Project description:A global differential transcriptomic profiling of Mycobacterium gilvum PYR-GCK during pyrene and glucose metabolism, using RNA seq.
Project description:A functional microarray targeting 24 genes involved in chlorinated solvent biodegradation pathways has been developed and used to monitor the gene expression in a contaminated site (site B) under ERD (enhanced reductive dechlorination) treatment. The microarray format provided by NimbleGen and used in this study is 12x135K. 4 M-BM-5g of labelled antisense mRNA from 3 groundwater samples were hybridized on the microarray. A 3-chip study was performed, each corresponding to hybridization with 4 M-BM-5g of labelled antisense mRNA retrieved from a monitoring well of a contaminated site (site B). Each probe (760nt) on the microarray was synthesized in eight replicates, and a total of 5,707 random probes was used to determine the background noise. Groundwater samples were collected from a contaminated site (site B) from three monitoring wells (P1, P2 and P3). P1: well located upstream to the contamination source. P2: well in the contamination source. P3 : well located downstream to the contamination source.
Project description:We analyzed the transcriptional response of the actinomycete Rhodococcus aetherivorans I24 to biphenyl and polychlorinated biphenyls (PCBs). This species has not been extensively exposed to PCBs, as it was first isolated from a toluene contaminated aquifer, rather than a site contaminated with polychlorinated hydrocarbons. Using a microarray targeting 3524 genes, we assessed gene expression in minimal medium supplemented with various substrates (e.g. PCBs) and in both PCB-contaminated and non-contaminated sediment slurries. Relative to the reference condition (minimal medium supplemented with glucose), 408 genes were up-regulated in the various treatments. In medium and in sediment, PCBs elicited the up-regulation of a common set of 100 genes, including chaperones (groEL), a superoxide dismutase (sodA), alkyl hydroperoxide reductase protein C (ahpC), and a catalase/peroxidase (katG). Analysis of the R. aetherivorans I24 genome sequence identified orthologs of many of the genes in the canonical biphenyl pathway, but very few of these genes were up-regulated in response to PCBs or biphenyl. This study is one of the first which utilizes microarrays to assess the transcriptional response of a soil bacterium to a pollutant under conditions which more closely resemble the natural environment. Our results indicate that the transcriptional response of R. aetherivorans I24 to PCBs, in both medium and sediment, is primarily directed towards reducing oxidative stress, rather than catabolism. In addition, the identification of numerous genes expressed in contaminated soil specifically may have implications for the development of biosensors. Finally, comparative genomic and transcriptomic analyses suggest that the mere presence of orthologs of the required enzymes may not be sufficient to confer a vigorous biphenyl/PCB metabolism. RNA was isolated from cells incubated in the following: sediment from a PCB-contaminated industrial site, uncontaminated sediment from a comparable site, and defined media supplemented with glucose (3 g/L), glucose and biphenyl (3 g/L, 4.5 μM), or glucose and PCBs (3 g/L, 5 mg/L Aroclor 1254). In all cases, there were 3 biological replicates and 2 technical replicates (repeat hybridizations). A total of 3524 genes are represented on the arrays; of these, 41 and 176 are found on the plasmids pRA2 and pRA3, respectively. On average, there are 3 distinct 24nt probes per gene.
Project description:Herbivores are predicted to evolve appropriate mechanisms to process the plant secondary compounds (PSCs) in their diet and these mechanisms are likely specific to particular suites of PSCs. Changes in diet composition over evolutionary time should select for appropriate alterations in metabolism of the more recent dietary components. We investigated differences in gene expression profiles in the liver with respect to prior ecological and evolutionary experience with PSCs in the desert woodrat, Neotoma lepida. This woodrat species has populations in the Mojave Desert that have switched from feeding on juniper to feeding on creosote at the end of the Holocene as well as populations in the Great Basin Desert that still feed on the ancestral diet of juniper and are naïve to creosote. Juniper and creosote have notable differences in secondary chemistry. Woodrats from the Mojave and Great Basin Deserts were subjected to a fully crossed feeding trial on diets of juniper and creosote after which their livers were analyzed for gene expression. Hybridization of hepatic mRNAs to laboratory rat microarrays resulted in a total of 20,031 genes that met quality control standards. We analyzed differences in large-scale patterns of liver gene expression with respect to GO term enrichment. Diet had a larger effect on gene expression than population membership. However, woodrats with no prior evolutionary experience to the diet upregulated relatively far more genes compared to animals with prior exposure to that diet. This pattern may be the result of naive animal’s attempting to mitigate physiological damage caused by novel PSCs. fully crossed design, two by two feeding trial with two populations of the desert woodrat (Great Basin and Mojave) fed the two diets of juniper and creosote bush
Project description:This SuperSeries is composed of the following subset Series: GSE28606: Monitoring of functional gene responses to ERD (enhanced reductive dechlorination) from four TCE-contaminated sites GSE28608: Monitoring of functional gene responses to biostimulation from a TCE-contaminated site Refer to individual Series