WorldWideScience

Sample records for dehydrogenase activity electronic

  1. Low temperature electron beam irradiation effects on the lactate dehydrogenase activity

    International Nuclear Information System (INIS)

    Catana, D.; Hategan, Alina; Oproiu, C.; Popescu, Alina; Hategan, Dora; Morariu, V. V.

    1998-01-01

    The direct and indirect effects of 5 MeV electron beam irradiation in the range 0-400 Gy at 20 deg. C, -3 deg. C and -196 deg. C on the global enzymatic activity of lactate dehydrogenase (LDH) have been studied. Our results showed a monoexponential decrease in the enzymatic activity of irradiated LDH at all irradiation temperatures independently of direct or indirect action of radiation. The temperature gradient used to lower the temperature of the samples to -196 deg. C drastically influences the results. Our data suggest that freeze-thawing in two steps down to -196 deg. C make LDH insensitive to irradiation, while one step freeze-thawing procedure results in a gradual activity loss with increasing dose irradiation. This data can be interpreted in terms of different conformational changes during the particular freeze-thawing process. (authors)

  2. Constitutive NADPH-dependent electron transferase activity of the Nox4 dehydrogenase domain.

    Science.gov (United States)

    Nisimoto, Yukio; Jackson, Heather M; Ogawa, Hisamitsu; Kawahara, Tsukasa; Lambeth, J David

    2010-03-23

    NADPH oxidase 4 (Nox4) is constitutively active, while Nox2 requires the cytosolic regulatory subunits p47(phox) and p67(phox) and activated Rac with activation by phorbol 12-myristate 13-acetate (PMA). This study was undertaken to identify the domain on Nox4 that confers constitutive activity. Lysates from Nox4-expressing cells exhibited constitutive NADPH- but not NADH-dependent hydrogen peroxide production with a K(m) for NADPH of 55 +/- 10 microM. The concentration of Nox4 in cell lysates was estimated using Western blotting and allowed calculation of a turnover of approximately 200 mol of H(2)O(2) min(-1) (mol of Nox4)(-1). A chimeric protein (Nox2/4) consisting of the Nox2 transmembrane (TM) domain and the Nox4 dehydrogenase (DH) domain showed H(2)O(2) production in the absence of cytosolic regulatory subunits. In contrast, chimera Nox4/2, consisting of the Nox4 TM and Nox2 DH domains, exhibited PMA-dependent activation that required coexpression of regulatory subunits. Nox DH domains from several Nox isoforms were purified and evaluated for their electron transferase activities. Nox1 DH, Nox2 DH, and Nox5 DH domains exhibited barely detectable activities toward artificial electron acceptors, while the Nox4 DH domain exhibited significant rates of reduction of cytochrome c (160 min(-1), largely superoxide dismutase-independent), ferricyanide (470 min(-1)), and other electron acceptors (artificial dyes and cytochrome b(5)). Rates were similar to those observed for H(2)O(2) production by the Nox4 holoenzyme in cell lysates. The activity required added FAD and was seen with NADPH but not NADH. These results indicate that the Nox4 DH domain exists in an intrinsically activated state and that electron transfer from NADPH to FAD is likely to be rate-limiting in the NADPH-dependent reduction of oxygen by holo-Nox4.

  3. Constitutive NADPH-Dependent Electron Transferase Activity of the Nox4 Dehydrogenase Domain?

    OpenAIRE

    Nisimoto, Yukio; Jackson, Heather M.; Ogawa, Hisamitsu; Kawahara, Tsukasa; Lambeth, J. David

    2010-01-01

    NADPH oxidase 4 (Nox4) is constitutively active, while Nox2 requires the cytosolic regulatory subunits p47 phox and p67 phox and activated Rac with activation by phorbol 12-myristate 13-acetate (PMA). This study was undertaken to identify the domain on Nox4 that confers constitutive activity. Lysates from Nox4-expressing cells exhibited constitutive NADPH- but not NADH-dependent hydrogen peroxide production with a K m for NADPH of 55 ? 10 ?M. The concentration of Nox4 in cell lysates was esti...

  4. INFLUENCE OF SELECTED PHARMACEUTICALS ON ACTIVATED SLUDGE DEHYDROGENASE ACTIVITY

    Directory of Open Access Journals (Sweden)

    Agnieszka Tomska

    2016-06-01

    The aim of this work was to evaluate the effect of selected antibiotics - sulfanilamide and erythromycin on activated sludge dehydrogenase activity with use of trifenyltetrazolinum chloride (TTC test. Dehydrogenases activity is an indicator of biochemical activity of microorganisms present in activated sludge or the ability to degrade organic compounds in waste water. TTC test is particularly useful for the regularity of the course of treatment, in which the presence of inhibitors of biochemical reactions and toxic compounds are present. It was observed that the dehydrogenase activity decreases with the increase of a antibiotics concentration. The lowest value of the dehydrogenase activity equal to 32.4 μmol TF / gMLSS obtained at sulfanilamide concentration 150mg / l. For this sample, an inhibition of dehydrogenase activity was 31%.

  5. Study on the triphenyl tetrazolium chloride– dehydrogenase activity ...

    African Journals Online (AJOL)

    A quick analysis of the sludge activity method based on triphenyltetrazolium chloride-dehydrogenase activity (TTC-DHA) was developed to change the rule and status of the biological activity of the activated sludge in tomato paste wastewater treatment. The results indicate that dehydrogenase activity (DHA) can effectively ...

  6. Effects of accelerated electrons and microwaves on frozen enzyme lactate dehydrogenase

    International Nuclear Information System (INIS)

    Hategan, A.; Martin, D.; Popescu, L.M.; Butan, C.

    2000-01-01

    Results on the influence of 6 MeV electron beam irradiation and 2.45 GHz 565 W microwaves as well as the effects of the combined electron and microwave irradiation, at - 21 deg. C, on enzyme lactate dehydrogenase are presented. The microwave irradiated macromolecules exhibited a non-linear behaviour (successive activation and inactivation of the enzyme molecules) suggesting the major influence of the nonthermal component of microwave radiation. The combined electron and microwave irradiation lead to a similar decrease of the activity as the electron beam irradiation, the microwave influence being apparently insignificant in the dose, power and time ranges used. Radiation target analysis of the enzymatic decrease due to electron irradiation indicated very large aggregation of the enzyme molecules. Our data suggest that radiation target analysis is not suitable to measure the molecular mass of lactate dehydrogenase, when irradiating frozen enzyme suspensions. (authors)

  7. High energy electron beam inactivation of lactate dehydrogenase suspended in different aqueous media

    International Nuclear Information System (INIS)

    Hategan, A.; Oproiu, C.; Popescu, A.; Hategan, D.; Morariu, V.V.

    1998-01-01

    The direct and indirect effects of 5 MeV electron beam irradiation at various low temperatures, as well as the influence of the presence or absence of deuterium ions in the suspending medium of the enzyme, on the global enzymatic activity of lactate dehydrogenase have been studied. Frozen lactate dehydrogenase suspensions at 0 degC, -3 degC and -196 degC temperatures have been irradiated with the 5 MeV electron beam of a linear accelerator in the dose range 0-400 Gy. Liquid lactate dehydrogenase suspensions in D 2 O (99.98 %) and ultrapure water (17 ppm) at 0 degC have been irradiated in the dose range 0 -15 Gy. An exponential decrease was found in the enzymatic activity of irradiated lactate dehydrogenase, at all irradiation temperatures. The drastic decrease in the activity for the enzyme irradiated at 0 degC (total inhibition for a final dose of 100 Gy) indicate that at this temperature the indirect effects of radiation (due to the water radicals induced by radiation in the samples) are predominant. At -3 degC irradiation temperature the indirect effects of radiation are smaller but still present (a total decrease in the enzymatic activity for a dose of 250 Gy), while at -196 degC they are orders of magnitude reduced and the decrease in the enzymatic activity is due almost to the direct interaction of electrons with the macromolecules (70 % for a dose of 400 Gy)

  8. Toxicity of Nitrification Inhibitors on Dehydrogenase Activity in Soils

    OpenAIRE

    Ferisman Tindaon; Gero Benckiser; Johannes C. G. Ottow

    2011-01-01

    The objective of this research was to determine the effects of nitrification inhibitors (NIs) such as 3,4-dimethylpyrazolephosphate=DMPP, 4-Chlor-methylpyrazole phosphate=ClMPP and dicyandiamide,DCD) which might be expected to inhibit microbial activity, on dehydrogenase activity (DRA),in three different soils in laboratory conditions. Dehydrogenase activity were assessed via reduction of 2-p-Iodophenyl-3-p-nitrophenyl-5-phenyltetrazoliumchloride (INT). The toxicity and dose response curve of...

  9. Construction of Mutant Glucose Oxidases with Increased Dye-Mediated Dehydrogenase Activity

    Science.gov (United States)

    Horaguchi, Yohei; Saito, Shoko; Kojima, Katsuhiro; Tsugawa, Wakako; Ferri, Stefano; Sode, Koji

    2012-01-01

    Mutagenesis studies on glucose oxidases (GOxs) were conducted to construct GOxs with reduced oxidase activity and increased dehydrogenase activity. We focused on two representative GOxs, of which crystal structures have already been reported—Penicillium amagasakiense GOx (PDB ID; 1gpe) and Aspergillus niger GOx (PDB ID; 1cf3). We constructed oxygen-interacting structural models for GOxs, and predicted the residues responsible for oxidative half reaction with oxygen on the basis of the crystal structure of cholesterol oxidase as well as on the fact that both enzymes are members of the glucose/methanol/choline (GMC) oxidoreductase family. Rational amino acid substitution resulted in the construction of an engineered GOx with drastically decreased oxidase activity and increased dehydrogenase activity, which was higher than that of the wild-type enzyme. As a result, the dehydrogenase/oxidase ratio of the engineered enzyme was more than 11-fold greater than that of the wild-type enzyme. These results indicate that alteration of the dehydrogenase/oxidase activity ratio of GOxs is possible by introducing a mutation into the putative functional residues responsible for oxidative half reaction with oxygen of these enzymes, resulting in a further increased dehydrogenase activity. This is the first study reporting the alteration of GOx electron acceptor preference from oxygen to an artificial electron acceptor. PMID:23203056

  10. Construction of Mutant Glucose Oxidases with Increased Dye-Mediated Dehydrogenase Activity

    Directory of Open Access Journals (Sweden)

    Koji Sode

    2012-11-01

    Full Text Available Mutagenesis studies on glucose oxidases (GOxs were conducted to construct GOxs with reduced oxidase activity and increased dehydrogenase activity. We focused on two representative GOxs, of which crystal structures have already been reported—Penicillium amagasakiense GOx (PDB ID; 1gpe and Aspergillus niger GOx (PDB ID; 1cf3. We constructed oxygen-interacting structural models for GOxs, and predicted the residues responsible for oxidative half reaction with oxygen on the basis of the crystal structure of cholesterol oxidase as well as on the fact that both enzymes are members of the glucose/methanol/choline (GMC oxidoreductase family. Rational amino acid substitution resulted in the construction of an engineered GOx with drastically decreased oxidase activity and increased dehydrogenase activity, which was higher than that of the wild-type enzyme. As a result, the dehydrogenase/oxidase ratio of the engineered enzyme was more than 11-fold greater than that of the wild-type enzyme. These results indicate that alteration of the dehydrogenase/oxidase activity ratio of GOxs is possible by introducing a mutation into the putative functional residues responsible for oxidative half reaction with oxygen of these enzymes, resulting in a further increased dehydrogenase activity. This is the first study reporting the alteration of GOx electron acceptor preference from oxygen to an artificial electron acceptor.

  11. Construction of mutant glucose oxidases with increased dye-mediated dehydrogenase activity.

    Science.gov (United States)

    Horaguchi, Yohei; Saito, Shoko; Kojima, Katsuhiro; Tsugawa, Wakako; Ferri, Stefano; Sode, Koji

    2012-11-02

    Mutagenesis studies on glucose oxidases (GOxs) were conducted to construct GOxs with reduced oxidase activity and increased dehydrogenase activity. We focused on two representative GOxs, of which crystal structures have already been reported—Penicillium amagasakiense GOx (PDB ID; 1gpe) and Aspergillus niger GOx (PDB ID; 1cf3). We constructed oxygen-interacting structural models for GOxs, and predicted the residues responsible for oxidative half reaction with oxygen on the basis of the crystal structure of cholesterol oxidase as well as on the fact that both enzymes are members of the glucose/methanol/choline (GMC) oxidoreductase family. Rational amino acid substitution resulted in the construction of an engineered GOx with drastically decreased oxidase activity and increased dehydrogenase activity, which was higher than that of the wild-type enzyme. As a result, the dehydrogenase/oxidase ratio of the engineered enzyme was more than 11-fold greater than that of the wild-type enzyme. These results indicate that alteration of the dehydrogenase/oxidase activity ratio of GOxs is possible by introducing a mutation into the putative functional residues responsible for oxidative half reaction with oxygen of these enzymes, resulting in a further increased dehydrogenase activity. This is the first study reporting the alteration of GOx electron acceptor preference from oxygen to an artificial electron acceptor.

  12. Direct Electron Transfer of Dehydrogenases for Development of 3rd Generation Biosensors and Enzymatic Fuel Cells

    Directory of Open Access Journals (Sweden)

    Paolo Bollella

    2018-04-01

    Full Text Available Dehydrogenase based bioelectrocatalysis has been increasingly exploited in recent years in order to develop new bioelectrochemical devices, such as biosensors and biofuel cells, with improved performances. In some cases, dehydrogeases are able to directly exchange electrons with an appropriately designed electrode surface, without the need for an added redox mediator, allowing bioelectrocatalysis based on a direct electron transfer process. In this review we briefly describe the electron transfer mechanism of dehydrogenase enzymes and some of the characteristics required for bioelectrocatalysis reactions via a direct electron transfer mechanism. Special attention is given to cellobiose dehydrogenase and fructose dehydrogenase, which showed efficient direct electron transfer reactions. An overview of the most recent biosensors and biofuel cells based on the two dehydrogenases will be presented. The various strategies to prepare modified electrodes in order to improve the electron transfer properties of the device will be carefully investigated and all analytical parameters will be presented, discussed and compared.

  13. Discrimination of damages depending on the types of lactic dehydrogenase isozymes in electron beam irradiation

    International Nuclear Information System (INIS)

    Ohta, Akishige; Matsubayashi, Takashi; Liu Xiaolan; Takizawa, Haruki.

    1995-01-01

    Lactate dehydrogenase (EC 1.1.1.27,LDH) was a tetrameric molecule. The five different combinations of two different polypeptide chains can be readily identified by electrophoresis and ion-exchange chromatography. Injury patterns of LDH activity following electron-beam irradiation was investigated by assaying activities of three isozymes (pig heart LDH;M 4 , rabbit muscle LDH;H 4 , chicken heart LDH;M 3 H 1 ). Following results were obtained in the electron beam irradiation to three kinds of LDH isozymes: 1) Each isozyme has respective different reactivities to the electron beam irradiation. 2) Among the isozymes, M 4 enzyme was increased its enzymatic activity by the irradiations of low-level doses. 3) For the H 4 enzymes, an increasing phenomenon of -SH group was found in the low-level doses of electron beam irradiation. (author)

  14. Aminotransferase and glutamate dehydrogenase activities in lactobacilli and streptococci

    Directory of Open Access Journals (Sweden)

    Guillermo Hugo Peralta

    Full Text Available ABSTRACT Aminotransferases and glutamate dehydrogenase are two main types of enzymes involved in the initial steps of amino acid catabolism, which plays a key role in the cheese flavor development. In the present work, glutamate dehydrogenase and aminotransferase activities were screened in twenty one strains of lactic acid bacteria of dairy interest, either cheese-isolated or commercial starters, including fifteen mesophilic lactobacilli, four thermophilic lactobacilli, and two streptococci. The strains of Streptococcus thermophilus showed the highest glutamate dehydrogenase activity, which was significantly elevated compared with the lactobacilli. Aspartate aminotransferase prevailed in most strains tested, while the levels and specificity of other aminotransferases were highly strain- and species-dependent. The knowledge of enzymatic profiles of these starter and cheese-isolated cultures is helpful in proposing appropriate combinations of strains for improved or increased cheese flavor.

  15. Serum creatine kinase and lactate dehydrogenase activities in ...

    African Journals Online (AJOL)

    ... in thyroid function are common endocrine disorders affecting 5-10% of individuals over ... Key words: Hyperthyroidism, hypothyroidism, lactate dehydrogenase, serum creatine kinase ... individuals depends on age, race, lean body mass and physical activity. ... measured by radioimmunoassay on AXSYM System (Abbott.

  16. High-fat diet enhanced retinal dehydrogenase activity, but suppressed retinol dehydrogenase activity in liver of rats

    Directory of Open Access Journals (Sweden)

    Mian Zhang

    2015-04-01

    Full Text Available Evidence has shown that hyperlipidemia is associated with retinoid dyshomeostasis. In liver, retinol is mainly oxidized to retinal by retinol dehydrogenases (RDHs and alcohol dehydrogenases (ADHs, further converted to retinoic acid by retinal dehydrogenases (RALDHs. The aim of this study was to investigate whether high-fat diet (HFD induced hyperlipidemia affected activity and expression of hepatic ADHs/RDHs and RALDHs in rats. Results showed that retinol levels in liver, kidney and adipose tissue of HFD rats were significantly increased, while plasma retinol and hepatic retinal levels were markedly decreased. HFD rats exhibited significantly downregulated hepatic ADHs/RDHs activity and Adh1, Rdh10 and Dhrs9 expression. Oppositely, hepatic RALDHs activity and Raldh1 expression were upregulated in HFD rats. In HepG2 cells, treatment of HFD rat serum inhibited ADHs/RDHs activity and induced RALDHs activity. Among the tested abnormally altered components in HFD rat serum, cholesterol reduced ADHs/RDHs activity and RDH10 expression, while induced RALDHs activity and RALDH1 expression in HepG2 cells. Contrary to the effect of cholesterol, cholesterol-lowering agent pravastatin upregulated ADHs/RDHs activity and RDH10 expression, while suppressed RALDHs activity and RALDH1 expression. In conclusion, hyperlipidemia oppositely altered activity and expression of hepatic ADHs/RDHs and RALDHs, which is partially due to the elevated cholesterol levels.

  17. Influence of thorax irradiation on lactic dehydrogenase isoenzyme activity

    International Nuclear Information System (INIS)

    Valle, C.; Munnich, A.; Pasquier, C.

    The right hemi-thorax of rats was irradiated with 1200 and 3000 rads ( 60 Co) and blood samples were taken sequentially. The five lactic dehydrogenase (LDH) isoenzymes which have proved to be useful as biochemical indicators of acute pulmonary injury in other experimental animals (dogs), were assayed, after irradiation, as a function of time and as a functon of dose. There was no significant change in LDH isoenzyme activities after lung irradiation in rats [fr

  18. Catalytic properties of thermophilic lactate dehydrogenase and halophilic malate dehydrogenase at high temperature and low water activity.

    Science.gov (United States)

    Hecht, K; Wrba, A; Jaenicke, R

    1989-07-15

    Thermophilic lactate dehydrogenases from Thermotoga maritima and Bacillus stearothermophilus are stable up to temperature limits close to the optimum growth temperature of their parent organisms. Their catalytic properties are anomalous in that Km shows a drastic increase with increasing temperature. At low temperatures, the effect levels off. Extreme halophilic malate dehydrogenase from Halobacterium marismortui exhibits a similar anomaly. Increasing salt concentration (NaCl) leads to an optimum curve for Km, oxaloacctate while Km, NADH remains constant. Previous claims that the activity of halophilic malate dehydrogenase shows a maximum at 1.25 M NaCl are caused by limiting substrate concentration; at substrate saturation, specific activity of halophilic malate dehydrogenase reaches a constant value at ionic strengths I greater than or equal to 1 M. Non-halophilic (mitochondrial) malate dehydrogenase shows Km characteristics similar to those observed for the halophilic enzyme. The drastic decrease in specific activity of the mitochondrial enzyme at elevated salt concentrations is caused by the salt-induced increase in rigidity of the enzyme, rather than gross structural changes.

  19. Bimolecular Rate Constants for FAD-Dependent Glucose Dehydrogenase from Aspergillus terreus and Organic Electron Acceptors.

    Science.gov (United States)

    Tsuruoka, Nozomu; Sadakane, Takuya; Hayashi, Rika; Tsujimura, Seiya

    2017-03-10

    The flavin adenine dinucleotide-dependent glucose dehydrogenase (FAD-GDH) from Aspergillus species require suitable redox mediators to transfer electrons from the enzyme to the electrode surface for the application of bioelectrical devices. Although several mediators for FAD-GDH are already in use, they are still far from optimum in view of potential, kinetics, sustainability, and cost-effectiveness. Herein, we investigated the efficiency of various phenothiazines and quinones in the electrochemical oxidation of FAD-GDH from Aspergillus terreus . At pH 7.0, the logarithm of the bimolecular oxidation rate constants appeared to depend on the redox potentials of all the mediators tested. Notably, the rate constant of each molecule for FAD-GDH was approximately 2.5 orders of magnitude higher than that for glucose oxidase from Aspergillus sp. The results suggest that the electron transfer kinetics is mainly determined by the formal potential of the mediator, the driving force of electron transfer, and the electron transfer distance between the redox active site of the mediator and the FAD, affected by the steric or chemical interactions. Higher k ₂ values were found for ortho-quinones than for para-quinones in the reactions with FAD-GDH and glucose oxidase, which was likely due to less steric hindrance in the active site in the case of the ortho-quinones.

  20. Bimolecular Rate Constants for FAD-Dependent Glucose Dehydrogenase from Aspergillus terreus and Organic Electron Acceptors

    Directory of Open Access Journals (Sweden)

    Nozomu Tsuruoka

    2017-03-01

    Full Text Available The flavin adenine dinucleotide-dependent glucose dehydrogenase (FAD-GDH from Aspergillus species require suitable redox mediators to transfer electrons from the enzyme to the electrode surface for the application of bioelectrical devices. Although several mediators for FAD-GDH are already in use, they are still far from optimum in view of potential, kinetics, sustainability, and cost-effectiveness. Herein, we investigated the efficiency of various phenothiazines and quinones in the electrochemical oxidation of FAD-GDH from Aspergillus terreus. At pH 7.0, the logarithm of the bimolecular oxidation rate constants appeared to depend on the redox potentials of all the mediators tested. Notably, the rate constant of each molecule for FAD-GDH was approximately 2.5 orders of magnitude higher than that for glucose oxidase from Aspergillus sp. The results suggest that the electron transfer kinetics is mainly determined by the formal potential of the mediator, the driving force of electron transfer, and the electron transfer distance between the redox active site of the mediator and the FAD, affected by the steric or chemical interactions. Higher k2 values were found for ortho-quinones than for para-quinones in the reactions with FAD-GDH and glucose oxidase, which was likely due to less steric hindrance in the active site in the case of the ortho-quinones.

  1. Orthodontic Force Application in Correlation with Salivary Lactate Dehydrogenase Activity

    Directory of Open Access Journals (Sweden)

    Erik Husin

    2013-07-01

    Full Text Available Orthodontic tooth movement generate mechanical forces to periodontal ligament and alveolar bone. The forces correlate with initial responses of periodontal tissues and involving many metabolic changes. One of the metabolic changes detected in saliva is lactate dehydrogenase (LDH activity. Objectives: To evaluate the correlation between orthodontic interrupted force application, lactate dehydrogenase activity and the distance of tooth movement. Methods: upper premolar, pre-retraction of upper canine and 1, 7, 14, 21 and 28 days post-retraction of upper canine with 100g interrupted orthodontic force. Results: duration of force (F=11.926 p 14 and 28 days post-retraction of canine. The region of retraction correlated with the distance of tooth movement (F=7.377 p=0.007. The duration of force correlated with the distance of tooth movement (F=66.554 p=0.000. retraction of canine. Conclusion: This study concluded that orthodontic interrupted force application on canine could increase the distance of tooth movement and LDH activity in saliva.

  2. High energy electron beam inactivation of lactate dehydrogenase suspended in different aqueous media

    International Nuclear Information System (INIS)

    Hategan, A.; Popescu, A.; Butan, C.; Oproiu, C.; Hategan, D.; Morariu, V.V.

    1999-01-01

    The direct and indirect effects of 5 MeV electron beam irradiation in the range (0-400 Gy) at 20 degC, 0 degC, -3 degC and -196 degC, as well as the influence of the aqueous suspending medium (ultrapure water and heavy water) on the total enzymatic activity of lactate dehydrogenase (LDH) have been studied. Our results showed an exponential decrease on the enzymatic activity of irradiated LDH, at all irradiation temperatures, independently of the direct or indirect action of radiation. The temperature gradient used to lower the temperature of the samples to -196 degC drastically influences the results. Freeze-thawing in two steps down to -196 degC protects LDH to radiation, in the dose range used. The data obtained here inform on the high energy electrons effects on the enzymatic activity loss during irradiation and during thawing, when the subsequent growth of the water crystals influences the three dimensional structure of the enzyme. A 99.98% concentration of D 2 O in the suspending medium of the enzyme decreases the global enzymatic activity, but reduces the rate of radiation inactivation of the enzyme. The rate of radiation inactivation of the enzyme suspended in ultrapure water is reduced when compared to the enzyme suspended in bidistilled water, but compared to the D 2 O suspended enzyme is lightly increased. (author)

  3. pH-dependent electron transfer reaction and direct bioelectrocatalysis of the quinohemoprotein pyranose dehydrogenase

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Kouta [Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan); Matsumura, Hirotoshi; Ishida, Takuya [Department of Biomaterial Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657 (Japan); Yoshida, Makoto [Department of Environmental and Natural Resource Science, Tokyo University of Agriculture and Technology, Fuchu, Tokyo 183-8509 (Japan); Igarashi, Kiyohiko; Samejima, Masahiro [Department of Biomaterial Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657 (Japan); Ohno, Hiroyuki [Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan); Nakamura, Nobuhumi, E-mail: nobu1@cc.tuat.ac.jp [Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Tokyo 184-8588 (Japan)

    2016-08-26

    A pyranose dehydrogenase from Coprinopsis cinerea (CcPDH) is an extracellular quinohemoeprotein, which consists a b-type cytochrome domain, a pyrroloquinoline-quinone (PQQ) domain, and a family 1-type carbohydrate-binding module. The electron transfer reaction of CcPDH was studied using some electron acceptors and a carbon electrode at various pH levels. Phenazine methosulfate (PMS) reacted directly at the PQQ domain, whereas cytochrome c (cyt c) reacted via the cytochrome domain of intact CcPDH. Thus, electrons are transferred from reduced PQQ in the catalytic domain of CcPDH to heme b in the N-terminal cytochrome domain, which acts as a built-in mediator and transfers electron to a heterogenous electron transfer protein. The optimal pH values of the PMS reduction (pH 6.5) and the cyt c reduction (pH 8.5) differ. The catalytic currents for the oxidation of L-fucose were observed within a range of pH 4.5 to 11. Bioelectrocatalysis of CcPDH based on direct electron transfer demonstrated that the pH profile of the biocatalytic current was similar to the reduction activity of cyt c characters. - Highlights: • pH dependencies of activity were different for the reduction of cyt c and DCPIP. • DET-based bioelectrocatalysis of CcPDH was observed. • The similar pH-dependent profile was found with cyt c and electrode. • The present results suggested that IET reaction of CcPDH shows pH dependence.

  4. Electron transfer between a quinohemoprotein alcohol dehydrogenase and an electrode via a redox polymer network

    NARCIS (Netherlands)

    Stigter, E.C.A.; Jong, G.A.H. de; Jongejan, J.A.; Duine, J.A.; Lugt, J.P. van der; Somers, W.A.C.

    1996-01-01

    A quinohemoprotein alcohol dehydrogenase (QH-EDH) from Comamonas testosteroni was immobilized on an electrode in a redox polymer network consisting of a polyvinylpyridine partially N-complexed with osmiumbis-(bipyridine)chloride. The enzyme effectively transfers electrons to the electrode via the

  5. A single arginine residue is required for the interaction of the electron transferring flavoprotein (ETF) with three of its dehydrogenase partners.

    Science.gov (United States)

    Parker, Antony R

    2003-12-01

    The interaction of several dehydrogenases with the electron transferring flavoprotein (ETF) is a crucial step required for the successful transfer of electrons into the electron transport chain. The exact determinants regarding the interaction of ETF with its dehydrogenase partners are still unknown. Chemical modification of ETF with arginine-specific reagents resulted in the loss, to varying degrees, of activity with medium chain acyl-coenzyme A dehydrogenase (MCAD). The kinetic profiles showed the inactivations followed pseudo-first-order kinetics for all reagents used. For activity with MCAD, maximum inactivation of ETF was accomplished by 2,3-butanedione (4% residual activity after 120 min) and it was shown that modification of one arginine residue was responsible for the inactivation. Almost 100% restoration of this ETF activity was achieved upon incubation with free arginine. However, the same 2,3-butanedione modified ETF only possessed decreased activity with dimethylglycine-(DMGDH, 44%) and sarcosine- (SDH, 27%) dehydrogenases unlike the abolition with MCAD. Full protection of ETF from arginine modification by 2,3-butanedione was achieved using substrate-protected DMGDH, MCAD and SDH respectively. Cross-protection studies of ETF with the three dehydrogenases implied use of the same single arginine residue in the binding of all three dehydrogenases. These results lead us to conclude that this single arginine residue is essential in the binding of the ETF to MCAD, but only contributes partially to the binding of ETF to SDH and DMGDH and thus, the determinants of the dehydrogenase binding sites overlap but are not identical.

  6. 9-Hydroxyprostaglandin dehydrogenase activity in the adult rat kidney. Regional distribution and sub-fractionation.

    Science.gov (United States)

    Asciak, C P; Domazet, Z

    1975-02-20

    1. Catabolism of prostaglandin F2alpha in the adult rat kidney takes place by the following sequence of enzymatic steps: (1) 15-hydroxyprostaglandin dehydrogenase; (2) prostaglandin delta13-reductase; and (3) 9-hydroxyprostaglandin dehydrogenase. 2. 9-Hydroxyprostaglandin dehydrogenase activity was highest in the cortex with lesser amounts in the medulla and negligible activity detected in the papilla. A similar distribution was observed for 15-hydroxyprostaglandin dehydrogenase and prostaglandin delta13-reductase. 3. Most of the 9-hydroxyprostaglandin dehydrogenase activity in the homogenate was found in the high-speed supernatant as also observed for 15-hydroxyprostaglandin dehydrogenase and prostaglandin delta13-reductase. 4. These observations indicate that the rat kidney contains an abundance of prostaglandin-catabolising enzymes which favour formation of metabolites of the E-type.

  7. Mediatorless electron transfer in glucose dehydrogenase/laccase system adsorbed on carbon nanotubes

    International Nuclear Information System (INIS)

    Ratautas, D.; Marcinkevičienė, L.; Meškys, R.; Kulys, J.

    2015-01-01

    Highlights: • Glucose dehydrogenase from Ewingella americana (GDH) demonstrated an effective mediatorless oxidation of glucose on single-walled carbon nanotubes (SWCNT). • Laccase from Trichaptum abietinum (LAC) exhibited mediatorless oxygen reduction when the enzyme was adsorbed on SWCNT. • Simultaneous adsorption of GDH and LAC on SWCNT formed an electron transfer chain in which glucose and lactose were oxidized by oxygen in mediatorless manner. - Abstract: A mediatorless electron transfer in the chain of glucose dehydrogenase (GDH) and laccase (LAC) catalysing the oxidation of glucose by molecular oxygen was studied. To demonstrate mediatorless processes, the GDH from Ewingella americana was adsorbed on single-walled carbon nanotubes (SWCNT). The effective mediatorless oxidation of glucose proceeded at 0.2–0.4 V vs. SCE. The electrode was most active at pH 6.1, and generated 0.8 mA cm −2 biocatalytic current in the presence of 50 mM glucose. The electrode showed a bell-shaped pH dependence with pK a values of 4.1 and 7.5. LAC from Trichaptum abietinum adsorbed on SWCNT exhibited mediatorless oxygen reduction at electrode potential less than 0.65 V. The electrode was most active at pH 3.0–4.0 and generated 1.1 mA cm −2 biocatalytic current in the presence of 0.254 mM oxygen, with an apparent pK a of 1.0 and 5.4. The electrodes prepared by simultaneous adsorption of GDH and LAC on SWCNT exhibited glucose oxidation at a potential higher than 0.25 V. The oxygen consumption in the chain was demonstrated using a Clark-type oxygen electrode. The dependence of oxygen consumption on glucose and lactose concentrations as well as activity of the system on pH were measured. A model of the pH dependence as well as mediatorless consecutive glucose oxidation with oxygen catalysed by LAC/GDH system is presented. This work provides a novel approach towards the synthesis of artificial multi enzyme systems by wiring oxidoreductases with SWCNT, and offers a better

  8. A Case of Hyperammonemia Associated with High Dihydropyrimidine Dehydrogenase Activity

    Directory of Open Access Journals (Sweden)

    Keiki Nagaharu

    2016-01-01

    Full Text Available Over the past decades, 5-Fluorouracil (5-FU has been widely used to treat several types of carcinoma, including esophageal squamous cell carcinoma. In addition to its common side effects, including diarrhea, mucositis, neutropenia, and anemia, 5-FU treatment has also been reported to cause hyperammonemia. However, the exact mechanism responsible for 5-FU-induced hyperammonemia remains unknown. We encountered an esophageal carcinoma patient who developed hyperammonemia when receiving 5-FU-containing chemotherapy but did not exhibit any of the other common adverse effects of 5-FU treatment. At the onset of hyperammonemia, laboratory tests revealed high dihydropyrimidine dehydrogenase (DPD activity and rapid 5-FU clearance. Our findings suggested that 5-FU hypermetabolism may be one of the key mechanisms responsible for hyperammonemia during 5-FU treatment.

  9. 17 beta-hydroxysteroid dehydrogenase activity in canine pancreas

    International Nuclear Information System (INIS)

    Mendoza-Hernandez, G.; Lopez-Solache, I.; Rendon, J.L.; Diaz-Sanchez, V.; Diaz-Zagoya, J.C.

    1988-01-01

    The mitochondrial fraction of the dog pancreas showed NAD(H)-dependent enzyme activity of 17 beta-hydroxysteroid dehydrogenase. The enzyme catalyzes oxidoreduction between androstenedione and testosterone. The apparent Km value of the enzyme for androstenedione was 9.5 +/- 0.9 microM, the apparent Vmax was determined as 0.4 nmol mg-1 min-1, and the optimal pH was 6.5. In phosphate buffer, pH 7.0, maximal rate of androstenedione reduction was observed at 37 degrees C. The oxidation of testosterone by the enzyme proceeded at the same rate as the reduction of the androstenedione at a pH of 6.8-7.0. The apparent Km value and the optimal pH of the enzyme for testosterone were 3.5 +/- 0.5 microM and 7.5, respectively

  10. Evaluation of Serum Lactate Dehydrogenase Activity in a Virtual Environment

    Directory of Open Access Journals (Sweden)

    V.M.T. Trindade

    2013-05-01

    Full Text Available Introduction: Lactate dehydrogenase is a citosolic enzyme involved in reversible transformation of pyruvate to lactate. It participates in anaerobic glycolysis of skeletal muscle and red blood cells, in liver gluconeogenesis and in aerobic metabolism of heart muscle. The determination of its activity helps in the diagnosis of various diseases, because it is increased in serum of patients suffering from myocardial infarction, acute hepatitis, muscular dystrophy and cancer. This paper presents a learning object, mediated by computer, which contains the simulation of the laboratory determination serum lactate dehydrogenase activity measured by the spectrophotometric method, based in the decrease of absorbance at 340 nm. Materials and Methods: Initially, pictures and videos were obtained recording the procedure of the methodology. The most representative images were selected, edited and inserted into an animation developed with the aid of the tool Adobe ® Flash ® CS3. The validation of the object was performed by the students of Biochemistry I (Pharmacy-UFRGS from the second semester of 2009 and both of 2010. Results and Discussion: The analysis of students' answers revealed that 80% attributed the excellence of the navigation program, the display format and to aid in learning. Conclusion: Therefore, this software can be considered an adequate teaching resource as well as an innovative support in the construction of theoretical and practical knowledge of Biochemistry. Available at: http://www6.ufrgs.br/gcoeb/LDH

  11. The multiplicity of dehydrogenases in the electron transport chain of plant mitochondria

    DEFF Research Database (Denmark)

    Rasmusson, Allan G; Geisler, Daniela A; Møller, Ian Max

    2008-01-01

    The electron transport chain in mitochondria of different organisms contains a mixture of common and specialised components. The specialised enzymes form branches to the universal electron path, especially at the level of ubiquinone, and allow the chain to adjust to different cellular and metabolic...... and their consequences for the understanding of electron transport and redundancy of electron paths...... requirements. In plants, specialised components have been known for a long time. However, recently, the known number of plant respiratory chain dehydrogenases has increased, including both components specific to plants and those with mammalian counterparts. This review will highlight the novel branches...

  12. Identification of the 2-hydroxyglutarate and isovaleryl-CoA dehydrogenases as alternative electron donors linking lysine catabolism to the electron transport chain of Arabidopsis mitochondria.

    Science.gov (United States)

    Araújo, Wagner L; Ishizaki, Kimitsune; Nunes-Nesi, Adriano; Larson, Tony R; Tohge, Takayuki; Krahnert, Ina; Witt, Sandra; Obata, Toshihiro; Schauer, Nicolas; Graham, Ian A; Leaver, Christopher J; Fernie, Alisdair R

    2010-05-01

    The process of dark-induced senescence in plants is relatively poorly understood, but a functional electron-transfer flavoprotein/electron-transfer flavoprotein:ubiquinone oxidoreductase (ETF/ETFQO) complex, which supports respiration during carbon starvation, has recently been identified. Here, we studied the responses of Arabidopsis thaliana mutants deficient in the expression of isovaleryl-CoA dehydrogenase and 2-hydroxyglutarate dehydrogenase to extended darkness and other environmental stresses. Evaluations of the mutant phenotypes following carbon starvation induced by extended darkness identify similarities to those exhibited by mutants of the ETF/ETFQO complex. Metabolic profiling and isotope tracer experimentation revealed that isovaleryl-CoA dehydrogenase is involved in degradation of the branched-chain amino acids, phytol, and Lys, while 2-hydroxyglutarate dehydrogenase is involved exclusively in Lys degradation. These results suggest that isovaleryl-CoA dehydrogenase is the more critical for alternative respiration and that a series of enzymes, including 2-hydroxyglutarate dehydrogenase, plays a role in Lys degradation. Both physiological and metabolic phenotypes of the isovaleryl-CoA dehydrogenase and 2-hydroxyglutarate dehydrogenase mutants were not as severe as those observed for mutants of the ETF/ETFQO complex, indicating some functional redundancy of the enzymes within the process. Our results aid in the elucidation of the pathway of plant Lys catabolism and demonstrate that both isovaleryl-CoA dehydrogenase and 2-hydroxyglutarate dehydrogenase act as electron donors to the ubiquinol pool via an ETF/ETFQO-mediated route.

  13. Interdomain electron transfer in cellobiose dehydrogenase is governed by surface electrostatics

    Czech Academy of Sciences Publication Activity Database

    Kádek, Alan; Kavan, Daniel; Marcoux, J.; Stojko, J.; Felice, A.K.G.; Cianférani, S.; Ludwig, R.; Halada, Petr; Man, Petr

    2017-01-01

    Roč. 1861, č. 2 (2017), s. 157-167 ISSN 0304-4165 R&D Projects: GA ČR GAP206/12/0503; GA MŠk(CZ) ED1.1.00/02.0109; GA MŠk(CZ) LQ1604 Institutional support: RVO:61388971 Keywords : Cellobiose dehydrogenase * Direct electron transfer * Electrostatic interaction Subject RIV: CE - Biochemistry OBOR OECD: Biochemistry and molecular biology Impact factor: 4.702, year: 2016

  14. Glutathionylation regulates cytosolic NADP+-dependent isocitrate dehydrogenase activity.

    Science.gov (United States)

    Shin, Seoung Woo; Oh, Chang Joo; Kil, In Sup; Park, Jeen-Woo

    2009-04-01

    Cytosolic NADP+-dependent isocitrate dehydrogenase (IDPc) is susceptible to inactivation by numerous thiol-modifying reagents. This study now reports that Cys269 of IDPc is a target for S-glutathionylation and that this modification is reversed by dithiothreitol as well as enzymatically by cytosolic glutaredoxin in the presence of GSH. Glutathionylated IDPc was significantly less susceptible than native protein to peptide fragmentation by reactive oxygen species and proteolytic digestion. Glutathionylation may play a protective role in the degradation of protein through the structural alterations of IDPc. HEK293 cells treated with diamide displayed decreased IDPc activity and accumulated glutathionylated enzyme. Using immunoprecipitation with an anti-IDPc IgG and immunoblotting with an anti-GSH IgG, we purified and positively identified glutathionylated IDPc from the kidneys of mice subjected to ischemia/reperfusion injury and from the livers of ethanol-administered rats. These results suggest that IDPc activity is modulated through enzymatic glutathionylation and deglutathionylation during oxidative stress.

  15. Designing a highly active soluble PQQ-glucose dehydrogenase for efficient glucose biosensors and biofuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Durand, Fabien [Universite de Bordeaux, Centre de Recherche Paul Pascal (CRPP), UPR 8641, Avenue Albert Schweitzer, 33600 Pessac (France); Stines-Chaumeil, Claire [Universite de Bordeaux, CNRS, Institut de Biochimie et de Genetique Cellulaires, 1 rue Camille Saint Saens, 33077 Bordeaux Cedex (France); Flexer, Victoria [Universite de Bordeaux, Centre de Recherche Paul Pascal (CRPP), UPR 8641, Avenue Albert Schweitzer, 33600 Pessac (France); Andre, Isabelle [Universite de Toulouse, INSA, UPS, INP, LISBP, 135 Avenue de Rangueil, F-31077 Toulouse (France); CNRS, UMR5504, F-31400 Toulouse (France); INRA, UMR 792 Ingenierie des Systemes Biologiques et des Procedes, F-31400 Toulouse (France); Mano, Nicolas, E-mail: mano@crpp-bordeaux.cnrs.fr [Universite de Bordeaux, Centre de Recherche Paul Pascal (CRPP), UPR 8641, Avenue Albert Schweitzer, 33600 Pessac (France)

    2010-11-26

    Research highlights: {yields} A new mutant of PQQ-GDH designed for glucose biosensors application. {yields} First mutant of PQQ-GDH with higher activity for D-glucose than the Wild type. {yields} Position N428 is a key point to increase the enzyme activity. {yields} Molecular modeling shows that the N428 C mutant displays a better interaction for PQQ than the WT. -- Abstract: We report for the first time a soluble PQQ-glucose dehydrogenase that is twice more active than the wild type for glucose oxidation and was obtained by combining site directed mutagenesis, modelling and steady-state kinetics. The observed enhancement is attributed to a better interaction between the cofactor and the enzyme leading to a better electron transfer. Electrochemical experiments also demonstrate the superiority of the new mutant for glucose oxidation and make it a promising enzyme for the development of high-performance glucose biosensors and biofuel cells.

  16. The Diagnostic Significance of Serum Alcohol Dehydrogenase Isoenzymes and Aldehyde Dehydrogenase Activity in Urinary Bladder Cancer Patients.

    Science.gov (United States)

    Orywal, Karolina; Jelski, Wojciech; Werel, Tadeusz; Szmitkowski, Maciej

    2017-07-01

    The aim of this study was to investigate a potential role of alcohol dehydrogenase and aldehyde dehydrogenase as tumor markers for urinary bladder cancer. Serum samples were obtained from 41 patients with bladder cancer and 52 healthy individuals. Class III and IV of ADH and total ADH activity were measured by the photometric method. For measurement of class I and II ADH and ALDH activity, the fluorometric method was employed. Significantly higher total activity of ADH was found in sera of both, low-grade and high-grade bladder cancer patients. The diagnostic sensitivity for total ADH activity was 81.5%, specificity 98.1%, positive (PPV) and negative (NPV) predictive values were 97.4% and 92.3% respectively. Area under ROC curve for total ADH activity was 0.848. A potential role of total ADH activity as a marker for bladder cancer, is herein proposed. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  17. Lactate dehydrogenase activity is inhibited by methylmalonate in vitro.

    Science.gov (United States)

    Saad, Laura O; Mirandola, Sandra R; Maciel, Evelise N; Castilho, Roger F

    2006-04-01

    Methylmalonic acidemia (MMAemia) is an inherited metabolic disorder of branched amino acid and odd-chain fatty acid metabolism, involving a defect in the conversion of methylmalonyl-coenzyme A to succinyl-coenzyme A. Systemic and neurological manifestations in this disease are thought to be associated with the accumulation of methylmalonate (MMA) in tissues and biological fluids with consequent impairment of energy metabolism and oxidative stress. In the present work we studied the effect of MMA and two other inhibitors of mitochondrial respiratory chain complex II (malonate and 3-nitropropionate) on the activity of lactate dehydrogenase (LDH) in tissue homogenates from adult rats. MMA potently inhibited LDH-catalyzed conversion of lactate to pyruvate in liver and brain homogenates as well as in a purified bovine heart LDH preparation. LDH was about one order of magnitude less sensitive to inhibition by MMA when catalyzing the conversion of pyruvate to lactate. Kinetic studies on the inhibition of brain LDH indicated that MMA inhibits this enzyme competitively with lactate as a substrate (K (i)=3.02+/-0.59 mM). Malonate and 3-nitropropionate also strongly inhibited LDH-catalyzed conversion of lactate to pyruvate in brain homogenates, while no inhibition was observed by succinate or propionate, when present in concentrations of up to 25 mM. We propose that inhibition of the lactate/pyruvate conversion by MMA contributes to lactate accumulation in blood, metabolic acidemia and inhibition of gluconeogenesis observed in patients with MMAemia. Moreover, the inhibition of LDH in the central nervous system may also impair the lactate shuttle between astrocytes and neurons, compromising neuronal energy metabolism.

  18. Inhibition of dehydrogenase activity in petroleum refinery wastewater bacteria by phenolic compounds

    OpenAIRE

    Gideon C. Okpokwasili; Christian Okechukwu Nweke

    2010-01-01

    The toxicity of phenol, 2-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, 2-chlorophenol, 4-chlorophenol, 4-bromophenol and 3,5-dimethylphenol on Pseudomonas, Bacillus and Escherichia species isolated from petroleum refinery wastewater was assessed via inhibition of dehydrogenase enzyme activity. At low concentrations, 2-nitrophenol, 2-chlorophenol, 4-chlorophenol, 4-bromophenol and 3,5-dimethylphenol stimulated dehydrogenase activity and at sufficient concentrations, phenolic compounds inhibi...

  19. Assessment of creatine kinase and lactate dehydrogenase activities ...

    African Journals Online (AJOL)

    Ina bid to investigate the influence of menopausal on coronary heart disease, plasma creatine kinase (CK) and lactate dehydrogenase (LDH) enzymes were analysed on a prospective cohort of 100 women attending Irrua Specialist Teaching Hospital (ISTH), Irrua, Edo state-Nigeria. They were divided into two groups; ...

  20. Cytophotometry of glucose-6-phosphate dehydrogenase activity in individual cells

    NARCIS (Netherlands)

    van Noorden, C. J.; Tas, J.; Vogels, I. M.

    1983-01-01

    With the aid of thin films of polyacrylamide gel containing purified glucose-6-phosphate dehydrogenase subjected to cytochemical procedures for the enzyme using tetranitro blue tetrazolium, arbitrary units of integrated absorbance obtained with a Barr & Stroud GN5 cytophotometer were converted into

  1. Inosine monophosphate dehydrogenase messenger RNA expression is correlated to clinical outcomes in mycophenolate mofetil-treated kidney transplant patients, whereas inosine monophosphate dehydrogenase activity is not

    NARCIS (Netherlands)

    Sombogaard, Ferdi; Peeters, Annemiek M. A.; Baan, Carla C.; Mathot, Ron A. A.; Quaedackers, Monique E.; Vulto, Arnold G.; Weimar, Willem; van Gelder, Teun

    2009-01-01

    Measurement of the pharmacodynamic biomarker inosine monophosphate dehydrogenase (IMPDH) activity in renal transplant recipients has been proposed to reflect the biological effect better than using pharmacokinetic parameters to monitor mycophenolate mofetil therapy. The IMPDH assays are however

  2. Interdomain electron transfer in cellobiose dehydrogenase is governed by surface electrostatics.

    Science.gov (United States)

    Kadek, Alan; Kavan, Daniel; Marcoux, Julien; Stojko, Johann; Felice, Alfons K G; Cianférani, Sarah; Ludwig, Roland; Halada, Petr; Man, Petr

    2017-02-01

    Cellobiose dehydrogenase (CDH) is a fungal extracellular oxidoreductase which fuels lytic polysaccharide monooxygenase with electrons during cellulose degradation. Interdomain electron transfer between the flavin and cytochrome domain in CDH, preceding the electron flow to lytic polysaccharide monooxygenase, is known to be pH dependent, but the exact mechanism of this regulation has not been experimentally proven so far. To investigate the structural aspects underlying the domain interaction in CDH, hydrogen/deuterium exchange (HDX-MS) with improved proteolytic setup (combination of nepenthesin-1 with rhizopuspepsin), native mass spectrometry with ion mobility and electrostatics calculations were used. HDX-MS revealed pH-dependent changes in solvent accessibility and hydrogen bonding at the interdomain interface. Electrostatics calculations identified these differences to result from charge neutralization by protonation and together with ion mobility pointed at higher electrostatic repulsion between CDH domains at neutral pH. In addition, we uncovered extensive O-glycosylation in the linker region and identified the long-unknown exact cleavage point in papain-mediated domain separation. Transition of CDH between its inactive (open) and interdomain electron transfer-capable (closed) state is shown to be governed by changes in the protein surface electrostatics at the domain interface. Our study confirms that the interdomain electrostatic repulsion is the key factor modulating the functioning of CDH. The results presented in this paper provide experimental evidence for the role of charge repulsion in the interdomain electron transfer in cellobiose dehydrogenases, which is relevant for exploiting their biotechnological potential in biosensors and biofuel cells. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Soil dehydrogenase activity of natural macro aggregates in a toposequence of forest soil

    Directory of Open Access Journals (Sweden)

    Maira Kussainova

    2013-01-01

    Full Text Available The main objective of this study was to determine changes in soil dehydrogenase activity in natural macro aggregates development along a slope in forest soils. This study was carried out in Kocadag, Samsun, Turkey. Four landscape positions i.e., summit, shoulder backslope and footslope, were selected. For each landseape position, soil macro aggregates were separated into six aggregate size classes using a dry sieving method and then dehydrogenase activity was analyzed. In this research, topography influenced the macroaggregate size and dehydrogenase activity within the aggregates. At all landscape positions, the contents of macro aggregates (especially > 6.3 mm and 2.00–4.75 mm in all soil samples were higher than other macro aggregate contents. In footslope position, the soils had generally the higher dehydrogenase activity than the other positions at all landscape positions. In all positions, except for shoulder, dehydrogenase activity was greater macro aggregates of <1 mm than in the other macro aggregate size.

  4. Glucose-6-phosphate dehydrogenase activity decreases during storage of leukoreduced red blood cells

    NARCIS (Netherlands)

    Peters, Anna L.; van Bruggen, Robin; de Korte, Dirk; van Noorden, Cornelis J. F.; Vlaar, Alexander P. J.

    2016-01-01

    During storage, the activity of the red blood cell (RBC) antioxidant system decreases. Glucose-6-phosphate dehydrogenase (G6PD) is essential for protection against oxidative stress by producing NADPH. G6PD function of RBC transfusion products is reported to remain stable during storage, but activity

  5. Growth hormone-induced insulin resistance in human subjects involves reduced pyruvate dehydrogenase activity

    DEFF Research Database (Denmark)

    Nellemann, B.; Vendelbo, M.H.; Nielsen, Thomas Svava

    2014-01-01

    Insulin resistance induced by growth hormone (GH) is linked to promotion of lipolysis by unknown mechanisms. We hypothesized that suppression of the activity of pyruvate dehydrogenase in the active form (PDHa) underlies GH-induced insulin resistance similar to what is observed during fasting....

  6. Potentiation of insulin release in response to amino acid methyl esters correlates to activation of islet glutamate dehydrogenase activity

    DEFF Research Database (Denmark)

    Kofod, Hans; Lernmark, A; Hedeskov, C J

    1986-01-01

    Column perifusion of mouse pancreatic islets was used to study the ability of amino acids and their methyl esters to influence insulin release and activate islet glutamate dehydrogenase activity. In the absence of L-glutamine, L-serine and the methyl ester of L-phenylalanine, but neither L...... glutamate dehydrogenase activity showed that only the two methyl esters of L-phenylalanine and L-serine activated the enzyme. It is concluded that the mechanism by which methyl esters of amino acids potentiate insulin release is most likely to be mediated by the activation of pancreatic beta-cell glutamate...

  7. Electronically type-sorted carbon nanotube-based electrochemical biosensors with glucose oxidase and dehydrogenase.

    Science.gov (United States)

    Muguruma, Hitoshi; Hoshino, Tatsuya; Nowaki, Kohei

    2015-01-14

    An electrochemical enzyme biosensor with electronically type-sorted (metallic and semiconducting) single-walled carbon nanotubes (SWNTs) for use in aqueous media is presented. This research investigates how the electronic types of SWNTs influence the amperometric response of enzyme biosensors. To conduct a clear evaluation, a simple layer-by-layer process based on a plasma-polymerized nano thin film (PPF) was adopted because a PPF is an inactive matrix that can form a well-defined nanostructure composed of SWNTs and enzyme. For a biosensor with the glucose oxidase (GOx) enzyme in the presence of oxygen, the response of a metallic SWNT-GOx electrode was 2 times larger than that of a semiconducting SWNT-GOx electrode. In contrast, in the absence of oxygen, the response of the semiconducting SWNT-GOx electrode was retained, whereas that of the metallic SWNT-GOx electrode was significantly reduced. This indicates that direct electron transfer occurred with the semiconducting SWNT-GOx electrode, whereas the metallic SWNT-GOx electrode was dominated by a hydrogen peroxide pathway caused by an enzymatic reaction. For a biosensor with the glucose dehydrogenase (GDH; oxygen-independent catalysis) enzyme, the response of the semiconducting SWNT-GDH electrode was 4 times larger than that of the metallic SWNT-GDH electrode. Electrochemical impedance spectroscopy was used to show that the semiconducting SWNT network has less resistance for electron transfer than the metallic SWNT network. Therefore, it was concluded that semiconducting SWNTs are more suitable than metallic SWNTs for electrochemical enzyme biosensors in terms of direct electron transfer as a detection mechanism. This study makes a valuable contribution toward the development of electrochemical biosensors that employ sorted SWNTs and various enzymes.

  8. Evolution of D-lactate dehydrogenase activity from glycerol dehydrogenase and its utility for D-lactate production from lignocellulose

    Science.gov (United States)

    Wang, Qingzhao; Ingram, Lonnie O.; Shanmugam, K. T.

    2011-01-01

    Lactic acid, an attractive, renewable chemical for production of biobased plastics (polylactic acid, PLA), is currently commercially produced from food-based sources of sugar. Pure optical isomers of lactate needed for PLA are typically produced by microbial fermentation of sugars at temperatures below 40 °C. Bacillus coagulans produces L(+)-lactate as a primary fermentation product and grows optimally at 50 °C and pH 5, conditions that are optimal for activity of commercial fungal cellulases. This strain was engineered to produce D(−)-lactate by deleting the native ldh (L-lactate dehydrogenase) and alsS (acetolactate synthase) genes to impede anaerobic growth, followed by growth-based selection to isolate suppressor mutants that restored growth. One of these, strain QZ19, produced about 90 g L-1 of optically pure D(−)-lactic acid from glucose in coagulans and the QZ19 derivative can be used to produce either L(+) or D(−) optical isomers of lactic acid (respectively) at high titers and yields from nonfood carbohydrates. PMID:22065761

  9. Inhibition of dehydrogenase activity in petroleum refinery wastewater bacteria by phenolic compounds

    Directory of Open Access Journals (Sweden)

    Gideon C. Okpokwasili

    2010-04-01

    Full Text Available The toxicity of phenol, 2-nitrophenol, 4-nitrophenol, 2,4-dinitrophenol, 2-chlorophenol, 4-chlorophenol, 4-bromophenol and 3,5-dimethylphenol on Pseudomonas, Bacillus and Escherichia species isolated from petroleum refinery wastewater was assessed via inhibition of dehydrogenase enzyme activity. At low concentrations, 2-nitrophenol, 2-chlorophenol, 4-chlorophenol, 4-bromophenol and 3,5-dimethylphenol stimulated dehydrogenase activity and at sufficient concentrations, phenolic compounds inhibited dehydrogenase activities. Generally, phenol is less toxic than substituted phenols. Estimations of the degree of inhibition/stimulation of dehydrogenase activities showed significant dose-dependent responses that are describable by logistic functions. The toxicity thresholds varied significantly (P < 0.05 among the bacterial strains and phenolic compounds. The median inhibitory concentrations (IC50s ranged from 4.118 ± 0.097 mg.L-1 for 4-nitrophenol against Pseudomonas sp. DAF1 to 1407.997 ± 7.091 mg.L-1 for phenol against Bacillus sp. DISK1. This study suggested that the organisms have moderate sensitivity to phenols and have the potential to be used as indicators for assessment of chemical toxicity. They could also be used as catalysts for degradation of phenols in effluents.

  10. Posttranslational regulation of glucose-6-phosphate dehydrogenase activity in tongue epithelium

    NARCIS (Netherlands)

    Biagiotti, E.; Bosch, K. S.; Ninfali, P.; Frederiks, W. M.; van Noorden, C. J.

    2000-01-01

    Expression of glucose-6-phosphate dehydrogenase (G6PD) activity is high in tongue epithelium, but its exact function is still unknown, it may be related;either to the high proliferation rate of this tissue or to protection against oxidative stress. To elucidate its exact role, we localized

  11. The Effects of Fenarimol and Methyl Parathion on Glucose 6-Phosphate Dehydrogenase Enzyme Activity in Rats

    Directory of Open Access Journals (Sweden)

    Ferda ARI

    2017-10-01

    Full Text Available Fenarimol and methyl parathion are pesticides that have been used in agriculture for several years. These pesticides have significant effects on environmental and human health. Therefore, we investigated the effects of methyl parathion and fenarimol on glucose 6-phosphate dehydrogenase (EC 1.1.1.49 enzyme activity in rats. The glucose 6- phosphate dehydrogenase is the first enzyme of the pentose phosphate pathway and it is important in detoxifying reactions by NADPH generated. In this study, wistar albino rats administrated with methyl parathion (7 mg kg–1 and fenarimol (200 mg kg−1 by intraperitoneally for different periods (2, 4, 8, 16, 32, 64, and 72 h. The glucose 6-phosphate dehydrogenase enzyme activity was assayed in liver, kidney, brain, and small intestine in male and female rats. The exposure of fenarimol and methyl parathion caused increase of glucose 6-phosphate dehydrogenase enzyme activity in rat tissues, especially at last periods. We suggest that this increment of enzyme activity may be the reason of toxic effects of fenarimol and methyl parathion.

  12. 3-cyanoindole-based inhibitors of inosine monophosphate dehydrogenase: synthesis and initial structure-activity relationships.

    Science.gov (United States)

    Dhar, T G Murali; Shen, Zhongqi; Gu, Henry H; Chen, Ping; Norris, Derek; Watterson, Scott H; Ballentine, Shelley K; Fleener, Catherine A; Rouleau, Katherine A; Barrish, Joel C; Townsend, Robert; Hollenbaugh, Diane L; Iwanowicz, Edwin J

    2003-10-20

    A series of novel small molecule inhibitors of inosine monophosphate dehydrogenase (IMPDH), based upon a 3-cyanoindole core, were explored. IMPDH catalyzes the rate determining step in guanine nucleotide biosynthesis and is a target for anticancer, immunosuppressive and antiviral therapy. The synthesis and the structure-activity relationships (SAR), derived from in vitro studies, for this new series of inhibitors is given.

  13. Exercise-induced pyruvate dehydrogenase activation is not affected by 7 days of bed rest

    DEFF Research Database (Denmark)

    Kiilerich, Kristian; Jørgensen, Stine Ringholm; Biensø, Rasmus Sjørup

    2011-01-01

    To test the hypothesis that physical inactivity impairs the exercise-induced modulation of pyruvate dehydrogenase (PDH), 6 healthy normally physically active male subjects completed 7 days of bed rest. Before and immediately after the bed rest, the subjects completed an OGTT and a one-legged knee...

  14. Fecal hydroxysteroid dehydrogenase activities in vegetarian Seventh-Day Adventists, control subjects, and bowel cancer patients.

    Science.gov (United States)

    Macdonald, I A; Webb, G R; Mahony, D E

    1978-10-01

    Cell-free extracts were prepared from mixed fecal anaerobic bacteria grown from stools of 14 vegetarian Seventh-Day Adventists, 16 omnivorous control subjects, and eight patients recently diagnosed with cancer of the large bowel. Preparations were assayed for NAD- and NADP-dependent 3alpha-, 7alpha- and 12alpha-hydroxysteroid dehydrogenases with bile salts and androsterone as substrates (eight substrate-cofactor combinations were tested). A significant intergroup difference was observed in the amounts of NAD- and NADP-dependent 7alpha-hydroxysteroid dehydrogenase produced: bowel cancer patients exceeded controls, and controls exceeded Seventh-Day Adventists. Other enzyme activity comparisons were not significant. The pH values of the stools were significantly higher in cancer patients compared to Seventh-Day Adventists; values were 7.03 +/- 0.60 and 6.46 +/- 0.58 respectively. The pH value for controls was 6.66 +/- 0.62. A plot of pH value versus NADP-dependent 7alpha-hydroxysteroid dehydrogenase tended to separate the cancer patients from the other groups. Comparative data suggest that much of the 3alpha-hydroxysteroid dehydrogenase active against bile salt is also active against androsterone.

  15. Effects of sh-reagents on rat hepatic aldehyde dehydrogenase activity

    Energy Technology Data Exchange (ETDEWEB)

    Konoplitskaya, K.L.; Kuz' mina, G.I.; Grigor' yeva, M.V.; Poznyakova, T.N.

    The liver serves as the primary organ for the oxidation of ingested ethanol via a pathway involving alcohol- and aldehyde dehydrogenase. In view of the problem of alcoholism, three enzymes are of particular interest in understanding the biochemical mechanism that may be involved in alcohol addiction and in the formulation of therapeutic approaches. While alcohol dehydrogenase has been studied in considerable detail, current attention is centered on aldehyde dehydrogenase. A comparative analysis of the effects of a series of SH-active reagents - tetraethylthiuram disulfide (TETD), 5,5-dithiobisnitrobenzoic acid (DTNB), p-chloromercurybenzoate (PCMB), and N-ethylmaleimide (NEM) - were tested for their effects on the activity of aldehyde dehydrogenase of the hepatic mitochondrial (isozymes I and II) and microsomal (isozyme II) fractions of outbred albino rats. DTNB was found to be inhibited by 100 and 50% mitochondrial isozymes I and II, respectively, and by 20%, the microsomal enzyme under the conditions employed. DTNB and NEM inhibited by 30 and 50% isozymes I and II of the mitochondria, but had no effect on the microsomal isozyme. 24 references, 3 figures.

  16. Succinate Dehydrogenase Activity Assay in situ with Blue Tetrazolium Salt in Crabtree-Positive Saccharomyces cerevisiae Strain

    Directory of Open Access Journals (Sweden)

    Joanna Berlowska

    2008-01-01

    Full Text Available A spectrophotometric method for determining succinate dehydrogenase (SDH activity assay in azide-sensitive yeast Saccharomyces cerevisiae has been developed. The permeabilization of yeast cells by 0.05 % digitonin permitted to study yeast enzymatic activity in situ. The reduction of blue tetrazolium salt (BT to blue tetrazolium formazan (BTf was conducted in the presence of phenazine methosulphate (PMS as an exogenous electron carrier, and sodium azide (SA as an inhibitor of cytochrome oxidase (Cyt pathway. Various factors such as type of substrate, BT concentration, cell number, temperature and time of incubation, and different Cyt pathway blockers were optimized. In earlier studies, dimethyl sulfoxide (DMSO had been selected as the best solvent for extraction of BTf from yeast cells. The linear correlation between permeabilized yeast cell density and amount of formed formazan was evidenced in the range from 9·10^7 to 5·10^8 cells per sample solution. Below the yeast cell concentration of 10^7 the absorbance values were too low to detect formazans with good precision. This standarized procedure allows the estimation of SDH activity in whole cells, depending on vitality level of yeast populations. Significant increases of succinate dehydrogenase activities were observed in sequential passages as the result of the increase of activity of the strain and adaptation to cultivation conditions.

  17. Electron-transfer mediator for a NAD-glucose dehydrogenase-based glucose sensor.

    Science.gov (United States)

    Kim, Dong-Min; Kim, Min-yeong; Reddy, Sanapalli S; Cho, Jaegeol; Cho, Chul-ho; Jung, Suntae; Shim, Yoon-Bo

    2013-12-03

    A new electron-transfer mediator, 5-[2,5-di (thiophen-2-yl)-1H-pyrrol-1-yl]-1,10-phenanthroline iron(III) chloride (FePhenTPy) oriented to the nicotinamide adenine dinucleotide-dependent-glucose dehydrogenase (NAD-GDH) system was synthesized through a Paal-Knorr condensation reaction. The structure of the mediator was confirmed by Fourier-transform infrared spectroscopy, proton and carbon nucler magnetic resonance spectroscopy, and mass spectroscopy, and its electron-transfer characteristic for a glucose sensor was investigated using voltammetry and impedance spectroscopy. A disposable amperometric glucose sensor with NAD-GDH was constructed with FePhenTPy as an electron-transfer mediator on a screen printed carbon electrode (SPCE) and its performance was evaluated, where the addition of reduces graphene oxide (RGO) to the mediator showed the enhanced sensor performance. The experimental parameters to affect the analytical performance and the stability of the proposed glucose sensor were optimized, and the sensor exhibited a dynamic range between 30 mg/dL and 600 mg/dL with the detection limit of 12.02 ± 0.6 mg/dL. In the real sample experiments, the interference effects by acetaminophen, ascorbic acid, dopamine, uric acid, caffeine, and other monosaccharides (fructose, lactose, mannose, and xylose) were completely avoided through coating the sensor surface with the Nafion film containing lead(IV) acetate. The reliability of proposed glucose sensor was evaluated by the determination of glucose in artificial blood and human whole blood samples.

  18. 15-hydroxyprostaglandin dehydrogenase activity in vitro in lung and kidney of essential fatty acid-deficient rats

    DEFF Research Database (Denmark)

    Hansen, Harald S.; Toft, B.S.

    1978-01-01

    Weanling rats were fed for 6 months on a diet deficient in essential fatty acids: either fat-free, or with 28% (w/w) partially hydrogenated fish oil. Control rats were fed a diet with 28% (w/w) arachis oil for 6 months. 15-Hydroxyprostaglandin dehydrogenase activity was determined as initial rates...... of the two groups on diets deficient in essential fatty acids as compared to the control group. No difference was observed in dehydrogenase activity in the kidneys. The dehydrogenase may be of importance for the regulation of the level of endogenous prostaglandins and, thus, a decrease in activity could...

  19. Serum creatine kinase and lactate dehydrogenase activities in ...

    African Journals Online (AJOL)

    Background and Objectives: There is the recognition of a pattern of elevations of serum enzymes in hyperthyroid and hypothyroid patients. The aims of this study were to determine the activities of serum creatine kinase (CK) and lactate deydrogenase (LDH) in thyroid disorders, and to evaluate the relationship between CK, ...

  20. Cellobiose Dehydrogenase Aryl Diazonium Modified Single Walled Carbon Nanotubes: Enhanced Direct Electron Transfer through a Positively Charged Surface

    Science.gov (United States)

    2011-01-01

    One of the challenges in the field of biosensors and biofuel cells is to establish a highly efficient electron transfer rate between the active site of redox enzymes and electrodes to fully access the catalytic potential of the biocatalyst and achieve high current densities. We report on very efficient direct electron transfer (DET) between cellobiose dehydrogenase (CDH) from Phanerochaete sordida (PsCDH) and surface modified single walled carbon nanotubes (SWCNT). Sonicated SWCNTs were adsorbed on the top of glassy carbon electrodes and modified with aryl diazonium salts generated in situ from p-aminobenzoic acid and p-phenylenediamine, thus featuring at acidic pH (3.5 and 4.5) negative or positive surface charges. After adsorption of PsCDH, both electrode types showed excellent long-term stability and very efficient DET. The modified electrode presenting p-aminophenyl groups produced a DET current density of 500 μA cm−2 at 200 mV vs normal hydrogen reference electrode (NHE) in a 5 mM lactose solution buffered at pH 3.5. This is the highest reported DET value so far using a CDH modified electrode and comes close to electrodes using mediated electron transfer. Moreover, the onset of the electrocatalytic current for lactose oxidation started at 70 mV vs NHE, a potential which is 50 mV lower compared to when unmodified SWCNTs were used. This effect potentially reduces the interference by oxidizable matrix components in biosensors and increases the open circuit potential in biofuel cells. The stability of the electrode was greatly increased compared with unmodified but cross-linked SWCNTs electrodes and lost only 15% of the initial current after 50 h of constant potential scanning. PMID:21417322

  1. Determination of dehydrogenase activities involved in D-glucose oxidation in Gluconobacter and Acetobacter strains

    Directory of Open Access Journals (Sweden)

    Florencia Sainz

    2016-08-01

    Full Text Available Acetic acid bacteria (AAB are known for rapid and incomplete oxidation of an extensively variety of alcohols and carbohydrates, resulting in the accumulation of organic acids as the final products. These oxidative fermentations in AAB are catalyzed by PQQ- or FAD- dependent membrane bound dehydrogenases. In the present study, the enzyme activity of the membrane bound dehydrogenases (membrane-bound PQQ-glucose dehydrogenase (mGDH, D-gluconate dehydrogenase (GADH and membrane-bound glycerol dehydrogenase (GLDH involved in the oxidation of D-glucose and D-gluconic acid (GA was determined in six strains of three different species of AAB (three natural and three type strains. Moreover, the effect of these activities on the production of related metabolites (GA, 2-keto-D-gluconic acid (2KGA and 5-keto-D-gluconic acid (5KGA was analyzed. The natural strains belonging to Gluconobacter showed a high mGDH activity and low activity in GADH and GLDH, whereas the A. malorum strain presented low activity in the three enzymes. Nevertheless, no correlation was observed between the activity of these enzymes and the concentration of the corresponding metabolites. In fact, all the tested strains were able to oxidize D-glucose to GA, being maximal at the late exponential phase of the AAB growth (24 h, which coincided with glucose exhaustion and the maximum mGDH activity. Instead, only some of the tested strains were capable of producing 2KGA and/or 5KGA. In the case of G. oxydans strains, no 2KGA production was detected which is related to the absence of GADH activity after 24 h, while in the remaining strains, detection of GADH activity after 24h resulted in a high accumulation of 2KGA. Therefore, it is possible to choose the best strain depending on the desired product composition.Moreover, the sequences of these genes were used to construct phylogenetic trees. According to the sequence of gcd, gene coding for mGDH, Acetobacter and Komagataeibacter were

  2. Identification of the 2-Hydroxyglutarate and Isovaleryl-CoA Dehydrogenases as Alternative Electron Donors Linking Lysine Catabolism to the Electron Transport Chain of Arabidopsis Mitochondria[W][OA

    Science.gov (United States)

    Araújo, Wagner L.; Ishizaki, Kimitsune; Nunes-Nesi, Adriano; Larson, Tony R.; Tohge, Takayuki; Krahnert, Ina; Witt, Sandra; Obata, Toshihiro; Schauer, Nicolas; Graham, Ian A.; Leaver, Christopher J.; Fernie, Alisdair R.

    2010-01-01

    The process of dark-induced senescence in plants is relatively poorly understood, but a functional electron-transfer flavoprotein/electron-transfer flavoprotein:ubiquinone oxidoreductase (ETF/ETFQO) complex, which supports respiration during carbon starvation, has recently been identified. Here, we studied the responses of Arabidopsis thaliana mutants deficient in the expression of isovaleryl-CoA dehydrogenase and 2-hydroxyglutarate dehydrogenase to extended darkness and other environmental stresses. Evaluations of the mutant phenotypes following carbon starvation induced by extended darkness identify similarities to those exhibited by mutants of the ETF/ETFQO complex. Metabolic profiling and isotope tracer experimentation revealed that isovaleryl-CoA dehydrogenase is involved in degradation of the branched-chain amino acids, phytol, and Lys, while 2-hydroxyglutarate dehydrogenase is involved exclusively in Lys degradation. These results suggest that isovaleryl-CoA dehydrogenase is the more critical for alternative respiration and that a series of enzymes, including 2-hydroxyglutarate dehydrogenase, plays a role in Lys degradation. Both physiological and metabolic phenotypes of the isovaleryl-CoA dehydrogenase and 2-hydroxyglutarate dehydrogenase mutants were not as severe as those observed for mutants of the ETF/ETFQO complex, indicating some functional redundancy of the enzymes within the process. Our results aid in the elucidation of the pathway of plant Lys catabolism and demonstrate that both isovaleryl-CoA dehydrogenase and 2-hydroxyglutarate dehydrogenase act as electron donors to the ubiquinol pool via an ETF/ETFQO-mediated route. PMID:20501910

  3. The role of exogenous electron carriers in NAD(P)-dependent dehydrogenase cytochemistry studied in vitro and with a model system of polyacrylamide films

    NARCIS (Netherlands)

    van Noorden, C. J.; Tas, J.

    1982-01-01

    The applicability of phenazine methosulfate, 1-methoxyphenazine methosulfate, menadione, and meldola blue as exogenous electron carriers for the cytochemical staining of nicotinamide adenine dinucleotide (phosphate) (NAD(P))-dependent dehydrogenases has been studied quantitatively with tetranitro BT

  4. Changes in cinnamyl alcohol dehydrogenase activities from sugarcane cultivars inoculated with Sporisorium scitamineum sporidia.

    Science.gov (United States)

    Santiago, Rocío; Alarcón, Borja; de Armas, Roberto; Vicente, Carlos; Legaz, María Estrella

    2012-06-01

    This study describes a method for determining cinnamyl alcohol dehydrogenase activity in sugarcane stems using reverse phase (RP) high-performance liquid chromatography to elucidate their possible lignin origin. Activity is assayed using the reverse mode, the oxidation of hydroxycinnamyl alcohols into hydroxycinnamyl aldehydes. Appearance of the reaction products, coniferaldehyde and sinapaldehyde is determined by measuring absorbance at 340 and 345 nm, respectively. Disappearance of substrates, coniferyl alcohol and sinapyl alcohol is measured at 263 and 273 nm, respectively. Isocratic elution with acetonitrile:acetic acid through an RP Mediterranea sea C18 column is performed. As case examples, we have examined two different cultivars of sugarcane; My 5514 is resistant to smut, whereas B 42231 is susceptible to the pathogen. Inoculation of sugarcane stems elicits lignification and produces significant increases of coniferyl alcohol dehydrogenase (CAD) and sinapyl alcohol dehydrogenase (SAD). Production of lignin increases about 29% in the resistant cultivar and only 13% in the susceptible cultivar after inoculation compared to uninoculated plants. Our results show that the resistance of My 5514 to smut is likely derived, at least in part, to a marked increase of lignin concentration by the activation of CAD and SAD. Copyright © Physiologia Plantarum 2012.

  5. Influence of adrenaline on the activity of succinate dehydrogenase in peripheral blood lymphocytes of irradiated rats

    International Nuclear Information System (INIS)

    Koroleva, L.V.; Vasin, M.V.

    1988-01-01

    In experiments with albino mongrel female rats, the influence of adrenaline on succinate dehydrogenase (SDG) activity in the peripheral blood lymphocytes of irradiated and intact animals has been investigated. Two minutes after the intraperitoneal administration of adrenaline (1 mg/kg) to intact rats SDG activity sharply rises and 3-4 min it drastically falls. In 6 to 8 min the second peak in the enzyme activity is registered. Twenty minutes after irradiation of rats in the crano-caudal direction with a dose of 75 Gy delivered to head, the reaction to adrenaline, manifested by the rise in SDG activity, is absent

  6. The activity state of the branched-chain 2-oxo acid dehydrogenase complex in rat tissues.

    OpenAIRE

    Wagenmakers, A J; Schepens, J T; Veldhuizen, J A; Veerkamp, J H

    1984-01-01

    An assay is described to define the proportion of the branched-chain 2-oxo acid dehydrogenase complex that is present in the active state in rat tissues. Activities are measured in homogenates in two ways: actual activities, present in tissues, by blocking both the kinase and phosphatase of the enzyme complex during homogenization, preincubation, and incubation with 1-14C-labelled branched-chain 2-oxo acid, and total activities by blocking only the kinase during the 5 min preincubation (neces...

  7. Changes of α-glycerophosphate dehydrogenase activity in fatty liver of rats by amino acid imbalance

    International Nuclear Information System (INIS)

    Ogura, Masaji; Katsunuma, Eiichi; Akabane, Tomoko; Ogawa, Seiichi

    1976-01-01

    The previous study on the lipogenesis in the fatty livers of rats, which was induced by feeding the diet with imbalanced amino acid, revealed that the induction of this type of fatty livers was due mainly to the acceleration of triglyceride synthesis by the increase in both synthesis and esterification of fatty acid in the livers. Although many studies have been carried out on the dietary control of α-glycerophosphate dehydrogenase activity in rat livers, the enzyme change in amino acid imbalance has not been reported. In the present study, in order to elucidate the difference in the supply of glycerol moiety of triglyceride due to the imbalance, the change of the α-glycerophosphate dehydrogenase activity in livers was investigated. The experimental diets were 8% casein basal diet and basal + 0.3% DL-methionine imbalanced diet. 5 rats of each group were killed after 0.5 and 10 days on the diet, and the analysis of the lipid content in the livers and the determination of the α-glycerophosphate dehydrogenase activity were carried out. The linear response of the enzyme activity to time and protein concentration was obtained. The development of fatty livers was observed in the imbalanced diet group in the feeding period of 10 days. It was found that the specific activity of the imbalanced diet group increased significantly in 5 and 10 days as compared with that of the basal diet group. The elevation in the enzyme activity may suggest that the supply of α-glycerophosphate for triglyceride synthesis is also increased in this type of fatty livers. (Kako, I.)

  8. Differential effects of acute and chronic fructose administration on pyruvate dehydrogenase activity and lipogenesis

    International Nuclear Information System (INIS)

    Wilson, L.

