Dysregulation of cell envelope homeostasis in Staphylococcus aureus exposed to solvated lignin
Ontology highlight
ABSTRACT:
ORGANISM(S): Staphylococcus aureus
PROVIDER: GSE198912 | GEO | 2022/07/12
REPOSITORIES: GEO
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Project description:The bacterial cell wall has been a celebrated target for antibiotics and holds real promise as a target for the discovery of new chemical matter to surmount pervasive multi-drug resistance among pathogenic bacteria. While the walls of Gram-negative bacteria are composed primarily of peptidoglycan, those of Gram-positives are more substantial and contain, in addition, large amounts of the polymer teichoic acid, covalently attached to peptidoglycan. Wall teichoic acids are a diverse group of phosphate-rich, extracellular polysaccharides that have been largely regarded as ancillary cell surface components. Recently, wall teichoic acid was shown to be essential to the proper rod-shaped cell morphology of the prototype Gram-positive bacterium Bacillus subtilis and an important virulence factor for the human pathogen Staphylococcus aureus. Thus wall teichoic acid synthesis is an intriguing target for the development of new cell wall-active antibiotics. Nevertheless, recent studies have shown that the dispensability of genes encoding teichoic acid biosynthetic enzymes in both B. subtilis and S. aureus is paradoxical and complex. Here, we report here on the discovery of a promoter (PywaC), which is sensitive to lesions in teichoic acid synthesis. Using this promoter we developed a luminescent, cell-based, reporter system to take a chemical-genetic approach to understanding the complexity of wall teichoic acid biogenesis using a large collection of antibiotics of well characterized biological activity. Our results reveal surprising interactions among undecaprenol, peptidoglycan and teichoic acid biosynthesis that help explain the complexity of teichoic acid gene dispensability. Furthermore, the new reporter assay represents an exciting avenue for the discovery of novel antibacterial molecules that impinge broadly on Gram-positive bacterial cell wall biogenesis. Keywords: comparison between depleted and repleted tagD mutant
2008-03-01 | GSE7373 | GEO
Project description:Objectives: Development of daptomycin resistance (DAPR) in Staphylococcus aureus is associated with clinical treatment failures. Mechanism(s) of such resistance has not been clearly defined. Methods: We studied an isogenic daptomycin-susceptible (DAPS) and daptomycin-resistant (DAPR) S. aureus strain pair (616; 701) from a patient with relapsing endocarditis during daptomycin treatment, using comparative transcriptomic and proteomic techniques. Results. Minor differences in genome content were found between strains by DNA hybridization. Transcriptomic analyses identified a number of genes differentially expressed in important functional categories: cell division, metabolism of bacterial envelopes and global regulation. Of note, the DAPR isolate exhibited reduced expression of the major cell wall autolysis gene coincident with upregulation of genes involved in wall teichoic acid production. Using quantitative (q)RT-PCR on gene cadre putatively involved in cationic peptide resistance, we formulated a putative regulatory network compatible with microarray data-sets, mainly implicating bacterial envelopes. Of interest, qRT-PCR of this same gene cadre from two distinct isogenic DAPS/DAPR clinical strain pairs revealed evidence of other strain dependent networks operative in the DAPR phenotype. Comparative proteomics of 616 vs 701 revealed differential abundance of proteins in various functional categories including: cell-wall associated targets and biofilm-formation proteins. Phenotypically, strains 616 and 701 showed major differences in ability to develop bacterial biofilms in presence of the antibacterial lipid, oleic acid. Conclusions: Compatible with previous in vitro observations, in vivo acquired DAPR in S. aureus is a complex, multistep phenomenon allowing for: i) strain dependent phenotypes; ii) transcriptome adaptation; and iii) modification of lipid and protein content of cellular envelopes. Daptomycin suceptible strain vs daptomycin non suceptible strain after daptomycin treatment
2011-12-02 | E-GEOD-28632 | biostudies-arrayexpress
