Comparative transcriptomics in Yersinia pestis: a global view of environmental modulation of gene expression

<p>Abstract</p> <p>Background</p> <p>Environmental modulation of gene expression in <it>Yersinia pestis </it>is critical for its life style and pathogenesis. Using cDNA microarray technology, we have analyzed the global gene expression of this deadly pathogen when grown under different stress conditions <it>in vitro</it>.</p> <p>Results</p> <p>To provide us with a comprehensive view of environmental modulation of global gene expression in <it>Y. pestis</it>, we have analyzed the gene expression profiles of 25 different stress conditions. Almost all known virulence genes of <it>Y. pestis </it>were differentially regulated under multiple environmental perturbations. Clustering enabled us to functionally classify co-expressed genes, including some uncharacterized genes. Collections of operons were predicted from the microarray data, and some of these were confirmed by reverse-transcription polymerase chain reaction (RT-PCR). Several regulatory DNA motifs, probably recognized by the regulatory protein Fur, PurR, or Fnr, were predicted from the clustered genes, and a Fur binding site in the corresponding promoter regions was verified by electrophoretic mobility shift assay (EMSA).</p> <p>Conclusion</p> <p>The comparative transcriptomics analysis we present here not only benefits our understanding of the molecular determinants of pathogenesis and cellular regulatory circuits in <it>Y. pestis</it>, it also serves as a basis for integrating increasing volumes of microarray data using existing methods.</p

Expression of the Type VI Secretion System 1 Component Hcp1 Is Indirectly Repressed by OpaR in Vibrio parahaemolyticus

The type VI secretion system (T6SS) is bacterial protein injection machinery with roles in virulence, symbiosis, interbacterial interaction, antipathogenesis, and environmental stress responses. There are two T6SS loci, T6SS1 and T6SS2, in the two chromosomes of Vibrio parahaemolyticus, respectively. This work disclosed that the master quorum sensing (QS) regulator OpaR repressed the transcription of hcp1 encoding the structural component Hcp1 of T6SS1 in V. parahaemolyticus, indicating that QS had a negative regulatory action on T6SS1. A single σ54-dependent promoter was transcribed for hcp1 in V. parahaemolyticus, and its activity was repressed by the OpaR regulator. Since the OpaR protein could not bind to the upstream region of hcp1, OpaR would repress the transcription of hcp1 in an indirect manner

Comparative transcriptomics in : a global view of environmental modulation of gene expression-4

<p><b>Copyright information:</b></p><p>Taken from "Comparative transcriptomics in : a global view of environmental modulation of gene expression"</p><p>http://www.biomedcentral.com/1471-2180/7/96</p><p>BMC Microbiology 2007;7():96-96.</p><p>Published online 29 Oct 2007</p><p>PMCID:PMC2231364.</p><p></p>7 contain 1.0, 0.7, 0.4, 0.1 and 0 μg of the recombinant Fur protein. In (A) – (I), an arrow and an asterisk indicate the probe (free) and the Fur-probe complex (bound), respectively

Involvement of gut-brain communication in arsenite-induced neurobehavioral impairments in adult male mice

Arsenite is a well-documented neurotoxic metalloid that widely distributes in the natural environment. However, it remains largely unclear how arsenite affects neurological function. Therefore, in this study, the healthy adult male mice were exposed to 0.5 mg/L and 5 mg/L arsenite through drinking water for 30 and 90 days, respectively. Our results showed that there was no significant alteration in the intestine and brain for 30 days exposure, but exposure to arsenite for 90 days significantly induced a reduction of locomotor activity and anxiety-like behavior, caused pathological damage and inflammatory responses in the brain and intestine. We also found that arsenite remarkably disrupted intestinal barrier integrity, decreased the levels of lysozyme and digestive enzymes. Intriguingly, chronic exposure to arsenite significantly changed the levels of gut-brain peptides. Taken together, this study provides meaningful insights that gut-brain communication may involve in the neurobehavioral impairments of arsenite

Comparative transcriptomics in : a global view of environmental modulation of gene expression-2

<p><b>Copyright information:</b></p><p>Taken from "Comparative transcriptomics in : a global view of environmental modulation of gene expression"</p><p>http://www.biomedcentral.com/1471-2180/7/96</p><p>BMC Microbiology 2007;7():96-96.</p><p>Published online 29 Oct 2007</p><p>PMCID:PMC2231364.</p><p></p>n in Table 4, while rows from up to down represent genes and their corresponding gene names were listed in the order (left to right and up to down). The black vertical lines are used to define the range of clusters of co-expressed genes. Red represents up-regulation and green represents down-regulation of the corresponding genes

Comparative transcriptomics in : a global view of environmental modulation of gene expression-3

<p><b>Copyright information:</b></p><p>Taken from "Comparative transcriptomics in : a global view of environmental modulation of gene expression"</p><p>http://www.biomedcentral.com/1471-2180/7/96</p><p>BMC Microbiology 2007;7():96-96.</p><p>Published online 29 Oct 2007</p><p>PMCID:PMC2231364.</p><p></p>R-like box; and (c) Fnr-like box. The underlined number is the maximum possible score with PSSM. For the sequence logo, the height of each letter indicates the relative frequency of that base at that position, while the height of each stack of letters corresponds to the sequence conservation at that position