{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"institution":[{"name":"bioRxiv"}],"indexed":{"date-parts":[[2026,4,12]],"date-time":"2026-04-12T08:52:52Z","timestamp":1775983972405,"version":"3.50.1"},"posted":{"date-parts":[[2025,3,31]]},"group-title":"Microbiology","reference-count":67,"publisher":"openRxiv","license":[{"start":{"date-parts":[[2025,3,31]],"date-time":"2025-03-31T00:00:00Z","timestamp":1743379200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"accepted":{"date-parts":[[2025,3,31]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                <jats:p>\n                  <jats:italic>Pseudomonas aeruginosa<\/jats:italic>\n                  causes acute and chronic infections such as those that occur in the lungs of people with cystic fibrosis (CF). In infection environments, oxygen (O\n                  <jats:sub>2<\/jats:sub>\n                  ) concentrations are often low. The transcription factor Anr responds to low O\n                  <jats:sub>2<\/jats:sub>\n                  by upregulating genes necessary for\n                  <jats:italic>P. aeruginosa<\/jats:italic>\n                  fitness in microoxic and anoxic conditions. Anr regulates\n                  <jats:italic>dnr<\/jats:italic>\n                  , a gene encoding a transcriptional regulator that promotes the expression of genes required for using nitrate as an alternative electron acceptor during denitrification. In CF sputum, transcripts involved in denitrification are highly expressed. While Dnr is necessary for the anoxic growth of\n                  <jats:italic>P. aeruginosa<\/jats:italic>\n                  in CF sputum and artificial sputum media (ASMi), the contribution of denitrification to\n                  <jats:italic>P. aeruginosa<\/jats:italic>\n                  fitness in oxic conditions has not been well described. Here we show that\n                  <jats:italic>P. aeruginosa<\/jats:italic>\n                  requires\n                  <jats:italic>dnr<\/jats:italic>\n                  for fitness in ASMi and the requirement for\n                  <jats:italic>dnr<\/jats:italic>\n                  is abolished when nitrate is excluded from the media. Additionally, we show that\n                  <jats:italic>P. aeruginosa<\/jats:italic>\n                  consumes nitrate in lysogeny broth (LB) under microoxic conditions. Furthermore, strains without a functioning quorum sensing regulator LasR, which leads to elevated Anr activity, consume nitrate in LB even in normoxia. There was no growth advantage for\n                  <jats:italic>P. aeruginosa<\/jats:italic>\n                  when nitrate was present at concentrations from 100 \u00b5M to 1600 \u00b5M. However,\n                  <jats:italic>P. aeruginosa<\/jats:italic>\n                  consumption of nitrate in oxic conditions created a requirement for Dnr and Dnr-regulated NorCB likely due to the need to detoxify nitric oxide. These studies suggest that Anr- and Dnr-regulated processes may impact\n                  <jats:italic>P. aeruginosa<\/jats:italic>\n                  physiology in many common culture conditions.\n                <\/jats:p>\n                <jats:sec>\n                  <jats:title>Importance<\/jats:title>\n                  <jats:p>\n                    <jats:italic>Pseudomonas aeruginosa<\/jats:italic>\n                    is an opportunistic pathogen commonly isolated from low-oxygen environments such as the lungs of people with cystic fibrosis. While the importance of\n                    <jats:italic>P. aeruginosa<\/jats:italic>\n                    energy generation by denitrification is clear in anoxic environments, the effects of denitrification in oxic cultures is not clear. Here, we show that nitrate is consumed even in oxic environments and while it does not appear to stimulate growth, it does impact fitness. Further, we report that two regulators that are best known for their roles in anoxic conditions also contribute to\n                    <jats:italic>P. aeruginosa<\/jats:italic>\n                    fitness in commonly- used laboratory media in presence of oxygen.