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Sample records for chez rhodobacter sphaeroides

  1. Osmoregulation in Rhodobacter sphaeroides.

    OpenAIRE

    Abee, T; Palmen, R; Hellingwerf, K J; Konings, W N

    1990-01-01

    Betaine (N,N,N-trimethylglycine) functioned most effectively as an osmoprotectant in osmotically stressed Rhodobacter sphaeroides cells during aerobic growth in the dark and during anaerobic growth in the light. The presence of the amino acids L-glutamate, L-alanine, or L-proline in the growth medium did not result in a significant increase in the growth rate at increased osmotic strengths. The addition of choline to the medium stimulated growth at increased osmolarities but only under aerobi...

  2. Osmoregulation in Rhodobacter sphaeroides.

    Science.gov (United States)

    Abee, T; Palmen, R; Hellingwerf, K J; Konings, W N

    1990-01-01

    Betaine (N,N,N-trimethylglycine) functioned most effectively as an osmoprotectant in osmotically stressed Rhodobacter sphaeroides cells during aerobic growth in the dark and during anaerobic growth in the light. The presence of the amino acids L-glutamate, L-alanine, or L-proline in the growth medium did not result in a significant increase in the growth rate at increased osmotic strengths. The addition of choline to the medium stimulated growth at increased osmolarities but only under aerobic conditions. Under these conditions choline was converted via an oxygen-dependent pathway to betaine, which was not further metabolized. The initial rates of choline uptake by cells grown in media with low and high osmolarities were measured over a wide range of concentrations (1.9 microM to 2.0 mM). Only one kinetically distinguishable choline transport system could be detected. Kt values of 2.4 and 3.0 microM and maximal rates of choline uptake (Vmax) of 5.4 and 4.2 nmol of choline/min.mg of protein were found in cells grown in the minimal medium without or with 0.3 M NaCl, respectively. Choline transport was not inhibited by a 25-fold excess of L-proline or betaine. Only one kinetically distinguishable betaine transport system was found in cells grown in the low-osmolarity minimal medium as well as in a high-osmolarity medium containing 0.3 M NaCl. In cells grown and assayed in the absence of NaCl, betaine transport occurred with a Kt of 15.1 microM and a Vmax of 3.2 nmol/min . mg of protein, whereas in cells that were grown and assayed in the presence of 0.3 M NaCl, the corresponding values were 18.2 microM and 9.2 nmol of betaine/min . mg of protein. This system was also able to transport L-proline, but with a lower affinity than that for betaine. The addition of choline of betaine to the growth medium did not result in the induction of additional transport systems. PMID:2294084

  3. 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.

  4. Scanning electrochemical microscopy of living cells. 3. Rhodobacter sphaeroides.

    Science.gov (United States)

    Cai, Chenxin; Liu, Biao; Mirkin, Michael V; Frank, Harry A; Rusling, James F

    2002-01-01

    The scanning electrochemical microscope (SECM) was used to probe the redox activity of individual purple bacteria (Rhodobacter sphaeroides). The approaches developed in our previous studies of mammalian cells were expanded to measure the rates and investigate the pathway of transmembrane charge transfer in bacteria. The two groups of redox mediators (i.e., hydrophilic and hydrophobic redox species) were used to shuttle the electrons between the SECM tip electrode in solution and the redox centers inside the cell. The analysis of the dependencies of the measured rate constant on formal potential and concentration of mediator species in solution yielded information about the permeability of the outer cell membrane to different ionic species and intracellular redox properties. The maps of redox reactivity of the cell surface were obtained with a micrometer or submicrometer spatial resolution. PMID:11795778

  5. Cloning, nucleotide sequence, and expression of the Rhodobacter sphaeroides Y thioredoxin gene.

    OpenAIRE

    Pille, S.; Chuat, J C; Breton, A M; Clément-Métral, J D; Galibert, F

    1990-01-01

    Synthetic oligodeoxynucleotide probes based on the known amino acid sequence of Rhodobacter sphaeroides Y thioredoxin were used to identify, clone, and sequence the structural gene. The amino acid sequence derived from the DNA sequence of the R. sphaeroides gene was identical to the known amino acid sequence of R. sphaeroides thioredoxin. An NcoI site was created by directed mutagenesis at the beginning of the thioredoxin gene, inducing in the encoded protein the replacement of serine in posi...

  6. Sequence, chromophore extraction and 3-D model of the photoactive yellow protein from Rhodobacter sphaeroides

    NARCIS (Netherlands)

    R. Kort; M.K. Philips-Jones; D.M.F. Aalten; A. Haker; S.M. Hoffer; K.J. Hellingwerf; W. Crielaard

    1998-01-01

    The photoactive yellow protein (pyp) gene has been isolated from Rhodobacter sphaeroides by probing with a homologous PCR-product. A sequence analysis shows that this pyp gene encodes a 124 AA protein with 48% identity to the three known PYPs. Downstream from pyp, a number of adjacent open reading f

  7. Feasibility of biohydrogen production from tofu wastewater with glutamine auxotrophic mutant of Rhodobacter sphaeroides

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, G.H.; Wang, L.; Kang, Z.H. [School of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Tongji University, 1239 Siping road, Shanghai 200092 (China)

    2010-12-15

    NH{sub 4}{sup +}, which is normally the integrant in organic wastewater, such as Tofu wastewater, is an inhibitor to hydrogen production by anoxygenic phototrophic bacterium. In order to release inhibition of NH{sub 4}{sup +} to biohydrogen generation by Rhodobacter sphaeroides, a glutamine auxotrophic mutant R. sphaeroides TJ-0803 was obtained by mutagenizing with ethyl methane sulfonate. The mutant could generate biohydrogen efficiently in the medium with high NH{sub 4}{sup +} concentration, because the inhibition of NH{sub 4}{sup +} to nitrogenase was released. Under suitable conditions, TJ-0803 could effectively produce biohydrogen from tofu wastewater, which commonly containing 50-60 mg L{sup -1} NH{sub 4}{sup +}, and the generation rate was increased by more than 100% compared with that from wild-type R. sphaeroides. (author)

  8. Gene co-expression network analysis in Rhodobacter capsulatus and application to comparative expression analysis of Rhodobacter sphaeroides

    Energy Technology Data Exchange (ETDEWEB)

    Pena-Castillo, Lourdes; Mercer, Ryan; Gurinovich, Anastasia; Callister, Stephen J.; Wright, Aaron T.; Westbye, Alexander; Beatty, J. T.; Lang, Andrew S.

    2014-08-28

    The genus Rhodobacter contains purple nonsulfur bacteria found mostly in freshwater environments. Representative strains of two Rhodobacter species, R. capsulatus and R. sphaeroides, have had their genomes fully sequenced and both have been the subject of transcriptional profiling studies. Gene co-expression networks can be used to identify modules of genes with similar expression profiles. Functional analysis of gene modules can then associate co-expressed genes with biological pathways, and network statistics can determine the degree of module preservation in related networks. In this paper, we constructed an R. capsulatus gene co-expression network, performed functional analysis of identified gene modules, and investigated preservation of these modules in R. capsulatus proteomics data and in R. sphaeroides transcriptomics data. Results: The analysis identified 40 gene co-expression modules in R. capsulatus. Investigation of the module gene contents and expression profiles revealed patterns that were validated based on previous studies supporting the biological relevance of these modules. We identified two R. capsulatus gene modules preserved in the protein abundance data. We also identified several gene modules preserved between both Rhodobacter species, which indicate that these cellular processes are conserved between the species and are candidates for functional information transfer between species. Many gene modules were non-preserved, providing insight into processes that differentiate the two species. In addition, using Local Network Similarity (LNS), a recently proposed metric for expression divergence, we assessed the expression conservation of between-species pairs of orthologs, and within-species gene-protein expression profiles. Conclusions: Our analyses provide new sources of information for functional annotation in R. capsulatus because uncharacterized genes in modules are now connected with groups of genes that constitute a joint functional

  9. Brominated lipids identify lipid binding sites on the surface of the reaction center from Rhodobacter sphaeroides.

    Science.gov (United States)

    Roszak, Aleksander W; Gardiner, Alastair T; Isaacs, Neil W; Cogdell, Richard J

    2007-03-20

    This study describes the use of brominated phospholipids to distinguish between lipid and detergent binding sites on the surface of a typical alpha-helical membrane protein. Reaction centers isolated from Rhodobacter sphaeroides were cocrystallized with added brominated phospholipids. X-ray structural analysis of these crystals has revealed the presence of two lipid binding sites from the characteristic strong X-ray scattering from the bromine atoms. These results demonstrate the usefulness of this approach to mapping lipid binding sites at the surface of membrane proteins.

  10. Effect of Photo-Oxidation on Energy Transfer in Light Harvesting Complex (LH2) from Rhodobacter Sphaeroides 601

    Institute of Scientific and Technical Information of China (English)

    LIU Kang-Jun; LIU Wei-Min; YAN Yong-Li; DONG Zhi-Wei; LIU Yuan; XU Chun-He; QIAN Shi-Xiong

    2006-01-01

    @@ We study the photo-oxidation of bacteriochlorophylls (BChls) in peripheral light harvesting complexes (LH2) from rhodobacter sphaeroides by using the steady absorption and the femtosecond pump-probe measurement, to realize the detailed dynamics of LH2 in the presence of photo-oxidation.

  11. Dimerization of core complexes as an efficient strategy for energy trapping in Rhodobacter sphaeroides.

    Science.gov (United States)

    Chenchiliyan, Manoop; Timpmann, Kõu; Jalviste, Erko; Adams, Peter G; Hunter, C Neil; Freiberg, Arvi

    2016-06-01

    In the purple phototrophic bacterium Rhodobacter sphaeroides, light harvesting LH2 complexes transfer absorbed solar energy to RC-LH1-PufX core complexes, which are mainly found in the dimeric state. Many other purple phototrophs have monomeric core complexes and the basis for requiring dimeric cores is not fully established, so we analysed strains of Rba. sphaeroides that contain either native dimeric core complexes or altered monomeric cores harbouring a deletion of the first 12 residues from the N-terminus of PufX, which retains the PufX polypeptide but removes the major determinant of core complex dimerization. Membranes were purified from strains with dimeric or monomeric cores, and with either high or low levels of the LH2 complex. Samples were interrogated with absorption, steady-state fluorescence, and picosecond time-resolved fluorescence kinetic spectroscopies to reveal their light-harvesting and energy trapping properties. We find that under saturating excitation light intensity the photosynthetic membranes containing LH2 and monomeric core complexes have fluorescence lifetimes nearly twice that of membranes with LH2 plus dimeric core complexes. This trend of increased lifetime is maintained with RCs in the open state as well, and for two different levels of LH2 content. Thus, energy trapping is more efficient when photosynthetic membranes of Rba. sphaeroides consist of RC-LH1-PufX dimers and LH2 complexes. PMID:27013332

  12. Transient dynamic phenotypes as criteria for model discrimination: fold-change detection in Rhodobacter sphaeroides chemotaxis.

    Science.gov (United States)

    Hamadeh, Abdullah; Ingalls, Brian; Sontag, Eduardo

    2013-03-01

    The chemotaxis pathway of the bacterium Rhodobacter sphaeroides shares many similarities with that of Escherichia coli. It exhibits robust adaptation and has several homologues of the latter's chemotaxis proteins. Recent theoretical results have correctly predicted that the E. coli output behaviour is unchanged under scaling of its ligand input signal; this property is known as fold-change detection (FCD). In the light of recent experimental results suggesting that R. sphaeroides may also show FCD, we present theoretical assumptions on the R. sphaeroides chemosensory dynamics that can be shown to yield FCD behaviour. Furthermore, it is shown that these assumptions make FCD a property of this system that is robust to structural and parametric variations in the chemotaxis pathway, in agreement with experimental results. We construct and examine models of the full chemotaxis pathway that satisfy these assumptions and reproduce experimental time-series data from earlier studies. We then propose experiments in which models satisfying our theoretical assumptions predict robust FCD behaviour where earlier models do not. In this way, we illustrate how transient dynamic phenotypes such as FCD can be used for the purposes of discriminating between models that reproduce the same experimental time-series data.

  13. Transient dynamic phenotypes as criteria for model discrimination: fold-change detection in Rhodobacter sphaeroides chemotaxis.

    Science.gov (United States)

    Hamadeh, Abdullah; Ingalls, Brian; Sontag, Eduardo

    2013-03-01

    The chemotaxis pathway of the bacterium Rhodobacter sphaeroides shares many similarities with that of Escherichia coli. It exhibits robust adaptation and has several homologues of the latter's chemotaxis proteins. Recent theoretical results have correctly predicted that the E. coli output behaviour is unchanged under scaling of its ligand input signal; this property is known as fold-change detection (FCD). In the light of recent experimental results suggesting that R. sphaeroides may also show FCD, we present theoretical assumptions on the R. sphaeroides chemosensory dynamics that can be shown to yield FCD behaviour. Furthermore, it is shown that these assumptions make FCD a property of this system that is robust to structural and parametric variations in the chemotaxis pathway, in agreement with experimental results. We construct and examine models of the full chemotaxis pathway that satisfy these assumptions and reproduce experimental time-series data from earlier studies. We then propose experiments in which models satisfying our theoretical assumptions predict robust FCD behaviour where earlier models do not. In this way, we illustrate how transient dynamic phenotypes such as FCD can be used for the purposes of discriminating between models that reproduce the same experimental time-series data. PMID:23293140

  14. Advancing Rhodobacter sphaeroides as a platform for expression of functional membrane proteins.

    Science.gov (United States)

    Erbakan, Mustafa; Curtis, Brandon S; Nixon, B Tracy; Kumar, Manish; Curtis, Wayne R

    2015-11-01

    Membrane protein overexpression is often hindered by toxic effects on the expression host, limiting achievable volumetric productivity. Moreover, protein structure and function may be impaired due to inclusion body formation and proteolytic degradation. To address these challenges, we employed the photosynthetic bacterium, Rhodobacter sphaeroides for expression of challenging membrane proteins including human aquaporin 9 (hAQP9), human tight junction protein occludin (Occ), Escherichia coli toxin peptide GhoT, cellulose synthase enzyme complex (BcsAB) of R. sphaeroides and cytochrome-cy (Cyt-cy) from Rhodobacter capsulatus. Titers of 47 mg/L for Cyt-cy, 7.5 mg/L for Occ, 1.5 mg/L for BcsAB and 0.5 mg/L for hAQP9 were achieved from affinity purification. While purification of GhoT was not successful, transformants displayed a distinct growth phenotype that correlated with GhoT expression. We also evaluated the functionality of these proteins by performing water transport studies for hAQP9, peroxidase activity for cytochrome-cy, and in vitro cellulose synthesis activity assay for BcsAB. While previous studies with Rhodobacter have utilized oxygen-limited semi-aerobic growth for membrane protein expression, substantial titer improvements are achieved as a result of a 3-fold increase in biomass yield using the anaerobic photoheterotrophic growth regime, which utilizes the strong native puc promoter. This versatile platform is shown to enable recovery of a wide variety of difficult-to-express membrane proteins in functional form.

  15. Excited-state dynamics in light-harvesting complex of Rhodobacter sphaeroides

    Institute of Scientific and Technical Information of China (English)

    LIU KangJun; LIU WeiMin; YAN YongLi; DONG ZhiWei; XU ChunHe; QIAN ShiXiong

    2008-01-01

    Photodynamics of peripheral antenna complexes, light-harvesting complex (LH2) of Rhodobacter (Rb) Sphaeroides 601, was studied using femtosecond pump-probe technique at different laser wavelengths. The obtained results reveal dramatic dynamical evolutions within B800 and B850 absorption bands of antenna complexes LH2. At excitation wavelength around 835 nm, a sharp photobleaching signal was observed which was assigned to the contribution of the two-exciton state, which was further confirmed by the power dependence measurement. Rate equations with eight-level scheme were used to calculate the population evolution in LH2 and the transient dynamics under femtosecond pulse excitation. The research results prove that not only the transition from ground state to one-exciton state but also that from one-exciton state to two-exciton state contribute to the photodynamics of B850.

  16. Influence of pigment substitution on the electrochemical properties of Rhodobacter sphaeroides 601 reaction centers

    Institute of Scientific and Technical Information of China (English)

    ZOU; YOnglong(

    2001-01-01

    [1]Deisenhofer. J., Epp, O.. Miki, K. et al., Structure of the protein subunits in the photosynthetic reaction center of Rhodopseudomonas viridis at 3A resolution, Nature, 1985, 318: 618-624.[2]Marcus, R. A., Election transfer reaction in chemistry: Theory and experiment (Nobel lecture), Angewandte Chemie, 1993,32: 1111-1121.[3]Woodbury, N. W., Becker, M., Middendorf, D. et al., Picosecond kinetics of the initial photochemical electron-transfer reaction in bacterial photosynthetic reaction centers, Biochemistry, 1985, 24 (26): 7516-7521.[4]Scheer, H., Struck, A., Bacterial reaction centers with modified tetrapyrrole chromophores, in The Photosynthetic Reaction Center (Ⅰ) (eds. Deisenhofer, J., Norris, J.), San Diego: Academic Press, 1993, 157-192.[5]Meyer, M., Scheer, H., Reaction centers of Rhodobacter sphaeroides R26 containing C-3 acetyl and vinyl (bacterio)pheophytines at sites HA,B, Photosynth. Res., 1995, 44: 55-65.[6]Schmidt, S., Arlt, T., Hamm, P. et al., Energetics of the primary electron transfer reaction revealed by ultrafast spectroscopy on modified bacterial reaction centers, Chem. Phys. Lett., 1994, 223: 116-120.[7]Kennis, J. T. M., Shkuropatov, A. Y., Van Stokkum, I. H. M. et al., Formation of a long-lived P+BA- state in plant pheophytin-exchanged reaction centers of Rhodobacter sphaeroides R26 at low temperature, Biochemistry, 1997, 36:16231-16238.[8]Tasayco, M. L., Carey, J., Ordered self-assembly of polypeptide fragments to form native like dimeric trp repressor, Science. 1992, 255: 594-597.[9]Kong, J. L., Lu, Z. Q., Lvov, Y. M. et al., Direct electrochemistry of cofactor redox sites in a bacterial photosynthetic reaction center protein, J. Am. Chem. Soc., 1998, 120 (29): 7371-7372.[10]Nassar, A. E. F., Bobbitt, J. M., Stuart, J. M. et al., Catalytic reduction of organohalide pollutants by myoglobin in a biomembrane-like surfactant film, J. Am. Chem. Soc., 1995, 117: 10986-10993.[11]Zeng, X. H., Wu, Y

  17. 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.

  18. 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

    2015-02-01

    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 CC 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 energy transfer dynamics of carotenoids in bacterial photosynthesis.

  19. Hydrogen gas production by combined systems of Rhodobacter sphaeroides O.U.001 and Halobacterium salinarum in a photobioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Zabut, Baker; El-Kahlout, Kamal [Department of Biochemistry, School of Science, IUG, Gaza (PS); Yuecel, Meral [Department of Biology, Middle East Technical University, 06531 Ankara (Turkey); Guenduez, Ufuk; Tuerker, Lemi [Department of Chemistry, Middle East Technical University, 06531 Ankara (Turkey); Eroglu, Inci [Department of Chemical Engineering, Middle East Technical University, 06531 Ankara (Turkey)

    2006-09-15

    Rhodobacter sphaeroides O.U.001 is a photosynthetic non-sulfur bacterium which produces hydrogen from organic compounds under anaerobic conditions. Halobacterium salinarum is an archaeon and lives under extremely halophilic conditions (4M NaCl). H. salinarum contains a retinal protein bacteriorhodopsin in its purple membrane which acts as a light-driven proton pump. In this study the Rhodobacter sphaeroides O.U.001 culture was combined with different amounts of packed cells of H. salinarum S9 or isolated purple membrane fragments in order to increase the photofermentative hydrogen gas production. The packed cells of H. salinarum have the ability to pump protons upon illumination due to the presence of bacteriorhodopsin. The proton gradient produced may be used for the formation of ATP or protons may be used for H{sub 2} production by R. sphaeroides. Similar to intact cells purple membrane fragments may also form vesicles around certain ions and may act like closed systems. The hydrogen production experiments were carried out using 400ml water-jacketed-glass column stirred photobioreactors. In combined systems 10-200nmol of bacteriorhodopsin was used. Hydrogen gas production was enhanced by four- to sixfold in combined systems of H. salinarum packed cells with R. sphaeroides O.U.001 cell. Stirring both increased the total gas produced and enhanced the rate of hydrogen production. The light energy conversion efficiency was increased from 0.6% to 2.25% in combined systems. (author)

  20. Energy transfer properties of Rhodobacter sphaeroides chromatophores during adaptation to low light intensity.

    Science.gov (United States)

    Driscoll, B; Lunceford, C; Lin, S; Woronowicz, K; Niederman, R A; Woodbury, N W

    2014-08-28

    Time-resolved fluorescence spectroscopy was used to explore the pathway and kinetics of energy transfer in photosynthetic membrane vesicles (chromatophores) isolated from Rhodobacter (Rba.) sphaeroides cells harvested 2, 4, 6 or 24 hours after a transition from growth in high to low level illumination. As previously observed, this light intensity transition initiates the remodeling of the photosynthetic apparatus and an increase in the number of light harvesting 2 (LH2) complexes relative to light harvesting 1 (LH1) and reaction center (RC) complexes. It has generally been thought that the increase in LH2 complexes served the purpose of increasing the overall energy transmission to the RC. However, fluorescence lifetime measurements and analysis in terms of energy transfer within LH2 and between LH2 and LH1 indicate that, during the remodeling time period measured, only a portion of the additional LH2 generated are well connected to LH1 and the reaction center. The majority of the additional LH2 fluorescence decays with a lifetime comparable to that of free, unconnected LH2 complexes. The presence of large LH2-only domains has been observed by atomic force microscopy in Rba. sphaeroides chromatophores (Bahatyrova et al., Nature, 2004, 430, 1058), providing structural support for the existence of pools of partially connected LH2 complexes. These LH2-only domains represent the light-responsive antenna complement formed after a switch in growth conditions from high to low illumination, while the remaining LH2 complexes occupy membrane regions containing mixtures of LH2 and LH1-RC core complexes. The current study utilized a multi-parameter approach to explore the fluorescence spectroscopic properties related to the remodeling process, shedding light on the structure-function relationship of the photosynthetic assembles. Possible reasons for the accumulation of these largely disconnected LH2-only pools are discussed. PMID:25008288

  1. 5-Aminolevulinate production by Escherichia coli containing the Rhodobacter sphaeroides hemA gene

    Energy Technology Data Exchange (ETDEWEB)

    Van Der Werf, M.J. [Michigan State Univ., East Lansing, MI (United States); Zeikus, J.G. [Michigan State Univ., East Lansing, MI (United States)]|[MBI International, Lansing, MI (United States)

    1996-10-01

    The Rhodobacter sphaeroides hemA gene codes for 5-aminolevulinate (ALA) synthase. This enzyme catalyzes the pyridoxal phosphate-dependent condensation of succinyl coenzyme A and glycine-forming ALA. The R. sphaeroides hemA gene in the pUC18/19 vector system was transformed into Escherichia coli. The effects of both genetic and physiological factors on the expression of ALA synthase and the production of ALA were studied. ALA synthase activity levels were maximal when hemA had the same transcription direction as the lac promoter. The distance between the lac promoter and hemA affected the expression of ALA synthase on different growth substrates. The E. coli host strain used had an enormous effect on the ALA synthase activity level and on the production of ALA, with E. coli DH1 being best suited. The ALA synthase activity level was also dependent on the carbon source. Succinate, L-malate, fumarate, and L-aspartate gave the highest levels of ALA synthase activity, while the use of lactose as a carbon source resulted in a repression of ALA synthase. After growth on succinate, ALA synthase represented {approx}5% of total cellular protein. The ALA synthase activity level was also dependent on the pH of the medium, with maximal activity occurring at pH 6.5. ALA production by whole cells was limited by the availability of glycine, and the addition of 2 g of glycine per liter to the growth medium increased the production of ALA fivefold, to 2.25 mM. In recombinant E. coli extracts, up to 22 mM ALA was produced from succinate, glycine, and ATP. 58 refs., 4 figs., 7 tabs.

