Project description:Inherited mitochondrial DNA (mtDNA) diseases transmit maternally and cause severe phenotypes. Since no effective treatment or genetic screening is available, nuclear genome transfer between patients’ and healthy eggs to replace mutant mtDNAs holds promises. Since polar body contains very few mitochondria and share same genomic material as oocyte, here we perform polar body transfer to prevent the transmission of inherited mtDNA variants. We compare the value of different germline genome transfer (spindle-chromosome, pronuclear, first and second polar body) in a mouse model. Reconstructed embryos support normal fertilization and produce live offspring. Strikingly, genetic analysis confirms F1 generation after polar body transfer possesses minimal donor mtDNA carry-over compared with spindle-chromosome (low/medium carry-over) and pronuclear (medium/high carry-over) transfer. Moreover, mtDNA genotype remains stable in F2 generation of progeny after polar body transfer. Our preclinical model demonstrates polar body transfer holds great potential in preventing the transmission of inherited mtDNA diseases.
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:Our paper presents the results of a study in which we used whole genome bisulfite sequencing (WGBS) and RNA-Seq (i.e. transcriptomics) to examine the long-term epigenomic dynamics of an experimenta evolution study under high CO2 in the marine cyanobacterium Trichodesmium. We identify m5C methylated sites that rapidly change in response to short-term high CO2 exposure, which are then maintained for 4.5 years even after adaptation (i.e. trait canalization). After 7 years of CO2 selection, high-CO2 triggered methylation levels return to ancestral, low-CO2 levels, consistent with genetic assimilation theory and observations in eukaryotic model systems. These data suggest a potential role for m5C methylation in prokaryotic trait canalization and identify genetic assimilation as an evolutionary mechanism of potential biogeochemical importance under global change factors.
Project description:Our paper presents the results of a study in which we used whole genome bisulfite sequencing (WGBS) and RNA-Seq (i.e. transcriptomics) to examine the long-term epigenomic dynamics of an experimenta evolution study under high CO2 in the marine cyanobacterium Trichodesmium. We identify m5C methylated sites that rapidly change in response to short-term high CO2 exposure, which are then maintained for 4.5 years even after adaptation (i.e. trait canalization). After 7 years of CO2 selection, high-CO2 triggered methylation levels return to ancestral, low-CO2 levels, consistent with genetic assimilation theory and observations in eukaryotic model systems. These data suggest a potential role for m5C methylation in prokaryotic trait canalization and identify genetic assimilation as an evolutionary mechanism of potential biogeochemical importance under global change factors.
Project description:Polar cod, a key fish species in the arctic marine foodweb is vulnerable to effects of pollution from offshore petroleum related activities in the Arctic and sub-arctic region. The study was conducted to map transcriptome responses to in Polar cod (Boreogadus saida) liver slice culture exposed to benzo[a]pyrene (BaP) in the presence or absence of physiological levels of ethynylestradiol (EE2). BaP is a polycyclic aromatic hydrocarbon (PAH), also found in crude oil contaminants. PAHs such as BaP are among the most toxic compounds of crude oil. Precision-cut liver slice cultures from five female polar cod (n = 5/ group, paired design) were exposed to BaP alone (10 µM), or in combination with low concentrations of EE2 (5 nM), to mimic physiological estradiol levels in early vitellogenic female fish. Transcriptome analysis (RNA-seq) was performed after 72 h exposure in culture. The results provide a global view of transcriptome responses to BaP, EE2 and their mixture. In the mixture exposure, BaP resulted attenuation of EE2 stimulated gene expression (anti-estrogenic effects). The results from this ex vivo experiment suggest that pollutants that activate the Ahr pathway such as the PAH compound BaP can result in anti-estrogenic effects that may lead to endocrine disruption in polar cod.