\n                  <\/jats:p>\n                <\/jats:sec>","DOI":"10.1101\/2025.03.31.646406","type":"posted-content","created":{"date-parts":[[2025,4,1]],"date-time":"2025-04-01T00:50:25Z","timestamp":1743468625000},"source":"Crossref","is-referenced-by-count":0,"title":["Role of\n                  <i>Pseudomonas aeruginosa<\/i>\n                  Dnr-regulated denitrification in oxic conditions"],"prefix":"10.64898","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9723-7677","authenticated-orcid":false,"given":"Stacie Stuut","family":"Balsam","sequence":"first","affiliation":[{"name":"Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6939-1351","authenticated-orcid":false,"given":"Dallas L.","family":"Mould","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3056-8356","authenticated-orcid":false,"given":"Fabrice","family":"Jean-Pierre","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-6366-2971","authenticated-orcid":false,"given":"Deborah A.","family":"Hogan","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, USA"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"54368","reference":[{"key":"2026041201351026000_2025.03.31.646406v1.1","doi-asserted-by":"publisher","DOI":"10.1172\/JCI200213870"},{"key":"2026041201351026000_2025.03.31.646406v1.2","doi-asserted-by":"publisher","DOI":"10.1128\/AEM.70.10.6188-6196.2004"},{"key":"2026041201351026000_2025.03.31.646406v1.3","doi-asserted-by":"publisher","DOI":"10.1186\/1471-2180-10-294"},{"key":"2026041201351026000_2025.03.31.646406v1.4","doi-asserted-by":"publisher","DOI":"10.1128\/jb.173.5.1598-1606.1991"},{"key":"2026041201351026000_2025.03.31.646406v1.5","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-2958.1991.tb00793.x"},{"key":"2026041201351026000_2025.03.31.646406v1.6","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-2958.1991.tb00794.x"},{"key":"2026041201351026000_2025.03.31.646406v1.7","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.271.5.2762"},{"key":"2026041201351026000_2025.03.31.646406v1.8","doi-asserted-by":"publisher","DOI":"10.1128\/jb.177.12.3606-3609.1995"},{"key":"2026041201351026000_2025.03.31.646406v1.9","doi-asserted-by":"publisher","DOI":"10.1111\/j.1365-2958.2007.05772.x"},{"key":"2026041201351026000_2025.03.31.646406v1.10","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.1917576117"},{"key":"2026041201351026000_2025.03.31.646406v1.11","doi-asserted-by":"publisher","DOI":"10.1021\/acs.biochem.4c00174"},{"key":"2026041201351026000_2025.03.31.646406v1.12","doi-asserted-by":"publisher","DOI":"10.1099\/mic.0.081158-0"},{"key":"2026041201351026000_2025.03.31.646406v1.13","first-page":"0041621","article-title":"Both Pseudomonas aeruginosa and Candida albicans Accumulate Greater Biomass in Dual-Species Biofilms under Flow","volume":"6","year":"2021","journal-title":"mSphere"},{"key":"2026041201351026000_2025.03.31.646406v1.14","doi-asserted-by":"publisher","DOI":"10.1016\/j.jcf.2008.09.006"},{"key":"2026041201351026000_2025.03.31.646406v1.15","doi-asserted-by":"crossref","unstructured":"O\u2019Connor K , Zhao CY , Mei M , Diggle SP . 2022. Frequency of quorum-sensing mutations in Pseudomonas aeruginosa strains isolated from different environments. Microbiology (Reading) 168.","DOI":"10.1099\/mic.0.001265"},{"key":"2026041201351026000_2025.03.31.646406v1.16","doi-asserted-by":"publisher","DOI":"10.1101\/2023.08.22.554354"},{"key":"2026041201351026000_2025.03.31.646406v1.17","doi-asserted-by":"publisher","DOI":"10.1128\/JB.00182-15"},{"key":"2026041201351026000_2025.03.31.646406v1.18","doi-asserted-by":"publisher","DOI":"10.1016\/0014-5793(95)00885-D"},{"key":"2026041201351026000_2025.03.31.646406v1.19","doi-asserted-by":"publisher","DOI":"10.1046\/j.1365-2958.1997.5431906.x"},{"key":"2026041201351026000_2025.03.31.646406v1.20","doi-asserted-by":"crossref","first-page":"481","DOI":"10.1111\/j.1432-1033.1994.tb19962.x","article-title":"Nitric