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Sample records for arsenate respiratory reductase

  1. Respiratory arsenate reductase as a bidirectional enzyme

    International Nuclear Information System (INIS)

    The haloalkaliphilic bacterium Alkalilimnicola ehrlichii is capable of anaerobic chemolithoautotrophic growth by coupling the oxidation of arsenite (As(III)) to the reduction of nitrate and carbon dioxide. Analysis of its complete genome indicates that it lacks a conventional arsenite oxidase (Aox), but instead possesses two operons that each encode a putative respiratory arsenate reductase (Arr). Here we show that one homolog is expressed under chemolithoautotrophic conditions and exhibits both arsenite oxidase and arsenate reductase activity. We also demonstrate that Arr from two arsenate respiring bacteria, Alkaliphilus oremlandii and Shewanella sp. strain ANA-3, is also biochemically reversible. Thus Arr can function as a reductase or oxidase. Its physiological role in a specific organism, however, may depend on the electron potentials of the molybdenum center and [Fe-S] clusters, additional subunits, or constitution of the electron transfer chain. This versatility further underscores the ubiquity and antiquity of microbial arsenic metabolism.

  2. Respiratory arsenate reductase as a bidirectional enzyme

    Science.gov (United States)

    Richey, C.; Chovanec, P.; Hoeft, S.E.; Oremland, R.S.; Basu, P.; Stolz, J.F.

    2009-01-01

    The haloalkaliphilic bacterium Alkalilimnicola ehrlichii is capable of anaerobic chemolithoautotrophic growth by coupling the oxidation of arsenite (As(III)) to the reduction of nitrate and carbon dioxide. Analysis of its complete genome indicates that it lacks a conventional arsenite oxidase (Aox), but instead possesses two operons that each encode a putative respiratory arsenate reductase (Arr). Here we show that one homolog is expressed under chemolithoautotrophic conditions and exhibits both arsenite oxidase and arsenate reductase activity. We also demonstrate that Arr from two arsenate respiring bacteria, Alkaliphilus oremlandii and Shewanella sp. strain ANA-3, is also biochemically reversible. Thus Arr can function as a reductase or oxidase. Its physiological role in a specific organism, however, may depend on the electron potentials of the molybdenum center and [Fe–S] clusters, additional subunits, or constitution of the electron transfer chain. This versatility further underscores the ubiquity and antiquity of microbial arsenic metabolism.

  3. Genetic identification of a respiratory arsenate reductase

    OpenAIRE

    Saltikov, Chad W.; Newman, Dianne K.

    2003-01-01

    For more than a decade, it has been recognized that arsenate [H2AsO41-; As(V)] can be used by microorganisms as a terminal electron acceptor in anaerobic respiration. Given the toxicity of arsenic, the mechanistic basis of this process is intriguing, as is its evolutionary origin. Here we show that a two-gene cluster (arrAB; arsenate respiratory reduction) in the bacterium Shewanella sp. strain ANA-3 specifically confers respiratory As(V) reductase activity. Mutants with in-frame deletions of...

  4. Characterization of the Arsenate Respiratory Reductase from Shewanella sp. Strain ANA-3

    OpenAIRE

    Malasarn, Davin; Keeffe, Jennifer R.; Newman, Dianne K.

    2008-01-01

    Microbial arsenate respiration contributes to the mobilization of arsenic from the solid to the soluble phase in various locales worldwide. To begin to predict the extent to which As(V) respiration impacts arsenic geochemical cycling, we characterized the expression and activity of the Shewanella sp. strain ANA-3 arsenate respiratory reductase (ARR), the key enzyme involved in this metabolism. ARR is expressed at the beginning of the exponential phase and persists throughout the stationary ph...

  5. The arsenic hyperaccumulating Pteris vittata expresses two arsenate reductases

    OpenAIRE

    Patrizia Cesaro; Chiara Cattaneo; Elisa Bona; Graziella Berta; Maria Cavaletto

    2015-01-01

    Enzymatic reduction of arsenate to arsenite is the first known step in arsenate metabolism in all organisms. Although the presence of one mRNA arsenate reductase (PvACR2) has been characterized in gametophytes of P. vittata, no arsenate reductase protein has been directly observed in this arsenic hyperaccumulating fern, yet. In order to assess the possible presence of arsenate reductase in P. vittata, two recombinant proteins, ACR2-His6 and Trx-His6-S-Pv2.5–8 were prepared in Escherichia coli...

  6. Genome-wide association mapping identifies a new arsenate reductase enzyme critical for limiting arsenic accumulation in plants.

    Directory of Open Access Journals (Sweden)

    Dai-Yin Chao

    2014-12-01

    Full Text Available Inorganic arsenic is a carcinogen, and its ingestion through foods such as rice presents a significant risk to human health. Plants chemically reduce arsenate to arsenite. Using genome-wide association (GWA mapping of loci controlling natural variation in arsenic accumulation in Arabidopsis thaliana allowed us to identify the arsenate reductase required for this reduction, which we named High Arsenic Content 1 (HAC1. Complementation verified the identity of HAC1, and expression in Escherichia coli lacking a functional arsenate reductase confirmed the arsenate reductase activity of HAC1. The HAC1 protein accumulates in the epidermis, the outer cell layer of the root, and also in the pericycle cells surrounding the central vascular tissue. Plants lacking HAC1 lose their ability to efflux arsenite from roots, leading to both increased transport of arsenic into the central vascular tissue and on into the shoot. HAC1 therefore functions to reduce arsenate to arsenite in the outer cell layer of the root, facilitating efflux of arsenic as arsenite back into the soil to limit both its accumulation in the root and transport to the shoot. Arsenate reduction by HAC1 in the pericycle may play a role in limiting arsenic loading into the xylem. Loss of HAC1-encoded arsenic reduction leads to a significant increase in arsenic accumulation in shoots, causing an increased sensitivity to arsenate toxicity. We also confirmed the previous observation that the ACR2 arsenate reductase in A. thaliana plays no detectable role in arsenic metabolism. Furthermore, ACR2 does not interact epistatically with HAC1, since arsenic metabolism in the acr2 hac1 double mutant is disrupted in an identical manner to that described for the hac1 single mutant. Our identification of HAC1 and its associated natural variation provides an important new resource for the development of low arsenic-containing food such as rice.

  7. Phylogenetic analysis of bacterial and archaeal arsC gene sequences suggests an ancient, common origin for arsenate reductase

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    Dugas Sandra L

    2003-07-01

    Full Text Available Abstract Background The ars gene system provides arsenic resistance for a variety of microorganisms and can be chromosomal or plasmid-borne. The arsC gene, which codes for an arsenate reductase is essential for arsenate resistance and transforms arsenate into arsenite, which is extruded from the cell. A survey of GenBank shows that arsC appears to be phylogenetically widespread both in organisms with known arsenic resistance and those organisms that have been sequenced as part of whole genome projects. Results Phylogenetic analysis of aligned arsC sequences shows broad similarities to the established 16S rRNA phylogeny, with separation of bacterial, archaeal, and subsequently eukaryotic arsC genes. However, inconsistencies between arsC and 16S rRNA are apparent for some taxa. Cyanobacteria and some of the γ-Proteobacteria appear to possess arsC genes that are similar to those of Low GC Gram-positive Bacteria, and other isolated taxa possess arsC genes that would not be expected based on known evolutionary relationships. There is no clear separation of plasmid-borne and chromosomal arsC genes, although a number of the Enterobacteriales (γ-Proteobacteria possess similar plasmid-encoded arsC sequences. Conclusion The overall phylogeny of the arsenate reductases suggests a single, early origin of the arsC gene and subsequent sequence divergence to give the distinct arsC classes that exist today. Discrepancies between 16S rRNA and arsC phylogenies support the role of horizontal gene transfer (HGT in the evolution of arsenate reductases, with a number of instances of HGT early in bacterial arsC evolution. Plasmid-borne arsC genes are not monophyletic suggesting multiple cases of chromosomal-plasmid exchange and subsequent HGT. Overall, arsC phylogeny is complex and is likely the result of a number of evolutionary mechanisms.

  8. Arsenate reduction: thiol cascade chemistry with convergent evolution.

    Science.gov (United States)

    Messens, Joris; Silver, Simon

    2006-09-01

    The frequent abundance of arsenic in the environment has guided the evolution of enzymes for the reduction of arsenate. The arsenate reductases (ArsC) from different sources have unrelated sequences and structural folds, and can be divided into different classes on the basis of their structures, reduction mechanisms and the locations of catalytic cysteine residues. The thioredoxin-coupled arsenate reductase class is represented by Staphylococcus aureus pI258 ArsC and Bacillus subtilis ArsC. The ArsC from Escherichia coli plasmid R773 and the eukaryotic ACR2p reductase from Saccharomyces cerevisiae represent two distinct glutaredoxin-linked ArsC classes. All are small cytoplasmic redox enzymes that reduce arsenate to arsenite by the sequential involvement of three different thiolate nucleophiles that function as a redox cascade. In contrast, the ArrAB complex is a bacterial heterodimeric periplasmic or a surface-anchored arsenate reductase that functions as a terminal electron acceptor and transfers electrons from the membrane respiratory chain to arsenate. Finally, the less well documented arsenate reductase activity of the monomeric arsenic(III) methylase, which is an S-adenosylmethionine (AdoMet)-dependent methyltransferase. After each oxidative methylation cycle and before the next methylation step, As(V) is reduced to As(III). Methylation by this enzyme is also considered an arsenic-resistance mechanism for bacteria, fungi and mammals. PMID:16905151

  9. Solution structure of an arsenate reductase-related protein, YffB, from Brucella melitensis, the etiological agent responsible for brucellosis

    International Nuclear Information System (INIS)

    B. melitensis is a NIAID Category B microorganism that is responsible for brucellosis and is a potential agent for biological warfare. Here, the solution structure of the 116-residue arsenate reductase-related protein Bm-YffB (BR0369) from this organism is reported. Brucella melitensis is the etiological agent responsible for brucellosis. Present in the B. melitensis genome is a 116-residue protein related to arsenate reductases (Bm-YffB; BR0369). Arsenate reductases (ArsC) convert arsenate ion (H2AsO4−), a compound that is toxic to bacteria, to arsenite ion (AsO2−), a product that may be efficiently exported out of the cell. Consequently, Bm-YffB is a potential drug target because if arsenate reduction is the protein’s major biological function then disabling the cell’s ability to reduce arsenate would make these cells more sensitive to the deleterious effects of arsenate. Size-exclusion chromatography and NMR spectroscopy indicate that Bm-YffB is a monomer in solution. The solution structure of Bm-YffB shows that the protein consists of two domains: a four-stranded mixed β-sheet flanked by two α-helices on one side and an α-helical bundle. The α/β domain is characteristic of the fold of thioredoxin-like proteins and the overall structure is generally similar to those of known arsenate reductases despite the marginal sequence similarity. Chemical shift perturbation studies with 15N-labeled Bm-YffB show that the protein binds reduced glutathione at a site adjacent to a region similar to the HX3CX3R catalytic sequence motif that is important for arsenic detoxification activity in the classical arsenate-reductase family of proteins. The latter observation supports the hypothesis that the ArsC-YffB family of proteins may function as glutathione-dependent thiol reductases. However, comparison of the structure of Bm-YffB with the structures of proteins from the classical ArsC family suggest that the mechanism and possibly the function of Bm-YffB and other

  10. A SAM-dependent methyltransferase cotranscribed with arsenate reductase alters resistance to peptidyl transferase center-binding antibiotics in Azospirillum brasilense Sp7.

    Science.gov (United States)

    Singh, Sudhir; Singh, Chhaya; Tripathi, Anil Kumar

    2014-05-01

    The genome of Azospirillum brasilense harbors a gene encoding S-adenosylmethionine-dependent methyltransferase, which is located downstream of an arsenate reductase gene. Both genes are cotranscribed and translationally coupled. When they were cloned and expressed individually in an arsenate-sensitive strain of Escherichia coli, arsenate reductase conferred tolerance to arsenate; however, methyltransferase failed to do so. Sequence analysis revealed that methyltransferase was more closely related to a PrmB-type N5-glutamine methyltransferase than to the arsenate detoxifying methyltransferase ArsM. Insertional inactivation of prmB gene in A. brasilense resulted in an increased sensitivity to chloramphenicol and resistance to tiamulin and clindamycin, which are known to bind at the peptidyl transferase center (PTC) in the ribosome. These observations suggested that the inability of prmB:km mutant to methylate L3 protein might alter hydrophobicity in the antibiotic-binding pocket of the PTC, which might affect the binding of chloramphenicol, clindamycin, and tiamulin differentially. This is the first report showing the role of PrmB-type N5-glutamine methyltransferases in conferring resistance to tiamulin and clindamycin in any bacterium. PMID:24573606

  11. Draft Genome Sequence of Anaeromyxobacter sp. Strain PSR-1, an Arsenate-Respiring Bacterium Isolated from Arsenic-Contaminated Soil

    OpenAIRE

    Tonomura, Mimori; Ehara, Ayaka; Suzuki, Haruo; Amachi, Seigo

    2015-01-01

    Here, we report a draft genome sequence of Anaeromyxobacter sp. strain PSR-1, an arsenate-respiring bacterium isolated from arsenic-contaminated soil. It contained three distinct arsenic resistance gene clusters (ars operons), while no respiratory arsenate reductase gene (arr) was identified.

  12. Crystallization and preliminary crystallographic characterization of LmACR2, an arsenate/antimonate reductase from Leishmania major

    OpenAIRE

    Bisacchi, Davide; Zhou, Yao; Rosen, Barry P.; Mukhopadhyay, Rita; Bordo, Domenico

    2006-01-01

    LmACR2 from L. major is the first rhodanese-like enzyme directly involved in the reduction of arsenate and antimonate to be crystallized. Diffraction data have been collected to 1.99 Å resolution using synchrotron X-rays.

  13. Crystallization and preliminary crystallographic characterization of LmACR2, an arsenate/antimonate reductase from Leishmania major

    Energy Technology Data Exchange (ETDEWEB)

    Bisacchi, Davide [Bioinformatics and Structural Proteomics, IST-National Cancer Research Institute, Genova (Italy); Zhou, Yao; Rosen, Barry P.; Mukhopadhyay, Rita [Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, Michigan (United States); Bordo, Domenico, E-mail: domenico.bordo@istge.it [Bioinformatics and Structural Proteomics, IST-National Cancer Research Institute, Genova (Italy)

    2006-10-01

    LmACR2 from L. major is the first rhodanese-like enzyme directly involved in the reduction of arsenate and antimonate to be crystallized. Diffraction data have been collected to 1.99 Å resolution using synchrotron X-rays. Arsenic is present in the biosphere owing either to the presence of pesticides and herbicides used in agricultural and industrial activities or to leaching from geological formations. The health effects of prolonged exposure to arsenic can be devastating and may lead to various forms of cancer. Antimony(V), which is chemically very similar to arsenic, is used instead in the treatment of leishmaniasis, an infection caused by the protozoan parasite Leishmania sp.; the reduction of pentavalent antimony contained in the drug Pentostam to the active trivalent form arises from the presence in the Leishmania genome of a gene, LmACR2, coding for the protein LmACR2 (14.5 kDa, 127 amino acids) that displays weak but significant sequence similarity to the catalytic domain of Cdc25 phosphatase and to rhodanese enzymes. For structural characterization, LmACR2 was overexpressed, purified to homogeneity and crystallized in a trigonal space group (P321 or P3{sub 1}21/P3{sub 2}21). The protein crystallized in two distinct trigonal crystal forms, with unit-cell parameters a = b = 111.0, c = 86.1 Å and a = b = 111.0, c = 175.6 Å, respectively. At a synchrotron beamline, the diffraction pattern extended to a resolution limit of 1.99 Å.

  14. Crystallization and preliminary crystallographic characterization of LmACR2, an arsenate/antimonate reductase from Leishmania major

    International Nuclear Information System (INIS)

    LmACR2 from L. major is the first rhodanese-like enzyme directly involved in the reduction of arsenate and antimonate to be crystallized. Diffraction data have been collected to 1.99 Å resolution using synchrotron X-rays. Arsenic is present in the biosphere owing either to the presence of pesticides and herbicides used in agricultural and industrial activities or to leaching from geological formations. The health effects of prolonged exposure to arsenic can be devastating and may lead to various forms of cancer. Antimony(V), which is chemically very similar to arsenic, is used instead in the treatment of leishmaniasis, an infection caused by the protozoan parasite Leishmania sp.; the reduction of pentavalent antimony contained in the drug Pentostam to the active trivalent form arises from the presence in the Leishmania genome of a gene, LmACR2, coding for the protein LmACR2 (14.5 kDa, 127 amino acids) that displays weak but significant sequence similarity to the catalytic domain of Cdc25 phosphatase and to rhodanese enzymes. For structural characterization, LmACR2 was overexpressed, purified to homogeneity and crystallized in a trigonal space group (P321 or P3121/P3221). The protein crystallized in two distinct trigonal crystal forms, with unit-cell parameters a = b = 111.0, c = 86.1 Å and a = b = 111.0, c = 175.6 Å, respectively. At a synchrotron beamline, the diffraction pattern extended to a resolution limit of 1.99 Å

  15. Respiratory detoxification of nitric oxide by the cytochrome c nitrite reductase of Escherichia coli.

    Science.gov (United States)

    Poock, Susannah R; Leach, Emily R; Moir, James W B; Cole, Jeffrey A; Richardson, David J

    2002-06-28

    Nitric oxide is a key element in host defense against invasive pathogens. The periplasmic cytochrome c nitrite reductase (NrfA) of Escherichia coli catalyzes the respiratory reduction of nitrite, but in vitro studies have shown that it can also reduce nitric oxide. The physiological significance of the latter reaction in vivo has never been assessed. In this study the reduction of nitric oxide by Escherichia coli was measured in strains active or deficient in periplasmic nitrite reduction. Nrf(+) cells, harvested from cultures grown anaerobically, possessed a nitric-oxide reductase activity with physiological electron donation of 60 nmol min(-1) x mg dry wt(-1), and an in vivo turnover number of NrfA of 390 NO* s(-1) was calculated. Nitric-oxide reductase activity could not be detected in Nrf(-) strains. Comparison of the anaerobic growth of Nrf(+) and Nrf(-) strains revealed a higher sensitivity to nitric oxide in the NrfA(-) strains. A higher sensitivity to the nitrosating agent S-nitroso-N-acetyl penicillamine (SNAP) was also observed in agar plate disk-diffusion assays. Oxygen respiration by E. coli was also more sensitive to nitric oxide in the Nrf(-) strains compared with the Nrf(+) parent strain. The results demonstrate that active periplasmic cytochrome c nitrite reductase can confer the capacity for nitric oxide reduction and detoxification on E. coli. Genomic analysis of many pathogenic enteric bacteria reveals the presence of nrf genes. The present study raises the possibility that this reflects an important role for the cytochrome c nitrite reductase in nitric oxide management in oxygen-limited environments. PMID:11960983

  16. The general mitochondrial processing peptidase from potato is an integral part of cytochrome c reductase of the respiratory chain.

    OpenAIRE

    Braun, H P; Emmermann, M; Kruft, V; Schmitz, U K

    1992-01-01

    The major mitochondrial processing activity removing presequences from nuclear encoded precursor proteins is present in the soluble fraction of fungal and mammalian mitochondria. We found that in potato, this activity resides in the inner mitochondrial membrane. Surprisingly, the proteolytic activity co-purifies with cytochrome c reductase, a protein complex of the respiratory chain. The purified complex is bifunctional, as it has the ability to transfer electrons from ubiquinol to cytochrome...

  17. "Artifactual" arsenate DNA

    DEFF Research Database (Denmark)

    Nielsen, Peter E

    2012-01-01

    The recent claim by Wolfe-Simon et al. that the Halomonas bacterial strain GFAJ-1 when grown in arsenate-containing medium with limiting phosphate is able to substitute phosphate with arsenate in biomolecules including nucleic acids and in particular DNA(1) arose much skepticism, primarily due...... to the very limited chemical stability of arsenate esters (see ref. 2 and references therein). A major part of the criticisms was concerned with the insufficient (bio)chemical evidence in the Wolfe-Simon study for the actual chemical incorporation of arsenate in DNA (and/or RNA). Redfield et al. now present...... evidence that the identification of arsenate DNA was artifactual....

  18. Natural Arsenate DNA?

    DEFF Research Database (Denmark)

    Nielsen, Peter E

    2011-01-01

    The recent paper by Wolfe-Simon et al.1 reporting a bacterial strain, which is able to grow in high concentrations of arsenate, apparently in the absence of phosphate, and claims that in this strain arsenate is substituting for phosphate, e.g. in nucleic acids (Figure 1), was highly profiled, att...

  19. Urocanate reductase: identification of a novel anaerobic respiratory pathway in Shewanella oneidensis MR-1.

    Science.gov (United States)

    Bogachev, Alexander V; Bertsova, Yulia V; Bloch, Dmitry A; Verkhovsky, Michael I

    2012-12-01

    Interpretation of the constantly expanding body of genomic information requires that the function of each gene be established. Here we report the genomic analysis and structural modelling of a previously uncharacterized redox-metabolism protein UrdA (SO_4620) of Shewanella oneidensis MR-1, which led to a discovery of the novel enzymatic activity, urocanate reductase. Further cloning and expression of urdA, as well as purification and biochemical study of the gene's product UrdA and redox titration of its prosthetic groups confirmed that the latter is indeed a flavin-containing enzyme catalysing the unidirectional reaction of two-electron reduction of urocanic acid to deamino-histidine, an activity not reported earlier. UrdA exhibits both high substrate affinity and high turnover rate (K(m)  Clostridium, the latter including the human pathogen Clostridium tetani. The UrdA activity in S. oneidensis is induced by its substrate under anaerobic conditions and it enables anaerobic growth with urocanic acid as a sole terminal electron acceptor. The latter capability can provide the cells of UrdA-containing bacteria with a niche where no other bacteria can compete and survive. PMID:23078170

  20. “Artifactual” arsenate DNA

    OpenAIRE

    Nielsen, Peter E.

    2012-01-01

    The recent claim by Wolfe-Simon et al. that the Halomonas bacterial strain GFAJ-1 when grown in arsenate-containing medium with limiting phosphate is able to substitute phosphate with arsenate in biomolecules including nucleic acids and in particular DNA 1 arose much skepticism, primarily due to the very limited chemical stability of arsenate esters (see ref. 2 and references therein). A major part of the criticisms was concerned with the insufficient (bio)chemical evidence in the Wolfe-Simon...

  1. Regulation of Escherichia coli fumarate reductase (frdABCD) operon expression by respiratory electron acceptors and the fnr gene product.

    OpenAIRE

    Jones, H. M.; Gunsalus, R P

    1987-01-01

    The fumarate reductase enzyme complex, encoded by the frdABCD operon, allows Escherichia coli to utilize fumarate as a terminal electron acceptor for anaerobic oxidative phosphorylation. To analyze the expression of fumarate reductase, protein and operon fusions were constructed between the frdA and the lacZ genes and introduced onto the E. coli chromosome at the lambda attachment site. Expression of beta-galactosidase from either fusion was increased 10-fold during anaerobic versus aerobic c...

  2. Substrate-dependent modulation of the enzymatic catalytic activity: reduction of nitrate, chlorate and perchlorate by respiratory nitrate reductase from Marinobacter hydrocarbonoclasticus 617.

    Science.gov (United States)

    Marangon, Jacopo; Paes de Sousa, Patrícia M; Moura, Isabel; Brondino, Carlos D; Moura, José J G; González, Pablo J

    2012-07-01

    The respiratory nitrate reductase complex (NarGHI) from Marinobacter hydrocarbonoclasticus 617 (Mh, formerly Pseudomonas nautica 617) catalyzes the reduction of nitrate to nitrite. This reaction is the first step of the denitrification pathway and is coupled to the quinone pool oxidation and proton translocation to the periplasm, which generates the proton motive force needed for ATP synthesis. The Mh NarGH water-soluble heterodimer has been purified and the kinetic and redox properties have been studied through in-solution enzyme kinetics, protein film voltammetry and spectropotentiometric redox titration. The kinetic parameters of Mh NarGH toward substrates and inhibitors are consistent with those reported for other respiratory nitrate reductases. Protein film voltammetry showed that at least two catalytically distinct forms of the enzyme, which depend on the applied potential, are responsible for substrate reduction. These two forms are affected differentially by the oxidizing substrate, as well as by pH and inhibitors. A new model for the potential dependence of the catalytic efficiency of Nars is proposed. PMID:22561116

  3. ArxA, a new clade of arsenite oxidase within the DMSO reductase family of molybdenum oxidoreductases

    Science.gov (United States)

    Zargar, Kamrun; Conrad, Alison; Bernick, David L.; Lowe, Todd M.; Stolc, Viktor; Hoeft, Shelley; Oremland, Ronald S.; Stolz, John; Saltikov, Chad W.

    2012-01-01

    Arsenotrophy, growth coupled to autotrophic arsenite oxidation or arsenate respiratory reduction, occurs only in the prokaryotic domain of life. The enzymes responsible for arsenotrophy belong to distinct clades within the DMSO reductase family of molybdenum-containing oxidoreductases: specifically arsenate respiratory reductase, ArrA, and arsenite oxidase, AioA (formerly referred to as AroA and AoxB). A new arsenite oxidase clade, ArxA, represented by the haloalkaliphilic bacterium Alkalilimnicola ehrlichii strain MLHE-1 was also identified in the photosynthetic purple sulfur bacterium Ectothiorhodospira sp. strain PHS-1. A draft genome sequence of PHS-1 was completed and an arx operon similar to MLHE-1 was identified. Gene expression studies showed that arxA was strongly induced with arsenite. Microbial ecology investigation led to the identification of additional arxA-like sequences in Mono Lake and Hot Creek sediments, both arsenic-rich environments in California. Phylogenetic analyses placed these sequences as distinct members of the ArxA clade of arsenite oxidases. ArxA-like sequences were also identified in metagenome sequences of several alkaline microbial mat environments of Yellowstone National Park hot springs. These results suggest that ArxA-type arsenite oxidases appear to be widely distributed in the environment presenting an opportunity for further investigations of the contribution of Arx-dependent arsenotrophy to the arsenic biogeochemical cycle.

  4. Embryotoxicity of arsenite and arsenate

    International Nuclear Information System (INIS)

    The distribution of 74As-labelled and arsenite in pregnant mice and a monkey has been studied by autoradiography and gamma counting of isolated tissues, and their in vitro toxicity to a chondrogenic system has been investigated. With both arsenic forms, given as single intravenous injections to the mother, the 74As-arsenic appeared to pass the mouse placenta relatively freely and approximately to the same extent. The retention time in material tissues including the placenta was, however, around three times longer with arsenite than with arsenate. In early gestation, high activity was registered in the embryonic neuroepithelium, which correlates well with reported CNS malformations in rodents. In late gestation, the distribution pattern was more like that in the adults. Accumulation in skin and squamous epithelia of the upper gastrointestinal tract (oral cavity, oesophagus and oesophageal region of stomach) dominated the distribution pucture, especially at a long survival interval. Arsenate, but not arsenite, showed affinity for the calcified areas of the skeleton. A marmoset monkey in late gestation receiving arsenite showed a somewhat lower rate of placental transfer than the mice. Skin and liver had the highest concentrations (at 8 hrs), both in mother and foetuses. This species is known not to methylate arsenic, resulting in stronger binding and longer retention times of arsenic as compared with other species. The stronger binding in maternal tissues may possibly explain the lower rate of placental transfer. Arsenite was shown to inhibit cartilage formation in a chick limb bud mesenchymal spot culture system (ED50 approximately 5-10μM) while arsenate seemed to be without effect at concentrations up to 200 μM (highest tested). Arsenate, however, showed a potential of the arsenite toxicity. (author)

  5. Absence of detectable arsenate in DNA from arsenate-grown GFAJ-1 cells

    OpenAIRE

    Reaves, Marshall Louis; Sinha, Sunita; Rabinowitz, Joshua D.; Kruglyak, Leonid; Redfield, Rosemary J.

    2012-01-01

    A strain of Halomonas bacteria, GFAJ-1, has been reported to be able to use arsenate as a nutrient when phosphate is limiting, and to specifically incorporate arsenic into its DNA in place of phosphorus. However, we have found that arsenate does not contribute to growth of GFAJ-1 when phosphate is limiting and that DNA purified from cells grown with limiting phosphate and abundant arsenate does not exhibit the spontaneous hydrolysis expected of arsenate ester bonds. Furthermore, mass spectrom...

  6. Arsenate uncoupling of oxidative phosphorylation in isolated plant mitochondria

    Energy Technology Data Exchange (ETDEWEB)

    Wickes, W.A.; Wiskich, J.T.

    1976-01-01

    The uncoupling by arsenate of beetroot and cauliflower bud mitochondria showed the following characteristics: arsenate stimulation of respiration above the rate found with phosphate; inhibition of arsenate-stimulated respiration by phosphate; enhancement of arsenate-stimulated respiration by ADP; only partial prevention of this ADP-enhanced respiration by atractyloside; inhibition by oligomycin of the arsenate-stimulated respiration back to the phosphate rate; and the absence of any stimulatory effect of ADP in the presence of oligomycin. These results are qualitatively analogous to those reported for arsenate uncoupling in rat liver mitochondria. Arsenate stimulated malate oxidation, presumably by stimulating malate entry, in both beetroot and cauliflower bud mitochondria; however, high rates of oxidation, and presumably entry, were only sustained with arsenate in beetroot mitochondria. NADH was oxidized rapidly in cauliflower bud mitochondria in the presence of arsenate, showing that arsenate did not inhibit electron transfer processes.

  7. Thermochemical investigations on uranyl phosphates and arsenates

    International Nuclear Information System (INIS)

    The results are described of a study of the thermochemical stability of anhydrous uranyl phosphates and arsenates. A number of aspects of chemical technological importance are indicated in detail. The synthesized anhydrous uranyl phosphates and arsenates were very hygroscopic, so that experiments on these compounds had to be carried out under moisture-free conditions. Further characterisation of these compounds are given, including a study of their thermal stabilities and phase relations. The uranyl phosphates reduced reversibly at temperatures of the order of 1100 to 16000C. This makes it possible to express their relative stabilities quantitatively, in terms of the oxygen pressures of the reduction reactions. The thermal decomposition of uranyl arsenates did not occur by reduction, as for the phosphates, but by giving off arsenic oxide vapour. The results of measurements of enthalpies of solution led to the determination of the enthalpies of formation, heat capacity and the standard entropies of the uranyl arsenates. The thermochemical functions at high-temperatures could consequently be calculated. Attention is paid to the possible formation of uranium arsenates, whose uranium has a valency lower than six, hitherto not reported in literature. It was not possible to prepare arsenates of tetravalent uranium. However, three new compounds were observed, one of these, UAsO5, was studied in some detail. (Auth.)

  8. Dissolution of Arsenic Minerals Mediated by Dissimilatory Arsenate Reducing Bacteria: Estimation of the Physiological Potential for Arsenic Mobilization

    Directory of Open Access Journals (Sweden)

    Drewniak Lukasz

    2014-01-01

    Full Text Available The aim of this study was characterization of the isolated dissimilatory arsenate reducing bacteria in the context of their potential for arsenic removal from primary arsenic minerals through reductive dissolution. Four strains, Shewanella sp. OM1, Pseudomonas sp. OM2, Aeromonas sp. OM4, and Serratia sp. OM17, capable of anaerobic growth with As (V reduction, were isolated from microbial mats from an ancient gold mine. All of the isolated strains: (i produced siderophores that promote dissolution of minerals, (ii were resistant to dissolved arsenic compounds, (iii were able to use the dissolved arsenates as the terminal electron acceptor, and (iii were able to use copper minerals containing arsenic minerals (e.g., enargite as a respiratory substrate. Based on the results obtained in this study, we postulate that arsenic can be released from some As-bearing polymetallic minerals (such as copper ore concentrates or middlings under reductive conditions by dissimilatory arsenate reducers in indirect processes.

  9. Thermochemical investigations on uranyl phosphates and arsenates

    International Nuclear Information System (INIS)

    Results are described of a study of the thermochemical stability of anhydrous phosphates and arsenates. The results of phase studies deal with compound formation and characterization, coexisting phases and limiting physical or chemical properties. The uranyl phosphates evolve oxygen at higher temperatures and the arsenates lose arsenic oxide vapour. These phenomena give the possibility to describe their thermodynamic stabilities. Thus oxygen pressures of uranyl phosphates have been measured using a static, non-isothermal method. Having made available the pure anhydrous compounds in the course of this investigation, molar thermodynamic quantities have been measured as well. These include standard enthalpies of formation from solution calorimetry and high-temperature heat-capacity functions derived from enthalpy increments measured. Some attention is given to compounds with uranium in valencies lower than six which have been met during the investigation. An evaluation is made of the thermodynamics of the compounds studied, to result in tabulized high-temperature thermodynamic functions. Relative stabilities within the systems are discussed and comparisons of the uranyl phosphates and the arsenates are made. (Auth.)

  10. Crystal structure of the YffB protein from Pseudomonas aeruginosa suggests a glutathione-dependent thiol reductase function

    Directory of Open Access Journals (Sweden)

    Dauter Zbigniew

    2004-03-01

    Full Text Available Abstract Background The yffB (PA3664 gene of Pseudomonas aeruginosa encodes an uncharacterized protein of 13 kDa molecular weight with a marginal sequence similarity to arsenate reductase from Escherichia coli. The crystal structure determination of YffB was undertaken as part of a structural genomics effort in order to assist with the functional assignment of the protein. Results The structure was determined at 1.0 Å resolution by single-wavelength anomalous diffraction. The fold is very similar to that of arsenate reductase, which is an extension of the thioredoxin fold. Conclusion Given the conservation of the functionally important residues and the ability to bind glutathione, YffB is likely to function as a GSH-dependent thiol reductase.

  11. Investigation of biochemical responses of Bacopa monnieri L. upon exposure to arsenate.

    Science.gov (United States)

    Mishra, Seema; Srivastava, Sudhakar; Dwivedi, Sanjay; Tripathi, Rudra Deo

    2013-08-01

    Widespread contamination of arsenic (As) is recognized as a global problem due to its well-known accumulation by edible and medicinal plants and associated health risks for the humans. In this study, phytotoxicity imposed upon exposure to arsenate [As(V); 0-250 μM for 1-7 days] and ensuing biochemical responses were investigated in a medicinal herb Bacopa monnieri L. vis-à-vis As accumulation. Plants accumulated substantial amount of As (total 768 μg g(-1) dw at 250 μM As(V) after 7 days) with the maximum As retention being in roots (60%) followed by stem (23%) and leaves (17%). The level of cysteine and total nonprotein thiols (NP-SH) increased significantly at all exposure concentrations and durations. Besides, the level of metalloid binding ligands viz., glutathione (GSH) and phytochelatins (PCs) increased significantly at the studied concentrations [50 and 250 μM As(V)] in both roots and leaves. The activities of various enzymes viz., arsenate reductase (AR), glutathione reductase (GR), superoxide dismutase (SOD), guaiacol peroxidase (GPX), ascorbate peroxidase (APX), and catalase (CAT) showed differential but coordinated stimulation in leaves and roots to help plants combat As toxicity up to moderate exposure concentrations (50 μM). However, beyond 50 μM, biomass production was found to decrease along with photosynthetic pigments and total soluble proteins, whereas lipid peroxidation increased. In conclusion, As accumulation potential of Bacopa may warrant its use as a phytoremediator but if Bacopa growing in contaminated areas is consumed by humans, it may prove to be toxic for health. PMID:21656644

  12. Phosphate transport and arsenate resistance in the cyanobacterium Anabaena variabilis.

    OpenAIRE

    Thiel, T.

    1988-01-01

    Cells of the cyanobacterium Anabaena variabilis starved for phosphate for 3 days took up phosphate at about 100 times the rate of unstarved cells. Kinetic data suggested that a new transport system had been induced by starvation for phosphate. The inducible phosphate transport system was quickly repressed by addition of Pi. Phosphate-starved cells were more sensitive to the toxic effects of arsenate than were unstarved cells, but phosphate could alleviate some of the toxicity. Arsenate was a ...

  13. Effect of Competing Anions on Arsenate Adsorption onto Maghemite Nanoparticles

    Institute of Scientific and Technical Information of China (English)

    T. Tuutijarvi; E. Repo; R. Vahala; M. Sillanpaa; G. Chen

    2012-01-01

    This paper reports the effect of several competing anions on arsenate adsorption with maghemite nanoparticles. Sulphate (as SO4), nitrate (as NO3-N), phosphate (as PO4-P) ions and silicate-(as SiO2) were-studied in dual solution with arsenate. Moreover, the combined effect of ions and other water characteristics were examined with a natural groundwater sample which was spiked with a certain amount of arsenate. Arsenate batch adsorption experiments were carried out with two different kinds of maghemite-a commercially, available one and a homemade one using the sol-gel orocess. Sulohate (≤250 mg.L-1) and nitrate (≤ 12 mg.L-1) had a neglivible effect onthe arsenate (0.5 mg.L-1) adsorption at pH 3. However, both phosphate (42.9 mg·L-1) and silicate (450 mg.L-j) had an adverse impact on arsenate (43 mg.L-1) adsorption at pH 7. Phosphate (41.5 mg.L-1) showed minimal competition with arsenate (0.5 mg.L-1), while silicate (410 mg.L-1) inhibition was insignificant for all studied As(V) concentrations at p.H 3. The removal of arsenate from the groundwater sample was as efficient as from labo-ratory water tor 0.3 mgL -1 AS(V) botll at pH3 and pH7.

  14. Arsenic-Lipid Complex Formation During the Active Transport of Arsenate in Yeast

    Science.gov (United States)

    Cerbón, Jorge

    1969-01-01

    In studying formation of an arsenic-lipid complex during the active transport of 74As-arsenate in yeast, it was found that adaptation of yeast to arsenate resulted in cell populations which showed a deficient inflow of arsenate as compared to the nonadapted yeast. Experiments with both types of cells showed a direct correlation between the arsenate taken up and the amount of As-lipid complex formed. 74As-arsenate was bound exclusively to the phosphoinositide fraction of the cellular lipids. When arsenate transport was inhibited by dinitrophenol and sodium azide, the formation of the As-lipid complex was also inhibited. Phosphate did not interfere with the arsenate transport at a non-inhibitory concentration of external arsenate (10−9m). The As-adapted cells but not the unadapted cells were able to take up phosphate when growing in the presence of 10−2m arsenate. PMID:5773018

  15. Arsenic-lipid complex formatinon during the active transport of arsenate in yeast.

    Science.gov (United States)

    Cerbón, J

    1969-02-01

    In studying formation of an arsenic-lipid complex during the active transport of (74)As-arsenate in yeast, it was found that adaptation of yeast to arsenate resulted in cell populations which showed a deficient inflow of arsenate as compared to the nonadapted yeast. Experiments with both types of cells showed a direct correlation between the arsenate taken up and the amount of As-lipid complex formed. (74)As-arsenate was bound exclusively to the phosphoinositide fraction of the cellular lipids. When arsenate transport was inhibited by dinitrophenol and sodium azide, the formation of the As-lipid complex was also inhibited. Phosphate did not interfere with the arsenate transport at a non-inhibitory concentration of external arsenate (10(-9)m). The As-adapted cells but not the unadapted cells were able to take up phosphate when growing in the presence of 10(-2)m arsenate. PMID:5773018

  16. Physico-Chemical Studies on the Consumption of Copper Arsenate: Thermometric Studies on the Composition of Cupric Arsenate

    Directory of Open Access Journals (Sweden)

    M. S. Bhadraver

    1962-10-01

    Full Text Available The formation and composition of cupric arsenate complexes has been studied by the thermometric measurements involving thermometric titrations between CuSO45H2O and disodium hydrogen-arsenate at several concentration of the reactants both by direct and reverse methods.In the direct method thermometric titration curves suggest the formation of CuHAsO4 greenish blue ppt. whereas in the reverse titration the formation of CuHAsO4 is supported.

  17. Expression profiling of Crambe abyssinica under arsenate stress identifies genes and gene networks involved in arsenic metabolism and detoxification

    Directory of Open Access Journals (Sweden)

    Kandasamy Suganthi

    2010-06-01

    Full Text Available Abstract Background Arsenic contamination is widespread throughout the world and this toxic metalloid is known to cause cancers of organs such as liver, kidney, skin, and lung in human. In spite of a recent surge in arsenic related studies, we are still far from a comprehensive understanding of arsenic uptake, detoxification, and sequestration in plants. Crambe abyssinica, commonly known as 'abyssinian mustard', is a non-food, high biomass oil seed crop that is naturally tolerant to heavy metals. Moreover, it accumulates significantly higher levels of arsenic as compared to other species of the Brassicaceae family. Thus, C. abyssinica has great potential to be utilized as an ideal inedible crop for phytoremediation of heavy metals and metalloids. However, the mechanism of arsenic metabolism in higher plants, including C. abyssinica, remains elusive. Results To identify the differentially expressed transcripts and the pathways involved in arsenic metabolism and detoxification, C. abyssinica plants were subjected to arsenate stress and a PCR-Select Suppression Subtraction Hybridization (SSH approach was employed. A total of 105 differentially expressed subtracted cDNAs were sequenced which were found to represent 38 genes. Those genes encode proteins functioning as antioxidants, metal transporters, reductases, enzymes involved in the protein degradation pathway, and several novel uncharacterized proteins. The transcripts corresponding to the subtracted cDNAs showed strong upregulation by arsenate stress as confirmed by the semi-quantitative RT-PCR. Conclusions Our study revealed novel insights into the plant defense mechanisms and the regulation of genes and gene networks in response to arsenate toxicity. The differential expression of transcripts encoding glutathione-S-transferases, antioxidants, sulfur metabolism, heat-shock proteins, metal transporters, and enzymes in the ubiquitination pathway of protein degradation as well as several unknown

  18. ECOTOXICOLOGICAL BIOASSAYS OF THE EARTHWORMS ALLOLOBOPHORA CALIGINOSA SAVIGNY AND PHERETIMA HAWAYANA ROSA TREATED WITH ARSENATE

    Directory of Open Access Journals (Sweden)

    Abdelmonem Mohamed Khalil

    2013-01-01

    Full Text Available Little research has been carried out on the effect of arsenate on earthworms. Ecotoxicological laboratory tests are fundamental tools for assessing the toxicity of arsenate to soil organisms. In this study, the impact of arsenate on the survival, reproduction and behaviour of the endogenic earthworms Allolobophora caliginosa and the anecic earthworms Pheretima hawayana has been quantified. The 96-h LC 50 of arsenate was estimated as 233.43 mg arsenate Kg-1 soil. d.w. for P. hawayana which is significantly higher than that of A. caliginosa 147.24±27.16 mg arsenate kg-1 soil d.w. The number of juveniles of P. hawayana was significantly higher than that of A. caliginosa at the arsenate concentrations 180, 240 and 400 mg kg-1 soil dry weight. With the exception of the control (6.5 mg arsenate kg-1 soil.d.w., P. hawayana showed an avoidance behaviour for soils treated with all tested concentrations. A. caliginosa preferred soils treated with 6.5, 60, 110, 180 mg arsenate kg-1 soil d.w., while the avoidance behaviour has been recorded only at 240 and 400 mg arsenate kg-1 soil. d.w. This means that A. caliginosa individuals feed less when exposed to arsenate. On the contrary, the P. hawayana worms could be escaped into their deep vertical burrows when exposed to arsenate.

  19. Sorption and desorption of arsenate and arsenite on calcite

    DEFF Research Database (Denmark)

    Sø, Helle Ugilt; Postma, Diederik Jan; Jakobsen, Rasmus;

    2008-01-01

    The adsorption and desorption of arsenate (As(V)) and arsenite (As(111)) oil calcite was investigated in a series of batch experiments in calcite-equilibrated solutions. The solutions covered a broad range of pH, alkalinity, calcium concentration and ionic strength. The initial arsenic concentrat......The adsorption and desorption of arsenate (As(V)) and arsenite (As(111)) oil calcite was investigated in a series of batch experiments in calcite-equilibrated solutions. The solutions covered a broad range of pH, alkalinity, calcium concentration and ionic strength. The initial arsenic...

  20. Arsenate Adsorption On Ruthenium Oxides: A Spectroscopic And Kinetic Investigation

    Science.gov (United States)

    Arsenate adsorption on amorphous (RuO2•1.1H2O) and crystalline (RuO2) ruthenium oxides was evaluated using spectroscopic and kinetic methods to elucidate the adsorption mechanism. Extended X-ray absorption fine structure spectroscopy (EXAFS) was ...

  1. Effect of lead arsenate in soil on vegetables

    Energy Technology Data Exchange (ETDEWEB)

    Fleming, W.E.; Baker, F.E.; Koblitsky, L.

    1943-04-01

    Experiments were performed to determine what effects lead arsenate added to soils had on the germination, growth, and yield of garden vegetables. The vegetables used were asparagus, broccoli, brussels sprouts, cabbage, carrots, cauliflower, corn, popcorn, pepper, cucumber, eggplant, endive, kohlrabi, lettuce, okra, onion, parsley, parsnip, pea, pumpkin, radish, squash, tomato, turnip, watermelon, beets, muskmelon, spinach, lima beans, and string beans.

  2. Mechanism of arsenate inhibition of the glucose active transport system in Neurospora crassa

    International Nuclear Information System (INIS)

    The mechanism of arsenate inhibition of the glucose active transport system in wild-type cells of Neurospora crassa has been examined. Arsenate treatment results in approximately 65% inhibition of the glucose active transport system with only a small depression of cellular ATP levels. The transport system is not inhibited in cells treated with sodium arsenate in the presence of sodium azide. The transport inhibition is suppressed when orthophosphate is present during arsenate treatment, but is not reversed by orthophosphate when added after the arsenate treatment. The transport inhibition is completely reversed by treatment of the cells with mercaptoethanol. Gel chromatography of sonicates of intact cells which had been treated with [74As]arsenate reveals three radioactive peaks, one with the elution volume of arsenate, one with the elution volume of arsenite, and in high molecular-weight radioactive fraction. Treatment of the high molecular-weight radioactive fraction with mercaptoethanol results in the production of radioactive arsenite. In view of these findings, it is proposed that arsenate inhibition of the glucose active transport system in Neurospora involves transport of arsenate into the cells, probably via the orthophosphate transport system, reduction of the transported arsenate to arsenite, and interaction of arsenite with some component of the glucose active transport system, presumably via covalent binding with vicinal thiol groups. 15 references, 4 figures, 2 tables

  3. Respiratory System

    Science.gov (United States)

    ... page from the NHLBI on Twitter. The Respiratory System The respiratory system is made up of organs ... and the muscles that enable breathing. The Respiratory System Figure A shows the location of the respiratory ...

  4. Arsenate removal from aqueous solutions using modified red mud

    International Nuclear Information System (INIS)

    Red mud (RM), a waste tailing from alumina production, was modified with FeCl3 for the removal of arsenate from water. The RM and modified red mud (MRM) were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD) microanalysis. Adsorption of arsenate on modified red mud (MRM) was studied as a function of time, pH, and coexisting ions. Equilibrium time for arsenate removal was 24 h. Solution pH significantly affected the adsorption, and the adsorption capacity increased with the decrease in pH. Langmuir and Freundlich isotherms equation were used to fit the adsorption isotherms. The Langmuir isotherm was the best-fit adsorption isotherm model for the experimental data. Adsorption capacity of MRM was found to be 68.5 mg/g, 50.6 mg/g and 23.2 mg/g at pH 6, 7 and 9, respectively. NO3- had little effect on the adsorption. Ca2+ enhanced the adsorption, while HCO3- decreased the adsorption. MRM could be regenerated with NaOH, and the regeneration efficiency reached 92.1% when the concentration of NaOH was 0.2 mol/L

  5. X-ray graphical and thermodynamical study of mercury arsenates

    International Nuclear Information System (INIS)

    Purposes of the work are both determination of lattice parameters on the base of X-ray graphical data and experimental study of thermal conduction dependence of mercury arsenates Hg(AsO3)2 and Hg3(AsO4)2. In this work for the first time the parameters of elementary cell thermal conduction in the range 298.15-625 K were determined. Formation of equilibrium contents of mercury arsenates was confirmed by X-ray phase analysis conducted on DRON-2,0 unit under Cu K - radiation. Curves of thermal-differential analysis show, that Hg(AsO3)2 and Hg3(AsO4)2 melting incongruently, relatively at 725 and 790 grad C. Displaying of X-ray- grammars of examined compounds have been conducted by homology method. On the base the displaying parameter of lattice crystallization were determined. Further arsenates were exposed to calorimetric research for determination of its thermal conduction. It is shown, that Hg3(AsO4)2 thermal conduction has maximum at 448 K and then it value is go down at 473 K and then smoothly increasing. It was supposed, such behavior is related with second kind phase transformation

  6. Possible Roles of Plant Sulfurtransferases in Detoxification of Cyanide, Reactive Oxygen Species, Selected Heavy Metals and Arsenate

    Directory of Open Access Journals (Sweden)

    Parvin Most

    2015-01-01

    Full Text Available Plants and animals have evolved various potential mechanisms to surmount the adverse effects of heavy metal toxicity. Plants possess low molecular weight compounds containing sulfhydryl groups (-SH that actively react with toxic metals. For instance, glutathione (γ-Glu-Cys-Gly is a sulfur-containing tripeptide thiol and a substrate of cysteine-rich phytochelatins (γ-Glu-Cys2–11-Gly (PCs. Phytochelatins react with heavy metal ions by glutathione S-transferase in the cytosol and afterwards they are sequestered into the vacuole for degradation. Furthermore, heavy metals induce reactive oxygen species (ROS, which directly or indirectly influence metabolic processes. Reduced glutathione (GSH attributes as an antioxidant and participates to control ROS during stress. Maintenance of the GSH/GSSG ratio is important for cellular redox balance, which is crucial for the survival of the plants. In this context, sulfurtransferases (Str, also called rhodaneses, comprise a group of enzymes widely distributed in all phyla, paving the way for the transfer of a sulfur atom from suitable sulfur donors to nucleophilic sulfur acceptors, at least in vitro. The best characterized in vitro reaction is the transfer of a sulfane sulfur atom from thiosulfate to cyanide, leading to the formation of sulfite and thiocyanate. Plants as well as other organisms have multi-protein families (MPF of Str. Despite the presence of Str activities in many living organisms, their physiological role has not been clarified unambiguously. In mammals, these proteins are involved in the elimination of cyanide released from cyanogenic compounds. However, their ubiquity suggests additional physiological functions. Furthermore, it is speculated that a member of the Str family acts as arsenate reductase (AR and is involved in arsenate detoxification. In summary, the role of Str in detoxification processes is still not well understood but seems to be a major function in the organism.

  7. Solubility and stability of barium arsenate and barium hydrogen arsenate at 25oC

    International Nuclear Information System (INIS)

    The inconsistency among current thermodynamic data of Ba3(AsO4)2(c) and BaHAsO4.H2O(c) led the authors to obtain independent solubility data of barium arsenate by both precipitation and dissolution experiments. Low and neutral pH (3.63-7.43) favored the formation of BaHAsO4.H2O(c). Both BaHAsO4.H2O(c) and Ba3(AsO4)2(c) formed at the neutral pH conditions (7.47, 7.66), whereas Ba3(AsO4)2(c) was the only solid phase precipitated at high pH (13.03, 13.10). The Ba3(AsO4)2(c) precipitate acquired at 50oC appeared as small leafy crystal, while the Ba3(AsO4)2(c) solid precipitated at 25oC comprised granular aggregate with some smaller crystal clusters. XRD and SEM analyses of Ba3(AsO4)2(c) and BaHAsO4.H2O(c) indicated that the solids were indistinguishable before and after the dissolution experiments. In the present work, the solubility products (Ksp) for Ba3(AsO4)2(c) and BaHAsO4.H2O(c) were determined to be 10-23.53(10-23.01 to 10-24.00) and 10-5.60(10-5.23 to 10-5.89), respectively. ΔGfo for Ba3(AsO4)2(c) and BaHAsO4.H2O(c) were calculated to be -3113.40 and -1544.47kJ/mol, respectively. There was no difference between the solubility products of the leafy and the granular Ba3(AsO4)2(c) solids

  8. Arsenate-induced maternal glucose intolerance and neural tube defects in a mouse model

    International Nuclear Information System (INIS)

    Background: Epidemiological studies have linked environmental arsenic (As) exposure to increased type 2 diabetes risk. Periconceptional hyperglycemia is a significant risk factor for neural tube defects (NTDs), the second most common structural birth defect. A suspected teratogen, arsenic (As) induces NTDs in laboratory animals. Objectives: We investigated whether maternal glucose homeostasis disruption was responsible for arsenate-induced NTDs in a well-established dosing regimen used in studies of arsenic's teratogenicity in early neurodevelopment. Methods: We evaluated maternal intraperitoneal (IP) exposure to As 9.6 mg/kg (as sodium arsenate) in LM/Bc/Fnn mice for teratogenicity and disruption of maternal plasma glucose and insulin levels. Selected compounds (insulin pellet, sodium selenate (SS), N-acetyl cysteine (NAC), L-methionine (L-Met), N-tert-Butyl-α-phenylnitrone (PBN)) were investigated for their potential to mitigate arsenate's effects. Results: Arsenate caused significant glucose elevation during an IP glucose tolerance test (IPGTT). Insulin levels were not different between arsenate and control dams before (arsenate, 0.55 ng/dl; control, 0.48 ng/dl) or after glucose challenge (arsenate, 1.09 ng/dl; control, 0.81 ng/dl). HOMA-IR index was higher for arsenate (3.9) vs control (2.5) dams (p = 0.0260). Arsenate caused NTDs (100%, p < 0.0001). Insulin pellet and NAC were the most successful rescue agents, reducing NTD rates to 45% and 35%. Conclusions: IPGTT, insulin assay, and HOMA-IR results suggest a modest failure of glucose stimulated insulin secretion and insulin resistance characteristic of glucose intolerance. Insulin's success in preventing arsenate-induced NTDs provides evidence that these arsenate-induced NTDs are secondary to elevated maternal glucose. The NAC rescue, which did not restore maternal glucose or insulin levels, suggests oxidative disruption plays a role.

  9. Arsenic Recovery by Stinging Nettle From Lead-Arsenate Contaminated Orchard Soils

    Science.gov (United States)

    Soil contamination with arsenic (As) is common in orchards with a history of lead-arsenate pesticide application. This problem is prevalent in the U.S. Northeast where lead-arsenate foliar sprays were used to control codling moth (Cydia pomonella) in apple orchards. Arsenic is not easily biodegrad...

  10. Comparison of arsenate and cadmium toxicity in a freshwater amphipod (Gammarus pulex)

    International Nuclear Information System (INIS)

    Cadmium is largely documented on freshwater organisms while arsenic, especially arsenate, is rarely studied. The kinetic of the LC50s values for both metals was realized on Gammarus pulex. Physiological [i.e. metal concentration in body tissues, bioconcentration factor (BCF)] effects and behavioural responses (via pleopods beats) were investigated after 240-h exposure. Arsenate LC50 value was 100 fold higher than Cd-LC50 value after 240-h exposure, while concentrations in gammarids were similar for both metals at their respective LC50s. BCF decreased with increasing cadmium concentration while BCF remained stable with increasing arsenate concentration. Moreover, BCF was between 148 and 344 times lower for arsenate than cadmium. A significant hypoventilation was observed for cadmium concentrations exceeding or close to the 240h-LC50Cd, while gammarids hyperventilated for the lowest arsenate concentrations and hypoventilated for the highest arsenate concentrations. We discussed the relationships between potential action mechanisms of these two metals and observed results. - Highlights: ► First study of arsenate toxicity in a Crustacean gammarid. ► Specific toxicological and behavioural responses to AsV and Cd contamination. ► Each metal led to specific-action mechanisms. ► Different energetic reallocation could explain specific behavioural responses. - This study brings to light the potential relationship between toxicological effects and behavioural responses of G. pulex exposed at both Cadmium and Arsenate.

  11. Effect of arsenate As (V) on the biomarkers of Myriophyllum alterniflorum in oligotrophic and eutrophic conditions.

    Science.gov (United States)

    Krayem, M; Deluchat, V; Rabiet, M; Cleries, K; Lenain, J F; Saad, Z; Kazpard, V; Labrousse, P

    2016-03-01

    Alternate watermilfoil, Myriophyllum alterniflorum is an aquatic macrophyte found in the Limousin rivers (France) whose potential for biomonitoring of metal pollution has been demonstrated. The objective of the present study carried out in vitro was to identify biomarkers for an early detection of the pollution by a metalloid As (V) in eutrophic and oligotrophic conditions. A synthetic medium of similar composition to the waters of the River Vienne was prepared. The morphological development of watermilfoil was monitored for 30 days, with or without contamination by 100 μg L(-1) As (V). In addition, the mineralization of plants and the analysis of biomarkers (chlorophylls, photosynthetic and respiratory intensities …) were investigated after 21 days. Our results indicated that eutrophic medium, induced a decrease in chlorophyll pigments, in growth and an increase in H2O2 compared to the oligotrophic medium. While, the presence of As (V), led to a decrease in the osmotic potential, pigment content, photosynthesis and respiration rates and an inhibition of shoot branching of plants in both conditions. However, a significant increase in H2O2 content was noted in the eutrophic medium. Finally, As (V) was found to be more accumulated in roots than shoots in both conditions but was more accumulated in oligotrophic one. Therefore, we can conclude that the water trophic level modifies the response of M. alterniflorum in presence of arsenate. Thus, M. alterniflorum shows a great promise in water-quality biomonitoring. PMID:26766024

  12. Competitive adsorption of arsenate and phosphate onto calcite; experimental results and modeling with CCM and CD-MUSIC

    DEFF Research Database (Denmark)

    Sø, Helle Ugilt; Postma, Dieke; Jakobsen, Rasmus;

    2012-01-01

    adsorption of arsenate onto calcite is of minor importance in most groundwater aquifers, as phosphate is often present at concentration levels sufficient to significantly reduce arsenate adsorption. The CD-MUSIC model for calcite was used successfully to model adsorption of arsenate and phosphate separately...

  13. Leaching of chromated copper arsenate wood preservatives: a review.

    Science.gov (United States)

    Hingston, J A; Collins, C D; Murphy, R J; Lester, J N

    2001-01-01

    Recent studies have generated conflicting data regarding the bioaccumulation and toxicity of leachates from preservative-treated wood. Due to the scale of the wood preserving industry, timber treated with the most common preservative, chromated copper arsenate (CCA), may form a significant source of metals in the aquatic environment. The existing literature on leaching of CCA is reviewed, and the numerous factors affecting leaching rates, including pH, salinity, treatment and leaching test protocols are discussed. It is concluded from the literature that insufficient data exists regarding these effects to allow accurate quantification of leaching rates, and also highlights the need for standardised leaching protocols. PMID:11202715

  14. Internal electron transfer within mitochondrial succinate-cytochrome C reductase

    International Nuclear Information System (INIS)

    Internal electron transfer within succinate-cytochrome C reductase from pigeon breast muscle mitochondria was followed by the pulse radiolytic technique. The electron equivalent is transferred from an unknown donor to b type cytochrome(s), in a first order process with a rate constant of: 660 +- 150s-1. This process might be the rate determining step of electron transfer in mitochondria, since it is similar in rate to the turnover number of the mitochondrial respiratory chain

  15. Comparative Proteomic Analysis of Rice Shoots Exposed to High Arsenate

    Institute of Scientific and Technical Information of China (English)

    Yanli Liu; Ming Li; Chao Han; Fengxia Wu; Bingkun Tu; Pingfang Yang

    2013-01-01

    Consumption of arsenic contaminated water and cereals is a serious threat to humans all over the world. Rice (Oryza sativa“Nipponbare”), as a main cereal crop, can accumulate arsenic more than 10-fold that of in other cereals. To gain a comprehensive understanding of the response of rice subjected to 100 mM arsenate stress, a comparative proteomic analysis of rice shoots in combination with morphological and biochemical investigations have been performed in this study. The results demonstrated that arsenate suppressed the growth of rice seedlings, destroyed the cellular ultra-structure and changed the homeostasis of reactive oxygen species. Moreover, a total of 38 differentially displayed proteins, which were mainly involved in metabolism, redox and protein-metabolism, were identified. The data suggest the arsenic can inhibit rice growth through negatively affecting chloroplast structure and photosynthesis. In addition, upregulation of the proteins involved in redox and protein metabolism might help the rice to be resistant or tolerant to arsenic toxicity. In general, this study improves our understanding about the rice arsenic responsive mechanism.

  16. Fast removal of high quantities of toxic arsenate via cationic p(APTMACl) microgels.

    Science.gov (United States)

    Rehman, Saif Ur; Siddiq, Mohammed; Al-Lohedan, Hamad; Aktas, Nahit; Sahiner, Mehtap; Demirci, Sahin; Sahiner, Nurettin

    2016-01-15

    Hydrogels are resourceful materials and can be prepared in different morphology, size, surface charge and porosity adopting different polymerization techniques and reaction conditions. The cationic poly(3-acrylamidopropyl)trimethylammonium chloride (p(APTMACl)) microgels were synthesized by photo-initiated inverse suspension polymerization technique. These microgels were utilized as absorbents for the removal of toxic arsenate (As) from different aqueous environments. The experimental parameters affecting absorption efficiency were investigated, and it was demonstrated that these types of microgels are highly efficient in removing arsenate anions from different aqueous environments compared to the previously reported bulk hydrogel, and cryogel of the same material. A removal efficiency of approximately 97.25% was obtained by immersing 0.5 g microgel in 250 ppm 100 mL solution of arsenate anions for 60 min. Both Langmuir and Freundlich adsorption isotherms were applied to adsorption of arsenate anions by p(APTMACl) microgels, and the Langmuir isotherm was a better representation of the adsorption of arsenate with a high value of R(2) (0.9982). Furthermore, mag-p(APTMACl) microgels were synthesized for the adsorption of arsenate anions to provide easy removal of the microgel composite by using an externally applied magnetic field. Furthermore, re-usability of the p(APTMACl) microgels was also investigated for the adsorption of arsenate anions. PMID:26513320

  17. Human brain aldehyde reductases: relationship to succinic semialdehyde reductase and aldose reductase.

    Science.gov (United States)

    Hoffman, P L; Wermuth, B; von Wartburg, J P

    1980-08-01

    Human brain contains multiple forms of aldehyde-reducing enzymes. One major form (AR3), as previously shown, has properties that indicate its identity with NADPH-dependent aldehyde reductase isolated from brain and other organs of various species; i.e., low molecular weight, use of NADPH as the preferred cofactor, and sensitivity to inhibition by barbiturates. A second form of aldehyde reductase ("SSA reductase") specifically reduces succinic semialdehyde (SSA) to produce gamma-hydroxybutyrate. This enzyme form has a higher molecular weight than AR3, and uses NADH as well as NADPH as cofactor. SSA reductase was not inhibited by pyrazole, oxalate, or barbiturates, and the only effective inhibitor found was the flavonoid quercetine. Although AR3 can also reduce SSA, the relative specificity of SSA reductase may enhance its in vivo role. A third form of human brain aldehyde reductase, AR2, appears to be comparable to aldose reductases characterized in several species, on the basis of its activity pattern with various sugar aldehydes and its response to characteristic inhibitors and activators, as well as kinetic parameters. This enzyme is also the most active in reducing the aldehyde derivatives of biogenic amines. These studies suggest that the various forms of human brain aldehyde reductases may have specific physiological functions. PMID:6778961

  18. Quantitative proteomic analysis of Dunaliella salina upon acute arsenate exposure.

    Science.gov (United States)

    Ge, Ying; Ning, Zhibin; Wang, Ya; Zheng, Yanheng; Zhang, Chunhua; Figeys, Daniel

    2016-02-01

    Dunaliella salina is resistant to arsenic (As) and can accumulate a large amount of this highly toxic metalloid in cells. To study the mechanisms of As tolerance, a label-free, LC-MS/MS-based proteomic approach was applied for the first time to identify and quantify differentially expressed proteins from D. salina exposed to 11.2 mg L(-1) arsenate (As(V)) for 72 h. The intracellular As content reached 19.8 mg kg(-1), leading to a significant increase of lipid peroxidation in cells and a 7.4% growth reduction of this microalga. Sixty-five proteins were differentially expressed (p defense, phosphate transport and membrane trafficking, and amino acid synthesis. Taken together, this study provides novel insights on the As(V) detoxification in D. salina. PMID:26688246

  19. Respiratory Failure

    Science.gov (United States)

    Respiratory failure happens when not enough oxygen passes from your lungs into your blood. Your body's organs, such ... brain, need oxygen-rich blood to work well. Respiratory failure also can happen if your lungs can't ...

  20. Characterization of ferric arsenate-sulfate compounds: Implications for arsenic control in refractory gold processing residues

    Czech Academy of Sciences Publication Activity Database

    Paktunc, D.; Majzlan, J.; Palatinus, Lukáš; Dutrizac, J.; Klementová, Mariana; Poirier, G.

    2013-01-01

    Roč. 98, č. 4 (2013), s. 554-565. ISSN 0003-004X Institutional support: RVO:68378271 Keywords : arsenic * ferric arsenate sulfate * autoclave residue * hydrometallurgy Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.059, year: 2013

  1. Two Lactococcus lactis thioredoxin paralogues play different roles in responses to arsenate and oxidative stress

    DEFF Research Database (Denmark)

    Efler, Petr; Kilstrup, Mogens; Johnsen, Stig;

    2015-01-01

    Thioredoxin (Trx) maintains intracellular thiol groups in a reduced state and is involved in a wide range of cellular processes, including ribonucleotide reduction, sulphur assimilation, oxidative stress responses and arsenate detoxification. The industrially important lactic acid bacterium...

  2. Focused ion beam analysis of banana peel and its application for arsenate ion removal

    International Nuclear Information System (INIS)

    Banana peel, a common fruit waste, has been investigated for its ability to remove arsenate ions from ground water as a function of pH, contact time, and initial metal ion concentration. Focused ion beam (FIB) analysis revealed the internal morphology of the banana peels. Arsenate ions were entered into micropores of banana peel. pH was seen to have no effect on the sorption process. Retained species were eluted using 5 mL of 2 M H/sub 2/SO/sub 4/. The kinetics of sorption were observed to follow the pseudo first order rate equation. The sorption data followed Freundlich and D-R isotherms. The energy value obtained from the D-R isotherms indicated that the sorption was physical in nature for arsenate species. Our study has shown that banana peel has the ability to remove arsenate species from ground water samples. (author)

  3. Adsorption of arsenate from aqueous solution by rice husk-based adsorbent

    Science.gov (United States)

    Khan, Taimur; Chaudhuri, Malay

    2013-06-01

    Rice husk-based adsorbent (RHBA) was prepared by burning rice husk in a muffle furnace at 400°C for 4 h and adsorption of arsenate by the RHBA from aqueous solution was examined. Batch adsorption test showed that extent of arsenate adsorption depended on contact time and pH. Equilibrium adsorption was attained in 60 min, with maximum adsorption occurring at pH 7. Equilibrium adsorption data were well described by the Freundlich isotherm model. Freundlich constants Kf and 1/n were 3.62 and 2, respectively. The RHBA is effective in the adsorption of arsenate from water and is a potentially suitable filter medium for removing arsenate from groundwater at wells or in households.

