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121.
Don J. Brenner Jan Ursing Hervé Bercovier Arnold G. Steigerwalt G. Richard Fanning Jean Michel Alonso H. H. Mollaret 《Current microbiology》1980,4(4):195-200
Yersinia enterocolitica andY. enterocolitica-like strains were characterized by DNA relatedness. These strains formed four distinct DNA relatedness groups: (i) the 5
classical biotypes ofY. enterocolitica sensu stricto as designated by Wauters; (ii) strains that are rhamnose positive and also positive in tests for melibiose, α-methyl-d-glucoside, raffinose, and Simmons' citrate; (iii) strains that are rhamnose positive but negative in tests for melibiose,
α-methyl-d-glucoside, and raffinose; (iv) sucrose-negative, Voges-Proskauer-negative, trehalose-positive strains. 相似文献
122.
Michel Becker 《Plant Ecology》1980,40(3):155-161
Summary In a previous study, 772 floristics relevés, made in a large forest on calcareous soils (north-east France), had been treated by factorial analysis of correspondences in order to establish a site typology. The third axis separated chiefly Fagus and Quercus, which are very common in the forest, and various other ligneous or herbaceous species (see fig. 1). Two groups of relevés, homogeneous as for edaphic conditions, were choosen, having a significant position on this axis (with either positive or negative values). From this, floristic tables have been elaborated; they show clearly the influence of silvi culture (here high forest or coppice-with-standards) on part of both ligneous and herbaceous flora. Considering plant sociology, it appears that treating a stand as a coppice-with-standards can convert a Melico-Fagetum typicum (Eu-Fagion) into a Querceto Carpinetum typicum (Fraxino-Carpinion), and a Carici-Fagetum (Cephalanthero-Fagion) into a Querceto-Carpinetum primuletosum (Fraxino-Carpinion). Fortunately a large number of species are not influenced by the silviculture; this allows the identification of isopotential sites. Possible ecological causes are briefly discussed.
Nomenclature suivant: P. Fournier, 1961. Les quatre flores de France. Edition P. Le Chevalier, Paris. 1154 p. 相似文献
123.
124.
The proton ejection coupled to electron flow from succinate and/or endogenous substrate(s) to cytochrome c using the impermeable electron acceptor ferricyanide is studied in tightly coupled mitochondria isolated from two strains of the yeast Saccharomyces cerevisiae. (1) The observed H+ ejection/2e? ratio approaches an average value of 3 when K+ (in the presence of valinomycin) is used as charge-compensating cation. (2) In the presence of the proton-conducting agent carbonyl cyanide m-chlorophenylhydrazone, an H+ ejection/2e? ratio of 2 is observed. (3) The low stoichiometry of 3H+ ejected (instead of 4) per 2e? and the high rate of H+ back-decay (0.1615 and a half-time of 4.6 s for 10 mg protein) into the mitochondrial matrix are related to the presence of an electroneutral K+/H+ antiporter which is demonstrated by passive swelling experiments in isotonic potassium acetate medium. 相似文献
125.
Françoise Giraud Michel Claret K.Richard Bruckdorfer Bernadette Chailley 《生物化学与生物物理学报:生物膜》1981,647(2):249-258
Cholesterol depletion alters the apparent affinity of the internal cationic sites and the maximal translocation rate but not the affinity of the external cationic sites of the pump in human erythrocytes. To test whether these effects were mediated by a direct cholesterol-internal site interaction or by a change in membrane lipid order, the effects of five fluidizing amphiphiles (chlorpromazine, imipramine, benzyl alcohol, sodium oleate and sodium benzenesulphonate) on the kinetic parameters of the pump were determined. The cholesterol removal and all the agents used induced dose-response decreases in membrane lipid order as measured by fluorescence polarization or ESR. Positive and neutral amphiphiles mimicked the effects of cholesterol removal on the affinity of the internal sites of the pump and to a lesser extent on the maximal translocation rate. Anionic amphiphiles had no effect on internal sites, probably because they distributed preferentially within the outer leaflet on the membrane. These results indicate that cholesterol controls the affinity of the internal sites of the pump by altering the membrane lipid order. In contrast, neither cholesterol depletion nor the agents used altered the affinity of the external sites of the pump. This difference in sensitivity to membrane lipid order suggests that internal and external cationic sites, although borne by the same protein, are in different lipid environments. 相似文献
126.
