title: Oral Microbiome Metabolism: From "Who Are They?" to "What Are They Doing?".
abstract: Recent advances in molecular biology have facilitated analyses of the oral microbiome ("Who are they?"); however, its functions (e.g., metabolic activities) are poorly understood ("What are they doing?"). This review aims to summarize our current understanding of the metabolism of the oral microbiome. Saccharolytic bacteria-including Streptococcus, Actinomyces, and Lactobacillus species-degrade carbohydrates into organic acids via the Embden-Meyerhof-Parnas pathway and several of its branch pathways, resulting in dental caries, while alkalization and acid neutralization via the arginine deiminase system, urease, and so on, counteract acidification. Proteolytic/amino acid-degrading bacteria, including Prevotella and Porphyromonas species, break down proteins and peptides into amino acids and degrade them further via specific pathways to produce short-chain fatty acids, ammonia, sulfur compounds, and indole/skatole, which act as virulent and modifying factors in periodontitis and oral malodor. Furthermore, it is suggested that ethanol-derived acetaldehyde can cause oral cancer, while nitrate-derived nitrite can aid caries prevention and systemic health. Microbial metabolic activity is influenced by the oral environment; however, it can also modify the oral environment, enhance the pathogenicity of bacteria, and induce microbial selection to create more pathogenic microbiome. Taking a metabolomic approach to analyzing the oral microbiome is crucial to improving our understanding of the functions of the oral microbiome.
authors.affiliation: Division of Oral Ecology and Biochemistry, Tohoku University Graduate School of Dentistry, Sendai, Japan nobu-t@dent.tohoku.ac.jp nobuhiro.takahashi.a5@tohoku.ac.jp.
authors.forename: N
authors.initials: N
authors.lastname: Takahashi
mesh_terms: D001419:Bacteria / Q000378:metabolism; D003731:Dental Caries / Q000382:microbiology; D003773:Dental Plaque / Q000382:microbiology; D006801:Humans; D064307:Microbiota / Q000502:physiology; D009055:Mouth / Q000378:metabolism / Q000382:microbiology*; D009909:Oral Health; D010510:Periodontal Diseases / Q000382:microbiology
keywords: amino acid; carbohydrate; dental caries; oral biofilm; oral malodor; periodontal diseases