    1988-01-01

    These studies were undertaken to distinguish between the acute and chronic effects of fructose administration. In vivo, liver lipogenesis, as measured by 3 H 2 O incorporation, was greater in rats fed 60% fructose than in their glucose fed controls. Both fructose feeding, and fructose feeding plus intraperitoneal fructose injection increased the activities of 6-phosphogluconate dehydrogenase and malic enzyme. Liver PDH activity was increased by fructose feeding, and was increased even more by fructose feeding and injection of fructose, but this was not associated with any changes in hepatic ATP concentrations

  9. Physiological and fermentation properties of Bacillus coagulans and a mutant lacking fermentative lactate dehydrogenase activity.

    Science.gov (United States)

    Su, Yue; Rhee, Mun Su; Ingram, Lonnie O; Shanmugam, K T

    2011-03-01

    Bacillus coagulans, a sporogenic lactic acid bacterium, grows optimally at 50-55 °C and produces lactic acid as the primary fermentation product from both hexoses and pentoses. The amount of fungal cellulases required for simultaneous saccharification and fermentation (SSF) at 55 °C was previously reported to be three to four times lower than for SSF at the optimum growth temperature for Saccharomyces cerevisiae of 35 °C. An ethanologenic B. coagulans is expected to lower the cellulase loading and production cost of cellulosic ethanol due to SSF at 55 °C. As a first step towards developing B. coagulans as an ethanologenic microbial biocatalyst, activity of the primary fermentation enzyme L-lactate dehydrogenase was removed by mutation (strain Suy27). Strain Suy27 produced ethanol as the main fermentation product from glucose during growth at pH 7.0 (0.33 g ethanol per g glucose fermented). Pyruvate dehydrogenase (PDH) and alcohol dehydrogenase (ADH) acting in series contributed to about 55% of the ethanol produced by this mutant while pyruvate formate lyase and ADH were responsible for the remainder. Due to the absence of PDH activity in B. coagulans during fermentative growth at pH 5.0, the l-ldh mutant failed to grow anaerobically at pH 5.0. Strain Suy27-13, a derivative of the l-ldh mutant strain Suy27, that produced PDH activity during anaerobic growth at pH 5.0 grew at this pH and also produced ethanol as the fermentation product (0.39 g per g glucose). These results show that construction of an ethanologenic B. coagulans requires optimal expression of PDH activity in addition to the removal of the LDH activity to support growth and ethanol production.

  10. Escherichia coli pyruvate dehydrogenase complex: particle masses of the complex and component enzymes measured by scanning transmission electron microscopy

    International Nuclear Information System (INIS)

    CaJacob, C.A.; Frey, P.A.; Hainfeld, J.F.; Wall, J.S.; Yang, H.

    1985-01-01

    Particle masses of the Escherichia coli pyruvate dehydrogenase (PDH) complex and its component enzymes have been measured by scanning transmission electron microscopy (STEM). The particle mass of PDH complex measured by STEM is 5.28 X 10(6) with a standard deviation of 0.40 X 10(6). The masses of the component enzymes are 2.06 X 10(5) for the dimeric pyruvate dehydrogenase (E1), 1.15 X 10(5) for dimeric dihydrolipoyl dehydrogenase (E3), and 2.20 X 10(6) for dihydrolipoyl transacetylase (E2), the 24-subunit core enzyme. STEM measurements on PDH complex incubated with excess E3 or E1 failed to detect any additional binding of E3 but showed that the complex would bind additional E1 under forcing conditions. The additional E1 subunits were bound too weakly to represent binding sites in an isolated or isolable complex. The mass measurements by STEM are consistent with the subunit composition 24:24:12 when interpreted in the light of the flavin content of the complex and assuming 24 subunits in the core enzyme (E2)

  11. Radiation-induced alterations in succinate dehydrogenase activity in the muscle of pigeon

    International Nuclear Information System (INIS)

    Gadhia, P.K.; Shah, V.C.

    1983-01-01

    The histochemical changes in succinate dehydrogenase were investigated in pectoralis major muscle of pigeon exposed to sub-lethal dose (400 rad) of γ-irradiation. Biochemical study was also carried out after 200, 300 and 400 rad of irradiation. In the present study the overall decrease in enzyme activity could be due to the structural and/or functional damage to mitochondria after treatment of pigeon to different sub-lethal doses of γ-irradiation. The significance of these results has been discussed with special reference to oxidative metabolism. (author)

  12. The activity of dehydrogenases in the uterus of C57B mice after X-irradiation and serotonin treatment

    International Nuclear Information System (INIS)

    Mazur, L.

    1978-01-01

    In C57B female mice, irradiated with 500 R and/or treated with serotonin (5-hydroxytryptamine), the activity of dehydrogenases in the uterus was studied on the fourth day of pregnancy. The reduction of 2,3,5-triphenyltetrazolium chloride to formazane by the uterine tissue was taken as the measure of such activity. The activity of dehydrogenases in the uterus of irradiated mice was distinctly lower than in non-irradiated controls. This activity was also depressed after serotonin treatment, the level of enzyme activity being dose-dependent. In females injected with serotonin and then irradiated, the activity of dehydrogenases was higher than in those irradiated only. The radioprotective effect was more pronounced in mice injected with serotonin alone on the third day of pregnancy i.e. shortly before irradiation, than in those injected on the second and the third day. (author)

  13. [Effects of Light Near-Infrared Radiation on Rats Assessed by Succinate Dehydrogenase Activity in Lymphocytes on Blood Smears].

    Science.gov (United States)

    Khunderyakova, N V; Zakharchenko, A V; Zakharchenko, M V; Muller, H; Fedotcheva, I; Kondrashova, M N

    2015-01-01

    Biological effects of light near infrared radiation (850 nm), with modulation acoustic frequency of 101 Hz, was studied. The study was conducted on rats, the effect was recorded by succinate dehydrogenase activity in lymphocytes on the blood smear after administration of the activating dose of adrenaline, which simulates the state of the organism in the early stages of the pathogenic effects (stress). A pronounced regulating effect of infrared radiation on the activity of succinate dehydrogenase in animals activated by adrenaline was shown. Infrared radiation has a normalizing effect reducing the degree of inhibition or activation of the enzyme induced by adrenaline and had no effect on the control animals. Thus, by modulating the activity of succinate dehydrogenase infrared radiation regulates energy production in the mitochondria supported by the most powerful oxidation substrate--succinic acid, which is especially pronounced under stress.

  14. Effects of Al(III and Nano-Al13 Species on Malate Dehydrogenase Activity

    Directory of Open Access Journals (Sweden)

    Rong Fu Chen

    2011-05-01

    Full Text Available The effects of different aluminum species on malate dehydrogenase (MDH activity were investigated by monitoring amperometric i-t curves for the oxidation of NADH at low overpotential using a functionalized multi-wall nanotube (MWNT modified glass carbon electrode (GCE. The results showed that Al(III and Al13 can activate the enzymatic activity of MDH, and the activation reaches maximum levels as the Al(III and Al13 concentration increase. Our study also found that the effects of Al(III and Al13 on the activity of MDH depended on the pH value and aluminum speciation. Electrochemical and circular dichroism spectra methods were applied to study the effects of nano-sized aluminum compounds on biomolecules.

  15. Effects of Al(III) and nano-Al13 species on malate dehydrogenase activity.

    Science.gov (United States)

    Yang, Xiaodi; Cai, Ling; Peng, Yu; Li, Huihui; Chen, Rong Fu; Shen, Ren Fang

    2011-01-01

    The effects of different aluminum species on malate dehydrogenase (MDH) activity were investigated by monitoring amperometric i-t curves for the oxidation of NADH at low overpotential using a functionalized multi-wall nanotube (MWNT) modified glass carbon electrode (GCE). The results showed that Al(III) and Al(13) can activate the enzymatic activity of MDH, and the activation reaches maximum levels as the Al(III) and Al(13) concentration increase. Our study also found that the effects of Al(III) and Al(13) on the activity of MDH depended on the pH value and aluminum speciation. Electrochemical and circular dichroism spectra methods were applied to study the effects of nano-sized aluminum compounds on biomolecules.

  16. Comparative study of the activity of lactate dehydrogenase (LDH) in different forms of disease

    International Nuclear Information System (INIS)

    Gonzalez Quesada, Jorge; Jorquera Cortez, Rodrigo; Rivera Alvarez, Sonia

    2007-01-01

    The activity of lactate dehydrogenase (LDH) was determined in the fluid gingival crevicular (FGC) from different sites of the anterior sector of the oral cavity in a clinically healthy subjects, and other with moderate gingivitis and with chronic severe generalized periodontists. Patients were treated and followed for three months, after the which has proceeded to make measurements of activity in the same sites discussed above. The results have showed statistically significant differences when comparing the activity of LDH in healthy individuals, and in other patients, treated by the pathology that presenting. On the other hand, were found without statistically significant differences between patients treated with clinically healthy subjects. The conclusion has been that the activity of LDH could be a quantitative marker for assessing cellular damage and evolution of treatment. (author) [es

  17. Decrease in the cytosolic NADP+-dependent isocitrate dehydrogenase activity through porcine sperm capacitation.

    Science.gov (United States)

    Katoh, Yuki; Tamba, Michiko; Matsuda, Manabu; Kikuchi, Kazuhiro; Okamura, Naomichi

    2018-02-26

    In order to understand the molecular mechanisms involved in the sperm capacitation, we have identified the proteins tyrosine-phosphorylated during the capacitation especially in conjunction with the regulation of the levels of reactive oxygen species (ROS) in sperm. In the present study, the effects of the tyrosine phosphorylation of cytosolic NADP + -dependent isocitrate dehydrogenase (IDPc) on its catalytic activity and on the levels of ROS in sperm have been studied. The tyrosine phosphorylated IDPc showed a significantly lowered enzymatic activity. The immunocytochemical analyses using the highly specific antisera against IDPc revealed that IDPc was mainly localized to the principal piece of the porcine sperm flagellum. As IDPc is one of the major NADPH regenerating enzymes in porcine sperm, it is strongly suggested that the decrease in IDPc activity is involved in the increased levels of ROS, which results in the induction of hyperactivated flagellar movement and capacitation. Copyright © 2018 Elsevier Inc. All rights reserved.

  18. Effect of different mulch materials on the soil dehydrogenase activity (DHA) in an organic pepper crop

    Science.gov (United States)

    Moreno, Marta M.; Peco, Jesús; Campos, Juan; Villena, Jaime; González, Sara; Moreno, Carmen

    2016-04-01

    The use biodegradable materials (biopolymers of different composition and papers) as an alternative to conventional mulches has increased considerably during the last years mainly for environmental reason. In order to assess the effect of these materials on the soil microbial activity during the season of a pepper crop organically grown in Central Spain, the soil dehydrogenase activity (DHA) was measured in laboratory. The mulch materials tested were: 1) black polyethylene (PE, 15 μm); black biopolymers (15 μm): 2) Mater-Bi® (corn starch based), 3) Sphere 4® (potato starch based), 4) Sphere 6® (potato starch based), 5) Bioflex® (polylactic acid based), 6) Ecovio® (polylactic acid based), 7) Mimgreen® (black paper, 85 g/m2). A randomized complete block design with four replications was adopted. The crop was drip irrigated following the water demand of each treatment. Soil samples (5-10 cm depth) under the different mulches were taken at different dates (at the beginning of the crop cycle and at different dates throughout the crop season). Additionally, samples of bare soil in a manual weeding and in an untreated control were taken. The results obtained show the negative effect of black PE on the DHA activity, mainly as result of the higher temperature reached under the mulch and the reduction in the gas interchange between the soil and the atmosphere. The values corresponding to the biodegradable materials were variable, although highlighting the low DHA activity observed under Bioflex®. In general, the uncovered treatments showed higher values than those reached under mulches, especially in the untreated control. Keywords: mulch, biodegradable, biopolymer, paper, dehydrogenase activity (DHA). Acknowledgements: the research was funded by Project RTA2011-00104-C04-03 from the INIA (Spanish Ministry of Economy and Competitiveness).

  19. High performance liquid chromatography method for the determination of cinnamyl alcohol dehydrogenase activity in soybean roots.

    Science.gov (United States)

    dos Santos, W D; Ferrarese, Maria de Lourdes Lucio; Ferrarese-Filho, O

    2006-01-01

    This study proposes a simple, quick and reliable method for determining the cinnamyl alcohol dehydrogenase (CAD; EC 1.1.1.195) activity in soybean (Glycine max L. Merr.) roots using reversed-phase high performance liquid chromatography (RP-HPLC). The method includes a single extraction of the tissue and conduction of the enzymatic reaction at 30 degrees C with cinnamaldehydes (coniferyl or sinapyl), substrates of CAD. Disappearance of the substrates in the reaction mixture is monitored at 340 nm (for coniferaldehyde) or 345 nm (for sinapaldehyde) by isocratic elution with methanol/acetic acid through a GLC-ODS (M) column. This HPLC technique furnishes a rapid and reliable measure of cinnamaldehyde substrates, and may be used as an alternative tool to analyze CAD activity in enzyme preparation without previous purification.

  20. Effect of ionizing radiation on the colour and activity of lactate dehydrogenase of pork

    International Nuclear Information System (INIS)

    Dvorak, P.; Salplachta, J.; Grolichova, M.

    2006-01-01

    The most significant sensory and quality characteristic of meat is colour. The effect of irradiation of pork was studied in relation to color changes. Samples of M. longissimus lumborum et thoracic were obtained from the pork carcasses 24 h post mortem. Samples were irradiated using a 60 Co source, at dose of 2.5 and 5 kGy; dose rate of 2.86 kGy/h. Unirradiated controls were stored in the same condition as irradiated samples. Measurement of colour was realised with portable spectrophotometer Superchroma S-Spex in CIELAB system. The colour of a freshly cut interior surface of control and irradiated pork was measured before and after irradiation. L * and b * values of controls and irradiated pork did not change after irradiation. The a * values (red colour) of irradiated pork were significantly higher than unirradiated. The activity of lactate dehydrogenase of pork was measured after irradiation. The activity did not change after irradiation. (authors)

  1. Pronounced between-subject and circadian variability in thymidylate synthase and dihydropyrimidine dehydrogenase enzyme activity in human volunteers

    NARCIS (Netherlands)

    Jacobs, Bart A W; Deenen, Maarten J; Pluim, Dick; van Hasselt, J G Coen; Krähenbühl, Martin D; van Geel, Robin M J M; de Vries, Niels; Rosing, Hilde; Meulendijks, Didier; Burylo, Artur M; Cats, Annemieke; Beijnen, Jos H; Huitema, Alwin D R; Schellens, Jan H M

    AIMS: The enzymatic activity of dihydropyrimidine dehydrogenase (DPD) and thymidylate synthase (TS) are important for the tolerability and efficacy of the fluoropyrimidine drugs. In the present study, we explored between-subject variability (BSV) and circadian rhythmicity in DPD and TS activity in

  2. The activity state of the branched-chain 2-oxo acid dehydrogenase complex in rat tissues.

    Science.gov (United States)

    Wagenmakers, A J; Schepens, J T; Veldhuizen, J A; Veerkamp, J H

    1984-05-15

    An assay is described to define the proportion of the branched-chain 2-oxo acid dehydrogenase complex that is present in the active state in rat tissues. Activities are measured in homogenates in two ways: actual activities, present in tissues, by blocking both the kinase and phosphatase of the enzyme complex during homogenization, preincubation, and incubation with 1-14C-labelled branched-chain 2-oxo acid, and total activities by blocking only the kinase during the 5 min preincubation (necessary for activation). The kinase is blocked by 5 mM-ADP and absence of Mg2+ and the phosphatase by the simultaneous presence of 50 mM-NaF. About 6% of the enzyme is active in skeletal muscle of fed rats, 7% in heart, 20% in diaphragm, 47% in kidney, 60% in brain and 98% in liver. An entirely different assay, which measures activities in crude tissue extracts before and after treatment with a broad-specificity protein phosphatase, gave similar results for heart, liver and kidney. Advantages of our assay with homogenates are the presence of intact mitochondria, the simplicity, the short duration and the high sensitivity. The actual activities measured indicate that the degradation of branched-chain 2-oxo acids predominantly occurs in liver and kidney and is limited in skeletal muscle in the fed state.

  3. A new bianthron glycoside as inhibitor of Trypanosoma cruzi glyceraldehyde 3-phosphate dehydrogenase activity

    International Nuclear Information System (INIS)

    Macedo, Edangelo M.S. de; Silva, Maria G.V.; Wiggers, Helton J.; Montanari, Carlos A.; Braz-Filho, Raimundo; Andricopulo, Adriano D.

    2009-01-01

    A phytochemical investigation of the ethanolic extract of stalks of Senna martiana Benth. (Leguminoseae), native specie of northeast Brazil, resulted in the isolation and spectroscopic characterization of a new bianthrone glycoside, martianine 1 (10,10'-il-chrysophanol-10-oxi- 10,10'-bi-glucosyl). Its identification was established by HRMS, IR and 2D NMR experiments. The evaluation of martianine trypanocidal activity was carried out against gliceraldehyde 3-phosphate dehydrogenase enzyme from Trypanosoma cruzi. Its inhibitory constant (K i ) is in the low micromolar concentration and it was determined by isothermal titration calorimetry to be 27.3 +-2.47 μmol L -1 . The non-competitive mechanism is asserted to be putative of the mode of action martianine displays against T. cruzi GAPDH. Results show that martianine has a great potential to become new lead molecule by inhibiting this key enzyme and for the development of new drugs against Chagas disease. (author)

  4. EFFECTS OF AMARANTHS’ SEEDS ON DEHYDROGENASE ACTIVITY AND GASES EMISSION IN METHANOGENIC BIOREACTORS

    Directory of Open Access Journals (Sweden)

    Victor COVALIOV

    2015-12-01

    Full Text Available The influence of amaranths‘ seeds as the source of squalene on the dehydrogenase activity and efficiency of methane production were investigated in methanogenic bench-scale (5000 ml bioreactors used to treat the mixture of distillery wastes and farmyard manure. The adding of amaranth seeds to the methanogenic bioreactor has an inhibitory effect on the dehydrogenase activity and stimulates the process of methanogenesis. Dehydrogenase activity decreased with the increase of doses of squalene and its trend had a close connection with doses (R2=0.77-0.78. The methane content in the total amount of gases is 65.3-71.3% in a bioreactor with the additive of amaranth seeds in a dose of 50 mg l-1, which is 22.1% higher than in the the control bioreactor without additives. The increase in squalene concentration higher than 0.0005% is not rational because its stimulating effect on the methanogenic process decreases. Anaerobic digestion of alcohol distillery industry wastes with manure is a complex nonlinear time-varying microbiological process. Dehydrogenase activity trends in the experiment are described by the power function for 5 hours observations and by the logarithmic function for 120 hours of observations. Trends of CH4 are described by the polynomial function in all periods of testing. Correlation coefficients are 0.37 and 0.70 for CH4 after 5 and 120 hours of the anaerobic digestion. Dehydrogenase activity is in the close negative connection with the amount of gases, including methane. Correlation analysis between dehydrogenase activity and the release of gases has revealed the moderate and strongly negative link during 24 hours after the start of the experiment.EFECTUL SEMINŢELOR DE AMARANT ASUPRA ACTIVITĂŢII DEHIDROGENAZEI ŞI EMISIEI GAZELOR ÎN BIOREACTOARELE METANOGENEÎn bioreactoare metanogene unite consecutiv, cu volum de 5000 ml, utilizate pentru tratarea amestecului de borhot de la distilarea alcoolului cu gunoi de grajd, a fost

  5. Identification of Electronic and Structural Descriptors of Adenosine Analogues Related to Inhibition of Leishmanial Glyceraldehyde-3-Phosphate Dehydrogenase

    Directory of Open Access Journals (Sweden)

    Norka B. H. Lozano

    2013-04-01

    Full Text Available Quantitative structure–activity relationship (QSAR studies were performed in order to identify molecular features responsible for the antileishmanial activity of 61 adenosine analogues acting as inhibitors of the enzyme glyceraldehyde 3-phosphate dehydrogenase of Leishmania mexicana (LmGAPDH. Density functional theory (DFT was employed to calculate quantum-chemical descriptors, while several structural descriptors were generated with Dragon 5.4. Variable selection was undertaken with the ordered predictor selection (OPS algorithm, which provided a set with the most relevant descriptors to perform PLS, PCR and MLR regressions. Reliable and predictive models were obtained, as attested by their high correlation coefficients, as well as the agreement between predicted and experimental values for an external test set. Additional validation procedures were carried out, demonstrating that robust models were developed, providing helpful tools for the optimization of the antileishmanial activity of adenosine compounds.

  6. Glyceraldehyde-3-phosphate dehydrogenase from Chironomidae showed differential activity towards metals.

    Science.gov (United States)

    Chong, Isaac K W; Ho, Wing S

    2013-09-01

    Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is known to interact with different biomolecules and was implicated in many novel cellular activities including programmed cell death, nuclear RNA transport unrelated to the commonly known carbohydrate metabolism. We reported here the purification of GAPDH from Chironomidae larvae (Insecta, Diptera) that showed different biologic activity towards heavy metals. It was inhibited by copper, cobalt nickel, iron and lead but was activated by zinc. The GAPDH was purified by ammonium sulphate fractionation and Chelating Sepharose CL-6B chromatography followed by Blue Sepharose CL-6B chromatography. The 150-kDa tetrameric GAPDH showed optimal activity at pH 8.5 and 37°C. The multiple alignment of sequence of the Chironomidae GAPDH with other known species showed 78 - 88% identity to the conserved regions of the GADPH. Bioinformatic analysis unveils substantial N-terminal sequence similarity of GAPDH of Chironomidae larvae to mammalian GADPHs. However, the GADPH of Chironomidae larvae showed different biologic activities and cytotoxicity towards heavy metals. The GAPDH enzyme would undergo adaptive molecular changes through binding at the active site leading to higher tolerance to heavy metals.

  7. Corneal aldehyde dehydrogenase and glutathione S-transferase activity after excimer laser keratectomy in guinea pigs.

    Science.gov (United States)

    Bilgihan, K; Bilgihan, A; Hasanreisoğlu, B; Turkozkan, N

    1998-03-01

    The free radical balance of the eye may be changed by excimer laser keratectomy. Previous studies have demonstrated that excimer laser keratectomy increases the corneal temperature, decreases the superoxide dismutase activity of the aqueous, and induces lipid peroxidation in the superficial corneal stroma. Aldehyde dehydrogenase (ALDH) and glutathione S-transferase (GST) are known to play an important role in corneal metabolism, particularly in detoxification of aldehydes, which are generated from free radical reactions. In three groups of guinea pigs mechanical corneal de-epithelialisation was performed in group I, superficial corneal photoablation in group II, and deep corneal photoablation in group III, and the corneal ALDH and GST activities measured after 48 hours. The mean ALDH and GST activities of group I and II showed no differences compared with the controls (p > 0.05). The corneal ALDH activities were found to be significantly decreased (p < 0.05) and GST activities increased (p < 0.05) in group III. These results suggest that excimer laser treatment of high myopia may change the ALDH and GST activities, metabolism, and free radical balance of the cornea.

  8. Vitality Improvement of the Mediterranean Fruit Fly, Ceratitis capitata Wied 1- Measured by using dehydrogenase Enzyme Activities

    International Nuclear Information System (INIS)

    Salama, M.S.; Shoman, A.A.; Elbermawy, S.M.; Abul Yazid, I.

    2000-01-01

    The present study searches for the improvement vitality of the Mediterranean fruit fly, Ceratitis capitata Wied. Through the induction of a specific variance (mutation) in the genetic material. Several types of treatments that were thought to cause this mutation were used, as IGR's, temperature, formaldehyde, colchicine, alcohols, several types of larval rearing media and gamma-rays. Generally, the activities of the energy enzymes alpha-glycerophosphate dehydrogenase (alpha-GPDH) enzyme lactate dehydrogenase (LDH) enzyme and malate dehydrogenase (MDH) enzyme, when used as a direct measure for the fly vitality, increased due to treatments of the egg stage by the previously mentioned treatments specially by the usage of rice hulls in the larval rearing medium alone or followed by irradiation of the pupal stage with 90 Gy

  9. Exercise training induces similar elevations in the activity of oxoglutarate dehydrogenase and peak oxygen uptake in the human quadriceps muscle

    DEFF Research Database (Denmark)

    Blomstrand, Eva; Krustrup, Peter; Søndergaard, Hans

    2011-01-01

    During exercise involving a small muscle mass, peak oxygen uptake is thought to be limited by peripheral factors, such as the degree of oxygen extraction from the blood and/or mitochondrial oxidative capacity. Previously, the maximal activity of the Krebs cycle enzyme oxoglutarate dehydrogenase has...

  10. Reaction rate studies of glucose-6-phosphate dehydrogenase activity in sections of rat liver using four tetrazolium salts

    NARCIS (Netherlands)

    Butcher, R. G.; van Noorden, C. J.

    1985-01-01

    The reaction rate of glucose-6-phosphate dehydrogenase activity in liver sections from fed and starved rats has been monitored by the continuous measurement at 37 degrees C of the reaction product as it is formed using scanning and integrating microdensitometry. Control media lacked either substrate

  11. Functional assignment of Glu386 and Arg388 in the active site of l-galactono-¿-lactone dehydrogenase

    NARCIS (Netherlands)

    Leferink, N.G.H.; Jose, M.D.F.; Berg, van den W.A.M.; Berkel, van W.J.H.

    2009-01-01

    The flavoenzyme l-galactono-¿-lactone dehydrogenase (GALDH) catalyzes the terminal step of vitamin C biosynthesis in plants. Little is known about the catalytic mechanism of GALDH and related aldonolactone oxidoreductases. Here we identified an essential Glu–Arg pair in the active site of GALDH from

  12. Determination of glutamate dehydrogenase activity and its kinetics in mouse tissues using metabolic mapping (quantitative enzyme histochemistry)

    NARCIS (Netherlands)

    Botman, Dennis; Tigchelaar, Wikky; van Noorden, Cornelis J. F.

    2014-01-01

    Glutamate dehydrogenase (GDH) catalyses the reversible conversion of glutamate into α-ketoglutarate with the concomitant reduction of NAD(P)(+) to NAD(P)H or vice versa. GDH activity is subject to complex allosteric regulation including substrate inhibition. To determine GDH kinetics in situ, we

  13. Synthesis and antifungal activity of nicotinamide derivatives as succinate dehydrogenase inhibitors.

    Science.gov (United States)

    Ye, Yong-Hao; Ma, Liang; Dai, Zhi-Cheng; Xiao, Yu; Zhang, Ying-Ying; Li, Dong-Dong; Wang, Jian-Xin; Zhu, Hai-Liang

    2014-05-07

    Thirty-eight nicotinamide derivatives were designed and synthesized as potential succinate dehydrogenase inhibitors (SDHI) and precisely characterized by (1)H NMR, ESI-MS, and elemental analysis. The compounds were evaluated against two phytopathogenic fungi, Rhizoctonia solani and Sclerotinia sclerotiorum, by mycelia growth inhibition assay in vitro. Most of the compounds displayed moderate activity, in which, 3a-17 exhibited the most potent antifungal activity against R. solani and S. sclerotiorum with IC50 values of 15.8 and 20.3 μM, respectively, comparable to those of the commonly used fungicides boscalid and carbendazim. The structure-activity relationship (SAR) of nicotinamide derivatives demonstrated that the meta-position of aniline was a key position contributing to the antifungal activity. Inhibition activities against two fungal SDHs were tested and achieved the same tendency with the data acquired from in vitro antifungal assay. Significantly, 3a-17 was demonstrated to successfully suppress disease development in S. sclerotiorum infected cole in vivo. In the molecular docking simulation, sulfur and chlorine of 3a-17 were bound with PHE291 and PRO150 of the SDH homology model, respectively, which could explain the probable mechanism of action between the inhibitory and target protein.

  14. Formation of W(3)A(1) electron-transferring flavoprotein (ETF) hydroquinone in the trimethylamine dehydrogenase x ETF protein complex.

    Science.gov (United States)

    Jang, M H; Scrutton, N S; Hille, R

    2000-04-28

    The electron-transferring flavoprotein (ETF) from Methylophilus methylotrophus (sp. W(3)A(1)) exhibits unusual oxidation-reduction properties and can only be reduced to the level of the semiquinone under most circumstances (including turnover with its physiological reductant, trimethylamine dehydrogenase (TMADH), or reaction with strong reducing reagents such as sodium dithionite). In the present study, we demonstrate that ETF can be reduced fully to its hydroquinone form both enzymatically and chemically when it is in complex with TMADH. Quantitative titration of the TMADH x ETF protein complex with sodium dithionite shows that a total of five electrons are taken up by the system, indicating that full reduction of ETF occurs within the complex. The results indicate that the oxidation-reduction properties of ETF are perturbed upon binding to TMADH, a conclusion further supported by the observation of a spectral change upon formation of the TMADH x ETF complex that is due to a change in the environment of the FAD of ETF. The results are discussed in the context of ETF undergoing a conformational change during formation of the TMADH x ETF electron transfer complex, which modulates the spectral and oxidation-reduction properties of ETF such that full reduction of the protein can take place.

  15. QSAR study on the antimalarial activity of Plasmodium falciparum dihydroorotate dehydrogenase (PfDHODH) inhibitors.

    Science.gov (United States)

    Hou, X; Chen, X; Zhang, M; Yan, A

    2016-01-01

    Plasmodium falciparum, the most fatal parasite that causes malaria, is responsible for over one million deaths per year. P. falciparum dihydroorotate dehydrogenase (PfDHODH) has been validated as a promising drug development target for antimalarial therapy since it catalyzes the rate-limiting step for DNA and RNA biosynthesis. In this study, we investigated the quantitative structure-activity relationships (QSAR) of the antimalarial activity of PfDHODH inhibitors by generating four computational models using a multilinear regression (MLR) and a support vector machine (SVM) based on a dataset of 255 PfDHODH inhibitors. All the models display good prediction quality with a leave-one-out q(2) >0.66, a correlation coefficient (r) >0.85 on both training sets and test sets, and a mean square error (MSE) antimalarial activity. The models are capable of predicting inhibitors' antimalarial activity and the molecular descriptors for building the models could be helpful in the development of new antimalarial drugs.

  16. Direct electron transfer-based bioanodes for ethanol biofuel cells using PQQ-dependent alcohol and aldehyde dehydrogenases

    International Nuclear Information System (INIS)

    Aquino Neto, Sidney; Suda, Emily L.; Xu, Shuai; Meredith, Matthew T.; De Andrade, Adalgisa R.; Minteer, Shelley D.

    2013-01-01

    This paper compares the performance of a DET (direct electron transfer) bioanode containing both PQQ-ADH (pyrroloquinoline quinone-dependent alcohol dehydrogenase) and PQQ-AldDH (PQQ-dependent aldehyde dehydrogenase) immobilized onto different modified electrode surfaces employing either a tetrabutylammonium (TBAB)-modified Nafion ® membrane polymer or polyamidoamine (PAMAM) dendrimers for the enzyme immobilization. The electrochemical characterization showed that the prepared bioelectrodes were able to undergo DET onto glassy carbon surface in the presence as well as the absence of multi-walled carbon nanotubes (MWCNTs); also, in the latter case a relevant shift in the oxidation peak of about 180 mV vs. saturated calomel electrode (SCE) was observed. A very similar redox potential was achieved with the self-assembled bioelectrode prepared onto modified-gold surfaces with dendrimers, indicating that both methodologies provide an environment that enables the PQQ-enzymes to undergo DET. The biofuel cell tests confirmed the ease of the DET process and the enhanced performance in the presence of the carbon nanotubes. Considering the bioanodes prepared with PAMAM dendrimers, the power density values vary from 19.4 μW cm −2 without MWCNTs to 25.7 μW cm −2 in the presence of MWCNTs. Similarly, with the bioanodes prepared with the TBAB-modified-Nafion ® polymer, the results indicate power densities of 27.9 and 38.4 μW cm −2 respectively. These electrode modifications represent effective methods for immobilization and direct electrical connection of quinohemoproteins to electrode surfaces.

  17. Lactate Dehydrogenase and Oxidative Stress Activity in Primary Open-Angle Glaucoma Aqueous Humour

    Directory of Open Access Journals (Sweden)

    Predrag Jovanović

    2010-02-01

    Full Text Available Lactate dehydrogenase (LDH and lactate are some of the hypoxy biochemical parameters. Extracellular activity of this enzyme increases under the condition of oxidative stress, since the cell integrity can be disrupted during the lipid peroxidation process. Subsequently that leads to the increase level of the lactic acid and lactic acid salts. The objective of this investigation is establishing the level of LDH, LDH1 (HBDH and the lactate concentration in aqueous humour in patients with primary open-angle glaucoma.Biochemical analysis have been made by enzymatic-colometric method (lactate and UV-kinetic method (LDH and HBDH in aqueous humour of 30 patients (42 eyes with primary open-angle glaucoma (POAG and 30 patients (40 eyes with cataract (the control group.The increased values of lactate and the activity of LDH and HBDH enzyme in aqueous humour of POAG patients in correlation with the control group are the results not only of oxidative stress but also of hypoxy and the mitochondry oxidative function (p<0,001.The increased activity of the examined biochemical parameters in the aqueous humour of the POAG patients points to the fact that other mechanisms, besides IOP, have a role in glaucoma pathogenesis.

  18. Antimalarial activity of potential inhibitors of Plasmodium falciparum lactate dehydrogenase enzyme selected by docking studies.

    Directory of Open Access Journals (Sweden)

    Julia Penna-Coutinho

    Full Text Available The Plasmodium falciparum lactate dehydrogenase enzyme (PfLDH has been considered as a potential molecular target for antimalarials due to this parasite's dependence on glycolysis for energy production. Because the LDH enzymes found in P. vivax, P. malariae and P. ovale (pLDH all exhibit ∼90% identity to PfLDH, it would be desirable to have new anti-pLDH drugs, particularly ones that are effective against P. falciparum, the most virulent species of human malaria. Our present work used docking studies to select potential inhibitors of pLDH, which were then tested for antimalarial activity against P. falciparum in vitro and P. berghei malaria in mice. A virtual screening in DrugBank for analogs of NADH (an essential cofactor to pLDH and computational studies were undertaken, and the potential binding of the selected compounds to the PfLDH active site was analyzed using Molegro Virtual Docker software. Fifty compounds were selected based on their similarity to NADH. The compounds with the best binding energies (itraconazole, atorvastatin and posaconazole were tested against P. falciparum chloroquine-resistant blood parasites. All three compounds proved to be active in two immunoenzymatic assays performed in parallel using monoclonals specific to PfLDH or a histidine rich protein (HRP2. The IC(50 values for each drug in both tests were similar, were lowest for posaconazole (<5 µM and were 40- and 100-fold less active than chloroquine. The compounds reduced P. berghei parasitemia in treated mice, in comparison to untreated controls; itraconazole was the least active compound. The results of these activity trials confirmed that molecular docking studies are an important strategy for discovering new antimalarial drugs. This approach is more practical and less expensive than discovering novel compounds that require studies on human toxicology, since these compounds are already commercially available and thus approved for human use.

  19. Ethanol production by anaerobic thermophilic bacteria: regulation of lactate dehydrogenase activity in Clostridium thermohydrosulfuricum

    Energy Technology Data Exchange (ETDEWEB)

    Germain, P; Toukourou, F; Donaduzzi, L

    1986-07-01

    The enzyme lactate dehydrogenase (LDH) in Clostridium thermohydrosulfuricum is controlled by the type and the concentration of the substrate. In batch fermentations an increase of the initial concentration of glucose leads to an increase in the activity of LDH. This increase in activity is related to the accumulation of fructose 1,6-diphosphate (F 1,6-DP), an intermediate of the Embden-Meyerhof-Parnas (EMP) pathway, which stimulates the enzyme by increasing its affinity for pyruvate and NADH. The Ksub(m) values of LDH for pyruvate and NADH, which are 2.5 x 10/sup -3/ M and 9.1 x 10/sup -5/ M respectively in absence of F 1,6-DP, fall considerably in the presence of this substrate. In presence of 0.2 mM of F 1,6-DP we observed a Ksub(m) of 3.3 x 10/sup -4/ M for pyruvate and 4.1 x 10/sup -5/ M for NADH.

  20. Stability and activity of lactate dehydrogenase on biofunctional layers deposited by activated vapor silanization (AVS) and immersion silanization (IS)

    Science.gov (United States)

    Calvo, Jorge Nieto-Márquez; Elices, Manuel; Guinea, Gustavo V.; Pérez-Rigueiro, José; Arroyo-Hernández, María

    2017-09-01

    The interaction between surfaces and biological elements, in particular, proteins is critical for the performance of biomaterials and biosensors. This interaction can be controlled by modifying the surface in a process known as biofunctionalization. In this work, the enzyme lactate dehydrogenase (LDH) is used to study the stability of the interaction between a functional protein and amine-functionalized surfaces. Two different functionalization procedures were compared: Activated Vapor Silanization (AVS) and Immersion Silanization (IS). Adsorption kinetics is shown to follow the Langmuir model for AVS-functionalized samples, while IS-functionalized samples show a certain instability if immersed in an aqueous medium for several hours. In turn, the enzymatic activity of LDH is preserved for longer times by using glutaraldehyde as crosslinker between the AVS biofunctional surface and the enzyme.

  1. Subcellular Characterization of Porcine Oocytes with Different Glucose-6-phosphate Dehydrogenase Activities

    Directory of Open Access Journals (Sweden)

    Bo Fu

    2015-12-01

    Full Text Available The in vitro maturation (IVM efficiency of porcine embryos is still low because of poor oocyte quality. Although brilliant cresyl blue positive (BCB+ oocytes with low glucose-6-phosphate dehydrogenase (G6PDH activity have shown superior quality than BCB negative (− oocytes with high G6PDH activity, the use of a BCB staining test before IVM is still controversial. This study aimed to shed more light on the subcellular characteristics of porcine oocytes after selection using BCB staining. We assessed germinal vesicle chromatin configuration, cortical granule (CG migration, mitochondrial distribution, the levels of acetylated lysine 9 of histone H3 (AcH3K9 and nuclear apoptosis features to investigate the correlation between G6PDH activity and these developmentally related features. A pattern of chromatin surrounding the nucleoli was seen in 53.0% of BCB+ oocytes and 77.6% of BCB+ oocytes showed peripherally distributed CGs. After IVM, 48.7% of BCB+ oocytes had a diffused mitochondrial distribution pattern. However, there were no significant differences in the levels of AcH3K9 in the nuclei of blastocysts derived from BCB+ and BCB− oocytes; at the same time, we observed a similar incidence of apoptosis in the BCB+ and control groups. Although this study indicated that G6PDH activity in porcine oocytes was correlated with several subcellular characteristics such as germinal vesicle chromatin configuration, CG migration and mitochondrial distribution, other features such as AcH3K9 level and nuclear apoptotic features were not associated with G6PDH activity and did not validate the BCB staining test. In using this test for selecting porcine oocytes, subcellular characteristics such as the AcH3K9 level and apoptotic nuclear features should also be considered. Adding histone deacetylase inhibitors or apoptosis inhibitors into the culture medium used might improve the efficiency of IVM of BCB+ oocytes.

  2. Urinary Lactate Dehydrogenase Activity and Its Isozyme Patterns in Kawasaki Disease

    Directory of Open Access Journals (Sweden)

    Yoichi Kawamura

    2017-01-01

    Full Text Available Abnormal urinary findings, such as sterile pyuria, proteinuria, and microscopic hematuria, are often seen in the acute phase of Kawasaki disease (KD. We investigated the potential significance of urinary lactate dehydrogenase (U-LDH activity and its isozyme patterns in KD. Total U-LDH activity and its isozymes (U-LDH1-5 levels were compared among 120 patients with KD, 18 patients with viral infection (VI, and 43 patients with upper urinary tract infection (UTI and additionally compared between intravenous immunoglobulin (IVIG responders (n=89 and nonresponders (n=31 with KD. Total U-LDH activity was higher in KD (35.4±4.8 IU/L, P<0.05 and UTI patients (66.0±8.0 IU/L, P<0.01 than in VI patients (17.0±6.2 IU/L. In the isozyme pattern analysis, KD patients had high levels of U-LDH1 and U-LDH2, while UTI patients had high levels of U-LDH3, U-LDH4, and U-LDH5. Furthermore, IVIG nonresponders of KD had significantly higher levels of total U-LDH activity (45.1±4.7 IU/L, P<0.05, especially U-LDH1 and U-LDH2 (P<0.05, than IVIG responders (32.0±2.8 IU/L. KD patients have increased levels of total U-LDH activity, especially U-LDH-1 and U-LDH2, indicating a unique pattern of U-LDH isozymes different from that in UTI patients.

  3. Binding of the human "electron transferring flavoprotein" (ETF) to the medium chain acyl-CoA dehydrogenase (MCAD) involves an arginine and histidine residue.

    Science.gov (United States)

    Parker, Antony R

    2003-10-01

    The interaction between the "electron transferring flavoprotein" (ETF) and medium chain acyl-CoA dehydrogenase (MCAD) enables successful flavin to flavin electron transfer, crucial for the beta-oxidation of fatty acids. The exact biochemical determinants for ETF binding to MCAD are unknown. Here we show that binding of human ETF, to MCAD, was inhibited by 2,3-butanedione and diethylpyrocarbonate (DEPC) and reversed by incubation with free arginine and hydroxylamine respectively. Spectral analyses of native ETF vs modified ETF suggested that flavin binding was not affected and that the loss of ETF activity with MCAD involved modification of one ETF arginine residue and one ETF histidine residue respectively. MCAD and octanoyl-CoA protected ETF against inactivation by both 2,3-butanedione and DEPC indicating that the arginine and histidine residues are present in or around the MCAD binding site. Comparison of exposed arginine and histidine residues among different ETF species, however, indicates that arginine residues are highly conserved but that histidine residues are not. These results lead us to conclude that this single arginine residue is essential for the binding of ETF to MCAD, but that the single histidine residue, although involved, is not.

  4. Hypoxia and anoxia effects on alcohol dehydrogenase activity and hemoglobin content in Chironomus riparius Meigen, 1804

    Directory of Open Access Journals (Sweden)

    Valentina Grazioli

    2016-02-01

    Full Text Available The metabolic effects of low oxygen content on alcohol-dehydrogenase (ADH activity and hemoglobin (Hb concentration were investigated in IV-instar larvae of Chironomus riparius (Diptera: Chironomidae from an Italian stream. Two series of short-term (48 h experiments were carried out: exposure to (1 progressive hypoxia (95 to 5% of oxygen saturation and (2 anoxia (at <5% of oxygen saturation. In (1, Hb amount increased with increasing oxygen depletion up to a critical value of oxygenation (about 70% of oxygen saturation. Below this percentage, the Hb amount declined to values comparable with those present in the control. The respiration rate (R remained almost constant at oxygen saturation >50% and decreased significantly only after 48 h of treatment (= <5% of oxygen saturation reaching values <100 mmolO2 gAFDW-1 h-1. ADH activity showed two phases of growth, within the first 14 h and over 18 h of exposure. Overall, we inferred that i Hb might function as short-term oxygen storage, enabling animals to delay the on-set of anaerobiosis; and ii alcoholic fermentation co-occurs for a short time with aerobic respiration, becoming the prevalent metabolic pathway below 5% of oxygen saturation (<1 mg L-1. These considerations were supported also by results from anoxia exposure (2. In such condition, larvae were visibly stressed, becoming immobile after few minutes of incubation, and ADH reached higher values than in the hypoxia treatment (2.03±0.15 UADH mg prot-1. Overall, this study showed a shift from aerobic to anaerobic activity in C. riparius larvae exposed to poorly oxygenated water with an associated alteration of ADH activity and the Hb amount. Such metabolites might be valid candidate biomarkers for the environmental monitoring of running waters.

  5. Mannitol transport and mannitol dehydrogenase activities are coordinated in Olea europaea under salt and osmotic stresses.

    Science.gov (United States)

    Conde, Artur; Silva, Paulo; Agasse, Alice; Conde, Carlos; Gerós, Hernâni

    2011-10-01

    The intracellular accumulation of organic compatible solutes functioning as osmoprotectants, such as polyols, is an important response mechanism of several plants to drought and salinity. In Olea europaea a mannitol transport system (OeMaT1) was previously characterized as a key player in plant response to salinity. In the present study, heterotrophic sink models, such as olive cell suspensions and fruit tissues, and source leaves were used for analytical, biochemical and molecular studies. The kinetic parameters of mannitol dehydrogenase (MTD) determined in cells growing in mannitol, at 25°C and pH 9.0, were as follows: K(m), 54.5 mM mannitol; and V(max), 0.47 μmol h⁻¹ mg⁻¹ protein. The corresponding cDNA was cloned and named OeMTD1. OeMTD1 expression was correlated with MTD activity, OeMaT1 expression and carrier-mediated mannitol transport in mannitol- and sucrose-grown cells. Furthermore, sucrose-grown cells displayed only residual OeMTD activity, even though high levels of OeMTD1 transcription were observed. There is evidence that OeMTD is regulated at both transcriptional and post-transcriptional levels. MTD activity and OeMTD1 expression were repressed after Na+, K+ and polyethylene glycol (PEG) treatments, in both mannitol- and sucrose-grown cells. In contrast, salt and drought significantly increased mannitol transport activity and OeMaT1 expression. Taken together, these studies support that olive trees cope with salinity and drought by coordinating mannitol transport with intracellular metabolism.

  6. Purification and characterization of xylitol dehydrogenase with l-arabitol dehydrogenase activity from the newly isolated pentose-fermenting yeast Meyerozyma caribbica 5XY2.

    Science.gov (United States)

    Sukpipat, Wiphat; Komeda, Hidenobu; Prasertsan, Poonsuk; Asano, Yasuhisa

    2017-01-01

    Meyerozyma caribbica strain 5XY2, which was isolated from an alcohol fermentation starter in Thailand, was found to catabolize l-arabinose as well as d-glucose and d-xylose. The highest production amounts of ethanol from d-glucose, xylitol from d-xylose, and l-arabitol from l-arabinose were 0.45 g/g d-glucose, 0.60 g/g d-xylose, and 0.61 g/g l-arabinose with 21.7 g/L ethanol, 20.2 g/L xylitol, and 30.3 g/l l-arabitol, respectively. The enzyme with l-arabitol dehydrogenase (LAD) activity was purified from the strain and found to exhibit broad specificity to polyols, such as xylitol, d-sorbitol, ribitol, and l-arabitol. Xylitol was the preferred substrate with K m =16.1 mM and k cat /K m =67.0 min -1 mM -1 , while l-arabitol was also a substrate for the enzyme with K m =31.1 mM and k cat /K m =6.5 min -1  mM -1 . Therefore, this enzyme from M. caribbica was named xylitol dehydrogenase (McXDH). McXDH had an optimum temperature and pH at 40°C and 9.5, respectively. The McXDH gene included a coding sequence of 1086 bp encoding a putative 362 amino acid protein of 39 kDa with an apparent homopentamer structure. Native McXDH and recombinant McXDH exhibited relative activities toward l-arabitol of approximately 20% that toward xylitol, suggesting the applicability of this enzyme with the functions of XDH and LAD to the development of pentose-fermenting Saccharomyces cerevisiae. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  7. Impaired succinic dehydrogenase activity of rat Purkinje cell mitochondria during aging.

    Science.gov (United States)

    Fattoretti, P; Bertoni-Freddari, C; Caselli, U; Paoloni, R; Meier-Ruge, W

    1998-03-16

    The perikaryal Purkinje cell mitochondria positive to the copper ferrocyanide histochemical reaction for succinic dehydrogenase (SDH) have been investigated by means of semiautomatic morphometric methods in rats of 3, 12 and 24 months of age. The number of organelles/microm3 of Purkinje cell cytoplasm (Numeric density: Nv), the average mitochondrial volume (V) and the mitochondrial volume fraction (Volume density: Vv) were the ultrastructural parameters taken into account. Nv was significantly higher at 12 than at 3 and 24 months of age. V was significantly decreased at 12 and 24 months of age, but no difference was envisaged between adult and old rats. Vv was significantly decreased in old animals vs. the other age groups. In young and old rats, the percentage of organelles larger than 0.32 microm3 was 13.5 and 11%, respectively, while these enlarged mitochondria accounted for less than 1% in the adult group. Since SDH activity is of critical importance when energy demand is high, the marked decrease of Vv supports an impaired capacity of the old Purkinje cells to match actual energy supply at sustained transmission of the nervous impulse. However, the high percentage of enlarged organelles found in old rats may witness a morphofunctional compensatory response.

  8. Studies on the Mechanism of Electron Bifurcation Catalyzed by Electron Transferring Flavoprotein (Etf) and Butyryl-CoA Dehydrogenase (Bcd) of Acidaminococcus fermentans*

    Science.gov (United States)

    Chowdhury, Nilanjan Pal; Mowafy, Amr M.; Demmer, Julius K.; Upadhyay, Vikrant; Koelzer, Sebastian; Jayamani, Elamparithi; Kahnt, Joerg; Hornung, Marco; Demmer, Ulrike; Ermler, Ulrich; Buckel, Wolfgang

    2014-01-01

    Electron bifurcation is a fundamental strategy of energy coupling originally discovered in the Q-cycle of many organisms. Recently a flavin-based electron bifurcation has been detected in anaerobes, first in clostridia and later in acetogens and methanogens. It enables anaerobic bacteria and archaea to reduce the low-potential [4Fe-4S] clusters of ferredoxin, which increases the efficiency of the substrate level and electron transport phosphorylations. Here we characterize the bifurcating electron transferring flavoprotein (EtfAf) and butyryl-CoA dehydrogenase (BcdAf) of Acidaminococcus fermentans, which couple the exergonic reduction of crotonyl-CoA to butyryl-CoA to the endergonic reduction of ferredoxin both with NADH. EtfAf contains one FAD (α-FAD) in subunit α and a second FAD (β-FAD) in subunit β. The distance between the two isoalloxazine rings is 18 Å. The EtfAf-NAD+ complex structure revealed β-FAD as acceptor of the hydride of NADH. The formed β-FADH− is considered as the bifurcating electron donor. As a result of a domain movement, α-FAD is able to approach β-FADH− by about 4 Å and to take up one electron yielding a stable anionic semiquinone, α-FAD⨪, which donates this electron further to Dh-FAD of BcdAf after a second domain movement. The remaining non-stabilized neutral semiquinone, β-FADH•, immediately reduces ferredoxin. Repetition of this process affords a second reduced ferredoxin and Dh-FADH− that converts crotonyl-CoA to butyryl-CoA. PMID:24379410

  9. Studies on the mechanism of electron bifurcation catalyzed by electron transferring flavoprotein (Etf) and butyryl-CoA dehydrogenase (Bcd) of Acidaminococcus fermentans.

    Science.gov (United States)

    Chowdhury, Nilanjan Pal; Mowafy, Amr M; Demmer, Julius K; Upadhyay, Vikrant; Koelzer, Sebastian; Jayamani, Elamparithi; Kahnt, Joerg; Hornung, Marco; Demmer, Ulrike; Ermler, Ulrich; Buckel, Wolfgang

    2014-02-21

    Electron bifurcation is a fundamental strategy of energy coupling originally discovered in the Q-cycle of many organisms. Recently a flavin-based electron bifurcation has been detected in anaerobes, first in clostridia and later in acetogens and methanogens. It enables anaerobic bacteria and archaea to reduce the low-potential [4Fe-4S] clusters of ferredoxin, which increases the efficiency of the substrate level and electron transport phosphorylations. Here we characterize the bifurcating electron transferring flavoprotein (EtfAf) and butyryl-CoA dehydrogenase (BcdAf) of Acidaminococcus fermentans, which couple the exergonic reduction of crotonyl-CoA to butyryl-CoA to the endergonic reduction of ferredoxin both with NADH. EtfAf contains one FAD (α-FAD) in subunit α and a second FAD (β-FAD) in subunit β. The distance between the two isoalloxazine rings is 18 Å. The EtfAf-NAD(+) complex structure revealed β-FAD as acceptor of the hydride of NADH. The formed β-FADH(-) is considered as the bifurcating electron donor. As a result of a domain movement, α-FAD is able to approach β-FADH(-) by about 4 Å and to take up one electron yielding a stable anionic semiquinone, α-FAD, which donates this electron further to Dh-FAD of BcdAf after a second domain movement. The remaining non-stabilized neutral semiquinone, β-FADH(•), immediately reduces ferredoxin. Repetition of this process affords a second reduced ferredoxin and Dh-FADH(-) that converts crotonyl-CoA to butyryl-CoA.

  10. The Activity of Escherichia coli Dihydroorotate Dehydrogenase Is Dependent on a Conserved Loop Identified by Sequence Homology, Mutagenesis, and Limited Proteolysis

    DEFF Research Database (Denmark)

    Björnberg, Olof; Grüner, Anne Charlotte; Roepstorff, Peter

    1999-01-01

    of dihydroorotate dehydrogenases, but sedimentation in sucrose gradients suggests a dimeric structure also of the E. coli enzyme. Product inhibition showed that the E. coli enzyme, in contrast to the L. lactis enzyme, has separate binding sites for dihydroorotate and the electron acceptor. Trypsin readily cleaved...... the E. coli enzyme into two fragments of 182 and 154 residues, respectively. Cleavage reduced the activity more than 100-fold but left other molecular properties, including the heat stability, intact. The trypsin cleavage site, at R182, is positioned in a conserved region that, in the L. lactis enzyme......, forms a loop where a cysteine residue is very critical for activity. In the corresponding position, the enzyme from E. coli has a serine residue. Mutagenesis of this residue (S175) to alanine or cysteine reduced the activities 10000- and 500-fold, respectively. The S175C mutant was also defective...

  11. Aldehyde dehydrogenase activity selects for the holoclone phenotype in prostate cancer cells

    International Nuclear Information System (INIS)

    Doherty, R.E.; Haywood-Small, S.L.; Sisley, K.; Cross, N.A.

    2011-01-01

    Highlights: ► Isolated ALDH Hi PC3 cells preferentially form primitive holoclone-type colonies. ► Primitive holoclone colonies are predominantly ALDH Lo but contain rare ALDH Hi cells. ► Holoclone-forming cells are not restricted to the ALDH Hi population. ► ALDH phenotypic plasticity occurs in PC3 cells (ALDH Lo to ALDH Hi and vice versa). ► ALDH Hi cells are observed but very rare in PC3 spheroids grown in stem cell medium. -- Abstract: Aldehyde dehydrogenase 1 (ALDH) activity is considered to be a marker of cancer stem cells (CSCs) in many tumour models, since these cells are more proliferative and tumourigenic than ALDH Lo cells in experimental models. However it is unclear whether all CSC-like cells are within the ALDH Hi population, or whether all ALDH Hi cells are highly proliferative and tumourigenic. The ability to establish a stem cell hierarchy in vitro, whereby sub-populations of cells have differing proliferative and differentiation capacities, is an alternate indication of the presence of stem cell-like populations within cell lines. In this study, we have examined the interaction between ALDH status and the ability to establish a stem cell hierarchy in PC3 prostate cancer cells. We demonstrate that PC3 cells contain a stem cell hierarchy, and isolation of ALDH Hi cells enriches for the most primitive holoclone population, however holoclone formation is not restricted to ALDH Hi cells. In addition, we show that ALDH activity undergoes phenotypic plasticity, since the ALDH Lo population can develop ALDH Hi populations comparable to parental cells within 2 weeks in culture. Furthermore, we show that the majority of ALDH Hi cells are found within the least primitive paraclone population, which is circumvented by culturing PC3 cells as spheroids in defined medium favouring stem cell characteristics. Although ALDH Hi status enriches for holoclone formation, this activity may be mediated by a minority of ALDH Hi cells.

  12. Effect of soil contamination with azadirachtin on dehydrogenase and catalase activity of soil

    Directory of Open Access Journals (Sweden)

    Rıdvan Kızılkaya

    2012-07-01

    Full Text Available nsecticides are used in modern agriculture in large quantities to control pests and increase crop yield. Their use, however, has resulted in the disruption of ecosystems because of the effects on non-target soil microorganisms, some environmental problems, and decreasing soil fertility. These negative effects of synthetic pesticides on the environment have led to the search for alternative means of pest control. One such alternative is use of natural plant products such as azadirachtin that have pesticidal activity. The aim of this experiment was to study the effect of soil contamination by azadirachtin (C35H44O16 on dehydrogenase (DHA and catalase activity (CA of soil under field conditions in Perm, Russia. The tests were conducted on loamy soil (pHH2O 6.7, ECH2O 0.213 dSm-1, organic carbon 0.99%, to which the following quantities of azadirachtin were added: 0, 15, 30 and 60 mL da-1 of soil. Experimental design was randomized plot design with three replications. The DHA and CA analyses were performed 7, 14 and 21 days after the field experiment was established. The results of field experiment showed that azadirachtin had a positive influence on the DHA and CA at different soil sampling times. The increased doses of azadirachtin applied resulted in the higher level of DHA and CA in soil. The soil DHA and CA showed the highest activity on the 21th day after 60 mL azadirachtin da-1 application doses.

  13. Enhanced pyruvate dehydrogenase activity improves cardiac outcomes in a murine model of cardiac arrest.

    Directory of Open Access Journals (Sweden)

    Lin Piao

    Full Text Available Post-ischemic changes in cellular metabolism alter myocardial and neurological function. Pyruvate dehydrogenase (PDH, the limiting step in mitochondrial glucose oxidation, is inhibited by increased expression of PDH kinase (PDK during ischemia/reperfusion injury. This results in decreased utilization of glucose to generate cellular ATP. Post-cardiac arrest (CA hypothermia improves outcomes and alters metabolism, but its influence on PDH and PDK activity following CA are unknown. We hypothesized that therapeutic hypothermia (TH following CA is associated with the inhibition of PDK activity and increased PDH activity. We further hypothesized that an inhibitor of PDK activity, dichloroacetate (DCA, would improve PDH activity and post-CA outcomes.Anesthetized and ventilated adult female C57BL/6 wild-type mice underwent a 12-minute KCl-induced CA followed by cardiopulmonary resuscitation. Compared to normothermic (37°C CA controls, administering TH (30°C improved overall survival (72-hour survival rate: 62.5% vs. 28.6%, P<0.001, post-resuscitation myocardial function (ejection fraction: 50.9±3.1% vs. 27.2±2.0%, P<0.001; aorta systolic pressure: 132.7±7.3 vs. 72.3±3.0 mmHg, P<0.001, and neurological scores at 72-hour post CA (9.5±1.3 vs. 5.4±1.3, P<0.05. In both heart and brain, CA increased lactate concentrations (1.9-fold and 3.1-fold increase, respectively, P<0.01, decreased PDH enzyme activity (24% and 50% reduction, respectively, P<0.01, and increased PDK protein expressions (1.2-fold and 1.9-fold, respectively, P<0.01. In contrast, post-CA treatment with TH normalized lactate concentrations (P<0.01 and P<0.05 and PDK expressions (P<0.001 and P<0.05, while increasing PDH activity (P<0.01 and P<0.01 in both the heart and brain. Additionally, treatment with DCA (0.2 mg/g body weight 30 min prior to CA improved both myocardial hemodynamics 2 hours post-CA (aortic systolic pressure: 123±3 vs. 96±4 mmHg, P<0.001 and 72-hour survival rates

  14. Role of a non-ionic surfactant in direct electron transfer-type bioelectrocatalysis by fructose dehydrogenase

    International Nuclear Information System (INIS)

    Kawai, Shota; Yakushi, Toshiharu; Matsushita, Kazunobu; Kitazumi, Yuki; Shirai, Osamu; Kano, Kenji

    2015-01-01

    Highlights: • Addition of Triton ® X-100 (1%) completely quenches the FDH-catalyzed current at hydrophobic electrode, but causes only small competitive effect at hydrophilic electrode. • Quartz crystal microbalance measurements support the adsorption of FDH and Triton ® X-100 on both of the electrodes. • The surfactant forms a monolayer on the hydrophobic electrode and FDH adsorbs on the surfactant monolayer. • The surfactant forms a bilayer on the hydrophilic electrode and FDH is embedded in the bilayer to communicate with the electrode. - ABSTRACT: A heterotrimeric membrane-bound fructose dehydrogenase (FDH) from Gluconobacter japonicus NBRC3260 contains FAD in subunit I and three heme C moieties in subunit II as the redox centers, and is one of the direct electron transfer (DET)-type redox enzymes. FDH-catalyzed current density of fructose oxidation at hydrophilic mercaptoethanol (MEtOH)-modified Au electrode is much larger than that at hydrophobic mercaptoethane (MEtn)-modified Au electrode. Addition of a non-ionic surfactant Triton ® X-100 (1%) completely quenches the catalytic current at the MEtn-modified Au electrode, while only small competitive effect is observed at the MEtOH-modified Au electrode. Quartz crystal microbalance measurements support the adsorption of FDH and Triton ® X-100 on both of the modified electrodes. We propose a model to explain the phenomenon as follows. The surfactant forms a monolayer on the hydrophobic MEtn-modified electrode with strong hydrophobic interaction, and FDH adsorbs on the surface of the surfactant monolayer. The monolayer inhibits the electron transfer from FDH to the electrode. On the other hand, the surfactant forms a bilayer on the hydrophilic MEtOH-modified electrode. The interaction between the surfactant bilayer and the hydrophilic electrode is relatively weak so that FDH replaces the surfactant and is embedded in the bilayer to communicate electrochemically with the hydrophilic electrode

  15. Compound heterozygous mutations in electron transfer flavoprotein dehydrogenase identified in a young Chinese woman with late-onset glutaric aciduria type II

    OpenAIRE

    Xue, Ying; Zhou, Yun; Zhang, Keqin; Li, Ling; Kayoumu, Abudurexiti; Chen, Liye; Wang, Yuhui; Lu, Zhiqiang

    2017-01-01

    Background Glutaric aciduria type II (GA II) is an autosomal recessive disorder affecting fatty acid and amino acid metabolism. The late-onset form of GA II disorder is almost exclusively associated with mutations in the electron transfer flavoprotein dehydrogenase (ETFDH) gene. Till now, the clinical features of late-onset GA II vary widely and pose a great challenge for diagnosis. The aim of the current study is to characterize the clinical phenotypes and genetic basis of a late-onset GAII ...

  16. Lactate dehydrogenase activity of rat epididymis and spermatozoa: Effect of constant light

    Directory of Open Access Journals (Sweden)

    RH Ponce

    2009-12-01

    Full Text Available During its passage through the epididymis, the gamete undergoes a process of “maturation” leading to the acquisition of its fertilizing ability. The epididymis displays regional variations in the morphology and metabolic properties of its epithelium which are relevant for the progressive development of mature sperm characteristics. The epididymis has spontaneous peristaltic contractions and receives sympathetic innervation that is modulated by melatonin, a hormone synthesized and released by the pineal gland. Constant lighting disrupts melatonin synthesis and secretion. We have studied the effect of constant light on lactate dehydrogenase (LDH; EC 1.1.1.27 and its isozyme C4 activities and protein content in whole epididymis, epididymal tissue and in spermatozoa from caput and cauda segments. Animals were exposed from birth to an illumination schedule of 14 h light: 10 h dark (group L:D. At 60 days of age one group of animals was submitted to constant light over 50 days (group L:L. In order to test the fertilizing ability, the rats of each group were mated with soliciting estrous females. The percentage of pregnancies in females mated with males maintained in L:L was remarkably lower than those in females mated with males maintained in the L:D photoperiod (44% and 88% respectively. Constant light increased protein concentration and LDH activity in caput as well as in cauda of total epididymis. On the contrary, in epididymal tissue, the protein content decreased in both epididymal sections compared with controls. When enzymatic activity was expressed in Units per spermatozoa, constant light induced a significant reduction of total LDH and LDHC4 in caput and cauda spermatozoa while LDH activity of epididymal tissue was not affected. In spite of the decrease in LDH per sperm cell when rats were exposed to constant light, in total epididymis (epididymis tissue plus sperm cells content and in spermatozoa, values of enzyme activities expressed per

  17. Active site of Zn2+-dependent sn-glycerol-1-phosphate dehydrogenase from Aeropyrum pernix K1

    Directory of Open Access Journals (Sweden)

    Jin-Suk Han

    2005-01-01

    Full Text Available The enzyme sn-glycerol-1-phosphate dehydrogenase (Gro1PDH, EC 1.1.1.261 is key to the formation of the enantiomeric configuration of the glycerophosphate backbone (sn-glycerol-1-phosphate of archaeal ether lipids. This enzyme catalyzes the reversible conversion between dihydroxyacetone phosphate and glycerol-1-phosphate. To date, no information about the active site and catalytic mechanism of this enzyme has been reported. Using the sequence and structural information for glycerol dehydrogenase, we constructed six mutants (D144N, D144A, D191N, H271A, H287A and D191N/H271A of Gro1PDH from Aeropyrum pernix K1 and examined their characteristics to clarify the active site of this enzyme. The enzyme was found to be a zinc-dependent metalloenzyme, containing one zinc ion for every monomer protein that was essential for activity. Site-directed mutagenesis of D144 increased the activity of the enzyme. Mutants D144N and D144A exhibited low affinity for the substrates and higher activity than the wild type, but their affinity for the zinc ion was the same as that of the wild type. Mutants D191N, H271A and H287A had a low affinity for the zinc ion and a low activity compared with the wild type. The double mutation, D191N/ H271A, had no enzyme activity and bound no zinc. From these results, it was clarified that residues D191, H271 and H287 participate in the catalytic activity of the enzyme by binding the zinc ion, and that D144 has an effect on substrate binding. The structure of the active site of Gro1PDH from A. pernix K1 seems to be similar to that of glycerol dehydrogenase, despite the differences in substrate specificity and biological role.

  18. Electrochemical Studies of the Inhibition and Activation Effects of Al (III on the Activity of Bovine Liver Glutamate Dehydrogenase

    Directory of Open Access Journals (Sweden)

    Shuping Bi

    2005-04-01

    Full Text Available Since the study of Al3+ ion on the enzyme activity by using of electrochemical techniques was rarely found in available literatures, the differential-pulse polarography (DPP technique was applied to study the effects of Al3+ ion on the glutamate dehydrogenase (GDH activity in the catalytical reaction of α-KG +NADH+NH4 + ⇔ L-Glu+NAD++H2O by monitoring the DPP reduction current of NAD+. At the plant and animal physiologically relevant pH values (pH=6.5 and 7.5, the GDH enzyme activities were strongly depended on the concentrations of the metal ion in the assay mixture solutions. In the lower Al (III concentration solutions (80μM, the inhibition effects of Al (III were shown again. The cyclic voltammetry of NAD+ and NAD+-GDH in the presence of Al (III can help to explain some biological phenomena. According to the differential-pulse polarography and cyclic voltammetry experiments, the present research confirmed that the electrochemical technique is a convenient and reliable sensor for accurate determination of enzyme activity in biological and environmental samples.

  19. High Aldehyde Dehydrogenase Activity Identifies a Subset of Human Mesenchymal Stromal Cells with Vascular Regenerative Potential.

    Science.gov (United States)

    Sherman, Stephen E; Kuljanin, Miljan; Cooper, Tyler T; Putman, David M; Lajoie, Gilles A; Hess, David A

    2017-06-01

    During culture expansion, multipotent mesenchymal stromal cells (MSCs) differentially express aldehyde dehydrogenase (ALDH), an intracellular detoxification enzyme that protects long-lived cells against oxidative stress. Thus, MSC selection based on ALDH-activity may be used to reduce heterogeneity and distinguish MSC subsets with improved regenerative potency. After expansion of human bone marrow-derived MSCs, cell progeny was purified based on low versus high ALDH-activity (ALDH hi ) by fluorescence-activated cell sorting, and each subset was compared for multipotent stromal and provascular regenerative functions. Both ALDH l ° and ALDH hi MSC subsets demonstrated similar expression of stromal cell (>95% CD73 + , CD90 + , CD105 + ) and pericyte (>95% CD146 + ) surface markers and showed multipotent differentiation into bone, cartilage, and adipose cells in vitro. Conditioned media (CDM) generated by ALDH hi MSCs demonstrated a potent proliferative and prosurvival effect on human microvascular endothelial cells (HMVECs) under serum-free conditions and augmented HMVEC tube-forming capacity in growth factor-reduced matrices. After subcutaneous transplantation within directed in vivo angiogenesis assay implants into immunodeficient mice, ALDH hi MSC or CDM produced by ALDH hi MSC significantly augmented murine vascular cell recruitment and perfused vessel infiltration compared with ALDH l ° MSC. Although both subsets demonstrated strikingly similar mRNA expression patterns, quantitative proteomic analyses performed on subset-specific CDM revealed the ALDH hi MSC subset uniquely secreted multiple proangiogenic cytokines (vascular endothelial growth factor beta, platelet derived growth factor alpha, and angiogenin) and actively produced multiple factors with chemoattractant (transforming growth factor-β, C-X-C motif chemokine ligand 1, 2, and 3 (GRO), C-C motif chemokine ligand 5 (RANTES), monocyte chemotactic protein 1 (MCP-1), interleukin [IL]-6, IL-8) and matrix

  20. Regulation of the activity of lactate dehydrogenases from four lactic acid bacteria

    NARCIS (Netherlands)

    Feldman-Salit, A.; Hering, S.; Messiha, H.L.; Veith, N.; Cojocaru, V.; Sieg, A.; Westerhoff, H.V.; Kreikemeyer, B.; Wade, R.C.; Fiedler, T.

    2013-01-01

    Despite high similarity in sequence and catalytic properties, the l-lactate dehydrogenases (LDHs) in lactic acid bacteria (LAB) display differences in their regulation that may arise from their adaptation to different habitats. We combined experimental and computational approaches to investigate the

  1. Correlation of viral RNA biosynthesis with glucose-6-phosphate dehydrogenase activity and host resistance

    Czech Academy of Sciences Publication Activity Database

    Šindelář, Luděk; Šindelářová, Milada

    2002-01-01

    Roč. 215, - (2002), s. 862-869 ISSN 0032-0935 R&D Projects: GA ČR GA522/99/1264 Institutional research plan: CEZ:AV0Z5038910 Keywords : Glucose 6 phosphate dehydrogenase * Nicotiana (viral infection) * Plant viruses Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.960, year: 2002

  2. Aldehyde dehydrogenase activity selects for the holoclone phenotype in prostate cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Doherty, R.E.; Haywood-Small, S.L. [Biomedical Research Centre, Sheffield Hallam University, Sheffield S1 1WB (United Kingdom); Sisley, K. [Department of Oncology, Academic Unit of Ophthalmology and Orthopties, University of Sheffield, Sheffield S10 2RX (United Kingdom); Cross, N.A., E-mail: n.cross@shu.ac.uk [Biomedical Research Centre, Sheffield Hallam University, Sheffield S1 1WB (United Kingdom)

    2011-11-04

    Highlights: Black-Right-Pointing-Pointer Isolated ALDH{sup Hi} PC3 cells preferentially form primitive holoclone-type colonies. Black-Right-Pointing-Pointer Primitive holoclone colonies are predominantly ALDH{sup Lo} but contain rare ALDH{sup Hi} cells. Black-Right-Pointing-Pointer Holoclone-forming cells are not restricted to the ALDH{sup Hi} population. Black-Right-Pointing-Pointer ALDH phenotypic plasticity occurs in PC3 cells (ALDH{sup Lo} to ALDH{sup Hi} and vice versa). Black-Right-Pointing-Pointer ALDH{sup Hi} cells are observed but very rare in PC3 spheroids grown in stem cell medium. -- Abstract: Aldehyde dehydrogenase 1 (ALDH) activity is considered to be a marker of cancer stem cells (CSCs) in many tumour models, since these cells are more proliferative and tumourigenic than ALDH{sup Lo} cells in experimental models. However it is unclear whether all CSC-like cells are within the ALDH{sup Hi} population, or whether all ALDH{sup Hi} cells are highly proliferative and tumourigenic. The ability to establish a stem cell hierarchy in vitro, whereby sub-populations of cells have differing proliferative and differentiation capacities, is an alternate indication of the presence of stem cell-like populations within cell lines. In this study, we have examined the interaction between ALDH status and the ability to establish a stem cell hierarchy in PC3 prostate cancer cells. We demonstrate that PC3 cells contain a stem cell hierarchy, and isolation of ALDH{sup Hi} cells enriches for the most primitive holoclone population, however holoclone formation is not restricted to ALDH{sup Hi} cells. In addition, we show that ALDH activity undergoes phenotypic plasticity, since the ALDH{sup Lo} population can develop ALDH{sup Hi} populations comparable to parental cells within 2 weeks in culture. Furthermore, we show that the majority of ALDH{sup Hi} cells are found within the least primitive paraclone population, which is circumvented by culturing PC3 cells as spheroids in

  3. Comparative analysis of succinate dehydrogenase activity in mammalian peripheral blood lymphocytes and radiomodifying action of gas hypoxis mixtures

    International Nuclear Information System (INIS)

    Gajdamakin, A.N.; Abramov, M.M.

    1987-01-01

    Radiprotective efficiency of gas hypoxic mixtures (GHM) containing 5-12% of oxygen and the rate of the reaction of succinate dehydrogenase (V SDG ) activity in peripheral blood lymphocytes upon breathing GHM were comparatively studied in rats and dogs. V SDG was 4393.5 (%O 2 ) -2,58 and 130.76 (%O 2 ) -1.42 in dogs and rats respectively. Taking into account that DMF in rats is a function of oxygen concentration in the mixture one can obtain a formula for determining a dose modifying factors (DMF) as a function of the rate of SDG activity reaction

  4. Common catabolic enzyme patterns in a microplankton community of the Humboldt Current System off northern and central-south Chile: Malate dehydrogenase activity as an index of water-column metabolism in an oxygen minimum zone

    Science.gov (United States)

    González, R. R.; Quiñones, R. A.

    2009-07-01

    An extensive subsurface oxygen minimum zone off northern and central-south Chile, associated with the Peru-Chile undercurrent, has important effects on the metabolism of the organisms inhabiting therein. Planktonic species deal with the hypoxic and anoxic environments by relying on biochemical as well as physiological processes related to their anaerobic metabolisms. Here we characterize, for the first time, the potential enzymatic activities involved in the aerobic and anaerobic energy production pathways of microplanktonic organisms (oxygen concentration and microplanktonic biomass in the oxygen minimum zone and adjacent areas of the Humboldt Current System water column. Our results demonstrate significant potential enzymatic activity of catabolic pathways in the oxygen minimum zone. Malate dehydrogenase had the highest oxidizing activity of nicotinamide adenine dinucleotide (reduced form) in the batch of catabolic enzymatic activities assayed, including potential pyruvate oxidoreductases activity, the electron transport system, and dissimilatory nitrate reductase. Malate dehydrogenase correlated significantly with almost all the enzymes analyzed within and above the oxygen minimum zone, and also with the oxygen concentration and microplankton biomass in the water column of the Humboldt Current System, especially in the oxygen minimum zone off Iquique. These results suggest a possible specific pattern for the catabolic activity of the microplanktonic realm associated with the oxygen minimum zone spread along the Humboldt Current System off Chile. We hypothesize that malate dehydrogenase activity could be an appropriate indicator of microplankton catabolism in the oxygen minimum zone and adjacent areas.

  5. Immunocapture and microplate-based activity and quantity measurement of pyruvate dehydrogenase in human peripheral blood mononuclear cells.

    Science.gov (United States)

    Liu, Xiaowen; Pervez, Hira; Andersen, Lars W; Uber, Amy; Montissol, Sophia; Patel, Parth; Donnino, Michael W

    2015-01-01

    Pyruvate dehydrogenase (PDH) activity is altered in many human disorders. Current methods require tissue samples and yield inconsistent results. We describe a modified method for measuring PDH activity from isolated human peripheral blood mononuclear cells (PBMCs). RESULTS/METHODOLOGY: We found that PDH activity and quantity can be successfully measured in human PBMCs. Freeze-thaw cycles cannot efficiently disrupt the mitochondrial membrane. Processing time of up to 20 h does not affect PDH activity with proteinase inhibitor addition and a detergent concentration of 3.3% showed maximum yield. Sample protein concentration is correlated to PDH activity and quantity in human PBMCs from healthy subjects. Measuring PDH activity from PBMCs is a novel, easy and less invasive way to further understand the role of PDH in human disease.

  6. Immunocapture and microplate-based activity and quantity measurement of pyruvate dehydrogenase in human peripheral blood mononuclear cells

    Science.gov (United States)

    Liu, Xiaowen; Pervez, Hira; Andersen, Lars W; Uber, Amy; Montissol, Sophia; Patel, Parth; Donnino, Michael W

    2015-01-01

    Background Pyruvate dehydrogenase (PDH) activity is altered in many human disorders. Current methods require tissue samples and yield inconsistent results. We describe a modified method for measuring PDH activity from isolated human peripheral blood mononuclear cells (PBMCs). Results/Methodology We found that PDH activity and quantity can be successfully measured in human PBMCs. Freeze-thaw cycles cannot efficiently disrupt the mitochondrial membrane. Processing time of up to 20 h does not affect PDH activity with proteinase inhibitor addition and a detergent concentration of 3.3% showed maximum yield. Sample protein concentration is correlated to PDH activity and quantity in human PBMCs from healthy subjects. Conclusion Measuring PDH activity from PBMCs is a novel, easy and less invasive way to further understand the role of PDH in human disease. PMID:25826140

  7. Level of coenzyme A and the activity of certain dehydrogenases under chronic low dose X-irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Cherkasova, L A; Novik, V A; Tsychun, G F [AN Belorusskoj SSR, Minsk. Inst. Fiziologii

    1975-01-01

    A study was made of the effect of long-term x ray irradiation (cumulative dose 50 R) on: the content of co-enzyme A (KoA) in the brain and liver, the activity of a number of oxydizing reducing enzymes in the brain mitochondria and heart muscle, and the blood glucocorticoid content. It was established that the metabolism of brain and liver KoA is quite stable, the enzymes of the brain tricarbonic acids and pyruvate-dehydrogenase cycle are labile.

  8. Incorporation of 14C glucose into glycogen and glucose-6-phosphate dehydrogenase activity in rat brain following carbon monoxide intoxication

    International Nuclear Information System (INIS)

    Sikorska, M.; Gorzkowski, B.; Szumanska, G.; Smialek, M.

    1975-01-01

    Incorporation of 14 C glucose into glycogen and glucose-6-phosphate dehydrogenase activity in rat brain following carbon monoxide intoxication was studied. In brains of rats tested on the 20, 30 and 60th minute of exposure to CO and immediately after removal from the chamber the enzyme activity showed no essential deviation from the control level. In the group of rats tested 1 hour after taking them out from the chamber increase of the enzyme activity was noticed, amounting to about 33% of the control value. The brains tested 24 hours after exposure showed the largest increase of the enzyme activity by about 94%. In the next time periods, 48 and 72 hours after intoxication, the enzyme activity was decreasing. The glycogen content in brains of control animals increased 3 hours after CO intoxication by about 69%. The increase of glycogen synthesis was expressed by increase of the total radioactivity, which amounted to 160% of the control value. (Z.M.)

