{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,22]],"date-time":"2026-10-22T15:58:37Z","timestamp":1792684717647,"version":"4.5.0"},"reference-count":33,"publisher":"Public Library of Science (PLoS)","issue":"12","license":[{"start":{"date-parts":[[2023,12,21]],"date-time":"2023-12-21T00:00:00Z","timestamp":1703116800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS ONE"],"abstract":"<jats:p>The nitrate (NO<jats:sub>3<\/jats:sub><jats:sup>-<\/jats:sup>) reducing bacteria resident in the oral cavity have been implicated as key mediators of nitric oxide (NO) homeostasis and human health. NO<jats:sub>3<\/jats:sub><jats:sup>-<\/jats:sup>-reducing oral bacteria reduce inorganic dietary NO<jats:sub>3<\/jats:sub><jats:sup>-<\/jats:sup> to nitrite (NO<jats:sub>2<\/jats:sub><jats:sup>-<\/jats:sup>) via the NO<jats:sub>3<\/jats:sub><jats:sup>-<\/jats:sup>-NO<jats:sub>2<\/jats:sub><jats:sup>-<\/jats:sup>-NO pathway. Studies of oral NO<jats:sub>3<\/jats:sub><jats:sup>-<\/jats:sup>-reducing bacteria have typically sampled from either the tongue surface or saliva. The aim of this study was to assess whether other areas in the mouth could contain a physiologically relevant abundance of NO<jats:sub>3<\/jats:sub><jats:sup>-<\/jats:sup> reducing bacteria, which may be important for sampling in clinical studies. The bacterial composition of seven oral sample types from 300 individuals were compared using a meta-analysis of the Human Microbiome Project data. This analysis revealed significant differences in the proportions of 20 well-established oral bacteria and highly abundant NO<jats:sub>3<\/jats:sub><jats:sup>-<\/jats:sup>-reducing bacteria across each oral site. The genera included <jats:italic>Actinomyces<\/jats:italic>, <jats:italic>Brevibacillus<\/jats:italic>, <jats:italic>Campylobacter<\/jats:italic>, <jats:italic>Capnocytophaga<\/jats:italic>, <jats:italic>Corynebacterium<\/jats:italic>, <jats:italic>Eikenella<\/jats:italic>, <jats:italic>Fusobacterium<\/jats:italic>, <jats:italic>Granulicatella<\/jats:italic>, <jats:italic>Haemophilus<\/jats:italic>, <jats:italic>Leptotrichia<\/jats:italic>, <jats:italic>Microbacterium<\/jats:italic>, <jats:italic>Neisseria<\/jats:italic>, <jats:italic>Porphyromonas<\/jats:italic>, <jats:italic>Prevotella<\/jats:italic>, <jats:italic>Propionibacterium<\/jats:italic>, <jats:italic>Rothia<\/jats:italic>, <jats:italic>Selenomonas<\/jats:italic>, <jats:italic>Staphylococcus<\/jats:italic>, <jats:italic>Streptococcus<\/jats:italic> and <jats:italic>Veillonella<\/jats:italic>. The highest proportion of NO<jats:sub>3<\/jats:sub><jats:sup>-<\/jats:sup>-reducing bacteria was observed in saliva, where eight of the bacterial genera were found in higher proportion than on the tongue dorsum, whilst the lowest proportions were found in the hard oral surfaces. Saliva also demonstrated higher intra-individual variability and bacterial diversity. This study provides new information on where samples should be taken in the oral cavity to assess the abundance of NO<jats:sub>3<\/jats:sub><jats:sup>-<\/jats:sup>-reducing bacteria. Taking saliva samples may benefit physiological studies, as saliva contained the highest abundance of NO<jats:sub>3<\/jats:sub><jats:sup>-<\/jats:sup> reducing bacteria and is less invasive than other sampling methods. These results inform future studies coupling oral NO<jats:sub>3<\/jats:sub><jats:sup>-<\/jats:sup>-reducing bacteria research with physiological outcomes affecting human health.