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Sample records for formaldehyde dehydrogenase role

  1. Enhanced Formaldehyde Detoxification by Overexpression of Glutathione-Dependent Formaldehyde Dehydrogenase from Arabidopsis1

    PubMed Central

    Achkor, Hakima; Díaz, Maykelis; Fernández, M. Rosario; Biosca, Josep Antoni; Parés, Xavier; Martínez, M. Carmen

    2003-01-01

    The ADH2 gene codes for the Arabidopsis glutathione-dependent formaldehyde dehydrogenase (FALDH), an enzyme involved in formaldehyde metabolism in eukaryotes. In the present work, we have investigated the potential role of FALDH in detoxification of exogenous formaldehyde. We have generated a yeast (Saccharomyces cerevisiae) mutant strain (sfa1Δ) by in vivo deletion of the SFA1 gene that codes for the endogenous FALDH. Overexpression of Arabidopsis FALDH in this mutant confers high resistance to formaldehyde added exogenously, which demonstrates the functional conservation of the enzyme through evolution and supports its essential role in formaldehyde metabolism. To investigate the role of the enzyme in plants, we have generated Arabidopsis transgenic lines with modified levels of FALDH. Plants overexpressing the enzyme show a 25% increase in their efficiency to take up exogenous formaldehyde, whereas plants with reduced levels of FALDH (due to either a cosuppression phenotype or to the expression of an antisense construct) show a marked slower rate and reduced ability for formaldehyde detoxification as compared with the wild-type Arabidopsis. These results show that the capacity to take up and detoxify high concentrations of formaldehyde is proportionally related to the FALDH activity in the plant, revealing the essential role of this enzyme in formaldehyde detoxification. PMID:12913179

  2. Formaldehyde dehydrogenase preparations from Methylococcus capsulatus (Bath) comprise methanol dehydrogenase and methylene tetrahydromethanopterin dehydrogenase.

    PubMed

    Adeosun, Ekundayo K; Smith, Thomas J; Hoberg, Anne-Mette; Velarde, Giles; Ford, Robert; Dalton, Howard

    2004-03-01

    In methylotrophic bacteria, formaldehyde is an important but potentially toxic metabolic intermediate that can be assimilated into biomass or oxidized to yield energy. Previously reported was the purification of an NAD(P)(+)-dependent formaldehyde dehydrogenase (FDH) from the obligate methane-oxidizing methylotroph Methylococcus capsulatus (Bath), presumably important in formaldehyde oxidation, which required a heat-stable factor (known as the modifin) for FDH activity. Here, the major protein component of this FDH preparation was shown by biophysical techniques to comprise subunits of 64 and 8 kDa in an alpha(2)beta(2) arrangement. N-terminal sequencing of the subunits of FDH, together with enzymological characterization, showed that the alpha(2)beta(2) tetramer was a quinoprotein methanol dehydrogenase of the type found in other methylotrophs. The FDH preparations were shown to contain a highly active NAD(P)(+)-dependent methylene tetrahydromethanopterin dehydrogenase that was the probable source of the NAD(P)(+)-dependent formaldehyde oxidation activity. These results support previous findings that methylotrophs possess multiple pathways for formaldehyde dissimilation. PMID:14993320

  3. Structure-Function Relationships in Human Glutathione-Dependent Formaldehyde Dehydrogenase. Role of Glu-67 and Arg-368 in the Catalytic Mechanism

    SciTech Connect

    Sanghani,P.; Davis, W.; Zhai, L.; Robinson, H.

    2006-01-01

    The active-site zinc in human glutathione-dependent formaldehyde dehydrogenase (FDH) undergoes coenzyme-induced displacement and transient coordination to a highly conserved glutamate residue (Glu-67) during the catalytic cycle. The role of this transient coordination of the active-site zinc to Glu-67 in the FDH catalytic cycle and the associated coenzyme interactions were investigated by studying enzymes in which Glu-67 and Arg-368 were substituted with Leu. Structures of FDH{center_dot}adenosine 5'-diphosphate ribose (ADP-ribose) and E67L{center_dot}NAD(H) binary complexes were determined. Steady-state kinetics, isotope effects, and presteady-state analysis of the E67L enzyme show that Glu-67 is critical for capturing the substrates for catalysis. The catalytic efficiency (V/Km) of the E67L enzyme in reactions involving S-nitrosoglutathione (GSNO), S-hydroxymethylglutathione (HMGSH) and 12-hydroxydodecanoic acid (12-HDDA) were 25 000-, 3000-, and 180-fold lower, respectively, than for the wild-type enzyme. The large decrease in the efficiency of capturing GSNO and HMGSH by the E67L enzyme results mainly because of the impaired binding of these substrates to the mutant enzyme. In the case of 12-HDDA, a decrease in the rate of hydride transfer is the major factor responsible for the reduction in the efficiency of its capture for catalysis by the E67L enzyme. Binding of the coenzyme is not affected by the Glu-67 substitution. A partial displacement of the active-site zinc in the FDH{center_dot}ADP-ribose binary complex indicates that the disruption of the interaction between Glu-67 and Arg-368 is involved in the displacement of active-site zinc. Kinetic studies with the R368L enzyme show that the predominant role of Arg-368 is in the binding of the coenzyme. An isomerization of the ternary complex before hydride transfer is detected in the kinetic pathway of HMGSH. Steps involved in the binding of the coenzyme to the FDH active site are also discerned from the

  4. Membrane-Associated Quinoprotein Formaldehyde Dehydrogenase from Methylococcus capsulatus Bath

    PubMed Central

    Zahn, James A.; Bergmann, David J.; Boyd, Jeffery M.; Kunz, Ryan C.; DiSpirito, Alan A.

    2001-01-01

    A membrane-associated, dye-linked formaldehyde dehydrogenase (DL-FalDH) was isolated from the obligate methylotroph Methylococcus capsulatus Bath. The enzyme was the major formaldehyde-oxidizing enzyme in cells cultured in high (above 1 μmol of Cu per mg of cell protein) copper medium and expressing the membrane-associated methane monooxygenase. Soluble NAD(P)+-linked formaldehyde oxidation was the major activity in cells cultured in low-copper medium and expressing the soluble methane monooxygenase (Tate and Dalton, Microbiology 145:159–167, 1999; Vorholt et al., J. Bacteriol. 180:5351–5356, 1998). The membrane-associated enzyme is a homotetramer with a subunit molecular mass of 49,500 Da. UV-visible absorption, electron paramagnetic resonance, and electrospray mass spectrometry suggest the redox cofactor of the DL-FalDH is pyrroloquinoline quinone (PQQ), with a PQQ-to-subunit stochiometry of approximately 1:1. The enzyme was specific for formaldehyde, oxidizing formaldehyde to formate, and utilized the cytochrome b559/569 complex as the physiological electron acceptor. PMID:11698372

  5. Membrane-associated quinoprotein formaldehyde dehydrogenase from Methylococcus capsulatus Bath.

    PubMed

    Zahn, J A; Bergmann, D J; Boyd, J M; Kunz, R C; DiSpirito, A A

    2001-12-01

    A membrane-associated, dye-linked formaldehyde dehydrogenase (DL-FalDH) was isolated from the obligate methylotroph Methylococcus capsulatus Bath. The enzyme was the major formaldehyde-oxidizing enzyme in cells cultured in high (above 1 micromol of Cu per mg of cell protein) copper medium and expressing the membrane-associated methane monooxygenase. Soluble NAD(P)(+)-linked formaldehyde oxidation was the major activity in cells cultured in low-copper medium and expressing the soluble methane monooxygenase (Tate and Dalton, Microbiology 145:159-167, 1999; Vorholt et al., J. Bacteriol. 180:5351-5356, 1998). The membrane-associated enzyme is a homotetramer with a subunit molecular mass of 49,500 Da. UV-visible absorption, electron paramagnetic resonance, and electrospray mass spectrometry suggest the redox cofactor of the DL-FalDH is pyrroloquinoline quinone (PQQ), with a PQQ-to-subunit stochiometry of approximately 1:1. The enzyme was specific for formaldehyde, oxidizing formaldehyde to formate, and utilized the cytochrome b(559/569) complex as the physiological electron acceptor. PMID:11698372

  6. A low-molecular-mass protein from Methylococcus capsulatus (Bath) is responsible for the regulation of formaldehyde dehydrogenase activity in vitro.

    PubMed

    Tate, S; Dalton, H

    1999-01-01

    An 8.6 kDa protein, which the authors call a modifin, has been purified from Methylococcus capsulatus (Bath) and has been shown to alter the substrate specificity and kinetics of NAD+-linked formaldehyde dehydrogenase (FDH) isolated from the same organism. Purification methods for both the modifin and FDH are presented which reliably produced pure protein for further analysis. Analysis of the molecular mass and N-terminal sequence of both FDH and the modifin indicate that they are unique proteins and show no similarity to alcohol or aldehyde dehydrogenase enzymes isolated from methylotrophic bacteria. Substrate specificity studies demonstrated that FDH oxidized formaldehyde exclusively in the presence of the modifin; a diverse range of aldehydes and alcohols were oxidized by FDH in the absence of the modifin. No formaldehyde oxidation was detected in the absence of the modifin. Attempts to replace the modifin with glutathione or high concentrations of methanol to stimulate formaldehyde oxidation failed. With acetaldehyde as substrate, FDH showed standard Michaelis-Menten kinetics; interaction of FDH with the modifin using formaldehyde as substrate altered the kinetics of the reaction to sigmoidal. Kinetic analysis during turnover experiments indicated that the FDH may be associated with bound formaldehyde following enzyme isolation and that NAD may also be associated with the enzyme but in a form that is less tightly bound than found with the methanol dehydrogenase from Bacillus methanolicus. Data are presented which indicate that the modifin may play an important role in regulating formaldehyde concentration in vivo. PMID:10206695

  7. Mutation of Arg-115 of human class III alcohol dehydrogenase: a binding site required for formaldehyde dehydrogenase activity and fatty acid activation.

    PubMed Central

    Engeland, K; Höög, J O; Holmquist, B; Estonius, M; Jörnvall, H; Vallee, B L

    1993-01-01

    The origin of the fatty acid activation and formaldehyde dehydrogenase activity that distinguishes human class III alcohol dehydrogenase (alcohol:NAD+ oxidoreductase, EC 1.1.1.1) from all other alcohol dehydrogenases has been examined by site-directed mutagenesis of its Arg-115 residue. The Ala- and Asp-115 mutant proteins were expressed in Escherichia coli and purified by affinity chromatography and ion-exchange HPLC. The activities of the recombinant native and mutant enzymes toward ethanol are essentially identical, but mutagenesis greatly decreases the kcat/Km values for glutathione-dependent formaldehyde oxidation. The catalytic efficiency for the Asp variant is < 0.1% that of the unmutated enzyme, due to both a higher Km and a lower kcat value. As with the native enzyme, neither mutant can oxidize methanol, be saturated by ethanol, or be inhibited by 4-methylpyrazole; i.e., they retain these class III characteristics. In contrast, however, their activation by fatty acids, another characteristic unique to class III alcohol dehydrogenase, is markedly attenuated. The Ala mutant is activated only slightly, but the Asp mutant is not activated at all. The results strongly indicate that Arg-115 in class III alcohol dehydrogenase is a component of the binding site for activating fatty acids and is critical for the binding of S-hydroxymethylglutathione in glutathione-dependent formaldehyde dehydrogenase activity. PMID:8460164

  8. Formaldehyde.

    PubMed

    Pontén, Ann; Bruze, Magnus

    2015-01-01

    Formaldehyde is the American Contact Dermatitis Society Contact Allergen of the Year for 2015. The exposure is widespread, and contact allergy might be difficult to suspect in the individual dermatitis patient. The relevance of contact allergy to formaldehyde might also be difficult to evaluate. Recently, however, several studies have been performed aimed at enhancing the patch test technique and evaluating the clinical relevance of contact allergy to formaldehyde. The patch test concentration of formaldehyde has been recommended by the European Environmental Contact Dermatitis Research Group to be 2.0%, that is, the dose of 0.60 mg/cm (wt/vol) instead of 1.0%, which is the concentration previously used for the baseline series in most countries. Without causing any more irritant reactions, the patch test concentration of 2.0% detects twice as many contact allergies and enables the diagnosis of formaldehyde-allergic patients who otherwise would have been missed. The studies that underpin the decision were performed in Europe and partly in the United States. The Finn Chamber patch test system was used. The allergen dose per area was kept uniform with a micropipette. This report describes the background for routinely using formaldehyde 2.0% instead of 1.0% and for using a micropipette when applying the test solution. PMID:25581665

  9. Formaldehyde

    Integrated Risk Information System (IRIS)

    Formaldehyde ; CASRN 50 - 00 - 0 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic Effec

  10. Microbial Formaldehyde Oxidation

    SciTech Connect

    Timothy J. Donohue

    2004-12-09

    This project analyzed how cells sense and generate energy from formaldehyde oxidation. Formaldehyde is a toxin that is produced naturally, chemically or by metabolism of a wide variety of methyl-containing compounds. Our goals are to identify how cells sense the presence of this toxic compound and determine how they generate energy and nutrients from the oxidation of formaldehyde. This research capitalizes on the role of the Rhodobacter sphaeroides glutathione dependent formaldehyde dehydrogenase (GSH FDH) in a formaldehyde oxidation pathway that is apparently found in a wide variety of microbes, plants and animals. Thus, our findings illustrate what is required for a large variety of cells to metabolize this toxic compound. A second major focus of our research is to determine how cells sense the presence of this toxic compound and control the expression of gene products required for its detoxification.

  11. Purification and properties of S-hydroxymethylglutathione dehydrogenase of Paecilomyces variotii no. 5, a formaldehyde-degrading fungus

    PubMed Central

    2012-01-01

    S-hydroxymethylglutathione dehydrogenase from Paecilomyces variotii No. 5 strain (NBRC 109023), isolated as a formaldehyde-degrading fungus, was purified by a procedure that included ammonium sulfate precipitation, DEAE-Sepharose and hydroxyapatite chromatography and isoelectrofocusing. Approximately 122-fold purification was achieved with a yield of 10.5%. The enzyme preparation was homogeneous as judged by sodium dodecyl polyacrylamide gel electrophoresis (SDS-PAGE). The molecular mass of the purified enzyme was estimated to be 49 kDa by SDS-PAGE and gel filtration, suggesting that it is a monomer. Enzyme activity was optimal at pH 8.0 and was stable in the range of pH 7.0–10. The optimum temperature for activity was 40°C and the enzyme was stable up to 40°C. The isoelectric point was pH 5.8. Substrate specificity was very high for formaldehyde. Besides formaldehyde, the only aldehyde or alcohol tested that served as a substrate was pyruvaldehyde. Enzyme activity was enhanced by several divalent cations such as Mn2+ (179%), Ba2+ (132%), and Ca2+ (112%) but was completely inhibited by Ni2+, Fe3+, Hg2+, p-chloromercuribenzoate (PCMB) and cuprizone. Inactivation of the enzyme by sulfhydryl reagents (Hg2+ and PCMB) indicated that the sulfhydryl group of the enzyme is essential for catalytic activity. PMID:22731626

  12. Cloning of the Arabidopsis and Rice Formaldehyde Dehydrogenase Genes: Implications for the Origin of Plant Adh Enzymes

    PubMed Central

    Dolferus, R.; Osterman, J. C.; Peacock, W. J.; Dennis, E. S.

    1997-01-01

    This article reports the cloning of the genes encoding the Arabidopsis and rice class III ADH enzymes, members of the alcohol dehydrogenase or medium chain reductase/dehydrogenase superfamily of proteins with glutathione-dependent formaldehyde dehydrogenase activity (GSH-FDH). Both genes contain eight introns in exactly the same positions, and these positions are conserved in plant ethanol-active Adh genes (class P). These data provide further evidence that plant class P genes have evolved from class III genes by gene duplication and acquisition of new substrate specificities. The position of introns and similarities in the nucleic acid and amino acid sequences of the different classes of ADH enzymes in plants and humans suggest that plant and animal class III enzymes diverged before they duplicated to give rise to plant and animal ethanol-active ADH enzymes. Plant class P ADH enzymes have gained substrate specificities and evolved promoters with different expression properties, in keeping with their metabolic function as part of the alcohol fermentation pathway. PMID:9215914

  13. IDENTIFICATION OF THE ROLE OF APOPTOSIS PATHWAYS POTENTIALLY INVOLVED IN FORMALDEHYDE-INDUCED CARCINOGENESIS USING CDNA ARRAYS

    EPA Science Inventory

    Identification of the Role of Apoptosis Pathways Potentially Involved in Formaldehyde- Induced Carcinogenesis Using cDNA Arrays.

    Formaldehyde (FA) is a genotoxic chemical found in household, medicinal, and industrial products. Although the major source of human exposure is...

  14. A novel formaldehyde metabolic pathway plays an important role during formaldehyde metabolism and detoxification in tobacco leaves under liquid formaldehyde stress.

    PubMed

    Wang, Ru; Zeng, Zhidong; Liu, Ting; Liu, Ang; Zhao, Yan; Li, Kunzhi; Chen, Limei

    2016-08-01

    Tobacco and Arabidopsis are two model plants often used in botany research. Our previous study indicated that the formaldehyde (HCHO) uptake and assimilation capacities of tobacco leaves were weaker than those of Arabidopsis leaves. After treatment with a 2, 4 or 6 mM HCHO solution for 24 h, detached tobacco leaves absorbed approximately 40% of the HCHO from the treatment solution. (13)C-NMR analysis detected a novel HCHO metabolic pathway in 2 mM H(13)CHO-treated tobacco leaves. [4-(13)C]Asn, [3-(13)C]Gln and [U-(13)C]oxalic acid (OA) were produced from this pathway after H(13)COOH generation during H(13)CHO metabolism in tobacco leaves. Pretreatments of cyclosporin A (CSA) and dark almost completely inhibited the generation of [4-(13)C]Asn, [3-(13)C]Gln and [U-(13)C]OA from this pathway but did not suppressed the production of H(13)COOH in 2 mM H(13)CHO-treated tobacco leaves. The evidence suggests that this novel pathway has an important role during the metabolic detoxification of HCHO in tobacco leaves. The analysis of the chlorophyll and Rubisco contents indicated that CSA and dark pretreatments did not severely affect the survival of leaf cells but significantly inhibited the HCHO uptake by tobacco leaves. Based on the effects of CSA and dark pretreatments on HCHO uptake and metabolism, it is estimated that the contribution of this novel metabolic pathway to HCHO uptake is approximately 60%. The data obtained from the (13)C-NMR analysis revealed the mechanism underlying the weaker HCHO uptake and assimilation of tobacco leaves compared to Arabidopsis leaves. PMID:27116371

  15. Role of threonine dehydrogenase in Escherichia coli threonine degradation.

    PubMed Central

    Potter, R; Kapoor, V; Newman, E B

    1977-01-01

    Threonine was used as nitrogen source by Escherichia coli K-12 through a pathway beginning with the enzyme threonine dehydrogenase. The 2-amino-3-ketobutyrate formed was converted to glycine, and the glycine was converted to serine, which acted as the actual nitrogen donor. The enzyme formed under anaerobic conditions and known as threonine deaminase (biodegradative) is less widespread than threonine dehydrogenase and may be involved in energy metabolism rather than in threonine degradation per se. PMID:334738

  16. Role of ammonia in the activiation of methanol dehydrogenase/cytochrome C(L) enzyme

    NASA Astrophysics Data System (ADS)

    Kunjumon, Ancy

    Recent advancement in enzyme catalysis has opened ways to design efficient biocatalysts, bio-sensors and bio-fuel cells. An in-depth knowledge about the mechanism of the reaction taking place within the enzymes is of great importance to achieve these goals. In this dissertation, various computation methods are applied to investigate the mechanism behind enzyme catalysis in the presence of compounds called activators. Methanol dehydrogenase (MDH) is a well-known bio-catalyst that can oxidize excess of methanol from the environment to formaldehyde. The enzyme works well within the bacterial environment, but under in vitro, it loses activity. Ammonia is used as an activator to restore the activity of MDH. The Monte Carlo search using simulated annealing metaheuristic method is conducted to explore the binding of MDH with its natural electron acceptor Cytochrome cL in varying concentration of ammonia. The main aim behind this is to explore the interaction energy between the enzymes under the influence of its activator. The concentration of ammonia is varied from 0 to 5 ammonia molecules. Moving deeper into the active site of MDH, molecular mechanics and dynamics calculations were performed to investigate the position and effect of ammonia in the active site amino acids of MDH. The concentration of ammonia was varied from 0 to 55.39 mM. It was proposed that ammonia may form a complex conjugate with the cofactor of MDH (Pyrroloquinoline quinone) to assist in the oxidation of methanol. Two of the most debated methanol oxidation mechanisms, Addition-Elimination reaction and Hydride-Transfer mechanism, were used to investigate the role of ammonia in the oxidation of methanol. Density functional theory (DFT) was applied to explore the methanol oxidation mechanism in the presence of ammonia. Models of varying size that best represent the active site of MDH were tested for this purpose. The interaction energy obtained after the docking of MDH and Cytochrome cL (CL) indicate

  17. The putative role of ovary removal and progesterone when considering the effect of formaldehyde exposure on lung inflammation induced by ovalbumin

    PubMed Central

    Lino-dos-Santos-Franco, Adriana; Amemiya, Renata Midori; de Oliveira, Ana Paula Ligeiro; Damazo, Amílcar Sabino; Breithaupt-Faloppa, Ana Cristina; Vitoretti, Luana Beatriz; Acceturi, Beatriz Golegã; Tavares-de-Lima, Wothan

    2013-01-01

    OBJECTIVE: Formaldehyde exposure during the menstrual cycle is known to affect the course of allergic lung inflammation. Because our previous data demonstrated that formaldehyde combined with an ovariectomy reduced allergic lung inflammation, we investigated the putative role of ovary removal and progesterone treatment when considering the effect of formaldehyde on allergic lung inflammation. METHOD: Ovariectomized rats and their matched controls were exposed to formaldehyde (1%, 3 days, 90 min/day) or vehicle, and immediately after exposure, the rats were sensitized to ovalbumin by a subcutaneous route. After 1 week, the rats received a booster by the same route, and after an additional week, the rats were challenged with ovalbumin (1%) by an aerosol route. The leukocyte numbers, interleukin-10 (IL-10) release, myeloperoxidase activity, vascular permeability, ex vivo tracheal reactivity to methacholine and mast cell degranulation were determined 24 h later. RESULTS: Our results showed that previous exposure to formaldehyde in allergic rats decreased lung cell recruitment, tracheal reactivity, myeloperoxidase activity, vascular permeability and mast cell degranulation while increasing IL-10 levels. Ovariectomy only caused an additional reduction in tracheal reactivity without changing the other parameters studied. Progesterone treatment reversed the effects of formaldehyde exposure on ex vivo tracheal reactivity, cell influx into the lungs and mast cell degranulation. CONCLUSION: In conclusion, our study revealed that formaldehyde and ovariectomy downregulated allergic lung inflammation by IL-10 release and mast cell degranulation. Progesterone treatment increased eosinophil recruitment and mast cell degranulation, which in turn may be responsible for tracheal hyperreactivity and allergic lung inflammation. PMID:24473511

  18. Repair pathways independent of the Fanconi anemia nuclear core complex play a predominant role in mitigating formaldehyde-induced DNA damage

    SciTech Connect

    Noda, Taichi; Takahashi, Akihisa; Kondo, Natsuko; Mori, Eiichiro; Okamoto, Noritomo; Nakagawa, Yosuke; Ohnishi, Ken; Zdzienicka, Malgorzata Z.; Thompson, Larry H.; Helleday, Thomas; Asada, Hideo; and others

    2011-01-07

    The role of the Fanconi anemia (FA) repair pathway for DNA damage induced by formaldehyde was examined in the work described here. The following cell types were used: mouse embryonic fibroblast cell lines FANCA{sup -/-}, FANCC{sup -/-}, FANCA{sup -/-}C{sup -/-}, FANCD2{sup -/-} and their parental cells, the Chinese hamster cell lines FANCD1 mutant (mt), FANCGmt, their revertant cells, and the corresponding wild-type (wt) cells. Cell survival rates were determined with colony formation assays after formaldehyde treatment. DNA double strand breaks (DSBs) were detected with an immunocytochemical {gamma}H2AX-staining assay. Although the sensitivity of FANCA{sup -/-}, FANCC{sup -/-} and FANCA{sup -/-}C{sup -/-} cells to formaldehyde was comparable to that of proficient cells, FANCD1mt, FANCGmt and FANCD2{sup -/-} cells were more sensitive to formaldehyde than the corresponding proficient cells. It was found that homologous recombination (HR) repair was induced by formaldehyde. In addition, {gamma}H2AX foci in FANCD1mt cells persisted for longer times than in FANCD1wt cells. These findings suggest that formaldehyde-induced DSBs are repaired by HR through the FA repair pathway which is independent of the FA nuclear core complex. -- Research highlights: {yields} We examined to clarify the repair pathways of formaldehyde-induced DNA damage. Formaldehyde induces DNA double strand breaks (DSBs). {yields} DSBs are repaired through the Fanconi anemia (FA) repair pathway. {yields} This pathway is independent of the FA nuclear core complex. {yields} We also found that homologous recombination repair was induced by formaldehyde.

  19. Alcohol dehydrogenases in Acinetobacter sp. strain HO1-N: role in hexadecanse and hexadecanol metabolism

    SciTech Connect

    Singer, M.E.; Finnerty, W.R.

    1985-12-01

    Multiple alcohol dehydrogenases (ADH) were demonstrated in Acinetobacter sp. strain HO1-N. ADH-A and ADH-B were distinguished on the basis of electrophoretic mobility, pyridine nucleotide cofactor requirement, and substrate specificity. ADH-A is a soluble, NAD-linked, inducible ethanol dehydrogenase (EDH). An ethanol-negative mutant (Eth1) was isolated which contained 6.5% of wild-type EDH activity and was deficient in ADH-A. Eth1 exhibited normal growth on hexadecane and hexadecanol. A second ethanol-negative mutant (Eth3) was acetaldehyde dehydrogenase (ALDH) deficient, having 12.5% of wild-type ALDH activity. Eth3 had threefold-higher EDH activity than the wild-type strain. ALDH is a soluble, NAD-linked, ethanol-inducible enzyme. Eth3 exhibited normal growth on hexadecane, hexadecanol, and fatty aldehyde. ADH-B is soluble, constitutive, NADP-linked ADH which was active with medium-chain-length alcohols. Hexadecanol dehydrogenase (HDH), a soluble and membrane-bound, NAD-linked ADH, was induced 5- to 11-fold by growth on hexadecane or hexadecanol. HDH was distinct from ADH-A and ADH-B. NAD-linked HDH appears to possess a functional role in hexadecane and hexadecanol dissimilation.

  20. Dehydrogenase genes in the ectomycorrhizal fungus Tricholoma vaccinum: A role for Ald1 in mycorrhizal symbiosis.

    PubMed

    Henke, Catarina; Jung, Elke-Martina; Voit, Annekatrin; Kothe, Erika; Krause, Katrin

    2016-02-01

    Ectomycorrhizal symbiosis is important for forest ecosystem functioning with tree-fungal cooperation increasing performance and countering stress conditions. Aldehyde dehydrogenases (ALDHs) are key enzymes for detoxification and thus may play a role in stress response of the symbiotic association. With this focus, eight dehydrogenases, Ald1 through Ald7 and TyrA, of the ectomycorrhizal basidiomycete Tricholoma vaccinum were characterized and phylogenetically investigated. Functional analysis was performed through differential expression analysis by feeding different, environmentally important substances. A strong effect of indole-3-acetic acid (IAA) was identified, linking mycorrhiza formation and auxin signaling between the symbiosis partners. We investigated ald1 overexpressing strains for performance in mycorrhiza with the host tree spruce (Picea abies) and observed an increased width of the apoplast, accommodating the Hartig' net hyphae of the T. vaccinum over-expressing transformants. The results support a role for Ald1 in ectomycorrhiza formation and underline functional differentiation within fungal aldehyde dehydrogenases in the family 1 of ALDHs. PMID:26344933

  1. An update on the role of mitochondrial α-ketoglutarate dehydrogenase in oxidative stress

    PubMed Central

    Starkov, Anatoly A.

    2012-01-01

    The activity of mitochondrial alpha-ketoglutarate dehydrogenase complex (KGDHC) is severely reduced in human pathologies where oxidative stress is traditionally thought to play an important role, such as familial and sporadic forms of Alzheimer's disease and other age-related neurodegenerative diseases. This minireview is focused on substantial data that were accumulated over the last 2 decades to support the concept that KGDHC can be a primary mitochondrial target of oxidative stress and at the same time a key contributor to it by producing reactive oxygen species. This article is part of a Special Issue entitled ‘Mitochondrial function’. PMID:22820180

  2. A new role for α-ketoglutarate dehydrogenase complex: regulating metabolism through post-translational modification of other enzymes.

    PubMed

    McKenna, Mary C; Rae, Caroline D

    2015-07-01

    This Editorial highlights a study by Gibson et al. published in this issue of JNeurochem, in which the authors reveal a novel role for the α-ketoglutarate dehydrogenase complex (KGDHC) in post-translational modification of proteins. KGDHC may catalyze post-translational modification of itself as well as several other proteins by succinylation of lysine residues. The authors' report of an enzyme responsible for succinylation of key mitochondrial enzymes represents a major step toward our understanding of the complex functional metabolome. TCA, tricarboxylic acid; KG, α-ketoglutarate; KGDHC, α-ketoglutarate dehydrogenase complex; FUM, fumarase; MDH, malate dehydrogenase; ME, malic enzyme; GDH, glutamate dehydrogenase; AAT, aspartate aminotransferase; GS, glutamine synthetase; PAG, phosphate-activated glutaminase; SIRT3, silent information regulator 3; SIRT5, silent information regulator 5. PMID:26052752

  3. An original approach combining aircraft observations and 1D modelling to quantify the role of deep convection on formaldehyde in tropical UT

    NASA Astrophysics Data System (ADS)

    Borbon, A.; Ruiz, M.; Bechara, J.; Afif, C.; Huntrieser, H.; Mills, G.; Mari, C.; Reeves, C.; Schlager, H.

    2010-12-01

    Deep convection plays a key role in determining global atmospheric composition of the upper troposphere by the fast uplift of HOx radical and ozone precursors to the upper troposphere. Formaldehyde (HCHO) is one important gas precursor. It is the most abundant carbonyl compound originating from both primary processes and photooxidation of volatile organic compounds. Thus, determining its source strength to the upper troposphere is important for estimating ozone production. However processes governing its fate are multiple and complex including dynamics (entrainment and detrainment), multiphase chemistry and cloud microphysics. As a result, the flux of formaldehyde to the upper troposphere is still uncertain. The goal of this study is to examine the redistribution of formaldehyde in tropical mesoscale convective systems (MSC) and to estimate its sources and sinks during convective transport to the upper troposphere. The novelty here is to combine 1D modelling (Meso NH model) and formaldehyde aircraft observations. Observations were collected over West Africa during the monsoon period (July-August 2006) of the AMMA experiment. Four aircrafts (English BAe-146, French ATR-42 and Falcon-20 and German Falcon-20) were deployed over a large domain (long.: -8°E-5°W, lat. 4°N-20°N, alt.: 0 12 km) with formaldehyde measuring instruments on board. First, this presentation will point out the construction of a comprehensive and consistent data set of formaldehyde by ensuring data comparability thanks to aircraft intercomparison flights, multiple chemical tracer approach (CO, O3 and relative humidity) and a spatial gridding of the domain. Then formaldehyde spatial variability will be examined under background and convective conditions. Finally, the relative importance of transport (entrainment) and wet scavenging will be discussed from selected AMMA flights. For that purpose, the following equation system has been resolved [HCHO]transported to UT=[HCHO]measured - [HCHO

  4. The Role of Glutamine Oxoglutarate Aminotransferase and Glutamate Dehydrogenase in Nitrogen Metabolism in Mycobacterium bovis BCG

    PubMed Central

    Viljoen, Albertus J.; Kirsten, Catriona J.; Baker, Bienyameen; van Helden, Paul D.; Wiid, Ian J. F.

    2013-01-01

    Recent evidence suggests that the regulation of intracellular glutamate levels could play an important role in the ability of pathogenic slow-growing mycobacteria to grow in vivo. However, little is known about the in vitro requirement for the enzymes which catalyse glutamate production and degradation in the slow-growing mycobacteria, namely; glutamine oxoglutarate aminotransferase (GOGAT) and glutamate dehydrogenase (GDH), respectively. We report that allelic replacement of the Mycobacterium bovis BCG gltBD-operon encoding for the large (gltB) and small (gltD) subunits of GOGAT with a hygromycin resistance cassette resulted in glutamate auxotrophy and that deletion of the GDH encoding-gene (gdh) led to a marked growth deficiency in the presence of L-glutamate as a sole nitrogen source as well as reduction in growth when cultured in an excess of L-asparagine. PMID:24367660

  5. Fundamental molecular differences between alcohol dehydrogenase classes.

    PubMed Central

    Danielsson, O; Atrian, S; Luque, T; Hjelmqvist, L; Gonzàlez-Duarte, R; Jörnvall, H

    1994-01-01

    Two types of alcohol dehydrogenase in separate protein families are the "medium-chain" zinc enzymes (including the classical liver and yeast forms) and the "short-chain" enzymes (including the insect form). Although the medium-chain family has been characterized in prokaryotes and many eukaryotes (fungi, plants, cephalopods, and vertebrates), insects have seemed to possess only the short-chain enzyme. We have now also characterized a medium-chain alcohol dehydrogenase in Drosophila. The enzyme is identical to insect octanol dehydrogenase. It is a typical class III alcohol dehydrogenase, similar to the corresponding human form (70% residue identity), with mostly the same residues involved in substrate and coenzyme interactions. Changes that do occur are conservative, but Phe-51 is of functional interest in relation to decreased coenzyme binding and increased overall activity. Extra residues versus the human enzyme near position 250 affect the coenzyme-binding domain. Enzymatic properties are similar--i.e., very low activity toward ethanol (Km beyond measurement) and high selectivity for formaldehyde/glutathione (S-hydroxymethylglutathione; kcat/Km = 160,000 min-1.mM-1). Between the present class III and the ethanol-active class I enzymes, however, patterns of variability differ greatly, highlighting fundamentally separate molecular properties of these two alcohol dehydrogenases, with class III resembling enzymes in general and class I showing high variation. The gene coding for the Drosophila class III enzyme produces an mRNA of about 1.36 kb that is present at all developmental stages of the fly, compatible with the constitutive nature of the vertebrate enzyme. Taken together, the results bridge a previously apparent gap in the distribution of medium-chain alcohol dehydrogenases and establish a strictly conserved class III enzyme, consistent with an important role for this enzyme in cellular metabolism. Images PMID:8197167

  6. Role of cytosolic NADP+-dependent isocitrate dehydrogenase in ischemia-reperfusion injury in mouse kidney

    PubMed Central

    Kim, Jinu; Kim, Ki Young; Jang, Hee-Seong; Yoshida, Takumi; Tsuchiya, Ken; Nitta, Kosaku; Park, Jeen-Woo; Bonventre, Joseph V.; Park, Kwon Moo

    2009-01-01

    Cytosolic NADP+-dependent isocitrate dehydrogenase (IDPc) synthesizes reduced NADP (NADPH), which is an essential cofactor for the generation of reduced glutathione (GSH), the most abundant and important antioxidant in mammalian cells. We investigated the role of IDPc in kidney ischemia-reperfusion (I/R) in mice. The activity and expression of IDPc were highest in the cortex, modest in the outer medulla, and lowest in the inner medulla. NADPH levels were greatest in the cortex. IDPc expression in the S1 and S2 segments of proximal tubules was higher than in the S3 segment, which is much more susceptible to I/R. IDPc protein was also highly expressed in the mitochondrion-rich intercalated cells of the collecting duct. IDPc activity was 10- to 30-fold higher than the activity of glucose-6-phosphate dehydrogenase, another producer of cytosolic NADPH, in various kidney regions. This study identifies that IDPc may be the primary source of NADPH in the kidney. I/R significantly reduced IDPc expression and activity and NADPH production and increased the ratio of oxidized glutathione to total glutathione [GSSG/(GSH+GSSG)], resulting in kidney dysfunction, tubular cell damage, and lipid peroxidation. In LLC-PK1 cells, upregulation of IDPc by IDPc gene transfer protected the cells against hydrogen peroxide, enhancing NADPH production, inhibiting the increase of GSSG/(GSH+GSSG), and reducing lipid peroxidation. IDPc downregulation by small interference RNA treatment presented results contrasting with the upregulation. In conclusion, these results demonstrate that IDPc is expressed differentially along tubules in patterns that may contribute to differences in susceptibility to injury, is a major enzyme in cytosolic NADPH generation in kidney, and is downregulated with I/R. PMID:19106211

  7. Role of pyruvate dehydrogenase kinase isoenzyme 4 (PDHK4) in glucose homoeostasis during starvation

    PubMed Central

    Jeoung, Nam Ho; Wu, Pengfei; Joshi, Mandar A.; Jaskiewicz, Jerzy; Bock, Cheryl B.; Depaoli-Roach, Anna A.; Harris, Robert A.

    2006-01-01

    The PDC (pyruvate dehydrogenase complex) is strongly inhibited by phosphorylation during starvation to conserve substrates for gluconeogenesis. The role of PDHK4 (pyruvate dehydrogenase kinase isoenzyme 4) in regulation of PDC by this mechanism was investigated with PDHK4−/− mice (homozygous PDHK4 knockout mice). Starvation lowers blood glucose more in mice lacking PDHK4 than in wild-type mice. The activity state of PDC (percentage dephosphorylated and active) is greater in kidney, gastrocnemius muscle, diaphragm and heart but not in the liver of starved PDHK4−/− mice. Intermediates of the gluconeogenic pathway are lower in concentration in the liver of starved PDHK4−/− mice, consistent with a lower rate of gluconeogenesis due to a substrate supply limitation. The concentration of gluconeogenic substrates is lower in the blood of starved PDHK4−/− mice, consistent with reduced formation in peripheral tissues. Isolated diaphragms from starved PDHK4−/− mice accumulate less lactate and pyruvate because of a faster rate of pyruvate oxidation and a reduced rate of glycolysis. BCAAs (branched chain amino acids) are higher in the blood in starved PDHK4−/− mice, consistent with lower blood alanine levels and the importance of BCAAs as a source of amino groups for alanine formation. Non-esterified fatty acids are also elevated more in the blood of starved PDHK4−/− mice, consistent with lower rates of fatty acid oxidation due to increased rates of glucose and pyruvate oxidation due to greater PDC activity. Up-regulation of PDHK4 in tissues other than the liver is clearly important during starvation for regulation of PDC activity and glucose homoeostasis. PMID:16606348

  8. Report of the Federal Panel on Formaldehyde.

    PubMed Central

    1982-01-01

    The Federal Panel on Formaldehyde concluded that definitive experiments exist which demonstrate the mutagenicity and carcinogenicity of formaldehyde under laboratory conditions. Formaldehyde induces both gene mutations and chromosomal aberrations in a variety of test systems. Inhalation of formaldehyde causes cancer of the nose in rats. The concentrations of formaldehyde in inhaled air that caused nasal cancer in Fisher 344 rats are within the same order of magnitude as those to which humans may be exposed. The data presently available do not permit a direct assessment of the carcinogenicity of formaldehyde to man. Epidemiologic studies on exposed human populations are in progress and may further clarify the situation. Other experimental and human studies on toxic effects such as teratogenicity and reproductive disorders are as yet inadequate for a health risk assessment. The CIIT 24 month study on animal carcinogenicity has not yet been completely evaluated. Additional data are expected on the effects of prolonged exposure to lower doses of formaldehyde and on the possible carcinogenicity of formaldehyde in the mouse. The panel recommends that, for a comprehensive health risk assessment, further experiments be conducted on the effects of other modes of exposure (ingestion and skin penetration), the effects in humans, and on the pharmacokinetics of formaldehyde in man and animals and the possible role for formaldehyde in reproductive and chronic respiratory disorders. It is the conclusion of the panel that formaldehyde should be presumed to pose a carcinogenic risk to humans. PMID:6977445

  9. Mechanisms of Vascular Calcification: The Pivotal Role of Pyruvate Dehydrogenase Kinase 4

    PubMed Central

    2016-01-01

    Vascular calcification, abnormal mineralization of the vessel wall, is frequently associated with aging, atherosclerosis, diabetes mellitus, and chronic kidney disease. Vascular calcification is a key risk factor for many adverse clinical outcomes, including ischemic cardiac events and subsequent cardiovascular mortality. Vascular calcification was long considered to be a passive degenerative process, but it is now recognized as an active and highly regulated process similar to bone formation. However, despite numerous studies on the pathogenesis of vascular calcification, the mechanisms driving this process remain poorly understood. Pyruvate dehydrogenase kinases (PDKs) play an important role in the regulation of cellular metabolism and mitochondrial function. Recent studies show that PDK4 is an attractive therapeutic target for the treatment of various metabolic diseases. In this review, we summarize our current knowledge regarding the mechanisms of vascular calcification and describe the role of PDK4 in the osteogenic differentiation of vascular smooth muscle cells and development of vascular calcification. Further studies aimed at understanding the molecular mechanisms of vascular calcification will be critical for the development of novel therapeutic strategies. PMID:26996423

  10. Mechanisms of Vascular Calcification: The Pivotal Role of Pyruvate Dehydrogenase Kinase 4.

    PubMed

    Leem, Jaechan; Lee, In Kyu

    2016-03-01

    Vascular calcification, abnormal mineralization of the vessel wall, is frequently associated with aging, atherosclerosis, diabetes mellitus, and chronic kidney disease. Vascular calcification is a key risk factor for many adverse clinical outcomes, including ischemic cardiac events and subsequent cardiovascular mortality. Vascular calcification was long considered to be a passive degenerative process, but it is now recognized as an active and highly regulated process similar to bone formation. However, despite numerous studies on the pathogenesis of vascular calcification, the mechanisms driving this process remain poorly understood. Pyruvate dehydrogenase kinases (PDKs) play an important role in the regulation of cellular metabolism and mitochondrial function. Recent studies show that PDK4 is an attractive therapeutic target for the treatment of various metabolic diseases. In this review, we summarize our current knowledge regarding the mechanisms of vascular calcification and describe the role of PDK4 in the osteogenic differentiation of vascular smooth muscle cells and development of vascular calcification. Further studies aimed at understanding the molecular mechanisms of vascular calcification will be critical for the development of novel therapeutic strategies. PMID:26996423

  11. Fatty aldehyde dehydrogenases in Acinetobacter sp. strain HO1-N: role in hexadecane and hexadecanol metabolism

    SciTech Connect

    Singer, M.E.; Finnerty, W.R.

    1985-12-01

    The role of fatty aldehyde dehydrogenases (FALDHs) in hexadecane and hexadecanol metabolism was studied in Acinetobacter sp. strain HO1-N. Two distinct FALDHs were demonstrated in Acinetobacter sp. strain HO1-N: (i) a membrane-bound, NADP-dependent FALDH activity induced 5-, 15-, and 9 fold by growth on hexadecanol, dodecyl aldehyde, and hexadecane, respectively, and (ii) a constitutive, NAD-dependent, membrane-localized FALDH. Dodecyl aldehyde-negative mutants were isolated and grouped into two phenotypic classes based on growth: class 1 mutants were hexadecane and hexadecanol negative and class 2 mutants were hexadecane and hexadecanol positive. Specific activity of NADP-dependent FALDH in Ald21 (class 1 mutant) was 85% lower than that of wild-type FALDH, while the specific activity of Ald24 (class 2 mutant) was 55% greater than that of wild-type FALDH. Ald21R, a dodecyl aldehyde-positive revertant able to grow on hexadecane, hexadecanol, and dodecyl aldehyde, exhibited a 100% increase in the specific activity of the NADP-dependent FALDH. This study provides genetic and physiological evidence for the role of fatty aldehyde as an essential metabolic intermediate and NADP-dependent FALDH as a key enzyme in the dissimilation of hexadecane, hexadecanol, and dodecyl aldehyde in Acinetobacter sp. strain HO1-N.

  12. Purification and properties of an amine dehydrogenase from Pseudomonas AM1 and its role in growth on methylamine

    PubMed Central

    Eady, R. R.; Large, P. J.

    1968-01-01

    1. Whole cells of Pseudomonas AM1 grown on methylamine oxidize methylamine, formaldehyde and formate. Crude extracts oxidize methylamine only if supplemented with phenazine methosulphate. 2. By using a spectrophotometric assay, the methylamine-oxidizing enzyme has been purified 20-fold in 31% yield. 3. The enzyme is a dehydrogenase, unable to utilize oxygen, NAD, NADP, flavines or menadione as electron acceptors, but able to utilize phenazine methosulphate, ferricyanide, cytochrome c or brilliant cresyl blue. 4. The enzyme is non-specific, readily oxidizing aliphatic monoamines and diamines, histamine and ethanol-amine. Secondary and tertiary amines, quaternary ammonium salts and aromatic amines are not oxidized. 5. The pH optima for methylamine, n-pentylamine and putrescine are respectively 7·6, 8·0 and 8·5. 6. The Km value for methylamine is 5·2μm and that for phenazine methosulphate 56μm. 7. The enzyme will withstand heating for 15min. at 80° without loss of activity, but is inactivated at higher temperatures. It is not inactivated by any pH value between 2·6 and 10·6. 8. The dehydrogenase is inhibited by semicarbazide (Ki 3·35μm), isoniazid (Ki 1·17μm), cuprizone (Ki 0·49μm), p-chloromercuribenzoate (Ki 0·45mm) and quinacrine (Ki 12·1mm). 9. The enzyme is absent from succinate-grown cells, and, during adaptation from succinate to methylamine, activity appears before growth on methylamine begins. PMID:4388687

  13. Electrochemical conversion of carbon dioxide to methanol with the assistance of formate dehydrogenase and methanol dehydrogenase as biocatalysts

    SciTech Connect

    Kuwabata, Susumu; Tsuda, Ryo; Yoneyama, Hiroshi )

    1994-06-15

    Electrolysis at potentials between -0.7 and -0.9 V vs SCE of carbon dioxide-saturated phosphate buffer solutions (pH7) containing formate dehydrogenase (FDH) and either methyl viologen (MV[sup 2+]) or pyrroloquinolinequinone (PQQ) as an electron mediator yielded formate with current efficiencies as high as 90%. The enzyme was durable as long as the electrolysis was carried out in the dark. Electrolysis of phosphate buffer solutions containing sodium formate in the presence of methanol dehydrogenase (MDH) and MV[sup 2+] at -0.7 V vs SCE yielded formaldehyde if the concentration of the enzyme used was low, whereas both formaldehyde and methanol were produced for relatively high concentrations of the enzyme where the methanol production began to occur when the formaldehyde produced accumulated. The use of PQQ in place of MV[sup 2+] as the electron mediator exclusively produced methanol alone after some induction period in the electrolysis. On the basis of these results, successful attempts have been made to reduce carbon dioxide to methanol with cooperative assistance of FDH and MDH in the presence of PQQ as the electron mediator. The role of enzyme and mediator in these reduction processes is discussed in detail. 34 refs., 10 figs., 2 tabs.

  14. Role of aldehyde dehydrogenase in hypoxic vasodilator effects of nitrite in rats and humans

    PubMed Central

    Arif, Sayqa; Borgognone, Alessandra; Lin, Erica Lai-Sze; O'Sullivan, Aine G; Sharma, Vishal; Drury, Nigel E; Menon, Ashvini; Nightingale, Peter; Mascaro, Jorge; Bonser, Robert S; Horowitz, John D; Feelisch, Martin; Frenneaux, Michael P; Madhani, Melanie

    2015-01-01

    Background and Purpose Hypoxic conditions favour the reduction of nitrite to nitric oxide (NO) to elicit vasodilatation, but the mechanism(s) responsible for bioconversion remains ill defined. In the present study, we assess the role of aldehyde dehydrogenase 2 (ALDH2) in nitrite bioactivation under normoxia and hypoxia in the rat and human vasculature. Experimental Approach The role of ALDH2 in vascular responses to nitrite was studied using rat thoracic aorta and gluteal subcutaneous fat resistance vessels from patients with heart failure (HF; 16 patients) in vitro and by measurement of changes in forearm blood flow (FBF) during intra-arterial nitrite infusion (21 patients) in vivo. Specifically, we investigated the effects of (i) ALDH2 inhibition by cyanamide or propionaldehyde and the (ii) tolerance-independent inactivation of ALDH2 by glyceryl trinitrate (GTN) on the vasodilator activity of nitrite. In each setting, nitrite effects were measured via evaluation of the concentration–response relationship under normoxic and hypoxic conditions in the absence or presence of ALDH2 inhibitors. Key Results Both in rat aorta and human resistance vessels, dilatation to nitrite was diminished following ALDH2 inhibition, in particular under hypoxia. In humans there was a non-significant trend towards attenuation of nitrite-mediated increases in FBF. Conclusions and Implications In human and rat vascular tissue in vitro, hypoxic nitrite-mediated vasodilatation involves ALDH2. In patients with HF in vivo, the role of this enzyme in nitrite bioactivation is at the most, modest, suggesting the involvement of other more important mechanisms. PMID:25754766

  15. A putative role for inosine 5' monophosphate dehydrogenase (IMPDH) in Leishmania amazonensis programmed cell death.

    PubMed

    Pitaluga, A N; Moreira, M E C; Traub-Csekö, Y M

    2015-02-01

    Leishmania amazonensis undergoes apoptosis-like programmed cell death (PCD) under heat shock conditions. We identified a potential role for inosine 5' monophosphate dehydrogenase (IMPDH) in L. amazonensis PCD. Trypanosomatids do not have a "de novo" purine synthesis pathway, relying on the salvage pathway for survival. IMPDH, a key enzyme in the purine nucleotide pathway, is related to cell growth and apoptosis. Since guanine nucleotide depletion triggers cell cycle arrest and apoptosis in several organisms we analyzed the correlation between IMPDH and apoptosis-like death in L. amazonensis. The L. amazonensis IMPDH inhibition effect on PCD was evaluated through gene expression analysis, mitochondrial depolarization and detection of Annexin-V labeled parasites. We demonstrated a down-regulation of impdh expression under heat shock treatment, which mimics the natural mammalian host infection. Also, IMPDH inhibitors ribavirin and mycophenolic acid (MPA) prevented cell growth and generated an apoptosis-like phenotype in sub-populations of L. amazonensis promastigotes. Our results are in accordance with previous results showing that a subpopulation of parasites undergoes apoptosis-like cell death in the nutrient poor environment of the vector gut. Here, we suggest the involvement of purine metabolism in previously observed apoptosis-like cell death during Leishmania infection. PMID:25499513

  16. Role of lactate dehydrogenase in metmyoglobin reduction and color stability of different bovine muscles.

    PubMed

    Kim, Y H; Keeton, J T; Smith, S B; Berghman, L R; Savell, J W

    2009-11-01

    The role of lactate dehydrogenase (LDH) in metmyoglobin reducing activity (MRA) and color stability of different bovine muscles was studied in two consecutive experiments. In experiment 1, three different bovine muscles -M. longissimus lumborum (LL), M. semimembranosus (SM), and M. psoas major (PM) - were obtained (n=7, respectively), cut into steaks, PVC packaged, and then displayed for 7days at 1°C. The LL was the most red over display time and had more (P<0.05) LDH-B activity (catalyzing toward NADH generation), LDH1 isoform expression, NADH, and higher (P<0.05) MRA than the other two muscles studied. The PM had the least color stability and lowest MRA. In experiment 2, LL steaks (n=8) were cut in half, one side syringe-injected with oxamate, and the other injected with distilled water. Inclusion of oxamate decreased (P<0.05) LDH-B activity, NADH, and a* values after 10days display at 1°C. These results suggest that variation in color stability of physiologically different muscles is regulated by different replenishment rates of NADH via different LDH isozymes. PMID:20416707

  17. Role of carbon monoxide dehydrogenase in acetate synthesis by the acetogenic bacterium, Acetobacterium woodii.

    PubMed

    Shanmugasundaram, T; Ragsdale, S W; Wood, H G

    1988-07-01

    Carbon monoxide dehydrogenase (CODH) plays a key role in acetate synthesis by the acetogenic bacterium, Clostridium thermoaceticum. Acetobacterium woodii, like C. thermoaceticum contains high levels of CODH. In this work we show that crude extracts of A. woodii synthesize acetate from methyl tetrahydrofolate or methyl iodide, carbon monoxide and coenzyme A (CoA). The purified CODH from A. woodii catalyzes an exchange reaction between CO and the carbonyl group of acetyl-CoA even faster than the C. thermoaceticum enzyme, indicating the CODH of A. woodii, like that of C. thermoaceticum is an acetyl-CoA synthetase. Fluorescence and EPR studies further support this postulate by demonstrating that CODH binds CoA near the CO binding site involving a tryptophan residue. The UV absorption spectra and the amino acid compositions of A. woodii and C. thermoaceticum CODHs are very similar. Evidence is presented using purified enzymes from A. woodii that the synthesis of acetyl-CoA occurs by a pathway similar to that utilized by C. thermoaceticum. PMID:2855585

  18. The Role of Glutamine Synthetase and Glutamate Dehydrogenase in Cerebral Ammonia Homeostasis

    PubMed Central

    Cooper, Arthur J. L.

    2012-01-01

    In the brain, glutamine synthetase (GS), which is located predominantly in astrocytes, is largely responsible for the removal of both blood-derived and metabolically generated ammonia. Thus, studies with [13N]ammonia have shown that about 25% of blood-derived ammonia is removed in a single pass through the rat brain and that this ammonia is incorporated primarily into glutamine (amide) in astrocytes. Major pathways for cerebral ammonia generation include the glutaminase reaction and the glutamate dehydrogenase (GDH) reaction. The equilibrium position of the GDH-catalyzed reaction in vitro favors reductive amination of α-ketoglutarate at pH 7.4. Nevertheless, only a small amount of label derived from [13N]ammonia in rat brain is incorporated into glutamate and the α-amine of glutamine in vivo. Most likely the cerebral GDH reaction is drawn normally in the direction of glutamate oxidation (ammonia production) by rapid removal of ammonia as glutamine. Linkage of glutamate/α-ketoglutarate-utilizing aminotransferases with the GDH reaction channels excess amino acid nitrogen toward ammonia for glutamine synthesis. At high ammonia levels and/or when GS is inhibited the GDH reaction coupled with glutamate/α-ketoglutarate-linked aminotransferases may, however, promote the flow of ammonia nitrogen toward synthesis of amino acids. Preliminary evidence suggests an important role for the purine nucleotide cycle (PNC) as an additional source of ammonia in neurons (Net reaction: L-Aspartate + GTP + H2O → Fumarate + GDP + Pi + NH3) and in the beat cycle of ependyma cilia. The link of the PNC to aminotransferases and GDH/GS and its role in cerebral nitrogen metabolism under both normal and pathological (e.g. hyperammonemic encephalopathy) conditions should be a productive area for future research. PMID:22618691

  19. A role for the dehydrogenase DHRS7 (SDR34C1) in prostate cancer

    PubMed Central

    Seibert, Julia K; Quagliata, Luca; Quintavalle, Cristina; Hammond, Thomas G; Terracciano, Luigi; Odermatt, Alex

    2015-01-01

    Several microarray studies of prostate cancer (PCa) samples have suggested altered expression of the “orphan” enzyme short-chain dehydrogenase/reductase DHRS7 (retSDR4, SDR34C1). However, the role of DHRS7 in PCa is largely unknown and the impact of DHRS7 modulation on cancer cell properties has not yet been studied. Here, we investigated DHRS7 expression in normal human prostate and PCa tissue samples at different tumor grade using tissue microarray and immunovisualization. Moreover, we characterized the effects of siRNA-mediated DHRS7 knockdown on the properties of three distinct human prostate cell lines. We found that DHRS7 protein expression decreases alongside tumor grade, as judged by the Gleason level, in PCa tissue samples. The siRNA-mediated knockdown of DHRS7 expression in the human PCa cell lines LNCaP, BPH1, and PC3 significantly increased cell proliferation in LNCaP cells as well as cell migration in all of the investigated cell lines. Furthermore, cell adhesion was decreased upon DHRS7 knockdown in all three cell lines. To begin to understand the mechanisms underlying the effects of DHRS7 depletion, we performed a microarray study with samples from LNCaP cells treated with DHRS7-specific siRNA. Several genes involved in cell proliferation and adhesion pathways were found to be altered in DHRS7-depleted LNCaP cells. Additionally, genes of the BRCA1/2 pathway and the epithelial to mesenchymal transition regulator E-cadherin were altered following DHRS7 knockdown. Based on these results, further research is needed to evaluate the potential role of DHRS7 as a tumor suppressor and whether its loss-of-function promotes PCa progression and metastasis. PMID:26311046

  20. Role and structural characterization of plant aldehyde dehydrogenases from family 2 and family 7.

    PubMed

    Končitíková, Radka; Vigouroux, Armelle; Kopečná, Martina; Andree, Tomáš; Bartoš, Jan; Šebela, Marek; Moréra, Solange; Kopečný, David

    2015-05-15

    Aldehyde dehydrogenases (ALDHs) are responsible for oxidation of biogenic aldehyde intermediates as well as for cell detoxification of aldehydes generated during lipid peroxidation. So far, 13 ALDH families have been described in plants. In the present study, we provide a detailed biochemical characterization of plant ALDH2 and ALDH7 families by analysing maize and pea ALDH7 (ZmALDH7 and PsALDH7) and four maize cytosolic ALDH(cALDH)2 isoforms RF2C, RF2D, RF2E and RF2F [the first maize ALDH2 was discovered as a fertility restorer (RF2A)]. We report the crystal structures of ZmALDH7, RF2C and RF2F at high resolution. The ZmALDH7 structure shows that the three conserved residues Glu(120), Arg(300) and Thr(302) in the ALDH7 family are located in the substrate-binding site and are specific to this family. Our kinetic analysis demonstrates that α-aminoadipic semialdehyde, a lysine catabolism intermediate, is the preferred substrate for plant ALDH7. In contrast, aromatic aldehydes including benzaldehyde, anisaldehyde, cinnamaldehyde, coniferaldehyde and sinapaldehyde are the best substrates for cALDH2. In line with these results, the crystal structures of RF2C and RF2F reveal that their substrate-binding sites are similar and are formed by an aromatic cluster mainly composed of phenylalanine residues and several nonpolar residues. Gene expression studies indicate that the RF2C gene, which is strongly expressed in all organs, appears essential, suggesting that the crucial role of the enzyme would certainly be linked to the cell wall formation using aldehydes from phenylpropanoid pathway as substrates. Finally, plant ALDH7 may significantly contribute to osmoprotection because it oxidizes several aminoaldehydes leading to products known as osmolytes. PMID:25734422

  1. Role of Dihydrolipoamide Dehydrogenase in Regulation of Raffinose Transport in Streptococcus pneumoniae▿§

    PubMed Central

    Tyx, Robert E.; Roche-Hakansson, Hazeline; Hakansson, Anders P.

    2011-01-01

    Streptococcus pneumoniae strains lacking the enzyme dihydrolipoamide dehydrogenase (DLDH) show markedly reduced ability to grow on raffinose and stachyose as sole carbon sources. Import of these sugars occurs through the previously characterized raffinose ATP-binding cassette (ABC) transport system, encoded by the raf operon, that lacks the necessary ATP-binding protein. In this study, we identified the raffinose ATP-binding protein RafK and showed that it was directly involved in raffinose and stachyose import. RafK carries a C-terminal regulatory domain present in a subset of ATP-binding proteins that has been involved in both direct regulation of transporter activity (inducer exclusion) and transcription of transporter genes. Pneumococci lacking RafK showed a 50- to 80-fold reduction in expression of the raf operon genes aga (alpha-galactosidase) and rafEFG (raffinose substrate binding and permease genes), and both glucose and sucrose inhibited raffinose uptake through inducer exclusion. Like RafK, the presence of DLDH also activated the expression of raf operon genes, as DLDH-negative pneumococci showed a significantly decreased expression of aga and rafEFG, but DLDH did not regulate rafK or the putative regulatory genes rafR and rafS. DLDH also bound directly to RafK both in vitro and in vivo, indicating the possibility that DLDH regulates raffinose transport by a direct interaction with the regulatory domain of the transporter. Finally, although not as attenuated as DLDH-negative bacteria, pneumococci lacking RafK were significantly outcompeted by wild-type bacteria in colonization experiments of murine lung and nasopharynx, indicating a role for raffinose and stachyose transport in vivo. PMID:21602335

  2. High Resolution Formaldehyde Photochemistry

    NASA Astrophysics Data System (ADS)

    Ernest, C. T.; Bauer, D.; Hynes, A. J.

    2010-12-01

    Formaldehyde (HCHO) is the most abundant and most important organic carbonyl compound in the atmosphere. The sources of formaldehyde are the oxidation of methane, isoprene, acetone, and other volatile organic compounds (VOCs); fossil fuel combustion; and biomass burning. The dominant loss mechanism for formaldehyde is photolysis which occurs via two pathways: (R1) HCHO + hv → HCO + H (R2) HCHO + hv → H2 + CO The first pathway (R1) is referred to as the radical channel, while the second pathway (R2) is referred to as the molecular channel. The products of both pathways play a significant role in atmospheric chemistry. The CO that is produced in the molecular channel undergoes further oxidation to produce CO2. Under atmospheric conditions, the H atom and formyl radical that are produced in the radical channel undergo rapid reactions with O2 to produce the hydroperoxyl radical (HO2) via (R3) and (R4). (R3) HCO + O2 → HO2 + CO (R4) H + O2 → HO2 Thus, for every photon absorbed, the photolysis of formaldehyde can contribute one CO2 molecule to the global greenhouse budget or two HO2 radicals to the tropospheric HOx (OH + HO2) cycle. The HO2 radicals produced during formaldehyde photolysis have also been implicated in the formation of photochemical smog. The HO2 radicals act as radical chain carriers and convert NO to NO2, which ultimately results in the catalytic production of O3. Constraining the yield of HO2 produced via HCHO photolysis is essential for improving tropospheric chemistry models. In this study, both the absorption cross section and the quantum yield of the radical channel (R1) were measured at high resolution over the tropospherically relevant wavelength range 304-330 nm. For the cross section measurements a narrow linewidth Nd:YAG pumped dye laser was used with a multi-pass cell. Partial pressures of HCHO were kept below 0.3 torr. Simultaneous measurement of OH LIF in a flame allowed absolute calibration of the wavelength scale. Pressure

  3. Role of Alanine Dehydrogenase of Mycobacterium tuberculosis during Recovery from Hypoxic Nonreplicating Persistence

    PubMed Central

    Giffin, Michelle M.; Shi, Lanbo; Gennaro, Maria L.; Sohaskey, Charles D.

    2016-01-01

    Mycobacterium tuberculosis can maintain a nonreplicating persistent state in the host for decades, but must maintain the ability to efficiently reactivate and produce active disease to survive and spread in a population. Among the enzymes expressed during this dormancy is alanine dehydrogenase, which converts pyruvate to alanine, and glyoxylate to glycine concurrent with the oxidation of NADH to NAD. It is involved in the metabolic remodeling of M. tuberculosis through its possible interactions with both the glyoxylate and methylcitrate cycle. Both mRNA levels and enzymatic activities of isocitrate lyase, the first enzyme of the glyoxylate cycle, and alanine dehydrogenase increased during entry into nonreplicating persistence, while the gene and activity for the second enzyme of the glyoxylate cycle, malate synthase were not. This could suggest a shift in carbon flow away from the glyoxylate cycle and instead through alanine dehydrogenase. Expression of ald was also induced in vitro by other persistence-inducing stresses such as nitric oxide, and was expressed at high levels in vivo during the initial lung infection in mice. Enzyme activity was maintained during extended hypoxia even after transcription levels decreased. An ald knockout mutant of M. tuberculosis showed no reduction in anaerobic survival in vitro, but resulted in a significant lag in the resumption of growth after reoxygenation. During reactivation the ald mutant had an altered NADH/NAD ratio, and alanine dehydrogenase is proposed to maintain the optimal NADH/NAD ratio during anaerobiosis in preparation of eventual regrowth, and during the initial response during reoxygenation. PMID:27203084

  4. Role of Alanine Dehydrogenase of Mycobacterium tuberculosis during Recovery from Hypoxic Nonreplicating Persistence.

    PubMed

    Giffin, Michelle M; Shi, Lanbo; Gennaro, Maria L; Sohaskey, Charles D

    2016-01-01

    Mycobacterium tuberculosis can maintain a nonreplicating persistent state in the host for decades, but must maintain the ability to efficiently reactivate and produce active disease to survive and spread in a population. Among the enzymes expressed during this dormancy is alanine dehydrogenase, which converts pyruvate to alanine, and glyoxylate to glycine concurrent with the oxidation of NADH to NAD. It is involved in the metabolic remodeling of M. tuberculosis through its possible interactions with both the glyoxylate and methylcitrate cycle. Both mRNA levels and enzymatic activities of isocitrate lyase, the first enzyme of the glyoxylate cycle, and alanine dehydrogenase increased during entry into nonreplicating persistence, while the gene and activity for the second enzyme of the glyoxylate cycle, malate synthase were not. This could suggest a shift in carbon flow away from the glyoxylate cycle and instead through alanine dehydrogenase. Expression of ald was also induced in vitro by other persistence-inducing stresses such as nitric oxide, and was expressed at high levels in vivo during the initial lung infection in mice. Enzyme activity was maintained during extended hypoxia even after transcription levels decreased. An ald knockout mutant of M. tuberculosis showed no reduction in anaerobic survival in vitro, but resulted in a significant lag in the resumption of growth after reoxygenation. During reactivation the ald mutant had an altered NADH/NAD ratio, and alanine dehydrogenase is proposed to maintain the optimal NADH/NAD ratio during anaerobiosis in preparation of eventual regrowth, and during the initial response during reoxygenation. PMID:27203084

  5. NADPH recycling systems in oxidative stressed pea nodules: a key role for the NADP+ -dependent isocitrate dehydrogenase.

    PubMed

    Marino, Daniel; González, Esther M; Frendo, Pierre; Puppo, Alain; Arrese-Igor, Cesar

    2007-01-01

    The symbiosis between legumes and rhizobia is characterised by the formation of dinitrogen-fixing root nodules. In natural conditions, nitrogen fixation is strongly impaired by abiotic stresses which generate over-production of reactive oxygen species. Since one of the nodule main antioxidant systems is the ascorbate-glutathione cycle, NADPH recycling that is involved in glutathione reduction is of great relevance under stress conditions. NADPH is mainly produced by glucose 6-phosphate dehydrogenase (G6PDH; EC 1.1.1.49) and 6-phosphogluconate dehydrogenase (6PGDH; EC 1.1.1.44) from the oxidative pentose phosphate pathway, and also by NADP(+)-dependent isocitrate dehydrogenase (ICDH; EC 1.1.1.42). In this work, 10 microM paraquat (PQ) was applied to pea roots in order to determine the in vivo relationship between oxidative stress and the activity of the NADPH-generating enzymes in nodules. Whereas G6PDH and 6PGDH activities remained unchanged, a remarkable induction of ICDH gene expression and a dramatic increase of the ICDH activity was observed during the PQ treatment. These results support that ICDH has a key role in NADPH recycling under oxidative stress conditions in pea root nodules. PMID:16896792

  6. Engineering and Analysis of a Saccharomyces cerevisiae Strain That Uses Formaldehyde as an Auxiliary Substrate▿

    PubMed Central

    Baerends, Richard J. S.; de Hulster, Erik; Geertman, Jan-Maarten A.; Daran, Jean-Marc; van Maris, Antonius J. A.; Veenhuis, Marten; van der Klei, Ida J.; Pronk, Jack T.

    2008-01-01

    We demonstrated that formaldehyde can be efficiently coutilized by an engineered Saccharomyces cerevisiae strain that expresses Hansenula polymorpha genes encoding formaldehyde dehydrogenase (FLD1) and formate dehydrogenase (FMD), in contrast to wild-type strains. Initial chemostat experiments showed that the engineered strain coutilized formaldehyde with glucose, but these mixed-substrate cultures failed to reach steady-state conditions and did not exhibit an increased biomass yield on glucose. Subsequent transcriptome analyses of chemostat cultures of the engineered strain, grown on glucose-formaldehyde mixtures, indicated that the presence of formaldehyde in the feed caused biotin limitations. Further transcriptome analysis demonstrated that this biotin inactivation was prevented by using separate formaldehyde and vitamin feeds. Using this approach, steady-state glucose-limited chemostat cultures were obtained that coutilized glucose and formaldehyde. Coutilization of formaldehyde under these conditions resulted in an enhanced biomass yield of the glucose-limited cultures. The biomass yield was quantitatively consistent with the use of formaldehyde as an auxiliary substrate that generates NADH and subsequently, via oxidative phosphorylation, ATP. On an electron pair basis, the biomass yield increase observed with formaldehyde was larger than that observed previously for formate, which is tentatively explained by different modes of formate and formaldehyde transport in S. cerevisiae. PMID:18378663

  7. New formaldehyde base disinfectants.

    NASA Technical Reports Server (NTRS)

    Trujillo, R.; Lindell, K. F.

    1973-01-01

    Preparations of formaldehyde in various organic liquids - ethylene glycol, glycerol, and propylene glycol - serve as effective disinfectants towards microbial vegetative cells and spores. This disinfection is a temperature-dependent process and is manifest when these formaldehyde base disinfectants are dissolved in water. The irritating vapors associated with formaldehyde disinfection are not present in either of these new formaldehyde base disinfectants or in aqueous solutions of them.

  8. Dual and Opposing Roles of Xanthine Dehydrogenase in Defense-Associated Reactive Oxygen Species Metabolism in Arabidopsis.

    PubMed

    Ma, Xianfeng; Wang, Wenming; Bittner, Florian; Schmidt, Nadine; Berkey, Robert; Zhang, Lingli; King, Harlan; Zhang, Yi; Feng, Jiayue; Wen, Yinqiang; Tan, Liqiang; Li, Yue; Zhang, Qiong; Deng, Ziniu; Xiong, Xingyao; Xiao, Shunyuan

    2016-05-01

    While plants produce reactive oxygen species (ROS) for stress signaling and pathogen defense, they need to remove excessive ROS induced during stress responses in order to minimize oxidative damage. How can plants fine-tune this balance and meet such conflicting needs? Here, we show that XANTHINE DEHYDROGENASE1 (XDH1) in Arabidopsis thaliana appears to play spatially opposite roles to serve this purpose. Through a large-scale genetic screen, we identified three missense mutations in XDH1 that impair XDH1's enzymatic functions and consequently affect the powdery mildew resistance mediated by RESISTANCE TO POWDERY MILDEW8 (RPW8) in epidermal cells and formation of xanthine-enriched autofluorescent objects in mesophyll cells. Further analyses revealed that in leaf epidermal cells, XDH1 likely functions as an oxidase, along with the NADPH oxidases RbohD and RbohF, to generate superoxide, which is dismutated into H2O2 The resulting enrichment of H2O2 in the fungal haustorial complex within infected epidermal cells helps to constrain the haustorium, thereby contributing to RPW8-dependent and RPW8-independent powdery mildew resistance. By contrast, in leaf mesophyll cells, XDH1 carries out xanthine dehydrogenase activity to produce uric acid in local and systemic tissues to scavenge H2O2 from stressed chloroplasts, thereby protecting plants from stress-induced oxidative damage. Thus, XDH1 plays spatially specified dual and opposing roles in modulation of ROS metabolism during defense responses in Arabidopsis. PMID:27152019

  9. The Role of Pyruvate Dehydrogenase and Acetyl-Coenzyme A Synthetase in Fatty Acid Synthesis in Developing Arabidopsis Seeds1

    PubMed Central

    Ke, Jinshan; Behal, Robert H.; Back, Stephanie L.; Nikolau, Basil J.; Wurtele, Eve Syrkin; Oliver, David J.

