Project description:Investigating the impact of physiological carbon source (PCS) availability on the transcriptional profile of activated CD8+ T cells proliferating in vitro
Project description:How environmental nutrient availability impacts T cell metabolism and function remains poorly understood. Here, we report that the presence of physiologic carbon sources (PCSs) in cell culture medium broadly impacts glucose utilization by CD8+ T cells, independent of transcriptional changes in metabolic reprogramming. The presence of PCSs reduced glucose contribution to the TCA cycle and increased effector function of CD8+ T cells, with lactate directly fueling the TCA cycle. In fact, CD8+ T cells responding to Listeria infection preferentially consumed lactate over glucose as a TCA cycle substrate in vitro, with lactate enhancing T cell bioenergetic and biosynthetic capacity. Inhibiting lactate-dependent metabolism in CD8+ T cells by silencing lactate dehydrogenase A (Ldha) impaired both T cell metabolic homeostasis and proliferative expansion in vivo. Together, our data indicate that carbon source availability shapes T cell glucose metabolism and identifies lactate as a bioenergetic and biosynthetic fuel for CD8+ effector T cells.
Project description:Nutrient availability, in particular that of carbon (C) and nitrogen (N), is one of the most important factors for the regulation of plant metabolism and development. In addition to independent utilization, the ratio of C to N metabolites in the cell is also important for the regulation of plant growth including. Plants sense and respond to the balance of carbon (C) and nitrogen (N) nutrients (C/N-nutrient) available to them, a process called the C/N-nutrient response. We previously demonstrated that disrupted high C/low N stress condition promotes the senescence progression in Arabidopsis plants. However, the molecular basis of C/N-nutrient responsive senescence regulation remains unclear. In this study, we carried out proteome analysis of phosphorylation dynamics in response to high C/low N nutrient stress.
Project description:Exploring molecular details of carbon utilization trade-offs in galactose-evolved yeast Adaptively evolved yeast mutants on galactose for around 400 generations showed diminished growth and carbon uptake rates on glucose. Genome-scale approaches were applied to characterize the molecular genetic basis of these trade-offs in carbon source utilization. Engineered mutants showing trade-offs in a specific carbon uptake rate between both carbons were used as controls. The transcriptional responses of the evolved mutants were almost identical during growth on both carbon sources. These carbon-independent conserved patterns were clearly observed in specific pathways and genes. Up-regulation of PGM2, a confirmed beneficial genetic change for improving galactose utilization was preserved on both carbons. In addition, HXK1, GLK1 and genes involved in reserve carbohydrate metabolism were up-regulated, while HXK2 was down-regulated. Genes that have a transcription factor binding site for Gis1p, Rph1p, Msn2/4p and Nrg1p were up-regulated. These results indicated changes in the metabolic pathways involved in metabolism of both carbons and in nutrient signaling pathway. The concentration profile of trehalose and glycogen supported these findings. Mutations in RAS2 and ERG5 genes were selected because of their beneficial and neutral effect on galactose utilization, respectively in our previous study. Site-directed mutants containing galactose-beneficial mutations in RAS2 only resulted in a significant decrease in glucose utilization. Integration of all these analyses clearly suggest an antagonistic pleiotropic trade-off in carbon source utilization caused by changes in regulatory region, and we hereby demonstrate how systems biology can be used to gain insight into evolutionary processes at the molecular level. Yeast galactose evolved mutants having improved galactose availability were grown on aerobic batch with glucose as carbon source
Project description:Investigation of whole genome gene expression level changes in Streptomyces sp. SirexAA-E (ActE) when grown on different carbon sources. The results of this study demonstrate that ActE upregulates a small number of genes specific for the utilization of the avaliable carbon source. Cellulolytic Streptomyces sp. SirexAA-E (ActE), isolated from the pinewood-boring wasp Sirex noctilio, has a genome enriched for biomass utilization. The secreted proteomes obtained from growth on pure polysaccharides catalyzed hydrolysis of cellulose, mannan, and xylan with specific activities comparable to Spezyme CP, a commercial cellulase preparation. During reaction of an ActE secretome with cellulose, reducing sugar release was markedly stimulated in the presence of O2. ActE also expresses and secretes an expanded repertoire of enzymes during growth on natural and pre-treated biomass. These results indicate a new microbial contribution to biomass utilization that is widely distributed in natural environments by insects
Project description:Previous high-throughput studies in Gram-negative bacteria identified a large number of 3’UTR fragments that potentially function as sRNAs. Here we extensively characterise the MalH sRNA. We show that MalH is a stable degradation intermediate derived from the 3’ end of malG, which is part of the maltose uptake operon transcript malEFG. Unlike the majority of bacterial sRNAs, MalH is transiently expressed during the transition from the exponential to the stationary growth phase, suggesting that it contributes to adaptation to changes in nutrient availability. Over-expression of MalH reduces expression of general outer membrane porins and MicA, a repressor of the high-affinity maltose/maltodextrin transporter LamB. Disrupting MalH production and function significantly reduces lamB accumulation when maltose is the only available carbon source, presumably due to the accumulation of the MicA repressor. We propose that MalH is part of a regulatory network that, during the transition phase, directly or indirectly promotes accumulation of high-affinity maltose transporters in the outer membrane by dampening competing pathways.
