Staphylococcus aureus
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ABSTRACT:
PROVIDER: PRJNA108363 | ENA |
REPOSITORIES: ENA
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Project description:The study aims to compare gene expression patterns of Staphyloccoccus aureus USA300 wild type (reference) vs USA300 agr knockout(query). The agr quorum sensing system is an important regulator of density dependent gene expression. To determine the role of agr in USA300 virulence a agr mutant was constructed and differential gene expression compared to the parental wildtype.
2011-04-08 | GSE26254 | GEO
Project description:RNAseq of exponentially growing cultures of the four agr prototype strains used in the study to investigate if differential expression of regulators interacting with the agr system could explain the differences in AIP sensitivity. Abstract Staphylococcus aureus both colonizes humans and causes severe virulent infections. Virulence is regulated by the agr quorum sensing system and its autoinducing peptide (AIP), with dynamics at the single-cell level across four agr-types – each defined by distinct AIP sequences and capable of cross-inhibition – remaining elusive. Employing microfluidics, time-lapse microscopy, and deep-learning image analysis, we uncovered significant differences in AIP sensitivity among agr-types. We observed bimodal agr activation, attributed to intergenerational phenotypic stability and influenced by AIP concentration. Upon AIP stimulation, agr III showed AIP insensitivity, while agr II exhibited increased sensitivity and prolonged generation time. Beyond expected cross-inhibition of agr I by heterologous AIP II and III, the presumably cross-activating AIP IV also inhibited agr I. Community interactions across different agr-type pairings revealed four main patterns: stable or switched dominance, and delayed or stable dual activation, influenced by community characteristics. These insights underscore the potential of personalized treatment strategies considering virulence and genetic diversity.
2024-03-05 | E-MTAB-13859 | biostudies-arrayexpress
Project description:The fungal metabolite apicidin acts as a quorum sensing inhibitor in Staphylococcus aureus. Here we use RNA-sequencing to examine the effect of apicidin on gene expression, comparing to untreated wild-type and an agr quorum sensing mutant.
2019-01-29 | GSE125741 | GEO
Project description:CodY is a conserved regulator in gram-positive organisms described to repress metabolic genes mainly involved in nitrogen metabolism but also to control the expression of virulence genes in pathogens. We constructed codY gene-replacement mutants in three unrelated S. aureus strains (Newman, UAMS-1, RN1HG). codY mutants grew slower in a chemically defined medium compared to the wild type strains. However, only codY mutants were able to grow in medium lacking threonine. Excess of isoleucine resulted in growth inhibition in the wild type but not in the codY mutants indicating a role of isoleucine for CodY dependent repression of metabolic genes. The prototypic CodY-repressed operon ilvDBCleuABCilvA is preceded by a CodY-binding motif and repressed after up-shift with isoleucine and to a lesser extent guanidine. Transcription of the quorum sensing system agr followed a similar expression pattern. The codY dependent repression of agr is in line with the concomitant influence of CodY on typical agr regulated genes such as cap, spa fnbA and coa. However, transcriptional analysis revealed that most of these virulence genes (e.g. cap, fnbA, spa hla) are also regulated by CodY in an agr negative background. Microarray analysis revealed the large majority of codY-repressed genes are involved in amino-acid transport and metabolism, genes showing codY dependent activation were mainly involved in nucleotide transport and metabolism or virulence. In summary, CodY in S. aureus not only acts as repressor for genes involved in nitrogen metabolism but also contributes to virulence gene regulation by supporting as well as substituting agr function. The microarray was manufactured by in situ synthesis of 10'807 long oligonucleotide probes , selected as previously described (Charbonnier, 2005). It covers >98% of all ORFs annotated in strains N315 and Mu50 , MW2, COL , NCTC8325, USA300 , MRSA252 an MSSA476 including their respective plasmids.
2008-11-06 | E-GEOD-12340 | biostudies-arrayexpress
Project description:Drug discovery for novel anti-infectives is essential to meet the global health threat of antibiotic resistant bacterial infections, including those caused by Staphylococcus aureus1,2. Because ~90% of S. aureus infections involve skin and soft tissues (SSTIs)3,4, we hypothesized that developing anti-virulence therapeutics5,6 for SSTIs could minimize pressure on resistance development while sparing conventional antibiotics for control of systemic infections. We identified a small molecule inhibitor that disrupted signaling by a quorum sensing operon, agr, associated with human SSTIs7,8 without affecting agr-independent growth.
