Regulation of Energy Metabolism by the Extracytoplasmic Function (ECF) ? factors of Arcobacter butzleri
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ABSTRACT:
ORGANISM(S): Arcobacter butzleri RM4018
SUBMITTER: Craig Parker
PROVIDER: E-GEOD-34089 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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Project description:The extracytoplasmic function (ECF) σ factors are fundamental for bacterial adaptation to distinct environments and for survival under different stress conditions. The emerging pathogen Arcobacter butzleri possesses seven putative pairs of σ/anti-σ factors belonging to the ECF family. Here, we report the identification of the genes regulated by five out of the seven A. butzleri ECF σ factors. Three of the ECF σ factors play an apparent role in transport, energy generation and the maintainance of redox balance. Several genes like the nap, sox and tct genes are regulated by more than one ECF σ factor indicating that the A. butzleri ECF σ factors form a network of overlapping regulons. In contrast to other eubacteria, these A. butzleri ECF regulons appear to primarily regulate responses to changing environments in order to meet metabolic needs instead of an obvious role in stress adaptation.
2011-12-31 | GSE34089 | GEO
Project description:Two-component systems are widespread prokaryotic signal transduction devices which allow the regulation of cellular functions in response to changing environmental conditions. The two-component system DccRS (Cj1223-Cj1222) of Campylobacter jejuni is important for the colonization of chickens. Here we dissected the DccRS system in more detail and provide evidence that the sensor DccS selectively phosphorylates the cognate effector DccR. Microarray expression profiling, real-time RT-PCR, EMSA, and primer extension analyses revealed that the DccRS regulon of strain 81116 consists of five promoter elements all containing the consensus direct repeat sequence WTTCAC-N6-TTCACW covering the putative -35 promoter regions. One of these promoters is located in front of an operon encoding a putative macrolide efflux pump while the others are in front of genes coding for putative periplasmic or membrane proteins. The DccRS regulated genes in C. jejuni strain 81116 are needed to enhance early in vivo growth of C. jejuni in 7-day old chicken. The DccRS system is activated in the late stationary bacterial growth phase, probably via the release of metabolic products. Whole genome mRNA profiling and real-time RT-PCR analysis under these conditions demonstrated that the system has no influence on the transcription of genes outside the DccRS regulon. Two-condition experiment, C. jejuni strain WT81116 vs. C. jejuni strain 81116dccR::cm. Technical replicates: 3 WT81116, 3 81116dccR::cm, independently grown to stationary phase and harvested. One replicate per array. A type 2 gene expression experimental design was used, with fluorescently labeled genomic DNA as a reference channel in each experiment as described by Lucchini, S., et al. 2005. Infect Immun 73:88-102.
2010-01-09 | E-GEOD-19803 | biostudies-arrayexpress
Project description:We compared the transcriptional profiles of 12 E. coli O157:H7 isolates grown to stationary phase in LB broth. These isolates possess the same two enzyme PFGE profile and are related temporally or geographically to the above outbreak. These E. coli O157:H7 isolates included three clinical isolates, five isolates from separate bags of spinach, and single isolates from pasture soil, river water, cow feces, and a feral pig. Twelve condition experiment, 12 E. coli O157:H7 isolates. Two biological replicates for isolates RM6067, RM6069, RM6101, RM6102, RM6103, RM6149, RM6655, RM6658, RM9992, RM9997, RM9998 and RM10002 independently grown to stationary phase in LB at 37°C and harvested. One replicate per array. A type 2 gene expression experimental design was used, with fluorescently labeled genomic DNA as a reference channel in each experiment as described by Lucchini, S., et al. 2005. Infect Immun 73:88-102.