Project description:<p>The discovery of antibiotics has led to the effective treatment of bacterial infections that were otherwise fatal and has had a transformative effect on modern medicine. Teixobactin is an unusual depsipeptide natural product that was recently discovered from a previously unculturable soil bacterium which is active against several Gram-positive pathogens, including methicillin- resistant Staphylococcus aureus and vancomycin-resistant Enterococci. One of the key attractive features of teixobactin as an antibiotic lead is that resistance could not be generated in a laboratory setting against S. aureus. This is proposed to be a result of the mechanism of action that involves binding to essential bacterial cell wall synthesis building blocks lipid II and lipid III.</p><p>In the present study, metabolomics was used to investigate the potential metabolic pathways and mode of action involved in mechanisms of antibacterial activity and bacterial killing of the synthetic teixobactin analog Leu10-teixobactin against an MRSA strain, S. aureus ATCC700699. The metabolomes of S. aureus ATCC700699 cells were compared at 1, 3 and 6 h following treatment with Leu10-teixobactin (0.5 µg/ml, i.e. 0.5x MIC) and the untreated controls. Leu10-teixobactin significantly perturbed bacterial membrane lipids (glycerophospholipids and fatty acids), peptidoglycan (lipid I and II) metabolism and cell wall teichoic acid (lipid III) biosynthesis as early as after 1 h of treatment reflecting an initial activity on the cell envelope. Concordant with its time-dependent antibacterial killing action, Leu10-teixobactin caused more perturbations in the levels of key intermediates in pathways of amino-sugar and nucleotide-sugar metabolism and their downstream peptidoglycan and teichoic acid biosynthesis at 3 and 6 h. Significant perturbations in arginine metabolism and interrelated tricarboxylic acid cycle, histidine metabolism, pantothenate and Coenzyme A biosynthesis were also observed at 3 and 6 h.</p><p>To conclude, this is the first study to provide novel metabolomics mechanistic information which lends to support the development of teixobactin as an antibacterial drug for the treatment of multi-drug resistant Gram-positive infections.</p>
2020-04-30 | MTBLS1569 | MetaboLights
Project description:Objectives: Development of daptomycin resistance (DAPR) in Staphylococcus aureus is associated with clinical treatment failures. Mechanism(s) of such resistance has not been clearly defined. Methods: We studied an isogenic daptomycin-susceptible (DAPS) and daptomycin-resistant (DAPR) S. aureus strain pair (616; 701) from a patient with relapsing endocarditis during daptomycin treatment, using comparative transcriptomic and proteomic techniques. Results. Minor differences in genome content were found between strains by DNA hybridization. Transcriptomic analyses identified a number of genes differentially expressed in important functional categories: cell division, metabolism of bacterial envelopes and global regulation. Of note, the DAPR isolate exhibited reduced expression of the major cell wall autolysis gene coincident with upregulation of genes involved in wall teichoic acid production. Using quantitative (q)RT-PCR on gene cadre putatively involved in cationic peptide resistance, we formulated a putative regulatory network compatible with microarray data-sets, mainly implicating bacterial envelopes. Of interest, qRT-PCR of this same gene cadre from two distinct isogenic DAPS/DAPR clinical strain pairs revealed evidence of other strain dependent networks operative in the DAPR phenotype. Comparative proteomics of 616 vs 701 revealed differential abundance of proteins in various functional categories including: cell-wall associated targets and biofilm-formation proteins. Phenotypically, strains 616 and 701 showed major differences in ability to develop bacterial biofilms in presence of the antibacterial lipid, oleic acid. Conclusions: Compatible with previous in vitro observations, in vivo acquired DAPR in S. aureus is a complex, multistep phenomenon allowing for: i) strain dependent phenotypes; ii) transcriptome adaptation; and iii) modification of lipid and protein content of cellular envelopes.
2011-12-02 | GSE28632 | GEO
Project description:The lantibiotic mersacidin is an antimicrobial peptide of 20 amino acids that is produced by Bacillus sp. strain HIL Y-85,54728. Lantibiotics are antibiotics containing nonproteinogenic amino acids like lanthionine and/or 3-methyllanthionine. Mersacidin interferes with cell wall biosynthesis by targeting the peptidoglycan precursor lipid II and inhibits the growth of MRSA and other gram-positive bacteria. Therefore, mersacidin could be a lead substance for the development of new antibacterial agents. The clinical VISA isolates S. aureus 137/93A and its spontaneous mutant S. aureus 137/93G show reduced sensitivity towards mersacidin. This phenotype could not be traced to factors being responsible for vancomycinresistance (i.e. the thickened cell wall). Here, we focussed on the comparative transcriptome analysis of S. aureus 137/93A and S. aureus SG511 (sensitive strain) via full genome S. aureus microarrays to identify genes involved in the reduced sensitivity towards mersacidin.
