Journal ArticleDOI
Genetic Transfer of Shigella flexneri Antigens to Escherichia coli K-12.
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TLDR
The genes controlling synthesis of Shigella flexneri group- and type-specific antigens were transferred to Escherichia coli K-12 recipients by conjugation with an S.flexneri Hfr and results show that genes controlling the synthesis of S. flexNERi group antigen and type -specific antigen are widely separated on the chromosome.Abstract:
The genes controlling synthesis of Shigella flexneri group- and type-specific antigens were transferred to Escherichia coli K-12 recipients by conjugation with an S. flexneri Hfr. After mating E. coli with an Hfr strain of S. flexneri 2a and selecting for his+ recombinants, a high proportion of the E. coli hybrids agglutinated in S. flexneri grouping serum. None of these hybrids expressed S. flexneri type-specific antigen II. When an E. coli his+ hybrid possessing the S. flexneri group antigen was remated with the same Hfr with selection for pro+ hybrids, a high proportion now expressed the type-specific antigen as well as the previously inherited group antigen. If such crosses were performed in reverse order (i.e., pro+ followed by his+ selection), a different pattern of serological behavior was observed. None of the pro+ hybrids showed the type-specific antigen. Subsequent mating for his+ resulted in hybrids with both the group- and type-specific antigens. These results show that genes controlling the synthesis of S. flexneri group antigen (linked to the his locus) and type-specific antigen (linked to the pro locus) are widely separated on the chromosome. Expression of the type-specific antigen II depends on the presence of the group antigen.read more
Citations
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Production of Shigella dysenteriae Type 1-Like Cytotoxin by Escherichia coli
TL;DR: Strains of Escherichia coli previously implicated or proven to be causes of diarrhea were examined for production of a toxin similar to that of Shigella dysenteriae type 1 (Shiga), suggesting that Shiga-like toxin may be another heretofore undiscovered factor in the pathogenesis of diarrhea caused by some E. coli strains.
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“Black holes” and bacterial pathogenicity: A large genomic deletion that enhances the virulence of Shigella spp. and enteroinvasive Escherichia coli
TL;DR: These results suggest that, as Shigella spp.
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Genetic basis of virulence in Shigella species.
TL;DR: Shigella species and enteroinvasive strains of Escherichia coli cause disease by invasion of the colonic epithelium, and this invasive phenotype is mediated by genes carried on 180- to 240-kb plasmids, which can be classified as virulence determinants and cytotoxins.
Journal ArticleDOI
Histone-like protein H1 (H-NS), DNA supercoiling, and gene expression in bacteria
Christopher S.J. Hulton,Alexander Seirafi,Jay C. D. Hinton,Julie M. Sidebotham,Lesley Waddell,Graham D. Pavitt,Tom Owen-Hughes,Annick Spassky,Henri Buc,Christopher F. Higgins +9 more
TL;DR: It is shown that the product of the osmZ gene is the "histone-like" protein H1 (H-NS), one of the most abundant components of bacterial chromatin and binds to DNA in a relatively nonspecific fashion, providing support for the notion that changes in DNA topology and/or chromatin structure play a role in regulating gene expression.
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Molecular keys to speciation: DNA polymorphism and the control of genetic exchange in enterobacteria
TL;DR: The results reported here reveal that genetic barriers can be established, eliminated, or modified by manipulating two systems which control genetic recombination, SOS and mismatch repair.
References
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Journal ArticleDOI
Hybridization between Escherichia coli and Shigella.
TL;DR: It is established that these two types of intestinal bacteria could mate and produce hybrids possessing characteristics of each, and this had implications for laboratory diagnosis, raising the possibility that a hybrid possessing Shigella's pathogenic qualities could test as an E. coli, or vice-versa.
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Biosynthesis of bacterial lipopolysaccharide. I. Enzymatic incorporation of galactose in a mutant strain of Salmonella.
TL;DR: An enzyme system is described, derived from a mutant strain of S. typhimurium, which appears to be involved in the biosynthesis of the cellwall lipopolysaccharide, which is distinguished from the wild type by the absence of galactose as well as certain other components of the normal polysaccharides.
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Abortive intestinal infection with an escherichia coli-shigella flexneri hybrid strain.
TL;DR: It is concluded that the virulence of dysentery bacilli rests not only in the capacity to reach the lamina propria, but also in the ability to multiply in this region.