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91.
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Mutants of Group D1Salmonella Carrying the Somatic Antigen of Group A Organisms: Isolation and Serological Characterization 总被引:2,自引:2,他引:0
O antigen mutants were obtained from Salmonella durban, a group D(1) organism, by treatment with N-methyl-N'-nitro-N-nitrosoguanidine. Serological studies demonstrated that the mutants lost the O-9 antigen factor of the parent organism but acquired the O-2 factor specific to group A Salmonella. Lipopolysaccharides of the mutant strains contained paratose which determines the specificity of O-2 factor. Tyvelose, present in the wild-type lipopolysaccharide, was not found in the mutants. H antigens and other biological characteristics of the mutant strains were the same as those of the wild-type organism. The present finding implies that group A Salmonella species might be derived from group D(1) organisms. 相似文献
93.
Mutants of Group D1Salmonella Carrying the Somatic Antigen of Group A Organisms: Evidence for the Lack of Cytidine Diphosphate Paratose-2-Epimerase Activity 总被引:3,自引:3,他引:0 下载免费PDF全文
The mutant strains of Salmonella durban that possessed O antigen 2, 12 of group A Salmonella were defective in the cytidine diphosphate paratose-2-epimerase activity. The enzyme preparation of the mutant strains catalyzed the conversion of cytidine diphosphate glucose into cytidine diphosphate paratose but not into cytidine diphosphate tyvelose. The defect in the epimerase activity was also confirmed by the use of purified cytidine diphosphate paratose as a substrate. The specificity of dideoxyhexosyl transferase catalyzing the formation of the group-specific determinant is discussed. 相似文献
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Nitrate and ammonium were shown to alter the growth ofRhodotorula glutinis var.salinaria in saline and non-saline media. In saline medium in which ammonium was the sole nitrogen source, ammonium inhibited growth
in the presence of molybdate ions. Detailed comparisons of the growth in saline and non-saline media when nitrate was supplemented
in the presence of molybdate ions showed that differences in utilizability of purine bases of nucleic acid were responsible
for the differences in growth,i.e. adenine increased the growth in such saline medium, but decreased it in non-saline medium. There was not such a specific
requirement for adenine in saline medium in the presence of molybdate ions when nitrate was substituted for ammonium as the
sole nitrogen source. It was suggested that adenine might provide the necessary skeleton of nucleic acid for serving nitrate
reduction in saline medium. 相似文献
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Staining patterns suggest that in the adeno-associated satellite virion there exist quasi single-stranded regions which are renatured after extraction to exhibit double strandedness. 相似文献