2009-01-17 | GSE12016 | GEO
Project description:Lomitapide has been approved by FDA for years in reducing levels of low-density lipoprotein (LDL) in cases of familial hypercholesterolemia, whereas the antibacterial effect of lomitapide remains elusive. In this study, the inhibitory activities of lomitapide against Staphylococcus aureus, including both methicillin sensitive and resistant S. aureus, were first time discovered by drug repositioning. Lomitapide has shown the inhibitory activities not only on the planktonic cell growth but also on the biofilm formation of S. aureus. Moreover, lomitapide has shown mild bactericidal effect on planktonic cells of clinical S. aureus strains as indicated in time killing assay. In order to investigate the mechanism of actions of lomitapide, quantitative proteomics analysis was then applied and suggested that the pathways involved in the cell wall biosynthesis and protein biosynthesis might participate in its action mode, whereas the clinical applications of lomitapide antibacterial activities need to be extensive investigated.
2022-03-29 | PXD031706 | Pride
Project description:Wall teichoic acids (WTAs) are phosphate-rich, sugar-based polymers attached to the cell walls of most Gram-positive bacteria. In Staphylococcus aureus, these anionic polymers regulate cell division, protect cells from osmotic stress, mediate host colonization, and mask enzymatically susceptible peptidoglycan bonds. Although WTAs are not required for survival in vitro, blocking the pathway at a late stage of synthesis is lethal. We recently discovered a novel antibiotic, targocil, that inhibits a late acting step in the WTA pathway. Its target is TarG, the transmembrane component of the ABC transporter (TarGH) that exports WTAs to the cell surface. Here we examine the effects of targocil on S. aureus using transmission electron microscopy (TEM) and gene expression profiling. We report that targocil treatment leads to multicellular clusters containing swollen cells displaying evidence of osmotic stress, strongly induces the cell wall stress stimulon, and reduces the expression of key virulence genes, including dltABCD and capsule genes. We conclude that WTA inhibitors that act at a late stage of the biosynthetic pathway may be useful as antibiotics, and we present evidence that they could be particularly useful in combination with beta-lactams. Growth conditions for microarray analysis-For transcriptional profiling, an overnight S. aureus SH1000 culture was diluted (2% (v/v) into 20 mL TSB medium in a 50 mL Erlenmeyer flask and grown at 37 °C with shaking at 200 rpm. For the targocil treatment experiments, S. aureus was grown to an OD600 ~0.4 and challenged with 8x MIC of targocil dissolved in DMSO) for 30 min. Simultaneously, an equal amount of DMSO (final concentration 2% (v/v)) was added to the control culture, which was incubated along with the treated cultures. After 30 min, 5 mL aliquots were collected from control and treated cultures and used for toatl RNA preparation.
2012-01-12 | E-GEOD-34441 | biostudies-arrayexpress
Project description:Staphylococcus aureus is a leading cause of hospital- and community-associated infections. The organism’s ability to cause disease can, in part, be attributable to its ability to adapt to otherwise deleterious host-associated stresses. Like other bacterial species, the modulation of mRNA turnover appears to play an important role in S. aureus adaptation to certain environmental stresses. In the current study Affymetrix GeneChips® were used to examine the S. aureus responses to acid and alkaline shock-inducing conditions and to assess whether stress dependent changes in mRNA turnover are likely to facilitate the organism’s ability to tolerate extreme pH challenge. Results indicate that S. aureus adapts to pH shock by eliciting responses expected of organisms coping with pH alteration, including neutralizing cellular internal pH, DNA repair, amino acid biosynthesis and virulence factor expression. Further, it was found that the cellular response to alkaline conditions elicits a transcriptional profile that is similar to that of stringent response induced cells. Consistent with that observation, we show that the activator of the stringent response, (p)ppGpp, levels are profoundly elevated during alkaline shock conditions. We also show that the mRNA turnover properties of acid or alkaline shocked cells significantly differ from that of cells grown at neutral pH. A comparison of the mRNA degradation properties of transcripts whose titers either increased or decreased in response to sudden pH change revealed that alterations in mRNA degradation may, in part, account for the changes in the mRNA levels of factors predicted to mediate pH tolerance. Finally, a set of small stable RNA molecules were induced in response to acid or alkaline shock conditions. As in other organisms, these molecules may mediate mRNA stability and adaptation to otherwise deleterious growth conditions.
