Project description:LaeA, a putative methyltransferase, is a global regulator for metabolic and development process in filamentous fungi. We characterized the laeA homologous genes in the white koji fungus, Aspergillus luchuensis mut. kawachii (A. kawachii) to examine their role in citric acid production. The ΔlaeA strain showed a significant reduction in the citric acid productivity. The cap-analysis gene expression (CAGE) revealed the laeA is required for the gene expression of a putative citrate exporter encoding cexA, which has a critical role for the citric acid production. The deficient citric acid productivity of the ΔlaeA strain was remedied by overexpression of cexA to a comparative level to that of the cexA overexpressing ΔcexA strain. In addition, chromatin immunoprecipitation coupled with quantitative PCR (ChIP-qPCR) analysis indicated that LaeA regulates gene expression of the citrate exporter encoding cexA gene via histone H3K4 and histone H3K9 methylation levels. These results indicate that LaeA is involved in the citric acid production through epigenetic regulation of cexA in A. kawachii.
Project description:Purpose of study was to investigate whole genome expression changes of a strain with deletion of the two-component system TctD-TctE and determine genes dysregulate relative to the parental wildtype to gain insight into possible regulatory targets of TctD-TctE. TctD-TctE is a two-component system in Pseudomonas aeruginosa that responds to and regulates uptake of tricarboxylic acids such as citric acid. It accomplishes this through derepression of the porin encoding the gene opdH, thereby regulating influx of citrate metabolites from the surrounding environment. Deletion of the tctED operon (ΔtctED) resulted in a reduced growth phenotype when citric acid is present in media. In the ΔtctED strain the presence of citric acid was found to have an inhibitory effect on growth. When the alternative carbon source arginine was present, wildtype levels of growth could not be restored. Static cultures of ΔtctED had low cell density in the presence of citric acid but maintained the same levels of biofilm formation compared to conditions when no citric acid was present. This suggests a dysregulation of biofilm formation in the presence of citric acid. In the ΔtctED strain there was also greater accumulation of tobramycin within the biofilm compared to the PA14 wildtype strain. Additionally, analysis of whole-genome expression found that multiple metabolic genes were dysregulated in ΔtctED. Here it is concluded that TctD-TctE is involved in biofilm tolerance to tobramycin in the presence of citrate metabolites.
2018-05-15 | GSE114431 | GEO
Project description:citric acid on paddy soil microbes
Project description:In this study, we profiled the transcriptional changes in a polyphagous spider mite, Tetranychus urticae, after adaptation to spatial and tempospatial stress. We show heritable down-regulation of genes encoding for core enzymes involved in the citric acid and gluconeogenesis/glycolyse pathways (glucose 6-phosphatase among others). Additionally, we observe heritable transcriptional changes in amino acid pathways (methionine, tyrosine and phenylalanine) and in laterally acquired genes from bacteria (cobalamin-independent methionine synthase). By similiar study results in other organisms, we argue that these heritable transcriptional changes (partially) underpin the changed life history traits observed in our experimental evolution set-up.
Project description:Sirtuin is considered to play a significant role in the growth phase-dependent gene expression. In this study, we characterized sirtuin in the white koji fungus, Aspergillus kawachii, to examine their role on regulation of amylolytic enzymes and citric acid productions during the solid-state culture (koji). Characterization of rice-koji made using five putative sirtuin gene disruptants indicated that they are involved in amylolytic activity and acidity of rice koji; especially the sirD disruptant showed lower levels of α-amylase activity and citric acid production per mycelial weight in the koji compared the control strain. In addition, the sirD disruptant also showed a change in mycelial pigmentation, higher sensitivity to cell wall biogenesis inhibitor such as calcofluor white and Congo red, and reduced conidia formation, indicating that SirD is required for secondary metabolism, cell wall integrity, and conidial development. The cap analysis gene expression (CAGE) indicated that the transcriptional changes related to the characteristic phenotype of the sirD disruptant (e.g., a reduced transcript level of acid-stable α-amylase gene and a citric acid exporter) in rice koji. These results indicated that SirD has a significant role on the global transcriptional regulation including productions of α-amylase and citric acid in A. kawachii during the solid-state fermentation process.
Project description:The goal of this study is to find out how Yarrowia lipolytica W29’s transcriptome changes in response to different pHs in certain medium, where the production of citric acid and lipid vary significantly at different pHs. The changes in transcriptome will give us insight about the mechanism of citric acid and/or lipid production are regulated. We harvested Y. lipolytica cells from bioreactor cultures from three different pHs: 2.0, 4.0 and 6.0 in triplicates. We sequenced the mRNA by Illumina HiSeq 2500 and generated an average of 20 million reads for each sample. We did not find distinct gene expression changes for the enzymes right downstream the intersection where citrate is cleaved into acetyl-CoA. Instead, from gene ontology enrichment analysis, we observed proteins with transport activities were overrepresented in gene groups that were up-regulated higher pH conditions, where citric acid secretion is favored.
Project description:Among all the evaluated factors, only adipose tissue insulin sensitivity (assessed by clamped % suppression of serum free fatty acid), serum concentration of high molecular weight adiponectin, and plasma concentration of TCA cycle metabolites such as citric acid and cis-aconitic acid (assessed by metabolome analysis), associated significantly and positively with hepatic insulin sensitivity in NAFLD.
Project description:In order to explore the differentially expressed genes of E. coli B2 after citric acid induced antibiotic tolerance, we artificially induced the antibiotic tolerance of E. coli O157: H7 and verified its phenotype.
Project description:The goal of the study is to use Next generation sequencing (RNA-seq) and 13C based flux analysis to study the underlying regulation of citric acid metabolism in mixed culture fermentation (glucose and glycerl) of Yarrowia lipolytica. We sequenced the RNA from 4 different samples in the mixed culture (glucose and glycerol) under oxygen excess and limited conditions with 2 replicates each . Transcriptional profiles showed that under oxygen limited conditions, due to deficient mitochondrial activity, citric acid is being consumed back after glycerol exhaustion eventhough glucose is present in excess. Transcriptome and fluxome profiles showed that glucose is mainly directed towards the Pentose phosphate pathway in the dual substrate fermentations.
Project description:In order to explore the differentially expressed genes of E. coli O157: H7 after citric acid induced antibiotic tolerance, we artificially induced the antibiotic tolerance of E. coli O157: H7 and verified its phenotype.