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León-Montes N, Nava-Galeana J, Rodríguez-Valverde D, Soria-Bustos J, Rosales-Reyes R, Rivera-Gutiérrez S, Hirakawa H, Ares MA, Bustamante VH, De la Cruz MA. The Two-Component System CpxRA Represses Salmonella Pathogenicity Island 2 by Directly Acting on the ssrAB Regulatory Operon. Microbiol Spectr 2022; 10:e0271022. [PMID: 36073960 PMCID: PMC9603713 DOI: 10.1128/spectrum.02710-22] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 08/15/2022] [Indexed: 01/04/2023] Open
Abstract
The acquisition of Salmonella pathogenicity island 2 (SPI-2) conferred on Salmonella the ability to survive and replicate within host cells. The ssrAB bicistronic operon, located in SPI-2, encodes the SsrAB two-component system (TCS), which is the central positive regulator that induces the expression of SPI-2 genes as well as other genes located outside this island. On the other hand, CpxRA is a two-component system that regulates expression of virulence genes in many bacteria in response to different stimuli that perturb the cell envelope. We previously reported that the CpxRA system represses the expression of SPI-1 and SPI-2 genes under SPI-1-inducing conditions by decreasing the stability of the SPI-1 regulator HilD. Here, we show that under SPI-2-inducing conditions, which mimic the intracellular environment, CpxRA represses the expression of SPI-2 genes by the direct action of phosphorylated CpxR (CpxR-P) on the ssrAB regulatory operon. CpxR-P recognized two sites located proximal and distal from the promoter located upstream of ssrA. Consistently, we found that CpxRA reduces the replication of Salmonella enterica serovar Typhimurium inside murine macrophages. Therefore, our results reveal CpxRA as an additional regulator involved in the intracellular lifestyle of Salmonella, which in turn adds a new layer to the intricate regulatory network controlling the expression of Salmonella virulence genes. IMPORTANCE SPI-2 encodes a type III secretion system (T3SS) that is a hallmark for the species Salmonella enterica, which is essential for the survival and replication within macrophages. Expression of SPI-2 genes is positively controlled by the two-component system SsrAB. Here, we determined a regulatory mechanism involved in controlling the overgrowth of Salmonella inside macrophages. In this mechanism, CpxRA, a two-component system that is activated by extracytoplasmic stress, directly represses expression of the ssrAB regulatory operon; as a consequence, expression of SsrAB target genes is decreased. Our findings reveal a novel mechanism involved in the intracellular lifestyle of Salmonella, which is expected to sense perturbations in the bacterial envelope that Salmonella faces inside host cells, as the synthesis of the T3SS-2 itself.
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Affiliation(s)
- Nancy León-Montes
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Jessica Nava-Galeana
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Diana Rodríguez-Valverde
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Jorge Soria-Bustos
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Roberto Rosales-Reyes
- Unidad de Medicina Experimental, Facultad de Medicina, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Sandra Rivera-Gutiérrez
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Hidetada Hirakawa
- Department of Bacteriology, Gunma University Graduate School of Medicine, Maebashi, Japan
| | - Miguel A. Ares
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Víctor H. Bustamante
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico
| | - Miguel A. De la Cruz
- Unidad de Investigación Médica en Enfermedades Infecciosas y Parasitarias, Hospital de Pediatría, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
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Cyclic di-GMP Positively Regulates DNA Repair in Vibrio cholerae. J Bacteriol 2018; 200:JB.00005-18. [PMID: 29610212 DOI: 10.1128/jb.00005-18] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 03/27/2018] [Indexed: 12/21/2022] Open
Abstract
