Derivation of high enterotoxin B-producing mutants of Staphylococcus aureus from the parent strains.
Certain pH-sensitive (membrane) mutants of Staphylococcus aureus, strains 14458 and 778, produce significantly more type-B enterotoxin (SEB) than the parent type. Some carbohydrate mutants (car) from these parent strains also are superior to the parent in SEB formation. By isolating car mutants from high-SEB-producing membrane mutants, it is possible to derive a double mutant producing from six to 50 times as much SEB as the parent type. Inversion of the sequence by isolating pH-sensitive mutants from car mutants does not yield clones with strikingly higher SEB production than the parent strain. The successful isolation sequence (pH-sensitive mutant first and car mutants derived from it) is relatively simple and virtually assures detection of a truly high-SEB-producing clone. The total number of clones whose direct assay for SEB formation is necessary for detection of a high-producing mutant is on the order of 50 to 60.
D004768:Enterotoxins / Q000096:biosynthesis*; D005796:Genes; D008040:Genetic Linkage; D006863:Hydrogen-Ion Concentration; D009154:Mutation; D010641:Phenotype; D013211:Staphylococcus aureus / Q000302:isolation & purification / Q000378:metabolism*
D004768:Enterotoxins