ABSTRACT
The restriction map of Yersinia pseudotuberculosis plasmid pVM82 was established using the "chromosome walking" method. According to transpositional mutagenesis, the plasmid pVM82 appeared to be conjugative and was able to be transmitted from Y. pseudotuberculosis to the E. coli K-12 cells.
Subject(s)
Plasmids , Yersinia pseudotuberculosis/genetics , Cloning, Molecular , Conjugation, Genetic , DNA Transposable Elements , DNA, Bacterial/genetics , Deoxyribonuclease HindIII , Escherichia coli/genetics , Genetic Markers , Nucleic Acid Hybridization , Restriction Mapping , Yersinia pseudotuberculosis/pathogenicityABSTRACT
Population of atoxigenic Eltor vibrios (vct-) isolated from open water has been shown to be heterogeneous by the genomic fingerprinting technique. Epidemically dangerous strains (vct+) containing the gene coding for cholera toxin have similar hybridization profile independent of time and place of their isolation. The clonal formation of vct+ strains and the absence of vct----vct+ transition of strains under natural conditions are discussed.
Subject(s)
DNA, Bacterial/analysis , Polymorphism, Genetic , Vibrio cholerae/genetics , Nucleic Acid Hybridization , Nucleotide MappingABSTRACT
Electrophoresis in agarose gel has been used to study the plasmid spectra of 854 Yersinia pseudotuberculosis strains isolated from different sources. The plasmids found in the microbial strains are represented by the elements with molecular masses 82; 57; 45; 5.5; 4.4; 3.5; 2.7; 2.4; 2.3 Md. The variable spectra of plasmids is peculiar only for serovar I of Yersinia pseudotuberculosis. Plasmids p45 and p82 are classified as the main, while other plasmids as auxiliary ones. In accord with the classification all plasmid containing strains are divided into 8 plasmid strains. Using the proposed method for intraspecific typing of Yersinia pseudotuberculosis permits one to perfect the epidemiological analysis of pseudotuberculosis infection and make concrete the direction of prophylactic and antiepidemic measures.
Subject(s)
Yersinia Infections/genetics , Yersinia pseudotuberculosis Infections/genetics , Yersinia pseudotuberculosis/genetics , Animals , Genes, Bacterial , Humans , Plasmids , Yersinia pseudotuberculosis/isolation & purification , Yersinia pseudotuberculosis Infections/microbiologyABSTRACT
Using the technique of the genes probes the naturally occuring strains Y. pseudotuberculosis and Y. enterocolitica of epidemiological importance were shown to contain pCad plasmid integrated with the chromosome. The strains having integrated plasmid express all pathogenicity determinants necessary for realization of infectious process.
Subject(s)
Calcium/pharmacology , Plasmids , Recombination, Genetic , Yersinia enterocolitica/pathogenicity , Yersinia pseudotuberculosis/pathogenicity , Chromosomes, Bacterial , Restriction Mapping , Yersinia enterocolitica/genetics , Yersinia pseudotuberculosis/geneticsABSTRACT
The strains of Yersinia pseudotuberculosis isolated from patients in the course of outbreaks of infection (epidemic strains) were found to possess at least two plasmids with molecular masses of 45 and 82 MD. In contrast, the strains obtained in sporadic cases harbored different sets of plasmids, but never the 82 MD plasmids. These plasmids designated pVM82 and isolated from strains of different geographic regions of the country were identical. pVM82 have no homology with Y. pestis plasmids of the similar size coding for the FraI antigen. The pVM82 DNA was found to be composed of the 57 MD plasmid DNA and the 25 MD fragment of Y. pseudotuberculosis DNA. Using Western blot hybridization technique it was shown that the presence of pVM82 suppressed formation of antibody against some major antigenic determinants of Y. pseudotuberculosis. Immunosuppression took place when the animals were infected with bacteria grown below 20 but not at 37 degrees C. The 57 MD plasmid failed to produce immunosuppression. It was concluded that the 25 MD fragment of pFN82 encoded a novel pathogenic factor responsible for immunosuppression.
Subject(s)
Genes, Bacterial , Plasmids , Yersinia pseudotuberculosis/pathogenicity , Antibodies, Bacterial/biosynthesis , Antigens, Bacterial/immunology , Electrophoresis, Agar Gel , Immunoblotting , Yersinia pseudotuberculosis/genetics , Yersinia pseudotuberculosis/immunologyABSTRACT
The clones with 4 to 30-fold increased level of tetracycline resistance (TcR) were selected from the strain of Escherichia coli K-12 carrying the pCO107 plasmid. The plasmid is the cointegrate formed from the plasmids pOX38 (F-derivative) and pCT105 (pBR322-derivative carrying the vct operon of Vibrio cholerae eltor and the RSI sequence). pCO107 contains RSI at the junctions of two plasmid genomes. Using restriction analysis and Southern blot hybridization technique it was shown that increased tetracycline resistance is accompanied by amplification of the pCT105 segment of pCO107 and depends upon the presence of direct repeats of flanking RSI. Amplification of the pCT105 also resulted in increased production of the cholerae toxin (CT).
Subject(s)
Cholera Toxin/genetics , DNA, Bacterial/genetics , Gene Amplification , Genes, Bacterial , Plasmids , Repetitive Sequences, Nucleic Acid , Tetracycline/antagonists & inhibitors , Vibrio cholerae/genetics , Base Sequence , Cholera Toxin/biosynthesis , Drug Resistance, Microbial/genetics , Escherichia coli/genetics , Genetic Markers , Nucleic Acid Hybridization , Vibrio cholerae/metabolismABSTRACT
Using the labeled DNA fragments containing the genes for cholera toxin the strains of cholera vibrios were studied for the presence of cholera toxin genes. Vibrio cholerae strains isolated from natural water reservoirs under the favourable epidemic situation do not contain the cholera toxin genes. The DNA hybridization method was compared with other methods used in research and practical work for estimation of epidemic importance of cholera vibrios.
Subject(s)
Cholera Toxin/genetics , DNA, Bacterial/genetics , Genes, Bacterial , Nucleic Acid Hybridization , Vibrio cholerae/genetics , Animals , Cloning, Molecular , Humans , Rabbits , Vibrio cholerae/pathogenicity , VirulenceABSTRACT
The structure of the cholera toxin operon and the location of A and B toxin subunits have been studied by the Southern blot hybridization on filters. The gene coding for the synthesis of the cholera toxin B-subunit has been cloned in the vector plasmid pBR322. The structural gene of A-subunit has been partially deleted by the restriction endonuclease Bal31 digestion. The size of the 250 b. p. deletion has been defined by electron microscopy. The production of the cholera toxin B-subunit in Escherichia coli K12 cells has been studied.