INDUCTION OF LACTOSE UTILIZATION IN STAPHYLOCOCCUS AUREUS.

McClatchy, J. K. (The University of Texas, Dallas), and E. D. Rosenblum. Induction of lactose utilization in Staphylococcus aureus. J. Bacteriol. 86:1211-1215. 1963.-Adaptation to the utilization of lactose by Staphylococcus aureus has been compared with that by Escherichia coli. Lactose and galactose were found to be efficient inducers of the beta-galactosidase and the postulated galactoside-permease of S. aureus; the thiogalactosides, active as gratuitous inducers for E. coli, were inactive and inhibited induction of staphylococci by lactose and galactose. Mutants lacking beta-galactosidase or galactoside-permease, as well as a constitutive mutant for lactose utilization, were isolated. Like that in E. coli, the genetic system of staphylococcus seems to consist of two structural genes for the synthesis of the two enzymes and at least one regulatory gene simultaneously controlling the expression of the structural genes. The mutants were grouped by cross-transduction studies in three loci corresponding to the three phenotypes. Mutants of the pleiotropic locus were also isolated.