The iron starvation response of the Staphylococcus aureus hemB small colony variant (SCV)
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PROVIDER: PRJNA763127 | ENA |
REPOSITORIES: ENA
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Project description:Respiration deficient S. aureus small colony variants (SCVs) frequently cause persistent infections, which necessitates they acquire iron, yet how SCVs obtain iron remains unknown. To address this, we created a stable hemB mutant in S. aureus USA300 strain LAC. The hemB SCV utilized exogenously supplied heme but was attenuated for growth under conditions of iron starvation. RNA-seq showed that both WT S. aureus and the hemB mutant sense and respond to iron starvation.
2022-09-06 | GSE184082 | GEO
Project description:Transcriptional profiling of the small colony variant (SCV) S. aureus isolate (JKD6229) compared to the parent isolate with a normal phenotype (JKD6210). Both isolates were from a patient with persistent S. aureus infection, and the SCV strain arose during failed antibiotic therapy.
2010-08-13 | GSE20957 | GEO
Project description:Transcriptional profiling of the small colony variant (SCV) S. aureus isolate (JKD6229) compared to the parent isolate with a normal phenotype (JKD6210). Both isolates were from a patient with persistent S. aureus infection, and the SCV strain arose during failed antibiotic therapy. Two condition experiment JKD6229 vs JKD6210. 4 biological replicates, one replicate per slide.
2010-08-13 | E-GEOD-20957 | biostudies-arrayexpress
Project description:In this study we have profiled a clinical tobramycin resistant P. aeruginosa strain that exhibited a small colony variant (SCV) phenotype. Both, the resistance and the colony morphology phenotypes were lost upon passaging the isolate under rich medium conditions. Transcriptional and mutational profiling revealed that the SCV harbored activating mutations in the two two-component systems AmgRS and PmrAB. Introduction of these mutations singularly into the type strain PA14 conferred tobramycin and colistin resistance, respectively. However, their combined introduction had an additive effect on the tobramycin resistance phenotype. Activation of the AmgRS system slightly reduced the colony size of the PA14 wild-type, whereas the simultaneous overexpression of gacA, the response regulator of the GacSA two component system, further reduced colony size. In conclusion, we uncovered combinatorial influences of two-component systems on clinically relevant phenotypes, such as resistance and the expression of the SCV phenotype. Our results clearly demonstrate that combined activation of P. aeruginosa two-component systems exhibit pleiotropic effects with unforeseen consequences.
2017-08-22 | GSE99729 | GEO
Project description:To better understand transcriptional changes in the SCV, RNA-seq analyses were conducted by comparing a SCV mutant to the wild-type. Transcriptomic profiling identified more than 1000 genes indicating a significant reprograming of gene expression in the SCV mutant. In accordance with observed phenotypes, genes involved in metabolism functions, motility and phenazine production were downregulated; whereas, oxidative stress and iron uptake genes were significantly upregulated.
2014-11-25 | GSE51293 | GEO
Project description:To better understand transcriptional changes in the SCV, RNA-seq analyses were conducted by comparing a SCV mutant to the wild-type. Transcriptomic profiling identified more than 1000 genes indicating a significant reprograming of gene expression in the SCV mutant. In accordance with observed phenotypes, genes involved in metabolism functions, motility and phenazine production were downregulated; whereas, oxidative stress and iron uptake genes were significantly upregulated. A total of 5 samples were analyzed in AB medium + 2% casamino acids, Pseudomonas chlororaphis wild type strain (3 replicates); Pseudomonas chlororaphis SCV mutant (2 replicates).
2014-11-25 | E-GEOD-51293 | biostudies-arrayexpress
Project description:Background Small colony variants (SCVs) are slow-growing bacteria, which often show increased resistance to antibiotics and cause latent or recurrent infections. It is therefore important to understand the mechanisms at the basis of this phenotypic switch. Methodology/Principal findings One SCV (termed PAO-SCV) was isolated, showing high resistance to gentamicin and to the cephalosporine cefotaxime. PAO-SCV was prone to reversion as evidenced by emergence of large colonies with a frequency of 10-5 on media without antibiotics while it was stably maintained in presence of gentamicin. PAO-SCV showed a delayed growth, defective motility, and strongly reduced levels of the quorum sensing Pseudomonas quinolone signal (PQS). Whole genome expression analysis further suggested a multi-layered antibiotic resistance mechanism, including simultaneous over-expression of two drug efflux pumps (MexAB-OprM, MexXY-OprM), the LPS modification operon arnBCADTEF, and the PhoP-PhoQ two-component system. Conversely, the genes for the synthesis of PQS were strongly down-regulated in PAOSCV. Finally, genomic analysis revealed the presence of mutations in phoP and phoQ genes as well as in the mexZ gene encoding a repressor of the mexXY and mexABoprM genes. Only one mutation occurred only in REV, at nucleotide 1020 of the tufA gene, a paralog of tufB, both encoding the elongation factor Tu, causing a change of the rarely used aspartic acid codon GAU to the more common GAC, possibly causing an increase of tufA mRNA translation. High expression of phoP and phoQ was confirmed for the SCV variant while the revertant showed expression levels reduced to wild-type levels. Conclusions By combining data coming from phenotypic, gene expression and proteome analysis, we could demonstrate that resistance to aminoglycosides in one SCV mutant is multifactorial including overexpression of efflux mechanisms, LPS modification and is accompanied by a drastic down-regulation of the Pseudomonas quinolone signal quorum sensing system. We used microarrays to study changes in gene expression during early and late stationary phase of SCV and WT strains. SCV and WT cultures were grown in triplicate until early (24h) and late (48h) stationary phase. RNA was extracted, labelled and hybridised on Affymetrix P. aeruginosa expression microarrays.
