]> 2026-07-31T16:29:22+00:00 WBR0300 0 en ''Pseudomonas aeruginosa'' exotoxin A ''Vibrio cholerae'' exotoxin The ''Vibrio cholerae'' exotoxin is part of a group of bacterial toxins referred to as A/B toxins, owing to the presence of 2 subunits. The toxin is responsible for the massive, watery diarrhea characteristic of cholera infection. It acts by causing ATP-mediated efflux of chloride ions into the gut lumen. The ''Vibrio cholerae'' exotoxin is usually inactivated by heating at 60 °C (140 °F) for several minutes. Staphylococcal enterotoxin B Staphylococcal enterotoxin B is unique among exotoxins for being very heat stable. It is able to withstand extreme temperatures as high as 100 °C (212 °F) for several minutes. Tetanospasmin ''Bordetella pertussis'' exotoxin The ''Bordetella pertussis'' exotoxin is also an A/B toxin that acts by binding the G_i subunit of G protein-coupled receptors (GPCRs). The binding process disables the inhibition of adenylyl cyclase activity, leading to increased concentrations of cyclic AMP (cAMP). The ''Bordetella pertussis'' exotoxin is usually inactivated by heating at 60 °C (140 °F) for several minutes. Microbiology After isolating and purifying several bacterial toxins using thiol-disulfide exchange affinity chromatography, a researcher studying the properties of bacterial toxins exposes the purified product to a number of harsh conditions. In one experiment, he heats the product to 70 °C (158 °F) and then injects a sample into anesthetized rats. Which of the following bacterial toxins is likely to elicit symptoms following injection? C General Principles 2020-10-28T00:06:53Z 2459150.5047801 WBR0300