  9. Autodisplay of active sorbitol dehydrogenase (SDH) yields a whole cell biocatalyst for the synthesis of rare sugars.

    Science.gov (United States)

    Jose, Joachim; von Schwichow, Steffen

    2004-04-02

    Whole cell biocatalysts are attractive technological tools for the regio- and enantioselective synthesis of products, especially from substrates with several identical reactive groups. In the present study, a whole cell biocatalyst for the synthesis of rare sugars from polyalcohols was constructed. For this purpose, sorbitol dehydrogenase (SDH) from Rhodobacter sphaeroides, a member of the short-chain dehydrogenase/reductase (SDR) family, was expressed on the surface of Escherichia coli using Autodisplay. Autodisplay is an efficient surface display system for Gram-negative bacteria and is based on the autotransporter secretion pathway. Transport of SDH to the outer membrane was monitored by SDS-PAGE and Western blotting of different cell fractions. The surface exposure of the enzyme could be verified by immunofluorescence microscopy and fluorescence activated cell sorting (FACS). The activity of whole cells displaying SDH at the surface was determined in an optical test. Specific activities were found to be 12 mU per 3.3 x 10(8) cells for the conversion of D-glucitol (sorbitol) to D-fructose, 7 mU for the conversion D-galactitol to D-tagatose, and 17 mU for the conversion of L-arabitol to L-ribulose. The whole cell biocatalyst obtained by surface display of SDH could also produce D-glucitol from D-fructose (29 mU per 3.3 x 10(8) cells).

  10. Effect of thoracic x-irradiation on glucose-6-phosphate dehydrogenase activity of the pectoral muscle of guinea pig

    International Nuclear Information System (INIS)

    Bhatavdekar, J.M.; Shah, V.C.

    1981-01-01

    The histochemical distribution of glucose-6-phosphate dehydrogenase (G6PD) was observed in the major pectoral muscle of a guinea pig that had received 240 R thoracic X-irradiation. The irradiation effects were studied at 24, 48 and 72 hrs after X-irradiation. Type I fibres of the pectoral muscle were deeply stained showing high activity whereas type II fibres demonstrated minimum enzyme activity. The intermediate fibres had medium levels of G6PD activity. Type II fibres showed more staining at 24 and 48 hrs as compared with control muscle. However, at 72 hrs all three fibre types showed a marked inhibition of G6PD activity. The significance of these changes suggests that muscle G6PD metabolism generally altered after irradiation, but the specific nature of these changes and their causes still remain unclear. (author)

  11. Mechanisms of activation of muscle branched-chain alpha-keto acid dehydrogenase during exercise in man

    DEFF Research Database (Denmark)

    Van Hall, Gerrit; MacLean, D A; Saltin, B

    1996-01-01

    1. Exercise leads to activation (dephosphorylation) of the branched-chain alpha-keto acid dehydrogenase (BCKADH). Here we investigate the effect of low pre-exercise muscle glycogen content and of branched-chain amino acid (BCAA) ingestion on the activity of BCKADH at rest and after 90 min of one......-leg knee-extensor exercise at 65% maximal one-leg power output in five subjects. 2. Pre-exercise BCAA ingestion (308 mg BCAAs (kg body wt)-1) caused an increased muscle BCAA uptake, a higher intramuscular BCAA concentration and activation of BCKADH both at rest (9 +/- 1 versus 25 +/- 5% for the control...... and BCAA test, respectively) and after exercise (27 +/- 4 versus 54 +/- 7%). 3. At rest the percentage active BCKADH was not different, 6 +/- 2% versus 5 +/- 1%, in the normal and low glycogen content leg (392 +/- 21 and 147 +/- 34 mumol glycosyl units (g dry muscle)-1, respectively). The post...

  12. Effect of low dose x irradiation on the succinate dehydrogenase activity of guinea pig, rat and mouse tissues

    Energy Technology Data Exchange (ETDEWEB)

    Shah, V C; Bhatavdekar, J M; Aravinda Babu, K [Gujarat Univ., Ahmedabad (India). Dept. of Zoology

    1976-07-01

    The histochemical changes in succinate dehydrogenase (SDH) were investigated in pectoralis major muscle of guinea pig, rat and mouse after level X-irradiation (72 R and 240 R) and compared with control animals. Biochemical studies were carried out on liver, kidney, muscle (pectoralis major), adrenal and spleen of these animals after low dose local X-irradiation and compared with control animals. Changes in SDH activity were studied up to 72-h post-irradiation, which shows that low dose local X-irradiation leads to increased enzymic activity. The increase in enzymic activity was remarkable in mouse tissues as compared with guinea pig and rat. Adrenals of all the three animals showed significant activation after all the doses of radiation studied. The significance of these results, with special reference to oxidative metabolism, has been discussed.

  13. NAD(P-DEPENDENT DEHYDROGENASE ACTIVITY IN PERIPHERAL BLOOD LYMPHOCYTES OF INFANTS WITH ENLARGEMENT OF PHARYNGEAL TONSILS

    Directory of Open Access Journals (Sweden)

    L. M. Kurtasova

    2014-01-01

    Full Text Available We have observed and examined 57 children 1 to 3 years old diagnosed with enlargement of pharyngeal tonsils. A control group was presented by 35 healthy children. Bioluminescence technique was applied for studying NAD(P-dependent dehydrogenase activity in peripheral blood lymphocytes. Activation of aerobic respiration and increasing activity of pentose phosphate cycle-dependent plastic processes were registered in blood lymphocytes of children with hypertrophic pharyngeal tonsils; along with decreased function of malate-aspartate shunt in energy metabolism of the cells, diminished anaerobic reaction of NADHdependent LDH, lower interaction between Krebs cycle and reactions of amino acid metabolism, and reduced activity of glutathione reductase.

  14. 5,5'-Dithiobis-(2-nitrobenzoic acid) as a probe for a non-essential cysteine residue at the medium chain acyl-coenzyme A dehydrogenase binding site of the human 'electron transferring flavoprotein' (ETF).

    Science.gov (United States)

    Parker, A; Engel, P C

    1999-01-01

    Human 'electron transferring flavoprotein' (ETF) was inactivated by the thiol-specific reagent 5,5'-dithiobis-(2-nitrobenzoic acid) (DTNB). The kinetic profile showed the reaction followed pseudo-first-order kinetics during the initial phase of inactivation. Monitoring the release of 5-thio-2-nitrobenzoate (TNB) showed that modification of 1 cysteine residue was responsible for the loss of activity. The inactivation of ETF by DTNB could be reversed upon incubation with thiol-containing reagents. The loss of activity was prevented by the inclusion of medium chain acyl-CoA dehydrogenase (MCAD) and octanoyl-CoA. Cyanolysis of the DTNB modified-ETF with KCN led to the release of TNB accompanied presumably by the formation of the thio-cyano enzyme and with almost full recovery of activity. Conservation studies and the lack of 100% inactivation, however, suggested that this cysteine residue is not essential for the interaction with MCAD.

  15. Diglycolic acid inhibits succinate dehydrogenase activity in human proximal tubule cells leading to mitochondrial dysfunction and cell death.

    Science.gov (United States)

    Landry, Greg M; Dunning, Cody L; Conrad, Taylor; Hitt, Mallory J; McMartin, Kenneth E

    2013-08-29

    Diethylene glycol (DEG) is a solvent used in consumer products allowing the increased risk for consumer exposure. DEG metabolism produces two primary metabolites, 2-hydroxyethoxyacetic acid (2-HEAA) and diglycolic acid (DGA). DGA has been shown to be the toxic metabolite responsible for the proximal tubule cell necrosis seen in DEG poisoning. The mechanism of DGA toxicity in the proximal tubule cell is not yet known. The chemical structure of DGA is very similar to citric acid cycle intermediates. Studies were designed to assess whether its mechanism of toxicity involves disruption of cellular metabolic pathways resulting in mitochondrial dysfunction. First, DGA preferentially inhibited succinate dehydrogenase, including human kidney cell enzyme, but had no effect on other citric acid cycle enzyme activities. DGA produces a cellular ATP depletion that precedes cell death. Human proximal tubule (HPT) cells, pre-treated with increasing DGA concentrations, showed significantly decreased oxygen consumption. DGA did not increase lactate levels, indicating no effect on glycolytic activity. DGA increased reactive oxygen species (ROS) production in HPT cells in a concentration and time dependent manner. These results indicate that DGA produced proximal tubule cell dysfunction by specific inhibition of succinate dehydrogenase and oxygen consumption. Disruption of these processes results in decreased energy production and proximal tubule cell death. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

  16. Reduced activity of 11beta-hydroxysteroid dehydrogenase type 2 is not responsible for sodium retention in nephrotic rats

    DEFF Research Database (Denmark)

    Bistrup, C; Thiesson, H C; Jensen, B L

    2005-01-01

    AIM: In mineralocorticoid target cells 11-beta-hydroxysteroid dehydrogenase type 2 (11betaHSD2) converts glucocorticoids into non-active metabolites thereby protecting the mineralocorticoid receptor (MR) from stimulation by glucocorticoids. In nephrotic syndrome, a decreased activity of 11betaHSD2...... has been suggested to allow glucocorticoids to stimulate MR, thereby contributing to sodium retention. We tested this hypothesis in the puromycin aminonucleoside model of nephrotic syndrome in rats. METHODS: Complete sodium and potassium intakes and excretions (faeces and urine) were measured in rats......)] to suppress endogenous glucocorticoids in the proteinuric stage during active sodium retention. RESULTS: Nephrotic rats developed proteinuria, positive sodium balance, decreased plasma aldosterone concentration, and decreased urinary Na(+)/K(+) ratio. 11betaHSD2 mRNA expression was down-regulated but protein...

  17. Adhesion activity of glyceraldehyde-3-phosphate dehydrogenase in a Chinese Streptococcus suis type 2 strain.

    Science.gov (United States)

    Wang, Kaicheng; Lu, Chengping

    2007-01-01

    A total of 36 streptococcal strains, including seven S. equi ssp.zooepidemicus, two S. suis type 1 (SS1), 24 SS2, two SS9, and one SS7, were tested for glyceraldehyde-3-phosphate dehydrogenase gene (gapdh). Except from non-virulent SS2 strain T1 5, all strains harboured gapdh. The gapdh of Chinese Sichuan SS2 isolate ZY05719 and Jiangsu SS2 isolate HA9801 were sequenced and then compared with published sequences in the GenBank. The comparison revealed a 99.9 % and 99.8 % similarity of ZY05719 and HA9801, respectively, with the published sequence. Adherence assay data demonstrated a significant ((p<0.05)) reduction in adhesion of SS2 in HEp-2 cells pre-incubated with purified GAPDH compared to non pre-incubated controls, suggesting the GAPDH mediates SS2 bacterial adhesion to host cells.

  18. Alcohol dehydrogenase gene ADH3 activates glucose alcoholic fermentation in genetically engineered Dekkera bruxellensis yeast

    DEFF Research Database (Denmark)

    Schifferdecker, Anna Judith; Siurkus, Juozas; Andersen, Mikael Rørdam

    2016-01-01

    Dekkera bruxellensis is a non-conventional Crabtree-positive yeast with a good ethanol production capability. Compared to Saccharomyces cerevisiae, its tolerance to acidic pH and its utilization of alternative carbon sources make it a promising organism for producing biofuel. In this study, we...... developed an auxotrophic transformation system and an expression vector, which enabled the manipulation of D. bruxellensis, thereby improving its fermentative performance. Its gene ADH3, coding for alcohol dehydrogenase, was cloned and overexpressed under the control of the strong and constitutive promoter...... TEF1. Our recombinant D. bruxellensis strain displayed 1.4 and 1.7 times faster specific glucose consumption rate during aerobic and anaerobic glucose fermentations, respectively; it yielded 1.2 times and 1.5 times more ethanol than did the parental strain under aerobic and anaerobic conditions...

  19. Inhibition of catalase by aminotriazole in vivo results in reduction of glucose-6-phosphate dehydrogenase activity in Saccharomyces cerevisiae cells.

    Science.gov (United States)

    Bayliak, M; Gospodaryov, D; Semchyshyn, H; Lushchak, V

    2008-04-01

    The inhibitor of catalase 3-amino-1,2,4-triazole (AMT) was used to study the physiological role of catalase in the yeast Saccharomyces cerevisiae under starvation. It was shown that AMT at the concentration of 10 mM did not affect the growth of the yeast. In vivo and in vitro the degree of catalase inhibition by AMT was concentration- and time-dependent. Peroxisomal catalase in bakers' yeast was more sensitive to AMT than the cytosolic one. In vivo inhibition of catalase by AMT in S. cerevisiae caused a simultaneous decrease in glucose-6-phosphate dehydrogenase activity and an increase in glutathione reductase activity. At the same time, the level of protein carbonyls, a marker of oxidative modification, was not affected. Possible mechanisms compensating the negative effects caused by AMT inhibition of catalase are discussed.

  20. STUDIES ON THE DYNAMICS OF DEHYDROGENASES KREBS CYCLE ACTIVITY AT MONILINIA LAXA (ADERH. & RUHL. HONEY FUNGUS GROWN ON MEDIA WITH DIFFERENT CARBOHYDRATES

    Directory of Open Access Journals (Sweden)

    Elena Ciornea

    2010-09-01

    Full Text Available As ubiquitous organisms, fungi grow on a large number of organic substrate, alive or dead, confronting therefore with a wide variety of carbohydrates and various physical factors, and their versatility to adapt and be able to use a large number of these compounds could provide them the chance to survive. Given that, these fungi have a rich enzyme equipment that allows them to operate on different metabolic pathways, this study aims to monitor the dynamics activity of some Krebs cycle dehydrogenases in Monilinia laxa (Aderh & Ruhl. Honey species parasitic on various species of plum trees. To this end, the fungus was cultivated in vitro on media enriched with different carbohydrates and the isocitrate dehydrogenase, �-cetoglutarate dehydrogenase, succinate dehydrogenase and malate dehydrogenase activity in the fungus mycelium was followed, at 7, respectively, 14 days after the inoculation of the culture medium and determined using the spectrophotometric Sîsoev and Krasna method (Cojocaru, D.C., 2009. Data revealed obvious differences depending on the type of carbohydrate introduced into the medium and the age of the culture mycelia.

  1. STUDIES ON THE DYNAMICS OF DEHYDROGENASES KREBS CYCLE ACTIVITY AT MONILINIA LAXA (ADERH. & RUHL. HONEY FUNGUS GROWN ON MEDIA WITH DIFFERENT CARBOHYDRATES

    Directory of Open Access Journals (Sweden)

    Elena Ciornea

    2011-11-01

    Full Text Available As ubiquitous organisms, fungi grow on a large number of organic substrate, alive or dead, confronting therefore with a wide variety of carbohydrates and various physical factors, and their versatility to adapt and be able to use a large number of these compounds could provide them the chance to survive. Given that, these fungi have a rich enzyme equipment that allows them to operate on different metabolic pathways, this study aims to monitor the dynamics activity of some Krebs cycle dehydrogenases in Monilinia laxa (Aderh & Ruhl. Honey species parasitic on various species of plum trees. To this end, the fungus was cultivated in vitro on media enriched with different carbohydrates and the isocitrate dehydrogenase, �-cetoglutarate dehydrogenase, succinate dehydrogenase and malate dehydrogenase activity in the fungus mycelium was followed, at 7, respectively, 14 days after the inoculation of the culture medium and determined using the spectrophotometric Sîsoev and Krasna method (Cojocaru, D.C., 2009. Data revealed obvious differences depending on the type of carbohydrate introduced into the medium and the age of the culture mycelia.

  2. Structure of Dihydroorotate Dehydrogenase B: Electron Transfer between Two Flavin Groups Bridged by an Iron-Sulphur Cluster

    DEFF Research Database (Denmark)

    Rowland, Poul; Nørager, Sofie; Jensen, Kaj Frank

    2000-01-01

    BACKGROUND: The fourth step and only redox reaction in pyrimidine de novo biosynthesis is catalyzed by the flavoprotein dihydroorotate dehydrogenase (DHOD). Based on their sequences, DHODs are grouped into two major families. Lactococcus lactis is one of the few organisms with two DHODs, A and B....... RESULTS: Crystal structures have been determined for DHODB and its product complex. The DHODB heterotetramer is composed of two closely interacting PyrDB-PyrK dimers with the [2Fe-2S] cluster in their interface centered between the FMN and FAD groups. Conformational changes are observed between...

  3. Cellobiose dehydrogenase of Chaetomium sp. INBI 2-26(-): structural basis of enhanced activity toward glucose at neutral pH.

    Science.gov (United States)

    Vasilchenko, Liliya G; Karapetyan, Karen N; Yershevich, Olga P; Ludwig, Roland; Zamocky, Marcel; Peterbauer, Clemens K; Haltrich, Dietmar; Rabinovich, Mikhail L

    2011-05-01

    Cellobiose dehydrogenase (CDH) is an extracellular fungal flavocytochrome specifically oxidizing cellooligosaccharides and lactose to corresponding (-lactones by a variety of electron acceptors. In contrast to basidiomycetous CDHs, CDHs of ascomycetes also display certain activity toward glucose. The objective of this study was to establish the structural reasons of such an activity of CDH from mesophilic ascomycete Chaetomium sp. INBI 2-26 (ChCDH). The complete amino acid sequence of ChCDH displayed high levels of similarity with the amino acid sequences of CDHs from the thermophilic fungi Thielavia heterotallica and Myriococcum thermophilum. Peptide mass fingerprinting of purified ChCDH provided evidence for the oxidation of methionine residues in the FAD-domain. Comparative homology modeling of the structure of the ChCDH FAD-domain in complex with the transition state analog based on the structure of the same complex of basidiomycetous CDH (1NAA) as template indicated possible structural reasons for the enhanced activity of ascomycetous CDHs toward glucose at neutral pH, which is a prerequisite for application of CDH in a variety of biocompatible biosensors and biofuel cells. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Determination of glutamate dehydrogenase activity and its kinetics in mouse tissues using metabolic mapping (quantitative enzyme histochemistry).

    Science.gov (United States)

    Botman, Dennis; Tigchelaar, Wikky; Van Noorden, Cornelis J F

    2014-11-01

    Glutamate dehydrogenase (GDH) catalyses the reversible conversion of glutamate into α-ketoglutarate with the concomitant reduction of NAD(P)(+) to NAD(P)H or vice versa. GDH activity is subject to complex allosteric regulation including substrate inhibition. To determine GDH kinetics in situ, we assessed the effects of various glutamate concentrations in combination with either the coenzyme NAD(+) or NADP(+) on GDH activity in mouse liver cryostat sections using metabolic mapping. NAD(+)-dependent GDH V(max) was 2.5-fold higher than NADP(+)-dependent V(max), whereas the K(m) was similar, 1.92 mM versus 1.66 mM, when NAD(+) or NADP(+) was used, respectively. With either coenzyme, V(max) was determined at 10 mM glutamate and substrate inhibition was observed at higher glutamate concentrations with a K(i) of 12.2 and 3.95 for NAD(+) and NADP(+) used as coenzyme, respectively. NAD(+)- and NADP(+)-dependent GDH activities were examined in various mouse tissues. GDH activity was highest in liver and much lower in other tissues. In all tissues, the highest activity was found when NAD(+) was used as a coenzyme. In conclusion, GDH activity in mice is highest in the liver with NAD(+) as a coenzyme and highest GDH activity was determined at a glutamate concentration of 10 mM. © The Author(s) 2014.

  5. Effects of clofibric acid on the activity and activity state of the hepatic branched-chain 2-oxo acid dehydrogenase complex.

    OpenAIRE

    Zhao, Y; Jaskiewicz, J; Harris, R A

    1992-01-01

    Feeding clofibric acid to rats caused little or no change in total activity of the liver branched-chain 2-oxo acid dehydrogenase complex (BCODC). No change in mass of liver BCODC was detected by immunoblot analysis in response to dietary clofibric acid. No changes in abundance of mRNAs for the BCODC E1 alpha, E1 beta and E2 subunits were detected by Northern-blot analysis. Likewise, dietary clofibric acid had no effect on the activity state of liver BCODC (percentage of enzyme in the dephosph...

  6. Multiple roles of mobile active center loops in the E1 component of the Escherichia coli pyruvate dehydrogenase complex - Linkage of protein dynamics to catalysis

    Science.gov (United States)

    Jordan, Frank; Arjunan, Palaniappa; Kale, Sachin; Nemeria, Natalia S.; Furey, William

    2009-01-01

    The region encompassing residues 401–413 on the E1 component of the pyruvate dehydrogenase multienzyme complex from Escherichia coli comprises a loop (the inner loop) which was not seen in the X-ray structure in the presence of thiamin diphosphate, the required cofactor for the enzyme. This loop is seen in the presence of a stable analogue of the pre-decarboxylation intermediate, the covalent adduct between the substrate analogue methyl acetylphosphonate and thiamin diphosphate, C2α-phosphonolactylthiamin diphosphate. It has been shown that the residue H407 and several other residues on this loop are required to reduce the mobility of the loop so electron density corresponding to it can be seen once the pre-decarboxylation intermediate is formed. Concomitantly, the loop encompassing residues 541–557 (the outer loop) appears to work in tandem with the inner loop and there is a hydrogen bond between the two loops ensuring their correlated motion. The inner loop was shown to: a) sequester the active center from carboligase side reactions; b) assist the interaction between the E1 and the E2 components, thereby affecting the overall reaction rate of the entire multienzyme complex; c) control substrate access to the active center. Using viscosity effects on kinetics it was shown that formation of the pre-decarboxylation intermediate is specifically affected by loop movement. A cysteine-less variant was created for the E1 component, onto which cysteines were substituted at selected loop positions. Introducing an electron spin resonance spin label and an 19F NMR label onto these engineered cysteines, the loop mobility was examined: a) both methods suggested that in the absence of ligand, the loop exists in two conformations; b) line-shape analysis of the NMR signal at different temperatures, enabled estimation of the rate constant for loop movement, and this rate constant was found to be of the same order of magnitude as the turnover number for the enzyme under the

  7. A pyrroloquinolinequinone-dependent glucose dehydrogenase (PQQ-GDH)-electrode with direct electron transfer based on polyaniline modified carbon nanotubes for biofuel cell application

    International Nuclear Information System (INIS)

    Schubart, Ivo W.; Göbel, Gero; Lisdat, Fred

    2012-01-01

    Graphical abstract: - Abstract: In this study we present a pyrroloquinolinequinone-dependent glucose dehydrogenase [(PQQ)-GDH] electrode with direct electron transfer between the enzyme and electrode. Soluble pyrroloquinolinequinone-dependent glucose dehydrogenase from Acinetobacter calcoaceticus is covalently bound to an electropolymerized polyaniline copolymer film on a multi-walled carbon nanotube (MWCNT)-modified gold electrode. The pulsed electropolymerization of 2-methoxyaniline-5-sulfonic acid (MASA) and m-aminobenzoic acid (ABA) is optimized with respect to the efficiency of the bioelectrocatalytic conversion of glucose. The glucose oxidation starts at −0.1 V vs. Ag/AgCl and current densities up to 500 μA/cm 2 at low potential of +0.1 V vs. Ag/AgCl can be achieved. The electrode shows a glucose sensitivity in the range from 0.1 mM to 5 mM at a potential of +0.1 V vs. Ag/Ag/Cl. The dynamic range is extended to 100 mM at +0.4 V vs. Ag/AgCl. The electron transfer mechanism is studied and buffer effects are investigated. The developed enzyme electrode is examined for bioenergetic application by assembling of a membrane-less biofuel cell. For the cathode a bilirubin oxidase (BOD) based MWCNT-modified gold electrode with direct electron transfer (DET) is used. The biofuel cell exhibits a cell potential of 680 ± 20 mV and a maximum power density of up to 65 μW/cm 2 at 350 mV vs. Ag/AgCl.

  8. In Silico Identification and in Vitro Activity of Novel Natural Inhibitors of Trypanosoma brucei Glyceraldehyde-3-phosphate-dehydrogenase

    Directory of Open Access Journals (Sweden)

    Fabian C. Herrmann

    2015-09-01

    Full Text Available As part of our ongoing efforts to identify natural products with activity against pathogens causing neglected tropical diseases, we are currently performing an extensive screening of natural product (NP databases against a multitude of protozoan parasite proteins. Within this project, we screened a database of NPs from a commercial supplier, AnalytiCon Discovery (Potsdam, Germany, against Trypanosoma brucei glyceraldehyde-3-phosphate dehydrogenase (TbGAPDH, a glycolytic enzyme whose inhibition deprives the parasite of energy supply. NPs acting as potential inhibitors of the mentioned enzyme were identified using a pharmacophore-based virtual screening and subsequent docking of the identified hits into the active site of interest. In a set of 700 structures chosen for the screening, 13 (1.9% were predicted to possess significant affinity towards the enzyme and were therefore tested in an in vitro enzyme assay using recombinant TbGAPDH. Nine of these in silico hits (69% showed significant inhibitory activity at 50 µM, of which two geranylated benzophenone derivatives proved to be particularly active with IC50 values below 10 µM. These compounds also showed moderate in vitro activity against T. brucei rhodesiense and may thus represent interesting starting points for further optimization.

  9. In Silico Identification and in Vitro Activity of Novel Natural Inhibitors of Trypanosoma brucei Glyceraldehyde-3-phosphate-dehydrogenase.

    Science.gov (United States)

    Herrmann, Fabian C; Lenz, Mairin; Jose, Joachim; Kaiser, Marcel; Brun, Reto; Schmidt, Thomas J

    2015-09-03

    As part of our ongoing efforts to identify natural products with activity against pathogens causing neglected tropical diseases, we are currently performing an extensive screening of natural product (NP) databases against a multitude of protozoan parasite proteins. Within this project, we screened a database of NPs from a commercial supplier, AnalytiCon Discovery (Potsdam, Germany), against Trypanosoma brucei glyceraldehyde-3-phosphate dehydrogenase (TbGAPDH), a glycolytic enzyme whose inhibition deprives the parasite of energy supply. NPs acting as potential inhibitors of the mentioned enzyme were identified using a pharmacophore-based virtual screening and subsequent docking of the identified hits into the active site of interest. In a set of 700 structures chosen for the screening, 13 (1.9%) were predicted to possess significant affinity towards the enzyme and were therefore tested in an in vitro enzyme assay using recombinant TbGAPDH. Nine of these in silico hits (69%) showed significant inhibitory activity at 50 µM, of which two geranylated benzophenone derivatives proved to be particularly active with IC50 values below 10 µM. These compounds also showed moderate in vitro activity against T. brucei rhodesiense and may thus represent interesting starting points for further optimization.

  10. Aldehyde dehydrogenase (ALDH activity does not select for cells with enhanced aggressive properties in malignant melanoma.

    Directory of Open Access Journals (Sweden)

    Lina Prasmickaite

    Full Text Available BACKGROUND: Malignant melanoma is an exceptionally aggressive, drug-resistant and heterogeneous cancer. Recently it has been shown that melanoma cells with high clonogenic and tumourigenic abilities are common, but markers distinguishing such cells from cells lacking these abilities have not been identified. There is therefore no definite evidence that an exclusive cell subpopulation, i.e. cancer stem cells (CSC, exists in malignant melanoma. Rather, it is suggested that multiple cell populations are implicated in initiation and progression of the disease, making it of importance to identify subpopulations with elevated aggressive properties. METHODS AND FINDINGS: In several other cancer forms, Aldehyde Dehydrogenase (ALDH, which plays a role in stem cell biology and resistance, is a valuable functional marker for identification of cells that show enhanced aggressiveness and drug-resistance. Furthermore, the presence of ALDH(+ cells is linked to poor clinical prognosis in these cancers. By analyzing cell cultures, xenografts and patient biopsies, we showed that aggressive melanoma harboured a large, distinguishable ALDH(+ subpopulation. In vivo, ALDH(+ cells gave rise to ALDH(- cells, while the opposite conversion was rare, indicating a higher abilities of ALDH(+ cells to reestablish tumour heterogeneity with respect to the ALDH phenotype. However, both ALDH(+ and ALDH(- cells demonstrated similarly high abilities for clone formation in vitro and tumour initiation in vivo. Furthermore, both subpopulations showed similar sensitivity to the anti-melanoma drugs, dacarbazine and lexatumumab. CONCLUSIONS: These findings suggest that ALDH does not distinguish tumour-initiating and/or therapy-resistant cells, implying that the ALDH phenotype is not associated with more-aggressive subpopulations in malignant melanoma, and arguing against ALDH as a "universal" marker. Besides, it was shown that the ability to reestablish tumour heterogeneity is not

  11. Active learners in sustainable electronics and it

    DEFF Research Database (Denmark)

    Schultz, Ole

    This poster-presentation is about active learning in a course sustainable wireless electronics and it. Active learning understood as practical lab-exercises and a team chosen project.......This poster-presentation is about active learning in a course sustainable wireless electronics and it. Active learning understood as practical lab-exercises and a team chosen project....

  12. 21 CFR 862.1670 - Sorbitol dehydrogenase test system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Sorbitol dehydrogenase test system. 862.1670... Systems § 862.1670 Sorbitol dehydrogenase test system. (a) Identification. A sorbitol dehydrogenase test system is a device intended to measure the activity of the enzyme sorbitol dehydrogenase in serum...

  13. Genetic analysis of central carbon metabolism unveils an amino acid substitution that alters maize NAD-dependent isocitrate dehydrogenase activity.

    Directory of Open Access Journals (Sweden)

    Nengyi Zhang

    2010-04-01

    Full Text Available Central carbon metabolism (CCM is a fundamental component of life. The participating genes and enzymes are thought to be structurally and functionally conserved across and within species. Association mapping utilizes a rich history of mutation and recombination to achieve high resolution mapping. Therefore, applying association mapping in maize (Zea mays ssp. mays, the most diverse model crop species, to study the genetics of CCM is a particularly attractive system.We used a maize diversity panel to test the CCM functional conservation. We found heritable variation in enzyme activity for every enzyme tested. One of these enzymes was the NAD-dependent isocitrate dehydrogenase (IDH, E.C. 1.1.1.41, in which we identified a novel amino-acid substitution in a phylogenetically conserved site. Using candidate gene association mapping, we identified that this non-synonymous polymorphism was associated with IDH activity variation. The proposed mechanism for the IDH activity variation includes additional components regulating protein level. With the comparison of sequences from maize and teosinte (Zea mays ssp. Parviglumis, the maize wild ancestor, we found that some CCM genes had also been targeted for selection during maize domestication.Our results demonstrate the efficacy of association mapping for dissecting natural variation in primary metabolic pathways. The considerable genetic diversity observed in maize CCM genes underlies heritable phenotypic variation in enzyme activities and can be useful to identify putative functional sites.

  14. Electron-transfer studies with a new flavin adenine dinucleotide dependent glucose dehydrogenase and osmium polymers of different redox potentials.

    Science.gov (United States)

    Zafar, Muhammad Nadeem; Wang, Xiaoju; Sygmund, Christoph; Ludwig, Roland; Leech, Dónal; Gorton, Lo

    2012-01-03

    A new extracellular flavin adenine dinucleotide (FAD)-dependent glucose dehydrogenase from Glomerella cingulata (GcGDH) was electrochemically studied as a recognition element in glucose biosensors. The redox enzyme was recombinantly produced in Pichia pastoris and homogeneously purified, and its glucose-oxidizing properties on spectrographic graphite electrodes were investigated. Six different Os polymers, the redox potentials of which ranged in a broad potential window between +15 and +489 mV versus the normal hydrogen electrode (NHE), were used to immobilize and "wire" GcGDH to the spectrographic graphite electrode's surface. The GcGDH/Os polymer modified electrodes were evaluated by chronoamperometry using flow injection analysis. The current response was investigated using a stepwisely increased applied potential. It was observed that the ratio of GcGDH/Os polymer and the overall loading of the enzyme electrode significantly affect the performance of the enzyme electrode for glucose oxidation. The best-suited Os polymer [Os(4,4'-dimethyl-2,2'-bipyridine)(2)(PVI)Cl](+) had a potential of +309 mV versus NHE, and the optimum GcGDH/Os polymer ratio was 1:2 yielding a maximum current density of 493 μA·cm(-2) at a 30 mM glucose concentration. © 2011 American Chemical Society

  15. Glutamine-Elicited Secretion of Glucagon-Like Peptide 1 Is Governed by an Activated Glutamate Dehydrogenase.

    Science.gov (United States)

    Andersson, Lotta E; Shcherbina, Liliya; Al-Majdoub, Mahmoud; Vishnu, Neelanjan; Arroyo, Claudia Balderas; Aste Carrara, Jonathan; Wollheim, Claes B; Fex, Malin; Mulder, Hindrik; Wierup, Nils; Spégel, Peter

    2018-03-01

    Glucagon-like peptide 1 (GLP-1), secreted from intestinal L cells, glucose dependently stimulates insulin secretion from β-cells. This glucose dependence prevents hypoglycemia, rendering GLP-1 analogs a useful and safe treatment modality in type 2 diabetes. Although the amino acid glutamine is a potent elicitor of GLP-1 secretion, the responsible mechanism remains unclear. We investigated how GLP-1 secretion is metabolically coupled in L cells (GLUTag) and in vivo in mice using the insulin-secreting cell line INS-1 832/13 as reference. A membrane-permeable glutamate analog (dimethylglutamate [DMG]), acting downstream of electrogenic transporters, elicited similar alterations in metabolism as glutamine in both cell lines. Both DMG and glutamine alone elicited GLP-1 secretion in GLUTag cells and in vivo, whereas activation of glutamate dehydrogenase (GDH) was required to stimulate insulin secretion from INS-1 832/13 cells. Pharmacological inhibition in vivo of GDH blocked secretion of GLP-1 in response to DMG. In conclusion, our results suggest that nonelectrogenic nutrient uptake and metabolism play an important role in L cell stimulus-secretion coupling. Metabolism of glutamine and related analogs by GDH in the L cell may explain why GLP-1 secretion, but not that of insulin, is activated by these secretagogues in vivo. © 2017 by the American Diabetes Association.

  16. The effects of chemical and radioactive properties of Tl-201 on human erythrocyte glucose 6-phosphate dehydrogenase activity

    International Nuclear Information System (INIS)

    Sahin, Ali; Senturk, Murat; Ciftci, Mehmet; Varoglu, Erhan; Kufrevioglu, Omer Irfan

    2010-01-01

    Aim: The inhibitory effects of thallium-201 ( 201 Tl) solution on human erythrocyte glucose 6-phosphate dehydrogenase (G6PD) activity were investigated. Methods: For this purpose, erythrocyte G6PD was initially purified 835-fold at a yield of 41.7% using 2',5'-Adenosine diphosphate sepharose 4B affinity gel chromatography. The purification was monitored by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, which showed a single band for the final enzyme preparation. The in vitro and in vivo effects of the 201 Tl solution including Tl + , Fe +3 and Cu +2 metals and the in vitro effects of the radiation effect of the 201 Tl solution and non-radioactive Tl + , Fe +3 and Cu +2 metals on human erythrocyte G6PD enzyme were studied. Enzyme activity was determined with the Beutler method at 340 nm using a spectrophotometer. All purification procedures were carried out at +4 deg. C. Results: 201 Tl solution and radiation exposure had inhibitory effects on the enzyme activity. IC 50 value of 201 Tl solution was 36.86 μl ([Tl + ]: 0.0036 μM, [Cu +2 ]: 0.0116 μM, [Fe +3 ]: 0.0132 μM), of human erythrocytes G6PD. Seven human patients were also used for in vivo studies of 201 Tl solution. Furthermore, non-radioactive Tl + , Fe +3 and Cu +2 were found not to have influenced the enzyme in vitro. Conclusion: Human erythrocyte G6PD activity was inhibited by exposure for up to 10 minutes to 0.057 mCi/kg 201 Tl solution. It was detected in in vitro and in vivo studies that the human erythrocyte G6PD enzyme is inhibited due to the radiation effect of 201 Tl solution.

  17. Synthesis, conformational analysis, and biological activity of new analogues of thiazole-4-carboxamide adenine dinucleotide (TAD) as IMP dehydrogenase inhibitors.

    Science.gov (United States)

    Franchetti, Palmarisa; Cappellacci, Loredana; Pasqualini, Michela; Petrelli, Riccardo; Jayaprakasan, Vetrichelvan; Jayaram, Hiremagalur N; Boyd, Donald B; Jain, Manojkumar D; Grifantini, Mario

    2005-03-15

    Thiazole-4-carboxamide adenine dinucleotide (TAD) analogues T-2'-MeAD (1) and T-3'-MeAD (2) containing, respectively, a methyl group at the ribose 2'-C-, and 3'-C-position of the adenosine moiety, were prepared as potential selective human inosine monophosphate dehydrogenase (IMPDH) type II inhibitors. The synthesis of heterodinucleotides was carried out by CDI-catalyzed coupling reaction of unprotected 2'-C-methyl- or 3'-C-methyl-adenosine 5'-monophosphate with 2',3'-O-isopropylidene-tiazofurin 5'-monophosphate, and then deisopropylidenation. Biological evaluation of dinucleotides 1 and 2 as inhibitors of recombinant human IMPDH type I and type II resulted in a good activity. Inhibition of both isoenzymes by T-2'-MeAD and T-3'-MeAD was noncompetitive with respect to NAD substrate. Binding of T-3'-MeAD was comparable to that of parent compound TAD, while T-2'-MeAD proved to be a weaker inhibitor. However, no significant difference was found in inhibition of the IMPDH isoenzymes. T-2'-MeAD and T-3'-MeAD were found to inhibit the growth of K562 cells (IC(50) 30.7 and 65.0muM, respectively).

  18. The Spatial Variability of Soil Dehydrogenase Activity: A Survey in Urban Soils

    OpenAIRE

    Kizilkaya, Ridvan; Aşkin, Tayfun

    2007-01-01

    Information on soil microorganisms and their activity used to determine microbiological characteristics are very important for soil quality and productivity. Studies of enzyme activities provide information on the biochemical processes occurring in soil. There is growing evidence that soil biological parameters may be potential and sensitive indicators of soil ecological conditions and soil management. Soil microbiological parameters may be evaluated statistically due to application of geosta...

  19. Nocturnal activity of 11β-hydroxy steroid dehydrogenase type 1 is increased in type 1 diabetic children.

    Science.gov (United States)

    Barat, P; Brossaud, J; Lacoste, A; Vautier, V; Nacka, F; Moisan, M-P; Corcuff, J-B

    2013-04-01

    The objective of this study was to investigate low-grade inflammation in children with type 1 diabetes (T1D) and its association with cortisol levels as well as its bioavailability through 11β-hydroxy steroid dehydrogenase type 1 (11β-HSD1) activity. Children with T1D (n=45) and their non-diabetic siblings (n=28) participated in the study. Interleukin-6 (IL-6) and high-sensitivity C-reactive protein (CRPhs) were measured between 1400 and 1800h. Glucocorticoid metabolites were measured in the first morning urine on clinic day and 11β-HSD1 activity was estimated by tetrahydrocortisol/tetrahydrocortisone (THF/THE) ratio. Diabetic patients presented with an increased THF/THE ratio compared with controls (median: 0.68 [range: 0.45-1.18] vs 0.45 [0.27-0.98], respectively; Pvs 0.6 [0.6-2.2], respectively; P=0.43) and CRPhs (0.4mg/L [0-7.4] vs 0.3 [0-8.2]; P=0.26, respectively). When adjusted for age, gender and BMI, the THF/THE ratio was significantly associated with CRPhs (β=0.32, P=0.02) in diabetic patients, but not in controls. Low-grade inflammation assessed by plasma CRPhs and IL-6 concentrations was not detectable in our cohort of T1D children. Nocturnal 11β-HSD1 activity was increased and associated with plasma CRPhs concentration in diabetic patients. These results may be explained by either a direct or inflammation-mediated effect of the relative hepatic lack of insulin due to subcutaneous insulin therapy. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  20. Myricetin is a novel inhibitor of human inosine 5′-monophosphate dehydrogenase with anti-leukemia activity

    International Nuclear Information System (INIS)

    Pan, Huiling; Hu, Qian; Wang, Jingyuan; Liu, Zehui; Wu, Dang; Lu, Weiqiang; Huang, Jin

    2016-01-01

    Human inosine 5′-monophosphate dehydrogenase (hIMPDH) is a rate-limiting enzyme in the de novo biosynthetic pathway of purine nucleotides, playing crucial roles in cellular proliferation, differentiation, and transformation. Dysregulation of hIMPDH expression and activity have been found in a variety of human cancers including leukemia. In this study, we found that myricetin, a naturally occurring phytochemical existed in berries, wine and tea, was a novel inhibitor of human type 1 and type 2 IMPDH (hIMPDH1/2) with IC_5_0 values of 6.98 ± 0.22 μM and 4.10 ± 0.14 μM, respectively. Enzyme kinetic analysis using Lineweaver-Burk plot revealed that myricetin is a mix-type inhibitor for hIMPDH1/2. Differential scanning fluorimetry and molecular docking simulation data demonstrate that myricetin is capable of binding with hIMPDH1/2. Myricetin treatment exerts potent anti-proliferative and pro-apoptotic effects on K562 human leukemia cells in a dose-dependent manner. Importantly, cytotoxicity of myricetin on K562 cells were markedly attenuated by exogenous addition of guanosine, a salvage pathway of maintaining intracellular pool of guanine nucleotides. Taking together, these results indicate that natural product myricetin exhibits potent anti-leukemia activity by interfering with purine nucleotides biosynthetic pathway through the suppression of hIMPDH1/2 catalytic activity. - Highlights: • Myricetin, a common dietary flavonoid, is a novel inhibitor of hIMPDH1/2. • Myricetin directly binds with hIMPDH1/2 and induces cell cycle arrest and apoptosis of leukemia cells. • The cytotoxicity of myricetin on K562 cells is markedly attenuated by exogenous addition of guanosine.

  1. Hypoxia-induced glucose-6-phosphate dehydrogenase overexpression and -activation in pulmonary artery smooth muscle cells: implication in pulmonary hypertension

    Science.gov (United States)

    Chettimada, Sukrutha; Gupte, Rakhee; Rawat, Dhwajbahadur; Gebb, Sarah A.; McMurtry, Ivan F.

    2014-01-01

    Severe pulmonary hypertension is a debilitating disease with an alarmingly low 5-yr life expectancy. Hypoxia, one of the causes of pulmonary hypertension, elicits constriction and remodeling of the pulmonary arteries. We now know that pulmonary arterial remodeling is a consequence of hyperplasia and hypertrophy of pulmonary artery smooth muscle (PASM), endothelial, myofibroblast, and stem cells. However, our knowledge about the mechanisms that cause these cells to proliferate and hypertrophy in response to hypoxic stimuli is still incomplete, and, hence, the treatment for severe pulmonary arterial hypertension is inadequate. Here we demonstrate that the activity and expression of glucose-6-phosphate dehydrogenase (G6PD), the rate-limiting enzyme of the pentose phosphate pathway, are increased in hypoxic PASM cells and in lungs of chronic hypoxic rats. G6PD overexpression and -activation is stimulated by H2O2. Increased G6PD activity contributes to PASM cell proliferation by increasing Sp1 and hypoxia-inducible factor 1α (HIF-1α), which directs the cells to synthesize less contractile (myocardin and SM22α) and more proliferative (cyclin A and phospho-histone H3) proteins. G6PD inhibition with dehydroepiandrosterone increased myocardin expression in remodeled pulmonary arteries of moderate and severe pulmonary hypertensive rats. These observations suggest that altered glucose metabolism and G6PD overactivation play a key role in switching the PASM cells from the contractile to synthetic phenotype by increasing Sp1 and HIF-1α, which suppresses myocardin, a key cofactor that maintains smooth muscle cell in contractile state, and increasing hypoxia-induced PASM cell growth, and hence contribute to pulmonary arterial remodeling and pathogenesis of pulmonary hypertension. PMID:25480333

  2. Myricetin is a novel inhibitor of human inosine 5′-monophosphate dehydrogenase with anti-leukemia activity

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Huiling; Hu, Qian; Wang, Jingyuan; Liu, Zehui; Wu, Dang [Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237 (China); Lu, Weiqiang, E-mail: wqlu@bio.ecnu.edu.cn [Shanghai Key Laboratory of Regulatory Biology, Institute of Biomedical Sciences and School of Life Sciences, East China Normal University, 500 Dongchuan Road, Shanghai 200241 (China); Huang, Jin, E-mail: huangjin@ecust.edu.cn [Shanghai Key Laboratory of New Drug Design, School of Pharmacy, East China University of Science and Technology, 130 Mei Long Road, Shanghai 200237 (China)

    2016-09-02

    Human inosine 5′-monophosphate dehydrogenase (hIMPDH) is a rate-limiting enzyme in the de novo biosynthetic pathway of purine nucleotides, playing crucial roles in cellular proliferation, differentiation, and transformation. Dysregulation of hIMPDH expression and activity have been found in a variety of human cancers including leukemia. In this study, we found that myricetin, a naturally occurring phytochemical existed in berries, wine and tea, was a novel inhibitor of human type 1 and type 2 IMPDH (hIMPDH1/2) with IC{sub 50} values of 6.98 ± 0.22 μM and 4.10 ± 0.14 μM, respectively. Enzyme kinetic analysis using Lineweaver-Burk plot revealed that myricetin is a mix-type inhibitor for hIMPDH1/2. Differential scanning fluorimetry and molecular docking simulation data demonstrate that myricetin is capable of binding with hIMPDH1/2. Myricetin treatment exerts potent anti-proliferative and pro-apoptotic effects on K562 human leukemia cells in a dose-dependent manner. Importantly, cytotoxicity of myricetin on K562 cells were markedly attenuated by exogenous addition of guanosine, a salvage pathway of maintaining intracellular pool of guanine nucleotides. Taking together, these results indicate that natural product myricetin exhibits potent anti-leukemia activity by interfering with purine nucleotides biosynthetic pathway through the suppression of hIMPDH1/2 catalytic activity. - Highlights: • Myricetin, a common dietary flavonoid, is a novel inhibitor of hIMPDH1/2. • Myricetin directly binds with hIMPDH1/2 and induces cell cycle arrest and apoptosis of leukemia cells. • The cytotoxicity of myricetin on K562 cells is markedly attenuated by exogenous addition of guanosine.

  3. In vitro effects of metals and pesticides on dehydrogenase activity in ...

    African Journals Online (AJOL)

    AJB SERVER

    2007-01-04

    Jan 4, 2007 ... Lin CH, Lerch RN, Kremer RJ, Garrett HC, Udawatta RP, George MF. (2005). Soil microbiological activities in vegetative buffer strips and their association with herbicide degradation. AFTA 2005 Conference. Proceedings pp 1 – 10. Mårtensson AM (1992). Effects of agrochemicals and heavy metals on.

  4. Effects of biogenic aldehydes and aldehyde dehydrogenase inhibitors on rat brain tryptophan hydroxylase activity in vitro.

    Science.gov (United States)

    Nilsson, G E; Tottmar, O

    1987-04-21

    The effect of indole-3-acetaldehyde, 5-hydroxyindole-3-acetaldehyde, disulfiram, diethyldithiocarbamate, coprine, and 1-amino-cyclopropanol on tryptophan hydroxylase activity was studied in vitro using high performance liquid chromatography with electro-chemical detection. With the analytical method developed, 5-hydroxytryptophan, serotonin, and 5-hydroxyindole-3-acetic acid could be measured simultaneously. Indole-3-acetaldehyde (12-1200 microM) was found to cause a 6-33% inhibition of the enzyme. Dependent upon the nature of the sulfhydryl- or reducing-agent (dithiotreitol, glutathione, or ascorbate) present in the incubates, the degree of inhibition by disulfiram varied, probably due to the formation of various mixed disulfides. Also the presence of diethyldithiocarbamate (160-1600 microM) was found to inhibit tryptophan hydroxylase (28-91%), while 5-hydroxyindole-3-acetaldehyde, coprine, or 1-aminocyclopropanol appeared to have no effect on the enzyme activity.

  5. Succinate dehydrogenase assembly factor 2 is needed for assembly and activity of mitochondrial complex II and for normal root elongation in Arabidopsis.

    Science.gov (United States)

    Huang, Shaobai; Taylor, Nicolas L; Ströher, Elke; Fenske, Ricarda; Millar, A Harvey

    2013-02-01

    Mitochondria complex II (succinate dehydrogenase, SDH) plays a central role in respiratory metabolism as a component of both the electron transport chain and the tricarboxylic acid cycle. We report the identification of an SDH assembly factor by analysis of T-DNA insertions in At5g51040, a protein with unknown function that was identified by mass spectrometry analysis as a low abundance mitochondrial protein. This gene is co-expressed with a number of genes encoding mitochondrial proteins, including SDH1-1, and has low partial sequence similarity to human SDHAF2, a protein required for flavin-adenine dinucleotide (FAD) insertion into SDH. In contrast to observations of other SDH deficient lines in Arabidopsis, the sdhaf2 line did not affect photosynthetic rate or stomatal conductance, but instead showed inhibition of primary root elongation with early lateral root emergence, presumably due to the low SDH activity caused by the reduced abundance of SDHAF2. Both roots and leaves showed succinate accumulation but different responses in the abundance of other organic acids and amino acids assayed. Isolated mitochondria showed lowered SDH1 protein abundance, lowered maximal SDH activity and less protein-bound flavin-adenine dinucleotide (FAD) at the molecular mass of SDH1 in the gel separation. The short root phenotype and SDH function of sdhaf2 was fully complemented by transformation with SDHAF2. Application of the SDH inhibitor, malonate, phenocopied the sdhaf2 root architecture in WT. Whole root respiratory assays showed no difference between WT and sdhaf2, but micro-respirometry of the tips of roots clearly showed low oxygen consumption in sdhaf2 which could explain a metabolic deficit responsible for root tip growth. © 2012 The Authors The Plant Journal © 2012 Blackwell Publishing Ltd.

  6. Dehydrogenase activity and quality of leachates in Technosols with gossan and sulfide materials from the São Domingos mine

    Science.gov (United States)

    Santos, Erika; Abreu, Manuela; Macías, Felipe; de Varennes, Amarílis

    2014-05-01

    Wastes produced by mining activity in São Domingos (Portuguese Iberian Pyrite Belt) were disposed over a large area. To speed up the ecological rehabilitation in this mine, an integrative strategy using different amendments+mine wastes was used to produce Technosols with enhanced soil functions. To evaluate the efficiency of these Technosols the dehydrogenase activity and chemical quality of leachates were monitored. Technosols were composed of different mine wastes (gossan and sulfide materials), collected at the São Domingos mine, and mixtures of amendments applied at 30 and 75 Mg/ha (rockwool+agriculture wastes+wastes from liquors distillation of strawberry tree fruits (Arbutus unedo L.) and/or carobs (Ceratonia siliqua L. fruits)). Three assays, under controlled conditions, were carried out: (1 and 2) Sulfide or gossan materials with/without amendments; (3) Sulfide wastes, with/without amendments, incubated during four months and then with application of an overlayer of gossan (~3 cm thick) with/without the same amendments. Dehydrogenase activity (DHA) and chemical characteristics of leachates (multielemental concentration, pH, and electric conductivity) were determined after four/seven/thirteen months of incubation. Sulfide wastes had more hazardous characteristics (pH~2 and total concentrations (g/kg) of Al (58.1), As (1.1), Cu (2.1), Fe (107.3), Pb (11.7), S (65.3) and Zn (1.1) than the gossan materials (pH=4.3; g/kg, Al: 24.8, As: 3.0, Cu: 0.2, Fe: 129, Pb: 9.2, S: 13.7, Zn: 0.04). Amendments application to gossan (assay 2) enhanced DHA in both sampling periods (µg TPF g dry weight 16 h-1, Control: 0,72-1,78; Amended treatments: 2.49-16.36 depending on mixture/application rate/sampling period). Greater application rates stimulated DHA (more than 1.5-fold with 75 Mg/ha). No differences were observed in DHA in the gossan layer with/without amendments (assay 3) suggesting a negative impact on gossan microrganisms from sulfide materials located below. In

  7. Effects of high-fat diet and physical activity on pyruvate dehydrogenase kinase-4 in mouse skeletal muscle

    Directory of Open Access Journals (Sweden)

    Rinnankoski-Tuikka Rita

    2012-06-01

    Full Text Available Abstract Background The expression of PDK4 is elevated by diabetes, fasting and other conditions associated with the switch from the utilization of glucose to fatty acids as an energy source. It is previously shown that peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α, a master regulator of energy metabolism, coactivates in cell lines pyruvate dehydrogenase kinase-4 (PDK4 gene expression via the estrogen-related receptor α (ERRα. We investigated the effects of long-term high-fat diet and physical activity on the expression of PDK4, PGC-1α and ERRα and the amount and function of mitochondria in skeletal muscle. Methods Insulin resistance was induced by a high-fat (HF diet for 19 weeks in C57BL/6 J mice, which were either sedentary or with access to running wheels. The skeletal muscle expression levels of PDK4, PGC-1α and ERRα were measured and the quality and quantity of mitochondrial function was assessed. Results The HF mice were more insulin-resistant than the low-fat (LF -fed mice. Upregulation of PDK4 and ERRα mRNA and protein levels were seen after the HF diet, and when combined with running even more profound effects on the mRNA expression levels were observed. Chronic HF feeding and voluntary running did not have significant effects on PGC-1α mRNA or protein levels. No remarkable difference was found in the amount or function of mitochondria. Conclusions Our results support the view that insulin resistance is not mediated by the decreased qualitative or quantitative properties of mitochondria. Instead, the role of PDK4 should be contemplated as a possible contributor to high-fat diet-induced insulin resistance.

  8. Inhibition of telomerase activity preferentially targets aldehyde dehydrogenase-positive cancer stem-like cells in lung cancer

    Directory of Open Access Journals (Sweden)

    Iniesta Pilar

    2011-08-01

    Full Text Available Abstract Background Mortality rates for advanced lung cancer have not declined for decades, even with the implementation of novel chemotherapeutic regimens or the use of tyrosine kinase inhibitors. Cancer Stem Cells (CSCs are thought to be responsible for resistance to chemo/radiotherapy. Therefore, targeting CSCs with novel compounds may be an effective approach to reduce lung tumor growth and metastasis. We have isolated and characterized CSCs from non-small cell lung cancer (NSCLC cell lines and measured their telomerase activity, telomere length, and sensitivity to the novel telomerase inhibitor MST312. Results The aldehyde dehydrogenase (ALDH positive lung cancer cell fraction is enriched in markers of stemness and endowed with stem cell properties. ALDH+ CSCs display longer telomeres than the non-CSC population. Interestingly, MST312 has a strong antiproliferative effect on lung CSCs and induces p21, p27 and apoptosis in the whole tumor population. MST312 acts through activation of the ATM/pH2AX DNA damage pathway (short-term effect and through decrease in telomere length (long-term effect. Administration of this telomerase inhibitor (40 mg/kg in the H460 xenograft model results in significant tumor shrinkage (70% reduction, compared to controls. Combination therapy consisting of irradiation (10Gy plus administration of MST312 did not improve the therapeutic efficacy of the telomerase inhibitor alone. Treatment with MST312 reduces significantly the number of ALDH+ CSCs and their telomeric length in vivo. Conclusions We conclude that antitelomeric therapy using MST312 mainly targets lung CSCs and may represent a novel approach for effective treatment of lung cancer.

  9. Molecular Basis for Converting (2S-Methylsuccinyl-CoA Dehydrogenase into an Oxidase

    Directory of Open Access Journals (Sweden)

    Simon Burgener

    2017-12-01

    Full Text Available Although flavoenzymes have been studied in detail, the molecular basis of their dioxygen reactivity is only partially understood. The members of the flavin adenosine dinucleotide (FAD-dependent acyl-CoA dehydrogenase and acyl-CoA oxidase families catalyze similar reactions and share common structural features. However, both enzyme families feature opposing reaction specificities in respect to dioxygen. Dehydrogenases react with electron transfer flavoproteins as terminal electron acceptors and do not show a considerable reactivity with dioxygen, whereas dioxygen serves as a bona fide substrate for oxidases. We recently engineered (2S-methylsuccinyl-CoA dehydrogenase towards oxidase activity by rational mutagenesis. Here we characterized the (2S-methylsuccinyl-CoA dehydrogenase wild-type, as well as the engineered (2S-methylsuccinyl-CoA oxidase, in detail. Using stopped-flow UV-spectroscopy and liquid chromatography-mass spectrometry (LC-MS based assays, we explain the molecular base for dioxygen reactivity in the engineered oxidase and show that the increased oxidase function of the engineered enzyme comes at a decreased dehydrogenase activity. Our findings add to the common notion that an increased activity for a specific substrate is achieved at the expense of reaction promiscuity and provide guidelines for rational engineering efforts of acyl-CoA dehydrogenases and oxidases.

  10. Enhanced enzymatic activity of glycerol-3-phosphate dehydrogenase from the cryophilic Saccharomyces kudriavzevii.

    Science.gov (United States)

    Oliveira, Bruno M; Barrio, Eladio; Querol, Amparo; Pérez-Torrado, Roberto

    2014-01-01

    During the evolution of the different species classified within the Saccharomyces genus, each one has adapted to live in different environments. One of the most important parameters that have influenced the evolution of Saccharomyces species is the temperature. Here we have focused on the study of the ability of certain species as Saccharomyces kudriavzevii to grow at low temperatures, in contrast to Saccharomyces cerevisiae. We observed that S. kudriavzevii strains isolated from several regions are able to synthesize higher amounts of glycerol, a molecule that has been shown to accumulate in response to freeze and cold stress. To explain this observation at the molecular level we studied the expression of glycerol biosynthetic pathway genes and we observed a higher expression of GPD1 gene in S. kudriavzevii compared to S. cerevisiae in micro-vinification conditions. We observed higher enzymatic activity of Gpd1p in S. kudriavzevii in response to osmotic and cold stress. Also, we determined that S. kudriavzevii Gpd1p enzyme presents increased catalytic properties that will contribute to increase glycerol production. Finally, we evaluated the glycerol production with S. cerevisiae, S. kudriavzevii or a recombinant Gpd1p variant in the same background and observed that the S. kudriavzevii enzyme produced increased glycerol levels at 12 or 28°C. This suggests that glycerol is increased in S. kudriavzevii mainly due to increased V max of the Gpd1p enzyme. All these differences indicate that S. kudriavzevii has changed the metabolism to promote the branch of the glycolytic pathway involved in glycerol production to adapt to low temperature environments and maintain the NAD(+)/NADH ratio in alcoholic fermentations. This knowledge is industrially relevant due to the potential use, for example, of S. cerevisiae-S. kudriavzevii hybrids in the wine industry where glycerol content is an important quality parameter.

  11. Elevated lactate dehydrogenase activity and increased cardiovascular mortality in the arsenic-endemic areas of southwestern Taiwan

    Energy Technology Data Exchange (ETDEWEB)

    Liao, Ya-Tang [Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Taiwan (China); Graduate Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taiwan (China); Genomics Research Center, Academia Sinica, Taiwan (China); Chen, Chien-Jen [Graduate Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taiwan (China); Genomics Research Center, Academia Sinica, Taiwan (China); Li, Wan-Fen [Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Taiwan (China); Hsu, Ling-I [Genomics Research Center, Academia Sinica, Taiwan (China); Tsai, Li-Yu; Huang, Yeou-Lih [Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Taiwan (China); Sun, Chien-Wen [Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Taiwan (China); Chen, Wei J., E-mail: wjchen@ntu.edu.tw [Graduate Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taiwan (China); Genetic Epidemiology Core Laboratory, National Taiwan University Center for Genomic Medicine, Taiwan (China); Wang, Shu-Li, E-mail: slwang@nhri.org.tw [Division of Environmental Health and Occupational Medicine, National Health Research Institutes, Taiwan (China); Department of Public Health, College of Public Health, China Medical University, Taichung, Taiwan (China)

    2012-08-01

    Arsenic ingestion has been linked to increasing global prevalence of and mortality from cardiovascular disease (CVD); arsenic can be removed from drinking water to reduce related health effects. Lactate dehydrogenase (LDH) is used for the evaluation of acute arsenic toxicity in vivo and in vitro, but it is not validated for the evaluation of long-term, chronic arsenic exposure. The present study examined the long-term effect of chronic arsenic exposure on CVD and serum LDH levels, after consideration of arsenic metabolism capacity. A total of 380 subjects from an arseniasis-endemic area and 303 from a non-endemic area of southwestern Taiwan were recruited in 2002. Various urinary arsenic species were analyzed using high-performance liquid chromatography (HPLC) and hydride generation systems. Fasting serum was used for quantitative determination of the total LDH activity. A significant dose–response relationship was observed between arsenic exposure and LDH elevation, independent of urinary arsenic profiles (P < 0.001). Furthermore, abnormal LDH elevation was associated with CVD mortality after adjustment for Framingham risk scores for 10-year CVD and arsenic exposure (hazard ratio, 3.98; 95% confidence interval, 1.07–14.81). LDH was elevated in subjects with arsenic exposure in a dose-dependent manner. LDH is a marker of arsenic toxicity associated with CVD mortality. Results of this study have important implications for use in ascertaining long-term arsenic exposure risk of CVD. -- Highlights: ► We showed that arsenic exposure was correlated with LDH elevation. ► LDH elevation was related to arsenic methylation capacity. ► Abnormal LDH elevation can be a marker of susceptibility to CVD mortality.

  12. Effect of Follicular Fluid and Platelet-Activating Factor on Lactate Dehydrogenase C Expression in Human Asthenozoospermic Samples

    Directory of Open Access Journals (Sweden)

    Tahereh Esmaeilpour

    2014-01-01

    Full Text Available Background: Application of follicular fluid (FF and platelet-activating factor (PAF in artificial insemination improves sperm motility. Lactate dehydrogenase C (LDH-C is a key enzyme for sperm motility. In this study, the effects of FF and PAF on the sperm motility index and LDH-C expression were investigated. Moreover, LDH-C expression was compared between asthenozoospermic and normozoospermic samples. Methods: The expression of LDH-C was examined by quantitative real-time polymerase chain reaction (q-RT PCR and western blotting after it was treated with optimized concentrations of FF and PAF in twenty asthenozoospermic samples. Also, LDH-C expression was evaluated in five normozoospermic samples. Results: Samples with 75% FF and 100 nM of PAF had an increase in their percentages of progressive and slowly motile sperms and a decrease in their percentages of non-progressive and non-motile sperms. Moreover, LDH-C mRNA transcripts were not changed following PAF and FF treatment, and LDH-C protein was detected in highly progressive motile specimens treated with FF in the asthenozoospermic samples. Furthermore, LDH-C expression was more detectable in the normal sperms. Conclusion: Our results indicated that PAF had more beneficial effects than FF on sperm motility in the asthenozoospermic samples (P=0.0001, although the LDH-C expressions of the sperms were not changed significantly in both groups. We found no association between LDH-C expression and sperm motility after FF and PAF actions. This finding, however, requires further investigation. The fact that LDH-C protein was detected in the normozoospermic, but not asthenozoospermic, samples could be cited as a reason for the infertility in these patients.

  13. Elevated lactate dehydrogenase activity and increased cardiovascular mortality in the arsenic-endemic areas of southwestern Taiwan

    International Nuclear Information System (INIS)

    Liao, Ya-Tang; Chen, Chien-Jen; Li, Wan-Fen; Hsu, Ling-I; Tsai, Li-Yu; Huang, Yeou-Lih; Sun, Chien-Wen; Chen, Wei J.; Wang, Shu-Li

    2012-01-01

    Arsenic ingestion has been linked to increasing global prevalence of and mortality from cardiovascular disease (CVD); arsenic can be removed from drinking water to reduce related health effects. Lactate dehydrogenase (LDH) is used for the evaluation of acute arsenic toxicity in vivo and in vitro, but it is not validated for the evaluation of long-term, chronic arsenic exposure. The present study examined the long-term effect of chronic arsenic exposure on CVD and serum LDH levels, after consideration of arsenic metabolism capacity. A total of 380 subjects from an arseniasis-endemic area and 303 from a non-endemic area of southwestern Taiwan were recruited in 2002. Various urinary arsenic species were analyzed using high-performance liquid chromatography (HPLC) and hydride generation systems. Fasting serum was used for quantitative determination of the total LDH activity. A significant dose–response relationship was observed between arsenic exposure and LDH elevation, independent of urinary arsenic profiles (P < 0.001). Furthermore, abnormal LDH elevation was associated with CVD mortality after adjustment for Framingham risk scores for 10-year CVD and arsenic exposure (hazard ratio, 3.98; 95% confidence interval, 1.07–14.81). LDH was elevated in subjects with arsenic exposure in a dose-dependent manner. LDH is a marker of arsenic toxicity associated with CVD mortality. Results of this study have important implications for use in ascertaining long-term arsenic exposure risk of CVD. -- Highlights: ► We showed that arsenic exposure was correlated with LDH elevation. ► LDH elevation was related to arsenic methylation capacity. ► Abnormal LDH elevation can be a marker of susceptibility to CVD mortality.

  14. Atividade da 6-fosfogliconato desidrogenase em deficientes de glicose-6-fosfato desidrogenase Activity of 6-phosphogluconate dehydrogenase in glucose-6-phosphate dehydrogenase deficiency

    Directory of Open Access Journals (Sweden)

    Daniela B. Nicolielo

    2006-06-01

    to know better the actuation of these enzymes. The goal of this study was to evaluate the 6PGD enzymatic activity on a population with G6PD deficiency, to verify if there is an elevation of the activity of this enzyme, and try to correlate to a possible increase on the number of reticulocytes or the presence of alterations on red series. The research with 2657 male individuals detected 97 deficient for G6PD, which determined a 3.65% prevalence for the Bauru (SP region, with mean enzymatic activity of 1.74 UI.g Hb-1. min-1 at 37ºC, 14,4% of the normal G6PD activity. Mean 6PGD enzymatic activity was 9.5 UI.g Hb-1. min-1 at 37ºC, and was elevated in 47.4% of the G6PD deficient individuals. The result obtained did not confirm the hypothesis that the elevation of the 6PGD enzymatic activity, in G6PD deficient individuals, was due to the presence of an increase of reticulocytes in blood stream, age or erythrocytometric alterations that could denote anemia. The most plausible theory is that the auto-limited hemolysis, imposed by oxidative processes, preserves young erythrocytes that have an elevated enzymatic activity, as naturally these enzymes lose activity with cellular aging.

  15. Effects of clofibric acid on the activity and activity state of the hepatic branched-chain 2-oxo acid dehydrogenase complex.

    Science.gov (United States)

    Zhao, Y; Jaskiewicz, J; Harris, R A

    1992-01-01

    Feeding clofibric acid to rats caused little or no change in total activity of the liver branched-chain 2-oxo acid dehydrogenase complex (BCODC). No change in mass of liver BCODC was detected by immunoblot analysis in response to dietary clofibric acid. No changes in abundance of mRNAs for the BCODC E1 alpha, E1 beta and E2 subunits were detected by Northern-blot analysis. Likewise, dietary clofibric acid had no effect on the activity state of liver BCODC (percentage of enzyme in the dephosphorylated, active, form) of rats fed on a chow diet. However, dietary clofibric acid greatly increased the activity state of liver BCODC of rats fed on a diet deficient in protein. No stable change in liver BCODC kinase activity was found in response to clofibric acid in either chow-fed or low-protein-fed rats. Clofibric acid had a biphasic effect on flux through BCODC in hepatocytes prepared from low-protein-fed rats. Stimulation of BCODC flux at low concentrations was due to clofibric acid inhibition of BCODC kinase, which in turn allowed activation of BCODC by BCODC phosphatase. Inhibition of BCODC flux at high concentrations was due to direct inhibition of BCODC by clofibric acid. The results suggest that the effects of clofibric acid in vivo on branched-chain amino acid metabolism can be explained by the inhibitory effects of this drug on BCODC kinase. Images Fig. 2. Fig. 3. PMID:1637295

  16. Reversible inactivation of CO dehydrogenase with thiol compounds

    Energy Technology Data Exchange (ETDEWEB)

    Kreß, Oliver [Department of Microbiology, University of Bayreuth, 95440 Bayreuth (Germany); Gnida, Manuel [Department of Chemistry, University of Paderborn, 33098 Paderborn (Germany); Pelzmann, Astrid M. [Department of Microbiology, University of Bayreuth, 95440 Bayreuth (Germany); Marx, Christian [Institute of Biochemistry and Biophysics, Friedrich-Schiller-University of Jena, 07745 Jena (Germany); Meyer-Klaucke, Wolfram [Department of Chemistry, University of Paderborn, 33098 Paderborn (Germany); Meyer, Ortwin, E-mail: Ortwin.Meyer@uni-bayreuth.de [Department of Microbiology, University of Bayreuth, 95440 Bayreuth (Germany)

    2014-05-09

    Highlights: • Rather large thiols (e.g. coenzyme A) can reach the active site of CO dehydrogenase. • CO- and H{sub 2}-oxidizing activity of CO dehydrogenase is inhibited by thiols. • Inhibition by thiols was reversed by CO or upon lowering the thiol concentration. • Thiols coordinate the Cu ion in the [CuSMo(=O)OH] active site as a third ligand. - Abstract: Carbon monoxide dehydrogenase (CO dehydrogenase) from Oligotropha carboxidovorans is a structurally characterized member of the molybdenum hydroxylase enzyme family. It catalyzes the oxidation of CO (CO + H{sub 2}O → CO{sub 2} + 2e{sup −} + 2H{sup +}) which proceeds at a unique [CuSMo(=O)OH] metal cluster. Because of changing activities of CO dehydrogenase, particularly in subcellular fractions, we speculated whether the enzyme would be subject to regulation by thiols (RSH). Here we establish inhibition of CO dehydrogenase by thiols and report the corresponding K{sub i}-values (mM): L-cysteine (5.2), D-cysteine (9.7), N-acetyl-L-cysteine (8.2), D,L-homocysteine (25.8), L-cysteine–glycine (2.0), dithiothreitol (4.1), coenzyme A (8.3), and 2-mercaptoethanol (9.3). Inhibition of the enzyme was reversed by CO or upon lowering the thiol concentration. Electron paramagnetic resonance spectroscopy (EPR) and X-ray absorption spectroscopy (XAS) of thiol-inhibited CO dehydrogenase revealed a bimetallic site in which the RSH coordinates to the Cu-ion as a third ligand ([Mo{sup VI}(=O)OH{sub (2)}SCu{sup I}(SR)S-Cys]) leaving the redox state of the Cu(I) and the Mo(VI) unchanged. Collectively, our findings establish a regulation of CO dehydrogenase activity by thiols in vitro. They also corroborate the hypothesis that CO interacts with the Cu-ion first. The result that thiol compounds much larger than CO can freely travel through the substrate channel leading to the bimetallic cluster challenges previous concepts involving chaperone function and is of importance for an understanding how the sulfuration step in

  17. Loss of peroxisomes causes oxygen insensitivity of the histochemical assay of glucose-6-phosphate dehydrogenase activity to detect cancer cells

    NARCIS (Netherlands)

    Frederiks, Wilma M.; Vreeling-Sindelárová, Heleen; van Noorden, Cornelis J. F.

    2007-01-01

    Oxygen insensitivity of carcinoma cells and oxygen sensitivity of non-cancer cells in the histochemical assay of glucose-6-phosphate dehydrogenase (G6PD) enables detection of carcinoma cells in unfixed cell smears or cryostat sections of biopsies. The metabolic background of oxygen insensitivity is

  18. Regenerative Capacity of Cacti Schlumbergera and Rhipsalidopsis in Relation to Endogenous Phytohormones, Cytokinin Oxidase/Dehydrogenase, and Peroxidase Activities

    Czech Academy of Sciences Publication Activity Database

    Sriskandarajah, S.; Prinsen, E.; Motyka, Václav; Dobrev, Petre; Serek, M.

    2006-01-01

    Roč. 25, č. 1 (2006), s. 79-88 ISSN 0721-7595 R&D Projects: GA ČR GA206/03/0313 Institutional research plan: CEZ:AV0Z50380511 Keywords : Cytokinin dehydrogenase * Cytokinin oxidase * Endogenous phytohormones * In vitro regeneration * Peroxidase * Rhipsalidopsis * Schlumbergera Subject RIV: EF - Botanics Impact factor: 2.107, year: 2006

  19. Activity of lactate dehydrogenase in serum and cerebral cortex of immature and mature rats after hypobaric hypoxia

    Czech Academy of Sciences Publication Activity Database

    Koudelová, J.; Rauchová, Hana; Vokurková, Martina

    2006-01-01

    Roč. 31, č. 7 (2006), s. 915-919 ISSN 0364-3190 R&D Projects: GA ČR(CZ) GA305/04/0500; GA MŠk(CZ) 1M0510 Institutional research plan: CEZ:AV0Z50110509 Keywords : brain * lactate dehydrogenase * hypoxia Subject RIV: ED - Physiology Impact factor: 2.139, year: 2006

  20. Characterization of 17α-hydroxysteroid dehydrogenase activity (17α-HSD and its involvement in the biosynthesis of epitestosterone

    Directory of Open Access Journals (Sweden)

    Breton Rock

    2005-07-01

    Full Text Available Abstract Background Epi-testosterone (epiT is the 17α-epimer of testosterone. It has been found at similar level as testosterone in human biological fluids. This steroid has thus been used as a natural internal standard for assessing testosterone abuse in sports. EpiT has been also shown to accumulate in mammary cyst fluid and in human prostate. It was found to possess antiandrogenic activity as well as neuroprotective effects. So far, the exact pathway leading to the formation of epiT has not been elucidated. Results In this report, we describe the isolation and characterization of the enzyme 17α-hydroxysteroid dehydrogenase. The name is given according to its most potent activity. Using cells stably expressing the enzyme, we show that 17α-HSD catalyzes efficienty the transformation of 4-androstenedione (4-dione, dehydroepiandrosterone (DHEA, 5α-androstane-3,17-dione (5α-dione and androsterone (ADT into their corresponding 17α-hydroxy-steroids : epiT, 5-androstene-3β,17α-diol (epi5diol, 5α-androstane-17α-ol-3-one (epiDHT and 5α-androstane-3α,17α-diol (epi3α-diol, respectively. Similar to other members of the aldo-keto reductase family that possess the ability to reduce the keto-group into hydroxyl-group at different position on the steroid nucleus, 17α-HSD could also catalyze the transformation of DHT, 5α-dione, and 5α-pregnane-3,20-dione (DHP into 3α-diol, ADT and 5α-pregnane-3α-ol-20-one (allopregnanolone through its less potent 3α-HSD activity. We also have over-expressed the 17α-HSD in Escherichia coli and have purified it by affinity chromatography. The purified enzyme exhibits the same catalytic properties that have been observed with cultured HEK-293 stably transfected cells. Using quantitative Realtime-PCR to study tissue distribution of this enzyme in the mouse, we observed that it is expressed at very high levels in the kidney. Conclusion The present study permits to clarify the biosynthesis pathway of epiT. It

  1. The activity of 11β-hydroxysteroid dehydrogenase type 2 enzyme and cortisol secretion in patients with adrenal incidentalomas.

    Science.gov (United States)

    Morelli, Valentina; Polledri, Elisa; Mercadante, Rosa; Zhukouskaya, Volha; Palmieri, Serena; Beck-Peccoz, Paolo; Spada, Anna; Fustinoni, Silvia; Chiodini, Iacopo

    2016-09-01

    In adrenal incidentaloma (AI) patients, beside the cortisol secretion, a different 11β-hydroxysteroid dehydrogenase type 2 (HSD11B2) activity, measurable by 24-h urinary cortisol/cortisone ratio (R-UFF/UFE) (the higher R-UFF/UFE the lower HSD11B2 activity), could influence the occurrence of the subclinical hypercortisolism (SH)-related complications (hypertension, type 2 diabetes, obesity). We evaluated whether in AI patients, UFF levels are associated to UFE levels, and the HSD11B2 activity to the complications presence. In 156 AI patients (93F, age 65.2 ± 9.5 years), the following were measured: serum cortisol after 1 mg-dexamethasone test (1 mg-DST), ACTH, UFF, UFE levels, and R-UFF/UFE (by liquid chromatography-tandem mass spectrometry), the latter was also evaluated in 63 matched-controls. We diagnosed SH (n = 22) in the presence of ≥2 among ACTH levels, and 1 mg-DST >83 nmol/L. Patients showed higher UFF levels and R-UFF/UFE than controls (75.9 ± 43.1 vs 54.4 ± 22.9 nmol/24 h and 0.26 ± 0.12 vs 0.20 ± 0.07, p levels (291 ± 91.1 vs 268 ± 61.5, p = 0.069). The R-UFF/UFE was higher in patients with high (h-UFF, n = 28, 0.41 ± 0.20) than in those with normal (n-UFF, 0.22 ± 0.10, p levels and in patients with SH than in those without SH (0.30 ± 0.12 vs 0.25 ± 0.12, p = 0.04). UFF levels were associated with R-UFF/UFE (r = 0.849, p levels in n-UFF patients but not in h-UFF patients, and it is not associated with the SH complications.