  4. Adsorption of arsenate from aqueous solution by rice husk-based adsorbent

    International Nuclear Information System (INIS)

    Rice husk-based adsorbent (RHBA) was prepared by burning rice husk in a muffle furnace at 400°C for 4 h and adsorption of arsenate by the RHBA from aqueous solution was examined. Batch adsorption test showed that extent of arsenate adsorption depended on contact time and pH. Equilibrium adsorption was attained in 60 min, with maximum adsorption occurring at pH 7. Equilibrium adsorption data were well described by the Freundlich isotherm model. Freundlich constants Kf and 1/n were 3.62 and 2, respectively. The RHBA is effective in the adsorption of arsenate from water and is a potentially suitable filter medium for removing arsenate from groundwater at wells or in households.

  5. Arsenate adsorption and desorption kinetics on a Fe(III)-modified montmorillonite

    International Nuclear Information System (INIS)

    Graphical abstract: Arsenate adsorption is much higher in Fe-exchanged montmorillonite (Fe-M) than in Na-exchanged montmorillonite (Na-M). The adsorption takes place in a two-step mechanism. Research highlights: → Adsorption-desorption kinetics of arsenate on a Fe(III)-modified montmorillonite is reported. → Fe(III) species are the responsible for arsenate adsorption. → The adsorption takes place in a two-step mechanism. → Adsorption and desorption studies reflect the presence of externally and internally adsorbed arsenate. → Fe(III) species in Fe-M are more efficient in binding arsenate than in ferrihydrite or goethite. - Abstract: The adsorption-desorption kinetics of arsenate on a Fe(III)-modified montmorillonite (Fe-M) was studied at different arsenate concentrations, pH and stirring rates. The synthesized solid was a porous sample with Fe(III) present as a mix of monomeric and polymeric Fe(III) species in the interlayer and on the external surface. Adsorption took place in a two-step mechanism, with an initial fast binding of arsenate to Fe(III) species at the external surface (half-lives of 1 min or shorter) followed by a slower binding to less accessible Fe(III) species in pores and the interlayer (half-lives of around 1 h). Desorption kinetics also reflected the presence of externally and internally adsorbed arsenate. At pH 6 the maximum adsorbed arsenate was 52 μmol/g, a value that is low as compared to adsorption on ferrihydrite (700 μmol/g) and goethite (192-220 μmol/g). However, since the Fe(III) content of Fe-M is much lower than that of ferrihydrite and goethite, Fe(III) species in Fe-M are more efficient in binding arsenate than in ferrihydrite or goethite (one As atom is attached every 8.95 iron atoms). This high binding efficiency indicates that Fe(III) species are well spread on montmorillonite, forming small oligomeric species or surface clusters containing just a few iron atoms.

  6. Behavior of Eucalyptus urophylla and Eucalyptus citriodora Seedlings Grown in Soil Contaminated by Arsenate

    OpenAIRE

    Roseli Freire de Melo; Luiz Eduardo Dias; Igor Rodrigues de Assis

    2016-01-01

    ABSTRACT Persistent areas of tailings and deposits from coal and gold mining may present high levels of arsenic (As), mainly in the arsenate form, endangering the environment and human health. The establishment of vegetation cover is a key step to reclaiming these environments. Thus, this study aimed to evaluate the potential of Eucalyptus urophylla and E. citriodora seedlings for use in phytoremediation programs of arsenate-contaminated areas. Soil samples were incubated at increasing rates ...

  7. A mechanistic study of arsenate removal from artificially contaminated clay soils by electrokinetic remediation.

    Science.gov (United States)

    Suzuki, Tasuma; Moribe, Mai; Okabe, Yohhei; Niinae, Masakazu

    2013-06-15

    Batch desorption experiments and bench-scale electrokinetic experiments were performed to elucidate the electrokinetic remediation mechanisms of arsenate from artificially contaminated kaolinite. The electrokinetic experiments in which a constant voltage was applied demonstrated that high soil pH favored arsenate remediation with respect to both the remediation time and electricity consumption. It was also demonstrated that applying a pulse voltage (1 h ON, 1 h OFF) significantly improved the electricity consumption efficiency when the soil pH was maintained at the initial value during the experiments; this trend was not observed when the soil pH was gradually increased from the cathode side. These electrokinetic experimental results, with the support of arsenate desorption data obtained from batch experiments, indicate that the remediation rate-limiting step varied with soil pH. When the soil pH was maintained at the initial value of 7.2 during the experiments, arsenate desorption was the remediation rate-limiting step rather than the migration of dissolved arsenate toward the anode. Conversely, when the cathode pH was not controlled and the soil pH was correspondingly increased gradually from the cathode side, the migration of hydroxyl and desorbed arsenate ions toward the anode played a more important role in the control of the overall remediation efficiency. PMID:23643955

  8. Respiratory Failure

    OpenAIRE

    Özyılmaz, Ezgi

    2014-01-01

    The main function of the lungs is to maintain the exchange between the pulmonary capillary and the air in the alveoli. By this way, the arteriel oxygen and carbondioxide tension remains constant. Respiratory failure is a syndrome which is defined as the loss of the ability of respiratory system to exchange oxygen and carbondioxide elimination function. The main pathophysiological causes of respiratory failure include ventilation-perfusion mismatch, alveolar hypoventilation, impaired diffusion...

  9. Adsorption of arsenate on Cu/Mg/Fe/La layered double hydroxide from aqueous solutions

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Yanwei [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); Zhu, Zhiliang, E-mail: zzl@tongji.edu.cn [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China); Qiu, Yanling [Key Laboratory of Yangtze River Water Environment, Ministry of Education, Tongji University, Shanghai 200092 (China); Zhao, Jianfu [State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, Shanghai 200092 (China)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer A novel layered double hydroxide containing lanthanum (Cu/Mg/Fe/La-LDH) has been synthesized. Black-Right-Pointing-Pointer The average pore size of the materials with about 16 nm indicated that the mesoporous structures existed in the Cu/Mg/Fe/La-LDHs. Black-Right-Pointing-Pointer The adsorption capacity of As(V) increased with the increment of La{sup 3+} content in the LDH. Black-Right-Pointing-Pointer The maximum adsorption capacity of the synthesized Cu/Mg/Fe/La-LDH for arsenate was 43.5 mg/g. - Abstract: A novel layered double hydroxide containing lanthanum (Cu/Mg/Fe/La-LDH) has been synthesized and used for the removal of arsenate from aqueous solutions. The purpose of incorporation of La{sup 3+} into LDHs was tried to enhance the uptake efficiency of arsenate and broaden the application field of LDHs functional materials. Effects of various physico-chemical factors such as solution pH, adsorbent dosage, contact time and initial arsenate concentrations on the adsorption of arsenate onto Cu/Mg/Fe/La-LDH were investigated. Results showed that the removal efficiency of arsenate increased with the increment of the lanthanum content in Cu/Mg/Fe/La-LDH adsorbents, and the optimized lanthanum content was 20% of the total trivalent metals composition (Fe{sup 3+} and La{sup 3+}). The adsorption isotherms can be well described by Langmuir equation, and the adsorption kinetics of arsenate followed the pseudo-second-order kinetic model. Coexistent ions such as HPO{sub 4}{sup 2-}, CO{sub 3}{sup 2-}, SO{sub 4}{sup 2-}, Cl{sup -} and NO{sub 3}{sup -} exhibited obvious competition with arsenate for the adsorption on Cu/Mg/Fe/La-LDH. The solution pH significantly affected the removal efficiency, which was closely related to the change of arsenate species distribution under different pH conditions. The predominant adsorption mechanism can be mainly attributed to the processes including ion exchange and layer ligand exchange.

  10. Respiratory mechanics

    CERN Document Server

    Wilson, Theodore A

    2016-01-01

    This book thoroughly covers each subfield of respiratory mechanics: pulmonary mechanics, the respiratory pump, and flow. It presents the current understanding of the field and serves as a guide to the scientific literature from the golden age of respiratory mechanics, 1960 - 2010. Specific topics covered include the contributions of surface tension and tissue forces to lung recoil, the gravitational deformation of the lung, and the interdependence forces that act on pulmonary airways and blood vessels. The geometry and kinematics of the ribs is also covered in detail, as well as the respiratory action of the external and internal intercostal muscles, the mechanics of the diaphragm, and the quantitative compartmental models of the chest wall is also described. Additionally, flow in the airways is covered thoroughly, including the wave-speed and viscous expiratory flow-limiting mechanisms; convection, diffusion and the stationary front; and the distribution of ventilation. This is an ideal book for respiratory ...

  11. Arsenate removal with 3-mercaptopropanoic acid-coated superparamagnetic iron oxide nanoparticles.

    Science.gov (United States)

    Morillo, D; Uheida, A; Pérez, G; Muhammed, M; Valiente, M

    2015-01-15

    In the present work, superparamagnetic iron oxide nanoparticles (SPION) surface-coated with 3-mercaptopropanoic acid (3-MPA) were prepared and their feasibility for the removal of arsenate from dilute aqueous solutions was demonstrated. The synthesized 3-MPA-coated SPION was characterized using transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and Fourier transform infra-red spectrometry (FTIR). Separation efficiency of the coated nanoparticles and the equilibrium isotherm of arsenate adsorption were investigated. The obtained results reveal the arsenate adsorption to be highly pH-dependent, and the maximum adsorption was attained in less than 60 min. The resulting increase of 3-MPA-coated SPION adsorption capacity to twice the adsorption capacity of SPION alone under the same conditions is attributed to the increase of active adsorption sites. An adsorption reaction is proposed. On the other hand, efficient recovery of arsenate from the loaded nanoparticles was achieved using nitric acid (HNO3) solution, which also provides a concentration over the original arsenate solution. PMID:25454446

  12. Fabrication and evolution of multilayer silver nanofilms for surface-enhanced Raman scattering sensing of arsenate

    Directory of Open Access Journals (Sweden)

    Li Jinwei

    2011-01-01

    Full Text Available Abstract Surface-enhanced Raman scattering (SERS has recently been investigated extensively for chemical and biomolecular sensing. Multilayer silver (Ag nanofilms deposited on glass slides by a simple electroless deposition process have been fabricated as active substrates (Ag/GL substrates for arsenate SERS sensing. The nanostructures and layer characteristics of the multilayer Ag films could be tuned by varying the concentrations of reactants (AgNO3/BuNH2 and reaction time. A Ag nanoparticles (AgNPs double-layer was formed by directly reducing Ag+ ions on the glass surfaces, while a top layer (3rd-layer of Ag dendrites was deposited on the double-layer by self-assembling AgNPs or AgNPs aggregates which had already formed in the suspension. The SERS spectra of arsenate showed that characteristic SERS bands of arsenate appear at approximately 780 and 420 cm-1, and the former possesses higher SERS intensity. By comparing the peak heights of the approximately 780 cm-1 band of the SERS spectra, the optimal Ag/GL substrate has been obtained for the most sensitive SERS sensing of arsenate. Using this optimal substrate, the limit of detection (LOD of arsenate was determined to be approximately 5 μg·l-1.

  13. Genetics Home Reference: sepiapterin reductase deficiency

    Science.gov (United States)

    Skip to main content Your Guide to Understanding Genetic Conditions Enable Javascript for addthis links to activate. ... Conditions Genes Chromosomes & mtDNA Resources Help Me Understand Genetics Home Health Conditions sepiapterin reductase deficiency sepiapterin reductase ...

  14. Differences in the immobilization of arsenite and arsenate by calcite

    Science.gov (United States)

    Yokoyama, Yuka; Tanaka, Kazuya; Takahashi, Yoshio

    2012-08-01

    The sorption and coprecipitation experiments of arsenic (As) with calcite coupled with determinations of the chemical state of As both in the reaction fluid and in calcite were conducted to investigate the influence of the As oxidation state on its immobilization into calcite. The oxidation states of As in calcite and water were determined via As K-edge XANES and HPLC-ICP-MS analysis, respectively. The results of the sorption experiments at pH 8.2 show that only As(V) is distributed to calcite regardless of the As oxidation state in the solution. In coprecipitation experiments, As(V) is preferentially incorporated into calcite over a wide range of pH (7-12). On the other hand, the incorporation of As(III) into calcite is not observed at circumneutral pH. This difference between As(III) and As(V) is attributed to the fact that their dissolved species are neutral vs. negatively charged, respectively, at circumneutral pH (arsenite as H3AsO3; arsenate as H2AsO4- or HAsO42-). As the pH increases (>9), up to 33% of As(III)/Astotal ratio is partitioned into calcite or a precursor of calcite (metastable vaterite formed during the early stage of precipitation). The higher interaction of As with calcite at an alkaline pH compared with circumneutral pH is due to the negative charge of As(III) at alkaline pH. However, the As(III)/Astotal ratio decreases as time progresses and only As(V) can be found finally in calcite. The ratio of distribution coefficients of As(III) and As(V) into calcite (KAs(V)/KAs(III)) at pH ˜7 is larger than 2.1 × 103, suggesting that the oxidation state of As is a significant issue in considering the interaction between As and calcite in groundwater. Moreover, low KAs(III) shows that the sequestration of As via coprecipitation with calcite is not an important chemical process under reducing conditions, such as in the groundwaters in Bangladesh and other As-contaminated areas where As(III) is the dominant dissolved species of As. In the system spiked

  15. Removal of arsenate from water by using an Fe-Ce oxide adsorbent: Effects of coexistent fluoride and phosphate

    International Nuclear Information System (INIS)

    The Langmuir two-site equation, X-ray photoelectron spectroscopy, and extended X-ray absorption fine structure spectroscopy have been employed to study the competitive behaviors of fluoride (F) and phosphate (P) in relation to arsenate adsorption on an Fe-Ce adsorbent as well as the mechanisms involved. The two-site isotherm revealed the presence of two kinds of adsorption sites with different binding affinities for arsenate. Both the total and low-binding-energy maximum adsorption capacities (Q and Q1) of arsenate decreased significantly even at a molar ratio of As/P = 1:0.1. The coexistence of F, only influenced the total Q of arsenate at high simultaneous F concentrations. The fact that Fe-Ce released 0.15-0.24 mmol sulfate for every mmol arsenate adsorbed suggested that, while sulfate groups might have played a role for adsorption, surface hydroxyl groups should be the major active sites. The XPS results indicated that arsenate and P are mainly adsorbed through the substitution of Fe surface active sites, while F is mainly adsorbed through substitution of Ce surface active sites. The As k-edge EXAFS data show that the second peak of Fe-Ce after arsenate adsorption is As-Fe shell, which further supported that arsenate adsorption occurs mainly at the Fe surface active sites.

  16. Arsenate removal by layered double hydroxides embedded into spherical polymer beads: Batch and column studies.

    Science.gov (United States)

    Nhat Ha, Ho Nguyen; Kim Phuong, Nguyen Thi; Boi An, Tran; Mai Tho, Nguyen Thi; Ngoc Thang, Tran; Quang Minh, Bui; Van Du, Cao

    2016-01-01

    In this study, the performance of poly(layered double hydroxides) [poly(LDHs)] beads as an adsorbent for arsenate removal from aqueous solution was investigated. The poly(LDHs) beads were prepared by immobilizing LDHs into spherical alginate/polyvinyl alcohol (PVA)-glutaraldehyde beads (spherical polymer beads). Batch adsorption studies were conducted to assess the effect of contact time, solution pH, initial arsenate concentrations and co-existing anions on arsenate removal performance. The potential reuse of these poly(LDHs) beads was also investigated. Approximately 79.1 to 91.2% of arsenic was removed from an arsenate solution (50 mg As L(-1)) by poly(LDHs). The adsorption data were well described by the pseudo-second-order kinetics model and the Langmuir isotherm model, and the adsorption capacities of these poly(LDHs) beads at pH 8 were from 1.64 to 1.73 mg As g(-1), as calculated from the Langmuir adsorption isotherm. The adsorption ability of the poly(LDHs) beads decreased by approximately 5-6% after 5 adsorption-desorption cycles. Phosphates markedly decreased arsenate removal. The effect of co-existing anions on the adsorption capacity declined in the following order: HPO4 (2-) > HCO3 (-) > SO4 (2-) > Cl(-). A fixed-bed column study was conducted with real-life arsenic-containing water. The breakthrough time was found to be from 7 to 10 h. Under optimized conditions, the poly(LDHs) removed more than 82% of total arsenic. The results obtained in this study will be useful for further extending the adsorbents to the field scale or for designing pilot plants in future studies. From the viewpoint of environmental friendliness, the poly(LDHs) beads are a potential cost-effective adsorbent for arsenate removal in water treatment. PMID:26818806

  17. Perchlorate Reductase Is Distinguished by Active Site Aromatic Gate Residues.

    Science.gov (United States)

    Youngblut, Matthew D; Tsai, Chi-Lin; Clark, Iain C; Carlson, Hans K; Maglaqui, Adrian P; Gau-Pan, Phonchien S; Redford, Steven A; Wong, Alan; Tainer, John A; Coates, John D

    2016-04-22

    Perchlorate is an important ion on both Earth and Mars. Perchlorate reductase (PcrAB), a specialized member of the dimethylsulfoxide reductase superfamily, catalyzes the first step of microbial perchlorate respiration, but little is known about the biochemistry, specificity, structure, and mechanism of PcrAB. Here we characterize the biophysics and phylogeny of this enzyme and report the 1.86-Å resolution PcrAB complex crystal structure. Biochemical analysis revealed a relatively high perchlorate affinity (Km = 6 μm) and a characteristic substrate inhibition compared with the highly similar respiratory nitrate reductase NarGHI, which has a relatively much lower affinity for perchlorate (Km = 1.1 mm) and no substrate inhibition. Structural analysis of oxidized and reduced PcrAB with and without the substrate analog SeO3 (2-) bound to the active site identified key residues in the positively charged and funnel-shaped substrate access tunnel that gated substrate entrance and product release while trapping transiently produced chlorate. The structures suggest gating was associated with shifts of a Phe residue between open and closed conformations plus an Asp residue carboxylate shift between monodentate and bidentate coordination to the active site molybdenum atom. Taken together, structural and mutational analyses of gate residues suggest key roles of these gate residues for substrate entrance and product release. Our combined results provide the first detailed structural insight into the mechanism of biological perchlorate reduction, a critical component of the chlorine redox cycle on Earth. PMID:26940877

  18. Phosphate and arsenate removal efficiency by thermostable ferritin enzyme from Pyrococcus furiosus using radioisotopes

    KAUST Repository

    Sevcenco, Ana-Maria

    2015-03-13

    Oxo-anion binding properties of the thermostable enzyme ferritin from Pyrococcus furiosus were characterized with radiography. Radioisotopes 32P and 76As present as oxoanions were used to measure the extent and the rate of their absorption by the ferritin. Thermostable ferritin proved to be an excellent system for rapid phosphate and arsenate removal from aqueous solutions down to residual concentrations at the picomolar level. These very low concentrations make thermostable ferritin a potential tool to considerably mitigate industrial biofouling by phosphate limitation or to remove arsenate from drinking water.

  19. Characterization of the respiratory chain of Helicobacter pylori

    DEFF Research Database (Denmark)

    Chen, M; Andersen, L P; Zhai, L; Kharazmi, A

    1999-01-01

    The respiratory chain of Helicobacter pylori has been investigated. The total insensitivity of activities of NADH dehydrogenase to rotenone and of NADH-cytochrome c reductase to antimycin is indicative of the absence of the classical complex I of the electron transfer chain in this bacterium. NADPH......-dependent respiration was significantly stronger than NADH-dependent respiration, indicating that this is a major respiratory electron donor in H. pylori. Fumarate and malonate exhibited a concentration-dependent inhibitory effect on the activity of succinate dehydrogenase. The activity of succinate-cytochrome c...... reductase was inhibited by antimycin, implying the presence of a classical pathway from complex II to complex III in this bacterium. The presence of NADH-fumarate reductase (FRD) was demonstrated in H. pylori and fumarate could reduce H2O2 production from NADH, indicating fumarate to be an endogenous...

  20. Respiratory Failure

    Directory of Open Access Journals (Sweden)

    Ezgi Ozyilmaz

    2014-06-01

    Full Text Available The main function of the lungs is to maintain the exchange between the pulmonary capillary and the air in the alveoli. By this way, the arteriel oxygen and carbondioxide tension remains constant. Respiratory failure is a syndrome which is defined as the loss of the ability of respiratory system to exchange oxygen and carbondioxide elimination function. The main pathophysiological causes of respiratory failure include ventilation-perfusion mismatch, alveolar hypoventilation, impaired diffusion capacity and increased shunt. A number of diseases may result in respiratory failure by different pathophysiological reasons. The most common causes are Type 1 (hypoxemic and Type 2 (hypercapnic respiratory failure. When suspected with clinical signs and symptoms, the diagnosis should be confirmed with arterial blood gases. At this step, other diagnostic interventions, which could be performed, may be used to enlighten the underlying pathophysiological cause. Although the main therapeutic approach is similar, specific treatment are also required based on the underlying cause. The basic pathophysiological points, diagnosis and basic treatment approach have been evaluated in this review article. [Cukurova Med J 2014; 39(3.000: 428-442

  1. Bioaccumulation and oxidative stress in Daphnia magna exposed to arsenite and arsenate.

    Science.gov (United States)

    Fan, Wenhong; Ren, Jinqian; Li, Xiaomin; Wei, Chaoyang; Xue, Feng; Zhang, Nan

    2015-11-01

    Arsenic pollution and its toxicity to aquatic organisms have attracted worldwide attention. The bioavailability and toxicity of arsenic are highly related to its speciation. The present study investigated the differences in bioaccumulation and oxidative stress responses in an aquatic organism, Daphnia magna, induced by 2 inorganic arsenic species (As(III) and As(V)). The bioaccumulation of arsenic, Na(+) /K(+) -adenosine triphosphatase (ATPase) activity, reactive oxygen species (ROS) content, total superoxide dismutase (SOD) activity, total antioxidative capability, and malondialdehyde content in D. magna were determined after exposure to 500 µg/L of arsenite and arsenate for 48 h. The results showed that the oxidative stress and antioxidative process in D. magna exposed to arsenite and arsenate could be divided into 3 phases, which were antioxidative response, oxidation inhibition, and antioxidative recovery. In addition, differences in bioaccumulation, Na(+) /K(+) -ATPase activity, and total SOD activity were also found in D. magna exposed to As(III) and As(V). These differences might have been the result of the high affinity of As(III) with sulfhydryl groups in enzymes and the structural similarity of As(V) to phosphate. Therefore, arsenate could be taken up by organisms through phosphate transporters, could substitute for phosphate in biochemical reactions, and could lead to a change in the bioaccumulation of arsenic and activity of enzymes. These characteristics were the possible reasons for the different toxicity mechanisms in the oxidative stress process of arsenite and arsenate. PMID:26084717

  2. Arsenate tolerance in Silene paradoxa does not rely on phytochelatin-dependent sequestration

    International Nuclear Information System (INIS)

    Arsenate tolerance, As accumulation and As-induced phytochelatin accumulation were compared in populations of Silene paradoxa, one from a mine site enriched in As, Cu and Zn, the other from an uncontaminated site. The mine population was significantly more arsenate-tolerant. Arsenate uptake and root-to-shoot transport were slightly but significantly higher in the non-mine plants. The difference in uptake was quantitatively insufficient to explain the difference in tolerance between the populations. As accumulation in the roots was similar in both populations, but the mine plants accumulated much less phytochelatins than the non-mine plants. The mean phytochelatin chain length, however, was higher in the mine population, possibly due to a constitutively lower cellular glutathione level. It is argued that the mine plants must possess an arsenic detoxification mechanism other than arsenate reduction and subsequent phytochelatin-based sequestration. This alternative mechanism might explain at least some part of the superior tolerance in the mine plants. - Neither decreased uptake nor phytochelatins seem to play a role in the As tolerance in Silene paradoxa

  3. XAFS study of starch-stabilized magnetite nanoparticles and surface speciation of arsenate

    International Nuclear Information System (INIS)

    It has been shown that starch can effectively stabilize nanoscale magnetite particles, and starch-stabilized magnetite nanoparticles (SMNP) are promising for in situ remediation of arsenic-contaminated soils. However, a molecular level understanding has been lacking. Here, we carried out XAFS studies to bridge this knowledge gap. Fe K-edge XAFS spectra indicated that the Fe-O and Fe-Fe coordination numbers of SMNP were lower than those for bare magnetite particles, and these coordination numbers decreased with increasing starch concentration. The decrease in the average coordination number at elevated stabilizer concentration was attributed to the increase in the surface-to-volume ratio. Arsenic K-edge XAFS spectra indicated that adsorbed arsenate on SMNP consisted primarily of binuclear bidentate (BB) complexes and monodentate mononuclear (MM) complexes. More BB complexes (energetically more favorable) were observed at higher starch concentrations, indicating that SMNP not only offered greater adsorption surface area, but also stronger adsorption affinity toward arsenate. - Graphical abstract: Display Omitted Highlights: → Starch as a stabilizer of magnetite nanoparticles. → Characterization of starch-stabilized magnetite nanoparticles by XAFS. → Fe-O and Fe-Fe coordination numbers decreased with starch concentration increasing. → Ratio of two arsenate complexes adsorbed varied with starch concentration. → More binuclear bidentate arsenic complexes formed at higher starch concentrations. - The presence of starch leads to the formation of more effective adsorbing sites and stronger adsorption affinity of arsenate on magnetite nanoparticle surfaces.

  4. Accumulation of lead and arsenic by potato grown on lead-arsenate contaminated orchard soils

    Science.gov (United States)

    Concerns have been raised about the potential food chain transfer of metals in crops grown on historic orchard soils where lead arsenate pesticide was used. The objective of this study was to evaluate the uptake of lead and arsenic (As) by four potato (Solanum tuberosum L.) cultivars (Atlantic, Dar...

  5. SORPTION OF ARSENATE AND ARSENITE ON A RUTHENIUM COMPOUND: A MACROSCOPIC AND MICROSCOPIC STUDY

    Science.gov (United States)

    Sorption of arsenate and arsenite was examined on a ruthenium compound using macroscopic and microscopic techniques. Batch sorption experiments at pH 4,5,6, 7 and 8 were employed to construct constant solid solution ratio isotherms (CSI). After equilibration at the appropriate pH...

  6. Evaluating the performance of modified adsorbent of zero valent iron nanoparticles – Chitosan composite for arsenate removal from aqueous solutions

    Directory of Open Access Journals (Sweden)

    K Yaghmaeian

    2016-03-01

    Full Text Available Background and Objective: Arsenic is one of the most toxic pollutants in groundwater and surface water. Arsenic could have lots of adverse impacts on human health. Therefore, access to new technologies is required to achieve the arsenic standard. Materials and Methods: The present study was conducted at laboratory scale in non-continuous batches. The adsorbent of zero-valent iron nanoparticles -Chitosan was produced through reducing ferric iron by sodium borohydride (NaBH4 in the presence of chitosan as a stabilizer. At first, the effect of various parameters such as contact time (5-120 min, pH (3-10, adsorbent dose (0.3-3.5 g/L and initial concentration of arsenate (2-10 mg/L were investigated on process efficiency. Then optimum conditions in terms of contact time, pH, adsorbent dose and initial concentration of arsenate were determined by RSM method. Freundlich and Langmuir isotherm model equilibrium constant, pseudo-first and second order kinetic constants were calculated. The residual arsenate was measured y using ICP-AES. Results: The optimum values based on RSM for pH, absorbent dose, contact time, and initial concentration of arsenate were 7.16, 3.04 g/L, 91.48 min, and 9.71 mg/L respectively. Langmuir isotherm with R2= 0.9904 for Arsenate was the best graph for the experimental data. According to Langmuir isotherm model, the maximum amount of arsenate adsorption was 135.14mg/g. . The investigation of arsenate adsorption kinetics showed that arsenate adsorption follows the pseudo-second kinetics model. Conclusion: This research showed that the adsorption process is depended on pH. With increasing pH, the ability of amine groups in chitosan are decreased to protonation, caused to decrease the efficiency of arsenate removal at high pH.

  7. Competitive adsorption of arsenate and phosphate onto calcite; experimental results and modeling with CCM and CD-MUSIC

    Science.gov (United States)

    Sø, Helle Ugilt; Postma, Dieke; Jakobsen, Rasmus; Larsen, Flemming

    2012-09-01

    The competitive adsorption of arsenate and phosphate onto calcite was studied in batch experiments using calcite-equilibrated solutions. The solutions had circum-neutral pH (7-8.3) and covered a wide span in the activity of Ca2+ and CO32-. The results show that the adsorption of arsenate onto calcite is strongly reduced by the presence of phosphate, whereas phosphate adsorption is only slightly reduced by arsenate addition. Simultaneous and sequential addition (3 h apart) yields the same reduction in adsorption, underlining the high reversibility of the system. The reduction in adsorption of both arsenate and phosphate is most likely due to competition for the same sorption sites at the calcite surface, considering the similarity in sorption edges, pKa's and geometry of the two anions. The strong reduction in arsenate adsorption by competition with phosphate suggests that adsorption of arsenate onto calcite is of minor importance in most groundwater aquifers, as phosphate is often present at concentration levels sufficient to significantly reduce arsenate adsorption. The CD-MUSIC model for calcite was used successfully to model adsorption of arsenate and phosphate separately. By combining the models for single sorbate systems the competitive adsorption of phosphate and arsenate onto calcite in the binary system could be predicted. This is in contrast to the constant capacitance model (CCM) which under-predicted the competition when combining the models for single sorbate systems. This study clearly shows the importance of performing competitive adsorption studies for validation of multi-component models and for estimating the mobility of an ion in the environment.

  8. Effects of sodium arsenate exposure on liver fatty acid profiles and oxidative stress in rats.

    Science.gov (United States)

    Kharroubi, Wafa; Dhibi, Madiha; Haouas, Zohra; Chreif, Imed; Neffati, Fadoua; Hammami, Mohamed; Sakly, Rachid

    2014-02-01

    The present study aimed to evaluate the effect of arsenic on liver fatty acids (FA) composition, hepatotoxicity and oxidative status markers in rats. Male rats were randomly devised to six groups (n=10 per group) and exposed to sodium arsenate at a dose of 1 and 10 mg/l for 45 and 90 days. Arsenate exposure is associated with significant changes in the FA composition in liver. A significant increase of saturated fatty acids (SFA) in all treated groups (p<0.01) and trans unsaturated fatty acids (trans UFA) in rats exposed both for short term for 10 mg/l (p<0.05) and long term for 1 and 10 mg/l (p<0.001) was observed. However, the cis UFA were significantly decreased in these groups (p<0.05). A markedly increase of indicator in cell membrane viscosity expressed as SFA/UFA was reported in the treated groups (p<0.001). A significant increase in the level of malondialdehyde by 38.3 % after 90 days of exposure at 10 mg/l was observed. Compared to control rats, significant liver damage was observed at 10 mg/l of arsenate by increasing plasma marker enzymes after 90 days. It is through the histological investigations in hepatic tissues of exposed rats that these damage effects of arsenate were confirmed. The antioxidant perturbations were observed to be more important at groups treated by the high dose (p<0.05). An increase in the level of protein carbonyls was observed in all treated groups (p<0.05). The present study provides evidence for a direct effect of arsenite on FA composition disturbance causing an increase of SFA and TFAs isomers, liver dysfunction and oxidative stress. Therefore, arsenate can lead to hepatic damage and propensity towards liver cancer. PMID:23949113

  9. Behavior of Eucalyptus urophylla and Eucalyptus citriodora Seedlings Grown in Soil Contaminated by Arsenate

    Directory of Open Access Journals (Sweden)

    Roseli Freire Melo

    2016-01-01

    Full Text Available ABSTRACT Persistent areas of tailings and deposits from coal and gold mining may present high levels of arsenic (As, mainly in the arsenate form, endangering the environment and human health. The establishment of vegetation cover is a key step to reclaiming these environments. Thus, this study aimed to evaluate the potential of Eucalyptus urophylla and E. citriodora seedlings for use in phytoremediation programs of arsenate-contaminated areas. Soil samples were incubated at increasing rates (0, 50, 100, 200 and 400 mg dm-3 of arsenic (arsenate form, using Na2HAsO4 for 15 days. The seedlings were produced in a substrate (vermiculite + sawdust and were transplanted to the pots with soil three months after seed germination. The values of plant height and diameter were taken during transplanting and 30, 60 and 90 days after transplanting. In the last evaluation, the total leaf area and biomass of shoots and roots were also determined. The values of available As in soil which caused a 50 % dry matter reduction (TS50%, the As translocation index (TI from the roots to the shoot of the plants, and its bioconcentration factor (BF were also calculated. Higher levels of arsenate in the soil significantly reduced the dry matter production of roots and shoots and the height of both species, most notably in E. urophylla plants. The highest levels of As were found in the root, with higher values for E. citriodora (ranging from 253.86 to 400 mg dm-3. The TI and BF were also reduced with As doses, but the values found in E. citriodora were significantly higher than in E. urophylla. E. citriodora plants presented a higher capacity to tolerate As and translocate it to the shoot than E. urophylla. Although these species cannot be considered as hyperaccumulators of As, E. citriodora presented the potential to be used in phytoremediation programs in arsenate-contaminated areas due to the long-term growth period of this species.

  10. Fatty acyl-CoA reductase

    Energy Technology Data Exchange (ETDEWEB)

    Reiser, Steven E.; Somerville, Chris R.

    1998-12-01

    The present invention relates to bacterial enzymes, in particular to an acyl-CoA reductase and a gene encoding an acyl-CoA reductase, the amino acid and nucleic acid sequences corresponding to the reductase polypeptide and gene, respectively, and to methods of obtaining such enzymes, amino acid sequences and nucleic acid sequences. The invention also relates to the use of such sequences to provide transgenic host cells capable of producing fatty alcohols and fatty aldehydes.

  11. RESPIRATORY SYSTEM

    Institute of Scientific and Technical Information of China (English)

    2004-01-01

    9. 1 Upper respiratory tract disease and bronchial asthma2004223 Inhibitive effect on airway mucus overproduction of DNA vaccine based on xenogeneic homologous calcium-activated chloride channel in asthmatic mice. SONG Liqiang (宋立强), et al. Dept Respir Med, Xijing Hosp , 4th Milit Med Univ, Xi’an 710032. Natl Med J China 2004;84(4):329-333.

  12. Microbial arsenic metabolism: New twists on an old poison

    Science.gov (United States)

    Stolz, J.F.; Basu, P.; Oremland, R.S.

    2010-01-01

    Phylogenetically diverse microorganisms metabolize arsenic despite its toxicity and are part of its robust iogeochemical cycle. Respiratory arsenate reductase is a reversible enzyme, functioning in some microbes as an arsenate reductase but in others as an arsenite oxidase. As(III) can serve as an electron donor for anoxygenic photolithoautotrophy and chemolithoautotrophy. Organoarsenicals, such as the feed additive roxarsone, can be used as a source of energy, releasing inorganic arsenic.

  13. Oxalic acid as an assisting agent for the electrodialytic remediation of chromated copper arsenate treated timber waste

    DEFF Research Database (Denmark)

    Ribeiro, Alexandra B.; Mateus, Eduardo P.; Ottosen, Lisbeth M.

    1999-01-01

    The electrodialytic process is proposed as a technique for the remediation of chromated copper arsenate treated timber waste, using oxalic acid as assisting agent. The method prowed succesfull 93% Cu, 95% Cr and 99% As was removed from the timber.......The electrodialytic process is proposed as a technique for the remediation of chromated copper arsenate treated timber waste, using oxalic acid as assisting agent. The method prowed succesfull 93% Cu, 95% Cr and 99% As was removed from the timber....

  14. Respiratory Distress

    Science.gov (United States)

    1976-01-01

    The University of Miami School of Medicine asked the Research Triangle Institute for assistance in improvising the negative pressure technique to relieve respiratory distress in infants. Marshall Space Flight Center and Johnson Space Center engineers adapted this idea to the lower-body negative-pressure system seals used during the Skylab missions. Some 20,000 babies succumb to respiratory distress in the U.S. each year, a condition in which lungs progressively lose their ability to oxygenate blood. Both positive and negative pressure techniques have been used - the first to force air into lungs, the second to keep infant's lungs expanded. Negative pressure around chest helps the baby expand his lungs and maintain proper volume of air. If doctors can keep the infant alive for four days, the missing substance in the lungs will usually form in sufficient quantity to permit normal breathing. The Skylab chamber and its leakproof seals were adapted for medical use.

  15. Arsenate impact on the metabolite profile, production and arsenic loading of xylem sap in cucumbers (Cucumis sativus L.

    Directory of Open Access Journals (Sweden)

    KalleUroic

    2012-04-01

    Full Text Available Arsenic uptake and translocation studies on xylem sap focus generally on the concentration and speciation of arsenic in the xylem. Arsenic impact on the xylem sap metabolite profile and its production during short term exposure has not been reported in detail. To investigate this, cucumbers were grown hydroponically and arsenate (AsV and DMA were used for plant treatment for 24 h. Total arsenic and arsenic speciation in xylem sap was analysed including a metabolite profiling under arsenate stress. Produced xylem sap was quantified and absolute arsenic transported was determined. AsV exposure has a significant impact on the metabolite profile of xylem sap. Four m/z values corresponding to four compounds were up regulated, one compound down regulated by arsenate exposure. The compound down regulated was identified to be isoleucine. Furthermore, arsenate has a significant influence on sap production, leading to a reduction of up to 96 % sap production when plants are exposed to 1000 μg kg-1 arsenate. No difference to control plants was observed when plants were exposed to 1000 μg kg-1 DMA. Absolute arsenic amount in xylem sap was the lowest at high arsenate exposure. These results show that AsV has a significant impact on the production and metabolite profile of xylem sap. The physiological importance of isoleucine needs further attention.

  16. Growth of strain SES-3 with arsenate and other diverse electron acceptors

    Science.gov (United States)

    Laverman, A.M.; Blum, J.S.; Schaefer, J.K.; Phillips, E.J.P.; Lovley, D.R.; Oremland, R.S.

    1995-01-01

    The selenate-respiring bacterial strain SES-3 was able to use a variety of inorganic electron acceptors to sustain growth. SES-3 grew with the reduction of arsenate to arsenite, Fe(III) to Fe(II), or thiosulfate to sulfide. It also grew in medium in which elemental sulfur, Mn(IV), nitrite, trimethylamine N-oxide, or fumarate was provided as an electron acceptor. Growth on oxygen was microaerophilic. There was no growth with arsenite or chromate. Washed suspensions of cells grown on selenate or nitrate had a constitutive ability to reduce arsenate but were unable to reduce arsenite. These results suggest that strain SES-3 may occupy a niche as an environmental opportunist by being able to take advantage of a diversity of electron acceptors.

  17. Quantitative trace-level speciation of arsenite and arsenate in drinking water by ion chromatography.

    Science.gov (United States)

    Johnson, Rebecca L; Aldstad, Joseph H

    2002-10-01

    We describe an improved method for the determination of inorganic arsenic in drinking water. The method is based on comprehensive optimization of the anion-exchange ion chromatographic (IC) separation of arsenite and arsenate with post-column generation and detection of the arsenate-molybdate heteropoly acid (AMHPA) complex ion. The arsenite capacity factor was improved from 0.081 to 0.13 by using a mobile phase (2.0 mL min(-1)) composed of 2.5 mM Na2CO3 and 0.91 mM NaHCO3 (pH 10.5). A post-column photo-oxidation reactor (2.5 m x 0.7 mm) was optimized (0.37 microM potassium persulfate at 0.50 mL min(-1)) such that arsenite was converted to arsenate with 99.8 +/- 4.2% efficiency. Multi-variate optimization of the complexation reaction conditions yielded the following levels: 1.3 mM ammonium molybdate, 7.7 mM ascorbic acid, 0.48 M nitric acid, 0.17 mM potassium antimony tartrate, and 1.0% (v/v) glycerol. A long-path length flow cell (Teflon AF, 100-cm) was used to measure the absorption of the AMHPA complex (818 +/- 2 nm). Figures of merit for arsenite/arsenate include: limit of detection (1.6/0.40 microg L(-1)): standard error in absorbance (5.1 x 10(-3)/3.5 x 10(-3)); and sensitivity (2.9 x 10(-3)/2.2 x 10(-3) absorbance units per ppb). Successful application of the method to fortified surface and ground waters (100 microL samples) is also described. PMID:12430600

  18. Arsenate Adsorption Mechanism on Nano-ball Allophane by Langmuir Adsorption Equation

    Directory of Open Access Journals (Sweden)

    Elvis Anup Shukla

    2011-12-01

    Full Text Available Arsenic is considered as the synonym of death. High toxicity of arsenic in nature is a worldwide problem and often referred to as 20th -21st century calamity. High arsenic concentration has been reported recently from USA, China, Chile, Bangladesh, Taiwan, Mexico, Argentina, Poland, Canada, Hungry, Japan and India. Among all the countries Bangladesh and West Bengal of India are at the high risk. Thus arsenic disposal became an important task. In the present study an attempt is made to study the adsorption of toxic arsenic on allophanes.The adsorption of arsenate on a low Si/Al ratio allophane (KyP was found to be very effective in reducing the amount of arsenic below the toxic level. The examination of adsorption isotherm of arsenate on allophane by Langmuir theory indicated that arsenate adsorption increased with the increasing bulk solution concentration. The observed increase in the pH can be attributed to the ligand exchange on allophane. Aluminol groups, Al-OH or Al-OH2, on allophane are responsible for the adsorption in soil.

  19. [Occurrence Characteristics of Pyrene and Arsenate and Their Interaction in Pteris vittata L].

    Science.gov (United States)

    Zhang, Yu-xiu; Ma, Xu; Liao, Xiao-yong; Yan, Xiu-lan; Ma, Dong; Gong, Xue-gang

    2015-12-01

    Pteris vittata L. can absorb and accumulate high arsenic levels in soil. To clarify the occurrence characteristics of pyrene (PYR) and arsenate (As) as well as their interaction in P. vittata L., the hosting and distribution rules of PYR were determined via two-photon laser scanning confocal microscopy (TPLSCM). The results showed that PYR addition resulted in obviously lower concentrations of total As in various parts of P. vittata, with a largest decrease of about 35% in the leaves and stem, and 20. 5% in the roots. PYR addition could also decrease the proportion of trivalent arsenic and increased that of pentavalent arsenate in different parts of P. vittata. The concentrations of trivalent and pentavalent arsenic in the leaves of P. vittata showed the largest decrement, which were 42.2% and 32.49%, respectively. Arsenate addition increased the accumulation of PYR in the root and stem of P. vittata by 9.8 µg and 139 ng per plant, respectively, while no obvious influence was found on the PYR in the leaves. Pyrene mainly attached to the cell membrane and other membrane structure such as nuclear membrane and organelle membrane, and there was less pyrene in the cytoplasm. There was little PYR in the phloem and cortex in the stem as well as palisade tissue and spongy tissue in leaves. PMID:27012002

  20. Arsenate Removal: Comparison of FSM-16 with Low Cost Modified Rice Husk

    International Nuclear Information System (INIS)

    The recently discovered meso porous molecular sieve FSM-16 was tested as an absorbent for arsenic (V) sorption from aqueous solutions. Its adsorption behavior was evaluated and compared with a low cost sorbent prepared from available agroresidue, rice husk, (boiled with 5% KOH followed by 10 % HCl). Factors affecting sorption of arsenate ions by the two sorbents (e.g., porosity, surface area of the sorbent, equilibrium time, adsorption rate, ph and temperature) were studied using ICP-MS for analysis. The data of adsorption of the two systems were described according to the S-Langmuir type according to the initial slope. The monolayer coverage was 92 and 68 mg/g for FSM-16 and modified rice husk (MRH),respectively, due to the silica content of the former is higher than the latter. The thermodynamic parameters were evaluated and indicated that this adsorption is endothermic process.It was found that the adsorptive capacity for arsenate using MRH represents 75% of that FSM-16. Therefore, the MRH is useful in the removal of arsenate ions due to its low cost, availability, and its good efficiency in this application and no need to be regenerated

  1. Respiratory System

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    8.1 Respiratory failure2007204 Comparison of the effects of BiPAP ventilation combined with lung recruitment maneuvers and low tidal volume A/C ventilation in patients with acute respiratory distress syndrome. WANG Xiaozhi(王晓芝),et al. Dept Respir & Intensive Care Unit, Binzhou Med Coll, Binzhou 256603. Chin J Tuberc Respir Dis 2007;30(1):44-47. Objective To compare the effects of BiPAP ventilation combined with lung recruitment maneuvers(LRM) with low tidal volume A/C ventilation in patients with acute respiratory distress syndrome (ARDS). Methods A prospective, randomized comparison of BiPAP mechanical ventilation combined with lung recruitment maneuvers(test group) with low tidal volume A/C ventilation (control group) was conducted in 28 patients with ARDS. FiO2/PaO2 ratio, respiratory system compliance(Cs), central venous pressure (CVP), duration of ventilation support were recorded at 0 h, 48 h and 72 h separately. The ventilation associated lung injury and mortality at 28 d were also recorded. Results The FiO2/PaO2 ratio were (298±16) and (309±16) cm H2O, Cs were (38.4±2.2) and (42.0±1.3) ml/cm H2O, CVP were (13.8±0.8) and (11.6±0.7) cm H2O in the test group at 48 h and 72 h separately. In the control group, FiO2/PaO2 ratio were (212±12) and (246±17) cm H2O, Cs were (29.5±1.3) and (29.0±1.0) ml/cm H2O, CVP were 18.6±1.1 and (16.8±1.0) cm H2O. The results were better in the test group as compared with the control group (t=10.03-29. 68, all P<0.01). The duration of ventilation support in the test group was shorter than the control group [(14±3) d vs (19±3)d, t=4.80, P<0.01]. The mortality in 28 d and ventilation associated lung injury were similar in the two groups. Conclusion The results show that combination of LRM with BiPAP mode ventilation, as compared with the control group, contributes to the improved FiO2/PaO2 ratio, pulmonary compliance, stable homodynamic and shorter duration of ventilation support in patients with ARDs.

  2. Sodium arsenate induce changes in fatty acids profiles and oxidative damage in kidney of rats.

    Science.gov (United States)

    Kharroubi, Wafa; Dhibi, Madiha; Mekni, Manel; Haouas, Zohra; Chreif, Imed; Neffati, Fadoua; Hammami, Mohamed; Sakly, Rachid

    2014-10-01

    Six groups of rats (n = 10 per group) were exposed to 1 and 10 mg/l of sodium arsenate for 45 and 90 days. Kidneys from treated groups exposed to arsenic showed higher levels of trans isomers of oleic and linoleic acids as trans C181n-9, trans C18:1n-11, and trans C18:2n-6 isomers. However, a significant decrease in eicosenoic (C20:1n-9) and arachidonic (C20:4n-6) acids were observed in treated rats. Moreover, the "Δ5 desaturase index" and the saturated/polyunsaturated fatty acids ratio were increased. There was a significant increase in the level of malondialdehyde at 10 mg/l of treatment and in the amount of conjugated dienes after 90 days (p < 0.05). Significant kidney damage was observed at 10 mg/l by increase of plasma marker enzymes. Histological studies on the ultrastructure changes of kidney supported the toxic effect of arsenate exposure. Arsenate intoxication activates significantly the superoxide dismutase at 10 mg/l for 90 days, whereas the catalase activity was markedly inhibited in all treated groups (p < 0.05). In addition, glutathione peroxidase activity was significantly increased at 45 days and dramatically declined after 90 days at 10 mg/l (p < 0.05). A significant increase in the level of glutathione was marked for the groups treated for 45 and 90 days at 1 mg/l followed by a significant decrease for rats exposed to 10 mg/l for 90 days. An increase in the level of protein carbonyl was observed in all treated groups (p < 0.05). In conclusion, the present study provides evidence for a direct effect of arsenate on fatty acid (FA) metabolism which concerns the synthesis pathway of n-6 polyunsaturated fatty acids and leads to an increase in the trans FAs isomers. Therefore, FA-induced arsenate kidney damage could contribute to trigger kidney cancer. PMID:24920263

  3. Lungs and Respiratory System

    Science.gov (United States)

    ... to Know About Zika & Pregnancy Lungs and Respiratory System KidsHealth > For Parents > Lungs and Respiratory System Print ... have taken at least 600 million breaths. Respiratory System Basics All of this breathing couldn't happen ...

  4. Respiratory Issues in OI

    Science.gov (United States)

    ... delivery, and other respiratory disorders may lead to respiratory failure and death particularly in people with OI Type ... have OI. It is a sobering fact that respiratory failure is the leading cause of death for people ...

  5. Identification, Characterization, and Classification of Genes Encoding Perchlorate Reductase

    OpenAIRE

    Bender, Kelly S.; Shang, Ching; Chakraborty, Romy; Belchik, Sara M.; Coates, John D.; Achenbach, Laurie A.

    2005-01-01

    The reduction of perchlorate to chlorite, the first enzymatic step in the bacterial reduction of perchlorate, is catalyzed by perchlorate reductase. The genes encoding perchlorate reductase (pcrABCD) in two Dechloromonas species were characterized. Sequence analysis of the pcrAB gene products revealed similarity to α- and β-subunits of microbial nitrate reductase, selenate reductase, dimethyl sulfide dehydrogenase, ethylbenzene dehydrogenase, and chlorate reductase, all of which are type II m...

  6. Adsorption kinetic of arsenates as water pollutant on iron, manganese and iron-manganese-modified clinoptilolite-rich tuffs

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez-Cedillo, M.J. [Instituto Nacional de Investigaciones Nucleares, Departamento de Quimica, A.P. 18-1027, Col, Escandon, Del, Miguel Hidalgo, C.P. 11801 Mexico, D.F. (Mexico); Universidad Autonoma del Estado de Mexico, Facultad de Quimica, Paseo Colon y Paseo Tollocan s/n, Toluca (Mexico); Olguin, M.T. [Instituto Nacional de Investigaciones Nucleares, Departamento de Quimica, A.P. 18-1027, Col, Escandon, Del, Miguel Hidalgo, C.P. 11801 Mexico, D.F. (Mexico)], E-mail: mog@nuclear.inin.mx; Fall, Ch. [Centro Interamericano de Recursos del Agua, CIRA, km 14.5 de la Carretera Toluca - Ixtlahuaca, Unidad San Cayetano, Estado de Mexico (Mexico)

    2009-04-30

    Arsenate adsorption from aqueous solutions onto clinoptilolite-heulandite rich tuffs modified with iron or manganese or a mixture of both iron and manganese in this work was investigated. A kinetic model was considered to describe the arsenates adsorption on each zeolitic material. The modified clinoptilolite-heulandite rich tuffs were characterized by scanning electron microscopy and X-ray diffraction analysis. The elemental composition and the specific surface area of the zeolitic material were also determined. The arsenate adsorption by the modified zeolites was carried on in a batch system considering a contact time from 5 min to 24 h for the kinetic experimentation. The arsenic was detected by atomic absorption spectrometer using a hydride generator. The kinetics of the arsenate adsorption processes were described by the pseudo-second-order model and the obtained parameter k varies from 0.15 to 5.66 {mu}g/gh. In general, the results suggested that the kinetic adsorption of arsenates on the modified clinoptilolite-rich tuffs depend of the metallic specie that modified the surface characteristics of the zeolitic material, the chemical nature of the metal as well as the association between different metallic chemical species in the zeolitic surface.

  7. Sepiapterin Reductase Deficiency: Mimic of Cerebral Palsy

    OpenAIRE

    J Gordon Millichap

    2012-01-01

    Researchers at University of California at San Diego, and 22 other US national and international centers studied the clinical, biochemical, and molecular findings in a cohort of 38 patients with sepiapterin reductase deficiency (SRD).

  8. Multiple aldehyde reductases of human brain.

    Science.gov (United States)

    Hoffman, P L; Wermuth, B; von Wartburg, J P

    1980-01-01

    Human brain contains four forms of aldehyde reducing enzymes. One major activity, designated AR3, has properties indicating its identity with the NADPH-dependent aldehyde reductase, EC 1.1.1.2. The other major form of human brain enzyme, AR1, which is also NADPH-dependent, reduces both aldehyde and ketone-containing substrates, including vitamin K3 (menadione) and daunorubicin, a cancer chemotherapeutic agent. This enzyme is very sensitive to inhibition by the flavonoids quercitrin and quercetine, and may be analogous to a daunorubicin reductase previously described in liver of other species. One minor form of human brain aldehyde reductase, AR2, demonstrates substrate specificity and inhibitor sensitivity which suggest its similarity to aldose reductases found in lens and other tissues of many species. This enzyme, which can also use NADH as cofactor to some extent, is the most active in reducing the aldehyde derivatives of the biogenic amines. The fourth human brain enzyme ("SSA reductase") differs from the other forms in its ability to use NADH as well as or better than NADPH as cofactor, and in its molecular weight, which is nearly twice that of the other forms. It is quite specific for succinic semialdehyde (SSA) as substrate, and was found to be significantly inhibited only by quercetine and quercitrin. AR3 can also reduce SSA, and both enzymes may contribute to the production of gamma-hydroxybutyric acid in vivo. These results indicate that the human brain aldehyde reductases can play relatively specific physiologic roles. PMID:7424738

  9. Nitrogen and oxygen regulation of Bacillus subtilis nasDEF encoding NADH-dependent nitrite reductase by TnrA and ResDE.

    Science.gov (United States)

    Nakano, M M; Hoffmann, T; Zhu, Y; Jahn, D

    1998-10-01

    The nitrate and nitrite reductases of Bacillus subtilis have two different physiological functions. Under conditions of nitrogen limitation, these enzymes catalyze the reduction of nitrate via nitrite to ammonia for the anabolic incorporation of nitrogen into biomolecules. They also function catabolically in anaerobic respiration, which involves the use of nitrate and nitrite as terminal electron acceptors. Two distinct nitrate reductases, encoded by narGHI and nasBC, function in anabolic and catabolic nitrogen metabolism, respectively. However, as reported herein, a single NADH-dependent, soluble nitrite reductase encoded by the nasDE genes is required for both catabolic and anabolic processes. The nasDE genes, together with nasBC (encoding assimilatory nitrate reductase) and nasF (required for nitrite reductase siroheme cofactor formation), constitute the nas operon. Data presented show that transcription of nasDEF is driven not only by the previously characterized nas operon promoter but also from an internal promoter residing between the nasC and nasD genes. Transcription from both promoters is activated by nitrogen limitation during aerobic growth by the nitrogen regulator, TnrA. However, under conditions of oxygen limitation, nasDEF expression and nitrite reductase activity were significantly induced. Anaerobic induction of nasDEF required the ResDE two-component regulatory system and the presence of nitrite, indicating partial coregulation of NasDEF with the respiratory nitrate reductase NarGHI during nitrate respiration. PMID:9765565

  10. Biotransformation of arsenate to the tetramethylarsonium ion in the marine polychaetes Nereis diversicolor and Nereis virens.

    Science.gov (United States)

    Geiszinger, Anita E; Goessler, Walter; Francesconi, Kevin A

    2002-07-01

    Arsenic compounds in aqueous extracts of the marine polychaetes Nereis diversicolor and Nereis virens were determined by HPLC-ICP-MS. Both polychaetes contained most of their water-soluble arsenic as arsenobetaine (approximately 60%), and the tetramethylarsonium ion was also a significant arsenic constituent (approximately 20% in N. diversicolor and approximately 30% in N. virens). Trimethylarsoniopropionate and arsenosugars were present in the Nereis species as minor constituents, and traces of arsenocholine, trimethylarsine oxide, and arsenate were also detected. When N. diversicolor and N. virens were exposed in laboratory experiments to different concentrations of arsenate in seawater (10, 50, 100, 500, and 1000 microg of As L(-1)), both species accumulated arsenic in a dose-dependent manner. Atthe highest exposure level, they achieved mean arsenic concentrations (dry mass) of approximately 70 mg of As kg(-1) (N. virens) and 90 mg of As kg(-1) (N. diversicolor), which represented about a 5-fold increase when compared with the control animals. The arsenic taken up by the polychaetes was readily methylated, and the major metabolite was the tetramethylarsonium ion (up to approximately 85% of the accumulated arsenic). Two other products of arsenic methylation, methylarsonate and trimethylarsine oxide, were also produced to a small extent; however, dimethylarsinate, another likely intermediate in the formation of the tetramethylarsonium ion, could not be detected in these experiments. The remaining accumulated arsenic was present as unchanged arsenate. This is the first report of significant biomethylation of arsenic to the tetramethyl stage and provides a ready explanation for the widespread occurrence of tetramethylarsonium ion in marine animals. PMID:12144266

  11. Arsenic accumulation by the aquatic fern Azolla: comparison of arsenate uptake, speciation and efflux by A. caroliniana and A. filiculoides.

    Science.gov (United States)

    Zhang, Xin; Lin, Ai-Jun; Zhao, Fang-Jie; Xu, Guo-Zhong; Duan, Gui-Lan; Zhu, Yong-Guan

    2008-12-01

    This study investigates As accumulation and tolerance of the aquatic fern Azolla. Fifty strains of Azolla showed a large variation in As accumulation. The highest- and lowest-accumulating ferns among the 50 strains were chosen for further investigations. Azolla caroliniana accumulated two times more As than Azolla filiculoides owing to a higher influx velocity for arsenate. A. filiculoides was more resistant to external arsenate due to a lower uptake. Both strains showed a similar degree of tolerance to internal As. Arsenate and arsenite were the dominant As species in both Azolla strains, with methylated As species accounting for Azolla in paddy fields to reduce As transfer from soil and water to rice should be further evaluated. PMID:18457908

  12. Middle East Respiratory Syndrome

    Centers for Disease Control (CDC) Podcasts

    2014-07-07

    This podcast discusses Middle East Respiratory Syndrome, or MERS, a viral respiratory illness caused by Middle East Respiratory Syndrome Coronavirus—MERS-CoV.  Created: 7/7/2014 by National Center for Immunization and Respiratory Diseases (NCIRD).   Date Released: 7/7/2014.

  13. New Functional Sulfide Oxidase-Oxygen Reductase Supercomplex in the Membrane of the Hyperthermophilic Bacterium Aquifex aeolicus*

    OpenAIRE

    Prunetti, Laurence; Infossi, Pascale; Brugna, Myriam; Ebel, Christine; Giudici-Orticoni, Marie-Thérèse; Guiral, Marianne

    2010-01-01

    Aquifex aeolicus, a hyperthermophilic and microaerophilic bacterium, obtains energy for growth from inorganic compounds alone. It was previously proposed that one of the respiratory pathways in this organism consists of the electron transfer from hydrogen sulfide (H2S) to molecular oxygen. H2S is oxidized by the sulfide quinone reductase, a membrane-bound flavoenzyme, which reduces the quinone pool. We have purified and characterized a novel membrane-bound multienzyme supercomplex that brings...

  14. Spectroscopic and Kinetic Studies of Nor1, a Cytochrome P450 Nitric Oxide Reductase From the Fungal Pathogen Histoplasma capsulatum†

    OpenAIRE

    Chao, Lily Y.; Rine, Jasper; Marletta, Michael A

    2008-01-01

    The fungal respiratory pathogen Histoplasma capsulatum evades the innate immune response and colonizes macrophages during infection. Although macrophage production of the antimicrobial effector nitric oxide (NO) restricts H. capsulatum growth, the pathogen is able to establish a persistent infection. H. capsulatum contains a P450 nitric oxide reductase homologue (NOR1) that may be important for detoxifying NO during infection. To characterize the activity of this putative P450 enzyme, a 404 a...

  15. Bioaccumulation Dynamics of Arsenate at the Base of Aquatic Food Webs.

    Science.gov (United States)

    Lopez, Adeline R; Hesterberg, Dean R; Funk, David H; Buchwalter, David B

    2016-06-21

    Periphyton is an important food source at the base of freshwater ecosystems that tends to bioconcentrate trace elements making them trophically available. The potential for arsenic-a trace element of particular concern due to its widespread occurrence, toxicity, and carcinogenicity-to bioconcentrate in periphyton and thus be available to benthic grazers is less well characterized. To better understand arsenate bioaccumulation dynamics in lotic food webs, we used a radiotracer approach to characterize accumulation in periphyton and subsequent trophic transfer to benthic grazers. Periphyton bioconcentrated As between 3,200-9,700-fold (dry weight) over 8 days without reaching steady state, suggesting that periphyton is a major sink for arsenate. However, As-enriched periphyton as a food source for the mayfly Neocloeon triangulifer resulted in negligible As accumulation in a full lifecycle exposure. Additional studies estimate dietary assimilation efficiency in several primary consumers ranging from 22% in the mayfly N. triangulifer to 75% in the mayfly Isonychia sp. X-ray fluorescence mapping revealed that As was predominantly associated with iron oxides in periphyton. We speculate that As adsorption to Fe in periphyton may play a role in reducing dietary bioavailability. Together, these results suggest that trophic movement of As in lotic food webs is relatively low, though species differences in bioaccumulation patterns are important. PMID:27223406

  16. Effects of Chronic Exposure to Sodium Arsenate on Kidney of Rats

    Directory of Open Access Journals (Sweden)

    Namdar Yousofvand

    2015-09-01

    Full Text Available Background: In the present study, histopathological effects of chronic exposure to sodium arsenate in drinkable water were studied on a quantity of organs of rat. Methods: Rats were divided into two groups, group I; served as control group, were main-tained on deionized drinkable water for 2 months, and group II; the study group were given 60 g/ml of sodium arsenate in deionized drinkable water for 2 months. Blood and urine samples from two groups of animals were collected under anesthesia and the animals were sacrificed under deep anesthesia (a-chloralose, 100 mg/kg, I.P. Their kidney, liver, aorta, and heart were dissected out and cleaned of surrounding connective tissue. The organs were kept in formaldehyde (10% for histopathologic examination. Serum and urine samples from two groups were collected and analyzed for arsenic level. Total quantity of arsenic in serum and urine of animal was measured through graphic furnace atomic absorption spectrometry (GF-AAS. Results:Examination with light microscopy did not show any visible structural changes in the aorta, myocardium, and liver of chronic arsenic treated animals.However, a significant effect was observed in the kidneys of chronic arsenic treated rats showing distinct changes in proxi-mal tubular cells. There was high concentration of arsenic in serum and urine of arsenic ex-posed animals (group II significantly (P<0.001. Conclusion:Swollen tubular cells in histopathologic study of kidney may suggest toxic effects of arsenic in the body.

  17. Developmental consequences of in utero sodium arsenate exposure in mice with folate transport deficiencies

    International Nuclear Information System (INIS)

    Previous studies have demonstrated that mice lacking a functional folate binding protein 2 gene (Folbp2-/-) were significantly more sensitive to in utero arsenic exposure than were the wild-type mice similarly exposed. When these mice were fed a folate-deficient diet, the embryotoxic effect of arsenate was further exacerbated. Contrary to expectations, studies on 24-h urinary speciation of sodium arsenate did not demonstrate any significant difference in arsenic biotransformation between Folbp2-/- and Folbp2+/+ mice. To better understand the influence of folate pathway genes on arsenic embryotoxicity, the present investigation utilized transgenic mice with disrupted folate binding protein 1 (Folbp1) and reduced folate carrier (RFC) genes. Because complete inactivation of Folbp1 and RFC genes results in embryonic lethality, we used heterozygous animals. Overall, no RFC genotype-related differences in embryonic susceptibility to arsenic exposure were observed. Embryonic lethality and neural tube defect (NTD) frequency in Folbp1 mice was dose-dependent and differed from the RFC mice; however, no genotype-related differences were observed. The RFC heterozygotes tended to have higher plasma levels of S-adenosylhomocysteine (SAH) than did the wild-type controls, although this effect was not robust. It is concluded that genetic modifications at the Folbp1 and RFC loci confers no particular sensitivity to arsenic toxicity compared to wild-type controls, thus disproving the working hypothesis that decreased methylating capacity of the genetically modified mice would put them at increased risk for arsenic-induced reproductive toxicity

  18. Structural and mechanistic insights on nitrate reductases.

    Science.gov (United States)

    Coelho, Catarina; Romão, Maria João

    2015-12-01

    Nitrate reductases (NR) belong to the DMSO reductase family of Mo-containing enzymes and perform key roles in the metabolism of the nitrogen cycle, reducing nitrate to nitrite. Due to variable cell location, structure and function, they have been divided into periplasmic (Nap), cytoplasmic, and membrane-bound (Nar) nitrate reductases. The first crystal structure obtained for a NR was that of the monomeric NapA from Desulfovibrio desulfuricans in 1999. Since then several new crystal structures were solved providing novel insights that led to the revision of the commonly accepted reaction mechanism for periplasmic nitrate reductases. The two crystal structures available for the NarGHI protein are from the same organism (Escherichia coli) and the combination with electrochemical and spectroscopic studies also lead to the proposal of a reaction mechanism for this group of enzymes. Here we present an overview on the current advances in structural and functional aspects of bacterial nitrate reductases, focusing on the mechanistic implications drawn from the crystallographic data. PMID:26362109

  19. Facile synthesis of size-tunable gold nanoparticles by pomegranate (Punica granatum) leaf extract: Applications in arsenate sensing

    International Nuclear Information System (INIS)

    Highlights: ► Pomegranate leaf extracts mediated rapid gold nanoparticle (AuNP) synthesis. ► The phyto-inspired AuNPs were size-tuned and characterized. ► The reducing and capping agents in the extract were identified. ► The nanoparticles reacted specifically with arsenate (V) ions. - Abstract: When pomegranate leaf extracts were incubated with chloroauric acid (HAuCl4), gold nanoparticles (AuNPs) were synthesized. These were characterized by a variety of techniques. With an increasing content of the leaf extract, a gradual decrease in size and an increase in monodispersity were observed. Transmission electron microscope (TEM) images showed that the phyto-fabricated AuNPs were surrounded by an amorphous layer. Gallic acid in the extract mediated the reduction and a natural decapeptide capped the nanostructures. Blocking of thiol groups in the decapeptide cysteine residues caused the nanoparticles to aggregate. On interaction with arsenate (V) ions, the UV–vis spectra of the nanoparticles showed a decrease in intensity and a red-shift. Energy dispersive spectra confirmed the presence of arsenate associated with the AuNPs. Thus, by using these AuNPs, a method for sensing the toxic arsenate ions could be developed

  20. Facile synthesis of size-tunable gold nanoparticles by pomegranate (Punica granatum) leaf extract: Applications in arsenate sensing

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Ashit; Mahajan, Ketakee; Bankar, Ashok [Institute of Bioinformatics and Biotechnology, University of Pune, Pune 411007 (India); Srikanth, Rapole [Proteomics Laboratory, National Centre for Cell Science, Pune 411007 (India); Kumar, Ameeta Ravi [Institute of Bioinformatics and Biotechnology, University of Pune, Pune 411007 (India); Gosavi, Suresh, E-mail: swg@physics.unipune.ac.in [Department of Physics, University of Pune, Pune 411007 (India); Centre for Sensor Studies, University of Pune, Pune 411007 (India); Zinjarde, Smita, E-mail: smita@unipune.ac.in [Institute of Bioinformatics and Biotechnology, University of Pune, Pune 411007 (India); Centre for Sensor Studies, University of Pune, Pune 411007 (India)

    2013-03-15

    Highlights: ► Pomegranate leaf extracts mediated rapid gold nanoparticle (AuNP) synthesis. ► The phyto-inspired AuNPs were size-tuned and characterized. ► The reducing and capping agents in the extract were identified. ► The nanoparticles reacted specifically with arsenate (V) ions. - Abstract: When pomegranate leaf extracts were incubated with chloroauric acid (HAuCl{sub 4}), gold nanoparticles (AuNPs) were synthesized. These were characterized by a variety of techniques. With an increasing content of the leaf extract, a gradual decrease in size and an increase in monodispersity were observed. Transmission electron microscope (TEM) images showed that the phyto-fabricated AuNPs were surrounded by an amorphous layer. Gallic acid in the extract mediated the reduction and a natural decapeptide capped the nanostructures. Blocking of thiol groups in the decapeptide cysteine residues caused the nanoparticles to aggregate. On interaction with arsenate (V) ions, the UV–vis spectra of the nanoparticles showed a decrease in intensity and a red-shift. Energy dispersive spectra confirmed the presence of arsenate associated with the AuNPs. Thus, by using these AuNPs, a method for sensing the toxic arsenate ions could be developed.