oxide reductase from Pseudomonas stutzeri. Primary structure and gene organization of a novel bacterial cytochrome bc complex","volume":"219","year":"1994","journal-title":"Eur J Biochem"},{"key":"2026041201351026000_2025.03.31.646406v1.21","doi-asserted-by":"publisher","DOI":"10.1016\/S0168-6445(03)00066-4"},{"key":"2026041201351026000_2025.03.31.646406v1.22","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pcbi.0010055"},{"key":"2026041201351026000_2025.03.31.646406v1.23","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.M702003200"},{"key":"2026041201351026000_2025.03.31.646406v1.24","doi-asserted-by":"publisher","DOI":"10.1099\/mic.0.25936-0"},{"key":"2026041201351026000_2025.03.31.646406v1.25","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0118235"},{"key":"2026041201351026000_2025.03.31.646406v1.26","doi-asserted-by":"publisher","DOI":"10.1111\/j.1462-2920.2010.02252.x"},{"key":"2026041201351026000_2025.03.31.646406v1.27","doi-asserted-by":"crossref","first-page":"e0025021","DOI":"10.1128\/JB.00250-21","article-title":"Impact of Artificial Sputum Medium Formulation on Pseudomonas aeruginosa Secondary Metabolite Production","volume":"203","year":"2021","journal-title":"J Bacteriol"},{"key":"2026041201351026000_2025.03.31.646406v1.28","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.1419677112"},{"key":"2026041201351026000_2025.03.31.646406v1.29","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.2406234121"},{"key":"2026041201351026000_2025.03.31.646406v1.30","doi-asserted-by":"publisher","DOI":"10.1128\/JB.01138-07"},{"key":"2026041201351026000_2025.03.31.646406v1.31","doi-asserted-by":"publisher","DOI":"10.1128\/JB.00162-07"},{"key":"2026041201351026000_2025.03.31.646406v1.32","doi-asserted-by":"publisher","DOI":"10.1164\/ajrccm.158.1.9707096"},{"key":"2026041201351026000_2025.03.31.646406v1.33","doi-asserted-by":"publisher","DOI":"10.1128\/AEM.69.11.6715-6722.2003"},{"key":"2026041201351026000_2025.03.31.646406v1.34","doi-asserted-by":"crossref","first-page":"8557","DOI":"10.1038\/s41598-022-11957-4","article-title":"Nitrate respiration occurs throughout the depth of mucoid and non-mucoid Pseudomonas aeruginosa submerged agar colony biofilms including the oxic zone","volume":"12","year":"2022","journal-title":"Sci Rep"},{"key":"2026041201351026000_2025.03.31.646406v1.35","doi-asserted-by":"publisher","DOI":"10.1016\/S0169-409X(02)00152-7"},{"key":"2026041201351026000_2025.03.31.646406v1.36","doi-asserted-by":"publisher","DOI":"10.1016\/S1534-5807(02)00295-2"},{"key":"2026041201351026000_2025.03.31.646406v1.37","doi-asserted-by":"publisher","DOI":"10.1128\/JB.00975-09"},{"key":"2026041201351026000_2025.03.31.646406v1.38","doi-asserted-by":"publisher","DOI":"10.1099\/mic.0.028027-0"},{"key":"2026041201351026000_2025.03.31.646406v1.39","doi-asserted-by":"publisher","DOI":"10.1002\/prot.22428"},{"key":"2026041201351026000_2025.03.31.646406v1.40","doi-asserted-by":"publisher","DOI":"10.1016\/j.jmb.2008.03.013"},{"key":"2026041201351026000_2025.03.31.646406v1.41","doi-asserted-by":"publisher","DOI":"10.1111\/j.1574-6968.1999.tb13350.x"},{"key":"2026041201351026000_2025.03.31.646406v1.42","doi-asserted-by":"publisher","DOI":"10.1172\/JCI24684"},{"key":"2026041201351026000_2025.03.31.646406v1.43","doi-asserted-by":"publisher","DOI":"10.1016\/j.freeradbiomed.2014.08.011"},{"key":"2026041201351026000_2025.03.31.646406v1.44","doi-asserted-by":"publisher","DOI":"10.1074\/jbc.M409996200"},{"key":"2026041201351026000_2025.03.31.646406v1.45","doi-asserted-by":"crossref","first-page":"22785","DOI":"10.1016\/S0021-9258(18)54420-3","article-title":"Marker exchange of the structural genes for nitric oxide reductase blocks the denitrification pathway of Pseudomonas stutzeri at nitric oxide","volume":"266","year":"1991","journal-title":"J Biol