Biochemical genetics of the cryptic gene system for @entity8692 utilization in XXXX .

@entity33636 @entity7954 @entity21085 @entity28294 @entity8692 @entity2624 @entity3363
The @entity8692 catabolic system of @entity2624 is being used to study the role of cryptic genes in microbial evolution. Wild-type @entity2624 do not utilize the beta-glucoside @entity3363 , @entity33636 , @entity28294 and @entity8692 . A Cel+ ( @entity8692 utilizing) mutant which grows on @entity8692 , @entity33636 , and @entity28294 was isolated previously from wild-type @entity2624 . Biochemical assays indicate that a cel structural gene (celT) specifies a single transport protein that is a beta-glucoside specific enzyme of the @entity7954 -dependent phosphotransferase system. The transport protein phosphorylates beta-glucosides at the expense of phosphoenolpyruvate. A single phosphoglucosidase, specified by celH, hydrolyzes phosphorylated @entity8692 , @entity33636 , and @entity28294 . The genes of the cel system are expressed constitutively in the Cel+ mutant, whereas they are not expressed at a detectable level in the wild-type strain. The transport and hydrolase genes are simultaneously silenced or simultaneously expressed and thus constitute an operon. Cel+ strains which fail to utilize one or more beta-glucosides express the transport system at a lower level than do Cel+ strains which grow on all three beta-glucosides. Other strains inducibly express a gene which specifies transport of @entity33636 but not the other @entity21085 . The @entity33636 transport gene, arbT, maps outside of the cel locus.
