Evidence for Nitric Oxide Synthase Activity in Staphylococcus xylosus Mediating Nitrosoheme Formation (original) (raw)
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International Journal of Food Microbiology, 2007
Quantitative determination of catalase, nitrate reductase, nitrite reductase and nitric oxide synthase activities (NOS) was performed on 11 different bacterial strains, mainly staphylococci, isolated from fermented sausages, bacon brine or cured meat products. All except one strain possessed catalase activity in the range from 1.0 to 6.1 μmol min − 1 ml − 1 . Ten out of 11 bacteria strains showed nitrate reductase activity in the range between 50 and 796 nmol min − 1 ml − 1 and nine showed nitrite reductase activity in the range between 6 and 42 nmol min − 1 ml − 1 . No evidence of NOS activity of the selected strains was detected. In a colour formation assay containing myoglobin all strains affected nitrosylmyoglobin (MbFe II NO) formation in assays containing nitrite, whereas only strains having nitrate reductase activity generated MbFe II NO in assays containing nitrate as the sole nitrosylating agent. The quantitative nitrate and nitrite reductase activity did not fully explain or correlate well with the observed rate of formation of MbFe II NO, which seemed to be more affected by the growth rate of the different strains. The mechanism of the reduction of nitrite into NO of strains not having nitrite reductase activity remains to be fully elucidated, but could be due to a dual-mode action of nitrate reductase capable of acting on nitrate.
Molecular Characterization of the Nitrite-Reducing System of Staphylococcus carnosus
Journal of Bacteriology, 1999
Characterization of a nitrite reductase-negativeStaphylococcus carnosus Tn917 mutant led to the identification of the nir operon, which encodes NirBD, the dissimilatory NADH-dependent nitrite reductase; SirA, the putative oxidase and chelatase, and SirB, the uroporphyrinogen III methylase, both of which are necessary for biosynthesis of the siroheme prosthetic group; and NirR, which revealed no convincing similarity to proteins with known functions. We suggest that NirR is essential fornir promoter activity. In the absence of NirR, a weak promoter upstream of sirA seems to drive transcription ofsirA, nirB, nirD, andsirB in the stationary-growth phase. In primer extension experiments one predominant and several weaker transcription start sites were identified in the nir promoter region. Northern blot analyses indicated that anaerobiosis and nitrite are induction factors of the nir operon: cells grown aerobically with nitrite revealed small amounts of full-length transcript whereas ce...
Catalytic properties of nitric oxide synthase chimeras
Nitric Oxide, 2014
Free radical nitric oxide (NO) is an important signaling molecule and inflammatory modulator in the mammalian system. Some microbial pathogens may subvert host NO-signaling through NO-sensing and NO-regulated expression of bacterial NO-metabolism proteins. Moraxella catarrhalis, an opportunistic human pathogen which forms biofilms in vivo [1], expresses NsrR-regulated and biofilm-induced nitrite reductase (AniA) and NO reductase (NorB) [2-4]. NO was commonly known as an intermediate product in bacterial denitrification. However, based on the highly diffusible and reactive nature of NO, we hypothesized that M. catarrhalis-generated NO may be involved in pathogenesis. AniA-mediated nitrite reduction was able to stimulate host cell secretion of proinflammatory cytokines (TNF-α and IL-1α) and induces closely contacted host cells undergoing programmed death in vitro [5]. In this study we monitored nitrite reduction and NO-production by M. catarrhalis O35E wildtype and its NO-metabolism deficient mutant strains in bacterial human host cell co-cultures. We also monitored host cell growth using a live-cell imaging technology to assess overall effects of bacterial NO-metabolism. In a medium containing pathophysiological levels of nitrite, a higher level of NO was detected in co-cultures with wild-type than with aniA mutant cells during an early period of co-culturing, and nitrite was predominantly reduced by biofilm-induced M. catarrhalis AniA during a later period of co-culturing. Higher levels of NO-produced by O35E wild-type or O35E norB mutant cells, or increased NOmetabolism by O35E nsrR mutant cells cause a transition of bacterial-host cell interaction from commensal-like to pathogenic.