    2000-01-01

    Acetyl-coenzyme A (acetyl-CoA) formed within the plastid is the precursor for the biosynthesis of fatty acids and, through them, a range of important biomolecules. The source of acetyl-CoA in the plastid is not known, but two enzymes are thought to be involved: acetyl-CoA synthetase and plastidic pyruvate dehydrogenase. To determine the importance of these two enzymes in synthesizing acetyl-CoA during lipid accumulation in developing Arabidopsis seeds, we isolated cDNA clones for acetyl-CoA synthetase and for the ptE1α- and ptE1β-subunits of plastidic pyruvate dehydrogenase. To our knowledge, this is the first reported acetyl-CoA synthetase sequence from a plant source. The Arabidopsis acetyl-CoA synthetase preprotein has a calculated mass of 76,678 D, an apparent plastid targeting sequence, and the mature protein is a monomer of 70 to 72 kD. During silique development, the spatial and temporal patterns of the ptE1β mRNA level are very similar to those of the mRNAs for the plastidic heteromeric acetyl-CoA carboxylase subunits. The pattern of ptE1β mRNA accumulation strongly correlates with the formation of lipid within the developing embryo. In contrast, the level of mRNA for acetyl-CoA synthetase does not correlate in time and space with lipid accumulation. The highest level of accumulation of the mRNA for acetyl-CoA synthetase during silique development is within the funiculus. These mRNA data suggest a predominant role for plastidic pyruvate dehydrogenase in acetyl-CoA formation during lipid synthesis in seeds. PMID:10859180

  10. Alcohol Dehydrogenase from Methylobacterium organophilum

    PubMed Central

    Wolf, H. J.; Hanson, R. S.

    1978-01-01

    The alcohol dehydrogenase from Methylobacterium organophilum, a facultative methane-oxidizing bacterium, has been purified to homogeneity as indicated by sodium dodecyl sulfate-gel electrophoresis. It has several properties in common with the alcohol dehydrogenases from other methylotrophic bacteria. The active enzyme is a dimeric protein, both subunits having molecular weights of about 62,000. The enzyme exhibits broad substrate specificity for primary alcohols and catalyzes the two-step oxidation of methanol to formate. The apparent Michaelis constants of the enzyme are 2.9 × 10−5 M for methanol and 8.2 × 10−5 M for formaldehyde. Activity of the purified enzyme is dependent on phenazine methosulfate. Certain characteristics of this enzyme distinguish it from the other alcohol dehydrogenases of other methylotrophic bacteria. Ammonia is not required for, but stimulates the activity of newly purified enzyme. An absolute dependence on ammonia develops after storage of the purified enzyme. Activity is not inhibited by phosphate. The fluorescence spectrum of the enzyme indicates that it and the cofactor associated with it may be chemically different from the alcohol dehydrogenases from other methylotrophic bacteria. The alcohol dehydrogenases of Hyphomicrobium WC-65, Pseudomonas methanica, Methylosinus trichosporium, and several facultative methylotrophs are serologically related to the enzyme purified in this study. The enzymes of Rhodopseudomonas acidophila and of organisms of the Methylococcus group did not cross-react with the antiserum prepared against the alcohol dehydrogenase of M. organophilum. Images PMID:80974

  11. Plant Formate Dehydrogenase

    SciTech Connect

    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.

  12. Azotobacter vinelandii Aldehyde Dehydrogenase Regulated by ς54: Role in Alcohol Catabolism and Encystment

    PubMed Central

    Gama-Castro, Socorro; Núñez, Cinthia; Segura, Daniel; Moreno, Soledad; Guzmán, Josefina; Espín, Guadalupe

    2001-01-01

    Encystment in Azotobacter vinelandii is induced by n-butanol or β-hydroxybutyrate (BHB). We identified a gene, encoding an aldehyde dehydrogenase, that was named aldA. An aldA mutation impaired bacterial growth on n-butanol, ethanol, or hexanol as the sole carbon source. Expression of aldA increased in cells shifted from sucrose to n-butanol and was shown to be dependent on the alternative ς54 factor. A mutation in rpoN encoding the ς54 factor also impaired growth on alcohols. Encystment on n-butanol, but not on BHB, was impaired in aldA or rpoN mutants, indicating that n-butanol is not an inducer of encystment by itself but must be catabolized in order to induce encystment. PMID:11591659

  13. Metabolic basis of ethylene glycol monobutyl ether (2-butoxyethanol) toxicity: role of alcohol and aldehyde dehydrogenases

    SciTech Connect

    Ghanayem, B.I.; Burka, L.T.; Matthews, H.B.

    1987-07-01

    2-Butoxyethanol (BE) is a massively produced glycol ether of which more than 230 million pounds was produced in the United States in 1983. It is extensively used in aerosols and cleaning agents intended for household use. This creates a high potential for human exposure during its manufacturing and use. A single exposure of rats to BE causes severe hemolytic anemia accompanied by secondary hemoglobinuria as well as liver and kidney damage. Butoxyacetic acid (BAA) was earlier identified as a urinary metabolite of BE. In addition, we have recently identified two additional urinary metabolites of BE, namely, BE-glucuronide and BE-sulfate conjugates. The current studies were undertaken to investigate the metabolic basis of BE-induced hematotoxicity in male F344 rats. Treatment of rats with pyrazole (alcohol dehydrogenase inhibitor) protected rats against BE-induced hematotoxicity and inhibited BE metabolism to BAA. Pyrazole inhibition of BE metabolism to BAA was accompanied by increased BE metabolism to BE-glucuronide and BE-sulfate as determined by quantitative high-performance liquid chromatography analysis of BE metabolites in urine. There was approximately a 10-fold decrease in the ratio of BAA to BE-glucuronide + BE-sulfate in the urine of rats treated with pyrazole + BE compared to rats treated with BE alone. Pretreatment of rats with cyanamide (aldehyde dehydrogenase inhibitor) also significantly protected rats against BE-induced hematotoxicity and modified BE metabolism in a manner similar to that caused by pyrazole. Administration of equimolar doses of BE, the metabolic intermediate butoxyacetaldehyde, or the ultimate metabolite BAA caused similar hematotoxic effects. Cyanamide also protected rats against butoxyacetaldehyde-induced hematotoxicity.

  14. On-line detection of atmospheric formaldehyde by a conductometric biosensor.

    PubMed

    Vianello, Fabio; Boscolo-Chio, Raffaella; Signorini, Stefano; Rigo, Adelio

    2007-01-15

    Atmospheric formaldehyde (CH(2)O) was detected under continuous flow conditions by an on-line system comprising of a wet scrubber for a continuous transfer of the pollutant to an aqueous solution, a micro-reactor containing immobilized formaldehyde dehydrogenase (FDH) and a conductometric transducer. By this system atmospheric formaldehyde concentrations in the range 0.05-2 ppm were detected with a sensitivity of 20 microS/ppm. In this concentration range the immobilized enzyme oxidized all the sampled formaldehyde molecules to formic acid, avoiding cumbersome calibration procedures. The operational stability of the biosensor was at least 3 months, working continuously 10 h/day at room temperature. PMID:16678399

  15. Microbial urea-formaldehyde degradation involves a new enzyme, methylenediurease.

    PubMed

    Jahns, T; Schepp, R; Siersdorfer, C; Kaltwasser, H

    1998-01-01

    The enzymic mechanism of metabolization of urea-formaldehyde condensation products (methyleneureas; MU) and the fate of the degradation products ammonium, urea and formaldehyde were studied in bacteria isolated from garden soil, which were able to use methyleneureas as the sole source of nitrogen for growth. An organism identified as Ochrobactrum anthropi completely degraded methylenediurea (MDU) and dimethylenetriurea (DMTU) to urea, ammonia, formaldehyde and carbon dioxide. An enzyme designated as methylenediurease (methylenediurea deiminase; MDUase) was responsible for the degradation of both MDU and DMTU as well as higher polymerized MU. Growth on MU as the nitrogen source specifically induced the synthesis of this enzyme, which seems to be located in the periplasm of the bacterium. Under these growth conditions, urease as well as NAD-specific formaldehyde and formiate dehydrogenase were expressed to high levels, efficiently using the products of MU degradation, and high-affinity transport systems for urea and ammonia were synthesized scavenging the environment for these products. PMID:10526991

  16. The role of cysteine in the alteration of bovine liver dihydrodiol dehydrogenase 3 activity.

    PubMed Central

    Nanjo, H; Adachi, H; Aketa, M; Mizoguchi, T; Nishihara, T; Terada, T

    1995-01-01

    Bovine liver NADP(+)-dependent dihydrodiol dehydrogenase (DD3) is extremely sensitive to SH reagents such as N-ethylmaleimide (NEM) and 5,5'-dithiobis(2-nitrobenzoic acid). NEM produced time- and concentration-dependent inactivation of DD3 in a pseudo-first-order reaction manner. This inactivation was prevented by NADP+, 3-acetylpyridine-adenine dinucleotide phosphate, 2',5'-ADP and 2'-AMP but not by substrates, NAD+, nicotinamide mononucleotide or 5'-ADP.DD3 was absorbed by an affinity column of thiopropyl-Sepharose 6B, but enzyme incubated with both NEM and NADP+ was not. Moreover, one [14C]NEM molecule was incorporated into a cysteine of DD3 in the presence, and two cysteines of DD3 in the absence, of NADP+. These results suggested that two cysteine residues were modified per enzyme molecule by NEM, one was protected by NADP+ and the other had no significant function for the enzyme activity. Two radiolabelled peptides (P1 and P2) produced by the digestion with lysyl endopeptidase of [14C]NEM-modified DD3 could be separated by reverse-phase HPLC. P1, which was radiolabelled by [14C]NEM only in the absence of NADP+, showed the following sequence; H2N-Tyr-Lys-Pro-Val-Xaa-Asn-Gln-Val-Glu- NEM.Cys-His-Pro-Tyr-Phe-Asn-Gln-Ser-Lys-COOH (Xaa indicates a possible cysteine residue). This sequence was very similar to that of rat liver 3 alpha-hydroxysteroid/dihydrodiol dehydrogenase (3 alpha-HSD/DD) (residues 184 to 201) and was also highly conserved in the aldo-keto reductase superfamily. The sequence of P2, which had radioactivity in both the absence and presence of NADP+, also contained an NEM-modified cysteine and was similar in sequence to the regions located in loop A of rat 3 alpha-HSD/DD. The present study suggests that P1, which may have a cysteine residue corresponding to Cys-193 of rat 3 alpha-HSD/DD, functions in the alteration of DD3 activity depending on the modulation of NADP(+)-binding ability through a thiol/disulphide exchange reaction similar to that of

  17. The Role of Δ1-Pyrroline-5-Carboxylate Dehydrogenase in Proline DegradationW⃞

    PubMed Central

    Deuschle, Karen; Funck, Dietmar; Forlani, Giuseppe; Stransky, Harald; Biehl, Alexander; Leister, Dario; van der Graaff, Eric; Kunze, Reinhard; Frommer, Wolf B.

    2004-01-01

    In response to stress, plants accumulate Pro, requiring degradation after release from adverse conditions. Δ1-Pyrroline-5-carboxylate dehydrogenase (P5CDH), the second enzyme for Pro degradation, is encoded by a single gene expressed ubiquitously. To study the physiological function of P5CDH, T-DNA insertion mutants in AtP5CDH were isolated and characterized. Although Pro degradation was undetectable in p5cdh mutants, neither increased Pro levels nor an altered growth phenotype were observed under normal conditions. Thus AtP5CDH is essential for Pro degradation but not required for vegetative plant growth. External Pro application caused programmed cell death, with callose deposition, reactive oxygen species production, and DNA laddering, involving a salicylic acid signal transduction pathway. p5cdh mutants were hypersensitive toward Pro and other molecules producing P5C, such as Arg and Orn. Pro levels were the same in the wild type and mutants, but P5C was detectable only in p5cdh mutants, indicating that P5C accumulation may be the cause for Pro hypersensitivity. Accordingly, overexpression of AtP5CDH resulted in decreased sensitivity to externally supplied Pro. Thus, Pro and P5C/Glu semialdehyde may serve as a link between stress responses and cell death. PMID:15548746

  18. Structure and function of Plasmodium falciparum malate dehydrogenase: role of critical amino acids in co-substrate binding pocket.

    PubMed

    Pradhan, Anupam; Tripathi, Abhai K; Desai, Prashant V; Mukherjee, Prasenjit K; Avery, Mitchell A; Walker, Larry A; Tekwani, Babu L

    2009-01-01

    The malaria parasite thrives on anaerobic fermentation of glucose for energy. Earlier studies from our laboratory have demonstrated that a cytosolic malate dehydrogenase (PfMDH) with striking similarity to lactate dehydrogenase (PfLDH) might complement PfLDH function in Plasmodium falciparum. The N-terminal glycine motif, which forms a characteristic Rossman dinucleotide-binding fold in the co-substrate binding pocket, differentiates PfMDH (GlyXGlyXXGly) from other eukaryotic and prokaryotic malate dehydrogenases (GlyXXGlyXXGly). The amino acids lining the co-substrate binding pocket are completely conserved in MDHs from different species of human, primate and rodent malaria parasites. Based on this knowledge and conserved domains among prokaryotic and eukaryotic MDH, the role of critical amino acids lining the co-substrate binding pocket was analyzed in catalytic functions of PfMDH using site-directed mutagenesis. Insertion of Ala at the 9th or 10th position, which converts the N-terminal GlyXGlyXXGly motif (characteristic of malarial MDH and LDH) to GlyXXGlyXXGly (as in bacterial and eukaryotic MDH), uncoupled regulation of the enzyme through substrate inhibition. The dinucleotide fold GlyXGlyXXGly motif seems not to be responsible for the distinct affinity of PfMDH to 3-acetylpyridine-adenine dinucleotide (APAD, a synthetic analog of NAD), since Ala9 and Ala10 insertion mutants still utilized APADH. The Gln11Met mutation, which converts the signature glycine motif in PfMDH to that of PfLDH, did not change the enzyme function. However, the Gln11Gly mutant showed approximately a 5-fold increase in catalytic activity, and higher susceptibility to inhibition with gossypol. Asn119 and His174 participate in binding of both co-substrate and substrate. The Asn119Gly mutant exhibited approximately a 3-fold decrease in catalytic efficiency, while mutation of His174 to Asn or Ala resulted in an inactive enzyme. These studies provide critical insights into the co

  19. Formaldehyde risk assessment

    EPA Science Inventory

    We would like to comment on the paper by Crump et al. (2008), ‘Sensitivity analysis of biologically motivated model for formaldehyde-induced respiratory cancer in humans’. We are authors of the formaldehyde cancer risk assessment described in Conolly et al. (2003, 2004) that is t...

  20. Optical Detection of Formaldehyde

    NASA Technical Reports Server (NTRS)

    Patty, Kira D.; Gregory, Don A.

    2008-01-01

    The potential for buildup .of formaldehyde in closed space environments poses a direct health hazard to personnel. The National Aeronautic Space Agency (NASA) has established a maximum permitted concentration of 0.04 ppm for 7 to 180 days for all space craft. Early detection is critical to ensure that formaldehyde levels do not accumulate. above these limits. New sensor technologies are needed to enable real time,in situ detection in a compact and reusable form factor. Addressing this need,research into the use of reactive fluorescent dyes which reversibly bind to formaldehyde (liquid or gas) has been conducted to support the development of a formaldehyde.sensor. In the presence of formaldehyde the dyes' characteristic fluorescence peaks shift providing the basis for an optical detection. Dye responses to formaldehyde exposure were characterized; demonstrating the optical detection of formaldehyde in under 10 seconds and down to concentrations of 0.5 ppm. To .incorporate the dye .in.an optical sensor device requires. a means of containing and manipulating the dye. Multiple form factors using two dissimilar sbstrates were considered to determine a suitable configuration. A prototype sensor was demonstrated and considerations for a field able sensor were presented. This research provides a necessary first step toward the development of a compact, reusable; real time optical formaldehyde sensor suitable for use in the U.S. space program,

  1. Melamine-formaldehyde aerogels

    DOEpatents

    Pekala, R.W.

    1992-01-14

    Organic aerogels that are transparent and essentially colorless are prepared from the aqueous, sol-gel polymerization of melamine with formaldehyde. The melamine-formaldehyde (MF) aerogels have low densities, high surface areas, continuous porosity, ultrafine cell/pore sizes, and optical clarity. 3 figs.

  2. Formaldehyde in Our Environment.

    ERIC Educational Resources Information Center

    Ojanlatva, Ansa; Weeks, Charlie A.

    During the energy crisis of the early 1970s, there was a drive to conserve energy in every segment of society. Citizens were encouraged to insulate their homes and tighten them up to avoid loss of energy. One of the products to emerge from this crisis was urea formaldehyde foam insulation. (Urea formaldehyde is a well-known agent for preserving…

  3. Melamine-formaldehyde aerogels

    DOEpatents

    Pekala, Richard Walter

    1992-01-01

    Organic aerogels that are transparent and essentially colorless are prepa from the aqueous, sol-gel polymerization of melamine with formaldehyde. The melamine-formaldehyde (MF) aerogels have low densities, high surface areas, continuous porsity, ultrafine cell/pore sizes, and optical clarity.

  4. Photobiomodulation Therapy Decreases Oxidative Stress in the Lung Tissue after Formaldehyde Exposure: Role of Oxidant/Antioxidant Enzymes.

    PubMed

    Silva Macedo, Rodrigo; Peres Leal, Mayara; Braga, Tarcio Teodoro; Barioni, Éric Diego; de Oliveira Duro, Stephanie; Ratto Tempestini Horliana, Anna Carolina; Câmara, Niels Olsen Saraiva; Marcourakis, Tânia; Farsky, Sandra Helena Poliselli; Lino-Dos-Santos-Franco, Adriana

    2016-01-01

    Formaldehyde is ubiquitous pollutant that induces oxidative stress in the lung. Several lung diseases have been associated with oxidative stress and their control is necessary. Photobiomodulation therapy (PBMT) has been highlighted as a promissory treatment, but its mechanisms need to be better investigated. Our objective was to evaluate the effects of PBMT on the oxidative stress generated by FA exposure. Male Wistar rats were submitted to FA exposure of 1% or vehicle (3 days) and treated or not with PBMT (1 and 5 h after each FA exposure). Rats treated only with laser were used as control. Twenty-four hours after the last FA exposure, we analyzed the effects of PBMT on the generation of nitrites and hydrogen peroxide, oxidative burst, glutathione reductase, peroxidase, S-transferase enzyme activities, the gene expression of nitric oxide, cyclooxygenase, superoxide dismutase, the catalase enzyme, and heme oxygenase-1. PBMT reduced the generation of nitrites and hydrogen peroxide and increased oxidative burst in the lung cells. A decreased level of oxidant enzymes was observed which were concomitantly related to an increased level of antioxidants. This study provides new information about the antioxidant mechanisms of PBMT in the lung and might constitute an important tool for lung disease treatment. PMID:27293324

  5. Photobiomodulation Therapy Decreases Oxidative Stress in the Lung Tissue after Formaldehyde Exposure: Role of Oxidant/Antioxidant Enzymes

    PubMed Central

    Braga, Tarcio Teodoro; Barioni, Éric Diego; de Oliveira Duro, Stephanie; Ratto Tempestini Horliana, Anna Carolina; Câmara, Niels Olsen Saraiva; Marcourakis, Tânia; Farsky, Sandra Helena Poliselli; Lino-dos-Santos-Franco, Adriana

    2016-01-01

    Formaldehyde is ubiquitous pollutant that induces oxidative stress in the lung. Several lung diseases have been associated with oxidative stress and their control is necessary. Photobiomodulation therapy (PBMT) has been highlighted as a promissory treatment, but its mechanisms need to be better investigated. Our objective was to evaluate the effects of PBMT on the oxidative stress generated by FA exposure. Male Wistar rats were submitted to FA exposure of 1% or vehicle (3 days) and treated or not with PBMT (1 and 5 h after each FA exposure). Rats treated only with laser were used as control. Twenty-four hours after the last FA exposure, we analyzed the effects of PBMT on the generation of nitrites and hydrogen peroxide, oxidative burst, glutathione reductase, peroxidase, S-transferase enzyme activities, the gene expression of nitric oxide, cyclooxygenase, superoxide dismutase, the catalase enzyme, and heme oxygenase-1. PBMT reduced the generation of nitrites and hydrogen peroxide and increased oxidative burst in the lung cells. A decreased level of oxidant enzymes was observed which were concomitantly related to an increased level of antioxidants. This study provides new information about the antioxidant mechanisms of PBMT in the lung and might constitute an important tool for lung disease treatment. PMID:27293324

  6. The formaldehyde dilemma.

    PubMed

    Salthammer, Tunga

    2015-06-01

    The IARC's 2004 classification of formaldehyde as a human carcinogen has led to intensive discussion on scientific and regulatory levels. In June 2014, the European Union followed and classified formaldehyde as a cause of cancer. This automatically triggers consequences in terms of emission minimization and the health-related assessment of building and consumer products. On the other hand, authorities are demanding and authorizing technologies and products which can release significant quantities of formaldehyde into the atmosphere. In the outdoor environment, this particularly applies to combusting fuels. The formation of formaldehyde through photochemical smog has also been a recognized problem for years. Indoors there are various processes which can contribute to increased formaldehyde concentrations. Overall, legislation faces a dilemma: primary sources are often over-regulated while a lack of consideration of secondary sources negates the regulations' effects. PMID:25772784

  7. Role of Quinones in Electron Transfer of PQQ–Glucose Dehydrogenase Anodes—Mediation or Orientation Effect

    SciTech Connect

    Babanova, Sofia; Matanovic, Ivana; Chavez, Madelaine Seow; Atanassov, Plamen

    2015-06-24

    In this study, the influence of two quinones (1,2- and 1,4-benzoquinone) on the operation and mechanism of electron transfer in PQQ-dependent glucose dehydrogenase (PQQ–sGDH) anodes has been determined. Benzoquinones were experimentally explored as mediators present in the electrolyte. The electrochemical performance of the PQQ–sGDH anodes with and without the mediators was examined and for the first time molecular docking simulations were used to gain a fundamental understanding to explain the role of the mediator molecules in the design and operation of the enzymatic electrodes. It was proposed that the higher performance of the PQQ–sGDH anodes in the presence of 1,2- and 1,4-benzoquinones introduced in the solution is due to the shorter distance between these molecules and PQQ in the enzymatic molecule. It was also hypothesized that when 1,4-benzoquinone is adsorbed on a carbon support, it would play the dual role of a mediator and an orienting agent. At the same time, when 1,2-benzoquinone and ubiquinone are adsorbed on the electrode surface, the enzyme would transfer the electrons directly to the support, and these molecules would primarily play the role of an orienting agent.

  8. Role of Quinones in Electron Transfer of PQQ-Glucose Dehydrogenase Anodes—Mediation or Orientation Effect.

    PubMed

    Babanova, Sofia; Matanovic, Ivana; Chavez, Madelaine Seow; Atanassov, Plamen

    2015-06-24

    In this study, the influence of two quinones (1,2- and 1,4-benzoquinone) on the operation and mechanism of electron transfer in PQQ-dependent glucose dehydrogenase (PQQ-sGDH) anodes has been determined. Benzoquinones were experimentally explored as mediators present in the electrolyte. The electrochemical performance of the PQQ-sGDH anodes with and without the mediators was examined and for the first time molecular docking simulations were used to gain a fundamental understanding to explain the role of the mediator molecules in the design and operation of the enzymatic electrodes. It was proposed that the higher performance of the PQQ-sGDH anodes in the presence of 1,2- and 1,4-benzoquinones introduced in the solution is due to the shorter distance between these molecules and PQQ in the enzymatic molecule. It was also hypothesized that when 1,4-benzoquinone is adsorbed on a carbon support, it would play the dual role of a mediator and an orienting agent. At the same time, when 1,2-benzoquinone and ubiquinone are adsorbed on the electrode surface, the enzyme would transfer the electrons directly to the support, and these molecules would primarily play the role of an orienting agent. PMID:26046816

  9. Role of disulfiram in the in vitro inhibition of rat liver mitochondrial aldehyde dehydrogenase.

    PubMed

    Shen, M L; Lipsky, J J; Naylor, S

    2000-10-01

    The alcohol aversion therapy drug disulfiram has been shown to inhibit hepatic aldehyde dehydrogenase (ALDH), one of the key enzymes involved in ethanol metabolism. It is believed by some that disulfiram could be one of the active inhibitors in vivo. However, the actual interaction between disulfiram and ALDH remains ambiguous. We report here that when disulfiram inhibited recombinant rat liver mitochondrial ALDH (rlmALDH) in vitro, no significant molecular mass increase was detected during the first 30 min as determined by on-line HPLC-electrospray ionization mass spectrometry (LC-MS). This indicated that the inhibition in vitro was not caused directly by covalent adduct formation on the enzyme. We subsequently subjected both control and disulfiram-inhibited rlmALDH to Glu-C proteolytic digestion. LC-MS analysis of the Glu-C digestion of disulfiram-inhibited enzyme revealed that one peptide of M(r) = 4821, which contained the putative active site of the enzyme, exhibited a mass decrease of 2 amu as compared with the same peptide found in the Glu-C digestion of the control (M(r) = 4823). We believe that the loss of 2 amu indicated that inhibition of rlmALDH in vitro was due to formation of an intramolecular disulfide bond between two of the three adjacent cysteines in the active site, possibly via a very rapid and unstable mixed disulfide interchange reaction. Further confirmation of the intramolecular disulfide bond formation came from the fact that by adding dithiothreitol (DTT) we were able to recover partial enzyme activity. In addition, the peptide of M(r) = 4821 observed in the Glu-C digestion of the disulfiram-treated ALDH reverted to M(r) = 4823 after treatment with DTT, which indicated that the disulfide bond was reduced. We, thereby, conclude that disulfiram inhibited rlmALDH by forming an intramolecular disulfide, possibly via a fast intermolecular disulfiram interchange reaction. PMID:10974203

  10. New insights in dihydropyrimidine dehydrogenase deficiency: a pivotal role for beta-aminoisobutyric acid?

    PubMed Central

    Van Kuilenburg, André B P; Stroomer, Alida E M; Van Lenthe, Henk; Abeling, Nico G G M; Van Gennip, Albert H

    2004-01-01

    DPD (dihydropyrimidine dehydrogenase) constitutes the first step of the pyrimidine degradation pathway, in which the pyrimidine bases uracil and thymine are catabolized to beta-alanine and the R-enantiomer of beta-AIB (beta-aminoisobutyric acid) respectively. The S-enantiomer of beta-AIB is predominantly derived from the catabolism of valine. It has been suggested that an altered homoeostasis of beta-alanine underlies some of the clinical abnormalities encountered in patients with a DPD deficiency. In the present study, we demonstrated that only a slightly decreased concentration of beta-alanine was present in the urine and plasma, whereas normal levels of beta-alanine were present in the cerebrospinal fluid of patients with a DPD deficiency. Therefore the metabolism of beta-alanine-containing peptides, such as carnosine, may be an important factor involved in the homoeostasis of beta-alanine in patients with DPD deficiency. The mean concentration of beta-AIB was approx. 2-3-fold lower in cerebrospinal fluid and urine of patients with a DPD deficiency, when compared with controls. In contrast, strongly decreased levels (10-fold) of beta-AIB were present in the plasma of DPD patients. Our results demonstrate that, under pathological conditions, the catabolism of valine can result in the production of significant amounts of beta-AIB. Furthermore, the observation that the R-enantiomer of beta-AIB is abundantly present in the urine of DPD patients suggests that significant cross-over exists between the thymine and valine catabolic pathways. PMID:14705962

  11. Acyloin production from aldehydes in the perfused rat heart: the potential role of pyruvate dehydrogenase.

    PubMed Central

    Montgomery, J A; Jetté, M; Huot, S; Des Rosiers, C

    1993-01-01

    Aldehydes represent an important class of cytotoxic products derived from free radical-induced lipid peroxidation which may contribute to reperfusion injury following myocardial infarct. Metabolism of aldehydes in the heart has not been well characterized aside from conjugation of unsaturated aldehydes with glutathione. However, aliphatic aldehydes like hexanal do not form stable glutathione conjugates. We have recently demonstrated in vitro that pig heart pyruvate dehydrogenase catalyses a reaction between pyruvate and saturated aldehydes to produce acyloins (3-hydroxyalkan-2-ones). In the present study, rat hearts were perfused with various aldehydes and pyruvate. Acyloins were generated from saturated aldehydes (butanal, hexanal or nonanal), but not from 2-hexanal (an unsaturated aldehyde) or malondialdehyde. Hearts perfused with 2 mM pyruvate and 10-100 microM hexanal rapidly took up hexanal in a dose-related manner (140-850 nmol/min), and released 3-hydroxyoctan-2-one (0.7-30 nmol/min), 2,3-octanediol (0-12 nmol/min) and hexanol (10-200 nmol/min). Small quantities of hexanoic acid (about 10 nmol/min) were also released. The rate of release of acyloin metabolites rose with increased concentration of hexanal, whereas hexanol release attained a plateau when hexanal infusion concentrations rose above 50 microM. Up to 50% of hexanal uptake could be accounted for by metabolite release. Less than 0.5% of hexanal uptake was found to be bound to acid-precipitable macromolecules. When hearts perfused with 50 microM hexanal and 2 mM pyruvate were subjected to a 15 min ischaemic period, the rates of release of 2,3-octanediol, 3-hydroxyoctan-2-one, hexanol and hexanoate during the reperfusion period were not significantly different from those in the pre-ischaemic period. Our results indicate that saturated aldehydes can be metabolically converted by the heart into stable diffusible compounds. PMID:8379929

  12. New insights in dihydropyrimidine dehydrogenase deficiency: a pivotal role for beta-aminoisobutyric acid?

    PubMed

    Van Kuilenburg, André B P; Stroomer, Alida E M; Van Lenthe, Henk; Abeling, Nico G G M; Van Gennip, Albert H

    2004-04-01

    DPD (dihydropyrimidine dehydrogenase) constitutes the first step of the pyrimidine degradation pathway, in which the pyrimidine bases uracil and thymine are catabolized to beta-alanine and the R-enantiomer of beta-AIB (beta-aminoisobutyric acid) respectively. The S-enantiomer of beta-AIB is predominantly derived from the catabolism of valine. It has been suggested that an altered homoeostasis of beta-alanine underlies some of the clinical abnormalities encountered in patients with a DPD deficiency. In the present study, we demonstrated that only a slightly decreased concentration of beta-alanine was present in the urine and plasma, whereas normal levels of beta-alanine were present in the cerebrospinal fluid of patients with a DPD deficiency. Therefore the metabolism of beta-alanine-containing peptides, such as carnosine, may be an important factor involved in the homoeostasis of beta-alanine in patients with DPD deficiency. The mean concentration of beta-AIB was approx. 2-3-fold lower in cerebrospinal fluid and urine of patients with a DPD deficiency, when compared with controls. In contrast, strongly decreased levels (10-fold) of beta-AIB were present in the plasma of DPD patients. Our results demonstrate that, under pathological conditions, the catabolism of valine can result in the production of significant amounts of beta-AIB. Furthermore, the observation that the R-enantiomer of beta-AIB is abundantly present in the urine of DPD patients suggests that significant cross-over exists between the thymine and valine catabolic pathways. PMID:14705962

  13. Structure and Function of Plasmodium falciparum malate dehydrogenase: Role of Critical Amino Acids in C-substrate Binding Procket

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Malaria parasite thrives on anaerobic fermentation of glucose for energy. Earlier studies from our lab have demonstrated that a cytosolic malate dehydrogenase (PfMDH) with striking similarity to lactate dehydrogenase (PfLDH) might complement PfLDH function in Plasmodium falciparum. The N-terminal g...

  14. On the role of Brønsted catalysis in Pseudomonas fluorescens mannitol 2-dehydrogenase.

    PubMed

    Klimacek, Mario; Kavanagh, Kathryn L; Wilson, David K; Nidetzky, Bernd

    2003-10-01

    X-ray structure of the Pseudomonas fluorescens mannitol 2-dehydrogenase ternary complex with NAD+ and D-mannitol suggests that Lys-295 provides catalytic base assistance to secondary alcohol group oxidation. We have replaced Lys-295 by site-directed mutagenesis with alanine or methionine and evaluated the catalytic significance of side-chain substitution by kinetic analysis of restoration of activity with external amines, and from pH and solvent isotope effects on the reaction catalysed by K295A (Lys-295-->Ala mutant). K295A and K295M (Lys-295-->Met mutants) show 3x10(4)- and 2x10(6)-fold lower turnover numbers respectively for D-mannitol oxidation (kcatO) at pH 10.0 than the wild-type. The second-order rate constant for non-covalent rescue of activity (kB) by free methylamine base is 31 M(-1) x s(-1) for K295A, but only 0.021 M(-1) x s(-1) for K295M. A Brønsted relationship of log kB (corrected for molecular size effects) and pKa of the external amine is linear (slope beta=0.66+/-0.16; r2=0.99) for K295A-catalysed D-mannitol oxidation at pH 10.0. The kcatO values of K295A in H2O and 2H2O are linearly dependent on [OL-] in the pL range 7.5-10.5 (where L is 1H or 2H). The solvent isotope effect on kcatO is 0.69. The time course of D-fructose reduction by K295A at pH 8.2 displays a pre-steady-state burst of NADH consumption. These data support a mechanism in which the epsilon -NH2 group of Lys-295 participates in an obligatory pH-dependent, pre-catalytic equilibrium which may control alcohol/alkoxide equilibration of enzyme-bound D-mannitol and activates the C2 atom for subsequent catalytic oxidation by NAD+. PMID:12826012

  15. Microfabricated Formaldehyde Gas Sensors

    PubMed Central

    Flueckiger, Jonas; Ko, Frank K.; Cheung, Karen C.

    2009-01-01

    Formaldehyde is a volatile organic compound that is widely used in textiles, paper, wood composites, and household materials. Formaldehyde will continuously outgas from manufactured wood products such as furniture, with adverse health effects resulting from prolonged low-level exposure. New, microfabricated sensors for formaldehyde have been developed to meet the need for portable, low-power gas detection. This paper reviews recent work including silicon microhotplates for metal oxide-based detection, enzyme-based electrochemical sensors, and nanowire-based sensors. This paper also investigates the promise of polymer-based sensors for low-temperature, low-power operation. PMID:22291561

  16. Major Role of NAD-Dependent Lactate Dehydrogenases in Aerobic Lactate Utilization in Lactobacillus plantarum during Early Stationary Phase

    PubMed Central

    Goffin, Philippe; Lorquet, Frédérique; Kleerebezem, Michiel; Hols, Pascal

    2004-01-01

    NAD-independent lactate dehydrogenases are commonly thought to be responsible for lactate utilization during the stationary phase of aerobic growth in Lactobacillus plantarum. To substantiate this view, we constructed single and double knockout mutants for the corresponding genes, loxD and loxL. Lactate-to-acetate conversion was not impaired in these strains, while it was completely blocked in mutants deficient in NAD-dependent lactate dehydrogenase activities, encoded by the ldhD and ldhL genes. We conclude that NAD-dependent but not NAD-independent lactate dehydrogenases are involved in this process. PMID:15375150

  17. Aldehyde Dehydrogenase-2 (ALDH2) Ameliorates Chronic Alcohol Ingestion-Induced Hepatic Steatosis and Inflammation: Role of Autophagy

    PubMed Central

    Guo, Rui; Xu, Xihui; Babcock, Sara A.; Zhang, Yingmei; Ren, Jun

    2014-01-01

    Background & Aims Mitochondrial aldehyde dehydrogenase (ALDH2) plays a critical role in the detoxification of the ethanol metabolite acetaldehyde. This study was designed to examine the impact of global ALDH2 overexpression on alcohol-induced hepatic steatosis. Methods Wild-type friendly virus B (FVB) and ALDH2 transgenic mice were placed on a 4% alcohol or control diet for 12 weeks. Serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), bilirubin and cholesterol, hepatic triglyceride, steatosis, fat metabolism-related proteins, pro-inflammatory cytokines, glutathione (GSH), oxidized glutathione (GSSG), autophagy and autophagy signaling were examined. The role of autophagy was evaluated in ADH1-transfected human hepatocellular liver carcinoma cells (VA-13) treated with or without autophagy inducer rapamycin and lysosomal inhibitors. Results Chronic alcohol intake led to elevated AST, ALT, bilirubin, AST/ALT ratio, cholesterol, hepatic triglycerides, hepatic fat deposition as evidenced by H&E and oil Red O staining, associated with disturbed fat metabolism-related proteins (fatty acid synthase, SCD1), upregulated interleukin-6, TNF-α, cyclooxygenase, oxidative stress, and loss of autophagy, the effects of which were attenuated or ablated by ALDH2 transgene. Moreover, ethanol (100 mM) and acetaldehyde (100, 500 μM) increased levels of IL-6 and IFN-γ, and suppressed autophagy in VA-13 cells, the effects of which were markedly alleviated by rapamycin. In addition, lysosomal inhibitors mimicked ethanol-induced p62 accumulation with little additive effect with ethanol. Ethanol significantly suppressed LC3 conversion in the presence of lysosomal inhibitors. Conclusions In summary, our results revealed that ALDH2 plays a beneficial role in ameliorating chronic alcohol intake-induced hepatic steatosis and inflammation through regulation of autophagy. PMID:25457208

  18. Putative role of the malate valve enzyme NADP-malate dehydrogenase in H2O2 signalling in Arabidopsis.

    PubMed

    Heyno, Eiri; Innocenti, Gilles; Lemaire, Stéphane D; Issakidis-Bourguet, Emmanuelle; Krieger-Liszkay, Anja

    2014-04-19

    In photosynthetic organisms, sudden changes in light intensity perturb the photosynthetic electron flow and lead to an increased production of reactive oxygen species. At the same time, thioredoxins can sense the redox state of the chloroplast. According to our hypothesis, thioredoxins and related thiol reactive molecules downregulate the activity of H2O2-detoxifying enzymes, and thereby allow a transient oxidative burst that triggers the expression of H2O2 responsive genes. It has been shown recently that upon light stress, catalase activity was reversibly inhibited in Chlamydomonas reinhardtii in correlation with a transient increase in the level of H2O2. Here, it is shown that Arabidopsis thaliana mutants lacking the NADP-malate dehydrogenase have lost the reversible inactivation of catalase activity and the increase in H2O2 levels when exposed to high light. The mutants were slightly affected in growth and accumulated higher levels of NADPH in the chloroplast than the wild-type. We propose that the malate valve plays an essential role in the regulation of catalase activity and the accumulation of a H2O2 signal by transmitting the redox state of the chloroplast to other cell compartments. PMID:24591715

  19. Resolving the Role of Plant Glutamate Dehydrogenase. I. in vivo Real Time Nuclear Magnetic Resonance Spectroscopy Experiments

    PubMed Central

    Labboun, Soraya; Tercé-Laforgue, Thérèse; Roscher, Albrecht; Bedu, Magali; Restivo, Francesco M.; Velanis, Christos N.; Skopelitis, Damianos S.; Moshou, Panagiotis N.; Roubelakis-Angelakis, Kalliopi A.; Suzuki, Akira; Hirel, Bertrand

    2009-01-01

    In higher plants the glutamate dehydrogenase (GDH) enzyme catalyzes the reversible amination of 2-oxoglutarate to form glutamate, using ammonium as a substrate. For a better understanding of the physiological function of GDH either in ammonium assimilation or in the supply of 2-oxoglutarate, we used transgenic tobacco (Nicotiana tabacum L.) plants overexpressing the two genes encoding the enzyme. An in vivo real time 15N-nuclear magnetic resonance (NMR) spectroscopy approach allowed the demonstration that, when the two GDH genes were overexpressed individually or simultaneously, the transgenic plant leaves did not synthesize glutamate in the presence of ammonium when glutamine synthetase (GS) was inhibited. In contrast we confirmed that the primary function of GDH is to deaminate Glu. When the two GDH unlabeled substrates ammonium and Glu were provided simultaneously with either [15N]Glu or 15NH4+ respectively, we found that the ammonium released from the deamination of Glu was reassimilated by the enzyme GS, suggesting the occurrence of a futile cycle recycling both ammonium and Glu. Taken together, these results strongly suggest that the GDH enzyme, in conjunction with NADH-GOGAT, contributes to the control of leaf Glu homeostasis, an amino acid that plays a central signaling and metabolic role at the interface of the carbon and nitrogen assimilatory pathways. Thus, in vivo NMR spectroscopy appears to be an attractive technique to follow the flux of metabolites in both normal and genetically modified plants. PMID:19690000

  20. Physiological Regulation of Isocitrate Dehydrogenase and the Role of 2-Oxoglutarate in Prochlorococcus sp. Strain PCC 9511

    PubMed Central

    Diez, Jesús; Gómez-Baena, Guadalupe; Rangel-Zúñiga, Oriol Alberto; García-Fernández, José Manuel

    2014-01-01

    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. PMID:25061751

  1. Essentiality of Succinate Dehydrogenase in Mycobacterium smegmatis and Its Role in the Generation of the Membrane Potential Under Hypoxia

    PubMed Central

    Pecsi, Ildiko; Hards, Kiel; Ekanayaka, Nandula; Berney, Michael; Hartman, Travis; Jacobs, William R.

    2014-01-01

    ABSTRACT Succinate:quinone oxidoreductase (Sdh) is a membrane-bound complex that couples the oxidation of succinate to fumarate in the cytoplasm to the reduction of quinone to quinol in the membrane. Mycobacterial species harbor genes for two putative sdh operons, but the individual roles of these two operons are unknown. In this communication, we show that Mycobacterium smegmatis mc2155 expresses two succinate dehydrogenases designated Sdh1 and Sdh2. Sdh1 is encoded by a five-gene operon (MSMEG_0416-MSMEG_0420), and Sdh2 is encoded by a four-gene operon (MSMEG_1672-MSMEG_1669). These two operons are differentially expressed in response to carbon limitation, hypoxia, and fumarate, as monitored by sdh promoter-lacZ fusions. While deletion of the sdh1 operon did not yield any growth phenotypes on succinate or other nonfermentable carbon sources, the sdh2 operon could be deleted only in a merodiploid background, demonstrating that Sdh2 is essential for growth. Sdh activity and succinate-dependent proton pumping were detected in cells grown aerobically, as well as under hypoxia. Fumarate reductase activity was absent under these conditions, indicating that neither Sdh1 nor Sdh2 could catalyze the reverse reaction. Sdh activity was inhibited by the Sdh inhibitor 3-nitroproprionate (3NP), and treatment with 3NP dissipated the membrane potential of wild-type or Δsdh1 mutant cells under hypoxia but not that of cells grown aerobically. These data imply that Sdh2 is the generator of the membrane potential under hypoxia, an essential role for the cell. PMID:25118234

  2. Cloning and characterization of sulfite dehydrogenase, two c-type cytochromes, and a flavoprotein of Paracoccus denitrificans GB17: essential role of sulfite dehydrogenase in lithotrophic sulfur oxidation.

    PubMed

    Wodara, C; Bardischewsky, F; Friedrich, C G

    1997-08-01

    A 13-kb genomic region of Paracoccus dentrificans GB17 is involved in lithotrophic thiosulfate oxidation. Adjacent to the previously reported soxB gene (C. Wodara, S. Kostka, M. Egert, D. P. Kelly, and C. G. Friedrich, J. Bacteriol. 176:6188-6191, 1994), 3.7 kb were sequenced. Sequence analysis revealed four additional open reading frames, soxCDEF. soxC coded for a 430-amino-acid polypeptide with an Mr of 47,339 that included a putative signal peptide of 40 amino acids (Mr of 3,599) with a RR motif present in periplasmic proteins with complex redox centers. The mature soxC gene product exhibited high amino acid sequence similarity to the eukaryotic molybdoenzyme sulfite oxidase and to nitrate reductase. We constructed a mutant, GBsoxC delta, carrying an in-frame deletion in soxC which covered a region possibly coding for the molybdenum cofactor binding domain. GBsoxC delta was unable to grow lithoautotrophically with thiosulfate but grew well with nitrate as a nitrogen source or as an electron acceptor. Whole cells and cell extracts of mutant GBsoxC delta contained 10% of the thiosulfate-oxidizing activity of the wild type. Only a marginal rate of sulfite-dependent cytochrome c reduction was observed from cell extracts of mutant GBsoxC delta. These results demonstrated that sulfite dehydrogenase was essential for growth with thiosulfate of P. dentrificans GB17. soxD coded for a periplasmic diheme c-type cytochrome of 384 amino acids (Mr of 39,983) containing a putative signal peptide with an Mr of 2,363. soxE coded for a periplasmic monoheme c-type cytochrome of 236 amino acids (Mr of 25,926) containing a putative signal peptide with an Mr of 1,833. SoxD and SoxE were highly identical to c-type cytochromes of P. denitrificans and other organisms. soxF revealed an incomplete open reading frame coding for a peptide of 247 amino acids with a putative signal peptide (Mr of 2,629). The deduced amino acid sequence of soxF was 47% identical and 70% similar to the sequence

  3. High blood alcohol levels in women. The role of decreased gastric alcohol dehydrogenase activity and first-pass metabolism.

    PubMed

    Frezza, M; di Padova, C; Pozzato, G; Terpin, M; Baraona, E; Lieber, C S

    1990-01-11

    After consuming comparable amounts of ethanol, women have higher blood ethanol concentrations than men, even with allowance for differences in size, and are more susceptible to alcoholic liver disease. Recently, we documented significant "first-pass metabolism" of ethanol due to its oxidation by gastric tissue. We report a study of the possible contribution of this metabolism to the sex-related difference in blood alcohol concentrations in 20 men and 23 women. Six in each group were alcoholics. The first-pass metabolism was determined on the basis of the difference in areas under the curves of blood alcohol concentrations after intravenous and oral administration of ethanol (0.3 g per kilogram of body weight). Alcohol dehydrogenase activity was also measured in endoscopic gastric biopsies. In nonalcoholic subjects, the first-pass metabolism and gastric alcohol dehydrogenase activity of the women were 23 and 59 percent, respectively, of those in the men, and there was a significant correlation (rs = 0.659) between first-pass metabolism and gastric mucosal alcohol dehydrogenase activity. In the alcoholic men, the first-pass metabolism and gastric alcohol dehydrogenase activity were about half those in the nonalcoholic men; in the alcoholic women, the gastric mucosal alcohol dehydrogenase activity was even lower than in the alcoholic men, and first-pass metabolism was virtually abolished. We conclude that the increased bioavailability of ethanol resulting from decreased gastric oxidation of ethanol may contribute to the enhanced vulnerability of women to acute and chronic complications of alcoholism. PMID:2248624

  4. Role of Δ1-Pyrroline-5-Carboxylate Dehydrogenase Supports Mitochondrial Metabolism and Host-Cell Invasion of Trypanosoma cruzi*

    PubMed Central

    Mantilla, Brian S.; Paes, Lisvane S.; Pral, Elizabeth M. F.; Martil, Daiana E.; Thiemann, Otavio H.; Fernández-Silva, Patricio; Bastos, Erick L.; Silber, Ariel M.

    2015-01-01

    Proline is crucial for energizing critical events throughout the life cycle of Trypanosoma cruzi, the etiological agent of Chagas disease. The proline breakdown pathway consists of two oxidation steps, both of which produce reducing equivalents as follows: the conversion of proline to Δ1-pyrroline-5-carboxylate (P5C), and the subsequent conversion of P5C to glutamate. We have identified and characterized the Δ1-pyrroline-5-carboxylate dehydrogenase from T. cruzi (TcP5CDH) and report here on how this enzyme contributes to a central metabolic pathway in this parasite. Size-exclusion chromatography, two-dimensional gel electrophoresis, and small angle x-ray scattering analysis of TcP5CDH revealed an oligomeric state composed of two subunits of six protomers. TcP5CDH was found to complement a yeast strain deficient in PUT2 activity, confirming the enzyme's functional role; and the biochemical parameters (Km, kcat, and kcat/Km) of the recombinant TcP5CDH were determined, exhibiting values comparable with those from T. cruzi lysates. In addition, TcP5CDH exhibited mitochondrial staining during the main stages of the T. cruzi life cycle. mRNA and enzymatic activity levels indicated the up-regulation (6-fold change) of TcP5CDH during the infective stages of the parasite. The participation of P5C as an energy source was also demonstrated. Overall, we propose that this enzymatic step is crucial for the viability of both replicative and infective forms of T. cruzi. PMID:25623067

  5. Role of Δ1-pyrroline-5-carboxylate dehydrogenase supports mitochondrial metabolism and host-cell invasion of Trypanosoma cruzi.

    PubMed

    Mantilla, Brian S; Paes, Lisvane S; Pral, Elizabeth M F; Martil, Daiana E; Thiemann, Otavio H; Fernández-Silva, Patricio; Bastos, Erick L; Silber, Ariel M

    2015-03-20

    Proline is crucial for energizing critical events throughout the life cycle of Trypanosoma cruzi, the etiological agent of Chagas disease. The proline breakdown pathway consists of two oxidation steps, both of which produce reducing equivalents as follows: the conversion of proline to Δ(1)-pyrroline-5-carboxylate (P5C), and the subsequent conversion of P5C to glutamate. We have identified and characterized the Δ(1)-pyrroline-5-carboxylate dehydrogenase from T. cruzi (TcP5CDH) and report here on how this enzyme contributes to a central metabolic pathway in this parasite. Size-exclusion chromatography, two-dimensional gel electrophoresis, and small angle x-ray scattering analysis of TcP5CDH revealed an oligomeric state composed of two subunits of six protomers. TcP5CDH was found to complement a yeast strain deficient in PUT2 activity, confirming the enzyme's functional role; and the biochemical parameters (Km, kcat, and kcat/Km) of the recombinant TcP5CDH were determined, exhibiting values comparable with those from T. cruzi lysates. In addition, TcP5CDH exhibited mitochondrial staining during the main stages of the T. cruzi life cycle. mRNA and enzymatic activity levels indicated the up-regulation (6-fold change) of TcP5CDH during the infective stages of the parasite. The participation of P5C as an energy source was also demonstrated. Overall, we propose that this enzymatic step is crucial for the viability of both replicative and infective forms of T. cruzi. PMID:25623067

  6. The role of glycerol-3-phosphate dehydrogenase 1 in the progression of fatty liver after acute ethanol administration in mice

    SciTech Connect

    Sato, Tomoki; Morita, Akihito; Mori, Nobuko; Miura, Shinji

    2014-02-21

    Highlights: • Ethanol administration increased GPD1 mRNA expression. • Ethanol administration increased glucose incorporation into TG glycerol moieties. • No increase in hepatic TG levels was observed in ethanol-injected GPD1 null mice. • We propose that GPD1 is required for ethanol-induced TG accumulation in the liver. - Abstract: Acute ethanol consumption leads to the accumulation of triglycerides (TGs) in hepatocytes. The increase in lipogenesis and reduction of fatty acid oxidation are implicated as the mechanisms underlying ethanol-induced hepatic TG accumulation. Although glycerol-3-phosphate (Gro3P), formed by glycerol kinase (GYK) or glycerol-3-phosphate dehydrogenase 1 (GPD1), is also required for TG synthesis, the roles of GYK and GPD1 have been the subject of some debate. In this study, we examine (1) the expression of genes involved in Gro3P production in the liver of C57BL/6J mice in the context of hepatic TG accumulation after acute ethanol intake, and (2) the role of GPD1 in the progression of ethanol-induced fatty liver using GPD1 null mice. As a result, in C57BL/6J mice, ethanol-induced hepatic TG accumulation began within 2 h and was 1.7-fold greater than that observed in the control group after 6 h. The up-regulation of GPD1 began 2 h after administering ethanol, and significantly increased 6 h later with the concomitant escalation in the glycolytic gene expression. The incorporation of {sup 14}C-labelled glucose into TG glycerol moieties increased during the same period. On the other hand, in GPD1 null mice carrying normal GYK activity, no significant increase in hepatic TG level was observed after acute ethanol intake. In conclusion, GPD1 and glycolytic gene expression is up-regulated by ethanol, and GPD1-mediated incorporation of glucose into TG glycerol moieties together with increased lipogenesis, is suggested to play an important role in ethanol-induced hepatic TG accumulation.

  7. Development of melamine-formaldehyde resin microcapsules with low formaldehyde emission suited for seed treatment.

    PubMed

    Yuan, Huizhu; Li, Guangxing; Yang, Lijuan; Yan, Xiaojing; Yang, Daibin

    2015-04-01

    To reduce the application frequency and improve the efficacy of insecticides, melamine-formaldehyde (MF) resin microcapsules suited for seed treatment containing a mixture of fipronil and chlorpyrifos were prepared by in situ polymerization. A formaldehyde/melamine molar ratio of 4:1 yielded microcapsules with the smallest size and the most narrow size distribution. The level of unreacted formaldehyde in the microcapsule suspension increased proportionally with the F/M molar ratio. When the MF resin microcapsule suspension was used as a seed treatment to coat peanut seeds, the unreacted formaldehyde did not significantly inhibit the seedling emergence, but the ongoing release of formaldehyde generated from the degradation of MF resins played an important role in inhibiting emergence. Melamine was shown to be an effective formaldehyde scavenger that mitigated this inhibition when it was incorporated within the microcapsule wall. Field experiments showed that MF-resin-encapsulated mixtures of fipronil and chlorpyrifos have much greater efficacies against white grubs than the conventional formulation. PMID:25734968

  8. BLM protein mitigates formaldehyde-induced genomic instability

    PubMed Central

    Kumari, Anuradha; Owen, Nichole; Juarez, Eleonora; McCullough, Amanda K.

    2015-01-01

    Formaldehyde is a reactive aldehyde that has been classified as a class I human carcinogen by the International Agency for Cancer Research. There are growing concerns over the possible adverse health effects related to the occupational and environmental human exposures to formaldehyde. Although formaldehyde-induced DNA and protein adducts have been identified, the genomic instability mechanisms and the cellular tolerance pathways associated with formaldehyde exposure are not fully characterized. This study specifically examines the role of a genome stability protein, Bloom (BLM) in limiting formaldehyde-induced cellular and genetic abnormalities. Here, we show that in the absence of BLM protein, formaldehyde-treated cells exhibited increased cellular sensitivity, an immediate cell cycle arrest, and an accumulation of chromosome radial structures. In addition, live-cell imaging experiments demonstrated that formaldehyde-treated cells are dependent on BLM for timely segregation of daughter cells. Both wild-type and BLM-deficient formaldehyde-treated cells showed an accumulation of 53BP1 and γH2AX foci indicative of DNA double-strand breaks (DSBs); however, relative to wild-type cells, the BLM-deficient cells exhibited delayed repair. In response to formaldehyde exposure, we observed co-localization of 53BP1 and BLM foci at the DSB repair site, where ATM-dependent accumulation of formaldehyde-induced BLM foci occurred after the recruitment of 53BP1. Together, these findings highlight the significance of functional interactions among ATM, 53BP1, and BLM proteins as responders associated with the repair and tolerance mechanisms induced by formaldehyde. PMID:25770783

  9. Delineation of the roles of amino acids involved in the catalytic functions of Leuconostoc mesenteroides glucose 6-phosphate dehydrogenase.

    PubMed

    Vought, V; Ciccone, T; Davino, M H; Fairbairn, L; Lin, Y; Cosgrove, M S; Adams, M J; Levy, H R

    2000-12-12

    The roles of particular amino acids in substrate and coenzyme binding and catalysis of glucose-6-phosphate dehydrogenase of Leuconostoc mesenteroides have been investigated by site-directed mutagenesis, kinetic analysis, and determination of binding constants. The enzyme from this species has functional dual NADP(+)/NAD(+) specificity. Previous investigations in our laboratories determined the three-dimensional structure. Kinetic studies showed an ordered mechanism for the NADP-linked reaction while the NAD-linked reaction is random. His-240 was identified as the catalytic base, and Arg-46 was identified as important for NADP(+) but not NAD(+) binding. Mutations have been selected on the basis of the three-dimensional structure. Kinetic studies of 14 mutant enzymes are reported and kinetic mechanisms are reported for 5 mutant enzymes. Fourteen substrate or coenzyme dissociation constants have been measured for 11 mutant enzymes. Roles of particular residues are inferred from k(cat), K(m), k(cat)/K(m), K(d), and changes in kinetic mechanism. Results for enzymes K182R, K182Q, K343R, and K343Q establish Lys-182 and Lys-343 as important in binding substrate both to free enzyme and during catalysis. Studies of mutant enzymes Y415F and Y179F showed no significant contribution for Tyr-415 to substrate binding and only a small contribution for Tyr-179. Changes in kinetics for T14A, Q47E, and R46A enzymes implicate these residues, to differing extents, in coenzyme binding and discrimination between NADP(+) and NAD(+). By the same measure, Lys-343 is also involved in defining coenzyme specificity. Decrease in k(cat) and k(cat)/K(m) for the D374Q mutant enzyme defines the way Asp-374, unique to L. mesenteroides G6PD, modulates stabilization of the enzyme during catalysis by its interaction with Lys-182. The greatly reduced k(cat) values of enzymes P149V and P149G indicate the importance of the cis conformation of Pro-149 in accessing the correct transition state. PMID

  10. [Allergic contact dermatitis caused by formaldehyde and formaldehyde releasers].

    PubMed

    Latorre, N; Silvestre, J F; Monteagudo, A F

    2011-03-01

    Formaldehyde is a colorless gas with a pungent odor that is widely used as a preservative in toiletries and cosmetics and in products for household and industrial use. Both formaldehyde itself and substances that can release it are a common cause of allergic contact dermatitis. This condition often becomes chronic, given that these allergens are found nearly everywhere and it is difficult for patients to avoid them completely. This article reviews the sources of exposure to formaldehyde and formaldehyde releasers and the clinical manifestations of allergen exposure. We also review current debates and recent developments and propose guidelines for the diagnosis and treatment of patients with formaldehyde contact dermatitis. PMID:21338980

  11. A Role for Lactate Dehydrogenases in the Survival of Neisseria gonorrhoeae in Human Polymorphonuclear Leukocytes and Cervical Epithelial Cells

    PubMed Central

    Atack, John M.; Ibranovic, Ines; Ong, Cheryl-Lynn Y.; Djoko, Karrera Y.; Chen, Nathan H.; vanden Hoven, Rachel; Jennings, Michael P.; Edwards, Jennifer L.; McEwan, Alastair G.

    2014-01-01

    Lactate is an abundant metabolite, produced by host tissues and commensal organisms, and it represents an important potential carbon source for bacterial pathogens. In the case of Neisseria spp., the importance of the lactate permease in colonization of the host has been demonstrated, but there have been few studies of lactate metabolism in pathogenic Neisseria in the postgenomic era. We describe herein the characterization of genome-annotated, respiratory, and substrate-level lactate dehydrogenases (LDHs) from the obligate human pathogen Neisseria gonorrhoeae. Biochemical assays using N. gonorrhoeae 1291 wild type and isogenic mutant strains showed that cytoplasmic LdhA (NAD+-dependent D-lactate dehydrogenase) and the membrane-bound respiratory enzymes, LdhD (D-lactate dehydrogenase) and LldD (L-lactate dehydrogenase) are correctly annotated. Mutants lacking LdhA and LdhD showed greatly reduced survival in neutrophils compared with wild type cells, highlighting the importance of D-lactate metabolism in gonococcal survival. Furthermore, an assay of host colonization using the well-established human primary cervical epithelial cell model revealed that the two respiratory enzymes make a significant contribution to colonization of and survival within the microaerobic environment of the host. Taken together, these data suggest that host-derived lactate is critical for the growth and survival of N. gonorrhoeae in human cells. PMID:24737798

  12. Miniaturised enzymatic conductometric biosensor with Nafion membrane for the direct determination of formaldehyde in water samples.

    PubMed

    Nguyen-Boisse, Thanh-Thuy; Saulnier, Joëlle; Jaffrezic-Renault, Nicole; Lagarde, Florence

    2014-02-01

    A new conductometric enzyme-based biosensor was developed for the determination of formaldehyde (FA) in aqueous solutions. The biosensor was prepared by cross-linking formaldehyde dehydrogenase from Pseudomonas putida with bovine serum albumin in saturated glutaraldehyde vapours (GA) at the surface of interdigitated gold microelectrodes. Nicotinamide adenine dinucleotide cofactor (NAD(+)) was added in solution at each measurement to maintain enzyme activity. Addition of a Nafion layer over the enzyme modified electrode resulted in a significant increase of biosensor signal due to enhanced accumulation of protons generated by enzymatic reaction at the electrode surface. Different parameters affecting enzyme activity or playing a role in ionic transfer through the Nafion membrane were optimised. In optimal conditions (0.045 mg enzyme, 30 min exposure to GA, 0.3 μL of a 1% (v/v) Nafion solution deposit, measurement in 5 mM phosphate buffer pH 7 containing 20 μM NAD(+)), the biosensor signal was linear up to 10 mM FA, and the detection limit was 18 μM. Relative standard deviations calculated from five consecutive replicates of FA solutions were lower than 5% in the 1-10 mM range. The biosensor was successfully applied to the determination of FA in spiked water samples (tap water and Rhone river water), with recoveries in the 95-110% range. PMID:23907681

  13. Separate physiological roles for two isozymes of pyridine nucleotide-linked glycerol-3-phosphate dehydrogenase in chicken.

    NASA Technical Reports Server (NTRS)

    White, H. B., III; Kaplan, N. O.

    1972-01-01

    The isozymes considered are designated 'liver type' and 'muscle type' based on the tissue of highest concentration. Electrophoretic analysis shows that the liver type is found in small amounts or is undetectable in all tissues studied except liver. The muscle type is found in skeletal muscles and kidney. Presumptive hybrid enzymes occur at low levels in chicken liver and kidney. The tissue distribution of glyceron-3-P dehydrogenase in several birds capable of sustained flight is different than in chicken.

  14. The specific role of plastidial glycolysis in photosynthetic and heterotrophic cells under scrutiny through the study of glyceraldehyde-3-phosphate dehydrogenase.

    PubMed

    Anoman, Armand Djoro; Flores-Tornero, María; Rosa-Telléz, Sara; Muñoz-Bertomeu, Jesús; Segura, Juan; Ros, Roc

    2016-01-01

    The cellular compartmentalization of metabolic processes is an important feature in plants where the same pathways could be simultaneously active in different compartments. Plant glycolysis occurs in the cytosol and plastids of green and non-green cells in which the requirements of energy and precursors may be completely different. Because of this, the relevance of plastidial glycolysis could be very different depending on the cell type. In the associated study, we investigated the function of plastidial glycolysis in photosynthetic and heterotrophic cells by specifically driving the expression of plastidial glyceraldehyde-3-phosphate dehydrogenase (GAPCp) in a glyceraldehyde-3-phosphate dehydrogenase double mutant background (gapcp1gapcp2). We showed that GAPCp is not functionally significant in photosynthetic cells, while it plays a crucial function in heterotrophic cells. We also showed that (i) GAPCp activity expression in root tips is necessary for primary root growth, (ii) its expression in heterotrophic cells of aerial parts and roots is necessary for plant growth and development, and (iii) GAPCp is an important metabolic connector of carbon and nitrogen metabolism through the phosphorylated pathway of serine biosynthesis (PPSB). We discuss here the role that this pathway could play in the control of plant growth and development. PMID:26953506

  15. Production of formaldehyde by detergent-treated cells of a methanol yeast, Candida boidinii S2 mutant strain AOU-1

    SciTech Connect

    Sakai, Y.; Tani, Y.

    1988-02-01

    Treatment of cells of a methanol yeast, Candida boidinii, with the cationic detergent cetyldimethylbenzyl-ammonium chloride (cation M2) improved the production of formaldehyde. Formaldehyde production was improved twofold with respect to the initial amount of formaldehyde and 1.61-fold with respect to the final amount of formaldehyde after a 12-h reaction under optimized detergent treatment conditions. The treatment caused formaldehyde and formate dehydrogenases to leak out of the cells more rapidly than catalase, but there was no leakage of alcohol oxidase. The improvement in formaldehyde production was considered to be due to the increased permeability of yeast cell membranes and to lower activities of formaldehyde and formate dehydrogenases in Cation M2-treated cells than in intact cells. Changes in the ultrastructure of the cells were observed upon Cation M2 treatment. Several developed peroxisomes were observed in intact cells. After Cation M2 treatment, the cells were obviously damaged, and several peroxisomes seemed to have fused with each other.

  16. Cyanobacterial NADPH dehydrogenase complexes

    SciTech Connect

    Ogawa, Teruo; Mi, Hualing

    2007-07-01

    Cyanobacteria possess functionally distinct multiple NADPH dehydrogenase (NDH-1) complexes that are essential to CO2 uptake, photosystem-1 cyclic electron transport and respiration. The unique nature of cyanobacterial NDH-1 complexes is the presence of subunits involved in CO2 uptake. Other than CO2 uptake, chloroplastic NDH-1 complex has similar role as cyanobacterial NDH-1 complexes in photosystem-1 cyclic electron transport and respiration (chlororespiration). In this mini-review we focus on the structure and function of cyanobacterial NDH-1 complexes and their phylogeny. The function of chloroplastic NDH-1 complex and characteristics of plants defective in NDH-1 are also described forcomparison.

  17. Reconfiguration of N Metabolism upon Hypoxia Stress and Recovery: Roles of Alanine Aminotransferase (AlaAT) and Glutamate Dehydrogenase (GDH)

    PubMed Central

    Diab, Houssein; Limami, Anis M.

    2016-01-01

    In the context of climatic change, more heavy precipitation and more frequent flooding and waterlogging events threaten the productivity of arable farmland. Furthermore, crops were not selected to cope with flooding- and waterlogging-induced oxygen limitation. In general, low oxygen stress, unlike other abiotic stresses (e.g., cold, high temperature, drought and saline stress), received little interest from the scientific community and less financial support from stakeholders. Accordingly, breeding programs should be developed and agronomical practices should be adapted in order to save plants’ growth and yield—even under conditions of low oxygen availability (e.g., submergence and waterlogging). The prerequisite to the success of such breeding programs and changes in agronomical practices is a good knowledge of how plants adapt to low oxygen stress at the cellular and the whole plant level. In the present paper, we summarized the recent knowledge on metabolic adjustment in general under low oxygen stress and highlighted thereafter the major changes pertaining to the reconfiguration of amino acids syntheses. We propose a model showing (i) how pyruvate derived from active glycolysis upon hypoxia is competitively used by the alanine aminotransferase/glutamate synthase cycle, leading to alanine accumulation and NAD+ regeneration. Carbon is then saved in a nitrogen store instead of being lost through ethanol fermentative pathway. (ii) During the post-hypoxia recovery period, the alanine aminotransferase/glutamate dehydrogenase cycle mobilizes this carbon from alanine store. Pyruvate produced by the reverse reaction of alanine aminotransferase is funneled to the TCA cycle, while deaminating glutamate dehydrogenase regenerates, reducing equivalent (NADH) and 2-oxoglutarate to maintain the cycle function. PMID:27258319

  18. Reconfiguration of N Metabolism upon Hypoxia Stress and Recovery: Roles of Alanine Aminotransferase (AlaAT) and Glutamate Dehydrogenase (GDH).

    PubMed

    Diab, Houssein; Limami, Anis M

    2016-01-01

    In the context of climatic change, more heavy precipitation and more frequent flooding and waterlogging events threaten the productivity of arable farmland. Furthermore, crops were not selected to cope with flooding- and waterlogging-induced oxygen limitation. In general, low oxygen stress, unlike other abiotic stresses (e.g., cold, high temperature, drought and saline stress), received little interest from the scientific community and less financial support from stakeholders. Accordingly, breeding programs should be developed and agronomical practices should be adapted in order to save plants' growth and yield-even under conditions of low oxygen availability (e.g., submergence and waterlogging). The prerequisite to the success of such breeding programs and changes in agronomical practices is a good knowledge of how plants adapt to low oxygen stress at the cellular and the whole plant level. In the present paper, we summarized the recent knowledge on metabolic adjustment in general under low oxygen stress and highlighted thereafter the major changes pertaining to the reconfiguration of amino acids syntheses. We propose a model showing (i) how pyruvate derived from active glycolysis upon hypoxia is competitively used by the alanine aminotransferase/glutamate synthase cycle, leading to alanine accumulation and NAD⁺ regeneration. Carbon is then saved in a nitrogen store instead of being lost through ethanol fermentative pathway. (ii) During the post-hypoxia recovery period, the alanine aminotransferase/glutamate dehydrogenase cycle mobilizes this carbon from alanine store. Pyruvate produced by the reverse reaction of alanine aminotransferase is funneled to the TCA cycle, while deaminating glutamate dehydrogenase regenerates, reducing equivalent (NADH) and 2-oxoglutarate to maintain the cycle function. PMID:27258319

  19. Role of the glutamate dehydrogenase reaction in furnishing aspartate nitrogen for urea synthesis: studies in perfused rat liver with 15N.

    PubMed Central

    Nissim, Itzhak; Horyn, Oksana; Luhovyy, Bohdan; Lazarow, Adam; Daikhin, Yevgeny; Nissim, Ilana; Yudkoff, Marc

    2003-01-01

    The present study was designed to determine: (i) the role of the reductive amination of alpha-ketoglutarate via the glutamate dehydrogenase reaction in furnishing mitochondrial glutamate and its transamination into aspartate; (ii) the relative incorporation of perfusate 15NH4Cl, [2-15N]glutamine or [5-15N]glutamine into carbamoyl phosphate and aspartate-N and, thereby, [15N]urea isotopomers; and (iii) the extent to which perfusate [15N]aspartate is taken up by the liver and incorporated into [15N]urea. We used a liver-perfusion system containing a physiological mixture of amino acids and ammonia similar to concentrations in vivo, with 15N label only in glutamine, ammonia or aspartate. The results demonstrate that in perfusions with a physiological mixture of amino acids, approx. 45 and 30% of total urea-N output was derived from perfusate ammonia and glutamine-N respectively. Approximately two-thirds of the ammonia utilized for carbamoyl phosphate synthesis was derived from perfusate ammonia and one-third from glutamine. Perfusate [2-15N]glutamine, [5-15N]glutamine or [15N]aspartate provided 24, 10 and 10% respectively of the hepatic aspartate-N pool, whereas perfusate 15NH4Cl provided approx. 37% of aspartate-N utilized for urea synthesis, secondary to the net formation of [15N]glutamate via the glutamate dehydrogenase reaction. The results suggest that the mitochondrial glutamate formed via the reductive amination of alpha-ketoglutarate may have a key role in ammonia detoxification by the following processes: (i) furnishing aspartate-N for ureagenesis; (ii) serving as a scavenger for excess ammonia; and (iii) improving the availability of the mitochondrial [glutamate] for synthesis of N -acetylglutamate. In addition, the current findings suggest that the formation of aspartate via the mitochondrial aspartate aminotransferase reaction may play an important role in the synthesis of cytosolic argininosuccinate. PMID:12935293

  20. Identification of an arginine residue in the dual coenzyme-specific glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides that plays a key role in binding NADP+ but not NAD+.

    PubMed

    Levy, H R; Vought, V E; Yin, X; Adams, M J

    1996-02-01

    Glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides can utilize either NADP or NAD as coenzyme. The enzyme's three-dimensional structure has been solved (Rowland et al., 1994, Structure 2, 1073-1087) and shown to contain a conventional nucleotide binding domain. NADP+ was modeled into the structure by superimposing the beta alpha beta domain and that of coenzyme-bound 6-phosphogluconate dehydrogenase (Adams et al., 1994, Structure 2, 651-658), enabling us to identify Arg-46 as a potentially important residue for NADP+ binding. Using site-directed mutagenesis, we constructed mutant enzymes in which Arg-46 was replaced by glutamine (R46Q) and alanine (R46A) and examined their kinetic properties. The principal effects in these mutant enzymes were that the Km and Ki values for NADP+ increased by 2 to 3 orders of magnitude over those of the wild-type enzyme. No other kinetic constant was altered more than 6.5-fold. Changing this single amino acid leads to mutant glucose-6-phosphate dehydrogenases with coenzyme specificities that favor NAD+, whereas the wild-type enzyme prefers NADP+ as coenzyme. These results confirm that Arg-46 plays a key role in NADP+ binding by contributing a positively charged planar residue that interacts primarily with the 2'-adenosine phosphate. The Arg residue corresponding to Arg-46 in L. mesenteroides glucose-6-phosphate dehydrogenase is conserved in all glucose-6-phosphate dehydrogenases and, presumably, plays the same role in all these enzymes. PMID:8579362

  1. Detoxification of Formaldehyde by the Spider Plant (Chlorophytum comosum L.) and by Soybean (Glycine max L.) Cell-Suspension Cultures.

