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Sample records for selenite chez rhodobacter

  1. Study of the selenite reduction in Rhodobacter sphaeroides f. sp. denitrificans

    International Nuclear Information System (INIS)

    Bernier-Pierru, B.

    2006-05-01

    Selenium is an essential element for all living organisms at the low level; however it becomes toxic and mutagenic at higher concentrations. The predominant forms of selenium in natural environments are selenate and selenite which are toxic. Bacteria can use several mechanisms of detoxification such as methylation in volatile compounds or reduction in elemental selenium. In this way, our model, Rhodobacter sphaeroides f. sp. denitrificans, is able to reduce selenite into selenium. We have combined biochemical and molecular approaches to better characterize the mechanism and protagonists of this reduction. After studying the physiological response of the bacterium in the presence of selenite, we screened a transposon library in order to isolate mutants with a weakened reduction ability. Two of these selected mutants are affected in genes involved in the molybdenum cofactor synthesis, moaA and mogA. Several reductases, the molybdo enzymes, required this cofactor. Furthermore the addition of tungsten, a competitor for the molybdenum, in the culture medium, dramatically reduces the rate of selenite reduction. These results strongly suggest that a molybdo enzyme is involved in one of the selenite reduction pathways. The potential role of different proteins has been investigated, especially for the nitrate reductase, the DMSO reductase and the biotin sulfoxide reductase. We have also selected a mutant affected in the smoM gene which encodes a peri-plasmic component of a TRAP transporter. The phenotype of this mutant suggests the involvement of this transporter in the selenite import. (author)

  2. Selenite -Se(4)- uptake mechanisms in the unicellular green alga Chlamydomonas reinhardtii: bioaccumulation and effects induced on growth and ultrastructure; Mecanismes de prise en charge du selenite - Se(4)-chez l'algue verte unicellulaire Chlamydomonas reinhardtii. Bioaccumulation et effets induits sur la croissance et l'ultrastructure

    Energy Technology Data Exchange (ETDEWEB)

    Morlon, H

    2005-03-15

    Selenium is an essential element, but becomes very toxic at higher concentrations. It occurs in the environment at concentrations ranging from nM to {mu}M and selenium pollution is a worldwide phenomenon. This works aims at improving the knowledge on the interactions between selenite - Se(IV) - and a freshwater phyto-planktonic organism: the unicellular green algae Chlamydomonas reinhardtii. The aim of the performed experiments were: i) to investigate selenite -Se(IV)- uptake mechanisms in C. reinhardtii, using Se{sup 75} as a tracer in short term exposures (<1 h); ii) to assess selenite toxicity as measured with growth impairment and ultrastructural damage (with EDAX-TEM analysis), using long term exposures (96 h) to stable selenite; iii) to evaluate the bioaccumulation capacity of selenite and its potential links with toxicity. Short-term experiments revealed a negligible adsorption and a time-dependent linear absorption with an estimated absorbed flux of about 0.2 nmol.m{sup -2}.nM{sup -1}.h{sup -1}. The uptake was proportional to ambient levels in a broad range of intermediate concentrations (from nM to {mu}M). However, fluxes were higher at very low concentrations (< nM), and decrease with increasing high concentrations ( > {mu}M), suggesting that a high affinity but rapidly saturated transport mechanism could be used at low concentrations, in parallel with a low affinity mechanism that would only saturate at high concentrations ({approx}mM). The latter could involve transporters used by sulphate and nitrates, as suggested by the inhibition of selenite uptake by those element. Se(IV) speciation changes with pH did not induce significant effect on bioavailability. On the basis of the relationship between Se concentration and maximal cell density achieved, an EC50 of 80 {mu}M ([64; 98]) was derived. No adaptation mechanism were observed as the same the same toxicity was quantified for Se-pre-exposed algae. Observations by TEM suggested chloroplasts as the first

  3. Physiological Investigation Of Rhodobacter Sphaeroides

    OpenAIRE

    Özmeral, Özge

    2013-01-01

    Rhodobacter sphaeroides metabolik olarak geniş bir organizasyona sahip olan α-3 mor non-sülfür bir organizmadır. Oksijensiz ortamda R. sphaeroides hücreleri fotosentez, solunum ve fermantasyon yaparak çoğalabilir. R. sphaeroides hücrelerinde bulunan fotosentez yapımından sorumlu olan fotosentetik yapıları oksijenin varlığında oksijen tarafından zarara uğratıldığından fotosentez sadece oksijensiz ortamda meydana gelebilir. R. sphaeroides hücreleri fotosentezi fotoheterotrofik ve fotoototr...

  4. Ontogenic changes in selenite metabolism in rats

    International Nuclear Information System (INIS)

    Ostadalova, I.; Babicky, A.; Kopoldova, J.

    1982-01-01

    Radioselenium concentration and excretion was studied after administration of 75 Se-labelled selenite to male rats during ontogeny. The concentration of radioselenium in individual organs decreases with increasing age. The largest differences between young and adults were in the quantity and quality of excreted substances. During 2 h after the administration of 20 μmol selenite/kg young rats excreted 2.4% of the dose, essentially in the urine only, whilst adults excreted a total of 11%, distributed equally in breath and urine. The part excreted as methylated metabolites was 0.1% of the administered dose in young and 6.3% in adult rats. These results support the hypothesis that the differences in the sensitivity to the toxic action of selenite between young and adult rats can be due to ontogenic differences in selenium metabolism. (orig.)

  5. Jeux chez les Touaregs

    OpenAIRE

    Bernus, E.

    2012-01-01

    Parmi les jeux pratiqués par les Touaregs, il faut distinguer les jeux sportifs qui opposent deux équipes ou deux hommes, des jeux de société dans un cadre inscrit dans le sable, et les jeux d’esprit, véritables joutes verbales ; enfin, il faut signaler la construction par les enfants de jouets. Un certain nombre de jeux sont connus chez d’autres populations africaines. L’ouvrage de Charles Béart, Jeux et jouets de l’Ouest africain (1955), nous permet d’utiles comparaisons. Il est donc intére...

  6. Reduction of chalcogen oxyanions and generation of nanoprecipitates by the photosynthetic bacterium Rhodobacter capsulatus

    Energy Technology Data Exchange (ETDEWEB)

    Borghese, Roberto, E-mail: roberto.borghese@unibo.it [Department of Pharmacy and Biotechnology, University of Bologna (Italy); Baccolini, Chiara; Francia, Francesco [Department of Pharmacy and Biotechnology, University of Bologna (Italy); Sabatino, Piera [Department of Chemistry G. Ciamician, University of Bologna (Italy); Turner, Raymond J. [Department of Biological Sciences, University of Calgary, Calgary, Alberta (Canada); Zannoni, Davide, E-mail: davide.zannoni@unibo.it [Department of Pharmacy and Biotechnology, University of Bologna (Italy)

    2014-03-01

    Graphical abstract: - Highlights: • R. capsulatus cells produce extracellular chalcogens nanoprecipitates when lawsone is present. • Lawsone acts as a redox mediator from reducing equivalents to tellurite and selenite. • Nanoprecipitates production depends on carbon source and requires metabolically active cells. • Te{sup 0} and Se{sup 0} nanoprecipitates are identified by X-ray diffraction (XRD) spectroscopy. - Abstract: The facultative photosynthetic bacterium Rhodobacter capsulatus is characterized in its interaction with the toxic oxyanions tellurite (Te{sup IV}) and selenite (Se{sup IV}) by a highly variable level of resistance that is dependent on the growth mode making this bacterium an ideal organism for the study of the microbial interaction with chalcogens. As we have reported in the past, while the oxyanion tellurite is taken up by R. capsulatus cells via acetate permease and it is reduced to Te{sup 0} in the cytoplasm in the form of splinter-like black intracellular deposits no clear mechanism was described for Se{sup 0} precipitation. Here, we present the first report on the biotransformation of tellurium and selenium oxyanions into extracellular Te{sup 0} and Se{sup 0}nanoprecipitates (NPs) by anaerobic photosynthetically growing cultures of R. capsulatus as a function of exogenously added redox-mediator lawsone, i.e. 2-hydroxy-1,4-naphthoquinone. The NPs formation was dependent on the carbon source used for the bacterial growth and the rate of chalcogen reduction was constant at different lawsone concentrations, in line with a catalytic role for the redox mediator. X-ray diffraction (XRD) analysis demonstrated the Te{sup 0} and Se{sup 0} nature of the nanoparticles.

  7. Radioactive sodium selenite in the differentiation of hepatic lesions

    Energy Technology Data Exchange (ETDEWEB)

    Houlder, A E [King Edward VIII Hospital, Durban (South Africa). Dept. of Radiophysics

    1977-06-11

    Selenium-75 selenite and technetium-99m sulphur colloid scans were performed on 38 South African Blacks with intrahepatic space-occupying lesions. Uptake of selenite was demonstrated in the 'cold area' on the sulphur colloid scan in 17 out of 19 patients with hepatocellular carcinoma, but in 16 patients with amoebic liver abscess there was no uptake of selenite in the 'cold area'. In 3 patients with secondary involvement in the liver, 2 had positive uptake of selenite in the affected region. /sup 75/Se selenite was found to be useful in the differential diagnosis of intrahepatic lesions.

  8. Short range order of selenite glasses

    Czech Academy of Sciences Publication Activity Database

    Neov, S.; Gerasimova, I.; Yordanov, S.; Lakov, L.; Mikula, Pavol; Lukáš, Petr

    1999-01-01

    Roč. 40, č. 2 (1999), s. 111-112 ISSN 0031-9090 R&D Projects: GA AV ČR KSK1010104 Keywords : short range * selenite glasses Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.822, year: 1999

  9. Sodium selenite as a new rodenticide

    Directory of Open Access Journals (Sweden)

    Goran Jokić

    2014-09-01

    Full Text Available Rodents are the most destructive group of small mammalian pests considering the overall damage that they cause by feeding and other activities, or as vectors of many disease agents. In practice, chemical rodenticides have been the most widespread and most effective method of control of commensal (Mus musculus, Rattus norvegicus and R. rattus and most harmful field rodent pests (Apodemus sylvaticus, A. agrarius and Microtus arvalis. After anticoagulant and vitamin D3 rodenticides, which were introduced worldwide in the 1980s, no other chemical compound has had a comparable role as a rodenticide in practice. In the past decade, commercial baits containing 0.1% sodium selenite have also been registered in Serbia in various formulations both for controlling rodents indoors and in the field. Data on sodium selenite as a rodenticide have been scarce. The present paper surveys research data reported so far, analyzing and drawing conclusions regarding the validity and feasibility of sodium selenite as a method of rodent control with reference to the available ecotoxicological data.

  10. Differential diagnosis of scintigraphic brain centres by 75Se selenite

    International Nuclear Information System (INIS)

    Bestagno, M.; Garraffa, V.; Rembado, R.; Guerra, U.

    1975-01-01

    Since standard brain scintigraphy with sup(99m)Tc is not always adequate for a satisfactory differential diagnosis of the radioactive foci detected, the possibilities of 75 Se sodium selenite were investigated. It was observed that in centres due to a vascular lesion the selenite concentration is always low, rising steeply in neoplasmic foci. The 75 Se-selenite scintigraphic method is considered highly valid, complementing that of sup(99m)Tc when this latter is unsuitable for diagnosis of the nature of cerebral foci [fr

  11. Ammonium and methylammonium transport in Rhodobacter sphaeroides

    International Nuclear Information System (INIS)

    Cordts, M.L.; Gibson, J.

    1987-01-01

    Rhodobacter spheroides maintained intracellular ammonium pools of 1.1 to 2.6 mM during growth in several fixed nitrogen sources as well as during diazotrophic growth. Addition of 0.15 mM NH 4 + to washed, nitrogen-free cell suspensions was followed by linear uptake of NH 4 + from the medium and transient formation of intracellular pools of 0.9 to 1.5 mM NH 4 + . Transport of NH 4 + was shown to be independent of assimilation by glutamine synthetase because intracellular pools of over 1 mM represented NH 4 + concentration gradients of at least 100-fold across the cytoplasmic membrane. Ammonium pools of over 1 mM were also found in non-growing cell suspensions in nitrogen-free medium after glutamine synthetase was inhibited with methionine sulfoximine. In NH 4 + -free cell suspensions, methylammonium ( 14 CH 3 NH 3 + ) was taken up rapidly, and intracellular concentrations of 0.4 to 0.5 mM were maintained. The 14 CN 3 NH 3 + pool was not affected by methionine sulfoximine. Unlike NH 4 + uptake, 14 CH 3 NH 3 + uptake in nitrogen-free cell suspensions was repressed by growth in NH 4 + . These results suggest that R. sphaeroides may produce an NH 4 + -specific transport system in addition to the NH 4 + / 14 CH 3 NH 3 + transporter. This second transporter is able to produce normal-size NH 4 + pools but has very little affinity for 14 CH 3 NH 3 + and is not repressed by growth in high concentrations of NH 4 +

  12. Ammonium and methylammonium transport in Rhodobacter sphaeroides

    Energy Technology Data Exchange (ETDEWEB)

    Cordts, M.L.; Gibson, J.

    1987-04-01

    Rhodobacter spheroides maintained intracellular ammonium pools of 1.1 to 2.6 mM during growth in several fixed nitrogen sources as well as during diazotrophic growth. Addition of 0.15 mM NH/sub 4//sup +/ to washed, nitrogen-free cell suspensions was followed by linear uptake of NH/sub 4//sup +/ from the medium and transient formation of intracellular pools of 0.9 to 1.5 mM NH/sub 4//sup +/. Transport of NH/sub 4//sup +/ was shown to be independent of assimilation by glutamine synthetase because intracellular pools of over 1 mM represented NH/sub 4//sup +/ concentration gradients of at least 100-fold across the cytoplasmic membrane. Ammonium pools of over 1 mM were also found in non-growing cell suspensions in nitrogen-free medium after glutamine synthetase was inhibited with methionine sulfoximine. In NH/sub 4//sup +/-free cell suspensions, methylammonium (/sup 14/CH/sub 3/NH/sub 3//sup +/) was taken up rapidly, and intracellular concentrations of 0.4 to 0.5 mM were maintained. The /sup 14/CN/sub 3/NH/sub 3//sup +/ pool was not affected by methionine sulfoximine. Unlike NH/sub 4//sup +/ uptake, /sup 14/CH/sub 3/NH/sub 3//sup +/ uptake in nitrogen-free cell suspensions was repressed by growth in NH/sub 4//sup +/. These results suggest that R. sphaeroides may produce an NH/sub 4//sup +/-specific transport system in addition to the NH/sub 4//sup +///sup 14/CH/sub 3/NH/sub 3//sup +/ transporter. This second transporter is able to produce normal-size NH/sub 4//sup +/ pools but has very little affinity for /sup 14/CH/sub 3/NH/sub 3//sup +/ and is not repressed by growth in high concentrations of NH/sub 4//sup +/.

  13. Depistage clinique des infections sexuellement transmissibles chez ...

    African Journals Online (AJOL)

    Depistage clinique des infections sexuellement transmissibles chez les personnes vivant avec le VIH suivies au Centre de Traitement Ambulatoire du Centre National Hospitalier Universitaire Hubert Koutoukou Maga de Cotonou.

  14. Les manifestations cardiovasculaires chez les hemodialyses ...

    African Journals Online (AJOL)

    Le but de l'étude est d'analyser sur une période de 12 mois chez 75 patients en hémodialyse chronique, âgés de 38ans en moyenne, le les aspects cliniques, thérapeutiques et évolutifs des manifestations cardiovasculaires. La prévalence est de 87,20% chez les patients. Les signes fonctionnels les plus fréquents sont la ...

  15. Selenite cataract and its attenuation by vitamin E in wistar rats.

    Directory of Open Access Journals (Sweden)

    Mathew Joe

    2003-01-01

    Full Text Available Purpose: To study the role of vitamin E in preventing cataract formation in experimental animals. Methods: An experimental model (selenite cataract was selected for this study. Selenite cataract was produced in rats by subcutaneous administration of sodium selenite. Biochemical and histological changes following induction of selenite cataract in weanling wistar rats were studied vis-à-vis the role of vitamin E in attenuating or preventing cataractogenesis. Results: Vitamin E was capable of preventing selenite cataractogenesis. Selenite cataract did not develop in 91.6% (11 of 12 and 76.7% (8 of 12 vitamin E treated rats, when administered on the 12th and 10th post partum day respectively. Conclusion: The study confirmed that selenite induced cataract in wistar rats is attenuated by vitamin E.

  16. The mechanism of interaction between cisplatin and selenite

    NARCIS (Netherlands)

    Baldew, G S; Mol, J G; de Kanter, F J; van Baar, B; De Goeij, J J; Vermeulen, N P

    1991-01-01

    Cisplatin is a widely used antitumor drug, highly effective in the treatment of several tumors. Cisplatin exerts its antitumor activity through an interaction with DNA, which results in the formation of bidentate adducts. An important side-effects of cisplatin is nephrotoxicity. Selenite can reduce

  17. Experimental and iatrogenic poisoning by sodium selenite in pigs

    Directory of Open Access Journals (Sweden)

    Paulo V. Peixoto

    Full Text Available ABSTRACT: Following a case of iatrogenic selenium poisoning in a young pig, an experimental study was carry out. Sodium selenite was orally and parenterally administered to 13 pigs that were subdivided into three groups (G1, G2 and G3. The animals in groups G1 and G3 received sodium selenite intramuscularly (IM, G1 received a comercial formula, and G3 received sodium selenite mixed with distilled water at different dosages, and those in group G2 were fed commercial sodium selenite. Acute and subacute poisoning was observed in both groups, although the onset of clinical signs was slower in group G2. Only one pig (in group G1 that had received the highest dose showed a peracute course. Apathy, anorexia, dyspnea, vomiting, muscular tremors, proprioceptive deficit, ataxia and paresis of the hind limbs progressing to the front limbs evolving to tetraplegia were observed. Postmortem findings differed whether the animals received the injected (G1 and G3 or oral (G2 sodium selenite. The liver was moderately atrophic in some animals of G2. Some of the animals in groups G1 and G3 presented with lung edema. One pig in G3 had yellowish-brown areas in the ventral horns of the cervical intumescences of the spinal cord. The most important histological changes were present in the ventral horns of the cervical and lumbar intumescences of the spinal cord. In one animal, changes were present in the brainstem and mesencephalon. The initial lesion was a perivascular and astrocyte edema that progressing to lysis and death of astrocytes and neurons. In the chronic stage of the lesions, there were extensive areas of liquefaction necrosis with perivascular lymphocytic and histiocytic infiltration and occasional eosinophils. It seems that disruption of the blood-brain barrier due to astrocyte edema is the most likely mechanism of CNS lesion.

  18. Bioremediation of lead contaminated soil with Rhodobacter sphaeroides.

    Science.gov (United States)

    Li, Xiaomin; Peng, Weihua; Jia, Yingying; Lu, Lin; Fan, Wenhong

    2016-08-01

    Bioremediation with microorganisms is a promising technique for heavy metal contaminated soil. Rhodobacter sphaeroides was previously isolated from oil field injection water and used for bioremediation of lead (Pb) contaminated soil in the present study. Based on the investigation of the optimum culturing conditions and the tolerance to Pb, we employed the microorganism for the remediation of Pb contaminated soil simulated at different contamination levels. It was found that the optimum temperature, pH, and inoculum size for R. sphaeroides is 30-35 °C, 7, and 2 × 10(8) mL(-1), respectively. Rhodobacter sphaeroides did not remove the Pb from soil but did change its speciation. During the bioremediation process, more available fractions were transformed to less accessible and inert fractions; in particular, the exchangeable phase was dramatically decreased while the residual phase was substantially increased. A wheat seedling growing experiment showed that Pb phytoavailability was reduced in amended soils. Results inferred that the main mechanism by which R. sphaeroides treats Pb contaminated soil is the precipitation formation of inert compounds, including lead sulfate and lead sulfide. Although the Pb bioremediation efficiency on wheat was not very high (14.78% root and 24.01% in leaf), R. sphaeroides remains a promising alternative for Pb remediation in contaminated soil. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Characterization of the selenite uptake mechanism in the coccolithophore Emiliania huxleyi (Haptophyta).

    Science.gov (United States)

    Araie, Hiroya; Sakamoto, Kou; Suzuki, Iwane; Shiraiwa, Yoshihiro

    2011-07-01

    The marine coccolithophore Emiliania huxleyi (Haptophyta) requires selenium as an essential element for growth, and the active species absorbed is selenite, not selenate. This study characterized the selenite uptake mechanism using ⁷⁵Se as a tracer. Kinetic analysis of selenite uptake showed the involvement of both active and passive transport processes. The active transport was suppressed by 0.5 mM vanadate, a membrane-permeable inhibitor of H⁺-ATPase, at pH 8.3. When the pH was lowered from 8.3 to 5.3, the selenite uptake activity greatly increased, even in the presence of vanadate, suggesting that the H⁺ concentration gradient may be a motive force for selenite transport. [⁷⁵Se]Selenite uptake at selenite-limiting concentrations was hardly affected by selenate, sulfate and sulfite, even at 100 μM. In contrast, 3 μM orthophosphate increased the K(m) 5-fold. These data showed that HSeO₃⁻, a dominant selenite species at acidic pH, is the active species for transport through the plasma membrane and transport is driven by ΔpH energized by H⁺-ATPase. Kinetic analysis showed that the selenite uptake activity was competitively inhibited by orthophosphate. Furthermore, the active selenite transport mechanism was shown to be induced de novo under Se-deficient conditions and induction was suppressed by the addition of either sufficient selenite or cycloheximide, an inhibitor of de novo protein synthesis. These results indicate that E. huxleyi cells developed an active selenite uptake mechanism to overcome the disadvantages of Se limitation in ecosystems, maintaining selenium metabolism and selenoproteins for high viability.

  20. Selenite protects Caenorhabditis elegans from oxidative stress via DAF-16 and TRXR-1.

    Science.gov (United States)

    Li, Wen-Hsuan; Shi, Yeu-Ching; Chang, Chun-Han; Huang, Chi-Wei; Hsiu-Chuan Liao, Vivian

    2014-04-01

    Selenium is an essential micronutrient. In the present study, trace amount of selenite (0.01 μM) was evaluated for oxidative stress resistance and potential associated factors in Caenorhabditis elegans. Selenite-treated C. elegans showed an increased survival under oxidative stress and thermal stress compared to untreated controls. Further studies demonstrated that the significant stress resistance of selenite on C. elegans could be attributed to its in vivo free radical-scavenging ability. We also found that the oxidative and thermal stress resistance phenotypes by selenite were absent from the forkhead transcription factor daf-16 mutant worms. Moreover, selenite influenced the subcellular distribution of DAF-16 in C. elegans. Furthermore, selenite increased mRNA levels of stress-resistance-related proteins, including superoxide dismutase-3 and heat shock protein-16.2. Additionally, selenite (0.01 μM) upregulated expressions of transgenic C. elegans carrying sod-3::green fluorescent protein (GFP) and hsp-16.2::GFP, whereas this effect was abolished by feeding daf-16 RNA interference in C. elegans. Finally, unlike the wild-type N2 worms, the oxidative stress resistance phenotypes by selenite were both absent from the C. elegans selenoprotein trxr-1 mutant worms and trxr-1 mutants feeding with daf-16 RNA interference. These findings suggest that the antioxidant effects of selenite in C. elegans are mediated via DAF-16 and TRXR-1. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. La spermiation chez le brochet.

    Directory of Open Access Journals (Sweden)

    DE MONTALEMBERT G.

    1980-01-01

    Full Text Available L'évolution quantitative et qualitative de la production de sperme au cours de la période de spermiation a été étudiée chez des brochets maintenus en captivité dans un étang de 400 m2. Le sperme est prélevé toutes les semaines à partir du début de février, et pendant près de 2 mois. La quantité de sperme recueillie est très faible et présente de fortes variations individuelles ; elle augmente progressivement jusqu'à la 5me semaine et décroit ensuite. La quantité moyenne de sperme récoltée par mâle est de l'ordre de 0,7 ml/semaine et varie considérablement d'un mâle à l'autre (0.07 à 1,5 ml. La concentration du sperme en spermatozoïdes varie entre 18 et 25 milliards par ml ( X = 21,5 109 + 2,11. La quantité de spermatozoïdes récoltée par semaine est de 28,5 106 + 26,4/kg de poids corporel. La qualité du sperme appréciée par l'intensité et la durée de motilité suit une évolution similaire à celle de la quantité de sperme récoltée avec des valeurs maximales à 4 semaines et minimales en début et fin de période de prélèvement. Les premières ovulations détectées sur des femelles stockées dans les mêmes conditions que les mâles ont été observées à la 6me semaine de prélèvements alors que les performances de spermiation avaient déjà fortement déclinées. Il est vraisemblable que les conditions expérimentales particulièrement traumatisantes pour les mâles ont affecté prématurément la spermiation, amplifiant ainsi le décalage fréquemment observé entre les périodes de spermiation et d'ovulation.

  2. Surface complexation of selenite on goethite: MO/DFT geometry and charge distribution

    NARCIS (Netherlands)

    Hiemstra, T.; Rietra, R.P.J.J.; Riemsdijk, van W.H.

    2007-01-01

    The adsorption of selenite on goethite (alpha-FeOOH) has been analyzed with the charge distribution (CD) and the multi-site surface complexation (MUSIC) model being combined with an extended Stem (ES) layer model option. The geometry of a set of different types of hydrated iron-selenite complexes

  3. Trieb et énergie chez Herder

    OpenAIRE

    Pénisson, Pierre

    2011-01-01

    Herder s’inspire à la fois de la philosophie leibnizienne de la force, de la théorie d’Albrecht von Haller sur l’excitabilité (Reizbarkeit) et des pensées françaises de l’énergie, que l’on trouve aussi chez Sulzer à Berlin et James Harris en Angleterre, et d’une autre façon chez Hamann que commentera Hegel. Mais le Trieb est plus qu’une concentration de force, et la critique herdérienne des pensées françaises de l’énergie ou du culte allemand du génie retrouve les arguments du premier discour...

  4. The Comparative Studies of Binding Activity of Curcumin and Didemethylated Curcumin with Selenite: Hydrogen Bonding vs Acid-Base Interactions

    Science.gov (United States)

    Liao, Jiahn-Haur; Wu, Tzu-Hua; Chen, Ming-Yi; Chen, Wei-Ting; Lu, Shou-Yun; Wang, Yi-Hsuan; Wang, Shao-Pin; Hsu, Yen-Min; Huang, Yi-Shiang; Huang, Zih-You; Lin, Yu-Ching; Chang, Ching-Ming; Huang, Fu-Yung; Wu, Shih-Hsiung

    2015-12-01

    In this report, the in vitro relative capabilities of curcumin (CCM) and didemethylated curcumin (DCCM) in preventing the selenite-induced crystallin aggregation were investigated by turbidity tests and isothermal titration calorimetry (ITC). DCCM showed better activity than CCM. The conformers of CCM/SeO32- and DCCM/SeO32- complexes were optimized by molecular orbital calculations. Results reveal that the selenite anion surrounded by CCM through the H-bonding between CCM and selenite, which is also observed via IR and NMR studied. For DCCM, the primary driving force is the formation of an acid-base adduct with selenite showing that the phenolic OH group of DCCM was responsible for forming major conformer of DCCM. The formation mechanisms of selenite complexes with CCM or DCCM explain why DCCM has greater activity than CCM in extenuating the toxicity of selenite as to prevent selenite-induced lens protein aggregation.

  5. Transcriptional Response of Selenopolypeptide Genes and Selenocysteine Biosynthesis Machinery Genes in Escherichia coli during Selenite Reduction.

    Science.gov (United States)

    Tetteh, Antonia Y; Sun, Katherine H; Hung, Chiu-Yueh; Kittur, Farooqahmed S; Ibeanu, Gordon C; Williams, Daniel; Xie, Jiahua

    2014-01-01

    Bacteria can reduce toxic selenite into less toxic, elemental selenium (Se(0)), but the mechanism on how bacterial cells reduce selenite at molecular level is still not clear. We used Escherichia coli strain K12, a common bacterial strain, as a model to study its growth response to sodium selenite (Na2SeO3) treatment and then used quantitative real-time PCR (qRT-PCR) to quantify transcript levels of three E. coli selenopolypeptide genes and a set of machinery genes for selenocysteine (SeCys) biosynthesis and incorporation into polypeptides, whose involvements in the selenite reduction are largely unknown. We determined that 5 mM Na2SeO3 treatment inhibited growth by ∼ 50% while 0.001 to 0.01 mM treatments stimulated cell growth by ∼ 30%. Under 50% inhibitory or 30% stimulatory Na2SeO3 concentration, selenopolypeptide genes (fdnG, fdoG, and fdhF) whose products require SeCys but not SeCys biosynthesis machinery genes were found to be induced ≥2-fold. In addition, one sulfur (S) metabolic gene iscS and two previously reported selenite-responsive genes sodA and gutS were also induced ≥2-fold under 50% inhibitory concentration. Our findings provide insight about the detoxification of selenite in E. coli via induction of these genes involved in the selenite reduction process.

  6. Transcriptional Response of Selenopolypeptide Genes and Selenocysteine Biosynthesis Machinery Genes in Escherichia coli during Selenite Reduction

    Directory of Open Access Journals (Sweden)

    Antonia Y. Tetteh

    2014-01-01

    Full Text Available Bacteria can reduce toxic selenite into less toxic, elemental selenium (Se0, but the mechanism on how bacterial cells reduce selenite at molecular level is still not clear. We used Escherichia coli strain K12, a common bacterial strain, as a model to study its growth response to sodium selenite (Na2SeO3 treatment and then used quantitative real-time PCR (qRT-PCR to quantify transcript levels of three E. coli selenopolypeptide genes and a set of machinery genes for selenocysteine (SeCys biosynthesis and incorporation into polypeptides, whose involvements in the selenite reduction are largely unknown. We determined that 5 mM Na2SeO3 treatment inhibited growth by ∼50% while 0.001 to 0.01 mM treatments stimulated cell growth by ∼30%. Under 50% inhibitory or 30% stimulatory Na2SeO3 concentration, selenopolypeptide genes (fdnG, fdoG, and fdhF whose products require SeCys but not SeCys biosynthesis machinery genes were found to be induced ≥2-fold. In addition, one sulfur (S metabolic gene iscS and two previously reported selenite-responsive genes sodA and gutS were also induced ≥2-fold under 50% inhibitory concentration. Our findings provide insight about the detoxification of selenite in E. coli via induction of these genes involved in the selenite reduction process.

  7. Protective effects of ebselen on sodium-selenite-induced experimental cataract in rats.

    Science.gov (United States)

    Aydemir, Orhan; Güler, Mete; Kaya, Mehmet Kaan; Deniz, Nurettin; Üstündağ, Bilal

    2012-12-01

    To determine whether ebselen has a protective effect or antioxidative potential in a sodium-selenite-induced experimental cataract model. Fırat University, Elazığ, Turkey. Experimental study. Twenty-one Sprague-Dawley rat pups were randomly divided into a control group, a sodium-selenite-induced-cataract group, and an ebselen-treated group; each group contained 7 rat pups. Rats in the control group received dimethyl sulfoxide (DMSO) intraperitoneally only and rats in the sodium-selenite-induced-cataract group received 30 nmol/g body weight sodium selenite subcutaneously and DMSO intraperitoneally 10 days postpartum. Rats in the ebselen group received 30 nmol/g body weight sodium selenite subcutaneously 10 days postpartum and were treated with 5 mg/kg body weight ebselen once a day for 4 consecutive days. Cataract development was assessed weekly for 3 weeks by slitlamp examination and graded using a scale. Reduced glutathione (GSH), total nitrite, and malondialdehyde (MDA) levels in lens supernatants were measured at the end of 3 weeks. In the control group, all lenses were clear. In the ebselen-treated group, the mean cataract stage was significantly lower than in the sodium-selenite-induced-cataract group (P = .022). The GSH levels were significantly lower in the sodium-selenite-induced-cataract group than in the control and ebselen groups (P ebselen group than in the sodium-selenite-induced-cataract group (P ebselen group (P = .001). Ebselen had a protective effect on cataract development in a sodium-selenite-induced experimental model. The protective effect of ebselen appears to be due to inhibition of oxidative stress. No author has a financial or proprietary interest in any material or method mentioned. Copyright © 2012 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  8. ADP-ribosylation of dinitrogenase reductase in Rhodobacter capsulatus

    International Nuclear Information System (INIS)

    Jouanneau, Y.; Roby, C.; Meyer, C.M.; Vignais, P.M.

    1989-01-01

    In the photosynthetic bacterium Rhodobacter capsulatus, nitrogenase is regulated by a reversible covalent modification of Fe protein or dinitrogenase reductase (Rc2). The linkage of the modifying group to inactive Rc2 was found to be sensitive to alkali and to neutral hydroxylamine. Complete release of the modifying group was achieved by incubation of inactive Rc2 in 0.4 or 1 M hydroxylamine. After hydroxylamine treatment of the Rc2 preparation, the modifying group could be isolated and purified by affinity chromatography and ion-exchange HPLC. The modifying group comigrated with ADP-ribose on both ion-exchange HPLC and thin-layer chromatography. Analyses by 31 P NMR spectroscopy and mass spectrometry provided further evidence that the modifying group was ADP-ribose. The NMR spectrum of inactive Rc2 exhibited signals characteristic of ADP-ribose; integration of these signals allowed calculation of a molar ration ADP-ribose/Rc2 of 0.63. A hexapeptide carrying the ADP-ribose moiety was purified from a subtilisin digest of inactive Rc2. The structure of this peptide, determined by amino acid analysis and sequencing, is Gly-Arg(ADP-ribose)-Gly-Val-Ile-Thr. This structure allows identification of the binding site for ADP-ribose as Arg 101 of the polypeptide chain of Rc2. It is concluded that nitrogenase activity in R. capsulatus is regulated by reversible ADP-ribosylation of a specific arginyl residue of dinitrogenase reductase

  9. Biological 60Co radiation effects on mouse embryos in the presence of sodium selenite

    International Nuclear Information System (INIS)

    Bellini, M.H.; Mastro, N.L. del.

    1988-09-01

    A single dose of sodium selenite (0,5 mg Se/Kg b.w.) was injected intraperitoneally into mice on day 17 pregnancy, 2h before 1.5 and 3.0 Gy whole body gamma irradiation. Irradiation produced a growth impairment in the newborns. Weight improvement as a function of age offspring from irradiated mice decreased proportionally to applied dose. Administration of selenite results also in a decrease of growth rate. Nevertheless, when irradiation and selenite treatments were combined, no additive effect can be observed, suggesting that selenium pretreatment would exert some protection against radiation-induced retardation of growth. (author) [pt

  10. Photovaporisation prostatique au laser chez les patients à haut ...

    African Journals Online (AJOL)

    infection urinaire chez 5 patients (10.6%), une dysurie chez 4 patients et une hémorragie retardée chez 4 autres (8.5%). Un seul de ces patients a nécessité une transfusion sanguine et aucun patient n'a nécessité une réintervention. En 3 mois de suivi un seul patient a nécessité une incision du col vésical pour sclérose du ...

  11. Arsenic uptake and accumulation in rice (Oryza sativa L.) with selenite fertilization and water management.

    Science.gov (United States)

    Wan, Yanan; Camara, Aboubacar Younoussa; Huang, Qingqing; Yu, Yao; Wang, Qi; Li, Huafen

    2018-07-30

    The accumulation of arsenic (As) in rice grain is a potential threat to human health. Our study investigated the possible mediatory role of selenite fertilization on As uptake and accumulation by rice (Oryza sativa L.) under different water management regimes (aerobic or flooded) in a pot experiment. Soil solutions were also extracted during the growing season to monitor As dynamics. Results showed that As contents in the soil solutions, seedlings, and mature rice were higher under flooded than under aerobic water management. Under aerobic conditions, selenite additions slightly increased As concentrations in soil solutions (in the last two samplings), but decreased As levels in rice plants. Relative to the control, 0.5 mg kg -1 selenite decreased rice grain As by 27.5%. Under flooded conditions, however, selenite additions decreased As in soil solutions, while increased As in rice grain. Tendencies also showed that selenite additions decreased the proportion of As in rice shoots both at the seedling stage and maturity, and were more effective in aerobic soil. Our results demonstrate that the effect of selenite fertilizer on As accumulation by rice is related to water management. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. Ecriture traumatique de la problematique de la jeunesse chez deux ...

    African Journals Online (AJOL)

    Ecriture traumatique de la problematique de la jeunesse chez deux romanciers africains froncophones: Ahmadou kourouma et boubacar boris diop, ou l'Afrique au pied du mur de la crise de la conscience Africaine.

  13. Hydrogen production by co-cultures of Lactobacillus and a photosynthetic bacterium, Rhodobacter sphaeroides RV

    Energy Technology Data Exchange (ETDEWEB)

    Asada, Yasuo; Ishimi, Katsuhiro [Department of General Education, College of Science and Technology, Nihon University, Narashinodai, Chiba 274-8501 (Japan); Tokumoto, Masaru; Aihara, Yasuyuki; Oku, Masayo; Kohno, Hideki [Department of Applied Molecular Chemistry, College of Industrial Technology, Nihon University, Izumi-cho, Chiba 275-8575 (Japan); Wakayama, Tatsuki; Miyake, Jun [Research Institute for Cell Engineering, National Institute of Advanced Industrial Science and Technology, Nakoji, Amagasaki, Hyogo 661-0974 (Japan); Tomiyama, Masamitsu [Genetic Diversity Department, National Institute of Agrobiological Science, Tsukuba, Ibaraki 305-8602 (Japan)

    2006-09-15

    Hydrogen production with glucose by using co-immobilized cultures of a lactic acid bacterium, Lactobacillus delbrueckii NBRC13953, and a photosynthetic bacterium, Rhodobacter sphaeroides RV, in agar gels was studied. Glucose was converted to hydrogen gas in a yield of 7.1mol of hydrogen per mole of glucose at a maximum under illuminated conditions. (author)

  14. Electrochemical determination of hydrogen peroxide using Rhodobacter capsulatus cytochrome c peroxidase at a gold electrode

    NARCIS (Netherlands)

    De Wael, K.; Buschop, H.; Heering, H.A.; De Smet, L.; Van Beeumen, J.; Devreese, B.; Adriaens, A.

    2007-01-01

    We describe the redox behaviour of horse heart cytochrome c (HHC) and Rhodobacter capsulatus cytochrome c peroxidase (RcCCP) at a gold electrode modified with 4,4?-bipyridyl. RcCCP shows no additional oxidation or reduction peaks compared to the electrochemistry of only HHC, which indicates that it

  15. ISOLATION AND CHARACTERIZATION OF THE HIGH-AFFINITY K+-TRANSLOCATING ATPASE FROM RHODOBACTER-SPHAEROIDES

    NARCIS (Netherlands)

    ABEE, T; SIEBERS, A; ALTENDORF, K; KONINGS, WN

    1992-01-01

    Cells of the purple nonsulfur bacterium Rhodobacter sphaeroides express a high-affinity K+ uptake system when grown in media with low K+ concentrations. A vanadate-sensitive, K+-stimulated and Mg2+-stimulated ATPase was purified from membranes of these cells by solubilization with

  16. Color-sensitive motility and methanol release responses in Rhodobacter sphaeroides

    NARCIS (Netherlands)

    Kort, R; Crielaard, W.; Spudich, J L; Hellingwerf, K J

    Blue-light-induced repellent and demethylation responses, characteristic of behavioral adaptation, were observed in Rhodobacter sphaeroides. They were analyzed by computer-assisted motion analysis and through the release of volatile tritiated compounds from [methyl-(3)H]methionine-labeled cells,

  17. Tuberculose lymphonodale cervicale chez les enfants vaccines par ...

    African Journals Online (AJOL)

    La tuberculose ganglionnaire cervicale est une localisation extrapulmonaire relativement fréquente chez l'enfant. Elle pose essentiellement des difficultés de prévention. L'objectif de ce travail est d'étudier les particularités diagnostiques et thérapeutiques chez des enfants vaccinés par le BCG. Matériel et méthodes: Nôtre ...

  18. Les dyslipidemies et antiretroviraux chez les personnes vivant avec ...

    African Journals Online (AJOL)

    hypercholestérolémie, l'hyper LDL-cholestérolémie, l'hypo HDLcholestérolémie ont été retrouvées respectivement chez 41,4%, 23,5% et 17,4% des patients. La différence n'est pas significative entre les fréquences des troubles lipidiques chez les ...

  19. Aspects des Onychomycoses chez des patients camerounais de ...

    African Journals Online (AJOL)

    ... biologiques et évolutifs des onychomycoses chez des patients camerounais. Méthode : Il s'agit d'une étude rétrospective et descriptive menée de mars 2011 à mars 2014 dans l'unité de dermatologie de l'hôpital général de Douala (HGD), incluant des patients chez lesquels le diagnostic d'onychomycose avait été posé.

  20. Selenite exacerbates hepatic insulin resistance in mouse model of type 2 diabetes through oxidative stress-mediated JNK pathway

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jun, E-mail: hustzhj@hust.edu.cn; Xu, Gang; Bai, Zhaoshuai; Li, Kaicheng; Yan, Junyan; Li, Fen; Ma, Shuai; Xu, Huibi; Huang, Kaixun, E-mail: hxxzrf@hust.edu.cn

    2015-12-15

    Recent evidence suggests a potential pro-diabetic effect of selenite treatment in type 2 diabetics; however, the underlying mechanisms remain elusive. Here we investigated the effects and the underlying mechanisms of selenite treatment in a nongenetic mouse model of type 2 diabetes. High-fat diet (HFD)/streptozotocin (STZ)-induced diabetic mice were orally gavaged with selenite at 0.5 or 2.0 mg/kg body weight/day or vehicle for 4 weeks. High-dose selenite treatment significantly elevated fasting plasma insulin levels and insulin resistance index, in parallel with impaired glucose tolerance, insulin tolerance and pyruvate tolerance. High-dose selenite treatment also attenuated hepatic IRS1/Akt/FoxO1 signaling and pyruvate kinase gene expressions, but elevated the gene expressions of phosphoenolpyruvate carboxyl kinase (PEPCK), glucose 6-phosphatase (G6Pase), peroxisomal proliferator-activated receptor-γ coactivator 1α (PGC-1α) and selenoprotein P (SelP) in the liver. Furthermore, high-dose selenite treatment caused significant increases in MDA contents, protein carbonyl contents, and a decrease in GSH/GSSG ratio in the liver, concurrent with enhanced ASK1/MKK4/JNK signaling. Taken together, these findings suggest that high-dose selenite treatment exacerbates hepatic insulin resistance in mouse model of type 2 diabetes, at least in part through oxidative stress-mediated JNK pathway, providing new mechanistic insights into the pro-diabetic effect of selenite in type 2 diabetes. - Highlights: • Selenite exacerbates hepatic insulin resistance in HFD/STZ-induced diabetic mice. • Selenite elevates hepatic gluconeogenesis and reduces glycolysis in diabetic mice. • Selenite exacerbates hepatic oxidative stress and triggers JNK signaling pathway. • Selenite elevates hepatic selenoprotein P expression in diabetic mice.

  1. Selenite exacerbates hepatic insulin resistance in mouse model of type 2 diabetes through oxidative stress-mediated JNK pathway

    International Nuclear Information System (INIS)

    Zhou, Jun; Xu, Gang; Bai, Zhaoshuai; Li, Kaicheng; Yan, Junyan; Li, Fen; Ma, Shuai; Xu, Huibi; Huang, Kaixun

    2015-01-01

    Recent evidence suggests a potential pro-diabetic effect of selenite treatment in type 2 diabetics; however, the underlying mechanisms remain elusive. Here we investigated the effects and the underlying mechanisms of selenite treatment in a nongenetic mouse model of type 2 diabetes. High-fat diet (HFD)/streptozotocin (STZ)-induced diabetic mice were orally gavaged with selenite at 0.5 or 2.0 mg/kg body weight/day or vehicle for 4 weeks. High-dose selenite treatment significantly elevated fasting plasma insulin levels and insulin resistance index, in parallel with impaired glucose tolerance, insulin tolerance and pyruvate tolerance. High-dose selenite treatment also attenuated hepatic IRS1/Akt/FoxO1 signaling and pyruvate kinase gene expressions, but elevated the gene expressions of phosphoenolpyruvate carboxyl kinase (PEPCK), glucose 6-phosphatase (G6Pase), peroxisomal proliferator-activated receptor-γ coactivator 1α (PGC-1α) and selenoprotein P (SelP) in the liver. Furthermore, high-dose selenite treatment caused significant increases in MDA contents, protein carbonyl contents, and a decrease in GSH/GSSG ratio in the liver, concurrent with enhanced ASK1/MKK4/JNK signaling. Taken together, these findings suggest that high-dose selenite treatment exacerbates hepatic insulin resistance in mouse model of type 2 diabetes, at least in part through oxidative stress-mediated JNK pathway, providing new mechanistic insights into the pro-diabetic effect of selenite in type 2 diabetes. - Highlights: • Selenite exacerbates hepatic insulin resistance in HFD/STZ-induced diabetic mice. • Selenite elevates hepatic gluconeogenesis and reduces glycolysis in diabetic mice. • Selenite exacerbates hepatic oxidative stress and triggers JNK signaling pathway. • Selenite elevates hepatic selenoprotein P expression in diabetic mice.

  2. High Pressure Reduction of Selenite by Shewanella oneidensis MR-1

    Science.gov (United States)

    Picard, A.; Daniel, I.; Testemale, D.; Letard, I.; Bleuet, P.; Cardon, H.; Oger, P.

    2007-12-01

    High-pressure biotopes comprise cold deep-sea environments, hydrothermal vents, and deep subsurface or deep-sea sediments. The latter are less studied, due to the technical difficulties to sample at great depths without contamination. Nevertheless, microbial sulfate reduction and methanogenesis have been found to be spatially distributed in deep deep-sea sediments (1), and sulfate reduction has been shown to be actually more efficient under high hydrostatic pressure (HHP) in some sediments (2). Sulfate-reducing bacteria obtained from the Japan Sea are characterized by an increased sulfide production under pressure (3,4). Unfortunately, investigations of microbial metabolic activity as a function of pressure are extremely scarce due to the experimental difficulty of such measurements at high hydrostatic pressure. We were able to measure the reduction of selenite Se(IV) by Shewanella oneidensis MR-1 as a function of pressure, to 150 MPa using two different high-pressure reactors that allow in situ X-ray spectroscopy measurements on a synchrotron source. A first series of measurements was carried out in a low-pressure Diamond Anvil Cell (DAC) of our own design (5) at ID22 beamline at ESRF (European Synchrotron Radiation Facility); a second one was performed in an autoclave (6) at the BM30B beamline at ESRF. Selenite reduction by strain MR-17 was monitored from ambient pressure to 150 MPa over 25 hours at 30 deg C by XANES spectroscopy (X-ray Analysis of Near Edge Structure). Spectra were recorded hourly in order to quantify the evolution of the oxidation state of selenium with time. Stationary-phase bacteria were inoculated at a high concentration into fresh growth medium containing 5 or 10 M of sodium selenite and 20 mM sodium lactate. Kinetic parameters of the Se (IV) reduction by Shewanella oneidensis strain MR-1 could be extracted from the data, as a function of pressure. They show 1) that the rate constant k of the reaction is decreased by a half at high pressure

  3. Protective effects of sodium selenite on lead nitrate-induced hepatotoxicity in diabetic and non-diabetic rats.

    Science.gov (United States)

    Kalender, Suna; Apaydin, Fatma Gökçe; Baş, Hatice; Kalender, Yusuf

    2015-09-01

    In the present study, the effect of sodium selenite on lead induced toxicity was studied in Wistar rats. Sodium selenite and lead nitrate were administered orally for 28 days to streptozotocin induced diabetic and non-diabetic rats. Eight groups of rats were used in the study: control, sodium selenite, lead nitrate, lead nitrate+sodium selenite, streptozotocin-induced diabetic-control, diabetic-sodium selenite, diabetic-lead nitrate, diabetic-lead nitrate+sodium selenite groups. Serum biochemical parameters, lipid peroxidation, antioxidant enzymes and histopathological changes in liver tissues were investigated in all groups. There were statistically significant changes in liver function tests, antioxidant enzyme activities and lipid peroxidation levels in lead nitrate and sodium selenite+lead nitrate treated groups, also in diabetic and non-diabetic groups. Furthermore, histopathological alterations were demonstrated in same groups. In the present study we found that sodium selenite treatment did not show completely protective effect on diabetes mellitus caused damages, but diabetic rats are more susceptible to lead toxicity than non-diabetic rats. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Uptake and Distribution of Added Selenite and Selenate by Barley and Red Clover as Influenced by Sulphur

    DEFF Research Database (Denmark)

    Nielsen, Gunnar Gissel

    1973-01-01

    The uptake of added Se from selenite and selenate by barley and red clover was investigated in a pot experiment. Much more of selenate than of selenite was taken up but the Se concentrations in the plants declined more with time when selenate was the source. Increasing sulphate addition to the soil...

  5. In situ time-resolved X-ray near-edge absorption spectroscopy of selenite reduction by siderite

    International Nuclear Information System (INIS)

    Badaut, V.; Schlegel, M.L.; Descostes, M.; Moutiers, G.

    2012-01-01

    The reduction oxidation-reaction between aqueous selenite (SeO 3 2- ) and siderite (FeCO 3 (s)) was monitored by in situ, time-resolved X-ray absorption near-edge structure (XANES) spectroscopy at the selenium K edge in a controlled electrochemical environment. Spectral evolutions showed that more than 60% of selenite was reduced at the siderite surface after 20 h of experiment, at which time the reaction was still incomplete. Fitting of XANES spectra by linear combination of reference spectra showed that selenite reaction with siderite is essentially a two-step process, selenite ions being immobilized on siderite surface prior to their reduction. A kinetic model of the reduction step is proposed, allowing to identify the specific contribution of surface reduction. These results have strong implications for the retention of selenite by corrosion products in nuclear waste repositories and in a larger extent for the fate of selenium in the environment. (authors)

  6. Selenopeptides and elemental selenium in Thunbergia alata after exposure to selenite: quantification method for elemental selenium.

    Science.gov (United States)

    Aborode, Fatai Adigun; Raab, Andrea; Foster, Simon; Lombi, Enzo; Maher, William; Krupp, Eva M; Feldmann, Joerg

    2015-07-01

    Three month old Thunbergia alata were exposed for 13 days to 10 μM selenite to determine the biotransformation of selenite in their roots. Selenium in formic acid extracts (80 ± 3%) was present as selenopeptides with Se-S bonds and selenium-PC complexes (selenocysteinyl-2-3-dihydroxypropionyl-glutathione, seleno-phytochelatin2, seleno-di-glutathione). An analytical method using HPLC-ICPMS to detect and quantify elemental selenium in roots of T. alata plants using sodium sulfite to quantitatively transform elemental selenium to selenosulfate was also developed. Elemental selenium was determined as 18 ± 4% of the total selenium in the roots which was equivalent to the selenium not extracted using formic acid extraction. The results are in an agreement with the XAS measurements of the exposed roots which showed no occurrence of selenite or selenate but a mixture of selenocysteine and elemental selenium.

  7. The microbial impact on the sorption behaviour of selenite in an acidic, nutrient-poor boreal bog

    International Nuclear Information System (INIS)

    Lusa, M.; Bomberg, M.; Aromaa, H.; Knuutinen, J.; Lehto, J.

    2015-01-01

    79 Se is among the most important long lived radionuclides in spent nuclear fuel and selenite, SeO 3 2− , is its typical form in intermediate redox potential. The sorption behaviour of selenite and the bacterial impact on the selenite sorption in a 7-m-deep profile of a nutrient-poor boreal bog was studied using batch sorption experiments. The batch distribution coefficient (K d ) values of selenite decreased as a function of sampling depth and highest K d values, 6600 L/kg dry weight (DW), were observed in the surface moss and the lowest in the bottom clay at 1700 L/kg DW. The overall maximum sorption was observed at pH between 3 and 4 and the K d values were significantly higher in unsterilized compared to sterilized samples. The removal of selenite from solution by Pseudomonas sp., Burkholderia sp., Rhodococcus sp. and Paenibacillus sp. strains isolated from the bog was affected by incubation temperature and time. In addition, the incubation of sterilized surface moss, subsurface peat and gyttja samples with added bacteria effectively removed selenite from the solution and on average 65% of selenite was removed when Pseudomonas sp. or Burkholderia sp. strains were used. Our results demonstrate the important role of bacteria for the removal of selenite from the solution phase in the bog environment, having a high organic matter content and a low pH. - Highlights: • Sterilization of bog samples inhibited the SeO 3 2− removal from simulated bog water. • Bacteria isolated from the bog samples removed selenite from the solution. • Bacteria affect the removal of SeO 3 2− from the solution in a nutrient-poor bog. • Selenite is reduced by the bacteria present in the bog both under oxic and anoxic conditions within the different microniches therein. • That is a prerequisite to read the record of the deformational history in metamorphic rocks

  8. Photoresponses of the purple nonsulfur bacteria Rhodospirillum centenum and Rhodobacter sphaeroides.

    OpenAIRE

    Sackett, M J; Armitage, J P; Sherwood, E E; Pitta, T P

    1997-01-01

    We have measured the photoresponse of two purple nonsulfur bacteria, Rhodobacter sphaeroides and Rhodospirillum centenum, under defined conditions in a light beam propagating at 90 degrees to the optical axis of the microscope. This beam presented cells with a steep gradient of intensity perpendicular to the direction of propagation and a shallow gradient in the direction of light propagation. R. centenum, a species that reverses to change direction, accumulated in the light beam, as expected...

  9. Polarographic behaviour and determination of selenite and tellurite in simple solutions or in a binary mixture

    International Nuclear Information System (INIS)

    Hassan, A.

    1991-01-01

    The polarographic behaviour of simple solutions of selenite and tellurite in 1 M ammonium salts of formate, acetate, tartrate, oxalate, and benzoate solutions in absence and in presence of Triton X-100 as a maximum suppressor and a temperature of 25 O C has been investigated. Schemes for the mechanism of reductions occuring at the DME have been deduced. A method for analytical determination of selenite and tellurite in simple solutions as well as in a binary mixture in the presence of 4-14 . 10 -3 % Triton X-100 is reported. (author)

  10. The thermodynamics of arsenates, selenites, and sulfates in the oxidation zone of sulfide ores. XI. Solubility of synthetic chalcomenite analog and zinc selenite at 25°C

    Science.gov (United States)

    Charykova, M. V.; Krivovichev, V. G.; Ivanova, N. M.; Semenova, V. V.

    2015-12-01

    The aim of this study is the synthesis of CuSeO3·2H2O (chalcomenite analog), ZnSeO3·2H2O, and ZnSeO3·H2O and the investigation of their solubility in water. CuSeO3·2H2O has been synthesized from solutions of Cu nitrate and Na selenite, while Zn selenites were synthesized from solutions of Zn nitrate and Na selenite. The samples obtained have been examined with X-ray diffraction and infrared and Raman spectroscopy. The solubility has been determined using the isothermal saturation method in ampoules at 25°C. The solubility has been calculated using the Geochemist's Workbench (GMB 9.0) software package. Solubility products have been calculated for CuSeO3·2H2O (10-10.63), ZnSeO3·2H2O (10-8.35), and ZnSeO3·H2O (10-7.96). The database used comprises thermodynamic characteristics of 46 elements, 47 base particles, 48 redox pairs, 551 particles in solution, and 624 solid phases. The Eh-pH diagrams of the Zn-Se-H2O and Cu-Se-H2O systems were plotted for the average contents of these elements in underground water in oxidation zones of sulfide deposits.

  11. Experimental Study and modelling of the Sorption of Selenite and Europium Onto Smectite and Illite Clays

    International Nuclear Information System (INIS)

    Missana, T.; Alonso, U.; Garcia-Gutierrez, M.

    2009-01-01

    This study provides a large set of experimental selenite sorption data for pure smectite and illite. Similar sorption behavior existed in both clays: linear within a large range of the Se concentrations investigated and independent of ionic strength. Selenite sorption was also analysed in the illite/smectite system with the clays mixed in two different proportions. The objective of the study was to provide the simplest model possible to fit the experimental data, a model also capable of describing selenite sorption in binary illite/smectite clay systems. Selenite sorption data were modeled using both a one-and a two-site non-electrostatic model that took into account the formation of two complexes at the edge sites of the clay. The complexation constants obtained by fitting sorption data of the individual minerals were incorporated into a model to predict the adsorption of selenium in the illite/ smectite mixtures; the models predictions were consistent with the experimental adsorption data. (Author) 42 refs

  12. Experimental Study and modelling of the Sorption of Selenite and Europium Onto Smectite and Illite Clays

    Energy Technology Data Exchange (ETDEWEB)

    Missana, T.; Alonso, U.; Garcia-Gutierrez, M.

    2009-10-12

    This study provides a large set of experimental selenite sorption data for pure smectite and illite. Similar sorption behavior existed in both clays: linear within a large range of the Se concentrations investigated and independent of ionic strength. Selenite sorption was also analysed in the illite/smectite system with the clays mixed in two different proportions. The objective of the study was to provide the simplest model possible to fit the experimental data, a model also capable of describing selenite sorption in binary illite/smectite clay systems. Selenite sorption data were modeled using both a one-and a two-site non-electrostatic model that took into account the formation of two complexes at the edge sites of the clay. The complexation constants obtained by fitting sorption data of the individual minerals were incorporated into a model to predict the adsorption of selenium in the illite/ smectite mixtures; the models predictions were consistent with the experimental adsorption data. (Author) 42 refs.

  13. Effect of sodium selenite on bone repair in tibiae of irradiated rats

    International Nuclear Information System (INIS)

    Rocha, Anna Silvia Setti da; Ramos-Perez, Flavia Maria de Moraes; Boscolo, Frab Norberto; Almeida, Solange Maria; Manzi, Flavio Ricardo; Chicareli, Mariliani

    2009-01-01

    This study evaluated the radioprotective effect of sodium selenite on the bone repair process in tibiae of female rats. For such purpose, 100 female Wistar rats (Rattus norvegicus, albinus) were randomly assigned to 4 groups (n=25), according to the treatment received: administration of distilled water (control); administration of sodium selenite; gamma radiation; and administration of sodium selenite plus gamma radiation. A bone defect was prepared on both tibiae of all animals. Three days after surgery, the gamma radiation and selenium/ gamma radiation groups received 8 Gy gamma rays on the lower limbs. Five animals per group were sacrificed 7, 14, 21, 28 days after surgery for evaluation of the repair process by bone volumetric density analysis. The 5 animals remaining in each group were sacrificed 45 days postoperatively for examination of the mature bone by scanning electron microscopy. Based on all analyzed parameters, the results of the present study suggest that sodium selenite exerted a radioprotective effect in the bone repair of tibia of irradiated rats. (author)

  14. Experimental study and modelling of selenite sorption onto illite and smectite clays.

    Science.gov (United States)

    Missana, T; Alonso, U; García-Gutiérrez, M

    2009-06-15

    This study provides a large set of experimental selenite sorption data for pure smectite and illite. Similar sorption behavior existed in both clays: linear within a large range of the Se concentrations investigated (from 1x10(-10) to 1x10(-3) M); and independent of ionic strength. Selenite sorption was also analysed in the illite/smectite system with the clays mixed in two different proportions, as follows: (a) 30% illite-70% smectite and (b) 43% illite-57% smectite. The objective of the study was to provide the simplest model possible to fit the experimental data, a model also capable of describing selenite sorption in binary illite/smectite clay systems. Selenite sorption data, separately obtained in the single mineral systems, were modeled using both a one- and a two-site non-electrostatic model that took into account the formation of two complexes at the edge sites of the clay. Although the use of a two-site model slightly improved the fit of data at a pH below 4, the simpler one-site model reproduced satisfactorily all the sorption data from pH 3 to 8. The complexation constants obtained by fitting sorption data of the individual minerals were incorporated into a model to predict the adsorption of selenium in the illite/smectite mixtures; the model's predictions were consistent with the experimental adsorption data.

  15. Mechanisms regulating the reduction of selenite by aerobic gram (+) and (-) bacteria

    International Nuclear Information System (INIS)

    Garbisu, C.; Ishii, Takahisa; Yee, B.C.; Carlson, D.E.; Buchanan, B.B.; Leighton, T.; Smith, N.R.; Yee, A.

    1995-01-01

    Toxic species of selenium are pollutants found in agricultural and oil refinery wastestreams. Selenium contamination is particularly problematic in areas that have seleniferous subsurface geology, such as the central valley of California. The authors are developed a bacterial treatment system to mitigate selenium-contaminated wastestreams using Bacillus subtilis and Pseudomonas fluorescens, respectively, as model gram (+) and (-) soil bacteria. They have found that, during growth, both organisms reduce selenite, a major soluble toxic species, to red elemental selenium--an insoluble product generally regarded as nontoxic. In both cases, reduction depended on growth substrate and was effected by an inducible system that effectively removed selenite at concentrations typical of polluted sites--i.e., 50 to 300 microg/L. The bacteria studied differed in one respect: when grown in medium supplemented with nitrate or sulfate, the ability of P. fluorescens to remediate selenite was enhanced, whereas that of B. subtilis was unchanged. Current efforts are being directed toward understanding the biochemical mechanism(s) of detoxification and determining whether bacteria occurring in polluted environments such as soils and sludge systems are capable of selenite remediation

  16. The intensity of tyrosine nitration is associated with selenite and selenate toxicity in Brassica juncea L.

    Science.gov (United States)

    Molnár, Árpád; Feigl, Gábor; Trifán, Vanda; Ördög, Attila; Szőllősi, Réka; Erdei, László; Kolbert, Zsuzsanna

    2018-01-01

    Selenium phytotoxicity involves processes like reactive nitrogen species overproduction and nitrosative protein modifications. This study evaluates the toxicity of two selenium forms (selenite and selenate at 0µM, 20µM, 50µM and 100µM concentrations) and its correlation with protein tyrosine nitration in the organs of hydroponically grown Indian mustard (Brassica juncea L.). Selenate treatment resulted in large selenium accumulation in both Brassica organs, while selenite showed slight root-to-shoot translocation resulting in a much lower selenium accumulation in the shoot. Shoot and root growth inhibition and cell viability loss revealed that Brassica tolerates selenate better than selenite. Results also show that relative high amounts of selenium are able to accumulate in Brassica leaves without obvious visible symptoms such as chlorosis or necrosis. The more severe phytotoxicity of selenite was accompanied by more intense protein tyrosine nitration as well as alterations in nitration pattern suggesting a correlation between the degree of Se forms-induced toxicities and nitroproteome size, composition in Brassica organs. These results imply the possibility of considering protein tyrosine nitration as novel biomarker of selenium phytotoxicity, which could help the evaluation of asymptomatic selenium stress of plants. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Reduction of selenite by Azospirillum brasilense with the formation of selenium nanoparticles.

    Science.gov (United States)

    Tugarova, Anna V; Vetchinkina, Elena P; Loshchinina, Ekaterina A; Burov, Andrei M; Nikitina, Valentina E; Kamnev, Alexander A

    2014-10-01

    The ability to reduce selenite (SeO(3)(2-)) ions with the formation of selenium nanoparticles was demonstrated in Azospirillum brasilense for the first time. The influence of selenite ions on the growth of A. brasilense Sp7 and Sp245, two widely studied wild-type strains, was investigated. Growth of cultures on both liquid and solid (2 % agar) media in the presence of SeO(3)(2-) was found to be accompanied by the appearance of the typical red colouration. By means of transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS) and X-ray fluorescence analysis (XFA), intracellular accumulation of elementary selenium in the form of nanoparticles (50 to 400 nm in diameter) was demonstrated for both strains. The proposed mechanism of selenite-to-selenium (0) reduction could involve SeO(3)(2-) in the denitrification process, which has been well studied in azospirilla, rather than a selenite detoxification strategy. The results obtained point to the possibility of using Azospirillum strains as endophytic or rhizospheric bacteria to assist phytoremediation of, and cereal cultivation on, selenium-contaminated soils. The ability of A. brasilense to synthesise selenium nanoparticles may be of interest to nanobiotechnology for "green synthesis" of bioavailable amorphous red selenium nanostructures.

  18. Effect of sodium selenite on bone repair in tibiae of irradiated rats

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Anna Silvia Setti da [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR, (Brazil). Dept. of Physics; Ramos-Perez, Flavia Maria de Moraes; Boscolo, Frab Norberto; Almeida, Solange Maria [Universidade Estadual de Campinas (UNICAMP), Piracicaba, SP (Brazil). Piracicaba Dental School. Dept. of Oral Diagnosis], e-mail: flaviamaria@fop.unicamp.br; Manzi, Flavio Ricardo [Pontifical Catholic University of Minas Gerais (PUC-MG), Belo Horizonte, MG (Brazil). Dept. of Stomatology; Chicareli, Mariliani [State Univ. of Maringa, PR (Brazil). Dept. of Oral Diagnosis

    2009-07-01

    This study evaluated the radioprotective effect of sodium selenite on the bone repair process in tibiae of female rats. For such purpose, 100 female Wistar rats (Rattus norvegicus, albinus) were randomly assigned to 4 groups (n=25), according to the treatment received: administration of distilled water (control); administration of sodium selenite; gamma radiation; and administration of sodium selenite plus gamma radiation. A bone defect was prepared on both tibiae of all animals. Three days after surgery, the gamma radiation and selenium/ gamma radiation groups received 8 Gy gamma rays on the lower limbs. Five animals per group were sacrificed 7, 14, 21, 28 days after surgery for evaluation of the repair process by bone volumetric density analysis. The 5 animals remaining in each group were sacrificed 45 days postoperatively for examination of the mature bone by scanning electron microscopy. Based on all analyzed parameters, the results of the present study suggest that sodium selenite exerted a radioprotective effect in the bone repair of tibia of irradiated rats. (author)

  19. Deletion of thioredoxin reductase and effects of selenite and selenate toxicity in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Christopher J Boehler

    Full Text Available Thioredoxin reductase-1 (TRXR-1 is the sole selenoprotein in C. elegans, and selenite is a substrate for thioredoxin reductase, so TRXR-1 may play a role in metabolism of selenium (Se to toxic forms. To study the role of TRXR in Se toxicity, we cultured C. elegans with deletions of trxr-1, trxr-2, and both in axenic media with increasing concentrations of inorganic Se. Wild-type C. elegans cultured for 12 days in Se-deficient axenic media grow and reproduce equivalent to Se-supplemented media. Supplementation with 0-2 mM Se as selenite results in inverse, sigmoidal response curves with an LC50 of 0.20 mM Se, due to impaired growth rather than reproduction. Deletion of trxr-1, trxr-2 or both does not modulate growth or Se toxicity in C. elegans grown axenically, and (75Se labeling showed that TRXR-1 arises from the trxr-1 gene and not from bacterial genes. Se response curves for selenide (LC50 0.23 mM Se were identical to selenite, but selenate was 1/4(th as toxic (LC50 0.95 mM Se as selenite and not modulated by TRXR deletion. These nutritional and genetic studies in axenic media show that Se and TRXR are not essential for C. elegans, and that TRXR alone is not essential for metabolism of inorganic Se to toxic species.

  20. Tabagisme et dysfonction erectile chez les personnes vivant avec le ...

    African Journals Online (AJOL)

    La dysfonction erectile (DE) est un probleme de sante publique qui altere la qualite de vie des patients. Chez les personnes infectees par le VIH, le tabagisme en association ii d'autres facteurs pourrait accroitre le risque de survenue de ce trouble. L'objectif de cette etude est de determiner la prevalence de laDE, les ...

  1. Depression chez l'hemiplegique vasculaire a Brazzaville | Ossou ...

    African Journals Online (AJOL)

    L'évolution à 6 mois n'a pas été favorable chez 65,7 % des patients. ... Sa prise en charge permettrait assurément d'améliorer la qualité de vie des patients, ... The management of post-stroke depression certainly improves the quality of life of ...

  2. Inobservance therapeutique aux anti-retroviraux chez les personnes ...

    African Journals Online (AJOL)

    Buts : Rechercher les facteurs psychologiques ou psychosociaux responsables de l'inobservance thérapeutique (IBT) aux antiretroviraux (ARV) Méthodologie : Il s'agit d'une étude transversale sur 06 mois (mai - octobre 2008) menée au centre de promotion sociale à Lomé chez les personnes vivant avec le VIH (PVVIH) ...

  3. Risque de transmission sexuelle chez les personnes vivant avec le ...

    African Journals Online (AJOL)

    Contexte : Depuis 1996, les traitements du sida ont permis de changer le visage de la maladie. Un traitement efficace ... Conclusion : Cette étude a décrit que le risque de transmission sexuelle des infections sexuellement transmissibles (IST) existe chez les PVVIH à cause des rapports sexuels à risque. D'autres études ...

  4. Efficacite de la bitherapie raltegravir-etravirine chez les ...

    African Journals Online (AJOL)

    Efficacite de la bitherapie raltegravir-etravirine chez les immunodeprimes au VIH. D Traore, A Simon, N Sawadogo, S.A. Coulibaly, D.S. Sow, A.S. Kaya, M Dembélé, A.K. Traoré, H.A. Traoré, S Herson ...

  5. Effects Of Erdosteine On Oxidative-Antioxidative Equilibrium And On Cataract Formation In Rat Pups With Selenite-Induced Cataract

    OpenAIRE

    Kılıç, Adil; Selek, Şahbettin; Erel, Özcan

    2015-01-01

    Aim: To investigate whether erdosteine supplementation following selenite exposure affects oxidant-antioxidant equilibrium and prevents cataract formation in rat pups. Methods: Thirty-nine Wistar-albino rat pups were divided into 3 groups. In Group 1 (n=16) only s.c saline was injected. In Group 2 (n=10) subcutaneous (s.c.) sodium selenite (30 nmol / g body weight) was injected on postpartum day 10. In Group 3 (n=13) s.c. sodium selenite (30 nmol/g body weight) were injected on postpartum day...

  6. L’amor humanus chez Marsile Ficin

    Directory of Open Access Journals (Sweden)

    Laurence Boulègue

    2010-12-01

    Full Text Available Les éditions et études du Commentaire sur le Banquet de Platon, ou De amore, de Marsile Ficin ont mis en évidence que la conception de Vamor humanus chez l'humaniste florentin, inspirée certes des définitions du Banquet de Platon, était étroitement liée aux conceptions néoplatoniciennes héritées de Plotin. Néanmoins, l'interprétation du texte de Platon et les développements de ses successeurs ne sauraient à eux seuls rendre compte de la définition ficinienne, notamment dans son lien avec la notion, romaine, de la fascinatio. La philosophie et la poésie romaines des passions offrent une analyse du sentiment amoureux dont les échos sont sensibles dans le texte même du Commentaire. En effet, l'exposé des passions qu'offre le livre IV des Tusculanes a sans aucun doute fourni à Ficin les caractéristiques et la définition du « mauvais amour », dont l'évocation n'est pas étrangère aux motifs poétiques tels qu'on peut les trouver, par exemple, dans la poésie ovidienne à propos du mythe de Narcisse, dont Ficin se souvient. Si Cicéron soulignait, au début du livre IV des Tusculanes, la tension qui existait entre l'anthropologie platonicienne et la théorie des passions stoïcienne, il ne la résolvait pas. Ficin, lui, réalise cette articulation grâce à la hiérarchisation néoplatonicienne des différents amours et peut ainsi affirmer l'existence d'un bon amour. Mais un tel amor humanus, qui est amour philopédique, destiné à l'élévation divine ou voué à s'affaisser jusqu'à la concupiscence bestiale, ne peut être qu'un moment dans le processus proposé par Ficin, un point de fragile équilibre, intenable.

  7. Hypocholesterolemic Response to Karaya Saponin and Rhodobacter capsulatus in Broiler Chickens

    OpenAIRE

    Afrose, Sadia; Hossain, Md. Sharoare; Maki, Takaaki; Tsujii, Hirotada

    2010-01-01

    Dietary karaya saponin and Rhodobacter capsulatus (R. capsulatus) are known to have hypocholesterolemic actions, as reported in our previous studies. This study examined possible synergistic hypocholesterolemic effects of karaya saponin and R. capsulatus in broilers. A total of 150 broilers were allocated into 10 treatments: control, saponin 25 mg, saponin 50 mg, saponin 75 mg, saponin 25 mg+R. capsulatus 0.2 g, saponin 25 mg+R. capsulatus 0.4 g, saponin 50 mg+R. capsulatus 0.2 g, saponin 50 ...

  8. DNA sequence analysis of the photosynthesis region of Rhodobacter sphaeroides 2.4.1T

    OpenAIRE

    Choudhary, M.; Kaplan, Samuel

    2000-01-01

    This paper describes the DNA sequence of the photosynthesis region of Rhodobacter sphaeroides 2.4.1T. The photosynthesis gene cluster is located within a ~73 kb AseI genomic DNA fragment containing the puf, puhA, cycA and puc operons. A total of 65 open reading frames (ORFs) have been identified, of which 61 showed significant similarity to genes/proteins of other organisms while only four did not reveal any significant sequence similarity to any gene/protein sequences in the database. The da...

  9. Mechanisms of inhibition of zinc-finger transcription factors by selenium compounds ebselen and selenite.

    Science.gov (United States)

    Larabee, Jason L; Hocker, James R; Hanas, Jay S

    2009-03-01

    The anti-inflammatory selenium compounds, ebselen (2-phenyl-1,2-benzisoselenazol-3[2H]-one) and selenite, were found to alter the DNA binding mechanisms and structures of cysteine-rich zinc-finger transcription factors. As assayed by DNase I protection, DNA binding by TFIIIA (transcription factor IIIA, prototypical Cys(2)His(2) zinc finger protein), was inhibited by micromolar amounts of ebselen. In a gel shift assay, ebselen inhibited the Cys(2)His(2) zinc finger-containing DNA binding domain (DBD) of the NF-kappaB mediated transcription factor Sp1. Ebselen also inhibited DNA binding by the p50 subunit of the pro-inflammatory Cys-containing NF-kappaB transcription factor. Electrospray ionization mass spectrometry (ESI-MS) was utilized to elucidate mechanisms of chemical interaction between ebselen and a zinc-bound Cys(2)His(2) zinc finger polypeptide modeled after the third finger of Sp1 (Sp1-3). Exposing Sp1-3 to micromolar amounts of ebselen resulted in Zn(2+) release from this peptide and the formation of a disulfide bond by oxidation of zinc finger SH groups, the likely mechanism for DNA binding inhibition. Selenite was shown by ESI-MS to also eject zinc from Sp1-3 as well as induce disulfide bond formation through SH oxidation. The selenite-dependent inhibition/oxidation mechanism differed from that of ebselen by inducing the formation of a stable selenotrisulfide bond. Selenite-induced selenotrisulfide formation was dependent upon the structure of the Cys(2)His(2) zinc finger as alteration in the finger structure enhanced this reaction as well as selenite-dependent zinc release. Ebselen and selenite-dependent inhibition/oxidation of Cys-rich zinc finger proteins, with concomitant release of zinc and finger structural changes, points to mechanisms at the atomic and protein level for selenium-induced alterations in Cys-rich proteins, and possible amelioration of certain inflammatory, neurodegenerative, and oncogenic responses.

  10. Effects of sodium selenite supplementation on lead nitrate-induced oxidative stress in lung tissues of diabetic and non-diabetic rats

    OpenAIRE

    APAYDIN, Fatma; KALENDER, Suna; DEMİR, Filiz; BAŞ, Hatice

    2014-01-01

    In this study, diabetic and non-diabetic male rats were given to sodium selenite, lead nitrate and sodium selenite plus lead nitrate through gavage. At the end of the 4th week, lipid peroxidation and antioxidant enzyme activities was investigated compared to control group. No significant differences were observed between control and sodium selenite treated groups. By the end of the fourth week, lead nitrate led to increase the levels of MDA, and decrease in antioxidant activities compared wit...

  11. Two dimensional crystals of LH2 light-harvesting complexes from Ectothiorhodospira sp. and Rhodobacter capsulatus investigated by electron microscopy

    NARCIS (Netherlands)

    Oling, Frank; Boekema, EJ; deZarate, IO; Visschers, R; vanGrondelle, R; Keegstra, W; Brisson, A; Picorel, R

    1996-01-01

    Two-dimensional crystals of LH2 (B800-850) light-harvesting complexes from Ectothiorhodospira sp, and Rhodobacter capsulatus were obtained by reconstitution of purified protein into phospholipid vesicles and characterized by electron microscopy. The size of the crystals was up to several

  12. A new pathway for transmembrane electron transfer in photosynthetic reaction centers of Rhodobacter sphaeroides not involving the excited special pair.

    NARCIS (Netherlands)

    van Brederode, M.E.; Jones, M.R.; van Mourik, F.; van Stokkum, I.H.M.; van Grondelle, R.

    1997-01-01

    It is generally accepted that electron transfer in bacterial photosynthesis is driven by the first singlet excited state of a special pair of bacteriochlorophylls (P*). We have examined the first steps of electron transfer in a mutant of the Rhodobacter sphaeroides reaction center in which charge

  13. A new pathway for transmembrane electron transfer in photosyntetic reaction centers of Rhodobacter sphaeroides not involving the excited special pair.

    NARCIS (Netherlands)

    van Brederode, M.E.; Jones, M.R.; van Mourik, F.; van Stokkum, I.H.M.; van Grondelle, R.

    1997-01-01

    It is generally accepted that electron transfer in bacterial photosynthesis is driven by the first singlet excited state of a special pair of bacteriochlorophylls (P*). We have examined the first steps of electron transfer in a mutant of the Rhodobacter sphaeroides reaction center in which charge

  14. Direct Visualization of Exciton Reequilibration in the LH1 and LH2 Complexes of Rhodobacter sphaeroides by Multipulse Spectroscopy

    NARCIS (Netherlands)

    Cohen Stuart, T.A.; Vengris, M.; Novoderezhkin, V.I.; Cogdell, R.J.; Hunter, C.N.; van Grondelle, R.

    2011-01-01

    The dynamics of the excited states of the light-harvesting complexes LH1 and LH2 of Rhodobacter sphaeroides are governed, mainly, by the excitonic nature of these ring-systems. In a pump-dump-probe experiment, the first pulse promotes LH1 or LH2 to its excited state and the second pulse dumps a

  15. Hydrogen production by using Rhodobacter capsulatus mutants with genetically modified electron transfer chains

    Energy Technology Data Exchange (ETDEWEB)

    OEztuerk, Yavuz; Yuecel, Meral; Guenduez, Ufuk [Department of Biology, Middle East Technical University, Ankara (Turkey); Daldal, Fevzi [Department of Biology, Plant Science Institute, University of Pennsylvania, Philadelphia, PA 19104-6018 (United States); Mandaci, Sevnur [TUEBITAK Research Institute for Genetic Engineering and Biotechnology, Gebze Kocaeli 41470 (Turkey); Tuerker, Lemi [Department of Chemistry, Middle East Technical University, Ankara (Turkey); Eroglu, Inci [Department of Chemical Engineering, Middle East Technical University, Ankara (Turkey)

    2006-09-15

    In Rhodobacter capsulatus excess reducing equivalents generated by organic acid oxidation is consumed to reduce protons into hydrogen by the activity of nitrogenase. Nitrogenase serves as a redox-balancing tool and is activated by the RegB/RegA global regulatory system during photosynthetic growth. The terminal cytochrome cbb{sub 3} oxidase and the redox state of the cyclic photosynthetic electron transfer chain serve redox signaling to the RegB/RegA regulatory systems in Rhodobacter. In this study, hydrogen production of various R. capsulatus strains harboring the genetically modified electron carrier cytochromes or lacking the cyt cbb{sub 3} oxidase or the quinol oxidase were compared with the wild type. The results indicated that hydrogen production of mutant strains with modified electron carrier cytochromes decreased 3- to 4-fold, but the rate of hydrogen production increased significantly in a cbb{sub 3}{sup -} mutant. Moreover, hydrogen production efficiency of various R. capsulatus strains further increased by inactivation of uptake hydrogenase genes. (author)

  16. Perception urbaine, distraction et stratification chez Benjamin, Eisenstein et Vertov

    OpenAIRE

    Rousse, Pascal

    2008-01-01

    La ville à l’écran est le substrat imaginaire et historique du cinéma. Mais le cinéma, burlesque et soviétique, transforme ce contexte tout en constituant sa mémoire. Walter Benjamin inaugura cette problématique avec la notion de « distraction », liant architecture et cinéma sur le fond du paradigme de la stratification de l’appareil psychique chez Freud.

  17. In vitro uptake of 75Se-selenite by lens of young and adult rats

    International Nuclear Information System (INIS)

    Sladkova, J.; Ostadalova, I.; Babicky, A.; Obenberger, J.

    1988-01-01

    The uptake was observed of 75 Se-selenite by the lens in Wistar strain rats in adult animals, in 17-day old rats kept with their mothers and in prematurely weaned rats. Also measured was the excretion of 75 Se by the lens of young and adult rats following incubation in the medium with radioselenium. The metabolites were analysed which were discharged by the lens containing 75 Se. In Brattleboro rats the uptake of 75 Se-selenite was also measured by the lens in young and adult rats. The uptake of 75 Se-selenite by the lens in young Wistar rats was found to be 1.6 times higher than by the lens of adult rats and the time course of the radioselenium uptake was slightly different. In the lens of prematurely weaned rats no significant difference was found in the uptake of radioselenium after 4 hours as compared with rats of the same age kept with their mothers. In homozygous Brattleboro rats, a higher uptake of 75 Se-selenite was found as compared with both young and adult heterozygous rats. The time course and the quantity of 75 Se efflux from the lens of young and adult Wistar rats differed significantly after 0.5 hour of pre-incubation. From metabolites containing 75 Se excreted by the lens following preincubation, glutathione selenotrisulfide and a not yet accurately determined fraction with a large share of radioactivity were isolated. The stated results provide yet more proof that selenium cataract is a manifestation of the ontogenic dependence of selenium metabolism in the lens and in the entire organism. (author). 4 tabs., 30 refs

  18. Determination of glutathione in apoptotic SMMC-7221 cells induced by xylitol selenite using capillary electrophoresis.

    Science.gov (United States)

    Wu, Xue; Cao, Yu; Zhang, Jian; Lei, Ming; Deng, Xiaojie; Zahid, Kashif Rafiq; Liu, Yanli; Liu, Ke; Yang, Jihong; Xiong, Guomei; Yao, Hanchao; Qi, Chao

    2016-05-01

    To determine the glutathione (GSH) content in a human hepatoma cell line (SMMC-7221) treated with xylitol/selenite, providing a part of an investigation of its anti-cancer mechanisms. The nuclei of SMMC-7221 cells were stained with Hoechst 33258 in an apoptosis assay, and their morphology subsequently changed from circular to crescent shape. The calibration curve (r(2) = 0.992) was established, and GSH content markedly decreased after treated with 0.5 and 1 mg xylitol/selenite l(-1) for 12, 36 and 60 h (12 h: from 95.57 ± 19.57 to 29.09 ± 7.74 and 24.27 ± 11.15; 36 h: from 70.73 ± 11.35 to 19.54 ± 6.39 and 9.35 ± 6.69; 60 h: from 72.63 ± 16.94 to 7.432 ± 3.84 and 0). The depletion rate of GSH was more related to the concentration of xylitol/selenite than the treatment time (from 69.95 ± 1.87 to 100 % vs. 0.22 ± 0.2 to 100 %). Xylitol/selenite is a promising anti-cancer drug to induce apoptosis in SMMC-7221 cells. It may regulate the apoptosis through the co-action of multiple mechanisms related to GSH depletion.

