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:To investigate the mechanism by which the microalgae-yeast co-culture system promotes wastewater denitrification. We concluded that microalgae and yeast exhibit a mutually beneficial relationship in the co-culture system. Microalgae nitrogen metabolism can be influenced by both miRNA and mRNA, and the presence of yeast stimulates gene expression in microalgae.
Project description:Background: Marine phytoplankton are responsible for 50% of the CO2 that is fixed annually worldwide and contribute massively to other biogeochemical cycles in the oceans. Diatoms and coccolithophores play a significant role as the base of the marine food web and they sequester carbon due to their ability to form blooms and to biomineralise. To discover the presence and regulation of short non-coding RNAs (sRNAs) in these two important phytoplankton groups, we sequenced short RNA transcriptomes of two diatom species (Thalassiosira pseudonana, Fragilariopsis cylindrus) and validated them by Northern blots along with the coccolithophore Emiliania huxleyi. Results: Despite an exhaustive search, we did not find canonical miRNAs in diatoms. The most prominent classes of sRNAs in diatoms were repeat-associated sRNAs and tRNA-derived sRNAs. The latter were also present in E. huxleyi. tRNA-derived sRNAs in diatoms were induced under important environmental stress conditions (iron and silicate limitation, oxidative stress, alkaline pH), and they were very abundant especially in the polar diatom F. cylindrus (20.7% of all sRNAs) even under optimal growth conditions. Conclusions: This study provides first experimental evidence for the existence of short non-coding RNAs in marine microalgae. Our data suggest that canonical miRNAs are absent from diatoms. However, the group of tRNA-derived sRNAs seems to be very prominent in diatoms and coccolithophores and may be used for acclimation to environmental conditions.
Project description:Arthrospira platensis C1, a filamentous cyanobacterium, is one of the most commercially successful microalgae. However, high temperature stress is a critical problem that alters metabolic functions and causes irreversible damage during the growth of microorganisms, resulting in a loss of biomass productivity and high-value compounds. The investigation of genome-wide expression changes can provide towards a better understanding on the cellular stress responses.
Project description:Cells are subjected to dramatic changes on gene expression upon environmental changes. Stress causes a general down-regulation of gene expression together with the induction of a set of stress-responsive genes. Genome wide localisation studies showed major changes on Pol II localisation towards stress-responsive genes in contrast to housekeeping genes. Pol II relocalisation requires of the Hog1 SAPK, which also associates at stress-responsive loci. Chromatin structure was not significantly altered upon stress except for those genes that displayed Hog1 association. Together, Hog1 serves to bypass the general down-regulation of gene expression by targeting RNA Pol II machinery and inducing chromatin remodeling at stress-responsive loci. Hog1 and Pol II ChIP-Seq and Mnase-Seq experiments in both strains WT and Hog1 mutant, for 2 conditions: Exposed and not exposed to osmostress
Project description:Background: Marine phytoplankton are responsible for 50% of the CO2 that is fixed annually worldwide and contribute massively to other biogeochemical cycles in the oceans. Diatoms and coccolithophores play a significant role as the base of the marine food web and they sequester carbon due to their ability to form blooms and to biomineralise. To discover the presence and regulation of short non-coding RNAs (sRNAs) in these two important phytoplankton groups, we sequenced short RNA transcriptomes of two diatom species (Thalassiosira pseudonana, Fragilariopsis cylindrus) and validated them by Northern blots along with the coccolithophore Emiliania huxleyi. Results: Despite an exhaustive search, we did not find canonical miRNAs in diatoms. The most prominent classes of sRNAs in diatoms were repeat-associated sRNAs and tRNA-derived sRNAs. The latter were also present in E. huxleyi. tRNA-derived sRNAs in diatoms were induced under important environmental stress conditions (iron and silicate limitation, oxidative stress, alkaline pH), and they were very abundant especially in the polar diatom F. cylindrus (20.7% of all sRNAs) even under optimal growth conditions. Conclusions: This study provides first experimental evidence for the existence of short non-coding RNAs in marine microalgae. Our data suggest that canonical miRNAs are absent from diatoms. However, the group of tRNA-derived sRNAs seems to be very prominent in diatoms and coccolithophores and may be used for acclimation to environmental conditions. RNA-seq study of sRNA populations in two species of diatoms using Illumina GAII high-throughput sequencing
Project description:Although it is well established the seasonal effect of the photoperiod over the transcriptional expression patterns in plants, this effect has not been studied in microalgae. Here we fill the gap using the model microalgae Ostreococcus tauri.
2023-08-31 | GSE155535 | GEO
Project description:microalgae and methanotroph sequencing under bentazone stress