Project description:Here, we applied a microarray-based metagenomics technology termed GeoChip 5.0 to investigate spring microbial functional genes in mesocosm-simulated shallow lake ecosystems having been undergoing nutrient enrichment and warming for nine years.
Project description:Epigenetic variation has the potential to control environmentally dependent development and contribute to phenotypic responses to local environments. Environmental epigenetic studies of sexual organisms confirm the responsiveness of epigenetic variation, which should be even more important when genetic variation is lacking. A previous study of an asexual snail, Potamopyrgus antipodarum, demonstrated that different populations derived from a single clonal lineage differed in both shell phenotype and methylation signature when comparing lake versus river populations. Here, we examine methylation variation among lakes that differ in environmental disturbance and pollution histories. The differential DNA methylation regions (DMRs) identified among the different lake comparisons suggested a higher number of DMRs and variation between rural Lake 1 and one urban Lake 2 and between the two urban Lakes 2 and 3, but limited variation between the rural Lake 1 and urban Lake 3. DMR genomic characteristics and gene associations were investigated. Observations suggest there is no effect of geographic distance or any consistent pattern of DMRs between urban and rural lakes. Environmental factors may influence epigenetic response.
Project description:To determine gene expression differences in the olfactory epithelium of sea lamprey between sequential yet behaviorally distinct adult life history stages 2 samples: parasitic adults removed from fish in northern Lake Huron and Lake Michigan in February and March, and reproductive adults collected from Lake Huron and Lake Michigan tributaries in June
Project description:Our main objectives wereto investigate the molecular mechanisms involved in metal toxicity and detoxification in the field using juvenile yellow perch subjected to differents levels of this metal exposure. Recent local adaptation to pollution has been evidenced in several organisms inhabiting environments heavily contaminated by metals. Nevertheless, the molecular mechanisms underlying adaptation to high metal concentrations are poorly understood, especially in fishes. Yellow perch (Perca flavescens) populations from lakes in the mining area of Rouyn-Noranda (QC, Canada) have been faced with metal contamination for about 90 years. Here, we examine gene transcription patterns of fish reciprocally transplanted between a reference and a metal-contaminated lake and also fish caged in their native lake. After four weeks, 111 genes were differentially transcribed in metal-naïve fish transferred to the metal-contaminated lake, revealing a plastic response to metal exposure. Genes involved in the citric cycle and beta-oxidation pathways were under-transcribed, suggesting a potential strategy to mitigate the effects of metal stress by reducing energy turnover. However, metal-contaminated fish transplanted to the reference lake did not show any transcriptomic response, indicating a reduced plastic response capability to sudden reduction in metal concentrations. Moreover, the transcription of other genes, especially ones involved in energy metabolism, was affected by caging. Overall, our results highlight environmental stress response mechanisms in yellow perch at the transcriptomic level and support a rapid adaptive response to metal exposure through genetic assimilation. Comparison between fish Op and OpâOp using a pairwise design corresponding to the cage experiment in the reference lake Opasatica (Op), comparison between fish Du and DuâDu using a pairwise design corresponding to the cage experiment in the metal contaminated lake Dufault (Du), comparison between fish from reference lake transplanted to the metal contaminated lake (OpâDu) and fish from reference lake caged in their own lake (OpâOp) using pairwise design corresponding to the experiment of metal contamination, comparison between fish from metal contaminated lake transplanted to the reference lake (DuâOp) and fish from the metal contaminated lake caged in their own lake (DuâDu) using pairwise design corresponding to the depuration experiment.