  19. Relationship between blood-retinal barrier development and formation of selenite nuclear cataract in rat

    Directory of Open Access Journals (Sweden)

    Ping Lu

    2017-12-01

    Full Text Available AIM: To investigate the relationship between development of blood-retinal barrier and formation of selenite nuclear cataract in rat. METHODS: Activity of GPx, MDA level in lens and selenium content in the eyeballs of different ages rats were determined. Besides, lanthanum hydroxide \\〖La(OH3\\〗 tracer method was used to detect development status of blood-retina barrier at different ages. RESULTS: The result showed that the enzyme activity of GPx was highest in young rats before open eyes, but then decreased gradually with age. Distribution of La(OH3 in retinal pigment epithelial layer of 20-day-old rats was significantly less than 11-day-old rats. Injecting sodium selenite to 9-day-old rats, lanthanum hydroxide increased obviously and extended to the inner layers of the retina after 48h, and the retinal pigment epithelial layer was damaged seriously; while injecting sodium selenite to 18-day-old rats with the same dose, number of lanthanum hydroxide decreased significantly and did not extend to the inner layer after 48h.Before opening eyes, the content of MDA in the lens of rats was the highest, and decreased significantly after opening eyes. The Se group was 5 times as that of the control group. Besides, in these groups of rats, selenium content in the eyeballs and MDA level in the lens were in agreement with the change of La(OH3 distribution. CONCLUSION: These results indicated that antioxidant capacity in the eyelid unopened rats is not the main reason for selenite induced cataract formation. The real reason is that blood-retina barrier development is not mature in the eyelid unopened rats.

  20. Potassium vanadium selenite, K(VO2)3(SeO3)2

    International Nuclear Information System (INIS)

    Harrison, W.T.A.; Dussack, L.L.; Jacobson, A.J.

    1995-01-01

    The hydrothermal synthesis and single-crystal structure of potassium vanadium(V) selenite, K(VO 2 ) 3 (SeO 3 ) 2 , are reported. K(VO 2 ) 3 (SeO 3 ) 2 is a layered phase based on a hexagonal tungsten-oxide-like array of corner-sharing VO 6 octahedra capped by Se atoms, and is isostructural with NH 4 (VO 2 ) 3 (SeO 3 ) 2 . (orig.)

  1. Acute selenium toxicity in lambs following intramuscular injection of sodium selenite

    Energy Technology Data Exchange (ETDEWEB)

    Caravaggi, C; Clark, F L; Jackson, A R.B.

    1970-01-01

    The LD50 in lambs from a farm where selenium deficiency has not been recorded was found to be 45..mu..g. of Se/kg. body weight when sodium selenite was administered as a single intramuscular injection. Marked pulmonary congestion and oedema were constantly present with degenerative changes in liver and kidney. A similarity was noted between the autopsy findings of acute selenosis and those described for enterotoxaemia. 13 references, 4 figures.

  2. Comparative study of selenite adsorption on carbon based adsorbents and activated alumina.

    Science.gov (United States)

    Jegadeesan, G; Mondal, K; Lalvani, S B

    2003-08-01

    The sorption characteristics of carbon-based adsorbents such as activated carbon and chitin for the removal of selenite, Se (IV), an anionic, hazardous contaminant, are compared with those of alpha and gamma alumina. Batch experiments were conducted to determine the influence of pH, concentration of adsorbate, adsorbent loading and temperature on the sorption characteristics of the adsorbents. Generally, low pH of the solution resulted in favorable selenium removal. With the exception of activated carbon, uptakes decreased with increase in temperature. In comparison, chitin was found to be far less effective for the removal of Se (IV) from aqueous solutions. The data also showed that gamma alumina provided higher selenium removal percentages (99%) compared to alpha alumina (94%), activated carbon (87%) and chitin (49%). The selenite removal was found to decrease with increasing initial Se (IV) concentration in the solution. Adsorption capacities of the adsorbents are reported in terms of their Langmuir adsorption isotherms. The adsorption capacity (on unit mass basis) of the adsorbents for selenite is in the order: chitin (specific area (sa) = 9.58 m2 g(-1)) activated carbon (sa = 96.37 m2 g(-1)) < alpha alumina (sa = 6 m2 g(-1)) < gamma alumina (sa = 150 m2 g(-1)).

  3. Distribution and metabolism of selenite and selenomethionine in the Japanese quail.

    Science.gov (United States)

    Anan, Yasumi; Ohbo, Ai; Tani, Yuta; Hatakeyama, Yoshiko; Yawata, Ayako; Ogra, Yasumitsu

    2012-05-01

    Compared to the many studies on the physiological and toxicological effects of selenium (Se) in mammals, avian Se metabolism is still an unexplored topic. Some birds are useful as poultry for human nutrition. Moreover, birds belong to higher trophic levels in the biosphere and thus may play an important role in Se circulation in the ecosystem in the same way as mammals do. In this study, we analyzed the distribution and metabolism of Se in an experimental bird, the Japanese quail, which was fed drinking water containing sodium selenite or selenomethionine (SeMet). The highest concentration of Se was detected in the pancreas, followed by down feathers, liver, and kidneys. SeMet was more efficiently incorporated into the quail than selenite. The specific and preferable distribution of Se to the high molecular weight fraction in the serum of the quail was observed only in the SeMet-ingestion group. As in mammals, selenosugar and trimethylselenonium were the major metabolites in quail excreta. Three unknown Se metabolites were detected by HPLC-ICP-MS. Although part of the metabolic pathway of Se in the Japanese quail fed selenite and SeMet was the same as that observed in mammals, the bird also showed certain avian-specific metabolic process for Se.

  4. Analysis of the improvement of selenite retention in smectite by adding alumina nanoparticles.

    Science.gov (United States)

    Mayordomo, Natalia; Alonso, Ursula; Missana, Tiziana

    2016-12-01

    Smectite clay is used as barrier for hazardous waste retention and confinement. It is a powerful material to retain cations, but less effective for retaining anionic species like selenite. This study shows that the addition of a small percentage of γ-Al 2 O 3 nanoparticles to smectite significantly improves selenite sorption. γ-Al 2 O 3 nanoparticles provide high surface area and positively charged surface sites within a wide range of pH, since their point of zero charge is at pH8-9. An addition of 20wt% of γ-Al 2 O 3 to smectite is sufficient to approach the sorption capacity of pure alumina. To analyze the sorption behavior of the smectite/oxide mixtures, a nonelectrostatic surface complexation model was considered, accounting for the surface complexation of HSeO 3 - and SeO 3 2- , the anion competition, and the formation of surface ternary complexes with major cations present in the solution. Selenite sorption in mixtures was satisfactorily described with the surface parameters and complexation constants defined for the pure systems, accounting only for the mixture weight fractions. Sorption in mixtures was additive despite the particle heteroaggregation observed in previous stability studies carried out on smectite/γ-Al 2 O 3 mixtures. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Selenium homeostasis and induction of thioredoxin reductase during long term selenite supplementation in the rat

    DEFF Research Database (Denmark)

    Erkhembayar, Suvd; Mollbrink, Annelie; Eriksson, Malin

    2011-01-01

    -dependent increase in blood and liver selenium levels, with plateaus at 6 and 8weeks, respectively. These plateaus were reached at the same level of selenium regardless of dose, and no further accumulation was observed. A selenium-dependent increase in the activity of TrxR1 in parallel with the increase in liver...... selenium levels was also seen, and the induction of TrxR1 mRNA was seen only during the first three days of treatment, when the levels of selenium in the liver were increasing. Sodium selenite at 1 and 5μg/mL did not affect body weight or relative liver mass. We concluded that long-term treatment...... with selenite did not cause accumulation of selenium and that the activity of TrxR1 in the liver rose with the selenium levels. We therefore suggest that sodium selenite at doses up to 5μg/mL could be used for long-term tumour prevention....

  6. Effect of hesperetin on chaperone activity in selenite-induced cataract

    Directory of Open Access Journals (Sweden)

    Nakazawa Yosuke

    2016-01-01

    Full Text Available Background. Chaperone activity of α-crystallin in the lens works to prevent protein aggregation and is important to maintain the lens transparency. This study evaluated the effect of hesperetin on lens chaperone activity in selenite-induced cataracts. Methodology. Thirteen-day-old rats were divided into four groups. Animals were given hesperetin (groups G2 and G4 or vehicle (G1 and G3 on Days 0, 1, and 2. Rats in G3 and G4 were administered selenite subcutaneously 4 hours after the first hesperetin injection. On Days 2, 4, and 6, cataract grades were evaluated using slit-lamp biomicroscopy. The amount of a-crystallin and chaperone activity in water-soluble fraction were measured after animals sacrificed. Results. G3 on day 4 had developed significant cataract, as an average cataract grading of 4.6 ± 0.2. In contrast, G4 had less severe central opacities and lower stage cataracts than G3, as an average cataract grading of 2.4 ± 0.4. The a-crystallin levels in G3 lenses were lower than in G1, but the same as G4. Additionally, chaperone activity was weaker in G3 lenses than G1, but the same as in G4. Conclusions. Our results suggest that hesperetin can prevent the decreasing lens chaperone activity and a-crystallin water solubility by administered of selenite.

  7. Sorption mechanisms of selenium species (selenite and selenate) on copper-based minerals

    International Nuclear Information System (INIS)

    Devoy, J.

    2001-09-01

    The sorption of radionuclides on the surface of minerals represents a process capable to delay the migration of the elements from a spent fuel deep repository towards the biosphere. In the framework of a deep underground repository, an engineered clay barrier has a high trapping capacity for cationic radio-elements, in particular because of the negative charge of clay surfaces. However, anionic radioelements like selenium species, would be only weakly retained by chemical processes. In order to optimize the trapping capacity of a clay barrier with respect to anionic species, prospective studies are carried out in order to find and evaluate some minerals with specific chemical trapping functions. Among radionuclides, the case of selenium has to be considered because its isotope 79 Se is present in radioactive wastes and has a half life time of 6.5 10 4 years. It is also judicious to find a mineral capable of trapping simultaneously several anionic radio-elements. Copper oxides and sulfides (Cu 2 O, CuO, Cu 2 S, CuS, CuFeS 2 and Cu 5 FeS 4 ) are good adsorbents with respect to selenium species (selenite and selenate). These minerals, with their selenium retention properties, could be used also for the decontamination of soils and waters or to process industrial effluents. The sorption mechanisms have been studied in details for copper oxides (Cu 2 O and CuO) with respect to selenite and selenate. Chalcomenite precipitates in acid pH conditions when selenite is added to a Cu 2 O and CuO suspension. Selenate, in contact with cuprite (Cu 2 O) leads also to a selenium-based precipitate in acid pH environment. For higher pH values, selenite and selenate are adsorbed on copper oxides (Cu 2 O and CuO) and lead to internal and external sphere complexes, respectively. In the case of a selenite/cuprite mixture in basic pH environment and at the equilibrium, a chemical reaction occurs between the oxidation product of cuprite, Cu(OH) 2 and HSeO 3 . A preliminary study of

  8. Timescales of Coherent Dynamics in the Light Harvesting Complex 2 (LH2) of Rhodobacter sphaeroides.

    Science.gov (United States)

    Fidler, Andrew F; Singh, Ved P; Long, Phillip D; Dahlberg, Peter D; Engel, Gregory S

    2013-05-02

    The initial dynamics of energy transfer in the light harvesting complex 2 from Rhodobacter sphaeroides were investigated with polarization controlled two-dimensional spectroscopy. This method allows only the coherent electronic motions to be observed revealing the timescale of dephasing among the excited states. We observe persistent coherence among all states and assign ensemble dephasing rates for the various coherences. A simple model is utilized to connect the spectroscopic transitions to the molecular structure, allowing us to distinguish coherences between the two rings of chromophores and coherences within the rings. We also compare dephasing rates between excited states to dephasing rates between the ground and excited states, revealing that the coherences between excited states dephase on a slower timescale than coherences between the ground and excited states.

  9. In vitro assembly of a prohead-like structure of the Rhodobacter capsulatus gene transfer agent

    International Nuclear Information System (INIS)

    Spano, Anthony J.; Chen, Frank S.; Goodman, Benjamin E.; Sabat, Agnes E.; Simon, Martha N.; Wall, Joseph S.; Correia, John J.; McIvor, Wilson; Newcomb, William W.; Brown, Jay C.; Schnur, Joel M.; Lebedev, Nikolai

    2007-01-01

    The gene transfer agent (GTA) is a phage-like particle capable of exchanging double-stranded DNA fragments between cells of the photosynthetic bacterium Rhodobacter capsulatus. Here we show that the major capsid protein of GTA, expressed in E. coli, can be assembled into prohead-like structures in the presence of calcium ions in vitro. Transmission electron microscopy (TEM) of uranyl acetate staining material and thin sections of glutaraldehyde-fixed material demonstrates that these associates have spherical structures with diameters in the range of 27-35 nm. The analysis of scanning TEM images revealed particles of mass ∼ 4.3 MDa, representing 101 ± 11 copies of the monomeric subunit. The establishment of this simple and rapid method to form prohead-like particles permits the GTA system to be used for genome manipulation within the photosynthetic bacterium, for specific targeted drug delivery, and for the construction of biologically based distributed autonomous sensors for environmental monitoring

  10. Improved hydrogen production by uptake hydrogenase deficient mutant strain of Rhodobacter sphaeroides O.U.001

    Energy Technology Data Exchange (ETDEWEB)

    Kars, Goekhan; Guenduez, Ufuk; Yuecel, Meral [Department of Biological Sciences, Middle East Technical University, 06531 Ankara (Turkey); Rakhely, Gabor; Kovacs, Kornel L. [Institute of Biophysics, Biological Research Centre, Hungarian Academy of Sciences, Szeged (Hungary); Eroglu, Inci [Department of Chemical Engineering, Middle East Technical University, 06531 Ankara (Turkey)

    2008-06-15

    Rhodobacter sphaeroides O.U.001 is a purple non-sulfur bacterium producing hydrogen under photoheterotrophic conditions. Hydrogen is produced by Mo-nitrogenase enzyme and substantial amount of H{sub 2} is reoxidized by a membrane-bound uptake hydrogenase in the wild type strain. To improve the hydrogen producing capacity of the cells, a suicide vector containing a gentamicin cassette in the hupSL genes was introduced into R. sphaeroiodes O.U.001 and the uptake hydrogenase genes were destroyed by site directed mutagenesis. The correct integration of the construct was confirmed by uptake hydrogenase activity measurement, PCR and subsequent sequence analysis. The wild type and the mutant cells showed similar growth patterns but the total volume of hydrogen gas evolved by the mutant was 20% higher than that of the wild type strain. This result demonstrated that the hydrogen produced by the nitrogenase was not consumed by uptake hydrogenase leading to higher hydrogen production. (author)

  11. Pharmacokinetics and Toxicity of Sodium Selenite in the Treatment of Patients with Carcinoma in a Phase I Clinical Trial: The SECAR Study

    DEFF Research Database (Denmark)

    Brodin, Ola; Eksborg, Staffan; Wallenberg, Marita

    2015-01-01

    and the MTD of sodium selenite. The secondary endpoint was primary response evaluation. Results and Conclusion: MTD was defined as 10.2 mg/m(2), with a calculated median plasma half-life of 18.25 h. The maximum plasma concentration of selenium from a single dose of selenite increased in a nonlinear pattern...

  12. Effects of 14-day oral low dose selenium nanoparticles and selenite in rat—as determined by metabolite pattern determination

    Directory of Open Access Journals (Sweden)

    Niels Hadrup

    2016-10-01

    Full Text Available Selenium (Se is an essential element with a small difference between physiological and toxic doses. To provide more effective and safe Se dosing regimens, as compared to dosing with ionic selenium, nanoparticle formulations have been developed. However, due to the nano-formulation, unexpected toxic effects may occur. We used metabolite pattern determination in urine to investigate biological and/or toxic effects in rats administered nanoparticles and for comparison included ionic selenium at an equimolar dose in the form of sodium selenite. Low doses of 10 and 100 fold the recommended human high level were employed to study the effects at borderline toxicity. Evaluations of all significantly changed putative metabolites, showed that Se nanoparticles and sodium selenite induced similar dose dependent changes of the metabolite pattern. Putative identified metabolites included increased decenedioic acid and hydroxydecanedioic acid for both Se formulations whereas dipeptides were only increased for selenite. These effects could reflect altered fatty acid and protein metabolism, respectively.

  13. Lifelong consumption of sodium selenite: gender differences on blood-brain barrier permeability in convulsive, hypoglycemic rats.

    Science.gov (United States)

    Seker, F Burcu; Akgul, Sibel; Oztas, Baria

    2008-07-01

    The aim of this study was to compare the effects of hypoglycemia and induced convulsions on the blood-brain barrier permeability in rats with or without lifelong administration of sodium selenite. There is a significant decrease of the blood-brain barrier permeability in three brain regions of convulsive, hypoglycemic male rats treated with sodium selenite when compared to sex-matched untreated rats (p0.05). The blood-brain barrier permeability of the left and right hemispheres of untreated, moderately hypoglycemic convulsive rats of both genders was better than their untreated counterparts (peffect against blood-brain barrier permeability during convulsions and that the effects of sodium selenite are gender-dependent.

  14. Determination of selenite and selenate in human urine by ion chromatography and inductively coupled plasma mass spectrometry

    DEFF Research Database (Denmark)

    Gammelgaard, Bente; Jons, O.

    2000-01-01

    The selenium species selenite, selenate and selenomethionine were separated in aqueous solution by ion chromatography. The separation was performed on an IonPac AG11 in series with an AS11 anion exchange column by elution with 25 mM sodium hydroxide in 2% methanol. The Se-78 and Se-82 isotopes were...... monitored in the inductively coupled plasma mass spectrometry (ICP-MS) detector. When the chromatographic system was applied to analysis of urine samples diluted 1 + 1, the selenomethionine signal appeared in the front together with other unresolved selenium species, while the selenite and selenate signals...... and selenate, respectively, corresponding to absolute amounts of 8 and 16 pg, respectively. Calculations were based on peak height measurements of the Se-82 isotope. In 23 analysed urine samples, the concentration of selenite was in the range selenium...

  15. Envenimation mortelle par morsure de serpent chez une femme ...

    African Journals Online (AJOL)

    Les auteurs rapportent un cas de morsure de serpent au niveau de la face chez une femme enceinte, dont l'évolution a été marquée par l'installation d'un oedème cervico-facial nécessitant une trachéotomie en urgence, et une mort foetale in utero avec troubles de l'hémostase responsable du décès maternel dans un ...

  16. Stress au travail chez les enseignants: approches diagnostique et ...

    African Journals Online (AJOL)

    Position du problème: déterminer la prévalence et identifier les facteurs déterminants du stress professionnel chez les enseignants de l'école primaire publique au Togo. Méthodes: Il s'agit d'une étude transversale menée sur cinq mois, de décembre 2011 à avril 2012, dans la commune de Lomé et la préfecture du Golfe, ...

  17. Prevalence des hemolysines chez les donneurs de sang de groupe ...

    African Journals Online (AJOL)

    Objectifs : Déterminer la fréquence et le titre des hémolysines anti-A et anti-B dans la population des donneurs O et de prédire de l'intérêt de la systématisation de leur recherche chez tous les donneurs O par l'évaluation du risque d'accident transfusionnels liés aux hémolysines. Méthodologie : Etude prospective au ...

  18. Syntheses, structures and characterizations of three novel vanadium selenites with organically bonded copper/nickel complex

    Science.gov (United States)

    Qian, Cheng; Kong, Fang; Mao, Jiang-Gao

    2016-06-01

    A series of vanadium selenites covalently bonded with metal-organic complex, namely, Ni(2,2-bipy)2V2O4(SeO3)2 (1), Cu(2,2-bipy)V2O4(SeO3)2·0.5H2O (2) and Cu2(2,2-bipy)2V5O12(SeO3)2 (3) (2,2-bipy=2,2-bipyridine) have been hydrothermally synthesized and structurally characterized. They exhibit three different structural dimensions, from 0D cluster, 1D chain to 2D layer. Compound 1 features a 0D {Ni(2,2-bipy)2V2O4(SeO3)2}2 dimeric cluster composed of two {Ni(2,2-bipy)2}2+ moieties connected by the {V4O8(SeO3)4}4- cluster. Compound 2 shows a 1D {Cu(2,2-bipy)V2O4(SeO3)2}n chain in which the {Cu2(2,2-bipy)2}4+ moieties are bridged by the {V4O8(SeO3)4}4- clusters. Compound 3 displays a 2D structure consisted of mixed valence vanadium selenites layers {VIVVV4SeIV2O18}n4- and {Cu(2,2-bipy)}2+ complex moieties. The adjacent layers are further interconnected via π-π interactions between the 2,2-bipy ligands exhibiting an interesting 3D supramolecular architecture. Both compound 1 and 2 contain a new {V4O8(SeO3)4}4- cluster and compound 3 exhibits the first 2D vanadate polyhedral layer in vanadium selenites/tellurites with organic moieties.

  19. Selenite and tellurite form mixed seleno- and tellurotrisulfides with CstR from Staphylococcus aureus.

    Science.gov (United States)

    Luebke, Justin L; Arnold, Randy J; Giedroc, David P

    2013-04-01

    Staphylococcus aureus CstR (CsoR-like sulfur transferase repressor) is a member of the CsoR family of transition metal sensing metalloregulatory proteins. Unlike CsoR, CstR does not form a stable complex with transition metals but instead reacts with sulfite to form a mixture of di- and trisulfide species, CstR2(RS-SR') and CstR2(RS-S-SR')n)n=1 or 2, respectively. Here, we investigate if CstR performs similar chemistry with related chalcogen oxyanions selenite and tellurite. In this work we show by high resolution tandem mass spectrometry that CstR is readily modified by selenite (SeO3(2-)) or tellurite (TeO3(2-)) to form a mixture of intersubunit disulfides and selenotrisulfides or tellurotrisulfides, respectively, between Cys31 and Cys60'. Analogous studies with S. aureus CsoR reveals no reaction with selenite and minimal reaction with tellurite. All cross-linked forms of CstR exhibit reduced DNA binding affinity. We show that Cys31 initiates the reaction with sulfite through the formation of S-sulfocysteine (RS-SO3(2-)) and Cys60 is required to fully derivatize CstR to CstR2(RS-SR') and CstR2(RS-S-SR'). The modification of Cys31 also drives an allosteric switch that negatively regulates DNA binding while derivatization of Cys60 alone has no effect on DNA binding. These results highlight the differences between CstRs and CsoRs in chemical reactivity and metal ion selectivity and establish Cys31 as the functionally important cysteine residue in CstRs.

  20. Sorption and reduction of selenite on chlorite surfaces in the presence of Fe(II) ions.

    Science.gov (United States)

    Baik, Min Hoon; Lee, Seung Yeop; Jeong, Jongtae

    2013-12-01

    The sorption and reduction of selenite on chlorite surfaces in the presence of Fe(II) ions were investigated as a function of pH, Se(IV) concentration, and Fe(II) concentration under an anoxic condition. The sorption of Se(IV) onto chlorite surfaces followed the Langmuir isotherm regardless of the presence of Fe(II) ions in the solution. The Se(IV) sorption was observed to be very low at all pH values when the solution was Fe(II)-free or the concentration of Fe(II) ions was as low as 0.5 mg/L. However, the Se(IV) sorption was enhanced at a pH > 6.5 when the Fe(II) concentration was higher than 5 mg/L because of the increased sorption of Fe(II) onto the chlorite surfaces. XANES (X-ray absorption near edge structure) spectra of the Se K-edge showed that most of the sorbed Se(IV) was reduced to Se(0) by Fe(II) sorbed onto the chlorite surfaces, especially at pH > 9. The combined results of field-emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) also showed that elemental selenium and goethite were formed and precipitated on the chlorite surfaces during the sorption of selenite. Consequently it can be concluded that Se(IV) can be reduced to Se(0) in the presence of Fe(II) ions by the surface catalytic oxidation of Fe(II) into Fe(III) and the formation of goethite at neutral and particularly alkaline conditions. Thus the mobility of selenite in groundwater is expected to be reduced by the presence of a relatively higher concentration of Fe(II) in subsurface environments. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Structural and Phylogenetic Analysis of Rhodobacter capsulatus NifF: Uncovering General Features of Nitrogen-fixation (nif-Flavodoxins

    Directory of Open Access Journals (Sweden)

    Inmaculada Pérez-Dorado

    2013-01-01

    Full Text Available Analysis of the crystal structure of NifF from Rhodobacter capsulatus and its homologues reported so far reflects the existence of unique structural features in nif flavodoxins: a leucine at the re face of the isoalloxazine, an eight-residue insertion at the C-terminus of the 50’s loop and a remarkable difference in the electrostatic potential surface with respect to non-nif flavodoxins. A phylogenetic study on 64 sequences from 52 bacterial species revealed four clusters, including different functional prototypes, correlating the previously defined as “short-chain” with the firmicutes flavodoxins and the “long-chain” with gram-negative species. The comparison of Rhodobacter NifF structure with other bacterial flavodoxin prototypes discloses the concurrence of specific features of these functional electron donors to nitrogenase.

  2. Structural and phylogenetic analysis of Rhodobacter capsulatus NifF: uncovering general features of nitrogen-fixation (nif)-flavodoxins.

    Science.gov (United States)

    Pérez-Dorado, Inmaculada; Bortolotti, Ana; Cortez, Néstor; Hermoso, Juan A

    2013-01-09

    Analysis of the crystal structure of NifF from Rhodobacter capsulatus and its homologues reported so far reflects the existence of unique structural features in nif flavodoxins: a leucine at the re face of the isoalloxazine, an eight-residue insertion at the C-terminus of the 50's loop and a remarkable difference in the electrostatic potential surface with respect to non-nif flavodoxins. A phylogenetic study on 64 sequences from 52 bacterial species revealed four clusters, including different functional prototypes, correlating the previously defined as "short-chain" with the firmicutes flavodoxins and the "long-chain" with gram-negative species. The comparison of Rhodobacter NifF structure with other bacterial flavodoxin prototypes discloses the concurrence of specific features of these functional electron donors to nitrogenase.

  3. Selenite and tellurite form mixed seleno- and tellurotrisulfides with CstR from Staphylococcus aureus

    OpenAIRE

    Luebke, Justin L.; Arnold, Randy J.; Giedroc, David P.

    2013-01-01

    Staphylococcus aureus CstR (CsoR-like sulfur transferase repressor) is a member of the CsoR family of transition metal sensing metalloregulatory proteins. Unlike CsoR, CstR does not form a stable complex with transition metals but instead reacts with sulfite to form a mixture of di- and trisulfide species, CstR2(RS-SR′) and CstR2(RS-S-SR′)n, n = 1 or 2, respectively. Here, we investigate if CstR performs similar chemistry with related chalcogen oxyanions selenite and tellurite. In this work w...

  4. Influence of selenite and selenate supplementation on the chromium uptake and translocation in Allium cepa

    International Nuclear Information System (INIS)

    Karuna Shanker; Setia, Seema; Srivastava, Shalini; Dass, Sahab; Srivastava, Rohit; Satya Prakash; Srivastava, M.M.

    1997-01-01

    Pot experiments were conducted on onion plant to study the effects of selenite and selenate treatments (0.5-6.0) μg ml -1 on the uptake and translocation of root absorbed chromium irrigated with 2 and 5 μg ml -1 of chromium in sand and soil. Both the form of selenium (SeO 3 2- , and SeO 4 2- ) were found equally effective in reducing the chromium burden of the plant. No significant difference (p>0.05) in dry matter yields among various selenium treatments exist suggesting no salt injury occurred in the plants under prevailing conditions. (author). 10 refs., 1 tab

  5. Open reading frame 176 in the photosynthesis gene cluster of Rhodobacter capsulatus encodes idi, a gene for isopentenyl diphosphate isomerase.

    OpenAIRE

    Hahn, F M; Baker, J A; Poulter, C D

    1996-01-01

    Isopentenyl diphosphate (IPP) isomerase catalyzes an essential activation step in the isoprenoid biosynthetic pathway. A database search based on probes from the highly conserved regions in three eukaryotic IPP isomerases revealed substantial similarity with ORF176 in the photosynthesis gene cluster in Rhodobacter capsulatus. The open reading frame was cloned into an Escherichia coli expression vector. The encoded 20-kDa protein, which was purified in two steps by ion exchange and hydrophobic...

  6. Structure of the dimeric PufX-containing core complex of Rhodobacter blasticus by in situ atomic force microscopy.

    Science.gov (United States)

    Scheuring, Simon; Busselez, Johan; Lévy, Daniel

    2005-01-14

    We have studied photosynthetic membranes of wild type Rhodobacter blasticus, a closely related strain to the well studied Rhodobacter sphaeroides, using atomic force microscopy. High-resolution atomic force microscopy topographs of both cytoplasmic and periplasmic surfaces of LH2 and RC-LH1-PufX (RC, reaction center) complexes were acquired in situ. The LH2 is a nonameric ring inserted into the membrane with the 9-fold axis perpendicular to the plane. The core complex is an S-shaped dimer composed of two RCs, each encircled by 13 LH1 alpha/beta-heterodimers, and two PufXs. The LH1 assembly is an open ellipse with a topography-free gap of approximately 25 A. The two PufXs, one of each core, are located at the dimer center. Based on our data, we propose a model of the core complex, which provides explanation for the PufX-induced dimerization of the Rhodobacter core complex. The QB site is located facing a approximately 25-A wide gap within LH1, explaining the PufX-favored quinone passage in and out of the core complex.

  7. Selenium intoxication with selenite broth resulting in acute renal failure and severe gastritis

    Directory of Open Access Journals (Sweden)

    Kamble P

    2009-01-01

    Full Text Available Selenium (Se is an essential trace element in human and animal nutrition. It is also widely utilized in industrial processes. Reports of acute selenium toxicity in humans are rare. We report a case of a 23-year-old female who consumed about 100 mL of liquid selenite broth and presented with severe nausea, vomiting, abdominal pain, hematemesis and acute renal failure (ARF. The serum selenium level was significantly increased. Gastro-duodenoscopy revealed severe corrosive gastritis. Renal biopsy showed features of acute tubular necrosis (ATN, affecting primarily the proximal tubules. The patient was managed with gastric lavage, blood transfusions, infusion of fresh frozen plasma (FFP and platelet concentrates and hemo-dialysis. The patient was discharged five weeks after admission and her renal functions reco-vered completely by eight weeks after admission. She continues to be on regular follow-up for any possible sequelae of mucosal corrosive damage. This case highlights a case of selenium intoxication from selenite broth resulting in ARF and corrosive gastritis. The recovery was complete.

  8. Separation of Selenite from Inorganic Selenium Ions using TiO{sub 2} Magnetic Nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jongmin; Lim, H. B. [Donkook Univ., Yongin (Korea, Republic of)

    2013-11-15

    A simple and quick separation technique for selenite in natural water was developed using TiO{sub 2} SiO{sub 2}/Fe{sub 3}O{sub 4} nanoparticles. For the synthesis of nanoparticles, a polymer-assisted sol-gel method using hydroxypropyl cellulose (HPC) was developed to control particle dispersion in the synthetic procedure. In addition, titanium butoxide (TBT) precursor, instead of the typical titanium tetra isopropoxide, was used for the formation of the TiO{sub 2} shell. The synthesized nanoparticles were used to separate selenite (Se{sup 4+}) in the presence of Se{sup 6+} or selenium anions for the photocatalytic reduction to Se{sup 0} atom on the TiO{sub 2} shell, followed by magnetic separation using Fe{sub 3}O{sub 4} nanoparticles. The reduction efficiency of the photocatalytic reaction was 81.4% at a UV power of 6W for 3 h with a dark adsorption of 17.5% to the nanoparticles, as determined by inductively coupled plasma-mass spectrometry (ICP-MS). The developed separation method can be used for the speciation and preconcentration of selenium cations in environmental and biological analysis.

  9. Nanocrystalline hydroxyapatite enriched in selenite and manganese ions: physicochemical and antibacterial properties

    Science.gov (United States)

    Kolmas, Joanna; Groszyk, Ewa; Piotrowska, Urszula

    2015-07-01

    In this work, we used the co-precipitation method to synthesize hydroxyapatite (Mn-SeO3-HA) containing both selenium IV (approximately 3.60 wt.%) and manganese II (approximately 0.29 wt.%). Pure hydroxyapatite (HA), hydroxyapatite-containing manganese (II) ions (Mn-HA), and hydroxyapatite-containing selenite ions alone (SeO3-HA), prepared with the same method, were used as reference materials. The structures and physicochemical properties of all the obtained samples were investigated. PXRD studies showed that the obtained materials were homogeneous and consisted of apatite phase. Introducing selenites into the hydroxyapatite crystals considerably affects the size and degree of ordering. Experiments with transmission electron microscopy (TEM) showed that Mn-SeO3-HA crystals are very small, needle-like, and tend to form agglomerates. Fourier transform infrared spectroscopy (FT-IR) and solid-state nuclear magnetic resonance (ssNMR) were used to analyze the structure of the obtained material. Preliminary microbiological tests showed that the material demonstrated antibacterial activity against Staphylococcus aureus, yet such properties were not confirmed regarding Escherichia coli. PACS codes: 61, 76, 81

  10. Molecular structure, vibrational, HOMO-LUMO, MEP and NBO analysis of hafnium selenite

    Science.gov (United States)

    Yankova, Rumyana; Genieva, Svetlana; Dimitrova, Ginka

    2017-08-01

    In hydrothermal condition hafnium selenite with estimated chemical composition Hf(SeO3)2·n(H2O) was obtained and characterized by powder X-Ray diffraction, IR spectroscopy and thermogravimetrical analysis. The composition of the obtained crystalline phase was established as dihydrate of tetraaqua complex of the hafnium selenite [Hf(SeO3)2(H2O)4]·2H2O. The results of the thermogravimetrical analysis are shown that the two hydrated water molecules are released in the temperature interval 80-110°C, while the four coordinated water molecules - at 210-300°C. By DFT method, with Becke's three parameter exchange-functional combined with gradient-corrected correlation functional of Lee, Yang and Parr and 6-31G(d), 6-311 + G(d,p) basis sets and LANL2DZ for Hf atom were calculated the molecular structure, vibrational frequencies and thermodynamic properties of the structure. The UV-Vis spectra and electronic properties are presented. The energy and oscillator strength calculated by time-dependent density functional theory corresponds well with the experimental ones. Molecular electrostatic potential (MEP) was performed. Mulliken population analysis on atomic charges was also calculated. The stability and intramolecular interactions are interpreted by NBO analysis.

  11. Nephrotoxic effects of lead nitrate exposure in diabetic and nondiabetic rats: Involvement of oxidative stress and the protective role of sodium selenite.

    Science.gov (United States)

    Baş, Hatice; Kalender, Yusuf

    2016-10-01

    Heavy metals are known to be toxic to organisms. The present study was undertaken to evaluate the protective effect of sodium selenite against lead nitrate (LN)-induced nephrotoxicity in diabetic and nondiabetic rats. Animals were divided into eight groups where the first was served as a control, whereas the remaining groups were treated with sodium selenite (1 mg/kg b.w.), LN (22.5 mg/kg b.w.) and a combination of LN and sodium selenite and diabetic forms of these groups. Changes in antioxidant enzyme activities, malondialdehide levels, serum urea, uric acid, creatinine levels, body, and kidney weights and histopathological changes were determined after 28 days. LN caused severe histopathological changes, increment in urea, uric acid, creatinine, and MDA levels, also decreasing in antioxidant enzyme activities, body, and kidney weights. In sodium selenite + LN group, we observed the protective effect of sodium selenite on examining parameters. Also diabetes caused alterations on these parameters compared with nondiabetic animals. We found that sodium selenite did not show protective effect on diabetes caused damages. As a result, LN caused nephrotoxicity and sodium selenite alleviated this toxicity but sodium selenite did not protect kidneys against diabetes mediated toxicity. Also, LN caused more harmfull effects in diabetic groups compared with nondiabetic groups. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1229-1240, 2016. © 2015 Wiley Periodicals, Inc.

  12. Selenite and ebselen supplementation attenuates D-galactose-induced oxidative stress and increases expression of SELR and SEP15 in rat lens.

    Science.gov (United States)

    Dai, Jie; Zhou, Jun; Liu, Hongmei; Huang, Kaixun

    2016-12-01

    Selenite and ebselen supplementation has been shown to possess anti-cataract potential in some experimental animal models of cataract, however, the underlying mechanisms remain unclear. The present study was designed to evaluate the anti-cataract effects and the underlying mechanisms of selenite and ebselen supplementation on galactose induced cataract in rats, a common animal model of sugar cataract. Transmission electron microscopy images of lens fiber cells (LFC) and lens epithelial cells (LEC) were observed in D-galactose-induced experimental cataractous rats treated with or without selenite and ebselen, also redox homeostasis and expression of proteins such as selenoprotein R (SELR), 15kD selenoprotein (SEP15), superoxide dismutase 1 (SOD1), catalase (CAT), β-crystallin protein, aldose reductase (AR) and glucose-regulated protein 78 (GRP78) were estimated in the lenses. The results showed that D-galactose injection injured rat lens and resulted in cataract formation; however, selenite and ebselen supplementation markedly alleviated ultrastructural injury of LFC and LEC. Moreover, selenite and ebselen supplementation could mitigate the oxidative damage in rat lens and increase the protein expressions of SELR, SEP15, SOD1, CAT and β-crystallin, as well as decrease the protein expressions of AR and GRP78. Taken together, these findings for the first time reveal the anti-cataract potential of selenite and ebselen in galactosemic cataract, and provide important new insights into the anti-cataract mechanisms of selenite and ebselen in sugar cataract.

  13. Calcifications valvulaires chez l'hémodialysé au Maroc | Faqih | Pan ...

    African Journals Online (AJOL)

    Calcifications valvulaires chez l'hémodialysé au Maroc. Samia Ait Faqih, Béfa Noto-Kadou-Kaza, Lalla Meryam Abouamrane, Naoufal Mtiou, Selma El Khaya, Mohamed Zamd, Ghislaine Medkouri, Mohamed Gharbi Bengahanem, Benyounes Ramdani ...

  14. Maintien de l'abstinence chez les patients alcoolo-dependants ...

    African Journals Online (AJOL)

    Maintien de l'abstinence chez les patients alcoolo-dependants: étude comparee de la disponibilite et du cout du traitement par le baclofene, l'acamprosate, et la naltrexone a Cotonou (Benin) et a Lome (Togo)

  15. Absorption, distribution, metabolism and excretion of selenium following oral administration of elemental selenium nanoparticles or selenite in rats

    DEFF Research Database (Denmark)

    Löschner, Katrin; Hadrup, Niels; Hansen, Marianne

    2014-01-01

    A suspension of nanoparticles of BSA-stabilized red amorphous elemental selenium (Se) or an aqueous solution of sodium selenite was repeatedly administered by oral gavage for 28 days at 0.05 mg/kg bw/day (low dose) or at 0.5 mg/kg bw/day (high dose) as Se to female rats. Prior to administration...

  16. Selenium balance in the adult cat in relation to intake of dietary sodium selenite and organically bound selenium

    NARCIS (Netherlands)

    Todd, S.E.; Thomas, D.G.; Hendriks, W.H.

    2012-01-01

    The response of cats to dietary sodium selenite (Na2SeO3) and organically bound selenium was studied in two separate studies with four cats per treatment and three levels of selenium supplementation (targets 1.0, 1.5 and 2.0 µg/g DM) for each Se source. Whole blood and plasma selenium concentrations

  17. Altered selenium status in Huntington's disease: neuroprotection by selenite in the N171-82Q mouse model.

    Science.gov (United States)

    Lu, Zhen; Marks, Eileen; Chen, Jianfang; Moline, Jenna; Barrows, Lorraine; Raisbeck, Merl; Volitakis, Irene; Cherny, Robert A; Chopra, Vanita; Bush, Ashley I; Hersch, Steven; Fox, Jonathan H

    2014-11-01

    Disruption of redox homeostasis is a prominent feature in the pathogenesis of Huntington's disease (HD). Selenium an essential element nutrient that modulates redox pathways and has been reported to provide protection against both acute neurotoxicity (e.g. methamphetamine) and chronic neurodegeneration (e.g. tauopathy) in mice. The objective of our study was to investigate the effect of sodium selenite, an inorganic form of selenium, on behavioral, brain degeneration and biochemical outcomes in the N171-82Q Huntington's disease mouse model. HD mice, which were supplemented with sodium selenite from 6 to 14 weeks of age, demonstrated increased motor endurance, decreased loss of brain weight, decreased mutant huntingtin aggregate burden and decreased brain oxidized glutathione levels. Biochemical studies revealed that selenite treatment reverted HD-associated changes in liver selenium and plasma glutathione in N171-82Q mice and had effects on brain selenoprotein transcript expression. Further, we found decreased brain selenium content in human autopsy brain. Taken together, we demonstrate a decreased selenium phenotype in human and mouse HD and additionally show some protective effects of selenite in N171-82Q HD mice. Modification of selenium metabolism results in beneficial effects in mouse HD and thus may represent a therapeutic strategy. Copyright © 2014 Elsevier Inc. All rights reserved.

  18. Relationship of membrane-bound sulfhydryl groups to vitamin D-stimulated uptake of [75Se]Selenite by the brush border membrane vesicles from chick duodenum

    International Nuclear Information System (INIS)

    Mykkanen, H.M.; Wasserman, R.H.

    1990-01-01

    The uptake of selenite by purified brush border membrane vesicles isolated from duodena of rachitic or vitamin D-treated chicks was studied by using radioactive selenite and a rapid filtration technique. Cholecalciferol treatment (500 IU at 72 h) significantly enhanced selenite uptake, a response that decreased when the vesicles were stored at room temperature for 2.5 h prior to the uptake measurement. Preincubation of the vesicles in 1.0 mmol/L H2O2 reduced [75Se]selenite uptake, indicating the involvement of oxidizable groups in the uptake reaction. Iodoacetic acid (IAA), a sulfhydryl-blocking reagent, at 1-2 mmol/L concentration eliminated the difference in selenite uptake due to cholecalciferol and had no effect on vesicles from rachitic animals. A higher concentration of IAA (10 mmol/L) enhanced selenite uptake manyfold and increased the absolute difference due to cholecalciferol treatment. Single intravenous doses of 100 IU cholecalciferol, 100 IU ergocalciferol, or 0.1 micrograms 1,25-dihydroxycholecalciferol also stimulated selenite uptake, suggesting a general response to vitamin D compounds. Normal animals given a single dose of 1,25-dihydroxycholecalciferol 12 h prior to killing also responded. Treatments that enhanced the uptake of [75Se]selenite also increased the amount of membrane-bound sulfhydryl groups, suggesting the involvement of membrane-bound sulfhydryl groups in the vitamin D response. A significant increase in selenite uptake by intravenous 1,25-dihydroxycholecalciferol occurred within 10 min. This rapid effect provides a new tool to probe early biochemical effects of vitamin D on intestinal epithelium

  19. Selenite Treatment Inhibits LAPC-4 Tumor Growth and Prostate-Specific Antigen Secretion in a Xenograft Model of Human Prostate Cancer

    International Nuclear Information System (INIS)

    Bhattacharyya, Rumi S.; Husbeck, Bryan; Feldman, David; Knox, Susan J.

    2008-01-01

    Purpose: Selenium compounds have known chemopreventive effects on prostate cancer. However selenite, an inorganic form of selenium, has not been extensively studied as a treatment option for prostate cancer. Our previous studies have demonstrated the inhibition of androgen receptor expression and androgen stimulated prostate-specific antigen (PSA) expression by selenite in human prostate cancer cell lines. In this study, we investigated the in vivo effects of selenite as a therapy to treat mice with established LAPC-4 tumors. Methods and Materials: Male mice harboring androgen-dependent LAPC-4 xenograft tumors were treated with selenite (2 mg/kg intraperitoneally three times per week) or vehicle for 42 days. In addition, androgen-independent LAPC-4 xenograft tumors were generated in female mice over 4 to 6 months. Once established, androgen-independent LAPC-4 tumor fragments were passaged into female mice and were treated with selenite or vehicle for 42 days. Changes in tumor volume and serum PSA levels were assessed. Results: Selenite significantly decreased androgen-dependent LAPC-4 tumor growth in male mice over 42 days (p < 0.001). Relative tumor volume was decreased by 41% in selenite-treated animals compared with vehicle-treated animals. The inhibition of LAPC-4 tumor growth corresponded to a marked decrease in serum PSA levels (p < 0.01). In the androgen-independent LAPC-4 tumors in female mice, selenite treatment decreased tumor volume by 58% after 42 days of treatment (p < 0.001). Conclusions: These results suggest that selenite may have potential as a novel therapeutic agent to treat both androgen-dependent and androgen-independent prostate cancer

  20. Study of the Cupriavidus metallidurans CH34 resistance of selenite and selenate oxy-anions: accumulation, localisation and transformation of selenium

    International Nuclear Information System (INIS)

    Avoscan, L.

    2007-06-01

    Selenium is an essential trace element for the living organisms but it is very toxic at high concentration. Selenite and selenate oxides, soluble forms, highly toxic and bio-assimilable, are the most prevalent forms in the environment. Some soil micro-organisms play a dominant role and contribute to the natural cycle of selenium. Our study model, Cupriavidus (formerly Ralstonia) metallidurans CH34, a telluric bacterium characteristic of metal-contaminated biotopes, is known to resist selenite by reducing it into elemental selenium, an insoluble and less toxic form of selenium. In order to better understand the mechanisms of selenium reduction in the bacteria, three methods of speciation were combined (XAS (XANES and EXAFS), HPLC-ICP-MS and SDS-PAGEPIXE). They were completed by the direct quantification of selenium accumulated in the bacteria. Speciation analyses highlighted the existence of two mechanisms of reduction of selenium oxides in C. metallidurans CH34. Assimilation transforms selenite and selenate into organic selenium, identified as seleno-methionine and leads to its non-specific incorporation into bacterial proteins (presence of selenious proteins). Detoxication precipitates selenite in nano-particles of elemental selenium. This way of detoxication is not set up after an exposure to selenate although it is nevertheless possible to detect elemental selenium but in very small amount compared to the exposure of selenite. Seleno-diglutathion is detected in bacteria stressed by an exposure to selenate in medium limited in sulphate. Bacteria exposed to selenite accumulate 25 times more selenium than when they are exposed to selenate. The study of mutants resistant to selenite, which do not express the membrane protein DedA, showed that the accumulation of selenium after exposure to selenite is decreased compared with the wild strain meaning probable link between the transport of selenite and the DedA protein. Finally, selenate would use the sulphate permease

  1. Recherche et Titrage des Hémolysines Anti-A et Anti-B Chez Les ...

    African Journals Online (AJOL)

    Les hémolysines apparaissent suite à une immunisation ABO et peuvent causer, à titre élevé, une hémolyse chez le receveur de sang ou chez le nouveau-né. ... Mots Clés: Hémolysines anti-A et anti-A, Incompatibilité foeto-maternelle ABO, Maladie hémolytique du nouveau-né, Période du post-partum immédiate ...

  2. Caractéristiques épidémiologiques du cancer de la vessie chez la ...

    African Journals Online (AJOL)

    Le tabagisme était retrouvé chez 29,6 % des patientes,l'exposition professionnelle aux carcinogènes dans 5.4 % des cas. Discussion: L'incidence du cancer de la vessie chez la femme est parmi les plus basses dans le monde. Elle est plus élevée dans le grand Tunis et les zones côtières. Elle augmente directement avec ...

  3. Les infections urinaires chez les patients insuffisants rénaux ...

    African Journals Online (AJOL)

    L'infection urinaire chez l'insuffisant rénal est fréquente et particulière dans sa prise en charge diagnostique et thérapeutique. L'objectif de notre étude est de déterminer le profil bactériologique et d'étudier les facteurs de risque des infections urinaires chez le patient insuffisant rénal chronique en milieu de néphrologie.

  4. Effect of sulfide, selenite and mercuric mercury on the growth and methylation capacity of the sulfate reducing bacterium Desulfovibrio desulfuricans

    Energy Technology Data Exchange (ETDEWEB)

    Truong, Hoang-Yen T. [Department of Biology, Laurentian University, Sudbury, Ontario, Canada P3E 2C6 (Canada); Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, Canada P3E 2C6 (Canada); Chen, Yu-Wei [Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, Canada P3E 2C6 (Canada); Belzile, Nelson, E-mail: nbelzile@laurentian.ca [Department of Chemistry and Biochemistry, Laurentian University, Sudbury, Ontario, Canada P3E 2C6 (Canada); Cooperative Freshwater Ecology Unit, Laurentian University, Sudbury, Ontario, Canada P3E 2C6 (Canada)

    2013-04-01

    Cultures of the sulfate reducing bacteria Desulfovibrio desulfuricans were grown under anoxic conditions to study the effect of added sulfide, selenite and mercuric ions. A chemical trap consisting in a CuSO{sub 4} solution was used to control the poisoning effect induced by the bacterial production of hydrogen sulfide via the precipitation of CuS. Following the addition of Hg{sup 2+}, the formation of methylmercury (MeHg) was correlated to bacterial proliferation with most of MeHg found in the culture medium. A large fraction (50–80%) of added Hg{sup 2+} to a culture ended up in a solid phase (Hg{sup 0} and likely HgS) limiting its bioavailability to cells with elemental Hg representing ∼ 40% of the solid. Following the addition of selenite, a small fraction was converted into Se(0) inside the cells and, even though the conversion to this selenium species increased with the increase of added selenite, it never reached more than 49% of the added amount. The formation of volatile dimethylselenide is suggested as another detoxification mechanism. In cultures containing both added selenite and mercuric ions, elemental forms of the two compounds were still produced and the increase of selenium in the residual fraction of the culture suggests the formation of mercuric selenite limiting the bioavailability of both elements to cells. - Highlights: ► Detoxification mechanisms of D. desulfuricans were studied in presence of added sulfide, selenite and mercuric ions. ► The poisoning effect of H{sub 2}S added to or generated by cultures of D. desulfuricans can be controlled with a chemical trap. ► The addition of selenite to cultures triggered the formation of elemental Se and other forms of volatile and non-volatile Se. ► The addition of mercuric ions to cultures led to the production of methylmercury, volatile Hg and solid mercuric sulfide. ► With both Se and Hg added to cultures, fractionation of species in solid and liquid phases suggests the formation of HgSe.

  5. Extracellular thiol-assisted selenium uptake dependent on the x(c)(-) cystine transporter explains the cancer-specific cytotoxicity of selenite

    DEFF Research Database (Denmark)

    Olm, E.; Fernandes, A. P.; Hebert, C.

    2009-01-01

    The selenium salt selenite (SeO32-) is cytotoxic in low to moderate concentrations, with a remarkable specificity for cancer cells resistant to conventional chemotherapy. Our data show that selenium uptake and accumulation, rather than intracellular events, are crucial to the specific selenite...... cytotoxicity observed in resistant cancer cells. We show that selenium uptake depends on extracellular reduction, and that the extracellular environment is a key factor specific to selenite cytotoxicity. The extracellular reduction is mediated by cysteine, and the efficacy is determined by the uptake...

  6. Bases chimiosensorielles du comportement alimentaire chez les poissons

    OpenAIRE

    Saglio, P.

    1981-01-01

    Le comportement alimentaire, indispensable à la survie de l'individu et donc de l'espèce, occupe à ce titre une position de première importance dans la hiérarchie des comportements fondamentaux qui tous en dépendent très étroitement. Chez les poissons, cette prééminence se trouve illustrée par l'extrême diversité des supports sensoriels impliqués et des expressions comportementales qui leur sont liées. A la suite d'un certain nombre de mises en évidence neurophysiologiques et éthologiques de ...

  7. Transient grating spectroscopy in photosynthetic purple bacteria Rhodobacter sphaeroides 2.4.1

    Energy Technology Data Exchange (ETDEWEB)

    Sugisaki, Mitsuru, E-mail: mitsuru@sci.osaka-cu.ac.j [CREST-JST and Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585 (Japan); Fujiwara, Masazumi; Fujii, Ritsuko [CREST-JST and Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585 (Japan); Nakagawa, Katsunori; Nango, Mamoru [CREST-JST and Graduate School of Engineering, Nagoya Institute of Technology, Gokiso, Showa, Nagoya 466-8555 (Japan); Cogdell, Richard J. [Glasgow Biomedical Research Centre, IBLS, University of Glasgow, 126 University Place, Glasgow G12 8TA, Scotland (United Kingdom); Hashimoto, Hideki [CREST-JST and Graduate School of Science, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi, Osaka 558-8585 (Japan)

    2009-12-15

    The vibronic coherence of photosynthetic pigment-protein complexes has been investigated by means of transient grating spectroscopy using sub 20 fs optical pulses. In the present work, we focus our attention on the LH2 antenna complexes from Rhodobacter sphaeroides 2.4.1 because the information about their structure investigated by the electron and atomic force microscopy is available and the electric levels of pigments are well resolved, resulting in clear absorption spectrum. The vibronic coherent oscillations with a period of a few tens of femtoseconds have been clearly observed. We found that the temporal change of the coherent oscillations reflects the vibrational relaxation in the ground state. Calculations based on the Brownian oscillator model were performed under the impulsive excitation limit. The spectral density has been determined from the Raman measurement of spheroidene. Good agreement between the calculation and the experimental results has been achieved in the linear absorption spectrum and transient grating signal, which strongly supports the validity of our model.

  8. Potential use of thermophilic dark fermentation effluents in photofermentative hydrogen production by Rhodobacter capsulatus

    Energy Technology Data Exchange (ETDEWEB)

    Ozgura, E.; Afsar, N.; Eroglu, I. [Middle East Technical University, Department of Chemical Engineering, 06531 Ankara (Turkey); De Vrije, T.; Claassen, P.A.M. [Wageningen UR, Agrotechnology and Food Sciences Group, Wageningen UR, P.O. Box 17, 6700 AA Wageningen (Netherlands); Yucel, M.; Gunduz, U. [Middle East Technical University, Department of Biology, 06531 Ankara (Turkey)

    2010-12-15

    Biological hydrogen production by a sequential operation of dark and photofermentation is a promising route to produce hydrogen. The possibility of using renewable resources, like biomass and agro-industrial wastes, provides a dual effect of sustainability in biohydrogen production and simultaneous waste removal. In this study, photofermentative hydrogen production on effluents of thermophilic dark fermentations on glucose, potato steam peels (PSP) hydrolysate and molasses was investigated in indoor, batch operated bioreactors. An extreme thermophile Caldicellulosiruptor saccharolyticus was used in the dark fermentation step, and Rhodobacter capsulatus (DSM1710) was used in the photofermentation step. Addition of buffer, Fe and Mo to dark fermentor effluents (DFEs) improved the overall efficiency of hydrogen production. The initial acetate concentration in the DFE needed to be adjusted to 30-40 mM by dilution to increase the yield of hydrogen in batch light-supported fermentations. The thermophilic DFEs are suitable for photofermentative hydrogen production, provided that they are supplemented with buffer and nutrients. The overall hydrogen yield of the two-step fermentations was higher than the yield of single step dark fermentations.

  9. Phytoavailability and geospeciation of cadmium in contaminated soil remediated by Rhodobacter sphaeroides.

    Science.gov (United States)

    Fan, Wenhong; Jia, Yingying; Li, Xiaomin; Jiang, Wei; Lu, Lin

    2012-07-01

    A microorganism was isolated from oil field injection water and identified as Rhodobacter sphaeroides. It was used for the remediation of simulated cadmium-contaminated soil. The phytoavailability of Cd was investigated through wheat seedling method to determine the efficiency of remediation. It was found that after remediation, the accumulation of Cd in wheat roots and leaves decreased by 67% and 53%, respectively. The Cd speciation in soil was determined with Tessier extraction procedure. It was found that the total Cd content in soil did not change during the experiments, but the geo-speciation of Cd changed remarkably. Among the five fractions, the concentration of exchangeable phases decreased by 27-46% and that of the phases bound to Fe-Mn oxides increased by 22-44%. The decrease of Cd accumulation in wheat showed significant positive correlation with the decrease of exchangeable phases. It could be concluded that the remediation of R. sphaeroides was carried out through the conversion of Cd to more stable forms. The decrease of sulfate concentration in supernatant indicated that the R. sphaeroides consumed sulfate. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Early bacteriopheophytin reduction in charge separation in reaction centers of Rhodobacter sphaeroides.

    Science.gov (United States)

    Zhu, Jingyi; van Stokkum, Ivo H M; Paparelli, Laura; Jones, Michael R; Groot, Marie Louise

    2013-06-04

    A question at the forefront of biophysical sciences is, to what extent do quantum effects and protein conformational changes play a role in processes such as biological sensing and energy conversion? At the heart of photosynthetic energy transduction lie processes involving ultrafast energy and electron transfers among a small number of tetrapyrrole pigments embedded in the interior of a protein. In the purple bacterial reaction center (RC), a highly efficient ultrafast charge separation takes place between a pair of bacteriochlorophylls: an accessory bacteriochlorophyll (B) and bacteriopheophytin (H). In this work, we applied ultrafast spectroscopy in the visible and near-infrared spectral region to Rhodobacter sphaeroides RCs to accurately track the timing of the electron on BA and HA via the appearance of the BA and HA anion bands. We observed an unexpectedly early rise of the HA⁻ band that challenges the accepted simple picture of stepwise electron transfer with 3 ps and 1 ps time constants. The implications for the mechanism of initial charge separation in bacterial RCs are discussed in terms of a possible adiabatic electron transfer step between BA and HA, and the effect of protein conformation on the electron transfer rate. Copyright © 2013 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  11. A cryptochrome-like protein is involved in the regulation of photosynthesis genes in Rhodobacter sphaeroides.

    Science.gov (United States)

    Hendrischk, Anne-Kathrin; Frühwirth, Sebastian Walter; Moldt, Julia; Pokorny, Richard; Metz, Sebastian; Kaiser, Gebhard; Jäger, Andreas; Batschauer, Alfred; Klug, Gabriele

    2009-11-01

    Blue light receptors belonging to the cryptochrome/photolyase family are found in all kingdoms of life. The functions of photolyases in repair of UV-damaged DNA as well as of cryptochromes in the light-dependent regulation of photomorphogenetic processes and in the circadian clock in plants and animals are well analysed. In prokaryotes, the only role of members of this protein family that could be demonstrated is DNA repair. Recently, we identified a gene for a cryptochrome-like protein (CryB) in the alpha-proteobacterium Rhodobacter sphaeroides. The protein lacks the typical C-terminal extension of cryptochromes, and is not related to the Cry DASH family. Here we demonstrate that CryB binds flavin adenine dinucleotide that can be photoreduced by blue light. CryB binds single-stranded DNA with very high affinity (K(d) approximately 10(-8) M) but double-stranded DNA and single-stranded RNA with far lower affinity (K(d) approximately 10(-6) M). Despite of that, no in vitro repair activity for pyrimidine dimers in single-stranded DNA could be detected. However, we show that CryB clearly affects the expression of genes for pigment-binding proteins and consequently the amount of photosynthetic complexes in R. sphaeroides. Thus, for the first time a role of a bacterial cryptochrome in gene regulation together with a biological function is demonstrated.

  12. Role of the Irr protein in the regulation of iron metabolism in Rhodobacter sphaeroides.

    Directory of Open Access Journals (Sweden)

    Verena Peuser

    Full Text Available In Rhizobia the Irr protein is an important regulator for iron-dependent gene expression. We studied the role of the Irr homolog RSP_3179 in the photosynthetic alpha-proteobacterium Rhodobacter sphaeroides. While Irr had little effect on growth under iron-limiting or non-limiting conditions its deletion resulted in increased resistance to hydrogen peroxide and singlet oxygen. This correlates with an elevated expression of katE for catalase in the Irr mutant compared to the wild type under non-stress conditions. Transcriptome studies revealed that Irr affects the expression of genes for iron metabolism, but also has some influence on genes involved in stress response, citric acid cycle, oxidative phosphorylation, transport, and photosynthesis. Most genes showed higher expression levels in the wild type than in the mutant under normal growth conditions indicating an activator function of Irr. Irr was however not required to activate genes of the iron metabolism in response to iron limitation, which showed even stronger induction in the absence of Irr. This was also true for genes mbfA and ccpA, which were verified as direct targets for Irr. Our results suggest that in R. sphaeroides Irr diminishes the strong induction of genes for iron metabolism under iron starvation.

  13. Improving the hydrogen production capacity of Rhodobacter capsulatus by genetically modifying redox balancing pathways

    Energy Technology Data Exchange (ETDEWEB)

    Oeztuerk, Yavuz [TUEBITAK Research Institute for Genetic Engineering and Biotechnology, Gebze Kocaeli (Turkey); Goekce, Abdulmecit [Istanbul Technical Univ. (Turkey). Dept. of Molecular Biology and Genetics; Guergan, Muazzez; Yuecel, Meral [Middle East Technical Univ., Ankara (Turkey). Dept. of Biology

    2010-07-01

    In Rhodobacter capsulatus, balancing the oxidation-reduction potential (redox-balance) is maintained via a number of inter-dependent regulatory mechanisms that enable these organisms to accommodate divergent growth modes. In order to maintain redox homeostasis, this bacterium possesses regulatory mechanisms functioning as electron sinks affecting the oxidation-reduction state of the ubiquinone pool. Under the photoheterotrophic growth conditions with reduced carbon sources, the excess reducing equivalents are primarily consumed via the reduction of CO{sub 2} through the Calvin-Benson-Bassham (CBB) pathway or by the reduction of protons into hydrogen with the use of dinitrogenase enzyme system. In this study, our aim was to develop strategies to funnel the excess reducing equivalents to nitrogenase-dependent hydrogen production by blocking the carbon-fixation pathway. To realize this purpose, CO{sub 2} fixation was blocked by inactivating the Phosphoribulokinase (PRK) of CBB pathway in wild type (MT1131), uptake-hydrogenase (YO3) and cyt cbb{sub 3} oxidase deficient (YO4) strains. The hydrogen production capacity of newly generated strains deficient in the Calvin-Benson-Bassham pathway were analyzed and compared with wild type strains. The results indicated that, the hydrogen production efficiency and capacity of R. capsulatus was further improved by directing the excess reducing equivalents to dinitrogenase-dependent hydrogen production. (orig.)

  14. Crystallization of a flavodoxin involved in nitrogen fixation in Rhodobacter capsulatus

    Energy Technology Data Exchange (ETDEWEB)

    Pérez-Dorado, Inmaculada [Grupo de Cristalografía Macromolecular y Biología Estructural, Instituto de Química-Física Rocasolano, CSIC, Serrano 119, 28006 Madrid (Spain); Bortolotti, Ana; Cortez, Néstor [Instituto de Biología Molecular y Celular de Rosario (Universidad Nacional de Rosario y CONICET), Suipacha 531, S2002LRK Rosario (Argentina); Hermoso, Juan A., E-mail: xjuan@iqfr.csic.es [Grupo de Cristalografía Macromolecular y Biología Estructural, Instituto de Química-Física Rocasolano, CSIC, Serrano 119, 28006 Madrid (Spain)

    2008-05-01

    The flavodoxin NifF from R. capsulatus, a candidate for nitrogenase reduction during nitrogen fixation, has been crystallized using the hanging-drop vapour-diffusion method. Preliminary X-ray data processing at 2.17 Å resolution allowed determination of the crystal system and unit-cell parameters. Flavodoxins are small electron-transfer proteins that contain one molecule of noncovalently bound flavin mononucleotide (FMN). The flavodoxin NifF from the photosynthetic bacterium Rhodobacter capsulatus is reduced by one electron from ferredoxin/flavodoxin:NADP(H) reductase and was postulated to be an electron donor to nitrogenase in vivo. NifF was cloned and overexpressed in Escherichia coli, purified and concentrated for crystallization using the hanging-drop vapour-diffusion method at 291 K. Crystals grew from a mixture of PEG 3350 and PEG 400 at pH 5.5 and belong to the tetragonal space group P4{sub 1}2{sub 1}2, with unit-cell parameters a = b = 66.49, c = 121.32 Å. X-ray data sets have been collected to 2.17 Å resolution.

  15. A novel nitrilase from Rhodobacter sphaeroides LHS-305: cloning, heterologous expression and biochemical characterization.

    Science.gov (United States)

    Wang, Hualei; Li, Guinan; Li, Mingyang; Wei, Dongzhi; Wang, Xuedong

    2014-01-01

    In this study, a novel nitrilase gene from Rhodobacter sphaeroides was cloned and overexpressed in Escherichia coli. The open reading frame of the nitrilase gene includes 969 base pairs, which encodes a putative polypeptide of 322 amino acid residues. The molecular weight of the purified native nitrilase was about 560 kDa determined by size exclusion chromatography. This nitrilase showed one single band on SDS-PAGE with a molecular weight of 40 kDa. This suggested that the native nitrilase consisted of 14 subunits with identical size. The optimal pH and temperature of the purified enzyme were 7.0 and 40 °C, respectively. The kinetic parameters V max and K m toward 3-cyanopyridine were 77.5 μmol min(-1) mg(-1) and 73.1 mmol/l, respectively. The enzyme can easily convert aliphatic nitrile and aromatic nitriles to their corresponding acids. Furthermore, this enzyme demonstrated regioselectivity in hydrolysis of aliphatic dinitriles. This specific characteristic makes this nitrilase have a great potential for commercial production of various cyanocarboxylic acids by hydrolyzing readily available dinitriles.

  16. A new nitrilase-producing strain named Rhodobacter sphaeroides LHS-305: biocatalytic characterization and substrate specificity.

    Science.gov (United States)

    Yang, Chunsheng; Wang, Xuedong; Wei, Dongzhi

    2011-12-01

    The characteristics of the new nitrilase-producing strain Rhodobacter sphaeroides LHS-305 were investigated. By investigating several parameters influencing nitrilase production, the specific cell activity was ultimately increased from 24.5 to 75.0 μmol g(-1) min(-1), and hereinto, the choice of inducer proved the most important factor. The aromatic nitriles (such as 3-cyanopyridine and benzonitrile) were found to be the most favorable substrates of the nitrilase by analyzing the substrate spectrum. It was speculated that the unsaturated carbon atom attached to the cyano group was crucial for this type of nitrilase. The value of apparent K (m), substrate inhibition constant, and product inhibition constant of the nitrilase against 3-cyanopyridine were 4.5 × 10(-2), 29.2, and 8.6 × 10(-3) mol L(-1), respectively. When applied in nicotinic acid preparation, the nitrilase is able to hydrolyze 200 mmol L(-1) 3-cyanopyridine with 93% conversion rate in 13 h by 6.1 g L(-1) cells (dry cell weight).

  17. Photodynamics of the small BLUF protein BlrB from Rhodobacter sphaeroides.

    Science.gov (United States)

    Zirak, P; Penzkofer, A; Schiereis, T; Hegemann, P; Jung, A; Schlichting, I

    2006-06-01

    The BLUF protein BlrB from the non-sulphur anoxyphototrophic purple bacterium Rhodobacter sphaeroides is characterized by absorption and emission spectroscopy. BlrB expressed from E. coli binding FAD, FMN, and riboflavin (called BrlB(I)) and recombinant BlrB containing only FAD (called BlrB(II)) are investigated. The dark-adapted proteins exist in two different receptor conformations (receptor states) with different sub-nanosecond fluorescence lifetimes (BLUF(r,f) and BLUF(r,sl)). Some of the flavin-cofactor (ca. 8%) is unbound in thermodynamic equilibrium with the bound cofactor. The two receptor conformations are transformed to putative signalling states (BLUF(s,f) and BLUF(s,sl)) of decreased fluorescence efficiency and shortened fluorescence lifetime by blue-light excitation. In the dark at room temperature both signalling states recover back to the initial receptor states with a time constant of about 2s. Quantum yields of signalling state formation of about 90% for BlrB(II) and about 40% for BlrB(I) were determined by intensity dependent transmission measurements. Extended blue-light excitation causes unbound flavin degradation (formation of lumichrome and lumiflavin-derivatives) and bound cofactor conversion to the semiquinone form. The flavin-semiquinone further reduces and the reduced flavin re-oxidizes back in the dark. A photo-dynamics scheme is presented and relevant quantum efficiencies and time constants are determined.

  18. Absorption and fluorescence spectroscopic characterization of BLUF domain of AppA from Rhodobacter sphaeroides

    Energy Technology Data Exchange (ETDEWEB)

    Zirak, P. [Institut II - Experimentelle und Angewandte Physik, Universitaet Regensburg, Universitaetstrasse 31, D-93053 Regensburg (Germany); Penzkofer, A. [Institut II - Experimentelle und Angewandte Physik, Universitaet Regensburg, Universitaetstrasse 31, D-93053 Regensburg (Germany)], E-mail: alfons.penzkofer@physik.uni-regensburg.de; Schiereis, T. [Institut fuer Biologie, Experimentelle Biophysik, Humboldt-Universitaet zu Berlin, Invalidenstrasse 42, D-10115 Berlin (Germany); Hegemann, P. [Institut fuer Biologie, Experimentelle Biophysik, Humboldt-Universitaet zu Berlin, Invalidenstrasse 42, D-10115 Berlin (Germany); Jung, A. [Max-Planck-Institut fuer medizinische Forschung, Abteilung Biomolekulare Mechanismen, Jahnstrasse 29, D-69120 Heidelberg (Germany); Schlichting, I. [Max-Planck-Institut fuer medizinische Forschung, Abteilung Biomolekulare Mechanismen, Jahnstrasse 29, D-69120 Heidelberg (Germany)

    2005-08-08

    The BLUF domain of the transcriptional anti-repressor protein AppA from the non-sulfur anoxyphototrophic purple bacterium Rhodobacter sphaeroides was characterized by absorption and emission spectroscopy. The BLUF domain constructs AppA{sub 148} (consisting of amino-acid residues 1-148) and AppA{sub 126} (amino-acid residues 1-126) are investigated. The cofactor of the investigated domains is found to consist of a mixture of the flavins riboflavin, FMN, and FAD. The dark-adapted domains exist in two different active receptor conformations (receptor states) with different sub-nanosecond fluorescence lifetimes (BLUF{sub r,f} and BLUF{sub r,sl}) and a small non-interacting conformation (BLUF{sub nc}). The active receptor conformations are transformed to putative signalling states (BLUF{sub s,f} and BLUF{sub s,sl}) of low fluorescence efficiency and picosecond fluorescence lifetime by blue-light excitation (light-adapted domains). In the dark at room temperature both signalling states recover back to the initial receptor states with a time constant of about 17 min. A quantum yield of signalling state formation of about 25% was determined by intensity dependent transmission measurements. A photo-cycle scheme is presented including photo-induced charge transfer complex formation, charge recombination, and protein binding pocket reorganisation.

  19. Absorption and fluorescence spectroscopic characterization of BLUF domain of AppA from Rhodobacter sphaeroides

    Science.gov (United States)

    Zirak, P.; Penzkofer, A.; Schiereis, T.; Hegemann, P.; Jung, A.; Schlichting, I.

    2005-08-01

    The BLUF domain of the transcriptional anti-repressor protein AppA from the non-sulfur anoxyphototrophic purple bacterium Rhodobacter sphaeroides was characterized by absorption and emission spectroscopy. The BLUF domain constructs AppA 148 (consisting of amino-acid residues 1-148) and AppA 126 (amino-acid residues 1-126) are investigated. The cofactor of the investigated domains is found to consist of a mixture of the flavins riboflavin, FMN, and FAD. The dark-adapted domains exist in two different active receptor conformations (receptor states) with different sub-nanosecond fluorescence lifetimes (BLUF r,f and BLUF r,sl) and a small non-interacting conformation (BLUF nc). The active receptor conformations are transformed to putative signalling states (BLUF s,f and BLUF s,sl) of low fluorescence efficiency and picosecond fluorescence lifetime by blue-light excitation (light-adapted domains). In the dark at room temperature both signalling states recover back to the initial receptor states with a time constant of about 17 min. A quantum yield of signalling state formation of about 25% was determined by intensity dependent transmission measurements. A photo-cycle scheme is presented including photo-induced charge transfer complex formation, charge recombination, and protein binding pocket reorganisation.

  20. Absorption and fluorescence spectroscopic characterization of BLUF domain of AppA from Rhodobacter sphaeroides

    International Nuclear Information System (INIS)

    Zirak, P.; Penzkofer, A.; Schiereis, T.; Hegemann, P.; Jung, A.; Schlichting, I.

    2005-01-01

    The BLUF domain of the transcriptional anti-repressor protein AppA from the non-sulfur anoxyphototrophic purple bacterium Rhodobacter sphaeroides was characterized by absorption and emission spectroscopy. The BLUF domain constructs AppA 148 (consisting of amino-acid residues 1-148) and AppA 126 (amino-acid residues 1-126) are investigated. The cofactor of the investigated domains is found to consist of a mixture of the flavins riboflavin, FMN, and FAD. The dark-adapted domains exist in two different active receptor conformations (receptor states) with different sub-nanosecond fluorescence lifetimes (BLUF r,f and BLUF r,sl ) and a small non-interacting conformation (BLUF nc ). The active receptor conformations are transformed to putative signalling states (BLUF s,f and BLUF s,sl ) of low fluorescence efficiency and picosecond fluorescence lifetime by blue-light excitation (light-adapted domains). In the dark at room temperature both signalling states recover back to the initial receptor states with a time constant of about 17 min. A quantum yield of signalling state formation of about 25% was determined by intensity dependent transmission measurements. A photo-cycle scheme is presented including photo-induced charge transfer complex formation, charge recombination, and protein binding pocket reorganisation

  1. Bioremediation of petroleum hydrocarbon contaminated soil by Rhodobacter sphaeroides biofertilizer and plants.

    Science.gov (United States)

    Jiao, Haihua; Luo, Jinxue; Zhang, Yiming; Xu, Shengjun; Bai, Zhihui; Huang, Zhanbin

    2015-09-01

    Bio-augmentation is a promising technique for remediation of polluted soils. This study aimed to evaluate the bio-augmentation effect of Rhodobacter sphaeroides biofertilizer (RBF) on the bioremediation of total petroleum hydrocarbons (TPH) contaminated soil. A greenhouse pot experiment was conducted over a period of 120 days, three methods for enhancing bio-augmentation were tested on TPH contaminated soils, including single addition RBF, planting, and combining of RBF and three crop species, such as wheat (W), cabbage (C) and spinach (S), respectively. The results demonstrated that the best removal of TPH from contaminated soil in the RBF bio-augmentation rhizosphere soils was found to be 46.2%, 65.4%, 67.5% for W+RBF, C+RBF, S+RBF rhizosphere soils respectively. RBF supply impacted on the microbial community diversity (phospholipid fatty acids, PLFA) and the activity of soil enzymes, such as dehydrogenase (DH), alkaline phosphatase (AP) and urease (UR). There were significant difference among the soil only containing crude oil (CK), W, C and S rhizosphere soils and RBF bio-augmentation soils. Moreover, the changes were significantly distinct depended on crops species. It was concluded that the RBF is a valuable material for improving effect of remediation of TPH polluted soils.

  2. Field evidence for the potential of Rhodobacter capsulatus as Biofertilizer for flooded rice.

    Science.gov (United States)

    Gamal-Eldin, Hosny; Elbanna, Khaled

    2011-02-01

    In a previous study, we evaluated the effects of inoculating rice plants with the phototrophic purple nonsulfur bacterium Rhodobacter capsulatus (Rc) on growth and yield of rice in pots and lysimeter experiments and the results obtained have been highly encouraging. In this study, we carried out two field experiments: one in the experimental farm of the Faculty of Agriculture, Fayoum University, and the second in a farmer's field in Kafr El-sheikh, to assess the effects of Rc on growth and yield of rice in comparison and in combination with chemical nitrogen fertilizer (CNF) and farmyard manure. The results indicated that both biological and grain yields in all the Rc inoculated treatments were significantly higher than those in the uninoculated corresponding treatments in both fields. With regard to grain yield, the major factor for determining the effectiveness of any agricultural treatment, inoculation with Rc in combination with 50% of the recommended CNF rate gave a grain yield that was statistically equivalent to that obtained with 100% of the recommended CNF rate. These results provide a clear evidence for the potential of Rc as biofertilizer for flooded rice under field conditions.

  3. Redox potential tuning through differential quinone binding in the photosynthetic reaction center of Rhodobacter sphaeroides.

    Science.gov (United States)

    Vermaas, Josh V; Taguchi, Alexander T; Dikanov, Sergei A; Wraight, Colin A; Tajkhorshid, Emad

    2015-03-31

    Ubiquinone forms an integral part of the electron transport chain in cellular respiration and photosynthesis across a vast number of organisms. Prior experimental results have shown that the photosynthetic reaction center (RC) from Rhodobacter sphaeroides is only fully functional with a limited set of methoxy-bearing quinones, suggesting that specific interactions with this substituent are required to drive electron transport and the formation of quinol. The nature of these interactions has yet to be determined. Through parameterization of a CHARMM-compatible quinone force field and subsequent molecular dynamics simulations of the quinone-bound RC, we have investigated and characterized the interactions of the protein with the quinones in the Q(A) and Q(B) sites using both equilibrium simulation and thermodynamic integration. In particular, we identify a specific interaction between the 2-methoxy group of ubiquinone in the Q(B) site and the amide nitrogen of GlyL225 that we implicate in locking the orientation of the 2-methoxy group, thereby tuning the redox potential difference between the quinones occupying the Q(A) and Q(B) sites. Disruption of this interaction leads to weaker binding in a ubiquinone analogue that lacks a 2-methoxy group, a finding supported by reverse electron transfer electron paramagnetic resonance experiments of the Q(A)⁻Q(B)⁻ biradical and competitive binding assays.

  4. Crystallization of a flavodoxin involved in nitrogen fixation in Rhodobacter capsulatus

    International Nuclear Information System (INIS)

    Pérez-Dorado, Inmaculada; Bortolotti, Ana; Cortez, Néstor; Hermoso, Juan A.

    2008-01-01

    The flavodoxin NifF from R. capsulatus, a candidate for nitrogenase reduction during nitrogen fixation, has been crystallized using the hanging-drop vapour-diffusion method. Preliminary X-ray data processing at 2.17 Å resolution allowed determination of the crystal system and unit-cell parameters. Flavodoxins are small electron-transfer proteins that contain one molecule of noncovalently bound flavin mononucleotide (FMN). The flavodoxin NifF from the photosynthetic bacterium Rhodobacter capsulatus is reduced by one electron from ferredoxin/flavodoxin:NADP(H) reductase and was postulated to be an electron donor to nitrogenase in vivo. NifF was cloned and overexpressed in Escherichia coli, purified and concentrated for crystallization using the hanging-drop vapour-diffusion method at 291 K. Crystals grew from a mixture of PEG 3350 and PEG 400 at pH 5.5 and belong to the tetragonal space group P4 1 2 1 2, with unit-cell parameters a = b = 66.49, c = 121.32 Å. X-ray data sets have been collected to 2.17 Å resolution

  5. Les jeux de hasard chez les enfants et les adolescents

    Science.gov (United States)

    Gupta, Rina; Pinzon, Jorge L

    2012-01-01

    RÉSUMÉ Même si, au Canada, les mineurs n’ont pas le droit de jouer à des jeux de hasard légalisés, les adolescents participent souvent à des jeux de hasard soit légalisés (produits de loterie, casino, terminaux de jeux vidéo), soit autonomes (jeux de cartes, paris sportifs, dés) à la maison et en milieu scolaire. Chez les adultes, le taux de prévalence de dépendance aux jeux de hasard au cours de la vie se situe entre 1 % et 2 %. D’après les données existantes, la prévalence chez les adolescents serait de deux à quatre fois plus élevée. On ne sait pas grand-chose des facteurs de risque d’apparition et de perpétuation d’une dépendance pathologique aux jeux de hasard. Le présent document de principes vise à informer les pédiatres, les médecins de famille et les autres professionnels de la santé des connaissances émergentes sur les jeux de hasard pendant l’enfance et l’adolescence et du risque de conséquences graves qui s’y rattachent. On y exhorte également les gouvernements fédéral, provinciaux et territoriaux à inclure cette question dans leur programme et à tenir compte des facteurs sociopolitiques associés aux jeux de hasard.

  6. Explorations of new selenites of the group IIIA and IVA metals

    International Nuclear Information System (INIS)

    Kong Fang; Li Peicin; Zhang Suyun; Mao Jianggao

    2012-01-01

    Systematic explorations of new phases in the Ga III /In III /Ge IV –Se IV –O systems by hydrothermal syntheses or solid-state reactions at high-temperature led to six new ternary compounds, namely, M 2 Se 2 O 7 (M=Ga 1, In 2), M(OH)(SeO 3 ) (M=Ga 3, In 4), α-Ge(SeO 3 ) 2 5 and β-Ge(SeO 3 ) 2 6. Ga 2 Se 2 O 7 1 displays a 3D open framework composed of 2D gallium oxide layers being further bridged and capped by SeO 3 groups. In 2 Se 2 O 7 2 features a 3D indium oxide framework formed by corner- and edge- sharing InO 6 octahedra with SeO 3 groups attached on the cavities and the 8-member ring tunnels of the structure. The isostructural of M(OH)(SeO 3 ) (M=Ga 3, In 4) exhibit a 2D metal selenite layer composed of 1D edge-sharing MO 6 octahedral chains that are interconnected by SeO 3 groups. α-Ge(SeO 3 ) 2 (P2 1 /n) 5 displays a 3D open framework with 1D 8-member ring tunnels along the a-axis while β-Ge(SeO 3 ) 2 (Pa-3) 6 exhibits a condensed 3D network. - Graphical abstract: Highlights: ► Up to now, selenites of the group IIIA and IVA metals are still rare. ► Hydrothermal or solid state reactions yielded six new compounds in this system. ► They are M 2 Se 2 O 7 (M=Ga, In), M(OH)(SeO 3 ) (M=Ga, In), α-Ge(SeO 3 ) 2 and β-Ge(SeO 3 ) 2 . ► They exhibit four different 3D and one 2D structural types. ► α-Ge(SeO 3 ) 2 and β-Ge(SeO 3 ) 2 represent the first examples of germanium selenites.

  7. Influence of dietary sodium selenite on tissue selenium levels of growing pigs

    International Nuclear Information System (INIS)

    Moksnes, K.; Tollersrud, S.; Larsen, H.J.

