Open AccessUltrastructure and enzyme activities of a virulent and an avirulent variant of Bacteroides gingivalis W50
Author(s) -
Marsh Philip D.,
McKee Ailsa S.,
McDermid Ann S.,
Barry Dowsett A.
Publication year - 1989
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1989.tb03106.x
Subject(s) - virulence , ultrastructure , microbiology and biotechnology , bacteroides , trypsin , bacterial outer membrane , strain (injury) , bacteroidaceae , enzyme , biology , secretion , virulence factor , bacteria , chemistry , biochemistry , gene , escherichia coli , anatomy , genetics
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 < 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 .