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141.
142.
An antiserum to ADP-ribosylated elongation factor 2 (ADPR-EF-2) from S. acidocaldarius was raised in rabbits using stained, homogenized, ADPR-EF-2-containing slices from SDS-gels as a source of antigen. Elongation factor 2 (EF-2) from S. acidocaldarius was cloned in E. coli and the expressed gene product was used in order to adsorb all anti-EF-2 antibodies which do not contain the ADP-ribosyl group within their epitopes, as E. coli is unable to synthesize the ADP-ribosyl acceptor diphthamide. The remaining antibodies were specific to ADP-ribosylated EF-2 from Thermoplasma acidophilum, S. acidocaldarius and Desulfurococcus mucosus. ADP-ribosylated EF-2 from eukaryotic sources also reacted with the adsorbed antiserum as shown for EF-2 isolated from the killi-fish Cynolebias whitei, the mouse species BALB/c and Han/Wistar rats. The adsorbed antiserum did not cross-react with ADP-ribosylated actin or rho protein or with FAD-containing D-amino acid oxidase. 相似文献
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Siegmund Fischer Maria Tortolero Jean-Pierre Piau Jean Delaunay Georges Schapira 《生物化学与生物物理学报:生物膜》1980,598(3):463-471
Human erythrocyte membranes contain a phosphoprotein phosphatase able to dephosphorylate membrane protein previously phosphorylated by the endogenous protein kinase.The level of dephosphorylation obtained after prolonged incubation is about one half of the phosphorylated residues.The characteristics of this enzyme are similar to those described for the cytoplasmic phosphoprotein phosphatase.In a membrane preparation the phosphorylation and dephosphorylation reactions can be repeated, at least twice, achieving similar levels of phosphate esterified or hydrolyzed.The coordination of these two enzyme systems might play a role in some of the functions attributed to the protein kinase system. 相似文献
145.
Raoul Huys Andreas Daffertshofer Peter Beek David Sanderson Gunter Siegmund 《Journal of applied physiology》2004,96(6):2341; author reply 2341-2341; author reply 2342
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148.
Background
Male-factor infertility is a common condition, and etiology is unknown for a high proportion of cases. Abnormal epigenetic programming of the germline is proposed as a possible mechanism compromising spermatogenesis of some men currently diagnosed with idiopathic infertility. During germ cell maturation and gametogenesis, cells of the germ line undergo extensive epigenetic reprogramming. This process involves widespread erasure of somatic-like patterns of DNA methylation followed by establishment of sex-specific patterns by de novo DNA methylation. Incomplete reprogramming of the male germ line could, in theory, result in both altered sperm DNA methylation and compromised spermatogenesis.Methodology/Principal Finding
We determined concentration, motility and morphology of sperm in semen samples collected by male members of couples attending an infertility clinic. Using MethyLight and Illumina assays we measured methylation of DNA isolated from purified sperm from the same samples. Methylation at numerous sequences was elevated in DNA from poor quality sperm.Conclusions
This is the first report of a broad epigenetic defect associated with abnormal semen parameters. Our results suggest that the underlying mechanism for these epigenetic changes may be improper erasure of DNA methylation during epigenetic reprogramming of the male germ line. 相似文献149.
Nana Nehrbass Eckart Winkler Jana Müllerová Jan Pergl Petr Pyšek Irena Perglová 《Biological invasions》2007,9(4):383-395
Mechanisms and consequences of biological invasions are a global issue. Yet, one of the key aspects, the initial phase of
invasion, is rarely observed in detail. Data from aerial photographs covering the spread of Heracleum mantegazzianum (Apiaceae, native to Caucasus) on a local scale of hectares in the Czech Republic from the beginning of invasion were used
as an input for an individual-based model (IBM), based on small-scale and short-time data. To capture the population development
inferred from the photographs, long-distance seed dispersal, changes in landscape structures and suitability of landscape
elements to invasion by H. mantegazzianum were implemented in the model. The model was used to address (1) the role of long-distance dispersal in regional invasion
dynamics, and (2) the effect of land-use changes on the progress of the invasion. Simulations showed that already small fractions
of seed subjected to long-distance dispersal, as determined by systematic comparison of field data and modelling results,
had an over-proportional effect on the spread of this species. The effect of land-use changes on the simulated course of invasion
depends on the actual level of habitat saturation; it is larger for populations covering a high proportion of available habitat
area than for those in the initial phase of invasion. Our results indicate how empirical field data and model outputs can
be linked more closely with each other to improve the understanding of invasion dynamics. The multi-level, but nevertheless
simple structure of our model suggests that it can be used for studying the spread of similar species invading in comparable
landscapes. 相似文献
150.
Aneta M. Białkowska Ewa Gromek Joanna Krysiak Barbara Sikora Halina Kalinowska Marzena Jędrzejczak-Krzepkowska Celina Kubik Siegmund Lang Fokko Schütt Marianna Turkiewicz 《Journal of industrial microbiology & biotechnology》2015,42(12):1609-1621
2,3-Butanediol (2,3-BD) synthesis by a nonpathogenic bacterium Bacillus licheniformis NCIMB 8059 from enzymatic hydrolysate of depectinized apple pomace and its blend with glucose was studied. In shake flasks, the maximum diol concentration in fed-batch fermentations was 113 g/L (in 163 h, from the hydrolysate, feedings with glucose) while in batch processes it was around 27 g/L (in 32 h, from the hydrolysate and glucose blend). Fed-batch fermentations in the 0.75 and 30 L fermenters yielded 87.71 g/L 2,3-BD in 160 h, and 72.39 g/L 2,3-BD in 94 h, respectively (from the hydrolysate and glucose blend, feedings with glucose). The hydrolysate of apple pomace, which was for the first time used for microbial 2,3-BD production is not only a source of sugars but also essential minerals. 相似文献