In Vibrio cholerae, high intracellular cyclic di-GMP (c-di-GMP) concentration are associated with a biofilm lifestyle, while low intracellular c-di-GMP concentrations are associated with a motile lifestyle. c-di-GMP also regulates other behaviors, such as acetoin production and type II secretion; however, the extent of phenotypes regulated by c-di-GMP is not fully understood. We recently determined that the sequence upstream of the DNA repair gene encoding 3-methyladenine glycosylase (tag) was positively induced by c-di-GMP, suggesting that this signaling system might impact DNA repair pathways. We identified a DNA region upstream of tag that is required for transcriptional induction by c-di-GMP. We further showed that c-di-GMP induction of tag expression was dependent on the c-di-GMP-dependent biofilm regulators VpsT and VpsR. In vitro binding assays and heterologous host expression studies show that VpsT acts directly at the tag promoter in response to c-di-GMP to induce tag expression. Last, we determined that strains with high c-di-GMP concentrations are more tolerant of the DNA-damaging agent methyl methanesulfonate. Our results indicate that the regulatory network of c-di-GMP in V. cholerae extends beyond biofilm formation and motility to regulate DNA repair through the VpsR/VpsT c-di-GMP-dependent cascade.IMPORTANCEVibrio cholerae is a prominent human pathogen that is currently causing a pandemic outbreak in Haiti, Yemen, and Ethiopia. The second messenger molecule cyclic di-GMP (c-di-GMP) mediates the transitions in V. cholerae between a sessile biofilm-forming state and a motile lifestyle, both of which are important during V. cholerae environmental persistence and human infections. Here, we report that in V. cholerae c-di-GMP also controls DNA repair. We elucidate the regulatory pathway by which c-di-GMP increases DNA repair, allowing this bacterium to tolerate high concentrations of mutagens at high intracellular levels of c-di-GMP. Our work suggests that DNA repair and biofilm formation may be linked in V. cholerae.
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Ca 2+-Induced Two-Component System CvsSR Regulates the Type III Secretion System and the Extracytoplasmic Function Sigma Factor AlgU in Pseudomonas syringae pv. tomato DC3000. J Bacteriol 2018; 200:JB.00538-17. [PMID: 29263098 DOI: 10.1128/jb.00538-17] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 12/12/2017] [Indexed: 11/20/2022] Open
Abstract
Two-component systems (TCSs) of bacteria regulate many different aspects of the bacterial life cycle, including pathogenesis. Most TCSs remain uncharacterized, with no information about the signal(s) or regulatory targets and/or role in bacterial pathogenesis. Here, we characterized a TCS in the plant-pathogenic bacterium Pseudomonas syringae pv. tomato DC3000 composed of the histidine kinase CvsS and the response regulator CvsR. CvsSR is necessary for virulence of P. syringae pv. tomato DC3000, since ΔcvsS and ΔcvsR strains produced fewer symptoms than the wild type (WT) and demonstrated reduced growth on multiple hosts. We discovered that expression of cvsSR is induced by Ca2+ concentrations found in leaf apoplastic fluid. Thus, Ca2+ can be added to the list of signals that promote pathogenesis of P. syringae pv. tomato DC3000 during host colonization. Through chromatin immunoprecipitation followed by next-generation sequencing (ChIP-seq) and global transcriptome analysis (RNA-seq), we discerned the CvsR regulon. CvsR directly activated expression of the type III secretion system regulators, hrpR and hrpS, that regulate P. syringae pv. tomato DC3000 virulence in a type III secretion system-dependent manner. CvsR also indirectly repressed transcription of the extracytoplasmic sigma factor algU and production of alginate. Phenotypic analysis determined that CvsSR inversely regulated biofilm formation, swarming motility, and cellulose production in a Ca2+-dependent manner. Overall, our results show that CvsSR is a key regulatory hub critical for interaction with host plants.IMPORTANCE Pathogenic bacteria must be able to react and respond to the surrounding environment, make use of available resources, and avert or counter host immune responses. Often, these abilities rely on two-component systems (TCSs) composed of interacting proteins that modulate gene expression. We identified a TCS in the plant-pathogenic bacterium Pseudomonas syringae that responds to the presence of calcium, which is an important signal during the plant defense response. We showed that when P. syringae is grown in the presence of calcium, this TCS regulates expression of factors contributing to disease. Overall, our results provide a better understanding of how bacterial pathogens respond to plant signals and control systems necessary for eliciting disease.