2011-11-01 | E-GEOD-33131 | biostudies-arrayexpress
Project description:Curli are adhesive fimbriae of Enterobactericaeae and are involved in surface attachment, cell aggregation and biofilm formation. We previously reported that natural curli variants of E. coli O157:H7 (EcO157) displayed distinct acid resistance; however, this difference was not linked to the curli fimbriae per se. Here, we investigated the underlying molecular basis of this phenotypic divergence between the curli variants. Among curli-producing (C+) variants isolated from the 1993 U.S. hamburger-associated outbreaks strains, we identified large deletions in the rcsB gene that encodes the response regulator of RcsCDB two-component signal transduction system of rcsB ,. Further comparison of stress fitness revealed that C+ variants were also significantly more sensitive to heat shock, but remained similar resistance to osmotic stress and oxidative damage as curli-deficient (C-) variants. Transcriptomics analysis uncovered a large number of differentially expressed genes between the curli variants, characterized by the enhanced expression of genes related to biofilm formation, virulence, catabolic activity and nutrients uptake, but marked decrease in transcription of genes related to various stress resistance in C+ variants. Supplying C+ variants with a functional rcsB restored cells resistance to heat shock and acid challenge, but blocked the curli production, confirming that inactivation of RcsB in C+ variants was the basis of fitness segregation within the EcO157population. This study provides an example of how genome instability of EcO157promotes the intra-population diversification, generating sub-populations carrying an array of distinct phenotypes that may confer the pathogen survival advantages in host and nonhost environments. Three replicates for isolates RM6607R, RM6607W, RM6608R, RM6608W independently grown from single colonies in LB broth and incubated at 28M-BM-0C overnight on a shaker (150 rpm). The cells were collected by centrifugation, washed once in LBNS broth, and inoculated in 25ml of LBNS broth with a concentration equivalent to 0.001OD600 ml-1. The cultures were incubated at 28M-BM-0C for 24 h with aeration (150 rpm). At the end of incubation, ice-cold phenol-ethanol (5%:95%) solution was immediately added to culture at a final concentration of 20% (volume), and the mixture was incubated on ice for 30 min. The cells were collected by centrifugation at 4M-BM-0C and the pellets were stored at -80M-BM-0C until RNA extraction. The cells were collected by centrifugation, washed once in LBNS broth, and inoculated in 25ml of LBNS broth with a concentration equivalent to 0.001OD600 ml-1. The cultures were incubated at 28M-BM-0C for 24 h with aeration (150 rpm). At the end of incubation, ice-cold phenol-ethanol (5%:95%) solution was immediately added to culture at a final concentration of 20% (volume), and the mixture was incubated on ice for 30 min. The cells were collected by centrifugation at 4M-BM-0C and the pellets were stored at -80M-BM-0C until RNA extraction. RNA was isolated using Promega SV Total RNA kit. A type 2 gene expression experimental design was used, with fluorescently labeled genomic DNA as a reference channel in each experiment as described by Lucchini, S., et al. 2005. Infect Immun 73:88-102.
2012-08-31 | E-GEOD-39439 | biostudies-arrayexpress
Project description:Bacillus subtilis encodes seven extracytoplasmic function (ECF) sigma factors. Three (sigma M, sigma W and simga X) mediate responses to cell envelope active antibiotics. The functions of sigma Y, sigma Z, sigma V, and YlaC remain largely unknown, and strong inducers of these sigma factors and their regulons have yet to be defined. Here, we define transcriptomic and phenotypic differences under non-stress conditions between strains carrying deletions in all seven ECF sigma factor genes (Δ7ECF), a sigMWX triple mutant (∆MWX), and the parental 168 strain. Our results identify >80 genes as at least partially dependent on ECF sigma factors and, as expected, most of these are dependent on sigma M, sigma W or sigma X which are active at a significant basal level during growth. Several genes, including the eps operon encoding enzymes for exopolysaccharide (EPS) production, were decreased in expression in Δ7ECF but affected little if at all in ΔMWX. Consistent with this observation, Δ7ECF (but not ∆MWX) showed reduced biofilm formation. Extending previous observations, we also note that ∆MWX is sensitive to a variety of antibiotics and Δ7ECF is either as sensitive as, or slightly more sensitive than, the ΔMWX strain to these stressors. These findings emphasize the overlapping nature of the seven ECF s factor regulons in B. subtilis, confirm that three of these (sigma M, W or X) play the dominant role in conferring intrinsic resistance to antibiotics, and provide initial insights into the roles of the remaining ECF sigma factors. Strains WT vs. ΔMWX, WT vs. Δ7ECF, Δ7ECF vs. ΔMWX. Each experiment was conducted three times using three independent total RNA preparations (biological triplicates). For each paried comparison, one sample was was labeled with Alexa Fluor 555 and the other was with Alexa Fluor 647. For each comparison, one replicate was performed with dyewap with the same RNA preparation.
