Project description:The experiment compared flounder from the North Sea and the Baltic sea and their reactions on being exposed to water of different salinities
Project description:In the North Sea and adjacent North Atlantic coastal areas fish experience relatively high levels of persistent organic pollutants. The aim of this study is to compare the mode of actions of environmentally relevant concentrations of halogenated compounds and their mixtures in Atlantic cod. Juvenile male cod were fed mixtures of chlorinated (PCBs, DDT analogs, chlordane, lindane and toxaphene), brominated (PBDEs) and fluorinated (Perfluorooctanesulfonate/PFOS) compounds for one month. One group received a mixture of all three compounds. Transcriptome analysis of liver samples was performed to identify the main affected pathways. Accumulated levels of chemicals in cod liver reflected concentrations found in wild fish. Pathway analysis revealed that the treatment effects by each of the three groups of chemicals (chlorinated, brominated and fluorinated) converged on activation of the unfolded protein response (UPR). The results of our transcriptomics analysis suggest that the UPR pathway is a sensitive common target of halogenated organic environmental pollutants
Project description:The available energy and carbon sources for prokaryotes in the deep ocean remain still largely enigmatic. Reduced sulfur compounds, such as thiosulfate, are a potential energy source for both auto- and heterotrophic marine prokaryotes. Shipboard experiments performed in the North Atlantic using Labrador Sea Water (~2000 m depth) amended with thiosulfate led to an enhanced prokaryotic dissolved inorganic carbon (DIC) fixation.
Project description:Beginning in 2013, sea stars throughout the Eastern North Pacific were decimated by wasting disease, also known as ‘asteroid idiopathic wasting syndrome’ (AIWS) due to its elusive etiology. The geographic extent and taxonomic scale of AIWS meant events leading up to the outbreak were heterogeneous, multifaceted, and oftentimes unobserved; progression from morbidity to death was rapid, leaving few tell-tale symptoms. Here we take a forensic genomic approach to discover candidate genes that may help explain sea star wasting syndrome. We report the first genome and annotation for P. ochraceus, along with differential gene expression (DGE) analyses in four size classes, three tissue types, and in symptomatic and asymptomatic individuals. We integrate nucleotide polymorphisms associated with survivors of the wasting disease outbreak, DGE associated with temperature treatments in P. ochraceus, and DGE associated with wasting in another asteroid Pycnopodia helianthoides. In P. ochraceus, we find DGE across all tissues, among size classes, and between asymptomatic and symptomatic individuals; the strongest wasting-associated DGE signal is in pyloric caecum. We also find previously identified outlier loci co-occur with differentially expressed genes. In cross-species comparisons of symptomatic and asymptomatic individuals, consistent responses distinguish genes associated with invertebrate innate immunity and chemical defense, consistent with context-dependent stress responses, defensive apoptosis, and tissue degradation. Our analyses thus highlight genomic constituents that may link suspected environmental drivers (elevated temperature) with intrinsic differences among individuals (age/size, alleles associated with susceptibility) that elicit organismal responses (e.g. coelomocyte proliferation) and manifest as sea star wasting mass mortality.
Project description:Marine microalgae (phytoplankton) mediate almost half of the worldwide photosynthetic carbon dioxide fixation and therefore play a pivotal role in global carbon cycling, most prominently during massive phytoplankton blooms. Phytoplankton biomass consists of considerable proportions of polysaccharides, substantial parts of which are rapidly remineralized by heterotrophic bacteria. We analyzed the diversity, activity and functional potential of such polysaccharide-degrading bacteria in different size fractions during a diverse spring phytoplankton bloom at Helgoland Roads (southern North Sea) at high temporal resolution using microscopic, physicochemical, biodiversity, metagenome and metaproteome analyses.
Project description:Environmental perturbations impact gene transcription. A subset of these transcriptional changes can be passed on to the next generation even in the absence of the initial stimulus. This phenomenon is known as transgenerational inheritance of environmental exposures (TIEE). Previous studies have mainly focused on what is transferred through the germ-line, i.e. DNA methylation, histone modifications, non-coding RNAs, etc. Nevertheless, the germ cells are not the only cells that are passed on from one generation to the next. The microbiota is also transmitted together with the host cells. In this study, we investigated the role of the gut microbiome in TIEE using Drosophila melanogaster as a model organism. We have reared flies in cold and control temperatures, 18 and 25 °C respectively, and looked at the transcriptional pattern in their offspring -grown in control condition- using RNA sequencing. To study the effect of the microbiome, we have carefully exchanged the parental feces introduced to the offspring. We observed genes responsive to thermal alteration, which have preserved their transcriptional status transgenerationally. A subset of these genes, mainly genes expressed in gut, were transcriptionally dependent on which microbiome they acquired. These findings show that the microbiota plays a previously unknown role in TIEE. Our study unveiled a new route for transmittance of environmental memories and thus represents an uncharted area to explore for researchers addressing non-genetic transgenerational inheritance.
Project description:Genome-wide patterns of DNA methylation were quantified using the Illumina Infinium EPIC array (“EPIC array”) in DNA samples isolated from buccal swabs collected at ages 5, 10 and 18 and whole blood samples collected at age 18 from 118 Monozygotic twin pairs from the Environmental Risk (E-Risk) Longitudinal Twin Study. Comparison of DNA methylation profiles of 233 age 18 blood samples with data on EPIC and Illumina 450K methylation arrays.