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Sekhon SS, Ahn JY, Ahn JM, Park JM, Min J, Kim YH. Stress specific Escherichia coli biosensors based on gene promoters for toxicity monitoring. Mol Cell Toxicol 2015. [DOI: 10.1007/s13273-014-0041-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Xiang Z, Qin T, Qin ZS, He Y. A genome-wide MeSH-based literature mining system predicts implicit gene-to-gene relationships and networks. BMC SYSTEMS BIOLOGY 2013; 7 Suppl 3:S9. [PMID: 24555475 PMCID: PMC3852244 DOI: 10.1186/1752-0509-7-s3-s9] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Background The large amount of literature in the post-genomics era enables the study of gene interactions and networks using all available articles published for a specific organism. MeSH is a controlled vocabulary of medical and scientific terms that is used by biomedical scientists to manually index articles in the PubMed literature database. We hypothesized that genome-wide gene-MeSH term associations from the PubMed literature database could be used to predict implicit gene-to-gene relationships and networks. While the gene-MeSH associations have been used to detect gene-gene interactions in some studies, different methods have not been well compared, and such a strategy has not been evaluated for a genome-wide literature analysis. Genome-wide literature mining of gene-to-gene interactions allows ranking of the best gene interactions and investigation of comprehensive biological networks at a genome level. Results The genome-wide GenoMesh literature mining algorithm was developed by sequentially generating a gene-article matrix, a normalized gene-MeSH term matrix, and a gene-gene matrix. The gene-gene matrix relies on the calculation of pairwise gene dissimilarities based on gene-MeSH relationships. An optimized dissimilarity score was identified from six well-studied functions based on a receiver operating characteristic (ROC) analysis. Based on the studies with well-studied Escherichia coli and less-studied Brucella spp., GenoMesh was found to accurately identify gene functions using weighted MeSH terms, predict gene-gene interactions not reported in the literature, and cluster all the genes studied from an organism using the MeSH-based gene-gene matrix. A web-based GenoMesh literature mining program is also available at: http://genomesh.hegroup.org. GenoMesh also predicts gene interactions and networks among genes associated with specific MeSH terms or user-selected gene lists. Conclusions The GenoMesh algorithm and web program provide the first genome-wide, MeSH-based literature mining system that effectively predicts implicit gene-gene interaction relationships and networks in a genome-wide scope.
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Gul N, Linares DM, Ho FY, Poolman B. Evolved Escherichia coli strains for amplified, functional expression of membrane proteins. J Mol Biol 2013; 426:136-49. [PMID: 24041572 DOI: 10.1016/j.jmb.2013.09.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 09/08/2013] [Accepted: 09/10/2013] [Indexed: 10/26/2022]
Abstract
The major barrier to the physical characterization and structure determination of membrane proteins is low protein yield and/or low functionality in recombinant expression. The enteric bacterium Escherichia coli is the most widely employed organism for producing recombinant proteins. Beside several advantages of this expression host, one major drawback is that the protein of interest does not always adopt its native conformation and may end up in large insoluble aggregates. We describe a robust strategy to increase the likelihood of overexpressing membrane proteins in a functional state. The method involves fusion in tandem of green fluorescent protein and the erythromycin resistance protein (23S ribosomal RNA adenine N-6 methyltransferase, ErmC) to the C-terminus of a target membrane protein. The fluorescence of green fluorescent protein is used to report the folding state of the target protein, whereas ErmC is used to select for increased expression. By gradually increasing the erythromycin concentration of the medium and testing different membrane protein targets, we obtained a number of evolved strains of which four (NG2, NG3, NG5 and NG6) were characterized and their genome was fully sequenced. Strikingly, each of the strains carried a mutation in the hns gene, whose product is involved in genome organization and transcriptional silencing. The degree of expression of (membrane) proteins correlates with the severity of the hns mutation, but cells in which hns was deleted showed an intermediate expression performance. We propose that (partial) removal of the transcriptional silencing mechanism changes the levels of proteins essential for the functional overexpression of membrane proteins.
