Microalgae biomass is considered a promising alternative feedstock for biodiesel production due to its high productivity of neutral lipids, especially under abiotic stress conditions. Among the unicellular microalgae that show this characteristic, Chlamydomonas reinhardtii appears as one of the most important model species with increased lipid production under abiotic stress conditions. In this study, we show that C. reinhardtii cells cultivated under mixotrophic condition supplemented with 0.1 M of NaCl rapidly raise their intracellular amount of neutral lipids without a reduction in their cellular growth rate, representing a promising condition for biomass production toward bioenergy applications. The nuclear proteome of these cells was investigated, and we identified 323 proteins with an enrichment of almost 60% of nuclear proteins in the total dataset. We found 61 proteins differentially regulated upon salt treatment, including proteins annotated in functional categories related to translation and nucleosome assembly functions. Additionally, we identified transcription factor proteins (TFs) and analyzed their likely transcription factor-binding regulatory elements, identifying target genes related to lipid metabolism and kinase functions, indicating possible regulatory pathways of lipid biosynthesis. Together, these data can help understand regulatory nuclear mechanisms, leading to an increase in lipids in the first 24 h of salt stress.

Magalhães, L.O. Characterization of ECF sigma factors in Pseudomonas aeruginosa PA14.

Microalgae biomass is considered a promising alternative feedstock for biodiesel production due to its high productivity of neutral lipids, specially under abiotic stress conditions. Among the unicellular microalgae that show this characteristic, Chlamydomonas reinhardtii appears as one of the most important model species that have increased lipids production under abiotic stress conditions. In this study, we show that cells cultivated under mixotrophic condition supplemented with 0.1 M of NaCl rapidly raises their amount of neutral lipids in C. reinhardtii without reduction of their cellular growth rate, being therefore a promising condition for biomass towards bioenergy production. The nuclear proteome of these cells was investigated where we identified 323 proteins with an enrichment of almost 60% of nuclear proteins in the total dataset. We found 61 proteins differentially regulated upon salt treatment, including proteins annotated in functional categories related to translation and nucleosome assembly functions, among others. Additionally, we identified Transcription factor proteins (TFs) and analyzed their likely Transcription factors-binding regulatory elements identifying target genes related to lipids metabolism and kinase functions, indicating possible regulatory pathways of lipids biosynthesis. Together these data can help understand regulatory nuclear mechanisms leading to an increase of lipids in the first 24h of salt stress 0.1M NaCl.