FIG. 4.

Gas chromatographic patterns of VSCs produced by P. gingivalis W83 and M1217. (A) To measure the formation of methyl mercaptan, a reaction mixture consisting of 100 μl of the cell suspension of P. gingivalis (OD₅₅₀ of 0.3), 870 μl of the buffered salt solution, and 30 μl of 33 mM l-methionine was added to a tube, which was sealed with a silicon plug. The reaction mixtures were kept at 37°C for 90 min. The reaction was stopped by adding 500μl of 3 M phosphoric acid. Ten minutes later, the sample (1 ml) of the vapor above the reaction mixture in the tube was analyzed by gas chromatography. (B) VSCs in the vapor above 100 μl of the supernatants of the cultures of P. gingivalis strains in a sealed tube were determined by gas chromatography.