Search results for "REDUCTASE"
showing 10 items of 798 documents
DctA- and Dcu-independent transport of succinate in Escherichia coli : contribution of diffusion and of alternative carriers
2001
Quintuple mutants of Escherichia coli deficient in the C4-dicarboxylate carriers of aerobic and anaerobic metabolism (DctA, DcuA, DcuB, DcuC, and the DcuC homolog DcuD, or the citrate/succinate antiporter CitT) showed only poor growth on succinate (or other C4-dicarboxylates) under oxic conditions. At acidic pH (pH 6) the mutants regained aerobic growth on succinate, but not on fumarate. Succinate uptake by the mutants could not be saturated at physiological succinate concentrations (≤5 mM), in contrast to the wild-type, which had a K m for succinate of 50 µM and a V max of 35 U/g dry weight at pH 6. At high substrate concentrations, the mutants showed transport activities (32 U/g dry weigh…
The Fumarate/Succinate Antiporter DcuB of Escherichia coli Is a Bifunctional Protein with Sites for Regulation of DcuS-dependent Gene Expression
2008
DcuB of Escherichia coli catalyzes C4-dicarboxylate/succinate antiport during growth by fumarate respiration. The expression of genes of fumarate respiration, including the genes for DcuB (dcuB) and fumarate reductase (frdABCD) is transcriptionally activated by C4-dicarboxylates via the DcuS-DcuR two-component system, comprising the sensor kinase DcuS, which contains a periplasmic sensing domain for C4-dicarboxylates. Deletion or inactivation of dcuB caused constitutive expression of DcuS-regulated genes in the absence of C4-dicarboxylates. The effect was specific for DcuB and not observed after inactivation of the homologous DcuA or the more distantly related DcuC transporter. Random and s…
Antisense lipoprotein[a] therapy: State-of-the-art and future perspectives
2020
Several lines of evidence now attest that lipoprotein[a] (Lp[a]) is a significant risk factor for many cardiovascular disorders. This enigmatic lipoprotein, composed of a single copy of apolipoprotein B (apoB) and apolipoprotein[a] (apo [a]), expresses peculiar metabolism, virtually independent from lifestyle interventions. Several therapeutic options have hence been proposed for lowering elevated Lp[a] values, with or without concomitant effect on low density lipoprotein (LDL) particles, mostly encompassing statins, ezetimibe, nicotinic acid, lipoprotein apheresis, and anti-PCSK9 monoclonal antibodies. Since all these medical treatments have some technical and clinical drawbacks, a novel s…
Influence of microsomal triglyceride transfer protein promoter polymorphism -493 GT on fasting plasma triglyceride values and interaction with treatm…
2005
Familial hypercholesterolaemia (FH) is an autosomal dominant disease characterized by elevated levels of low-density lipoprotein-cholesterol (LDL-C). Phenotypic expression is highly variable, being influenced by diet, age, gender, body mass index, apolipoprotein E genotype and type of LDL-receptor gene mutation. Microsomal triglyceride (TG) transfer protein (MTP) is a protein involved in lipid metabolism. Polymorphism MTP -493 GT has been shown to modulate lipid levels in several populations. To analyse the effect of this polymorphism in the lipid phenotype expression of FH and treatment response, we studied a sample of 222 Spanish FH patients, of whom 147 were studied before and after trea…
Gene-diet interaction in plasma lipid response to plant sterols and stanols: A review of clinical trials
2021
Abstract Plant sterols and stanols (PS) are well known for their cholesterol-lowering effect by reducing intestinal absorption of cholesterol. However, genetic factors modulate the low-density lipoprotein cholesterol (LDL-C) response to PS therapy. This review examines clinical trials evaluating the impact of the main genes associated with response of plasma lipid concentrations to PS intake: APOE, CYP7A1, ABCG5/G8, NPC1L1, CETP, APOA4/A5, SCARBI, HMGCR, PPARα, LIPC, MTHFR and LPA. Evidence indicates that carriers of mutant allele of the CYP7A1 c. −204 A > C variant experience a greater plasma cholesterol reduction after PS intake, although there is discrepancy for the rest of genetic varia…
Cholesterol in Alzheimer’s Disease and other Amyloidogenic Disorders
2010
The complex association of cholesterol metabolism and Alzheimer’s disease is presented in depth, including the possible benefits to be gained from cholesterol-lowering statin therapy. Then follows a survey of the role of neuronal membrane cholesterol in Aβ pore formation and Aβ fibrillogenesis, together with the link with membrane raft domains and gangliosides. The contribution of structural studies to Aβ fibrillogenesis, using TEM and AFM, is given some emphasis. The role of apolipoprotein E and its isoforms, in particular ApoE4, in cholesterol and Aβ binding is presented, in relation to genetic risk factors for Alzheimer’s disease. Increasing evidence suggests that cholesterol oxidation p…
Involvement of acyl coenzyme A oxidase isozymes in biotransformation of methyl ricinoleate into gamma-decalactone by Yarrowia lipolytica.