  1. TISSUE DISTRIBUTION OF INORGANIC ARSENIC (AS) AND ITS METHYLATED METABOLITES IN MICE FOLLOWING ORAL ADMINISTRATION OF ARSENATE (ASV)

    Science.gov (United States)

    TISSUE DISTRIBUTION OF INORGANIC ARSENIC (iAs) AND ITS METHYLATED METABOLITES IN MICE FOLLOWING ORAL ADMINISTRATION OF ARSENATE (AsV). E M Kenyon1, L M Del Razo2, and M F Hughes1. 1NHEERL, ORD, US EPA, RTP, NC, USA; 2CINVESTAV-IPN, Mexico City, Mexico.The relationship o...

  2. Arsenic accumulation by the aquatic fern Azolla: Comparison of arsenate uptake, speciation and efflux by A. caroliniana and A. filiculoides

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Xin [State Key Lab of Urban and ONAL Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China); Lin Aijun [Department of Environmental Science and Engineering, Beijing University of Chemical Technology, Beijing 100029 (China); Zhao Fangjie [Soil Science Department, Rothamsted Research, Hertfordshire AL5 2JQ (United Kingdom); Xu Guozhong [Agricultural Ecology Institute, Fujian Academy of Agricultural Sciences, Fuzhou 350013 (China); Duan Guilan [State Key Lab of Urban and ONAL Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China); Zhu Yongguan [State Key Lab of Urban and ONAL Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, 18 Shuangqing Road, Beijing 100085 (China); Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361003 (China)], E-mail: ygzhu@rcees.ac.cn

    2008-12-15

    This study investigates As accumulation and tolerance of the aquatic fern Azolla. Fifty strains of Azolla showed a large variation in As accumulation. The highest- and lowest-accumulating ferns among the 50 strains were chosen for further investigations. Azolla caroliniana accumulated two times more As than Azolla filiculoides owing to a higher influx velocity for arsenate. A. filiculoides was more resistant to external arsenate due to a lower uptake. Both strains showed a similar degree of tolerance to internal As. Arsenate and arsenite were the dominant As species in both Azolla strains, with methlyated As species accounting for <5% of the total As. A. filiculoides had a higher proportion of arsenite than A. caroliniana. Both strains effluxed more arsenate than arsenite, and the amount of As efflux was proportional to the amount of As accumulation. The potential of growing Azolla in paddy fields to reduce As transfer from soil and water to rice should be further evaluated. - Arsenic accumulation and efflux differ between strains of the aquatic fern Azolla.

  3. Genome wide analysis of DNA methylation and gene expression changes in the mouse lung following subchronic arsenate exposure

    Science.gov (United States)

    Alterations in DNA methylation have been proposed as a mechanism for the complex toxicological effects of arsenic. In this study, whole genome DNA methylation and gene expression changes were evaluated in lungs from female mice exposed for 90 days to 50 ppm arsenate (As) in drink...

  4. A green sorbent of esterified egg-shell membrane for highly selective uptake of arsenate and speciation of inorganic arsenic.

    Science.gov (United States)

    Chen, Ming-Li; Gu, Cui-Bo; Yang, Ting; Sun, Yan; Wang, Jian-Hua

    2013-11-15

    Egg-shell membrane (ESM) is a promising adsorbent for heavy metal uptake. However, carboxylic groups on ESM surface barrier arsenic adsorption. Herein, ESM is modified by esterification and the methyl esterified egg-shell membrane (MESM) possesses positive charge within pH 1-9. As a novel green sorbent material, MESM exhibits 200-fold improvement on sorption capacity of arsenate with respect to bare ESM. It presents an ultra-high selectivity of 256:1 toward arsenate against arsenite. At pH 6, 100% sorption efficiency is achieved for 2 μg L(-1) As(V) by 10 mg MESM, while virtually no adsorption of As(III) is observed. This provides great potential for selective sorption of arsenate in the presence of arsenite. By loading 4.0 mL sample within 0.05-5.00 μg L(-1) As(V) followed by elution with 300 μL HCl (1.5 mol L(-1)), a detection limit of 15 ng L(-1) is obtained along with a RSD of 3.5% at 0.5 μg L(-1). Total inorganic arsenic is achieved by converting As(III) to As(V) and following the same sorption process. This procedure is applied for arsenate determination and inorganic arsenic speciation in Hijiki and water samples. The results are confirmed by graphite furnace atomic absorption spectrometry and spiking recovery. PMID:24148462

  5. Lead and Arsenic Uptake by Carrots Grown on Five Orchard Soils With History of Lead Arsenate Used

    Science.gov (United States)

    Lead arsenate was used to control codling moth in apple and plum orchards from 1900 to 1960. Consequently, many orchard soils are contaminated with lead (Pb) and arsenic (As). Some of these lands are being used for urban development and vegetable crop production. Both soil Pb and As have become i...

  6. Effects of meso-2,3-dimercaptosuccinic acid (DMSA) on the teratogenicity of sodium arsenate in mice

    Energy Technology Data Exchange (ETDEWEB)

    Bosque, M.A.; Domingo, J.L.; Llobet, J.M. (Univ. of Barcelona, Reus (Spain)); Corbella, J. (Univ. of Barcelona (Spain))

    1991-11-01

    Although the effects of arsenic on mammalian development are now well established, very few data on the protective activity of different chelators against embryotoxicity and teratogenicity of arsenic are available. Chelating agents may interact with teratogen metals to augment or ameliorate their actions. Researchers demonstrated that a single dose of 2,3-dimercaptopropanol (BAL) was capable of affording a degree of protection to arsenate exposed fetal mice. Subcutaneous treatment with 50 mg/kg of BAL 4 hr after arsenate reduced the frequency or severity of malformations compared with the effects of arsenate alone. However, BAL has several drawbacks. In recent years dimercaptosuccinic acid (DMSA) is receiving growing attention in the USA and Western Europe. Results of a number of different investigations in rodents have led to the conclusion that DMSA is much less toxic than BAL. Moreover, DMSA has been reported to be effective in inducing arsenic excretion. In the present study, the protective effects of DMSA in alleviating the embryotoxic and teratogenic effects of sodium arsenate were evaluated in mice.

  7. Arsenate and Arsenite Sorption on Magnetite: Relations to Groundwater Arsenic Treatment Using Zerovalent Iron and Natural Attenuation

    Science.gov (United States)

    Magnetite (Fe3O4) is a zerovalent iron corrosion product; it is also formed in natural soil and sediment. Sorption of arsenate (As(V)) and arsenite (As(III)) on magnetite is an important process of arsenic removal from groundwater using zerovalent iron-based permeable reactive ba...

  8. 21 CFR 864.7375 - Glutathione reductase assay.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Glutathione reductase assay. 864.7375 Section 864... reductase assay. (a) Identification. A glutathione reductase assay is a device used to determine the... fluorescence and photometry. The results of this assay are used in the diagnosis of liver disease,...

  9. Characterization of the chlorate reductase from Pseudomonas chloritidismutans

    NARCIS (Netherlands)

    Wolterink, A.F.W.M.; Schiltz, E.; Hagedoorn, P.L.; Hagen, W.R.; Kengen, S.W.M.; Stams, A.J.M.

    2003-01-01

    A chlorate reductase has been purified from the chlorate-reducing strain Pseudomonas chloritidismutans. Comparison with the periplasmic (per)chlorate reductase of strain GR-1 showed that the cytoplasmic chlorate reductase of P. chloritidismutans reduced only chlorate and bromate. Differences were al

  10. Avian respiratory system disorders

    Science.gov (United States)

    Olsen, G.H.

    1989-01-01

    Diagnosing and treating respiratory diseases in avian species requires a basic knowledge about the anatomy and physiology of this system in birds. Differences between mammalian and avian respiratory system function, diagnosis, and treatment are highlighted.

  11. Acute respiratory distress syndrome

    Science.gov (United States)

    ... chap 33. Lee WL, Slutsky AS. Acute hypoxemic respiratory failure and ARDS. In: Broaddus VC, Mason RJ, Ernst JD, et al, eds. Murray and Nadel's Textbook of Respiratory Medicine . 6th ed. Philadelphia, PA: Elsevier Saunders; 2016: ...

  12. What Causes Respiratory Failure?

    Science.gov (United States)

    ... page from the NHLBI on Twitter. What Causes Respiratory Failure? Diseases and conditions that impair breathing can cause ... injure your lungs. Normal Lungs and Conditions Causing Respiratory Failure Figure A shows the location of the lungs, ...

  13. Acute respiratory distress syndrome

    Science.gov (United States)

    ... chap 33. Lee WL, Slutsky AS. Acute hypoxemic respiratory failure and ARDS. In: Broaddus VC, Mason RJ, Ernst ... A.M. Editorial team. Related MedlinePlus Health Topics Respiratory Failure Browse the Encyclopedia A.D.A.M., Inc. ...

  14. Lungs and Respiratory System

    Science.gov (United States)

    ... How Can I Help a Friend Who Cuts? Lungs and Respiratory System KidsHealth > For Teens > Lungs and ... you didn't breathe, you couldn't live. Lungs & Respiratory System Basics Each day we breathe about ...

  15. Respiratory Syncytial Virus

    Science.gov (United States)

    ... Things to Know About Zika & Pregnancy Respiratory Syncytial Virus KidsHealth > For Parents > Respiratory Syncytial Virus Print A A A Text Size What's in ... RSV When to Call the Doctor en español Virus respiratorio sincitial About RSV Respiratory syncytial (sin-SISH- ...

  16. Extraction of chromated copper arsenate from wood wastes using green solvent supercritical carbon dioxide

    International Nuclear Information System (INIS)

    To provide a green method to remove chromated copper arsenate (CCA) in the wood before its dumping, incineration, reuse or disposal, extraction of CCA from wood wastes using supercritical carbon dioxide (ScCO2) containing an organophosphorus reagent, Cyanex 302, was investigated. The majority of copper metal was removed using Cyanex 302 in supercritical fluid extraction (SFE). The order of extraction efficiency was found to be Cu >> As > Cr. Factors that affected SFE efficiencies, such as matrices, oxidation state of metal species [Cr(III), Cr(VI), As(III), and As(V)], and SFE pressure, were studied. Using this in situ chelation/SFE technique to remove leachable metals from the CCA-treated wood was found to significantly reduce the risk of leaching metals into the environment during storage, or waste disposal

  17. Characterization of adsorption of aqueous arsenite and arsenate onto charred dolomite in microcolumn systems.

    Science.gov (United States)

    Salameh, Yousef; Al-Muhtaseb, Ala'a H; Mousa, Hasan; Walker, Gavin M; Ahmad, Mohammad N M

    2014-01-01

    In this work, the removal of arsenite, As(III), and arsenate, As(V), from aqueous solutions onto thermally processed dolomite (charred dolomite) via microcolumn was evaluated. The effects of mass of adsorbent (0.5-2 g), initial arsenic concentration (50-2000 ppb) and particle size (dolomite in a microcolumn were investigated. It was found that the adsorption of As(V) and As(III) onto charred dolomite exhibited a characteristic 'S' shape. The adsorption capacity increased as the initial arsenic concentration increased. A slow decrease in the column adsorption capacity was noted as the particle size increased from>0.335 to 0.710-2.00 mm. For the binary system, the experimental data show that the adsorption of As(V) and As(III) was independent of both ions in solution. The experimental data obtained from the adsorption process were successfully correlated with the Thomas Model and Bed Depth Service Time Model. PMID:25244130

  18. Arsenite and arsenate removal from wastewater using cationic polymer-modified waste tyre rubber.

    Science.gov (United States)

    Imyim, Apichat; Sirithaweesit, Thitayati; Ruangpornvisuti, Vithaya

    2016-01-15

    Waste tyre rubber (WTR) granulate was modified with a cationic polymer, poly(3-acrylamidopropyl)trimethylammonium chloride (p(APTMACl)). The resulting WTR/p(APTMACl) was utilized for the adsorption of arsenite, As(III) and arsenate, As(V) from aqueous medium in both batch and column methods. The level of adsorption increased gradually with increasing monomer concentration and contact time. The adsorption behavior obeyed the Freundlich model, and the rate of adsorption could be predicted by employing the pseudo-second order model. In the column method, As(V) could be adsorbed onto the sorbent more effectively than As(III). Remarkable desorption of As(III) and As(V) (99 and 92%, respectively) from the adsorbent was achieved using 0.10 M HCl as eluent. An approach of evaluation of adsorption capacity uncertainty is proposed. PMID:26607568

  19. Dose dependent changes in 74As-arsenate metabolism of Flemish giant rabbits

    International Nuclear Information System (INIS)

    The metabolic handling of 74As-arsenate (As(V)) was studied in rabbits injected intraperitoneally (i.p) with increasing doses of As(V) (0.00 to 1.00 mgAs(V)/kg/day) over a period of 10 days. Plasma, packed cells, urine from the bladder and several tissues were analyzed for their 74As content and presence of 74As-As(V) metabolites 4 h after administration of 74As-As(V). 74As showed strong increases with increasing As(V) dose in nails and bone whereas in fat, thyroid and kidneys it decreased. Also with increasing As(V) dose, arsenate was less efficiently methylated to dimethylarsenic acid (DMA) and became more bound to insoluble tissue constituents. As a result 74As-DMA levels in tissues were systematically lower in the groups of rabbits receiving the higher doses, be it with a wide variation from one type of tissue to the other. The behaviour of 74As-monomethylarsonic acid (MMA) was different. The levels did not decrease significantly, occasionally even increased compared to the control group, indicating that especially the second methylation step is sensitive towards increasing doses of As(V). 74As-arsenite (As(III)), formed by in vivo reduction of As(V), reached maximal levels in the 0.25 mg As(V)/kg/day group as a result of the inhibited methylation. At doses >0.25 mg As(V)/kg/day the amount of 74As-As(V) increased especially in plasma, packed cells and the urine in the bladder, indicative for a less efficient reduction of As(V). (orig.)

  20. The Effect of Compression on the Annealing Behaviour of Neutron-Irradiated Potassium Dihydrogen Arsenate Crystals

    International Nuclear Information System (INIS)

    The annealing behaviour of As76 atoms (from (n, γ) reaction) and As74 atoms (from (n, 2n) reaction) in neutron (slow and fast) irradiated potassium dihydrogen arsenate crystals with and without compression has been studied. Several times recrystallized, A.R. grade potassium dihydrogen arsenate crystals sieved to 20-30 and 30-80 mesh size were used for irradiation in the BEPO reactor and for fast neutron irradiation. Thermal annealing was performed in a thermostatically controlled air oven. The compression of samples was carried out in sealed copper tubes either with or without liquid paraffin as medium. Applied pressure ranged up to 2000 atm. The distribution of radioactive arsenic atoms between tri- and pentavalent form was carried out either by paper electrophoresis in 0.01M sodium hydroxide solutions (for slow-neutron-irradiated samples) or by gravimetric method as magnesium pyroarsenate (for fast-neutron-irradiated samples). Paper strips were counted by an end-window G-M tube. The magnesium pyroarsenate samples were counted after dissolution in sulphuric acid by means of a liquid counter. It has been found that there is no essential differente in annealing behaviour of As74 and As76 atoms both without and with pressure treatment, when the paraffin oil is used as pressure transmitting medium. When irradiated samples are compressed without paraffin oil, there is an increase of the content of the pentavalent form of arsenic as long as the pressure is applied before the pseudo-plateau for the given temperature has been reached. The amount of the change does not depend on the value of pressure applied, once the threshold value has been applied. The effect has been explained in terms of defects produced by slipping of dislocation lines, caused by anisotropic compression, when the pressure is applied without the paraffin oil as medium. (author)

  1. Inhibition of NADH-ubiquinone reductase activity by N,N'-dicyclohexylcarbodiimide and correlation of this inhibition with the occurrence of energy-coupling site 1 in various organisms

    International Nuclear Information System (INIS)

    The NADH-ubiquinone reductase activity of the respiratory chains of several organisms was inhibited by the carboxyl-modifying reagent N,N'-dicyclohexylcarbodiimide (DCCD). This inhibition correlated with the presence of an energy-transducing site in this segment of the respiratory chain. Where the NADH-quinone reductase segment involved an energy-coupling site (e.g., in bovine heart and rat liver mitochondria, and in Paracoccus denitrificans, Escherichia coli, and Thermus thermophilus HB-8 membranes), DCCD acted as an inhibitor of ubiquinone reduction by NADH. By contrast, where energy-coupling site 1 was absent (e.g., in Saccharomyces cerevisiae mitochondria and BacilLus subtilis membranes), there was no inhibition of NADH-ubiquinone reductase activity by DCCD. In the bovine and P. denitrificans systems, DCCD inhibition was pseudo first order with respect to incubation time, and reaction order with respect to inhibitor concentration was close to unity, indicating that inhibition resulted from the binding of one inhibitor molecule per active unit of NADH-ubiquinone reductase. In the bovine NADH-ubiquinone reductase complex (complex I), [14C]DCCD was preferentially incorporated into two subunits of molecular weight 49,000 and 29,000. The time course of labeling of the 29,000 molecular weight subunit with [14C]DCCD paralleled the time course of inhibition of NADH-ubiquinone reductase activity

  2. Electron transport to periplasmic nitrate reductase (NapA) of Wolinella succinogenes is independent of a NapC protein.

    Science.gov (United States)

    Simon, Jörg; Sänger, Monica; Schuster, Stephan C; Gross, Roland

    2003-07-01

    The rumen bacterium Wolinella succinogenes grows by respiratory nitrate ammonification with formate as electron donor. Whereas the enzymology and coupling mechanism of nitrite respiration is well known, nitrate reduction to nitrite has not yet been examined. We report here that intact cells and cell fractions catalyse nitrate and chlorate reduction by reduced viologen dyes with high specific activities. A gene cluster encoding components of a putative periplasmic nitrate reductase system (napA, G, H, B, F, L, D) was sequenced. The napA gene was inactivated by inserting a kanamycin resistance gene cassette. The resulting mutant did not grow by nitrate respiration and did not reduce nitrate during growth by fumarate respiration, in contrast to the wild type. An antigen was detected in wild-type cells using an antiserum raised against the periplasmic nitrate reductase (NapA) from Paracoccus pantotrophus. This antigen was absent in the W. succinogenes napA mutant. It is concluded that the periplasmic nitrate reductase NapA is the only respiratory nitrate reductase in W. succinogenes, although a second nitrate-reducing enzyme is apparently induced in the napA mutant. The nap cluster of W. succinogenes lacks a napC gene whose product is thought to function in quinol oxidation and electron transfer to NapA in other bacteria. The W. succinogenes genome encodes two members of the NapC/NirT family, NrfH and FccC. Characterization of corresponding deletion mutants indicates that neither of these two proteins is required for nitrate respiration. A mutant lacking the genes encoding respiratory nitrite reductase (nrfHA) had wild-type properties with respect to nitrate respiration. A model of the electron transport chain of nitrate respiration is proposed in which one or more of the napF, G, H and L gene products mediate electron transport from menaquinol to the periplasmic NapAB complex. Inspection of the W. succinogenes genome sequence suggests that ammonia formation from

  3. Crystallization of mitochondrial rhodoquinol-fumarate reductase from the parasitic nematode Ascaris suum with the specific inhibitor flutolanil

    International Nuclear Information System (INIS)

    Rhodoquinol-fumarate reductase is a key enzyme in the anaerobic respiratory chain of adult A. suum mitochondria. Its crystallization in the presence of a mixture of octaethyleneglycol monododecyl ether and n-dodecyl-β-d-maltopyranoside in a form suitable for X-ray structure analysis is reported. In adult Ascaris suum (roundworm) mitochondrial membrane-bound complex II acts as a rhodoquinol-fumarate reductase, which is the reverse reaction to that of mammalian complex II (succinate-ubiquinone reductase). The adult A. suum rhodoquinol-fumarate reductase was crystallized in the presence of octaethyleneglycol monododecyl ether and n-dodecyl-β-d-maltopyranoside in a 3:2 weight ratio. The crystals belonged to the orthorhombic space group P212121, with unit-cell parameters a = 123.75, b = 129.08, c = 221.12 Å, and diffracted to 2.8 Å resolution using synchrotron radiation. The presence of two molecules in the asymmetric unit (120 kDa × 2) gives a crystal volume per protein mass (VM) of 3.6 Å3 Da−1

  4. Salinity Effects on the Biogeochemical Cycles of Sulfate, Arsenate, Nitrate, and Methane in Anoxic Sediments of Mono Lake and Searles Lake, California.

    Science.gov (United States)

    Kulp, T. R.; Hoeft, S. E.; Miller, L. G.; Oremland, R. S.

    2005-12-01

    Mono Lake and Searles Lake are two members of a chain of hypersaline and alkaline soda lakes that occur in closed basins along the arid eastern escarpment of the Sierra Nevada in California. These lakes are alkaline (pH = 9.8), highly saline, and As-rich due to hydrothermal input and evaporative concentration. Mono Lake is characterized by a salinity of 90 g/L and contains 200μM dissolved As. Searles Lake, a partially-dry residual playa, exhibits salt concentrations >300 g/L (near saturation) and 3.9 mM dissolved As. We utilized 35SO4 and 73As(V) as radioactive tracers to compare sulfate and arsenate [As(V)] reductase activities at in-situ concentrations in sediment cores (25 cm depth) from Mono and Searles Lakes. Sulfate reduction activity was detected in sediments from Mono Lake, with the highest rates occurring in the upper 2 cm sediment depth. No sulfate reduction activity was observed in Searles Lake sediments, suggesting that this metabolic process may not provide sufficient energy to cope with the demands of osmoadaptation at saturated salt concentrations. Anaerobic pathways that utilize As(V) or nitrate as terminal electron acceptors are bioenergetically more favorable than sulfate reduction. Dissimilatory reduction of As(V) occurred in sediments from both lakes, with the fastest rates of As(V) reduction occurring at 3 cm sediment depth. We conducted additional experiments with As- or nitrate-amended slurries of Searles Lake sediment prepared in artificial media that mimicked lake water chemistry over a range of total salinities. Slurries were sampled periodically and analyzed to determine the rate of As(V) reduction or denitrification at each salinity. Methane production was also monitored in the headspace of As(V)-amended and non-amended slurries. As(V) and nitrate reduction rates, as well as methane production, demonstrated an inverse relationship with total salinity over the range of 50 - 346 g/L. These data suggest that halophilic bacteria capable of

  5. Different arsenate and phosphate incorporation effects on the nucleation and growth of iron(III) (Hydr)oxides on quartz.

    Science.gov (United States)

    Neil, Chelsea W; Lee, Byeongdu; Jun, Young-Shin

    2014-10-21

    Iron(III) (hydr)oxides play an important role in the geochemical cycling of contaminants in natural and engineered aquatic systems. The ability of iron(III) (hydr)oxides to immobilize contaminants can be related to whether the precipitates form heterogeneously (e.g., at mineral surfaces) or homogeneously in solution. Utilizing grazing incidence small-angle X-ray scattering (GISAXS), we studied heterogeneous iron(III) (hydr)oxide nucleation and growth on quartz substrates for systems containing arsenate and phosphate anions. For the iron(III) only system, the radius of gyration (Rg) of heterogeneously formed precipitates grew from 1.5 to 2.5 (± 1.0) nm within 1 h. For the system containing 10(-5) M arsenate, Rg grew from 3.6 to 6.1 (± 0.5) nm, and for the system containing 10(-5) M phosphate, Rg grew from 2.0 to 4.0 (± 0.2) nm. While the systems containing these oxyanions had more growth, the system containing only iron(III) had the most nucleation events on substrates. Ex situ analyses of homogeneously and heterogeneously formed precipitates indicated that precipitates in the arsenate system had the highest water content and that oxyanions may bridge iron(III) hydroxide polymeric embryos to form a structure similar to ferric arsenate or ferric phosphate. These new findings are important because differences in nucleation and growth rates and particle sizes will impact the number of available reactive sites and the reactivity of newly formed particles toward aqueous contaminants. PMID:25232994

  6. Chapter 2 Anion Sorption Topology on Hematite: Comparison of Arsenate and Silicate

    International Nuclear Information System (INIS)

    Arsenate and silicate are tetrahedral anions that strongly sorb to positive Fe oxide surfaces over the pH range 2-7. Both are important agents for modification of Fe oxide surface reactivity, and notably passivate against other sorption reactions. Arsenate is a significant health hazard as a sorbed pollutant associated with acid mine drainage, while silicate is a common anion in natural solutions. Our aim is to understand the types of sorption complexes that form with these anions on different crystal faces, and whether polymerization occurs with the silicate units. Silicate polymerization could dramatically alter Fe oxide surface reactivity. The structural characterization is conducted using both grazing incidence extended X-ray absorption fine structure (GIEXAFS) at Stanford Synchrotron Radiation Laboratory (SSRL) and the National Synchrotron Light Source (NSLS), and surface diffraction (using crystal truncation rod (CTR) analysis) at the Advanced Photon Source (APS). GIEXAFS yields interatomic distances from arsenic and silicon to their oxygen first neighbor shell and second Fe or other next neighbor shell, and thus allows identification of the local geometry of sorption. Polarized X-ray fine structure spectroscopy further allows determination of the orientation and density of the complexes on the various Fe surface planes. However, this information is incomplete as any response of the surface to sorption is not revealed, and hydrogen bonding and water molecule arrangement at the surface can be changed due to the sorption process. To access these we use CTR experiments and compare the results with samples without sorbed anions. GIEXAFS results for both hematite (0 0 0 1) and (1(bar 1)02) planes show arsenate sorbed in two ways: bidentate binuclear and bidentate mononuclear. Most of the latter type of sorption geometry appears to be present on surface step edges on the (1(bar 1)02) surface, while there is little or no such attachment to the (1(bar 1)02) surface

  7. Surface chemistry of ferrihydrite: Part 2. Kinetics of arsenate adsorption and coprecipitation

    Science.gov (United States)

    Fuller, C.C.; Dadis, J.A.; Waychunas, G.A.

    1993-01-01

    The kinetics of As(V) adsorption by ferrihydrite was investigated in coprecipitation and postsynthesis adsorption experiments conducted in the pH range 7.5-9.0. In coprecipitation experiments, As(V) was present in solution during the hydrolysis and precipitation of iron. In adsorption experiments, a period of rapid (adsorption sites on ferrihydrite surfaces within aggregates of colloidal particles. The time dependence of As(V) adsorption is well described by a general model for diffusion into a sphere if a subset of surface sites located near the exterior of aggregates is assumed to attain adsorptive equilibrium rapidly. The kinetics of As(V) desorption after an increase in pH were also consistent with diffusion as a rate-limiting process. Aging of pure ferrihydrite prior to As(V) adsorption caused a decrease in adsorption sites on the precipitate owing to crystallite growth. In coprecipitation experiments, the initial As(V) uptake was significantly greater than in post-synthesis adsorption experiments, and the rate of uptake was not diffusion limited because As(V) was coordinated by surface sites before crystallite growth and coagulation processes could proceed. After the initial adsorption, As(V) was slowly released from coprecipitates for at least one month, as crystallite growth caused desorption of As(V). Adsorption densities as high as 0.7 mole As(V) per mole of Fe were measured in coprecipitates, in comparison to 0.25 mole As(V) per mole of Fe in post-synthesis adsorption experiments. Despite the high Concentration of As(V) in the precipitates, EXAFS spectroscopy (Waychunas et al., 1993) showed that neither ferric arsenate nor any other As-bearing surface precipitate or solid solution was formed. The high adsorption densities are possible because the ferrihydrite particles are extremely small, approaching the size of small dioctahedral chains at the highest As(V) adsorption density. The results suggest that the solid solution model proposed by Fox (1989

  8. Removal of toxic ions (chromate, arsenate, and perchlorate) using reverse osmosis, nanofiltration, and ultrafiltration membranes

    KAUST Repository

    Yoon, Jaekyung

    2009-09-01

    Rejection characteristics of chromate, arsenate, and perchlorate were examined for one reverse osmosis (RO, LFC-1), two nanofiltration (NF, ESNA, and MX07), and one ultrafiltration (UF and GM) membranes that are commercially available. A bench-scale cross-flow flat-sheet filtration system was employed to determine the toxic ion rejection and the membrane flux. Both model and natural waters were used to prepare chromate, arsenate, and perchlorate solutions (approximately 100 μg L-1 for each anion) in mixtures in the presence of other salts (KCl, K2SO4, and CaCl2); and at varying pH conditions (4, 6, 8, and 10) and solution conductivities (30, 60, and 115 mS m-1). The rejection of target ions by the membranes increases with increasing solution pH due to the increasingly negative membrane charge with synthetic model waters. Cr(VI), As(V), and ClO4 - rejection follows the order LFC-1 (>90%) > MX07 (25-95%) ≅ ESNA (30-90%) > GM (3-47%) at all pH conditions. In contrast, the rejection of target ions by the membranes decreases with increasing solution conductivity due to the decreasingly negative membrane charge. Cr(VI), As(V), and ClO4 - rejection follows the order CaCl2 < KCl ≅ K2SO4 at constant pH and conductivity conditions for the NF and UF membranes tested. For natural waters the LFC-1 RO membrane with a small pore size (0.34 nm) had a significantly greater rejection for those target anions (>90%) excluding NO3 - (71-74%) than the ESNA NF membrane (11-56%) with a relatively large pore size (0.44 nm), indicating that size exclusion is at least partially responsible for the rejection. The ratio of solute radius (ri,s) to effective membrane pore radius (rp) was employed to compare ion rejection. For all of the ions, the rejection is higher than 70% when the ri,s/rp ratio is greater than 0.4 for the LFC-1 membrane, while for di-valent ions (CrO4 2 -, SO4 2 -, and HAsSO4 2 -) the rejection (38-56%) is fairly proportional to the ri,s/rp ratio (0.32-0.62) for the ESNA

  9. SCREENING OF HMG CO A REDUCTASE INHIBITOR PRODUCING MARINE ACTINOMYCETES

    OpenAIRE

    SRINU, PHANI BHUSHAN,MOGES, SRILAKSHMI, SANKAR, PRABHAKAR,LAKSHMINARAYANA

    2013-01-01

    The objective of the present study was screening of 3-hydroxy-3- methyl glutaryl Co A (HMG CoA) reductase inhibitor producing marine actinomycetes. A total of 65 morphologically different actinomycetes were screened for HMG CoA reductase inhibitor production in a two stage submerged fermentation and evaluated for HMG CoA reductase inhibitor activity by agar diffusion and thin layer chromatography technique using lovostatin as a control. Among 65 marine Actinomycete strains, only one strain pr...

  10. Characterization of the chlorate reductase from Pseudomonas chloritidismutans

    OpenAIRE

    Wolterink, A.F.W.M.; Schiltz, E; Hagedoorn, P.L.; Hagen, W.R.; Kengen, S.W.M.; Stams, A.J.M.

    2003-01-01

    A chlorate reductase has been purified from the chlorate-reducing strain Pseudomonas chloritidismutans. Comparison with the periplasmic (per)chlorate reductase of strain GR-1 showed that the cytoplasmic chlorate reductase of P. chloritidismutans reduced only chlorate and bromate. Differences were also found in N-terminal sequences, molecular weight, and subunit composition. Metal analysis and electron paramagnetic resonance measurements showed the presence of iron and molybdenum, which are al...

  11. Characterization of the Chlorate Reductase from Pseudomonas chloritidismutans

    OpenAIRE

    2003-01-01

    A chlorate reductase has been purified from the chlorate-reducing strain Pseudomonas chloritidismutans. Comparison with the periplasmic (per)chlorate reductase of strain GR-1 showed that the cytoplasmic chlorate reductase of P. chloritidismutans reduced only chlorate and bromate. Differences were also found in N-terminal sequences, molecular weight, and subunit composition. Metal analysis and electron paramagnetic resonance measurements showed the presence of iron and molybdenum, which are al...

  12. In situ characterization of green rust in the presence of arsenate and phosphate in simulated oxidized and reduced environments.

    Science.gov (United States)

    Root, R. A.; O'Day, P. A.

    2008-12-01

    Nano- to micron-scale particles of mixed-valent iron hydroxide, specifically green rust (GR [FeII6- x(OH)y FeIIIx(OH)12-y]x+[Anionx- + H2O]x-), have been identified and studied as corrosion products of steel, and recently rediscovered in hydromorphic soils and sediments. Green rusts are intermediate phases produced by biotic and abiotic reductive dissolution of ferric oxyhydroxides, or by oxidation of dissolved ferrous iron. Adsorbed oxyanions can stabilize GR phases and inhibit the formation of thermodynamically favored iron phases such as magnetite or lepidocrocite in subsurface environments. This study used synchrotron XRD to characterize iron (hydr)oxide minerals precipitated from solution and subsequent aging products under different environmental conditions of pH and Eh. Here we show the in situ abiotic development of green rust and its stabilization by the addition of adsorbed oxyanions or alternatively, subsequent rapid transformation to magnetite or lepidocrocite in the absence of added anions. A closed batch reactor with an in-line capillary was used to expose the reaction products to continuous synchrotron radiation. Laue patterns were collected at time intervals of 3-5 minutes and used to detect the formation of crystalline iron (hydr)oxide minerals that precipitate as a function time and chemical perturbations to the system, i.e. changing the pH, redox potential, ratio of Fe2+ to OH- , and addition of an oxyanion, arsenate or phosphate. The reactions were monitored by observing the development of diagnostic green rust XRD d-spacing peak at 10.9 Å (300), the 3.29 Å (210) d- spacing for lepidocrocite, and the 2.53 Å (100) d-spacing for magnetite, with continuous in-line measurement of pH and ORP. We found that green rust was stabilized by the adsorption of arsenate and phosphate. In the presence of arsenate or phosphate at pH =7, green rust transformed to lepidocrocite after several hours when anoxic controls were removed. When pH and Eh were constant

  13. Arsenate (As V) in water: quantitative sensitivity relationships among biomarker, ecotoxicity and genotoxicity endpoints.

    Science.gov (United States)

    Silva, Valéria C; Almeida, Sônia M; Resgalla, Charrid; Masfaraud, Jean-François; Cotelle, Sylvie; Radetski, Claudemir M

    2013-06-01

    It is useful to test ecotoxicity and genotoxicity endpoints in the environmental impact assessment. Here, we compare and discuss ecotoxicity and genotoxicity effects in organisms in response to exposure to arsenate (As V) in solution. Eco(geno)toxicity responses in Aliivibrio fischeri, Lytechinus variegatus, Daphnia magna, Skeletonema costatum and Vicia faba were analyzed by assessing different endpoints: biomass growth, peroxidase activity, mitotic index, micronucleus frequency, and lethality in accordance with the international protocols. Quantitative sensitivity relationships (QSR) between these endpoints were established in order to rank endpoint sensitivity. The results for the QSR values based on the lowest observed effect concentration (LOEC) ratios varied from 2 (for ratio of root peroxidase activity to leaf peroxidase activity) to 2286 (for ratio of higher plant biomass growth to root peroxidase activity). The QSR values allowed the following sensitivity ranking to be established: higher plant enzymatic activity>daphnids≈echinoderms>bacteria≈algae>higher plant biomass growth. The LOEC values for the mitotic index and micronucleus frequency (LOEC=0.25mgAsL(-1)) were similar to the lowest LOEC values observed in aquatic organisms. This approach to the QSR of different endpoints could form the basis for monitoring and predicting early effects of pollutants before they give rise to significant changes in natural community structures. PMID:23597676

  14. Arsenic and Chromium Partitioning in a Podzolic Soil Contaminated by Chromated Copper Arsenate

    Energy Technology Data Exchange (ETDEWEB)

    Hopp, L.; Nico, P.S.; Marcus, M.A.; Peiffer, S. (Bayreuth); (LBNL)

    2008-10-14

    This research combined the use of selective extractions and X-ray spectroscopy to examine the fate of As and Cr in a podzolic soil contaminated by chromated copper arsenate (CCA). Iron was enriched in the upper 30 cm due to a previous one-time treatment of the soil with Fe(II). High oxalate-soluble Al concentrations in the Bs horizon of the soil and micro-XRD data indicated the presence of short-range ordered aluminosilicates (i.e., proto-imogolite allophane, PIA). In the surface layers, Cr, as Cr(III), was partitioned between a mixed Fe(III)/Cr(III) solid phase that formed upon the Fe(II) application (25--50%) and a recalcitrant phase (50--75%) likely consisting of organic material such as residual CCA-treated wood. Deeper in the profile Cr appeared to be largely in the form of extractable (hydr)oxides. Throughout the soil, As was present as As(V). In the surface layers a considerable fraction of As was also associated with a recalcitrant phase, probably CCA-treated woody debris, and the remainder was associated with (hydr)oxide-like solid phases. In the Bs horizon, however, XAS and XRF findings strongly pointed to the presence of PIA acting as an effective adsorbent for As. This research shows for the first time the relevance of PIA for the adsorption of As in natural soils.

  15. Arsenic and chromium partitioning in a podzolic soil contaminated by chromated copper arsenate

    Energy Technology Data Exchange (ETDEWEB)

    Nico, Peter; Hopp, Luisa; Nico, Peter S.; Marcus, Matthew A.; Peiffer, Stefan

    2008-06-01

    This research combined the use of selective extractions and x-ray spectroscopy to examine the fate of As and Cr in a podzolic soil contaminated by chromated copper arsenate (CCA). Iron was enriched in the upper 30 cm due to a previous one-time treatment of the soil with Fe(II). High oxalate-soluble Al concentrations in the Bs horizon of the soil and micro-XRD data indicated the presence of short-range ordered aluminosilicates (i.e. proto-imogolite allophane, PIA). In the surface layers, Cr, as Cr(III), was partitioned between a mixed Fe(III)/Cr(III) solid phase that formed upon the Fe(II) application (25-50%) and a recalcitrant phase (50-75%) likely consisting of organic material such as residual CCA-treated wood. Deeper in the profile Cr appeared to be largely in the form of extractable (hydr)oxides. Throughout the soil, As was present as As(V). In the surface layers a considerable fraction of As was also associated with a recalcitrant phase, probably CCA-treated woody debris, and the remainder was associated with (hydr)oxide-like solid phases. In the Bs horizon, however, XAS and XRF findings strongly pointed to the presence of PIA acting as an effective adsorbent for As. This research shows for the first time the relevance of PIA for the adsorption of As in natural soils.

  16. Arsenate (As) uptake by and distribution in two cultivars of winter wheat (Triticum aestivum L.).

    Science.gov (United States)

    Geng, Chun-Nu; Zhu, Yong-Guan; Tong, Yi-Ping; Smith, Sally E; Smith, F A

    2006-01-01

    Two cultivars of winter wheat (Triticum aestivum L.) (Jing 411 and Lovrin 10) were used to investigate arsenate (As) uptake and distribution in plants grown in hydroponic culture and in the soil. Results showed that without As addition, Lovrin 10 had higher biomass than Jing 411 in the soil pot experiment; in the hydroponic experiment Lovrin 10 had similar root biomass to and lower shoot biomass than Jing 411. Increasing P supply from 32 to 161 microM resulted in lower tissue As concentrations, and increasing As supply from 0 to 2,000 microM resulted in lower tissue P concentrations. Increasing P supply tended to increase shoot-to-root ratios of As concentrations, and increasing As supply tended to decrease shoot-to-root ratios of As concentrations. Both cultivars invested more in root production under P deficient conditions than under P sufficient conditions. Lovrin 10 invested more biomass production to roots than Jing 411, which might be partly responsible for higher shoot P and As concentrations and higher shoot-to-root ratios of As concentrations. Moreover, Lovrin 10 allocated less As to roots than Jing 411 and the difference disappeared with decreasing P supply. PMID:16081139

  17. Solid solutions of hydrogen uranyl phosphate and hydrogen uranyl arsenate. A family of luminescent, lamellar hosts

    International Nuclear Information System (INIS)

    Hydrogen uranyl phosphate, HUO2PO4 x 4H2O (HUP), and hydrogen uranyl arsenate, HUO2AsO4 x 4H2O (HUAs), form solid solutions of composition HUO2(PO4)1-x(AsO4)x (HUPAs), representing a family of lamellar, luminescent solids that can serve as hosts for intercalation chemistry. The solids are prepared by aqueous precipitation reactions from uranyl nitrate and mixtures of phosphoric and arsenic acids; thermogravimetric analysis indicates that the phases are tetrahydrates, like HUP and HUAs. Powder x-ray diffraction data reveal the HUPAs solids to be single phases whose lattice constants increase with X, in rough accord with Vegard's law Spectral shifts observed for the HUPAs samples. Emission from the solids is efficient (quantum yields of ∼ 0.2) and long-lived (lifetimes of ∼ 150 μs), although the measured values are uniformly smaller than those of HUP and HUAs; unimolecular radiative and nonradiative rate constants for excited-state decay of ∼ 1500 and 5000 s-1, respectively, have been calculated for the compounds. 18 refs., 5 figs., 2 tabs

  18. Preparation and performance of arsenate (V) adsorbents derived from concrete wastes.

    Science.gov (United States)

    Sasaki, Takeshi; Iizuka, Atsushi; Watanabe, Masayuki; Hongo, Teruhisa; Yamasaki, Akihiro

    2014-10-01

    Solid adsorbent materials, prepared from waste cement powder and concrete sludge were assessed for removal of arsenic in the form of arsenic (As(V)) from water. All the materials exhibited arsenic removal capacity when added to distilled water containing 10-700 mg/L arsenic. The arsenic removal isotherms were expressed by the Langmuir type equations, and the highest removal capacity was observed for the adsorbent prepared from concrete sludge with heat treatment at 105°C, the maximum removal capacity being 175 mg-As(V)/g. Based on changes in arsenic and calcium ion concentrations, and solution pH, the removal mechanism for arsenic was considered to involve the precipitation of calcium arsenate, Ca3(AsO4)2. The enhanced removal of arsenic for the adsorbent prepared from concrete sludge with heat treatment was thought to reflect ion exchange by ettringite. The prepared adsorbents, derived from waste cement and concrete using simple procedures, may offer a cost effective approach for arsenic removal and clean-up of contaminated waters, especially in developing countries. PMID:24472713

  19. Co-adsorption of Trichloroethylene and Arsenate by Iron-Impregnated Granular Activated Carbon.

    Science.gov (United States)

    Deng, Baolin; Kim, Eun-Sik

    2016-05-01

    Co-adsorption of trichloroethylene (TCE) and arsenate [As(V)] was investigated using modified granular activated carbons (GAC): untreated, sodium hypochlorite-treated (NaClO-GAC), and NaClO with iron-treated GAC (NaClO/Fe-GAC). Batch experiments of single- [TCE or As(V)] and binary- [TCE and As(V)] components solutions are evaluated through Langmuir and Freundlich isotherm models and adsorption kinetic tests. In the single-component system, the adsorption capacity of As(V) was increased by the NaClO-GAC and the NaClO/Fe-GAC. The untreated GAC showed a low adsorption capacity for As(V). Adsorption of TCE by the NaClO/Fe-GAC was maximized, with an increased Freundlich constant. Removal of TCE in the binary-component system was decreased 15% by the untreated GAC, and NaClO- and NaClO/Fe-GAC showed similar efficiency to the single-component system because of the different chemical status of the GAC surfaces. Results of the adsorption isotherms of As(V) in the binary-component system were similar to adsorption isotherms of the single-component system. The adsorption affinities of single- and binary-component systems corresponded with electron transfer, competitive adsorption, and physicochemical properties. PMID:27131303

  20. Effects of Sodium Arsenite and Arsenate in Testicular Histomorphometry and Antioxidants Enzymes Activities in Rats.

    Science.gov (United States)

    Souza, Ana Cláudia Ferreira; Marchesi, Sarah Cozzer; Domingues de Almeida Lima, Graziela; Ferraz, Rafael Penha; Santos, Felipe Couto; da Matta, Sérgio Luis Pinto; Machado-Neves, Mariana

    2016-06-01

    The main source of environmental arsenic exposure in most countries of the world is drinking water in which inorganic forms of arsenic predominate. The present study was aimed to test the impact of two different compounds of inorganic arsenic in histomorphometric and enzymatic parameters in the testes by oral exposition. Adult Wistar male rats were exposed to sodium arsenite and arsenate in drinking water, testing for each chemical form the concentrations of 0.01 and 10 mg/L per 56 days. The animals intoxicated with arsenic, mainly sodium arsenite, showed reduction in the percentage of seminiferous epithelium and in proportion and volume of Leydig cells. Moreover, there was an increase in the percentage of tunica propria, lumen, lymphatic space, blood vessels, and macrophages. The activity of superoxide dismutase (SOD) did not change among the groups. However, the activity of catalase (CAT) decreased in animals exposed to both arsenic compounds. In addition, the higher concentration of arsenic, mainly as sodium arsenite, caused vacuolization in the seminiferous epithelium. The body and testes weight as well as testosterone concentration remained unchanged among the groups. In conclusion, exposition to arsenic, mainly as sodium arsenite, caused alteration in histomorphometric parameters and antioxidant defense system in the testes. PMID:26446860

  1. Tolerance, arsenic uptake, and oxidative stress in Acacia farnesiana under arsenate-stress.

    Science.gov (United States)

    Alcantara-Martinez, Nemi; Guizar, Sandra; Rivera-Cabrera, Fernando; Anicacio-Acevedo, Blanca E; Buendia-Gonzalez, Leticia; Volke-Sepulveda, Tania

    2016-07-01

    Acacia farnesiana is a shrub widely distributed in soils heavily polluted with arsenic in Mexico. However, the mechanisms by which this species tolerates the phytotoxic effects of arsenic are unknown. This study aimed to investigate the tolerance and bioaccumulation of As by A. farnesiana seedlings exposed to high doses of arsenate (AsV) and the role of peroxidases (POX) and glutathione S-transferases (GST) in alleviating As-stress. For that, long-period tests were performed in vitro under different AsV treatments. A. farnesiana showed a remarkable tolerance to AsV, achieving a half-inhibitory concentration (IC50) of about 2.8 mM. Bioaccumulation reached about 940 and 4380 mg As·kg(-1) of dry weight in shoots and roots, respectively, exposed for 60 days to 0.58 mM AsV. Seedlings exposed to such conditions registered a growth delay during the first 15 days, when the fastest As uptake rate (117 mg kg(-1) day(-1)) occurred, coinciding with both the highest rate of lipid peroxidation and the strongest up-regulation of enzyme activities. GST activity showed a strong correlation with the As bioaccumulated, suggesting its role in imparting AsV tolerance. This study demonstrated that besides tolerance to AsV, A. farnesiana bioaccumulates considerable amounts of As, suggesting that it may be useful for phytostabilization purposes. PMID:26618535

  2. Structure and mechanism of dimethylsulfoxide reductase, a molybdopterin-containing enzyme of DMSO reductase family

    International Nuclear Information System (INIS)

    Full text: Apart from nitrogenase, enzymes containing molybdenum are members of a superfamily, the molybdopterin-containing enzymes. Most of these enzymes catalyse an oxygen atom transfer and two electron transfer reaction. During catalysis the Mo at the active site cycles between the Mo(VI) and Mo(IV) states. The DMSO reductase family of molybdopterin-containing enzymes all contain a bis(molybdopterin guanine dinucleotide)Mo cofactor and over thirty examples have now been described. Over the last five years crystal structures of dimethylsulfoxide (DMSO) reductase and four other enzymes of the DMSO reductase family have revealed that enzymes of this family have a similar tertiary structure. The Mo atom at the active site is coordinated by four thiolate ligands provided by the dithiolene side chains of the two MGD molecules of the bis(MGD)Mo cofactor as well as a ligand provided by an amino acid side chain. In addition, an oxygen atom in the form of an oxo, hydroxo or aqua group is also coordinated to the Mo atom. In the case of dimethylsulfoxide reductase X-ray crystallography of the product-reduced species and Raman spectroscopy has demonstrated that the enzyme contains a single exchangeable oxo group that is H-bonded to W116

  3. Structure and function of NADPH-cytochrome P450 reductase and nitric oxide synthase reductase domain

    International Nuclear Information System (INIS)

    NADPH-cytochrome P450 reductase (CPR) and the nitric oxide synthase (NOS) reductase domains are members of the FAD-FMN family of proteins. The FAD accepts two reducing equivalents from NADPH (dehydrogenase flavin) and FMN acts as a one-electron carrier (flavodoxin-type flavin) for the transfer from NADPH to the heme protein, in which the FMNH ·/FMNH2 couple donates electrons to cytochrome P450 at constant oxidation-reduction potential. Although the interflavin electron transfer between FAD and FMN is not strictly regulated in CPR, electron transfer is activated in neuronal NOS reductase domain upon binding calmodulin (CaM), in which the CaM-bound activated form can function by a similar mechanism to that of CPR. The oxygenated form and spin state of substrate-bound cytochrome P450 in perfused rat liver are also discussed in terms of stepwise one-electron transfer from CPR. This review provides a historical perspective of the microsomal mixed-function oxidases including CPR and P450. In addition, a new model for the redox-linked conformational changes during the catalytic cycle for both CPR and NOS reductase domain is also discussed

  4. Physical, Chemical, and Biological Methods for the Removal of Arsenic Compounds

    Directory of Open Access Journals (Sweden)

    K. T. Lim

    2014-01-01

    Full Text Available Arsenic is a toxic metalloid which is widely distributed in nature. It is normally present as arsenate under oxic conditions while arsenite is predominant under reducing condition. The major discharges of arsenic in the environment are mainly due to natural sources such as aquifers and anthropogenic sources. It is known that arsenite salts are more toxic than arsenate as it binds with vicinal thiols in pyruvate dehydrogenase while arsenate inhibits the oxidative phosphorylation process. The common mechanisms for arsenic detoxification are uptaken by phosphate transporters, aquaglyceroporins, and active extrusion system and reduced by arsenate reductases via dissimilatory reduction mechanism. Some species of autotrophic and heterotrophic microorganisms use arsenic oxyanions for their regeneration of energy. Certain species of microorganisms are able to use arsenate as their nutrient in respiratory process. Detoxification operons are a common form of arsenic resistance in microorganisms. Hence, the use of bioremediation could be an effective and economic way to reduce this pollutant from the environment.

  5. Newborn Respiratory Distress.

    Science.gov (United States)

    Hermansen, Christian L; Mahajan, Anand

    2015-12-01

    Newborn respiratory distress presents a diagnostic and management challenge. Newborns with respiratory distress commonly exhibit tachypnea with a respiratory rate of more than 60 respirations per minute. They may present with grunting, retractions, nasal flaring, and cyanosis. Common causes include transient tachypnea of the newborn, respiratory distress syndrome, meconium aspiration syndrome, pneumonia, sepsis, pneumothorax, persistent pulmonary hypertension of the newborn, and delayed transition. Congenital heart defects, airway malformations, and inborn errors of metabolism are less common etiologies. Clinicians should be familiar with updated neonatal resuscitation guidelines. Initial evaluation includes a detailed history and physical examination. The clinician should monitor vital signs and measure oxygen saturation with pulse oximetry, and blood gas measurement may be considered. Chest radiography is helpful in the diagnosis. Blood cultures, serial complete blood counts, and C-reactive protein measurement are useful for the evaluation of sepsis. Most neonates with respiratory distress can be treated with respiratory support and noninvasive methods. Oxygen can be provided via bag/mask, nasal cannula, oxygen hood, and nasal continuous positive airway pressure. Ventilator support may be used in more severe cases. Surfactant is increasingly used for respiratory distress syndrome. Using the INSURE technique, the newborn is intubated, given surfactant, and quickly extubated to nasal continuous positive airway pressure. Newborns should be screened for critical congenital heart defects via pulse oximetry after 24 hours but before hospital discharge. Neonatology consultation is recommended if the illness exceeds the clinician's expertise and comfort level or when the diagnosis is unclear in a critically ill newborn. PMID:26760414

  6. Membrane-associated chromate reductase activity from Enterobacter cloacae.

    OpenAIRE

    P. C. Wang; Mori, T.; Toda, K.; Ohtake, H

    1990-01-01

    Washed cells of Enterobacter cloacae HO1 reduced hexavalent chromium (chromate: CrO4(2-) anaerobically. Chromate reductase activity was preferentially associated with the membrane fraction of the cells. Right-side-out membrane vesicles prepared from E. cloacae cells showed high chromate reductase activities when ascorbate-reduced phenazine methosulfate was added as an electron donor.

  7. Canopy and seasonal profiles of nitrate reductase in soybeans

    Energy Technology Data Exchange (ETDEWEB)

    Harper, J.E.; Hageman, R.H.

    1972-01-01

    Nitrate reductase activity of soybeans (Glycine max L. Merr.) was evaluated in soil plots and outdoor hydroponic gravel culture systems throughout the growing season. Nitrate reductase profiles within the plant canopy were also established. Mean activity per gram fresh weight per hour of the entire plant canopy was highest in the seedling stage while total activity (activity per gram fresh weight per hour times the total leaf weight) reached a maximum when plants were in the full bloom to midpod fill stage. Nitrate reductase activity per gram fresh weight per hour was highest in the uppermost leaf just prior to full expansion and declined with leaf positions lower in the canopy. Total nitrate reductase activity per leaf was also highest in the uppermost fully expanded leaf during early growth stages. Maximum total activity shifted to leaf positions lower in the plant canopy with later growth stages. Nitrate reductase activity of soybeans grown in hydroponic systems was significantly higher than activity of adjacent soil grown plants at later growth stages, which suggested that under normal field conditions the potential for nitrate utilization may not be realized. Nitrate reductase activity per gram fresh weight per hour and nitrate content were positively correlated over the growing season with plants grown in either soil or solution culture. Computations based upon the nitrate reductase assay of plants grown in hydroponics indicated that from 1.7 to 1.8 grams N could have been supplied to the plant via the nitrate reductase process. 11 references, 9 figures, 3 tables.

  8. Dicty_cDB: VSC623 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available VS (Link to library) VSC623 (Link to dictyBase) - G23846 DDB0188878 Contig-U05855-1 VSC623E (Lin ... 38 6.1 2 AY271310 |AY271310.1 Shewanella sp. ANA-3 arsenic ... resistance operon, arsenate respiratory reductase ...

  9. ARSENATE BIOSORPTION BY IRON-MODIFIED PINE SAWDUST IN BATCH SYSTEMS: KINETICS AND EQUILIBRIUM STUDIES

    Directory of Open Access Journals (Sweden)

    María Aranzazú López-Leal,

    2012-02-01

    Full Text Available The biosorption of As(V from aqueous solutions by pine sawdust chemically modified with iron in batch systems was investigated. The loading process of Fe in this biomaterial was achieved by hydrolysis of two different ferric salts. This modification of sawdust is an attempt to improve As(V biosorption for practical applications. The kinetics and maximum biosorption capacities of the unmodified and modified pine sawdust were evaluated. It was found that the pseudo-second order model described the As(V biosorption kinetic data and the Langmuir-Freundlich equation described the arsenate sorption equilibrium. These results indicated that the sorption mechanism was chemisorption on a heterogeneous material. The pH effects governing biosorption capacities were also evaluated, showing a decrease as pH value rises, indicating that this biosorption process is highly pH-dependent. The estimated maximum biosorption capacities of As(V, based on the Langmuir-Freundlich fit to the data were, at pH 4, 4.4 mg/g of untreated sawdust, (UN-SW, 12.85 mg/g of ferric chloride modified sawdust (FeCl-SW, and 6 mg/g of ferric nitrate modified sawdust (FeNit-SW; and at pH 7, 2.6 mg/g of UN-SW, 5.9 mg/g of FeCl-SW, and 4.6 mg/g of FeNit-SW. Sorption capacities of iron-modified pine sawdust were evidently higher than other similar biosorbents previously reported.

  10. Removal of arsenate with hydrous ferric oxide coprecipitation: effect of humic acid.

    Science.gov (United States)

    Du, Jingjing; Jing, Chuanyong; Duan, Jinming; Zhang, Yongli; Hu, Shan

    2014-02-01

    Insights from the adverse effect of humic acid (HA) on arsenate removal with hydrous ferric oxide (HFO) coprecipitation can further our understanding of the fate of As(V) in water treatment process. The motivation of our study is to explore the competitive adsorption mechanisms of humic acid and As(V) on HFO on the molecular scale. Multiple complementary techniques were used including macroscopic adsorption experiments, surface enhanced Raman scattering (SERS), extended X-ray absorption fine structure (EXAFS) spectroscopy, flow-cell attenuated total reflectance Fourier transform infrared (ATR-FTIR) measurement, and charge distribution multisite complexation (CD-MUSIC) modeling. The As(V) removal efficiency was reduced from over 95% to about 10% with the increasing HA concentration to 25 times of As(V) mass concentration. The SERS analysis excluded the HA-As(V) complex formation. The EXAFS results indicate that As(V) formed bidentate binuclear surface complexes in the presence of HA as evidenced by an As-Fe distance of 3.26-3.31 angstroms. The in situ ATR-FTIR measurements show that As(V) replaces surface hydroxyl groups and forms innersphere complex. High concentrations of HA may physically block the surface sites and inhibit the As(V) access. The adsorption of As(V) and HA decreased the point of zero charge of HFO from 7.8 to 5.8 and 6.3, respectively. The CD-MUSIC model described the zeta potential curves and adsorption edges of As(V) and HA reasonably well. PMID:25076514

  11. Determination of chromated copper arsenate (CCA) in treated wood of Eucalyptus

    International Nuclear Information System (INIS)

    This work deals with the possible application of a portable energy dispersive handmade system (PXRF-LFNA-02) for the determination of Chromium, Copper and Arsenic in the preservative solution used to protect commercial wood of Eucalyptus, which are employed as wood fence, posts, contention fences, railroad sleepers, etc. It was prepared five body-of-proof made of eucalyptus alburnum with different concentrations for each element varying from 0.0061 to 0.0180 (g/g) for CrO3, 0.0024 to 0.0070 (g/g) for CuO and 0.0044 to 0.0129 (g/g) for As2O5. Four of them were used for calibration curves and one used as reference sample. It was used a commercial CCA (Chromated Copper Arsenate ) solution to prepare the samples. The results show a good linear regression between concentrations and X-rays intensities, after applied the multiple linear regression methodology for interelemental corrections. The values obtained with this methodology were 3.01(kg/m3), 1.18 (kg/m3) e 2.21 (kg/m3) for CrO3, CuO and As2O5, respectively, while the nominal values are 2.90 (kg/m3) for CrO3, 1.13 (kg/m3) for CuO and 2.07 (kg/m3) for As2O5. The ED-XRF (Energy Dispersive X-Rays Fluorescence) is a well established technique with high-speed of analytical procedure and its portable configuration allowing a multielemental, simultaneous and non destructive analyses besides in situ application. (author)

  12. Comparison of four extraction procedures to assess arsenate and arsenite species in contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Giral, Melanie [Department of Civil, Geological and Mining Engineering, Ecole Polytechnique de Montreal, P.O. Box 6079, Station Centre-Ville, Montreal, Quebec H3C 3A7 (Canada); Zagury, Gerald J., E-mail: gerald.zagury@polymtl.c [Department of Civil, Geological and Mining Engineering, Ecole Polytechnique de Montreal, P.O. Box 6079, Station Centre-Ville, Montreal, Quebec H3C 3A7 (Canada); Deschenes, Louise [The Interuniversity Research Centre for the Life Cycle of Products, Processes and Services (CIRAIG), Department of Chemical Engineering, Ecole Polytechnique de Montreal, P.O. Box 6079, Station Centre-Ville, Montreal, Quebec H3C 3A7 (Canada); Blouin, Jean-Pierre [Centre d' expertise en analyse environnementale du Quebec, Ministere de l' Environnement, du Developpement Durable et des Parcs, 850, boulevard Vanier, Laval, Quebec H7C 2M7 (Canada)

    2010-05-15

    Inorganic arsenic in soils poses an important environmental concern. Several studies reported an oxidation of arsenite to arsenate during its extraction from soils. The objectives of this study were to (1) identify, among published procedures, an extraction method which preserves the oxidation state of arsenic and (2) to assess the influence of soil physicochemical properties on the performance of these methods. Four extraction strategies were compared: 1) 10 M HCl, 2) 15% (v/v) H{sub 3}PO{sub 4}, 3) 10 mM phosphate + 0.5% (w/v) NaDDC, and, 4) 1 M H{sub 3}PO{sub 4} + 0.5 M ascorbic acid (C{sub 6}H{sub 8}O{sub 6}). Separation and analysis of As species was performed by HPLC-ICP/MS. Oxidation of As(III) into As(V) during extraction was more important in soils with high content of Mn oxides. Extraction of arsenic from soils with 1 M H{sub 3}PO{sub 4} + 0.5 M C{sub 6}H{sub 8}O{sub 6} under microwaves was the best strategy to extract the majority of As while minimizing conversion of As(III) into As(V). - Extraction of arsenic from soils with 1 M H{sub 3}PO{sub 4} + 0.5 M C{sub 6}H{sub 8}O{sub 6} under microwaves is a suitable method to extract the majority of As while minimizing conversion of As(III) into As(V).

  13. Arsenate and cadmium co-adsorption and co-precipitation on goethite

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Wei [Environment Research Institute, Shandong University, Jinan 250100 (China); Lv, Jitao; Luo, Lei [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China); Yang, Kun [Department of Environmental Science, Zhejiang University, Hangzhou 310058 (China); Lin, Yongfeng; Hu, Fanbao [Environment Research Institute, Shandong University, Jinan 250100 (China); Zhang, Jing [State Key Laboratory of Synchrotron Radiation, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100039 (China); Zhang, Shuzhen, E-mail: szzhang@rcees.ac.cn [State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085 (China)

    2013-11-15

    Highlights: • As enhances Cd adsorption amount on goethite. • Cd fixed through precipitation is more difficult to get released. • As in co-precipitates is easier to release than in its adsorption complexes. -- Abstract: Arsenate (As(V), AsO{sub 4}{sup 3−}) and cadmium (Cd) are among the toxic elements of most concern. Their sorption behaviors on goethite were studied by batch experiments (pH edges, isotherms and kinetics) and X-ray diffraction (XRD). Arsenic coordination environment was explored by X-ray absorbance fine structure (EXAFS) analysis. Sorption isotherms of both As(V) and Cd on goethite could be divided into the adsorption-dominated and precipitation-dominated parts, while their sorption showed different pH-dependency and sorption reversibility. Cadmium adsorption was enhanced in the presence of AsO{sub 4}{sup 3−}, which could be explained by the decrease in the electrostatic potential due to the sorption of AsO{sub 4}{sup 3−} and the formation of a ternary Cd–As(V)–goethite complex. Based on the EXAFS study, AsO{sub 4}{sup 3−} adsorbed on goethite mainly formed bidentate–binuclear complex. The high loadings of Cd changed the As(V)–Fe distance and its coordination number. However, Cd did not affect the As(V) adsorption amount in the adsorption-dominated region. When As(V) and Cd formed co-precipitates, their sorption amounts were both increased. The formation of co-precipitates decreased the mobility of Cd but increased the mobility of As(V) because less As(V) was sorbed on goethite through surface complexation. This study will provide better understandings on As(V) and Cd transport and useful information on their remediation strategies.

  14. Arsenate Accumulation, Distribution, and Toxicity Associated with Titanium Dioxide Nanoparticles in Daphnia magna.

    Science.gov (United States)

    Li, Mengting; Luo, Zhuanxi; Yan, Yameng; Wang, Zhenhong; Chi, Qiaoqiao; Yan, Changzhou; Xing, Baoshan

    2016-09-01

    Titanium dioxide nanoparticles (nano-TiO2) are widely used in consumer products. Nano-TiO2 dispersion could, however, interact with metals and modify their behavior and bioavailability in aquatic environments. In this study, we characterized and examined arsenate (As(V)) accumulation, distribution, and toxicity in Daphnia magna in the presence of nano-TiO2. Nano-TiO2 acts as a positive carrier, significantly facilitating D. magna's ability to uptake As(V). As nano-TiO2 concentrations increased from 2 to 20 mg-Ti/L, total As increased by a factor of 2.3 to 9.8 compared to the uptake from the dissolved phase. This is also supported by significant correlations between arsenic (As) and titanium (Ti) signal intensities at concentrations of 2.0 mg-Ti/L nano-TiO2 (R = 0.676, P distributed in BDM (biologically detoxified metal), but Ti was mainly distributed in MSF (metal-sensitive fractions) with increasing nano-TiO2 levels. Differences in subcellular distribution demonstrated that adsorbed As(V) carried by nano-TiO2 could dissociate itself and be transported separately, which results in increased toxicity at higher nano-TiO2 concentrations. Decreased As(V) toxicity associated with lower nano-TiO2 concentrations results from unaffected As levels in MSFs (when compared to the control), where several As components continued to be adsorbed by nano-TiO2. Therefore, more attention should be paid to the potential influence of nano-TiO2 on bioavailability and toxicity of cocontaminants. PMID:27485179

  15. Inhibition of fumarate reductase in Leishmania major and L. donovani by chalcones

    DEFF Research Database (Denmark)

    Chen, M; Zhai, L; Christensen, S B;

    2001-01-01

    Our previous studies have shown that chalcones exhibit potent antileishmanial and antimalarial activities in vitro and in vivo. Preliminary studies showed that these compounds destroyed the ultrastructure of Leishmania parasite mitochondria and inhibited the respiration and the activity of mitoch......Our previous studies have shown that chalcones exhibit potent antileishmanial and antimalarial activities in vitro and in vivo. Preliminary studies showed that these compounds destroyed the ultrastructure of Leishmania parasite mitochondria and inhibited the respiration and the activity...... of mitochondrial dehydrogenases of Leishmania parasites. The present study was designed to further investigate the mechanism of action of chalcones, focusing on the parasite respiratory chain. The data show that licochalcone A inhibited the activity of fumarate reductase (FRD) in the permeabilized Leishmania major....... Since FRD exists in the Leishmania parasite and does not exist in mammalian cells, it could be an excellent target for antiprotozoal drugs....