    PubMed Central

    Giese, M.; Bauer-Doranth, U.; Langebartels, C.; Sandermann, H.

    1994-01-01

    The phytotoxicity of formaldehyde for spider plants (Chlorophytum comosum L.), tobacco plants (Nicotiana tabacum L. cv Bel B and Bel W3), and soybean (Glycine max L.) cell-suspension cultures was found to be low enough to allow metabolic studies. Spider plant shoots were exposed to 7.1 [mu]L L-1 (8.5 mg m-3) gaseous [14C]-formaldehyde over 24 h. Approximately 88% of the recovered radioactivity was plant associated and was found to be incorporated into organic acids, amino acids, free sugars, and lipids as well as cell-wall components. Similar results were obtained upon feeding [14C]formaldehyde from aqueous solution to aseptic soybean cell-suspension cultures. Serine and phosphatidylcholine were identified as major metabolic products. Spider plant enzyme extracts contained two NAS+-dependent formaldehyde dehydrogenase activities with molecular mass values of about 129 and 79 kD. Only the latter enzyme activity required glutathione as an obligatory second cofactor. It had an apparent Km value of 30 [mu]M for formaldehyde and an isoelectric point at pH 5.4. Total cell-free dehydrogenase activity corresponded to 13 [mu]g formaldehyde oxidized h-1 g-1 leaf fresh weight. Glutathione-dependent formaldehyde dehydrogenases were also isolated from shoots and leaves of Equisetum telmateia and from cell-suspension cultures of wheat (Triticum aestivum L.) and maize (Zea mays L.). The results obtained are consistent with the concept of indoor air decontamination with common room plants such as the spider plant. Formaldehyde appears to be efficiently detoxified by oxidation and subsequent C1 metabolism. PMID:12232169

  2. The Role of Dihydroorotate Dehydrogenase in Apoptosis Induction in Response to Inhibition of the Mitochondrial Respiratory Chain Complex III

    PubMed Central

    Khutornenko, A. A.; Dalina, A. A.; Chernyak, B. V.; Chumakov, P. M.; Evstafieva, A. G.

    2014-01-01

    A mechanism for the induction of programmed cell death (apoptosis) upon dysfunction of the mitochondrial respiratory chain has been studied. Previously, we had found that inhibition of mitochondrial cytochrome bc1, a component of the electron transport chain complex III, leads to activation of tumor suppressor p53, followed by apoptosis induction. The mitochondrial respiratory chain is coupled to the de novo pyrimidine biosynthesis pathway via the mitochondrial enzyme dihydroorotate dehydrogenase (DHODH). The p53 activation induced in response to the inhibition of the electron transport chain complex III has been shown to be triggered by the impairment of the de novo pyrimidine biosynthesis due to the suppression of DHODH. However, it remained unclear whether the suppression of the DHODH function is the main cause of the observed apoptotic cell death. Here, we show that apoptosis in human colon carcinoma cells induced by the mitochondrial respiratory chain complex III inhibition can be prevented by supplementation with uridine or orotate (products of the reaction catalyzed by DHODH) rather than with dihydroorotate (a DHODH substrate). We conclude that apoptosis is induced in response to the impairment of the de novo pyrimidine biosynthesis caused by the inhibition of DHODH. The conclusion is supported by the experiment showing that downregulation of DHODH by RNA interference leads to accumulation of the p53 tumor suppressor and to apoptotic cell death. PMID:24772329

  3. A Catalytic Role of XoxF1 as La3+-Dependent Methanol Dehydrogenase in Methylobacterium extorquens Strain AM1

    PubMed Central

    Sasa, Kentaro; Tashiro, Shinya; Iwama, Tomonori; Hayakawa, Takashi; Kawai, Keiichi

    2012-01-01

    In the methylotrophic bacterium Methylobacterium extorquens strain AM1, MxaF, a Ca2+-dependent methanol dehydrogenase (MDH), is the main enzyme catalyzing methanol oxidation during growth on methanol. The genome of strain AM1 contains another MDH gene homologue, xoxF1, whose function in methanol metabolism has remained unclear. In this work, we show that XoxF1 also functions as an MDH and is La3+-dependent. Despite the absence of Ca2+ in the medium strain AM1 was able to grow on methanol in the presence of La3+. Addition of La3+ increased MDH activity but the addition had no effect on mxaF or xoxF1 expression level. We purified MDH from strain AM1 grown on methanol in the presence of La3+, and its N-terminal amino acid sequence corresponded to that of XoxF1. The enzyme contained La3+ as a cofactor. The ΔmxaF mutant strain could not grow on methanol in the presence of Ca2+, but was able to grow after supplementation with La3+. Taken together, these results show that XoxF1 participates in methanol metabolism as a La3+-dependent MDH in strain AM1. PMID:23209751

  4. Glucose-6-phosphate dehydrogenase

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003671.htm Glucose-6-phosphate dehydrogenase test To use the sharing features on this page, please enable JavaScript. Glucose-6-phosphate dehydrogenase (G6PD) is a type of ...

  5. Catalytic process for formaldehyde oxidation

    NASA Technical Reports Server (NTRS)

    Kielin, Erik J. (Inventor); Brown, Kenneth G. (Inventor); D'Ambrosia, Christine M. (Inventor)

    1996-01-01

    Disclosed is a process for oxidizing formaldehyde to carbon dioxide and water without the addition of energy. A mixture of formaldehyde and an oxidizing agent (e.g., ambient air containing formaldehyde) is exposed to a catalyst which includes a noble metal dispersed on a metal oxide which possesses more than one oxidation state. Especially good results are obtained when the noble metal is platinum, and the metal oxide which possesses more than one oxidation state is tin oxide. A promoter (i.e., a small amount of an oxide of a transition series metal) may be used in association with the tin oxide to provide very beneficial results.

  6. Sporostatic and sporocidal properties of aqueous formaldehyde.

    NASA Technical Reports Server (NTRS)

    Trujillo, R.; David, T. J.

    1972-01-01

    Aqueous formaldehyde is shown to exert both sporostatic and sporocidal effects on Bacillus subtilis spores. The sporostatic effect is a result of the reversible inhibition of spore germination occasioned by aqueous formaldehyde; the sporocidal effect is due to the temperature-dependent inactivation of these spores in aqueous formaldehyde. The physicochemical state of formaldehyde in solution provides a framework with which to interpret both the sporostatic and sporocidal properties of aqueous formaldehyde.

  7. Photoabsorption in formaldehyde

    NASA Technical Reports Server (NTRS)

    Langhoff, P. W.; Langhoff, S. R.; Corcoran, C. T.

    1977-01-01

    Theoretical studies of the vertical electronic dipole excitation and ionization spectra in molecular formaldehyde are reported. The investigations relied on configuration-interaction calculations and moment-theory techniques. A double-zeta basis of contracted Gaussian-lobe functions supplemented with appropriate polarization and bond functions was used to construct Fock spectra in C(2 nu) symmetry for certain states near the ground state equilibrium geometry. The ionization energies, discrete vertical transition frequencies, and oscillator strengths for occupied and vertical Fock orbitals are in general accord with experimental determinations and other theoretical calculations. Stieltjes and Chebyshev vertical electronic photoionization profiles were calculated and found to be in good agreement with appropriately averaged photoionization-mass spectrometric measurements of the cross section for parent H2CO(+) ion production.

  8. Importance of formaldehyde in cloud chemistry

    NASA Technical Reports Server (NTRS)

    Adewuyi, Y. G.; Cho, S.-Y.; Tsay, R.-P.; Carmichael, G. R.

    1984-01-01

    A physical-chemical model which is an extension of that of Hong and Carmichael (1983) is used to investigate the role of formaldehyde in cloud chemistry. This model takes into account the mass transfer of SO2, O3, NH3, HNO3, H2O2, CO2, HCl, HCHO, O2, OH and HO2 into cloud droplets and their subsequent chemical reactions. The model is used to assess the importance of S(IV)-HCHO adduct formation, the reduction of H2O2 by HCHO, HCHO-free radical interactions, and the formation of HCOOH in the presence of HCHO in cloud droplets. Illustrative calculations indicate that the presence of HCHO inhibits sulfate production rate in cloud droplets. The direct inhibition of sulfate production rate in cloudwater due to nucleophilic addition of HSO3(-) to HCHO(aq) to form hydroxymethanesulfonate is generally low for concentrations of HCHO typical of ambient air. However, inhibition of sulfate production due to formaldehyde-free radical interactions in solution can be important. These formaldehyde-free radical reactions can also generate appreciable quantities of formic acid.

  9. Overcompensation in Response to Herbivory in Arabidopsis thaliana: The Role of Glucose-6-Phosphate Dehydrogenase and the Oxidative Pentose-Phosphate Pathway

    PubMed Central

    Siddappaji, Madhura H.; Scholes, Daniel R.; Bohn, Martin; Paige, Ken N.

    2013-01-01

    That some plants benefit from being eaten is counterintuitive, yet there is now considerable evidence demonstrating enhanced fitness following herbivory (i.e., plants can overcompensate). Although there is evidence that genetic variation for compensation exists, little is known about the genetic mechanisms leading to enhanced growth and reproduction following herbivory. We took advantage of the compensatory variation in recombinant inbred lines of Arabidopsis thaliana, combined with microarray and QTL analyses to assess the molecular basis of overcompensation. We found three QTL explaining 11.4, 10.1, and 26.7% of the variation in fitness compensation, respectively, and 109 differentially expressed genes between clipped and unclipped plants of the overcompensating ecotype Columbia. From the QTL/microarray screen we uncovered one gene that plays a significant role in overcompensation: glucose-6-phosphate-1-dehydrogenase (G6PDH1). Knockout studies of Transfer-DNA (T-DNA) insertion lines and complementation studies of G6PDH1 verify its role in compensation. G6PDH1 is a key enzyme in the oxidative pentose-phosphate pathway that plays a central role in plant metabolism. We propose that plants capable of overcompensating reprogram their transcriptional activity by up-regulating defensive genes and genes involved in energy metabolism and by increasing DNA content (via endoreduplication) with the increase in DNA content feeding back on pathways involved in defense and metabolism through increased gene expression. PMID:23934891

  10. Metabolomic profile of glycolysis and the pentose phosphate pathway identifies the central role of glucose-6-phosphate dehydrogenase in clear cell-renal cell carcinoma

    PubMed Central

    Sanguedolce, Francesca; Cagiano, Simona; Bufo, Pantaleo; Lastilla, Gaetano; Maiorano, Eugenio; Ribatti, Domenico; Giglio, Andrea; Serino, Grazia; Vavallo, Antonio; Bettocchi, Carlo; Selvaggi, Francesco Paolo; Battaglia, Michele; Ditonno, Pasquale

    2015-01-01

    The analysis of cancer metabolome has shown that proliferating tumor cells require a large quantities of different nutrients in order to support their high rate of proliferation. In this study we analyzed the metabolic profile of glycolysis and the pentose phosphate pathway (PPP) in human clear cell-renal cell carcinoma (ccRCC) and evaluate the role of these pathways in sustaining cell proliferation, maintenance of NADPH levels, and production of reactive oxygen species (ROS). Metabolomic analysis showed a clear signature of increased glucose uptake and utilization in ccRCC tumor samples. Elevated levels of glucose-6-phosphate dehydrogenase (G6PDH) in association with higher levels of PPP-derived metabolites, suggested a prominent role of this pathway in RCC-associated metabolic alterations. G6PDH inhibition, caused a significant decrease in cancer cell survival, a decrease in NADPH levels, and an increased production of ROS, suggesting that the PPP plays an important role in the regulation of ccRCC redox homeostasis. Patients with high levels of glycolytic enzymes had reduced progression-free and cancer-specific survivals as compared to subjects with low levels. Our data suggest that oncogenic signaling pathways may promote ccRCC through rerouting the sugar metabolism. Blocking the flux through this pathway may serve as a novel therapeutic target. PMID:25945836

  11. Role of Packing Defects in the Evolution of Allostery and Induced Fit in Human UDP-Glucose Dehydrogenase

    SciTech Connect

    Kadirvelraj, Renuka; Sennett, Nicholas C.; Polizzi, Samuel J.; Weitzel, Stephen; Wood, Zachary A.

    2012-05-25

    Allosteric feedback inhibition is the mechanism by which metabolic end products regulate their own biosynthesis by binding to an upstream enzyme. Despite its importance in controlling metabolism, there are relatively few allosteric mechanisms understood in detail. This is because allostery does not have an identifiable structural motif, making the discovery of new allosteric enzymes a difficult process. The lack of a conserved motif implies that the evolution of each allosteric mechanism is unique. Here we describe an atypical allosteric mechanism in human UDP-{alpha}-D-glucose 6-dehydrogenase (hUGDH) based on an easily acquired and identifiable structural attribute: packing defects in the protein core. In contrast to classic allostery, the active and allosteric sites in hUGDH are present as a single, bifunctional site. Using two new crystal structures, we show that binding of the feedback inhibitor, UDP-{alpha}-D-xylose, elicits a distinct induced-fit response; a buried loop translates {approx}4 {angstrom} along and rotates {approx}180{sup o} about the main chain axis, requiring surrounding side chains to repack. This allosteric transition is facilitated by packing defects, which negate the steric conformational restraints normally imposed by the protein core. Sedimentation velocity studies show that this repacking favors the formation of an inactive hexameric complex with unusual symmetry. We present evidence that hUGDH and the unrelated enzyme dCTP deaminase have converged to very similar atypical allosteric mechanisms using the same adaptive strategy, the selection for packing defects. Thus, the selection for packing defects is a robust mechanism for the evolution of allostery and induced fit.

  12. Local Glucocorticoid Activation by 11β-Hydroxysteroid Dehydrogenase 1 in Keratinocytes: The Role in Hapten-Induced Dermatitis.

    PubMed

    Terao, Mika; Itoi, Saori; Matsumura, Sayaka; Yang, Lingli; Murota, Hiroyuki; Katayama, Ichiro

    2016-06-01

    Over the past decade, extra-adrenal cortisol production was reported in various tissues. The enzyme that catalyzes the conversion of hormonally inactive cortisone into active cortisol in cells is 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1). We recently reported that 11β-HSD1 is also expressed in keratinocytes and regulates inflammation and keratinocyte proliferation. To investigate the function of 11β-HSD1 in keratinocytes during inflammation in vivo, we created keratinocyte-specific 11β-HSD1 knockout (K5-Hsd11b1-KO) mice and analyzed the inflammatory response in models of hapten-induced contact irritant dermatitis. K5-Hsd11b1-KO mice showed enhanced ear swelling in low-dose oxazolone-, 2,4,6-trinitro-1-chlorobenzene (TNCB)-, and 2,4-dinitrofluorobenzene-induced irritant dermatitis associated with increased inflammatory cell infiltration. Topical application of corticosterone dose dependently suppressed TNCB-induced ear swelling and cytokine expression. Similarly in mouse keratinocytes in vitro, corticosterone dose dependently suppressed 2,4,6-trinitrobenzenesulfonic acid-induced IL-1α and IL-1β expression. The effect of 11-dehydrocorticosterone was attenuated in TNCB-induced irritant dermatitis in K5-Hsd11b1-KO mice compared with wild-type mice. In human samples, 11β-HSD1 expression was decreased in epidermis of psoriasis vulgaris compared with healthy skin. Taken together, these data suggest that corticosterone activation by 11β-HSD1 in keratinocytes suppresses hapten-induced irritant dermatitis through suppression of expression of cytokines, such as IL-1α and IL-1β, in keratinocytes. PMID:27070821

  13. Visualization of Molecular Orbitals: Formaldehyde

    ERIC Educational Resources Information Center

    Olcott, Richard J.

    1972-01-01

    Describes a computer program that plots a solid" representation of molecular orbital charge density which can be used to analyze wave functions of molecules. Illustrated with diagrams for formaldehyde. (AL)

  14. Formaldehyde Gas Sensors: A Review

    PubMed Central

    Chung, Po-Ren; Tzeng, Chun-Ta; Ke, Ming-Tsun; Lee, Chia-Yen

    2013-01-01

    Many methods based on spectrophotometric, fluorometric, piezoresistive, amperometric or conductive measurements have been proposed for detecting the concentration of formaldehyde in air. However, conventional formaldehyde measurement systems are bulky and expensive and require the services of highly-trained operators. Accordingly, the emergence of sophisticated technologies in recent years has prompted the development of many microscale gaseous formaldehyde detection systems. Besides their compact size, such devices have many other advantages over their macroscale counterparts, including a real-time response, a more straightforward operation, lower power consumption, and the potential for low-cost batch production. This paper commences by providing a high level overview of the formaldehyde gas sensing field and then describes some of the more significant real-time sensors presented in the literature over the past 10 years or so. PMID:23549368

  15. Dual Role of the Active Site Residues of Thermus thermophilus 3-Isopropylmalate Dehydrogenase: Chemical Catalysis and Domain Closure.

    PubMed

    Gráczer, Éva; Szimler, Tamás; Garamszegi, Anita; Konarev, Petr V; Lábas, Anikó; Oláh, Julianna; Palló, Anna; Svergun, Dmitri I; Merli, Angelo; Závodszky, Péter; Weiss, Manfred S; Vas, Mária

    2016-01-26

    The key active site residues K185, Y139, D217, D241, D245, and N102 of Thermus thermophilus 3-isopropylmalate dehydrogenase (Tt-IPMDH) have been replaced, one by one, with Ala. A drastic decrease in the kcat value (0.06% compared to that of the wild-type enzyme) has been observed for the K185A and D241A mutants. Similarly, the catalytic interactions (Km values) of these two mutants with the substrate IPM are weakened by more than 1 order of magnitude. The other mutants retained some (1-13%) of the catalytic activity of the wild-type enzyme and do not exhibit appreciable changes in the substrate Km values. The pH dependence of the wild-type enzyme activity (pK = 7.4) is shifted toward higher values for mutants K185A and D241A (pK values of 8.4 and 8.5, respectively). For the other mutants, smaller changes have been observed. Consequently, K185 and D241 may constitute a proton relay system that can assist in the abstraction of a proton from the OH group of IPM during catalysis. Molecular dynamics simulations provide strong support for the neutral character of K185 in the resting state of the enzyme, which implies that K185 abstracts the proton from the substrate and D241 assists the process via electrostatic interactions with K185. Quantum mechanics/molecular mechanics calculations revealed a significant increase in the activation energy of the hydride transfer of the redox step for both D217A and D241A mutants. Crystal structure analysis of the molecular contacts of the investigated residues in the enzyme-substrate complex revealed their additional importance (in particular that of K185, D217, and D241) in stabilizing the domain-closed active conformation. In accordance with this, small-angle X-ray scattering measurements indicated the complete absence of domain closure in the cases of D217A and D241A mutants, while only partial domain closure could be detected for the other mutants. This suggests that the same residues that are important for catalysis are also

  16. Characterization of the Rana grylio virus 3{beta}-hydroxysteroid dehydrogenase and its novel role in suppressing virus-induced cytopathic effect

    SciTech Connect

    Sun Wei; Huang Youhua; Zhao Zhe; Gui Jianfang; Zhang Qiya . E-mail: zhangqy@ihb.ac.cn

    2006-12-08

    The 3{beta}-hydroxysteroid dehydrogenase (3{beta}-HSD) isoenzymes play a key role in cellular steroid hormone synthesis. Here, a 3{beta}-HSD gene homolog was cloned from Rana grylio virus (RGV), a member of family Iridoviridae. RGV 3{beta}-HSD gene has 1068 bp, encoding a 355 aa predicted protein. Transcription analyses showed that RGV 3{beta}-HSD gene was transcribed immediate-early during infection from an initiation site 19 nucleotides upstream of the translation start site. Confocal microscopy revealed that the 3{beta}-HSD-EGFP fusion protein was exclusively colocalized with the mitochondria marker (pDsRed2-Mito) in EPC cells. Upon morphological observation and MTT assay, it was revealed that overexpression of RGV 3{beta}-HSD in EPC cells could apparently suppress RGV-induced cytopathic effect (CPE). The present studies indicate that the RGV immediate-early 3{beta}-HSD gene encodes a mitochondria-localized protein, which has a novel role in suppressing virus-induced CPE. All these suggest that RGV 3{beta}-HSD might be a protein involved in host-virus interaction.

  17. Does formaldehyde induce aneuploidy?

    PubMed

    Speit, Günter; Kühner, Stefanie; Linsenmeyer, Regina; Schütz, Petra

    2011-11-01

    Formaldehyde (FA) was tested for a potential aneugenic activity in mammalian cells. We employed tests to discriminate between aneugenic and clastogenic effects in accordance with international guidelines for genotoxicity testing. The cytokinesis-block micronucleus test (CBMNT) in combination with fluorescence in situ hybridisation (FISH) with a pan-centromeric probe was performed with cultured human lymphocytes and the human A549 lung cell line. FA induced micronuclei (MN) in binuclear cells of both cell types under standard in vitro test conditions following the OECD guideline 487. FISH analysis revealed that the vast majority of induced MN were centromere negative, thus indicating a clastogenic effect. A similar result was obtained for MN induced by γ-irradiation, whereas the typical aneugens colcemid (COL) and vincristine (VCR) predominantly induced centromere-positive MN. Furthermore, COL and VCR clearly enhanced the MN frequency in mononuclear lymphocytes in the CBMNT, whereas such an effect was not observed for γ-irradiation and FA. In experiments with the Chinese hamster V79 cell line, the aneugens COL and VCR clearly increased the frequency of tetraploid second division metaphases, whereas FA did not cause such an effect. Altogether, our results confirm the clastogenicity of FA in cultured mammalian cells but exclude a significant aneugenic activity. PMID:21804075

  18. Glucose-6-phosphate dehydrogenase plays a central role in the response of tomato (Solanum lycopersicum) plants to short and long-term drought.

    PubMed

    Landi, Simone; Nurcato, Roberta; De Lillo, Alessia; Lentini, Marco; Grillo, Stefania; Esposito, Sergio

    2016-08-01

    The present study was undertaken to investigate the expression, occurrence and activity of glucose 6 phosphate dehydrogenase (G6PDH - EC 1.1.1.49), the key-enzyme of the Oxidative Pentose Phosphate Pathway (OPPP), in tomato plants (Solanum lycopersicum cv. Red Setter) exposed to short- and long-term drought stress. For the first time, drought effects have been evaluated in plants under different growth conditions: in hydroponic laboratory system, and in greenhouse pots under controlled conditions; and in open field, in order to evaluate drought response in a representative agricultural environment. Interestingly, changes observed appear strictly associated to the induction of well known stress response mechanisms, such as the increase of proline synthesis, accumulation of chaperone Hsp70, and ascorbate peroxidase. Results show significant increase in total activity of G6PDH, and specifically in expression and occurrence of cytosolic isoform (cy-G6PDH) in plants grown in any cultivation system upon drought. Intriguingly, the results clearly suggest that abscissic acid (ABA) pathway and signaling cascade (protein phosphatase 2C PP2C) could be strictly related to increased G6PDH expression, occurrence and activities. We hypothesized for G6PDH a specific role as one of the main reductants' suppliers to counteract the effects of drought stress, in the light of converging evidences given by young and adult tomato plants under stress of different duration and intensity. PMID:27085599

  19. Photosystem I cyclic electron flow via chloroplast NADH dehydrogenase-like complex performs a physiological role for photosynthesis at low light

    PubMed Central

    Yamori, Wataru; Shikanai, Toshiharu; Makino, Amane

    2015-01-01

    Cyclic electron transport around photosystem I (PS I) was discovered more than a half-century ago and two pathways have been identified in angiosperms. Although substantial progress has been made in understanding the structure of the chloroplast NADH dehydrogenase-like (NDH) complex, which mediates one route of the cyclic electron transport pathways, its physiological function is not well understood. Most studies focused on the role of the NDH-dependent PS I cyclic electron transport in alleviation of oxidative damage in strong light. In contrast, here it is shown that impairment of NDH-dependent cyclic electron flow in rice specifically causes a reduction in the electron transport rate through PS I (ETR I) at low light intensity with a concomitant reduction in CO2 assimilation rate, plant biomass and importantly, grain production. There was no effect on PS II function at low or high light intensity. We propose a significant physiological function for the chloroplast NDH at low light intensities commonly experienced during the reproductive and ripening stages of rice cultivation that have adverse effects crop yield. PMID:26358849

  20. Characterization of a NADH-Dependent Glutamate Dehydrogenase Mutant of Arabidopsis Demonstrates the Key Role of this Enzyme in Root Carbon and Nitrogen Metabolism[W

    PubMed Central

    Fontaine, Jean-Xavier; Tercé-Laforgue, Thérèse; Armengaud, Patrick; Clément, Gilles; Renou, Jean-Pierre; Pelletier, Sandra; Catterou, Manuella; Azzopardi, Marianne; Gibon, Yves; Lea, Peter J.; Hirel, Bertrand; Dubois, Frédéric

    2012-01-01

    The role of NADH-dependent glutamate dehydrogenase (GDH) was investigated by studying the physiological impact of a complete lack of enzyme activity in an Arabidopsis thaliana plant deficient in three genes encoding the enzyme. This study was conducted following the discovery that a third GDH gene is expressed in the mitochondria of the root companion cells, where all three active GDH enzyme proteins were shown to be present. A gdh1-2-3 triple mutant was constructed and exhibited major differences from the wild type in gene transcription and metabolite concentrations, and these differences appeared to originate in the roots. By placing the gdh triple mutant under continuous darkness for several days and comparing it to the wild type, the evidence strongly suggested that the main physiological function of NADH-GDH is to provide 2-oxoglutarate for the tricarboxylic acid cycle. The differences in key metabolites of the tricarboxylic acid cycle in the triple mutant versus the wild type indicated that, through metabolic processes operating mainly in roots, there was a strong impact on amino acid accumulation, in particular alanine, γ-aminobutyrate, and aspartate in both roots and leaves. These results are discussed in relation to the possible signaling and physiological functions of the enzyme at the interface of carbon and nitrogen metabolism. PMID:23054470

  1. Characterization of a NADH-dependent glutamate dehydrogenase mutant of Arabidopsis demonstrates the key role of this enzyme in root carbon and nitrogen metabolism.

    PubMed

    Fontaine, Jean-Xavier; Tercé-Laforgue, Thérèse; Armengaud, Patrick; Clément, Gilles; Renou, Jean-Pierre; Pelletier, Sandra; Catterou, Manuella; Azzopardi, Marianne; Gibon, Yves; Lea, Peter J; Hirel, Bertrand; Dubois, Frédéric

    2012-10-01

    The role of NADH-dependent glutamate dehydrogenase (GDH) was investigated by studying the physiological impact of a complete lack of enzyme activity in an Arabidopsis thaliana plant deficient in three genes encoding the enzyme. This study was conducted following the discovery that a third GDH gene is expressed in the mitochondria of the root companion cells, where all three active GDH enzyme proteins were shown to be present. A gdh1-2-3 triple mutant was constructed and exhibited major differences from the wild type in gene transcription and metabolite concentrations, and these differences appeared to originate in the roots. By placing the gdh triple mutant under continuous darkness for several days and comparing it to the wild type, the evidence strongly suggested that the main physiological function of NADH-GDH is to provide 2-oxoglutarate for the tricarboxylic acid cycle. The differences in key metabolites of the tricarboxylic acid cycle in the triple mutant versus the wild type indicated that, through metabolic processes operating mainly in roots, there was a strong impact on amino acid accumulation, in particular alanine, γ-aminobutyrate, and aspartate in both roots and leaves. These results are discussed in relation to the possible signaling and physiological functions of the enzyme at the interface of carbon and nitrogen metabolism. PMID:23054470

  2. Role of quinones in electron transfer of PQQ–glucose dehydrogenase anodes—mediation or orientation effect

    SciTech Connect

    Babanova, Sofia; Matanovic, Ivana; Chavez, Madelaine Seow; Atanassov, Plamen

    2015-06-16

    In this study, the influence of two quinones (1,2- and 1,4-benzoquinone) on the operation and mechanism of electron transfer in PQQ-sGDH anodes has been determined. Benzoquinones were experimentally explored as mediators present in the electrolyte. The electrochemical performance of the PQQ–sGDH anodes with and without the mediators was examined and for the first time molecular docking simulations were used to gain a fundamental understanding to explain the role of the mediator molecules in the design and operation of the enzymatic electrodes. It was proposed that the higher performance of the PQQ–sGDH anodes in the presence of 1,2- and 1,4-benzoquinones introduced in the solution is due to the shorter distance between these molecules and PQQ in the enzymatic molecule. It was also hypothesized that when 1,4-benzoquinone is adsorbed on a carbon support, it would play the dual role of a mediator and an orienting agent. At the same time, when 1,2-benzoquinone and ubiquinone are adsorbed on the electrode surface, the enzyme would transfer the electrons directly to the support, and these molecules would primarily play the role of an orienting agent.

  3. Role of quinones in electron transfer of PQQ–glucose dehydrogenase anodes—mediation or orientation effect

    DOE PAGESBeta

    Babanova, Sofia; Matanovic, Ivana; Chavez, Madelaine Seow; Atanassov, Plamen

    2015-06-16

    In this study, the influence of two quinones (1,2- and 1,4-benzoquinone) on the operation and mechanism of electron transfer in PQQ-sGDH anodes has been determined. Benzoquinones were experimentally explored as mediators present in the electrolyte. The electrochemical performance of the PQQ–sGDH anodes with and without the mediators was examined and for the first time molecular docking simulations were used to gain a fundamental understanding to explain the role of the mediator molecules in the design and operation of the enzymatic electrodes. It was proposed that the higher performance of the PQQ–sGDH anodes in the presence of 1,2- and 1,4-benzoquinones introducedmore » in the solution is due to the shorter distance between these molecules and PQQ in the enzymatic molecule. It was also hypothesized that when 1,4-benzoquinone is adsorbed on a carbon support, it would play the dual role of a mediator and an orienting agent. At the same time, when 1,2-benzoquinone and ubiquinone are adsorbed on the electrode surface, the enzyme would transfer the electrons directly to the support, and these molecules would primarily play the role of an orienting agent.« less

  4. The Mechanism of the Formaldehyde Clock Reaction.

    ERIC Educational Resources Information Center

    Burnett, M. G.

    1982-01-01

    Provides background information and problems with the formaldehyde clock reaction, including comparisons of experimental clock times reported in the literature and conditions for the reliable use of the formaldehyde clock based on a method discussed. (JN)

  5. Formaldehyde Stress Responses in Bacterial Pathogens

    PubMed Central

    Chen, Nathan H.; Djoko, Karrera Y.; Veyrier, Frédéric J.; McEwan, Alastair G.

    2016-01-01

    Formaldehyde is the simplest of all aldehydes and is highly cytotoxic. Its use and associated dangers from environmental exposure have been well documented. Detoxification systems for formaldehyde are found throughout the biological world and they are especially important in methylotrophic bacteria, which generate this compound as part of their metabolism of methanol. Formaldehyde metabolizing systems can be divided into those dependent upon pterin cofactors, sugar phosphates and those dependent upon glutathione. The more prevalent thiol-dependent formaldehyde detoxification system is found in many bacterial pathogens, almost all of which do not metabolize methane or methanol. This review describes the endogenous and exogenous sources of formaldehyde, its toxic effects and mechanisms of detoxification. The methods of formaldehyde sensing are also described with a focus on the formaldehyde responsive transcription factors HxlR, FrmR, and NmlR. Finally, the physiological relevance of detoxification systems for formaldehyde in bacterial pathogens is discussed. PMID:26973631

  6. Formaldehyde Stress Responses in Bacterial Pathogens.

    PubMed

    Chen, Nathan H; Djoko, Karrera Y; Veyrier, Frédéric J; McEwan, Alastair G

    2016-01-01

    Formaldehyde is the simplest of all aldehydes and is highly cytotoxic. Its use and associated dangers from environmental exposure have been well documented. Detoxification systems for formaldehyde are found throughout the biological world and they are especially important in methylotrophic bacteria, which generate this compound as part of their metabolism of methanol. Formaldehyde metabolizing systems can be divided into those dependent upon pterin cofactors, sugar phosphates and those dependent upon glutathione. The more prevalent thiol-dependent formaldehyde detoxification system is found in many bacterial pathogens, almost all of which do not metabolize methane or methanol. This review describes the endogenous and exogenous sources of formaldehyde, its toxic effects and mechanisms of detoxification. The methods of formaldehyde sensing are also described with a focus on the formaldehyde responsive transcription factors HxlR, FrmR, and NmlR. Finally, the physiological relevance of detoxification systems for formaldehyde in bacterial pathogens is discussed. PMID:26973631

  7. A Short Review on Photocatalytic Degradation of Formaldehyde.

    PubMed

    Tasbihi, Minoo; Bendyna, Joanna K; Notten, Peter H L; Hintzen, H T

    2015-09-01

    Nowadays, it is a great challenge to eliminate toxic and harmful organic pollutants from air and water. This paper reviews the role of TiO2 as a photocatalyst, light source and photoreactor in the particular case of removal of formaldehyde using the photocatalytic reaction by titanium dioxide (TiO2) in aqueous and gaseous systems. The reaction mechanisms of the photocatalytic oxidation of gaseous formaldehyde are given. We also present a detailed review of published articles on photocatalytic degradation of formaldehyde by modified titanium dioxide doped with foreign species such as metal and non-metal components. We point out the most prospective developments of the photocatalyst compositions for the future potential commercial applications. PMID:26716192

  8. XoxF encoding an alternative methanol dehydrogenase is widespread in coastal marine environments.

    PubMed

    Taubert, Martin; Grob, Carolina; Howat, Alexandra M; Burns, Oliver J; Dixon, Joanna L; Chen, Yin; Murrell, J Colin

    2015-10-01

    The xoxF gene, encoding a pyrroloquinoline quinone-dependent methanol dehydrogenase, is found in all known proteobacterial methylotrophs. In several newly discovered methylotrophs, XoxF is the active methanol dehydrogenase, catalysing the oxidation of methanol to formaldehyde. Apart from that, its potential role in methylotrophy and carbon cycling is unknown. So far, the diversity of xoxF in the environment has received little attention. We designed PCR primer sets targeting clades of the xoxF gene, and used 454 pyrosequencing of PCR amplicons obtained from the DNA of four coastal marine environments for a unique assessment of the diversity of xoxF in these habitats. Phylogenetic analysis of the data obtained revealed a high diversity of xoxF genes from two of the investigated clades, and substantial differences in sequence composition between environments. Sequences were classified as being related to a wide range of both methylotrophs and non-methylotrophs from Alphaproteobacteria, Betaproteobacteria and Gammaproteobacteria. The most prominent sequences detected were related to the family Rhodobacteraceae, the genus Methylotenera and the OM43 clade of Methylophilales, and are thus related to organisms that employ XoxF for methanol oxidation. Furthermore, our analyses revealed a high degree of so far undescribed sequences, suggesting a high number of unknown bacterial species in these habitats. PMID:25943904

  9. Formaldehyde exposures from tobacco smoke: a review.

    PubMed Central

    Godish, T

    1989-01-01

    Reports of formaldehyde levels in mainstream, sidestream, and environmental tobacco smoke from nine studies are reviewed. Considerable disparity exists between formaldehyde production rates determined from mainstream-sidestream studies and those reporting levels in environmental tobacco smoke. Tobacco smoke does not appear to increase vapor-phase formaldehyde levels significantly in indoor environments, but formaldehyde exposure in mainstream smoke may pose a risk of upper respiratory system cancer and increase the risk of cancer in smokers. PMID:2665532

  10. Formaldehyde reactions in dark clouds

    NASA Technical Reports Server (NTRS)

    Sen, A. D.; Anicich, V. G.; Federman, S. R.

    1992-01-01

    The low-pressure reactions of formaldehyde (H2CO) with D(+), D2(+), D3(+), and He(+) are studied by the ion-cyclotron resonance technique. These reactions are potential loss processes for formaldehyde in cores of dark interstellar clouds. The deuterated reactants represent direct analogs for protons. Rate coefficients and branching ratios of product channels have been measured. Charge transfer is observed to be the dominant reaction of H2CO with D(+), D2(+), and He(+) ions. Only the D3(+) reaction exhibits a proton-transfer channel. All reactions proceed at rate coefficients near the collision limit. Proton-deuteron exchange reactions are found to be inefficient processes in the formaldehyde system.

  11. In vivo roles of alcohol dehydrogenase (ADH), catalase and the microsomal ethanol oxidizing system (MEOS) in deermice

    SciTech Connect

    Takagi, T.; Alderman, J.; Lieber, C.S.

    1985-01-01

    The relative importance of ADH and MEOS for ethanol oxidation in the liver has yet to be elucidated. The discovery of a strain of deermice genetically lacking ADH (ADH-) which can consume ethanol at greater than 50% of the rates seen in deermice having ADH (ADH+) suggested a significant role for non-ADH pathways in vivo. To quantitate contributions of the various pathways, the authors examined first the ethanol oxidation rates with or without 4-methylpyrazole in isolated deermice hepatocytes. 4-Methylpyrazole significantly reduced the ethanol oxidation in both ADH+ and ADH- hepatocytes. The reduction seen in ADH- cells can be applied to correct for the effect of 4-methylpyrazole on non-ADH pathways of ADH+ deermouse hepatocytes. After correction, non-ADH pathways were found to contribute 28% of ethanol metabolism at 10 mM and 52% at 50 mM. When using a different approach namely measurement of the isotope effect, MEOS was calculated to account for 35% at low and about 70% at high blood ethanol concentrations. Thus, they found that two different complementary approaches yielded similar results, namely that non-ADH pathways play a significant role in ethanol oxidation even in the presence of ADH.

  12. Home Is Where the Formaldehyde Is.

    ERIC Educational Resources Information Center

    Godish, Thad

    1983-01-01

    Discusses indoor air pollution in general and formaldehyde in particular, citing major sources of formaldehyde in home building materials and home furnishings. Also describes a laboratory procedure necessary to test for formaldehyde levels in the air and in materials. Includes list of equipment required. (JM)

  13. Alcohol Dehydrogenase Protects against Endoplasmic Reticulum Stress-Induced Myocardial Contractile Dysfunction via Attenuation of Oxidative Stress and Autophagy: Role of PTEN-Akt-mTOR Signaling

    PubMed Central

    Pang, Jiaojiao; Fuller, Nathan D.; Hu, Nan; Barton, Linzi A.; Henion, Jeremy M.; Guo, Rui; Chen, Yuguo; Ren, Jun

    2016-01-01

    Background The endoplasmic reticulum (ER) plays an essential role in ensuring proper folding of the newly synthesized proteins. Aberrant ER homeostasis triggers ER stress and development of cardiovascular diseases. ADH is involved in catalyzing ethanol to acetaldehyde although its role in cardiovascular diseases other than ethanol metabolism still remains elusive. This study was designed to examine the impact of ADH on ER stress-induced cardiac anomalies and underlying mechanisms involved using cardiac-specific overexpression of alcohol dehydrogenase (ADH). Methods ADH and wild-type FVB mice were subjected to the ER stress inducer tunicamycin (1 mg/kg, i.p., for 48 hrs). Myocardial mechanical and intracellular Ca2+ properties, ER stress, autophagy and associated cell signaling molecules were evaluated. Results ER stress compromised cardiac contractile function (evidenced as reduced fractional shortening, peak shortening, maximal velocity of shortening/relengthening, prolonged relengthening duration and impaired intracellular Ca2+ homeostasis), oxidative stress and upregulated autophagy (increased LC3B, Atg5, Atg7 and p62), along with dephosphorylation of PTEN, Akt and mTOR, all of which were attenuated by ADH. In vitro study revealed that ER stress-induced cardiomyocyte anomaly was abrogated by ADH overexpression or autophagy inhibition using 3-MA. Interestingly, the beneficial effect of ADH was obliterated by autophagy induction, inhibition of Akt and mTOR. ER stress also promoted phosphorylation of the stress signaling ERK and JNK, the effect of which was unaffected by ADH transgene. Conclusions Taken together, these findings suggested that ADH protects against ER stress-induced cardiac anomalies possibly via attenuation of oxidative stress and PTEN/Akt/mTOR pathway-regulated autophagy. PMID:26807981

  14. The prognostic role of lactate dehydrogenase serum levels in patients with hepatocellular carcinoma who are treated with sorafenib: the influence of liver fibrosis

    PubMed Central

    Yada, Masayoshi; Miyazaki, Masayuki; Motomura, Kenta; Masumoto, Akihide; Nakamuta, Makoto; Kohjima, Motoyuki; Sugimoto, Rie; Aratake, Yoshifusa; Higashi, Nobuhiko; Morizono, Shusuke; Takao, Shinichiro; Yamashita, Naoki; Satoh, Takeaki; Yamashita, Shinsaku; Kuniyoshi, Masami

    2016-01-01

    Background Serum lactate dehydrogenase (LDH) levels could be a prognostic factor for sorafenib-treated patients with several types of solid tumor because it reflects hypoxic circumstances in aggressive tumors. For hepatocellular carcinoma (HCC), however, the prognostic role of LDH has been controversial. Liver fibrosis can potentially cause hypoxia in the liver, which has not been previously studied in the patients with advanced HCC. Thus, we aimed to analyze the prognostic role of LDH based on the degree of fibrosis. Methods Eighty-nine consecutive patients with HCC (Child-Pugh class A) who were treated using sorafenib were enrolled into this study. Pretreatment characteristics and changes in hepatic functional tests based on early response to sorafenib and serum LDH levels were analyzed. The degree of fibrosis was estimated using the aspartate aminotransferase (AST) to platelet ratio index (APRI), and the tumor response was evaluated after 3 months of sorafenib treatment. Results Overall, five patients discontinued sorafenib within 4 weeks. For the other 84 patients, those with progressive disease (PD) had significantly high pretreatment LDH levels, which correlated with the APRI score but not with the tumor stage. Multivariate logistic analysis revealed that older age and lower pretreatment LDH levels were independent prognostic factors for a better response to sorafenib. In patients who discontinued sorafenib early, three experienced acute liver failure accompanied with an increase in serum LDH. Conclusions We demonstrated that baseline serum LDH levels in HCC patients were affected by liver fibrosis but not by the tumor stage, and these LDH levels could be a marker for early response to sorafenib. A marked increase in serum LDH levels during sorafenib administration might also indicate subsequent acute liver failure. Close observation of serum LDH levels before and during sorafenib treatment could be useful in managing treatment of patients receiving this

  15. Role of Medium- and Short-Chain L-3-Hydroxyacyl-CoA Dehydrogenase in the Regulation of Body Weight and Thermogenesis

    PubMed Central

    Schulz, Nadja; Himmelbauer, Heinz; Rath, Michaela; van Weeghel, Michel; Houten, Sander; Kulik, Wim; Suhre, Karsten; Scherneck, Stephan; Vogel, Heike; Kluge, Reinhart; Wiedmer, Petra; Joost, Hans-Georg

    2011-01-01

    Dysregulation of fatty acid oxidation plays a pivotal role in the pathophysiology of obesity and insulin resistance. Medium- and short-chain-3-hydroxyacyl-coenzyme A (CoA) dehydrogenase (SCHAD) (gene name, hadh) catalyze the third reaction of the mitochondrial β-oxidation cascade, the oxidation of 3-hydroxyacyl-CoA to 3-ketoacyl-CoA, for medium- and short-chain fatty acids. We identified hadh as a putative obesity gene by comparison of two genome-wide scans, a quantitative trait locus analysis previously performed in the polygenic obese New Zealand obese mouse and an earlier described small interfering RNA-mediated mutagenesis in Caenorhabditis elegans. In the present study, we show that mice lacking SCHAD (hadh−/−) displayed a lower body weight and a reduced fat mass in comparison with hadh+/+ mice under high-fat diet conditions, presumably due to an impaired fuel efficiency, the loss of acylcarnitines via the urine, and increased body temperature. Food intake, total energy expenditure, and locomotor activity were not altered in knockout mice. Hadh−/− mice exhibited normal fat tolerance at 20 C. However, during cold exposure, knockout mice were unable to clear triglycerides from the plasma and to maintain their normal body temperature, indicating that SCHAD plays an important role in adaptive thermogenesis. Blood glucose concentrations in the fasted and postprandial state were significantly lower in hadh−/− mice, whereas insulin levels were elevated. Accordingly, insulin secretion in response to glucose and glucose plus palmitate was elevated in isolated islets of knockout mice. Therefore, our data indicate that SCHAD is involved in thermogenesis, in the maintenance of body weight, and in the regulation of nutrient-stimulated insulin secretion. PMID:21990309

  16. [Studies on the remote measurement of the emission of formaldehyde by mobile differential optical absorption spectroscopy].

    PubMed

    Wu, Feng-Cheng; Xie, Pin-Hua; Li, Ang; Si, Fu-Qi; Dou, Ke; Liu, Yu; Xu, Jin; Wang, Jie

    2011-11-01

    Formaldehyde (HCHO) is the most abundant carbonyl compounds that play an important role in atmospheric chemistry and photochemical reactions. Formaldehyde is an important indicator of atmospheric reactivity and urban atmospheric aerosol precursors. In the present paper, the emission of formaldehyde from chemical area was measured using the mobile differential optical absorption spectroscopy (DOAS). This instrument uses the zenith scattered sunlight as the light source with successful sampling in the area loop. Vertical column density was retrieved by this system, combined with the meteorological wind field and car speed information, the emission of formaldehyde in the area was estimated. The authors carried out the measuring experiment in one chemical plant in Beijing using this technology. The result showed that the average value of the flux of formaldehyde in this area was 605 kg x h(-1) during the measuring period. PMID:22242505

  17. Photoionization of methanol and formaldehyde

    NASA Technical Reports Server (NTRS)

    Warneck, P.

    1971-01-01

    Photoions produced in methanol and formaldehyde by radiation in the spectral region 450-1150 A were analyzed mass spectrometrically, and their relative yields were determined as a function of wavelength. First ionization potentials were determined, and the ion yield curves were interpreted in terms of ionization processes in conjunction with other data. Fragment ions were detected on mass numbers of 31, 30, 29, 15, and 14 for methanol, and 29, 2, and 1 for formaldehyde. The associated appearance potentials were determined and were used to calculate heats of formation of the ions CH2OH(+) and HCO(+), and the radicals CH3, CH2, and HCO.

  18. Woodstoves, formaldehyde, and respiratory disease

    SciTech Connect

    Tuthill, R.W.

    1984-12-01

    Telephone interviews were completed in Western Massachusetts in April 1983 for 399 households (91.5 percent) in a random sample of households with elementary school children. Woodstoves were used in 64.7 percent of the homes, but such use was not associated with acute respiratory illness. However, formaldehyde exposure was significantly related, with a risk ratio of 2.4 (95 percent confidence interval 1.7-3.4). New construction/remodeling and new upholstered furniture had additive effects. Neither woodstove use nor formaldehyde exposure were significantly associated with asthma, chronic bronchitis, or allergies.

  19. The role of aldehyde/alcohol dehydrogenase (AdhE) in ethanol production from glycerol by Klebsiella pneumoniae.

    PubMed

    Oh, Baek-Rock; Hong, Won-Kyung; Heo, Sun-Yeon; Joe, Min-ho; Seo, Jeong-Woo; Kim, Chul Ho

    2013-02-01

    Transcriptome analysis of a K. pneumoniae GEM167 mutant strain derived by irradiation with gamma rays, which exhibited high-level production of ethanol from glycerol, showed that the mutant expressed AdhE at a high level. Ethanol production decreased significantly, from 8.8 to 0.5 g l(-1), when an adhE-deficient derivative of that strain was grown on glycerol. Bacterial growth was also reduced under such conditions, showing that AdhE plays a critical role in maintenance of redox balance by catalyzing ethanol production. Overexpression of AdhE enhanced ethanol production, from pure or crude glycerol, to a maximal level of 31.9 g l(-1) under fed-batch fermentation conditions; this is the highest level of ethanol production from glycerol reported to date. PMID:23296976

  20. Role of convection in redistributing formaldehyde to the upper troposphere over North America and the North Atlantic during the summer 2004 INTEX campaign

    NASA Astrophysics Data System (ADS)

    Fried, Alan; Olson, Jennifer R.; Walega, James G.; Crawford, Jim H.; Chen, Gao; Weibring, Petter; Richter, Dirk; Roller, Chad; Tittel, Frank; Porter, Michael; Fuelberg, Henry; Halland, Jeremy; Bertram, Timothy H.; Cohen, Ronald C.; Pickering, Kenneth; Heikes, Brian G.; Snow, Julie A.; Shen, Haiwei; O'Sullivan, Daniel W.; Brune, William H.; Ren, Xinrong; Blake, Donald R.; Blake, Nicola; Sachse, Glen; Diskin, Glenn S.; Podolske, James; Vay, Stephanie A.; Shetter, Richard E.; Hall, Samuel R.; Anderson, Bruce E.; Thornhill, Lee; Clarke, Antony D.; McNaughton, Cameron S.; Singh, Hanwant B.; Avery, Melody A.; Huey, Gregory; Kim, Saewung; Millet, Dylan B.

    2008-09-01

    Measurements of formaldehyde (CH2O) from a tunable diode laser absorption spectrometer (TDLAS) were acquired onboard the NASA DC-8 aircraft during the summer 2004 INTEX-NA campaign to test our understanding of convection and CH2O production mechanisms in the upper troposphere (UT, 6-12 km) over continental North America and the North Atlantic Ocean. The present study utilizes these TDLAS measurements and results from a box model to (1) establish sets of conditions by which to distinguish "background" UT CH2O levels from those perturbed by convection and other causes; (2) quantify the CH2O precursor budgets for both air mass types; (3) quantify the fraction of time that the UT CH2O measurements over North America and North Atlantic are perturbed during the summer of 2004; (4) provide estimates for the fraction of time that such perturbed CH2O levels are caused by direct convection of boundary layer CH2O and/or convection of CH2O precursors; (5) assess the ability of box models to reproduce the CH2O measurements; and (6) examine CH2O and HO2 relationships in the presence of enhanced NO. Multiple tracers were used to arrive at a set of UT CH2O background and perturbed air mass periods, and 46% of the TDLAS measurements fell within the latter category. In general, production of CH2O from CH4 was found to be the dominant source term, even in perturbed air masses. This was followed by production from methyl hydroperoxide, methanol, PAN-type compounds, and ketones, in descending order of their contribution. At least 70% to 73% of the elevated UT observations were caused by enhanced production from CH2O precursors rather than direct transport of CH2O from the boundary layer. In the presence of elevated NO, there was a definite trend in the CH2O measurement-model discrepancy, and this was highly correlated with HO2 measurement-model discrepancies in the UT.

  1. Immobilized formaldehyde-metabolizing enzymes from Hansenula polymorpha for removal and control of airborne formaldehyde.

    PubMed

    Sigawi, Sasi; Smutok, Oleh; Demkiv, Olha; Zakalska, Oksana; Gayda, Galina; Nitzan, Yeshayahu; Nisnevitch, Marina; Gonchar, Mykhaylo

    2011-05-20

    Formaldehyde (FA)-containing indoor air has a negative effect on human health and should be removed by intensive ventilation or by catalytic conversion to non-toxic products. FA can be oxidized by alcohol oxidase (AOX) taking part in methanol metabolism of methylotrophic yeasts. In the present work, AOX isolated from a Hansenula polymorpha C-105 mutant (gcr1 catX) overproducing this enzyme in glucose medium, was tested for its ability to oxidize airborne FA. A continuous fluidized bed bioreactor (FBBR) was designed to enable an effective bioconversion of airborne FA by AOX or by permeabilized mutant H. polymorpha C-105 cells immobilized in calcium alginate beads. The immobilized AOX having a specific activity of 6-8 U mg⁻¹ protein was shown to preserve 85-90% of the initial activity. The catalytic parameters of the immobilized enzyme were practically the same as for the free enzyme (k(cat)/K(m) was 2.35×10³ M⁻¹ s⁻¹ vs 2.89×10³ M⁻¹ s⁻¹, respectively). The results showed that upon bubbling of air containing from 0.3 up to 18.5 ppm FA through immobilized AOX in the range of 1.3-26.6 U g⁻¹ of the gel resulted in essential decrease of FA concentration in the outlet gas phase (less than 0.02-0.03 ppm, i.e. 10-fold less than the threshold limit value). It was also demonstrated that a FBBR with immobilized permeabilized C-105 cells provided more than 90% elimination of airborne FA. The process was monitored by a specially constructed enzymatic amperometric biosensor based on FA oxidation by NAD+ and glutathione-dependent formaldehyde dehydrogenase from the recombinant H. polymorpha Tf 11-6 strain. PMID:21504769

  2. Embryo toxicity and teratogenicity of formaldehyde.

    PubMed

    Thrasher, J D; Kilburn, K H

    2001-01-01

    C-14 formaldehyde crosses the placenta and enters fetal tissues. The incorporated radioactivity is higher in fetal organs (i.e., brain and liver) than in maternal tissues. The incorporation mechanism has not been studied fully, but formaldehyde enters the single-carbon cycle and is incorporated as a methyl group into nucleic acids and proteins. Also, formaldehyde reacts chemically with organic compounds (e.g., deoxyribonucleic acid, nucleosides, nucleotides, proteins, amino acids) by addition and condensation reactions, thus forming adducts and deoxyribonucleic acid-protein crosslinks. The following questions must be addressed: What adducts (e.g., N-methyl amino acids) are formed in the blood following formaldehyde inhalation? What role do N-methyl-amino adducts play in alkylation of nuclear and mitochondrial deoxyribonucleic acid, as well as mitochondrial peroxidation? The fact that the free formaldehyde pool in blood is not affected following exposure to the chemical does not mean that formaldehyde is not involved in altering cell and deoxyribonucleic acid characteristics beyond the nasal cavity. The teratogenic effect of formaldehyde in the English literature has been sought, beginning on the 6th day of pregnancy (i.e., rodents) (Saillenfait AM, et al. Food Chem Toxicol 1989, pp 545-48; Martin WJ. Reprod Toxicol 1990, pp 237-39; Ulsamer AG, et al. Hazard Assessment of Chemicals; Academic Press, 1984, pp 337-400; and U.S. Department of Health and Human Services. Toxicological Profile of Formaldehyde; ATSDR, 1999 [references 1-4, respectively, herein]). The exposure regimen is critical and may account for the differences in outcomes. Pregnant rats were exposed (a) prior to mating, (b) during mating, (c) or during the entire gestation period. These regimens (a) increased embryo mortality; (b) increased fetal anomalies (i.e., cryptochordism and aberrant ossification centers); (c) decreased concentrations of ascorbic acid; and (d) caused abnormalities in enzymes of

  3. Endogenous Formaldehyde Is a Hematopoietic Stem Cell Genotoxin and Metabolic Carcinogen

    PubMed Central

    Pontel, Lucas B.; Rosado, Ivan V.; Burgos-Barragan, Guillermo; Garaycoechea, Juan I.; Yu, Rui; Arends, Mark J.; Chandrasekaran, Gayathri; Broecker, Verena; Wei, Wei; Liu, Limin; Swenberg, James A.; Crossan, Gerry P.; Patel, Ketan J.

    2015-01-01

    Summary Endogenous formaldehyde is produced by numerous biochemical pathways fundamental to life, and it can crosslink both DNA and proteins. However, the consequences of its accumulation are unclear. Here we show that endogenous formaldehyde is removed by the enzyme alcohol dehydrogenase 5 (ADH5/GSNOR), and Adh5−/− mice therefore accumulate formaldehyde adducts in DNA. The repair of this damage is mediated by FANCD2, a DNA crosslink repair protein. Adh5−/−Fancd2−/− mice reveal an essential requirement for these protection mechanisms in hematopoietic stem cells (HSCs), leading to their depletion and precipitating bone marrow failure. More widespread formaldehyde-induced DNA damage also causes karyomegaly and dysfunction of hepatocytes and nephrons. Bone marrow transplantation not only rescued hematopoiesis but, surprisingly, also preserved nephron function. Nevertheless, all of these animals eventually developed fatal malignancies. Formaldehyde is therefore an important source of endogenous DNA damage that is counteracted in mammals by a conserved protection mechanism. PMID:26412304

  4. Formaldehyde in Insulation: Villain or Innocent Bystander?

    PubMed Central

    Lees, R. E. M.

    1983-01-01

    When urea formaldehyde foam insulation (UFFI) deteriorates, it produces an off-gas mixture whose major constituent is formaldehyde. Most investigative studies of UFFI have concentrated on formaldehyde. Health concerns fall into three groups: irritant characteristics, allergenic capabilities and potential carcinogenicity. Except for the first of these, formaldehyde's hazard potential is not clear. The extent to which formaldehyde may be responsible for UFFI's evil reputation is explored in this paper but the degree to which either substance is a real threat to health still appears to open to debate. PMID:21283296

  5. Controlling formaldehyde emissions with boiler ash.

    PubMed

    Cowan, Jennifer; Abu-Daabes, Malyuba; Banerjee, Sujit

    2005-07-01

    Fluidized wood ash reduces formaldehyde in air from about 20 to <1 ppmv. Methanol is removed to a much lower extent. The efficiency of formaldehyde reduction increases with increasing moisture content of the ash. Sorption of formaldehyde to ash can be substantially accounted for by partitioning to the water contained in the ash followed by rate-controlling binding to the ash solids. Adsorption occurs at temperatures of up to 165 degrees C; oxidation predominates thereafter. It is proposed that formaldehyde could be stripped from an air stream in a fluidized bed containing ash, which could then be returned to a boiler to incinerate the formaldehyde. PMID:16053116

  6. Formaldehyde monitor for automobile exhausts

    NASA Technical Reports Server (NTRS)

    Easley, W. C.

    1973-01-01

    Device makes use of microwave spectral absorption in low-Q resonant Stark cell, and indications are that ultimate sensitivity of instrument is within 100 parts per billion of formaldehyde. Microwave source is very small and requires only six-volt dc bias for operation. Coarse tuning is accomplished mechanically and fine tuning by adjusting dc-bias voltage.

  7. Transgenic male mice expressing human hydroxysteroid dehydrogenase 2 indicate a role for the enzyme independent of its action on sex steroids.

    PubMed

    Zhongyi, Shen; Rantakari, Pia; Lamminen, Tarja; Toppari, Jorma; Poutanen, Matti

    2007-08-01

    Hydroxysteroid (17beta) dehydrogenase 2 (HSD17B2) has been shown to inactivate both estrogens and androgens and activate 20alpha-hydroxyprogesterone to progesterone. In the present study, we generated transgenic (TG) mice ubiquitously expressing human HSD17B2. The TG mice produced showed growth retardation and delayed eye opening at the postnatal age. Disrupted spermatogenesis was evident in the presence of normal serum and intratesticular testosterone, progesterone, and normal circulating LH concentrations. A proper androgen action in the target tissues was confirmed by normal histological appearance of the prostate and epididymis. Furthermore, quantitative RT-PCR analysis indicated only a slight decrease in androgen-dependent gene expression in the prostate. The disrupted spermatogenesis was not associated with increased germ cell apoptosis as analyzed by caspase-3 activation. However, it resulted in infertility in the HSD17B2 TG males after the age of 3 months, and at the age of 6 months the seminiferous tubules showed a Sertoli cell-only phenotype. The data indicate that the growth retardation and disrupted spermatogenesis are not due to a lack of proper estrogen or androgen action. Interestingly, the testicular phenotype and some of the other phenotypic changes described are typically observed in mice with reduced action of retinoic acid signaling. This, together with the rescue of the testis phenotype by a synthetic retinoic acid receptor agonist (4-[(E)-2-(5, 6, 7, 8-tetrahydro-5, 5, 8, 8-tetramethyl-2-naphthalenyl)-1-propenyl] benzoic acid), suggests a role for HSD17B2 in the action of retinoids, in addition to its oxidative HSD17B activity on sex steroids. PMID:17510238

  8. In vitro oxidative metabolism of 6-mercaptopurine in human liver: insights into the role of the molybdoflavoenzymes aldehyde oxidase, xanthine oxidase, and xanthine dehydrogenase.

    PubMed

    Choughule, Kanika V; Barnaba, Carlo; Joswig-Jones, Carolyn A; Jones, Jeffrey P

    2014-08-01

    Anticancer agent 6-mercaptopurine (6MP) has been in use since 1953 for the treatment of childhood acute lymphoblastic leukemia (ALL) and inflammatory bowel disease. Despite being available for 60 years, several aspects of 6MP drug metabolism and pharmacokinetics in humans are unknown. Molybdoflavoenzymes such as aldehyde oxidase (AO) and xanthine oxidase (XO) have previously been implicated in the metabolism of this drug. In this study, we investigated the in vitro metabolism of 6MP to 6-thiouric acid (6TUA) in pooled human liver cytosol. We discovered that 6MP is metabolized to 6TUA through sequential metabolism via the 6-thioxanthine (6TX) intermediate. The role of human AO and XO in the metabolism of 6MP was established using the specific inhibitors raloxifene and febuxostat. Both AO and XO were involved in the metabolism of the 6TX intermediate, whereas only XO was responsible for the conversion of 6TX to 6TUA. These findings were further confirmed using purified human AO and Escherichia coli lysate containing expressed recombinant human XO. Xanthine dehydrogenase (XDH), which belongs to the family of xanthine oxidoreductases and preferentially reduces nicotinamide adenine dinucleotide (NAD(+)), was shown to contribute to the overall production of the 6TX intermediate as well as the final product 6TUA in the presence of NAD(+) in human liver cytosol. In conclusion, we present evidence that three enzymes, AO, XO, and XDH, contribute to the production of 6TX intermediate, whereas only XO and XDH are involved in the conversion of 6TX to 6TUA in pooled HLC. PMID:24824603

  9. Biological Roles of Hydroxysteroid (11-Beta) Dehydrogenase 1 (HSD11B1), HSD11B2, and Glucocorticoid Receptor (NR3C1) in Sheep Conceptus Elongation.

    PubMed

    Brooks, Kelsey; Burns, Gregory; Spencer, Thomas E

    2015-08-01

    In sheep, the elongating conceptus synthesizes and secretes interferon tau (IFNT) as well as prostaglandins (PGs) and cortisol. The enzymes, hydroxysteroid (11-beta) dehydrogenase 1 (HSD11B1) and HSD11B2 interconvert cortisone and cortisol. In sheep, HSD11B1 is expressed and active in the conceptus trophectoderm as well as in the endometrial luminal epithelia; in contrast, HSD11B2 expression is most abundant in conceptus trophectoderm. Cortisol is a biologically active glucocorticoid and ligand for the glucocorticoid receptor (NR3C1 or GR) and mineralocorticoid receptor (NR3C2 or MR). Expression of MR is not detectable in either the ovine endometrium or conceptus during early pregnancy. In tissues that do not express MR, HSD11B2 protects cells from the growth-inhibiting and/or proapoptotic effects of cortisol, particularly during embryonic development. In study one, an in utero loss-of-function analysis of HSD11B1 and HSD11B2 was conducted in the conceptus trophectoderm using morpholino antisense oligonucleotides (MAOs) that inhibit mRNA translation. Elongating, filamentous conceptuses were recovered on Day 14 from ewes infused with control morpholino or HSD11B2 MAO. In contrast, HSD11B1 MAO resulted in severely growth-retarded conceptuses or conceptus fragments with apoptotic trophectoderm. In study two, clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 genome editing was used to determine the role of GR in conceptus elongation and development. Elongating, filamentous-type conceptuses (12-14 cm in length) were recovered from ewes gestating control embryos (n = 7/7) and gestating GR-edited embryos (n = 6/7). These results support the idea that the effects of HSD11B1-derived cortisol on conceptus elongation are indirectly mediated by the endometrium and are not directly mediated through GR in the trophectoderm. PMID:26085523

  10. Expression profiles of cortisol-inactivating enzyme, 11β-hydroxysteroid dehydrogenase-2, in human epidermal tumors and its role in keratinocyte proliferation.

    PubMed

    Terao, Mika; Itoi, Saori; Murota, Hiroyuki; Katayama, Ichiro

    2013-02-01

    The enzyme 11β-hydroxysteroid dehydrogenase (11β-HSD) catalyzes the interconversion between hormonally active cortisol and inactive cortisone within cells. There are two isozymes: 11β-HSD1 activates cortisol from cortisone and 11β-HSD2 inactivates cortisol to cortisone. 11β-HSD1 was recently discovered in skin, and we subsequently found that the enzyme negatively regulates keratinocyte proliferation. We verified 11β-HSD1 and 11β-HSD2 expression in benign and malignant skin tumors and investigated the role of 11β-HSD in skin tumor pathogenesis. Randomly selected formalin-fixed sections of skin lesions of seborrheic keratosis (SK), squamous cell carcinoma (SCC), and basal cell carcinoma (BCC) were stained with 11β-HSD1 and 11β-HSD2 antibodies, and 11β-HSD expression was also evaluated in murine epidermis in which hyperproliferation was induced by 12-O-tetradecanoylphorbol-13 acetate (TPA). We observed that 11β-HSD1 expression was decreased in all SK, SCC, and BCC lesions compared with unaffected skin. Conversely, 11β-HSD2 expression was increased in SK and BCC but not in SCC. Overexpression of 11β-HSD2 in keratinocytes increased cell proliferation. In the murine model, 11β-HSD1 expression was decreased in TPA-treated hyperproliferative skin. Our findings suggest that 11β-HSD1 expression is decreased in keratinocyte proliferative conditions, and 11β-HSD2 expression is increased in basal cell proliferating conditions, such as BCC and SK. Assessing 11β-HSD1 and 11β-HSD2 expression could be a useful tool for diagnosing and characterizing skin tumors. PMID:23362866

  11. Glyceraldehyde-3-Phosphate Dehydrogenase (GAPDH) Protein-Protein Interaction Inhibitor Reveals a Non-catalytic Role for GAPDH Oligomerization in Cell Death.

    PubMed

    Qvit, Nir; Joshi, Amit U; Cunningham, Anna D; Ferreira, Julio C B; Mochly-Rosen, Daria

    2016-06-24

    Glyceraldehyde-3-phosphate dehydrogenase (GAPDH), an important glycolytic enzyme, has a non-catalytic (thus a non-canonical) role in inducing mitochondrial elimination under oxidative stress. We recently demonstrated that phosphorylation of GAPDH by δ protein kinase C (δPKC) inhibits this GAPDH-dependent mitochondrial elimination. δPKC phosphorylation of GAPDH correlates with increased cell injury following oxidative stress, suggesting that inhibiting GAPDH phosphorylation should decrease cell injury. Using rational design, we identified pseudo-GAPDH (ψGAPDH) peptide, an inhibitor of δPKC-mediated GAPDH phosphorylation that does not inhibit the phosphorylation of other δPKC substrates. Unexpectedly, ψGAPDH decreased mitochondrial elimination and increased cardiac damage in an animal model of heart attack. Either treatment with ψGAPDH or direct phosphorylation of GAPDH by δPKC decreased GAPDH tetramerization, which corresponded to reduced GAPDH glycolytic activity in vitro and ex vivo Taken together, our study identified the potential mechanism by which oxidative stress inhibits the protective GAPDH-mediated elimination of damaged mitochondria. Our study also identified a pharmacological tool, ψGAPDH peptide, with interesting properties. ψGAPDH peptide is an inhibitor of the interaction between δPKC and GAPDH and of the resulting phosphorylation of GAPDH by δPKC. ψGAPDH peptide is also an inhibitor of GAPDH oligomerization and thus an inhibitor of GAPDH glycolytic activity. Finally, we found that ψGAPDH peptide is an inhibitor of the elimination of damaged mitochondria. We discuss how this unique property of increasing cell damage following oxidative stress suggests a potential use for ψGAPDH peptide-based therapy. PMID:27129213

  12. Oxidation of C1 compounds by particulate fractions from Methylococcus capsulatus: properties of methanol oxidase and methanol dehydrogenase.

    PubMed Central

    Wadzinski, A M; Ribbons, D W

    1975-01-01

    Methanol (and formaldehyde) oxidizing activities in crude extracts of Methylococcus capsulatus are associated mainly with particulate fractions sedimenting between 3,000 and 40,000 X g. Most of the phenazine methosulfate (PMS)-dependent methanol (and formaldehyde) dehydrogenase activity observed resides in the soluble fraction but represents only 40% of the total (PMS dependent plus independent) activity. Both PMS-dependent methanol dehydrogenase activity and PMS-independent methanol oxidase activity are found in particulate fractions, and the PMS-dependent dehydrogenase is easily solubilized by treatment with certain phospholipases or detergents. The properties of the PMS-dependent dehydrogenase activities in the soluble fraction and that solubilized from the particles suggested that they may be identical proteins. Their pH optima, temperature dependence, thermolabilities, and sensitivities to the presence of specific antisera were indistinguishable. Homogeneous preparations of the enzyme proteins obtained from the soluble fractions of extracts and the particulate fractions solubilized by detergents had similar: (i) electrophoretic mobilities in native and denatured states (subunit size in sodium dodecyl sulfate 62,000 daltons); (ii) molecular radii under native conditions, (iii) visible absorption spectra, lambdamax 350 nm, (iv) kinetic constants for methanol and formaldehyde; (v) substrate specificity; and (vi) immunological characteristics--antisera to each enzyme preparation showed precipitin lines of identity to either of the enzymes. It is suggested that the major site of methanol and formaldehyde oxidation in M. capsulatus occurs on the intracytoplasmic membranes in vivo and is coupled to oxygen reduction. Images PMID:238947

  13. Dye-linked D-amino acid dehydrogenase from the thermophilic bacterium Rhodothermus marinus JCM9785: characteristics and role in trans-4-hydroxy-L-proline catabolism.

    PubMed

    Satomura, Takenori; Ishikura, Masaru; Koyanagi, Takashi; Sakuraba, Haruhiko; Ohshima, Toshihisa; Suye, Shin-ichiro

    2015-05-01

    A gene from the thermophilic Gram-negative bacterium Rhodothermus marinus JCM9785, encoding a dye-linked D-amino acid dehydrogenase homologue, was overexpressed in Escherichia coli, and its product was purified and characterized. The expressed enzyme was a highly thermostable dye-linked D-amino acid dehydrogenase that retained more than 80% of its activity after incubation for 10 min at up to 70 °C. When enzyme-catalyzed dehydrogenation of several D-amino acids was carried out using 2,6-dichloroindophenol as the electron acceptor, D-phenylalanine was the most preferable substrate among the D-amino acids tested. Immediately upstream of the dye-linked D-amino acid dehydrogenase gene (dadh) was a gene encoding a 4-hydroxyproline 2-epimerase homologue (hypE). That gene was successfully expressed in E. coli, and the gene product exhibited strong 4-hydroxyproline 2-epimerase activity. Reverse transcription PCR and quantitative real-time PCR showed that the six genes containing the dadh and hypE genes were arranged in an operon and were required for catabolism of trans-4-hydroxy-L-proline in R. marinus. This is the first description of a dye-linked D-amino acid dehydrogenase (Dye-DADH) with broad substrate specificity involved in trans-4-hydroxy-L-proline catabolism. PMID:25472442

  14. Collisional excitation of interstellar formaldehyde

    NASA Technical Reports Server (NTRS)

    Green, S.; Garrison, B. J.; Lester, W. A., Jr.; Miller, W. H.

    1978-01-01

    Previous calculations for rates of excitation of ortho-H2CO by collisions with He have been extended to higher rotational levels and kinetic temperatures to 80 K. Rates for para-H2CO have also been computed. Pressure-broadening widths for several spectral lines have been obtained from these calculations and are found to agree with recent data within the experimental uncertainty of 10%. Excitation of formaldehyde by collisions with H2 molecules is also discussed.