    1982-01-01

    Twenty Norwegian Landrace pigs were divided into 5 groups and fed a basal diet consisting of a mixture of dried skim milk and whey powder together with ground barley. The diet was supplemented with 0, 0.2, 0.8, 1.2, and 2.2 μg/g selenium as sodium selenite and was fed for 12 weeks. The muscle selenium level was increased by a factor of about 4 and the liver selenium by a factor of about 12 when the dietary selenium supplement was increased from zero to 2.2μg/g. There was a significant linear correlation between dietary selenium and selenium concentrations in tissues. Possible benefit for humans consuming meat from animals having received the selenium doses used in this experiment are discussed. (author)

  8. Effects of Foliar Selenite on the Nutrient Components of Turnip (Brassica rapa var. rapa Linn.

    Directory of Open Access Journals (Sweden)

    Xiong Li

    2018-03-01

    Full Text Available We administered foliar applications of 50, 100, and 200 mg L−1 selenium (Se, selenite on turnip (Brassica rapa var. rapa Linn. and detected the changes in the main nutrient components in fleshy roots. Results showed that the foliar application of Se (IV significantly increased the Se content in turnip, and Se (IV positively affected the uptake of several mineral elements, including magnesium, phosphorus, iron, zinc, manganese, and copper. Se (IV treatments also improved the synthesis of protein and multiple amino acids instead of crude fat and total carbohydrate in turnip, indicating that the foliar application of Se (IV could enhance Se biofortification in turnip and promote its nutritional value. We recommended 50–100 mg L−1 Se treatment for foliar application on turnip based on the daily intake of Se for adults (96–139 μg person−1 day−1 and its favorable effects on the nutrient components of turnip.

  9. Effects of foliar selenite on the nutrient components of turnip (Brassica rapa var. rapa Linn.)

    Science.gov (United States)

    Li, Xiong; Li, Boqun; Yang, Yongping

    2018-03-01

    We administered foliar applications of 50, 100 and 200 mg L‑1 selenium (Se, selenite) on turnip (Brassica rapa var. rapa Linn.) and detected the changes in the main nutrient components in fleshy roots. Results showed that the foliar application of Se (Ⅳ) significantly increased the Se content in turnip, and Se (Ⅳ) positively affected the uptake of several mineral elements, including magnesium, phosphorus, iron, zinc, manganese and copper. Se (Ⅳ) treatments also improved the synthesis of protein and multiple amino acids instead of crude fat and total carbohydrate in turnip, indicating that the foliar application of Se (Ⅳ) could enhance Se biofortification in turnip and promote its nutritional value. We recommended 50–100 mg L‑1 Se treatment for foliar application on turnip based on the daily intake of Se for adults (96–139 µg person‑1 day‑1) and its favourable effects on the nutrient components of turnip.

  10. Syntheses, structures and characterizations of three novel vanadium selenites with organically bonded copper/nickel complex

    International Nuclear Information System (INIS)

    Qian, Cheng; Kong, Fang; Mao, Jiang-Gao

    2016-01-01

    A series of vanadium selenites covalently bonded with metal-organic complex, namely, Ni(2,2-bipy) 2 V 2 O 4 (SeO 3 ) 2 (1), Cu(2,2-bipy)V 2 O 4 (SeO 3 ) 2 ·0.5H 2 O (2) and Cu 2 (2,2-bipy) 2 V 5 O 12 (SeO 3 ) 2 (3) (2,2-bipy=2,2-bipyridine) have been hydrothermally synthesized and structurally characterized. They exhibit three different structural dimensions, from 0D cluster, 1D chain to 2D layer. Compound 1 features a 0D {Ni(2,2-bipy) 2 V 2 O 4 (SeO 3 ) 2 } 2 dimeric cluster composed of two {Ni(2,2-bipy) 2 } 2+ moieties connected by the {V 4 O 8 (SeO 3 ) 4 } 4- cluster. Compound 2 shows a 1D {Cu(2,2-bipy)V 2 O 4 (SeO 3 ) 2 } n chain in which the {Cu 2 (2,2-bipy) 2 } 4+ moieties are bridged by the {V 4 O 8 (SeO 3 ) 4 } 4− clusters. Compound 3 displays a 2D structure consisted of mixed valence vanadium selenites layers {V IV V V 4 Se IV 2 O 18 } n 4− and {Cu(2,2-bipy)} 2+ complex moieties. The adjacent layers are further interconnected via π-π interactions between the 2,2-bipy ligands exhibiting an interesting 3D supramolecular architecture. Both compound 1 and 2 contain a new {V 4 O 8 (SeO 3 ) 4 } 4− cluster and compound 3 exhibits the first 2D vanadate polyhedral layer in vanadium selenites/tellurites with organic moieties. - Graphical abstract: We got three new vanadium selenites with organically linked copper/nickel complex, namely, Ni(2,2-bipy) 2 V 2 O 4 (SeO 3 ) 2 (1), Cu(2,2-bipy)V 2 O 4 (SeO 3 ) 2 ·0.5H 2 O (2) and Cu 2 (2,2-bipy) 2 V 5 O 12 (SeO 3 ) 2 (3) by hydrothermally syntheses. They display three different structural dimensions, from 0D cluster, to 1D chain and 2D layer. Display Omitted - Highlights: • Three new compounds display three different structural dimensions, from 0D cluster, to 1D chain and 2D layer. • The Tetranuclear {V 4 O 8 (SeO 3 ) 4 } 4− cluster and the vanadate {V 5 O 17 } n 2D layer are observed firstly. • Optical Properties and Magnetic Properties of three compounds are reported.

  11. Syntheses, structures and characterizations of three novel vanadium selenites with organically bonded copper/nickel complex

    Energy Technology Data Exchange (ETDEWEB)

    Qian, Cheng [College of Chemistry, Fuzhou University, Fuzhou, Fujian 350002 (China); State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China); Kong, Fang [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China); Mao, Jiang-Gao, E-mail: mjg@fjirsm.ac.cn [College of Chemistry, Fuzhou University, Fuzhou, Fujian 350002 (China); State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou 350002 (China)

    2016-06-15

    A series of vanadium selenites covalently bonded with metal-organic complex, namely, Ni(2,2-bipy){sub 2}V{sub 2}O{sub 4}(SeO{sub 3}){sub 2} (1), Cu(2,2-bipy)V{sub 2}O{sub 4}(SeO{sub 3}){sub 2}·0.5H{sub 2}O (2) and Cu{sub 2}(2,2-bipy){sub 2}V{sub 5}O{sub 12}(SeO{sub 3}){sub 2} (3) (2,2-bipy=2,2-bipyridine) have been hydrothermally synthesized and structurally characterized. They exhibit three different structural dimensions, from 0D cluster, 1D chain to 2D layer. Compound 1 features a 0D {Ni(2,2-bipy)_2V_2O_4(SeO_3)_2}{sub 2} dimeric cluster composed of two {Ni(2,2-bipy)_2}{sup 2+} moieties connected by the {V_4O_8(SeO_3)_4}{sup 4-} cluster. Compound 2 shows a 1D {Cu(2,2-bipy)V_2O_4(SeO_3)_2}{sub n} chain in which the {Cu_2(2,2-bipy)_2}{sup 4+} moieties are bridged by the {V_4O_8(SeO_3)_4}{sup 4−} clusters. Compound 3 displays a 2D structure consisted of mixed valence vanadium selenites layers {V"I"VV"V_4Se"I"V_2O_1_8}{sub n}{sup 4−} and {Cu(2,2-bipy)}{sup 2+} complex moieties. The adjacent layers are further interconnected via π-π interactions between the 2,2-bipy ligands exhibiting an interesting 3D supramolecular architecture. Both compound 1 and 2 contain a new {V_4O_8(SeO_3)_4}{sup 4−} cluster and compound 3 exhibits the first 2D vanadate polyhedral layer in vanadium selenites/tellurites with organic moieties. - Graphical abstract: We got three new vanadium selenites with organically linked copper/nickel complex, namely, Ni(2,2-bipy){sub 2}V{sub 2}O{sub 4}(SeO{sub 3}){sub 2} (1), Cu(2,2-bipy)V{sub 2}O{sub 4}(SeO{sub 3}){sub 2}·0.5H{sub 2}O (2) and Cu{sub 2}(2,2-bipy){sub 2}V{sub 5}O{sub 12}(SeO{sub 3}){sub 2} (3) by hydrothermally syntheses. They display three different structural dimensions, from 0D cluster, to 1D chain and 2D layer. Display Omitted - Highlights: • Three new compounds display three different structural dimensions, from 0D cluster, to 1D chain and 2D layer. • The Tetranuclear {V_4O_8(SeO_3)_4}{sup 4−} cluster and the vanadate {V

  12. Use of 75Se-labelled selenite ion for metabolic studies in various animal species

    International Nuclear Information System (INIS)

    Rico, A.G.; Benard, P.; Braun, J.P.

    1976-01-01

    This work was carried out by autoradiography (mice, pigs) and liquid scintillation (rats, rabbits, pigs, ewes). The results obtained show that after intramuscular administration sodium selenite is rapidly absorbed. It is distributed in the different organs, preferentially in the liver, kidney, bone-marrow and heart, where it remains fixed for a long time. In the blood it decreases only slowly. Much of the selenium is excreted, partly during the first 48 hours in urine (20-30%, depending on species), mainly in the seleniate form, and partly in the faecal matter, the latter type of excretion being spread over a longer time (5-8 days). Transfer to milk in the ewes is only slight. From these results it can be stated with certainty that the selenium that is not excreted during the first few hours in the urine or faeces is translocated to the cell structure, particularly the proteic structures. Its chemical relationship to sulphur easily explains this metabolic peculiarity. (author)

  13. New indium selenite-oxalate and indium oxalate with two- and three-dimensional structures

    International Nuclear Information System (INIS)

    Cao Junjun; Li Guodong; Chen Jiesheng

    2009-01-01

    Two new indium(III) compounds with extended structures, [In 2 (SeO 3 ) 2 (C 2 O 4 )(H 2 O) 2 ].2H 2 O (I) and [NH 3 (CH 2 ) 2 NH 3 ][In(C 2 O 4 ) 2 ] 2 .5H 2 O (II), have been prepared under mild hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction, thermogravimetric analysis and infrared spectroscopy. Compound I crystallizes in the triclinic system, space group P-1, with a=5.2596(11) A, b=6.8649(14) A, c=9.3289(19) A, α=101.78(3) o , β=102.03(3) o , γ=104.52(3) o , while compound II crystallizes in the orthorhombic system, space group Fdd2, with a=15.856(3) A, b=31.183(6) A, c=8.6688(17) A. In compound I, indium-selenite chains are bridged by oxalate units to form two-dimensional (2D) In 2 (SeO 3 ) 2 C 2 O 4 layers, separated by non-coordinating water molecules. In compound II, the indium atoms are connected through the oxalate units to generate a 3D open framework containing cross-linked 12- and 8-membered channels. - Graphical abstract: Two new indium(III) compounds have been hydrothermally synthesized and structurally characterized. In I, the indium-selenite chains are bridged by oxalate units to form 2D In 2 (SeO 3 ) 2 C 2 O 4 layers. In II, the indium atoms are connected through the oxalate units to generate a 3D open framework containing cross-linked 12- and 8-membered ring channels

  14. Effects of Sodium Selenite on Formaldehyde Induced Renal Toxicity in Mice

    Directory of Open Access Journals (Sweden)

    Shabnam Mohammadi 1,2 * , Maryam Moghimian 3, Hanieh Torabzadeh 4, Mahla Langari 4, Roghayeh Nazeri 4, Zahra Karimi 4, Elham Sangari 4, Najmeh Jagarmi 5, Alireza Mohammad Zadeh 3, Mehdi Karimi 7, Kamyar Tavakkoli 8, Ali Delshad 9, Fatemeh Mohammadzadeh 3, Majid Ghayour-Mobarhan 10

    2016-12-01

    Full Text Available Background: Formaldehyde is widely used for industrial applications. Renal injury is an adverse effect associated with formaldehyde. Few studies have explored the potential benefits of protective factors on formaldehyde induced renal toxicity. This study evaluated the dose dependent effects of sodium selenite on the biochemical and histopathological effects of formaldehyde on murine kidney. Methods: Forty eight adult Balb/c male mice were randomized into six groups: a control group, a formaldehyde group and experimental III-VI groups. Formaldehyde group was injected with 10 mg/kg formaldehyde and groups III-VI received intraperitoneally doses of 0.1, 0.2, 0.4, 0.8 mg/kg selenium. After two weeks, a stereological study was done in accordance with the principle of Cavalieri and serum concentrations of urea and creatinine were measured. Data were analyzed using ANOVA and SPSS software. Results: Glomerosclerosis, necrosis and vacuolization were observed in the convoluted tubules of animals treated with formaldehyde. The biochemical markers, volume and count of glomeruli in the group treated with formaldehyde was significantly difference compared to the control group (P<0.05. The volume of the glomeruli in the group treated with 0.2 and 0.4 mg selenium and urea level in the group treated with 0.4 and 0.1 mg/kg selenium was significantly difference compared to the control group (P <0.05. The count of glomeruli and creatinine level in the selenium group was significantly difference compared to the control group (P ≤ 0.0001. Conclusions: A dose of 0.2 mg/kg of sodium selenite caused partial protective effect on the renal tissue and function in exposed to formaldehyde.

  15. Connectivity of the intracytoplasmic membrane of Rhodobacter sphaeroides: a functional approach.

    Science.gov (United States)

    Verméglio, André; Lavergne, Jérôme; Rappaport, Fabrice

    2016-01-01

    The photosynthetic apparatus in the bacterium Rhodobacter sphaeroides is mostly present in intracytoplasmic membrane invaginations. It has long been debated whether these invaginations remain in topological continuity with the cytoplasmic membrane, or form isolated chromatophore vesicles. This issue is revisited here by functional approaches. The ionophore gramicidin was used as a probe of the relative size of the electro-osmotic units in isolated chromatophores, spheroplasts, or intact cells. The decay of the membrane potential was monitored from the electrochromic shift of carotenoids. The half-time of the decay induced by a single channel in intact cells was about 6 ms, thus three orders of magnitude slower than in isolated chromatophores. In spheroplasts obtained by lysis of the cell wall, the single channel decay was still slower (~23 ms) and the sensitivity toward the gramicidin concentration was enhanced 1,000-fold with respect to isolated chromatophores. These results indicate that the area of the functional membrane in cells or spheroplasts is about three orders of magnitude larger than that of isolated chromatophores. Intracytoplasmic vesicles, if present, could contribute to at most 10% of the photosynthetic apparatus in intact cells of Rba. sphaeroides. Similar conclusions were obtained from the effect of a ∆pH-induced diffusion potential in intact cells. This caused a large electrochromic response of carotenoids, of similar amplitude as the light-induced change, indicating that most of the system is sensitive to a pH change of the external medium. A single internal membrane and periplasmic space may offer significant advantages concerning renewal of the photosynthetic apparatus and reallocation of the components shared with other bioenergetic pathways.

  16. The organization of LH2 complexes in membranes from Rhodobacter sphaeroides.

    Science.gov (United States)

    Olsen, John D; Tucker, Jaimey D; Timney, John A; Qian, Pu; Vassilev, Cvetelin; Hunter, C Neil

    2008-11-07

    The mapping of the photosynthetic membrane of Rhodobacter sphaeroides by atomic force microscopy (AFM) revealed a unique organization of arrays of dimeric reaction center-light harvesting I-PufX (RC-LH1-PufX) core complexes surrounded and interconnected by light-harvesting LH2 complexes (Bahatyrova, S., Frese, R. N., Siebert, C. A., Olsen, J. D., van der Werf, K. O., van Grondelle, R., Niederman, R. A., Bullough, P. A., Otto, C., and Hunter, C. N. (2004) Nature 430, 1058-1062). However, membrane regions consisting solely of LH2 complexes were under-represented in these images because these small, highly curved areas of membrane rendered them difficult to image even using gentle tapping mode AFM and impossible with contact mode AFM. We report AFM imaging of membranes prepared from a mutant of R. sphaeroides, DPF2G, that synthesizes only the LH2 complexes, which assembles spherical intracytoplasmic membrane vesicles of approximately 53 nm diameter in vivo. By opening these vesicles and adsorbing them onto mica to form small, LH2-only membranes for the first time. The transition from highly curved vesicle to the planar sheet is accompanied by a change in the packing of the LH2 complexes such that approximately half of the complexes are raised off the mica surface by approximately 1 nm relative to the rest. This vertical displacement produces a very regular corrugated appearance of the planar membrane sheets. Analysis of the topographs was used to measure the distances and angles between the complexes. These data are used to model the organization of LH2 complexes in the original, curved membrane. The implications of this architecture for the light harvesting function and diffusion of quinones in native membranes of R. sphaeroides are discussed.

  17. Photo dynamics of BLUF domain mutant H44R of AppA from Rhodobacter sphaeroides

    International Nuclear Information System (INIS)

    Zirak, P.; Penzkofer, A.; Hegemann, P.; Mathes, T.

    2007-01-01

    The photo-cycle dynamics of the H44R mutant of the BLUF domain of the transcriptional anti-repressor protein AppA (AppA-H44R) from the non-sulfur anoxyphototropic purple bacterium Rhodobacter sphaeroides is studied in order to gain information on the involvement of His44 in the photo-cyclic mechanism of the AppA BLUF domain and to add information to the involved processes. The amino acid residue histidine at position 44 is replaced by arginine. A 12 nm red-shifted signalling state is formed upon blue-light excitation, while in wild-type AppA (AppA-wt) the red-shift is 16 nm. The recovery to the receptor dark state is approximately a factor of 2.5 faster (τ rec ∼ 6.5 min) than the recovery of the wild-type counterpart. Extended light exposure of the mutant causes photo-degradation of flavin (mainly free flavin conversion to lumichrome and re-equilibration between free and non-covalently bound flavin) and protein aggregation (showing up as light scattering). No photo-degradation was observed for AppA-wt. The quantum efficiency of signalling-state formation determined by intensity dependent absorption measurements is found to be φ s ∼ 0.3 (for AppA-wt: φ s ∼ 0.24). A two-component single-exponential fluorescence relaxation was observed, which is interpreted as fast fluorescence quenching to an equilibrium value by photo-induced electron transfer followed by slower fluorescence decay due to charge recombination. Based on the experimental findings, an extended photo-cycle model for BLUF domains is proposed

  18. Rhodobacter capsulatus gains a competitive advantage from respiratory nitrate reduction during light-dark transitions.

    Science.gov (United States)

    Ellington, M J K; Richardson, D J; Ferguson, S J

    2003-04-01

    Rhodobacter capsulatus N22DNAR(+) possesses a periplasmic nitrate reductase and is capable of reducing nitrate to nitrite under anaerobic conditions. In the absence of light this ability cannot support chemoheterotrophic growth in batch cultures. This study investigated the effect of nitrate reduction on the growth of R. capsulatus N22DNAR(+) during multiple light-dark cycles of anaerobic photoheterotrophic/dark chemoheterotrophic growth conditions in carbon-limited continuous cultures. The reduction of nitrate did not affect the photoheterotrophic growth yield of R. capsulatus N22DNAR(+). After a transition from photoheterotrophic to dark chemoheterotrophic growth conditions, the reduction of nitrate slowed the initial washout of a R. capsulatus N22DNAR(+) culture. Towards the end of a period of darkness nitrate-reducing cultures maintained higher viable cell counts than non-nitrate-reducing cultures. During light-dark cycling of a mixed culture, the strain able to reduce nitrate (N22DNAR(+)) outcompeted the strain which was unable to reduce nitrate (N22). The evidence indicates that the periplasmic nitrate reductase activity supports slow growth that retards the washout of a culture during anaerobic chemoheterotrophic conditions, and provides a protonmotive force for cell maintenance during the dark period before reillumination. This translates into a selective advantage during repeated light-dark cycles, such that in mixed culture N22DNAR(+) outcompetes N22. Exposure to light-dark cycles will be a common feature for R. capsulatus in its natural habitats, and this study shows that nitrate respiration may provide a selective advantage under such conditions.

  19. Reprint of “Extracellular production of tellurium nanoparticles by the photosynthetic bacterium Rhodobacter capsulatus”

    Energy Technology Data Exchange (ETDEWEB)

    Borghese, Roberto, E-mail: roberto.borghese@unibo.it [Dept. of Pharmacy and Biotechnology, University of Bologna (Italy); Brucale, Marco [Institute for the Study of Nanostructured Materials (CNR-ISMN), Rome (Italy); Fortunato, Gianuario [Dept. of Pharmacy and Biotechnology, University of Bologna (Italy); Lanzi, Massimiliano [Dept. of Industrial Chemistry “Toso Montanari”, University of Bologna (Italy); Mezzi, Alessio [Institute for the Study of Nanostructured Materials (CNR-ISMN), Rome (Italy); Valle, Francesco; Cavallini, Massimiliano [Institute for the Study of Nanostructured Materials (CNR-ISMN), Bologna (Italy); Zannoni, Davide [Dept. of Pharmacy and Biotechnology, University of Bologna (Italy)

    2017-02-15

    Highlights: • Tellurite is reduced by R. capsulatus as cytosolic tellurium nanoprecipitates TeNPs. • Lawsone allows R. capsulatus to produce extracellular TeNPs. • Extracellular TeNPs production depends on the carbon source used for cells growth. • Both lawsone concentration and the incubation time determine the TeNPs size. • Extracellular TeNPs are coated with extracellular polymeric substances (EPS). - Abstract: The toxic oxyanion tellurite (TeO{sub 3}{sup 2−}) is acquired by cells of Rhodobacter capsulatus grown anaerobically in the light, via acetate permease ActP2 and then reduced to Te{sup 0} in the cytoplasm as needle-like black precipitates. Interestingly, photosynthetic cultures of R. capsulatus can also generate Te{sup 0} nanoprecipitates (TeNPs) outside the cells upon addition of the redox mediator lawsone (2-hydroxy-1,4-naphtoquinone). TeNPs generation kinetics were monitored to define the optimal conditions to produce TeNPs as a function of various carbon sources and lawsone concentration. We report that growing cultures over a 10 days period with daily additions of 1 mM tellurite led to the accumulation in the growth medium of TeNPs with dimensions from 200 up to 600–700 nm in length as determined by atomic force microscopy (AFM). This result suggests that nucleation of TeNPs takes place over the entire cell growth period although the addition of new tellurium Te{sup 0} to pre-formed TeNPs is the main strategy used by R. capsulatus to generate TeNPs outside the cells. Finally, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FT-IR) analysis of TeNPs indicate they are coated with an organic material which keeps the particles in solution in aqueous solvents.

  20. Bioremediation of cadmium- and zinc-contaminated soil using Rhodobacter sphaeroides.

    Science.gov (United States)

    Peng, Weihua; Li, Xiaomin; Song, Jingxiang; Jiang, Wei; Liu, Yingying; Fan, Wenhong

    2018-04-01

    Bioremediation using microorganisms is a promising technique to remediate soil contaminated with heavy metals. In this study, Rhodobacter sphaeroides was used to bioremediate soils contaminated with cadmium (Cd) and zinc (Zn). The study found that the treatment reduced the overall bioavailable fractions (e.g., exchangeable and carbonate bound phases) of Cd and Zn. More stable fractions (e.g., Fe-Mn oxide, organic bound, and residual phases (only for Zn)) increased after bioremediation. A wheat seedling experiment revealed that the phytoavailability of Cd was reduced after bioremediation using R. sphaeroides. After bioremediation, the exchangeable phases of Cd and Zn in soil were reduced by as much as 30.7% and 100.0%, respectively; the Cd levels in wheat leaf and root were reduced by as much as 62.3% and 47.2%, respectively. However, when the soils were contaminated with very high levels of Cd and Zn (Cd 54.97-65.33 mg kg -1 ; Zn 813.4-964.8 mg kg -1 ), bioremediation effects were not clear. The study also found that R. sphaeroides bioremediation in soil can enhance the Zn/Cd ratio in the harvested wheat leaf and root overall. This indicates potentially favorable application in agronomic practice and biofortification. Although remediation efficiency in highly contaminated soil was not significant, R. sphaeroides may be potentially and practically applied to the bioremediation of soils co-contaminated by Cd and Zn. Copyright © 2018 Elsevier Ltd. All rights reserved.

  1. Cloning, DNA sequence, and expression of the Rhodobacter sphaeroides cytochrome c/sub 2/ gene

    Energy Technology Data Exchange (ETDEWEB)

    Donohue, T.J.; McEwan, A.G.; Kaplan, S.

    1986-11-01

    The Rhodobacter sphaeroides cytochrome c/sub 2/ functions as a mobile electron carrier in both aerobic and photosynthetic electron transport chains. Synthetic deoxyoligonucleotide probes, based on the known amino acid sequence of this protein (M/sub r/ 14,000), were used to identify and clone the cytochrome c/sub 2/ structural gene (cycA). DNA sequence analysis of the cycA gene indicated the presence of a typical procaryotic 21-residue signal sequence, suggesting that this periplasmic protein is synthesized in vivo as a precursor. Synthesis of an immunoreactive cytochrome c/sub 2/ precursor protein (M/sub r/ 15,500) was observed in vitro when plasmids containing the cycA gene were used as templates in an R. sphaeroides coupled transcription-translation system. Approximately 500 base pairs of DNA upstream of the cycA gene was sufficient to allow expression of this gene product in vitro. Northern blot analysis with an internal cycA-specific probe identified at least two possibly monocistronic transcripts present in both different cellular levels and relative stoichiometries in steady-state cells grown under different physiological conditions. The ratio of the small (740-mucleotide) and large (920-nucleotide) cycA-specific mRNA species was dependent on cultural conditions but was not affected by light intensity under photosynthetic conditions. These results suggest that the increase in the cellular level of the cytochrome c/sub 2/ protein found in photosynthetic cells was due, in part, to increased transcription of the single-copy cyc operon.

  2. Photo dynamics of BLUF domain mutant H44R of AppA from Rhodobacter sphaeroides

    Energy Technology Data Exchange (ETDEWEB)

    Zirak, P. [Institut II - Experimentelle und Angewandte Physik, Universitaet Regensburg, Universitaetstrasse 31, D-93053 Regensburg (Germany); Penzkofer, A. [Institut II - Experimentelle und Angewandte Physik, Universitaet Regensburg, Universitaetstrasse 31, D-93053 Regensburg (Germany)], E-mail: alfons.penzkofer@physik.uni-regensburg.de; Hegemann, P.; Mathes, T. [Institut fuer Biologie, Experimentelle Biophysik, Humboldt-Universitaet zu Berlin, Invalidenstr. 42, D-10115 Berlin (Germany)

    2007-05-21

    The photo-cycle dynamics of the H44R mutant of the BLUF domain of the transcriptional anti-repressor protein AppA (AppA-H44R) from the non-sulfur anoxyphototropic purple bacterium Rhodobacter sphaeroides is studied in order to gain information on the involvement of His44 in the photo-cyclic mechanism of the AppA BLUF domain and to add information to the involved processes. The amino acid residue histidine at position 44 is replaced by arginine. A 12 nm red-shifted signalling state is formed upon blue-light excitation, while in wild-type AppA (AppA-wt) the red-shift is 16 nm. The recovery to the receptor dark state is approximately a factor of 2.5 faster ({tau}{sub rec} {approx} 6.5 min) than the recovery of the wild-type counterpart. Extended light exposure of the mutant causes photo-degradation of flavin (mainly free flavin conversion to lumichrome and re-equilibration between free and non-covalently bound flavin) and protein aggregation (showing up as light scattering). No photo-degradation was observed for AppA-wt. The quantum efficiency of signalling-state formation determined by intensity dependent absorption measurements is found to be {phi}{sub s} {approx} 0.3 (for AppA-wt: {phi}{sub s} {approx} 0.24). A two-component single-exponential fluorescence relaxation was observed, which is interpreted as fast fluorescence quenching to an equilibrium value by photo-induced electron transfer followed by slower fluorescence decay due to charge recombination. Based on the experimental findings, an extended photo-cycle model for BLUF domains is proposed.

  3. Photo dynamics of BLUF domain mutant H44R of AppA from Rhodobacter sphaeroides

    Science.gov (United States)

    Zirak, P.; Penzkofer, A.; Hegemann, P.; Mathes, T.

    2007-05-01

    The photo-cycle dynamics of the H44R mutant of the BLUF domain of the transcriptional anti-repressor protein AppA (AppA-H44R) from the non-sulfur anoxyphototropic purple bacterium Rhodobacter sphaeroides is studied in order to gain information on the involvement of His44 in the photo-cyclic mechanism of the AppA BLUF domain and to add information to the involved processes. The amino acid residue histidine at position 44 is replaced by arginine. A 12 nm red-shifted signalling state is formed upon blue-light excitation, while in wild-type AppA (AppA-wt) the red-shift is 16 nm. The recovery to the receptor dark state is approximately a factor of 2.5 faster ( τrec ≈ 6.5 min) than the recovery of the wild-type counterpart. Extended light exposure of the mutant causes photo-degradation of flavin (mainly free flavin conversion to lumichrome and re-equilibration between free and non-covalently bound flavin) and protein aggregation (showing up as light scattering). No photo-degradation was observed for AppA-wt. The quantum efficiency of signalling-state formation determined by intensity dependent absorption measurements is found to be ϕs ≈ 0.3 (for AppA-wt: ϕs ≈ 0.24). A two-component single-exponential fluorescence relaxation was observed, which is interpreted as fast fluorescence quenching to an equilibrium value by photo-induced electron transfer followed by slower fluorescence decay due to charge recombination. Based on the experimental findings, an extended photo-cycle model for BLUF domains is proposed.

  4. Reusing pulp and paper mill effluent as a bioresource to produce biohydrogen through ultrasonicated Rhodobacter sphaeroides

    International Nuclear Information System (INIS)

    Hay, Jacqueline Xiao Wen; Wu, Ta Yeong; Ng, Boon Junn; Juan, Joon Ching; Md Jahim, Jamaliah

    2016-01-01

    Highlights: • Ultrasonication pretreatment on R. sphaeroides enhanced biohydrogen production. • Pretreatment using amplitude 30% for 10 min gave the highest biohydrogen yield. • Pretreatment using amplitude 45% for 15 min inhibited biohydrogen production. - Abstract: Pulp and paper industry is a water-intensive industry. This industry commonly produces considerable amount of effluent, especially from virgin raw materials processing. The effluent, namely pulp and paper mill effluent has the potential to adversely affect the receiving watercourses. However, the nutrients in the pulp and paper mill effluent could be reused as a substrate in biohydrogen production. In this study, photofermentative biohydrogen production was investigated using Rhodobacter sphaeroides and pulp and paper mill effluent as a substrate. An application of low power ultrasound on R. sphaeroides was predicted to increase photofermentative biohydrogen production but excessive ultrasound effects might inhibit the production due to possible cell disruption. Hence, various ultrasonication duration (5, 10 and 15 min) and amplitude (15%, 30% and 45%) were applied on the bacteria to determine the recommended ultrasonication conditions for improving biohydrogen production. The recommended conditions were operated at ultrasonication amplitude and duration of 30% and 10 min, respectively. A maximum biohydrogen yield of 9.62 mL bioH_2/mL medium was obtained under this condition, which was 66.7% higher than the result obtained using R. sphaeroides without undergoing ultrasonication (control). The light efficiency and cell concentration were increased by 67% and 150%, respectively, using ultrasonication amplitude and duration of 30% and 10 min, respectively as compared to the control. The present results demonstrated that moderate power of ultrasonication applied on R. sphaeroides was an effective method for enhancing photofermentative biohydrogen production using raw pulp and paper mill effluent as a

  5. Electrostatic dominoes: long distance propagation of mutational effects in photosynthetic reaction centers of Rhodobacter capsulatus.

    Science.gov (United States)

    Sebban, P; Maróti, P; Schiffer, M; Hanson, D K

    1995-07-04

    Two point mutants from the purple bacterium Rhodobacter capsulatus, both modified in the M protein of the photosynthetic reaction center, have been studied by flash-induced absorbance spectroscopy. These strains carry either the M231Arg --> Leu or M43ASN --> Asp mutations, which are located 9 and 15 A, respectively, from the terminal electron acceptor QB. In the wild-type Rb. sphaeroides structure, M231Arg is involved in a conserved salt bridge with H125Glu and H232Glu and M43Asn is located among several polar residues that form or surround the QB binding site. These substitutions were originally uncovered in phenotypic revertants isolated from the photosynthetically incompetent L212Glu-L213Asp --> Ala-Ala site-specific double mutant. As second-site suppressor mutations, they have been shown to restore the proton transfer function that is interrupted in the L212Ala-L213Ala double mutant. The electrostatic effects that are induced in reaction centers by the M231Arg --> Leu and M43Asn --> Asp substitutions are roughly the same in either the double-mutant or wild-type backgrounds. In a reaction center that is otherwise wild type in sequence, they decrease the free energy gap between the QA- and QB- states by 24 +/- 5 and 45 +/- 5 meV, respectively. The pH dependences of K2, the QA-QB QAQB- equilibrium constant, are altered in reaction centers that carry either of these substitutions, revealing differences in the pKas of titratable groups compared to the wild type.(ABSTRACT TRUNCATED AT 250 WORDS)

  6. Molecular genetic and molecular evolutionary studies on the bacteriochlorophyll synthesis genes of Rhodobacter capsulatus

    Energy Technology Data Exchange (ETDEWEB)

    Burke-Agueero, D.H.

    1992-08-01

    Rhodobacter capsulatus, purple bacterium capable of either aerobic or photosynthetic growth, has proven to be very useful in genetic studies of photosynthesis. Forty-four genes clustered together within a 46 kilobase region are required to establish photosynthetic ability in R. capsulatus. Approximately twenty of these genes are involved in bacteriochlorophyll synthesis of which eight bch'' genes are the subject of this thesis. Six of these genes were found to code for the two ring reductases. The first converts protochlorophyllide (PChlide) into a chlorin, the immediate precursor to chlorophyll a, and then into a bacteriochlorin. Each reductase is shown to be made up of three subunits. PChlide reductase is coded by the genes bchN, bchB, and bchL. Proteins with amino acid sequences markedly similar to those of bchN and bchL have been shown in other organisms to be required for chlorophyll synthesis; hence, their designation as chlN and chlB. A third chloroplast-encoded gene of heretofore unknown function shares amino acid identities with bchB and is probably the third subunit of the plant PChlide reductase. The bchA locus, which encodes the chlorin reductase, is found to be made up of three separate, translationally coupled genes, referred to as bchX, bchY, and bchZ. Amino acid similarities between bchX, bchL, and the nitrogenase reductase protein nifH suggest that all three classes of proteins share certain three-dimensional structural features, including elements that are central to the enzymatic mechanism of nifH. PChlide reductase and chlorin reductase are clearly derived from a common ancestor. Several lines of analysis suggests the ancestor of both enzyme systems reduced PChlide twice to produce bacteriochlorophyll supporting the concept bacteriochlorophyll as the ancestral reaction center pigment.

  7. Molecular genetic and molecular evolutionary studies on the bacteriochlorophyll synthesis genes of Rhodobacter capsulatus

    Energy Technology Data Exchange (ETDEWEB)

    Burke-Agueero, Donald H. [Univ. of California, Berkeley, CA (United States)

    1992-08-01

    Rhodobacter capsulatus, purple bacterium capable of either aerobic or photosynthetic growth, has proven to be very useful in genetic studies of photosynthesis. Forty-four genes clustered together within a 46 kilobase region are required to establish photosynthetic ability in R. capsulatus. Approximately twenty of these genes are involved in bacteriochlorophyll synthesis of which eight ``bch`` genes are the subject of this thesis. Six of these genes were found to code for the two ring reductases. The first converts protochlorophyllide (PChlide) into a chlorin, the immediate precursor to chlorophyll a, and then into a bacteriochlorin. Each reductase is shown to be made up of three subunits. PChlide reductase is coded by the genes bchN, bchB, and bchL. Proteins with amino acid sequences markedly similar to those of bchN and bchL have been shown in other organisms to be required for chlorophyll synthesis; hence, their designation as chlN and chlB. A third chloroplast-encoded gene of heretofore unknown function shares amino acid identities with bchB and is probably the third subunit of the plant PChlide reductase. The bchA locus, which encodes the chlorin reductase, is found to be made up of three separate, translationally coupled genes, referred to as bchX, bchY, and bchZ. Amino acid similarities between bchX, bchL, and the nitrogenase reductase protein nifH suggest that all three classes of proteins share certain three-dimensional structural features, including elements that are central to the enzymatic mechanism of nifH. PChlide reductase and chlorin reductase are clearly derived from a common ancestor. Several lines of analysis suggests the ancestor of both enzyme systems reduced PChlide twice to produce bacteriochlorophyll supporting the concept bacteriochlorophyll as the ancestral reaction center pigment.

  8. The prevalence of gene duplications and their ancient origin in Rhodobacter sphaeroides 2.4.1

    Directory of Open Access Journals (Sweden)

    Cho Hyuk

    2010-12-01

    Full Text Available Abstract Background Rhodobacter sphaeroides 2.4.1 is a metabolically versatile organism that belongs to α-3 subdivision of Proteobacteria. The present study was to identify the extent, history, and role of gene duplications in R. sphaeroides 2.4.1, an organism that possesses two chromosomes. Results A protein similarity search (BLASTP identified 1247 orfs (~29.4% of the total protein coding orfs that are present in 2 or more copies, 37.5% (234 gene-pairs of which exist in duplicate copies. The distribution of the duplicate gene-pairs in all Clusters of Orthologous Groups (COGs differed significantly when compared to the COG distribution across the whole genome. Location plots revealed clusters of gene duplications that possessed the same COG classification. Phylogenetic analyses were performed to determine a tree topology predicting either a Type-A or Type-B phylogenetic relationship. A Type-A phylogenetic relationship shows that a copy of the protein-pair matches more with an ortholog from a species closely related to R. sphaeroides while a Type-B relationship predicts the highest match between both copies of the R. sphaeroides protein-pair. The results revealed that ~77% of the proteins exhibited a Type-A phylogenetic relationship demonstrating the ancient origin of these gene duplications. Additional analyses on three other strains of R. sphaeroides revealed varying levels of gene loss and retention in these strains. Also, analyses on common gene pairs among the four strains revealed that these genes experience similar functional constraints and undergo purifying selection. Conclusions Although the results suggest that the level of gene duplication in organisms with complex genome structuring (more than one chromosome seems to be not markedly different from that in organisms with only a single chromosome, these duplications may have aided in genome reorganization in this group of eubacteria prior to the formation of R. sphaeroides as gene

  9. Study of the Cupriavidus metallidurans CH34 resistance of selenite and selenate oxy-anions: accumulation, localisation and transformation of selenium; Etude de la resistance de Cupriavidus metallidurans CH34 aux oxyanions selenite et seleniate: accumulation, localisation et transformation du selenium

    Energy Technology Data Exchange (ETDEWEB)

    Avoscan, L

    2007-06-15

    Selenium is an essential trace element for the living organisms but it is very toxic at high concentration. Selenite and selenate oxides, soluble forms, highly toxic and bio-assimilable, are the most prevalent forms in the environment. Some soil micro-organisms play a dominant role and contribute to the natural cycle of selenium. Our study model, Cupriavidus (formerly Ralstonia) metallidurans CH34, a telluric bacterium characteristic of metal-contaminated biotopes, is known to resist selenite by reducing it into elemental selenium, an insoluble and less toxic form of selenium. In order to better understand the mechanisms of selenium reduction in the bacteria, three methods of speciation were combined (XAS (XANES and EXAFS), HPLC-ICP-MS and SDS-PAGEPIXE). They were completed by the direct quantification of selenium accumulated in the bacteria. Speciation analyses highlighted the existence of two mechanisms of reduction of selenium oxides in C. metallidurans CH34. Assimilation transforms selenite and selenate into organic selenium, identified as seleno-methionine and leads to its non-specific incorporation into bacterial proteins (presence of selenious proteins). Detoxication precipitates selenite in nano-particles of elemental selenium. This way of detoxication is not set up after an exposure to selenate although it is nevertheless possible to detect elemental selenium but in very small amount compared to the exposure of selenite. Seleno-diglutathion is detected in bacteria stressed by an exposure to selenate in medium limited in sulphate. Bacteria exposed to selenite accumulate 25 times more selenium than when they are exposed to selenate. The study of mutants resistant to selenite, which do not express the membrane protein DedA, showed that the accumulation of selenium after exposure to selenite is decreased compared with the wild strain meaning probable link between the transport of selenite and the DedA protein. Finally, selenate would use the sulphate permease

  10. Tellurite-, tellurate-, and selenite-based anaerobic respiration by strain CM-3 isolated from gold mine tailings.

    Science.gov (United States)

    Maltman, Chris; Piercey-Normore, Michele D; Yurkov, Vladimir

    2015-09-01

    The newly discovered strain CM-3, a Gram-negative, rod-shaped bacterium from gold mine tailings of the Central Mine in Nopiming Provincial Park, Canada, is capable of dissimilatory anaerobic reduction of tellurite, tellurate, and selenite. CM-3 possesses very high level resistance to these oxides, both aerobically and anaerobically. During aerobic growth, tellurite and tellurate resistance was up to 1500 and 1000 µg/ml, respectively. In the presence of selenite, growth occurred at the highest concentration tested, 7000 µg/ml. Under anaerobic conditions, resistance was decreased to 800 µg/ml for the Te oxides; however, much like under aerobic conditions, growth with selenite still took place at 7000 µg/ml. In the absence of oxygen, CM-3 couples oxide reduction to an increase in biomass. Following an initial drop in viable cells, due to switching from aerobic to anaerobic conditions, there was an increase in CFU/ml greater than one order of magnitude in the presence of tellurite (6.6 × 10(3)-8.6 × 10(4) CFU/ml), tellurate (4.6 × 10(3)-1.4 × 10(5) CFU/ml), and selenite (2.7 × 10(5)-5.6 × 10(6) CFU/ml). A control culture without metalloid oxides showed a steady decrease in CFU/ml with no recovery. ATP production was also increased in the presence of each oxide, further indicating anaerobic respiration. Partial 16S rRNA gene sequencing revealed a 99.0 % similarity of CM-3 to Pseudomonas reactans.

  11. Uptake of 75Se-selenite by brush border membrane vesicles from chick duodenum stimulated by vitamin D

    International Nuclear Information System (INIS)

    Mykkanen, H.M.; Wasserman, R.H.

    1989-01-01

    Brush border membrane vesicles were isolated from mucosal homogenates of duodena from normal, rachitic and vitamin D-treated rachitic chicks using a discontinuous sucrose gradient, and further purified by glycerol gradient centrifugation. In vitro uptake of 75Se-selenite by purified brush border membrane vesicles was studied using a rapid filtration technique. The time course of 75Se uptake was non-linear; rapid initial binding was followed by a gradual decrease in the rate of uptake until an equilibrium value was reached at 60-120 min. The initial binding at 36 s was not affected by selenite concentration in the incubation buffer, while the fractional rate of uptake between the 36 s and 2 min time periods was clearly lower with 1 mM Se than with 4-100 microM Se. 75Se uptake did not show any dependency on the external Na-gradient, nor could it be inhibited by other anions (arsenate, phosphate). Treatment of rachitic chicks either with cholecalciferol (500 Iu, 72 h) or with 1,25(OH)2-cholecalciferol (0.5 microgram given 16 h prior to isolation of the vesicles) significantly enhanced 75Se uptake. A threefold excess of mannitol in the outside buffer reduced 75Se uptake by vesicles from vitamin D-deficient and D-treated chicks 60% and 35% respectively, but had no effect on vesicles from vitamin D-treated chicks preloaded with 75Se. Neither saponin treatment nor excess cold selenite could release the label from the vesicles preloaded with 75Se. These data are compatible with the hypothesis that selenite easily crosses the brush border membrane into the intravesicular space and, once inside, is tightly bound by the membrane

  12. Identification of the upper exciton component of the B850 bacteriochlorophylls of the LH2 antenna complex, using a B800-free mutant of Rhodobacter sphaeroides.

    NARCIS (Netherlands)

    Koolhaas, M.H.C.; Frese, R.N.; Fowler, G.J.S.; Bibby, T.S.; Georgakopoulou, S.; van der Zwan, G.; Hunter, C.N.; van Grondelle, R.

    1998-01-01

    In this paper, we report the circular dichroism (CD) spectra of two types of LH2 -only mutants of Rhodobacter sphaeroides. In the first, only the wild type LH2 is present, while in the second, the B800 binding site of LH2 has been either destabilized or removed. For the first time, we have

  13. Two-dimensional crystals of LH2 light-harvesting complexes from Ectothiorhodospira sp. and Rhodobacter capsulatus investigated by electron microscopy.

    NARCIS (Netherlands)

    Oling, F.; Boekema, E.J.; Ortiz de Zarate, I.; Visschers, R.W.; van Grondelle, R.; Keegstra, W.; Brisson, A.; Picorel, R.

    1996-01-01

    Two-dimensional crystals of LH2 (B800-850) light-harvesting complexes from Ectothiorhodospira sp. and Rhodobacter capsulatus were obtained by reconstitution of purified protein into phospholipid vesicles and characterized by electron microscopy. The size of the crystals was up to several

  14. Exploration of the hydrogen producing potential of Rhodobacter capsulatus chemostat cultures: The application of deceleration-stat and gradient-stat methodology

    NARCIS (Netherlands)

    Hoekema, S.; Breukelen, van F.R.; Janssen, M.G.J.; Tramper, J.; Wijffels, R.H.

    2009-01-01

    In this work, the dependency of the volumetric hydrogen production rate of ammonium-limited Rhodobacter capsulatus chemostat cultures on their imposed biomass concentration and dilution rate was investigated. A deceleration-stat experiment was performed by lowering the dilution rate from 1.0 d-1 to

  15. Bacterial Survival under Extreme UV Radiation: A Comparative Proteomics Study of Rhodobacter sp., Isolated from High Altitude Wetlands in Chile

    Directory of Open Access Journals (Sweden)

    Vilma Pérez

    2017-06-01

    Full Text Available Salar de Huasco, defined as a polyextreme environment, is a high altitude saline wetland in the Chilean Altiplano (3800 m.a.s.l., permanently exposed to the highest solar radiation doses registered in the world. We present here the first comparative proteomics study of a photoheterotrophic bacterium, Rhodobacter sp., isolated from this remote and hostile habitat. We developed an innovative experimental approach using different sources of radiation (in situ sunlight and UVB lamps, cut-off filters (Mylar, Lee filters and a high-throughput, label-free quantitative proteomics method to comprehensively analyze the effect of seven spectral bands on protein regulation. A hierarchical cluster analysis of 40 common proteins revealed that all conditions containing the most damaging UVB radiation induced similar pattern of protein regulation compared with UVA and visible light spectral bands. Moreover, it appeared that the cellular adaptation of Rhodobacter sp. to osmotic stress encountered in the hypersaline environment from which it was originally isolated, might further a higher resistance to damaging UV radiation. Indeed, proteins involved in the synthesis and transport of key osmoprotectants, such as glycine betaine and inositol, were found in very high abundance under UV radiation compared to the dark control, suggesting the function of osmolytes as efficient reactive oxygen scavengers. Our study also revealed a RecA-independent response and a tightly regulated network of protein quality control involving proteases and chaperones to selectively degrade misfolded and/or damaged proteins.

  16. Attenuating the toxicity of cisplatin by using selenosulfate with reduced risk of selenium toxicity as compared with selenite

    International Nuclear Information System (INIS)

    Zhang Jinsong; Peng Dungeng; Lu Hongjuan; Liu Qingliang

    2008-01-01

    It has been reported that high doses of sodium selenite can reduce side effects of cisplatin (CDDP) without compromising its antitumor activity, thus substantially enhancing the cure rate in tumor-bearing mice. However, the toxicity of selenite at high doses should be a concern. The present study revealed that selenosulfate had much lower toxicity, but possessed equal efficacy in selenium (Se) utilization, as compared with selenite at similar doses when used for the intervention of CDDP. In addition, Se accumulation in whole blood and kidney of mice treated with selenosulfate was highly correlated with the survival rate of mice treated with CDDP (both r > 0.96 and both p < 0.05), suggesting that whole blood Se is a potential clinical biomarker to predict host tolerance to CDDP. In either Se-deficient or -sufficient mice bearing solid tumors of hepatoma 22 (H22), selenosulfate did not disturb the therapeutic effect of CDDP on tumors but effectively attenuated the toxicity of CDDP. Furthermore, in a highly malignant cancer model, with Se-sufficient mice bearing ascitic H22 cells, 8 or 10 mg/kg CDDP alone only achieved a null or 25% cure rate, whereas coadministration of selenosulfate with the above two doses of CDDP achieved cure rates of 87.5% or 75%. These results together argue for consideration of selenosulfate as an agent to enhance the therapeutic efficacy of CDDP

  17. Detoxification of selenite and mercury by reduction and mutual protection in the assimilation of both elements by Pseudomonas fluorescens

    International Nuclear Information System (INIS)

    Belzile, Nelson; Wu Gaojun; Chen, Yu-Wei; Appanna, Vasu D.

    2006-01-01

    A study on the assimilation and detoxification of selenium and mercury and on the interaction between these two elements was conducted on Pseudomonas fluorescens. P. fluorescens was able to convert separately both elements to their elemental forms, which are less toxic and biologically less available. To study the converting mechanism of selenite to elemental Se, cells were grown in the presence of various selenite concentrations and several parameters such as extracellular protein concentrations, pH, carbohydrate concentrations, isocitrate dehydrogenase (ICDH) and malic enzyme were monitored. Transmission electron microscopy (TEM) and various analytical methods were applied to confirm the interaction between selenium and cell. The former appeared as a red precipitate localized predominantly in the consumed culture medium. P. fluorescens also resisted to the toxic effect of mercury by converting Hg 2+ to the volatile and less toxic form Hg . Mercury reductase was likely responsible for the conversion of Hg 2+ to Hg . More importantly, the interaction between mercury and selenium was also studied. The presence of selenite significantly reduced the accumulation of mercury in P. fluorescens. It was also interesting to note that mercury appeared to behave as a protecting agent against selenium intoxication as the bioaccumulation of Se was also inhibited by this metal. The formation of Se-Hg complexes could explain this mutual protective effect. No precipitate of elemental Se could be detected when Hg was present in the cultures

  18. Simultaneous tracing of 76Se-selenite and 77Se-selenomethionine by absolute labeling and speciation

    International Nuclear Information System (INIS)

    Suzuki, Kazuo T.; Somekawa, Layla; Kurasaki, Kazuki; Suzuki, Noriyuki

    2006-01-01

    Nutritional selenocompounds are transformed into the assumed common intermediate selenide, which is utilized for the synthesis of selenoenzymes or transformed into methylated metabolites for excretion. Hence, selenocompound metabolites can be traced only with labeled selenium. Here we applied a new tracer method for the metallomics of biometals using simultaneous speciation of each metallome labeled with different homo-elemental isotopes to metabolism and availability of selenium. Rats were depleted of endogenous natural abundance selenium by feeding a single selenium stable isotope ( 82 Se-selenite) and then administered 76 Se-selenite and 77 Se-selenomethionine ( 77 Se-SeMet)simultaneously. Biological samples were subjected to quantification and speciation analysis by HPLC-ICPMS. Metabolites of the labeled 76 Se and 77 Se and interaction with endogenous selenium were traced and examined without interference from the corresponding endogenous natural abundance isotopes. Differences in the distribution and metabolism among organs and between the two nutritional selenocompounds were compared under exactly identical biological and analytical conditions: (1) selenite was distributed more efficiently than SeMet in organs and body fluids except the pancreas. (2) SeMet was taken up by organs in its intact form. (3) Selenium of SeMet origin was distributed selectively in the pancreas and mostly bound to a protein together with intact SeMet. (4) Selenosugars A and B but not trimethylselenonium (TMSe) were detected in the liver. (5) Selenosugar B and TMSe were detected in the kidneys

  19. Liberté et habitus chez Pierre Bourdieu.

    Directory of Open Access Journals (Sweden)

    Mathieu Hilgers

    2006-07-01

    Full Text Available La question de la libert é e st récurrente dans les théories de l’habitus. Bien qu'il en fasse un concept central, elle reste si peu thématisée chez Bourdieu que de nombreux critiques ont pu taxer son travail de déterministe. Pourtant, une lecture approfondie permet de dégager au cœur du modèle au moins trois principes qui le rendent incompatible avec le déterminisme : la production d’un nombre infini de comportements à partir d’un nombre limité de principes, la mutation permanente et les limites intensives et extensives de l’appréhension sociologique. L’identification de ses principes et l’analyse de leur portée sur la matrice conceptuelle permettent de mieux comprendre le statut de la liberté dans l’œuvre de Bourdieu. The question of freedom is recurrent in the theories of habitus. In the Bourdieu’s work, the freedom plays an essential role but not often explicit. This article tries to identify and to analyse the underlying principles of the freedom in this sociological approach.

  20. Intoxications aigues aux organophosphores chez la femme enceinte

    Science.gov (United States)

    Barhoumi, Mohamed Hafed; Bannour, Badra; Barhoumi, Tarek; Jouini, Rami; Marwene, Nadia; Fatnassi, Mohamed Ridha

    2016-01-01

    Les intoxications aiguës par les pesticides organophosphorés (OP) au cours de la grossesse sont des événements rares, peu décrites dans la littérature. A travers cette étude rétrospective, nous rapportons les résultats de sept cas d’ingestion suicidaire d’OP chez des femmes enceintes. Cette intoxication était le plus souvent grave. En effet, cinq des sept parturientes avaient un Glasgow initial des cas elle était défavorable pour le fœtus (mort fœtal in utéro). Deux mécanismes peuvent expliquer ces complications fœtales. Le premier est l’hypoxie fœtale associée ou non à un état de choc qui peuvent se traduire au niveau du RCF par une tachycardie ou des décélérations et aboutir ainsi à un décès in utero. Le deuxième mécanisme est le passage de ces pesticides à travers la barrière placentaire, ce qui pose un risque potentiel pour le fœtus par altération des systèmes enzymatiques des microsomes. PMID:28293343

  1. Sorption mechanisms of selenium species (selenite and selenate) on copper-based minerals; Mecanismes de sorption des especes du selenium (selenite et seleniate) sur des mineraux a base de cuivre

    Energy Technology Data Exchange (ETDEWEB)

    Devoy, J

    2001-09-01

    The sorption of radionuclides on the surface of minerals represents a process capable to delay the migration of the elements from a spent fuel deep repository towards the biosphere. In the framework of a deep underground repository, an engineered clay barrier has a high trapping capacity for cationic radio-elements, in particular because of the negative charge of clay surfaces. However, anionic radioelements like selenium species, would be only weakly retained by chemical processes. In order to optimize the trapping capacity of a clay barrier with respect to anionic species, prospective studies are carried out in order to find and evaluate some minerals with specific chemical trapping functions. Among radionuclides, the case of selenium has to be considered because its isotope {sup 79}Se is present in radioactive wastes and has a half life time of 6.5 10{sup 4} years. It is also judicious to find a mineral capable of trapping simultaneously several anionic radio-elements. Copper oxides and sulfides (Cu{sub 2}O, CuO, Cu{sub 2}S, CuS, CuFeS{sub 2} and Cu{sub 5}FeS{sub 4}) are good adsorbents with respect to selenium species (selenite and selenate). These minerals, with their selenium retention properties, could be used also for the decontamination of soils and waters or to process industrial effluents. The sorption mechanisms have been studied in details for copper oxides (Cu{sub 2}O and CuO) with respect to selenite and selenate. Chalcomenite precipitates in acid pH conditions when selenite is added to a Cu{sub 2}O and CuO suspension. Selenate, in contact with cuprite (Cu{sub 2}O) leads also to a selenium-based precipitate in acid pH environment. For higher pH values, selenite and selenate are adsorbed on copper oxides (Cu{sub 2}O and CuO) and lead to internal and external sphere complexes, respectively. In the case of a selenite/cuprite mixture in basic pH environment and at the equilibrium, a chemical reaction occurs between the oxidation product of cuprite, Cu

  2. Interaction of selenite with reduced Fe and/or S species: An XRD and XAS study.

    Science.gov (United States)

    Finck, Nicolas; Dardenne, Kathy

    2016-05-01

    In this study, we investigated the interaction between selenite and either Fe((II))aq or S((-II))aq in solution, and the results were used to investigate the interaction between Se((IV))aq and FeS in suspension. The reaction products were characterized by a combination of methods (SEM, XRD and XAS) and the reaction mechanisms were identified. In a first experiment, Se((IV))aq was reduced to Se((0)) by interaction with Fe((II))aq which was oxidized to Fe((III)), but the reaction was only partial. Subsequently, some Fe((III)) produced akaganeite (β-FeOOH) and the release of proton during that reaction decreased the pH. The pH decrease changed the Se speciation in solution which hindered further Se((IV)) reduction by Fe((II))aq. In a second experiment, Se((IV))aq was quantitatively reduced to Se((0)) by S((-II))aq and the reaction was fast. Two sulfide species were needed to reduce one Se((IV)), and the observed pH increase was due to a proton consumption. For both experiments, experimental results are consistent with expectations based on the oxidation reduction potential of the various species. Upon interaction with FeS, Se((IV))aq was reduced to Se((0)) and minute amounts of pyrite were detected, a consequence of partial mackinawite oxidation at surface sulfur sites. These results are of prime importance with respect to safe deep disposal of nuclear waste which contains the long-lived radionuclide (79)Se. This study shows that after release of (79)Se((IV)) upon nuclear waste matrix corrosion, selenite can be reduced in the near field to low soluble Se((0)) by interaction with Fe((II))aq and/or S((-II))aq species. Because the solubility of Se((0)) species is significantly lower than that of Se((IV)), selenium will become much less (bio)available and its migration out of deep HLW repositories may be drastically hindered. Copyright © 2016. Published by Elsevier B.V.

  3. Favreauite, a new selenite mineral from the El Dragon mine, Bolivia

    International Nuclear Information System (INIS)

    Mills, Stuart J.; Kampf, Anthony R.; Christy, Andrew G.; Housley, Robert M.; Chen, Yu-Sheng; Steele, Ian M.; Thorne, Brent

    2014-01-01

    Favreauite, ideally PbBiCu_6O_4(SeO_3)_4.H_2O, is a new secondary selenite mineral from the El Dragon mine, Antonio Quijarro Province, Potosi Department, Bolivia. The mineral occurs in vughs in a matrix of (Co, Cu)-rich penroseite, dolomite and goethite. Associated minerals are: ahlfeldite, allophane, calcite, chalcomenite, malachite, molybdomenite and an unnamed Al selenite. Favreauite forms tiny green square tbular crystals, flattened on {001}, up to 0.1 mm on edge and 0.01 mm thick, occurring in subparallel and divergent groups. The Mohs hardness of favreauite is estimated as ∼3; it has perfect cleavage on {001}, an irregular fracture and a vitreous lustre. The calculated density based on the empirical formula is 4.851 g cm"-"3. Favreauite is uniaxial (-), with mean refractive index estimated as 1.854 from the Gladstone-Dale relationship. It is pleochroic in shades of green, O 4σF_o] and 0.0356 for all 1432 unique reflections. Favreauite is a close structural relative of nabokoite, KCu_7Te"4"+O_4(SO_4)_5Cl, and atlasovite, KCu_6Fe"3"+BiO_4(SO_4)_5Cl. In all cases, oxygen-centred tetrahedra share edges to form corrugated [Cu_6MO_4] layers (M = Bi or Te) which can be derived from the framework structure of murdochite, Pb"4"+Cu"2"+_6O_8_-_x(Cl,Br)_2_x by selective deletion of atoms. In favreauite, additional OH and H_2O between the layers are weakly bound to Cu, giving it Jahn-Teller distorted 4 + 2 coordination. The Cu-Bi-O layer is braced by SeO_3 pyramids. The Bi"3"+ and interlayer Pb"2"+ form an approximately face-centred cubic array analogous to the Pb"4"+ sites in murdochite. Unlike Bi"3"+, Pb"2"+ is in a site with nonpolar anti 4 point symmetry, which suppresses the stereoactivity of its lone pair.

  4. Gradients socioéconomiques du risque cardiovasculaire chez les enfants et les adolescents canadiens

    Directory of Open Access Journals (Sweden)

    Y. Shi

    2016-01-01

    Full Text Available Introduction : Les maladies cardiovasculaires (MCV et leurs facteurs de risque présentent des gradients socioéconomiques clairs chez les adultes canadiens, mais présentent des ambiguïtés chez les enfants. L'objectif de cette étude est de vérifier l'existence ou non de gradients socioéconomiques dans les marqueurs physiologiques du risque de MCV chez les enfants et les adolescents canadiens. Méthodologie : À partir des données transversales combinées de l'Enquête canadienne sur les mesures de la santé 2007-2011, nous avons étudié, chez 2 149 enfants (6 à 11 ans et 2 073 adolescents (12 à 17 ans et selon le sexe, les marqueurs de risque cardiovasculaire suivants : excès de poids (y compris l'obésité, score de capacité aérobique (SCA, pression artérielle (PA, lipides sanguins (totaux, cholestérol LDL et HDL, triglycérides, métabolisme du glucose et protéine C réactive (CRP. Des analyses de régression logistique et de régression linéaire multidimensionnelles ont permis de dégager les tendances relatives au risque cardiovasculaire en fonction de la suffisance du revenu du ménage et du niveau de scolarité des parents, après ajustement en fonction de l'âge et de l'origine ethnique, et après stratification par groupe d'âge et par sexe. Résultats : La prévalence de l'obésité était sensiblement plus élevée chez les jeunes garçons que chez les jeunes filles (prévalence de 18,5 %, intervalle de confiance [IC] à 95 % : 15,6 à 21,5 contre 7,7 %, IC à 95 % : 5,2 à 10,3. Toutefois, des gradients socioéconomiques négatifs ont été observés en ce qui concerne le risque d'adiposité chez les jeunes filles et les adolescentes, et non chez les garçons. Parmi les enfants et les adolescents, les garçons étaient en meilleure condition physique que les filles (SCA moyen de 541, IC à 95 % : 534 à 546 contre 501, IC à 95 % : 498 à 505 chez les enfants; 522, IC à 95 % : 514 à 529 contre 460, IC à 95 % : 454

  5. Selenite -Se(4)- uptake mechanisms in the unicellular green alga Chlamydomonas reinhardtii: bioaccumulation and effects induced on growth and ultrastructure

    International Nuclear Information System (INIS)

    Morlon, H.

    2005-03-01

    Selenium is an essential element, but becomes very toxic at higher concentrations. It occurs in the environment at concentrations ranging from nM to μM and selenium pollution is a worldwide phenomenon. This works aims at improving the knowledge on the interactions between selenite - Se(IV) - and a freshwater phyto-planktonic organism: the unicellular green algae Chlamydomonas reinhardtii. The aim of the performed experiments were: i) to investigate selenite -Se(IV)- uptake mechanisms in C. reinhardtii, using Se 75 as a tracer in short term exposures ( -2 .nM -1 .h -1 . The uptake was proportional to ambient levels in a broad range of intermediate concentrations (from nM to μM). However, fluxes were higher at very low concentrations ( μM), suggesting that a high affinity but rapidly saturated transport mechanism could be used at low concentrations, in parallel with a low affinity mechanism that would only saturate at high concentrations (∼mM). The latter could involve transporters used by sulphate and nitrates, as suggested by the inhibition of selenite uptake by those element. Se(IV) speciation changes with pH did not induce significant effect on bioavailability. On the basis of the relationship between Se concentration and maximal cell density achieved, an EC50 of 80 μM ([64; 98]) was derived. No adaptation mechanism were observed as the same the same toxicity was quantified for Se-pre-exposed algae. Observations by TEM suggested chloroplasts as the first target of selenite cytotoxicity, with effects on the stroma, thylakoids and pyrenoids. At higher concentrations, we could observe an increase in the number and volume of starch grains. For the cell collected at 96 h, electron-dense granules were observed. Energy-dispersive X-ray microanalysis revealed that they contained selenium and were also rich in calcium and phosphorus. Finally, growth inhibition was highly correlated to the bioaccumulation of selenite. The latter was inhibited by increasing

  6. [Effect of glutathione and sodium selenite on the metabolism of arsenic in mice exposed to arsenic through drinking water].

    Science.gov (United States)

    Yu, Xiao-Yun; Zhong, Yuan; Niu, Yu-Hong; Qu, Chun-Qing; Li, Ge-Xin; Lü, Xiu-Qiang; Sun, Gui-Fan; Jin, Ya-Ping

    2008-09-01

    To explore the effect of glutathione (GSH) and sodium selenite on the metabolism of arsenic in the liver, kidney and blood of mice exposed to iAsIII through drinking water. The mice were randomly divided into control, arsenic, GSH and sodium selenite group, respectively. And each group had eight mice and the mice were exposed to 50 mg/L arsenite by drinking water for 4 weeks. Mice were intraperitoneally injected with GSH (600 mg/kg) and sodium selenite (1 mg/kg) for seven days from the beginning of the fourth week. At the end of the fourth week, liver, kidney and blood were sampled to assess the concentrations of inorganic arsenic (iAs), monomethylarsenic acid (MMA), dimethylarsenic acid (DMA) by hydride generation trapping by ultra-hypothermia coupled with atomic absorption spectrometry. The liver DMA (233.76 +/- 60.63 ng/g) concentration in GSH group was significantly higher than the arsenic group (218.36 +/- 42.71 ng/g). The concentration of DMA (88.52 +/- 30.86 ng/g) and total arsenic (TAs) (162.32 +/- 49.45 ng/g) in blood of GSH group was significantly higher than those [(45.32 +/- 12.19 ng/g), (108.51 +/- 18.00 ng/g), respectively] of arsenic groups(q values were 3.06, 6.40, 10.72 respectively, P < 0.05). The primary methylated index (PMI) (0.65 +/- 0.050) and secondary methylated index (SMI) (0.55 +/- 0.050) in liver sample of GSH group were significantly higher than those (0.58 +/- 0.056, 0.44 +/- 0. 093) in arsenic group. In blood samples, the PMI (0.85 +/- 0.066) in GSH group was significantly higher than that (0.54 +/- 0.113) in arsenic group (q values were 3.75, 5.26, 4.21 respectively, P < 0.05). However, no significant difference was identified between sodium selenite and arsenic groups in liver, kidney or blood samples. And no significant difference was detected in kidney samples among all arsenic exposing groups. Exogenous GSH could promote the methylated metabolism of iAsIII, but sodium selenite showed no significant effects.

  7. Selenite resistant rhizobacteria stimulate SeO(3) (2-) phytoextraction by Brassica juncea in bioaugmented water-filtering artificial beds.

    Science.gov (United States)

    Lampis, Silvia; Ferrari, Anita; Cunha-Queda, A Cristina F; Alvarenga, Paula; Di Gregorio, Simona; Vallini, Giovanni

    2009-09-01

    Selenium is a trace metalloid of global environmental concern. The boundary among its essentiality, deficiency, and toxicity is narrow and mainly depends on the chemical forms and concentrations in which this element occurs. Different plant species-including Brassica juncea-have been shown to play a significant role in Se removal from soil as well as water bodies. Furthermore, the interactions between such plants, showing natural capabilities of metal uptake and their rhizospheric microbial communities, might be exploited to increase both Se scavenging and vegetable biomass production in order to improve the whole phytoextraction efficiency. The aim of the present study was to evaluate the capability of selenite removal of B. juncea grown in hydroponic conditions on artificially spiked effluents. To optimize phytoextraction efficiency, interactions between B. juncea and rhizobacteria were designedly elicited. Firstly, B. juncea was grown on water-filtering agriperlite beds in the presence of three different selenite concentrations, namely, 0.2, 1.0, and 2.0 mM. Plant growth was measured after 3 and 6 weeks of incubation in order to establish the selenite concentration at which the best plant biomass production could be obtained. Afterwards, water-filtering agriperlite beds were inoculated either with a selenium-acclimated microbial community deriving from the rhizosphere of B. juncea grown, erstwhile, in a selenite-amended soil or with axenic cultures of two bacterial strains, vicelike Bacillus mycoides SeITE01 and Stenotrophomonas maltophilia SeITE02, previously isolated and described for their high resistance to selenite. These latter were seeded separately or as a dual consortium. Selenite was amended at a final concentration of 1.0 mM. Total Se content in plant tissues (both shoots and roots), plant biomass production, and persistence of bioaugmented microbial inocula during the experimental time were monitored. Moreover, parameters such as bioconcentration

  8. Biochemical analysis and the preliminary crystallographic characterization of D-tagatose 3-epimerase from Rhodobacter sphaeroides.

    Science.gov (United States)

    Qi, Zhengliang; Zhu, Zhangliang; Wang, Jian-Wen; Li, Songtao; Guo, Qianqian; Xu, Panpan; Lu, Fuping; Qin, Hui-Min

    2017-11-09

    D-Tagatose 3-epimerase epimerizes D-fructose to yield D-psicose, which is a rare sugar that exists in small quantities in nature and is difficult to synthesize chemically. We aim to explore potential industrial biocatalysts for commercial-scale manufacture of this rare sugar. A D-tagatose 3-epimerase from Rhodobacter sphaeroides (RsDTE) has recently been identified as a D-tagatose 3-epimerase that can epimerize D-fructose to yield D-psicose with a high conversion rate. The purified RsDTE by Ni-affinity chromatography, ionic exchange chromatography and gel filtration forms a tetramer in solution. The maximal activity was in Tris-HCl buffer pH 8.5, and the optimal temperature was at 35 °C. The product, D-psicose, was confirmed using HPLC and NMR. Crystals of RsDTE were obtained using crystal kits and further refined under crystallization conditions such as 10% PEG 8000,0.1 M HEPES pH 7.5, and 8% ethylene glycol at 20 °C using the sitting-drop vapor diffusion method. The RsDTE homology model showed that it possessed the characteristic TIM-barrel fold. Four residues, Glu156, Asp189, Gln215 and Glu250, forms a hydrogen bond network with the active Mn(II) for the hydride transfer reaction. These residues may constitute the catalytic tetrad of RsDTE. The residues around O1, O2 and O3 of the substrates were conserved. However, the binding-site residues are different at O4, O5 and O6. Arg118 formed the unique hydrogen bond with O4 of D-fructose which indicates RsDTE's preference of D-fructose more than any other family enzymes. RsDTE possesses a different metal-binding site. Arg118, forming unique hydrogen bond with O4 of D-fructose, regulates the substrate recognition. The research on D-tagatose 3-epimerase or D-psicose 3-epimerase enzymes attracts enormous commercial interest and would be widely used for rare sugar production in the future.

  9. Grain dust-induced lung inflammation is reduced by Rhodobacter sphaeroides diphosphoryl lipid A.

    Science.gov (United States)

    Jagielo, P J; Quinn, T J; Qureshi, N; Schwartz, D A

    1998-01-01

    To further determine the importance of endotoxin in grain dust-induced inflammation of the lower respiratory tract, we evaluated the efficacy of pentaacylated diphosphoryl lipid A derived from the lipopolysaccharide of Rhodobacter sphaeroides (RsDPLA) as a partial agonist of grain dust-induced airway inflammation. RsDPLA is a relatively inactive compound compared with lipid A derived from Escherichia coli (LPS) and has been demonstrated to act as a partial agonist of LPS-induced inflammation. To assess the potential stimulatory effect of RsDPLA in relation to LPS, we incubated THP-1 cells with RsDPLA (0.001-100 micrograms/ml), LPS (0.02 microgram endotoxin activity/ml), or corn dust extract (CDE; 0.02 microgram endotoxin activity/ml). Incubation with RsDPLA revealed a tumor necrosis factor (TNF)-alpha stimulatory effect at 100 micrograms/ml. In contrast, incubation with LPS or CDE resulted in TNF-alpha release at 0.02 microgram/ml. Pretreatment of THP-1 cells with varying concentrations of RsDPLA before incubation with LPS or CDE (0.02 microgram endotoxin activity/ml) resulted in a dose-dependent reduction in the LPS- or CDE-induced release of TNF-alpha with concentrations of RsDPLA of up to 10 micrograms/ml but not at 100 micrograms/ml. To further understand the role of endotoxin in grain dust-induced airway inflammation, we utilized the unique LPS inhibitory property of RsDPLA to determine the inflammatory response to inhaled CDE in mice in the presence of RsDPLA. Ten micrograms of RsDPLA intratracheally did not cause a significant inflammatory response compared with intratracheal saline. However, pretreatment of mice with 10 micrograms of RsDPLA intratracheally before exposure to CDE (5.4 and 0.2 micrograms/m3) or LPS (7.2 and 0.28 micrograms/m3) resulted in significant reductions in the lung lavage concentrations of total cells, neutrophils, and specific proinflammatory cytokines compared with mice pretreated with sterile saline. These results confirm the LPS

  10. Multi-PAS domain-mediated protein oligomerization of PpsR from Rhodobacter sphaeroides

    International Nuclear Information System (INIS)

    Heintz, Udo; Meinhart, Anton; Winkler, Andreas

    2014-01-01

    Crystal structures of two truncated variants of the transcription factor PpsR from R. sphaeroides are presented that enabled the phasing of a triple PAS domain construct. Together, these structures reveal the importance of α-helical PAS extensions for multi-PAS domain-mediated protein oligomerization and function. Per–ARNT–Sim (PAS) domains are essential modules of many multi-domain signalling proteins that mediate protein interaction and/or sense environmental stimuli. Frequently, multiple PAS domains are present within single polypeptide chains, where their interplay is required for protein function. Although many isolated PAS domain structures have been reported over the last decades, only a few structures of multi-PAS proteins are known. Therefore, the molecular mechanism of multi-PAS domain-mediated protein oligomerization and function is poorly understood. The transcription factor PpsR from Rhodobacter sphaeroides is such a multi-PAS domain protein that, in addition to its three PAS domains, contains a glutamine-rich linker and a C-terminal helix–turn–helix DNA-binding motif. Here, crystal structures of two N-terminally and C-terminally truncated PpsR variants that comprise a single (PpsR Q-PAS1 ) and two (PpsR N-Q-PAS1 ) PAS domains, respectively, are presented and the multi-step strategy required for the phasing of a triple PAS domain construct (PpsR ΔHTH ) is illustrated. While parts of the biologically relevant dimerization interface can already be observed in the two shorter constructs, the PpsR ΔHTH structure reveals how three PAS domains enable the formation of multiple oligomeric states (dimer, tetramer and octamer), highlighting that not only the PAS cores but also their α-helical extensions are essential for protein oligomerization. The results demonstrate that the long helical glutamine-rich linker of PpsR results from a direct fusion of the N-cap of the PAS1 domain with the C-terminal extension of the N-domain that plays an important

  11. Assembly of functional photosystem complexes in Rhodobacter sphaeroides incorporating carotenoids from the spirilloxanthin pathway

    Science.gov (United States)

    Chi, Shuang C.; Mothersole, David J.; Dilbeck, Preston; Niedzwiedzki, Dariusz M.; Zhang, Hao; Qian, Pu; Vasilev, Cvetelin; Grayson, Katie J.; Jackson, Philip J.; Martin, Elizabeth C.; Li, Ying; Holten, Dewey; Neil Hunter, C.

    2015-01-01

    Carotenoids protect the photosynthetic apparatus against harmful radicals arising from the presence of both light and oxygen. They also act as accessory pigments for harvesting solar energy, and are required for stable assembly of many light-harvesting complexes. In the phototrophic bacterium Rhodobacter (Rba.) sphaeroides phytoene desaturase (CrtI) catalyses three sequential desaturations of the colourless carotenoid phytoene, extending the number of conjugated carbon–carbon double bonds, N, from three to nine and producing the yellow carotenoid neurosporene; subsequent modifications produce the yellow/red carotenoids spheroidene/spheroidenone (N = 10/11). Genomic crtI replacements were used to swap the native three-step Rba. sphaeroides CrtI for the four-step Pantoea agglomerans enzyme, which re-routed carotenoid biosynthesis and culminated in the production of 2,2′-diketo-spirilloxanthin under semi-aerobic conditions. The new carotenoid pathway was elucidated using a combination of HPLC and mass spectrometry. Premature termination of this new pathway by inactivating crtC or crtD produced strains with lycopene or rhodopin as major carotenoids. All of the spirilloxanthin series carotenoids are accepted by the assembly pathways for LH2 and RC–LH1–PufX complexes. The efficiency of carotenoid-to-bacteriochlorophyll energy transfer for 2,2′-diketo-spirilloxanthin (15 conjugated C 000000000000 000000000000 000000000000 111111111111 000000000000 111111111111 000000000000 000000000000 000000000000 C bonds; N = 15) in LH2 complexes is low, at 35%. High energy transfer efficiencies were obtained for neurosporene (N = 9; 94%), spheroidene (N = 10; 96%) and spheroidenone (N = 11; 95%), whereas intermediate values were measured for lycopene (N = 11; 64%), rhodopin (N = 11; 62%) and spirilloxanthin (N = 13; 39%). The variety and stability of these novel Rba. sphaeroides antenna complexes make them useful experimental models for investigating the

  12. The Protective Effect of Sesamol in the Selenite-induced Experimental Cataract Model

    Directory of Open Access Journals (Sweden)

    Burak Turgut

    2017-12-01

    Full Text Available Objectives: To investigate the potential protective effects of sesamol in an experimental cataract model. Materials and Methods: Twenty-one Spraque Dawley rat pups were randomly assigned into three groups, seven rats in each. All the rats except for those in the control group were injected subcutaneously with a single dose of sodium selenite on postpartum day 9. On days 10-14, rats in the sham group were intraperitoneally administered 50 mg/kg/day saline solution, while rats in the sesamol group were given 50 mg/kg/day sesamol by the same route. Following cataract grading, the lenses and capsules were extracted and the mean levels of reduced glutathione (GSH, malondialdehyde (MDA, total antioxidant status (TAS and total oxidant status (TOS in lens supernatants were biochemically analyzed. Results: The control group did not show any development of cataract. It was found that the mean cataract grade in the sesamol group was significantly lower than that of the sham group (p<0.05. The mean GSH level and TAS in the sesamol group were significantly higher than those of the sham group while the mean TOS and MDA level in the sesamol group were significantly lower than those of the sham group (p<0.05. Conclusion: Our study shows that sesamol reduces TOS and MDA level and increases TAS and GSH level in the lens and inhibits cataract formation.

  13. Application of Sodium Selenite in the Prevention and Treatment of Cancers

    Directory of Open Access Journals (Sweden)

    Marek Kieliszek

    2017-10-01

    Full Text Available Selenium is an essential trace element that occurs in nature, in both inorganic and organic forms. This element participates in numerous biochemical processes, including antioxidant potential, but the mechanism of its anti-cancer action is still not well known. It should be noted that the anti-cancer properties of selenium depends on its chemical form, therapeutic doses, and the tumor type. Higher nutritional doses of selenium can stimulate human immune system. There are several hypotheses concerning the anticancer activity of selenium, including oxidation of sulfhydryl groups in proteins causing their conformational alterations. Conformational changes in proteins have the ability to weaken the activity of enzymes involved in the metabolism of cancer cells. In case of human fibrinogen sodium selenite, but not selenate, it inhibits protein disulfide exchange reactions, thus preventing formation of a hydrophobic polymer termed parafibrin, circulatory accumulation, of which is associated with numerous degenerative diseases. Parafibrin can specifically form a protein coat around tumor cells that is completely resistant to degradation induced with lymphocyte protease. In this way, cancer cells become protected against destruction by the organism’s immune system. Other possible mechanisms of anticancer action of selenium are being still investigated.

  14. Switching to instant black coffee modulates sodium selenite-induced cataract in rats

    Directory of Open Access Journals (Sweden)

    El Okda, E. A.

    2016-04-01

    Full Text Available The influence of daily consumption of some common beverages on the development of cataract in rats was investigated. Total phenol content was determined in the beverages and an oral standardized dose of total phenols from each beverage was given to the treated rats. Weaned male albino rats were used and divided into five groups (n=7. Rats were fed Ain 93G and administered the standardized dose of instant coffee, black tea and hibiscus beverages for 30 days. On day 14 all rats were injected with a single dose of sodium selenite (NaSeO bodyweight, except the control groups NC (negative control, did not receive NaSeO and PC (positive control, was already injected on day 1 of the study. The rats were continued on Ain 93G and the standardized dose for another 16 days. Positive control rats were used. Total phenols were 210, 40, and 44 mg/g dry weight gallic acid equivalent in black coffee, black tea, and hibiscus, respectively. Decreased levels (statistically significant P<0.05 of malondialdehyde, total nitric oxide, Ca-Ae, tumor necrosis factor-α, interleukin-1β, superoxide dismutase, and conversely, increased levels (statistically significant P<0.05 of total protein, reduced glutathione, catalase were found in the lenses of the coffee group compared to PC. There are co-phenol substances in the instant black coffee that promoted coffee to be the most effective beverage.

  15. Synthesis, structure, and photoluminescence properties of an organically-templated uranyl selenite

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Dong-Sheng; Kuang, Han-Mao; Chen, Wen-Tong; Luo, Qiu-Yan; Sui, Yan [Institute of Applied Chemistry, School of Chemistry and Chemical Engineering, Jinggangshan University, Ji' an, Jiangxi 343009 (China)

    2015-09-15

    The organically-templated uranyl selenite, (H{sub 2}en)[(UO{sub 2})(SeO{sub 3})(HSeO{sub 3})](NO{sub 3}).0.5H{sub 2}O (1) (en = 1,2-ethylenediamine) was synthesized and characterized by elemental analyses, IR spectroscopy, TG, and single-crystal X-ray diffraction. Compound 1 crystallizes in the orthorhombic system, space group Pbca, with a = 13.170(3) Aa, b = 11.055(2) Aa, c = 18.009(4) Aa, V = 2621.8(9) Aa{sup 3}, M = 1316.19, Z = 4, D{sub cal} = 3.334 g.cm{sup -3}, μ(Mo-K{sub α}) = 17.998 mm{sup -1}, GOF = 1.059, R{sub 1} = 0.0263, wR{sub 2} = 0.0532 [I>2σ(I)]. The X-ray diffraction analysis reveals that compound 1 has a three-dimensional (3D) supramolecular structure. It contains negatively charged [UO{sub 2}(HSeO{sub 3})(SeO{sub 3})]{sup -} inorganic anion layers and is balanced by [H{sub 2}en]{sup 2+} cations and NO{sub 3}{sup -} anions located in the interlayers. Furthermore, the photoluminescence properties of 1 were investigated. (Copyright copyright 2015 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  16. Tocopherol and selenite modulate the transplacental effects induced by sodium arsenite in hamsters.

