Construction and characterization of isogenic mutants of Streptococcus mutans deficient in major surface protein antigen P1 (I/II).

摘要: The gene (spaP) coding for the Streptococcus mutans major surface protein antigen P1 (or I/II) has been cloned into Escherichia coli (S. F. Lee, A. Progulske-Fox, and S. Bleiweis, Infect. Immun. 56:2114-2119, 1988). In present study, this disrupted in vitro by insertional inactivation with pVA981, which carries a Tcr marker, transformed NG8 (serotype c) electroporation. Upon homologous recombination, defective spaP was integrated genome as demonstrated Southern hybridization analysis. One mutant, designated 834, selected its nonreactivity anti-P1 monoclonal antibodies, found to lack cell fuzzy layer clearly on parent cells. Analysis of extracellular fluids, sodium dodecyl sulfate-solubilized membranes, cytoplasmic fractions sulfate-polyacrylamide gel electrophoresis showed that 834 had profiles identical parent. However, 185-kilodalton reacts antibodies missing from wall suggesting specifically inactivated. This mutant displayed levels glucosyltransferase fructosyltransferase activities similar those It much less hydrophobic than aggregated readily presence clarified whole saliva or high-molecular-weight salivary agglutinin. strain also adhered agglutinin-coated hydroxyapatite. P1-negative mutants, however, did not display these two properties, may play role saliva-mediated aggregation adherence.