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Affiliation(s)
- Nadia Gul
- Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, Netherlands Proteomics Centre and Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Daniel M Linares
- Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, Netherlands Proteomics Centre and Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Franz Y Ho
- Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, Netherlands Proteomics Centre and Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands
| | - Bert Poolman
- Department of Biochemistry, University of Groningen, Groningen Biomolecular Sciences and Biotechnology Institute, Netherlands Proteomics Centre and Zernike Institute for Advanced Materials, Nijenborgh 4, 9747 AG Groningen, The Netherlands.
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Detrimental effects of hypoxia-specific expression of uracil DNA glycosylase (Ung) in Mycobacterium smegmatis. J Bacteriol 2010; 192:6439-46. [PMID: 20971917 DOI: 10.1128/jb.00679-10] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mycobacterium tuberculosis is known to reside latently in a significant fraction of the human population. Although the bacterium possesses an aerobic mode of metabolism, it adapts to persistence under hypoxic conditions such as those encountered in granulomas. While in mammalian systems hypoxia is a recognized DNA-damaging stress, aspects of DNA repair in mycobacteria under such conditions have not been studied. We subjected Mycobacterium smegmatis, a model organism, to the Wayne's protocol of hypoxia. Analysis of the mRNA of a key DNA repair enzyme, uracil DNA glycosylase (Ung), by real-time reverse transcriptase PCR (RT-PCR) revealed its downregulation during hypoxia. However, within an hour of recovery of the culture under normal oxygen levels, the Ung mRNA was restored. Analysis of Ung by immunoblotting and enzyme assays supported the RNA analysis results. To understand its physiological significance, we misexpressed Ung in M. smegmatis by using a hypoxia-responsive promoter of narK2 from M. tuberculosis. Although the misexpression of Ung during hypoxia decreased C-to-T mutations, it compromised bacterial survival upon recovery at normal oxygen levels. RT-PCR analysis of other base excision repair gene transcripts (UdgB and Fpg) suggested that these DNA repair functions also share with Ung the phenomenon of downregulation during hypoxia and recovery with return to normal oxygen conditions. We discuss the potential utility of this phenomenon in developing attenuated strains of mycobacteria.
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Abstract
The Cpx two-component signal transduction pathway of Escherichia coli mediates adaptation to envelope protein misfolding. However, there is experimental evidence that at least 50 genes in 34 operons are part of the Cpx regulon and many have functions that are undefined or unrelated to envelope protein maintenance. No comprehensive analysis of the Cpx regulon has been presented to date. In order to identify strongly Cpx-regulated genes that might play an important role(s) in envelope protein folding and/or to further define the role of the Cpx response and to gain insight into what makes a gene subject to strong Cpx regulation, we have carried out a uniform characterization of a Cpx-regulated lux reporter library in a single-strain background. Strongly Cpx-regulated genes encode proteins that are directly linked to envelope protein folding, localized to the envelope but uncharacterized, or involved in limiting the cellular concentration of noxious molecules. Moderately Cpx-regulated gene clusters encode products implicated in biofilm formation. An analysis of CpxR binding sites in strongly regulated genes indicates that while neither a consensus match nor their orientation predicts the strength of Cpx regulation, most genes contain a CpxR binding site within 100 bp of the transcriptional start site. Strikingly, we found that while there appears to be little overlap between the Cpx and Bae envelope stress responses, the sigma(E) and Cpx responses reciprocally regulate a large group of strongly Cpx-regulated genes, most of which are uncharacterized.
