{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,20]],"date-time":"2025-12-20T06:31:44Z","timestamp":1766212304164,"version":"3.48.0"},"reference-count":47,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2025,12,18]],"date-time":"2025-12-18T00:00:00Z","timestamp":1766016000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Microorganisms"],"abstract":"<jats:p>Brucella are intracellular pathogens that use flexible respiratory strategies to adapt to oxygen-limited conditions. The nor operon encodes components of nitric oxide reductase (Nor), which are involved in denitrification and nitric oxide (NO) detoxification. In this study, the role of the norD gene in nitrate-dependent respiration, resistance to nitrosative stress, and intracellular persistence in B. abortus was evaluated. A non-polar \u0394norD mutant was generated in strain 2308W and its survival and growth under aerobic and anaerobic conditions, with and without nitrate, as well as its tolerance to NO donors, were analyzed. In addition, its behavior was evaluated in activated and non-activated murine RAW264.7 and human THP-1 macrophages and in a murine infection model. The deletion of norD did not affect viability or growth under any of the conditions tested, nor did it alter resistance to NO in vitro or within activated macrophages. Furthermore, the mutant showed virulence comparable to the wild-type strain in BALB\/c mice. These results contrast with those described for other Brucella species, suggesting that norD is dispensable in B. abortus 2308W virulence and that in the Brucella genus, there are species-specific differences in the role of the nor operon during infection.<\/jats:p>","DOI":"10.3390\/microorganisms13122875","type":"journal-article","created":{"date-parts":[[2025,12,18]],"date-time":"2025-12-18T09:15:21Z","timestamp":1766049321000},"page":"2875","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Disruption of the Nitric Oxide Reductase Operon via norD Deletion Does Not Affect Brucella abortus 2308W Virulence"],"prefix":"10.3390","volume":"13","author":[{"ORCID":"https:\/\/orcid.org\/0009-0000-4111-5603","authenticated-orcid":false,"given":"Faisal","family":"Rasheed","sequence":"first","affiliation":[{"name":"Department of Zoology, Faculty of Biological Sciences, Quaid-i-Azam University Islamabad, Islamabad 44000, Pakistan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7865-8994","authenticated-orcid":false,"given":"Amaia","family":"Z\u00fa\u00f1iga-Ripa","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Parasitology, Instituto de Investigaci\u00f3n Sanitaria de Navarra (IdiSNA), University of Navarra, 31008 Pamplona, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Miriam","family":"Salvador-Besc\u00f3s","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Parasitology, Instituto de Investigaci\u00f3n Sanitaria de Navarra (IdiSNA), University of Navarra, 31008 Pamplona, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Hamid","family":"Irshad","sequence":"additional","affiliation":[{"name":"National Reference Laboratory for Poultry Diseases, Animal Sciences Institute, National Agricultural Research Centre, Islamabad 44000, Pakistan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0009-0007-3572-2715","authenticated-orcid":false,"given":"Raquel","family":"Pe\u00f1a-Villafruela","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Parasitology, Instituto de Investigaci\u00f3n Sanitaria de Navarra (IdiSNA), University of Navarra, 31008 Pamplona, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Pilar M.","family":"Mu\u00f1oz","sequence":"additional","affiliation":[{"name":"Departamento de Ciencia Animal, Centro de Investigaci\u00f3n y Tecnolog\u00eda Agroalimentaria de Arag\u00f3n (CITA), 50013 Zaragoza, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mar\u00eda Jes\u00fas","family":"de Miguel","sequence":"additional","affiliation":[{"name":"Departamento de Ciencia Animal, Centro de Investigaci\u00f3n y Tecnolog\u00eda Agroalimentaria de Arag\u00f3n (CITA), 50013 Zaragoza, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Qurban","family":"Ali","sequence":"additional","affiliation":[{"name":"National Veterinary Laboratories, Park Road, Islamabad 45710, Pakistan"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0046-3577","authenticated-orcid":false,"given":"Raquel","family":"Conde-\u00c1lvarez","sequence":"additional","affiliation":[{"name":"Department of Microbiology and Parasitology, Instituto de Investigaci\u00f3n Sanitaria de Navarra (IdiSNA), University of Navarra, 31008 Pamplona, Spain"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Saeed-ul-Hassan","family":"Khan","sequence":"additional","affiliation":[{"name":"Department of Zoology, Faculty of Biological Sciences, Quaid-i-Azam University Islamabad, Islamabad 44000, Pakistan"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"1968","published-online":{"date-parts":[[2025,12,18]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"91","DOI":"10.1016\/S1473-3099(06)70382-6","article-title":"V The New Global Map of Human Brucellosis","volume":"6","author":"Pappas","year":"2006","journal-title":"Lancet Infect. 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