    Science.gov (United States)

    Sampayo-Reyes, Adriana; Taméz-Guerra, Reyes S; Bermúdez de León, Mario; Vargas-Villarreal, Javier; Lozano-Garza, Héctor Gerardo; Rodríguez-Padilla, Cristina; Cortés, Constanza; Marcos, Ricard; Hernández, Alba

    2017-12-01

    Human studies suggest that in utero exposure to arsenic results in adverse pregnancy outcomes. The use of dietary supplements, such as sodium selenite (SS) or α-tocopherol succinate (α-TOS), is a reasonable approach to ameliorate such health effects. Sodium arsenite at 100ppm was administered via drinking water to female hamsters from gestational days 1 or 8 to the time of delivery. Viable fetuses, fetal resorptions and non-viable fetuses were recorded during and after pregnancy and total arsenic and its metabolites were characterized in pregnant animals, placentas and fetuses. Arsenic was found to accumulate in the placenta and fetus, increasing fetal mortality, non-viable fetuses and resorptions. Co-administration of SS and α-TOS significantly reduced the observed teratogenic effects. SS influenced arsenic biotransformation by reducing the MMA/InAs index and increasing the DMA/MMA, whereas α-TOS more likely exerts its protective effect through its potent antioxidant activity. Copyright © 2017 Elsevier Inc. All rights reserved.

  17. Abiotic pyrite reactivity versus nitrate, selenate and selenite using chemical and electrochemical methods

    International Nuclear Information System (INIS)

    Ignatiadis, I.; Betelu, S.; Gaucher, E.; Tournassat, C.; Chainet, F.

    2010-01-01

    Document available in extended abstract form only. This work is part of ReCosy European project (www.recosy.eu), whose main objectives are the sound understanding of redox phenomena controlling the long-term release/retention of radionuclides in nuclear waste disposal and providing tools to apply the results to performance assessment/safety case. Redox is one of the main factor affecting speciation and mobility of redox-sensitive radionuclides. Thus, it is of a great importance to investigate the redox reactivity of the host radioactive waste formations, particularly when exposed to redox perturbations. Callovo-Oxfordian formation (COx), a clay rock known as an anoxic and reducing system, was selected in France as the most suitable location to store nuclear waste. Iron (II) sulfide, mostly constituted of pyrite (FeS 2 ), iron (II) carbonate, iron(II) bearing clays and organic matter are considered to account almost entirely for the total reducing capacity of the rock. We report here the redox reactivity of pyrite upon exposure to nitrate (N(V)), selenate (Se(VI)) and selenite (Se(IV)) that possibly occur in the nuclear storage. Both, chemical and electrochemical kinetic approaches were simultaneously conducted such as to (i) determine the kinetics parameters of the reactions and (ii) understand the kinetic mechanisms. In order to reach similar conditions that are encountered in the storage system, all experiments were realised in NaCl 0.1 M, near neutral pH solutions, and an abiotic glove box (O 2 less than 10 -8 M). Chemical approach has consisted to set in contact pyrite in grains with solutions containing respectively nitrate, selenate and selenite. Reactants and products chemical analyses, conducted at different contact times, allowed us to assess the kinetics of oxidant reduction. Electrochemical approach has consisted in the continuous or semi-continuous analysis of large surface pyrite electrodes immersed in solutions with or without oxidant (nitrate

  18. Investigating different mechanisms for biogenic selenite transformations: Geobacter sulfurreducens, Shewanella oneidensis and Veillonella atypica

    Science.gov (United States)

    Pearce, C.I.; Pattrick, R.A.D.; Law, N.; Charnock, J.M.; Coker, V.S.; Fellowes, J.W.; Oremland, R.S.; Lloyd, J.R.

    2009-01-01

    The metal-reducing bacteria Geobacter sulfurreducens, Shewanella oneidensis and Veillonella atypica, use different mechanisms to transform toxic, bioavailable sodium selenite to less toxic, non-mobile elemental selenium and then to selenide in anaerobic environments, offering the potential for in situ and ex situ bioremediation of contaminated soils, sediments, industrial effluents, and agricultural drainage waters. The products of these reductive transformations depend on both the organism involved and the reduction conditions employed, in terms of electron donor and exogenous extracellular redox mediator. The intermediary phase involves the precipitation of elemental selenium nanospheres and the potential role of proteins in the formation of these structures is discussed. The bionanomineral phases produced during these transformations, including both elemental selenium nanospheres and metal selenide nanoparticles, have catalytic, semiconducting and light-emitting properties, which may have unique applications in the realm of nanophotonics. This research offers the potential to combine remediation of contaminants with the development of environmentally friendly manufacturing pathways for novel bionanominerals. ?? 2009 Taylor & Francis.

  19. Synthesis, vibrational and quantum chemical investigations of hydrogen bonded complex betaine dihydrogen selenite

    Science.gov (United States)

    Arjunan, V.; Marchewka, Mariusz K.; Kalaivani, M.

    2012-10-01

    The molecular complex of betaine with selenious acid namely, betaine dihydrogen selenite (C5H13NO5Se, BDHSe) was synthesised by the reaction of betaine and SeO2 in a 1:1:1 solution of isopropanol, methanol and water. Crystals were grown from this solution by cooling to 253 K for few days. The complex was formed without accompanying proton transfer from selenious acid molecule to betaine. The complete vibrational assignments and analysis of BDHSe have been performed by FTIR, FT-Raman and far-infrared spectral studies. More support on the experimental findings was added from the quantum chemical studies performed with DFT (B3LYP) method using 6-311++G∗∗, 6-31G∗∗, cc-pVDZ and 3-21G basis sets. The structural parameters, energies, thermodynamic parameters and the NBO charges of BDHSe were determined by the DFT method. The 1H and 13C isotropic chemical shifts (δ ppm) of BDHSe with respect to TMS were also calculated using the gauge independent atomic orbital (GIAO) method and compared with the experimental data. SHG experiment was carried out using Kurtz-Perry powder technique. The efficiency of second harmonic generation for BDHSe was estimated relatively to KDP: deff = 0.97 deff (KDP).

  20. Radioprotective effect of sodium selenite on bone repair in the tibia of ovariectomized rats

    Energy Technology Data Exchange (ETDEWEB)

    Freitas, Deborah Queiroz de; Neves, Ellen Gaby; Boscolo, Frab Norberto; Almeida, Solange Maria de [University of Campinas (UNICAMP), Piracicaba, SP (Brazil). Piracicaba Dental School. Department of Oral Diagnosis. Oral Radiology Area; Ramos-Perez, Flavia Maria de Moraes [Federal University of Pernambuco, Recife, PE (Brazil). Department of Clinical and Preventive Dentistry; Marques, Marcelo Rocha [University of Campinas (UNICAMP), Piracicaba, SP (Brazil). Piracicaba Dental School. Division of Histology. Department of Morphology

    2012-07-01

    This study evaluated protection by selenium (Se) in the bone repair process in ovariectomized rats after irradiation. For such purpose, 80 ovariectomized female Wistar rats were randomly divided into 4 experimental groups: ovariectomized (Ov), Ov/Se, Ov/irradiated (Irr) and Ov/ Se/Irr. A bone defect was created on the tibia of all animals 40 days after ovariectomy. Two days after surgery, only the Ov/Se and Ov/Se/Irr rats received 0.8 mg Se/kg. Three days after surgery, only the Ov/Irr and Ov/Se/Irr rats received 10 Gy of x-rays on the lower limb region. The animals were euthanized at 7, 14, 21 and 28 days after surgery to assess the repair process, which was evaluated by analysis of trabecular bone number (Masson Trichrome) and birefringence analysis (Picrosirius). It was possible to observe a delay in the bone repair process in the ovariectomized/irradiated group and similarity between the ovariectomized, Ov/Se and Ov/Se/Irr groups. In conclusion, sodium selenite exerted a radioprotective effect in the bone repair of tibia of ovariectomized rats without toxicity. (author)

  1. Effects of lead nitrate and sodium selenite on DNA damage and oxidative stress in diabetic and non-diabetic rat erythrocytes and leucocytes.

    Science.gov (United States)

    Baş, Hatice; Kalender, Yusuf; Pandir, Dilek; Kalender, Suna

    2015-05-01

    The adverse effects of lead nitrate (LN) and the preventive role of sodium selenite were investigated in diabetic and non-diabetic rat blood by measuring trolox equivalent antioxidant capacity (TEAC), ferric reducing antioxidant power (FRAP), malondialdehyde (MDA) levels and activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) also by evaluating DNA damage with comet assay. LN increased the levels of MDA, tail DNA%, mean tail length and tail moment, decreased the enzymes activities, FRAP and TEAC values. In sodium selenite+LN group, we observed the protective effect of sodium selenite on examining parameters. Diabetes caused alterations on these parameters, too. We found that sodium selenite did not protect against diabetes caused damages. As a result, LN caused toxic effects on blood cells and sodium selenite alleviated this toxicity but it did not show preventive effect against diabetes. Also, LN caused more harmfull effects in diabetic groups than non-diabetic groups. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Mechanism(s of Toxic Action of Zn2+ and Selenite: A Study on AS-30D Hepatoma Cells and Isolated Mitochondria

    Directory of Open Access Journals (Sweden)

    Elena A. Belyaeva

    2011-01-01

    Full Text Available Mitochondria of AS-30D rat ascites hepatoma cells are found to be the main target for Zn2+ and sodium selenite (Na2SeO3. High [mu]M concentrations of Zn2+ or selenite were strongly cytotoxic, killing the AS-30D cells by both apoptotic and necrotic ways. Both Zn2+ and selenite produced strong changes in intracellular generation of reactive oxygen species (ROS and the mitochondrial dysfunction via the mitochondrial electron transport chain (mtETC disturbance, the membrane potential dissipation, and the mitochondrial permeability transition pore opening. The significant distinctions in toxic action of Zn2+ and selenite on AS-30D cells were found. Selenite induced a much higher intracellular ROS level (the early event compared to Zn2+ but a lower membrane potential loss and a lower decrease of the uncoupled respiration rate of the cells, whereas the mtETC disturbance was the early and critical event in the mechanism of Zn2+ cytotoxicity. Sequences of events manifested in the mitochondrial dysfunction produced by the metal/metalloid under test are compared with those obtained earlier for Cd2+, Hg2+, and Cu2+ on the same model system.

  3. Bases chimiosensorielles du comportement alimentaire chez les poissons

    Directory of Open Access Journals (Sweden)

    SAGLIO Ph.

    1981-07-01

    Full Text Available Le comportement alimentaire, indispensable à la survie de l'individu et donc de l'espèce, occupe à ce titre une position de première importance dans la hiérarchie des comportements fondamentaux qui tous en dépendent très étroitement. Chez les poissons, cette prééminence se trouve illustrée par l'extrême diversité des supports sensoriels impliqués et des expressions comportementales qui leur sont liées. A la suite d'un certain nombre de mises en évidence neurophysiologiques et éthologiques de l'importance du sens chimique (olfaction, gustation dans le comportement alimentaire des poissons, de très importants secteurs d'études électrophysiologiques et d'analyses physico-chimiques visant à en déterminer la nature exacte (en termes de substances actives se sont développés ces vingt dernières années. De tous ces travaux dont les plus avancés sont présentés ici, il ressort que les acides aminés de série L plus ou moins associés à d'autres composés de poids moléculaires < 1000 constituent des composés chimiques jouant un rôle déterminant dans le comportement alimentaire de nombreuses espèces de poissons carnivores.

  4. Mise en évidence d'une variation intra spécifique chez Botrytis ...

    African Journals Online (AJOL)

    SARAH

    25 avr. 2013 ... 2 Présidence de l'Université Ibn Tofaïl, Kenitra, Maroc. Auteur correspondant .... ambiante et sous lumière continue afin de favoriser davantage la .... formation de sclérotes sur les disques foliaires de tomate est observée chez ...

  5. Dépistage sérologique de la maladie coeliaque chez des patients ...

    African Journals Online (AJOL)

    transglutaminase tissulaire (AtTG) et anti-gliadines (AAG) chez les patients diabétiques de type 1 dans le but de recommander une éventuelle biopsie jéjunale et d'instaurer un régime sans gluten précocement avant l'installation des signes ...

  6. La dialyse péritonéale chez les patients de moins de vingt ans ...

    African Journals Online (AJOL)

    La dialyse péritonéale chez les patients de moins de vingt ans: expérience d'un centre hospitalier universitaire marocain. Intissar Haddiya, Hakima Rhou, Fatima Ezaitouni, Naima Ouzeddoun, Rabia Bayahia, Loubna Benamar ...

  7. Les accidents de la vie courante chez l'enfant à Dakar: à propos de ...

    African Journals Online (AJOL)

    Les accidents de la vie courante chez l'enfant à Dakar: à propos de 201 cas. Azhar Salim Mohamed, Aloïse Sagna, Mbaye Fall, Ndeye Aby Ndoye, Papa Alassane Mbaye, Aimé Lakh Fall, Alou Diaby, Oumar Ndour, Gabriel Ngom ...

  8. Les troubles gonadiques chez les hémodialysés chroniques à l ...

    African Journals Online (AJOL)

    étude montre une forte prévalence des manifestations cliniques des troubles gonadiques chez les patients en hémodialyse chronique. Aussi elles doivent être recherchées afin de mieux les prendre en charge, car ces troubles sont vécus par ...

  9. S'attaquer à la marginalisation, à la criminalité et à la violence chez ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    S'attaquer à la marginalisation, à la criminalité et à la violence chez les jeunes - le rôle du capital social communautaire. Il est maintenant reconnu que les adolescents ont besoin d'un capital social positif (réseaux sociaux, relations interpersonnelles) pour devenir des adultes productifs et socialement responsables.

  10. Evolution des paramètres biochimiques chez les chevaux de sport ...

    African Journals Online (AJOL)

    Evolution des paramètres biochimiques chez les chevaux de sport pendant un test d'effort. ... English Title: Evolution of biochemical parameters in sport horses subjected to a stress test. English Abstract. The study aimed ... The evaluation of the fitness of these racehorses is of great use in assessing the physical conditions.

  11. Transient absorption study of two-photon excitation mechanism in the LH2 complex from purple bacterium Rhodobacter sphaeroides.

    Science.gov (United States)

    Stepanenko, Ilya; Kompanetz, Viktor; Makhneva, Zoya; Chekalin, Sergey; Moskalenko, Andrei; Razjivin, Andrei

    2012-03-08

    The mechanism of two-photon excitation of a peripheral light-harvesting complex LH2 (B800-850) from purple bacterium Rhodobacter sphaeroides was explained on the basis of femtosecond transient absorption data. Fast bleaching of the B850 absorption band was measured under two-photon excitation by 1350 nm femtosecond pulses, showing fast subpicosecond arrival of excitation energy to B850 circular aggregates. Any spectral changes connected with the B800 absorption band of B800-BChl molecules were absent. A similar picture was observed under one-photon excitation of the LH2 complex by 675 nm femtosecond pulses. We believe these effects may be attributed to direct excitation of high-energy excitonic states of a B850 circular aggregate or its vibrational manifold in accordance with the model of Abe [Chem. Phys. 2001, 264, 355-363].

  12. Characterization of D-tagatose-3-epimerase from Rhodobacter sphaeroides that converts D-fructose into D-psicose.

    Science.gov (United States)

    Zhang, Longtao; Mu, Wanmeng; Jiang, Bo; Zhang, Tao

    2009-06-01

    A non-characterized gene, previously proposed as the D-tagatose-3-epimerase gene from Rhodobacter sphaeroides, was cloned and expressed in Escherichia coli. Its molecular mass was estimated to be 64 kDa with two identical subunits. The enzyme specificity was highest with D-fructose and decreased for other substrates in the order: D-tagatose, D-psicose, D-ribulose, D-xylulose and D-sorbose. Its activity was maximal at pH 9 and 40 degrees C while being enhanced by Mn(2+). At pH 9 and 40 degrees C, 118 g D-psicose l(-1) was produced from 700 g D-fructose l(-1) after 3 h.

  13. Mathematical model for the analytical signal of an herbicide sensor based on the reaction centre of Rhodobacter sphaeroides.

    Science.gov (United States)

    Andreu, Yolanda; Baldini, Francesco; Giannetti, Ambra; Mencaglia, Andrea

    2005-01-30

    This paper introduces a mathematical model which makes it possible both to determine the concentration of photosynthetic herbicides and to obtain a quantitative parameter in order to compare their activity using a previously described sensing system. The working principle involves the changes in absorption properties at 860nm of the reaction centre (RC) isolated from the bacteria Rhodobacter sphaeroides when photosynthetic herbicides are present. The method has been used for the determination and activity comparison of five photosynthetic herbicides: diuron, atrazine, terbutryn, terbuthylazine and simazine. Detection limits obtained were 2.2, 0.75, 0.046, 0.25, and 1.4muM, respectively. The resulting order for the different herbicides according to their action on RC was: terbutryn > terbuthylazine > atrazine > simazine > diuron.

  14. Favreauite, a new selenite mineral from the El Dragon mine, Bolivia

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Stuart J. [Museum Victoria, Melbourne, VIC (Australia). Geosciences; Kampf, Anthony R. [Natural History Museum of Los Angeles, CA (United States). Mineral Sciences Dept.; Christy, Andrew G. [Australian National Univ., Canberra, ACT (Australia). Centre for Advanced Microscopy; Housley, Robert M. [California Institute of Technology, Pasadena, CA (United States). Div. of Geological and Planetary Sciences; Chen, Yu-Sheng [Chicago Univ., IL (United States). Center for Advanced Radiation Sources; Steele, Ian M. [Chicago Univ., IL (United States). Center for Advanced Radiation Sources; Thorne, Brent

    2014-07-01

    Favreauite, ideally PbBiCu{sub 6}O{sub 4}(SeO{sub 3}){sub 4}.H{sub 2}O, is a new secondary selenite mineral from the El Dragon mine, Antonio Quijarro Province, Potosi Department, Bolivia. The mineral occurs in vughs in a matrix of (Co, Cu)-rich penroseite, dolomite and goethite. Associated minerals are: ahlfeldite, allophane, calcite, chalcomenite, malachite, molybdomenite and an unnamed Al selenite. Favreauite forms tiny green square tbular crystals, flattened on {001}, up to 0.1 mm on edge and 0.01 mm thick, occurring in subparallel and divergent groups. The Mohs hardness of favreauite is estimated as ∼3; it has perfect cleavage on {001}, an irregular fracture and a vitreous lustre. The calculated density based on the empirical formula is 4.851 g cm{sup -3}. Favreauite is uniaxial (-), with mean refractive index estimated as 1.854 from the Gladstone-Dale relationship. It is pleochroic in shades of green, O < E. Electron microprobe analyses gave the empirical formula Pb{sub 0.95}Ca{sub 0.17}Bi{sub 0.90}Cu{sub 5.81}Se{sub 4.10}O{sub 16}(OH) . 1H{sub 2}O, based on 18 O pfu. The Raman spectrum shows strong SeO{sub 3} bands at 847 cm{sup -1} (ν{sub 1}), 764 and 795 cm{sup -1} (ν{sub 3}), 493 and 542 cm{sup -1} (ν{sub 2}), and 320 and 392 cm{sup -1} (ν{sub 4}). Favreauite is tetragonal, space group P4/n, with the unit-cell parameters: a = 9.860(4) Aa, c = 9.700(5) Aa, V = 943.0(9) Aa{sup 3} and Z = 2. The eight strongest lines in the X-ray powder diffraction pattern are [d{sub obs}/Aa (I) (hkl)]: 5.67(100)(111), 3.470(76)(220,202), 3.190(35)(003), 2.961(40)(311,113), 2.709(33)(302,203), 2.632(34)(231,312), 2.247(36)(331,133), and 1.6652(33)(305,513,531). The crystal structure was refined to R{sub 1} = 0.0329 for 1354 observed reflections [F{sub o} > 4σF{sub o}] and 0.0356 for all 1432 unique reflections. Favreauite is a close structural relative of nabokoite, KCu{sub 7}Te{sup 4+}O{sub 4}(SO{sub 4}){sub 5}Cl, and atlasovite, KCu{sub 6}Fe{sup 3+}BiO{sub 4}(SO

  15. Field study of time-dependent selenium partitioning in soils using isotopically enriched stable selenite tracer

    International Nuclear Information System (INIS)

    Di Tullo, Pamela; Pannier, Florence; Thiry, Yves; Le Hécho, Isabelle; Bueno, Maïté

    2016-01-01

    A better understanding of selenium fate in soils at both short and long time scales is mandatory to consolidate risk assessment models relevant for managing both contamination and soil fertilization issues. The purpose of this study was thus to investigate Se retention processes and their kinetics by monitoring time-dependent distribution/speciation changes of both ambient and freshly added Se, in the form of stable enriched selenite-77, over a 2-years field experiment. This study clearly illustrates the complex reactivity of selenium in soil considering three methodologically defined fractions (i.e. soluble, exchangeable, organic). Time-dependent redistribution of Se-77 within solid-phases having different reactivity could be described as a combination of chemical and diffusion controlled processes leading to its stronger retention. Experimental data and their kinetic modeling evidenced that transfer towards less labile bearing phases are controlled by slow processes limiting the overall sorption of Se in soils. These results were used to estimate time needed for "7"7Se to reach the distribution of naturally present selenium which may extend up to several decades. Ambient Se speciation accounted for 60% to 100% of unidentified species as function of soil type whereas "7"7Se(IV) remained the more abundant species after 2-years field experiment. Modeling Se in the long-term without taking account these slow sorption kinetics would thus result in underestimation of Se retention. When using models based on K_d distribution coefficient, they should be at least reliant on ambient Se which is supposed to be at equilibrium.

  16. Field study of time-dependent selenium partitioning in soils using isotopically enriched stable selenite tracer

    Energy Technology Data Exchange (ETDEWEB)

    Di Tullo, Pamela, E-mail: pamela.ditullo@univ-pau.fr [Laboratoire de Chimie Analytique Bio-Inorganique et Environnement (LCABIE), Université de Pau et des Pays de l' Adour/CNRS, UMR 5254, IPREM, Hélioparc, 2 Avenue du Président Angot, 64053 Pau Cedex 9 (France); Andra, Research and Development Division, Parc de la Croix Blanche, 1-7 rue Jean Monnet, 92298 Châtenay-Malabry Cedex (France); Pannier, Florence, E-mail: florence.pannier@univ-pau.fr [Laboratoire de Chimie Analytique Bio-Inorganique et Environnement (LCABIE), Université de Pau et des Pays de l' Adour/CNRS, UMR 5254, IPREM, Hélioparc, 2 Avenue du Président Angot, 64053 Pau Cedex 9 (France); Thiry, Yves, E-mail: yves.thiry@andra.fr [Andra, Research and Development Division, Parc de la Croix Blanche, 1-7 rue Jean Monnet, 92298 Châtenay-Malabry Cedex (France); Le Hécho, Isabelle, E-mail: isabelle.lehecho@univ-pau.fr [Laboratoire de Chimie Analytique Bio-Inorganique et Environnement (LCABIE), Université de Pau et des Pays de l' Adour/CNRS, UMR 5254, IPREM, Hélioparc, 2 Avenue du Président Angot, 64053 Pau Cedex 9 (France); Bueno, Maïté, E-mail: maite.bueno@univ-pau.fr [Laboratoire de Chimie Analytique Bio-Inorganique et Environnement (LCABIE), Université de Pau et des Pays de l' Adour/CNRS, UMR 5254, IPREM, Hélioparc, 2 Avenue du Président Angot, 64053 Pau Cedex 9 (France)

    2016-08-15

    A better understanding of selenium fate in soils at both short and long time scales is mandatory to consolidate risk assessment models relevant for managing both contamination and soil fertilization issues. The purpose of this study was thus to investigate Se retention processes and their kinetics by monitoring time-dependent distribution/speciation changes of both ambient and freshly added Se, in the form of stable enriched selenite-77, over a 2-years field experiment. This study clearly illustrates the complex reactivity of selenium in soil considering three methodologically defined fractions (i.e. soluble, exchangeable, organic). Time-dependent redistribution of Se-77 within solid-phases having different reactivity could be described as a combination of chemical and diffusion controlled processes leading to its stronger retention. Experimental data and their kinetic modeling evidenced that transfer towards less labile bearing phases are controlled by slow processes limiting the overall sorption of Se in soils. These results were used to estimate time needed for {sup 77}Se to reach the distribution of naturally present selenium which may extend up to several decades. Ambient Se speciation accounted for 60% to 100% of unidentified species as function of soil type whereas {sup 77}Se(IV) remained the more abundant species after 2-years field experiment. Modeling Se in the long-term without taking account these slow sorption kinetics would thus result in underestimation of Se retention. When using models based on K{sub d} distribution coefficient, they should be at least reliant on ambient Se which is supposed to be at equilibrium.

  17. Tissue concentration-time profile of selenium after sodium selenite administration to rats

    Energy Technology Data Exchange (ETDEWEB)

    Kaneko, Megumi; Natsuhori, Masahiro; Ito, Nobuhiko [Department of Veterinary Radiology and Radiation Biology, Kitasato University School of Veterinary Medicine, Towada, Aomori (Japan); Sera, Koichiro [Cyclotron Research Center, Iwate Medical University, Takizuka, Iwate (Japan); Futatsugawa, Shoji [Nishina Memorial Cyclotron Center (NMCC), Takizuka, Iwate (Japan)

    1999-07-01

    Selenium (Se) concentration-time profiles in plasma and organs including liver, kidney, heart, lung, spleen and brain of rats (Jcl Wister, 9 wks old, n=32) were investigated after a single intravenous (iv) / oral (po) administration of sodium selenite (dose is equivalent to 2 mg/kg b.w. of Se). The Se concentration was determined by PIXE analysis. Among the investigated biological samples, Se concentration was the highest in the kidney or liver, followed by the heart, lung or spleen, then plasma, and the brain. Se concentrations in these organs were 0.5 to 5 times of plasma Se. The distribution profiles of Se in the organs were dependent on the route of administration. Furthermore, their profiles appeared almost parallel to the plasma Se-concentration in a logarithmic scale. Compared to the Se concentration-time profiles in plasma and organs by the route of administration, po group showed about 1/4-1/2 of the Se concentration in iv group except for kidney. Kidney kept relatively higher concentration of Se, which was similar in the both groups. This may explain our recently published data that urinary excretion was similar in the both groups. The relative oral bioavailability of plasma and each organ was calculated by the ratio of area under the concentration-time curve after oral administration (AUCpo) to AUCiv. Each organ appeared to have their own bioavailability (i.e., liver 39%, kidney 97%, heart 37%, lung 18%, spleen 10%, and brain 72%), where plasma was 46%. These results highly suggested that different Se distribution in organs by the different route of administration was due to the different metabolic profile. (author)

  18. PIGMENT CONTENT OF Chlorella vulgaris BEIJ. UNDER INFLUENCE OF THE SODIUM SELENITE AND METALS IONS

    Directory of Open Access Journals (Sweden)

    O. I.

    2016-02-01

    Full Text Available The aim of the research was to determine the conditions obtaining in the aquaculture of Chlorella vulgaris Beij. algosubstantion enriched with selenium and bioactive metals. For this purpose, the content of seaweed pigments studied by the action of sodium selenite in a concentration based on Se4+: 0.5, 5.0, 10.0 and 20.0 mg / dm3 for 1, 3 and 7 days and while exposed 10.0 mg Se4 +/dm3 and Zn2+, Mn2 +, Co2 +, Cu2 +, Fe3 + in concentrations of 5.0 mg/dm 3, 0.25, 0.002, 0.008 and 0.05 mg/dm3, respectively, within 7 days of culturing. The content of pigments was determined spectrophotometrically, the cellular walls were given off in the percoll gradient and investigated microscopically. The pigments content in Ch. vulgaris increase by 1,5–2,5 times in comparison with control sample under the influence of 10 mg Se(IV/dm3 with and without metal ions. In the same condition a ratio of chlorophylls a/b increased, that accompanied by the formation in cells of the second cell wall as the sign of successful adaptation process in the Chlorella cells under the influence of these factors. Thus, the cultivation of chlorella, enriched with selenium and bioactive metals, is possible within 7 days under the influence of 10 mg Se (IV/dm3 and mentioned concentration of these metal ions.

  19. Syntheses and structures of three f-element selenite/hydroselenite compounds

    International Nuclear Information System (INIS)

    Burns, Wendy L.; Ibers, James A.

    2009-01-01

    The selenite/hydroselenite compounds Ce(SeO 3 )(HSeO 3 ), Tb(SeO 3 )(HSeO 3 ).2H 2 O, and Cs[U(SeO 3 )(HSeO 3 )].3H 2 O were synthesized by hydrothermal means at 453 K from the reaction of CeO 2 or Tb 4 O 7 or UO 2 with SeO 2 and CsCl (as a mineralizer). Ce(SeO 3 )(HSeO 3 ) crystallizes in the non-centrosymmetric orthorhombic space group Pca2 1 . The structure comprises a two-dimensional network of interconnected CeO 10 bicapped distorted square antiprisms and SeO 3 trigonal pyramids. Tb(SeO 3 )(HSeO 3 ).2H 2 O crystallizes in the non-centrosymmetric orthorhombic space group P2 1 2 1 2 1 . The structure features a two-dimensional layer of interconnected TbO 8 distorted square antiprisms and SeO 3 trigonal pyramids. Cs[U(SeO 3 )(HSeO 3 )].3H 2 O crystallizes in the centrosymmetric monoclinic space group P2 1 /n. The structure consists of two-dimensional layers of interconnected UO 7 pentagonal bipyramids and SeO 3 trigonal pyramids. The layers in all three structures are held together by hydrogen-bonding networks. - Graphical abstract: Structure of Ce[U(SeO 3 )(HSeO 3 )].3H 2 O (Cs, purple; U, black; Se, blue; O, red; O w , green; H, gray).

  20. Tissue concentration-time profile of selenium after sodium selenite administration to rats

    International Nuclear Information System (INIS)

    Kaneko, Megumi; Natsuhori, Masahiro; Ito, Nobuhiko; Sera, Koichiro; Futatsugawa, Shoji

    1999-01-01

    Selenium (Se) concentration-time profiles in plasma and organs including liver, kidney, heart, lung, spleen and brain of rats (Jcl Wister, 9 wks old, n=32) were investigated after a single intravenous (iv) / oral (po) administration of sodium selenite (dose is equivalent to 2 mg/kg b.w. of Se). The Se concentration was determined by PIXE analysis. Among the investigated biological samples, Se concentration was the highest in the kidney or liver, followed by the heart, lung or spleen, then plasma, and the brain. Se concentrations in these organs were 0.5 to 5 times of plasma Se. The distribution profiles of Se in the organs were dependent on the route of administration. Furthermore, their profiles appeared almost parallel to the plasma Se-concentration in a logarithmic scale. Compared to the Se concentration-time profiles in plasma and organs by the route of administration, po group showed about 1/4-1/2 of the Se concentration in iv group except for kidney. Kidney kept relatively higher concentration of Se, which was similar in the both groups. This may explain our recently published data that urinary excretion was similar in the both groups. The relative oral bioavailability of plasma and each organ was calculated by the ratio of area under the concentration-time curve after oral administration (AUCpo) to AUCiv. Each organ appeared to have their own bioavailability (i.e., liver 39%, kidney 97%, heart 37%, lung 18%, spleen 10%, and brain 72%), where plasma was 46%. These results highly suggested that different Se distribution in organs by the different route of administration was due to the different metabolic profile. (author)

  1. Effects of 14-day oral low dose selenium nanoparticles and selenite in rat—as determined by metabolite pattern determination

    DEFF Research Database (Denmark)

    Hadrup, Niels; Löschner, Katrin; Skov, Kasper

    2016-01-01

    Selenium (Se) is an essential element with a small difference between physiological and toxic doses. To provide more effective and safe Se dosing regimens, as compared to dosing with ionic selenium, nanoparticle formulations have been developed. However, due to the nano-formulation, unexpected...... toxic effects may occur. We used metabolite pattern determination in urine to investigate biological and/or toxic effects in rats administered nanoparticles and for comparison included ionic selenium at an equimolar dose in the form of sodium selenite. Low doses of 10 and 100 fold the recommended human...

  2. Méditation et pratique de soi chez Malebranche.

    Directory of Open Access Journals (Sweden)

    Éric Dubreucq

    2004-04-01

    Full Text Available Une étude des Méditations pour se disposer à l’Humilité et à la pénitence qui les replace dans le cadre des pratiques de son époque, par exemple, chez François de Sales, celles de l’oraison, de la méditation et de la contemplation, permet d’apercevoir que l’une des thèses majeures du malebranchisme, la vision en Dieu, est un effet instauré dans le destinataire par un dispositif textuel. Celui-ci tire sa puissance prescriptive de l’a priori pratique où il s’inscrit. C’est à une opération de production de soi que l’exercice spirituel donne lieu : l’analyse des quatre premières Méditations chrétiennes et métaphysiques, en particulier, montre que c’est une organisation de la substance personnelle que provoque le travail spirituel sur soi. Celui-ci consiste à déterminer le rapport à soi comme relation d’une vision attentive à une activité illuminante, par un décentrement textuel du « je » vers le « tu ».One of the major Malebranche’s assertion, that we see truth in God, is not a mere theoretical thesis. I study first the Méditations pour se disposer à l’Humilité et à la pénitence and compare them with François de Sales’ spiritual exercitations, and show that prayer, meditation and contemplation constitute the practical frameworks of this period. The text of the Méditations is an apparatus which is fit to cause an effect in its target – the self of the reader : the vision in God. The practical a priori of the meditation provides the text with prescriptive power to transform the self. Then I study the Méditations chrétiennes et métaphysiques i-iv : we see that Malebranche set his textual apparatus so that it prescribes its receiver a form of « work-on-one’s-self ». The self is here produced by the organisation of relationship between attentive vision and lighting action, and this structure is built in the self by a movement, induced by the text, which leads the self from

  3. Prévalence et facteurs associés à la surcharge pondérale chez les ...

    African Journals Online (AJOL)

    30% des adolescentes et près de 10% des garçons sont soit en surpoids, soit obèses. (McQuaide, 2008). Des études ont estimé la prévalence de la surcharge pondérale chez les adolescents mexicains à 19,8% et chez les adolescents égyptiens à 12.1%. Les facteurs de risque étaient l'âge, le niveau d'instruction,.

  4. Potential of Rhodobacter capsulatus Grown in Anaerobic-Light or Aerobic-Dark Conditions as Bioremediation Agent for Biological Wastewater Treatments

    OpenAIRE

    Stefania Costa; Saverio Ganzerli; Irene Rugiero; Simone Pellizzari; Paola Pedrini; Elena Tamburini

    2017-01-01

    The use of microorganisms to clean up wastewater provides a cheaper alternative to the conventional treatment plant. The efficiency of this method can be improved by the choice of microorganism with the potential of removing contaminants. One such group is photosynthetic bacteria. Rhodobacter capsulatus is a purple non-sulfur bacterium (PNSB) found to be capable of different metabolic activities depending on the environmental conditions. Cell growth in different media and conditions was teste...

  5. Selenite modulates the level of phenolics and nutrient element to alleviate the toxicity of arsenite in rice (Oryza sativa L.).

    Science.gov (United States)

    Chauhan, Reshu; Awasthi, Surabhi; Tripathi, Preeti; Mishra, Seema; Dwivedi, Sanjay; Niranjan, Abhishek; Mallick, Shekhar; Tripathi, Pratibha; Pande, Veena; Tripathi, Rudra Deo

    2017-04-01

    Arsenic (As) contamination of paddy rice is a serious threat all over the world particularly in South East Asia. Selenium (Se) plays important role in protection of plants against various abiotic stresses including heavy metals. Moreover, arsenite (AsIII) and selenite (SeIV) can be biologically antagonistic due to similar electronic configuration and sharing the common transporter for their uptake in plant. In the present study, the response of oxidative stress, phenolic compounds and nutrient elements was analyzed to investigate Se mediated As tolerance in rice seedlings during AsIII and SeIV exposure in hydroponics. Selenite (25µM) significantly decreased As accumulation in plant than As (25µM) alone treated plants. Level of oxidative stress related parameters viz., reactive oxygen species (ROS), lipid peroxidation, electrical conductivity, nitric oxide and pro-oxidant enzyme (NADPH oxidase), were in the order of As>As+Se>control>Se. Selenium ameliorated As phytotoxicity by increased level of phenolic compounds particularly gallic acid, protocatechuic acid, ferulic acid and rutin and thiol metabolism related enzymes viz., serine acetyl transferase (SAT) and cysteine synthase (CS). Selenium supplementation enhanced the uptake of nutrient elements viz., Fe, Mn, Co, Cu, Zn, Mo, and improved plant growth. The results concluded that Se addition in As contaminated environment might be an important strategy to reduce As uptake and associated phytotoxicity in rice plant by modulation of phenolic compounds and increased uptake of nutrient elements. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. A comparative study of ion exchange properties of antimony (III) tungstoselenite with those of antimony (III) tungstate and antimony (III) selenite

    International Nuclear Information System (INIS)

    Janardanan, C.; Nair, S.M.K.

    1996-01-01

    A new inorganic ion exchanger, antimony (III) tungstoselenite, has been prepared and characterised. Its exchange capacity and distribution coefficients for various metal ions and the effects of temperature and electrolyte concentrations on ion exchange capacity have been compared with antimony (III) tungstate and antimony (III) selenite. Six binary separations using the exchanger have been carried out. (author). 7 refs., 1 tab

  7. Effect of dietary sodium selenite, Se-enriched yeast and Se-enriched Chlorella on egg Se concentration, physical parameters of eggs and laying hen production

    Czech Academy of Sciences Publication Activity Database

    Skřivan, M.; Šimáně, J.; Dlouhá, G.; Doucha, Jiří

    2006-01-01

    Roč. 51, č. 4 (2006), s. 163-167 ISSN 1212-1819 Institutional research plan: CEZ:AV0Z50200510 Keywords : sodium selenite * se-yeast * se-chlorella Subject RIV: EE - Microbiology, Virology Impact factor: 0.421, year: 2006

  8. Separation and identification of selenotrisulfides in epithelial cell homogenates by LC-ICP-MS and LC-ESI-MS after incubation with selenite

    DEFF Research Database (Denmark)

    Gabel-Jensen, Charlotte; Gammelgaard, Bente; Bendahl, Lars

    2006-01-01

    . The presence of Cys-Se-SG and GS-Se-SG was verified by LC-ESI-MS. Selenotrisulfides were synthesized by reaction of L-cysteine and L-glutathione with sodium selenite. The reaction mixture contained three main products: selenodicysteine (Cys-Se-Cys), selenocysteine glutathione (Cys...

  9. Piqures massives par un essaim d�abeilles chez un enfant

    Directory of Open Access Journals (Sweden)

    Mohamed Adnane Berdai

    2011-10-01

    Full Text Available Les piqures multiples d�abeilles sont responsables d�envenimation severe. Nous rapportons un cas d�une attaque massive par un essaim d�abeilles chez un enfant de sept ans. Sa gravite est liee a la localisation cephalique et au nombre important des piqures qui etait d�environ 270. Ses complications etaient l�insuffisance renale, l�anemie et une conjonctivite. La prise en charge etait symptomatique avec bonne evolution clinique et biologique.

  10. Infection par le VIH chez les patientes atteintes de cancer du sein en ...

    African Journals Online (AJOL)

    L'objectif était de déterminer la prévalence de l'infection à VIH chez les patientes atteintes de cancer du sein et de comparer les caractéristiques anatomocliques et thérapeutiques de ces cancers du sein par rapports aux patientes non infectées par le VIH. Il s'agissait d'une étude rétrospective et analytique comparant les ...

  11. Prevalence de l'infection a VIH chez les patients victimes d'un ...

    African Journals Online (AJOL)

    Introduction: Le VIH/SIDA et son traitement antirétroviral sont associés à un risque élevé de maladies cardiovasculaires comme les accidents vasculaires cérébraux (AVC). L'objectif de cette étude était d'estimer la prévalence du VIH et d'identifier ses facteurs associés chez les patients hospitalisés pour un AVC. Méthode: ...

  12. Épidémiologie de l'intoxication par envenimation chez les enfants ...

    African Journals Online (AJOL)

    Introduction: L'intoxication par envenimation est l'ensemble des manifestations locales et générales induites par la pénétration dans l'organisme d'une substance toxique produite par un animal venimeux. Le but de notre travail était d'étudier les signes cliniques des intoxications par envenimation chez les enfants de 0 à 15 ...

  13. Evaluation des complications cardiaques chez les hémodialysés ...

    African Journals Online (AJOL)

    Introduction: L'évaluation cardiovasculaire est essentielle en hémodialyse périodique car les affections cardiovasculaires sont la première cause de mortalité chez les hémodialysés chroniques. Nous avons conduit cette étude afin de déterminer la prévalence et le type des différentes complications cardiovasculaires et ...

  14. La surveillance des abords vasculaires chez les hémodialysés ...

    African Journals Online (AJOL)

    La fistule artério veineuse a présenté très peu de complications chez les patients. Mots clés : Abord vasculaire, Hémodialyse, insuffisance rénale chronique. English abstract. Monitoring of vascular access in chronic hemodialysis patients at the National Hospital of Niamey Lamordé The purpose of this cross-sectional study ...

  15. Evaluation de la prise en charge du paludisme chez les enfants de ...

    African Journals Online (AJOL)

    Devant l'ampleur du paludisme en pays intertropicaux le rôle du personnel soignant dans la réduction de la fréquence des cas de paludisme grave et de son taux de létalité devient évident. Nous avons alors voulu évaluer la qualité de la prise en charge de cette affection chez l'enfant de moins de cinq ans dans un hôpital ...

  16. MANIfESTATIONS ORL dU RGO ChEz L'ENfANT

    African Journals Online (AJOL)

    7 déc. 2011 ... Le volume de salive déglutie et sa concentration en bicarbonates semblent jouer un rôle primordial dans la clairance œsophagienne (4, 6). vidange gastrique : Des études récentes ont montré qu'il existait une gastro- parésie et des troubles de la motricité gastro-intestinale chez des enfants atteints de RGO ...

  17. Original Paper Evaluation de la fonction rénale chez les patients ...

    African Journals Online (AJOL)

    Evaluation de la fonction rénale chez les patients atteints de maladie cardio vasculaire (MCV) : comparaison entre ... Mots clés : Cystatine C, créatinine, insuffisance rénale, débit de filtration glomérulaire, maladies cardiovasculaires. Evaluation of the ... L'insuffisance rénale chronique (IRC) et les maladies cardiovasculaires ...

  18. Lymphome B à grandes cellules primitif du médiastin chez la femme ...

    African Journals Online (AJOL)

    Les patientes ont été adressées à l'institut national d'oncologie pour prise en charge thérapeutique. Le pronostic du LBPM est réservé, il survient volontiers chez des femmes jeunes, ce qui rend d'autant plus nécessaire une thérapeutique agressive afin d'améliorer le taux de survie. The Pan African Medical Journal 2016; ...

  19. Les besoins en isoleucine, valine et leucine chez le porcelet entre 7 et 15 kg

    DEFF Research Database (Denmark)

    Assadi Soumeh, Elham; van Milgen, Jaap; Sloth, Niels Morten

    2015-01-01

    croissance s’ils sont fournis en deçà du besoin. Des études de métaanalyse révèlent que peu de données de type dose‐réponse sont disponibles chez le porcelet pour l’Ile, notamment avec des aliments exempts de cellules de sang, et la Val (van Milgen et al., 2012, 2013). Par ailleurs, une revue de la...

  20. Sodium selenite supplementation during pregnancy and lactation promotes anxiolysis and improves mnemonic performance in wistar rats' offspring.

    Science.gov (United States)

    Laureano-Melo, Roberto; Império, Güínever Eustáquio do; da Silva-Almeida, Claudio; Kluck, George Eduardo Gabriel; Cruz Seara, Fernando de Azevedo; da Rocha, Fábio Fagundes; da Silveira, Anderson Luiz Bezerra; Reis, Luís Carlos; Ortiga-Carvalho, Tania Maria; da Silva Côrtes, Wellington

    2015-11-01

    Selenium is a micronutrient which is part of selenoprotein molecules and participates in a vast number of physiological roles and, among them,we have fetal and neonatal development. Therefore, the aimof this studywas to evaluate possible behavioral changes in offspring of female rats supplemented during pregnancy and lactation with sodium selenite. To address that, we treated two groups of female rats by saline or sodium selenite at a dose of 1mg/kg through oral route and performed neurochemical and behavioral tests. In the offspring, the thyroid profile and hippocampal neurochemistrywere evaluated. Behavioral testswere performed in pups both during childhood and adulthood. We found out that selenium (Se) supplementation increased serum levels of triiodothyronine (25%, p b 0.001) and thyroxine (18%, p b 0.05) and promoted a tryptophan hydroxylase 2 (TPH 2) expression decrease (17%, p b 0.01) and tyrosine hydroxylase (TH) expression increase (202%, p b 0.01) in the hippocampus. The cholinesterase activity was decreased (28%, p b 0.01) in Se supplemented rats, suggesting a neurochemical modulation in the hippocampal activity. During childhood, the Sesupplemented offspring had a reduction in anxiety-like behavior both in elevated plus maze test and in light–dark box test. In adulthood, Se-treated pups had an increase in the locomotor activity (36%, p b 0.05) and in rearing episodes (77%, p b 0.001) in the open field test, while in the elevated plus maze test they also exhibited an increase in the time spent in the open arms (243%, p b 0.01). For the object recognition test, Se-treated offspring showed increase in the absolute (230.16%, p b 0.05) and relative index discrimination (234%, p b 0.05). These results demonstrate that maternal supplementation by sodium selenite promoted psychobiological changes both during childhood and adulthood. Therefore, the behavioral profile observed possibly can be explained by neurochemical changes induced by thyroid hormones during

  1. Les effets neurocognitifs de la vitamine D chez la personne âgée

    Directory of Open Access Journals (Sweden)

    Annweiler Cédric

    2014-05-01

    Full Text Available Une alimentation saine, en particulier la consommation régulière d’aliments riches en vitamine D, est un facteur protecteur contre la survenue de pathologie démentielle chez la personne âgée. Outre ses propriétés traditionnellement reconnues de régulation du métabolisme phosphocalcique, la vitamine D est une hormone neurostéroïde indispensable au fonctionnement neurophysiologique (régulation de neurotransmetteurs et de neurotrophines avec, en plus, une action neuroprotectrice anti-inflammatoire et anti-oxydante. Au contraire son insuffisance, extrêmement prévalente chez la personne âgée, pourrait engendrer des dysfonctionnements du système nerveux central, expliquant en partie les troubles cognitifs rencontrés dans cette population. L’épidémiologie est cohérente avec cette notion et rapporte une association entre hypovitaminose D et trouble cognitif, que ce soit en population âgée générale ou chez le malade Alzheimer. Les essais d’intervention confirment la relation de causalité et quantifient l’efficacité cognitive de la supplémentation vitaminique D chez la personne âgée, ce qui suscite des perspectives en matière de prévention primo-secondaire des troubles cognitifs chez la personne âgée par un apport exogène de vitamine D. En particulier, tandis que les traitements anti-démence symptomatiques actuellement disponibles ne font que ralentir transitoirement le déclin cognitif, les futures possibilités de traitement pourraient reposer sur des combinaisons médicamenteuses luttant contre plusieurs mécanismes neurodégénératifs à la fois. À ce titre, la vitamine D améliore l’efficacité de la mémantine en termes de protection neuronale et de prévention du déclin cognitif au cours de la maladie d’Alzheimer.

  2. Overexpression of pucC improves the heterologous protein expression level in a Rhodobacter sphaeroides expression system.

    Science.gov (United States)

    Cheng, L; Chen, G; Ding, G; Zhao, Z; Dong, T; Hu, Z

    2015-04-27

    The Rhodobacter sphaeroides system has been used to express membrane proteins. However, its low yield has substantially limited its application. In order to promote the protein expression capability of this system, the pucC gene, which plays a crucial role in assembling the R. sphaeroides light-harvesting 2 complex (LH2), was overexpressed. To build a pucC overexpression strain, a pucC overexpression vector was constructed and transformed into R. sphaeroides CQU68. The overexpression efficiency was evaluated by quantitative real-time polymerase chain reaction. A well-used reporter β-glucuronidase (GUS) was fusion-expressed with LH2 to evaluate the heterologous protein expression level. As a result, the cell culture and protein in the pucC overexpression strain showed much higher typical spectral absorption peaks at 800 and 850 nm compared with the non-overexpression strain, suggesting a higher expression level of LH2-GUS fusion protein in the pucC overexpression strain. This result was further confirmed by Western blot, which also showed a much higher level of heterologous protein expression in the pucC overexpression strain. We further compared GUS activity in pucC overexpression and non-overexpression strains, the results of which showed that GUS activity in the pucC overexpression strain was approximately ten-fold that in the non-overexpression strain. These results demonstrate that overexpressed pucC can promote heterologous protein expression levels in R. sphaeroides.

  3. Probing energy transfer events in the light harvesting complex 2 (LH2) of Rhodobacter sphaeroides with two-dimensional spectroscopy.

    Science.gov (United States)

    Fidler, Andrew F; Singh, Ved P; Long, Phillip D; Dahlberg, Peter D; Engel, Gregory S

    2013-10-21

    Excitation energy transfer events in the photosynthetic light harvesting complex 2 (LH2) of Rhodobacter sphaeroides are investigated with polarization controlled two-dimensional electronic spectroscopy. A spectrally broadened pulse allows simultaneous measurement of the energy transfer within and between the two absorption bands at 800 nm and 850 nm. The phased all-parallel polarization two-dimensional spectra resolve the initial events of energy transfer by separating the intra-band and inter-band relaxation processes across the two-dimensional map. The internal dynamics of the 800 nm region of the spectra are resolved as a cross peak that grows in on an ultrafast time scale, reflecting energy transfer between higher lying excitations of the B850 chromophores into the B800 states. We utilize a polarization sequence designed to highlight the initial excited state dynamics which uncovers an ultrafast transfer component between the two bands that was not observed in the all-parallel polarization data. We attribute the ultrafast transfer component to energy transfer from higher energy exciton states to lower energy states of the strongly coupled B850 chromophores. Connecting the spectroscopic signature to the molecular structure, we reveal multiple relaxation pathways including a cyclic transfer of energy between the two rings of the complex.

  4. Probing energy transfer events in the light harvesting complex 2 (LH2) of Rhodobacter sphaeroides with two-dimensional spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Fidler, Andrew F.; Singh, Ved P.; Engel, Gregory S. [Department of Chemistry, The Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637 (United States); Long, Phillip D.; Dahlberg, Peter D. [Graduate Program in the Biophysical Sciences, The University of Chicago, Chicago, Illinois 60637 (United States)

    2013-10-21

    Excitation energy transfer events in the photosynthetic light harvesting complex 2 (LH2) of Rhodobacter sphaeroides are investigated with polarization controlled two-dimensional electronic spectroscopy. A spectrally broadened pulse allows simultaneous measurement of the energy transfer within and between the two absorption bands at 800 nm and 850 nm. The phased all-parallel polarization two-dimensional spectra resolve the initial events of energy transfer by separating the intra-band and inter-band relaxation processes across the two-dimensional map. The internal dynamics of the 800 nm region of the spectra are resolved as a cross peak that grows in on an ultrafast time scale, reflecting energy transfer between higher lying excitations of the B850 chromophores into the B800 states. We utilize a polarization sequence designed to highlight the initial excited state dynamics which uncovers an ultrafast transfer component between the two bands that was not observed in the all-parallel polarization data. We attribute the ultrafast transfer component to energy transfer from higher energy exciton states to lower energy states of the strongly coupled B850 chromophores. Connecting the spectroscopic signature to the molecular structure, we reveal multiple relaxation pathways including a cyclic transfer of energy between the two rings of the complex.

  5. Probing energy transfer events in the light harvesting complex 2 (LH2) of Rhodobacter sphaeroides with two-dimensional spectroscopy

    International Nuclear Information System (INIS)

    Fidler, Andrew F.; Singh, Ved P.; Engel, Gregory S.; Long, Phillip D.; Dahlberg, Peter D.

    2013-01-01

    Excitation energy transfer events in the photosynthetic light harvesting complex 2 (LH2) of Rhodobacter sphaeroides are investigated with polarization controlled two-dimensional electronic spectroscopy. A spectrally broadened pulse allows simultaneous measurement of the energy transfer within and between the two absorption bands at 800 nm and 850 nm. The phased all-parallel polarization two-dimensional spectra resolve the initial events of energy transfer by separating the intra-band and inter-band relaxation processes across the two-dimensional map. The internal dynamics of the 800 nm region of the spectra are resolved as a cross peak that grows in on an ultrafast time scale, reflecting energy transfer between higher lying excitations of the B850 chromophores into the B800 states. We utilize a polarization sequence designed to highlight the initial excited state dynamics which uncovers an ultrafast transfer component between the two bands that was not observed in the all-parallel polarization data. We attribute the ultrafast transfer component to energy transfer from higher energy exciton states to lower energy states of the strongly coupled B850 chromophores. Connecting the spectroscopic signature to the molecular structure, we reveal multiple relaxation pathways including a cyclic transfer of energy between the two rings of the complex

  6. Phototrophic hydrogen production from glucose by pure and co-cultures of Clostridium butyricum and Rhodobacter sphaeroides

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Herbert H.P.; Zhu, Heguang; Zhang, Tong [Centre for Environmental Engineering Research, Department of Civil Engineering, University of Hong Kong, Pokfulam Road, Hong Kong (China)

    2006-12-15

    Phototrophic hydrogen production from glucose by pure and co-cultures of Clostridium butyricum and Rhodobacter sphaeroides was studied in batch experiments. Results showed that in all batches hydrogen was produced after a lag phase of about 10h; pure culture of R. sphaeroides produced hydrogen at rates substantially lower than C. butyricum. In co-culture systems, R. sphaeroides even with cell populations 5.9 times higher still could not compete with C. butyricum for glucose. In co-culture systems, R. sphaeroides syntrophically interacted with C. butyricum, using the acetate and butyrate produced by the latter as substrate for hydrogen production. Hydrogen production was ceased in all batches when the pH was lowered to the level of pH 6.5, resulting from the accumulation of fatty acids. It was also demonstrated in this study that fluorescence in situ hybridization (FISH) was an effective means for the quantification of the relative abundance of individual bacteria in a co-culture system. (author)

  7. Structural model and excitonic properties of the dimeric RC-LH1-PufX complex from Rhodobacter sphaeroides

    International Nuclear Information System (INIS)

    Sener, Melih; Hsin, Jen; Trabuco, Leonardo G.; Villa, Elizabeth; Qian, Pu; Hunter, C. Neil; Schulten, Klaus

    2009-01-01

    The light-harvesting apparatus of the purple bacterial photosynthetic unit consists of a pool of peripheral light-harvesting complexes that transfer excitation energy to a reaction center (RC) via the surrounding pigment-protein complex LH1. Recent electron microscopy and atomic force microscopy studies have revealed that RC-LH1 units of Rhodobacter (Rba.) sphaeroides form membrane-bending dimeric complexes together with the polypeptide PufX. We present a structural model for these RC-LH1-PufX dimeric complexes constructed using the molecular dynamics flexible fitting method based on an EM density map. The arrangement of the LH1 BChls displays a distortion near the proposed location of the PufX polypeptide. The resulting atomic model for BChl arrays is used to compute the excitonic properties of the dimeric RC-LH1 complex. A comparison is presented between the structural and excitonic features of the S-shaped dimeric BChl array of Rba. sphaeroides and the circular BChl arrangement found in other purple bacteria

  8. Resonance Raman spectroscopy of 2H-labelled spheroidenes in petroleum ether and in the Rhodobacter sphaeroides reaction centre.

    Science.gov (United States)

    Kok, P; Köhler, J; Groenen, E J; Gebhard, R; van der Hoef, I; Lugtenburg, J; Farhoosh, R; Frank, H A

    1997-03-01

    As a step towards the structural analysis of the carotenoid spheroidene in the Rhodobacter sphaeroides reaction centre, we present the resonance Raman spectra of 14-2H, 15-2H, 15'-2H, 14'-2H, 14,15'-2H2 and 15-15'-2H2 spheroidenes in petroleum ether and, except for 14,15'-2H2 spheroidene, in the Rb. sphaeroides R26 reaction center (RC). Analysis of the spectral changes upon isotopic substitution allows a qualitative assignment of most of the vibrational bands to be made. For the all-trans spheroidenes in solution the resonance enhancement of the Raman bands is determined by the participation of carbon carbon stretching modes in the centre of the conjugated chain, the C9 to C15' region. For the RC-bound 15,15'-cis spheroidenes, enhancement is determined by the participation of carbon-carbon stretching modes in the centre of the molecule, the C13 to C13' region. Comparison of the spectra in solution and in the RC reveals evidence for an out-of-plane distortion of the RC-bound spheroidene in the central C14 to C14' region of the carotenoid. The characteristic 1240 cm-1 band in the spectrum of the RC-bound spheroidene has been assigned to a normal mode that contains the coupled C12-C13 and C13'-C12' stretch vibrations.

  9. Direct visualization of exciton reequilibration in the LH1 and LH2 complexes of Rhodobacter sphaeroides by multipulse spectroscopy.

    Science.gov (United States)

    Cohen Stuart, Thomas A; Vengris, Mikas; Novoderezhkin, Vladimir I; Cogdell, Richard J; Hunter, C Neil; van Grondelle, Rienk

    2011-05-04

    The dynamics of the excited states of the light-harvesting complexes LH1 and LH2 of Rhodobacter sphaeroides are governed, mainly, by the excitonic nature of these ring-systems. In a pump-dump-probe experiment, the first pulse promotes LH1 or LH2 to its excited state and the second pulse dumps a portion of the excited state. By selective dumping, we can disentangle the dynamics normally hidden in the excited-state manifold. We find that by using this multiple-excitation technique we can visualize a 400-fs reequilibration reflecting relaxation between the two lowest exciton states that cannot be directly explored by conventional pump-probe. An oscillatory feature is observed within the exciton reequilibration, which is attributed to a coherent motion of a vibrational wavepacket with a period of ∼150 fs. Our disordered exciton model allows a quantitative interpretation of the observed reequilibration processes occurring in these antennas. Copyright © 2011 Biophysical Society. Published by Elsevier Inc. All rights reserved.

  10. Pigments content in Сhlorella vulgaris under the influence of the sodium selenite and the ions of metals

    Directory of Open Access Journals (Sweden)

    O. I. Bodnar

    2016-01-01

    Full Text Available We investigated the content of pigments in Chlorella vulgaris Beij. (Chlorophyta under the influence of sodium selenite in concentrations based on Se4+ 0.5, 5.0, 10.0 and 20.0 mg/dm3 during one, three and seven days and under the influence of the simultaneous action of selenite in concentrations 10 mg Se4+/dm3 and ions of Zn2+, Mn2+, Co2+,Cu2+, Fe3+ in concentrations 5.00, 0.25, 0.05, 0.008 and 0.002 mg/dm3over seven days. This research was carried out to establish the conditions for obtaining algal lipidis substance enriched with selenium and biogenic metals in the aquaculture. The content of pigments was determined spectrophotometrically, the cellular walls were separatedby centrifuge in the percoll gradient and investigated microscopically. The pigments content in the Ch. vulgaris increased by 1.5–2.5 times in comparison with the control sample under the influence of 10 mg Se4+/dm3 with and without metal ions, in all variants of experimental influence due to binding of SeО32– with proteins and lipids. We found that selenium was included in all lipid fractions (triacylglycerols, dyacylglycerols, phospholipids, nonetherified fatty acids; the maximum amount of selenium-containing lipids wasrecorded in chloroplasts. The increase in the contents of carotenoids caused by the actions of experimental factors played an exceptional role in the mechanism of antioxidant protection that prevents destruction of chlorophyll and, accordingly, increases its amount in cells. Changes in the functioning of the photosynthetic apparatus of Ch. vulgaris affect the whole complex of metabolic transformation. Thus, the successful cultivation of chlorella, enriched with selenium and biogenic metals, is possible within seven days under the influence of 10 mg Se4+/dm3 and the above-mentioned concentration of metal ions.

  11. Interaction of Coenzyme Q10 with Liposomes and its Impact on Suppression of Selenite – Induced Experimental Cataract

    Directory of Open Access Journals (Sweden)

    Medhat Wahba Shafaa

    2018-03-01

    Full Text Available Purpose: To stress the influence of Coenzyme Q10 (CoQ10 on the structural properties of liposomes as model membranes and to investigate the possible role of CoQ10 or CoQ10 doped in liposomes when topically instilled as eye drops, in preventing cataract. Methods: The molecular interaction between liposomes and Coenzyme Q10 was examined using differential scanning calorimetry (DSC and Fourier transform infrared spectroscopy (FTIR. Rat pups were randomly divided into six groups comprising 15 pups. Group (1, control group. Group (2, untreated model of cataract, received a single subcutaneous injection of sodium selenite. Instillation of pure CoQ10 (Group 3, CoQ10 encapsulated into neutral (Group 4, positive (Group 5 and negative (Group 6 Dipalmitoyl phosphatidylcholine (DPPC liposomes on the opacification of lenses in rat pups after sodium selenite injection was topically received. Results: The incorporated CoQ10 is probably associated with lipid bilayers where it interacts to a large extent and perturbs them. This results in strong broadening and shift to lower temperature (94°C of the major characteristic endothermic peak of pure DPPC at 105°C. FTIR showed that the incorporation of CoQ10 into DPPC induces a conformational change in the polar region of DPPC. Ophthalmological and Biochemical studies revealed that CoQ10 alone followed by negatively charged liposomes doped with CoQ10 are more effective in reducing the progress of cataract as well as improving the lens soluble proteins levels and total antioxidant capacity. Conclusion: The interactions of CoQ10 with membrane systems may contribute to a better understanding of CoQ10 physiological properties and the development of therapeutically advanced systems.

  12. Topologically and geometrically flexible structural units in seven new organically templated uranyl selenates and selenite-selenates

    Science.gov (United States)

    Gurzhiy, Vladislav V.; Kovrugin, Vadim M.; Tyumentseva, Olga S.; Mikhaylenko, Pavel A.; Krivovichev, Sergey V.; Tananaev, Ivan G.

    2015-09-01

    Single crystals of seven novel uranyl oxysalts of selenium with protonated methylamine molecules, [C2H8N]2[(UO2)(SeO4)2(H2O)] (I), [C2H8N]2[(UO2)2(SeO4)3(H2O)] (II), [C4H15N3][H3O]0.5[(UO2)2(SeO4)2.93(SeO3)0.07(H2O)](NO3)0.5 (III), [C2H8N]3[H5O2][(UO2)2(SeO4)3(H2O)2]2(H2O)5 (IV), [C2H8N]2[H3O][(UO2)3(SeO4)4(HSeO3)(H2O)](H2SeO3)0.2 (V), [C4H12N]3[H3O][(UO2)3(SeO4)5(H2O)] (VI), and [C2H8N]3(C2H7N)[(UO2)3(SeO4)4(HSeO3)(H2O)] (VII) have been prepared by isothermal evaporation from aqueous solutions. Their crystal structures have been solved by direct methods and their uranyl selenate and selenite-selenate units investigated using black-and-white graphs from the viewpoints of topology of interpolyhedral linkages and isomeric variations. The crystal structure of IV is based upon complex layers with unique topology, which has not been observed previously in uranyl selenates. Investigations of the statistics and local distribution of the U-Obr-Se bond angles demonstrates that shorter angles associate with undulations, whereas larger angles correspond to planar areas of the uranyl selenite layers.

  13. Toxicity of selenite in the unicellular green alga Chlamydomonas reinhardtii: Comparison between effects at the population and sub-cellular level

    International Nuclear Information System (INIS)

    Morlon, Helene; Fortin, Claude; Floriani, Magali; Adam, Christelle; Garnier-Laplace, Jacqueline; Boudou, Alain

    2005-01-01

    The toxicity of selenium in aquatic ecosystems is mainly linked to its uptake and biotransformation by micro-organisms, and its subsequent transfer upwards into the food chain. Thus, organisms at low trophic level, such as algae, play a crucial role. The aim of our study was to investigate the biological effects of selenite on Chlamydomonas reinhardtii, both at the sub-cellular level (effect on ultrastructure) and at the population level (effect on growth). The cells were grown under batch culture conditions in well-defined media and exposed to waterborne selenite at concentrations up to 500 μM; i.e. up to lethal conditions. Based on the relationship between Se concentration and cell density achieved after a 96 h exposure period, an EC 50 of 80 μM with a 95% confidence interval ranging between 64 and 98 μM was derived. No adaptation mechanisms were observed: the same toxicity was quantified for algae pre-contaminated with Se. The inhibition of growth was linked to impairments observed at the sub-cellular level. The intensity of the ultrastructural damages caused by selenite exposure depended on the level and duration of exposure. Observations by TEM suggested chloroplasts as the first target of selenite cytotoxicity, with effects on the stroma, thylakoids and pyrenoids. At higher concentrations, we could observe an increase in the number and volume of starch grains. For cells collected at 96 h, electron-dense granules were observed. Energy-dispersive X-ray microanalysis revealed that these granules contained selenium and were also rich in calcium and phosphorus. This study confirms that the direct toxicity of selenite on the phytoplankton biomass is not likely to take place at concentrations found in the environment. At higher concentrations, the link between effects at the sub-cellular and population levels, the over-accumulation of starch, and the formation of dense granules containing selenium are reported for the first time in the literature for a

  14. Dietary Effect of Selenium-enriched Radish Sprouts, Vitamin E, and Rhodobacter capsulatus on Hypocholesterolemia and Immunity of Broiler

    Directory of Open Access Journals (Sweden)

    Tsujii H

    2017-06-01

    Full Text Available The study was designed to investigate the effects of dietary Selenium-enriched radish sprouts (Se-RS, Vitamin E (Vit E, and Rhodobacter capsulatus (RC on immunity, cholesterol concentration, and fatty acid composition in broiler meat. A total of 100 two-week-old male broiler chicks were randomly assigned into five dietary groups: I Control; II Se-RS (5 μg/kg Se-RS; III Se-RS+RC (5 μg/kg Se-RS + 0.2 g/kg RC; IV Se-RS+Vit E (5 μg/kg Se-RS + 50 mg/kg Vit E and V Se-RS+RC+Vit E (5 μg/kg Se-RS + 0.2 g/kg RC + 50 mg/kg Vit E. Diets and clean drinking water were offered ad libitum. After the end of 3-wk of feeding period, serum cholesterol and triglycerides concentrations were lower (P < 0.05 in broilers fed Se-RS + RC + Vit E supplemented diet compared to the control diet. At the end of the 6-wk feeding period, birds fed the Se-RS+RC+Vit E diet significantly (P < 0.05 reduced cholesterol and triglycerides concentrations and improved the ratio of unsaturated fatty acids to saturated fatty acids in broiler meat. The highest (P < 0.05 number of leukocytes was observed in broilers fed Se-RS+RC+Vit E supplemented diet. Foot web index and weights of spleen, bursa, and thymus were significantly (P < 0.05 higher in birds fed Se-RS+RC+Vit E compared to the control diet. Our findings suggest that there are dual benefits of supplementing broiler diets with Se-RS+RC+Vit E because of improvements in the bird’s immunity and meat quality that is important for health conscious consumers.

  15. Electron spin relaxation enhancement measurements of interspin distances in human, porcine, and Rhodobacter electron transfer flavoprotein ubiquinone oxidoreductase (ETF QO)

    Science.gov (United States)

    Fielding, Alistair J.; Usselman, Robert J.; Watmough, Nicholas; Simkovic, Martin; Frerman, Frank E.; Eaton, Gareth R.; Eaton, Sandra S.

    2008-02-01

    Electron transfer flavoprotein-ubiquinone oxidoreductase (ETF-QO) is a membrane-bound electron transfer protein that links primary flavoprotein dehydrogenases with the main respiratory chain. Human, porcine, and Rhodobacter sphaeroides ETF-QO each contain a single [4Fe-4S] 2+,1+ cluster and one equivalent of FAD, which are diamagnetic in the isolated enzyme and become paramagnetic on reduction with the enzymatic electron donor or with dithionite. The anionic flavin semiquinone can be reduced further to diamagnetic hydroquinone. The redox potentials for the three redox couples are so similar that it is not possible to poise the proteins in a state where both the [4Fe-4S] + cluster and the flavoquinone are fully in the paramagnetic form. Inversion recovery was used to measure the electron spin-lattice relaxation rates for the [4Fe-4S] + between 8 and 18 K and for semiquinone between 25 and 65 K. At higher temperatures the spin-lattice relaxation rates for the [4Fe-4S] + were calculated from the temperature-dependent contributions to the continuous wave linewidths. Although mixtures of the redox states are present, it was possible to analyze the enhancement of the electron spin relaxation of the FAD semiquinone signal due to dipolar interaction with the more rapidly relaxing [4Fe-4S] + and obtain point-dipole interspin distances of 18.6 ± 1 Å for the three proteins. The point-dipole distances are within experimental uncertainty of the value calculated based on the crystal structure of porcine ETF-QO when spin delocalization is taken into account. The results demonstrate that electron spin relaxation enhancement can be used to measure distances in redox poised proteins even when several redox states are present.

  16. The photosynthetic bacteria Rhodobacter capsulatus and Synechocystis sp. PCC 6803 as new hosts for cyclic plant triterpene biosynthesis.

    Directory of Open Access Journals (Sweden)

    Anita Loeschcke

    Full Text Available Cyclic triterpenes constitute one of the most diverse groups of plant natural products. Besides the intriguing biochemistry of their biosynthetic pathways, plant triterpenes exhibit versatile bioactivities, including antimicrobial effects against plant and human pathogens. While prokaryotes have been extensively used for the heterologous production of other classes of terpenes, the synthesis of cyclic triterpenes, which inherently includes the two-step catalytic formation of the universal linear precursor 2,3-oxidosqualene, is still a major challenge. We thus explored the suitability of the metabolically versatile photosynthetic α-proteobacterium Rhodobacter capsulatus SB1003 and cyanobacterium Synechocystis sp. PCC 6803 as alternative hosts for biosynthesis of cyclic plant triterpenes. Therefore, 2,3-oxidosqualene production was implemented and subsequently combined with different cyclization reactions catalyzed by the representative oxidosqualene cyclases CAS1 (cycloartenol synthase, LUP1 (lupeol synthase, THAS1 (thalianol synthase and MRN1 (marneral synthase derived from model plant Arabidopsis thaliana. While successful accumulation of 2,3-oxidosqualene could be detected by LC-MS analysis in both hosts, cyclase expression resulted in differential production profiles. CAS1 catalyzed conversion to only cycloartenol, but expression of LUP1 yielded lupeol and a triterpenoid matching an oxidation product of lupeol, in both hosts. In contrast, THAS1 expression did not lead to cyclic product formation in either host, whereas MRN1-dependent production of marnerol and hydroxymarnerol was observed in Synechocystis but not in R. capsulatus. Our findings thus indicate that 2,3-oxidosqualene cyclization in heterologous phototrophic bacteria is basically feasible but efficient conversion depends on both the respective cyclase enzyme and individual host properties. Therefore, photosynthetic α-proteo- and cyanobacteria are promising alternative candidates

  17. Some aspects of sulphite metabolism in plants; Quelques aspects du metabolisme du sulfite chez les vegetaux

    Energy Technology Data Exchange (ETDEWEB)

    Perez-Milan, Hernan

    1958-05-15

    As sulphite appears to be an intermediate substance in the degradation of sulphur-containing amino acids, and has an important metabolic role, notably for plants, this research thesis aims at comparing transformations which may occur for a same chemical compound (the sulphite) in various organisms belonging to different species or kingdoms. More particularly, the author studied the formation of sulphite in vegetal tissues, and the oxidisation of sulphite into sulfate within these tissues. In vitro experiments have been performed with oat, while in vivo experiments have been performed on tobacco plants [French] Le sulfite apparait comme une substance intermediaire de la degradation des acides amines soufres. Son role dans la biosynthese de certains d'entre eux, problematique chez les mammiferes, est certain chez les oiseaux, qui, a cet egard, se comportent comme des autotrophes partiels, puisqu'ils reduisent le sulfate en sulfite. On s'apercoit ainsi qu'un degre d'evolution moindre confere au sulfite une importance metabolique plus grande. On peut s'attendre a trouver chez les vegetaux un role encore accru pour le sulfite. Le present travail entre dans ce cadre d'etudes comparees des transformations que peut subir un meme type de compose chimique: le sulfite, dans divers organismes appartenant a des especes ou a des regnes differents. Les donnees acquises exposees ici auront trait aux deux points suivants: I - La formation du sulfite dans les tissus vegetaux, II - L'oxydation dans ces tissus, du sulfite en sulfate. L'avoine nous a servi comme materiel de depart pour les experiences faites in vitro. Cette plante presente en effet l'avantage de se bien cultiver en toutes saisons, de se broyer facilement, et d'etre depourvue au maximum de mucilages, de resines, substances genantes pour l'analyse ulterieure. Les essais faits in vivo, ont mis en oeuvre des plants de tabac, qui permettent une nutrition par le petiole ou par la tige particulierement aisee.

  18. Mechanism of Selenite Removal by a Mixed Adsorbent Based on Fe–Mn Hydrous Oxides Studied Using X-ray Absorption Spectroscopy

    KAUST Repository

    Chubar, Natalia

    2014-11-18

    © 2014 American Chemical Society. Selenium cycling in the environment is greatly controlled by various minerals, including Mn and Fe hydrous oxides. At the same time, such hydrous oxides are the main inorganic ion exchangers suitable (on the basis of their chemical nature) to sorb (toxic) anions, separating them from water solutions. The mechanism of selenite adsorption by the new mixed adsorbent composed of a few (amorphous and crystalline) phases [maghemite, MnCO3, and X-ray amorphous Fe(III) and Mn(III) hydrous oxides] was studied by extended X-ray absorption fine structure (EXAFS) spectroscopy [supported by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) data]. The complexity of the porous adsorbent, especially the presence of the amorphous phases of Fe(III) and Mn(III) hydrous oxides, is the main reason for its high selenite removal performance demonstrated by batch and column adsorption studies shown in the previous work. Selenite was bound to the material via inner-sphere complexation (via oxygen) to the adsorption sites of the amorphous Fe(III) and Mn(III) oxides. This anion was attracted via bidentate binuclear corner-sharing coordination between SeO3 2- trigonal pyramids and both FeO6 and MnO6 octahedra; however, the adsorption sites of Fe(III) hydrous oxides played a leading role in selenite removal. The contribution of the adsorption sites of Mn(III) oxide increased as the pH decreased from 8 to 6. Because most minerals have a complex structure (they are seldom based on individual substances) of various crystallinity, this work is equally relevant to environmental science and environmental technology because it shows how various solid phases control cycling of chemical elements in the environment.

  19. Mechanism of Selenite Removal by a Mixed Adsorbent Based on Fe–Mn Hydrous Oxides Studied Using X-ray Absorption Spectroscopy

    KAUST Repository

    Chubar, Natalia; Gerda, Vasyl; Szlachta, Małgorzata

    2014-01-01

    © 2014 American Chemical Society. Selenium cycling in the environment is greatly controlled by various minerals, including Mn and Fe hydrous oxides. At the same time, such hydrous oxides are the main inorganic ion exchangers suitable (on the basis of their chemical nature) to sorb (toxic) anions, separating them from water solutions. The mechanism of selenite adsorption by the new mixed adsorbent composed of a few (amorphous and crystalline) phases [maghemite, MnCO3, and X-ray amorphous Fe(III) and Mn(III) hydrous oxides] was studied by extended X-ray absorption fine structure (EXAFS) spectroscopy [supported by Fourier transform infrared (FTIR) and X-ray diffraction (XRD) data]. The complexity of the porous adsorbent, especially the presence of the amorphous phases of Fe(III) and Mn(III) hydrous oxides, is the main reason for its high selenite removal performance demonstrated by batch and column adsorption studies shown in the previous work. Selenite was bound to the material via inner-sphere complexation (via oxygen) to the adsorption sites of the amorphous Fe(III) and Mn(III) oxides. This anion was attracted via bidentate binuclear corner-sharing coordination between SeO3 2- trigonal pyramids and both FeO6 and MnO6 octahedra; however, the adsorption sites of Fe(III) hydrous oxides played a leading role in selenite removal. The contribution of the adsorption sites of Mn(III) oxide increased as the pH decreased from 8 to 6. Because most minerals have a complex structure (they are seldom based on individual substances) of various crystallinity, this work is equally relevant to environmental science and environmental technology because it shows how various solid phases control cycling of chemical elements in the environment.

  20. Towards a selective adsorbent for arsenate and selenite in the presence of phosphate: Assessment of adsorption efficiency, mechanism, and binary separation factors of the chitosan-copper complex.

    Science.gov (United States)

    Yamani, Jamila S; Lounsbury, Amanda W; Zimmerman, Julie B

    2016-01-01

    The potential for a chitosan-copper polymer complex to select for the target contaminants in the presence of their respective competitive ions was evaluated by synthesizing chitosan-copper beads (CCB) for the treatment of (arsenate:phosphate), (selenite:phosphate), and (selenate:sulfate). Based on work by Rhazi et al., copper (II) binds to the amine moiety on the chitosan backbone as a monodentate complex (Type I) and as a bidentate complex crosslinking two polymer chains (Type II), depending on pH and copper loading. In general, the Type I complex exists alone; however, beyond threshold conditions of pH 5.5 during synthesis and a copper loading of 0.25 mol Cu(II)/mol chitosan monomer, the Type I and Type II complexes coexist. Subsequent chelation of this chitosan-copper ligand to oxyanions results in enhanced and selective adsorption of the target contaminants in complex matrices with high background ion concentrations. With differing affinities for arsenate, selenite, and phosphate, the Type I complex favors phosphate chelation while the Type II complex favors arsenate chelation due to electrostatic considerations and selenite chelation due to steric effects. No trend was exhibited for the selenate:sulfate system possibly due to the high Ksp of the corresponding copper salts. Binary separation factors, α12, were calculated for the arsenate-phosphate and selenite-phosphate systems, supporting the mechanistic hypothesis. While, further research is needed to develop a synthesis method for the independent formation of the Type II complexes to select for target contaminants in complex matrices, this work can provide initial steps in the development of a selective adsorbent. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Supplementation with Sodium Selenite and Selenium-Enriched Microalgae Biomass Show Varying Effects on Blood Enzymes Activities, Antioxidant Response, and Accumulation in Common Barbel (Barbus barbus)

    Czech Academy of Sciences Publication Activity Database

    Kouba, A.; Velíšek, J.; Stará, A.; Masojídek, Jiří; Kozák, P.

    2014-01-01

    Roč. 2014, Article ID 408270 (2014) ISSN 2314-6141 R&D Projects: GA ČR GA521/09/0656; GA MŠk ED2.1.00/03.0110; GA MŠk LO1205; GA MŠk ED2.1.00/01.0024 Grant - others:GA JU(CZ) 087/2013/Z Institutional support: RVO:61388971 Keywords : selenite * selenium * antioxidant response Subject RIV: EE - Microbiology, Virology

  2. Dynamic equilibrium of endogenous selenium nanoparticles in selenite-exposed cancer cells: a deep insight into the interaction between endogenous SeNPs and proteins.

    Science.gov (United States)

    Bao, Peng; Chen, Song-Can; Xiao, Ke-Qing

    2015-12-01

    Elemental selenium (Se) was recently found to exist as endogenous nanoparticles (i.e., SeNPs) in selenite-exposed cancer cells. By sequestrating critical intracellular proteins, SeNPs appear capable of giving rise to multiple cytotoxicity mechanisms including inhibition of glycolysis, glycolysis-dependent mitochondrial dysfunction, microtubule depolymerization and inhibition of autophagy. In this work, we reveal a dynamic equilibrium of endogenous SeNP assembly and disassembly in selenite-exposed H157 cells. Endogenous SeNPs are observed both in the cytoplasm and in organelles. There is an increase in endogenous SeNPs between 24 h and 36 h, and a decrease between 36 h and 72 h according to transmission electron microscopy results and UV-Vis measurements. These observations imply that elemental Se in SeNPs could be oxidized back into selenite by scavenging superoxide radicals and ultimately re-reduced into selenide; then the assembly and disassembly of SeNPs proceed simultaneously with the sequestration and release of SeNP high-affinity proteins. There is also a possibility that the reduction of elemental Se to selenide pathway may lie in selenite-exposed cancer cells, which results in the assembly and disassembly of endogenous SeNPs. Genome-wide expression analysis results show that endogenous SeNPs significantly altered the expression of 504 genes, compared to the control. The endogenous SeNPs induced mitochondrial impairment and decreasing of the annexin A2 level can lead to inhibition of cancer cell invasion and migration. This dynamic flux of endogenous SeNPs amplifies their cytotoxic potential in cancer cells, thus provide a starting point to design more efficient intracellular self-assembling systems for overcoming multidrug resistance.

  3. Effect of dietary supplementation with selenium-enriched yeast or sodium selenite on ruminal enzyme activities and blood chemistry in sheep

    Directory of Open Access Journals (Sweden)

    Zita Faixová

    2016-01-01

    Full Text Available The experiment was conducted to evaluate the effect of feeding a diet supplemented with different forms of selenium on the rumen fluid, blood and serum enzyme activity and osmotic fragility of red blood cells in sheep. The experiment was carried out on 18 sheep of the Valashka breed at the age of 18 months, divided into 3 groups. The first group was given basal diet (BD with a Se content of 0.17 mg/kg of dry matter (DM. The second group received BD supplemented with 0.4 mg Se/kg of (DM in the form of sodium selenite. The third group received BD supplemented with 0.4 mg Se/kg of (DM in the form of Se-yeast extract. Duration of the trial was 12 weeks. Selenium concentration in blood and total rumen fluid were elevated in both supplemented groups with the highest values in Se-yeast-treated sheep. Blood glutathione peroxidase (GPx activity was significantly increased, regardless of the source of selenium. Osmotic resistance of red blood cells was not affected by selenium supplementation. The results indicate that feeding a diet supplemented with selenium from Se-yeast or selenite improved selenium status in blood and total rumen fluid. Selenium from sodium selenite was as effective as selenium from Se-yeast in the availability of selenium for the blood GPx activity. The effect of selenium supplementation on the ruminal enzyme activity depends on the selenium form; GGT and GDH were significantly higher in the Se-yeast supplement group, AST and ALP were significantly higher in the selenite supplement group.

  4. Mortalite liee au VIH chez les enfants aux Chu campus et tokoin de ...

    African Journals Online (AJOL)

    Introduction. Le but de ce travail était d'étudier la mortalité liée au VIH chez les enfants séropositifs aux CHU-Campus et Tokoin de Lomé. Patients et méthode. Il s'est agi d'une étude prospective qui s'est déroulée dans les services de pédiatrie des CHU-Campus et Tokoin de Lomé et qui a couvert une période de 6 mois ...

  5. Grippe aviaire chez les oiseaux migrateurs : réseau régional de ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    La souche du virus de l'influenza aviaire hautement pathogène (H5N1) est responsable d'une forme grave de la maladie liée à une mortalité élevée chez la volaille d'élevage, les oiseaux d'eau et d'autres espèces d'oiseaux. Même si le mode de propagation de la maladie à l'échelle internationale est encore mal compris, ...