  2. Glucose-6-phosphate dehydrogenase and glutathione reductase activity in methemoglobin reduction by methylene blue and cyst amine: study on glucose-6-phosphate dehydrogenase-deficient individuals, on normal subjects and on riboflavin-treated subjects

    Directory of Open Access Journals (Sweden)

    Benedito Barraviera

    1988-10-01

    Full Text Available The authors have standardized methods for evaluation of the activity of the glucose-6-phosphate dehydrogenase and of glutathione reductase. The general principle of the first method was based on methemoglobin formation by sodium nitrite followed by stimulation of the glucose-6-phosphate dehydrogenase with methylene blue. Forty six adults (23 males and 23 females were studied. Subjects were not G6PD deficient and were aged 20 to 30 years. The results showed that methemoglobin reduction by methylene blue was 154.40 and 139.90 mg/min (p<0.05 for males and females, respectively, in whole blood, and 221.10 and 207.85 mg/min (n.s., respectively, in washed red cells. These data showed that using washed red cells and 0.7g% sodium nitrite concentration produced no differences between sexes and also shortened reading time for the residual amount of methemoglobin to 90 minutes. Glutathione reductase activity was evaluated on the basis of the fact that cystamine (a thiol agent binds to the SH groups of hemoglobin, forming complexes. These complexes are reversed by the action of glutathione reductase, with methemoglobin reduction occurring simultaneously with this reaction. Thirty two adults (16 males and 16 females were studied. Subjects were not G6PD deficient and were aged 20 to 30 years. Methemoglobin reduction by cystamine was 81.27 and 91.13 mg/min (p<0.01 for males and females, respectively. These data showed that using washed red cells and 0.1 M cystamine concentration permits a reading of the residual amount of methemoglobin at 180 minutes of incubation. Glutathione reductase activity was evaluated by methemoglobin reduction by cystamine in 14 females before and after treatment with 10 mg riboflavin per day for 8 days. The results were 73.69 and 94.26 jug/min (p<0.01 before and after treatment, showing that riboflavin treatment increase glutathione reductase activity even in normal individuals. Three Black G6PD-deficient individuals (2 males and 1

  3. Pharmacological activation of aldehyde dehydrogenase 2 promotes osteoblast differentiation via bone morphogenetic protein-2 and induces bone anabolic effect

    Energy Technology Data Exchange (ETDEWEB)

    Mittal, Monika; Pal, Subhashis; China, Shyamsundar Pal; Porwal, Konica [Division of Endocrinology and Centre for Research in Anabolic Skeletal Targets in Health and Illness (ASTHI), CSIR-Central Drug Research Institute, Lucknow 226031 (India); Dev, Kapil [Division of Medicinal and Process Chemistry, CSIR-Central Drug Research Institute, Lucknow 226031 (India); Shrivastava, Richa [Division of Toxicology, CSIR-Central Drug Research Institute, Lucknow 226031 (India); Raju, Kanumuri Siva Rama; Rashid, Mamunur [Pharmaceutics Division, CSIR-Central Drug Research Institute, Lucknow 226031 (India); Trivedi, Arun Kumar; Sanyal, Sabyasachi [Biochemistry Division, CSIR-Central Drug Research Institute, Lucknow 226031 (India); Wahajuddin, Muhammad [Pharmaceutics Division, CSIR-Central Drug Research Institute, Lucknow 226031 (India); Bhaduria, Smrati [Division of Toxicology, CSIR-Central Drug Research Institute, Lucknow 226031 (India); Maurya, Rakesh [Division of Medicinal and Process Chemistry, CSIR-Central Drug Research Institute, Lucknow 226031 (India); Chattopadhyay, Naibedya, E-mail: n_chattopadhyay@cdri.res.in [Division of Endocrinology and Centre for Research in Anabolic Skeletal Targets in Health and Illness (ASTHI), CSIR-Central Drug Research Institute, Lucknow 226031 (India)

    2017-02-01

    Aldehyde dehydrogenases (ALDHs) are a family of enzymes involved in detoxifying aldehydes. Previously, we reported that an ALDH inhibitor, disulfiram caused bone loss in rats and among ALDHs, osteoblast expressed only ALDH2. Loss-of-function mutation in ALDH2 gene is reported to cause bone loss in humans which suggested its importance in skeletal homeostasis. We thus studied whether activating ALDH2 by N-(1, 3-benzodioxol-5-ylmethyl)-2, 6-dichlorobenzamide (alda-1) had osteogenic effect. We found that alda-1 increased and acetaldehyde decreased the differentiation of rat primary osteoblasts and expressions of ALDH2 and bone morphogenetic protein-2 (BMP-2). Silencing ALDH2 in osteoblasts abolished the alda-1 effects. Further, alda-1 attenuated the acetaldehyde-induced lipid-peroxidation and oxidative stress. BMP-2 is essential for bone regeneration and alda-1 increased its expression in osteoblasts. We then showed that alda-1 (40 mg/kg dose) augmented bone regeneration at the fracture site with concomitant increase in BMP-2 protein compared with control. The osteogenic dose (40 mg/kg) of alda-1 attained a bone marrow concentration that was stimulatory for osteoblast differentiation, suggesting that the tissue concentration of alda-1 matched its pharmacologic effect. In addition, alda-1 promoted modeling-directed bone growth and peak bone mass achievement, and increased bone mass in adult rats which reiterated its osteogenic effect. In osteopenic ovariectomized (OVX) rats, alda-1 reversed trabecular osteopenia with attendant increase in serum osteogenic marker (procollagen type I N-terminal peptide) and decrease in oxidative stress. Alda-1 has no effect on liver and kidney function. We conclude that activating ALDH2 by alda-1 had an osteoanabolic effect involving increased osteoblastic BMP-2 production and decreased OVX-induced oxidative stress. - Highlights: • Alda-1 induced osteoblast differentiation that involved upregulation of ALDH2 and BMP-2 • Alda-1

  4. Basal levels of metabolic activity are elevated in Genetic Absence Epilepsy Rats from Strasbourg (GAERS): measurement of regional activity of cytochrome oxidase and lactate dehydrogenase by histochemistry.

    Science.gov (United States)

    Dufour, Franck; Koning, Estelle; Nehlig, Astrid

    2003-08-01

    The Genetic Absence Epilepsy Rats from Strasbourg (GAERS) are considered an isomorphic, predictive, and homologous model of human generalized absence epilepsy. It is characterized by the expression of spike-and-wave discharges in the thalamus and cortex. In this strain, basal regional rates of cerebral glucose utilization measured by the quantitative autoradiographic [(14)C]2-deoxyglucose technique display a widespread consistent increase compared to a selected strain of genetically nonepileptic rats (NE). In order to verify whether these high rates of glucose metabolism are paralleled by elevated activities of the enzymes of the glycolytic and tricarboxylic acid cycle pathways, we measured by histochemistry the regional activity of the two key enzymes of glucose metabolism, lactate dehydrogenase (LDH) for the anaerobic pathway and cytochrome oxidase (CO) for the aerobic pathway coupled to oxidative phosphorylation. CO and LDH activities were significantly higher in GAERS than in NE rats in 24 and 28 of the 30 brain regions studied, respectively. The differences in CO and LDH activity between both strains were widespread, affected all brain systems studied, and ranged from 12 to 63%. The data of the present study confirm the generalized increase in cerebral glucose metabolism in GAERS, occurring both at the glycolytic and at the oxidative step. However, they still do not allow us to understand why the ubiquitous mutation(s) generates spike-and-wave discharges only in the thalamocortical circuit.

  5. Effect of repeated pesticide applications on soil properties in cotton fields: II. Insecticide residues and impact on dehydrogenase and arginine deaminase activities

    International Nuclear Information System (INIS)

    Vig, K.; Singh, D.K.; Agarwal, H.C.; Dhawan, A.K.; Dureja, P.

    2001-01-01

    Insecticides were applied sequentially at recommended dosages post crop emergence in cotton fields and soil was sampled at regular intervals after each treatment. Soil was analysed for insecticide residues and activity of the enzymes dehydrogenase and arginine deaminase. Insecticide residues detected in the soil were in small quantities and they did not persist for long. Only endosulfan leached below 15 cm. Insecticides had only temporary effects on enzyme activities which disappeared either before the next insecticide treatment or by the end of the experimental period. (author)

  6. Comparison of endogenous cytokinins and cytokinin oxidase/dehydrogenase activity in germinating and thermoinhibited Tagetes minuta achenes

    Czech Academy of Sciences Publication Activity Database

    Stirk, W. A.; Novák, Ondřej; Žižková, Eva; Motyka, Václav; Strnad, Miroslav; van Staden, J.

    2012-01-01

    Roč. 169, č. 7 (2012), s. 696-703 ISSN 0176-1617 R&D Projects: GA MŠk(CZ) LC06034; GA ČR(CZ) GAP506/11/0774 Grant - others:GA MŠk(CZ) ED0007/01/01 Program:ED Institutional research plan: CEZ:AV0Z50380511 Keywords : cytokinin biosynthesis * cytokinin oxidase/dehydrogenase * deactivation Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.699, year: 2012

  7. Incorporation of /sup 14/C glucose into glycogen and glucose-6-phosphate dehydrogenase activity in rat brain following carbon monoxide intoxication

    Energy Technology Data Exchange (ETDEWEB)

    Sikorska, M; Gorzkowski, B; Szumanska, G; Smialek, M [Polska Akademia Nauk, Warsaw. Centrum Medycyny Doswiadczalnej i Klinicznej; Panstwowy Zaklad Higieny, Warsaw (Poland))

    1975-01-01

    Incorporation of /sup 14/C glucose into glycogen and glucose-6-phosphate dehydrogenase activity in rat brain following carbon monoxide intoxication was studied. In brains of rats tested on the 20, 30 and 60th minute of exposure to CO and immediately after removal from the chamber the enzyme activity showed no essential deviation from the control level. In the group of rats tested 1 hour after taking them out from the chamber increase of the enzyme activity was noticed, amounting to about 33% of the control value. The brains tested 24 hours after exposure showed the largest increase of the enzyme activity by about 94%. In the next time periods, 48 and 72 hours after intoxication, the enzyme activity was decreasing. The glycogen content in brains of control animals increased 3 hours after CO intoxication by about 69%. The increase of glycogen synthesis was expressed by increase of the total radioactivity, which amounted to 160% of the control value.

  8. Disease-causing missense mutations affect enzymatic activity, stability and oligomerization of glutaryl-CoA dehydrogenase (GCDH)

    DEFF Research Database (Denmark)

    Keyser, B.; Muhlhausen, C.; Dickmanns, A.

    2008-01-01

    Glutaric aciduria type 1 (GA1) is an autosomal recessive neurometabolic disorder caused by mutations in the glutaryl-CoA dehydrogenase gene (GCDH), leading to an accumulation and high excretion of glutaric acid and 3-hydroxyglutaric acid. Considerable variation in severity of the clinical phenotype......Da GCDH complexes. Molecular modeling of mutant GCDH suggests that Met263 at the surface of the GCDH protein might be part of the contact interface to interacting proteins. These results indicate that reduced intramitochondrial stability as well as the impaired formation of homo- and heteromeric GCDH...

  9. The effects of interaction between Nanoanatase TiO2 and bleomycin sulfateon the lactate dehydrogenase activity in vivo

    OpenAIRE

    Roshanak Ghafarian Zirak; Akram Lotfi; Masoud Saleh Moghadam

    2016-01-01

    Although it is known that Nano TiO2 can induce various toxicities, the effects of its interaction with organic and biological molecules are still unclear. In this study, the effects of Nanoanatase TiO2 on lactate dehydrogenase (LDH) alone and in the presence of bleomycin sulfate (BLM.S), as an organic chemical, were investigated. Three doses of Nano TiO2 (10, 100, 500 mg/Kg BW) were injected into the abdominal cavity of Balb/C mice for 24 h. In addition, a particular dose of BLM.S (120 mg/...

  10. Expression, purification, crystallization and preliminary X-ray analysis of wild-type and of an active-site mutant of glyceraldehyde-3-phosphate dehydrogenase from Campylobacter jejuni

    International Nuclear Information System (INIS)

    Tourigny, David S.; Elliott, Paul R.; Edgell, Louise J.; Hudson, Gregg M.; Moody, Peter C. E.

    2010-01-01

    The cloning, expression, purification, crystallization and preliminary X-ray analysis of wild-type and of an active-site mutant of C. jejuni glyceraldehyde-3-phosphate dehydrogenase is reported. The genome of the enteric pathogen Campylobacter jejuni encodes a single glyceraldehyde-3-phosphate dehydrogenase that can utilize either NADP + or NAD + as coenzymes for the oxidative phosphorylation of glyceraldehyde-3-phosphate to 1,3-diphosphoglycerate. Here, the cloning, expression, purification, crystallization and preliminary X-ray analysis of both the wild type and an active-site mutant of the enzyme are presented. Preliminary X-ray analysis revealed that in both cases the crystals diffracted to beyond 1.9 Å resolution. The space group is shown to be I4 1 22, with unit-cell parameters a = 90.75, b = 90.75, c = 225.48 Å, α = 90.46, β = 90.46, γ = 222.79°; each asymmetric unit contains only one subunit of the tetrameric enzyme

  11. INVERSE ELECTRON TRANSFER IN PEROXYOXALATE CHEMIEXCITATION USING EASILY REDUCIBLE ACTIVATORS

    NARCIS (Netherlands)

    Bartoloni, Fernando Heering; Monteiro Leite Ciscato, Luiz Francisco; Augusto, Felipe Alberto; Baader, Wilhelm Josef

    2010-01-01

    INVERSE ELECTRON TRANSFER IN PEROXYOXALATE CHEMIEXCITATION USING EASILY REDUCIBLE ACTIVATORS. Chemiluminescence properties of the peroxyoxalate reaction in the presence of activators bearing electron withdrawing substituents were studied, to evaluate the possible occurrence of an inverse electron

  12. Impaired hippocampal glucose metabolism during and after flurothyl-induced seizures in mice: Reduced phosphorylation coincides with reduced activity of pyruvate dehydrogenase.

    Science.gov (United States)

    McDonald, Tanya S; Borges, Karin

    2017-07-01

    To determine changes in glucose metabolism and the enzymes involved in the hippocampus ictally and postictally in the acute mouse flurothyl seizure model. [U- 13 C]-Glucose was injected (i.p.) prior to, or following a 5 min flurothyl-induced seizure. Fifteen minutes later, mice were killed and the total metabolite levels and % 13 C enrichment were analyzed in the hippocampal formation using gas chromatography-mass spectrometry. Activities of key metabolic and antioxidant enzymes and the phosphorylation status of pyruvate dehydrogenase were measured, along with lipid peroxidation. During seizures, total lactate levels increased 1.7-fold; however, [M + 3] enrichment of both lactate and alanine were reduced by 30% and 43%, respectively, along with a 28% decrease in phosphofructokinase activity. Postictally the % 13 C enrichments of all measured tricarboxylic acid (TCA) cycle intermediates and the amino acids were reduced by 46-93%. At this time, pyruvate dehydrogenase (PDH) activity was 56% of that measured in controls, and there was a 1.9-fold increase in the phosphorylation of PDH at ser232. Phosphorylation of PDH is known to decrease its activity. Here, we show that the increase of lactate levels during flurothyl seizures is from a source other than [U- 13 C]-glucose, such as glycogen. Surprisingly, although we saw a reduction in phosphofructokinase activity during the seizure, metabolism of [U- 13 C]-glucose into the TCA cycle seemed unaffected. Similar to our recent findings in the chronic phase of the pilocarpine model, postictally the metabolism of glucose by glycolysis and the TCA cycle was impaired along with reduced PDH activity. Although this decrease in activity may be a protective mechanism to reduce oxidative stress, which is observed in the flurothyl model, ATP is critical to the recovery of ion and neurotransmitter balance and return to normal brain function. Thus we identified promising novel strategies to enhance energy metabolism and recovery from

  13. Enhancement of L-3-hydroxybutyryl-CoA dehydrogenase activity and circulating ketone body levels by pantethine. Relevance to dopaminergic injury.

    Science.gov (United States)

    Cornille, Emilie; Abou-Hamdan, Mhamad; Khrestchatisky, Michel; Nieoullon, André; de Reggi, Max; Gharib, Bouchra

    2010-04-23

    The administration of the ketone bodies hydroxybutyrate and acetoacetate is known to exert a protective effect against metabolic disorders associated with cerebral pathologies. This suggests that the enhancement of their endogenous production might be a rational therapeutic approach. Ketone bodies are generated by fatty acid beta-oxidation, a process involving a mitochondrial oxido-reductase superfamily, with fatty acid-CoA thioesters as substrates. In this report, emphasis is on the penultimate step of the process, i.e. L-3-hydroxybutyryl-CoA dehydrogenase activity. We determined changes in enzyme activity and in circulating ketone body levels in the MPTP mouse model of Parkinson's disease. Since the active moiety of CoA is pantetheine, mice were treated with pantethine, its naturally-occurring form. Pantethine has the advantage of being known as an anti-inflammatory and hypolipidemic agent with very few side effects. We found that dehydrogenase activity and circulating ketone body levels were drastically reduced by the neurotoxin MPTP, whereas treatment with pantethine overcame these adverse effects. Pantethine prevented dopaminergic neuron loss and motility disorders. In vivo and in vitro experiments showed that the protection was associated with enhancement of glutathione (GSH) production as well as restoration of respiratory chain complex I activity and mitochondrial ATP levels. Remarkably, pantethine treatment boosted the circulating ketone body levels in MPTP-intoxicated mice, but not in normal animals. These finding demonstrate the feasibility of the enhancement of endogenous ketone body production and provide a promising therapeutic approach to Parkinson's disease as well as, conceivably, to other neurodegenerative disorders.

  14. Kinetic characterization of recombinant Bacillus coagulans FDP-activated l-lactate dehydrogenase expressed in Escherichia coli and its substrate specificity.

    Science.gov (United States)

    Jiang, Ting; Xu, Yanbing; Sun, Xiucheng; Zheng, Zhaojuan; Ouyang, Jia

    2014-03-01

    Bacillus coagulans is a homofermentative, acid-tolerant and thermophilic sporogenic lactic acid bacterium, which is capable of producing high yields of optically pure lactic acid. The l-(+)-lactate dehydrogenase (l-LDH) from B. coagulans is considered as an ideal biocatalyst for industrial production. In this study, the gene ldhL encoding a thermostable l-LDH was amplified from B. coagulans NL01 genomic DNA and successfully expressed in Escherichia coli BL21 (DE3). The recombinant enzyme was partially purified and its enzymatic properties were characterized. Sequence analysis demonstrated that the l-LDH was a fructose 1,6-diphosphate-activated NAD-dependent lactate dehydrogenase (l-nLDH). Its molecular weight was approximately 34-36kDa. The Km and Vmax values of the purified l-nLDH for pyruvate were 1.91±0.28mM and 2613.57±6.43μmol(minmg)(-1), respectively. The biochemical properties of l-nLDH showed that the specific activity were up to 2323.29U/mg with optimum temperature of 55°C and pH of 6.5 in the pyruvate reduction and 351.01U/mg with temperature of 55°C and pH of 11.5 in the lactate oxidation. The enzyme also showed some activity in the absence of FDP, with a pH optimum of 4.0. Compared to other lactic acid bacterial l-nLDHs, the enzyme was found to be relatively stable at 50°C. Ca(2+), Ba(2+), Mg(2+) and Mn(2+) ions had activated effects on the enzyme activity, and the enzyme was greatly inhibited by Ni(2+) ion. Besides these, l-nLDH showed the higher specificity towards pyruvate esters, such as methyl pyruvate and ethyl pyruvate. Copyright © 2014 Elsevier Inc. All rights reserved.

  15. Enhancement of L-3-hydroxybutyryl-CoA dehydrogenase activity and circulating ketone body levels by pantethine. Relevance to dopaminergic injury

    Directory of Open Access Journals (Sweden)

    de Reggi Max

    2010-04-01

    Full Text Available Abstract Background The administration of the ketone bodies hydroxybutyrate and acetoacetate is known to exert a protective effect against metabolic disorders associated with cerebral pathologies. This suggests that the enhancement of their endogenous production might be a rational therapeutic approach. Ketone bodies are generated by fatty acid beta-oxidation, a process involving a mitochondrial oxido-reductase superfamily, with fatty acid-CoA thioesters as substrates. In this report, emphasis is on the penultimate step of the process, i.e. L-3-hydroxybutyryl-CoA dehydrogenase activity. We determined changes in enzyme activity and in circulating ketone body levels in the MPTP mouse model of Parkinson's disease. Since the active moiety of CoA is pantetheine, mice were treated with pantethine, its naturally-occurring form. Pantethine has the advantage of being known as an anti-inflammatory and hypolipidemic agent with very few side effects. Results We found that dehydrogenase activity and circulating ketone body levels were drastically reduced by the neurotoxin MPTP, whereas treatment with pantethine overcame these adverse effects. Pantethine prevented dopaminergic neuron loss and motility disorders. In vivo and in vitro experiments showed that the protection was associated with enhancement of glutathione (GSH production as well as restoration of respiratory chain complex I activity and mitochondrial ATP levels. Remarkably, pantethine treatment boosted the circulating ketone body levels in MPTP-intoxicated mice, but not in normal animals. Conclusions These finding demonstrate the feasibility of the enhancement of endogenous ketone body production and provide a promising therapeutic approach to Parkinson's disease as well as, conceivably, to other neurodegenerative disorders.

  16. The influence of individualizing physical loads on speed, creatine kinase activity and lactate dehydrogenase in football players.

    Directory of Open Access Journals (Sweden)

    2008-06-01

    Full Text Available Introduction: One of the most important training problems in: contemporary football is speed preparation of a player for the season and the ability of keeping it on the same, relatively high level throughout the starting period [1]. The main process used for re-synthesis ATP during single, short-lasting efforts of maximal intensity, is decomposition of phospho-creatine under the influence of creatine kinase enzyme. Physical loads imposed during speed trainings often exceed the possibility of producing energy from phosphogenic reserve through oxygen - lactate free processes, because the supply of phospho-creatine is used very quickly. In such circumstances the lacking energy is refilled through processes called oxygen free glicolise with the help of lactate dehydrogenase enzyme. The aim of the work was to answer the question:

  17. Salicylic acid binding of mitochondrial alpha-ketoglutarate dehydrogenase E2 affects mitochondrial oxidative phosphorylation and electron transport chain components and plays a role in basal defense against tobacco mosaic virus in tomato.

    Science.gov (United States)

    Liao, Yangwenke; Tian, Miaoying; Zhang, Huan; Li, Xin; Wang, Yu; Xia, Xiaojian; Zhou, Jie; Zhou, Yanhong; Yu, Jingquan; Shi, Kai; Klessig, Daniel F

    2015-02-01

    Salicylic acid (SA) plays a critical role in plant defense against pathogen invasion. SA-induced viral defense in plants is distinct from the pathways mediating bacterial and fungal defense and involves a specific pathway mediated by mitochondria; however, the underlying mechanisms remain largely unknown. The SA-binding activity of the recombinant tomato (Solanum lycopersicum) alpha-ketoglutarate dehydrogenase (Slα-kGDH) E2 subunit of the tricarboxylic acid (TCA) cycle was characterized. The biological role of this binding in plant defenses against tobacco mosaic virus (TMV) was further investigated via Slα-kGDH E2 silencing and transient overexpression in plants. Slα-kGDH E2 was found to bind SA in two independent assays. SA treatment, as well as Slα-kGDH E2 silencing, increased resistance to TMV. SA did not further enhance TMV defense in Slα-kGDH E2-silenced tomato plants but did reduce TMV susceptibility in Nicotiana benthamiana plants transiently overexpressing Slα-kGDH E2. Furthermore, Slα-kGDH E2-silencing-induced TMV resistance was fully blocked by bongkrekic acid application and alternative oxidase 1a silencing. These results indicated that binding by Slα-kGDH E2 of SA acts upstream of and affects the mitochondrial electron transport chain, which plays an important role in basal defense against TMV. The findings of this study help to elucidate the mechanisms of SA-induced viral defense. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  18. Clinical implications of thymidylate synthetase, dihydropyrimidine dehydrogenase and orotate phosphoribosyl transferase activity levels in colorectal carcinoma following radical resection and administration of adjuvant 5-FU chemotherapy

    International Nuclear Information System (INIS)

    Ishikawa, Masashi; Miyauchi, Takayuki; Kashiwagi, Yutaka

    2008-01-01

    A number of studies have investigated whether the activity levels of enzymes involved in 5-fluorouracil (5-FU) metabolism are prognostic factors for survival in patients with colorectal carcinoma. Most reports have examined thymidylate synthetase (TS) and dihydropyrimidine dehydrogenase (DPD) in unresectable or metastatic cases, therefore it is unclear whether the activity of these enzymes is of prognostic value in colorectal cancer patients treated with radical resection and adjuvant chemotherapy with 5-FU. This study examined fresh frozen specimens of colorectal carcinoma from 40 patients who had undergone curative operation and were orally administered adjuvant tegafur/uracil (UFT) chemotherapy. TS, DPD and orotate phosphoribosyl transferase (OPRT) activities were assayed in cancer tissue and adjacent normal tissue and their association with clinicopathological variables was investigated. In addition, the relationships between TS, DPD and OPRT activities and patient survival were examined to determine whether any of these enzymes could be useful prognostic factors. While there was no clear relationship between pathological findings and TS or DPD activity, OPRT activity was significantly lower in tumors with lymph node metastasis than in tumors lacking lymph node metastasis. Postoperative survival was significantly better in the groups with low TS activity and/or high OPRT activity. TS and OPRT activity levels in tumor tissue may be important prognostic factors for survival in Dukes' B and C colorectal carcinoma with radical resection and adjuvant chemotherapy with UFT

  19. Shikimate dehydrogenase from Pinu sylvestris L. needles

    International Nuclear Information System (INIS)

    Osipov, V.I.; Shein, I.V.

    1986-01-01

    Shikimate dehydrogenase was isolated by extraction from pine needles and partially purified by fractionation with ammonium sulfate. In conifers, in contrast to other plants, all three isoenzymes of shikimate dehydrogenase exhibit activity not only with NADP + , but also with NAD + . The values of K/sub m/ for shikimate, when NADP + and NAD + are used as cofactors, are 0.22 and 1.13 mM, respectively. The enzyme is maximally active at pH 10 with both cofactors. It is suggested that NAD-dependent shikimate dehydrogenase catalyzes the initial reaction of the alternative pathway of the conversion of shikimic acid to hydroxybenzoic acid. The peculiarities of the organization and regulation of the initial reactions of the shikimate pathway in conifers and in plants with shikimate dehydrogenase absolutely specific for NADP are discussed

  20. The Enzyme Activity and Substrate Specificity of Two Major Cinnamyl Alcohol Dehydrogenases in Sorghum (Sorghum bicolor), SbCAD2 and SbCAD4.

    Science.gov (United States)

    Jun, Se-Young; Walker, Alexander M; Kim, Hoon; Ralph, John; Vermerris, Wilfred; Sattler, Scott E; Kang, ChulHee

    2017-08-01

    Cinnamyl alcohol dehydrogenase (CAD) catalyzes the final step in monolignol biosynthesis, reducing sinapaldehyde, coniferaldehyde, and p -coumaraldehyde to their corresponding alcohols in an NADPH-dependent manner. Because of its terminal location in monolignol biosynthesis, the variation in substrate specificity and activity of CAD can result in significant changes in overall composition and amount of lignin. Our in-depth characterization of two major CAD isoforms, SbCAD2 (Brown midrib 6 [bmr6]) and SbCAD4, in lignifying tissues of sorghum ( Sorghum bicolor ), a strategic plant for generating renewable chemicals and fuels, indicates their similarity in both structure and activity to Arabidopsis ( Arabidopsis thaliana ) CAD5 and Populus tremuloides sinapyl alcohol dehydrogenase, respectively. This first crystal structure of a monocot CAD combined with enzyme kinetic data and a catalytic model supported by site-directed mutagenesis allows full comparison with dicot CADs and elucidates the potential signature sequence for their substrate specificity and activity. The L119W/G301F-SbCAD4 double mutant displayed its substrate preference in the order coniferaldehyde > p -coumaraldehyde > sinapaldehyde, with higher catalytic efficiency than that of both wild-type SbCAD4 and SbCAD2. As SbCAD4 is the only major CAD isoform in bmr6 mutants, replacing SbCAD4 with L119W/G301F-SbCAD4 in bmr6 plants could produce a phenotype that is more amenable to biomass processing. © 2017 American Society of Plant Biologists. All Rights Reserved.

  1. Stilbene Glucoside, a Putative Sleep Promoting Constituent from Polygonum multiflorum Affects Sleep Homeostasis by Affecting the Activities of Lactate Dehydrogenase and Salivary Alpha Amylase.

    Science.gov (United States)

    Wei, Qian; Ta, Guang; He, Wenjing; Wang, Wei; Wu, Qiucheng

    2017-01-01

    Chinese herbal medicine (CHM) has been used for treating insomnia for centuries. The most used CHM for insomnia was Polygonum multiflorum. However, the molecular mechanism for CHM preventing insomnia is unknown. Stilbene glucoside (THSG), an important active component of P. multiflorum, may play an important role for treating insomnia. To test the hypothesis, Kunming mice were treated with different dosages of THSG. To examine the sleep duration, a computer-controlled sleep-wake detection system was implemented. Electroencephalogram (EEG) and electromyogram (EMG) electrodes were implanted to determine sleep-wake state. RT-PCR and Western blot was used to measure the levels of lactate dehydrogenase (LDH) and saliva alpha amylase. Spearman's rank correlation coefficient was used to identify the strength of correlation between the variables. The results showed that THSG significantly prolonged the sleep time of the mice (palpha amylase (palpha amylase (pamylase were negatively associated with sleep duration (palpha amylase.

  2. Structure of Cryptosporidium IMP dehydrogenase bound to an inhibitor with in vivo antiparasitic activity

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Youngchang; Makowska-Grzyska, Magdalena; Gorla, Suresh Kumar; Gollapalli, Deviprasad R.; Cuny, Gregory D.; Joachimiak, Andrzej; Hedstrom, Lizbeth

    2015-04-21

    Inosine 5'-monophosphate dehydrogenase (IMPDH) is a promising target for the treatment ofCryptosporidiuminfections. Here, the structure ofC. parvumIMPDH (CpIMPDH) in complex with inosine 5'-monophosphate (IMP) and P131, an inhibitor within vivoanticryptosporidial activity, is reported. P131 contains two aromatic groups, one of which interacts with the hypoxanthine ring of IMP, while the second interacts with the aromatic ring of a tyrosine in the adjacent subunit. In addition, the amine and NO2moieties bind in hydrated cavities, forming water-mediated hydrogen bonds to the protein. The design of compounds to replace these water molecules is a new strategy for the further optimization ofC. parvuminhibitors for both antiparasitic and antibacterial applications.

  3. Active pixel sensor array with electronic shuttering

    Science.gov (United States)

    Fossum, Eric R. (Inventor)

    2002-01-01

    An active pixel cell includes electronic shuttering capability. The cell can be shuttered to prevent additional charge accumulation. One mode transfers the current charge to a storage node that is blocked against accumulation of optical radiation. The charge is sampled from a floating node. Since the charge is stored, the node can be sampled at the beginning and the end of every cycle. Another aspect allows charge to spill out of the well whenever the charge amount gets higher than some amount, thereby providing anti blooming.

  4. Inhibition effects of furfural on alcohol dehydrogenase, aldehyde dehydrogenase and pyruvate dehydrogenase.

    Science.gov (United States)

    Modig, Tobias; Lidén, Gunnar; Taherzadeh, Mohammad J

    2002-01-01

    The kinetics of furfural inhibition of the enzymes alcohol dehydrogenase (ADH; EC 1.1.1.1), aldehyde dehydrogenase (AlDH; EC 1.2.1.5) and the pyruvate dehydrogenase (PDH) complex were studied in vitro. At a concentration of less than 2 mM furfural was found to decrease the activity of both PDH and AlDH by more than 90%, whereas the ADH activity decreased by less than 20% at the same concentration. Furfural inhibition of ADH and AlDH activities could be described well by a competitive inhibition model, whereas the inhibition of PDH was best described as non-competitive. The estimated K(m) value of AlDH for furfural was found to be about 5 microM, which was lower than that for acetaldehyde (10 microM). For ADH, however, the estimated K(m) value for furfural (1.2 mM) was higher than that for acetaldehyde (0.4 mM). The inhibition of the three enzymes by 5-hydroxymethylfurfural (HMF) was also measured. The inhibition caused by HMF of ADH was very similar to that caused by furfural. However, HMF did not inhibit either AlDH or PDH as severely as furfural. The inhibition effects on the three enzymes could well explain previously reported in vivo effects caused by furfural and HMF on the overall metabolism of Saccharomyces cerevisiae, suggesting a critical role of these enzymes in the observed inhibition. PMID:11964178

  5. Plant Formate Dehydrogenase

    Energy Technology Data Exchange (ETDEWEB)

    John Markwell

    2005-01-10

    The research in this study identified formate dehydrogenase, an enzyme that plays a metabolic role on the periphery of one-carbon metabolism, has an unusual localization in Arabidopsis thaliana and that the enzyme has an unusual kinetic plasticity. These properties make it possible that this enzyme could be engineered to attempt to engineer plants with an improved photosynthetic efficiency. We have produced transgenic Arabidopsis and tobacco plants with increased expression of the formate dehydrogenase enzyme to initiate further studies.

  6. Expression levels of chaperones influence biotransformation activity of recombinant Escherichia coli expressing Micrococcus luteus alcohol dehydrogenase and Pseudomonas putida Baeyer-Villiger monooxygenase.

    Science.gov (United States)

    Baek, A-Hyong; Jeon, Eun-Yeong; Lee, Sun-Mee; Park, Jin-Byung

    2015-05-01

    We demonstrated for the first time that the archaeal chaperones (i.e., γ-prefoldin and thermosome) can stabilize enzyme activity in vivo. Ricinoleic acid biotransformation activity of recombinant Escherichia coli expressing Micrococcus luteus alcohol dehydrogenase and the Pseudomonas putida KT2440 Baeyer-Villiger monooxygenase improved significantly with co-expression of γ-prefoldin or recombinant themosome originating from the deep-sea hyperthermophile archaea Methanocaldococcus jannaschii. Furthermore, the degree of enhanced activity was dependent on the expression levels of the chaperones. For example, whole-cell biotransformation activity was highest at 12 µmol/g dry cells/min when γ-prefoldin expression level was approximately 46% of the theoretical maximum. This value was approximately two-fold greater than that in E. coli, where the γ-prefoldin expression level was zero or set to the theoretical maximum. Therefore, it was assumed that the expression levels of chaperones must be optimized to achieve maximum biotransformation activity in whole-cell biocatalysts. © 2014 Wiley Periodicals, Inc.

  7. Ebselen protects against behavioral and biochemical toxicities induced by 3-nitropropionic acid in rats: correlations between motor coordination, reactive species levels, and succinate dehydrogenase activity.

    Science.gov (United States)

    Wilhelm, Ethel A; Bortolatto, Cristiani F; Jesse, Cristiano R; Luchese, Cristiane

    2014-12-01

    The protective effect of ebselen was investigated against 3-nitropropionic acid (3-NP)-induced behavioral and biochemical toxicities in rats. Ebselen (10 or 25 mg/kg, intragastrically) was administered to rats 30 min before 3-NP (20 mg/kg, intraperitoneally) once a day for a period of 4 days. Locomotor activity, motor coordination, and body weight gain were determined. The striatal content of reactive oxygen species (ROS), reduced glutathione (GSH), ascorbic acid (AA), and protein carbonyl as well as catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), and glutathione-S-transferase (GST) activities was determined 24 h after the last dose of 3-NP. Na(+)/ K(+)-ATPase, succinate dehydrogenase (SDH), and δ-aminolevulinic dehydratase (δ-ALA-D) activities were also determined. The results demonstrated that ebselen at a dose of 25 mg/kg, but not at 10 mg/kg, protected against (1) a decrease in locomotor activity, motor coordination impairment, and body weight loss; (2) striatal oxidative damage, which was characterized by an increase in ROS levels, protein carbonyl content, and GR activity, an inhibition of CAT and GPx activities, and a decrease in GSH levels; and (3) an inhibition of SDH and Na(+)/K(+)-ATPase activities, induced by 3-NP. GST activity and AA levels were not modified by ebselen or 3-NP. Ebselen was not effective against the inhibition of δ-ALA-D activity induced by 3-NP. The results revealed a significant correlation between SDH activity and ROS levels, and SDH activity and latency to fall (rotarod test). The present study highlighted the protective effect of ebselen against 3-NP-induced toxicity in rats.

  8. Phosphorylation site on yeast pyruvate dehydrogenase complex

    International Nuclear Information System (INIS)

    Uhlinger, D.J.

    1986-01-01

    The pyruvate dehydrogenase complex was purified to homogeneity from baker's yeast (Saccharomyces cerevisiae). Yeast cells were disrupted in a Manton-Gaulin laboratory homogenizer. The pyruvate dehydrogenase complex was purified by fractionation with polyethylene glycol, isoelectric precipitation, ultracentrifugation and chromatography on hydroxylapatite. Final purification of the yeast pyruvate dehydrogenase complex was achieved by cation-exchange high pressure liquid chromatography (HPLC). No endogenous pyruvate dehydrogenase kinase activity was detected during the purification. However, the yeast pyruvate dehydrogenase complex was phosphorylated and inactivated with purified pyruvate dehydrogenase kinase from bovine kidney. Tryptic digestion of the 32 P-labeled complex yielded a single phosphopeptide which was purified to homogeniety. The tryptic digest was subjected to chromatography on a C-18 reverse phase HPLC column with a linear gradient of acetonitrile. Radioactive fractions were pooled, concentrated, and subjected to anion-exchange HPLC. The column was developed with a linear gradient of ammonium acetate. Final purification of the phosphopeptide was achieved by chromatography on a C-18 reverse phase HPLC column developed with a linear gradient of acetonitrile. The amino acid sequence of the homogeneous peptide was determined by manual modified Edman degradation

  9. Active electronic personal dosemeter in interventional radiology

    International Nuclear Information System (INIS)

    Prlic, I.; Suric Mihic, M.; Vucic, Z.

    2008-01-01

    A recently developed active electronic personal dosemeter (AEPD) was utilised in order to measure the levels and the structure of occupational exposure to scattered X-ray radiation of medical staff who performed percutaneous revascularisation therapy that involves interventional radiology (IR) on the pelvis and upper leg arteries. The AEPDs, placed on the operators' and assistants' chests, that is, above the protective apron, continuously measured and recorded the received doses and, as a novelty, dose rates as a function of time, thus yielding a unique record of occupational doses and dose rates pattern at the working place. This paper presents and discusses one typical daily pattern in which seven percutaneous interventions were performed. (authors)

  10. Leucine-induced activation of translational initiation is partly regulated by the branched-chain α-keto acid dehydrogenase complex in C2C12 cells

    International Nuclear Information System (INIS)

    Nakai, Naoya; Shimomura, Yoshiharu; Tamura, Tomohiro; Tamura, Noriko; Hamada, Koichiro; Kawano, Fuminori; Ohira, Yoshinobu

    2006-01-01

    Branched-chain amino acid leucine has been shown to activate the translational regulators through the mammalian target of rapamycin. However, the leucine's effects are self-limiting because leucine promotes its own disposal by an oxidative pathway. The irreversible and rate-limiting step in the leucine oxidation pathway is catalyzed by the branched-chain α-keto acid dehydrogenase (BCKDH) complex. The complex contains E1 (α2β2), E2, and E3 subunits, and its activity is abolished by phosphorylation of the E1α subunit by BCKDH kinase. The relationship between the activity of BCKDH complex and leucine-mediated activation of the protein translation was investigated using the technique of RNA interference. The activity of BCKDH complex in C2C12 cell was modulated by transfection of small interfering RNA (siRNA) for BCKDH E2 subunit or BCKDH kinase. Transfection of siRNAs decreased the mRNA expression and protein amount of corresponding gene. Suppression of either E2 subunit or kinase produced opposite effects on the cell proliferation and the activation of translational regulators by leucine. Suppression of BCKDH kinase for 48 h resulted in decreasing cell proliferation. In contrast, E2 suppression led to increased amount of total cellular protein. The phosphorylation of p70 S6 kinase by leucine was increased in E2-siRNA transfected C2C12 cells, whereas the leucine's effect was diminished in kinase-siRNA transfected cells. These results suggest that the activation of the translational regulators by leucine was partly regulated by the activity of BCKDH complex

  11. Xylose reductase and xylitol dehydrogenase activities of Candida guilliermondii as a function of different treatments of sugarcane bagasse hemicellulosic hydrolysate employing experimental design.

    Science.gov (United States)

    Alves, Lourdes A; Vitolo, Michele; Felipe, Maria das Graças A; de Almeida e Silva, João Batista

    2002-01-01

    The sugarcane bagasse hydrolysate, which is rich in xylose, can be used as culture medium for Candida guilliermondii in xylitol production. However, the hydrolysate obtained from bagasse by acid hydrolysis at 120 degrees C for 20 min has by-products (acetic acid and furfural, among others), which are toxic to the yeast over certain concentrations. So, the hydrolysate must be pretreated before using in fermentation. The pretreatment variables considered were: adsorption time (15,37.5, and 60 min), type of acid used (H2So4 and H3Po4), hydrolysate concentration (original, twofold, and fourfold concentrated), and active charcoal (0.5, 1.75 and 3.0%). The suitability of the pretreatment was followed by measuring the xylose reductase (XR) and xylitol dehydrogenase (XD) activity of yeast grown in each treated hydrolysate. The response surface methodology (2(4) full factorial design with a centered face) indicated that the hydrolysate might be concentrated fourfold and the pH adjusted to 7.0 with CaO, followed by reduction to 5.5 with H3PO4. After that it was treated with active charcoal (3.0%) by 60 min. This pretreated hydrolysate attained the high XR/XD ratio of 4.5.

  12. aldB, an RpoS-dependent gene in Escherichia coli encoding an aldehyde dehydrogenase that is repressed by Fis and activated by Crp.

    OpenAIRE

    Xu, J; Johnson, R C

    1995-01-01

    Escherichia coli aldB was identified as a gene that is negatively regulated by Fis but positively regulated by RpoS. The complete DNA sequence determined in this study indicates that aldB encodes a 56.3-kDa protein which shares a high degree of homology with an acetaldehyde dehydrogenase encoded by acoD of Alcaligenes eutrophus and an aldehyde dehydrogenase encoded by aldA of Vibrio cholerae and significant homology with a group of other aldehyde dehydrogenases from prokaryotes and eukaryotes...

  13. Structures of the G81A mutant form of the active chimera of (S)-mandelate dehydrogenase and its complex with two of its substrates

    Energy Technology Data Exchange (ETDEWEB)

    Sukumar, Narayanasami [NE-CAT and Department of Chemistry and Chemical Biology, Cornell University, Building 436E, Argonne National Laboratory, Argonne, IL 60439 (United States); Dewanti, Asteriani [Department of Chemistry and Physics, Western Carolina University, Cullowhee, NC 28723 (United States); Merli, Angelo; Rossi, Gian Luigi [Department of Biochemistry and Molecular Biology, University of Parma, Parma (Italy); Mitra, Bharati [Department of Biochemistry and Molecular Biology, School of Medicine, Wayne State University, Detroit, MI 48201 (United States); Mathews, F. Scott, E-mail: mathews@biochem.wustl.edu [Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St Louis, MO 63110 (United States); NE-CAT and Department of Chemistry and Chemical Biology, Cornell University, Building 436E, Argonne National Laboratory, Argonne, IL 60439 (United States)

    2009-06-01

    The crystal structure of the G81A mutant form of the chimera of (S)-mandelate dehydrogenase and of its complexes with two of its substrates reveal productive and non-productive modes of binding for the catalytic reaction. The structure also indicates the role of G81A in lowering the redox potential of the flavin co-factor leading to an ∼200-fold slower catalytic rate of substrate oxidation. (S)-Mandelate dehydrogenase (MDH) from Pseudomonas putida, a membrane-associated flavoenzyme, catalyzes the oxidation of (S)-mandelate to benzoylformate. Previously, the structure of a catalytically similar chimera, MDH-GOX2, rendered soluble by the replacement of its membrane-binding segment with the corresponding segment of glycolate oxidase (GOX), was determined and found to be highly similar to that of GOX except within the substituted segments. Subsequent attempts to cocrystallize MDH-GOX2 with substrate proved unsuccessful. However, the G81A mutants of MDH and of MDH-GOX2 displayed ∼100-fold lower reactivity with substrate and a modestly higher reactivity towards molecular oxygen. In order to understand the effect of the mutation and to identify the mode of substrate binding in MDH-GOX2, a crystallographic investigation of the G81A mutant of the MDH-GOX2 enzyme was initiated. The structures of ligand-free G81A mutant MDH-GOX2 and of its complexes with the substrates 2-hydroxyoctanoate and 2-hydroxy-3-indolelactate were determined at 1.6, 2.5 and 2.2 Å resolution, respectively. In the ligand-free G81A mutant protein, a sulfate anion previously found at the active site is displaced by the alanine side chain introduced by the mutation. 2-Hydroxyoctanoate binds in an apparently productive mode for subsequent reaction, while 2-hydroxy-3-indolelactate is bound to the enzyme in an apparently unproductive mode. The results of this investigation suggest that a lowering of the polarity of the flavin environment resulting from the displacement of nearby water molecules caused by

  14. Simultaneous demonstration of acid phosphatase and glucose-6-phosphate dehydrogenase in mouse hepatocytes. A novel electron-microscopic dual staining enzyme-cytochemistry

    Directory of Open Access Journals (Sweden)

    S Matsubara

    2010-01-01

    Full Text Available Acid phosphatase (ACPase and glucose-6-phosphate dehydrogenase (G6PD play important roles in cell biology/disease pathophysiology in various organs including the liver. The purpose of the present report is to introduce a new enzymecytochemical method to simultaneously demonstrate the subcellular localization of ACPase and G6PD within the same hepatocyte in the mouse liver. The ultrastructural localization of ACPase and G6PD were demonstrated, with concomitant use of the cerium method and the copper-ferrocyanide method, respectively. ACPase labelings were localized in the lysosomes, and G6PD labelings were visible in the cytoplasm and on the cytosolic side of the endoplasmic reticulum of the hepatocyte. This novel double staining procedure may be a useful histochemical tool for the study of liver functions in both physiological and pathological conditions.

  15. Thermodynamic Basis of Electron Transfer in Dihydroorotate Dehydrogenase B from Lactococcus lactis:  Analysis by Potentiometry, EPR Spectroscopy, and ENDOR Spectroscopy

    DEFF Research Database (Denmark)

    Mohnsen, Al-Walid A.; Rigby, Stephen E. J.; Jensen, Kaj Frank

    2004-01-01

    Dihydroorotate dehydrogenase B (DHODB) is a complex iron-sulfur flavoprotein that catalyzes the conversion of dihydroorotate to orotate and the reduction of NAD+. The enzyme is a dimer of heterodimers containing an FMN, an FAD, and a 2Fe-2S center. UV-visible, EPR, and ENDOR spectroscopies have...... similar to those recorded for the blue semiquinone of free flavins in aqueous solution, thus confirming the presence of this species in DHODB. Spectral features observed during EPR spectroscopy of dithionite-reduced DHODB are consistent with the midpoint reduction potentials determined using UV-visible...... spectroscopy and further identify an unusual EPR signal with very small rhombic anisotropy and g values of 2.02, 1.99, and 1.96. This unusual signal is assigned to the formation of a spin interacting state between the FMN semiquinone species and the reduced 2Fe-2S center. Reduction of DHODB using an excess...

  16. Evaluation of Milk Trace Elements, Lactate Dehydrogenase, Alkaline Phosphatase and Aspartate Aminotransferase Activity of Subclinical Mastitis as and Indicator of Subclinical Mastitis in Riverine Buffalo (Bubalus bubalis).

    Science.gov (United States)

    Guha, Anirban; Gera, Sandeep; Sharma, Anshu

    2012-03-01

    Mastitis is a highly morbid disease that requires detection at the subclinical stage. Tropical countries like India mainly depend on milch buffaloes for milk. The present study was conducted to investigate whether the trace minerals viz. copper (Cu), iron (Fe), zinc (Zn), cobalt (Co) and manganese (Mn) and enzyme activity of lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and aspartate aminotransferase (AST) in riverine buffalo milk can be used as an indicator of subclinical mastitis (SCM) with the aim of developing suitable diagnostic kit for SCM. Trace elements and enzyme activity in milk were estimated with Atomic absorption Spectrophotometer, GBC 932 plus and biochemical methods, respectively. Somatic cell count (SCC) was done microscopically. The cultural examination revealed Gram positive bacteria as the most prevalent etiological agent. A statistically significant (pnegative bacteria. The percent sensitivity, specificity and accuracy, predictive values and likelihood ratios were calculated taking bacterial culture examination and SCC≥2×10(5) cells/ml of milk as the benchmark. Only ALP and Zn, the former being superior, were found to be suitable for diagnosis of SCM irrespective of etiological agents. LDH, Co and Fe can be introduced in the screening programs where Gram positive bacteria are omnipresent. It is recommended that both ALP and Zn be measured together in milk to diagnose buffalo SCM, irrespective of etiology.

  17. SIRT3 and SIRT5 regulate the enzyme activity and cardiolipin binding of very long-chain acyl-CoA dehydrogenase.

    Directory of Open Access Journals (Sweden)

    Yuxun Zhang

    Full Text Available SIRT3 and SIRT5 have been shown to regulate mitochondrial fatty acid oxidation but the molecular mechanisms behind the regulation are lacking. Here, we demonstrate that SIRT3 and SIRT5 both target human very long-chain acyl-CoA dehydrogenase (VLCAD, a key fatty acid oxidation enzyme. SIRT3 deacetylates and SIRT5 desuccinylates K299 which serves to stabilize the essential FAD cofactor in the active site. Further, we show that VLCAD binds strongly to cardiolipin and isolated mitochondrial membranes via a domain near the C-terminus containing lysines K482, K492, and K507. Acetylation or succinylation of these residues eliminates binding of VLCAD to cardiolipin. SIRT3 deacetylates K507 while SIRT5 desuccinylates K482, K492, and K507. Sirtuin deacylation of recombinant VLCAD rescues membrane binding. Endogenous VLCAD from SIRT3 and SIRT5 knockout mouse liver shows reduced binding to cardiolipin. Thus, SIRT3 and SIRT5 promote fatty acid oxidation by converging upon VLCAD to promote its activity and membrane localization. Regulation of cardiolipin binding by reversible lysine acylation is a novel mechanism that is predicted to extrapolate to other metabolic proteins that localize to the inner mitochondrial membrane.

  18. NADH:ubiquinone reductase and succinate dehydrogenase activity in the liver of rats with acetaminophen-induced toxic hepatitis on the background of alimentary protein deficiency

    Directory of Open Access Journals (Sweden)

    G. P. Kopylchuk

    2015-02-01

    Full Text Available The ratio between the redox forms of the nicotinamide coenzymes and key enzymatic activity of the I and II respiratory chain complexes in the liver cells mitochondria of rats with acetaminophen-induced hepatitis under the conditions of alimentary deprivation of protein was studied. It was estimated, that under the conditions of acute acetaminophen-induced hepatitis of rats kept on a low-protein diet during 4 weeks a significant decrease of the NADH:ubiquinone reductase and succinate dehydrogenase activity with simultaneous increase of the ratio between redox forms of the nicotinamide coenzymes (NAD+/NADН is observed compared to the same indices in the liver cells of animals with experimental hepatitis kept on the ration balanced by all nutrients. Results of research may become basic ones for the biochemical rationale for the approaches directed to the correction and elimination of the consequences­ of energy exchange in the toxic hepatitis, induced on the background of protein deficiency.

  19. S-Mercuration of rat sorbitol dehydrogenase by methylmercury causes its aggregation and the release of the zinc ion from the active site.

    Science.gov (United States)

    Kanda, Hironori; Toyama, Takashi; Shinohara-Kanda, Azusa; Iwamatsu, Akihiro; Shinkai, Yasuhiro; Kaji, Toshiyuki; Kikushima, Makoto; Kumagai, Yoshito

    2012-11-01

    We previously developed a screening method to identify proteins that undergo aggregation through S-mercuration by methylmercury (MeHg) and found that rat arginase I is a target protein for MeHg (Kanda et al. in Arch Toxicol 82:803-808, 2008). In the present study, we characterized another S-mercurated protein from a rat hepatic preparation that has a subunit mass of 42 kDa, thereby facilitating its aggregation. Two-dimensional SDS-polyacrylamide gel electrophoresis and subsequent peptide mass fingerprinting using matrix-assisted laser desorption and ionization time-of-flight mass spectrometry revealed that the 42 kDa protein was NAD-dependent sorbitol dehydrogenase (SDH). With recombinant rat SDH, we found that MeHg is covalently bound to SDH through Cys44, Cys119, Cys129 and Cys164, resulting in the inhibition of its catalytic activity, release of zinc ions and facilitates protein aggregation. Mutation analysis indicated that Cys44, which ligates the active site zinc atom, and Cys129 play a crucial role in the MeHg-mediated aggregation of SDH. Pretreatment with the cofactor NAD, but not NADP or FAD, markedly prevented aggregation of SDH. Such a protective effect of NAD on the aggregation of SDH caused by MeHg is discussed.

  20. Gastric alcohol dehydrogenase activity in man: influence of gender, age, alcohol consumption and smoking in a caucasian population

    DEFF Research Database (Denmark)

    Parlesak, Alexandr; Billinger, M. H.; Bode, C.

    2002-01-01

    potentially confounding factors (alcohol consumption, smoking, drug intake) on its activity in a Caucasian population. METHODS: ADH activity was assessed in endoscopic gastric biopsy specimens from 111 Caucasian subjects aged 20-80 years, of whom 51 were females. RESULTS: Highest ADH activity was measured...... at ethanol concentrations between 150 and 500 mM. Mean ADH activity was higher in antral specimens than in those from the gastric corpus of the same subjects. ADH activity decreased with increasing age in males, while the values in females aged 41-60 years were higher than those in women aged 20-40 or 61...... is negatively associated with consumption of larger quantities of alcohol. The question of whether ADH activity is higher in males or females can only be answered with respect to age. The gastric ADH activity in young men is distinctly higher compared to young women, but the opposite holds true in middle...

  1. Novel chiral tool, (R)-2-octanol dehydrogenase, from Pichia finlandica: purification, gene cloning, and application for optically active α-haloalcohols.

    Science.gov (United States)

    Yamamoto, Hiroaki; Kudoh, Masatake

    2013-09-01

    A novel enantioselective alcohol dehydrogenase, (R)-2-octanol dehydrogenase (PfODH), was discovered among methylotrophic microorganisms. The enzyme was purified from Pichia finlandica and characterized. The molecular mass of the enzyme was estimated to be 83,000 and 30,000 by gel filtration and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, respectively. The enzyme was an NAD(+)-dependent secondary alcohol dehydrogenase and showed a strict enantioselectivity, very broad substrate specificity, and high tolerance to SH reagents. A gene-encoding PfODH was cloned and sequenced. The gene consisted of 765 nucleotides, coding polypeptides of 254 amino acids. The gene was singly expressed and coexpressed together with a formate dehydrogenase as an NADH regenerator in an Escherichia coli. Ethyl (S)-4-chloro-3-hydroxybutanoate and (S)-2-chloro-1-phenylethanol were synthesized using a whole-cell biocatalyst in more than 99 % optical purity.

  2. Isoniazid acetylating phenotype in patients with paracoccidioidomycosis and its relationship with serum sulfadoxin levels, glucose-6-phosphate dehydrogenase and glutathione reductase activities

    Directory of Open Access Journals (Sweden)

    Benedito Barraviera

    1991-06-01

    Full Text Available The authors evaluated the isoniazid acetylating phenotype and measured hematocrit, hemoglobin, glucose-6-phosphate dehydrogenase and glutathione reductase activities plus serum sulfadoxin levels in 39 patients with paracoccidioidomycosis (33 males and 6 females aged 17 to 58 years. Twenty one (53.84% of the patients presented a slow acetylatingphenotype and 18(46.16% a fast acetylating phenotype. Glucose-6-phosphate- dehydrogenase (G6PD acti vity was decreased in 5(23.80% slow acetylators and in 4(22.22% fast acetylators. Glutathione reductase activity was decreased in 14 (66.66% slow acetylators and in 12 (66.66% fast acetylators. Serum levels of free and total sulfadoxin Were higher in slow acetylator (p Os autores avaliaram o fenótipo acetilador da isoniazida, hematócrito, hemoglobina, atividade da glicose-6- fosfato desidrogenase, glutationa redutase e os níveis séricos de sulfadoxina de 39 doentes com paracoccidíoidomicose, senão 33 do sexo masculino e 6 do feminino, com idades compreendidas entre 17 e 58 anos. Vinte e um (53,84% doentes apresentaram fenótipo acetilador lento e 18 (46,16% rápido. A atividade da glicose-6-fosfato desidrogenase (G6PD esteve diminuída em 5 (23,80% acetiladores lentos e 4 (22,22% rápidos. A atividade da glutationa redutase esteve diminuída em 14 (66,66% acetiladores lentos e 12 (66,66% rápidos. Os níveis séricos de sulfadoxina livre e total foram maiores nos acetiladores lentos (p < 0,02. A análise dos resultados permite concluir que os níveis séricos de sulfadoxina relaciona-se com o fenótipo acetilador. Além disso, os níveis estiveram sempre acima de 50 µg/ml, níveis estes considerados terapêuticos. Por outro lado, a deficiência de glutationa redutase pode estar relacionada com a má absorção intestinal de nutrientes, entre eles riboflavina, vitamina precursora de FAD.

  3. Increased superoxide accumulation in pyruvate dehydrogenase complex deficient fibroblasts.

    Science.gov (United States)

    Glushakova, Lyudmyla G; Judge, Sharon; Cruz, Alex; Pourang, Deena; Mathews, Clayton E; Stacpoole, Peter W

    2011-11-01

    The pyruvate dehydrogenase complex (PDC) oxidizes pyruvate to acetyl CoA and is critically important in maintaining normal cellular energy homeostasis. Loss-of-function mutations in PDC give rise to congenital lactic acidosis and to progressive cellular energy failure. However, the subsequent biochemical consequences of PDC deficiency that may contribute to the clinical manifestations of the disorder are poorly understood. We postulated that altered flux through PDC would disrupt mitochondrial electron transport, resulting in oxidative stress. Compared to cells from 4 healthy subjects, primary cultures of skin fibroblasts from 9 patients with variable mutations in the gene encoding the alpha subunit (E1α) of pyruvate dehydrogenase (PDA1) demonstrated reduced growth and viability. Superoxide (O(2)(.-)) from the Qo site of complex III of the electron transport chain accumulated in these cells and was associated with decreased activity of manganese superoxide dismutase. The expression of uncoupling protein 2 was also decreased in patient cells, but there were no significant changes in the expression of cellular markers of protein or DNA oxidative damage. The expression of hypoxia transcription factor 1 alpha (HIF1α) also increased in PDC deficient fibroblasts. We conclude that PDC deficiency is associated with an increase in O(2)(.-) accumulation coupled to a decrease in mechanisms responsible for its removal. Increased HIF1α expression may contribute to the increase in glycolytic flux and lactate production in PDC deficiency and, by trans-activating pyruvate dehydrogenase kinase, may further suppress residual PDC activity through phosphorylation of the E1α subunit. Copyright © 2011 Elsevier Inc. All rights reserved.

  4. The Ferredoxin-Like Proteins HydN and YsaA Enhance Redox Dye-Linked Activity of the Formate Dehydrogenase H Component of the Formate Hydrogenlyase Complex.

    Science.gov (United States)

    Pinske, Constanze

    2018-01-01

    Formate dehydrogenase H (FDH-H) and [NiFe]-hydrogenase 3 (Hyd-3) form the catalytic components of the hydrogen-producing formate hydrogenlyase (FHL) complex, which disproportionates formate to H 2 and CO 2 during mixed acid fermentation in enterobacteria. FHL comprises minimally seven proteins and little is understood about how this complex is assembled. Early studies identified a ferredoxin-like protein, HydN, as being involved in FDH-H assembly into the FHL complex. In order to understand how FDH-H and its small subunit HycB, which is also a ferredoxin-like protein, attach to the FHL complex, the possible roles of HydN and its paralogue, YsaA, in FHL complex stability and assembly were investigated. Deletion of the hycB gene reduced redox dye-mediated FDH-H activity to approximately 10%, abolished FHL-dependent H 2 -production, and reduced Hyd-3 activity. These data are consistent with HycB being an essential electron transfer component of the FHL complex. The FDH-H activity of the hydN and the ysaA deletion strains was reduced to 59 and 57% of the parental, while the double deletion reduced activity of FDH-H to 28% and the triple deletion with hycB to 1%. Remarkably, and in contrast to the hycB deletion, the absence of HydN and YsaA was without significant effect on FHL-dependent H 2 -production or total Hyd-3 activity; FDH-H protein levels were also unaltered. This is the first description of a phenotype for the E. coli ysaA deletion strain and identifies it as a novel factor required for optimal redox dye-linked FDH-H activity. A ysaA deletion strain could be complemented for FDH-H activity by hydN and ysaA , but the hydN deletion strain could not be complemented. Introduction of these plasmids did not affect H 2 production. Bacterial two-hybrid interactions showed that YsaA, HydN, and HycB interact with each other and with the FDH-H protein. Further novel anaerobic cross-interactions of 10 ferredoxin-like proteins in E. coli were also discovered and described

  5. Discovery of N-[2-[2-[[3-methoxy-4-(5-oxazolyl)phenyl]amino]-5-oxazolyl]phenyl]-N-methyl-4- morpholineacetamide as a novel and potent inhibitor of inosine monophosphate dehydrogenase with excellent in vivo activity.

    Science.gov (United States)

    Dhar, T G Murali; Shen, Zhongqi; Guo, Junqing; Liu, Chunjian; Watterson, Scott H; Gu, Henry H; Pitts, William J; Fleener, Catherine A; Rouleau, Katherine A; Sherbina, N Z; McIntyre, Kim W; Shuster, David J; Witmer, Mark R; Tredup, Jeffrey A; Chen, Bang-Chi; Zhao, Rulin; Bednarz, Mark S; Cheney, Daniel L; MacMaster, John F; Miller, Laura M; Berry, Karen K; Harper, Timothy W; Barrish, Joel C; Hollenbaugh, Diane L; Iwanowicz, Edwin J

    2002-05-23

    Inosine monophosphate dehydrogenase (IMPDH) is a key enzyme that is involved in the de novo synthesis of purine nucleotides. Novel 2-aminooxazoles were synthesized and tested for inhibition of IMPDH catalytic activity. Multiple analogues based on this chemotype were found to inhibit IMPDH with low nanomolar potency. One of the analogues (compound 23) showed excellent in vivo activity in the inhibition of antibody production in mice and in the adjuvant induced arthritis model in rats.

  6. Decreased 11β-Hydroxysteroid Dehydrogenase 1 Level and Activity in Murine Pancreatic Islets Caused by Insulin-Like Growth Factor I Overexpression.

    Directory of Open Access Journals (Sweden)

    Subrata Chowdhury

    Full Text Available We have reported a high expression of IGF-I in pancreatic islet β-cells of transgenic mice under the metallothionein promoter. cDNA microarray analysis of the islets revealed that the expression of 82 genes was significantly altered compared to wild-type mice. Of these, 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1, which is responsible for the conversion of inert cortisone (11-dehydrocorticosterone, DHC in rodents to active cortisol (corticosterone in the liver and adipose tissues, has not been identified previously as an IGF-I target in pancreatic islets. We characterized the changes in its protein level, enzyme activity and glucose-stimulated insulin secretion. In freshly isolated islets, the level of 11β-HSD1 protein was significantly lower in MT-IGF mice. Using dual-labeled immunofluorescence, 11β-HSD1 was observed exclusively in glucagon-producing, islet α-cells but at a lower level in transgenic vs. wild-type animals. MT-IGF islets also exhibited reduced enzymatic activities. Dexamethasone (DEX and DHC inhibited glucose-stimulated insulin secretion from freshly isolated islets of wild-type mice. In the islets of MT-IGF mice, 48-h pre-incubation of DEX caused a significant decrease in insulin release, while the effect of DHC was largely blunted consistent with diminished 11β-HSD1 activity. In order to establish the function of intracrine glucocorticoids, we overexpressed 11β-HSD1 cDNA in MIN6 insulinoma cells, which together with DHC caused apoptosis and a significant decrease in proliferation. Both effects were abolished with the treatment of an 11β-HSD1 inhibitor. Our results demonstrate an inhibitory effect of IGF-I on 11β-HSD1 expression and activity within the pancreatic islets, which may mediate part of the IGF-I effects on cell proliferation, survival and insulin secretion.

  7. Elevation of 11β-hydroxysteroid dehydrogenase type 2 activity in Holocaust survivor offspring: evidence for an intergenerational effect of maternal trauma exposure.

    Science.gov (United States)

    Bierer, Linda M; Bader, Heather N; Daskalakis, Nikolaos P; Lehrner, Amy L; Makotkine, Iouri; Seckl, Jonathan R; Yehuda, Rachel

    2014-10-01

    Adult offspring of Holocaust survivors comprise an informative cohort in which to study intergenerational transmission of the effects of trauma exposure. Lower cortisol and enhanced glucocorticoid sensitivity have been previously demonstrated in Holocaust survivors with PTSD, and in offspring of Holocaust survivors in association with maternal PTSD. In other work, reduction in the activity of the enzyme 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD-2), which inactivates cortisol, was identified in Holocaust survivors in comparison to age-matched, unexposed Jewish controls. Therefore, we investigated glucocorticoid metabolism in offspring of Holocaust survivors to evaluate if similar enzymatic decrements would be observed that might help to explain glucocorticoid alterations previously shown for Holocaust offspring. Holocaust offspring (n=85) and comparison subjects (n=27) were evaluated with clinical diagnostic interview and self-rating scales, and asked to collect a 24-h urine sample from which concentrations of cortisol and glucocorticoid metabolites were assayed by GCMS. 11β-HSD-2 activity was determined as the ratio of urinary cortisone to cortisol. Significantly reduced cortisol excretion was observed in Holocaust offspring compared to controls (p=.046), as had been shown for Holocaust survivors. However, 11β-HSD-2 activity was elevated for offspring compared to controls (p=.008), particularly among those whose mothers had been children, rather than adolescents or adults, during World War II (p=.032). The effect of paternal Holocaust exposure could not be reliably investigated in the current sample. The inverse association of offspring 11β-HSD-2 activity with maternal age at Holocaust exposure is consistent with the influence of glucocorticoid programming. Whereas a long standing reduction in 11β-HSD-2 activity among survivors is readily interpreted in the context of Holocaust related deprivation, understanding the directional effect on offspring will

  8. Purification and characterization of the amine dehydrogenase from a facultative methylotroph.

    Science.gov (United States)

    Coleman, J P; Perry, J J

    1984-01-01

    Strain RA-6 is a pink-pigmented organism which can grow on a variety of substrates including methylamine. It can utilize methylamine as sole source of carbon via an isocitrate lyase negative serine pathway. Methylamine grown cells contain an inducible primary amine dehydrogenase [primary amine: (acceptor) oxidoreductase (deaminating)] which is not present in succinate grown cells. The amine dehydrogenase was purified to over 90% homogeneity. It is an acidic protein (isoelectric point of 5.37) with a molecular weight of 118,000 containing subunits with approximate molecular weights of 16,500 and 46,000. It is active on an array of primary terminal amines and is strongly inhibited by carbonyl reagents. Cytochrome c or artificial electron acceptors are required for activity; neither NAD nor NADP can serve as primary electron acceptor.

  9. Antitrypanosomal compounds from the essential oil and extracts of Keetia leucantha leaves with inhibitor activity on Trypanosoma brucei glyceraldehyde-3-phosphate dehydrogenase.

    Science.gov (United States)

    Bero, J; Beaufay, C; Hannaert, V; Hérent, M-F; Michels, P A; Quetin-Leclercq, J

    2013-02-15

    Keetia leucantha is a West African tree used in traditional medicine to treat several diseases among which parasitic infections. The dichloromethane extract of leaves was previously shown to possess growth-inhibitory activities on Plasmodium falciparum, Trypanosoma brucei brucei and Leishmania mexicana mexicana with low or no cytotoxicity (>100 μg/ml on human normal fibroblasts) (Bero et al. 2009, 2011). In continuation of our investigations on the antitrypanosomal compounds from this dichloromethane extract, we analyzed by GC-FID and GC-MS the essential oil of its leaves obtained by hydrodistillation and the major triterpenic acids in this extract by LC-MS. Twenty-seven compounds were identified in the oil whose percentages were calculated using the normalization method. The essential oil, seven of its constituents and the three triterpenic acids were evaluated for their antitrypanosomal activity on Trypanosoma brucei brucei bloodstream forms (Tbb BSF) and procyclic forms (Tbb PF) to identify an activity on the glycolytic process of trypanosomes. The oil showed an IC(50) of 20.9 μg/ml on Tbb BSF and no activity was observed on Tbb PF. The best antitrypanosomal activity was observed for ursolic acid with IC(50) of 2.5 and 6.5 μg/ml respectively on Tbb BSF and Tbb PF. The inhibitory activity on a glycolytic enzyme of T. brucei, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), was also evaluated for betulinic acid, olenaolic acid, ursolic acid, phytol, α-ionone and β-ionone. The three triterpenic acids and β-ionone showed inhibitory activities on GAPDH with oleanolic acid being the most active with an inhibition of 72.63% at 20 μg/ml. This paper reports for the first time the composition and antitrypanosomal activity of the essential oil of Keetia leucantha. Several of its constituents and three triterpenic acids present in the dichloromethane leaves extract showed a higher antitrypanosomal activity on bloodstream forms of Tbb as compared to procyclic forms

  10. Effects of organic solvents on the enzyme activity of Trypanosoma cruzi glyceraldehyde-3-phosphate dehydrogenase in calorimetric assays

    DEFF Research Database (Denmark)

    Wiggers, Henrik; Cheleski, J; Zottis, A

    2007-01-01

    .0% for MeOH and up to 7.5% for DMSO. The results show that when GAPDH is assayed in the presence of DMSO (5%, v/v) using the ITC experiment, the enzyme exhibits approximately twofold higher activity than that of GAPDH with no cosolvent added. When MeOH (5%, v/v) is the cosolvent, the GAPDH activity......In drug discovery programs, dimethyl sulfoxide (DMSO) is a standard solvent widely used in biochemical assays. Despite the extensive use and study of enzymes in the presence of organic solvents, for some enzymes the effect of organic solvent is unknown. Macromolecular targets may be affected...... by the presence of different solvents in such a way that conformational changes perturb their active site structure accompanied by dramatic variations in activity when performing biochemical screenings. To address this issue, in this work we studied the effects of two organic solvents, DMSO and methanol (Me...

  11. Site-directed mutagenesis under the direction of in silico protein docking modeling reveals the active site residues of 3-ketosteroid-Δ1-dehydrogenase from Mycobacterium neoaurum.

    Science.gov (United States)

    Qin, Ning; Shen, Yanbing; Yang, Xu; Su, Liqiu; Tang, Rui; Li, Wei; Wang, Min

    2017-07-01

    3-Ketosteroid-Δ 1 -dehydrogenases (KsdD) from Mycobacterium neoaurum could transform androst-4-ene-3,17-dione (AD) to androst-1,4-diene-3,17-dione. This reaction has a significant effect on the product of pharmaceutical steroid. The crystal structure and active site residues information of KsdD from Mycobacterium is not yet available, which result in the engineering of KsdD is tedious. In this study, by the way of protein modeling and site-directed mutagenesis, we find that, Y122, Y125, S138, E140 and Y541 from the FAD-binding domain and Y365 from the catalytic domain play a key role in this transformation. Compared with the wild type, the decline in AD conversion for mutants illustrated that Y125, Y365, and Y541 were essential to the function of KsdD. Y122, S138 and E140 contributed to the catalysis of KsdD. The following analysis revealed the catalysis mechanism of these mutations in KsdD of Mycobacterium. These information presented here facilitate the manipulation of the catalytic properties of the enzyme to improve its application in the pharmaceutical steroid industry.

  12. The level of glucose-6-phosphate dehydrogenase activity strongly influences xylose fermentation and inhibitor sensitivity in recombinant Saccharomyces cerevisiae strains

    DEFF Research Database (Denmark)

    Jeppsson, M.; Johansson, B.; Jensen, Peter Ruhdal

    2003-01-01

    production levels of G6PDH on xylose fermentation. We used a synthetic promoter library and the copper-regulated CUP1 promoter to generate G6PDH-activities between 0% and 179% of the wildtype level. G6PDH-activities of 1% and 6% of the wild-type level resulted in 2.8- and 5.1-fold increase in specific xylose...

  13. Cloning and expression analysis of alcohol dehydrogenase ( Adh ...

    African Journals Online (AJOL)

    Hybrid promoters are created by shuffling of DNA fragments while keeping intact regulatory regions crucial of promoter activity. Two fragments of alcohol dehydrogenase (Adh) promoter from Zea mays were selected to generate hybrid promoter. Sequence analysis of both alcohol dehydrogenase promoter fragments through ...

  14. Some Properties of Glutamate Dehydrogenase from the Marine Red ...

    African Journals Online (AJOL)

    Keywords: ammonia assimilation, glutamate dehydrogenase, GDH, Gracilaria sordida, red alga, enzyme activity. Glutamate dehydrogenases (GDH, EC ... Anabolic functions could be assimilation of ammonia released during photorespiration and synthesis of N-rich transport compounds. Western Indian Ocean Journal of ...

  15. A simple and sensitive method for lactose detection based on direct electron transfer between immobilised cellobiose dehydrogenase and screen-printed carbon electrodes

    International Nuclear Information System (INIS)

    Safina, Gulnara; Ludwig, Roland; Gorton, Lo

    2010-01-01

    A rapid and simple approach of lactose analysis is proposed based on 3rd generation amperometric biosensors employing cellobiose dehydrogenase (CDH) from Trametes villosa or Phanerochaete sordida immobilised on screen-printed carbon electrodes (SPCEs). After optimisation of the working conditions of the biosensors - pH of the carrier buffer, flow rate and applied potential - the sensors were able to detect lactose in a concentration range between 0.5-200 μM and 0.5-100 μM employing T. villosa and P. sordida CDH, respectively. The limit of detection is 250 nM (90 μg/L) for both. Biosensors based on SPCEs modified with multiwalled carbon nanotubes showed a higher sensitivity than unmodified SPCEs. Cross-linking with glutaraldehyde or poly(ethyleneglycol)diglycidyl ether improved not only the stability but also the analytical response. The developed sensor has been successfully applied for the determination of lactose in dairy (milk with different percentages of fat, lactose-free milk and yogurt) with a good reproducibility (RSD = 1.5-2.2%). No sample preparation except a simple dilution process is needed. The biosensor is easy to make and operate, is inexpensive and reveals a high sensitivity and reliability.

  16. A simple and sensitive method for lactose detection based on direct electron transfer between immobilised cellobiose dehydrogenase and screen-printed carbon electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Safina, Gulnara, E-mail: Gulnara.Safina@chem.gu.s [Department of Analytical Chemistry/Biochemistry, Lund University, Box 124, 221 00 Lund (Sweden); Ludwig, Roland [Department of Analytical Chemistry/Biochemistry, Lund University, Box 124, 221 00 Lund (Sweden); Research Centre Applied Biocatalysis, Petersgasse 18, 8010 Graz (Austria); Gorton, Lo, E-mail: Lo.Gorton@biochemistry.lu.s [Department of Analytical Chemistry/Biochemistry, Lund University, Box 124, 221 00 Lund (Sweden)

    2010-11-01

    A rapid and simple approach of lactose analysis is proposed based on 3rd generation amperometric biosensors employing cellobiose dehydrogenase (CDH) from Trametes villosa or Phanerochaete sordida immobilised on screen-printed carbon electrodes (SPCEs). After optimisation of the working conditions of the biosensors - pH of the carrier buffer, flow rate and applied potential - the sensors were able to detect lactose in a concentration range between 0.5-200 {mu}M and 0.5-100 {mu}M employing T. villosa and P. sordida CDH, respectively. The limit of detection is 250 nM (90 {mu}g/L) for both. Biosensors based on SPCEs modified with multiwalled carbon nanotubes showed a higher sensitivity than unmodified SPCEs. Cross-linking with glutaraldehyde or poly(ethyleneglycol)diglycidyl ether improved not only the stability but also the analytical response. The developed sensor has been successfully applied for the determination of lactose in dairy (milk with different percentages of fat, lactose-free milk and yogurt) with a good reproducibility (RSD = 1.5-2.2%). No sample preparation except a simple dilution process is needed. The biosensor is easy to make and operate, is inexpensive and reveals a high sensitivity and reliability.

  17. Hypoxanthine-guanine phosphoribosyltransferase and inosine 5’-monophosphate dehydrogenase activities in three mammalian species: aquatic (Mirounga angustirostris, semiaquatic (Lontra longicaudis annectens and terrestrial (Sus scrofa

    Directory of Open Access Journals (Sweden)

    Myrna eBarjau Perez-Milicua

    2015-07-01

    Full Text Available Aquatic and semiaquatic mammals have the capacity of breath hold (apnea diving. Northern elephant seals (Mirounga angustirostris have the ability to perform deep and long duration dives; during a routine dive, adults can hold their breath for 25 min. Neotropical river otters (Lontra longicaudis annectens can hold their breath for about 30 sec. Such periods of apnea may result in reduced oxygen concentration (hypoxia and reduced blood supply (ischemia to tissues. Production of adenosine 5’-triphosphate (ATP requires oxygen, and most mammalian species, like the domestic pig (Sus scrofa, are not adapted to tolerate hypoxia and ischemia, conditions that result in ATP degradation. The objective of this study was to explore the differences in purine synthesis and recycling in erythrocytes and plasma of three mammalian species adapted to different environments: aquatic (northern elephant seal (n=11, semiaquatic (neotropical river otter (n=4 and terrestrial (domestic pig (n=11. Enzymatic activity of hypoxanthine-guanine phosphoribosyltransferase (HGPRT was determined by spectrophotometry, and activity of inosine 5’-monophosphate dehydrogenase (IMPDH and the concentration of hypoxanthine (HX, inosine 5’-monophosphate (IMP, adenosine 5’-monophosphate (AMP, adenosine 5’-diphosphate (ADP, ATP, guanosine 5’-diphosphate (GDP, guanosine 5’-triphosphate (GTP, and xanthosine 5’-monophosphate (XMP were determined by high-performance liquid chromatography (HPLC. The activities of HGPRT and IMPDH and the concentration of HX, IMP, AMP, ADP, ATP, GTP and XMP in erythrocytes of domestic pigs were higher than in erythrocytes of northern elephant seals and river otters. These results suggest that under basal conditions (no diving, sleep apnea or exercise, aquatic and semiaquatic mammals have less purine mobilization than their terrestrial counterparts.

  18. Selective inhibition of sheep kidney 11 beta-hydroxysteroid dehydrogenase isoform 2 activity by 5 alpha-reduced (but not 5 beta) derivatives of adrenocorticosteroids.

    Science.gov (United States)

    Latif, S A; Sheff, M F; Ribeiro, C E; Morris, D J

    1997-02-01

    We have previously reported that 5 alpha and 5 beta pathways of steroid metabolism are controlled in vivo by dietary Na+ and glycyrrhetinic acid, see Gorsline et al. 1988; Latif et al. 1990. The present investigations provide evidence supporting the suggestion that endogenous substances may regulate the glucocorticoid inactivating isoenzymes, 11 beta-HSD (hydroxysteroid dehydrogenase) 1 (liver) and 11 beta-HSD2 (kidney). The activity of 11 beta-HSD is impaired in essential hypertension, following licorice ingestion, and in patients with apparent mineralocorticoid excess where 11 beta-HSD2 is particularly affected. In all three conditions, excretion of the less common 5 alpha metabolites is elevated in urine. We now report on the differential abilities of a series of Ring A reduced (5 alpha and 5 beta) adrenocorticosteroid and progesterone metabolites to inhibit these isoenzymes. Using liver microsomes with NADP+ as co-factor (11 beta-HSD1), and sheep kidney microsomes with NAD+ as co-factor (11 beta-HSD2), we have systematically investigated the abilities of a number of adrenocorticosteroids and their derivatives to inhibit the individual isoforms of 11 beta-HSD. A striking feature is the differential sensitivity of the two isoenzymes to inhibition by 5 alpha and 5 beta derivatives. 11 beta-HSD1 is inhibited by both 5 alpha and certain 5 beta derivatives. 11 beta-HSD-2 was selectively inhibited only by 5 alpha derivatives: 5 beta derivatives were without inhibitory activity toward this isoform of 11 beta-HSD. These results indicate the importance of the structural conformation of the A and B Rings in conferring specific inhibitory properties on these compounds. In addition, we discuss the effects of additions or substitutions of other functional groups on the inhibitory potency of these steroid molecules against 11 beta-HSD1 and 11 beta-HSD2.

  19. Directed modification of L-LcLDH1, an L-lactate dehydrogenase from Lactobacillus casei, to improve its specific activity and catalytic efficiency towards phenylpyruvic acid.

