Escherichia coli heat-labile enterotoxin was synthesized in a cell-free system directed by DNA of the plasmid P307. Synthesis of the toxin, assayed by the elongation induced in Chinese hamster ovary cells, was strongly stimulated by cyclic AMP and occurred at physiological levels of Mg2+ only when the polyamine spermidine was present. Activity was abolished by heat and antisera prepared against...

Cholera toxin (CT) and the heat-labile enterotoxin of E. coli (LT), as well as their non toxic mutants, are potent mucosal adjuvants of immunization eliciting mucosal and systemic responses against unrelated co-administered antigens in experimental models and in humans (non toxic mutants). These enterotoxins are composed of two subunits, the A subunit, responsible for an ADP-ribosyl transferase...

background: rotaviruses (rv) are important viral diarrheal agents in calves. vaccination is an optimum measure to prevent bovine rotaviruses (brv) infection. however, little research on brv vp7 vaccine has been done and currently there is no brv vaccine. objective: to prepare a subunit vaccine of brv and investigate its efficacy. methods: total rna was extracted from ma104 cells infected with b...

The genes for a new enterotoxin were cloned from Escherichia coli SA53. The new toxin was heat labile and activated adenylate cyclase but was not neutralized by antisera against cholera toxin or E. coli heat-labile enterotoxin. Subcloning and minicell experiments indicated that the toxin is composed of two polypeptide subunits that are encoded by two genes. The two toxin subunits exhibited mobi...

BACKGROUND Enterotoxigenic Escherichia coli (ETEC) strains are the major causes of diarrheal disease in humans and animals. Colonization factors and enterotoxins are the major virulence factors in ETEC pathogenesis. For the broad-spectrum protection against ETEC, one could focus on colonization factors and non-toxic heat labile as a vaccine candidate. METHODS A fusion protein is composed of a...

the aim of this study was to determine the frequency of enterotoxigenic and enteroaggregative strains ofescherichia coli in chicken carcasses by polymerase chain reaction (pcr). in this study 63 strains of e. coliwere isolated from 110 samples of chicken carcasses during processing after chilling in the poultry slaughterhouse of shahrekord. polymerase chain reaction assays were used to detect t...

The aim of this study was to determine the frequency of enterotoxigenic and enteroaggregative strains ofEscherichia coli in chicken carcasses by polymerase chain reaction (PCR). In this study 63 strains of E. coliwere isolated from 110 samples of chicken carcasses during processing after chilling in the poultry slaughterhouse of Shahrekord. Polymerase chain reaction assays were used to detect t...

Heat-labile enterotoxins from Escherichia coli strains of porcine and human origin polymerize on heating to form high-molecular-weight aggregates, "procoligenoids," analogous to procholeragenoid derived from the cholera enterotoxin. This aggregation is accompanied by loss of biological activity (toxicity). Further heating results in the release of B-subunit oligomers, coligenoids, analogous to ...