Project description:Exploring molecular details of carbon utilization trade-offs in galactose-evolved yeast Adaptively evolved yeast mutants on galactose for around 400 generations showed diminished growth and carbon uptake rates on glucose. Genome-scale approaches were applied to characterize the molecular genetic basis of these trade-offs in carbon source utilization. Engineered mutants showing trade-offs in a specific carbon uptake rate between both carbons were used as controls. The transcriptional responses of the evolved mutants were almost identical during growth on both carbon sources. These carbon-independent conserved patterns were clearly observed in specific pathways and genes. Up-regulation of PGM2, a confirmed beneficial genetic change for improving galactose utilization was preserved on both carbons. In addition, HXK1, GLK1 and genes involved in reserve carbohydrate metabolism were up-regulated, while HXK2 was down-regulated. Genes that have a transcription factor binding site for Gis1p, Rph1p, Msn2/4p and Nrg1p were up-regulated. These results indicated changes in the metabolic pathways involved in metabolism of both carbons and in nutrient signaling pathway. The concentration profile of trehalose and glycogen supported these findings. Mutations in RAS2 and ERG5 genes were selected because of their beneficial and neutral effect on galactose utilization, respectively in our previous study. Site-directed mutants containing galactose-beneficial mutations in RAS2 only resulted in a significant decrease in glucose utilization. Integration of all these analyses clearly suggest an antagonistic pleiotropic trade-off in carbon source utilization caused by changes in regulatory region, and we hereby demonstrate how systems biology can be used to gain insight into evolutionary processes at the molecular level.
Project description:Investigation of whole genome gene expression level changes in Streptomyces sp. SirexAA-E (ActE) when grown on different carbon sources. The results of this study demonstrate that ActE upregulates a small number of genes specific for the utilization of the avaliable carbon source. Cellulolytic Streptomyces sp. SirexAA-E (ActE), isolated from the pinewood-boring wasp Sirex noctilio, has a genome enriched for biomass utilization. The secreted proteomes obtained from growth on pure polysaccharides catalyzed hydrolysis of cellulose, mannan, and xylan with specific activities comparable to Spezyme CP, a commercial cellulase preparation. During reaction of an ActE secretome with cellulose, reducing sugar release was markedly stimulated in the presence of O2. ActE also expresses and secretes an expanded repertoire of enzymes during growth on natural and pre-treated biomass. These results indicate a new microbial contribution to biomass utilization that is widely distributed in natural environments by insects Streptomyces sp. ActE was grown in minimal medium supplimented with 0.5% carbon source (glucose, sigmacell-20, xylan, chitin, cellobiose, or AFEX). Cells were grown for 7 days and total RNA was extracted from the cell pellet. At least 3 biological replicates were performed for each carbon source (glucose, 3; sigmacell, 3; xylan, 5; chitin, 3; cellobiose 3; AFEX 3). Each biological replicate contained 3 technical replicates. The complete dataset were RMA Background Corrected, quantile normalized, the RMA algorithm was utilized by DNAStar ArrayStar.