Search results for "hydrogenase"
showing 10 items of 575 documents
Pyruvate dehydrogenase specific T cells in primary biliary cirrhosis show restricted antigen recognition sites
2002
: Background/Aims: The aim was to characterise the antigen recognition sites of the variable T cell receptor α-chain (TCRAV) and β-chain (TCRBV) of T cells specific to the pyruvate dehydrogenase (PDC) in primary biliary cirrhosis. Methods: In 21 PDC-specific T cell clones isolated from five patients we analysed TCRAV and TCRBV usage by RT-PCR and sequenced the CDR3 regions. Results: Preferential expression of the TCR elements BV6 (6 clones), BV12 (4 clones) and BV1 (3 clones), and frequent usage of the joining elements JB2.3 and JB2.1 were seen. Analysis of the α chain revealed rearrangement of AV2 in 7 clones (35%) and AV7 in 3 clones, however, distribution of the joining elements was het…
How hexoses and inhibitors influence the malate transport system in Zygosaccharomyces bailii
1988
When grown in fructose or glucose the cells of Zygosaccharomyces bailii were physiologically different. Only the glucose grown cells (glucose cells) possessed an additional transport system for glucose and malate. Experiments with transport mutants had lead to the assumption that malate and glucose were transported by one carrier, but further experiments proved the existence of two separate carrier systems. Glucose was taken up by carriers with high and low affinity. Malate was only transported by an uptake system and it was not liberated by starved malate-loaded cells, probably due to the low affinity of the intracellular anion to the carrier. The uptake of malate was inhibited by fructose…
Prehibernation and hibernation effects on the D-3-hydroxybutyrate dehydrogenase of the heavy and light mitochondria from liver jerboa (Jaculus orient…
2007
The D-3-hydroxybutyrate dehydrogenase (BDH) (EC 1.1.1.30) from liver jerboa (Jaculus orientalis), a ketone body converting enzyme in mitochondria, in two populations of mitochondria (heavy and light) has been studied in different jerboa states (euthermic, prehibernating and hibernating). The results reveal: (1) important variations between states in terms of ketones bodies, glucose and lipid levels; (2) significant differences between the BDH of the two mitochondrial populations in term of protein expression and kinetic properties. These results suggest that BDH leads an important conformational change depending on the physiological state of jerboa. This BDH structural change could be the c…
Peroxisomal changes during hiberation of jerboa (Jaculus orientalis)
1998
As a member of the order of Rodentia, jerboa (Jaculus orientalis) is a natural deep hibernator and lives in subdesert highland in many parts of the world, including Morocco. Its small size (adult body weight ∼100 g), availability in the wild, tolerance to laboratory conditions, and some unique peroxisomal properties make it a suitable research subject for exploring peroxisome biogenesis under prehibernating and hibernating states. During 3 w, animals referred to as the prehibernator group were exposed to cold temperature (5 to 7°C) with food ad libitum. Part of the prehibernator group entered deep hibernation 24 to 48 h after starvation. Animals were sacrificed 4 and 6 d after starting hibe…
Peroxisome proliferator-activated receptors as regulators of lipid metabolism; tissue differential expression in adipose tissues during cold acclimat…
2004
Brown (BAT) and white (WAT) adipose tissues play a key role in the body energy balance orchestrated by the central nervous system. Hibernators have developed a seasonal obesity to respond to inhospitable environment. Jerboa is one of the deep hibernator originated from sub-desert highlands. Thus, this animal represents an excellent model to study cold adaptation mechanism. We report that the adipogenic factor PPARgamma exhibits a differential expression between BAT and WAT at mRNA level. A specific induction was only seen in WAT of pre-hibernating jerboa. Interestingly, PPAR beta/delta is specifically induced in BAT and brain of pre-hibernating jerboa, highlighting for the first time the po…
Fumarate regulation of gene expression in Escherichia coli by the DcuSR (dcuSR genes) two-component regulatory system.
1998
ABSTRACT In Escherichia coli the genes encoding the anaerobic fumarate respiratory system are transcriptionally regulated by C 4 -dicarboxylates. The regulation is effected by a two-component regulatory system, DcuSR, consisting of a sensory histidine kinase (DcuS) and a response regulator (DcuR). DcuS and DcuR are encoded by the dcuSR genes (previously yjdHG ) at 93.7 min on the calculated E. coli map. Inactivation of the dcuR and dcuS genes caused the loss of C 4 -dicarboxylate-stimulated synthesis of fumarate reductase ( frdABCD genes) and of the anaerobic fumarate-succinate antiporter DcuB ( dcuB gene). DcuS is predicted to contain a large periplasmic domain as the supposed site for C 4…
Triazole-Containing [FeFe] Hydrogenase Mimics: Synthesis and Electrocatalytic Behavior
2019
Through a Cu-catalyzed Huisgen cycloaddition between terminal alkynes and azides (CuAAC) reaction, azide [(μ-SCH2)2N(4-N3C6H4)Fe2(CO)6] has demonstrated to be a robust and versatile reagent able to...
Application of 61Ni Mössbauer spectroscopy to chemical problems
1996
Using the possibility to produce 61Co sources at the MAinz MIcrotron, 61Ni Mossbauer spectroscopy was applied to different kinds of chemical problems. Measurements of isomer shifts and V zz values in some common compounds and compounds with unusual chemical bonding for comparison with band structure calculations, measurement of 61Ni Mossbauer parameters in model compounds for hydrogenase and dehydrogenase with an active [NiS4] centre, and study of novel binary NiF3 compounds at helium temperature are presented.
Fumarate respiration of Wolinella succinogenes: enzymology, energetics and coupling mechanism.
2002
Wolinella succinogenes performs oxidative phosphorylation with fumarate instead of O2 as terminal electron acceptor and H2 or formate as electron donors. Fumarate reduction by these donors ('fumarate respiration') is catalyzed by an electron transport chain in the bacterial membrane, and is coupled to the generation of an electrochemical proton potential (Deltap) across the bacterial membrane. The experimental evidence concerning the electron transport and its coupling to Deltap generation is reviewed in this article. The electron transport chain consists of fumarate reductase, menaquinone (MK) and either hydrogenase or formate dehydrogenase. Measurements indicate that the Deltap is generat…
Enzymes for the NADPH-dependent reduction of dihydroxyacetone and D-glyceraldehyde and L-glyceraldehyde in the mould Hypocrea jecorina
2006
The mould Hypocrea jecorina (Trichoderma reesei) has two genes coding for enzymes with high similarity to the NADP-dependent glycerol dehydrogenase. These genes, called gld1 and gld2, were cloned and expressed in a heterologous host. The encoded proteins were purified and their kinetic properties characterized. GLD1 catalyses the conversion of d-glyceraldehyde and l-glyceraldehyde to glycerol, whereas GLD2 catalyses the conversion of dihydroxyacetone to glycerol. Both enzymes are specific for NADPH as a cofactor. The properties of GLD2 are similar to those of the previously described NADP-dependent glycerol-2- dehydrogenases (EC 1.1.1.156) purified from different mould species. It is a reve…