  16. The arbuscular mycorrhizal fungus Glomus mosseae can enhance arsenic tolerance in Medicago truncatula by increasing plant phosphorus status and restricting arsenate uptake

    International Nuclear Information System (INIS)

    A pot experiment examined the biomass and As uptake of Medicago truncatula colonized by the arbuscular mycorrhizal (AM) fungus Glomus mosseae in low-P soil experimentally contaminated with different levels of arsenate. The biomass of G. mosseae external mycelium was unaffected by the highest addition level of As studied (200 mg kg-1) but shoot and root biomass declined in both mycorrhizal and non-mycorrhizal plants, indicating that the AM fungus was more tolerant than M. truncatula to arsenate. Mycorrhizal inoculation increased shoot and root dry weights by enhancing host plant P nutrition and lowering shoot and root As concentrations compared with uninoculated plants. The AM fungus may have been highly tolerant to As and conferred enhanced tolerance to arsenate on the host plant by enhancing P nutrition and restricting root As uptake. - G. mosseae was more tolerant than M. truncatula to As and may have conferred enhanced host tolerance by restricting root As uptake and enhancing P nutrition

  17. The arbuscular mycorrhizal fungus Glomus mosseae can enhance arsenic tolerance in Medicago truncatula by increasing plant phosphorus status and restricting arsenate uptake

    Energy Technology Data Exchange (ETDEWEB)

    Xu Pengliang [Key Laboratory of Plant-Soil Interactions, Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100094 (China); Christie, Peter [Key Laboratory of Plant-Soil Interactions, Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100094 (China); Agricultural and Environmental Science Department, Queen' s University Belfast, Belfast BT9 5PX (United Kingdom); Liu Yu [Key Laboratory of Plant-Soil Interactions, Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100094 (China); Zhang Junling [Key Laboratory of Plant-Soil Interactions, Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100094 (China)], E-mail: junlingz@cau.edu.cn; Li Xiaolin [Key Laboratory of Plant-Soil Interactions, Ministry of Education, College of Resources and Environmental Sciences, China Agricultural University, Beijing 100094 (China)

    2008-11-15

    A pot experiment examined the biomass and As uptake of Medicago truncatula colonized by the arbuscular mycorrhizal (AM) fungus Glomus mosseae in low-P soil experimentally contaminated with different levels of arsenate. The biomass of G. mosseae external mycelium was unaffected by the highest addition level of As studied (200 mg kg{sup -1}) but shoot and root biomass declined in both mycorrhizal and non-mycorrhizal plants, indicating that the AM fungus was more tolerant than M. truncatula to arsenate. Mycorrhizal inoculation increased shoot and root dry weights by enhancing host plant P nutrition and lowering shoot and root As concentrations compared with uninoculated plants. The AM fungus may have been highly tolerant to As and conferred enhanced tolerance to arsenate on the host plant by enhancing P nutrition and restricting root As uptake. - G. mosseae was more tolerant than M. truncatula to As and may have conferred enhanced host tolerance by restricting root As uptake and enhancing P nutrition.

  18. Noninvasive respiratory monitoring

    International Nuclear Information System (INIS)

    This book contains 10 selections. Some of the titles are: Transcutaneous Monitoring of Respiratory Gases; Computed Tomography of the Chest; Measurement and Monitoring of Exhaled Carbon Dioxide; Oximetry; and Ultrasonic Evaluation of the Chest Wall and Pleura

  19. Noninvasive respiratory monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Nochomovitz, M.L.; Cherniack, N.S.

    1986-01-01

    This book contains 10 selections. Some of the titles are: Transcutaneous Monitoring of Respiratory Gases; Computed Tomography of the Chest; Measurement and Monitoring of Exhaled Carbon Dioxide; Oximetry; and Ultrasonic Evaluation of the Chest Wall and Pleura.

  20. Upper respiratory infections.

    Science.gov (United States)

    Grief, Samuel N

    2013-09-01

    Upper respiratory infections (URIs) are infections of the mouth, nose, throat, larynx (voice box), and trachea (windpipe). This article outlines the epidemiology, etiology, diagnosis, and management of URIs, including nasopharyngitis (common cold), sinusitis, pharyngitis, laryngitis, and laryngotracheitis. PMID:23958368

  1. Living with Respiratory Failure

    Science.gov (United States)

    ... tips below. Ongoing Care If you have respiratory failure, see your doctor for ongoing medical care. Your doctor may refer you to pulmonary rehabilitation (rehab). Rehab can involve exercise training, education, and counseling. Your rehab team might include doctors, ...

  2. Obesity and respiratory diseases

    OpenAIRE

    Christopher Zammit; Helen Liddicoat; Ian Moonsie; et al

    2010-01-01

    Christopher Zammit, Helen Liddicoat, Ian Moonsie, Himender MakkerSleep and Ventilation Unit, Department of Respiratory Medicine, North Middlesex University Hospital, London, UKAbstract: The obesity epidemic is a global problem, which is set to increase over time. However, the effects of obesity on the respiratory system are often underappreciated. In this review, we will discuss the mechanical effects of obesity on lung physiology and the function of adipose tissue as an endocrine organ produ...

  3. Microspectrophotometry of respiratory pigments

    OpenAIRE

    Kavanagh, Karen Yvonne, (Thesis)

    2003-01-01

    This research thesis describes the design, construction and optical testing of three fibre-optic microspectrophotometer systems to monitor the reduction of mitochondrial respiratory pigments. The optical and biochemical characteristics of mitochondrial respiration are discussed and the current optical techniques employed in the biochemical analysis of respiratory enzymes are presented. The primary focus of this study is the system parameters surrounding the spectrophotometric determination of...

  4. Respiratory Syncytial Virus (RSV)

    Centers for Disease Control (CDC) Podcasts

    2013-02-04

    Respiratory Syncytial Virus, or RSV, causes cold-like symptoms but can be serious for infants and older adults. In this podcast, CDC’s Dr. Eileen Schneider discusses this common virus and offers tips to prevent its spread.  Created: 2/4/2013 by National Center for Immunization and Respiratory Diseases (NCIRD), Division of Viral Diseases (DVD).   Date Released: 2/13/2013.

  5. Structure and expression of human dihydropteridine reductase

    International Nuclear Information System (INIS)

    Dihydropteridine reductase catalyzes the NADH-mediated reduction of quinonoid dihydrobiopterin and is an essential component of the pterindependent aromatic amino acid hydroxylating systems. A cDNA for human DHPR was isolated from a human liver cDNA library in the vector λgt11 using a monospecific antibody against sheep DHPR. The nucleic acid sequence and amino acid sequence of human DHPR were determined from a full-length clone. A 112 amino acid sequence of sheep DHPR was obtained by sequencing purified sheep DHPR. This sequence is highly homologous to the predicted amino acid sequence of the human protein. Gene transfer of the recombinant human DHPR into COS cells leads to expression of DHPR enzymatic activity. These results indicate that the cDNA clone identified by antibody screening is an authentic and full-length cDNA for human DHPR

  6. Nitrite Reductase Activity in Engineered Azurin Variants.

    Science.gov (United States)

    Berry, Steven M; Strange, Jacob N; Bladholm, Erika L; Khatiwada, Balabhadra; Hedstrom, Christine G; Sauer, Alexandra M

    2016-05-01

    Nitrite reductase (NiR) activity was examined in a series of dicopper P.a. azurin variants in which a surface binding copper site was added through site-directed mutagenesis. Four variants were synthesized with copper binding motifs inspired by the catalytic type 2 copper binding sites found in the native noncoupled dinuclear copper enzymes nitrite reductase and peptidylglycine α-hydroxylating monooxygenase. The four azurin variants, denoted Az-NiR, Az-NiR3His, Az-PHM, and Az-PHM3His, maintained the azurin electron transfer copper center, with the second designed copper site located over 13 Å away and consisting of mutations Asn10His,Gln14Asp,Asn16His-azurin, Asn10His,Gln14His,Asn16His-azurin, Gln8Met,Gln14His,Asn16His-azurin, and Gln8His,Gln14His,Asn16His-azurin, respectively. UV-visible absorption spectroscopy, EPR spectroscopy, and electrochemistry of the sites demonstrate copper binding as well as interaction with small exogenous ligands. The nitrite reduction activity of the variants was determined, including the catalytic Michaelis-Menten parameters. The variants showed activity (0.34-0.59 min(-1)) that was slower than that of native NiRs but comparable to that of other model systems. There were small variations in activity of the four variants that correlated with the number of histidines in the added copper site. Catalysis was found to be reversible, with nitrite produced from NO. Reactions starting with reduced azurin variants demonstrated that electrons from both copper centers were used to reduce nitrite, although steady-state catalysis required the T2 copper center and did not require the T1 center. Finally, experiments separating rates of enzyme reduction from rates of reoxidation by nitrite demonstrated that the reaction with nitrite was rate limiting during catalysis. PMID:27055058

  7. Thermodynamics of arsenates, selenites, and sulfates in the oxidation zone of sulfide ores: I. Thermodynamic constants at ambient conditions

    Science.gov (United States)

    Charykova, M. V.; Krivovichev, V. G.; Depmeir, W.

    2010-12-01

    Understanding and deciphering processes proceeding near the surface are among the urgent tasks of contemporary mineralogy and geochemistry, which are especially important for resolving ecological challenges and developing principles of rational environmental management. The paper presents systematized data published on thermodynamics of minerals (arsenates, sulfates, selenites, and selenates), which are formed in the weathering zone of sulfide ores, and determines approaches to quantitative physicochemical modeling of their formation conditions. Diagrams of phase and chemical equilibria (Eh-pH, diagrams of solubility) of the subsystems of the model system Fe-Cu-Zn-Pb-Co-Ni-As-Se-S-H2O (Fe2+, Fe3+, Cu2+, Zn2+, Pb2+, Ni2+, Co2+, H+//SeO{3/2-}, SeO{4/2-}, AsO{4/3-}, SO{4/2-}, OH--H2O) are used as a thermodynamic basis for modeling mineral-forming processes in the weathering zone of ore deposits. Seventy-two arsenates, about 70 sulfates, and 7 selenites and selenates have been identified in the framework of this system. The available published values of standard thermodynamic functions of the formation of minerals and chemical compounds are given, as well as the Pitzer equation parameters to describe the sulfate systems, which are substantially specific due to the high solubility of their components.

  8. Aerobic Reduction of Arsenate by a Bacterium Isolated From Activated Sludge

    Science.gov (United States)

    Kozai, N.; Ohnuki, T.; Hanada, S.; Nakamura, K.; Francis, A. J.

    2006-12-01

    Microlunatus phosphovorus strain NM-1 is a polyphosphate-accumulating bacterium isolated from activated sludge. This bacterium takes up a large amount of polyphosphate under aerobic conditions and release phosphate ions by hydrolysis of polyphosphate to orthophosphate under anaerobic conditions to derive energy for taking up substrates. To understand the nature of this strain, especially, influence of potential contaminants in sewage and wastewater on growth, we have been investigating behavior of this bacterium in media containing arsenic. The present paper mainly reports reduction of arsenate by this bacterium under aerobic conditions. The strain NM-1 (JCM 9379) was aerobically cultured at 30 °C in a nutrient medium containing 2.5 g/l peptone, 0.5 g/l glucose, 1.5 g/l yeast extract, and arsenic [Na2HAsO4 (As(V)) or Na3AsO3 (As(III))] at concentrations between 0 and 50 mM. The cells collected from arsenic-free media were dispersed in buffer solutions containing 2mM HEPES, 10mM NaCl, prescribed concentrations of As(V), and 0-0.2 percent glucose. Then, this cell suspension was kept at 20 °C under aerobic or anaerobic conditions. The speciation of arsenic was carried out by ion chromatography and ICP-MS. The growth of the strain under aerobic conditions was enhanced by the addition of As(V) at the concentration between 1 and 10 mM. The maximum optical density of the culture in the medium containing 5mM As(V) was 1.4 times greater than that of the control culture. Below the As(V) concentration of 10mM, most of the As(V) was reduced to As(III). The growth of the strain under anaerobic conditions has not been observed so far. The cells in the buffer solutions reduced As(V) under aerobic condition. The reduction was enhanced by the addition of glucose. However, the cell did not reduce As(V) under anaerobic conditions. The strain NM-1 showed high resistance to As(V) and As(III). The maximum optical density of the culture grown in a medium containing 50 mM As(V) was only

  9. Arsenate toxicity and metabolism in the halotolerant microalga Dunaliella salina under various phosphate regimes.

    Science.gov (United States)

    Wang, Ya; Zheng, Yanheng; Liu, Cong; Xu, Pingping; Li, Hao; Lin, Qiaoyun; Zhang, Chunhua; Ge, Ying

    2016-06-15

    Microalgae play an important role in arsenic (As) biogeochemical cycles as they are capable of accumulating and metabolizing this metalloid efficiently. This study aimed to investigate the toxicity, accumulation and transformation of arsenate (As(v)) in Dunaliella salina, an exceptionally halotolerant microalga, under various phosphate (PO4(3-)) regimes. The results of the 72-h toxicity test showed that D. salina was tolerant to As(v). In addition, the toxicity of As(v) was mitigated by an increased PO4(3-) supply. D. salina resisted the adverse effects of As(v) through the suppression of As uptake, enhancement of As reduction, methylation in the cell and excretion from the cell. Our study revealed that D. salina reduced As(v) toxicity using different strategies, i.e., reduction of As uptake upon acute As stress (24 h) and increase of As efflux following chronic As exposure (9 day). Moreover, PO4(3-) strongly affected the adsorption, uptake and transformation of As(v) in D. salina. As(v) reduction, DMA production and As excretion were enhanced under P-limited conditions (0.112 mg L(-1)) or upon higher As(v) exposure (1120 μg L(-1)). Furthermore, PO4(3-) had a significant influence on the As removal ability of D. salina. A high As removal efficiency (>95.6%) was observed in the 5-day cultures at an initial As concentration of 11.2 μg L(-1) and PO4(3-) of 0.112 and 1.12 mg L(-1). However, only 10.9% of total As was removed under 11.2 mg L(-1) PO4(3-) after 9 days of incubation. The findings of this study illustrate the pivotal roles of extracellular PO4(3-) in As(v) toxicity and metabolism, and the results may be relevant for future research on the minimization of As contamination in algal products as well as on the enhancement of As removal from the environment. PMID:27243670

  10. Obesity and respiratory diseases

    Directory of Open Access Journals (Sweden)

    Christopher Zammit

    2010-10-01

    Full Text Available Christopher Zammit, Helen Liddicoat, Ian Moonsie, Himender MakkerSleep and Ventilation Unit, Department of Respiratory Medicine, North Middlesex University Hospital, London, UKAbstract: The obesity epidemic is a global problem, which is set to increase over time. However, the effects of obesity on the respiratory system are often underappreciated. In this review, we will discuss the mechanical effects of obesity on lung physiology and the function of adipose tissue as an endocrine organ producing systemic inflammation and effecting central respiratory control. Obesity plays a key role in the development of obstructive sleep apnea and obesity hypoventilation syndrome. Asthma is more common and often harder to treat in the obese population, and in this study, we review the effects of obesity on airway inflammation and respiratory mechanics. We also discuss the compounding effects of obesity on chronic obstructive pulmonary disease (COPD and the paradoxical interaction of body mass index and COPD severity. Many practical challenges exist in caring for obese patients, and we highlight the complications faced by patients undergoing surgical procedures, especially given the increased use of bariatric surgery. Ultimately, a greater understanding of the effects of obesity on the respiratory disease and the provision of adequate health care resources is vital in order to care for this increasingly important patient population.Keywords: obesity, lung function, obstructive sleep apnea, obesity hypoventilation syndrome, anesthesia

  11. Respiratory muscle training increases respiratory muscle strength and reduces respiratory complications after stroke: a systematic review

    Directory of Open Access Journals (Sweden)

    Kênia KP Menezes

    2016-07-01

    Full Text Available Question: After stroke, does respiratory muscle training increase respiratory muscle strength and/or endurance? Are any benefits carried over to activity and/or participation? Does it reduce respiratory complications? Design: Systematic review of randomised or quasi-randomised trials. Participants: Adults with respiratory muscle weakness following stroke. Intervention: Respiratory muscle training aimed at increasing inspiratory and/or expiratory muscle strength. Outcome measures: Five outcomes were of interest: respiratory muscle strength, respiratory muscle endurance, activity, participation and respiratory complications. Results: Five trials involving 263 participants were included. The mean PEDro score was 6.4 (range 3 to 8, showing moderate methodological quality. Random-effects meta-analyses showed that respiratory muscle training increased maximal inspiratory pressure by 7 cmH2O (95% CI 1 to 14 and maximal expiratory pressure by 13 cmH2O (95% CI 1 to 25; it also decreased the risk of respiratory complications (RR 0.38, 95% CI 0.15 to 0.96 compared with no/sham respiratory intervention. Whether these effects carry over to activity and participation remains uncertain. Conclusion: This systematic review provided evidence that respiratory muscle training is effective after stroke. Meta-analyses based on five trials indicated that 30 minutes of respiratory muscle training, five times per week, for 5 weeks can be expected to increase respiratory muscle strength in very weak individuals after stroke. In addition, respiratory muscle training is expected to reduce the risk of respiratory complications after stroke. Further studies are warranted to investigate whether the benefits are carried over to activity and participation. Registration: PROSPERO (CRD42015020683. [Menezes KKP, Nascimento LR, Ada L, Polese JC, Avelino PR, Teixeira-Salmela LF (2016 Respiratory muscle training increases respiratory muscle strength and reduces respiratory

  12. Regulation of ribonucleotide reductase by Spd1 involves multiple mechanisms

    DEFF Research Database (Denmark)

    Nestoras, Konstantinos; Mohammed, Asma Hadi; Schreurs, Ann-Sofie; Fleck, Oliver; Watson, Adam T; Poitelea, Marius; O'Shea, Charlotte; Chahwan, Charly; Holmberg, Christian; Kragelund, Birthe B; Nielsen, Olaf; Osborne, Mark; Carr, Antony M; Liu, Cong

    2010-01-01

    The correct levels of deoxyribonucleotide triphosphates and their relative abundance are important to maintain genomic integrity. Ribonucleotide reductase (RNR) regulation is complex and multifaceted. RNR is regulated allosterically by two nucleotide-binding sites, by transcriptional control, and...

  13. Structural features of the ribonucleotide reductase of Aujeszky's disease virus.

    Science.gov (United States)

    Kaliman, A V; Boldogköi, Z; Fodor, I

    1994-01-01

    A gene construct of the Aujeszky's disease virus (ADV) genome was prepared and the DNA fragment encoding the ribonucleotide reductase was structurally characterized. We determined the entire DNA sequence of two adjacent open reading frames of the ribonucleotide reductase genes with the intergenic sequence of nine base pairs. From the sequence analysis we predict that Aujeszky's disease virus encodes a ribonucleotide reductase which comprises two polypeptides--large and small subunits, with sizes of 835 and 303 amino acids, respectively. Nucleotide and amino acid sequences of the large and small subunits of the Aujeszky's disease virus ribonucleotide reductase have been compared with that of other herpesviruses, and structural features of both proteins have been characterized. PMID:7810419

  14. Concentration and chemical status of arsenic in the blood of pregnant hamsters during critical embryogenesis. 1. Subchronic exposure to arsenate utilizing constant rate administration

    International Nuclear Information System (INIS)

    The concentration, availability, and chemical status of radiolabeled arsenic has been determined in the blood of pregnant hamsters at the beginning (morning of Day 8) and the end (morning of Day 9) of the critical period of embryogenesis. Hamster dams were exposed to teratogenic doses of arsenate by means of osmotic minipumps implanted on the morning of Day 6 of the gestation period. Whole blood arsenic concentrations were the same for 48 and 72 hr postimplant. The arsenic concentration of plasma equaled that of red cells. Plasma arsenic was not bound to macromolecules and had the same chemical status 48 and 72 hr postimplant. Arsenate was the dominant form (67% of the total). However, the presence of dimethylarsinic acid and arsenite indicates that the pentavalent species was metabolized. Red cell arsenic was bound to macromolecules in the cell sap. Seventy percent of red cell sap arsenic was dialyzable 48 hr postimplant, but only 56% 72 hr postimplant. Arsenate was the dominant dialyzable red cell species on Day 8 and arsenite was the major dialyzable form on Day 9. The authors findings demonstrate a relationship between the maternal blood concentration and chemical status of arsenic and the presence of malformations resulting from a constant rate exposure of pregnant hamsters to arsenate via the osmotic minipump

  15. SORPTION OF ARSENATE AND ARSENITE ON RUO2 X H2O: ANALYSIS OF SORBED PHASE OXIDATION STATE BY XANES IN ADVANCED PHOTON SOURCE ACTIVITY REPORT 2002

    Science.gov (United States)

    The sorption reactions of arsenate (As(V)) and arsenite (As(III)) on RuO2 x H2O were examined by X-ray Absorption Near Edge Spectroscopy (XANES) to elucidate the solid state speciation of sorbed As. At all pH values studied (pH 4-8), RuO2 x H

  16. Aldose reductase inhibitory activity and antioxidant capacity of pomegranate extracts

    OpenAIRE

    Karasu, Çimen; CUMAOĞLU, Ahmet; Gürpinar, Ali Rifat; Kartal, Murat; Kovacikova, Lucia; Milackova, Ivana; Stefek, Milan

    2012-01-01

    The pomegranate, Punica granatum L., has been the subject of current interest as a medicinal agent with wide-ranging therapeutic indications. In the present study, pomegranate ethanolic seed and hull extracts were tested, in comparison with a commercial sample, for the inhibition of aldose reductase, an enzyme involved in the etiology of diabetic complications. In vitro inhibition of rat lens aldose reductase was determined by a conventional method. Pomegranate ethanolic hull extract and comm...

  17. An overview on 5alpha-reductase inhibitors.

    Science.gov (United States)

    Aggarwal, Saurabh; Thareja, Suresh; Verma, Abhilasha; Bhardwaj, Tilak Raj; Kumar, Manoj

    2010-02-01

    Benign prostatic hyperplasia (BPH) is the noncancerous proliferation of the prostate gland associated with benign prostatic obstruction and lower urinary tract symptoms (LUTS) such as frequency, hesitancy, urgency, etc. Its prevalence increases with age affecting around 70% by the age of 70 years. High activity of 5alpha-reductase enzyme in humans results in excessive dihydrotestosterone levels in peripheral tissues and hence suppression of androgen action by 5alpha-reductase inhibitors is a logical treatment for BPH as they inhibit the conversion of testosterone to dihydrotestosterone. Finasteride (13) was the first steroidal 5alpha-reductase inhibitor approved by U.S. Food and Drug Administration (USFDA). In human it decreases the prostatic DHT level by 70-90% and reduces the prostatic size. Dutasteride (27) another related analogue has been approved in 2002. Unlike Finasteride, Dutasteride is a competitive inhibitor of both 5alpha-reductase type I and type II isozymes, reduced DHT levels >90% following 1 year of oral administration. A number of classes of non-steroidal inhibitors of 5alpha-reductase have also been synthesized generally by removing one or more rings from the azasteroidal structure or by an early non-steroidal lead (ONO-3805) (261). In this review all categories of inhibitors of 5alpha-reductase have been covered. PMID:19879888

  18. Binding of Fidarestat Stereoisomers with Aldose Reductase

    Directory of Open Access Journals (Sweden)

    Dae-Sil Lee

    2006-11-01

    Full Text Available The stereospecificity in binding to aldose reductase (ALR2 of two fidarestat {6-fluoro-2',5'-dioxospiro[chroman-4,4'-imidazolidine]-2-carboxamide} stereoisomers [(2S,4Sand (2R,4S] has been investigated by means of molecular dynamics simulations using freeenergy integration techniques. The difference in the free energy of binding was found to be2.0 ± 1.7 kJ/mol in favour of the (2S,4S-form, in agreement with the experimentalinhibition data. The relative mobilities of the fidarestats complexed with ALR2 indicate alarger entropic penalty for hydrophobic binding of (2R,4S-fidarestat compared to (2S,4S-fidarestat, partially explaining its lower binding affinity. The two stereoisomers differmainly in the orientation of the carbamoyl moiety with respect to the active site and rotationof the bond joining the carbamoyl substituent to the ring. The detailed structural andenergetic insights obtained from out simulations allow for a better understanding of thefactors determining stereospecific inhibitor-ALR2 binding in the EPF charges model.

  19. Aldose reductase inhibitory compounds from Xanthium strumarium.

    Science.gov (United States)

    Yoon, Ha Na; Lee, Min Young; Kim, Jin-Kyu; Suh, Hong-Won; Lim, Soon Sung

    2013-09-01

    As part of our ongoing search for natural sources of therapeutic and preventive agents for diabetic complications, we evaluated the inhibitory effects of components of the fruit of Xanthium strumarium (X. strumarium) on aldose reductase (AR) and galactitol formation in rat lenses with high levels of glucose. To identify the bioactive components of X. strumarium, 7 caffeoylquinic acids and 3 phenolic compounds were isolated and their chemical structures were elucidated on the basis of spectroscopic evidence and comparison with published data. The abilities of 10 X. strumarium-derived components to counteract diabetic complications were investigated by means of inhibitory assays with rat lens AR (rAR) and recombinant human AR (rhAR). From the 10 isolated compounds, methyl-3,5-di-O-caffeoylquinate showed the most potent inhibition, with IC₅₀ values of 0.30 and 0.67 μM for rAR and rhAR, respectively. In the kinetic analyses using Lineweaver-Burk plots of 1/velocity and 1/substrate, methyl-3,5-di-O-caffeoylquinate showed competitive inhibition of rhAR. Furthermore, methyl-3,5-di-O-caffeoylquinate inhibited galactitol formation in the rat lens and in erythrocytes incubated with a high concentration of glucose, indicating that this compound may be effective in preventing diabetic complications. PMID:23604720

  20. Aldose reductase mediates retinal microglia activation.

    Science.gov (United States)

    Chang, Kun-Che; Shieh, Biehuoy; Petrash, J Mark

    2016-04-29

    Retinal microglia (RMG) are one of the major immune cells in charge of surveillance of inflammatory responses in the eye. In the absence of an inflammatory stimulus, RMG reside predominately in the ganglion layer and inner or outer plexiform layers. However, under stress RMG become activated and migrate into the inner nuclear layer (INL) or outer nuclear layer (ONL). Activated RMG in cell culture secrete pro-inflammatory cytokines in a manner sensitive to downregulation by aldose reductase inhibitors. In this study, we utilized CX3CR1(GFP) mice carrying AR mutant alleles to evaluate the role of AR on RMG activation and migration in vivo. When tested on an AR(WT) background, IP injection of LPS induced RMG activation and migration into the INL and ONL. However, this phenomenon was largely prevented by AR inhibitors or in AR null mice, or was exacerbated in transgenic mice that over-express AR. LPS-induced increases in ocular levels of TNF-α and CX3CL-1 in WT mice were substantially lower in AR null mice or were reduced by AR inhibitor treatment. These studies demonstrate that AR expression in RMG may contribute to the proinflammatory phenotypes common to various eye diseases such as uveitis and diabetic retinopathy. PMID:27033597

  1. Microdistribution of chromated copper arsenate preservative in rubberwood (Hevea brasiliensis Muell. Arg.)

    Science.gov (United States)

    Jusoh, Ismail Bin

    2000-08-01

    Rubberwood is popular for making indoor furniture since rubberwood is relatively abundant and sustainable. Currently more than 60% of the total annual rubberwood produced by rubber plantation is used as fuelwood. Rubberwood has the potential for both indoor and outdoor application. For exterior applications, preservative treatment is needed to extend the service life of rubberwood. The objectives of this study are to (1) assess treatability of rubberwood with chromated copper arsenate (CCA) preservative, (2) evaluate the natural decay resistance and efficacy of CCA on rubberwood, and (3) study the microdistribution of CCA components in rubberwood cells. The treatability of rubberwood was determined by measuring the penetration and retention of CCA type C preservative after a full-cell treatment. Natural decay resistance and efficacy of CCA treatment on rubberwood was estimated using a laboratory soilblock test according to AWPA E 10-91. The microdistribution of chromium, copper and arsenic in CCA-treated rubberwood was studied using scanning electron microscope in conjunction with energy dispersive X-ray analyzer (SEM-EDXA). As expected, longitudinal permeability was found to be better than the radial and the tangential permeability. The penetration and retention in the radial direction was about 3 times better than in the tangential direction. Longer pressure period increased penetration and retention of CCA type C in rubberwood. Complete penetration was achieved after 4 hours of pressure (1240 kPa) treatment. A pre-treatment steaming improved the treatability of rubberwood regardless of the anatomical direction. The average weight loss by white rot and brown rot was about 1.5 times higher than that of soft rot. A linear relationship was found between the weight loss and the incubation period for all the six test fungi. A CCA retention of 4.1 kg/m3 reduced weight loss to about 10% and retention of 14.5 kg/m3 reduced the weight loss of all test fungi at less than 2

  2. Your Lungs and Respiratory System

    Science.gov (United States)

    ... Help White House Lunch Recipes Your Lungs & Respiratory System KidsHealth > For Kids > Your Lungs & Respiratory System Print A A A Text Size What's in ... your body, and they work with your respiratory system to allow you to take in fresh air, ...

  3. Climate change and respiratory disease: European Respiratory Society position statement.

    Science.gov (United States)

    Ayres, J G; Forsberg, B; Annesi-Maesano, I; Dey, R; Ebi, K L; Helms, P J; Medina-Ramón, M; Windt, M; Forastiere, F

    2009-08-01

    Climate change will affect individuals with pre-existing respiratory disease, but the extent of the effect remains unclear. The present position statement was developed on behalf of the European Respiratory Society in order to identify areas of concern arising from climate change for individuals with respiratory disease, healthcare workers in the respiratory sector and policy makers. The statement was developed following a 2-day workshop held in Leuven (Belgium) in March 2008. Key areas of concern for the respiratory community arising from climate change are discussed and recommendations made to address gaps in knowledge. The most important recommendation was the development of more accurate predictive models for predicting the impact of climate change on respiratory health. Respiratory healthcare workers also have an advocatory role in persuading governments and the European Union to maintain awareness and appropriate actions with respect to climate change, and these areas are also discussed in the position statement. PMID:19251790

  4. Conjugative plasmid in Corynebacterium flaccumfaciens subsp. oortii that confers resistance to arsenite, arsenate, and antimony(III)

    Energy Technology Data Exchange (ETDEWEB)

    Hendrick, C.A.; Haskins, W.P.; Vidaver, A.K.

    1984-07-01

    Gene transfer systems for phytopathogenic corynebacteria have not been reported previously. In this paper a conjugative 46-megadalton plasmid (pDG101) found in Corynebacterium flaccumfaciens subsp. oorii CO101 is described that mediates resistance to arsenite, arsenate, and antimony(III). Transfer of the plasmid from CO101 to four other strains from the C. flaccumfaciens group occurred between cells immobilized on nitrocellulose filters or on agar surfaces. Transconjugant strains expressed the same levels of metal resistance as the donor strain and were able to act as donor strains in subsequent matings. The physical presence of the plasmid was detected by agarose gel electrophoresis. Arsenite-sensitive derivatives of the donor and transconjugant strains were obtained after heat treatment; these were cured of pDG101.

  5. Transcripts of Anthocyanidin Reductase and Leucoanthocyanidin Reductase and Measurement of Catechin and Epicatechin in Tartary Buckwheat

    Directory of Open Access Journals (Sweden)

    Yeon Bok Kim

    2014-01-01

    Full Text Available Anthocyanidin reductase (ANR and leucoanthocyanidin reductase (LAR play an important role in the monomeric units biosynthesis of proanthocyanidins (PAs such as catechin and epicatechin in several plants. The aim of this study was to clone ANR and LAR genes involved in PAs biosynthesis and examine the expression of these two genes in different organs under different growth conditions in two tartary buckwheat cultivars, Hokkai T8 and T10. Gene expression was carried out by quantitative real-time RT-PCR, and catechin and epicatechin content was analyzed by high performance liquid chromatography. The expression pattern of ANR and LAR did not match the accumulation pattern of PAs in different organs of two cultivars. Epicatechin content was the highest in the flowers of both cultivars and it was affected by light in only Hokkai T8 sprouts. ANR and LAR levels in tartary buckwheat might be regulated by different mechanisms for catechin and epicatechin biosynthesis under light and dark conditions.

  6. Equine 5α-reductase activity and expression in epididymis.

    Science.gov (United States)

    Corbin, C J; Legacki, E L; Ball, B A; Scoggin, K E; Stanley, S D; Conley, A J

    2016-10-01

    The 5α-reductase enzymes play an important role during male sexual differentiation, and in pregnant females, especially equine species where maintenance relies on 5α-reduced progesterone, 5α-dihydroprogesterone (DHP). Epididymis expresses 5α-reductases but was not studied elaborately in horses. Epididymis from younger and older postpubertal stallions was divided into caput, corpus and cauda and examined for 5α-reductase activity and expression of type 1 and 2 isoforms by quantitative real-time polymerase chain reaction (qPCR). Metabolism of progesterone and testosterone to DHP and dihydrotestosterone (DHT), respectively, by epididymal microsomal protein was examined by thin-layer chromatography and verified by liquid chromatography tandem mass spectrometry (LC-MS/MS). Relative inhibitory potencies of finasteride and dutasteride toward equine 5α-reductase activity were investigated. Pregnenolone was investigated as an additional potential substrate for 5α-reductase, suggested previously from in vivo studies in mares but never directly examined. No regional gradient of 5α-reductase expression was observed by either enzyme activity or transcript analysis. Results of PCR experiments suggested that type 1 isoform predominates in equine epididymis. Primers for the type 2 isoform were unable to amplify product from any samples examined. Progesterone and testosterone were readily reduced to DHP and DHT, and activity was effectively inhibited by both inhibitors. Using epididymis as an enzyme source, no experimental evidence was obtained supporting the notion that pregnenolone could be directly metabolized by equine 5α-reductases as has been suggested by previous investigators speculating on alternative metabolic pathways leading to DHP synthesis in placenta during equine pregnancies. PMID:27466384

  7. Heliox reduces respiratory system resistance in respiratory syncytial virus induced respiratory failure

    NARCIS (Netherlands)

    Kneyber, Martin C. J.; van Heerde, Marc; Twisk, Jos W. R.; Plotz, Frans B.; Markhors, Dick G.

    2009-01-01

    Introduction Respiratory syncytial virus (RSV) lower respiratory tract disease is characterised by narrowing of the airways resulting in increased airway resistance, air-trapping and respiratory acidosis. These problems might be overcome using helium-oxygen gas mixture. However, the effect of mechan

  8. Electrode assemblies composed of redox cascades from microbial respiratory electron transfer chains

    Energy Technology Data Exchange (ETDEWEB)

    Gates, Andrew J. [Univ. of East Anglia, Norwich (United Kingdom); Marritt, Sophie [Univ. of East Anglia, Norwich (United Kingdom); Bradley, Justin [Univ. of East Anglia, Norwich (United Kingdom); Shi, Liang [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McMillan, Duncan G. [Univ. of Leeds (United Kingdom); Jeuken, Lars J. [Univ. of Leeds (United Kingdom); Richardson, David [Univ. of East Anglia, Norwich (United Kingdom); Butt, Julea N. [Univ. of East Anglia, Norwich (United Kingdom)

    2013-10-01

    Respiratory and photosynthetic electron transfer chains are dependent on vectorial electron transfer through a series of redox proteins. Examples include electron transfer from NapC to NapAB nitrate reductase in Paracoccus denitrificans and from CymA to Fcc3 (flavocytochrome c3) fumarate reductase in Shewanella oneidensis MR-1. In the present article, we demonstrate that graphite electrodes can serve as surfaces for the stepwise adsorption of NapC and NapAB, and the stepwise adsorption of CymA and Fcc3. Aspects of the catalytic properties of these assemblies are different from those of NapAB and Fcc3 adsorbed in isolation. We propose that this is due to the formation of NapC-NapAB and of CymA-Fcc3 complexes that are capable of supporting vectorial electron transfer.

  9. The role of biliverdin reductase in colorectal cancer

    International Nuclear Information System (INIS)

    In recent years, the effects of biliverdin and bilirubin have been studied extensively, and an inhibitory effect of bile pigments in cancer progression has been proposed. In this study we focused on the effects of biliverdin reductase, the enzyme that converts biliverdin to bilirubin, in colorectal cancer. For in vitro experiments we used a human colorectal carcinoma cell line and transfected it with an expression construct of shRNA specific for biliverdin reductase, to create cells with stable knock-down of enzyme expression. Cell proliferation was analyzed using the CASY model TT cell counting device. Western blot protein analysis was performed to study intracellular signaling cascades. Samples of human colorectal cancer were analyzed using immunohistochemistry. We were able to confirm the antiproliferative effects of bile pigments on cancer cells in vitro. However, this effect was attenuated in biliverdin reductase knock down cells. ERK and Akt activation seen under biliverdin and bilirubin treatment was also reduced in biliverdin reductase deficient cells. Immunohistochemical analysis of tumor samples from patients with colorectal cancer showed elevated biliverdin reductase levels. High enzyme expression was associated with lower overall and disease free patient survival. We conclude that BVR is required for bile pigment mediated effects regarding cancer cell proliferation and modulation of intracellular signaling cascades. The role of BVR overexpression in vivo and its exact influence on cancer progression and patient survival need to be further investigated. (author)

  10. Adult respiratory distress syndrome

    International Nuclear Information System (INIS)

    Due to improved emergency resuscitation procedures, and with advancing medical technology in the field of critical care, an increasing number of patients survive the acute phase of shock and catastrophic trauma. Patients who previously died of massive sepsis, hypovolemic or hypotensive shock, multiple fractures, aspiration, toxic inhalation, and massive embolism are now surviving long enough to develop previously unsuspected and unrecognized secondary effects. With increasing frequency, clinicians are recognizing the clinical and radiographic manifestations of pathologic changes in the lungs occurring secondary to various types of massive insult. This paper gives a list of diseases that have been shown to precipitate or predispose to diffuse lung damage. Various terms have been used to describe the lung damage and respiratory failure secondary to these conditions. The term adult respiratory distress syndrome (ARDS) is applied to several cases of sudden respiratory failure in patients with previously healthy lungs following various types of trauma or shock. Numerous investigations and experiments have studied the pathologic changes in ARDS, and, while there is still no clear indication of why it develops, there is now some correlation of the sequential pathologic developments with the clinical and radiographic changes

  11. Nanotechnology in respiratory medicine.

    Science.gov (United States)

    Omlor, Albert Joachim; Nguyen, Juliane; Bals, Robert; Dinh, Quoc Thai

    2015-01-01

    Like two sides of the same coin, nanotechnology can be both boon and bane for respiratory medicine. Nanomaterials open new ways in diagnostics and treatment of lung diseases. Nanoparticle based drug delivery systems can help against diseases such as lung cancer, tuberculosis, and pulmonary fibrosis. Moreover, nanoparticles can be loaded with DNA and act as vectors for gene therapy in diseases like cystic fibrosis. Even lung diagnostics with computer tomography (CT) or magnetic resonance imaging (MRI) profits from new nanoparticle based contrast agents. However, the risks of nanotechnology also have to be taken into consideration as engineered nanomaterials resemble natural fine dusts and fibers, which are known to be harmful for the respiratory system in many cases. Recent studies have shown that nanoparticles in the respiratory tract can influence the immune system, can create oxidative stress and even cause genotoxicity. Another important aspect to assess the safety of nanotechnology based products is the absorption of nanoparticles. It was demonstrated that the amount of pulmonary nanoparticle uptake not only depends on physical and chemical nanoparticle characteristics but also on the health status of the organism. The huge diversity in nanotechnology could revolutionize medicine but makes safety assessment a challenging task. PMID:26021823

  12. [Respiratory preparation before surgery in patients with chronic respiratory failure].

    Science.gov (United States)

    Delay, Jean-Marc; Jaber, Samir

    2012-03-01

    Scheduled and/or thoracic, abdominal surgeries increase the risk of respiratory postoperative complications. In patients with chronic respiratory failure, preoperative evaluation should be performed to evaluate respiratory function in aim to optimize perioperative management. Preoperative gas exchange abnormalities (hypoxemia or hypercapnia) are associated with respiratory postoperative complications. Respiratory physiotherapy and prophylactic non-invasive ventilation should be integrated in a global rehabilitation management for cardiothoracic or abdominal surgery procedures, which are at high risk of postoperative respiratory dysfunction. Stopping tobacco consummation should be benefit, but decease risk of postoperative complications is relevant only after a period for 6 to 8 weeks of cessation. Bronchodilatator aerosol therapy (beta-agonists and atropinics) and inhaled corticotherapy allow a rapid preparation for 24 to 48 h. Systematic preoperative antibiotherapy should not be recommended. PMID:22004791

  13. Intramolecular electron transfer in Pseudomonas aeruginosa cd(1) nitrite reductase

    DEFF Research Database (Denmark)

    Farver, Ole; Brunori, Maurizio; Cutruzzolà, Francesca;

    2009-01-01

    The cd(1) nitrite reductases, which catalyze the reduction of nitrite to nitric oxide, are homodimers of 60 kDa subunits, each containing one heme-c and one heme-d(1). Heme-c is the electron entry site, whereas heme-d(1) constitutes the catalytic center. The 3D structure of Pseudomonas aeruginosa...... nitrite reductase has been determined in both fully oxidized and reduced states. Intramolecular electron transfer (ET), between c and d(1) hemes is an essential step in the catalytic cycle. In earlier studies of the Pseudomonas stutzeri enzyme, we observed that a marked negative cooperativity is...... controlling this internal ET step. In this study we have investigated the internal ET in the wild-type and His369Ala mutant of P. aeruginosa nitrite reductases and have observed similar cooperativity to that of the Pseudomonas stutzeri enzyme. Heme-c was initially reduced, in an essentially diffusion...

  14. Respiratory Syncytial Virus in Lower Respiratory Tract Infections

    OpenAIRE

    Anita Chakravarti; Bineeta Kashyap

    2007-01-01

    Objective: Acute lower respiratory infections lead to high morbidity and mortality rates in children from developing countries. The aim of this study was to look into the extent of respiratory syncytial virus infections in children with special reference to the role of specific immunoglobulins in protection against infection as well as the association with bacterial pathogens. Material & Methods: Nasopharyngeal aspirates were tested for respiratory syncytial virus antigen by enzyme immunoassa...

  15. Aldo keto reductases 1B in endocrinology and metabolism

    Directory of Open Access Journals (Sweden)

    AntoineMartinez

    2012-08-01

    Full Text Available The aldose reductase (human AKR1B1/mouse Akr1b3 has been the focus of many research because of its role in diabetic complications. The starting point of these alterations is the massive entry of glucose in polyol pathway where it is converted into sorbitol by this enzyme. However, the issue of aldose reductase function in non-diabetic condition remains unresolved. Aldose reductase-like enzymes (AKR1B10, Akr1b7 and Akr1b8 are highly related isoforms often co-expressed with bona fide aldose reductase, making functional analysis of one or the other isoform a challenging task. AKR1B/Akr1b members share at least 65% protein identity and the general ability to reduce many redundant substrates such as aldehydes provided from lipid peroxidation, steroids and their by-products and xenobiotics in vitro. Based on these properties, AKR1B/Akr1b are generally considered as detoxifying enzymes. Considering that divergences should be more informative than similarities to help understanding their physiological functions, we chose to review specific hallmarks of each human/mouse isoforms by focusing on tissue distribution and specific mechanisms of gene regulation. Indeed, although the aldose reductase shows ubiquitous expression, aldose reductase-like proteins exhibit tissue-specific patterns of expression. We focused on 3 organs where certain isoforms are enriched, the adrenal gland, enterohepatic and adipose tissues and tried to connect recent enzymatic and regulation data with endocrine and metabolic functions of these organs. We presented recent mouse models showing unsuspected physiological functions in the regulation of glucido-lipidic metabolism and adipose tissue homeostasis. Beyond the widely accepted idea that AKR1B/Akr1b are detoxification enzymes, these recent reports provide growing evidences that they are able to modify or generate signal molecules. This conceptually shifts this class of enzymes from unenviable status of scavenger to upper class of

  16. Expression and site-directed mutagenesis of human dihydrofolate reductase

    International Nuclear Information System (INIS)

    A procaryotic high-level expression vector for human dihydrofolate reductase has been constructed and the protein characterized as a first step toward structure-function studies of this enzyme. A vector bearing the tac promoter, four synthetic oligodeoxynucleotides, and a restriction fragment from the dihydrofolate reductase cDNA were ligated in a manner which optimized the transcriptional and translational frequency of the enzyme mRNA. The reductase, comprising ca. 17% of the total soluble protein in the host bacteria, was purified to apparent homogeneity as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and characterized by amino acid composition, partial amino acid sequence, and steady-sate kinetic analysis. This expression vector has been used as a template for double-stranded plasmid DNA site-specific mutagenesis. Functional studies on a Cys-6 → Ser-6 mutant enzyme support the contention that Cys-6 is obligatory for organomercurial activation of human dihydrofolate reductase. The Ser-6 mutant enzyme was not activated to any extent following a 24-h incubation with p-(hydroxymercuri)benzoate and nicotinamide adenine dinucleotide phosphate (reduced) (NADPH), whereas the k/sub cat/ for Cys-6 reductase increased 2-fold under identical conditions. The specific activities of the Cys-6 and Ser-6 enzymes were virtually identical as determined by methotrexate titration as were the K/sub m/ values for both dihydrofolate and NADPH. The Ser-6 mutant showed a decreased temperature stability and was more sensitive to inactivation by α-chymotrypsin when compared to the wild-type enzyme. These results suggest that the Ser-6 mutant reductase is conformationally altered relative to the Cys-6 native enzyme

  17. Effect of vanadium on nitrate reductase activity in tomato leaves

    OpenAIRE

    J. Buczek

    2015-01-01

    The activity of nitrate reductase in cell-free extracts from tomato leaves is completely inhibited by 100 μM NaVO3 or VOCl2. In experiments in vivo vanadium ions inhibit the activity of the enzyme in 50 to 60 per cent. Addition of l mM vanadium to the medium on which tomato seedlings are grown causes after 24 h almost complete inhibition of nitrate reductase activity in cell-free extracts of the enzyme. Inhibition with vanadium may be abolished in experiments in vitro if the extract is treate...

  18. The intramolecular electron transfer between copper sites of nitrite reductase

    DEFF Research Database (Denmark)

    Farver, O; Eady, R R; Abraham, Z H;

    1998-01-01

    The intramolecular electron transfer (ET) between the type 1 Cu(I) and the type 2 Cu(II) sites of Alcaligenes xylosoxidans dissimilatory nitrite reductase (AxNiR) has been studied in order to compare it with the analogous process taking place in ascorbate oxidase (AO). This internal process is......(I) and the trinuclear copper centre in ascorbate oxidase, and the characteristics of the internal ET processes of these enzymes are compared. The data are consistent with the faster ET observed in nitrite reductase arising from a more advantageous entropy of activation when compared with ascorbate...

  19. Artificial electron donors for nitrate and nitrite reductases usable as mediators in amperometric biosensors

    Energy Technology Data Exchange (ETDEWEB)

    Strehlitz, B. (Umweltforschungszentrum Leipzig-Halle GmbH, Leipzig (Germany)); Gruendig, B. (Institut fuer Chemo- und Biosensorik, Muenster-Roxel (Germany)); Vorlop, K.D. (Bundesforschungsanstalt fuer Landwirtschaft, Braunschweig (Germany). Inst. fuer Technologie); Bartholmes, P. (Witten-Herdecke Univ., Witten (Germany). Inst. fuer Biochemie); Kotte, H. (Umweltforschungszentrum Leipzig-Halle GmbH, Leipzig (Germany)); Stottmeister, U. (Umweltforschungszentrum Leipzig-Halle GmbH, Leipzig (Germany))

    1994-07-01

    Various nitrate and nitrite reductases are capable of accepting electrons from artificial donors. Combining these redox active donors with an amperometric redox electrode which is covered with an immobilized layer of such a nitrate or nitrite reductase, new enzyme sensors can be created for the detection of nitrate or nitrite, respectively. A range of suitable electron donors for nitrate reductases and nitrite reductase from different sources have been selected and characterized by electrochemical methods. (orig.)

  20. Respiratory failure in diabetic ketoacidosis

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    Respiratory failure complicating the course of diabeticketoacidosis (DKA) is a source of increased morbidityand mortality. Detection of respiratory failure in DKA requiresfocused clinical monitoring, careful interpretationof arterial blood gases, and investigation for conditionsthat can affect adversely the respiration. Conditions thatcompromise respiratory function caused by DKA can bedetected at presentation but are usually more prevalentduring treatment. These conditions include deficits ofpotassium, magnesium and phosphate and hydrostatic ornon-hydrostatic pulmonary edema. Conditions not causedby DKA that can worsen respiratory function under theadded stress of DKA include infections of the respiratorysystem, pre-existing respiratory or neuromuscular diseaseand miscellaneous other conditions. Prompt recognitionand management of the conditions that can lead torespiratory failure in DKA may prevent respiratory failureand improve mortality from DKA.

  1. Stability of arsenate-bearing Fe(III)/Al(III) co-precipitates in the presence of sulfide as reducing agent under anoxic conditions.

    Science.gov (United States)

    Doerfelt, Christoph; Feldmann, Thomas; Roy, Ranjan; Demopoulos, George P

    2016-05-01

    Currently, the co-precipitation of arsenate with ferric iron at molar ratios Fe(III)/As(V) ≥ 3 by lime neutralization produces tailings solids that are stable under oxic conditions. However not much is known about the stability of these hazardous co-precipitates under anoxic conditions. These can develop in tailings storage sites by the action of co-discharged reactive sulfides, organic reagent residuals or bacterial activity. The ferric matrix can then undergo reductive dissolution reactions, which could release arsenic into the pore water. Co-ions like aluminum could provide a redox-immune sink to scavenge any mobilized arsenic as a result of reduction of ferric. As such, in this work Fe(III)/As(V) = 4 and aluminum substituted Fe(III)/Al(III)/As(V) = 2/2/1 co-precipitates were produced in a mini continuous co-precipitation process circuit and subjected to excess sulfide addition under inert gas to evaluate their stability. It was found that the ferric-arsenate co-precipitate could retain up to 99% (30 mg/L in solution) of its arsenic content despite the high pH (10.5) and extremely reducing (Eh < -200 mV) environment. There was no significant reduction of arsenate and only 45% of ferric iron was reduced. Partial aluminum substitution was found to cut the amount of mobilized arsenic by 50% (down to 15 mg/L) hence mixed Fe(III)/Al(III)-arsenate co-precipitates may offer better resistance to reductive destabilization over the long term than all iron co-precipitates. PMID:26950022

  2. Paediatric respiratory infections

    Directory of Open Access Journals (Sweden)

    Mark L. Everard

    2016-03-01

    Full Text Available Pulmonary infections remain a major cause of infant and child mortality worldwide and are responsible for a substantial burden of morbidity. During the 2015 European Respiratory Society International Congress in Amsterdam, some of the main findings from peer-reviewed articles addressing this topic that were published in the preceding 12 months were reviewed in a Paediatric Clinical Year in Review session. The following article highlights some of the insights provided by these articles into the complex interactions of the human host with the extensive and dynamic populations of microorganisms that call an individual “home”.

  3. Respiratory System Disease.

    Science.gov (United States)

    Goetz, Danielle M; Singh, Shipra

    2016-08-01

    Respiratory system involvement in cystic fibrosis is the leading cause of morbidity and mortality. Defects in the cystic fibrosis transmembrane regulator (CFTR) gene throughout the sinopulmonary tract result in recurrent infections with a variety of organisms including Pseudomonas aeruginosa, methicillin-resistant Staphylococcus aureus, and nontuberculous mycobacteria. Lung disease occurs earlier in life than once thought and ideal methods of monitoring lung function, decline, or improvement with therapy are debated. Treatment of sinopulmonary disease may include physiotherapy, mucus-modifying and antiinflammatory agents, antimicrobials, and surgery. In the new era of personalized medicine, CFTR correctors and potentiators may change the course of disease. PMID:27469180

  4. Recurrent respiratory papillomatosis.

    Science.gov (United States)

    Venkatesan, Naren N; Pine, Harold S; Underbrink, Michael P

    2012-06-01

    Recurrent respiratory papillomatosis (RRP) is a rare, benign disease with no known cure. RRP is caused by infection of the upper aerodigestive tract with the human papillomavirus (HPV). Passage through the birth canal is thought to be the initial transmission event, but infection may occur in utero. HPV vaccines have helped to provide protection from cervical cancer; however, their role in the prevention of RRP is undetermined. Clinical presentation of initial symptoms of RRP may be subtle. RRP course varies, and current management focuses on surgical debulking of papillomatous lesions with or without concurrent adjuvant therapy. PMID:22588043

  5. Respiratory tract and mediastinum

    International Nuclear Information System (INIS)

    Respiratory tract problems originating in attempts to diagnose and treat illness are commonplace. They range from pharyngeal trauma during intubation to radiation-induced thyroid carcinoma. Occasionally, as with pulmonary hypervolemia accompanying drug-induced renal failure, they originate at a distance. Their actual number far exceeds those brought to clinical attention. Familiarity with the procedures which give rise to these complications is helpful in detecting and remedying them. It is important, therefore, to discuss their pathogenesis as well as their clinical and radiological findings

  6. Current devices of respiratory physiotherapy

    OpenAIRE

    Hristara-Papadopoulou, A; Tsanakas, J; Diomou, G; Papadopoulou, O.

    2008-01-01

    In recent years patients with respiratory diseases use various devices, which help the removal of mucus from the airways and the improvement of pulmonary function. The aim of the present study is to determine the effectiveness of the current devices of respiratory physiotherapy, as it comes from the review of literature. The current devices of physiotherapy for patients with respiratory diseases, are presented as an alternative therapy method or a supplemental therapy and they can motivate pa...

  7. Auscultation of the respiratory system

    OpenAIRE

    2015-01-01

    Auscultation of the lung is an important part of the respiratory examination and is helpful in diagnosing various respiratory disorders. Auscultation assesses airflow through the trachea-bronchial tree. It is important to distinguish normal respiratory sounds from abnormal ones for example crackles, wheezes, and pleural rub in order to make correct diagnosis. It is necessary to understand the underlying pathophysiology of various lung sounds generation for better understanding of disease proc...

  8. Respiratory failure in diabetic ketoacidosis

    OpenAIRE

    Konstantinov, Nikifor K; Rohrscheib, Mark; Agaba, Emmanuel I.; Dorin, Richard I.; Murata, Glen H.; Tzamaloukas, Antonios H.

    2015-01-01

    Respiratory failure complicating the course of diabetic ketoacidosis (DKA) is a source of increased morbidity and mortality. Detection of respiratory failure in DKA requires focused clinical monitoring, careful interpretation of arterial blood gases, and investigation for conditions that can affect adversely the respiration. Conditions that compromise respiratory function caused by DKA can be detected at presentation but are usually more prevalent during treatment. These conditions include de...

  9. Inhibition of Albendazole and Oxfendazole on the Activity of Fumaric Reductase in Cysticercus cellulosae

    Institute of Scientific and Technical Information of China (English)

    GAO Xue-jun; LI Qing-zhang; LI Xia

    2004-01-01

    The activity of fumaric reductase in Cysticercus cellulosae tissue homogenate with albendazole and oxfendazole individually was detected. Results showed that the two kinds of drugs both could inhabite the activity of fumaric reductase. The results indicate that the mechanism of action of benzimidazole carbamate drugs is probably inhabiting the complex of fumaric reductase noncompetently, thus lead to the exhaostion of energy and death.

  10. Management of Postoperative Respiratory Failure.

    Science.gov (United States)

    Mulligan, Michael S; Berfield, Kathleen S; Abbaszadeh, Ryan V

    2015-11-01

    Despite best efforts, postoperative complications such as postoperative respiratory failure may occur and prompt recognition of the process and management is required. Postoperative respiratory failure, such as postoperative pneumonia, postpneumonectomy pulmonary edema, acute respiratory distress-like syndromes, and pulmonary embolism, are associated with high morbidity and mortality. The causes of these complications are multifactorial and depend on preoperative, intraoperative, and postoperative factors, some of which are modifiable. The article identifies some of the risk factors, causes, and treatment strategies for successful management of the patient with postoperative respiratory failure. PMID:26515943

  11. Submersion and acute respiratory failure

    Directory of Open Access Journals (Sweden)

    Yu-Jang Su

    2014-01-01

    Conclusions: Submersion patients who are hypothermic on arrival of emergency department (ED are risky to respiratory failure and older, more hypothermic, longer hospital stay in suicidal submersion patients.

  12. Separation/Preconcentration and Speciation Analysis of Trace Amounts of Arsenate and Arsenite in Water Samples Using Modified Magnetite Nanoparticles and Molybdenum Blue Method

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Karimi

    2014-01-01

    Full Text Available A new, simple, and fast method for the separation/preconcentration and speciation analysis of arsenate and arsenite ions using cetyltrimethyl ammonium bromide immobilized on alumina-coated magnetite nanoparticles (CTAB@ACMNPs followed by molybdenum blue method is proposed. The method is based on the adsorption of arsenate on CTAB@ACMNPs. Total arsenic in different samples was determined as As(V after oxidation of As(III to As(V using potassium permanganate. The arsenic concentration has been determined by UV-Visible spectrometric technique based on molybdenum blue method and amount of As(III was calculated by subtracting the concentration of As(V from total arsenic concentration. MNPs and ACMNPs were characterized by VSM, XRD, SEM, and FT-IR spectroscopy. Under the optimal experimental conditions, the preconcentration factor, detection limit, linear range, and relative standard deviation (RSD of arsenate were 175 (for 350 mL of sample solution, 0.028 μg mL−1, 0.090–4.0 μg mL−1, and 2.8% (for 2.0 μg mL−1, n=7, respectively. This method avoided the time-consuming column-passing process of loading large volume samples in traditional SPE through the rapid isolation of CTAB@ACMNPs with an adscititious magnet. The proposed method was successfully applied to the determination and speciation of arsenic in different water samples and suitable recoveries were obtained.

  13. Respiratory symptoms of megaesophagus

    Directory of Open Access Journals (Sweden)

    Fabio Di Stefano

    2013-03-01

    Full Text Available Megaesophagus as the end result of achalasia is the consequence of disordered peristalsis and the slow decompensation of the esophageal muscular layer. The main symptoms of achalasia are dysphagia, regurgitation, chest pain and weight loss, but respiratory symptoms, such as coughing, particularly when patients lie in a horizontal position, may also be common due to microaspiration. A 70-year old woman suffered from a nocturnal cough and shortness of breath with stridor. She reported difficulty in swallowing food over the past ten years, but had adapted by eating a semi-liquid diet. Chest X-ray showed right hemithorax patchy opacities projecting from the posterior mediastinum. Chest computed tomography scan showed a marked dilatation of the esophagus with abundant food residues. Endoscopy confirmed the diagnosis of megaesophagus due to esophageal achalasia, excluding other causes of obstruction, such as secondary esophagitis, polyps, leiomyoma or leiomyosarcoma. In the elderly population, swallowing difficulties due to esophageal achalasia are often underestimated and less troublesome than the respiratory symptoms that are caused by microaspiration. The diagnosis of esophageal achalasia, although uncommon, should be considered in patients with nocturnal chronic coughs and shortness of breath with stridor when concomitant swallowing difficulties are present.

  14. Heliox reduces respiratory system resistance in respiratory syncytial virus induced respiratory failure

    OpenAIRE

    Kneijber, M.C.J.; Heerde, van, H.J.W; Twisk, J W R; Plotz, F.; Markhorst, D.G.

    2009-01-01

    Introduction Respiratory syncytial virus (RSV) lower respiratory tract disease is characterised by narrowing of the airways resulting in increased airway resistance, air-trapping and respiratory acidosis. These problems might be overcome using helium-oxygen gas mixture. However, the effect of mechanical ventilation with heliox in these patients is unclear. The objective of this prospective cross-over study was to determine the effects of mechanical ventilation with heliox 60/40 versus convent...

  15. Sepiapterin reductase deficiency an autosomal recessive DOPA-responsive dystonia

    NARCIS (Netherlands)

    N.G. Abeling; M. Duran; H.D. Bakker; L. Stroomer; B. Thony; N. Blau; J. Booij; B.T. Poll-The

    2006-01-01

    The diagnosis of a 14-year-old girl with a new homoallelic mutation in the sepiapterin reductase (SR) gene is reported. Initially she presented at the age of 2 with hypotonia and mild cognitive developmental delay, and was diagnosed as having mild methylmalonic aciduria, which was recently identifie

  16. Thioredoxin and NADP-thioredoxin reductase from cultured carrot cells

    Science.gov (United States)

    Johnson, T. C.; Cao, R. Q.; Kung, J. E.; Buchanan, B. B.

    1987-01-01

    Dark-grown carrot (Daucus carota L.) tissue cultures were found to contain both protein components of the NADP/thioredoxin system--NADP-thioredoxin reductase and the thioredoxin characteristic of heterotrophic systems, thioredoxin h. Thioredoxin h was purified to apparent homogeneity and, like typical bacterial counterparts, was a 12-kdalton (kDa) acidic protein capable of activating chloroplast NADP-malate dehydrogenase (EC 1.1.1.82) more effectively than fructose-1,6-bisphosphatase (EC 3.1.3.11). NADP-thioredoxin reductase (EC 1.6.4.5) was partially purified and found to be an arsenite-sensitive enzyme composed of two 34-kDa subunits. Carrot NADP-thioredoxin reductase resembled more closely its counterpart from bacteria rather than animal cells in acceptor (thioredoxin) specificity. Upon greening of the cells, the content of NADP-thioredoxin-reductase activity, and, to a lesser extent, thioredoxin h decreased. The results confirm the presence of a heterotrophic-type thioredoxin system in plant cells and raise the question of its physiological function.

  17. Bidirectional catalysis by copper-containing nitrite reductase

    NARCIS (Netherlands)

    Wijma, HJ; Canters, GW; de Vries, S; Verbeet, MP

    2004-01-01

    The copper-containing nitrite reductase from Alcaligenes faecalis S-6 was found to catalyze the oxidation of nitric oxide to nitrite, the reverse of its physiological reaction. Thermodynamic and kinetic constants with the physiological electron donor pseudoazurin were determined for both directions

  18. Thioredoxin reductase from s. Coelicolor as a drug target

    Czech Academy of Sciences Publication Activity Database

    Koháryová, M.; Brynda, Jiří; Řezáčová, Pavlína; Kollárová, M.

    2015-01-01

    Roč. 282, Suppl 1 (2015), s. 396. ISSN 1742-464X. [Congress of the Federation of European Biochemical Societies (FEBS) - The Biochemical Basis of Life /40./. 04.07.2015-09.07.2015, Berlin] Institutional support: RVO:61388963 ; RVO:68378050 Keywords : thioredoxin reductase * protein structure * drugs Subject RIV: CE - Biochemistry

  19. Isolation and expression of the Pneumocystis carinii dihydrofolate reductase gene

    DEFF Research Database (Denmark)

    Edman, J C; Edman, U; Cao, Mi-Mi;

    1989-01-01

    Pneumocystis carinii dihydrofolate reductase (DHFR; 5,6,7,8-tetrahydrofolate: NADP+ oxidoreductase, EC 1.5.1.3) cDNA sequences have been isolated by their ability to confer trimethoprim resistance to Escherichia coli. Consistent with the recent conclusion that P. carinii is a member of the Fungi...

  20. Fatty Acyl-CoA Reductase 1 Deficiency

    Directory of Open Access Journals (Sweden)

    Charles N Swisher

    2015-01-01

    Full Text Available Investigators from Erlangen, Germany; Calgary, CA; and Kafranbel, Syria, identified mutations in the gene, fatty acyl-CoA reductase 1 (FAR1 deficiency, adding to three other genes involved in plasmalogen biosynthesis, in two families affected by severe intellectual disability, early-onset epilepsy, microcephaly, congenital cataracts, growth retardation, and spasticity.

  1. Implementing change in respiratory care.

    Science.gov (United States)

    Stoller, James K

    2010-06-01

    Though people are generally averse to change, change and innovation are critically important in respiratory care to maintain scientific and clinical progress. This paper reviews the issue of change in respiratory care. I summarize several available models of organizational and personal change (ie, those of Kotter and of Silversin and Kornacki, and the Intentional Change Theory of Boyatzis), review the characteristics of change-avid respiratory therapy departments, offer an example of a change effort in respiratory care (implementation of respiratory care protocols) and then analyze this change effort as it took place at one institution, the Cleveland Clinic, using these models. Finally, I present the results of an analysis of change-avid respiratory therapy departments and offer some suggestions regarding change management for the profession and for individual respiratory care clinicians. Common features of theories of organizational change include developing a sense of urgency, overcoming resistance, developing a guiding coalition, and involving key stakeholders early. With the understanding that change efforts may seem unduly "clean" and orderly in retrospect, the models help explain the sustainable success of efforts to implement the Respiratory Therapy Consult Service at the Cleveland Clinic. By implication, these models offer value in planning change efforts prospectively. Further analysis of features of change-avid respiratory therapy departments indicates 11 highly desired features, of which four that especially characterize change-avid departments include: having an up-to-date leadership team; employee involvement in change; celebrating wins; and an overall sense of progressiveness in the department. This analysis suggests that understanding and embracing change is important. To anchor change in our profession, greater attention should be given to developing a pipeline of respiratory care clinicians who, by virtue of their advanced training, have the skills

  2. Crystal structures of pinoresinol-lariciresinol and phenylcoumaran benzylic ether reductases and their relationship to isoflavone reductases

    Science.gov (United States)

    Min, Tongpil; Kasahara, Hiroyuki; Bedgar, Diana L.; Youn, Buhyun; Lawrence, Paulraj K.; Gang, David R.; Halls, Steven C.; Park, HaJeung; Hilsenbeck, Jacqueline L.; Davin, Laurence B.; Lewis, Norman G.; Kang, ChulHee

    2003-01-01

    Despite the importance of plant lignans and isoflavonoids in human health protection (e.g. for both treatment and prevention of onset of various cancers) as well as in plant biology (e.g. in defense functions and in heartwood development), systematic studies on the enzymes involved in their biosynthesis have only recently begun. In this investigation, three NADPH-dependent aromatic alcohol reductases were comprehensively studied, namely pinoresinol-lariciresinol reductase (PLR), phenylcoumaran benzylic ether reductase (PCBER), and isoflavone reductase (IFR), which are involved in central steps to the various important bioactive lignans and isoflavonoids. Of particular interest was in determining how differing regio- and enantiospecificities are achieved with the different enzymes, despite each apparently going through similar enone intermediates. Initially, the three-dimensional x-ray crystal structures of both PLR_Tp1 and PCBER_Pt1 were solved and refined to 2.5 and 2.2 A resolutions, respectively. Not only do they share high gene sequence similarity, but their structures are similar, having a continuous alpha/beta NADPH-binding domain and a smaller substrate-binding domain. IFR (whose crystal structure is not yet obtained) was also compared (modeled) with PLR and PCBER and was deduced to have the same overall basic structure. The basis for the distinct enantio-specific and regio-specific reactions of PCBER, PLR, and IFR, as well as the reaction mechanism and participating residues involved (as identified by site-directed mutagenesis), are discussed.

  3. Retention of arsenate using genetically modified coryneform bacteria and determination of arsenic in solid samples by ICP-MS.