Project description:In this study, we investigated Mn3+-cycling microbial populations enriched from Lake Matano, Indonesia using metagenomics and metaproteomics. Lake Matano contains an active Mn cycle that links the oxic-anoxic interface with anoxic deep waters that are enriched in iron and manganese, and depleted in sulfate, phosphate, and oxidized nitrogen (Crowe et al., 2008; Jones et al., 2011). Sediments were incubated with sequential transfers for ~1 year with Mn3+ as the sole electron acceptor and methane as organic carbon until achieving sediment-free conditions. Here we investigate this novel species of Dechloromonas (Betaproteobacteria), “Candidatus Dechloromonas occultata,” which was the dominant population in enrichment cultures with active Mn3+ reduction. “Ca. D. occultata” expressed electron conduits related to those involved in Fe2+ oxidation (Mto-like), as well as a novel cytochrome c-rich gene cluster putatively involved in extracellular electron transfer, and an atypical nitrous oxide reductase. According to ribosomal counts, Dechloromonas outnumber Geobacter. In terms of functional genes, Dechloromonas expresses a wider variety and number of genes. Dechloromonas therefore seems to have a (selective?) advantage over Geobacter. Previous experiments revealed that Dechloromonas express nitrogen regulators, reductases and scavenging genes, as well as many carbon central metabolic pathways, and aromatic carbon degradation pathways. Dechloromonas is a beta proteobacteria, and these are "experts" in nitrogen metabolism. Geobacter, on the other hand, is well known for carbon degradation. Our previous experiments lead to our hypothesis that Dechloromonas is more active because they are more successful at acquiring nitrogen, a limiting nutrient for Geobacter. This would further suggest that carbon is not the limiting nutrient. We will test 2 hypotheses with the next suite of experiments 1) pyrophosphate supports the community, by allowing carbon fixation , 2)Dechloromonas has a (selective?) advantage over Geobacter. To test this hypothesis, bioreactors will be used to grow biotriplicate cultures of (1)- CH4 vs. pyrophosphate and (2)-CH4 vs. Mn(III) pyrophosphate. Here we have analyzed whole cell pellets using gas phase fractionations on the Q Exactive. Are Dechloromonas capable of out-competing Geobacter when grown in media with methane as the only carbon source bioreactors because they are capable of acquiring more nitrogen? Source of inoculum. Lake Matano is a metal-rich, ancient ocean analog (Crowe et al. 2011, Jones et al. 2011). Organic carbon in Lake Matano is mostly mineralized via methanogenesis before reaching the iron-rich sediments, limiting organic matter bioavailability for metal-reducers (Kuntz et al. 2015). A 15-cm sediment core from 200 m water depth in Lake Matano, Sulawesi Island, Indonesia (02°26′27.1′′S, 121°15′12.3′′E; in situ sediment temperature ~27°C) was sampled in November 2014 and sub-sampled at 5 cm increments. Sediments were sealed in gas-tight Mylar bags with no headspace (Hansen et al. 2000) and stored at 4°C until incubations began in December 2015.
Project description:NGS2013-04: Transcriptomic response to Nod Factor treatments on Medicago Role of the root hair in water and nutrient uptake and the establishment of the nitrogen-fixing symbiotic interaction with rhizobia.
Project description:We used Arabidopsis thaliana Col-0 for all experiments. The plants were grown hydroponically on nutrient solution as described previously [Plant J 1999, 18(5):509-519]. Briefly, plants were grown on sand, placed in custom-designed styrofoam rafts, in a growth chamber (EGC, Chagrin Falls, OH, USA) at 22°C with 60 mmol photons m-2s-1 light intensity and 8 h/16 h light/dark cycles. The seeds were initially germinated in tap water. After one week, the water was replaced with a complete nutrient solution [Plant J 1999, 18(5):509-519]. All the experiments were performed with 6 week old plants. Nutrient solutions were renewed weekly and on the day before the experiments. For treatments, individual rafts were transferred to containers with 300mL of nutrient solution supplemented with various concentrations of nitrate (as a mix of 2/1 KNO3/Ca(NO3)2) and/or sucrose. The N-free nutrient solutions contained 0.25 mM K2SO4 and 0.25 mM CaCl2 instead of KNO3 and Ca(NO3)2. Plants were transferred to treatments media at the beginning of the light period and were harvested 8h afterwards. Roots and leaves were harvested separately and quickly frozen in liquid N2.
Project description:Transcriptional Regulation in liver and ovary associated with developmental and reproductive effects in female Zebrafish exposed to natural mixtures of persistent organic pollutants from Lake Mjosa or Lake Losna
Project description:Lake trout are used as bioindicators for toxics exposure in the Great Lakes ecosystem. However, there is no knowledge about lake trout proteome. Here we performed the first lake trout (Salvelinus namaycush) liver proteomics and searched the databases against (NCBI and UniProtKB) Salvelinus, Salmonidae, Actinopterygii and the more distant Danio rerio. In the NCBI search, we identified 4371 proteins in 1252 clusters. From these proteins, we found 2175 proteins in Actinopterygii 1253 in Salmonidae, 69 in Salvelinus and 901 in Danio rerio NCBI searches. In the UniProtKB search, we identified 2630 proteins in 1100 clusters. From these proteins, we found 317 in Actinopterygii, 1653 in Salmonidae, 37 in Salvelinus and 666 in Danio rerio UniProtKB searches. A similar outcome was also obtained from a technical replicate experiment. A large number of lake trout liver proteins were not in any Salvelinus databases, suggesting that lake trout liver proteins have homologues to some proteins from the Salmonidae family and Actinopterygii class, as well as to the species Danio rerio, a more highly studied Cypriniformes fish. Therefore, our study not only builds the first comprehensive lake trout protein database, but also establishes protein homology-based evolutionary relationships between the fish within their family and class, as well as distant-related fish (lake trout and zebrafish). In addition, this study opens the possibility of identifying evolutionary relationships (i.e. adaptive mutations) between various groups (i.e. zebrafish, Salmonidae, Salvelinus and lake trout) through evolutionary proteomics