Project description:Nitrogen starvation is an efficient environmental pressure used to increase lipid accumulation and oil droplet formation in microalgal cells. Various studies focused on metabolic changes occurring in microalgae in nitrogen starvation conditions, but the mechanisms at the basis of these changes are not completely understood. Between microalgae, green algae, with more than 7000 species growing in a variety of habitats, have been frequently studied for energy purposes, but also as source of bioactive extracts/compounds. In this study, de novo transcriptome of the green algae Tetraselmis suecica has been performed in order to (1) deeply study its response to nitrogen starvation, (2) to look for enzymes with antioxidant capacity and for polyketide synthases (PKSs), (3) if present, to evaluate if nutrient starvation can influence their expression levels.
Project description:Proteins and peptides are minor components of vegetal oils. The presence of these compounds in virgin olive oil was first reported in 2001, but the nature of the olive oil proteome is still a puzzling question for food science researchers. In this project, we have compiled for a first time a comprehensive proteomic dataset of olive fruit and fungal proteins that are present at low but measurable concentrations in a vegetable oil from a crop of great agronomical relevance as olive (Olea europaea L.). Accurate mass nLC-MS data were collected in high definition direct data analysis (HD-DDA) mode using the ion mobility separation step. Protein identification was performed using the Mascot Server v2.2.07 software (Matrix Science) against an ad hoc database made of olive protein entries. Starting from this proteomic record, the impact of these proteins on olive oil stability and quality could be tested. Moreover, the effect of olive oil proteins on human health and their potential use as functional food components could be also evaluated. In addition, this dataset provides a resource for use in further functional comparisons across other vegetable oils, and also expands the proteomic resources to non-model species, thus also allowing further comparative inter-species studies.
Project description:To investigate the role of lncRNAs on lipid metabolism, we did RNAseq to find the difference among large yellow croaker fed with fish oil (FO), soybean oil (SO), olive oil (OO), and palm oil (PO) diets
Project description:Oil-bodies are sites of energy storage in many organisms including microalgae. As a first step toward understanding oil accumulation in algae, we took a proteomic approach on purified oil-body fraction from the model microalga Chlamydomonas reinhardtii grown under nitrogen deprivation. Among the 240 proteins (?2 peptides) identified by LC-MS/MS, 33 were putatively involved in metabolism of lipids (mostly acyl-lipids and sterols). Compared to a recently reported Chlamydomonas oil-body proteome, 19 additional proteins of lipid metabolism were identified, including a glycerol 3-phosphate acyltransferase (GPAT), a lysophosphatidic acid acyltransferase (LPAT) and a putative phospholipid:diacylglycerol acyltransferase (PDAT), spanning the key steps of the triacylglycerol synthesis pathway. In addition, proteins putatively involved in deacylation/reacylation, sterol synthesis, lipid signaling and lipid trafficking were found to be associated to the oil body fraction. This dataset thus provides evidence that in Chlamydomonas oil-bodies are not only storage compartments but also are dynamic structures likely to be involved in processes such as oil synthesis, degradation and lipid homeostasis. The proteins identified here should provide useful targets for genetic studies aiming at increasing our understanding of triacyglycerol synthesis and the role of oil-bodies in microalgal cell functions.
Project description:Shewanella spp. possess a broad respiratory versatility, which contributes to the occupation of hypoxic/anoxic environmental or host-associated niches. Here we observed a strain-specific induction of biofilm formation in response to supplementation with the anaerobic electron acceptors dimethyl sulfoxide (DMSO) and nitrate in a panel of Shewanella algae isolates. The respiration-driven biofilm response is not observed in DMSO and nitrate reductase deletion mutants of the type strain S. algae CECT 5071, and can be restored upon complementation with the corresponding reductase operon(s) but not by an operon containing a catalytically inactive nitrate reductase. The distinct transcriptional changes, proportional to the effect of these compounds on biofilm formation, include cyclic di-GMP (c-di-GMP) turnover genes. In support, ectopic expression of the c-di-GMP phosphodiesterase YhjH of Salmonella Typhimurium but not its catalytically inactive variant decreased biofilm formation. The respiration-dependent biofilm response of S. algae may permit differential colonization of environmental or host niches.
Project description:To assess the diurnal gene expression in gills of oyster Crassotrea gigas, gills of 6 oysters were pooled and analyzed by RNa-seq every 4h for 52h (i.e. 13 sampling times). This procedure was executed simultaneously for control oysters fed with the non-harmful algae Heterocapsa triquetra (H.t condition), and for oysters fed with the harmful algae Alexandrium minutum (A.m condition) (L:D 9:15). Alexandrium minutum exposure led to a remodeling of the cycling transcriptome in gills of Crassostrea gigas.