Project description:Diatoms are prominent marine microalgae, interesting not only from an ecological point of view, but also for their possible use for biotechnology applications. They can be cultivated in phototrophic conditions, using sunlight as the only energy source. Some diatoms, however, can also grow in mixotrophic mode, where both light and external reduced carbon contribute to biomass accumulation. In this study, we investigated the consequences of mixotrophy on the growth and metabolism of the pennate diatom Phaeodactylum tricornutum, using glycerol as a source of reduced carbon. Transcriptomic, metabolomic and physiological data indicate that glycerol affects the central-carbon, carbon-storage and lipid metabolism of the diatom. In particular, glycerol addition mimics some typical responses of nitrogen limitation on lipid metabolism at the level of TAG accumulation and fatty acid composition. However, this compound does not diminish photosynthetic activity and cell growth, at variance with nutrient limitation, revealing essential aspects of the metabolic flexibility of these microalgae and suggesting possible biotechnological applications of mixotrophy.
Project description:Here we use a transcriptomic approach to investigate the molecular underpinnings of thermal acclimation in the model diatom species Phaeodactylum tricornutum by comparing the differential gene expression in cultures acclimated to sub-optimal, optimal, and supra-optimal temperatures (10, 20 and 26.5 °C, respectively).
Project description:Diatoms played an essential role in marine primary productivity. Polysaccharide chrysolaminarin and neutral lipid, mainly TAG, were necessary carbon fixation in diatom Phaeodactylum tricornutum. Our study speculated on the metabolism pathway of chrysolaminarin, fatty acid, fatty acid β-oxidation and TAG. Transcriptional levels coordinated with carbon fixation metabolism pathway were conjoint analysis in this study.
Project description:An experiment was performed to determine the similarities on the RNA level between different conditions where cell division stops in the diatom Phaeodactylum tricornutum. Many of these conditions also increase the accumulation of lipids within the cell or impair photosynthesis. The different metabolic responses were evaluated and the dataset was mined for potential transcriptional regulators of these changes. The experimental setup was as follows: Cells from the pennate diatom Phaeodactylum tricornutum were grown in ESAW medium under continous fluorescent light at 21C in baffled shakeflasks. Exponentially growing cells were harvested by centrifugation and washed twice in 21gr/L NaCL to remove nutrients. Cells were subsequently resuspended in the five different media/conditions (control, darkness, no nitrate, no phosphate, nocodazole).
Project description:Here we use a transcriptomic approach to investigate the molecular underpinnings of thermal stress in the model diatom species Phaeodactylum tricornutum. We expose cultures to high temperature (optimal +8°C) and follow changes in gene expression through time (over a 12 hour period) in comparison to optimal conditions (20 °C).
Project description:Diatoms, which are important planktons widespread in various aquatic environments, are believed to play a vital role in primary production as well as silica cycling. The genomes of the pennate diatom Phaeodactylum tricornutum and the centric diatom Thalassiosira pseudonana have been sequenced, revealing some characteristics of the diatomsâ mosaic genome as well as some features of their fatty acid metabolism and urea cycle, and indicating their unusual properties. To identify microRNAs (miRNAs) from P. tricornutum and to study their probable roles in nitrogen and silicon metabolism, we constructed and sequenced small RNA (sRNA) libraries from P. tricornutum under normal (PT1), nitrogen-limited (PT2) and silicon-limited (PT3) conditions. A total of 13 miRNAs were identified. They were probable P. tricornutum-specific novel miRNAs. These miRNAs were differentially expressed in PT1, PT2 and PT3, and their potential targets were involved in various processes. Our results indicated that P. tricornutum contained novel miRNAs that differed from miRNAs of other organisms and that they might play important regulator roles in P. tricornutum metabolism.
Project description:Extensive gene methylation correlated strongly with transcriptional silencing and differential expression under specific conditions. DNA methylation and its role in gene regulation is conserved in stramenopile. Methylome of the whole genome of diatom phaeodactylum tricornutum.
Project description:Diatoms, which are important planktons widespread in various aquatic environments, are believed to play a vital role in primary production as well as silica cycling. The genomes of the pennate diatom Phaeodactylum tricornutum and the centric diatom Thalassiosira pseudonana have been sequenced, revealing some characteristics of the diatomsâ mosaic genome as well as some features of their fatty acid metabolism and urea cycle, and indicating their unusual properties. To identify microRNAs (miRNAs) from P. tricornutum and to study their probable roles in nitrogen and silicon metabolism, we constructed and sequenced small RNA (sRNA) libraries from P. tricornutum under normal (PT1), nitrogen-limited (PT2) and silicon-limited (PT3) conditions. A total of 13 miRNAs were identified. They were probable P. tricornutum-specific novel miRNAs. These miRNAs were differentially expressed in PT1, PT2 and PT3, and their potential targets were involved in various processes. Our results indicated that P. tricornutum contained novel miRNAs that differed from miRNAs of other organisms and that they might play important regulator roles in P. tricornutum metabolism. Constructing and sequencing small RNA (sRNA) libraries from P. tricornutum under normal (PT1), nitrogen-limited (PT2) and silicon-limited (PT3) conditions
