Proteolytic and oxidoreductase activity of Treponema denticola ATCC 35405 grown in an aerobic and anaerobic gaseous environment.

The cells of a human oral spirochete, Treponema denticola ATCC 35405, and of seven clinical isolates of this organism obtained from the subgingival dental plaque of periodontitis patients were studied for their ability to grow in an aerobic and an anaerobic environment, and for their profile of peptidohydrolase and oxidoreductase enzymes. The growth yield of aerobically grown cultures was either comparable to or higher than that of anaerobically grown ones regardless of whether prereduced broth, freshly prepared broth or oxidized broth was used. However, elimination of certain supplements from the growth media resulted in poor growth regardless of the nature of the gaseous environment. The microscopic morphology and motility of the cells were not affected by differences in the gaseous atmosphere. Quantitative studies on several peptidohydrolase activities suggest that anaerobically grown cells displayed higher specific activity especially toward N alpha-L-prolyl-2-naphthylamine, indicating that increased synthesis of proline iminopeptidase enzymes (or enzyme) of the cells was associated with anaerobic growth conditions. The formation of enzymes hydrolysing N alpha-benzoyl-DL-arginyl-2-naphthylamine (and the corresponding p-nitroaniline) was not affected to the same extent. Growth experiments suggest that T. denticola ATCC 35405 is a facultatively anaerobic spirochete instead of an obligate anaerobe as reported in previous literature. The quantitative enzyme studies suggest that the gaseous growth atmosphere of the cells can exert a selective effect on the activity levels of certain peptidolytic enzymes of this organism. Such effects were not observed when the whole cells were studied by means of qualitative or semi-quantitative enzyme tests. The activities of catalase, peroxidase and superoxide dismutase of the cells were low and variable. Because of this, it was not possible to relate these oxidoreductase activities to the composition of the gaseous atmosphere.