<\/jats:p>","DOI":"10.1371\/journal.pone.0295058","type":"journal-article","created":{"date-parts":[[2023,12,21]],"date-time":"2023-12-21T18:54:39Z","timestamp":1703184879000},"page":"e0295058","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":15,"title":["Localisation of nitrate-reducing and highly abundant microbial communities in the oral cavity"],"prefix":"10.1371","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-8947-3132","authenticated-orcid":true,"given":"Joanna E.","family":"L\u2019Heureux","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1033-1335","authenticated-orcid":true,"given":"Mark","family":"van der Giezen","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9613-1202","authenticated-orcid":true,"given":"Paul G.","family":"Winyard","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andrew M.","family":"Jones","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Anni","family":"Vanhatalo","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2023,12,21]]},"reference":[{"issue":"11","key":"pone.0295058.ref001","doi-asserted-by":"crossref","first-page":"5721","DOI":"10.1128\/JCM.43.11.5721-5732.2005","article-title":"Defining the normal bacterial flora of the oral cavity","volume":"43","author":"JA Aas","year":"2005","journal-title":"J Clin Microbiol"},{"issue":"2","key":"pone.0295058.ref002","doi-asserted-by":"crossref","first-page":"136","DOI":"10.1111\/j.1601-0825.2009.01607.x","article-title":"Exploring the oral bacterial flora: current status and future directions","volume":"16","author":"NB Parahitiyawa","year":"2010","journal-title":"Oral Dis"},{"issue":"2","key":"pone.0295058.ref003","doi-asserted-by":"crossref","first-page":"156","DOI":"10.1038\/nrd2466","article-title":"The nitrate\u2013nitrite\u2013nitric oxide pathway in physiology and therapeutics","volume":"7","author":"JO Lundberg","year":"2008","journal-title":"Nature Reviews Drug Discovery"},{"issue":"33","key":"pone.0295058.ref004","doi-asserted-by":"crossref","first-page":"13434","DOI":"10.1073\/pnas.1116633109","article-title":"Sialin (SLC17A5) functions as a nitrate transporter in the plasma membrane.","volume":"109","author":"L Qin","year":"2012","journal-title":"Proc Natl Acad Sci U S A"},{"issue":"12","key":"pone.0295058.ref005","doi-asserted-by":"crossref","first-page":"865","DOI":"10.1038\/nchembio.260","article-title":"Nitrate and nitrite in biology, nutrition and therapeutics","volume":"5","author":"JO Lundberg","year":"2009","journal-title":"Nat Chem Biol"},{"issue":"1","key":"pone.0295058.ref006","doi-asserted-by":"crossref","first-page":"315","DOI":"10.1152\/physrev.00029.2006","article-title":"Nitric oxide and peroxynitrite in health and disease","volume":"87","author":"P Pacher","year":"2007","journal-title":"Physiol Rev"},{"issue":"1","key":"pone.0295058.ref007","doi-asserted-by":"crossref","first-page":"34","DOI":"10.1016\/j.niox.2010.10.002","article-title":"Acute effect of a high nitrate diet on brain perfusion in older adults","volume":"24","author":"TD Presley","year":"2011","journal-title":"Nitric Oxide"},{"key":"pone.0295058.ref008","doi-asserted-by":"crossref","first-page":"93","DOI":"10.1016\/j.freeradbiomed.2012.11.013","article-title":"Physiological role for nitrate-reducing oral bacteria in blood pressure control","volume":"55","author":"V Kapil","year":"2013","journal-title":"Free Radic Biol Med"},{"issue":"14","key":"pone.0295058.ref009","doi-asserted-by":"crossref","first-page":"2669","DOI":"10.1017\/S1368980015000038","article-title":"High-nitrate vegetable diet increases plasma nitrate and nitrite concentrations and reduces blood pressure in healthy women","volume":"18","author":"A Ashworth","year":"2015","journal-title":"Public Health Nutr"},{"issue":"12","key":"pone.0295058.ref010","doi-asserted-by":"crossref","first-page":"2317","DOI":"10.1101\/gr.096651.109","article-title":"The NIH Human Microbiome Project","volume":"19","author":"J Peterson","year":"2009","journal-title":"Genome Res"},{"key":"pone.0295058.ref011","doi-asserted-by":"crossref","first-page":"207","DOI":"10.1038\/nature11234","article-title":"Structure, function and diversity of the healthy human microbiome.","volume":"486","author":"Consortium. 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