Project description:In this study, microarrays were used to investigate the larval cod transcriptome response to zooplankton supplementation in the diet.
Project description:The availability of polyunsaturated fatty acids (PUFAs) in food items influences the fitness of organisms at higher trophic levels. Omega 3 and omega 6 fatty acids are essential compounds that cannot be synthesised de novo in these animals. Especially the omega 3 PUFA eicosapentaenoic acid (EPA) is an important molecule, as it is a limiting nutritional component for growth and reproduction in numerous marine and freshwater zooplankton species. With our transcriptomic study in Daphnia magna we address the transcriptomic network behind the metabolism and conversion that is connected to physiological EPA-limitation under temperature stress (20°C vs. 15°C).
Project description:It is widely accepted that in many food webs, the trophic transfer efficiency among primary producers and herbivores is determined by the nutritional value of primary producers. In pelagic freshwater and marine ecosystems, secondary production by herbivorous crustacean zooplankton is often limited by the seston's content of essential ω3 polyunsaturated fatty acids (ω3 PUFAs). However, little is known about the genetic network behind the positive relationship between phytoplankton ω3 PUFA content and zooplankton growth and reproduction. In our experimental study, we analysed gene expression changes of the freshwater cladoceran Daphnia magna under different food regimes differing in their ω3 PUFA composition. To disentangle ω3 PUFA effects from other factors, we fed D. magna with different pure phytoplankton cultures (i.e., algal and cyanobacterial diets) with or without supplementing the essential ω3 PUFA eicosapentaenoic acid (EPA). As hypothesized, we observed enhanced growth on diets supplemented with EPA. We applied an Illumina RNA-seq approach to D. magna from different diet treatments to find and monitor genes that are regulated dependent on EPA availability. Of 26,646 potential protein products (mapped to the D. magna genome), we identified transcriptomic signatures driven by the different food sources. Further analyses revealed specific candidate genes involved in EPA metabolism, irrespective of the basal food source. This allows a first functional annotation of previously uncharacterized genes involved in the EPA-specific response of D. magna and may finally provide a link to molecular processes connected to ω3 PUFA metabolism and conversion and thus trophic transfer efficiency in pelagic food webs.
Project description:Transcriptome profiling of whole proboscis and body wall of the marine Polychaeta Glycera alba, adults, wild population (sex undiscriminated), collected from the muddy-sandy intertidal flats at W Portugal (2020). Transcriptome profiling of glandular and muscular regions of proboscis of the marine Polychaeta Hediste diversicolor, adults, wild population (sex undiscriminated), collected from the muddy-sandy intertidal flats at W Portugal (2019).
Project description:purpose:The large-scale reproduction of Phaeocystis globosa has caused serious damage to the marine ecosystem in the coastal waters of China. The outbreak of algae blooms depends on the competitive advantage of their heteromorphic life history: colonial formation is beneficial to resist zooplankton predation, and the single isolated cells can absorb nutrients rapidly. methods:For RNA exaction, the biomass was resuspended in 2 mL RNA extraction buffer (1:1 mix of aqua-phenol and buffer L [0.5% SDS, 10 mM EDTA, 0.2 M sodium acetate (pH 5), and 1:100 β-mercaptoethanol)] and then incubated with DNase I (Takara, Japan) for 30 min at 37 °C to remove genomic DNA. RNA quality analysis, library construction, sequencing, data filtering and mapping were performed by the Novogene Bioinformatics Technology Co., Ltd. (Beijing, China). results:Three biological replicates from GX-C and ST-C were ensured statistical comparability and reliability of data. Raw data ranged from 25, 608,632 to 35,516,726 reads per sample. After producing more than 24 million clean reads, removing low-quality sequences and adapter sequences. Additionally, 4386 genes were differentially expressed at statistically significant levels, which included 2268 up-regulated genes and 2118 down-regulated genes. Genes with significant differential expression were involved in several pathways, including starch and sucrose, phagosome, inositol phosphate metabolism, fatty acid degradation. conclusions: In summary, we can find that colonial cells have stronger carbon fixation capacity. It is not used to synthesize fatty acids as reserves of energy, but to secrete EPS. The reduction of fatty acid makes P. globosa become “low-quality food” and the formation of colony from EPS reduces the chance of being ingestion by zooplankton.
