Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

NIH/NIAID On the resistance of Staphylococcus aureus to neutrophil microbicides

ABSTRACT: Staphylococcus aureus strain MW2 was exposed to the following neutrophil microbicides, hydrogen peroxide (H2O2), hypochlorous acid (HOCl) and azurophilic granule proteins. At the indicated time points, bacterial cultures were centrifuged and bacteria were lysed with RLT buffer (Qiagen) using a FastPrep system. Purification of MW2 RNA and subsequent preparation of labeled cDNA target was performed as described in Methods. Labeling of samples, GeneChip hybridization and scanning were performed according to standard Affymetrix protocols. Experiments were performed in triplicate, using three bacterial cultures from separate days for each treatment. These analyses provide an enhanced view of the mechanisms used by CA-MRSA to circumvent destruction by the human innate immune system. 48 samples total: MW2 with the following treatments, untreated, GP (azurophilic granule proteins), H2O2 (hydrogen peroxide) or HOCl (hypochlorous acid) at 4 time points in triplicate

ORGANISM(S): Staphylococcus aureus

SUBMITTER: Kevin Braughton

PROVIDER: E-GEOD-6716 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Publications

Neutrophil microbicides induce a pathogen survival response in community-associated methicillin-resistant Staphylococcus aureus.

Palazzolo-Ballance Amy M AM Reniere Michelle L ML Braughton Kevin R KR Sturdevant Daniel E DE Otto Michael M Kreiswirth Barry N BN Skaar Eric P EP DeLeo Frank R FR

Journal of immunology (Baltimore, Md. : 1950) 20080101 1

In recent years, there has been a dramatic increase in the incidence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) infections. MW2 (pulsed-field type USA400), the prototype CA-MRSA strain, is highly virulent and has enhanced ability to evade killing by neutrophils. Although progress has been made, the molecular basis for enhanced virulence of CA-MRSA remains incompletely defined. To that end, we studied resistance of MW2 to key microbicides of human neutrophils. H ...[more]

PMID: 18097052

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Project description:Oxidative stress due to endogenous hydrogen peroxide production by Lactobacillus species is a well-known issue in the food industry. In this study, the transcriptional response to oxygen of Lactobacillus johnsonii, one of the H2O2-producing strains used in the food industry, was analyzed. It was found that aerobic growth conditions led to a more than two-fold downregulation of 45 genes as compared to anaerobic growth, whereas 6 genes were more than twofold upregulated. Among the upregulated genes were two genes that displayed significant homology to NADH-dependent oxidoreductase (NOX). The postulated transcriptional regulation of the nox promoter by oxygen was studied using a GUS-reporter construct, confirming a 2.1-fold upregulated GUS-expression upon aerobic growth. Exposure to sublethal levels of hydrogen peroxide did not result in significant regulation of the nox promoter. In a previous study of hydrogen peroxide production by L. johnsonii, a NADH flavin reductase (NFR) was identified to be involved in hydrogen peroxide production. An NFR-deficient derivative was strongly impaired in H2O2 production, but regained a partial H2O2 producing capacity upon prolonged oxygen exposure. The nox-promoter appeared to be 3.6-fold upregulated under aerobic conditions in the NFR-deficient background, which may imply a role of this gene in the regained H2O2 production. Indeed, deletion of the nox-gene in the NFR-deletion background, resulted in a strain that no longer produced H2O2, also during prolonged exposure to oxygen. The double-mutant (nfr, nox) displayed strongly impaired aerobic growth and oxygenation induced rapid growth stagnation that is not caused by H2O2. We conclude that H2O2 production in L. johnsonii is primarily dependent on NFR but can also involve an oxygen-inducible NADH oxidase under aerobic conditions. Moreover, our results imply that H2O2 production plays a prominent role in oxygen tolerance of L. johnsonii. loop design of the samples including two shortcuts

Dataset Information

NIH/NIAID On the resistance of Staphylococcus aureus to neutrophil microbicides

Publications

Neutrophil microbicides induce a pathogen survival response in community-associated methicillin-resistant Staphylococcus aureus.

Similar Datasets

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