  15. Microencapsulated fragrances in melamine formaldehyde resins.

    PubMed

    Bône, Stéphane; Vautrin, Claire; Barbesant, Virginie; Truchon, Stéphane; Harrison, Ian; Geffroy, Cédric

    2011-01-01

    The process for making melamine formaldehyde microcapsules containing fragrant oil is well-known. Recently, this technology has been used to enhance the olfactory performance on fabrics. However keeping the fragrance in the capsule during storage, improving the olfactory benefit and releasing a low amount of formaldehyde is highly challenging. To answer these challenges, Givaudan has developed its own melamine formaldehyde microcapsule, called Mechacaps, which is described in this article. PMID:21528653

  16. Cellobiose dehydrogenase in cellulose degradation

    SciTech Connect

    Eriksson, L.; Igarashi, Kiyohiko; Samejima, Masahiro

    1996-10-01

    Cellobiose dehydrogenase is produced by a variety of fungi. Although it was already discovered during the 70`s, it`s role in cellulose and lignin degradation is yet ambiguous. The enzyme contains both heme and FAD as prosthetic groups, and seems to have a domain specifically designed to bind the enzyme to cellulose. It`s affinity to amorphous cellulose is higher than to crystalline cellulose. We will report on the binding behavior of the enzyme, its usefulness in elucidation of cellulose structures and also, possibilities for applications such as its use in measuring individual and synergistic mechanisms for cellulose degradation by endo- and exo-glucanases.

  17. Formation, Accumulation, and Hydrolysis of Endogenous and Exogenous Formaldehyde-Induced DNA Damage.

    PubMed

    Yu, Rui; Lai, Yongquan; Hartwell, Hadley J; Moeller, Benjamin C; Doyle-Eisele, Melanie; Kracko, Dean; Bodnar, Wanda M; Starr, Thomas B; Swenberg, James A

    2015-07-01

    Formaldehyde is not only a widely used chemical with well-known carcinogenicity but is also a normal metabolite of living cells. It thus poses unique challenges for understanding risks associated with exposure. N(2-)hydroxymethyl-dG (N(2)-HOMe-dG) is the main formaldehyde-induced DNA mono-adduct, which together with DNA-protein crosslinks (DPCs) and toxicity-induced cell proliferation, play important roles in a mutagenic mode of action for cancer. In this study, N(2)-HOMe-dG was shown to be an excellent biomarker for direct adduction of formaldehyde to DNA and the hydrolysis of DPCs. The use of inhaled [(13)CD2]-formaldehyde exposures of rats and primates coupled with ultrasensitive nano ultra performance liquid chromatography-tandem mass spectrometry permitted accurate determinations of endogenous and exogenous formaldehyde DNA damage. The results show that inhaled formaldehyde only reached rat and monkey noses, but not tissues distant to the site of initial contact. The amounts of exogenous adducts were remarkably lower than those of endogenous adducts in exposed nasal epithelium. Moreover, exogenous adducts accumulated in rat nasal epithelium over the 28-days exposure to reach steady-state concentrations, followed by elimination with a half-life (t1/2) of 7.1 days. Additionally, we examined artifact formation during DNA preparation to ensure the accuracy of nonlabeled N(2)-HOMe-dG measurements. These novel findings provide critical new data for understanding major issues identified by the National Research Council Review of the 2010 Environmental Protection Agency's Draft Integrated Risk Information System Formaldehyde Risk Assessment. They support a data-driven need for reflection on whether risks have been overestimated for inhaled formaldehyde, whereas underappreciating endogenous formaldehyde as the primary source of exposure that results in bone marrow toxicity and leukemia in susceptible humans and rodents deficient in DNA repair. PMID:25904104

  18. Formaldehyde-releasers in cosmetics: relationship to formaldehyde contact allergy. Part 2. Patch test relationship to formaldehyde contact allergy, experimental provocation tests, amount of formaldehyde released, and assessment of risk to consumers allergic to formaldehyde.

    PubMed

    de Groot, Anton; White, Ian R; Flyvholm, Mari-Ann; Lensen, Gerda; Coenraads, Pieter-Jan

    2010-01-01

    This is the second part of an article on formaldehyde-releasers in cosmetics. The patch test relationship between the releasers in cosmetics to formaldehyde contact allergy is reviewed and it is assessed whether products preserved with formaldehyde-releasers may contain enough free formaldehyde to pose a threat to individuals with contact allergy to formaldehyde. There is a clear relationship between positive patch test reactions to formaldehyde-releasers and formaldehyde contact allergy: 15% of all reactions to 2-bromo-2-nitropropane-1,3-diol and 40-60% of the reactions to the other releasers are caused by a reaction to the formaldehyde in the test material. There is only fragmented data on the amount of free formaldehyde in cosmetics preserved with formaldehyde donors. However, all releasers (with the exception of 2-bromo-2-nitropropane-1,3-diol, for which adequate data are lacking) can, in the right circumstances of concentration and product composition, release >200 p.p.m. formaldehyde, which may result in allergic contact dermatitis. Whether this is actually the case in any particular product cannot be determined from the ingredient labelling. Therefore, we recommend advising patients allergic to formaldehyde to avoid leave-on cosmetics preserved with quaternium-15, diazolidinyl urea, DMDM hydantoin, or imidazolidinyl urea, acknowledging that many would tolerate some products. PMID:20136876

  19. A method for treating wastewater containing formaldehyde.

    PubMed

    Lotfy, Hesham R; Rashed, I G

    2002-02-01

    Many industrial activities utilise formaldehyde as a key chemical in organic synthesis including: synthesis of special chemicals such as pentaerythritol and ethylene glycol, synthetic resins, paper products, medicinal products and drugs and others, too numerous to mention. Therefore, effluents arising from these applications may contain significant amounts of formaldehyde. In a biodegradation experiments of a wastewater sample containing formaldehyde ranging from 31.5 to 125 mg/l, residual formalin (a solution of formaldehyde gas in water) ranging from 40% to 85%, respectively, was found at the end of the run (16 d) showing the inhibition effect of formalin which increased with the increase in formalin concentration. The biodegradation of formalin decreased significantly at concentrations higher than 300 mg/l. A method to convert formaldehyde to an easily biodegradable substance is herein described. In the commercial manufacture of resins from phenol and formalin the reaction is never completely quantitative. As a result during the dehydration stage phenol and formalin are distilled from the wastewater. Phenol is toxic to several biochemical reactions. However, biological transformation of phenol to a non-toxic entity is possible through specialized microbes. Transformation of phenol is inhibited by the presence of formaldehyde. Biotransformation of phenol in a wastewater containing high concentrations of formaldehyde started shortly after treating the wastewater with calculated amounts of sodium sulphite. Sodium sulphite is believed to react with formaldehyde forming sodium formaldehyde bisulphite, which is not only non-toxic to microorganisms but also a biodegradable substance. From the DO measurements before and after the addition of sodium sulphite, the authors noticed that the dissolved oxygen in a wastewater containing formaldehyde is not affected by the addition of the calculated amount of sodium sulphite, which is just enough to consume the measured amount

  20. 29 CFR 1915.1048 - Formaldehyde.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false Formaldehyde. 1915.1048 Section 1915.1048 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED... Formaldehyde. Note: The requirements applicable to shipyard employment under this section are identical...

  1. 29 CFR 1915.1048 - Formaldehyde.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 7 2012-07-01 2012-07-01 false Formaldehyde. 1915.1048 Section 1915.1048 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED... Formaldehyde. Note: The requirements applicable to shipyard employment under this section are identical...

  2. 29 CFR 1915.1048 - Formaldehyde.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 7 2013-07-01 2013-07-01 false Formaldehyde. 1915.1048 Section 1915.1048 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED... Formaldehyde. Note: The requirements applicable to shipyard employment under this section are identical...

  3. 29 CFR 1915.1048 - Formaldehyde.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 7 2014-07-01 2014-07-01 false Formaldehyde. 1915.1048 Section 1915.1048 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED... Formaldehyde. Note: The requirements applicable to shipyard employment under this section are identical...

  4. Formaldehyde concentrations in biology department teaching facilities

    SciTech Connect

    Korky, J.K.; Schwarz, S.R.; Lustigman, B.K.

    1987-05-01

    As students and faculty in the biological sciences can attest, low grade exposure to formaldehyde by skin contact and inhalation during dissection is quite irritating. Health effects noted upon exposure to formaldehyde at concentrations of 0.1 to 5 ppm are burning of the eyes, lacrimation, and general irritation to the upper respiratory passages. Symptoms reported for higher exposures, 10 to 20 ppm, include coughing, tightening of the chest, headache and palpitation of the heart. Long exposures at 50 to 100 ppm or more might result in pulmonary edema, pneumonitis, and even death. There is also concern with regard to potential long term detrimental effects. Formaldehyde has been cited as a possible carcinogen in animals. It is a known mutagen in laboratory experimental systems involving Drosophilia, grasshoppers, flowering plants, fungi and bacteria. Animal testing has led investigators to postulate that the primary damage resulting from formaldehyde exposure may involve DNA synthesis and ribosomal RNA transcription. The National Institute of Occupational Safety and Health Administration (NIOSH) investigators have been studying occupational exposure to formaldehyde for over a decade in a variety of industries. This study was undertaken to assess formaldehyde concentrations in biology department dissecting facilities in the 1982-1983 academic year in order if routine dissection produces levels of formaldehyde which were unsafe according to NIOSH and OSHA standards. Chronic formaldehyde exposure is cause for greater concern than incidental exposure.

  5. 29 CFR 1915.1048 - Formaldehyde.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Formaldehyde. 1915.1048 Section 1915.1048 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED... Formaldehyde. Note: The requirements applicable to shipyard employment under this section are identical...

  6. NAD + -dependent Formate Dehydrogenase from Plants

    PubMed Central

    Alekseeva, A.A.; Savin, S.S.; Tishkov, V.I.

    2011-01-01

    NAD+-dependent formate dehydrogenase (FDH, EC 1.2.1.2) widely occurs in nature. FDH consists of two identical subunits and contains neither prosthetic groups nor metal ions. This type of FDH was found in different microorganisms (including pathogenic ones), such as bacteria, yeasts, fungi, and plants. As opposed to microbiological FDHs functioning in cytoplasm, plant FDHs localize in mitochondria. Formate dehydrogenase activity was first discovered as early as in 1921 in plant; however, until the past decade FDHs from plants had been considerably less studied than the enzymes from microorganisms. This review summarizes the recent results on studying the physiological role, properties, structure, and protein engineering of plant formate dehydrogenases. PMID:22649703

  7. Formaldehyde Absorption toward W51

    SciTech Connect

    Kogut, A.; Smoot, G.F.; Bennett, C.L.; Petuchowski, S.J.

    1988-04-01

    We have measured formaldehyde (H{sub 2}CO) absorption toward the HII region complex W51A (G49.5-0.4) in the 6 cm and 2 cm wavelength rotational transitions with angular resolution of approximately 4 inch. The continuum HII region shows a large, previously undetected shell structure 5.5 pc along the major axis. We observe no H{sub 2}CO emission in regions of low continuum intensity. The absorption, converted to optical depth, shows a higher degree of clumping than previous maps at lower resolution. The good S/N of the maps allows accurate estimation of the complicated line profiles, showing some of the absorbing clouds to be quite patchy. We list the properties of the opacity spectra for a number of positions both in the clumps and in the more diffuse regions of the absorbing clouds, and derive column densities for the 1{sub 11} and 2{sub 12} rotational levels of ortho-formaldehyde.

  8. Separation of dehydrogenases on polyaminomethylstyrene.

    PubMed

    Schöpp, W; Meinert, S; Thyfronitou, J; Aurich, H

    1975-01-29

    The binding of dehydrogenases, especially alcohol dehydrogenase, and other proteins to several ion exchangers and hydrophobic polymers was investigated. Quantitative parameters for the stability of the polymer-protein complexes (obtained form double reciprocal plots) indicate a high but different affinity of many proteins for polyaminomethylstyrene. The chromatography of a mixture of five dehydrogenases and human serum albumin on polyaminomethylstyrene is described. PMID:237012

  9. Coordinate Regulation of the Escherichia coli Formate Dehydrogenase fdnGHI and fdhF Genes in Response to Nitrate, Nitrite, and Formate: Roles for NarL and NarP

    PubMed Central

    Wang, Henian; Gunsalus, Robert P.

    2003-01-01

    Escherichia coli possesses three distinct formate dehydrogenase enzymes encoded by the fdnGHI, fdhF, and fdoGHI operons. To examine how two of the formate dehyrogenase operons (fdnGHI and fdhF) are expressed anaerobically in the presence of low, intermediate, and high levels of nitrate, nitrite, and formate, chemostat culture techniques were employed with fdnG-lacZ and fdhF-lacZ reporter fusions. Complementary patterns of gene expression were seen. Optimal fdhF-lacZ expression occurred only at low to intermediate levels of nitrate, while high nitrate levels caused up to 10-fold inhibition of gene expression. In contrast, fdnG-lacZ expression was induced 25-fold in the presence of intermediate to high nitrate concentrations. Consistent with prior reports, NarL was able to induce fdnG-lacZ expression. However, NarP could not induce expression; rather, it functioned as an antagonist of fdnG-lacZ expression under low-nitrate conditions (i.e., it was a negative regulator). Nitrite, a reported signal for the Nar sensory system, was unable to stimulate or suppress expression of either formate dehydrogenase operon via NarL and NarP. The different gene expression profiles of the alternative formate dehydrogenase operons suggest that the two enzymes have complementary physiological roles under environmental conditions when nitrate and formate levels are changing. Revised regulatory schemes for NarL- and NarP-dependent nitrate control are presented for each operon. PMID:12923080

  10. Diet-Sensitive Sources of Reactive Oxygen Species in Liver Mitochondria: Role of Very Long Chain Acyl-CoA Dehydrogenases

    PubMed Central

    Cardoso, Ariel R.; Kakimoto, Pâmela A. H. B.; Kowaltowski, Alicia J.

    2013-01-01

    High fat diets and accompanying hepatic steatosis are highly prevalent conditions. Previous work has shown that steatosis is accompanied by enhanced generation of reactive oxygen species (ROS), which may mediate further liver damage. Here we investigated mechanisms leading to enhanced ROS generation following high fat diets (HFD). We found that mitochondria from HFD livers present no differences in maximal respiratory rates and coupling, but generate more ROS specifically when fatty acids are used as substrates. Indeed, many acyl-CoA dehydrogenase isoforms were found to be more highly expressed in HFD livers, although only the very long chain acyl-CoA dehydrogenase (VLCAD) was more functionally active. Studies conducted with permeabilized mitochondria and different chain length acyl-CoA derivatives suggest that VLCAD is also a source of ROS production in mitochondria of HFD animals. This production is stimulated by the lack of NAD+. Overall, our studies uncover VLCAD as a novel, diet-sensitive, source of mitochondrial ROS. PMID:24116206

  11. Formaldehyde Exposures in a University Anatomy Laboratory

    NASA Astrophysics Data System (ADS)

    Winkler, Kyle William

    Air sampling studies were conducted within a university anatomical laboratory during the embalmment of a cadaver in order to determine if dangerous concentrations of formaldehyde existed. Three air sampling studies were conducted in the anatomical laboratory on three separate days that a cadaver was being embalmed. Samples were collected and analyzed using the Occupational Safety and Health Administration (OSHA) Sampling and Analytical Methods: Method 52. Each air sampling study sampled for short term exposure limit (STEL) and time weighted mean (TWA) breathing zone formaldehyde concentrations as well as area TWA formaldehyde concentrations. A personal aldehyde monitor was also used in each air sampling study to sample for breathing zone formaldehyde concentrations. Measured TWA mean exposures to formaldehyde ranged from 0.15--1.3 parts per million (ppm), STEL formaldehyde exposures ranged from 0.019--0.64 ppm, and eight-hour TWAs ranged from 0.03 to 3.6 ppm. All 8-hour TWA formaldehyde concentrations sampled in the anatomy laboratory during an embalmment were less than the permissible exposure limit (PEL) required by OSHA.

  12. Mechanistic study on formaldehyde-induced hepatotoxicity

    SciTech Connect

    Strubelt, O.; Younes, M.; Pentz, R.; Kuehnel, W. )

    1989-01-01

    In isolated, hemoglobin-free perfused livers of fasted rats, formaldehyde at an initial concentration of 10 mmol/l produced toxicity as evidenced by a release of enzymes (GPT, SDH) and of glutathione (mainly GSSG) into the perfusate, an accumulation of calcium in the liver, and a depletion of hepatic glatathione. Formaldehyde also led to an enhanced release of malondialdehyde into the perfusate, indicating peroxidative processes and decreased hepatic oxygen consumption by about 50-70%. The electron microscopic investigation of formaldehyde-exposed livers showed a destruction of the mitochondria (ruptured membranes, loss of the cristae) and some damage of the rough endoplasmic reticulum. Feeding the rats prior to surgery attenuated the hepatotoxic effects of 10 mmol/l formaldehyde. At an initial concentration of 3 mmol/l, formaldehyde did not release enzymes from livers of fed or fasted rats but only from whose glutathione content had been depleted by treatment with phorone (250 mg/kg ip 2 h earlier). Formaldehyde liberated glucose and lactate from the livers of fed but not from those of fasted rats, indicating anaerobic energy supply in the fed state. The hepatotoxic action of formaldehyde is not due to its metabolism to formate or to the 10% methanol added as a stabilizing agent to the commercially available 37% solution named formalin.

  13. Formaldehyde asthma--rare or overlooked

    SciTech Connect

    Nordman, H.; Keskinen, H.; Tuppurainen, M.

    1985-01-01

    A total of 230 persons who had been exposed to formaldehyde and suffered from asthma-like respiratory symptoms were examined between January 1, 1977, and May 31, 1983. All the subjects had a bronchial provocation test with formaldehyde. On the basis of the medical and occupational history of the patients, the specific bronchial provocation test, and other test results, 12 cases were considered to be caused by specific sensitization to formaldehyde. All subjects had been exposed occupationally. An exposure period of between 1 mo and 19 yr preceded the onset of symptoms. Three persons displayed no bronchial hyperreactivity as assessed with a histamine or metacholine provocation test. Eleven of the 12 reactions were triggered by about 2.5 mg/m3 and one reaction by about 1.2 mg/m3 of formaldehyde. The late reaction in 1 patient was completely blocked by the inhalation of 100 micrograms of beclomethasone di-isoproprionate before the challenge with formaldehyde. Seventy-one of the 218 subjects who did not react when they were challenged with formaldehyde demonstrated bronchial hyperreactivity. The authors conclude that formaldehyde asthma, although apparently a rare disease, is under reported. Removal from exposure has a favorable effect on the symptoms. Low domestic exposures, however, may maintain the symptoms in individuals already sensitized.

  14. Urea formaldehyde foam: a dangerous insulation

    SciTech Connect

    Keough, C.

    1980-12-01

    Insulating a home with urea formaldehyde foam can lead to severe health problems due to poisoning from formaldehyde gas. Respiratory problems, allergies, memory loss, and mental problems can result from exposure to foam insulation fumes. Research is now under way at the Chemical Industry Inst., Univ. of Washington, and other institutions to learn more about the health effects of formaldehyde foam and to develop possible remedies to these problems. Several states are either banning or controlling the use of this type of home insulation.

  15. Formaldehyde as hypothetical primer of biohomochirality

    NASA Astrophysics Data System (ADS)

    Goldanskii, Vitalii I.

    1996-07-01

    One of the most intriguing and crucial problems of the prebiotic evolution and the origin of life is the explanation of the origin of biohomochirality. A scheme of conversions originated by formaldehyde (FA) as hypothetical primer of biohomochirality is proposed. The merit of FA as executor of this function is based -inter alia - on the distinguished role of FA as one of the earliest and simplest molecules in both warm, terrestrial and cold, extraterrestrial scenarios of the origin of life. The confirmation of the role of FA as primer of biohomochirality would support the option of an RNA world as an alternative to the protein world. The suggested hypothesis puts forward for the first time a concrete sequence of chemical reactions which can lead to biohomochirality. The spontaneous breaking of the mirror symmetry is secured by the application of the well-known Frank scheme (combination of autocatalysis and ``annihilation'' of L and D enantiomers) to the series of interactions of FA ``trimers'' (i.e. C3H6O3 compounds) of (aaa), (apa) and (app) types, where the monomeric groups (a) means ``achirons'' (a=CHn, n>=2 and C=M, M=C,O) and (p) mean ``prochirons'' (p=HC*OM, M=H,C).

  16. Occupational exposure to formaldehyde in a medical center autopsy service

    SciTech Connect

    Coldiron, V.R.; Ward, J.B. Jr.; Trieff, N.M.; Janssen, H.E. Jr.; Smith, J.H.

    1983-07-01

    The formaldehyde exposures occurring in the autopsy service of a medical complex were evaluated as part of a study to detect genetically harmful effects of chemical exposures. Determination of time-weighted average (TWA) exposures and characterization of the patterns of exposure experienced by individuals with different work responsibilities in this occupational setting were sought. Both general area and breathing zone samples were evaluated. Estimated weekly time-weighted average exposures for pathologists, residents and technicians were determined to be between 0.61 and 1.32 parts per million with little difference between work roles. While the averages were similar, the patterns of exposure of technicians and physicians were different. Technicians were exposed to a baseline level of formaldehyde for a prolonged period of time. In contrast, physicians were exposed for shorter times but experienced higher levels during specific tasks, particularly tissue-sectioning and examination. Evaluations of work procedures and environmental conditions in autopsy services are recommended to reduce personnel exposure to formaldehyde vapor.

  17. 78 FR 34795 - Formaldehyde; Third-Party Certification Framework for the Formaldehyde Standards for Composite...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-10

    ..., automotive, and food and consumer products. The standards used in third-party certification are typically... TPCs and their formaldehyde emissions testing laboratories. EPA would exercise authority to...

  18. Characterization of the functional role of allosteric site residue Asp102 in the regulatory mechanism of human mitochondrial NAD(P)+-dependent malate dehydrogenase (malic enzyme)

    PubMed Central

    2005-01-01

    Human mitochondrial NAD(P)+-dependent malate dehydrogenase (decarboxylating) (malic enzyme) can be specifically and allosterically activated by fumarate. X-ray crystal structures have revealed conformational changes in the enzyme in the absence and in the presence of fumarate. Previous studies have indicated that fumarate is bound to the allosteric pocket via Arg67 and Arg91. Mutation of these residues almost abolishes the activating effect of fumarate. However, these amino acid residues are conserved in some enzymes that are not activated by fumarate, suggesting that there may be additional factors controlling the activation mechanism. In the present study, we tried to delineate the detailed molecular mechanism of activation of the enzyme by fumarate. Site-directed mutagenesis was used to replace Asp102, which is one of the charged amino acids in the fumarate binding pocket and is not conserved in other decarboxylating malate dehydrogenases. In order to explore the charge effect of this residue, Asp102 was replaced by alanine, glutamate or lysine. Our experimental data clearly indicate the importance of Asp102 for activation by fumarate. Mutation of Asp102 to Ala or Lys significantly attenuated the activating effect of fumarate on the enzyme. Kinetic parameters indicate that the effect of fumarate was mainly to decrease the Km values for malate, Mg2+ and NAD+, but it did not notably elevate kcat. The apparent substrate Km values were reduced by increasing concentrations of fumarate. Furthermore, the greatest effect of fumarate activation was apparent at low malate, Mg2+ or NAD+ concentrations. The Kact values were reduced with increasing concentrations of malate, Mg2+ and NAD+. The Asp102 mutants, however, are much less sensitive to regulation by fumarate. Mutation of Asp102 leads to the desensitization of the co-operative effect between fumarate and substrates of the enzyme. PMID:15989682

  19. TGL-mediated lipolysis in Manduca sexta fat body: possible roles for lipoamide-dehydrogenase (LipDH) and high-density lipophorin (HDLp)

    PubMed Central

    Wu, Zengying; Soulages, Jose L; Joshi, Bharat D.; Daniel, Stuart M.; Hager, Zachary J.; Arrese, Estela L

    2014-01-01

    Triglyceride-lipase (TGL) is a major fat body lipase in Manduca sexta. The knowledge of how TGL activity is regulated is very limited. A WWE domain, presumably involved in protein-protein interactions, has been previously identified in the N-terminal region of TGL. In this study, we searched for proteins partners that interact with the N-terminal region of TGL. Thirteen proteins were identified by mass spectrometry, and the interaction with four of these proteins was confirmed by immunoblot. The oxidoreductase lipoamide-dehydrogenase (LipDH) and the apolipoprotein components of the lipid transporter, HDLp, were among these proteins. LipDH is the common component of the mitochondrial α-keto acid dehydrogenase complexes whereas HDLp occurs in the hemolymph. However, subcellular fractionation demonstrated that these two proteins are relatively abundant in the soluble fraction of fat body adipocytes. The cofactor lipoate found in typical LipDH substrates was not detected in TGL. However, TGL proved to have critical thiol groups. Additional studies with inhibitors are consistent with the notion that LipDH acting as a diaphorase could preserve the activity of TGL by controlling the redox state of thiol groups. On the other hand, when TG hydrolase activity of TGL was assayed in the presence of HDLp, the production of diacylglycerol (DG) increased. TGL-HDLp interaction could drive the intracellular transport of DG. TGL may be directly involved in the lipoprotein assembly and loading with DG, a process that occurs in the fat body and is essential for insects to mobilize fatty acids. Overall the study suggests that TGL occurs as a multi-protein complex supported by interactions through the WWE domain. PMID:24333838

  20. Major Role of NAD-Dependent Lactate Dehydrogenases in the Production of l-Lactic Acid with High Optical Purity by the Thermophile Bacillus coagulans.

    PubMed

    Wang, Limin; Cai, Yumeng; Zhu, Lingfeng; Guo, Honglian; Yu, Bo

    2014-12-01

    Bacillus coagulans 2-6 is an excellent producer of optically pure l-lactic acid. However, little is known about the mechanism of synthesis of the highly optically pure l-lactic acid produced by this strain. Three enzymes responsible for lactic acid production-NAD-dependent l-lactate dehydrogenase (l-nLDH; encoded by ldhL), NAD-dependent d-lactate dehydrogenase (d-nLDH; encoded by ldhD), and glycolate oxidase (GOX)-were systematically investigated in order to study the relationship between these enzymes and the optical purity of lactic acid. Lactobacillus delbrueckii subsp. bulgaricus DSM 20081 (a d-lactic acid producer) and Lactobacillus plantarum subsp. plantarum DSM 20174 (a dl-lactic acid producer) were also examined in this study as comparative strains, in addition to B. coagulans. The specific activities of key enzymes for lactic acid production in the three strains were characterized in vivo and in vitro, and the levels of transcription of the ldhL, ldhD, and GOX genes during fermentation were also analyzed. The catalytic activities of l-nLDH and d-nLDH were different in l-, d-, and dl-lactic acid producers. Only l-nLDH activity was detected in B. coagulans 2-6 under native conditions, and the level of transcription of ldhL in B. coagulans 2-6 was much higher than that of ldhD or the GOX gene at all growth phases. However, for the two Lactobacillus strains used in this study, ldhD transcription levels were higher than those of ldhL. The high catalytic efficiency of l-nLDH toward pyruvate and the high transcription ratios of ldhL to ldhD and ldhL to the GOX gene provide the key explanations for the high optical purity of l-lactic acid produced by B. coagulans 2-6. PMID:25217009

  1. Major Role of NAD-Dependent Lactate Dehydrogenases in the Production of l-Lactic Acid with High Optical Purity by the Thermophile Bacillus coagulans

    PubMed Central

    Wang, Limin; Cai, Yumeng; Zhu, Lingfeng; Guo, Honglian

    2014-01-01

    Bacillus coagulans 2-6 is an excellent producer of optically pure l-lactic acid. However, little is known about the mechanism of synthesis of the highly optically pure l-lactic acid produced by this strain. Three enzymes responsible for lactic acid production—NAD-dependent l-lactate dehydrogenase (l-nLDH; encoded by ldhL), NAD-dependent d-lactate dehydrogenase (d-nLDH; encoded by ldhD), and glycolate oxidase (GOX)—were systematically investigated in order to study the relationship between these enzymes and the optical purity of lactic acid. Lactobacillus delbrueckii subsp. bulgaricus DSM 20081 (a d-lactic acid producer) and Lactobacillus plantarum subsp. plantarum DSM 20174 (a dl-lactic acid producer) were also examined in this study as comparative strains, in addition to B. coagulans. The specific activities of key enzymes for lactic acid production in the three strains were characterized in vivo and in vitro, and the levels of transcription of the ldhL, ldhD, and GOX genes during fermentation were also analyzed. The catalytic activities of l-nLDH and d-nLDH were different in l-, d-, and dl-lactic acid producers. Only l-nLDH activity was detected in B. coagulans 2-6 under native conditions, and the level of transcription of ldhL in B. coagulans 2-6 was much higher than that of ldhD or the GOX gene at all growth phases. However, for the two Lactobacillus strains used in this study, ldhD transcription levels were higher than those of ldhL. The high catalytic efficiency of l-nLDH toward pyruvate and the high transcription ratios of ldhL to ldhD and ldhL to the GOX gene provide the key explanations for the high optical purity of l-lactic acid produced by B. coagulans 2-6. PMID:25217009

  2. Glucose-6-Phosphate Dehydrogenase Deficiency.

    PubMed

    Luzzatto, Lucio; Nannelli, Caterina; Notaro, Rosario

    2016-04-01

    G6PD is a housekeeping gene expressed in all cells. Glucose-6-phosphate dehydrogenase (G6PD) is part of the pentose phosphate pathway, and its main physiologic role is to provide NADPH. G6PD deficiency, one of the commonest inherited enzyme abnormalities in humans, arises through one of many possible mutations, most of which reduce the stability of the enzyme and its level as red cells age. G6PD-deficient persons are mostly asymptomatic, but they can develop severe jaundice during the neonatal period and acute hemolytic anemia when they ingest fava beans or when they are exposed to certain infections or drugs. G6PD deficiency is a global health issue. PMID:27040960

  3. Health and Environmental Effects Profile for Formaldehyde

    EPA Science Inventory

    The Health and Environmental Effects Profile for formaldehyde was prepared by the Office of Health and Environmental Assessment, Environmental Criteria and Assessment Office, Cincinnati, OH for the Office of Solid Waste and Emergency Response to support listings of hazardous cons...

  4. HETEROGENOUS PHOTOREACTION OF FORMALDEHYDE WITH HYDROXYL RADICALS

    EPA Science Inventory

    Atmospheric heterogeneous photoreactions occur between formaldehyde and hydroxyl radicals to produce formic acid. hese photoreactions not only occur in clouds, but also in other tropospheric hydrometeors such as precipitation and dew droplets. xperiments were performed by irradia...

  5. Contribution of formaldehyde to respiratory cancer.

    PubMed Central

    Nelson, N; Levine, R J; Albert, R E; Blair, A E; Griesemer, R A; Landrigan, P J; Stayner, L T; Swenberg, J A

    1986-01-01

    This article reviews the available data on the carcinogenicity of formaldehyde from experimental and epidemiologic studies and makes recommendations for further research. Two definitive chronic inhalation bioassays on rodents have demonstrated that formaldehyde produces nasal cancer in rats and mice at 14 ppm and in rats at 6 ppm, which is within the domain of present permissible human exposure (8-hr time-weighted average of 3 ppm, a 5 ppm ceiling, and a 10 ppm short-term exposure limit). Biochemical and physiologic studies in rats have shown that inhaled formaldehyde can depress respiration, inhibit mucociliary clearance, stimulate cell proliferation, and crosslink DNA and protein in the nasal mucosa. No deaths from nasal cancer have been reported in epidemiologic studies of cohorts exposed to formaldehyde, but three case-control studies suggest the possibility of increased risk. Although excesses of lung cancer deaths have been observed in some studies at industrial plants with formaldehyde exposure, uncertainties in interpretation limit the evaluation of these findings. Excess cancers of the brain and of lymphatic and hematopoietic tissues have been reported in certain studies of industrial groups and in most studies of formaldehyde-exposed professionals, but whether these excesses are related to formaldehyde exposure is not known. Several properties of formaldehyde pose unique problems for future research: the mechanisms responsible for its nonlinear response; its probable mechanism of carcinogenic action as a cross-linking agent; its formation in tissues as a normal metabolite; its possible action as a promoter and/or a cocarcinogen; and the importance of glutathione as a host defense at low exposure. PMID:3830109

  6. Report on the Consensus Workshop on Formaldehyde.

    PubMed Central

    1984-01-01

    The Consensus Workshop on Formaldehyde consisted of bringing together scientists from academia, government, industry and public interest groups to address some important toxicological questions concerning the health effects of formaldehyde. The participants in the workshop, the Executive Panel which coordinated the meeting, and the questions posed, all were chosen through a broadly based nomination process in order to achieve as comprehensive a consensus as possible. The subcommittees considered the toxicological problems associated with formaldehyde in the areas of exposure, epidemiology, carcinogenicity/histology/genotoxicity, immunology/sensitization/irritation, structure activity/biochemistry/metabolism, reproduction/teratology, behavior/neurotoxicity/psychology and risk estimation. Some questions considered included the possible human carcinogenicity of formaldehyde, as well as other human health effects, and the interpretation of pathology induced by formaldehyde. These reports, plus introductory material on the procedures used in setting up the Consensus Workshop are presented here. Additionally, there is included a listing of the data base that was made available to the panel chairmen prior to the meeting and was readily accessible to the participants during their deliberations in the meeting. This data base, since it was computerized, was also capable of being searched for important terms. These materials were supplemented by information brought by the panelists. The workshop has defined the consensus concerning a number of major points in formaldehyde toxicology and has identified a number of major deficits in understanding which are important guides to future research. PMID:6525992

  7. Formaldehyde and skin tumorigenesis in Sencar mice

    SciTech Connect

    Iversen, O.H.

    1988-01-01

    Previous experiments involving topical applications of formaldehyde on hairless mouse skin were repeated with SENCAR mice, which are bred for maximum sensitivity to chemical tumorigenesis. Most experimental groups consisted of 32 mice. Topical skin applications of either 100 ..mu..l acetone of about 200 ..mu..l 4% formaldehyde in water twice weekly, resulted in two tumor-bearing animals, each with one small, benign papilloma. A group of 96 mice, treated once with 51.2 ..mu..g DMBA in acetone, developed a total of 107 tumors in 40 tumor-bearing animals. Thus, DMBA is a strong, complete tumorigen also in SENCAR mice. Animals given 51.2 ..mu..g DMBA first and then treated twice weekly with 1% formaldehyde developed a total of 30 tumors in 8 tumor-bearing animals, whereas mice given 51.2 ..mu..g DMBA first, followed by twice weekly treatment with 4% formaldehyde, developed 51 tumors in 15 animals. When two widely accepted, statistical methods were used, there was no significant difference between the groups treated once with DMBA alone and that treated once with DMBA followed by 4% formaldehyde. The results in SENCAR mice confirm that formaldehyde has no skin tumorigenic or carcinogenic potency of its own. It seems doubtful whether it may act as a very weak enhancer of DMBA-induced tumorigenesis, but it has no significant influence on DMBA-induced carcinogenesis.

  8. Report on the Consensus Workshop on Formaldehyde.

    PubMed

    1984-12-01

    The Consensus Workshop on Formaldehyde consisted of bringing together scientists from academia, government, industry and public interest groups to address some important toxicological questions concerning the health effects of formaldehyde. The participants in the workshop, the Executive Panel which coordinated the meeting, and the questions posed, all were chosen through a broadly based nomination process in order to achieve as comprehensive a consensus as possible. The subcommittees considered the toxicological problems associated with formaldehyde in the areas of exposure, epidemiology, carcinogenicity/histology/genotoxicity, immunology/sensitization/irritation, structure activity/biochemistry/metabolism, reproduction/teratology, behavior/neurotoxicity/psychology and risk estimation. Some questions considered included the possible human carcinogenicity of formaldehyde, as well as other human health effects, and the interpretation of pathology induced by formaldehyde. These reports, plus introductory material on the procedures used in setting up the Consensus Workshop are presented here. Additionally, there is included a listing of the data base that was made available to the panel chairmen prior to the meeting and was readily accessible to the participants during their deliberations in the meeting. This data base, since it was computerized, was also capable of being searched for important terms. These materials were supplemented by information brought by the panelists. The workshop has defined the consensus concerning a number of major points in formaldehyde toxicology and has identified a number of major deficits in understanding which are important guides to future research. PMID:6525992

  9. EFFECTS OF FORMALDEHYDE AND PARTICLE-BOUND FORMALDEHYDE ON LUNG MACROPHAGE FUNCTIONS

    EPA Science Inventory

    Dr. George Jakab and associates exposed mice to varying levels (ranging from 0.5 to 15 parts per million [ppm]) of formaldehyde alone or to formaldehyde (5 and 2.5 ppm) mixed with carbon black particles. Carbon black particles were chosen because of their similarity to comb...

  10. Mild mitochondrial metabolic deficits by α-ketoglutarate dehydrogenase inhibition cause prominent changes in intracellular autophagic signaling: Potential role in the pathobiology of Alzheimer's disease.

    PubMed

    Banerjee, Kalpita; Munshi, Soumyabrata; Xu, Hui; Frank, David E; Chen, Huan-Lian; Chu, Charleen T; Yang, Jiwon; Cho, Sunghee; Kagan, Valerian E; Denton, Travis T; Tyurina, Yulia Y; Jiang, Jian Fei; Gibson, Gary E

    2016-06-01

    Brain activities of the mitochondrial enzyme α-ketoglutarate dehydrogenase complex (KGDHC) are reduced in Alzheimer's disease and other age-related neurodegenerative disorders. The goal of the present study was to test the consequences of mild impairment of KGDHC on the structure, protein signaling and dynamics (mitophagy, fusion, fission, biogenesis) of the mitochondria. Inhibition of KGDHC reduced its in situ activity by 23-53% in human neuroblastoma SH-SY5Y cells, but neither altered the mitochondrial membrane potential nor the ATP levels at any tested time-points. The attenuated KGDHC activity increased translocation of dynamin-related protein-1 (Drp1) and microtubule-associated protein 1A/1B-light chain 3 (LC3) from the cytosol to the mitochondria, and promoted mitochondrial cytochrome c release. Inhibition of KGDHC also increased the negative surface charges (anionic phospholipids as assessed by Annexin V binding) on the mitochondria. Morphological assessments of the mitochondria revealed increased fission and mitophagy. Taken together, our results suggest the existence of the regulation of the mitochondrial dynamism including fission and fusion by the mitochondrial KGDHC activity via the involvement of the cytosolic and mitochondrial protein signaling molecules. A better understanding of the link among mild impairment of metabolism, induction of mitophagy/autophagy and altered protein signaling will help to identify new mechanisms of neurodegeneration and reveal potential new therapeutic approaches. PMID:26923918

  11. The Role of Placental 11-Beta Hydroxysteroid Dehydrogenase Type 1 and Type 2 Methylation on Gene Expression and Infant Birth Weight.

    PubMed

    Green, Benjamin B; Armstrong, David A; Lesseur, Corina; Paquette, Alison G; Guerin, Dylan J; Kwan, Lauren E; Marsit, Carmen J

    2015-06-01

    Maternal stress has been linked to infant birth weight outcomes, which itself may be associated with health later in life. The placenta acts as a master regulator for the fetal environment, mediating intrauterine exposures to stress through the activity of genes regulating glucocorticoids, including the 11beta-hydroxysteroid dehydrogenase (HSD11B) type 1 and 2 genes, and so we hypothesized that variation in these genes will be associated with infant birth weight. We investigated DNA methylation levels at six sites across the two genes, as well as mRNA expression for each, and the relationship to infant birth weight. Logistic regressions correcting for potential confounding factors revealed a significant association between methylation at a single CpG site within HSD11B1 and being born large for gestational age. In addition, our analysis identified correlations between methylation and gene expression, including sex-specific transcriptional regulation of HSD11B2. Our work is one of the first comprehensive views of DNA methylation and expression in the placenta for both HSD11B types 1 and 2, linking epigenetic alterations with the regulation of fetal stress and birth weight outcomes. PMID:25788665

  12. Stable Suppression of Lactate Dehydrogenase Activity during Anoxia in the Foot Muscle of Littorina littorea and the Potential Role of Acetylation as a Novel Posttranslational Regulatory Mechanism.

    PubMed

    Shahriari, Ali; Dawson, Neal J; Bell, Ryan A V; Storey, Kenneth B

    2013-01-01

    The intertidal marine snail, Littorina littorea, has evolved to withstand extended bouts of oxygen deprivation brought about by changing tides or other potentially harmful environmental conditions. Survival is dependent on a strong suppression of its metabolic rate and a drastic reorganization of its cellular biochemistry in order to maintain energy balance under fixed fuel reserves. Lactate dehydrogenase (LDH) is a crucial enzyme of anaerobic metabolism as it is typically responsible for the regeneration of NAD(+), which allows for the continued functioning of glycolysis in the absence of oxygen. This study compared the kinetic and structural characteristics of the D-lactate specific LDH (E.C. 1.1.1.28) from foot muscle of aerobic control versus 24 h anoxia-exposed L. littorea. Anoxic LDH displayed a near 50% decrease in V max (pyruvate-reducing direction) as compared to control LDH. These kinetic differences suggest that there may be a stable modification and regulation of LDH during anoxia, and indeed, subsequent dot-blot analyses identified anoxic LDH as being significantly less acetylated than the corresponding control enzyme. Therefore, acetylation may be the regulatory mechanism that is responsible for the suppression of LDH activity during anoxia, which could allow for the production of alternative glycolytic end products that in turn would increase the ATP yield under fixed fuel reserves. PMID:24233354

  13. Stable Suppression of Lactate Dehydrogenase Activity during Anoxia in the Foot Muscle of Littorina littorea and the Potential Role of Acetylation as a Novel Posttranslational Regulatory Mechanism

    PubMed Central

    Shahriari, Ali; Dawson, Neal J.; Bell, Ryan A. V.; Storey, Kenneth B.

    2013-01-01

    The intertidal marine snail, Littorina littorea, has evolved to withstand extended bouts of oxygen deprivation brought about by changing tides or other potentially harmful environmental conditions. Survival is dependent on a strong suppression of its metabolic rate and a drastic reorganization of its cellular biochemistry in order to maintain energy balance under fixed fuel reserves. Lactate dehydrogenase (LDH) is a crucial enzyme of anaerobic metabolism as it is typically responsible for the regeneration of NAD+, which allows for the continued functioning of glycolysis in the absence of oxygen. This study compared the kinetic and structural characteristics of the D-lactate specific LDH (E.C. 1.1.1.28) from foot muscle of aerobic control versus 24 h anoxia-exposed L. littorea. Anoxic LDH displayed a near 50% decrease in Vmax (pyruvate-reducing direction) as compared to control LDH. These kinetic differences suggest that there may be a stable modification and regulation of LDH during anoxia, and indeed, subsequent dot-blot analyses identified anoxic LDH as being significantly less acetylated than the corresponding control enzyme. Therefore, acetylation may be the regulatory mechanism that is responsible for the suppression of LDH activity during anoxia, which could allow for the production of alternative glycolytic end products that in turn would increase the ATP yield under fixed fuel reserves. PMID:24233354

  14. Possible role of NAD-dependent glyceraldehyde-3-phosphate dehydrogenase in growth promotion of Arabidopsis seedlings by low levels of selenium.

    PubMed

    Takeda, Toru; Fukui, Yuki

    2015-01-01

    We explored functional significance of selenium (Se) in Arabidopsis physiology. Se at very low concentrations in cultivation exerted a considerable positive effect on Arabidopsis growth with no indication of oxidative stress, whereas Se at higher concentrations significantly suppressed the growth and brought serious oxidative damage. Respiration, ATP levels, and the activity of NAD-dependent glyceraldehyde-3-phosphate dehydrogenase (NAD-GAPDH) were enhanced in Arabidopsis grown in the medium containing 1.0 μM Se. Addition of an inhibitor of glutathione (GSH) synthesis to the medium abolished both of the Se-dependent growth promotion and NAD-GAPDH up-regulation. Assay of NAD-GAPDH purified from seedlings subjected to Se interventions raised the possibility of a direct connection between the activity of this enzyme and Arabidopsis growth. These results reveal that trace amounts of Se accelerate Arabidopsis growth, and suggest that this pro-growth effect of Se arises enhancing mitochondrial performance in a GSH-dependent manner, in which NAD-GAPDH may serve as a key regulator. PMID:25988618

  15. Two glycerol 3-phosphate dehydrogenase isogenes from Candida versatilis SN-18 play an important role in glycerol biosynthesis under osmotic stress.

    PubMed

    Mizushima, Daiki; Iwata, Hisashi; Ishimaki, Yuki; Ogihara, Jun; Kato, Jun; Kasumi, Takafumi

    2016-05-01

    Two isogenes of glycerol 3-phosphate dehydrogenase (GPD) from Candida versatilis SN-18 were cloned and sequenced. These intronless genes (Cagpd1 and Cagpd2) were both predicted to encode a 378 amino acid polypeptide, and the deduced amino acid sequences mutually showed 76% identity. Interestingly, Cagpd1 and Cagpd2 were located tandemly in a locus of genomic DNA within a 262 bp interval. To our knowledge, this represents a novel instance of isogenic genes relating to glucose metabolism. The stress response element (STRE) was found respectively at -93 to -89 bp upstream of the 5'end of Cagpd1 and -707 to -703 bp upstream of Cagpd2, indicating that these genes are involved in osmotic stress response. In heterologous expression using a gpd1Δgpd2Δ double deletion mutant of Saccharomyces cerevisiae, Cagpd1 and Cagpd2 transformants complemented the function of GPD, with Cagpd2 being much more effective than Cagpd1 in promoting growth and glycerol synthesis. Phylogenetic analysis of the amino acid sequences suggested that Cagpd1p and Cagpd2p are NADP(+)-dependent GPDs (EC 1.1.1.94). However, crude enzyme extract from Cagpd1 and Cagpd2 transformants showed GPD activity with only NAD(+) as cofactor. Hence, both Cagpd1p and Cagpd2p are likely NAD(+)-dependent GPDs (EC 1.1.1.8), similar to GPDs from S. cerevisiae and Candida magnoliae. PMID:26906228

  16. Low-Dose Formaldehyde Delays DNA Damage Recognition and DNA Excision Repair in Human Cells

    PubMed Central

    Luch, Andreas; Frey, Flurina C. Clement; Meier, Regula; Fei, Jia; Naegeli, Hanspeter

    2014-01-01

    Objective Formaldehyde is still widely employed as a universal crosslinking agent, preservative and disinfectant, despite its proven carcinogenicity in occupationally exposed workers. Therefore, it is of paramount importance to understand the possible impact of low-dose formaldehyde exposures in the general population. Due to the concomitant occurrence of multiple indoor and outdoor toxicants, we tested how formaldehyde, at micromolar concentrations, interferes with general DNA damage recognition and excision processes that remove some of the most frequently inflicted DNA lesions. Methodology/Principal Findings The overall mobility of the DNA damage sensors UV-DDB (ultraviolet-damaged DNA-binding) and XPC (xeroderma pigmentosum group C) was analyzed by assessing real-time protein dynamics in the nucleus of cultured human cells exposed to non-cytotoxic (<100 μM) formaldehyde concentrations. The DNA lesion-specific recruitment of these damage sensors was tested by monitoring their accumulation at local irradiation spots. DNA repair activity was determined in host-cell reactivation assays and, more directly, by measuring the excision of DNA lesions from chromosomes. Taken together, these assays demonstrated that formaldehyde obstructs the rapid nuclear trafficking of DNA damage sensors and, consequently, slows down their relocation to DNA damage sites thus delaying the excision repair of target lesions. A concentration-dependent effect relationship established a threshold concentration of as low as 25 micromolar for the inhibition of DNA excision repair. Conclusions/Significance A main implication of the retarded repair activity is that low-dose formaldehyde may exert an adjuvant role in carcinogenesis by impeding the excision of multiple mutagenic base lesions. In view of this generally disruptive effect on DNA repair, we propose that formaldehyde exposures in the general population should be further decreased to help reducing cancer risks. PMID:24722772

  17. Formaldehyde OMI operational retrieval upgrades

    NASA Astrophysics Data System (ADS)

    Gonzalez Abad, G.; Chance, K.; Liu, X.

    2013-05-01

    Total column of formaldehyde (HCHO), a proxy for biogenic emissions, can be observed from satellites using the ultraviolet region of the spectrum. The operational HCHO retrievals from the Ozone Monitoring Instrument (OMI) on board the AURA satellite, part of NASA's A-train constellation of Earth Observing satellites, are described. The operational retrieval, based on a basic optical absorption spectroscopy (BOAS) algorithm, has been affected by the degradation of the instrument especially from 2008 onwards. The most significant problems are the unrealistic increasing high background concentrations of HCHO retrieved from OMI and the row anomaly. An upgrade for the original operational algorithm is therefore needed to ensure its trend quality and to account for these difficulties. The strategies implemented to deal with the instrumental degradation are presented here. Air mass factors (AMFs) in the current fitting window show significant wavelength dependence. Fitting uncertainties can potentially be improved by including shorter wavelengths as long as the AMFs wavelength dependence is taken into account. As part of these improvements a look-up table of wavelength-dependent AMFs have been calculated. Using this new table it is possible to retrieve the HCHO total column directly, weighting the HCHO cross sections with the wavelength-dependent AMFs. Additionally, the pixels affected by the row anomaly are now flagged in the level 2 data generated with the upgraded algorithm.

  18. Formaldehyde absorption toward W51

    NASA Technical Reports Server (NTRS)

    Kogut, A.; Smoot, G. F.; Bennett, C. L.; Petuchowski, S. J.

    1989-01-01

    Formaldehyde (H2CO) absorption toward the H II region complex W51A (G49.5 - 0.4) in the 6 cm and 2 cm wavelength rotational transitions has been measured with angular resolution of about 0.15 pc. The continuum H II region shows a large, previously undetected shell structure 5.5 pc along the major axis. The absorption, converted to optical depth, shows a higher degree of clumping throughout the map than previous maps at lower resolution; in particular, two narrow regions of enhanced opacity are observed. The absorption in the velocity range 64-67 km/s LSR extends over most of the region, with an observed velocity gradient of 5.2 km/s pc. The opacity structure largely parallels the velocity structure, with a ridge of enhanced opacity to the north of the highest velocity feature. The S/N of the maps allows accurate modeling of the spectral profiles. Nine distinct clumps in the foreground clouds have been identified and parametrized, and column densities for the 1(11) and 2(12) rotational levels of orthoformaldehyde have been derived.

  19. Health effects of urea formaldehyde foam insulation: evidence of causation.

    PubMed Central

    Norman, G R; Newhouse, M T

    1986-01-01

    Studies of health effects of urea formaldehyde foam insulation (UFFI) were critically reviewed by means of accepted rules for evidence of causation. Three categories of health effects were examined: reported symptoms, primarily of the upper respiratory tract, lower respiratory tract disease and cancer. Most of the studies purporting to demonstrate health effects of UFFI failed to meet minimal methodologic criteria for evidence of causation. Evidence from the adequate studies provides little support for the hypothesis of a causative role of UFFI in health problems. PMID:3512066

  20. Characterization of xylitol dehydrogenase from Debaryomyces hansenii

    SciTech Connect

    Girio, F.M.; Amaral-Collaco, M.T.; Pelica, F.

    1996-01-01

    The xylitol dehydrogenase (EC 1.1.1.9) from xylose-grown cells of Debaryomyces hansenii was partially purified in two chromatographic steps, and characterization studies were carried out in order to investigate the role of the xylitol dehydrogenase-catalyzed step in the regulation of D-xylose metabolism. The enzyme was most active at pH 9.0-9.5, and exhibited a broad polyol specificity. The Michaelis constants for xylitol and NAD{sup +} were 16.5 and 0.55 mM, respectively. Ca{sup 2+}, Mg{sup 2+}, and Mn{sup 2+} did not affect the enzyme activity. Conversely, Zn{sup 2+}, Cd{sup 2+}, and Co{sup 2+} strongly inhibited the enzyme activity. It was concluded that NAD{sup +}-xylitol dehydrogenase from D. hansenii has similarities with other xylose-fermenting yeasts in respect to optimal pH, substrate specificity, and K{sub m} value for xylitol, and therefore should be named L-iditol:NAD{sup +}-5-oxidoreductase (EC 1.1.1.14). The reason D. hansenii is a good xylitol producer is not because of its value of K for xylitol, which is low enough to assure its fast oxidation by NAD{sup +}-xylitol dehydrogenase. However, a higher K{sub m} value of xylitol dehydrogenase for NAD{sup +} compared to the K{sub m} values of other xylose-fermenting yeasts may be responsible for the higher xylitol yields. 22 refs., 4 figs., 2 tabs.

  1. Difficulties in recognition of pyruvate dehydrogenase complex deficiency on the basis of clinical and biochemical features. The role of next-generation sequencing

    PubMed Central

    Ciara, E.; Rokicki, D.; Halat, P.; Karkucińska-Więckowska, A.; Piekutowska-Abramczuk, D.; Mayr, J.; Trubicka, J.; Szymańska-Dębińska, T.; Pronicki, M.; Pajdowska, M.; Dudzińska, M.; Giżewska, M.; Krajewska-Walasek, M.; Książyk, J.; Sperl, W.; Płoski, R.; Pronicka, E.

    2016-01-01

    Pyruvate dehydrogenase complex (PDHc) defect is a well-known cause of mitochondrial disorders (MD) with at least six responsible genes (PDHA1, PDHB, DLAT, DLD, PDHX, PDP1). The aim of this work was to assess the diagnostic value of biochemical methods in recognition of PDHc defect in Polish patients with suspicion of MD. In the first step, Western blot of the E1α subunit was performed on 86 archive muscle bioptates with suspicion of MD. In the second step, Sanger PDHA1 sequencing was performed in 21 cases with low E1α expression. In the third step, 7 patients with negative results of PDHA1 sequencing were subjected to whole-exome sequencing (WES). This protocol revealed 4 patients with PDHA1 and one with DLD mutations. Four additional probands were diagnosed outside the protocol (WES or Sanger sequencing). The molecular characterization of PDHc defect was conducted in a total of 9 probands: 5 according to and 4 off the protocol. Additionally, two affected relatives were recognized by a family study. Altogether we identified seven different PDHA1 changes, including two novel variants [c.464T > C (p.Met155Thr) and c.856_859dupACTT (p.Arg288Leufs*10)] and one DLD variant. The lactate response to glucose load in the PDHA1 subset was compared to a subset of non PDHc-related MD. Opposite responses were observed, with an increase of 23% and decrease of 27%, respectively. The results show that determining lactate response to glucose load and muscle E1α expression may contribute to distinguishing PDHc-related and other MD, however, WES is becoming the method of choice for MD diagnostics. PMID:27144126

  2. Reversible phosphorylation regulation of NADPH-linked polyol dehydrogenase in the freeze-avoiding gall moth, Epiblema scudderiana: role in glycerol metabolism.

    PubMed

    Holden, Helen A; Storey, Kenneth B

    2011-05-01

    Larvae of the goldenrod gall moth, Epiblema scudderiana, use a freeze avoidance strategy of cold hardiness to survive the winter. A key metabolic adaption that supports subzero survival is the accumulation of large amounts of glycerol as a colligative antifreeze. Production of glycerol relies on polyol dehydrogenase (PDH) which catalyzes the NADPH-dependent conversion of glyceraldehyde into glycerol. Kinetic analysis of PDH from E. scudderiana revealed significant changes in properties as a result of subzero temperature acclimation; the K(m) for glyceraldehyde in 5°C-acclimated larvae was 7.0 mM and doubled in - 15°C-exposed larvae. This change suggested that PDH is regulated by a state-dependent covalent modification. Indeed, high and low K(m) forms could be interconverted by incubating larval extracts in vitro under conditions that stimulated either endogenous protein kinases or protein phosphatases. Protein kinase incubations doubled the K(m) glyceraldehyde of the 5°C enzyme, whereas protein phosphatase incubations decreased the K(m) of the - 15°C enzyme by about 50%. PDH was purified by ion exchange and affinity chromatography steps and then subjected to electrophoresis. Staining with ProQ Diamond phosphoprotein stain showed a much higher phosphate content of PDH from - 15°C-acclimated larvae, a result that was further confirmed by immunoblotting that showed a much greater phosphoserine content on the - 15°C enzyme. These experiments established that PDH is regulated by state-dependent reversible phosphorylation in E. scudderiana and suggest that this regulatory mechanism makes a significant contribution to controlling the synthesis, maintenance, and degradation of glycerol pools over the winter months. PMID:21400585

  3. Difficulties in recognition of pyruvate dehydrogenase complex deficiency on the basis of clinical and biochemical features. The role of next-generation sequencing.

    PubMed

    Ciara, E; Rokicki, D; Halat, P; Karkucińska-Więckowska, A; Piekutowska-Abramczuk, D; Mayr, J; Trubicka, J; Szymańska-Dębińska, T; Pronicki, M; Pajdowska, M; Dudzińska, M; Giżewska, M; Krajewska-Walasek, M; Książyk, J; Sperl, W; Płoski, R; Pronicka, E

    2016-06-01

    Pyruvate dehydrogenase complex (PDHc) defect is a well-known cause of mitochondrial disorders (MD) with at least six responsible genes (PDHA1, PDHB, DLAT, DLD, PDHX, PDP1). The aim of this work was to assess the diagnostic value of biochemical methods in recognition of PDHc defect in Polish patients with suspicion of MD. In the first step, Western blot of the E1α subunit was performed on 86 archive muscle bioptates with suspicion of MD. In the second step, Sanger PDHA1 sequencing was performed in 21 cases with low E1α expression. In the third step, 7 patients with negative results of PDHA1 sequencing were subjected to whole-exome sequencing (WES). This protocol revealed 4 patients with PDHA1 and one with DLD mutations. Four additional probands were diagnosed outside the protocol (WES or Sanger sequencing). The molecular characterization of PDHc defect was conducted in a total of 9 probands: 5 according to and 4 off the protocol. Additionally, two affected relatives were recognized by a family study. Altogether we identified seven different PDHA1 changes, including two novel variants [c.464T > C (p.Met155Thr) and c.856_859dupACTT (p.Arg288Leufs*10)] and one DLD variant. The lactate response to glucose load in the PDHA1 subset was compared to a subset of non PDHc-related MD. Opposite responses were observed, with an increase of 23% and decrease of 27%, respectively. The results show that determining lactate response to glucose load and muscle E1α expression may contribute to distinguishing PDHc-related and other MD, however, WES is becoming the method of choice for MD diagnostics. PMID:27144126

  4. Evidence for a Role for NAD(P)H Dehydrogenase in Concentration of CO2 in the Bundle Sheath Cell of Zea mays1[OPEN

    PubMed Central

    Schultes, Neil P.; McHale, Neil A.; Zelitch, Israel

    2016-01-01

    Prior studies with Nicotiana and Arabidopsis described failed assembly of the chloroplastic NDH [NAD(P)H dehydrogenase] supercomplex by serial mutation of several subunit genes. We examined the properties of Zea mays leaves containing Mu and Ds insertions into nuclear gene exons encoding the critical o- and n-subunits of NDH, respectively. In vivo reduction of plastoquinone in the dark was sharply diminished in maize homozygous mutant compared to normal leaves but not to the extreme degree observed for the corresponding lesions in Arabidopsis. The net carbon assimilation rate (A) at high irradiance and saturating CO2 levels was reduced by one-half due to NDH mutation in maize although no genotypic effect was evident at very low CO2 levels. Simultaneous assessment of chlorophyll fluorescence and A in maize at low (2% by volume) and high (21%) O2 levels indicated the presence of a small, yet detectable, O2-dependent component of total linear photosynthetic electron transport in 21% O2. This O2-dependent component decreased with increasing CO2 level indicative of photorespiration. Photorespiration was generally elevated in maize mutant compared to normal leaves. Quantification of the proportion of total electron transport supporting photorespiration enabled estimation of the bundle sheath cell CO2 concentration (Cb) using a simple kinetic model of ribulose bisphosphate carboxylase/oxygenase function. The A versus Cb relationships overlapped for normal and mutant lines consistent with occurrence of strictly CO2-limited photosynthesis in the mutant bundle sheath cell. The results are discussed in terms of a previously reported CO2 concentration model [Laisk A, Edwards GE (2000) Photosynth Res 66: 199–224]. PMID:27002061

  5. Local corticosterone activation by 11β-hydroxysteroid dehydrogenase 1 in keratinocytes: the role in narrow-band UVB-induced dermatitis

    PubMed Central

    Itoi-Ochi, Saori; Terao, Mika; Murota, Hiroyuki; Katayama, Ichiro

    2016-01-01

    ABSTRACT Keratinocytes are known to synthesize cortisol through activation of the enzyme 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1). To confirm the function of 11β-HSD1 in keratinocytes during inflammation in vivo, we created keratinocyte-specific-11β-HSD1 knockout mice (K5-Hsd11b1-KO mice) and analyzed the response to narrow-band ultraviolet B (NB-UVB) irradiation. Firstly, we measured the mRNA and protein levels of 11β-HSD1 following NB-UVB irradiation and found that the expression of 11β-HSD1 in keratinocytes of mouse ear skin was enhanced at 3 and 24 hours after 250 mJ/cm2, 500 mJ/cm2, 1 J/cm2, and 2 J/cm2 NB-UVB irradiation. Next, we determined that 24 hours after exposure to 1 J/cm2 NB-UVB irradiation, the numbers of F4/80-, CD45-, and Gr-1-positive cells were increased in K5-Hsd11b1-KO mice compared to wild type (WT) mice. Furthermore, the expression of the chemokine (C-X-C-motif) ligand 1 (CXCL1) and interleukin (IL)-6 was also significantly enhanced in NB-UVB-irradiated K5-Hsd11b1-KO mice compared with WT mice. In addition, activation of nuclear factor-kappa B (NF-κB) after NB-UVB irradiation was enhanced in K5-Hsd11b1-KO mice compared to that in WT mice. Thus, NB-UVB-induced inflammation is augmented in K5-Hsd11b1-KO mice compared with WT mice. These results indicate that 11β-HSD1 may suppress NB-UVB-induced inflammation via inhibition of NF-κB activation. PMID:27195053

  6. Structural and Functional Consequences of Coenzyme Binding to the Inactive Asian Variant of Mitochondrial Aldehyde Dehydrogenase: Roles of Residues 475 and 487

    SciTech Connect

    Larson,H.; Zhou, J.; Chen, Z.; Stamler, J.; Weiner, H.; Hurley, T.

    2007-01-01

    The common mitochondrial aldehyde dehydrogenase (ALDH2) ALDH2*2 polymorphism is associated with impaired ethanol metabolism and decreased efficacy of nitroglycerin treatment. These physiological effects are due to the substitution of Lys for Glu-487 that reduces the k{sub cat} for these processes and increases the K{sub m} for NAD{sup +}, as compared with ALDH2. In this study, we sought to understand the nature of the interactions that give rise to the loss of structural integrity and low activity in ALDH2*2 even when complexed with coenzyme. Consequently, we have solved the crystal structure of ALDH2*2 complexed with coenzyme to 2.5 {angstrom}. We have also solved the structures of a mutated form of ALDH2 where Arg-475 is replaced by Gln (R475Q). The structural and functional properties of the R475Q enzyme are intermediate between those of wild-type and the ALDH2*2 enzymes. In both cases, the binding of coenzyme restores most of the structural deficits observed in the apoenzyme structures. The binding of coenzyme to the R475Q enzyme restores its structure and catalytic properties to near wild-type levels. In contrast, the disordered helix within the coenzyme binding pocket of ALDH2*2 is reordered, but the active site is only partially reordered. Consistent with the structural data, ALDH2*2 showed a concentration-dependent increase in esterase activity and nitroglycerin reductase activity upon addition of coenzyme, but the levels of activity do not approach those of the wild-type enzyme or that of the R475Q enzyme. The data presented shows that Glu-487 maintains a critical function in linking the structure of the coenzyme binding site to that of the active site through its interactions with Arg-264 and Arg-475, and in doing so, creates the stable structural scaffold conducive to catalysis.

  7. Evidence for a Role for NAD(P)H Dehydrogenase in Concentration of CO2 in the Bundle Sheath Cell of Zea mays.

    PubMed

    Peterson, Richard B; Schultes, Neil P; McHale, Neil A; Zelitch, Israel

    2016-05-01

    Prior studies with Nicotiana and Arabidopsis described failed assembly of the chloroplastic NDH [NAD(P)H dehydrogenase] supercomplex by serial mutation of several subunit genes. We examined the properties of Zea mays leaves containing Mu and Ds insertions into nuclear gene exons encoding the critical o- and n-subunits of NDH, respectively. In vivo reduction of plastoquinone in the dark was sharply diminished in maize homozygous mutant compared to normal leaves but not to the extreme degree observed for the corresponding lesions in Arabidopsis. The net carbon assimilation rate (A) at high irradiance and saturating CO2 levels was reduced by one-half due to NDH mutation in maize although no genotypic effect was evident at very low CO2 levels. Simultaneous assessment of chlorophyll fluorescence and A in maize at low (2% by volume) and high (21%) O2 levels indicated the presence of a small, yet detectable, O2-dependent component of total linear photosynthetic electron transport in 21% O2 This O2-dependent component decreased with increasing CO2 level indicative of photorespiration. Photorespiration was generally elevated in maize mutant compared to normal leaves. Quantification of the proportion of total electron transport supporting photorespiration enabled estimation of the bundle sheath cell CO2 concentration (Cb) using a simple kinetic model of ribulose bisphosphate carboxylase/oxygenase function. The A versus Cb relationships overlapped for normal and mutant lines consistent with occurrence of strictly CO2-limited photosynthesis in the mutant bundle sheath cell. The results are discussed in terms of a previously reported CO2 concentration model [Laisk A, Edwards GE (2000) Photosynth Res 66: 199-224]. PMID:27002061

  8. Genetics Home Reference: pyruvate dehydrogenase deficiency

    MedlinePlus

    ... control the activity of the complex: pyruvate dehydrogenase phosphatase turns on (activates) the complex, while pyruvate dehydrogenase ... binding protein (the PDHX gene), and pyruvate dehydrogenase phosphatase (the PDP1 gene) have been identified in people ...

  9. Evidence for chemical and cellular reactivities of the formaldehyde releaser bronopol, independent of formaldehyde release.

    PubMed

    Kireche, Mustapha; Peiffer, Jean-Luc; Antonios, Diane; Fabre, Isabelle; Giménez-Arnau, Elena; Pallardy, Marc; Lepoittevin, Jean-Pierre; Ourlin, Jean-Claude

    2011-12-19

    Formaldehyde and formaldehyde releasers are widely used preservatives and represent an important group of skin sensitizers. Formaldehyde is very often suspected to be the sensitizing agent of formaldehyde-releasers; however, many reported clinical cases of contact allergy to these molecules such as bronopol (2-bromo-2-nitropropane-1,3-diol) indicate negative skin reactions to formaldehyde suggesting a more complex mechanism. The aim of this study was to compare the chemical reactivity and biological activity of formaldehyde with those of two formaldehyde releasers: 2-bromo-2-nitropropane-1,3-diol and 1,3-dimethylol-5,5-dimethylhydantoin. A key step in the sensitization to chemicals is the formation of the hapten-protein antigenic complex via covalent binding between the chemical sensitizer and amino acids in proteins. The chemical reactivity of the three compounds was thus addressed using (13)C NMR analysis of adduct formation upon incubation with a set of nucleophilic amino acids. The biological activity was measured in two in vitro models based on dendritic cells and a monocytic cell line (CD34-DC and THP-1 model) through monitoring of a panel of biomarkers. The results obtained show that 2-bromo-2-nitropropane-1,3-diol produces low amount of free formaldehyde in physiological buffers but that its degradation generates various molecules including 2-bromoethanol. In addition, 2-bromo-2-nitropropane-1,3-diol also generates adducts with amino acids, not observed with formaldehyde alone, that could be explained by the reactivity of 2-bromoethanol. In parallel, in a cellular approach using the human monocytic THP-1 cell line, 2-bromo-2-nitropropane-1,3-diol activates THP-1 cells at concentrations that are not correlated to simple formaldehyde release. This observation is confirmed in the more physiological model CD34-DC. Moreover, in the THP-1 model, the expression profiles of several biomarkers are specific to 2-bromo-2-nitropropane-1,3-diol. Finally, the use in the

  10. Formaldehyde assay by capacitance versus voltage and impedance measurements using bi-layer bio-recognition membrane.

    PubMed

    Ben Ali, M; Korpan, Y; Gonchar, M; El'skaya, A; Maaref, M A; Jaffrezic-Renault, N; Martelet, C

    2006-12-15

    A novel formaldehyde sensitive biosensor based on bacterial formaldehyde dehydrogenase (FDH) as a bio-recognition element has been developed. The bio-recognition membrane had bi-layer architecture and consisted of FDH, cross-linked with albumin, and of the cofactor NAD at a high concentration level (first layer). The second layer was a negatively charged Nafion membrane, which prevented a leakage of negatively charged NAD molecules from the bio-membrane. As transducers, gold electrodes SiO(2)/Si/SiO(2)/Ti/Au and electrolyte-insulator-semiconductor Si/SiO(2) (EIS) structures have been used. Changes in capacitance and impedance properties of the bio-recognition membrane have been used for monitoring formaldehyde concentration in a bulk solution. It has been shown that formaldehyde can be detected within a concentration range from 1 microM to 20mM depending on the type of transduction used, with a detection limit of 1 and 100 microM for gold-based and EIS-based transducers, respectively. PMID:16516460

  11. Mechanistic and dose considerations for supporting adverse pulmonary physiology in response to formaldehyde

    SciTech Connect

    Thompson, Chad M. Subramaniam, Ravi P.; Grafstroem, Roland C.

    2008-12-15

    Induction of airway hyperresponsiveness and asthma from formaldehyde inhalation exposure remains a debated and controversial issue. Yet, recent evidences on pulmonary biology and the pharmacokinetics and toxicity of formaldehyde lend support for such adverse effects. Specifically, altered thiol biology from accelerated enzymatic reduction of the endogenous bronchodilator S-nitrosoglutathione and pulmonary inflammation from involvement of Th2-mediated immune responses might serve as key events and cooperate in airway pathophysiology. Understanding what role these mechanisms play in various species and lifestages (e.g., child vs. adult) could be crucial for making more meaningful inter- and intra-species dosimetric extrapolations in human health risk assessment.

  12. Formaldehyde content of atmospheric aerosol.

    PubMed

    Toda, Kei; Yunoki, Satoru; Yanaga, Akira; Takeuchi, Masaki; Ohira, Shin-Ichi; Dasgupta, Purnendu K

    2014-06-17

    Formaldehyde (HCHO) is a highly soluble polar molecule with a large sticking coefficient and thus likely exists in both gaseous and particulate forms. Few studies, however, address particulate HCHO (HCHO(p)). Some report that HCHO(p) concentrations (obtained only with long duration sampling) are very low. The lack of data partly reflects the difficulty of specifically measuring HCHO(p). Long duration filter sampling may not produce meaningful results for a variety of reasons. In this work, gaseous HCHO (HCHO(g)) and (HCHO(p)) were, respectively, collected with a parallel plate wet denuder (PPWD) followed by a mist chamber/hydrophilic filter particle collector (PC). The PPWD quantitatively removed HCHO(g) and the PC then collected the transmitted aerosol. The collected HCHO from either device was alternately analyzed by Hantzsch reaction-based continuous flow fluorometry. Each gas and particle phase measurement took 5 min each, with a 10 min cycle. The limits of detection were 0.048 and 0.0033 μg m(-3), respectively, for HCHO(g) and HCHO(p). The instrument was deployed in three separate campaigns in a forest station in western Japan in March, May, and July of 2013. Based on 1296 data pairs, HCHO(p), was on the average, 5% of the total HCHO. Strong diurnal patterns were observed, with the HCHO(p) fraction peaking in the morning. The relative humidity dependence of the partition strongly suggests that it is driven by the liquid water content of the aerosol phase. However, HCHO(p) was 100× greater than that expected from Henry's law. We propose that the low water activity in the highly saline droplets lead to HCHO oligomerization. PMID:24857706

  13. New Mechanism of Bone Cancer Pain: Tumor Tissue-Derived Endogenous Formaldehyde Induced Bone Cancer Pain via TRPV1 Activation.