    Science.gov (United States)

    Villadangos, A F; Ordóñez, E; Muñoz, M I; Pastrana, I M; Fiuza, M; Gil, J A; Mateos, L M; Aller, A J

    2010-01-15

    A novel method for the retention of arsenate [As(V)] combining time-controlled solid-phase extraction with living bacterial biomass is presented. As(V) retention was carried out by exposing the extractant, consisting of a living double-mutant of Corynebacterium glutamicum strain ArsC1-C2, to the sample for a retention time of 1-7min, before the arsenic distribution equilibrium between the sample solution and the extractant was established. The amount of As(V) retained in the biomass was measured by inductively coupled plasma-mass spectrometry (ICP-MS) after the sample had been treated with nitric acid. A theoretical model of the retention process was developed to describe the experimental retention-time profiles obtained with the bacterial cells. This relationship provided a feasible quantification of the retention process before steady-state was reached, providing that the agitation conditions and the retention time had been controlled. An analytical procedure for the retention/quantification of As(V) was then developed; the detection limit was 0.1 ng As(V)mL(-1) and the relative standard deviation 2.4-3.0%. The maximum effective retention capacity for As(V) was about 12.5mgAs(g biomass)(-1). The developed procedure was applied to the determination of total arsenic in coal fly ash, using a sample that had undergone oxidative pre-treatment. PMID:20006108

  4. Determination of arsenate in water by anion selective membrane electrode using polyurethane–silica gel fibrous anion exchanger composite

    International Nuclear Information System (INIS)

    Highlights: • PU–Si gel is new anion exchanger material synthesized and characterized. • This material used as anion exchange membrane is applied for electroanalytical studies. • The method for detection and determination of AsO43− in traces amounts discussed. • The results are also verified from arsenic analyzer. -- Abstract: Polyurethane (PU)–silica (Si gel) based fibrous anion exchanger composites were prepared by solid–gel polymerization of polyurethane in the presence of different amounts of silica gel. The formation of PU–Si gel fibrous anion exchanger composite was characterized by Fourier transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA-DTA), scanning electron microscopy (SEM) and elemental analysis. The membrane having a composition of 5:3 (PU:Si gel) shows best results for water content, porosity, thickness and swelling. Our studies show that the present ion selective membrane electrode is selective for arsenic, having detection limit (1 × 10−8 M to 1 × 10−1 M), response time (45 s) and working pH range (5–8). The selectivity coefficient values for interfering ions indicate good selectivity for arsenate (AsO43−) over interfering anions. The accuracy of the detection limit results was compared by PCA-Arsenomat

  5. Raman spectroscopic identification of arsenate minerals in situ at outcrops with handheld (532 nm, 785 nm) instruments.

    Science.gov (United States)

    Culka, Adam; Kindlová, Helena; Drahota, Petr; Jehlička, Jan

    2016-02-01

    Minerals are traditionally identified under field conditions by experienced mineralogists observing the basic physical properties of the samples. Under laboratory conditions, a plethora of techniques are commonly used for identification of the geological phases based on their structural and spectroscopic parameters. In this area, Raman spectrometry has become a useful tool to complement the more widely applied XRD. Today, however, there is an acute need for a technique for unambiguous in situ identification of minerals, within the geological as well as planetary/exobiology realms. With the potential for miniaturization, Raman spectroscopy can be viewed as a practical technique to achieve these goals. Here, for the first time, the successful application of handheld Raman spectrometers is demonstrated to detect and discriminate arsenic phases in the form of earthy aggregates. The Raman spectroscopic analyses of arsenate minerals were performed in situ using two handheld instruments, using 532 and 785 nm excitation. Bukovskýite, kaňkite, parascorodite, and scorodite were identified from Kaňk near Kutná Hora, CZE; kaňkite, scorodite, and zýkaite were identified at the Lehnschafter gallery in an old silver mine at Mikulov near Teplice, Bohemian Massif, CZE. PMID:26523686

  6. Photosynthesis is induced in rice plants that associate with arbuscular mycorrhizal fungi and are grown under arsenate and arsenite stress.

    Science.gov (United States)

    de Andrade, Sara Adrian Lopez; Domingues, Adilson Pereira; Mazzafera, Paulo

    2015-09-01

    The metalloid arsenic (As) increases in agricultural soils because of anthropogenic activities and may have phytotoxic effects depending on the available concentrations. Plant performance can be improved by arbuscular mycorrhiza (AM) association under challenging conditions, such as those caused by excessive soil As levels. In this study, the influence of AM on CO2 assimilation, chlorophyll a fluorescence, SPAD-chlorophyll contents and plant growth was investigated in rice plants exposed to arsenate (AsV) or arsenite (AsIII) and inoculated or not with Rhizophagus irregularis. Under AsV and AsIII exposure, AM rice plants had greater biomass accumulation and relative chlorophyll content, increased water-use efficiency, higher carbon assimilation rate and higher stomatal conductance and transpiration rates than non-AM rice plants did. Chlorophyll a fluorescence analysis revealed significant differences in the response of AM-associated and -non-associated plants to As. Mycorrhization increased the maximum and actual quantum yields of photosystem II and the electron transport rate, maintaining higher values even under As exposure. Apart from the negative effects of AsV and AsIII on the photosynthetic rates and PSII efficiency in rice leaves, taken together, these results indicate that AM is able to sustain higher rice photosynthesis efficiency even under elevated As concentrations, especially when As is present as AsV. PMID:25935603

  7. Exergy analysis of the Chartherm process for energy valorization and material recuperation of chromated copper arsenate (CCA) treated wood waste

    International Nuclear Information System (INIS)

    The Chartherm process (Thermya, Bordeaux, France) is a thermochemical conversion process to treat chromated copper arsenate (CCA) impregnated wood waste. The process aims at maximum energy valorization and material recuperation by combining the principles of low-temperature slow pyrolysis and distillation in a smart way. The main objective of the exergy analysis presented in this paper is to find the critical points in the Chartherm process where it is necessary to apply some measures in order to reduce exergy consumption and to make energy use more economic and efficient. It is found that the process efficiency can be increased with 2.3-4.2% by using the heat lost by the reactor, implementing a combined heat and power (CHP) system, or recuperating the waste heat from the exhaust gases to preheat the product gas. Furthermore, a comparison between the exergetic performances of a 'chartherisation' reactor and an idealized gasification reactor shows that both reactors destroy about the same amount of exergy (i.e. 3500 kW kgwood-1) during thermochemical conversion of CCA-treated wood. However, the Chartherm process possesses additional capabilities with respect to arsenic and tar treatment, as well as the extra benefit of recuperating materials.

  8. Leaching of chromated copper arsenate (CCA)-treated wood in a simulated monofill and its potential impacts to landfill leachate.

    Science.gov (United States)

    Jambeck, Jenna R; Townsend, Timothy; Solo-Gabriele, Helena

    2006-07-31

    The proper end-of-life management of chromated copper arsenate (CCA)-treated wood, which contains arsenic, copper, and chromium, is a concern to the solid waste management community. Landfills are often the final repository of this waste stream, and the impacts of CCA preservative metals on leachate quality are not well understood. Monofills are a type of landfill designed and operated to dispose a single waste type, such as ash, tires, mining waste, or wood. The feasibility of managing CCA-treated wood in monofills was examined using a simulated landfill (a leaching lysimeter) that contained a mix of new and weathered CCA-treated wood. The liquid to solid ratio (LS) reached in the experiment was 0.63:1. Arsenic, chromium, and copper leached from the lysimeter at average concentrations of 42 mg/L for arsenic, 9.4 mg/L for chromium, and 2.4 mg/L for copper. Complementary batch leaching studies using deionized water were performed on similar CCA-treated wood samples at LS of 5:1 and 10:1. When results from the lysimeter were compared to the batch test results, copper and chromium leachability appeared to be reduced in the lysimeter disposal environment. Of the three metals, arsenic leached to the greatest extent and was found to have the best correlation between the batch and the lysimeter experiments. PMID:16406290

  9. Leaching of chromated copper arsenate (CCA)-treated wood in a simulated monofill and its potential impacts to landfill leachate

    International Nuclear Information System (INIS)

    The proper end-of-life management of chromated copper arsenate (CCA)-treated wood, which contains arsenic, copper, and chromium, is a concern to the solid waste management community. Landfills are often the final repository of this waste stream, and the impacts of CCA preservative metals on leachate quality are not well understood. Monofills are a type of landfill designed and operated to dispose a single waste type, such as ash, tires, mining waste, or wood. The feasibility of managing CCA-treated wood in monofills was examined using a simulated landfill (a leaching lysimeter) that contained a mix of new and weathered CCA-treated wood. The liquid to solid ratio (LS) reached in the experiment was 0.63:1. Arsenic, chromium, and copper leached from the lysimeter at average concentrations of 42 mg/L for arsenic, 9.4 mg/L for chromium, and 2.4 mg/L for copper. Complementary batch leaching studies using deionized water were performed on similar CCA-treated wood samples at LS of 5:1 and 10:1. When results from the lysimeter were compared to the batch test results, copper and chromium leachability appeared to be reduced in the lysimeter disposal environment. Of the three metals, arsenic leached to the greatest extent and was found to have the best correlation between the batch and the lysimeter experiments

  10. Synthesis, crystal structure and charge distribution of Na7As11O31: An oxygen-deficient layered sodium arsenate

    International Nuclear Information System (INIS)

    A new sodium arsenate with layer structure has been synthesized and its crystal structure solved and refined by single-crystal X-ray diffraction. The crystal is trigonal, space group P3-bar m1, a=11.199(3)A, c=5.411(2)A, V=587.80(3)A3, Z=1; the refinement converged to R=0.0282 and wR=0.0751 for 590 reflections with (I)>2sigma(I). The structural model gives the formula Na7As11O32, which would be non-neutral; besides, the structural model is not validated by the charge distribution (CD) analysis, which gives an unsatisfactory agreement on the computed charges of the cations. The CD analysis suggest incomplete (5/6) occupation of the O5 site, which leads to the deficiency of an oxygen atom per unit cell and to formula Na7As11O31: this new structural model corresponds to a neutral compound, is validated by the CD analysis, and results in better displacement parameters for O5 than its non neutral counterpart. The (001) anionic layers are built up from corner and edge sharing of As1 and As2 distorted octahedra and As3 distorted tetrahedra, the sodium cations playing the role of interlayer cations. The effects of the oxygen deficiency on the crystal structure are discussed

  11. Unsuspected myasthenia gravis presenting as respiratory failure.

    OpenAIRE

    Mier, A; Laroche, C; Green, M

    1990-01-01

    A patient developed respiratory failure after surgical removal of a recurrent thymoma, which necessitated removal of part of the diaphragm. The respiratory failure was due to previously undiagnosed myasthenia gravis, which had selectively affected the respiratory muscles.

  12. Activity of the Respiratory Chain Enzymes of Blood Leucocytes’ Mitochondria Under the Conditions of Toxic Hepatitis Induced Against the Background Alimentary Deprivation of Protein

    Directory of Open Access Journals (Sweden)

    O.N. Voloshchuk

    2015-12-01

    Full Text Available Full functioning of the leucocytes’ energy supply system is one of the essential factors for the immune surveillance system effective work. The pivotal enzymes of the leucocytes’ energy biotransformation system are NADH-ubiquitin reductase, a marker of the Complex I of respiratory chain activity, and succinate dehydrogenase, key enzyme of the Complex II of respiratory chain. The aim of research – to study the NADH-ubiquitin reductase and succinate dehydrogenase activity of the blood leucocytes’ mitochondria under the conditions of toxic hepatitis induced against the background alimentary deprivation of protein. It is shown, that under the conditions of acetaminophen-induced hepatitis a reduction of the NADH-ubiquitin reductase enzymatic activity is observed on the background activation of the succinate-dependent way of the mitochondrial oxidation. Conclusion was made that alimentary deprivation or protein is a factor, aggravating the misbalance of the energy biotransformation system in the leucocytes of rats with toxic hepatitis. Established activity changes of the leucocytes’ mitochondria respiratory chain key enzymes may be considered as one of the mechanisms, directed on the maintenance of leucocytes energy supply on a level, sufficient for their functioning. Research results may be used for the biochemical rationale of the therapeutic approaches to the elimination and correction of the leucocytes’ energy metabolism disturbances consequences under the conditions of acetaminophen-induced hepatitis, aggravated by the alimentary protein deprivation.

  13. Multiplex detection of respiratory pathogens

    Energy Technology Data Exchange (ETDEWEB)

    McBride, Mary (Brentwood, CA); Slezak, Thomas (Livermore, CA); Birch, James M. (Albany, CA)

    2012-07-31

    Described are kits and methods useful for detection of respiratory pathogens (influenza A (including subtyping capability for H1, H3, H5 and H7 subtypes) influenza B, parainfluenza (type 2), respiratory syncytial virus, and adenovirus) in a sample. Genomic sequence information from the respiratory pathogens was analyzed to identify signature sequences, e.g., polynucleotide sequences useful for confirming the presence or absence of a pathogen in a sample. Primer and probe sets were designed and optimized for use in a PCR based, multiplexed Luminex assay to successfully identify the presence or absence of pathogens in a sample.

  14. Acute Respiratory Distress Syndrome.

    Science.gov (United States)

    Yadam, Suman; Bihler, Eric; Balaan, Marvin

    2016-01-01

    Acute respiratory distress syndrome (ARDS) is a serious inflammatory disorder with high mortality. Its main pathologic mechanism seems to result from increased alveolar permeability. Its definition has also changed since first being described according to the Berlin definition, which now classifies ARDS on a severity scale based on PaO2 (partial pressure of oxygen, arterial)/FIO2 (fraction of inspired oxygen) ratio. The cornerstone of therapy was found to be a low tidal volume strategy featuring volumes of 6 to 8 mL per kg of ideal body weight that has been shown to have decreased mortality as proven by the ARDSnet trials. There are other areas of treatment right now that include extracorporeal membrane oxygenation, as well for severe refractory hypoxemia. Other methods that include prone positioning for ventilation have also shown improvements in oxygenation. Positive end-expiratory pressure with lung recruitment maneuvers has also been found to be helpful. Other therapies that include vasodilators and neuromuscular agents are still being explored and need further studies to define their role in ARDS. PMID:26919679

  15. Achromobacter respiratory infections.

    Science.gov (United States)

    Swenson, Colin E; Sadikot, Ruxana T

    2015-02-01

    Achromobacteria are ubiquitous environmental organisms that may also become opportunistic pathogens in certain conditions, such as cystic fibrosis, hematologic and solid organ malignancies, renal failure, and certain immune deficiencies. Some members of this genus, such as xylosoxidans, cause primarily nosocomially acquired infections affecting multiple organ systems, including the respiratory tract, urinary tract, and, less commonly, the cardiovascular and central nervous systems. Despite an increasing number of published case reports and literature reviews suggesting a global increase in achromobacterial disease, most clinicians remain uncertain of the organism's significance when clinically isolated. Moreover, effective treatment can be challenging due to the organism's inherent and acquired multidrug resistance patterns. We reviewed all published cases to date of non-cystic fibrosis achromobacterial lung infections to better understand the organism's pathogenic potential and drug susceptibilities. We found that the majority of these cases were community acquired, typically presenting as pneumonias (88%), and were most frequent in individuals with hematologic and solid organ malignancies. Our findings also suggest that achromobacterial lung infections are difficult to treat, but respond well to extended-spectrum penicillins and cephalosporins, such as ticarcillin, piperacillin, and cefoperazone. PMID:25706494

  16. [Vaccinations in respiratory medicine].

    Science.gov (United States)

    Lode, H M; Stahlmann, R

    2015-09-01

    Vaccinations are the most successful and cost-effective measures for prevention of infections. Important pathogens of respiratory tract infections (e.g. influenza viruses and pneumococci) can be effectively treated by vaccinations. The seasonal trivalent and recently now quadrivalent influenza vaccines include antigens from influenza A and B type viruses, which have to be modified annually oriented to the circulating strains. The effective protection by influenza vaccination varies considerably (too short protection time, mismatch); therefore, administration late in the year is the best approach (November/December). Two pneumococcal vaccines are recommended for adults: the over 30-year-old 23-valent polysaccharide vaccine (PPV23) and the 4-year-old 13-valent conjugate vaccine (PCV13). The immunological and clinical efficacy of PPV23 is controversially discussed; however, a moderate reduction of invasive pneumococcal infections is widely accepted. The PCV13 stimulates a T-cell response and has currently demonstrated its clinical efficacy in an impressive study (CAPiTA). The problem of PCV13 is the relatively limited coverage of only 47% of the currently circulating invasive pneumococcal serotypes. PMID:26330051

  17. Rapid Identification of Aldose Reductase Inhibitory Compounds from Perilla frutescens

    OpenAIRE

    Soon Sung Lim; Ji Hun Paek; Kuk Hyun Shin; Young-Hee Kang; Jae-Yong Lee

    2013-01-01

    The ethyl acetate (EtOAc) soluble fraction of methanol extracts of Perilla frutescens (P. frutescens) inhibits aldose reductase (AR), the key enzyme in the polyol pathway. Our investigation of inhibitory compounds from the EtOAc soluble fraction of P. frutescens was followed by identification of the inhibitory compounds by a combination of HPLC microfractionation and a 96-well enzyme assay. This allowed the biological activities to be efficiently matched with selected HPLC peaks. Structural a...

  18. Determination of plasma gluthatione reductase enzyme activity in osteoporotic women

    OpenAIRE

    Sadeghi N; Oveisi M.R.; Jannat B.; Hajimahmoodi M; Jamshidi A.R; Sajadian Z.

    2008-01-01

    Background: Osteoporosis is a disease of high prevalence with increased bone loss. Free radicals have been proved to be involved in bone resorption. Glutathione reductase (GR) plays an essential role in cell defense against reactive oxygen metabolites by sustaining the reduced status of an important antioxidant, glutathione. In the present study GR activity of plasma as an antioxidant enzyme in relation to Bone Mineral Density (BMD) was investigated.Material and Method: GR activity was measur...

  19. Glutathione reductase: solvent equilibrium and kinetic isotope effects

    International Nuclear Information System (INIS)

    Glutathione reductase catalyzes the NADPH-dependent reduction of oxidized glutathione (GSSG). The kinetic mechanism is ping-pong, and we have investigated the rate-limiting nature of proton-transfer steps in the reactions catalyzed by the spinach, yeast, and human erythrocyte glutathione reductases using a combination of alternate substrate and solvent kinetic isotope effects. With NADPH or GSSG as the variable substrate, at a fixed, saturating concentration of the other substrate, solvent kinetic isotope effects were observed on V but not V/K. Plots of Vm vs mole fraction of D2O (proton inventories) were linear in both cases for the yeast, spinach, and human erythrocyte enzymes. When solvent kinetic isotope effect studies were performed with DTNB instead of GSSG as an alternate substrate, a solvent kinetic isotope effect of 1.0 was observed. Solvent kinetic isotope effect measurements were also performed on the asymmetric disulfides GSSNB and GSSNP by using human erythrocyte glutathione reductase. The Km values for GSSNB and GSSNP were 70 microM and 13 microM, respectively, and V values were 62 and 57% of the one calculated for GSSG, respectively. Both of these substrates yield solvent kinetic isotope effects greater than 1.0 on both V and V/K and linear proton inventories, indicating that a single proton-transfer step is still rate limiting. These data are discussed in relationship to the chemical mechanism of GSSG reduction and the identity of the proton-transfer step whose rate is sensitive to solvent isotopic composition. Finally, the solvent equilibrium isotope effect measured with yeast glutathione reductase is 4.98, which allows us to calculate a fractionation factor for the thiol moiety of GSH of 0.456

  20. Aldo-keto reductase (AKR) superfamily: Genomics and annotation

    OpenAIRE

    Mindnich Rebekka D; Penning Trevor M

    2009-01-01

    Abstract Aldo-keto reductases (AKRs) are phase I metabolising enzymes that catalyse the reduced nicotinamide adenine dinucleotide (phosphate) (NAD(P)H)-dependent reduction of carbonyl groups to yield primary and secondary alcohols on a wide range of substrates, including aliphatic and aromatic aldehydes and ketones, ketoprostaglan-dins, ketosteroids and xenobiotics. In so doing they functionalise the carbonyl group for conjugation (phase II enzyme reactions). Although functionally diverse, AK...

  1. Phosphoglycerate kinase acts in tumour angiogenesis as a disulphide reductase

    Science.gov (United States)

    Lay, Angelina J.; Jiang, Xing-Mai; Kisker, Oliver; Flynn, Evelyn; Underwood, Anne; Condron, Rosemary; Hogg, Philip J.

    2000-12-01

    Disulphide bonds in secreted proteins are considered to be inert because of the oxidizing nature of the extracellular milieu. An exception to this rule is a reductase secreted by tumour cells that reduces disulphide bonds in the serine proteinase plasmin. Reduction of plasmin initiates proteolytic cleavage in the kringle 5 domain and release of the tumour blood vessel inhibitor angiostatin. New blood vessel formation or angiogenesis is critical for tumour expansion and metastasis. Here we show that the plasmin reductase isolated from conditioned medium of fibrosarcoma cells is the glycolytic enzyme phosphoglycerate kinase. Recombinant phosphoglycerate kinase had the same specific activity as the fibrosarcoma-derived protein. Plasma of mice bearing fibrosarcoma tumours contained several-fold more phosphoglycerate kinase, as compared with mice without tumours. Administration of phosphoglycerate kinase to tumour-bearing mice caused an increase in plasma levels of angiostatin, and a decrease in tumour vascularity and rate of tumour growth. Our findings indicate that phosphoglycerate kinase not only functions in glycolysis but is secreted by tumour cells and participates in the angiogenic process as a disulphide reductase.

  2. Cloning and sequence of the human adrenodoxin reductase gene

    International Nuclear Information System (INIS)

    Adrenodoxin reductase is a flavoprotein mediating electron transport to all mitochondrial forms of cytochrome P450. The authors cloned the human adrenodoxin reductase gene and characterized it by restriction endonuclease mapping and DNA sequencing. The entire gene is approximately 12 kilobases long and consists of 12 exons. The first exon encodes the first 26 of the 32 amino acids of the signal peptide, and the second exon encodes the remainder of signal peptide and the apparent FAD binding site. The remaining 10 exons are clustered in a region of only 4.3 kilobases, separated from the first two exons by a large intron of about 5.6 kilobases. Two forms of human adrenodoxin reductase mRNA, differing by the presence or absence of 18 bases in the middle of the sequence, arise from alternate splicing at the 5' end of exon 7. This alternately spliced region is directly adjacent to the NADPH binding site, which is entirely contained in exon 6. The immediate 5' flanking region lacks TATA and CAAT boxes; however, this region is rich in G+C and contains six copies of the sequence GGGCGGG, resembling promoter sequences of housekeeping genes. RNase protection experiments show that transcription is initiated from multiple sites in the 5' flanking region, located about 21-91 base pairs upstream from the AUG translational initiation codon

  3. How Is Respiratory Failure Treated?

    Science.gov (United States)

    ... Once your doctor figures out what's causing your respiratory failure, he or she will plan how to treat that disease or condition. Treatments may include medicines, procedures, and other therapies. Rate This Content: NEXT >> Updated: December 19, 2011 Twitter ...

  4. Research outputs in respiratory medicine

    OpenAIRE

    Rippon, I; Lewison, G; Partridge, M

    2005-01-01

    Background: There is currently little information regarding how much the distribution of research activity in respiratory medicine reflects the interests of its clinicians and scientists, the disease burden in any country, or the availability of funding.

  5. Middle East Respiratory Syndrome (MERS)

    Science.gov (United States)

    Middle East Respiratory Syndrome Coronavirus; MERS-CoV; Novel coronavirus; nCoV ... Centers for Disease Control and Prevention. Middle East ... 2, 2015. www.cdc.gov/coronavirus/mers/faq.html . Accessed April ...

  6. Behavioural and Physiological Responses of Gammarus pulex Exposed to Cadmium and Arsenate at Three Temperatures: Individual and Combined Effects

    Science.gov (United States)

    Vellinger, Céline; Felten, Vincent; Sornom, Pascal; Rousselle, Philippe; Beisel, Jean-Nicolas; Usseglio-Polatera, Philippe

    2012-01-01

    This study aimed at investigating both the individual and combined effects of cadmium (Cd) and arsenate (AsV) on the physiology and behaviour of the Crustacean Gammarus pulex at three temperatures (5, 10 and15°C). G. pulex was exposed during 96 h to (i) two [Cd] alone, (ii) two [AsV] alone, and (iii) four combinations of [Cd] and [AsV] to obtain a complete factorial plane. After exposure, survival, [AsV] or [Cd] in body tissues, behavioural (ventilatory and locomotor activities) and physiological responses (iono-regulation of [Na+] and [Cl−] in haemolymph) were examined. The interactive effects (antagonistic, additive or synergistic) of binary mixtures were evaluated for each tested temperature using a predictive model for the theoretically expected interactive effect of chemicals. In single metal exposure, both the internal metal concentration in body tissues and the mortality rate increased along metallic gradient concentration. Cd alone significantly impaired both [Na+] and [Cl−] while AsV alone had a weak impact only on [Cl−]. The behavioural responses of G. pulex declined with increasing metal concentration suggesting a reallocation of energy from behavioural responses to maintenance functions. The interaction between AsV and Cd was considered as ‘additive’ for all the tested binary mixtures and temperatures (except for the lowest combination at 10°C considered as “antagonistic”). In binary mixtures, the decrease in both ventilatory and locomotor activities and the decline in haemolymphatic [Cl−] were amplified when respectively compared to those observed with the same concentrations of AsV or Cd alone. However, the presence of AsV decreased the haemolymphatic [Na+] loss when G. pulex was exposed to the lowest Cd concentration. Finally, the observed physiological and behavioural effects (except ventilation) in G. pulex exposed to AsV and/or Cd were exacerbated under the highest temperature. The discussion encompasses both the toxicity

  7. Adsorption and desorption of arsenate on sandy sediments from contaminated and uncontaminated saturated zones: Kinetic and equilibrium modeling.

    Science.gov (United States)

    Hafeznezami, Saeedreza; Zimmer-Faust, Amity G; Dunne, Aislinn; Tran, Tiffany; Yang, Chao; Lam, Jacquelyn R; Reynolds, Matthew D; Davis, James A; Jay, Jennifer A

    2016-08-01

    Application of empirical models to adsorption of contaminants on natural heterogeneous sorbents is often challenging due to the uncertainty associated with fitting experimental data and determining adjustable parameters. Sediment samples from contaminated and uncontaminated portions of a study site in Maine, USA were collected and investigated for adsorption of arsenate [As(V)]. Two kinetic models were used to describe the results of single solute batch adsorption experiments. Piecewise linear regression of data linearized to fit pseudo-first order kinetic model resulted in two distinct rates and a cutoff time point of 14-19 h delineating the biphasic behavior of solute adsorption. During the initial rapid adsorption stage, an average of 60-80% of the total adsorption took place. Pseudo-second order kinetic models provided the best fit to the experimental data (R(2) > 0.99) and were capable of describing the adsorption over the entire range of experiments. Both Langmuir and Freundlich isotherms provided reasonable fits to the adsorption data at equilibrium. Langmuir-derived maximum adsorption capacity (St) of the studied sediments ranged between 29 and 97 mg/kg increasing from contaminated to uncontaminated sites. Solid phase As content of the sediments ranged from 3.8 to 10 mg/kg and the As/Fe ratios were highest in the amorphous phase. High-pH desorption experiments resulted in a greater percentage of solid phase As released into solution from experimentally-loaded sediments than from the unaltered samples suggesting that As(V) adsorption takes place on different reversible and irreversible surface sites. PMID:27218893

  8. Investigating the Proton Donor in the NO Reductase from Paracoccus denitrificans

    Science.gov (United States)

    ter Beek, Josy; Krause, Nils; Ädelroth, Pia

    2016-01-01

    Variant nomenclature: the variants were made in the NorB subunit if not indicated by the superscript c, which are variants in the NorC subunit (e.g. E122A = exchange of Glu-122 in NorB for an Ala, E71cD; exchange of Glu-71 in NorC for an Asp). Bacterial NO reductases (NORs) are integral membrane proteins from the heme-copper oxidase superfamily. Most heme-copper oxidases are proton-pumping enzymes that reduce O2 as the last step in the respiratory chain. With electrons from cytochrome c, NO reductase (cNOR) from Paracoccus (P.) denitrificans reduces NO to N2O via the following reaction: 2NO+2e-+2H+→N2O+H2O. Although this reaction is as exergonic as O2-reduction, cNOR does not contribute to the electrochemical gradient over the membrane. This means that cNOR does not pump protons and that the protons needed for the reaction are taken from the periplasmic side of the membrane (since the electrons are donated from this side). We previously showed that the P. denitrificans cNOR uses a single defined proton pathway with residues Glu-58 and Lys-54 from the NorC subunit at the entrance. Here we further strengthened the evidence in support of this pathway. Our further aim was to define the continuation of the pathway and the immediate proton donor for the active site. To this end, we investigated the region around the calcium-binding site and both propionates of heme b3 by site directed mutagenesis. Changing single amino acids in these areas often had severe effects on cNOR function, with many variants having a perturbed active site, making detailed analysis of proton transfer properties difficult. Our data does however indicate that the calcium ligation sphere and the region around the heme b3 propionates are important for proton transfer and presumably contain the proton donor. The possible evolutionary link between the area for the immediate donor in cNOR and the proton loading site (PLS) for pumped protons in oxygen-reducing heme-copper oxidases is discussed. PMID

  9. Macrophage Heterogeneity in Respiratory Diseases

    OpenAIRE

    Boorsma, Carian E.; Christina Draijer; Barbro N. Melgert

    2013-01-01

    Macrophages are among the most abundant cells in the respiratory tract, and they can have strikingly different phenotypes within this environment. Our knowledge of the different phenotypes and their functions in the lung is sketchy at best, but they appear to be linked to the protection of gas exchange against microbial threats and excessive tissue responses. Phenotypical changes of macrophages within the lung are found in many respiratory diseases including asthma, chronic obstructive pulmon...

  10. The acute respiratory distress syndrome

    OpenAIRE

    Modrykamien, Ariel M.; Gupta, Pooja

    2015-01-01

    The acute respiratory distress syndrome (ARDS) is a major cause of acute respiratory failure. Its development leads to high rates of mortality, as well as short- and long-term complications, such as physical and cognitive impairment. Therefore, early recognition of this syndrome and application of demonstrated therapeutic interventions are essential to change the natural course of this devastating entity. In this review article, we describe updated concepts in ARDS. Specifically, we discuss t...

  11. Natural arsenic attenuation via metal arsenate precipitation in soils contaminated with metallurgical wastes: III. Adsorption versus precipitation in clean As(V)/goethite/Pb(II)/carbonate systems

    International Nuclear Information System (INIS)

    Soil contamination with As and potentially harmful metals is a widespread problem around the world especially from mining and metallurgical wastes, which release substantial amounts of these elements to the environment in potentially mobile species. Recently, it has been found that in various Mexican soils contaminated with these types of wastes, arsenate is not in the form of sorbed species on Fe oxides present in the soils, as generally reported in the literature, but in the form of very insoluble compounds such as Pb, Cu and Ca arsenates. Here a thermodynamic model is applied and validated with the results from wet chemical experiments to determine the fundamental geochemical conditions governing the mobility of As in the presence of Pb. For this purpose, a relatively simple but fundamental system of goethite (α-FeOOH)/As(V)/Pb(II)/carbonate was defined as a function of the As(V)/Fe(III) ratio, in a pH range of 5–10. The speciation model included the simultaneous inclusion of triple layer surface complexation and arsenate precipitation equilibria. The model predicts that from very low total As(V)/Fe(III) molar ratios (0.012 at pH 7) the precipitation mechanism significantly influences the attenuation of As(V), and rapidly becomes the dominant process over the adsorption mechanism. Model results identify the quantitative conditions of predominance for each mechanism and describe the transition conditions in which relatively large fractions of adsorbed, precipitated and dissolved As(V) species prevail. Experimental measurements at selected As(V)/Fe(III) ratios and pH confirmed the predictions and validated the coupled thermodynamic model utilized.

  12. Effects of co-administration of dietary sodium arsenate and 2,3-dimercaptopropane-1-sulfonic acid (DMPS) on the rat bladder epithelium

    International Nuclear Information System (INIS)

    Inorganic arsenic is a known human carcinogen, inducing tumors of the skin, urinary bladder and lung. It is metabolized to organic methylated arsenicals. 2,3-Dimercaptopropane-1-sulfonic acid (DMPS), a chelating agent, is capable of reducing pentavalent arsenicals to the trivalent state and binding to the trivalent species, and it has been used in the treatment of heavy metal poisoning in humans. Therefore, we investigated the ability of DMPS to inhibit the cytotoxicity and regenerative urothelial cell proliferation induced by arsenate administration in vivo. Female rats were treated for 4 weeks with 100 ppm AsV. DMPS (2800 ppm) co-administered in the diet significantly reduced the AsV-induced cytotoxicity of superficial cells detected by scanning electron microscopy (SEM), and the incidence of simple hyperplasia observed by light microscopy and the bromodeoxyuridine (BrdU) labeling index. It also reduced the total concentration of arsenicals in the urine and the methylation of arsenic. There were no differences in oxidative stress as assessed by immunohistochemical staining for 8-hydroxy-2′-deoxyguanosine (8OHdG) of the bladder urothelium. No differences were detected in urine sediments between groups. These data suggest that DMPS has the ability to inhibit both arsenate-induced acute toxicity and regenerative proliferation of the rat bladder epithelium, most likely by decreasing exposure of the urothelium to trivalent arsenicals excreted in the urine. These data provide additional evidence that the effects of arsenate exposure in vivo do not appear to be related to oxidative effects on dG in DNA.

  13. Climate Change and Respiratory Infections.

    Science.gov (United States)

    Mirsaeidi, Mehdi; Motahari, Hooman; Taghizadeh Khamesi, Mojdeh; Sharifi, Arash; Campos, Michael; Schraufnagel, Dean E

    2016-08-01

    The rate of global warming has accelerated over the past 50 years. Increasing surface temperature is melting glaciers and raising the sea level. More flooding, droughts, hurricanes, and heat waves are being reported. Accelerated changes in climate are already affecting human health, in part by altering the epidemiology of climate-sensitive pathogens. In particular, climate change may alter the incidence and severity of respiratory infections by affecting vectors and host immune responses. Certain respiratory infections, such as avian influenza and coccidioidomycosis, are occurring in locations previously unaffected, apparently because of global warming. Young children and older adults appear to be particularly vulnerable to rapid fluctuations in ambient temperature. For example, an increase in the incidence in childhood pneumonia in Australia has been associated with sharp temperature drops from one day to the next. Extreme weather events, such as heat waves, floods, major storms, drought, and wildfires, are also believed to change the incidence of respiratory infections. An outbreak of aspergillosis among Japanese survivors of the 2011 tsunami is one such well-documented example. Changes in temperature, precipitation, relative humidity, and air pollution influence viral activity and transmission. For example, in early 2000, an outbreak of Hantavirus respiratory disease was linked to a local increase in the rodent population, which in turn was attributed to a two- to threefold increase in rainfall before the outbreak. Climate-sensitive respiratory pathogens present challenges to respiratory health that may be far greater in the foreseeable future. PMID:27300144

  14. Functional interplay between glutathione and hydrogen sulfide in regulation of thiol cascade during arsenate tolerance of common bean (Phaseolus vulgaris L.) genotypes

    OpenAIRE

    Talukdar, Dibyendu

    2015-01-01

    Changes in expressions of up- and downstream thiol cascade were studied in leaves of Phaseolus vulgaris L. cv. VL-63 and its mutant, pvsod1 (deficient in superoxide dismutase activity) under 50 μM sodium arsenate (As), As + l-buthionine-sulfoximine (BSO) and As + BSO + Sodium hydrosulfide (NaHS)-treatments for 10 days. Main objective was to investigate the functional relationship between hydrogen sulfide (H2S) and glutathione (GSH) in regulation of sulfate transporters and cysteine metabolism...

  15. Urgencias respiratorias Respiratory emergencies

    Directory of Open Access Journals (Sweden)

    E. Martínez

    2004-01-01

    Full Text Available Las urgencias respiratorias en un paciente con cáncer pueden tener su origen en patologías de la vía aérea, del parénquima pulmonar o de los grandes vasos. La causa puede ser el propio tumor o complicaciones concomitantes. La obstrucción de la vía aérea debería ser inicialmente evaluada con procedimientos endoscópicos. En situaciones severas, la cirugía raramente es posible. El emplazamiento endobronquial de stents e isótopos radiactivos (braquiterapia, la ablación tumoral por láser o la terapia fotodinámica, pueden aliviar de forma rápida los síntomas y reestablecer el flujo aéreo. El manejo de la hemoptisis depende de la causa que la provoque y de la cuantía de la misma. La broncoscopia sigue siendo el procedimiento de primera línea en la mayor parte de los casos; aporta información diagnóstica y puede interrumpir el sangrado mediante lavados con suero helado, taponamiento endobronquial o inyecciones tópicas de adrenalina o trombina. La radioterapia externa sigue siendo un procedimiento extraordinariamente útil para tratar la hemoptisis de causa tumoral y en situaciones bien seleccionadas la terapia endobronquial con láser o braquiterapia y la embolización arterial bronquial pueden proporcionar un gran rendimiento paliativo. Las urgencias respiratorias por enfermedad del parénquima pulmonar en un paciente oncológico, pueden tener causa tumoral, iatrogénica o infecciosa. El reconocimiento precoz de cada una de ellas determina la administración del tratamiento específico y las posibilidades de éxito.Respiratory emergencies in a patient with cancer can have their origin in pathologies of the airway, of the pulmonary parenchyma or the large vessels. The cause can be the tumour itself or concomitant complications. Obstruction of the airway should be initially evaluated with endoscopic procedures. Surgery is rarely possible in serious situations. The endobronchial placement of stents or radioactive isotopes

  16. Rigid spine syndrome with respiratory failure.

    OpenAIRE

    Morita, H.; Kondo, K.; Hoshino, K; Maruyama, K; Yanagisawa, N

    1990-01-01

    The pathogenesis and therapy of respiratory failure in the rigid spine syndrome are discussed in two cases who improved with respiratory assistance. In both cases, the partial pressures of oxygen and carbon dioxide were reversed in arterial blood gas analysis and %VC was less than 30%. Remission from respiratory failure has been obtained by the use of a ventilator during the night. The cause of the respiratory failure in both cases was severe restrictive respiratory dysfunction due to extreme...

  17. Immunological comparison of the NADH:nitrate reductase from different cucumber tissues

    OpenAIRE

    Jolanta Marciniak; Grażyna Kłobus; Józef Buczek; Tadeusz Stefaniak; Jarosław Mazur

    2014-01-01

    Soluble nitrate reductase from cucumber roots (Cucumis sativus L.) was isolated and purified with blue-Sepharose 4B. Specific antibodies against the NR protein were raised by immunization of a goat. Using polyclonal antibodies anti-NR properties of the nitrate reductase from various cucumber tissues were examined. Experiments showed difference in immuno-logical properties of nitrate reductase (NR) from cotyledon roots and leaves.

  18. Immunological comparison of the NADH:nitrate reductase from different cucumber tissues

    Directory of Open Access Journals (Sweden)

    Jolanta Marciniak

    2014-02-01

    Full Text Available Soluble nitrate reductase from cucumber roots (Cucumis sativus L. was isolated and purified with blue-Sepharose 4B. Specific antibodies against the NR protein were raised by immunization of a goat. Using polyclonal antibodies anti-NR properties of the nitrate reductase from various cucumber tissues were examined. Experiments showed difference in immuno-logical properties of nitrate reductase (NR from cotyledon roots and leaves.

  19. Histochemical Localization of Glutathione Dependent NBT-Reductase in Mouse Skin

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective Localization of the glutathione dependent Nitroblue tetrazolium (NBT) reductase in fresh frozen sections of mouse skin and possible dependence of NBT reductase on tissue thiol levels has been investigated. Methods The fresh frozen tissue sections (8m thickness) were prepared and incubated in medium containing NBT, reduced glutathione (GSH) and phosphate buffer. The staining for GSH was performed with mercury orange. Results  The activity of the NBT-reductase in mouse skin has been found to be localized in the areas rich in glutathione and actively proliferating area of the skin. Conclusion The activity of the NBT-reductase seems to be dependent on the glutathione contents.

  20. Altered Respiratory Physiology in Obesity

    Directory of Open Access Journals (Sweden)

    Krishnan Parameswaran

    2006-01-01

    Full Text Available The major respiratory complications of obesity include a heightened demand for ventilation, elevated work of breathing, respiratory muscle inefficiency and diminished respiratory compliance. The decreased functional residual capacity and expiratory reserve volume, with a high closing volume to functional residual capacity ratio of obesity, are associated with the closure of peripheral lung units, ventilation to perfusion ratio abnormalities and hypoxemia, especially in the supine position. Conventional respiratory function tests are only mildly affected by obesity except in extreme cases. The major circulatory complications are increased total and pulmonary blood volume, high cardiac output and elevated left ventricular end-diastolic pressure. Patients with obesity commonly develop hypoventilation and sleep apnea syndromes with attenuated hypoxic and hypercapnic ventilatory responsiveness. The final result is hypoxemia, pulmonary hypertension and progressively worsening disability. Obese patients have increased dyspnea and decreased exercise capacity, which are vital to quality of life. Decreased muscle, increased joint pain and skin friction are important determinants of decreased exercise capacity, in addition to the cardiopulmonary effects of obesity. The effects of obesity on mortality in heart failure and chronic obstructive pulmonary disease have not been definitively resolved. Whether obesity contributes to asthma and airway hyper-responsiveness is uncertain. Weight reduction and physical activity are effective means of reversing the respiratory complications of obesity.

  1. Pyrobaculum yellowstonensis Strain WP30 Respires on Elemental Sulfur and/or Arsenate in Circumneutral Sulfidic Geothermal Sediments of Yellowstone National Park.

    Science.gov (United States)

    Jay, Z J; Beam, J P; Dohnalkova, A; Lohmayer, R; Bodle, B; Planer-Friedrich, B; Romine, M; Inskeep, W P

    2015-09-01

    Thermoproteales (phylum Crenarchaeota) populations are abundant in high-temperature (>70°C) environments of Yellowstone National Park (YNP) and are important in mediating the biogeochemical cycles of sulfur, arsenic, and carbon. The objectives of this study were to determine the specific physiological attributes of the isolate Pyrobaculum yellowstonensis strain WP30, which was obtained from an elemental sulfur sediment (Joseph's Coat Hot Spring [JCHS], 80°C, pH 6.1, 135 μM As) and relate this organism to geochemical processes occurring in situ. Strain WP30 is a chemoorganoheterotroph and requires elemental sulfur and/or arsenate as an electron acceptor. Growth in the presence of elemental sulfur and arsenate resulted in the formation of thioarsenates and polysulfides. The complete genome of this organism was sequenced (1.99 Mb, 58% G+C content), revealing numerous metabolic pathways for the degradation of carbohydrates, amino acids, and lipids. Multiple dimethyl sulfoxide-molybdopterin (DMSO-MPT) oxidoreductase genes, which are implicated in the reduction of sulfur and arsenic, were identified. Pathways for the de novo synthesis of nearly all required cofactors and metabolites were identified. The comparative genomics of P. yellowstonensis and the assembled metagenome sequence from JCHS showed that this organism is highly related (∼95% average nucleotide sequence identity) to in situ populations. The physiological attributes and metabolic capabilities of P. yellowstonensis provide an important foundation for developing an understanding of the distribution and function of these populations in YNP. PMID:26092468

  2. Synthesis and evaluation of chromate and arsenate anions extraction ability of a N-methylglucamine derivative of calix[4]arene immobilized onto magnetic nanoparticles

    International Nuclear Information System (INIS)

    In this study, 5,17-bis-[(N-methylglucamine)methyl]-25,26,27,28-tetrahydroxy-calix[4]arene (3) was synthesized by the treatment of calix[4]arene with a secondary amine N-methylglucamine and formaldehyde. The calixarene derivative (3) was characterized by a combination of FTIR, 1H NMR and elemental analyses. Followingly, using the macrocyclic building block, the compound 3 was immobilized by [3-(2,3-epoxypropoxy)propyl]trimethoxysilane-modified Fe3O4 magnetite nanoparticles (EPPTMS-MN). The prepared calix[4]arene immobilized material was characterized by a combination of Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM) and thermogravimetric analyses (TGA). Moreover, the studies regarding the removal of arsenate and dichromate ions from the aqueous solutions were also carried out by using the compound in solid-liquid extraction experiments. It was found that the calix[4]arene-based magnetic material has high extraction ability towards dichromate and arsenate anions in 66% (at pH 1.5) and in 86% (at pH 3.5), respectively.

  3. New inorganic (an)ion exchangers with a higher affinity for arsenate and a competitive removal capacity towards fluoride, bromate, bromide, selenate, selenite, arsenite and borate

    KAUST Repository

    Chubar, Natalia

    2011-12-01

    Highly selective materials and effective technologies are needed to meet the increasingly stronger drinking water standards for targeted ionic species. Inorganic ion exchangers based on individual and mixed-metal hydrous oxides (or mixed adsorbents that contain inorganic ion exchangers in their composition) are adsorptive materials that are capable of lowering the concentrations of anionic contaminants, such as H 2AsO 4 -, H 3AsO 3, F -, Br -, BrO 3 -, HSeO 4 -, HSeO 3 - and H 3BO 3, to 10 μg/L or less. To achieve a higher selectivity towards arsenate, a new ion exchanger based on Mg-Al hydrous oxides was developed by a novel, cost-effective and environmentally friendly synthesis method via a non-traditional (alkoxide-free) sol-gel approach. The exceptional adsorptive capacity of the Mg-Al hydrous oxides towards H 2AsO 4 - (up to 200 mg[As]/gdw) is due to the high affinity of this sorbent towards arsenate (steep equilibrium isotherms) and its fast adsorption kinetics. Because of the mesoporous (as determined by N 2 adsorption and SEM) and layered (as determined by XRD and FTIR) structure of the ion-exchange material as well as the abundance of anion exchange sites (as determined by XPS and potentiometric titration) on its surface the material demonstrated very competitive (or very high) removal capacity towards other targeted anions, including fluoride, bromide, bromate, selenate, selenite, and borate. © 2011 IWA Publishing.

  4. Synthesis, characterization and study of arsenate adsorption from aqueous solution by α- and δ-phase manganese dioxide nanoadsorbents

    International Nuclear Information System (INIS)

    Single-phase α-MnO2 nanorods and δ-MnO2 nano-fiber clumps were synthesized using manganese pentahydrate in an aqueous solution. These nanomaterials were characterized using the Transmission Electron Microscope (TEM), Field Emission Scanning Electron Microscope (FE-SEM), Powder X-ray diffraction (XRD) and the Brunauer-Elmet-Teller nitrogen adsorption technique (BET-N2 adsorption). The structural analysis shows that α-MnO2 (2x2 tunnel structure) has the form of needle-shaped nanorods and δ-MnO2 (2D-layered structure) consists of fine needle-like fibers arranged in ball-like aggregates. Batch adsorption experiments were carried out to determine the effect of pH on adsorption kinetics and adsorption capacity for the removal of As(V) from aqueous solution onto these two types of nanoadsorbents. The adsorption capacity of As(V) was found to be highly pH dependent. The adsorption of As(V) onto α-MnO2 reached equilibrium more rapidly with higher adsorption capacity compared to δ-MnO2. -- Graphical abstract: α-MnO2 (2x2 tunnel structure) nanorods and δ-MnO2 (2-D layered structure) nano-fiber clumps were synthesized in a facile way in an aqueous solution and characterized by TEM, FE-SEM, XRD and BET-N2 adsorption techniques. The structural analysis shows that α-MnO2 is needle shaped nanorods and δ-MnO2 consists of 2-D platelets of fine needle-like fibers arranged in ball-like aggregates. Further batch experiments confirmed that both nanoadsorbents are potential candidates for the adsorption of As(V) with a capacity of 19.41 and 15.33 mg g-1 for α-MnO2 and δ-MnO2, respectively. The presence of As3d peak in XPS study indicates that arsenic on the surface of nanoadsorbents is in the stable form of As(V) with a percentage of arsenate onto α-MnO2 is 0.099% as compared to 0.021% onto δ-MnO2, clearly indicating the higher adsorption of As(V) in case of α-MnO2 as compared to δ-MnO2, which is in good agreement with the adsorption studies results. Display Omitted

  5. The effect of copper and gallium compounds on ribonucleotide reductase

    Energy Technology Data Exchange (ETDEWEB)

    Narasimhan, J.

    1992-01-01

    The mode of action of copper complexes (CuL and CuKTS) and gallium compounds (gallium nitrate and citrate) in cytotoxicity was studied. The effects of these agents on the enzyme ribonucleotide reductase was investigated by monitoring the tyrosyl free radical present in the active site of the enzyme through electron spin resonance (ESR) spectroscopy. Ribonucleotide reductase, a key enzyme in cellular proliferation, consists of two subunits. M1, a dimer of molecular weight 170,000 contains the substrate and effector binding sites. M2, a dimer of molecular weight 88,000, contains non-heme iron and tyrosyl free radical essential for the activity of the enzyme. In studies using copper complexes, the cellular oxidative chemistry was examined by ESR studies on adduct formation with membranes, and oxidation of thiols. Membrane thiols were oxidized through the reduction of the ESR signal of the thiol adduct and the analysis of sulfhydryl content. Using the radiolabel [sup 59]Fe, the inhibitory action of copper thiosemicarbazones on cellular iron uptake was shown. The inhibitory action of CuL on ribonucleotide reductase was shown by the quenching of the tyrosyl free radical on the M2 subunit. The hypothesis that gallium directly interacts with the M2 subunit of the enzyme and displaces the iron from it was proven. The tyrosyl free radical signal from cell lysates was inhibited by the direct addition of gallium compounds. Gallium content in the cells was measured by a fluorimetric method, to ensure the presence of sufficient amounts of gallium to compete with the iron in the M2 subunit. The enzyme activity, measured by the conversion of [sup 14]C-CDP to the labeled deoxy CDP, was inhibited by the addition of gallium nitrate in a cell free assay system. The immunoprecipitation studies of the [sup 59]Fe labeled M2 protein using the monoclonal antibody directed against this subunit suggested that gallium releases iron from the M2 subunit.

  6. biliverdin. Is there a role for biliverdin reductase?

    Directory of Open Access Journals (Sweden)

    AndreasDaiber

    2012-03-01

    Full Text Available Reactive oxygen species (ROS and signaling events are involved in the pathogenesis of endothelial dysfunction and represent a major contribution to vascular regulation. Molecular signaling is highly dependent on reactive oxygen species. But depending on the amount of ROS production it might have toxic or protective effects. Despite a large number of negative outcomes in large clinical trials (e.g. HOPE, HOPE-TOO, antioxidant molecules and agents are important players to influence the critical balance between production and elimination of RONS. However, chronic systemic antioxidant therapy lacks clinical efficacy, probably by interfering with important physiological redox signaling pathways. Therefore, it may be a much more promising attempt to induce intrinsic antioxidant pathways in order to increase the antioxidants not systemically but at the place of oxidative stress and complications. Among others, heme oxygenase (HO has been shown to be important for attenuating the overall production of ROS in a broad range of disease states through its ability to degrade heme and to produce carbon monoxide (CO, biliverdin/bilirubin, and the release of free iron with subsequent ferritin induction. With the present review we would like to highlight the important antioxidant role of the heme oxygenase system and especially discuss the contribution of the biliverdin, bilirubin and biliverdin reductase to these beneficial effects. The bilierdin reductase was reported to confer an antioxidant redox amplification cycle by which low, physiological bilirubin concentrations confer potent antioxidant protection via recycling of biliverdin from oxidized bilirubin by the biliverdin reductase, linking this sink for oxidants to the NADPH pool. To date the existence and role of this antioxidant redox cycle is still under debate and we present and discuss the pros and cons as well as our own findings on this topic.

  7. Macrophage Heterogeneity in Respiratory Diseases

    Directory of Open Access Journals (Sweden)

    Carian E. Boorsma

    2013-01-01

    Full Text Available Macrophages are among the most abundant cells in the respiratory tract, and they can have strikingly different phenotypes within this environment. Our knowledge of the different phenotypes and their functions in the lung is sketchy at best, but they appear to be linked to the protection of gas exchange against microbial threats and excessive tissue responses. Phenotypical changes of macrophages within the lung are found in many respiratory diseases including asthma, chronic obstructive pulmonary disease (COPD, and pulmonary fibrosis. This paper will give an overview of what macrophage phenotypes have been described, what their known functions are, what is known about their presence in the different obstructive and restrictive respiratory diseases (asthma, COPD, pulmonary fibrosis, and how they are thought to contribute to the etiology and resolution of these diseases.

  8. Submersion and acute respiratory failure

    Institute of Scientific and Technical Information of China (English)

    Yu-Jang Su

    2014-01-01

    Objectives:To know the relationship between hypothermia, etiology, respiratory failure and prognosis of submersion in environmental emergency medicine.Methods:FromDecember1, 2002 toSeptember30,2007, there were52 hospitalized near- drowning cases in a medical center at northernTaiwan.Retrospective study of52 submersion patients who were hospitalized during the duration was analyzed.Results:The hypothermic groups are more commonly seen in acute respiratory failure after submersion,36%vs.21%,P<0.05.The hypothermic submersion patients who are older in age than normothermic submersion patients(44vs.27 years old,P<0.05).The suicidal submersion patients are older, hypothermic and longer length of stay than accidental submersion patients.Conclusions:Submersion patients who are hypothermic on arrival of emergency department(ED) are risky to respiratory failure and older, more hypothermic, longer hospital stay in suicidal submersion patients.

  9. Electron/proton coupling in bacterial nitric oxide reductase during reduction of oxygen.

    Science.gov (United States)

    Flock, Ulrika; Watmough, Nicholas J; Adelroth, Pia

    2005-08-01

    The respiratory nitric oxide reductase (NOR) from Paracoccus denitrificans catalyzes the two-electron reduction of NO to N(2)O (2NO + 2H(+) + 2e(-) --> N(2)O + H(2)O), which is an obligatory step in the sequential reduction of nitrate to dinitrogen known as denitrification. NOR has four redox-active cofactors, namely, two low-spin hemes c and b, one high-spin heme b(3), and a non-heme iron Fe(B), and belongs to same superfamily as the oxygen-reducing heme-copper oxidases. NOR can also use oxygen as an electron acceptor; this catalytic activity was investigated in this study. We show that the product in the steady-state reduction of oxygen is water. A single turnover of the fully reduced NOR with oxygen was initiated using the flow-flash technique, and the progress of the reaction monitored by time-resolved optical absorption spectroscopy. Two major phases with time constants of 40 micros and 25 ms (pH 7.5, 1 mM O(2)) were observed. The rate constant for the faster process was dependent on the O(2) concentration and is assigned to O(2) binding to heme b(3) at a bimolecular rate constant of 2 x 10(7) M(-)(1) s(-)(1). The second phase (tau = 25 ms) involves oxidation of the low-spin hemes b and c, and is coupled to the uptake of protons from the bulk solution. The rate constant for this phase shows a pH dependence consistent with rate limitation by proton transfer from an internal group with a pK(a) = 6.6. This group is presumably an amino acid residue that is crucial for proton transfer to the catalytic site also during NO reduction. PMID:16060680

  10. Autoimmunity in Membranous Nephropathy Targets Aldose Reductase and SOD2

    OpenAIRE

    Prunotto, Marco; Carnevali, Maria Luisa; Candiano, Giovanni; Murtas, Corrado; Bruschi, Maurizio; Corradini, Emilia; Trivelli, Antonella; Magnasco, Alberto; Petretto, Andrea; Santucci, Laura; Mattei, Silvia; Gatti, Rita; Scolari, Francesco; Kador, Peter; Allegri, Landino

    2010-01-01

    Glomerular targets of autoimmunity in human membranous nephropathy are poorly understood. Here, we used a combined proteomic approach to identify specific antibodies against podocyte proteins in both serum and glomeruli of patients with membranous nephropathy (MN). We detected specific anti–aldose reductase (AR) and anti–manganese superoxide dismutase (SOD2) IgG4 in sera of patients with MN. We also eluted high titers of anti-AR and anti-SOD2 IgG4 from microdissected glomeruli of three biopsi...

  11. Applications of Carboxylic Acid Reductases in Oleaginous Microbes

    Energy Technology Data Exchange (ETDEWEB)

    Resch, Michael G.; Linger, Jeffrey; McGeehan, John; Tyo, Keith; Beckham, Gregg

    2016-04-24

    Carboxylic acid reductases (CARs) are recently emerging reductive enzymes for the direct production of aldehydes from biologically-produced carboxylic acids. Recent work has demonstrated that these powerful enzymes are able to reduce a very broad range of volatile- to long-chain fatty acids as well as aromatic acids. Here, we express four CAR enzymes from different fungal origins to test their activity against fatty acids commonly produced in oleaginous microbes. These in vitro results will inform metabolic engineering strategies to conduct mild biological reduction of carboxylic acids in situ, which is conventionally done via hydrotreating catalysis at high temperatures and hydrogen pressures.

  12. Mediated electrochemistry of dimethyl sulfoxide reductase promoted by carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    BERNHARDT; Paul; V

    2010-01-01

    Mediated electrochemistry of dimethyl sulfoxide reductase from Rhodobacter capsulatus (DMSOR) which is immobilized on a bare glassy carbon (GC) electrode and a carbon nanotube (CNT)-modified GC electrode was studied using the Co complex (trans-6,13-dimethyl-1,4,8,11-tetraazacyclotetradecane-6,13-diamine)cobalt(III) ([Co(trans-diammac)] +) as a mediator.The cyclic voltammograms of different electrodes were carried out at different substrate (DMSO) concentrations.The results demonstrated that the catalytic current was increased by employing CNT as a promoter.

  13. Vibrio harveyi Nitroreductase Is Also a Chromate Reductase

    OpenAIRE

    Kwak, Young Hak; Lee, Dong Seok; Kim, Han Bok

    2003-01-01

    The chromate reductase purified from Pseudomonas ambigua was found to be homologous with several nitroreductases. Escherichia coli DH5α and Vibrio harveyi KCTC 2720 nitroreductases were chosen for the present study, and their chromate-reducing activities were determined. A fusion between glutathione S-transferase (GST) and E. coli DH5α NfsA (GST-EcNfsA), a fusion between GST and E. coli DH5α NfsB (GST-EcNfsB), and a fusion between GST and V. harveyi KCTC 2720 NfsA (GST-VhNfsA) were prepared f...

  14. Pulse radiolysis studies on superoxide reductase from Treponema pallidum.

    OpenAIRE

    Nivière, V; Lombard, M.; Fontecave, M.; Houée-Levin, C

    2001-01-01

    Superoxide reductases (SORs) are small metalloenzymes, which catalyze reduction of O2*- to H2O2. The reaction of the enzyme from Treponema pallidum with superoxide was studied by pulse radiolysis methods. The first step is an extremely fast bi-molecular reaction of the ferrous center with O2, with a rate constant of 6 x 10 (8) M(-1) s(-1). A first intermediate is formed which is converted to a second one with a slower rate constant of 4800 s(-1). This latter value is 10 times higher than the ...

  15. Methylenetetrahydrofolate reductase (MTHFR) deficiency presenting as a rash.

    LENUS (Irish Health Repository)

    Crushell, Ellen

    2012-09-01

    We report on the case of a 2-year-old girl recently diagnosed with Methylenetetrahydrofolate reductase (MTHFR) deficiency who originally presented in the neonatal period with a distinctive rash. At 11 weeks of age she developed seizures, she had acquired microcephaly and developmental delay. The rash deteriorated dramatically following commencement of phenobarbitone; both rash and seizures abated following empiric introduction of pyridoxine and folinic acid as treatment of possible vitamin responsive seizures. We postulate that phenobarbitone in combination with MTHFR deficiency may have caused her rash to deteriorate and subsequent folinic acid was helpful in treating the rash and preventing further acute neurological decline as commonly associated with this condition.

  16. Respiratory disease surveillance in Hungary

    Energy Technology Data Exchange (ETDEWEB)

    Agocs, M.M.; Rudnai, P.; Etzel, R.A. (Division of Environmental Hazards and Health Effects, Centers for Disease Control, Budapest (Hungary))

    1992-08-28

    In October 1989, the Hungarian National Institute of Hygiene initiated the Children's Acute Respiratory Morbidity (CHARM) Surveillance System to assess the association between nine reportable respiratory diseases and air pollution. The weekly number of physician-diagnosed, reportable respiratory diseases among four age groups of children (less than 1, 1-2, 3-5, and 6-14 years) was tabulated for Sopron, a city with 60,000 residents. We calculated the proportion of diseases occurring during weeks with low, moderate, and high sulfur dioxide (SO2) and nitrogen dioxide (NO2) concentrations. The weekly averages of the 24-hour median SO2 concentrations were divided into thirds at less than or equal to 17.6, greater than 17.6 to less than or equal to 26.3, and greater than 26.3 micrograms/m3 (range: 0.9-79.6 micrograms/m3), and the NO2 concentrations at less than or equal to 29.8, greater than 29.8 to less than or equal to 44.1, and greater than 44.1 micrograms/m3 (range: 4.2-90.1 micrograms/m3). During 1990, 11,474 respiratory disease cases occurred among the 4,020 children less than 15 years of age living in Sopron and monitored by the CHARM system. The two most frequently reported disease categories were rhinitis/tonsillitis/pharyngitis (71.5%) and acute bronchitis (8.5%). Sixty-seven percent of pneumonia cases occurred when SO2 concentrations were highest. We found no association between levels of NO2 and respiratory diseases. The CHARM Surveillance System may characterize more fully which groups of children develop particular respiratory diseases following exposure to air pollution.

  17. Respiratory tract infection during Hajj

    Directory of Open Access Journals (Sweden)

    Alzeer Abdulaziz

    2009-01-01

    Full Text Available Respiratory tract infection during Hajj (pilgrimage to Mecca is a common illness, and it is responsible for most of the hospital admissions. Influenza virus is the leading cause of upper respiratory tract infection during Hajj, and pneumonia can be serious. Taking into account the close contacts among the pilgrims, as well as the crowding, the potential for transmission of M. tuberculosis is expected to be high. These pilgrims can be a source for spreading infection on their return home. Although vaccination program for influenza is implemented, its efficacy is uncertain in this religious season. Future studies should concentrate on prevention and mitigation of these infections.

  18. Evaluation of 5α-reductase inhibitory activity of certain herbs useful as antiandrogens.

    Science.gov (United States)

    Nahata, A; Dixit, V K

    2014-08-01

    This study demonstrates 5α-reductase inhibitory activity of certain herbs useful in the management of androgenic disorders. Ganoderma lucidum (Curtis) P. Karst (GL), Urtica dioica Linn. (UD), Caesalpinia bonducella Fleming. (CB), Tribulus terrestris Linn. (TT), Pedalium murex Linn. (PM), Sphaeranthus indicus Linn. (SI), Cuscuta reflexa Roxb. (CR), Citrullus colocynthis Schrad. (CC), Benincasa hispida Cogn. (BH), Phyllanthus niruri Linn. (PN) and Echinops echinatus Linn. (EE) were included in the study. Petroleum ether, ethanol and aqueous extracts of these herbs were tested for their 5α-reductase inhibitory activity against the standard 5α-reductase inhibitor, finasteride. A biochemical method to determine the activity of 5α-reductase was used to evaluate the inhibition of different extracts to the enzyme. The optical density (OD) value of each sample was measured continuously with ultraviolet spectrophotometer for the reason that the substrate NADPH has a specific absorbance at 340 nm. As the enzyme 5α-reductase uses NADPH as a substrate, so in the presence of 5α-reductase inhibitor, the NADPH concentration will increase with the function of time. This method thus implicates the activity of 5α-reductase. The method proved to be extremely useful to screen the herbs for their 5α-reductase inhibitory potential. GL, UD, BH, SI and CR came out to be promising candidates for further exploring their antiandrogenic properties. PMID:23710567

  19. Determination of the specific activities of methionine sulfoxide reductase A and B by capillary electrophoresis

    Science.gov (United States)

    A capillary electrophoresis (CE) method for the determination of methionine sulfoxide reductase A and methionine sulfoxide reductase B activities in mouse liver is described. The method is based on detection of the 4-(dimethylamino)azobenzene-4’-sulfonyl derivative of L-methionine (dabsyl Met), the ...

  20. Sucrose mimics the light induction of Arabidopsis nitrate reductase gene transcription

    DEFF Research Database (Denmark)

    Cheng, Chi-Lien; Acedo, Gregoria N; Kristensen, Michael;

    1992-01-01

    Nitrate reductase, the first enzyme in nitrate assimilation, is located at the crossroad of two energy-consuming pathways: nitrate assimilation and carbon fixation. Light, which regulates the expression of many higher-plant carbon fixation genes, also regulates nitrate reductase gene expression. ...

  1. Functions of Flavin Reductase and Quinone Reductase in 2,4,6-Trichlorophenol Degradation by Cupriavidus necator JMP134▿

    OpenAIRE

    Belchik, Sara Mae; Xun, Luying

    2007-01-01

    The tcpRXABCYD operon of Cupriavidus necator JMP134 is involved in the degradation of 2,4,6-trichlorophenol (2,4,6-TCP), a toxic pollutant. TcpA is a reduced flavin adenine dinucleotide (FADH2)-dependent monooxygenase that converts 2,4,6-TCP to 6-chlorohydroxyquinone. It has been implied via genetic analysis that TcpX acts as an FAD reductase to supply TcpA with FADH2, whereas the function of TcpB in 2,4,6-TCP degradation is still unclear. In order to provide direct biochemical evidence for t...

  2. MEK2 regulates ribonucleotide reductase activity through functional interaction with ribonucleotide reductase small subunit p53R2

    OpenAIRE

    Piao, Chunmei; Youn, Cha-Kyung; Jin, Min; Yoon, Sang Pil; Chang, In-Youb; Lee, Jung Hee; You, Ho Jin

    2012-01-01

    The p53R2 protein, a newly identified member of the ribonucleotide reductase family that provides nucleotides for DNA damage repair, is directly regulated by p53. We show that p53R2 is also regulated by a MEK2 (ERK kinase 2/MAP kinase kinase 2)-dependent pathway. Increased MEK1/2 phosphorylation by serum stimulation coincided with an increase in the RNR activity in U2OS and H1299 cells. The inhibition of MEK2 activity, either by treatment with a MEK inhibitor or by transfection with MEK2 siRN...

  3. The effect of ionic and non-ionic surfactants on the growth, nitrate reductase and nitrite reductase activities of Spirodela polyrrhiza (L. Schleiden

    Directory of Open Access Journals (Sweden)

    Józef Buczek

    2014-02-01

    Full Text Available Inclusion into the medium of 5 mg•dm-3 of non-ionic (ENF or ionic (DBST surfactant caused 50-60% inhibition of nitrite reductase MR activity in S. polyrrhiza. At the same time, increased accumulation of NO2- in the plant tissues and lowering of the total and soluble protein contents were found. DBST also lowered the nitrate reductase (NR activity and the dry mass of the plants.

