Project description:In this study, we have explored the impact of ascorbic acid on the transcriptome of Streptococcus pneumoniae D39. The expression of several genes and operons, including the ula operon (which has been previously shown to be involved in ascorbic acid utilization), the AdcR regulon (which has been previously shown to be involved in zinc transport and virulence) and a PTS operon (which we denote here as ula2 operon) were altered in the presence of ascorbic acid. The ula2 operon consists of five genes, including the transcriptional activator ulaR2. Our β-galactosidase assay data and transcriptome comparison of the ulaR2 mutant with the wild-type demonstrated that the transcriptional activator UlaR2 in the presence of ascorbic acid activates the expression of the ula2 operon. We further predict a 16-bp regulatory site (5’-ATATTGTGCTCAAATA-3’) for UlaR2 binding in the Pula2. Furthermore, we have explored the effect of ascorbic acid on the expression of the AdcR regulon. Our ICP-MS analysis showed that addition of ascorbic acid to the medium causes zinc starvation in the cell that leads to the activation of the AdcR regulon. This SuperSeries is composed of the SubSeries listed below.
Project description:In this study, we have explored the impact of ascorbic acid on the transcriptome of Streptococcus pneumoniae D39. The expression of several genes and operons, including the ula operon (which has been previously shown to be involved in ascorbic acid utilization), the AdcR regulon (which has been previously shown to be involved in zinc transport and virulence) and a PTS operon (which we denote here as ula2 operon) were altered in the presence of ascorbic acid. The ula2 operon consists of five genes, including the transcriptional activator ulaR2. Our β-galactosidase assay data and transcriptome comparison of the ulaR2 mutant with the wild-type demonstrated that the transcriptional activator UlaR2 in the presence of ascorbic acid activates the expression of the ula2 operon. We further predict a 16-bp regulatory site (5'-ATATTGTGCTCAAATA-3') for UlaR2 in the Pula2. Furthermore, we have explored the effect of ascorbic acid on the expression of the AdcR regulon. Our ICP-MS analysis showed that addition of ascorbic acid to the medium causes zinc starvation in the cell which leads to the activation of the AdcR regulon.
Project description:In addition to the role of antioxidant, ascorbic acid (reducing Vitamin C) is an important cofactor for Fe2+ and α-ketoglutarate (α-KG) dependent dioxygenases (Fe2+/α-KGDDs) that comprise many diverse enzymes, including collagen prolyl hydroxylases, jmjC (Jumonji C) domain containing histone demethylases, Ten-eleven translocation (TET) 5-methyl cytosine (5mC) dioxygenases, and N6-methyl adenosine (m6A) demethylase FTO and ALKBH5. Ascorbic acid was reported to induce global epigenetic reprogramming. Here we optimized the library construction flow chart of single-stranded DNA profiling method KAS-seq and utilized KAS-seq to profile transient chromatin states changes upon ascorbic acid treatment for 10 min. We identified several critical pathways affected by ascorbic acid treatment, providing some clues for explaining the reported positive impact of anti-cancer, anti-depression, and anti-obesity for taking ascorbic acid.
Project description:Transcriptome comparison of the Streptococcus pneumoniae D39 wild-type grown in M17 medium to grown in M17 medium + 10mM ascorbic acid (AM17).
Project description:Ascorbic acid has been reported to stimulate DNA iterative oxidase TET enzymes, Jumonji C-domain-containinghistone demethylase and potentially RNA m6A demethylase FTO and ALKBH5 as a cofactor. Although ascorbic acid has been widely investigated in reprogramming DNA and histone methylation status in vitro, in cell lines and mouse models, its specific role in the catalytic cycle of dioxygenases remains enigmatic. Here we systematically investigated the stimulation of ascorbic towards TET2, ALKBH3, histone demethylases and FTO. We find that ascorbic acid reprograms epitranscrip-tome by erasing the hypermethylated m6A sites. Biochemistry and Electron spin resonance (ESR) assays demonstrate that ascorbic acid enters the active pocket of dioxygenases, reduces Fe (III), either incorporated upon protein synthesis or generated upon rebounding the hydroxyl radical during oxidation, into Fe (II). Finally, we propose a new model for the catalytic cycle of dioxygenases by adding in the essential dynamic cofactor, ascorbic acid. Ascorbic acid refreshes and regenerates inactive dioxygenase through recycling Fe (III) into Fe (II) in a dynamic “hit-and-run” manner.
Project description:Ascorbic acid has been reported to stimulate DNA iterative oxidase TET enzymes, Jumonji C-domain-containinghistone demethylase and potentially RNA m6A demethylase FTO and ALKBH5 as a cofactor. Although ascorbic acid has been widely investigated in reprogramming DNA and histone methylation status in vitro, in cell lines and mouse models, its specific role in the catalytic cycle of dioxygenases remains enigmatic. Here we systematically investigated the stimulation of ascorbic towards TET2, ALKBH3, histone demethylases and FTO. We find that ascorbic acid reprograms epitranscrip-tome by erasing the hypermethylated m6A sites. Biochemistry and Electron spin resonance (ESR) assays demonstrate that ascorbic acid enters the active pocket of dioxygenases, reduces Fe (III), either incorporated upon protein synthesis or generated upon rebounding the hydroxyl radical during oxidation, into Fe (II). Finally, we propose a new model for the catalytic cycle of dioxygenases by adding in the essential dynamic cofactor, ascorbic acid. Ascorbic acid refreshes and regenerates inactive dioxygenase through recycling Fe (III) into Fe (II) in a dynamic “hit-and-run” manner.
Project description:The assessment of toxicity about patulin using yeast gene expression comparison analysis. Yeast BY4743 derivative SOD1 mutant was used for this study. Ascorbic acid was used to evaluate the anti-toxic effect to patulin. Keywords: stress response Four series of samples were compared with each by ANOVA analysis. Each strain was grown in YPD medium, and they were also incubated with 25 ppm of patulin and 10 mM ascorbic acid.
Project description:Endoplasmic reticulum (ER) thiol oxidases initiate a disulfide relay to oxidatively-fold secreted proteins. We found that combined loss-of-function mutations in genes encoding the ER thiol oxidases ERO1alpha, ERO1beta and PRDX4, compromised the extracellular matrix in mice and interfered with the intracellular maturation of procollagen. These severe abnormalities were associated with an unexpectedly-modest delay in disulfide bond formation in secreted proteins but a profound, five-fold lower procollagen 4 hydroxyproline content and enhanced cysteinyl sulfenic acid modification of ER proteins. Tissue ascorbic acid content was lower in mutant mice and ascorbic acid supplementation improved procollagen maturation and lowered sulfenic acid content, in vivo. In vitro, the presence of a sulfenic acid donor accelerated the oxidative inactivation of ascorbate by an H2O2 generating system. Compromised ER disulfide relay thus exposes protein thiols to competing oxidation to sulfenic acid, resulting in depletion of ascorbic acid, impaired procollagen proline 4-hydroxylation and a non-canonical form of scurvy.