Project description:Atlantic salmon (Salmo salar) move from fresh- to seawater environments following a seasonally timed preparative transition called smoltification, which takes place under photoperiodic control in the freshwater environment. In masu salmon (Oncorhynchus masou), coordination of photoperiodic sexual maturation is proposed to involve in a fish-specific circumventricular organ, the saccus vasculosus (SV), through its intrinsic opsin-based light sensitivity, thyrotrophin secretion and modulation of deiodinase activity (TSH-DIO cascade). The saccus vasculosus is a highly vascularized structure located on the ventral side of the hypothalamus and its interface between the blood and cerebrospinal fluid also hints at a role in ionic balance of the cerebrospinal fluid (CSF). Both the potential photoperiodic and ionic functions of the SV led us to perform transcriptome analysis of the SV in smoltification in Atlantic salmon. Our data show that SV response to seawater exposure is highly dependent on photoperiodic history and identifies ependymin as a major secretory output of the SV, consistent with a role in control of CSF composition. Conversely, we could not detect crucial elements of the opsin-TSH-DIO cascade suggesting that the photoperiodic history-dependence of the SV to seawater exposure is unlikely to stem from SV-intrinsic responses to photoperiod.
Project description:The soft coral Scleronephthya gracillimum is an azooxanthellate octocoral order Alcyonacea. In this study, stress responses to increased seawater temperature and marine acidification were investigated using a microarray. The S. gracillimum microarray was constructed. The S. gracillimum microarray was constructed after RNA-seq. Oligonucleotides were picked from UniGene of S. gracillimum and the clones were annotated using Blast.
Project description:A short-term microcosm experiment was conducted to evaluate the impact of wastewater discharge on coastal microbial communities. Coastal seawater was exposed to two types of treated wastewater: (i) unfiltered wastewater, containing nutrients, pollutants, and allochthonous microbes, and (ii) filtered wastewater, which retained only nutrients and pollutants while removing microbial components. Metaproteomic samples were collected from the coastal seawater prior to the experiment and from each experimental flask at the late exponential growth phase to assess microbial functional responses to wastewater exposure.
Project description:We report the full transcriptome (RNA-Seq) of Vibrio fischeri ES114 in rich medium, seawater, and after venting from the Hawaiian bobtail squid Euprymna scolopes. We also report the effects of ribodepletion on low-biomass samples, down to input amount of 1ng total RNA.
Project description:Fish gills represent a complex organ that perform multiple physiological functions and is composed of several cell types. Among these cells, ionocytes are implicated in the maintenance of ion homeostasis. However, because the ionocyte represents only a small percent of whole gill tissue, its specific transcriptome can be overlooked among the numerous cell types included in the gill. The objective of this study is to better understand ionocyte functions by comparing the RNA expression of this cell type in freshwater and seawater adapted rainbow trout. To realize this objective, ionocytes were captured from gill cryosections using laser capture microdissection after immunohistochemistry. Then, transcriptome analyses were performed on an Agilent trout oligonucleotide microarray. Gene expression analysis identified 108 unique annotated genes differentially expressed between freshwater and seawater ionocytes, with a gene fold higher than 3. Most of these genes were up regulated in freshwater cells. Interestingly, several genes implicated in ion transport, extracellular matrix and structural cellular proteins appeared up regulated in freshwater ionocytes. Among them, several ion transporters, such as CIC2, SLC26A6, and NBC, were validated by qPCR and/or in situ hybridization. The latter technique allowed us to localize the transcripts of these ion transporters in only ionocytes and more particularly in the freshwater cells. Genes involved in metabolism and also several genes implicated in transcriptional regulation, cell signaling and the cell cycle were also over-expressed in freshwater ionocytes. In conclusion, laser capture microdissection combined with microarray analysis allowed for the determination of the cell signature of scarce cells in fish gills, such as ionocytes, and aided characterization of the transcriptome of these cells in freshwater and seawater adapted trout.
Project description:Schwanniomyces etchellsii is an unconventional, halotolerant microorganism. Like some other yeasts, it can efficiently perform various biocatalytic transformations of organic compounds in seawater more effectively than in freshwater. In seawater, conversion rates are higher, by-product production is minimized, greater substrate loading is possible, and cells can be recycled for further use. To identify the molecular features that explain this behavior, comparative proteomic and lipidomic studies were conducted on cells grown in seawater and freshwater at various growth stages. The results showed higher expression of proteins involved in the stress response, such as glycerol-3-phosphate dehydrogenase, the glycerol transporter Stl1 and the P-type ATPase sodium pump Ena1, and several phospholipid biosynthesis proteins, including inositol-3-phosphate synthase and phosphatidate cytidylyltransferase, in seawater. Changes in metabolic enzymes and other proteins involved in responding to stimuli were also observed between the two conditions. Overall, cells grown in a freshwater medium exhibited higher levels of enzymes involved in biosynthetic processes. Differences in lipid profiles were also observed between cells grown in the two media. Higher levels of monoacyl and diacylglycerols were found in seawater, while higher levels of phospholipids containing serine and ethanolamine were found in freshwater. Consistent with more permeable membranes, cells grown in seawater exhibited lower levels of ergosterol.