  2. 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. PMID:25512104

  3. Acquirement and characterization of a carotenoid mutant (GM309) of Rhodobacter sphaeroides 601

    Institute of Scientific and Technical Information of China (English)

    LIU Yuan; ZHANG Wei; WU Yongqiang; XU Chunhe

    2004-01-01

    A green mutant was obtained among the chemically induced mutants of Rhodobacter sphaeroides 601 (RS601) and named GM309. A blue shift of 20 nm of the carotenoid absorption spectrum was found in the light-harvesting complex II (LH2) of GM309. Different from LH2 of RS601, it was found that the carotenoids in GM309-LH2 changed to be neurosporene by mutation. Neurosporene lacks a conjugate double bond, compared with the spheroidene in RS601-LH2 which has ten conjugate double bonds. As shown by absorption and circular dichroism spectroscopy, the overall structure of GM309-LH2 is little affected by this change. From fluorescence emission spectra, it is found that GM309-LH2 can transfer energy from carotenoids to Bchl-B850 without any change in efficiency. But the efficiency of energy transfer from B800 to B850 in GM309-LH2 is decreased to be 42% of that of the native. This work would provide a novel method to investigate the mechanism of excitation energy transfer in LH2.

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

    International Nuclear Information System (INIS)

    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)

  5. In vitro assessment of gastrointestinal viability of two photosynthetic bacteria, Rhodopseudomonas palustris and Rhodobacter sphaeroides

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The objectives of this study were to assess the potential of two photosynthetic bacteria (PSB), Rhodopseudomonas palustris HZ0301 and Rhodobacter sphaeroides HZ0302, as probiotics in aquaculture. The viability of HZ0301 and HZ0302 in simulated gastric transit conditions (pH 2.0, pH 3.0 and pH 4.0 gastric juices) and in simulated small intestinal transit conditions (pH 8.0, with or without 0.3% bile salts) was tested. The effects of HZ0301 and HZ0302 on the viability and permeability of intestinal epithelial cell in primary culture of tilapias, Oreochromis nilotica, were also detected. All the treatments were determined with three replicates. The simulated gastric transit tolerance of HZ0301 and HZ0302 strains was pH-dependent and correspondingly showed lower viability at pH 2.0 after 180 min compared with pH 3.0 and pH 4.0. Both HZ0301 and HZ0302 were tolerant to simulated small intestine transit with or without bile salts in our research. Moreover, there was no significant difference (P>0.05) among three treatments including the control and the groups treated with HZ0301 or HZ0302 both in intestinal epithelial cell viability and membrane permeability, showing no cell damage. In summary, this study demonstrated that HZ0301 and HZ0302 had high capacity of upper gastrointestinal transit tolerance and were relatively safe for intestinal epithelial cells of tilapias.

  6. Native Mass Spectrometry Characterizes the Photosynthetic Reaction Center Complex from the Purple Bacterium Rhodobacter sphaeroides

    Science.gov (United States)

    Zhang, Hao; Harrington, Lucas B.; Lu, Yue; Prado, Mindy; Saer, Rafael; Rempel, Don; Blankenship, Robert E.; Gross, Michael L.

    2016-08-01

    Native mass spectrometry (MS) is an emerging approach to study protein complexes in their near-native states and to elucidate their stoichiometry and topology. Here, we report a native MS study of the membrane-embedded reaction center (RC) protein complex from the purple photosynthetic bacterium Rhodobacter sphaeroides. The membrane-embedded RC protein complex is stabilized by detergent micelles in aqueous solution, directly introduced into a mass spectrometer by nano-electrospray (nESI), and freed of detergents and dissociated in the gas phase by collisional activation. As the collision energy is increased, the chlorophyll pigments are gradually released from the RC complex, suggesting that native MS introduces a near-native structure that continues to bind pigments. Two bacteriochlorophyll a pigments remain tightly bound to the RC protein at the highest collision energy. The order of pigment release and their resistance to release by gas-phase activation indicates the strength of pigment interaction in the RC complex. This investigation sets the stage for future native MS studies of membrane-embedded photosynthetic pigment-protein and related complexes.

  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. Brewery wastewaters in photobiological hydrogen generation in presence of Rhodobacter sphaeroides O.U. 001

    Energy Technology Data Exchange (ETDEWEB)

    Seifert, K.; Waligorska, M.; Laniecki, M. [Faculty of Chemistry, A. Mickiewicz University, Grunwaldzka 6, 60-780 Poznan (Poland)

    2010-05-15

    Rhodobacter sphaeroides O.U. 001 (concentration of inoculum-0.36 g dry wt/l) and brewery wastewaters were applied in photobiogeneration of hydrogen under illumination of 116 W/m{sup 2}. The best results were obtained with filtered wastewaters sterilized at 120 C for 20 min and maximal concentration of waste in medium equal 10% v/v. The main product in generated biogas was hydrogen (90%). After sterilization the amount of generated hydrogen was tripled (from 0.76 to 2.2 l H{sub 2}/l medium), whereas waste concentration of 10% v/v resulted in the best substrate yield (0.22 l H{sub 2}/l of waste). Under these conditions the amount of generated hydrogen was 2.24 l H{sub 2}/l medium and light conversion efficiency reached value of 1.7%. The modified Gompertz equations served in modeling of the kinetics of the studied process. (author)

  9. Modification of galactitol dehydrogenase from Rhodobacter sphaeroides D for immobilization on polycrystalline gold surfaces.

    Science.gov (United States)

    Kornberger, P; Gajdzik, J; Natter, H; Wenz, G; Giffhorn, F; Kohring, G W; Hempelmann, R

    2009-10-20

    Galactitol dehydrogenase (GatDH) from Rhodobacter sphaeroides is a multifunctional enzyme that catalyzes in the presence of oxidized beta-nicotinamide adenine dinucleotide (NAD(+)) the interconversion of various multivalent aliphatic alcohols to the corresponding ketones. The recombinant GatDH was provided with an N-terminal His(6)-tag to which distally up to three cysteine residues were attached. This protein construct maintained nearly full enzymatic activity, and it could be covalently immobilized via thiol bonds onto the surface of a gold electrode. Binding of GatDH onto the gold electrode was verified by SPR measurements, and residual enzyme activity was measured by cyclic voltammetry using 1,2-hexanediol as substrate, the cofactor NAD(+) and the redox mediator CTFM (4-carboxy-2,5,7-trinitrofluorenyliden-malonnitrile) in solute form. The results demonstrate the possibility of a directed functional immobilization of proteins on gold surfaces, which represents a proof-of-concept for the development of reactors for electrochemical synthon preparation using dehydrogenases.

  10. 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.

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

    International Nuclear Information System (INIS)

    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.

  12. The Extract of Rhodobacter sphaeroides Inhibits Melanogenesis through the MEK/ERK Signaling Pathway

    Directory of Open Access Journals (Sweden)

    Chen-Hsun Liu

    2013-06-01

    Full Text Available Reducing hyperpigmentation has been a big issue for years. Even though pigmentation is a normal mechanism protecting skin from UV-causing DNA damage and oxidative stress, it is still an aesthetic problem for many people. Bacteria can produce some compounds in response to their environment. These compounds are widely used in cosmetic and pharmaceutical applications. Some probiotics have immunomodulatory activities and modulate the symptoms of several diseases. Previously, we found that the extracts of Rhodobacter sphaeroides (Lycogen™ inhibited nitric oxide production and inducible nitric-oxide synthase expression in activated macrophages. In this study, we sought to investigate an anti-melanogenic signaling pathway in α-melanocyte stimulating hormone (α-MSH-treated B16F10 melanoma cells and zebrafish. Treatment with Lycogen™ inhibited the cellular melanin contents and expression of melanogenesis-related protein, including microphthalmia-associated transcription factor (MITF and tyrosinase in B16F10 cells. Moreover, Lycogen™ reduced phosphorylation of MEK/ERK without affecting phosphorylation of p38. Meanwhile, Lycogen™ decreased zebrafish melanin expression in a dose-dependent manner. These findings establish Lycogen™ as a new target in melanogenesis and suggest a mechanism of action through the ERK signaling pathway. Our results suggested that Lycogen™ may have potential cosmetic usage in the future.

  13. Physiological roles for two periplasmic nitrate reductases in Rhodobacter sphaeroides 2.4.3 (ATCC 17025).

    Science.gov (United States)

    Hartsock, Angela; Shapleigh, James P

    2011-12-01

    The metabolically versatile purple bacterium Rhodobacter sphaeroides 2.4.3 is a denitrifier whose genome contains two periplasmic nitrate reductase-encoding gene clusters. This work demonstrates nonredundant physiological roles for these two enzymes. One cluster is expressed aerobically and repressed under low oxygen while the second is maximally expressed under low oxygen. Insertional inactivation of the aerobically expressed nitrate reductase eliminated aerobic nitrate reduction, but cells of this strain could still respire nitrate anaerobically. In contrast, when the anaerobic nitrate reductase was absent, aerobic nitrate reduction was detectable, but anaerobic nitrate reduction was impaired. The aerobic nitrate reductase was expressed but not utilized in liquid culture but was utilized during growth on solid medium. Growth on a variety of carbon sources, with the exception of malate, the most oxidized substrate used, resulted in nitrite production on solid medium. This is consistent with a role for the aerobic nitrate reductase in redox homeostasis. These results show that one of the nitrate reductases is specific for respiration and denitrification while the other likely plays a role in redox homeostasis during aerobic growth. PMID:21949073

  14. Amelioration of dextran sodium sulfate-induced colitis in mice by Rhodobacter sphaeroides extract.

    Science.gov (United States)

    Liu, Wen-Sheng; Chen, Man-Chin; Chiu, Kuo-Hsun; Wen, Zhi-Hong; Lee, Che-Hsin

    2012-01-01

    Bacteria can produce some compounds in response to their environment. These compounds are widely used in cosmetic and pharmaceutical applications. Some probiotics have immunomodulatory activities and modulate the symptoms of several diseases. Autoimmune diseases represent a complex group of conditions that are thought to be mediated through the development of autoreactive immunoresponses. Inflammatory bowel disease (IBD) is common autoimmune disease that affects many individuals worldwide. Previously, we found that the extracts of Rhodobacter sphaeroides (Lycogen) inhibited nitric oxide production and inducible nitric-oxide synthase expression in activated macrophages. In this study, the effect of Lycogen, a potent anti-inflammatory agent, was evaluated in mice with dextran sodium sulfate (DSS)-induced colitis. Oral administration of Lycogen reduced the expressions of proinflammatory cytokines (tumor necrosis factor-α and interleukin-1β) in female BABL/c mice. In addition, the increased number of bacterial flora in the colon induced by DSS was amelirated by Lycogen. The histological score of intestinal inflammation in 5% DSS-treated mice after oral administration of Lycogen was lower than that of control mice. Meanwhile, Lycogen dramatically prolonged the survival of mice with severe colitis. These findings identified that Lycogen is an anti-inflammatory agent with the capacity to ameliorate DSS-induced colitis. PMID:23159923

  15. Influence of pigment substitution on the electrochemical properties of Rhodobacter sphaeroides 601 reaction centers

    Institute of Scientific and Technical Information of China (English)

    邹永龙; 赵杰权; 陈志龙; 孔继烈; 曾小华; 徐春和

    2001-01-01

    With the help of pigment substitution, self-assembled monolayer film and square wave voltammetry, the influence of pigment substitution on the electrochemical properties of Rhodobacter sphaeroides 601 reaction centers was investigated. Results showed that the charge separation could also be driven by externally electric field, similar to the primary photochemical reaction in purple bacterial reaction center. On the surface of Au electrode, a self-assembled monolayer film (the RC-PDDA-DMSA film) was made up of 2,3-dimercaptosuccinic acid (DMSA), poly-dimeth-yldiallylammonium chloride (PDDA) and reaction center (RC). When square wave voltammetry was used to study the RC-PDDA-DMSA film, four redox pairs in the photochemical reaction of RC were observed by changing frequency. With nonlinear fitting, the standard potential of P/P+ and the corresponding electrode reaction rate constant were determined to be 0.522 V and 13.04 S-1, respectively. It was found that the redox peak at -0.02 V changed greatly when bacteriopheophytin was substituted by plant pheophytin in the reaction center. Further studies indicated that this change resulted from the decrease in electron transfer rate between Bphe-/Bphe (Phe-/Phe) and QA-/QA after pigment substitution. After investigations of spectra and electrochemical properties of different RCs and comparisons of different function groups of pigments, it was indicated that the phytyl tail, similar to other substituted groups of pheophytin, affected the efficiencies of pigment substitution.

  16. Replacement of bacteriopheophytin in reaction centers from Rhodobacter sphaeroides RS601 with plant pheophytin

    Institute of Scientific and Technical Information of China (English)

    曾小华; 吴永强; 沈允钢; 徐春和

    2000-01-01

    In the presence of acetone and an excess of exogenous plant pheophytins, bacterio-pheophytins in the reaction centers from Rhodobacter sphaeroides RS601 were replaced by pheophytins at sites HA and HB, when incubated at 43.5℃ for more than 15 min. The substitution of bacteriopheophytins in the reaction centers was 50% and 71% with incubation of 15 and 60 min, respectively. In the absorption spectra of pheophytin-replaced reaction centers (Phe RCs), bands assigned to the transition moments Qx (537 nm) and QY (758 nm) of bacteriopheophytin disappeared, and three distinct bands assigned to the transition moments Qx (509/542 nm) and QY (674 nm) of pheophytin appeared instead. Compared to that of the control reaction centers, the photochemical activities of Phe RCs are 78% and 71% of control, with the incubation time of 15 and 60 min. Differences might exist between the redox properties of Phe RC and of native reaction centers, but the substitution is significant, and the new system is available for further

  17. Characterization of genes encoding dimethyl sulfoxide reductase of Rhodobacter sphaeroides 2.4.1T: an essential metabolic gene function encoded on chromosome II.

    OpenAIRE

    Mouncey, N J; Choudhary, M.; Kaplan, S.

    1997-01-01

    Rhodobacter sphaeroides 2.4.1T is a purple nonsulfur facultative phototrophic bacterium which exhibits remarkable metabolic diversity as well as genomic complexity. Under anoxic conditions, in the absence of light and the presence of dimethyl sulfoxide (DMSO) or trimethylamine N-oxide (TMAO), R. sphaeroides 2.4.1T utilizes DMSO or TMAO as the terminal electron acceptor for anaerobic respiration, which is mediated by the molybdoenzyme DMSO reductase. Sequencing of a 13-kb region of chromosome ...

  18. Insights into the species-specific TLR4 signaling mechanism in response to Rhodobacter sphaeroides lipid A detection

    OpenAIRE

    Anwar, Muhammad Ayaz; Panneerselvam, Suresh; Shah, Masaud; Choi, Sangdun

    2015-01-01

    TLR4 in complex with MD2 senses the presence of lipid A (LA) and initiates a signaling cascade that curb the infection. This complex is evolutionarily conserved and can initiate the immune system in response to a variety of LAs. In this study, molecular dynamics simulation (25 ns) was performed to elucidate the differential behavior of TLR4/MD2 complex in response to Rhodobacter sphaeroides lipid A (RsLA). Penta-acyl chain-containing RsLA is at the verge of agonist (6 acyl-chains) and antagon...

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

    Energy Technology Data Exchange (ETDEWEB)

    Heintz, Udo; Meinhart, Anton; Winkler, Andreas, E-mail: andreas.winkler@mpimf-heidelberg.mpg.de [Max Planck Institute for Medical Research, Heidelberg (Germany)

    2014-03-01

    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{sub Q-PAS1}) and two (PpsR{sub N-Q-PAS1}) PAS domains, respectively, are presented and the multi-step strategy required for the phasing of a triple PAS domain construct (PpsR{sub ΔHTH}) is illustrated. While parts of the biologically relevant dimerization interface can already be observed in the two shorter constructs, the PpsR{sub 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

  20. 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.

  1. Ultrafast Electron Transfer Kinetics in the LM Dimer of Bacterial Photosynthetic Reaction Center from Rhodobacter sphaeroides.

    Science.gov (United States)

    Sun, Chang; Carey, Anne-Marie; Gao, Bing-Rong; Wraight, Colin A; Woodbury, Neal W; Lin, Su

    2016-06-23

    It has become increasingly clear that dynamics plays a major role in the function of many protein systems. One system that has proven particularly facile for studying the effects of dynamics on protein-mediated chemistry is the bacterial photosynthetic reaction center from Rhodobacter sphaeroides. Previous experimental and computational analysis have suggested that the dynamics of the protein matrix surrounding the primary quinone acceptor, QA, may be particularly important in electron transfer involving this cofactor. One can substantially increase the flexibility of this region by removing one of the reaction center subunits, the H-subunit. Even with this large change in structure, photoinduced electron transfer to the quinone still takes place. To evaluate the effect of H-subunit removal on electron transfer to QA, we have compared the kinetics of electron transfer and associated spectral evolution for the LM dimer with that of the intact reaction center complex on picosecond to millisecond time scales. The transient absorption spectra associated with all measured electron transfer reactions are similar, with the exception of a broadening in the QX transition and a blue-shift in the QY transition bands of the special pair of bacteriochlorophylls (P) in the LM dimer. The kinetics of the electron transfer reactions not involving quinones are unaffected. There is, however, a 4-fold decrease in the electron transfer rate from the reduced bacteriopheophytin to QA in the LM dimer compared to the intact reaction center and a similar decrease in the recombination rate of the resulting charge-separated state (P(+)QA(-)). These results are consistent with the concept that the removal of the H-subunit results in increased flexibility in the region around the quinone and an associated shift in the reorganization energy associated with charge separation and recombination. PMID:27243380

  2. Construction and Validation of the Rhodobacter sphaeroides 2.4.1 DNA Microarray: Transcriptome Flexibility at Diverse Growth Modes

    Energy Technology Data Exchange (ETDEWEB)

    Pappas, Christopher T. [University of Wyoming, Laramie; Sram, Jakub [University of Wyoming, Laramie; Moskvin, Oleg V. [University of Wyoming, Laramie; Ivanov, Pavel S. [University of Wyoming, Laramie; Mackenzie, Christopher [University of Texas; Choudhary, Madhusudan [University of Texas; Land, Miriam L [ORNL; Larimer, Frank W [ORNL; Kaplan, Samuel [ORNL; Gomelsky, Mark [University of Wyoming, Laramie

    2004-07-01

    A high-density oligonucleotide DNA microarray, a genechip, representing the 4.6-Mb genome of the facultative phototrophic proteobacterium, Rhodobacter sphaeroides 2.4.1, was custom-designed and manufactured by Affymetrix, Santa Clara, Calif. The genechip contains probe sets for 4,292 open reading frames (ORFs), 47 rRNA and tRNA genes, and 394 intergenic regions. The probe set sequences were derived from the genome annotation generated by Oak Ridge National Laboratory after extensive revision, which was based primarily upon codon usage characteristic of this GC-rich bacterium. As a result of the revision, numerous missing ORFs were uncovered, nonexistent ORFs were deleted, and misidentified start codons were corrected. To evaluate R. sphaeroides transcriptome flexibility, expression profiles for three diverse growth modes-aerobic respiration, anaerobic respiration in the dark, and anaerobic photosynthesis-were generated. Expression levels of one-fifth to one-third of the R. sphaeroides ORFs were significantly different in cells under any two growth modes. Pathways involved in energy generation and redox balance maintenance under three growth modes were reconstructed. Expression patterns of genes involved in these pathways mirrored known functional changes, suggesting that massive changes in gene expression are the major means used by R. sphaeroides in adaptation to diverse conditions. Differential expression was observed for genes encoding putative new participants in these pathways (additional photosystem genes, duplicate NADH dehydrogenase, ATP synthases), whose functionality has yet to be investigated. The DNA microarray data correlated well with data derived from quantitative reverse transcription-PCR, as well as with data from the literature, thus validating the R. sphaeroides genechip as a powerful and reliable tool for studying unprecedented metabolic versatility of this bacterium.

  3. Structural characterization of the B800-850 and B875 light-harvesting antenna complexes from Rhodobacter sphaeroides by electron microscopy

    NARCIS (Netherlands)

    Boonstra, Arjen F.; Visschers, Ronald W.; Calkoen, Florentine; Grondelle, Rienk van; Bruggen, Ernst F.J. van; Boekema, Egbert J.

    1993-01-01

    The structure and aggregation behavior of B800-850 (LHII) and B875 (LHI) antenna complexes of Rhodobacter sphaeroides were studied by electron microscopy. Single molecular projections (top views and side views) of isolated particles were analyzed. The B800-850 complexes, isolated as 150 kDa particle

  4. Identification of key residues that confer Rhodobacter sphaeroides LPS activity at horse TLR4/MD-2.

    Directory of Open Access Journals (Sweden)

    Katherine L Irvine

    Full Text Available The molecular determinants underpinning how hexaacylated lipid A and tetraacylated precursor lipid IVa activate Toll-like receptor 4 (TLR4 are well understood, but how activation is induced by other lipid A species is less clear. Species specificity studies have clarified how TLR4/MD-2 recognises different lipid A structures, for example tetraacylated lipid IVa requires direct electrostatic interactions for agonism. In this study, we examine how pentaacylated lipopolysaccharide from Rhodobacter sphaeroides (RSLPS antagonises human TLR4/MD-2 and activates the horse receptor complex using a computational approach and cross-species mutagenesis. At a functional level, we show that RSLPS is a partial agonist at horse TLR4/MD-2 with greater efficacy than lipid IVa. These data suggest the importance of the additional acyl chain in RSLPS signalling. Based on docking analysis, we propose a model for positioning of the RSLPS lipid A moiety (RSLA within the MD-2 cavity at the TLR4 dimer interface, which allows activity at the horse receptor complex. As for lipid IVa, RSLPS agonism requires species-specific contacts with MD-2 and TLR4, but the R2 chain of RSLA protrudes from the MD-2 pocket to contact the TLR4 dimer in the vicinity of proline 442. Our model explains why RSLPS is only partially dependent on horse TLR4 residue R385, unlike lipid IVa. Mutagenesis of proline 442 into a serine residue, as found in human TLR4, uncovers the importance of this site in RSLPS signalling; horse TLR4 R385G/P442S double mutation completely abolishes RSLPS activity without its counterpart, human TLR4 G384R/S441P, being able to restore it. Our data highlight the importance of subtle changes in ligand positioning, and suggest that TLR4 and MD-2 residues that may not participate directly in ligand binding can determine the signalling outcome of a given ligand. This indicates a cooperative binding mechanism within the receptor complex, which is becoming increasingly

  5. 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

    2011-01-01

    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 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. PMID:21539791

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

    Energy Technology Data Exchange (ETDEWEB)

    Stuart, Thomas A. Cohen [Free Univ. of Amsterdam (Netherlands); Vengris, Mikas [Vilnius Univ. (Lithuania); Novoderezhkin, Vladimir I. [A.N. Belozersky Inst. of Physico-Chemical Biology, Moscow State Univ. (Russia); Cogdell, Richard J. [Microbial Photosynthesis Laboratory, Glasgow Biomedical Research Centre, Univ. of Glasgow (United Kingdom); Hunter, C. Neil [Department of Molecular Biology and Biotechnology, Univ. of Sheffield, (United Kingdom); van Grondelle, Rienk [Free Univ. of Amsterdam (Netherlands)

    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 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.

  7. Photobiological transformation of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) using Rhodobacter sphaeroides.

    Science.gov (United States)

    Millerick, Kayleigh A; Johnston, Juliet T; Finneran, Kevin T

    2016-09-01

    Pump-and-treat strategies for groundwater containing explosives may be necessary when the contaminated water approaches sensitive receptors. This project investigated bacterial photosynthesis as a strategy for ex situ treatment, using light as the primary energy source to facilitate RDX transformation. The objective was to characterize the ability of photosynthetic Rhodobacter sphaeroides (strain ATCC(®) 17023 ™) to transform the high-energy explosive RDX. R. sphaeroides transformed 30 μM RDX within 40 h under light conditions; RDX was not fully transformed in the dark (non-photosynthetic conditions), suggesting that photosynthetic electron transfer was the primary mechanism. Experiments with RDX demonstrated that succinate and malate were the most effective electron donors for photosynthesis, but glycerol was also utilized as a photosynthetic electron donor. RDX was transformed irrespective of the presence of carbon dioxide. The electron shuttling compound anthraquinone-2,6-disulfonate (AQDS) increased transformation kinetics in the absence of CO2, when the cells had excess NADPH that needed to be re-oxidized because there was limited CO2 for carbon fixation. When CO2 was added, the cells generated more biomass, and AQDS had no stimulatory effect. End products indicated that RDX carbon became CO2, biomass, and a soluble, uncharacterized aqueous metabolite, determined using (14)C-labeled RDX. These data are the first to suggest that photobiological explosives transformation is possible and will provide a framework for which phototrophy can be used in environmental restoration of explosives contaminated water. PMID:27285383

  8. Biohydrogen and polyhydroxyalkanoate co-production by Enterobacter aerogenes and Rhodobacter sphaeroides from Calophyllum inophyllum oil cake.