  6. Les dysthyroïdies chez l'hémodialysé chronique | Zbiti | Pan African ...

    African Journals Online (AJOL)

    Introduction: Les dysthyroïdies chez l'hémodialysé chronique sont représentées par une hypothyroïdie: dite le syndrome de basse T3, actuellement nommée "le syndrome de la maladie euthyroïdienne". L'objectif de notre travail est de déterminer le profil thyroïdien de nos HDC afin de préciser la prévalence des différents ...

  7. La systématique de l’esprit pratique chez Wolff, Kant, Fichte et Hegel

    OpenAIRE

    Siep, Ludwig

    2011-01-01

    En dépit des grands bouleversements systématiques dans la philosophie allemande du xviiie siècle, la continuité est étonnante, de Wolff à Hegel, pour ce qui concerne le contenu des doctrines sur la raison pratique. Une comparaison de ces doctrines chez Wolff, Kant, Fichte et Hegel peut révéler l’intention et les raisons pour lesquelles chacun de ces auteurs modifia la systématique des différentes facultés. À partir de Kant, autonomie et liberté deviennent les concepts directeurs permettant de...

  8. Étude des facteurs de risque du burnout chez les casques bleus ...

    African Journals Online (AJOL)

    Introduction: Il est devenu un problème de santé mentale au sein des casques bleus. L'objectif de cette étude était d'explorer les facteurs de risque du burnout chez les casques sénégalais en mission de maintien de la paix au Darfour. Méthode: Cette étude est transversale et analytique. Elle s'est déroulée du 19 avril au 20 ...

  9. Polymorphisme de l'APO A-IV chez les togolais: fréquences et ...

    African Journals Online (AJOL)

    Le polymorphisme génétique de l'apolipoprotéine A-IV (apo A-IV) a été étudié chez 601 togolais dont 252 sujets d'un isolat relatif, les Adélé et 349 sujets des ethnies, Ewé, Mina, Ouatchi originaires de la côte atlantique. La détermination des phénotypes a été réalisée par isoélectrofocalisation (IEF) sur gel de ...

  10. Répercussions socioéconomiques de la grippe aviaire chez les ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    La souche du virus de l'influenza aviaire hautement pathogène (H5N1) est responsable d'une forme grave de la maladie liée à une mortalité élevée chez la volaille d'élevage, les oiseaux d'eau et d'autres espèces d'oiseaux. Les autorités de la santé publique craignent une mutation de cette souche hautement virulente qui ...

  11. The effect of nano-selenium particles and sodium selenite on humoral immunity indices of quails using foods contaminated with aflatoxin B1

    Directory of Open Access Journals (Sweden)

    Ebrahim Talebi

    2017-08-01

    Full Text Available This experiment was conducted to evaluate the ability of inhibition of aflatoxin B1 by various sources of selenium and to compare the effect of nano selenium and sodium selenite on humoral immunity of quails. The experiment was performed in a completely randomized design (CRD using six treatments and four replicates of ten quail chicks per replicate. Two hundred forty quails were divided in six groups vis. control: without aflatoxin B1 and without selenium. Group2: 1ppm aflatoxin B1 and without selenium. Group3: 1 ppm aflatoxin B1 and 0.3 ppm nano selenium. Group4: 1 ppm aflatoxin B1 and 0.3 ppm sodium selenite. Group5: 1 ppm aflatoxin B1 and 0.6 ppm nano selenium. Group6: 1ppm aflatoxin B1 and 0.6 ppm sodium selenite. To evaluate the humoral immunity response 0.2­ml of sheep red blood cell (SRBC solution was injected into breast muscle of quails at day 35 and blood sampling was conducted after a week. Newcastle vaccine was injected at day 28 and the antibody titer was determined after two weeks. The highest level of titer of antibody against the SRBC solution was related to the group which received 0.06 ppm nano selenium (p

  12. The role of Cercospora zeae-maydis homologs of Rhodobacter sphaeroides 1O2-resistance genes in resistance to the photoactivated toxin cercosporin.

    Science.gov (United States)

    Beseli, Aydin; Goulart da Silva, Marilia; Daub, Margaret E

    2015-01-01

    The photosynthetic bacterium Rhodobacter sphaeroides and plant pathogenic fungus Cercospora nicotianae have been used as models for understanding resistance to singlet oxygen ((1)O(2)), a highly toxic reactive oxygen species. In Rhodobacter and Cercospora, (1)O(2) is derived, respectively, from photosynthesis and from the (1)O(2)-generating toxin cercosporin which the fungus produces to parasitize plants. We identified common genes recovered in transcriptome studies of putative (1)O(2)-resistance genes in these two systems, suggesting common (1)O(2)-resistance mechanisms. To determine if the Cercospora homologs of R. sphaeroides (1)O(2)-resistance genes are involved in resistance to cercosporin, we expressed the genes in the cercosporin-sensitive fungus Neurospora crassa and assayed for increases in cercosporin resistance. Neurospora crassa transformants expressing genes encoding aldo/keto reductase, succinyl-CoA ligase, O-acetylhomoserine (thiol) lyase, peptide methionine sulphoxide reductase and glutathione S-transferase did not have elevated levels of cercosporin resistance. Several transformants expressing aldehyde dehydrogenase were significantly more resistant to cercosporin. Expression of the transgene and enzyme activity did not correlate with resistance, however. We conclude that although the genes tested in this study are important in (1)O(2) resistance in R. sphaeroides, their Cercospora homologs are not involved in resistance to (1)O(2) generated from cercosporin. © FEMS 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  13. Increasing Selenium and Yellow Pigment Concentrations in Foxtail Millet (Setaria italica L.) Grain with Foliar Application of Selenite.

    Science.gov (United States)

    Ning, Na; Yuan, Xiang-Yang; Dong, Shu-Qi; Wen, Yin-Yuan; Gao, Zhen-Pan; Guo, Mei-Jun; Guo, Ping-Yi

    2016-03-01

    Although addition of selenium (Se) is known to increase Se in crops, it is unclear whether exogenous Se is linked to nutritional and functional components in foxtail millet (Setaria italica L.). In this study, we examined the potential of increasing Se and yellow pigment (YP) in foxtail millet grain by foliar application of Se. Field experiments were conducted during the growing season of foxtail millet in 2013 and 2014 to assess the effects of foliar spray of sodium selenite (10-210 g Se ha(-1)) on the yield, Se uptake and accumulation, total YP, and microminerals in the grain. Average grain yields with Se application were 5.60 and 4.53 t ha(-1) in the 2 years, showing no significant differences from the unfertilized control. However, grain Se concentration increased linearly with Se application rate, by 8.92 and 6.09 μg kg(-1) in the 2 years with application of 1 g Se ha(-1) (maximum grain recovery rates of Se fertilizer, 52 and 28 %). Likewise, total grain YP concentration markedly increased by 0.038 and 0.031 mg kg(-1) in the 2 years with application of 1 g Se ha(-1). Grain Mn, Cu, Fe, and Zn concentrations were not significantly affected by Se application. This study indicated that foliar application of Se effectively and reliably increased the concentrations of Se and YP in foxtail millet grain without affecting the yield or mineral micronutrient concentrations. Thus, foliar-applied selenite has a significant potential to increase the concentrations of selenium and YP (putative lutein (Shen, J Cereal Sci 61:86-93, 2015; Abdel-Aal, Cereal Chem 79:455-457, 2002; Abdel-Aal, J Agric Food Chem 55:787-794, 2007)) of foxtail millet and, thus, the health benefits of this crop.

  14. Role of pirenoxine in the effects of catalin on in vitro ultraviolet-induced lens protein turbidity and selenite-induced cataractogenesis in vivo.

    Science.gov (United States)

    Hu, Chao-Chien; Liao, Jiahn-Haur; Hsu, Kuang-Yang; Lin, I-Lin; Tsai, Ming-Hsuan; Wu, Wen-Hsin; Wei, Tzu-Tang; Huang, Yi-Shiang; Chiu, Shih-Jiuan; Chen, Hsiang-Yin; Wu, Shih-Hsiung; Wu, Tzu-Hua

    2011-01-01

    In this study, we investigated the biochemical pharmacology of pirenoxine (PRX) and catalin under in vitro selenite/calcium- and ultraviolet (UV)-induced lens protein turbidity challenges. The systemic effects of catalin were determined using a selenite-induced cataractogenesis rat model. In vitro cataractogenesis assay systems (including UVB/C photo-oxidation of lens crystallins, calpain-induced proteolysis, and selenite/calcium-induced turbidity of lens crystallin solutions) were used to screen the activity of PRX and catalin eye drop solutions. Turbidity was identified as the optical density measured using spectroscopy at 405 nm. We also determined the in vivo effects of catalin on cataract severity in a selenite-induced cataract rat model. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was applied to analyze the integrity of crystallin samples. PRX at 1,000 μM significantly delayed UVC-induced turbidity formation compared to controls after 4 h of UVC exposure (pturbidity induced by 4 h of UVC exposure was ameliorated in the presence of catalin equivalent to 1~100 μM PRX in a concentration-dependent manner. Samples with catalin-formulated vehicle only (CataV) and those containing PRX equivalent to 100 μM had a similar protective effect after 4 h of UVC exposure compared to the controls (pturbidity formation compared to controls on days 0~4 (pturbidity on day 1 (pturbidity but required millimolar levels to protect against UVC irradiation. The observed inhibition of UVC-induced turbidity of lens crystallins by catalin at micromolar concentrations may have been a result of the catalin-formulated vehicle. Transient protection by catalin against selenite-induced turbidity of crystallin solutions in vitro was supported by the ameliorated cataract scores in the early stage of cataractogenesis in vivo by subcutaneously administered catalin. PRX could not inhibit calpain-induced proteolysis activated by calcium or catalin itself, and may be

  15. Luxation postérieure de l'épaule chez un sujet sportif traitée par ...

    African Journals Online (AJOL)

    Luxation postérieure de l'épaule chez un sujet sportif traitée par transfert pédiculé du sub-scapulaire. Adil El Alaoui, Ilyas Rabhi, Aliou Bah, Mouhcine Sbiyaa, Amine Mezzani, Badr Alami, Amine Marzouki, Fawzi Boutayeb ...

  16. Préoccupations de carrière chez les médecins de travail des ...

    African Journals Online (AJOL)

    Préoccupations de carrière chez les médecins de travail des groupements de Médecine de travail en Tunisie. Irtyah Merchaoui, Asma Chouchène, Ines Bouanène, Néila Chaari, Wassim Zrafi, Adnène Henchi, Mohamed Akrout, Charfeddine Amri ...

  17. Sodium selenite/selenium nanoparticles (SeNPs) protect cardiomyoblasts and zebrafish embryos against ethanol induced oxidative stress.

    Science.gov (United States)

    Kalishwaralal, Kalimuthu; Jeyabharathi, Subhaschandrabose; Sundar, Krishnan; Muthukumaran, Azhaguchamy

    2015-10-01

    Alcoholic cardiomyopathy is the damage caused to the heart muscles due to high level of alcohol consumption resulting in enlargement and inflammation of the heart. Selenium is an important trace element that is beneficial to human health. Selenium protects the cells by preventing the formation of free radicals in the body. In the present study, protein mediated synthesis of SeNPs was investigated. Two different sizes of SeNPs were synthesized using BSA and keratin. The synthesized SeNPs were characterized by scanning electron microscopy (SEM) with elemental composition analysis Energy Dispersive X-ray spectroscopy(EDX) and X-ray diffraction (XRD). This study demonstrates the in vitro and in vivo antioxidative effects of sodium selenite and SeNPs. Further selenium and SeNPs were evaluated for their ability to protect against 1% ethanol induced oxidative stress in H9C2 cell line. The selenium and SeNPs were found to reduce the 1% ethanol-induced oxidative damage through scavenging intracellular reactive oxygen species. The selenium and SeNPs could also prevent pericardial edema induced ethanol treatment and reduced apoptosis and cell death in zebrafish embryos. The results indicate that selenium and SeNPs could potentially be used as an additive in alcoholic beverage industry to control the cardiomyopathy. Copyright © 2015 Elsevier GmbH. All rights reserved.

  18. Puzzolanic cements of greater resistance at the attack of selenitic waters than the high sulfate resistance portland cements, and viceverse

    Directory of Open Access Journals (Sweden)

    Talero, Rafael

    1987-09-01

    Full Text Available This work confirms the certainty of the predictions of useful service given by Kaluosek and al. for the sulphate resistant portland cements (type V, USA, subject to severe selenitic attack. Two sulphate resistant portland cements, were tested by means of the Le Chatelier Anstett method. The tarts were destroyed at ages of three years, having detected in them the presence of thaumasite by XRD. Even so, the impossibility and possibility thaumasite formation was confirmed in pozzolanic cements tarts, which either had or did not have adequate amount of pozzolana (diatomite for such purpose.

    Este trabajo confirman las predicciones de vida útil dadas por Kalousek y colaboradores, para los cementos portland de elevada resistencia al ataque de los iones sulfato (tipo V, USA, sometidos a un severo ataque selenitoso. Se ensayaron dos cementos portland de elevada resistencia al ataque del yeso, mediante el ensayo de Le Chatelier-Anstett. Sus tortas correspondientes se destruyeron a la edad de tres años, habiéndose detectado en las mismas la presencia de thaumasita por DRX. Asimismo se confirmó la imposibilidad y posibilidad de formación de thaumasita en tortas de cementos puzolánicos, los cuales tenían, o no, respectivamente, una adecuada cantidad de puzolana (diatomita para tales fines.

  19. La fibroscopie digestive haute chez 2795 patients au centre hospitalier universitaire-campus de Lomé: les particularités selon le sexe

    Science.gov (United States)

    Lawson-Ananissoh, Laté Mawuli; Bouglouga, Oumboma; Bagny, Aklesso; Kaaga, Laconi; Redah, Datouda

    2014-01-01

    Introduction Notre étude consistera à rapporter les indications et les lésions objectivées à la fibroscopie digestive haute et relever les particularités selon le sexe. Méthodes Étude rétrospective, descriptive sur des résultats de compte-rendu de la fibroscopie digestive haute menée en unité d'endoscopie digestive du service d'hépato-gastro-entérologie du CHU Campus de Lomé du 15 Mai 2009 au 31 Décembre 2013. Résultats La fibroscopie digestive haute a été réalisée chez 2795 patients dont 1188 hommes et 1607 femmes. L’âge moyen était de 40,65 ans (Extrêmes: 5 et 93 ans). La fibroscopie digestive haute était normale chez les femmes que chez les hommes avec une différence statistiquement significative (p = 0,000). Les principales indications étaient: les épigastralgies chez les femmes (p = 0,000); les hémorragies digestives hautes (p = 0,000) et l'hypertension portale (p = 0,000) chez les hommes; 3485 lésions pathologiques ont été observées. La pathologie inflammatoire prédominait (56,3%), la pathologie ulcéreuse (13,89%), la pathologie tumorale (2,01%). Les varices et la candidose œsophagiennes étaient significativement notées chez les hommes. Les ulcérations gastriques (p = 0,000), le reflux biliaire duodéno-gastrique (p = 0,017) étaient plus retrouvés chez les femmes et la gastropathie hypertensive beaucoup plus chez les hommes (p = 0,000). Que les lésions duodénales soient inflammatoires ou ulcéreuses associées ou non à une sténose bulbaire, elles étaient plus fréquentes chez les hommes. Conclusion De manière générale, il y avait une prédominance des lésions inflammatoires chez les femmes, les lésions tumorales et ulcéreuses chez les hommes PMID:25852805

  20. L’hybridation interspécifique chez les champignons phytopathogènes à l’origine de nouvelles maladies

    OpenAIRE

    Frey, Pascal

    2009-01-01

    Mécanisme évolutif bien connu chez les plantes, l’hybridation interspécifique a été relativement peu étudiée dans certains groupes taxonomiques, comme les champignons. Chez les champignons phytopathogènes, l’hybridation entre une espèce indigène et une espèce exotique peut pourtant conduire à l’émergence de nouvelles maladies des plantes.

  1. Facteurs prédictifs de la réponse à la CERA chez les hémodialysés ...

    African Journals Online (AJOL)

    Facteurs prédictifs de la réponse à la CERA chez les hémodialysés chroniques naïfs de traitement par agent stimulant l'érythropoïèse. ... Il s'agit une étude prospective mono centrique faite au sein d'une population d' hémodialysés chroniques. ... L'anémie est une complication majeure chez les hémodialysés chroniques.

  2. Doppler transcranien au cours de la drépanocytose chez l'enfant Malagasy

    Science.gov (United States)

    Herinirina, Nicolas Fanantenana; Rajaonarison, Lova Hasina Ny Ony Narindra; Herijoelison, Andry Roussel; Rakoto, Olivat Aimée Alson; Ahmad, Ahmad

    2016-01-01

    Introduction Le doppler transcrânien est un outil efficace permettant de dépister les enfants drépanocytaires à risque d'AVC. Méthodes Nous avons réalisé une étude descriptive transversale sur des enfants Malagasy âgés entre 24 mois et 15 ans (groupe 1: 57 drépanocytaires, groupe 2: 43 témoins) afin d’évaluer le profil vélocimétrique des artères cérébrales chez les drépanocytaires. Un examen Doppler transcrânien a été réalisé avec étude des flux sanguins cérébraux chez les enfants des deux groupes. Résultats Pour les sujets drépanocytaires, la vitesse moyenne (VM) de l'artère cérébrale moyenne était de 100,9 ± 26,8 cm/s, l'indice de pulsatilité (IP) de 0,73 ± 0,20, la différence entre les artères cérébrales moyennes droite et gauche (ACMr) de 19,8 ± 21,5 cm/s, le rapport des vitesses de l'artère cérébrale antérieure/artère cérébrale moyenne (ACA/ACM) de 0,7 ± 0,2. Pour les enfants non drépanocytaires, VM: 80,6 ± 19,3 cm/s, IP: 0,79 ± 0,14, ACMr: 17 ± 20,1 cm/s, ACA/ACM: 0,8 ± 0,2. La vélocité des enfants drépanocytaires était supérieure au groupe contrôle. Les vitesses ont été corrélées avec le taux d'hémoglobine et l’âge et non pas avec le sexe et le volume globulaire moyen. Conclusion Les vitesses circulatoires cérébrales sont élevées chez les drépanocytaires que les enfants non drépanocytaires et sont influencées par le taux d'hémoglobine et l’âge. PMID:27516829

  3. Crystallization and preliminary crystallographic studies of FoxE from Rhodobacter ferrooxidans SW2, an FeII oxidoreductase involved in photoferrotrophy

    International Nuclear Information System (INIS)

    Pereira, L.; Saraiva, I. H.; Coelho, R.; Newman, D. K.; Louro, R. O.; Frazão, C.

    2012-01-01

    Crystals of the R. ferrooxidans SW2 iron oxidoreductase FoxE were obtained and the phase problem was solved by Fe SAD at 2.44 Å resolution. FoxE is a protein encoded by the foxEYZ operon of Rhodobacter ferrooxidans SW2 that is involved in Fe II -based anoxygenic photosynthesis (‘photoferrotrophy’). It is thought to reside in the periplasm, where it stimulates light-dependent Fe II oxidation. It contains 259 residues, including two haem c-binding motifs. As no three-dimensional model is available and there is no structure with a similar sequence, crystals of FoxE were produced. They diffracted to 2.44 Å resolution using synchrotron radiation at the Fe edge. The phase problem was solved by SAD using SHELXC/D/E and the experimental maps confirmed the presence of two haems per molecule

  4. Correlation of paramagnetic states and molecular structure in bacterial photosynthetic reaction centers: The symmetry of the primary electron donor in Rhodopseudomonas viridis and Rhodobacter sphaeroides R-26

    International Nuclear Information System (INIS)

    Norris, J.R.; Budil, D.E.; Gast, P.; Chang, C.H.; El-Kabbani, O.; Schiffer, M.

    1989-01-01

    The orientation of the principal axes of the primary electron donor triplet state measured in single crystals of photosynthetic reaction centers is compared to the x-ray structures of the bacteria Rhodobacter (Rb.) sphaeroides R-26 and Rhodopseudomonas (Rps.) viridis. The primary donor of Rps. viridis is significantly different from that of Rb. sphaeroides. The measured directions of the axes indicate that triplet excitation is almost completely localized on the L-subunit half of the dimer in Rps. viridis but is more symmetrically distributed on the dimeric donor in Rb. sphaeroides R-26. The large reduction of the zero field splitting parameters relative to monomeric bacteriochlorophyll triplet in vitro suggests significant participation of asymmetrical charge transfer electronic configurations in the special pair triplet state of both organisms

  5. ZINC ET PROFIL IMMUNO-INFLAMMATOIRE CHEZ LES ENFANTS ET LES ADOLESCENTS DIABETIQUES DE TYPE 1

    OpenAIRE

    BESTAOUI, Abdelaziz

    2014-01-01

    Introduction : le diabète de type 1 (DT1) est une maladie autoimmune qui résulte de la destruction progressive et sélective des cellules-bêta pancréatiques. Objectifs : Ce travail consiste à déterminer les nivaux de zinc apporté par l’alimentation et de mesurer sa concentration sérique chez les diabétiques de type 1 et les sujets sains, contrôles. But : Montrer le rôle immuno-modulateur du zinc dans le processus d’auto-immunité inflammatoire au cours de DT1. Matériels et méthodes : t...

  6. Développement folliculaire ovarien et ovulation chez les mammifères

    OpenAIRE

    Monniaux , Danielle; Caraty , Alain; Clement , Frederique; Dalbiès-Tran , Rozenn; Dupont , J.; Fabre , Stéphane; Gérard , N.; Mermillod , Pascal; Monget , Philippe; Uzbekova , Svetlana

    2009-01-01

    Cette revue présente l’état des connaissances sur la folliculogenèse et l’ovulation chez les mammifères. La folliculogenèse basale est une phase de croissance folliculaire lente, au cours de laquelle l’ovocyte acquiert la compétence méiotique. La folliculogenèse terminale est une phase de développement rapide, au cours de laquelle le follicule ovulatoire est sélectionné et termine sa maturation, tandis que l’ovocyte acquiert la compétence au développement. La revue décrit les différents chang...

  7. Hallucination chez Flaubert : poétique de la perception

    Directory of Open Access Journals (Sweden)

    Tomoko Hashimoto

    2009-01-01

    Full Text Available Notre étude vise à montrer dans le cadre d’une poétique du discours réaliste la manière dont l’« hallucination » fonctionne, se construit et trouve sa signification chez Flaubert. Par quels procédés fait-il surgir des mots le caractère éphémère des images et l’intensité de leur perception ?Notre étude se développera en une forme de triptyque, où le contexte, l’avant-texte et le texte seront examinés. Mais, ces trois points constituant ensemble l’œuvre de Flaubert, nous ne les séparerons pas à...

  8. La digestion chez les camélidés ; comparaison avec les ruminants

    OpenAIRE

    Jouany, J Pierre

    2000-01-01

    Les études sur la digestion et le métabolisme des camélidés ont bénéficié au cours des quinze dernières années des progrès techniques et méthodologiques issus des travaux conduits chez les ruminants. On dispose aujourd’hui d’éléments scientifiques fiables qui permettent de comparer les aptitudes digestives et métaboliques respectives de ces deux types d’animaux. L’anatomie des pré-estomacs ainsi que le comportement alimentaire des animaux sont très différents entre camélidés et ruminants. De ...

  9. Effect of pH on optimization of photofermentative hydrogen production by co-culture of Rhodobacter sphaeroides-NMBL-02 and Bacillus firmus-NMBL-03.

    Science.gov (United States)

    Pandey, A; Dolly, S; Semwal, D; Pandey, A

    2017-07-31

    Rhodobacter sphaeroides NMBL-02, photosynthetic purple non sulfur (PNS) bacteria and associated Bacillus firmus NMBL-03 were isolated from water sample collected from 15-20 inches beneath the surface of ponds from Northern region of India in modified Sistrom's media (120 ml) containing 3 g/L malate and 1.2 g/L ammonium sulfate. The isolation was done in air tight serum bottles (120 ml) under tungsten bulb (1.8 kLux light intensity) at 30 oC ± 2 oC. The PNS and heterotrophic bacteria associated with the culture was purified by clonal selection method and characterized by 16S rDNA sequencing. The PNS isolate was identified as Rhodobacter sphaeroides NMBL-02 (ID: 1467407, Accession BANKIT: JN256030) and associated heterotroph as Bacillus firmus NMBL-03 (Gene Bank Accession no.: JN 256029). The effect of initial medium pH on optimization of hydrogen production was investigated in batch process. The maximum hydrogen potential and hydrogen production rate was 2310 ± 55 ml/L and 4.75 ml/L culture/h respectively using glutamate (1.7 mmol/L) as nitrogen source and malate (22.38 mmol/L) as carbon source with 76.39% malate conversion efficiency at initial medium pH 5.0. This co-culture has the ability to produce significant amount of hydrogen in the pH range of 5.0 to 10.0 with 76.39% to 35.71% malate conversion respectively.

  10. A comparison of the uptake of [75Se]Selenite [75Se] Selenomethionine and [35S]methionine by the tissues of ewes and lambs

    International Nuclear Information System (INIS)

    Fuss, C.N.; Godwin, K.O.

    1975-01-01

    The fate of selenium, given as Na 2 75 SeO 3 , or [ 75 Se] selenomethionine, and of [ 35 S]methionine administered intravenously to ewes and lambs, has been examined. The main intention was to follow the incorporation of selenium into protein in a number of tissues, including liver and kidney, and to measure the extent of that incorporation of selenoamino acid, particularly with respect to the administration of selenite. The ewes chosen were lactating ewes with lambs at foot, and the lambs were animals which had been weaned on to fodder low in selenium and were recovering from white muscle disease with selenium therapy. These two experimental situations were chosen as they offered conditions under which selenium incorporation might be considered to be maximal. Entry of isotope into milk was rapid and was greater when 75 Se was given as the selenoamino acid than as selenite. In both ewes and lambs greater amounts of activity, derived from selenite, were bound to plasma proteins than to the proteins of milk. This was particularly evident in samples taken some hours after administration. This ability of the plasma to bind selenium was demonstrated by alkaline dialysis. Small, though significant amounts of selenium, derived from Na 2 75 SeO 3 , were incorporated as selenoamino acids into the proteins of liver, kidney and pancreas, as well as into the proteins of milk and plasma. In ewes, both selenomethionine and selenocystine were identified chromatographically in enzyme digests of defatted liver and kidney. Some differences occurred in the distribution of labelled compounds in organs from lactating ewes and recovering lambs. The incorporation of selenium into protein is discussed briefly in relation to the recent findings of an association between selenium and the enzyme glutathione peroxidase. (author)

  11. Les Cicatrices Retractiles Post-Brulures Du Membre Inferieur Chez L’Enfant

    Science.gov (United States)

    Sankale, A.A.; Manyacka Ma Nyemb, P.; Coulibaly, N.F.; Ndiaye, A.; Ndoye, M.

    2010-01-01

    Summary Il s'agit d'une étude faisant ressortir les aspects épidémiologiques, cliniques et thérapeutiques des séquelles de brûlures du membre inférieur chez l'enfant, à propos de 42 cas colligés au service de chirurgie infantile de l'Hôpital Aristide Le Dantec (Sénégal). L'âge moyen retrouvé est de 5 ans et 3 mois, et le sex-ratio garçons/filles de 1,8/1. La brûlure thermique est causée par une flamme dans 33% des cas, par un liquide chaud dans 21% des cas, et par des braises dans 21% des cas. Les cicatrices rétractiles intéressent le genou et le creux poplité dans 47% des cas et le pied dans 45% des cas. Elles sont bilatérales dans 21% des cas, et concernent une autre localisation associée dans 21% des cas. Quant aux brides, 21% ont bénéficié d'une chirurgie, avec un délai moyen de 3 ans et 2 mois après la brûlure. Cette procédure chirurgicale consiste en une plastie en Z dans 91% des cas, à laquelle est associée une greffe de peau dans 54% des cas. Une rééducation fonctionnelle est pratiquée chez 54% des opérés. Parallèlement aux données de la littérature, nos résultats montrent que l'optimisation de la prise en charge passe par une meilleure prévention des accidents domestiques et une bonne codification thérapeutique. PMID:21991202

  12. Prise en charge de l’infection gonococcique chez les adultes et les jeunes

    Science.gov (United States)

    Pogany, Lisa; Romanowski, Barbara; Robinson, Joan; Gale-Rowe, Margaret; Latham-Carmanico, Cathy; Weir, Christine; Wong, Tom

    2015-01-01

    Résumé Objectif Présenter des recommandations sur la prise en charge de l’infection gonococcique chez les adultes et les jeunes. Qualité des données Les recommandations thérapeutiques des lignes directrices canadiennes sur les infections transmissibles sexuellement reposent sur une recherche documentaire de même que sur des catégories de recommandations et des niveaux de qualité de données déterminés par au moins 2 évaluateurs. Les recommandations ont été revues par des pairs et sont en instance d’approbation par le groupe de travail d’experts. Message principal Les nouvelles recommandations portant sur la prise en charge de l’infection gonococcique chez les adultes et les jeunes préconisent les cultures à titre d’outil diagnostique lorsqu’elles sont pratiques, le traitement par antibiothérapie combinée (ceftriaxone associée à l’azithromycine) et le signalement sans délai de tous les cas dont le traitement a échoué aux autorités de santé publique. Conclusion Si elles sont suivies, ces nouvelles recommandations pourraient réduire l’échec thérapeutique, contribuer à une surveillance plus étroite des tendances à la résistance de Neisseria gonorrhoeae aux antibiotiques et contribuer à prévenir la transmission de gonorrhée résistante à plusieurs médicaments.

  13. Selenium Accumulation Characteristics and Biofortification Potentiality in Turnip (Brassica rapa var. rapa Supplied with Selenite or Selenate

    Directory of Open Access Journals (Sweden)

    Xiong Li

    2018-01-01

    Full Text Available Selenium (Se is an essential trace element for humans. About 70% of the regions in China, including most of the Tibetan Plateau, are faced with Se deficiency problems. Turnip is mainly distributed around the Tibetan Plateau and is one of the few local crops. In the present study, we compared the absorption and translocation differences of Se (IV selenite and Se (VI selenate in turnip. The results showed that Se treatment, either by soil addition (0.2–2 mg Se kg−1 dry soil or by foliar spraying (50–200 mg L−1 Se, could significantly increase the Se concentrations in turnips, and 0.5 mg Se (IV or Se (VI kg−1 dry matter in soils could improve the biomasses of turnips. Moreover, turnip absorbed significantly more Se (VI than Se (IV at the same concentration and also transferred much more Se (VI from roots to leaves. Based on the Se concentrations, as well as the bioconcentration factors and translocation coefficients, we considered that turnip might be a potential Se indicator plant. Subsequently, we estimated the daily Se intake for adults based on the Se concentrations in turnip roots. The results indicated that Se (IV should be more suitable as an artificial Se fertilizer for turnips, although the levels found in most samples in this study could cause selenosis to humans. In addition, we also estimated the optimum and maximum Se concentrations for treating turnips based on the linear relations between Se concentrations in turnip roots and Se treatment concentrations. The results provided preliminary and useful information about Se biofortification in turnips.

  14. Selenite reduction by anaerobic microbial aggregates: Microbial community structure, and proteins associated to the produced selenium spheres.

    Directory of Open Access Journals (Sweden)

    Graciela eGonzalez-Gil

    2016-04-01

    Full Text Available Certain types of anaerobic granular sludge, which consists of microbial aggregates, can reduce selenium oxyanions. To envisage strategies for removing those oxyanions from wastewater and recovering the produced elemental selenium (Se0, insights into the microbial community structure and synthesis of Se0 within these microbial aggregates are required. High-throughput sequencing showed that Veillonellaceae (c.a. 20 % and Pseudomonadaceae (c.a.10 % were the most abundant microbial phylotypes in selenite reducing microbial aggregates. The majority of the Pseudomonadaceae sequences were affiliated to the genus Pseudomonas. A distinct outer layer (~200 m of selenium deposits indicated that bioreduction occurred in the outer zone of the microbial aggregates. In that outer layer, SEM analysis showed abundant intracellular and extracellular Se0 (nano spheres, with some cells having high numbers of intracellular Se0 spheres. Electron tomography showed that microbial cells can harbor a single large intracellular sphere that stretches the cell body. The Se0 spheres produced by the microorganisms were capped with organic material. X-ray photoelectron spectroscopy (XPS analysis of extracted Se0 spheres, combined with a mathematical approach to analyzing XPS spectra from biological origin, indicated that proteins and lipids were components of the capping material associated to the Se0 spheres. The most abundant proteins associated to the spheres were identified by proteomic analysis. Most of the proteins or peptide sequences capping the Se0 spheres were identified as periplasmic outer membrane porins and as the cytoplasmic elongation factor Tu protein, suggesting an intracellular formation of the Se0 spheres. In view of these and previous findings, a schematic model for the synthesis of Se0 spheres by the microorganisms inhabiting the granular sludge is proposed.

  15. Removal mechanism of selenite by Fe{sub 3}O{sub 4}-precipitated mesoporous magnetic carbon microspheres

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Jianwei; Fu, Fenglian, E-mail: fufenglian2006@163.com; Ding, Zecong; Li, Na; Tang, Bing

    2017-05-15

    Highlights: • MCMSs were prepared via green hydrothermal carbonization and coprecipitation. • MCMSs displayed effective removal of Se(IV) from wastewater. • Se(IV) formed inner-sphere complexes with MCMSs and was reduced to insoluble Se{sup 0}. • MCMSs can be easily separated and recycled by an external magnetic field. - Abstract: A mesoporous composite of magnetic carbon microspheres (MCMSs) was synthesized via introducing Fe{sub 3}O{sub 4} nanoscale particles to the surface of carbon microspheres (CMSs) by coprecipitation. Scanning electron microscopy and transmission electron microscopy showed the Fe{sub 3}O{sub 4} nanoscale particles were dispersedly immobilized on the surface of CMSs. The MCMSs demonstrated effective removal of selenite (Se(IV)) from wastewater. MCMSs showed the regular pattern where the lower pH value, the lower residual Se(IV) concentration. The coexisting sulfate, nitrate, chloride, carbonate, and silicate had no significant effect on Se(IV) removal, whereas phosphate hindered the removal of Se(IV) by competing with Se(IV) and formed inner–sphere complexes with Fe{sub 3}O{sub 4} on the surface of MCMSs. Through X–ray photoelectron spectroscopy analysis, Se(IV) can not only form inner–sphere complexes with MCMSs, but also be reduced to insoluble elemental selenium (Se{sup 0}) by Fe{sub 3}O{sub 4} which was oxidized and formed γ–Fe{sub 2}O{sub 3}. Moreover, the superparamagnetic MCMSs can be easily separated from solution by means of an external magnetic field. The high removal efficiency for Se(IV) and rapid separability of MCMSs made them promising materials for the application in the practice.

  16. Effect of sodium selenite on chosen anti- and pro-oxidative parameters in rats treated with lithium: A pilot study.

    Science.gov (United States)

    Musik, Irena; Kocot, Joanna; Kiełczykowska, Małgorzata

    2015-06-01

    Selenium is an essential element of antioxidant properties. Lithium is widely used in medicine but its administration can cause numerous side effects including oxidative stress. The present study aimed at evaluating if sodium selenite could influence chosen anti- and pro-oxidant parameters in rats treated with lithium. The experiment was performed on four groups of Wistar rats: I (control) - treated with saline; II (Li) - treated with lithium (2.7 mgLi/kg b.w. as Li2CO3), III (Se) - treated with selenium (0.5 mgSe/kg b.w. as Na2SeO3), IV (Li+Se) - treated with Li2CO3 and Na2SeO3 together at the same doses as in group II and III, respectively. All treatments were performed by stomach tube for three weeks in form of water solutions. The following anti- and pro-oxidant parameters: total antioxidant status (TAS) value, catalase (CAT) activity, concentrations of ascorbic acid (AA) and malonyldialdehyde (MDA) in plasma as well as whole blood superoxide dismutase (SOD) and glutathione peroxidase (GPx) activities were measured. Selenium given alone markedly enhanced whole blood GPx and diminished plasma CAT vs. Lithium significantly decreased plasma CAT and slightly increased AA vs. Selenium co-administration restored these parameters to the values observed in control animals. Furthermore, selenium co-administration significantly increased GPx in Li-treated rats. All other parameters (TAS, SOD and MDA) were not affected by lithium and/or selenium. Further research seems to be warranted to decide if application of selenium as an adjuvant in lithium therapy is worth considering. Copyright © 2014 Institute of Pharmacology, Polish Academy of Sciences. Published by Elsevier Urban & Partner Sp. z o.o. All rights reserved.

  17. Selenite Reduction by Anaerobic Microbial Aggregates: Microbial Community Structure, and Proteins Associated to the Produced Selenium Spheres

    KAUST Repository

    Gonzalez-Gil, Graciela

    2016-04-26

    Certain types of anaerobic granular sludge, which consists of microbial aggregates, can reduce selenium oxyanions. To envisage strategies for removing those oxyanions from wastewater and recovering the produced elemental selenium (Se0), insights into the microbial community structure and synthesis of Se0 within these microbial aggregates are required. High-throughput sequencing showed that Veillonellaceae (c.a. 20%) and Pseudomonadaceae (c.a.10%) were the most abundant microbial phylotypes in selenite reducing microbial aggregates. The majority of the Pseudomonadaceae sequences were affiliated to the genus Pseudomonas. A distinct outer layer (∼200 μm) of selenium deposits indicated that bioreduction occurred in the outer zone of the microbial aggregates. In that outer layer, SEM analysis showed abundant intracellular and extracellular Se0 (nano)spheres, with some cells having high numbers of intracellular Se0 spheres. Electron tomography showed that microbial cells can harbor a single large intracellular sphere that stretches the cell body. The Se0 spheres produced by the microorganisms were capped with organic material. X-ray photoelectron spectroscopy (XPS) analysis of extracted Se0 spheres, combined with a mathematical approach to analyzing XPS spectra from biological origin, indicated that proteins and lipids were components of the capping material associated to the Se0 spheres. The most abundant proteins associated to the spheres were identified by proteomic analysis. Most of the proteins or peptide sequences capping the Se0 spheres were identified as periplasmic outer membrane porins and as the cytoplasmic elongation factor Tu protein, suggesting an intracellular formation of the Se0 spheres. In view of these and previous findings, a schematic model for the synthesis of Se0 spheres by the microorganisms inhabiting the granular sludge is proposed.

  18. Ethylenediammonium dication: H-bonded complexes with terephthalate, chloroacetate, phosphite, selenite and sulfamate anions. Detailed vibrational spectroscopic and theoretical studies of ethylenediammonium terephthalate

    Science.gov (United States)

    Marchewka, M. K.; Drozd, M.

    2012-12-01

    Crystalline complexes between ethylenediammonium dication and terephthalate, chloroacetate, phosphite, selenite and sulfamate anions were obtained by slow evaporation from water solution method. Room temperature powder infrared and Raman measurements were carried out. For ethylenediammonium terephthalate theoretical calculations of structure were performed by two ways: ab-initio HF and semiempirical PM3. In this case the PM3 method gave more accurate structure (closer to X-ray results). The additional PM3 calculations of vibrational spectra were performed. On the basis theoretical approach and earlier vibrational studies of similar compounds the vibrational assignments for observed bands have been proposed. All compounds were checked for second harmonic generation (SHG).

  19. L’hybridation interspécifique et l’hétérosis chez les arbres forestiers

    OpenAIRE

    Pâques E., Luc

    2011-01-01

    L’hybridation interspécifique se rencontre fréquemment chez les arbres forestiers et intéressent les chercheurs dans des contextes très différents : introgression dans les aires naturelles des espèces, pollution des pools génétiques autochtones par des espèces/variétés introduites…. Elle est aussi valorisée en amélioration génétique en vue de la création variétale. Ce dernier aspect constitue le cœur de nos activités et de notre projet de recherche. Etudiés depuis longtemps chez les plantes...

  20. Sarcome à cellules claires du rein : À propos d’un cas chez un jeune de 17 ans

    Science.gov (United States)

    Mazdar, Adil; Sakel, Adil Ait; Essatara, Younes; Beddouche, Ali; Elsayegh, Hachem; Iken, Ali; Benslimane, Lounis; Nouini, Yassine

    2014-01-01

    Résumé Le sarcome à cellules claires du rein (SCCR) se voit très rarement chez les jeunes. Il est caractérisé par une évolution agressive marquée par un taux élevé de récidive et de mortalité. Nous rapportons le cas d’un SCCR chez un patient de 17 ans et nous discutons de son apport et de son intérêt médical en vue d’une bonne prise en charge thérapeutique. L’agressivité du SCCR et la prolifération de métastases surtout osseuses impliquent qu’il ne faut pas méconnaître ce diagnostic afin de mettre en place un traitement adapté. PMID:24940474

  1. Urètrocèle post-traumatique chez l'homme: A propos de 2 cas

    African Journals Online (AJOL)

    Y. Sow

    d'épithélium et de couche musculaire lisse [2]. Il peut être secon- daire à une effraction de la paroi urétrale par un traumatisme pelvien ou périnéal [1] (c'est le cas de nos observations) ou à un traumatisme iatrogène: sondage vésical prolongé surtout chez les paraplégiques ou traumatique, urètrotomie endoscopique [3].

  2. De la ferme à la fourchette – lutte contre l'obésité chez les enfants ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    26 avr. 2016 ... ... but de combattre l'obésité chez les enfants. La démarche repose sur trois piliers, à savoir augmenter la proportion de fruits et de légumes frais dans les repas servis à l'école, faciliter l'approvisionnement en produits auprès des agriculteurs locaux et favoriser l'augmentation de la production maraîchère.

  3. Améliorer le traitement de la douleur chez les enfants en Thaïlande ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    21 avr. 2016 ... FLIKR/ROSS POLLOCK. Des lignes directrices sur la gestion de la douleur dans les hôpitaux thaïlandais aident à prévenir ou à traiter la douleur chez les enfants. Global Health Research Initiative. Les enfants sont plus susceptibles que les adultes de souffrir de l'absence de traitement ou de traitement ...

  4. Réponse au stress induit par le transport chez la truite arc-en-ciel (Oncorhynchus mykiss

    Directory of Open Access Journals (Sweden)

    ROUGER Y.

    1998-07-01

    Full Text Available La réponse au stress induit par le transport a été étudiée chez des truites arc-en-ciel immatures d'un poids moyen de 200 g. D'une manière globale, les valeurs de l'hématocrite, de l'osmolarité du plasma sanguin, du Cortisol et de la testostérone sont significativement plus élevées chez les poissons transportés que chez les témoins non transportés, alors que les niveaux de gonadostimuline (GTH1 et d'hormone de croissance ne diffèrent pas suivant les lots. L'analyse du comportement en "open field" des individus de chaque lot montre que les poissons transportés s'immobilisent en moyenne après un temps significativement plus long que les témoins. L'étude des performances zootechniques de chaque lot pendant les deux mois suivant l'expérience indique que le lot transporté récupère rapidement.

  5. Change of selenium in plasma of dairy cows receiving two levels of sodium-selenite during the transition period

    Directory of Open Access Journals (Sweden)

    A. Giubbiotti

    2010-04-01

    Full Text Available With the aim to study the plasma Se content during transition period, 2 groups of 12 dairy cows were monitored the month before and after calving. In stall 1 (S1 cows were tied and individually fed, in stall2 (S2 cows were free and fed TMR. In both stalls cows were supplied with Se as Na-selenite. In S1 3 mg/d of Se were fed mixed with corn silage while, in S2, Se was offered with TMR, in dry period 2 mg/d were added with a mineral-vitamin supplement, in lactation 2.6 mg/d (when DMI was 22.2 kg/d with the concentrate. Forages, the same for both stalls, and concentrates were sampled for chemical composition and Se determination. Cows were checked for milk yield and its content of somatic cells (SCC, health problems, and bled for Se determination in plasma. Average Se intake was higher in S1, in both dry (4.08 vs 2.76 mg/d and lactating (5.80 vs 2.11 mg/d period. Besides the supplementation, differences depended on high Se intake in S1 with the concentrate (increased after calving to 11.5 kg/DM on d 30 and containing 0.24 mg/kg DM of Se. According to the intake, plasma Se content resulted higher in S1 in dry (1.20 vs 0.74 μmol/L and lactating (1.47 vs 0.62 μmol/L cows. In close-up plasma Se decreased in both groups, in first days of lactation increased in S1, while decreased in S2 to level indicating a deficient intake (0.50 μmol/L. These results confirm the link between Se intake and its plasma level. Finally, Se plasma content did not seem related to cow health status during transition period.

  6. Insights into selenite reduction and biogenesis of elemental selenium nanoparticles by two environmental isolates of Burkholderia fungorum.

    Science.gov (United States)

    Khoei, Nazanin Seyed; Lampis, Silvia; Zonaro, Emanuele; Yrjälä, Kim; Bernardi, Paolo; Vallini, Giovanni

    2017-01-25

    Microorganisms capable of transforming toxic selenium oxyanions into non-toxic elemental selenium (Se°) may be considered as biocatalysts for the production of selenium nanoparticles (SeNPs), eventually exploitable in different biotechnological applications. Two Burkholderia fungorum strains (B. fungorum DBT1 and B. fungorum 95) were monitored during their growth for both capacity and efficiency of selenite (SeO 3 2- ) reduction and elemental selenium formation. Both strains are environmental isolates in origin: B. fungorum DBT1 was previously isolated from an oil refinery drainage, while B. fungorum 95 has been enriched from inner tissues of hybrid poplars grown in a soil contaminated by polycyclic aromatic hydrocarbons. Our results showed that B. fungorum DBT1 is able to reduce 0.5mM SeO 3 2- to Se° when cultured aerobically in liquid medium at 27°C, while B. fungorum 95 can reduce more than 1mM SeO 3 2- to Se° within 96h under the same growth conditions, with the appearance of SeNPs in cultures of both bacterial strains. Biogenic SeNPs were spherical, with pH-dependent charge and an average hydrodynamic diameter of 170nm and 200nm depending on whether they were produced by B. fungorum 95 or B. fungorum DBT1, respectively. Electron microscopy analyses evidenced that Se nanoparticles occurred intracellularly and extracellularly. The mechanism of SeNPs formation can be tentatively attributed to cytoplasmic enzymatic activation mediated by electron donors. Biogenic nanoparticles were then probably released outside the bacterial cells as a consequence of a secretory process or cell lysis. Nevertheless, formation of elemental selenium nanoparticles under aerobic conditions by B. fungorum DBT1 and B. fungorum 95 is likely due to intracellular reduction mechanisms. Biomedical and other high tech sectors might exploit these biogenic nanoparticles in the near future, once fully characterized and tested for their multiple properties. Copyright © 2016 Elsevier B.V. All

  7. Facteurs de risque et dépistage du cancer chez les Premières Nations en Ontario

    Directory of Open Access Journals (Sweden)

    Maegan V. Mazereeuw

    2017-01-01

    Full Text Available Introduction : L'absence d'identificateurs, dans les bases de données administratives sur la santé, nous empêche de bien comprendre le fardeau du cancer chez les Premières Nations. Notre étude compare les facteurs de risque et le dépistage du cancer chez les membres des Premières Nations en Ontario (vivant dans des réserves et hors réserves et chez les Ontariens non autochtones, en s'appuyant sur deux enquêtes sur la santé. Méthodologie : Les taux normalisés selon l'âge ont été calculés en utilisant la phase 2 de l'Enquête régionale sur la santé des Premières Nations (ERS de 2008-2010 pour les Premières Nations dans des réserves et l'Enquête sur la santé dans les collectivités canadiennes (ESCC de 2007-2013 pour les membres des Premières Nations hors réserves et les Ontariens non autochtones. Des rapports de taux (RT et des tests du chi carré de Pearson (pour les différences de proportion ont été utilisés pour comparer les estimations entre les membres des Premières Nations (dans des réserves et hors réserves et les Ontariens non autochtones. Résultats : Une proportion plus élevée d'hommes, de femmes et d'adolescents des Premières Nations vivant dans des réserves fumaient (RT = 1,97, 2,78 et 7,21 respectivement et souffraient d'obésité (RT = 1,73, 2,33 et 3,29 respectivement, comparativement à leurs homologues non autochtones. Des tendances similaires ont été observées chez les membres des Premières Nations vivant hors réserves. La consommation excessive ponctuelle d'alcool fréquente était également plus répandue chez les hommes et les femmes des Premières Nations vivant dans des réserves (RT = 1,28 et 2,22, respectivement et hors réserves (RT = 1,70 et 1,45, respectivement que chez les Ontariens non autochtones. Les hommes et les femmes des Premières Nations vivant dans des réserves étaient deux fois moins susceptibles de consommer des fruits au moins deux fois par jour et des l

  8. The SOS Response Master Regulator LexA Regulates the Gene Transfer Agent of Rhodobacter capsulatus and Represses Transcription of the Signal Transduction Protein CckA.

    Science.gov (United States)

    Kuchinski, Kevin S; Brimacombe, Cedric A; Westbye, Alexander B; Ding, Hao; Beatty, J Thomas

    2016-02-01

    The gene transfer agent of Rhodobacter capsulatus (RcGTA) is a genetic exchange element that combines central aspects of bacteriophage-mediated transduction and natural transformation. RcGTA particles resemble a small double-stranded DNA bacteriophage, package random ∼4-kb fragments of the producing cell genome, and are released from a subpopulation (SOS response in many bacteria, as a regulator of RcGTA activity. Deletion of the lexA gene resulted in the abolition of detectable RcGTA production and an ∼10-fold reduction in recipient capability. A search for SOS box sequences in the R. capsulatus genome sequence identified a number of putative binding sites located 5' of typical SOS response coding sequences and also 5' of the RcGTA regulatory gene cckA, which encodes a hybrid histidine kinase homolog. Expression of cckA was increased >5-fold in the lexA mutant, and a lexA cckA double mutant was found to have the same phenotype as a ΔcckA single mutant in terms of RcGTA production. The data indicate that LexA is required for RcGTA production and maximal recipient capability and that the RcGTA-deficient phenotype of the lexA mutant is largely due to the overexpression of cckA. This work describes an unusual phenotype of a lexA mutant of the alphaproteobacterium Rhodobacter capsulatus in respect to the phage transduction-like genetic exchange carried out by the R. capsulatus gene transfer agent (RcGTA). Instead of the expected SOS response characteristic of prophage induction, this lexA mutation not only abolishes the production of RcGTA particles but also impairs the ability of cells to receive RcGTA-borne genes. The data show that, despite an apparent evolutionary relationship to lambdoid phages, the regulation of RcGTA gene expression differs radically. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  9. Alimentation et dépôts lipidiques chez la truite arc-en-ciel, effet de la température d’élevage

    OpenAIRE

    Corraze, Geneviève; Larroquet, Laurence; Médale, Françoise

    1999-01-01

    Cet article fait le point sur la régulation de la genèse des dépôts lipidiques par l’alimentation chez les poissons, sur la base de données bibliographiques existantes et de données personnelles obtenues chez la truite arc-en-ciel (Oncorhynchus mykiss). Chez la truite arc-en-ciel, l’importance quantitative des dépôts lipidiques corporels varie avec la teneur en lipides des aliments, mais les mécanismes de dépôts sont identiques quel que soit le régime alimentaire. Le tissu adipeux périviscéra...

  10. The mutation of carotenoids affects the energy transfer in LH2 light harvesting complexes from Rhodobacter sphaeroides 601 at room temperature

    International Nuclear Information System (INIS)

    Liu Weimin; Liu Yuan; Guo Lijun; Xu Chunhe; Qian Shixiong

    2006-01-01

    Energy transfer in two kinds of peripheral antenna complexes LH2 from Rhodobacter sphaeroides 601 was studied by absorption, fluorescence emission, time-resolved fluorescence and femtosecond transient absorption spectroscopy at room temperature. These two complexes are LH2 (RS601) and green carotenoid mutated LH2 (GM309). The obtained results demonstrate that: (a) compared with spheroidenes, which have ten carbon-carbon double bonds in native RS601, carotenoids in GM309 were identified as containing neurosporenes with nine carbon-carbon double bonds, which show a significant blue shift of ∼20 nm in the three absorption peaks because of the higher energy levels of neurosporene than those of spheroidene, (b) the higher energy levels of neurosporene in GM309 induce a lower B800 → B850 energy transfer rate and efficiency as compared to that in RS601 resulting from the relatively higher band gap between the donor of B800 and the bridge of the carotenoids (c) the same lifetime of the B850 excited singlet state is observed in these two LH2 complexes

  11. Dietary Karaya Saponin and Rhodobacter capsulatus Exert Hypocholesterolemic Effects by Suppression of Hepatic Cholesterol Synthesis and Promotion of Bile Acid Synthesis in Laying Hens

    Directory of Open Access Journals (Sweden)

    Sadia Afrose

    2010-01-01

    Full Text Available This study was conducted to elucidate the mechanism underlying the hypolipidemic action of karaya saponin or Rhodobacter (R. capsulatus. A total of 40 laying hens (20-week-old were assigned into four dietary treatment groups and fed a basal diet (as a control or basal diets supplemented with either karaya saponin, R. capsulatus, or both for 60 days. The level of serum low-density-lipoprotein cholesterol and the levels of cholesterol and triglycerides in the serum, liver, and egg yolk were reduced by all the supplementations (<.05. Liver bile acid concentration and fecal concentrations of cholesterol, triacylglycerol, and bile acid were simultaneously increased by the supplementation of karaya saponin, R. capsulatus, and the combination of karaya saponin and R. capsulatus (<.05. The supplementation of karaya saponin, R. capsulatus, and the combination of karaya saponin and R. capsulatus suppressed the incorporation of 14C from 1-14C-palmitic acid into the fractions of total lipids, phospholipids, triacylglycerol, and cholesterol in the liver in vitro (<.05. These findings suggest that the hypocholesterolemic effects of karaya saponin and R. capsulatus are caused by the suppression of the cholesterol synthesis and the promotion of cholesterol catabolism in the liver.

  12. Resonance Raman and surface-enhanced resonance Raman spectra of LH2 antenna complex from Rhodobacter sphaeroides and Ectothiorhodospira sp. excited in the Qx and Qy transitions.

    Science.gov (United States)

    Chumanov, G; Picorel, R; Ortiz de Zarate, I; Cotton, T M; Seibert, M

    2000-05-01

    Well-resolved vibrational spectra of LH2 complex isolated from two photosynthetic bacteria, Rhodobacter sphaeroides and Ectothiorhodospira sp., were obtained using surface-enhanced resonance Raman scattering (SERRS) exciting into the Qx and the Qy transitions of bacteriochlorophyll a. High-quality SERRS spectra in the Qy region were accessible because the strong fluorescence background was quenched near the roughened Ag surface. A comparison of the spectra obtained with 590 nm and 752 nm excitation in the mid- and low-frequency regions revealed spectral differences between the two LH2 complexes as well as between the LH2 complexes and isolated bacteriochlorophyll a. Because peripheral modes of pigments contribute mainly to the low-frequency spectral region, frequencies and intensities of many vibrational bands in this region are affected by interactions with the protein. The results demonstrate that the microenvironment surrounding the pigments within the two LH2 complexes is somewhat different, despite the fact that the complexes exhibit similar electronic absorption spectra. These differences are most probably due to specific pigment-pigment and pigment-protein interactions within the LH2 complexes, and the approach might be useful for addressing subtle static and dynamic structural variances between pigment-protein complexes from different sources or in complexes altered chemically or genetically.

  13. Nicotinamide nucleotide transhydrogenase from Rhodobacter capsulatus; the H+/H- ratio and the activation state of the enzyme during reduction of acetyl pyridine adenine dinucleotide.

    Science.gov (United States)

    Palmer, T; Jackson, J B

    1992-02-21

    Chromatophores from Rhodobacter capsulatus were incubated in the dark with NADPH and acetylpyridineadenine dinucleotide (AcPdAD+) in the presence of different concentrations of myxothiazol. The transhydrogenase activity was monitored until an appropriate mass action ratio, [AcPdAD+][NADPH]/[AcPdADH][NADP+], was reached. The sample was then illuminated and the initial rate of either AcPdAD+ reduction by NADPH or AcPdADH oxidation by NADP+ was recorded. The ratio of H+ translocated per H- equivalent transferred by transhydrogenase was calculated from the value of the membrane potential (delta pH = 0) at which illumination caused no net reaction in either direction. The mean value for the H+/H- ratio was 0.55. At greater values of [AcPdAD+][NADPH]/[AcPdADH][NADP+] than were employed in the above experiments and over a wider range of concentrations of myxothiazol, it was found that incremental increases in the membrane potential always gave rise to a decrease, never an increase in the rate of AcPdAD+ reduction. In contrast to the H(+)-ATP synthase, there is no evidence of any activation/deactivation of H(+)-transhydrogenase by the protonmotive force.

  14. Enhancement of phototrophic hydrogen production by Rhodobacter sphaeroides ZX-5 using a novel strategy - shaking and extra-light supplementation approach

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xu; Wang, Yong-Hong; Zhang, Si-Liang; Chu, Ju; Zhang, Ming; Huang, Ming-Zhi; Zhuang, Ying-Ping [State Key Laboratory of Bioreactor Engineering, P.O. Box 329, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China)

    2009-12-15

    Biohydrogen has gained attention due to its potential as a sustainable alternative to conventional methods for hydrogen production. In this study, the effect of light intensity as well as cultivation method (standing- and shaking-culture) on the cell growth and hydrogen production of Rhodobacter sphaeroides ZX-5 were investigated in 38-ml anaerobic photobioreactor with RCVBN medium. Thus, a novel shaking and extra-light supplementation (SELS) approach was developed to enhance the phototrophic H{sub 2} production by R. sphaeroides ZX-5 using malate as the sole carbon source. The optimum illumination condition for shaking-culture by strain ZX-5 increased to 7000-8000 lux, markedly higher than that for standing-culture (4000-5000 lux). Under shaking and elevated illumination (7000-8000 lux), the culture was effective in promoting photo-H{sub 2} production, resulting in a 59% and 56% increase of the maximum and average hydrogen production rate, respectively, in comparison with the culture under standing and 4000-5000 lux conditions. The highest hydrogen-producing rate of 165.9 ml H{sub 2}/l h was observed under the application of SELS approach. To our knowledge, this record is currently the highest hydrogen production rate of non-immobilized purple non-sulphur (PNS) bacteria. This optimal performance of photo-H{sub 2} production using SELS approach is a favorable choice of sustainable and economically feasible strategy to improve phototrophic H{sub 2} production efficiency. (author)

  15. Exploitation of dark fermented effluent of cheese whey by co-culture of Rhodobacter sphaeroides and Bacillus firmus for photo-hydrogen production.

    Science.gov (United States)

    Pandey, A; Pandey, A

    2017-07-31

    In this study photo-hydrogen production from cheese whey dark fermentation (DF) effluent by the co-culture of Rhodobacter sphaeroides -NMBL-01 and Bacillus firmus - NMBL-03 has been reported. The effect of pH, initial chemical oxygen demand (COD) and the concentration effect of FeSO4.7H2O on photo-hydrogen production have been investigated. The end products of dark fermentation effluent of cheese whey were mainly comprised of soluble organic acids, i.e. butyric acid and lactic acid. The batch process was carried out under light intensity of 2.5 kLux at 32 ± 2oC without any addition of extra carbon and nitrogen source. The single parameter optimization studies revealed optimum pH 6.5, initial COD 4.71 g/L and supplementation of Fe2+ concentration 100 mg/L. The maximum cumulative hydrogen production and yield were found to be 469 ± 45.8 ml H2/L and 146.56 ± 14.31 ml H2/g COD reduced (67.9% reduction in COD) respectively. The mutual interactions among the process parameters were also investigated by three factorial Box-Behnken design of response surface methodology. The optimized experimental values were found concurrent with the calculated values obtained from the theoretical model.

  16. Effect of light-dark cycles on hydrogen and poly-β-hydroxybutyrate production by a photoheterotrophic culture and Rhodobacter capsulatus using a dark fermentation effluent as substrate.

    Science.gov (United States)

    Montiel Corona, Virginia; Le Borgne, Sylvie; Revah, Sergio; Morales, Marcia

    2017-02-01

    A Rhodobacter capsulatus strain and a photoheterotrophic culture (IZT) were cultivated to produce hydrogen under different light-dark cycles. A dark fermentation effluent (DFE) was used as substrate. It was found that IZT culture had an average cumulative hydrogen production (Paccum H 2 ) of 1300±43mLH 2 L -1 under continuous illumination and light-dark cycles of 30 or 60min. In contrast, R. capsulatus reduced its Paccum H 2 by 20% under 30:30min light-dark cycles, but tripled its poly-β-hydroxybutyrate (PHB) content (308±2mgPHB gdw -1 ) compared to continuous illumination. The highest PHB content by IZT culture was 178±10mgPHB gdw -1 under 15:15min light-dark cycles. PCR-DGGE analysis revealed that the IZT culture was mainly composed of Rhodopseudomonas palustris identified with high nucleotide similarity (99%). The evaluated cultures might be used for hydrogen and PHB production. They might provide energy savings by using light-dark cycles and DFE valorization. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Effects of the cryptochrome CryB from Rhodobacter sphaeroides on global gene expression in the dark or blue light or in the presence of singlet oxygen.

    Directory of Open Access Journals (Sweden)

    Sebastian Frühwirth

    Full Text Available Several regulators are controlling the formation of the photosynthetic apparatus in the facultatively photosynthetic bacterium Rhodobacter sphaeroides. Among the proteins affecting photosynthesis gene expression is the blue light photoreceptor cryptochrome CryB. This study addresses the effect of CryB on global gene expression. The data reveal that CryB does not only influence photosynthesis gene expression but also genes for the non-photosynthetic energy metabolism like citric acid cycle and oxidative phosphorylation. In addition several genes involved in RNA processing and in transcriptional regulation are affected by a cryB deletion. Although CryB was shown to undergo a photocycle it does not only affect gene expression in response to blue light illumination but also in response to singlet oxygen stress conditions. While there is a large overlap in these responses, some CryB-dependent effects are specific for blue-light or photooxidative stress. In addition to protein-coding genes some genes for sRNAs show CryB-dependent expression. These findings give new insight into the function of bacterial cryptochromes and demonstrate for the first time a function in the oxidative stress response.

  18. Potential of Rhodobacter capsulatus Grown in Anaerobic-Light or Aerobic-Dark Conditions as Bioremediation Agent for Biological Wastewater Treatments

    Directory of Open Access Journals (Sweden)

    Stefania Costa

    2017-02-01

    Full Text Available The use of microorganisms to clean up wastewater provides a cheaper alternative to the conventional treatment plant. The efficiency of this method can be improved by the choice of microorganism with the potential of removing contaminants. One such group is photosynthetic bacteria. Rhodobacter capsulatus is a purple non-sulfur bacterium (PNSB found to be capable of different metabolic activities depending on the environmental conditions. Cell growth in different media and conditions was tested, obtaining a concentration of about 108 CFU/mL under aerobic-dark and 109 CFU/mL under anaerobic-light conditions. The biomass was then used as a bioremediation agent for denitrification and nitrification of municipal wastewater to evaluate the potential to be employed as an additive in biological wastewater treatment. Inoculating a sample of mixed liquor withdrawn from the municipal wastewater treatment plant with R. capsulatus grown in aerobic-dark and anaerobic-light conditions caused a significant decrease of N-NO3 (>95%, N-NH3 (70% and SCOD (soluble chemical oxygen demand (>69%, independent of the growth conditions. A preliminary evaluation of costs indicated that R. capsulatus grown in aerobic-dark conditions could be more convenient for industrial application.

  19. Chronic Exposure to Rhodobacter Sphaeroides Extract Lycogen™ Prevents UVA-Induced Malondialdehyde Accumulation and Procollagen I Down-Regulation in Human Dermal Fibroblasts

    Science.gov (United States)

    Yang, Tsai-Hsiu; Lai, Ying-Hsiu; Lin, Tsuey-Pin; Liu, Wen-Sheng; Kuan, Li-Chun; Liu, Chia-Chyuan

    2014-01-01

    UVA contributes to the pathogenesis of skin aging by downregulation of procollagen I content and induction of matrix metalloproteinase (MMP)-associated responses. Application of antioxidants such as lycopene has been demonstrated as a convenient way to achieve protection against skin aging. Lycogen™, derived from the extracts of Rhodobacter sphaeroides, exerts several biological effects similar to that of lycopene whereas most of its anti-aging efficacy remains uncertain. In this study, we attempted to examine whether Lycogen™ could suppress malondialdehyde (MDA) accumulation and restore downregulated procollagen I expression induced by UVA exposure. In human dermal fibroblasts Hs68 cells, UVA repressed cell viability and decreased procollagen I protein content accompanied with the induction of MMP-1 and MDA accumulation. Remarkably, incubation with 50 μM Lycogen™ for 24 h ameliorated UVA-induced cell death and restored UVA-induced downregulation of procollagen in a dose-related manner. Lycogen™ treatment also prevented the UVA-induced MMP-1 upregulation and intracellular MDA generation in Hs68 cells. Activation of NFκB levels, one of the downstream events induced by UVA irradiation and MMP-1 induction, were also prevented by Lycogen™ administration. Taken together, our findings demonstrate that Lycogen™ may be an alternative agent that prevents UVA-induced skin aging and could be used in cosmetic and pharmaceutical applications. PMID:24463291

  20. Removal of the effect of ammonium on the regulation of nitrogenase enzyme in Rhodobacter capsulatus DSM1710 for improved hydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Pekgoez, Guelsah; Guenduez, Ufuk [Middle East Technical Univ. (Turkey). Dept. of Biology; Eroglu, Inci [Middle East Technical Univ. (Turkey). Dept. of Chemical Engineering; Rakhely, Gabor [Szeged Univ. (Hungary). Dept. of Biotechnology

    2010-07-01

    Photofermentative biohydrogen production by purple non-sulfur (PNS) bacteria is a renewable and clean way of producing hydrogen. Hydrogen production by PNS bacteria, Rhodobacter capsulatus, is mediated mainly by nitrogenases, which primarily fix molecular nitrogen to ammonium and produce hydrogen as byproduct. The reaction catalyzed by nitrogenases requires a lot of energy. Hence, there is a complex regulation on nitrogenase enzyme complex, consequently, on hydrogen production. Whenever ammonium, which is the end product of nitrogen fixation reaction, is found in the environment, hydrogen production stops. GlnB and GlnK proteins are the critical regulatory proteins in ammonium dependent regulation of the nitrogenase gene expression. In this study, the aim is to release the ammonium regulation on nitrogenase enzyme by inactivating glnB and glnK genes. For this purpose, relevant recombinant vectors were constructed; R.capsulatus glnB- strain was obtained. The double R.capsulatus glnB{sup -}glnK{sup -} strain, able to produce hydrogen independent of ammonium concentration of the environment is to be obtained. (orig.)

  1. Quenching Capabilities of Long-Chain Carotenoids in Light-Harvesting-2 Complexes from Rhodobacter sphaeroides with an Engineered Carotenoid Synthesis Pathway.

    Science.gov (United States)

    Dilbeck, Preston L; Tang, Qun; Mothersole, David J; Martin, Elizabeth C; Hunter, C Neil; Bocian, David F; Holten, Dewey; Niedzwiedzki, Dariusz M

    2016-06-23

    Six light-harvesting-2 complexes (LH2) from genetically modified strains of the purple photosynthetic bacterium Rhodobacter (Rb.) sphaeroides were studied using static and ultrafast optical methods and resonance Raman spectroscopy. These strains were engineered to incorporate carotenoids for which the number of conjugated groups (N = NC═C + NC═O) varies from 9 to 15. The Rb. sphaeroides strains incorporate their native carotenoids spheroidene (N = 10) and spheroidenone (N = 11), as well as longer-chain analogues including spirilloxanthin (N = 13) and diketospirilloxantion (N = 15) normally found in Rhodospirillum rubrum. Measurements of the properties of the carotenoid first singlet excited state (S1) in antennas from the Rb. sphaeroides set show that carotenoid-bacteriochlorophyll a (BChl a) interactions are similar to those in LH2 complexes from various other bacterial species and thus are not significantly impacted by differences in polypeptide composition. Instead, variations in carotenoid-to-BChl a energy transfer are primarily regulated by the N-determined energy of the carotenoid S1 excited state, which for long-chain (N ≥ 13) carotenoids is not involved in energy transfer. Furthermore, the role of the long-chain carotenoids switches from a light-harvesting supporter (via energy transfer to BChl a) to a quencher of the BChl a S1 excited state B850*. This quenching is manifested as a substantial (∼2-fold) reduction of the B850* lifetime and the B850* fluorescence quantum yield for LH2 housing the longest carotenoids.

  2. Histotopography of the radiopharmaceuticals 75Se-selenomethionine and 75Se-selenite in critical organs of adult and embryonic mice

    International Nuclear Information System (INIS)

    Khant, S.E.; Norets, T.A.

    1981-01-01

    Adult male and pregnant mice received 75 Se-labelled methionine and selenite, resp. The critical organs and the embryos were examined histoautoradiographically at different time intervals as to the organ distribution of the radiopharmaceuticals. All organs revealed a heterogeneity of the 75 Se distribution with an intensity being unequally organo-specific and depending on the type of the radiopharmaceutical. 75 Se-selenomethionine was deposited mainly in functional areas of kidneys, liver, bone marrow and testes thus causing a long-term retention and an intensive irradiation of these organs. In the embryos 75 Se-seleno-methionine was distributed unequally preferring liver, hematopoietic areas of the bone marrow and the lens

  3. Removal of selenite by zero-valent iron combined with ultrasound: Se(IV) concentration changes, Se(VI) generation, and reaction mechanism.

    Science.gov (United States)

    Fu, Fenglian; Lu, Jianwei; Cheng, Zihang; Tang, Bing

    2016-03-01

    In this paper, the performance and application of zero-valent iron (ZVI) assisted by ultrasonic irradiation for the removal of selenite (Se(IV)) in wastewater was evaluated and reaction mechanism of Se(IV) with ZVI in such systems was investigated. A series of batch experiments were conducted to determine the effects of ultrasound power, pH, ZVI concentration, N2 and air on Se(IV) removal. ZVI before and after reaction with Se(IV) was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Results indicated that ultrasound can lead to a significant synergy in the removal of Se(IV) by ZVI because ultrasound can promote the generation of OH and accelerate the advanced Fenton process. The primary reaction products of ZVI and Se(IV) were Se(0), ferrihydrite, and Fe2O3. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Effects of foliar dressing of selenite and silicate alone or combined with different soil ameliorants on the accumulation of As and Cd and antioxidant system in Brassica campestris.

    Science.gov (United States)

    Ding, Yongzhen; Wang, Yongjiu; Zheng, Xiangqun; Cheng, Weimin; Shi, Rongguang; Feng, Renwei

    2017-08-01

    This study was conducted to investigate the possibility of using a combined technology to synchronously reduce As and Cd accumulation in the edible parts of Brassica campestris. The results showed that a foliar application of selenite (Se) and silicon (Si) combined with soil ameliorants (including Ca-Mg-P fertilizer, sodium silicate and red mud) showed limited effects on the growth of B. campestris. The As concentration in the leaves of B. campestris in all treatments was below the Chinese safety standard. When sodium silicate and Ca-Mg-P fertilizer were added to the soil, the additional foliar application of Se and Si could in some cases help further reduce the concentrations of As and Cd in the leaves of B. campestris. However, when red mud was applied to the soil, the foliar application of Se and Si enhanced the Cd concentration in the leaves of B. campestris. In most cases, high levels of soil ameliorants plus foliar application of Se and Si significantly enhanced the As concentrations in both the soil solution and the roots of B. campestris but reduced the soil solution Cd concentration and the leaf As concentration. Most of the treatments reduced the thiobarbituric acid reactive substances (TBARS) concentration in the leaves of B. campestris, and the foliar application of Se and Si helped the soil ameliorants alleviate the oxidative stress resulting from As and Cd exposure. In this study, several treatments significantly increased the activities of superoxide dismutase (SOD) and ascorbate peroxidase (APX). However, the enzymes peroxidase (POD) and catalase (CAT) were not induced by most treatments. In summary, the combined treatment of 1gkg -1 Ca-Mg-P fertilizer plus foliar spraying 2mmolL -1 sodium selenite was most effective in reducing the Cd concentration and a rather strong ability to reduce the As concentration and trigger the activities of SOD and APX in the leaves of B. campestris. Copyright © 2017 Elsevier Inc. All rights reserved.

  5. Pseudomonas moraviensis subsp. stanleyae, a bacterial endophyte of hyperaccumulator Stanleya pinnata, is capable of efficient selenite reduction to elemental selenium under aerobic conditions.

    Science.gov (United States)

    Staicu, L C; Ackerson, C J; Cornelis, P; Ye, L; Berendsen, R L; Hunter, W J; Noblitt, S D; Henry, C S; Cappa, J J; Montenieri, R L; Wong, A O; Musilova, L; Sura-de Jong, M; van Hullebusch, E D; Lens, P N L; Reynolds, R J B; Pilon-Smits, E A H

    2015-08-01

    To identify bacteria with high selenium tolerance and reduction capacity for bioremediation of wastewater and nanoselenium particle production. A bacterial endophyte was isolated from the selenium hyperaccumulator Stanleya pinnata (Brassicaceae) growing on seleniferous soils in Colorado, USA. Based on fatty acid methyl ester analysis and multi-locus sequence analysis (MLSA) using 16S rRNA, gyrB, rpoB and rpoD genes, the isolate was identified as a subspecies of Pseudomonas moraviensis (97.3% nucleotide identity) and named P. moraviensis stanleyae. The isolate exhibited extreme tolerance to SeO3(2-) (up to 120 mmol l(-1)) and SeO4(2-) (>150 mmol l(-1)). Selenium oxyanion removal from growth medium was measured by microchip capillary electrophoresis (detection limit 95 nmol l(-1) for SeO3(2-) and 13 nmol l(-1) for SeO4(2-)). Within 48 h, P. moraviensis stanleyae aerobically reduced SeO3(2-) to red Se(0) from 10 mmol l(-1) to below the detection limit (removal rate 0.27 mmol h(-1) at 30 °C); anaerobic SeO3(2-) removal was slower. No SeO4(2-) removal was observed. Pseudomonas moraviensis stanleyae stimulated the growth of crop species Brassica juncea by 70% with no significant effect on Se accumulation. Pseudomonas moraviensis stanleyae can tolerate extreme levels of selenate and selenite and can deplete high levels of selenite under aerobic and anaerobic conditions. Pseudomonas moraviensis subsp. stanleyae may be useful for stimulating plant growth and for the treatment of Se-laden wastewater. © 2015 The Society for Applied Microbiology.

  6. THE EFFECTS OF SODIUM SELENITE AND SELENIZED YEAST SUPPLEMENTATION INTO DIET FOR LAYING HENS ON SELECTED QUALITATIVE PARAMETERS OF TABLE EGGS

    Directory of Open Access Journals (Sweden)

    HENRIETA ARPÁŠOVÁ

    2009-10-01

    Full Text Available In this experiment the effects of supplementation of the diet for laying hens with sodium selenite (SS or selenized yeast (SY on whole egg and egg shell quality of layers were studied. The chickens of Shaver Starcross 288 strain were randomly divided at the day of hatching into 4 groups (n=12; in each. The birds were fed from Day 1 of life to 9 months of age with diets differing in amounts and/or forms of selenium. Control group received basal diet (BD containing selenium naturally occurring in feeds (0.1 mg Se/kg of dry matter (DM. First and second experimental group of chickens were fed with a same BD enriched with equivalent dose of Se 0.4 mg/kg DM in form of sodium selenite or selenized yeast, respectively. The feed for third experimental group of birds consisted of BD supplemented with selenized yeast to the final amount of selenium 1.0 mg/kg DM. The egg weight was significantly higher in the groups with SY supplementation only. On the contrary the egg shell ratio was significantly lower in the groups with SY supplementation in both amounts. The width of egg was significantly increased in the groups with selenium supplementation in both forms. The value of egg shell strength was significantly decreased in group with SY in the highest amount 0.9 mg/kg DM The average egg shell thickness was the highest in the experimental group with Se-yeast in amount 0.9 mg/kg DM, however different was not significant compared with control group. The results showed that the most of selected parameters of egg quality appeared to be significantly influenced by selenium supplementation into laying hen’s basal diet.

  7. Échecs thérapeutiques chez les enfants infectés par le VIH en suivi ...

    African Journals Online (AJOL)

    Introduction: L'objectif de cette étude était de déterminer les facteurs associés aux échecs thérapeutiques chez les enfants infectés par le VIH à l'Hôpital Laquintinie de Douala. Méthodes: Une étude transversale rétrospective a été menée sur une période de 5 mois en 2010, recrutant 222 enfants âgés de 1 à 18 ans et sous ...

  8. S'attaquer au chômage chez les jeunes en Éthiopie grâce au ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Le chômage chez les jeunes constitue un problème de taille aussi bien pour les pays industrialisés que pour les pays en développement. L'Éthiopie ne fait pas exception. Quels sont les politiques et les programmes qui favorisent l'emploi des jeunes et quel rôle le secteur privé peut-il jouer à cet égard ? Le présent projet ...

  9. La grossesse chez l'adolescente à l'hôpital de Tsévié (Togo ...

    African Journals Online (AJOL)

    Objectif : Décrire le profil des grossesses chez l'adolescente à l'hôpital de Tsévié (Togo). Matériel et méthode : Il s'agissait d'une étude descriptive analytique portant sur les dossiers des parturientes âgées de 10 à 19 ans reçues à l'hôpital de Tsévié entre janvier 2011 et juin 2012. Résultats : Au cours de cette période, 180 ...

  10. Les effets potentiels du taping chez une population adulte souffrant d'un conflit sous-acromial

    OpenAIRE

    Roch, Sylvie; Thétaz, Alain; Balthazard, Pierre

    2012-01-01

    Introduction : Le conflit sous-acromial est une pathologie fréquente qui touche une grande partie de la population. Quelques revues de la littérature recommandent une prise en charge spécifique, mais peu d’études proposent le taping comme adjuvant aux traitements préconisés. Ainsi ce travail de bachelor a pour objectif de déterminer les effets potentiels du taping chez une population adulte souffrant de conflit sous-acromial. Méthodologie : Notre recherche d’études s’est effectuée de janvier ...

  11. Epidémiologie de l'infection urinaire chez l'enfant au CHU-Campus ...

    African Journals Online (AJOL)

    Titre : Epidémiologie de l'infection urinaire chez l'enfant au CHU-Campus de Lomé. Objectif : Evaluer la prévalence et étudier l'épidémiologie des infections urinaires. Méthodologie : Il s'agit d'une étude prospective qui s'est déroulée du 1er janvier au 31décembre 2009, dans le service de pédiatrie du CHU-Campus de ...

  12. La poétique de la contradiction chez Nelly Arcan

    Directory of Open Access Journals (Sweden)

    Laurence Gauvreau

    2015-12-01

    Full Text Available L’autofiction chez Nelly Arcan, en plus de mettre en scène l’union atypique, bien que déjà vue, de l’écriture et de la prostitution, donne l’impression d’être tout entier un rassemblement de pensées opposées, incompatibles, en désordre. S’opposer à soi-même peut montrer l’existence d’un esprit critique, en plus de la capacité à pousser celui-ci au-delà du simple débat entre amis. La critique négative et la négativité de la critique pénètrent profondément le processus d’écriture dans les autofictions d’Arcan, Putain et Folle, et cette dernière possède définitivement un esprit critique. Par contre, celui-ci ne semble pas la source des oppositions qui caractérisent sa plume. La poétique de l’auteure semble en effet être fondée sur l’utilisation constante d’une série de contradictions. C’est dans la tension de l’exploration de ces contradictions, de la force de cette dialectique négative, qu’Arcan tente de faire éclater le sens des préjugés, de ce qui a été jugé d’avance sans aucun esprit critique, afin d’atteindre une conception et une compréhension qui seraient plus authentiques.

  13. La prise en charge des morsures de chien chez les enfants

    Science.gov (United States)

    Sabhaney, Vikram; Goldman, Ran D.

    2012-01-01

    Résumé Question Une fillette de 4 ans jouait avec le chien de ses voisins. Le chien s’est excité et a mordu la jeune fille à l’avant-bras, y laissant une plaie punctiforme. À cause cette blessure, elle s’est présentée à mon bureau. Devrais-je la traiter avec des antibiotiques? Quel antibiotique faut-il utiliser et pendant combien de temps? Réponse L’administration d’antibiotiques prophylactiques est indiquée lorsqu’on a procédé à une suture primitive de la morsure, que la plaie est de gravité modérée à sévère, qu’elle est punctiforme (particulièrement s’il y a eu pénétration de l’os, de la gaine tendineuse ou de l’articulation), pour les morsures au visage, aux mains, aux pieds ou aux parties génitales ou lorsque les victimes sont immunodéprimées ou souffrent d’asplénisme. L’antibiotique de première intention est l’amoxicilline-clavulanate. La prophylaxie appropriée antitétanique et contre la rage devrait faire partie des soins chez un patient qui a été mordu par un chien, tout comme le débridement local et le nettoyage complet de la plaie.

  14. Les interactions entre la reproduction et la biologie des populations chez les Monogènes Gyrodactylidae : revue

    Directory of Open Access Journals (Sweden)

    HARRIS P. D.

    1993-01-01

    Full Text Available Les Gyrodactylidae sont des Monogènes vivipares, les embryons se développent de manière emboitée dans l'utérus maternel. Les premier et deuxième individus fils se développent sans auto, ni fécondation croisée ; seuls les troisième et suivants peuvent se développer sexuellement. L'importance relative de la reproduction sexuée, dépend de la structure d'âge de la population et de la mortalité. Chez Macrogyrodactylus polypteri, le développement postnatal de l'appareil génital femelle facilite la fécondation croisée chez tous les individus suivant la seconde naissance. La reproduction asexuée maximise la croissance de la population mais la sexualité intervient régulièrement. Gyrdicotylus gallieni, qui parasite la bouche de Xenopus laevis, présente une croissance exceptionnellement lente de la population et les populations parasites sont surtout composées d'individus âgés et sexuellement matures. Isancistrum subulatae, parasite du Calmar Alloteuthis subulata, forme d'importantes populations, mais leur croissance est probablement lente, et la structure d'âge suggère que la sexualité est courante. Chez Gyrodactylus, plusieurs stratégies existent. Gyrodactylus turnbulli, chez les Guppis, a une courte durée de vie et manifeste une mortalité spécifique croissant exponentiellement avec l'âge, de telle sorte que moins d'un pour cent survivent assez longtemps pour donner une troisième naissance. La reproduction est principalement asexuée mais le sexe intervient dans les populations de très fortes densités. Dans la nature la reproduction asexuée prédomine sans doute et cette espèce peut être considérée comme cycliquement parthénogénétique. Chez le saumon, Gyrodactylus salaris, présente des mortalités faibles et 10-15% des survivants se reproduisent sexuellement. Des individus fécondés sont trouvés même dans les faibles infestations et la sexualité est habituelle dans la biologie de cette espèce. Chez

  15. Après le spectacle : les impacts psychosociaux de consommation de pornographie homosexuelle masculine chez les hommes gais

    Directory of Open Access Journals (Sweden)

    SIMON CORNEAU

    2010-01-01

    Full Text Available Cette recherche qualitative exploratoire vise à mettre à jour les impacts psychosociaux possibles de consommation de pornographie homosexuelle masculine à travers les discours de 20 usagers gais de Toronto (Canada. La consommation de pornographie semble plus acceptée et normalisée chez les hommes gais que chez les hommes hétérosexuels. Une telle consommation peut avoir une incidence sur certains aspects de la santé sexuelle et de la santé mentale. L'analyse thématique du corpus de nos données nous révèle que les impacts peuvent se faire sentir au niveau de l'apprentissage, de l'édification de la fantasmatique, de la validation de la sexualité entre hommes, de l'ingérence dans la vie sexuelle et enfin, sur l'habituation et sur l'image de soi/image corporelle. À l'aide de l’analyse critique de discours, nous avons pu documenter les discours sociaux plus larges en jeu dans les récits des usagers et voir de quelle façon ils se positionnent à l'intérieur de ces mêmes discours.