2010-07-21 | E-GEOD-22930 | biostudies-arrayexpress
Project description:Bacillus subtilis encodes seven extracytoplasmic function (ECF) sigma factors. Three (sigma M, sigma W and simga X) mediate responses to cell envelope active antibiotics. The functions of sigma Y, sigma Z, sigma V, and YlaC remain largely unknown, and strong inducers of these sigma factors and their regulons have yet to be defined. Here, we define transcriptomic and phenotypic differences under non-stress conditions between strains carrying deletions in all seven ECF sigma factor genes (Δ7ECF), a sigMWX triple mutant (∆MWX), and the parental 168 strain. Our results identify >80 genes as at least partially dependent on ECF sigma factors and, as expected, most of these are dependent on sigma M, sigma W or sigma X which are active at a significant basal level during growth. Several genes, including the eps operon encoding enzymes for exopolysaccharide (EPS) production, were decreased in expression in Δ7ECF but affected little if at all in ΔMWX. Consistent with this observation, Δ7ECF (but not ∆MWX) showed reduced biofilm formation. Extending previous observations, we also note that ∆MWX is sensitive to a variety of antibiotics and Δ7ECF is either as sensitive as, or slightly more sensitive than, the ΔMWX strain to these stressors. These findings emphasize the overlapping nature of the seven ECF s factor regulons in B. subtilis, confirm that three of these (sigma M, W or X) play the dominant role in conferring intrinsic resistance to antibiotics, and provide initial insights into the roles of the remaining ECF sigma factors.
2010-07-21 | GSE22930 | GEO
Project description:Cell-surface signaling is a sophisticated regulatory mechanism used by gram-negative bacteria to sense signals from outside the cell and transmit them into the cytoplasm. This regulatory system consists of an outer membrane-localized TonB-dependent receptor (TonB-dependent transducer), a cytoplasmic membrane-localized anti-sigma factor and an extracytoplasmic function (ECF) sigma factor. By microarray analysis we have identified the regulons of four novel P. aeruginosa signaling systems. For that, the ECF sigmas PA0149, PA2050, PA2093 and PA4896 have been overexpressed in P. aeruginosa and their target gene candidates have been identified using DNA microarray. Keywords: Overexpression of ECF sigma factors
2007-11-24 | GSE9657 | GEO
Project description:Background. The bacterial foodborne pathogen Campylobacter jejuni is a common cause of acute gastroenteritis and is also associated with the postinfectious neuropathies, Guillain-Barré and Miller Fisher syndromes. This study described the use of multilocus sequence typing and DNA microarrays to examine the genetic content of a collection of South African C. jejuni strains, recovered from patients with enteritis, Guillain-Barré or Miller Fisher syndromes. Methodology/Principal Findings. The comparative genomic analysis by using multilocus sequence typing and DNA microarrays demonstrated that the South African strains with Penner heat-stable (HS) serotype HS:41 were clearly distinct from the other South African strains. Further analysis of the DNA microarray data demonstrated that the serotype HS:41 strains from South African GBS and enteritis patients are highly similar in gene content. Interestingly, the South African HS:41 strains were distinct in gene content when compared to serotype HS:41 strains from other geographical locations due to the presence of genomic islands, referred to as Campylobacter jejuni integrated elements. Only the genomic integrated element CJIE1, a Campylobacter Mu-like prophage, was present in the South African HS:41 strains whereas absent in the closely-related HS:41 strains from Mexico. A more distantly-related HS:41 strain from Canada possessed both genomic integrated elements CJIE1 and CJIE2. Conclusion/Significance. These findings demonstrated that these C. jejuni integrated elements may contribute to the differentiation of closely-related C. jejuni strains. In addition, the presence of bacteriophage-related genes in CJIE1 may probably contribute to increasing the genomic diversity of these C. jejuni strains. This comparative genomic analysis of the foodborne pathogen C. jejuni provides fundamental information that potentially could lead to improved methods for analyzing the epidemiology of disease outbreaks and their sources. The genomic diversity of 33 South African, 2 Mexican and 1 Canadian Campylobacter jejuni strains from humans were examined by microarray-based comparative genomic indexing (CGI) analysis. The CGI analysis allowed the assessment of CDS content for each C. jejuni strain relative to the C. jejuni DNA microarray, which comprises ORFs from strains NCTC 11168, RM1221. ORFs were spotted in duplicate. Genomic DNA from strains NCTC 11168/RM1221 were used as a reference DNA and competitively hybridized with genomic DNA from each of the other C. jejuni strains. Two or three replicates for each strain were performed. Data normalization was performed as in Parker et al. J Clin Microbiol 2006, 44(11):4125-4135.