    Science.gov (United States)

    Li, Jian-Fang; Li, Xue-Qing; Liu, Yan; Yuan, Feng-Jiao; Zhang, Ting; Wu, Min-Chen; Zhang, Ji-Ru

    2018-05-22

    To improve the specific activity and catalytic efficiency of L-LcLDH1, an NADH-dependent allosteric L-lactate dehydrogenase from L. casei, towards phenylpyruvic acid (PPA), its directed modification was conducted based on the semi-rational design. The three variant genes, Lcldh1 Q88R , Lcldh1 I229A and Lcldh1 T235G , were constructed by whole-plasmid PCR as designed theoretically, and expressed in E. coli BL21(DE3), respectively. The purified mutant, L-LcLDH1 Q88R or L-LcLDH1 I229A , displayed the specific activity of 451.5 or 512.4 U/mg towards PPA, by which the asymmetric reduction of PPA afforded L-phenyllactic acid (PLA) with an enantiomeric excess (ee p ) more than 99%. Their catalytic efficiencies (k cat /K m ) without D-fructose-1,6-diphosphate (D-FDP) were 4.8- and 5.2-fold that of L-LcLDH1. Additionally, the k cat /K m values of L-LcLDH1 Q88R and L-LcLDH1 I229A with D-FDP were 168.4- and 8.5-fold higher than those of the same enzymes without D-FDP, respectively. The analysis of catalytic mechanisms by molecular docking (MD) simulation indicated that substituting I229 in L-LcLDH1 with Ala enlarges the space of substrate-binding pocket, and that the replacement of Q88 with Arg makes the inlet of pocket larger than that of L-LcLDH1. Copyright © 2018 Elsevier B.V. All rights reserved.

  20. Effects of Betaine Aldehyde Dehydrogenase-Transgenic Soybean on Phosphatase Activities and Rhizospheric Bacterial Community of the Saline-Alkali Soil

    Directory of Open Access Journals (Sweden)

    Ying Nie

    2016-01-01

    Full Text Available The development of transgenic soybean has produced numerous economic benefits; however the potential impact of root exudates upon soil ecological systems and rhizospheric soil microbial diversity has also received intensive attention. In the present study, the influence of saline-alkali tolerant transgenic soybean of betaine aldehyde dehydrogenase on bacterial community structure and soil phosphatase during growth stages was investigated. The results showed that, compared with nontransgenic soybean as a control, the rhizospheric soil pH of transgenic soybean significantly decreased at the seedling stage. Compared to HN35, organic P content was 13.5% and 25.4% greater at the pod-filling stage and maturity, respectively. The acid phosphatase activity of SRTS was significantly better than HN35 by 12.74% at seedling, 14.03% at flowering, and 59.29% at podding, while alkaline phosphatase achieved maximum activity in the flowering stage and was markedly lower than HN35 by 13.25% at pod-filling. The 454 pyrosequencing technique was employed to investigate bacterial diversity, with a total of 25,499 operational taxonomic units (OTUs obtained from the 10 samples. Notably, the effect of SRTS on microbial richness and diversity of rhizospheric soil was marked at the stage of podding and pod-filling. Proteobacteria, Acidobacteria, and Actinobacteria were the dominant phyla among all samples. Compared with HN35, the relative abundance of Proteobacteria was lower by 2.01%, 2.06%, and 5.28% at the stage of seedling, at pod-bearing, and at maturity. In genus level, the relative abundance of Gp6, Sphingomonas sp., and GP4 was significantly inhibited by SRTS at the stage of pod-bearing and pod-filling.

  1. Association of Genetically Determined Aldehyde Dehydrogenase 2 Activity with Diabetic Complications in Relation to Alcohol Consumption in Japanese Patients with Type 2 Diabetes Mellitus: The Fukuoka Diabetes Registry.

    Directory of Open Access Journals (Sweden)

    Yasuhiro Idewaki

    Full Text Available Aldehyde dehydrogenase 2 (ALDH2 detoxifies aldehyde produced during ethanol metabolism and oxidative stress. A genetic defect in this enzyme is common in East Asians and determines alcohol consumption behaviors. We investigated the impact of genetically determined ALDH2 activity on diabetic microvascular and macrovascular complications in relation to drinking habits in Japanese patients with type 2 diabetes mellitus. An ALDH2 single-nucleotide polymorphism (rs671 was genotyped in 4,400 patients. Additionally, the relationship of clinical characteristics with ALDH2 activity (ALDH2 *1/*1 active enzyme activity vs. *1/*2 or *2/*2 inactive enzyme activity and drinking habits (lifetime abstainers vs. former or current drinkers was investigated cross-sectionally (n = 691 in *1/*1 abstainers, n = 1,315 in abstainers with *2, n = 1,711 in *1/*1 drinkers, n = 683 in drinkers with *2. The multiple logistic regression analysis for diabetic complications was adjusted for age, sex, current smoking habits, leisure-time physical activity, depressive symptoms, diabetes duration, body mass index, hemoglobin A1c, insulin use, high-density lipoprotein cholesterol, systolic blood pressure and renin-angiotensin system inhibitors use. Albuminuria prevalence was significantly lower in the drinkers with *2 than that of other groups (odds ratio [95% confidence interval (CI]: *1/*1 abstainers as the referent, 0.94 [0.76-1.16] in abstainers with *2, 1.00 [0.80-1.26] in *1/*1 drinkers, 0.71 [0.54-0.93] in drinkers with *2. Retinal photocoagulation prevalence was also lower in drinkers with ALDH2 *2 than that of other groups. In contrast, myocardial infarction was significantly increased in ALDH2 *2 carriers compared with that in ALDH2 *1/*1 abstainers (odds ratio [95% CI]: *1/*1 abstainers as the referent, 2.63 [1.28-6.13] in abstainers with *2, 1.89 [0.89-4.51] in *1/*1 drinkers, 2.35 [1.06-5.79] in drinkers with *2. In summary, patients with type 2 diabetes and ALDH2 *2

  2. Hibernation impact on the catalytic activities of the mitochondrial D-3-hydroxybutyrate dehydrogenase in liver and brain tissues of jerboa (Jaculus orientalis

    Directory of Open Access Journals (Sweden)

    Hafiani Assia

    2003-09-01

    Full Text Available Abstract Background Jerboa (Jaculus orientalis is a deep hibernating rodent native to subdesert highlands. During hibernation, a high level of ketone bodies i.e. acetoacetate (AcAc and D-3-hydroxybutyrate (BOH are produced in liver, which are used in brain as energetic fuel. These compounds are bioconverted by mitochondrial D-3-hydroxybutyrate dehydrogenase (BDH E.C. 1.1.1.30. Here we report, the function and the expression of BDH in terms of catalytic activities, kinetic parameters, levels of protein and mRNA in both tissues i.e brain and liver, in relation to the hibernating process. Results We found that: 1/ In euthemic jerboa the specific activity in liver is 2.4- and 6.4- fold higher than in brain, respectively for AcAc reduction and for BOH oxidation. The same differences were found in the hibernation state. 2/ In euthermic jerboa, the Michaelis constants, KM BOH and KM NAD+ are different in liver and in brain while KM AcAc, KM NADH and the dissociation constants, KD NAD+and KD NADH are similar. 3/ During prehibernating state, as compared to euthermic state, the liver BDH activity is reduced by half, while kinetic constants are strongly increased except KD NAD+. 4/ During hibernating state, BDH activity is significantly enhanced, moreover, kinetic constants (KM and KD are strongly modified as compared to the euthermic state; i.e. KD NAD+ in liver and KM AcAc in brain decrease 5 and 3 times respectively, while KD NADH in brain strongly increases up to 5.6 fold. 5/ Both protein content and mRNA level of BDH remain unchanged during the cold adaptation process. Conclusions These results cumulatively explained and are consistent with the existence of two BDH enzymatic forms in the liver and the brain. The apoenzyme would be subjected to differential conformational folding depending on the hibernation state. This regulation could be a result of either post-translational modifications and/or a modification of the mitochondrial membrane state

  3. Active Pixel Sensors for electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Denes, P. [Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)], E-mail: pdenes@lbl.gov; Bussat, J.-M. [Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States); Lee, Z.; Radmillovic, V. [National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2007-09-01

    The technology used for monolithic CMOS imagers, popular for cell phone cameras and other photographic applications, has been explored for charged particle tracking by the high-energy physics community for several years. This technology also lends itself to certain imaging detector applications in electron microscopy. We have been developing such detectors for several years at Lawrence Berkeley National Laboratory, and we and others have shown that this technology can offer excellent point-spread function, direct detection and high readout speed. In this paper, we describe some of the design constraints peculiar to electron microscopy and summarize where such detectors could play a useful role.

  4. Electron-beam-induced-current and active secondary-electron voltage-contrast with aberration-corrected electron probes

    Energy Technology Data Exchange (ETDEWEB)

    Han, Myung-Geun, E-mail: mghan@bnl.gov [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Garlow, Joseph A. [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Materials Science and Engineering Department, Stony Brook University, Stony Brook, NY 11794 (United States); Marshall, Matthew S.J.; Tiano, Amanda L. [Department of Chemistry, Stony Brook University, Stony Brook, NY 11974 (United States); Wong, Stanislaus S. [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Department of Chemistry, Stony Brook University, Stony Brook, NY 11974 (United States); Cheong, Sang-Wook [Department of Physics and Astronomy, Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ 08854 (United States); Walker, Frederick J.; Ahn, Charles H. [Department of Applied Physics and Center for Research on Interface Structures and Phenomena, Yale University, New Haven, CT 06520 (United States); Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06520 (United States); Zhu, Yimei [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2017-05-15

    Highlights: • Electron-beam-induced-current (EBIC) and active secondary-electron voltage-contrast (SE-VC) are demonstrated in STEM mode combined with in situ electrical biasing in a TEM. • Electrostatic potential maps in ferroelectric thin films, multiferroic nanowires, and single crystals obtained by off-axis electron holography were compared with EBIC and SE-VC data. • Simultaneous EBIC and active SE-VC performed with atomic resolution STEM are demonstrated. - Abstract: The ability to map out electrostatic potentials in materials is critical for the development and the design of nanoscale electronic and spintronic devices in modern industry. Electron holography has been an important tool for revealing electric and magnetic field distributions in microelectronics and magnetic-based memory devices, however, its utility is hindered by several practical constraints, such as charging artifacts and limitations in sensitivity and in field of view. In this article, we report electron-beam-induced-current (EBIC) and secondary-electron voltage-contrast (SE-VC) with an aberration-corrected electron probe in a transmission electron microscope (TEM), as complementary techniques to electron holography, to measure electric fields and surface potentials, respectively. These two techniques were applied to ferroelectric thin films, multiferroic nanowires, and single crystals. Electrostatic potential maps obtained by off-axis electron holography were compared with EBIC and SE-VC to show that these techniques can be used as a complementary approach to validate quantitative results obtained from electron holography analysis.

  5. Glucose-6-phosphate dehydrogenase (G6PD)-deficient infants: Enzyme activity and gene variants as risk factors for phototherapy in the first week of life.

    Science.gov (United States)

    Wong, Fei-Liang; Ithnin, Azlin; Othman, Ainoon; Cheah, Fook-Choe

    2017-07-01

    Glucose-6-phosphate dehydrogenase (G6PD) deficiency is a recognised cause of severe neonatal hyperbilirubinaemia, and identifying which infants are at risk could optimise care and resources. In this study, we determined if G6PD enzyme activity (EA) and certain gene variants were associated with neonatal hyperbilirubinaemia requiring phototherapy during the first week after birth. Newborn infants with G6PD deficiency and a group with normal results obtained by the fluorescent spot test were selected for analyses of G6PD EA and the 10 commonly encountered G6PD mutations in this region, relating these with whether the infants required phototherapy before discharge from the hospital in the first week. A total of 222 infants with mean gestation and birth weight of 38.3 ± 1.8 weeks and 3.02 ± 0.48 kg, respectively, were enrolled. Of these, n = 121 were deficient with EA ≤6.76 U/g Hb, and approximately half (43%) received phototherapy in the first week after birth. The mean EA level was 3.7 U/g Hb. The EA had good accuracy in predicting phototherapy use, with area under the receiver-operating-characteristic curve of 0.81 ± 0.05. Infants on phototherapy more commonly displayed World Health Organization Class II mutations (deficiency in EA and mutation at c.1388G>A (adjusted odds ratio, 1.5 and 5.7; 95% confidence interval: 1.31-1.76 and 1.30-25.0, respectively) were independent risk factors for phototherapy. Low G6PD EA (G6PD gene variant, c.1388G>A, are risk factors for the need of phototherapy in newborn infants during the first week after birth. © 2017 Paediatrics and Child Health Division (The Royal Australasian College of Physicians).

  6. Electron Correlation Models for Optical Activity

    DEFF Research Database (Denmark)

    Höhn, E. G.; O. E. Weigang, Jr.

    1968-01-01

    A two-system no-overlap model for rotatory strength is developed for electric-dipole forbidden as well as allowed transitions. General equations which allow for full utilization of symmetry in the chromophore and in the environment are obtained. The electron correlation terms are developed in full...

  7. Quantitative cytochemical analysis of glucose-6-phosphate dehydrogenase activity in living isolated hepatocytes of European flounder for rapid analysis of xenobiotic effects

    NARCIS (Netherlands)

    Winzer, K.; van Noorden, C. J.; Köhler, A.

    2001-01-01

    There is a great need for rapid but reliable assays to determine quantitatively effects of xenobiotics on biological systems in environmental research. Hepatocytes of European flounder are sensitive to low-dose toxic stress. Glucose-6-phosphate dehydrogenase (G6PDH) is the major source of NADPH in

  8. Host cell and expression engineering for development of an E. coli ketoreductase catalyst: Enhancement of formate dehydrogenase activity for regeneration of NADH

    Directory of Open Access Journals (Sweden)

    Mädje Katharina

    2012-01-01

    Full Text Available Abstract Background Enzymatic NADH or NADPH-dependent reduction is a widely applied approach for the synthesis of optically active organic compounds. The overall biocatalytic conversion usually involves in situ regeneration of the expensive NAD(PH. Oxidation of formate to carbon dioxide, catalyzed by formate dehydrogenase (EC 1.2.1.2; FDH, presents an almost ideal process solution for coenzyme regeneration that has been well established for NADH. Because isolated FDH is relatively unstable under a range of process conditions, whole cells often constitute the preferred form of the biocatalyst, combining the advantage of enzyme protection in the cellular environment with ease of enzyme production. However, the most prominent FDH used in biotransformations, the enzyme from the yeast Candida boidinii, is usually expressed in limiting amounts of activity in the prime host for whole cell biocatalysis, Escherichia coli. We therefore performed expression engineering with the aim of enhancing FDH activity in an E. coli ketoreductase catalyst. The benefit resulting from improved NADH regeneration capacity is demonstrated in two transformations of technological relevance: xylose conversion into xylitol, and synthesis of (S-1-(2-chlorophenylethanol from o-chloroacetophenone. Results As compared to individual expression of C. boidinii FDH in E. coli BL21 (DE3 that gave an intracellular enzyme activity of 400 units/gCDW, co-expression of the FDH with the ketoreductase (Candida tenuis xylose reductase; XR resulted in a substantial decline in FDH activity. The remaining FDH activity of only 85 U/gCDW was strongly limiting the overall catalytic activity of the whole cell system. Combined effects from increase in FDH gene copy number, supply of rare tRNAs in a Rosetta strain of E. coli, dampened expression of the ketoreductase, and induction at low temperature (18°C brought up the FDH activity threefold to a level of 250 U/gCDW while reducing the XR activity by

  9. Structural complexities in the active layers of organic electronics.

    Science.gov (United States)

    Lee, Stephanie S; Loo, Yueh-Lin

    2010-01-01

    The field of organic electronics has progressed rapidly in recent years. However, understanding the direct structure-function relationships between the morphology in electrically active layers and the performance of devices composed of these materials has proven difficult. The morphology of active layers in organic electronics is inherently complex, with heterogeneities existing across multiple length scales, from subnanometer to micron and millimeter range. A major challenge still facing the organic electronics community is understanding how the morphology across all of the length scales in active layers collectively determines the device performance of organic electronics. In this review we highlight experiments that have contributed to the elucidation of structure-function relationships in organic electronics and also point to areas in which knowledge of such relationships is still lacking. Such knowledge will lead to the ability to select active materials on the basis of their inherent properties for the fabrication of devices with prespecified characteristics.

  10. Probing the dynamic interface between trimethylamine dehydrogenase (TMADH) and electron transferring flavoprotein (ETF) in the TMADH-2ETF complex: role of the Arg-alpha237 (ETF) and Tyr-442 (TMADH) residue pair.

    Science.gov (United States)

    Burgess, Selena G; Messiha, Hanan Latif; Katona, Gergely; Rigby, Stephen E J; Leys, David; Scrutton, Nigel S

    2008-05-06

    We have used multiple solution state techniques and crystallographic analysis to investigate the importance of a putative transient interaction formed between Arg-alpha237 in electron transferring flavoprotein (ETF) and Tyr-442 in trimethylamine dehydrogenase (TMADH) in complex assembly, electron transfer, and structural imprinting of ETF by TMADH. We have isolated four mutant forms of ETF altered in the identity of the residue at position 237 (alphaR237A, alphaR237K, alphaR237C, and alphaR237E) and with each form studied electron transfer from TMADH to ETF, investigated the reduction potentials of the bound ETF cofactor, and analyzed complex formation. We show that mutation of Arg-alpha237 substantially destabilizes the semiquinone couple of the bound FAD and impedes electron transfer from TMADH to ETF. Crystallographic structures of the mutant ETF proteins indicate that mutation does not perturb the overall structure of ETF, but leads to disruption of an electrostatic network at an ETF domain boundary that likely affects the dynamic properties of ETF in the crystal and in solution. We show that Arg-alpha237 is required for TMADH to structurally imprint the as-purified semiquinone form of wild-type ETF and that the ability of TMADH to facilitate this structural reorganization is lost following (i) redox cycling of ETF, or simple conversion to the oxidized form, and (ii) mutagenesis of Arg-alpha237. We discuss this result in light of recent apparent conflict in the literature relating to the structural imprinting of wild-type ETF. Our studies support a mechanism of electron transfer by conformational sampling as advanced from our previous analysis of the crystal structure of the TMADH-2ETF complex [Leys, D. , Basran, J. , Sutcliffe, M. J., and Scrutton, N. S. (2003) Nature Struct. Biol. 10, 219-225] and point to a key role for the Tyr-442 (TMADH) and Arg-alpha237 (ETF) residue pair in transiently stabilizing productive electron transfer configurations. Our work

  11. Promysalin Elicits Species-Selective Inhibition of Pseudomonas aeruginosa by Targeting Succinate Dehydrogenase.

    Science.gov (United States)

    Keohane, Colleen E; Steele, Andrew D; Fetzer, Christian; Khowsathit, Jittasak; Van Tyne, Daria; Moynié, Lucile; Gilmore, Michael S; Karanicolas, John; Sieber, Stephan A; Wuest, William M

    2018-02-07

    Natural products have served as an inspiration to scientists both for their complex three-dimensional architecture and exquisite biological activity. Promysalin is one such Pseudomonad secondary metabolite that exhibits narrow-spectrum antibacterial activity, originally isolated from the rhizosphere. We herein utilize affinity-based protein profiling (AfBPP) to identify succinate dehydrogenase (Sdh) as the biological target of the natural product. The target was further validated in silico, in vitro, in vivo, and through the selection, and sequencing, of a resistant mutant. Succinate dehydrogenase plays an essential role in primary metabolism of Pseudomonas aeruginosa as the only enzyme that is involved both in the tricarboxylic acid cycle (TCA) and in respiration via the electron transport chain. These findings add credence to other studies that suggest that the TCA cycle is an understudied target in the development of novel therapeutics to combat P. aeruginosa, a significant pathogen in clinical settings.

  12. NirN Protein from Pseudomonas aeruginosa is a Novel Electron-bifurcating Dehydrogenase Catalyzing the Last Step of Heme d1 Biosynthesis*

    Science.gov (United States)

    Adamczack, Julia; Hoffmann, Martin; Papke, Ulrich; Haufschildt, Kristin; Nicke, Tristan; Bröring, Martin; Sezer, Murat; Weimar, Rebecca; Kuhlmann, Uwe; Hildebrandt, Peter; Layer, Gunhild

    2014-01-01

    Heme d1 plays an important role in denitrification as the essential cofactor of the cytochrome cd1 nitrite reductase NirS. At present, the biosynthesis of heme d1 is only partially understood. The last step of heme d1 biosynthesis requires a so far unknown enzyme that catalyzes the introduction of a double bond into one of the propionate side chains of the tetrapyrrole yielding the corresponding acrylate side chain. In this study, we show that a Pseudomonas aeruginosa PAO1 strain lacking the NirN protein does not produce heme d1. Instead, the NirS purified from this strain contains the heme d1 precursor dihydro-heme d1 lacking the acrylic double bond, as indicated by UV-visible absorption spectroscopy and resonance Raman spectroscopy. Furthermore, the dihydro-heme d1 was extracted from purified NirS and characterized by UV-visible absorption spectroscopy and finally identified by high-resolution electrospray ionization mass spectrometry. Moreover, we show that purified NirN from P. aeruginosa binds the dihydro-heme d1 and catalyzes the introduction of the acrylic double bond in vitro. Strikingly, NirN uses an electron bifurcation mechanism for the two-electron oxidation reaction, during which one electron ends up on its heme c cofactor and the second electron reduces the substrate/product from the ferric to the ferrous state. On the basis of our results, we propose novel roles for the proteins NirN and NirF during the biosynthesis of heme d1. PMID:25204657

  13. Rapid synthesis of triazine inhibitors of inosine monophosphate dehydrogenase.

    Science.gov (United States)

    Pitts, William J; Guo, Junqing; Dhar, T G Murali; Shen, Zhongqi; Gu, Henry H; Watterson, Scott H; Bednarz, Mark S; Chen, Bang Chi; Barrish, Joel C; Bassolino, Donna; Cheney, Daniel; Fleener, Catherine A; Rouleau, Katherine A; Hollenbaugh, Diane L; Iwanowicz, Edwin J

    2002-08-19

    A series of novel triazine-based small molecule inhibitors (IV) of inosine monophosphate dehydrogenase was prepared. The synthesis and the structure-activity relationships (SAR) derived from in vitro studies are described.

  14. Novel amide-based inhibitors of inosine 5'-monophosphate dehydrogenase.

    Science.gov (United States)

    Watterson, Scott H; Liu, Chunjian; Dhar, T G Murali; Gu, Henry H; Pitts, William J; Barrish, Joel C; Fleener, Catherine A; Rouleau, Katherine; Sherbina, N Z; Hollenbaugh, Diane L; Iwanowicz, Edwin J

    2002-10-21

    A series of novel amide-based small molecule inhibitors of inosine monophosphate dehydrogenase (IMPDH) was explored. The synthesis and the structure-activity relationships (SARs) derived from in vitro studies are described.

  15. Cortisol metabolism in healthy young adults: sexual dimorphism in activities of A-ring reductases, but not 11beta-hydroxysteroid dehydrogenases.

    Science.gov (United States)

    Finken, M J; Andrews, R C; Andrew, R; Walker, B R

    1999-09-01

    Cortisol is metabolized irreversibly by A-ring reductases (5alpha- and 5beta-reductases) and reversibly (to cortisone) by 11beta-hydroxysteroid dehydrogenases (11betaHSDs). In rats, estradiol down-regulates 11betaHSD1 expression. In humans, ratios of urinary cortisol/cortisone metabolites differ in men and women. In this study, urinary cortisol metabolites and hepatic 11betaHSD1 activity were measured in healthy young men and women at different phases of the menstrual cycle. Ten men and 10 women with regular menstrual cycles collected a 24-h urine sample, took 250 microg oral dexamethasone at 2300 h, took 25 mg oral cortisone at 0900 h (after fasting), and had blood sampled for plasma cortisol estimation over the subsequent 150 min. Women repeated the tests in random order in menstrual, follicular, and luteal phases. Women excreted disproportionately less A-ring-reduced metabolites of cortisol [median 5alpha-tetrahydrocortisol, 1811 (interquartile range, 1391-2300) microg/day in menstrual phase vs. 2723 (interquartile range, 2454-3154) in men (P = 0.01); 5beta-tetrahydrocortisol, 1600 (interquartile range, 1419-1968) vs. 2197 (interquartile range, 1748-2995; P = 0.03)] but similar amounts of cortisol, cortisone, and tetrahydrocortisone. Analogous differences were observed in urinary excretion of androgen metabolites. Conversion of cortisone to cortisol on hepatic first pass metabolism was not different (peak plasma cortisol, 733 +/- 60 nmol/L in women vs. 684 +/- 53 nmol/L in men; mean +/- SEM; P = 0.55). There were no differences in cortisol or androgen metabolism between phases of the menstrual cycle. We conclude that sexual dimorphism in cortisol metabolite excretion is attributable to less A-ring reduction of cortisol in women, rather than less reactivation of cortisone to cortisol by 11betaHSD1. This difference is not influenced acutely by gonadal steroids. 11BetaHSD1 has been suggested to modulate insulin sensitivity and body fat distribution, but caution

  16. Effect of exogenous cytokinins, auxins and adenine on cytokinin N-glucosylation and cytokinin oxidase/dehydrogenase activity in de-rooted radish seedlings

    Czech Academy of Sciences Publication Activity Database

    Blagoeva, Elitsa; Dobrev, Petre; Malbeck, Jiří; Motyka, Václav; Gaudinová, Alena; Vaňková, Radomíra

    2004-01-01

    Roč. 44, č. 1 (2004), s. 15-23 ISSN 0167-6903 R&D Projects: GA ČR GA522/99/1130; GA AV ČR IAA6038002; GA MŠk LN00A081; GA MŠk ME 505 Institutional research plan: CEZ:AV0Z5038910 Keywords : Auxin * Cytokinin * Cytokinin oxidase/dehydrogenase Subject RIV: GE - Plant Breeding Impact factor: 0.693, year: 2004

  17. aldB, an RpoS-dependent gene in Escherichia coli encoding an aldehyde dehydrogenase that is repressed by Fis and activated by Crp.

    Science.gov (United States)

    Xu, J; Johnson, R C

    1995-06-01

    Escherichia coli aldB was identified as a gene that is negatively regulated by Fis but positively regulated by RpoS. The complete DNA sequence determined in this study indicates that aldB encodes a 56.3-kDa protein which shares a high degree of homology with an acetaldehyde dehydrogenase encoded by acoD of Alcaligenes eutrophus and an aldehyde dehydrogenase encoded by aldA of Vibrio cholerae and significant homology with a group of other aldehyde dehydrogenases from prokaryotes and eukaryotes. Expression of aldB is maximally induced during the transition from exponential phase to stationary phase. Its message levels are elevated three- to fourfold by a fis mutation and abolished by an rpoS mutation. In addition, the expression of an aldB-lacZ fusion was decreased about 20-fold in the absence of crp. DNase I footprinting analysis showed that five Fis binding sites and one Crp binding site are located within the aldB promoter region, suggesting that Fis and Crp are acting directly to control aldB transcription. AldB expression is induced by ethanol, but in contrast to that of most of the RpoS-dependent genes, the expression of aldB is not altered by an increase in medium osmolarity.

  18. Quality control of the documentation process in electronic economic activities

    Directory of Open Access Journals (Sweden)

    Krutova A.S.

    2017-06-01

    Full Text Available It is proved that the main tool that will provide adequate information resources e economic activities of social and economic relations are documenting quality control processes as the basis of global information space. Directions problems as formation evaluation information resources in the process of documentation, namely development tools assess the efficiency of the system components – qualitative assessment; development of mathematical modeling tools – quantitative evaluation. A qualitative assessment of electronic documentation of economic activity through exercise performance, efficiency of communication; document management efficiency; effectiveness of flow control operations; relationship management effectiveness. The concept of quality control process documents electronically economic activity to components which include: the level of workflow; forms adequacy of information; consumer quality documents; quality attributes; type of income data; condition monitoring systems; organizational level process documentation; attributes of quality, performance quality consumer; type of management system; type of income data; condition monitoring systems. Grounded components of the control system electronic document subjects of economic activity. Detected components IT-audit management system economic activity: compliance audit; audit of internal control; detailed multilevel analysis; corporate risk assessment methodology. The stages and methods of processing electronic transactions economic activity during condition monitoring of electronic economic activity.

  19. 76 FR 9024 - Agency Information Collection Activities; Proposed Collection; Comment Request; Electronic...

    Science.gov (United States)

    2011-02-16

    ...] Agency Information Collection Activities; Proposed Collection; Comment Request; Electronic Records; Electronic Signatures AGENCY: Food and Drug Administration, HHS. ACTION: Notice. SUMMARY: The Food and Drug... relating to FDA's electronic records and electronic signatures. DATES: Submit either electronic or written...

  20. An improved method for the assay of platelet pyruvate dehydrogenase

    International Nuclear Information System (INIS)

    Schofield, P.J.; Griffiths, L.R.; Rogers, S.H.

    1980-01-01

    An improved method for the assay of human platelet pyruvate dehydrogenase is described. By generating the substrate [1- 14 C]pyruvate in situ from [1- 14 C]lactate plus L-lactate dehydrogenase, the rate of spontaneous decarboxylation is dramatically reduced, allowing far greater sensitivity in the assay of low activities of pyruvate dehydrogenase. In addition, no special precautions are required for the storage and use of [1- 14 C]lactate, in contrast to those for [1- 14 C]pyruvate. These factors allow a 5-10-fold increase in sensitivity compared with current methods. The pyruvate dehydrogenase activity of normal subjects as determined by the [1- 14 C]lactate system was 215+-55 pmol min -1 mg -1 protein (n=18). The advantages of this assay system are discussed. (Auth.)

  1. Cloning and mRNA Expression of NADH Dehydrogenase during Ochlerotatus taeniorhynchus Development and Pesticide Response

    Science.gov (United States)

    NADH dehydrogenase, the largest of the respiratory complexes, is the first enzyme of the mitochondrial electron transport chain. We have cloned and sequenced cDNA of NADH dehydrogenase gene from Ochlerotatus (Ochlerotatus) taeniorhynchus (Wiedemann) adult (GeneBank Accession number: FJ458415). The ...

  2. Patient activation and use of an electronic patient portal.

    Science.gov (United States)

    Ancker, Jessica S; Osorio, Snezana N; Cheriff, Adam; Cole, Curtis L; Silver, Michael; Kaushal, Rainu

    2015-01-01

    Electronic patient portals give patients access to personal medical data, potentially creating opportunities to improve knowledge, self-efficacy, and engagement in healthcare. The combination of knowledge, self-efficacy, and engagement has been termed activation. Our objective was to assess the relationship between patient activation and outpatient use of a patient portal. Survey. A telephone survey was conducted with 180 patients who had been given access to a portal, 113 of whom used it and 67 of whom did not. The validated patient activation measure (PAM) was administered along with questions about demographics and behaviors. Portal users were no different from nonusers in patient activation. Portal users did have higher education level and more frequent Internet use, and were more likely to have precisely 2 prescription medications than to have more or fewer. Patients who chose to use an electronic patient portal were not more highly activated than nonusers, although they were more educated and more likely to be Internet users.

  3. Activity coefficients of electrons and holes in semiconductors

    International Nuclear Information System (INIS)

    Orazem, M.E.; Newman, J.

    1984-01-01

    Dilute-solution transport equations with constant activity coefficients are commonly used to model semiconductors. These equations are consistent with a Boltzmann distribution and are invalid in regions where the species concentration is close to the respective site concentration. A more rigorous treatment of transport in a semiconductor requires activity coefficients which are functions of concentration. Expressions are presented for activity coefficients of electrons and holes in semiconductors for which conduction- and valence-band energy levels are given by the respective bandedge energy levels. These activity coefficients are functions of concentration and are thermodynamically consistent. The use of activity coefficients in macroscopic transport relationships allows a description of electron transport in a manner consistent with the Fermi-Dirac distribution

  4. Diversity of organotrophic bacteria, activity of dehydrogenases and urease as well as seed germination and root growth Lepidium sativum, Sorghum saccharatum and Sinapis alba under the influence of polycyclic aromatic hydrocarbons.

    Science.gov (United States)

    Lipińska, Aneta; Wyszkowska, Jadwiga; Kucharski, Jan

    2015-12-01

    Polycyclic aromatic hydrocarbons are organic compounds with highly toxic, carcinogenic, and mutagenic properties, which adversely affect the basic biological parameters of the soil, including the count of microorganisms, and the enzymatic activity. In addition to disturbances to the biological activity of the soil, PAHs may also exhibit toxic effects on plants. In view of the above, the study involved testing aimed at the determination of the effects of polycyclic aromatic hydrocarbons in a form of naphthalene, phenanthrene, anthracene and pyrene on the count, colony development (CD) index, ecophysiological (EP) diversity index of organotrophic bacteria, and the activity of soil dehydrogenases and soil urease. Moreover, an attempt was made to determine the soil's resistance based on the activity of the above-listed enzymes, and the effect of polycyclic aromatic hydrocarbons on seed germination and root growth was assessed by Lepidium sativum, Sorghum saccharatum, and Sinapis alba. In addition, the species of bacteria found in a soil subjected to strong pressure of polycyclic aromatic hydrocarbons were isolated. The experiment was performed in a laboratory on samples of loamy sand. Polycyclic aromatic hydrocarbons were introduced into the soil in an amount of 0, 1000, 2000, and 4000 mg kg(-1) of soil dry matter. Germination and growth of cress (L. sativum), white mustard (S. alba), and sweet sorghum (S. saccharatum) were determined using Phytotoxkit tests. It was found that the tested PAHs increased the average colony counts of organotrophic soil bacteria; pyrene did so to the greatest extent (2.2-fold relative to non-contaminated soil), phenanthrene to the smallest extent (1.4-fold relative to non-contaminated soil). None of the PAHs changed the value of the bacterial colony development (CD) index, while anthracene and pyrene increased the value of the eco-physiological (EP) diversity indicator. PAHs lowered the activity of the tested enzymes. The activity of

  5. Structural characterization of the thermostable Bradyrhizobium japonicumD-sorbitol dehydrogenase.

    Science.gov (United States)

    Fredslund, Folmer; Otten, Harm; Gemperlein, Sabrina; Poulsen, Jens Christian N; Carius, Yvonne; Kohring, Gert Wieland; Lo Leggio, Leila

    2016-11-01

    Bradyrhizobium japonicum sorbitol dehydrogenase is NADH-dependent and is active at elevated temperatures. The best substrate is D-glucitol (a synonym for D-sorbitol), although L-glucitol is also accepted, giving it particular potential in industrial applications. Crystallization led to a hexagonal crystal form, with crystals diffracting to 2.9 Å resolution. In attempts to phase the data, a molecular-replacement solution based upon PDB entry 4nbu (33% identical in sequence to the target) was found. The solution contained one molecule in the asymmetric unit, but a tetramer similar to that found in other short-chain dehydrogenases, including the search model, could be reconstructed by applying crystallographic symmetry operations. The active site contains electron density consistent with D-glucitol and phosphate, but there was not clear evidence for the binding of NADH. In a search for the features that determine the thermostability of the enzyme, the T m for the orthologue from Rhodobacter sphaeroides, for which the structure was already known, was also determined, and this enzyme proved to be considerably less thermostable. A continuous β-sheet is formed between two monomers in the tetramer of the B. japonicum enzyme, a feature not generally shared by short-chain dehydrogenases, and which may contribute to thermostability, as may an increased Pro/Gly ratio.

  6. Electron beam injection during active experiments. I - Electromagnetic wave emissions

    Science.gov (United States)

    Winglee, R. M.; Kellogg, P. J.

    1990-01-01

    The wave emissions produced in Echo 7 experiment by active injections of electron beams were investigated to determine the properties of the electromagnetic and electrostatic fields for both the field-aligned and cross-field injection in such experiments and to evaluate the sources of free energy and relative efficiencies for the generation of the VLF and HF emissions. It is shown that, for typical beam energies in active experiments, electromagnetic effects do not substantially change the bulk properties of the beam, spacecraft charging, and plasma particle acceleration. Through simulations, beam-generated whistlers; fundamental z-mode and harmonic x-mode radiation; and electrostatic electron-cyclotron, upper-hybrid, Langmuir, and lower-hybrid waves were identified. The characteristics of the observed wave spectra were found to be sensitive to both the ratio of the electron plasma frequency to the cyclotron frequency and the angle of injection relative to the magnetic field.

  7. Soft Active Materials for Actuation, Sensing, and Electronics

    OpenAIRE

    Kramer, Rebecca Krone

    2012-01-01

    Future generations of robots, electronics, and assistive medical devices will include systems that are soft and elastically deformable, allowing them to adapt their morphology in unstructured environments. This will require soft active materials for actuation, circuitry, and sensing of deformation and contact pressure. The emerging field of soft robotics utilizes these soft active materials to mimic the inherent compliance of natural soft-bodied systems. As the elasticity of robot components ...

  8. Protecting patients’ electronic health records using enhanced active bundles

    NARCIS (Netherlands)

    Salih, R.M.; Lilien, L.T.; Ben Othmane, L.; Arriaga, R.; Matic, A.

    2012-01-01

    We propose a solution that provides protection for patients' electronic health/medical records disseminated among different authorized healthcare information systems. The solution is known as Active Bundles using a Trusted Third Party (ABTTP). It is based on the use of trusted third parties, and the

  9. Regeneration of used activated carbon by electron beam irradiation

    International Nuclear Information System (INIS)

    Arai, H.; Hosono, M.; Zhu, G.; Miyata, T.

    1992-01-01

    The adsorbing power of granular activated carbons which adsorbed sodium laurylsulfate were most effectively recovered by irradiation of high energy electron beams in nitrogen stream, and the carbon was hardly lost by irradiation. The regeneration was induced mainly by microscopic heating of adsorption sites. Regeneration was also confirmed by adsorption endotherms. Regeneration cost was tentatively evaluated. (author)

  10. Identification of the human mitochondrial FAD transporter and its potential role in multiple acyl-CoA dehydrogenase deficiency

    NARCIS (Netherlands)

    Spaan, András N.; Ijlst, Lodewijk; van Roermund, Carlo W. T.; Wijburg, Frits A.; Wanders, Ronald J. A.; Waterham, Hans R.

    2005-01-01

    Multiple acyl-CoA dehydrogenase deficiency (MADD) or glutaric aciduria type II (GAII) is most often caused by mutations in the genes encoding the alpha- or beta-subunit of electron transfer flavoprotein (ETF) or electron transfer flavoprotein dehydrogenase (ETF-DH). Since not all patients have

  11. Kinetics of soil dehydrogenase in response to exogenous Cd toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Tan, Xiangping [College of Natural Resources and Environment, Northwest A& F University, Yangling, 712100, Shaanxi (China); Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, CAS 723 Xingke Rd., Tianhe District, Guangzhou 510650 (China); Wang, Ziquan; Lu, Guannan [College of Natural Resources and Environment, Northwest A& F University, Yangling, 712100, Shaanxi (China); He, Wenxiang, E-mail: wenxianghe@nwafu.edu.cn [College of Natural Resources and Environment, Northwest A& F University, Yangling, 712100, Shaanxi (China); Key Laboratory of Plant Nutrition and Agro-environment in Northwest China, Ministry of Agriculture, Northwest A& F University, Yangling, 712100, Shaanxi (China); Wei, Gehong [College of Life Sciences, Northwest A& F University, Yangling, 712100, Shaanxi (China); Huang, Feng; Xu, Xinlan; Shen, Weijun [Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, CAS 723 Xingke Rd., Tianhe District, Guangzhou 510650 (China)

    2017-05-05

    Highlights: • pH explained 30–45% of the dehydrogenase activity (DHA), V{sub max}, and K{sub m} variations across soils. • Different inhibition mechanism of Cd to DHA varied soil types. • Soil properties and inhibition constant affect the toxicity of Cd. • Reaction constant (k) could indicate sensitively the toxicity of Cd to DHA. - Abstract: Soil dehydrogenase plays a role in the biological oxidation of soil organic matter and can be considered a good measure of the change of microbial oxidative activity under environmental pollutions. However, the kinetic characteristic of soil dehydrogenase under heavy metal stresses has not been investigated thoroughly. In this study, we characterized the kinetic characteristic of soil dehydrogenase in 14 soil types, and investigated how kinetic parameters changed under spiked with different concentrations of cadmium (Cd). The results showed that the K{sub m} and V{sub max} values of soil dehydrogenase was among 1.4–7.3 mM and 15.9–235.2 μM h{sup −1} in uncontaminated soils, respectively. In latosolic red soil and brown soil, the inhibitory kinetic mechanism of Cd to soil dehydrogenase was anticompetitive inhibition with inhibition constants (K{sub i}) of 12 and 4.7 mM, respectively; in other soils belonged to linear mixed inhibition, the values of K{sub i} were between 0.7–4.2 mM. Soil total organic carbon and K{sub i} were the major factors affecting the toxicity of Cd to dehydrogenase activity. In addition, the velocity constant (k) was more sensitive to Cd contamination compared to V{sub max} and K{sub m}, which was established as an early indicator of gross changes in soil microbial oxidative activity caused by Cd contamination.

  12. 15-year-activity of Electron Linear Accelerator Laboratory

    International Nuclear Information System (INIS)

    Karolczak, S.

    1999-01-01

    The purchase of the Russian Electron Linear Accelerator ELU-6E by Institute of Radiation Technique of Lodz Technical University in 1978 started the activity of the ELA Laboratory. The accelerator itself and many additional scientific equipment designed and built during past 15 years have became the basic investigation tool for the ITR now. The most important measuring systems based on electron beam as irradiation source are: pulse radiolysis system with detection in IR, UV and visible region of the spectra, radiation induced conductometry, Faraday chamber and computerized data acquisition and processing system

  13. The relationship between ionospheric temperature, electron density and solar activity

    International Nuclear Information System (INIS)

    McDonald, J.N.; Williams, P.J.S.

    1980-01-01

    In studying the F-region of the ionosphere several authors have concluded that the difference between the electron temperature Tsub(e) and the ion temperature Tsub(i) is related to the electron density N. It was later noted that solar activity (S) was involved and an empirical relationship of the following form was established: Tsub(e)-Tsub(i) = A-BN+CS. The present paper extends this work using day-time data over a four year period. The results are given and discussed. A modified form of the empirical relation is proposed. (U.K.)

  14. Purification of 2-oxo acid dehydrogenase multienzyme complexes from ox heart by a new method.

    OpenAIRE

    Stanley, C J; Perham, R N

    1980-01-01

    A new method is described that allows the parallel purification of the pyruvate dehydrogenase and 2-oxoglutarate dehydrogenase multienzyme complexes from ox heart without the need for prior isolation of mitochondria. All the assayable activity of the 2-oxo acid dehydrogenase complexes in the disrupted tissue is made soluble by the inclusion of non-ionic detergents such as Triton X-100 or Tween-80 in the buffer used for the initial extraction of the enzyme complexes. The yields of the pyruvate...

  15. Coulometric bioelectrocatalytic reactions based on NAD-dependent dehydrogenases in tricarboxylic acid cycle

    International Nuclear Information System (INIS)

    Fukuda, Jun; Tsujimura, Seiya; Kano, Kenji

    2008-01-01

    This paper describes the characterization of mediated electro-enzymatic electrolysis systems based on NAD-dependent dehydrogenase reactions in the tricarboxylic acid (TCA) cycle. A micro-bulk electrolysis system with a carbon felt anode immersed in an electrolysis solution with a value of about 10 μL was constructed for coulometric analysis of the substrate oxidation. Diaphorase (DI) was used to couple the NAD-dependent dehydrogenase reaction with the anode reaction of a suitable redox mediator. We focused on three types of NAD-dependant dehydrogenases reactions in this research: (1) isocitrate oxidation, in which the standard Gibbs energy change (ΔG o ') is negative; (2) α-ketoglutarate oxidation, which involves an electrochemically active coenzyme A (CoA); and (3) malate oxidation, which is thermodynamically unfavorable because of a large positive ΔG o ' value. The complete electrolysis of isocitrate was easily achieved, supporting the effective re-oxidation of NADH in the diaphorase-catalyzed electrochemical reaction. CoA was unfavorably oxidized at the electrodes in the presence of some mediators. The electrocatalytic oxidation of CoA was suppressed and the quantitative electrochemical oxidation of α-ketoglutarate was achieved by selecting a suitable mediator with negligibly slow electron transfer kinetics with CoA. The uphill malate oxidation was susceptible to product inhibition in the bioelectrochemical system, although NADH generated in the malate dehydrogenase reaction was immediately oxidized in the electrochemical system. The inhibition was successfully suppressed by linking citrate synthase to quench oxaloacetate and to make the total ΔG o ' value negative

  16. Coulometric bioelectrocatalytic reactions based on NAD-dependent dehydrogenases in tricarboxylic acid cycle

    Energy Technology Data Exchange (ETDEWEB)

    Fukuda, Jun [Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan); Tsujimura, Seiya [Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan)], E-mail: seiya@kais.kyoto-u.ac.jp; Kano, Kenji [Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Sakyo-ku, Kyoto 606-8502 (Japan)], E-mail: kkano@kais.kyoto-u.ac.jp

    2008-12-30

    This paper describes the characterization of mediated electro-enzymatic electrolysis systems based on NAD-dependent dehydrogenase reactions in the tricarboxylic acid (TCA) cycle. A micro-bulk electrolysis system with a carbon felt anode immersed in an electrolysis solution with a value of about 10 {mu}L was constructed for coulometric analysis of the substrate oxidation. Diaphorase (DI) was used to couple the NAD-dependent dehydrogenase reaction with the anode reaction of a suitable redox mediator. We focused on three types of NAD-dependant dehydrogenases reactions in this research: (1) isocitrate oxidation, in which the standard Gibbs energy change ({delta}G{sup o}') is negative; (2) {alpha}-ketoglutarate oxidation, which involves an electrochemically active coenzyme A (CoA); and (3) malate oxidation, which is thermodynamically unfavorable because of a large positive {delta}G{sup o}' value. The complete electrolysis of isocitrate was easily achieved, supporting the effective re-oxidation of NADH in the diaphorase-catalyzed electrochemical reaction. CoA was unfavorably oxidized at the electrodes in the presence of some mediators. The electrocatalytic oxidation of CoA was suppressed and the quantitative electrochemical oxidation of {alpha}-ketoglutarate was achieved by selecting a suitable mediator with negligibly slow electron transfer kinetics with CoA. The uphill malate oxidation was susceptible to product inhibition in the bioelectrochemical system, although NADH generated in the malate dehydrogenase reaction was immediately oxidized in the electrochemical system. The inhibition was successfully suppressed by linking citrate synthase to quench oxaloacetate and to make the total {delta}G{sup o}' value negative.

  17. Polarized electrons and the origin of optical activity

    International Nuclear Information System (INIS)

    Bonner, W.A.; Dort, M.A. Van; Yearian, M.R.; Zeman, H.D.; Li, G.C.; Stanford Univ., Calif.

    1976-01-01

    The history of experiments bearing on the origin of optical acitivity in nature by parity non-conservation during the β-decay of radioactive isotopes is briefly reviewed. Following this, we present a more detailed description of our recent published and unpublished data and calculations regarding the generation of optical activity in DL-leucine by means of artificially produced longitudinally polarized electrons from a linear accelerator

  18. Multi-organ abnormalities and mTORC1 activation in zebrafish model of multiple acyl-CoA dehydrogenase deficiency.

    Directory of Open Access Journals (Sweden)

    Seok-Hyung Kim

    2013-06-01

    Full Text Available Multiple Acyl-CoA Dehydrogenase Deficiency (MADD is a severe mitochondrial disorder featuring multi-organ dysfunction. Mutations in either the ETFA, ETFB, and ETFDH genes can cause MADD but very little is known about disease specific mechanisms due to a paucity of animal models. We report a novel zebrafish mutant dark xavier (dxa(vu463 that has an inactivating mutation in the etfa gene. dxa(vu463 recapitulates numerous pathological and biochemical features seen in patients with MADD including brain, liver, and kidney disease. Similar to children with MADD, homozygote mutant dxa(vu463 zebrafish have a spectrum of phenotypes ranging from moderate to severe. Interestingly, excessive maternal feeding significantly exacerbated the phenotype. Homozygous mutant dxa(vu463 zebrafish have swollen and hyperplastic neural progenitor cells, hepatocytes and kidney tubule cells as well as elevations in triacylglycerol, cerebroside sulfate and cholesterol levels. Their mitochondria were also greatly enlarged, lacked normal cristae, and were dysfunctional. We also found increased signaling of the mechanistic target of rapamycin complex 1 (mTORC1 with enlarged cell size and proliferation. Treatment with rapamycin partially reversed these abnormalities. Our results indicate that etfa gene function is remarkably conserved in zebrafish as compared to humans with highly similar pathological, biochemical abnormalities to those reported in children with MADD. Altered mTORC1 signaling and maternal nutritional status may play critical roles in MADD disease progression and suggest novel treatment approaches that may ameliorate disease severity.

  19. Comparing the impact of melatonin and captopril on early effects of radiation on the heart tissue by studying glutathione, malondialdehyde, and lactate dehydrogenase enzyme activity in rats

    International Nuclear Information System (INIS)

    Shirazi, Alireza; Tabatabaie, Farnaz; Ghazi-Khansari, Mahmoud; Mirzaei, Hamidreza

    2015-01-01

    Prevention of secondary malignancy while the patient is receiving radiotherapy for the management of primary cancer has been an enormous challenge for biological and medical safety. The aim of the study is to compare protective effects of melatonin and captopril on early effects of radiation on the heart tissue of rats. Forty-eight adult male Wistar rats weighing 180-220 g were used. The rats were divided into six groups and the rats were exposed to 8 Gy whole body dose from Cobalt-60 sources. Thirty minutes prior to irradiation, six animals received melatonin (100 mg/kg body weight), and six animals received captopril (50 mg/kg body weight). All groups were sacrificed 10 days post-irradiation, and hearts were collected. Malondialdehyde (MDA), lactate dehydrogenase (LDH), and glutathione (GSH) were measured to evaluate cellular oxidative stress-induced injury. The biochemical data are presented as mean ± standard error of the mean, and the difference between the groups was analyzed using a two-way variance analysis. Treatment with captopril resulted in a significant increase in LDH and MDA, although the level of GSH was decreased (P < 0.01). MDA and LDH levels were decreased after melatonin treatment while GSH level was increased (P < 0.001). Melatonin has protective effects following radiation, while treatment with captopril post-irradiation seems to be radiosensitizing and does not have protective effects against radiation exposure. (author)

  20. Artemisinin inhibits chloroplast electron transport activity: mode of action.

    Directory of Open Access Journals (Sweden)

    Adyasha Bharati

    Full Text Available Artemisinin, a secondary metabolite produced in Artemisia plant species, besides having antimalarial properties is also phytotoxic. Although, the phytotoxic activity of the compound has been long recognized, no information is available on the mechanism of action of the compound on photosynthetic activity of the plant. In this report, we have evaluated the effect of artemisinin on photoelectron transport activity of chloroplast thylakoid membrane. The inhibitory effect of the compound, under in vitro condition, was pronounced in loosely and fully coupled thylakoids; being strong in the former. The extent of inhibition was drastically reduced in the presence of uncouplers like ammonium chloride or gramicidin; a characteristic feature described for energy transfer inhibitors. The compound, on the other hand, when applied to plants (in vivo, behaved as a potent inhibitor of photosynthetic electron transport. The major site of its action was identified to be the Q(B; the secondary quinone moiety of photosystemII complex. Analysis of photoreduction kinetics of para-benzoquinone and duroquinone suggest that the inhibition leads to formation of low pool of plastoquinol, which becomes limiting for electron flow through photosystemI. Further it was ascertained that the in vivo inhibitory effect appeared as a consequence of the formation of an unidentified artemisinin-metabolite rather than by the interaction of the compound per se. The putative metabolite of artemisinin is highly reactive in instituting the inhibition of photosynthetic electron flow eventually reducing the plant growth.

  1. Genetics Home Reference: dihydropyrimidine dehydrogenase deficiency

    Science.gov (United States)

    ... 5-fluorouracil and capecitabine. These drugs are not broken down efficiently by people with dihydropyrimidine dehydrogenase deficiency ... of this enzyme. Because fluoropyrimidine drugs are also broken down by the dihydropyrimidine dehydrogenase enzyme, deficiency of ...

  2. Active pixel sensor array as a detector for electron microscopy.

    Science.gov (United States)

    Milazzo, Anna-Clare; Leblanc, Philippe; Duttweiler, Fred; Jin, Liang; Bouwer, James C; Peltier, Steve; Ellisman, Mark; Bieser, Fred; Matis, Howard S; Wieman, Howard; Denes, Peter; Kleinfelder, Stuart; Xuong, Nguyen-Huu

    2005-09-01

    A new high-resolution recording device for transmission electron microscopy (TEM) is urgently needed. Neither film nor CCD cameras are systems that allow for efficient 3-D high-resolution particle reconstruction. We tested an active pixel sensor (APS) array as a replacement device at 200, 300, and 400 keV using a JEOL JEM-2000 FX II and a JEM-4000 EX electron microscope. For this experiment, we used an APS prototype with an area of 64 x 64 pixels of 20 microm x 20 microm pixel pitch. Single-electron events were measured by using very low beam intensity. The histogram of the incident electron energy deposited in the sensor shows a Landau distribution at low energies, as well as unexpected events at higher absorbed energies. After careful study, we concluded that backscattering in the silicon substrate and re-entering the sensitive epitaxial layer a second time with much lower speed caused the unexpected events. Exhaustive simulation experiments confirmed the existence of these back-scattered electrons. For the APS to be usable, the back-scattered electron events must be eliminated, perhaps by thinning the substrate to less than 30 microm. By using experimental data taken with an APS chip with a standard silicon substrate (300 microm) and adjusting the results to take into account the effect of a thinned silicon substrate (30 microm), we found an estimate of the signal-to-noise ratio for a back-thinned detector in the energy range of 200-400 keV was about 10:1 and an estimate for the spatial resolution was about 10 microm.

  3. Cellular distribution, purification and electrophoretic properties of malate dehydrogenase in Trichuris ovis and inhibition by benzimidazoles and pyrimidine derivatives.

    Science.gov (United States)

    Sanchez-Moreno, M; Ortega, J E; Valero, A

    1989-12-01

    High levels of malate dehydrogenase were found in Trichuris ovis. Two molecular forms of the enzyme, of different cellular location and electrophoretic pattern, were isolated and purified. The activity of soluble malate dehydrogenase was greater than that of mitochondrial malate dehydrogenase. Both forms also displayed different electrophoretic profiles in comparison with purified extracts from goat (Capra hircus) liver. Substrate concentration directly affected enzyme activity. Host and parasite malate dehydrogenase activity were both inhibited by a series of benzimidazoles and pyrimidine-derived compounds, some of which markedly reduced parasite enzyme activity, but not host enzyme activity. Percentage inhibition by some pyrimidine derivatives was greater than that produced by benzimidazoles.

  4. Determination of estradiol, estrone and progesterone in serum and human endometrium in correlation to the content of steroid receptors and 17β-hydroxysteroid dehydrogenase activity during menstrual cycle

    International Nuclear Information System (INIS)

    Schmidt-Gollwitzer, M.; Eiletz, J.; Pachaly, J.

    1977-01-01

    A study has been carried out to compare the influence of estradiol estrone and progesterone on the estradiol and progesterone receptor levels and 17β-hydroxysteroid dehydrogenase (17β-HSD) activity in human endometrium. The steroid hormone concentrations were measured simultaneously in both serum and endometrial tissue. The estradiol receptor levels were highest during the early proliferative phase and were inversely correlated to the endometrial tissue and serum concentrations of estradiol and progesterone. The highest progesterone binding capacity was found in endometrical cytosol during the late proliferative phase (midcycle) of the menstrual cycle. The midcycle peak of the progesterone receptor level correlated well with the first peak of the serum and tissue concentrations of estradiol. During,the luteal phase, in contrast to the proliferative phase, the progesterone receptor level decreased whereas serum progesterone concentrations were high. Estrone concentrations were higher in secretory than proliferative endometrium and were correlated to the increase of progesterone receptor content and 17β-HSD activity during early secretory phase. The 17β-HSD activity was approximately 10-fold higher during the early secretory than during the proliferative phase. The progesterone receptor level was highly correlated to the specific 17β-HSD activity of the microsomal fraction whereas a significant inverse correlation between the enzyme activity and the estradiol receptor level was observed. (orig.) [de

  5. Active silicon x-ray for measuring electron temperature

    International Nuclear Information System (INIS)

    Snider, R.T.

    1994-07-01

    Silicon diodes are commonly used for x-ray measurements in the soft x-ray region between a few hundred ev and 20 keV. Recent work by Cho has shown that the charge collecting region in an underbiased silicon detector is the depletion depth plus some contribution from a region near the depleted region due to charge-diffusion. The depletion depth can be fully characterized as a function of the applied bias voltage and is roughly proportional to the squart root of the bias voltage. We propose a technique to exploit this effect to use the silicon within the detector as an actively controlled x-ray filter. With reasonable silicon manufacturing methods, a silicon diode detector can be constructed in which the sensitivity of the collected charge to the impinging photon energy spectrum can be changed dynamically in the visible to above the 20 keV range. This type of detector could be used to measure the electron temperature in, for example, a tokamak plasma by sweeping the applied bias voltage during a plasma discharge. The detector samples different parts of the energy spectrum during the bias sweep, and the data collected contains enough information to determine the electron temperature. Benefits and limitations of this technique will be discussed along with comparisons to similar methods for measuring electron temperature and other applications of an active silicon x-ray filter

  6. Relationship between electronic structure and radioprotective activity of some indazoles

    International Nuclear Information System (INIS)

    Sokolov, Yu.A.

    2000-01-01

    The quantum-chemical study of electronic structure of 29 indasoles with complete optimization of geometry and search of quantitative link between the established characteristics and radioprotective activity (RPA) was carried out through the MNDO method with application of multiple linear and nonlinear regression analysis and the basic component method. The equations of correlation relationship between the RPA and electronic characteristics are presented. 10 indasole structures, the forecasted RPA values whereof (survival rate, %) equal 50% and above, are selected. The statistic significance of the obtained correlation equations and their regression coefficients make it possible to conclude, that the established relationships are not accidental and are prospective for forecasting RPA of other close compounds of the indasole series [ru

  7. Measurement of the activity of electron capturing isotopes

    International Nuclear Information System (INIS)

    Szoerenyi, A.

    1980-01-01

    In order to measure precisely the activity of electron capturing isotopes, an equipment was constructed for the detection the X-photons, the Auger- and the conversing electrons by a high-pressure, gas-flow 4π proportional counter. The proportional counter and the NaI(Tl) scintillation counter are placed in a common lead-shielding, thus, the equipment is suited for the measurement of radioisotopes decaying in coincidence. The structure of the proportional counter and of the pressure-control system are detailed. As an example, the energy spectra of a 109 Cd solution, taken at different pressures, are published. At a pressure of 1.1 MPa the 3 peaks are well separated. The results of an international test, in which the radioactivity of a 57 Co sample was determined, are published, too. (L.E.)

  8. Identification, Cloning, and Characterization of l-Phenylserine Dehydrogenase from Pseudomonas syringae NK-15

    Directory of Open Access Journals (Sweden)

    Sakuko Ueshima

    2010-01-01

    Full Text Available The gene encoding d-phenylserine dehydrogenase from Pseudomonas syringae NK-15 was identified, and a 9,246-bp nucleotide sequence containing the gene was sequenced. Six ORFs were confirmed in the sequenced region, four of which were predicted to form an operon. A homology search of each ORF predicted that orf3 encoded l-phenylserine dehydrogenase. Hence, orf3 was cloned and overexpressed in Escherichia coli cells and recombinant ORF3 was purified to homogeneity and characterized. The purified ORF3 enzyme showed l-phenylserine dehydrogenase activity. The enzymological properties and primary structure of l-phenylserine dehydrogenase (ORF3 were quite different from those of d-phenylserine dehydrogenase previously reported. l-Phenylserine dehydrogenase catalyzed the NAD+-dependent oxidation of the β-hydroxyl group of l-β-phenylserine. l-Phenylserine and l-threo-(2-thienylserine were good substrates for l-phenylserine dehydrogenase. The genes encoding l-phenylserine dehydrogenase and d-phenylserine dehydrogenase, which is induced by phenylserine, are located in a single operon. The reaction products of both enzymatic reactions were 2-aminoacetophenone and CO2.

  9. RESEARCH ON THE INFLUENCE OF H+ IONS CONCENTRATION ON THE DYNAMICS OF THE ACTIVITIES OF CERTAIN DEHYDROGENASES OF THE KREBS CYCLE IN THE MONILINIA LAXA (ADERH. & RUHL. HONEY FUNGUS PARASITIC ON PLUM TREES

    Directory of Open Access Journals (Sweden)

    Tutu Elena

    2010-09-01

    Full Text Available During the process of nutrition, thus in that of their growth, microorganisms are subject to the influences of certain environmental factors that condition the microbial activity determining either the growth and reproduction, or the inhibition of activity and the inactivation of microorganisms. A well known means of expressing the H+ ions concentration in a certain environment is the pH, an important chemical factor that is closely observed when growing ascomycetes, for any alteration of its value entails conformational alterations of their enzymes, the characteristics of the substrate, such that they can no longer interact with the active site of the enzyme or be subject to catalysis. The present study comprises the results of our research on certain oxidoreductase implied in the steps of the Krebs cycle in the Monilinia laxa (Aderh.&Ruhl. Honey, a fungus that parasites the prune. The enzymatic determinations took place at 7 and 14 days from the mycelium of the fungus cultivated in Leonian media, whose pH was adjusted to values between 2.0 and 9.0 by using NaOH 1N and HCl 0,1N solutions. We registered different values of the dehydrogenasic activity, directly correlated with the physiological condition of the fungus (given its age and with the initial pH value of the culture’s environment.

  10. RESEARCH ON THE INFLUENCE OF H+ IONS CONCENTRATION ON THE DYNAMICS OF THE ACTIVITIES OF CERTAIN DEHYDROGENASES OF THE KREBS CYCLE IN THE MONILINIA LAXA (ADERH. & RUHL. HONEY FUNGUS PARASITIC ON PLUM TREES

    Directory of Open Access Journals (Sweden)

    Elena Tutu

    2011-11-01

    Full Text Available During the process of nutrition, thus in that of their growth, microorganisms are subject to the influences of certain environmental factors that condition the microbial activity determining either the growth and reproduction, or the inhibition of activity and the inactivation of microorganisms. A well known means of expressing the H+ ions concentration in a certain environment is the pH, an important chemical factor that is closely observed when growing ascomycetes, for any alteration of its value entails conformational alterations of their enzymes, the characteristics of the substrate, such that they can no longer interact with the active site of the enzyme or be subject to catalysis. The present study comprises the results of our research on certain oxidoreductase implied in the steps of the Krebs cycle in the Monilinia laxa (Aderh.&Ruhl. Honey, a fungus that parasites the prune. The enzymatic determinations took place at 7 and 14 days from the mycelium of the fungus cultivated in Leonian media, whose pH was adjusted to values between 2.0 and 9.0 by using NaOH 1N and HCl 0,1N solutions. We registered different values of the dehydrogenasic activity, directly correlated with the physiological condition of the fungus (given its age and with the initial pH value of the culture’s environment.

  11. Use of a simplified spectrophotometric method for quantitative determination of glucose-6-phosphate dehydrogenase activity in normal children from two day-care centers of the city of São Paulo

    Directory of Open Access Journals (Sweden)

    Roberto Muller

    2003-06-01

    Full Text Available Objective: To evaluate the applicability of a simplified method forquantitative determination of glucose-6-phosphate dehydrogenaseactivity in normal children; to determine the mean, standarddeviation and threshold value under which the enzyme activity isconsidered deficient. Methods: Blood samples were collected from201 children from two day-care centers in the city of São Paulo.The subjects were considered normal based on physicalexamination and laboratory tests. The enzyme activity wasdetermined in red blood cells of normal children using the “TestCombination G-6-PDH®” kit. The following statistical analyses werecarried out: the results were submitted to Student’s t test,Kolmogorov-Smirnov test, lower confidence interval (one-tailedtest and Spearman’s correlation coefficient. Results: The meanhemoglobin value for girls was slightly higher than the mean valuefor boys, but this difference was not statistically significant. Therewas no statistical difference in mean enzyme activities for Caucasianand non-Caucasian children. There was no significant correlation amongenzyme activity levels, red blood cells, hemoglobin levels,hematocrit, reticulocytes, white blood cells and age of patients.The mean enzyme activity for boys was 4.448 U/g Hb, standarddeviation = 1.380 U/g Hb. For girls, the mean enzyme activity was4.531 U/g Hb, standard deviation = 1.386 U/g Hb, and the differencewas not statistically significant. Therefore, the two populationgroups were considered as one single population, presenting amean enzyme activity of 4.490 U/g Hb, standard deviation = 1.380 U/g Hb.Since the distribution curve of enzyme activity values was normal,a lower confidence interval was determined (one-tailed test, witha cutoff point of 2.227 U/g Hb. Conclusion: The method used bySolem proved to be simple, fast, very accurate and useful to detectglucose-6-phosphate dehydrogenase activity and to identifychildren with enzyme deficiency.

  12. Protective immune responses against Schistosoma mansoni infection by immunization with functionally active gut-derived cysteine peptidases alone and in combination with glyceraldehyde 3-phosphate dehydrogenase.

    Directory of Open Access Journals (Sweden)

    Hatem Tallima

    2017-03-01

    Full Text Available Schistosomiasis, a severe disease caused by parasites of the genus Schistosoma, is prevalent in 74 countries, affecting more than 250 million people, particularly children. We have previously shown that the Schistosoma mansoni gut-derived cysteine peptidase, cathepsin B1 (SmCB1, administered without adjuvant, elicits protection (>60% against challenge infection of S. mansoni or S. haematobium in outbred, CD-1 mice. Here we compare the immunogenicity and protective potential of another gut-derived cysteine peptidase, S. mansoni cathepsin L3 (SmCL3, alone, and in combination with SmCB1. We also examined whether protective responses could be boosted by including a third non-peptidase schistosome secreted molecule, glyceraldehyde 3-phosphate dehydrogenase (SG3PDH, with the two peptidases.While adjuvant-free SmCB1 and SmCL3 induced type 2 polarized responses in CD-1 outbred mice those elicited by SmCL3 were far weaker than those induced by SmCB1. Nevertheless, both cysteine peptidases evoked highly significant (P < 0.005 reduction in challenge worm burden (54-65% as well as worm egg counts and viability. A combination of SmCL3 and SmCB1 did not induce significantly stronger immune responses or higher protection than that achieved using each peptidase alone. However, when the two peptidases were combined with SG3PDH the levels of protection against challenge S. mansoni infection reached 70-76% and were accompanied by highly significant (P < 0.005 decreases in worm egg counts and viability. Similarly, high levels of protection were achieved in hamsters immunized with the cysteine peptidase/SG3PDH-based vaccine.Gut-derived cysteine peptidases are highly protective against schistosome challenge infection when administered subcutaneously without adjuvant to outbred CD-1 mice and hamsters, and can also act to enhance the efficacy of other schistosome antigens, such as SG3PDH. This cysteine peptidase-based vaccine should now be advanced to experiments in

  13. The Role of Pyruvate Dehydrogenase Kinase in Diabetes and Obesity

    Directory of Open Access Journals (Sweden)

    In-Kyu Lee

    2014-06-01

    Full Text Available The pyruvate dehydrogenase complex (PDC is an emerging target for the treatment of metabolic syndrome. To maintain a steady-state concentration of adenosine triphosphate during the feed-fast cycle, cells require efficient utilization of fatty acid and glucose, which is controlled by the PDC. The PDC converts pyruvate, coenzyme A (CoA, and oxidized nicotinamide adenine dinucleotide (NAD+ into acetyl-CoA, reduced form of nicotinamide adenine dinucleotide (NADH, and carbon dioxide. The activity of the PDC is up- and down-regulated by pyruvate dehydrogenase kinase and pyruvate dehydrogenase phosphatase, respectively. In addition, pyruvate is a key intermediate of glucose oxidation and an important precursor for the synthesis of glucose, glycerol, fatty acids, and nonessential amino acids.

  14. Effects of Gram-negative Bacteria, E.coli and Cold Exposure on Free Radicals Production, Lactate Dehydrogenase and Glutathione Peroxidase Activity in the Lungs of Rats, Rattus norvigicus

    International Nuclear Information System (INIS)

    AlSaid, A Haffor

    2007-01-01

    The purpose of this study was to explore the effects of LPS-gram negative bacteria and low ambient temperature on free radicals (FR) production, the activities of lactate dehydrogenase (LDH) and glutathione peroxidase (GPx) in the lungs of rats, Rattus norvigisu. Twenty four male rats, matched with age and weigh, were divided randomly into four groups namely control (C), Bacteria (B), cold temperature (T), and bacteria plus cold (BT). The T group was exposed to 10-12degree C ambient temperature for 3 days. Animals of the BT was injected LPS bacteria (IP, 500 micron g/kg) during the last five hour of cold exposure to 10-12 degree C for 3 days. In comparison with C group FR increased significantly (p<0.05) in the experimental groups, indicating high rate of reactive oxygen species (ROS) accumulation. The activity of LDH increased significantly (p<0.05) in the T and BT groups, which demonstrated that bacteria and exposure to cold are causes for cellular injury in the lungs. The synergetic effect of both bacteria and cold on LDH was more intense, as compared with the single effect. The activity of GPx increased significantly (p<0.05) in the B and BT, as compared with the C group. The results of the present study is the first worldwide report to demonstrate that both cold exposure and bacteria infection are mediated by elevation in FR generation. (author)

  15. Soft Active Materials for Actuation, Sensing, and Electronics

    Science.gov (United States)

    Kramer, Rebecca Krone

    Future generations of robots, electronics, and assistive medical devices will include systems that are soft and elastically deformable, allowing them to adapt their morphology in unstructured environments. This will require soft active materials for actuation, circuitry, and sensing of deformation and contact pressure. The emerging field of soft robotics utilizes these soft active materials to mimic the inherent compliance of natural soft-bodied systems. As the elasticity of robot components increases, the challenges for functionality revert to basic questions of fabrication, materials, and design - whereas such aspects are far more developed for traditional rigid-bodied systems. This thesis will highlight preliminary materials and designs that address the need for soft actuators and sensors, as well as emerging fabrication techniques for manufacturing stretchable circuits and devices based on liquid-embedded elastomers.

  16. A polymorphic variant in the human electron transfer flavoprotein alpha-chain (alpha-T171) displays decreased thermal stability and is overrepresented in very-long-chain acyl-CoA dehydrogenase-deficient patients with mild childhood presentation

    DEFF Research Database (Denmark)

    Bross, P; Pedersen, P; Nyholm, M

    1999-01-01

    The consequences of two amino acid polymorphisms of human electron transfer flavoprotein (alpha-T/I171 in the alpha-subunit and beta-M/T154 in the beta-subunit) on the thermal stability of the enzyme are described. The alpha-T171 variant displayed a significantly decreased thermal stability, wher....... This is compatible with a negative modulating effect of the less-stable alpha-T171 ETF variant in this group of VLCAD patients that harbor missense mutations in at least one allele and therefore potentially display residual levels of VLCAD enzyme activity. Udgivelsesdato: 1999-Jun...

  17. Purification and characterization of xylitol dehydrogenase from Fusarium oxysporum

    DEFF Research Database (Denmark)

    Panagiotou, Gianni; Kekos, D.; Macris, B.J.

    2002-01-01

    An NAD(+)-dependent xylitol dehydrogenase (XDH) from Fusarium oxysporum, a key enzyme in the conversion of xylose to ethanol, was purified to homogeneity and characterised. It was homodimeric with a subunit of M-r 48 000, and pI 3.6. It was optimally active at 45degreesC and pH 9-10. It was fully...

  18. Assay of partially purified glutamate dehydrogenase isolated from ...

    African Journals Online (AJOL)

    Glutamate dehydrogenase (E C 1.4.1.1) isolated from the seeds of asparagus beans was partially purified to a factor of 22 by dialysis after fractional precipitation with solid ammonium sulphate at 40 and 60% saturation. A specific activity of 11.78μmol min-1 mg-1 protein was calculated for the partially purified enzyme when ...

  19. Novel guanidine-based inhibitors of inosine monophosphate dehydrogenase.

    Science.gov (United States)

    Iwanowicz, Edwin J; Watterson, Scott H; Liu, Chunjian; Gu, Henry H; Mitt, Toomas; Leftheris, Katerina; Barrish, Joel C; Fleener, Catherine A; Rouleau, Katherine; Sherbina, N Z; Hollenbaugh, Diane L

    2002-10-21

    A series of novel guanidine-based small molecule inhibitors of inosine monophosphate dehydrogenase (IMPDH) was explored. IMPDH catalyzes the rate determining step in guanine nucleotide biosynthesis and is a target for anticancer, immunosuppressive and antiviral therapy. The synthesis and the structure-activity relationships (SARs), derived from in vitro studies, for this new series of inhibitors is given.

  20. Communication between Thiamin Cofactors in the Escherichia coli Pyruvate Dehydrogenase Complex E1 Component Active Centers EVIDENCE FOR A DIRECT PATHWAY BETWEEN THE 4′-AMINOPYRIMIDINE N1′ ATOMS

    Energy Technology Data Exchange (ETDEWEB)

    Nemeria, Natalia S; Arjunan, Palaniappa; Chandrasekhar, Krishnamoorthy; Mossad, Madouna; Tittmann, Kai; Furey, William; Jordan, Frank [Pitt; (Goettingen); (VA); (Rutgers)

    2010-11-03

    Kinetic, spectroscopic, and structural analysis tested the hypothesis that a chain of residues connecting the 4{prime}-aminopyrimidine N1{prime} atoms of thiamin diphosphates (ThDPs) in the two active centers of the Escherichia coli pyruvate dehydrogenase complex E1 component provides a signal transduction pathway. Substitution of the three acidic residues (Glu{sup 571}, Glu{sup 235}, and Glu{sup 237}) and Arg{sup 606} resulted in impaired binding of the second ThDP, once the first active center was filled, suggesting a pathway for communication between the two ThDPs. (1) Steady-state kinetic and fluorescence quenching studies revealed that upon E571A, E235A, E237A, and R606A substitutions, ThDP binding in the second active center was affected. (2) Analysis of the kinetics of thiazolium C2 hydrogen/deuterium exchange of enzyme-bound ThDP suggests half-of-the-sites reactivity for the E1 component, with fast (activated site) and slow exchanging sites (dormant site). The E235A and E571A variants gave no evidence for the slow exchanging site, indicating that only one of two active sites is filled with ThDP. (3) Titration of the E235A and E237A variants with methyl acetylphosphonate monitored by circular dichroism suggested that only half of the active sites were filled with a covalent predecarboxylation intermediate analog. (4) Crystal structures of E235A and E571A in complex with ThDP revealed the structural basis for the spectroscopic and kinetic observations and showed that either substitution affects cofactor binding, despite the fact that Glu{sup 235} makes no direct contact with the cofactor. The role of the conserved Glu{sup 571} residue in both catalysis and cofactor orientation is revealed by the combined results for the first time.

  1. Combined Effect of L-Cysteine and Vitamin E Injected Pre-Irradiation on Glucose-6-Phosphate Dehydrogenase Activity and Certain products of Glycolysis in Blood of Female Rats

    International Nuclear Information System (INIS)

    Abdel-Fattah, K.I.; Abou-Safi, H.M.; Kafafy, Y.A.; Ashry, O.M.

    1999-01-01

    The present work aims to evaluate the protective limits of L-cysteine and vitamin E combination against deleterious effects of gamma radiation on glucose-6-phosphate dehydrogenase activity, liver glycogen, blood glucose, pyruvic and lactic acids and their correlations in adult female rats. Mature female white rats were divided into four groups: 1- Control group. 2- Whole body gamma irradiated group at a dose level two Gy. 3-Group injected with 120 mg/100 g b.wt. L-cysteine+10 mg/100 g b.wt. vitamin E. 4- Group injected with cysteine+ vitamin E one hour before irradiation at 2 Gy dose level. Results revealed that combined administration of cysteine and vitamin E before gamma-irradiation have accelerated the radiation injury on liver glycogen, plasma glucose and G 6 Pd activity, while they showed a protective effect on lactic and pyruvic acids. This could be due to different mechanisms or a biphasic mechanism related to hormonal (like E 2 , T 3 and insulin), enzymatic or metabolic (e.g. oxidation/reduction, catabolic, anabolic factors) control

  2. Dietary modulation of erythrocyte insulin receptor interaction and the regulation of adipose tissue pyruvate dehydrogenase enzyme activity in growing rats; a mechanism of action of dietary fiber in metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Ogunwole, J.O.A.

    1984-01-01

    The metabolic effects of graded cellulose (a dietary fiber) intake were studied at minimal (10%) and maximal (20%) protein levels in male weanling Sprague Dawley rats. The hypothesis was tested that the hypoglycemic effect of high fiber diets is partly mediated through increased tissue sensitivity to insulin at the cell receptor level. Erythrocyte insulin receptor interaction (IRI) and percent insulin stimulation of adipose tissue pyruvate dehydrogenase (PDH) activity (PDS) were used as indices of tissue sensitivity to insulin. IRI was determined by a standardized radioceptor assay PDS by the rate of oxidation of 1-/sup 14/C-pyruvate to /sup 14/CO/sub 2/ in epidymal fat pads and serum insulin levels by radioimmunoassay. In both protein groups, the addition of fiber in the diet resulted in a significant (P < 0.05) increase in food intake (FI) for calorie compensation. Fiber and protein intake had a significant (P < 0.01) effect on IRI and both basal (PDB) and PDS activities of PDH. At all fiber levels, specific percent /sup 125/I-insulin binding (SIB) was higher in the 20% protein groups while in the fiber-free group, a higher SIB was observed in the 10% protein group.

  3. Study on regeneration of activated carbon by means of electron radiation

    International Nuclear Information System (INIS)

    Zhu Guanghua; Arai, H.; Hosono, M.

    1991-01-01

    The results of regeneration of activated carbon adsorbing sodium lauryl sulfate (SLS) by 2 MeV electron radiation, and the dependence of the regeneration rate of activated carbon on the electron current intensity, the temperature of sample and the atmosphere were reported. It is shown that regeneration of activated carbon by electron radiation is full of promise

  4. Modelling of electron transport and of sawtooth activity in tokamaks

    International Nuclear Information System (INIS)

    Angioni, C.

