Showing papers on "Shigella dysenteriae published in 1982"

Production of Shigella dysenteriae Type 1-Like Cytotoxin by Escherichia coli

Abstract: 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). Organisms grown in an iron-depleted broth were lysed by pressure disruption followed by ultracentrifugation. Saline-dialyzed extracts were tested for cytotoxic effects on HeLa cells that were neutralizable with antiserum to Shiga toxin. Among the 13 E. coli strains so analyzed, 11 made a Shiga-like cytotoxin in levels ranging from trace (two avirulent isolates) to amounts equivalent to S. dysenteriae type 1 (two noninvasive strains that did not make E. coli heat-labile or -stable enterotoxins but were isolated from infants with diarrhea). As with extracts of Shiga toxin, lysates of these E. coli strains that produced high levels of Shiga-like toxin were enterotoxic for rabbits, paralytic and lethal for mice, and inhibited protein synthesis in HeLa cells. Thus, these data suggest that Shiga-like toxin may be another heretofore undiscovered factor in the pathogenesis of diarrhea caused by some E. coli strains.

Purification and Biological Characterization of Shiga Toxin from Shigella dysenteriae 1

Abstract: Shiga toxin has been purified in milligram quantities to near homogeneity from cell lysates of Shigella dysenteriae 1 strain 3818-0. Purification involved an initial ultracentrifugation, ammonium sulfate fractionation, chromatography on DEAE-cellulose and carboxymethyl cellulose, gel filtration, and preparative isoelectric focusing in sucrose gradients. The purified toxin was resolved by discontinuous polyacrylamide gel electrophoresis into a major cytotoxic protein band and a closely migrating, cytotoxic protease-nicked minor band. Antiserum generated by immunization with glutaraldehyde-inactivated toxin was shown to be monospecific against S. dysenteriae cell lysates. This highly purified toxin was cytotoxic to HeLa cells, enterotoxic in rabbit ileal loops, and lethal to mice. Monospecific antiserum to the toxin neutralized completely these toxin activities in both purified toxin preparations and crude shigella cell lysates.

Immunochemical and cytotoxic activities of Shigella dysenteriae 1 (shiga) and shiga-like toxins.

Abstract: Toxins in culture supernatants and bacterial lysates of S. dysenteriae 1 and S. flexneri were quantitated by a cytotoxicity assay and a newly developed radioimmunoassay. Cytotoxin titers paralleled toxin antigen levels. Thus, variations in cytotoxicity among shigellae probably reflect differences in toxin yield rather than specific activity (cytotoxicity per microgram of toxin antigen).

The nucleotide sequence coding for major outer membrane protein OmpA of Shigella dysenteriae

Abstract: The nucleotide sequence of the ompA gene from Shigella dysenteriae has been determined and the amino acid sequence of the pro-OmpA protein predicted. Sequence comparison between the ompA genes of S.dysenteriae and Escherichia coli showed that features such as mRNA secondary structure and codon usage, as well as polypeptide function, have been conserved during evolution. The pro-OmpA protein of S.dysenteriae consists of 351 residues, as opposed to the 346 of the E.coli protein and also shows several amino acid changes. These changes have been used to interpret differences in the biological activity of the two proteins.

Cloning and expression in Escherichia coli K-12 of the genes for major outer membrane protein OmpA from Shigella dysenteriae, Enterobacter aerogenes, and Serratia marcescens.

Abstract: The outer membranes of many gram-negative bacteria contain a major heat-modifiable protein which shows serological cross-reactivity with the OmpA protein of Escherichia coli K-12. Using the cloned gene for the E. coli K12 protein as a DNA-DNA hybridization probe, we were able to identify the corresponding genes from Shigella dysenteriae. Enterobacter aerogenes, and Serratia marcescens. These were cloned in a phage lambda vector, and their expression in E. coli K-12 was studied. All three OmpA proteins were fully produced and correctly exported to the outer membrane. In several cases, complete or partial restoration of known function of the E. coli K-12 protein was observed.

Increase in drug resistance among Shigella dysenteriae, Sh flexneri, and Sh boydii.

Abstract: To the authors' knowledge (information given by Cheltenham Drug Squad) this preparation after nine months has not found its way on to the black market outside of the Cheltenham area. Only one addict has admitted trying to inject the mixture: she concluded that it was "impossible," and she has not tried doing this again. Thus it would appear that this new dipipanone mixture has considerable advantages over any other opiate preparation currently being prescribed to maintain drug addicts.

Expression in Escherichia coli K12 of the cloned genes for a major outer membrane protein (OmpA protein) from Shigella dysenteriae, Enterobacter aerogenes and Serratia marcescens.

Abstract: Mots-clefs: Cloning, Molecular ; Genes, Bacterial Reference EPFL-ARTICLE-151381Afficher la publication dans PubMed Notice creee le 2010-09-07, modifiee le 2017-05-12