    Science.gov (United States)

    Arumugam, A; Sandhya, M; Ponnusami, V

    2014-07-01

    The feasibility of coupled biohydrogen and polyhydroxyalkanoate production by Enterobacter aerogenes and Rhodobacter sphaeroides using Calophyllum inophyllum oil cake was studied under dark and photo fermentation conditions. The utilization of a non-edible acidic oil cake (C. inophyllum), and exploitation of a modified minimal salt media led to reduction in the cost of media. Cost of fermentation is reduced by implementation of alternate dark-photo fermentative periods and through the use of a co-culture consisting of a dark fermentative (E. aerogenes) and a photo fermentative (R. sphaeroides) bacterium. The biohydrogen and polyhydroxyalkanoate produced were 7.95 L H2/L media and 10.73 g/L media, respectively, under alternate dark and photo fermentation and were 3.23 L H2/L media and 5.6g/L media, respectively under complete dark fermentation. The characteristics of the oil cake and alternate dark (16 h) and photo (8h) fermentative conditions were found to be supportive in producing high biohydrogen and polyhydroxyalkanoate (PHA) yield. PMID:24859207

  9. Experimental measurements of the radiation characteristics of Anabaena variabilis ATCC 29413-U and Rhodobacter sphaeroides ATCC 49419

    Energy Technology Data Exchange (ETDEWEB)

    Berberoglu, Halil; Pilon, Laurent [Mechanical and Aerospace Engineering Department, Henry Samueli School of Engineering and Applied Science, University of California Los Angeles, Los Angeles, CA 90095 (United States)

    2007-12-15

    The objective of this study is to experimentally measure the radiation characteristics of hydrogen producing microorganisms. Special attention is paid to the filamentous cyanobacteria Anabaena variabilis ATCC 29413-U and the unicellular purple bacteria Rhodobacter sphaeroides ATCC 49419 two of the widely studied photobiological hydrogen producers. The extinction and absorption coefficients are measured in the spectral range from 300 to 1300 nm using a spectrophotometer with and without an integrating sphere. Moreover, a nephelometer has been constructed to measure the scattering phase function of the microorganisms at 632.8 nm. The data are used to recover the mass specific absorption, scattering, and extinction cross-sections, the single scattering albedo, and the scattering phase function of the microorganisms. The scattering phase functions of both microorganisms were peaked strongly in the forward direction as expected from their size parameter and shape. The results reported in this study can be used with the radiative transport equation (RTE) to accurately predict and optimize light transport in photobioreactors for photobiological hydrogen production. Finally, the results show that absorption cross-sections of A. variabilis and R. sphaeroides have peaks that do not overlap but rather enlarge the spectral width of the absorption cross-section of a potential symbiotic culture promising more efficient utilization of solar radiation from light transfer point of view. (author)

  10. Biohydrogen and polyhydroxyalkanoate co-production by Enterobacter aerogenes and Rhodobacter sphaeroides from Calophyllum inophyllum oil cake.

    Science.gov (United States)

    Arumugam, A; Sandhya, M; Ponnusami, V

    2014-07-01

    The feasibility of coupled biohydrogen and polyhydroxyalkanoate production by Enterobacter aerogenes and Rhodobacter sphaeroides using Calophyllum inophyllum oil cake was studied under dark and photo fermentation conditions. The utilization of a non-edible acidic oil cake (C. inophyllum), and exploitation of a modified minimal salt media led to reduction in the cost of media. Cost of fermentation is reduced by implementation of alternate dark-photo fermentative periods and through the use of a co-culture consisting of a dark fermentative (E. aerogenes) and a photo fermentative (R. sphaeroides) bacterium. The biohydrogen and polyhydroxyalkanoate produced were 7.95 L H2/L media and 10.73 g/L media, respectively, under alternate dark and photo fermentation and were 3.23 L H2/L media and 5.6g/L media, respectively under complete dark fermentation. The characteristics of the oil cake and alternate dark (16 h) and photo (8h) fermentative conditions were found to be supportive in producing high biohydrogen and polyhydroxyalkanoate (PHA) yield.

  11. Local electrostatic field induced by the carotenoid bound to the reaction center of the purple photosynthetic bacterium Rhodobacter sphaeroides.

    Science.gov (United States)

    Yanagi, Kazuhiro; Shimizu, Madoka; Hashimoto, Hideki; Gardiner, Alastair T; Roszak, Aleksander W; Cogdell, Richard J

    2005-01-20

    Electroabsorption (EA) spectra were recorded in the region of the reaction center (RC) Qy absorption bands of bacteriochlorophyll (Bchl) and bacteriopheophytin, to investigate the effect of carotenoid (Car) on the electrostatic environment of the RCs of the purple bacterium Rhodobacter (Rb.) sphaeroides. Two different RCs were prepared from Rb. sphaeroides strain R26.1 (R26.1-RC); R26.1 RC lacking Car and a reconstituted RC (R26.1-RC+ Car) prepared by incorporating a synthetic Car (3,4-dihydrospheroidene). Although there were no detectable differences between these two RCs in their near infrared (NIR) absorption spectra at 79 and 293 K, or in their EA spectra at 79 K, significant differences were detected in their EA spectra at 293 K. Three nonlinear optical parameters of each RC were determined in order to evaluate quantitatively these differences; transition dipole-moment polarizability and hyperpolarizability (D factor), the change in polarizability upon photoexcitation (Deltaalpha), and the change in dipole-moment upon photoexcitation (Deltamu). The value of D or Deltaalpha determined for each absorption band of the two RC samples showed similar values at 77 or 293 K. However, the Deltamu values of the special pair Bchls (P) and the monomer Bchls absorption bands showed significant differences between the two RCs at 293 K. X-ray crystallography of the two RCs has revealed that a single molecule of the solubilizing detergent LDAO occupies part of the carotenoid binding site in the absence of a carotenoid. The difference in the value of Deltamu therefore represents the differential effect of the detergent LDAO and the carotenoid on P. The change of electrostatic field around P induced by the presence of Car was determined to be 1.7 x 10(5) [V/cm], corresponding to a approximately 10% change in the electrostatic field around P.

  12. Biohydrogen production by purple non-sulfur bacteria Rhodobacter sphaeroides: Effect of low-intensity electromagnetic irradiation.

    Science.gov (United States)

    Gabrielyan, Lilit; Sargsyan, Harutyun; Trchounian, Armen

    2016-09-01

    The present work was focused on the effects of low-intensity (the flux capacity was of 0.06mWcm(-2)) electromagnetic irradiation (EMI) of extremely high frequencies or millimeter waves on the growth and hydrogen (H2) photoproduction by purple non-sulfur bacteria Rhodobacter sphaeroides MDC6521 (from Armenian mineral springs). After exposure of R. sphaeroides, grown under anaerobic conditions upon illumination, to EMI (51.8GHz and 53.0GHz) for 15min an increase of specific growth rate by ~1.2-fold, in comparison with control (non-irradiated cells), was obtained. However, the effect of EMI depends on the duration of irradiation: the exposure elongation up to 60min caused the delay of the growth lag phase and the decrease specific growth rate by ~1.3-fold, indicating the bactericidal effect of EMI. H2 yield of the culture, irradiated by EMI for 15min, determined during 72h growth, was ~1.2-fold higher than H2 yield of control cells, whereas H2 production by cultures, irradiated by EMI for 60min was not observed during 72h growth. This difference in the effects of extremely high frequency EMI indicates a direct effect of radiation on the membrane transfer and the enzymes of these bacteria. Moreover, EMI increased DCCD-inhibited H(+) fluxes across the bacterial membrane and DCCD-sensitive ATPase activity of membrane vesicles, indicating that the proton FoF1-ATPase is presumably a basic target for extremely high frequency EMI related to H2 production by cultures. PMID:27479839

  13. Modeling the light- and redox-dependent interaction of PpsR/AppA in Rhodobacter sphaeroides.

    Science.gov (United States)

    Pandey, Rakesh; Flockerzi, Dietrich; Hauser, Marcus J B; Straube, Ronny

    2011-05-18

    Facultative photosynthetic bacteria switch their energy generation mechanism from respiration to photosynthesis depending on oxygen tension and light. Part of this transition is mediated by the aerobic transcriptional repressor PpsR. In Rhodobacter sphaeroides, the repressive action of PpsR is antagonized by the redox- and blue-light-sensitive flavoprotein AppA which results in a unique phenotype: the repression of photosynthesis genes at intermediate oxygen levels and high light intensity, which is believed to reduce the risk of photooxidative stress. To analyze the underlying mechanism we developed a simple mathematical model based on the AppA-dependent reduction of a disulfide bond in PpsR and the light-sensitive complex formation between the reduced forms of AppA and PpsR. A steady-state analysis shows that high light repression can indeed occur at intermediate oxygen levels if PpsR is reduced on a faster timescale than AppA and if the electron transfer from AppA to PpsR is effectively irreversible. The model further predicts that if AppA copy numbers exceed those of PpsR by at least a factor of two, the transition from aerobic to anaerobic growth mode can occur via a bistable regime. We provide necessary conditions for the emergence of bistability and discuss possible experimental verifications.

  14. Physiological Roles for Two Periplasmic Nitrate Reductases in Rhodobacter sphaeroides 2.4.3 (ATCC 17025)▿

    Science.gov (United States)

    Hartsock, Angela; Shapleigh, James P.

    2011-01-01

    The metabolically versatile purple bacterium Rhodobacter sphaeroides 2.4.3 is a denitrifier whose genome contains two periplasmic nitrate reductase-encoding gene clusters. This work demonstrates nonredundant physiological roles for these two enzymes. One cluster is expressed aerobically and repressed under low oxygen while the second is maximally expressed under low oxygen. Insertional inactivation of the aerobically expressed nitrate reductase eliminated aerobic nitrate reduction, but cells of this strain could still respire nitrate anaerobically. In contrast, when the anaerobic nitrate reductase was absent, aerobic nitrate reduction was detectable, but anaerobic nitrate reduction was impaired. The aerobic nitrate reductase was expressed but not utilized in liquid culture but was utilized during growth on solid medium. Growth on a variety of carbon sources, with the exception of malate, the most oxidized substrate used, resulted in nitrite production on solid medium. This is consistent with a role for the aerobic nitrate reductase in redox homeostasis. These results show that one of the nitrate reductases is specific for respiration and denitrification while the other likely plays a role in redox homeostasis during aerobic growth. PMID:21949073

  15. Concomitant biohydrogen and poly-β-hydroxybutyrate production from dark fermentation effluents by adapted Rhodobacter sphaeroides and mixed photofermentative cultures.

    Science.gov (United States)

    Ghimire, Anish; Valentino, Serena; Frunzo, Luigi; Pirozzi, Francesco; Lens, Piet N L; Esposito, Giovanni

    2016-10-01

    This work aimed at investigating concomitant production of biohydrogen and poly-β-hydroxybutyrate (PHB) by photofermentation (PF) using dark fermentation effluents (DFE). An adapted culture of Rhodobacter sphaeroides AV1b (pH 6.5, 24±2°C) achieved H2 and PHB yields of 256 (±2) NmLH2/g Chemical Oxygen Demand (COD) and 273.8mgPHB/gCOD (32.5±3% of the dry cells weight (DCW)), respectively. When a diluted (1:2) DFE medium was applied to the adapted pure and mixed photofermentative culture, the respective H2 yields were 164.0 (±12) and 71.3 (±6) NmLH2/gCOD and the PHB yields were 212.1 (±105.2) and 50.7 (±2.7) mgPHB/gCOD added, corresponding to 24 (±0.7) and 6.3 (±0) % DCW, respectively. The concomitant H2 and PHB production from the PF process gave a good DFE post treatment achieving up to 80% COD removal from the initial DFE. PMID:27005789

  16. Electronic Structure and Dynamics of Higher-Lying Excited States in Light Harvesting Complex 1 from Rhodobacter sphaeroides.

    Science.gov (United States)

    Dahlberg, Peter D; Ting, Po-Chieh; Massey, Sara C; Martin, Elizabeth C; Hunter, C Neil; Engel, Gregory S

    2016-06-23

    Light harvesting in photosynthetic organisms involves efficient transfer of energy from peripheral antenna complexes to core antenna complexes, and ultimately to the reaction center where charge separation drives downstream photosynthetic processes. Antenna complexes contain many strongly coupled chromophores, which complicates analysis of their electronic structure. Two-dimensional electronic spectroscopy (2DES) provides information on energetic coupling and ultrafast energy transfer dynamics, making the technique well suited for the study of photosynthetic antennae. Here, we present 2DES results on excited state properties and dynamics of a core antenna complex, light harvesting complex 1 (LH1), embedded in the photosynthetic membrane of Rhodobacter sphaeroides. The experiment reveals weakly allowed higher-lying excited states in LH1 at 770 nm, which transfer energy to the strongly allowed states at 875 nm with a lifetime of 40 fs. The presence of higher-lying excited states is in agreement with effective Hamiltonians constructed using parameters from crystal structures and atomic force microscopy (AFM) studies. The energy transfer dynamics between the higher- and lower-lying excited states agree with Redfield theory calculations. PMID:27232937

  17. Concomitant biohydrogen and poly-β-hydroxybutyrate production from dark fermentation effluents by adapted Rhodobacter sphaeroides and mixed photofermentative cultures.

    Science.gov (United States)

    Ghimire, Anish; Valentino, Serena; Frunzo, Luigi; Pirozzi, Francesco; Lens, Piet N L; Esposito, Giovanni

    2016-10-01

    This work aimed at investigating concomitant production of biohydrogen and poly-β-hydroxybutyrate (PHB) by photofermentation (PF) using dark fermentation effluents (DFE). An adapted culture of Rhodobacter sphaeroides AV1b (pH 6.5, 24±2°C) achieved H2 and PHB yields of 256 (±2) NmLH2/g Chemical Oxygen Demand (COD) and 273.8mgPHB/gCOD (32.5±3% of the dry cells weight (DCW)), respectively. When a diluted (1:2) DFE medium was applied to the adapted pure and mixed photofermentative culture, the respective H2 yields were 164.0 (±12) and 71.3 (±6) NmLH2/gCOD and the PHB yields were 212.1 (±105.2) and 50.7 (±2.7) mgPHB/gCOD added, corresponding to 24 (±0.7) and 6.3 (±0) % DCW, respectively. The concomitant H2 and PHB production from the PF process gave a good DFE post treatment achieving up to 80% COD removal from the initial DFE.

  18. Characterization of ‘Pinky’ Strain Grown in Culture of Rhodobacter sphaeroides R26.1

    Institute of Scientific and Technical Information of China (English)

    PAN Yan; XIE Jing; KOYAMA Yasushi; LI Shi-hao; WANG En-si; HOU A-li

    2013-01-01

    In the process of cultivating Rhodobater sphaeroides R26.1,some of which turned from blue to pink due to the irradiation of a beam of leaking white light.The mutant strains were named ‘pinky’ strains,which were cultivated in the red light and in the dark for a comparative study.It turned out that the strains did not grow in the dark,so they might be photosynthetic bacteria.The electronic absorption spectrum of the ‘pinky’ strains was measured,which shows they contained two main photosynthetic pigments,carotenoids(Cars) and bacteriochlorophylls(BChls).And then they were extracted and analyzed.It proves that Bchls included Bchl a and Bchl a'.Nuclear magnetic resonance (NMR) spectra were exploited to determine the chemical structure of Cars.The results indicate that there were seven kinds of Cars,including lycopene,rhodopin,anhydrorhodovibrin,3,4-dihydroanhydrorhodovibrin,3,3,4-dihydrospirilloxanthin,3,4,3',4'-tetrahydrospirilloxanthin and spirilloxanthin.Based on the above results,it was found that most identified Cars formed via spirilloxanthin biosynthesis pathway.The analyzed results of 16S rRNA gene show that the homology of ‘pinky’ strains with Rhodopseudomonas palusteris was 99%.Rhodopseudomonas palusteris has been cultivated in our laboratory.Because of its strong vitality,it did not become extinct with so many years passing.When Rhodobater sphaeroides R26.1 was cultivated,it got rejuvenated under the appropriate conditions and caused Rhodobater sphaeroides R26.1 to be contaminated.

  19. Whole-genome shotgun optical mapping of Rhodobacter sphaeroides strain 2.4. 1 and its use for whole-genome shotgun sequence assembly

    Energy Technology Data Exchange (ETDEWEB)

    Shou, S. [Univ. Wisc.-Madison; Kvikstad, E. [Univ. Wisc.-Madison; Kile, A. [Univ. Wisc.-Madison; Severin, J. [Whole-genome shotgun optical mapping of Rhodobacter sphaeroides strain 2.4. 1 and its use for whole-genome shotgun sequence assembly; Forrest, D. [Univ. Wisc.-Madison; Runnheim, R. [Univ. Wisc.-Madison; Churas, C. [Univ. Wisc.-Madison; Hickman, J. W. [Univ. Wisc.-Madison; Mackenzie, C. [University of Texas–Houston Medical School; Choudhary, M. [University of Texas–Houston Medical School; Donohue, T. [Univ. Wisc.-Madison; Kaplan, S. [University of Texas–Houston Medical School; Schwartz, D. C. [Univ. Wisc.-Madison

    2003-09-01

    Rhodobacter sphaeroides 2.4.1 is a facultative photoheterotrophic bacterium with tremendous metabolic diversity, which has significantly contributed to our understanding of the molecular genetics of photosynthesis, photoheterotrophy, nitrogen fixation, hydrogen metabolism, carbon dioxide fixation, taxis, and tetrapyrrole biosynthesis. To further understand this remarkable bacterium, and to accelerate an ongoing sequencing project, two whole-genome restriction maps (EcoRI and HindIII) of R. sphaeroides strain 2.4.1 were constructed using shotgun optical mapping. The approach directly mapped genomic DNA by the random mapping of single molecules. The two maps were used to facilitate sequence assembly by providing an optical scaffold for high-resolution alignment and verification of sequence contigs. Our results show that such maps facilitated the closure of sequence gaps by the early detection of nascent sequence contigs during the course of the whole-genome shotgun sequencing process.

  20. Effect of the mutation of carotenoids on the dynamics of energy transfer in light- harvesting complexes (LH2) from Rhodobacter sphaeroides 601 at room temperature

    Institute of Scientific and Technical Information of China (English)

    Liu Wei-Min; Liu Yuan; Liu Rang-Jun; Yan Yong-Li; Guo Li-Jun; Xu Chun-He; Qian Shi-Xiong

    2006-01-01

    Energy transfers in two kinds of peripheral light-harvesting complexes (LH2) of Rhodobacter sphaeroides (RS) 601 are studied by using femtosecond pump-probe spectroscopy with tunable laser wavelength at room temperature. These two complexes are native LH2 (RS601) and green carotenoid mutated LH2 (GM309). The obtained results demonstrate that, compared with spheroidenes with ten conjugated double bonds in native RS601, carotenoid in GM309 containing neurosporenes with nine conjugated double bonds can lead to a reduction in energy transfer rate in the B800-to-B850 band and the disturbance in the energy relaxation processes within the excitonic B850 band.

  1. PucC and LhaA direct efficient assembly of the light-harvesting complexes in Rhodobacter sphaeroides

    DEFF Research Database (Denmark)

    Mothersole, David; Jackson, Philip J.; Vasilev, Cvetelin;

    2016-01-01

    interactions between pigments newly arriving from BchG and nascent proteins within the SecYEG-SecDF-YajC-YidC assembly machinery, thereby co-ordinating pigment delivery, the co-translational insertion of LH polypeptides and their folding and assembly to form photosynthetic complexes.......The mature architecture of the photosynthetic membrane of the purple phototroph Rhodobacter sphaeroides has been characterised to a level where an atomic-level membrane model is available, but the roles of the putative assembly proteins LhaA and PucC in establishing this architecture are unknown...

  2. Stable Carbon Isotope Discrimination by Form IC Rubisco Enzymes of the Extremely Metabolically Versatile Rhodobacter sphaeroides and Ralstonia eutropha}

    Science.gov (United States)

    Thomas, P. J.; Boller, A. J.; Zhao, Z.; Tabita, F. R.; Cavanaugh, C. M.; Scott, K. M.

    2006-12-01

    Variations in the relative amounts of 12C and 13C in microbial biomass can be used to infer the pathway(s) autotrophs use to fix and assimilate dissolved inorganic carbon. Discrimination against 13C by the enzymes catalyzing autotrophic carbon fixation is a major factor dictating biomass stable carbon isotopic compositions (δ13C = {[13C/12Csample/13C/12Cstandard] - 1} × 1000). Five different forms of RubisCO (IA, IB, IC, ID, and II) are utilized by algae and autotrophic bacteria reliant on the Calvin-Benson cycle for carbon fixation. To date, isotope discrimination has been measured for form IA, IB, and II RubisCOs, and their ɛ values (={[12k/13k] - 1} × 1000; 12k and 13k = rates of 12C and 13C fixation) range from 18 to 29‰, explaining the variation in biomass δ13C values of autotrophs utilizing these enzymes. Isotope discrimination by form IC RubisCO has not been measured, despite the presence of this enzyme in many proteobacteria of ecological interest, including marine manganese-oxidizing bacteria, some nitrifying and nitrogen-fixing bacteria, and extremely metabolically versatile organisms such as Rhodobacter sphaeroides and Ralstonia eutropha. The purpose of this work was to determine the ɛ values for form IC RubisCO enzymes from R. sphaeroides and R. eutropha. Recombinant form IC RubisCOs were purified by conventional column chromatography procedures. Assay conditions (pH, dissolved inorganic carbon concentration) were tested to determine which parameters were conducive to the high rates of carbon fixation necessary for ɛ determination. Under standard conditions (pH 8.5 and 5 mM DIC), form IC RubisCO activities were sufficient for ɛ determination. Experiments are currently being conducted to measure the ɛ values of these enzymes. Sampling the full phylogenetic breadth of RubisCO enzymes for isotopic discrimination makes it possible to constrain the range of δ13C values of organisms fixing carbon via the Calvin-Benson cycle. These results are

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

    Science.gov (United States)

    2016-01-01

    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. PMID:27285777

  4. Antioxidant Activity of Carotenoids from Rhodobacter sphaeroides%类球红细菌类胡萝卜素抗氧化活性研究

    Institute of Scientific and Technical Information of China (English)

    安君; 李祖明; 张静; 白志辉; 杨卫东; 王栋

    2015-01-01

    The effects of grinding, ultrasonic, ultrasonic assisted with acidolysis and thallus concentration on antioxi-dant activity of carotenoids from Rhodobacter sphaeroides were studied in this paper.The results showed that the carot-enoids extracted with different methods and solid-liquid proportion from R.sphaeroides 3757 possessed activities of scavenging DPPH free radicals, reducing power and resistance against lipid peroxidation.Carotenoids extracted by ul-trasonic assisted with acidolysis from R.sphaeroides 3757 has the highest production rate and the best antioxidant ac-tivities.Caratenoids from R.sphaeroides possessed a certain antioxidant activities, and the antioxidant activities in-creased as the thallus concentration increased.%研究了研磨法、超声波法、酸溶辅助超声波法和菌体浓度对类球红细菌类胡萝卜素抗氧化活性的影响。结果表明,不同提取方法和固液比条件下,类球红细菌类胡萝卜素均具有清除DPPH自由基能力、抗脂质过氧化能力和还原能力。酸溶辅助超声波法提取的类胡萝卜素产率最高、抗氧化活性最好。类球红细菌类胡萝卜素具有一定的抗氧化活性,其抗氧化活性随菌体浓度的增加而增加。

  5. Femtosecond Dynamics of Energy Transfer in Native B800-B850 and B800-Released LH2 Complexes of Rhodobacter Sphaeroides

    Institute of Scientific and Technical Information of China (English)

    刘伟民; 朱荣毅; 夏辰安; 刘源; 徐春和; 钱士雄

    2003-01-01

    Two kinds of antenna complexes LH2 of Rhodobacter sphaeroides, wild type RS601 and the removal of B800 pigments (B800-released), were used in our experiment. These two LH2 complexes show quite different behaviour in absorption and femtosecond dynamics. By using the femtosecond pump-probe technique, the energy transfer processes occurring in two complexes were studied. Because of removing the B800 pigment from the LH2 in B800-released LH2 complex, the energy transfer between the B800 to B850 pigment was completely eliminated,while the pure internal energy transfer within the exciton states of B850 pigment could be carefully investigated.The results show that, at B800 absorption band, B800-released LH2 obviously shows a dominated transient absorption different from the photobleaching observed in RS601; while at the B850 band, these two complexes show similar photobleaching behaviour.

