Molecular characterization of a locus required for hyaluronic acid capsule production in group A streptococci.

摘要: To characterize the production of hyaluronate capsule by membrane-associated enzyme synthase (HAS), group A streptococci from a recent outbreak acute rheumatic fever were mutagenized via Tn916 insertion. Acapsular transconjugants harboring multiple, nontandem copies transposon identified and found to lack HAS activity (less than 1% wild-type levels). Generalized transduction was then performed determine which insertion responsible for HAS- phenotype. These marker exchange experiments resulted in isolation two distinct classes acapsular transductants, designated WF61 WF62. Both transductants also lacked significant activity, excision WF62 restored capsular production. Southern analysis DNA demonstrated large deletion genomic adjacent This event is presumably observed stability phenotype WF61. Further analyses transductant whole-cell indicated that insertions separated 2.5 kb. studies define locus required streptococci. genetic this has gene wasd inactivated TN916 deleted