Project description:Inherited mitochondrial DNA (mtDNA) diseases transmit maternally and cause severe phenotypes. Since no effective treatment or genetic screening is available, nuclear genome transfer between patients’ and healthy eggs to replace mutant mtDNAs holds promises. Since polar body contains very few mitochondria and share same genomic material as oocyte, here we perform polar body transfer to prevent the transmission of inherited mtDNA variants. We compare the value of different germline genome transfer (spindle-chromosome, pronuclear, first and second polar body) in a mouse model. Reconstructed embryos support normal fertilization and produce live offspring. Strikingly, genetic analysis confirms F1 generation after polar body transfer possesses minimal donor mtDNA carry-over compared with spindle-chromosome (low/medium carry-over) and pronuclear (medium/high carry-over) transfer. Moreover, mtDNA genotype remains stable in F2 generation of progeny after polar body transfer. Our preclinical model demonstrates polar body transfer holds great potential in preventing the transmission of inherited mtDNA diseases. The objective of the present study was to detect genomic aberrations between PB1 and its counterpart, spindle-chromosome complex in human MII oocyte, PB2 and female pronucleus in human zygote at a single-cell level.
Project description:The data is a result of a large laboratory experiment targeting interactive effects of salinity and temperature on the transcriptomic level in algae from two populations of an ecologically relevant kelp species (Laminariales), Saccharina latissima. Research interest in S. latissima has recently been increasing given its importance as ecosystem engineer along temperate rocky shores in the Atlantic Ocean, and its growing potential in industrial applications such as aquaculture, pharmaceutics, food and feed. Young sporophytes of S. latissima were raised from stock cultures of clonal male and female gametophytes at the Alfred-Wegener-Institute Helmholtz Centre for Polar and Marine Research. Cultures originated from sporophyte collected at Kongsfjorden (79°N, 11°E; Spitsbergen, Norway) and at Roscoff (48° 43′ 39″ N, 3° 59′ 13.2″ W; Brittany, France). Sporophytes of both populations were grown aerated in glass beakers at 8°C and under a photon fluence rate of 20 µmol photons m–2 s–1 of photosynthetically active radiation with a 18 h light: 6 h dark photoperiod and were cultivated in sterile seawater enriched with Provasoli (Starr & Zeikus 1993) with an absolute salinity (SA) of ~30 during three months. At the start of the experiment, sporophytes were either kept at 8°C (or transferred to 0°C and 15°C) in temperature controlled rooms. After one week, per each temperature, sporophytes were divided into a low salinity treatment of SA 20 or kept at the control salinity (SA 30).
Project description:<p>The communities of marine bacteria that assemble around living microphytoplankton are predictably dominated by three taxonomic groups, each of which specializes in the use or transport of different components of the available metabolite pool: Rhodobacterales transport small and polar metabolites, Flavobacteriia use carbohydrate-rich polymers, and Gammaproteobacteria use compounds from both classes. The consistent ecological pattern involving these three taxa is widespread throughout the surface ocean, yet whether it reflects the outcome competition or niche partitioning of the phytoplankton-derived compounds is not clear. Addressing this question requires better knowledge than currently exists of the metabolites that link microbial autotrophs and heterotrophs in the surface ocean. Here we used two untargeted biological screening strategies that leverage bacterial proficiency for scavenging dilute substrates from chemically complex mixtures to characterize metabolite uptake by heterotrophic bacteria. In the first, expression patterns of transporters and diagnostic catabolic genes were analyzed in model marine bacteria grown individually in co-culture with the diatom Thalassiosira pseudonana. In the second, the ability of bacteria to draw down exometabolites from the culture medium was detected by novel approaches in mass spectrometry (MS) and nuclear magnetic resonance (NMR) analysis. These methods identified diverse chemical currencies mediating carbon transfer including low molecular weight metabolites (nucleosides, amino acids, organic acids, monomeric sugars, peptides, and sulfonates) and components of polysaccharides (chrysolaminarin, chitin oligomers, and alginate-like oligosaccharides). Bacterial utilization of bioreactive metabolites in the absence of competition indicated low resource overlap among strains and a dominance of resource partitioning over resource competition among the bacterial groups that process a major fraction of marine net primary production.</p><p><br></p><p><strong>NMR assay</strong> is reported in the current study <a href='https://www.ebi.ac.uk/metabolights/MTBLS1544' rel='noopener noreferrer' target='_blank'><strong>MTBLS1544</strong></a></p><p><strong>UPLC-MS assay</strong> is reported in <a href='https://www.ebi.ac.uk/metabolights/MTBLS1751' rel='noopener noreferrer' target='_blank'><strong>MTBLS1751</strong></a></p>