Intraoral Microbial Metabolism and Association with Host Taste Perception

Area of Science:

• Microbiology
• Metabolomics
• Oral Health

Background:

• Metabolomics offers functional insights into microbial communities, yet its application to the oral microbiome is limited.
• Understanding host-microbiome interactions in the mouth is crucial for oral health.
• Existing knowledge gaps concern the metabolic interplay between oral microbes and their human host.

Purpose of the Study:

• To investigate metabolic differences in oral microbial communities utilizing endogenous (salivary protein) and exogenous (dietary carbohydrates) substrates.
• To explore the association between microbial metabolite generation and host taste perception.
• To characterize the metabolic activity of oral biofilms and planktonic bacteria.

Main Methods:

• Nuclear magnetic resonance (NMR) spectroscopy was employed to analyze metabolic profiles.
• Oral microbial metabolism was studied using both salivary protein and sucrose as substrates.
• Metabolite concentrations were compared between tongue biofilms and planktonic salivary bacteria.

Main Results:

• Oral bacteria catabolize salivary protein, producing acetate, butyrate, and propionate, especially in tongue biofilms.
• In the presence of sucrose, glycolysis metabolites (lactate, pyruvate, succinate) and pyruvate derivatives (acetoin, alanine) increased.
• Individual sweet taste sensitivity correlated with sucrose metabolism, with high-sensitivity perceivers favoring citric acid cycle activity and low-sensitivity perceivers favoring lactate production.

Conclusions:

• The oral microbiome exhibits dynamic metabolic activity influenced by nutrient availability, maintaining a complex balance with the host.
• Metabolite production by oral bacteria, particularly near taste receptors, can reach significant concentrations.
• Preliminary evidence suggests a link between host sweet taste perception and the oral microbial catabolism of sugar.