title: A 28,000 mol. wt toxin from Bacillus thuringiensis israelensis induces cation transport in rat muscle cultures.
abstract: The mechanism by which the Bacillus thuringiensis israelensis (Bti) 28,000 mol. wt toxin exerts its effect on mature muscle cultures was examined. The toxin inhibited Na+/K(+)-ATPase activity as revealed by 86Rb influx. A 50% inhibition of Na+/K(+)-ATPase activity was obtained with 0.2 microgram/ml of the toxin. The inhibition was time and dose dependent, and it was reversible with low doses of the toxin (up to 0.2 microgram/ml. A considerable release of 86Rb was obtained by doses greater than 0.2 microgram/ml. The 86Rb release was also time and dose dependent. This effect is probably non-specific, since 45Ca influx is also accelerated by toxin-treated cultures. Pre-incubation of the toxin with phosphotidylserine (PS) antagonized the toxin. It is concluded that the toxin is a hydrophobic protein which interacts with the membrane. In low doses this interaction reduces the activity of the sodium pump and in high doses it causes non-specific permeability of the sarcolemma.
authors.affiliation: Health Science Research Center, Bar-Ilan University, Ramat Gan, Israel.
authors.forename: R
authors.initials: R
authors.lastname: Cahan
authors.forename: A
authors.initials: A
authors.lastname: Shainberg
authors.forename: I
authors.initials: I
authors.lastname: Pechatnikov
authors.forename: Y
authors.initials: Y
authors.lastname: Nitzan
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000737:chemistry*; D001427:Bacterial Toxins / Q000737:chemistry / Q000494:pharmacology*; D002478:Cells, Cultured; D016623:Ion Pumps / Q000187:drug effects*; D008970:Molecular Weight; D009132:Muscles / Q000187:drug effects* / Q000201:enzymology; D051381:Rats; D000254:Sodium-Potassium-Exchanging ATPase / Q000187:drug effects
chemical_list: D001427:Bacterial Toxins; D016623:Ion Pumps; D000254:Sodium-Potassium-Exchanging ATPase