  16. MODULATION DE L’INSULINO-SECRETION PAR LES CYTOKINES CHEZ LE RAT DES SABLES ET LE RAT WISTAR: ETUDE INTERSPECIFIQUE

    Directory of Open Access Journals (Sweden)

    A HADDAR

    2001-12-01

    Dans cette étude, nous avons comparé l’activité insulinosécrétoire des îlots de Langerhans isolés du rat Wistar et du rat des sables, afin de déterminer les variation interspécifiques. Nos résultats préliminaires indiquent que l'effet le plus probant est observé en présence de l’IL-1b. En effet, cette cytokine stimule la sécrétion d’insuline de manière dose-dépendante également chez le rat des sables; toutefois, l'amplitude de la réponse est plus prononcée chez le rongeur désertique, avec une augmentation du taux de l’insuline libérée de l’ordre de 147%, en présence d’une concentration de 20 UI/ml de l’IL-1b, comparée à la sécrétion basale. Quant à l’IL-2, nous n’avons enregistré aucune modification dans l’activité insulinosécrétoire des 2 espèces.

  17. Brûlure chez l’épileptique: brûlure pas comme les autres

    Science.gov (United States)

    Boukind, S.; Elatiqi, O.K.; Dlimi, M.; Elamrani, D.; Benchamkha, Y.; Ettalbi, S.

    2015-01-01

    Summary L’association brûlure et épilepsie est une constatation fréquente au Maroc. Ces brûlures, souvent itératives, touchent le plus souvent des femmes jeunes de milieu rural. L’accident survient habituellement au domicile, le plus souvent dans la cuisine à la suite d’une chute sur un moyen de cuisson posé au sol. Elles peuvent être inaugurales de la maladie mais surviennent plus souvent chez des patients connus mais au traitement mal suivi. Les conséquences de ces brûlures, toujours profondes, sont souvent dramatiques en termes de séquelles, chez des patients ayant déjà une insertion sociale rendue difficile par l’épilepsie. La prise en charge doit être multidisciplinaire et concerner à la fois la brûlures et l’épilepsie. Des mesures de prévention simples, visant à équilibrer l’épilepsie et éviter au patient de se trouver seul à proximité d’une source de chaleur, doivent être mises en place. PMID:27252613

  18. Electron spin relaxation enhancement measurements of interspin distances in human, porcine, and Rhodobacter electron transfer flavoprotein-ubiquinone oxidoreductase (ETF-QO).

    Science.gov (United States)

    Fielding, Alistair J; Usselman, Robert J; Watmough, Nicholas; Simkovic, Martin; Frerman, Frank E; Eaton, Gareth R; Eaton, Sandra S

    2008-02-01

    Electron transfer flavoprotein-ubiquinone oxidoreductase (ETF-QO) is a membrane-bound electron transfer protein that links primary flavoprotein dehydrogenases with the main respiratory chain. Human, porcine, and Rhodobacter sphaeroides ETF-QO each contain a single [4Fe-4S](2+,1+) cluster and one equivalent of FAD, which are diamagnetic in the isolated enzyme and become paramagnetic on reduction with the enzymatic electron donor or with dithionite. The anionic flavin semiquinone can be reduced further to diamagnetic hydroquinone. The redox potentials for the three redox couples are so similar that it is not possible to poise the proteins in a state where both the [4Fe-4S](+) cluster and the flavoquinone are fully in the paramagnetic form. Inversion recovery was used to measure the electron spin-lattice relaxation rates for the [4Fe-4S](+) between 8 and 18K and for semiquinone between 25 and 65K. At higher temperatures the spin-lattice relaxation rates for the [4Fe-4S](+) were calculated from the temperature-dependent contributions to the continuous wave linewidths. Although mixtures of the redox states are present, it was possible to analyze the enhancement of the electron spin relaxation of the FAD semiquinone signal due to dipolar interaction with the more rapidly relaxing [4Fe-4S](+) and obtain point-dipole interspin distances of 18.6+/-1A for the three proteins. The point-dipole distances are within experimental uncertainty of the value calculated based on the crystal structure of porcine ETF-QO when spin delocalization is taken into account. The results demonstrate that electron spin relaxation enhancement can be used to measure distances in redox poised proteins even when several redox states are present.

  19. Functional characteristics of spirilloxanthin and keto-bearing Analogues in light-harvesting LH2 complexes from Rhodobacter sphaeroides with a genetically modified carotenoid synthesis pathway.

    Science.gov (United States)

    Niedzwiedzki, Dariusz M; Dilbeck, Preston L; Tang, Qun; Mothersole, David J; Martin, Elizabeth C; Bocian, David F; Holten, Dewey; Hunter, C Neil

    2015-01-01

    Light-harvesting 2 (LH2) complexes from a genetically modified strain of the purple photosynthetic bacterium Rhodobacter (Rba.) sphaeroides were studied using static and ultrafast optical methods and resonance Raman spectroscopy. Carotenoid synthesis in the Rba. sphaeroides strain was engineered to redirect carotenoid production away from spheroidene into the spirilloxanthin synthesis pathway. The strain assembles LH2 antennas with substantial amounts of spirilloxanthin (total double-bond conjugation length N=13) if grown anaerobically and of keto-bearing long-chain analogs [2-ketoanhydrorhodovibrin (N=13), 2-ketospirilloxanthin (N=14) and 2,2'-diketospirilloxanthin (N=15)] if grown semi-aerobically (with ratios that depend on growth conditions). We present the photophysical, electronic, and vibrational properties of these carotenoids, both isolated in organic media and assembled within LH2 complexes. Measurements of excited-state energy transfer to the array of excitonically coupled bacteriochlorophyll a molecules (B850) show that the mean lifetime of the first singlet excited state (S1) of the long-chain (N≥13) carotenoids does not change appreciably between organic media and the protein environment. In each case, the S1 state appears to lie lower in energy than that of B850. The energy-transfer yield is ~0.4 in LH2 (from the strain grown aerobically or semi-aerobically), which is less than half that achieved for LH2 that contains short-chain (N≤11) analogues. Collectively, the results suggest that the S1 excited state of the long-chain (N≥13) carotenoids participates little if at all in carotenoid-to-BChl a energy transfer, which occurs predominantly via the carotenoid S2 excited state in these antennas. Copyright © 2015 Elsevier B.V. All rights reserved.

  20. Monomeric RC-LH1 core complexes retard LH2 assembly and intracytoplasmic membrane formation in PufX-minus mutants of Rhodobacter sphaeroides.

    Science.gov (United States)

    Adams, Peter G; Mothersole, David J; Ng, Irene W; Olsen, John D; Hunter, C Neil

    2011-09-01

    In the model photosynthetic bacterium Rhodobacter sphaeroides domains of light-harvesting 2 (LH2) complexes surround and interconnect dimeric reaction centre-light-harvesting 1-PufX (RC-LH1-PufX) 'core' complexes, forming extensive networks for energy transfer and trapping. These complexes are housed in spherical intracytoplasmic membranes (ICMs), which are assembled in a stepwise process where biosynthesis of core complexes tends to dominate the early stages of membrane invagination. The kinetics of LH2 assembly were measured in PufX mutants that assemble monomeric core complexes, as a consequence of either a twelve-residue N-terminal truncation of PufX (PufXΔ12) or the complete removal of PufX (PufX(-)). Lower rates of LH2 assembly and retarded maturation of membrane invagination were observed for the larger and less curved ICM from the PufX(-) mutant, consistent with the proposition that local membrane curvature, initiated by arrays of bent RC-LH1-PufX dimers, creates a favourable environment for stable assembly of LH2 complexes. Transmission electron microscopy and high-resolution atomic force microscopy were used to examine ICM morphology and membrane protein organisation in these mutants. Some partitioning of core and LH2 complexes was observed in PufX(-) membranes, resulting in locally ordered clusters of monomeric RC-LH1 complexes. The distribution of core and LH2 complexes in the three types of membrane examined is consistent with previous models of membrane curvature and domain formation (Frese et al., 2008), which demonstrated that a combination of crowding and asymmetries in sizes and shapes of membrane protein complexes drives membrane organisation. 2011 Elsevier B.V. All rights reserved.

  1. Manipulating the Energetics and Rates of Electron Transfer in Rhodobacter capsulatus Reaction Centers with Asymmetric Pigment Content

    Energy Technology Data Exchange (ETDEWEB)

    Faries, Kaitlyn M. [Department; Dylla, Nicholas P. [Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Hanson, Deborah K. [Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Holten, Dewey [Department; Laible, Philip D. [Biosciences Division, Argonne National Laboratory, Lemont, Illinois 60439, United States; Kirmaier, Christine [Department

    2017-07-17

    Seemingly redundant parallel pathways for electron transfer (ET), composed of identical sets of cofactors, are a cornerstone feature of photosynthetic reaction centers (RCs) involved in light-energy conversion. In native bacterial RCs, both A and B branches house one bacteriochlorophyll (BChl) and one bacteriopheophytin (BPh), but the A branch is used exclusively. Described herein are the results-obtained for two Rhodobacter capsulatus RCs with an unnaturally high degree of cofactor asymmetry, two BPh on the RC's B side and two BChl on the A side. These pigment changes derive, respectively, from the His(M180)Leu mutation [a BPh ((Phi(B)) replaces the B-side BChl (BB)], and the Leu(M212)His mutation [a BChl (beta(A))) replaces the A-side BPh (H-A)]. Additionally, Tyr(M208)Phe was employed to disfavor ET to the A branch; in one mutant, Val(M131)Glu creates a hydrogen bond to H-B to enhance ET to H-B. In both Phi(B) mutants, the decay kinetics of the excited primary ET donor (P*) resolve three populations with lifetimes of similar to 9 ps (50-60%), similar to 40 ps (10-20%), and similar to 200 ps (20-30%), with P+Phi(-)(B) formed predominantly from the 9 ps fraction. The 50-60% yield of P+Phi(B)- is the highest yet observed for a Phi(B)-containing RC. The results provide insight into factors needed for efficient multistep ET.

  2. Role of Rhodobacter sphaeroides photosynthetic reaction center residue M214 in the composition, absorbance properties, and conformations of H(A) and B(A) cofactors.

    Science.gov (United States)

    Saer, Rafael G; Hardjasa, Amelia; Rosell, Federico I; Mauk, A Grant; Murphy, Michael E P; Beatty, J Thomas

    2013-04-02

    In the native reaction center (RC) of Rhodobacter sphaeroides, the side chain of (M)L214 projects orthogonally toward the plane and into the center of the A branch bacteriopheophytin (BPhe) macrocycle. The possibility that this side chain is responsible for the dechelation of the central Mg(2+) of bacteriochlorophyll (BChl) was investigated by replacement of (M)214 with residues possessing small, nonpolar side chains that can neither coordinate nor block access to the central metal ion. The (M)L214 side chain was also replaced with Cys, Gln, and Asn to evaluate further the requirements for assembly of the RC with BChl in the HA pocket. Photoheterotrophic growth studies showed no difference in growth rates of the (M)214 nonpolar mutants at a low light intensity, but the growth of the amide-containing mutants was impaired. The absorbance spectra of purified RCs indicated that although absorbance changes are associated with the nonpolar mutations, the nonpolar mutant RC pigment compositions are the same as in the wild-type protein. Crystal structures of the (M)L214G, (M)L214A, and (M)L214N mutants were determined (determined to 2.2-2.85 Å resolution), confirming the presence of BPhe in the HA pocket and revealing alternative conformations of the phytyl tail of the accessory BChl in the BA site of these nonpolar mutants. Our results demonstrate that (i) BChl is converted to BPhe in a manner independent of the aliphatic side chain length of nonpolar residues replacing (M)214, (ii) BChl replaces BPhe if residue (M)214 has an amide-bearing side chain, (iii) (M)214 side chains containing sulfur are not sufficient to bind BChl in the HA pocket, and (iv) the (M)214 side chain influences the conformation of the phytyl tail of the BA BChl.

  3. Comparing the influence of selenite (Se4+) and selenate (Se6+) on the inhibition of the mercury (Hg) phytotoxicity to pak choi.

    Science.gov (United States)

    Tran, Thi Anh Thu; Dinh, Quang Toan; Cui, Zeiwei; Huang, Jie; Wang, Dan; Wei, Tianjiao; Liang, Dongli; Sun, Xin; Ning, Ping

    2018-01-01

    Selenite (Se (IV)) and selenate (Se (IV)) have recently been demonstrated to be equally effective in inhibiting mercury (Hg) phytotoxicity to plants. This assertion is still unclear. In this study, we aimed to explore the potential effects of Se species (Se 4+ and Se 6+ ) on the inhibition of the mercury (Hg) bioavailability to pak choi in dry land. Pot experiments with exposure to different dosages of mercuric chloride (HgCl 2 ) and selenite (Na 2 SeO 3 ) or selenate (Na 2 SeO 4 ) were treated. To compare the influence of Se (IV) and Se (VI) on the bioaccumulation and bioavailability of Hg, the levels of total Hg in different pak choi (Brassica chinensis L.) tissues (roots and shoots) and the distribution changes of Hg fractions in soil before planting and after harvest were determined as well as the Hg I R values in soils (relative binding intensity) were analyzed. Results showed that application Se (IV) reduced the concentrations of Hg in pak choi roots more than Se (VI). Hg concentrations were also decreased in pak choi shoots in Se (IV) treatments, while which notably increased in Se (VI) treatments. Thus, Se (IV) plays a more important role than Se (VI) in limiting the absorption and bioaccumulation of Hg in pak choi. Moreover, this inhibition may only significantly occur when Se (IV) is at an appropriate level (2.5mg/kg). In addition, the good correlations between the proportions of mobile Hg fractions (soluble and exchangeable fractions), I R values with the Hg concentrations in plants were observed. This affirmed the importance of the Hg fractions transformation and the I R indicator of Hg in the assessment of their bioavailability. Our findings regarding the importance of Se (IV) influence in reducing Hg bioaccumulation not only provided the correct appraisal about the effect of Se species on the inhibition of the Hg phytotoxicity to pak choi in dry land, but also be a good reference for selecting Se fertilizer forms (Se 4+ or Se 6+ ). Copyright © 2017

  4. Aspects épidemiocliniques et évolutifs chez 157 cas de leishmaniose cutanée au Maroc

    Science.gov (United States)

    Hjira, Naoufal; Frikh, Rachid; Marcil, Tarik; Lamsyah, Hanane; Oumakhir, Siham; Baba, Noureddine; Boui, Mohammed

    2014-01-01

    Connue au Maroc depuis la fin du XIX siècle, la leishmaniose cutanée (LC) constitue un problème de santé publique dans notre pays. Le but de notre travail est de décrire le profil épidémioclinique et l’évolution post thérapeutique chez les patients ayant une leishmaniose cutanée dans notre contexte. Nous avons effectué une étude rétrospective, basée sur l'exploitation des dossiers de malades ayant présenté une leishmaniose cutanée confirmée entre janvier 2003 et décembre 2012. Nous avons colligés 157 cas de leishmaniose cutanée. L’âge moyen des patients était de 34.5 ans avec des extrêmes de 6 ans à 63 ans. Le sex-ratio était de 2.34 H/F. La durée d’évolution moyenne des lésions était de 3,6 mois avec des extrêmes de 2 semaines à 10 mois. Les lésions étaient uniques dans 29.5% des cas. Les lésions siégeaient sur membres dans 63%. La forme ulcèro- croûteuse touchait plus de 48%. Le Glucantime était utilisé dans 29.3% des cas, l'azote liquide était utilisé chez 111 autres. L’évolution post-thérapeutique était favorable avec disparition quasi-complète des lésions dans un délai variant de 6 à 10 semaines, au prix de cicatrices inesthétiques chez 14 patients. La leishmaniose cutanée continue à poser un vrai problème de santé publique dans notre pays. L’émergence de formes sévères et résistantes à travers le monde doit inciter à multiplier et renforcer les mesures prophylactiques. PMID:25309671

  5. Optical absorption of selenite single crystals subjected to high electric fields and irradiated with X-rays or γ-rays

    International Nuclear Information System (INIS)

    Mishra, Sakuntala; Rao, A.V.K.; Rao, K.V.

    1988-01-01

    Measurements of the optical absorption coefficient of selenite single crystals show two peaks at 236 and 400 nm when plotted as a function of wavelength. These peaks decrease with increasing irradiation time for both γ and X-rays. Subsequent thermal bleaching increases the absorption coefficient at all wavelengths and flattens out the peaks at 140 0 C and 330 0 C respectively. The imposition of an a.c. or d.c. field prior to irradiation preserves the thermal bleaching characteristics with an overall increase in absorption coefficient. These effects are attributed to two different types of bond formed by water of crystallization giving rise to the two absorption peaks. Irradiation may destroy some of the bands of loosely bound water molecules near defect regions leading to a decrease in absorption. Thermal bleaching removes water molecules reducing the transparency of the samples, the more strongly bound molecules being removed at the higher temperature. Irradiation after a.c. or d.c. field treatment may introduce more defect regions enabling the removal of more water molecules by bleaching and hence increasing the absorption. (U.K.)

  6. 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.

  7. Allium cepa L. Response to Sodium Selenite (Se(IV)) Studied in Plant Roots by a LC-MS-Based Proteomic Approach.

    Science.gov (United States)

    Karasinski, Jakub; Wrobel, Kazimierz; Corrales Escobosa, Alma Rosa; Konopka, Anna; Bulska, Ewa; Wrobel, Katarzyna

    2017-05-17

    Liquid chromatography-high-resolution mass spectrometry was used for the first time to investigate the impact of Se(IV) (10 mgSe L -1 as sodium selenite) on Allium cepa L. root proteome. Using MaxQuant platform, more than 600 proteins were found; 42 were identified based on at least 2 razor + unique peptides, score > 25, and were found to be differentially expressed in the exposed versus control roots with t-test difference > ±0.70 (p roots. Different abundances of proteins involved in transcriptional regulation, protein folding/assembly, cell cycle, energy/carbohydrate metabolism, stress response, and antioxidant defense were found in the exposed vs nonexposed roots. New evidence was obtained on the alteration of sulfur metabolism due to S-Se competition in A. cepa L. which, together with the original analytical approach, is the main scientific contribution of this study. Specifically, proteins participating in assimilation and transformation of both elements were affected; formation of volatile Se compounds seemed to be favored. Changes observed in methionine cycle suggested that Se(IV) stress might repress methylation capability in A. cepa L., potentially limiting accumulation of Se in the form of nonprotein methylated species and affecting adversely transmethylation-dependent signaling pathways.

  8. Clonage de l'IGF-I et de son récepteur chez le turbot (Psetta maxima

    Directory of Open Access Journals (Sweden)

    ELIES G.

    1998-07-01

    Full Text Available Les IGF, leurs récepteurs et leurs protéines de liaison constituent une famille moléculaire qui joue un rôle essentiel dans la régulation de la croissance et du développement. Nous nous sommes intéressés à la caractérisation moléculaire de l'IGF-l et de son récepteur (IGF-1R chez le turbot (Psetta maxima, un poisson plat téléostéen. Par RT-PCR, nous avons clone un ADNc codant pour les quatre domaines de l'IGF-l mature. La protéine présente 70 à 96 % d'identité avec les autres IGF-I de vertébrés. Le clonage de la séquence codante entière du récepteur a nécessité la construction d'une banque d'ADNc d'embryons de turbots. Le récepteur est organisé en domaines dont la taille et les caractéristiques sont semblables à celles des autres récepteurs aux IGF de type 1 décrits chez les mammifères et le poulet. La région catalytique est particulièrement conservée. Dans certains domaines, notamment dans la région C-terminale du précurseur, quelques différences qui pourraient avoir une importance fonctionnelle sont cependant observées. Enfin, par RT-PCR, nous avons mis en évidence une régulation ontogénique du statut de polyadénylation des ARNm IGF-1R.

  9. Food security among individuals experiencing homelessness and mental illness in the At Home/Chez Soi Trial.

    Science.gov (United States)

    O'Campo, Patricia; Hwang, Stephen W; Gozdzik, Agnes; Schuler, Andrée; Kaufman-Shriqui, Vered; Poremski, Daniel; Lazgare, Luis Ivan Palma; Distasio, Jino; Belbraouet, Slimane; Addorisio, Sindi

    2017-08-01

    Individuals experiencing homelessness are particularly vulnerable to food insecurity. The At Home/Chez Soi study provides a unique opportunity to first examine baseline levels of food security among homeless individuals with mental illness and second to evaluate the effect of a Housing First (HF) intervention on food security in this population. At Home/Chez Soi was a 2-year randomized controlled trial comparing the effectiveness of HF compared with usual care among homeless adults with mental illness, stratified by level of need for mental health services (high or moderate). Logistic regressions tested baseline associations between food security (US Food Security Survey Module), study site, sociodemographic variables, duration of homelessness, alcohol/substance use, physical health and service utilization. Negative binomial regression determined the impact of the HF intervention on achieving levels of high or marginal food security over an 18-month follow-up period (6 to 24 months). Community settings at five Canadian sites (Moncton, Montreal, Toronto, Winnipeg and Vancouver). Homeless adults with mental illness (n 2148). Approximately 41 % of our sample reported high or marginal food security at baseline, but this figure varied with gender, age, mental health issues and substance use problems. High need participants who received HF were more likely to achieve marginal or high food security than those receiving usual care, but only at the Toronto and Moncton sites. Our large multi-site study demonstrated low levels of food security among homeless experiencing mental illness. HF showed promise for improving food security among participants with high levels of need for mental health services, with notable site differences.

  10. Dépression et niveau de fardeau chez les aidants familiaux des sujets déments en Tunisie

    Science.gov (United States)

    Ben Thabet, Jihène; Jaoua, Feriel; Charfi, Nada; Zouari, Lobna; Zouari, Nasreddine; Maalej, Mohamed

    2011-01-01

    Introduction La démence peut retentir lourdement sur les aidants familiaux du patient. Les objectifs de notre étude étaient de déterminer le niveau de fardeau et de la dépression chez les aidants familiaux de sujets déments, et d'identifier les facteurs associés à un niveau de fardeau élevé. Méthodes Il s'agissait d'une enquête auprès de 65 aidants tunisiens. Les niveaux de fardeau et de la dépression ont été évalués par, respectivement, l'inventaire de Zarit et l’échelle de Beck. Résultats Le taux des aidants qui avaient un niveau de fardeau élevé était de 52,3 %. Une dépression modérée ou sévère a été relevée chez 46,2 %. Un niveau de fardeau élevé était corrélé, du côté de l'aidant, avec le niveau socio-économique moyen à élevé, la cohabitation avec le patient, le fait d’être son conjoint, la réduction des activités quotidiennes et la sévérité de la dépression, et, du côté du dément, avec l'agressivité. Conclusion Les facteurs corrélés à un niveau de fardeau élevé orientent vers les cibles d'intervention et sont susceptibles d’être améliorés par la prise en charge, ce qui contribuerait à alléger la détresse des aidants. PMID:22384291

  11. Profiling of ornithine lipids in bacterial extracts of Rhodobacter sphaeroides by reversed-phase liquid chromatography with electrospray ionization and multistage mass spectrometry (RPLC-ESI-MS(n)).

    Science.gov (United States)

    Granafei, Sara; Losito, Ilario; Trotta, Massimo; Italiano, Francesca; de Leo, Vincenzo; Agostiano, Angela; Palmisano, Francesco; Cataldi, Tommaso R I

    2016-01-15

    Ornithine lipids (OLs), a sub-group of the large (and of emerging interest) family of lipoamino acids of bacterial origin, contain a 3-hydroxy fatty acyl chain linked via an amide bond to the α-amino group of ornithine and via an ester bond to a second fatty acyl chain. OLs in extracts of Rhodobacter sphaeroides (R. sphaeroides) were investigated by high-performance reversed phase liquid chromatography (RPLC) with electrospray ionization mass spectrometry (ESI-MS) in negative ion mode using a linear ion trap (LIT). The presence of OLs bearing both saturated (i.e, 16:0, 17:0, 18:0, 19:0 and 20:0) and unsaturated chains (i.e., 18:1, 19:1, 19:2 and 20:1) was ascertained and their identification, even for isomeric, low abundance and partially co-eluting species, was achieved by low-energy collision induced dissociation (CID) multistage mass spectrometry (MS(n), n = 2-4). OLs signatures found in two R. sphaeroides strains, i.e., wild type 2.4.1 and mutant R26, were examined and up to 16 and 17 different OL species were successfully identified, respectively. OLs in both bacterial strains were characterized by several combinations of fatty chains on ester-linked and amide-linked 3-OH fatty acids. Multistage MS spectra of monoenoic amide-linked 3-OH acyl chains, allowed the identification of positional isomer of OL containing 18:1 (i.e. 9-octadecenoic) and 20:1 (i.e. 11-eicosenoic) fatty acids. The most abundant OL ([M-H](-) at m/z 717.5) in R. sphaeroides R26 was identified as OL 3-OH 20:1/19:1 (i.e., 3-OH-eicosenoic acid amide-linked to ornithine and esterified to a nonadecenoic chain containing a cyclopropane ring). An unusual OL (m/z 689.5 for the [M-H](-) ion), most likely containing a cyclopropene ester-linked acyl chain (i.e., OL 3-OH 18:0/19:2), was retrieved only in the carotenoidless mutant strain R26. Based on the biosynthetic pathways already known for cyclopropa(e)ne ring-including acyl chains, a plausible explanation was invoked for the enzymatic

  12. Functional assignment of gene AAC16202.1 from Rhodobacter capsulatus SB1003: new insights into the bacterial SDR sorbitol dehydrogenases family.

    Science.gov (United States)

    Sola-Carvajal, Agustín; García-García, María Inmaculada; Sánchez-Carrón, Guiomar; García-Carmona, Francisco; Sánchez-Ferrer, Alvaro

    2012-11-01

    Short-chain dehydrogenases/reductases (SDR) constitute one of the largest enzyme superfamilies with over 60,000 non-redundant sequences in the database, many of which need a correct functional assignment. Among them, the gene AAC16202.1 (NCBI) from Rhodobacter capsulatus SB1003 has been assigned in Uniprot both as a sorbitol dehydrogenase (#D5AUY1) and, as an N-acetyl-d-mannosamine dehydrogenase (#O66112), both enzymes being of biotechnological interest. When the gene was overexpressed in Escherichia coli Rosetta (DE3)pLys, the purified enzyme was not active toward N-acetyl-d-mannosamine, whereas it was active toward d-sorbitol and d-fructose. However, the relative activities toward xylitol and l-iditol (0.45 and 6.9%, respectively) were low compared with that toward d-sorbitol. Thus, the enzyme could be considered sorbitol dehydrogenase (SDH) with very low activity toward xylitol, which could increase its biotechnological interest for determining sorbitol without the unspecific cross-determination of added xylitol in food and pharma compositions. The tetrameric enzyme (120 kDa) showed similar catalytic efficiency (2.2 × 10(3) M(-1) s(-1)) to other sorbitol dehydrogenases for d-sorbitol, with an optimum pH of 9.0 and an optimum temperature of 37 °C. The enzyme was also more thermostable than other reported SDH, ammonium sulfate being the best stabilizer in this respect, increasing the melting temperature (T(m)) up to 52.9 °C. The enzyme can also be considered as a new member of the Zn(2+) independent SDH family since no effect on activity was detected in the presence of divalent cations or chelating agents. Finally, its in silico analysis enabled the specific conserved sequence blocks that are the fingerprints of bacterial sorbitol dehydrogenases and mainly located at C-terminal of the protein, to be determined for the first time. This knowledge will facilitate future data curation of present databases and a better functional assignment of newly described

  13. Bioaugmentation of Lactobacillus delbrueckii ssp. bulgaricus TISTR 895 to enhance bio-hydrogen production of Rhodobacter sphaeroides KKU-PS5.

    Science.gov (United States)

    Laocharoen, Sucheera; Reungsang, Alissara; Plangklang, Pensri

    2015-01-01

    Bioaugmentation or an addition of the desired microorganisms or specialized microbial strains into the anaerobic digesters can enhance the performance of microbial community in the hydrogen production process. Most of the studies focused on a bioaugmentation of native microorganisms capable of producing hydrogen with the dark-fermentative hydrogen producers while information on bioaugmentation of purple non-sulfur photosynthetic bacteria (PNSB) with lactic acid-producing bacteria (LAB) is still limited. In our study, bioaugmentation of Rhodobacter sphaeroides KKU-PS5 with Lactobacillus delbrueckii ssp. bulgaricus TISTR 895 was conducted as a method to produce hydrogen. Unfortunately, even though well-characterized microorganisms were used in the fermentation system, a cultivation of two different organisms in the same bioreactor was still difficult because of the differences in their metabolic types, optimal conditions, and nutritional requirements. Therefore, evaluation of the physical and chemical factors affecting hydrogen production of PNSB augmented with LAB was conducted using a full factorial design followed by response surface methodology (RSM) with central composite design (CCD). A suitable LAB/PNSB ratio and initial cell concentration were found to be 1/12 (w/w) and 0.15 g/L, respectively. The optimal initial pH, light intensity, and Mo concentration obtained from RSM with CCD were 7.92, 8.37 klux and 0.44 mg/L, respectively. Under these optimal conditions, a cumulative hydrogen production of 3396 ± 66 mL H2/L, a hydrogen production rate (HPR) of 9.1 ± 0.2 mL H2/L h, and a hydrogen yield (HY) of 9.65 ± 0.23 mol H2/mol glucose were obtained. KKU-PS5 augmented with TISTR 895 produced hydrogen from glucose at a relatively high HY, 9.65 ± 0.23 mol H2/mol glucose, i.e., 80 % of the theoretical yield. The ratio of the strains TISTR 895/KKU-PS5 and their initial cell concentrations affected the rate of lactic acid production and its

  14. La double-page chez Hirohiko Araki : l’ubris faite norme

    Directory of Open Access Journals (Sweden)

    Aurélien Pigeat

    2011-03-01

    Full Text Available Le style d’Araki se caractérise par un usage massif de la double-page, loin de l’usage ponctuel que l’on trouve habituellement dans les shonen. Elle témoigne d’une forme d’ubris qui se fait norme de composition c’est-à-dire qu’elle érige le principe de débordement en règle de structuration de l’action et des planches Elle est ainsi la marque de la démesure d’un auteur qui, sous l’apparence du manga populaire, et à travers les codes de ce dernier, élabore une œuvre d’une puissance et d’une sophistication rares..

    Pour appréhender ce phénomène, il nous faut d’abord observer concrètement l’usage que fait Hirohiko Araki de la double-page, les lieux du récit que celle-ci investit, la fréquence de ses manifestations, et la manière dont elle caractérise les différentes parties de la saga Jojo’s bizarre Adventure. L’ubris de la double-page met alors particulièrement en relief deux éléments centraux de la poétique d’Hirohiko Araki : le corps et le temps.  La double-page apparaît comme la réponse matérielle à ces corps qui débordent de la page classique, qui éclatent ou se dispersent de telle sorte que l’auteur doit étendre les limites de ce cadre pour les représenter. Le temps entre lui en scène à travers le détail : la double-page devient le règne d’un détail sur lequel le lecteur passe trop vite et auquel le héros accorde toute son attention. Enfin, la double-page possède chez Hirohiko Araki une dimension proprement esthétique que révèle clairement l’usage presque absolu qui en est fait dans la septième partie de Jojo’s bizarre Adventure, Steel Ball Run, et dans le volume Rohan au Louvre, même si l’on peut la deviner déjà auparavant. La double-page est un moment où l’énigme se présente au héros, se met en mouvement ou se trouve élucidée. Le règne de l’ubris s’affirme là, dans ces doubles-pages qui n’en sont finalement plus, dans cette

  15. Les dysthyroïdies chez l’hémodialysé chronique

    Directory of Open Access Journals (Sweden)

    Najoua Zbiti

    2010-10-01

    Full Text Available INTRODUCTION: Les dysthyroïdies chez l’hémodialysé chronique sont représentées par une hypothyroïdie: dite le syndrome de basse T3, actuellement nommée "le syndrome de la maladie euthyroïdienne". L’objectif de notre travail est de déterminer le profil thyroïdien de nos HDC afin de préciser la prévalence des différents troubles thyroïdiens dans notre population et de dégager les facteurs prédictifs, aussi on a précisé l’évolution sur une période de 3 ans. METHODES: Il s’agit d’une étude rétrospective réalisée en Mars 2007 concernant 68 patients adultes en hémodialyse périodique. Nous avons analysé les paramètres anthropométriques, cliniques et biologiques. Le dosage des hormones thyroïdiennes ((triiodothyronine libre FT3, (thyroxine libre FT4 et (thyréostimuline ultra-sensible TSHus s’est effectué selon la méthode radio-immunologique. Nous avons comparé 2 groupes de patients avec et sans dysthyroïdie (définie par un taux anormal de FT3 et/ou de FT4 et/ou de TSH afin de dégager les facteurs de risque. On a réalisé une surveillance biologique des hormones thyroïdiennes pendant 3 ans afin de préciser l’incidence des différents troubles thyroïdiens dans la même population. RESULTATS: Tous les patients sont en euthyroïdie clinique. On n’a noté aucun cas de goitre. Le profil thyroïdien est caractérisé par une hypothyroïdie biologique, la prévalence était de 28%. Nous n'avons pas trouvé des cas d'hyperthyroïdie. L'étude comparative des deux groupes de malades biologiquement euthyroïdiens et hypothyroïdiens a révèle le syndrome inflammatoire (p=0.001, l’âge avancé (p=0.003, et la durée prolongée en hémodialyse (p=0.04 comme des facteurs de risque liés à l’hypothyroïdie biologique. Deux HDC ont nécessité un traitement hormonal substitutif vu le contexte du diabète dans un cas et de la grossesse dans l’autre cas. Le suivi biologique pendant trois ans n’a r

  16. Comparaison de différentes associations d'anticoagulants sur les numérations plaquettaires et la formation d'agrégats chez le chat

    OpenAIRE

    Charru, Pauline

    2011-01-01

    Chez le chat, l'hémogramme est un examen complémentaire parfois difficile à interpréter aux vues des nombreuses difficultés d'ordre pré-analytique et analytique potentielle. Parmi elles, on retiendra la forte tendance des plaquettes à s'agréger in vitro, surtout sur EDTA-dépendante, une nouvelle molécule antiagrégante a montré son intérêt : le CTAD (Citrate, Théophylline, Adénosine et Dipyridamole). Dans notre étude, l'utilisation de l'association EDTA et CTAD chez 46 chats sains, en éliminan...

  17. Etude de l'effet du stress salin (NaCl) chez deux variétés de tomate ...

    African Journals Online (AJOL)

    La germination, les paramètres de croissance ainsi que les paramètres biochimiques, sont comparés chez deux variétés de tomate (Campbell 33 et Mongal) soumises à des concentrations croissantes de NaCl. (0,17, 50, 85 et 130 mM). Le pourcentage de germination des graines diminue avec l'augmentation de la salinité ...

  18. Activité antérieure – Le chômage chez les jeunes, un problème d ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    7 juil. 2016 ... Gordon Betcherman, professeur à l'École de développement international et mondialisation de l'Université d'Ottawa et coauteur du Rapport sur le développement dans le monde 2013 : Emplois publié par la Banque mondiale, a évoqué la nécessité d'enrichir les connaissances au sujet du chômage chez ...

  19. Apport des approches inspirées de la neuropsychologie au diagnostic d'autisme chez l'adulte: une étude de cas

    OpenAIRE

    Weiner , L.; Baratta , A.; Henry , J.; Di Santi , C.

    2010-01-01

    Resume Nous allons illustrer a partir d?un cas clinique les procedures diagnostiques des troubles du spectre autistique chez l?adulte, inspirees des theories neurocognitives actuelles. Nous relatons le cas d?un homme de 29 ans recu en consultation psychiatrique. Le diagnostic initialement retenu etait celui de personnalite evitante, compliquee de phobie sociale et d?un trouble depressif intercurrent. Malgre la diminution des symptomes anxieux et depressifs apres l?instauration d?un...

  20. Iconicity and Typography in Steve McCaffery’s Panel-Poems Iconicité et typographie chez Steve McCaffery: les poèmes-panneaux

    Directory of Open Access Journals (Sweden)

    Fiona McMahon

    2007-01-01

    Full Text Available Cet article se propose de retracer les étapes d’un projet d’écriture qui se rattache historiquement aux mouvances internationales de la poésie concrète comme à l’émergence d’une poétique de l’iconicité chez l’avant-garde nord-américaine du vingtième siècle. Le matérialisme dont se réclame la poésie de Steve McCaffery se traduit dans son œuvre typographique Carnival (1967-75 par une pratique mettant en jeu la lettre, le plus petit dénominateur de la langue, et la page, qui doit se laisser transformer pour que se réalise un nouvel espace de signification poétique. Le dialogue qui se joue entre le lisible et le visible prend forme grâce à un répertoire de techniques expérimenté avec la machine à écrire et de concert avec le lecteur, devenu acteur de l’œuvre poétique. La pratique architecturale du poème-panneau chez McCaffery sera envisagée dans son rapport actuel avec le prolongement des problématiques de la poésie visuelle chez l’avant-garde nord-américaine.

  1. EXAFS and FTIR studies of selenite and selenate sorption by alkoxide-free sol–gel generated Mg–Al–CO 3 layered double hydroxide with very labile interlayer anions

    KAUST Repository

    Chubar, Natalia

    2014-01-01

    © the Partner Organisations 2014. Current research on Layered Double Hydroxides (LDHs, also known as hydrotalcites, HTs) is predominantly focused on their intercalations, but the industrial application of LDHs for anion exchange adsorption has not yet been achieved. It was recently recognized that, to develop LDH applications, these materials should be produced using methods other than direct co-precipitation. Mg-Al-CO3LDH produced using an alkoxide-free sol-gel synthesis showed exceptional removal properties for aqueous selenium species. Se K-edge EXAFS/XANES and FTIR studies (supporting the data by XRD patterns) were performed to explain the unusual adsorptive performance of Mg-Al LDH by revealing the molecular-level mechanism of HSeO3 -, SeO4 2-and {HSeO3 -+ SeO4 2-} uptake at pH 5, 7 and 8.5. The role of inner-sphere complexation (exhibited by inorganic adsorbents with good performance) in adsorption of both selenium aqueous species was not confirmed. However, Mg-Al LDH fully met the other expectations regarding the involvement of the interlayer anions. The interlayer carbonate (due to its favorable speciation and generous HT hydration) gave a "second breath" to selenite sorption and was the only mechanism that controlled the removal of Se(vi). Because inner sphere complexation was the leading mechanism for selenite removal, ion exchange via surface OH-and interlayer CO3 2-species was the only mechanism for selenate removal; both of these species were easily bound to Mg-Al LDH (on its surface and gently parked into the interlayer forming a multilayer without violation of the structure of Mg-Al-CO3LDH). This work provides the first theoretical explanation of why it is more difficult to sorb selenate than selenite and which material should be used for this purpose. This journal is

  2. EXAFS and FTIR studies of selenite and selenate sorption by alkoxide-free sol–gel generated Mg–Al–CO 3 layered double hydroxide with very labile interlayer anions

    KAUST Repository

    Chubar, Natalia

    2014-08-08

    © the Partner Organisations 2014. Current research on Layered Double Hydroxides (LDHs, also known as hydrotalcites, HTs) is predominantly focused on their intercalations, but the industrial application of LDHs for anion exchange adsorption has not yet been achieved. It was recently recognized that, to develop LDH applications, these materials should be produced using methods other than direct co-precipitation. Mg-Al-CO3LDH produced using an alkoxide-free sol-gel synthesis showed exceptional removal properties for aqueous selenium species. Se K-edge EXAFS/XANES and FTIR studies (supporting the data by XRD patterns) were performed to explain the unusual adsorptive performance of Mg-Al LDH by revealing the molecular-level mechanism of HSeO3 -, SeO4 2-and {HSeO3 -+ SeO4 2-} uptake at pH 5, 7 and 8.5. The role of inner-sphere complexation (exhibited by inorganic adsorbents with good performance) in adsorption of both selenium aqueous species was not confirmed. However, Mg-Al LDH fully met the other expectations regarding the involvement of the interlayer anions. The interlayer carbonate (due to its favorable speciation and generous HT hydration) gave a "second breath" to selenite sorption and was the only mechanism that controlled the removal of Se(vi). Because inner sphere complexation was the leading mechanism for selenite removal, ion exchange via surface OH-and interlayer CO3 2-species was the only mechanism for selenate removal; both of these species were easily bound to Mg-Al LDH (on its surface and gently parked into the interlayer forming a multilayer without violation of the structure of Mg-Al-CO3LDH). This work provides the first theoretical explanation of why it is more difficult to sorb selenate than selenite and which material should be used for this purpose. This journal is

  3. FTIR spectroscopic studies of selenite reduction by cells of the rhizobacterium Azospirillum brasilense Sp7 and the formation of selenium nanoparticles

    Science.gov (United States)

    Kamnev, Alexander A.; Mamchenkova, Polina V.; Dyatlova, Yulia A.; Tugarova, Anna V.

    2017-07-01

    Microbially driven reduction of selenium oxyanions to elementary selenium, often in the form of nanoparticles (NPs), is widespread in nature. A diversity of possible applications of such biogenic NPs, including those in nanobiotechnology, as well as the specificity of methodologies and mechanisms of their formation via ;green synthesis; are very attractive features justifying further studies of the processes of selenium oxyanion bioreduction and the resulting Se0 nanostructures. In this study, live biomass of the rhizobacterium Azospirillum brasilense Sp7 (harvested after the logarithmic growth phase and washed from culture medium components) was used to obtain extracellular Se NPs relatively homogeneous in size (with average diameters within 50-100 nm) in the process of selenite reduction. Both the control cultures of A. brasilense Sp7 and those incubated with SeO32- (producing Se NPs), as well as the resulting separated Se NPs were studied using Fourier transform infrared (FTIR) spectroscopy in the transmission mode (measured as dried layers on a ZnSe disc), in addition to transmission electron microscopy (TEM), to compare metabolic changes in cells and the bioorganic layers associated with the Se NPs. In the control culture (stored for 24 h in physiological saline), FTIR spectroscopic signs of poly-3-hydroxybutyrate (a 'reserve' biopolyester) were observed as a response to the lack of nutrients (trophic stress), whereas they were virtually absent in cells incubated for 24 h in physiological saline with 10 mM SeO32- (toxicity stress). FTIR spectra of Se NPs separated from bacterial cells showed bands typical of proteins, polysaccharides and lipids associated with the particles (in line with their TEM images showing a thin layer over the NPs), in addition to strong carboxylate bands, which evidently stabilise the NP structure and morphology.

  4. LD/sub 50/ and selenium concentration in organs of rabbit following oral application of sodium selenite and toxicity verification of Ursoselevit-Praemix

    Energy Technology Data Exchange (ETDEWEB)

    Berschneider, F.; Hess, M.; Neuffer, K.; Willer, S.

    1976-07-01

    LC/sub 50/24 hr/ was established in the first of a series of experiments on 72 rabbits for orally applied sodium selenite. The dosage was 8.62 mg/kg live weight, the confidence interval being (1 - ..cap alpha.. = 0.95) +/- 0.13 mg/kg. The value was four times as high following intravenous application. Complete lethality was recorded from 15 mg Na/sub 2/SeO/sub 3//kg live weight within 21 hours. Thirty-six animals were involved in the second experiment of the series. They had 50 or 100 percent Ursoselevit-Praemix (30 ppm Se) in their rations. Body mass development of the test animals was superior to that recorded from the controls in the first 50 days, after which limit the former declined strongly in a few days. Their general condition worsened. Postmortem finding, following slaughter, included catarrhal enteritis, toxic liver dystrophy, scattered pulpous tumors in the spleen, and interstitial nephritis. In the third experiment (50 percent Ursoselevit-Praemix with 60 ppm Se in the rations), the test animals developed better than the controls during the first two months, after which point they exhibited the same clinical symptoms as those observed in the second experiment, stopped putting on weight, and eventually turned cachectic. The pathomorphological findings were identical with those obtained from the second experiment. The selenium concentrations in the organs of the test animals all were much higher than those of the controls. Their amounts in excess to base values were up to eleven times in the blood, nine times in the liver, twelve times in the kidneys, and 13 times in the muscles. 11 references, 2 figures, 2 tables.

  5. Engineering of a calcium-ion binding site into the RC-LH1-PufX complex of Rhodobacter sphaeroides to enable ion-dependent spectral red-shifting.

    Science.gov (United States)

    Swainsbury, David J K; Martin, Elizabeth C; Vasilev, Cvetelin; Parkes-Loach, Pamela S; Loach, Paul A; Neil Hunter, C

    2017-11-01

    The reaction centre-light harvesting 1 (RC-LH1) complex of Thermochromatium (Tch.) tepidum has a unique calcium-ion binding site that enhances thermal stability and red-shifts the absorption of LH1 from 880nm to 915nm in the presence of calcium-ions. The LH1 antenna of mesophilic species of phototrophic bacteria such as Rhodobacter (Rba.) sphaeroides does not possess such properties. We have engineered calcium-ion binding into the LH1 antenna of Rba. sphaeroides by progressively modifying the native LH1 polypeptides with sequences from Tch. tepidum. We show that acquisition of the C-terminal domains from LH1 α and β of Tch. tepidum is sufficient to activate calcium-ion binding and the extent of red-shifting increases with the proportion of Tch. tepidum sequence incorporated. However, full exchange of the LH1 polypeptides with those of Tch. tepidum results in misassembled core complexes. Isolated α and β polypeptides from our most successful mutant were reconstituted in vitro with BChl a to form an LH1-type complex, which was stabilised 3-fold by calcium-ions. Additionally, carotenoid specificity was changed from spheroidene found in Rba. sphaeroides to spirilloxanthin found in Tch. tepidum, with the latter enhancing in vitro formation of LH1. These data show that the C-terminal LH1 α/β domains of Tch. tepidum behave autonomously, and are able to transmit calcium-ion induced conformational changes to BChls bound to the rest of a foreign antenna complex. Thus, elements of foreign antenna complexes, such as calcium-ion binding and blue/red switching of absorption, can be ported into Rhodobacter sphaeroides using careful design processes. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  6. Profil épidémiologique des pathologies respiratoires chez l’enfant à l’Hôpital d’Enfants de Rabat, Maroc

    Science.gov (United States)

    Benchekroun, Ilham; Boubkraoui, Mohamed El Mahdi; Mekaoui, Nour; Karboubi, Lamia; Mahraoui, Chafiq; Dakhama, Badr Sououd Benjelloun

    2017-01-01

    Introduction Les pathologies respiratoires représentent un motif fréquent d'hospitalisation en pédiatrie. L'objectif de cette étude était d'évaluer le profil épidémiologique des pathologies respiratoires chez l'enfant à l'hôpital d'enfants de Rabat, Maroc. Méthodes Il s'agit d'une étude observationnelle transversale qui a concerné tous les cas d'enfants âgés de 3 mois à 15 ans hospitalisés pour une pathologie respiratoire au service de pneumoallergologie et infectiologie pédiatriques de l'hôpital d'enfants de Rabat sur une période d'une année, du 1 janvier 2014 au 31 décembre 2014. Résultats Sur 3537 patients hospitalisés, 2493 (70,5%) l'ont été pour une pathologie respiratoire. Les hospitalisations pour exacerbation d'asthme (p < 0,001), bronchiolite aigüe (p < 0,001) et dyspnée laryngée (p = 0,004) étaient plus fréquentes chez le garçon alors que les hospitalisations pour pneumopathie aigüe (p = 0,005), pour inhalation de corps étranger (p = 0,007) et pour coqueluche (p = 0,020) étaient plus fréquentes chez la fille. Les hospitalisations pour pneumopathie aigüe (p < 0,001), exacerbation de séquelles graves de virose (p < 0,001) et pour coqueluche (p < 0,001) étaient plus fréquentes chez le nourrisson. Les hospitalisations pour pneumopathie aigüe (p < 0,001) et pour coqueluche (p = 0,015) étaient plus fréquentes en période automnohivernale. Conclusion Les motifs d'hospitalisation étaient dominés par les exacerbations d'asthme et la bronchiolite aigüe, lesquelles étaient plus fréquentes chez le garçon. Les infections respiratoires, représentées par les pneumopathies aigües et la coqueluche, étaient plus fréquentes en période automnohivernale et touchaient plus le nourrisson. PMID:29675122

  7. Structure and function of cytochrome c2 in electron transfer complexes with the photosynthetic reaction center of Rhodobacter sphaeroides: optical linear dichroism and EPR.

    Science.gov (United States)

    Drepper, F; Mathis, P

    1997-02-11

    The photosynthetic reaction center (RC) and its secondary electron donor the water-soluble cytochrome (cyt) c2 from the purple bacterium Rhodobacter sphaeroides have been used in cross-linked and non-cross-linked complexes, oriented in compressed gels or partially dried multilayers, to study the respective orientation of the primary donor P (BChl dimer) and of cyt c2. Three methods were used: (i) Polarized optical absorption spectra at 295 and 10 K were measured and the linear dichroism of the two individual transitions (Qx, Qy), which are nearly degenerate within the alpha-band of reduced cyt c2, was determined. Attribution of the polarization directions to the molecular axes within the heme plane yielded the average cyt orientation in the complexes. (ii) Time-resolved flash absorption measurements using polarized light allowed determination of the orientation of cyt c2 in complexes which differ in their kinetics of electron transfer. (iii) EPR spectroscopy of ferricyt c2 in cross-linked RC-cyt c2 complexes was used to determine the angle between the heme and the membrane plane. The results suggest the following structural properties for the docking of cyt c2 to the RC: (i) In cross-linked complexes, the two cytochromes displaying half-lives of 0.7 and 60 micros for electron transfer to P+ are similarly oriented (difference plane is parallel to the symmetry axis of the RC (0 degrees +/- 10 degrees). Moreover, the Qy transition, which is assumed to be polarized within the ring III-ring I direction of the heme plane, makes an angle of 56 degrees +/- 1 degree with the symmetry axis. (iii) The dichroism spectrum for the fast phase (0.7 micros) for the non-cross-linked cyt c2-RC complex suggests an orientation similar to that of cross-linked cyt c2, but the heme plane is tilted about 20 degrees closer to the membrane. An alternative model is that two or more bound states of cyt c2 with heme plane tilt angles between 0 degrees and 30 degrees allow the fast electron

  8. Synthesis and crystal structure of a new neodymium(III) selenate-selenite: Nd2(SeO4)(SeO3)2(H2O)2

    International Nuclear Information System (INIS)

    Feng Meiling; Mao Jianggao

    2005-01-01

    The title new neodymium(III) selenate-selenite was obtained by hydrothermal reactions of neodymium(III) oxide, H 2 SeO 4 and 1,10-phenanthroline at 140 o C. Its structure was established by single-crystal X-ray diffraction. The title compound crystallizes in the monoclinic space group C2/c with cell parameters of a = 12.258(2) A, b 7.1024(15) A, c = 13.391(3) A, β = 104.250(2) o . The structure of Nd 2 (SeO 4 )(SeO 3 ) 2 (H 2 O) 2 is isomorphous with that of Er 2 (SeO 4 )(SeO 3 ) 2 (H 2 O) 2 , which was refined in the monoclinic space group C2 with the disordered selenate group. It features an ordered 3D network with channels along b-axis. The selenate or selenite groups alone can form a 2D layer with the Nd(III) ions. IR spectrum, TGA and luminescent studies have also been performed

  9. The synthesis and crystal structures of the first rare-earth alkaline-earth selenite chlorides MNd10(SeO3)12Cl8 (M=Ca and Sr)

    International Nuclear Information System (INIS)

    Berdonosov, P.S.; Olenev, A.V.; Dolgikh, V.A.; Lightfoot, P.

    2007-01-01

    Two new alkaline-earth Nd selenite chlorides MNd 10 (SeO 3 ) 12 Cl 8 (M=Ca, Sr) were obtained using crystal growth from alkaline-earth chloride melts in quartz tubes. These new compounds crystallize in the orthorhombic system in space group C cca (no. 68). The compounds were studied by energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction. It was shown that both compounds adopt the same structure type, constructed by complex [M 11 (SeO 3 ) 12 ] 8+ slabs separated by chloride anion layers perpendicular to the longest cell parameter. The SeO 3 groups show a pyramidal shape and may be described as SeO 3 E tetrahedra. Such SeO 3 groups decorate the Nd-O skeletons forming the [M 11 (SeO 3 ) 12 ] 8+ slabs. - Graphical abstract: Two new alkaline-earth Nd selenite chlorides MNd 10 (SeO 3 ) 12 Cl 8 (M=Ca, Sr) were synthesized. These structures are constructed by [M 11 (SeO 3 ) 12 ] 8+ slabs separated by chloride anion layers

  10. Bases mécanistiques des effets d'un insecticide agrovétérinaire, le fipronil,et/ou de ses métabolites sur la fonction thyroîdienne chez le rat

    OpenAIRE

    Roques, Béatrice

    2012-01-01

    Le fipronil, insecticide largement utilisé, est un perturbateur thyroïdien chez le rat modulant le catabolisme hépatique des hormones thyroïdiennes. Ses effets chez le mouton, considéré comme un modèle plus pertinent que le rat pour étudier une régulation de la fonction thyroïdienne chez l'Homme, sont plus limités. Le but de cette thèse était de caractériser au niveau hépatique le mode d'action du fipronil sur la fonction thyroïdienne en s'intéressant 1) au rôle potentiel du principal métabol...

  11. Cerebral Scintigraphy in the Child and Nursing Infant; La Scintigraphie Cerebrale chez l'Enfant et le Nourrisson

    Energy Technology Data Exchange (ETDEWEB)

    Akerman, M.; Rougerie, J.; Guiot, G. [INSERM, Hopital Foch, Suresnes (France)

    1969-05-15

    overall results of cerebral scintigraphy are less favourable in the case of cerebral tumours in children than in that of adults. The reason for this is the high frequency in children of tumours of the brain stem, the pituitary and the third ventricle, the detectability of which is low. However, very good results were obtained in the case of 35 tumours of the cerebellum and the fourth ventricle as a result of using very rigorous techniques. Excellent results have also been obtained with other surgical lesions, such as chronic subdural haematoma in the nursing infant and vascular malformations. In conditions not amenable to neurosurgery definitely false results were the exception. Lastly, the authors present the initial results of a study of the cerebral cisterns and ventricles. They emphasize the abundance of information supplied by these scintigraphic methods and their great utility for the neurosurgeon. (author) [French] La scintigraphie cerebrale chez l' enfant a fait l'objet de peu de travaux publies. Une etude separee chez l' enfant se justifie cependant par les particularites de la pathologie neurochirurgicale infantile. L' exploration de l' enfant et du nourrisson conduit a discuter les donnees dosimetriques et a poser le probleme de la detectabilite des tumeurs de la fosse posterieure, des tumeurs medianes de la base du crane, et des astrocytomes, qui sont justement les tumeurs les plus frequentes en pathologie infantile. Enfin, l' enfant et le nourrisson sont les sujets d'application privilegies des techniques de scintigraphie apres injection locale de composes radioactifs, par voie sous- arachno'idienne, intra-ventriculaire, ou intra-cavitaire, pour 1' etude des hydrocephalies communicantes ou par stenose, des malformations meningo-encephaliques et des hematomes sous-duraux chroniques. En cinq ans ont ete explores 400 enfants et nourrissons ages de 2 mois a 16 ans, soit 10% des 4000 explorations craniennes effectuees dans le laboratoire des auteurs. Parmi ces

  12. Systeme microfluidique d'analyse sanguine en temps reel pour l'imagerie moleculaire chez le petit animal

    Science.gov (United States)

    Convert, Laurence

    De nouveaux radiotraceurs sont continuellement développés pour améliorer l'efficacité diagnostique en imagerie moléculaire, principalement en tomographie d'émission par positrons (TEP) et en tomographie d'émission monophotonique (TEM) dans les domaines de l'oncologie, de la cardiologie et de la neurologie. Avant de pouvoir être utilisés chez les humains, ces radiotraceurs doivent être caractérisés chez les petits animaux, principalement les rats et les souris. Pour cela, de nombreux échantillons sanguins doivent être prélevés et analysés (mesure de radioactivité, séparation de plasma, séparation d'espèces chimiques), ce qui représente un défi majeur chez les rongeurs à cause de leur très faible volume sanguin (˜1,4 ml pour une souris). Des solutions fournissant une analyse partielle sont présentées dans la littérature, mais aucune ne permet d'effectuer toutes les opérations dans un même système. Les présents travaux de recherche s'insèrent dans le contexte global d'un projet visant à développer un système microfluidique d'analyse sanguine complète en temps réel pour la caractérisation des nouveaux radiotraceurs TEP et TEM. Un cahier des charges a tout d'abord été établi et a permis de fixer des critères quantitatifs et qualitatifs à respecter pour chacune des fonctions de la puce. La fonction de détection microfluidique a ensuite été développée. Un état de l'art des travaux ayant déjà combiné la microfluidique et la détection de radioactivité a permis de souligner qu'aucune solution existante ne répondait aux critères du projet. Parmi les différentes technologies disponibles, des microcanaux en résine KMPR fabriqués sur des détecteurs semiconducteurs de type p-i-n ont été identifiés comme une solution technologique pour le projet. Des détecteurs p-i-n ont ensuite été fabriqués en utilisant un procédé standard. Les performances encourageantes obtenues ont mené à initier un projet de ma

  13. Comparative study of DL-selenomethionine vs sodium selenite and seleno-yeast on antioxidant activity and selenium status in laying hens.

    Science.gov (United States)

    Jing, C L; Dong, X F; Wang, Z M; Liu, S; Tong, J M

    2015-05-01

    The aim of this study was to compare the effect of DL-selenomethionine (SM) with 2 routinely used Se sources, sodium selenite (SS) and seleno-yeast (SY), on relative bioavailability based on antioxidant activity and tissue Se content. Six hundred thirty 131-day-old brown laying hens were randomly assigned to 7 treatments for 168 d (24 wks) with 6 replicates of 15 hens per replicate. The SS and SY animals were supplemented a cornmeal and soybean diet that supplied a total Se 0.3 mg/kg whereas SM was added at 4 different levels to the total Se at 0.1, 0.3, 0.5 and 0.7 mg/kg. All hens fed the Se-supplemented diet showed higher glutathione peroxidase (GSH-Px) activity (P < 0.01), higher superoxide dismutase (SOD) activity (P < 0.05), lower malondialdehyde (MDA) content (P < 0.05) in plasma, and greater Se contents in egg yolks, albumen, leg muscle, breast muscle, liver, and plasma compared with those fed the control diet (P < 0.01). The organic sources (SY and SM) exhibited a greater ability to increase the GSH-Px activity (P < 0.01) and Se content in albumen (P < 0.01), leg, and breast muscles (P = 0.0099 and P = 0.0014, respectively) than the SS that was added at 0.3 mg Se/kg. The higher SM added levels increased the GSH-Px activity until the dose of 0.5mg Se/kg (P < 0.01).The greater Se concentrations in albumen, muscle and liver appeared in the higher SM-added level, as well as above the dose of 0.1 mg Se/kg (P < 0.01). In addition, hens fed the diet with SM accumulated more Se in albumen, leg, and breast muscle than those fed diets with SY (P < 0.05). These results confirmed the higher ability of organic Se sources to increase the antioxidant activity and Se deposition in egg albumen, leg, and breast muscles compared with SS, and demonstrated a significantly better efficiency of SM compared with SY for albumen and muscle Se enrichment. © 2015 Poultry Science Association Inc.

  14. Ctenophthalmus (Ethioctenophthalmus kemmelberg n. sp. (Insecta : Siphonaptera : Ctenophthalmidae, Puce nouvelle de Tanzanie et description de structures internes non signalées chez les Mécoptèroïdes

    Directory of Open Access Journals (Sweden)

    Laudisoit A.

    2007-09-01

    Full Text Available Nous avons récemment décrit deux taxa nouveaux de Siphonaptères (Ctenophthalmus (Ethioctenophthalmus teucqae teucqae et C. (E. teucqae shumeensis Laudisoit & Beaucournu, 2007 du foyer pesteux de Lushoto (Monts Usambara occidentaux, Tanzanie. Nous étudierons ici un taxon nouveau, Ctenophthalmus kemmelberg, puce originale, non seulement par ses segments génitaux, mais aussi par des structures jusqu’à maintenant décrites, à notre connaissance, chez aucun Mécoptèroïde. Elles sont observables chez les femelles uniquement. Nous proposons d’attribuer à ces structures remarquables le nom d’“organes de Teucq”.

  15. Les tumeurs neuro ectodermiques périphériques primitives de localisation thoracique (tumeur d'Askin) chez l'adulte jeune : à propos de deux observations, revue de la littérature

    OpenAIRE

    Brugger , Catherine

    2003-01-01

    Non disponible / Not available; La tumeur d'Askin appartient à la famille des tumeurs neuro ectodermiques périphériques primitives. De localisation thoracique, elle est décrite initialement chez l'enfant, sa survenue chez l'adulte jeune demeure exceptionnelle. Elle est définie comme une tumeur maligne à petites cellules rondes exprimant le gène MIC2 et présentant une translocation chromosomique t(11,22) spécifique. Ses aspects cliniques et radiologiques ne sont pas spécifiques. L'évolution à ...

  16. Distribution épidémiologique de l'infection à VIH chez les femmes enceintes dans les dix régions du Cameroun et implications stratégiques pour les programmes de prévention

    Science.gov (United States)

    Billong, Serge-Clotaire; Fokam, Joseph; Billong, Edson-Joan; Nguefack-Tsague, Georges; Essi, Marie-Josée; Fodjo, Raoul; Sosso, Samuel-Martin; Gomba, Armelle; Mosoko-Jembia, Joseph; Loni-Ekali, Gabriel; Colizzi, Vittorio; Bissek, Anne-Cécile Zoung-Kani; Monebenimp, Francisca; Nfetam, Jean-Bosco Elat

    2015-01-01

    Introduction Le Cameroun se situe dans un contexte d’épidémie généralisée du VIH. La sous-population des femmes enceintes, facilement accessible au sein de la population générale, représente une cible probante pour mener la surveillance du VIH et estimer l’évolution épidémiologique. L'objectif de notre étude était d’évaluer la distribution épidémiologique du VIH chez les femmes enceintes. Méthodes Étude transversale menée en 2012 chez 6521 femmes enceintes (49,3% âgées de 15-24 ans) en première consultation prénatale (CPN1) dans 60 sites des 10 régions Camerounaises. L'algorithme en série a été utilisé pour le sérodiagnostic du VIH. Résultats La prévalence du VIH était de 7,8% (508/6521), avec une différence non significative (p = 0,297) entre milieu rural (7,4%) et milieu urbain (8,1%). En zone rurale, cette prévalence variait de 0,7% à l'Extrême-Nord à 11,8% au Sud. Cependant, en zone urbaine elle variait de 4% à l'Ouest à 11,1% au Sud-Ouest. Suivant l’âge, la prévalence était plus élevée (11,3%) chez les femmes de 35-39 ans. Suivant le niveau de scolarisation, la prévalence du VIH était plus faible (4,4%) chez celles non-scolarisées, et plus élevée (9,3%) chez celles ayant un niveau primaire. Selon la profession, l'infection était plus élevée chez les coiffeuses (15,5%), secrétaires (14,8%), commerçantes (12,9%) et institutrices/enseignantes (10,8%). Conclusion La prévalence du VIH reste élevée chez les femmes enceintes au Cameroun, sans distinction entre milieux rural et urbain. Les stratégies de prévention devraient s'orienter préférentiellement chez les femmes enceintes âgées, celles du niveau d'instruction primaire, et celles du secteur des petites et moyennes entreprises. PMID:26090037

  17. Prévalence de l'hépatite B chez les personnes infectées par le VIH à ...

    African Journals Online (AJOL)

    Introduction: la co-infection avec l'hépatite B est l'un des défis majeurs de la prise en charge du VIH depuis l'amélioration de l'accès aux antirétroviraux en Afrique. La présente étude visait à estimer la prévalence de l'hépatite B chez les personnes séropositives au VIH à Parakou et décrire les facteurs associés. Méthodes: il ...

  18. Carence en fer, anémie et anémie ferriprive chez les donneurs de sang à Kinshasa, République Démocratique du Congo

    Science.gov (United States)

    Nzengu-Lukusa, Franck; Yuma-Ramazani, Sylvain; Sokolua-Mvika, Eddy; Dilu-Keti, Angèle; Malenga-Nkanga, Blanchard; Shuli, Jean Baptiste; Nzongola-Nkasu, Donatien Kayembe; Mbayo-Kalumbu, Ferdinand; Ahuka-Mundeke, Steve

    2016-01-01

    Introduction En République Démocratique du Congo (RDC), plus d'un million de don de sang ont été réalisés entre 2007 et 2011. Cependant, aucun bilan portant sur la carence en fer et l'anémie ferriprive, conséquence d'un don de sang chez les donneurs de sang (DS), n'est disponible dans ce pays. L'objectif de cette étude était d'estimer la prévalence de la carence en fer, de l'anémie et de l'anémie ferriprive chezles DS au Centre National de Transfusion Sanguine (CNTS) à Kinshasa en RDC. Méthodes Entre Décembre 2012 et Août 2013, une étude transversale a été menée au CNTS où des DS éligibles au don de sang ont été inclus. Les informations socio démographiques et des prélèvements sanguins ont été collectés de manière simultanée au don de sang. La ferritine sérique a été dosée pour évaluer la carence en fer en utilisant la technique ELISA. L'hémogramme a été réalisé en vue d’évaluer et mettre au point l'anémie. Résultats Au total 386 DS ont été inclus dans cette étude. La prévalence de la carence en fer et de l'anémie ferriprive étaient respectivement de 63,2% (244/386) et 25,9% (100/386) des DS. Une anémie a été trouvée chez 36.5% (141/386) au moment du don de sang. Conclusion La carence en fer, l'anémie et l'anémie ferriprive demeurent très fréquentes chez les DS à Kinshasa. Ces résultats suggèrent la révision des tests biologiques utilisés dans le recrutement des DS au CNTS. Par ailleurs le dosage de la ferritine s'impose en routine chez les DS rég PMID:27303590

  19. Anomalies échocardiographiques chez l'hémodialysé chronique: prévalence et facteurs de risqué

    OpenAIRE

    Ezziani, Mariam; Najdi, Adil; Mikou, Souad; Elhassani, Anis; Akrichi, Mohammed Amine; Hanin, Hakim; Arrayhani, Mohammed; Houssaini, Tarik Sqalli

    2014-01-01

    Introduction Les complications cardio-vasculaires sont la principale cause de mortalité et de morbidité chez les patients hémodialysés chroniques. Le but de cette étude est de décrire les différentes atteintes cardiaques à l’échocardiographie transthoracique et de dégager les facteurs associés aux principales atteintes. Méthodes Etude transversale monocentrique incluant des patients adultes hémodialysés depuis plus d'un an et ayant bénéficié d'une échocardiographie transthoracique durant l'an...

  20. La pharmacothérapie du délirium chez les patients atteints de cancer avancé : une étude descriptive

    OpenAIRE

    Rousseau, Mayssa

    2010-01-01

    Les objectifs de la recherche étaient de décrire prospectivement les comportements de prescriptions des médecins spécialistes en soins palliatifs suivant un delirium diagnostiqué chez les patients atteints de cancer avancé et d'évaluer la conformité de ces médecins aux recommandations pharmacologiques pour le traitement du delirium. Les antipsychotiques, les benzodiazepines, les corticostéroïdes et les opioïdes sont les classes thérapeutiques qui ont été retenues et analysées. L'effectif réel...

  1. CONTRIBUTION À L’ÉTUDE DES LIPIDES TISSULAIRES ET PLASMATIQUES CHEZ LE RAT WISTAR MÂLE SOUS RÉGIME HYPERGRAS

    OpenAIRE

    BENSALAH, Meryem

    2012-01-01

    De nos jours, les pathologies associées aux accumulations lipidiques dans l’organisme humain, telle l’obésité, prennent une importance croissante dans les questions de santé. Ces maladies sont consécutives à des apports caloriques superieurs à la dépense énergétique aboutissant à un surplus de stockage des graisses. L’objectif principal de cette étude était d’évaluer l’impact d’un régime hyperlipidique hypercalorique administré pour une période de 8 semaines chez le rat male Wistar (que nous ...

  2. Invention et interprétation : chants de boisson et chants chamaniques chez les Suruí du Rondônia

    OpenAIRE

    Yvinec, Cédric

    2014-01-01

    Invention et interprétation : chants de boisson et chants chamaniques chez les Suruí du Rondônia. Cet article examine les techniques rhétoriques mises en œuvre par deux genres de chants rituels des Suruí du Rondônia, chants de fête de boisson et chants chamaniques, notamment les écarts par lesquels la langue et l’énonciation rituelles se distinguent du discours ordinaire. Ces procédés rhétoriques trouvent un écho au niveau sociologique, à travers le statut du chamane et celui du grand homme d...

  3. IST-06 - Réémergence de la syphilis chez les personnes infectées par le VIH en Martinique en 2015

    OpenAIRE

    Putot , Alain; Rozé , Benoit; Pierre-François , Sandrine; Pircher , M.; Vilain , R.; Miossec , C.; Desbois , N.; Hochedez , Patrick; Abel , Sylvie; Cabié , André

    2016-01-01

    National audience; En 2004 a débuté une épidémie de syphilis en Martinique chez les hommes ayant des rapports sexuels avec des hommes (HSH) et vivant avec le VIH, pour se généraliser secondairement à l’ensemble des groupes à risque. L’objectif de cette étude était d’estimer l’évolution, depuis 2005, de l’incidence et des caractéristiques des cas de syphilis récente dans la cohortede patients vivant avec le VIH (PVVIH) suivis en Martinique.

  4. Traitements didactiques preventifs d'un type de conceptions erronees en sciences physiques chez des eleves du secondaire

    Science.gov (United States)

    Blondin, Andre

    Dans un contexte constructiviste, les connaissances anterieures d'un individu sont essentielles a la construction de nouvelles connaissances. Quelle qu'en soit la source (certaines de ces connaissances ont ete elaborees en classe, d'autres ont ete elaborees par interaction personnelle de l'individu avec son environnement physique et social), ces connaissances, une fois acquises, constituent les matieres premieres de l'elaboration des nouvelles conceptions de cet individu. Generalement, cette influence est consideree comme positive. Cependant, dans un milieu scolaire ou l'apprentissage de certaines conceptions enchassees dans un programme d'etudes et enterinees par l'ensemble d'une communaute est obligatoire, certaines connaissances anterieures peuvent entraver la construction des conceptions exigees par la communaute. La litterature abonde de tels exemples. Cependant, certaines connaissances anterieures, en soi tout a fait conformes a l'Heritage, peuvent aussi, parce qu'utilisees de facon non pertinente, entraver la construction d'une conception exigee par la communaute. Ici, la litterature nous donne peu d'exemples de ce type, mais nous en fournirons quelques-uns dans le cadre theorique, et ce sera un d'entre eux qui servira de base a nos propos. En effet, une grande proportion d'eleves inscrits a un cours de sciences physiques de la quatrieme secondaire, en reponse a un probleme deja solutionne durant l'annee et redonne lors d'un examen sommatif, "Pourquoi la Lune nous montre-t-elle toujours la meme face?", attribue principalement la cause de ce phenomene a la rotation de la Terre sur son axe. En tant que responsable de l'enseignement de ce programme d'etudes, plusieurs questions nous sont venues a l'esprit, entre autres, comment, dans un contexte constructiviste, est-il possible de reduire chez un eleve, l'impact de cette connaissance anterieure dans l'elaboration de la solution et ainsi prevenir la construction d'une conception erronee? Nous avons teste nos

  5. Solid-state synthesis, structure and properties of a novel open-framework cadmium selenite bromide: [Cd10(SeO3)8Br4]·HBr·H2O

    International Nuclear Information System (INIS)

    Chen, Wen-Tong; Wang, Ming-Sheng; Wang, Guan-E; Chen, Hui-Fen; Guo, Guo-Cong

    2013-01-01

    A novel open-framework cadmium selenite bromide, [Cd 10 (SeO 3 ) 8 Br 4 ]·HBr·H 2 O (1), has been obtained by a solid-state reaction at 450 °C, and the structure has been determined by single-crystal X-ray diffraction analysis. Compound 1 crystallizes in Pbcm of the orthorhombic system: a=10.882(3), b=16.275(5), c=18.728(6) Å, V=3317(2) Å 3 , R1/wR2=0.0411/0.0659. Compound 1 is characteristic of a novel 3-D open-framework structure, composing ∞ 2 [CdSeO 3 ] layers and the pillars of edge-shared CdO 3 Br 2 square pyramids. The lattice water molecules and the HBr molecules locate in the voids of the framework. Optical absorption spectrum of 1 reveals the presence of an optical gap of 1.65 eV. Solid-state photoluminescent study indicates that compound 1 exhibits strong violet emission. TG–DSC measurement shows that compound 1 is thermally stable up to 200 °C. - Graphical abstract: A metal selenite halide has been synthesized and features a 3-D open-framework structure, composing edge-shared CdO 8 decahedra and pillars of edge-sharing pentahedra. UV–vis, TG–DSC and luminescent measurements are also reported. Highlights: • This paper reports a novel cadmium selenite bromide obtained by an intermediate-temperature solid-state reaction. • The title compound is characteristic of a novel 3-D open-framework structure, composing ∞ 2 [CdSeO 3 ] layers and the pillars of edge-shared CdO 3 Br 2 square pyramids. • The title compound is thermally stable up to 200 °C. • The title compound has an optical gap of 1.65 eV and exhibits strong violet emission

  6. Effect of dietary selenium and vitamin E on the ultrastructure and ATP concentration of boar spermatozoa, and the efficacy of added sodium selenite in extended semen on sperm motility.

    Science.gov (United States)

    Marin-Guzman, J; Mahan, D C; Whitmoyer, R

    2000-06-01

    Three experiments evaluated the effects of dietary Se and vitamin E on the ultrastructure of spermatozoa, ATP concentration of spermatozoa, and the effects of adding sodium selenite to semen extenders on subsequent sperm motility. The experiment was a 2 x 2 arrangement of treatments in a randomized complete block design. A total of 10 mature boars were fed from weaning to 18 mo of age diets fortified with two levels of supplemental Se (0 or .5 ppm) or vitamin E (0 or 220 IU/kg diet). The nonfortified diets contained .06 ppm Se and 4.4 IU vitamin E/kg. In Exp. 1, the spermatozoa from all boars were examined by electron microscopy. Vitamin E had no effect on structural abnormalities in the spermatozoa. When the low-Se diet was fed the acrosome or nuclei of the spermatozoa was unaffected, but the mitochondria in the tail midpiece were more oval with wider gaps between organelles. The plasma membrane connection to the tail midpiece was not tightly bound as when boars were fed Se. Immature spermatozoa with cytoplasmic droplets were more numerous when boars were fed the low-Se diet, but the occurrence of midpiece abnormalities occurred in boars fed diets with or without Se or vitamin E. Our results suggest that Se may enhance spermatozoa maturation in the epididymis and may reduce the number of sperm with cytoplasmic droplets. In Exp. 2, the concentration of ATP in the spermatozoa was evaluated in the semen of all treatment boars. When the low-Se diet was fed, ATP concentration was lower (P boar semen with a semen extender with sodium selenite added at 0, .3, .6, or .9 ppm Se. Three ejaculates from each boar were used to evaluate these effects on sperm motility to 48 h after dilution. Sperm motility declined (P extender, and this decline was exacerbated as the concentration of added Se increased (P boars resulted in abnormal spermatozoal mitochondria, a lower ATP concentration in the spermatozoa, and a loose apposition of the plasma membrane to the helical coil of the

  7. Les discussions reprennent chez Gate Gourmet CONFLIT. Les negociations pour une nouvelle CCT se derouleront sous l'égide de la Chambre genevoise des relations collectives de travail

    CERN Multimedia

    Mutter, F

    2003-01-01

    "Dialogue renoue chez Gate Gourmet a Geneve...cela serait la seconde fois seulement que la CRCT agirait de la sorte. L'unique precedent remonte a un different opposant le CERN à certains de ses employes" (1/2 page).

  8. Métabolisme du méthanol chez les micro-organismes méthylotrophes Metabolism of Methanol in Methylotrophic Microorganisms (Bibliographic Review

    Directory of Open Access Journals (Sweden)

    Ballerini D.

    2006-11-01

    Full Text Available De nombreux travaux portant sur l'étude du métabolisme du méthanol chez les bactéries et les levures ont été publiés depuis la fin des années cinquante, et nous permettent d'avoir une meilleure connaissance des mécanismes d'assimilation de ce substrat par les micro-organismes. Cet article précise l'état actuel des connaissances acquises sur les mécanismes d'oxydation du méthanol et sur les deux voies biosynthétiques différentes, la voie sérine et le cycle des ribose-phosphates, trouvées chez les micro-organismes capables d'une croissance méthylotrophique. A great mony research reports on studies of the methanol metabolism in bacteria and yeast has been published since the end of the 1950s and give us a better understanding of the mechanisms by which this substrate is assimulated by microorganisms. This article reviéws the state-of-the-art of knowledge about methanol oxidation mechanisms and two different biosynthesis procedures, 1. e.the serine one and the cycle of the ribose-phosphates found in microorganisms capable of methylotrophic growth.

  9. Synthesis, structure, and characterization of two new bismuth(III) selenite/tellurite nitrates: [(Bi3O2)(SeO3)2](NO3) and [Bi(TeO3)](NO3)

    Science.gov (United States)

    Meng, Chang-Yu; Wei, Ming-Fang; Geng, Lei; Hu, Pei-Qing; Yu, Meng-Xia; Cheng, Wen-Dan

    2016-07-01

    Two new bismuth(III) selenite/tellurite nitrates, [(Bi3O2)(SeO3)2](NO3) and [Bi(TeO3)](NO3), have been synthesized by conventional facile hydrothermal method at middle temperature 200 °C and characterized by single-crystal X-ray diffraction, powder diffraction, UV-vis-NIR optical absorption spectrum, infrared spectrum and thermal analylsis. Both [(Bi3O2)(SeO3)2](NO3) and [Bi(TeO3)](NO3) crystallize in the monoclinic centronsymmetric space group P21/c with a=9.9403(4) Å, b=9.6857(4) Å, c=10.6864(5) Å, β=93.1150(10)° for [(Bi3O2)(SeO3)2](NO3) and a=8.1489(3) Å, b=9.0663(4) Å, c=7.4729(3) Å, β=114.899(2)° for Bi(TeO3)(NO3), respectively. The two compounds, whose structures are composed of three different asymmetric building units, exhibit two different types of structures. The structure of [(Bi3O2)(SeO3)2](NO3) features a three-dimensional (3D) bismuth(III) selenite cationic tunnel structure [(Bi3O2)(SeO3)2] 3∞ with NO3- anion group filling in the 1D tunnel along b axis. The structure of [Bi(TeO3)](NO3) features 2D bismuth(III) tellurite [Bi(TeO3)2]2∞ layers separated by NO3- anion groups. The results of optical diffuse-reflectance spectrum measurements and electronic structure calculations based on density functional theory methods show that the two compounds are wide band-gap semiconductors.

  10. Elimination of polarity in the carotenoid terminus promotes the exposure of B850-binding sites (Tyr 44, 45) and ANS-mediated energy transfer in LH2 complexes of Rhodobacter sphaeroides.

    Science.gov (United States)

    Liu, Yuan; Wu, Yongqiang; Xu, Chunhe

    2004-12-10

    Carotenoids in the peripheral light-harvesting complexes (LH2) of the green mutant (GM309) of Rhodobacter sphaeroides were identified as containing neurosporenes, which lack the polar CH(3)O group, compared to spheroidenes in native-LH2 of R. sphaeroides 601. After LH2 complexes were treated with 1-anilino-8-naphthalene sulfonate (ANS), new energy transfer pathways from ANS or tryptophan to carotenoids were discovered in both native- and GM309-LH2. The carotenoid fluorescence intensity of GM309-LH2 was greater than that of native-LH2 when bound with ANS, suggesting that the elimination of polarity in the neurosporene increases the energy transfer from ANS to carotenoid. The fact that two alpha-tyrosines (alpha-Tyr 44, 45, B850-binding sites) in each alpha-apoprotein of GM309-LH2 were more easily modified than those of native-LH2 by N-acetylimidazole (NAI) indicates that the elimination of polarity in the neurosporene terminus increases the exposure of these sites to solution.

  11. Effect of co-substrate on production of poly-β- hydroxybutyrate (PHB and copolymer PHBV from newly identified mutant Rhodobacter sphaeroides U7 cultivated under aerobic-dark condition

    Directory of Open Access Journals (Sweden)

    Kemarajt Kemavongse

    2007-07-01

    Full Text Available Photosynthetic bacterial mutant strain U7 was identified using both classical and molecular (16S rDNA techniques to be Rhodobacter sphaeroides. The glutamate-acetate (GA medium containing sodium acetate and sodium glutamate as carbon and nitrogen sources was used for production of poly-β-hydroxybutyrate (PHB from R. sphaeroides U7 cultivated under aerobic-dark condition (200 rpm at 37oC. Effect of auxiliary carbon sources (propionate and valerate and concentrations (molar ratio of 40/0, 40/20, 40/40 and 40/80 on copolymer production were studied. Both combinations of acetate with valerate and acetate with propionate were found to induce the accumulation of poly-β-hydroxybutyrate-co-β-hydroxyvalerate (PHBV within the cell. Acetate with propionate in the molar ratio of 40/40 gave the highest poly-β-hydroxyalkanoates (PHA content (77.68%, followed by acetate with valerate at the same molar ratio (77.42%. Although their polymer contents were similar, the presence of 40 mM valerate gave more than 4 times higher hydroxyvalerate (HV fraction (84.77% than in the presence of 40 mM propionate (19.12% HV fraction.

