 10 (1986), S. 557-560 
    Details
    ISSN: 1432-0983
    Keywords: Methylation ; DNA ; Penicillium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Using high performance liquid chromatography, the presence of N6-methyladenine has been found at a level of 0.1 mol percent in DNA extracted from Penicillium chysogenum. No 5-methylcytosine was detected. A mutant strain HP547, which is sensitive to the lethal effects of N-methyl-N1-nitro-N-nitrosoguanidine, methylmethane sulphonate and the base analogue 2-aminopurine shows an increased spontaneous mutation rate and no detectable DNA methylation. Comparison of restriction enzyme digests of wild type and undermethylated strains indicated that methylation was occurring at a different sequence to that of the Dam methylase system of E. coli.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00447390
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Potential exposure of commercial seed-treating applicators to the pesticides carboxin-thiram and lindane (1983)
    Springer
    Bulletin of environmental contamination and toxicology 31 (1983), S. 244-250 
    Details
    ISSN: 1432-0800
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01607901
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    DNA Changes in Tissues Entrapped in Plant Resins (the Precursors of Amber) (2000)
    Springer
    Naturwissenschaften 87 (2000), S. 70-75 
    Details
    ISSN: 1432-1904
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Natural Sciences in General
    Notes: Abstract  There have been many reports characterizing DNA from amber, which is a fossil version of plant resin. Here we report an investigation of the effects of plant resin (from Pseudotsuga menziesii) and drying conditions on the preservation of DNA in biological tissues. We examined the degree of degradation of the DNA by agarose gel electrophoresis of extracted DNA, by polymerase chain reaction, and by DNA sequencing. The plant resin alone appeared to cause little or no damage to DNA. Tissue immersed in plant resin that dried rapidly (exposed to sunlight) contained DNA with little apparent damage. Tissue immersed in the resin that was dried slowly (in shade without sunlight) contained DNA with some degradation (3.5% nucleotide changes). The tissue that was immersed in the resin that was constantly hydrated (by immersion in water) yielded DNA that was severely damaged (50–62% nucleotide changes). Transversions outnumbered transitions in these samples by a ratio of 1.4 : 1. A piece of Baltic amber immersed in water for 5 days appeared to be impervious to the water. Thus amber inclusions that initially dried rapidly have the potential to yield undamaged DNA. Those that dried slowly may contain damaged DNA and may be unsuitable for phylogenetic and other studies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s001140050012
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Shoot regeneration and plant acclimatization of the wetland monocot Cattail (Typha latifolia) (1998)
    Springer
    Plant cell reports 18 (1998), S. 71-75 
    Details
    ISSN: 1432-203X
    Keywords: Key wordsTypha latifolia ; Cattail ; Remediation ; Shoot regeneration ; Wetland monocot
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract A regeneration system for broadleaf cattail (Typha latifolia), a common freshwater wetland monocot, was established. Callus was induced from 3 day-old seedlings on Murashige and Skoog medium supplemented with picloram or 2,4-dichlorophenoxyacetic acid (2,4-D). Picloram induced more callus growth than 2,4-D. Callus proliferated predominantly from the root-shoot junction and sporadically from the roots. Upon transfer to N6-benzyladenine-supplemented medium, callus regenerated shoots. The mode of regeneration was organogenesis, with shoots arising from organized areas of callus. The regenerated shoots rooted in vitro and, on transfer to pots containing a commercial potting mix, were established in a greenhouse. The plants grew vigorously and produced a high root mass. No albinos and no morphological aberrations were observed in the regenerates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002990050534
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Transient expression of electroporated DNA in monocotyledonous and dicotyledonous species (1987)
    Springer
    Plant cell reports 6 (1987), S. 265-270 
    Details
    ISSN: 1432-203X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Transient expression of electroporated DNA was monitored in protoplasts of several monocot and dicot species by assaying for expression of chimeric chloramphenicol acetyltransferase (CAT) gene constructions. Expression was obtained in the dicot species of Daucus carota, Glycine max and Petunia hybrida and the monocot species of Triticum monococcum, Pennisetum purpureum, Panicum maximum, Saccharum officinarum, and a double cross, trispecific hybrid between Pennisetum purpureum, P. americanum, and P. squamulatum. Recovery and viability of protoplasts after electroporation decreased with increasing voltages and capacitance while CAT activity increased up to a critical combination of voltage and capacitance beyond which the activity dramatically decreased. The optimal compromise between DNA uptake and expression versus cell survival was determined for D. carota and applied successfully to the other species. Maximum transient expression occurred 36 hours after electroporation of D. carota. The potential for using this procedure to rapidly assay gene function in dicot and monocot cells and application of this technique to obtain transformed cereals is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00271995
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Some evidence for the existence of turgor pressure gradients in the sieve tubes of willow (1975)
    Springer
    Planta 126 (1975), S. 259-267 
    Details
    ISSN: 1432-2048
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Sieve tube sap was collected either from the severed stylets of Tuberolachnus salignus (Gmelin) or via incisions made into the phloem of small willow trees or potted cuttings. Measurements of the osmotic potential (O.P.) of sap samples showed a gradient to exist in the presumed direction of assimilate transport, ie from apex to base of the stem. In most experiments samples of phloem tissue were taken after the collection of sieve tube sap, the water potential of these pieces of tissue being measured in a psychometer. Although a water potential gradient existed in the opposite sense to the O.P. gradient in the sap (lowest water potential at the apex of the stem), the difference between O.P. and W.P. indicated the turgor of the sieve tubes to be higher at the apex than at the base of the stem. The magnitude of the turgor gradient measured in this way lay between 0.5 and 2.7 atm m-1. In other experiments severed stylets only were used to determine whether a hydrostatic gradient can exist in willow sieve tubes. After measurement of flow rates from stylets sited at the apex and base of willow stems, the Poiseuille expression was used to calculate the pressure at the point of stylet puncture. These experiments gave values for the pressure gradient (in the presumed direction of assimilate flow) of between 1.9 and 4.7 atm m-1.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00388967
    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...