    PubMed

    Wan, You

    2016-01-01

    In recent years, our serial investigations focused on the role of cancer cells-derived endogenous formaldehyde in bone cancer pain. We found that cancer cells produced formaldehyde through demethylation process by serine hydroxymethyltransferase (SHMT1 and SHMT2) and lysine-specific histone demethylase 1 (LSD1). When the cancer cells metastasized into bone marrow, the elevated endogenous formaldehyde induced bone cancer pain through activation on the transient receptor potential vanilloid subfamily member 1 (TRPV1) in the peripheral nerve fibers. More interestingly, TRPV1 expressions in the peripheral fibers were upregulated by the local insulin-like growth factor I (IGF-I) produced by the activated osteoblasts. In conclusion, tumor tissue-derived endogenous formaldehyde induced bone cancer pain via TRPV1 activation. PMID:26900062

  14. Fabricating polystyrene fiber-dehydrogenase assemble as a functional biocatalyst.

    PubMed

    An, Hongjie; Jin, Bo; Dai, Sheng

    2015-01-01

    Immobilization of the enzymes on nano-structured materials is a promising approach to enhance enzyme stabilization, activation and reusability. This study aimed to develop polystyrene fiber-enzyme assembles to catalyze model formaldehyde to methanol dehydrogenation reaction, which is an essential step for bioconversion of CO2 to a renewable bioenergy. We fabricated and modified electrospun polystyrene fibers, which showed high capability to immobilize dehydrogenase for the fiber-enzyme assembles. Results from evaluation of biochemical activities of the fiber-enzyme assemble showed that nitriation with the nitric/sulfuric acid ratio (v/v, 10:1) and silanization treatment delivered desirable enzyme activity and long-term storage stability, showing great promising toward future large-scale applications. PMID:25435501

  15. Production of Melamine-Formaldehyde PCM Microcapsules with Ammonia Scavenger used for Residual Formaldehyde Reduction.

    PubMed

    Sumiga, Boštjan; Knez, Emil; Vrtačnik, Margareta; Ferk-Savec, Vesna; Starešinič, Marica; Boh, Bojana

    2011-03-01

    Paraffinic phase change materials (PCM) were microencapsulated by in situ polymerization of melamine-formaldehyde prepolymers. Partly methylated trimethylolmelamine was used as an aminoaldehyde prepolymer for the microcapsule wall, a styrene-maleic acid anhydride copolymer as an emulsifier and modifying agent, and ammonia as a scavenger for reducing residual formaldehyde. For the determination of residual formaldehyde in a ppm concentration range, EDANA and malachite green analytical methods were studied, and the EDANA 210.1-99 was applied for the determination of residual formaldehyde in 25 samples of microcapsules, produced in a 200-L reactor. A linear correlation was observed between the added ammonia scavenger concentration and the reduction of residual formaldehyde concentration. Compared with 0.45% (4500 ppm) formaldehyde in a non-treated microcapsule suspension, with ammonia scavenger concentrations 0.80, 0.90 and 1.35%, the concentration of residual formaldehyde dropped to 0.27, 0.20 and 0.09% (i.e. 2700, 2000 and 900 ppm), respectively. Morphological characterisation of microcapsules by SEM and microcapsule wall permeability measurements by gravimetry / mass loss at an elevated temperature (135 °C) suggested that ammonia positively contributed to the wall elasticity / durability, while microcapsules with no ammonia scavenger added tended to have more brittle walls, and were more prone to cracking. PMID:24061938

  16. Understanding the Molecular Mechanism(s) of Formaldehyde-induced DNA-protein Crosslink Repair

    EPA Science Inventory

    Although formaldehyde has been shown to induce many kinds of DNA damage both in in vitro and in vivo assay systems, initial DNA-protein crosslink (DPC) formation might play a major role in FA-induced mutagenesis and carcinogenesis. Several DNA repair pathways, such as base excisi...

  17. Cytokinins in the Bryophyte Physcomitrella patens: Analyses of Activity, Distribution, and Cytokinin Oxidase/Dehydrogenase Overexpression Reveal the Role of Extracellular Cytokinins1[W

    PubMed Central

    von Schwartzenberg, Klaus; Núñez, Marta Fernández; Blaschke, Hanna; Dobrev, Petre I.; Novák, Ondrej; Motyka, Václav; Strnad, Miroslav

    2007-01-01

    Ultra-performance liquid chromatography-tandem mass spectrometry was used to establish the cytokinin profile of the bryophyte Physcomitrella patens (Hedw.) B.S.G.; of 40 analyzed cytokinins, 20 were detected. cis-Zeatin-riboside-O-glucoside, N6-(Δ2-isopentenyl)adenosine-5′-monophosphate (iPRMP), and trans-zeatin-riboside-O-glucoside were the most abundant intracellular cytokinins. In addition, the aromatic cytokinins N6-benzyladenosine (BAR), N6-benzyladenine, meta-, and ortho-topolin were detected. Unexpectedly, the most abundant extracellular cytokinin was the nucleotide iPRMP, and its identity was confirmed by quadrupole time-of-flight mass spectrometry. The effects of overexpressing a heterologous cytokinin oxidase/dehydrogenase (CKX; EC 1.4.3.18/1.5.99.12) gene (AtCKX2 from Arabidopsis [Arabidopsis thaliana]) on the intracellular and extracellular distribution of cytokinins was assessed. In cultures of CKX-transformed plants, ultra-performance liquid chromatography-tandem mass spectrometry measurements showed that there were pronounced reductions in the extracellular concentrations of N6-(Δ2-isopentenyl)adenine (iP) and N6-(Δ2-isopentenyl)adenosine (iPR), but their intracellular cytokinin concentrations were only slightly affected. In vitro and in vivo measured CKX activity was shown to be strongly increased in the transformants. Major phenotypic changes observed in the CKX-overexpressing plants included reduced and retarded budding, absence of sexual reproduction, and abnormal protonema cells. In bud-induction bioassays with wild-type Physcomitrella, the nucleotides iPRMP, trans-zeatin-riboside-5′-monophosphate, BAR monophosphate, and the cis-zeatin forms cZ and cZR had no detectable effects, while the activities displayed by other selected cytokinins were in the following order: iP > tZ > N6-benzyladenine > BAR > iPR > tZR > meta-topolin > dihydrozeatin > ortho-topolin. The results on wild type and CKX transgenics suggest that extracellular iP and i

  18. Exposure to formaldehyde: effects of pulmonary function

    SciTech Connect

    Alexandersson, R.; Kolmodin-Hedman, B.; Hedenstierna, G.

    1982-09-01

    Forty-seven subjects exposed to formaldehyde (mean air concentration 0.45 mg/m/sup 3/) and 20 unexposed subjects, all of whom were employed at a carpentry shop, were studied with regard to symptoms and pulmonary function. Symptoms involving eyes and throat as well as chest oppression were significantly more common in the exposed subjects than in the unexposed controls. Spirometry and single breath nitrogen washout were normal Monday morning before exposure to formaldehyde. A reduction in forced expiratory volume in 1 sec by an average of 0.2 L (P = .002), percent forced expiratory volume by 2% (P = .04), maximum midexpiratory flow by 0.3 L/sec (P = .04) and an increase in closing volume in percentage of vital capacity by 3.4% (P = .002) were seen after a day of work and exposure to formaldehyde, suggesting bronchoconstriction. Smokers and nonsmokers displayed similar changes in spirometry and nitrogen washout.

  19. Porous Nickel Oxide Film Sensor for Formaldehyde

    NASA Astrophysics Data System (ADS)

    Cindemir, U.; Topalian, Z.; Österlund, L.; Granqvist, C. G.; Niklasson, G. A.

    2014-11-01

    Formaldehyde is a volatile organic compound and a harmful indoor pollutant contributing to the "sick building syndrome". We used advanced gas deposition to fabricate highly porous nickel oxide (NiO) thin films for formaldehyde sensing. The films were deposited on Al2O3 substrates with prefabricated comb-structured electrodes and a resistive heater at the opposite face. The morphology and structure of the films were investigated with scanning electron microscopy and X-ray diffraction. Porosity was determined by nitrogen adsorption isotherms with the Brunauer-Emmett-Teller method. Gas sensing measurements were performed to demonstrate the resistive response of the sensors with respect to different concentrations of formaldehyde at 150 °C.

  20. N-acylethanolamines as novel alcohol dehydrogenase 3 substrates.

    PubMed

    Ivkovic, Milena; Dempsey, Daniel R; Handa, Sumit; Hilton, Joshua H; Lowe, Edward W; Merkler, David J

    2011-02-15

    N-acylethanolamines (NAEs) are members of the fatty acid amide family. The NAEs have been proposed to serve as metabolic precursors to N-acylglycines (NAGs). The sequential oxidation of the NAEs by an alcohol dehydrogenase and an aldehyde dehydrogenase would yield the N-acylglycinals and/or the NAGs. Alcohol dehydrogenase 3 (ADH3) is one enzyme that might catalyze this reaction. To define a potential role for ADH3 in NAE catabolism, we synthesized a set of NAEs and evaluated these as ADH3 substrates. NAEs were oxidized by ADH3, yielding the N-acylglycinals as the product. The (V/K)(app) values for the NAEs included here were low relative to cinnamyl alcohol. Our data show that the NAEs can serve as alcohol dehydrogenase substrates. PMID:21144815

  1. Self-Sufficient Formaldehyde-to-Methanol Conversion by Organometallic Formaldehyde Dismutase Mimic.

    PubMed

    van der Waals, Dominic; Heim, Leo E; Vallazza, Simona; Gedig, Christian; Deska, Jan; Prechtl, Martin H G

    2016-08-01

    The catalytic networks of methylotrophic organisms, featuring redox enzymes for the activation of one-carbon moieties, can serve as great inspiration in the development of novel homogeneously catalyzed pathways for the interconversion of C1 molecules at ambient conditions. An imidazolium-tagged arene-ruthenium complex was identified as an effective functional mimic of the bacterial formaldehyde dismutase, which provides a new and highly selective route for the conversion of formaldehyde to methanol in absence of any external reducing agents. Moreover, secondary amines are reductively methylated by the organometallic dismutase mimic in a redox self-sufficient manner with formaldehyde acting both as carbon source and reducing agent. PMID:27380865

  2. The effect of clothing care activities on textile formaldehyde content.

    PubMed

    Novick, Rachel M; Nelson, Mindy L; McKinley, Meg A; Anderson, Grace L; Keenan, James J

    2013-01-01

    Textiles are commonly treated with formaldehyde-based residues that may potentially induce allergic contact dermatitis in sensitive individuals. This study examined the initial formaldehyde content in clothing and resulting changes due to care activities. Twenty clothing articles were examined and 17 of them did not have detectable levels of formaldehyde. One shirt contained a formaldehyde concentration of 3172 ppm, and two pairs of pants had formaldehyde concentrations of 1391 ppm and 86 ppm. The two highest results represent formaldehyde levels that are up to 40-fold greater than international textile regulations. The two items with the greatest formaldehyde content were washed and dried in a manner similar to that used by consumers, including hand and machine washing in hot or cold water followed by air or machine drying. The washing and drying procedures reduced formaldehyde levels to between 26 and 72% of untreated controls. Differences in the temperature or type of washing and drying did not result in a clear trend in the subsequent formaldehyde content. In addition, samples were hot ironed, which did not affect the formaldehyde content as significantly. Understanding the formaldehyde content in clothing and its potential reduction through care activities may be useful for manufacturers and formaldehyde-sensitive individuals. PMID:24053365

  3. STATUS OF IODINE IN FORMALDEHYDE-PRESERVED MILK - REVISITED

    EPA Science Inventory

    The effect of formaldehyde as a preservative for milk prior to radiochemical analysis for 131I was studied. Results suggest that the formaldehyde concentration is critical and that at low formaldehyde concentrations (<0.5 M) significant protein binding of iodine occurs. Various a...

  4. 24 CFR 3280.309 - Health Notice on formaldehyde emissions.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 5 2014-04-01 2014-04-01 false Health Notice on formaldehyde... Construction Requirements § 3280.309 Health Notice on formaldehyde emissions. (a) Each manufactured home shall have a Health Notice on formaldehyde emissions prominently displayed in a temporary manner in...

  5. Developing a Reference Material for Formaldehyde Emissions Testing; Final Report

    EPA Science Inventory

    Exposure to formaldehyde has been shown to produce broad and potentially severe adverse human health effects. With ubiquitous formaldehyde sources in the indoor environment, formaldehyde concentrations in indoor air are usually higher than outdoors, ranging from 10 to 4000 μg/m3....

  6. Chemical Characterization of Phenol/Formaldehyde Resins

    NASA Technical Reports Server (NTRS)

    Brayden, T. H.

    1986-01-01

    Report discusses tests of commercial phenol/formaldehyde resins to establish relationships among composition before use, behavior during curing, and strength after curing. Resin used in carbon/carbon laminates. In curing process, two molecules of phenol joined together in sequence of reactions involving molecule of formaldehyde. Last step of sequence, molecule of water released. Sequence repeats until one of ingredients used up, leaving solidified thermoset plastic. Issues to be resolved: number and relative abundances of ingredients, presence of certain chemical groups, heat-producing ability of resin, and range of molecular weights present.

  7. Expression of Alcohol Dehydrogenase 3 in Tissue and Cultured Cells from Human Oral Mucosa

    PubMed Central

    Hedberg, Jesper J.; Höög, Jan-Olov; Nilsson, Jan A.; Xi, Zheng; Elfwing, Åsa; Grafström, Roland C.

    2000-01-01

    Because formaldehyde exposure has been shown to induce pathological changes in human oral mucosa, eg, micronuclei, the potential enzymatic defense by alcohol dehydrogenase 3 (ADH3)/glutathione-dependent formaldehyde dehydrogenase was characterized in oral tissue specimens and cell lines using RNA hybridization and immunological methods as well as enzyme activity measurements. ADH3 mRNA was expressed in basal and parabasal cell layers of oral epithelium, whereas the protein was detected throughout the cell layers. ADH3 mRNA and protein were further detected in homogenates of oral tissue and various oral cell cultures, including, normal, SV40T antigen-immortalized, and tumor keratinocyte lines. Inhibition of the growth of normal keratinocytes by maintenance at confluency significantly decreased the amount of ADH3 mRNA, a transcript with a determined half-life of 7 hours. In contrast, decay of ADH3 protein was not observed throughout a 4-day period in normal keratinocytes. In samples from both tissue and cells, the ADH3 protein content correlated to oxidizing activity for the ADH3-specific substrate S-hydroxymethylglutathione. The composite analyses associates ADH3 mRNA primarily to proliferative keratinocytes where it exhibits a comparatively short half-life. In contrast, the ADH3 protein is extremely stable, and consequently is retained during the keratinocyte life span in oral mucosa. Finally, substantial capacity for formaldehyde detoxification is shown from quantitative assessments of alcohol- and aldehyde-oxidizing activities including Km determinations, indicating that ADH3 is the major enzyme involved in formaldehyde oxidation in oral mucosa. PMID:11073833

  8. Unusual formaldehyde-induced hypersensitivity in two schoolgirls

    SciTech Connect

    Gammage, R.B. ); Hanna, W.T.; Painter, P.B. )

    1990-01-01

    Two schoolgirls developed a syndrome resembling Henoch-Schonlein purpura while attending a recently opened school insulated with urea-formaldehyde foam (UFFI). Skin rashes and swellings were accompanied by bizarre, blue-green discoloration of the skin. Subsequent investigations by county, state and federal authorities, and low measured concentrations of formaldehyde, prompted initial conclusions that in-school formaldehyde exposures were not responsible for the girls' problems. Subsequent controlled exposures to UFFI and formaldehyde while in hospital elicited the whole cascade of symptoms. The chronology of the onset and amplification of systems make it probable that the formaldehyde exposures precipitating the girls' hypersensitivity, occurred in the school. 3 refs.

  9. Airborne In-Situ Measurements of Formaldehyde over California: First Results from the Compact Formaldehyde Fluorescence Experiment (COFFEE) Instrument

    NASA Technical Reports Server (NTRS)

    Marrero, Josette; St. Clair, Jason; Yates, Emma L.; Gore, Warren; Swanson, Andrew K.; Iraci, Laura T.; Hanisco, Thomas F.

    2016-01-01

    Formaldehyde (HCHO) is one of the most abundant oxygenated volatile organic compounds (VOCs) in the atmosphere, playing a role multiple atmospheric processes. Measurements of HCHO can be used to help quantify convective transport, the abundance of VOCs, and ozone production in urban environments. The Compact Formaldehyde FluorescencE Experiment (COFFEE) instrument uses Non-Resonant Laser Induced Fluorescence (NR-LIF) to detect trace concentrations of HCHO as part of the Alpha Jet Atmospheric eXperiment (AJAX) payload. Developed at NASA GSFC, COFFEE is a small, low maintenance instrument with a sensitivity of 100 pptv and a quick response time (1 sec). The COFFEE instrument has been customized to fit in an external wing pod on the Alpha Jet aircraft based at NASA ARC. The instrument can operate over a broad range of altitudes, from boundary layer to lower stratosphere, making it well suited for the Alpha Jet, which can access altitudes from the surface up to 40,000 ft. Results of the first COFFEE science flights preformed over the California's Central Valley will be presented. Boundary layer measurements and vertical profiles in the tropospheric column will both be included. This region is of particular interest, due to its elevated levels of HCHO, revealed in satellite images, as well as its high ozone concentrations. In addition to HCHO, the AJAX payload includes measurements of atmospheric ozone, methane, and carbon dioxide. Formaldehyde is one of the few urban pollutants that can be measured from space. Plans to compare in-situ COFFEE data with satellite-based HCHO observations such as those from OMI (Aura) and OMPS (SuomiNPP) will also be presented.

  10. Airborne In-Situ Measurements of Formaldehyde Over California: First Results from the Compact Formaldehyde Fluorescence Experiment (COFFEE) Instrument

    NASA Technical Reports Server (NTRS)

    Marrero, Josette Elizabeth; Saint Clair, Jason; Yates, Emma L.; Gore, Warren; Swanson, Andrew K.; Iraci, Laura T.; Hanisco, Thomas F.

    2016-01-01

    Formaldehyde (HCHO) is one of the most abundant oxygenated volatile organic compounds (VOCs) in the atmosphere, playing a role multiple atmospheric processes. Measurements of HCHO can be used to help quantify convective transport, the abundance of VOCs, and ozone production in urban environments. The Compact Formaldehyde FluorescencE Experiment (COFFEE) instrument uses Non-Resonant Laser Induced Fluorescence (NR-LIF) to detect trace concentrations of HCHO as part of the Alpha Jet Atmospheric eXperiment (AJAX) payload. Developed at NASA GSFC, COFFEE is a small, low maintenance instrument with a sensitivity of 100 pptv and a quick response time (1 sec). The COFFEE instrument has been customized to fit in an external wing pod on the Alpha Jet aircraft based at NASA ARC. The instrument can operate over a broad range of altitudes, from boundary layer to lower stratosphere, making it well suited for the Alpha Jet, which can access altitudes from the surface up to 40,000 ft. Results of the first COFFEE science flights preformed over the California's Central Valley will be presented. Boundary layer measurements and vertical profiles in the tropospheric column will both be included. This region is of particular interest, due to its elevated levels of HCHO, revealed in satellite images, as well as its high ozone concentrations. In addition to HCHO, the AJAX payload includes measurements of atmospheric ozone, methane, and carbon dioxide. Formaldehyde is one of the few urban pollutants that can be measured from space. Plans to compare in-situ COFFEE data with satellite-based HCHO observations such as those from OMI (Aura) and OMPS (SuomiNPP) will also be presented.

  11. 29 CFR 1926.1148 - Formaldehyde.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 8 2013-07-01 2013-07-01 false Formaldehyde. 1926.1148 Section 1926.1148 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Toxic and Hazardous Substances § 1926.1148...

  12. 29 CFR 1926.1148 - Formaldehyde.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Formaldehyde. 1926.1148 Section 1926.1148 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Toxic and Hazardous Substances § 1926.1148...

  13. 29 CFR 1926.1148 - Formaldehyde.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 8 2014-07-01 2014-07-01 false Formaldehyde. 1926.1148 Section 1926.1148 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Toxic and Hazardous Substances § 1926.1148...

  14. 29 CFR 1926.1148 - Formaldehyde.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 8 2012-07-01 2012-07-01 false Formaldehyde. 1926.1148 Section 1926.1148 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Toxic and Hazardous Substances § 1926.1148...

  15. A passive sampler for airborne formaldehyde

    NASA Astrophysics Data System (ADS)

    Grosjean, Daniel; Williams, Edwin L.

    A simple, inexpensive passive sampler is described that is capable of reliable measurements of formaldehyde at the parts per billion (ppb) levels relevant to indoor and outdoor air quality. The passive sampler consists of a modified dual filter holder in which the upper stage serves as the diffusion barrier, the lower stage includes a 2,4-dinitrophenylhydrazine (DNPH)-coated filter which collects formaldehyde, and the space between the two stages serve as the diffusion gap. The measured sampling rate, 18.8 ± 1.8 ml min -1, was determined in experiments involving sampling of ppb levels of formaldehyde with the passive sampler and with DNPH-coated C 18 cartridges and agrees well with the value of 19.4 ± 2.0 ml min -1 calculated from theory. The measured sampling rate was independent of formaldehyde concentration (16-156 ppb) and sampling duration (1.5-72 h). The precision of the measurements for colocated passive samplers averaged 8.6% in purified and indoor air (office and museums) and 10.2% in photochemically polluted outdoor air. With a 1.2-μm pore size Teflon filter as the diffusion barrier, the detection limit is 32 ppb h, e.g. 4 ppb in an 8-h sample, 1.3 ppb in a 24-h sample, and so on. Perceived advantages and limitations of the sampler are discussed including flexibility, cost effectiveness and possible negative bias at high ambient levels of ozone.

  16. CHRONIC RESPIRATORY EFFECTS OF INDOOR FORMALDEHYDE EXPOSURE

    EPA Science Inventory

    The relation of chronic respiratory symptoms and pulmonary function to formaldehyde (HCHO) in homes was studied in a sample of 298 children (6 - 15 years of age) and 613 adults. CHO measurements were made with passive samplers two one-week periods. ata on chronic cough and phlegm...

  17. Gypsum Wallboard as a sink for formaldehyde

    EPA Science Inventory

    Formaldehyde (HCHO) has been of special concern as an indoor air pollutant because of its presence in a wide range of consumer products and its adverse health effects. Materials acting as HCHO sinks, such as painted gypsum wallboard, can become emission sources. However, adsorpti...

  18. Electrospinning formaldehyde cross-linked zein solutions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to develop zein fibers with improved physical properties and solvent resistance, formaldehyde was used as the cross-linking reagent before spinning. The cross-linking reaction was carried out in either acetic acid or ethanolic-HCl where the amount of cross-linking reagent was between 1 and...

  19. 29 CFR 1926.1148 - Formaldehyde.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Formaldehyde. 1926.1148 Section 1926.1148 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Toxic and Hazardous Substances § 1926.1148...

  20. Edible carbohydrates from formaldehyde in a spacecraft

    NASA Technical Reports Server (NTRS)

    Weiss, A. H.

    1975-01-01

    The autocatalytic nature of the base catalyzed condensation of formaldehyde to formose sugars is eliminated by using as a cocatalyst, an aldose, or ketose having an alpha-hydrogen. This is more strongly complexed by base than is formaldehyde and the cocatalyst and sugar products accumulate as catalyst complexes instead of formaldehyde. Because of the presence of alpha-hydrogen atoms in cocatalysts and formose sugars, their removal by cross Cannizzaro reaction of complexed sugars does not occur, so the formose reaction behaves autocatalytically due to this accumulation. It is believed that a given catalytic formose complex is not a discrete complexed sugar, but rather, a scrambled dynamic mixture of sugars having weakened structures. The sugar complexes derive from a common salt-like formaldehyde complex, which, because of the absence of alpha-hydrogen, has a greater tendency to undergo Cannizzaro reaction, rather than formose condensation. Because of this, the Cannizzaro reaction can proceed without measurable formose condensation. The reverse is not possible.

  1. Dihydrodiol dehydrogenase and polycyclic aromatic hydrocarbon metabolism

    SciTech Connect

    Smithgall, T.E.

    1986-01-01

    Carcinogenic activation of polycyclic aromatic hydrocarbons by microsomal monoxygenases proceeds through trans-dihydrodiol metabolites to diol-epoxide ultimate carcinogens. This thesis directly investigated the role of dihydrodiol dehydrogenase, a cytosolic NAD(P)-linked oxidoreductase, in the detoxification of polycyclic aromatic trans-dihydrodiols. A wide variety of non-K-region trans-dihydrodiols were synthesized and shown to be substrates for the homogeneous rat liver dehydrogenase, including several potent proximate carcinogens derived from 7,12-dimethylbenz(a)anthracene, 5-methylchrysene, and benzo(a)pyrene. Since microsomal activation of polycyclic aromatic hydrocarbons is highly stereospecific, the stereochemical course of enzymatic trans-dihydrodiol oxidation was monitored using circular dichroism spectropolarimetry. The major product formed from the dehydrogenase-catalyzed oxidation of the trans-1,2-dihydrodiol of naphthalene was characterized using UV, IR, NMR, and mass spectroscopy, and appears to be 4-hydroxy-1,2-naphthoquinone. Mass spectral analysis suggests that an analogous hydroxylated o-quinone is formed as the major product of benzo(a)pyrene-7,8-dihydrodiol oxidation. Enzymatic oxidation of trans-dihydrodiols was shown to be potently inhibited by all of the major classes of the nonsteroidal antiinflammatory drugs. Enhancement of trans-dihydrodiol proximate carcinogen oxidation may protect against possible adverse effects of the aspirin-like drugs, and help maintain the balance between activation and detoxification of polycyclic aromatic hydrocarbons.

  2. Lactate dehydrogenase-elevating virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This book chapter describes the taxonomic classification of Lactate dehydrogenase-elevating virus (LDV). Included are: host, genome, classification, morphology, physicochemical and physical properties, nucleic acid, proteins, lipids, carbohydrates, geographic range, phylogenetic properties, biologic...

  3. Toxic effects of formaldehyde on the urinary system

    PubMed Central

    İnci, Mehmet; Zararsız, İsmail; Davarcı, Mürsel; Görür, Sadık

    2013-01-01

    Formaldehyde is a chemical substance with a pungent odor that is highly soluble in water and occurs naturally in organisms. Formaldehyde, when taken into organisms, is metabolized into formic acid in the liver and erythrocytes and is then excreted, either with the urine and feces or via the respiratory system. Form-aldehyde is widely used in the industrial and medical fields, and employees in these sectors are frequently exposed to it. Anatomists and medical students are affected by formaldehyde gas during dissection lessons. Because full protection from formaldehyde is impossible for employees in industrial plants using this chemical and for workers in laboratory conditions, several measures can be implemented to prevent and/or reduce the toxic effects of formaldehyde. In this review, we aimed to identify the toxic effects of formaldehyde on the urinary system. PMID:26328078

  4. A role for tungsten in the biology of Campylobacter jejuni: tungstate stimulates formate dehydrogenase activity and is transported via an ultra-high affinity ABC system distinct from the molybdate transporter.

    PubMed

    Smart, Jonathan P; Cliff, Matthew J; Kelly, David J

    2009-11-01

    The food-borne pathogen Campylobacter jejuni possesses no known tungstoenzymes, yet encodes two ABC transporters (Cj0300-0303 and Cj1538-1540) homologous to bacterial molybdate (ModABC) uptake systems and the tungstate transporter (TupABC) of Eubacterium acidaminophilum respectively. The actual substrates and physiological role of these transporters were investigated. Tryptophan fluorescence spectroscopy and isothermal titration calorimetry of the purified periplasmic binding proteins of each system revealed that while Cj0303 is unable to discriminate between molybdate and tungstate (K(D) values for both ligands of 4-8 nM), Cj1540 binds tungstate with a K(D) of 1.0 +/- 0.2 pM; 50 000-fold more tightly than molybdate. Induction-coupled plasma mass spectroscopy of single and double mutants showed that this large difference in affinity is reflected in a lower cellular tungsten content in a cj1540 (tupA) mutant compared with a cj0303c (modA) mutant. Surprisingly, formate dehydrogenase (FDH) activity was decreased approximately 50% in the tupA strain, and supplementation of the growth medium with tungstate significantly increased FDH activity in the wild type, while inhibiting known molybdoenzymes. Our data suggest that C. jejuni possesses a specific, ultra-high affinity tungstate transporter that supplies tungsten for incorporation into FDH. Furthermore, possession of two MoeA paralogues may explain the formation of both molybdopterin and tungstopterin in this bacterium. PMID:19818021

  5. Proline dehydrogenase (oxidase) in cancer.

    PubMed

    Liu, Wei; Phang, James M

    2012-01-01

    Proline dehydrogenase (oxidase, PRODH/POX), the first enzyme in the proline degradative pathway, plays a special role in tumorigenesis and tumor development. Proline metabolism catalyzed by PRODH/POX is closely linked with the tricarboxylic acid (TCA) cycle and urea cycle. The proline cycle formed by the interconversion of proline and Δ(1) -pyrroline-5-carboxylate (P5C) between mitochondria and cytosol interlocks with pentose phosphate pathway. Importantly, by catalyzing proline to P5C, PRODH/POX donates electrons into the electron transport chain to generate ROS or ATP. In earlier studies, we found that PRODH/POX functions as a tumor suppressor to initiate apoptosis, inhibit tumor growth, and block the cell cycle, all by ROS signaling. It also suppresses hypoxia inducible factor signaling by increasing α-ketoglutarate. During tumor progression, PRODH/POX is under the control of various tumor-associated factors, such as tumor suppressor p53, inflammatory factor peroxisome proliferator-activated receptor gamma (PPARγ), onco-miRNA miR-23b*, and oncogenic transcription factor c-MYC. Recent studies revealed the two-sided features of PRODH/POX-mediated regulation. Under metabolic stress such as oxygen and glucose deprivation, PRODH/POX can be induced to serve as a tumor survival factor through ATP production or ROS-induced autophagy. The paradoxical roles of PRODH/POX can be understood considering the temporal and spatial context of the tumor. Further studies will provide additional insights into this protein and on its metabolic effects in tumors, which may lead to new therapeutic strategies. PMID:22886911

  6. Dihydrolipoamide dehydrogenase from halophilic archaebacteria: purification and properties of the enzyme from halobacterium halobium

    SciTech Connect

    Danson, J.J.; McQuattie, A.; Stevenson, K.J.

    1986-07-01

    Halophilic archaebacteria possess dihydrolipoamide dehydrogenase activity but apparently lack the 2-oxoacid dehydrogenase multienzyme complexes of which it is usually an integral component. In this paper, the purification of dihydrolipoamide dehydrogenase from Halobacterium halobium is reported. The enzyme is a dimer with a polypeptide chain M/sub r/ of 58,000 (+/-3000). The amino acid composition of the enzyme is compared with those of the eubacterial and eukaryotic dihydrolipoamide dehydrogenases, and evidence is presented to suggest that the N-terminal amino acid of the H. halobium enzyme is blocked. Chemical modification with the trivalent arsenical reagent (p-aminophenyl)dichloroarsine indicates the involvement of a reversibly reducible disulfide bond in the enzyme's catalytic mechanism. The possible metabolic role of this dihydrolipoamide dehydrogenase in the absence of 2-oxoacid dehydrogenase complexes is discussed.

  7. The Alcohol Dehydrogenase Gene Family in Melon (Cucumis melo L.): Bioinformatic Analysis and Expression Patterns

    PubMed Central

    Jin, Yazhong; Zhang, Chong; Liu, Wei; Tang, Yufan; Qi, Hongyan; Chen, Hao; Cao, Songxiao

    2016-01-01

    Alcohol dehydrogenases (ADH), encoded by multigene family in plants, play a critical role in plant growth, development, adaptation, fruit ripening and aroma production. Thirteen ADH genes were identified in melon genome, including 12 ADHs and one formaldehyde dehydrogenease (FDH), designated CmADH1-12 and CmFDH1, in which CmADH1 and CmADH2 have been isolated in Cantaloupe. ADH genes shared a lower identity with each other at the protein level and had different intron-exon structure at nucleotide level. No typical signal peptides were found in all CmADHs, and CmADH proteins might locate in the cytoplasm. The phylogenetic tree revealed that 13 ADH genes were divided into three groups respectively, namely long-, medium-, and short-chain ADH subfamily, and CmADH1,3-11, which belongs to the medium-chain ADH subfamily, fell into six medium-chain ADH subgroups. CmADH12 may belong to the long-chain ADH subfamily, while CmFDH1 may be a Class III ADH and serve as an ancestral ADH in melon. Expression profiling revealed that CmADH1, CmADH2, CmADH10 and CmFDH1 were moderately or strongly expressed in different vegetative tissues and fruit at medium and late developmental stages, while CmADH8 and CmADH12 were highly expressed in fruit after 20 days. CmADH3 showed preferential expression in young tissues. CmADH4 only had slight expression in root. Promoter analysis revealed several motifs of CmADH genes involved in the gene expression modulated by various hormones, and the response pattern of CmADH genes to ABA, IAA and ethylene were different. These CmADHs were divided into ethylene-sensitive and –insensitive groups, and the functions of CmADHs were discussed. PMID:27242871

  8. Effect of a static magnetic field on formaldehyde biodegradation in wastewater by activated sludge.

    PubMed

    Łebkowska, Maria; Rutkowska-Narożniak, Anna; Pajor, Elżbieta; Pochanke, Zbigniew

    2011-10-01

    The aim of this study was to determine the impact of a static magnetic field (MF) of 7 mT on formaldehyde (FA) biodegradation by activated sludge in synthetic wastewater. The MF had a positive effect on activated sludge biomass growth and dehydrogenase activity. The influence of the MF on the degradation process was observed with a FA concentration of 2400-2880 mg/l. Decreases in FA concentration and chemical oxygen demand (COD) were greater, by 30% and 26% respectively, than those in the control sample. At initial FA concentrations in raw wastewater of 2400 and 2880 mg/l, a decrease in the wastewater biodegradation efficiency was observed. This resulted in an increase of the ecotoxicity of the effluent to Daphnia magna. The value of the sludge biotic index (SBI) was dependent on the FA concentration in raw wastewater and the induction of the MF. PMID:21824771

  9. The microcapsule-type formaldehyde scavenger: the preparation and the application in urea-formaldehyde adhesives.

    PubMed

    Duan, Hongyun; Qiu, Teng; Guo, Longhai; Ye, Jun; Li, Xiaoyu

    2015-08-15

    The limitation and regulation of formaldehyde emissions (FE) now shows great importance in wood-based materials such as plywood and particle board manufactured for building and furnishing materials. The widely used formaldehyde-based adhesives are one of the main sources of FE from the wood products. In this work, a new kind of long-term effective formaldehyde scavenger in the microcapsule form was prepared by using an intra-liquid desiccation method. The characterizations of the capsule (UC) were performed including the morphologies, the yields, the loading efficiency as well as its sustained-release of urea in aqueous conditions. The prepared UC could be integrated in urea-formaldehyde resins by simply physical blending, and the mixtures were available to be applied as the adhesives for the manufacture of plywood. The bonding strength (BS) and the FE of the bonded plywood in both short (3h) and long (12 week) period were evaluated in detail. It was found that the FE profile of the plywood behaved following a duple exponential law within 12 week. The addition of UC in the adhesive can effectively depress the FE of the plywood not only in a short period after preparation but also in a long-term period during its practical application. The slow released urea would continuously suppress the emission of toxic formaldehyde in a sustained manner without obviously deteriorating on the BS of the adhesives. PMID:25855565

  10. Michael hydratase alcohol dehydrogenase or just alcohol dehydrogenase?

    PubMed Central

    2014-01-01

    The Michael hydratase – alcohol dehydrogenase (MhyADH) from Alicycliphilus denitrificans was previously identified as a bi-functional enzyme performing a hydration of α,β-unsaturated ketones and subsequent oxidation of the formed alcohols. The investigations of the bi-functionality were based on a spectrophotometric assay and an activity staining in a native gel of the dehydrogenase. New insights in the recently discovered organocatalytic Michael addition of water led to the conclusion that the previously performed experiments to identify MhyADH as a bi-functional enzyme and their results need to be reconsidered and the reliability of the methodology used needs to be critically evaluated. PMID:24949265

  11. Effect of Relative Humidity on Formaldehyde Decontamination

    PubMed Central

    Spiner, David R.; Hoffman, Robert K.

    1971-01-01

    Death rate studies were conducted to determine the effect of varying the concentration, humidity, and type of surface on the sporicidal activity of formaldehyde gas. Washed and unwashed spores were similarly exposed to detect the influence of residual nutrient growth medium upon the rate of kill. The results indicated that the sporicidal activity of formaldehyde gas varies directly with its concentration. Relative humidities (RH) over 50% proved essential for sterility. Spores on a porous surface (cotton cloth) were more readily killed at lower RH than those on a nonporous surface (glass). The reverse occurred at very high RH. At 75% RH, the unwashed spores on glass were killed faster than the washed spores. Images PMID:5002898

  12. Formaldehyde in envelopes of interstellar dark clouds

    NASA Technical Reports Server (NTRS)

    Federman, S. R.; Allen, M.

    1991-01-01

    Observed formaldehyde column densities of 1 x 10 to the 12th - 3 x 10 to the 13th/sq cm in cloud envelopes along lines of sight with A(V) = 1-4 mag can not be explained with the current understanding of interstellar gas phase chemistry. However, these column densities can be reproduced by a simple time-dependent model in which H2CO is supplied to the gas phase by the erosion of icy grain mantles. The release of H2CO from the grain mantles must occur on time scales comparable to the time scales for mixing from the cloud interior to the cloud envelope. Thus, in low-density regions of clouds, it appears that formaldehyde is the second molecule whose gas phase source is primarily ejection from grains. This simple model suggests understanding gas phase steady state in clouds on macroscopic, rather than microscopic, spatial scales.

  13. The different roles of molecular classification according to upfront autologous stem cell transplantation in advanced-stage diffuse large B cell lymphoma patients with elevated serum lactate dehydrogenase.

    PubMed

    Kim, Yu Ri; Kim, Soo-Jeong; Cheong, June-Won; Yang, Deok-Hwan; Lee, Hyewon; Eom, Hyeon-Seok; Sung, Yong Oh; Kim, Hyo Jung; Kang, Hye Jin; Lee, Won-Sik; Park, Yong; Yang, Woo-Ick; Min, Yoo Hong; Kim, Jin Seok

    2016-09-01

    The non-germinal center B cell (non-GCB) subtype of diffuse large B cell lymphoma (DLBCL) is more related to poor prognosis than the GCB subtype. To investigate the role of molecular classification according to upfront autologous hematopoietic stem cell transplantation (ASCT), we retrospectively evaluated 219 newly diagnosed high-risk DLBCL patients. Eighty-one patients were in the ASCT group, and 138 patients were in the non-ASCT group. The ASCT group yielded significantly better overall survival (OS) and progression-free survival (PFS) than the non-ASCT group (p = 0.038 and p = 0.007), and patients with the non-GCB subtype were more related to inferior PFS than those with the GCB subtype (p = 0.020). After performing age-matching by using propensity scores, upfront ASCT continued to show better OS and PFS than non-ASCT (p = 0.046 and p = 0.026). In the non-ASCT group, the non-GCB subtype showed worse OS and PFS than the GCB subtype (p = 0.039 and p = 0.007). Patients who achieved complete response showed differences in OS and PFS according to molecular subtype (p = 0.007 and p = 0.002). In the ASCT group, there were no significant differences in OS and PFS according to molecular classification (p = 0.277 and p = 0.892). In conclusion, non-GCB subtype DLBCL patients showed poor OS and PFS in the non-ASCT group while they did not show clinical significance in the ASCT group. This suggests the possibility that upfront ASCT may improve the poor prognosis of non-GCB subtype in high-risk DLBCL. PMID:27324387

  14. Room-Temperature Oxidation of Formaldehyde by Layered Manganese Oxide: Effect of Water.

    PubMed

    Wang, Jinlong; Zhang, Pengyi; Li, Jinge; Jiang, Chuanjia; Yunus, Rizwangul; Kim, Jeonghyun

    2015-10-20

    Layered manganese oxide, i.e., birnessite was prepared via the reaction of potassium permanganate with ammonium oxalate. The water content in the birnessite was adjusted by drying/calcining the samples at various temperatures (30 °C, 100 °C, 200 °C, 300 °C, and 500 °C). Thermogravimetry-mass spectroscopy showed three types of water released from birnessite, which can be ascribed to physically adsorbed H2O, interlayer H2O and hydroxyl, respectively. The activity of birnessite for formaldehyde oxidation was positively associated with its water content, i.e., the higher the water content, the better activity it has. In-situ DRIFTS and step scanning XRD analysis indicate that adsorbed formaldehyde, which is promoted by bonded water via hydrogen bonding, is transformed into formate and carbonate with the consumption of hydroxyl and bonded water. Both bonded water and water in air can compensate the consumed hydroxyl groups to sustain the mineralization of formaldehyde at room temperature. In addition, water in air stimulates the desorption of carbonate via water competitive adsorption, and accordingly the birnessite recovers its activity. This investigation elucidated the role of water in oxidizing formaldehyde by layered manganese oxides at room temperature, which may be helpful for the development of more efficient materials. PMID:26426569

  15. Physiological Studies of Methane- and Methanol-Oxidizing Bacteria: Comparison of a Primary Alcohol Dehydrogenase from Methylococcus capsulatus (Texas Strain) and Pseudomonas Species M27

    PubMed Central

    Patel, R. N.; Bose, H. R.; Mandy, W. J.; Hoare, D. S.

    1972-01-01

    A primary alcohol dehydrogenase has been purified from Methylococcus capsulatus (Texas strain). The purified enzyme catalyzes the oxidation of methanol and formaldehyde to formate; other primary alcohols are oxidized to their corresponding aldehydes. Ammonium ions are required for enzyme activity. The enzyme has a molecular weight of 120,000 daltons and consists of two 62,000 molecular-weight subunits which dissociate at acidic pH. The enzyme is similar to an alcohol dehydrogenase enzyme isolated from Pseudomonas sp. M27. Images PMID:5022170

  16. Stringency of substrate specificity of Escherichia coli malate dehydrogenase.

    SciTech Connect

    Boernke, W. E.; Millard, C. S.; Stevens, P. W.; Kakar, S. N.; Stevens, F. J.; Donnelly, M. I.; Nebraska Wesleyan Univ.

    1995-09-10

    Malate dehydrogenase and lactate dehydrogenase are members of the structurally and functionally homologous family of 2-ketoacid dehydrogenases. Both enzymes display high specificity for their respective keto substrates, oxaloacetate and pyruvate. Closer analysis of their specificity, however, reveals that the specificity of malate dehydrogenase is much stricter and less malleable than that of lactate dehydrogenase. Site-specific mutagenesis of the two enzymes in an attempt to reverse their specificity has met with contrary results. Conversion of a specific active-site glutamine to arginine in lactate dehydrogenase from Bacillus stearothermophilus generated an enzyme that displayed activity toward oxaloacetate equal to that of the native enzyme toward pyruvate (H. M. Wilks et al. (1988) Science 242, 1541-1544). We have constructed a series of mutants in the mobile, active site loop of the Escherichia coli malate dehydrogenase that incorporate the complementary change, conversion of arginine 81 to glutamine, to evaluate the role of charge distribution and conformational flexibility within this loop in defining the substrate specificity of these enzymes. Mutants incorporating the change R81Q all had reversed specificity, displaying much higher activity toward pyruvate than to the natural substrate, oxaloacetate. In contrast to the mutated lactate dehydrogenase, these reversed-specificity mutants were much less active than the native enzyme. Secondary mutations within the loop of the E. coli enzyme (A80N, A80P, A80P/M85E/D86T) had either no or only moderately beneficial effects on the activity of the mutant enzyme toward pyruvate. The mutation A80P, which can be expected to reduce the overall flexibility of the loop, modestly improved activity toward pyruvate. The possible physiological relevance of the stringent specificity of malate dehydrogenase was investigated. In normal strains of E. coli, fermentative metabolism was not affected by expression of the mutant

  17. Type 5 17β-Hydroxysteroid Dehydrogenase/Prostaglandin F Synthase (AKR1C3): Role In Breast Cancer and Inhibition by Nonsteroidal Antiinflammatory Drug Analogs

    PubMed Central

    Byrns, Michael C.; Penning, Trevor M.

    2011-01-01

    specific inhibitors of AKR1C3 will help validate its role in the proliferation of breast cancer cells. PMID:19010312

  18. Problems associated with the use of urea-formaldehyde foam for residential insulation. Part II. The effects of temperature and humidity on free formaldehyde, extractable formaldehyde, formaldehyde emission, and physical characteristics of the foam

    SciTech Connect

    Schutte, W.C.; Cole, R.S.; Frank, C.W.; Long, K.R.

    1981-02-01

    Results of testing with two products of urea-formaldehyde based foams are described. Results of three products have previously been reported. Methods for detection and quantitative determination of formaldehyde, design of the experimental chambers, and the procedures are described. Samples of Product D were monitored for about 29 days and samples of Product E were monitored for 60 days in chambers and results are tabulated for formaldehyde emission. Additional tests performed on the two products are: extractable formaldehyde (high and low temperature conditions); free formaldehyde (high and low temperature conditions); comparison of free formaldehyde concentration; density (high and low temperature conditions); shrinkage (high and low temperature conditions). Control panels were constructed to simulate a wall in a home and observations were made and compared with results of the experimental products.

  19. Formaldehyde exposure affects growth and metabolism of common bean

    SciTech Connect

    Mutters, R.G.; Madore, M. ); Bytnerowicz, A. )

    1993-01-01

    Recent state and federal directives have slated a substantial increase in the use of methanol as an alternative to gasoline in both fleet and private vehicles in the coming decade. The incomplete combustion of methanol produces formaldehyde vapor, and catalytic converter technology that completely oxidizes formaldehyde has yet to be developed. The approach of this study was to use a range of methanol concentrations encompassing levels currently found or that may occur in the future in the ambient air of some heavily polluted areas to test the potential phytotoxicity of formaldehyde. The study had the following objectives: (1) design and build a formaldehyde vapor generator with sufficient capacity for long-term plant fumigations; (2) determine growth response of common bean to formaldehyde; (3) evaluate physiological and biochemical changes of bean plants associated with formaldehyde exposures. 20 refs., 2 figs., 2 tabs.

  20. Determination of Formaldehyde in Cigarette Smoke

    NASA Astrophysics Data System (ADS)

    Wong, Jon W.; Ngim, Kenley K.; Eiserich, Jason P.; Yeo, Helen C. H.; Shibamoto, Takayuki; Mabury, Scott A.

    1997-09-01

    Formaldehdye is considered a hazardous air pollutant with numerous sources that include environmental tobacco smoke (ETS). With the increasing interest regarding ETS and public health the measurement of formaldehyde readily lends itself to a laboratory experiment comparing methods of analysis. This experiment involves the collection, derivatization, extraction, and analysis of formaldehyde from cigarette smoke using two methods. Formaldehyde is extracted from smoke and derivitized with a solution of 2,4-DNPH with subsequent cleanup by solid-phase extraction and analysis of the hydrazone by HPLC with UV detection; additionally a solution of cysteamine yields the corresponding thiazolidine derivative that is liquid/liquid extracted and subsequently analyzed by either GC with NPD or FPD (sulfur mode). Reasonable agreement among the methods was obtained by lab demonstrators with spike recoveries yielding 94.7 + 6.8 (n=5) and 89.2 (n = 4) % for NPD and FPD, respectively while HPLC spiked recoveries were 83.6 + 3.2 (n = 5) %; mean class spike recoveries ranged from 80-100%. Student results (in mg/cigarette) from smoke samples were similar to literature values with 163.2 + 69.2 (n = 7) and 149.4 (n = 7) % for NPD and FPD, respectively; the HPLC result was significantly lower at 45.1 + 23.7(n = 7) with losses presumably due to hydrazone precipitating from the smoke extracted solution. Students particularly benefited from the "real world" nature of the analysis and the experience evaluating disparate methods of determining a common analyte.

  1. Health and environmental effects profile for formaldehyde

    SciTech Connect

    Not Available

    1985-10-01

    The Health and Environmental Effects Profile for formaldehyde was prepared by the Office of Health and Environmental Assessment, Environmental Criteria and Assessment Office, Cincinnati, OH for the Office of Solid Waste and Emergency Response to support listings of hazardous constituents of a wide range of waste streams under Section 3001 of the Resource Conservation and Recovery Act (RCRA) and to provide health-related limits for emergency actions under Section 101 of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA). Both published literature and information obtained from Agency program office files were evaluated as they pertained to potential human health, aquatic life, and environmental effects of hazardous-waste constituents. Quantitative estimates are presented, provided sufficient data are available. Existing data are insufficient to determine an Acceptable Daily Intake (ADI) or a carcinogenic potency factor for formaldehyde. The Reportable Quantity (RQ) value of 1, 10, 100, 1000, or 5000 pounds is used to determine the quantity of a hazardous substance for which notification is required in the event of a release as specified by CERCLA based on chronic toxicity. The RQ value for formaldehyde is 10.

  2. Formaldehyde production promoted by rat nasal cytochrome P-450-dependent monooxygenases with nasal decongestants, essences, solvents, air pollutants, nicotine, and cocaine as substrates

    SciTech Connect

    Dahl, A.R.; Hadley, W.M.

    1983-02-01

    To identify compounds which might be metabolized to formaldehyde in the nasal cavity, 32 potential substrates for cytochrome P-450-dependent monooxygenases were screened with rat nasal and, for comparison, liver microsomes. Tested substrates included 6 nasal decongestants, cocaine, nicotine, 9 essences, 3 potential air pollutants, and 12 solvents. Each test substrate, with the possible exception of the air pollutants, contained one or more N-methyl, O-methyl, or S-methyl groups. Eighteen of the tested materials were metabolized to produce formaldehyde by nasal microsomes. Five substrates, namely, the solvents HMPA and dimethylaniline, cocaine, and the essences dimethyl anthranilate and p-methoxyacetophenone, were metabolized to produce formaldehyde at rates exceeding 1000 pmol/mg microsomal protein/min by nasal microsomes. Eight substrates, including four nasal decongestants, nicotine, and an extract of diesel exhaust particles, were metabolized to produce formaldehyde at rates of 200 to 1000 pmol/mg microsomal protein/min. Five other substrates were metabolized to formaldehyde at detectable rates. The results indicate that a variety of materials which often come in contact with the nasal mucosa can be metabolized to formaldehyde by nasal enzymes. The released formaldehyde may influence the irritancy of inhaled compounds and has been suggested to play a role in the tumorigenicity of some compounds.

  3. Alterations in Energy/Redox Metabolism Induced by Mitochondrial and Environmental Toxins: A Specific Role for Glucose-6-Phosphate-Dehydrogenase and the Pentose Phosphate Pathway in Paraquat Toxicity

    PubMed Central

    2015-01-01

    Parkinson’s disease (PD) is a multifactorial disorder with a complex etiology including genetic risk factors, environmental exposures, and aging. While energy failure and oxidative stress have largely been associated with the loss of dopaminergic cells in PD and the toxicity induced by mitochondrial/environmental toxins, very little is known regarding the alterations in energy metabolism associated with mitochondrial dysfunction and their causative role in cell death progression. In this study, we investigated the alterations in the energy/redox-metabolome in dopaminergic cells exposed to environmental/mitochondrial toxins (paraquat, rotenone, 1-methyl-4-phenylpyridinium [MPP+], and 6-hydroxydopamine [6-OHDA]) in order to identify common and/or different mechanisms of toxicity. A combined metabolomics approach using nuclear magnetic resonance (NMR) and direct-infusion electrospray ionization mass spectrometry (DI-ESI-MS) was used to identify unique metabolic profile changes in response to these neurotoxins. Paraquat exposure induced the most profound alterations in the pentose phosphate pathway (PPP) metabolome. 13C-glucose flux analysis corroborated that PPP metabolites such as glucose-6-phosphate, fructose-6-phosphate, glucono-1,5-lactone, and erythrose-4-phosphate were increased by paraquat treatment, which was paralleled by inhibition of glycolysis and the TCA cycle. Proteomic analysis also found an increase in the expression of glucose-6-phosphate dehydrogenase (G6PD), which supplies reducing equivalents by regenerating nicotinamide adenine dinucleotide phosphate (NADPH) levels. Overexpression of G6PD selectively increased paraquat toxicity, while its inhibition with 6-aminonicotinamide inhibited paraquat-induced oxidative stress and cell death. These results suggest that paraquat “hijacks” the PPP to increase NADPH reducing equivalents and stimulate paraquat redox cycling, oxidative stress, and cell death. Our study clearly demonstrates that alterations

  4. A biosensor for monitoring formaldehyde using a new lipophilic tetrathiafulvalene-tetracyanoquinodimethane salt and a polyurethane membrane.

    PubMed

    Kataky, R; Bryce, M R; Goldenberg, L; Hayes, S; Nowak, A

    2002-03-01

    A format for a disposable screen-printed biosensor was investigated for monitoring formaldehyde. The screen-printed sensor format comprised a working electrode (WE) modified with platinised carbon, a new lipophilic tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) salt as mediator, a plasticised polyurethane membrane (TECOFLEX SG80, PU) with anionic sites and the enzyme (formaldehyde dehydrogenase FOH) and co-factor (beta-NAD(+)). The new lipophilic TTF-TCNQ salt gave a smooth, robust electrode surface rather than microcrystalline deposits of the salt observed with TTF-TCNQ salts. Entrapment of the enzyme and co-factor behind a plastcised PU membrane with anionic sites enhanced the sensitivity and stability of the sensor. A linear response between 10(-3) and 10(-4) mol dm(-3) was observed. To demonstrate the feasibility of the use of the screen-printed sensor to monitoring formaldehyde in ambient air, preliminary experiments were carried out in the vicinity of a local medium density fibreboard factory and its performance compared to that of a biosensor made from the same platinised carbon and enzyme system, but without the lipophilic TTF-TCNQ and membrane, using a commercial 'Rank' cell. Samples were collected using a Molspin 'Super-sniffer'. PMID:18968517

  5. 40 CFR 721.9480 - Resorcinol, formaldehyde substituted carbomonocycle resin (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Resorcinol, formaldehyde substituted... New Uses for Specific Chemical Substances § 721.9480 Resorcinol, formaldehyde substituted... chemical substance identified generically as resorcinol, formaldehyde substituted carbomonocycle resin...

  6. 40 CFR 721.9480 - Resorcinol, formaldehyde substituted carbomonocycle resin (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Resorcinol, formaldehyde substituted... New Uses for Specific Chemical Substances § 721.9480 Resorcinol, formaldehyde substituted... chemical substance identified generically as resorcinol, formaldehyde substituted carbomonocycle resin...

  7. 40 CFR 721.9480 - Resorcinol, formaldehyde substituted carbomonocycle resin (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Resorcinol, formaldehyde substituted... New Uses for Specific Chemical Substances § 721.9480 Resorcinol, formaldehyde substituted... chemical substance identified generically as resorcinol, formaldehyde substituted carbomonocycle resin...

  8. 40 CFR 721.9480 - Resorcinol, formaldehyde substituted carbomonocycle resin (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Resorcinol, formaldehyde substituted... New Uses for Specific Chemical Substances § 721.9480 Resorcinol, formaldehyde substituted... chemical substance identified generically as resorcinol, formaldehyde substituted carbomonocycle resin...

  9. Formaldehyde and LeukemiA: Epidemiology, Potential Mechanisms and Implications for Risk Assessment

    EPA Science Inventory

    Formaldehyde is widely used in the United States and other countries. Occupational and environmental exposures to formaldehyde may be associated with an increased risk of leukemia in exposed individuals. However, risk assessment of formaldehyde and leukemia has been challenging ...

  10. Exposure to formaldehyde and its potential human health hazards.

    PubMed

    Kim, Ki-Hyun; Jahan, Shamin Ara; Lee, Jong-Tae

    2011-10-01

    A widely used chemical, formaldehyde is normally present in both indoor and outdoor air. The rapid growth of formaldehyde-related industries in the past two decades reflects the result of its increased use in building materials and other commercial sectors. Consequently, formaldehyde is encountered almost every day from large segments of society due to its various sources. Many governments and agencies around the world have thus issued a series of standards to regulate its exposure in homes, office buildings, workshops, public places, and food. In light of the deleterious properties of formaldehyde, this article provides an overview of its market, regulation standards, and human health effects. PMID:22107164

  11. Formaldehyde crosslinking: a tool for the study of chromatin complexes.

    PubMed

    Hoffman, Elizabeth A; Frey, Brian L; Smith, Lloyd M; Auble, David T

    2015-10-30

    Formaldehyde has been used for decades to probe macromolecular structure and function and to trap complexes, cells, and tissues for further analysis. Formaldehyde crosslinking is routinely employed for detection and quantification of protein-DNA interactions, interactions between chromatin proteins, and interactions between distal segments of the chromatin fiber. Despite widespread use and a rich biochemical literature, important aspects of formaldehyde behavior in cells have not been well described. Here, we highlight features of formaldehyde chemistry relevant to its use in analyses of chromatin complexes, focusing on how its properties may influence studies of chromatin structure and function. PMID:26354429

  12. Effect of natural compounds on reducing formaldehyde emission from plywood

    NASA Astrophysics Data System (ADS)

    Uchiyama, Shigehisa; Matsushima, Erica; Kitao, Nahoko; Tokunaga, Hiroshi; Ando, Masanori; Otsubo, Yasufumi

    The effects of natural compounds on reducing formaldehyde emission from plywood were investigated. Urea, catechin and vanillin were examined as the natural formaldehyde reducers. The microemission cell, with an internal volume of 35 ml, the maximum exposed test surface area of 177 cm 2 and an air purge flow rate of 50 ml min -1, was used to measure specific emission rate (SER). In the case of no reducer treatment, formaldehyde emission from plywood was fast and SERs were 4.4 mg m -2 h -1 at 30 °C and 15 mg m -2 h -1 at 60 °C. When this plywood was treated with the natural compounds, the SERs of formaldehyde were decreased at all temperatures. In the case of urea treatment, the SERs of formaldehyde decreased to 0.30 mg m -2 h -1 at 30 °C and 0.65 mg m -2 h -1 at 60 °C. When the urea treatment was applied to the inside of kitchen cabinet (made from plywood; 270 cm wide, 60 cm deep, 250 cm high), the concentration of formaldehyde was reduced substantially from 1600 to 130 μg m -3. The reducing effect of formaldehyde continued during the observation period (6 months), with a mean concentration of 100 μg m -3. Reducers in the plywood would react with released formaldehyde. Application of natural compounds such as urea, catechin and vanillin could provide a simple and effective approach for suppressing formaldehyde emission from plywood.

  13. Genetics Home Reference: lactate dehydrogenase deficiency

    MedlinePlus

    ... dehydrogenase-B pieces (subunits) of the lactate dehydrogenase enzyme. This enzyme is found throughout the body and is important ... cells. There are five different forms of this enzyme, each made up of four protein subunits. Various ...

  14. Dehydrogenase activity of forest soils depends on the assay used

    NASA Astrophysics Data System (ADS)

    Januszek, Kazimierz; Długa, Joanna; Socha, Jarosław

    2015-01-01

    Dehydrogenases are exclusively intracellular enzymes, which play an important role in the initial stages of oxidation of soil organic matter. One of the most frequently used methods to estimate dehydrogenase activity in soil is based on the use of triphenyltetrazolium chloride as an artificial electron acceptor. The purpose of this study was to compare the activity of dehydrogenases of forest soils with varied physicochemical properties using different triphenyltetrazolium chloride assays. The determination was carried out using the original procedure by Casida et al., a modification of the procedure which involves the use of Ca(OH)2 instead of CaCO3, the Thalmann method, and the assay by Casida et al. without addition of buffer or any salt. Soil dehydrogenase activity depended on the assay used. Dehydrogenase determined by the Casida et al. method without addition of buffer or any salt correlated with the pH values of soils. The autoclaved strongly acidic samples of control soils showed high concentrations of triphenylformazan, probably due to chemical reduction of triphenyltetrazolium chloride. There is, therefore, a need for a sterilization method other than autoclaving, ie a process that results in significant changes in soil properties, thus helping to increase the chemical reduction of triphenyltetrazolium chloride.

  15. Aminotransferase and glutamate dehydrogenase activities in lactobacilli and streptococci.

    PubMed

    Peralta, Guillermo Hugo; Bergamini, Carina Viviana; Hynes, Erica Rut

    2016-01-01

    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. PMID:27266631

  16. Respiratory response to formaldehyde and off-gas of urea formaldehyde foam insulation.

    PubMed Central

    Day, J H; Lees, R E; Clark, R H; Pattee, P L

    1984-01-01

    In 18 subjects, 9 of whom had previously complained of various nonrespiratory adverse effects from the urea formaldehyde foam insulation (UFFI) in their homes, pulmonary function was assessed before and after exposure in a laboratory. On separate occasions formaldehyde, 1 part per million (ppm), and UFFI off-gas yielding a formaldehyde concentration of 1.2 ppm, were delivered to each subject in an environmental chamber for 90 minutes and a fume hood for 30 minutes respectively. None of the measures of pulmonary function used (forced vital capacity, forced expiratory volume in 1 second or maximal midexpiratory flow rate) showed any clinically or statistically significant response to the exposure either immediately after or 8 hours after its beginning. There were no statistically significant differences between the responses of the group that had previously complained of adverse effects and of the group that had not. There was no evidence that either formaldehyde or UFFI off-gas operates as a lower airway allergen or important bronchospastic irritant in this heterogeneous population. Images Fig. 1 PMID:6388780

  17. Effect of molecular structure of aniline-formaldehyde copolymers on corrosion inhibition of mild steel in hydrochloric acid solution.

    PubMed

    Zhang, Yan; Nie, Mengyan; Wang, Xiutong; Zhu, Yukun; Shi, Fuhua; Yu, Jianqiang; Hou, Baorong

    2015-05-30

    Aniline-formaldehyde copolymers with different molecular structures have been prepared and investigated for the purpose of corrosion control of mild steel in hydrochloric acid. The copolymers were synthesized by a condensation polymerization process with different ratios of aniline to formaldehyde in acidic precursor solutions. The corrosion inhibition efficiency of as-synthesized copolymers for Q235 mild steel was investigated in 1.0 mol L(-1) hydrochloric acid solution by weight loss measurement, potentiodynamic polarization, and electrochemical impedance spectroscopy, respectively. All the results demonstrate that as-prepared aniline-formaldehyde copolymers are efficient mixed-type corrosion inhibitors for mild steels in hydrochloric acid. The corrosion inhibition mechanism is discussed in terms of the role of molecular structure on adsorption of the copolymers onto the steel surface in acid solution. PMID:25723887

  18. Low temperature steam and formaldehyde sterilization.

    PubMed

    Robertshaw, R G

    1983-09-01

    A standard low temperature steam/formaldehyde autoclave was tested according to the manufacturer's instructions, using a range of test pieces containing Bacillus stearothermophilus spores as the challenge organism. There were failures in killing the challenge organism and the reasons for these are discussed. A description of modifications made to the autoclave is given together with details of an improved operating cycle. The performance of the modified autoclave was greatly improved and conditions were established for reliable and consistent sterilization of all the test pieces. A commercially produced prototype autoclave similarly modified also showed effective sterilization. PMID:6195245

  19. Low density, resorcinol-formaldehyde aerogels

    DOEpatents

    Pekala, R.W.

    1989-10-10

    The polycondensation of resorcinol with formaldehyde under alkaline conditions results in the formation of surface functionalized polymer clusters. The covalent crosslinking of these clusters produces gels which when processed under supercritical conditions, produce low density, organic aerogels (density [<=]100 mg/cc; cell size [<=]0.1 microns). The aerogels are transparent, dark red in color and consist of interconnected colloidal-like particles with diameters of about 100 [angstrom]. These aerogels may be further carbonized to form low density carbon foams with cell size of about 0.1 micron.

  20. Low density, resorcinol-formaldehyde aerogels

    DOEpatents

    Pekala, Richard W.

    1991-01-01

    The polycondensation of resorcinol with formaldehyde under alkaline conditions results in the formation of surface functionalized polymer "Clusters". The covalent crosslinking of these "clusters" produces gels which when processed under supercritical conditions, produce low density, organic aerogels (density.ltoreq.100 mg/cc; cell size .ltoreq.0.1 microns). The aerogels are transparent, dark red in color and consist of interconnected colloidal-like particles with diameters of about 100.circle.. These aerogels may be further carbonized to form low density carbon foams with cell size of about 0.1 micron.

  1. Low density, resorcinol-formaldehyde aerogels

    DOEpatents

    Pekala, R.W.

    1988-05-26

    The polycondensation of resorcinol with formaldehyde under alkaline conditions results in the formation of surface functionalized polymer ''clusters''. The covalent crosslinking of these ''clusters'' produces gels which when processed under supercritical conditions, produce low density, organic aerogels (density less than or equal to100 mg/cc; cell size less than or equal to0.1 microns). The aerogels are transparent,dark red in color and consist of interconnected colloidal-like particles with diameters of about 100 A/degree/. These aerogels may be further carbonized to form low density carbon foams with cell size of about 0.1 micron. 1 fig., 1 tab.

  2. Low density, resorcinol-formaldehyde aerogels

    DOEpatents

    Pekala, Richard W.

    1989-01-01

    The polycondensation of resorcinol with formaldehyde under alkaline conditions results in the formation of surface functionalized polymer "clusters". The covalent crosslinking of these "clusters" produces gels which when processed under supercritical conditions, produce low density, organic aerogels (density .ltoreq.100 mg/cc; cell size .ltoreq.0.1 microns). The aerogels are transparent, dark red in color and consist of interconnected colloidal-like particles with diameters of about 100 .ANG.. These aerogels may be further carbonized to form low density carbon foams with cell size of about 0.1 micron.

  3. Effect of Formaldehyde on Asthmatic Response to Inhaled Allergen Challenge

    PubMed Central

    Ezratty, Véronique; Bonay, Marcel; Neukirch, Catherine; Orset-Guillossou, Gaëlle; Dehoux, Monique; Koscielny, Serge; Cabanes, Pierre-André; Lambrozo, Jacques; Aubier, Michel

    2007-01-01

    Background Exposure to formaldehyde may lead to exacerbation of asthma. Objectives Our aim in this study was to investigate whether exposure to a low level (500 μg/m3) of formaldehyde enhances inhaled allergen responses. Methods Twelve subjects with intermittent asthma and allergy to pollen were exposed, at rest, in a double-blind crossover study to either formaldehyde or purified air for 60 min. The order of exposure to formaldehyde and air-only was randomized, and exposures were separated by 2 weeks. We also performed an allergen inhalation challenge after each exposure. Airway responsiveness to methacholine and lower airway inflammation (induced sputum) were assessed 8 hr after allergen challenge. Results The median dose of allergen producing a 15% decrease in forced expiratory volume in 1 sec (PD15FEV1) was 0.80 IR (index of reactivity) after formaldehyde exposure compared with 0.25 IR after air-only exposure (p = 0.06). Formaldehyde exposure did not affect allergen-induced increase in responsiveness to methacholine (p = 0.42). We found no formaldehyde-associated effect on the airway inflammatory response, in particular the eosinophilic inflammatory response, induced by the allergen challenge 8 hr before. Conclusion In this study, exposure to 500 μg/m3 formaldehyde had no significant deleterious effect on airway allergen responsiveness of patients with intermittent asthma; we found a trend toward a protective effect. PMID:17384766

  4. Chromogenic Detection of Aqueous Formaldehyde Using Functionalized Silica Nanoparticles.

    PubMed

    El Sayed, Sameh; Pascual, Lluı́s; Licchelli, Maurizio; Martínez-Máñez, Ramón; Gil, Salvador; Costero, Ana M; Sancenón, Félix

    2016-06-15

    Silica nanoparticles functionalized with thiol reactive units and bulky polar polyamines were used for the selective colorimetric detection of formaldehyde. The reaction of thiols groups in the nanoparticles surface with a squaraine dye resulted in loss of the π-conjugation of the chromophores, and the subsequent bleaching of the solution. However, when formaldehyde was present in the suspension, the thiol-squaraine reaction was inhibited and a chromogenic response was observed. A selective response to formaldehyde was observed only when the thiol and polyamine groups were anchored to the silica surface. The observed selective response was ascribed to the fact that bulky polyamines generate a highly polar environment around thiols, which were only able to react with the small and polar formaldehyde, but not with other aldehydes. The sensing nanoparticles showed a limit of detection (LOD) for formaldehyde of 36 ppb in water. PMID:27250594

  5. Determination of tritiated formaldehyde in effluents from tritium facilities

    SciTech Connect

    Belot, Y.; Camus, H.; Marini, T. )

    1992-03-01

    Recent observations suggested that formal-dehyde can be incorporated in vegetation at a very high rate. In this paper, the authors develop a methodology for determining tritiated formaldehyde (CHTO) in gaseous effluent containing HTO and HT as dominant species. CHTO being very soluble in water is collected in a solution of carrier formaldehyde. This carrier is necessary for precipitating for formaldehyde derivative of dimedone and collecting it by filtration. The precipitate, which contains the formaldehyde hydrogens, is freed from exchangeable tritium, dried in oven, and combusted to water for tritium determination. CHTO can thus be separated from HTO with a high efficiency, leading to the possibility of determining accurately 1 Bq of CHTO in as much as 5 {times} 10{sup 4} Bq of HTO. The methodology has been applied in preliminary experiments to determine the ratio of CHTO to HTO in effluent from a tritium-handling facility and effluent released from solid miscellaneous wastes.

  6. Formaldehyde: an analysis of its respiratory, cutaneous, and immunologic effects

    SciTech Connect

    Bardana, E.J. Jr.; Montanaro, A. )

    1991-06-01

    Formaldehyde is truly ubiquitous in our ecology and continuing important commercial applications. Most of us have daily contact with this chemical. The most significant outdoor source of this chemical is gasoline and diesel fuel combustion. The primary indoor source is combustion of tobacco products. Formaldehyde is associated with a disagreeable odor that can produce annoyance symptoms and at higher concentrations can be a transient and completely reversible irritant to the eyes and mucous membranes of the respiratory tract. It is so soluble and rapidly metabolized that it rarely reaches the lower respiratory tract to inflict damage. The exception is in cigarette smokers who actively inhale. Formaldehyde may on rare occasions induce bronchial asthma at relatively high exposure doses. There are no conclusive studies that prove the development of de novo IgE-mediated respiratory tract symptoms secondary to inhalation of formaldehyde vapors. The approach to formaldehyde-induced symptoms should be one of careful documentation of objective physiologic changes.147 references.

  7. Imaging Surface Reactions of Formaldehyde on TiO2

    NASA Astrophysics Data System (ADS)

    Zhang, Zhenrong; Tang, Miru; Wang, Zhi-Tao; Ke, Zhu; Xia, Yaobiao; Park, Kenneth; Lyubinetsky, Igor; Dohnálek, Zdenek; Ge, Qingfeng

    2015-03-01

    Formaldehyde is involved in many surface catalytic and photo-catalytic reactions on metal oxides. We studied surface reactions of formaldehyde on reduced TiO2(110) surfaces using variable-temperature scanning tunneling microscopy (STM) and density functional theory (DFT). STM images taken from a same area at various temperatures clearly show that formaldehyde preferentially adsorbs on the bridge-bonded oxygen vacancy (VO) defect sites. Bias-dependent STM images suggest the bonding configurations of the Ti-bound CH2O and the VO-bound CH2O. The isothermal time dependent images show the rotation of VO-bound CH2O and the two diffusion channels of formaldehyde at different temperatures. We also directly observed the formation of formaldehyde dimmer.

