Functional and Genomic Evidence of L-Arginine-Dependent Bacterial Nitric Oxide Synthase Activity in <i>Paenibacillus nitricinens</i> sp. nov.
Although nitric oxide (NO) production in bacteria has traditionally been associated with denitrification or stress responses in model or symbiotic organisms, functionally validated L-arginine-dependent nitric oxide synthase (bNOS) activity has not been documented in free-living, non-denitrifying soi...
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2025-06-01
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| author | Diego Saavedra-Tralma Alexis Gaete Carolina Merino-Guzmán Maribel Parada-Ibáñez Francisco Nájera-de Ferrari Ignacio Jofré-Fernández |
| author_facet | Diego Saavedra-Tralma Alexis Gaete Carolina Merino-Guzmán Maribel Parada-Ibáñez Francisco Nájera-de Ferrari Ignacio Jofré-Fernández |
| author_sort | Diego Saavedra-Tralma |
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| description | Although nitric oxide (NO) production in bacteria has traditionally been associated with denitrification or stress responses in model or symbiotic organisms, functionally validated L-arginine-dependent nitric oxide synthase (bNOS) activity has not been documented in free-living, non-denitrifying soil bacteria. This paper reports <i>Paenibacillus nitricinens</i> sp. nov., a bacterium isolated from rainforest soil capable of synthesizing NO via a bNOS under aerobic conditions. A <i>bnos</i>-specific PCR confirmed gene presence, while whole-genome sequencing (6.7 Mb, 43.79% GC) revealed two nitrogen metabolism pathways, including a <i>bnos</i>-like gene. dDDH (<70%) and ANI (<95%) values with related <i>Paenibacillus</i> strains support the delineation of this isolate as a distinct species. Extracellular and intracellular NO measurements under aerobic conditions showed a dose-dependent response, with detectable production at 0.1 µM L-arginine and saturation at 100 µM. The addition of L-NAME reduced NO formation, confirming enzymatic mediation. The genomic identification of a <i>bnos</i>-like gene strongly supports the presence of a functional pathway. The absence of canonical nitric oxide reductase (<i>Nor</i>) genes or other typical denitrification-related enzymes reinforces that NO production arises from an alternative, intracellular enzymatic mechanism rather than classical denitrification. Consequently, <i>P. nitricinens</i> expands the known repertoire of microbial NO synthesis and suggests a previously overlooked source of NO flux in well-aerated soils. |
| format | Article |
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| language | English |
| publishDate | 2025-06-01 |
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| spelling | doaj-art-bb90f7ac3b214e239cf0b1a38549b6562025-08-20T02:24:22ZengMDPI AGBiology2079-77372025-06-0114673310.3390/biology14060733Functional and Genomic Evidence of L-Arginine-Dependent Bacterial Nitric Oxide Synthase Activity in <i>Paenibacillus nitricinens</i> sp. nov.Diego Saavedra-Tralma0Alexis Gaete1Carolina Merino-Guzmán2Maribel Parada-Ibáñez3Francisco Nájera-de Ferrari4Ignacio Jofré-Fernández5Scientific and Technological Bioresource Nucleus (BIOREN), Universidad de La Frontera, Avenida Francisco Salazar 01145, P.O. Box 54-D, Temuco 4811230, ChileMillennium Institute Center for Genome Regulation (CGR), Valenzuela Puelma 10207, La Reina, Santiago 7860006, ChileLaboratory of Geomicrobiology, Department of Chemical Sciences and Natural Resources, Universidad de La Frontera, Avenida Francisco Salazar 01145, P.O. Box 54-D, Temuco 4811230, ChileLaboratory of Rhizobiology and Microbiology, Facultad de Ciencias Agropecuarias y Medioambiente, Universidad de La Frontera, Avenida Francisco Salazar 01145, P.O. Box 54-D, Temuco 4811230, ChileScientific and Technological Bioresource Nucleus (BIOREN), Universidad de La Frontera, Avenida Francisco Salazar 01145, P.O. Box 54-D, Temuco 4811230, ChileScientific and Technological Bioresource Nucleus (BIOREN), Universidad de La Frontera, Avenida Francisco Salazar 01145, P.O. Box 54-D, Temuco 4811230, ChileAlthough nitric oxide (NO) production in bacteria has traditionally been associated with denitrification or stress responses in model or symbiotic organisms, functionally validated L-arginine-dependent nitric oxide synthase (bNOS) activity has not been documented in free-living, non-denitrifying soil bacteria. This paper reports <i>Paenibacillus nitricinens</i> sp. nov., a bacterium isolated from rainforest soil capable of synthesizing NO via a bNOS under aerobic conditions. A <i>bnos</i>-specific PCR confirmed gene presence, while whole-genome sequencing (6.7 Mb, 43.79% GC) revealed two nitrogen metabolism pathways, including a <i>bnos</i>-like gene. dDDH (<70%) and ANI (<95%) values with related <i>Paenibacillus</i> strains support the delineation of this isolate as a distinct species. Extracellular and intracellular NO measurements under aerobic conditions showed a dose-dependent response, with detectable production at 0.1 µM L-arginine and saturation at 100 µM. The addition of L-NAME reduced NO formation, confirming enzymatic mediation. The genomic identification of a <i>bnos</i>-like gene strongly supports the presence of a functional pathway. The absence of canonical nitric oxide reductase (<i>Nor</i>) genes or other typical denitrification-related enzymes reinforces that NO production arises from an alternative, intracellular enzymatic mechanism rather than classical denitrification. Consequently, <i>P. nitricinens</i> expands the known repertoire of microbial NO synthesis and suggests a previously overlooked source of NO flux in well-aerated soils.https://www.mdpi.com/2079-7737/14/6/733aerobic NO productionbacterial nitric oxide synthaseL-arginine metabolismnitric oxide |
| spellingShingle | Diego Saavedra-Tralma Alexis Gaete Carolina Merino-Guzmán Maribel Parada-Ibáñez Francisco Nájera-de Ferrari Ignacio Jofré-Fernández Functional and Genomic Evidence of L-Arginine-Dependent Bacterial Nitric Oxide Synthase Activity in <i>Paenibacillus nitricinens</i> sp. nov. Biology aerobic NO production bacterial nitric oxide synthase L-arginine metabolism nitric oxide |
| title | Functional and Genomic Evidence of L-Arginine-Dependent Bacterial Nitric Oxide Synthase Activity in <i>Paenibacillus nitricinens</i> sp. nov. |
| title_full | Functional and Genomic Evidence of L-Arginine-Dependent Bacterial Nitric Oxide Synthase Activity in <i>Paenibacillus nitricinens</i> sp. nov. |
| title_fullStr | Functional and Genomic Evidence of L-Arginine-Dependent Bacterial Nitric Oxide Synthase Activity in <i>Paenibacillus nitricinens</i> sp. nov. |
| title_full_unstemmed | Functional and Genomic Evidence of L-Arginine-Dependent Bacterial Nitric Oxide Synthase Activity in <i>Paenibacillus nitricinens</i> sp. nov. |
| title_short | Functional and Genomic Evidence of L-Arginine-Dependent Bacterial Nitric Oxide Synthase Activity in <i>Paenibacillus nitricinens</i> sp. nov. |
| title_sort | functional and genomic evidence of l arginine dependent bacterial nitric oxide synthase activity in i paenibacillus nitricinens i sp nov |
| topic | aerobic NO production bacterial nitric oxide synthase L-arginine metabolism nitric oxide |
| url | https://www.mdpi.com/2079-7737/14/6/733 |
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