ODOUR PRODUCTION BY HUMAN SALIVARY FRACTIONS AND PLAQUE

The odour-producing activity of whole saliva, saliva sediment and supernate, and plaque was assessed on the basis of odour intensity, volatile oxidizable sulphur production, and hydrogen transfer activity. Studies on saliva fractions indicate that the cellular elements in the sediment are a primary source of participating enzymes. Saliva sediment exhibited only trace activity in the absence of supernate. This supernatefree sediment was still capable of producing intensely objectionable odour provided that the rate-limiting step is by-passed, as was demonstrated by the addition of cysteine. Heat-inactivated supernate completely restored the hydrogen transfer and most of the odour-producing activity of the viable sediment. In contrast, the activity of supernate in the absence of viable sediment or in the presence of heat-inactivated sediment was barely detectable within the time limits studied. The addition of cysteine failed to restore the odour production activity in these latter systems. Plaque exhibited a strong potential for odour production in the presence of appropriate substrates. While plaque inoculated into saliva supernate yielded only feeble activity, the addition of cysteine, cystine, and methionine markedly intensified odour and volatile sulphur compound production by these supplemented systems. Potent odour-producing activity was also demonstrated with plaque-inoculated synthetic test media. The amperometric and mass spectrometric analysis of volatile compositions revealed the presence of large concentrations of sulphur-containing compounds (hydrogen sulphide, methyl mercaptan, dimethyldisulphide, and sulphur dioxide) in the head-space of putrefied media systems. The evidence derived from these studies suggests that plaque and saliva elaborate similar malodorous products of putrefaction. © 1969.