Potentiometric and spectrophotometric titrations of staphylococcal enterotoxin B have been carried out in 0.16 M KC1 at 25”. Potentiometric titration results indicate that the titration curves are essentially reversible between pH 1.50 and 11.0. All of the ionizable groups in enterotoxin B found from the titration curves are consistent with the amino acid composition which has been reported in ...

A commercial coagglutination assay (COA; Phadebact LT-ETEC) was compared with a Y1 mouse adrenal cell assay for detecting the heat labile enterotoxin of Escherichia coli. Of four different media evaluated for use with the COA, only one (modified blood agar) gave a positive result with all strains known to produce heat labile enterotoxin. With modified blood agar, the COA detected 74 (85%) of 87...

The purification procedure of Clostridium perfringens type A enterotoxin has been improved. The cell sonic extract was precipitated twice with ammonium sulfate, first 40% saturated to concentrate the enterotoxin and then 15% saturated. The two precipitations were followed by gel filtration on Sephadex G-100. The enterotoxin appeared to be homogeneous on 7% polyacrylamide gel electrophoresis aft...

Four synthetic oligonucleotides encoding different parts of the Clostridium perfringens enterotoxin gene were used to test the enterotoxigenicity of C. perfringens strains isolated from confirmed outbreaks of food poisoning. Of the 245 strains isolated from food and feces originating from 186 separate outbreaks, 145 (59%) gave hybridization reactions with each of the four DNA probes used, while...

Staphylococcus enterotoxin superantigens are potent T cell activators. To gain new insights into the mechanism of T cell activation induced by these superantigens, we investigated the recruitment of signaling molecules in this process. Here, we show that enterotoxin superantigen activation can be transmitted to TCR-CD3 complexes that did not interact with their ligand. Indeed, by studying cells...

By using a strain of Salmonella typhimurium, we detected the presence of an enterotoxin, as determined by the rabbit ileal loop assay, in various complex and defined media. The enterotoxin was concentrated by ultrafiltration of culture supernatant fluids and eluted in and adjacent to the void volume of a Sephadex G-100 column. This suggested that the enterotoxic factor was of a relatively high ...

Staphylococcal enterotoxin B is a potent mitogen for mouse and human lymphocytes. Mitogenic activity was retained after detoxification of the enterotoxin by formaldehyde at pH 5.0, 7.5, OR 9.5. The most active toxoid (pH 7.5) was separated into a monomeric, a dimeric, and a polymeric fraction (1 x 10(5) to 3 x 10(5) molecular weight) by gel filtration, and although each fraction demonstrated mi...

When axenic mice fed a commercial diet were monoassociated with two toxigenic strains of Clostridium difficile, 100% of them died 3 days after inoculation and both enterotoxin and cytotoxin were produced in their intestinal tract. However, when axenic mice were fed various semisynthetic diets before C. difficile challenge, some of them survived and their fecal cytotoxin and enterotoxin producti...

1. Dogs develop severe gastrointestinal symptoms in response to intraintestinal administration of staphylococcal enterotoxin. These symptoms are salivation, vomiting, and diarrhea. 2. Staphylococcal enterotoxin induces acute enteritis marked by edema, hyperemia, round cell infiltration, mucosal exudation, and destruction of intestinal villi. 3. Prolonged administration of enterotoxin into the l...

Bacteriocin AS-48 showed high bactericidal activity for mesophilic and psychrotrophic strains of Bacillus cereus over a broad pH range. AS-48 inhibition of the enterotoxin-producing strain LWL1 was enhanced by sodium nitrite, sodium lactate, and sodium chloride. The latter also enhanced AS-48 activity against strain CECT 131. Bacterial growth and enterotoxin production by strain LWL1 were compl...