  6. The nature of the lower excited state of the special pair of bacterial photosynthetic reaction center of Rhodobacter Sphaeroides and the dynamics of primary charge separation

    Science.gov (United States)

    Ivashin, N. V.; Shchupak, E. E.

    2016-08-01

    Quantum-chemical calculations of the structure in the ground and lower singlet excited states and the vibrations (in the ground state) of special pair P of photosynthetic reaction center of purple bacteria (RCPb) Rhodobacter Sphaeroides, consisting of two bacteriochlorophyll molecules PA and PB, have been carried out. It is shown that excitation of the special pair is followed by fast relaxation dynamics, accompanied by the transformation of the initial P* state into the P A δ+ P B δ- state (δ ~ 0.5) with charge separation. This behavior is due to the presence of several nonplanar vibrations with participation of the acetyl group of macrocycle PB in the nuclear wave packet on the potential surface of the P* state; these vibrations facilitate destabilization of the lowest unoccupied molecular orbital (LUMO) and highest occupied molecular orbital (HOMO) of the macrocycle PA and formation of the P A δ+ P B δ- state. The structural transformations in the P* state are due to its linking character in the contact region of the acetyl group-containing pyrrole rings of PA and PB. The transition from the P* state to specifically the P A δ+ P B δ- state is related to the fact that the acetyl group PA is involved in the intermolecular hydrogen bond with amino acid residue HisL168; for this reason, this group and the pyrrole ring linked with it can hardly participate in structural transformations. The electronic matrix element H12 of the electron transfer from the special pair in the P A δ+ P B δ- state to a molecule of accessory bacteriochlorophyll BA greatly exceeds that for the transfer to BB. This circumstance and the fact that the P A δ+ P B δ- state is energetically more favorable than the P* state facilitate the preferred directionality of the electron transfer in RCPb Rhodobacter Sphaeroides with participation of the cofactors located in its subunit L.

  7. Absence of the cbb3 Terminal Oxidase Reveals an Active Oxygen-Dependent Cyclase Involved in Bacteriochlorophyll Biosynthesis in Rhodobacter sphaeroides

    Science.gov (United States)

    Chen, Guangyu E.; Martin, Elizabeth C.; Hunter, C. Neil

    2016-01-01

    ABSTRACT The characteristic green color associated with chlorophyll pigments results from the formation of an isocyclic fifth ring on the tetrapyrrole macrocycle during the biosynthesis of these important molecules. This reaction is catalyzed by two unrelated cyclase enzymes employing different chemistries. Oxygenic phototrophs such as plants and cyanobacteria utilize an oxygen-dependent enzyme, the major component of which is a diiron protein named AcsF, while BchE, an oxygen-sensitive [4Fe-4S] cluster protein, dominates in phototrophs inhabiting anoxic environments, such as the purple phototrophic bacterium Rhodobacter sphaeroides. We identify a potential acsF in this organism and assay for activity of the encoded protein in a strain lacking bchE under various aeration regimes. Initially, cells lacking bchE did not demonstrate AcsF activity under any condition tested. However, on removal of a gene encoding a subunit of the cbb3-type respiratory terminal oxidase, cells cultured under regimes ranging from oxic to micro-oxic exhibited cyclase activity, confirming the activity of the oxygen-dependent enzyme in this model organism. Potential reasons for the utilization of an oxygen-dependent enzyme in anoxygenic phototrophs are discussed. IMPORTANCE The formation of the E ring of bacteriochlorophyll pigments is the least well characterized step in their biosynthesis, remaining enigmatic for over 60 years. Two unrelated enzymes catalyze this cyclization step; O2-dependent and O2-independent forms dominate in oxygenic and anoxygenic phototrophs, respectively. We uncover the activity of an O2-dependent enzyme in the anoxygenic purple phototrophic bacterium Rhodobacter sphaeroides, initially by inactivation of the high-affinity terminal respiratory oxidase, cytochrome cbb3. We propose that the O2-dependent form allows for the biosynthesis of a low level of bacteriochlorophyll under oxic conditions, so that a rapid initiation of photosynthetic processes is possible for

  8. 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)

  9. A distant homologue of the FlgT protein interacts with MotB and FliL and is essential for flagellar rotation in Rhodobacter sphaeroides.

    Science.gov (United States)

    Fabela, Salvador; Domenzain, Clelia; De la Mora, Javier; Osorio, Aurora; Ramirez-Cabrera, Victor; Poggio, Sebastian; Dreyfus, Georges; Camarena, Laura

    2013-12-01

    In this work, we describe a periplasmic protein that is essential for flagellar rotation in Rhodobacter sphaeroides. This protein is encoded upstream of flgA, and its expression is dependent on the flagellar master regulator FleQ and on the class III flagellar activator FleT. Sequence comparisons suggest that this protein is a distant homologue of FlgT. We show evidence that in R. sphaeroides, FlgT interacts with the periplasmic regions of MotB and FliL and with the flagellar protein MotF, which was recently characterized as a membrane component of the flagellum in this bacterium. In addition, the localization of green fluorescent protein (GFP)-MotF is completely dependent on FlgT. The Mot(-) phenotype of flgT cells was weakly suppressed by point mutants of MotB that presumably keep the proton channel open and efficiently suppress the Mot(-) phenotype of motF and fliL cells, indicating that FlgT could play an additional role beyond the opening of the proton channel. The presence of FlgT in purified filament-hook-basal bodies of the wild-type strain was confirmed by Western blotting, and the observation of these structures under an electron microscope showed that the basal bodies from flgT cells had lost the ring that covers the LP ring in the wild-type structure. Moreover, MotF was detected by immunoblotting in the basal bodies obtained from the wild-type strain but not from flgT cells. From these results, we suggest that FlgT forms a ring around the LP ring, which anchors MotF and stabilizes the stator complex of the flagellar motor. PMID:24056105

  10. Functional assembly of the foreign carotenoid lycopene into the photosynthetic apparatus of Rhodobacter sphaeroides, achieved by replacement of the native 3-step phytoene desaturase with its 4-step counterpart from Erwinia herbicola.

    Science.gov (United States)

    Garcia-Asua, Guillermo; Cogdell, Richard J; Hunter, C Neil

    2002-04-01

    Photosynthetic organisms synthesize a diverse range of carotenoids. These pigments are important for the assembly, function and stability of photosynthetic pigment-protein complexes, and they are used to quench harmful radicals. The photosynthetic bacterium Rhodobacter sphaeroides was used as a model system to explore the origin of carotenoid diversity. Replacing the native 3-step phytoene desaturase (CrtI) with the 4-step enzyme from Erwinia herbicola results in significant flux down the spirilloxanthin pathway for the first time in Rb. sphaeroides. In Rb. sphaeroides, the completion of four desaturations to lycopene by the Erwinia CrtI appears to require the absence of CrtC and, in a crtC background, even the native 3-step enzyme can synthesize a significant amount (13%) of lycopene, in addition to the expected neurosporene. We suggest that the CrtC hydroxylase can intervene in the sequence of reactions catalyzed by phytoene desaturase. We investigated the properties of the lycopene-synthesizing strain of Rb. sphaeroides. In the LH2 light-harvesting complex, lycopene transfers absorbed light energy to the bacteriochlorophylls with an efficiency of 54%, which compares favourably with other LH2 complexes that contain carotenoids with 11 conjugated double bonds. Thus, lycopene can join the assembly pathway for photosynthetic complexes in Rb. sphaeroides, and can perform its role as an energy donor to bacteriochlorophylls. PMID:11967082

  11. Functional assembly of the foreign carotenoid lycopene into the photosynthetic apparatus of Rhodobacter sphaeroides, achieved by replacement of the native 3-step phytoene desaturase with its 4-step counterpart from Erwinia herbicola.

    Science.gov (United States)

    Garcia-Asua, Guillermo; Cogdell, Richard J; Hunter, C Neil

    2002-04-01

    Photosynthetic organisms synthesize a diverse range of carotenoids. These pigments are important for the assembly, function and stability of photosynthetic pigment-protein complexes, and they are used to quench harmful radicals. The photosynthetic bacterium Rhodobacter sphaeroides was used as a model system to explore the origin of carotenoid diversity. Replacing the native 3-step phytoene desaturase (CrtI) with the 4-step enzyme from Erwinia herbicola results in significant flux down the spirilloxanthin pathway for the first time in Rb. sphaeroides. In Rb. sphaeroides, the completion of four desaturations to lycopene by the Erwinia CrtI appears to require the absence of CrtC and, in a crtC background, even the native 3-step enzyme can synthesize a significant amount (13%) of lycopene, in addition to the expected neurosporene. We suggest that the CrtC hydroxylase can intervene in the sequence of reactions catalyzed by phytoene desaturase. We investigated the properties of the lycopene-synthesizing strain of Rb. sphaeroides. In the LH2 light-harvesting complex, lycopene transfers absorbed light energy to the bacteriochlorophylls with an efficiency of 54%, which compares favourably with other LH2 complexes that contain carotenoids with 11 conjugated double bonds. Thus, lycopene can join the assembly pathway for photosynthetic complexes in Rb. sphaeroides, and can perform its role as an energy donor to bacteriochlorophylls.

  12. Effects of ammonium ion, acetate and aerobic conditions on hydrogen production and expression levels of nitrogenase genes in Rhodobacter sphaeroides O.U.001

    Energy Technology Data Exchange (ETDEWEB)

    Akkoese, Sevilay; Guenduez, Ufuk; Yuecel, Meral [Middle East Technical University, Department of Biological Sciences, 06531 Ankara (Turkey); Eroglu, Inci [Middle East Technical University, Department of Chemical Engineering, 06531 Ankara (Turkey)

    2009-11-15

    In the present study, expression levels of nitrogenase encoding nifH and control genes nifA and prrA were examined at different physiological conditions in Rhodobacter sphaeroides O.U.001. In addition to variations in expression levels, changes in hydrogen production and growth were also investigated in response to different concentrations of ammonium source, acetate and aerobic conditions. In the present study, increasing concentration of ammonium chloride was found to be caused decrease in hydrogen production. Glutamate containing medium had the capacity for higher hydrogen production. Hydrogen production was observed even in aerobic conditions. The expression levels of nifH and nifA genes decreased with the increasing concentrations of ammonium chloride. Although the expression of nifA was present in the highest concentrations of NH{sub 4}Cl under anaerobic conditions, no expression was observed under aerobic conditions of the same culture conditions. This was likely due to transcriptional level inhibition of nitrogenase in the presence of ammonium ion. Negative correlation was observed between the expression levels of prrA gene and its target, nifA gene. (author)

  13. 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.

  14. 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

  15. The roles of Rhodobacter sphaeroides copper chaperones PCuAC and Sco (PrrC) in the assembly of the copper centers of the aa3-type and the cbb3-type cytochrome c oxidases

    OpenAIRE

    Thompson, Audie K.; Gray, Jimmy; Liu, Aimin; Hosler, Jonathan P.

    2012-01-01

    The α proteobacter Rhodobacter sphaeroides accumulates two cytochrome c oxidases (CcO) in its cytoplasmic membrane during aerobic growth: a mitochondrial-like aa3-type CcO containing a di-copper CuA center and mono-copper CuB, plus a cbb3-type CcO that contains CuB but lacks CuA. Three copper chaperones are located in the periplasm of R. sphaeroides, PCuAC, PrrC (Sco) and Cox11. Cox11 is required to assemble CuB of the aa3-type but not the cbb3-type CcO. PrrC is homologous to mitochondrial Sc...

  16. Monomeric RC-LH1 core complexes retard LH2 assembly and intracytoplasmic membrane formation in PufX-minus mutants of Rhodobacter sphaeroides

    Energy Technology Data Exchange (ETDEWEB)

    Adams, Peter G. [University of Sheffield (United Kingdom); Mothersole, David J. [University of Sheffield (United Kingdom); Ng, Irene W. [University of Sheffield (United Kingdom); Olsen, John D. [University of Sheffield (United Kingdom); Hunter, C. Neil [University of Sheffield (United Kingdom)

    2011-01-01

    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.

  17. Determination of the total triterpenes in mistletoe transformed by rhodobac-ter sphaeroides%球形红细菌生物转化槲寄生中总三萜类化合物的测定

    Institute of Scientific and Technical Information of China (English)

    侯晓峰; 郑庆红; 漆小梅; 杨官娥; 张肇铭

    2011-01-01

    Objective: To establish methods for the determination of total triterpenes in mistletoe and its transformation products by rhodobacter sphaeroides, and to compare the contents of each sample. Methods: Oleanolic acid was taken as the standard, the content of total triterpenes was measured by spectrophotometry with 5% vanillin-glacial acetic acid solution and perchloric acid as color-developing agent and the detection wavelength was at 535 nm. Results: The linear correlation of oleanolic acid calibration curve was good in the range of 2-12 |jLg/ml, and the calibration curve regression equation was A =21.988C-0.072, r=0.989 5. Compared with 75% ethanol extract of mistletoe (sample 1), the content of total triterpenes in 75% ethanol mistletoe extract cultured with half amount of conventional medium and rhodobacter sphaeroides (sample 3) increased by 141%. Conclusion: The content of total triterpenes in mistletoe extract can be enhanced after bio-umand by rhodobacter sphaeroides%目的:建立槲寄生及球形红细菌转化槲寄生培养液中总三萜类化合物的含量测定方法,并对各个样品的含量进行比较研究.方法:采用紫外分光光度法,以齐墩果酸为对照品,5%的香草醛-冰醋酸溶液和高氯酸为显色系统,535 nm 波长处测定总三萜类化合物的含量.结果:齐墩果酸在2~12 μg/ml 的范围内线性关系良好,标准曲线回归方程为A=21.988C-0.072,r=0.989 5.75%的乙醇提取、半量常规培养基、游离球形红细菌培养,所得培养液(样品3)总三萜含量和槲寄生75%的乙醇提取液(样品1)相比增加141%.结论:经过球形红细菌转化可以增加槲寄生提取液中总三萜类化合物的含量.

  18. Relationship of proton motive force and the F(0)F (1)-ATPase with bio-hydrogen production activity of Rhodobacter sphaeroides: effects of diphenylene iodonium, hydrogenase inhibitor, and its solvent dimethylsulphoxide.

    Science.gov (United States)

    Hakobyan, Lilit; Gabrielyan, Lilit; Trchounian, Armen

    2012-08-01

    Rhodobacter sphaeroides MDC 6521 was able to produce bio-hydrogen (H(2)) in anaerobic conditions under illumination. In this study the effects of the hydrogenase inhibitor-diphenylene iodonium (Ph(2)I) and its solvent dimethylsulphoxide (DMSO) on growth characteristics and H(2) production by R. sphaeroides were investigated. The results point out the concentration dependent DMSO effect: in the presence of 10 mM DMSO H(2) yield was ~6 fold lower than that of the control. The bacterium was unable to produce H(2) in the presence of Ph(2)I. In order to examine the mediatory role of proton motive force (∆p) or the F(0)F(1)-ATPase in H(2) production by R. sphaeroides, the effects of Ph(2)I and DMSO on ∆p and its components (membrane potential (∆ψ) and transmembrane pH gradient), and ATPase activity were determined. In these conditions ∆ψ was of -98 mV and the reversed ∆pH was +30 mV, resulting in ∆p of -68 mV. Ph(2)I decreased ∆ψ in concentrations of 20 μM and higher; lower concentrations of Ph(2)I as DMSO had no valuable effect on ∆ψ. The R. sphaeroides membrane vesicles demonstrated significant ATPase activity sensitive to N,N'-dicyclohexylcarbodiimide. The 10-20 μM Ph(2)I did not affect the ATPase activity, whereas 40 μM Ph(2)I caused a marked inhibition (~2 fold) in ATPase activity. The obtained results provide novel evidence on the involvement of hydrogenase and the F(0)F(1)-ATPase in H(2) production by R. sphaeroides. Moreover, these data indicate the role of hydrogenase and the F(0)F(1)-ATPase in ∆p generation. In addition, DMSO might increase an interaction of nitrogenase with CO(2), decreasing nitrogenase activity and affecting H(2) production.

  19. 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.

  20. Protoplast Preparation and Regeneration of Coenzyme Q10 Producing Strain Rhodobacter sphaeroides%产辅酶Q10的类球红细菌原生质体制备和再生研究

    Institute of Scientific and Technical Information of China (English)

    宋丽雅; 乔志新; 李伟静; 贺敏; 赵华; 于群

    2012-01-01

    Coenzyme Q10 (CoQ10 ) is an endogenous enzyme cofactor that may be found in every cell in the human body and an important natural antioxidant widely used in many fields, such as medicine, food and cosmetics. The protoplast fusion is an important process in the genome shuffling. In order to improve the efficiency of the genome shuffling and the CoQ10 production, this paper studies the conditions of the protoplast preparation and the regeneration of CoQ10 to produce the strain Rhodobacter sphaeroides. The parameters of the proper protoplast formation and the regeneration were determined through the growth curve and the orthogonal experiment: the lysozyme concentration is 1mg/mL, the enzymatic temperature is 37℃; the enzymatic time is 1h and the sucrose concentration is 10%, and under these conditions, the protoplast formation rate is 96.1% and the protoplast regeneration rate reaches 28.8%. Therefore, the optimized conditions of the protoplast preparation and the regeneration for the genome shuffling of Rhodobacter sphaeroides are obtained.%辅酶Q10(CoQ10)是人类细胞自身产生的内源性辅酶因子,是一类天然抗氧化剂,目前已广泛应用于医药、食品、化妆品等诸多领域.基因组改组技术的核心内容为原生质体融合,为了提高基因组改组的效率,提高辅酶Q10的产量,本研究对产辅酶Q10的类球红细菌原生质体制备及再生条件进行了优化,通过生长曲线、正交试验等确定了原生质体制备及再生的适宜条件:溶菌酶浓度1 mg/mL、作用温度37℃、作用时间1h以及再生培养基蔗糖浓度10%.在此条件下,类球红细菌原生质体形成率可达到96.1%,再生率可达到28.8%.这为进一步对该菌的基因组改组研究奠定了基础.

  1. Introduction of new carotenoids into the bacterial photosynthetic apparatus by combining the carotenoid biosynthetic pathways of Erwinia herbicola and Rhodobacter sphaeroides.

    OpenAIRE

    Hunter, C N; Hundle, B S; Hearst, J E; Lang, H.P.; Gardiner, A.T.; Takaichi, S; Cogdell, R. J.

    1994-01-01

    Carotenoids have two major functions in bacterial photosynthesis, photoprotection and accessory light harvesting. The genes encoding many carotenoid biosynthetic pathways have now been mapped and cloned in several different species, and the availability of cloned genes which encode the biosynthesis of carotenoids not found in the photosynthetic genus Rhodobacter opens up the possibility of introducing a wider range of foreign carotenoids into the bacterial photosynthetic apparatus than would ...

  2. Genome Shuffling of Rhodobacter Sphaeroides to Improve Coenzyme Q10 Production%利用基因组改组技术提高辅酶Q10产量

    Institute of Scientific and Technical Information of China (English)

    宋丽雅; 乔志新; 李伟静; 贺敏; 于群

    2012-01-01

    Coenzyme Q10 (CoQ10 ) is an important electron transfer molecule in the respiratory chain and the indispensable coenzyme in the production of ATP, and it is widely used in therapeutic applications for several diseases such as heart diseases, hepatitis, Parkinson and so on. In order to improve the production of CoQ10, this paper studies the screening of the mutant Rhodobacter sphaeroides aiming for a higher CoQ10 production by genome shuffling. According to the biosynthetic pathway and its mechanism, various resistance markers are selected, including the roxithromycin, the kanamycin, the p-hydroxy benzcic acid, the vitamin K3 and sodium sulfide (Na2S). Their concentrations are determined according to the tolerance experiments on Rhodobacter sphaeroides. The improved starting population including nine mutant strains is generated by different resistance markers and different mutagenesis ways, such as the ultraviolet irradiation, the ultraviolet/lithium chloride, the diethyl sulfate, the microwave radiation and the y Co60. Several high CoQ10-producing colonies, including PN13, are selected from the first shuffled library. The CoQ10 content of the PN13 reaches 2.39mg/g, 2.52 times of that of the wild-type strain.%辅酶Q10(CoQ10)是生物细胞呼吸链中的重要递氢体,已广泛应用于心脏病、肝炎、帕金森症等多种疾病的治疗中.为了提高微生物法生产CoQ10的产量,本文利用基因组改组技术选育类球红细菌辅酶Q10高产菌株.根据CoQ10的合成途径及作用机理,确定了不同的抗性筛选标记物:罗红霉素、卡那霉素、对羟基苯甲酸、维生素K3和硫化钠.根据类球红细菌对标记物的耐受性确定了抗性筛选浓度.通过紫外线、紫外线/氯化锂、硫酸二乙酯、微波及钴60 5种诱变方式以及抗性培养基筛选获得了9株改良的突变株作为出发菌株.通过一轮基因组改组得到了几株高产菌株,其中PN13产CoQ10的量可达到2.39mg/g,是原菌的252倍.

  3. Optimization of fermentation conditions for carotenoids production by Rhodobacter sphaeroides%类球红细菌发酵生产类胡萝卜素条件优化

    Institute of Scientific and Technical Information of China (English)

    孔丽娜; 李祖明; 高兆兰; 杨卫东; 王栋; 白志辉

    2015-01-01

    Fermentation medium and cultural conditions were optimized for the production of carotenoids by Rhodobacter sphaeroides 3757 . The results showed that the optimized fermentation medium contained (%):glucose 2 . 0 ,sodium malate 0. 5,yeast extract 1. 3,ammonium sulfate 0. 9,K2 HPO4 0. 09,KH2 PO4 0. 06,vitamin solution 1% and pH 8. 0. The vitamin solution contained (%):VB1 0. 1,nicotinamide (VPP)0. 1,and biotin 0. 0016. After inoculated with 5%of a 24-h-old inoculum culture and incubated at 32 ℃ for 40 h at 200 r/min,the yield of carotenoids was increased by 76. 2% in contrast with that of its initial fermentation conditions.%本文对类球红细菌3757产类胡萝卜素进行了发酵条件优化,结果得到了较优的培养基组成:葡萄糖2%,苹果酸钠0.5%,酵母浸粉1.3%,硫酸铵0.9%,磷酸氢二钾0.09%,磷酸二氢钾0 .06%,生长因子溶液1%,pH 8 .0;其中,生长因子溶液配方:维生素 B10.1%,烟酰胺(VPP )0.1%,生物素0.0016%。较优培养条件为:接种量5%,转速200 r/min,种龄24 h,发酵温度32℃,发酵时间40 h。优化后类胡萝卜素产率较优化前提高了76.2%。

  4. Kinetics of cytochrome c oxidase from R. sphaeroides initiated by direct electron transfer followed by tr-SEIRAS.

    Science.gov (United States)

    Steininger, Christoph; Reiner-Rozman, Ciril; Schwaighofer, Andreas; Knoll, Wolfgang; Naumann, Renate L C

    2016-12-01

    Time-resolved surface-enhanced IR-absorption spectroscopy (tr-SEIRAS) has been performed on cytochrome c oxidase from Rhodobacter sphaeroides. The enzyme was converted electrochemically into the fully reduced state. Thereafter, in the presence of oxygen, the potential was switched to open circuit potential (OCP). Under these conditions, the enzyme is free to undergo enzymatic oxidation in the absence of an external electric field. Tr-SEIRAS was performed using the step-scan technique, triggered by periodic potential pulses switching between - 800mV and OCP. Single bands were resolved in a broad band in the amide I region using phase sensitive detection. Amplitudes of these bands were analyzed as a function of time. Time constants in the ms time scale were considered in terms of conformational changes of the protein secondary structures associated with the enzymatic turnover of the protein. PMID:27398977

  5. Complete Genome Sequences of Five Bacteriophages That Infect Rhodobacter capsulatus.

    Science.gov (United States)

    Bollivar, David W; Bernardoni, Brooke; Bockman, Matthew R; Miller, Brenda M; Russell, Daniel A; Delesalle, Veronique A; Krukonis, Gregory P; Hatfull, Graham F; Cross, Madeline R; Szewczyk, Marlena M; Eppurath, Atul

    2016-05-26

    Five bacteriophages that infect the Rhodobacter capsulatus strain YW1 were isolated from stream water near Bloomington, Illinois, USA. Two distinct genome types are represented in the newly isolated bacteriophages. These genomes are different from other bacteriophage genomes previously described.

