Characterization of the Streptococcus pneumoniae NADH oxidase that is required for infection

Yu, Jun; Bryant, Alexander P.; Marra, Andrea; Lonetto, Michael A.; Ingraham, Karen; Chalker, Alison F.; Holmes, David; Holden, David W.; Rosenberg, Martin; McDevitt, Damien

doi:10.1099/00221287-147-2-431

Cited by 59 publications

(45 citation statements)

References 36 publications

(20 reference statements)

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“…In pathogenic streptococci that encounter oxygen upon host colonization, NADH oxidases contribute to oxygen tolerance by decreasing the intracellular NADH/NAD ratio and/or by direct elimination of oxygen (2,10,14,37,38). In L. lactis, which is particularly exposed to oxygen when it is used for milk fermentation in the dairy industry, the role of NADH oxidases in oxygen tolerance has not been investigated.…”

Section: Discussionmentioning

confidence: 99%

“…Their inactivation in several streptococci strongly reduces the aerobic growth. Inactivation of nox2 in Streptococcus pneumoniae and Streptococcus agalactiae reduces growth in aerated media by 80% (37,38). The growth defect of the S. agalactiae mutant has been attributed to a defect in fatty acid production resulting from nonproduction of the fatty acid precursor acetyl-coenzyme A (CoA) due to strictly homolactic fermentation (37).…”

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confidence: 99%

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Identification of a Conserved Sequence in Flavoproteins Essential for the Correct Conformation and Activity of the NADH Oxidase NoxE of Lactococcus lactis

2011

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Water-forming NADH oxidases (encoded by noxE, nox2, or nox) are flavoproteins generally implicated in the aerobic survival of microaerophilic bacteria, such as lactic acid bacteria. However, some natural Lactococcus lactis strains produce an inactive NoxE. We examined the role of NoxE in the oxygen tolerance of L. lactis in the rich synthetic medium GM17. Inactivation of noxE suppressed 95% of NADH oxidase activity but only slightly affected aerobic growth, oxidative stress resistance, and NAD regeneration. However, noxE inactivation strongly impaired oxygen consumption and mixed-acid fermentation. We found that the A303T mutation is responsible for the loss of activity of a naturally occurring variant of NoxE. Replacement of A303 with T or G or of G307 with S or A by site-directed mutagenesis led to NoxE aggregation and the total loss of activity. We demonstrated that L299 is involved in NoxE activity, probably contributing to positioning flavin adenine dinucleotide (FAD) in the active site. These residues are part of the strongly conserved sequence LA(T)XXA XXXG included in an alpha helix that is present in other flavoprotein disulfide reductase (FDR) family flavoproteins that display very similar three-dimensional structures.Water-forming NADH oxidases (Nox, NoxE, or Nox2) are flavoproteins involved in the aerobic growth and survival of lactic acid bacteria (LAB) under fermentation conditions (7). Their inactivation in several streptococci strongly reduces the aerobic growth. Inactivation of nox2 in Streptococcus pneumoniae and Streptococcus agalactiae reduces growth in aerated media by 80% (37, 38). The growth defect of the S. agalactiae mutant has been attributed to a defect in fatty acid production resulting from nonproduction of the fatty acid precursor acetyl-coenzyme A (CoA) due to strictly homolactic fermentation (37). Nox2 inactivation in Streptococcus mutans also leads to strict homolactic fermentation on glucose; however, it does not affect growth on glucose but greatly reduces growth on mannitol (11). In Streptococcus pyogenes, Nox2 inactivation completely abolishes aerobic growth under carbon limitation conditions and increases sensitivity to the superoxide-generating agent paraquat (methyl viologen). This growth defect has been attributed to hydrogen peroxide (H 2 O 2 ) accumulation (10). NoxE is the principal enzyme displaying NADH oxidase (NOX) activity in Lactococcus lactis (95% of the NADH oxidase activity of L. lactis TIL46), a LAB widely used in industrial milk fermentations and generally considered a model LAB. However, NoxE inactivation in L. lactis reduces the growth rate in milk by only 20%, although it strongly impairs oxygen consumption (34). Moreover, we isolated two natural L. lactis strains without detectable NADH oxidase activity from matured cheese (34), suggesting that NoxE is not important for L. lactis survival in dairy media. In one natural NADH oxidase-negative strain, the noxE gene was complete but the enzyme appeared to be inactive. Several water-forming NADH oxidases from...

