Unknown

Dataset Information

0

Mutation of the NADH oxidase gene (nox) reveals an overlap of the oxygen- and acid-mediated stress responses in Streptococcus mutans.


ABSTRACT: NADH oxidase (Nox) is a flavin-containing enzyme used by Streptococcus mutans to reduce dissolved oxygen encountered during growth in the oral cavity. In this study, we characterized the role of the NADH oxidase in the oxidative and acid stress responses of S. mutans. A nox-defective mutant strain of S. mutans and its parental strain, the genomic type strain UA159, were exposed to various oxygen concentrations at pH values of 5 and 7 to better understand the adaptive mechanisms used by the organism to withstand environmental pressures. With the loss of nox, the activities of oxygen stress response enzymes such as superoxide dismutase and glutathione oxidoreductase were elevated compared to those in controls, resulting in a greater adaptation to oxygen stress. In contrast, the loss of nox led to a decreased ability to grow in a low-pH environment despite an increased resistance to severe acid challenge. Analysis of the membrane fatty acid composition revealed that for both the nox mutant and UA159 parent strain, growth in an oxygen-rich environment resulted in high proportions of unsaturated membrane fatty acids, independent of external pH. The data indicate that S. mutans membrane fatty acid composition is responsive to oxidative stress, as well as changes in environmental pH, as previously reported (E. M. Fozo and R. G. Quivey, Jr., Appl. Environ. Microbiol. 70:929-936, 2004). The heightened ability of the nox strain to survive acidic and oxidative environmental stress suggests a multifaceted response system that is partially dependent on oxygen metabolites.

SUBMITTER: Derr AM 

PROVIDER: S-EPMC3273017 | biostudies-literature | 2012 Feb

REPOSITORIES: biostudies-literature

altmetric image

Publications

Mutation of the NADH oxidase gene (nox) reveals an overlap of the oxygen- and acid-mediated stress responses in Streptococcus mutans.

Derr Adam M AM   Faustoferri Roberta C RC   Betzenhauser Matthew J MJ   Gonzalez Kaisha K   Marquis Robert E RE   Quivey Robert G RG  

Applied and environmental microbiology 20111216 4


NADH oxidase (Nox) is a flavin-containing enzyme used by Streptococcus mutans to reduce dissolved oxygen encountered during growth in the oral cavity. In this study, we characterized the role of the NADH oxidase in the oxidative and acid stress responses of S. mutans. A nox-defective mutant strain of S. mutans and its parental strain, the genomic type strain UA159, were exposed to various oxygen concentrations at pH values of 5 and 7 to better understand the adaptive mechanisms used by the organ  ...[more]

Similar Datasets

| S-EPMC4054193 | biostudies-literature
2012-10-04 | GSE38803 | GEO
2014-04-01 | GSE56118 | GEO
| S-EPMC3995211 | biostudies-literature
2012-10-04 | E-GEOD-38803 | biostudies-arrayexpress
2014-04-01 | E-GEOD-56118 | biostudies-arrayexpress
| S-EPMC4626894 | biostudies-literature
| S-EPMC4780693 | biostudies-literature
| S-EPMC94295 | biostudies-literature
| S-EPMC3302633 | biostudies-literature