2010-10-01 | GSE22233 | GEO
Project description:Staphylococcus aureus is a leading cause of hospital- and community-associated infections. The organism’s ability to cause disease can, in part, be attributable to its ability to adapt to otherwise deleterious host-associated stresses. Like other bacterial species, the modulation of mRNA turnover appears to play an important role in S. aureus adaptation to certain environmental stresses. In the current study Affymetrix GeneChips® were used to examine the S. aureus responses to acid and alkaline shock-inducing conditions and to assess whether stress dependent changes in mRNA turnover are likely to facilitate the organism’s ability to tolerate extreme pH challenge. Results indicate that S. aureus adapts to pH shock by eliciting responses expected of organisms coping with pH alteration, including neutralizing cellular internal pH, DNA repair, amino acid biosynthesis and virulence factor expression. Further, it was found that the cellular response to alkaline conditions elicits a transcriptional profile that is similar to that of stringent response induced cells. Consistent with that observation, we show that the activator of the stringent response, (p)ppGpp, levels are profoundly elevated during alkaline shock conditions. We also show that the mRNA turnover properties of acid or alkaline shocked cells significantly differ from that of cells grown at neutral pH. A comparison of the mRNA degradation properties of transcripts whose titers either increased or decreased in response to sudden pH change revealed that alterations in mRNA degradation may, in part, account for the changes in the mRNA levels of factors predicted to mediate pH tolerance. Finally, a set of small stable RNA molecules were induced in response to acid or alkaline shock conditions. As in other organisms, these molecules may mediate mRNA stability and adaptation to otherwise deleterious growth conditions. Staphylococcus aureus strain UAMS-1 was grown to exponential phase and either mock treated (pH maintained at 7.4) or subjected to acid (pH 4)- or alkaline (pH 10) conditions for 30 min. Next, 200 micrograms per ml of rifampicin were added to arrest transcript synthesis. RNA was extracted from cell suspensions at 0, 2.5, 5, 15, and 30 min post-transcriptional arrest, labeled and hybridized to S. aureus GeneChips. A comparison of 0 min samples allowed assessment of acid and alkaline shock responses. A comparison of 0 min to that of various post-transcriptional arrest RNA samples allowed assessment of the mRNA turnover properties of mock vs acid or alkaline shocked cells. Duplicates of each experimental condition and corresponding post-transcriptional arrest time point were used (biological replicates).
2010-10-01 | E-GEOD-22233 | biostudies-arrayexpress
Project description:The involvement of two R2R3-MYB genes from Pinus taeda L., PtMYB1 and PtMYB8, in phenylpropanoid metabolism and secondary cell wall biogenesis was investigated in planta. These pine MYBs were constitutively overexpressed (OE) in Picea glauca (Moench) Voss, used as a heterologous conifer expression system. Morphological, histological, chemical (lignin and soluble phenols), and transcriptional analyses, i.e. microarray and reverse transcription quantitative PCR (RT-qPCR) were used for extensive phenotyping of MYB-overexpressing spruce plantlets. Upon germination of somatic embryos, root growth was reduced in both transgenics. Enhanced lignin deposition was also a common feature but ectopic secondary cell wall deposition was more strongly associated with PtMYB8-OE. Microarray and RT-qPCR data showed that overexpression of each MYB led to an overlapping up-regulation of many genes encoding phenylpropanoid enzymes involved in lignin monomer synthesis, while misregulation of several cell wall-related genes and other MYB transcription factors was specifically associated with PtMYB8-OE. Together, the results suggest that MYB1 and MYB8 may be part of a conserved transcriptional network involved in secondary cell wall deposition in conifers.
2012-05-03 | E-MEXP-3626 | biostudies-arrayexpress