  8. Formaldehyde: an analysis of its respiratory, cutaneous, and immunologic effects.

    PubMed

    Bardana, E J; Montanaro, A

    1991-06-01

    Formaldehyde is truly ubiquitous in our ecology and continuing important commercial applications. Most of us have daily contact with this chemical. The most significant outdoor source of this chemical is gasoline and diesel fuel combustion. The primary indoor source is combustion of tobacco products. Formaldehyde is associated with a disagreeable odor that can produce "annoyance" symptoms and at higher concentrations can be a transient and completely reversible irritant to the eyes and mucous membranes of the respiratory tract. It is so soluble and rapidly metabolized that it rarely reaches the lower respiratory tract to inflict damage. The exception is in cigarette smokers who actively inhale. Formaldehyde may on rare occasions induce bronchial asthma at relatively high exposure doses. There are no conclusive studies that prove the development of de novo IgE-mediated respiratory tract symptoms secondary to inhalation of formaldehyde vapors. The approach to formaldehyde-induced symptoms should be one of careful documentation of objective physiologic changes. PMID:2048760

  9. Increased IMP dehydrogenase gene expression in solid tumor tissues and tumor cell lines

    SciTech Connect

    Collart, F.R.; Chubb, C.B.; Mirkin, B.L.; Huberman, E.

    1992-07-10

    IMP dehydrogenase, a regulatory enzyme of guanine nucleotide biosynthesis, may play a role in cell proliferation and malignancy. To assess this possibility, we examined IMP dehydrogenase expression in a series of human solid tumor tissues and tumor cell lines in comparison with their normal counterparts. Increased IMP dehydrogenase gene expression was observed in brain tumors relative to normal brain tissue and in sarcoma cells relative to normal fibroblasts. Similarly, in several B- and T-lymphoid leukemia cell lines, elevated levels of IMP dehydrogenase mRNA and cellular enzyme were observed in comparison with the levels in peripheral blood lymphocytes. These results are consistent with an association between increased IMP dehydrogenase expression and either enhanced cell proliferation or malignant transformation.

  10. Partially-irreversible sorption of formaldehyde in five polymers

    NASA Astrophysics Data System (ADS)

    Ye, Wei; Cox, Steven S.; Zhao, Xiaomin; Frazier, Charles E.; Little, John C.

    2014-12-01

    Due to its environmental ubiquity and concern over its potential toxicity, the mass-transfer characteristics of formaldehyde are of critical importance to indoor air quality research. Previous studies have suggested that formaldehyde mass transfer in polymer is partially irreversible. In this study, mechanisms that could cause the observed irreversibility were investigated. Polycarbonate and four other polymeric matrices were selected and subjected to formaldehyde sorption/desorption cycles. Mass transfer of formaldehyde was partially irreversible in all cases, and three potential mechanisms were evaluated. First, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) analysis was used to investigate possible formaldehyde polymerization on polymer surfaces. ATR-FTIR showed no detectable paraformaldehyde or formaldehyde on the film surfaces that had been exposed to formaldehyde and air. ATR-FTIR did detect aliphatic acids suggesting oxidation had occurred on film surfaces as a result of exposure to formaldehyde. However, additional study suggested that air is not the primary cause for irreversibility. Second, statistical physics theory was tested as a possible explanation. According to this theory, reversible and irreversible sorption could be taking place simultaneously. The irreversible fraction should be constant during sorption and the fraction could be determined by performing a complete sorption/desorption test. The sorption/desorption data was consistent with this theory. Third, chemisorption was considered as another possible cause for irreversibility. Extraction/fluorimetry testing of post-sorption and post-desorption polymer films showed measurable quantities of formaldehyde suggesting that some of the chemisorbed formaldehyde was reversible at the higher extraction temperature. Further quantitative study on chemical reaction products is needed.

  11. Formaldehyde exposure and acute health effects study

    SciTech Connect

    Quackenboss, J.J.; Lebowitz, M.D.; Michaud, J.P.; Bronnimann, D. )

    1989-01-01

    To assess the effects of formaldehyde exposures on health, exposure groups were defined using baseline exposure and health questionnaires. Formaldehyde concentrations were poorly correlated with these exposure classifications, perhaps due to the time delay between classification and monitoring. The 151 households reported here had a mean HCHO concentration of 35 (S.E. 1.5 and median 30) {mu}g/m{sup 3}. Passive samplers prepared in our lab were calibrated in a chamber to derive an estimated sampling rate of 0.311 {mu}g/(mg {center dot} m{sup {minus}3} {center dot} hr). They were also compared to commercially available samplers inside of the homes, with a correlation coefficient of 0.896 and mean difference of 2.6 {mu}g/m{sup 3}. In this report of initial findings from an ongoing study, daily symptoms and peak expiratory flow measurements were compared with an HCHO exposure classification based on the median measured concentrations. None of the symptoms groups were related to HCHO exposure when controlling for age and sex. There was a significant relationship between HCHO exposure and variability in peak expiratory flows that was dependent on age group. It may be especially important to assess the variability in reactive individuals and children to determine the short-term effects of HCHO exposures and possible long-term consequences.

  12. Aβ seeds resist inactivation by formaldehyde

    PubMed Central

    Fritschi, Sarah K.; Cintron, Amarallys; Ye, Lan; Mahler, Jasmin; Bühler, Anika; Baumann, Frank; Neumann, Manuela; Nilsson, K. Peter R.; Hammarström, Per; Walker, Lary C.; Jucker, Mathias

    2014-01-01

    Cerebral β-amyloidosis can be exogenously induced by the intracerebral injection of brain extracts containing aggregated β-amyloid (Aβ) into young, pre-depositing Aβ precursor protein- (APP) transgenic mice. Previous work has shown that the induction involves a prion-like seeding mechanism in which the seeding agent is aggregated Aβ itself. Here we report that the β-amyloid-inducing activity of Alzheimer’s disease (AD) brain tissue or aged APP-transgenic mouse brain tissue is preserved, albeit with reduced efficacy, after formaldehyde fixation. Moreover, spectral analysis with amyloid conformation-sensitive luminescent conjugated oligothiophene dyes reveals that the strain-like properties of aggregated Aβ are maintained in fixed tissues. The resistance of Aβ seeds to inactivation and structural modification by formaldehyde underscores their remarkable durability, which in turn may contribute to their persistence and spread within the body. The present findings can be exploited to establish the relationship between the molecular structure of Aβ aggregates and the variable clinical features and disease progression of AD even in archived, formalin-fixed autopsy material. PMID:25193240

  13. Aβ seeds resist inactivation by formaldehyde.

    PubMed

    Fritschi, Sarah K; Cintron, Amarallys; Ye, Lan; Mahler, Jasmin; Bühler, Anika; Baumann, Frank; Neumann, Manuela; Nilsson, K Peter R; Hammarström, Per; Walker, Lary C; Jucker, Mathias

    2014-10-01

    Cerebral β-amyloidosis can be exogenously induced by the intracerebral injection of brain extracts containing aggregated β-amyloid (Aβ) into young, pre-depositing Aβ precursor protein- (APP) transgenic mice. Previous work has shown that the induction involves a prion-like seeding mechanism in which the seeding agent is aggregated Aβ itself. Here we report that the β-amyloid-inducing activity of Alzheimer's disease (AD) brain tissue or aged APP-transgenic mouse brain tissue is preserved, albeit with reduced efficacy, after formaldehyde fixation. Moreover, spectral analysis with amyloid conformation-sensitive luminescent conjugated oligothiophene dyes reveals that the strain-like properties of aggregated Aβ are maintained in fixed tissues. The resistance of Aβ seeds to inactivation and structural modification by formaldehyde underscores their remarkable durability, which in turn may contribute to their persistence and spread within the body. The present findings can be exploited to establish the relationship between the molecular structure of Aβ aggregates and the variable clinical features and disease progression of AD even in archived, formalin-fixed autopsy material. PMID:25193240

  14. ACTION OF FORMALDEHYDE ON ENZYMES AND ON CERTAIN PBOTEIDS

    PubMed Central

    Bliss, C. L.; Novy, F. G.

    1899-01-01

    The following general conclusions may be drawn from the preceding work: Fibrin is altered by formaldehyde and is then less easily digested by pepsin and by trypsin. Papaïn is apparently unable to digest fibrin even when this is exposed to very weak formaldehyde (1:1000) for a very short time. The casein of milk, on contact with formaldehyde, undergoes rapid alteration and is as a result not coagulated by rennet, or but very slowly. Such altered casein, like similar fibrin, is not readily digested by the proteolytic ferments. The longer the formaldehyde acts on casein and on fibrin the more marked is the result. Pepsin is not affected by a one per cent solution of formaldehyde, even when the mixture has stood for four weeks. Even a five per cent solution of formaldehyde acting for three weeks has no effect on pepsin. Contrary results obtained by others are due to an alteration of the fibrin by the formaldehyde. A putrid solution of pepsin in distilled water one month old digests fibrin as readily as a fresh solution. Rennet is not affected even by a four per cent solution of formaldehyde acting for several weeks. The absence of coagulation at times is due to the action of formaldehyde on the casein of the milk and not on the rennet ferment. Papaïn is very quickly altered by formaldehyde, even in very dilute solution. Moreover, it is unable to digest fibrin that has been exposed to the action of a very dilute solution of formaldehyde for a short time. Trypsin is altered by formaldehyde to such an extent that digestion of fibrin will not take place, or but very slowly. The extent to which trypsin is affected by formaldehyde depends largely upon the amount of organic matter present, as well as on the amount of ferment in the solution. Amylopsin is not destroyed by very dilute solutions of formaldehyde, but stronger solutions decrease the activity of the ferment, and if used in sufficient concentration will destroy it completely. Ptyalin, like the diastatic ferment of

  15. 21 CFR 177.1460 - Melamine-formaldehyde resins in molded articles.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Melamine-formaldehyde resins in molded articles...-formaldehyde resins in molded articles. Melamine-formaldehyde resins may be safely used as the food-contact...: (a) For the purpose of this section, melamine-formaldehyde resins are those produced when 1 mole...

  16. 21 CFR 177.1460 - Melamine-formaldehyde resins in molded articles.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Melamine-formaldehyde resins in molded articles...-formaldehyde resins in molded articles. Melamine-formaldehyde resins may be safely used as the food-contact...: (a) For the purpose of this section, melamine-formaldehyde resins are those produced when 1 mole...

  17. 21 CFR 177.1460 - Melamine-formaldehyde resins in molded articles.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Melamine-formaldehyde resins in molded articles...-formaldehyde resins in molded articles. Melamine-formaldehyde resins may be safely used as the food-contact...: (a) For the purpose of this section, melamine-formaldehyde resins are those produced when 1 mole...

  18. Proportional mortality patterns among chemical plant workers exposed to formaldehyde.

    PubMed Central

    Marsh, G M

    1982-01-01

    To examine the possible health risks associated with occupational exposure to formaldehyde a proportional mortality analysis was conducted on deaths occurring between 1950 and 1976 among 136 men who had been employed a month or more in one of five formaldehyde-related areas of a large chemical producing plant located in Springfield, Massachusetts, USA. Overall, no statistically significant excesses or deficits in proportional mortality were observed among the formaldehyde-exposed group based on comparisons with both United States men and men from the local county area. In addition, no important differences in mortality were observed among this group when comparisons were made with 456 male decedents from the same plant who had not had a month or more of formaldehyde exposure. Within the calendar period examined, no deaths from sinonasal cancer were observed among the chemical workers studied nor was mention made on any death certificate of sinonasal cancer as a contributory cause of death. No important excesses, trends, or patterns in cancer mortality were observed among white male formadelhyde-exposed workers when consideration was given to age and time period of death, type and duration of formaldehyde exposure, and the lapse period from the onset of the first formaldehyde-related job assignment. Although certain limitations of this study do not allow definite conclusions to be drawn, the results indicate no trends or patterns in proportional mortality that could be directly linked to exposures to formaldehyde. PMID:7138792

  19. INSTRUCTIONS FOR OPERATING LBL FORMALDEHYDE SAMPLER

    SciTech Connect

    Fanning, L.Z.; Allen, J.R.; Miksch, R.R.

    1981-09-01

    The LBL formaldehyde sampler consists of two parts: 1) a pump box and 2) a small refrigerator housing sampling bubblers. The pump box contains two pumps, a timer, a flow controller, an electrical cord, and a ten-foot piece of tubing to connect the refrigerator to the pump box. The small refrigerator contains four columns of bubbler sampling trains attached to a metal plate. Two sampling trains each are plumbed in parallel to two sampling ports on the back of the refrigerator. The two sampling lines supplied are to be attached to these ports to allow two locations to be sampled at once (usually one indoor and one outdoor). The refrigerator also contains a rack for holding bubbler tubes. In the sampling process, air is drawn through a sampling line attached to the fitting at the back of the refrigerator and into a prlmary bubbler containing a trapping solution. This trapping solution can be distilled water or an aqueous solution of some compound that reacts with formaldehyde. From this bubbler the air goes through a second bubbler containing the same trapping solution as the first bubbler. (To maintain sample integrity, all parts that the air sample contacts are made of Teflon, polypropylene, and stainless steel.) The air then goes into the third bubbler, which contains no liquid. This bubbler contains a hypodermic needle that serves as a flow-control orifice. The hypodermic needle, in conjunction with the flow controller in the pump box, ensures a constant a flow rate. The refrigerator contains four columns of these sets of three bubblers. After samples have been collected, the bubbler bottoms are detached and the contents of the first and second bubblers in each column are poured together, capped, and labeled. The use of a refrigerated primary and secondary bubbler whose contents are combined at the end of a sampling period ensures 95% collection efficiency. After the bubbler tubes are capped and labeled, they are stored either in the rack supplied in the

  20. Efficiency of superoxide anions in the inactivation of selected dehydrogenases

    NASA Astrophysics Data System (ADS)

    Rodacka, Aleksandra; Serafin, Eligiusz; Puchala, Mieczyslaw

    2010-09-01

    The most ubiquitous of the primary reactive oxygen species, formed in all aerobes, is the superoxide free radical. It is believed that the superoxide anion radical shows low reactivity and in oxidative stress it is regarded mainly as an initiator of more reactive species such as rad OH and ONOO -. In this paper, the effectiveness of inactivation of selected enzymes by radiation-generated superoxide radicals in comparison with the effectiveness of the other products of water radiolysis is examined. We investigate three enzymes: glyceraldehyde-3-phosphate dehydrogenase (GAPDH), alcohol dehydrogenase (ADH) and lactate dehydrogenase (LDH). We show that the direct contribution of the superoxide anion radical to GAPDH and ADH inactivation is significant. The effectiveness of the superoxide anion in the inactivation of GAPDH and ADG was only 2.4 and 2.8 times smaller, respectively, in comparison with hydroxyl radical. LDH was practically not inactivated by the superoxide anion. Despite the fact that the studied dehydrogenases belong to the same class of enzymes (oxidoreductases), all have a similar molecular weight and are tetramers, their susceptibility to free-radical damage varies. The differences in the radiosensitivity of the enzymes are not determined by the basic structural parameters analyzed. A significant role in inactivation susceptibility is played by the type of amino acid residues and their localization within enzyme molecules.

  1. Photochemical production of formaldehyde in earth's primitive atmosphere

    NASA Astrophysics Data System (ADS)

    Pinto, J. P.; Gladstone, G. R.; Yung, Y. L.

    1980-10-01

    Formaldehyde could have been produced by photochemical reactions in the earth's primitive atmosphere, at a time when it consisted mainly of molecular nitrogen, water vapor, carbon dioxide, and trace amounts of molecular hydrogen and carbon monoxide. Removal of formaldehyde from the atmosphere by precipitation can provide a source of organic carbon to the oceans at the rate of 100 billion moles per year. Subsequent reactions of formaldehyde in primeval aquatic environments would have implications for the abiotic synthesis of complex organic molecules and the origin of life.

  2. Photochemical production of formaldehyde in earth's primitive atmosphere

    NASA Technical Reports Server (NTRS)

    Pinto, J. P.; Gladstone, G. R.; Yung, Y. L.

    1980-01-01

    Formaldehyde could have been produced by photochemical reactions in the earth's primitive atmosphere, at a time when it consisted mainly of molecular nitrogen, water vapor, carbon dioxide, and trace amounts of molecular hydrogen and carbon monoxide. Removal of formaldehyde from the atmosphere by precipitation can provide a source of organic carbon to the oceans at the rate of 100 billion moles per year. Subsequent reactions of formaldehyde in primeval aquatic environments would have implications for the abiotic synthesis of complex organic molecules and the origin of life.

  3. Formaldehyde: a candidate toxic air contaminant. Final report

    SciTech Connect

    Frye, B.; Parker, T.

    1988-03-01

    Formaldehyde (HCHO) is a gas widely used in adhesives and resins, textiles, embalming fluids, fungicides, air fresheners, and cosmetics. It is directly emitted into the ambient outdoor air from vehicular and stationary sources, and is also produced in the atmosphere from other substances by photochemical smog processes. The International Agency for Research on Cancer (IARC) has determined that there is sufficient evidence for carcinogenicity of formaldehyde to animals, and limited evidence for carcinogenicity to humans. EPA classifies formaldehyde as a probable human carcinogen with a one in a million risk concentration of 0.08 ppb.

  4. Formaldehyde fixation contributes to detoxification for growth of a nonmethylotroph, Burkholderia cepacia TM1, on vanillic acid.

    PubMed

    Mitsui, Ryoji; Kusano, Yoko; Yurimoto, Hiroya; Sakai, Yasuyoshi; Kato, Nobuo; Tanaka, Mitsuo

    2003-10-01

    During bacterial degradation of methoxylated lignin monomers, such as vanillin and vanillic acid, formaldehyde is released through the reaction catalyzed by vanillic acid demethylase. When Burkholderia cepacia TM1 was grown on vanillin or vanillic acid as the sole carbon source, the enzymes 3-hexulose-6-phosphate synthase (HPS) and 6-phospho-3-hexuloisomerase (PHI) were induced. These enzymes were also expressed during growth on Luria-Bertani medium containing formaldehyde. To understand the roles of these enzymes, the hps and phi genes from a methylotrophic bacterium, Methylomonas aminofaciens 77a, were introduced into B. cepacia TM1. The transformant strain constitutively expressed the genes for HPS and PHI, and these activities were two- or threefold higher than the activities in the wild strain. Incorporation of [14C]formaldehyde into the cell constituents was increased by overexpression of the genes. Furthermore, the degradation of vanillic acid and the growth yield were significantly improved at a high concentration of vanillic acid (60 mM) in the transformant strain. These results suggest that HPS and PHI play significant roles in the detoxification and assimilation of formaldehyde. This is the first report that enhancement of the HPS/PHI pathway could improve the degradation of vanillic acid in nonmethylotrophic bacteria. PMID:14532071

  5. Interpreting satellite column observations of formaldehyde over tropical South America.

    PubMed

    Palmer, Paul I; Barkley, Michael P; Kurosu, Thomas P; Lewis, Alastair C; Saxton, Julie E; Chance, Kelly; Gatti, Luciana V

    2007-07-15

    Space-borne column measurements of formaldehyde (HCHO), a high-yield oxidation product of volatile organic compounds (VOCs), represent important constraints for quantifying net regional fluxes of VOCs. Here, we interpret observed distributions of HCHO columns from the Global Ozone Monitoring Experiment (GOME) over tropical South America during 1997-2001. We present the first comparison of year-long in situ isoprene concentrations and fire-free GOME HCHO columns over a tropical ecosystem. GOME HCHO columns and in situ isoprene concentrations are elevated in the wet and dry seasons, with the highest values in the dry season. Previous analysis of the in situ data highlighted the possible role of drought in determining the elevated concentrations during the dry season, inferring the potential of HCHO columns to provide regional-scale constraints for estimating the role of drought on isoprene emissions. The agreement between the observed annual cycles of GOME HCHO columns and Along-Track Scanning Radiometer firecount data over the Amazon basin (correlations typically greater than 0.75 for a particular year) illustrates the potential of HCHO column to provide quantitative information about biomass burning emissions. PMID:17513262

  6. A role for glutathione, independent of oxidative stress, in the developmental toxicity of methanol

    SciTech Connect

    Siu, Michelle T.; Shapiro, Aaron M.; Wiley, Michael J.; Wells, Peter G.

    2013-12-15

    Oxidative stress and reactive oxygen species (ROS) have been implicated in the teratogenicity of methanol (MeOH) in rodents, both in vivo and in embryo culture. We explored the ROS hypothesis further in vivo in pregnant C57BL/6J mice. Following maternal treatment with a teratogenic dose of MeOH, 4 g/kg via intraperitoneal (ip) injection on gestational day (GD) 12, there was no increase 6 h later in embryonic ROS formation, measured by 2′,7′-dichlorodihydrofluorescin diacetate (DCFH-DA) fluorescence, despite an increase observed with the positive control ethanol (EtOH), nor was there an increase in embryonic oxidatively damaged DNA, quantified as 8-oxo-2′-deoxyguanosine (8-oxodG) formation. MeOH teratogenicity (primarily ophthalmic anomalies, cleft palate) also was not altered by pre- and post-treatment with varying doses of the free radical spin trapping agent alpha-phenyl-N-tert-butylnitrone (PBN). In contrast, pretreatment with L-buthionine-(S,R)-sulfoximine (BSO), an inhibitor of glutathione (GSH) synthesis, depleted maternal hepatic and embryonic GSH, and enhanced some new anomalies (micrognathia, agnathia, short snout, fused digits, cleft lip, low set ears), but not the most common teratogenic effects of MeOH (ophthalmic anomalies, cleft palate) in this strain. These results suggest that ROS did not contribute to the teratogenic effects of MeOH in this in vivo mouse model, in contrast to results in embryo culture from our laboratory, and that the protective effect of GSH in this model may arise from its role as a cofactor for formaldehyde dehydrogenase in the detoxification of formaldehyde. - Highlights: • In vivo, a free radical scavenger did not block methanol (MeOH) teratogenesis. • MeOH did not increase embryonic reactive oxygen species formation or DNA oxidation. • MeOH teratogenesis was enhanced by glutathione (GSH) depletion. • GSH may protect as the cofactor for formaldehyde dehydrogenase (ADH3). • Formaldehyde may be a ROS

  7. Measurement of formaldehyde in clean air

    SciTech Connect

    Neitzert, V.; Seiler, W.

    1981-01-01

    A method for the measurement of small amounts of formaldehyde in air has been developed. The method is based on the derivatization of HCHO with 2.4-Denetrophenylhydragine, forming 2.4-Dentrophylhydragine, measured with GC-ECD-technique. HCHO is preconcentrated using a cryogenic sampling technique. The detection limit is 0.05 ppbv for a sampling volume of 200 liter. The method has been applied for measurements in continental and marine air masses showing HCHO mixing ratios of 0.4--5.0 ppbv and 0.2--1.0 ppbv, respectively. HCHO mixing ratios show diurnal variations with maximum values during the early afternoon and minimum values during the early morning. In continental air, HCHO mixing ratios are positively correlated with CO and SO/sub 2/, indicating anthropogenic HCHO sources which are estimated to be 6--11 x 10/sup 12/g/year/sup -1/ on a global scale.

  8. High efficiency annual denuder for formaldehyde monitoring

    SciTech Connect

    Cecchini, F.; Febo, A.; Possanzini, M.

    1985-01-01

    A practical and correct methodology for evaluating CH/sub 2/O in air without sampling artifact formation is presented. Formaldehyde is collected on an annual denuder coated with bisulfite-triethanolamine. The sorbent layer is extracted with water and the solution analyzed by the chromotropic acid (CTA) procedure. Sorption efficiency and loading capacity have been investigated along with storage stability. Results of laboratory validation studies have indicated that a small annual denuder was able to sample about 300 ..mu..g CH/sub 2/O without an appreciable decrease in the initial collection efficiency (99% at 2.5 1 min/sup -1/). Tests on storage stability before and after exposure have also demonstrated that both oxidation of bisulfite and release of CH/sub 2/O did not occur for time periods as long as 1 month.

  9. Chronic respiratory effects of indoor formaldehyde exposure

    SciTech Connect

    Krzyzanowski, M.; Quackenboss, J.J.; Lebowitz, M.D.

    1990-01-01

    The relation of chronic respiratory symptoms and pulmonary function to formaldehyde (HCHO) in homes was studied in a sample of 298 children (6-15 years of age) and 613 adults. HCHO measurements were made with passive samplers two one-week periods. Data on chronic cough and phlegm, wheeze, attacks of breathlessness, and doctor diagnoses of chronic bronchitis and asthma were collected with self-completed questionnaires. Peak expiratory flow rates (PEFR) were obtained during the evenings and mornings for up to 14 consecutive days for each individual. Significantly greater prevalence rates of asthma and chronic bronchitis were found in children from houses with HCHO levels 60-120 ppb than in those less exposed, especially in children also exposed to environmental tobacco smoke. In children, levels of PEFR linearly decreased with HCHO exposure, with estimated decrease due to 60 ppb of HCHO equivalent to 22% of PEFR level in nonexposed children.

  10. Application of toxicogenomic profiling to evaluate effects of benzene and formaldehyde: from yeast to human

    PubMed Central

    McHale, Cliona M.; Smith, Martyn T.; Zhang, Luoping

    2014-01-01

    Genetic variation underlies a significant proportion of the individual variation in human susceptibility to toxicants. The primary current approaches to identify gene–environment (GxE) associations, genome-wide association studies (GWAS) and candidate gene association studies, require large exposed and control populations and an understanding of toxicity genes and pathways, respectively. This limits their application in the study of GxE associations for the leukemogens benzene and formaldehyde, whose toxicity has long been a focus of our research. As an alternative approach, we applied innovative in vitro functional genomics testing systems, including unbiased functional screening assays in yeast and a near-haploid human bone marrow cell line (KBM7). Through comparative genomic and computational analyses of the resulting data, we have identified human genes and pathways that may modulate susceptibility to benzene and formaldehyde. We have validated the roles of several genes in mammalian cell models. In populations occupationally exposed to low levels of benzene, we applied peripheral blood mononuclear cell transcriptomics and chromosome-wide aneuploidy studies (CWAS) in lymphocytes. In this review of the literature, we describe our comprehensive toxicogenomic approach and the potential mechanisms of toxicity and susceptibility genes identified for benzene and formaldehyde, as well as related studies conducted by other researchers. PMID:24571325

  11. Tunable, functional carbon spheres derived from rapid synthesis of resorcinol-formaldehyde resins.

    PubMed

    Pol, Vilas G; Shrestha, Lok Kumar; Ariga, Katsuhiko

    2014-07-01

    In this article, the rapid synthesis of colloidal, spherical polymer resins via enhanced copolymerization and polycondensation of resorcinol with formaldehyde is presented. The ultrasound-mediated technique assembles perfectly spherical resins in less than 5 min due to generated active species and free radicals produced in an aqueous ammonia-ethanol-water solvent. In this report, numerous controlled experiments account for and support the important role of high intensity ultrasounds in the rapid cluster formation, condensation, and gelation process of resorcinol with formaldehyde in the presence of ammonia catalyst. After a controlled heat treatment process, amorphous carbon spheres are obtained from these spherical polymer resins. The effect of temperature (up to 1100 °C) on the structural evolution of these carbon spheres is meticulously studied which is lacking in the previous literature. The resorcinol-formaldehyde resins carbonized at 600 and 900 °C demonstrate BET surface areas of 592.4 m(2)/g and 952.5 m(2)/g with specific capacitances of 17.5, and 33.5 F/g (scan rate of 5 mV/s), respectively. PMID:24914604

  12. Water co-catalyzed selective dehydrogenation of methanol to formaldehyde and hydrogen

    NASA Astrophysics Data System (ADS)

    Shan, Junjun; Lucci, Felicia R.; Liu, Jilei; El-Soda, Mostafa; Marcinkowski, Matthew D.; Allard, Lawrence F.; Sykes, E. Charles H.; Flytzani-Stephanopoulos, Maria

    2016-08-01

    The non-oxidative dehydrogenation of methanol to formaldehyde is considered a promising method to produce formaldehyde and clean hydrogen gas. Although Cu-based catalysts have an excellent catalytic activity in the oxidative dehydrogenation of methanol, metallic Cu is commonly believed to be unreactive for the dehydrogenation of methanol in the absence of oxygen adatoms or oxidized copper. Herein we show that metallic Cu can catalyze the dehydrogenation of methanol in the absence of oxygen adatoms by using water as a co-catalyst both under realistic reaction conditions using silica-supported PtCu nanoparticles in a flow reactor system at temperatures below 250 °C, and in ultra-high vacuum using model PtCu(111) catalysts. Adding small amounts of isolated Pt atoms into the Cu surface to form PtCu single atom alloys (SAAs) greatly enhances the dehydrogenation activity of Cu. Under the same reaction conditions, the yields of formaldehyde from PtCu SAA nanoparticles are more than one order of magnitude higher than on the Cu nanoparticles, indicating a significant promotional effect of individual, isolated Pt atoms. Moreover, this study also shows the unexpected role of water in the activation of methanol. Water, a catalyst for methanol dehydrogenation at low temperatures, becomes a reactant in the methanol steam reforming reactions only at higher temperatures over the same metal catalyst.

  13. Regional sources of atmospheric formaldehyde and acetaldehyde, and implications for atmospheric modeling

    NASA Astrophysics Data System (ADS)

    Luecken, D. J.; Hutzell, W. T.; Strum, M. L.; Pouliot, G. A.

    2012-02-01

    Formaldehyde and acetaldehyde concentrations over the Eastern half of the United States are simulated with a 3-D air quality model to identify the most important chemical precursors under January and July conditions. We find that both aldehydes primarily result from photochemical production, although 25% or more result from direct emissions in urban areas during winter. Isoprene is the major precursor of formaldehyde in most areas during summer, contributing 20-60% of total production, with the magnitude being spatially variable. Other alkenes from anthropogenic and/or biogenic emissions dominate formaldehyde production in winter, contributing 60-85% of total formation, and are prominent contributors in summer. Alkenes, including biogenic alkenes, dominate acetaldehyde production during both seasons. These conclusions are based on the degradation of emitted VOCs described by the SAPRC07TB chemical mechanism, but even this detailed model has difficulty reproducing observed values better than a factor of 2. The substantial role of isoprene and other alkenes in aldehyde formation emphasizes that we examine and improve emission estimates of these compounds. Until we can estimate the emissions and understand the chemistry of VOC precursors to aldehyde formation with greater certainty, it will be difficult to accurately predict atmospheric concentrations of aldehydes and develop strategies to reduce their concentrations.

  14. Enzymic and structural studies on Drosophila alcohol dehydrogenase and other short-chain dehydrogenases/reductases.

    PubMed

    Smilda, T; Kamminga, A H; Reinders, P; Baron, W; van Hylckama Vlieg, J E; Beintema, J J

    2001-05-01

    Enzymic and structural studies on Drosophila alcohol dehydrogenases and other short-chain dehydrogenases/reductases (SDRs) are presented. Like alcohol dehydrogenases from other Drosophila species, the enzyme from D. simulans is more active on secondary than on primary alcohols, although ethanol is its only known physiological substrate. Several secondary alcohols were used to determine the kinetic parameters kcat and Km. The results of these experiments indicate that the substrate-binding region of the enzyme allows optimal binding of a short ethyl side-chain in a small binding pocket, and of a propyl or butyl side-chain in large binding pocket, with stereospecificity for R(-) alcohols. At a high concentration of R(-) alcohols substrate activation occurs. The kcat and Km values determined under these conditions are about two-fold, and two orders of magnitude, respectively, higher than those at low substrate concentrations. Sequence alignment of several SDRs of known, and unknown three-dimensional structures, indicate the presence of several conserved residues in addition to those involved in the catalyzed reactions. Structural roles of these conserved residues could be derived from observations made on superpositioned structures of several SDRs with known structures. Several residues are conserved in tetrameric SDRs, but not in dimeric ones. Two halohydrin-halide-lyases show significant homology with SDRs in the catalytic domains of these enzymes, but they do not have the structural features required for binding NAD+. Probably these lyases descend from an SDR, which has lost the capability to bind NAD+, but the enzyme reaction mechanisms may still be similar. PMID:11443349

  15. Airborne In-Situ Measurements of Formaldehyde over California: First Results from the COFFEE Instrument

    NASA Astrophysics Data System (ADS)

    Marrero, Josette; St. Clair, Jason; Yates, Emma; Swanson, Andrew; Gore, Warren; Iraci, Laura; Hanisco, Thomas

    2016-04-01

    Formaldehyde (HCHO) is one of the most abundant oxygenated volatile organic compounds (VOCs) in the atmosphere, playing a role multiple atmospheric processes. Measurements of HCHO can be used to help quantify convective transport, the abundance of VOCs, and ozone production in urban environments. The Compact Formaldehyde FluorescencE Experiment (COFFEE) instrument uses Non-Resonant Laser Induced Fluorescence (NR-LIF) to detect trace concentrations of HCHO as part of the Alpha Jet Atmospheric eXperiment (AJAX) payload. Developed at NASA GSFC, COFFEE is a small, low maintenance instrument with a sensitivity of 100 pptv and a quick response time (1 sec). The COFFEE instrument has been customized to fit in an external wing pod on the Alpha Jet aircraft based at NASA ARC. The instrument can operate over a broad range of altitudes, from boundary layer to lower stratosphere, making it well suited for the Alpha Jet, which can access altitudes from the surface up to 40,000 ft. We will present results from flights performed over the Central Valley of California, including boundary layer measurements and vertical profiles in the tropospheric column. This region is of particular interest, due to its elevated levels of HCHO, revealed in satellite images, as well as its high ozone concentrations. In addition to HCHO, the AJAX payload includes measurements of atmospheric ozone, methane, and carbon dioxide. These results will be presented in conjunction with formaldehyde. Targets in the Central Valley consist of an oil field, agricultural areas, and highways, each of which can emit HCHO primarily and generate HCHO through secondary production. Formaldehyde is one of the few urban pollutants that can be measured from space. Plans to compare in-situ COFFEE data with satellite-based HCHO observations such as those from OMI (Aura) and OMPS (SuomiNPP) will also be presented.

  16. IRIS Toxicological Review of Formaldehyde (Inhalation) (External Review Draft 2010)

    EPA Science Inventory

    UPDATE EPA is currently revising its Integrated Risk Information System (IRIS) assessment of formaldehyde to address the 2011 NAS peer review recommendations. This assessment addresses both noncancer and cancer human health effects that are relevant to assessing ...

  17. Ion laser isotope enrichment by photo-predissociation of formaldehyde

    DOEpatents

    Marling, John B.

    1977-06-17

    Enrichment of carbon, hydrogen and/or oxygen isotopes by means of isotopically selective photo-predissociation of formaldehyde is achieved by irradiation with a fixed frequency ion laser, specifically, a neon, cadmium, or xenon ion laser.

  18. PHOTOCHEMICAL REACTIONS AMONG FORMALDEHYDE, CHLORINE, AND NITROGEN DIOXIDE IN AIR

    EPA Science Inventory

    Photochemical reactions among chlorine, nitrogen dioxide, and formaldehyde were studied, using parts-per-million concentrations in 1 atm of air. The reactant mixtures were irradiated by ultraviolet fluorescent lamps and simultaneously analyzed by the Fourier transform infrared te...

  19. ETV REPORT: CERTEK, INC. 1414RH FORMALDEHYDE GENERATOR/NEUTRALIZER

    EPA Science Inventory

    The Environmental Technology Verification report discusses the technology and performance of the 1414RH Formaldehyde Generator/Neuralizer, a biological decontamination device manufactured by CERTEK, Inc. The unit was tested by evaluating its ability to decontaminate seven types ...

  20. Formaldehyde Surface Distributions and Variability in the Mexico City Basin

    NASA Astrophysics Data System (ADS)

    Junkermann, W.; Mohr, C.; Steinbrecher, R.; Ruiz Suarez, L.

    2007-05-01

    Formaldehyde ambient air mole fractions were measured throughout the dry season in March at three different locations in the Mexico City basin. The continuously running instruments were operated at Tenago del Aire, a site located in the Chalco valley in the southern venting area of the basin, at the Intituto Mexicano del Petroleo (IMP) in the northern part of the city and about 30 km north of the city at the campus of the Universidad Tecnològica de Tecamac (UTTEC). The technique used is the Hantzsch technology with a time resolution of 2 minutes and a detection limit of 100 ppt. Daily maxima peaked at 35 ppb formaldehyde in the city and about 15 to 20 ppb at the other sites. During night formaldehyde levels dropped to about 5 ppb or less. It is evident that the observed spatial and temporal variability in near surface formaldehyde distributions is strongly affected by local and regional advection processes.

  1. A Density Functional Theory Study of Formaldehyde Adsorption on Ceria

    SciTech Connect

    Mei, Donghai; Deskins, N. Aaron; Dupuis, Michel

    2007-11-01

    Molecular adsorption of formaldehyde on the stoichiometric CeO2(111) and CeO2(110) surfaces was studied using periodic density functional theory. Two adsorption modes (strong chemisorbed and weak physisorbed) were identified on both surfaces. This is consistent with recent experimental observations. On the (111) surface, formaldehyde strongly chemisorbs with an adsorption energy of 0.86 eV to form a dioxymethylene-like structure, in which a surface O lifts from the surface to bind with the C of formaldehyde. A weak physisorbed state with adsorption energy of 0.28 eV was found with the O of formaldehyde interacting with a surface Ce. On the (110) surface, dioxymethyelene formation was also observed, with an adsorption energy of 1.31 eV. The weakly adsorbed state of formaldehyde on the (110) surface was energetically comparable to the weak adsorption state on the (111) surface, but adsorption occurred through a formaldehyde C and surface O interaction. Analysis of the local density of states and charge density differences after adsorption shows that strong covalent bonding occurs between the C of formaldehyde and surface O when dioxymethylene forms. Calculated vibrational frequencies also confirm dioxymethylene formation. Our results also show that as the coverage increases, the adsorption of formaldehyde on the (111) surface becomes weak, but is nearly unaffected on the (110) surface. This work was supported by a Laboratory Directed Research and Development (LDRD) project of the Pacific Northwest National Laboratory (PNNL). The computations were performed using the Molecular Science Computing Facility in the William R. Wiley Environmental Molecular Sciences Laboratory, which is a U.S. Department of Energy national scientific user facility located at PNNL in Richland, Washington. Computing time was made under a Computational Grand Challenge “Computational Catalysis”. Part of the computing time was also granted by the National Energy Research Scientific Computing

  2. Injection Seeded Laser for Formaldehyde Differential Fluorescence Lidar

    NASA Astrophysics Data System (ADS)

    Schwemmer, G.; Yakshin, M.; Prasad, C.; Hanisco, T.; Mylapore, A. R.; Hwang, I. H.; Lee, S.

    2016-06-01

    We describe the design and development of an injection seeded Nd:YVO4 laser for use in a differential fluorescence lidar for measuring atmospheric formaldehyde profiles. A high repetition rate Q-switched laser is modified to accept injection seed input to spectrally narrow and tune the output. The third harmonic output is used to excite formaldehyde (HCHO) fluorescence when tuned to a HCHO absorption line. Spectral confirmation is made with the use of a photoacoustic cell and grating spectrometer.

  3. Betaine aldehyde dehydrogenase in sorghum.

    PubMed Central

    Wood, A J; Saneoka, H; Rhodes, D; Joly, R J; Goldsbrough, P B

    1996-01-01

    The ability to synthesize and accumulate glycine betaine is wide-spread among angiosperms and is thought to contribute to salt and drought tolerance. In plants glycine betaine is synthesized by the two-step oxidation of choline via the intermediate betaine aldehyde, catalyzed by choline monooxygenase and betaine aldehyde dehydrogenase (BADH). Two sorghum (Sorghum bicolor) cDNA clones, BADH1 and BADH15, putatively encoding betaine aldehyde dehydrogenase were isolated and characterized. BADH1 is a truncated cDNA of 1391 bp. BADH15 is a full-length cDNA clone, 1812 bp in length, predicted to encode a protein of 53.6 kD. The predicted amino acid sequences of BADH1 and BADH15 share significant homology with other plant BADHs. The effects of water deficit on BADH mRNA expression, leaf water relations, and glycine betaine accumulation were investigated in leaves of preflowering sorghum plants. BADH1 and BADH15 mRNA were both induced by water deficit and their expression coincided with the observed glycine betaine accumulation. During the course of 17 d, the leaf water potential in stressed sorghum plants reached -2.3 MPa. In response to water deficit, glycine betaine levels increased 26-fold and proline levels increased 108-fold. In severely stressed plants, proline accounted for > 60% of the total free amino acid pool. Accumulation of these compatible solutes significantly contributed to osmotic potential and allowed a maximal osmotic adjustment of 0.405 MPa. PMID:8934627

  4. Formaldehyde Levels in Traditional and Portable Classrooms: A Pilot Investigation.

    PubMed

    Lucas, Isabela Ribeiro; Kowalski, Peter; Callahan, David B; Noonan, Gary P; Moffett, Daphne B; Olson, David H; Malilay, Josephine

    2016-03-01

    The pilot study discussed in this article assessed formaldehyde levels in portable classrooms (PCs) and traditional classrooms the authors evaluated formaldehyde levels in day and overnight indoor air (TCs) and explored factors influencing indoor air quality (e.g., carbon dioxide, temperature, and relative humidity). In a cross-sectional design, samples from nine PCs renovated within three years previously and three TCs in a school district in metropolitan Atlanta, Georgia. Formaldehyde levels ranged from 0.0068 to 0.038 parts per million (ppm). In both types of classroom, overnight formaldehyde median levels (PCs = 0.018 ppm; TCs = 0.019 ppm) were higher than day formaldehyde median levels (PCs = 0.011 ppm; TCs = 0.016 ppm). Carbon dioxide levels measured 470-790 ppm at 7:00 a.m. and 470-1800 ppm at 4:00 p.m. Afternoon medians were higher in TCs (1,400 ppm) than in PCs (780 ppm). Consistent with previous studies, formaldehyde levels were similar among PCs and TCs. Reducing carbon dioxide levels by improving ventilation is recommended for classrooms. PMID:27197349

  5. Formaldehyde emissions from ventilation filters under different relative humidity conditions.

    PubMed

    Sidheswaran, Meera; Chen, Wenhao; Chang, Agatha; Miller, Robert; Cohn, Sebastian; Sullivan, Douglas; Fisk, William J; Kumagai, Kazukiyo; Destaillats, Hugo

    2013-05-21

    Formaldehyde emissions from fiberglass and polyester filters used in building heating, ventilation, and air conditioning (HVAC) systems were measured in bench-scale tests using 10 and 17 cm(2) coupons over 24 to 720 h periods. Experiments were performed at room temperature and four different relative humidity settings (20, 50, 65, and 80% RH). Two different air flow velocities across the filters were explored: 0.013 and 0.5 m/s. Fiberglass filters emitted between 20 and 1000 times more formaldehyde than polyester filters under similar RH and airflow conditions. Emissions increased markedly with increasing humidity, up to 10 mg/h-m(2) at 80% RH. Formaldehyde emissions from fiberglass filters coated with tackifiers (impaction oils) were lower than those from uncoated fiberglass media, suggesting that hydrolysis of other polymeric constituents of the filter matrix, such as adhesives or binders was likely the main formaldehyde source. These laboratory results were further validated by performing a small field study in an unoccupied office. At 80% RH, indoor formaldehyde concentrations increased by 48-64%, from 9-12 μg/m(3) to 12-20 μg/m(3), when synthetic filters were replaced with fiberglass filtration media in the HVAC units. Better understanding of the reaction mechanisms and assessing their overall contributions to indoor formaldehyde levels will allow for efficient control of this pollution source. PMID:23597095

  6. Clinical evaluation of patients with complaints related to formaldehyde exposure

    SciTech Connect

    Imbus, H.R.

    1985-12-01

    Formaldehyde is a very widely used chemical in our present society and one with which every physician has had a first-hand experience in his early days of training in the anatomy laboratory. The National Institute of Occupational Safety and Health lists 52 occupations that expose people to formaldehyde. In recent years, however, the increasing use of formaldehyde resins in the production of building materials such as particleboard and urea-formaldehyde foam insulation has resulted in exposures of large numbers of people in nonoccupational settings. Consumer products such as cosmetics, cigarettes, textiles, furniture, draperies, and preservatives release formaldehyde. It is present in the outdoor atmosphere from products of combustion and automobile exhaust and likewise in the home from such things as gas cooking. These more widespread and increased exposures have resulted in concern regarding potential health effects. Therefore, it is likely that physicians have or will encounter patients who wish evaluations of a present or potential health effect from formaldehyde. This article is for the purpose of providing assistance in such evaluation.110 references.

  7. Histomorphometric comparison after fixation with formaldehyde or glyoxal

    PubMed Central

    Wang, YN; Lee, K; Pai, S; Ledoux, WR

    2014-01-01

    Formaldehyde has long been the fixative of choice for histological examination of tissue. The use of alternatives to formaldehyde has grown, however, owing to the serious hazards associated with its use. Companies have striven to maintain the morphological characteristics of formaldehyde-fixed tissue when developing alternatives. Glyoxal-based fixatives now are among the most popular formaldehyde alternatives. Although there are many studies that compare staining quality and immunoreactivity, there have been no studies that quantify possible structural differences. Histomorphometric analysis commonly is used to evaluate diseased tissue. We compared fixation with formaldehyde and glyoxal with regard to the histomorphological properties of plantar foot tissue using a combination of stereological methods and quantitative morphology. We measured skin thickness, interdigitation index, elastic septa thickness, and adipocyte area and diameter. No significant differences were observed between formaldehyde and glyoxal fixation for any feature measured. The glyoxal-based fixative used therefore is a suitable fixative for structural evaluation of plantar soft tissue. Measurements obtained from the glyoxal-fixed tissue can be combined with data obtained from formalin-fixed for analysis. PMID:20854226

  8. Health risks from indoor formaldehyde exposures in northwest weatherized residences

    SciTech Connect

    Mellinger, P.J.; Sever, L.E.

    1986-10-01

    Conflicting opinions on the potential hazards associated with formaldehyde exposure triggered a national workshop to address the toxicological questions concerning the health effects of formaldehyde. Since quantitative human data are not available to derive a dose-response curve for formaldehyde risk assessment, nonhuman data are used. In the case of formaldehyde, data from animals exposed to high concentrations are used to estimate human risk at much lower concentrations. This study presents the several steps that make up a risk assessment and examines any additional data that might alter significantly the risk estimates presented in the 1984 EIS. Rat inhalation chronic bioassay data from a study sponsored by the Chemical Industry Institute of Toxicology (CIIT) have been used to develop a risk equation that was subsequently used by BPA in its EIS. The CIIT data base remains the only acceptable animal data that can support the estimation of a dose-response curve. The development of mathematical models continues with a great deal of energy, and the use of different models is largely responsible for the great variability of the formaldehyde risk estimates. While one can calculate different values for carcinogenic risk associated with formaldehyde exposure than were presented earlier in the BPA EIS, they are not likely to be any better.

  9. Genotoxic effects in occupational exposure to formaldehyde: A study in anatomy and pathology laboratories and formaldehyde-resins production

    PubMed Central

    2010-01-01

    Background According to the Report on Carcinogens, formaldehyde ranks 25th in the overall U.S. chemical production, with more than 5 million tons produced each year. Given its economic importance and widespread use, many people are exposed to formaldehyde environmentally and/or occupationally. Presently, the International Agency for Research on Cancer classifies formaldehyde as carcinogenic to humans (Group 1), based on sufficient evidence in humans and in experimental animals. Manyfold in vitro studies clearly indicated that formaldehyde can induce genotoxic effects in proliferating cultured mammalian cells. Furthermore, some in vivo studies have found changes in epithelial cells and in peripheral blood lymphocytes related to formaldehyde exposure. Methods A study was carried out in Portugal, using 80 workers occupationally exposed to formaldehyde vapours: 30 workers from formaldehyde and formaldehyde-based resins production factory and 50 from 10 pathology and anatomy laboratories. A control group of 85 non-exposed subjects was considered. Exposure assessment was performed by applying simultaneously two techniques of air monitoring: NIOSH Method 2541 and Photo Ionization Detection equipment with simultaneously video recording. Evaluation of genotoxic effects was performed by application of micronucleus test in exfoliated epithelial cells from buccal mucosa and peripheral blood lymphocytes. Results Time-weighted average concentrations not exceeded the reference value (0.75 ppm) in the two occupational settings studied. Ceiling concentrations, on the other hand, were higher than reference value (0.3 ppm) in both. The frequency of micronucleus in peripheral blood lymphocytes and in epithelial cells was significantly higher in both exposed groups than in the control group (p < 0.001). Moreover, the frequency of micronucleus in peripheral blood lymphocytes was significantly higher in the laboratories group than in the factory workers (p < 0.05). A moderate positive

  10. ATM and KAT5 safeguard replicating chromatin against formaldehyde damage

    PubMed Central

    Ortega-Atienza, Sara; Wong, Victor C.; DeLoughery, Zachary; Luczak, Michal W.; Zhitkovich, Anatoly

    2016-01-01

    Many carcinogens damage both DNA and protein constituents of chromatin, and it is unclear how cells respond to this compound injury. We examined activation of the main DNA damage-responsive kinase ATM and formation of DNA double-strand breaks (DSB) by formaldehyde (FA) that forms histone adducts and replication-blocking DNA-protein crosslinks (DPC). We found that low FA doses caused a strong and rapid activation of ATM signaling in human cells, which was ATR-independent and restricted to S-phase. High FA doses inactivated ATM via its covalent dimerization and formation of larger crosslinks. FA-induced ATM signaling showed higher CHK2 phosphorylation but much lower phospho-KAP1 relative to DSB inducers. Replication blockage by DPC did not produce damaged forks or detectable amounts of DSB during the main wave of ATM activation, which did not require MRE11. Chromatin-monitoring KAT5 (Tip60) acetyltransferase was responsible for acetylation and activation of ATM by FA. KAT5 and ATM were equally important for triggering of intra-S-phase checkpoint and ATM signaling promoted recovery of normal human cells after low-dose FA. Our results revealed a major role of the KAT5-ATM axis in protection of replicating chromatin against damage by the endogenous carcinogen FA. PMID:26420831

  11. Targeting Aldehyde Dehydrogenase 2: New Therapeutic Opportunities

    PubMed Central

    Chen, Che-Hong; Ferreira, Julio Cesar Batista; Gross, Eric R.; Mochly-Rosen, Daria

    2014-01-01

    A family of detoxifying enzymes called aldehyde dehydrogenases (ALDHs) has been a subject of recent interest, as its role in detoxifying aldehydes that accumulate through metabolism and to which we are exposed from the environment has been elucidated. Although the human genome has 19 ALDH genes, one ALDH emerges as a particularly important enzyme in a variety of human pathologies. This ALDH, ALDH2, is located in the mitochondrial matrix with much known about its role in ethanol metabolism. Less known is a new body of research to be discussed in this review, suggesting that ALDH2 dysfunction may contribute to a variety of human diseases including cardiovascular diseases, diabetes, neurodegenerative diseases, stroke, and cancer. Recent studies suggest that ALDH2 dysfunction is also associated with Fanconi anemia, pain, osteoporosis, and the process of aging. Furthermore, an ALDH2 inactivating mutation (termed ALDH2*2) is the most common single point mutation in humans, and epidemiological studies suggest a correlation between this inactivating mutation and increased propensity for common human pathologies. These data together with studies in animal models and the use of new pharmacological tools that activate ALDH2 depict a new picture related to ALDH2 as a critical health-promoting enzyme. PMID:24382882

  12. [Cooperative properties of D-glyceraldehyde-3-phosphate dehydrogenase].

    PubMed

    Nagradova, N K

    1977-03-01

    The structure of the active center of glyceraldehyde-3-phosphate dehydrogenase and the arrangement of subunits in the tetrameric molecule is delineated. The mechanism of cooperative effects in the oligomer is considered, and the involvement of various regions of the active center and of different-subunit contact area in the realization of the cooperative phenomena is discussed. A special attention is paid to the effect of NAD+ bound to one of the subunits of the tetramer on the structure of an adjacent subunit and to the problem of the participation of the coenzyme in the creation of anion-binding sites of the enzyme. The conditions of reversible dissociation of the tetrameric apoenzyme molecule into dimers are depicted, and the role of NAD+ in the organization of the quaternary structure of the dehydrogenase is discussed. The problem of catalytic activity of the dimeric form of the enzyme is argued. PMID:193581

  13. Single motoneuron succinate dehydrogenase activity.

    PubMed

    Chalmers, G R; Edgerton, V R

    1989-07-01

    We have developed a quantitative histochemical assay for measurement of succinate dehydrogenase (SDH) activity in single motoneurons. A computer image processing system was used to quantify the histochemical enzyme reaction product and to follow the time course of the reaction. The optimal concentration for each of the ingredients of the incubation medium for the SDH reaction was determined and the importance of using histochemical "blanks" in the determination of enzymatic activity was demonstrated. The enzymatic activity was linear with respect to reaction time and tissue thickness. The procedure described meets the criteria generally considered essential for establishment of a quantitative histochemical assay. The assay was then used to examine the SDH activity of cat and rat motoneurons. It was found that motoneurons with a small soma size had a wide range of SDH activity, whereas those with a large soma size were restricted to low SDH activity. PMID:2732457

  14. Airborne tunable diode laser measurements of formaldehyde

    NASA Astrophysics Data System (ADS)

    Fried, Alan; Wert, Bryan P.; Henry, Bruce; Drummond, James R.

    1999-09-01

    Accurate measurements of formaldehyde (CH 2O) in the atmosphere are essential to further our understanding of various atmospheric cycles involving hydrogen and carbon-containing species. Comparisons among independent measurements of this gas and between measurements and model calculations have raised numerous questions regarding the veracity of both endeavors. The present paper describes a long-term effort by our group to develop and employ tunable diode laser absorption spectroscopy (TDLAS) for highly accurate measurements of this gas on both ground-based and aircraft platforms. A highly sensitive and selective TDLAS system, which has successfully flown on three different aircraft campaigns, will be described. Many new hardware and software features, which have been implemented, now make it possible to detect ambient CH 2O concentrations as low as 55 parts-per-trillion employing a 20-s integration time. This paper will also discuss the many aspects associated with high accuracy and its verification, including a brief discussion of our aircraft sampling system and inlet surface effects.

  15. Resorcinol-formaldehyde and carbon aerogel microspheres

    SciTech Connect

    Alviso, C.T.; Pekela, R.W.; Gross, J.; Lu, X.; Caps, R.; Fricke, J

    1996-04-01

    Aerogels are a unique class of materials possessing an open-cell structure with ultrafine cells/pores (<100nm), high surface area (400--1100 m{sup 2}/g), and a solid matrix composed of interconnected particles, fibers, or platelets with characteristic dimensions of 10nm. Although monolithic aerogels are ideal candidates for many applications (e.g. transparent window insulation), current processing methods have limited their introduction into the commercial marketplace. Our research focuses on the formation of resorcinol-formaldehyde (RF) aerogel microspheres which offer an attractive alternative to monolith production. An inverse emulsion polymerization is used to produce these spherical gel particles which undergo solvent exchange followed by supercritical drying with carbon dioxide. This process yields aerogel microspheres (10--80{mu} diameter) which can be used as loosely packed powders, compression molded into near-net shapes using a polymer binder, or used as additives in conventional foaming operations to produce new aerogel composites with superior thermal properties. The emulsification procedure, thermal characterization, mechanical properties, and potential applications of RF aerogel microspheres will be discussed.

  16. Chronic respiratory effects of indoor formaldehyde exposure

    SciTech Connect

    Krzyzanowski, M.; Quackenboss, J.J.; Lebowitz, M.D. )

    1990-08-01

    The relation of chronic respiratory symptoms and pulmonary function to formaldehyde (HCHO) in homes was studied in a sample of 298 children (6-15 years of age) and 613 adults. HCHO measurements were made with passive samplers during two 1-week periods. Data on chronic cough and phlegm, wheeze, attacks of breathlessness, and doctor diagnoses of chronic bronchitis and asthma were collected with self-completed questionnaires. Peak expiratory flow rates (PEFR) were obtained during the evenings and mornings for up to 14 consecutive days for each individual. Significantly greater prevalence rates of asthma and chronic bronchitis were found in children from houses with HCHO levels 60-120 ppb than in those less exposed, especially in children also exposed to environmental tobacco smoke. In children, levels of PEFR decreased linearly with HCHO exposure, with the estimated decrease due to 60 ppb of HCHO equivalent to 22% of PEFR level in nonexposed children. The effects in asthmatic children exposed to HCHO below 50 ppb were greater than in healthy ones. The effects in adults were less evident: decrements in PEFR due to HCHO over 40 ppb were seen only in the morning, and mainly in smokers.

  17. Passive flux sampler for measurement of formaldehyde emission rates

    NASA Astrophysics Data System (ADS)

    Shinohara, Naohide; Fujii, Minoru; Yamasaki, Akihiro; Yanagisawa, Yukio

    A new passive flux sampler (PFS) was developed to measure emission rates of formaldehyde and to determine emission sources in indoor environments. The sampler consisted of a glass Petri dish containing a 2,4-dinitrophenyl hydrazine (DNPH)-impregnated sheet. At the start of sampling, the PFS was placed with the open face of the dish on each of the indoor materials under investigation, such as flooring, walls, doors, closets, desks, beds, etc. Formaldehyde emitted from a source material diffused through the inside of the PFS and was adsorbed onto the DNPH sheet. The formaldehyde emission rates could be determined from the quantities adsorbed. The lower determination limits were 9.2 and 2.3 μg m -2 h -1 for 2- and 8-h sampling periods. The recovery rate and the precision of the PFS were 82.9% and 8.26%, respectively. The emission rates measured by PFS were in good agreement with the emission rates measured by the chamber method ( R2=0.963). This shows that it is possible to take measurements of the formaldehyde emission rates from sources in a room and to compare them. In addition, the sampler can be used to elucidate the emission characteristics of a source by carrying out emission measurements with different air-layer thicknesses inside the PFS and at different temperatures. The dependency of the emission rate on the thickness of the air layer inside the PFS indicated whether the internal mass transfer inside the source material or the diffusion in the gas-phase boundary layer controlled the formaldehyde emission rate from a material. In addition, as a pilot study, the formaldehyde emission rates were measured, and the largest emission source of formaldehyde could be identified from among several suspected materials in a model house by using the PFS.

  18. Mechanisms of mutagenesis: Analysis through the use of alcohol dehydrogenase in Drosophila: Final report

    SciTech Connect

    Sofer, W.H.

    1986-12-01

    Our original objective was to understand the mechanism of mutagenesis of several important mutagens in higher organisms. Our approach was to try to deduce this mechanism by working backwards from its final effects. The strategy that we used in an effort to carry out our studies was to make mutations in the alcohol dehydrogenase gene of Drosophila melanogaster and sequence the modified genes. Most of our work was focused on an array of mutants that we had induced with formaldehyde, a potent mutagen in Drosophila, and with ethyl methane sulfonate. Over the course of the project period we cloned and sequenced the ADH gene from four formalde-induced mutants and from one EMS mutant. We showed that the four formaldehyde-induced mutants contained small deletions within the protein-coding region of their ADH genes ranging in size from between 6 and 34 bp. The one EMS-induced mutant was shown by DNA sequencing to bear an AT to GC sequence change at a tryptophan codon near the c-terminal coding portion of the gene. These results have significantly increased our understanding of the mechanism(s) of mutagenesis in higher organisms. 20 refs., 1 fig.

  19. Formaldehyde emission—Comparison of different standard methods

    NASA Astrophysics Data System (ADS)

    Risholm-Sundman, Maria; Larsen, Annelise; Vestin, Ewa; Weibull, Anders

    The emission of formaldehyde is an important factor in the evaluation of the environmental and health effects of wood-based board materials. This article gives a comparison between commonly used European test methods: chamber method [EN 717-1, 2004. Wood-based panels—determination of formaldehyde release—Part 1: formaldehyde emission by the chamber method. European Standard, October 2004], gas analysis method [EN 717-2, 1994. Wood-based panels—determination of formaldehyde release—Part 2: formaldehyde release by the gas analysis method, European Standard, November 1994], flask method [EN 717-3, 1996. Wood-based panels—determination of formaldehyde release—Part 3: formaldehyde release by the flask method, European Standard, March 1996], perforator method [EN 120, 1993. Wood based panels—determination of formaldehyde content—extraction method called perforator method, European Standard, September 1993], Japanese test methods: desiccator methods [JIS A 1460, 2001. Building boards. Determination of formaldehyde emission—desiccator method, Japanese Industrial Standard, March 2001 and JAS MAFF 233, 2001] and small chamber method [JIS A 1901, 2003. Determination of the emission of volatile organic compounds and aldehydes for building products—small chamber method, Japanese Industrial Standard, January 2003], for solid wood, particleboard, plywood and medium density fiberboard. The variations between the results from different methods can partly be explained by differences in test conditions. Factors like edge sealing, conditioning of the sample before the test and test temperature have a large effect on the final emission result. The Japanese limit for F **** of 0.3 mg l -1 (in desiccator) for particleboards was found to be equivalent to 0.04 mg m -3 in the European chamber test and 2.8 mg per 100 g in the perforator test. The variations in inter-laboratory tests are much larger than in intra-laboratory tests; the coefficient of variation is 16% and 6

  20. Comparison of ozone and formaldehyde as poultry hatchery disinfectants

    SciTech Connect

    Whistler, P.E.; Sheldon, B.W. )

    1989-10-01

    Ozone and formaldehyde were compared as poultry hatchery disinfectants in a poultry setter, and evaluated for effectiveness. Escherichia coli, Pseudomonas fluorescens, Salmonella typhimurium, and Proteus spp. were inoculated onto open petri plates and exposed to ozone or onto filter paper strips and exposed to ozone or formaldehyde in a poultry setter. Ozone (1.41 to 1.68% by weight) resulted in significant bacterial reductions of greater than 4 log10 on the open plates and greater than 3 log10 on filter paper strips, whereas formaldehyde (triple strength) resulted in greater than 7 log10 reduction on filter paper strips. Ozone was similarly lethal to organisms on filter paper strips at 90% relative humidity (RH) and 13.9 C, and at 50% RH and 37.7 C. Although under the conditions of this study formaldehyde (triple strength) was more lethal than ozone, ozone killed greater than 99.9% of the starting microbial populations. In the event that formaldehyde can no longer be used in the hatchery, an effective alternative may be ozone.

  1. Formaldehyde as a basis for residential ventilation rates

    SciTech Connect

    Sherman, M.H.; Hodgson, A.T.

    2002-04-28

    Traditionally, houses in the U.S. have been ventilated by passive infiltration in combination with active window opening. However in recent years, the construction quality of residential building envelopes has been improved to reduce infiltration, and the use of windows for ventilation also may have decreased due to a number of factors. Thus, there has been increased interest in engineered ventilation systems for residences. The amount of ventilation provided by an engineered system should be set to protect occupants from unhealthy or objectionable exposures to indoor pollutants, while minimizing energy costs for conditioning incoming air. Determining the correct ventilation rate is a complex task, as there are numerous pollutants of potential concern, each having poorly characterized emission rates, and poorly defined acceptable levels of exposure. One ubiquitous pollutant in residences is formaldehyde. The sources of formaldehyde in new houses are reasonably understood, and there is a large body of literature on human health effects. This report examines the use of formaldehyde as a means of determining ventilation rates and uses existing data on emission rates of formaldehyde in new houses to derive recommended levels. Based on current, widely accepted concentration guidelines for formaldehyde, the minimum and guideline ventilation rates for most new houses are 0.28 and 0.5 air changes per hour, respectively.

  2. [Disinfection and sterilization of thermolabile instruments with gaseous formaldehyde].

    PubMed

    Mecke, P

    1984-12-01

    For several years formaldehyde-gas-underpressure procedures are increasingly used for disinfection and sterilization of medical thermolabile instruments. In many places, however, uncertainty and sceptism, if these methods are sufficient in the medical field, are existing. This is understandable, since no generally test instructions are available. The principal suitability of gaseous formaldehyde for disinfection and sterilization, however, had been demonstrated by several investigators. Precondition for reliable efficacy during routine use is an apparatus which is equipped with feed-back techniques and which guarantees the bactericidal and fungicidal activity required for medical use. Decontamination procedures on the basis of gaseous formaldehyde under normal conditions of temperature and pressure must be regarded as unsafe. St. faecalis and the spores of B. stearothermophilus showed the highest formaldehyde resistance within the group of common biological testorganisms. In order to test the efficacy of corresponding procedures testorganisms have to be placed into testdevices with small lumina. The penetration of these devices to formaldehyde and vapour should be similar to that of the longest instruments with the smallest lumina, which are intended to be decontaminated by the testprocedure. PMID:6442506

  3. Comparison of ozone and formaldehyde as poultry hatchery disinfectants.

    PubMed

    Whistler, P E; Sheldon, B W

    1989-10-01

    Ozone and formaldehyde were compared as poultry hatchery disinfectants in a poultry setter, and evaluated for effectiveness. Escherichia coli, Pseudomonas fluorescens, Salmonella typhimurium, and Proteus spp. were inoculated onto open petri plates and exposed to ozone or onto filter paper strips and exposed to ozone or formaldehyde in a poultry setter. Ozone (1.41 to 1.68% by weight) resulted in significant bacterial reductions of greater than 4 log10 on the open plates and greater than 3 log10 on filter paper strips, whereas formaldehyde (triple strength) resulted in greater than 7 log10 reduction on filter paper strips. Ozone was similarly lethal to organisms on filter paper strips at 90% relative humidity (RH) and 13.9 C, and at 50% RH and 37.7 C. Although under the conditions of this study formaldehyde (triple strength) was more lethal than ozone, ozone killed greater than 99.9% of the starting microbial populations. In the event that formaldehyde can no longer be used in the hatchery, an effective alternative may be ozone. PMID:2511564

  4. FORMALDEHYDE GAS INACTIVATION OF BACILLUS ANTHRACIS, BACILLUS SUBTILIS AND GEOBACILLUS STEAROTHERMOPHILUS SPORES ON INDOOR SURFACE MATERIALS.

    EPA Science Inventory

    Research evaluated the decontamination of Bacillus anthracis, Bacillus subtilis, and Geobacillus stearothermophilus spores on indoor surface material using formaldehyde gas. Spores were dried on seven types of indoor surfaces and exposed to 1100 ppm formaldehyde gas for 10 hr. Fo...

  5. Systematic review of the epidemiology literature on formaldehyde and cancers of the upper respiratory tract

    EPA Science Inventory

    Background: EPA is currently drafting a Toxicological Review of formaldehyde. As part of the comprehensive evaluation of potential hazards associated with exposure to formaldehyde, the potential hazards for cancers of the upper respiratory tract are being evaluated. We are aware ...

  6. Systematic review of the epidemiology literature on formaldehyde and lymphohematopoietic cancers

    EPA Science Inventory

    Background: EPA is currently drafting a Toxicological Review of formaldehyde. As part of the comprehensive evaluation of potential hazards associated with exposure to formaldehyde, the potential hazards for lymphohematopoietic cancers are being evaluated. We are aware of multiple...

  7. 24 CFR 3280.308 - Formaldehyde emission controls for certain wood products.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ...-to-urea ratio is increased; (B) The amount of formaldehyde resin used is increased; or (C) The press... formaldehyde-to-urea ratio is increased; or (ii) In the case of particleboard or plywood, the finishing or...

  8. 24 CFR 3280.308 - Formaldehyde emission controls for certain wood products.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ...-to-urea ratio is increased; (B) The amount of formaldehyde resin used is increased; or (C) The press... formaldehyde-to-urea ratio is increased; or (ii) In the case of particleboard or plywood, the finishing or...

  9. 24 CFR 3280.308 - Formaldehyde emission controls for certain wood products.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ...-to-urea ratio is increased; (B) The amount of formaldehyde resin used is increased; or (C) The press... formaldehyde-to-urea ratio is increased; or (ii) In the case of particleboard or plywood, the finishing or...

  10. Amended safety assessment of formaldehyde and methylene glycol as used in cosmetics.

    PubMed

    Boyer, Ivan J; Heldreth, Bart; Bergfeld, Wilma F; Belsito, Donald V; Hill, Ronald A; Klaassen, Curtis D; Liebler, Daniel C; Marks, James G; Shank, Ronald C; Slaga, Thomas J; Snyder, Paul W; Andersen, F Alan

    2013-01-01

    Formaldehyde and methylene glycol may be used safely in cosmetics if established limits are not exceeded and are safe for use in nail hardeners in the present practices of use and concentration, which include instructions to avoid skin contact. In hair-smoothing products, however, in the present practices of use and concentration, formaldehyde and methylene glycol are unsafe. Methylene glycol is continuously converted to formaldehyde, and vice versa, even at equilibrium, which can be easily shifted by heating, drying, and other conditions to increase the amount of formaldehyde. This rapid, reversible formaldehyde/methylene glycol equilibrium is distinguished from the slow, irreversible release of formaldehyde resulting from the so-called formaldehyde releaser preservatives, which are not addressed in this safety assessment (formaldehyde releasers may continue to be safely used in cosmetics at the levels established in their individual Cosmetic Ingredient Review safety assessments). PMID:24335968

  11. Formaldehyde and hydroperoxides at Mauna Loa Observatory

    SciTech Connect

    Heikes, B.G. )

    1992-11-20

    Hydrogen peroxide, formaldehyde, and a measure of organic hydroperoxides are presented from the Mauna Loa Observatory Photochemistry Experiment (MLOPEX). MLOPEX was conducted from May 1 to June 4, 1988, at the Mauna Loa Observatory on the island of Hawaii. A modified dual-enzyme serial-coil H[sub 2]O[sub 2]/ROOH method was used to quantify these species. A second enzyme method was used to measure CH[sub 2]O. The location and meteorology at the Mauna Loa Observatory site permitted 35 days of measurements to be made in free tropospheric air and in modified marine boundary layer air. Average concentrations of H[sub 2]O[sub 2], ROOH, and CH[sub 2]O were 1050, 140, and 100 pptv in free tropospheric, or down-slope air. In upslope air, or modified marine boundary layer air, average concentrations were 900, 150, and 190 pptv. Maximum concentrations for all three species were experienced during a two day photochemical haze episode and were 3230, 440, and 450 pptv for H[sub 2]O[sub 2], ROOH, and CH[sub 2]O. H[sub 2]O[sub 2] was depleted in air which had recently been processed by cloud or precipitation. The measured concentrations of these three species were comparable to prior measurements in well- aged air, but were lower than previous models have predicted. Part of this discrepancy may be due to the treatment of heterogeneous removal processes, dry and wet deposition, in these models. The measured ratio of ROOH to H[sub 2]O[sub 2] is significantly different than present theory predicts, with ROOH as measured being approximately a factor of 5 too low. 61 refs., 13 figs., 2 tabs.

  12. Targeting isocitrate dehydrogenase (IDH) in cancer.

    PubMed

    Fujii, Takeo; Khawaja, Muhammad Rizwan; DiNardo, Courtney D; Atkins, Johnique T; Janku, Filip

    2016-05-01

    Isocitrate dehydrogenase (IDH) is an essential enzyme for cellular respiration in the tricarboxylic acid (TCA) cycle. Recurrent mutations in IDH1 or IDH2 are prevalent in several cancers including glioma, acute myeloid leukemia (AML), cholangiocarcinoma and chondrosarcoma. The mutated IDH1 and IDH2 proteins have a gain-of-function, neomorphic activity, catalyzing the reduction of α-ketoglutarate (α-KG) to 2-hydroxyglutarate (2-HG) by NADPH. Cancer-associated IDH mutations block normal cellular differentiation and promote tumorigenesis via the abnormal production of the oncometabolite 2-HG. High levels of 2-HG have been shown to inhibit α-KG dependent dioxygenases, including histone and deoxyribonucleic acid (DNA) demethylases, which play a key role in regulating the epigenetic state of cells. Current targeted inhibitors of IDH1 (AG120, IDH305), IDH2 (AG221), and pan-IDH1/2 (AG881) selectively inhibit mutant IDH protein and induce cell differentiation in in vitro and in vivo models. Preliminary results from phase I clinical trials with IDH inhibitors in patients with advanced hematologic malignancies have demonstrated an objective response rate ranging from 31% to 40% with durable responses (>1 year) observed. Furthermore, the IDH inhibitors have demonstrated early signals of activity in solid tumors with IDH mutations, including cholangiocarcinomas and low grade gliomas. PMID:27355333

  13. Eucalypt NADP-Dependent Isocitrate Dehydrogenase1

    PubMed Central

    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

  14. Functional Analysis of a Mosquito Short Chain Dehydrogenase Cluster

    PubMed Central

    Mayoral, Jaime G.; Leonard, Kate T.; Defelipe, Lucas A.; Turjansksi, Adrian G.; Nouzova, Marcela; Noriegal, Fernando G.

