Project description:Fatty acid synthesis is closely linked to nutrient availability and cellular energetic status. The committed step in fatty acid synthesis is the acetyl CoA carboxylase. Eukaryotes have two genes encoding acetyl CoA carboxylases, one encoding a cytosolic enzyme and another coding for a mitochondrial enzyme. They catalyze the synthesis of malonyl CoA in the cytosol and the mitochondria, respectively. While cytosolic malonyl CoA is the precursor for fatty acid synthesis, mitochondrial malonyl CoA controls the transfer of fatty acyl group into the mitochondria by inhibiting carnitine/palmitoyl transferase activity and thus, regulates β-oxidation. In Saccharomyces cerevisiae, β-oxidation is restricted to the peroxisomes, raising the question of the function of the mitochondrial isoform (HFA1). In this study, we replaced the cytosolic Acc1 with Hfa1 expressed in the cytosol by removing the mitochondrial leader peptide, under control of the HFA1 promoter. We studied fatty acid synthesis and transcription profiles in this strain during starvation for carbon or nitrogen, using glucose or ethanol as the carbon source. Under all the conditions studied, the key sensor of energetic status, Snf1, was activated, indicating active inhibition of fatty acid synthesis. The pool size of fatty acids was smaller when Acc1 was replaced with truncated Hfa1 for fatty acid synthesis. Yet, the transcription profiles were similar in both the cases. These results point towards the conclusion that Hfa1 is either catalytically less efficient or it is more sensitive to inhibition by Snf1. Gene expression from a strain of Saccharomyces cerevisiae where cytosolic fatty acid synthesis occurs by mitochondrial acetyl CoA carboxylase (without its mitochondrial leader peptide) is compared with that in a reference strain while growing in chemostats on carbon or nitrogen starvation using glucose or ethanol as the carbon source.
Project description:Fatty acid synthesis is closely linked to nutrient availability and cellular energetic status. The committed step in fatty acid synthesis is the acetyl CoA carboxylase. Eukaryotes have two genes encoding acetyl CoA carboxylases, one encoding a cytosolic enzyme and another coding for a mitochondrial enzyme. They catalyze the synthesis of malonyl CoA in the cytosol and the mitochondria, respectively. While cytosolic malonyl CoA is the precursor for fatty acid synthesis, mitochondrial malonyl CoA controls the transfer of fatty acyl group into the mitochondria by inhibiting carnitine/palmitoyl transferase activity and thus, regulates β-oxidation. In Saccharomyces cerevisiae, β-oxidation is restricted to the peroxisomes, raising the question of the function of the mitochondrial isoform (HFA1). In this study, we replaced the cytosolic Acc1 with Hfa1 expressed in the cytosol by removing the mitochondrial leader peptide, under control of the HFA1 promoter. We studied fatty acid synthesis and transcription profiles in this strain during starvation for carbon or nitrogen, using glucose or ethanol as the carbon source. Under all the conditions studied, the key sensor of energetic status, Snf1, was activated, indicating active inhibition of fatty acid synthesis. The pool size of fatty acids was smaller when Acc1 was replaced with truncated Hfa1 for fatty acid synthesis. Yet, the transcription profiles were similar in both the cases. These results point towards the conclusion that Hfa1 is either catalytically less efficient or it is more sensitive to inhibition by Snf1. Gene expression from a strain of Saccharomyces cerevisiae where cytosolic fatty acid synthesis occurs by mitochondrial acetyl CoA carboxylase (without its mitochondrial leader peptide) is compared with that in a reference strain while growing in chemostats on carbon or nitrogen starvation using glucose or ethanol as the carbon source. There are two strains (reference or mutant), two carbon sources (glucose or ethanol) and two limitations (carbon or nitrogen), resulting in 8 comparisons. Each array was performed in duplicate, resulting in 16 CEL files. Growth was limited by either carbon or nitrogen. When carbon was the limited nutrient, we tested growth on either glucose or ethanol (both using ammonium sulfate as the nitrogen source). When ammonium sulfate was limiting, we used either glucose or ethanol as the carbon source.
Project description:Saccharomyces cerevisiae IMS0002 which, after metabolic and evolutionary engineering, ferments the pentose sugar arabinose. Glucose and arabinose-limited anaerobic chemostat cultures of IMS0002 and its non-evolved ancestor IMS0001 were subjected to transcriptome analysis to identify key genetic changes contributing to efficient arabinose utilization by strain IMS0002.
2011-03-01 | GSE27539 | GEO
Project description:Anaerobic microbial community producing medium-chain fatty acids from lignocellulosic conversion residue
Project description:Saccharomyces cerevisiae IMS0002 which, after metabolic and evolutionary engineering, ferments the pentose sugar arabinose. Glucose and arabinose-limited anaerobic chemostat cultures of IMS0002 and its non-evolved ancestor IMS0001 were subjected to transcriptome analysis to identify key genetic changes contributing to efficient arabinose utilization by strain IMS0002. Glucose- and arabinose limited anaerobic chemostat cultivation of strains IMS0002 and glucose limited IMS0001 at D= 0.03 h-1
Project description:Metabolic engineering of Saccharomyces cerevisiae for efficient monoterpenes production was mostly restricted by the limited tolerance to these chemicals. Understanding of the molecular mechanisms underlying the tolerance of S. cerevisiae to monoterpenes was essential for the de novo biosynthesis these chemicals in S. cerevisiae. In this study, commercial oligonucleotide microarray assays were performed to investigate the global response of S. cerevisiae to typical monoterpene D-limonene under transcriptional level. Yeast cell treated with sublethal dose of D-liomonene, gene change profiles were investigated at transcription level and the microarry data were also verified with quantitative real time PCR. D-limonene induced gene expression in Saccharomyces cerevisiae at early logarithmic phase was measured at 2 hours after exposure to doses of 0.02% (v/v) D-limonene. Three independent experiments were performed for each experiment (control or 2 hours).
Project description:Metabolic engineering of Saccharomyces cerevisiae for efficient monoterpenes production was mostly restricted by the limited tolerance to these chemicals. Understanding of the molecular mechanisms underlying the tolerance of S. cerevisiae to monoterpenes was essential for the de novo biosynthesis these chemicals in S. cerevisiae. In this study, commercial oligonucleotide microarray assays were performed to investigate the global response of S. cerevisiae to typical monoterpene D-limonene under transcriptional level. Yeast cell treated with sublethal dose of D-liomonene, gene change profiles were investigated at transcription level and the microarry data were also verified with quantitative real time PCR.
2013-12-23 | GSE34665 | GEO
Project description:Bacteria and Archaea ecology of medium chain fatty acids production from wastes leachates fermentation
Project description:Purpose: The goals of this study are to find out the differential expression genes in the fadR mutant strain(ΔfadR) compared with wild-type (WT) and to further explore the regulation mechanisms of fadR. Methods: Shewanella oneidensis MR-1 WT and ΔfadR were collected in log phage(OD~0.6). RNA extraction was performed using the RNeasy minikit (Qiagen) and the RNA was quantified by using a NanoVue spectrophotometer (GE Healthcare). RNA seq was performed using Illumina NextSeq 500, 2×150 bp. Results: Our study represents that the expression of 146 genes were decreased and 94 genes were increased inΔfadR compared with WT. Branched-chain keto acid dehydrogenase (BKD) produces corresponding branched-chain acyl coenzyme A which further participating branchend-chain fatty acids synthesis. The expression of bkdA2 was also promoted in △fadR compared with WT. Conclusions: Combined with our expression results, it declared that FadR can suppress bkd operon in some degree,which further increase the synthesis of branched-chain fatty acids in ΔfadR.