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MacRitchie DM, Buelow DR, Price NL, Raivio TL. Two-component signaling and gram negative envelope stress response systems. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2008; 631:80-110. [PMID: 18792683 DOI: 10.1007/978-0-387-78885-2_6] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- Dawn M MacRitchie
- Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada
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The response regulator CpxR directly regulates expression of several Legionella pneumophila icm/dot components as well as new translocated substrates. J Bacteriol 2008; 190:1985-96. [PMID: 18192394 DOI: 10.1128/jb.01493-07] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Legionella pneumophila has been shown to utilize the icm/dot type IV secretion system for pathogenesis. This system was shown to be composed of icm/dot complex components and accessory proteins, as well as a large number of translocated substrates. Bioinformatic analysis of the regulatory regions of all the genes revealed that several icm/dot genes, as well as two genes encoding icm/dot translocated substrates, contain the conserved CpxR regulatory element, a regulator that has been shown previously to control the expression of the icmR gene. An experimental analysis, which included a comparison of gene expression in a L. pneumophila wild-type strain and gene expression in a cpxR deletion mutant, construction of mutants with mutations in the CpxR conserved regulatory elements, controlled expression studies, and mobility shift assays, demonstrated the direct relationship between the CpxR regulator and the expression of the genes. Furthermore, genomic analysis identified nine additional genes that contain a putative CpxR regulatory element; five of these genes (two legA genes and three ceg genes) were suggested previously to be putative icm/dot translocated substrates. The three ceg genes identified, which were shown previously to contain a putative PmrA regulatory element, were found here to be regulated by both CpxR and PmrA. The other six genes (two legA genes and four new genes products were found to be regulated by CpxR. Moreover, using the CyaA translocation assay, these nine gene products were found to be translocated into host cells in an Icm/Dot-dependent manner. Our results establish that the CpxR regulator is a fundamental regulator of the icm/dot type IV secretion system in L. pneumophila.
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Yamamoto K, Ogasawara H, Ishihama A. Involvement of multiple transcription factors for metal-induced spy gene expression in Escherichia coli. J Biotechnol 2008; 133:196-200. [PMID: 17884222 DOI: 10.1016/j.jbiotec.2007.08.002] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2007] [Revised: 06/16/2007] [Accepted: 08/01/2007] [Indexed: 11/23/2022]
Abstract
Bacteria are directly exposed to metals in environment. To maintain the intracellular metal homeostasis, Escherichia coli contain a number of gene regulation systems, each for response to a specific metal. A periplasmic protein Spy of E. coli was found to be induced upon short-exposure to copper ion in CpxAR-dependent manner. Transcription of the spy gene was also induced by long-exposure to zinc ion. This induction, however, depended on another two-component system BaeSR. Using DNase-I footprinting assay, we identified two BaeR-binding regions on the spy promoter with a direct repeat of the BaeR-box sequence, TCTNCANAA. The zinc-responsive BaeR-binding sites were separated from copper-responsive CpxR-binding site, implying that the spy promoter responds to two species of metal independently through different using sensor-response regulator systems. Since BaeSR-dependent zinc response requires longer time, the induction of spy gene transcription by external zinc may include multiple steps such as through sensing the zinc-induced envelope disorder by BaeSR.
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Affiliation(s)
- Kaneyoshi Yamamoto
- Department of Advanced Bioscience, Kinki University, Nakamachi, Nara, Japan
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Saint-Ruf C, Pesut J, Sopta M, Matic I. Causes and consequences of DNA repair activity modulation during stationary phase in Escherichia coli. Crit Rev Biochem Mol Biol 2007; 42:259-70. [PMID: 17687668 DOI: 10.1080/10409230701495599] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Escherichia coli responds to nutrient exhaustion by entering a state commonly referred to as the stationary phase. Cells entering the stationary phase redirect metabolic circuits to scavenge any available nutrients and become resistant to different stresses. However, many DNA repair pathways are downregulated in stationary-phase cells, which results in increased mutation rates. DNA repair activity generally depends on consumption of energy and often requires de novo proteins synthesis. Consequently, unless stringently regulated during stationary phase, DNA repair activities may lead to an irreversible depletion of energy sources and, therefore to cell death. Most stationary phase morphological and physiological modifications are regulated by an alternative RNA polymerase sigma factor RpoS. However, nutrient availability, and the frequency and nature of stresses, are different in distinct environmental niches, which impose conflicting choices that result in selection of the loss or of the modification of RpoS function. Consequently, DNA repair activity, which is partially controlled by RpoS, is differently modulated in different environments. This results in the variable mutation rates among different E. coli ecotypes. Hence, the polymorphism of mutation rates in natural E. coli populations can be viewed as a byproduct of the selection for improved fitness.
