Project description:Four stable and robust TCE-dechlorinating microbial communities were enriched from TCE-contaminated groundwater under four different conditions exploring two parameters, high and low methanogenic activity (Meth and NoMeth), with and without vitamin B12 supplement (MethB12 and NoMethB12, Meth and NoMeth, respectively). Identical amounts of lactate (2.7 mmol) and TCE (20 M-NM-<l) were supplied as electron donor and electron acceptor. All four cultures were capable of reductively dechlorinating TCE to VC and ethene. Genomic DNA of the four enrichments was applied on a quad-Dhc-genome microarray in order to characterize the gene content of Dehalococcoides species present in the four enrichments The genomic DNA of four enrichment cultures completely dechlorinated TCE to VC and ethene was used on the microarray to query Dehalococcoides species present in the mixed cultures.
Project description:The aim of this study is to obtain a systems level understanding of the interactions between Dehalococcoides and corrinoid-supplying microorganisms by analyzing community structures and functional compositions, activities and dynamics in trichloroethene (TCE)-dechlorinating enrichments. Metagenomes and metatranscriptomes of the dechlorinating enrichments with and without exogenous cobalamin were compared. Seven draft genomes were binned from the metagenomes. At an early stage (2 d), more transcripts of genes in the Veillonellaceae bin-genome were detected in the metatranscriptome of the enrichment with exogenous cobalamin compared to the one without cobalamin addition. Among these genes, sporulation-related genes exhibited the highest differential expression when cobalamin was not added, suggesting a possible release route of corrinoids from corrinoid-producers. Other differentially expressed genes include those involved in energy conservation and nutrient transport (including cobalt transport). The most highly expressed corrinoid de novo biosynthesis pathway was also assigned to the Veillonellaceae bin-genome. Targeted qPCR analyses confirmed higher transcript abundances of those corrinoid biosynthesis genes in the enrichment without exogenous cobalamin. Furthermore, Dehalococcoides' corrinoid salvaging and modification pathway was upregulated in response to the cobalamin stress. This study provides important insights into the microbial interactions and roles of members of dechlorinating communities under cobalamin-limited conditions.
Project description:Four stable and robust TCE-dechlorinating microbial communities were enriched from TCE-contaminated groundwater under four different conditions exploring two parameters, high and low methanogenic activity (Meth and NoMeth), with and without vitamin B12 supplement (MethB12 and NoMethB12, Meth and NoMeth, respectively). Identical amounts of lactate (2.7 mmol) and TCE (20 μl) were supplied as electron donor and electron acceptor. All four cultures were capable of reductively dechlorinating TCE to VC and ethene. Genomic DNA of the four enrichments was applied on a quad-Dhc-genome microarray in order to characterize the gene content of Dehalococcoides species present in the four enrichments
Project description:The Ag receptors on alpha/beta and gamma/delta T cells differ not only in the nature of the ligands that they recognize but also in their signaling potential. We hypothesized that the differences in alpha/beta - and gamma/delta TCR signal transduction were due to differences in the intracellular signaling pathways coupled to these two TCRs. To investigate this, we employed transcriptional profiling to identify genes encoding signaling molecules that are differentially expressed in mature alpha/beta and gamma/delta T cell populations. Unexpectedly, we found that B lymphoid kinase (Blk), a Src family kinase expressed primarily in B cells, is expressed in gamma/delta T cells but not in alpha/beta T cells. Analysis of Blk-deficient mice revealed that Blk is required for the development of IL-17-producing gamma/delta T cells. Furthermore, Blk is expressed in lymphoid precursors and, in this capacity, plays a role in regulating thymus cellularity during ontogeny. Naive alpha/beta and gamma/delta T cells isolated from mouse lymph nodes and purified by negative selection were compared using MOE430 2.0 GeneChip.