  4. Co-Expression of Monodehydroascorbate Reductase and Dehydroascorbate Reductase from Brassica rapa Effectively Confers Tolerance to Freezing-Induced Oxidative Stress

    OpenAIRE

    Shin, Sun-Young; Kim, Myung-Hee; Kim, Yul-Ho; Park, Hyang-Mi; Yoon, Ho-Sung

    2013-01-01

    Plants are exposed to various environmental stresses and have therefore developed antioxidant enzymes and molecules to protect their cellular components against toxicity derived from reactive oxygen species (ROS). Ascorbate is a very important antioxidant molecule in plants, and monodehydroascorbate reductase (MDHAR; EC 1.6.5.4) and dehydroascorbate reductase (DHAR; EC 1.8.5.1) are essential to regeneration of ascorbate for maintenance of ROS scavenging ability. The MDHAR and DHAR genes from ...

  5. Optimisation of nitrate reductase enzyme activity to synthesise silver nanoparticles.

    Science.gov (United States)

    Khodashenas, Bahareh; Ghorbani, Hamid Reza

    2016-06-01

    Today, the synthesis of silver nanoparticles (Ag NPs) is very common since it has many applications in different areas. The synthesis of these nanoparticles is done by means of physical, chemical, or biological methods. However, due to its inexpensive and environmentally friendly features, the biological method is more preferable. In the present study, using nitrate reductase enzyme available in the Escherichia coli (E. coli) bacterium, the biosynthesis of Ag NPs was investigated. In addition, the activity of the nitrate reductase enzyme was optimised by changing its cultural conditions, and the effects of silver nitrate (AgNO3) concentration and enzyme amount on nanoparticles synthesis were studied. Finally, the produced nanoparticles were studied using ultraviolet -visible (UV-Vis) spectrophotometer, dynamic light scattering technique, and transmission electron microscopy. UV-Visible spectrophotometric study showed the characteristic peak for Ag NPs at wavelength 405-420 nm for 1 mM metal precursor solution (AgNO3) with 1, 5, 10, and 20 cc supernatant and 435 nm for 0.01M AgNO3 with 20 cc supernatant. In this study, it was found that there is a direct relationship between the AgNO3 concentration and the size of produced Ag NPs. PMID:27256897

  6. Azotobacter vinelandii NADPH:ferredoxin reductase cloning, sequencing, and overexpression.

    Science.gov (United States)

    Isas, J M; Yannone, S M; Burgess, B K

    1995-09-01

    Azotobacter vinelandii ferredoxin I (AvFdI) controls the expression of another protein that was originally designated Protein X. Recently we reported that Protein X is a NADPH-specific flavoprotein that binds specifically to FdI (Isas, J.M., and Burgess, B.K. (1994) J. Biol. Chem. 269, 19404-19409). The gene encoding this protein has now been cloned and sequenced. Protein X is 33% identical and has an overall 53% similarity with the fpr gene product from Escherichia coli that encodes NADPH:ferredoxin reductase. On the basis of this similarity and the similarity of the physical properties of the two proteins, we now designate Protein X as A. vinelandii NADPH:ferredoxin reductase and its gene as the fpr gene. The protein has been overexpressed in its native background in A. vinelandii by using the broad host range multicopy plasmid, pKT230. In addition to being regulated by FdI, the fpr gene product is overexpressed when A. vinelandii is grown under N2-fixing conditions even though the fpr gene is not preceded by a nif specific promoter. By analogy to what is known about fpr expression in E. coli, we propose that FdI may exert its regulatory effect on fpr by interacting with the SoxRS regulon. PMID:7673160

  7. Nitrate metabolism in tobacco leaves overexpressing Arabidopsis nitrite reductase.

    Science.gov (United States)

    Davenport, Susie; Le Lay, Pascaline; Sanchez-Tamburrrino, Juan Pablo

    2015-12-01

    Primary nitrogen assimilation in plants includes the reduction of nitrite to ammonium in the chloroplasts by the enzyme nitrite reductase (NiR EC:1.7.7.1) or in the plastids of non-photosynthetic organs. Here we report on a study overexpressing the Arabidopsis thaliana NiR (AtNiR) gene in tobacco plants under the control of a constitutive promoter (CERV - Carnation Etched Ring Virus). The aim was to overexpress AtNiR in an attempt to alter the level of residual nitrite in the leaf which can act as precursor to the formation of nitrosamines. The impact of increasing the activity of AtNiR produced an increase in leaf protein and a stay-green phenotype in the primary transformed AtNiR population. Investigation of the T1 homozygous population demonstrated elevated nitrate reductase (NR) activity, reductions in leaf nitrite and nitrate and the amino acids proline, glutamine and glutamate. Chlorophyl content of the transgenic lines was increased, as evidenced by the stay-green phenotype. This reveals the importance of NiR in primary nitrogen assimilation and how modification of this key enzyme affects both the nitrogen and carbon metabolism of tobacco plants. PMID:26447683

  8. Pinpointing a Mechanistic Switch Between Ketoreduction and "Ene" Reduction in Short-Chain Dehydrogenases/Reductases.

    Science.gov (United States)

    Lygidakis, Antonios; Karuppiah, Vijaykumar; Hoeven, Robin; Ní Cheallaigh, Aisling; Leys, David; Gardiner, John M; Toogood, Helen S; Scrutton, Nigel S

    2016-08-01

    Three enzymes of the Mentha essential oil biosynthetic pathway are highly homologous, namely the ketoreductases (-)-menthone:(-)-menthol reductase and (-)-menthone:(+)-neomenthol reductase, and the "ene" reductase isopiperitenone reductase. We identified a rare catalytic residue substitution in the last two, and performed comparative crystal structure analyses and residue-swapping mutagenesis to investigate whether this determines the reaction outcome. The result was a complete loss of native activity and a switch between ene reduction and ketoreduction. This suggests the importance of a catalytic glutamate vs. tyrosine residue in determining the outcome of the reduction of α,β-unsaturated alkenes, due to the substrate occupying different binding conformations, and possibly also to the relative acidities of the two residues. This simple switch in mechanism by a single amino acid substitution could potentially generate a large number of de novo ene reductases. PMID:27411040

  9. Trypanothione Reductase: A Viable Chemotherapeutic Target for Antitrypanosomal and Antileishmanial Drug Design

    Directory of Open Access Journals (Sweden)

    M. Omar F. Khan

    2007-01-01

    Full Text Available Trypanosomiasis and leishmaniasis are two debilitating disease groups caused by parasites of Trypanosoma and Leishmania spp. and affecting millions of people worldwide. A brief outline of the potential targets for rational drug design against these diseases are presented, with an emphasis placed on the enzyme trypanothione reductase. Trypanothione reductase was identified as unique to parasites and proposed to be an effective target against trypanosomiasis and leishmaniasis. The biochemical basis of selecting this enzyme as a target, with reference to the simile and contrast to human analogous enzyme glutathione reductase, and the structural aspects of its active site are presented. The process of designing selective inhibitors for the enzyme trypanothione reductase has been discussed. An overview of the different chemical classes of inhibitors of trypanothione reductase with their inhibitory activities against the parasites and their prospects as future chemotherapeutic agents are briefl y revealed.

  10. Hypoventilatory respiratory failure in generalised scleroderma

    OpenAIRE

    Iliffe, Gerald D; Pettigrew, Norman M

    1983-01-01

    A patient with generalised cutaneous and gastrointestinal scleroderma subsequently died from respiratory failure secondary to hyperventilation. At necropsy changes consistent with scleroderma of the diaphragm were found; these were thought to have contributed appreciably to the terminal respiratory failure.

  11. Cystic Fibrosis (CF) Respiratory Screen: Sputum

    Science.gov (United States)

    ... Tropical Delight: Melon Smoothie Pregnant? Your Baby's Growth Cystic Fibrosis (CF) Respiratory Screen: Sputum KidsHealth > For Parents > Cystic Fibrosis (CF) Respiratory Screen: Sputum Print A A A ...

  12. Molecular detection of respiratory viruses: clinical impact

    NARCIS (Netherlands)

    van de Pol, A.C.

    2009-01-01

    Viral respiratory tract infections (LRTIs) cause major morbidity in infants and children. Traditionally, respiratory viruses are detected with conventional tests (viral culture and direct immunofluorescence (DIF)), however nowadays viral diagnostics are being revolutionized by the increased implemen

  13. House Dust Mite Respiratory Allergy

    DEFF Research Database (Denmark)

    Calderón, Moisés A; Kleine-Tebbe, Jörg; Linneberg, Allan;

    2015-01-01

    Although house dust mite (HDM) allergy is a major cause of respiratory allergic disease, specific diagnosis and effective treatment both present unresolved challenges. Guidelines for the treatment of allergic rhinitis and asthma are well supported in the literature, but specific evidence on the...

  14. Health Instruction Packages: Respiratory Therapy.

    Science.gov (United States)

    Lavich, Margot; And Others

    Text, illustrations, and exercises are utilized in these four learning modules to teach respiratory therapy students a variety of job-related skills. The first module, "Anatomy and Physiology of the Central Controls of Respiration" by Margot Lavich, describes the functions of the five centers of the brain that control respiration and identifies…

  15. Guide to industrial respiratory protection

    International Nuclear Information System (INIS)

    The Occupational Safety and Health Act of 1970 has increased the emphasis on proper selection and use of respirators in situations where engineering controls are not feasible or are being implemented. Although a great deal of information on respiratory protection has been published, most of it is more technical than necessary for the average user faced with day-to-day problems of respiratory protection in industrial environments. This Guide is to provide the industrial user a single reference source containing enough information for establishing and maintaining a respirator program that meets the OSHA requirements outlined in 29 CFR Part 1910.134. It includes chapters on respirator selection, use, maintenance, and inspection, a complete description of all types of respirators and their advantages and limitations, and chapters on respirator fitting and wearer training, respiratory physiology, respiratory hazards, and physiological and psychological limitations. Also included are samples of the decision logic used in respirator selection, guidance on setting up an adequate respirator program through formulation of written standard operating procedures, and discussion of the meaning of the approved respirator

  16. Detection of Respiratory Viruses by Molecular Methods

    OpenAIRE

    Mahony, James B.

    2008-01-01

    Summary: Clinical laboratories historically diagnose seven or eight respiratory virus infections using a combination of techniques including enzyme immunoassay, direct fluorescent antibody staining, cell culture, and nucleic acid amplification tests. With the discovery of six new respiratory viruses since 2000, laboratories are faced with the challenge of detecting up to 19 different viruses that cause acute respiratory disease of both the upper and lower respiratory tracts. The application o...

  17. Introduction to circulatory and respiratory system modeling

    OpenAIRE

    Ferrari, Gianfranco; Darowski, Marek; Golczewski, Tomasz; Gorczynska, Krystyna; Kozarski, Maciej

    2010-01-01

    This chapter is focused on circulatory and respiratory system modeling. It includes a brief history of circulatory and respiratory system modeling development and a short description of the state of art. In the chapter also basic classification of mechanical circulatory and respiratory assistance is presented. The last part of the chapter deals with innovative approaches to modeling of both circulatory and respiratory system which concern hybrid models and virtual organs. Hybrid modeling cons...

  18. Effects of Aging on the Respiratory System.

    Science.gov (United States)

    Levitzky, Michael G.

    1984-01-01

    Relates alterations in respiratory system functions occurring with aging to changes in respiratory system structure during the course of life. Main alterations noted include loss of alveolar elastic recoil, alteration in chest wall structure and decreased respiratory muscle strength, and loss of surface area and changes in pulmonary circulation.…

  19. Atypical respiratory complications of dengue fever

    Institute of Scientific and Technical Information of China (English)

    Naveen Kumar; AK Gadpayle; Deepshikha Trisal

    2013-01-01

    In last decade, dengue has emerged as one of the most important vector born disease.With increasing cases, uncommon presentations and complications are now commonly recognized. Here, we report two cases of rare pattern of respiratory involvement in dengue: acute respiratory distress syndrome and bronchiolitis with respiratory failure.

  20. Functional complementation of a nitrate reductase defective mutant of a green alga Dunaliella viridis by introducing the nitrate reductase gene.

    Science.gov (United States)

    Sun, Yu; Gao, Xiaoshu; Li, Qiyun; Zhang, Qingqi; Xu, Zhengkai

    2006-08-01

    Nitrate reductase (NR) catalyzes NAD (P) H dependent reduction of nitrate to nitrite. Transformation systems have been established in several species of green algae by nitrate reductase gene functional complementation. In this report, an endogenous NR cDNA (3.4 kb) and a genomic fragment (14.6 kb) containing the NR gene (DvNIA1) were isolated from the D. viridis cDNA and genomic libraries respectively. Southern blot and Northern blot analyses showed that this gene exists as a single copy in D. viridis and is induced by nitrate. To obtain a NR defective mutant as a recipient strain, D. viridis cells were treated with a chemical mutagen and then cultured on a chlorate-containing plate to enrich chlorate tolerant mutants. Southern analysis showed that one isolate, B14, had a deletion in the DvNIA1 gene region. Using electroporation conditions determined in this laboratory, plasmid pDVNR containing the intact DvNIA1 gene has been electroporated into the defective mutant B14. Strains retaining a nitrate assimilation phenotype were obtained from nitrate plates after spreading the electroporated cells. In some individual strains, transcription of the introduced gene was detected. NR activity in these strains was slightly higher than that in the defective B14 cell, but excretion of nitrite into culture media was almost as high as that of the wild-type cell. Possible episomal presence of the introduced DNA in D. viridis is discussed. PMID:16797881

  1. Postperfusion lung syndrome: Respiratory mechanics, respiratory indices and biomarkers

    OpenAIRE

    Shi-Min Yuan

    2015-01-01

    Postperfusion lung syndrome is rare but lethal. Secondary inflammatory response was the popularly accepted theory for the underlying etiology. Respiratory index (RI) and arterial oxygen tension/fractional inspired oxygen can be reliable indices for the diagnosis of this syndrome as X-ray appearance is always insignificant at the early stage of the onset. Evaluations of extravascular lung water content and pulmonary compliance are also helpful in the definite diagnosis. Multiorgan failure and ...

  2. Vibrio harveyi Nitroreductase Is Also a Chromate Reductase

    Science.gov (United States)

    Kwak, Young Hak; Lee, Dong Seok; Kim, Han Bok

    2003-01-01

    The chromate reductase purified from Pseudomonas ambigua was found to be homologous with several nitroreductases. Escherichia coli DH5α and Vibrio harveyi KCTC 2720 nitroreductases were chosen for the present study, and their chromate-reducing activities were determined. A fusion between glutathione S-transferase (GST) and E. coli DH5α NfsA (GST-EcNfsA), a fusion between GST and E. coli DH5α NfsB (GST-EcNfsB), and a fusion between GST and V. harveyi KCTC 2720 NfsA (GST-VhNfsA) were prepared for their overproduction and easy purification. GST-EcNfsA, GST-EcNFsB, and GST-VhNFsA efficiently reduced nitrofurazone and 2,4,6-trinitrotoluene (TNT) as their nitro substrates. The Km values for GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA for chromate reduction were 11.8, 23.5, and 5.4 μM, respectively. The Vmax values for GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA were 3.8, 3.9, and 10.7 nmol/min/mg of protein, respectively. GST-VhNfsA was the most effective of the three chromate reductases, as determined by each Vmax/Km value. The optimal temperatures of GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA for chromate reduction were 55, 30, and 30°C, respectively. Thus, it is confirmed that nitroreductase can also act as a chromate reductase. Nitroreductases may be used in chromate remediation. GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA have a molecular mass of 50 kDa and exist as a monomer in solution. Thin-layer chromatography showed that GST-EcNfsA, GST-EcNfsB, and GST-VhNfsA contain FMN as a cofactor. GST-VhNfsA reduced Cr(VI) to Cr(III). Cr(III) was much less toxic to E. coli than Cr(VI). PMID:12902220

  3. Habituation in neural processing and subjective perception of respiratory sensations

    OpenAIRE

    von Leupoldt, Andreas; Vovk, Andrea; Bradley, Margaret M.; Lang, Peter J.; Davenport, Paul W.

    2010-01-01

    Reduced perception of respiratory sensations is associated with negative treatment outcome in asthma. We examined whether habituation in the neural processing of repeatedly experienced respiratory sensations may underlie subjective reports of reduced respiratory perception. Respiratory-related evoked potentials (RREP) elicited by inspiratory occlusions and reports of respiratory perception were compared between early and late experimental periods in healthy subjects. Reports of respiratory pe...

  4. In silico analysis of bacterial arsenic islands reveals remarkable synteny and functional relatedness between arsenate and phosphate

    DEFF Research Database (Denmark)

    Li, Hang; Li, Mingshun; Huang, Yinyan; Rensing, Christopher Günther T; Wang, Gejiao

    2013-01-01

    In order to construct a more universal model for understanding the genetic requirements for bacterial AsIII oxidation, an in silico examination of the available sequences in the GenBank was assessed and revealed 21 conserved 5-71 kb arsenic islands within phylogenetically diverse bacterial genomes....... The arsenic islands included the AsIII oxidase structural genes aioBA, ars operons (e.g., arsRCB) which code for arsenic resistance, and pho, pst, and phn genes known to be part of the classical phosphate stress response and that encode functions associated with regulating and acquiring organic and...... likely the arsenic islands did not evolve as a whole unit but formed independently by acquisition of functionally related genes and operons in respective strains. Considering gene synteny and structural analogies between arsenate and phosphate, we presumed that these genes function together in helping...

  5. CHROMATED COPPER ARSENATE (CCA TREATED WOOD: DESTINATION OPTIONS FOR WASTES GENERATED AND PERSPECTIVES IN THE DEVELOPMENT OF METHODOLOGIES FOR TOXIC ELEMENTS REMOVAL

    Directory of Open Access Journals (Sweden)

    PIRES, Marçal

    2015-01-01

    Full Text Available The wood has been used for various functions, one of them is the manufacture of poles for electrification and telephony. However, this material has a big propensity to deteriorate. To increase its durability, some alternatives are employed, one of them is the incorporation of toxic substances (preservatives to protect the wood from agents such as fungi, bacteria and xylophagous insects that cause its decay. Currently, the preservative chromated copper arsenate (CCA is the most widely used for this purpose. However, when the CCA treated wood poles reach the end of their useful life, they become hazardous waste due to the presence of chromium and arsenic. In this work are presented the main methodologies for treatment, destination options and adequate disposal of these wastes, as well as different methods for toxic elements removal from the CCA-treated wood

  6. Biogeochemical reductive release of soil embedded arsenate around a crater area (Guandu) in northern Taiwan using X-ray absorption near-edge spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Kai-Ying Chiang; Tsan-Yao Chen; Chih-Hao Lee; Tsang-Lang Lin; Ming-Kuang Wang; Ling-Yun Jang; Jyh-Fu Lee

    2013-01-01

    This study investigates biogeochemical reductive release of arsenate from beudantite into solution in a crater area in northern Taiwan,using a combination of X-ray absorption near-edge structure (XANES) and atomic absorption spectrometry.Total arsenic (As)concentrations in the soil were more than 200 mg/kg.Over four months of laboratory experiments,less than 0.8% As was released into solution after reduction experiments.The 71% to 83% As was chemically reduced into arsenite (As(Ⅲ)) and partially weathering into the soluble phase.The kinetic dissolution and re-precipitation of As,Fe,Pb and sulfate in this area of paddy soils merits further study.

  7. Structure of a bacterial homologue of vitamin K epoxide reductase

    Energy Technology Data Exchange (ETDEWEB)

    Li, Weikai; Schulman, Sol; Dutton, Rachel J.; Boyd, Dana; Beckwith, Jon; Rapoport, Tom A. (Harvard-Med); (HHMI)

    2010-03-19

    Vitamin K epoxide reductase (VKOR) generates vitamin K hydroquinone to sustain {gamma}-carboxylation of many blood coagulation factors. Here, we report the 3.6 {angstrom} crystal structure of a bacterial homologue of VKOR from Synechococcus sp. The structure shows VKOR in complex with its naturally fused redox partner, a thioredoxin-like domain, and corresponds to an arrested state of electron transfer. The catalytic core of VKOR is a four transmembrane helix bundle that surrounds a quinone, connected through an additional transmembrane segment with the periplasmic thioredoxin-like domain. We propose a pathway for how VKOR uses electrons from cysteines of newly synthesized proteins to reduce a quinone, a mechanism confirmed by in vitro reconstitution of vitamin K-dependent disulphide bridge formation. Our results have implications for the mechanism of the mammalian VKOR and explain how mutations can cause resistance to the VKOR inhibitor warfarin, the most commonly used oral anticoagulant.

  8. Aspects of Ribonucleotide Reductase Regulation and Genome Stability

    DEFF Research Database (Denmark)

    Nielsen, Helena Berner Nedergaard

    In all living cells, synthesis of the DNA building blocks, deoxyribonucleoside triphosphates (dNTPs), is tightly regulated to ensure a precise DNA replication to maintain genomic stability. Ribonucleotide reductase (RNR) is the enzyme responsible for reducing ribonucleotides to their deoxy forms....... RNR consists of two subunits: R1 and R2, both of which are essential. The activity of RNR is strictly regulated to control the dNTP pool, both by allosteric feedback control and transcriptional and translational controls. Four inhibitory proteins of RNR have been identified in yeast: Spd1 in fission...... yeast, and Sml1, Hug1, and Dif1 in budding yeast. An elevated, as well as a reduced dNTP pool is shown to lead to an increase in spontaneous mutation rates, hence regulation of RNR is very important in order to maintain genomic stability. No human inhibitory proteins have yet been identified to regulate...

  9. Two methylenetetrahydrofolate reductase gene (MTHFR) polymorphisms, schizophrenia and bipolar disorder

    DEFF Research Database (Denmark)

    Jönsson, Erik G; Larsson, Kristina; Vares, Maria;

    2008-01-01

    disorder. In a replication attempt the MTHFR C677T and A1298C SNPs were analyzed in three Scandinavian schizophrenia case-control samples. In addition, Norwegian patients with bipolar disorder were investigated. There were no statistically significant allele or genotype case-control differences. The...... present Scandinavian results do not verify previous associations between the putative functional MTHFR gene polymorphisms and schizophrenia or bipolar disorder. However, when combined with previous studies in meta-analyses there is still evidence for association between the MTHFR C677T polymorphism and......Recent meta-analyses of the methylenetetrahydrofolate reductase gene (MTHFR) have suggested association between two of its functional single gene polymorphisms (SNPs; C677T and A1298C) and schizophrenia. Studies have also suggested association between MTHFR C677T and A1298C variation and bipolar...

  10. Crystal structure of isoflavone reductase from alfalfa (Medicago sativa L.).

    Science.gov (United States)

    Wang, Xiaoqiang; He, Xianzhi; Lin, Jianqiao; Shao, Hui; Chang, Zhenzhan; Dixon, Richard A

    2006-05-19

    Isoflavonoids play important roles in plant defense and exhibit a range of mammalian health-promoting activities. Isoflavone reductase (IFR) specifically recognizes isoflavones and catalyzes a stereospecific NADPH-dependent reduction to (3R)-isoflavanone. The crystal structure of Medicago sativa IFR with deletion of residues 39-47 has been determined at 1.6A resolution. Structural analysis, molecular modeling and docking, and comparison with the structures of other NADPH-dependent enzymes, defined the putative binding sites for co-factor and substrate and potential key residues for enzyme activity and substrate specificity. Further mutagenesis has confirmed the role of Lys144 as a catalytic residue. This study provides a structural basis for understanding the enzymatic mechanism and substrate specificity of IFRs as well as the functions of IFR-like proteins. PMID:16600295

  11. Pulse radiolysis studies on superoxide reductase from Treponema pallidum

    CERN Document Server

    Nivière, V; Fontecave, M; Houée-Levin, C

    2015-01-01

    Superoxide reductases (SORs) are small metalloenzymes, which catalyze reduction of O2*- to H2O2. The reaction of the enzyme from Treponema pallidum with superoxide was studied by pulse radiolysis methods. The first step is an extremely fast bi-molecular reaction of the ferrous center with O2, with a rate constant of 6 x 10 (8) M(-1) s(-1). A first intermediate is formed which is converted to a second one with a slower rate constant of 4800 s(-1). This latter value is 10 times higher than the corresponding one previously reported in the case of SOR from Desulfoarculus baarsii. The reconstituted spectra for the two intermediates are consistent with formation of transient iron-peroxide species.

  12. Two methylenetetrahydrofolate reductase gene (MTHFR) polymorphisms, schizophrenia and bipolar disorder

    DEFF Research Database (Denmark)

    Jönsson, Erik G; Larsson, Kristina; Vares, Maria; Hansen, Thomas; Wang, August G; Djurovic, Srdjan; Rønningen, Kjersti S; Andreassen, Ole A; Agartz, Ingrid; Werge, Thomas; Terenius, Lars; Hall, Håkan

    disorder. In a replication attempt the MTHFR C677T and A1298C SNPs were analyzed in three Scandinavian schizophrenia case-control samples. In addition, Norwegian patients with bipolar disorder were investigated. There were no statistically significant allele or genotype case-control differences. The...... present Scandinavian results do not verify previous associations between the putative functional MTHFR gene polymorphisms and schizophrenia or bipolar disorder. However, when combined with previous studies in meta-analyses there is still evidence for association between the MTHFR C677T polymorphism and......Recent meta-analyses of the methylenetetrahydrofolate reductase gene (MTHFR) have suggested association between two of its functional single gene polymorphisms (SNPs; C677T and A1298C) and schizophrenia. Studies have also suggested association between MTHFR C677T and A1298C variation and bipolar...

  13. Middle East Respiratory Syndrome Coronavirus.

    Science.gov (United States)

    O'Keefe, Louise C

    2016-05-01

    Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is an emerging infectious disease that can present with flu-like symptoms. In individuals with comorbidities or who are immunosuppressed, it can be deadly. The disease is transmitted through contact with someone who has MERS-CoV. The occupational health nurse must be cognizant of and educate the workforce about MERS-CoV transmission, prevention, and treatment. PMID:26407596

  14. Stem cells and respiratory diseases

    OpenAIRE

    Soraia Carvalho Abreu; Tatiana Maron-Gutierrez; Cristiane Sousa Nascimento Baez Garcia; Marcelo Marcos Morales; Patricia Rieken Macedo Rocco

    2008-01-01

    Stem cells have a multitude of clinical implications in the lung. This article is a critical review that includes clinical and experimental studies of MedLine and SciElo database in the last 10 years, where we highlight the effects of stem cell therapy in acute respiratory distress syndrome or more chronic disorders such as lung fibrosis and emphysema. Although, many studies have shown the beneficial effects of stem cells in lung development, repair and remodeling; some important questions ne...

  15. Isolation and characterization of nitric oxide reductase from Paracoccus halodenitrificans.

    Science.gov (United States)

    Sakurai, N; Sakurai, T

    1997-11-11

    Nitric oxide reductase was isolated from the membrane fraction of a denitrifying bacterium, Paracoccus halodenitrificans, in the presence of n-dodecyl beta-D-maltoside. A relatively simple and effective procedure to purify NO reductase using DEAE-Toyopearl and hydroxyapatite (ceramic) chromatographies has been developed. The enzyme consisted of two subunits with molecular masses of 20 and 42 kDa associated with the c-type heme and two b-type hemes, respectively. The optical and magnetic circular dichroism (MCD) spectra of the oxidized (as isolated) and reduced enzymes indicated that the heme c is in the low-spin state and the hemes b are in the high- and low-spin states. The EPR spectrum also showed the presence of the split high-spin component (g perpendicular = 6.6, 6.0) and two low spin components (gz,y,x = 2.96, 2.26, 1.46, gz = 3.59). Although the presence of an extra iron was suggested from atomic absorption spectroscopy, a non-heme iron could not be detected by colorimetric titrations using ferene and 2-(5-nitro-2-pyridylazo)- 5-(N-propyl-N-sulfopropylamino)phenolate (PAPS). One of the extra signals at g = 4.3 and 2.00 might come from a non-heme iron, while they may originate from an adventitious iron and a certain nonmetallic radical, respectively. When CO acted on the reduced enzyme, both of the low-spin hemes were not affected, and when NO acted on the reduced enzyme, the optical and MCD spectra were of a mixture of the oxidized and reduced enzymes. Consequently, the reduction of NO was supposed to take place at the high-spin heme b. The heme c and the low-spin heme b centers were considered to function as electron mediators during the intermolecular and intramolecular processes. PMID:9374857

  16. Identification of imine reductase-specific sequence motifs.

    Science.gov (United States)

    Fademrecht, Silvia; Scheller, Philipp N; Nestl, Bettina M; Hauer, Bernhard; Pleiss, Jürgen

    2016-05-01

    Chiral amines are valuable building blocks for the production of a variety of pharmaceuticals, agrochemicals and other specialty chemicals. Only recently, imine reductases (IREDs) were discovered which catalyze the stereoselective reduction of imines to chiral amines. Although several IREDs were biochemically characterized in the last few years, knowledge of the reaction mechanism and the molecular basis of substrate specificity and stereoselectivity is limited. To gain further insights into the sequence-function relationships, the Imine Reductase Engineering Database (www.IRED.BioCatNet.de) was established and a systematic analysis of 530 putative IREDs was performed. A standard numbering scheme based on R-IRED-Sk was introduced to facilitate the identification and communication of structurally equivalent positions in different proteins. A conservation analysis revealed a highly conserved cofactor binding region and a predominantly hydrophobic substrate binding cleft. Two IRED-specific motifs were identified, the cofactor binding motif GLGxMGx5 [ATS]x4 Gx4 [VIL]WNR[TS]x2 [KR] and the active site motif Gx[DE]x[GDA]x[APS]x3 {K}x[ASL]x[LMVIAG]. Our results indicate a preference toward NADPH for all IREDs and explain why, despite their sequence similarity to β-hydroxyacid dehydrogenases (β-HADs), no conversion of β-hydroxyacids has been observed. Superfamily-specific conservations were investigated to explore the molecular basis of their stereopreference. Based on our analysis and previous experimental results on IRED mutants, an exclusive role of standard position 187 for stereoselectivity is excluded. Alternatively, two standard positions 139 and 194 were identified which are superfamily-specifically conserved and differ in R- and S-selective enzymes. Proteins 2016; 84:600-610. © 2016 Wiley Periodicals, Inc. PMID:26857686

  17. Fatty acyl-CoA reductases of birds

    Directory of Open Access Journals (Sweden)

    Hellenbrand Janine

    2011-12-01

    Full Text Available Abstract Background Birds clean and lubricate their feathers with waxes that are produced in the uropygial gland, a holocrine gland located on their back above the tail. The type and the composition of the secreted wax esters are dependent on the bird species, for instance the wax ester secretion of goose contains branched-chain fatty acids and unbranched fatty alcohols, whereas that of barn owl contains fatty acids and alcohols both of which are branched. Alcohol-forming fatty acyl-CoA reductases (FAR catalyze the reduction of activated acyl groups to fatty alcohols that can be esterified with acyl-CoA thioesters forming wax esters. Results cDNA sequences encoding fatty acyl-CoA reductases were cloned from the uropygial glands of barn owl (Tyto alba, domestic chicken (Gallus gallus domesticus and domestic goose (Anser anser domesticus. Heterologous expression in Saccharomyces cerevisiae showed that they encode membrane associated enzymes which catalyze a NADPH dependent reduction of acyl-CoA thioesters to fatty alcohols. By feeding studies of transgenic yeast cultures and in vitro enzyme assays with membrane fractions of transgenic yeast cells two groups of isozymes with different properties were identified, termed FAR1 and FAR2. The FAR1 group mainly synthesized 1-hexadecanol and accepted substrates in the range between 14 and 18 carbon atoms, whereas the FAR2 group preferred stearoyl-CoA and accepted substrates between 16 and 20 carbon atoms. Expression studies with tissues of domestic chicken indicated that FAR transcripts were not restricted to the uropygial gland. Conclusion The data of our study suggest that the identified and characterized avian FAR isozymes, FAR1 and FAR2, can be involved in wax ester biosynthesis and in other pathways like ether lipid synthesis.

  18. Evidence for a hexaheteromeric methylenetetrahydrofolate reductase in Moorella thermoacetica.

    Science.gov (United States)

    Mock, Johanna; Wang, Shuning; Huang, Haiyan; Kahnt, Jörg; Thauer, Rudolf K

    2014-09-01

    Moorella thermoacetica can grow with H₂ and CO₂, forming acetic acid from 2 CO₂ via the Wood-Ljungdahl pathway. All enzymes involved in this pathway have been characterized to date, except for methylenetetrahydrofolate reductase (MetF). We report here that the M. thermoacetica gene that putatively encodes this enzyme, metF, is part of a transcription unit also containing the genes hdrCBA, mvhD, and metV. MetF copurified with the other five proteins encoded in the unit in a hexaheteromeric complex with an apparent molecular mass in the 320-kDa range. The 40-fold-enriched preparation contained per mg protein 3.1 nmol flavin adenine dinucleotide (FAD), 3.4 nmol flavin mononucleotide (FMN), and 110 nmol iron, almost as predicted from the primary structure of the six subunits. It catalyzed the reduction of methylenetetrahydrofolate with reduced benzyl viologen but not with NAD(P)H in either the absence or presence of oxidized ferredoxin. It also catalyzed the reversible reduction of benzyl viologen with NADH (diaphorase activity). Heterologous expression of the metF gene in Escherichia coli revealed that the subunit MetF contains one FMN rather than FAD. MetF exhibited 70-fold-higher methylenetetrahydrofolate reductase activity with benzyl viologen when produced together with MetV, which in part shows sequence similarity to MetF. Heterologously produced HdrA contained 2 FADs and had NAD-specific diaphorase activity. Our results suggested that the physiological electron donor for methylenetetrahydrofolate reduction in M. thermoacetica is NADH and that the exergonic reduction of methylenetetrahydrofolate with NADH is coupled via flavin-based electron bifurcation with the endergonic reduction of an electron acceptor, whose identity remains unknown. PMID:25002540

  19. Supramolecular Organization of Respiratory Complexes.

    Science.gov (United States)

    Enríquez, José Antonio

    2016-01-01

    Since the discovery of the existence of superassemblies between mitochondrial respiratory complexes, such superassemblies have been the object of a passionate debate. It is accepted that respiratory supercomplexes are structures that occur in vivo, although which superstructures are naturally occurring and what could be their functional role remain open questions. The main difficulty is to make compatible the existence of superassemblies with the corpus of data that drove the field to abandon the early understanding of the physical arrangement of the mitochondrial respiratory chain as a compact physical entity (the solid model). This review provides a nonexhaustive overview of the evolution of our understanding of the structural organization of the electron transport chain from the original idea of a compact organization to a view of freely moving complexes connected by electron carriers. Today supercomplexes are viewed not as a revival of the old solid model but rather as a refined revision of the fluid model, which incorporates a new layer of structural and functional complexity. PMID:26734886

  20. Respiratory analysis system and method

    Science.gov (United States)

    Liu, F. F. (Inventor)

    1973-01-01

    A system is described for monitoring the respiratory process in which the gas flow rate and the frequency of respiration and expiration cycles can be determined on a real time basis. A face mask is provided with one-way inlet and outlet valves where the gas flow is through independent flowmeters and through a mass spectrometer. The opening and closing of a valve operates an electrical switch, and the combination of the two switches produces a low frequency electrical signal of the respiratory inhalation and exhalation cycles. During the time a switch is operated, the corresponsing flowmeter produces electric pulses representative of the flow rate; the electrical pulses being at a higher frequency than that of the breathing cycle and combined with the low frequency signal. The high frequency pulses are supplied to conventional analyzer computer which also receives temperature and pressure inputs and computes mass flow rate and totalized mass flow of gas. From the mass spectrometer, components of the gas are separately computed as to flow rate. The electrical switches cause operation of up-down inputs of a reversible counter. The respective up and down cycles can be individually monitored and combined for various respiratory measurements.

  1. Incidence of respiratory distress syndrome

    International Nuclear Information System (INIS)

    Objective: To determine the incidence of respiratory distress syndrome (RDS) in hospital born babies. Subjects and Methods: All live born infants delivered at the hospital and who fulfilled the diagnostic criteria of respiratory distress syndrome (RDS) were included in the study. Results: Ninety-four neonates developed RDS. Out of these, 88 (93.61%) were preterm and 06 (6.38%) were term infants. There was a male preponderance (65.95%). RDS was documented in 1.72% of total live births. 37.28% of preterm and 0.11% of term neonates born at the hospital. The incidence of RDS was 100% at 26 or less weeks of gestation, 57.14% at 32 weeks, and 3.70% at 36 weeks. The mortality with RDS was 41 (43.61%). Conclusion: RDS is the commonest cause of respiratory distress in the newborn, particularly, in preterm infants. It carries a high mortality rate and the incidence is more than that documented in the Western world. (author)

  2. Prognostic significance of ubiquinol-cytochrome c reductase hinge protein expression in patients with clear cell renal cell carcinoma

    Science.gov (United States)

    Liu, Wei-Si; Liu, Yi-Dong; Fu, Qiang; Zhang, Wei-Juan; Xu, Le; Chang, Yuan; Xu, Jie-Jie

    2016-01-01

    Ubiquinol-cytochrome c reductase hinge protein (UQCRH), as a connecter between cytochrome c1 with cytochrome c in complex III of respiratory chain, is top-ranked hypermethylated gene in clear cell renal cell carcinoma (ccRCC). This study aims to evaluate the impact of UQCRH on recurrence and survival of 424 ccRCC patients enrolled retrospectively from a single institution after surgical resection using immunohistochemistry method. UQCRH was specifically downregulated in ccRCC, compared with papillary and chromophobe RCC. Moreover, patients with low UQCRH were prone to possess high T stage and TNM stage and associated with poor survival and early recurrence. UQCRH remained an independent favorable prognosticator for OS (Hazard rate [HR]: 0.510, 95% CI: 0.328-0.795, p=0.003) and RFS (HR: 0.506, 95% CI: 0.334-0.767, p=0.001) adjusting with other well-established factors using backward Cox model. Furthermore, in stratified subgroups, patients with low UQCRH had an increased risk of recurrence (HR: 0.452, 95% CI: 0.261-0.783, p=0.005) and mortality (HR: 0.386, 95% CI: 0.205-0.726, p=0.003) in subgroup of early TNM stage. Taken together, UQCRH is a potential independent favorable prognostic factor for recurrence and survival of patients with ccRCC after nephrectomy.

  3. Nitrite and nitrous oxide reductase regulation by nitrogen oxides in Rhodobacter sphaeroides f. sp. denitrificans IL106.

    Science.gov (United States)

    Sabaty, M; Schwintner, C; Cahors, S; Richaud, P; Verméglio, A

    1999-10-01

    We have cloned the nap locus encoding the periplasmic nitrate reductase in Rhodobacter sphaeroides f. sp. denitrificans IL106. A mutant with this enzyme deleted is unable to grow under denitrifying conditions. Biochemical analysis of this mutant shows that in contrast to the wild-type strain, the level of synthesis of the nitrite and N(2)O reductases is not increased by the addition of nitrate. Growth under denitrifying conditions and induction of N oxide reductase synthesis are both restored by the presence of a plasmid containing the genes encoding the nitrate reductase. This demonstrates that R. sphaeroides f. sp. denitrificans IL106 does not possess an efficient membrane-bound nitrate reductase and that nitrate is not the direct inducer for the nitrite and N(2)O reductases in this species. In contrast, we show that nitrite induces the synthesis of the nitrate reductase. PMID:10498715

  4. The use of 5-alpha reductase inhibitors for the prevention of prostate cancer.

    Science.gov (United States)

    Yu, Eun-mi; El-Ayass, Walid; Aragon-Ching, Jeanny B

    2010-07-01

    The use of 5-alpha-reductase inhibitors has been studied not only in benign prostatic hyperplasia, but as a chemopreventive strategy in prostate cancer. Both finasteride and dutasteride, 5 alpha-reductase inhibitors (5ARI), have been shown to decrease the risk of prostate cancer. The results of the REDUCE trial using the dual alpha-reductase isoenzyme inhibitor dutasteride, has recently been published by Andriole et al. in the New England Journal of Medicine. Certain considerations regarding its use and applicability to men with high risk of developing prostate cancer are herein discussed. PMID:20574153

  5. Characterization and regulation of Leishmania major 3-hydroxy-3-methylglutaryl-CoA reductase

    DEFF Research Database (Denmark)

    Montalvetti, A; Pena Diaz, Javier; Hurtado, R;

    2000-01-01

    In eukaryotes the enzyme 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase catalyses the synthesis of mevalonic acid, a common precursor to all isoprenoid compounds. Here we report the isolation and overexpression of the gene coding for HMG-CoA reductase from Leishmania major. The protein from...... Leishmania lacks the membrane domain characteristic of eukaryotic cells but exhibits sequence similarity with eukaryotic reductases. Highly purified protein was achieved by ammonium sulphate precipitation followed by chromatography on hydroxyapatite. Kinetic parameters were determined for the protozoan...

  6. Virtual screening of plant derived compounds for aldose reductase inhibition using molecular docking.

    Science.gov (United States)

    Muppalaneni, Naresh Babu; Rao, Allam Appa

    2012-01-01

    The role of the aldose reductase in type 2 diabetes is widely described. Therefore, it is of interest to identify plant derived compounds to inhibit its activity. We studied the protein-ligand interaction of 267 compounds from different parts of seven plants (Allium sativum, Coriandrum sativum, Dacus carota, Murrayyakoneigii, Eucalyptus, Calendula officinalis and Lycopersicon esculentum) with aldose reductase as the target protein. Molecular docking and re-scoring of top ten compounds (using GOLD, AutoDock Vina, eHiTS, PatchDock and MEDock) followed by rank-sum technique identified compound allium38 with high binding affinity for aldose reductase. PMID:23275691

  7. Steroidal pyrazolines evaluated as aromatase and quinone reductase-2 inhibitors for chemoprevention of cancer.

    Science.gov (United States)

    Abdalla, Mohamed M; Al-Omar, Mohamed A; Bhat, Mashooq A; Amr, Abdel-Galil E; Al-Mohizea, Abdullah M

    2012-05-01

    The aromatase and quinone reductase-2 inhibition of synthesized heterocyclic pyrazole derivatives fused with steroidal structure for chemoprevention of cancer is reported herein. All compounds were interestingly less toxic than the reference drug (Cyproterone(®)). The aromatase inhibitory activities of these compounds were much more potent than the lead compound resveratrol, which has an IC(50) of 80 μM. In addition, all the compounds displayed potent quinone reductase-2 inhibition. Initially the acute toxicity of the compounds was assayed via the determination of their LD(50). The aromatase and quinone reductase-2 inhibitors resulting from this study have potential value in the treatment and prevention of cancer. PMID:22361454

  8. Effects of Freeze-thaw on Soil Characters and Arsenate Adsorption and Desorption%冻融周期对棕壤性质及砷吸附解吸特性的影响

    Institute of Scientific and Technical Information of China (English)

    孙跃嘉; 田甜; 何娜; 叶祝弘; 孙明慧; 杨丹

    2016-01-01

    Freeze-thawing is the common natural phenomena in northern China whichis the role of abiotic stress in soil. Freeze-thawing could influence the minerals, charge and organic material quantity, it also could influence the kind of charge and organic material form in soil. This study was based on brown soil test materials. Indoor experiment were employed to investigate the effects of arsenate adsorption and desorption ability in soils under different freeze-thawing treatments and its influencing factors. The results showed that the arsenate adsorption ability on soils could be well-described by the Langmuir equation.When the arsenic content in liquid balance was 15mg·kg-1, arsenic adsorption was tended to equilibrium state in soil. The amount of arsenate adsorption tened to increase with the the increasing of arsenate concentration. Compared with the no freeze-thaw treatments samples, arsenate adsorption capability of soils was significantly greater than unfreeze-thaw treatments samples. The amount of arsenate desorption of soils tended to decline when the amount of arsenate adsorption of soils were declined. The amount of arsenate desorption tened to increase with the the increasing of the amount of arsenate adsorption. Compared with the no freeze-thaw treatments samples, the amount of arsenate desorption of freeze-thaw treatments tened to increase with the rising cycles of freeze-thaw. The Arsenate maximum buffer capacity (MBC) of freeze-thaw soils closely related to pH, organic matter (OM), cation exchange capability (CEC), negative variable charge (CECv) and the degree reached 0.01 or 0.05 significance level. Meanwhile, the effects of CECv in freeze-thaw soils could be the main reason for the difference of soils arsenate adsorption and desorption under different freeze-thaw treatments. Explore the effects of arsenate adsorption and desorption ability in soils under different freeze-thawing treatments and its influencing factors could provide data reference and

  9. Regulation and function of versatile aerobic and anaerobic respiratory metabolism in Pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Hiroyuki eArai

    2011-05-01

    Full Text Available Pseudomonas aeruginosa is a ubiquitously distributed opportunistic pathogen that inhabits soil and water as well as animal-, human-, and plant-host-associated environments. The ubiquity would be attributed to its very versatile energy metabolism. P. aeruginosa has a highly branched respiratory chain terminated by multiple terminal oxidases and denitrification enzymes. Five terminal oxidases for aerobic respiration have been identified in the P. aeruginosa cells. Three of them, the cbb3-1 oxidase, the cbb3-2 oxidase, and the aa3 oxidase, are cytochrome c oxidases and the other two, the bo3 oxidase and the cyanide-insensitive oxidase, are quinol oxidases. Each oxidase has a specific affinity for oxygen, efficiency of energy coupling, and tolerance to various stresses such as cyanide and reactive nitrogen species. These terminal oxidases are used differentially according to the environmental conditions. P. aeruginosa also has a complete set of the denitrification enzymes that reduce nitrate to molecular nitrogen via nitrite, nitric oxide (NO, and nitrous oxide. These nitrogen oxides function as alternative electron acceptors and enable P. aeruginosa to grow under anaerobic conditions. One of the denitrification enzymes, NO reductase, is also expected to function for detoxification of NO produced by the host immune defense system. The control of the expression of these aerobic and anaerobic respiratory enzymes would contribute to the adaptation of P. aeruginosa to a wide range of environmental conditions including in the infected hosts. Characteristics of these respiratory enzymes and the regulatory system that controls the expression of the respiratory genes in the P. aeruginosa cells are overviewed in this article.

  10. Association between methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism and age of onset in schizophrenia

    DEFF Research Database (Denmark)

    Vares, Maria; Saetre, Peter; Deng, Hong;

    2010-01-01

    Different lines of evidence indicate that methylenetetrahydrofolate reductase (MTHFR) functional gene polymorphisms, causative in aberrant folate-homocysteine metabolism, are associated with increased vulnerability to several heritable developmental disorders. Opposing views are expressed...

  11. Histochemical Localization of Glutathione Dependent NBT—Reductase in Mouse Skin

    Institute of Scientific and Technical Information of China (English)

    YOESHWERSHUKLA

    2001-01-01

    Objective:Localization of the glutathione dependent Nitroblue tetrazolium(NBT) reductase in fresh frozen sections of mouse skin and possible dependence of NBT reductase on tissue thiol levels has been investigated.Methods:The fresh frozen tissue sections(8m thickness)were prepared and incuated in medium containing NBT,reduced glutathione(GSH) and Phosphate uffer,The staining for GSH was performed with mercury orange.Results:The activity of the NBT-reductase in mouse skin has een found to be localized in the areas rich in glutatione and actively proliferating area of the skin.Conclusion:The activity of the NBT-reductase seems to be dependent on the glutatione contents.

  12. Redesigning alcohol dehydrogenases/reductases for more efficient biosynthesis of enantiopure isomers.

    Science.gov (United States)

    Zhang, Rongzhen; Xu, Yan; Xiao, Rong

    2015-12-01

    Alcohol dehydrogenases/reductases predominantly catalyze the asymmetric biosynthesis of optically pure stereoisomers because of their unique chiral constitutions. The enantioselectivities of alcohol dehydrogenases/reductases are substrate- and cofactor-dependent, and therefore they usually catalyze specific reactions with high enantioselectivity under physiological conditions; this may not be suitable for asymmetric biosynthesis with non-natural substrates or non-natural cofactors, and under nonphysiological conditions. It is therefore necessary to modify alcohol dehydrogenases/reductases using various redesigning tools such as directed evolution and rational design, and their combinations, as well as engineering enzyme modules for more efficient production of "non-natural" products. In this article, progress in these aspects of alcohol dehydrogenase/reductase design is reviewed, and future challenges are discussed. PMID:26320091

  13. 5α-reductase inhibitors, antiviral and anti-tumor activities of some steroidal cyanopyridinone derivatives.

    Science.gov (United States)

    Al-Mohizea, Abdullah M; Al-Omar, Mohamed A; Abdalla, Mohamed M; Amr, Abdel-Galil E

    2012-01-01

    We herein report the 5α-reductase inhibitors, antiviral and anti-tumor activities of some synthesized heterocyclic cyanopyridone and cyanothiopyridone derivatives fused with steroidal structure. Initially the acute toxicity of the compounds was assayed via the determination of their LD(50). All the compounds, except 3b, were interestingly less toxic than the reference drug (Prednisolone(®)). Seventeen heterocyclic derivatives containing a cyanopyridone or cyanothiopyridone rings fused to a steroidal moiety were synthesized and screened for their 5α-reductase inhibitors, antiviral and anti-tumor activities comparable to that of Anastrozole, Bicalutamide, Efavirenz, Capravirine, Ribavirin, Oseltamivir and Amantadine as the reference drugs. Some of the compounds exhibited better 5α-reductase inhibitors, antiviral and anti-tumor activities than the reference drugs. The detailed 5α-reductase inhibitors, antiviral and anti-tumor activities of the synthesized compounds were reported. PMID:22057085

  14. Visual aided pacing in respiratory maneuvers

    Energy Technology Data Exchange (ETDEWEB)

    Rambaudi, L R [Laboratorio de Biofisica y Fisiologia ' Antonio Sadi Frumento' (Argentina); Rossi, E [Catedra de Bioingenieria II (Argentina); Mantaras, M C [Catedra de Bioingenieria II (Argentina); Perrone, M S [Laboratorio de Biofisica y Fisiologia ' Antonio Sadi Frumento' (Argentina); Siri, L Nicola [Catedra de Bioingenieria II (Argentina)

    2007-11-15

    A visual aid to pace self-controlled respiratory cycles in humans is presented. Respiratory manoeuvres need to be accomplished in several clinic and research procedures, among others, the studies on Heart Rate Variability. Free running respiration turns to be difficult to correlate with other physiologic variables. Because of this fact, voluntary self-control is asked from the individuals under study. Currently, an acoustic metronome is used to pace respiratory frequency, its main limitation being the impossibility to induce predetermined timing in the stages within the respiratory cycle. In the present work, visual driven self-control was provided, with separate timing for the four stages of a normal respiratory cycle. This visual metronome (ViMet) was based on a microcontroller which power-ON and -OFF an eight-LED bar, in a four-stage respiratory cycle time series handset by the operator. The precise timing is also exhibited on an alphanumeric display.

  15. Visual aided pacing in respiratory maneuvers

    International Nuclear Information System (INIS)

    A visual aid to pace self-controlled respiratory cycles in humans is presented. Respiratory manoeuvres need to be accomplished in several clinic and research procedures, among others, the studies on Heart Rate Variability. Free running respiration turns to be difficult to correlate with other physiologic variables. Because of this fact, voluntary self-control is asked from the individuals under study. Currently, an acoustic metronome is used to pace respiratory frequency, its main limitation being the impossibility to induce predetermined timing in the stages within the respiratory cycle. In the present work, visual driven self-control was provided, with separate timing for the four stages of a normal respiratory cycle. This visual metronome (ViMet) was based on a microcontroller which power-ON and -OFF an eight-LED bar, in a four-stage respiratory cycle time series handset by the operator. The precise timing is also exhibited on an alphanumeric display

  16. Respiratory Distress Syndrome and its Complications

    Directory of Open Access Journals (Sweden)

    Eren Kale Cekinmez

    2013-08-01

    Full Text Available Respiratory distress syndrome in premature babies is one of the most common and most important health problems in newborns. Respiratory distress syndrome of newborn is a syndrome in premature infants caused by developmental insufficiency of surfactant production and structural immaturity in the lungs. Respiratory distress syndrome begins shortly after birth and is manifest by tachypnea, tachycardia, chest wall retractions, expiratory grunting, nasal flaring and cyanosis during breathing efforts. Respiratory distress syndrome or complications caused by respiratory distress syndrome are the most important causes of mortality and morbidity in premature infants. This article briefly reviews respiratory distress syndrome and its complications. [Archives Medical Review Journal 2013; 22(4.000: 615-630

  17. Respiratory consequences of late preterm birth.

    Science.gov (United States)

    Pike, Katharine C; Lucas, Jane S A

    2015-06-01

    In developed countries most preterm births occur between 34 and 37 weeks' gestation. Deliveries during this 'late preterm' period are increasing and, since even mild prematurity is now recognised to be associated with adverse health outcomes, this presents healthcare challenges. Respiratory problems associated with late preterm birth include neonatal respiratory distress, severe RSV infection and childhood wheezing. Late preterm birth prematurely interrupts in utero lung development and is associated with maternal and early life factors which adversely affect the developing respiratory system. This review considers 1) mechanisms underlying the association between late preterm birth and impaired respiratory development, 2) respiratory morbidity associated with late preterm birth, particularly long-term outcomes, and 3) interventions which might protect respiratory development by addressing risk factors affecting the late preterm population, including maternal smoking, early life growth restriction and vulnerability to viral infection. PMID:25554628

  18. Comparison of the Stereospecificity and Immunoreactivity of NADH-Ferricyanide Reductases in Plant Membranes

    OpenAIRE

    Fredlund, Kenneth M.; Struglics, André; Widell, Susanne; ASKERLUND, Per; Kader, Jean-Claude; Møller, Ian M.

    1994-01-01

    The substrate stereospecificity of NADH-ferricyanide reductase activities in the inner mitochondrial membrane and peroxisomal membrane of potato (Solanum tuberosum L.) tubers, spinach (Spinacea oleracea L.) leaf plasma membrane, and red beetroot (Beta vulgaris L.) tonoplast were all specific for the [beta]-hydrogen of NADH, whereas the reductases in wheat root (Triticum aestivum L.) endoplasmic reticulum and potato tuber outer mitochondrial membrane were both [alpha]-hydrogen specific. In all...

  19. Nucleotide sequence of a cyanobacterial nifH gene coding for nitrogenase reductase

    OpenAIRE

    Mevarech, Moshe; Rice, Douglas; Haselkorn, Robert

    1980-01-01

    The nucleotide sequence of nifH, the structural gene for nitrogenase reductase (component II or Fe protein of nitrogenase) from the cyanobacterium Anabaena 7120 has been determined. Also reported are 194 bases of the 5′-flanking sequence and 170 bases of the 3′-flanking sequence. The predicted amino acid sequence was compared with that determined for the complete nitrogenase reductase of Clostridium pasteurianum and the cysteine-containing peptides of the protein from Azotobacter vinelandii. ...

  20. Overexpression of Soybean Isoflavone Reductase (GmIFR) Enhances Resistance to Phytophthora sojae in Soybean

    OpenAIRE

    Cheng, Qun; Li, Ninghui; Dong, Lidong; Zhang, Dayong; Fan, Sujie; Jiang, Liangyu; Wang, Xin; Xu, Pengfei; Zhang, Shuzhen

    2015-01-01

    Isoflavone reductase (IFR) is an enzyme involved in the biosynthetic pathway of isoflavonoid phytoalexin in plants. IFRs are unique to the plant kingdom and are considered to have crucial roles in plant response to various biotic and abiotic environmental stresses. Here, we report the characterization of a novel member of the soybean isoflavone reductase gene family GmIFR. Overexpression of GmIFR transgenic soybean exhibited enhanced resistance to Phytophthora sojae. Following stress treatmen...

  1. Design and synthesis of hepatoselective, pyrrole-based HMG-CoA reductase inhibitors.

    Science.gov (United States)

    Pfefferkorn, Jeffrey A; Song, Yuntao; Sun, Kuai-Lin; Miller, Steven R; Trivedi, Bharat K; Choi, Chulho; Sorenson, Roderick J; Bratton, Larry D; Unangst, Paul C; Larsen, Scott D; Poel, Toni-Jo; Cheng, Xue-Min; Lee, Chitase; Erasga, Noe; Auerbach, Bruce; Askew, Valerie; Dillon, Lisa; Hanselman, Jeffrey C; Lin, Zhiwu; Lu, Gina; Robertson, Andrew; Olsen, Karl; Mertz, Thomas; Sekerke, Catherine; Pavlovsky, Alexander; Harris, Melissa S; Bainbridge, Graeme; Caspers, Nicole; Chen, Huifen; Eberstadt, Matthias

    2007-08-15

    This manuscript describes the design and synthesis of a series of pyrrole-based inhibitors of HMG-CoA reductase for the treatment of hypercholesterolemia. Analogs were optimized using structure-based design and physical property considerations resulting in the identification of 44, a hepatoselective HMG-CoA reductase inhibitor with excellent acute and chronic efficacy in a pre-clinical animal models. PMID:17574412

  2. Protein Method for Investigating Mercuric Reductase Gene Expression in Aquatic Environments

    OpenAIRE

    Ogunseitan, O A

    1998-01-01

    A colorimetric assay for NADPH-dependent, mercuric ion-specific oxidoreductase activity was developed to facilitate the investigation of mercuric reductase gene expression in polluted aquatic ecosystems. Protein molecules extracted directly from unseeded freshwater and samples seeded with Pseudomonas aeruginosa PU21(Rip64) were quantitatively assayed for mercuric reductase activity in microtiter plates by stoichiometric coupling of mercuric ion reduction to a colorimetric redox chain through ...

  3. Molecular pharmacology and antitumor activity of palmarumycin based inhibitors of thioredoxin reductase.

    OpenAIRE

    Powis, Garth; Wipf, Peter; Lynch, Stephen M.; Birmingham, Anne; Kirkpatrick, D. Lynn

    2006-01-01

    The cytosolic thioredoxin (Trx) redox system comprising Trx-1 and the NADPH dependent thioredoxin reductase -1 reductase (TrxR-1) is an important regulator of cell growth and survival. Trx-1 is overexpressed in many human tumors where it is associated with increased cell proliferation, decreased apoptosis and decreased patient survival. We hypothesized that TrxR-1 provides a target to inhibit the activity of overexpressed Trx-1 for the development of novel anticancer agents. We found that the...

  4. Soil acidity as affecting micronutrients concentration, nitrato reductase enzyme activity and yield in upland rice plants

    OpenAIRE

    Edemar Moro; Carlos Alexandre Costa Crusciol; Heitor Cantarella; Adriano Stephan Nascente; Adriana Lima Moro; Fernando Broetto

    2013-01-01

    The lowest grain yield of rice under no-tillage system (NTS) in relation to the conventional system may be due to the predominance nitrate in the soil and the low nitrate reductase activity. Another reason may be caused by micronutrient deficiency because of superficially soil acidity corrections. Therefore, the objective of this study was to evaluate the changes caused by soil pH in the N forms in the soil, micronutrients concentration in rice plants, nitrate reductase activity, yield of ric...

  5. INHIBITORY ACTIVITY OF FLAVONOIDS ON THE LENS ALDOSE REDUCTASE OF HEALTHY AND DIABETIC RATS

    OpenAIRE

    M.T. Goodarzi; Zal, F; M. Malakooti; M. R. Safari S. Sadeghian

    2006-01-01

    Aldose reductase is a critical enzyme in the polyol pathway that plays an important role in diabetes mellitus. Inhibition of the activity of this enzyme can prevent cataract in diabetic patients’lenses. In this study the inhibitory effect of two flavonoids, quercetin and naringin, in the activity of aldose reductase in streptozotocin-induced diabetic and healthy rats were investigated. Thirty male rats were divided in six groups. The first, second and third group were healthy rats that receiv...

  6. Glutathione Reductase/Glutathione Is Responsible for Cytotoxic Elemental Sulfur Tolerance via Polysulfide Shuttle in Fungi*

    OpenAIRE

    Sato, Ikuo; Shimatani, Kanami; Fujita, Kensaku; Abe, Tsuyoshi; Shimizu, Motoyuki; Fujii, Tatsuya; Hoshino, Takayuki; Takaya, Naoki

    2011-01-01

    Fungi that can reduce elemental sulfur to sulfide are widely distributed, but the mechanism and physiological significance of the reaction have been poorly characterized. Here, we purified elemental sulfur-reductase (SR) and cloned its gene from the elemental sulfur-reducing fungus Fusarium oxysporum. We found that NADPH-glutathione reductase (GR) reduces elemental sulfur via glutathione as an intermediate. A loss-of-function mutant of the SR/GR gene generated less sulfide from elemental sulf...

  7. Expression of the mouse dihydrofolate reductase complementary deoxyribonucleic acid in simian virus 40 vectors.

    OpenAIRE

    Subramani, S.; Mulligan, R.; Berg, P

    1981-01-01

    A mouse complementary deoxyribonucleic acid segment coding for the enzyme dihydrofolate reductase has been cloned in two general classes of vectors containing simian virus 40 deoxyribonucleic acid: (i) those that can be propagated as virions in permissive cells and (ii) those that can be introduced into and maintained stably in various mammalian cells. Both types of vectors express the mouse dihydrofolate reductase by using signals supplied by simian virus 40 deoxyribonucleic acid sequences. ...

  8. Interaction of Product Analogs with the Active Site of Rhodobacter sphaeroides Dimethylsulfoxide Reductase

    OpenAIRE

    George, Graham N.; Nelson, Kimberly Johnson; Harris, Hugh H.; Doonan, Christian J.; Rajagopalan, K V

    2007-01-01

    We report a structural characterization using X-ray absorption spectroscopy of Rhodobacter sphaeroides dimethylsulfoxide (DMSO) reductase reduced with trimethylarsine, and show that this is structurally analogous to the physiologically relevant dimethylsulfide-reduced DMSO reductase. Our data unambiguously indicate that these species should be regarded as formal MoIV species, and indicate a classical coordination complex of trimethylarsine oxide, with no special structural distortions. The si...

  9. In Silico Docking studies of Aldose Reductase Inhibitory activity of selected Flavonoids

    OpenAIRE

    Muthuswamy Umamaheswari; C. S. Aji; Kuppusamy Asokkumar; Thirumalaisamy Sivashanmugam; Varadharajan Subhadradevi; Puliyath Jagannath; Arumugam Madeswaran

    2012-01-01

    New drugs for the inhibition of the enzyme aldose reductase are in development and they have to be screened before being considered for preclinical and clinical evaluation. The current study deals with the evaluation of the cyclooxygenase inhibitory activity of flavonoids using in silico docking studies. In this perspective, flavonoids like Farobin-A, Gericudranin- B, Glaziovianin-A, Rutin, and Xanthotoxin were selected. Epalrestat, a known aldose reductase inhibitor was used as the standard....

  10. Virtual screening of plant derived compounds for aldose reductase inhibition using molecular docking

    OpenAIRE

    Muppalaneni, Naresh Babu; Rao, Allam Appa

    2012-01-01

    The role of the aldose reductase in type 2 diabetes is widely described. Therefore, it is of interest to identify plant derived compounds to inhibit its activity. We studied the protein-ligand interaction of 267 compounds from different parts of seven plants (Allium sativum, Coriandrum sativum, Dacus carota, Murrayyakoneigii, Eucalyptus, Calendula officinalis and Lycopersicon esculentum) with aldose reductase as the target protein. Molecular docking and re-scoring of top ten compounds (using ...

  11. Respiratory Health among Cement Workers in Ethiopia

    OpenAIRE

    Zeleke, Zeyede K.

    2011-01-01

    Background: Little is known on dust exposure and respiratory health among cement cleaners. There are only a few follow-up studies on respiratory health among cement factory workers and also studies on acute effects of cement dust exposure are limited in numbers. Objective: This study aimed at assessing cement dust exposure and adverse respiratory health effects among Ethiopian cement production workers, with particular focus on cement cleaners. Method: The first paper was...

  12. Viral respiratory infections : Diagnosis and epidemiology

    OpenAIRE

    Rotzén Östlund, Maria

    2008-01-01

    Background. Respiratory viral infections are common causes of human morbidity and mortality in children as well as in adults. Adenovirus, influenza virus, parainfluenza virus and respiratory syncytial virus (RSV) have been recognized for many years. During recent years two main events have influenced both the diagnosis and our knowledge of respiratory virus epidemiology: (1) Five new viruses have been described; (2) the use of molecular methods for the diagnosis of respirato...

  13. Respiratory Microbiome of New-Born Infants

    OpenAIRE

    Gallacher, David J.; Kotecha, Sailesh

    2016-01-01

    The respiratory tract, once believed to be sterile, harbors diverse bacterial communities. The role of microorganisms within health and disease is slowly being unraveled. Evidence points to the neonatal period as a critical time for establishing stable bacterial communities and influencing immune responses important for long-term respiratory health. This review summarizes the evidence of early airway and lung bacterial colonization and the role the microbiome has on respiratory health in the ...

  14. Small animal disease surveillance: respiratory disease

    OpenAIRE

    Sánchez-Vizcaíno, Fernando; Daly, Janet M.; Philip H Jones; Dawson, Susan; Gaskell, Rosalind; Menacere, Tarek; Heayns, Bethaney; Wardeh, Maya; Newman, Jenny; Everitt, Sally; Day, Michael J.; McConnell, Katie; Noble, Peter J.M.; Radford, Alan D

    2016-01-01

    This second Small Animal Disease Surveillance report focuses on syndromic surveillance of i) respiratory disease in veterinary practice and ii) feline calicivirus (FCV) based on laboratory diagnosis, in a large veterinary-visiting pet population of the UK between January 2014 and December 2015. Presentation for respiratory disease comprised 1.7%, 2.3% and 2.5% of canine, feline and rabbit consultations, respectively. In dogs, the most frequent respiratory sign reported was coughing (71.1% of ...

  15. Respiratory system involvement in Costello syndrome.

    Science.gov (United States)

    Gomez-Ospina, Natalia; Kuo, Christin; Ananth, Amitha Lakshmi; Myers, Angela; Brennan, Marie-Luise; Stevenson, David A; Bernstein, Jonathan A; Hudgins, Louanne

    2016-07-01

    Costello syndrome (CS) is a multisystem disorder caused by heterozygous germline mutations in the HRAS proto-oncogene. Respiratory system complications have been reported in individuals with CS, but a comprehensive description of the full spectrum and incidence of respiratory symptoms in these patients is not available. Here, we report the clinical course of four CS patients with respiratory complications as a major cause of morbidity. Review of the literature identified 56 CS patients with descriptions of their neonatal course and 17 patients in childhood/adulthood. We found that in the neonatal period, respiratory complications are seen in approximately 78% of patients with transient respiratory distress reported in 45% of neonates. Other more specific respiratory diagnoses were reported in 62% of patients, the majority of which comprised disorders of the upper and lower respiratory tract. Symptoms of upper airway obstruction were reported in CS neonates but were more commonly diagnosed in childhood/adulthood (71%). Analysis of HRAS mutations and their respiratory phenotype revealed that the common p.Gly12Ser mutation is more often associated with transient respiratory distress and other respiratory diagnoses. Respiratory failure and dependence on mechanical ventilation occurs almost exclusively with rare mutations. In cases of prenatally diagnosed CS, the high incidence of respiratory complications in the neonatal period should prompt anticipatory guidance and development of a postnatal management plan. This may be important in cases involving rarer mutations. Furthermore, the high frequency of airway obstruction in CS patients suggests that otorhinolaryngological evaluation and sleep studies should be considered. © 2016 Wiley Periodicals, Inc. PMID:27102959

  16. Pathophysiology and Classification of Respiratory Failure.

    Science.gov (United States)

    Lamba, Tejpreet Singh; Sharara, Rihab Saeed; Singh, Anil C; Balaan, Marvin

    2016-01-01

    Respiratory failure is a condition in which the respiratory system fails in one or both of its gas exchange functions. It is a major cause of morbidity and mortality in patients admitted to intensive care units. It is a result of either lung failure, resulting in hypoxemia, or pump failure, resulting in alveolar hypoventilation and hypercapnia. This article covers the basic lung anatomy, pathophysiology, and classification of respiratory failure. PMID:26919670

  17. Central Neurogenic Respiratory Failure: A Challenging Diagnosis

    OpenAIRE

    Carvalho, Flávio A.; Bernardino, Tenille; Maciel, Ricardo O.H.; Felizola, Sérgio F.A.; Costa, Eduardo L.V.; Silva, Gisele S

    2011-01-01

    Background Central nervous system lesions are rare causes of respiratory failure. Simple observation of the breathing pattern can help localize the lesion, but the examiner needs to be aware of potential pitfalls such as metabolic or pulmonary alterations. Methods We describe 3 cases in which central neurogenic respiratory failure occurred simultaneously with other alterations or in an unusual presentation. Results All patients were diagnosed with central neurogenic respiratory failure and tr...