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Identification of a Conserved Sequence in Flavoproteins Essential for the Correct Conformation and Activity of the NADH Oxidase NoxE of Lactococcus lactis

2011

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“…However, GlpO is not the only pneumococcal enzyme capable of generating H 2 O 2 . The others are SpxB, which has been implicated in pneumococcal meningitis (albeit using a rat intrathecal challenge model that bypasses the BBB) (40), and the NADH oxidase (Nox), shown to be important in respiratory tract and otitis media infection models (41). It is unlikely that SpxB plays the major role in H 2 O 2 -mediated damage in pneumococcal meningitis.…”

Section: Figurementioning

confidence: 99%

Identification of a novel pneumococcal vaccine antigen preferentially expressed during meningitis in mice

et al. 2012

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Streptococcus pneumoniae is the most common cause of severe bacterial meningitis in children, the elderly, and immunocompromised individuals. To identify virulence factors preferentially expressed during meningitis, we conducted niche-specific genome-wide in vivo transcriptomic analysis after intranasal infection of mice with serotype 4 or 6A pneumococci. The expression of 34 bacterial genes was substantially altered in brain tissue of mice infected with either of the 2 strains. Ten upregulated genes were common to both strains, 7 of which were evaluated for their role in the development of meningitis. One previously uncharacterized protein, α-glycerophosphate oxidase (GlpO), was cytotoxic for human brain microvascular endothelial cells (HBMECs) via generation of H 2 O 2 . A glpO deletion mutant was defective in adherence to HBMECs in vitro as well as in progression from the blood to the brain in vivo. Mutant bacteria also induced markedly reduced meningeal inflammation and brain pathology compared with wild type, despite similar levels of bacteremia. Immunization of mice with GlpO protected against invasive pneumococcal disease and provided additive protection when formulated with pneumolysin toxoid. Our results provide the basis of a strategy that can be adapted to identify genes that contribute to the development of meningitis caused by other pathogens.

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“…If not fully reduced by Nox, environmental oxygen can form toxic superoxide and H 2 O 2 . Strains of GBS and pneumococcus lacking Nox were unable to grow under vigorous agitation conditions and showed attenuated virulence in animal models (514,515). An E. faecium Tn917 transposon insertion mutant of nox showed a 98% reduction of NADH oxidase activity (516).…”

Section: Oxidative Stress and Virulencementioning

confidence: 99%

Stress Physiology of Lactic Acid Bacteria

Papadimitriou

Alegría

Bron

et al. 2016

Microbiol Mol Biol Rev

508

404

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SUMMARYLactic acid bacteria (LAB) are important starter, commensal, or pathogenic microorganisms. The stress physiology of LAB has been studied in depth for over 2 decades, fueled mostly by the technological implications of LAB robustness in the food industry. Survival of probiotic LAB in the host and the potential relatedness of LAB virulence to their stress resilience have intensified interest in the field. Thus, a wealth of information concerning stress responses exists today for strains as diverse as starter (e.g.,Lactococcus lactis), probiotic (e.g., severalLactobacillusspp.), and pathogenic (e.g.,EnterococcusandStreptococcusspp.) LAB. Here we present the state of the art for LAB stress behavior. We describe the multitude of stresses that LAB are confronted with, and we present the experimental context used to study the stress responses of LAB, focusing on adaptation, habituation, and cross-protection as well as on self-induced multistress resistance in stationary phase, biofilms, and dormancy. We also consider stress responses at the population and single-cell levels. Subsequently, we concentrate on the stress defense mechanisms that have been reported to date, grouping them according to their direct participation in preserving cell energy, defending macromolecules, and protecting the cell envelope. Stress-induced responses of probiotic LAB and commensal/pathogenic LAB are highlighted separately due to the complexity of the peculiar multistress conditions to which these bacteria are subjected in their hosts. Induction of prophages under environmental stresses is then discussed. Finally, we present systems-based strategies to characterize the “stressome” of LAB and to engineer new food-related and probiotic LAB with improved stress tolerance.

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Characterization of the Streptococcus pneumoniae NADH oxidase that is required for infection

Cited by 59 publications

References 36 publications

Identification of a Conserved Sequence in Flavoproteins Essential for the Correct Conformation and Activity of the NADH Oxidase NoxE of Lactococcus lactis

Identification of a Conserved Sequence in Flavoproteins Essential for the Correct Conformation and Activity of the NADH Oxidase NoxE of Lactococcus lactis

Identification of a novel pneumococcal vaccine antigen preferentially expressed during meningitis in mice

Stress Physiology of Lactic Acid Bacteria

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