  6. Selective isolation of UV-sensitive Rhodopseudomonas sphaeroides mutants

    International Nuclear Information System (INIS)

    Application of penicillin selection method after UV irradiation (λ=254 nm) increases by an order efficiency of mutant selection sensible to ulraviolet radiation (uvs mutants), phototrophic bacterium Rhodopseudomonas sphaeroides induced with nitrosomethylurea (NMM). Over 30% of uvs mutants produced by means of this method possessed increased sensitivity not only to short-wave (sUV, λ=254 nm) but also to long-wave (lUV, λ>280 nm) UV radiations. No correlation in the degree of sensitivity of uvs mutants to sUV and lUV irradiations is discovered. Mutants, which are high-sensitive to lethal effect of lUV, are separated

  7. Rhodobacter sediminis sp. nov., isolated from lagoon sediments.

    Science.gov (United States)

    Subhash, Y; Lee, Sang-Seob

    2016-08-01

    Two Gram-stain-negative, rod-shaped phototrophic bacteria (designated strains N1T and C7) were isolated from lagoon sediments. Both strains were positive for catalase and oxidase activity. Casein, starch, urea and Tween 20 were hydrolysed by both strains while chitin, gelatin and Tween 80 were not. In both strains, C16 : 0, C18 : 0,C16 : 1ω6c/C16 : 1ω7c and C18 : 1ω6c/ C18 : 1ω7c were the predominant fatty acids, with minor amounts of C8 : 0 3-OH, anteiso-C14 : 0, C17 : 0, C14 : 1ω5c, C17 : 1 10-methyl and C18 : 1ω5c. Strains N1T and C7 contained phosphatidylglycerol and phosphatidylethanolamine as major polar lipids with minor amounts of phosphatidylcholine, unidentified lipids and an unidentified phospholipid. The mean genomic DNA G+C content was 70.6±1 mol% and the two strains were closely related (mean DNA-DNA hybridization >90 %). Phylogenetic analysis based on 16S rRNA gene sequences showed that the two strains clustered with species of the genus Rhodobacter belonging to the family Rhodobacteraceae of the class Alphaproteobacteria. Strain N1T has a 16S rRNA gene sequence similarity of 99.2 % with Rhodobacter capsulatus ATCC 11166T, 99.1 % with Rhodobacter viridis JA737T and <96.6 % with other members of the genus Rhodobacter. Strain N1T and C7 shared 100 % 16S rRNA gene sequence similarity. DNA- DNA hybridization values between strain N1T and the type strains of the nearest species were clearly below the 70 % threshold. On the basis of phenotypic and genotypic data, it is proposed that strain N1T represents a novel species of the genus Rhodobacter, for which the name Rhodobacter sediminis sp. nov. is proposed. The type strain is N1T (=KEMB 563-471T=JCM 31175T), and strain C7 is an additional strain of the species. PMID:27150292

  8. DU COTÉ DE CHEZ SOI

    Directory of Open Access Journals (Sweden)

    Marc Smeets

    2013-12-01

    Full Text Available Le voyage en Hollande, au XIXe siècle, s'inscrit dans une longue tradition où résonnent les notions de liberté, tolérance et commerce, mais il acquiert aussi une spécificité étant donné l’importance que prend la figure du « chez soi » : les Pays-Bas, terre d'agrément où le voyageur français se sent à l'aise et où il aimerait, si possible, vivre. Proust, de ce point de vue-là, ne fait rien de neuf quand il rêve dans la Recherche d'une « vie domestique » en terre batave. Les Pays-Bas, pour le voyageur français au XIXe, c'est le home sweet home.

  9. Blaulichtabhängige Genregulation in Rhodobacter sphaeroides : Untersuchungen zur physiologischen Funktion der Blaulichtphotorezeptoren AppA, CryB und LOV

    OpenAIRE

    Metz, Sebastian

    2010-01-01

    Licht stellt einen bedeutenden Umweltfaktor der Photosynthesegenregulation von phototropen Organismen dar. Da es neben seiner Funktion als Energieträger auch schädlichen Einfluss haben kann, müssen phototrophe Organismen Mechanismen entwickeln, um vorhandene Lichtreize in eine Genantwort umzusetzen. Blaulichtrezeptoren stellen dabei die häufigsten Proteine zur Lichtwahrnehmung in Prokaryoten dar und erlauben es ihnen, ihre Genantwort an die Bedingungen der Außenwelt anzupassen. In R. spha...

  10. Les pathologies parodentales chez l'enfant

    OpenAIRE

    CHOHRAOUI, Souaad; BASSAID, Nabila

    2012-01-01

    Comme l'enfant qui est n pleine croissance, son parodonte, lui aussi, s'adapte à toutes les variations physiologiques. Ce constant remaniement laisse apparaître des zones de plus grande s isceptibilité parodontale, comme des phénomènes inflammatoires pouvant êtrI physiologiques et/ou pathologiques. D'où la grande difficulté à pouvoir diagnosti uer une parodontite agressive chez le sujet jeune. Pour établir un tel dia g ostic, l'anamnèse, l'examen clinique, radiographique et ...

  11. MNINGE CHEZ LE NOURRISSON ET LENFANT

    OpenAIRE

    Larbaoui, Ismail; Mali, Mokhtar

    2010-01-01

    Au terme de cette étude la méningite reste parmis les maladies infectieuses les plus fréquentes chez l'enfant vue la diversite des germes en cause et l'absense d'une stratégie prophylactique adéquate .d'ou l'intéret d'élargir le programme national de vaccination en introduisant des nouveaux vaccins telque l'antihaemophilusA antiméningoccoque Le diagnostic positif repose éssentiellement sur les données de la ponction lombaire surtout la cytobiochimie du LCR vue la non disponi...

  12. Energy Coupling of Facilitated Transport of Inorganic Ions in Rhodopseudomonas sphaeroides

    NARCIS (Netherlands)

    Hellingwerf, K; Friedberg, Ilan; Lolkema, Juke S.; Michels, Paul A.M.; Konings, Wilhelmus

    1982-01-01

    Within the scope of a study on the effects of changes in medium composition on the proton motive force in Rhodopseudomonas sphaeroides, the energy coupling of sodium, phosphate, and potassium (rubidium) transport was investigated. Sodium was transported via an electroneutral exchange system against

  13. Analysis of the puc Operon Promoter from Rhodobacter capsulatus

    Science.gov (United States)

    Nickens, David G.; Bauer, Carl E.

    1998-01-01

    Expression of the Rhodobacter capsulatus puc operon, which codes for structural polypeptides of the light-harvesting-II peripheral antenna complex, is highly regulated in response to alterations in oxygen tension and light intensity. To obtain an understanding of the puc promoter region we report the high-resolution 5′ mapping of the puc mRNA transcriptional start site and DNA sequence analysis of the puc upstream regulatory sequence (pucURS). A ς70-type promoter sequence was identified (pucP1) which has a high degree of sequence similarity with carotenoid and bacteriochlorophyll biosynthesis promoters. Inspection of the DNA sequence also indicated the presence of two CrtJ and four integration host factor (IHF) binding sites. Transcriptional fusions of the pucURS fused to lacZ also confirmed that puc promoter activity is regulated by the transcriptional regulators IHF, CrtJ, and RegA. Gel retardation analysis using cell extracts indicates that mutations in IHF and RegA disrupt protein binding to DNA fragments containing the pucURS. PMID:9696778

  14. Heat modifiability and detergent solubility of outer membrane proteins of Rhodopseudomonas sphaeroides.

    OpenAIRE

    Kent, N E; Wisnieski, B J

    1983-01-01

    The outer membrane fraction from Rhodopseudomonas sphaeroides was isolated by isopycnic density centrifugation. The purity of this fraction was assayed by several methods. When the outer membrane fraction obtained after French press lysis of cells was compared with the outer membrane fragments released during spheroplast formation, the polypeptide profiles were identical. Detergent solubilization of membrane fractions showed that Triton X-100 nonselectively solubilizes both the cytoplasmic me...

  15. RsaI: a new sequence-specific endonuclease activity from Rhodopseudomonas sphaeroides.

    OpenAIRE

    Lynn, S P; Cohen, L K; Kaplan, S; Gardner, J F

    1980-01-01

    A new type II sequence-specific endonuclease, RsaI, has been identified from Rhodopseudomonas sphaeroides strain 28/5. An RsaI purification scheme that yields enzyme which is free of contaminating exonuclease and phosphatase activities after a single column fractionation has been developed. The enzyme recognized the tetranucleotide sequence 5'-GTAC-3' and cleaved between the T and A, thereby generating flush ends. RsaI should be extremely useful in deoxyribonucleic acid sequencing experiments.

  16. Nostoc sphaeroides Kützing, an excellent candidate producer for CELSS

    Science.gov (United States)

    Hao, Zongjie; Li, Dunhai; Li, Yanhui; Wang, Zhicong; Xiao, Yuan; Wang, Gaohong; Liu, Yongding; Hu, Chunxiang; Liu, Qifang

    2011-11-01

    Some phytoplankton can be regarded as possible candidates in the establishment of Controlled Ecological Life Support System (CELSS) for some intrinsic characteristics, the first characteristic is that they should grow rapidly, secondly, they should be able to endure some stress factors and develop some corresponding adaptive strategies; also it is very important that they could provide food rich in nutritious protein and vitamins for the crew; the last but not the least is they can also fulfill the other main functions of CELSS, including supplying oxygen, removing carbon dioxide and recycling the metabolic waste. According to these characteristics, Nostoc sphaeroides, a potential healthy food in China, was selected as the potential producer in CELSS. It was found that the oxygen average evolution rate of this algae is about 150 μmol O 2 mg -1 h -1, and the size of them are ranged from 2 to 20 mm. Also it can be cultured with high population density, which indicated that the potential productivity of Nostoc sphaeroides is higher than other algae in limited volume. We measured the nutrient contents of the cyanobacterium and concluded it was a good food for the crew. Based on above advantages, Nostoc sphaeroides was assumed to a suitable phytoplankton for the establishment of Controlled Ecological Life Support System. We plan to develop suitable bioreactor with the cyanobacterium for supplying oxygen and food in future space missions.

  17. Colony development and physiological characterization of the edible blue-green alga, Nostoc sphaeroides (Nostocaceae, Cyanophyta)

    Institute of Scientific and Technical Information of China (English)

    Zhongyang Deng; Qiang Hu; Fan Lu; Guoxiang Liu; Zhengyu Hu

    2008-01-01

    The edible blue-green alga,Nostoc sphaeroides Kützing,is able to form microcolorties and spherical macrocolonies.It has been used as a potent herbal medicine and dietary supplement for centuries because of its nutraceutical and pharmacological benefits.However,lim-ited information is available on the development of the spherical macrocolonies and the environmental factors that affect their structure.This report described the morphogenesis of N.Sphaeroides from single trichomes to macrocolonies.During the process,most structural features of macrocolonies of various sizes were dense maculas,rings,the compact core and the formation of liquid core;and the filaments within the macrocolonies showed different lengths and arrays depending on the sizes of macrocolonies.Meanwhile temperature and light intensity also strongly affected the internal structure of macrocolonies.As microcolonies further increased in size to form 30 mm mac-rocolonies,the colonies differentiated into distinct outer,middle and inner layers.The filaments of the outer layer showed higher max-imum photosynthetic rates,higher light saturation point,and higher photosynthetic efficiency than those of the inner layer;whereas the filaments of the inner layer had a higher content of chlorophyll a and phycobiliproteins than those of the outer layer.The results obtained in this study were important for the mass cultivation of N.Sphaeroides as a nutraceutical product.

  18. Cloning and characterization of the gene product of the form II ribulose-1,5-bisphosphate carboxylase gene of Rhodopseudomonas sphaeroides.

    OpenAIRE

    Muller, E D; Chory, J; Kaplan, S

    1985-01-01

    We report the cloning and characterization of the gene product of the gene for the form II ribulose bisphosphate carboxylase from Rhodopseudomonas sphaeroides. We present evidence that the form II enzyme is encoded by a single gene in R. sphaeroides; however, this gene does hybridize to a second chromosomal locus.

  19. 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

  20. Inactivation of Mg Chelatase during Transition from Anaerobic to Aerobic Growth in Rhodobacter capsulatus

    OpenAIRE

    Willows, Robert D; Lake, Vanessa; Roberts, Thomas Hugh; Beale, Samuel I.

    2003-01-01

    The facultative photosynthetic bacterium Rhodobacter capsulatus can adapt from an anaerobic photosynthetic mode of growth to aerobic heterotrophic metabolism. As this adaptation occurs, the cells must rapidly halt bacteriochlorophyll synthesis to prevent phototoxic tetrapyrroles from accumulating, while still allowing heme synthesis to continue. A likely control point is Mg chelatase, the enzyme that diverts protoporphyrin IX from heme biosynthesis toward the bacteriochlorophyll biosynthetic ...

  1. 葛仙米表层结构的扫描电子显微镜观察%Obsevation for Epidermal Ultrastructure of Nostoc sphaeroides Kutzing under Scanning Electron Microscope

    Institute of Scientific and Technical Information of China (English)

    李莉

    2009-01-01

    [Objective]The experiment aimed to explore a new way for observing surface structure of Nostoc sphaeroides Kutzing. [Method] The scanning electron microscope was used to observe the epidermal ultrastructure of wild and cultured Nostoc sphaeroides Kutzing. [Result] The epidermis of wild and cultured Nostoc sphaeroides Kutzing showed mixture structure of fibril colloid which was reticular arranged. The difference between wild and cultured Nostoc sphaeroides Kutzing was that the outer epidermis of cultured Nostoc sphaeroides Kutzing had trichome distribution but the wild Nostoc sphaeroides Kutzing did not has such distribution. The obsevation results of under smaller than 10 μm by scanning electron microscope was touched thick and showed many folds and distortions.[Conclusion] The scanning electron microscope was an effective way to study development of Nostoc sphaeroides Kutzing colony and it was worth popularizing.

  2. La formation du comportement de plainte chez le consommateur: recherche exploratoire chez des usagers de restaurants

    OpenAIRE

    Moliner Velázquez, Beatriz; Berenguer Contrí, Gloria; Gil Saura, Irene

    2011-01-01

    Cette recherche aborde le processus de formation du comportement de plainte chez le consommateur. L´objectif général est d´approfondir sur la nature de ce type de réponse à l´insatisfaction, en décrivant sa formation à partir des apports d´un ensemble de variables puisées dans la littérature. En partant du fait que le comportement de plainte englobe trois types de réponses (de plainte, vis à vis des tiers, et privé), nous analysons l´effet provoqué par le niveau d´insatisfaction, la probabili...

  3. Embryonic, Larval, and Early Juvenile Development of the Tropical Sea Urchin, Salmacis sphaeroides (Echinodermata: Echinoidea

    Directory of Open Access Journals (Sweden)

    M. Aminur Rahman

    2012-01-01

    Full Text Available Salmacis sphaeroides (Linnaeus, 1758 is one of the regular echinoids, occuring in the warm Indo-West Pacific, including Johor Straits, between Malaysia and Singapore. In order to investigate the developmental basis of morphological changes in embryos and larvae, we documented the ontogeny of S. sphaeroides in laboratory condition. Gametes were obtained from adult individuals by 0.5 M KCl injection into the coelomic cavity. Fertilization rate at limited sperm concentration (10−5 dilution was 96.6±1.4% and the resulting embryos were reared at 24°C. First cleavage (2-cell, 4-cell, 8-cell, 16-cell, 32-cell, and multicell (Morulla stages were achieved 01.12, 02.03, 02.28, 02.51, 03.12, and 03.32 h postfertilization. Ciliated blastulae with a mean length of 174.72±4.43 μm hatched 08.45 h after sperm entry. The gastrulae formed 16.15 h postfertilization and the archenteron elongated constantly while ectodermal red-pigmented cells migrated synchronously to the apical plate. Pluteus larva started to feed unicellular algae in 2 d, grew continuously, and finally attained metamorphic competence in 35 d after fertilization. Metamorphosis took approximately 1 h 30 min from attachment to the complete resorption of larval tissues and the development of complete juvenile structure with adult spines, extended tubefeet and well-developed pedicellaria, the whole event of which usually took place within 1 d postsettlement. This study represents the first successful investigation on embryonic, larval, and early juvenile development of S. sphaeroides. The findings would greatly be helpful towards the understanding of ontogeny and life-history strategies, which will facilitate us to develop the breeding, seed production, and culture techniques of sea urchins in captive condition.

  4. 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.

  5. Nostoc sphaeroides Kütz, a candidate producer par excellence for CELSS

    Science.gov (United States)

    Wang, Gaohong; Hao, Zongjie; Liu, Yongding

    A lot of aquatic organisms could be regarded as suitable candidates par excellence in the establishment of CELSS, since they are relatively easy and fast to grow and resistant to changes in environmental condition as well as providing nutritious, protein-and vitamin-rich foods for the crew, which can fulfill the main functions of CELSS, including supplying oxygen, water and food, removing carbon dioxide and making daily life waste reusable. Our labotory has developed mass culture of Nostoc sphaeroides Kütz, which is one of traditional healthy food in China and. The oxygen evolution rate of the cyanobacterium is about 150 molO2.mg-1.h-1, and it usually grows into colony with size between 2-20mm, which is easy to be harvested. It also can be cultured with high density, which show that the productivity of the cyanobacterium in limited volume is higher than other microalgae. We had measured the nutrient content of the cyanobacterium and developed some Chinese Dishes and Soups with Nostoc sphaeroides Kütz, which showed that it was a good food for crew. Using remote sensing technique, we also investigated its growth in Closed System under microgravity by SHENZHOU-2 spacecraft in January 2001. We plan to develop suitable bioreactor with the cyanobacterium for supplying oxygen and food to crew in future.

  6. Photoregulated or Energy Dependent Process of Hormogonia Differentiation in Nostoc sphaeroides Kützing (Cyanobacterium)

    Institute of Scientific and Technical Information of China (English)

    Dun-Hai LI; Lan-Zhou CHEN; Gen-Bao LI; Gao-Hong WANG; Li-Rong SONG; Yong-Ding LIU

    2005-01-01

    Hormogonium, which was thought to play an important role in the dispersal and survival of these microorganisms in their natural habitats, is a distinguishable developmental stage of heterocystous cyanobacteria. The present study examined the effects of different light conditions and sugars on the of hormogonia was light dependent in the absence of sugar, but that close to 100% of cyanobacteria differentiated to hormogonia in the presence of glucose or sucrose, irrespective of the light conditions. This differentiation was inhibited, even in the presence of sugars, upon application of an inhibitor of respiration.Following the testing of different sugars, the effects of different lights were examined. It was found that 5-10 μmol.m-2.s-1 photon flux density was optimal for hormogonia differentiation. One hundred percent differentiation was obtained with white light irradiation, in contrast with irradiation with green light (80%differentiation) and red light (0-10% differentiation). Although they showed different efficiencies in induc ing hormogonia differentiation in N. sphaeroides, the green and red radiation did not display antagonistic effects. When the additional aspect of time dependence was investigated through the application of different light radiations and an inhibitor of protein synthesis, it was found that the initial 6 h of the differentiation process was crucial for hormogonia differentiation. Taken together, these results show that hormogonia differentiation in N. sphaeroides is either a photoregulated or an energy dependent process.

  7. BIOREMEDIATION OF SLAUGHTER HOUSE WASTE WATER BY RHODOBACTER SP. GSKRLMBKU-02

    OpenAIRE

    Kadari Rajyalaxmi; Ramchander Merugu; S.Girisham; Reddy SM

    2015-01-01

    Biological treatment of waste waters is a sustainable alternative for waste treatment to existing treatment methods. Microbial metabolism effects pH, BOD, COD, DO and concentration of suspended solids present in slaughter house waste water. Rhodobacter sp. GSKRLMBKU-02 from paper mill waste water was used in the present study to remediate slaughter house waste water. Treatment with this bacterium caused a significant decrease in some of the parameters tested for waste water. Remediation of sl...

  8. Evolution du comportement de manipulation chez les strepsirrhiniens

    OpenAIRE

    Peckre, Louise; Fabre, Anne‑Claire; Herrel, Anthony; Wall, Christine; Pouydebat, Emmanuelle

    2016-01-01

    Les capacités de préhension des catarrhiniens ont été largement étudiées dans le cadre de problématiques cognitives, fonctionnelles et évolutives. Une importante variabilité dans les types de saisies utilisés, incluant des stratégies longtemps décrites comme spécifiques des humains, a ainsi été mise en évidence. Cependant, bien que la préhension soit impliquée dans de nombreuses activités chez tous les primates, elle reste peu étudiée chez les platyrrhiniens et les strepsirrhiniens. Ces derni...

  9. Cloning, characterization, and regulation of nifF from Rhodobacter capsulatus.

    OpenAIRE

    G. de Gennaro; Hübner, P.; Sandmeier, U; Yakunin, A. F.; Hallenbeck, P C

    1996-01-01

    The Rhodobacter capsulatus nifF gene and upstream sequence were cloned by using a probe based on the N-terminal sequence of NifF. nifF was found to not be contained in the previously described nif regions I, II, and III. Comparison of the deduced amino acid sequence showed that it is highly similar to NifF from Azotobacter vinelandii and NifF from Klebsiella pneumoniae. Analysis of translational fusions demonstrated that the regulation of transcription was the same as previously reported at t...

  10. The effect of temperature and light intensity on hydrogen production by Rhodobacter capsulatus

    Energy Technology Data Exchange (ETDEWEB)

    Eroglu, Inci [Middle East Technical Univ., Ankara (Turkey). Dept. of Chemical Engineering; Sevinc, Pelin [Middle East Technical Univ., Ankara (Turkey). Dept. of Biotechnology; Guenduez, Ufuk; Yucel, Meral [Middle East Technical Univ., Ankara (Turkey). Dept. of Biological Sciences

    2010-07-01

    Rhodobacter capsulatus is a purple non-sulfur photosynthetic bacterium which can produce hydrogen by photofermentation on acetate and lactate. Hydrogen productivity depends on several parameters such as medium composition, pH, light intensity and temperature. In the present study, the effects of temperature and light intensity on hydrogen production were investigated. The cell growth curve has been fitted to the logistic model and hydrogen productivity was interpreted by Modified Gompertz Equation. The maximum productivity was obtained at 30 C and light intensity of 4000 lux. (orig.)

  11. Le squelette et sa pathologie chez les reptiles

    OpenAIRE

    Depas, Céline

    2012-01-01

    Les affections squelettiques sont de nature variée chez les reptiles. Elles nécessitent pour les individus une prise en charge adaptée et pour le clinicien une connaissance des particularités de leur squelette. Ce travail est une étude bibliographique divisée en trois parties. Dans un premier temps seront abordées la classification, l’anatomie et la physiologie osseuse des reptiles. Puis sera décrite la conduite à suivre lors d’une consultation, de l’anamnèse aux examens complémentaires. L’an...

  12. l'étude de la mycoflore superficielle chez le diabétique

    OpenAIRE

    Amimer, Leila; Belabbes, Amina

    2014-01-01

    Les mycoses superficielles demeurent une pathologie fréquente en pratique dermatologique en particulier chez les diabétiques où le diabète constituant à la fois un facteur favorisant et aggravant. L'objectif de notre travail était de déterminer la prévalence spécifique des mycoses superficielles chez les diabétiques, d'étudier la mycoflore superficielle chez eux et de rechercher les facteurs favorisants la survenue de ces lésions mycosiques. Nous rapportons une étude transversale ...

  13. L’étude de la mycoflore superficielle chez le diabétique

    OpenAIRE

    Amimer, Leila; Belabbes, Amina

    2014-01-01

    Les mycoses superficielles demeurent une pathologie fréquente en pratique dermatologique en particulier chez les diabétiques où le diabète constituant à la fois un facteur favorisant et aggravant. L’objectif de notre travail était de déterminer la prévalence spécifique des mycoses superficielles chez les diabétiques, d’étudier la mycoflore superficielle chez eux et de rechercher les facteurs favorisants la survenue de ces lésions mycosiques. Nous rapportons une étude transversale descripti...

