Project description:Enhanced vertical stratification brought about by warming of the ocean surface is expected to reduce vertical circulation and nutrient input with knock-on effects for phytoplankton. Increased nutrient limitation is one predicted outcome, but the response of phytoplankton is uncertain because long-term adaptation to nutrient limitation has not been studied. We used Cu as a model catalytic nutrient to explore the adaptive response of an oceanic diatom to continuous nutrient deprivation. Thalassiosira oceanica was maintained under Cu-limiting and sufficient conditions for more than 2000 generations and the evolved populations evaluated for physiological traits in a reciprocal transplant experiment. Adaptation to low Cu concentration increased Cu use efficiency, so that under Cu-limiting conditions T. oceanica maintained significantly faster rates of net C assimilation and growth than the control and ancestral populations.
Project description:Bacterial adaptation to nutrient limitation and increased population densities is central to survival and virulence. Surprisingly, <3% of Escherichia coli genes are known to play roles specific to the stationary phase. There is evidence that the leucine-responsive regulatory protein (Lrp) may play an important role in stationary phase, so this study used microarrays representing >98% of E. coli genes to more comprehensively identify those controlled by Lrp. The primary analysis compared isogenic Lrp(+) and Lrp(-) strains in cells growing in steady state in glucose minimal medium, either in the presence or absence of leucine. More than 400 genes were significantly Lrp-responsive under the conditions used. Transcription of 147 genes was lower in Lrp(+) than in Lrp(-) cells whether or not leucine was present; most of these genes were tightly coregulated under several conditions, including a burst of synthesis on transition to stationary phase. This cluster includes 56 of 115 genes already known to play roles in stationary phase. Our results suggest that the actual number of genes induced on entrance into stationary phase is closer to 200 and that Lrp affects nearly three-quarters of them, including genes involved in response to nutrient limitation, high concentrations of organic acids, and osmotic stress.
Project description:Identification of nutrient-specific microRNA expressed in Arabidopsis seedlings Small RNA sequencing of Arabidopsis wild type ecotype Columbia (Col-0) seedling under different nutrient limitation conditions
Project description:The goal of this study was to study this interaction by analyzing genome-wide transcriptional responses to four different nutrient-limitation regimes under aerobic and anaerobic conditions in chemostat cultures of S. cerevisiae. This ‘two-dimensional’ approach resulted in a new, robust set of ‘anaerobic’ and ‘aerobic’ signature transcripts for S. cerevisiae, as well as to a refinement of previous reports on nutrient-responsive genes. Moreover, the identification of genes regulated both by nutrient and oxygen availability provided new insight in cross-regulated network and hierarchy in the control of gene expression. Keywords = S. cerevisiae Keywords = oxygen availability Keywords = anaerobiosis Keywords = chemostat Keywords = transcriptome Keywords = nutrient limitation Keywords = carbon Keywords = nitrogen Keywords = sulfur Keywords = phosphorus. Keywords: other
Project description:Bacterial adaptation to nutrient limitation and increased population densities is central to survival and virulence. Surprisingly, <3% of Escherichia coli genes are known to play roles specific to the stationary phase. There is evidence that the leucine-responsive regulatory protein (Lrp) may play an important role in stationary phase, so this study used microarrays representing >98% of E. coli genes to more comprehensively identify those controlled by Lrp. The primary analysis compared isogenic Lrp(+) and Lrp(-) strains in cells growing in steady state in glucose minimal medium, either in the presence or absence of leucine. More than 400 genes were significantly Lrp-responsive under the conditions used. Transcription of 147 genes was lower in Lrp(+) than in Lrp(-) cells whether or not leucine was present; most of these genes were tightly coregulated under several conditions, including a burst of synthesis on transition to stationary phase. This cluster includes 56 of 115 genes already known to play roles in stationary phase. Our results suggest that the actual number of genes induced on entrance into stationary phase is closer to 200 and that Lrp affects nearly three-quarters of them, including genes involved in response to nutrient limitation, high concentrations of organic acids, and osmotic stress. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Computed