We used Salmonella enteritidis serotype dublin strain SL1438, a nonreverting, aromatic-dependent, histidine-requiring mutant, as a recipient for a recombinant plasmid coding for production of the nontoxic B subunit of the heat-labile Escherichia coli enterotoxin. The S. enteritidis derivative EL23 produced heat-labile enterotoxin subunit B that was indistinguishable from heat-labile enterotoxin...

A cytolytic enterotoxin produced by Aeromonas hydrophila, isolate SSU, has been cloned in our laboratory. This enterotoxin lysed rabbit red blood cells, destroyed Chinese hamster ovary cells, caused fluid secretion in rat ligated ileal loops, inhibited the phagocytic function of mouse phagocytes, and was lethal to mice when injected intravenously. In this study, the effect of this cytolytic ent...

The sporulation-specific enterotoxin of Clostridium perfringens type A, which is the toxin active in human food poisoning, has been purified from extracts of sporulating cells. Highly purified enterotoxin was obtained by treatment of crude cell extract with ribonuclease for 30 min, followed by sequential chromatography on Sephadex G-100, Cellex T cellulose, and hydroxylapatite. Recovery was 65 ...

The biosynthesis of enterotoxin A by replicating and nonreplicating cells was investigated. Unlike enterotoxin B, a secondary metabolite, enterotoxin A secretion resembled that of a primary metabolite by being secreted during the exponential phase of growth. The amount of toxin produced per unit of growth was not influenced by NaCl, NaNO(2), or NaNO(3). Several surfactants increased toxin secre...

The ability of Clostridium perfringens type A to produce an enterotoxin active in human food poisoning has been shown to be directly related to the ability of the organism to sporulate. Enterotoxin was produced only in a sporulation medium and not in a growth medium in which sporulation was repressed. Mutants with an altered ability to sporulate were isolated from an sp(+) ent(+) strain either ...

The in vitro exposure of staphylococcal enterotoxin B to trypsin resulted in the formation within 30 min of a product (enterotoxin-T) unchanged in molecular weight, but with threonine as a second NH2 terminus. Upon reduction of the -SSbridge in enterotoxin-T, two fragments were separated by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. The peptide bond between Lys-97 and Thr-98 ...

We screened a panel of monoclonal antibodies against selected macrophage cell surface molecules for their ability to inhibit enterotoxin binding to major histocompatibility complex class II-negative C2D (H-2b) macrophages. Two monoclonal antibodies, HB36 and TIB126, that are specific for the alpha 2 domain of major histocompatibility complex class I, blocked staphylococcal enterotoxins A and B ...

The in vitro exposure of staphylococcal enterotoxin B to trypsin resulted in the formation within 30 min of a product (enterotoxin-T) unchanged in molecular weight, but with threonine as a second NH2 terminus. Upon reduction of the -SSbridge in enterotoxin-T, two fragments were separated by polyacrylamide gel electrophoresis in sodium dodecyl sulfate. The peptide bond between Lys-97 and Thr-98 ...

ABSTRACT: The aim of this study was to molecularly identify different species Aeromonas isolated from farmed tambaqui (Colossoma macropomum) North Brazil, and evaluate their pathogenic potential by the presence virulence genes. From extraction bacterial DNA, PCR (polymerase chain reaction) primers 16S rDNA, aerA (cytolytic enterotoxin), ast (cytotoxic enterotoxin) act were performed. Of 24 isol...

The quorum-sensing system of Staphylococcus aureus, the accessory gene regulator (Agr) system, is responsible for increased transcription of certain exoprotein genes and decreased transcription of certain cell wall-associated proteins during the postexponential phase of growth. This regulation is important for virulence, as evidenced by a reduction in virulence associated with a loss of the Agr...