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171.
Résumé Dans des tissus de cobayes il existe une protéine capable de catalyser la réduction de l'acide déhydrascorbique en acide ascorbique. Sa distribution, sa purification, sa spécificité et son action en présence d'enzymes inhibitrices typiques ont été étudié. 相似文献
172.
R. N. Kirkwood P. E. Hughes R. G. Rodway 《Cellular and molecular life sciences : CMLS》1981,37(10):1114-1114
Summary The influence of bromocryptine treatment on the timing of vaginal patency and 1st oestrus in female rats was studied. No significant influence of bromocryptine on these parameters was noted, and it is concluded that suppression of prolactin secretion has no effect on puberty attainment.Acknowledgment. We thank Professor E. Flückiger and Dr H. Friedli, Pharmaceutical Division, Sandoz Ltd, Basle, Switzerland, for the donation of bromocryptine mesylate. 相似文献
173.
Summary Measurements were made of the deformability of the red cells of carp at different temperatures and compared with previous results obtained with another teleost fish (yellowtail) and human red cells. Changes with temperature are similar to those obtained with yellowtail, but interpretation of differences in terms of mean corpuscular volume alone are insufficient to account for the variations, which seem to be mainly due to differences in cellular deformability of the cells themselves.Acknowledgment. We wish to thank Karlheinz Götz for his excellent technical assistance. Reprint requests should be addressed to G.M.H. 相似文献
174.
Organization of polymers in the cell walls of some bacilli 总被引:19,自引:0,他引:19
175.
176.
Evolutionary diversification of the mammalian defensins 总被引:13,自引:0,他引:13
Hughes AL 《Cellular and molecular life sciences : CMLS》1999,56(1-2):94-103
Defensins are cysteine-rich cationic peptides that function in antimicrobial defense in both invertebrates and vertebrates. Three main groups of animal defensins are known: insect defensins; mammalian alpha-defensins and vertebrate beta-defensins. It has been difficult to determine whether these molecules are homologous or have independently evolved similar features, but overall the evidence favors a distant relationship. The best evidence of this relationship is structural, particularly from their overall three-dimensional structure and from the spacing of half-cystine residues involved in intra-chain disulfide bonds. Some evidence favors a closer relationship between vertebrate beta-defensins and insect defensins than between the two groups of vertebrate defensins. Examination of nucleotide substitutions between recently duplicated mammalian defensin genes shows that the rate of nonsynonymous (amino-acid-altering) substitution exceeds that of synonymous substitution in the region of the gene encoding the mature defensin. This highly unusual pattern of nucleotide substitution is evidence that natural selection has acted to diversify defensins at the amino acid level. The resulting rapid evolution explains why it is difficult to reconstruct the evolutionary history of these molecules. 相似文献