  14. Conditions Optimization of Ultrasonic Assisted with HCl Extraction of Carotenoid from Rhodobacter sphaeroides%酸溶辅助超声波法提取类球红细菌类胡萝卜素条件优化

    Institute of Scientific and Technical Information of China (English)

    李祖明; 张猛; 张静; 高丽萍; 惠伯棣; 杨卫东; 王栋; 白志辉

    2014-01-01

    通过单因素和正交试验,对类球红细菌3757产类胡萝卜素的提取条件进行了研究.先采用超声波法、酸溶法、研磨法、冻融法、酸溶辅助超声波法和冻融辅助超声波法优化了从类球红细菌3757菌株中提取类胡萝卜紊的方法,然后开展了酸溶辅助超声波法的单因素和正交实验,最后进行了重复性实验.结果表明,酸溶辅助超声波法是较优的提取方法,丙酮是较好的提取溶剂.最佳提取条件为料液比1∶10、超声波处理总时间20 min、酸浓度3 mol/L、酸溶时间25 min、超声波振幅40%、超声工作/间隔时间2 min/1 min、酸溶温度27℃,实验重现较好.优化后类胡萝卜素的提取率较优化前提高了74.8%,为其产业化创造了条件.

  15. Ultrafast excitation relaxation in light-harvesting complex LH2 from Rb. sphaeroides 601

    Institute of Scientific and Technical Information of China (English)

    GUO; Lijun; LIU; Yuan; LIU; Weimin; GUO; Junhua; XU; Chunhe

    2004-01-01

    The energy relaxation and kinetic evolution of transient spectra of bacteriochloro- phylls (BChls) in light-harvesting complex LH2 from Rb. Sphaeroides 601 were investigated using femtosecond pump-probe technique. Upon 783 nm excitation, the energy at B800 BChls experiences an intramolecular redistribution with 0.35 ps time constant before transferring to B850 BChls. With tuning the excitation wavelength, the dynamical evolution of excited BChls was clearly observed, which indicates an obvious competition between the ground state bleaching and excited state absorption (ESA) of BChls involved and an isosbestic point near 818 nm, and also demonstrates that from the lower electronic excited state of B800 BChls to the higher excitonic state of B850 BChls is an efficient routine for energy transfer. The excitation energy in higher excitonic states of B850 BChls relaxes rapidly to the next lowest excitonic state by interconversion, delocalization to adjacent molecular, populating the lowest excitonic state and the change of molecular conformation.

  16. Ultrafast excitation relaxation in light-harvesting complex LH2 from Rb.sphaeroides 601

    Institute of Scientific and Technical Information of China (English)

    GUO Lijun; LIU Yuan; LIU Weimin; GUO Junhua; XU Chunhe; QIAN Shixiong

    2004-01-01

    The energy relaxation and kinetic evolution of transient spectra of bacteriochloro- phylls (BChls) in light-harvesting complex LH2 from Rb. Sphaeroides 601 were investigated using femtosecond pump-probe technique. Upon 783 nm excitation, the energy at B800 BChls experiences an intramolecular redistribution with 0.35 ps time constant before transferring to B850 BChls. With tuning the excitation wavelength, the dynamical evolution of excited BChls was clearly observed, which indicates an obvious competition between the ground state bleaching and excited state absorption (ESA) of BChls involved and an isosbestic point near 818 nm, and also demonstrates that from the lower electronic excited state of B800 BChls to the higher excitonic state of B850 BChls is an efficient routine for energy transfer. The excitation energy in higher excitonic states of B850 BChls relaxes rapidly to the next lowest excitonic state by interconversion, delocalization to adjacent molecular, populating the lowest excitonic state and the change of molecular conformation.

  17. Nature du code phonologique en lecture chez les personnes entendantes et chez les personnes sourdes : de la syllabe aux traits phonétiques

    OpenAIRE

    Bedoin, Nathalie

    2005-01-01

    L'objectif principal de cette recherche est de mieux comprendre la nature du code phonologique participant à la reconnaissance de mot écrit, les unités qu'il implique et ses particularités chez les personnes entendantes et sourdes. Une première série de 8 expériences (amorçage et masquage) nous conduit à décrire ce code phonologique en termes de traits phonétiques chez les entendants : ils sont sensibles à des ressemblances de traits phonétiques entre phonèmes successifs. Nous décrivons des m...

  18. Le cri de la nature chez Terrence Malick

    OpenAIRE

    Barnier, Martin

    2016-01-01

    Après avoir vu The Thin Red Line (La Ligne rouge, 1998), le spectateur se souviendra sûrement des voix des soldats qui se posent délicatement sur les images. Mais la plus grande partie du son de ce film se compose de musique et de bruits. Les oiseaux jouent un rôle prépondérant chez Terrence Malick. Passionné par l’ornithologie, il a souvent cherché à être le plus précis possible sur chacun des chants d’oiseaux qu’il place dans ses films. Lors du tournage de The New World (Le Nouveau monde, 2...

  19. Ostéopathie et troubles gastriques chez le chien

    OpenAIRE

    Agneray, François

    2003-01-01

    L'auteur se propose dans cette étude d'évaluer les possibilités thérapeutiques de l'ostéopathie (ou médecine manuelle) en cas de troubles gastriques chez le chien.Pour cela, il étudiera l'estomac et ses pathologies en insistant sur les points nécessaires à la compréhension du mode d'action de l'ostéopathie sur cet organe. L'ostéopathe, en agissant sur la structure, peut jouer sur la fonction : les troubles à dominante fonctionnelle seront donc traitées par ostéopathie avec le plus de profit, ...

  20. Enhanced photo-fermentative hydrogen production by Rhodobacter capsulatus with pigment content manipulation.

    Science.gov (United States)

    Ma, Chao; Wang, Xueqing; Guo, Liejin; Wu, Xiaomin; Yang, Honghui

    2012-08-01

    High content of pigment in purple nonsulfur photosynthetic bacteria hinders its photo-hydrogen production rate under intense light irradiation. In order to alleviate the light shielding effect and improve its photo-fermentative hydrogen production performance, pufQ, which is the regulatory gene of bacteriochlorophyll biosynthesis in Rhodobacter capsulatus, was cloned and relocated in the genome under cbb3 promoter by homologous recombination. The UV-vis spectra indicated that the light absorption of the mutant between 300 and 900 nm was reduced. Photo-hydrogen production experiments by the recombinant and wild type strain were carried out in 350 mL photo bioreactors using acetic and butyric acid as substrate. The results showed that the hydrogen production of recombinant with reduced pigment was 27% higher than that of its parental strain, indicating that it is effective on enhancing photo-fermentative hydrogen production by manipulating pigment biosynthesis in purple nonsulfur photosynthetic bacteria. PMID:22717568

  1. Replacement of sugars to hydrogen production by Rhodobacter capsulatus using dark fermentation effluent as substrate.

    Science.gov (United States)

    Silva, Felipe Thales Moreira; Moreira, Luiza Rojas; de Souza Ferreira, Juliana; Batista, Fabiana Regina Xavier; Cardoso, Vicelma Luiz

    2016-01-01

    Hydrogen is a promising alternative for the increased global energy demand since it has high energy density and is a clean fuel. The aim of this work was to evaluate the photo-fermentation by Rhodobacter capsulatus, using the dark fermentation effluent as substrate. Different systems were tested by changing the type of sugar in the dark fermentation, investigating the influence of supplementing DFE with sugar and adding alternate and periodically lactose and glucose throughout the process. The supplementation of the DFE with sugar resulted in higher H2 productivity and the replacement of the sugars repeatedly during the photo-fermentation process was important to maintain the cell culture active. By controlling the residual amount of sugar, bacteria inhibition was avoided; lactic acid, that was toxic to the biomass, was consumed and the metabolic route of butyric acid production was predominant. Under optimum conditions, the H2 productivity reached 208.40mmolH2/Ld in 52h. PMID:26476167

  2. Cloning, characterization, and regulation of nifF from Rhodobacter capsulatus.

    Science.gov (United States)

    Gennaro, G; Hübner, P; Sandmeier, U; Yakunin, A F; Hallenbeck, P C

    1996-07-01

    The Rhodobacter capsulatus nifF gene and upstream sequence were cloned by using a probe based on the N-terminal sequence of NifF. nifF was found to not be contained in the previously described nif regions I, II, and III. Comparison of the deduced amino acid sequence showed that it is highly similar to NifF from Azotobacter vinelandii and NifF from Klebsiella pneumoniae. Analysis of translational fusions demonstrated that the regulation of transcription was the same as previously reported at the protein level. Insertional mutagen esis showed that NifF contributes significantly to nitrogenase activity under normal nitrogen-fixing conditions and that it is absolutely required for nitrogen fixation under iron limitation. PMID:8682802

  3. Effect of dietary Rhodobacter capsulatus on egg-yolk cholesterol and laying hen performance.

    Science.gov (United States)

    Salma, U; Miah, A G; Tareq, K M A; Maki, T; Tsujii, H

    2007-04-01

    The present study was conducted to investigate the effects of dietary Rhodobacter capsulatus on the laying hen. A total of forty 23-wk-old Hy-Line Brown laying hens were randomly assigned into 4 treatment groups (10 laying hens/group) and fed diets supplemented with 0 (control), 0.01, 0.02, and 0.04% R. capsulatus during the 60-d feeding period. Dietary supplementation of R. capsulatus (0.04%) reduced (P color was improved (P effects on egg production, shell weight, shell thickness, Haugh unit, yolk index, and feed conversion efficiency compared with the same parameters for the control laying hens. It is postulated that known and unknown factors are present in R. capsulatus presumably responsible for the hypocholesterolemic effect on laying hens. Therefore, the dietary supplementation of R. capsulatus may lead to the development of low-cholesterol chicken eggs as demanded by health-conscious consumers. PMID:17369543

  4. 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.

  5. 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.

  6. The Transmembrane Electrical Potential in Rhodopseudomonas sphaeroides Determined from the Distribution of Tetraphenylphosphonium after Correction for Its Binding to Cell Components

    NARCIS (Netherlands)

    Lolkema, Juke S.; Abbing, Arend; Hellingwerf, K; Konings, Wilhelmus

    1983-01-01

    The membrane potential was determined in intact cells of Rhodopseudomonas sphaeroides from the distribution of the lipophilic cation tetraphenylphosphonium (Ph4P+) after correction for probe binding to cell components. The concentration of Ph4P+ in the external medium of the cells was recorded with

  7. La maladie de Wilson chez l'enfant: à propos de 20 cas

    Science.gov (United States)

    Idrissi, Mounia Lakhdar; Babakhoya, Abdeladim; Khabbache, Kawtar; Souilmi, Fatimzohra; Benmiloud, Sara; Abourrazak, Sanae; Chaouki, Sanae; Atmani, Samir; Bouharrou, Abdelhak; Hida, Moustapha

    2013-01-01

    La maladie de Wilson ou dégénérescence hépato-lenticulaire est une affection génétique autosomique récessive caractérisée par une accumulation toxique de cuivre dans l'organisme, essentiellement dans le foie, le système nerveux central et la cornée. L'objectif de ce travail était de soulever les difficultés diagnostiques et thérapeutiques dans la prise en charge de la maladie de Wilson dans notre contexte. Nous avons réalisé une étude rétrospective portant sur 20 cas de maladie de Wilson colligés au sein du service de pédiatrie du CHU HASSAN II de Fès sur une période de 7 ans et demi. Il s'agit de 13 garçons et 7 filles dont l’âge moyen est de 9 ans avec des extrêmes allant de 5 à 13 ans. La consanguinité est retrouvée chez 13 malades. Sur le plan clinique, l'ictère est noté dans 13 cas, un syndrome oedémateux est retrouvé dans 13 cas aussi et un syndrome hémorragique dans 6 cas. Les signes neurologiques sont présents dans 7cas. Trois enfants étaient asymptomatiques diagnostiqués à l'occasion d'un dépistage. Sur le plan biologique les signes d'insuffisance hépatocellulaire sont retrouvés chez 17 malades avec une cytolyse dans 8 cas. Une anémie hémolytique est retrouvée chez 8 malades (soit 40%). La céruléoplasminémie est abaissée chez 17 malades, la cuprurie réalisée chez 19 malades s'est révélée augmentée chez 17 soit 89,4%. L'anneau de Kayser- Fleischer est retrouvé chez 14 patients. L’échographie abdominale a montré des signes d'hypertension portale (HTP) sur foie de cirrhose chez 16 malades soit 80%. La D pénicillamine est instaurée chez 17 patients et trois sont mis sous sulfate de zinc. Trois malades ont bénéficié de la vitamine B6. L’évolution est favorable chez 11 malades avec un recul moyen de 3 ans. Nous déplorons 4 décès chez des malades ayant consulté au stade de cirrhose décompensé. Le pronostic de la maladie de Wilson dépend de la précocité du traitement. Le dépistage chez

  8. La Fécondation In Vitro chez les primates non-humains : Exemple du Papio anubis

    OpenAIRE

    Lacoste, Romain

    2014-01-01

    Les techniques de procréation médicalement assistée (PMA), contrairement à d'autres domaines, se sont d'abord développées chez l'Homme puis ont été transposées chez les primates non-humains (PNH). Les premières tentatives de Fécondation In Vitro (FIV) et d'insémination artificielle (IA) chez les PNH datent des années 70-80. Un bilan succinct des tentatives et réussites dans ce domaine concernant les grands singes et les espèces de primates modèles en expérimentation animale seront présentées....

  9. Multiplication vegetative et conservation in vitro chez le poireau (Allium porrum L.)

    OpenAIRE

    Dore, Claire

    1988-01-01

    La multiplication végétative est nécessaire pour répondre à des objectifs de production de semences chez plusieurs Allium cultivés. Le clonage in vitro apporte une solution intéressante mais l’effectif obtenu à partir de la plante mère est insuffisant. La méthode de multiplication par cycles successifs mise au point chez le poireau consiste à stimuler l’activité les méristèmes latents du plateau basal des plantules. La conservation in vitro permet de différer le repiquage en terre jusqu’...

  10. Le clonage somatique : un état des lieux chez les bovins et les petits ruminants

    OpenAIRE

    Heyman, Yvan; Chavatte-Palmer, Pascale; Vignon, Xavier; Richard, Christophe; Renard, Jean Paul

    2005-01-01

    Parmi les récentes biotechnologies de la reproduction chez les mammifères d’élevage, le clonage par transfert de noyaux somatiques constitue un pas en avant depuis la naissance de la brebis Dolly. Cet article fait le point sur les résultats actuels obtenus dans le monde chez les bovins et les petits ruminants, les limites de la technique et les applications potentielles. L’efficacité globale du clonage (nombre de jeunes nés /nombre d’embryons reconstitués) reste encore faible (≤ 7 %), mais el...

  11. Le cavernome porte chez l'enfant: a propos de 11 cas

    Science.gov (United States)

    Ilham, Tadmori; Mounia, Lakhdar Idrissi; Moustapha, Hida

    2014-01-01

    Le cavernome portal est la conséquence d'une occlusion chronique, du système porte extra-hépatique formé d'un réseau de veines dont le calibre est augmenté et au sein desquelles chemine un sang portal hépatopéte. Chez l'enfant, est une cause majeure d'hypertension portale dite «pré ou infra-hépatique» ou encore «extra-hépatique». Onze cas de cavernome porte parmi 78 cas d'hypertension portale ont été colligés au service sur une période allant du Janvier 2003 au Septembre 2012. L’âge de nos patients variait entre 2 et 15 ans et le sexe ratio est de 1,75. Tous nos patients étaient admis au stade d'hypertension portale avec la splénomégalie SMG (100% des cas); hémorragies digestives (63%); ascite (36%); la circulation veineuse collatérale CVC et l'hépatomégalie HMG (27%). L'exploration endoscopique a objectivé la présence de varices ‘sophagiennes dans tous les cas avec une gastropathie hypertensive dans 27% et des varices ectopiques chez 36%. Les perturbations biologiques étaient dominées par la pancytopénie. Le bilan de thrombophilie était demandé pour tous les malades mais réalisé mais n'est réalisé que chez trois revenus normaux chez deux et a objectivé une baisse de protéine S chez le troisième. L’échographie abdominale était le moyen de diagnostic positif et l’écho-doppler a confirmé l'HTP chez tous nos patients. Aucun de nos malades n'a pu être opéré pour le moment. La ligature a été réalisée chez 54,5%. Dix patients ont nécessité une transfusion sanguine. L’évolution globale de nos patients est favorable. La durée moyenne d’évolution du cavernome porte chez nos patients est de quatre ans. PMID:25870732

  12. 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.

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

    International Nuclear Information System (INIS)

    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 P41212, with unit-cell parameters a = b = 66.49, c = 121.32 Å. X-ray data sets have been collected to 2.17 Å resolution

  14. Dynamics of Antagonistic Potency of Rhodobacter capsulatus PG Lipopolysaccharide against Endotoxin-Induced Effects.

    Science.gov (United States)

    Kabanov, D S; Serov, D A; Zubova, S V; Grachev, S V; Prokhorenko, I R

    2016-03-01

    The dynamics of antagonistic potency of lipopolysaccharide (LPS) isolated from Rhodobacter capsulatus PG on the synthesis of proinflammatory (TNF-α, IL-1β, IL-8, IL-6, IFN-γ) and antiinflammatory (IL-10, IL-1Ra) cytokines induced by highly stimulatory endotoxins from Escherichia coli or Salmonella enterica have been studied. Using human whole blood, we have shown that R. capsulatus PG LPS inhibited most pronouncedly the endotoxin-induced synthesis of TNF-α, IL-1β, IL-8, and IL-6 during the first 6 h after endotoxin challenge. Similarly, the endotoxin-induced release of IFN-γ was abolished by R. capsulatus PG LPS as well (24 h). In contrast to the above-mentioned cytokines, the relatively weak antagonistic activity of R. capsulatus PG LPS against endotoxin-triggered production of IL-6 and IL-8 was revealed. Since R. capsulatus PG LPS displays more potent antagonistic activity against deleterious effects of S. enterica LPS than those of E. coli LPS in the cases of such cytokines as IL-1β (6 and 24 h), IL-6 and IL-8 (4 h), we conclude that the effectiveness of protective action of antagonist is mostly determined by the primary lipid A structure of the employed agonist.

  15. Stark effect in wild-type and heterodimer-containing reaction centers from Rhodobacter capsulatus

    International Nuclear Information System (INIS)

    The effect of an external electric field on the optical absorption spectra of wild-type Rhodobacter capsulatus and two Rb. capsulatus reaction centers that have been genetically modified through site-directed mutagenesis was measured at 77 K. The two genetically modified reaction centers replace histidine M200, the axial ligand to the M-side bacteriochlorophyll of the special pair, with either leucine or phenylalanine. These substitutions results in the replacement of the M-side bacteriochlorophyll with bacteriopheophytin, forming a bacteriochlorophyll-bacteriopheophytin heterodimer. The magnitude of the change in dipole moment from the ground to excited state (Δμapp) and the angle δ between the Qy transition moment and the direction of Δμapp were measured for the special pair absorption band for all three reaction centers. The differences in the magnitude of Δμapp and the angle δ between wild-type and heterodimer reaction centers are consistent with increased charge transfer in the heterodimer special pair. These results support calculations that place the special pair charge-transfer state higher in energy than the excited singlet state in wild-type Rb. capsulatus RCs

  16. 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.)

  17. Two distinct ferredoxins from Rhodobacter capsulatus: complete amino acid sequences and molecular evolution.

    Science.gov (United States)

    Saeki, K; Suetsugu, Y; Yao, Y; Horio, T; Marrs, B L; Matsubara, H

    1990-09-01

    Two distinct ferredoxins were purified from Rhodobacter capsulatus SB1003. Their complete amino acid sequences were determined by a combination of protease digestion, BrCN cleavage and Edman degradation. Ferredoxins I and II were composed of 64 and 111 amino acids, respectively, with molecular weights of 6,728 and 12,549 excluding iron and sulfur atoms. Both contained two Cys clusters in their amino acid sequences. The first cluster of ferredoxin I and the second cluster of ferredoxin II had a sequence, CxxCxxCxxxCP, in common with the ferredoxins found in Clostridia. The second cluster of ferredoxin I had a sequence, CxxCxxxxxxxxCxxxCM, with extra amino acids between the second and third Cys, which has been reported for other photosynthetic bacterial ferredoxins and putative ferredoxins (nif-gene products) from nitrogen-fixing bacteria, and with a unique occurrence of Met. The first cluster of ferredoxin II had a CxxCxxxxCxxxCP sequence, with two additional amino acids between the second and third Cys, a characteristics feature of Azotobacter-[3Fe-4S] [4Fe-4S]-ferredoxin. Ferredoxin II was also similar to Azotobacter-type ferredoxins with an extended carboxyl (C-) terminal sequence compared to the common Clostridium-type. The evolutionary relationship of the two together with a putative one recently found to be encoded in nifENXQ region in this bacterium [Moreno-Vivian et al. (1989) J. Bacteriol. 171, 2591-2598] is discussed. PMID:2277040

  18. 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.

  19. Transcriptional Profiling of Hydrogen Production Metabolism of Rhodobacter capsulatus under Temperature Stress by Microarray Analysis

    Directory of Open Access Journals (Sweden)

    Muazzez Gürgan

    2015-06-01

    Full Text Available Biohydrogen is a clean and renewable form of hydrogen, which can be produced by photosynthetic bacteria in outdoor large-scale photobioreactors using sunlight. In this study, the transcriptional response of Rhodobacter capsulatus to cold (4 °C and heat (42 °C stress was studied using microarrays. Bacteria were grown in 30/2 acetate/glutamate medium at 30 °C for 48 h under continuous illumination. Then, cold and heat stresses were applied for two and six hours. Growth and hydrogen production were impaired under both stress conditions. Microarray chips for R. capsulatus were custom designed by Affymetrix (GeneChip®. TR_RCH2a520699F. The numbers of significantly changed genes were 328 and 293 out of 3685 genes under cold and heat stress, respectively. Our results indicate that temperature stress greatly affects the hydrogen production metabolisms of R. capsulatus. Specifically, the expression of genes that participate in nitrogen metabolism, photosynthesis and the electron transport system were induced by cold stress, while decreased by heat stress. Heat stress also resulted in down regulation of genes related to cell envelope, transporter and binding proteins. Transcriptome analysis and physiological results were consistent with each other. The results presented here may aid clarification of the genetic mechanisms for hydrogen production in purple non-sulfur (PNS bacteria under temperature stress.

  20. Allosteric regulation of the state of adenylylation of glutamine synthetase in permeabilized cell preparations of Rhodopseudomonas sphaeroides.

    Science.gov (United States)

    Wang, X; Song, H Y

    1989-08-01

    Following a freeze-thaw cycle, and the treatment of Rhodopseudomonas sphaeroides with the nonionic detergent Lubrol PX, the permeabilized cell suspensions can be assayed directly both for the intracellular levels of glutamine synthetase and the state of adenylylation (i.e. the average number n of adenylylated subunits/dodecameric molecules). It seems that all components of the bicycle system are retained if cells grown with low concentrations of ammonia as the sole nitrogen source are used. The value of n was dependent upon the concentration of substrates (ATP, Pi) and allosteric effectors (ATP, glutamine and alpha-ketoglutarate) of adenylytransferase. The value of n affected by UTP, the specific substrate of the uridylyltransferase shows first the evidence that the bicycle cascade control system studied in Escherichia coli may exist in this phototrophic bacterium. PMID:2575389

  1. 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.

  2. Contribution à la description anatomique du phytomère chez le genre Pistacia de la wilaya de Tlemcen

    OpenAIRE

    BELKHODJA, Yacine Karim

    2015-01-01

    Contribution à la description anatomique du phytomère chez le genre Pistacia de la wilaya de Tlemcen. Le pétiole des pistachiers étudiés présente un arrangement tissulaire composé de l'extérieur vers l'intérieur de la cuticule, de l'épiderme, de Collenchyme, de parenchyme cortical, de sclérenchyme, de phloème et du xylème. La feuille présente des stomates de type Paratétracytique chez Pistacia atiantica et pistachia vera et de type Anisocytique chez pistacia terebinthus. L'o...

  3. Urea Utilization in the Phototrophic Bacterium Rhodobacter capsulatus Is Regulated by the Transcriptional Activator NtrC

    OpenAIRE

    Masepohl, Bernd; Kaiser, Björn; Isakovic, Nazila; Richard, Cynthia L.; Kranz, Robert G.; Klipp, Werner

    2001-01-01

    The phototrophic nonsulfur purple bacterium Rhodobacter capsulatus can use urea as a sole source of nitrogen. Three transposon Tn5-induced mutations (Xan-9, Xan-10, and Xan-19), which led to a Ure− phenotype, were mapped to the ureF and ureC genes, whereas two other Tn5 insertions (Xan-20 and Xan-22) were located within the ntrC and ntrB genes, respectively. As in Klebsiella aerogenes and other bacteria, the genes encoding urease (ureABC) and the genes required for assembly of the nickel meta...