    2001-10-01

    Transport phenomena in tokamak plasmas strongly limit the particle and energy confinement and represent a crucial obstacle to controlled thermonuclear fusion. Within the vast framework of transport studies, three topics have been tackled in the present thesis: first, the computation of neoclassical transport coefficients for general axisymmetric equilibria and arbitrary collisionality regime; second, the analysis of the electron temperature behaviour and transport modelling of plasma discharges in the Tokamak a configuration Variable (TCV); third, the modelling and simulation of the sawtooth activity with different plasma heating conditions. The work dedicated to neoclassical theory has been undertaken in order to first analytically identify a set of equations suited for implementation in existing Fokker-Planck codes. Modifications of these codes enabled us to compute the neoclassical transport coefficients considering different realistic magnetic equilibrium configurations and covering a large range of variation of three key parameters: aspect ratio, collisionality, and effective charge number. A comparison of the numerical results with an analytical limit has permitted the identification of two expressions for the trapped particle fraction, capable of encapsulating the geometrical effects and thus enabling each transport coefficient to be fitted with a single analytical function. This has allowed us to provide simple analytical formulae for all the neoclassical transport coefficients valid for arbitrary aspect ratio and collisionality in general realistic geometry. This work is particularly useful for a correct evaluation of the neoclassical contribution in tokamak scenarios with large bootstrap cur- rent fraction, or improved confinement regimes with low anomalous transport and for the determination of the plasma current density profile, since the plasma conductivity is usually assumed neoclassical. These results have been included in the plasma transport code

  5. Engineering of Cellobiose Dehydrogenases for Improved Glucose Sensitivity and Reduced Maltose Affinity

    DEFF Research Database (Denmark)

    Ortiz, Roberto; Rahman, Mahbubur; Zangrilli, Beatrice

    2017-01-01

    Cellobiose dehydrogenase (CDH) is a fungal extracellular flavocytochrome capable of direct electron transfer (DET). Unlike other CDHs, the pH optimum for CDHs from Corynascus thermophilus (CtCDH) and Humicola insolens (HiCDH) is close to the human physiological pH in blood (7.4). These are......, therefore, interesting candidates for glucose measurements in human blood and the application in enzymatic fuel cells is, however, limited by their relatively low activity with this substrate. In this work, the substrate specificities of CtCDH and HiCDH have been altered by a single cysteine to tyrosine...... substitution in the active sites of CtCDH (position 291) and HiCDH (position 285), which resulted in improved kinetic constants with glucose while decreasing the activity with several disaccharides, including maltose. The DET properties of the generated CDH variants were tested in the absence...

  6. Function of C-terminal hydrophobic region in fructose dehydrogenase

    International Nuclear Information System (INIS)

    Sugimoto, Yu; Kawai, Shota; Kitazumi, Yuki; Shirai, Osamu; Kano, Kenji

    2015-01-01

    Fructose dehydrogenase (FDH) catalyzes oxidation of D-fructose into 2-keto-D-fructose and is one of the enzymes allowing a direct electron transfer (DET)-type bioelectrocatalysis. FDH is a heterotrimeric membrane-bound enzyme (subunit I, II, and III) and subunit II has a C terminal hydrophobic region (CHR), which was expected to play a role in anchoring to membranes from the amino acid sequence. We have constructed a mutated FDH lacking of CHR (ΔchrFDH). Contrary to the expected function of CHR, ΔchrFDH is expressed in the membrane fraction, and subunit I/III subcomplex (ΔcFDH) is also expressed in a similar activity level but in the soluble fraction. In addition, the enzyme activity of the purified ΔchrFDH is about one twentieth of the native FDH. These results indicate that CHR is concerned with the binding between subunit I(/III) and subunit II and then with the enzyme activity. ΔchrFDH has clear DET activity that is larger than that expected from the solution activity, and the characteristics of the catalytic wave of ΔchrFDH are very similar to those of FDH. The deletion of CHR seems to increase the amounts of the enzyme with the proper orientation for the DET reaction at electrode surfaces. Gel filtration chromatography coupled with urea treatment shows that the binding in ΔchrFDH is stronger than that in FDH. It can be considered that the rigid binding between subunit I(/III) and II without CHR results in a conformation different from the native one, which leads to the decrease in the enzyme activity in solution

  7. Changes in mitochondrial electron transport chain activity during insect metamorphosis.

    Science.gov (United States)

    Chamberlin, M E

    2007-02-01

    The midgut of the tobacco hornworm (Manduca sexta) is a highly aerobic tissue that is destroyed by programmed cell death during larval-pupal metamorphosis. The death of the epithelium begins after commitment to pupation, and the oxygen consumption of isolated midgut mitochondria decreases soon after commitment. To assess the role of the electron transport chain in this decline in mitochondrial function, the maximal activities of complexes I-IV of the respiratory chain were measured in isolated midgut mitochondria. Whereas there were no developmental changes in the activity of complex I or III, activities of complexes II and IV [cytochrome c oxidase (COX)] were higher in mitochondria from precommitment than postcommitment larvae. This finding is consistent with a higher rate of succinate oxidation in mitochondria isolated from precommitment larvae and reveals that the metamorphic decline in mitochondrial respiration is due to the targeted destruction or inactivation of specific sites within the mitochondria, rather than the indiscriminate destruction of the organelles. The COX turnover number (e- x s(-1) x cytochrome aa3(-1)) was greater for the enzyme from precommitment than postcommitment larvae, indicating a change in the enzyme structure and/or its lipid environment during the early stages of metamorphosis. The turnover number of COX in the intact mitochondria (in organello COX) was also lower in postcommitment larvae. In addition to changes in the protein or membrane phospholipids, the metamorphic decline in this rate constant may be a result of the observed loss of endogenous cytochrome c.

  8. Anti-inflammatory effect of a selective 11β-hydroxysteroid dehydrogenase type 1 inhibitor via the stimulation of heme oxygenase-1 in LPS-activated mice and J774.1 murine macrophages

    Directory of Open Access Journals (Sweden)

    Sung Bum Park

    2016-08-01

    Full Text Available 11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1 converts inactive cortisone to the active cortisol. 11β-HSD1 may be involved in the resolution of inflammation. In the present study, we investigate the anti-inflammatory effects of 2-(3-benzoyl-4-hydroxy-1,1-dioxo-2H-1,2-benzothiazine-2-yl-1-phenylethanone (KR-66344, a selective 11β-HSD1 inhibitor, in lipopolysaccharide (LPS-activated C57BL/6J mice and macrophages. LPS increased 11β-HSD1 activity and expression in macrophages, which was inhibited by KR-66344. In addition, KR-66344 increased survival rate in LPS treated C57BL/6J mice. HO-1 mRNA expression level was increased by KR-66344, and this effect was reversed by the HO competitive inhibitor, ZnPP, in macrophages. Moreover, ZnPP reversed the suppression of ROS formation and cell death induced by KR-66344. ZnPP also suppressed animal survival rate in LPS plus KR-66344 treated C57BL/6J mice. In the spleen of LPS-treated mice, KR-66344 prevented cell death via suppression of inflammation, followed by inhibition of ROS, iNOS and COX-2 expression. Furthermore, LPS increased NFκB-p65 and MAPK phosphorylation, and these effects were abolished by pretreatment with KR-66344. Taken together, KR-66344 protects against LPS-induced animal death and spleen injury by inhibition of inflammation via induction of HO-1 and inhibition of 11β-HSD1 activity. Thus, we concluded that the selective 11β-HSD1 inhibitor may provide a novel strategy in the prevention/treatment of inflammatory disorders in patients.

  9. Redox-flexible NADH oxidase biosensor: A platform for various dehydrogenase bioassays and biosensors

    International Nuclear Information System (INIS)

    Serban, Simona; El Murr, Nabil

    2006-01-01

    A generic amperometric bioassay based on the enzymatic oxidation catalysed by the stable NADH oxidase (NAox) from Thermus thermophilus has been developed for NADH measurements. The NAox uses O 2 as its natural electron acceptor and produces H 2 O 2 in a two-electron process. Electrochemical and spectrophotometric experiments showed that the NAox used in this work, presents a very good activity towards its substrate and, in contrary to previously mentioned NADH oxidases, does not require the addition of any exogenous flavin cofactor neither to promote nor to maintain its activity. In addition, the NAox used also works with artificial electron acceptors like ferrocene derivatives. O 2 was successfully replaced by redox mediators such as hydroxymethyl ferrocene (FcCH 2 OH) for the regeneration of the active enzyme. Combining the NAox with the mediator and the horseradish peroxidase we developed an original, high sensitive 'redox-flexible' NADH amperometric bioassay working in a large window of applied potentials in both oxidation and reduction modes. The biosensor has a continuous and complementary linearity range permitting to measure NADH concentrations starting from 5 x 10 -6 M in reduction until 2 x 10 3 M in oxidation. This redox-flexibility allows choosing the applied potential in order to avoid electrochemical interferences. The association of the 'redox-flexible' concept with NADH dependent enzymes opens a novel strategy for dehydrogenases based bioassays and biosensors. The great number of dehydrogenases available makes the concept applicable for numerous substrates to analyse. Moreover it allows the development of a wide range of biosensors on the basis of a generic platform. This gives several advantages over the previous manufacturing techniques and offers a general and flexible scheme for the fabrication of biosensors presenting high sensitivities, wide calibration ranges and less affected by electrochemical interferences

  10. Structural Alterations of Lignins in Transgenic Poplars with Depressed Cinnamyl Alcohol Dehydrogenase or Caffeic Acid O-Methyltransferase Activity Have an Opposite Impact on the Efficiency of Industrial Kraft Pulping1

    Science.gov (United States)

    Lapierre, Catherine; Pollet, Brigitte; Petit-Conil, Michel; Toval, Gabriel; Romero, Javier; Pilate, Gilles; Leplé, Jean-Charles; Boerjan, Wout; Ferret, Valérie; De Nadai, Véronique; Jouanin, Lise

    1999-01-01

    We evaluated lignin profiles and pulping performances of 2-year-old transgenic poplar (Populus tremula × Populus alba) lines severely altered in the expression of caffeic acid/5-hydroxyferulic acid O-methyltransferase (COMT) or cinnamyl alcohol dehydrogenase (CAD). Transgenic poplars with CAD or COMT antisense constructs showed growth similar to control trees. CAD down-regulated poplars displayed a red coloration mainly in the outer xylem. A 90% lower COMT activity did not change lignin content but dramatically increased the frequency of guaiacyl units and resistant biphenyl linkages in lignin. This alteration severely lowered the efficiency of kraft pulping. The Klason lignin level of CAD-transformed poplars was slightly lower than that of the control. Whereas CAD down-regulation did not change the frequency of labile ether bonds or guaiacyl units in lignin, it increased the proportion of syringaldehyde and diarylpropane structures and, more importantly with regard to kraft pulping, of free phenolic groups in lignin. In the most depressed line, ASCAD21, a substantially higher content in free phenolic units facilitated lignin solubilization and fragmentation during kraft pulping. These results point the way to genetic modification of lignin structure to improve wood quality for the pulp industry. PMID:9880356

  11. Vitamin A decreases pre-receptor amplification of glucocorticoids in obesity: study on the effect of vitamin A on 11beta-hydroxysteroid dehydrogenase type 1 activity in liver and visceral fat of WNIN/Ob obese rats

    Directory of Open Access Journals (Sweden)

    Ayyalasomayajula Vajreswari

    2011-06-01

    Full Text Available Abstract Background 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1 catalyzes the conversion of inactive glucocorticoids to active glucocorticoids and its inhibition ameliorates obesity and metabolic syndrome. So far, no studies have reported the effect of dietary vitamin A on 11β-HSD1 activity in visceral fat and liver under normal and obese conditions. Here, we studied the effect of chronic feeding of vitamin A-enriched diet (129 mg/kg diet on 11β-HSD1 activity in liver and visceral fat of WNIN/Ob lean and obese rats. Methods Male, 5-month-old, lean and obese rats of WNIN/Ob strain (n = 16 for each phenotype were divided into two subgroups consisting of 8 rats of each phenotype. Control groups received stock diet containing 2.6 mg vitamin A/kg diet, where as experimental groups received diet containing 129 mg vitamin A/Kg diet for 20 weeks. Food and water were provided ad libitum. At the end of the experiment, tissues were collected and 11β-HSD1 activity was assayed in liver and visceral fat. Results Vitamin A supplementation significantly decreased body weight, visceral fat mass and 11β-HSD1 activity in visceral fat of WNIN/Ob obese rats. Hepatic 11β-HSD1 activity and gene expression were significantly reduced by vitamin A supplementation in both the phenotypes. CCAAT/enhancer binding protein α (C/EBPα, the main transcription factor essential for the expression of 11β-HSD1, decreased in liver of vitamin A fed-obese rats, but not in lean rats. Liver × receptor α (LXRα, a nuclear transcription factor which is known to downregulate 11β-HSD1 gene expression was significantly increased by vitamin A supplementation in both the phenotypes. Conclusions This study suggests that chronic consumption of vitamin A-enriched diet decreases 11β-HSD1 activity in liver and visceral fat of WNIN/Ob obese rats. Decreased 11β-HSD1 activity by vitamin A may result in decreased levels of active glucocorticoids in adipose tissue and possibly

  12. Purification and characterization of a thermostable glutamate dehydrogenase from a thermophilic bacterium isolated from a sterilization drying oven

    Directory of Open Access Journals (Sweden)

    Maximiliano J. Amenábar

    2012-02-01

    Full Text Available Glutamate dehydrogenase from axenic bacterial cultures of anew microorganism, called GWE1, isolated from the interior ofa sterilization drying oven, was purified by anion-exchange andmolecular-exclusion liquid chromatography. The apparent molecularmass of the native enzyme was 250.5 kDa and wasshown to be an hexamer with similar subunits of molecularmass 40.5 kDa. For glutamate oxidation, the enzyme showedan optimal pH and temperature of 8.0 and 70oC, respectively.In contrast to other glutamate dehydrogenases isolated frombacteria, the enzyme isolated in this study can use both NAD+and NADP+ as electron acceptors, displaying more affinity forNADP+ than for NAD+. No activity was detected with NADHor NADPH, 2-oxoglutarate and ammonia. The enzyme was exceptionallythermostable, maintaining more than 70% of activityafter incubating at 100oC for more than five hours suggestingbeing one of the most thermoestable enzymes reported inthe family of dehydrogenases. [BMB reports 2012; 45(2: 91-95

  13. Response of Chloroplast NAD(PH Dehydrogenase-Mediated Cyclic Electron Flow to a Shortage or Lack in Ferredoxin-Quinone Oxidoreductase-Dependent Pathway in Rice Following Short-Term Heat Stress

    Directory of Open Access Journals (Sweden)

    Jemaa eEssemine

    2016-03-01

    Full Text Available Cyclic electron flow around PSI can protect photosynthetic electron carriers under conditions of stromal over-reduction. The goal of the research reported in this paper was to investigate the responses of both PSI and PSII to a short-term heat stress in two rice lines with different capacities of cyclic electron transfer, i.e. Q4149 with a high capacity (hcef and C4023 with a low capacity (lcef. The absorbance change at 820 nm (ΔA820 was used here to assess the charge separation in the photosystem I (PSI reaction center (P700. The results obtained show that short-term heat stress abolishes the FQR-dependent CEF in rice and accelerates the initial rate of P700+ re-reduction. The P700+ amplitude was slightly increased at a moderate heat-stress (35°C because of a partial restriction of FQR but it was decreased following high heat-stress (42°C. Assessment of PSI and PSII activities shows that PSI is more susceptible to heat stress than photosystem II (PSII. Under high temperature, FQR-dependent CEF was completely removed and NDH-dependent CEF was up-regulated and strengthened to a higher extent in C4023 than in Q4149. Specifically, under normal growth temperature, hcef (Q4149 was characterized by higher FQR- and NDH-dependent CEF rates than lcef (C4023. Following thermal stress, the activation of NDH-pathway was 130% and 10% for C4023 and Q4149, respectively. Thus, the NDH-dependent CEF may constitute the second layer of plant protection and defence against heat stress after the main route, i.e. FQR-dependent CEF, reaches its capacity. We discuss the possibility that under high heat stress, the NDH pathway serves as a safety valve to dissipate excess energy by cyclic photophosphorylation and overcome the stroma over-reduction following inhibition of CO2 assimilation and any shortage or lack in the FQR pathway. The potential role of the NDH-dependent pathway during the evolution of C4 photosynthesis is briefly discussed.

  14. Interactions among the branched-chain amino acids and their effects on methionine utilization in growing pigs: effects on plasma amino- and keto-acid concentrations and branched-chain keto-acid dehydrogenase activity.

    Science.gov (United States)

    Langer, S; Scislowski, P W; Brown, D S; Dewey, P; Fuller, M F

    2000-01-01

    The present experiment was designed to elucidate the mechanism of the methionine-sparing effect of excess branched-chain amino acids (BCAA) reported in the previous paper (Langer & Fuller, 2000). Twelve growing gilts (30-35 kg) were prepared with arterial catheters. After recovery, they received for 7 d a semipurified diet with a balanced amino acid pattern. On the 7th day blood samples were taken before (16 h postabsorptive) and after the morning meal (4 h postprandial). The animals were then divided into three groups and received for a further 7 d a methionine-limiting diet (80% of requirement) (1) without any amino acid excess; (2) with excess leucine (50% over requirement); or (3) with excesses of all three BCAA (leucine, isoleucine, valine, each 50% over the requirement). On the 7th day blood samples were taken as in the first period, after which the animals were killed and liver and muscle samples taken. Plasma amino acid and branched-chain keto acid (BCKA) concentrations in the blood and branched-chain keto-acid dehydrogenase (BCKDH; EC 1.2.4.4) activity in liver and muscle homogenates were determined. Compared with those on the balanced diet, pigs fed on methionine-limiting diets had significantly lower (P < 0.05) plasma methionine concentrations in the postprandial but not in the postabsorptive state. There was no effect of either leucine or a mixture of all three BCAA fed in excess on plasma methionine concentrations. Excess dietary leucine reduced (P < 0.05) the plasma concentrations of isoleucine and valine in both the postprandial and postabsorptive states. Plasma concentrations of the BCKA reflected the changes in the corresponding amino acids. Basal BCKDH activity in the liver and total BCKDH activity in the biceps femoris muscle were significantly (P < 0.05) increased by excesses of leucine or all BCAA.

  15. Action of sulphite on plant malate dehydrogenase

    Energy Technology Data Exchange (ETDEWEB)

    Ziegler, I.

    1974-01-01

    SO/sub 3//sup 2 -/ acts on NAD- and NADP-dependent malate dehydrogenase in several ways. Firstly, SO/sub 3//sup 2 -/ favours the appearance of low MW species (65000 and 39000 daltons) in Sephadex gel chromatography. Secondly, the enzyme from which is obtained by gel chromatography with dithioerythritol plus nucleotide cofactor is changed in the presence of SO/sub 3//sup 2 -/. This is indicated by the appearance of a linear reaction (instead of curvilinear), and by the abolition of the biphasic sigmoidal kinetics on varying substrate and cofactor concentrations. Thus the inhibition of initial velocity at high substrate or cofactor concentrations is even more marked than at lower ones. Thirdly, SO/sub 3//sup 2 -/ strongly reduces the activity in substrate saturating conditions.

  16. Electron beam injection during active experiments. 1. Electromagnetic wave emissions

    International Nuclear Information System (INIS)

    Winglee, R.M.; Kellogg, P.J.

    1990-01-01

    During the active injection of an electron beam, a broad spectrum of waves is generated. In this paper examples of spectra from the recent Echo 7 experiment are presented. These results show that the characteristics of the emissions can change substantially with altitude. Two-dimensional (three velocity) relativistic electromagnetic particle simulations are used to investigate the changes in the plasma conditions required to account for the observed spectral variations. It is shown that many of these variations can be accounted for by assuming that the ratio of the electron plasma frequency ω pe to cyclotron frequency Ω e is less than unity at the lower altitudes of about 200 km and near or above unity at apogee of about 300 km. In the former case, whistlers with a cutoff at ω pe , lower hybrid and plasma waves are driven by the parallel beam energy while electromagnetic fundamental z mode and second harmonic x mode and electrostatic upper hybrid waves are driven by the perpendicular beam energy through the master instability. E x B drifts driven by perpendicular electric fields associated with the beam-plasma interaction can also be important in generating maser emission, particularly for field-aligned injection where there is no intrinsic perpendicular beam energy. The power in the electrostatic waves is a few percent of the beam energy and that in the electromagnetic waves a few tenths of a percent. In the latter case, where ω pe /Ω e increases above unity, emission in the fundamental z mode and second harmonic x mode become suppressed

  17. Mutant alcohol dehydrogenase leads to improved ethanol tolerance in Clostridium thermocellum

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Steven D [ORNL; Guss, Adam M [ORNL; Karpinets, Tatiana V [ORNL; Parks, Jerry M [ORNL; Smolin, Nikolai [ORNL; Yang, Shihui [ORNL; Land, Miriam L [ORNL; Klingeman, Dawn Marie [ORNL; Bhandiwad, Ashwini [Thayer School of Engineering at Dartmouth; Rodriguez, Jr., Miguel [ORNL; Raman, Babu [Dow Chemical Company, The; Shao, Xiongjun [Thayer School of Engineering at Dartmouth; Mielenz, Jonathan R [ORNL; Smith, Jeremy C [ORNL; Keller, Martin [ORNL; Lynd, Lee R [Thayer School of Engineering at Dartmouth

    2011-01-01

    Clostridium thermocellum is a thermophilic, obligately anaerobic, Gram-positive bacterium that is a candidate microorganism for converting cellulosic biomass into ethanol through consolidated bioprocessing. Ethanol intolerance is an important metric in terms of process economics, and tolerance has often been described as a complex and likely multigenic trait for which complex gene interactions come into play. Here, we resequence the genome of an ethanol-tolerant mutant, show that the tolerant phenotype is primarily due to a mutated bifunctional acetaldehyde-CoA/alcohol dehydrogenase gene (adhE), hypothesize based on structural analysis that cofactor specificity may be affected, and confirm this hypothesis using enzyme assays. Biochemical assays confirm a complete loss of NADH-dependent activity with concomitant acquisition of NADPH-dependent activity, which likely affects electron flow in the mutant. The simplicity of the genetic basis for the ethanol-tolerant phenotype observed here informs rational engineering of mutant microbial strains for cellulosic ethanol production.

  18. ald of Mycobacterium tuberculosis Encodes both the Alanine Dehydrogenase and the Putative Glycine Dehydrogenase

    Science.gov (United States)

    Giffin, Michelle M.; Modesti, Lucia; Raab, Ronald W.; Wayne, Lawrence G.

    2012-01-01

    The putative glycine dehydrogenase of Mycobacterium tuberculosis catalyzes the reductive amination of glyoxylate to glycine but not the reverse reaction. The enzyme was purified and identified as the previously characterized alanine dehydrogenase. The Ald enzyme was expressed in Escherichia coli and had both pyruvate and glyoxylate aminating activities. The gene, ald, was inactivated in M. tuberculosis, which resulted in the loss of all activities. Both enzyme activities were found associated with the cell and were not detected in the extracellular filtrate. By using an anti-Ald antibody, the protein was localized to the cell membrane, with a smaller fraction in the cytosol. None was detected in the extracellular medium. The ald knockout strain grew without alanine or glycine and was able to utilize glycine but not alanine as a nitrogen source. Transcription of ald was induced when alanine was the sole nitrogen source, and higher levels of Ald enzyme were measured. Ald is proposed to have several functions, including ammonium incorporation and alanine breakdown. PMID:22210765

  19. 5´AMP activated protein kinase α2 controls substrate metabolism during post-exercise recovery via regulation of pyruvate dehydrogenase kinase 4

    DEFF Research Database (Denmark)

    Fritzen, Andreas Mæchel; Lundsgaard, Annemarie; Jeppesen, Jacob

    2015-01-01

    after prolonged exercise and during the following six hours post exercise in 5´AMP activated protein kinase (AMPK)α2 and α1 knock-out (KO) and wild type (WT) mice with free access to food. Substrate oxidation was similar during exercise at the same relative intensity between genotypes. During post...

  20. Increase in activity, glycosylation and expression of cytokinin oxidase/dehydrogenase during the senescence of barley leaf segments in the dark

    Czech Academy of Sciences Publication Activity Database

    Conrad, K.; Motyka, Václav; Schlüter, T.

    2007-01-01

    Roč. 130, č. 4 (2007), s. 572-579 ISSN 0031-9317 R&D Projects: GA ČR GA206/03/0313 Institutional research plan: CEZ:AV0Z50380511 Source of funding: V - iné verejné zdroje Keywords : OXIDASE ACTIVITY * GENE-EXPRESSION * ZEA - MAYS Subject RIV: EF - Botanics Impact factor: 2.192, year: 2007

  1. Characterization of the L-lactate dehydrogenase from Aggregatibacter actinomycetemcomitans.

    Directory of Open Access Journals (Sweden)

    Stacie A Brown

    Full Text Available Aggregatibacter actinomycetemcomitans is a Gram-negative opportunistic pathogen and the proposed causative agent of localized aggressive periodontitis. A. actinomycetemcomitans is found exclusively in the mammalian oral cavity in the space between the gums and the teeth known as the gingival crevice. Many bacterial species reside in this environment where competition for carbon is high. A. actinomycetemcomitans utilizes a unique carbon resource partitioning system whereby the presence of L-lactate inhibits uptake of glucose, thus allowing preferential catabolism of L-lactate. Although the mechanism for this process is not fully elucidated, we previously demonstrated that high levels of intracellular pyruvate are critical for L-lactate preference. As the first step in L-lactate catabolism is conversion of L-lactate to pyruvate by lactate dehydrogenase, we proposed a model in which the A. actinomycetemcomitans L-lactate dehydrogenase, unlike homologous enzymes, is not feedback inhibited by pyruvate. This lack of feedback inhibition allows intracellular pyruvate to rise to levels sufficient to inhibit glucose uptake in other bacteria. In the present study, the A. actinomycetemcomitans L-lactate dehydrogenase was purified and shown to convert L-lactate, but not D-lactate, to pyruvate with a K(m of approximately 150 microM. Inhibition studies reveal that pyruvate is a poor inhibitor of L-lactate dehydrogenase activity, providing mechanistic insight into L-lactate preference in A. actinomycetemcomitans.

  2. Pyruvate dehydrogenase complex and lactate dehydrogenase as targets for therapy of acute liver failure.

    Science.gov (United States)

    Ferriero, Rosa; Nusco, Edoardo; De Cegli, Rossella; Carissimo, Annamaria; Manco, Giuseppe; Brunetti-Pierri, Nicola

    2018-03-23

    Acute liver failure is a rapidly progressive deterioration of hepatic function resulting in high mortality and morbidity. Metabolic enzymes can translocate in the nucleus to regulate histone acetylation and gene expression. Levels and activities of pyruvate dehydrogenase complex (PDHC) and lactate dehydrogenase (LDH) were evaluated in nuclear fractions of livers of mice exposed to various hepatotoxins including CD95-Ab, α-amanitin, and acetaminophen. Whole-genome gene expression profiling by RNA-seq was performed in livers of mice with acute liver failure and analyzed by Gene Ontology Enrichment Analysis. Efficacy of histone acetyltransferase inhibitor garcinol and LDH inhibitor galloflavin at reducing liver damage was evaluated in mice with induced hepatotoxicity. Levels and activities of PDHC and LDH were increased in cytoplasmatic and nuclear fractions of livers of mice with acute liver failure. The increase of nuclear PDHC and LDH was associated with increased concentrations of acetyl-coA and lactate in nuclear fractions, and histone H3 hyper-acetylation. Gene expression in livers of mice with acute liver failure suggested that increased histone H3 acetylation induces the expression of genes related to response to damage. Reduced histone acetylation by the histone acetyltransferase inhibitor garcinol decreased liver damage and improved survival in mice with acute liver failure. Knock-down of PDHC or LDH improved viability in cells exposed to a pro-apoptotic stimulus. Treatment with the LDH inhibitor galloflavin that was also found to inhibit PDHC, reduced hepatic necrosis, apoptosis, and expression of pro-inflammatory cytokines in mice with acute liver failure. Mice treated with galloflavin also showed a dose-response increase in survival. PDHC and LDH translocate to the nucleus and are targets for therapy of acute liver failure. Acute liver failure is a rapidly progressive and life-threatening deterioration of liver function resulting in high mortality and

  3. Effects of the electron-phonon coupling activation in collision cascades

    Energy Technology Data Exchange (ETDEWEB)

    Zarkadoula, Eva, E-mail: zarkadoulae@ornl.gov [Materials Science & Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Samolyuk, German [Materials Science & Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Weber, William J. [Materials Science & Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States); Department of Materials Science & Engineering, University of Tennessee, Knoxville, TN 37996 (United States)

    2017-07-15

    Using the two-temperature (2T-MD) model in molecular dynamics simulations, we investigate the condition of switching the electronic stopping term off when the electron-phonon coupling is activated in the damage production due to 50 keV Ni ion cascades in Ni and equiatomic NiFe. Additionally, we investigate the effect of the electron-phonon coupling activation time in the damage production. We find that the switching condition has negligible effect in the produced damage, while the choice of the activation time of the electron-phonon coupling can affect the amount of surviving damage. - Highlights: •The electron-phonon interactions in irradiation affect the energy dissipation. •The resulting damage depends on the electron-phonon interaction activation time. •The electronic stopping acts on the ions before the electron-phonon interactions.

  4. Mitochondrial type II NAD(PH dehydrogenases in fungal cell death

    Directory of Open Access Journals (Sweden)

    A. Pedro Gonçalves

    2015-03-01

    Full Text Available During aerobic respiration, cells produce energy through oxidative phosphorylation, which includes a specialized group of multi-subunit complexes in the inner mitochondrial membrane known as the electron transport chain. However, this canonical pathway is branched into single polypeptide alternative routes in some fungi, plants, protists and bacteria. They confer metabolic plasticity, allowing cells to adapt to different environmental conditions and stresses. Type II NAD(PH dehydrogenases (also called alternative NAD(PH dehydrogenases are non-proton pumping enzymes that bypass complex I. Recent evidence points to the involvement of fungal alternative NAD(PH dehydrogenases in the process of programmed cell death, in addition to their action as overflow systems upon oxidative stress. Consistent with this, alternative NAD(PH dehydrogenases are phylogenetically related to cell death - promoting proteins of the apoptosis-inducing factor (AIF-family.

  5. Zinc and glutamate dehydrogenase in putative glutamatergic brain structures.

    Science.gov (United States)

    Wolf, G; Schmidt, W

    1983-01-01

    A certain topographic parallelism between the distribution of histochemically (TIMM staining) identified zinc and putative glutamatergic structures in the rat brain was demonstrated. Glutamate dehydrogenase as a zinc containing protein is in consideration to be an enzyme synthesizing transmitter glutamate. In a low concentration range externally added zinc ions (10(-9) to 10(-7) M) induced an increase in the activity of glutamate dehydrogenase (GDH) originating from rat hippocampal formation, neocortex, and cerebellum up to 142.4%. With rising molarity of Zn(II) in the incubation medium, the enzyme of hippocampal formation and cerebellum showed a biphasic course of activation. Zinc ions of a concentration higher than 10(-6) M caused a strong inhibition of GDH. The effect of Zn(II) on GDH originating from spinal ganglia and liver led only to a decrease of enzyme activity. These results are discussed in connection with a functional correlation between zinc and putatively glutamatergic system.

  6. The dehydrogenase region of the NADPH oxidase component Nox2 acts as a protein disulfide isomerase (PDI) resembling PDIA3 with a role in the binding of the activator protein p67phox

    Science.gov (United States)

    Bechor, Edna; Dahan, Iris; Fradin, Tanya; Berdichevsky, Yevgeny; Zahavi, Anat; Rafalowski, Meirav; Federman-Gross, Aya; Pick, Edgar

    2015-02-01

    The superoxide (O2.-)-generating NADPH oxidase of phagocytes consists of a membrane component, cytochrome b558 (a heterodimer of Nox2 and p22phox), and four cytosolic components, p47phox, p67phox, p40phox, and Rac. The catalytic component, responsible for O2.- generation, is Nox2. It is activated by the interaction of the dehydrogenase region (DHR) of Nox2 with the cytosolic components, principally with p67phox. Using a peptide-protein binding assay, we found that Nox2 peptides containing a 369CysGlyCys371 triad (CGC) bound p67phox with high affinity, dependent upon the establishment of a disulfide bond between the two cysteines. Serially truncated recombinant Nox2 DHR proteins bound p67phox only when they comprised the CGC triad. CGC resembles the catalytic motif (CGHC) of protein disulfide isomerases (PDIs). This led to the hypothesis that Nox2 establishes disulfide bonds with p67phox via a thiol-dilsulfide exchange reaction and, thus, functions as a PDI. Evidence for this was provided by the following: 1. Recombinant Nox2 protein, which contained the CGC triad, exhibited PDI-like disulfide reductase activity; 2. Truncation of Nox2 C-terminal to the CGC triad or mutating C369 and C371 to R, resulted in loss of PDI activity; 3. Comparison of the sequence of the DHR of Nox2 with PDI family members revealed three small regions of homology with PDIA3; 4. Two monoclonal anti-Nox2 antibodies, with epitopes corresponding to regions of Nox2/PDIA3 homology, reacted with PDIA3 but not with PDIA1; 5. A polyclonal anti-PDIA3 (but not an anti-PDIA1) antibody reacted with Nox2; 6. p67phox, in which all cysteines were mutated to serines, lost its ability to bind to a Nox2 peptide containing the CGC triad and had an impaired capacity to support oxidase activity in vitro. We propose a model of oxidase assembly in which binding of p67phox to Nox2 via disulfide bonds, by virtue of the intrinsic PDI activity of Nox2, stabilizes the primary interaction between the two components.

  7. Light and electron microscope assessment of the lytic activity of ...

    African Journals Online (AJOL)

    The Microcystis cells were exposed to copper, B. mycoides B16 and Triton X-100, in order to ascertain the level of cell membrane damage. The membrane cell damage ... The electron microscopy observations appeared to reveal at least two mechanisms of Microcystis lysis (contact and parasitism). The light and electron ...

  8. Electron-capture ratios in radio-active decay

    International Nuclear Information System (INIS)

    Pelt, J. van.

    1978-01-01

    A review of the theory of electron capture is given and expressions for the electron-capture ratios derived. Attention is paid to the calculations of exchange and overlap correction factors. The theoretical results are then compared with experimental values on the basis of two recently published compilations. The experimental set-up used in this investigation is described and the analysis of the scintillation spectra discussed. Measurements on 131 Ba, 106 Agsup(m) and 196 Au are described and values derived for the exchange and overlap corrections and for the atomic electron-capture transition energy Qsub(EC). (Auth.)

  9. Characterization of a dehydrogenase activity responsible for oxidation of 11-cis-retinol in the retinal pigment epithelium of mice with a disrupted RDH5 gene. A model for the human hereditary disease fundus albipunctatus.

    NARCIS (Netherlands)

    Jang, G.F.; Hooser, J.P. van; Kuksa, V.; McBee, J.K.; He, Y.G.; Janssen, J.J.M.; Driessen, C.A.G.G.; Palczewski, K.

    2001-01-01

    In the vertebrate retina, the final step of visual chromophore production is the oxidation of 11-cis-retinol to 11-cis-retinal. This reaction is catalyzed by 11-cis-retinol dehydrogenases (11-cis-RDHs), prior to the chromophore rejoining with the visual pigment apo-proteins. The RDH5 gene encodes a

  10. Metabolic Engineering of Mannitol Production in Lactococcus lactis: Influence of Overexpression of Mannitol 1-Phosphate Dehydrogenase in Different Genetic Backgrounds

    OpenAIRE

    Wisselink, H. Wouter; Mars, Astrid E.; van der Meer, Pieter; Eggink, Gerrit; Jeroen Hugenholtz

    2004-01-01

    To obtain a mannitol-producing Lactococcus lactis strain, the mannitol 1-phosphate dehydrogenase gene (mtlD) from Lactobacillus plantarum was overexpressed in a wild-type strain, a lactate dehydrogenase(LDH)-deficient strain, and a strain with reduced phosphofructokinase activity. High-performance liquid chromatography and 13C nuclear magnetic resonance analysis revealed that small amounts (

  11. Metabolic Engineering of Mannitol Production in Lactococcus lactis: Influence of Overexpression of Mannitol 1-Phosphate Dehydrogenase in Different Genetic Backgrounds

    NARCIS (Netherlands)

    Wisselink, H.W.; Mars, A.E.; Meer, van der P.; Eggink, G.; Hugenholtz, J.

    2004-01-01

    To obtain a mannitol-producing Lactococcus lactis strain, the mannitol 1-phosphate dehydrogenase gene (mtlD) from Lactobacillus plantarum was overexpressed in a wild-type strain, a lactate dehydrogenase(LDH)-deficient strain, and a strain with reduced phosphofructokinase activity. High-performance

  12. 76 FR 40454 - Proposed Information Collection (VSO Access to VHA Electronic Health Records) Activity; Comment...

    Science.gov (United States)

    2011-07-08

    ... Access to VHA Electronic Health Records) Activity; Comment Request AGENCY: Veterans Health Administration... Access to VHA Electronic Health Records, VA Form 10- 0400. OMB Control Number: 2900-0710. Type of Review... were granted power of attorney by veterans who have medical information recorded in VHA electronic...

  13. Cloning, purification and crystallization of Thermus thermophilus proline dehydrogenase

    Energy Technology Data Exchange (ETDEWEB)

    White, Tommi A.; Tanner, John J., E-mail: tannerjj@missouri.edu [Departments of Chemistry and Biochemistry, University of Missouri-Columbia, Columbia, Missouri 65211 (United States)

    2005-08-01

    Cloning, purification and crystallization of T. thermophilus proline dehydrogenase is reported. The detergent n-octyl β-d-glucopyranoside was used to reduce polydispersity, which enabled crystallization. Nature recycles l-proline by converting it to l-glutamate. This four-electron oxidation process is catalyzed by the two enzymes: proline dehydrogenase (PRODH) and Δ{sup 1}-pyrroline-5-carboxylate dehydrogenase. This note reports the cloning, purification and crystallization of Thermus thermophilus PRODH, which is the prototype of a newly discovered superfamily of bacterial monofunctional PRODHs. The results presented here include production of a monodisperse protein solution through use of the detergent n-octyl β-d-glucopyranoside and the growth of native crystals that diffracted to 2.3 Å resolution at Advanced Light Source beamline 4.2.2. The space group is P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 82.2, b = 89.6, c = 94.3 Å. The asymmetric unit is predicted to contain two protein molecules and 46% solvent. Molecular-replacement trials using a fragment of the PRODH domain of the multifunctional Escherichia coli PutA protein as the search model (24% amino-acid sequence identity) did not produce a satisfactory solution. Therefore, the structure of T. thermophilus PRODH will be determined by multiwavelength anomalous dispersion phasing using a selenomethionyl derivative.

  14. Cloning, purification and crystallization of Thermus thermophilus proline dehydrogenase

    International Nuclear Information System (INIS)

    White, Tommi A.; Tanner, John J.

    2005-01-01

    Cloning, purification and crystallization of T. thermophilus proline dehydrogenase is reported. The detergent n-octyl β-d-glucopyranoside was used to reduce polydispersity, which enabled crystallization. Nature recycles l-proline by converting it to l-glutamate. This four-electron oxidation process is catalyzed by the two enzymes: proline dehydrogenase (PRODH) and Δ 1 -pyrroline-5-carboxylate dehydrogenase. This note reports the cloning, purification and crystallization of Thermus thermophilus PRODH, which is the prototype of a newly discovered superfamily of bacterial monofunctional PRODHs. The results presented here include production of a monodisperse protein solution through use of the detergent n-octyl β-d-glucopyranoside and the growth of native crystals that diffracted to 2.3 Å resolution at Advanced Light Source beamline 4.2.2. The space group is P2 1 2 1 2 1 , with unit-cell parameters a = 82.2, b = 89.6, c = 94.3 Å. The asymmetric unit is predicted to contain two protein molecules and 46% solvent. Molecular-replacement trials using a fragment of the PRODH domain of the multifunctional Escherichia coli PutA protein as the search model (24% amino-acid sequence identity) did not produce a satisfactory solution. Therefore, the structure of T. thermophilus PRODH will be determined by multiwavelength anomalous dispersion phasing using a selenomethionyl derivative

  15. Effect of Punica granatum fruit peel on glucose-6-phosphate dehydrogenase and malate dehydrogenase in amphistome Gastrothylax indicus.

    Science.gov (United States)

    Aggarwal, Rama; Bagai, Upma

    2017-03-01

    Increasing anthelmintic resistance and the impact of conventional anthelmintics on the environment, it is important to look for alternative strategies against helminth parasite in sheep. Important lipogenic enzymes like glucose-6-phosphate dehydrogenase (G-6-PDH) and malate dehydrogenase (MDH) show subcellular distribution pattern. Activity of G-6-PDH was largely restricted to cytosolic fraction while MDH was found in both cytosolic and mitochondrial fraction in Gastrothylax indicus. Following in vitro treatment with ethanolic and aqueous extracts of Punica granatum fruit peel and commercial anthelmintic, albendazole G-6-PDH activity was decreased by 19-32 %, whereas MDH was suppressed by 24-41 %, compared to the respective control. Albendazole was quite effective when compared with negative control and both the extracts. The results indicate that phytochemicals of plant may act as potential vermifuge or vermicide.

  16. Demonstration of glucose-6-phosphate dehydrogenase in rat Kupffer cells by a newly-developed ultrastructural enzyme-cytochemistry

    Directory of Open Access Journals (Sweden)

    S Matsubara

    2009-06-01

    Full Text Available Although various tissue macrophages possess high glucose- 6-phosphate dehydrogenase (G6PD activity, which is reported to be closely associated with their phagocytotic/bactericidal function, the fine subcellular localization of this enzyme in liver resident macrophages (Kupffer cells has not been determined.We have investigated the subcellular localization of G6PD in Kupffer cells in rat liver, using a newly developed enzyme-cytochemical (copper-ferrocyanide method. Electron-dense precipitates indicating G6PD activity were clearly visible in the cytoplasm and on the cytosolic side of the endoplasmic reticulum of Kupffer cells. Cytochemical controls ensured specific detection of the enzymatic activity. Rat Kupffer cells abundantly possessed enzyme-cytochemically detectable G6PD activity. Kupffer cell G6PD may play a role in liver defense by delivering NADPH to NADPH-dependent enzymes. G6PD enzyme-cytochemistry may be a useful tool for the study of Kupffer cell functions.

  17. Six hours of resting platelet concentrates stored at 22-24 ºC for 48 hours in permeable bags preserved pH, swirling and lactate dehydrogenase better and caused less platelet activation.

    Science.gov (United States)

    Naghadeh, Hossin T; Badlou, Bahram A; Ferizhandy, Ali S; Mohammadreza, Tabatabai S; Shahram, Vaeli

    2013-07-01

    During transportation, platelet concentrates (PC) usually undergo a long period without agitation. Whether this interruption improves quality and viability or, contrariwise, has deleterious effects on PC stored for 48 hours (h) is unknown. The aim of this study was to investigate the effects of metabolic resting (6 h of interruption of agitation) vs continue agitation of PC stored for 48 h in the blood bank of Tehran. PC were prepared from platelet-rich plasma and stored in permeable bags in a shaker/incubator for 42 h at room temperature (20-24 ºC). Then, simply by stopping the agitator, the PC remained stationary ("resting") without agitation for 6 h (WCA6h), prior to transfusion. In vitro measurements of platelet quality were carried out just after completion of the resting period and the results were compared with those of PC continuously agitated in the same day (designated as the control group, CA6h). The in vitro variables measured were swirling, ristocetin-induced aggregation (GPIb-related function), lactate dehydrogenase (LDH) concentration, platelet factor 4 (PF4) release and P-selectin expression (activation markers). The mean platelet counts of the control group (CA6h) and rested (WCA6h) PC were not statistically different (P =0.548). Likewise, the mean pH values were not significantly different: WCA6h (7.16 ± 0.08) and CA6h (7.22 ± 0.16) (P =0.300). Although ristocetin-induced aggregation did not differ significantly between CA6h (79.2 ± 4.4) and WCA6h (66.65 ± 28.55) (P =0.186), WCA6h showed significantly less PFA release (P =0.015) and lower P-selectin expression (P =0.006). We observed that PC stored under agitation for 42 h at 22-24 ºC in permeable bags and then rested for 6 h had better preserved pH, swirling and LDH and less platelet activation then PC kept under continuous agitation for the whole 48 h storage period.

  18. Eucalypt NADP-Dependent Isocitrate Dehydrogenase1

    Science.gov (United States)

    Boiffin, Vincent; Hodges, Michael; Gálvez, Susana; Balestrini, Raffaella; Bonfante, Paola; Gadal, Pierre; Martin, Francis

    1998-01-01

    NADP-dependent isocitrate dehydrogenase (NADP-ICDH) activity is increased in roots of Eucalyptus globulus subsp. bicostata ex Maiden Kirkp. during colonization by the ectomycorrhizal fungus Pisolithus tinctorius Coker and Couch. To investigate the regulation of the enzyme expression, a cDNA (EgIcdh) encoding the NADP-ICDH was isolated from a cDNA library of E. globulus-P. tinctorius ectomycorrhizae. The putative polypeptide sequence of EgIcdh showed a high amino acid similarity with plant NADP-ICDHs. Because the deduced EgICDH protein lacks an amino-terminal targeting sequence and shows highest similarity to plant cytosolic ICDHs, it probably represents a cytoplasmic isoform. RNA analysis showed that the steady-state level of EgIcdh transcripts was enhanced nearly 2-fold in ectomycorrhizal roots compared with nonmycorrhizal roots. Increased accumulation of NADP-ICDH transcripts occurred as early as 2 d after contact and likely led to the observed increased enzyme activity. Indirect immunofluorescence microscopy indicated that NADP-ICDH was preferentially accumulated in the epidermis and stele parenchyma of nonmycorrhizal and ectomycorrhizal lateral roots. The putative role of cytosolic NADP-ICDH in ectomycorrhizae is discussed. PMID:9662536

  19. Glucose-6-phosphate dehydrogenase deficiency in Singapore.

    Science.gov (United States)

    Quak, S H; Saha, N; Tay, J S

    1996-01-01

    Glucose-6-phosphate dehydrogenase (G6PD) in man is an X-linked enzyme. The deficiency of this enzyme is one of the most common inherited metabolic disorders in man. In Singapore, three clinical syndromes associated with G6PD deficiency had been described: severe haemolysis in neonates with kernicterus, haemoglobinuria and "viral hepatitis"-like syndrome. The human G6PD monomer consists of 515 amino acids. Only the tetrameric or dimeric forms composed of a single type subunit are catylitically active. The complete amino acid sequence of G6PD had been elucidated in man and various other animals. The region of high homology among the enzymes of various animals is presumably functionally active. Among the Chinese in Singapore, three common molecular variants had been identified: Canton (nt 1376 G --> T), Kaiping (nt 1388 G --> A) and Mediterranean (nt 563 C --> T) in frequencies of 24%, 21% and 10% respectively. In addition, two common mutants (Gaozhou, nt 95 A --> G and Chinese 5, nt 1024 C --> T) have been detected in Singapore Chinese in low frequencies. In Malays, 6 different deficient variants are known in Singapore (3 new, 1 Mahidol, 1 Indonesian and 1 Mediterranean).

  20. Histochemical localization of cytokinin oxidase/dehydrogenase ...

    African Journals Online (AJOL)

    Jane

    2011-08-15

    dehydrogenase, Withania somnifera, CKX localization. INTRODUCTION. Cytokinin (Ck) is a plant hormone that plays a crucial role in many fundamental processes of plant development throughout the life cycle. These include ...

  1. Cloning, functional expression and characterization of a bifunctional 3-hydroxybutanal dehydrogenase /reductase involved in acetone metabolism by Desulfococcus biacutus.

    Science.gov (United States)

    Frey, Jasmin; Rusche, Hendrik; Schink, Bernhard; Schleheck, David

    2016-11-25

    The strictly anaerobic, sulfate-reducing bacterium Desulfococcus biacutus can utilize acetone as sole carbon and energy source for growth. Whereas in aerobic and nitrate-reducing bacteria acetone is activated by carboxylation with CO 2 to acetoacetate, D. biacutus involves CO as a cosubstrate for acetone activation through a different, so far unknown pathway. Proteomic studies indicated that, among others, a predicted medium-chain dehydrogenase/reductase (MDR) superfamily, zinc-dependent alcohol dehydrogenase (locus tag DebiaDRAFT_04514) is specifically and highly produced during growth with acetone. The MDR gene DebiaDRAFT_04514 was cloned and overexpressed in E. coli. The purified recombinant protein required zinc as cofactor, and accepted NADH/NAD + but not NADPH/NADP + as electron donor/acceptor. The pH optimum was at pH 8, and the temperature optimum at 45 °C. Highest specific activities were observed for reduction of C 3 - C 5 -aldehydes with NADH, such as propanal to propanol (380 ± 15 mU mg -1 protein), butanal to butanol (300 ± 24 mU mg -1 ), and 3-hydroxybutanal to 1,3-butanediol (248 ± 60 mU mg -1 ), however, the enzyme also oxidized 3-hydroxybutanal with NAD + to acetoacetaldehyde (83 ± 18 mU mg -1 ). The enzyme might play a key role in acetone degradation by D. biacutus, for example as a bifunctional 3-hydroxybutanal dehydrogenase/reductase. Its recombinant production may represent an important step in the elucidation of the complete degradation pathway.

  2. Synchrotron radiation and free electron laser activities in Novosibirsk

    International Nuclear Information System (INIS)

    Korchuganov, V.N.; Kulipanov, G.N.; Mezentsev, N.A.; Oreshkov, A.D.; Panchenko, V.E.; Pindyurin, V.F.; Skrinskij, A.N.; Sheromov, M.A.; Vinokurov, N.A.; Zolotarev, K.V.

    1994-01-01

    The results of studies realized in the Siberian synchrotron radiation centre within the frameworks of wide program of synchrotron radiation and free electron laser research are summarized. The technical information on the VEPP-2M, VEPP-3 and VEPP-4M storage rings used as synchrotron radiation sources is given. 10 refs.; 8 figs.; 12 tabs

  3. Beyond usage: understanding the use of electronic journals on the basis of information activity analysis. Electronic journals, Use studies, Information activity, Scientific communication

    Directory of Open Access Journals (Sweden)

    Annaïg Mahé

    2004-01-01

    Full Text Available In this article, which reports the second part of a two-part study of the use of electronic journals by researchers in two French research institutions, we attempt to explain the integration of the use of electronic journals in the scientists' information habits, going beyond usage analysis. First, we describe how the development of electronic journals use follows a three-phase innovation process - research-development, first uses, and technical acculturation. Then, we attempt to find more significant explanatory factors, and emphasis is placed on the wider context of information activity. Three main information activity types are outlined - marginal, parallel, and integrated. Each of these types corresponds to a particular attitude towards scientific information and to different levels of electronic journal use.

  4. Site-Specific Bioconjugation of an Organometallic Electron Mediator to an Enzyme with Retained Photocatalytic Cofactor Regenerating Capacity and Enzymatic Activity

    Directory of Open Access Journals (Sweden)

    Sung In Lim

    2015-04-01

    Full Text Available Photosynthesis consists of a series of reactions catalyzed by redox enzymes to synthesize carbohydrates using solar energy. In order to take the advantage of solar energy, many researchers have investigated artificial photosynthesis systems mimicking the natural photosynthetic enzymatic redox reactions. These redox reactions usually require cofactors, which due to their high cost become a key issue when constructing an artificial photosynthesis system. Combining a photosensitizer and an Rh-based electron mediator (RhM has been shown to photocatalytically regenerate cofactors. However, maintaining the high concentration of cofactors available for efficient enzymatic reactions requires a high concentration of the expensive RhM; making this process cost prohibitive. We hypothesized that conjugation of an electron mediator to a redox enzyme will reduce the amount of electron mediators necessary for efficient enzymatic reactions. This is due to photocatalytically regenerated NAD(PH being readily available to a redox enzyme, when the local NAD(PH concentration near the enzyme becomes higher. However, conventional random conjugation of RhM to a redox enzyme will likely lead to a substantial loss of cofactor regenerating capacity and enzymatic activity. In order to avoid this issue, we investigated whether bioconjugation of RhM to a permissive site of a redox enzyme retains cofactor regenerating capacity and enzymatic activity. As a model system, a RhM was conjugated to a redox enzyme, formate dehydrogenase obtained from Thiobacillus sp. KNK65MA (TsFDH. A RhM-containing azide group was site-specifically conjugated to p-azidophenylalanine introduced to a permissive site of TsFDH via a bioorthogonal strain-promoted azide-alkyne cycloaddition and an appropriate linker. The TsFDH-RhM conjugate exhibited retained cofactor regenerating capacity and enzymatic activity.

  5. Aloe vera in active and passive regions of electronic devices towards a sustainable development

    Science.gov (United States)

    Lim, Zhe Xi; Sreenivasan, Sasidharan; Wong, Yew Hoong; Cheong, Kuan Yew

    2017-07-01

    The increasing awareness towards sustainable development of electronics has driven the search for natural bio-organic materials in place of conventional electronic materials. The concept of using natural bio-organic materials in electronics provides not only an effective solution to address global electronic waste crisis, but also a compelling template for sustainable electronics manufacturing. This paper attempts to provide an overview of using Aloe vera gel as a natural bio-organic material for various electronic applications. Important concepts such as responses of living Aloe vera plant towards electrical stimuli and demonstrations of Aloe vera films as passive and active regions of electronic devices are highlighted in chronological order. The biodegradability and biocompatibility of Aloe vera can bring the world a step closer towards the ultimate goal of sustainable development of electronic devices from "all-natural" materials.

  6. Pyruvate Dehydrogenase and Pyruvate Dehydrogenase Kinase Expression in Non Small Cell Lung Cancer and Tumor-Associated Stroma

    Directory of Open Access Journals (Sweden)

    Michael I. Koukourakis

    2005-01-01

    Full Text Available Pyruvate dehydrogenase (PDH catalyzes the conversion of pyruvate to acetyl-coenzyme A, which enters into the Krebs cycle, providing adenosine triphosphate (ATP to the cell. PDH activity is under the control of pyruvate dehydrogenase kinases (PDKs. Under hypoxic conditions, conversion of pyruvate to lactate occurs, a reaction catalyzed by lactate dehydrogenase 5 (LDH5. In cancer cells, however, pyruvate is transformed to lactate occurs, regardless of the presence of oxygen (aerobic glycolysis/Warburg effect. Although hypoxic intratumoral conditions account for HIFia stabilization and induction of anaerobic metabolism, recent data suggest that high pyruvate concentrations also result in HIFia stabilization independently of hypoxia. In the present immunohistochemical study, we provide evidence that the PDH/PDK pathway is repressed in 73% of non small cell lung carcinomas, which may be a key reason for HIFia stabilization and “aerobic glycolysis.” However, about half of PDHdeficient carcinomas are not able to switch on the HIF pathway, and patients harboring these tumors have an excellent postoperative outcome. A small subgroup of clinically aggressive tumors maintains a coherent PDH and HIF/LDH5 expression. In contrast to cancer cells, fibroblasts in the tumor-supporting stroma exhibit an intense PDH but reduced PDK1 expression favoring maximum PDH activity. This means that stroma may use lactic acid produced by tumor cells, preventing the creation of an intolerable intratumoral acidic environment at the same time.

  7. A Cytochemical Study of the Dehydrogenases of Mitochondria and Mitochondrial Particulates by a Monotetrazolium-Cobalt Chelation Method

    Science.gov (United States)

    Pearse, A. G. E.; Scarpelli, D. G.; Hess, R.

    1960-01-01

    In one of the current histochemical methods for dehydrogenases and diaphorases the final product is a metal-formazan dye derived from reduction of an N-thiazolyl-substituted tetrazolium. Sites of enzymic activity consistently appear as intramitochondrial dots 0.2 to 0.3 µ in diameter. When applied to active particles from disrupted mitochondria (Keilin-Hartree preparation, electron transport particle, Cooper-Lehninger particle) the individual particles appear as black dots 0.1 to 0.3 µ in diameter. It is clear that formazan is deposited progressively upon the particles and the results suggest that the latter may be spatially arranged in mitochondria so that areas of activity are separated by quiescent regions. PMID:14431240

  8. Defects in the Expression of Chloroplast Proteins Leads to H2O2 Accumulation and Activation of Cyclic Electron Flow around Photosystem I.

    Science.gov (United States)

    Strand, Deserah D; Livingston, Aaron K; Satoh-Cruz, Mio; Koepke, Tyson; Enlow, Heather M; Fisher, Nicholas; Froehlich, John E; Cruz, Jeffrey A; Minhas, Deepika; Hixson, Kim K; Kohzuma, Kaori; Lipton, Mary; Dhingra, Amit; Kramer, David M

    2016-01-01

    We describe a new member of the class of mutants in Arabidopsis exhibiting high rates of cyclic electron flow around photosystem I (CEF), a light-driven process that produces ATP but not NADPH. High cyclic electron flow 2 ( hcef2 ) shows strongly increased CEF activity through the NADPH dehydrogenase complex (NDH), accompanied by increases in thylakoid proton motive force ( pmf ), activation of the photoprotective q E response, and the accumulation of H 2 O 2 . Surprisingly, hcef2 was mapped to a non-sense mutation in the TADA1 (tRNA adenosine deaminase arginine) locus, coding for a plastid targeted tRNA editing enzyme required for efficient codon recognition. Comparison of protein content from representative thylakoid complexes, the cytochrome bf complex, and the ATP synthase, suggests that inefficient translation of hcef2 leads to compromised complex assembly or stability leading to alterations in stoichiometries of major thylakoid complexes as well as their constituent subunits. Altered subunit stoichiometries for photosystem I, ratios and properties of cytochrome bf hemes, and the decay kinetics of the flash-induced thylakoid electric field suggest that these defect lead to accumulation of H 2 O 2 in hcef2 , which we have previously shown leads to activation of NDH-related CEF. We observed similar increases in CEF, as well as increases in H 2 O 2 accumulation, in other translation defective mutants. This suggests that loss of coordination in plastid protein levels lead to imbalances in photosynthetic energy balance that leads to an increase in CEF. These results taken together with a large body of previous observations, support a general model in which processes that lead to imbalances in chloroplast energetics result in the production of H 2 O 2 , which in turn activates CEF. This activation could be from either H 2 O 2 acting as a redox signal, or by a secondary effect from H 2 O 2 inducing a deficit in ATP.

  9. The use of triphenyltetrazolium chloride in the study of dehydrogenase activity of Brucellae O emprêgo do cloreto de trifeniltetrazólio no estudo da atividade dehidrogenásica de brucelas

    Directory of Open Access Journals (Sweden)

    Milton Thiago de Mello

    1955-05-01

    Full Text Available Experiments for the investigation of dehydrogenase activity of washed cells of a strains of Br. abortus and another of Br. suis in presence of different single added substrates are reported. The activity was measured as the amount of formazan produced by the reduction of 2, 3, 5-triphenyltetrazolum chloride acting as a hydrogen ions acceptor, at pH 7.0. In a general manner the dehydrogenase activity of Br. suis was much more intense than that of Br. abortus (fig. 5. In the conditions of the experiments Br. abortus oxidized L-arabinose, D-galactose, D-glucose, glycerol, D-xylose, DL-alanine, D-fructose, and D-sorbitol. Brucella suis oxidized D-xylose, L-arabinose, D-glucose, D-galactose, DL-alanine, sodium acetate, maltose, glycine, D-fructose, and D-sorbitol. Glycerol was oxidized by Br. abortus but its oxidation by Br. suir was very slight. Sodium acetate and maltose were intensely oxidized by Br. suir but not by Br. abortus. The sites of more intense enzymatic acitivity were seen as small red colored round granules located in one pole of the cells.Com a finalidade de observar a atividade dhidrogenásica de brucelas, em presença de diversos substratos isolados, empregamos o cloreto de trifeniltetrazólio (em solução aquosa a 0,1% como receptor de hidrogênio. Os substratos (em solução aquosa M 50 foram os seguintes: Hidratos de carbono: L-arabinose, D-frutose, D-galactose, D-glucose, D-lactose, matose e D-xilose; alcoóis: glicerol, L-inositol, D-manitol e D-sobitol; ácidos aminados: ácido D-glutâmico, D-arginina, DL-alanina, L-asparagina e glicina; acetato de sódio. Empregamos suspensões de culturas de 48 horas de duas amostras típicas: Brucella abortus (aeróbica, nº 1 868, amostra B-99, Weybridge e Br. suis (nº 1 568, amostra SIG do Dr. S. S. Elberg, da Universidade de Califórnia. As culturas em agar, lavadas 5 vêzes em solução de cloreto de sódio a 0,9% ("resting cells" foram suspensas nessas solução salina de maneira a

  10. Topology Optimization of an Actively Cooled Electronics Section for Downhole Tools

    DEFF Research Database (Denmark)

    Soprani, Stefano; Klaas Haertel, Jan Hendrik; Lazarov, Boyan Stefanov

    2015-01-01

    Active cooling systems represent a possible solution to the electronics overheating that occurs in wireline downhole tools operating in high temperature oil and gas wells. A Peltier cooler was chosen to maintain the downhole electronics to a tolerable temperature, but its integration into the dow......Active cooling systems represent a possible solution to the electronics overheating that occurs in wireline downhole tools operating in high temperature oil and gas wells. A Peltier cooler was chosen to maintain the downhole electronics to a tolerable temperature, but its integration......, according to the topology optimization results and assembly constraints, and compared to the optimized cases....

  11. Glucose 6 phosphate dehydrogenase deficiency in adults

    International Nuclear Information System (INIS)

    Khan, M.

    2004-01-01

    Objective: To determine the frequency of glucose-6-phosphate dehydrogenase (G6PD) deficiency in adults presented with anemia. Subjects and Methods: Eighteen months admission data was reviewed for G6PD deficiency as a cause of anemia. Anemia was defined by world health organization (WHO) criteria as haemoglobin less than 11.3 gm%. G6PD activity was measured by Sigma dye decolorisation method. All patients were screened for complications of hemolysis and its possible cause. Patients with more than 13 years of age were included in the study. Results: Out of 3600 patients admitted, 1440 were found anaemic and 49 as G6PD deficient. So the frequency of G6PD deficiency in anaemic patients was 3.4% and the overall frequency is 1.36%. G6PD deficiency among males and females was three and six percent respectively. Antimalarials and antibiotics containing sulphonamide group were the most common precipitating factors for hemolysis. Anemia and jaundice were the most common presentations while malaria was the most common associated disease. Acute renal failure was the most severe complication occurring in five patients with two deaths. Conclusion: G6PD deficiency is a fairly common cause of anemia with medicine as common precipitating factor for hemolysis. Such complications can be avoided with early recognition of the disease and avoiding indiscriminate use of medicine. (author)

  12. Atividade da catalase e da lactato desidrogenase em tilápias submetidas a estresse de confinamento: efeito da cor do ambiente Catalase and lactate dehydrogenase activity in tilapia subjected to contention stress: effect of the background color

    Directory of Open Access Journals (Sweden)

    Elyara Maria Pereira-da-Silva

    2012-05-01

    Full Text Available Avaliaram-se os efeitos da cor do ambiente sobre o crescimento e a atividade da enzima antioxidante catalase (CAT e da lactato desidrogenase (LDH em tilápias do Nilo (n=24; 36,2±3,6g. Oito exemplares foram mortos para determinação da atividade basal das enzimas e os demais permaneceram isolados durante 14 dias sob espectro de luz branca ou azul (n=8 peixes/tratamento. A seguir os peixes foram submetidos a um estresse diário de confinamento de 90 minutos (15° ao 28° dia e pesados semanalmente para cálculo da taxa de crescimento específico (TCE. A TCE negativa confirmou que o confinamento provocou estresse nos peixes, independentemente da cor do ambiente. O aumento da atividade da LDH no músculo vermelho dos peixes mantidos sob luz branca ou azul indicou mudança do metabolismo aeróbio para anaeróbio. O estresse reduziu a atividade da CAT no músculo branco dos peixes mantidos sob a luz branca ou azul. Na musculatura vermelha, esta redução ocorreu apenas nos animais mantidos sob a luz branca. O confinamento aumenta os processos metabólicos anaeróbios e é adequado para estudos sobre os efeitos do estresse. O espectro de luz azul não evita a redução do crescimento e a demanda energética anaeróbia em situações de estresse, mas preserva a atividade da CAT, contribuindo para o bem-estar da tilápia.We assess the effects of the background color on the growth and antioxidant enzyme catalase (CAT and lactate dehydrogenase (LDH in Nile tilapia (n=24; 36.2±3.6g. Eight fish were killed for assessment of basal activity of the enzymes and the others remained isolated for 14 days under white or blue light spectrum (n=8 fish/treatment. Then each animal were subjected to a daily stress of confinement of 90 minutes (15th to 28th day and weighed to calculate the specific growth rate (SGR. The negative SGR confirmed that the confinement stressed in fish, regardless of the background color. The increased activity of LDH in red muscle of fish

  13. Highly Stable l-Lysine 6-Dehydrogenase from the Thermophile Geobacillus stearothermophilus Isolated from a Japanese Hot Spring: Characterization, Gene Cloning and Sequencing, and Expression

    Science.gov (United States)

    Heydari, Mojgan; Ohshima, Toshihisa; Nunoura-Kominato, Naoki; Sakuraba, Haruhiko

    2004-01-01

    l-Lysine dehydrogenase, which catalyzes the oxidative deamination of l-lysine in the presence of NAD, was found in the thermophilic bacterium Geobacillus stearothermophilus UTB 1103 and then purified about 3,040-fold from a crude extract of the organism by using four successive column chromatography steps. This is the first report showing the presence of a thermophilic NAD-dependent lysine dehydrogenase. The product of the enzyme catalytic activity was determined to be Δ1-piperideine-6-carboxylate, indicating that the enzyme is l-lysine 6-dehydrogenase (LysDH) (EC 1.4.1.18). The molecular mass of the purified protein was about 260 kDa, and the molecule was determined to be a homohexamer with subunit molecular mass of about 43 kDa. The optimum pH and temperature for the catalytic activity of the enzyme were about 10.1 and 70°C, respectively. No activity was lost at temperatures up to 65°C in the presence of 5 mM l-lysine. The enzyme was relatively selective for l-lysine as the electron donor, and either NAD or NADP could serve as the electron acceptor (NADP exhibited about 22% of the activity of NAD). The Km values for l-lysine, NAD, and NADP at 50°C and pH 10.0 were 0.73, 0.088, and 0.48 mM, respectively. When the gene encoding this LysDH was cloned and overexpressed in Escherichia coli, a crude extract of the recombinant cells had about 800-fold-higher enzyme activity than the extract of G. stearothermophilus. The nucleotide sequence of the LysDH gene encoded a peptide containing 385 amino acids with a calculated molecular mass of 42,239 Da. PMID:14766574

  14. Characterization of human short chain dehydrogenase/reductase SDR16C family members related to retinol dehydrogenase 10.

    Science.gov (United States)

    Adams, Mark K; Lee, Seung-Ah; Belyaeva, Olga V; Wu, Lizhi; Kedishvili, Natalia Y

    2017-10-01

    All-trans-retinoic acid (RA) is a bioactive derivative of vitamin A that serves as an activating ligand for nuclear transcription factors, retinoic acid receptors. RA biosynthesis is initiated by the enzymes that oxidize retinol to retinaldehyde. It is well established that retinol dehydrogenase 10 (RDH10, SDR16C4), which belongs to the 16C family of the short chain dehydrogenase/reductase (SDR) superfamily of proteins, is the major enzyme responsible for the oxidation of retinol to retinaldehyde for RA biosynthesis during embryogenesis. However, several lines of evidence point towards the existence of additional retinol dehydrogenases that contribute to RA biosynthesis in vivo. In close proximity to RDH10 gene on human chromosome 8 are located two genes that are phylogenetically related to RDH10. The predicted protein products of these genes, retinol dehydrogenase epidermal 2 (RDHE2, SDR16C5) and retinol dehydrogenase epidermal 2-similar (RDHE2S, SDR16C6), share 59% and 56% sequence similarity with RDH10, respectively. Previously, we showed that the single ortholog of the human RDHE2 and RDHE2S in frogs, Xenopus laevis rdhe2, oxidizes retinol to retinaldehyde and is essential for frog embryonic development. In this study, we explored the potential of each of the two human proteins to contribute to RA biosynthesis. The results of this study demonstrate that human RDHE2 exhibits a relatively low but reproducible activity when expressed in either HepG2 or HEK293 cells. Expression of the native RDHE2 is downregulated in the presence of elevated levels of RA. On the other hand, the protein encoded by the human RDHE2S gene is unstable when expressed in HEK293 cells. RDHE2S protein produced in Sf9 cells is stable but has no detectable catalytic activity towards retinol. We conclude that the human RDHE2S does not contribute to RA biosynthesis, whereas the low-activity RA-sensitive human RDHE2 may have a role in adjusting the cellular levels of RA in accord with

  15. Structural and kinetic basis for substrate selectivity in Populus tremuloides sinapyl alcohol dehydrogenase.

    Science.gov (United States)

    Bomati, Erin K; Noel, Joseph P

    2005-05-01

    We describe the three-dimensional structure of sinapyl alcohol dehydrogenase (SAD) from Populus tremuloides (aspen), a member of the NADP(H)-dependent dehydrogenase family that catalyzes the last reductive step in the formation of monolignols. The active site topology revealed by the crystal structure substantiates kinetic results indicating that SAD maintains highest specificity for the substrate sinapaldehyde. We also report substantial substrate inhibition kinetics for the SAD-catalyzed reduction of hydroxycinnamaldehydes. Although SAD and classical cinnamyl alcohol dehydrogenases (CADs) catalyze the same reaction and share some sequence identity, the active site topology of SAD is strikingly different from that predicted for classical CADs. Kinetic analyses of wild-type SAD and several active site mutants demonstrate the complexity of defining determinants of substrate specificity in these enzymes. These results, along with a phylogenetic analysis, support the inclusion of SAD in a plant alcohol dehydrogenase subfamily that includes cinnamaldehyde and benzaldehyde dehydrogenases. We used the SAD three-dimensional structure to model several of these SAD-like enzymes, and although their active site topologies largely mirror that of SAD, we describe a correlation between substrate specificity and amino acid substitution patterns in their active sites. The SAD structure thus provides a framework for understanding substrate specificity in this family of enzymes and for engineering new enzyme specificities.

  16. Defects in the Expression of Chloroplast Proteins Leads to H2O2 Accumulation and Activation of Cyclic Electron Flow around Photosystem I

    Energy Technology Data Exchange (ETDEWEB)

    Strand, Deserah D.; Livingston, Aaron K.; Satoh-Cruz, Mio; Koepke, Tyson; Enlow, Heather M.; Fisher, Nicholas; Froehlich, John E.; Cruz, Jeffrey A.; Minhas, Deepika; Hixson, Kim K.; Kohzuma, Kaori; Lipton, Mary; Dhingra, Amit; Kramer, David M.

    2017-01-13

    We describe a new member of the class of mutants in Arabidopsis exhibiting high rates of cyclic electron flow around photosystem I (CEF), a light-driven process that produces ATP but not NADPH. High cyclic electron flow 2 (hcef2) shows strongly increased CEF activity through the NADPH dehydrogenase complex (NDH), accompanied by increases in thylakoid proton motive force (pmf), activation of the photoprotective qE response, and the accumulation of H2O2 . Surprisingly, hcef2 was mapped to a nonsense mutation in the TADA1 (tRNA adenosine deaminase arginine) locus, coding for a plastid targeted tRNA editing enzyme required for efficient codon recognition. Comparison of protein content from representative thylakoid complexes, the cytochrome bf complex and the ATP synthase, suggests that inefficient translation of hcef2 leads to compromised complex assembly or stability leading to alterations in stoichiometries of major thylakoid complexes as well as their constituent subunits. Altered subunit stoichiometries for photosystem I, ratios and properties of cytochrome bf hemes, and the decay kinetics of the flash induced thylakoid electric field suggest that these defect lead to accumulation of H2O2 in hcef2, which we have previously shown leads to activation of NDHrelated CEF. We observed similar increases in CEF and H2O2 accumulation in other translation defective mutants, suggesting that loss of coordination in plastid protein levels lead to imbalances in the photosynthetic energy balance that leads to increased CEF. These results, together with a large body of previous observations, support a general model in which processes that imbalances in chloroplast energetics result in the production of H2O2 , which activates CEF, either as a redox signal or by inducing deficits in ATP levels.

  17. Oxide-cathode activation and surface temperature calculation of electron cooler

    International Nuclear Information System (INIS)

    Li Jie; Yang Xiaodong; Mao Lijun; Li Guohong; Yuan Youjin; Liu Zhanwen; Zhang Junhui; Yang Xiaotian; Ma Xiaoming; Yan Tailai

    2011-01-01

    The pollution on electron gun ceramic insulation of electron cooler restricted the operation of electron cooler at HIRFL-CSR main ring. To cool and accumulate ion beam well, the pollution was cleared and a new oxide-coated cathode was assembled. The processes of cathode replacement,vacuum chamber baking-out, and thermal decomposition of coating binders and alkaline earth metal carbonates, and cathode activation are presented. The electron gun perveance of 10.6 μA/V 1.5 was attained under the heating power of 60 W. The typical surface temperature of oxide-coated cathode that is calculated through grey-body radiation is 1 108 K which shows a comparable result to the experimental measurement 1 078 K. The perveance growth of electron gun during the electron cooler operation is also explained by partial activation of the cathode. (authors)

  18. Study on Effects of Electron Donors on Phosphine Production from Anaerobic Activated Sludge

    Directory of Open Access Journals (Sweden)

    Jianping Cao

    2017-07-01

    Full Text Available The effects of different types and concentrations of electron donors (glucose, starch, methanol and sodium acetate on the formation of phosphine from anaerobic activated sludge that has been domesticated for a prolonged period were studied in small batch experiments. The results show that types and concentrations of electron donor have significant effects on the production of phosphine from anaerobic activated sludge. Among them, glucose was the most favourable electron donor, whereas sodium acetate was the least favourable electron donor for the removal of phosphorus and the production of phosphine. Higher concentrations of electron donors were more favourable for the reduction of phosphate into phosphine, and supplying more than nine times the amount of electron donor as theoretically required for the reduction of phosphate into phosphine was favourable for the production of phosphine.

  19. Stable aqueous dispersions of optically and electronically active phosphorene.

    Science.gov (United States)

    Kang, Joohoon; Wells, Spencer A; Wood, Joshua D; Lee, Jae-Hyeok; Liu, Xiaolong; Ryder, Christopher R; Zhu, Jian; Guest, Jeffrey R; Husko, Chad A; Hersam, Mark C

    2016-10-18

    Understanding and exploiting the remarkable optical and electronic properties of phosphorene require mass production methods that avoid chemical degradation. Although solution-based strategies have been developed for scalable exfoliation of black phosphorus, these techniques have thus far used anhydrous organic solvents in an effort to minimize exposure to known oxidants, but at the cost of limited exfoliation yield and flake size distribution. Here, we present an alternative phosphorene production method based on surfactant-assisted exfoliation and postprocessing of black phosphorus in deoxygenated water. From comprehensive microscopic and spectroscopic analysis, this approach is shown to yield phosphorene dispersions that are stable, highly concentrated, and comparable to micromechanically exfoliated phosphorene in structure and chemistry. Due to the high exfoliation efficiency of this process, the resulting phosphorene flakes are thinner than anhydrous organic solvent dispersions, thus allowing the observation of layer-dependent photoluminescence down to the monolayer limit. Furthermore, to demonstrate preservation of electronic properties following solution processing, the aqueous-exfoliated phosphorene flakes are used in field-effect transistors with high drive currents and current modulation ratios. Overall, this method enables the isolation and mass production of few-layer phosphorene, which will accelerate ongoing efforts to realize a diverse range of phosphorene-based applications.

  20. The Alcohol Dehydrogenase Isoenzyme as a Potential Marker of Pancreatitis.

    Science.gov (United States)

    Jelski, Wojciech; Piechota, Joanna; Orywal, Karolina; Szmitkowski, Maciej

    2018-05-01

    Human pancreas parenchyma contains various alcohol dehydrogenase (ADH) isoenzymes and also possesses aldehyde dehydrogenase (ALDH) activity. The altered activities of ADH and ALDH in damaged pancreatic tissue in the course of pancreatitis are reflected in the human serum. The aim of this study was to investigate a potential role of ADH and ALDH as markers for acute (AP) and chronic pancreatitis (CP). Serum samples were collected for routine biochemical investigations from 75 patients suffering from acute pancreatitis and 70 patients with chronic pancreatitis. Fluorometric methods were used to measure the activity of class I and II ADH and ALDH activity. The total ADH activity and activity of class III and IV isoenzymes were measured by a photometric method. There was a significant increase in the activity of ADH III isoenzyme (15.06 mU/l and 14.62 mU/l vs. 11.82 mU/l; ppancreatitis or chronic pancreatitis compared to the control. The diagnostic sensitivity for ADH III was about 84%, specificity was 92 %, positive and negative predictive values were 93% and 87% respectively in acute pancreatitis. Area under the Receiver Operating Curve (ROC) curve for ADH III in AP and CP was 0.88 and 0.86 respectively. ADH III has a potential role as a marker of acute and chronic pancreatitis. Copyright© 2018, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  1. CMOS Active Pixel Sensor Star Tracker with Regional Electronic Shutter

    Science.gov (United States)

    Yadid-Pecht, Orly; Pain, Bedabrata; Staller, Craig; Clark, Christopher; Fossum, Eric

    1996-01-01

    The guidance system in a spacecraft determines spacecraft attitude by matching an observed star field to a star catalog....An APS(active pixel sensor)-based system can reduce mass and power consumption and radiation effects compared to a CCD(charge-coupled device)-based system...This paper reports an APS (active pixel sensor) with locally variable times, achieved through individual pixel reset (IPR).

  2. Textural and electronic characteristics of mechanochemically activated composites with nanosilica and activated carbon

    International Nuclear Information System (INIS)

    Gun’ko, V.M.; Zaulychnyy, Ya.V.; Ilkiv, B.I.; Zarko, V.I.; Nychiporuk, Yu.M.; Pakhlov, E.M.; Ptushinskii, Yu.G.; Leboda, R.; Skubiszewska-Zięba, J.

    2011-01-01

    Nanosilicas (A-50, A-300, A-500)/activated carbon (AC, S BET = 1520 m 2 /g) composites were prepared using short-term (5 min) mechanochemical activation (MCA) of powder mixtures in a microbreaker. Smaller silica nanoparticles of A-500 (average diameter d av = 5.5 nm) can more easily penetrate into broad mesopores and macropores of AC microparticles than larger nanoparticles of A-50 (d av = 52.4 nm) or A-300 (d av = 8.1 nm). After MCA of silica/AC, nanopores of non-broken AC nanoparticles remained accessible for adsorbed N 2 molecules. According to ultra-soft X-ray emission spectra (USXES), MCA of silica/AC caused formation of chemical bonds Si-O-C; however, Si-C and Si-Si bonds were practically not formed. A decrease in intensity of OK α band in respect to CK α band of silica/AC composites with diminishing sizes of silica nanoparticles is due to both changes in the surface structure of particles and penetration of a greater number of silica nanoparticles into broad pores of AC microparticles and restriction of penetration depth of exciting electron beam into the AC particles.