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Affiliation(s)
- Claude Saint-Ruf
- INSERM, U571, Faculté de Médicine, Université Paris 5, Paris, France
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Chang W, Toghrol F, Bentley WE. Toxicogenomic response of Staphylococcus aureus to peracetic acid. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2006; 40:5124-31. [PMID: 16955917 DOI: 10.1021/es060354b] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Staphylococcus aureus is responsible for many incidents of hospital-acquired infection, which causes 90,000 deaths and dollars 4.5 billion loss a year in the United States. Despite a wide use of disinfectants such as peracetic acid in health care environments, we certainly need better understanding of the effects of antimicrobial application on target pathogens to avert infection outbreaks. Consequently, herein, we explored for the first time the toxicogenomic response of S. aureus to a sublethal concentration of peracetic acid (1 mM) by using microarray-based transcriptome analysis. In particular, we investigated the dynamics of global gene expression profiles during its cellular response, which involved initial growth inhibition (10 min) and subsequent partial recovery (20 min). Further, we compared transcriptome responses to peracetic acid between S. aureus and Pseudomonas aeruginosa. Our findings show that (i) the regulation of membrane transport genes was significantly altered, (ii) DNA repair and replication genes were selectively induced, and (iii) primary metabolism-related genes were differently repressed between the two growth states. Most intriguingly, we revealed that many virulence factor genes were induced upon the exposure, which proposes a possibilitythatthe pathogenesis of S. aureus may be stimulated in response to peracetic acid.
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Affiliation(s)
- Wook Chang
- Center for Biosystems Research, University of Maryland Biotechnology Institute, College Park 20742, USA
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Prüss BM, Besemann C, Denton A, Wolfe AJ. A complex transcription network controls the early stages of biofilm development by Escherichia coli. J Bacteriol 2006; 188:3731-9. [PMID: 16707665 PMCID: PMC1482888 DOI: 10.1128/jb.01780-05] [Citation(s) in RCA: 129] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Affiliation(s)
- Birgit M Prüss
- Department of Veterinary and Microbiological Sciences, North Dakota State University, 1523 Centennial Blvd., Fargo, ND 58105, USA.
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Dorel C, Lejeune P, Rodrigue A. The Cpx system of Escherichia coli, a strategic signaling pathway for confronting adverse conditions and for settling biofilm communities? Res Microbiol 2006; 157:306-14. [PMID: 16487683 DOI: 10.1016/j.resmic.2005.12.003] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2005] [Revised: 12/22/2005] [Accepted: 12/22/2005] [Indexed: 01/15/2023]
Abstract
Amongst the thirty or so two-component systems known in Escherichia coli, the Cpx system has been described as being a stress response system the main function of which is to respond to damage to the cell envelope via activation of proteases and folding catalysts. Nevertheless, the size of the Cpx regulon (several dozens of target genes) and the diversity of the physiological functions associated with it (resistance to hostile conditions, mobility, adherence factors, metabolism, etc.) indicate that the role of Cpx in cell physiology is undoubtedly more complex. The range of cellular functions affected by activation of the Cpx pathway corresponds quite closely to the description of the physiological state of cells grown in biofilms. We suggest that Cpx is a strategic signaling pathway for facing adverse conditions and for settling biofilm communities. Current knowledge of the regulatory mechanisms of the CpxR response (transcriptional and post-transcriptional) and the interactions between CpxR and the other bacterial regulatory systems are presented.
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Affiliation(s)
- Corinne Dorel
- Unité de Microbiologie et Génétique Composante INSA, UMR CNRS 5122, Université Claude Bernard Lyon I, 10 rue Dubois, 69 622 Villeurbanne cedex, France.
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