  4. Coordinated, long-range, solid substrate movement of the purple photosynthetic bacterium Rhodobacter capsulatus.

    Directory of Open Access Journals (Sweden)

    Kristopher John Shelswell

    Full Text Available The long-range movement of Rhodobacter capsulatus cells in the glass-agar interstitial region of borosilicate Petri plates was found to be due to a subset of the cells inoculated into plates. The macroscopic appearance of plates indicated that a small group of cells moved in a coordinated manner to form a visible satellite cluster of cells. Satellite clusters were initially separated from the point of inoculation by the absence of visible cell density, but after 20 to 24 hours this space was colonized by cells apparently shed from a group of cells moving away from the point of inoculation. Cell movements consisted of flagellum-independent and flagellum-dependent motility contributions. Flagellum-independent movement occurred at an early stage, such that satellite clusters formed after 12 to 24 hours. Subsequently, after 24 to 32 hours, a flagellum-dependent dispersal of cells became visible, extending laterally outward from a line of flagellum-independent motility. These modes of taxis were found in several environmental isolates and in a variety of mutants, including a strain deficient in the production of the R. capsulatus acyl-homoserine lactone quorum-sensing signal. Although there was great variability in the direction of movement in illuminated plates, cells were predisposed to move toward broad spectrum white light. This predisposition was increased by the use of square plates, and a statistical analysis indicated that R. capsulatus is capable of genuine phototaxis. Therefore, the variability in the direction of cell movement was attributed to optical effects on light waves passing through the plate material and agar medium.

  5. Rhodobacter capsulatus porphobilinogen synthase, a high activity metal ion independent hexamer

    Directory of Open Access Journals (Sweden)

    Fairman Robert

    2004-11-01

    Full Text Available Abstract Background The enzyme porphobilinogen synthase (PBGS, which is central to the biosynthesis of heme, chlorophyll and cobalamins, has long been known to use a variety of metal ions and has recently been shown able to exist in two very different quaternary forms that are related to metal ion usage. This paper reports new information on the metal ion independence and quaternary structure of PBGS from the photosynthetic bacterium Rhodobacter capsulatus. Results The gene for R. capsulatus PBGS was amplified from genomic DNA and sequencing revealed errors in the sequence database. R. capsulatus PBGS was heterologously expressed in E. coli and purified to homogeneity. Analysis of an unusual phylogenetic variation in metal ion usage by PBGS enzymes predicts that R. capsulatus PBGS does not utilize metal ions such as Zn2+, or Mg2+, which have been shown to act in other PBGS at either catalytic or allosteric sites. Studies with these ions and chelators confirm the predictions. A broad pH optimum was determined to be independent of monovalent cations, approximately 8.5, and the Km value shows an acidic pKa of ~6. Because the metal ions of other PBGS affect the quaternary structure, gel permeation chromatography and analytical ultracentrifugation experiments were performed to examine the quaternary structure of metal ion independent R. capsulatus PBGS. The enzyme was found to be predominantly hexameric, in contrast with most other PBGS, which are octameric. A protein concentration dependence to the specific activity suggests that the hexameric R. capsulatus PBGS is very active and can dissociate to smaller, less active, species. A homology model of hexameric R. capsulatus PBGS is presented and discussed. Conclusion The evidence presented in this paper supports the unusual position of the R. capsulatus PBGS as not requiring any metal ions for function. Unlike other wild-type PBGS, the R. capsulatus protein is a hexamer with an unusually high specific

  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, 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.

  8. Degradation of p-nitrophenol by the phototrophic bacterium Rhodobacter capsulatus.

    Science.gov (United States)

    Roldán, M D; Blasco, R; Caballero, F J; Castillo, F

    1998-01-01

    The phototrophic bacterium Rhodobacter capsulatus detoxified p-nitrophenol and 4-nitrocatechol. The bacterium tolerated moderate concentrations of p-nitrophenol (up to 0.5 mM) and degraded it under light at an optimal O2 pressure of 20 kPa. The bacterium did not metabolize the xenobiotic in the dark or under strictly anoxic conditions or high O2 pressure. Bacterial growth with acetate in the presence of p-nitrophenol took place with the simultaneous release of nonstoichiometric amounts of 4-nitrocatechol, which can also be degraded by the bacterium. Crude extracts from R. capsulatus produced 4-nitrocatechol from p-nitrophenol upon the addition of NAD(P)H, although at a very low rate. A constitutive catechol 1, 2-dioxygenase activity yielding cis,cis-muconate was also detected in crude extracts of R. capsulatus. Further degradation of 4-nitrocatechol included both nitrite- and CO2-releasing steps since: (1) a strain of R. capsulatus (B10) unable to assimilate nitrate and nitrite released nitrite into the medium when grown with p-nitrophenol or 4-nitrocatechol, and the nitrite concentration was stoichiometric with the 4-nitrocatechol degraded, and (2) cultures of R. capsulatus growing microaerobically produced low amounts of 14CO2 from radiolabeled p-nitrophenol. The radioactivity was also incorporated into cellular compounds from cells grown with uniformly labeled 14C-p-nitrophenol. From these results we concluded that the xenobiotic is used as a carbon source by R. capsulatus, but that only the strain able to assimilate nitrite (E1F1) can use p-nitrophenol as a nitrogen source.

  9. Optimizing multi-step B-side charge separation in photosynthetic reaction centers from Rhodobacter capsulatus

    Energy Technology Data Exchange (ETDEWEB)

    Faries, Kaitlyn M. [Washington Univ., St. Louis, MO (United States); Kressel, Lucas L. [Argonne National Lab. (ANL), Argonne, IL (United States); Dylla, Nicholas P. [Argonne National Lab. (ANL), Argonne, IL (United States); Wander, Marc J. [Argonne National Lab. (ANL), Argonne, IL (United States); Hanson, Deborah K. [Argonne National Lab. (ANL), Argonne, IL (United States); Holten, Dewey [Washington Univ., St. Louis, MO (United States); Laible, Philip D. [Argonne National Lab. (ANL), Argonne, IL (United States); Kirmaier, Christine [Washington Univ., St. Louis, MO (United States)

    2016-02-01

    Using high-throughput methods for mutagenesis, protein isolation and charge-separation functionality, we have assayed 40 Rhodobacter capsulatus reaction center (RC) mutants for their P+ QB- yield (P is a dimer of bacteriochlorophylls and Q is a ubiquinone) as produced using the normally inactive B-side cofactors BB and HB (where B is a bacteriochlorophyll and H is a bacteriopheophytin). Two sets of mutants explore all possible residues at M131 (M polypeptide, native residue Val near HB) in tandem with either a fixed His or a fixed Asn at L181 (L polypeptide, native residue Phe near BB). A third set of mutants explores all possible residues at L181 with a fixed Glu at M131 that can form a hydrogen bond to HB. For each set of mutants, the results of a rapid millisecond screening assay that probes the yield of P+ QB- are compared among that set and to the other mutants reported here or previously. For a subset of eight mutants, the rate constants and yields of the individual B-side electron transfer processes are determined via transient absorption measurements spanning 100 fs to 50 μs. The resulting ranking of mutants for their yield of P+ QB- from ultrafast experiments is in good agreement with that obtained from the millisecond screening assay, further validating the efficient, high-throughput screen for B-side transmembrane charge separation. Results from mutants that individually show progress toward optimization of P+ HB- → P+ QB- electron transfer or initial P* → P+ HB- conversion highlight unmet challenges of optimizing both processes simultaneously.

  10. 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

  11. Le burnout chez les soignants: facteurs prédisposants et moyens de prévention

    OpenAIRE

    Tavares, Marlisa Orquidia Pereira; Nadot, Nicole

    2011-01-01

    Ce travail porte sur le burn-out chez les soignants donnant des prestations dans des services de psychiatrie, soins aigus et palliatifs. D’après les statistiques, 43,5% de la population en suisse romande a déjà vécu un épisode de burn-out. Cette pathologie est principalement retrouvée chez les soignants qui sont en contact direct avec la souffrance d’autrui, ainsi que la mort.

  12. 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

  13. Genetic and biochemical characterization of carotenoid biosynthesis mutants of Rhodobacter capsulatus.

    Science.gov (United States)

    Armstrong, G A; Schmidt, A; Sandmann, G; Hearst, J E

    1990-05-15

    We have used genetic and biochemical techniques to study carotenoid biosynthesis (crt) mutants of Rhodobacter capsulatus, a purple non-sulfur photosynthetic bacterium. All nine identified crt genes are located within the 46-kilobase pair photosynthesis gene cluster, and eight of the crt genes form a subcluster. We have studied the operon structure of the crt gene cluster using transposon Tn5.7 mutants. The Tn5.7 insertion sites in 10 mutants have been mapped to high resolution (25-267 base pairs) by Southern hybridization. Two insertions each map within the coding regions of the crtA, crtC, crtE, and crtF genes, and one insertion lies within the crtI gene. The insertion in crtI is not polar on the downstream crtB gene, suggesting that crtI and crtB may form two separate operons. Another insertion located in the 5' noncoding region between the divergent crtA and crtI genes has no effect on wild-type pigmentation and apparently lies between the promoters for these operons. A Tn5.7 mutation in the 3' region of crtA yields a bacteriochlorophyll-minus phenotype, while a 5' insertion affects only carotenoid biosynthesis. Regulatory signals for transcription of a downstream operon required for bacteriochlorophyll biosynthesis may thus overlap the coding region of crtA. We also present the first evidence for the functions of the crtB, crtE, and crtJ gene products using a new in vitro assay for the incorporation of [14C]isopentenyl pyrophosphate into carotenoid precursors and phytoene in cell-free extracts. Extracts from a crtE mutant accumulate [14C]prephytoene pyrophosphate, while those from crtB and crtJ mutants accumulate [14C]geranylgeranyl pyrophosphate. We therefore propose that CrtE is the phytoene synthetase and that CrtB, and possibly CrtJ, are components of the prephytoene pyrophosphate synthetase.

  14. Bilan de santé chez l’adulte

    Science.gov (United States)

    Ridley, Jane; Ischayek, Amanda; Dubey, Vinita; Iglar, Karl

    2016-01-01

    Résumé Objectif Décrire les mises à jour apportées à Soins préventifs - Fiche de contrôle© pour aider les médecins à se tenir au fait des plus récentes recommandations en matière de soins de santé préventifs. Qualité des données Une recension dans la base de données Ovid MEDLINE a été effectuée à l’aide de mots-clés et d’autres paradigmes pertinents au bilan de santé périodique. Des sources secondaires, comme le Groupe d’étude canadien sur les soins de santé préventifs, l’Agence de la santé publique du Canada, la base de données Trip et l’Infobanque de l’Association médicale canadienne, ont aussi fait l’objet d’une recherche. Nous avons révisé les recommandations relatives aux soins préventifs pour des adultes à risque moyen. Les recommandations de bonne qualité et passables sont présentées respectivement en caractères gras et italiques. Message principal La fiche de contrôle a été mise à jour en fonction des recommandations du Groupe d’étude canadien sur les soins de santé préventif relatives au dépistage de l’obésité (2015), du cancer du col (2013), de la dépression (2013), de l’ostéoporose (2013), de l’hypertension (2012), du diabète (2012, 2013) et du cancer du sein (2011). D’autres mises à jour se fondent sur les recommandations d’autres organisations canadiennes concernant le dépistage du VIH (2013), le dépistage des infections transmises sexuellement (2013), les immunisations (2012 à 2014), le dépistage de la dyslipidémie (2012), le counseling en fertilité chez la femme (2011, 2012) et le dépistage du cancer colorectal (2010). Certaines recommandations antérieures ont été éliminées et d’autres, peu étayées par des données probantes, n’ont pas été incluses. Conclusion Soins préventifs - Fiche de contrôle a été mise à jour pour inclure les recommandations récentes afin de permettre aux médecins de famille d’offrir des soins complets et fondés sur des

  15. Détérioration de la vision des couleurs chez les alcooliques chroniques

    OpenAIRE

    Cvetnić, B.; Arnautova, S.

    1988-01-01

    Nous avons étudié les fonctions de la vue chez 16 alcooliques chroniques. Puis nous avons comparé les résultats obtenus avec les analyses des fonctions visuelles chez un groupe de contrôle de 16 non-alcooliques; ces personnes étant toutes de même âge et même sexe. Au cours d'un examen clinique détaillé de I'oeil, nous avons examiné les fonctions visuelles suivantes: l'acuité visuelle, le champ visuel, la motilité des bulbomoteurs et la vision des couleurs. Cette dernière a été examinée par le...

  16. Tuberculose multirésistante chez l'enfant: à propos de deux cas

    Science.gov (United States)

    Slimani, Hajar; Bricha, Myriem; Sqalli, Fatima-Ezzahra; Hammi, Sanaa; Bourkadi, Jamal-Eddine

    2016-01-01

    La tuberculose multirésistante chez l'enfant est une forme grave de la tuberculose, présentant un problème majeur de santé surtout dans les pays en voie de développement. Nous présentons le cas de deux enfants suivis dans notre formation pour tuberculose multirésistante mis sous schéma thérapeutique de deuxième ligne. PMID:27279953

  17. Elastofibrome à double localisation dorsale et thoracique antérieure chez l'enfant

    Science.gov (United States)

    Mahmoudi, Abdelhalim; Bendahou, Mouhcine; Chater, lamiae; Amarti, Afaf; Bouabdallah, Youssef; Afifi, My Abderrahmane

    2015-01-01

    L’élastofibrome est une pseudotumeur des tissus mous typiquement localisée sous la pointe de l'omoplate. Il est caractérisé par la prolifération de tissus fibreux et adipeux et affecte plus fréquemment les femmes âgées. Nous présentons un cas d’élastofibrome chez une fille de 9 ans. PMID:26175827

  18. La leishmaniose viscérale chez l'adulte à propos de douze cas

    Science.gov (United States)

    Benbella, Imane; Aich, Fatima; Elkhiyat, Majdouline; Khalki, Hanane; Khermach, Assya; Bergui, Imane; Tlemçani, Imane; Hassani, Moncef Amrani

    2016-01-01

    La leishmaniose viscérale est une maladie à transmission vectorielle liée essentiellement, au niveau de pourtour méditerranéen, à l'infection par leishmania infantum. Habituellement rare chez l'adulte, sa prévalence a récemment connu une augmentation y compris chez les sujets immunocompétents. Le but de notre étude est de présenter le profil épidémiologique de la leishmaniose viscérale chez l'adulte ainsi que l'importance du diagnostique biologique dans l'identification de cette maladie. Notre étude s'est étendue sur six ans de Janvier 2009 à Janvier 2014, et a colligé douze patients hospitalisés au Centre Hospitalier Universitaire Hassan II de Fès. L'altération de l’état général et la splénomégalie ont dominé le tableau clinique. Sur le plan biologique, l'anémie a été quasi constante. La confirmation diagnostique a consisté en la mise en évidence du parasite au niveau de la moelle. L’évolution sous traitement a été favorable pour tous nos patients. Ainsi, la recrudescence que connait la leishmaniose viscérale chez l'adulte et son tableau clinique peu spécifique doit la faire évoquer devant toute splénomégalie fébrile, afin de permettre un diagnostic et une prise en charge thérapeutique précoces. PMID:27347283

  19. Prévention de la maladie thromboembolique veineuse chez le brûlé

    Science.gov (United States)

    Siah, S.; El Farouki, A.

    2014-01-01

    Summary Les complications thromboemboliques sont considérées comme rares chez le patient brûlé. Leur incidence varie selon les études réalisées. Les patients brûlés présentent de nombreux facteurs de risque favorisant la survenue de ces complications. Le diagnostic clinique de la thrombose veineuse profonde et de l’embolie pulmonaire reste difficile vu leur évolution infraclinique et la non spécificité des signes cliniques. L’échodoppler veineux et l’angioscanner thoracique constituent les éléments clés dans la stratégie diagnostique de la thrombose veineuse profonde et de l’embolie pulmonaire chez les patients brûlés. Le traitement ne diffère pas de celui administré aux autres patients non brûlés et victimes de la thrombose veineuse profonde et de l’embolie pulmonaire. La prophylaxie controversée entre les auteurs, est un sujet d’actualité. Plusieurs praticiens et organismes recommandent son utilisation de routine chez les patients brûlés à risque. Elle reste le seul moyen capable d’empêcher la survenue de la maladie thromboembolique veineuse capable d’engager le pronostic vital chez ces patients. Nous rapportons 6 observations de patients brûlés ayant développé une maladie thromboembolique veineuse. PMID:26170780

  20. Tuberculose multirésistante chez l'enfant: à propos de deux cas

    OpenAIRE

    Slimani, Hajar; Bricha, Myriem; Sqalli, Fatima-Ezzahra; Sanaa HAMMI; Bourkadi, Jamal-Eddine

    2016-01-01

    La tuberculose multirésistante chez l'enfant est une forme grave de la tuberculose, présentant un problème majeur de santé surtout dans les pays en voie de développement. Nous présentons le cas de deux enfants suivis dans notre formation pour tuberculose multirésistante mis sous schéma thérapeutique de deuxième ligne.

  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. Intérêt du dosage de la procalcitonine chez le sujet âgé

    OpenAIRE

    Stucker, Fabien; Hermann, François; Krause, Karl-Heinz

    2007-01-01

    La procalcitonine a été étudiée à de nombreuses reprises chez l'adulte jeune présentant des infections bactérienne comme marqueur spécifique et précoce de l'inflammation, ainsi que comme prédicteur de la sévérité de l'atteinte. L'intérêt de son dosage chez la personne âgée n'a jamais été démontré. Une étude observationnelle a donc été conduite chez 218 patients âgés, non sélectionnés, admis en secteur hospitalier et les sensibilités (24%) et spécificité (94%) de la procalcitonine comme prédic...

  3. Intérêt du dosage de la procalcitonine chez le sujet âgé

    OpenAIRE

    Stucker, Fabien

    2006-01-01

    La procalcitonine a été étudiée à de nombreuses reprises chez l'adulte jeune présentant des infections bactérienne comme marqueur spécifique et précoce de l'inflammation, ainsi que comme prédicteur de la sévérité de l'atteinte. L'intérêt de son dosage chez la personne âgée n'a jamais été démontré. Une étude observationnelle a donc été conduite chez 218 patients âgés, non sélectionnés, admis en secteur hospitalier et les sensibilités (24%) et spécificité (94%) de la procalcitonine comme prédic...

  4. Flexibilité et intentionnalité dans la communication gestuelle chez les grands singes1

    OpenAIRE

    Hobaiter, Catherine; Byrne, Richard W.

    2014-01-01

    La communication gestuelle des grands singes est un système riche et complexe. Elle est utilisée de manière flexible dans l’intention de communiquer des objectifs précis à des individus particuliers - en tant que telle, elle partage la plupart des attributs de base du langage humain et permet de soutenir l'idée que les deux systèmes ont une racine évolutive commune. Des avancées significatives sur le sujet ont été faites grâce aux études longitudinales de la communication gestuelle chez les g...

  5. Distribution, inegalite et concentration des revenus chez les immigrants ages au Canada, 1990

    OpenAIRE

    Basavarajappa, K.G.

    1999-01-01

    Bien qu'il existe d'abondantes etudes exposant les differences de revenu entre les immigrants et les autochtones ou entre les groupes d'immigrants eux meme, ces etudes ne tiennent pas compte de la distribution ni de la concentration des revenus. Comme ces deux aspects sont importants pour comprendre la repartition du bien-etre economique et le comportement des consommateurs chez ces groupes, ils jouent un role au niveau de la politique. En s'aidant des donnees du recensement de 1991, nous avo...

  6. Dynamique et enzymologie de la digestion chez l'huitre Crassostrea gigas

    OpenAIRE

    Boucaud, C; Lebesnerais, C; Lubet, P.; Lihrmann, I

    1983-01-01

    Chez Crassostrea gigas (Thunberg) des expériences d'alimentation contrôlée ont permis d'établir les modalités et la chronologie du transit alimentaire. Différentes activités enzymatiques en relation avec la digestion (glycosidases, esterases et peptidases) ont été localisées dans l'appareil digestif et ont permis de préciser les sites de digestion des glucides et des protides et les sites d'absorption. Un schéma explicatif des différentes étapes de la digestion est proposé.

  7. Troubles du sommeil chez les enfants et dynamique de famille, quelles interactions?

    OpenAIRE

    GENTET S.

    2014-01-01

    "Troubles du sommeil chez les enfants et dynamique de famille, quelles interactions?" C'est dans une perspective systémique que cette question sur les interactions entre un symptôme et le fonctionnement ou le vécu familial est posée. Ce mémoire rassemble des études de cas illustratifs de l'interaction entre la dynamique de famille et le symptôme des troubles du sommeil. Les participants à l'étude sont des familles dont l'un ou plusieurs des enfants souffrent de troubles du sommeil. L'analyse ...

  8. Uniform designation for genes of the Calvin-Benson-Bassham reductive pentose phosphate pathway of bacteria

    NARCIS (Netherlands)

    Tabita, F. Robert; Gibson, Janet L.; Bowien, Botho; Dijkhuizen, Lubbert; Meijer, Wilhelmus

    1992-01-01

    Structural and regulatory genes encoding enzymes and proteins of the reductive pentose phosphate pathway have been isolated from a number of bacteria recently. In the phototroph Rhodobacter sphaeroides, and in two chemoautotrophic bacteria, Alcaligenes eutrophus and Xanthobacter flavus, these genes

  9. L’infection bactérienne chez le patient brûlé

    Science.gov (United States)

    Le Floch, R.; Naux, E.; Arnould, J.F.

    2015-01-01

    Summary La mort d’un patient brûlé est le plus souvent causée par une infection, bactérienne dans la grande majorité des cas. La perte de la barrière cutanée, les dispositifs invasifs et l’immunodépression liée à la brûlure sont trois mécanismes concourant à la survenue de ces infections. Chez un patient inflammatoire, les signes infectieux généraux d’infection sont peu discriminants. Du fait de la gravité des infections chez ce patient, leur prévention est un paramètre essentiel de la prise en charge. En raison des particularités pharmacocinétiques des brûlés, les posologies d’antibiotiques doivent être adaptés et les dosages sanguins doivent être systématiques. A l’heure où les résistances deviennent préoccupantes, les recherches sur les thérapeutiques sur les alternatives thérapeutiques parmi lesquels les inhibiteurs de facteurs de virulence, les peptides antimicrobiens, les polyphénols, l’immunothérapie…) deviennent cruciales. L’une des possibilités thérapeutiques les plus prometteuses semble être la phagothérapie. PMID:27252607

  10. Carotenogenesis gene cluster and phytoene desaturase catalyzing both three- and four-step desaturations from Rhodobacter azotoformans.

    Science.gov (United States)

    Zhang, Jinhua; Lu, Lili; Yin, Lijie; Xie, Shen; Xiao, Min

    2012-08-01

    A carotenogenesis gene cluster from the purple nonsulfur photosynthetic bacterium Rhodobacter azotoformans CGMCC 6086 was cloned. A total of eight carotenogenesis genes ( crtA , crtI , crtB , tspO , crtC , crtD , crtE , and crtF ) were located in two separate regions within the genome, a 4.9 kb region containing four clustered genes of crtAIB - tspO and a 5.3 kb region containing four clustered genes of crtCDEF . The organization was unusual for a carotenogenesis gene cluster in purple photosynthetic bacteria. A gene encoding phytoene desaturase ( CrtI ) from Rba. azotoformans was expressed in Escherichia coli. The recombinant CrtI could catalyze both three- and four-step desaturations of phytoene to produce neurosporene and lycopene, and the relative contents of neurosporene and lycopene formed by CrtI were approximately 23% and 75%, respectively. Even small amounts of five-step desaturated 3,4-didehydrolycopene could be produced by CrtI . This product pattern was novel because CrtI produced only neurosporene leading to spheroidene pathway in the cells of Rba. azotoformans. In the in vitro reaction, the relative content of lycopene in desaturated products increased from 19.6% to 62.5% when phytoene reduced from 2.6 to 0.13 μM. The results revealed that the product pattern of CrtI might be affected by the kinetics.

