title: Production and characterization of two hemolysins of Bacillus cereus.
abstract: Bacillus cereus strain B-48 produced two hemolysins with molecular weights of 52,000 (H-I) and 31,000 (H-II). A mutant was isolated that produced only H-II but was identical with the wild type in all other respects. We exploited this mutant to produce H-II for study that was free of contamination by H-I. By manipulation of media composition, we produced H-I in the absence of H-II. The hemolysins were precipitated differently by ammonium sulfate, and both exhibited the Arrhenius effect when heated. Both hemolysins attached rapidly to erythrocytes; however, lysis by H-I was immediate, while lysis by H-II followed after a lag. Hemolysis by H-I and H-II increased in rate with increasing temperature and was absent at 0 degrees C. Only H-I was inhibited by cholesterol. The hemolysins of B. cereus appeared similar to the hemolysins of B. thuringiensis. H-I probably is identical with cereolysin.
mesh_terms: D000818:Animals; D001409:Bacillus cereus / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D004912:Erythrocytes / Q000276:immunology; D006460:Hemolysin Proteins / Q000096:biosynthesis* / Q000276:immunology; D006461:Hemolysis; D008970:Molecular Weight; D009154:Mutation; D011817:Rabbits; D013696:Temperature
chemical_list: D006460:Hemolysin Proteins