  12. Les séquelles de brûlures cervicocéphaliques chez l’enfant

    Science.gov (United States)

    Sankale, A.A.; Ndiaye, A.; Ndoye, A.; Ndiaye, L.; Ndoye, M.

    2011-01-01

    Summary La peau, barrière protectrice de l’organisme, est très exposée aux agressions et donc aux brûlures. Le but de ce travail est d’apprécier les particularités des séquelles de brûlure cervicofaciales chez l’enfant en milieu sub-saharien et d’évaluer leur prise en charge. Il s’agit d’une étude rétrospective réalisée dans le service de Chirurgie Pédiatrique du Centre Hospitalo-universitaire Aristide Le Dantec de Dakar (Sénégal). Vingt-sept dossiers de patients ont été colligés entre mai 2001 et avril 2008. L’âge moyen lors de la consultation était de 6,7 ans et le sex ratio m:f de 1,7:1. La topographie des séquelles se répartit ainsi: la face (66,7%), le cou (29,6%) et le cuir chevelu (11,1%). Concernant le type de séquelles, les brides prédominaient (33,3%), suivies des cicatrices chéloïdiennes ou hypertrophiques (25,9%), des ectropions de paupières (18,5%), des alopécies du cuir chevelu (11,1%), des ulcérations chroniques (7,4%) et de dyschromie (3,7%). Le traitement a été chirurgical dans 55,7% des cas: plasties en Z suivies ou non d’une greffe de peau pour les brides et libération de bride suivie d’une greffe pour les ectropions de paupières. Pour ce qui concerne les patients opérés, la morbidité opératoire a été de 20% et la mortalité opératoire nulle. Les cicatrices chéloïdiennes ont fait l’objet d’un traitement médical par infiltrations de dermocorticoïdes. Au-delà de l’urgence, les brûlures cervicofaciales de l’enfant entraînent un préjudice esthétique et fonctionnel important. L’amélioration de leur pronostic passe par la qualité des premiers soins et par la sensibilisation des parents aux risques d’accidents domestiques. PMID:21991239

  13. « Ces animaux qu’on appelle hommes ». Animalité et monstruosité chez Cyrano et Foigny

    Directory of Open Access Journals (Sweden)

    Alex Bellemare

    2015-12-01

    Full Text Available Au dix-septième siècle, la querelle de la « nouvelle philosophie », qui oppose Descartes à Gassendi, repose notamment sur la question, polémique, de la différenciation entre l’homme et l’animal. En effet, toute définition de l’animal engage aussi et parallèlement une réflexion sur l’homme. Les répercussions de ce débat philosophique s’observent dans la littérature viatique au sens large, mais plus particulièrement dans sa variante libertine et antichrétienne. En misant sur l’indécision formelle du genre viatique, qui oscille entre fiction romanesque et réalité testimoniale, les récits de voyage libertins tirent philosophiquement profit du principe relativiste que le genre impose par définition. Or, la médiation de l’inconnu par le connu se manifeste de manière encore plus brutale lorsque le voyage s’effectue dans l’ailleurs utopique. De la même façon que le récit de voyage met à distance la culture du voyageur entrant en contact avec celle de l’autre, le discours sur l’animal reflète également le discours sur soi. Dans l’Autre monde (1657 de Cyrano de Bergerac et la Terre australe connue (1676 de Gabriel de Foigny, deux romans hybrides qui mêlent récits de voyage et discours utopique, la frontière qui sépare ontologiquement l’homme de la bête s’atténue et se trouble. En souterrain, toute une anthropologie libertine s’esquisse chez Cyrano et Foigny, qui correspond à une expression singulière du « moi ».

  14. Les accidents de la vie courante chez l’enfant à Dakar: à propos de 201 cas

    Science.gov (United States)

    Mohamed, Azhar Salim; Sagna, Aloïse; Fall, Mbaye; Ndoye, Ndeye Aby; Mbaye, Papa Alassane; Fall, Aimé Lakh; Diaby, Alou; Ndour, Oumar; Ngom, Gabriel

    2017-01-01

    Les accidents de la vie courante (AcVC) sont fréquents chez l’enfant et peuvent être à l’origine de lésions handicapantes et de décès. L’objectif de notre travail était d’étudier les aspects épidémiologiques et lésionnels des AcVC à Dakar. C’est une étude transversale descriptive menée du 1er Janvier 2013 au 30 juin 2013. Les enfants victimes d’accidents domestiques, d’accidents de sport et de loisirs ou d’accidents scolaires ont été inclus. Nous avons étudié des paramètres généraux et des paramètres ayant trait à chaque type d’AcVC. Deux cent et un enfants ont été inclus, ce qui représentait 27% des consultations aux urgences. Il y avait 148 garçons et 53 filles. Les enfants de moins de 5 ans étaient les plus touchés (37,8%). Le football et le jeu de lutte étaient les grands pourvoyeurs d’AcVC. Les AcVC survenaient principalement à domicile (58,2%) et dans les aires de sport et de loisirs (31,8%). Les fractures prédominaient dans les différents types d’AcVC: 54,9% des accidents domestiques, 68,8% des accidents de sport et de loisirs et 40% des accidents scolaires. Au plan épidémiologique, nos résultats sont superposables à la littérature. Les fractures prédominent à l’opposé de la littérature où les contusions sont prépondérantes. Le jeu de lutte est le plus grand pourvoyeur de ces fractures après le football. La connaissance des aspects épidémiologiques et lésionnels permet de mener des campagnes de prévention des AcVC à Dakar. PMID:29187941

  15. Séroprévalence de l’AgHBs chez la femme enceinte dans le centre du Maroc

    Science.gov (United States)

    Sbiti, Mohammed; Khalki, Hanane; Benbella, Imane; louzi, Lhoussaine

    2016-01-01

    La transmission materno-fœtale du virus de l'hépatite B (VHB) est un problème qui préoccupe toujours les autorités sanitaires à travers le monde et suscite la mise en place de mesures préventives renforcées. Le statut réplicatif du virus chez la mère séropositive, évalué par la positivité de l'AgHbe et le taux de la charge virale, conditionne le risque de contamination qui est plus important en période péri-natale. Les mères porteuses chroniques du VHB constituent un véritable réservoir de la transmission verticale de cette infection. Nous avons étudié, à travers cette enquête sur 1120 femmes enceintes Marocaines, la séroprévalence de l'AgHBs qui était de 2,35%, dans le but d'alimenter les données nationales sur ce sujet. Parmi ces femmes séropositives pour l'AgHBs, 79,1% avaient un AgHBe négatif et ont bénéficié d'une recherche moléculaire qui s'est révélée positive dans 89,4% des cas. La vaccination de la femme en âge de procréer est l'un des piliers majeurs de la prévention de la transmission verticale du VHB, seulement 2,4% de nos patientes étaient vaccinées. Ceci relève l'intérêt du dépistage au cours de la grossesse, qui doit se focaliser sur la sensibilisation à la vaccination de femmes séronégatives, et le suivi par biologie moléculaire des mères séropositives dans le but d'instaurer un traitement prophylactique adéquat. PMID:27795784

  16. Le cancer différencié de la thyroïde chez l’enfant et l’adolescent: à propos de 22 cas

    Science.gov (United States)

    Anajar, Said; Tatari, Mohammed; Lakhbal, Adil; Abada, Reda; Rouadi, Sami; Roubal, Mohammed; Mahtar, Mohammed

    2017-01-01

    L’obectif était de mettre en relief les particularités du cancer de la thyroïde chez l’enfant et l’adolescent, et d’évaluer nos résultats par rapport à la littérature internationale a travers une série de cas la plus représentatif au Maroc: 22 cas. C'est une étude rétrospective descriptive des patients atteints de cancer différencié de la thyroïde, hospitalisés au service d’ORL et de Chirurgie Cervico-faciale de L’hopital 20 Août de Casablanca-Maroc, sur la période qui s’étend de Janvier 1995 à Mars 2015. Nous avons recueilli les données relatives à 22 cas, qui répondaient à nos critères d’inclusion. L’âge moyen de nos patients était de 14 ans, avec une sex-ratio 3,4, la plupart de nos patients ont consulté pour un nodule thyroïdien, associé dans 22,7% des cas à une adénopathie cervicale, et dans 9,1% à des signes de compression. L’ensemble des patients ont bénéficié d’une thyroïdectomie totale, suivie d’un curage ganglionnaire dans 31,82%. Le diagnostic de cancer thyroïdien a reposé sur l’examen anatomopathologique de la pièce opératoire, qui a objectivé un carcinome papillaire dans 95,4% des cas, et un carcinome vésiculaire dans 4,5%. Le traitement par l’iode radioactif 131 a été réalisé dans 100% des cas. Par la suite tous nos patients ont été mis sous hormonothérapie thyroïdienne. Une surveillance étroite et régulière a permis de détecter des métastases ganglionnaires chez 3 patients, et les métastases à distance chez 4 patients. Le cancer différencié de la thyroïde de l’enfant et l’adolescent est une entité rare mais agressive, son traitement se base sur la chirurgie, associée à l’irathérapie donnant un pronostic excellent. PMID:29255541

  17. Prévalence de l'hépatite B chez les personnes infectées par le VIH à Parakou au Bénin

    Science.gov (United States)

    Dovonou, Comlan Albert; Amidou, Salimanou Ariyoh; Kpangon, Amadohoué Arsène; Traoré, Yacoubou Adam; Godjedo, Togbemabou Primous Martial; Satondji, Assongba Joseph; Wachinou, Ablo Prudence; Issa-Djibril, Fatioulaye Mahamadi; Fourn, Léonard; Zannou, Djimon Marcel; Gandaho, Prosper

    2015-01-01

    Introduction La co-infection avec l'hépatite B est l'un des défis majeurs de la prise en charge du VIH depuis l'amélioration de l'accès aux antirétroviraux en Afrique. La présente étude visait à estimer la prévalence de l'hépatite B chez les personnes séropositives au VIH à Parakou et décrire les facteurs associés. Méthodes Il s'agit d'une étude transversale menée de Mai 2011 à Juin 2012 dans le service de Médecine du CHU de Parakou. Ont été inclus tous les adultes séropositifs au VIH vus en consultation ou hospitalisés. Les données ont été collectées par interviews et dépouillement de dossiers médicaux. L'antigène HBs a été recherché par un test rapide et l'ALAT a été dosé. L'analyse des données a été faite avec le logiciel EpiInfo 3.5.1. Les proportions ont été comparées grâce au test de Chi-deux ou au test de Fisher au seuil de significativité de 5%. Un modèle de régression logistique multivariable a permis d'expliquer la prévalence de l'hépatite B. Résultats Sur les 744 sujets inclus on a dénombré 555 femmes. L’âge moyen était de 35,5 + 10,1 ans. La prévalence de l'hépatite B a été estimée à 16,9% (IC95: 14,3%-19,9%). Cette prévalence était plus élevée chez les sujets originaires du Borgou/Alibori et ceux au stade 4 de l'OMS. Conclusion La prévalence de la co-infection VIH/VHB au CHU Parakou est élevée. Le dispositif national de prise en charge et de prévention de l'hépatite B chez les personnes séropositives au VIH doit être renforcé. PMID:26097629

  18. La prévention et le traitement des infections bactériennes chez les enfants aspléniques ou hypospléniques

    Science.gov (United States)

    1999-01-01

    L’asplénie, qu’elle soit fonctionnelle ou anatomique, s’associe à un accroissement du risque d’infection potentiellement fatale ou constituant un danger de septicémie postsplénectomie (SPS). En raison du risque accru de bactériémie par des bactéries encapsulées chez les enfants aspléniques, la vaccination visant à prévenir une infection au Streptococcus pneumoniae, à l’Haemophilus influenzae de type b (Hib) et au Neiserria meningitidis est recommandée. Malgré la prévalence croissante de S pneumoniae pénicillinorésistant, on recommande aussi l’usage de pénicilline prophylactique chez les enfants aspléniques de moins de cinq ans, et pendant au moins un an après une splénectomie. La poursuite de la prophylaxie antibiotique après cette période dépend de la situation clinique de chaque enfant et de la prévalence de S pneumoniae pénicillinorésistant au sein de la collectivité. Lorsque des enfants aspléniques font de la fièvre ou présentent des symptômes non spécifiques, ils devraient faire l’objet d’une évaluation immédiate. Si on présume la présence de septicémie bactérienne, il faut procéder à une analyse du sang et des autres liquides organiques pertinents et entreprendre sur-le-champ une antibiothérapie à large spectre par voie parentérale, laquelle doit agir également contre les souches de S pneumoniae présentes dans la collectivité. Chez les enfants aspléniques souffrant d’une septicémie foudroyante à S pneumoniae, le taux de mortalité est élevé, malgré l’utilisation rapide d’une antibiothérapie convenable, d’où l’importance des mesures préventives.

  19. Pharmacothérapie de la dépression chez les aînés

    Science.gov (United States)

    Frank, Christopher

    2014-01-01

    Résumé Objectif Discuter du traitement pharmacologique de la dépression chez les personnes âgées, y compris le choix des antidépresseurs, le titrage de la dose, la surveillance de la réponse et des effets secondaires et le traitement des cas réfractaires. Sources des données Les lignes directrices de 2006 de la Canadian Coalition for Seniors’ Mental Health sur l’évaluation et le traitement de la dépression ont servi comme source principale. Pour recenser les articles publiés après les lignes directrices, on a procédé à une recherche documentaire dans MEDLINE de 2007 à 2012 à l’aide des expressions en anglais depression, treatment, drug therapy et elderly. Message principal Le but du traitement devrait être la rémission des symptômes. L’amélioration des symptômes peut être surveillée en fonction des objectifs du patient qu’on a identifiés ou en se servant d’outils cliniques comme le Patient Health Questionnaire–9. On devrait envisager le traitement en 3 étapes: l’étape du traitement aigu pour obtenir la rémission des symptômes, une étape de continuation pour prévenir la récurrence d’un même épisode de la maladie (rechute) et une étape de maintien (prophylaxie) pour prévenir de futurs épisodes (récurrence). Le dosage initial devrait être la moitié de la dose de départ habituelle chez l’adulte et il devrait être titré régulièrement jusqu’à ce que le patient réponde, jusqu’à ce que la dose maximale soit atteinte ou encore que les effets secondaires en limitent l’augmentation. Parmi les effets secondaires fréquents, on peut mentionner les chutes, la nausée, les étourdissements, les céphalées et, moins communément, l’hyponatrémie et des changements dans l’intervalle QT. Des stratégies pour changer ou augmenter les antidépresseurs sont présentées. Les patients plus âgés devraient être traités pendant au moins un an à compter de l’observation d’une amélioration clinique et

  20. Ksenia Pimenova, Les sources de savoirs. Le renouveau du bouddhisme et du chamanisme chez les Touvas de la Sibérie du Sud

    OpenAIRE

    Pimenova, Ksenia

    2013-01-01

    Cette thèse présente une étude comparative du « renouveau » post-soviétique du chamanisme et du bouddhisme tibétain (école Guélougpa) chez les Touvas, un des peuples autochtones de la Sibérie du Sud (Russie). Ce phénomène a lieu après des décennies de politique antireligieuse (dès la fin des années 1920 jusqu’aux années 1980) ayant abouti à la destruction de la communauté bouddhique et à la marginalisation du chamanisme. Nous analysons le chamanisme et le bouddhisme post-soviétiques comme deu...

  1. La lipogenèse chez le lapin. Importance pour le contrôle de la teneur en lipides de la viande

    OpenAIRE

    Gondret, Florence

    1999-01-01

    La teneur en lipides d’un tissu est la résultante de plusieurs flux métaboliques (dépôt, synthèse, utilisation). Cet article présente les principales caractéristiques de la synthèse des lipides chez le lapin, dans le muscle comparativement aux tissus adipeux visibles et au foie. Le potentiel de synthèse de novo exprimé par le muscle augmente avec l’âge de l’animal, en parallèle à l’accumulation des triglycérides dans les adipocytes intramusculaires. L’activité des enzymes qui fournissent le N...

  2. La face cachée de l’ancestralité. Masques et affinité chez les Matis d’Amazonie brésilienne

    OpenAIRE

    Erikson, Philippe

    2009-01-01

    La face cachée de l’ancestralité. Masques et affinité chez les Matis d’Amazonie brésilienne. Cet article montre en quoi les masques matis sont révélateurs des conceptions ouest amazoniennes de la temporalité et de la succession des générations. Après une discussion sur l’aspect cérémoniel des mascarades et sur les caractéristiques ontologiques imputées aux esprits mariwin, ce texte soutient que ces derniers, bien qu’associés aux morts du groupe et à des valeurs endogènes, représentent des aff...

  3. Le soi et l’estime de soi chez l’enfant: Une revue systématique de la littérature

    OpenAIRE

    Pinto, Alexandra Maria Pereira Inácio Sequeira; Gatinho, Ana Rita dos Santos; Tereno, Susana; Veríssimo, Manuela

    2016-01-01

    Cette étude vise : a) à analyser les différentes méthodes utilisées pour l’étude du Soi et chez les enfants, en ce que concerne sa qualité et son potentiel et b) à synthétiser les résultats déjà obtenus en termes de Soi/d’estime de soi/d’autoconcept, pour les enfants en âge préscolaire. Après avoir établi des critères rigoureux d’inclusion et d’exclusion, 33 articles ont été sélectionnés, dans plusieurs bases de données, nationales et international...

  4. L'acquisition et la construction de la notion de temps chez les enfants de 5 à 9 ans: perspective développementale

    OpenAIRE

    De Coster, Lotta

    2004-01-01

    Cette recherche porte sur l’acquisition et la construction de la notion de temps chez les enfants de 5 à 9 ans, c’est-à-dire ceux qui fréquentent des classes allant de la 3e maternelle à la 3e année primaire. Dans la partie théorique nous analysons les différentes notions constitutives qui caractérisent le temps :l’ordre de succession, la durée, le cycle, l’irréversibilité, l’horizon temporel. Nous nous intéressons également aux notions linguistiques ainsi qu’aux notions associées telles que ...

  5. Jeux et enjeux d’écriture chez Chrétien de Troyes: l’exemple de «Cligès»

    Directory of Open Access Journals (Sweden)

    Ida Lucia Machado

    2011-10-01

    Full Text Available Neste artigo, nos propomos descrever a estética da trama irônica presente na escritura de Chrétien de Troyes, tomando por base seu romance Cligès. A destacar algumas estratégias passíveis de criar o fenômeno irônico, estaremos também mostrando o poder de sedução que emana desta escritura.Nous nous proposons, dans cet artible, de décrire l’esthétique du jeu ironique chez Chrétien de Troyes, em puisant dans son roman Cligès. Enn dégageant qulques unes dês stratégies susceptibles de créer le phénomène ironique, nous montrerons, à la fois, le pouvoir de séduction qui emane de cette écriture.

  6. Three new d10 transition metal selenites containing PO4 tetrahedron: Cd7(HPO4)2(PO4)2(SeO3)2, Cd6(PO4)1.34(SeO3)4.66 and Zn3(HPO4)(SeO3)2(H2O)

    Science.gov (United States)

    Ma, Yun-Xiang; Gong, Ya-Ping; Hu, Chun-li; Mao, Jiang-Gao; Kong, Fang

    2018-06-01

    Three new d10 transition metal selenites containing PO4 tetrahedron, namely, Cd7(HPO4)2(PO4)2(SeO3)2 (1), Cd6(PO4)1.34(SeO3)4.66 (2) and Zn3(HPO4)(SeO3)2(H2O) (3), have been synthesized by hydrothermal reaction. They feature three different structural types. Compound 1 exhibits a novel 3D network composed of 3D cadmium selenite open framework with phosphate groups filled in the 1D helical tunnels. The structure of compound 2 displays a new 3D framework consisted of 2D cadmium oxide layers bridged by SeO3 and PO4 groups. Compound 3 is isostructural with the reported solids of Co3(SeO3)3-x(PO3OH)x(H2O) when x is equal to 1.0. Its structure could be viewed as a 3D zinc oxide open skeleton with SeO3 and HPO4 polyhedra attached on the wall of the tunnels. They represent the only examples in metal selenite phosphates in addition to the above cobalt compounds. Optical diffuse reflectance spectra revealed that these solids are insulators, which are consistent with the results of band structure computations based on DFT algorithm.

  7. Validation de la version francophone d’une échelle composite multidimensionnelle pour l’évaluation de la douleur postopératoire chez les chats

    Science.gov (United States)

    Steagall, Paulo V.M.; Monteiro, Beatriz P.; Lavoie, Anne-Marie; Frank, Diane; Troncy, Eric; Luna, Stelio P.L.; Brondani, Juliana T.

    2017-01-01

    Résumé L’objectif de cette étude était de valider la version francophone de l’échelle composite multidimensionnelle de douleur UNESP-Botucatu (MCPS-Fr) chez les chats. Deux vétérinaires et une étudiante de médecine vétérinaire francophones ont identifié trois catégories de comportements distincts sur des vidéos : «les changements psychomoteurs», «la protection de la région douloureuse» et «les variables physiologiques». La cohérence interne était excellente (score total du coefficient alpha de Cronbach était de 0,94; 0,90; et 0,61, respectivement). La bonne concordance entre les évaluations à l’aveugle des observateurs et l’évaluateur de référence confirme la validité de cet instrument. La fiabilité inter- et intra-évaluateur était bonne à très bonne. Le point limite optimal pour l’analgésie de secours, identifié avec une courbe ROC, était au-delà de 7 (échelle allant de 0 à 30 points), avec une sensibilité de 97,8 % et une spécificité de 99,1 %. La MCPS-Fr est un outil valide et sensible pour l’évaluation de la douleur aiguë chez les chattes ayant subi une ovariohystérectomie. PMID:28042156

  8. Role of PufX protein in photosynthetic growth of Rhodobacter sphaeroides. 1. PufX is required for efficient light-driven electron transfer and photophosphorylation under anaerobic conditions.

    Science.gov (United States)

    Barz, W P; Francia, F; Venturoli, G; Melandri, B A; Verméglio, A; Oesterhelt, D

    1995-11-21

    The pufX gene is essential for photoheterotrophic growth of the purple bacterium Rhodobacter sphaeroides. In order to analyze the molecular function of the PufX membrane protein, we constructed a chromosomal pufX deletion mutant and phenotypically compared it to a pufX+ control strain and to two suppressor mutants which are able to grow photosynthetically in the absence of pufX. Using this genetic background, we confirmed that PufX is required for photoheterotrophic growth under anaerobic conditions, although all components of the photosynthetic apparatus were present in similar amounts in all strains investigated. We show that the deletion of PufX is not lethal for illuminated pufX- cells, suggesting that PufX is required for photosynthetic cell division. Since chromatophores isolated from the pufX- mutant were found to be unsealed vesicles, the role of PufX in photosynthetic energy transduction was studied in vivo. We show that PufX is essential for light-induced ATP synthesis (photophosphorylation) in anaerobically incubated cells. Measurements of absorption changes induced by a single turnover flash demonstrated that PufX is not required for electron flow through the reaction center and the cytochrome bc1 complex under anaerobic conditions. During prolonged illumination, however, PufX is essential for the generation of a sufficiently large membrane potential to allow photosynthetic growth. These in vivo results demonstrate that under anaerobic conditions PufX plays an essential role in facilitating effective interaction of the components of the photosynthetic apparatus.

  9. L’évaluation du risque cardiaque avant l’utilisation de stimulants chez les enfants et les adolescents

    Science.gov (United States)

    Bélanger, SA; Warren, AE; Hamilton, RM; Gray, C; Gow, RM; Sanatani, S; Côté, J-M; Lougheed, J; LeBlanc, J; Martin, S; Miles, B; Mitchell, C; Gorman, DA; Weiss, M; Schachar, R

    2009-01-01

    Les décisions en matière de réglementation et les documents scientifiques au sujet de la prise en charge du trouble de déficit de l’attention avec hyperactivité (TDAH) soulèvent des questions quant à l’innocuité des médicaments et à l’évaluation convenable à effectuer avant le traitement afin de déterminer la pertinence d’une pharmacothérapie. Ce constat est particulièrement vrai en présence de cardiopathies structurelles ou fonctionnelles. Le présent article contient l’analyse des données disponibles, y compris les publications révisées par des pairs, des données tirées du site Web de la Food and Drug Administration des États-Unis au sujet des réactions indésirables déclarées chez des enfants qui prennent des stimulants, ainsi que des données de Santé Canada sur le même problème. Des lignes directrices consensuelles sur l’évaluation pertinente sont proposées d’après l’apport des membres de la Société canadienne de pédiatrie, de la Société canadienne de cardiologie et de l’Académie canadienne de psychiatrie de l’enfant et de l’adolescent, qui possèdent notamment des compétences et des connaissances précises tant dans le secteur du TDAH que de la cardiologie pédiatrique. Le présent document de principes prône une anamnèse et un examen physique détaillés avant la prescription de stimulants et s’attarde sur le dépistage des facteurs de risque de mort subite, mais il ne contient pas de recommandations systématiques de dépistage électrocardiographique ou de consultations avec un spécialiste en cardiologie, à moins que les antécédents ou que l’examen physique ne le justifient. Le document contient un questionnaire pour repérer les enfants potentiellement vulnérables à une mort subite (quel que soit le type de TDAH ou les médicaments utilisés pour le traiter). Même si les recommandations dépendent des meilleures données probantes disponibles, le comité s’entend pour affirmer que

  10. N° 341-Diagnostic et prise en charge de la torsion annexielle chez les filles, les adolescentes et les femmes adultes.

    Science.gov (United States)

    Kives, Sari; Gascon, Suzy; Dubuc, Élise; Van Eyk, Nancy

    2017-02-01

    Passer en revue les connaissances scientifiques actuelles et formuler des recommandations relatives au diagnostic et à la prise en charge de la torsion annexielle chez les filles, les adolescentes et les femmes adultes. L'étude porte sur les facteurs de risque, la précision diagnostique, les options de prise en charge et les issues de la torsion annexielle. RéSULTATS: Nous avons examiné les études publiées en faisant des recherches dans MEDLINE, Embase, CINAHL et la Bibliothèque Cochrane à l'aide d'une terminologie contrôlée et de mots-clés appropriés (« adnexal torsion », « ovarian torsion »). Nous avons limité les résultats aux revues systématiques, aux essais contrôlés aléatoires, aux essais cliniques contrôlés et aux études d'observation. Nous avons refait les recherches de façon régulière et intégré de nouvelles données à la directive jusqu'en décembre 2014. Nous avons également étudié la littérature grise (non publiée) trouvée sur les sites Web d'organismes d'évaluation des technologies de la santé et d'autres organismes connexes, dans des collections de directives cliniques et dans des registres d'essais cliniques, et obtenue auprès d'associations nationales et internationales de médecins spécialistes. Les résultats ont été examinés et évalués par le comité CANPAGO de la Société des obstétriciens et gynécologues du Canada (SOGC), sous la direction des auteures principales. Les recommandations ont été classées selon les critères établis par le Groupe d'étude canadien sur les soins de santé préventifs. AVANTAGES, DéSAVANTAGES ET COûTS: L'application de la directive devrait aider les praticiens à adopter une approche de diagnostic et de prise en charge optimale en matière de torsion annexielle, à réduire au minimum les effets néfastes et à améliorer l'issue qui attend les patientes. La présente directive a été évaluée et approuvée par le Comité de pratique - gynécologie de la SOGC

  11. Triglycéridémie postprandiale, insulinémie, leptinémie et distribution des apolipoprotéines CIII entre TGRL et HDL chez l’homme normolipidémique

    Directory of Open Access Journals (Sweden)

    Le Roy Brigitte

    2002-07-01

    Full Text Available Notre article, publié en 1998 dans OCL sur la « Leptine, épuration et utilisation postprandiales des lipides chez l’homme », faisait état pour la première fois d’un lien entre cette hormone produite par le tissu adipeux et le risque de maladies cardiovasculaires lié à un défaut d’épuration des lipides en période postprandiale.

  12. The role of advocacy coalitions in a project implementation process: the example of the planning phase of the At Home/Chez Soi project dealing with homelessness in Montreal.

    Science.gov (United States)

    Fleury, Marie-Josée; Grenier, Guy; Vallée, Catherine; Hurtubise, Roch; Lévesque, Paul-André

    2014-08-01

    This study analyzed the planning process (summer 2008 to fall 2009) of a Montreal project that offers housing and community follow-up to homeless people with mental disorders, with or without substance abuse disorders. With the help of the Advocacy Coalition Framework (ACF), advocacy groups that were able to navigate a complex intervention implementation process were identified. In all, 25 people involved in the Montreal At Home/Chez Soi project were surveyed through interviews (n=18) and a discussion group (n=7). Participant observations and documentation (minutes and correspondence) were also used for the analysis. The start-up phase of the At Home/Chez may be broken down into three separate periods qualified respectively as "honeymoon;" "clash of cultures;" and "acceptance & commitment". In each of the planning phases of the At Home/Chez Soi project in Montreal, at least two advocacy coalitions were in confrontation about their specific belief systems concerning solutions to address the recurring homelessness social problem, while a third, more moderate one contributed in rallying most key actors under specified secondary aspects. The study confirms the importance of policy brokers in achieving compromises acceptable to all advocacy coalitions. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Présence de trois espèces de grégarines (Apicomplexa : Eugregarinorida chez l’Annélide Polychete Marphysa sanguinea (Montagu, 1815 dans le lac de Tunis

    Directory of Open Access Journals (Sweden)

    Elbarhoumi M.

    2010-03-01

    Full Text Available Trois espèces de grégarines ont été trouvées dans des spécimens de l’annélide polychète Marphysa sanguinea récoltés dans le lac de Tunis : Bhatiella marphysae Setna, 1931, parasite de Marphysa sanguinea (Inde, Europe; Ferraria cornucephala iwamusi H. Hoshide, 1956, parasite de Marphysa iwamusi (Japon ; et Viviera sp. qui présente des similitudes avec Viviera marphysae Schrével, 1963, aussi décrite chez Marphysa sanguinea (France. Ces grégarines sont rapportées pour la première fois chez ce dernier hôte en Tunisie. Bhatiella marphysae et Viviera sp. appartiennent à la famille des Lecudinidae (Aseptatorina. La présence d’un septum proto-deutoméritique est confirmée chez Ferraria cornucephala qui doit être maintenue dans les Polyrhabdinae.

  14. New quaternary alkali metal cadmium selenites, A2Cd(SeO3)2 (A = K, Rb, and Cs) and Li2Cd3(SeO3)4

    Science.gov (United States)

    Lü, Minfeng; Jo, Hongil; Oh, Seung-Jin; Ok, Kang Min

    2017-12-01

    A series of new alkali metal cadmium selenites, A2Cd(SeO3)2 (A = K, Rb, and Cs) and Li2Cd3(SeO3)4 have been synthesized in phase pure forms through hydrothermal and solid-state reactions. Structural analyses using single crystal X-ray diffraction indicate that while A2Cd(SeO3)2 and Li2Cd3(SeO3)4 reveal layered structures consisting of CdO6 and SeO3 polyhedra, their symmetry, bonding modes, and the orientation of lone pairs on Se4+ cations are different. A closer examination suggests that the observed structural variations found in the reported materials are attributed to the structure-directing effect of alkali metal cations with different sizes. Scanning electron microscopy/energy dispersive analysis by X-ray, thermogravimetric analysis, Infrared and UV-vis diffuse reflectance spectroscopy, transformation reactions under hydrothermal conditions, and local dipole moment calculations for the reported materials are also reported.

  15. Des recommandations probantes pour surveiller l’innocuité des antipsychotiques de deuxième génération chez les enfants et les adolescents

    Science.gov (United States)

    Pringsheim, Tamara; Panagiotopoulos, Constadina; Davidson, Jana; Ho, Josephine

    2012-01-01

    HISTORIQUE : Au Canada, l’utilisation d’antipsychotiques, notamment les antipsychotiques de deuxième génération (ADG), a augmenté de façon considérable depuis cinq ans chez les enfants ayant des troubles de santé mentale. Ces médicaments ont le potentiel de causer de graves complications métaboliques et neurologiques lorsqu’on les utilise de manière chronique. OBJECTIF : Synthétiser les données probantes relatives aux effets secondaires métaboliques et neurologiques précis associés à l’usage d’ADG chez les enfants et fournir des recommandations probantes sur la surveillance de ces effets secondaires. MÉTHODOLOGIE : Les auteurs ont procédé à une analyse systématique des essais cliniques contrôlés des ADG auprès d’enfants. Ils ont fait des recommandations à l’égard de la surveillance de l’innocuité des ADG d’après un modèle de classification fondé sur le système GRADE (système de notation de l’évaluation et de l’élaboration des recommandations). Lorsque les données probantes n’étaient pas suffisantes, ils fondaient leurs recommandations sur le consensus et l’avis d’experts. Un groupe consensuel multidisciplinaire a analysé toutes les données probantes pertinentes et est parvenu à un consensus à l’égard des recommandations. RÉSULTATS : Les recommandations probantes portant sur la surveillance de l’innocuité des ADG figurent dans les présentes lignes directrices. Les auteurs indiquent la qualité des recommandations relatives à des examens physiques et tests de laboratoire précis à l’égard de chaque ADG à des moments déterminés. CONCLUSION : De multiples essais aléatoires et contrôlés ont permis d’évaluer l’efficacité de bon nombre des ADG utilisés pour traiter les troubles de santé mentale en pédiatrie. Toutefois, leurs avantages ne sont pas sans risques : on observe à la fois des effets secondaires métaboliques et neurologiques chez les enfants traités au moyen d

  16. Télémonitorage des grandes fonctions physiologiques chez les primates vigiles Remote monitoring of physiologic functions in monkeys

    Directory of Open Access Journals (Sweden)

    Guy Germain

    2011-02-01

    Full Text Available Les caractéristiques communes à l'étude des primates non-humains sont proches des contraintes que l'on rencontre dans l'application des principes de la télémédecine humaine. Elles découlent de l’éloignement des animaux et de leur dispersion géographique pour les études en milieu naturel, elles découlent aussi du besoin de contrôler au laboratoire les traitements expérimentaux en perturbant le moins possible le comportement social des animaux. Les ondes radio sont un excellent signal de transmission pour le suivi des animaux parce qu'elles peuvent propager des informations rapidement et sur de longues distances dans l'air. Tous les dispositifs télémétriques consistent en un ou plusieurs capteurs couplés à un émetteur encodeur radio et d'un système d'antenne couplé à un récepteur décodeur, analogique ou numérique. Le progrès des télétransmissions résulte par ailleurs de la miniaturisation des dispositifs électroniques d'acquisition et d'émission qui sont de moins en moins gourmands en énergie et acquièrent des durées d'autonomie beaucoup plus grande. De nombreux dispositifs télémétriques très souvent totalement implantables dans le corps de l'animal sont aujourd'hui commercialement disponibles. Ils permettent une surveillance détaillée des paramètres physiologiques des systèmes cardiovasculaire, nerveux, locomoteur, métabolique, respiratoire et reproducteur chez les primates non-humains entièrement libres de leurs mouvements. Ils sont très largement exploités dans les études pharmacologiques et toxicologiques. D'autres dispositifs encore au stade expérimental intègrent également la combinaison de l'enregistrement télémétrique des pressions, biopotentiels musculaires ou nerveux, température, avec des enregistrements audio et vidéo pouvant être eux-mêmes acquis et transmis, partiellement ou en totalité, par télémétrie. Le développement des systèmes futurs sera probablement axé sur les

  17. Respiratory Syncytial Virus Fusion Protein-Induced Toll-Like Receptor 4 (TLR4) Signaling Is Inhibited by the TLR4 Antagonists Rhodobacter sphaeroides Lipopolysaccharide and Eritoran (E5564) and Requires Direct Interaction with MD-2

    Science.gov (United States)

    Rallabhandi, Prasad; Phillips, Rachel L.; Boukhvalova, Marina S.; Pletneva, Lioubov M.; Shirey, Kari Ann; Gioannini, Theresa L.; Weiss, Jerrold P.; Chow, Jesse C.; Hawkins, Lynn D.; Vogel, Stefanie N.; Blanco, Jorge C. G.

    2012-01-01

    ABSTRACT Respiratory syncytial virus (RSV) is a leading cause of infant mortality worldwide. Toll-like receptor 4 (TLR4), a signaling receptor for structurally diverse microbe-associated molecular patterns, is activated by the RSV fusion (F) protein and by bacterial lipopolysaccharide (LPS) in a CD14-dependent manner. TLR4 signaling by LPS also requires the presence of an additional protein, MD-2. Thus, it is possible that F protein-mediated TLR4 activation relies on MD-2 as well, although this hypothesis has not been formally tested. LPS-free RSV F protein was found to activate NF-κB in HEK293T transfectants that express wild-type (WT) TLR4 and CD14, but only when MD-2 was coexpressed. These findings were confirmed by measuring F-protein-induced interleukin 1β (IL-1β) mRNA in WT versus MD-2−/− macrophages, where MD-2−/− macrophages failed to show IL-1β expression upon F-protein treatment, in contrast to the WT. Both Rhodobacter sphaeroides LPS and synthetic E5564 (eritoran), LPS antagonists that inhibit TLR4 signaling by binding a hydrophobic pocket in MD-2, significantly reduced RSV F-protein-mediated TLR4 activity in HEK293T-TLR4–CD14–MD-2 transfectants in a dose-dependent manner, while TLR4-independent NF-κB activation by tumor necrosis factor alpha (TNF-α) was unaffected. In vitro coimmunoprecipitation studies confirmed a physical interaction between native RSV F protein and MD-2. Further, we demonstrated that the N-terminal domain of the F1 segment of RSV F protein interacts with MD-2. These data provide new insights into the importance of MD-2 in RSV F-protein-mediated TLR4 activation. Thus, targeting the interaction between MD-2 and RSV F protein may potentially lead to novel therapeutic approaches to help control RSV-induced inflammation and pathology. PMID:22872782

  18. The crystal structures of the tri-functional Chloroflexus aurantiacus and bi-functional Rhodobacter sphaeroides malyl-CoA lyases and comparison with CitE-like superfamily enzymes and malate synthases.

    Science.gov (United States)

    Zarzycki, Jan; Kerfeld, Cheryl A

    2013-11-09

    Malyl-CoA lyase (MCL) is a promiscuous carbon-carbon bond lyase that catalyzes the reversible cleavage of structurally related Coenzyme A (CoA) thioesters. This enzyme plays a crucial, multifunctional role in the 3-hydroxypropionate bi-cycle for autotrophic CO2 fixation in Chloroflexus aurantiacus. A second, phylogenetically distinct MCL from Rhodobacter sphaeroides is involved in the ethylmalonyl-CoA pathway for acetate assimilation. Both MCLs belong to the large superfamily of CitE-like enzymes, which includes the name-giving β-subunit of citrate lyase (CitE), malyl-CoA thioesterases and other enzymes of unknown physiological function. The CitE-like enzyme superfamily also bears sequence and structural resemblance to the malate synthases. All of these different enzymes share highly conserved catalytic residues, although they catalyze distinctly different reactions: C-C bond formation and cleavage, thioester hydrolysis, or both (the malate synthases). Here we report the first crystal structures of MCLs from two different phylogenetic subgroups in apo- and substrate-bound forms. Both the C. aurantiacus and the R. sphaeroides MCL contain elaborations on the canonical β8/α8 TIM barrel fold and form hexameric assemblies. Upon ligand binding, changes in the C-terminal domains of the MCLs result in closing of the active site, with the C-terminal domain of one monomer forming a lid over and contributing side chains to the active site of the adjacent monomer. The distinctive features of the two MCL subgroups were compared to known structures of other CitE-like superfamily enzymes and to malate synthases, providing insight into the structural subtleties that underlie the functional versatility of these enzymes. Although the C. aurantiacus and the R. sphaeroides MCLs have divergent primary structures (~37% identical), their tertiary and quaternary structures are very similar. It can be assumed that the C-C bond formation catalyzed by the MCLs occurs as proposed for

  19. Role of the PufX protein in photosynthetic growth of Rhodobacter sphaeroides. 2. PufX is required for efficient ubiquinone/ubiquinol exchange between the reaction center QB site and the cytochrome bc1 complex.

    Science.gov (United States)

    Barz, W P; Verméglio, A; Francia, F; Venturoli, G; Melandri, B A; Oesterhelt, D

    1995-11-21

    The PufX membrane protein is essential for photosynthetic growth of Rhodobacter sphaeroides because it is required for multiple-turnover electron transfer under anaerobic conditions [see accompanying article; Barz, W. P., Francia, F., Venturoli, G., Melandri, B. A., Verméglio, A., & Oesterhelt, D. (1995) Biochemistry 34, 15235-15247]. In order to understand the molecular role of PufX, light-induced absorption spectroscopy was performed using a pufX- mutant, a pufX+ strain, and two suppressor mutants. We show that the reaction center (RC) requires PufX for its functionality under different redox conditions than the cytochrome bc1 complex: When the kinetics of flash-induced reduction of cytochrome b561 were monitored in chromatophores, we observed a requirement of PufX for turnover of the cytochrome bc1 complex only at high redox potential (Eh > 140 mV), suggesting a function of PufX in lateral ubiquinol transfer from the RC. In contrast, PufX is required for multiple turnover of the RC only under reducing conditions: When the Q pool was partially oxidized in vivo using oxygen or electron acceptors like dimethyl sulfoxide or trimethylamine N-oxide, the deletion of PufX had no effect on light-driven electron flow through the RC. Flash train experiments under anaerobic in vivo conditions revealed that RC photochemistry does not depend on PufX for the first two flash excitations. Following the third and subsequent flashes, however, efficient charge separation requires PufX, indicating an important role of PufX for fast Q/QH2 exchange at the QB site of the RC. We show that the Q/QH2 exchange rate is reduced approximately 500-fold by the deletion of PufX when the Q pool is nearly completely reduced, demonstrating an essential role of PufX for the access of ubiquinone to the QB site. The fast ubiquinone/ubiquinol exchange is partially restored by suppressor mutations altering the macromolecular antenna structure. These results suggest an indirect role of PufX in

  20. The unusually strong hydrogen bond between the carbonyl of Q(A) and His M219 in the Rhodobacter sphaeroides reaction center is not essential for efficient electron transfer from Q(A)(-) to Q(B).

    Science.gov (United States)

    Breton, Jacques; Lavergne, Jérôme; Wakeham, Marion C; Nabedryk, Eliane; Jones, Michael R

    2007-06-05

    In native reaction centers (RCs) from photosynthetic purple bacteria the primary quinone (QA) and the secondary quinone (QB) are interconnected via a specific His-Fe-His bridge. In Rhodobacter sphaeroides RCs the C4=O carbonyl of QA forms a very strong hydrogen bond with the protonated Npi of His M219, and the Ntau of this residue is in turn coordinated to the non-heme iron atom. The second carbonyl of QA is engaged in a much weaker hydrogen bond with the backbone N-H of Ala M260. In previous work, a Trp side chain was introduced by site-directed mutagenesis at the M260 position in the RC of Rb. sphaeroides, resulting in a complex that is completely devoid of QA and therefore nonfunctional. A photochemically competent derivative of the AM260W mutant was isolated that contains a Cys side chain at the M260 position (denoted AM260(W-->C)). In the present work, the interactions between the carbonyl groups of QA and the protein in the AM260(W-->C) suppressor mutant have been characterized by light-induced FTIR difference spectroscopy of the photoreduction of QA. The QA-/QA difference spectrum demonstrates that the strong interaction between the C4=O carbonyl of QA and His M219 is lost in the mutant, and the coupled CO and CC modes of the QA- semiquinone are also strongly perturbed. In parallel, a band assigned to the perturbation of the C5-Ntau mode of His M219 upon QA- formation in the native RC is lacking in the spectrum of the mutant. Furthermore, a positive band between 2900 and 2400 cm-1 that is related to protons fluctuating within a network of highly polarizable hydrogen bonds in the native RC is reduced in amplitude in the mutant. On the other hand, the QB-/QB FTIR difference spectrum is essentially the same as for the native RC. The kinetics of electron transfer from QA- to QB were measured by the flash-induced absorption changes at 780 nm. Compared to native RCs the absorption transients are slowed by a factor of about 2 for both the slow phase (in the

  1. Plasmon waveguide resonance spectroscopic evidence for differential binding of oxidized and reduced rhodobacter capsulatus cytochrome c(2) to the cytochrome bc(1) complex mediated by the conformation of the rieske iron-sulfur protein

    International Nuclear Information System (INIS)

    Devanathan, S.; Salamon, Z.; Tollin, G.; Fitch, J.C.; Meyer, T.E.; Berry, E.A.; Cusanovich, M.A.

    2007-01-01

    The dissociation constants for the binding of Rhodobacter capsulatus cytochrome c2 and its K93P mutant to the cytochrome bc1 complex embedded in a phospholipid bilayer were measured by plasmon waveguide resonance spectroscopy in the presence and absence of the inhibitor stigmatellin. The reduced form of cytochrome c2 strongly binds to reduced cytochrome bc1 (Kd = 0.02 M) but binds much more weakly to the oxidized form (Kd = 3.1 M). In contrast, oxidized cytochrome c2 binds to oxidized cytochrome bc1 in a biphasic fashion with Kd values of 0.11 and 0.58 M. Such a biphasic interaction is consistent with binding to two separate sites or conformations of oxidized cytochrome c2 and/or cytochrome bc1. However, in the presence of stigmatellin, we find that oxidized cytochrome c2 binds to oxidized cytochrome bc1 in a monophasic fashion with high affinity (Kd = 0.06 M) and reduced cytochrome c2 binds less strongly (Kd = 0.11 M) but ∼30-fold more tightly than in the absence of stigmatellin. Structural studies with cytochrome bc1, with and without the inhibitor stigmatellin, have led to the proposal that the Rieske protein is mobile, moving between the cytochrome b and cytochrome c1 components during turnover. In one conformation, the Rieske protein binds near the heme of cytochrome c1, while the cytochrome c2 binding site is also near the cytochrome c1 heme but on the opposite side from the Rieske site, where cytochrome c2 cannot directly interact with Rieske. However, the inhibitor, stigmatellin, freezes the Rieske protein iron-sulfur cluster in a conformation proximal to cytochrome b and distal to cytochrome c1. We conclude from this that the dual conformation of the Rieske protein is primarily responsible for biphasic binding of oxidized cytochrome c2 to cytochrome c1. This optimizes turnover by maximizing binding of the substrate, oxidized cytochrome c2, when the iron-sulfur cluster is proximal to cytochrome b and minimizing binding of the product, reduced cytochrome c

  2. Les infections urinaires chez les patients insuffisants rénaux chroniques hospitalisés au service de néphrologie: profil bactériologique et facteurs de risque

    Science.gov (United States)

    Chemlal, Abdeljalil; Ismaili, Fatiha Alaoui; Karimi, Ilham; Elharraqui, Ryme; Benabdellah, Nawal; Bekaoui, Samira; Haddiya, Intissar; Bentata, Yassamine

    2015-01-01

    L'infection urinaire chez l'insuffisant rénal est fréquente et particulière dans sa prise en charge diagnostique et thérapeutique. L'objectif de notre étude est de déterminer le profil bactériologique et d’étudier les facteurs de risque des infections urinaires chez le patient insuffisant rénal chronique en milieu de néphrologie. Etude prospective débutée en Septembre 2012 menée au service de néphrologie à l'hôpital régional d'Oujda de l'oriental Marocain. Ont été inclus tous les patients hospitalisés en néphrologie avec une infection urinaire documentée. Nous avons analysé les données démographiques, cliniques, biologiques, et thérapeutiques de nos patients à l'admission et au cours de leurs hospitalisations. 48 épisodes d'infections urinaires chez 43 patients ont été colligés dont 3 enfants. L'incidence de l'infection urinaire dans notre étude était de 4,65%. La médiane d’âge était de 53 (32-66) années. 60,4% étaient de sexe féminin. Le germe isolé était un Escheria Coli dans 58,3% et un Klebsiella dans 29,2%. Le germe isolé était résistant à l'amoxicilline-acide clavulanique dans 83% des cas. L'antibiotique prescris en premiére intention chez nos patients était une céphalosporine de 3 éme génération dans 50%. L’évolution chez nos patients était favorable dans 89,6% des cas. 33,3% avaient présenté un sepsis et on a noté le décès dans 10,4% des cas. Les infections urinaires chez l'insuffisant rénal chronique reste très grave vu leur lourde morbi-mortalié d'où l'intêrét d'un dépistage précoce chez cette population. Un usage raisonné des antibiotiques est nécessaire afin de prévenir l'extension des résistances bactériennes. PMID:26213601

  3. Infection par le VIH chez les patientes atteintes de cancer du sein en Guinée (Afrique de l'Ouest)

    Science.gov (United States)

    Traore, Bangaly; Diane, Solomana; Sow, Mamadou Saliou; Keita, Mamady; Conde, Mamoudou; Traore, Fodé Amara; Kourouma, Tidiane

    2015-01-01

    L'objectif était de déterminer la prévalence de l'infection à VIH chez les patientes atteintes de cancer du sein et de comparer les caractéristiques anatomocliques et thérapeutiques de ces cancers du sein par rapports aux patientes non infectées par le VIH. Il s'agissait d'une étude rétrospective et analytique comparant les dossiers de patientes atteintes de cancers du sein histologiquement confirmés, infectées ou non par le VIH à l'unité de chirurgie oncologique de Donka, CHU de Conakry, de 2007 à 2012. Nous avons colligé 278 patientes présentant un cancer du sein dont 14 (5,0%) infectées par le VIH et 264 (95,0%) non infectées par le VIH. Les différences observées entre ces deux groupes de patientes étaient respectivement: âge médian (36,8 vs 49,0 ans), la ménopause (21,4% vs 53,4%), le nombre des patientes traitées (50,0% contre 77,1%) et la survenue de décès (78,6% vs 50,8%). Aucune différence n'a été notée dans la présentation clinique, histologique et le retard de consultation. Dans notre étude, la prévalence de l'infection à VIH chez les patients atteints de cancer du sein est élevée. L’âge jeune des patients, la faible accessibilité au traitement et la mortalité élevée doivent être confirmés par une étude sur un échantillon plus large. PMID:26523196

  4. Evolution post-opératoire des séquelles de tuberculose pulmonaire chez les séropositifs VIH

    Science.gov (United States)

    Grégoire, Ayegnon Kouakou; Flavien, Kendja Hypolite; Raphaël, Ouédé; Démine, Blaise; Christophe, Ménéas Gueu; Marie, Ano Kounangui; Hervé, Yangni-Angaté Koffi; Yves, Tanauh

    2014-01-01

    Cette étude rapporte les aspects cliniques et évolutifs des séquelles pulmonaires tuberculeuses (SPT) opérées chez les séropositifs (VIH+). Il s'agit d'une étude prospective transversale réalisée entre Novembre 2005 et Octobre 2012. Elle a porté sur 20 patients VIH+, ayant dans leurs antécédents, une tuberculose pulmonaire (TP) traitée et déclarée guérie, et admise dans ladite période pour une chirurgie de la SPT secondaire. Une enquête sérologique VIH a été réalisée systématiquement au cours du bilan pré-opératoire. Le diagnostic pré-opératoire de la SPT, la mortalité, les complications post- opératoires (CPOP), le séjour hospitalier, le suivi à moyen terme des STP opérées ont été évalués. Les séropositifs étaient VIH1+ (n = 12; 60%), VIH1&2+ (n = 4; 20%) et VIH2+ (n = 4; 20%). La durée moyenne d’évolution des STP était de 26,22 ± 21,3 mois. Les STP étaient les pyothorax ou pleurésies enkystées (n = 16; 80%), le poumon détruit (n = 2;10%) et les dilatations de bronches (n = 2;10%). Les VIH+ ne présentaient pas d'aspergillome pulmonaire. Le séjour hospitalier moyen était 13,1 ± 10,2 jours. Le suivi total était de 82 patients-année avec une moyenne de suivi de 4,2 ± 2,3 ans (extrêmes: 1 et 7 ans). Le taux de mortalité à court et moyen terme était nul. Aucun décès post-opératoire immédiat n'a été noté. Les CPOP immédiates étaient les bullages prolongés chez 75% des immunodéprimés. Les CPOP tardives (n = 3) étaient un syndrome restrictif pulmonaire, un pyothorax persistant et une pachypleurite résiduelle restrictive. A court terme, le taux de guérison radiologique était de 80% (n = 16). PMID:24932331

  5. Anoplastie périnéale simple pour le traitement des malformations anorectales basses chez l'adulte, à propos de deux cas

    Science.gov (United States)

    Echchaoui, Abdelmoughit; Benyachou, Malika; Hafidi, Jawad; Fathi, Nahed; Mohammadine, Elhamid; ELmazouz, Samir; Gharib, Nour-eddine; Abbassi, Abdellah

    2014-01-01

    Les malformations anorectales chez l'adulte sont des anomalies congénitales rares du tube digestif qui prédominent chez le sexe féminin. Notre étude porte sur deux observations de malformation anorectale basses vues et traitées au stade adulte par les 2 équipes (plasticiens et viscéralistes) à l'Hôpital Avicenne à Rabat. Il s'agit d'un homme de 24 ans avec une dyschésie anale l'autre cas est une femme de 18 ans avec une malformation anovulvaire Les caractéristiques cliniques combinées avec les imageries radiologiques (lavement baryté, et la manométrie anorectale) ont confirmé qu'il s'agit d'une malfomation anorectale basse. Les deux cas sont corrigés par une reconstruction sphinctérienne, réimplantation anale avec anoplastie périnéale. Les suites opératoires étaient simples, pas de souffrance cutanée ou nécrose, avec changement de pansement gras chaque jour. Le résultat fonctionnel (la continence) était favorable pour les 2 patients. La présentation des MAR à l’âge adulte est rare, d’étiologie mal connu, elles apparaissent selon le mode sporadique. Les caractéristiques cliniques, couplées à l'imagerie (lavement baryté, IRM pelvienne), l'endoscopie et la manométrie anorectale, permettent de confirmer le diagnostic et classer ces anomalies en 3 types: basses, intermédiaires, et hautes. Les formes basses sont traités d'emblée par une réimplantation anale et anoplastie périnéale simple tels nos deux cas, elles peuvent être traités dans certains cas par un abaissement anorectale associé à une plastie V-Y permettant ainsi un emplacement anatomique correct de l'anus; alors que les formes hautes ou intermédiaires relèvent d'une chirurgie complexe avec souvent une dérivation digestive transitoire. Contrairement aux autres formes, Les formes basses ont un pronostic fonctionnel favorable. PMID:25667689

  6. SOLUTIONS AUX PROBLEMES DE L'INTERFERENCE LINGUISTIQUE CHEZ L'APPRENANT YORUBA PHONE DE LA LANGUE FRANCAISE AU NIGERIA.E

    Directory of Open Access Journals (Sweden)

    Alaje Oyebola Olubunmi

    2014-06-01

    Full Text Available Le transfert interlingual d'une langue a l'autre qui soit volontaire soit involontaire est un changement de la norme d'une langue. Une langue n'a jamais enseigne a travers un simple contenu linguistique. L'enseignement des langues s'opere toujours dans un contexte de contacts entre plusieurs culturees parce que toute langue vehicule a avec elle une culture dont elle est a la fois productrice et le produit. En principe, l'apprenant nigerian possede des multiples systemes linguistiques dont laquelle la connaissance qu'il a de ces systemes peut etre variable. L'interference de la connaissance anterieure des autres langues pose un grand probleme a l'etude du francais chez les apprenants nigerians. Ce travail est destine a mettre en evidence du point-de-vue de la linguistique, certaines de ces fautes d'une part et a suggerer quelques mesures qui permettront de les resoudre d'autre part afin de contribuer a faire progresser l'enseignement et l'apprentissage du francais au Nigeria. Il est motive par le souci d'identifier et d'exposer les sources des problemes d'interference des apprenants qui apprennent la langue francaise a l'ecole secondaire jusqu'a l'universite ou les raisons pour laquelle les apprenants rencontrent ces problemes de l'interference.

  7. Portage vaginal du streptocoque du groupe B chez la femme enceinte au niveau de la région de Marrakech

    Science.gov (United States)

    Bassir, Ahlam; Dhibou, Hanane; Farah, Majdi; Mohamed, Lharmis; Amal, Addebous; Nabila, Souraa; Abderahim, Aboulfalah; Asmouki, Hamid; Soummani, Abderraouf

    2016-01-01

    Introduction Le streptocoque du groupe B est le principal agent impliqué dans les infections materno-fœtales, les septicémies et les méningites du nouveau-né à terme. L'objectif est de déterminer le taux de portage maternel du streptocoque du groupe B (SGB) à terme. Méthodes Un prélèvement vaginal a été réalisé de manière prospective chez 275 parturientes lors de l'entrée en salle d'accouchement sur une période de 06 mois. Résultats Le taux de portage était de 20,2%. Le portage était variable en fonction de l’âge gestationnel, il constitue 57.5% entre 37 et 38 semaines d'aménorrhée. Aucun des facteurs de risque n'a était statistiquement prédictif du portage maternel du SGB. Conclusion Le dépistage doit être réalisé à partir de 37 semaines d'aménorrhée, et comme le portage est intermittent, un prélèvement négatif ne garantirait pas que le portage soit négatif à l'accouchement. PMID:27222693

  8. Study of the kinetics of strontium elimination in the rat; Etude de la cinetique de l'elimination du strontium chez le rat

    Energy Technology Data Exchange (ETDEWEB)

    Guilloux, M J; Michon, G [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1958-07-01

    A kinetic study of strontium elimination was made on rats after a single oral administration of 3 to 5 {mu}curies of carrier free Sr{sup 90}. The curve showing the body burden in function of time may be considered as the sum of three exponential terms with half-lives of 14 hours, 72 days, 153 days. The term with a half-live of 153 days represents the metabolism of strontium in the bone; it is predominant since the 17. day and its extrapolation to time zero shows that things seem to proceed as if 18 per cent of the administered amount were deposited in the skeleton. (author) [French] La cinetique de l'elimination du strontium chez le rat a ete etudiee apres une administration orale unique de 3 a 5 {mu}curies de {sup 90}Sr repute sans entraineur. La courbe representant la quantite presente dans l'organisme en fonction du temps peut etre assimilee a la somme de trois termes exponentiels de periode 14 heures, 72 jours, 153 jours. Le terme de periode 153 jours represente le metabolisme osseux du strontium, il est preponderant des le 17. jour et son extrapolation au temps zero nous montre qu'en definitive, tout se passe comme si 18 pour cent de la quantite administree etaient deposes dans le squelette. (auteur)

  9. Recovery and radio-resistance in mice after external irradiation; Restauration et radio-resistance chez la souris apres irradiation externe

    Energy Technology Data Exchange (ETDEWEB)

    Le Guillou, S [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1965-07-01

    The author presents a literature study concerning recovery from external irradiation and an analysis of experimental data (which appear to suggest the idea of a radio-resistance in animals), as well as the hypotheses put forward for explaining this phenomenon. The author then describes an experiment carried out on mice whose LD 50/30 days increased from 1005 to 1380 rads and for which it was shown that an increase occurs in the number of certain anti-bodies circulating after a low dose of {gamma} irradiation. (author) [French] L'auteur presente une etude bibliographique de la restauration apres irradiation externe et une analyse des donnees experimentales qui paraissent suggerer la notion de radioresistance chez les animaux ainsi que les hypotheses cherchant a expliquer ce phenomene. Il relate ensuite une experience realisee sur des souris dont la DL 50/30 jours est passee de 1005 a 1380 rads et dans laquelle est montree l'augmentation de certains anticorps circulant apres une faible dose d'irradiation gamma. (auteur)

  10. Housing First for People With Severe Mental Illness Who Are Homeless: A Review of the Research and Findings From the At Home–Chez soi Demonstration Project

    Science.gov (United States)

    Aubry, Tim; Nelson, Geoffrey; Tsemberis, Sam

    2015-01-01

    Objective: To provide a review of the extant research literature on Housing First (HF) for people with severe mental illness (SMI) who are homeless and to describe the findings of the recently completed At Home (AH)–Chez soi (CS) demonstration project. HF represents a paradigm shift in the delivery of community mental health services, whereby people with SMI who are homeless are supported through assertive community treatment or intensive case management to move into regular housing. Method: The AH–CS demonstration project entailed a randomized controlled trial conducted in 5 Canadian cities between 2009 and 2013. Mixed methods were used to examine the implementation of HF programs and participant outcomes, comparing 1158 people receiving HF to 990 people receiving standard care. Results: Initial research conducted in the United States shows HF to be a promising approach, yielding superior outcomes in helping people to rapidly exit homelessness and establish stable housing. Findings from the AH–CS demonstration project reveal that HF can be successfully adapted to different contexts and for different populations without losing its fidelity. People receiving HF achieved superior housing outcomes and showed more rapid improvements in community functioning and quality of life than those receiving treatment as usual. Conclusions: Knowledge translation efforts have been undertaken to disseminate the positive findings and lessons learned from the AH–CS project and to scale up the HF approach across Canada. PMID:26720504

  11. Recovery and radio-resistance in mice after external irradiation; Restauration et radio-resistance chez la souris apres irradiation externe

    Energy Technology Data Exchange (ETDEWEB)

    Le Guillou, S. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1965-07-01

    The author presents a literature study concerning recovery from external irradiation and an analysis of experimental data (which appear to suggest the idea of a radio-resistance in animals), as well as the hypotheses put forward for explaining this phenomenon. The author then describes an experiment carried out on mice whose LD 50/30 days increased from 1005 to 1380 rads and for which it was shown that an increase occurs in the number of certain anti-bodies circulating after a low dose of {gamma} irradiation. (author) [French] L'auteur presente une etude bibliographique de la restauration apres irradiation externe et une analyse des donnees experimentales qui paraissent suggerer la notion de radioresistance chez les animaux ainsi que les hypotheses cherchant a expliquer ce phenomene. Il relate ensuite une experience realisee sur des souris dont la DL 50/30 jours est passee de 1005 a 1380 rads et dans laquelle est montree l'augmentation de certains anticorps circulant apres une faible dose d'irradiation gamma. (auteur)

  12. Du caractère sociable de l’intime : le plaisir esthétique chez Kant, entre solitude et communication

    Directory of Open Access Journals (Sweden)

    Raphaël Ehrsam

    2016-11-01

    Full Text Available Dans une large mesure, du XVIIe au XVIIIe siècle, on assiste à une métamorphose théorique des rapports entre plaisir, solitude et sociabilité. Tandis qu’au XVIIe siècle (et encore chez plusieurs auteurs du XVIIIe, le plaisir est décrit comme une expérience dont le lieu principal est la sociabilité, à l’inverse de la méditation sise de préférence dans la solitude, le XVIIIe siècle réinscrit le plaisir dans l’intimité solitaire du moi et majore l’idée d’une nécessaire communauté des sujets connaissant. La caractérisation kantienne de l’expérience esthétique, comme expérience d’un plaisir qui enveloppe immédiatement une prétention à l’universalité et à la communication, apparaît dès lors comme une façon de rompre la logique de ce chiasme.

  13. Blast pulmonaire primaire chez le brûlé. a propos d’un cas et revue de la littérature

    Science.gov (United States)

    Siah, S.; Emane, A.; Bertin-Maghit, M.

    2016-01-01

    Summary Le blast est à l’origine de lésions spécifiques pour lesquelles une prise en charge spécialisée est nécessaire. Après une explosion on peut observer des lésions de blast primaire, liées à l’onde de choc, secondaire par polycriblage et tertiaire par projection du patient. Les blasts secondaire et tertiaire sont plus fréquents que le blast primaire et peuvent entraîner un polytraumatisme. Dans 5% des cas, on retrouve des brûlures pouvant faire partie du blast quaternaire, qui regroupe toutes les lésions d’autres mécanismes que ceux précités. La prise en charge des lésions secondaires et tertiaires de blast est comparable à celle des traumatisés graves. Le blast pulmonaire primaire aggrave le pronostic des blessés les plus graves mais impose rarement une prise en charge spécifique. La connaissance des particularités physiopathologiques et lésionnelles permet de mieux traiter les blastés et brûlés graves survivants. Nous rapportons une observation de blast pulmonaire primaire chez un brûlé. PMID:28149247

  14. Synthesis, second-harmonic generation (SHG), and photoluminescence (PL) properties of noncentrosymmetric bismuth selenite solid solutions, Bi2-xLnxSeO5 (Ln = La and Eu; x = 0-0.3)

    Science.gov (United States)

    Qi, Hai-Xin; Jo, Hongil; Oh, Seung-Jin; Ok, Kang Min

    2018-02-01

    A series of La3+ or Eu3+-doped noncentrosymmetric (NCS) bismuth selenite solid solutions, Bi2-xLnxSeO5 (x = 0.1, 0.2, and 0.3), have been successfully synthesized via standard solid-state reactions under vacuum with Bi2O3, La2O3 (or Eu2O3), and SeO2 as starting materials. Crystal structures and phase purities of the resultant materials were thoroughly characterized by powder X-ray diffraction using the Rietveld method. The results clearly show that the reported materials crystallize in the orthorhombic space group, Abm2 (No. 39), and exhibit pseudo-three-dimensional frameworks consisting of BiO3, BiO5, and SeO3 polyhedra that share edges and corners. Detailed diffraction studies indicate that the cell volume of Bi2-xLnxSeO5 decreases with an increasing amount of Ln3+ on the Bi3+ sites. However, no ordering between Ln3+ and Bi3+ was observed in the Bi2-xLnxSeO5 solid solutions. Powder second-harmonic generation (SHG) measurements, using 1064 nm radiation, reveal that SHG efficiencies of Bi2-xLnxSeO5 solid solutions continuously decrease as more Ln3+ cations are added to the sites of polarizable Bi3+ cations. Photoluminescence (PL) measurements on Bi2-xEuxSeO5 exhibit three specific emission peaks at 592, 613, and 702 nm (5D0 → 7F1, 2, 4) owing to the 4f-4f intrashell transitions of Eu3+ ions.

  15. Chemical and structural evolution in the Th-SeO3(2-)/SeO4(2-) system: from simple selenites to cluster-based selenate compounds.

    Science.gov (United States)

    Xiao, Bin; Langer, Eike; Dellen, Jakob; Schlenz, Hartmut; Bosbach, Dirk; Suleimanov, Evgeny V; Alekseev, Evgeny V

    2015-03-16

    While extensive success has been gained in the structural chemistry of the U-Se system, the synthesis and characterization of Th-based Se structures are widely unexplored. Here, four new Th-Se compounds, α-Th(SeO3)2, β-Th(SeO3)2, Th(Se2O5)2, and Th3O2(OH)2(SeO4)3, have been obtained from mild hydrothermal or low-temperature (180-220 °C) flux conditions and were subsequently structurally and spectroscopically characterized. The crystal structures of α-Th(SeO3)2 and β-Th(SeO3)2 are based on ThO8 and SeO3 polyhedra, respectively, featuring a three-dimensional (3D) network with selenite anions filling in the Th channels along the a axis. Th(Se2O5)2 is a 3D framework composed of isolated ThO8 polyhedra interconnected by [Se2O5](2-) dimers. Th3O2(OH)2(SeO4)3 is also a 3D framework constructed by octahedral hexathorium clusters [Th6(μ3-O)4(μ3-OH)4](12+), which are interlinked by selenate groups SeO4(2-). The positions of the vibrational modes associated with both Se(IV)O3(2-) and Se(VI)O4(2-) units, respectively, were determined for four compounds, and the Raman spectra of α- and β-Th(SeO3)2 are compared and discussed in detail.

  16. Variable dimensionality and framework found in a series of quaternary zinc selenites, A2Zn3(SeO3)4·xH2O (A = Na, Rb, and Cs; 0≤x≤1) and Cs2Zn2(SeO3)3·2H2O

    International Nuclear Information System (INIS)

    Lü, Minfeng; Jo, Hongil; Oh, Seung-Jin; Ok, Kang Min

    2017-01-01

    Five new alkali metal zinc selenites, A 2 Zn 3 (SeO 3 ) 4 ·xH 2 O (A = Na, Rb, and Cs; 0≤x≤1) and Cs 2 Zn 2 (SeO 3 ) 3 ·2H 2 O have been synthesized by heating a mixture of ZnO, SeO 2 and A 2 CO 3 (A = Na, Rb, and Cs), and characterized by X-ray diffraction (XRD) and spectroscopic analyses techniques. All of the reported materials revealed a rich structural chemistry with different frameworks and connection modes of Zn 2+ . While Rb 2 Zn 3 (SeO 3 ) 4 and Cs 2 Zn 3 (SeO 3 ) 4 ·H 2 O revealed three-dimensional frameworks consisting of isolated ZnO 4 tetrahedra and SeO 3 polyhedra, Na 2 Zn 3 (SeO 3 ) 4 , Cs 2 Zn 3 (SeO 3 ) 4 , and Cs 2 Zn 2 (SeO 3 ) 3 ·2H 2 O contained two-dimensional [Zn 3 (SeO 3 ) 4 ] 2- layers. Specifically, whereas isolated ZnO 4 tetrahedra and SeO 3 polyhedra are arranged into two-dimensional [Zn 3 (SeO 3 ) 4 ] 2- layers in two cesium compounds, circular [Zn 3 O 10 ] 14- chains and SeO 3 linkers are formed in two-dimensional [Zn 3 (SeO 3 ) 4 ] 2- layers in Na 2 Zn 3 (SeO 3 ) 4 . Close structural examinations suggest that the size of alkali metal is significant in determining the framework geometry as well as connection modes of transition metal cations. - Graphical abstract: Variable dimensions and frameworks were found in a series of quaternary zinc selenites, A 2 Zn 3 (SeO 3 ) 4 (A = Na, Rb and Cs). - Highlights: • Five novel quaternary zinc selenites are synthesized. • All the selenites with different structures contain polarizable d 10 and lone pair cations. • The size of alkali metal cations is significant in determining the framework geometry.

  17. Clinical and symptomatological study of pigs subjected to a lethal dose of integral gamma irradiation; Etude clinique et symptomatologique chez le porc soumis a une irradiation gamma totale a dose letale

    Energy Technology Data Exchange (ETDEWEB)

    Vaiman, M; Guenet, J -L; Maas, J; Nizza, P

    1966-05-01

    Results are reported from a clinical and haematological study on a Corsican species of pigs wholly exposed to an approximately lethal dose of {gamma} radiation. The aim of this work was to examine the changes in the irradiation syndrome of irradiation for pigs to make it thus possible to devise further experiments, in particular in the therapeutic field. The dose received was 285 rads (measured as the absorption in the vertical antero-posterior medial plane). Data are presented on cyto-haematological changes in the blood circulating immediately after irradiation, and followed up to death, and changes in the medullary cytology after irradiation. The clinical picture of lethal radiation injury in swine is described. (authors) [French] Les auteurs rapportent les resultats d'une etude clinique et hematologique chez des porcs de race corse irradies in toto a dose sensiblement letale. Le but de cette etude etait de connaitre l'evolution du syndrome aigu d'irradiation chez le porc et de permettre ainsi le developpement d'experimentations ulterieures, en particulier dans le domaine therapeutique. La dose delivree etait de 285 rad (en dose absorbee au niveau du plan median vertical anteroposterieur. L'etude a porte essentiellement: 1. Sur les modifications cyclo-hematologiques du sang circulant immediatement apres l'irradiation, pour les differentes lignees cellulaires; l'evolution de ces modifications a ete notee jusqu'a la mort; 2. Sur les modifications de la cytologie medullaire apres irradiation (evolution du myelogramme et essai d'evaluation de la cellularite de la moelle osseuse);: 3. Sur les signes cliniques, d'ailleurs tres discrets, observes chez les porcs apres irradiation. (auteurs)

  18. Clinical and symptomatological study of pigs subjected to a lethal dose of integral gamma irradiation; Etude clinique et symptomatologique chez le porc soumis a une irradiation gamma totale a dose letale

    Energy Technology Data Exchange (ETDEWEB)

    Vaiman, M.; Guenet, J.-L.; Maas, J.; Nizza, P

    1966-05-01

    Results are reported from a clinical and haematological study on a Corsican species of pigs wholly exposed to an approximately lethal dose of {gamma} radiation. The aim of this work was to examine the changes in the irradiation syndrome of irradiation for pigs to make it thus possible to devise further experiments, in particular in the therapeutic field. The dose received was 285 rads (measured as the absorption in the vertical antero-posterior medial plane). Data are presented on cyto-haematological changes in the blood circulating immediately after irradiation, and followed up to death, and changes in the medullary cytology after irradiation. The clinical picture of lethal radiation injury in swine is described. (authors) [French] Les auteurs rapportent les resultats d'une etude clinique et hematologique chez des porcs de race corse irradies in toto a dose sensiblement letale. Le but de cette etude etait de connaitre l'evolution du syndrome aigu d'irradiation chez le porc et de permettre ainsi le developpement d'experimentations ulterieures, en particulier dans le domaine therapeutique. La dose delivree etait de 285 rad (en dose absorbee au niveau du plan median vertical anteroposterieur. L'etude a porte essentiellement: 1. Sur les modifications cyclo-hematologiques du sang circulant immediatement apres l'irradiation, pour les differentes lignees cellulaires; l'evolution de ces modifications a ete notee jusqu'a la mort; 2. Sur les modifications de la cytologie medullaire apres irradiation (evolution du myelogramme et essai d'evaluation de la cellularite de la moelle osseuse);: 3. Sur les signes cliniques, d'ailleurs tres discrets, observes chez les porcs apres irradiation. (auteurs)

  19. Etude du strabisme chez des enfants de 0 à 15 ans suivis a Lubumbashi, République Démocratique du Congo: analyse des aspects épidémiologiques et cliniques

    Science.gov (United States)

    Bienvenu, Yogolelo Asani; Angel, Musau Nkola; Sebastien, Mbuyi Musanzayi; Philippe, Cilundika Mulenga; Léon, Kabamba Ngombe; Eugene, Twite Kabange; Chami, Cham Lubamba; Prosper, Kalenga Muenze Kayamba; Claude, Speeg-Schatz; Gaby, Chenge Borasisi

    2015-01-01

    Introduction Le strabisme est défini comme un syndrome à double composante: motrice et sensorielle. Le but de ce travail est de décrire les aspects épidémiologiques et cliniques du strabisme chez l'enfant congolais de 0 à 15 ans dans la ville de Lubumbashi. Méthodes Il s'agit d'une étude descriptive longitudinale sur les aspects épidémiologiques et cliniques du strabisme chez l'enfant congolais de 0 à 15 ans dans la ville de Lubumbashi entre Décembre 2012 à Décembre 2013. Nous avons recueilli l’âge des patients, leur sexe, leur provenance, le type de strabisme, la réfraction, le fond d'oeil, les antécédents (hérédité) ainsi que le type de la déviation strabique observé sur 70 patients. Résultats Nous avons observé 70 cas de strabisme manifeste dont 31 cas (44,28%) étaient dans la tranche d’âge comprise entre 0 et 5 ans. L’âge moyen de nos patients était de 6,7 ans avec une prédominance du sexe féminin, soit 51,42%. Le strabisme était convergent dans 65,71%, divergent dans 30%, et vertical dans 4,28%. Les ésotropies représentaient 65 cas (92,85%), quatre cas (5,71%) avaient un antécédent familial de strabisme au premier degré de parenté, 21 cas (30%) au second degré de parenté, 45 cas (64,28%) n'avaient pas cet antécédent. L'oeil gauche était le plus dominé dans 30% des cas. Les facteurs favorisant le strabisme étaient inconnus dans 54 cas (77,14%). Le strabisme était secondaire à l'hypermétropie chez 32 patients (42,71%). Conclusion La fréquence du strabisme dans la ville de Lubumbashi chez les enfants âgés de 0 à 15 ans est de 0,50%. Comme dans la plupart des études sur le strabisme de l'enfant, c'est l’ésotropie qui est la déviation la plus commune. PMID:26834919

  20. Identification d’une nouvelle molécule d’intérêt chez le cheval atteint d’obstruction récurrente des voies respiratoires: La Pentraxine 3

    OpenAIRE

    Ramery, Eve

    2010-01-01

    L’ORVR ou obstruction récurrente des voies respiratoires (ORVR) est la cause la plus fréquente de maladie pulmonaire chronique chez le cheval adulte. La maladie se caractérise par une hyperréactivité bronchique, une production excessive de mucus et une inflammation neutrophilique pulmonaire qui ont pour effet de réduire la compliance dynamique du poumon et d’augmenter la résistance des voies respiratoires au débit aérien. Alors que la maladie est une entité documentée dans la littérature depu...

  1. Note de synthèse sur la sélection de niche spatiale et la compétition chez le jeune saumon Atlantique (Salmo salar et la truite commune (Salmo trutta en milieu lotique

    Directory of Open Access Journals (Sweden)

    HEGGENES J.

    1995-04-01

    Full Text Available La sélection de l'habitat analysée à partir d'un ensemble de données récoltées sur des cours d'eau hétérogènes du point de vue spatio-temporel doit être interprétée en fonction du site et de l'échelle d'étude. La microniche spatiale fondamentale du juvénile de saumon Atlantique et de truite commune est caractérisée en été par une forte préférence pour une faible valeur de la vitesse de courant focale en raison d'une stratégie de gain énergétique basée essentiellement sur une prise alimentaire de la faune dérivante qui permet de maximiser les comportements de prise de position et d'attente du poisson. Cette microniche est également dépendante de la taille : chez le saumon, les plus gros parrs sont tolérants ; par contre chez la truite, une préférence accrue pour les habitats profonds est observée lorsqu'elles grossissent. La niche effective de la truite est relativement plus structurée par des valeurs élevées de la profondeur d'eau et des valeurs faibles de vitesse de courant lorsqu'elle est comparée à celle du saumon caractérisée par de faibles hauteurs d'eau et par des vitesses de courant élevées. Ces différences proviennent d'une plus grande tolérance du saumon pour les fortes vitesses de courant, combinée à un déplacement de la niche de cette espèce par suite d'une compétition avec la truite qui est plus agressive. Cette compétition interactive et interspécifique aboutit à une réduction de la niche spatiale effective chez le Saumon lorsque les paramètres vitesse de courant et profondeur d'eau sont pris en compte simultanément, et pas chez la truite.

  2. Bioaccumulation of selenium and induced biological effects in the filter feeding bivalve Corbicula fluminea: influence of ventilatory activity, selenium speciation and route of transfer; Bioaccumulation du selenium et effets biologiques induits chez le bivalve filtreur Corbicula fluminea: prise en compte de l'activite ventilatoire, de la speciation du selenium et de la voie de contamination

    Energy Technology Data Exchange (ETDEWEB)

    Fournier, E

    2005-10-15

    Selenium is an essential micro-nutrient for most of living organisms. However, toxic effects in several ecosystems have been reported in the literature. Toxicity comprehension is difficult due to the complexity of Se oxidation states in the environment. The aim of this thesis work was to acquire knowledge on the physiological and environmental factors involved in bioaccumulation and toxicity processes in the freshwater filter-feeding bivalve C. fluminea. The aims were: i) to define what the factors involved in Se bioaccumulation processes in the bivalve are, ii) to characterize Se bioaccumulation at different biological organisation levels, iii) to investigate Se toxic effects. First experiments, carried out for short term exposure duration (3 days), have permitted to underline the importance of Se chemical speciation in bioaccumulation processes in C. fluminea. It has been shown that the organic form, seleno-methionine, was much more bio-available than the inorganic forms, selenite and selenate. Moreover, the route of transfer was determinant in those processes. Inorganic forms have been better extracted by trophic route, whereas seleno-methionine has been better extracted by the direct route. In our experimental conditions, ventilation of the bivalve has not been a limiting factor for Se bioaccumulation by the direct route, whereas it has been for bioaccumulation by the trophic route. Ventilation has been largely modified by the presence of dissolved selenite and seleno-methionine. We have shown that the kinetics of seleno-methionine bioaccumulation are much more fast than those of selenite. Moreover, when introduced as SeMet, internalized Se appeared to be relatively remanent in soft tissues of C. fluminea in comparison with Se internalized when introduced as selenite. Subcellular and molecular distributions of these forms were very different. Finally, it has been shown that seleno-methionine and selenite could generate weak alterations of the anti

  3. Cultes de fertilité chez les Drung du Yunnan (Chine Fertility Rituals among the Drung People of of Yunnan (China

    Directory of Open Access Journals (Sweden)

    Stéphane Gros

    2012-10-01

    Full Text Available L’absence, chez les Drung du Yunnan, de rituels clairement identifiables comme rituels territoriaux implique de se questionner sur l’articulation entre l’ancestralité, le territoire et le pouvoir politique dans le cadre d’un objectif rituel commun : l’obtention de la fertilité. Après une description de deux pratiques rituelles liées à cette notion de fertilité, le sacrifice de bovins et le culte aux montagnes, telles qu’elles coexistaient autrefois chez les Drung, l’auteur questionne les liens entre ces deux pratiques et leurs implications politiques respectives. Si ces deux rituels peuvent se définir comme des cultes à la fertilité, ils manifestent cependant un rapport différent au territoire dans sa définition politique. D’un côté le sacrifice manifeste un caractère dynamique et compétitif de la relation politique (lié au prestige sans réelle inscription spatiale, tandis que de l’autre le culte aux montagnes manifeste un fort ancrage territorial révélateur de l’ancienne structure politique hiérarchique dans laquelle les Drung se trouvaient intégrés sous l’autorité de chefs tibétains (considérés comme les anciens maîtres des lieux. À un autre niveau, ces deux cultes de fertilité cristallisent une relation plus complexe au territoire vu comme un espace communautaire au sein duquel s’articulent les relations entre hommes et esprits.Among the Drung of Yunnan, the absence of any clearly identifiable territorial rituals calls into question the relationship between ancestrality, territory and political power within the framework of a common ritual goal : achieving fertility. This article presents an ethnographic description of two rituals associated with the notion of fertility—the ox sacrifice and the mountain cult—that used to coexist in Drung society. The links between these two rituals and their respective political implications are thus explored. While both rituals can be defined as

  4. Circadian long call distribution in wild orangutans Distribution circadienne des cris longs (long calls chez l’orang-outan en milieu naturel

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    Thomas Geissmann

    2009-10-01

    Full Text Available We present first data on circadian long call distribution of wild orangutans in Northwest Borneo. Data were collected during two months in Batang Ai National Park. A total of 151 male long calls were heard, exhibiting a bimodal distribution pattern with peaks at 05:00-06:00 hours and 18:00-19:00 hours. An earlier study found pronounced differences between the calling rates of Bornean orangutans, which showed an almost unimodal call distribution with its peak at mid-morning, and those of Sumatran orangutans, which showed a bimodal call distribution with a distinct calling peak at predawn and a more moderate peak near dusk (MacKinnon 1974. Our findings from Batang Ai resemble more closely the pattern reported for Sumatra than those reported for other Bornean localities and, therefore, contradict earlier reports suggesting a Sumatra-Borneo dichotomy in orangutan call distribution. In addition, orangutans in Batang Ai were heard to regularly emit long calls throughout the night. This behaviour is unusual for a diurnal species.Nous présentons les premières données sur la distribution circadienne des cris longs (long calls chez les mâles orangs-outans vivant en milieu naturel au nord-ouest de Bornéo. Les données ont été récoltées lors d’une étude de terrain de deux mois au Parc National de Batang Ai. Les 151 cris longs entendus montraient une distribution bimodale, caractérisée par des pics à 05:00-06:00 et 18:00-19:00 heures. Une étude précédente avait révélé des différences profondes entre les taux de cris longs des orangs-outans de Bornéo et de Sumatra. Alors que la distribution des cris longs à Bornéo était presque unimodale et montrait un pic en milieu d’avant-midi, la distribution à Sumatra était bimodale et montrait un pic distinct avant l’aube et un second pic plus modéré au crépuscule (MacKinnon 1974. Nos résultats à Batang Ai ressemblent davantage au schéma rapporté précédemment à Sumatra qu

  5. Prises de risques chez les jeunes de Bobo Dioulasso: une analyse des facteurs associés à la précocité et au multipartenariat sexuel

    Science.gov (United States)

    Adohinzin, Clétus Come; Meda, Nicolas; Belem, Adrien Marie Gaston; Ouédraogo, Georges Anicet; Sombie, Issiaka; Berthe, Abdramane; Fond-Harmant, Laurence

    2016-01-01

    Introduction Malgré les efforts d'éducation à la santé, les jeunes continuent d'adopter des comportements sexuels à risques, susceptibles d'avoir des répercussions importantes sur leur santé. Cette étude visait à analyser les facteurs associés à la précocité sexuelle et au multipartenariat chez les jeunes de 19-24 ans de Bobo-Dioulasso. Méthodes Il s'agit d'une étude quantitative et transversale. Les données d'enquête ont été recueillies en décembre 2014 à Bobo-Dioulasso (Burkina Faso), auprès de 573 jeunes de 15 à 24 ans. Ces enquêtés ont été sélectionnés par un sondage en grappes à deux degrés. Des facteurs à risques relatifs à la précocité sexuelle et au multipartenariat ont été analysés à l'aide du logiciel Stata IC 13. Le seuil de signification de Psexe, le niveau d'étude, et la situation économique des parents. Nos données avaient aussi montré que les rapports sexuels trop précoces étaient associés au multipartenariat sexuel (p<0,005). Conclusion Les actions visant à renforcer les capacités des jeunes à retarder les premiers rapports sexuels et à mieux évaluer les risques seront de toute importance. Les capacités des parents, des enseignants et des prestataires devraient être aussi renforcées pour l'amélioration de la qualité des relations entre eux et les jeunes. PMID:28292094

  6. Ostentation et refus du travail chez Veblen : le cas des jeunes chômeurs et de la spécificité militaire

    Directory of Open Access Journals (Sweden)

    Sébastien Schehr

    2007-10-01

    Full Text Available Cette contribution entend interroger la notion de « refus du travail » chez Veblen, notamment dans son rapport à l’ostentation et à la symbolique des places. Elle comportera deux parties : la première où sera exposée et revisitée la thèse de Veblen sur la fonction du refus du travail comme signe distinctif de la classe de loisir ; la deuxième où nous confronterons l’héritage de Veblen à des phénomènes sociaux contemporains. À cette fin, nous nous appuierons sur le rapport au travail des jeunes chômeurs et, dans une moindre mesure, sur celui des militaires, pour montrer que le refus du travail reste un principe opératoire de différenciation des groupes sociaux.This article intends to evaluate the notion of “work refusal” which can be found within Veblen’s work about conspicuous consumption and the symbolic of places. This article is divided in two parts. First, we will expose and revise Veblen’s thesis about the function of “work refusal” as a distinctive mark of the Leisure Class. Secondly, we will confront Veblen’s heritage to contemporary social phenomenon. For that reason, we will study the cases of the relationship of employed youth to work and the military. We will show that the refusal work stays a main principle of differentiation within social groups.