  18. The respiratory neuromuscular system in Pompe disease☆

    OpenAIRE

    Fuller, David D.; Mai K. ElMallah; Barbara K Smith; Corti, Manuela; Lawson, Lee Ann; Falk, Darin J.; Byrne, Barry J

    2013-01-01

    Pompe disease is due to mutations in the gene encoding the lysosomal enzyme acid α-glucosidase (GAA). Absence of functional GAA typically results in cardiorespiratory failure in the first year; reduced GAA activity is associated with progressive respiratory failure later in life. While skeletal muscle pathology contributes to respiratory insufficiency in Pompe disease, emerging evidence indicates that respiratory neuron dysfunction is also a significant part of dysfunction in motor units. Ani...

  19. Respiratory Distress Syndrome and its Complications

    OpenAIRE

    Eren Kale Cekinmez; Hacer Yapicioglu Yildizdas; Ferda Ozlu

    2013-01-01

    Respiratory distress syndrome in premature babies is one of the most common and most important health problems in newborns. Respiratory distress syndrome of newborn is a syndrome in premature infants caused by developmental insufficiency of surfactant production and structural immaturity in the lungs. Respiratory distress syndrome begins shortly after birth and is manifest by tachypnea, tachycardia, chest wall retractions, expiratory grunting, nasal flaring and cyanosis during breathing effor...

  20. Respiratory Dysfunction in Chronic Neck Pain

    OpenAIRE

    Dimitriadis, Zacharias

    2011-01-01

    Background: Patients with chronic neck pain have a number of factors that could constitute a predisposition for respiratory dysfunction. However, the existing evidence is limited and not well established, and many questions such as the association of neck pain deficits with respiratory function remain unanswered. Thus, the aim of this study was to investigate whether patients with chronic neck have accompanying respiratory dysfunction and which are the neck pain deficits which principally pre...

  1. Live-Attenuated Respiratory Syncytial Virus Vaccines

    OpenAIRE

    Karron, Ruth A.; Buchholz, Ursula J.; Collins, Peter L.

    2013-01-01

    Live-attenuated respiratory syncytial virus (RSV) vaccines offer several advantages for immunization of infants and young children: (1) they do not cause vaccine-associated enhanced RSV disease; (2) they broadly stimulate innate, humoral, and cellular immunity, both systemically and locally in the respiratory tract; (3) they are delivered intranasally; and (4) they replicate in the upper respiratory tract of young infants despite the presence of passively acquired maternally derived RSV neutr...

  2. Henipavirus Pathogenesis in Human Respiratory Epithelial Cells

    OpenAIRE

    Escaffre, Olivier; Borisevich, Viktoriya; Carmical, J. Russ; Prusak, Deborah; Prescott, Joseph; Feldmann, Heinz; Rockx, Barry

    2013-01-01

    Hendra virus (HeV) and Nipah virus (NiV) are deadly zoonotic viruses for which no vaccines or therapeutics are licensed for human use. Henipavirus infection causes severe respiratory illness and encephalitis. Although the exact route of transmission in human is unknown, epidemiological studies and in vivo studies suggest that the respiratory tract is important for virus replication. However, the target cells in the respiratory tract are unknown, as are the mechanisms by which henipaviruses ca...

  3. The role of glutathione reductase and related enzymes on cellular redox homoeostasis network.

    Science.gov (United States)

    Couto, Narciso; Wood, Jennifer; Barber, Jill

    2016-06-01

    In this review article we examine the role of glutathione reductase in the regulation, modulation and maintenance of cellular redox homoeostasis. Glutathione reductase is responsible for maintaining the supply of reduced glutathione; one of the most abundant reducing thiols in the majority of cells. In its reduced form, glutathione plays key roles in the cellular control of reactive oxygen species. Reactive oxygen species act as intracellular and extracellular signalling molecules and complex cross talk between levels of reactive oxygen species, levels of oxidised and reduced glutathione and other thiols, and antioxidant enzymes such as glutathione reductase determine the most suitable conditions for redox control within a cell or for activation of programmed cell death. Additionally, we discuss the translation and expression of glutathione reductase in a number of organisms including yeast and humans. In yeast and human cells, a single gene expresses more than one form of glutathione reductase, destined for residence in the cytoplasm or for translocation to different organelles; in plants, however, two genes encoding this protein have been described. In general, insects and kinetoplastids (a group of protozoa, including Plasmodia and Trypanosoma) do not express glutathione reductase or glutathione biosynthetic enzymes. Instead, they express either the thioredoxin system or the trypanothione system. The thioredoxin system is also present in organisms that have the glutathione system and there may be overlapping functions with cross-talk between the two systems. Finally we evaluate therapeutic targets to overcome oxidative stress associated cellular disorders. PMID:26923386

  4. INHIBITION OF TYPE I 5α-REDUCTASE BY MEDICINAL PLANT EXTRACTS

    Directory of Open Access Journals (Sweden)

    Patil Vijaya

    2011-03-01

    Full Text Available Type I 5α-reductase has been implicated in skin disorders such as acne, hirsutism and male pattern baldness and its inhibition offers a potential treatment for these disorders. The aim of this study was to investigate the inhibition of type I 5α-reductase activity by extracts from Indian medicinal plants. Plant extracts were screened and selected based on their ability to inhibit Propionibacterium acnes and Staphylococcus epidermidis. Since type I 5α-reductase metabolises testosterone to Δ4-androstene-3, 17-dione, the activity of enzyme was determined using RIA for testosterone and Δ4-androstene-3, 17-dione. It was found that methanolic extract of Embelia ribes was a potent inhibitor of type I 5α-reductase (IC50:100μg/mL. Extracts of Vitex negundo, Terminalia chebula, and Terminalia bellerica which also inhibited type I 5α-reductase (IC50: 200-390 μg /mL. Therefore herbal formulation of these plant extracts may be used in the treatment of skin disorders involving type I 5α-reductase.

  5. Nitrate reductase activity and its relationship with applied nitrogen in soybean

    International Nuclear Information System (INIS)

    Field experiments were conducted to study the nitrate reductase activity and its relationship to nitrogen by using frame tests (pot without bottom), sand culture and 15N-urea at transplanting in soybean variety Suinong 14. Results showed that the activity of nitrate reductase in leaf changed as a signal peak curve with the soybean growth, lower in vegetative growth phase, higher in reproductive growth period and reached the peak in blooming period, then decreased gradually. Nitrogen application showed obvious effect on the nitrate reductase activity. The activities of nitrate reductase in leaves followed the order of N135 > N90 > N45 > N0 in vegetative growth stage, no clear regularity was found during the whole reproductive growth period. The activities of nitrate reductase in leaves were accorded with the order of upper leaves > mid leaves > lower leaves, and it was very significant differences (P15N labeling method during beginning seed stage and full seed stage shown that 15N abundance in various organs at different node position also followed the same order, suggesting that high level of nitrate reductase activity at upper leaves of soybean promoted the assimilation of NO3-. (authors)

  6. Isobutyraldehyde production from Escherichia coli by removing aldehyde reductase activity

    Directory of Open Access Journals (Sweden)

    Rodriguez Gabriel M

    2012-06-01

    Full Text Available Abstract Background Increasing global demand and reliance on petroleum-derived chemicals will necessitate alternative sources for chemical feedstocks. Currently, 99% of chemical feedstocks are derived from petroleum and natural gas. Renewable methods for producing important chemical feedstocks largely remain unaddressed. Synthetic biology enables the renewable production of various chemicals from microorganisms by constructing unique metabolic pathways. Here, we engineer Escherichia coli for the production of isobutyraldehyde, which can be readily converted to various hydrocarbons currently derived from petroleum such as isobutyric acid, acetal, oxime and imine using existing chemical catalysis. Isobutyraldehyde can be readily stripped from cultures during production, which reduces toxic effects of isobutyraldehyde. Results We adopted the isobutanol pathway previously constructed in E. coli, neglecting the last step in the pathway where isobutyraldehyde is converted to isobutanol. However, this strain still overwhelmingly produced isobutanol (1.5 g/L/OD600 (isobutanol vs 0.14 g/L/OD600 (isobutyraldehyde. Next, we deleted yqhD which encodes a broad-substrate range aldehyde reductase known to be active toward isobutyraldehyde. This strain produced isobutanol and isobutyraldehyde at a near 1:1 ratio, indicating further native isobutyraldehyde reductase (IBR activity in E. coli. To further eliminate isobutanol formation, we set out to identify and remove the remaining IBRs from the E. coli genome. We identified 7 annotated genes coding for IBRs that could be active toward isobutyraldehyde: adhP, eutG, yiaY, yjgB, betA, fucO, eutE. Individual deletions of the genes yielded only marginal improvements. Therefore, we sequentially deleted all seven of the genes and assessed production. The combined deletions greatly increased isobutyraldehyde production (1.5 g/L/OD600 and decreased isobutanol production (0.4 g/L/OD600. By assessing production by

  7. Teor de arsênio e adsorção competitiva arsênio/fosfato e arsênio/sulfato em solos de Minas Gerais, Brasil Arsenate content, and arsenate/phosphate and arsenate/sulphate competitive adsorption in soils from Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    Mari Lucia Campos

    2013-06-01

    Full Text Available A alta toxicidade de As para homens e animais gera a necessidade de estudos do comportamento químico do arsenato nos solos que possam auxiliar na mitigação de áreas contaminadas com arsênio. Este trabalho teve por objetivo avaliar o teor total e a adsorção de As na ausência e presença dos ânions fosfato e sulfato em seis diferentes classes de solos do estado de Minas Gerais, Brasil. Os solos alvo deste estudo são: o Neossolo Flúvico (RU, Gleissolo Háplico (GX, Gleissolo Melânico (GM, Latossolo Vermelho Distrófico (LVd, coletados em Lavras; Neossolo Quartzarênico (RQ, coletado em Itutinga e o Latossolo Amarelo Distrófico (LAd, coletado em Rosário, no estado de Minas Gerais. As amostras de solo foram secas, moídas e peneiradas em peneira de 2,0mm para execução do teste de adsorção e peneiradas em peneira plástica com malha de 1,5mm para determinação do teor de As, o qual foi determinado pelo método 3051A. A adsorção de As foi avaliada na dose de1500µmol L-1 de As, 1500µmol L-1 de As + 1500µmol L-1 de P e 1500µmol L-1 de As + 750µmolL-1 de S, em relação solo:solução final de 1:100, a pH 5,5 e força iônica de 15mmol L-1. Os seis solos apresentaram teor médio de As entre 0,14 e 9,3mgkg-1. A porcentagem adsorvida de arsênio na ausência dos outros ânions seguiu a sequência GM>LVd=RU=LAd=GX=RQ. A adição de fosfato e sulfato reduziu a porcentagem de arsênio adsorvido e, por consequência, houve um aumentou na concentração de arsênio disponível na solução do solo.The high toxicity of arsenic to humans and animals creates the need to study the chemical behavior of arsenate in soils that can help in the mitigation of areas contaminated with arsenic. This work aimed to evaluate the total content and adsorption in the absence and presence of phosphate and sulfate anions in six different soil classes in the state of Minas Gerais, Brazil. Soils aim of this study are: Fluvic Neosol (RU, Haplic Gleysol (GX

  8. Coal Mining-Related Respiratory Diseases

    Science.gov (United States)

    ... ray Surveillance Program (CWXSP) Frequently Asked Questions Coal Miner Health Surveillance Coal Mining-Related Respiratory Diseases CWHSP Data Query System CWHSP Public Data Digital Imaging Activity ...

  9. Bovine respiratory syncytial virus (BRSV): A review

    DEFF Research Database (Denmark)

    Larsen, Lars Erik

    2000-01-01

    Bovine respiratory syncytial virus (BRSV) infection is the major cause of respiratory disease in calves during the first year of life. The study of the virus has been difficult because of its lability and very poor growth in cell culture. However, during the last decade, the introduction of new...... complex and unpredictable which makes the diagnosis and subsequent therapy very difficult. BRSV is closely related to human respiratory syncytial virus (HRSV) which is an important cause of respiratory disease in young children. In contrast to BRSV, the recent knowledge of HRSV is regularly extensively...

  10. Occurrence and phylogenetic analysis of bovine respiratory syncytial virus in outbreaks of respiratory disease in Norway

    OpenAIRE

    Klem, Thea; Rimstad, Espen; Stokstad, Maria

    2014-01-01

    Background Bovine respiratory syncytial virus (BRSV) is one of the major pathogens involved in the bovine respiratory disease (BRD) complex. The seroprevalence to BRSV in Norwegian cattle herds is high, but its role in epidemics of respiratory disease is unclear. The aims of the study were to investigate the etiological role of BRSV and other respiratory viruses in epidemics of BRD and to perform phylogenetic analysis of Norwegian BRSV strains. Results BRSV infection was detected either serol...

  11. The effect of anxiety on respiratory sensory gating measured by respiratory-related evoked potentials

    OpenAIRE

    Chan, Pei-Ying S.; von Leupoldt, Andreas; Bradley, Margaret M.; Lang, Peter J.; Davenport, Paul W.

    2012-01-01

    Respiratory sensory gating is evidenced by decreased amplitudes of the respiratory-related evoked poten-Received 24 September 2011 tials (RREP) N1 peak for the second (S2) compared to the first occlusion (S1) when two paired occlusions Accepted 2 July 2012 are presented with a 500-millisecond (ms) inter-stimulus-interval during one inspiration. Because anxiety is prevalent in respiratory diseases and associated with altered respiratory perception, we tested whether anxiety can modulate indivi...

  12. Characterization of two alkyl hydroperoxide reductase C homologs alkyl hydroperoxide reductase C_H1 and alkyl hydroperoxide reductase C_H2 in Bacillus subtilis

    Institute of Scientific and Technical Information of China (English)

    Mee-Kyung; Cha; Yoo-Jeen; Bae; Kyu-Jeong; Kim; Byung-Joon; Park; Il-Han; Kim

    2015-01-01

    AIM: To identify alkyl hydroperoxide reductase subunit C(AhpC) homologs in Bacillus subtilis(B. subtilis) and to characterize their structural and biochemical properties. AhpC is responsible for the detoxification of reactive oxygen species in bacteria.METHODS: Two AhpC homologs(AhpC_H1 and AhpC_H2) were identified by searching the B. subtilis database; these were then cloned and expressed in Escherichia coli. AhpC mutants carrying substitutions of catalytically important Cys residues(C37S, C47 S, C166 S, C37/47 S, C37/166 S, C47/166 S, and C37/47/166 S for AhpC_H1; C52 S, C169 S, and C52/169 S for AhpC_H2) were obtained by site-directed mutagenesis and purified, and their structure-function relationship was analyzed. The B. subtilis ahp C genes were disrupted by the short flanking homology method, and the phenotypes of the resulting AhpC-deficient bacteria were examined.RESULTS: Comparative characterization of AhpC homologs indicates that AhpC_H1 contains an extra C37, which forms a disulfide bond with the peroxidatic C47, and behaves like an atypical 2-Cys AhpC, while AhpC_H2 functions like a typical 2-Cys AhpC. Tryptic digestion analysis demonstrated the presence of intramolecular Cys37-Cys47 linkage, which could be reduced by thioredoxin, resulting in the association of the dimer into higher-molecular-mass complexes. Peroxidase activity analysis of Cys→Ser mutants indicated that three Cys residues were involved in the catalysis. AhpC_H1 was resistant to inactivation by peroxide substrates, but had lower activity at physiological H2O2 concentrations compared to AhpC_H2, suggesting that in B. subtilis, the enzymes may be physiologically functional at different substrate concentrations. The exposure to organic peroxides induced AhpC_H1 expression, while AhpC_H1-deficient mutants exhibited growth retardation in the stationary phase, suggesting the role of AhpC_H1 as an antioxidant scavenger of lipid hydroperoxides and a stress-response factor in B. subtilis

  13. [Phytotherapy of respiratory tract diseases].

    Science.gov (United States)

    Bylka, Wiesława; Witkowska-Banaszczak, Ewa; Studzińska-Sroka, Elzbieta; Matławska, Irena

    2012-01-01

    Herbal medicines have been used in cough due to their antitussive and expectorant activity. Antitussives act either centrally on the cough center of the brain or peripherally on the cough receptors in the respiratory passages. The antitussive effect of many herbs results from the content of mucilage, which exerts protective and demulcent activity. The activity of expectorant herbs results primarily from their influence on the gastric mucose (saponins and ipec alkaloids). This proves reflex stimulation which leads to an increase in the secretion of bronchial glands. Volatile-oil type expectorant herbs exert a direct stimulatory effect on the bronchial glands by means of local irritation with antibacterial activity. In colds and flu, herbs containing volatile oil can be used; also, volatile oils are ingredients of syrups and liquids as well as external phytomedicines in the form of liniments, ointments, and inhalations. The paper shows the herbs and phytomedicines present on the Polish market used for the treatment of respiratory tract diseases. PMID:23289257

  14. Binding of Natural and Synthetic Polyphenols to Human Dihydrofolate Reductase

    Directory of Open Access Journals (Sweden)

    José Neptuno Rodríguez-López

    2009-12-01

    Full Text Available Dihydrofolate reductase (DHFR is the subject of intensive investigation since it appears to be the primary target enzyme for antifolate drugs. Fluorescence quenching experiments show that the ester bond-containing tea polyphenols (--epigallocatechin gallate (EGCG and (--epicatechin gallate (ECG are potent inhibitors of DHFR with dissociation constants (KD of 0.9 and 1.8 μM, respectively, while polyphenols lacking the ester bound gallate moiety [e.g., (--epigallocatechin (EGC and (--epicatechin (EC] did not bind to this enzyme. To avoid stability and bioavailability problems associated with tea catechins we synthesized a methylated derivative of ECG (3-O-(3,4,5-trimethoxybenzoyl-(--epicatechin; TMECG, which effectively binds to DHFR (KD = 2.1 μM. In alkaline solution, TMECG generates a stable quinone methide product that strongly binds to the enzyme with a KD of 8.2 nM. Quercetin glucuronides also bind to DHFR but its effective binding was highly dependent of the sugar residue, with quercetin-3-xyloside being the stronger inhibitor of the enzyme with a KD of 0.6 μM. The finding that natural polyphenols are good inhibitors of human DHFR could explain the epidemiological data on their prophylactic effects for certain forms of cancer and open a possibility for the use of natural and synthetic polyphenols in cancer chemotherapy.

  15. Rapid identification of aldose reductase inhibitory compounds from Perilla frutescens.

    Science.gov (United States)

    Paek, Ji Hun; Shin, Kuk Hyun; Kang, Young-Hee; Lee, Jae-Yong; Lim, Soon Sung

    2013-01-01

    The ethyl acetate (EtOAc) soluble fraction of methanol extracts of Perilla frutescens (P. frutescens) inhibits aldose reductase (AR), the key enzyme in the polyol pathway. Our investigation of inhibitory compounds from the EtOAc soluble fraction of P. frutescens was followed by identification of the inhibitory compounds by a combination of HPLC microfractionation and a 96-well enzyme assay. This allowed the biological activities to be efficiently matched with selected HPLC peaks. Structural analyses of the active compounds were performed by LC-MS(n). The main AR inhibiting compounds were tentatively identified as chlorogenic acid and rosmarinic acid by LC-MS(n). A two-step high speed counter current chromatography (HSCCC) isolation method was developed with a solvent system of n-hexane-ethyl acetate-methanol-water at 1.5:5:1:5, v/v and 3:7:5:5, v/v. The chemical structures of the isolated compounds were determined by (1)H- and (13)C-nuclear magnetic resonance spectrometry (NMR). The main compounds inhibiting AR in the EtOAc fraction of methanol extracts of P. frutescens were identified as chlorogenic acid (2) (IC50 = 3.16 μ M), rosmarinic acid (4) (IC50 = 2.77 μ M), luteolin (5) (IC50 = 6.34 μ M), and methyl rosmarinic acid (6) (IC50 = 4.03 μ M). PMID:24308003

  16. Expression analysis of dihydroflavonol 4-reductase genes in Petunia hybrida.

    Science.gov (United States)

    Chu, Y X; Chen, H R; Wu, A Z; Cai, R; Pan, J S

    2015-01-01

    Dihydroflavonol 4-reductase (DFR) genes from Rosa chinensis (Asn type) and Calibrachoa hybrida (Asp type), driven by a CaMV 35S promoter, were integrated into the petunia (Petunia hybrida) cultivar 9702. Exogenous DFR gene expression characteristics were similar to flower-color changes, and effects on anthocyanin concentration were observed in both types of DFR gene transformants. Expression analysis showed that exogenous DFR genes were expressed in all of the tissues, but the expression levels were significantly different. However, both of them exhibited a high expression level in petals that were starting to open. The introgression of DFR genes may significantly change DFR enzyme activity. Anthocyanin ultra-performance liquid chromatography results showed that anthocyanin concentrations changed according to DFR enzyme activity. Therefore, the change in flower color was probably the result of a DFR enzyme change. Pelargonidin 3-O-glucoside was found in two different transgenic petunias, indicating that both CaDFR and RoDFR could catalyze dihydrokaempferol. Our results also suggest that transgenic petunias with DFR gene of Asp type could biosynthesize pelargonidin 3-O-glucoside. PMID:25966276

  17. 5alpha-reductase: history and clinical importance.

    Science.gov (United States)

    Marks, Leonard S

    2004-01-01

    The treatment of men with symptomatic benign prostatic hyperplasia (BPH) has shifted dramatically from surgery to drug therapy over the past decade. The revolution in BPH treatment began with the discovery of congenital 5alpha-reductase (5AR) deficiency, leading to the appreciation of 2 different androgenic hormones: testosterone, which mediates overt masculinization in the adult male, and dihydrotestosterone (DHT), which mediates prostatic growth, acne, facial beard, and male pattern baldness. Inhibition of DHT in adults results in prostatic shrinkage and symptomatic relief in many men, without the side effects seen with conventional androgen-deprivation therapy. The 5AR inhibitor drugs (finasteride and the dual inhibitor, dutasteride) are able to ablate the accumulation of intraprostatic DHT, the mechanism most responsible for prostate growth and maintenance. Not only may these drugs relieve symptoms, but they may also alter the natural history of the BPH process. Future indications for the 5ARI drugs could include chemoprevention of prostate cancer, prophylaxis of BPH-related complications, and treatment of BPH-associated hematuria. PMID:16985920

  18. Regulation and degradation of HMGCo-A reductase.

    Science.gov (United States)

    Panda, T; Devi, V Amutha

    2004-12-01

    The enzyme, 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) controls the biosynthesis of cholesterol. Hypercholesterolemia and atherosclerosis are critical health risk factors. One way of controlling these risk factors is to manipulate regulation as well as degradation of HMGR. At present, a class of compounds called statins, which are HMGR inhibitors, are used for the treatment of hypercholesterolemia. However, statins suffer major setbacks as their use produces more adverse reactions than the desirable one of inhibiting the enzyme. Genetically engineered forms of HMGR are also studied in primitive life forms like bacteria, but detailed investigation of this enzyme in human systems is certainly required. Extensive studies have been made on the regulatory aspects of this enzyme, but no breakthrough is conspicuous in the clinical background to find an alternative treatment for hypercholesterolemia. The immediate need is to find an alternate way of regulating degradation of the enzyme. This review presents the importance of regulation and degradation of the HMGR enzyme in different systems to gain possible insight into alternative schemes for regulating this enzyme and, if these exist, the feasibility of extending them same to studies in mammalian systems. A high degree of similarity exists between mammalian and yeast HMGR. Detailed studies reported on the regulation and degradation of the yeast enzyme also throw more light on the mammalian system, leading to a better understanding of ways of controlling hypercholesterolemia. PMID:15558272

  19. Methylenetetrahydrofolate Reductase Genotypes, Dietary Habits and Susceptibility to Stomach Cancer

    Institute of Scientific and Technical Information of China (English)

    ChangmingGao; TakezakiToshiro; JianzhongWu; JianhuoDing; YantingLiu; SupingLi; PingSu; XuHu; TianliongXu; HamajimaNobuyuki; TajimaKazuo

    2004-01-01

    OBJECTIVE To study the relation among methylenetetrahydrofolate reductase (MTHFR) C677T genotypes, dietary habits and the risk of stomach cancer (SC).METHODS A case-control study was conducted with 107 cases of SC and 200 population-based controls in Chuzhou district, Huaian, Jiangsu province, China. The epidemiological data were collected, and DNA of peripheral blood leukocytes was obtained from all of the subjects..MTHFR genotypes were detected by PCR-RFLP. RESULTS (1) The prevalence of the MTHFR C/T or T/T genotypes was found to be significantly different between controls (68.5%) and SC cases (79.4%,P=0.0416), the increased risk had an adjusted OR of 1.79 (95%C1:1.01-3.19). (2) Among subjects who had a low intake of garlic or Chinese onion, MTHFR C/T or T/T genotypes significantly increased the risk of developing SC. Among non-tea drinkers or among subjects who had a frequent intakeof meat, the carriers of the MTHFR C/T or T/T genotypes had a higher risk of SC than individuals with the C/C type MTHFR. CONCLUSION The polymorphism of MTHFR C677T was associated with increased risk of developing SC, and that individuals with differing genotypes may have different susceptibilities to SC, based on their exposure level to environmental factors.

  20. Ribonucleotide reductase and cancer: biological mechanisms and targeted therapies.

    Science.gov (United States)

    Aye, Y; Li, M; Long, M J C; Weiss, R S

    2015-04-16

    Accurate DNA replication and repair is essential for proper development, growth and tumor-free survival in all multicellular organisms. A key requirement for the maintenance of genomic integrity is the availability of adequate and balanced pools of deoxyribonucleoside triphosphates (dNTPs), the building blocks of DNA. Notably, dNTP pool alterations lead to genomic instability and have been linked to multiple human diseases, including mitochondrial disorders, susceptibility to viral infection and cancer. In this review, we discuss how a key regulator of dNTP biosynthesis in mammals, the enzyme ribonucleotide reductase (RNR), impacts cancer susceptibility and serves as a target for anti-cancer therapies. Because RNR-regulated dNTP production can influence DNA replication fidelity while also supporting genome-protecting DNA repair, RNR has complex and stage-specific roles in carcinogenesis. Nevertheless, cancer cells are dependent on RNR for de novo dNTP biosynthesis. Therefore, elevated RNR expression is a characteristic of many cancers, and an array of mechanistically distinct RNR inhibitors serve as effective agents for cancer treatment. The dNTP metabolism machinery, including RNR, has been exploited for therapeutic benefit for decades and remains an important target for cancer drug development. PMID:24909171

  1. Alkyl hydroperoxide reductase: a candidate Helicobacter pylori vaccine.

    Science.gov (United States)

    O'Riordan, Avril A; Morales, Veronica Athie; Mulligan, Linda; Faheem, Nazia; Windle, Henry J; Kelleher, Dermot P

    2012-06-01

    Helicobacter pylori (H. pylori) is the most important etiological agent of chronic active gastritis, peptic ulcer disease and gastric cancer. The aim of this study was to evaluate the efficacy of alkyl hydroperoxide reductase (AhpC) and mannosylated AhpC (mAhpC) as candidate vaccines in the C57BL/6J mouse model of H. pylori infection. Recombinant AhpC was cloned, over-expressed and purified in an unmodified form and was also engineered to incorporate N and C-terminal mannose residues when expressed in the yeast Pichia pastoris. Mice were immunized systemically and mucosally with AhpC and systemically with mAhpC prior to challenge with H. pylori. Serum IgG responses to AhpC were determined and quantitative culture was used to determine the efficacy of vaccination strategies. Systemic prophylactic immunization with AhpC/alum and mAhpC/alum conferred protection against infection in 55% and 77.3% of mice, respectively. Mucosal immunization with AhpC/cholera toxin did not protect against infection and elicited low levels of serum IgG in comparison with systemic immunization. These data support the use of AhpC as a potential vaccine candidate against H. pylori infection. PMID:22512976

  2. Loss of quinone reductase 2 function selectively facilitates learning behaviors.

    Science.gov (United States)

    Benoit, Charles-Etienne; Bastianetto, Stephane; Brouillette, Jonathan; Tse, YiuChung; Boutin, Jean A; Delagrange, Philippe; Wong, TakPan; Sarret, Philippe; Quirion, Rémi

    2010-09-22

    High levels of reactive oxygen species (ROS) are associated with deficits in learning and memory with age as well as in Alzheimer's disease. Using DNA microarray, we demonstrated the overexpression of quinone reductase 2 (QR2) in the hippocampus in two models of learning deficits, namely the aged memory impaired rats and the scopolamine-induced amnesia model. QR2 is a cytosolic flavoprotein that catalyzes the reduction of its substrate and enhances the production of damaging activated quinone and ROS. QR2-like immunostaining is enriched in cerebral structures associated with learning behaviors, such as the hippocampal formation and the temporofrontal cortex of rat, mouse, and human brains. In cultured rat embryonic hippocampal neurons, selective inhibitors of QR2, namely S26695 and S29434, protected against menadione-induced cell death by reversing its proapoptotic action. S26695 (8 mg/kg) also significantly inhibited scopolamine-induced amnesia. Interestingly, adult QR2 knock-out mice demonstrated enhanced learning abilities in various tasks, including Morris water maze, object recognition, and rotarod performance test. Other behaviors related to anxiety (elevated plus maze), depression (forced swim), and schizophrenia (prepulse inhibition) were not affected in QR2-deficient mice. Together, these data suggest a role for QR2 in cognitive behaviors with QR2 inhibitors possibly representing a novel therapeutic strategy toward the treatment of learning deficits especially observed in the aged brain. PMID:20861374

  3. Determination of Nitrate Reductase Assay Depending on the Microbial Growth

    International Nuclear Information System (INIS)

    A rapid micro-dilution assay for determination of the antimicrobial susceptibility of different bacterial isolates was developed. This assay is based on the ability of the most of viable organisms to reduce nitrates. The MIC or MBC could be determined by nitrate reductase (NR) only after 30 to 90 min of incubation depending on the behaviour of microbial growth. Bacterial viability is detected by a positive nitrite reduction rather than visible turbidity. The nitrate reduction assay was compared with standard micro-assay using 250 isolates of different taxa against 10 antibiotics belonging to different classes. An excellent agreement of 82.5 % was found between the two methods and only 17.5 % of 1794 trials showed difference in the determined MIC by tow-dilution interval above or below the MIC determined by the turbidimetric method under the same test conditions. However, the nitrate reduction assay was more rapid and sensitive in detecting viable bacteria and so, established an accurate estimate of the minimal inhibitory concentration (MIC) or the minimal bacterial concentration (MBC). The nitrate reduction assay offers the additional advantage that it could be used to determine the MBC without having to subculture the broth. 232 cases of resistance were detected by NR and 4 different media were tested for susceptibility test. The bacterial isolates were exposed to ultra violet (UV) light for different period

  4. Aldose reductase inhibition improves nerve conduction velocity in diabetic patients.

    Science.gov (United States)

    Judzewitsch, R G; Jaspan, J B; Polonsky, K S; Weinberg, C R; Halter, J B; Halar, E; Pfeifer, M A; Vukadinovic, C; Bernstein, L; Schneider, M; Liang, K Y; Gabbay, K H; Rubenstein, A H; Porte, D

    1983-01-20

    To assess the potential role of polyol-pathway activity in diabetic neuropathy, we measured the effects of sorbinil--a potent inhibitor of the key polyol-pathway enzyme aldose reductase--on nerve conduction velocity in 39 stable diabetics in a randomized, double-blind, cross-over trial. During nine weeks of treatment with sorbinil (250 mg per day), nerve conduction velocity was greater than during a nine-week placebo period for all three nerves tested: the peroneal motor nerve (mean increase [+/- S.E.M.], 0.70 +/- 0.24 m per second, P less than 0.008), the median motor nerve (mean increase, 0.66 +/- 0.27, P less than 0.005), and the median sensory nerve (mean increase, 1.16 +/- 0.50, P less than 0.035). Conduction velocity for all three nerves declined significantly within three weeks after cessation of the drug. These effects of sorbinil were not related to glycemic control, which was constant during the study. Although the effect of sorbinil in improving nerve conduction velocity in diabetics was small, the findings suggest that polyol-pathway activity contributes to slowed nerve conduction in diabetics. The clinical applicability of these observations remains to be determined, but they encourage further exploration of this approach to the treatment or prevention of diabetic neuropathy. PMID:6401351

  5. Glyoxalase 1 and glutathione reductase 1 regulate anxiety in mice.

    Science.gov (United States)

    Hovatta, Iiris; Tennant, Richard S; Helton, Robert; Marr, Robert A; Singer, Oded; Redwine, Jeffrey M; Ellison, Julie A; Schadt, Eric E; Verma, Inder M; Lockhart, David J; Barlow, Carrolee

    2005-12-01

    Anxiety and fear are normal emotional responses to threatening situations. In human anxiety disorders--such as panic disorder, obsessive-compulsive disorder, post-traumatic stress disorder, social phobia, specific phobias and generalized anxiety disorder--these responses are exaggerated. The molecular mechanisms involved in the regulation of normal and pathological anxiety are mostly unknown. However, the availability of different inbred strains of mice offers an excellent model system in which to study the genetics of certain behavioural phenotypes. Here we report, using a combination of behavioural analysis of six inbred mouse strains with quantitative gene expression profiling of several brain regions, the identification of 17 genes with expression patterns that correlate with anxiety-like behavioural phenotypes. To determine if two of the genes, glyoxalase 1 and glutathione reductase 1, have a causal role in the genesis of anxiety, we performed genetic manipulation using lentivirus-mediated gene transfer. Local overexpression of these genes in the mouse brain resulted in increased anxiety-like behaviour, while local inhibition of glyoxalase 1 expression by RNA interference decreased the anxiety-like behaviour. Both of these genes are involved in oxidative stress metabolism, linking this pathway with anxiety-related behaviour. PMID:16244648

  6. Postperfusion lung syndrome: Respiratory mechanics, respiratory indices and biomarkers

    Directory of Open Access Journals (Sweden)

    Shi-Min Yuan

    2015-01-01

    Full Text Available Postperfusion lung syndrome is rare but lethal. Secondary inflammatory response was the popularly accepted theory for the underlying etiology. Respiratory index (RI and arterial oxygen tension/fractional inspired oxygen can be reliable indices for the diagnosis of this syndrome as X-ray appearance is always insignificant at the early stage of the onset. Evaluations of extravascular lung water content and pulmonary compliance are also helpful in the definite diagnosis. Multiorgan failure and triple acid-base disturbances that might develop secondary to postperfusion lung syndrome are responsible for the poor prognosis and increased mortality rather than postperfusion lung syndrome itself. Mechanical ventilation with low tidal volume (TV and proper positive end-expiratory pressure can be an effective treatment strategy. Use of ulinastatin and propofol may benefit the patients through different mechanisms.

  7. Feed-forward control of prostate growth: dihydrotestosterone induces expression of its own biosynthetic enzyme, steroid 5 alpha-reductase.

    OpenAIRE

    George, F W; Russell, D.W.; Wilson, J. D.

    1991-01-01

    Dihydrotestosterone, the primary mediator of prostate growth, is synthesized in target tissues from the circulating androgen testosterone through the action of steroid 5 alpha-reductase (EC 1.3.99.5). The expression of 5 alpha-reductase and the level of 5 alpha-reductase messenger RNA in rat ventral prostate are regulated by androgens. To determine whether this control is mediated by dihydrotestosterone or testosterone, we investigated the effect of finasteride, a potent inhibitor of steroid ...

  8. Nitrite and Nitrous Oxide Reductase Regulation by Nitrogen Oxides in Rhodobacter sphaeroides f. sp. denitrificans IL106

    OpenAIRE

    Sabaty, Monique; Schwintner, Carole; Cahors, Sandrine; Richaud, Pierre; Verméglio, Andre

    1999-01-01

    We have cloned the nap locus encoding the periplasmic nitrate reductase in Rhodobacter sphaeroides f. sp. denitrificans IL106. A mutant with this enzyme deleted is unable to grow under denitrifying conditions. Biochemical analysis of this mutant shows that in contrast to the wild-type strain, the level of synthesis of the nitrite and N2O reductases is not increased by the addition of nitrate. Growth under denitrifying conditions and induction of N oxide reductase synthesis are both restored b...

  9. Expression, purification, crystallization and preliminary X-ray analysis of perakine reductase, a new member of the aldo-keto reductase enzyme superfamily from higher plants

    International Nuclear Information System (INIS)

    Perakine reductase, a novel member of the aldo-keto reductase enzyme superfamily of higher plants, is involved in the biosynthesis of monoterpenoid indole alkaloids in the Indian medicinal plant Rauvolfia serpentina. The enzyme has been crystallized in C-centered orthorhombic space group and diffracts to 2.0 Å resolution. Perakine reductase (PR) is a novel member of the aldo-keto reductase enzyme superfamily from higher plants. PR from the plant Rauvolfia serpentina is involved in the biosynthesis of monoterpenoid indole alkaloids by performing NADPH-dependent reduction of perakine, yielding raucaffrinoline. However, PR can also reduce cinnamic aldehyde and some of its derivatives. After heterologous expression of a triple mutant of PR in Escherichia coli, crystals of the purified and methylated enzyme were obtained by the hanging-drop vapour-diffusion technique at 293 K with 100 mM sodium citrate pH 5.6 and 27% PEG 4000 as precipitant. Crystals belong to space group C2221 and diffract to 2.0 Å, with unit-cell parameters a = 58.9, b = 93.0, c = 143.4 Å

  10. Respiratory rate assessment from photoplethysmographic imaging.

    Science.gov (United States)

    Karlen, Walter; Garde, Ainara; Myers, Dorothy; Scheffer, Cornie; Ansermino, J Mark; Dumont, Guy A

    2014-01-01

    We present a study investigating the suitability of a respiratory rate estimation algorithm applied to photoplethysmographic imaging on a mobile phone. The algorithm consists of a cascade of previously developed signal processing methods to detect features and extract respiratory induced variations in photoplethysmogram signals to estimate respiratory rate. With custom-built software on an Android phone (Camera Oximeter), contact photoplethysmographic imaging videos were recorded using the integrated camera from 19 healthy adults breathing spontaneously at respiratory rates between 6 and 40 breaths/min. Capnometry was simultaneously recorded to obtain reference respiratory rates. Two hundred and ninety-eight Camera Oximeter recordings were available for analysis. The algorithm detected 22 recordings with poor photoplethysmogram quality and 46 recordings with insufficient respiratory information. Of the 232 remaining recordings, a root mean square error of 5.9 breaths/min and a median absolute error of 2.3 breaths/min was obtained. The study showed that it is feasible to estimate respiratory rates by placing a finger on a mobile phone camera, but that it becomes increasingly challenging at respiratory rates higher than 20 breaths/min. PMID:25571214

  11. Diagnosing and treating respiratory syncytial virus bronchiolitis.

    Science.gov (United States)

    Napierkowski, Daria B

    2016-09-22

    Respiratory syncytial virus (RSV) is one of the major causes of respiratory tract illness in children and can lead to significant infection and death. This article discusses the incidence, clinical presentation, diagnosis, current treatment, and prevention options to successfully diagnose and treat infections caused by RSV. PMID:27552683

  12. Perceived Competence and Comfort in Respiratory Protection

    Science.gov (United States)

    Burgel, Barbara J.; Novak, Debra; Burns, Candace M.; Byrd, Annette; Carpenter, Holly; Gruden, MaryAnn; Lachat, Ann; Taormina, Deborah

    2015-01-01

    In response to the Institute of Medicine (2011) report Occupational Health Nurses and Respiratory Protection: Improving Education and Training, a nationwide survey was conducted in May 2012 to assess occupational health nurses’ educational preparation, roles, responsibilities, and training needs in respiratory protection. More than 2,000 occupational health nurses responded; 83% perceived themselves as competent, proficient, or expert in respiratory protection, reporting moderate comfort with 12 respiratory program elements. If occupational health nurses had primary responsibility for the respiratory protection program, they were more likely to perceive higher competence and more comfort in respiratory protection, after controlling for occupational health nursing experience, highest education, occupational health nursing certification, industry sector, Association of Occupational Health Professionals in Healthcare membership, taking a National Institute for Occupational Safety and Health spirometry course in the prior 5 years, and perceiving a positive safety culture at work. These survey results document high perceived competence and comfort in respiratory protection. These findings support the development of targeted educational programs and interprofessional competencies for respiratory protection. PMID:23429638

  13. Abnormal lung lymphatics and respiratory failure.

    OpenAIRE

    Moss, S F; Currie, D C; Sheffield, E A; M. Baxter; Corrin, B.; Evans, T. W.

    1989-01-01

    A 65 year old man presented with respiratory failure, pleural effusions, fine reticulonodular shadowing on a chest radiograph, and severe impairment of carbon monoxide diffusing capacity (transfer factor). Open lung biopsy showed only dilated pleural and subpleural lymphatic channels. Hypoplastic deep pulmonary lymphatics may have led to respiratory failure.

  14. Detection of respiratory pathogens in aerosols from acutely infected pigs

    Science.gov (United States)

    Infectious agents that cause respiratory disease in pigs include porcine reproductive respiratory syndrome virus (PRRSV), porcine circovirus type 2 (PCV2), swine influenza virus (SIV), porcine respiratory corona virus (PRCV), Mycoplasma hyopneumoniae, and Bordetella bronchiseptica. The objective of...

  15. Perioperative modifications of respiratory function.

    LENUS (Irish Health Repository)

    Duggan, Michelle

    2012-01-31

    Postoperative pulmonary complications contribute considerably to morbidity and mortality, especially after major thoracic or abdominal surgery. Clinically relevant pulmonary complications include the exacerbation of underlying chronic lung disease, bronchospasm, atelectasis, pneumonia and respiratory failure with prolonged mechanical ventilation. Risk factors for postoperative pulmonary complications include patient-related risk factors (e.g., chronic obstructive pulmonary disease (COPD), tobacco smoking and increasing age) as well as procedure-related risk factors (e.g., site of surgery, duration of surgery and general vs. regional anaesthesia). Careful history taking and a thorough physical examination may be the most sensitive ways to identify at-risk patients. Pulmonary function tests are not suitable as a general screen to assess risk of postoperative pulmonary complications. Strategies to reduce the risk of postoperative pulmonary complications include smoking cessation, inspiratory muscle training, optimising nutritional status and intra-operative strategies. Postoperative care should include lung expansion manoeuvres and adequate pain control.

  16. The respiratory system in equations

    CERN Document Server

    Maury, Bertrand

    2013-01-01

    The book proposes an introduction to the mathematical modeling of the respiratory system. A detailed introduction on the physiological aspects makes it accessible to a large audience without any prior knowledge on the lung. Different levels of description are proposed, from the lumped models with a small number of parameters (Ordinary Differential Equations), up to infinite dimensional models based on Partial Differential Equations. Besides these two types of differential equations, two chapters are dedicated to resistive networks, and to the way they can be used to investigate the dependence of the resistance of the lung upon geometrical characteristics. The theoretical analysis of the various models is provided, together with state-of-the-art techniques to compute approximate solutions, allowing comparisons with experimental measurements. The book contains several exercises, most of which are accessible to advanced undergraduate students.

  17. Stem cells and respiratory diseases

    Directory of Open Access Journals (Sweden)

    Soraia Carvalho Abreu

    2008-12-01

    Full Text Available Stem cells have a multitude of clinical implications in the lung. This article is a critical review that includes clinical and experimental studies of MedLine and SciElo database in the last 10 years, where we highlight the effects of stem cell therapy in acute respiratory distress syndrome or more chronic disorders such as lung fibrosis and emphysema. Although, many studies have shown the beneficial effects of stem cells in lung development, repair and remodeling; some important questions need to be answered to better understand the mechanisms that control cell division and differentiation, therefore enabling the use of cell therapy in human respiratory diseases.As células-tronco têm uma infinidade de implicações clínicas no pulmão. Este artigo é uma revisão crítica que inclui estudos clínicos e experimentais advindos do banco de dados do MEDLINE e SciElo nos últimos 10 anos, onde foram destacados os efeitos da terapia celular na síndrome do desconforto respiratório agudo ou doenças mais crônicas, como fibrose pulmonar e enfisema. Apesar de muitos estudos demonstrarem os efeitos benéficos das células-tronco no desenvolvimento, reparo e remodelamento pulmonar; algumas questões ainda precisam ser respondidas para um melhor entendimento dos mecanismos que controlam a divisão celular e diferenciação, permitindo o uso da terapia celular nas doenças respiratórias.

  18. Respiratory load compensation in uremia.

    Science.gov (United States)

    Heinzmann, H G; Kassabian, J; Naqui, M N; Lavietes, M H

    1981-01-01

    The clinical significance of respiratory-system load-compensation is unknown. We have measured the responses to random presentation of single, elastic inspiratory loads in 36 subjects: 8 normal personnel (N), 9 with obesity (O), 10 with chronic renal failure under hemodialysis (H), 5 with pneumonia (P), and 4 with interstitial lung disease (CILD). We have expressed these responses as: (1) the ratio of elastance (or rigidity) of the system during loaded breathing to the elastance without loading (E'RS/ERS); (2) the ratio of tidal volume (VT) achieved when breathing from an inspiratory load to the VT predicted in the absence of load compensation (VTL/VTP); (3) the ratio of inspiratory flow rates during loaded and unloaded breaths; (4) the ratio of inspiratory time of loaded and unloaded breaths. We found E'RS/ERS in the O, H and P groups less than that of either CILD patients or N controls (F = 6.79; p less than 0.001). Passive elastance (ERS) although greater in groups O and H than in N (F = 3.88; p less than 0.025) did not account for the difference i E'RS in all groups. When expressed as VTL/VTP, the response to a 37-cm H2O/l load for groups H, O and P was less than that for N (F = 5.51; p less than 0.05). Diminished inspiratory time was observed in H, O and P patients when inspiring from this load. In contrast, inspiratory flow did not differ from that of normal subjects. Nerve conduction velocity was slightly reduced or normal in the H patients. Respiratory load compensation is deficient in H, O and P patients. The mechanism, which does not involve peripheral neuropathy, is unclear. PMID:7244394

  19. Pyrobaculum Yellowstonensis Strain WP30 Respires On Elemental Sulfur And/or Arsenate in Circumneutral Sulfidic Sediments of Yellowstone National Park

    Energy Technology Data Exchange (ETDEWEB)

    Jay, Z.; Beam, Jake; Dohnalkova, Alice; Lohmayer, R.; Bodle, B.; Planer-Friedrich, B.; Romine, Margaret F.; Inskeep, William

    2015-09-15

    Thermoproteales populations (phylum Crenarchaeota) are abundant in high-25 temperature (>70° C) environments of Yellowstone National Park (YNP) and are important in mediating biogeochemical cycles of sulfur, arsenic and carbon. The objectives of this study were to determine specific physiological attributes of the isolate Pyrobaculum yellowstonensis strain WP30, which was obtained from an elemental sulfur sediment (Joseph’s Coat Hot Spring [JCHS]; 80 °C; pH 6.1), and relate this organism to geochemical processes occurring in situ. Strain WP30 is a chemoheterotroph that utilizes organic carbon as a source of carbon and electrons and requires elemental sulfur and/or arsenic as electron acceptors. Growth in the presence of elemental sulfur and arsenate resulted in the production of thioarsenates and polysulfides relative to sterile controls. The complete genome of this organism was sequenced (1.99 Mb, 58 % G+C) and revealed numerous metabolic pathways for the degradation of carbohydrates, amino acids and lipids, multiple dimethylsulfoxide molybdopterin (DMSO-MPT) oxidoreductase genes, which are implicated in the reduction of sulfur and arsenic, and pathways for the de novo synthesis of nearly all required cofactors and metabolites. Comparative genomics of P. yellowstonensis versus assembled metagenome sequence from JCHS showed that this organisms is highly-related (~95% average nucleotide identity) to in situ populations. The physiological attributes and metabolic capabilities of P. yellowstonensis provide importanat information towards understanding the distribution and function of these populations in YNP.

  20. Sequential Enrichment with Titania-coated Magnetic Mesoporous Hollow Silica Microspheres and Zirconium Arsenate-modified Magnetic Nanoparticles for the Study of Phosphoproteome of HL60 Cells

    Science.gov (United States)

    Yu, Qiong-Wei; Li, Xiao-Shui; Xiao, Yongsheng; Guo, Lei; Zhang, Fan; Cai, Qian; Feng, Yu-Qi; Yuan, Bi-Feng; Wang, Yinsheng

    2014-01-01

    As one of the most important types of post-translational modifications, reversible phosphorylation of proteins plays crucial roles in a large number of biological processes. However, owing to the relatively low abundance and dynamic nature of phosphorylation and the presence of the unphosphorylated peptides in large excess, phosphopeptide enrichment is indispensable in large-scale phosphoproteomic analysis. Metal oxides including titanium dioxide have become prominent affinity materials to enrich phosphopeptides prior to their analysis using liquid chromatography-mass spectrometry (LC-MS). In the current study, we established a novel strategy, which encompassed strong cation exchange chromatography, sequential enrichment of phosphopeptides using titania-coated magnetic mesoporous hollow silica microspheres (TiO2/MHMSS) and zirconium arsenate-modified magnetic nanoparticles (ZrAs-Fe3O4@SiO2), and LC-MS/MS analysis, for the proteome-wide identification of phosphosites of proteins in HL60 cells. In total, we were able to identify 11579 unique phosphorylation sites in 3432 unique proteins. Additionally, our results suggested that TiO2/MHMSS and ZrAs-Fe3O4@SiO2 are complementary in phosphopeptide enrichment, where the two types of materials displayed preferential binding of peptides carrying multiple and single phosphorylation sites, respectively. PMID:25262027

  1. Intraspecific differences in effects of co-contamination of cadmium and arsenate on early seedling growth and metal uptake by wheat

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A hydroponic experiment was carried out to study intraspecific differences in the effects of different concentrations of cadmium (Cd)(0-10 mg/L) and arsenate (As(V)) (0-8 mg/L) on the growth parameters and accumulation of Cd and As in six wheat varieties Jing-9428, Duokang-1, Jingdong-11, Jing-411, Jingdong-8 and Zhongmai-8. The endpoints of wheat seedlings, including seed germination,biomass, root length and shoot height, decreased with increasing the Cd and As concentrations. Significant differences in seed germination, biomass, root length, shoot height and the accumulation of Cd and As were observed between the treatments and among the varieties (p < 0.05). The lethal dosage 50% were about 20, 80, 60, 60, 80 and 20 mg As/L for Jing-9428, Duokang-1, Jingdong-11,Jing-411, Jingdong-8 and Zhongmai-8, respectively, and the corresponding values for Cd were about 30, 80, 20, 40, 60 and 10 mg Cd/L, respectively. Among the six varieties, Duokang-1 was found to be the most resistant to Cd and As toxicity, and Zhongmai-8 was the most sensitive to Cd and As co-contamination. The resistance of the six varieties was found dependant on the seedling uptake of Cd and As. Duokang-1 was the most suitable for cultivation in Cd and As co-contaminated soils.

  2. Methylenetetrahydrofolate reductase gene polymorphism in Indian stroke patients

    Directory of Open Access Journals (Sweden)

    Kalita J

    2006-01-01

    Full Text Available Background and Aims: In view of the prevailing controversy about the role of Methylenetetrahydrofolate reductase (MTHFR C677T mutation in stroke and paucity of studies from India, this study has been undertaken to evaluate MTHFR C677T gene polymorphism in consecutive ischemic stroke patients and correlate these with folic acid, homocysteine (Hcy and conventional risk factors. Settings and Design: Ischemic stroke patients prospectively evaluated in a tertiary care teaching hospital. Materials and Methods: Computerized tomography proven ischemic stroke patients were prospectively evaluated including clinical, family history of stroke, dietary habits and addictions. Their fasting and postprandial blood sugar, lipid profile, vitamin B12, folic acid and MTHFR gene analysis were done. Statistical Analysis: MTHFR gene polymorphism was correlated with serum folic acid, Vitamin B12 and Hcy levels; family history of stroke in first-degree relatives; and dietary habits; employing Chi-square test. Results: There were 58 patients with ischemic stroke, whose mean age was 50 (4-79 years; among them, 10 were females. MTHFR gene polymorphism was present in 19 (32.8% patients, 3 were homozygous and 16 were heterozygous. Both serum folate and B12 levels were low in 29 (50% patients and Hcy in 48 (83%. Hypertension was present in 28 (48% patients, diabetes in 12 (21%, hyperlipidemia in 52 (90%, smoking in 17 (29%, obesity in 1 (1.7% and family history of stroke in first-degree relatives in 13 (22.4%. There was no significant relationship of MTHFR gene polymorphism with folic acid, B12, Hcy levels, dietary habits and number of risk factors. Vitamin B12 level was low in vegetarians ( P Conclusion: MTHFR gene polymorphism was found in one-third of patients with ischemic stroke and was insignificantly associated with higher frequency of elevated Hcy.

  3. Metabolism of bupropion by carbonyl reductases in liver and intestine.

    Science.gov (United States)

    Connarn, Jamie N; Zhang, Xinyuan; Babiskin, Andrew; Sun, Duxin

    2015-07-01

    Bupropion's metabolism and the formation of hydroxybupropion in the liver by cytochrome P450 2B6 (CYP2B6) has been extensively studied; however, the metabolism and formation of erythro/threohydrobupropion in the liver and intestine by carbonyl reductases (CR) has not been well characterized. The purpose of this investigation was to compare the relative contribution of the two metabolism pathways of bupropion (by CYP2B6 and CR) in the subcellular fractions of liver and intestine and to identify the CRs responsible for erythro/threohydrobupropion formation in the liver and the intestine. The results showed that the liver microsome generated the highest amount of hydroxybupropion (Vmax = 131 pmol/min per milligram, Km = 87 μM). In addition, liver microsome and S9 fractions formed similar levels of threohydrobupropion by CR (Vmax = 98-99 pmol/min per milligram and Km = 186-265 μM). Interestingly, the liver has similar capability to form hydroxybupropion (by CYP2B6) and threohydrobupropion (by CR). In contrast, none of the intestinal fractions generate hydroxybupropion, suggesting that the intestine does not have CYP2B6 available for metabolism of bupropion. However, intestinal S9 fraction formed threohydrobupropion to the extent of 25% of the amount of threohydrobupropion formed by liver S9 fraction. Enzyme inhibition and Western blots identified that 11β-dehydrogenase isozyme 1 in the liver microsome fraction is mainly responsible for the formation of threohydrobupropion, and in the intestine AKR7 may be responsible for the same metabolite formation. These quantitative comparisons of bupropion metabolism by CR in the liver and intestine may provide new insight into its efficacy and side effects with respect to these metabolites. PMID:25904761

  4. Short-chain dehydrogenases/reductases in cyanobacteria.

    Science.gov (United States)

    Kramm, Anneke; Kisiela, Michael; Schulz, Rüdiger; Maser, Edmund

    2012-03-01

    The short-chain dehydrogenases/reductases (SDRs) represent a large superfamily of enzymes, most of which are NAD(H)-dependent or NADP(H)-dependent oxidoreductases. They display a wide substrate spectrum, including steroids, alcohols, sugars, aromatic compounds, and xenobiotics. On the basis of characteristic sequence motifs, the SDRs are subdivided into two main (classical and extended) and three smaller (divergent, intermediate, and complex) families. Despite low residue identities in pairwise comparisons, the three-dimensional structure among the SDRs is conserved and shows a typical Rossmann fold. Here, we used a bioinformatics approach to determine whether and which SDRs are present in cyanobacteria, microorganisms that played an important role in our ecosystem as the first oxygen producers. Cyanobacterial SDRs could indeed be identified, and were clustered according to the SDR classification system. Furthermore, because of the early availability of its genome sequence and the easy application of transformation methods, Synechocystis sp. PCC 6803, one of the most important cyanobacterial strains, was chosen as the model organism for this phylum. Synechocystis sp. SDRs were further analysed with bioinformatics tools, such as hidden Markov models (HMMs). It became evident that several cyanobacterial SDRs show remarkable sequence identities with SDRs in other organisms. These so-called 'homologous' proteins exist in plants, model organisms such as Drosophila melanogaster and Caenorhabditis  elegans, and even in humans. As sequence identities of up to 60% were found between Synechocystis and humans, it was concluded that SDRs seemed to have been well conserved during evolution, even after dramatic terrestrial changes such as the conversion of the early reducing atmosphere to an oxidizing one by cyanobacteria. PMID:22251568

  5. Aldo-keto reductase (AKR) superfamily: genomics and annotation.

    Science.gov (United States)

    Mindnich, Rebekka D; Penning, Trevor M

    2009-07-01

    Aldo-keto reductases (AKRs) are phase I metabolising enzymes that catalyse the reduced nicotinamide adenine dinucleotide (phosphate) (NAD(P)H)-dependent reduction of carbonyl groups to yield primary and secondary alcohols on a wide range of substrates, including aliphatic and aromatic aldehydes and ketones, ketoprostaglandins, ketosteroids and xenobiotics. In so doing they functionalise the carbonyl group for conjugation (phase II enzyme reactions). Although functionally diverse, AKRs form a protein superfamily based on their high sequence identity and common protein fold, the (alpha/beta) 8 -barrel structure. Well over 150 AKR enzymes, from diverse organisms, have been annotated so far and given systematic names according to a nomenclature that is based on multiple protein sequence alignment and degree of identity. Annotation of non-vertebrate AKRs at the National Center for Biotechnology Information or Vertebrate Genome Annotation (vega) database does not often include the systematic nomenclature name, so the most comprehensive overview of all annotated AKRs is found on the AKR website (http://www.med.upenn.edu/akr/). This site also hosts links to more detailed and specialised information (eg on crystal structures, gene expression and single nucleotide polymorphisms [SNPs]). The protein-based AKR nomenclature allows unambiguous identification of a given enzyme but does not reflect the wealth of genomic and transcriptomic variation that exists in the various databases. In this context, identification of putative new AKRs and their distinction from pseudogenes are challenging. This review provides a short summary of the characteristic features of AKR biochemistry and structure that have been reviewed in great detail elsewhere, and focuses mainly on nomenclature and database entries of human AKRs that so far have not been subject to systematic annotation. Recent developments in the annotation of SNP and transcript variance in AKRs are also summarised. PMID:19706366

  6. Aldo-keto reductase (AKR superfamily: Genomics and annotation

    Directory of Open Access Journals (Sweden)

    Mindnich Rebekka D

    2009-07-01

    Full Text Available Abstract Aldo-keto reductases (AKRs are phase I metabolising enzymes that catalyse the reduced nicotinamide adenine dinucleotide (phosphate (NAD(PH-dependent reduction of carbonyl groups to yield primary and secondary alcohols on a wide range of substrates, including aliphatic and aromatic aldehydes and ketones, ketoprostaglan-dins, ketosteroids and xenobiotics. In so doing they functionalise the carbonyl group for conjugation (phase II enzyme reactions. Although functionally diverse, AKRs form a protein superfamily based on their high sequence identity and common protein fold, the (α/(β8-barrel structure. Well over 150 AKR enzymes, from diverse organisms, have been annotated so far and given systematic names according to a nomenclature that is based on multiple protein sequence alignment and degree of identity. Annotation of non-vertebrate AKRs at the National Center for Biotechnology Information or Vertebrate Genome Annotation (vega database does not often include the systematic nomenclature name, so the most comprehensive overview of all annotated AKRs is found on the AKR website (http://www.med.upenn.edu/akr/. This site also hosts links to more detailed and specialised information (eg on crystal structures, gene expression and single nucleotide polymorphisms [SNPs]. The protein-based AKR nomenclature allows unambiguous identification of a given enzyme but does not reflect the wealth of genomic and transcriptomic variation that exists in the various databases. In this context, identification of putative new AKRs and their distinction from pseudogenes are challenging. This review provides a short summary of the characteristic features of AKR biochemistry and structure that have been reviewed in great detail elsewhere, and focuses mainly on nomenclature and database entries of human AKRs that so far have not been subject to systematic annotation. Recent developments in the annotation of SNP and transcript variance in AKRs are also summarised.

  7. Expression of 5α-Reductase Type 2 Gene in Human Testis, Epididymis and Vas Deferens

    Institute of Scientific and Technical Information of China (English)

    刘德瑜; 吴燕婉; 罗宏志; 张桂元

    2002-01-01

    Objectives To study the expression pattern of 5α-reductase type 2 gene in human malereproductive organsMethods The expression level of 5α-reductase type 2 gene inhuman testis, epididymisand vas deferens tissues was determined by in situ hybridization using Digoxin labeled5α-reductase type 2 cRNA probe.Results The brown granules of hybridizing signals distributed in the cytoplasm ofSertoli and Leydig cells of the testis, the principle cells of epididymis and the epithe-lial cells of vas deferens, but there was no positive signal in the nuclei of above-men-tioned cells. No positive signal was observed in germ cells, basement of the testis,interstium of epididymis and basement, as well as smooth muscle of vas deferens.Conclusion This study confirmed that the 5α-reductase type 2 gene expressed in Ser-toli, Leydig cells of the testis, and the principle cells of epididymis. The expressionpattern of the gene in these cells in human was similar to that of rat and monkey. Thepresence of 5a-reductase type 2 gene in epithelial cells of the vas deferens suggested itmight possess an important physiological role in human reproduction.

  8. Pseudomonas stutzeri N2O reductase contains CuA-type sites

    International Nuclear Information System (INIS)

    N2O reductase (N2O → N2) is the terminal enzyme in the energy-conserving denitrification pathway of soil and marine denitrifying bacteria. The protein is composed of two identical subunits and contains eight copper ions per enzyme molecule. The magnetic circular dichroism spectrum of resting (oxidized) N2O reductase is strikingly similar to the magnetic circular dichroism spectrum of the CuA site in mammalian cytochrome c oxidase and is unlike the magnetic circular dichroism spectra of all other biological copper chromophores obtained to data. Sulfur (or chlorine) scatterers are required to fit the copper extended x-ray absorption fine structure data of both the oxidized and reduced forms of N2O reductase. Satisfactory fits require a Cu-N or Cu-O interaction at 2.0 angstrom, a Cu-(S, Cl) interaction at 2.3 angstrom and an additional Cu-(S, Cl) interaction at ∼ 2.6 angstrom (oxidized) or ∼ 2.7 angstrom (reduced). Comparison of the N2O reductase sequence, determined by translating the structural NosZ gene, with cytochrome c oxidase subunit II sequences from several sources indicates that a Gly-Xaa-Xaa-Xaa-Xaa-Xaa-Cys-Ser-Xaa-Xaa-Cys-Xaa-Xaa-Xaa-Xaa-Xaa-His stretch if high conserved. This sequence contains three of the probable ligands in a CuA-type site Collectively these data establish that Pseudomonas stutzeri N2O reductase contains CuA-type sites

  9. INHIBITORY ACTIVITY OF FLAVONOIDS ON THE LENS ALDOSE REDUCTASE OF HEALTHY AND DIABETIC RATS

    Directory of Open Access Journals (Sweden)

    M. T. Goodarzi

    2006-05-01

    Full Text Available Aldose reductase is a critical enzyme in the polyol pathway that plays an important role in diabetes mellitus. Inhibition of the activity of this enzyme can prevent cataract in diabetic patients’lenses. In this study the inhibitory effect of two flavonoids, quercetin and naringin, in the activity of aldose reductase in streptozotocin-induced diabetic and healthy rats were investigated. Thirty male rats were divided in six groups. The first, second and third group were healthy rats that received water,quercetin and naringin, respectively. The fourth, fifth and sixth groups were streptozocin-induced diabetic rats that received water, quercetin and naringin, respectively. These rats were fed orally in a definite dose from each substance for 12 days. After this period rats were scarified and their lenses were separated and homogenized. The activity of aldose reductase was measured in each homogenized sample separately. The effect of feeding of these substances in blood sugar was also determined. Aldose reductase activity was reduced 73 and 69 percent in diabetic rats fed by quercetin and naringin, respectively, and the difference compared to control group was significant. In healthy rats this reduction was 63 and 59 percent, respectively, and the difference was significant compared to those who did not receive flavonoids. It was concluded that these substances were effective in reduction of aldose reductase activity in vivo and consequently could delay the progress of cataract.

  10. Current status of 5α-reductase inhibitors in the treatment of benign hyperplasia of prostate

    Directory of Open Access Journals (Sweden)

    Kumar Vijay

    2008-04-01

    Full Text Available Benign prostatic hyperplasia (BPH is a common problem in aging men, which is associated with lower urinary tract symptoms. This condition is dependent on the presence of androgens for its progression, and medical therapy is the first-line treatment for BPH patients with moderate-to-severe symptoms and includes the use of either alpha 1-adrenergic blockers or 5α-reductase inhibitors. Adrenergic blocking drugs reduce the dynamic component while the 5α-reductase inhibitors reduce the static component of bladder outlet obstruction in BPH. By inhibiting the generation of active form of testosterone, viz., dihydrotestosterone, the 5α-reductase inhibitors not only reduce the symptoms of BPH but also decrease the need for surgery and further progression of BPH. Besides, prolonged use of combination of 5α-reductase inhibitors and alpha 1-adrenergic blockers has been found to be more beneficial than either of the two drugs given alone. This review gives a brief account of rationale and efficacy of treatment by 5α-reductase inhibitors in the management of BPH.

