Project description:This experiment was conducted in order to evaluate the potential contribution of oil droplets to the toxicity of dispersed oil to fish larvae. Atlantic cod larvae were exposed to five concentrations of either dispersed oil (D1-D5) (containing oil droplets [medium size 10-14 µm based on volume] and water soluble fraction [WSF]) or the filtered dispersion containing only WSF of oil (W1-W5) for four days and harvested for transcriptional analysis at 13 days post hatching. The most significant differently expressed genes were observed in cod larvae exposed to the highest concentration of the dispersed oil (containing 10.41 ± 0.46 µg ∑PAH/L), with CYP1A showing the strongest response. Functional analysis further showed that the top scored network as analyzed with Ingenuity Pathway Analysis was “Drug Metabolism, Endocrine System Development and Function, Lipid Metabolism”. Oil exposure also increased the expression of genes involved in bone resorption and decreased the expression of genes related to bone formation. In conclusion, oil exposure affects drug metabolism, endocrine regulation, cell differentiation and proliferation, apoptosis, fatty acid biosynthesis and tissue development in Atlantic cod larvae. The altered gene transcription was dominated by the WSF and the oil droplet fraction only had a moderate impact on the observed changes.
Project description:In this study, microarrays were used to investigate the larval cod transcriptome response to zooplankton supplementation in the diet.
Project description:Vertebrates are colonized at birth by complex microbial communities (microbiota) that influence diverse aspects of host biology. We have used a functional genomics approach to identify zebrafish genes that are differentially expressed in response to the microbiota. We assessed RNA expression profiles from zebrafish larvae at 6 days post-fertilization (dpf) that were either raised continuously in the absence of any microorganism (germ-free or GF), or raised GF through 3dpf then colonized with a normal zebrafish microbiota (conventionalized or CONVD). Total RNA was purified from pooled intact zebrafish larvae (28-80 larvae/pool, 3 biological replicate pools/condition) using Trizol reagent (Invitrogen) followed by DNase I digestion (DNA-Free, Ambion) according to manufacturers' protocols. Total RNA from each replicate pool (12ug RNA/replicate) was used as template for independent cDNA synthesis and in vitro transcription reactions (BioArray HighYield RNA Transcript Labeling Kit; Enzo Life Sciences) to generate biotinylated cRNA targets. cRNA targets (20ug/replicate) were fragmented using standard methods. Hybridization and scanning were performed using standard Affymetrix protocol. Raw expression values were normalized (Invariant set method) and modeled (PM-MM model), and present/absent calls were generated using dChip software (build date Dec.11, 2005).
Project description:The main object of this study was to evaluate the impact of different levels of vitamin A (VA) and arachidonic acid (ARA) in relation to eicosapentaenoic acid (EPA) on mineralization and gene expression in Atlantic cod larvae (Gadus morhua). A two-way factorial design was used to identify possible interactions between the nutrients. First-feeding larvae were fed enriched rotifers from start-feeding until 29 days post hatch (dph). Larvae in four tanks were fed one of the following diets: control (EPA/ARA ratio: 15.8, 0.9 µg VA g-1 wet wt.), control+VA (EPA/ARA ratio: 15.8, 7.8 µg VA g-1 wet wt.), High ARA (EPA/ARA ratio: 0.9, 1.5 µg VA g-1 wet wt.) or High ARA +VA (EPA/ARA ratio: 0.9, 12.0 µg VA g-1 wet wt.). There was no difference in survival (33-40%) between the groups. Larvae fed High ARA+VA were shorter at 29 dph. The larvae fed High ARA+VA had significantly less mineralized bones, showing significant interaction effects between VA and ARA. Although transcriptomic analysis using a custom-made microarray did not reveal any interaction effects, it was found that high ARA diets altered the transcription of more genes than control +VA diets. Furthermore, blgap1 , blgap2 and col10a1 were all down-regulated in larvae fed High ARA-diets and to a lesser extent by Control +VA diet. Lower expression in the High ARA+VA diets compared to ARA and VA diets indicated an additive effect on mineralization. In conclusion, this study showed that the dietary increase in ARA and VA altered the skeletal metabolism during larval A. cod development, most likely through signaling pathways specific for each nutrient rather than an interaction. The present study also demonstrates that VA could affect the larval response to ARA, even within the accepted non-toxic/non-deficient range.
Project description:The use of dispersants can be an effective way to deal with acute oil spills to limit environmental damage, however very little is known about whether chemically dispersed oil have the same toxic effect on marine organisms as mechanically dispersed oil. We exposed Atlantic cod larvae to chemically and mechanically dispersed oil for four days during the first-feeding stage of development, and collected larvae at 14 days post hatch for transcriptional analysis. A genome-wide microarray was used to screen for effects and to assess whether molecular responses to chemically and mechanically dispersed oil were similar, given the same exposure to oil (droplet distribution and concentration) with and without the addition of a chemical dispersant (Dasic NS).
Project description:The Atlantic cod (Gadus morhua L.) is one of the most important species in the Baltic Sea with high ecological and economical value. To explore the differences in adaptation to salinity between Baltic cod subpopulation: western (Kiel Bight) and eastern (Gdańsk Bay) samples were analyzed through genome-wide oligonucleotide microarray.
Project description:The Atlantic cod (Gadus morhua L.) is one of the most important species in the Baltic Sea with high ecological and economical value. To explore the differences in adaptation to salinity between Baltic cod from different regions, western (Kiel Bight) and eastern (Gdańsk Bay) samples were analyzed through oligonucleotide microarray.
Project description:Vertebrates are colonized at birth by complex microbial communities (microbiota) that influence diverse aspects of host biology. We have used a functional genomics approach to identify zebrafish genes that are differentially expressed in response to the microbiota. We assessed RNA expression profiles from zebrafish larvae at 6 days post-fertilization (dpf) that were either raised continuously in the absence of any microorganism (germ-free or GF), or raised GF through 3dpf then colonized with a normal zebrafish microbiota (conventionalized or CONVD).