title: Ultrastructure and enzyme activities of a virulent and an avirulent variant of Bacteroides gingivalis W50.
abstract: The ultrastructure and enzyme activity of an avirulent, weakly-pigmenting, colonial variant (W50/BE1) was compared with that of the highly-virulent parent strain, Bacteroides gingivalis W50, in an attempt to identify significant virulence factors. Electron microscopy of thin sections of the organisms showed strain W50 to possess a 3-4-fold thicker layer of material external to the outer membrane. No significant differences between the strains were found with respect to collagen- or hyaluronic acid-breakdown activities at assay pH 7.5. However, cultures of strain W50 had over 3-fold more trypsin-like activity (P less than 0.01) than the avirulent variant. These results, when taken with other data, suggest that a thick external layer on the cell surface together with high trypsin-like activity might be important virulence factors of B. gingivalis.
authors.affiliation: Pathology Division, PHLS Centre for Applied Microbiology and Research, Salisbury, U.K.
authors.forename: P D
authors.initials: PD
authors.lastname: Marsh
authors.forename: A S
authors.initials: AS
authors.lastname: McKee
authors.forename: A S
authors.initials: AS
authors.lastname: McDermid
authors.forename: A B
authors.initials: AB
authors.lastname: Dowsett
mesh_terms: D001439:Bacteroides / Q000201:enzymology / Q000472:pathogenicity / Q000648:ultrastructure*; D010587:Phagocytosis; D014357:Trypsin / Q000032:analysis; D014774:Virulence
chemical_list: D014357:Trypsin