Project description:The alkaliphilic halotolerant bacterium Bacillus sp. N16-5 often faces salt stress in its natural habitats. One-color microarrays was used to investigate transcriptome expression profiles of Bacillus sp. N16-5 adaptation reactions to prolonged grown at different salinities (0%, 2%, 8% and 15% NaCl) and the initial reaction to suddenly alter salinity from 0% to 8% NaCl.
Project description:In Xenopus, establishment of the anterior-posterior axis involves two key signalling pathways, canonical Wnt and Nodal-related TGF-β. There are also a number of transcription factors that feedback upon these pathways. The homeodomain protein Hex, an early marker of anterior positional information, acts as a transcriptional repressor suppressing induction and propagation of the Spemman organiser while specifying anterior identity. We show that Hex promotes anterior identity by amplifying the activity of canonical Wnt signalling. Hex exerts this activity by inhibiting the expression of Tle-4, a member of the Groucho family of transcriptional co-repressors that we identified as a Hex target in embryonic stem (ES) cells and Xenopus embryos. This Hex-mediated enhancement of Wnt signalling results in the up-regulation of the Nieuwkoop centre genes Siamois and Xnr-3 and the subsequent increased expression of the anterior endodermal marker Cerberus and other mesendodermal genes downstream of Wnt signalling. We also identified Nodal as a Hex target in ES cells. We demonstrate that in Xenopus, the Nodal-related genes Xnr-1 and 2, but not 5 and 6, are regulated directly by Hex. The identification of Nodal-related genes as Hex targets explains the ability of Hex to suppress induction and propagation of the organiser. Together these results support a model in which Hex acts early in development to reinforce a Wnt-mediated, Nieuwkoop-like signal to induce anterior endoderm, and later in this tissue to block further propagation of Nodal-related signals. The ability of Hex to regulate the same targets in both Xenopus and mouse implies this model is conserved. Keywords: genetic modification
Project description:The alkaliphilic halotolerant bacterium Bacillus sp. N16-5 often faces salt stress in its natural habitats. One-color microarrays was used to investigate transcriptome expression profiles of Bacillus sp. N16-5 adaptation reactions to prolonged grown at different salinities (0%, 2%, 8% and 15% NaCl) and the initial reaction to suddenly alter salinity from 0% to 8% NaCl. Salt induced gene expression was measured when culture was grown on different salinities (0%, 2%, 8% and 15% NaCl) to mid-logarithmic phase. And salt induced gene expression was also measured at 0 min, 10 min, 30 min, 60min, 120min after a sudden change salinity from 0% to 8% NaCl.
Project description:Alkaline hemicellulytic bacteria Bacillus sp. N16-5 has abroad substrate spectrum and exhibits great growth ability on complex carbohydrates. In order to get insight into its carbohydrate utilization mechanism, global transcriptional profiles were separately determined for growth on glucose, fructose, mannose, galactose, arabinose, xylose, galactomannan, xylan, pectin and carboxymethyl cellulose by using one-color microarrays.
