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Paul J. Chuba Myron A. Leon Amit Banerjee Sunil Palchaudhuri 《Molecular & general genetics : MGG》1989,216(2-3):287-292
Summary
Escherichia coli K12 cells carrying a cloned 1.4 kb HindIII fragment from plasmid ColV2-K94, showed increased survival in guinea pig serum. The recombinant plasmid also conferred group II surface exclusion, i.e. the cells were reduced in recipient ability towards the incoming plasmid R538drd in conjugation experiments. Southern blotting suggested homology with bacteriophage lambda DNA and to the insertion element IS2. Determination of the DNA sequence of the fragment demonstrated the presence of a truncated IS2 (165 bp), separated by 250 bp from a 900 bp stretch of homology with lambda DNA, beginning within the Rz gene and continuing in the rightward direction on the lambda map. A 97 amino acid open reading frame (ORF) adjacent to Rz and on the opposite strand, remained intact in iss, with several amino acid changes. The ORF in iss is preceded by sequences resembling prokaryotic ribosome binding sites and promoters. 相似文献
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Amit Banerjee Peter C. Weber Sunil Palchaudhuri 《Molecular & general genetics : MGG》1990,220(2):320-324
Summary We have isolated a deletion mutation and a point mutation in the copB gene of the replication region Repl of the IncFI plasmid Co1V2-K94. Subsequently, this copB gene with and without point mutation was cloned and sequenced, and the point mutation was mapped in the coding region of copB with a change of one amino acid from arginine to serine. Furthermore, this copB mutant had an approximately 10-fold increase in copy number. The CopB-phenotype of Co1V2-K94 could be complemented in trans by the copB gene of coresident IncFII plasmids such as R1 and R538, but not R100, suggesting that ColV2-K94 and R1 or R538 contain the same copB allele. 相似文献
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Abstract The hydrophobicity of E. coli strains carrying or lacking the colicin V ( ColV ) plasmids, ColV , I-K94 or ColV -K30 was assayed. ColV + derivatives of strain 1829, produced by conjugation or transformation, were more hydrophobic than either the original 1829 parental strain or a Col - derivative formed by curing 1829 ColV -K30 of its plasmid by an SDS/high temperature growth technique. Transfer of ColV into other E. coli strains also led to increased hydrophobicity. This effect of ColV plasmids was observed for organisms grown at 37°C; ColV + and ColV- strains did not differ in hydrophobicity of grown at 21°C. This finding and other studies suggest that sex pili may be involved in the increased hydrophobicity. 相似文献
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Abstract Growth of wild-type strains and K-12 derivatives of Escherichia coli in calf serum was strongly enhanced by the iron(III) aerobactin supply system specified by certain ColV plasmids. Aerobactin was superior over enterochelin in stimulating growth. In contrast to enterochelin and ferrichrome, aerobactin seemed not to be hydrolyzed or modified during delivery of iron to cells. 相似文献
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A genotypic comparison using pulsed-field gel electrophoresis (PFGE), amplified ribosomal restriction analysis (ARDRA) as well as PCRs targeting virulence associated genes reported elsewhere in avian pathogenic Escherichia coli(APEC) was made between E. coli strains isolated from chickens with colibacillosis and those from the feces of apparently healthy chickens in Japan. The majority (67%) of clinical isolates belonged to a certain phylogenetic ARDRA but not PFGE cluster, with virulence-related genes carried by ColV plasmid being markedly prevalent. The result suggests that APEC strains originated from the same "ancestor" in the course of E. coli evolution. 相似文献
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