2017-02-09 | GSE52978 | GEO
Project description:CodY is a conserved regulator in gram-positive organisms described to repress metabolic genes mainly involved in nitrogen metabolism but also to control the expression of virulence genes in pathogens. We constructed codY gene-replacement mutants in three unrelated S. aureus strains (Newman, UAMS-1, RN1HG). codY mutants grew slower in a chemically defined medium compared to the wild type strains. However, only codY mutants were able to grow in medium lacking threonine. Excess of isoleucine resulted in growth inhibition in the wild type but not in the codY mutants indicating a role of isoleucine for CodY dependent repression of metabolic genes. The prototypic CodY-repressed operon ilvDBCleuABCilvA is preceded by a CodY-binding motif and repressed after up-shift with isoleucine and to a lesser extent guanidine. Transcription of the quorum sensing system agr followed a similar expression pattern. The codY dependent repression of agr is in line with the concomitant influence of CodY on typical agr regulated genes such as cap, spa fnbA and coa. However, transcriptional analysis revealed that most of these virulence genes (e.g. cap, fnbA, spa hla) are also regulated by CodY in an agr negative background. Microarray analysis revealed the large majority of codY-repressed genes are involved in amino-acid transport and metabolism, genes showing codY dependent activation were mainly involved in nucleotide transport and metabolism or virulence. In summary, CodY in S. aureus not only acts as repressor for genes involved in nitrogen metabolism but also contributes to virulence gene regulation by supporting as well as substituting agr function.
2008-11-07 | GSE12340 | GEO
Project description:Compilation fo whole genome gene expression changes in Staphylococcus aureus USA300 LAC cultures grown in the presence of vehicle or the anti-gout drug benzbromarone. The drug was intially screened as effective against the agr quorum sensing system in Staphylococcus aureus AH1677.
2014-03-19 | GSE55980 | GEO
Project description:The agr quorum-sensing system clearly links Staphylococcus aureus metabolism to virulence, but little is known about how agr alters metabolism to affect cell survival during severe stress. Recently, we reported that agr activity increases survival of bacteria during treatment with lethal concentrations of H2O2, a crucial host defense against S. aureus. Here we report that protection by agr extends to growth resumption during the exit from stationary phase. The data indicate that the agr functionality of a cell’s ancestor affects stress-resiliency after resuming growth. Protection against killing by H2O2 depended on the agr effector molecule RNAIII and Rot, a transcription factor targeted by RNAIII. Expression data revealed that Δagr strains shift to fermentation, suggesting that agr promotes aerobic respiration. Epistasis between mutation of agr and sortase, which anchors surface proteins to the cell wall, suggested that reduced killing by H2O2 of wild-type agr strains acts through down-regulation of surface proteins that perturb respiration. Respiration generates reactive oxygen species (ROS), moderate amounts of which can protect from subsequent challenge by lethal concentrations, explaining agr-mediated protection against subsequent lethal H2O2 doses. Increased survival of wild-type agr cells in response to H2O2 required sodA, which dismutates O2- to H2O2, suggesting that sodA helps induce the low, protective levels of ROS triggered by agr. Additionally, detrimental effects of the Δagr mutation require ahpC, which functions to decrease the intracellular level of H2O2. Deletion of ahpC or sortase attenuated neutrophil-mediated killing of Δagr strains, demonstrating the importance of priming in anticipation of impending immune attack.
2023-06-20 | GSE206916 | GEO
Project description:The purpose of this study was to compare the global, growth phase-dependent transcriptional profiles of two isolates of Staphylococcus aureus. One isolate is a prototypic laboratory strain named RN6390, and has been used frequently as a model organism for study of staphylococcal physiology and virulence. However, recent studies indicate that RN6390 is not, in general, genotypically or phenotypically representative of clinical isolates of Staphyloccos aureus. Therefore, there is no current comprehensive picture of gene expression patterns in a virulent, clinical isolate of Staphyloccous aureus. For these reasons, we compare the transcriptional profile of RN6390 to that of a virulent clinical isolate, UAMS-1. Also included in this study is profiling of two UAMS-1 regulatory mutants, UAMS-155, and UAMS-929. These strains possess mutations in the accessory gene regulator (agr) and staphylococcal accessory regulator (sarA) genes, respectively. These two genes are well described global regulatory molecules that are reported to play important roles in controlling virulence factor production and biofilm formation in Staphylococcus aureus. However, most study of these two molecules has been limited to laboratory strains such as RN6390. For these reasons, this study also includes transcriptional profiling of UAMS agr and sarA mutants. Keywords: Comparative, growth phase-dependent transcriptional profiling of bacterial strains and isogenic regulatory mutants
2006-10-03 | GSE5466 | GEO
Project description:Staphylococcus hominis is frequently isolated from human skin and we hypothesize that it may protect the cutaneous barrier from opportunistic pathogens. We determined that S. hominis makes six unique auto inducing peptide (AIP) signals that inhibit the major virulence factor accessory gene regulator (agr) quorum sensing system of Staphylococcus aureus. We solved and confirmed the structures of three novel AIP signals in conditioned media by mass spectrometry, then validated synthetic AIP activity against all S. aureus agr classes. Synthetic AIPs also inhibited the conserved agr system in a related species, Staphylococcus epidermidis. We determined the distribution of S. hominis agr types on healthy human skin and found S. hominis agr-I and agr-II were highly represented across subjects. Further, synthetic AIP-II was protective in vivo against S. aureus-associated dermonecrotic or epicutaneous injury. Together, these findings demonstrate that a ubiquitous colonizer of human skin has a fundamentally protective role against opportunistic damage.
2022-04-04 | GSE199818 | GEO