    2013-01-01

    The short chain dehydrogenases (SDR) constitute one the oldest and largest families of enzymes with over 46,000 members in sequence databases. About 25% of all known dehydrogenases belong to the SDR family. SDR enzymes have critical roles in lipid, amino acid, carbohydrate, hormone and xenobiotic metabolism as well as in redox sensor mechanisms. This family is present in archaea, bacteria, and eukaryota, emphasizing their versatility and fundamental importance for metabolic processes. We identified a cluster of eight SDRs in the mosquito Aedes aegypti (AaSDRs). Members of the cluster differ in tissue specificity and developmental expression. Heterologous expression produced recombinant proteins that had diverse substrate specificities, but distinct from the conventional insect alcohol (ethanol) dehydrogenases. They are all NADP+-dependent and they have S-enantioselectivity and preference for secondary alcohols with 8–15 carbons. Homology modeling was used to build the structure of AaSDR1 and two additional cluster members. The computational study helped explain the selectivity towards the (10S)-isomers as well as the reduced activity of AaSDR4 and AaSDR9 for longer isoprenoid substrates. Similar clusters of SDRs are present in other species of insects, suggesting similar selection mechanisms causing duplication and diversification of this family of enzymes. PMID:23238893

  15. A Cluster of Four Homologous Small RNAs Modulates C1 Metabolism and the Pyruvate Dehydrogenase Complex in Rhodobacter sphaeroides under Various Stress Conditions

    PubMed Central

    Billenkamp, Fabian; Peng, Tao; Berghoff, Bork A.

    2015-01-01

    ABSTRACT In bacteria, regulatory RNAs play an important role in the regulation and balancing of many cellular processes and stress responses. Among these regulatory RNAs, trans-encoded small RNAs (sRNAs) are of particular interest since one sRNA can lead to the regulation of multiple target mRNAs. In the purple bacterium Rhodobacter sphaeroides, several sRNAs are induced by oxidative stress. In this study, we focused on the functional characterization of four homologous sRNAs that are cotranscribed with the gene for the conserved hypothetical protein RSP_6037, a genetic arrangement described for only a few sRNAs until now. Each of the four sRNAs is characterized by two stem-loops that carry CCUCCUCCC motifs in their loops. They are induced under oxidative stress, as well as by various other stress conditions, and were therefore renamed here sRNAs CcsR1 to CcsR4 (CcsR1–4) for conserved CCUCCUCCC motif stress-induced RNAs 1 to 4. Increased CcsR1–4 expression decreases the expression of genes involved in C1 metabolism or encoding components of the pyruvate dehydrogenase complex either directly by binding to their target mRNAs or indirectly. One of the CcsR1–4 target mRNAs encodes the transcriptional regulator FlhR, an activator of glutathione-dependent methanol/formaldehyde metabolism. Downregulation of this glutathione-dependent pathway increases the pool of glutathione, which helps to counteract oxidative stress. The FlhR-dependent downregulation of the pyruvate dehydrogenase complex reduces a primary target of reactive oxygen species and reduces aerobic electron transport, a main source of reactive oxygen species. Our findings reveal a previously unknown strategy used by bacteria to counteract oxidative stress. IMPORTANCE Phototrophic organisms have to cope with photo-oxidative stress due to the function of chlorophylls as photosensitizers for the formation of singlet oxygen. Our study assigns an important role in photo-oxidative stress resistance to a

  16. Health effects of low-level exposure to formaldehyde

    SciTech Connect

    Main, D.M.; Hogan, T.J.

    1983-12-01

    Twenty-one subjects exposed to formaldehyde (at levels between 0.12 and 1.6 parts per million (ppm)) in two mobile trailers and the remaining 18 unexposed workers of the same workforce were examined by questionnaire and spirometry. Symptoms of eye and throat irritation and increased headache and fatigue were significantly more common among the exposed group than the comparison group. Irritation of the nose, chest tightness, and shortness of breath were also more common among the exposed. Spirometry revealed no decrease in ventilatory function among the exposed workers. The significant increase in frequency of individuals with symptoms indicated an adverse health effect from exposure to formaldehyde at levels between 0.12 and 1.6 ppm. This may have implications regarding the adequacy of the US permissable exposure limit value and suggest the need for further examination of the health effects of formaldehyde in the nonoccupational environment.

  17. Formaldehyde Concentration Dynamics of the International Space Station Cabin Atmosphere

    NASA Technical Reports Server (NTRS)

    Perry, J. L.

    2005-01-01

    Formaldehyde presents a significant challenge to maintaining cabin air quality on board crewed spacecraft. Generation sources include offgassing from a variety of non-metallic materials as well as human metabolism. Because generation sources are pervasive and human health can be affected by continual exposure to low concentrations, toxicology and air quality control engineering experts jointly identified formaldehyde as a key compound to be monitored as part the International Space Station's (ISS) environmental health monitoring and maintenance program. Data acquired from in-flight air quality monitoring methods are the basis for assessing the cabin environment's suitability for long-term habitation and monitoring the performance of passive and active controls that are in place to minimize crew exposure. Formaldehyde concentration trends and dynamics served in the ISS cabin atmosphere are reviewed implications to present and future flight operations discussed.

  18. Evaluation of a low-temperature steam and formaldehyde sterilizer.

    PubMed

    Kanemitsu, K; Kunishima, H; Imasaka, T; Ishikawa, S; Harigae, H; Yamato, S; Hirayama, Y; Kaku, M

    2003-09-01

    We evaluated a low-temperature steam and formaldehyde (LTSF) sterilizer based on the draft European Standard prEN 14180. Microbiological tests were conducted on small and full loads using process challenge devices in five programs (P1-P5). With small loads all tests showed no growth of Bacillus stearothermophilus (ATCC7953) spores. However, positive cultures were observed with full-load tests using P5 (sterilization temperature, 50 degrees C). Our data indicated that the load influenced the efficacy of the LTSF sterilizer. Desorption tests were conducted to determine residual formaldehyde in indicator strips. The mean concentrations of formaldehyde in P1-P5 were 31.9, 56.3, 54.9, 82.2 and 180.6 microg, respectively, which are below the limits allowed by the draft Standard. Our results indicate that the LTSF sterilizer is useful for sterilization because of its excellent efficacy, short handling time, and safety. PMID:14505609

  19. Formaldehyde--study of indoor air pollution in Austria.

    PubMed

    Koeck, M; Pichler-Semmelrock, F P; Schlacher, R

    1997-09-01

    As part of a long-term study of indoor air pollution, formaldehyde concentrations were determined in 792 apartments following complaints by inhabitants. Measurements were carried out using Draeger tubes as well as the acetyl acetone method. In 157 apartments, HCHO concentrations of more than 0.1 ppm, exceeding the recommended standard values for indoor air concentrations, were determined. The concentrations determined tended to decrease over time. As far as they were caused by furnishings, they were limited to the spaces where these furnishings were installed. In older-style prefabricated houses with foam-filled particle-board wall systems, concentrations of more than 1.0 ppm were determined. In spite of legal regulations governing the release of formaldehyde from substances, preparations and products containing formaldehyde which have been in existence in Austria since 1990, this substance must still be considered as a possible factor of indoor pollution in causing feelings of ill-health. PMID:9386898

  20. Studies on adsorption of formaldehyde in zirconium phosphate-glyphosates

    NASA Astrophysics Data System (ADS)

    Zhang, Yuejuan; Yi, Jianjun; Xu, Qinghong

    2011-01-01

    In our previous work [22], a kind of layered compound of zirconium phosphate-glyphosate (ZrGP) was synthesized. Its large surface area (445 m 2/g) indicates this compound has possible application in adsorptions. In this paper, adsorption to formaldehyde in ZrGP and mechanisms of the adsorption were studied carefully. Balance time of adsorption (about 6 h) and largest adsorbed amount (7.8%) were found when adsorption temperature was at 40 °C and pH value of adsorption environment was about 3.0. H-bonds were found existing between molecules of formaldehyde and ZrGP, and formaldehyde molecules could exist in ZrGP stably.

  1. Biochemical and Structural Studies of Uncharacterized Protein PA0743 from Pseudomonas aeruginosa Revealed NAD+-dependent l-Serine Dehydrogenase*

    PubMed Central

    Tchigvintsev, Anatoli; Singer, Alexander; Brown, Greg; Flick, Robert; Evdokimova, Elena; Tan, Kemin; Gonzalez, Claudio F.; Savchenko, Alexei; Yakunin, Alexander F.

    2012-01-01

    The β-hydroxyacid dehydrogenases form a large family of ubiquitous enzymes that catalyze oxidation of various β-hydroxy acid substrates to corresponding semialdehydes. Several known enzymes include β-hydroxyisobutyrate dehydrogenase, 6-phosphogluconate dehydrogenase, 2-(hydroxymethyl)glutarate dehydrogenase, and phenylserine dehydrogenase, but the vast majority of β-hydroxyacid dehydrogenases remain uncharacterized. Here, we demonstrate that the predicted β-hydroxyisobutyrate dehydrogenase PA0743 from Pseudomonas aeruginosa catalyzes an NAD+-dependent oxidation of l-serine and methyl-l-serine but exhibits low activity against β-hydroxyisobutyrate. Two crystal structures of PA0743 were solved at 2.2–2.3-Å resolution and revealed an N-terminal Rossmann fold domain connected by a long α-helix to the C-terminal all-α domain. The PA0743 apostructure showed the presence of additional density modeled as HEPES bound in the interdomain cleft close to the predicted catalytic Lys-171, revealing the molecular details of the PA0743 substrate-binding site. The structure of the PA0743-NAD+ complex demonstrated that the opposite side of the enzyme active site accommodates the cofactor, which is also bound near Lys-171. Site-directed mutagenesis of PA0743 emphasized the critical role of four amino acid residues in catalysis including the primary catalytic residue Lys-171. Our results provide further insight into the molecular mechanisms of substrate selectivity and activity of β-hydroxyacid dehydrogenases. PMID:22128181

  2. Genetics Home Reference: succinic semialdehyde dehydrogenase deficiency

    MedlinePlus

    ... a chemical that transmits signals in the brain (neurotransmitter) called gamma-amino butyric acid (GABA). The primary ... Diseases National Organization for Rare Disorders (NORD) Pediatric Neurotransmitter Disease Association GeneReviews (1 link) Succinic Semialdehyde Dehydrogenase ...

  3. Hydroxysteroid dehydrogenases (HSDs) in bacteria: a bioinformatic perspective.

    PubMed

    Kisiela, Michael; Skarka, Adam; Ebert, Bettina; Maser, Edmund

    2012-03-01

    Steroidal compounds including cholesterol, bile acids and steroid hormones play a central role in various physiological processes such as cell signaling, growth, reproduction, and energy homeostasis. Hydroxysteroid dehydrogenases (HSDs), which belong to the superfamily of short-chain dehydrogenases/reductases (SDR) or aldo-keto reductases (AKR), are important enzymes involved in the steroid hormone metabolism. HSDs function as an enzymatic switch that controls the access of receptor-active steroids to nuclear hormone receptors and thereby mediate a fine-tuning of the steroid response. The aim of this study was the identification of classified functional HSDs and the bioinformatic annotation of these proteins in all complete sequenced bacterial genomes followed by a phylogenetic analysis. For the bioinformatic annotation we constructed specific hidden Markov models in an iterative approach to provide a reliable identification for the specific catalytic groups of HSDs. Here, we show a detailed phylogenetic analysis of 3α-, 7α-, 12α-HSDs and two further functional related enzymes (3-ketosteroid-Δ(1)-dehydrogenase, 3-ketosteroid-Δ(4)(5α)-dehydrogenase) from the superfamily of SDRs. For some bacteria that have been previously reported to posses a specific HSD activity, we could annotate the corresponding HSD protein. The dominating phyla that were identified to express HSDs were that of Actinobacteria, Proteobacteria, and Firmicutes. Moreover, some evolutionarily more ancient microorganisms (e.g., Cyanobacteria and Euryachaeota) were found as well. A large number of HSD-expressing bacteria constitute the normal human gastro-intestinal flora. Another group of bacteria were originally isolated from natural habitats like seawater, soil, marine and permafrost sediments. These bacteria include polycyclic aromatic hydrocarbons-degrading species such as Pseudomonas, Burkholderia and Rhodococcus. In conclusion, HSDs are found in a wide variety of microorganisms including

  4. Structural Basis for "Flip-Flop" Action of Human Pyruvate Dehydrogenase

    NASA Technical Reports Server (NTRS)

    Ciszak, Ewa; Korotchkina, Lioubov; Dominiak, Paulina; Sidhu, Sukhdeep; Patel, Mulchand

    2003-01-01

    The derivative of vitamin B1, thiamin pyrophosphate is a cofactor of pyruvate dehydrogenase, a component enzyme of the mitochondrial pyruvate dehydrogenase multienzyme complex that plays a major role in directing energy metabolism in the cell. This cofactor is used to cleave the C(sup alpha)-C(=O) bond of pyruvate followed by reductive acetyl transfer to lipoyl-dihydrolipoamide acetyltransferase. In alpha(sub 2)beta(sub 2)-tetrameric human pyruvate dehydrogenase, there are two cofactor binding sites, each of them being a center of independently conducted, although highly coordinated enzymatic reactions. The dynamic nonequivalence of two, otherwise chemically equivalent, catalytic sites can now be understood based on the recently determined crystal structure of the holo-form of human pyruvate dehydrogenase at 1.95A resolution. The structure of pyruvate dehydrogenase was determined using a combination of MAD phasing and molecular replacement followed by rounds of torsion-angles molecular-dynamics simulated-annealing refinement. The final pyruvate dehydrogenase structure included coordinates for all protein amino acids two cofactor molecules, two magnesium and two potassium ions, and 742 water molecules. The structure was refined to R = 0.202 and R(sub free) = 0.244. Our structural analysis of the enzyme folding and domain assembly identified a simple mechanism of this protein motion required for the conduct of catalytic action.

  5. Reproductive and Developmental Toxicity of Formaldehyde: A Systematic Review

    PubMed Central

    Duong, Anh; Steinmaus, Craig; McHale, Cliona M.; Vaughan, Charles P.; Zhang, Luoping

    2011-01-01

    Formaldehyde, the recently classified carcinogen and ubiquitous environmental contaminant, has long been suspected of causing adverse reproductive and developmental effects, but previous reviews were inconclusive, due in part, to limitations in the design of many of the human population studies. In the current review, we systematically evaluated evidence of an association between formaldehyde exposure and adverse reproductive and developmental effects, in human populations and in vivo animal studies, in the peer-reviewed literature. The mostly retrospective human studies provided evidence of an association of maternal exposure with adverse reproductive and developmental effects. Further assessment of this association by meta-analysis revealed an increased risk of spontaneous abortion (1.76, 95% CI 1.20–2.59, p=0.002) and of all adverse pregnancy outcomes combined (1.54, 95% CI 1.27–1.88, p<0.001), in formaldehyde-exposed women, although differential recall, selection bias, or confounding cannot be ruled out. Evaluation of the animal studies including all routes of exposure, doses and dosing regimens studied, suggested positive associations between formaldehyde exposure and reproductive toxicity, mostly in males. Potential mechanisms underlying formaldehyde-induced reproductive and developmental toxicities, including chromosome and DNA damage (genotoxicity), oxidative stress, altered level and/or function of enzymes, hormones and proteins, apoptosis, toxicogenomic and epigenomic effects (such as DNA methylation), were identified. To clarify these associations, well-designed molecular epidemiologic studies, that include quantitative exposure assessment and diminish confounding factors, should examine both reproductive and developmental outcomes associated with exposure in males and females. Together with mechanistic and animal studies, this will allow us to better understand the systemic effect of formaldehyde exposure. PMID:21787879

  6. Safety in the Chemical Laboratory: Atmospheric Formaldehyde Levels in an Academic Laboratory.

    ERIC Educational Resources Information Center

    Clausz, John C.; And Others

    1984-01-01

    Determined whether improved ventilation and use of "formaldehyde-free" biological specimens could reduce the levels of formaldehyde in air to which students and faculty would be exposed. Both methods were found to be effective in reducing formaldehyde levels in air. (JN)

  7. 21 CFR 177.1460 - Melamine-formaldehyde resins in molded articles.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Melamine-formaldehyde resins in molded articles... Repeated Use Food Contact Surfaces § 177.1460 Melamine-formaldehyde resins in molded articles. Melamine-formaldehyde resins may be safely used as the food-contact surface of molded articles intended for use...

  8. 40 CFR 721.9480 - Resorcinol, formaldehyde substituted carbomonocycle resin (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Resorcinol, formaldehyde substituted... New Uses for Specific Chemical Substances § 721.9480 Resorcinol, formaldehyde substituted... as resorcinol, formaldehyde substituted carbomonocycle resin (PMN P-89-769) is subject to...

  9. 40 CFR 721.7220 - Polymer of substituted phenol, formaldehyde, epichlorohydrin, and disubstituted benzene.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., formaldehyde, epichlorohydrin, and disubstituted benzene. 721.7220 Section 721.7220 Protection of Environment..., formaldehyde, epichlorohydrin, and disubstituted benzene. (a) Chemical substance and significant new uses..., formaldehyde, epichlorohydrin, and disubstituted benzene (PMN P-89-1104) is subject to reporting under...

  10. 40 CFR 721.7220 - Polymer of substituted phenol, formaldehyde, epichlorohydrin, and disubstituted benzene.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., formaldehyde, epichlorohydrin, and disubstituted benzene. 721.7220 Section 721.7220 Protection of Environment..., formaldehyde, epichlorohydrin, and disubstituted benzene. (a) Chemical substance and significant new uses..., formaldehyde, epichlorohydrin, and disubstituted benzene (PMN P-89-1104) is subject to reporting under...

  11. 40 CFR 721.7220 - Polymer of substituted phenol, formaldehyde, epichlorohydrin, and disubstituted benzene.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., formaldehyde, epichlorohydrin, and disubstituted benzene. 721.7220 Section 721.7220 Protection of Environment..., formaldehyde, epichlorohydrin, and disubstituted benzene. (a) Chemical substance and significant new uses..., formaldehyde, epichlorohydrin, and disubstituted benzene (PMN P-89-1104) is subject to reporting under...

  12. 40 CFR 721.3805 - Formaldehyde, reaction products with 1,3-benzenedimethanamine and bisphenol A.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.3805 Formaldehyde, reaction products... to reporting. (1) The chemical substance identified as formaldehyde, reaction products with 1,3... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Formaldehyde, reaction products with...

  13. 40 CFR 721.3805 - Formaldehyde, reaction products with 1,3-benzenedimethanamine and bisphenol A.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.3805 Formaldehyde, reaction products... to reporting. (1) The chemical substance identified as formaldehyde, reaction products with 1,3... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Formaldehyde, reaction products with...

  14. 40 CFR 721.3805 - Formaldehyde, reaction products with 1,3-benzenedimethanamine and bisphenol A.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.3805 Formaldehyde, reaction products... to reporting. (1) The chemical substance identified as formaldehyde, reaction products with 1,3... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, reaction products with...

  15. 40 CFR 721.3805 - Formaldehyde, reaction products with 1,3-benzenedimethanamine and bisphenol A.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.3805 Formaldehyde, reaction products... to reporting. (1) The chemical substance identified as formaldehyde, reaction products with 1,3... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Formaldehyde, reaction products with...

  16. 40 CFR 721.3805 - Formaldehyde, reaction products with 1,3-benzenedimethanamine and bisphenol A.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.3805 Formaldehyde, reaction products... to reporting. (1) The chemical substance identified as formaldehyde, reaction products with 1,3... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Formaldehyde, reaction products with...

  17. Formaldehyde: Industrial health hazards. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    Not Available

    1994-12-01

    The bibliography contains citations concerning the health hazards of formaldehyde inhalation. Health hazard evaluation reports of industrial sites are discussed, and the effects of formaldehyde on animals and humans are considered. Industrial hygiene sampling method and analytical methods to quantitate formaldehyde are also discussed. (Contains a minimum of 159 citations and includes a subject term index and title list.)

  18. Formaldehyde: Industrial health hazards. (Latest citations from the NTIS bibliographic database). Published Search

    SciTech Connect

    1996-03-01

    The bibliography contains citations concerning the health hazards of formaldehyde inhalation. Health hazard evaluation reports of industrial sites are discussed, and the effects of formaldehyde on animals and humans are considered. Industrial hygiene sampling method and analytical methods to quantitate formaldehyde are also discussed. (Contains 50-250 citations and includes a subject term index and title list.) (Copyright NERAC, Inc. 1995)

  19. 40 CFR 721.10533 - Amine-modified urea-formaldehyde polymer (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Amine-modified urea-formaldehyde... Specific Chemical Substances § 721.10533 Amine-modified urea-formaldehyde polymer (generic). (a) Chemical... as amine-modified urea-formaldehyde polymer (PMN P-12-182) is subject to reporting under this...

  20. 21 CFR 177.1900 - Urea-formaldehyde resins in molded articles.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Urea-formaldehyde resins in molded articles. 177... Repeated Use Food Contact Surfaces § 177.1900 Urea-formaldehyde resins in molded articles. Urea... section, urea-formaldehyde resins are those produced when 1 mole of urea is made to react with not...

  1. 21 CFR 177.1900 - Urea-formaldehyde resins in molded articles.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Urea-formaldehyde resins in molded articles. 177... for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1900 Urea-formaldehyde resins in molded articles. Urea-formaldehyde resins may be safely used as the food-contact...

  2. 21 CFR 177.1900 - Urea-formaldehyde resins in molded articles.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Urea-formaldehyde resins in molded articles. 177... for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1900 Urea-formaldehyde resins in molded articles. Urea-formaldehyde resins may be safely used as the food-contact...

  3. 40 CFR 721.10533 - Amine-modified urea-formaldehyde polymer (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Amine-modified urea-formaldehyde... Specific Chemical Substances § 721.10533 Amine-modified urea-formaldehyde polymer (generic). (a) Chemical... as amine-modified urea-formaldehyde polymer (PMN P-12-182) is subject to reporting under this...

  4. 21 CFR 177.1900 - Urea-formaldehyde resins in molded articles.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Urea-formaldehyde resins in molded articles. 177... for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1900 Urea-formaldehyde resins in molded articles. Urea-formaldehyde resins may be safely used as the food-contact...

  5. 21 CFR 177.1900 - Urea-formaldehyde resins in molded articles.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Urea-formaldehyde resins in molded articles. 177... for Use as Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1900 Urea-formaldehyde resins in molded articles. Urea-formaldehyde resins may be safely used as the food-contact...

  6. 40 CFR 721.7046 - Formaldehyde, polymer with substituted phenols, glycidyl ether.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, polymer with substituted... New Uses for Specific Chemical Substances § 721.7046 Formaldehyde, polymer with substituted phenols... substance identified as formaldehyde, polymer with substituted phenols, glycidyl ether (PMN P-93-955)...

  7. 40 CFR 721.3810 - Formaldehyde, polymers with substituted phenols (generic).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, polymers with... New Uses for Specific Chemical Substances § 721.3810 Formaldehyde, polymers with substituted phenols... identified generically as Formaldehyde, polymers with substituted phenols (PMN P-99-0558) is subject...

  8. 40 CFR 721.3807 - Formaldehyde, polymer with phenol and 1,2,3-propanetriol, methylated.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Formaldehyde, polymer with phenol and... Significant New Uses for Specific Chemical Substances § 721.3807 Formaldehyde, polymer with phenol and 1,2,3... chemical substance identified as formaldehyde, polymer with phenol and 1,2,3-propanetriol, methylated...

  9. 40 CFR 721.10232 - N-arylamino-phenol-formaldehyde condensate (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false N-arylamino-phenol-formaldehyde... Specific Chemical Substances § 721.10232 N-arylamino-phenol-formaldehyde condensate (generic). (a) Chemical... as n-arylamino-phenol-formaldehyde condensate (PMN P-08-694) is subject to reporting under...

  10. 40 CFR 721.3807 - Formaldehyde, polymer with phenol and 1,2,3-propanetriol, methylated.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Formaldehyde, polymer with phenol and... Significant New Uses for Specific Chemical Substances § 721.3807 Formaldehyde, polymer with phenol and 1,2,3... chemical substance identified as formaldehyde, polymer with phenol and 1,2,3-propanetriol, methylated...

  11. 40 CFR 721.3807 - Formaldehyde, polymer with phenol and 1,2,3-propanetriol, methylated.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Formaldehyde, polymer with phenol and... Significant New Uses for Specific Chemical Substances § 721.3807 Formaldehyde, polymer with phenol and 1,2,3... chemical substance identified as formaldehyde, polymer with phenol and 1,2,3-propanetriol, methylated...

  12. 40 CFR 721.10232 - N-arylamino-phenol-formaldehyde condensate (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false N-arylamino-phenol-formaldehyde... Specific Chemical Substances § 721.10232 N-arylamino-phenol-formaldehyde condensate (generic). (a) Chemical... as n-arylamino-phenol-formaldehyde condensate (PMN P-08-694) is subject to reporting under...

  13. 40 CFR 721.3812 - Substituted phenols and formaldehyde polymer, alkylated (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Substituted phenols and formaldehyde... New Uses for Specific Chemical Substances § 721.3812 Substituted phenols and formaldehyde polymer... substance identified generically as substituted phenols and formaldehyde polymer, alkylated (PMN...

  14. 40 CFR 721.10232 - N-arylamino-phenol-formaldehyde condensate (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false N-arylamino-phenol-formaldehyde... Specific Chemical Substances § 721.10232 N-arylamino-phenol-formaldehyde condensate (generic). (a) Chemical... as n-arylamino-phenol-formaldehyde condensate (PMN P-08-694) is subject to reporting under...

  15. 40 CFR 721.3807 - Formaldehyde, polymer with phenol and 1,2,3-propanetriol, methylated.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Formaldehyde, polymer with phenol and... Significant New Uses for Specific Chemical Substances § 721.3807 Formaldehyde, polymer with phenol and 1,2,3... chemical substance identified as formaldehyde, polymer with phenol and 1,2,3-propanetriol, methylated...

  16. 40 CFR 721.3812 - Substituted phenols and formaldehyde polymer, alkylated (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Substituted phenols and formaldehyde... New Uses for Specific Chemical Substances § 721.3812 Substituted phenols and formaldehyde polymer... substance identified generically as substituted phenols and formaldehyde polymer, alkylated (PMN...

  17. 40 CFR 721.3812 - Substituted phenols and formaldehyde polymer, alkylated (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Substituted phenols and formaldehyde... New Uses for Specific Chemical Substances § 721.3812 Substituted phenols and formaldehyde polymer... substance identified generically as substituted phenols and formaldehyde polymer, alkylated (PMN...

  18. 40 CFR 721.3807 - Formaldehyde, polymer with phenol and 1,2,3-propanetriol, methylated.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Formaldehyde, polymer with phenol and... Significant New Uses for Specific Chemical Substances § 721.3807 Formaldehyde, polymer with phenol and 1,2,3... chemical substance identified as formaldehyde, polymer with phenol and 1,2,3-propanetriol, methylated...

  19. 40 CFR 721.7046 - Formaldehyde, polymer with substituted phenols, glycidyl ether.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Formaldehyde, polymer with substituted... New Uses for Specific Chemical Substances § 721.7046 Formaldehyde, polymer with substituted phenols... substance identified as formaldehyde, polymer with substituted phenols, glycidyl ether (PMN P-93-955)...

  20. 40 CFR 721.3810 - Formaldehyde, polymers with substituted phenols (generic).

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Formaldehyde, polymers with... New Uses for Specific Chemical Substances § 721.3810 Formaldehyde, polymers with substituted phenols... identified generically as Formaldehyde, polymers with substituted phenols (PMN P-99-0558) is subject...

  1. Phosphorylation site on yeast pyruvate dehydrogenase complex

    SciTech Connect

    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 /sup 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.

  2. Synthesis and Thermal Degradation Studies of Melamine Formaldehyde Resins

    PubMed Central

    Ullah, Sami; Bustam, M. A.; Nadeem, M.; Tan, W. L.; Shariff, A. M.

    2014-01-01

    Melamine formaldehyde (MF) resins have been synthesized at different reaction temperature and pH values. Different molar ratios of melamine and formaldehyde were used to synthesize the corresponding resins. The prepared resin samples were characterized by using molecular weight determination viscometry and thermogravimetric analysis (TGA). The maximum percentage of solid content (69.7%) was obtained at pH 8.5 and 75°C temperature. The molecular weight of MF resin was increased with an increase of melamine monomer concentration. The highest residual weight 14.125 wt.% was obtained with sample 10. PMID:25436237

  3. Chemical and physical basics of routine formaldehyde fixation

    PubMed Central

    Thavarajah, Rooban; Mudimbaimannar, Vidya Kazhiyur; Elizabeth, Joshua; Rao, Umadevi Krishnamohan; Ranganathan, Kannan

    2012-01-01

    Formaldehyde is the widely employed fixative that has been studied for decades. The chemistry of fixation has been studied widely since the early 20th century. However, very few studies have been focused on the actual physics/chemistry aspect of process of this fixation. This article attempts to explain the chemistry of formaldehyde fixation and also to study the physical aspects involved in the fixation. The factors involved in the fixation process are discussed using well documented mathematical and physical formulae. The deeper understanding of these factors will enable pathologist to optimize the factors and use them in their favor. PMID:23248474

  4. Chemical and physical basics of routine formaldehyde fixation.

    PubMed

    Thavarajah, Rooban; Mudimbaimannar, Vidya Kazhiyur; Elizabeth, Joshua; Rao, Umadevi Krishnamohan; Ranganathan, Kannan

    2012-09-01

    Formaldehyde is the widely employed fixative that has been studied for decades. The chemistry of fixation has been studied widely since the early 20(th) century. However, very few studies have been focused on the actual physics/chemistry aspect of process of this fixation. This article attempts to explain the chemistry of formaldehyde fixation and also to study the physical aspects involved in the fixation. The factors involved in the fixation process are discussed using well documented mathematical and physical formulae. The deeper understanding of these factors will enable pathologist to optimize the factors and use them in their favor. PMID:23248474

  5. Some effects of formaldehyde on the upper respiratory tract

    SciTech Connect

    Ballenger, J.J.

    1984-11-01

    Being highly soluble in water gaseous formaldehyde (HCHO) is virtually completely removed by the nose during nasal respiration so that nasal disease may follow. This report is a review of pertinent information that is known about the effect of formaldehyde on the nose both in animals and humans. It is evident from the literature that rats develop nasal carcinoma at ambient levels of HCHO occasionally encountered by humans and it is hoped that this report will elucidate the possible threat HCHO presents to humans.

  6. Synthesis and thermal degradation studies of melamine formaldehyde resins.

    PubMed

    Ullah, Sami; Bustam, M A; Nadeem, M; Naz, M Y; Tan, W L; Shariff, A M

    2014-01-01

    Melamine formaldehyde (MF) resins have been synthesized at different reaction temperature and pH values. Different molar ratios of melamine and formaldehyde were used to synthesize the corresponding resins. The prepared resin samples were characterized by using molecular weight determination viscometry and thermogravimetric analysis (TGA). The maximum percentage of solid content (69.7%) was obtained at pH 8.5 and 75°C temperature. The molecular weight of MF resin was increased with an increase of melamine monomer concentration. The highest residual weight 14.125 wt.% was obtained with sample 10. PMID:25436237

  7. A survey of formaldehyde in high Galactic latitudes

    NASA Technical Reports Server (NTRS)

    Heithausen, A.; Mebold, U.; De Vries, H. W.

    1987-01-01

    The discovery of formaldehyde (H2CO) in four out of 15 CO-clouds observed in high Galactic latitudes is reported. For one of these a velocity-integrated formaldehyde map is presented. The clouds are clearly connected to CO clouds described by de Vries et al. (1986), to Lynds bright and dark nebulae (Lynds, 1963), and to the Galactic infrared cirrus (Low et al., 1984). The distribution of CO and H2CO clouds is compared. The depths of the l(10-11)H2CO lines show no correlation to the integrated J = l-0(C-12)O line intensities.

  8. Characterization of interactions of dihydrolipoamide dehydrogenase with its binding protein in the human pyruvate dehydrogenase complex

    SciTech Connect

    Park, Yun-Hee; Patel, Mulchand S.

    2010-05-07

    Unlike pyruvate dehydrogenase complexes (PDCs) from prokaryotes, PDCs from higher eukaryotes have an additional structural component, E3-binding protein (BP), for binding of dihydrolipoamide dehydrogenase (E3) in the complex. Based on the 3D structure of the subcomplex of human (h) E3 with the di-domain (L3S1) of hBP, the amino acid residues (H348, D413, Y438, and R447) of hE3 for binding to hBP were substituted singly by alanine or other residues. These substitutions did not have large effects on hE3 activity when measured in its free form. However, when these hE3 mutants were reconstituted in the complex, the PDC activity was significantly reduced to 9% for Y438A, 20% for Y438H, and 18% for D413A. The binding of hE3 mutants with L3S1 determined by isothermal titration calorimetry revealed that the binding affinities of the Y438A, Y438H, and D413A mutants to L3S1 were severely reduced (1019-, 607-, and 402-fold, respectively). Unlike wild-type hE3 the binding of the Y438A mutant to L3S1 was accompanied by an unfavorable enthalpy change and a large positive entropy change. These results indicate that hE3-Y438 and hE3-D413 play important roles in binding of hE3 to hBP.

  9. Experimental evidence that overexpression of NR2B glutamate receptor subunit is associated with brain vacuolation in adult glutaryl-CoA dehydrogenase deficient mice: A potential role for glutamatergic-induced excitotoxicity in GA I neuropathology.

    PubMed

    Rodrigues, Marília Danyelle Nunes; Seminotti, Bianca; Amaral, Alexandre Umpierrez; Leipnitz, Guilhian; Goodman, Stephen Irwin; Woontner, Michael; de Souza, Diogo Onofre Gomes; Wajner, Moacir

    2015-12-15

    Glutaric aciduria type I (GA I) is biochemically characterized by accumulation of glutaric and 3-hydroxyglutaric acids in body fluids and tissues, particularly in the brain. Affected patients show progressive cortical leukoencephalopathy and chronic degeneration of the basal ganglia whose pathogenesis is still unclear. In the present work we investigated parameters of bioenergetics and redox homeostasis in various cerebral structures (cerebral cortex, striatum and hippocampus) and heart of adult wild type (Gcdh(+/+)) and glutaryl-CoA dehydrogenase deficient knockout (Gcdh(-/-)) mice fed a baseline chow. Oxidative stress parameters were also measured after acute lysine overload. Finally, mRNA expression of NMDA subunits and GLT1 transporter was determined in cerebral cortex and striatum of these animals fed a baseline or high lysine (4.7%) chow. No significant alterations of bioenergetics or redox status were observed in these mice. In contrast, mRNA expression of the NR2B glutamate receptor subunit and of the GLT1 glutamate transporter was higher in cerebral cortex of Gcdh(-/-) mice. Furthermore, NR2B expression was markedly elevated in striatum of Gcdh(-/-) animals receiving chronic Lys overload. These data indicate higher susceptibility of Gcdh(-/-) mice to excitotoxic damage, implying that this pathomechanism may contribute to the cortical and striatum alterations observed in GA I patients. PMID:26671102

  10. Role of intragenic binding of cAMP responsive protein (CRP) in regulation of the succinate dehydrogenase genes Rv0249c-Rv0247c in TB complex mycobacteria

    PubMed Central

    Knapp, Gwendowlyn S.; Lyubetskaya, Anna; Peterson, Matthew W.; Gomes, Antonio L.C.; Ma, Zhuo; Galagan, James E.; McDonough, Kathleen A.

    2015-01-01

    Bacterial pathogens adapt to changing environments within their hosts, and the signaling molecule adenosine 3′, 5′-cyclic monophosphate (cAMP) facilitates this process. In this study, we characterized in vivo DNA binding and gene regulation by the cAMP-responsive protein CRP in M. bovis BCG as a model for tuberculosis (TB)-complex bacteria. Chromatin immunoprecipitation followed by deep-sequencing (ChIP-seq) showed that CRP associates with ∼900 DNA binding regions, most of which occur within genes. The most highly enriched binding region was upstream of a putative copper transporter gene (ctpB), and crp-deleted bacteria showed increased sensitivity to copper toxicity. Detailed mutational analysis of four CRP binding sites upstream of the virulence-associated Rv0249c-Rv0247c succinate dehydrogenase genes demonstrated that CRP directly regulates Rv0249c-Rv0247c expression from two promoters, one of which requires sequences intragenic to Rv0250c for maximum expression. The high percentage of intragenic CRP binding sites and our demonstration that these intragenic DNA sequences significantly contribute to biologically relevant gene expression greatly expand the genome space that must be considered for gene regulatory analyses in mycobacteria. These findings also have practical implications for an important bacterial pathogen in which identification of mutations that affect expression of drug target-related genes is widely used for rapid drug resistance screening. PMID:25940627

  11. Clinical relevance of short-chain acyl-CoA dehydrogenase (SCAD) deficiency: Exploring the role of new variants including the first SCAD-disease-causing allele carrying a synonymous mutation

    PubMed Central

    Tonin, Rodolfo; Caciotti, Anna; Funghini, Silvia; Pasquini, Elisabetta; Mooney, Sean D.; Cai, Binghuang; Proncopio, Elena; Donati, Maria Alice; Baronio, Federico; Bettocchi, Ilaria; Cassio, Alessandra; Biasucci, Giacomo; Bordugo, Andrea; la Marca, Giancarlo; Guerrini, Renzo; Morrone, Amelia

    2016-01-01

    Short-chain acyl-coA dehydrogenase deficiency (SCADD) is an autosomal recessive inborn error of mitochondrial fatty acid oxidation caused by ACADS gene alterations. SCADD is a heterogeneous condition, sometimes considered to be solely a biochemical condition given that it has been associated with variable clinical phenotypes ranging from no symptoms or signs to metabolic decompensation occurring early in life. A reason for this variability is due to SCAD alterations, such as the common p.Gly209Ser, that confer a disease susceptibility state but require a complex multifactorial/polygenic condition to manifest clinically. Our study focuses on 12 SCADD patients carrying 11 new ACADS variants, with the purpose of defining genotype–phenotype correlations based on clinical data, metabolite evaluation, molecular analyses, and in silico functional analyses. Interestingly, we identified a synonymous variant, c.765G > T (p.Gly255Gly) that influences ACADS mRNA splicing accuracy. mRNA characterisation demonstrated that this variant leads to an aberrant splicing product, harbouring a premature stop codon. Molecular analysis and in silico tools are able to characterise ACADS variants, identifying the severe mutations and consequently indicating which patients could benefit from a long term follow- up. We also emphasise that synonymous mutations can be relevant features and potentially associated with SCADD. PMID:27051597

  12. Clinical relevance of short-chain acyl-CoA dehydrogenase (SCAD) deficiency: Exploring the role of new variants including the first SCAD-disease-causing allele carrying a synonymous mutation.

    PubMed

    Tonin, Rodolfo; Caciotti, Anna; Funghini, Silvia; Pasquini, Elisabetta; Mooney, Sean D; Cai, Binghuang; Proncopio, Elena; Donati, Maria Alice; Baronio, Federico; Bettocchi, Ilaria; Cassio, Alessandra; Biasucci, Giacomo; Bordugo, Andrea; la Marca, Giancarlo; Guerrini, Renzo; Morrone, Amelia

    2016-06-01

    Short-chain acyl-coA dehydrogenase deficiency (SCADD) is an autosomal recessive inborn error of mitochondrial fatty acid oxidation caused by ACADS gene alterations. SCADD is a heterogeneous condition, sometimes considered to be solely a biochemical condition given that it has been associated with variable clinical phenotypes ranging from no symptoms or signs to metabolic decompensation occurring early in life. A reason for this variability is due to SCAD alterations, such as the common p.Gly209Ser, that confer a disease susceptibility state but require a complex multifactorial/polygenic condition to manifest clinically. Our study focuses on 12 SCADD patients carrying 11 new ACADS variants, with the purpose of defining genotype-phenotype correlations based on clinical data, metabolite evaluation, molecular analyses, and in silico functional analyses. Interestingly, we identified a synonymous variant, c.765G > T (p.Gly255Gly) that influences ACADS mRNA splicing accuracy. mRNA characterisation demonstrated that this variant leads to an aberrant splicing product, harbouring a premature stop codon. Molecular analysis and in silico tools are able to characterise ACADS variants, identifying the severe mutations and consequently indicating which patients could benefit from a long term follow- up. We also emphasise that synonymous mutations can be relevant features and potentially associated with SCADD. PMID:27051597

  13. In-situ Ground-Based and Airborne Formaldehyde Measurements in the Houston Area During TexAQS-II

    NASA Astrophysics Data System (ADS)

    Rappenglueck, B.; Byun, D.; Alvarez, S.; Buhr, M.; Coarfa, V.; Czader, B.; Dasgupta, P.; Estes, M.; Kim, S.; Leuchner, M.; Luke, W.; Shauck, M.; Zanin, G.

    2007-12-01

    Formaldehyde is considered to play a significant role in summertime photochemistry in the Houston area, in particular it is considered an important source for radicals. Secondary formation seems to be the most important fraction of ambient HCHO. Enhanced nighttime values may indicate primary sources. Potential sources may include mobile sources such as traffic exhaust, in particular not well maintained Diesel engines. Other possible sources may include point sources such as coffee roasting and flares from refineries. In this study we focused on the TexAQS-II continuous in-situ formaldehyde data set based on Hantzsch reaction which was obtained in the Ship Channel area (HRM3 and Lynchburg Ferry site) and at the Moody Tower for several weeks. We also include in-situ HCHO measurements obtained with the same technique aboard the Baylor aircraft during TexAQS-II flight missions. Formaldehyde data was compared to several trace gases that are supposed to be coemitted including CO (traffic), ethylene (flares), and SO2 (industry). In order to keep photochemical processes at a minimum special focus was on nighttime data. Case studies will be discussed where meteorological conditions including recirculation and boundary layer developments seem to play a major role in the redistribution of HCHO. Observations will be compared to CMAQ model studies.

  14. An autosomal glucose-6-phosphate dehydrogenase (hexose-6-phosphate dehydrogenase) polymorphism in human saliva.

    PubMed

    Tan, S G; Ashton, G C

    1976-01-01

    Glucose-6-phosphate dehydrogenase (hexose-6-phosphate dehydrogenase) from human saliva has been demonstrated by the zymogram technique. Three phenotypes were found. Family and population studies suggested that these phenotypes are the products of an autosomal locus with two alleles Sgd-1 and Sgd-2. PMID:950237

  15. Allergic contact dermatitis from formaldehyde textile resins in surgical uniforms and nonwoven textile masks.

    PubMed

    Donovan, Jeff; Skotnicki-Grant, Sandy

    2007-03-01

    Despite a trend for reduction in the concentration of free formaldehyde in textiles, formaldehyde textile resin (FTR) allergic contact dermatitis (ACD) remains an important clinical issue and is likely underdiagnosed. Patients with FTR ACD may react to formaldehyde released from the resin or to the resin itself. Screening with formaldehyde and ethyleneurea/melamine formaldehyde resin will uncover most cases. Patch testing with the suspected offending fabric most often leads to false-negative results. We present a case of a 49-year-old pediatrician who developed a severe widespread dermatitis caused by contact with FTRs from her hospital "greens" ("scrubs") and mask. PMID:17303043

  16. Acute airway effects of airborne formaldehyde in sensitized and non-sensitized mice housed in a dry or humid environment

    SciTech Connect

    Larsen, Søren Thor Wolkoff, Peder Hammer, Maria Kofoed-Sørensen, Vivi Clausen, Per Axel Nielsen, Gunnar Damgård

    2013-05-01

    We investigated the role of air humidity and allergic sensitization on the acute airway response to inhaled formaldehyde (FA) vapor. Mice were sensitized to the immunogen ovalbumin (OVA) by three intraperitoneal injections followed by two aerosol challenges, giving rise to allergic airway inflammation. Control mice were sham sensitized by saline injections and challenged by saline aerosols. Once sensitized, the mice were housed at high (85–89%) or low (< 10%) relative humidity, respectively for 48 h prior to a 60-min exposure to either 0.4, 1.8 or about 5 ppm FA. Before, during and after exposure, breathing parameters were monitored. These included the specific markers of nose and lung irritations as well as the expiratory flow rate, the latter being a marker of airflow limitation. The sensory irritation response in the upper airways was not affected by allergic inflammation or changes in humidity. At high relative humidity, the OVA-sensitized mice had a decreased expiratory airflow rate compared to the saline control mice after exposure to approximately 5 ppm FA. This is in accordance with the observations that asthmatics are more sensitive than non-asthmatics to higher concentrations of airway irritants including FA. In the dry environment, the opposite trend was seen; here, the saline control mice had a significantly decreased expiratory airflow rate compared to OVA-sensitized mice when exposed to 1.8 and 4 ppm FA. We speculate that increased mucus production in the OVA-sensitized mice has increased the “scrubber effect” in the nose, consequently protecting the conducting and lower airways. - Highlights: ► Role of air humidity and allergy on sensitivity to an airway irritant was studied. ► In the humid environment, allergy amplified the effects of formaldehyde. ► In the dry environment, allergy reduced the effect of formaldehyde. ► Neither allergy nor humidity changed the formaldehyde-induced nasal irritation.

  17. IRIS Toxicological Review of Formaldehyde (Interagency Science Consultation Draft)

    EPA Science Inventory

    On June 2, 2010, the Toxicological Review of Formaldehyde and the charge to external peer reviewers were released for external peer review and public comment. The Toxicological Review and charge were reviewed internally by EPA and by other federal agencies and White House Offices...

  18. An Alternative to Formaldehyde. Avoiding the Carcinogenic Risks.

    ERIC Educational Resources Information Center

    Ealy, Julie B.

    1991-01-01

    Demonstrations in which glyoxal may be substituted for formaldehyde, a known carcinogen, are presented. An acid-base clock reaction and a copper mirror on the inside of a test tube are described. Directions for the demonstrations and safety precautions are included. (KR)

  19. Concentrations of Glyoxal and Formaldehyde During CALNEX 2010

    NASA Astrophysics Data System (ADS)

    Henry, S. B.; Digangi, J. P.; Boyle, E.; Calnex Science Team

    2010-12-01

    Atmospheric oxidation of volatile organic compounds (VOCs) via the HOx-NOx cycle can lead to elevated concentrations of tropospheric ozone and secondary organic aerosol (SOA), both of which have been shown to be detrimental to human health. A detailed and mechanistic understanding of the VOC-HOx-NOx cycle is vital for improving the predictive capabilities of models for ozone and SOA. Accurate projection of oxidized VOCs is an important aspect of validating the photochemical mechanisms in models, which can then be used to evaluate regulation strategies. Glyoxal and formaldehyde are produced though oxidation of many important VOCs, and thus are powerful tracers of photooxidation via the HOx-NOx cycle. We report measurements of glyoxal and formaldehyde in Bakersfield, California located in the San Joaquin Valley during the CALNEX 2010 campaign (May 15th through June 30th). These measurements, with relevant trends and correlations, will be presented. Glyoxal:formaldehyde ratios will also be examined during this period. This ratio has been related to the source of VOCs dominating an air mass (i.e. anthropogenic versus biogenic). Both compounds were measured in situ with both high sensitivity and high temporal resolution (30 second) via laser induced emission techniques. Glyoxal was quantified by phosphorescence (MAD-LIP instrument) and formaldehyde by fluorescence (FILIF instrument). The measurements presented herein are useful for comparisons with current atmospheric models in order to evaluate the representation of photochemical oxidation in models. Furthermore, these data are also valuable points of comparison for satellite column retrieval data.

  20. BIOGENIC SOURCES FOR FORMALDEHYDE AND ACETALDEHYDE DURING SUMMER MONTHS

    EPA Science Inventory

    Photochemical modeling estimated contributions to ambient concentrations of formaldehyde and acetaldehyde from biogenic emissions over the continental United States during January 2001 (Eos Trans. AGU, 83(47), Fall Meet. Suppl., Abstract A52B-0117). Results showed that maximum co...

  1. The methods of formaldehyde emission testing of engine: A review

    NASA Astrophysics Data System (ADS)

    Zhang, Chunhui; Geng, Peng; Cao, Erming; Wei, Lijiang

    2015-12-01

    A number of measurements have been provided to detect formaldehyde in the atmosphere, but there are no clear unified standards in engine exhaust. Nowadays, formaldehyde, an unregulated emission from methanol engine, has been attracting increasing attention by researchers. This paper presents the detection techniques for formaldehyde emitted from the engines applied in recent market, introducing the approaches in terms of unregulated emission tests of formaldehyde, which involved gas chromatography, liquid chromatography, chromatography-mass spectrometry, chromatography-spectrum, Fourier infrared spectroscopy and spectrophotometry. The author also introduces the comparison regarding to the advantages of the existing detection techniques based on the principle, to compare with engine exhaust sampling method, the treatment in advance of detection, obtaining approaches accessing to the qualitative and quantitative analysis of chromatograms or spectra. The accuratest result obtained was chromatography though it cannot be used continuously. It also can be utilized to develop high requirements of emissions and other regulations. Fourier infrared spectroscopy has the advantage of continuous detection for a variety of unregulated emissions and can be applied to the bench in variable condition. However, its accuracy is not as good as chromatography. As the conclusion, a detection technique is chosen based on different requirements.

  2. Organocatalytic removal of formaldehyde adducts from RNA and DNA bases

    NASA Astrophysics Data System (ADS)

    Karmakar, Saswata; Harcourt, Emily M.; Hewings, David S.; Lovejoy, Alexander F.; Kurtz, David M.; Ehrenschwender, Thomas; Barandun, Luzi J.; Roost, Caroline; Alizadeh, Ash A.; Kool, Eric T.

    2015-09-01

    Formaldehyde is universally used to fix tissue specimens, where it forms hemiaminal and aminal adducts with biomolecules, hindering the ability to retrieve molecular information. Common methods for removing these adducts involve extended heating, which can cause extensive degradation of nucleic acids, particularly RNA. Here, we show that water-soluble bifunctional catalysts (anthranilates and phosphanilates) speed the reversal of formaldehyde adducts of mononucleotides over standard buffers. Studies with formaldehyde-treated RNA oligonucleotides show that the catalysts enhance adduct removal, restoring unmodified RNA at 37 °C even when extensively modified, while avoiding the high temperatures that promote RNA degradation. Experiments with formalin-fixed, paraffin-embedded cell samples show that the catalysis is compatible with common RNA extraction protocols, with detectable RNA yields increased by 1.5-2.4-fold using a catalyst under optimized conditions and by 7-25-fold compared with a commercial kit. Such catalytic strategies show promise for general use in reversing formaldehyde adducts in clinical specimens.

  3. Organocatalytic removal of formaldehyde adducts from RNA and DNA bases.

    PubMed

    Karmakar, Saswata; Harcourt, Emily M; Hewings, David S; Scherer, Florian; Lovejoy, Alexander F; Kurtz, David M; Ehrenschwender, Thomas; Barandun, Luzi J; Roost, Caroline; Alizadeh, Ash A; Kool, Eric T

    2015-09-01

    Formaldehyde is universally used to fix tissue specimens, where it forms hemiaminal and aminal adducts with biomolecules, hindering the ability to retrieve molecular information. Common methods for removing these adducts involve extended heating, which can cause extensive degradation of nucleic acids, particularly RNA. Here, we show that water-soluble bifunctional catalysts (anthranilates and phosphanilates) speed the reversal of formaldehyde adducts of mononucleotides over standard buffers. Studies with formaldehyde-treated RNA oligonucleotides show that the catalysts enhance adduct removal, restoring unmodified RNA at 37 °C even when extensively modified, while avoiding the high temperatures that promote RNA degradation. Experiments with formalin-fixed, paraffin-embedded cell samples show that the catalysis is compatible with common RNA extraction protocols, with detectable RNA yields increased by 1.5-2.4-fold using a catalyst under optimized conditions and by 7-25-fold compared with a commercial kit. Such catalytic strategies show promise for general use in reversing formaldehyde adducts in clinical specimens. PMID:26291948

  4. SORPTION AND REEMISSION OF FORMALDEHYDE BY GYPSUM WALLBOARD

    EPA Science Inventory

    The paper gives results of an analysis of the sorption and desorption of formaldehyde by unpainted wallboard, using a mass transfer model based on the Langmuir sorption isotherm. he sorption and desorption rate constants are determined by short-term experimental data. ong-term so...

  5. Resolving the Role of Plant NAD-Glutamate Dehydrogenase: III. Overexpressing Individually or Simultaneously the Two Enzyme Subunits Under Salt Stress Induces Changes in the Leaf Metabolic Profile and Increases Plant Biomass Production.

    PubMed

    Tercé-Laforgue, Thérèse; Clément, Gilles; Marchi, Laura; Restivo, Francesco M; Lea, Peter J; Hirel, Bertrand

    2015-10-01

    NAD-dependent glutamate dehydrogenase (NAD-GDH) of higher plants has a central position at the interface between carbon and nitrogen metabolism due to its ability to carry out the deamination of glutamate. In order to obtain a better understanding of the physiological function of NAD-GDH under salt stress conditions, transgenic tobacco (Nicotiana tabacum L.) plants that overexpress two genes from Nicotiana plumbaginifolia individually (GDHA and GDHB) or simultaneously (GDHA/B) were grown in the presence of 50 mM NaCl. In the different GDH overexpressors, the NaCl treatment induced an additional increase in GDH enzyme activity, indicating that a post-transcriptional mechanism regulates the final enzyme activity under salt stress conditions. A greater shoot and root biomass production was observed in the three types of GDH overexpressors following growth in 50 mM NaCl, when compared with the untransformed plants subjected to the same salinity stress. Changes in metabolites representative of the plant carbon and nitrogen status were also observed. They were mainly characterized by an increased amount of starch present in the leaves of the GDH overexpressors as compared with the wild type when plants were grown in 50 mM NaCl. Metabolomic analysis revealed that overexpressing the two genes GDHA and GDHB, individually or simultaneously, induced a differential accumulation of several carbon- and nitrogen-containing molecules involved in a variety of metabolic, developmental and stress-responsive processes. An accumulation of digalactosylglycerol, erythronate and porphyrin was found in the GDHA, GDHB and GDHA/B overexpressors, suggesting that these molecules could contribute to the improved performance of the transgenic plants under salinity stress conditions. PMID:26251210

  6. Essential role of aldehyde dehydrogenase 1A3 (ALDH1A3) for the maintenance of non-small cell lung cancer stem cells is associated with the STAT3 pathway

    PubMed Central

    Shao, Chunli; Sullivan, James P.; Girard, Luc; Augustyn, Alexander; Yenerall, Paul; Rodriguez, Jaime; Liu, Hui; Behrens, Carmen; Shay, Jerry W.; Wistuba, Ignacio I.; Minna, John D.

    2014-01-01

    Purpose Lung cancer stem cells (CSCs) with elevated aldehyde dehydrogenase (ALDH) activity are self-renewing, clonogenic and tumorigenic. The purpose of our study is to elucidate the mechanisms by which lung CSCs are regulated. Experimental Design A genome-wide gene expression analysis was performed to identify genes differentially expressed in the ALDH+ vs. ALDH− cells. RT-PCR, western blot and Aldefluor assay were used to validate identified genes. To explore the function in CSCs we manipulated their expression followed by colony and tumor formation assays. Results We identified a subset of genes that were differentially expressed in common in ALDH+ cells, among which ALDH1A3 was the most upregulated gene in ALDH+ vs. ALDH− cells. ShRNA-mediated knockdown of ALDH1A3 in NSCLCs resulted in a dramatic reduction in ALDH activity, clonogenicity and tumorigenicity, indicating that ALDH1A3 is required for tumorigenic properties. By contrast, overexpression of ALDH1A3 by itself it was not sufficient to increase tumorigenicity. The ALDH+ cells also expressed more activated Signal Transducers and Activators of Transcription 3 (STAT3) than ALDH− cells. Inhibition of STAT3 or its activator EZH2 genetically or pharmacologically diminished the level of ALDH+ cells and clonogenicity. Unexpectedly, ALDH1A3 was highly expressed in female, never smokers, well differentiated tumors, or adenocarcinoma. ALDH1A3 low expression was associated with poor overall survival. Conclusion Our data show that ALDH1A3 is the predominant ALDH isozyme responsible for ALDH activity and tumorigenicity in most NSCLCs, and that inhibiting either ALDH1A3 or the STAT3 pathway are potential therapeutic strategies to eliminate the ALDH+ subpopulation in NSCLCs. PMID:24907115

  7. The Role of Glutamate Dehydrogenase (GDH) Testing Assay in the Diagnosis of Clostridium difficile Infections: A High Sensitive Screening Test and an Essential Step in the Proposed Laboratory Diagnosis Workflow for Developing Countries like China.

    PubMed

    Cheng, Jing-Wei; Xiao, Meng; Kudinha, Timothy; Xu, Zhi-Peng; Sun, Lin-Ying; Hou, Xin; Zhang, Li; Fan, Xin; Kong, Fanrong; Xu, Ying-Chun

    2015-01-01

    The incidence and severity of Clostridium difficile infection (CDI) in North America and Europe has increased significantly since the 2000s. However, CDI is not widely recognized in China and other developing countries due to limited laboratory diagnostic capacity and low awareness. Most published studies on laboratory workflows for CDI diagnosis are from developed countries, and thus may not be suitable for most developing countries. Therefore, an alternative strategy for developing countries is needed. In this study, we evaluated the performance of the Glutamate Dehydrogenase (GDH) test and its associated workflow on 416 fecal specimens from suspected CDI cases. The assay exhibited excellent sensitivity (100.0%) and specificity (92.8%), compared to culture based method, and thus could be a good screening marker for C. difficile but not for indication of toxin production. The VIDAS CDAB assay, which can detect toxin A/B directly from fecal specimens, showed good specificity (99.7%) and positive predictive value (97.2%), but low sensitivity (45.0%) and negative predictive value (88.3%), compared with PCR-based toxin gene detection. Therefore, we propose a practical and efficient GDH test based workflow strategy for the laboratory diagnosis of CDI in developing countries like China. By applying this new workflow, the CDI laboratory diagnosis rate was notably improved in our center, yet the increasing cost was kept at a minimum level. Furthermore, to gain some insights into the genetic population structure of C. difficile isolates from our hospital, we performed MLST and PCR toxin gene typing. PMID:26659011

  8. The Role of Glutamate Dehydrogenase (GDH) Testing Assay in the Diagnosis of Clostridium difficile Infections: A High Sensitive Screening Test and an Essential Step in the Proposed Laboratory Diagnosis Workflow for Developing Countries like China

    PubMed Central

    Cheng, Jing-Wei; Xiao, Meng; Kudinha, Timothy; Xu, Zhi-Peng; Sun, Lin-Ying; Hou, Xin; Zhang, Li; Fan, Xin; Kong, Fanrong; Xu, Ying-Chun

    2015-01-01

    The incidence and severity of Clostridium difficile infection (CDI) in North America and Europe has increased significantly since the 2000s. However, CDI is not widely recognized in China and other developing countries due to limited laboratory diagnostic capacity and low awareness. Most published studies on laboratory workflows for CDI diagnosis are from developed countries, and thus may not be suitable for most developing countries. Therefore, an alternative strategy for developing countries is needed. In this study, we evaluated the performance of the Glutamate Dehydrogenase (GDH) test and its associated workflow on 416 fecal specimens from suspected CDI cases. The assay exhibited excellent sensitivity (100.0%) and specificity (92.8%), compared to culture based method, and thus could be a good screening marker for C. difficile but not for indication of toxin production. The VIDAS CDAB assay, which can detect toxin A/B directly from fecal specimens, showed good specificity (99.7%) and positive predictive value (97.2%), but low sensitivity (45.0%) and negative predictive value (88.3%), compared with PCR-based toxin gene detection. Therefore, we propose a practical and efficient GDH test based workflow strategy for the laboratory diagnosis of CDI in developing countries like China. By applying this new workflow, the CDI laboratory diagnosis rate was notably improved in our center, yet the increasing cost was kept at a minimum level. Furthermore, to gain some insights into the genetic population structure of C. difficile isolates from our hospital, we performed MLST and PCR toxin gene typing. PMID:26659011

  9. Formaldehyde treatment of proteins can constrain presentation to T cells by limiting antigen processing.

    PubMed Central

    di Tommaso, A; de Magistris, M T; Bugnoli, M; Marsili, I; Rappuoli, R; Abrignani, S

    1994-01-01

    Proteins to be used as vaccines are frequently treated with formaldehyde, although little is known about the effects of this treatment on protein antigenicity. To investigate the effect of formaldehyde treatment on antigen recognition by T cells, we compared the in vitro T-cell response to proteins that have been formaldehyde treated with the response to untreated proteins. We found that peripheral blood mononuclear cells from individuals vaccinated with three formaldehyde-treated proteins (pertussis toxin, filamentous hemagglutinin, pertactin) of Bordetella pertussis showed little or no response to the formaldehyde-treated proteins but proliferated very well in response to the corresponding untreated protein. These findings were further confirmed with CD4+ T-cell clones specific for defined epitopes of the bacterial proteins. We found that some epitopes are presented poorly or not at all when formaldehyde-treated proteins are used, whereas other epitopes are equally presented to T-cell clones when either formaldehyde-treated or untreated antigens are used. However, T-cell recognition could be restored by either antigen degradation before formaldehyde treatment or heat denaturation after such treatment. Parallel digestion with trypsin of both formaldehyde-treated and untreated proteins showed that fragments generated from the two forms of the same antigen were different in size. These results demonstrate that formaldehyde treatment can constrain antigen presentation to T cells and that this may be due to an altered proteolytic processing of formaldehyde-treated proteins. Images PMID:7513307

  10. A mathematical model for the absorption and metabolism of formaldehyde vapour by humans

    SciTech Connect

    Franks, S.J. . E-mail: Susan.Franks@hsl.gov.uk

    2005-08-15

    Epidemiological studies of occupational exposure to formaldehyde gas (HCHO) have suggested possible links between concentration and duration of exposure, and elevated risks of leukaemia and other cancers at sites distant from the site of contact. Formaldehyde is a highly water soluble gas which, when inhaled, reacts rapidly at the site of contact and is quickly metabolised by enzymes in the respiratory tissue. Inhaled formaldehyde is almost entirely absorbed in the respiratory tract and, for formaldehyde induced toxicity to occur at distant sites, HCHO must enter the blood and be transported to systemic tissues via the circulatory system. A mathematical model describing the absorption and removal of inhaled formaldehyde in the nasal tissue is therefore formulated to predict the proportion of formaldehyde entering into the blood. Accounting for the spatial distribution of the formaldehyde concentration and the metabolic activity within the mucosa, the concentration of formaldehyde in the mucus, the epithelium and the blood has been determined and was found to attain a steady-state profile within a few seconds of exposure. The increase of the formaldehyde concentration in the blood was predicted to be insignificant compared with the existing pre-exposure levels in the body, indicating that formaldehyde is rapidly removed in the nasal tissue. The results of the model thus suggest that it is highly unlikely that following inhalation by the nose, formaldehyde itself will cause toxicity at sites other than the initial site of contact in the respiratory tract.

  11. Adsorption and Reaction of Formaldehyde on Thin-film Cerium Oxide

    SciTech Connect

    Zhou,J.; Mullins, D.

    2006-01-01

    Formaldehyde adsorption and reaction have been studied on cerium oxide thin films that were vapor deposited on Ru(0 0 0 1). The formaldehyde behavior was examined as a function of temperature, exposure and Ce oxidation state. Formaldehyde chemisorbs on fully oxidized CeO{sub 2} as dioxymethylene, CH{sub 2}O{sub 2}. The dioxymethylene decomposes and desorbs as formaldehyde between 200 K and 400 K. No other products are formed. On reduced ceria, formaldehyde also adsorbs as dioxymethylene. In addition to the formaldehyde desorption between 200 K and 400 K, a more strongly bound form of dioxymethylene is formed that produces formaldehyde at 440 K. Above 400 K, some of the dioxymethylene reacts to form formate and methoxy on the surface. These species decompose to produce H{sub 2}, CO and CH{sub 2}O above 500 K.

  12. Benzene toxicity: emphasis on cytosolic dihydrodiol dehydrogenases

    SciTech Connect

    Bolcsak, L.E.

    1982-01-01

    Blood dyscrasias such as leukopenia and anemia have been clearly identified as consequences of chronic benzene exposure. The metabolites, phenol, catechol, and hydroquinone produced inhibition of /sup 59/Fe uptake in mice which followed the same time course as that produced by benzene. The inhibitor of benzene oxidation, 3-amino-1,2,4-triazole, mitigated the inhibitory effects of benzene and phenol only. These data support the contention that benzene toxicity is mediated by a metabolite and suggest that the toxicity of phenol is a consequence of its metabolism to hydroquinone and that the route of metabolism to catechol may also contribute to the production of toxic metabolite(s). The properties of mouse liver cytosolic dihydrodiol dehydrogenases were examined. These enzymes catalyze the NADP/sup +/-dependent oxidation of trans-1,2-dihydro-1,2-dihydroxybenzene (BDD) to catechol, a possible toxic metabolite of benzene produced via this metabolic route. Four distinct dihydrodiol dehydrogenases (DD1, DD2, DD3, and DD4) were purified to apparent homogeneity as judged by SDS polyacrylamide gel electrophoresis and isoelectric focusing. DD1 appeared to be identical to the major ketone reductase and 17..beta..-hydroxysteroid dehydrogenase activity in the liver. DD2 exhibited aldehyde reductase activity. DD3 and DD4 oxidized 17..beta..-hydroxysteroids, but no carbonyl reductase activity was detected. These relationships between BDD dehydrogenases and carbonyl reductase and/or 17..beta..-hydroxysteroid dehydrogenase activities were supported by several lines of evidence.

  13. Alteration of substrate specificity of alanine dehydrogenase

    PubMed Central

    Fernandes, Puja; Aldeborgh, Hannah; Carlucci, Lauren; Walsh, Lauren; Wasserman, Jordan; Zhou, Edward; Lefurgy, Scott T.; Mundorff, Emily C.

    2015-01-01

    The l-alanine dehydrogenase (AlaDH) has a natural history that suggests it would not be a promising candidate for expansion of substrate specificity by protein engineering: it is the only amino acid dehydrogenase in its fold family, it has no sequence or structural similarity to any known amino acid dehydrogenase, and it has a strong preference for l-alanine over all other substrates. By contrast, engineering of the amino acid dehydrogenase superfamily members has produced catalysts with expanded substrate specificity; yet, this enzyme family already contains members that accept a broad range of substrates. To test whether the natural history of an enzyme is a predictor of its innate evolvability, directed evolution was carried out on AlaDH. A single mutation identified through molecular modeling, F94S, introduced into the AlaDH from Mycobacterium tuberculosis (MtAlaDH) completely alters its substrate specificity pattern, enabling activity toward a range of larger amino acids. Saturation mutagenesis libraries in this mutant background additionally identified a double mutant (F94S/Y117L) showing improved activity toward hydrophobic amino acids. The catalytic efficiencies achieved in AlaDH are comparable with those that resulted from similar efforts in the amino acid dehydrogenase superfamily and demonstrate the evolvability of MtAlaDH specificity toward other amino acid substrates. PMID:25538307

  14. Anthracycline-Formaldehyde Conjugates and Their Targeted Prodrugs

    NASA Astrophysics Data System (ADS)

    Koch, Tad H.; Barthel, Benjamin L.; Kalet, Brian T.; Rudnicki, Daniel L.; Post, Glen C.; Burkhart, David J.

    The sequence of research leading to a proposal for anthracycline cross-linking of DNA is presented. The clinical anthracycline antitumor drugs are anthraquinones, and as such are redox active. Their redox chemistry leads to induction of oxidative stress and drug metabolites. An intermediate in reductive glycosidic cleavage is a quinone methide, once proposed as an alkylating agent of DNA. Subsequent research now implicates formaldehyde as a mediator of anthracycline-DNA cross-linking. The cross-link at 5'-GC-3' sites consists of a covalent linkage from the amino group of the anthracycline to the 2-amino group of the G-base through a methylene from formaldehyde, hydrogen bonding from the 9-OH to the G-base on the opposing strand, and hydrophobic interactions through intercalation of the anthraquinone. The combination of these interactions has been described as a virtual cross-link of DNA. The origin of the formaldehyde in vivo remains a mystery. In vitro, doxorubicin reacts with formaldehyde to give firstly a monomeric oxazolidine, doxazolidine, and secondly a dimeric oxazolidine, doxoform. Doxorubicin reacts with formaldehyde in the presence of salicylamide to give the N-Mannich base conjugate, doxsaliform. Doxsaliform is several fold more active in tumor cell growth inhibition than doxorubicin, but doxazolidine and doxoform are orders of magnitude more active than doxorubicin. Exploratory research on the potential for doxsaliform and doxazolidine as targeted cytotoxins is presented. A promising lead design is pentyl PABC-Doxaz, targeted to a carboxylesterase enzyme overexpressed in liver cancer cells and/or colon cancer cells.

  15. In vitro model for decontamination of human skin: formaldehyde.

    PubMed

    Zhai, H; Barbadillo, S; Hui, X; Maibach, H I

    2007-04-01

    Decontamination of a chemical from skin is often an emergency measure. This study utilized an in vitro model to compare the decontamination capacity of three model decontaminant solutions (tap water, isotonic saline, and hypertonic saline). Human cadaver skin was dosed (approximately 0.25 microg on 3 cm(2) per skin) with radio-labeled [(14)C]-formaldehyde. After a defined exposure time (1, 3, and 30 min post-dosing, respectively), the surface skin was washed three times (4ml per time) with each solution. After washing, the skin was stripped with tape discs twice. Lastly, the wash solutions, strippings, receptor fluid, and remainder of skin were liquid scintillation analyzer counted to determine the amounts of formaldehyde. Additionally, an evaporation test at different exposure times (1min, 3min, 15min, 30min, and 60min, respectively) was conducted to monitor formaldehyde % evaporation. There were no statistical differences among these groups except isotonic saline, at 3min post-exposure (in wash solutions), showed a significantly difference (p<0.05) when compared to tap water. Formaldehyde % evaporation increased linearly with extending application times, and were 7.7%, 13.6%, 19.7%, 24.4%, and 35.9% (1min, 3min, 15min, 30min, and 60min, respectively). This data suggests that isotonic saline may be effective in removing formaldehyde from skin. However, results from this model need validation in vivo. The model may provide a facile and robust method of accelerating knowledge of decontamination mechanism and lead to enhanced efficacy. PMID:17123683

  16. The Carbon Monoxide Dehydrogenase from Desulfovibrio vulgaris.

    PubMed

    Hadj-Saïd, Jessica; Pandelia, Maria-Eirini; Léger, Christophe; Fourmond, Vincent; Dementin, Sébastien

    2015-12-01

    Ni-containing Carbon Monoxide Dehydrogenases (CODHs) catalyze the reversible conversion between CO and CO₂and are involved in energy conservation and carbon fixation. These homodimeric enzymes house two NiFeS active sites (C-clusters) and three accessory [4Fe-4S] clusters. The Desulfovibrio vulgaris (Dv) genome contains a two-gene CODH operon coding for a CODH (cooS) and a maturation protein (cooC) involved in nickel insertion in the active site. According to the literature, the question of the precise function of CooC as a chaperone folding the C-cluster in a form which accommodates free nickel or as a mere nickel donor is not resolved. Here, we report the biochemical and spectroscopic characterization of two recombinant forms of the CODH, produced in the absence and in the presence of CooC, designated CooS and CooS(C), respectively. CooS contains no nickel and cannot be activated, supporting the idea that the role of CooC is to fold the C-cluster so that it can bind nickel. As expected, CooS(C) is Ni-loaded, reversibly converts CO and CO₂, displays the typical Cred1 and Cred2 EPR signatures of the C-cluster and activates in the presence of methyl viologen and CO in an autocatalytic process. However, Ni-loaded CooS(C) reaches maximum activity only upon reductive treatment in the presence of exogenous nickel, a phenomenon that had not been observed before. Surprisingly, the enzyme displays the Cred1 and Cred2 signatures whether it has been activated or not, showing that this activation process of the Ni-loaded Dv CODH is not associated with structural changes at the active site. PMID:26255854

  17. Two different dihydroorotate dehydrogenases in Lactococcus lactis.

    PubMed Central

    Andersen, P S; Jansen, P J; Hammer, K

    1994-01-01

    The pyrimidine de novo biosynthesis pathway has been characterized for a number of organisms. The general pathway consists of six enzymatic steps. In the characterization of the pyrimidine pathway of Lactococcus lactis, two different pyrD genes encoding dihydroorotate dehydrogenase were isolated. The nucleotide sequences of the two genes, pyrDa and pyrDb, have been determined. One of the deduced amino acid sequences has a high degree of homology to the Saccharomyces cerevisiae dihydroorotate dehydrogenase, and the other resembles the dihydroorotate dehydrogenase from Bacillus subtilis. It is possible to distinguish between the two enzymes in crude extracts by using different electron acceptors. We constructed mutants containing a mutated form of either one or the other or both of the pyrD genes. Only the double mutant is pyrimidine auxotrophic. Images PMID:8021180

  18. 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

    PubMed Central

    Bechor, Edna; Dahan, Iris; Fradin, Tanya; Berdichevsky, Yevgeny; Zahavi, Anat; Federman Gross, Aya; Rafalowski, Meirav; Pick, Edgar

    2015-01-01

    The superoxide (O·−2)-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 O·−2 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

  19. 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 p67 (phox.).