2000
ABSTRACT We reported previously on the function of acyl coenzyme A (acyl-CoA) oxidase isozymes in the yeast Yarrowia lipolytica by investigating strains disrupted in one or several acyl-CoA oxidase-encoding genes ( POX1 through POX5 ) (H. Wang et al., J. Bacteriol. 181:5140–5148, 1999). Here, these mutants were studied for lactone production. Monodisrupted strains produced similar levels of lactone as the wild-type strain (50 mg/liter) except for Δ pox3 , which produced 220 mg of γ-decalactone per liter after 24 h. The Δ pox2 Δpox3 double-disrupted strain, although slightly affected in growth, produced about 150 mg of lactone per liter, indicating that Aox2p was not essential for the biotra…
Energetic coupling between plastids and mitochondria drives CO2 assimilation in diatoms.
2015
International audience; Diatoms are one of the most ecologically successful classes of photosynthetic marine eukaryotes in the contemporary oceans. Over the past 30 million years, they have helped to moderate Earth's climate by absorbing carbon dioxide from the atmosphere, sequestering it via the biological carbon pump and ultimately burying organic carbon in the lithosphere. The proportion of planetary primary production by diatoms in the modern oceans is roughly equivalent to that of terrestrial rainforests. In photosynthesis, the efficient conversion of carbon dioxide into organic matter requires a tight control of the ATP/NADPH ratio which, in other photosynthetic organisms, relies prin…
Proton coupled electron transfer of ubiquinone Q2 incorporated in a self-assembled monolayer.
2011
We present a complete study of the reduction of ubiquinone Q(2) (UQ(2)) in simpler aqueous medium, over a pH range of 2.5 to 12.5. The short isoprenic chain ubiquinones (UQ(2)) were incorporated in a self-assembled monolayer. Under these conditions, the global 2e(-) electrochemical reaction can be described on the basis of a nine-member square scheme. The thermodynamic constants of the system were determined. The global 2e(-) process is controlled by the uptake of the second electron. The elementary electrochemical rate constants obtained by fitting of the experimental rate constant were k(s4) = 1.5 s(-1) for QH˙(+)(2)↔ QH(2), k(s5) = 1.5 s(-1) for QH˙↔ QH(-) and k(s6) = 1 s(-1) for Q˙(-)↔ …
Study of oligogalacturonides-triggered Nitric Oxide (NO) production provokes new questioning about the origin of NO biosynthesis in plants
2014
Addendum to: Rasul S, Dubreuil-Maurizi C, Lamotte O, Koen E, Poinssot B, Alcaraz G, et al. Nitric oxide production mediates oligogalacturonide-triggered immunity and resistance to Botrytis cinerea in Arabidopsis thaliana. Plant Cell Environ 2012; PMID:22394204; http://dx.doi. org/10.1111/j.1365-3040.2012.02505.x.; International audience; We investigated the production and function of nitric oxide (NO) in Arabidopsis thaliana leaf discs as well as whole plants elicited by oligogalacturonides (OGs). Using genetic, biochemical and pharmacological approaches, we provided evidence that OGs induced a Nitrate Reductase (NR)-dependent NO production together with an increased NR activity and NR tran…