  7. Variable dimensionality and new uranium oxide topologies in the alkaline-earth metal uranyl selenites AE[UO2)(SeO3)2] (AE=Ca, Ba) and Sr[UO2)(SeO3)2] · 2H2O

    International Nuclear Information System (INIS)

    Almond, Philip M.; Peper, Shane M.; Bakker, Eric; Albrecht-Schmitt, Thomas E.

    2002-01-01

    Three new alkaline-earth metal uranyl selenites, Ca[UO 2 )(SeO 3 ) 2 ] (1), Sr[UO 2 )(SeO 3 ) 2 ] · 2H 2 O (2), and Ba[UO 2 )(SeO 3 ) 2 ] (3), have been prepared from the reactions of CaCO 3 and Ca(OH) 2 , SrCl 2 and Sr(OH) 2 , or BaCl 2 and Ba(OH) 2 with UO 3 and SeO 2 under mild hydrothermal conditions. Single-crystal X-ray diffraction experiments reveal that the structures of 1-3 differ in both connectivity and dimensionality even though all contain the same fundamental building unit, namely [UO 2 (SeO 3 ) 4 ]. This polyhedron consists of a linear uranyl unit that is bound by one chelating and three bridging selenite anions creating a pentagonal bipyramidal environment around the U(VI) center. The crystal structure of 1 contains one-dimensional ribbons where the edges are terminated by monodentate selenite anions. The interior of the ribbons are constructed from edge-sharing pentagonal bipyramidal UO 7 units. The structure of 2 is also one-dimensional; however, here there are chains of edge-sharing pentagonal bipyramidal UO 7 dimers that are connected by bridging selenite anions. Ba[(UO 2 )(SeO 3 ) 2 ] (3) is two-dimensional, and the highly ruffled anionic sheets present in this structure are formed from both bridging and chelating/bridging selenite anions bound to uranyl moieties. The anionic substructures in 1-3 are separated by Ca 2+ , Sr 2+ , or Ba 2+ cations. Crystallographic data (193 K, MoKα, λ=0.71073): 1, triclinic, space group P1-bar, a=5.5502(6) A, b=6.6415(7) A, c=11.013(1) A, α=104.055(2) deg., β=93.342(2) deg., γ=110.589(2) deg. , Z=2, R(F)=4.56% for 100 parameters with 1530 reflections with I>2σ(I); 2, triclinic, space group P1-bar, a=7.0545(5) A, b=7.4656(5) A, c=10.0484(6) A, α=106.995(1) deg., β=108.028(1) deg., γ=98.875(1) deg., Z=2, R(F)= 2.43% for 128 parameters with 2187 reflections with I>2σ(I); 3, monoclinic, space group P2 1 /c, a=7.3067(6) A, b=8.1239(7) A, c=13.651(1) A, β=100.375(2) deg., Z=4, R(F)=4.31% for 105 parameters

  8. Exploring the value of mixed methods within the At Home/Chez Soi housing first project: a strategy to evaluate the implementation of a complex population health intervention for people with mental illness who have been homeless.

    Science.gov (United States)

    Macnaughton, Eric L; Goering, Paula N; Nelson, Geoffrey B

    2012-05-02

    This paper is a methodological case study that describes the At Home/Chez Soi (Housing First) Initiative's mixed-methods strategy for implementation evaluation and discusses the value of these methods in evaluating the implementation of such complex population health interventions. The Housing First (HF) model is being implemented in five cities: Vancouver, Winnipeg, Toronto, Montréal and Moncton. At Home/Chez Soi is an intervention trial that aims to address the issue of homelessness in people with mental health issues. The HF model emphasizes choices, hopefulness and connecting people with resources that make a difference to their quality of life. A component of HF is supported housing, which provides a rent subsidy and rapid access to housing of choice in private apartments; a second component is support. Quantitative and qualitative methods were used to evaluate HF implementation. The findings of this case study illustrate how the critical ingredients of complex interventions, such as HF, can be adapted to different contexts while implementation fidelity is maintained at a theoretical level. The findings also illustrate how the project's mixed methods approach helped to facilitate the adaptation process. Another value of this approach is that it identifies systemic and organizational factors (e.g., housing supply, discrimination, housing procurement strategy) that affect implementation of key elements of HF. In general, the approach provides information about both whether and how key aspects of the intervention are implemented effectively across different settings. It thus provides implementation data that are rigorous, contextually relevant and practical.

  9. Determination of the total blood volume of the rat using chromium 51 (1962); Determination du volume sanguin total chez le rat a l'aide du chrome 51 (1962)

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, Y; Rinaldi, R [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1962-07-01

    In various experiments it is important that the rat's blood volume should be known and it is essential that it could be worked out by simply weighing the animal. Therefore authors decided to work out systematically with chromium 51 blood volume for rats with different weights. Results have shown that blood volume for 100 g is 5.55 ml and that it does not seen to vary with the weight of animals. (authors) [French] La connaissance de la masse sanguine chez le rat est indispensable dans de nombreuses experiences et il est essentiel de pouvoir l'evaluer apres une simple pesee de l'animal. C'est dans ce but que les auteurs ont entrepris la determination systematique de la masse sanguine a l'aide du chrome 51 chez des rats de poids differents. Les resultats obtenus ont montre que la masse sanguine rapportee a 100 grammes d'animal est de 5,53 millilitres, et qu'elle ne parait pas varier avec le poids de l'animal. (auteurs)

  10. Effets du conditionnement en jours longs à la fin du cycle reproducteur sur la période d'ovulation et sur les sécrétions gonadotropes chez l'omble chevalier (Salvelinus alpinus

    Directory of Open Access Journals (Sweden)

    GILLET C.

    1998-07-01

    Full Text Available Les ombles chevaliers originaires du Léman se reproduisent à la fin de l'automne. En élevage, il est intéressant de retarder de quelques mois la période des ovulations car ce poisson a besoin d'une température inférieure à 6°C pendant l'ovulation. Il est plus facile de fournir une eau à cette température aux géniteurs retardés qui ovulent en hiver qu'à ceux qui ovulent naturellement en automne. Le conditionnement des ombles chevaliers en jours longs (17L-7N pendant l'automne permet de retarder de plusieurs mois la période des ovulations. Cette méthode a l'inconvénient de provoquer un étalement des ovulations sur plus de 3 mois. Le reconditionnement des géniteurs en jours courts en décembre supprime ce problème. L'efficacité du traitement en jours longs ne semble pas dépendre de la durée de son application pourvu que celle-ci dépasse 1,5 mois. Chez les femelles conditionnées en jours longs en automne et en hiver, les concentrations en gonadotropine plasmatique (GTH II sont très faibles. Le niveau de la GTH II plasmatique augmente trois semaines après un transfert en jours courts en janvier. Les concentrations de la GTH II plasmatique au cours de l'ovulation sont significativement plus faibles chez les femelles conditionnées en jours longs en janvier que chez les animaux reconditionnés en jours courts. A ce stade du cycle reproducteur, la GTH I plasmatique reste toujours à un niveau très faible, quel que soit le régime photopériodique. La pose d'implant de mélatonine chez les poissons ne modifie pas les sécrétions gonadotropes en jours longs comme en jours courts. La réceptivité hypophysaire des femelles à une stimulation de la sécrétion gonadotrope par une injection de GnRH n'est pas modifiée par le conditionnement des poissons en jours longs. Aucun effet du pimozide sur la sécrétion de la GTH II n'a pu être mis en évidence chez les géniteurs conditionnés en jours longs. Ces résultats permettent

  11. Etude du pronostic maternel et périnatal au cours de l’accouchement chez l’adolescente à Lubumbashi, République Démocratique du Congo

    Science.gov (United States)

    Luhete, Prosper Kakudji; Mukuku, Olivier; Tambwe, Albert Mwembo; Kayamba, Prosper Kalenga Muenze

    2017-01-01

    Introduction L’objectif de cette étude était de déterminer la fréquence et d’évaluer le pronostic maternel et périnatal lors de l’accouchement chez les adolescentes dans la ville de Lubumbashi. Méthodes C’était une étude cas-témoin des accouchées d’une grossesse monofoetale de Décembre 2013 à Mai 2014 dans 10 maternités de référence à Lubumbashi (RD Congo). Les adolescentes (adolescentes était de 7,7%. Nous avons observé que la césarienne (ORa=1,9 (1,1-3,1)), l’épisiotomie (ORa=4,2 (2,9-5,9)), la délivrance pathologique (ORa= 2,7 (1,1-6,5)), l’éclampsie (ORa= 4,4 (1,3-14,5)) et le faible poids de naissance (ORa=2,0 (1,3-3,0)) ont été significativement plus élevés chez les adolescentes que chez les adultes. Conclusion L’accouchement chez les adolescentes, comparativement à celui de femmes âgées de 20-34 ans, reste associé à un mauvais pronostic. D’où l’organisation des séances de sensibilisation pour une meilleure fréquentation des services consultations prénatales, une optimisation du dépistage, de la surveillance et de la prévention des pathologies de la grossesse chez les adolescentes s’avère importante et urgente. Introduction This study aimed to determine the frequency and to assess maternal and perinatal prognosis for vaginal delivery in adolescent girls in the city of Lubumbashi. Methods We conducted a case-control study of vaginal deliveries in singleton pregnancy in 10 referral hospitals in Lubumbashi (DR Congo) from December 2013 to May 2014. Adolescent girls (< 20 years) were compared to older women aged 20-34 years. Maternal sociodemographic parameters, morbi-maternal and perinatal mortality were analyzed. Usual statistics and logistic regression were used to analyze the results. The significance level was set at p <0.05. Results Vaginal delivery rate among adolescent girls was 7.7%. Cesarean section (OR=1.9 (1.1-3.1)), episiotomy (OR=4.2 (2.9-5.9)), pathological delivery (OR=2.7 (1

  12. Efficacité de l’outil CANRISK pour détecter la dysglycémie chez les membres des Premières Nations et les Métis au Canada

    Directory of Open Access Journals (Sweden)

    Gina Agarwal

    2018-01-01

    Full Text Available Introduction : Le diabète touche en plus grande proportion et à un plus jeune âge la population des Premières Nations et des Métis que le reste de la population canadienne. Cet article vise principalement à évaluer l’efficacité et les scores de risque de CANRISK (Questionnaire canadien sur le risque de diabète, un outil de dépistage du diabète destiné aux Canadiens de 40 ans et plus pour détecter la dysglycémie chez les participants issus des Premières Nations et d’origine métisse en incluant les moins de 40 ans. L’objectif secondaire de cette étude est de déterminer si une modification des seuils relatifs au tour de taille (TT et à l’indice de masse corporelle (IMC améliore la valeur prédictive de modèles de régression logistique lorsque les variables du questionnaire CANRISK sont utilisées pour prédire la dysglycémie. Méthodologie : Nous avons recueilli auprès de 1479 participants métis et des Premières Nations des données provenant d’un questionnaire CANRISK autoadministré, de mesures anthropométriques et de résultats d’épreuve standard d’hyperglycémie provoquée par voie orale (HGPO. Nous avons calculé la sensibilité et la spécificité des scores CANRISK en appliquant les seuils usuels de classification des risques. Une régression logistique a été effectuée en utilisant des seuils tenant compte de l’origine ethnique pour l’IMC et le TT pour prédire la dysglycémie à l’aide des variables CANRISK. Résultats : Appliqué aux résultats de l’épreuve d’HGPO, le score seuil CANRISK à 33 points a conduit à une sensibilité et une spécificité de l’outil CANRISK de respectivement 68 % et 63 % chez les 40 ans et plus, et de respectivement 27 % et 87 % chez les moins de 40 ans. L’utilisation d’un seuil inférieur, à 21 points, a fait monter à 77 % la sensibilité chez les moins de 40 ans, avec une spécificité de 44 %. Malgré la faible spécificité correspondant à ce

  13. Le plurilinguisme textuel et les mécanismes de sa mise en œuvre chez Ahmadou Kourouma et Patrick Chamoiseau Le plurilinguisme textuel et les mécanismes de sa mise en oeuvre chez Ahmadou Kourouma et Patrick Chamoiseau

    Directory of Open Access Journals (Sweden)

    El hadji Camara

    2011-12-01

    Full Text Available Parler du plurilinguisme textuel dans le roman francophone, c’est poser la question du choix de la langue d’écriture chez l’écrivain francophone, mais aussi c’est évoquer à la fois les éléments constitutifs qui participent de la définition même de la littérature francophone. Par définition, un écrivain francophone c’est celui qui écrit en français peut-on dire de manière tautologique. Mais cette définition passe sous silence la dimension institutionnelle voire idéologique à l’œuvre dans la constitution de tout groupe social. Ainsi, selon Dominique Combe, les écrivains francophones forment un groupe bien distinct dans lequel des hommes et des femmes « expriment le sentiment d’appartenir, à travers la langue française, à une communauté de pensée, de culture. » (Combe, 1995 :14. Cependant, il faut reconnaître que tout texte possède sa propre identité, par ses langues et ses référents extratextuels, que ceux-ci soient ceux de l’auteur ou non. Dès lors, comment distinguer la langue de l’auteur de celle du texte ? Et dans quelles mesures les mécanismes de la mise en texte des langues concourent à la production du sens dans l’œuvre ? Alors qu’Ahmadou Kourouma se vante de faire parler ses personnages dans la langue de leur milieu social et culturel, Patrick Chamoiseau, se qualifiant lui-même de marqueur de parole, affirme retranscrire les paroles du conteur. Dès lors, à travers une approche comparative, il sera question dans cette communication d’analyser chez ces deux écrivains francophones, Ahmadou Kourouma et Patrick Chamoiseau en l’occurrence, comment cette textualisation des langues est mise en pratique dans leurs écritures.Parler du plurilinguisme textuel dans le roman francophone, c’est poser la question du choix de la langue d’écriture chez l’écrivain francophone, mais aussi c’est évoquer à la fois les éléments constitutifs qui participent de la définition même de

  14. L’évaluation du syndrome du Burnout chez les médecins en formation au CHU Ibn Rochd de Casablanca

    Science.gov (United States)

    El Kettani, Assiya; Serhier, Zineb; Othmani, Mohammed Bennani; Agoub, Mohamed; Battas, Omar

    2017-01-01

    Introduction Le Burnout est très répandu en milieu hospitalier et sa gravité est encore plus accrue chez les jeunes médecins. L'objectif est de déterminer la prévalence du burnout parmi les médecins en formation (internes et résidents) au CHU Ibn Rochd de Casablanca et chercher les facteurs associés. Méthodes Étude transversale descriptive menée en 2013- 2014 auprès d'un échantillon de 300 médecins à l'aide d'un questionnaire auto-administré; le burnout était évalué par la version française du Maslash Burnout Inventory (MBI). Résultats Un total de191 médecins a participé à l'étude (taux de réponse à 63,7%) avec une prédominance féminine à 79,1% et une moyenne d'âge de 26,7ans (ET = 3). Les scores moyens des sous-dimensions du MBI: l'épuisement émotionnel, la dépersonnalisation et l'accomplissement personnel étaient respectivement de (33,7 ± 10,7), (12,2 ± 6,5) et (30,6 ± 8,3). Le burnout sévère touchait 31,8% des participants. Il était associé aux problèmes de communication au sein de l'équipe soignante (p burnout sévère (p Burnout is very widespread in the hospital setting and it becomes much more severe in young physicians. The objective of this study aims to evaluate the prevalence of burnout among doctors in training (internal and residents) at the Ibn Rochd University Hospital, Casablanca and to identify factors associated with it. PMID:28979644

  15. L’apprentissage du bien-être animal chez de futures professionnels animaliers : des éthiques animals malmenées

    Directory of Open Access Journals (Sweden)

    Vidal Michel

    2015-01-01

    Full Text Available Les débats dont le bien-être animal est l’objet entre chercheurs, professionnels et associations en font une question socialement vive scientifico-éthique. Ils en interrogent l’éducabilité alors que cette notion est prise en compte dans les curricula de l’enseignement agricole. Envisageant son enseignement au travers d’une éducation à l’empathie interspécifique, nous questionnons les facteurs susceptibles de l’influencer. Nous nous fondons sur le discours de sept élèves en baccalauréat professionnel relevant de l’élevage d’animaux de production ou d’animaux de compagnie durant deux années de formation. Six élèves, quelle que soit leur filière de formation, souhaitent créer une relation affective sans nécessairement développer une attitude empathique durant la formation. Parmi les facteurs responsables, nous distinguons (1 un manque de confiance en soi de l’élève, (2 des motivations égocentrées primant sur des motivations zoocentrées, (3 la loyauté et les habitudes acquises à l’égard des pratiques parentales, (4 la conformation aux pratiques et idéologies dominantes du monde professionnel, (5 des facteurs associés aux situations d’enseignement (savoirs et pratiques de référence qui font autorité, valeurs de conformité primant sur des valeurs éthiques, dissociation de la dimension relationnelle et productive de l’élevage, jugements négatifs portés par l’enseignant et les élèves originaires du monde agricole. Ces facteurs généreraient des mécanismes de défense chez l’élève nuisibles au développement d’un raisonnement affectivo-éthique critique.

  16. Ending homelessness among people with mental illness: the At Home/Chez Soi randomized trial of a Housing First intervention in Toronto

    Directory of Open Access Journals (Sweden)

    Hwang Stephen W

    2012-09-01

    Full Text Available Abstract Background The At Home/Chez Soi (AH/CS Project is a randomized controlled trial of a Housing First intervention to meet the needs of homeless individuals with mental illness in five cities across Canada. The objectives of this paper are to examine the approach to participant recruitment and community engagement at the Toronto site of the AH/CS Project, and to describe the baseline demographics of participants in Toronto. Methods Homeless individuals (n = 575 with either high needs (n = 197 or moderate needs (n = 378 for mental health support were recruited through service providers in the city of Toronto. Participants were randomized to Housing First interventions or Treatment as Usual (control groups. Housing First interventions were offered at two different mental health service delivery levels: Assertive Community Treatment for high needs participants and Intensive Case Management for moderate needs participants. Demographic data were collected via quantitative questionnaires at baseline interviews. Results The effectiveness of the recruitment strategy was influenced by a carefully designed referral system, targeted recruitment of specific groups, and an extensive network of pre-existing services. Community members, potential participants, service providers, and other stakeholders were engaged through active outreach and information sessions. Challenges related to the need for different sectors to work together were resolved through team building strategies. Randomization produced similar demographic, mental health, cognitive and functional impairment characteristics in the intervention and control groups for both the high needs and moderate needs groups. The majority of participants were male (69%, aged >40 years (53%, single/never married (69%, without dependent children (71%, born in Canada (54%, and non-white (64%. Many participants had substance dependence (38%, psychotic disorder (37%, major depressive episode (36

  17. Aspects descriptifs du VIH/SIDA chez les sujets âgés de 50 ans et plus suivis au Centre de Traitement Agréé de Bafoussam - Cameroun

    Science.gov (United States)

    Mbopi-Kéou, François-Xavier; Djomassi, Lucienne Dempouo; Monebenimp, Francisca

    2012-01-01

    Introduction La littérature scientifique dispose de très peu de données relatives à l’épidémiologie du VIH chez les sujets âgés en Afrique subsaharienne. Au Cameroun, les caractéristiques épidémiologiques de l'infection par le VIH chez les sujets âgés de 50 ans et plus ne sont pas documentées. Méthodes Dans une étude de cohorte rétrospective et une enquête transversale, nous avons comparé les caractéristiques clinico-biologiques et la survie post thérapeutique des patients âgés de 50 ans et plus, sous traitement antirétroviral au Centre de Traitement Agrée de Bafoussam - Cameroun, aux adultes plus jeunes. Résultats L’âge moyen était de 39 ans, les extrêmes étant 17 et 88 ans. Les sujets âgés de 50 ans et plus représentaient 14,1% des cas. Les plus âgés étaient moins bien informés sur les modes de transmission du virus (p = 0,04). Leur séropositivité au VIH était le plus souvent découverte au décours d'une infection opportuniste (p = 0,02). La fréquence de comorbidité était significativement plus élevée chez les personnes âgées de 50 ans et plus (p VIH. La promotion du dépistage et les programmes d’éducation sanitaire relatifs au VIH/SIDA devraient être renforcés au sein de cette communauté déjà affaiblie par le poids de l’âge, afin de réduire l'incidence du SIDA et de leur assurer prise en charge précoce. PMID:23133707

  18. XAS studies on selenite reduction by pyrite

    International Nuclear Information System (INIS)

    Kang Mingliang; Liu Chunli; Chen Fanrong; Charlet, Laurnet

    2012-01-01

    The interaction of aqueous Se (IV) with pyrite were systematically investigated in light of thermodynamic calculations and X-ray Absorption Spectroscopy (XAS). The results from the speciation study reveal that the reduction product is Se (O) when natural pyrite reacts with Se (N) at pH≤5.65, while small amount of FeSeO 3 or iron selenides may be formed at pH 6.1. At pH≥6.94, due to the precipitation of Fe (Ⅲ) -oxyhydroxide, the formation of the thermodynamically most stable species, FeSe 2 , is inhibited. However, when the reactive nanopyrite-greigite was used for reaction, the thermodynamically most stable species, FeSe 2 , was found for the first time as the predominant product in the present study, suggesting that 79 Se can be immobilized in its most insoluble form, FeSe 2 , in Fe (Ⅱ) -sulfide containing environment. This study confirms that pyrite can significantly attenuate the mobility of Se by reductive precipitation, and that the reaction process does not produce protons under acidic or neutral condition when Se (O) is formed. (authors)

  19. Short range order of selenite glasses

    Czech Academy of Sciences Publication Activity Database

    Neov, Dimitar; Gerasimova, I.; Yordanov, S.; Lakov, L.; Mikula, Pavol; Lukáš, Petr; Dimitriev, Y.

    1999-01-01

    Roč. 40, č. 2 (1999), s. 111-112 ISSN 0031-9090 R&D Projects: GA ČR GV202/97/K038; GA AV ČR KSK1048601 Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.822, year: 1999

  20. Avaliação do efeito radioprotetor do selenito de sódio no processo de reparação tecidual em ratos Evaluation of the radioprotective effect of sodium selenite in the tissue repair process in rats

    Directory of Open Access Journals (Sweden)

    Fabrício M. Tuji

    2005-09-01

    Full Text Available OBJETIVO: Avaliar a ação radioprotetora do selenito de sódio no processo de reparação tecidual. MATERIAIS E MÉTODOS: Ratos Wistar foram submetidos a procedimento cirúrgico para a realização de ferida na região dorsal. Os animais foram divididos em quatro grupos experimentais: controle, selênio, irradiado e selênio-irradiado. Os grupos selênio e selênio-irradiado receberam 2,0 mg/kg de selenito de sódio, 48 horas após a cirurgia. Os grupos irradiado e selênio-irradiado foram submetidos à irradiação em dose única de 6 Gy, administrada somente nas bordas das feridas. Após 4, 7, 13 e 21 dias do procedimento cirúrgico, os animais foram sacrificados e avaliados por meio de análise morfológica, histoquímica e birrefringência do tecido. RESULTADOS: O aspecto estrutural e morfológico, assim como a qualidade do tecido e sua maturação através da quantidade e disposição dos feixes de fibras colágenas, juntamente com o seu grau de orientação macromolecular, permitiu observar a presença de intenso retardo provocado pela irradiação, bem como o efeito radioprotetor do selenito de sódio no processo de reparação. CONCLUSÃO: Dentro das condições experimentais utilizadas, o selenito de sódio apresentou-se como radioprotetor eficaz, visto que o processo de reparação no grupo selênio-irradiado comportou-se, histologicamente, semelhante ao grupo controle.OBJECTIVE: To evaluate the radioprotective effect of sodium selenite in the tissue repair process. MATERIALS AND METHODS: Male Wistar rats submitted to a surgical procedure to produce a wound in the dorsal region. These animals were then divided in four experimental groups: control, selenium, irradiated and selenium-irradiated. The selenium and selenium-irradiated groups received sodium selenite (2.0 mg/kg, 48 hours after surgery. The irradiated and selenium-irradiated groups received a single dose of 6 Gy, administered only in the borders of the wound. The animals were

  1. Synthesis and crystal structure of new uranyl selenite(IV)-selenate(VI) [C5H14N][(UO2)3(SeO4)4(HSeO3)(H2O)](H2SeO3)(HSeO4)

    International Nuclear Information System (INIS)

    Krivovichev, S.V.; Tananaev, I.G.; Myasoedov, B.F.; Kalenberg, V.

    2006-01-01

    Crystals of new uranyl selenite(IV)-selenate(VI) [C 5 H 14 N][(UO 2 ) 3 (SeO 4 ) 4 (HSeO 3 )(H 2 O)](H 2 SeO 3 )(HSeO 4 ) are obtained by the method of evaporation from aqueous solutions. Compound has triclinic lattice, space group P1-bar, a=11.7068(9), b=14.8165(12), c=16.9766(15), α=73.899(6), β=76.221(7), γ=89.361(6) Deg, V=2743.0(4) A 3 , Z=2. Laminated complexes (UO 2 ) 3 (SeO 4 ) 4 (HSeO 3 )(H 2 O)] 3- are the basis of the structure. [HSe(VI)O 4 ] - , [H 2 Se(IV)O 3 ] complexes and protonated methylbutylamine cations are disposed between layers [ru

  2. Pour une comparaison des utilisations atypiques des constructions verbales chez les locuteurs bilingues anglais/français et anglais/allemand

    Directory of Open Access Journals (Sweden)

    Brasart, Charles

    2013-09-01

    lesquelles un verbe se voit affublé d'une désinence issue d'une autre langue, elles ont souvent été considérées illicites, c'est-à-dire ne pouvant être produites spontanément par les locuteurs, et font encore débat (POPLACK , 1980, MACSWAN, 1999, SEBBA, 2009. Malgré cela, une analyse du traitement du verbe chez les bilingues fondée sur l'étude de deux corpus oraux nous conduit à postuler que c'est souvent l'inverse qui se produit. En effet, chez les locuteurs bilingues français/anglais et anglais/allemand dont la pratique discursive est analysée pour cette étude, le groupe verbal semble être un lieu privilégié du passage d'une langue à l'autre et, de plus, ce passage prend des formes diverses et qui sont souvent similaires d'un couple de langue à un autre. C'est peut-être là d'ailleurs que se situe l'un des éléme nts phares dégagés par cette étude, à savoir que dans deux paires de langues se retrouvent des tendances syntaxiques et grammaticales communes. Nous souhaitons ainsi montrer que les locuteurs bilingues peuvent faire un usage similaire d'outils différents pour arriver au même but --communiquer un message précis --, quelles que soient les langues parlées. Après avoir présenté la méthodologie de la recherche dans le domaine de l'alternance codique, nous prendrons pour exemples les cas où les grammaires des deux langues en jeu sont rendues compatibles entre elles par divers " bricolages " syntaxiques, produisant des énoncés qui, en regard de la grammaire de chaque langue, seraient fautifs. Nous poursuivrons en nous penchant sur des énoncés où la rencontre des langues permet d'associer des propriétés qui n'existent que dans l'une ou l'autre. Ceci sera également l'occasion d'analyser les conflagrations morphologiques, dans lesquelles des désinences de langue X sont associées à des bases verbales de langue Y. Nous montrerons qu'il n'existe pas de systématicité dans l'utilisation ou non de ces conflagrations par les

  3. L’évaluation systématique des instruments pour mesurer la douleur chez les personnes âgées ayant des capacités réduites à communiquer*

    OpenAIRE

    Aubin, Michèle; Giguère, Anik; Hadjistavropoulos, Thomas; Verreault, René

    2007-01-01

    La douleur chronique est souvent sous-détectée et insuffisamment traitée dans les milieux de soins de longue durée. Les outils d’autorapport (ou autoévaluation) de la douleur, comme l’échelle visuelle analogique, n’ont été validés que partiellement chez les populations âgées, en raison de la prévalence élevée de déficits visuels, auditifs, moteurs et cognitifs que l’on y trouve. Des outils d’observation des patients ont été développés pour pallier ces difficultés d’utilisation des échelles d’...

  4. La variabilité génétique chez l'huître plate Ostrea edulis (L. 1758) : inférence du nombre de géniteurs instantané d'une population

    OpenAIRE

    Da Silva, Sara Maria Mira

    2001-01-01

    Les études de génétique des populations des bivalves marins ont fréquemment mit en évidence une relation hétérozygotie / valeur sélective, et un fort déficit en hétérozygotes. Parmi les hypothèses explicatives de ces deux phénomènes, la création d'individus consanguins dans les populations est particulièrement intéressante à tester. Le but de ce travail était de vérifier s'il pouvait y avoir un nombre faible de géniteurs à la base d'un événement de reproduction donné chez l'huître plate Ostre...

  5. Révision systématique des effets de la fréquence des repas en famille sur les résultats psychosociaux chez les jeunes

    Science.gov (United States)

    Harrison, Megan E.; Norris, Mark L.; Obeid, Nicole; Fu, Maeghan; Weinstangel, Hannah; Sampson, Margaret

    2015-01-01

    Résumé Objectif Effectuer une révision systématique des effets de repas en famille fréquents sur les résultats psychosociaux chez les enfants et les adolescents et examiner s’il existe des différences dans les résultats selon le sexe. Sources des données Des études ont été cernées à la suite d’une recherche dans MEDLINE (de 1948 à la dernière semaine de juin 2011) et dans PsycINFO (de 1806 à la première semaine de juillet 2011) à l’aide de l’interface Ovide. Les expressions et mots clés MeSH utilisés seuls ou en combinaisons étaient les suivants : family, meal, food intake, nutrition, diets, body weight, adolescent attitudes, eating behaviour, feeding behaviour et eating disorders. Les bibliographies des articles jugés pertinents ont aussi été passées en revus. Sélection des études La recherche initiale a produit 1783 articles. Pour être incluses dans l’analyse, les études devaient répondre aux critères suivants : être publiées en anglais dans une revue révisée par des pairs; porter sur des enfants ou des adolescents; traiter de l’influence des repas en famille sur les paramètres psychosociaux (p. ex. consommation de drogues et autres substances, troubles de l’alimentation, dépression) chez les enfants ou les adolescents; avoir une conception d’étude appropriée, notamment des méthodes statistiques acceptables pour l’analyse des paramètres. Quatorze articles satisfaisaient aux critères d’inclusion. Deux examinateurs indépendants ont étudié et analysé les articles. Synthèse Dans l’ensemble, les résultats font valoir que la fréquence des repas en famille est inversement proportionnelle aux troubles de l’alimentation, à la consommation d’alcool et de drogues, aux comportements violents, aux sentiments de dépression ou aux pensées suicidaires chez les adolescents. Il existe une relation positive entre de fréquents repas en famille, une bonne estime de soi et la réussite scolaire. Les

  6. Identification des facteurs influençant la décision des avortements chez les bovins par les éleveurs et les vétérinaires

    OpenAIRE

    Bronner, Anne; Hénaux, Viviane; Fortané, Nicolas; Calavas, Didier

    2013-01-01

    Le dispositif de déclaration des avortements (DA), qui constitue actuellement en France l’une des modalités principales de la surveillance de la brucellose chez les bovins, présente un défaut avéré de sensibilité. Afin de mieux comprendre les raisons de cette sous-déclaration, une étude qualitative a été menée auprès de douze éleveurs et de huit vétérinaires sanitaires, sous forme d’entretiens semi-directifs. Le défaut de sensibilité du dispositif s’explique par la prise en compte par les éle...

  7. Synthèse bibliographique sur le comportement de recherche de l’hôte chez la punaise de lit (Cimex lectularius) et applications dans le cadre de la lutte intégrée

    OpenAIRE

    Legrand, Pauline; Verheggen, François; Haubruge, Eric; Francis, Frédéric

    2016-01-01

    Cette étude analyse le comportement de recherche de l’hôte chez la punaise de lit, Cimex lectularius, en portant une attention particulière sur les stimuli émis par l’Homme et impliqués dans ce processus d’orientation. Elle met également en évidence les applications possibles en matière de lutte intégrée. La punaise de lit est un ectoparasite exclusivement hématophage étroitement lié à l’Homme depuis des millénaires. Lors de sa recherche alimentaire, cet insecte utilise des stimuli émis pa...

  8. The Impact of a 24 Month Housing First Intervention on Participants' Body Mass Index and Waist Circumference: Results from the At Home / Chez Soi Toronto Site Randomized Controlled Trial.

    Directory of Open Access Journals (Sweden)

    Julia Woodhall-Melnik

    Full Text Available Research suggests that individuals experiencing homelessness have high rates of overweight and obesity. Unhealthy weights and homelessness are both associated with increased risk of poor health and mortality. Using longitudinal data from 575 participants at the Toronto site of the At Home/Chez Soi randomized controlled trial, we investigate the impact of receiving a Housing First intervention on the Body Mass Index (BMI and waist circumference of participants with moderate and high needs for mental health support services. The ANCOVA results indicate that the intervention resulted in no significant change in BMI or waist circumference from baseline to 24 months. The findings suggest a need for a better understanding of factors contributing to overweight, obesity, and high waist circumference in populations who have histories of housing precarity and experience low-income in tandem with other concerns such as mental illness and addictions.International Standard Randomized Control Trial Number Register ISRCTN42520374.

  9. ETUDE DE L'EFFET DE QUELQUES FACTEURS SUR LA CYTOTOXICITE INDUITE PAR L'AMPHOTERICINE B ASSOCIEE AUX LIPOPROTEINES DU SERUM SANGUIN CHEZ DES CELLULES DE GLOBULES ROUGES HUMAINES

    OpenAIRE

    BOUCHERIT, ATMANI Zahia

    2014-01-01

    toxiques. Dans le cadre de l'élaboration d'une stratégie de développement de cette molécule visant à augmenter l'index thérapeutique tout en réduisant la toxicité, nous avons étudié l'effet de quelques facteurs sur la cytotoxicité induite par l'amphotéricine B associée à des lipoprotéines du sérum sanguin chez le globule rouge humain (modèle universel de cellules animales supérieures). Dans notre travail nous avons abordé d'une part, les effets des caractéristiques des lipoprot...

  10. Détermination de quelques paramètres hématologiques chez les agriculteurs exposés aux pesticides dans la région de Tlemcen

    OpenAIRE

    SAIDI, Fatima Zohra

    2015-01-01

    Résumé Les pesticides représentent une large gamme de produits utilisés de façon très variable. Les agriculteurs sont aujourd'hui le groupe le plus exposé aux risques de contact avec les pesticides. L'objectif de notre travail consiste à mettre en évidence les altérations hématologiques chez les hommes agriculteurs disposés aux pesticides comparés aux hommes témoins. Un prélèvement sanguin est réalisé afin de déterminer quelques paramètres hématologiques (FNS, numérations cellu...

  11. The Impact of a 24 Month Housing First Intervention on Participants' Body Mass Index and Waist Circumference: Results from the At Home / Chez Soi Toronto Site Randomized Controlled Trial.

    Science.gov (United States)

    Woodhall-Melnik, Julia; Misir, Vachan; Kaufman-Shriqui, Vered; O'Campo, Patricia; Stergiopoulos, Vicky; Hwang, Stephen

    2015-01-01

    Research suggests that individuals experiencing homelessness have high rates of overweight and obesity. Unhealthy weights and homelessness are both associated with increased risk of poor health and mortality. Using longitudinal data from 575 participants at the Toronto site of the At Home/Chez Soi randomized controlled trial, we investigate the impact of receiving a Housing First intervention on the Body Mass Index (BMI) and waist circumference of participants with moderate and high needs for mental health support services. The ANCOVA results indicate that the intervention resulted in no significant change in BMI or waist circumference from baseline to 24 months. The findings suggest a need for a better understanding of factors contributing to overweight, obesity, and high waist circumference in populations who have histories of housing precarity and experience low-income in tandem with other concerns such as mental illness and addictions. International Standard Randomized Control Trial Number Register ISRCTN42520374.

  12. Variations morphologiques de l’appareil nucléaire chez les ciliés Astomes Almophrya bivacuolata et A. mediovacuolata (Protozoa : Ciliophora endocommensaux d’oligochètes terricoles du Cameroun

    Directory of Open Access Journals (Sweden)

    Nana P.A.

    2010-12-01

    Full Text Available L’imprégnation argentique complétée par la coloration nucléaire de Feulgen et la coloration au DAPI nous ont permis d’étudier les variations morphologiques de l’appareil nucléaire chez deux espèces de ciliés Astomes, Almophrya bivacuolata (de Puytorac et Dragesco, 1968 et A. mediovacuolata (Ngassam, 1983 endocommensaux. Nous avons mis en évidence d’importantes digitations et la présence de bandes sombres dans la structure du macronoyau en “H” des petits types cellulaires ainsi que la présence de formes intermédiaires entre “H” et “X” dans ces deux espèces.

  13. Contribution à l'évaluation de la pollution marine par le métaux lourds (Cd, Cu, Fe, Pb, Zn) chez la coralline (Corallina officinalis) de la baie de Ghazaouet (W. de Tlemcen)

    OpenAIRE

    DOUAHI, Somia

    2015-01-01

    Ce travail consiste à démontrer la présence des métaux lourds chez la coralline et cela dans le cadre d'une contribution a une étude de la bioaccumulation des éléments métallique dans le littoral de Ghazaouet. Cette étude quantitative permet d'une part de consolider les résultats des études antérieurs en démontrant la présence des métaux lourds dans le littoral, et d'autre part, de démontrer l'évolution quantitative de cinq polluants, notamment, le Cadmium, le cuivre, le fer...

  14. Effet de la pollution métallique littorale : effets pathologiques et mécanismes de détoxication chez des poissons marins d'intérêt commercial

    OpenAIRE

    Duquesne, Sabine

    1989-01-01

    Le but de cette étude (constituant la première partie d'un projet de recherche) est de démontrer si différentes espèces de poissons marins soumis à une pollution métallique littorale, assurent ou non leur détoxification par des métallothionéines (MTH). En effet, la présence de ce type de protéines, qui complexe les métaux, n'a été observée que chez quelques espèces de poissons marins; de plus, dans la plupart des cas, ces poissons ont été intoxiqués au laboratoire. (BOUQUEGNEAU et al., 1975 O...

  15. Study of the {sup 14}C benzimidazole distribution in mice after inter-peritoneal injection; Etude de la repartition du benzimidazole {sup 14}C chez la souris apres injection intraperitoneale

    Energy Technology Data Exchange (ETDEWEB)

    Tyortyalian, C [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1965-07-01

    In order to provide further information on the mechanism of benzimidazole radioprotective activity, this work studies the tissual repartition in mice of this compound labelled with carbon 14. Experiments have showed that benzimidazole distribution is fast and homogeneous in all the tissues, but however affinity appears at the level of stomach and gastric content. Elimination is made through the urinary system and is very fast. (author) [French] Dans le cadre de l'etude du mecanisme de l'action radioprotectrice du benzimidazole, ce travail a pour objet l'etude de la repartition tissulaire chez la souris de ce compose marque au carbone 14. L'experimentation a montre que le benzimidazole se repartit tres rapidement et de facon pratiquement homogene dans tous les tissus, avec toutefois une affinite paraissant se manifester au niveau de l'estomac et du contenu gastrique. L'elimination, qui se fait par voie urinaire, est tres rapide. (auteur)

  16. Les phlébotomes (Diptera-Psychodidae de l'île de Chypre.II - Presence de Leishmania (Leishmania infantum Nicolle, 1908 (zymodeme MON 1 chez Phlebotomus (Larroussius tobbi Adler et Theodor, 1930

    Directory of Open Access Journals (Sweden)

    Léger N.

    2000-06-01

    Full Text Available Dans le foyer leishmanien cypriote, les auteurs ont disséqué 2910 femelles de phlébotomes appartenant à 11 espèces : Phlebotomus papatasi, P. sergenti, P. jacusieli, P. alexandri, P. tobbi, P. galilaeus, P. mascittii, P. economidesi, Sergentomyia fallax, S. minuta et S. azizi . Les deux larroussius (P. galilaeus et P. tobbi sont les espèces les plus abondantes. Elles représentent plus de 60 % des captures réalisées avec des pièges CDC. Des promastigotes ont été observées chez un seul spécimen appartenant à l'espèce P. tobbi. Elles ont été mises en culture puis identifiées selon la méthode isoenzymatique. La souche de Leishmania isolée appartient à l'espèce Leishmania infantum, zymodème MON 1. Le même zymodème a été aussi isolé et identifié chez quatre chiens de l'île. En l'absence des vecteurs habituels de L. infantum dans l'est méditerranéen (P. neglectus ef P. syriacus et en raison de sa répartition à Chypre, P. tobbi constitue vraisemblablement un bon vecteur local. Sa faible anthropophilie expliquerait peut-être le très faible nombre de cas humains. Le rôle de P. galilaeus dans la transmission de la leishmaniose à Chypre reste à préciser.

  17. L’évaluation systématique des instruments pour mesurer la douleur chez les personnes âgées ayant des capacités réduites à communiquer*

    Science.gov (United States)

    Aubin, Michèle; Giguère, Anik; Hadjistavropoulos, Thomas; Verreault, René

    2007-01-01

    La douleur chronique est souvent sous-détectée et insuffisamment traitée dans les milieux de soins de longue durée. Les outils d’autorapport (ou autoévaluation) de la douleur, comme l’échelle visuelle analogique, n’ont été validés que partiellement chez les populations âgées, en raison de la prévalence élevée de déficits visuels, auditifs, moteurs et cognitifs que l’on y trouve. Des outils d’observation des patients ont été développés pour pallier ces difficultés d’utilisation des échelles d’autorapport de la douleur. Le présent projet vise l’identification de ces échelles et leur évaluation sur la base de la validité de contenu (12 questions), de la validité de construit (12 questions), de la fiabilité (13 questions) et de l’utilité clinique (10 questions). Parmi les 24 instruments recensés, plusieurs apparaissent prometteurs pour évaluer la douleur chez les personnes âgées atteintes de démence sévère. Des efforts additionnels de validation sont cependant requis avant leur intégration à la pratique régulière en soins de longue durée. PMID:17717611

  18. Une masculinité en crise à la fin du XVIIe siècle ? La critique de l'efféminé chez La Bruyère

    Directory of Open Access Journals (Sweden)

    Cédric Corgnet

    2008-07-01

    Full Text Available L’efféminé est toujours un cas sexuel limite : homme aux airs féminins, il interroge l’innée de la nature sexuelle, critique les genres et leur définition explicitement physique. La fin du XVIIe siècle illustre cette tension chez les moralistes français et surtout chez La Bruyère dans ses Caractères où celui-ci interroge cette monstruosité générique à travers une analyse sémiologique. Mais cette tératologie n’est pas avant tout clinique mais sociale et morale : il nous avertit, par cet écart de genre, d’une corruption morale du monde tant par une sémiologie clinique que mythologique ovidienne ne cherchant pas le réalisme pathologique mais la filiation antique qui ante son ouvrage sur les Caractères Théophrastiens : philosophe plus que naturaliste.The effeminate is always a sexual limit case: man in the feminine sights, he questions the innate of the sexual nature, criticizes genders and their explicitly physical definition. The end of the XVIIth century illustrates this tension at the French moralists and especially in La Bruyère’s Characters where this one questions this generic monstrousness through a semiological analysis. But this teratology is not above all clinical but social and moral: he warns us, by this distance from gender, from a moral corruption of the world both by a clinical semiology and ovidian mythology not looking for the pathological realism but the antic filiation with Theophrast’s Characters : philosopher more than naturalist.

  19. Variable dimensionality and framework found in a series of quaternary zinc selenites, A{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4}·xH{sub 2}O (A = Na, Rb, and Cs; 0≤x≤1) and Cs{sub 2}Zn{sub 2}(SeO{sub 3}){sub 3}·2H{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Lü, Minfeng; Jo, Hongil; Oh, Seung-Jin; Ok, Kang Min, E-mail: kmok@cau.ac.kr

    2017-01-15

    Five new alkali metal zinc selenites, A{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4}·xH{sub 2}O (A = Na, Rb, and Cs; 0≤x≤1) and Cs{sub 2}Zn{sub 2}(SeO{sub 3}){sub 3}·2H{sub 2}O have been synthesized by heating a mixture of ZnO, SeO{sub 2} and A{sub 2}CO{sub 3} (A = Na, Rb, and Cs), and characterized by X-ray diffraction (XRD) and spectroscopic analyses techniques. All of the reported materials revealed a rich structural chemistry with different frameworks and connection modes of Zn{sup 2+}. While Rb{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4} and Cs{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4}·H{sub 2}O revealed three-dimensional frameworks consisting of isolated ZnO{sub 4} tetrahedra and SeO{sub 3} polyhedra, Na{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4}, Cs{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4}, and Cs{sub 2}Zn{sub 2}(SeO{sub 3}){sub 3}·2H{sub 2}O contained two-dimensional [Zn{sub 3}(SeO{sub 3}){sub 4}]{sup 2-} layers. Specifically, whereas isolated ZnO{sub 4} tetrahedra and SeO{sub 3} polyhedra are arranged into two-dimensional [Zn{sub 3}(SeO{sub 3}){sub 4}]{sup 2-} layers in two cesium compounds, circular [Zn{sub 3}O{sub 10}]{sup 14-} chains and SeO{sub 3} linkers are formed in two-dimensional [Zn{sub 3}(SeO{sub 3}){sub 4}]{sup 2-} layers in Na{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4}. Close structural examinations suggest that the size of alkali metal is significant in determining the framework geometry as well as connection modes of transition metal cations. - Graphical abstract: Variable dimensions and frameworks were found in a series of quaternary zinc selenites, A{sub 2}Zn{sub 3}(SeO{sub 3}){sub 4} (A = Na, Rb and Cs). - Highlights: • Five novel quaternary zinc selenites are synthesized. • All the selenites with different structures contain polarizable d{sup 10} and lone pair cations. • The size of alkali metal cations is significant in determining the framework geometry.

  20. Corrélats du bien-être chez les Canadiens présentant des troubles de l’humeur ou d'anxiété

    Directory of Open Access Journals (Sweden)

    H. Orpana

    2016-01-01

    Full Text Available Introduction : Notre objectif visait à étudier les variables liées au bien-être, mesurées par une autoévaluation de la santé mentale (AESM très positive et une satisfaction élevée à l’égard de la vie (SV chez des adultes canadiens (âgés de 18 ans et plus présentant un trouble de l’humeur ou d'anxiété. Méthodologie : Nous avons utilisé des données nationales représentatives tirées de l’Enquête sur les personnes ayant une maladie chronique au Canada – Composante des troubles de l’humeur et d’anxiété (EPMCC-TAH de 2014 afin de décrire l’association entre bien-être et comportements d’autogestion (activité physique, sommeil et méditation ainsi que stress, adaptation et soutien social perçus. Nous avons eu recours à une régression logistique multivariée pour modéliser la relation entre ces facteurs et les mesures du bien-être. Résultats : Environ une personne sur trois atteinte d’un trouble de l’humeur ou d’anxiété a fait état d'une AESM positive. Les modèles de régression logistique ont révélé que plusieurs caractéristiques, comme un âge plus avancé, une autoévaluation de la santé générale positive, des limitations fonctionnelles moins nombreuses ainsi que la perception d’un moindre stress à l’égard de la vie, de meilleures capacités d’adaptation et d’un plus grand soutien social, étaient associées à des niveaux de bien-être plus élevés. Les comportements d’autogestion (entamer une activité physique, méditer, adopter de saines habitudes de sommeil et atteindre un certain nombre d’heures de sommeil chaque nuit n’étaient pas significativement associés à des mesures du bien-être dans notre modèle multivarié. Conclusion : Les adultes canadiens souffrant de troubles de l’humeur ou d'anxiété qui ont déclaré percevoir un niveau de stress plus faible, un plus grand soutien social et une meilleure capacité d’adaptation étaient plus susceptibles de

  1. Les dermites du siège chez le nourrisson à Dakar: Etude de 205 cas [Diaper dermatitis among the infant in Dakar: Study of 205 cases

    Directory of Open Access Journals (Sweden)

    Boubacar Ahy Diatta

    2017-11-01

    générale dans 3%. La dermite était séborrhéique dans 51,7%, mycosique dans 14,6% et associée à : une acrodermatite entéropathique dans 4cas et un granulome glutéal dans un cas. Les couches étaient utilisées dans 93,7% par les mamans avec un changement de moins de 6 fois par jour dans 84,9%. L’évolution clinique était favorable dans 56,1%. Conclusion: Les dermites du siège du nourrisson sont des dermatoses fréquentes chez le nourrisson à Dakar. Les causes multiples rendent nécessaire une démarche diagnostique rigoureuse. La gravité est liée à l’association avec des maladies générales.

  2. Par-delà l’interdit (haram. Une ethnographie du mariage et de la sexualité chez les Sahraouis du Sud marocain

    Directory of Open Access Journals (Sweden)

    Claire Cécile Mitatre

    2009-03-01

    Full Text Available Par-delà l’interdit (haram. Une ethnographie du mariage et de la sexualité chez les Sahraouis du Sud marocain. Avant de me rendre dans l’Oued Noun, région oasienne du pré-Sahara atlantique, mes lectures sur le monde musulman et le bassin méditerranéen me portaient à penser que, par le mariage, une femme entrait dans le haram de son mari, domaine de l’interdit qu’un galant ne peut enfreindre sans risquer d’être tué par l’époux offensé. Les premiers temps de mon expérience ethnographique, j’interprétais alors le caractère insouciant des invitations galantes que l’on pouvait me faire tout en me sachant mariée, comme une manière détournée d’affirmer que les Occidentaux n’avaient pas de domaine de l’interdit sur lequel étendre leur autorité, et de me renvoyer à mon statut d’étrangère. C’est cependant en prenant les avances des hommes à mon égard comme objet d’analyse que je compris comment, dans cette région présaharienne, le mariage constituait en réalité, pour la femme sahraouie, un rite d’accession aux relations de galanterie : par la perte rituelle de sa virginité, la femme s’affranchit du seul véritable haram auquel elle a jamais appartenu, celui de son père.Beyond the forbidden (haram. An ethnography of marriage and sexuality among the Sahraoui of Southern Morocco. Before going to the Oued Noun, an oasis region of the Atlantic pre-Sahara, my readings on the Muslim world and the Mediterranean basin led me to think that when she married, a woman entered the haram of her husband, a forbidden domain that an admirer can only infringe upon at the risk of being killed by the offended husband. At the beginning of my ethnographic experience, I interpreted the carefree nature of the amorous invitations I received from men who knew I was married as a roundabout way of affirming that Westerners have no forbidden domain to exert their authority over, and to remind me of my status as a

  3. Association entre le travail par quarts et l’obésité chez les hommes dans le nord-est de l’Ontario

    Directory of Open Access Journals (Sweden)

    Anne Grundy

    2017-01-01

    Full Text Available Introduction : Même si certaines études suggèrent une association entre le travail par quarts et l’obésité, peu sont fondées sur la population ou tiennent compte de divers horaires de travail par quarts. L’obésité étant associée à plusieurs problèmes de santé chroniques, il est important de comprendre quelles formes de travail par quarts ont une incidence sur elle et d’effectuer des travaux permettant d’évaluer de façon plus détaillée l’exposition au travail par quarts. Méthodologie : Au moyen d’une régression logistique polytomique multivariée, nous avons étudié l’association entre le travail par quarts (de soir ou nuit, par quarts ou autre type de rotation et le surpoids et l’obésité, en fonction d’une mesure transversale de l’indice de masse corporelle chez 1 561 hommes. Ces hommes avaient déjà servi de témoins dans une étude cas-témoins sur le cancer de la prostate menée dans le nord-est de l’Ontario de 1995 à 1999. Nous avons obtenu l’information sur leurs antécédents de travail (notamment sur le travail par quarts, leur taille et leur poids à partir de données autodéclarées recueillies par questionnaire. Résultats : Nous avons observé une association entre le fait d’avoir déjà travaillé par quarts (par opposition au fait de n’avoir jamais travaillé par quarts et le surpoids (RC [rapport de cotes] = 1,34; IC [intervalle de confiance] à 95 % : 1,05 à 1,73 ainsi que l’obésité (RC = 1,57; IC à 95 % : 1,12 à 2,21. Nous avons également observé des associations statistiquement non significatives avec le fait d’avoir déjà travaillé (par opposition au fait de n’avoir jamais travaillé de façon permanente selon un quart de soir ou de nuit. Nous avons par ailleurs observé une tendance à la hausse statistiquement significative en ce qui concerne le risque de surpoids et d’obésité en fonction de la durée du travail par quarts. Conclusion : Tant l

  4. Evolution de la gonadotropine plasmatique t-GtH après synchronization des ovulations par injection de 17α hydroxy-20β dihydroprogesterone chez la truite arc-en-ciel (Salmo gairdneri R.) : Evolution of plasmatic gonadotropin t-gth after synchronization of ovulations by injection of 17-α hydroxy-20β dihydroprogesterone in rainbow-trout (Salmo gairdneri R.)

    OpenAIRE

    Jalabert, Bernard; Breton, Bernard; Bry, C.

    1980-01-01

    L'injection de 17α hydroxy-20 β dihydroprogestérone (3 mg/kg) à des femelles dont les ovocytes sont au stade de « vésicule germinative semi-périphérique » entraîne une chute du niveau de t-GtH, très hautement significative 24 h. après injection, qui résulte vraisemblablement d'une rétroaction négative sur la sécrétion hypophysaire. Par la suite, après ovulation, la t-GtH plasmatique s'élève davantage chez les femelles subissant la rétention des ovules (50 µg/ml environ) que chez les femelles ...

  5. Utilisation des sécrétions de myriapodes chez les lémurs et les sapajous : fonction curative ou signalisation sociale ? Fur-rubbing with millipedes in lemurs and capuchin monkeys: social function or zoopharmacognosy?

    Directory of Open Access Journals (Sweden)

    Bruno Simmen

    2011-10-01

    Full Text Available L’utilisation des myriapodes en friction sur le pelage et d’autres zones corporelles est documentée chez les primates en conditions naturelles, notamment à partir des observations récurrentes menées chez le genre Cebus. La typologie de ces comportements suggère différentes hypothèses, fonctionnelles (zoopharmacognosie, alimentaire, sociale ou non (sensorielle, auto-stimulation. Nous présentons des observations qualitatives comparées de l’utilisation non alimentaire de myriapodes diplopodes chez une forme hybride du genre Eulemur au Sud de Madagascar (occurrences en janvier 2005 et chez le sapajou Cebus apella en Guyane Française (occurrences en mars-avril 1996. L’application des sécrétions à benzoquinones sur une large partie du pelage chez Cebus contraste avec la friction exclusive de la zone périgénitale faisant suite au flairage du diplopode chez Eulemur qui manifeste en outre une réponse stéréotypée analogue au flehmen. Dans notre étude, l’imprégnation de fluides à forte intensité olfactive potentialiserait la signalisation de l’identité individuelle chez Eulemur alors que le "fur-rubbing" chez Cebus est compatible avec l’hypothèse commune d’une forme d’appropriation des défenses antiparasitaires de ces invertébrés. La sécrétion de ces défenses chimiques n’est pas automatiquement déclenchée par la manipulation des diplopodes. Le stress induit par les morsures légères (Eulemur et Cebus et l’arrachage des pattes sur plusieurs segments (Cebus augmente la probabilité de sécrétion, ce qui témoignerait d’un apprentissage d’autant plus efficace des conditions d’émission de ces fluides que l’usage est spécifique et très opportuniste.Body-rubbing with millipedes is repeatedly documented in primates living under natural conditions, mainly in capuchin monkeys (Cebus spp.. Various functional (zoopharmacognosy, ingestion, social and non-functional hypotheses (sensory, auto

  6. Contenu de la fréquence de l'E.E.G. en fonction de l'effort physique et mental chez des malades présentant une insuffisance cérébrovasculaire (Communication préliminaire)

    NARCIS (Netherlands)

    Troost, J.; Kamp, A.; Kamphuisen, A.H.C.; Storm van Leeuwen, W.

    Le contenu de la fréquence de l'E.E.G. en fonction de l'effort physique et mental chez des malades présentant une insuffisance cérébro-vasculaire (une communication préalable). La méthode consiste en une analyse spectrale digitale de l'E.E.G., qui est enregistré à l'aide d'un système

  7. Evaluation du traitement antirétroviral chez les femmes enceintes VIH-1 positif, sur la transmission de l'infection de la mère à l'enfant: cas du Centre Médical Saint Camille de Ouagadougou, au Burkina Faso

    Science.gov (United States)

    Soubeiga, Serge Theophile; Compaore, Rebecca; Djigma, Florencia; Zagre, Nicaise; Assengone, Elsa; Traore, Lassina; Diarra, Birama; Bisseye, Cyrille; Ouermi, Djeneba; Sagna, Tani; Karou, Simplice; Pietra, Virginio; Simpore, Jacques

    2015-01-01

    Introduction L'infection au VIH chez les nouveau-nés par leur mère peut être réduite grâce à des programmes de prévention de transmission mère-enfant du VIH (PTME). L'objectif dans cette étude était d’évaluer le traitement antirétroviral chez les femmes enceintes VIH-1 positif sur la transmission mère-enfant de l'infection au Centre Médical Saint Camille de Ouagadougou, Burkina Faso. Méthodes Des échantillons de spot de sang total ont été collectés chez 160 enfants âgés de 6 semaines, nés de mères VIH-1 positif et chez 40 enfants âgés de 2 à 13 mois provenant d'orphelinats et dont les mères étaient inconnues. Ces échantillons ont été testés avec le kit Abbott Real Time HIV-1 Qualitative. Un questionnaire a permis de connaitre les âges et les fonctions des femmes enceintes. Résultats Les femmes enceintes avaient un âge moyen global de 29,50±5,19 ans. Au total, 50,5% (101/200) ont été mises sous combinaison AZT/3TC/NVP et 29,5% (59/200) étaient sous prophylaxie (AZT/3TC). Le taux de transmission verticale du VIH-1 était de 0,0% (0/160) (p VIH-1 de la mère à l'enfant. De plus, le dépistage par PCR, des enfants orphelins infectés verticalement par le VIH, permet leur prise en charge thérapeutique précoce. PMID:26301003

  8. Piscines et plages chez Kundera

    DEFF Research Database (Denmark)

    Boisen, Jørn

    2007-01-01

    Swimming pools, stricto sensu, are a newcomer in the gallery of western topoï, linked as they are to 20th century consumer culture. For obvious reasons they have become a recognized cinematographic topos, but - more surprisingly - they have also made their way to novel. For instance you find a lo...... and nihilism in a mode that is much darker and more troubled than one would expect...

  9. Du mucilage chez les algues

    NARCIS (Netherlands)

    Wildeman, de É.

    1942-01-01

    En examinant en 1939 dans une note présentée à l’Académie des Sciences de Belgique une étude de M. Ronse, nous avons été amené à reprendre des considérations sur les mucilages des végétaux et en particulier sur ceux des algues (22; 31). Déjà en 1891, dans nos ”Observations algologiques“ nous avons

  10. Measurement of Caesium-137 in the Normal Person; Dosage du Cesium 137 chez un Sujet Normal; 0418 0417 041c 0414 ; Determinacion Cuantitativa del Cesio-137 en el Individuo Normal

    Energy Technology Data Exchange (ETDEWEB)

    Huycke, E. J.; Oberhausen, E. [United States Army Medical Research Unit, Europe, Landstuhl/Pfalz, Federal Republic of Germany (Germany)

    1964-11-15

    During the period June 1959 to October 1963 the Landstuhl whole-body counter has measured the caesium-137 content of more than 15 000 normal persons. The monthly averages of these measurements indicate a steady increase In the caesium-137 content since June 1962. This increase has become more rapid during the period June 1963 to October 1963. A further evaluation of the monthly averages since June 1962 indicates a mean biologic half-life of caesium-137 of 140 d for persons older than 22 yr. A comparison of the mean caesium-137 content of persons between 8 and 17 yr of age with those older than 22 appears to indicate that the biologic half-life of caesium-137 is shorter in the younger people. This is in agreement with earlier data from this counter concerning measurements of caesium-137 content between June 1959 and December 1960: these data showed a lower caesium-137 content in children than in adults. Another evaluation of recent data from this unit concerns the standard deviation (sigma) of the caesium-137 content in a large population. From this population the sigma of measured caesium/g body potassium values is 33%. This is more than twice the sigma of the body potassium content of this same population. By comparing a group of persons who have undergone several repeat assays over an extended period of time with the monthly means of the total population measured, it has been found that the large sigma of caesium-137 content cannot be caused solely by the varying diets of the population measured. (author) [French] Au cours de la periode allant de juin 1959 a octobre 1963, l'anthropogammametre de Landstuhl a ete utilise pour mesurer la charge corporelle de cesium 137 chez plus de 15 000 sujets normaux. D'apres les moyennes mensuelles de ces mesures, la charge corporelle de cesium 137 a augmente constamment depuis juin 1962. Cette augmentation s'est acceleree au cours de la periode allant de juin 1963 a octobre 1963. Une analyse plus poussee des moyennes mensuelles

  11. Synthesis, structure, and characterization of two new bismuth(III) selenite/tellurite nitrates: [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}](NO{sub 3}) and [Bi(TeO{sub 3})](NO{sub 3})

    Energy Technology Data Exchange (ETDEWEB)

    Meng, Chang-Yu; Wei, Ming-Fang [Department of Chemistry and Materials, Yulin Normal University,Yulin, Guangxi 537000 (China); Geng, Lei, E-mail: lgeng.cn@gmail.com [Department of Materials Science and Engineering, Huaibei Normal University, Huaibei, Anhui 235000 (China); Hu, Pei-Qing; Yu, Meng-Xia [Department of Chemistry and Materials, Yulin Normal University,Yulin, Guangxi 537000 (China); Cheng, Wen-Dan [State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002 (China)

    2016-07-15

    Two new bismuth(III) selenite/tellurite nitrates, [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}](NO{sub 3}) and [Bi(TeO{sub 3})](NO{sub 3}), have been synthesized by conventional facile hydrothermal method at middle temperature 200 °C and characterized by single-crystal X-ray diffraction, powder diffraction, UV–vis–NIR optical absorption spectrum, infrared spectrum and thermal analylsis. Both [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}](NO{sub 3}) and [Bi(TeO3)](NO3) crystallize in the monoclinic centronsymmetric space group P2{sub 1}/c with a=9.9403(4) Å, b=9.6857(4) Å, c=10.6864(5) Å, β=93.1150(10)° for [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}](NO{sub 3}) and a=8.1489(3) Å, b=9.0663(4) Å, c=7.4729(3) Å, β=114.899(2)° for Bi(TeO3)(NO3), respectively. The two compounds, whose structures are composed of three different asymmetric building units, exhibit two different types of structures. The structure of [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}](NO{sub 3}) features a three-dimensional (3D) bismuth(III) selenite cationic tunnel structure [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}] {sup 3}{sub ∞} with NO{sub 3}{sup −} anion group filling in the 1D tunnel along b axis. The structure of [Bi(TeO{sub 3})](NO{sub 3}) features 2D bismuth(III) tellurite [Bi(TeO{sub 3}){sub 2}]{sup 2}{sub ∞} layers separated by NO{sub 3}{sup −} anion groups. The results of optical diffuse-reflectance spectrum measurements and electronic structure calculations based on density functional theory methods show that the two compounds are wide band-gap semiconductors. - Graphical abstract: Two novel bismuth{sup III} selenite/tellurite nitrates [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}](NO{sub 3}) with 3D tunnel structure and [Bi(TeO{sub 3})](NO{sub 3}) with 2D layer structure have been firstly synthesized and characterized. Display Omitted - Highlights: • Two novel bismuth{sup III} nitrates [(Bi{sub 3}O{sub 2})(SeO{sub 3}){sub 2}](NO{sub 3}) and [Bi(TeO{sub 3})](NO{sub 3}) were firstly

  12. La prise en charge à long terme de l’asthme chez les enfants inuits et des Premières nations : un outil de transfert du savoir fondé sur les lignes directrices canadiennes pour l’asthme pédiatrique, conçu pour être utilisé par les professionnels de la santé de première ligne qui travaillent dans des communautés isolées

    Science.gov (United States)

    Kovesi, Tom; Giles, Brenda Louise; Pasterkamp, Hans

    L’asthme est un grave problème de santé pour les enfants inuits et des Premières nations. Chez les enfants de moins d’un an, il faut distinguer l’asthme de la bronchiolite virale, anormalement fréquente chez les enfants autochtones du Canada. Chez les enfants de moins de six ans, le diagnostic dépend de la présence de symptômes classiques, de l’absence de caractéristiques atypiques et de la consignation de la réponse au traitement, notamment la réponse rapide et transitoire aux bronchodilatateurs. Chez les enfants plus âgés, il faut, dans la mesure du possible, déterminer la présence d’une obstruction réversible des voies aériennes par spirométrie afin de confirmer le diagnostic, ainsi qu’évaluer et corriger les déclencheurs environnementaux. L’utilisation régulière de corticoïdes en aérosol est la principale mesure à prendre pour maintenir un bon contrôle de l’asthme chez les enfants asthmatiques. Les clients et leur famille devraient recevoir une formation sur l’asthme. Il faut réévaluer régulièrement le contrôle aux visites de suivi dans des centres de santé et rajuster le traitement à la dose la plus basse possible pour le maintien de ce contrôle.

  13. Blessures liées à une chute chez les aînés canadiens entre 2005 et 2013 : une analyse de l’Enquête sur la santé dans les collectivités canadiennes

    Directory of Open Access Journals (Sweden)

    M. T. Do

    2015-01-01

    Full Text Available Introduction: Nous décrivons l’épidémiologie et les tendances des blessures liées à une chute chez les aînés canadiens de 65 ans et plus selon le sexe et l’âge, ainsi que les circonstances et les conséquences de ces blessures. Méthodologie: Nous avons utilisé des données représentatives tirées des échantillons de 2005, de 2009-2010 et de 2013 de l’Enquête sur la santé dans les collectivités canadiennes afin de calculer le nombre et les taux de blessures liées à une chute pour chaque année d’enquête. Nous avons combiné, dans la mesure du possible, les données d’au moins deux échantillons afin d’estimer la proportion de blessures liées à une chute par type de blessure, partie du corps affectée, type d’activité et type de traitement. Résultats: Le taux de blessures liées à une chute chez les aînés est passé de 49,4 à 58,8 pour 1 000 personnes entre 2005 et 2013, période durant laquelle le nombre de blessures liées à une chute a de façon générale augmenté de 54 %. Les femmes ont présenté des taux plus élevés que les hommes pour toutes les années d’enquête, ces taux augmentant avec l’âge. La tendance à la hausse dans les taux de blessures liées à une chute était plus marquée chez les femmes et les plus jeunes. Les cassures et les fractures (37 % ont été les blessures les plus courantes, et l’épaule et le bras (16 % ont été les parties du corps les plus couramment affectées. Plusieurs blessures liées à une chute se sont produites alors que la personne marchait sur une surface non enneigée ou glacée (45 %. Plus de 70 % des aînés qui ont cherché à obtenir des soins médicaux pour leur blessure se sont rendus au service d’urgence d’un hôpital. Conclusion: Compte tenu de l’augmentation du nombre et des taux de blessures liées à une chute au fil du temps, la surveillance des tendances et des profils de ces dernières demeure nécessaire.

  14. Consommation d’alcool et lignes directrices pour la consommation d’alcool à faible risque chez les adultes : une analyse transversale de l’Alberta’s Tomorrow Project

    Directory of Open Access Journals (Sweden)

    Darren R. Brenner

    2017-01-01

    Full Text Available Introduction : La consommation modérée ou élevée d’alcool constitue un facteur de risque de mortalité toutes causes confondues et de cancer. Nous disposons de données transversales grâce aux enquêtes nationales, mais jusqu'à présent aucunes données sur la consommation d’alcool en Alberta n'étaient disponibles pour une grande cohorte prospective. Notre objectif est de définir, à la lumière des lignes directrices de prévention du cancer, les niveaux de consommation d’alcool des adultes ayant pris part à l’Alberta’s Tomorrow Project. Nous avons également analysé les liens entre la consommation d’alcool et certains autres comportements à risque, en particulier à risque élevé. Méthodologie : Entre 2001 et 2009, 31 072 hommes et femmes de 35 à 69 ans ont participé à l’Alberta’s Tomorrow Project, une grande étude de cohorte provinciale. Des données concernant la consommation d’alcool dans les 12 derniers mois ont été obtenues pour 26 842 participants ayant répondu à des questionnaires autoadministrés sur la santé et sur le mode de vie. Nous avons effectué des analyses transversales sur la consommation d’alcool quotidienne et les lignes directrices de prévention du cancer en matière de consommation d’alcool en lien avec des facteurs sociodémographiques. Nous avons aussi examiné la prévalence combinée de la consommation d’alcool, du tabagisme, de l’obésité et de diverses comorbidités. Résultats : Environ 14 % des hommes et 12 % des femmes ont déclaré consommer davantage d’alcool que ce que préconisent les recommandations en matière de prévention du cancer. Une consommation plus importante d’alcool a été rapportée chez les plus jeunes, les citadins, les personnes à revenu plus élevé et celles consommant davantage de viande rouge. En outre, le volume de consommation quotidienne d’alcool était positivement associé au tabagisme, tant chez les hommes que chez les femmes

  15. Composition en acide alphalinolénique des esters de cholestérol plasmatiques : un marqueur de consommation chez l’homme

    Directory of Open Access Journals (Sweden)

    Combe Nicole

    2002-07-01

    étude cas-témoins de Simon et al. [10] a montré en 1995 qu’un taux plasmatique de 18:3n-3 élevé était associé à une réduction de 37% du risque d’accident vasculaire cérébral. Après analyse multivariée pour prendre en compte les facteurs de confusion, susceptibles d’interférer dans le risque étudié, seul le pourcentage de 18:3n-3 dans les EC plasmatiques restait inversement associé au risque d’accident vasculaire cérébral (p < 0,05. De même, l’étude d’intervention de Bemelmans et al. [13], destinée à la prévention MCV chez des sujets à risques, a récemment montré que le pourcentage de 18:3n-3 dans les EC du plasma était inversement associé à la pression diastolique (p < 0,05. Il ressort de l’ensemble de ces données que le niveau d’acide alphalinolénique souhaitable dans les EC du plasma se situerait entre 0,4 et 0,9% par rapport aux acides gras totaux liés au cholestérol.

  16. The Enhanced Radiocaesium Levels of People in Northern Sweden; Charge Corporelle de Radiocesium Relativement Elevie chez les Habitants de la Suede Septentrionale; 041f 041e 0414 0 ; Cargas de Radiocesio Anormalmente Elevadas en los Habitantes del Norte de Suecia

    Energy Technology Data Exchange (ETDEWEB)

    Liden, K.; Naversten, Y. [Radiation Physics Department, University of Lund (Sweden)

    1964-11-15

    After the discovery of the high caesium-137 body activity of Swedish Lapps early in 1961 measurements were performed on large groups of Lapps and other Swedes on a similar diet. In September, 1961 162 persons from an area close to the arctic circle were measured in a semi-portable whole-body counter. In the Lapp group caesium-137 levels ranging from 15 to 690 nc were found. At the same place a group of 157 persons were counted in April, 1962. At that time the caesium-137 range was 30 to 740 nc. During a five weeks expedition to seven different centres in northern Sweden in April, 1963 a total number of 458 persons were studied by means of the same counter set up in a bus. The caesium-137 range for Lapps in the above mentioned area was then 50 to 900 nc. The average caesium-137 body activity of all the adult male reindeer breeders (78 persons) measured in April, 1963 was 461 nc. The maximum body activity found was 1340 nc caesium-137. Details are presented on the variation of caesium-137 in human beings with age, sex, occupation and diet as well as on the seasonal and geographical variations found. An increase in the average caesium-137 body activity has been observed from 1961 to 1963. For comparison, non-Lapps have also been counted. Almost all of them also show a substantially enhanced caesium-137 level if compared with persons in southern Sweden. The radiation dose from caesium-137 is in many cases two to three times as large as the potassium-40 dose, the observed maximum giving a dose eight times that of the potassium dose. (author) [French] Lorsqu'on eut decouvert au debut de 1961 que la charge corporelle de cesium 137 etait elevee chez les Lapons de Suede, on a fait des dosages sur des groupes importants de Lapons et d'autres habitants de la Suede qui suivent un regime alimentaire analogue. En septembre 1961, on a effectue des dosages sur 162 personnes d'une region situee a proximite du cercle arctique au moyen d'un anthropogammametre semi- portatif. Chez les

  17. Profil épidémiologique et prise en charge des exacerbations d'asthme chez l'enfant à l'hôpital d'enfants de Rabat au Maroc

    Science.gov (United States)

    Boubkraoui, Mohamed El Mahdi; Benbrahim, Fadoua; Assermouh, Abdellah; El Hafidi, Naima; Benchekroun, Soumia; Mahraoui, Chafiq

    2015-01-01

    Introduction L'exacerbation d'asthme est un phénomène paroxystique qui peut mettre en jeu le pronostic vital. Le but de l’étude est d’évaluer le profil épidémiologique et les modalités de prise en charge de l'exacerbation d'asthme chez les enfants âgés de 2 à 15 ans dans l'unité de pneumoallergologie pédiatrique de l'hôpital d'enfants de Rabat au Maroc. Méthodes Il s'agit d'une étude rétrospective qui a concerné 1461 enfants hospitalisés pour exacerbation d'asthme modérée à sévère durant une période d'un an allant de décembre 2011 à novembre 2012, les exacerbations légères étant traitées en ambulatoire. Résultats Les hospitalisations pour exacerbation d'asthme chez les enfants ont représenté 34% de l'ensemble des hospitalisations avec trois pics en mai, septembre et décembre. L’âge moyen de survenue était de 3 ans et demi avec une prédominance masculine nette. L'exacerbation d'asthme était inaugurale dans 22% des cas. Les infections respiratoires virales dominaient les facteurs déclenchants des exacerbations d'asthme. Le séjour hospitalier était en moyenne de 3 jours. Un transfert en réanimation a été nécessaire dans 2% des cas. L’évolution sous traitement a toujours été favorable et la mortalité a été nulle. Conclusion La prévalence des hospitalisations pour exacerbation d'asthme suit un profil saisonnier lié aux effets environnementaux. La plupart de ces hospitalisations pourraient cependant être évitées grâce à un meilleur contrôle de l'asthme et à l'amélioration de l’éducation thérapeutique de l'enfant asthmatique et de son entourage. PMID:26090031

  18. Etude de l'anémie chez les enfants séropositifs au VIH naïfs au traitement antirétroviral à Lubumbashi, République Démocratique du Congo

    Science.gov (United States)

    Mwadianvita, Costa Kazadi; Ilunga, Eric Kasamba; Djouma, Jackson; Wembonyama, Cecile Watu; Mutomb, Florence Mujing A; Ekwalanga, Michel Balaka; Kabongo, Joe; Mundongo, Henri; Mupoya, Kalombo; Wembonyama, Stanis; Kalenga Mwenze, Prosper; Nkoy, Albert Mwembo-Tambwe A

    2014-01-01

    Introduction Beaucoup d'enfants infectés par le VIH arrivent à la consultation dans un état d'anémie. Notre objectif était d’évaluer la prévalence et le typage de l'anémie chez ces enfants. Méthodes C'est une étude transversale réalisée dans 3 centres de prise en charge des Personnes Vivant avec le VIH à Lubumbashi de Mai 2010 à Mai 2011. La population d’étude était de 152 enfants, âgés de 6 à 180 mois, naïfs au traitement antirétroviral. Les statistiques descriptives usuelles ont été utilisées. Résultats La prévalence globale de l'anémie (définie comme l'hémoglobine < 11g/dl) était de 69,1% (n=105) et 11,4% avaient une anémie sévère (Hg < 7,0 g/dl). Parmi eux, 16% ont été transfusés au moins 1 fois. L'anémie sévère était positivement associée au stade clinique de la maladie (p=0,02). L'anémie microcytaire était majoritaire dans les deux tranches d’âge. Elle était plus hypochrome chez les enfants en âge préscolaire soit 9,5% et plus normochrome en âge scolaire soit 15,2%. L'anémie normocytaire était plus normochrome dans les deux tranches d’âge soit 12,4% en âge préscolaire et 6,7% en âge scolaire. L'anémie macrocytaire était rare. Conclusion Environ sept enfants sur dix, âgés de moins de 15 ans infectés par le VIH naïfs au traitement antirétroviral dans notre milieu sont anémiques. L'anémie est corrélée à la sévérité de la maladie. Il est important d'associer une prise en charge nutritionnelle et corriger l'anémie avant une trithérapie antirétrovirale. PMID:25018796

  19. On the cholesterol transfer rates in the rat. The search for a slow component (1961); Sur les vitesses de transfert du cholesterol chez le rat. Recherche d'une composante lente (1961)

    Energy Technology Data Exchange (ETDEWEB)

    Chevallier, F [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1961-07-01

    The ingestion of cholesterol 4-{sup 14}C during 7, 27 and 43 weeks enables one to find that the size of the cholesterol transfer space in rats is not modified by the duration of the experiment. In male rats, the results obtained confirm on the one hand that 50 to 60 per cent of the total cholesterol of the animal is renewed by transfer, and on the other hand that 40 to 60 per cent of the cholesterol of the rat is inert as regards this process. In female rats, the size of the transfer space is 10 per cent larger than in the males, but the general conclusions are the same. (author) [French] L'ingestion de cholesterol 4-{sup 14}C durant 7, 27 et 43 semaines permet de constater que la grandeur de l'espace de transfert du cholesterol chez les rats n'est pas modifie par la duree de l'experience. Pour les rats males, les resultats, d'une part, confirment que 50 a 60 pour cent du cholesterol total de l'animal est renouvele par transfert, et d'autre part, que 40 a 50 pour cent du cholesterol du rat est inerte en regard de ce processus. Pour les rats femelles, la grandeur de l'espace de transfert est superieure de 10 pour cent a celle de l'espace de transfert des males, mais les conclusions d'ensemble restent les memes. (auteur)

  20. L’utilisation du prémélange de monensin chez les vaches laitières : un suivi simple et essentiel pour s’assurer d’une utilisation adéquate

    Science.gov (United States)

    Dubuc, Jocelyn; Baril, Jean; DesCôteaux, Luc

    2009-01-01

    Le prémélange de monensin est utilisé fréquemment sur les fermes laitières canadiennes. L’ingrédient actif de ce produit est le monensin sodique. Bien que son utilisation chez les vaches laitières soit sécuritaire, des cas de surdose ont été rapportés à la suite de consommation de niveaux de monensin plus élevés que ceux recommandés. Un suivi hebdomadaire du pourcentage de matières grasses du réservoir de lait de la ferme devrait être fait de routine suite à la livraison d’aliment médicamenteux contenant du monensin pour détecter rapidement les situations de surdose. L’observation d’une baisse soudaine de la consommation volontaire de matière sèche et l’apparition de diarrhée dans un troupeau sont d’autres signes cliniques de surdose de monensin. Une détection rapide de ces cas permettra de corriger la situation. PMID:19721781