2010-05-27 | E-GEOD-9862 | biostudies-arrayexpress
Project description:The species Campylobacter jejuni is naturally competent for DNA uptake; nevertheless, nonnaturally transformable strains do exist. For a subset of strains we previously showed that a periplasmic DNase, encoded by dns, inhibits natural transformation in C. jejuni. In the present study, genetic factors coding for DNase activity in absence of dns were identified. DNA arrays indicated that nonnaturally transformable dns-negative strains contain putative DNA/RNA non-specific endonucleases encoded by CJE0566 and CJE1441 of strain RM1221. These genes are located on C. jejuni integrated element 2 and 4. Expression of CJE0566 and CJE1441 from strain RM1221 and a homologous gene from strain 07479 in DNase-negative Escherichia coli and C. jejuni strains indicated that these genes code for DNases. Genetic transfer of the genes to a naturally transformable C. jejuni strain resulted in a decreased efficiency of natural transformation. Modelling suggests that the C. jejuni DNases belong to the Serratia nuclease family. Overall, the data indicate that the acquisition of prophage encoded DNA/RNA non-specific endonucleases inhibits the natural transformability of C. jejuni through hydrolysis of DNA. The genomic diversity of 15 naturally competent or nonnaturally transformable Campylobacter jejuni strains were examined by microarray-based comparative genomic indexing (CGI) analysis. The CGI analysis allowed the assessment of CDS content for each C. jejuni strain relative to the C. jejuni DNA microarray, which comprises ORFs from strains NCTC 11168, RM1221. ORFs were spotted in duplicate. Genomic DNA from strains NCTC 11168/RM1221 were used as a reference DNA and competitively hybridized with genomic DNA from each of the other C. jejuni strains. Two replicates for each strain were performed. Data normalization was performed as in Parker et al. J Clin Microbiol 2006, 44(11):4125-4135.
2009-11-13 | E-GEOD-18399 | biostudies-arrayexpress
Project description:C. jejuni, a spiral-shaped gram-negative bacterium, is a leading bacterial cause of human foodborne illness. Acute disease is associated with C. jejuni invasion of the intestinal epithelium. Further, maximal host cell invasion requires the secretion of proteins termed Campylobacter invasion antigens (Cia). As bile acids are known to alter the pathogenic behavior of other gastrointestinal pathogens, we hypothesized that the virulence potential of Campylobacter may be triggered by the bile acid deoxycholate (DOC). In support of this hypothesis, culturing C. jejuni with a physiologically relevant concentration of DOC significantly altered the kinetics of cell invasion as evidenced by gentamicin-protection assays. In contrast to C. jejuni harvested from Mueller-Hinton (MH) agar plates, C. jejuni harvested from MH agar plates supplemented with DOC demonstrated Cia secretion as judged by metabolic labeling experiments. DOC was also found to induce the expression of the ciaB gene as judged by B-galactosidase reporter assays and real-time RT-PCR. Microarray analysis revealed that DOC induced the expression of virulence genes (i.e., ciaB, cmeABC, dccR, and tlyA). In summary, we demonstrate that it is possible to enhance the pathogenic behavior of C. jejuni by modifying the culture conditions. These results provide a foundation to identify genes expressed by C. jejuni in response to in vivo-like culture conditions. Keywords: Stress response For the expression profiling arrays, an indirect comparison of gene expression was performed, where the expression profile of the C. jejuni F38011 cultured in the presence and absence of DOC was measured separately on different slides as described previously (26). Briefly, Cy5 labeled reference DNA from the C. jejuni F38011 strain was mixed with Cy3 labeled test cDNA (C. jejuni F38011 cultured in the presence or absence of DOC) and hybridized to the Campylobacter cDNA array (26) on separate slides. DNA microarrays were scanned using an Axon GenePix 4000B microarray laser scanner (Axon Instruments, Union City, CA) and the data for spot and background intensities were processed using the GenePix 4.0 software. To compensate for any effect of the amount of template and uneven Cy-dye incorporation, data normalization was performed as previously described (26). For the comparison of genes differentially expressed in the presence and absence of DOC,six hybridization measurements were generated per biological experiment (three technical replicate arrays and two replicate features per array).
2010-05-26 | E-GEOD-10110 | biostudies-arrayexpress