    PubMed

    Bechor, Edna; Dahan, Iris; Fradin, Tanya; Berdichevsky, Yevgeny; Zahavi, Anat; Federman Gross, Aya; Rafalowski, Meirav; Pick, Edgar

    2015-01-01

    The superoxide (O(·-) 2)-generating NADPH oxidase of phagocytes consists of a membrane component, cytochrome b 558 (a heterodimer of Nox2 and p22 (phox) ), and four cytosolic components, p47 (phox) , p67 (phox) , p40 (phox) , and Rac. The catalytic component, responsible for O(·-) 2 generation, is Nox2. It is activated by the interaction of the dehydrogenase region (DHR) of Nox2 with the cytosolic components, principally with p67 (phox) . Using a peptide-protein binding assay, we found that Nox2 peptides containing a (369)CysGlyCys(371) triad (CGC) bound p67 (phox) with high affinity, dependent upon the establishment of a disulfide bond between the two cysteines. Serially truncated recombinant Nox2 DHR proteins bound p67 (phox) 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 p67 (phox) 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) p67 (phox) , 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 p67 (phox) to Nox2 via disulfide bonds, by virtue of the intrinsic PDI activity of Nox2, stabilizes

  20. Orchestration of Enzymatic Processing by Thiazole/Oxazole-Modified Microcin Dehydrogenases

    PubMed Central

    Melby, Joel O.; Li, Xiangpo; Mitchell, Douglas A.

    2014-01-01

    Thiazole/oxazole-modified microcins (TOMMs) comprise a structurally diverse family of natural products with varied bioactivities linked by the presence of posttranslationally installed thiazol(in)e and oxazol(in)e heterocycles. The detailed investigation of the TOMM biosynthetic enzymes from Bacillus sp. Al Hakam (Balh) has provided significant insight into heterocycle biosynthesis. Thiazoles and oxazoles are installed by the successive action of an ATP-dependent cyclodehydratase (C- and D-protein) and a FMN-dependent dehydrogenase (B-protein), which are responsible for azoline formation and azoline oxidation, respectively. Although several studies have focused on the mechanism of azoline formation, many details regarding the role of the dehydrogenase (B-protein) in overall substrate processing remain unknown. In this work, we evaluated the involvement of the dehydrogenase in determining the order of ring formation, as well as the promiscuity of the Balh and microcin B17 cyclodehydratases to accept a panel of noncognate dehydrogenases. In support of the observed promiscuity, a fluorescence polarization assay was utilized to measure binding of the dehydrogenase to the cyclodehydratase using the intrinsic fluorescence of the FMN cofactor. Ultimately, the noncognate dehydrogenases were shown to possess cyclodehydratase-independent activity. A previous study identified a conserved Lys-Tyr motif to be important for dehydrogenase activity. Using the tools developed in this study, the Lys-Tyr motif was shown to not alter complex formation with the cyclodehydratase nor the reduction potential. Taken with the known crystal structure of a homolog, our data suggest that the Lys-Tyr motif is of catalytic importance. Overall, this study provides a greater level of insight into the complex orchestration of enzymatic activity during TOMM biosynthesis. PMID:24364559

  1. Formaldehyde as a trigger for protein aggregation and potential target for mitigation of age-related, progressive cognitive impairment.

    PubMed

    Su, Tao; Monte, Woodrow C; Hu, Xintian; He, Yingge; He, Rongqiao

    2016-01-01

    Recently, formaldehyde (FA), existing in a number of different cells including neural cells, was found to affect age-related cognitive impairment. Oral administration of methanol (the metabolic precursor of FA) triggers formation of senile plaques (SPs) and Tau hyperphosphorylation in the brains of monkeys with memory decline. Intraperitoneal injection of FA leads to hyperphosphorylation of Tau in wild-type mouse brains and N2a cells through activation of glycogen synthase kinase-3β (GSK-3β). Furthermore, formaldehyde at low concentrations can directly induce Tau aggregation and amyloid β (Aβ) peptide deposits in vitro. Formaldehyde-induced Tau aggregation is implicated in cytotoxicity and neural cell apoptosis. Clarifying how FA triggers Aβ deposits and Tau hyperphosphorlyation will not only improve our understanding of the molecular and cellular mechanisms of age-related cognitive impairment but will also contribute to the ongoing investigation of alternate targets for new drugs. Here, we review the role of FA, particularly that of endogenous origin, in protein aggregation and as a potential drug intervention in the development of agerelated cognitive impairment. PMID:26268337

  2. Assessment of freshness and freeze-thawing of sea bream fillets (Sparus aurata) by a cytosolic enzyme: Lactate dehydrogenase.

    PubMed

    Diop, Mamadou; Watier, Denis; Masson, Pierre-Yves; Diouf, Amadou; Amara, Rachid; Grard, Thierry; Lencel, Philippe

    2016-11-01

    The evaluation of freshness and freeze-thawing of fish fillets was carried out by assessment of autolysis of cells using a cytosolic enzyme lactate dehydrogenase. Autolysis plays an important role in spoilage of fish and postmortem changes in fish tissue are due to the breakdown of the cellular structures and release of cytoplasmic contents. The outflow of a cytosolic enzyme, lactate dehydrogenase, was studied in sea bream fillets and the Sparus aurata fibroblasts (SAF-1) cell-line during an 8day storage period at +4°C. A significant increase of lactate dehydrogenase release was observed, especially after 5days of storage. The ratio between the free and the total lactate dehydrogenase activity is a promising predictive marker to measure the quality of fresh fish fillets. The effect of freeze-thawing on cytosolic lactate dehydrogenase and lysosomal α-d-glucosidase activities was also tested. Despite the protecting effect of the tissue compared to the cell-line, a loss of lactate dehydrogenase activity, but not of α-d-glucosidase, was observed. In conclusion, lactate dehydrogenase may be used as a marker to both assess freshness of fish and distinguish between fresh and frozen-thawed fish fillets. PMID:27211667

  3. Multiple transcripts encode glucose 6-phosphate dehydrogenase in the southern cattle tick, Rhipicephalus (Boophilus) microplus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Glucose 6-phosphate dehydrogenase (G6PDH) is an enzyme that plays a critical role in the production of NADPH. Here we describe the identification of four transcripts (G6PDH-A, -B, -C, and -D) that putatively encode the enzyme in the southern cattle tick, Rhipicephalus (Boophilus) microplus. The geno...

  4. Effects of a 3β-hydroxysteroid Dehydrogenase Inhibitor, Trilostane, on the Fathead Minnow Reproductive Axis

    EPA Science Inventory

    A number of environmental contaminants and plant flavonoid compounds have been shown to inhibit the activity of 3β-hydroxysteroid dehydrogenase/Δ5-Δ4 isomerase (3β-HSD). Because 3β-HSD plays a critical role in steroid hormone synthesis, inhibition of 3β-HSD represents a potentia...

  5. Isotope effects and their implications for the covalent binding of inhaled (/sup 3/H)- and (/sup 14/C)formaldehyde in the rat nasal mucosa

    SciTech Connect

    Heck Hd'; Casanova, M.

    1987-06-15

    DNA-protein crosslinks were formed in the nasal respiratory mucosa of Fischer-344 rats exposed for 3 hr to selected concentrations of (/sup 3/H)- and (/sup 14/C)formaldehyde (/sup 3/HCHO and H/sup 14/CHO). In rats depleted of glutathione (GSH) and exposed to 10 ppm of /sup 3/HCHO and H/sup 14/CHO, the /sup 3/H//sup 14/C ratio of the fraction of the DNA that was crosslinked to proteins was significantly (39 +/- 6%) higher than that of the inhaled gas. This suggests an isotope effect, either on the formation of DNA-protein crosslinks by labeled HCHO or on the oxidation of labeled HCHO catalyzed by formaldehyde (FDH) or aldehyde dehydrogenase (AldDH). The possibility of an isotope effect on the formation of crosslinks was investigated using rat hepatic nuclei incubated with (/sup 3/H)- and (/sup 14/C)formaldehyde (0.1 mM, 37 degrees C). A small (3.4 +/- 0.9%) isotope effect was detected on this reaction, which slightly favored /sup 3/HCHO over H/sup 14/CHO in binding to DNA. The magnitude of this isotope effect cannot account for the high isotope ratio observed in the crosslinked DNA in vivo. The possibility of an isotope effect on the oxidation of /sup 3/HCHO and H/sup 14/CHO catalyzed by FDH was investigated using homogenates of the rat nasal mucosa incubated with (/sup 3/H)- and (/sup 14/C)formaldehyde at total formaldehyde concentrations ranging from 0.1 to 11 microM, NAD+ (1 mM), GSH (15 mM), and pyrazole (1 mM). The experiments showed that /sup 3/HCHO is oxidized significantly more slowly than H/sup 14/CHO under these conditions (Vmax/Km (H/sup 14/CHO) divided by Vmax/Km (/sup 3/HCHO) = 1.82 +/- 0.11). A similar isotope effect was observed in the absence of GSH, presumably due to the oxidation of /sup 3/HCHO and H/sup 14/CHO catalyzed by AldDH.

  6. Isolated tumoral pyruvate dehydrogenase can synthesize acetoin which inhibits pyruvate oxidation as well as other aldehydes.

    PubMed

    Baggetto, L G; Lehninger, A L

    1987-05-29

    Oxidation of 1 mM pyruvate by Ehrlich and AS30-D tumor mitochondria is inhibited by acetoin, an unusual and important metabolite of pyruvate utilization by cancer cells, by acetaldehyde, methylglyoxal and excess pyruvate. The respiratory inhibition is reversed by other substrates added to pyruvate and also by 0.5 mM ATP. Kinetic properties of pyruvate dehydrogenase complex isolated from these tumor mitochondria have been studied. This complex appears to be able to synthesize acetoin from acetaldehyde plus pyruvate and is competitively inhibited by acetoin. The role of a new regulatory pattern for tumoral pyruvate dehydrogenase is presented. PMID:3593337

  7. Phenol-formaldehyde resin substitutes from biomass tars

    SciTech Connect

    Himmelblau, D.A.

    1995-11-01

    Approximately 320,000 tonnes of phenol and formaldehyde are currently used annually in North America to make adhesive resins that are used to make exterior-grade structural panels. The demand for phenol-formaldehyde (PF) resins is growing faster than the demand for panels, because more adhesive is required to join/coat the surface of wood flakes (for oriented strand board - OSB) than is required to join veneer; OSB is replacing plywood as logs large enough for veneer become scarcer. Also, competitive uses for phenol and methanol (for making formaldehyde) have increased raw materials cost and threatened availability. Production of adhesive resins from biomass to reduce reliance on raw materials derived from commodity petrochemicals and to lower resin cost looks attractive. A simple fluidized-bed reactor system can be used to produce tars that can substitute for a major portion of the phenol and formaldehyde in PF resin adhesives. This can be done in an air-fluidized, single-bed reactor; no inert gas or dual-bed system is required. The key is recognizing that optimum phenolic character in the tar is not produced at the maximum tar yield, but at reactor temperatures around 600{degrees}C and short gas-phase residence times that produce a yield of about 25 to 30 weight percent. A wide range of phenols, aldehydes and other compounds capable of polymerization are produced. Feedstock can be any wood waste larger than sander dust; low cost agricultural wastes such as bagasse are also suitable. Adhesive resin is produced from the entire tar product by shifting the pH from acidic to basic with NaOH, and combining and heating the resulting resole with phenol and formaldehyde, similarly to conventional resins. Approximately half of the phenol and formaldehyde by weight can be replaced with tar. A plant producing 13,865,000 kg (30,566,000 lb) annually from 308 tonnes (340 tons) per day of green wood chips would cost approximately $8,400,000.

  8. Simultaneous functions of the installed DAS/DAK formaldehyde-assimilation pathway and the original formaldehyde metabolic pathways enhance the ability of transgenic geranium to purify gaseous formaldehyde polluted environment.

    PubMed

    Zhou, Shengen; Xiao, Sunqin; Xuan, Xiuxia; Sun, Zhen; Li, Kunzhi; Chen, Limei

    2015-04-01

    The overexpression of dihydroxyacetone synthase (DAS) and dihydroxyacetone kinase (DAK) from methylotrophic yeasts in chloroplasts created a photosynthetic formaldehyde (HCHO)-assimilation pathway (DAS/DAK pathway) in transgenic tobacco. Geranium has abilities to absorb and metabolize HCHO. Results of this study showed that the installed DAS/DAK pathway functioning in chloroplasts greatly enhanced the role of the Calvin cycle in transgenic geranium under high concentrations of gaseous HCHO stress. Consequently, the yield of sugars from HCHO-assimilation increased approximately 6-fold in transgenic geranium leaves, and concomitantly, the role of three original HCHO metabolic pathways reduced, leading to a significant decrease in formic acid, citrate and glycine production from HCHO metabolism. Although the role of three metabolic pathways reduced in transgenic plants under high concentrations of gaseous HCHO stress, the installed DAS/DAK pathway could still function together with the original HCHO metabolic pathways. Consequently, the gaseous HCHO-resistance of transgenic plants was significantly improved, and the generation of H2O2 in the transgenic geranium leaves was significantly less than that in the wild type (WT) leaves. Under environmental-polluted gaseous HCHO stress for a long duration, the stomata conductance of transgenic plants remained approximately 2-fold higher than that of the WT, thereby increasing its ability to purify gaseous HCHO polluted environment. PMID:25698666

  9. Hydraulic Permeability of Resorcinol-Formaldehyde Resin

    SciTech Connect

    Taylor, Paul Allen

    2010-01-01

    An ion exchange process using spherical resorcinol-formaldehyde (RF) resin is the baseline process for removing cesium from the dissolved salt solution in the high-level waste tanks at the Hanford Site, using large scale columns as part of the Waste Treatment Plant (WTP). The RF resin is also being evaluated for use in the proposed small column ion exchange (SCIX) system, which is an alternative treatment option at Hanford and at the Savannah River Site (SRS). A recirculating test loop with a small ion exchange column was used to measure the effect of oxygen uptake and radiation exposure on the permeability of a packed bed of the RF resin. The lab-scale column was designed to be prototypic of the proposed Hanford columns at the WTP. Although the test equipment was designed to model the Hanford ion exchange columns, the data on changes in the hydraulic permeability of the resin will also be valuable for determining potential pressure drops through the proposed SCIX system. The superficial fluid velocity in the lab-scale test (3.4-5.7 cm/s) was much higher than is planned for the full-scale Hanford columns to generate the maximum pressure drop expected in those columns (9.7 psig). The frictional drag from this high velocity produced forces on the resin in the lab-scale tests that matched the design basis of the full-scale Hanford column. Any changes in the resin caused by the radiation exposure and oxygen uptake were monitored by measuring the pressure drop through the lab-scale column and the physical properties of the resin. Three hydraulic test runs were completed, the first using fresh RF resin at 25 C, the second using irradiated resin at 25 C, and the third using irradiated resin at 45 C. A Hanford AP-101 simulant solution was recirculated through a test column containing 500 mL of Na-form RF resin. Known amounts of oxygen were introduced into the primary recirculation loop by saturating measured volumes of the simulant solution with oxygen and reintroducing

  10. Alcohol dehydrogenases from Scheffersomyces stipitis involved in the detoxification of aldehyde inhibitors derived from lignocellulosic biomass conversion.

    PubMed

    Ma, Menggen; Wang, Xu; Zhang, Xiaoping; Zhao, Xianxian

    2013-09-01

    Aldehyde inhibitors such as furfural and 5-hydroxymethylfurfural (HMF) are generated from biomass pretreatment. Scheffersomyces stipitis is able to reduce furfural and HMF to less toxic furanmethanol and furan-2,5-dimethanol; however, the enzymes involved in the reductive reaction still remain unknown. In this study, transcription responses of two known and five putative alcohol dehydrogenase genes from S. stipitis were analyzed under furfural and HMF stress conditions. All the seven alcohol dehydrogenase genes were also cloned and overexpressed for their activity analyses. Our results indicate that transcriptions of SsADH4 and SsADH6 were highly induced under furfural and HMF stress conditions, and the proteins encoded by them exhibited NADH- and/or NADPH-dependent activities for furfural and HMF reduction, respectively. For furfural reduction, NADH-dependent activity was also observed in SsAdh1p and NAD(P)H-dependent activities were also observed in SsAdh5p and SsAdh7p. For HMF reduction, NADPH-dependent activities were also observed in SsAdh5p and SsAdh7p. SsAdh4p displayed the highest NADPH-dependent specific activity and catalytic efficiency for reduction of both furfural and HMF among the seven alcohol dehydrogenases. Enzyme activities of all SsADH proteins were more stable under acidic condition. For most SsADH proteins, the optimum temperature for enzyme activities was 30 °C and more than 50 % enzyme activities remained at 60 °C. Reduction activities of formaldehyde, acetaldehyde, isovaleraldehyde, benzaldehyde, and phenylacetaldehyde were also observed in some SsADH proteins. Our results indicate that multiple alcohol dehydrogenases in S. stipitis are involved in the detoxification of aldehyde inhibitors derived from lignocellulosic biomass conversion. PMID:23912116

  11. Formaldehyde-releasers in cosmetics: relationship to formaldehyde contact allergy. Part 1. Characterization, frequency and relevance of sensitization, and frequency of use in cosmetics.

    PubMed

    de Groot, Anton C; White, Ian R; Flyvholm, Mari-Ann; Lensen, Gerda; Coenraads, Pieter-Jan

    2010-01-01

    In this part of a series of review articles on formaldehyde-releasers and their relationship to formaldehyde contact allergy, formaldehyde-releasers in cosmetics are discussed. In this first part of the article, key data are presented including frequency of sensitization and of their use in cosmetics. In Europe, low frequencies of sensitization have been observed to all releasers: 2-bromo-2-nitropropane-1,3-diol 0.4-1.2%, diazolidinyl urea 0.5-1.4%, imidazolidinyl urea 0.3-1.4%, quaternium-15 0.6-1.9% (for DMDM hydantoin no recent data are available). All releasers score (far) higher prevalences in the USA; the possible explanations for this are discussed. The relevance of positive patch test reactions has been insufficiently investigated. In the USA, approximately 20% of cosmetics and personal care products (stay-on products: 17%, rinse-off products 27%) contain a formaldehyde-releaser. The use of quaternium-15 is decreasing. For Europe, there are no comparable recent data available. In the second part of the article, the patch test relationship of the releasers in cosmetics to formaldehyde contact allergy will be reviewed and it will be assessed whether products preserved with formaldehyde-releasers may contain enough free formaldehyde to pose a threat to individuals who have contact allergy to formaldehyde. PMID:20136875

  12. 40 CFR Appendix A to Subpart Hhhh... - Method for Determining Free-Formaldehyde in Urea-Formaldehyde Resins by Sodium Sulfite (Iced...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 12 2010-07-01 2010-07-01 true Method for Determining Free-Formaldehyde in Urea-Formaldehyde Resins by Sodium Sulfite (Iced & Cooled) A Appendix A to Subpart HHHH of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS...

  13. 40 CFR Appendix A to Subpart Hhhh... - Method for Determining Free-Formaldehyde in Urea-Formaldehyde Resins by Sodium Sulfite (Iced...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... samples that decompose to yield formaldehyde under the conditions of other free-formaldehyde methods. The... g methanol). 2.2.5Sodium chloride (NaCl) (reagent grade). 2.2.6Sodium hydroxide (NaOH). 2.3Procedure... American Chemical Society analytical reagent grade or better. 3.2.1One 1-liter (L) volumetric flask...

  14. 40 CFR Appendix A to Subpart Hhhh... - Method for Determining Free-Formaldehyde in Urea-Formaldehyde Resins by Sodium Sulfite (Iced...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 13 2013-07-01 2012-07-01 true Method for Determining Free-Formaldehyde in Urea-Formaldehyde Resins by Sodium Sulfite (Iced & Cooled) A Appendix A to Subpart HHHH of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS...

  15. 40 CFR Appendix A to Subpart Hhhh... - Method for Determining Free-Formaldehyde in Urea-Formaldehyde Resins by Sodium Sulfite (Iced...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 13 2012-07-01 2012-07-01 false Method for Determining Free-Formaldehyde in Urea-Formaldehyde Resins by Sodium Sulfite (Iced & Cooled) A Appendix A to Subpart HHHH of Part 63 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS...

  16. Biochemical Characterization of Putative Adenylate Dimethylallyltransferase and Cytokinin Dehydrogenase from Nostoc sp. PCC 7120.

    PubMed

    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. PMID:26376297

  17. Biochemical Characterization of Putative Adenylate Dimethylallyltransferase and Cytokinin Dehydrogenase from Nostoc sp. PCC 7120

    PubMed Central

    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. PMID:26376297

  18. Psoriatic therapeutics and glucose-6-phosphate dehydrogenase.

    PubMed

    Cotton, D W; van Rossum, E

    1975-01-01

    The inhibitory effects of various agents on the enzyme glucose-6-phosphate dehydrogenase have been studied in vitro. Stress is laid on the calculation of kinetic parameters such as true K-I values. The most active inhibitor was methotrexate, closely followed by cGMP. The increase in inhibitory activity after incubation of methotrexate with liver slices is discussed. PMID:167665

  19. Multiple retinoid dehydrogenases in testes cytosol from alcohol dehydrogenase negative or positive deermice.

    PubMed

    Posch, K C; Napoli, J L

    1992-05-28

    Retinoic acid syntheses from retinol by cytosol from testes of alcohol dehydrogenase negative or positive deermice were similar in specific activity and in their insensitivity to 1 M ethanol or 100 mM 4-methylpyrazole. Anion-exchange followed by size-exclusion chromatography revealed multiple and similarly migrating peaks in each cytosol that had both retinol and retinal dehydrogenase activities. Thus, the effects of ethanol on testes cannot be caused by direct inhibition of cytosolic retinoic acid synthesis because retinoid dehydrogenases distinct from mouse class A2 alcohol dehydrogenases, which corresponds to human class I, occurred in testes and they were not inhibited by ethanol. These data also demonstrate the occurrence of multiple cytosolic retinoic acid synthesis activities and indicate that the two reactions of cytosolic retinoic acid synthesis, retinol and retinal dehydrogenation, may be catalyzed by enzymes that occur as complexes. PMID:1599517

  20. Electrospun nanofibrous chitosan membranes modified with polyethyleneimine for formaldehyde detection.

    PubMed

    Wang, Na; Wang, Xianfeng; Jia, Yongtang; Li, Xiaoqi; Yu, Jianyong; Ding, Bin

    2014-08-01

    Here we describe a formaldehyde sensor fabricated by coating polyethyleneimine (PEI) functionalized chitosan nanofiber-net-binary structured layer on quartz crystal microbalance (QCM). The chitosan fibrous substrate comprising nanofibers and spider-web-like nano-nets constructed by a facile electro-spinning/netting process provided an ideal structure for the uniform PEI modification and sensing performance enhancement. Benefiting from the fascinating nanostructure, abundant primary amine groups of PEI, and strong adhesive force to the QCM electrode of PEI-chitosan membranes, the developed formaldehyde sensor presented rapid response and low detection limit (5 ppm) at room temperature. These findings have important implications in fabricating multi-dimensional nanostructures on QCM for gas sensing and chemical analysis. PMID:24751264

  1. Simple, rapid method for the preparation of isotopically labeled formaldehyde

    DOEpatents

    Hooker, Jacob Matthew; Schonberger, Matthias; Schieferstein, Hanno; Fowler, Joanna S.

    2011-10-04

    Isotopically labeled formaldehyde (*C.sup..sctn.H.sub.2O) is prepared from labeled methyl iodide (*C.sup..sctn.H.sub.3I) by reaction with an oxygen nucleophile having a pendant leaving group. The mild and efficient reaction conditions result in good yields of *C.sup..sctn.H.sub.2O with little or no *C isotopic dilution. The simple, efficient production of .sup.11CH.sub.2O is described. The use of the .sup.11CH.sub.2O for the formation of positron emission tomography tracer compounds is described. The reaction can be incorporated into automated equipment available to radiochemistry laboratories. The isotopically labeled formaldehyde can be used in a variety of reactions to provide radiotracer compounds for imaging studies as well as for scintillation counting and autoradiography.

  2. Tentative identification of formaldehyde in the Martian atmosphere

    NASA Astrophysics Data System (ADS)

    Korablev, O. I.; Ackerman, M.; Krasnopolsky, V. A.; Moroz, V. I.; Muller, C.; Rodin, A. V.; Atreya, S. K.

    1993-06-01

    Solar occultation observations of the Martian atmosphere near the limb of the planet were performed during the Phobos mission by means of the Auguste infrared spectrometer in the ranges 2707-2740 and 5392-5272/cm with a resolving power of approximately = 1300. The spectra exhibit features at 2710 and 2730/cm which have not been identified previously. After applying a set of corrections to the data and examining the spectra of various molecules, we are led to conclude that the best candidate for the above-mentioned features is formaldehyde (CH2O). It was observed in eight of the nine successful occultation sequences, mainly between 8 and 20 km with an average mixing ratio of 0.5 (+0.8, - 0.3) ppm (there are no good data below 8 km). The observations are performed in equatorial spring conditions. The altitude distribution of formaldehyde reveals correlation with the permanent haze opacity.

  3. Molecularly Imprinted Polymer Nanoparticles for Formaldehyde Sensing with QCM

    PubMed Central

    Hussain, Munawar; Kotova, Kira; Lieberzeit, Peter A.

    2016-01-01

    Herein, we report on molecularly imprinted polymers (MIPs) for detecting formaldehyde vapors in air streams. A copolymer thin film consisting of styrene, methacrylic acid, and ethylene glycol dimethacrylate on quartz crystal microbalance (QCM) yielded a detection limit of 500 ppb formaldehyde in dry air. Surprisingly, these MIPs showed specific behavior when tested against a range of volatile organic compounds (VOCs), such as acetaldehyde, methanol, formic acid, and dichloromethane. Despite thus being a suitable receptor in principle, the MIPs were not useful for measurements at 50% humidity due to surface saturation by water. This was overcome by introducing primary amino groups into the polymer via allyl amine and by changing the coating morphology from thin film to nanoparticles. This led to the same limit of detection (500 ppb) and selectivity as before, but at the real-life conditions of 50% relative humidity. PMID:27376287

  4. Formaldehyde and Glyoxal: New Products in the SCIAMACHY Operational Processor

    NASA Astrophysics Data System (ADS)

    Hrechanyy, Serhiy; de Smedt, Isabelle; Kretschel, Klaus; Lichtenberg, Günter; Meringer, Markus; Wittrock, Folkard

    In sommer of 2010 version 6 of the SCIAMACHY operational processor is planned to be deliv-ered to ESA. The SCIAMACHY Quality Working Group recommended an implementation of the formalde-hyde (HCHO) and glyoxal (CHOCHO) vertical columns into version 6 of the off-line processor. They are formed during the oxidation of volatile organic compounds (VOCs) emitted by plants, anthropogenic activities, and biomass burning. Due to a rather short lifetime of formaldehyde and glyoxal, their distribution maps, obtained by the SCIAMACHY, represent the emission fields of their precursors, VOCs. The descriptions of reference algorithm as well as all the cross-sections for formaldehyde and glyoxal retrievals were delivered to DLR by the Belgian Institute for Space Aeronomy (BIRA) (I. De Smedt, 2008) and by the IUP (F. Wittrock, 2006), respectively. Both retrievals are based on the DOAS technique. For the formaldehyde retrieval the spectral region of 328.5-346 nm was recommended. The absorption cross-sections of HCHO, O3, NO2, BrO, OClO, a Ring spectrum and a polynomial of the fifth order are included into the fitting procedure. Before conversion to the vertical columns, the slant columns have to be normal-ized by subtracting the slant columns measured over Pacific ocean, where the only source of formaldehyde is methane oxidation. After the conversion to the vertical columns, part of HCHO removed during the previous procedure has to be re-added to the final vertical column by adding of the mean vertical column calculated by the tropospheric chemistry model IMAGES (J.-F. Müller, 1995). This normalization is necessary to compensate for the offset introduced by the solar reference measurements and interferences by other absorbers. For the determination of glyoxal columns, the spectral region 435-457 nm was selected. In this case, the absorption cross-sections of CHOCHO, O3, NO2, H2O, O4, a Ring spectrum and a cubic polynomial are included in the fitting procedure. The normalization of

  5. Phase Space Structures Explain Hydrogen Atom Roaming in Formaldehyde Decomposition.

    PubMed

    Mauguière, Frédéric A L; Collins, Peter; Kramer, Zeb C; Carpenter, Barry K; Ezra, Gregory S; Farantos, Stavros C; Wiggins, Stephen

    2015-10-15

    We re-examine the prototypical roaming reaction--hydrogen atom roaming in formaldehyde decomposition--from a phase space perspective. Specifically, we address the question "why do trajectories roam, rather than dissociate through the radical channel?" We describe and compute the phase space structures that define and control all possible reactive events for this reaction, as well as provide a dynamically exact description of the roaming region in phase space. Using these phase space constructs, we show that in the roaming region, there is an unstable periodic orbit whose stable and unstable manifolds define a conduit that both encompasses all roaming trajectories exiting the formaldehyde well and shepherds them toward the H2···CO well. PMID:26499774

  6. Intercomparison of Formaldehyde Measurements during BEACHON ROCS 2010

    NASA Astrophysics Data System (ADS)

    Kaser, L.; Digangi, J. P.; Schnitzhofer, R.; Herdlinger-Blatt, I. S.; Karl, T.; Graus, M.; Turnipseed, A.; Keutsch, F. N.; Hansel, A.; Beachon-Rocs Science Team

    2011-12-01

    The BEACHON (Biosphere-hydrosphere-atmosphere-interactions of Energy, Aerosols, Carbon, H2O, Organics and Nitrogen) long term research initiative was established to shed light on sources, sinks and the atmospheric fate of organic aerosol and precursor gases. The BEACHON-Rocky mountain Organic Carbon Study (BEACHON-ROCS) focused on the biosphere-atmosphere exchange of reactive organic gases in a rural coniferous forest northwest of Colorado Springs, CO, during August 2010. Formaldehyde (HCHO) is an important tracer of VOC oxidation as it is formed during atmospheric oxidation of biogenic VOCs such as isoprene and other terpenes. Here we present measurements of formaldehyde conducted by two independent instruments, the Madison Fiber Laser Induced Flourescence (FILIF) Instrument and a Proton Transfer Reaction Time of Flight mass spectrometer (PTR-TOF-MS). Both instruments simultaneously measured HCHO concentrations at high temporal resolution potentially allowing for eddy covariance flux calculations. The comparison between FILIF and PTR-TOF-MS suggests generally good agreement.

  7. Molecularly Imprinted Polymer Nanoparticles for Formaldehyde Sensing with QCM.

    PubMed

    Hussain, Munawar; Kotova, Kira; Lieberzeit, Peter A

    2016-01-01

    Herein, we report on molecularly imprinted polymers (MIPs) for detecting formaldehyde vapors in air streams. A copolymer thin film consisting of styrene, methacrylic acid, and ethylene glycol dimethacrylate on quartz crystal microbalance (QCM) yielded a detection limit of 500 ppb formaldehyde in dry air. Surprisingly, these MIPs showed specific behavior when tested against a range of volatile organic compounds (VOCs), such as acetaldehyde, methanol, formic acid, and dichloromethane. Despite thus being a suitable receptor in principle, the MIPs were not useful for measurements at 50% humidity due to surface saturation by water. This was overcome by introducing primary amino groups into the polymer via allyl amine and by changing the coating morphology from thin film to nanoparticles. This led to the same limit of detection (500 ppb) and selectivity as before, but at the real-life conditions of 50% relative humidity. PMID:27376287

  8. Observations of formaldehyde in Comet Machholtz (1988j)

    NASA Technical Reports Server (NTRS)

    Snyder, Lewis E.; Palmer, Patrick; De Pater, Imke

    1990-01-01

    Comet Machholtz's 1(11)-1(10) formaldehyde emission was detected with the VLA in September, 1988 at 6-cm wavelength; the small blueshift of -0.76 + or - 0.40 km/sec noted by these observations is consistent with an anisotropic outgassing of the cometary nucleus in the solar direction. The derived formaldehyde production rate for Comet Halley, which exhibits a similar emission line blueshift, was 1.5 x 10 to the 28th mol/sec, while for Comet Machholtz the production rate is about an order of magnitude higher, at 2 x 10 to the 29th mol/sec. The fading of Comet Machholtz after these observations is ascribed to its breakup.

  9. Tentative identification of formaldehyde in the Martian atmosphere

    NASA Technical Reports Server (NTRS)

    Korablev, O. I.; Ackerman, M.; Krasnopolsky, V. A.; Moroz, V. I.; Muller, C.; Rodin, A. V.; Atreya, S. K.

    1993-01-01

    Solar occultation observations of the Martian atmosphere near the limb of the planet were performed during the Phobos mission by means of the Auguste infrared spectrometer in the ranges 2707-2740 and 5392-5272/cm with a resolving power of approximately = 1300. The spectra exhibit features at 2710 and 2730/cm which have not been identified previously. After applying a set of corrections to the data and examining the spectra of various molecules, we are led to conclude that the best candidate for the above-mentioned features is formaldehyde (CH2O). It was observed in eight of the nine successful occultation sequences, mainly between 8 and 20 km with an average mixing ratio of 0.5 (+0.8, - 0.3) ppm (there are no good data below 8 km). The observations are performed in equatorial spring conditions. The altitude distribution of formaldehyde reveals correlation with the permanent haze opacity.

  10. Asymmetric Aldol Reaction with Formaldehyde: a Challenging Process.

    PubMed

    Meninno, Sara; Lattanzi, Alessandra

    2016-08-01

    The asymmetric aldol reaction with formaldehyde is a fundamental carbon-carbon bond-forming reaction in organic synthesis, as well as in the quest of the origin of life, as it is thought to have been the first "molecular brick" involved in the synthetic path to complex sugars. Products of aldol reactions, i.e., the β-hydroxy carbonyl compounds, are versatile building blocks used to access a great variety of functionalised molecules. The employment of formaldehyde, as a C1 symmetric electrophile, in aldol reactions can be likely considered the most challenging, yet simplest, process to introduce a hydroxymethyl group in an asymmetric fashion. In this account, an overview of the progress achieved in the asymmetric metal- and organocatalysed aldol reaction, using readily available formalin or paraformaldehyde sources, is illustrated. Our recent contribution to this area, with the application of asymmetric hydroxymethylation in cascade processes for the synthesis of γ-butyrolactones, is also shown. PMID:27328802

  11. Enzymatic synthesis of C-11 formaldehyde: concise communication

    SciTech Connect

    Slegers, G.; Lambrecht, R.H.D.; Vandewalle, T.; Meulewaeter, L.; Vandecasteele, C.

    1984-03-01

    An enzymatic synthesis of C-11 formaldehyde from C-11 methanol is presented, with immobilized alcohol oxidase and catalase: a rapid, simple procedure, with a high and reproducible yield. Carbon-11 methanol is oxidized to C-11 formaldehyde by passage over a column on which the enzymes alcohol oxidase and catalase are immobilized. The catalase increases reaction velocity by recycling the oxygen, and prevents destruction of the alcohol oxidase by eliminating the excess of hydrogen peroxide. The yield of the enzyme-catalyzed oxidation was 80-95%. A specific activity of 400-450 mCi/..mu..mole was obtained at EOB + 20 min. Various immobilization techniques and the optimal reaction conditions of the immobilized enzymes are investigated.

  12. Terahertz spectroscopy of deuterated formaldehyde using a frequency multiplication chain

    NASA Astrophysics Data System (ADS)

    Zakharenko, Olena; Motiyenko, Roman A.; Margulès, Laurent; Huet, Thérèse R.

    2015-11-01

    The rotational spectra of deuterated formaldehyde HDCO and D2CO were recorded between 1.1 and 1.52 THz in order to benchmark new terahertz frequency multiplication chain used in the Lille spectrometer. Important spectrometer parameters such as sensitivity, measurement accuracy, and harmonic composition of the radiation source have been tested using the newly measured spectra. For each of the main deuterated isotopic species of formaldehyde the existent datasets from high resolution measurements were augmented by more than 300 new distinct transition frequencies. Most of these frequencies were measured with an accuracy better than 30 kHz. In addition, the high sensitivity of the spectrometer provided by the new frequency multiplication chain allowed observation, assignment and analysis of 13C, 17O, 18O, and 13C18O isotopic species of HDCO and D2CO. For some of these isotopologues the rotational parameters were determined for the first time.

  13. Idiopathic intracranial hypertension, hormones, and 11β-hydroxysteroid dehydrogenases

    PubMed Central

    Markey, Keira A; Uldall, Maria; Botfield, Hannah; Cato, Liam D; Miah, Mohammed A L; Hassan-Smith, Ghaniah; Jensen, Rigmor H; Gonzalez, Ana M; Sinclair, Alexandra J

    2016-01-01

    Idiopathic intracranial hypertension (IIH) results in raised intracranial pressure (ICP) leading to papilledema, visual dysfunction, and headaches. Obese females of reproductive age are predominantly affected, but the underlying pathological mechanisms behind IIH remain unknown. This review provides an overview of pathogenic factors that could result in IIH with particular focus on hormones and the impact of obesity, including its role in neuroendocrine signaling and driving inflammation. Despite occurring almost exclusively in obese women, there have been a few studies evaluating the mechanisms by which hormones and adipokines exert their effects on ICP regulation in IIH. Research involving 11β-hydroxysteroid dehydrogenase type 1, a modulator of glucocorticoids, suggests a potential role in IIH. Improved understanding of the complex interplay between adipose signaling factors such as adipokines, steroid hormones, and ICP regulation may be key to the understanding and future management of IIH. PMID:27186074

  14. A cucurbit[5]uril analogue from dimethylpropanediurea-formaldehyde condensation.

    PubMed

    Jiang, Xiaoqing; Yao, Xuyang; Huang, Xinghua; Wang, Qiaochun; Tian, He

    2015-02-18

    A new host was prepared for the first time from propanediurea-formaldehyde condensation. is soluble in both water and common organic solvents, and binds protonated amines in a 1 : 2 stoichiometry in H2O with the K1 and K2 values on the order of 10(3) M(-1). The self-assembly of with 1,4-xylylene diamine dihydrochloride results in the formation of a linear supramolecular polymer. PMID:25582698

  15. Formaldehyde monitoring program: development of sampling and analysis procedures

    SciTech Connect

    Matthews, T. G.; Hawthorne, A. R.

    1980-01-01

    This report outlines the scope and goals of the formaldehyde analysis program being carried out in Health and Safety Research Division of the Oak Ridge National Laboratory under contract of the US Consumer Product Safety Commission. The outline of the sampling and analysis techniques under consideration, with reference to a time frame for developmental work and field application, is discussed. The complexity of the different techniques is addressed in instances where technical staff would be requird for accurate operation of the instrumentation.

  16. SONEX-Hydrogen Peroxide, Methylhydroperoxide and Formaldehyde Measurements

    NASA Technical Reports Server (NTRS)

    Heikes, Brian

    1999-01-01

    We measured gas phase H2O2, CH3OOH, and CH2O on board the NASA DC-8 during the SONEX field mission, presented preliminary results at three scientific meetings, participated in two data workshops and contributed to joint publications of final results. The observations of peroxides and formaldehyde were instrumental in assessing odd-hydrogen radical chemistry, ozone chemistry, and in tracing meteorological transport paths.

  17. MCSCF potential energy surface for photodissociation of formaldehyde

    NASA Technical Reports Server (NTRS)

    Jaffe, R. L.; Morokuma, K.

    1976-01-01

    The ground state potential energy surface for the dissociation of formaldehyde (H2CO to H2 and CO) is calculated with the ab initio MCSCF method with an extended (4-31G) basis set. The location, barrier height, and force constants of the transition state are determined, and the normal coordinate analysis is carried out. The calculated barrier height is 4.5 eV. Based on the calculated quantities, the detailed mechanism of the photochemical dissociation is discussed.

  18. Testing a steam-formaldehyde sterilizer for gas penetration efficiency

    PubMed Central

    Line, Stuart J.; Pickerill, J. K.

    1973-01-01

    A test piece is described for monitoring the performance of low-temperature steam-with-formaldehyde sterilizers. Comparative tests have shown it to be more difficult to penetrate than an arterial catheter when exposed to the same sterilizing conditions. It is permanent and simple to use and maintain. The growth or non-growth of bacterial spores, in the convenient form of spore strips, is used to indicate the efficacy of sterilization. PMID:4752414

  19. Biodegradation of polystyrene, poly(metnyl methacrylate), and phenol formaldehyde.

    PubMed Central

    Kaplan, D L; Hartenstein, R; Sutter, J

    1979-01-01

    The biodegradation of three synthetic 14C-labeled polymers, poly(methyl methacrylate), phenol formaldehyde, and polystyrene, was studied with 17 species of fungi in axenic cultures, five groups of soil invertebrates, and a variety of mixed microbial communities including sludges, soils, manures, garbages, and decaying plastics. Extremely low decomposition rates were found. The addition of cellulose and mineral failed to increase decomposition rates significantly. PMID:533278

  20. The Gas-Phase Deuterium Fractionation of Formaldehyde

    NASA Astrophysics Data System (ADS)

    Osamura, Yoshihiro; Roberts, Helen; Herbst, Eric

    2005-03-01

    The dominant mechanism for the deuteration of formaldehyde in the gas phase of low-temperature interstellar cloud cores occurs via reaction with the deuterating ions H2D+, HD+2, and D+3. Until now, it has been assumed that deuteration leads to an ion that, on recombination with electrons, can produce a deuterated neutral species with a statistical branching fraction. Quantum chemical calculations reported here, however, show an entirely different picture, in which the deuteration of formaldehyde leads to the molecular ion H2COD+, where the deuterium binds only on the oxygen side of the molecule. The structure is quite stable, while an alternative structure, H2DCO+, cannot be produced in a straightforward manner. Dissociative recombination of H2COD+ to reproduce a formaldehyde structure then removes the deuteration if the dissociation is direct, i.e., it occurs without change of structure. There are several possible indirect mechanisms by which dissociative recombination can lead to HDCO, however. For example, if the direct products are HCOD+H, it is possible that subsequent isomerization to HDCO can occur, although this involved process is unlikely. Another possibility is isomerization during the actual dissociation of the H2COD intermediate. Models of deuterium fractionation in which dissociative recombination is predominantly direct are presented, and it is found that the deuterium fractionation of formaldehyde to form both HDCO and D2CO can still occur via other mechanisms, although with less efficiency than previously obtained. If the dissociative recombination is half indirect, however, then we can recover the previously calculated efficiency.

  1. Thermodynamics of the formaldehyde-water and formaldehyde-ice systems for atmospheric applications.

    PubMed

    Barret, Manuel; Houdier, Stephan; Domine, Florent

    2011-01-27

    Formaldehyde (HCHO) is a species involved in numerous key atmospheric chemistry processes that can significantly impact the oxidative capacity of the atmosphere. Since gaseous HCHO is soluble in water, the water droplets of clouds and the ice crystals of snow exchange HCHO with the gas phase and the partitioning of HCHO between the air, water, and ice phases must be known to understand its chemistry. This study proposes thermodynamic formulations for the partitioning of HCHO between the gas phase and the ice and liquid water phases. A reanalysis of existing data on the vapor-liquid equilibrium has shown the inadequacy of the Henry's law formulation, and we instead propose the following equation to predict the mole fraction of HCHO in liquid water at equilibrium, X(HCHO,liq), as a function of the partial pressure P(HCHO) (Pa) and temperature T (K): X(HCHO,liq) = 1.700 × 10(-15) e((8014/T))(P(HCHO))(1.105). Given the paucity of data on the gas-ice equilibrium, the solubility of HCHO and the diffusion coefficient (D(HCHO)) in ice were measured by exposing large single ice crystals to low P(HCHO). Our recommended value for D(HCHO) over the temperature range 243-266 K is D(HCHO) = 6 × 10(-12) cm(2) s(-1). The solubility of HCHO in ice follows the relationship X(HCHO,ice) = 9.898 × 10(-13) e((4072/T))(P(HCHO))(0.803). Extrapolation of these data yields the P(HCHO) versus 1/T phase diagram for the H(2)O-HCHO system. The comparison of our results to existing data on the partitioning of HCHO between the snow and the atmosphere in the high arctic highlights the interplay between thermodynamic equilibrium and kinetics processes in natural systems. PMID:21171657

  2. Formaldehyde Distribution over North America: Implications for Satellite Retrievals of Formaldehyde Columns and Isoprene Emission

    NASA Technical Reports Server (NTRS)

    Millet, Dylan B.; Jacob, Daniel J.; Turquety, Solene; Hudman, Rynda C.; Wu, Shiliang; Anderson, Bruce E.; Fried, Alan; Walega, James; Heikes, Brian G.; Blake, Donald R.; Singh, Hanwant B.; Clarke, Antony D.

    2006-01-01

    Formaldehyde (HCHO) columns measured from space provide constraints on emissions of volatile organic compounds (VOCs). Quantitative interpretation requires characterization of errors in HCHO column retrievals and relating these columns to VOC emissions. Retrieval error is mainly in the air mass factor (AMF) which relates fitted backscattered radiances to vertical columns and requires external information on HCHO, aerosols, and clouds. Here we use aircraft data collected over North America and the Atlantic to determine the local relationships between HCHO columns and VOC emissions, calculate AMFs for HCHO retrievals, assess the errors in deriving AMFs with a chemical transport model (GEOS-Chem), and draw conclusions regarding space-based mapping of VOC emissions. We show that isoprene drives observed HCHO column variability over North America; HCHO column data from space can thus be used effectively as a proxy for isoprene emission. From observed HCHO and isoprene profiles we find an HCHO molar yield from isoprene oxidation of 1.6 +/- 0.5, consistent with current chemical mechanisms. Clouds are the primary error source in the AMF calculation; errors in the HCHO vertical profile and aerosols have comparatively little effect. The mean bias and 1Q uncertainty in the GEOS-Chem AMF calculation increase from <1% and 15% for clear skies to 17% and 24% for half-cloudy scenes. With fitting errors, this gives an overall 1 Q error in HCHO satellite measurements of 25-31%. Retrieval errors, combined with uncertainties in the HCHO yield from isoprene oxidation, result in a 40% (1sigma) error in inferring isoprene emissions from HCHO satellite measurements.

  3. Catalytic purification of wastewaters containing formaldehyde, methyl alcohol, and acetone

    SciTech Connect

    Rachkovskaya, L.N.; Anisiforov, G.I.; Levitskii, E.A.; Kundo, N.N.

    1982-01-10

    A catalytic method for purification of wastewaters containing alcohols, aldehydes, and ketones is described in the literature. A current of steam containing gaseous organic compounds is passed over a complete-oxidation catalyst at temperatures of 250-700/sup 0/C. The organic compounds are oxidized to carbon dioxide. The main drawback of this method is that the wastewater must be evaporated and the vapor heated to high temperatures, involving a high consumption of fuel. Methods of liquid-phase catalytic oxidation under pressure are free from this drawback. A patent describes liquid-phase oxidation of phenol, analine, nitrobenzene, glycol, and dimethylformamide at temperatures of 275-300/sup 0/C under air pressures up to 100 atm in presence of oxides of copper, chromium, and zinc; a metallic catalyst consisting of copper, chromium, and manganese; copper oxide deposited on magnesium silicate. In a contact time of 8-10 min the degree of oxidation is 90-99%. It is known that liquid-phase oxidation of formaldehyde without a catalyst at 200/sup 0/C and 120 atm with a contact time of 4 h results in 80% oxidation of formaldehyde to methyl formate undergoes 10% conversion into acetic acid, while methyl alcohol is not oxidized at all. In this communication we describe liquid-phase catalytic oxidation of model wastewater containing formaldehyde, methyl alcohol, and acetone at temperatures up to 250/sup 0/C and oxygen pressures up to 20 atm.

  4. Formaldehyde and acetaldehyde emissions from residential wood combustion in Portugal

    NASA Astrophysics Data System (ADS)

    Cerqueira, Mário; Gomes, Luís; Tarelho, Luís; Pio, Casimiro

    2013-06-01

    A series of experiments were conducted to characterize formaldehyde and acetaldehyde emissions from residential combustion of common wood species growing in Portugal. Five types of wood were investigated: maritime pine (Pinus pinaster), eucalyptus (Eucalyptus globulus), cork oak (Quercus suber), holm oak (Quercus rotundifolia) and pyrenean oak (Quercus pyrenaica). Laboratory experiments were performed with a typical wood stove used for domestic heating in Portugal and operating under realistic home conditions. Aldehydes were sampled from diluted combustion flue gas using silica cartridges coated with 2,4-dinitrophenylhydrazine and analyzed by high performance liquid chromatography with diode array detection. The average formaldehyde to acetaldehyde concentration ratio (molar basis) in the stove flue gas was in the range of 2.1-2.9. Among the tested wood types, pyrenean oak produced the highest emissions for both formaldehyde and acetaldehyde: 1772 ± 649 and 1110 ± 454 mg kg-1 biomass burned (dry basis), respectively. By contrast, maritime pine produced the lowest emissions: 653 ± 151 and 371 ± 162 mg kg-1 biomass (dry basis) burned, respectively. Aldehydes were sampled separately during distinct periods of the holm oak wood combustion cycles. Significant variations in the flue gas concentrations were found, with higher values measured during the devolatilization stage than in the flaming and smoldering stages.

  5. A brief review of control measures for indoor formaldehyde

    SciTech Connect

    Matthews, T.G.

    1988-01-01

    Indoor environments contain a variety of consumer and construction products that emit formaldehyde (CH/sub 2/O) vapor. The strongest CH/sub 2/O emitters are typically particleboard underlayment and industrial particleboard, hardwood plywood paneling, urea-formaldehyde foam insulation, and medium density fiberboard, all of which contain urea-formaldehyde (UF) resins. The contribution of individual products to indoor CH/sub 2/O levels depends on several parameters, including the quantity and age of the product, building ventilation rate, presence of permeation barriers, temperature (T), relative humidity (RH), and CH/sub 2/O vapor concentration resulting from all of the CH/sub 2/O emitters (1,3-8). Combustion sources (e.g., kerosene heaters, gas stoves and cigarettes), carpet and carpet padding, resilient flooring (e.g., linoleum), gypsum board, non-apparel and apparel textiles, ceiling tiles, fibrous glass insulation and softwood plywood subflooring are generally weak emitters that do not contribute significantly to steady-state, indoor CH/sub 2/O levels. Control measures exist to reduce CH/sub 2/O emissions from consumer and construction products during their manufacturer and in post-installation applications. This note summarized the effectiveness of the following subset of post-installation control measures: product aging, installations of permeation barriers (i.e., flooring) and increased building ventilation. 14 refs.

  6. Low-density carbonized resorcinol-formaldehyde foams. Final report

    SciTech Connect

    Kong, F.M.; Buckley, S.R.; Giles, C.L. Jr.; Haendler, B.L.; Hair, L.M.; Letts, S.A.; Overturf, G.E. III; Price, C.W.; Cook, R.C.

    1991-07-04

    This report documents research and development on resorcinol- formaldehyde-based foam materials conducted between 1986 and June 1990, when the effort was discontinued. The foams discussed are resorcinol-formaldehyde (RF) foam, carbonized RF (CRF) foam, and two composite foams, a polystyrene/RF (PS/RF) foam and its carbonized derivative (CPR). The RF foams are synthesized by the polycondensation of resorcinol with formaldehyde in a slightly basic solution. Their structure and density depend strongly on the concentration of the sodium carbonate catalyst. The have an interconnected bead structure similar to that of silica aerogels; bead sizes range from 30 to 130 {Angstrom}, and cell sizes are less than 0.1 {mu}m. We have achieved densities of 16 to 200 mg/cm{sup 3}. The RF foams can be pyrolyzed in an inert atmosphere to form a vitreous carbon foam (CRF), which has a similar microstructure but much higher mechanical strength. The PS/RF foams are obtained by filling the 2- to 3-{mu}m cells of PS foam (a low-density hydrocarbon foam we have developed) with RF. The resultant foams have the outstanding handling and machinability of the PS foam matrix and the small cell size of RF. Pyrolyzing PS/RF foams causes depolymerization and loss of the PS; the resulting CPR foams have a structure similar to the PS foams in which CRF both replicates and fills the PS cells.

  7. Low-density carbonized resorcinol-formaldehyde foams

    SciTech Connect

    Kong, F.M.; Buckley, S.R.; Giles, C.L. Jr.; Haendler, B.L.; Hair, L.M.; Letts, S.A.; Overturf, G.E. III; Price, C.W.; Cook, R.C.

    1991-07-04

    This report documents research and development on resorcinol- formaldehyde-based foam materials conducted between 1986 and June 1990, when the effort was discontinued. The foams discussed are resorcinol-formaldehyde (RF) foam, carbonized RF (CRF) foam, and two composite foams, a polystyrene/RF (PS/RF) foam and its carbonized derivative (CPR). The RF foams are synthesized by the polycondensation of resorcinol with formaldehyde in a slightly basic solution. Their structure and density depend strongly on the concentration of the sodium carbonate catalyst. The have an interconnected bead structure similar to that of silica aerogels; bead sizes range from 30 to 130 {Angstrom}, and cell sizes are less than 0.1 {mu}m. We have achieved densities of 16 to 200 mg/cm{sup 3}. The RF foams can be pyrolyzed in an inert atmosphere to form a vitreous carbon foam (CRF), which has a similar microstructure but much higher mechanical strength. The PS/RF foams are obtained by filling the 2- to 3-{mu}m cells of PS foam (a low-density hydrocarbon foam we have developed) with RF. The resultant foams have the outstanding handling and machinability of the PS foam matrix and the small cell size of RF. Pyrolyzing PS/RF foams causes depolymerization and loss of the PS; the resulting CPR foams have a structure similar to the PS foams in which CRF both replicates and fills the PS cells.

  8. Physicochemical behavior of sulphonated acetone-formaldehyde resin and naphthalene sulfonate-formaldehyde condensate in coal-water interface

    SciTech Connect

    Zhou, M.S.; Qiu, X.Q.; Yang, D.J.; Ouyang, X.P.

    2009-07-01

    This article studies the physicochemical characteristic of two anionic dispersants sulphonated acetone-formaldehyde resin (SAF) and naphthalene sulfonate-formaldehyde condensate (FDN) at coal-water interface, including contact angle, adsorption amount, thickness of adsorbed film, and zeta potential, using four different ranks of coals. The results show that SAF has better wetting property than FDN on coal surface. The adsorption amount of SAF in coal-water interface is greater than that of FDN, and that the thickness of adsorbed films of SAF and FDN on Datong coal measured by x-ray photoelectron spectroscopy (XPS) are respectively 6.38nm and 2.11nm. Moreover, the measurements of zeta potentials in coal-water interface show that SAF has greater capacity in charging coal surface with electronegativity. Based on the investigation, the adsorption models of SAF and FDN on different rank of coals are presented.

  9. Protection against avian necrotic enteritis after immunisation with NetB genetic or formaldehyde toxoids☆

    PubMed Central

    Fernandes da Costa, Sérgio P.; Mot, Dorien; Bokori-Brown, Monika; Savva, Christos G.; Basak, Ajit K.; Van Immerseel, Filip; Titball, Richard W.

    2013-01-01

    NetB (necrotic enteritis toxin B) is a recently identified β-pore-forming toxin produced by Clostridium perfringens. This toxin has been shown to play a major role in avian necrotic enteritis. In recent years, a dramatic increase in necrotic enteritis has been observed, especially in countries where the use of antimicrobial growth promoters in animal feedstuffs has been banned. The aim of this work was to determine whether immunisation with a NetB toxoid would provide protection against necrotic enteritis. The immunisation of poultry with a formaldehyde NetB toxoid or with a NetB genetic toxoid (W262A) resulted in the induction of antibody responses against NetB and provided partial protection against disease. PMID:23727000

  10. Engineering of Pyranose Dehydrogenase for Increased Oxygen Reactivity

    PubMed Central

    Krondorfer, Iris; Lipp, Katharina; Brugger, Dagmar; Staudigl, Petra; Sygmund, Christoph; Haltrich, Dietmar; Peterbauer, Clemens K.

    2014-01-01

    Pyranose dehydrogenase (PDH), a member of the GMC family of flavoproteins, shows a very broad sugar substrate specificity but is limited to a narrow range of electron acceptors and reacts extremely slowly with dioxygen as acceptor. The use of substituted quinones or (organo)metals as electron acceptors is undesirable for many production processes, especially of food ingredients. To improve the oxygen reactivity, site-saturation mutagenesis libraries of twelve amino acids around the active site of Agaricus meleagris PDH were expressed in Saccharomyces cerevisiae. We established high-throughput screening assays for oxygen reactivity and standard dehydrogenase activity using an indirect Amplex Red/horseradish peroxidase and a DCIP/D-glucose based approach. The low number of active clones confirmed the catalytic role of H512 and H556. Only one position was found to display increased oxygen reactivity. Histidine 103, carrying the covalently linked FAD cofactor in the wild-type, was substituted by tyrosine, phenylalanine, tryptophan and methionine. Variant H103Y was produced in Pichia pastoris and characterized and revealed a five-fold increase of the oxygen reactivity. PMID:24614932

  11. Formaldehyde concentrations in household air of asthma patients determined using colorimetric detector tubes

    PubMed Central

    Dannemiller, Karen C.; Murphy, Johnna S.; Dixon, Sherry L.; Pennell, Kelly G.; Suuberg, Eric M.; Jacobs, David E.; Sandel, Megan

    2013-01-01

    Formaldehyde is a colorless, pungent gas commonly found in homes that is a respiratory irritant, sensitizer, carcinogen and asthma trigger. Typical household sources include plywood and particleboard, cleaners, cosmetics, pesticides, and others. Development of a fast and simple measurement technique could facilitate continued research on this important chemical. The goal of this research is to apply an inexpensive short-term measurement method to find correlations between formaldehyde sources and concentration, and formaldehyde concentration and asthma control. Formaldehyde was measured using 30-minute grab samples in length-of-stain detector tubes in homes (n=70) of asthmatics in the Boston, MA area. Clinical status and potential formaldehyde sources were determined. The geometric mean formaldehyde level was 35.1 ppb and ranged from 5–132 ppb. Based on one-way ANOVA, t-tests, and linear regression, predictors of log-transformed formaldehyde concentration included absolute humidity, season, and the presence of decorative laminates, fiberglass, or permanent press fabrics (p<0.05), as well as temperature and household cleaner use (p<0.10). The geometric mean formaldehyde concentration was 57% higher in homes of children with very poorly controlled asthma compared to homes of other asthmatic children (p=0.078). This study provides a simple method for measuring household formaldehyde and suggests that exposure is related to poorly controlled asthma. PMID:23278296

  12. Possible prebiotic synthesis of monosaccharides from formaldehyde in presence of phosphates

    NASA Astrophysics Data System (ADS)

    Simonov, A. N.; Pestunova, O. P.; Matvienko, L. G.; Snytnikov, V. N.; Snytnikova, O. A.; Tsentalovich, Yu. P.; Parmon, V. N.

    Condensation of formaldehyde and lower carbohydrates (glycolaldehyde, glyceraldehyde, and dihydroxyacetone) is effectively catalyzed by heterogeneous and homogeneous phosphates in neutral aqueous medium. The interaction of formaldehyde and dihydroxyacetone leads to the preferential formation of 3-pentulose and erythrulose with yields of 40% and 45%, respectively. In absence of formaldehyde, the condensation of glycolaldehyde and glyceraldehyde catalyzed by phosphates leads to the formation of ribose and fructose. We demonstrate the possibility of formation of higher monosaccharides from pure formaldehyde in the course of the combined photochemical and phosphate-catalyzed reactions in plausible prebiotic conditions.

  13. Formaldehyde concentrations in household air of asthma patients determined using colorimetric detector tubes.

    PubMed

    Dannemiller, K C; Murphy, J S; Dixon, S L; Pennell, K G; Suuberg, E M; Jacobs, D E; Sandel, M

    2013-08-01

    Formaldehyde is a colorless, pungent gas commonly found in homes and is a respiratory irritant, sensitizer, carcinogen, and asthma trigger. Typical household sources include plywood and particleboard, cleaners, cosmetics, pesticides, and others. Development of a fast and simple measurement technique could facilitate continued research on this important chemical. The goal of this research is to apply an inexpensive short-term measurement method to find correlations between formaldehyde sources and concentration, and formaldehyde concentration and asthma control. Formaldehyde was measured using 30-min grab samples in length-of-stain detector tubes in homes (n = 70) of asthmatics in the Boston, MA area. Clinical status and potential formaldehyde sources were determined. The geometric mean formaldehyde level was 35.1 ppb and ranged from 5 to 132 ppb. Based on one-way ANOVA, t-tests, and linear regression, predictors of log-transformed formaldehyde concentration included absolute humidity, season, and the presence of decorative laminates, fiberglass, or permanent press fabrics (P < 0.05), as well as temperature and household cleaner use (P < 0.10). The geometric mean formaldehyde concentration was 57% higher in homes of children with very poorly controlled asthma compared to homes of other asthmatic children (P = 0.078). This study provides a simple method for measuring household formaldehyde and suggests that exposure is related to poorly controlled asthma. PMID:23278296

  14. A Formaldehyde Exposure Assessment Tool for Occupants of FEMA Temporary Housing Units

    SciTech Connect

    Parthasarathy, Srinandini; Spears, Michael; Maddalena, Randy L.; Russell, Marion L; Apte, Michael G.

    2010-10-01

    The report outlines the methodology used to develop a web-based tool to assess the formaldehyde exposure of the occupants of Federal Emergency Management Administration (FEMA) temporary housing units (THUs) after Hurricanes Katrina and Rita in 2005. Linear regression models were built using available data to retrospectively estimate the indoor temperature and relative humidity, formaldehyde emission factors and concentration, and hence the formaldehyde exposures. The interactive web-tool allows the user to define the inputs to the model to evaluate formaldehyde exposures for different scenarios.

  15. Prostaglandin dehydrogenase and the initiation of labor.

    PubMed

    Challis, J R; Patel, F A; Pomini, F

    1999-01-01

    In summary, these studies have suggested that prostaglandin dehydrogenase may have a central role to play in the mechanisms which determine biologically active prostaglandin concentrations within human fetal membranes and placenta at the time of labor, at term or preterm. Moreover, our studies indicate that the regulation of PGDH may by multifactorial (figure 3). In certain regions of the membranes, we suggest that PGDH expression may be influenced by levels of anti-inflammatory and pro-inflammatory cytokines. In other regions of the membranes, we suggest that PGDH may be regulated at a transcriptional level by competing activities of progesterone and cortisol. The action of progesterone could be effected through systemically-derived steroid, or by locally synthesized steroid, acting in a paracrine and/or autocrine fashion. The effects of cortisol in placenta must be due to glucocorticoid derived from the maternal or fetal compartment, since the placenta lacks the hydroxylases required for endogenous cortisol production. However, metabolism of cortisol by 11 beta-HSD-2 reduces the potency of this glucocorticoid in placental tissue. In chorion however, cortisol may be formed locally, from cortisone, in addition to its being derived from the maternal circulation and/or from the amniotic fluid. Our current studies do not allow us to delineate whether the effects of progesterone and cortisol on PGDH are exerted through the glucocorticoid receptor (GR) or progesterone receptor (PR) or both. It is possible that through pregnancy, PGDH activity is maintained by progesterone acting either through low levels of PR in membranes, or, more likely, acting through GR. At term, elevated levels of cortisol compete with and displace progesterone from GR, resulting in inhibition of PGDH transcription and activity. In this way, local withdrawal of progesterone action would be effected within human intrauterine tissues, without requiring changes in systemic, circulating progesterone

  16. Effects of low molecular-weight organic acids and dehydrogenase activity in rhizosphere sediments of mangrove plants on phytoremediation of polycyclic aromatic hydrocarbons.

    PubMed

    Wang, Yuanyuan; Fang, Ling; Lin, Li; Luan, Tiangang; Tam, Nora F Y

    2014-03-01

    This work evaluated the roles of the low-molecular-weight organic acids (LMWOAs) from root exudates and the dehydrogenase activity in the rhizosphere sediments of three mangrove plant species on the removal of mixed PAHs. The results showed that the concentrations of LMWOAs and dehydrogenase activity changed species-specifically with the levels of PAH contamination. In all plant species, the concentration of citric acid was the highest, followed by succinic acid. For these acids, succinic acid was positively related to the removal of all the PAHs except Chr. Positive correlations were also found between the removal percentages of 4-and 5-ring PAHs and all LMWOAs, except citric acid. LMWOAs enhanced dehydrogenase activity, which positively related to PAH removal percentages. These findings suggested that LMWOAs and dehydrogenase activity promoted the removal of PAHs. Among three mangrove plants, Bruguiera gymnorrhiza, the plant with the highest root biomass, dehydrogenase activity and concentrations of LMWOAs, was most efficient in removing PAHs. PMID:24287262

  17. Structure of a bacterial enzyme regulated by phosphorylation, isocitrate dehydrogenase.

    PubMed

    Hurley, J H; Thorsness, P E; Ramalingam, V; Helmers, N H; Koshland, D E; Stroud, R M

    1989-11-01

    The structure of isocitrate dehydrogenase [threo-DS-isocitrate: NADP+ oxidoreductase (decarboxylating), EC 1.1.1.42] from Escherichia coli has been solved and refined at 2.5 A resolution and is topologically different from that of any other dehydrogenase. This enzyme, a dimer of identical 416-residue subunits, is inactivated by phosphorylation at Ser-113, which lies at the edge of an interdomain pocket that also contains many residues conserved between isocitrate dehydrogenase and isopropylmalate dehydrogenase. Isocitrate dehydrogenase contains an unusual clasp-like domain in which both polypeptide chains in the dimer interlock. Based on the structure of isocitrate dehydrogenase and conservation with isopropylmalate dehydrogenase, we suggest that the active site lies in an interdomain pocket close to the phosphorylation site. PMID:2682654

  18. A BIOGENIC ROLE IN EXPOSURE TO TWO TOXIC COMPOUNDS

    EPA Science Inventory

    Biogenic sources play an important role in ozone and particulate concentrations through emissions of volatile organic compounds. The same emissions also contribute to chronic toxic exposures from formaldehyde and acetaldehyde because each compound arises through primary and se...

  19. PQQ-dependent methanol dehydrogenases: rare-earth elements make a difference.

    PubMed

    Keltjens, Jan T; Pol, Arjan; Reimann, Joachim; Op den Camp, Huub J M

    2014-01-01

    Methanol dehydrogenase (MDH) catalyzes the first step in methanol use by methylotrophic bacteria and the second step in methane conversion by methanotrophs. Gram-negative bacteria possess an MDH with pyrroloquinoline quinone (PQQ) as its catalytic center. This MDH belongs to the broad class of eight-bladed β propeller quinoproteins, which comprise a range of other alcohol and aldehyde dehydrogenases. A well-investigated MDH is the heterotetrameric MxaFI-MDH, which is composed of two large catalytic subunits (MxaF) and two small subunits (MxaI). MxaFI-MDHs bind calcium as a cofactor that assists PQQ in catalysis. Genomic analyses indicated the existence of another MDH distantly related to the MxaFI-MDHs. Recently, several of these so-called XoxF-MDHs have been isolated. XoxF-MDHs described thus far are homodimeric proteins lacking the small subunit and possess a rare-earth element (REE) instead of calcium. The presence of such REE may confer XoxF-MDHs a superior catalytic efficiency. Moreover, XoxF-MDHs are able to oxidize methanol to formate, rather than to formaldehyde as MxaFI-MDHs do. While structures of MxaFI- and XoxF-MDH are conserved, also regarding the binding of PQQ, the accommodation of a REE requires the presence of a specific aspartate residue near the catalytic site. XoxF-MDHs containing such REE-binding motif are abundantly present in genomes of methylotrophic and methanotrophic microorganisms and also in organisms that hitherto are not known for such lifestyle. Moreover, sequence analyses suggest that XoxF-MDHs represent only a small part of putative REE-containing quinoproteins, together covering an unexploited potential of metabolic functions. PMID:24816778

  20. S-Nitrosoglutathione is a substrate for rat alcohol dehydrogenase class III isoenzyme.

    PubMed

    Jensen, D E; Belka, G K; Du Bois, G C

    1998-04-15

    An enzyme isolated from rat liver cytosol (native molecular mass 78. 3 kDa; polypeptide molecular mass 42.5 kDa) is capable of catalysing the NADH/NADPH-dependent degradation of S-nitrosoglutathione (GSNO). The activity utilizes 1 mol of coenzyme per mol of GSNO processed. The isolated enzyme has, as well, several characteristics that are unique to alcohol dehydrogenase (ADH) class III isoenzyme: it is capable of catalysing the NAD+-dependent oxidations of octanol (insensitive to inhibition by 4-methylpyrazole), methylcrotyl alcohol (stimulated by added pentanoate) and 12-hydroxydodecanoic acid, and also the NADH/NADPH-dependent reduction of octanal. Methanol and ethanol oxidation activity is minimal. The enzyme has formaldehyde dehydrogenase activity in that it is capable of catalysing the NAD+/NADP+-dependent oxidation of S-hydroxymethylglutathione. Treatment with the arginine-specific reagent phenylglyoxal prevents the pentanoate stimulation of methylcrotyl alcohol oxidation and markedly diminishes the enzymic activity towards octanol, 12-hydroxydodecanoic acid and S-hydroxymethylglutathione; the capacity to catalyse GSNO degradation is also checked. Additionally, limited peptide sequencing indicates 100% correspondence with known ADH class III isoenzyme sequences. Kinetic studies demonstrate that GSNO is an exceptionally active substrate for this enzyme. S-Nitroso-N-acetylpenicillamine and S-nitrosated human serum albumin are not substrates; the activity towards S-nitrosated glutathione mono- and di-ethyl esters is minimal. Product analysis suggests that glutathione sulphinamide is the major stable product of enzymic GSNO processing, with minor yields of GSSG and NH3; GSH, hydroxylamine, nitrite, nitrate and nitric oxide accumulations are minimal. Inclusion of GSH in the reaction mix decreases the yield of the supposed glutathione sulphinamide in favor of GSSG and hydroxylamine. PMID:9531510