Project description:Microalgal lipid, a feasible substrate for biofuel, is typically accumulated during the stationary growth phase. Generating strains which trigger lipogenesis from the exponential growth phase will enhance lipid productivity, reduce cost of biofuel production. We characterized a lipid-rich microalgal mutant, Dunaliella tertiolecta, which exhibited a six-fold enhancement of neutral lipids production in the exponential growth phase with marginal compromise on growth (4%). Using transcriptomics and metabolomics, regulatory mechanisms of the mutant were uncovered.
Project description:Microarrays offer a comprehensive tool for a system-wide analysis of cell functioning based on the simultaneous detection of the activity of thousands of genes. While transcriptome analyses are usually related with the study of gene expression and regulation within single species in laboratory experiments or environmental samples, in the present study, the possibility of studying gene expression in river biofilm communities was explored. To this aim a Functional Gene array (FGA), based on consensus sequences from genes of key physiological processes, was designed including 83 functional genes chosen to reflect several essential biochemical pathways and specific stress response pathways. Probes of these genes were designed from consensus sequences from up to 6 microalgal species (diatoms and chlorophytes). Furthermore, species specific probes were included resulting in 1556 unique oligonucleotide probes for 83 different genes. RNA extracted from Chlamydomonas reinhardtii, Scenedesmus vacuolatus and multi-species biofilms was then hybridized to oligonucleotide arrays at different hybridization temperatures (55, 60 and 65ºC). Signal intensity was affected by sequence divergence but results showed that hybridisation temperature of 55ºC allowed a good compromise between cross-hybridization and specificity. Due to the limited number of probes and available sequence information the designed FGAs is at present particularly useful for the comparison of similar biofilms exposed to different conditions in laboratory experimental studies.