Chem"},{"key":"2026041201351026000_2025.03.31.646406v1.46","doi-asserted-by":"publisher","DOI":"10.1038\/sj.emboj.7601787"},{"key":"2026041201351026000_2025.03.31.646406v1.47","doi-asserted-by":"publisher","DOI":"10.1378\/chest.122.6.2127"},{"key":"2026041201351026000_2025.03.31.646406v1.48","doi-asserted-by":"publisher","DOI":"10.4161\/viru.20328"},{"key":"2026041201351026000_2025.03.31.646406v1.49","doi-asserted-by":"publisher","DOI":"10.1016\/j.niox.2012.02.002"},{"key":"2026041201351026000_2025.03.31.646406v1.50","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.97.16.8841"},{"key":"2026041201351026000_2025.03.31.646406v1.51","doi-asserted-by":"publisher","DOI":"10.1016\/S0952-7915(99)00052-7"},{"key":"2026041201351026000_2025.03.31.646406v1.52","doi-asserted-by":"publisher","DOI":"10.1128\/IAI.00437-16"},{"key":"2026041201351026000_2025.03.31.646406v1.53","doi-asserted-by":"publisher","DOI":"10.1086\/599360"},{"key":"2026041201351026000_2025.03.31.646406v1.54","doi-asserted-by":"publisher","DOI":"10.1016\/j.tim.2008.12.003"},{"key":"2026041201351026000_2025.03.31.646406v1.55","doi-asserted-by":"crossref","unstructured":"Martin LW , Gray AR , Brockway B , Lamont IL . 2023. Pseudomonas aeruginosa is oxygen-deprived during infection in cystic fibrosis lungs, reducing the effectiveness of antibiotics. FEMS Microbiol Lett 370.","DOI":"10.1093\/femsle\/fnad076"},{"key":"2026041201351026000_2025.03.31.646406v1.56","doi-asserted-by":"crossref","unstructured":"Cornforth DM , Diggle FL , Melvin JA , Bomberger JM , Whiteley M . 2020. Quantitative Framework for Model Evaluation in Microbiology Research Using Pseudomonas aeruginosa and Cystic Fibrosis Infection as a Test Case. mBio 11.","DOI":"10.1128\/mBio.03042-19"},{"key":"2026041201351026000_2025.03.31.646406v1.57","doi-asserted-by":"crossref","first-page":"e0315723","DOI":"10.1128\/spectrum.03157-23","article-title":"Pseudomonas aeruginosa transcriptome analysis of metal restriction in ex vivo cystic fibrosis sputum","volume":"12","year":"2024","journal-title":"Microbiol Spectr"},{"key":"2026041201351026000_2025.03.31.646406v1.58","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0147811"},{"key":"2026041201351026000_2025.03.31.646406v1.59","doi-asserted-by":"publisher","DOI":"10.3389\/fmicb.2014.00554"},{"key":"2026041201351026000_2025.03.31.646406v1.60","doi-asserted-by":"publisher","DOI":"10.1046\/j.1365-2958.2003.03904.x"},{"key":"2026041201351026000_2025.03.31.646406v1.61","doi-asserted-by":"publisher","DOI":"10.3389\/fmicb.2011.00103"},{"key":"2026041201351026000_2025.03.31.646406v1.62","doi-asserted-by":"publisher","DOI":"10.1046\/j.1365-2958.1998.00980.x"},{"key":"2026041201351026000_2025.03.31.646406v1.63","doi-asserted-by":"publisher","DOI":"10.1128\/JB.186.14.4596-4604.2004"},{"key":"2026041201351026000_2025.03.31.646406v1.64","doi-asserted-by":"publisher","DOI":"10.1128\/JB.160.3.928-934.1984"},{"key":"2026041201351026000_2025.03.31.646406v1.65","doi-asserted-by":"crossref","unstructured":"Crocker AW , Harty CE , Hammond JH , Willger SD , Salazar P , Botelho NJ , Jacobs NJ , Hogan DA . 2019. Pseudomonas aeruginosa Ethanol Oxidation by AdhA in Low-Oxygen Environments. J Bacteriol 201.","DOI":"10.1128\/JB.00393-19"},{"key":"2026041201351026000_2025.03.31.646406v1.66","doi-asserted-by":"crossref","first-page":"521","DOI":"10.1128\/aem.46.2.521-524.1983","article-title":"Evaluation of Nitrate Reductase Activity in Rhizobium japonicum","volume":"46","year":"1983","journal-title":"Appl Environ Microbiol"},{"key":"2026041201351026000_2025.03.31.646406v1.67","doi-asserted-by":"publisher","DOI":"10.1073\/pnas.0511100103"}],"container-title":[],"original-title":[],"link":[{"URL":"https:\/\/syndication.highwire.org\/content\/doi\/10.1101\/2025.03.31.646406","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,4,12]],"date-time":"2026-04-12T08:35:21Z","timestamp":1775982921000},"score":1,"resource":{"primary":{"URL":"http:\/\/biorxiv.org\/lookup\/doi\/10.1101\/2025.03.31.646406"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2025,3,31]]},"references-count":67,"URL":"https:\/\/doi.org\/10.1101\/2025.03.31.646406","relation":{},"subject":[],"published":{"date-parts":[[2025,3,31]]},"subtype":"preprint"}}