Journal of Bacteriology, 2002
In Staphylococcus carnosus, the nreABC (for nitrogen regulation) genes were identified and shown to link the nitrate reductase operon (narGHJI) and the putative nitrate transporter gene narT. An nreABC deletion mutant, m1, was dramatically affected in nitrate and nitrite reduction and growth. Transcription of narT, narGHJI, and the nitrite reductase (nir) operon was severely reduced even when cells were cultivated anaerobically without nitrate or nitrite. nreABC transcripts were detected when cells were grown aerobically or anaerobically with or without nitrate or nitrite. NreA is a GAF domain-containing protein of unknown function. In vivo and in vitro studies showed that NreC is phosphorylated by NreB and that phospho-NreC specifically binds to a GC-rich palindromic sequence to enhance transcription initiation. This binding motif was found at the narGHJI, nir, and narT promoters but not at the moeB promoter. NreB is a cytosolic protein with four N-terminal cysteine residues. The s...
Proteome Response of Staphylococcus xylosus DSM 20266T to Anaerobiosis and Nitrite Exposure
Frontiers in Microbiology, 2018
Staphylococcus xylosus Proteome in NO 2-Response for glycolysis or fueling alternative pathways to TCA cycle. In conclusion, metabolic pathways underlying the ability of S. xylosus to adapt itself to oxygen starvation were revealed; the addition of nitrite allowed S. xylosus to take advantage of nitrite to this condition, restoring some metabolic pathway underlying aerobic behavior of the strain.
Proceedings of the National Academy of Sciences, 2009
The role of nitric oxide (NO) in the host response to infection and in cellular signaling is well established. Enzymatic synthesis of NO is catalyzed by the nitric oxide synthases (NOSs), which convert Arg into NO and citrulline using co-substrates O 2 and NADPH. Mammalian NOS contains a flavin reductase domain (FAD and FMN) and a catalytic heme oxygenase domain (P450-type heme and tetrahydrobiopterin). Bacterial NOSs, while much less studied, were previously identified as only containing the heme oxygenase domain of the more complex mammalian NOSs. We report here on the characterization of a NOS from Sorangium cellulosum (both full-length, scNOS, and oxygenase domain, scNOSox). scNOS contains a catalytic, oxygenase domain similar to those found in the mammalian NOS and in other bacteria. Unlike the other bacterial NOSs reported to date, however, this protein contains a fused reductase domain. The scNOS reductase domain is unique for the entire NOS family because it utilizes a 2Fe2S...
Nitrosative stress in Escherichia coli : reduction of nitric oxide
Biochemical Society Transactions, 2011
The ability of enteric bacteria to protect themselves against reactive nitrogen species generated by their own metabolism, or as part of the innate immune response, is critical to their survival. One important defence mechanism is their ability to reduce NO (nitric oxide) to harmless products. The highest rates of NO reduction by Escherichia coli K-12 were detected after anaerobic growth in the presence of nitrate. Four proteins have been implicated as catalysts of NO reduction: the cytoplasmic sirohaem-containing nitrite reductase, NirB; the periplasmic cytochrome c nitrite reductase, NrfA; the flavorubredoxin NorV and its associated oxidoreductase, NorW; and the flavohaemoglobin, Hmp. Single mutants defective in any one of these proteins and even the mutant defective in all four proteins reduced NO at the same rate as the parent. Clearly, therefore, there are mechanisms of NO reduction by enteric bacteria that remain to be characterized. Far from being minor pathways, the currentl...
Antioxidant Functions of Nitric Oxide Synthase in a Methicillin SensitiveStaphylococcus aureus
International Journal of Microbiology, 2013
Nitric oxide and its derivative peroxynitrites are generated by host defense system to control bacterial infection. However certain Gram positive bacteria includingStaphylococcus aureuspossess a gene encoding nitric oxide synthase (SaNOS) in their chromosome. In this study it was determined that under normal growth conditions, expression ofSaNOSwas highest during early exponential phase of the bacterial growth. In oxidative stress studies, deletion ofSaNOSled to increased susceptibility of the mutant cells compared to wild-typeS. aureus. While inhibition ofSaNOSactivity by the addition of L-NAME increased sensitivity of the wild-typeS. aureusto oxidative stress, the addition of a nitric oxide donor, sodium nitroprusside, restored oxidative stress tolerance of theSaNOSmutant. TheSaNOSmutant also showed reduced survival after phagocytosis by PMN cells with respect to wild-typeS. aureus.