8 research outputs found

    Isolation, characterization, and genome sequence of the first representative of a novel class within the Chloroflexi that is abundant in some U.S. Great Basin hot springs and may play important roles in N and C cycling

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    A thermophilic, facultatively microaerophilic, heterotrophic bacterium, designated strain JAD2, was isolated from sediments of Great Boiling Spring (GBS), an ~80oC, circumneutral hot spring in the Great Basin GB). The strain grew anaerobically on yeast extract or peptone with an optimal growth temperature of 70-75oC. Growth was stimulated by addition of 0.01 atm O2 to the culture vessel headspace, but was inhibited by higher concentrations (0.2 atm). Cells of JAD2 formed non-motile filaments ranging from 10 to \u3e300 μm in length, which typically decreased in length during stationary phase. 16S rRNA gene-targeted pyrotag sequencing and clone library data suggest that close relatives of this isolate are prominent members of the sediment communities in GBS. Shotgun sequencing of the JAD2 genome produced an assembly consisting of ~3.2 Mbp with an average G+C content of 67.3%. Phylogenies inferred from the 16S rRNA gene and predicted amino acid sequences of various conserved proteins indicate that JAD2 is the first cultivated representative of the GAL35 group, a new class within the Chloroflexi. Predicted genes in the draft genome encoding a putative carbon monoxide dehydrogenase (coxMSL), nitrite reductase (nrfHA) and nitrous oxide reductase (nosZ) suggest that this isolate may play important roles in N and C cycling in GBS sediments

    CRHR2/Ucn2 signaling is a novel regulator of miR‐7/YY1/Fas circuitry contributing to reversal of colorectal cancer cell resistance to Fas‐mediated apoptosis

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    Colorectal cancer (CRC) responds poorly to immuno-mediated cytotoxicity. Underexpression of corticotropin-releasing-hormone-receptor-2 (CRHR2) in CRC, promotes tumor survival, growth and Epithelial to Mesenchymal Transition (EMT), in vitro and in vivo. We explored the role of CRHR2 downregulation in CRC cell resistance to Fas/FasL-mediated apoptosis and the underlying molecular mechanism. CRC cell sensitivity to CH11-induced apoptosis was compared between Urocortin-2 (Ucn2)-stimulated parental and CRHR2-overexpressing CRC cell lines and targets of CRHR2/Ucn2 signaling were identified through in vitro and ex vivo analyses. Induced CRHR2/Ucn2 signaling in SW620 and DLD1 cells increased specifically their sensitivity to CH11-mediated apoptosis, via Fas mRNA and protein upregulation. CRC compared to control tissues had reduced Fas expression that was associated with lost CRHR2 mRNA, poor tumor differentiation and high risk for distant metastasis. YY1 silencing increased Fas promoter activity in SW620 and re-sensitized them to CH11-apoptosis, thus suggesting YY1 as a putative transcriptional repressor of Fas in CRC. An inverse correlation between Fas and YY1 expression was confirmed in CRC tissue arrays, while elevated YY1 mRNA was clinically relevant with advanced CRC grade and higher risk for distant metastasis. CRHR2/Ucn2 signaling downregulated specifically YY1 expression through miR-7 elevation, while miR-7 modulation in miR-7high SW620-CRHR2+ and miR-7low HCT116 cells, had opposite effects on YY1 and Fas expressions and cell sensitivity to CH11-killing. CRHR2/Ucn2 signaling is a negative regulator of CRC cell resistance to Fas/FasL-apoptosis via targeting the miR-7/YY1/Fas circuitry. CRHR2 restoration might prove effective in managing CRC response to immune-mediated apoptotic stimuli
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