Project description:Sequencing the metatranscriptome can provide information about the response of organisms to varying environmental conditions. We present a methodology for obtaining random whole-community mRNA from a complex microbial assemblage using Pyrosequencing. The metatranscriptome had, with minimum contamination by ribosomal RNA, significant coverage of abundant transcripts, and included significantly more potentially novel proteins than in the metagenome. Keywords: metatranscriptome, mesocosm, ocean acidification
Project description:Sequencing the metatranscriptome can provide information about the response of organisms to varying environmental conditions. We present a methodology for obtaining random whole-community mRNA from a complex microbial assemblage using Pyrosequencing. The metatranscriptome had, with minimum contamination by ribosomal RNA, significant coverage of abundant transcripts, and included significantly more potentially novel proteins than in the metagenome. Keywords: metatranscriptome, mesocosm, ocean acidification This experiment is part of a much larger experiment. We have produced 4 454 metatranscriptomic datasets and 6 454 metagenomic datasets. These were derived from 4 samples. The experiment is an ocean acidification mesocosm set up in a Norwegian Fjord in 2006. We suspended 6 bags containing 11,000 L of sea water in a Coastal Fjord and then we bubbled CO2 through three of these bags to simulate ocean acidification conditions in the year 2100. The other three bags were bubbled with air. We then induced a phytoplankton bloom in all six bags and took measurements and performed analyses of phytoplankton, bacterioplankton and physiochemical characteristics over a 22 day period. We took water samples from the peak of the phytoplankton bloom and following the decline of the phytoplankton bloom to analyses using 454 metagenomics and 454 metatranscriptomics. Day 1, High CO2 Bag and Day 1, Present Day Bag, refer to the metatranscriptomes from the peak of the bloom. Day 2, High CO2 Bag and Day 2, Present Day Bag, refer to the metatranscriptomes following the decline of the bloom. Obviously High CO2 refers to the ocean acidification mesocosm and Present Day refers to the control mesocosm. Raw data for both the metagenomic and metatranscriptomic components are available at NCBI's Short Read Archive at ftp://ftp.ncbi.nlm.nih.gov/sra/Studies/SRP000/SRP000101
Project description:Construction of a comprehensive spectral library for the coral reef fish, Acanthochromis polyacanthus, from both DIA and DDA MS runs. The spectral library was then used to quantify proteomes of individual fish exposed to different environmental conditions including ocean acidification and ocean warming. Proteomes were measured for both liver and brain tissue and differential expression between environmental conditions was analyzed.
Project description:In this research we present a transcriptomics analysis of the physiological response of a marine calcifier, Strongylocentrotus purpuratus, to ocean acidification, a decline in ocean pH that results from the absorption of anthropogenic carbon dioxide (CO2). Larvae were raised from fertilization to prism stage in seawater with elevated CO2 conditions based upon IPCC emissions scenario B1 (540ppm CO2) and A1FI (1020ppm CO2).
Project description:The filamentous diazotrophic cyanobacteria Trichodesmium spp. supply fixed nitrogen (N) to the N-depleted oligotrophic oceans where their growth is often limited by the low availability of phosphorus(P) and/or iron. Previous studies have mostly been focused on the effects of ocean acidification on Trichodesmium under nutrient sufficient or iron-limited conditions. Only a few studies have examined the impacts of ocean acidification on Trichodesmium grown at low P concentrations using non-steady-state batch cultures. Here we cultured Trichodesmium using P-limited continuous cultures (chemostat) to mimic steady-state oceanic low P condition, and used comparative NGS-derived Trichodesmium transcriptome profiling (RNA-seq) analysis to find differentially expressed genes and cellular pathways in response to acidification.
Project description:In this study we investigated how changes in pH and ocean chemistry consistent with the scenarios of the Intergovernmental Panel on Climate Change (IPCC) drive major changes in gene expression, respiration, photosynthesis and symbiosis of the coral, Acropora millepora, long before they affect biomineralization. Changes in gene expression were consistent with metabolic suppression, an increase in oxidative stress, apoptosis and symbiont loss. Other expression patterns demonstrated up-regulation of membrane transporters, as well as the regulation of genes involved in membrane cytoskeletal interactions and cytoskeletal remodeling. These widespread changes in gene expression emphasize the need to expand future studies of ocean acidification to include a wider spectrum of cellular processes, many of which may occur well before impacts on calcification. We applied a reference microarray design for the experiment outlined in the study, which was a three condition experiment of ocean acidification: control pH 8.0-8.2, medium pH 7.8-7.9 and high pH 7.6-7.7, and across three time points: time zero, day 1 and day 28. Samples from time zero and control treatments were used to generate the reference sample for the microarray hybridization experiments. A total of 27 microarrays were used in the entire experiment, 3 biological replicates per treatment and timepoint. Reference samples in each array was labeled with Cy3, and the actual experimental samples with Cy5.
Project description:In this study we investigated how changes in pH and ocean chemistry consistent with the scenarios of the Intergovernmental Panel on Climate Change (IPCC) drive major changes in gene expression, respiration, photosynthesis and symbiosis of the coral, Acropora millepora, long before they affect biomineralization. Changes in gene expression were consistent with metabolic suppression, an increase in oxidative stress, apoptosis and symbiont loss. Other expression patterns demonstrated up-regulation of membrane transporters, as well as the regulation of genes involved in membrane cytoskeletal interactions and cytoskeletal remodeling. These widespread changes in gene expression emphasize the need to expand future studies of ocean acidification to include a wider spectrum of cellular processes, many of which may occur well before impacts on calcification.
Project description:The association with photosymbiotic algae is crucial for the proliferation of many coral reef organisms, but increases their sensitivity to environmental changes. Large benthic foraminifera (LBF) are a diverse group of carbonate producers harboring algal photosymbionts. They act as key ecological engineers and are widely used as bioindicators. As in corals, elevated temperatures and light intensities are known to induce bleaching in LBF, but the combined effects of ocean acidification and warming remain unclear. To shed light into the adaptive physiology of LBF, we linked the assessment of the holobiont and photosymbiont physiological condition (mortality, growth, coloration, and chlorophyll a) to a bottom-up proteomics approach that allows the examination of cellular responses of host and symbionts simultaneously. In a two-months experiment, we exposed Amphistegina lobifera to the combined effects of ocean acidification (400, 1000 and 2800 ppm pCO2) and warming (28-control and 31°C). More than 1,000 proteins were identified by label-free mass spectrometry-based whole proteome analysis and assigned to the host or photosymbionts. Photopigment concentrations declined in response to elevated pCO2, visible by discoloration. These indicate the reduction of photosymbiont densities under ocean acidification, despite the fertilizing effects suggested for high inorganic carbon availability, and imply metabolic adjustments. Increases of proteolytic proteins suggest active host regulation of photosymbiont density in order to maintain homeostasis with its algal photosymbionts. Growth rates, however, were unaffected by elevated pCO2 levels at control temperatures, but high pCO2 levels (2800 ppm, pH 7.52) combined with thermal stress (31°C) impaired growth, though mortality and shell dissolution was negligible. While growth was unaffected by intermediate pCO2 levels (1000 ppm, pH 7.98) combined with ocean warming, this treatment induced the most distinct proteome responses. These include the regulation of ion transporters and host cytoplasmic proteins that likely abet calcification under ocean acidification. This study reveals a highly complex cellular response in both the host and the photosymbiont, which appears to facilitate a high resilience potential of A. lobifera to end of the century ocean conditions. Nevertheless, our results imply that when pCO2 levels rise above 1000 ppm during persistent ocean warming or extreme heating events these adaptive mechanisms become disrupted.