  3. Alcohol dehydrogenase of acetic acid bacteria: structure, mode of action, and applications in biotechnology.

    Science.gov (United States)

    Yakushi, Toshiharu; Matsushita, Kazunobu

    2010-05-01

    Pyrroquinoline quinone-dependent alcohol dehydrogenase (PQQ-ADH) of acetic acid bacteria is a membrane-bound enzyme involved in the acetic acid fermentation by oxidizing ethanol to acetaldehyde coupling with reduction of membranous ubiquinone (Q), which is, in turn, re-oxidized by ubiquinol oxidase, reducing oxygen to water. PQQ-ADHs seem to have co-evolved with the organisms fitting to their own habitats. The enzyme consists of three subunits and has a pyrroloquinoline quinone, 4 heme c moieties, and a tightly bound Q as the electron transfer mediators. Biochemical, genetic, and electrochemical studies have revealed the unique properties of PQQ-ADH since it was purified in 1978. The enzyme is unique to have ubiquinol oxidation activity in addition to Q reduction. This mini-review focuses on the molecular properties of PQQ-ADH, such as the roles of the subunits and the cofactors, particularly in intramolecular electron transport of the enzyme from ethanol to Q. Also, we summarize biotechnological applications of PQQ-ADH as to enantiospecific oxidations for production of the valuable chemicals and bioelectrocatalysis for sensors and fuel cells using indirect and direct electron transfer technologies and discuss unsolved issues and future prospects related to this elaborate enzyme.

  4. Effective immobilization of alcohol dehydrogenase on carbon nanoscaffolds for ethanol biofuel cell.

    Science.gov (United States)

    Umasankar, Yogeswaran; Adhikari, Bal-Ram; Chen, Aicheng

    2017-12-01

    An efficient approach for immobilizing alcohol dehydrogenase (ADH) while enhancing its electron transfer ability has been developed using poly(2-(trimethylamino)ethyl methacrylate) (MADQUAT) cationic polymer and carbon nanoscaffolds. The carbon nanoscaffolds were comprised of single-walled carbon nanotubes (SWCNTs) wrapped with reduced graphene oxide (rGO). The ADH entrapped within the MADQUAT that was present on the carbon nanoscaffolds exhibited a high electron exchange capability with the electrode through its cofactor β-nicotinamide adenine dinucleotide hydrate and β-nicotinamide adenine dinucleotide reduced disodium salt hydrate (NAD + /NADH) redox reaction. The advantages of the carbon nanoscaffolds used as the support matrix and the MADQUAT employed for the entrapment of ADH versus physisorption were demonstrated via cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Our experimental results showed a higher electron transfer, electrocatalytic activity, and rate constant for MADQUAT entrapped ADH on the carbon nanoscaffolds. The immobilization of ADH using both MADQUAT and carbon nanoscaffolds exhibited strong potential for the development of an efficient bio-anode for ethanol powered biofuel cells. Copyright © 2017 Elsevier B.V. All rights reserved.

  5. Magnetic nanoparticle imaging using multiple electron paramagnetic resonance activation sequences

    International Nuclear Information System (INIS)

    Coene, A.; Dupré, L.; Crevecoeur, G.

    2015-01-01

    Magnetic nanoparticles play an important role in several biomedical applications such as hyperthermia, drug targeting, and disease detection. To realize an effective working of these applications, the spatial distribution of the particles needs to be accurately known, in a non-invasive way. Electron Paramagnetic Resonance (EPR) is a promising and sensitive measurement technique for recovering these distributions. In the conventional approach, EPR is applied with a homogeneous magnetic field. In this paper, we employ different heterogeneous magnetic fields that allow to stabilize the solution of the associated inverse problem and to obtain localized spatial information. A comparison is made between the two approaches and our novel adaptation shows an average increase in reconstruction quality by 5% and is 12 times more robust towards noise. Furthermore, our approach allows to speed up the EPR measurements while still obtaining reconstructions with an improved accuracy and noise robustness compared to homogeneous EPR

  6. New developments in radiation protection instrumentation via active electronic methods

    International Nuclear Information System (INIS)

    Umbarger, C.J.

    1981-01-01

    New developments in electronics and radiation detectors are improving on real-time data acquisition of radiation exposure and contamination conditions. Recent developments in low power circuit designs, hybrid and integrated circuits, and microcomputers have all contributed to smaller and lighter radiation detection instruments that are, at the same time, more sensitive and provide more information (e.g., radioisotope identification) than previous devices. New developments in radiation detectors, such as cadmium telluride, gas scintillation proportional counters, and imaging counters (both charged particle and photon) promise higher sensitivities and expanded uses over present instruments. These developments are being applied in such areas as health physics, waste management, environmental monitoring, in vivo measurements, and nuclear safeguards

  7. Electron Tomography Reveals the Active Phase–Support Interaction in Sulfidic Hydroprocessing Catalysts

    NARCIS (Netherlands)

    Eijsbouts, Sonja; Li, Xuang; Juan-Alcaniz, Jana; van den Oetelaar, Leon C A; Bergwerff, Jaap; Loos, Joachim; Carlsson, Anna; Vogt, E.T.C.

    2017-01-01

    Conventional two-dimensional (2D) transmission electron microscopy of sulfidic hydroprocessing catalysts can be deceiving and give the impression that parts of the support are overloaded with active phase. High-angle annular dark field scanning transmission electron microscopy tomography reveals

  8. Metal-Organic Frameworks as Active Materials in Electronic Sensor Devices.

    Science.gov (United States)

    Campbell, Michael G; Dincă, Mircea

    2017-05-12

    In the past decade, advances in electrically conductive metal-organic frameworks (MOFs) and MOF-based electronic devices have created new opportunities for the development of next-generation sensors. Here we review this rapidly-growing field, with a focus on the different types of device configurations that have allowed for the use of MOFs as active components of electronic sensor devices.

  9. Radiation target analyses of free and immobilized glucose 6-phosphate dehydrogenase

    International Nuclear Information System (INIS)

    Kempner, E.S.; Miller, J.H.

    2010-01-01

    The sensitivity of the enzyme glucose 6-phosphate dehydrogenase to ionizing radiation was examined under several conditions, including the presence of several free-radical scavengers. The enzyme was also irradiated when covalently bound to polyacrylamide beads whose structure is very similar to the polypeptide backbone of proteins. All the enzyme forms were irradiated in the frozen state with high-energy electrons from a linear accelerator. Surviving enzyme activity and surviving monomers were determined; the data were analyzed by target theory. Free-radical scavengers reduced the radiation target size of both the activity and monomers of the free enzyme, but not that of the immobilized enzyme activity. The target size of the activity of the free enzyme was that of a dimer mass, but in the case of the immobilized enzyme it was equal to the smaller mass of the monomer. Free-radical scavengers reduce the target size by modifying radiation energy transfer. The target size of the polyacrylamide-bound enzyme activity was expected to be very large since the connection between polyacrylamide and protein is a peptide bond which permits transfer of radiation-deposited energy. Several explanations concerning energy transfer are suggested for this result.

  10. Surface and interface electronic structure: Three year activity report

    International Nuclear Information System (INIS)

    Kevan, S.D.

    1992-01-01

    The 3-year activity report covers surface structure and phonon anomalies (surface reconstruction on W(001) and Mo(001), adsorbate lateral ordering, surface Fermi contours and phonon anomalies on Pt(111) and Pd(001)), adsorbate vibrational damping, charge transfer in momentum space: W(011)-K, surface states and resonances (relativistic effects ampersand computations, surface resonances)

  11. Promoting direct interspecies electron transfer with activated carbon

    DEFF Research Database (Denmark)

    Liu, Fanghua; Rotaru, Amelia-Elena; Shrestha, Pravin M.

    2012-01-01

    Granular activated carbon (GAC) is added to methanogenic digesters to enhance conversion of wastes to methane, but the mechanism(s) for GAC’s stimulatory effect are poorly understood. GAC has high electrical conductivity and thus it was hypothesized that one mechanism for GAC stimulation...

  12. Determinação das atividades séricas de creatina quinase, lactato desidrogenase e aspartato aminotransferase em eqüinos de diferentes categorias de atividade Determination of serum activities of creatine kinase, lactate dehydrogenase, and aspartate aminotransferase in horses of different activities classes

    Directory of Open Access Journals (Sweden)

    I.A. Câmara e Silva

    2007-02-01

    Full Text Available The creatine kinase (CK, lactate dehydrogenase (LDH, and aspartate aminotransferase (AST seric activities in horses of different activity classes (athlete, traction, and reproduction, were compared. Fifty-eight horses were alloted into three groups - group 1 with 20 athletes, "vaquejada" competitors; group 2 with 20 breeding horses; and group 3 with 18 draft horses, averaging 10 working hours daily. The average values for CK serum activity were 80.2, 83.9, and 94.4 U/l in groups 1, 2, and 3, respectively. Result of group 3 was significantly different from the other groups. The averages values for LDH were 102.5, 98.6, and 112.8 U/l in groups 1, 2, and 3, respectively, with no statistical difference between groups. The AST averages were 56.8, 33.0, and 50.1 U/l in groups 1, 2, and 3, respectively, with group 2 significantly differing from the others. Clinical biochemistry values of muscular function in horses varied according to activity category.

  13. Highly n-Type Titanium Oxide as an Electronically Active Support for Platinum in the Catalytic Oxidation of Carbon Monoxide

    KAUST Repository

    Baker, L. Robert; Hervier, Antoine; Seo, Hyungtak; Kennedy, Griffin; Komvopoulos, Kyriakos; Somorjai, Gabor A.

    2011-01-01

    -support interaction is electronic activation of surface adsorbates by charge carriers. Motivated by the goal of using electronic activation to drive nonthermal chemistry, we investigated the ability of the oxide support to mediate charge transfer. We report

  14. Inducible xylitol dehydrogenases in enteric bacteria.

    OpenAIRE

    Doten, R C; Mortlock, R P

    1985-01-01

    Morganella morganii ATCC 25829, Providencia stuartii ATCC 25827, Serratia marcescens ATCC 13880, and Erwinia sp. strain 4D2P were found to induce a xylitol dehydrogenase when grown on a xylitol-containing medium. The xylitol dehydrogenases were partially purified from the four strains, and those from M. morganii ATCC 25829, P. stuartii ATCC 25827, and S. marcescens ATCC 13880 were all found to oxidize xylitol to D-xylulose. These three enzymes had KmS for xylitol of 7.1 to 16.4 mM and molecul...

  15. 2-Methylbutyryl-coenzyme A dehydrogenase deficiency

    DEFF Research Database (Denmark)

    Sass, Jörn Oliver; Ensenauer, Regina; Röschinger, Wulf

    2008-01-01

    2-Methylbutyryl-CoA dehydrogenase (MBD; coded by the ACADSB gene) catalyzes the step in isoleucine metabolism that corresponds to the isovaleryl-CoA dehydrogenase reaction in the degradation of leucine. Deficiencies of both enzymes may be detected by expanded neonatal screening with tandem...... individuals showed clinical symptoms attributable to MBD deficiency although the defect in isoleucine catabolism was demonstrated both in vivo and in vitro. Several mutations in the ACADSB gene were identified, including a novel one. MBD deficiency may be a harmless metabolic variant although significant...

  16. Physiological covalent regulation of rat liver branched-chain alpha-ketoacid dehydrogenase

    International Nuclear Information System (INIS)

    Harris, R.A.; Powell, S.M.; Paxton, R.; Gillim, S.E.; Nagae, H.

    1985-01-01

    A radiochemical assay was developed for measuring branched-chain alpha-ketoacid dehydrogenase activity of Triton X-100 extracts of freeze-clamped rat liver. The proportion of active (dephosphorylated) enzyme was determined by measuring enzyme activities before and after activation of the complex with a broad-specificity phosphoprotein phosphatase. Hepatic branched-chain alpha-ketoacid dehydrogenase activity in normal male Wistar rats was 97% active but decreased to 33% active after 2 days on low-protein (8%) diet and to 13% active after 4 days on the same diet. Restricting protein intake of lean and obese female Zucker rats also caused inactivation of hepatic branched-chain alpha-ketoacid dehydrogenase complex. Essentially all of the enzyme was in the active state in rats maintained for 14 days on either 30 or 50% protein diets. This was also the case for rats maintained on a commercial chow diet (minimum 23% protein). However, maintaining rats on 20, 8, and 0% protein diets decreased the percentage of the active form of the enzyme to 58, 10, and 7% of the total, respectively. Fasting of chow-fed rats for 48 h had no effect on the activity state of hepatic branched-chain alpha-ketoacid dehydrogenase, i.e., 93% of the enzyme remained in the active state compared to 97% for chow-fed rats. However, hepatic enzyme of rats maintained on 8% protein diet was 10% active before starvation and 83% active after 2 days of starvation. Thus, dietary protein deficiency results in inactivation of hepatic branched-chain alpha-ketoacid dehydrogenase complex, presumably as a consequence of low hepatic levels of branched-chain alpha-ketoacids

  17. Electronically Active Impurities in Colloidal Quantum Dot Solids

    KAUST Repository

    Carey, Graham H.

    2014-11-25

    © 2014 American Chemical Society. Colloidal quantum dot films have seen rapid progress as active materials in photodetection, light emission, and photovoltaics. Their processing from the solution phase makes them an attractive option for these applications due to the expected cost reductions associated with liquid-phase material deposition. Colloidally stable nanoparticles capped using long, insulating aliphatic ligands are used to form semiconducting, insoluble films via a solid-state ligand exchange in which the original ligands are replaced with short bifunctional ligands. Here we show that this ligand exchange can have unintended and undesired side effects: a high molecular weight complex can form, containing both lead oleate and the shorter conductive ligand, and this poorly soluble complex can end up embedded within the colloidal quantum dot (CQD) active layer. We further show that, by adding an acidic treatment during film processing, we can break up and wash away these complexes, producing a higher quality CQD solid. The improved material leads to photovoltaic devices with reduced series resistance and enhanced fill factor relative to controls employing previously reported CQD solids. (Figure Presented).

  18. Electronically Active Impurities in Colloidal Quantum Dot Solids

    KAUST Repository

    Carey, Graham H.; Kramer, Illan J.; Kanjanaboos, Pongsakorn; Moreno-Bautista, Gabriel; Voznyy, Oleksandr; Rollny, Lisa; Tang, Joel A.; Hoogland, Sjoerd; Sargent, Edward H.

    2014-01-01

    © 2014 American Chemical Society. Colloidal quantum dot films have seen rapid progress as active materials in photodetection, light emission, and photovoltaics. Their processing from the solution phase makes them an attractive option for these applications due to the expected cost reductions associated with liquid-phase material deposition. Colloidally stable nanoparticles capped using long, insulating aliphatic ligands are used to form semiconducting, insoluble films via a solid-state ligand exchange in which the original ligands are replaced with short bifunctional ligands. Here we show that this ligand exchange can have unintended and undesired side effects: a high molecular weight complex can form, containing both lead oleate and the shorter conductive ligand, and this poorly soluble complex can end up embedded within the colloidal quantum dot (CQD) active layer. We further show that, by adding an acidic treatment during film processing, we can break up and wash away these complexes, producing a higher quality CQD solid. The improved material leads to photovoltaic devices with reduced series resistance and enhanced fill factor relative to controls employing previously reported CQD solids. (Figure Presented).

  19. Electronics

    Science.gov (United States)

    2001-01-01

    International Acer Incorporated, Hsin Chu, Taiwan Aerospace Industrial Development Corporation, Taichung, Taiwan American Institute of Taiwan, Taipei, Taiwan...Singapore and Malaysia .5 - 4 - The largest market for semiconductor products is the high technology consumer electronics industry that consumes up...Singapore, and Malaysia . A new semiconductor facility costs around $3 billion to build and takes about two years to become operational

  20. Modulation of NADP(+)-dependent isocitrate dehydrogenase in aging.

    Science.gov (United States)

    Kil, In Sup; Lee, Young Sup; Bae, Young Seuk; Huh, Tae Lin; Park, Jeen-Woo

    2004-01-01

    NADPH is an important cofactor in many biosynthesis pathways and the regeneration of reduced glutathione, critically important in cellular defense against oxidative damage. It is mainly produced by glucose-6-phosphate dehydrogenase, malic enzyme, and NADP(+)-specific isocitrate dehydrogenases (ICDHs). Here, we investigated age-related changes in ICDH activity and protein expression in IMR-90 human diploid fibroblast cells and tissues from Fischer 344 rats. We found that in IMR-90 cells the activity of cytosolic ICDH (IDPc) gradually increased with age up to the 46-48 population doubling level (PDL) and then gradually decreased at later PDL. 2',7'-Dichloro-fluorescein fluorescence which reflects intracellular ROS generation was increased with aging in IMR-90 cells. In ad libitum-fed rats, we noted age-related, tissue-specific modulations of IDPc and mitochondrial ICDH (IDPm) activities and protein expression in the liver, kidney and testes. In contrast, ICDH activities and protein expression were not significantly modulated in diet-restricted rats. These data suggest that modulation of ICDH is an age-dependent and a tissue-specific phenomenon.

  1. Genetics Home Reference: glucose-6-phosphate dehydrogenase deficiency

    Science.gov (United States)

    ... deficiency Encyclopedia: Glucose-6-phosphate dehydrogenase test Encyclopedia: Hemolytic anemia Encyclopedia: Newborn jaundice Health Topic: Anemia Health Topic: G6PD Deficiency Health Topic: Newborn Screening Genetic and Rare Diseases Information Center (1 link) Glucose-6-phosphate dehydrogenase ...

  2. Control of Glycolysis by Glyceraldehyde-3-Phosphate Dehydrogenase in Streptococcus cremoris and Streptococcus lactis

    NARCIS (Netherlands)

    POOLMAN, B; BOSMAN, B; KONINGS, WN

    1987-01-01

    The decreased response of the energy metabolism of lactose-starved Streptococcus cremoris upon readdition of lactose is caused by a decrease of the glycolytic activity. The decrease in glycolysis is accompanied by a decrease in the activities of glyceraldehyde-3-phosphate dehydrogenase and

  3. Characterization of GDP-mannose dehydrogenase from the brown alga Ectocarpus siliculosus providing the precursor for the alginate polymer.

    Science.gov (United States)

    Tenhaken, Raimund; Voglas, Elena; Cock, J Mark; Neu, Volker; Huber, Christian G

    2011-05-13

    Alginate is a major cell wall polymer of brown algae. The precursor for the polymer is GDP-mannuronic acid, which is believed to be derived from a four-electron oxidation of GDP-mannose through the enzyme GDP-mannose dehydrogenase (GMD). So far no eukaryotic GMD has been biochemically characterized. We have identified a candidate gene in the Ectocarpus siliculosus genome and expressed it as a recombinant protein in Escherichia coli. The GMD from Ectocarpus differs strongly from related enzymes in bacteria and is as distant to the bacterial proteins as it is to the group of UDP-glucose dehydrogenases. It lacks the C-terminal ∼120 amino acid domain present in bacterial GMDs, which is believed to be involved in catalysis. The GMD from brown algae is highly active at alkaline pH and contains a catalytic Cys residue, sensitive to heavy metals. The product GDP-mannuronic acid was analyzed by HPLC and mass spectroscopy. The K(m) for GDP-mannose was 95 μM, and 86 μM for NAD(+). No substrate other than GDP-mannose was oxidized by the enzyme. In gel filtration experiments the enzyme behaved as a dimer. The Ectocarpus GMD is stimulated by salts even at low molar concentrations as a possible adaptation to marine life. It is rapidly inactivated at temperatures above 30 °C.

  4. Electron beam injection during active experiments. 2. Collisional effects

    International Nuclear Information System (INIS)

    Winglee, R.M.

    1990-01-01

    During active beam experiments the presence of high neutral densities at low altitudes and/or during thruster firings has been observed to modify the spacecraft charging and the properties of the beam. Two-dimensional (three velocity) electromagnetic particle simulations with ionizing collisions incorporated are used to investigate the modification of the beam-plasma interaction as the neutral density is increased. It is shown that when the spacecraft is uniformly immersed in a neutral cloud, most of the ionization is produced by direct ionization by the beam and its secondaries, rather than via vehicle-induced or wave-ineuced ionization for the neutral densities considered. This ionization enhances the return current into the spacecraft with the spacecraft potential being reduced well below the beam energy whent he collison period is shorter than the spacecraft charging time. Neutral densities of about 10 11 -10 12 cm -3 are required to produce this reduction in the spacecraft potential for typical ionospheric and beam parameters. At these densities, the beam is able to propagate away from the spacecraft with little distortion except in the case of thruster firings where the beam can be subject to large space-charge oscillations near the boundaries of the neutral cloud. The ionization of neutrals in the beam region also modifies the wave emissions and spatial profile of return currents into the spacecraft, both of which tend to become localized to the beam region in high neutral densities

  5. Electron microscopy studies of activation mechanisms in hydrotreating catalysis

    DEFF Research Database (Denmark)

    Dahl-Petersen, Christian

    The aim of this work is to remedy the limited fundamental insight that exists in terms of the activation and formation of hydrotreating catalysts utilized in industrial oil refining of crude oil. This is done through numerous studies of the conversion of industrially relevant molybdenum oxide...... larger amount of formed MoS2. MoS2 forms in one of two conformations of the two-dimensional atomic structure that is either in an orientation parallel or perpendicular to the nanoparticle surface. Both the initial growth of MoS2 and the subsequent formation of multi-layered structures is addressed....... This shows that initial growth tends to form an apparent bond between the MoO2 surface and the MoS2 edge and that the layer size increases through coalescence. For multi-layered structures, it is found that MoS2 layers grow through a layer-under-layer mechanism, where defects in the outer layers enable...

  6. Optimization of Adsorptive Immobilization of Alcohol Dehydrogenases

    NARCIS (Netherlands)

    Trivedi, Archana; Heinemann, Matthias; Spiess, Antje C.; Daussmann, Thomas; Büchs, Jochen

    2005-01-01

    In this work, a systematic examination of various parameters of adsorptive immobilization of alcohol dehydrogenases (ADHs) on solid support is performed and the impact of these parameters on immobilization efficiency is studied. Depending on the source of the enzymes, these parameters differently

  7. Inactivation of pyruvate dehydrogenase kinase 2 by mitochondrial reactive oxygen species.

    Science.gov (United States)

    Hurd, Thomas R; Collins, Yvonne; Abakumova, Irina; Chouchani, Edward T; Baranowski, Bartlomiej; Fearnley, Ian M; Prime, Tracy A; Murphy, Michael P; James, Andrew M

    2012-10-12

    Reactive oxygen species are byproducts of mitochondrial respiration and thus potential regulators of mitochondrial function. Pyruvate dehydrogenase kinase 2 (PDHK2) inhibits the pyruvate dehydrogenase complex, thereby regulating entry of carbohydrates into the tricarboxylic acid (TCA) cycle. Here we show that PDHK2 activity is inhibited by low levels of hydrogen peroxide (H(2)O(2)) generated by the respiratory chain. This occurs via reversible oxidation of cysteine residues 45 and 392 on PDHK2 and results in increased pyruvate dehydrogenase complex activity. H(2)O(2) derives from superoxide (O(2)(.)), and we show that conditions that inhibit PDHK2 also inactivate the TCA cycle enzyme, aconitase. These findings suggest that under conditions of high mitochondrial O(2)(.) production, such as may occur under nutrient excess and low ATP demand, the increase in O(2)() and H(2)O(2) may provide feedback signals to modulate mitochondrial metabolism.

  8. Electron transfer flavoprotein deficiency: Functional and molecular aspects

    DEFF Research Database (Denmark)

    Schiff, M; Froissart, R; Olsen, Rikke Katrine Jentoft

    2006-01-01

    Multiple acyl-CoA dehydrogenase deficiency (MADD) is a recessively inherited metabolic disorder that can be due to a deficiency of electron transfer flavoprotein (ETF) or its dehydrogenase (ETF-ubiquinone oxidoreductase). ETF is a mitochondrial matrix protein consisting of alpha- (30kDa) and beta......- (28kDa) subunits encoded by the ETFA and ETFB genes, respectively. In the present study, we have analysed tissue samples from 16 unrelated patients with ETF deficiency, and we report the results of ETF activity, Western blot analysis and mutation analysis. The ETF assay provides a reliable diagnostic...... tool to confirm ETF deficiency in patients suspected to suffer from MADD. Activity ranged from less than 1 to 16% of controls with the most severely affected patients disclosing the lowest activity values. The majority of patients had mutations in the ETFA gene while only two of them harboured...

  9. Electronic dosimetry and neutron metrology by CMOS active pixel sensor

    International Nuclear Information System (INIS)

    Vanstalle, M.

    2011-01-01

    This work aims at demonstrating the possibility to use active pixel sensors as operational neutron dosemeters. To do so, the sensor that has been used has to be γ-transparent and to be able to detect neutrons on a wide energy range with a high detection efficiency. The response of the device, made of the CMOS sensor MIMOSA-5 and a converter in front of the sensor (polyethylene for fast neutron detection and 10 B for thermal neutron detection), has been compared with Monte Carlo simulations carried out with MCNPX and GEANT4. These codes have been before-hand validated to check they can be used properly for our application. Experiments to characterize the sensor have been performed at IPHC and at IRSN/LMDN (Cadarache). The results of the sensor irradiation to photon sources and mixed field ( 241 AmBe source) show the γ-transparency of the sensor by applying an appropriate threshold on the deposited energy (around 100 keV). The associated detection efficiency is satisfactory with a value of 10 -3 , in good agreement with MCNPX and GEANT4. Other features of the device have been tested with the same source, like the angular response. The last part of this work deals with the detection of thermal neutrons (eV-neutrons). Assays have been done in Cadarache (IRSN) with a 252 Cf source moderated with heavy water (with and without cadmium shell). Results asserted a very high detection efficiency (up to 6*10 -3 for a pure 10 B converter) in good agreement with GEANT4. (author)

  10. Acquired multiple Acyl-CoA dehydrogenase deficiency in 10 horses with atypical myopathy.

    Science.gov (United States)

    Westermann, C M; Dorland, L; Votion, D M; de Sain-van der Velden, M G M; Wijnberg, I D; Wanders, R J A; Spliet, W G M; Testerink, N; Berger, R; Ruiter, J P N; van der Kolk, J H

    2008-05-01

    The aim of the current study was to assess lipid metabolism in horses with atypical myopathy. Urine samples from 10 cases were subjected to analysis of organic acids, glycine conjugates, and acylcarnitines revealing increased mean excretion of lactic acid, ethylmalonic acid, 2-methylsuccinic acid, butyrylglycine, (iso)valerylglycine, hexanoylglycine, free carnitine, C2-, C3-, C4-, C5-, C6-, C8-, C8:1-, C10:1-, and C10:2-carnitine as compared with 15 control horses (12 healthy and three with acute myopathy due to other causes). Analysis of plasma revealed similar results for these predominantly short-chain acylcarnitines. Furthermore, measurement of dehydrogenase activities in lateral vastus muscle from one horse with atypical myopathy indeed showed deficiencies of short-chain acyl-CoA dehydrogenase (0.66 as compared with 2.27 and 2.48 in two controls), medium-chain acyl-CoA dehydrogenase (0.36 as compared with 4.31 and 4.82 in two controls) and isovaleryl-CoA dehydrogenase (0.74 as compared with 1.43 and 1.61 nmol min(-1) mg(-1) in two controls). A deficiency of several mitochondrial dehydrogenases that utilize flavin adenine dinucleotide as cofactor including the acyl-CoA dehydrogenases of fatty acid beta-oxidation, and enzymes that degrade the CoA-esters of glutaric acid, isovaleric acid, 2-methylbutyric acid, isobutyric acid, and sarcosine was suspected in 10 out of 10 cases as the possible etiology for a highly fatal and prevalent toxic equine muscle disease similar to the combined metabolic derangements seen in human multiple acyl-CoA dehydrogenase deficiency also known as glutaric acidemia type II.

  11. Suitability of the hydrocarbon-hydroxylating molybdenum-enzyme ethylbenzene dehydrogenase for industrial chiral alcohol production.

    Science.gov (United States)

    Tataruch, M; Heider, J; Bryjak, J; Nowak, P; Knack, D; Czerniak, A; Liesiene, J; Szaleniec, M

    2014-12-20

    The molybdenum/iron-sulfur/heme protein ethylbenzene dehydrogenase (EbDH) was successfully applied to catalyze enantiospecific hydroxylation of alkylaromatic and alkylheterocyclic compounds. The optimization of the synthetic procedure involves use of the enzyme in a crude purification state that saves significant preparation effort and is more stable than purified EbDH without exhibiting unwanted side reactions. Moreover, immobilization of the enzyme on a crystalline cellulose support and changes in reaction conditions were introduced in order to increase the amounts of product formed (anaerobic atmosphere, electrochemical electron acceptor recycling or utilization of ferricyanide as alternative electron acceptor in high concentrations). We report here on an extension of effective enzyme activity from 4h to more than 10 days and final product yields of up to 0.4-0.5g/l, which represent a decent starting point for further optimization. Therefore, we expect that the hydrocarbon-hydroxylation capabilities of EbDH may be developed into a new process of industrial production of chiral alcohols. Copyright © 2014 Elsevier B.V. All rights reserved.

  12. Activity of flavonoids through λ sub max and electron cross-section

    International Nuclear Information System (INIS)

    Murthy, V.R.; Sreenivasulu, M.

    1997-01-01

    Flavonoids are widespread groups of natural constituents and present in the drugs in the form of mono or diglycosides. Being physiologically active, flavonoids are important in the field of pharmacological and clinical applications. Not many physical properties of flavonoids have been studied so far excepting UV and NMR studies. This paper deals with the evaluation of electron ionization cross section through λ sub max, a parameter available from UV studies. Electron ionization cross section was primarily conceived to be of use in radiation chemical data, mass spectroscopic and thermodynamic studies. But later attempts to correlate electron ionization cross-section with structural and related parameters prompted the authors to derive an explicit expression relating λ sub max and electron ionization cross-section (Q). The application of this method to correlate Q through λ sub max and interpret the results in terms of chemical activity are discussed

  13. Discovery of Clinical Candidate 2-((2S,6 S)-2-Phenyl-6-hydroxyadamantan-2-yl)-1-(3'-hydroxyazetidin-1-yl)ethanone [BMS-816336], an Orally Active Novel Selective 11β-Hydroxysteroid Dehydrogenase Type 1 Inhibitor

    Energy Technology Data Exchange (ETDEWEB)

    Ye, Xiang-Yang; Chen, Stephanie Y.; Wu, Shung; Yoon, David S.; Wang, Haixia; Hong, Zhenqiu; O’Connor, Stephen P.; Li, Jun; Li, James J.; Kennedy, Lawrence J.; Walker, Steven J.; Nayeem, Akbar; Sheriff, Steven; Camac, Daniel M.; Ramamurthy, Vidyhashankar; Morin, Paul E.; Zebo, Rachel; Taylor, Joseph R.; Morgan, Nathan N.; Ponticiello, Randolph P.; Harrity, Thomas; Apedo, Atsu; Golla, Rajasree; Seethala, Ramakrishna; Wang, Mengmeng; Harper, Timothy W.; Sleczka, Bogdan G.; He, Bin; Kirby, Mark; Leahy, David K.; Li, Jianqing; Hanson, Ronald L.; Guo, Zhiwei; Li, Yi-Xin; DiMarco, John D.; Scaringe, Raymond; Maxwell, Brad; Moulin, Frederick; Barrish, Joel C.; Gordon, David A.; Robl, Jeffrey A.

    2017-06-05

    BMS-816336 (6n-2), a hydroxy-substituted adamantyl acetamide, has been identified as a novel, potent inhibitor against human 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) enzyme (IC50 3.0 nM) with >10000-fold selectivity over human 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2). 6n-2 exhibits a robust acute pharmacodynamic effect in cynomolgus monkeys (ED50 0.12 mg/kg) and in DIO mice. It is orally bioavailable (%F ranges from 20 to 72% in preclinical species) and has a predicted pharmacokinetic profile of a high peak to trough ratio and short half-life in humans. This ADME profile met our selection criteria for once daily administration, targeting robust inhibition of 11β-HSD1 enzyme for the first 12 h period after dosing followed by an “inhibition holiday” so that the potential for hypothalamic–pituitary–adrenal (HPA) axis activation might be mitigated. 6n-2 was found to be well-tolerated in phase 1 clinical studies and represents a potential new treatment for type 2 diabetes, metabolic syndrome, and other human diseases modulated by glucocorticoid control.

  14. Electron transfer activation of a second water channel for proton transport in [FeFe]-hydrogenase

    Energy Technology Data Exchange (ETDEWEB)

    Sode, Olaseni; Voth, Gregory A., E-mail: gavoth@uchicago.edu [Department of Chemistry, James Franck Institute, Institute for Biophysical Dynamics, Computation Institute, The University of Chicago, Chicago, Illinois 60637, USA and Computing, Environment and Life Sciences, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

    2014-12-14

    Hydrogenase enzymes are important because they can reversibly catalyze the production of molecular hydrogen. Proton transport mechanisms have been previously studied in residue pathways that lead to the active site of the enzyme via residues Cys299 and Ser319. The importance of this pathway and these residues has been previously exhibited through site-specific mutations, which were shown to interrupt the enzyme activity. It has been shown recently that a separate water channel (WC2) is coupled with electron transport to the active site of the [FeFe]-hydrogenase. The water-mediated proton transport mechanisms of the enzyme in different electronic states have been studied using the multistate empirical valence bond reactive molecular dynamics method, in order to understand any role WC2 may have in facilitating the residue pathway in bringing an additional proton to the enzyme active site. In a single electronic state A{sup 2−}, a water wire was formed through which protons can be transported with a low free energy barrier. The remaining electronic states were shown, however, to be highly unfavorable to proton transport in WC2. A double amino acid substitution is predicted to obstruct proton transport in electronic state A{sup 2-} by closing a cavity that could otherwise fill with water near the proximal Fe of the active site.

  15. Electron transfer activation of a second water channel for proton transport in [FeFe]-hydrogenase

    International Nuclear Information System (INIS)

    Sode, Olaseni; Voth, Gregory A.

    2014-01-01

    Hydrogenase enzymes are important because they can reversibly catalyze the production of molecular hydrogen. Proton transport mechanisms have been previously studied in residue pathways that lead to the active site of the enzyme via residues Cys299 and Ser319. The importance of this pathway and these residues has been previously exhibited through site-specific mutations, which were shown to interrupt the enzyme activity. It has been shown recently that a separate water channel (WC2) is coupled with electron transport to the active site of the [FeFe]-hydrogenase. The water-mediated proton transport mechanisms of the enzyme in different electronic states have been studied using the multistate empirical valence bond reactive molecular dynamics method, in order to understand any role WC2 may have in facilitating the residue pathway in bringing an additional proton to the enzyme active site. In a single electronic state A 2− , a water wire was formed through which protons can be transported with a low free energy barrier. The remaining electronic states were shown, however, to be highly unfavorable to proton transport in WC2. A double amino acid substitution is predicted to obstruct proton transport in electronic state A 2- by closing a cavity that could otherwise fill with water near the proximal Fe of the active site

  16. Glucose-6-phosphate dehydrogenase in rat lung alveolar epithelial cells. An ultrastructural enzyme-cytochemical study

    Directory of Open Access Journals (Sweden)

    S Matsubara

    2010-01-01

    Full Text Available Glucose-6-phosphate dehydrogenase (G6PD is the key enzyme of the pentose phosphate pathway in carbohydrate metabolism, and it plays an important role in cell proliferation and antioxidant regulation within cells in various organs. Although marked cell proliferation and oxidant/antioxidant metabolism occur in lung alveolar epithelial cells, definite data has been lacking as to whether cytochemically detectable G6PD is present in alveolar epithelial cells. The distribution pattern of G6PD within these cells, if it is present, is also unknown. The purpose of the present study was to investigate the subcellular localization of G6PD in alveolar cells in the rat lung using a newly- developed enzyme-cytochemistry (copper-ferrocyanide method. Type I cells and stromal endothelia and fibroblasts showed no activities. Electron-dense precipitates indicating G6PD activity were clearly visible in the cytoplasm and on the cytosolic side of the endoplasmic reticulum of type II alveolar epithelial cells. The cytochemical controls ensured specific detection of enzyme activity. This enzyme may play a role in airway defense by delivering substances for cell proliferation and antioxidant forces, thus maintaining the airway architecture.

  17. Relationship between Antifungal Activity against Candida albicans and Electron Parameters of Selected N-Heterocyclic Thioamides

    Science.gov (United States)

    Stachowicz, Jadwiga; Krajewska-Kułak, Elżbieta; Łukaszuk, Cecylia; Niewiadomy, A.

    2014-01-01

    Due to the increasing demand for new pharmaceuticals showing biological activity against pathogenic microorganisms, there is increasing search for new compounds with predicted biological activity. Variously substituted thioamide derivatives with 1.3 and 1.2 ring of thiazole and 1,3,4-thiadiazole, as well as pyrazole were assessed for their activity against Candida albicans. Activity of majority of tested thioamides was larger as compared with that of the reference drugs. The electron parameters of obtained N-heterocyclic thioamides were determined and dependencies on their biological activity against Candida albicans were studied. The best electron compliance of produced bindings with the activity against Candida albicans was observed for the derivatives containing 1,3,4-thiadiazole ring. PMID:25284926

  18. Cathodoluminescence-activated nanoimaging: noninvasive near-field optical microscopy in an electron microscope.

    Science.gov (United States)

    Bischak, Connor G; Hetherington, Craig L; Wang, Zhe; Precht, Jake T; Kaz, David M; Schlom, Darrell G; Ginsberg, Naomi S

    2015-05-13

    We demonstrate a new nanoimaging platform in which optical excitations generated by a low-energy electron beam in an ultrathin scintillator are used as a noninvasive, near-field optical scanning probe of an underlying sample. We obtain optical images of Al nanostructures with 46 nm resolution and validate the noninvasiveness of this approach by imaging a conjugated polymer film otherwise incompatible with electron microscopy due to electron-induced damage. The high resolution, speed, and noninvasiveness of this "cathodoluminescence-activated" platform also show promise for super-resolution bioimaging.

  19. Physiological regulation of isocitrate dehydrogenase and the role of 2-oxoglutarate in Prochlorococcus sp. strain PCC 9511.

    Directory of Open Access Journals (Sweden)

    María Agustina Domínguez-Martín

    Full Text Available The enzyme isocitrate dehydrogenase (ICDH; EC 1.1.1.42 catalyzes the oxidative decarboxylation of isocitrate, to produce 2-oxoglutarate. The incompleteness of the tricarboxylic acids cycle in marine cyanobacteria confers a special importance to isocitrate dehydrogenase in the C/N balance, since 2-oxoglutarate can only be metabolized through the glutamine synthetase/glutamate synthase pathway. The physiological regulation of isocitrate dehydrogenase was studied in cultures of Prochlorococcus sp. strain PCC 9511, by measuring enzyme activity and concentration using the NADPH production assay and Western blotting, respectively. The enzyme activity showed little changes under nitrogen or phosphorus starvation, or upon addition of the inhibitors DCMU, DBMIB and MSX. Azaserine, an inhibitor of glutamate synthase, induced clear increases in the isocitrate dehydrogenase activity and icd gene expression after 24 h, and also in the 2-oxoglutarate concentration. Iron starvation had the most significant effect, inducing a complete loss of isocitrate dehydrogenase activity, possibly mediated by a process of oxidative inactivation, while its concentration was unaffected. Our results suggest that isocitrate dehydrogenase responds to changes in the intracellular concentration of 2-oxoglutarate and to the redox status of the cells in Prochlorococcus.

  20. Biochemical Characterization of Putative Adenylate Dimethylallyltransferase and Cytokinin Dehydrogenase from Nostoc sp. PCC 7120.

    Science.gov (United States)

    Frébortová, Jitka; Greplová, Marta; Seidl, Michael F; Heyl, Alexander; Frébort, Ivo

    2015-01-01

    Cytokinins, a class of phytohormones, are adenine derivatives common to many different organisms. In plants, these play a crucial role as regulators of plant development and the reaction to abiotic and biotic stress. Key enzymes in the cytokinin synthesis and degradation in modern land plants are the isopentyl transferases and the cytokinin dehydrogenases, respectively. Their encoding genes have been probably introduced into the plant lineage during the primary endosymbiosis. To shed light on the evolution of these proteins, the genes homologous to plant adenylate isopentenyl transferase and cytokinin dehydrogenase were amplified from the genomic DNA of cyanobacterium Nostoc sp. PCC 7120 and expressed in Escherichia coli. The putative isopentenyl transferase was shown to be functional in a biochemical assay. In contrast, no enzymatic activity was detected for the putative cytokinin dehydrogenase, even though the principal domains necessary for its function are present. Several mutant variants, in which conserved amino acids in land plant cytokinin dehydrogenases had been restored, were inactive. A combination of experimental data with phylogenetic analysis indicates that adenylate-type isopentenyl transferases might have evolved several times independently. While the Nostoc genome contains a gene coding for protein with characteristics of cytokinin dehydrogenase, the organism is not able to break down cytokinins in the way shown for land plants.

  1. A high effective NADH-ferricyanide dehydrogenase coupled with laccase for NAD(+) regeneration.

    Science.gov (United States)

    Wang, Jizhong; Yang, Chengli; Chen, Xing; Bao, Bingxin; Zhang, Xuan; Li, Dali; Du, Xingfan; Shi, Ruofu; Yang, Junfang; Zhu, Ronghui

    2016-08-01

    To find an efficient and cheap system for NAD(+) regeneration A NADH-ferricyanide dehydrogenase was obtained from an isolate of Escherichia coli. Optimal activity of the NADH dehydrogenase was at 45 °C and pH 7.5, with a K m value for NADH of 10 μM. By combining the NADH dehydrogenase, potassium ferricyanide and laccase, a bi-enzyme system for NAD(+) regeneration was established. The system is attractive in that the O2 consumed by laccase is from air and the sole byproduct of the reaction is water. During the reaction process, 10 mM NAD(+) was transformed from NADH in less than 2 h under the condition of 0.5 U NADH dehydrogenase, 0.5 U laccase, 0.1 mM potassium ferricyanide at pH 5.6, 30 °C CONCLUSION: The bi-enzyme system employed the NADH-ferricyanide dehydrogenase and laccase as catalysts, and potassium ferricyanide as redox mediator, is a promising alternative for NAD(+) regeneration.

  2. Electron-topological investigation of the structure-antitumor activity relationship of thiosemicarbazone derivatives.

    Science.gov (United States)

    Dimoglo, A S; Chumakov, Y M; Dobrova, B N; Saracoglu, M

    1997-04-01

    In the frameworks of the electron-topological method (ETM) the structure-antitumor activity relationship was investigated for a series of thiosemicarbazone derivatives. The series included 70 compounds. Conformational analysis and quantum-chemical calculations were carried out for each compound. The revealed activity feature showed a satisfactory description of the class of active compounds according to two different parameters P and alpha estimating the probabilities of the feature realization in the class of active compounds (they are equal to 0.94 and 0.86, correspondingly). The results of testing demonstrated the high ability of ETM in predicting the activity investigated.

  3. The radiation inactivation of glutamate and isocitrate dehydrogenases

    International Nuclear Information System (INIS)

    El Failat, R.R.A.

    1980-12-01

    The reaction of free radicals produced by ionizing radiation with the enzymes glutamate dehydrogenase (GDH) and NADP + -specific isocitrate dehydrogenase (ICDH) have been studied by steady-state and pulse radiolysis techniques. In de-aerated GDH solutions, hydroxyl radicals have been found to be the most efficient of the primary radicals generated from water in causing inactivation. The effect of reaction with the enzyme of selective free radicals (SCN) 2 - , (Br) 2 - and (I) 2 - on its activity has also been studied. In neutral solutions, the order of inactivating effectiveness is (I) 2 - > (Br) 2 - > (SCN) 2 - . In the case of the thiocyanate radical anion (SCN) 2 - , the inactivation efficiency is found to depend on KSCN concentration. The radiation inactivation of GDH at both neutral and alkaline pH is accompanied by the loss of sulphydryl groups. Pulse radiolysis was also used to determine the rate constants and the transient absorption spectra following the reaction of the free radicals with GDH. 60 Co-γ-radiolysis and pulse radiolysis were also used to study the effect of ionizing radiation on the activity of ICDH. The results obtained were similar to those of GDH. (author)

  4. Correlation between biological activity and electron transferring of bovine liver catalase: Osmolytes effects

    International Nuclear Information System (INIS)

    Tehrani, H. Sepasi; Moosavi-Movahedi, A.A.; Ghourchian, H.

    2013-01-01

    Highlights: • Proline increases ET in Bovine Liver Catalase (BLC) whereas histidine decreases it. • Proline also increased the biological activity, whereas histidine decreased it. • Electron transferring and biological activity for BLC are directly correlated. • Proline causes favorable ET for BLC shown by positive E 1/2 (E°′) and negative ΔG. • Histidine makes ET unfavorable for BLC, manifested by E 1/2 (E°′) 0. -- Abstract: Catalase is a crucial antioxidant enzyme that protects life against detrimental effects of H 2 O 2 by disproportionating it into water and molecular oxygen. Effect of proline as a compatible and histidine as a non compatible osmolyte on the electron transferring and midpoint potential of catalase has been investigated. Proline increases the midpoint potential (ΔE m > 0), therefore causing the ΔG ET to be less positive and making the electron transfer reaction more facile whereas histidine decreases the E m (ΔE m ET , thereby rendering the electron transfer reaction less efficient. These results indicate the inhibitory effect of histidine evident by a −37% decrease in the cathodic peak current compared to 16% increase in the case of proline indicative of activation. The insight paves the tedious way towards our ultimate goal of elucidating a correlation between biological activity and electron transferring

  5. Effect of electron-beam irradiation on the antioxidant activity of extracts from Citrus unshiu pomaces

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong-Wan [Department of Food Science and Biotechnology, Kyungnam University, Masan 631-701 (Korea, Republic of); Lee, Byung Cheol [Laboratory for Quantum Optics, Korea Atomic Energy Research Institute, Daejeon 305-600 (Korea, Republic of); Lee, Jong-Hwa [School of Bioresource Sciences, Andong National University, Andong 760-749 (Korea, Republic of); Nam, Ki-Chang [Chemistry and Biotechnology Examinations Bureau, Korean Intellectual Property Office, Daejeon 302-701 (Korea, Republic of); Lee, Seung-Cheol [Department of Food Science and Biotechnology, Kyungnam University, Masan 631-701 (Korea, Republic of)], E-mail: sclee@kyungnam.ac.kr

    2008-01-15

    After electron-beam irradiation of citrus pomaces (CP), the total phenolic content (TPC), radical scavenging activity (RSA), and reducing power (RP) were evaluated. When CP were irradiated at 37.9 kGy; the TPC, RSA and RP of water extract of CP increased from 6543.2 to 7405.4 {mu}M, 37.6% to 52.9%, and 0.64 to 0.90, respectively, compared with the non-irradiated control. The results indicate that the electron-beam irradiation can be an efficient process for increasing the antioxidant activity of CP.

  6. Construction of an integrated enzyme system consisting azoreductase and glucose 1-dehydrogenase for dye removal.

    Science.gov (United States)

    Yang, Yuyi; Wei, Buqing; Zhao, Yuhua; Wang, Jun

    2013-02-01

    Azo dyes are toxic and carcinogenic and are often present in industrial effluents. In this research, azoreductase and glucose 1-dehydrogenase were coupled for both continuous generation of the cofactor NADH and azo dye removal. The results show that 85% maximum relative activity of azoreductase in an integrated enzyme system was obtained at the conditions: 1U azoreductase:10U glucose 1-dehydrogenase, 250mM glucose, 1.0mM NAD(+) and 150μM methyl red. Sensitivity analysis of the factors in the enzyme system affecting dye removal examined by an artificial neural network model shows that the relative importance of enzyme ratio between azoreductase and glucose 1-dehydrogenase was 22%, followed by dye concentration (27%), NAD(+) concentration (23%) and glucose concentration (22%), indicating none of the variables could be ignored in the enzyme system. Batch results show that the enzyme system has application potential for dye removal. Copyright © 2012 Elsevier Ltd. All rights reserved.

  7. Localization of xanthine oxidoreductase activity using the tissue protectant polyvinyl alcohol and final electron acceptor Tetranitro BT

    NARCIS (Netherlands)

    Kooij, A.; Frederiks, W. M.; Gossrau, R.; van Noorden, C. J.

    1991-01-01

    We have detected xanthine oxidoreductase activity in unfixed cryostat sections of rat and chicken liver, rat duodenum, and bovine mammary gland using the tissue protectant polyvinyl alcohol, the electron carrier 1-methoxyphenazine methosulfate, the final electron acceptor Tetranitro BT, and

  8. Adherence to active play and electronic media guidelines in preschool children: gender and parental education considerations.

    Science.gov (United States)

    Loprinzi, Paul D; Schary, David P; Cardinal, Bradley J

    2013-01-01

    The primary purpose of the present study was to examine adherence to current active play and electronic media use guidelines in a sample of US preschool-aged children and to examine whether differences occurred across gender and parental education. 164 parents completed an on-line survey to estimate preschool children's active play and sedentary behaviors. For weekdays, 50% of the sample met the active play guideline with this increasing to 65% during the weekend. With respect to electronic media use, 90% of the sample met guidelines during the week, with the percentage meeting guidelines dropping to 78% during the weekend. A greater percentage of preschool children from high parental education families (83.4 ± 3.3) met electronic media use guidelines on the weekends, compared to preschool children from low parental education families (59.4 ± 8.1) (p = 0.002). Our findings indicate that a substantial portion of preschool children are not meeting active play guidelines and that adherence to active play and electronic media use guidelines may be influenced by parental education.

  9. Homology modelling and docking analysis of L-lactate dehydrogenase from Streptococcus thermopilus

    Directory of Open Access Journals (Sweden)

    Vukić Vladimir R.

    2016-01-01

    Full Text Available The aim of this research was to create a three-dimensional model of L-lactate dehydrogenase from the main yoghurt starter culture - Streptococcus thermopilus, to analyse its structural features and investigate substrate binding in the active site. NCBI BlastP was used against the Protein Data Bank database in order to identify the template for construction of homology models. Multiple sequence alignment was performed using the program MUSCULE within the UGENE 1.11.3 program. Homology models were constructed using the program Modeller v. 9.17. The obtained 3D model was verified by Ramachandran plots. Molecular docking simulations were performed using the program Surflex-Dock. The highest sequence similarity was observed with L-lactate dehydrogenase from Lactobacillus casei subsp. casei, with 69% identity. Therefore, its structure (PDB ID: 2ZQY:A was selected as a modelling template for homology modelling. Active residues are by sequence similarity predicted: S. thermophilus - HIS181 and S. aureus - HIS179. Binding energy of pyruvate to L-lactate dehydrogenase of S. thermopilus was - 7.874 kcal/mol. Pyruvate in L-lactate dehydrogenase of S. thermopilus makes H bonds with catalytic HIS181 (1.9 Å, as well as with THR235 (3.6 Å. Although our results indicate similar position of substrates between L-lactate dehydrogenase of S. thermopilus and S. aureus, differences in substrate distances and binding energy values could influence the reaction rate. Based on these results, the L-lactate dehydrogenase model proposed here could be used as a guide for further research, such as transition states of the reaction through molecular dynamics. [Projekat Ministarstva nauke Republike Srbije, br. III 46009

  10. Charge transfer dynamics from adsorbates to surfaces with single active electron and configuration interaction based approaches

    Energy Technology Data Exchange (ETDEWEB)

    Ramakrishnan, Raghunathan, E-mail: r.ramakrishnan@unibas.ch [Institute of Physical Chemistry, National Center for Computational Design and Discovery of Novel Materials (MARVEL), Department of Chemistry, University of Basel, Klingelbergstrasse 80, CH-4056 Basel (Switzerland); Nest, Mathias [Theoretische Chemie, Technische Universität München, Lichtenbergstr. 4, 85747 Garching (Germany)

    2015-01-13

    Highlights: • We model electron dynamics across cyano alkanethiolates attached to gold cluster. • We present electron transfer time scales from TD-DFT and TD-CI based simulations. • Both DFT and CI methods qualitatively predict the trend in time scales. • TD-CI predicts the experimental relative time scale very accurately. - Abstract: We employ wavepacket simulations based on many-body time-dependent configuration interaction (TD-CI), and single active electron theories, to predict the ultrafast molecule/metal electron transfer time scales, in cyano alkanethiolates bonded to model gold clusters. The initial states represent two excited states where a valence electron is promoted to one of the two virtual π{sup ∗} molecular orbitals localized on the cyanide fragment. The ratio of the two time scales indicate the efficiency of one charge transfer channel over the other. In both our one-and many-electron simulations, this ratio agree qualitatively with each other as well as with the previously reported experimental time scales (Blobner et al., 2012), measured for a macroscopic metal surface. We study the effect of cluster size and the description of electron correlation on the charge transfer process.

  11. Direct observation of children's preferences and activity levels during interactive and online electronic games.

    Science.gov (United States)

    Sit, Cindy H P; Lam, Jessica W K; McKenzie, Thomas L

    2010-07-01

    Interactive electronic games have recently been popularized and are believed to help promote children's physical activity (PA). The purpose of the study was to examine preferences and PA levels during interactive and online electronic games among overweight and nonoverweight boys and girls. Using a modification of the SOFIT, we systematically observed 70 Hong Kong Chinese children (35 boys, 35 girls; 50 nonoverweight, 20 overweight), age 9 to 12 years, during 2 60-minute recreation sessions and recorded their game mode choices and PA levels. During Session One children could play either an interactive or an online electronic bowling game and during Session Two they could play an interactive or an online electronic running game. Children chose to play the games during 94% of session time and split this time between interactive (52%) and online (48%) versions. They engaged in significantly more moderate-to-vigorous physical activity (MVPA) during interactive games than their online electronic versions (70% vs. 2% of game time). Boys and nonoverweight children expended relatively more energy during the interactive games than girls and overweight children, respectively. New-generation interactive games can facilitate physical activity in children, and given the opportunity children may select them over sedentary versions.

  12. The Alcohol Dehydrogenase Kinetics Laboratory: Enhanced Data Analysis and Student-Designed Mini-Projects

    Science.gov (United States)

    Silverstein, Todd P.

    2016-01-01

    A highly instructive, wide-ranging laboratory project in which students study the effects of various parameters on the enzymatic activity of alcohol dehydrogenase has been adapted for the upper-division biochemistry and physical biochemistry laboratory. Our two main goals were to provide enhanced data analysis, featuring nonlinear regression, and…

  13. Characterisation of recombinant human fatty aldehyde dehydrogenase: implications for Sjögren-Larsson syndrome

    NARCIS (Netherlands)

    Lloyd, Matthew D.; Boardman, Kieren D. E.; Smith, Andrew; van den Brink, Daan M.; Wanders, Ronald J. A.; Threadgill, Michael D.

    2007-01-01

    Fatty aldehyde dehydrogenase (FALDH) is an NAD+-dependent oxidoreductase involved in the metabolism of fatty alcohols. Enzyme activity has been implicated in the pathology of diabetes and cancer. Mutations in the human gene inactivate the enzyme and cause accumulation of fatty alcohols in

  14. A survey of cyclic replacements for the central diamide moiety of inhibitors of inosine monophosphate dehydrogenase.

    Science.gov (United States)

    Dhar, T G Murali; Liu, Chunjian; Pitts, William J; Guo, Junquing; Watterson, Scott H; Gu, Henry; Fleener, Catherine A; Rouleau, Katherine; Sherbina, N Z; Barrish, Joel C; Hollenbaugh, Diane; Iwanowicz, Edwin J

    2002-11-04

    A series of heterocyclic replacements for the central diamide moiety of 1, a potent small molecule inhibitor of inosine monophosphate dehydrogenase (IMPDH) were explored The synthesis and the structure-activity relationships (SARs), derived from in vitro studies, for these new series of inhibitors is given.

  15. O-Alkyl Hydroxamates as Metaphors of Enzyme-Bound Enolate Intermediates in Hydroxy Acid Dehydrogenases. Inhibitors of Isopropylmalate Dehydrogenase, Isocitrate Dehydrogenase, and Tartrate Dehydrogenase(1).

    Science.gov (United States)

    Pirrung, Michael C.; Han, Hyunsoo; Chen, Jrlung

    1996-07-12

    The inhibition of Thermus thermophilus isopropylmalate dehydrogenase by O-methyl oxalohydroxamate was studied for comparison to earlier results of Schloss with the Salmonella enzyme. It is a fairly potent (1.2 &mgr;M), slow-binding, uncompetitive inhibitor against isopropylmalate and is far superior to an oxamide (25 mM K(i) competitive) that is isosteric with the ketoisocaproate product of the enzyme. This improvement in inhibition was attributed to its increased NH acidity, which presumably is due to the inductive effect of the hydroxylamine oxygen. This principle was extended to the structurally homologous enzyme isocitrate dehydrogenase from E. coli, for which the compound O-(carboxymethyl) oxalohydroxamate is a 30 nM inhibitor, uncompetitive against isocitrate. The pH dependence of its inhibition supports the idea that it is bound to the enzyme in the anionic form. Another recently discovered homologous enzyme, tartrate dehydrogenase from Pseudomonas putida, was studied with oxalylhydroxamate. It has a relatively low affinity for the enzyme, though it is superior to tartrate. On the basis of these leads, squaric hydroxamates with increased acidity compared to squaric amides directed toward two of these enzymes were prepared, and they also show increased inhibitory potency, though not approaching the nanomolar levels of the oxalylhydroxamates.

  16. Site selection of active damper for stabilizing power electronics based power distribution system

    DEFF Research Database (Denmark)

    Yoon, Changwoo; Wang, Xiongfei; Bak, Claus Leth

    2015-01-01

    electronics based power device, which provides an adjustable damping capability to the power system where the voltage harmonic instability is measured. It can stabilize by adjusting the equivalent node impedance with its plug and play feature. This feature gives many degrees of freedom of its installation......Stability in the nowadays distribution power system is endangered by interaction problems that may arise from newly added power-electronics based power devices. Recently, a new concept to deal with this higher frequency instability, the active damper, has been proposed. The active damper is a power...... point when the system has many nodes. Therefore, this paper addresses the proper placement of an active damper in an unstable small-scale power distribution system. A time-domain model of the Cigre benchmark low-vltage network is used as a test field. The result shows the active damper location...

  17. Effect of Electronic Messaging on Physical Activity Participation among Older Adults

    OpenAIRE

    Antoine Parker, Chantrell; Ellis, Rebecca

    2016-01-01

    The purpose of this study was to determine if electronic messaging would increase min of aerobic physical activity (PA) among older adults. Participants were active older adults (n = 28; M age = 60 years, SD = 5.99, and range = 51?74 years). Using an incomplete within-subjects crossover design, participants were randomly assigned to begin the 4-week study receiving the treatment condition (a morning and evening text message) or the control condition (an evening text message). Participants sel...

  18. Electronic Nose Technology to Measure Soil Microbial Activity and Classify Soil Metabolic Status

    OpenAIRE

    Fabrizio De Cesare; Elena Di Mattia; Simone Pantalei; Emiliano Zampetti; Vittorio Vinciguerra; Antonella Macagnano

    2011-01-01

    The electronic nose (E-nose) is a sensing technology that has been widely used to monitor environments in the last decade. In the present study, the capability of an E-nose, in combination with biochemical and microbiological techniques, of both detecting the microbial activity and estimating the metabolic status of soil ecosystems, was tested by measuring on one side respiration, enzyme activities and growth of bacteria in natural but simplified soil ecosystems over 23 days of incubation thr...

  19. Effect of electron beam-irradiation to b-glucan on its immunomodulating and antitumor activity

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Yeon Hwan; Lee, Jung Lim; Yoo, Yung Choon [Konyand Univ., Daejeon (Korea, Republic of); Kim, Jae Hoon; Lee, Ju Woon [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2010-07-01

    In this study, in order investigated the effect of electron beam irradiation to b-glucan on its biological activities, we compared immunomodulating and antitumor activity between non-irradiated and electron beam-irradiated b-glucan. EB-glucan was irradiated by electron beam with 10, 30 and 50 kGy. Treatment with EB-glucan resulted in a slight increase of the proliferation of ConA-stimulated splenocytes, and the strongest activity was seen in 50 kGy-treated EB-glucan. EB-glucan teated with 50 kGy also showed increased secretion of cytokines such as IL-2 IFN-{gamma} and IL-6 from ConA-stimulated splenocytes. The activity of EB-glucan to enhance the proliferation of splenocytes and cytokine secretion from ConA-stimulated splenocytes was higher than that of NI-glucan. Furthermore, EB-glucan treated with 50 kGy showed higher activity to activate RAW 264.7 macrophages, comparing with that of NI-glucan. In experiments of antitumor activity, EB-glucan treated with 50 kGy prior to tumor inoculation inhibited an experimental lung metastasis produced by B16-BL6 melanoma cells in mice. But NI-glucan did show no effect. In addition, EB-glucan treated with 50 kGy induced a decrease a decrease of tumor growth in tumor-bearing mice. Collectivelt, these results indicates that electron beam irradiation {beta}-glucan leads its biological functions to enhance immunomodulating and antitumor activity.

  20. Effect of electron beam-irradiation to b-glucan on its immunomodulating and antitumor activity

    International Nuclear Information System (INIS)

    Jung, Yeon Hwan; Lee, Jung Lim; Yoo, Yung Choon; Kim, Jae Hoon; Lee, Ju Woon

    2010-01-01

    In this study, in order investigated the effect of electron beam irradiation to b-glucan on its biological activities, we compared immunomodulating and antitumor activity between non-irradiated and electron beam-irradiated b-glucan. EB-glucan was irradiated by electron beam with 10, 30 and 50 kGy. Treatment with EB-glucan resulted in a slight increase of the proliferation of ConA-stimulated splenocytes, and the strongest activity was seen in 50 kGy-treated EB-glucan. EB-glucan teated with 50 kGy also showed increased secretion of cytokines such as IL-2 IFN-γ and IL-6 from ConA-stimulated splenocytes. The activity of EB-glucan to enhance the proliferation of splenocytes and cytokine secretion from ConA-stimulated splenocytes was higher than that of NI-glucan. Furthermore, EB-glucan treated with 50 kGy showed higher activity to activate RAW 264.7 macrophages, comparing with that of NI-glucan. In experiments of antitumor activity, EB-glucan treated with 50 kGy prior to tumor inoculation inhibited an experimental lung metastasis produced by B16-BL6 melanoma cells in mice. But NI-glucan did show no effect. In addition, EB-glucan treated with 50 kGy induced a decrease a decrease of tumor growth in tumor-bearing mice. Collectivelt, these results indicates that electron beam irradiation β-glucan leads its biological functions to enhance immunomodulating and antitumor activity

  1. 12 CFR 7.5003 - Composite authority to engage in electronic activities.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 1 2010-01-01 2010-01-01 false Composite authority to engage in electronic activities. 7.5003 Section 7.5003 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY... itself part of or incidental to the business of banking or is otherwise permissible under Federal law. ...

  2. Active Cooling and Thermal Management of a Downhole Tool Electronics Section

    DEFF Research Database (Denmark)

    Soprani, Stefano; Engelbrecht, Kurt; Just Nørgaard, Anders

    2015-01-01

    combines active and passive cooling techniques, aiming at an efficient thermal management, preserving the tool compactness and avoiding the use of moving parts. Thermoelectric coolers were used to transfer the dissipated heat from the temperature-sensitive electronics to the external environment. Thermal...... contact resistances were minimized and thermally insulating foam protected the refrigerated microenvironment from the hot surroundings....

  3. Single-active-electron potentials for molecules in intense laser fields

    DEFF Research Database (Denmark)

    Abu-Samha, Mahmoud; Madsen, Lars Bojer

    2010-01-01

    Single-active-electron potentials are computed for selected molecules, and molecular wave functions with the correct asymptotic behavior are produced. Asymptotic expansion coefficients are extracted from the wave functions and used to compute alignment-dependent ionization yields from molecular...

  4. THE ENVIRONMENT AND DISTRIBUTION OF EMITTING ELECTRONS AS A FUNCTION OF SOURCE ACTIVITY IN MARKARIAN 421

    International Nuclear Information System (INIS)

    Mankuzhiyil, Nijil; Ansoldi, Stefano; Persic, Massimo; Tavecchio, Fabrizio

    2011-01-01

    For the high-frequency-peaked BL Lac object Mrk 421, we study the variation of the spectral energy distribution (SED) as a function of source activity, from quiescent to active. We use a fully automatized χ 2 -minimization procedure, instead of the 'eyeball' procedure more commonly used in the literature, to model nine SED data sets with a one-zone synchrotron self-Compton (SSC) model and examine how the model parameters vary with source activity. The latter issue can finally be addressed now, because simultaneous broadband SEDs (spanning from optical to very high energy photon) have finally become available. Our results suggest that in Mrk 421 the magnetic field (B) decreases with source activity, whereas the electron spectrum's break energy (γ br ) and the Doppler factor (δ) increase-the other SSC parameters turn out to be uncorrelated with source activity. In the SSC framework, these results are interpreted in a picture where the synchrotron power and peak frequency remain constant with varying source activity, through a combination of decreasing magnetic field and increasing number density of γ ≤ γ br electrons: since this leads to an increased electron-photon scattering efficiency, the resulting Compton power increases, and so does the total (= synchrotron plus Compton) emission.

  5. Efecto de la aplicación de vinazas en las propiedades físicas y la actividad de deshidrogenasas en suelos cultivados con maíz dulce (Zea mays L. Effect of vinasse application on physical properties and dehydrogenases activity in soils under sweet corn (Zea mays L. cultivation

    Directory of Open Access Journals (Sweden)

    Magda Narváez Castillo

    2010-04-01

    Full Text Available Se evaluó el efecto de la aplicación de vinazas en algunas propiedades físicas y en la actividad de las deshidrogenasas en un Entic dystropept y en un Fluventic haplustoll del Valle de Cauca, Colombia. Para suplir los requerimientos de K+ del cultivo de maíz dulce (Zea mays L. se utilizaron seis tratamientos (T1 = 100% de K+ como vinaza, T2 = 100% de K+ con KCl; T3 = 50% de K+ como vinaza y KCl, T4 = 75% de K+ con vinaza y 25% de K+ como KCl, T5 = testigo absoluto sin planta, T6 = testigo más planta que fueron dispuestos en un diseño completamente al azar con cinco repeticiones. En el Entic dystropept la densidad aparente disminuyó y en consecuencia la porosidad total aumentó, mientras que en el Fluventic haplustoll sucedió lo contrario. La actividad de las deshidrogenasas fue significativamente mayor (P The effect of vinasse application was assessed on physical properties and dehydrogenases activity in Entic Dystropept and Fluventic Haplustoll of Valle del Cauca, Colombia. To meet the requirements of K+ in sweet corn (Zea mays L. six treatments were used (T1 = 100% of K+ as vinasse; T2 = 100% of K+ with KCl; T3 = 50% of K+ as vinasse and KCl; T4 = 75% of K+ with vinasse and 25% of K+ as KCl; T5 = absolute control without plants; T6 = control plus plants arranged in a completely randomized design with five replications. In Dystropept Entic bulk density decreased and consequently the total porosity increased, while the opposite happened in Haplustoll Fluventic. The dehydrogenase activity was significantly higher (P <0.05 in the Dystropept Entic than in Haplustoll Fluventic presenting low values. The results showed that the changes that are generated as a result of the application of vinasse are different for each type of soil.

  6. High-throughput screening for cellobiose dehydrogenases by Prussian Blue in situ formation.

    Science.gov (United States)

    Vasilchenko, Liliya G; Ludwig, Roland; Yershevich, Olga P; Haltrich, Dietmar; Rabinovich, Mikhail L

    2012-07-01

    Extracellular fungal flavocytochrome cellobiose dehydrogenase (CDH) is a promising enzyme for both bioelectronics and lignocellulose bioconversion. A selective high-throughput screening assay for CDH in the presence of various fungal oxidoreductases was developed. It is based on Prussian Blue (PB) in situ formation in the presence of cellobiose (<0.25 mM), ferric acetate, and ferricyanide. CDH induces PB formation via both reduction of ferricyanide to ferrocyanide reacting with an excess of Fe³⁺ (pathway 1) and reduction of ferric ions to Fe²⁺ reacting with the excess of ferricyanide (pathway 2). Basidiomycetous and ascomycetous CDH formed PB optimally at pH 3.5 and 4.5, respectively. In contrast to the holoenzyme CDH, its FAD-containing dehydrogenase domain lacking the cytochrome domain formed PB only via pathway 1 and was less active than the parent enzyme. The assay can be applied on active growing cultures on agar plates or on fungal culture supernatants in 96-well plates under aerobic conditions. Neither other carbohydrate oxidoreductases (pyranose dehydrogenase, FAD-dependent glucose dehydrogenase, glucose oxidase) nor laccase interfered with CDH activity in this assay. Applicability of the developed assay for the selection of new ascomycetous CDH producers as well as possibility of the controlled synthesis of new PB nanocomposites by CDH are discussed. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Lactate dehydrogenase inhibition: exploring possible applications beyond cancer treatment.

    Science.gov (United States)

    Di Stefano, Giuseppina; Manerba, Marcella; Di Ianni, Lorenza; Fiume, Luigi

    2016-04-01

    Lactate dehydrogenase (LDH) inhibition is considered a worthwhile attempt in the development of innovative anticancer strategies. Unfortunately, in spite of the involvement of several research institutions and pharma-companies, the discovery of LDH inhibitors with drug-like properties seems a hardly resolvable challenge. While awaiting new advancements, in the present review we will examine other pathologic conditions characterized by increased glycolysis and LDH activity, which could potentially benefit from LDH inhibition. The rationale for targeting LDH activity in these contexts is the same justifying the LDH-based approach in anticancer therapy: because of the enzyme position at the end of glycolytic pathway, LDH inhibitors are not expected to hinder glucose metabolism of normal cells. Moreover, we will summarize the latest contributions in the discovery of enzyme inhibitors and try to glance over the reasons underlying the complexity of this research.

  8. Exploring the Role of Persulfate in the Activation Process: Radical Precursor Versus Electron Acceptor.

    Science.gov (United States)

    Yun, Eun-Tae; Yoo, Ha-Young; Bae, Hyokwan; Kim, Hyoung-Il; Lee, Jaesang

    2017-09-05

    This study elucidates the mechanism behind persulfate activation by exploring the role of various oxyanions (e.g., peroxymonosulfate, periodate, and peracetate) in two activation systems utilizing iron nanoparticle (nFe 0 ) as the reducing agent and single-wall carbon nanotubes (CNTs) as electron transfer mediators. Since the tested oxyanions serve as both electron acceptors and radical precursors in most cases, oxidative degradation of organics was achievable through one-electron reduction of oxyanions on nFe 0 (leading to radical-induced oxidation) and electron transfer mediation from organics to oxyanions on CNTs (leading to oxidative decomposition involving no radical formation). A distinction between degradative reaction mechanisms of the nFe 0 /oxyanion and CNT/oxyanion systems was made in terms of the oxyanion consumption efficacy, radical scavenging effect, and EPR spectral analysis. Statistical study of substrate-specificity and product distribution implied that the reaction route induced on nFe 0 varies depending on the oxyanion (i.e., oxyanion-derived radical), whereas the similar reaction pathway initiates organic oxidation in the CNT/oxyanion system irrespective of the oxyanion type. Chronoamperometric measurements further confirmed electron transfer from organics to oxyanions in the presence of CNTs, which was not observed when applying nFe 0 instead.

  9. Prescribing of Electronic Activity Monitors in Cardiometabolic Diseases: Qualitative Interview-Based Study.

    Science.gov (United States)

    Bellicha, Alice; Macé, Sandrine; Oppert, Jean-Michel

    2017-09-23

    The prevalence of noncommunicable diseases, including those such as type 2 diabetes, obesity, dyslipidemia, and hypertension, so-called cardiometabolic diseases, is high and is increasing worldwide. Strong evidence supports the role of physical activity in management of these diseases. There is general consensus that mHealth technology, including electronic activity monitors, can potentially increase physical activity in patients, but their use in clinical settings remains limited. Practitioners' requirements when prescribing electronic activity monitors have been poorly described. The aims of this qualitative study were (1) to explore how specialist physicians prescribe electronic activity monitors to patients presenting with cardiometabolic conditions, and (2) to better understand their motivation for and barriers to prescribing such monitors. We conducted qualitative semistructured interviews in March to May 2016 with 11 senior physicians from a public university hospital in France with expertise in management of cardiometabolic diseases (type 1 and type 2 diabetes, obesity, hypertension, and dyslipidemia). Interviews lasted 45 to 60 minutes and were audiotaped, transcribed verbatim, and analyzed using directed content analysis. We report our findings following the Consolidated Criteria for Reporting Qualitative Research (COREQ) checklist. Most physicians we interviewed had never prescribed electronic activity monitors, whereas they frequently prescribed blood glucose or blood pressure self-monitoring devices. Reasons for nonprescription included lack of interest in the data collected, lack of evidence for data accuracy, concern about work overload possibly resulting from automatic data transfer, and risk of patients becoming addicted to data. Physicians expected future marketing of easy-to-use monitors that will accurately measure physical activity duration and intensity and provide understandable motivating feedback. Features of electronic activity monitors

  10. Hexose-6-phosphate dehydrogenase contributes to skeletal muscle homeostasis independent of 11β-hydroxysteroid dehydrogenase type 1.

    LENUS (Irish Health Repository)

    Semjonous, Nina M

    2011-01-01

    Glucose-6-phosphate (G6P) metabolism by the enzyme hexose-6-phosphate dehydrogenase (H6PDH) within the sarcoplasmic reticulum lumen generates nicotinamide adenine dinucleotide phosphate (reduced) to provide the redox potential for the enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) to activate glucocorticoid (GC). H6PDH knockout (KO) mice have a switch in 11β-HSD1 activity, resulting in GC inactivation and hypothalamic-pituitary-adrenal axis activation. Importantly, H6PDHKO mice develop a type II fiber myopathy with abnormalities in glucose metabolism and activation of the unfolded protein response (UPR). GCs play important roles in muscle physiology, and therefore, we have examined the importance of 11β-HSD1 and GC metabolism in mediating aspects of the H6PDHKO myopathy. To achieve this, we examined 11β-HSD1\\/H6PDH double-KO (DKO) mice, in which 11β-HSD1 mediated GC inactivation is negated. In contrast to H6PDHKO mice, DKO mice GC metabolism and hypothalamic-pituitary-adrenal axis set point is similar to that observed in 11β-HSD1KO mice. Critically, in contrast to 11β-HSD1KO mice, DKO mice phenocopy the salient features of the H6PDHKO, displaying reduced body mass, muscle atrophy, and vacuolation of type II fiber-rich muscle, fasting hypoglycemia, increased muscle glycogen deposition, and elevated expression of UPR genes. We propose that muscle G6P metabolism through H6PDH may be as important as changes in the redox environment when considering the mechanism underlying the activation of the UPR and the ensuing myopathy in H6PDHKO and DKO mice. These data are consistent with an 11β-HSD1-independent function for H6PDH in which sarcoplasmic reticulum G6P metabolism and nicotinamide adenine dinucleotide phosphate-(oxidized)\\/nicotinamide adenine dinucleotide phosphate (reduced) redox status are important for maintaining muscle homeostasis.

  11. Characterization of Anammox Hydrazine Dehydrogenase, a Key N2-producing Enzyme in the Global Nitrogen Cycle.

    Science.gov (United States)

    Maalcke, Wouter J; Reimann, Joachim; de Vries, Simon; Butt, Julea N; Dietl, Andreas; Kip, Nardy; Mersdorf, Ulrike; Barends, Thomas R M; Jetten, Mike S M; Keltjens, Jan T; Kartal, Boran

    2016-08-12

    Anaerobic ammonium-oxidizing (anammox) bacteria derive their energy for growth from the oxidation of ammonium with nitrite as the electron acceptor. N2, the end product of this metabolism, is produced from the oxidation of the intermediate, hydrazine (N2H4). Previously, we identified N2-producing hydrazine dehydrogenase (KsHDH) from the anammox organism Kuenenia stuttgartiensis as the gene product of kustc0694 and determined some of its catalytic properties. In the genome of K. stuttgartiensis, kustc0694 is one of 10 paralogs related to octaheme hydroxylamine (NH2OH) oxidoreductase (HAO). Here, we characterized KsHDH as a covalently cross-linked homotrimeric octaheme protein as found for HAO and HAO-related hydroxylamine-oxidizing enzyme kustc1061 from K. stuttgartiensis Interestingly, the HDH trimers formed octamers in solution, each octamer harboring an amazing 192 c-type heme moieties. Whereas HAO and kustc1061 are capable of hydrazine oxidation as well, KsHDH was highly specific for this activity. To understand this specificity, we performed detailed amino acid sequence analyses and investigated the catalytic and spectroscopic (electronic absorbance, EPR) properties of KsHDH in comparison with the well defined HAO and kustc1061. We conclude that HDH specificity is most likely derived from structural changes around the catalytic heme 4 (P460) and of the electron-wiring circuit comprising seven His/His-ligated c-type hemes in each subunit. These nuances make HDH a globally prominent N2-producing enzyme, next to nitrous oxide (N2O) reductase from denitrifying microorganisms. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  12. Comparative effects of exposure to high-energy electrons and gamma radiation on active avoidance behaviour

    International Nuclear Information System (INIS)

    Hunt, W.A.

    1983-01-01

    The effect of two types of ionizing radiation was examined on active avoidance behaviour. Male Sprague-Dawley rats were trained to avoid footshock by jumping onto a retractable ledge. When irradiated with high-energy electrons or gamma photons, their performance was degraded in a dose-dependent manner. However, electrons were 1.6 times as effective as gamma photons with ED50s of 62 and 102 Gy, respectively. All animals recovered within 24 min for all doses used. The data suggest that different types of ionizing radiation may not be equivalent when assessing their effect on behaviour. (author)

  13. Electron transport in solid targets and in the active mixture of a CO2 laser amplifier

    Science.gov (United States)

    Galkowski, A.

    The paper examines the use of the NIKE code for the Monte Carlo computation of the deposited energy profile and other characteristics of the absorption process of an electron beam in a solid target and the spatial distribution of primary ionization in the active mixture of a CO2 laser amplifier. The problem is considered in connection with the generation of intense electron beams and the acceleration of thin metal foils, as well as in connection with the electric discharge pumping of a CO2 laser amplifier.

  14. Surface characterization of activated chalcopyrite particles via the FLSmidth ROL process. Part 1: Electron microscope investigations

    DEFF Research Database (Denmark)

    Karcz, Adam Paul; Damø, Anne Juul; Illerup, Jytte Boll

    Because of its unique semiconductor properties, the world’s most abundant copper mineral (chalcopyrite) is refractory with respect to atmospheric leaching using traditional ferric sulfate lixiviants. A novel approach to address this issue – conducted at FLSmidth – utilizes a mechanochemical Rapid...... of copper(II) to dope the semiconductor lattice and thereby "activate" the chalcopyrite, thereby reducing leach times below 2 hours (>98% recovery). Because the activation plays a major role in accelerating the leaching step, it is critical to understand the nature of this intermediate and its part...... in the ROL process. The current work presents results from electron microscope investigations of surface-activated particles....