Claude Auriault Joël Pestel Michel Joseph Jean-Paul Dessaint Andre Capron 《Cellular immunology》1981,62(1):15-27
Discharge of lysosomal enzymes, measured by release of β-glucuronidase and cytotoxicity against Schistosoma mansoni schistosomula, was studied when rat macrophages were incubated in the presence of either IgG peptides, resulting from the cleavage of nonimmune IgG by parasitic proteases, or nonimmune aggregated IgG. With peptides, the macrophage activity showed a dramatic decrease while they were stimulated by IgG aggregates. In contrast, the synthesis of lymphocyte activating factor by macrophages was unaffected. The hydrolysis of IgG is carried out by two distinct enzymatic molecules released into the medium by the larvae. The mechanism by which nonimmune IgG peptides or aggregates inhibit or stimulate macrophage activity, regulated by both parameters indicated above, is discussed and is suggested as a general regulation mechanism for the macrophage activity required for parasite survival in the host. 相似文献
127.
The first mammalian remain ever found in NewCaledonia is an upper tooth found by golddiggers in the Plio-Pleistocene terrace from the Diahot river. This tooth, given to the Muséum national d'Histoire naturelle (Paris) in 1876, was determined as a rhinoceros tooth and then completely forgotten. Its detailed study shows that it belongs to Zygomaturus, a large marsupial diprotodontid genus whose story is rather complicated. The Diahot tooth represents a new species of Zygomaturus, Z. diahotensis nov. sp., close to Z. trilobus from the Australian Pleistocene. That kinship suggests a Plio-Pleistocene land connection between Australia and New Caledonia, whereas till now New Caledonia was supposed to be separated from Australia since the end of the Cretaceous, because of the total absence of indigenous mammals, fossil or recent, in New Caledonia. The latest geological studies in the East Pacific do not contradict our hypothesis. 相似文献
128.
An efficient scavenger for radiolytically generated hydroxyl (OH) radicals, p-nitrosodimethylaniline, was used to try to substantiate the presence of this oxygen radical species in several biochemical systems. Most of these systems which were investigated had previously been assumed to generate OH radicals, e.g. the autoxidation of 6-hydroxydopamine, the hydroxylating system NADH/phenazine methosulfate, and the oxidation of xanthine or acetaldehyde by xanthine oxidase. We did not observe inhibition of the bleaching of p-nitrosodimethylaniline in oxygenated solutions by other scavengers of OH radicals nor, in the case of xanthine/xanthine oxidase, by catalase and superoxide dismutase. We therefore conclude that, under biochemical conditions as opposed to radiolysis or photolysis, no freely diffusable OH radicals are formed. Rather, a strongly oxidizing OH-analogous complex is considered to represent the p-nitrosodimethylaniline-detectable species formed under these conditions. 相似文献
129.
Superoxide anions do not react with hydroperoxides. 总被引:1,自引:0,他引:1
130.
Farah MG 《Cardiovascular diseases》1979,6(4):447-452
First heart sound alternans in the absence of pulsus alternans, or variation in heart rate (i.e., variation in PR interval), occurring in a patient with massive neoplastic pericardial effusion is described. The mechanism appears to be similar to that in electrical alternans and is shown by echocardiography to be related to the cardiac position within the pericardium, with the first heart sound intensity varying according to the distance of the heart from the chest wall. First heart sound alternans, electrical alternans, and alternating cardiac motion within the pericardium disappeared following pericardiocentesis. 相似文献