<prompt> Cholera toxin acts by which mechanism?Overactivates adenylate cyclase cAMP by permanently activating GsMimics the adenylate cyclase enzyme cAMPOveractivates guanylate cyclase cGMPInactivate elongation factor EF-2  <response>: Ans. a. Overactivates adenylate cyclase cAMP by permanently activating GsCholera toxin binds and activates Gs, resulting in very high levels of intracellular cAMP. This rise in cAMP opens luminal Cl- channels, causing a massive secretory diarrhea.TOXINS WITH A-B ADP-RIBOSYL TRANSFERASE ACTIVITYToxin ADP-Ribosylated Host ProteinEffect on Host CellPseudomonas Exotoxin SExotoxin A UnknowneEF-2Inhibits translocation during protein synthesisDiphtheria toxin eEF-2Inhibits translocation during protein synthesisE. coliHeat-labile toxin LTHeat-stable toxin STG-protein GSIncreases cAMP in intestinal epithelium causing diarrheaIncreases cGMP in, which decreases the resorption of NaCI and H20 in gutCholera toxin G-protein GSIncreases cAMP in intestinal epithelium causing diarrheaPertussis toxin G-protein GiIncreases cAMP causing edema, lymphocytosis and increased insulin secretionEdema toxin Mimics the adenylate cyclase enzyme Increases cAMPShiga toxin ST Inactivate 60S ribosome by removing adenine from rRNA 