  15. Toxicological effects of thiomersal and ethylmercury: Inhibition of the thioredoxin system and NADP+-dependent dehydrogenases of the pentose phosphate pathway

    International Nuclear Information System (INIS)

    Rodrigues, Juan; Branco, Vasco; Lu, Jun; Holmgren, Arne; Carvalho, Cristina

    2015-01-01

    Mercury (Hg) is a strong toxicant affecting mainly the central nervous, renal, cardiovascular and immune systems. Thiomersal (TM) is still in use in medical practice as a topical antiseptic and as a preservative in multiple dose vaccines, routinely given to young children in some developing countries, while other forms of mercury such as methylmercury represent an environmental and food hazard. The aim of the present study was to determine the effects of thiomersal (TM) and its breakdown product ethylmercury (EtHg) on the thioredoxin system and NADP + -dependent dehydrogenases of the pentose phosphate pathway. Results show that TM and EtHg inhibited the thioredoxin system enzymes in purified suspensions, being EtHg comparable to methylmercury (MeHg). Also, treatment of neuroblastoma and liver cells with TM or EtHg decreased cell viability (GI 50 : 1.5 to 20 μM) and caused a significant (p < 0.05) decrease in the overall activities of thioredoxin (Trx) and thioredoxin reductase (TrxR) in a concentration- and time-dependent manner in cell lysates. Compared to control, the activities of Trx and TrxR in neuroblastoma cells after EtHg incubation were reduced up to 60% and 80% respectively, whereas in hepatoma cells the reduction was almost 100%. In addition, the activities of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were also significantly inhibited by all mercurials, with inhibition intensity of Hg 2+ > MeHg ≈ EtHg > TM (p < 0.05). Cell incubation with sodium selenite alleviated the inhibitory effects on TrxR and glucose-6-phosphate dehydrogenase. Thus, the molecular mechanism of toxicity of TM and especially of its metabolite EtHg encompasses the blockage of the electrons from NADPH via the thioredoxin system. - Highlights: • TM and EtHg inhibit Trx and TrxR both in purified suspensions and cell lysates. • TM and EtHg also inhibit the activities of G6PDH and 6PGDH in cell lysates, • Co-exposure to selenite alleviates the

  16. Toxicological effects of thiomersal and ethylmercury: Inhibition of the thioredoxin system and NADP{sup +}-dependent dehydrogenases of the pentose phosphate pathway

    Energy Technology Data Exchange (ETDEWEB)

    Rodrigues, Juan, E-mail: juanricardorodrigues@gmail.com [Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa (Portugal); Laboratory of Biochemistry, Faculty of Pharmacy, Central University of Venezuela (Venezuela, Bolivarian Republic of); Branco, Vasco [Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa (Portugal); Lu, Jun; Holmgren, Arne [Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet (Sweden); Carvalho, Cristina, E-mail: cristina.carvalho@ff.ulisboa.pt [Research Institute for Medicines (iMed.ULisboa), Faculty of Pharmacy, Universidade de Lisboa (Portugal)

    2015-08-01

    Mercury (Hg) is a strong toxicant affecting mainly the central nervous, renal, cardiovascular and immune systems. Thiomersal (TM) is still in use in medical practice as a topical antiseptic and as a preservative in multiple dose vaccines, routinely given to young children in some developing countries, while other forms of mercury such as methylmercury represent an environmental and food hazard. The aim of the present study was to determine the effects of thiomersal (TM) and its breakdown product ethylmercury (EtHg) on the thioredoxin system and NADP{sup +}-dependent dehydrogenases of the pentose phosphate pathway. Results show that TM and EtHg inhibited the thioredoxin system enzymes in purified suspensions, being EtHg comparable to methylmercury (MeHg). Also, treatment of neuroblastoma and liver cells with TM or EtHg decreased cell viability (GI{sub 50}: 1.5 to 20 μM) and caused a significant (p < 0.05) decrease in the overall activities of thioredoxin (Trx) and thioredoxin reductase (TrxR) in a concentration- and time-dependent manner in cell lysates. Compared to control, the activities of Trx and TrxR in neuroblastoma cells after EtHg incubation were reduced up to 60% and 80% respectively, whereas in hepatoma cells the reduction was almost 100%. In addition, the activities of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were also significantly inhibited by all mercurials, with inhibition intensity of Hg{sup 2+} > MeHg ≈ EtHg > TM (p < 0.05). Cell incubation with sodium selenite alleviated the inhibitory effects on TrxR and glucose-6-phosphate dehydrogenase. Thus, the molecular mechanism of toxicity of TM and especially of its metabolite EtHg encompasses the blockage of the electrons from NADPH via the thioredoxin system. - Highlights: • TM and EtHg inhibit Trx and TrxR both in purified suspensions and cell lysates. • TM and EtHg also inhibit the activities of G6PDH and 6PGDH in cell lysates, • Co-exposure to selenite alleviates

  17. The yeast complex I equivalent NADH dehydrogenase rescues pink1 mutants.

    Directory of Open Access Journals (Sweden)

    Sven Vilain

    2012-01-01

    Full Text Available Pink1 is a mitochondrial kinase involved in Parkinson's disease, and loss of Pink1 function affects mitochondrial morphology via a pathway involving Parkin and components of the mitochondrial remodeling machinery. Pink1 loss also affects the enzymatic activity of isolated Complex I of the electron transport chain (ETC; however, the primary defect in pink1 mutants is unclear. We tested the hypothesis that ETC deficiency is upstream of other pink1-associated phenotypes. We expressed Saccaromyces cerevisiae Ndi1p, an enzyme that bypasses ETC Complex I, or sea squirt Ciona intestinalis AOX, an enzyme that bypasses ETC Complex III and IV, in pink1 mutant Drosophila and find that expression of Ndi1p, but not of AOX, rescues pink1-associated defects. Likewise, loss of function of subunits that encode for Complex I-associated proteins displays many of the pink1-associated phenotypes, and these defects are rescued by Ndi1p expression. Conversely, expression of Ndi1p fails to rescue any of the parkin mutant phenotypes. Additionally, unlike pink1 mutants, fly parkin mutants do not show reduced enzymatic activity of Complex I, indicating that Ndi1p acts downstream or parallel to Pink1, but upstream or independent of Parkin. Furthermore, while increasing mitochondrial fission or decreasing mitochondrial fusion rescues mitochondrial morphological defects in pink1 mutants, these manipulations fail to significantly rescue the reduced enzymatic activity of Complex I, indicating that functional defects observed at the level of Complex I enzymatic activity in pink1 mutant mitochondria do not arise from morphological defects. Our data indicate a central role for Complex I dysfunction in pink1-associated defects, and our genetic analyses with heterologous ETC enzymes suggest that Ndi1p-dependent NADH dehydrogenase activity largely acts downstream of, or in parallel to, Pink1 but upstream of Parkin and mitochondrial remodeling.

  18. Expression and kinetic properties of a recombinant 3 alpha-hydroxysteroid/dihydrodiol dehydrogenase isoenzyme of human liver.

    Science.gov (United States)

    Deyashiki, Y; Tamada, Y; Miyabe, Y; Nakanishi, M; Matsuura, K; Hara, A

    1995-08-01

    Human liver cytosol contains multiple forms of 3 alpha-hydroxysteroid dehydrogenase and dihydrodiol dehydrogenase with hydroxysteroid dehydrogenase activity, and multiple cDNAs for the enzymes have been cloned from human liver cDNA libraries. To understand the relationship of the multiple enzyme froms to the genes, a cDNA, which has been reported to code for an isoenzyme of human liver 3 alpha-hydroxysteroid/dihydrodiol dehydrogenase, was expressed in Escherichia coli. The recombinant enzyme showed structural and functional properties almost identical to those of the isoenzyme purified from human liver. In addition, the recombinant isoenzyme efficiently reduced 5 alpha-dihydrotestosterone and 5 beta-dihydrocortisone, the known substrates of human liver 3 alpha-hydroxysteroid dehydrogenase and chlordecone reductase previously purified, which suggests that these human liver enzymes are identical. Furthermore, the steady-state kinetic data for NADP(+)-linked (S)-1-indanol oxidation by the recombinant isoenzyme were consistent with a sequential ordered mechanism in which NADP+ binds first. Phenolphthalein inhibited this isoenzyme much more potently than it did the other human liver dihydrodiol dehydrogenases, and was a competitive inhibitor (Ki = 20 nM) that bound to the enzyme-NADP+ complex.

  19. Out of plane distortions of the heme b of Escherichia coli succinate dehydrogenase.

    Directory of Open Access Journals (Sweden)

    Quang M Tran

    Full Text Available The role of the heme b in Escherichia coli succinate dehydrogenase is highly ambiguous and its role in catalysis is questionable. To examine whether heme reduction is an essential step of the catalytic mechanism, we generated a series of site-directed mutations around the heme binding pocket, creating a library of variants with a stepwise decrease in the midpoint potential of the heme from the wild-type value of +20 mV down to -80 mV. This difference in midpoint potential is enough to alter the reactivity of the heme towards succinate and thus its redox state under turnover conditions. Our results show both the steady state succinate oxidase and fumarate reductase catalytic activity of the enzyme are not a function of the redox potential of the heme. As well, lower heme potential did not cause an increase in the rate of superoxide production both in vitro and in vivo. The electron paramagnetic resonance (EPR spectrum of the heme in the wild-type enzyme is a combination of two distinct signals. We link EPR spectra to structure, showing that one of the signals likely arises from an out-of-plane distortion of the heme, a saddled conformation, while the second signal originates from a more planar orientation of the porphyrin ring.

  20. Pyruvate Dehydrogenase Kinase as a Novel Therapeutic Target in Oncology

    Directory of Open Access Journals (Sweden)

    Gopinath eSutendra

    2013-03-01

    Full Text Available Current drug development in oncology is non-selective as it typically focuses on pathways essential for the survival of all dividing cells. The unique metabolic profile of cancer, which is characterized by increased glycolysis and suppressed mitochondrial glucose oxidation provides cancer cells with a proliferative advantage, conducive with apoptosis resistance and even increased angiogenesis. Recent evidence suggests that targeting the cancer-specific metabolic and mitochondrial remodeling may offer selectivity in cancer treatment. Pyruvate dehydrogenase kinase (PDK is a mitochondrial enzyme that is activated in a variety of cancers and results in the selective inhibition of pyruvate dehydrogenase (PDH, a complex of enzymes that converts cytosolic pyruvate to mitochondrial acetyl-CoA, the substrate for the Krebs’ cycle. Inhibition of PDK with either small interfering RNAs or the orphan drug dichloroacetate (DCA shifts the metabolism of cancer cells from glycolysis to glucose oxidation and reverses the suppression of mitochondria-dependent apoptosis. In addition, this therapeutic strategy increases the production of diffusible Krebs’ cycle intermediates and mitochondria-derived reactive oxygen species (mROS, activating p53 or inhibiting pro-proliferative and pro-angiogenic transcription factors like nuclear factor of activated T-cells (NFAT and hypoxia-inducible factor 1α (HIF1α. These effects result in decreased tumor growth and angiogenesis in a variety of cancers with high selectivity. In a small but mechanistic clinical trial in patients with glioblastoma, a highly aggressive and vascular form of brain cancer, DCA decreased tumor angiogenesis and tumor growth, suggesting that metabolic targeting therapies can be translated directly to patients. Therefore, reversing the mitochondrial suppression with metabolic-modulating drugs, like PDK inhibitors holds promise in the rapidly expanding field of metabolic oncology.

  1. Functional consequences of piceatannol binding to glyceraldehyde-3-phosphate dehydrogenase.

    Science.gov (United States)

    Gerszon, Joanna; Serafin, Eligiusz; Buczkowski, Adam; Michlewska, Sylwia; Bielnicki, Jakub Antoni; Rodacka, Aleksandra

    2018-01-01

    Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) is one of the key redox-sensitive proteins whose activity is largely affected by oxidative modifications at its highly reactive cysteine residue in the enzyme's active site (Cys149). Prolonged exposure to oxidative stress may cause, inter alia, the formation of intermolecular disulfide bonds leading to accumulation of GAPDH aggregates and ultimately to cell death. Recently these anomalies have been linked with the pathogenesis of Alzheimer's disease. Novel evidences indicate that low molecular compounds may be effective inhibitors potentially preventing the GAPDH translocation to the nucleus, and inhibiting or slowing down its aggregation and oligomerization. Therefore, we decided to establish the ability of naturally occurring compound, piceatannol, to interact with GAPDH and to reveal its effect on functional properties and selected parameters of the dehydrogenase structure. The obtained data revealed that piceatannol binds to GAPDH. The ITC analysis indicated that one molecule of the tetrameric enzyme may bind up to 8 molecules of polyphenol (7.3 ± 0.9). Potential binding sites of piceatannol to the GAPDH molecule were analyzed using the Ligand Fit algorithm. Conducted analysis detected 11 ligand binding positions. We indicated that piceatannol decreases GAPDH activity. Detailed analysis allowed us to presume that this effect is due to piceatannol ability to assemble a covalent binding with nucleophilic cysteine residue (Cys149) which is directly involved in the catalytic reaction. Consequently, our studies strongly indicate that piceatannol would be an exceptional inhibitor thanks to its ability to break the aforementioned pathologic disulfide linkage, and therefore to inhibit GAPDH aggregation. We demonstrated that by binding with GAPDH piceatannol blocks cysteine residue and counteracts its oxidative modifications, that induce oligomerization and GAPDH aggregation.

  2. Functional consequences of piceatannol binding to glyceraldehyde-3-phosphate dehydrogenase.

    Directory of Open Access Journals (Sweden)

    Joanna Gerszon

    Full Text Available Glyceraldehyde-3-phosphate dehydrogenase (GAPDH is one of the key redox-sensitive proteins whose activity is largely affected by oxidative modifications at its highly reactive cysteine residue in the enzyme's active site (Cys149. Prolonged exposure to oxidative stress may cause, inter alia, the formation of intermolecular disulfide bonds leading to accumulation of GAPDH aggregates and ultimately to cell death. Recently these anomalies have been linked with the pathogenesis of Alzheimer's disease. Novel evidences indicate that low molecular compounds may be effective inhibitors potentially preventing the GAPDH translocation to the nucleus, and inhibiting or slowing down its aggregation and oligomerization. Therefore, we decided to establish the ability of naturally occurring compound, piceatannol, to interact with GAPDH and to reveal its effect on functional properties and selected parameters of the dehydrogenase structure. The obtained data revealed that piceatannol binds to GAPDH. The ITC analysis indicated that one molecule of the tetrameric enzyme may bind up to 8 molecules of polyphenol (7.3 ± 0.9. Potential binding sites of piceatannol to the GAPDH molecule were analyzed using the Ligand Fit algorithm. Conducted analysis detected 11 ligand binding positions. We indicated that piceatannol decreases GAPDH activity. Detailed analysis allowed us to presume that this effect is due to piceatannol ability to assemble a covalent binding with nucleophilic cysteine residue (Cys149 which is directly involved in the catalytic reaction. Consequently, our studies strongly indicate that piceatannol would be an exceptional inhibitor thanks to its ability to break the aforementioned pathologic disulfide linkage, and therefore to inhibit GAPDH aggregation. We demonstrated that by binding with GAPDH piceatannol blocks cysteine residue and counteracts its oxidative modifications, that induce oligomerization and GAPDH aggregation.

  3. Comparison of experimental slant electron content and IRI model for moderate solar activity conditions

    International Nuclear Information System (INIS)

    Cabrera, M.A.; Ezquer, R.G.; Mosert, M.; Jadur, C.A.

    2002-01-01

    The International Reference Ionosphere model only gives the vertical electron content (VTEC). In this paper the slant electron content (SEC) for the ATS 6 satellite - Palehua (21.4 deg. N, 201.9 deg. E) radio signal path for a middle solar activity year is calculated. To this end, IRI model is used to obtain the electron density at different points of the signal path. Equinoxes and solstices are considered. Measurements obtained with Faraday rotation technique at Palehua are compared with the modelled values. Although overestimation was observed for night hours, the results show good SEC predictions for several hours at period of maximum ionisation, suggesting that would be possible to model the STEC using IRI. (author)

  4. Sawtooth activity of the ion cloud in an electron-beam ion trap

    International Nuclear Information System (INIS)

    Radtke, R.; Biedermann, C.

    2003-01-01

    The dynamics of an ensemble of highly charged Ar and Ba ions in an electron-beam ion trap (EBIT) was studied by recording time-resolved x-ray spectra emitted from trapped ions. Sawtoothlike signatures manifest in the spectra for a variety of EBIT operating conditions indicating a sudden collapse of the ion inventory in the trap. The collapse occurs on a time scale of approximately 100 ms and the evolution of the sawteeth is very sensitive to parameters such as electron-beam current and axial trap depth. Analysis of the measurements is based on a time-dependent calculation of the trapping process showing that sawtooth activity is caused by the feedback between the low-Z argon and high-Z barium ions. This unexpected behavior demonstrates the importance of nonlinear effects in electron-beam traps containing more than a single ion species

  5. Behavior change techniques implemented in electronic lifestyle activity monitors: a systematic content analysis.

    Science.gov (United States)

    Lyons, Elizabeth J; Lewis, Zakkoyya H; Mayrsohn, Brian G; Rowland, Jennifer L

    2014-08-15

    Electronic activity monitors (such as those manufactured by Fitbit, Jawbone, and Nike) improve on standard pedometers by providing automated feedback and interactive behavior change tools via mobile device or personal computer. These monitors are commercially popular and show promise for use in public health interventions. However, little is known about the content of their feedback applications and how individual monitors may differ from one another. The purpose of this study was to describe the behavior change techniques implemented in commercially available electronic activity monitors. Electronic activity monitors (N=13) were systematically identified and tested by 3 trained coders for at least 1 week each. All monitors measured lifestyle physical activity and provided feedback via an app (computer or mobile). Coding was based on a hierarchical list of 93 behavior change techniques. Further coding of potentially effective techniques and adherence to theory-based recommendations were based on findings from meta-analyses and meta-regressions in the research literature. All monitors provided tools for self-monitoring, feedback, and environmental change by definition. The next most prevalent techniques (13 out of 13 monitors) were goal-setting and emphasizing discrepancy between current and goal behavior. Review of behavioral goals, social support, social comparison, prompts/cues, rewards, and a focus on past success were found in more than half of the systems. The monitors included a range of 5-10 of 14 total techniques identified from the research literature as potentially effective. Most of the monitors included goal-setting, self-monitoring, and feedback content that closely matched recommendations from social cognitive theory. Electronic activity monitors contain a wide range of behavior change techniques typically used in clinical behavioral interventions. Thus, the monitors may represent a medium by which these interventions could be translated for

  6. Evidence for involvement of medium chain acyl-CoA dehydrogenase in the metabolism of phenylbutyrate.

    Science.gov (United States)

    Kormanik, Kaitlyn; Kang, Heejung; Cuebas, Dean; Vockley, Jerry; Mohsen, Al-Walid

    2012-12-01

    Sodium phenylbutyrate is used for treating urea cycle disorders, providing an alternative for ammonia excretion. Following conversion to its CoA ester, phenylbutyryl-CoA is postulated to undergo one round of β-oxidation to phenylacetyl-CoA, the active metabolite. Molecular modeling suggests that medium chain acyl-CoA dehydrogenase (MCAD; EC 1.3.99.3), a key enzyme in straight chain fatty acid β-oxidation, could utilize phenylbutyryl-CoA as substrate. Moreover, phenylpropionyl-CoA has been shown to be a substrate for MCAD and its intermediates accumulate in patients with MCAD deficiency. We have examined the involvement of MCAD and other acyl-CoA dehydrogenases (ACADs) in the metabolism of phenylbutyryl-CoA. Anaerobic titration of purified recombinant human MCAD with phenylbutyryl-CoA caused changes in the MCAD spectrum that are similar to those induced by octanoyl-CoA, its bona fide substrate, and unique to the development of the charge transfer ternary complex. The calculated apparent dissociation constant (K(D app)) for these substrates was 2.16 μM and 0.12 μM, respectively. The MCAD reductive and oxidative half reactions were monitored using the electron transfer flavoprotein (ETF) fluorescence reduction assay. The catalytic efficiency and the K(m) for phenylbutyryl-CoA were 0.2 mM 34(-1)·sec(-1) and 5.3 μM compared to 4.0 mM(-1)·sec(-1) and 2.8 μM for octanoyl-CoA. Extracts of wild type and MCAD-deficient lymphoblast cells were tested for the ability to reduce ETF using phenylbutyryl-CoA as substrate. While ETF reduction activity was detected in extracts of wild type cells, it was undetectable in extracts of cells deficient in MCAD. The results are consistent with MCAD playing a key role in phenylbutyrate metabolism. Copyright © 2012 Elsevier Inc. All rights reserved.

  7. Neonatal jaundice and glucose-6-phosphate dehydrogenase

    OpenAIRE

    Leite, Amauri Antiquera [UNESP

    2010-01-01

    A deficiência de glicose-6-fosfato desidrogenase em neonatos pode ser a responsável pela icterícia neonatal. Este comentário científico é decorrente do relato sobre o tema publicado neste fascículo e que preocupa diversos autores de outros países em relação às complicações em neonatos de hiperbilirrubinemia, existindo inclusive proposições de alguns autores em incluir o teste para identificar a deficiência de glicose-6-fosfato desidrogenase nos recém-nascidos.Glucose-6-phosphate dehydrogenase...

  8. Are associations between electronic media use and BMI different across levels of physical activity?

    DEFF Research Database (Denmark)

    Melkevik, Ole; Haug, Ellen; Rasmussen, Mette

    2015-01-01

    and girls who did not comply with physical activity guidelines. Among physically active adolescents, EM was found to be significantly associated with BMI or odds for overweight among girls, but not among boys. CONCLUSION: While the usage of EM appear to be inconsequential for BMI and the risk of overweight...... among physically active boys, we find evidence indicating that EM use is associated with BMI and risk for overweight among girls, including those who report complying with MVPA guidelines.......BACKGROUND: The use of electronic media has been found to be a risk factor for higher BMI and for being overweight. Physical activity has been found to be associated with lower BMI and lower risk for being overweight. Little is known about whether the associations between physical activity...

  9. Electronic screens in children's bedrooms and adiposity, physical activity and sleep: do the number and type of electronic devices matter?

    Science.gov (United States)

    Chaput, Jean-Philippe; Leduc, Geneviève; Boyer, Charles; Bélanger, Priscilla; LeBlanc, Allana G; Borghese, Michael M; Tremblay, Mark S

    2014-07-11

    To examine whether the number and type of electronic screens available in children's bedrooms matter in their relationship to adiposity, physical activity and sleep. A cross-sectional study was conducted involving 502 children aged 9-11 years from Ottawa, Ontario. The presence (yes/no) of a television (TV), computer or video game system in the child's bedroom was reported by the parents. Percentage body fat was measured using bioelectrical impedance. An accelerometer was worn over seven days to assess moderate-to-vigorous physical activity (MVPA), total sedentary time, sleep duration and sleep efficiency. Screen time was self-reported by the child. After adjustment for age, sex, ethnicity, annual household income and highest level of parental education, children with 2-3 screens in their bedroom had a significantly higher percentage of body fat than children with no screen in their bedroom. However, while children with 2-3 screens in their bedroom engaged in more screen time overall than those with no screen, total sedentary time and MVPA were not significantly different. Sleep duration was not related to the number of screens in the bedroom, but sleep efficiency was significantly lower in children with at least 2 screens in the bedroom. Finally, children having only a TV in their bedroom had significantly higher adiposity than those having no screen at all. In contrast, the presence of a computer in children's bedrooms was not associated with higher adiposity than that of children with no screen. A higher number of screens in a child's bedroom was associated with higher adiposity, more total screen time and lower sleep efficiency. Having a TV in the bedroom appears to be the type of screen presence associated with higher levels of adiposity. Given the popularity of screens among children, these findings are increasingly relevant to health promotion strategies.

  10. Top-down Fabrication and Enhanced Active Area Electronic Characteristics of Amorphous Oxide Nanoribbons for Flexible Electronics.

    Science.gov (United States)

    Jang, Hyun-June; Joong Lee, Ki; Jo, Kwang-Won; Katz, Howard E; Cho, Won-Ju; Shin, Yong-Beom

    2017-07-18

    Inorganic amorphous oxide semiconductor (AOS) materials such as amorphous InGaZnO (a-IGZO) possess mechanical flexibility and outstanding electrical properties, and have generated great interest for use in flexible and transparent electronic devices. In the past, however, AOS devices required higher activation energies, and hence higher processing temperatures, than organic ones to neutralize defects. It is well known that one-dimensional nanowires tend to have better carrier mobility and mechanical strength along with fewer defects than the corresponding two-dimensional films, but until now it has been difficult, costly, and impractical to fabricate such nanowires in proper alignments by either "bottom-up" growth techniques or by "top-down" e-beam lithography. Here we show a top-down, cost-effective, and scalable approach for the fabrication of parallel, laterally oriented AOS nanoribbons based on lift-off and nano-imprinting. High mobility (132 cm 2 /Vs), electrical stability, and transparency are obtained in a-IGZO nanoribbons, compared to the planar films of the same a-IGZO semiconductor.

  11. Structural Insights into l-Tryptophan Dehydrogenase from a Photoautotrophic Cyanobacterium, Nostoc punctiforme.

    Science.gov (United States)

    Wakamatsu, Taisuke; Sakuraba, Haruhiko; Kitamura, Megumi; Hakumai, Yuichi; Fukui, Kenji; Ohnishi, Kouhei; Ashiuchi, Makoto; Ohshima, Toshihisa

    2017-01-15

    l-Tryptophan dehydrogenase from Nostoc punctiforme NIES-2108 (NpTrpDH), despite exhibiting high amino acid sequence identity (>30%)/homology (>50%) with NAD(P) + -dependent l-Glu/l-Leu/l-Phe/l-Val dehydrogenases, exclusively catalyzes reversible oxidative deamination of l-Trp to 3-indolepyruvate in the presence of NAD + Here, we determined the crystal structure of the apo form of NpTrpDH. The structure of the NpTrpDH monomer, which exhibited high similarity to that of l-Glu/l-Leu/l-Phe dehydrogenases, consisted of a substrate-binding domain (domain I, residues 3 to 133 and 328 to 343) and an NAD + /NADH-binding domain (domain II, residues 142 to 327) separated by a deep cleft. The apo-NpTrpDH existed in an open conformation, where domains I and II were apart from each other. The subunits dimerized themselves mainly through interactions between amino acid residues around the β-1 strand of each subunit, as was observed in the case of l-Phe dehydrogenase. The binding site for the substrate l-Trp was predicted by a molecular docking simulation and validated by site-directed mutagenesis. Several hydrophobic residues, which were located in the active site of NpTrpDH and possibly interacted with the side chain of the substrate l-Trp, were arranged similarly to that found in l-Leu/l-Phe dehydrogenases but fairly different from that of an l-Glu dehydrogenase. Our crystal structure revealed that Met-40, Ala-69, Ile-74, Ile-110, Leu-288, Ile-289, and Tyr-292 formed a hydrophobic cluster around the active site. The results of the site-directed mutagenesis experiments suggested that the hydrophobic cluster plays critical roles in protein folding, l-Trp recognition, and catalysis. Our results provide critical information for further characterization and engineering of this enzyme. In this study, we determined the three-dimensional structure of l-Trp dehydrogenase, analyzed its various site-directed substitution mutants at residues located in the active site, and obtained the

  12. EFFECTS OF PARTIAL HEPATECTOMY, PHENOBARBITAL AND 3-METHYLCHOLANTHRENE ON KINETIC-PARAMETERS OF GLUCOSE-6-PHOSPHATE AND PHOSPHOGLUCONATE DEHYDROGENASE IN-SITU IN PERIPORTAL, INTERMEDIATE AND PERICENTRAL ZONES OF RAT-LIVER LOBULES

    NARCIS (Netherlands)

    Jonges, G. N.; Vogels, I. M. C.; van Noorden, C. J. F.

    1995-01-01

    Glucose-6-phosphate dehydrogenase (G6PDH) and phosphogluconate dehydrogenase (PGDH) are heterogeneously distributed in liver lobules of female rats. The maximum activity of both enzymes is approximately twice higher in intermediate and pericentral zones than in periportal zones. Enzyme activities

  13. Electronic interactions decreasing the activation barrier for the hydrogen electro-oxidation reaction

    International Nuclear Information System (INIS)

    Santos, Elizabeth; Schmickler, Wolfgang

    2008-01-01

    A unified model for electrochemical electron transfer reactions which explicitly accounts for the electronic structure of the electrode recently proposed by us is applied to the hydrogen oxidation reaction at different metal electrocatalysts. We focus on the changes produced in the transition state (saddle point) as a consequence of the interactions with d-bands. We discuss different empirical correlations between properties of the metal and catalytic activity proposed in the past. We show which role is played by the band structure of the different metals and its interaction with the molecule for decreasing the activation barrier. Finally, we demonstrate why some metals are better electrocatalysts for the hydrogen electro-oxidation reaction than others

  14. Calcium inhibition of the NAD+-linked isocitrate dehydrogenase from blowfly flight muscle mitochondria.

    Science.gov (United States)

    Bulos, B A; Thomas, B J; Sacktor, B

    1984-08-25

    Free Ca2+ was shown to inhibit the NAD+-isocitrate dehydrogenase from blowfly flight muscle mitochondria. Inhibition by free Ca2+ concentrations of 40 microM or greater was found in the absence or presence of ADP and citrate, two known activators of the enzyme. Calcium decreased the affinity of the enzyme for its substrate, the magnesium DL-isocitrate chelate; no change in the apparent V of the reaction was observed. Calcium was inhibitory when activity was measured in the presence of fixed concentrations of magnesium DL-isocitrate chelate in the presence of several fixed concentrations of either free isocitrate3-, an activator, or free Mg2+, an inhibitor of the enzyme. That NAD+-isocitrate dehydrogenase from blowfly flight muscle mitochondria was not activated by micromolar free Ca2+ is consistent with the view that calcium does not play a role in regulating the flux through the tricarboxylate cycle in this species.

  15. Latitudinal variation of the topside electron temperature at different levels of solar activity

    Czech Academy of Sciences Publication Activity Database

    Truhlík, Vladimír; Bilitza, D.; Třísková, Ludmila

    2009-01-01

    Roč. 44, č. 6 (2009), s. 693-700 ISSN 0273-1177 R&D Projects: GA AV ČR IAA300420603 Grant - others: NASA (US) NNH06CD17C Institutional research plan: CEZ:AV0Z30420517 Keywords : Electron temperature * Solar activity variation * Latitudinal dependence Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 1.079, year: 2009

  16. Effect of electron-ion treatment on fermentative activity of food yeasts

    International Nuclear Information System (INIS)

    Sergeev, I.N.; Ostapenkov, A.M.

    1988-01-01

    Investigation into effect of electron-ion treatment (EIT) on fermentative activity (FA) of Sacch cerevisial type yeasts of 12 breed was conducted. It is shown that even within the limits of one and the same type different treatment regimes are meded. This is obviously connected with physiologic peculiarities of different yeast breeds. Therefore an individual optimal treatment regime should be determined in each particular case during EIT of different breeds

  17. An electronic implementation for Liao's chaotic delayed neuron model with non-monotonous activation function

    International Nuclear Information System (INIS)

    Duan Shukai; Liao Xiaofeng

    2007-01-01

    A new chaotic delayed neuron model with non-monotonously increasing transfer function, called as chaotic Liao's delayed neuron model, was recently reported and analyzed. An electronic implementation of this model is described in detail. At the same time, some methods in circuit design, especially for circuit with time delayed unit and non-monotonously increasing activation unit, are also considered carefully. We find that the dynamical behaviors of the designed circuits are closely similar to the results predicted by numerical experiments

  18. Effects of whole body x-ray irradiation on induction by phenobarbital of rat liver glucose-6-phosphate dehydrogenase and glutathione reductase

    Energy Technology Data Exchange (ETDEWEB)

    Bitny-Szlachto, S.; Szyszko, A. (Wojskowy Inst. Higieny i Epidemiologii, Warsaw (Poland))

    1979-01-01

    In rats treated with phenobarbital (3x100 mg/kg, i.p.), liver G-6-P dehydrogenase activity increased by 70% in the cytosol and in the 9.000xg supernatant, and only by 20% in microsomes. Moreover, the phenobarbital treatment increased rat liver GSSG reductase activity by 30%. On the other hand, activity of the liver microsomal G-6-P dehydrogenase was found to increase by some 20% in whole body irradiated, both control and phenobarbital treated rats. In rats irradiated with 600 R prior to the first dose of the inducer there was not noted any increase in G-6-P dehydrogenase of the 9.000xg supernatant, and increase in the cytosol activity dropped to 38%. Thus, induction of the soluble liver G-6-P dehydrogenase by phenobarbital has turned out to be radiosensitive, whereas phenobarbital induction of GSSG reductase was unaffected by irradiation.

  19. Electronic states of carbon alloy catalysts and nitrogen substituent effects on catalytic activity

    Science.gov (United States)

    Hata, Tomoyuki; Ushiyama, Hiroshi; Yamashita, Koichi

    2013-03-01

    In recent years, Carbon Alloy Catalysts (CACs) are attracting attention as a candidate for non-platinum-based cathode catalysts in fuel cells. Oxygen reduction reactions at the cathode are divided into two elementary processes, electron transfer and oxygen adsorption. The electron transfer reaction is the rate-determining, and by comparison of energy levels, catalytic activity can be evaluated quantitatively. On the other hand, to begin with, adsorption mechanism is obscure. The purpose of this study is to understand the effect of nitrogen substitution and oxygen adsorption mechanism, by first-principle electronic structure calculations for nitrogen substituted models. To reproduce the elementary processes of oxygen adsorption, we assumed that the initial structures are formed based on the Pauling model, a CACs model and nitrogen substituted CACs models in which various points are replaced with nitrogen. When we try to focus only on the DOS peaks of oxygen, in some substituted model that has high adsorption activity, a characteristic partial occupancy state was found. We conclude that this state will affect the adsorption activity, and discuss on why partially occupied states appear with simplification by using an orbital correlation diagram.

  20. SU-F-T-656: Monte Carlo Study On Air Activation Around a Medical Electron Linac

    International Nuclear Information System (INIS)

    Horst, F; Fehrenbacher, G; Zink, K

    2016-01-01

    Purpose: In high energy photon therapy, several radiation protection issues result from photonuclear reactions. The activation of air - directly by photonuclear reactions as well as indirectly by capture of photoneutrons generated inside the linac head - is a major point of concern for the medical staff. The purpose of this study was to estimate the annual effective dose to medical workers due to activated air around a medical high energy electron linac by means of Monte Carlo simulations. Methods: The treatment head of a Varian Clinac in 18 MV-X mode as well as the surrounding concrete bunker were modeled and the radiation transport was simulated using the Monte Carlo code FLUKA, starting from the primary electron striking the bremsstrahlung target. The activation yields in air from photo-disintegration of O-16 and N-14 nuclei as well as from neutron capture on Ar-40 nuclei were obtained from the simulations. The activation build-up, radioactive decay and air ventilation were studied using a mathematical model. The annual effective dose to workers was estimated by using published isotope specific conversion factors. Results: The oxygen and nitrogen activation yields were in contrast to the argon activation yield found to be field size dependent. The impact of the treatment room ventilation on the different air activation products was investigated and quantified. An estimate with very conservative assumptions gave an annual effective dose to workers of < 1 mSv/a. Conclusion: From the results of this study it can be concluded that the contribution of air activation to the radiation exposure to medical workers should be negligible in modern photon therapy, especially when it is compared to the dose due to prompt neutrons and the activation of heavy solid materials such as the jaws and the collimators inside the linac head.

  1. SU-F-T-656: Monte Carlo Study On Air Activation Around a Medical Electron Linac

    Energy Technology Data Exchange (ETDEWEB)

    Horst, F [Institute of Medical Physics and Radiation Protection, University of Applied Sciences, Giessen (Germany); GSI Helmholtz Centre for Heavy Ion Research, Darmstadt (Germany); Fehrenbacher, G [GSI Helmholtz Centre for Heavy Ion Research, Darmstadt (Germany); Zink, K [Institute of Medical Physics and Radiation Protection, University of Applied Sciences, Giessen (Germany); University Hospital Giessen-Marburg, Marburg (Germany)

    2016-06-15

    Purpose: In high energy photon therapy, several radiation protection issues result from photonuclear reactions. The activation of air - directly by photonuclear reactions as well as indirectly by capture of photoneutrons generated inside the linac head - is a major point of concern for the medical staff. The purpose of this study was to estimate the annual effective dose to medical workers due to activated air around a medical high energy electron linac by means of Monte Carlo simulations. Methods: The treatment head of a Varian Clinac in 18 MV-X mode as well as the surrounding concrete bunker were modeled and the radiation transport was simulated using the Monte Carlo code FLUKA, starting from the primary electron striking the bremsstrahlung target. The activation yields in air from photo-disintegration of O-16 and N-14 nuclei as well as from neutron capture on Ar-40 nuclei were obtained from the simulations. The activation build-up, radioactive decay and air ventilation were studied using a mathematical model. The annual effective dose to workers was estimated by using published isotope specific conversion factors. Results: The oxygen and nitrogen activation yields were in contrast to the argon activation yield found to be field size dependent. The impact of the treatment room ventilation on the different air activation products was investigated and quantified. An estimate with very conservative assumptions gave an annual effective dose to workers of < 1 mSv/a. Conclusion: From the results of this study it can be concluded that the contribution of air activation to the radiation exposure to medical workers should be negligible in modern photon therapy, especially when it is compared to the dose due to prompt neutrons and the activation of heavy solid materials such as the jaws and the collimators inside the linac head.

  2. Measurement of the enzymes lactate dehydrogenase and creatine kinase using reflectance spectroscopy and reagent strips.

    OpenAIRE

    Stevens, J F; Tsang, W; Newall, R G

    1983-01-01

    Two new methods for the assay of total activities of lactate dehydrogenase and creatine kinase are described, in which the enzyme activities are measured from a solid-state reagent strip during a kinetic reaction, the reaction being monitored in the ultra-violet region of the spectrum by reflectance spectroscopy. The performances of these methods are evaluated, and compared to conventional "wet" chemistry methods. The solid-phase reagent methods demonstrated precision and accuracy acceptable ...

  3. Stable shRNA Silencing of Lactate Dehydrogenase A (LDHA) in Human MDA-MB-231 Breast Cancer Cells Fails to Alter Lactic Acid Production, Glycolytic Activity, ATP or Survival.

    Science.gov (United States)

    Mack, Nzinga; Mazzio, Elizabeth A; Bauer, David; Flores-Rozas, Hernan; Soliman, Karam F A

    2017-03-01

    In the US, African Americans have a high death rate from triple-negative breast cancer (TNBC), characterized by lack of hormone receptors (ER, PR, HER2/ERRB2) which are otherwise valuable targets of chemotherapy. There is a need to identify novel targets that negatively impact TNBC tumorigenesis. TNBCs release an abundance of lactic acid, under normoxic, hypoxic and hyperoxic conditions; this referred to as the Warburg effect. Accumulated lactic acid sustains peri-cellular acidity which propels metastatic invasion and malignant aggressive transformation. The source of lactic acid is believed to be via conversion of pyruvate by lactate dehydrogenase (LDH) in the last step of glycolysis, with most studies focusing on the LDHA isoform. In this study, LDHA was silenced using long-term MISSION® shRNA lentivirus in human breast cancer MDA-MB-231 cells. Down-regulation of LDHA transcription and protein expression was confirmed by western blot, immunocytochemistry and qPCR. A number of parameters were measured in fully viable vector controls versus knock-down (KD) clones, including levels of lactic acid produced, glucose consumed, ATP and basic metabolic rates. The data show that lentivirus V-165 generated a knock-down clone most effective in reducing both gene and protein levels to less than 1% of vector controls. Stable KD showed absolutely no changes in cell viability, lactic acid production, ATP, glucose consumption or basic metabolic rate. Given the complete absence of impact on any observed parameter by LDH-A KD and this being somewhat contrary to findings in the literature, further analysis was required to determine why. Whole-transcriptome analytic profile on MDA-MB-231 for LDH subtypes using Agilent Human Genome 4×44k microarrays, where the data show the following component breakdown. Transcripts: 30.47 % LDHA, 69.36% LDHB, 0.12% LDHC and 0.05% LDHD. These findings underscore the importance of alternative isoforms of LDH in cancer cells to produce lactic acid

  4. SERUM ACTIVITIES OF ASPARTATE AMINOTRANSFERASE, CREATINE KINASE AND LACTATE DEHYDROGENASE IN HORSES WITH COLIC ATIVIDADE SÉRICA DAS ENZIMAS ASPARTATO AMINOTRANSFERASE, CREATINA QUINASE E LACTATO DESIDROGENASE EM EQÜINOS COM CÓLICA

    Directory of Open Access Journals (Sweden)

    Aureo Evangelista Santana

    2008-12-01

    Full Text Available Seventy equines distributed in two experimental groups were used, G1 (20 healthy equines, and G2 (50 equines with colic. Blood samples were obtained by jugular vein puncture in ten different moments. The variables aspartate aminotransferase (AST, creatine kinase (CK, and lactate dehydrogenase (LDH were determined by spectrophotometric assay using specific reagents. The average values presented by the animals of the G2 for variables CK, AST, and LDH were higher (P<0.05 than the values presented by the animals of the G1 in all the evaluation moments. The results showed for G2 animals suggest the existence of acute muscle injury. The muscle injuries in equines with colic were attributed to the tissue hypoperfusion, and the muscular damage.

    KEY WORDS: Acute abdomen, horses, muscles enzyme. De setenta eqüinos, distribuídos em dois grupos experimentais – G1 (vinte eqüinos hígidos e G2 (cinqüenta eqüinos com cólica –, colheram-se amostras de sangue em dez diferentes momentos, mediante punção da jugular, para a determinação da atividade sérica das enzimas aspartato aminotransferase (AST, creatina quinase (CK e lactato desidrogenase (LDH. Os valores médios apresentados pelos animais do G2, para as variáveis CK, AST e LDH, foram superiores (P<0,05 aos valores médios apresentados pelos animais do G1 em todos os momentos de avaliação. Os resultados apresentados pelos animais com cólica (G2 sugerem a existência de lesão muscular aguda, porém com tendência a cura, e foram atribuídos a hipoperfusão tecidual e a traumas musculares. A análise seriada das enzimas CK, AST e LDH auxilia tanto no diagnóstico de lesões musculares em eqüinos com cólica como no acompanhamento da evolução do processo de cura.

    PALAVRAS-CHAVES: Abdômen agudo, cavalos, enzimas musculares.

  5. The problem of large samples. An activation analysis study of electronic waste material

    International Nuclear Information System (INIS)

    Segebade, C.; Goerner, W.; Bode, P.

    2007-01-01

    Large-volume instrumental photon activation analysis (IPAA) was used for the investigation of shredded electronic waste material. Sample masses from 1 to 150 grams were analyzed to obtain an estimate of the minimum sample size to be taken to achieve a representativeness of the results which is satisfactory for a defined investigation task. Furthermore, the influence of irradiation and measurement parameters upon the quality of the analytical results were studied. Finally, the analytical data obtained from IPAA and instrumental neutron activation analysis (INAA), both carried out in a large-volume mode, were compared. Only parts of the values were found in satisfactory agreement. (author)

  6. Four-electron transfer tandem tetracyanoquinodimethane for cathode-active material in lithium secondary battery

    Science.gov (United States)

    Kurimoto, Naoya; Omoda, Ryo; Mizumo, Tomonobu; Ito, Seitaro; Aihara, Yuichi; Itoh, Takahito

    2018-02-01

    Quinoid compounds are important candidates of organic active materials for lithium-ion batteries. However, its high solubility to organic electrolyte solutions and low redox potential are known as their major drawbacks. To circumvent these issues, we have designed and synthesized a tandem-tetracyanoquinonedimethane type cathode-active material, 11,11,12,12,13,13,14,14-octacyano-1,4,5,8-anthradiquinotetramethane (OCNAQ), that has four redox sites per molecule, high redox potential and suppressed solubility to electrolyte solution. Synthesized OCNAQ has been found to have two-step redox reactions by cyclic voltammetry, and each step consists of two-electron reactions. During charge-discharge tests using selected organic cathode-active materials with a lithium metal anode, the cell voltages obtained from OCNAQ are higher than those for 11,11-dicyanoanthraquinone methide (AQM) as expected, due to the strong electron-withdrawing effect of the cyano groups. Unfortunately, even with the use of the organic active material, the issue of dissolution to the electrolyte solution cannot be suppressed completely; however, appropriate choice of the electrolyte solutions, glyme-based electrolyte solutions in this study, give considerable improvement of the cycle retention (98% and 56% at 10 and 100 cycles at 0.5C, respectively). The specific capacity and energy density obtained in this study are 206 mAh g-1 and 554 mWh g-1 with respect to the cathode active material.

  7. Vitamin-responsive complex I deficiency in a myopathic patient with increased activity of the terminal respiratory chain and lactic acidosis

    NARCIS (Netherlands)

    Bakker, H. D.; Scholte, H. R.; Jeneson, J. A.; Busch, H. F.; Abeling, N. G.; van Gennip, A. H.

    1994-01-01

    An 11-year-old girl with exercise intolerance, fatiguability from early childhood, had high blood lactate levels. Histochemistry showed increased activity of succinate dehydrogenase at the periphery of the muscle fibres, whereas aggregates of mitochondria were seen by electron microscopy.

  8. Wakefields generated by electron beams passing through a waveguide loaded with a slightly dispersive active medium

    Directory of Open Access Journals (Sweden)

    Andrey V. Tyukhtin

    2007-05-01

    Full Text Available The wakefields of a relativistic electron beam passing through a waveguide loaded with an active medium with weak resonant dispersion are considered. For the calculations in this paper, the parameters of the medium are those of a solution of fullerene (C_{60} in a nematic liquid crystal that exhibits activity in the X-band. It is shown that several of the TM accelerating modes can be amplified for the geometries under consideration; structures in which higher order modes are amplified exhibit essential advantages as PASERs. In particular, the amplification of the highest mode occurs in a structure loaded with a rather thick active medium layer that maximizes the energy stored by the active medium.

  9. Detailed characteristics of radiation belt electrons revealed by CSSWE/REPTile measurements: Geomagnetic activity response and precipitation observation

    Science.gov (United States)

    Zhang, K.; Li, X.; Schiller, Q.; Gerhardt, D.; Zhao, H.; Millan, R.

    2017-08-01

    Earth's outer radiation belt electrons are highly dynamic. We study the detailed characteristics of relativistic electrons in the outer belt using measurements from the Colorado Student Space Weather Experiment (CSSWE) mission, a low Earth orbit (LEO) CubeSat, which traverses the radiation belt four times in one orbit ( 1.5 h) and has the advantage of measuring the dynamic activities of the electrons including their rapid precipitation. We focus on the measured electron response to geomagnetic activity for different energies to show that there are abundant sub-MeV electrons in the inner belt and slot region. These electrons are further enhanced during active times, while there is a lack of >1.63 MeV electrons in these regions. We also show that the variation of measured electron flux at LEO is strongly dependent on the local magnetic field strength, which is far from a dipole approximation. Moreover, a specific precipitation band, which happened on 19 January 2013, is investigated based on the conjunctive measurement of CSSWE, the Balloon Array for Radiation belt Relativistic Electron Losses, and one of the Polar Operational Environmental Satellites. In this precipitation band event, the net loss of the 0.58-1.63 MeV electrons (L = 3.5-6) is estimated to account for 6.8% of the total electron content.

  10. Quantitative comparison between the gel-film and polyvinyl alcohol methods for dehydrogenase histochemistry reveals different intercellular distribution patterns of glucose-6-phosphate and lactate dehydrogenases in mouse liver

    NARCIS (Netherlands)

    Griffini, P.; Vigorelli, E.; Bertone, V.; Freitas, I.; van Noorden, C. J.

    1994-01-01

    The precise histochemical localization and quantification of the activity of soluble dehydrogenases in unfixed cryostat sections requires the use of tissue protectants. In this study, two protectants, polyvinyl alcohol (PVA) and agarose gel, were compared for assaying the activity of lactate

  11. Enzymatic urea adaptation: lactate and malate dehydrogenase in elasmobranchs

    Czech Academy of Sciences Publication Activity Database

    Lagana, G.; Bellocco, E.; Mannucci, C.; Leuzzi, U.; Tellone, E.; Kotyk, Arnošt; Galtieri, A.

    2006-01-01

    Roč. 55, č. 6 (2006), s. 675-688 ISSN 0862-8408 Institutional research plan: CEZ:AV0Z50110509 Keywords : elasmobranchs * lactate dehydrogenase * malate dehydrogenase Subject RIV: CE - Biochemistry Impact factor: 2.093, year: 2006

  12. Lactate dehydrogenase is not a mitochondrial enzyme in human and mouse vastus lateralis muscle

    DEFF Research Database (Denmark)

    Rasmussen, Hans N; van Hall, Gerrit; Rasmussen, Ulla F

    2002-01-01

    The presence of lactate dehydrogenase in skeletal muscle mitochondria was investigated to clarify whether lactate is a possible substrate for mitochondrial respiration. Mitochondria were prepared from 100 mg samples of human and mouse vastus lateralis muscle. All fractions from the preparation...... procedure were assayed for marker enzymes and lactate dehydrogenase (LDH). The mitochondrial fraction contained no LDH activity (detection limit approximately 0.05 % of the tissue activity) and the distribution of LDH activity among the fractions paralleled that of pyruvate kinase, i.e. LDH was fractionated...... as a cytoplasmic enzyme. Respiratory experiments with the mitochondrial fraction also indicated the absence of LDH. Lactate did not cause respiration, nor did it affect the respiration of pyruvate + malate. The major part of the native cytochrome c was retained in the isolated mitochondria, which, furthermore...

  13. Regulation of pyruvate dehydrogenase kinase expression by the farnesoid X receptor

    International Nuclear Information System (INIS)

    Savkur, Rajesh S.; Bramlett, Kelli S.; Michael, Laura F.; Burris, Thomas P.

    2005-01-01

    The pyruvate dehydrogenase complex (PDC) functions as an important junction in intermediary metabolism by influencing the utilization of fat versus carbohydrate as a source of fuel. Activation of PDC is achieved by phosphatases, whereas, inactivation is catalyzed by pyruvate dehydrogenase kinases (PDKs). The expression of PDK4 is highly regulated by the glucocorticoid and peroxisome proliferator-activated receptors. We demonstrate that the farnesoid X receptor (FXR; NR1H4), which regulates a variety of genes involved in lipoprotein metabolism, also regulates the expression of PDK4. Treatment of rat hepatoma cells as well as human primary hepatocytes with FXR agonists stimulates the expression of PDK4 to levels comparable to those obtained with glucocorticoids. In addition, treatment of mice with an FXR agonist significantly increased hepatic PDK4 expression, while concomitantly decreasing plasma triglyceride levels. Thus, activation of FXR may suppress glycolysis and enhance oxidation of fatty acids via inactivation of the PDC by increasing PDK4 expression

  14. Effect of electron beam irradiation on conidial germination activity and pathogenicity of Botrytis cinerea

    International Nuclear Information System (INIS)

    Zhang Ting; Qiao Yongjin; Chen Zhaoliang

    2011-01-01

    Conidia of Botrytis cinerea were irradiated by electron beam at 0.5, 1.0, 2.0 and 3.0 kGy. The influence of electron beam on the activities of conidial germination and pathogenicity at the temperatures of 5 ℃ and 25 ℃ were tested, respectively. The results showed that the electron beam could inhibit germination of conidia and the length of germ tube of Botrytis cinerea, and delay the germination time. It could also decrease the pathogenicity obviously and higher irradiation dose showed stronger effects. Compared with control, the complete germination time of conidia extended to 5 and 9 d at the cultivate temperatures of 25 ℃ and 5 ℃, after 2 kGy of irradiation, and the germination rate was reduced 46.57% and 33.68%, respectively. The inhibition rates of germ tube were 25.12% and 74.29% when cultured 24 h. The pathogenicity of Botrytis cinerea to strawberry was reduced significantly. After 2.0 kGy irradiation and cultivate at 25 ℃ for 2 d, the disease index was 4.17 and it decreased to 15.28 after cultivation of 5 ℃ for 15 d. Electron beam treatment could inhibit the spore germination and germ tube elongation of Botrytis cinerea significantly, delayed the germination time, and reduced its pathogenicity, the higher the dose, the effect was more obvious. (authors)

  15. Electronic Structure Control of Tungsten Oxide Activated by Ni for Ultrahigh-Performance Supercapacitors.

    Science.gov (United States)

    Meng, Tian; Kou, Zongkui; Amiinu, Ibrahim Saana; Hong, Xufeng; Li, Qingwei; Tang, Yongfu; Zhao, Yufeng; Liu, Shaojun; Mai, Liqiang; Mu, Shichun

    2018-04-17

    Tuning the electron structure is of vital importance for designing high active electrode materials. Here, for boosting the capacitive performance of tungsten oxide, an atomic scale engineering approach to optimize the electronic structure of tungsten oxide by Ni doping is reported. Density functional theory calculations disclose that through Ni doping, the density of state at Fermi level for tungsten oxide can be enhanced, thus promoting its electron transfer. When used as electrode of supercapacitors, the obtained Ni-doped tungsten oxide with 4.21 at% Ni exhibits an ultrahigh mass-specific capacitance of 557 F g -1 at the current density of 1 A g -1 and preferable durability in a long-term cycle test. To the best of knowledge, this is the highest supercapacitor performance reported so far in tungsten oxide and its composites. The present strategy demonstrates the validity of the electronic structure control in tungsten oxide via introducing Ni atoms for pseudocapacitors, which can be extended to other related fields as well. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Effects of Home Access to Active Videogames on Child Self-Esteem, Enjoyment of Physical Activity, and Anxiety Related to Electronic Games: Results from a Randomized Controlled Trial.

    Science.gov (United States)

    Abbott, Rebecca A; Smith, Anne J; Howie, Erin K; Pollock, Clare; Straker, Leon

    2014-08-01

    Active-input videogames could provide a useful conduit for increasing physical activity by improving a child's self-confidence, physical activity enjoyment, and reducing anxiety. Therefore this study evaluated the impact of (a) the removal of home access to traditional electronic games or (b) their replacement with active-input videogames, on child self-perception, enjoyment of physical activity, and electronic game use anxiety. This was a crossover, randomized controlled trial, conducted over a 6-month period in participants' family homes in metropolitan Perth, Australia, from 2007 to 2010. Children 10-12 years old were recruited through school and community media. Of 210 children who were eligible, 74 met inclusion criteria, and 8 withdrew, leaving 66 children (33 girls) for analysis. A counterbalanced randomized order of three conditions sustained for 8 weeks each: No home access to electronic games, home access to traditional electronic games, and home access to active-input electronic games. Perception of self-esteem (Harter's Self Perception Profile for Children), enjoyment of physical activity (Physical Activity Enjoyment Scale questionnaire), and anxiety toward electronic game use (modified Loyd and Gressard Computer Anxiety Subscale) were assessed. Compared with home access to traditional electronic games, neither removal of all electronic games nor replacement with active-input games resulted in any significant change to child self-esteem, enjoyment of physical activity, or anxiety related to electronic games. Although active-input videogames have been shown to be enjoyable in the short term, their ability to impact on psychological outcomes is yet to be established.

  17. Conductance and activation energy for electron transport in series and parallel intramolecular circuits.

    Science.gov (United States)

    Hsu, Liang-Yan; Wu, Ning; Rabitz, Herschel

    2016-11-30

    We investigate electron transport through series and parallel intramolecular circuits in the framework of the multi-level Redfield theory. Based on the assumption of weak monomer-bath couplings, the simulations depict the length and temperature dependence in six types of intramolecular circuits. In the tunneling regime, we find that the intramolecular circuit rule is only valid in the weak monomer coupling limit. In the thermally activated hopping regime, for circuits based on two different molecular units M a and M b with distinct activation energies E act,a > E act,b , the activation energies of M a and M b in series are nearly the same as E act,a while those in parallel are nearly the same as E act,b . This study gives a comprehensive description of electron transport through intramolecular circuits from tunneling to thermally activated hopping. We hope that this work can motivate additional studies to design intramolecular circuits based on different types of building blocks, and to explore the corresponding circuit laws and the length and temperature dependence of conductance.

  18. Light-Enhanced Antibacterial Activity of Graphene Oxide, Mainly via Accelerated Electron Transfer.

    Science.gov (United States)

    Chong, Yu; Ge, Cuicui; Fang, Ge; Wu, Renfei; Zhang, He; Chai, Zhifang; Chen, Chunying; Yin, Jun-Jie

    2017-09-05

    Before graphene derivatives can be exploited as next-generation antimicrobials, we must understand their behavior under environmental conditions. Here, we demonstrate how exposure to simulated sunlight significantly enhances the antibacterial activity of graphene oxide (GO) and reveal the underlying mechanism. Our measurements of reactive oxygen species (ROS) showed that only singlet oxygen ( 1 O 2 ) is generated by GO exposed to simulated sunlight, which contributes only slightly to the oxidation of antioxidant biomolecules. Unexpectedly, we find the main cause of oxidation is light-induced electron-hole pairs generated on the surface of GO. These light-induced electrons promote the reduction of GO, introducing additional carbon-centered free radicals that may also enhance the antibacterial activities of GO. We conclude that GO-mediated oxidative stress mainly is ROS-independent; simulated sunlight accelerates the transfer of electrons from antioxidant biomolecules to GO, thereby destroying bacterial antioxidant systems and causing the reduction of GO. Our insights will help support the development of graphene for antibacterial applications.

  19. Misfit Strain in Superlattices Controlling the Electron-Lattice Interaction via Micro strain in Active Layers

    International Nuclear Information System (INIS)

    Poccia, N.; Ricci, A.; Bianconi, N.

    2010-01-01

    High-temperature superconductivity (HTS) emerges in quite different electronic materials: cuprates, diborides, and iron-pnictide superconductors. Looking for unity in the diversity we find in all these materials a common lattice architecture: they are practical realizations of heterostructures at atomic limit made of superlattices of metallic active layers intercalated by spacers as predicted in 1993 by one of us. The multilayer architecture is the key feature for the presence of electronic topological transitions where the Fermi surface of one of the subbands changes dimensionality. The superlattice misfit strain η between the active and spacer layers is shown to be a key variable to drive the system to the highest critical temperature Tc that occurs at a particular point of the 3D phase diagram Tc(θ, η) where d is the charge transfer or doping. The plots of Tc as a function of misfit strain at constant charge transfer in cuprates show a first-order quantum critical phase transition where an itinerant striped magnetic phase competes with superconductivity in the proximity of a structural phase transition, that is, associated with an electronic topological transition. The shape resonances in these multi gap superconductors is associated with the maximum Tc.

  20. The effects of storage on the retention of enzyme activity in cryostat sections. A quantitative histochemical study on rat liver

    NARCIS (Netherlands)

    Frederiks, W. M.; Ouwerkerk, I. J.; Bosch, K. S.; Marx, F.; Kooij, A.; van Noorden, C. J.

    1993-01-01

    The effect of storage of unfixed cryostat sections from rat liver for 4 h, 24 h, 3 days and 7 days at -25 degrees C was studied on the activities of lactate dehydrogenase, glucose-6-phosphate dehydrogenase, xanthine oxidoreductase, glutamate dehydrogenase, succinate dehydrogenase (all demonstrated

  1. Automatic prediction of rheumatoid arthritis disease activity from the electronic medical records.

    Directory of Open Access Journals (Sweden)

    Chen Lin

    Full Text Available We aimed to mine the data in the Electronic Medical Record to automatically discover patients' Rheumatoid Arthritis disease activity at discrete rheumatology clinic visits. We cast the problem as a document classification task where the feature space includes concepts from the clinical narrative and lab values as stored in the Electronic Medical Record.The Training Set consisted of 2792 clinical notes and associated lab values. Test Set 1 included 1749 clinical notes and associated lab values. Test Set 2 included 344 clinical notes for which there were no associated lab values. The Apache clinical Text Analysis and Knowledge Extraction System was used to analyze the text and transform it into informative features to be combined with relevant lab values.Experiments over a range of machine learning algorithms and features were conducted. The best performing combination was linear kernel Support Vector Machines with Unified Medical Language System Concept Unique Identifier features with feature selection and lab values. The Area Under the Receiver Operating Characteristic Curve (AUC is 0.831 (σ = 0.0317, statistically significant as compared to two baselines (AUC = 0.758, σ = 0.0291. Algorithms demonstrated superior performance on cases clinically defined as extreme categories of disease activity (Remission and High compared to those defined as intermediate categories (Moderate and Low and included laboratory data on inflammatory markers.Automatic Rheumatoid Arthritis disease activity discovery from Electronic Medical Record data is a learnable task approximating human performance. As a result, this approach might have several research applications, such as the identification of patients for genome-wide pharmacogenetic studies that require large sample sizes with precise definitions of disease activity and response to therapies.

  2. Metagenomic insight into methanogenic reactors promoting direct interspecies electron transfer via granular activated carbon.

    Science.gov (United States)

    Park, Jeong-Hoon; Park, Jong-Hun; Je Seong, Hoon; Sul, Woo Jun; Jin, Kang-Hyun; Park, Hee-Deung

    2018-07-01

    To provide insight into direct interspecies electron transfer via granular activated carbon (GAC), the effect of GAC supplementation on anaerobic digestion was evaluated. Compared to control samples, the GAC supplementation increased the total amount of methane production and its production rate by 31% and 72%, respectively. 16S rDNA sequencing analysis revealed a shift in the archaeal community composition; the Methanosarcina proportion decreased 17%, while the Methanosaeta proportion increased 5.6%. Metagenomic analyses based on shotgun sequencing demonstrated that the abundance of pilA and omcS genes belonging to Geobacter species decreased 69.4% and 29.4%, respectively. Furthermore, the analyses suggested a carbon dioxide reduction pathway rather than an acetate decarboxylation pathway for methane formation. Taken together, these results suggest that GAC improved methane production performance by shifting the microbial community and altering functional genes associated with direct interspecies electron transfer via conductive materials. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Antimycobacterial and Photosynthetic Electron Transport Inhibiting Activity of Ring-Substituted 4-Arylamino-7-Chloroquinolinium Chlorides

    Directory of Open Access Journals (Sweden)

    Alois Cizek

    2013-09-01

    Full Text Available In this study, a series of twenty-five ring-substituted 4-arylamino-7-chloroquinolinium chlorides were prepared and characterized. The compounds were tested for their activity related to inhibition of photosynthetic electron transport (PET in spinach (Spinacia oleracea L. chloroplasts and also primary in vitro screening of the synthesized compounds was performed against mycobacterial species. 4-[(2-Bromophenylamino]-7-chloroquinolinium chloride showed high biological activity against M. marinum, M. kansasii, M. smegmatis and 7-chloro-4-[(2-methylphenylamino]quinolinium chloride demonstrated noteworthy biological activity against M. smegmatis and M. avium subsp. paratuberculosis. The most effective compounds demonstrated quite low toxicity (LD50 > 20 μmol/L against the human monocytic leukemia THP-1 cell line within preliminary in vitro cytotoxicity screening. The tested compounds were found to inhibit PET in photosystem II. The PET-inhibiting activity expressed by IC50 value of the most active compound 7-chloro-4-[(3-trifluoromethylphenylamino]quinolinium chloride was 27 μmol/L and PET-inhibiting activity of ortho-substituted compounds was significantly lower than this of meta- and para-substituted ones. The structure-activity relationships are discussed for all compounds.

  4. Development of microalgae biomaterials with enhanced antioxidant activity using electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Younghwa; Park, Hyunjin; Choi, Soojeong; Lee, Jaehwa [Silla Univ., Busan (Korea, Republic of)

    2013-07-01

    By increasing the antioxidant products (e. g. antioxidant enzyme, carotenoid, phycobiliproteins, chlorophyll, lipid phenolic compounds, etc.) in microalgae, it could be useful for industry. In this study, mutants of fresh water microalgae Arthrospira platensis (A. platensis) by high energy electron beam were isolated and characterized. Those selected mutants showed higher growth rate than parental strain. The antioxidant enzyme activity (SOD and POD), flavonoid, phenolic compound and phycocyanin of mutants were increased about 2 times compared to wild type. Moreover, DPPH radical scavenging activity was increased about 20%. Microalgae species with improved growth rate and enhanced active compounds make the commercial process more feasible in industry. Using microalgae mutants with increased antioxidant products, it is useful to develop microalgae biomaterials for neutraceuticals.

  5. Development of microalgae biomaterials with enhanced antioxidant activity using electron beam

    International Nuclear Information System (INIS)

    Kim, Younghwa; Park, Hyunjin; Choi, Soojeong; Lee, Jaehwa

    2013-01-01

    By increasing the antioxidant products (e. g. antioxidant enzyme, carotenoid, phycobiliproteins, chlorophyll, lipid phenolic compounds, etc.) in microalgae, it could be useful for industry. In this study, mutants of fresh water microalgae Arthrospira platensis (A. platensis) by high energy electron beam were isolated and characterized. Those selected mutants showed higher growth rate than parental strain. The antioxidant enzyme activity (SOD and POD), flavonoid, phenolic compound and phycocyanin of mutants were increased about 2 times compared to wild type. Moreover, DPPH radical scavenging activity was increased about 20%. Microalgae species with improved growth rate and enhanced active compounds make the commercial process more feasible in industry. Using microalgae mutants with increased antioxidant products, it is useful to develop microalgae biomaterials for neutraceuticals

  6. Pitch angle distributions of electrons at dipolarization sites during geomagnetic activity: THEMIS observations

    Science.gov (United States)

    Wang, Kaiti; Lin, Ching-Huei; Wang, Lu-Yin; Hada, Tohru; Nishimura, Yukitoshi; Turner, Drew L.; Angelopoulos, Vassilis

    2014-12-01

    Changes in pitch angle distributions of electrons with energies from a few eV to 1 MeV at dipolarization sites in Earth's magnetotail are investigated statistically to determine the extent to which adiabatic acceleration may contribute to these changes. Forty-two dipolarization events from 2008 and 2009 observed by Time History of Events and Macroscale Interactions during Substorms probes covering the inner plasma sheet from 8 RE to 12 RE during geomagnetic activity identified by the AL index are analyzed. The number of observed events with cigar-type distributions (peaks at 0° and 180°) decreases sharply below 1 keV after dipolarization because in many of these events, electron distributions became more isotropized. From above 1 keV to a few tens of keV, however, the observed number of cigar-type events increases after dipolarization and the number of isotropic events decreases. These changes can be related to the ineffectiveness of Fermi acceleration below 1 keV (at those energies, dipolarization time becomes comparable to electron bounce time). Model-calculated pitch angle distributions after dipolarization with the effect of betatron and Fermi acceleration tested indicate that these adiabatic acceleration mechanisms can explain the observed patterns of event number changes over a large range of energies for cigar events and isotropic events. Other factors still need to be considered to assess the observed increase in cigar events around 2 keV. Indeed, preferential directional increase/loss of electron fluxes, which may contribute to the formation of cigar events, was observed. Nonadiabatic processes to accelerate electrons in a parallel direction may also be important for future study.

  7. Enantiocomplementary Yarrowia lipolytica Oxidoreductases: Alcohol Dehydrogenase 2 and Short Chain Dehydrogenase/Reductase

    Directory of Open Access Journals (Sweden)

    Margit Winkler

    2013-08-01

    Full Text Available Enzymes of the non-conventional yeast Yarrowia lipolytica seem to be tailor-made for the conversion of lipophilic substrates. Herein, we cloned and overexpressed the Zn-dependent alcohol dehydrogenase ADH2 from Yarrowia lipolytica in Escherichia coli. The purified enzyme was characterized in vitro. The substrate scope for YlADH2 mediated oxidation and reduction was investigated spectrophotometrically and the enzyme showed a broader substrate range than its homolog from Saccharomyces cerevisiae. A preference for secondary compared to primary alcohols in oxidation direction was observed for YlADH2. 2-Octanone was investigated in reduction mode in detail. Remarkably, YlADH2 displays perfect (S-selectivity and together with a highly (R-selective short chain dehydrogenase/ reductase from Yarrowia lipolytica it is possible to access both enantiomers of 2-octanol in >99% ee with Yarrowia lipolytica oxidoreductases.

  8. Enantiocomplementary Yarrowia lipolytica Oxidoreductases: Alcohol Dehydrogenase 2 and Short Chain Dehydrogenase/Reductase.

    Science.gov (United States)

    Napora-Wijata, Kamila; Strohmeier, Gernot A; Sonavane, Manoj N; Avi, Manuela; Robins, Karen; Winkler, Margit

    2013-08-12

    Enzymes of the non-conventional yeast Yarrowia lipolytica seem to be tailor-made for the conversion of lipophilic substrates. Herein, we cloned and overexpressed the Zn-dependent alcohol dehydrogenase ADH2 from Yarrowia lipolytica in Escherichia coli. The purified enzyme was characterized in vitro. The substrate scope for YlADH2 mediated oxidation and reduction was investigated spectrophotometrically and the enzyme showed a broader substrate range than its homolog from Saccharomyces cerevisiae. A preference for secondary compared to primary alcohols in oxidation direction was observed for YlADH2. 2-Octanone was investigated in reduction mode in detail. Remarkably, YlADH2 displays perfect (S)-selectivity and together with a highly (R)-selective short chain dehydrogenase/ reductase from Yarrowia lipolytica it is possible to access both enantiomers of 2-octanol in >99% ee with Yarrowia lipolytica oxidoreductases.

  9. Overexpression of Lactobacillus casei D-hydroxyisocaproic acid dehydrogenase in cheddar cheese.

    Science.gov (United States)

    Broadbent, Jeffery R; Gummalla, Sanjay; Hughes, Joanne E; Johnson, Mark E; Rankin, Scott A; Drake, Mary Anne

    2004-08-01

    Metabolism of aromatic amino acids by lactic acid bacteria is an important source of off-flavor compounds in Cheddar cheese. Previous work has shown that alpha-keto acids produced from Trp, Tyr, and Phe by aminotransferase enzymes are chemically labile and may degrade spontaneously into a variety of off-flavor compounds. However, dairy lactobacilli can convert unstable alpha-keto acids to more-stable alpha-hydroxy acids via the action of alpha-keto acid dehydrogenases such as d-hydroxyisocaproic acid dehydrogenase. To further characterize the role of this enzyme in cheese flavor, the Lactobacillus casei d-hydroxyisocaproic acid dehydrogenase gene was cloned into the high-copy-number vector pTRKH2 and transformed into L. casei ATCC 334. Enzyme assays confirmed that alpha-keto acid dehydrogenase activity was significantly higher in pTRKH2:dhic transformants than in wild-type cells. Reduced-fat Cheddar cheeses were made with Lactococcus lactis starter only, starter plus L. casei ATCC 334, and starter plus L. casei ATCC 334 transformed with pTRKH2:dhic. After 3 months of aging, the cheese chemistry and flavor attributes were evaluated instrumentally by gas chromatography-mass spectrometry and by descriptive sensory analysis. The culture system used significantly affected the concentrations of various ketones, aldehydes, alcohols, and esters and one sulfur compound in cheese. Results further indicated that enhanced expression of d-hydroxyisocaproic acid dehydrogenase suppressed spontaneous degradation of alpha-keto acids, but sensory work indicated that this effect retarded cheese flavor development.

  10. CdWO4 polymorphs: Selective preparation, electronic structures, and photocatalytic activities

    International Nuclear Information System (INIS)

    Yan, Tingjiang; Li, Liping; Tong, Wenming; Zheng, Jing; Wang, Yunjian; Li, Guangshe

    2011-01-01

    This work explored the selective synthesis of polymorphs of CdWO 4 in either tetragonal or monoclinic phase by optimizing the experimental parameters. Systematic characterization indicated that both polymorphs possessed similar spherical morphologies but different structural building blocks. Electronic structures calculations for both polymorphs demonstrated the same constructions of conduction band or valence band, while the conduction band widths of both polymorphs were quite different. Both CdWO 4 polymorphs exhibited good photocatalytic activity for degradation of methyl orange under UV light irradiation. When comparing to some other well-known tungstate oxide materials, the photocatalytic activity was found to follow such a consequence, monoclinic CdWO 4 ∼monoclinic ZnWO 4 >tetragonal CdWO 4 >tetragonal CaWO 4 . The specific photocatalytic activity of monoclinic CdWO 4 was even higher than that of commercial TiO 2 photocatalyst (Degussa P25). The increased activity from the tetragonal CdWO 4 to the monoclinic was consistent with the trend of the decreased symmetry, and this could be explained in terms of the geometric structures and electronic structures for both polymorphs. -- Graphical abstract: Monoclinic CdWO 4 exhibited a much higher photocatalytic activity than the tetragonal form owing to the lower symmetry, more distorted geometric structure, and the dispersive band configuration. Display Omitted Research highlights: → Polymorphs of CdWO 4 in either tetragonal or monoclinic phase were selectively synthesized. → Both polymorphs possessed similar spherical morphologies, while the relevant structural building blocks were different. → Photocatalytic activities of CdWO 4 polymorphs depended strongly on the symmetry, geometric structure, as well as band configuration.

  11. Enantiocomplementary Yarrowia lipolytica Oxidoreductases: Alcohol Dehydrogenase 2 and Short Chain Dehydrogenase/Reductase

    OpenAIRE

    Napora-Wijata, Kamila; Strohmeier, Gernot A.; Sonavane, Manoj N.; Avi, Manuela; Robins, Karen; Winkler, Margit

    2013-01-01

    Enzymes of the non-conventional yeast Yarrowia lipolytica seem to be tailor-made for the conversion of lipophilic substrates. Herein, we cloned and overexpressed the Zn-dependent alcohol dehydrogenase ADH2 from Yarrowia lipolytica in Escherichia coli. The purified enzyme was characterized in vitro. The substrate scope for YlADH2 mediated oxidation and reduction was investigated spectrophotometrically and the enzyme showed a broader substrate range than its homolog from Saccharomyces cerevisia...

  12. Over-Expression, Purification and Crystallization of Human Dihydrolipoamide Dehydrogenase

    Science.gov (United States)

    Hong, Y. S.; Ciszak, Ewa; Patel, Mulchand

    2000-01-01

    Dehydrolipoamide dehydrogenase (E3; dihydrolipoan-tide:NAD+ oxidoreductase, EC 1.8.1.4) is a common catalytic component found in pyruvate dehydrogenase complex, alpha-ketoglutarate dehydrogenase complex, and branched-chain cc-keto acid dehydrogenase complex. E3 is also a component (referred to as L protein) of the glycine cleavage system in bacterial metabolism (2). Active E3 forms a homodimer with four distinctive subdomain structures (FAD binding, NAD+ binding, central and interface domains) with non-covalently but tightly bound FAD in the holoenzyme. Deduced amino acids from cloned full-length human E3 gene showed a total of 509 amino acids with a leader sequence (N-terminal 35 amino acids) that is excised (mature form) during transportation of expressed E3 into mitochondria membrane. So far, three-dimensional structure of human E3 has not been reported. Our effort to achieve the elucidation of the X-ray crystal structure of human E3 will be presented. Recombinant pPROEX-1 expression vector (from GIBCO BRL Life Technologies) having the human E3 gene without leader sequence was constructed by Polymerase Chain Reaction (PCR) and subsequent ligation, and cloned in E.coli XL1-Blue by transformation. Since pPROEX-1 vector has an internal His-tag (six histidine peptide) located at the upstream region of a multicloning site, one-step affinity purification of E3 using nickelnitriloacetic acid (Ni-NTA) agarose resin, which has a strong affinity to His-tag, was feasible. Also a seven-amino-acid spacer peptide and a recombinant tobacco etch virus protease recognition site (seven amino acids peptide) found between His-tag and first amino acid of expressed E3 facilitated the cleavage of His-tag from E3 after the affinity purification. By IPTG induction, ca. 15 mg of human E3 (mature form) was obtained from 1L LB culture with overnight incubation at 25C. Over 98% of purity of E3 from one-step Ni-NTA agarose affinity purification was confirmed by SDS-PAGE analysis. For

  13. The patients' active role in managing a personal electronic health record: a qualitative analysis.

    Science.gov (United States)

    Baudendistel, Ines; Winkler, Eva; Kamradt, Martina; Brophy, Sarah; Längst, Gerda; Eckrich, Felicitas; Heinze, Oliver; Bergh, Bjoern; Szecsenyi, Joachim; Ose, Dominik

    2015-09-01

    The complexity of illness and cross-sectoral health care pose challenges for patients with colorectal cancer and their families. Within a patient-centered care paradigm, it is vital to give patients the opportunity to play an active role. Prospective users' attitudes regarding the patients' role in the context of a patient-controlled electronic health record (PEPA) were explored. A qualitative study across regional health care settings and health professions was conducted. Overall, 10 focus groups were performed collecting views of 3 user groups: patients with colorectal cancer (n = 12) and representatives from patient support groups (n = 2), physicians (n = 17), and other health care professionals (HCPs) (n = 16). Data were audio- and videotaped, transcribed verbatim and thematically analyzed using qualitative content analysis. The patients' responsibility as a gatekeeper and access manager was at the center of the focus group discussions, although HCPs addressed aspects that would limit patients taking an active role (e.g., illness related issues). Despite expressed concerns, PEPAs possibility to enhance personal responsibility was seen in all user groups. Giving patients an active role in managing a personal electronic health record is an innovative patient-centered approach, although existing restraints have to be recognized. To enhance user adoption and advance PEPAs potential, key user needs have to be addressed.

  14. Multiple alcohol dehydrogenases but no functional acetaldehyde dehydrogenase causing excessive acetaldehyde production from ethanol by oral streptococci.

    Science.gov (United States)

    Pavlova, Sylvia I; Jin, Ling; Gasparovich, Stephen R; Tao, Lin

    2013-07-01

    Ethanol consumption and poor oral hygiene are risk factors for oral and oesophageal cancers. Although oral streptococci have been found to produce excessive acetaldehyde from ethanol, little is known about the mechanism by which this carcinogen is produced. By screening 52 strains of diverse oral streptococcal species, we identified Streptococcus gordonii V2016 that produced the most acetaldehyde from ethanol. We then constructed gene deletion mutants in this strain and analysed them for alcohol and acetaldehyde dehydrogenases by zymograms. The results showed that S. gordonii V2016 expressed three primary alcohol dehydrogenases, AdhA, AdhB and AdhE, which all oxidize ethanol to acetaldehyde, but their preferred substrates were 1-propanol, 1-butanol and ethanol, respectively. Two additional dehydrogenases, S-AdhA and TdhA, were identified with specificities to the secondary alcohol 2-propanol and threonine, respectively, but not to ethanol. S. gordonii V2016 did not show a detectable acetaldehyde dehydrogenase even though its adhE gene encodes a putative bifunctional acetaldehyde/alcohol dehydrogenase. Mutants with adhE deletion showed greater tolerance to ethanol in comparison with the wild-type and mutant with adhA or adhB deletion, indicating that AdhE is the major alcohol dehydrogenase in S. gordonii. Analysis of 19 additional strains of S. gordonii, S. mitis, S. oralis, S. salivarius and S. sanguinis showed expressions of up to three alcohol dehydrogenases, but none showed detectable acetaldehyde dehydrogenase, except one strain that showed a novel ALDH. Therefore, expression of multiple alcohol dehydrogenases but no functional acetaldehyde