  11. Structural and biochemical properties of cloned and expressed human and rat steroid 5α-reductases

    International Nuclear Information System (INIS)

    The microsomal enzyme steroid 5α-reductase is responsible for the conversion of testosterone into the more potent androgen dihydrotestosterone. In man, this steroid acts on a variety of androgen-responsive target tissues to mediate such diverse endocrine processes as male sexual differentiation in the fetus and prostatic growth in men. Here we describe the isolation, structure, and expression of a cDNA encoding the human steroid 5α-reductase. A rat cDNA was used as a hybridization probe to screen a human prostate cDNA library. A 2.1-kilobase cDNA was identified and DNA sequence analysis indicated that the human steroid 5α-reductase was a hydrophobic protein of 259 amino acids with a predicted molecular weight of 29,462. A comparison of the human and rat protein sequences revealed a 60% identity. Transfection of expression vectors containing the human and rat cDNAs into simian COS cells resulted in the synthesis of high levels of steroid 5α-reductase enzyme activity. Both enzymes expressed in COS cells showed similar substrate specificities for naturally occurring steroid hormones. However, synthetic 4-azasteroids demonstrated marked differences in their abilities to inhibit the human and rat steroid 5α-reductases

  12. Management of respiratory symptoms in ALS.

    LENUS (Irish Health Repository)

    Hardiman, Orla

    2011-03-01

    Respiratory insufficiency is a frequent feature of ALS and is present in almost all cases at some stage of the illness. It is the commonest cause of death in ALS. FVC is used as important endpoint in many clinical trials, and in decision-making events for patients with ALS, although there are limitations to its predictive utility. There are multiple causes of respiratory muscle failure, all of which act to produce a progressive decline in pulmonary function. Diaphragmatic fatigue and weakness, coupled with respiratory muscle weakness, lead to reduced lung compliance and atelectasis. Increased secretions increase the risk of aspiration pneumonia, which further compromises respiratory function. Bulbar dysfunction can lead to nutritional deficiency, which in turn increases the fatigue of respiratory muscles. Early recognition of respiratory decline and symptomatic intervention, including non-invasive ventilation can significantly enhance both quality of life and life expectancy in ALS. Patients with respiratory failure should be advised to consider an advance directive to avoid emergency mechanical ventilation.

  13. Endothelin involvement in respiratory centre activity.

    Science.gov (United States)

    Albertini, M; Lafortuna, C L; Ciminaghi, B; Mazzola, S; Clement, M G

    2001-09-01

    To evaluate the role of endothelin (ET) in respiratory homeostasis we studied the effects of the ET(A) and ET(B) receptor blocking agent bosentan on respiratory mechanics and control in seven anaesthetised spontaneously breathing pigs, for 180 min after single bolus administration (20 mg/kg i.v.). The results show that the block of ET receptors induced a significant increase in compliance and decrease in resistance of the respiratory system, entailing a significant reduction of diaphragmatic electromyographic activity, without affecting the centroid frequency of the power spectrum. Bosentan administration induced a significant increase in tidal volume (V(T)), accompanied by a significant decrease in respiratory frequency, without any significant change in pulmonary ventilation, CO(2) arterial blood gas pressure or pH. Since the relationship between V(T) and inspiratory time remained substantially constant after bosentan administration, the changes in respiratory pattern appear to be the result of an upward shift in inspiratory off-switch threshold. Both inspiratory and expiratory times during occluded breathing were increased by block of ET receptors, suggesting also a central respiratory neuromodulator effect of ET. In conclusion the present results suggest that the block of ET receptors in spontaneously breathing pigs exerts a role on mechanical properties of the respiratory system as well as on peripheral and central mechanisms of breathing control. PMID:11728166

  14. SMART phones and the acute respiratory patient.

    LENUS (Irish Health Repository)

    Gleeson, L

    2012-05-01

    Definition of Respiratory Failure using PaO2 alone is confounded when patients are commenced on oxygen therapy prior to arterial blood gas (ABG) measurement. Furthermore, classification of Respiratory Failure as Type 1 or Type 2 using PaCO2 alone can give an inaccurate account of events as both types can co-exist. 100 consecutive presentations of acute respiratory distress were assessed initially using PaO2, and subsequently PaO2\\/FiO2 ratio, to diagnose Respiratory Failure. Respiratory Failure cases were classified as Type 1 or Type 2 initially using PaCO2, and subsequently alveolar-arterial (A-a) gradient. Any resultant change in management was documented. Of 100 presentations, an additional 16 cases were diagnosed as Respiratory Failure using PaO2\\/FiO2 ratio in place of PaO2 alone (p = 0.0338). Of 57 cases of Respiratory Failure, 22 cases classified as Type 2 using PaCO2 alone were reclassified as Type 1 using A-a gradient (p < 0.001). Of these 22 cases, management changed in 18.

  15. Management of respiratory symptoms in ALS.

    LENUS (Irish Health Repository)

    Hardiman, Orla

    2012-02-01

    Respiratory insufficiency is a frequent feature of ALS and is present in almost all cases at some stage of the illness. It is the commonest cause of death in ALS. FVC is used as important endpoint in many clinical trials, and in decision-making events for patients with ALS, although there are limitations to its predictive utility. There are multiple causes of respiratory muscle failure, all of which act to produce a progressive decline in pulmonary function. Diaphragmatic fatigue and weakness, coupled with respiratory muscle weakness, lead to reduced lung compliance and atelectasis. Increased secretions increase the risk of aspiration pneumonia, which further compromises respiratory function. Bulbar dysfunction can lead to nutritional deficiency, which in turn increases the fatigue of respiratory muscles. Early recognition of respiratory decline and symptomatic intervention, including non-invasive ventilation can significantly enhance both quality of life and life expectancy in ALS. Patients with respiratory failure should be advised to consider an advance directive to avoid emergency mechanical ventilation.

  16. Community structures and activity of denitrifying microbes in a forested catchment in central Japan: survey using nitrite reductase genes

    Science.gov (United States)

    Ohte, N.; Aoki, M.; Katsuyama, C.; Suwa, Y.; Tange, T.

    2012-12-01

    To elucidate the mechanisms of denitrification processes in the forested catchment, microbial ecological approaches have been applied in an experimental watershed that has previously investigated its hydrological processes. The study catchment is located in the Chiba prefecture in central Japan under the temperate Asian monsoon climate. Potential activities of denitrification of soil samples were measured by incubation experiments under anoxic condition associated with Na15NO3 addition. Existence and variety of microbes having nitrite reductase genes were investigated by PCR amplification, cloning and sequencings of nirK and nirS fragments after DNA extraction. Contrary to our early expectation that the potential denitrification activity was higher at deeper soil horizon with consistent groundwater residence than that in the surface soil, denitrification potential was higher in shallower soil horizons than deeper soils. This suggested that the deficiency of NO3- as a respiratory substrate for denitrifier occurred in deeper soils especially in the summer. However, high denitrification activity and presence of microbes having nirK and nirS in surface soils usually under aerobic condition was explainable by the fact that the majority of denitrifying bacteria have been recognized as a facultative anaerobic bacterium. This also suggests the possibility of that denitrification occurs even in the surface soils if the wet condition is provided by rainwater during and after a storm event. Community structures of microbes having nirK were different between near surface and deeper soil horizons, and ones having nirS was different between saturated zone (under groundwater table) and unsaturated soil horizons. These imply that microbial communities with nisK are sensitive to the concentration of soil organic matters and ones with nirS is sensitive to soil moisture contents.

  17. Pesticides and respiratory symptoms among farmers

    Directory of Open Access Journals (Sweden)

    Faria Neice Müller Xavier

    2005-01-01

    Full Text Available OBJECTIVE: Despite the intensive use of pesticides in agriculture there are few studies assessing the risk of respiratory conditions from this exposure. The study aimed at quantifying the prevalence of respiratory symptoms among farmers and evaluating its relationship with occupational use of pesticides and the prevalence of respiratory symptoms. METHODS: A cross-sectional study was conducted among 1,379 farmers from two municipalities of Southern Brazil in 1996. Frequency and type of chemical exposure and pesticide poisoning were recorded for both sexes. All subjects aged 15 years or older with at least 15 weekly hours of agricultural activity were interviewed. An adapted questionnaire developed by the American Thoracic Society was used for the assessment of respiratory symptoms. Multivariate logistic regression analysis was carried out. RESULTS: More than half (55% of interviewees were male. The prevalence of asthma symptoms was 12% and chronic respiratory disease symptoms was 22%. Higher odds ratios for both asthma (OR=1.51; 95% CI: 1.07-2.14 and chronic respiratory disease (OR=1.34; 95% CI 1.00-1.81 symptoms were found in women. Logistic regression analysis identified associations between many forms of exposure to pesticides and increased respiratory symptoms. Occurrence of pesticide poisoning was associated with higher prevalence of asthma symptoms (OR=1.54; 95% CI: 1.04-2.58 and chronic respiratory disease symptoms (OR=1.57; 95% CI: 1.08-2.28. CONCLUSIONS: In spite of causality limitations, the study results provide evidence that farming exposure to pesticides is associated with higher prevalence of respiratory symptoms, especially when the exposure is above two days per month.

  18. MEK2 regulates ribonucleotide reductase activity through functional interaction with ribonucleotide reductase small subunit p53R2.

    Science.gov (United States)

    Piao, Chunmei; Youn, Cha-Kyung; Jin, Min; Yoon, Sang Pil; Chang, In-Youb; Lee, Jung Hee; You, Ho Jin

    2012-09-01

    The p53R2 protein, a newly identified member of the ribonucleotide reductase family that provides nucleotides for DNA damage repair, is directly regulated by p53. We show that p53R2 is also regulated by a MEK2 (ERK kinase 2/MAP kinase kinase 2)-dependent pathway. Increased MEK1/2 phosphorylation by serum stimulation coincided with an increase in the RNR activity in U2OS and H1299 cells. The inhibition of MEK2 activity, either by treatment with a MEK inhibitor or by transfection with MEK2 siRNA, dramatically decreased the serum-stimulated RNR activity. Moreover, p53R2 siRNA, but not R2 siRNA, significantly inhibits serum-stimulated RNR activity, indicating that p53R2 is specifically regulated by a MEK2-dependent pathway. Co-immunoprecipitation analyses revealed that the MEK2 segment comprising amino acids 65-171 is critical for p53R2-MEK2 interaction, and the binding domain of MEK2 is required for MEK2-mediated increased RNR activity. Phosphorylation of MEK1/2 was greatly augmented by ionizing radiation, and RNR activity was concurrently increased. Ionizing radiation-induced RNR activity was markedly attenuated by transfection of MEK2 or p53R2 siRNA, but not R2 siRNA. These data show that MEK2 is an endogenous regulator of p53R2 and suggest that MEK2 may associate with p53R2 and upregulate its activity. PMID:22895183

  19. Respiratory Depression Caused by Heroin Use

    Directory of Open Access Journals (Sweden)

    Kadir Hakan Cansiz

    2012-04-01

    Full Text Available Summary Heroin is a semisynthetic narcotic analgesic and heroin abuse is common due to its pleasure-inducing effect. For the last 30 years heroin abuse has become an important worldwide public health problem. Heroin can be administered in many different ways as preferred. Heroin affects many systems including respiratory system, cardiovascular system and particulary the central nervous system. Overdose use of heroin intravenously can be fatal due to respiratory depression. In this letter, we wanted to engage attention to respiratory depression caused by heroin abuse and potential benefits of using naloxone. [TAF Prev Med Bull 2012; 11(2.000: 248-250

  20. Respiratory Disease: Diagnostic Approaches in the Horse.

    Science.gov (United States)

    Hewson, Joanne; Arroyo, Luis G

    2015-08-01

    Evaluation of the upper and lower respiratory tract of horses requires strategic selection of possible diagnostic tests based on location of suspected pathologic lesions and purpose of testing and must also include consideration of patient status. This article discusses the various diagnostic modalities that may be applied to the respiratory system of horses under field conditions, indications for use, and aspects of sample collection, handling, and laboratory processing that can impact test results and ultimately a successful diagnosis in cases of respiratory disease. PMID:26037608

  1. Discovery and characterization of a xylose reductase from Zymomonas mobilis ZM4.

    Science.gov (United States)

    Agrawal, Manoj; Chen, Rachel Ruizhen

    2011-11-01

    Formation of xylitol, a byproduct from xylose fermentation, is a major limiting factor in ethanol production from xylose in engineered Zymomonas strains, yet the postulated xylose reductase remains elusive. We report here the discovery of xylose reductase in Zymomonas mobilis and, for the first time, to associate the enzyme function with its gene. Besides xylose and xylulose, the enzyme was active towards benzaldehyde, furfural, 5-hydroxymethyl furfural, and acetaldehyde, exhibiting nearly 150-times higher affinity with benzaldehyde than xylose. The discovery of xylose reductase paves the way for further improvement of xylose fermentation in Z. mobilis. The enzyme may also be used to mitigate toxicity of furfural and other inhibitors from plant biomass. PMID:21720846

  2. Crystallization and preliminary X-ray diffraction analysis of maize aldose reductase

    Energy Technology Data Exchange (ETDEWEB)

    Kiyota, Eduardo [Laboratório de Biologia Estrutural, Instituto de Química, Universidade Estadual de Campinas, CP 6154, 13083-970 Campinas-SP (Brazil); Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas-SP (Brazil); Sousa, Sylvia Morais de [Centro de Biologia Molecular e Engenharia Genética, Universidade Estadual de Campinas, Campinas-SP (Brazil); Santos, Marcelo Leite dos; Costa Lima, Aline da [Laboratório de Biologia Estrutural, Instituto de Química, Universidade Estadual de Campinas, CP 6154, 13083-970 Campinas-SP (Brazil); Menossi, Marcelo [Departamento de Genética e Evolução, Instituto de Biologia, Universidade Estadual de Campinas, Campinas-SP (Brazil); Yunes, José Andrés [Laboratório de Biologia Molecular, Centro Infantil Boldrini, Campinas-SP (Brazil); Aparicio, Ricardo, E-mail: aparicio@iqm.unicamp.br [Laboratório de Biologia Estrutural, Instituto de Química, Universidade Estadual de Campinas, CP 6154, 13083-970 Campinas-SP (Brazil)

    2007-11-01

    Preliminary X-ray diffraction studies of apo maize aldose reductase at 2.0 Å resolution are reported. Maize aldose reductase (AR) is a member of the aldo-keto reductase superfamily. In contrast to human AR, maize AR seems to prefer the conversion of sorbitol into glucose. The apoenzyme was crystallized in space group P2{sub 1}2{sub 1}2{sub 1}, with unit-cell parameters a = 47.2, b = 54.5, c = 100.6 Å and one molecule in the asymmetric unit. Synchrotron X-ray diffraction data were collected and a final resolution limit of 2.0 Å was obtained after data reduction. Phasing was carried out by an automated molecular-replacement procedure and structural refinement is currently in progress. The refined structure is expected to shed light on the functional/enzymatic mechanism and the unusual activities of maize AR.

  3. Biochemical predetermination of the NO synthase and nitrite reductase components of the nitric oxide cycle.

    Science.gov (United States)

    Reutov, V P

    1999-05-01

    This review presents some aspects of a concept of cellular evolution bearing a relationship to nitrate--nitrite respiration, the endosymbiosis theory, and the origin of NO synthase and nitrite reductase activity in heme-containing proteins. Analysis of structural and functional unity of the NO synthase and nitrite reductase systems suggests that these systems did not arise without any relation to evolutionarily ancient energetic systems of cells. The use of symmetry principles reveals commonalities among many electron transport chains which in the language of physics is called "invariance". This work also comparatively analyzes the nitric oxide cycle and the known nitrogen cycle. The ideas about evolution of the NO synthase and nitrite reductase systems developed here are clearly compatible with the endosymbiotic theory and the hypothesis that nitrate--nitrite respiration was a precursor of oxygen-dependent respiration. PMID:10381613

  4. Crystallization and preliminary X-ray crystallographic studies of pig heart carbonyl reductase

    International Nuclear Information System (INIS)

    Pig heart carbonyl reductase has been crystallized in the presence of NADPH. Diffraction data have been collected using synchrotron radiation. Pig heart carbonyl reductase (PHCR), which belongs to the short-chain dehydrogenase/reductase (SDR) family, has been crystallized by the hanging-drop vapour-diffusion method. Two crystal forms (I and II) have been obtained in the presence of NADPH. Form I crystals belong to the tetragonal space group P42, with unit-cell parameters a = b = 109.61, c = 94.31 Å, and diffract to 1.5 Å resolution. Form II crystals belong to the tetragonal space group P41212, with unit-cell parameters a = b = 120.10, c = 147.00 Å, and diffract to 2.2 Å resolution. Both crystal forms are suitable for X-ray structure analysis at high resolution

  5. Synthetic and Crystallographic Studies of a New Inhibitor Series Targeting Bacillus anthracis Dihydrofolate Reductase

    Energy Technology Data Exchange (ETDEWEB)

    Beierlein, J.; Frey, K; Bolstad, D; Pelphrey, P; Joska, T; Smith, A; Priestley, N; Wright, D; Anderson, A

    2008-01-01

    Bacillus anthracis, the causative agent of anthrax, poses a significant biodefense danger. Serious limitations in approved therapeutics and the generation of resistance have produced a compelling need for new therapeutic agents against this organism. Bacillus anthracis is known to be insensitive to the clinically used antifolate, trimethoprim, because of a lack of potency against the dihydrofolate reductase enzyme. Herein, we describe a novel lead series of B. anthracis dihydrofolate reductase inhibitors characterized by an extended trimethoprim-like scaffold. The best lead compound adds only 22 Da to the molecular weight and is 82-fold more potent than trimethoprim. An X-ray crystal structure of this lead compound bound to B. anthracis dihydrofolate reductase in the presence of NADPH was determined to 2.25 A resolution. The structure reveals several features that can be exploited for further development of this lead series.

  6. Crystallization and preliminary X-ray diffraction analysis of maize aldose reductase

    International Nuclear Information System (INIS)

    Preliminary X-ray diffraction studies of apo maize aldose reductase at 2.0 Å resolution are reported. Maize aldose reductase (AR) is a member of the aldo-keto reductase superfamily. In contrast to human AR, maize AR seems to prefer the conversion of sorbitol into glucose. The apoenzyme was crystallized in space group P212121, with unit-cell parameters a = 47.2, b = 54.5, c = 100.6 Å and one molecule in the asymmetric unit. Synchrotron X-ray diffraction data were collected and a final resolution limit of 2.0 Å was obtained after data reduction. Phasing was carried out by an automated molecular-replacement procedure and structural refinement is currently in progress. The refined structure is expected to shed light on the functional/enzymatic mechanism and the unusual activities of maize AR

  7. Alpha 1-blockers vs 5 alpha-reductase inhibitors in benign prostatic hyperplasia. A comparative review

    DEFF Research Database (Denmark)

    Andersen, J T

    1995-01-01

    During recent years, pharmacological treatment of symptomatic benign prostatic hyperplasia (BPH) has become the primary treatment choice for an increasing number of patients. The 2 principal drug classes employed are alpha 1-blockers and 5 alpha-reductase inhibitors. Current information from...... patients who will respond well to alpha 1-blockers have yet to be identified, and data concerning the long term effects of these drugs are not yet available. 5 alpha-Reductase inhibitors have a slow onset of effect, but treatment leads to improvement in symptoms, reduction of the size of the prostate gland...... and improvement in objective parameters for bladder outflow obstruction. Approximately 30 to 50% of patients will respond to treatment with 5 alpha-reductase inhibitors. The definitive role of pharmacological treatment in symptomatic BPH remains to be established, although it seems that patients unfit...

  8. BIOLOGICAL ROLE OF ALDO-KETO REDUCTASES IN RETINOIC ACID BIOSYNTHESIS AND SIGNALING

    Directory of Open Access Journals (Sweden)

    F. Xavier eRuiz

    2012-04-01

    Full Text Available Several aldo-keto reductase (AKR enzymes from subfamilies 1B and 1C show retinaldehyde reductase activity, having low Km and kcat values. Only AKR1B10 and 1B12, with all-trans-retinaldehyde, and AKR1C3, with 9-cis-retinaldehyde, display high catalytic efficiency. Major structural determinants for retinaldehyde isomer specificity are located in the external loops (A and C for AKR1B10, and B for AKR1C3, as assessed by site-directed mutagenesis and molecular dynamics. Cellular models have shown that AKR1B and 1C enzymes are well suited to work in vivo as retinaldehyde reductases and to regulate retinoic acid (RA biosynthesis at hormone pre-receptor level. An additional physiological role for the retinaldehyde reductase activity of these enzymes, consistent with their tissue localization, is their participation in β-carotene absorption. Retinaldehyde metabolism may be subjected to subcellular compartmentalization, based on enzyme localization. While retinaldehyde oxidation to RA takes place in the cytosol, reduction to retinol could take place in the cytosol by AKRs or in the membranes of endoplasmic reticulum by microsomal retinaldehyde reductases. Upregulation of some AKR1 enzymes in different cancer types may be linked to their induction by oxidative stress and to their participation in different signaling pathways related to cell proliferation. AKR1B10 and AKR1C3, through their retinaldehyde reductase activity, trigger a decrease in the RA biosynthesis flow, resulting in RA deprivation and consequently lower differentiation, with an increased cancer risk in target tissues. Rational design of selective AKR inhibitors could lead to development of novel drugs for cancer treatment as well as reduction of chemotherapeutic drug resistance.

  9. Putative Role of the Aldo-Keto Reductase from Trypanosoma cruzi in Benznidazole Metabolism.

    Science.gov (United States)

    Garavaglia, Patricia Andrea; Laverrière, Marc; Cannata, Joaquín J B; García, Gabriela Andrea

    2016-05-01

    Benznidazole (Bz), the drug used for treatment of Chagas' disease (caused by the protozoan Trypanosoma cruzi), is activated by a parasitic NADH-dependent type I nitroreductase (NTR I). However, several studies have shown that other enzymes are involved. The aim of this study was to evaluate whether the aldo-keto reductase from T. cruzi (TcAKR), a NADPH-dependent oxido-reductase previously described by our group, uses Bz as the substrate. We demonstrated that both recombinant and native TcAKR enzymes reduce Bz by using NADPH, but not NADH, as a cofactor. TcAKR-overexpressing epimastigotes showed higher NADPH-dependent Bz reductase activity and a 50% inhibitory concentration (IC50) value for Bz 1.8-fold higher than that of the controls, suggesting that TcAKR is involved in Bz detoxification instead of activation. To understand the role of TcAKR in Bz metabolism, we studied TcAKR expression and NADPH/NADH-dependent Bz reductase activities in two T. cruzi strains with differential susceptibility to Bz: CL Brener and Nicaragua. Taking into account the results obtained with TcAKR-overexpressing epimastigotes, we expected the more resistant strain, Nicaragua, to have higher TcAKR levels than CL Brener. However, the results were the opposite. CL Brener showed 2-fold higher TcAKR expression and 5.7-fold higher NADPH-Bz reduction than the Nicaragua strain. In addition, NADH-dependent Bz reductase activity, characteristic of NTR I, was also higher in CL Brener than in Nicaragua. We conclude that although TcAKR uses Bz as the substrate, TcAKR activity is not a determinant of Bz resistance in wild-type strains and may be overcome by other enzymes involved in Bz activation, such as NADPH- and NADH-dependent reductases. PMID:26856844

  10. Characterisation of a desmosterol reductase involved in phytosterol dealkylation in the silkworm, Bombyx mori.

    Directory of Open Access Journals (Sweden)

    Leonora F Ciufo

    Full Text Available Most species of invertebrate animals cannot synthesise sterols de novo and many that feed on plants dealkylate phytosterols (mostly C(29 and C(28 yielding cholesterol (C(27. The final step of this dealkylation pathway involves desmosterol reductase (DHCR24-catalysed reduction of desmosterol to cholesterol. We now report the molecular characterisation in the silkworm, Bombyx mori, of such a desmosterol reductase involved in production of cholesterol from phytosterol, rather than in de novo synthesis of cholesterol. Phylogenomic analysis of putative desmosterol reductases revealed the occurrence of various clades that allowed for the identification of a strong reductase candidate gene in Bombyx mori (BGIBMGA 005735. Following PCR-based cloning of the cDNA (1.6 kb and its heterologous expression in Saccharomyces cerevisae, the recombinant protein catalysed reduction of desmosterol to cholesterol in an NADH- and FAD-dependent reaction.Conceptual translation of the cDNA, that encodes a 58.9 kDa protein, and database searching, revealed that the enzyme belongs to an FAD-dependent oxidoreductase family. Western blotting revealed reductase protein expression exclusively in the microsomal subcellular fraction and primarily in the gut. The protein is peripherally associated with microsomal membranes. 2D-native gel and PAGE analysis revealed that the reductase is part of a large complex with molecular weight approximately 250 kDa. The protein occurs in midgut microsomes at a fairly constant level throughout development in the last two instars, but is drastically reduced during the wandering stage in preparation for metamorphosis. Putative Broad Complex transcription factor-binding sites detectable upstream of the DHCR24 gene may play a role in this down-regulation.

  11. Chaotic dynamics of respiratory sounds

    International Nuclear Information System (INIS)

    There is a growing interest in nonlinear analysis of respiratory sounds (RS), but little has been done to justify the use of nonlinear tools on such data. The aim of this paper is to investigate the stationarity, linearity and chaotic dynamics of recorded RS. Two independent data sets from 8 + 8 healthy subjects were recorded and investigated. The first set consisted of lung sounds (LS) recorded with an electronic stethoscope and the other of tracheal sounds (TS) recorded with a contact accelerometer. Recurrence plot analysis revealed that both LS and TS are quasistationary, with the parts corresponding to inspiratory and expiratory flow plateaus being stationary. Surrogate data tests could not provide statistically sufficient evidence regarding the nonlinearity of the data. The null hypothesis could not be rejected in 4 out of 32 LS cases and in 15 out of 32 TS cases. However, the Lyapunov spectra, the correlation dimension (D 2) and the Kaplan-Yorke dimension (D KY) all indicate chaotic behavior. The Lyapunov analysis showed that the sum of the exponents was negative in all cases and that the largest exponent was found to be positive. The results are partly ambiguous, but provide some evidence of chaotic dynamics of RS, both concerning LS and TS. The results motivate continuous use of nonlinear tools for analysing RS data

  12. Chaotic dynamics of respiratory sounds

    Energy Technology Data Exchange (ETDEWEB)

    Ahlstrom, C. [Department of Biomedical Engineering, Linkoepings Universitet, IMT/LIU, Universitetssjukhuset, S-58185 Linkoeping (Sweden) and Biomedical Engineering, Orebro University Hospital, S-70185 Orebro (Sweden)]. E-mail: christer@imt.liu.se; Johansson, A. [Department of Biomedical Engineering, Linkoepings Universitet, IMT/LIU, Universitetssjukhuset, S-58185 Linkoeping (Sweden); Hult, P. [Department of Biomedical Engineering, Linkoepings Universitet, IMT/LIU, Universitetssjukhuset, S-58185 Linkoeping (Sweden); Biomedical Engineering, Orebro University Hospital, S-70185 Orebro (Sweden); Ask, P. [Department of Biomedical Engineering, Linkoepings Universitet, IMT/LIU, Universitetssjukhuset, S-58185 Linkoeping (Sweden); Biomedical Engineering, Orebro University Hospital, S-70185 Orebro (Sweden)

    2006-09-15

    There is a growing interest in nonlinear analysis of respiratory sounds (RS), but little has been done to justify the use of nonlinear tools on such data. The aim of this paper is to investigate the stationarity, linearity and chaotic dynamics of recorded RS. Two independent data sets from 8 + 8 healthy subjects were recorded and investigated. The first set consisted of lung sounds (LS) recorded with an electronic stethoscope and the other of tracheal sounds (TS) recorded with a contact accelerometer. Recurrence plot analysis revealed that both LS and TS are quasistationary, with the parts corresponding to inspiratory and expiratory flow plateaus being stationary. Surrogate data tests could not provide statistically sufficient evidence regarding the nonlinearity of the data. The null hypothesis could not be rejected in 4 out of 32 LS cases and in 15 out of 32 TS cases. However, the Lyapunov spectra, the correlation dimension (D {sub 2}) and the Kaplan-Yorke dimension (D {sub KY}) all indicate chaotic behavior. The Lyapunov analysis showed that the sum of the exponents was negative in all cases and that the largest exponent was found to be positive. The results are partly ambiguous, but provide some evidence of chaotic dynamics of RS, both concerning LS and TS. The results motivate continuous use of nonlinear tools for analysing RS data.

  13. Sexual intercourse and respiratory failure.

    Science.gov (United States)

    Polverino, Francesca; Santoriello, Carlo; De Sio, Vittorio; Andò, Filippo; de Blasio, Francesco; Polverino, Mario

    2008-06-01

    Sexual activity is an important component of quality of life in patients suffering from chronic illnesses. To our knowledge, the effects of sexual activity on gas exchange in patients with respiratory failure have not been yet studied. To such an extent, we evaluated the oxygen saturation (SaO2), by a pulse oxymeter, during three different sexual performances in a 63-yr-old patient affected by chronic obstructive pulmonary disease (COPD) on long-term oxygen therapy (LTOT). The sexual performances were divided in four periods: basal, sex, 10 min after sex and relax. In each performance during sex, we observed a significant increase of either heart rate (HR) or SaO2, with the highest value of the latter achieved within the 10 min of the post-sex period. SaO2 returned to basal value (pre-sex) by the end of the relax period. We conclude that the observed improvement of SaO2 during sexual activity might be due to a better ventilation/perfusion ratio (V/Q) obtained for either an increase of ventilation (hyperventilation) and perfusion (tachycardia), without significant muscle expenditure. PMID:18394872

  14. [Respiratory mechanics in professional flautists].

    Science.gov (United States)

    Cossette, I

    2002-04-01

    Oesophageal, gastric, mouth, transdiaphragmatic, transpulmonary pressures, diaphragmatic EMG, sound and chest wall excursion were measured directly in 3 professional flautists whilst playing their instruments to determine: - what respiratory muscles and percent vital capacity were being used; - how mouth pressure, embouchure resistance, embouchure aperture, airflow and velocity affect sound loudness and frequency. Lung volume was estimated from transpulmonary pressure during playing and the static deflation pressure-volume curve was measured separately; flow was calculated from delta volume/delta time; embouchure resistance was calculated from mouth pressure/flow; velocity was calculated using Bernouilli's equation and mouth pressure. Staccati and sustained tones at different frequency and intensity were performed. Sound loudness was mainly related to airflow whilst sound frequency was determined by velocity. Flow and velocity were independently controlled by mouth pressure and embouchure aperture. Mean mouth pressures varied little from individual to an other (6-11 cm H(2)O) but the flautists used between 72-83% of their vital capacity suggesting inspiratory muscle activity while playing. However, rib cage and abdominal motion were different for each subject. Although different flautists use different strategies to control mouth pressure, their individual mastery of the instrument permits control of airflow and velocity to produce the desired intensity and frequency of sound. PMID:12040320

  15. Aldose reductase inhibition prevents metaplasia of airway epithelial cells.

    Directory of Open Access Journals (Sweden)

    Umesh C S Yadav

    Full Text Available BACKGROUND: Goblet cell metaplasia that causes mucus hypersecretion and obstruction in the airway lumen could be life threatening in asthma and chronic obstructive pulmonary disease patients. Inflammatory cytokines such as IL-13 mediate the transformation of airway ciliary epithelial cells to mucin-secreting goblet cells in acute as well as chronic airway inflammatory diseases. However, no effective and specific pharmacologic treatment is currently available. Here, we investigated the mechanisms by which aldose reductase (AR regulates the mucus cell metaplasia in vitro and in vivo. METHODOLOGY/FINDINGS: Metaplasia in primary human small airway epithelial cells (SAEC was induced by a Th2 cytokine, IL-13, without or with AR inhibitor, fidarestat. After 48 h of incubation with IL-13 a large number of SAEC were transformed into goblet cells as determined by periodic acid-schiff (PAS-staining and immunohistochemistry using antibodies against Mucin5AC. Further, IL-13 significantly increased the expression of Mucin5AC at mRNA and protein levels. These changes were significantly prevented by treatment of the SAEC with AR inhibitor. AR inhibition also decreased IL-13-induced expression of Muc5AC, Muc5B, and SPDEF, and phosphorylation of JAK-1, ERK1/2 and STAT-6. In a mouse model of ragweed pollen extract (RWE-induced allergic asthma treatment with fidarestat prevented the expression of IL-13, phosphorylation of STAT-6 and transformation of epithelial cells to goblet cells in the lung. Additionally, while the AR-null mice were resistant, wild-type mice showed goblet cell metaplasia after challenge with RWE. CONCLUSIONS: The results show that exposure of SAEC to IL-13 caused goblet cell metaplasia, which was significantly prevented by AR inhibition. Administration of fidarestat to mice prevented RWE-induced goblet cell metaplasia and AR null mice were largely resistant to allergen induced changes in the lung. Thus our results indicate that AR inhibitors

  16. GENERATION OF THE GLYCYL RADICAL OF THE ANAEROBIC ESCHERICHIA-COLI RIBONUCLEOTIDE REDUCTASE REQUIRES A SPECIFIC ACTIVATING ENZYME

    NARCIS (Netherlands)

    SUN, XY; ELIASSON, R; PONTIS, E; ANDERSSON, J; BUIST, G; SJOBERG, BM; REICHARD, P

    1995-01-01

    The anaerobic ribonucleotide reductase from Escherichia coli contains a glycyl radical as part of its polypeptide structure. The radical is generated by an enzyme system present in E. coli. The reductase is coded for by the nrdD gene located at 96 min. Immediately downstream, we now find an open rea

  17. Direct enzyme assay evidence confirms aldehyde reductase function of Ydr541cp and Ygl039wp from Saccharomyces cerevisiae

    Science.gov (United States)

    Aldehyde reductase gene ARI1 is a recently characterized member of intermediate subfamily under SDR (short-chain dehydrogenase/reductase) superfamily that revealed mechanisms of in situ detoxification of furfural and HMF for tolerance of Saccharomyces cerevisiae. Uncharacterized open reading frames ...

  18. Feedback regulation of cholesterol synthesis:sterol-accelerated ubiquitination and degradation of HMG CoA reductase

    Institute of Scientific and Technical Information of China (English)

    Russell A DeBose-Boyd

    2008-01-01

    3Hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase produces mevalonate,an important intermediate in the synthesis of cholesterol and essential nonsterol isoprenoids.The reductase is subject to an exorbitant amount of feedback control through multiple mechanisms that are mediated by sterol and nonsterol end-products of mevalonate metabolism.Here,Ⅰwill discuss recent advances that shed light on one mechanism for control of reductase,which involves rapid degradation of the enzyme.Accumulation of certain sterols triggers binding of reductase to endoplasmic reticulum (ER) membrane proteins called Insig-1 and Insig-2.Reductase-Insig binding results in recruitment of a membrane-associated ubiquitin ligase called gp78,which initiates ubiquitination of reductase.This ubiquitination is an obligatory reaction for recognition and degradation of reductase from ER membranes by cytosolic 26S proteasomes.Thus,sterol-accelerated degradation of reductase represents an example of how a general cellular process (ER-associated degradation) is used to control an important metabolic pathway (cholesterol synthesis).

  19. Multiple Types of 8-Vinyl Reductases for (Bacterio)Chlorophyll Biosynthesis Occur in Many Green Sulfur Bacteria ▿

    OpenAIRE

    Liu, Zhenfeng; Bryant, Donald A.

    2011-01-01

    Two 8-vinyl reductases, BciA and BciB, have been identified in chlorophototrophs. The bciA gene of Chlorobaculum tepidum was replaced with genes similar to bciB from other green sulfur bacteria. Pigment analyses of the complemented strains showed that the bciB homologs encode 8-vinyl reductases similar to those of cyanobacteria.

  20. Studies on some characteristics of nitrate reductase from sugar beet (Beta vulgaris L.)leaves

    Institute of Scientific and Technical Information of China (English)

    LiWenhua; YanGuiping; 等

    1994-01-01

    Some characteristics of nitrate reductase from sugar beet leaves shown in this paper were as follows:The nitrate reductase from sugar beet leaves required NADH as an electron donor.Accordingly,the nitrate reductase was classified as NADH-dependent(E.C.1.6.61).The Km value of the nitrate reductase for NADH and NO3- were 0.86m mol and 0.18μ mol respectively.The optimum pH in reaction mixture solution for nitrate reduction activity was 7.5.The effect of variable concentrations of inorganic phosphorus in the reaction buffer on nitrate reductase activity was investigated.When the inorganic phosphorus concentration was below 35m mol,the nitrate reductase activity was increased with increase of inorganic phosphorus concentration.Conversely,when the inorganic phosphorus concentration was over 35m mol,the nitrate reductase activity was inhibited.The nitrate reductase activity assayed in vitro was 3.2 and 5.6times of that assayed in vivo under the condition of exogenous and endogenous ground substance respectively.

  1. The role of 5'-adenylylsulfate reductase in the sulfur assimilation pathway of soybean: molecular cloning, kinetic characterization, and gene expression

    Science.gov (United States)

    Soybean seeds are a major source of protein, but contain low levels of sulfur-containing amino acids. With the objective of studying the sulfur assimilation pathway of soybean, a full-length cDNA clone for 5’-adenylylsulfate reductase (APS reductase) was isolated and characterized. The cDNA clone ...

  2. Inverse relationship between age-dependent erythrocyte activity of methaemoglobin reductase and prilocaine-induced methaemoglobinaemia during infancy

    DEFF Research Database (Denmark)

    Nilsson, A; Engberg, G; Henneberg, S; Danielson, K; De Verdier, C H

    1990-01-01

    concentrations of local anaesthetics were low (maximum values: prilocaine 78 ng ml-1, lignocaine 412 ng ml-1). The activity of erythrocyte MetHb reductase (cytochrome b5 reductase) was analysed. Data from a previously studied group of infants aged 3-12 months were included also. Enzyme activity did not reach...

  3. Identification of the bchP gene, encoding geranylgeranyl reductase in Chlorobaculum tepidum

    DEFF Research Database (Denmark)

    Gomez Maqueo Chew, Aline; Frigaard, Niels-Ulrik; Bryant, Donald A

    2008-01-01

    The Chlorobaculum tepidum genome contains two paralogous genes, CT2256 and CT1232, whose products are members of the FixC dehydrogenase superfamily and have sequence similarity to geranylgeranyl reductases. Each gene was insertionally inactivated, and the resulting mutants were characterized. CT2......2256 encodes geranylgeranyl reductase (BchP); CT1232 is not involved in bacteriochlorophyll or chlorophyll biosynthesis....

  4. Synthesis and degradation of nitrate reductase during the cell cycle of Chlorella sorokiniana

    Science.gov (United States)

    Velasco, P. J.; Tischner, R.; Huffaker, R. C.; Whitaker, J. R.

    1989-01-01

    Studies on the diurnal variations of nitrate reductase (NR) activity during the life cycle of synchronized Chlorella sorokiniana cells grown with a 7:5 light-dark cycle showed that the NADH:NR activity, as well as the NR partial activities NADH:cytochrome c reductase and reduced methyl viologen:NR, closely paralleled the appearance and disappearance of NR protein as shown by sodium dodecyl sulfate gel electrophoresis and immunoblots. Results of pulse-labeling experiments with [35S]methionine further confirmed that diurnal variations of the enzyme activities can be entirely accounted for by the concomitant synthesis and degradation of the NR protein.

  5. Affinity purifications of aldose reductase and xylitol dehydrogenase from the xylose-fermenting yeast Pachysolen tannophilus

    Energy Technology Data Exchange (ETDEWEB)

    Bolen, P.L.; Roth, K.A.; Freer, S.N.

    1986-10-01

    Although xylose is a major product of hydrolysis of lignocellulosic materials, few yeasts are able to convert it to ethanol. In Pachysolen tannophilus, one of the few xylose-fermenting yeasts found, aldose reductase and xylitol dehydrogenase were found to be key enzymes in the metabolic pathway for xylose fermentation. This paper presents a method for the rapid and simultaneous purification of both aldose reductase and xylitol dehydrogenase from P. tannophilus. Preliminary studies indicate that this method may be easily adapted to purify similar enzymes from other xylose-fermenting yeasts.

  6. Glyphosate inhibition of ferric reductase activity in iron deficient sunflower roots

    OpenAIRE

    Öztürk, Levent; Ozturk, Levent; Yazıcı, Mustafa Atilla; Yazici, Mustafa Atilla; Eker, Selim; Gökmen, Özay Özgür; Gokmen, Ozay Ozgur; Römheld, Volker; Romheld, Volker; ÇAKMAK, İsmail; Cakmak, Ismail

    2007-01-01

    Iron (Fe) deficiency is increasingly being observed in cropping systems with frequent glyphosate applications. A likely reason for this is that glyphosate interferes with root uptake of Fe by inhibiting ferric reductase in roots required for Fe acquisition by dicot and nongrass species. This study investigated the role of drift rates of glyphosate (0.32, 0.95 or 1.89 mM glyphosate corresponding to 1, 3 and 6% of the recommended herbicidal dose, respectively) on ferric reductase activity of...

  7. Mutational analysis of the nor gene cluster which encodes nitric-oxide reductase from Paracoccus denitrificans.

    Science.gov (United States)

    de Boer, A P; van der Oost, J; Reijnders, W N; Westerhoff, H V; Stouthamer, A H; van Spanning, R J

    1996-12-15

    The genes that encode the hc-type nitric-oxide reductase from Paracoccus denitrificans have been identified. They are part of a cluster of six genes (norCBQDEF) and are found near the gene cluster that encodes the cd1-type nitrite reductase, which was identified earlier [de Boer, A. P. N., Reijnders, W. N. M., Kuenen, J. G., Stouthamer, A. H. & van Spanning, R. J. M. (1994) Isolation, sequencing and mutational analysis of a gene cluster involved in nitrite reduction in Paracoccus denitrificans, Antonie Leeu wenhoek 66, 111-127]. norC and norB encode the cytochrome-c-containing subunit II and cytochrome b-containing subunit I of nitric-oxide reductase (NO reductase), respectively. norQ encodes a protein with an ATP-binding motif and has high similarity to NirQ from Pseudomonas stutzeri and Pseudomonas aeruginosa and CbbQ from Pseudomonas hydrogenothermophila. norE encodes a protein with five putative transmembrane alpha-helices and has similarity to CoxIII, the third subunit of the aa3-type cytochrome-c oxidases. norF encodes a small protein with two putative transmembrane alpha-helices. Mutagenesis of norC, norB, norQ and norD resulted in cells unable to grow anaerobically. Nitrite reductase and NO reductase (with succinate or ascorbate as substrates) and nitrous oxide reductase (with succinate as substrate) activities were not detected in these mutant strains. Nitrite extrusion was detected in the medium, indicating that nitrate reductase was active. The norQ and norD mutant strains retained about 16% and 23% of the wild-type level of NorC, respectively. The norE and norF mutant strains had specific growth rates and NorC contents similar to those of the wild-type strain, but had reduced NOR and NIR activities, indicating that their gene products are involved in regulation of enzyme activity. Mutant strains containing the norCBQDEF region on the broad-host-range vector pEG400 were able to grow anaerobically, although at a lower specific growth rate and with lower

  8. Properties of a Thermostable Nitrate Reductase from the Hyperthermophilic Archaeon Pyrobaculum aerophilum

    OpenAIRE

    Afshar, Sepideh; Johnson, Eric; de Vries, Simon; Schröder, Imke

    2001-01-01

    The nitrate reductase of the hyperthermophilic archaeon Pyrobaculum aerophilum was purified 137-fold from the cytoplasmic membrane. Based on sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis, the enzyme complex consists of three subunits with apparent molecular weights of 130,000, 52,000, and 32,000. The enzyme contained molybdenum (0.8-mol/mol complex), iron (15.4-mol/mol complex) and cytochrome b (0.49-mol/mol complex) as cofactors. The P. aerophilum nitrate reductase disti...

  9. Imaging the activity of nitrate reductase by means of a scanning electrochemical microscope.

    Science.gov (United States)

    Zaumseil, J; Wittstock, G; Bahrs, S; Steinrücke, P

    2000-06-01

    Scanning electrochemical microscopy (SECM) was used to characterize immobilized nitrate reductase (NaR) from Pseudonomonas stutzeri (E.C. 1.7.99.4). Nitrate reductase with membrane fragment was embedded in a polyurethane hydrogel in a capillary and solubilized NaR without membrane fragment was covalently coupled to a diaminoethyl-cellulose-carbamitate film on glass. After systematic studies of possible mediators, SECM feedback imaging of both forms of immobilized NaR was accomplished with methylviologen as redox mediator. PMID:11225859

  10. Crystallization and preliminary X-ray diffraction studies of ferredoxin reductase from Leptospira interrogans

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Alessandro S.; Ferrarezi, Thiago [Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador Saocarlense 400, São Carlos, SP, 13560-970 (Brazil); Catalano-Dupuy, Daniela L.; Ceccarelli, Eduardo A. [Facultad de Ciencias Bioquímicas y Farmacéuticas, Molecular Biology Division, Instituto de Biología Molecular y Celular de Rosario (IBR), CONICET, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario (Argentina); Polikarpov, Igor, E-mail: ipolikarpov@if.sc.usp.br [Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador Saocarlense 400, São Carlos, SP, 13560-970 (Brazil)

    2006-07-01

    Crystals adequate for X-ray diffraction analysis have been prepared from L. interrogans ferredoxin-NADP{sup +} reductase. Ferredoxin-NADP{sup +} reductase (FNR) is an FAD-containing enzyme that catalyzes electron transfer between NADP(H) and ferredoxin. Here, results are reported of the recombinant expression, purification and crystallization of FNR from Leptospira interrogans, a parasitic bacterium of animals and humans. The L. interrogans FNR crystals belong to a primitive monoclinic space group and diffract to 2.4 Å resolution at a synchrotron source.

  11. Crystallization and preliminary X-ray diffraction studies of ferredoxin reductase from Leptospira interrogans

    International Nuclear Information System (INIS)

    Crystals adequate for X-ray diffraction analysis have been prepared from L. interrogans ferredoxin-NADP+ reductase. Ferredoxin-NADP+ reductase (FNR) is an FAD-containing enzyme that catalyzes electron transfer between NADP(H) and ferredoxin. Here, results are reported of the recombinant expression, purification and crystallization of FNR from Leptospira interrogans, a parasitic bacterium of animals and humans. The L. interrogans FNR crystals belong to a primitive monoclinic space group and diffract to 2.4 Å resolution at a synchrotron source

  12. Cloning, Expression, and Purification of Histidine-Tagged Escherichia coli Dihydrodipicolinate Reductase

    OpenAIRE

    Trigoso, Yvonne D.; Russell C Evans; Karsten, William E.; Lilian Chooback

    2016-01-01

    The enzyme dihydrodipicolinate reductase (DHDPR) is a component of the lysine biosynthetic pathway in bacteria and higher plants. DHDPR catalyzes the NAD(P)H dependent reduction of 2,3-dihydrodipicolinate to the cyclic imine L-2,3,4,5,-tetrahydropicolinic acid. The dapB gene that encodes dihydrodipicolinate reductase has previously been cloned, but the expression of the enzyme is low and the purification is time consuming. Therefore the E. coli dapB gene was cloned into the pET16b vector to i...

  13. RESPIRATORY SYNCYTIAL VIRUS INFECTION AMONG YOUNG CHILDREN WITH ACUTE RESPIRATORY INFECTION

    OpenAIRE

    Milani, M

    2003-01-01

    Respiratory syncytial virus (RSV) is the major cause of lower respiratory tract infections in infants,and also an important factor for hospitalization during the winter months. To determine the prevalence and importance of RSV as a cause of acute lower respiratory tract infection, we carried out a prospective study during 5 months period from November to March 1998 in 6 pediatric hospitals. A nasopharyngeal aspirate was obtained for detection of RSV in all cases. Sociodemographic data, clinic...

  14. Efficient and Cost-effective Estimation of the Influence of Respiratory Variables on Respiratory Sinus Arrhythmia

    OpenAIRE

    Egizio, Victoria B.; Eddy, Michael; Robinson, Matthew; Jennings, J. Richard

    2010-01-01

    Researchers are interested in respiratory sinus arrhythmia (RSA) as an index of cardiac vagal activity. Yet, debate exists about how to account for respiratory influences on quantitative indices of RSA. Ritz and colleagues (2001) developed a within-individual correction procedure by which the effects of respiration on RSA may be estimated using regression models. We replicated their procedure substituting a spectral high-frequency measure of RSA for a time-domain statistic and a respiratory b...

  15. Diagnosis of influenza from lower respiratory tract sampling after negative upper respiratory tract sampling.

    Science.gov (United States)

    Bogoch, Isaac I; Andrews, Jason R; Zachary, Kimon C; Hohmann, Elizabeth L

    2013-01-01

    In this retrospective cohort study, we demonstrate that PCR-confirmed diagnoses of influenza were made solely by lower respiratory sampling in 6.9% of cases, as traditional upper respiratory tract tests were negative, indeterminate or not performed. Clinical features of these cases are presented. Clinicians should consider lower respiratory tract sampling in select cases of influenza-like illness for diagnosis. PMID:23135351

  16. Diagnosis of influenza from lower respiratory tract sampling after negative upper respiratory tract sampling

    Science.gov (United States)

    Bogoch, Isaac I.; Andrews, Jason R.; Zachary, Kimon C.; Hohmann, Elizabeth L.

    2013-01-01

    In this retrospective cohort study, we demonstrate that PCR-confirmed diagnoses of influenza were made solely by lower respiratory sampling in 6.9% of cases, as traditional upper respiratory tract tests were negative, indeterminate or not performed. Clinical features of these cases are presented. Clinicians should consider lower respiratory tract sampling in select cases of influenza-like illness for diagnosis. PMID:23135351

  17. Noninvasive Mechanical Ventilation in Acute Respiratory Failure Patients: A Respiratory Therapist Perspective

    OpenAIRE

    Hidalgo, V.; Giugliano-Jaramillo, C; Pérez, R.; Cerpa, F; Budini, H; Cáceres, D.; Gutiérrez, T.; Molina, J; Keymer, J; Romero-Dapueto, C

    2015-01-01

    Physiotherapist in Chile and Respiratory Therapist worldwide are the professionals who are experts in respiratory care, in mechanical ventilation (MV), pathophysiology and connection and disconnection criteria. They should be experts in every aspect of the acute respiratory failure and its management, they and are the ones who in medical units are able to resolve doubts about ventilation and the setting of the ventilator. Noninvasive mechanical ventilation should be the first-line of treatmen...

  18. Increased fatigue resistance of respiratory muscles during exercise after respiratory muscle endurance training

    OpenAIRE

    Verges, S; Lenherr, O; Haner, A C; Schulz, C.; Spengler, C M

    2007-01-01

    Respiratory muscle fatigue develops during exhaustive exercise and can limit exercise performance. Respiratory muscle training, in turn, can increase exercise performance. We investigated whether respiratory muscle endurance training (RMT) reduces exercise-induced inspiratory and expiratory muscle fatigue. Twenty-one healthy, male volunteers performed twenty 30-min sessions of either normocapnic hyperpnoea (n = 13) or sham training (CON, n = 8) over 4-5 wk. Before and after training, subjects...

  19. Respiratory system impedance from 4 to 40 Hz in paralyzed intubated infants with respiratory disease.

    OpenAIRE

    Dorkin, H L; Stark, A. R.; Werthammer, J W; Strieder, D J; Fredberg, J.J.; Frantz, I D

    1983-01-01

    To describe the mechanical characteristics of the respiratory system in intubated neonates with respiratory disease, we measured impedance and resistance in six paralyzed intubated infants with respiratory distress syndrome, three of whom also had pulmonary interstitial emphysema. We subtracted the effects of the endotracheal tube after showing that such subtraction was valid. Oscillatory flow was generated from 4 to 40 Hz by a loudspeaker, airway pressure was measured, and flow was calculate...

  20. Investigations of respiratory control systems simulation

    Science.gov (United States)

    Gallagher, R. R.

    1973-01-01

    The Grodins' respiratory control model was investigated and it was determined that the following modifications were necessary before the model would be adaptable for current research efforts: (1) the controller equation must be modified to allow for integration of the respiratory system model with other physiological systems; (2) the system must be more closely correlated to the salient physiological functionings; (3) the respiratory frequency and the heart rate should be expanded to illustrate other physiological relationships and dependencies; and (4) the model should be adapted to particular individuals through a better defined set of initial parameter values in addition to relating these parameter values to the desired environmental conditions. Several of Milhorn's respiratory control models were also investigated in hopes of using some of their features as modifications for Grodins' model.

  1. Respiratory acoustic impedance in left ventricular failure.

    Science.gov (United States)

    Depeursinge, F B; Feihl, F; Depeursinge, C; Perret, C H

    1989-12-01

    The measurement of respiratory acoustic impedance (Zrs) by forced pseudorandom noise provides a simple means of assessing respiratory mechanics in nonintubated intensive care patients. To characterize the lung mechanical alterations induced by acute vascular congestion of the lung, Zrs was measured in 14 spontaneously breathing patients hospitalized for acute left ventricular failure. The Zrs data in the cardiac patients were compared with those of 48 semirecumbent normal subjects and those of 23 sitting asthmatic patients during allergen-induced bronchospasm. In the patients with acute left ventricular failure, the Zrs abnormalities noted were an excessive frequency dependence of resistance from 10 to 20 Hz and an abnormally low reactance at all frequencies, abnormalities qualitatively similar to those observed in the asthmatic patients but of lesser magnitude. Acute lung vascular congestion modifies the acoustic impedance of the respiratory system. Reflex-induced bronchospasm might be the main mechanism altering respiratory acoustic impedance in acute left ventricular failure. PMID:2582846

  2. Retrotrapezoid nucleus, respiratory chemosensitivity and breathing automaticity

    Science.gov (United States)

    Guyenet, Patrice G.; Bayliss, Douglas A.; Stornetta, Ruth L.; Fortuna, Michal G.; Abbott, Stephen B.; Depuy, Seth D.

    2009-01-01

    SUMMARY Breathing automaticity and CO2 regulation are inseparable neural processes. The retrotrapezoid nucleus (RTN), a group of glutamatergic neurons that express the transcription factor Phox2b, may be a crucial nodal point through which breathing automaticity is regulated to maintain CO2 constant. This review updates the analysis presented in prior publications. Additional evidence that RTN neurons have central respiratory chemoreceptor properties is presented but this is only one of many factors that determine their activity. The RTN is also regulated by powerful inputs from the carotid bodies and, at least in the adult, by many other synaptic inputs. We also analyze how RTN neurons may control the activity of the downstream central respiratory pattern generator. Specifically, we review the evidence which suggests that RTN neurons a) innervate the entire ventral respiratory column, and b) control both inspiration and expiration. Finally, we argue that the RTN neurons are the adult form of the parafacial respiratory group in neonate rats. PMID:19712903

  3. National prevalence of respiratory allergic disorders

    NARCIS (Netherlands)

    Dahl, R; Andersen, PS; Chivato, T; Valovirta, E; De Monchy, J

    2004-01-01

    Background: Many epidemiological studies have assessed the prevalence of respiratory allergic disorders in confined geographical locations. However, no study has yet established nationally prevalence data in a uniform manner representing whole countries and, thus, enabling cross-national comparisons

  4. CAUSES OF RESPIRATORY DISTRESS IN CHILDREN

    Directory of Open Access Journals (Sweden)

    M M Karambin

    2008-11-01

    Full Text Available "nThere is a lack of large, prospective epidemiologic studies concerning acute lung injury (ALI and acute respiratory distress syndrome (ARDS in pediatric population. To determine the different causes of respiratory distress in children, we prepared a retrospective study and included the whole 567 children with respiratory distress referred to 17-Shahrivar Hospital, Rasht, Guilan. Using their medical files, data including age, sex, and causes of respiratory distress were collected. SPSS 13.0 (statistical software applied for statistical analysis. Pneumonia, asthma, and croup were the major causes of ARDS in children with a rate of 38.4, 19.04, and 16.5 percent, respectively. It seems that infectious factors are at the top of the list of ARDS causing factors which can be helpful to approach and manage such patients. We suggest vaccinating these at risk groups against common infectious factors such as H. Influenza and RSV which can cause either pneumonia or inducing asthma.

  5. Pinpointing a Mechanistic Switch Between Ketoreduction and “Ene” Reduction in Short‐Chain Dehydrogenases/Reductases

    Science.gov (United States)

    Lygidakis, Antonios; Karuppiah, Vijaykumar; Hoeven, Robin; Ní Cheallaigh, Aisling; Leys, David; Gardiner, John M.; Toogood, Helen S.

    2016-01-01

    Abstract Three enzymes of the Mentha essential oil biosynthetic pathway are highly homologous, namely the ketoreductases (−)‐menthone:(−)‐menthol reductase and (−)‐menthone:(+)‐neomenthol reductase, and the “ene” reductase isopiperitenone reductase. We identified a rare catalytic residue substitution in the last two, and performed comparative crystal structure analyses and residue‐swapping mutagenesis to investigate whether this determines the reaction outcome. The result was a complete loss of native activity and a switch between ene reduction and ketoreduction. This suggests the importance of a catalytic glutamate vs. tyrosine residue in determining the outcome of the reduction of α,β‐unsaturated alkenes, due to the substrate occupying different binding conformations, and possibly also to the relative acidities of the two residues. This simple switch in mechanism by a single amino acid substitution could potentially generate a large number of de novo ene reductases. PMID:27411040

  6. Isolation, modification, and aldose reductase inhibitory activity of rosmarinic acid derivatives from the roots of Salvia grandifolia.

    Science.gov (United States)

    Kang, Jie; Tang, Yanbo; Liu, Quan; Guo, Nan; Zhang, Jian; Xiao, Zhiyan; Chen, Ruoyun; Shen, Zhufang

    2016-07-01

    To find aldose reductase inhibitors, two previously unreported compounds, grandifolias H and I, and five known compounds, including rosmarinic acid and rosmarinic acid derivatives, were isolated from the roots of Salvia grandifolia. A series of rosmarinic acid derivatives was obtained from rosmarinic acid using simple synthetic methods. The aldose reductase inhibitory activity of the isolated and synthesized compounds was assessed. Seven of the tested compounds showed moderate aldose reductase inhibition (IC50=0.06-0.30μM). The structure-activity relationship of aldose reductase inhibitory activity of rosmarinic acid derivatives was discussed for the first time. This study provided useful information that will facilitate the development of aldose reductase inhibitors. PMID:27233987

  7. Occupational exposure to pesticides and respiratory health

    OpenAIRE

    Ali Mamane; Isabelle Baldi; Jean-François Tessier; Chantal Raherison; Ghislaine Bouvier

    2015-01-01

    This article aims to review the available literature regarding the link between occupational exposure to pesticides and respiratory symptoms or diseases. Identification of epidemiological studies was performed using PubMed. 41 articles were included, 36 regarding agricultural workers and five regarding industry workers. Among the 15 cross-sectional studies focusing on respiratory symptoms and agricultural pesticide exposure, 12 found significant associations with chronic cough, wheeze, dyspno...

  8. Clowns Benefit Children Hospitalized for Respiratory Pathologies

    OpenAIRE

    Giuseppe Curcio; Elena Isola; Giuseppe Paolone; Mario Bertini

    2011-01-01

    The study aims at evaluating health-generating function of humor therapy in a hospital ward hosting children suffering from respiratory pathologies. The main scope of this study is to investigate possible positive effects of the presence of a clown on both the clinical evolution of the on-going disease, and on some physiological and pain parameters. Forty-three children with respiratory pathologies participated in the study: 21 of them belonged to the experimental group (EG) and 22 children t...

  9. Respiratory Depression Caused by Heroin Use

    OpenAIRE

    Kadir Hakan Cansiz; Gokhan Inangil; Murat Kuyumcu; Ahmet Erturk Yedekci; Huseyin Sen; Sezai Ozkan; Guner Dagli

    2012-01-01

    Summary Heroin is a semisynthetic narcotic analgesic and heroin abuse is common due to its pleasure-inducing effect. For the last 30 years heroin abuse has become an important worldwide public health problem. Heroin can be administered in many different ways as preferred. Heroin affects many systems including respiratory system, cardiovascular system and particulary the central nervous system. Overdose use of heroin intravenously can be fatal due to respiratory depression. In this letter, we ...

  10. Respiratory health of cigar factory workers

    OpenAIRE

    Uitti, J; Nordman, H.; Huuskonen, M. S.; Roto, P.; Husman, K.; Reiman, M.

    1998-01-01

    OBJECTIVES: To determine whether occupational exposure to raw tobacco causes respiratory or allergic diseases, an excess of respiratory symptoms, a decrease in lung function, or parenchymal changes in chest radiography among Finnish cigar workers. METHODS: This cross sectional study included all Finnish cigar workers (n = 106) exposed to raw tobacco and also a group of unexposed matched referents. Data were collected with a self administered questionnaire, flow volume spirometry, measur...

  11. Respiratory System Model Take into Account Pathology

    OpenAIRE

    He Zhonghai; Ma Zhenhe

    2013-01-01

    In this study, nonlinear phenomenon of respiratory system is analyzed. Airway is partitioned into four parts by different morphology which causes different fluid dynamic character. Reasons that cause nonlinear phenomenon for different parts are given. To simplify the representation, corresponding parameters are selected to compromise the complicity and precision. Then, the suggested representation of respiratory system is summarized so that the model can be used easily in lung simulator.

  12. Effects of Pleural Effusion on Respiratory Function

    OpenAIRE

    Mitrouska, I; M Klimathianaki; NM Siafakas

    2004-01-01

    The accumulation of pleural effusion has important effects on respiratory system function. It changes the elastic equilibrium volumes of the lung and chest wall, resulting in a restrictive ventilatory effect, chest wall expansion and reduced efficiency of the inspiratory muscles. The magnitude of these alterations depends on the pleural fluid volume and the underlying disease of the respiratory system. The decrease in lung volume is associated with hypoxemia mainly due to an increase in right...

  13. Emergency thyroidectomy: Due to acute respiratory failure

    OpenAIRE

    Zulfu Bayhan; Sezgin Zeren; Bercis Imge Ucar; Isa Ozbay; Yalcin Sonmez; Metin Mestan; Onur Balaban; Nilufer Araz Bayhan; Mehmet Fatih Ekici

    2014-01-01

    INTRODUCTION: Giant cervical and mediastinal goiter may lead to acute respiratory failure caused by laryngotracheal compression and airway obstruction. Here, we present a case admitted to the emergency service with a giant goiter along with respiratory failure and poor general health status, which required urgent surgical intervention. PRESENTATION OF CASE: A 71-year-old female admitted to the emergency room with shortness of breath and poor general health status resulting from a giant cer...

  14. Airway Reflux, Cough and Respiratory Disease

    OpenAIRE

    Molyneux, Ian D.; Morice, Alyn H.

    2011-01-01

    It is increasingly accepted that the effects of gastro-oesophageal reflux are not limited to the gastrointestinal tract. The adjacent respiratory structures are also at risk from material ejected from the proximal oesophagus as a result of the failure of anatomical and physiological barriers. There is evidence of the influence of reflux on several respiratory and otorhinological conditions and although in many cases the precise mechanism has yet to be elucidated, the association alone opens p...

  15. Degeneracy as a Substrate for Respiratory Regulation

    OpenAIRE

    Mellen, Nicholas M.

    2010-01-01

    Recent studies in vivo and in vitro suggest that both respiratory rhythmogenesis and its central chemosensory modulation arise from multiple, mechanistically and/or anatomically distinct networks whose outputs are similar. These observations are consistent with degeneracy, defined as the ability of structurally distinct elements to generate similar function. This review argues that degeneracy is an essential feature of respiratory networks, ensuring the survival of the individual organism ove...

  16. Amyloid myopathy presenting with respiratory failure.

    OpenAIRE

    Ashe, J.; Borel, C O; Hart, G.; Humphrey, R L; Derrick, D A; Kuncl, R W

    1992-01-01

    Amyloidosis is a rare cause of myopathy. Its prominent or presenting feature may be respiratory failure. Physiological measurement of transdiaphragmatic pressure and biopsy specimens of muscle show the pathological mechanism to be diaphragm weakness due to amyloid infiltration of the diaphragm rather than parenchymal lung involvement. Thus amyloid myopathy even without the typical macroglossia and muscle pseudohypertrophy should be considered as one of the neurological causes of respiratory f...

  17. Treatment of respiratory failure in COPD

    Directory of Open Access Journals (Sweden)

    Stephan Budweiser

    2008-12-01

    Full Text Available Stephan Budweiser1, Rudolf A Jörres2, Michael Pfeifer1,31Center for Pneumology, Hospital Donaustauf, Donaustauf, Germany; 2Institute and Outpatient Clinic for Occupational, Social and Environmental Medicine, Ludwig-Maximilians-University, Munich, Germany; 3Department of Internal Medicine II, Division of Respirology, University of Regensburg, Regensburg, GermanyAbstract: Patients with advanced COPD and acute or chronic respiratory failure are at high risk for death. Beyond pharmacological treatment, supplemental oxygen and mechanical ventilation are major treatment options. This review describes the physiological concepts underlying respiratory failure and its therapy, as well as important treatment outcomes. The rationale for the controlled supply of oxygen in acute hypoxic respiratory failure is undisputed. There is also a clear survival benefit from long-term oxygen therapy in patients with chronic hypoxia, while in mild, nocturnal, or exercise-induced hypoxemia such long-term benefits appear questionable. Furthermore, much evidence supports the use of non-invasive positive pressure ventilation in acute hypercapnic respiratory failure. It application reduces intubation and mortality rates, and the duration of intensive care unit or hospital stays, particularly in the presence of mild to moderate respiratory acidosis. COPD with chronic hypercapnic respiratory failure became a major indication for domiciliary mechanical ventilation, based on pathophysiological reasoning and on data regarding symptoms and quality of life. Still, however, its relevance for long-term survival has to be substantiated in prospective controlled studies. Such studies might preferentially recruit patients with repeated hypercapnic decompensation or a high risk for death, while ensuring effective ventilation and the patients’ adherence to therapy.Keywords: respiratory failure, COPD, mechanical ventilation, non-invasive ventilation long-term oxygen therapy, chronic

  18. Preoperative respiratory physical therapy in cardiac surgery

    OpenAIRE

    Hulzebos, H.J.

    2006-01-01

    Cardiac surgery is one of the most common surgical procedures and accounts for more resources expended in cardiovascular medicine than any other single procedure. Because cardiac surgery involves sternal incision and cardiopulmonary bypass, patients usually have a restricted respiratory function in the postoperative period. Moreover, anesthesia and analgesia affect respiratory function during and after the surgical intervention, causing changes in lung volume, diaphragmatic dysfunction, respi...

  19. Respiratory Review of 2013: Critical Care Medicine

    OpenAIRE

    Choi, Hye Sook

    2013-01-01

    Several papers on respiratory and critical care published from March 2012 to February 2013 were reviewed. From these, this study selected and summarized ten articles, in which the findings were notable, new, and interesting: effects of high-frequency oscillation ventilation on acute respiratory distress syndrome (ARDS); safety and efficacy of hydroxyethyl starch as a resuscitation fluid; long-term psychological impairments after ARDS; safety and efficacy of dexmedetomidine for sedation; B-typ...

  20. Prevention of respiratory syncytial virus infection

    OpenAIRE

    Samson, L

    2009-01-01

    Respiratory syncytial virus (RSV) infection is the leading cause of lower respiratory tract infection in young children, with significant numbers of premature infants and those with other risk factors requiring hospitalization in Canada each year. Palivizumab, an RSV-specific monoclonal antibody, can reduce the hospitalization rate and severity of illness for a small group of high-risk or premature infants during their first RSV season. The present statement reviews the published literature a...