Isolation and Characterization of a
            <i>sigB</i>
            Deletion Mutant of
            <i>Staphylococcus aureus</i>

Nicholas, Richard O.; Li, Tong; McDevitt, Damien; Marra, Andrea; Sucoloski, Scott; DeMarsh, Peter; Gentry, Daniel R.

doi:10.1128/iai.67.7.3667-3669.1999

Cited by 90 publications

(28 citation statements)

References 22 publications

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“…Upregulation of sigB was described as downregulating protease production but additionally promoting expression of adherence factors that aid in initial biofilm formation (4,23). Staphylococcal capsules are important in the pathogenesis of S. aureus infections.…”

Section: Resultsmentioning

confidence: 99%

Formation of Staphylococcus aureus Biofilm in the Presence of Sublethal Concentrations of Disinfectants Studied via a Transcriptomic Analysis Using Transcriptome Sequencing (RNA-seq)

Slaný

Oppelt

Cincarova

2017

Appl Environ Microbiol

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is a common biofilm-forming pathogen. Low doses of disinfectants have previously been reported to promote biofilm formation and to increase virulence. The aim of this study was to use transcriptome sequencing (RNA-seq) analysis to investigate global transcriptional changes in in response to sublethal concentrations of the commonly used food industry disinfectants ethanol (EtOH) and chloramine T (ChT) and their combination (EtOH_ChT) in order to better understand the effects of these agents on biofilm formation. Treatment with EtOH and EtOH_ChT resulted in more significantly altered expression profiles than treatment with ChT. Our results revealed that EtOH and EtOH_ChT treatments enhanced the expression of genes responsible for regulation of gene expression (), cell surface factors (), adhesins (), and capsular polysaccharides (), resulting in more intact biofilm. In addition, in this study we were able to identify the pathways involved in the adaptation of to the stress of ChT treatment. Further, EtOH suppressed the effect of ChT on gene expression when these agents were used together at sublethal concentrations. These data show that in the presence of sublethal concentrations of tested disinfectants, cells trigger protective mechanisms and try to cope with them. So far, the effect of disinfectants is not satisfactorily explained. The presented data will allow a better understanding of the mode of disinfectant action with regard to biofilm formation and the ability of bacteria to survive the treatment. Such an understanding could contribute to the effort to eliminate possible sources of bacteria, making disinfectant application as efficient as possible. Biofilm formation plays significant role in the spread and pathogenesis of bacterial species.

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Section: Resultsmentioning

confidence: 99%

Formation of Staphylococcus aureus Biofilm in the Presence of Sublethal Concentrations of Disinfectants Studied via a Transcriptomic Analysis Using Transcriptome Sequencing (RNA-seq)

Slaný

Oppelt

Cincarova

2017

Appl Environ Microbiol

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“…As the promoter region between Newman and RN6390 is identical, the downregulation of hla in strain Newman can probably be explained by differences in trans ‐acting mechanisms. Recently, it was shown that SarA upregulates the alternative σ‐factor, sig B (Chan et al ., 1998), which in turn inhibits hla transcription (Cheung et al ., 1999; Nicholas et al ., 1999;Giachino et al ., 2001). Strain Newman contains an intact sig B operon, which probably accounts for the downregulation of hla in vitro (Giachino et al ., 2001).…”

Section: Discussionmentioning

confidence: 99%

“…In contrast, deletion of the second hla repressor, sar H1, did not result in enhanced hla transcription in an agr ‐negative background (Tegmark et al ., 2000). Furthermore, it has been shown that mutation in sig B (Cheung et al ., 1999; Nicholas et al ., 1999) and in the activator of sig B, rsb U (Giachino et al ., 2001), leads to increased hla transcription.…”

Section: Introductionmentioning

confidence: 99%

Impact of the regulatory loci agr, sarA and sae of Staphylococcus aureus on the induction of α‐toxin during device‐related infection resolved by direct quantitative transcript analysis

Goerke

Flückiger

Steinhuber

et al. 2001

Molecular Microbiology

150

151

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SummaryThe cytotoxic a-toxin (encoded by hla ) of Staphylococcus aureus is regulated by three loci, agr, sarA and sae, in vitro. Here, we assess the regulation of hla in a guinea pig model of device-related infection by quantifying RNAIII (the effector molecule of agr ) and hla directly in exudates accumulating in infected devices without subculturing of the bacteria. LightCycler reverse transcription -polymerase chain reaction (RT-PCR) was used to quantify the transcripts. Strains RN6390 and Newman expressed considerably smaller amounts of RNAIII in the guinea pig than during in vitro growth. The residual RNAIII expression decreased during the course of infection and was negatively correlated with bacterial densities. As with RNAIII, the highest hla expression was detected in both strains early in infection. Even in strain Newman, a weak hla producer in vitro, a pronounced expression of hla was observed during infection. Likewise, four S. aureus isolates from cystic fibrosis (CF) patients expressed hla despite an inactive agr during devicerelated infection as in the CF lung. Mutation of agr and sarA in strain Newman and RN6390 had no consequence for hla expression in vivo. In contrast, the mutation in sae resulted in severe downregulation of hla in vitro as well as in vivo. In conclusion, S. aureus seems to be provided with regulatory circuits different from those characterized in vitro to ensure a-toxin synthesis during infections.

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“…Contrary to sarA and agr, sigB has not been found to play major roles in acute models of infections (106).…”

Section: The Role Of Global Regulators In Virulencementioning

confidence: 97%

Global regulation of virulence determinants in Staphylococcus Aureus by the SarA protein family

Ambrose¹

2002

Front Biosci

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In S. aureus, the production of virulence determinants such as cell wall adhesins and exotoxins during the growth cycle is controlled by global regulators such as SarA and agr. Genomic scan reveals 16 two-component regulatory systems (e.g. agr and sae) as well as a family of SarA homologs in S. aureus. We call the SarA homologs the SarA protein family. Many of the members in this protein family are either small basic proteins (<153 residues) or two-domain proteins in which a single domain shares sequence similarity to each of the small basic proteins. Recent crystal structures of SarR and SarA reveal dimeric structures for these proteins. Because of its structure and unique mode of DNA binding, SarR, and possibly other SarA family members, may belong to a new functional class of the winged-helix family, accommodating long stretch of DNA with bending points. Based on sequence homology, we hypothesize that the SarA protein family may entail homologous structures with similar DNA-binding motifs but divergent activation domains. An understanding of how these regulators interact with each other in vivo and how they sense environmental signals to control virulence gene expression (e.g. alpha-hemolysin) will be important to our eventual goal of disrupting the regulatory network.

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Isolation and Characterization of a sigB Deletion Mutant of Staphylococcus aureus

Cited by 90 publications

References 22 publications

Formation of Staphylococcus aureus Biofilm in the Presence of Sublethal Concentrations of Disinfectants Studied via a Transcriptomic Analysis Using Transcriptome Sequencing (RNA-seq)

Formation of Staphylococcus aureus Biofilm in the Presence of Sublethal Concentrations of Disinfectants Studied via a Transcriptomic Analysis Using Transcriptome Sequencing (RNA-seq)

Impact of the regulatory loci agr, sarA and sae of Staphylococcus aureus on the induction of α‐toxin during device‐related infection resolved by direct quantitative transcript analysis

Global regulation of virulence determinants in Staphylococcus Aureus by the SarA protein family

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