2011-12-06 | E-GEOD-34141 | biostudies-arrayexpress
Project description:Background Small colony variants (SCVs) are slow-growing bacteria, which often show increased resistance to antibiotics and cause latent or recurrent infections. It is therefore important to understand the mechanisms at the basis of this phenotypic switch. Methodology/Principal findings One SCV (termed PAO-SCV) was isolated, showing high resistance to gentamicin and to the cephalosporine cefotaxime. PAO-SCV was prone to reversion as evidenced by emergence of large colonies with a frequency of 10-5 on media without antibiotics while it was stably maintained in presence of gentamicin. PAO-SCV showed a delayed growth, defective motility, and strongly reduced levels of the quorum sensing Pseudomonas quinolone signal (PQS). Whole genome expression analysis further suggested a multi-layered antibiotic resistance mechanism, including simultaneous over-expression of two drug efflux pumps (MexAB-OprM, MexXY-OprM), the LPS modification operon arnBCADTEF, and the PhoP-PhoQ two-component system. Conversely, the genes for the synthesis of PQS were strongly down-regulated in PAOSCV. Finally, genomic analysis revealed the presence of mutations in phoP and phoQ genes as well as in the mexZ gene encoding a repressor of the mexXY and mexABoprM genes. Only one mutation occurred only in REV, at nucleotide 1020 of the tufA gene, a paralog of tufB, both encoding the elongation factor Tu, causing a change of the rarely used aspartic acid codon GAU to the more common GAC, possibly causing an increase of tufA mRNA translation. High expression of phoP and phoQ was confirmed for the SCV variant while the revertant showed expression levels reduced to wild-type levels. Conclusions By combining data coming from phenotypic, gene expression and proteome analysis, we could demonstrate that resistance to aminoglycosides in one SCV mutant is multifactorial including overexpression of efflux mechanisms, LPS modification and is accompanied by a drastic down-regulation of the Pseudomonas quinolone signal quorum sensing system. We used microarrays to study changes in gene expression during early and late stationary phase of SCV and WT strains.
2011-12-06 | GSE34141 | GEO
Project description:Burkholderia pseudomallei is the causative agent of melioidosis which is endemic to Southeast Asia and Northern Australia. It is a Gram-negative soil and water bacterium that represents a potential bioterrorism threat. Colony morphology variation is a remarkable feature in primary clinical cultures of B. pseudomallei. Differences in expression of several potential virulence and survival genes were believed to be associated with B. pseudomallei colony morphology variants. Microarrray approach was used to investigate alterations of the global B. pseudomallei transcriptome profile at the mid-logarithmic phase of growth, among the wild type (WT) and small colony variant (SCV) of B. pseudomallei pre- and post-exposed to human lung epithelial cells, A549. Generally, SCV pre- and post-exposed have lower metabolic requirements and consume lesser energy than WT pre- and post-exposed to A549; however, both WT and SCV may limit their metabolic activity during the infection of A549 cells and this is indicated by the down-regulation of genes implicated in metabolism of amino acids, carbohydrate, lipid, and other amino acids, and biodegradation of xenobiotics. On the other hand, many well-known virulence and survival factors including T3SS, T6SS, fimbriae, capsular polysaccharides, drug resistance and stress response were up-regulated in both WT and SCV pre- and post-exposed to A549 cells. Several virulence factors expressed at the mid-logarithmic phase of growth. Microarray analysis on the different morphotypes demonstrated the essential difference in bacterial response associated with virulence and survival pre- and post-exposed to A549 cells.
2016-10-12 | GSE87827 | GEO
Project description:Transcriptional time series of Candida glabrata under iron starvation (SD medium without Fe). Wild type and deletion mutants of the iron-related transcription factors Aft1 and Sef1, as well as of the iron uptake transporter Ftr1 as a positive control.
2016-10-05 | GSE84816 | GEO