  11. Coordinated Expression of fdxD and Molybdenum Nitrogenase Genes Promotes Nitrogen Fixation by Rhodobacter capsulatus in the Presence of Oxygen

    OpenAIRE

    Hoffmann, Marie-Christine; Müller, Alexandra; Fehringer, Maria; Pfänder, Yvonne; Narberhaus, Franz; Masepohl, Bernd

    2014-01-01

    Rhodobacter capsulatus is able to grow with N2 as the sole nitrogen source using either a molybdenum-dependent or a molybdenum-free iron-only nitrogenase whose expression is strictly inhibited by ammonium. Disruption of the fdxD gene, which is located directly upstream of the Mo-nitrogenase genes, nifHDK, abolished diazotrophic growth via Mo-nitrogenase at oxygen concentrations still tolerated by the wild type, thus demonstrating the importance of FdxD under semiaerobic conditions. In contras...

  12. Rhodobacter capsulatus nifA1 Promoter: High-GC −10 Regions in High-GC Bacteria and the Basis for Their Transcription

    OpenAIRE

    Richard, Cynthia L.; Tandon, Animesh; Kranz, Robert G.

    2004-01-01

    It was previously shown that the Rhodobacter capsulatus NtrC enhancer-binding protein activates the R. capsulatus housekeeping RNA polymerase but not the Escherichia coli RNA polymerase at the nifA1 promoter. We have tested the hypothesis that this activity is due to the high G+C content of the −10 sequence. A comparative analysis of R. capsulatus and other α-proteobacterial promoters with known transcription start sites suggests that the G+C content of the −10 region is higher than that for ...

  13. Overproduction of CcmG and CcmFHRc Fully Suppresses the c-Type Cytochrome Biogenesis Defect of Rhodobacter capsulatus CcmI-Null Mutants

    OpenAIRE

    Sanders, Carsten; Deshmukh, Meenal; Astor, Doniel; Kranz, Robert G.; Daldal, Fevzi

    2005-01-01

    Gram-negative bacteria like Rhodobacter capsulatus use intertwined pathways to carry out the posttranslational maturation of c-type cytochromes (Cyts). This periplasmic process requires at least 10 essential components for apo-Cyt c chaperoning, thio-oxidoreduction, and the delivery of heme and its covalent ligation. One of these components, CcmI (also called CycH), is thought to act as an apo-Cyt c chaperone. In R. capsulatus, CcmI-null mutants are unable to produce c-type Cyts and thus sust...

  14. The reductive half-reaction of xanthine dehydrogenase from Rhodobacter capsulatus: the role of Glu232 in catalysis.

    Science.gov (United States)

    Hall, James; Reschke, Stefan; Cao, Hongnan; Leimkühler, Silke; Hille, Russ

    2014-11-14

    The kinetic properties of an E232Q variant of the xanthine dehydrogenase from Rhodobacter capsulatus have been examined to ascertain whether Glu(232) in wild-type enzyme is protonated or unprotonated in the course of catalysis at neutral pH. We find that kred, the limiting rate constant for reduction at high [xanthine], is significantly compromised in the variant, a result that is inconsistent with Glu(232) being neutral in the active site of the wild-type enzyme. A comparison of the pH dependence of both kred and kred/Kd from reductive half-reaction experiments between wild-type and enzyme and the E232Q variant suggests that the ionized Glu(232) of wild-type enzyme plays an important role in catalysis by discriminating against the monoanionic form of substrate, effectively increasing the pKa of substrate by two pH units and ensuring that at physiological pH the neutral form of substrate predominates in the Michaelis complex. A kinetic isotope study of the wild-type R. capsulatus enzyme indicates that, as previously determined for the bovine and chicken enzymes, product release is principally rate-limiting in catalysis. The disparity in rate constants for the chemical step of the reaction and product release, however, is not as great in the bacterial enzyme as compared with the vertebrate forms. The results indicate that the bacterial and bovine enzymes catalyze the chemical step of the reaction to the same degree and that the faster turnover observed with the bacterial enzyme is due to a faster rate constant for product release than is seen with the vertebrate enzyme.

  15. Urea Utilization in the Phototrophic Bacterium Rhodobacter capsulatus Is Regulated by the Transcriptional Activator NtrC

    Science.gov (United States)

    Masepohl, Bernd; Kaiser, Björn; Isakovic, Nazila; Richard, Cynthia L.; Kranz, Robert G.; Klipp, Werner

    2001-01-01

    The phototrophic nonsulfur purple bacterium Rhodobacter capsulatus can use urea as a sole source of nitrogen. Three transposon Tn5-induced mutations (Xan-9, Xan-10, and Xan-19), which led to a Ure− phenotype, were mapped to the ureF and ureC genes, whereas two other Tn5 insertions (Xan-20 and Xan-22) were located within the ntrC and ntrB genes, respectively. As in Klebsiella aerogenes and other bacteria, the genes encoding urease (ureABC) and the genes required for assembly of the nickel metallocenter (ureD and ureEFG) are clustered in R. capsulatus (ureDABC-orf136-ureEFG). No homologues of Orf136 were found in the databases, and mutational analysis demonstrated that orf136 is not essential for urease activity or growth on urea. Analysis of a ureDA-lacZ fusion showed that maximum expression of the ure genes occurred under nitrogen-limiting conditions (e.g., serine or urea as the sole nitrogen source), but ure gene expression was not substrate (urea) inducible. Expression of the ure genes was strictly dependent on NtrC, whereas ς54 was not essential for urease activity. Expression of the ure genes was lower (by a factor of 3.5) in the presence of ammonium than under nitrogen-limiting conditions, but significant transcription was also observed in the presence of ammonium, approximately 10-fold higher than in an ntrC mutant background. Thus, ure gene expression in the presence of ammonium also requires NtrC. Footprint analyses demonstrated binding of NtrC to tandem binding sites upstream of the ureD promoter. Phosphorylation of NtrC increased DNA binding by at least eightfold. Although urea is effectively used as a nitrogen source in an NtrC-dependent manner, nitrogenase activity was not repressed by urea. PMID:11133958

  16. Une activation possible de l’allèle Sf chez l’amandier

    OpenAIRE

    Fernández i Martí, Angel V.; Alonso Segura, José Manuel; Kodad, Ossama; Socias i Company, Rafel

    2011-01-01

    L'auto-compatibilité est devenue l'objectif prioritaire de la plupart des programmes d'amélioration génétique de l'amandier (Prunus amygdalus Batsch) pour éviter les problèmes liés à la présence du système d'auto-incompatibilité gamétophytique de l'amandier, comme chez d'autres espèces du genre Prunus, appartenant à la famille Rosaceae. L'auto-incompatibilité est un mécanisme des plantes qui empêche leur auto-fertilisation en favorisant le croisement entre les différents génotypes. Le locus S...

  17. Variabilité de la morphologie chez Fusarium oxysporum f. sp. lycopersici

    OpenAIRE

    Henni, J.; Boisson, Claude; Geiger, Jean-Paul

    1994-01-01

    La variabilité morphologique chez #Fusarium oxysporum$ f. sp. #lycopersici$ a été recherchée à deux niveaux : au sein d'une population de conidies provenant du thalle d'un isolat (variabilité interclonale) et au sein d'une population de conidies provenant d'un thalle issu d'un clonage monospore (variabilité interclonale). Enfin, cette variabilité a été étudiée sur des cultures jeunes et âgées. L'ensemble des essais a été réalisé sur deux isolats. Les résultats mettent en évidence l'existence ...

  18. Un refus fasciné – L’ambivalence du religieux chez Tabucchi

    OpenAIRE

    De Poli, Fabrice

    2012-01-01

    Quand on lui demande quels livres il emporterait sur une île déserte, Tabucchi répond : « L’un de ceux-là, bien que je sois agnostique, serait, sans aucun doute, les Évangiles […], livre mystérieux, indéchiffrable même » (AE, p. 82). Quelle place peuvent prendre dès lors la religion et le religieux chez un auteur non religieux mais fasciné par les mystères et notamment par le plus grand de tous ? Si Tabucchi, qui se définit tour à tour agnostique, sceptique ou non croyant, récuse le dogmatism...

  19. Diagnostic et suivi de gestation chez la brebis : réalités et perspectives

    OpenAIRE

    El Amiri, Bouchra; Karen, A.; COGNIE, Y.; Sousa, N.M.; Hornick, J.-L.; Szenci, O.; Beckers, J.-F.

    2003-01-01

    Cet article décrit les différentes méthodes cliniques et de laboratoire utilisables pour établir le diagnostic de la gestation chez les ovins. Etant destinées à des applications dans les élevages, ces méthodes sont présentées en insistant sur la précocité de leur utilisation, sur les paramètres de sensibilité, de spécificité, d’exactitude de diagnostic positif, d’exactitude de diagnostic négatif et enfin sur leurs possibilités de dénombrement des fœtus. La méthode la plus précoce est le dosag...

  20. Les habiletés phonologiques chez des enfants sourds prélecteurs

    OpenAIRE

    PAIRE-FICOUT,L; Magnan, A.; ECALLE,J

    2003-01-01

    Deux tâches visant à tester les capacités à juger et à produire des rimes ont été proposées à trois groupes d'enfants prélecteurs de 5 ans (entendants, sourds ayant bénéficié du Langage Parlé Complété (LPC) et sourds sans LPC). Le LPC est un système manuel permettant un décodage complet de l'information phonologique. La variable similarité labiale a été manipulée afin d'examiner le rôle de cette modalité d'entrée visuelle sur l'habileté phonologique chez les enfants sourds. Les résultats indi...

  1. Syndrome Keratitis-Ichtyosis-Deafness (KID) chez un enfant togolais issu d'un mariage consanguin

    OpenAIRE

    Kombaté, Koussak; Saka, Bayaki; Landoh, Dadja Essoya; Mouhari-Toure, Abass; Akakpo, Séfako; Belei, Eric; Gnassingbé, Wanguena; Djibril, Mohaman Awalou; Tchangaï-Walla, Kissem; Pitché, Palokinam

    2015-01-01

    Le syndrome KID est une affection génétique rare associant kératite, ichtyose et surdité. Nous rapportons un cas dont la surdité s'est compliquée de mutisme chez un enfant togolais issu d'un mariage consanguin.Il s'agissait d'une fillette de 9 ans admise en dermatologie pour une peau sèche et une kératodermie palmoplantaire évoluant depuis l'enfance, une surdité sévère et un mutisme total évoluant depuis la naissance. Il n'y avait pas d'histoire familiale connue de syndrome KID. Les parents d...

  2. Effets associes a la mutation "coquille blanche" chez la caille japonaise

    OpenAIRE

    Monvoisin, Jean Louis; Merat, P; Coquerelle, Gerard; Costa da Silva, Jose

    1989-01-01

    Nous avons recherché les effets directs ou maternels sur diverses performances associés à un gène autosomal récessif (we), responsable de l’absence de pigmentation des coquilles d’oeufs chez la caille japonaise. A partir d’animaux des deux sexes de même origine, respectivement de génotype hétérozygote We+ we et homozygote récessif wewe, les croisements réciproques ♂ we we x ♀ We+ we et ♂ We+ we X ♀ we we ont été réalisés deux années consécutives. Ces croisements donnaient tous deux des...

  3. Torsion chronique d'une rate baladeuse chez un adolescent: à propos d'un cas

    Science.gov (United States)

    Dème, Hamidou; Akpo, Léra Géraud; Fall, Seynabou; Badji, Nfally; Ka, Ibrahima; Guèye, Mohamadou Lamine; Touré, Mouhamed Hamine; Niang, El Hadj

    2016-01-01

    La rate baladeuse ou errante est une anomalie rare, qui est le plus souvent décrite chez l'enfant. Ses complications parmi lesquelles figure la torsion de son pédicule sont fréquentes et peuvent engager le pronostic vital du patient. Nous rapportons un cas de torsion chronique du pédicule d'une rate baladeuse chez un patient de 17 ans, au long passé de douleurs épigastriques. Le tableau clinique était marqué par une masse épigastrique spontanément douloureuse, évoluant depuis 48 heures. L’échographie abdominale objectivait une rate ectopique hétérogène, hypertrophiée, en position épigastrique et un hématome sous capsulaire. Au doppler, on notait une torsion du pédicule splénique à deux tours de spires et un petit flux sur l'artère splénique. La tomodensitométrie abdominale avec injection de produit de contraste montrait un défaut de rehaussement parenchymateux d'une grosse rate ectopique épigastrique et un hématome sous capsulaire. Le diagnostic de torsion chronique du pédicule d'une rate baladeuse, compliquée de nécrose et d'hématome sous capsulaire était retenu. Il a été réalisé une splénectomie. Les suites opératoires étaient simples. Nous discutons l'apport de l’échographie et de la TDM dans le diagnostic de la torsion chronique du pédicule d'une rate baladeuse. PMID:27583079

  4. 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.

  5. 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

    2016-01-01

    ABSTRACT 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 (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. IMPORTANCE 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. PMID:26833411

  6. STRESS OXYDATIF ET PROFIL NUTRITIONNEL CHEZ UNE POPULATION ATTEINTE DE CANCER COLORECTAL DANS LA REGION DE TLEMCEN

    OpenAIRE

    HAMIDI, Nabila

    2015-01-01

    Le cancer colorectal (CCR) occupe la deuxième place en termes d'incidence et de mortalité en Algérie. L'objectif de ce travail est l'étude des facteurs de risque de CCR chez une population au niveau de l'Ouest algérien. Une étude cas témoins a été menée auprès 70 personnes dont 30 cancéreux et 40 témoins, en vue de déterminer quelques paramètres du statut oxydant/antioxydant chez les cas de CCR. Les marqueurs de stress oxydatif(le Malonaldéhyde (MDA), les protéines carbonylées (PC...

  7. Les Determinants du Desir De Grossesse chez les Femmes Seropositives sous Traitement AntiRetroviral dans le District de Rwamagana

    OpenAIRE

    Claudien Uwanyirigira; Cyprien Munyanshongore

    2013-01-01

    L’étude vise à analyser les déterminants du désir de grossesse chez les femmes séropositives sous traitement anti-retroviral, afin de contribuer à la réduction de la transmission du virus de la mère à l’enfant. Elle a pour objectifs spécifiques de déterminer la proportion des grossesses chez les femmes à sérologie VIH positive, d’évaluer l’attitude du personnel de santé à l’égard des messages à donner aux femmes séropositives sous ARVs en ce qui concerne le désir de la grossesse, et relever l...

  8. Apport des approches inspirees de la neuropsychologie au diagnostic d?autisme chez l?adulte: une etude 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...

  9. Distribution et extension de la résistance chloroplatique aux atrazines chez les adventices annuelles en France

    OpenAIRE

    GASQUEZ, Jacques; BARRALIS, Gilbert; Aigle, N.

    1982-01-01

    La résistance chloroplastique aux triazines a été observée en France chez 13 espèces, dont les auteurs précisent l’importance agronomique et la distribution géographique ; les 3 espèces qui présentent la plus grande dispersion sont Amaranthus retroflexus L., Chenopodium album L. et Solanum nigrum L.

  10. Spectral Diffusion and Electron-Phonon Coupling of the B800 BChl a Molecules in LH2 Complexes from Three Different Species of Purple Bacteria

    Science.gov (United States)

    Baier, J.; Gabrielsen, M.; Oellerich, S.; Michel, H.; van Heel, M.; Cogdell, R.J.; Köhler, J.

    2009-01-01

    We have investigated the spectral diffusion and the electron-phonon coupling of B800 bacteriochlorophyll a molecules in the peripheral light-harvesting complex LH2 for three different species of purple bacteria, Rhodobacter sphaeroides, Rhodospirillum molischianum, and Rhodopseudomonas acidophila. We come to the conclusion that B800 binding pockets for Rhodobacter sphaeroides and Rhodopseudomonas acidophila are rather similar with respect to the polarity of the protein environment but that the packaging of the αβ-polypeptides seems to be less tight in Rb. sphaeroides with respect to the other two species. PMID:19883604

  11. 硫酸酯化修饰葛仙米多糖工艺研究%Sulfation Modification of Polysaccharide Extracted from Nostoc sphaeroides Ktzing

    Institute of Scientific and Technical Information of China (English)

    朱玉婷; 谭姚; 莫开菊

    2011-01-01

    The orthogonal array design method was used to optimize three reaction conditions,including esterification reagent,temperature and reaction time,for the sulfation of crude polysaccharides extracted from Nostoc sphaeroides Ku..tzing by water extraction and subsequent alcohol precipitation.Besides,FTIR spectroscopic analysis was carried out to identify the structural difference of Nostoc sphaeroides Ku..tzing polysaccharides as a result of the sulfation reaction,and a correlation analysis was done between FTIR A1261/A1418 and degree of substitution(DS) of sulfated polysaccharides,as determined by the barium chloride-gelation method.The optimal sulfation reaction conditions were found to be: 1:4 chlorosulfonic acid-pyridine as esterification reagent for 6 h reaction at 70 ℃.Under the optimal sulfation conditions,the DS of the final products was 1.042.Meanwhile,the sulfated polysaccharide obtained revealed typical sulfated functional groups.The correlation coefficient between FTIR A1261/A1418 and DS of sulfated Nostoc sphaeroides Ku..tzing polysaccharides was 0.974.Therefore,infrared spectroscopy can be used to characterize the structural difference of sulfated polysaccharides and quantify the DS of sulfate groups.%采用氯磺酸-吡啶法合成硫酸酯化葛仙米多糖,利用正交设计对酯化试剂比例、反应温度及反应时间进行优化。通过傅里叶红外光谱分析酯化前后的结构差异,氯化钡-明胶比浊法测定取代度,并分析红外光谱法与取代度之间的相关性。结果表明:葛仙米多糖硫酸酯化修饰的最佳条件为V(氯磺酸)与V(吡啶)比例1:4、反应温度70℃、反应时间6h,此条件下取代度达到1.042;红外光谱分析表明,硫酸酯化后的葛仙米多糖具有硫酸酯键的特征吸收峰,其吸光度比值A1261/A1418与化学方法所测得的硫酸酯化取代度的相关系数达到0.974。红外光谱不仅可以表征硫酸酯化多

  12. La métamorphose du célibataire chez Rachilde

    Directory of Open Access Journals (Sweden)

    Vicky Gauthier

    2012-11-01

    Full Text Available Un personnage fort intéressant fait son entrée sur la scène du roman (mais aussi de la société à la fin du dix-neuvième siècle : le célibataire, qui devient peu à peu le héros de prédilection de la littérature fantastique. Écrivant et publiant à cette époque où la misogynie est à son paroxysme, l’écrivaine française Rachilde (1860-1953 semble de prime abord ne pas échapper à cette tendance : son œuvre, comme la littérature décadente, verse dans l’insolite, le morbide, la folie, la névrose, la perversion ; la femme y est considérée comme l’Autre, l’ennemie de l’homme entraînant le mal et la destruction. D’ailleurs, on y retrouve fréquemment ce personnage à la Dorian Gray ou à la Des Esseintes, notamment dans Le Mordu (1889, Les Hors Nature (1897, Refaire l’Amour (1927. Plus encore, et c’est peut-être là la plus grande originalité de Rachilde, une autre figure, plus marginale et peu répandue, émerge au sein de sa fiction ; le célibataire dandy et dilettante – si cher aux décadents – est, chez elle, femme. Également misanthrope désabusée – et peut-être même davantage puisqu’elle est consciente de son « pouvoir » et de ses possibilités d’action dans le monde dans lequel elle vit –, la femme célibataire chez Rachilde devient une force sur-naturelle et inquiétante, dont l’esprit, le corps et les traits en sont les signes prophétiques. Cet article portera sur l’étude de deux de ses romans L’Animale (1893 et La Jongleuse (1900 et s’intéressera tout particulièrement à leurs héroïnes respectives, Laure et Éliante, qui constituent deux profils, deux prototypes, du personnage de la femme célibataire rachildienne.

  13. Evaluation des complications cardiaques chez les hémodialysés chroniques de Dakar

    Science.gov (United States)

    Moustapha, Cissé Mouhamadou; Tall, Lemrabott Ahmed; Maria, Faye; Khodia, Fall; Moustapha, Faye; Fary, Ka El Hadji; Abdou, Niang; Boucar, Diouf

    2016-01-01

    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 d'identifier les principaux facteurs de risque cardiovasculaire. Méthodes Il s'agissait d'une étude rétrospective de 4 ans portant sur les dossiers de patients traités au moins 6 mois en hémodialyse et ayant des explorations cardio-vasculaires comportant une radiographie du thorax de face, un électrocardiogramme et une échographie cardiaque. Les données épidémiologiques, cliniques, paracliniques, les aspects évolutifs des complications cardiaques ont été recueillies pour chaque patient retenu. Résultats Trente huit dossiers de patients ont été inclus dans cette étude. L’âge moyen était de 52 ans ± 12,85 et le sex-ratio H/F de 1,53. Les complications cardiovasculaires étaient dominées par l'hypertrophie ventriculaire gauche (71,05%), la maladie coronaire (34,21%), l'insuffisance cardiaque congestive (18,42%), Calcifications vasculaires (5,78%), les troubles du rythme (7.89%), les fuites valvulaires mitrales (44,73%), tricuspidiennes (42,10%) et les accidents vasculaires cérébraux hémorragiques (5,26%). L'incidence moyenne de l'HVG était de 81% chez les patients hypertendus. Au cours de cette étude, 27 patients avaient poursuivi l'hémodialyse et 11 étaient décédés dont 6 de causes cardiovasculaires (54,55%). Conclusion L'hémodialyse est une technique d’épuration qui expose les patients à de multiples complications cardiovasculaires. PMID:27217869

  14. In vitro and in vivo safety assessment of edible blue-green algae, Nostoc commune var. sphaeroides Kützing and Spirulina plantensis.

    Science.gov (United States)

    Yang, Yue; Park, Youngki; Cassada, David A; Snow, Daniel D; Rogers, Douglas G; Lee, Jiyoung

    2011-07-01

    Blue-green algae (BGA) have been consumed as food and herbal medicine for centuries. However, safety for their consumption has not been well investigated. This study was undertaken to evaluate in vitro and in vivo toxicity of cultivated Nostoc commune var. sphaeroides Kützing (NO) and Spirulina platensis (SP). Neither NO nor SP contained detectable levels of microcystin (MC)-LA, MC-RR, MC-LW and MC-LR by LC/MS/MS. Cell viability remained ∼70-80% when HepG2 cells were incubated with 0-500 μg/ml of hexane, chloroform, methanol and water-extractable fractions of NO and SP. Four-week-old male and female C57BL/6J mice were fed an AIN-93G/M diet supplemented with 0%, 2.5% or 5% of NO and SP (wt/wt) for 6 months. For both genders, BGA-rich diets did not induce noticeable abnormality in weight gain and plasma alanine aminotransferase (ALT) and aspartate aminotransferase concentrations except a significant increase in plasma ALT levels by 2.5% NO supplementation in male mice at 6 month. Histopathological analysis of livers, however, indicated that BGA did not cause significant liver damage compared with controls. In conclusion, our results suggest that NO and SP are free of MC and the long-term dietary supplementation of up to 5% of the BGA may be consumed without evident toxic side-effects. PMID:21473896

  15. Amitié, harmonie et paix politique chez Aristote et Jean Bodin

    Directory of Open Access Journals (Sweden)

    Sara Miglietti

    2010-09-01

    Full Text Available La crise politique et religieuse de la seconde moitié du xvie siècle ouvre la voie en France à un débat enflammé concernant les limites du pouvoir souverain et le rôle du peuple au sein de l’État. Dans les Six livres de la République (1576, Jean Bodin développe un programme de réforme éthico-politique envisageant l’amitié entre les citoyens comme pierre angulaire de l’État. Bien que s’inspirant largement des réflexions d’Aristote sur le même sujet (Éthique à Nicomaque, Politique, il remplace toutefois la théorie aristotélicienne de l’amitié-égalité (laquelle entraîne chez le Stagirite une vision égalitariste de la société et un net refus de la monarchie par une nouvelle théorie de l’amitié-harmonie qui lui permet de justifier la nature hiérarchique et monarchique de sa « République bien ordonnée ».

  16. Hydrogen production by hup(-) mutant and wild-type strains of Rhodobacter capsulatus from dark fermentation effluent of sugar beet thick juice in batch and continuous photobioreactors.

    Science.gov (United States)

    Uyar, Basar; Gürgan, Muazzez; Özgür, Ebru; Gündüz, Ufuk; Yücel, Meral; Eroglu, Inci

    2015-10-01

    Photofermentative production of hydrogen is a promising and sustainable process; however, it should be coupled to dark fermentation to become cost effective. In order to integrate dark fermentation and photofermentation, the suitability of dark fermenter effluents for the photofermentative hydrogen production must be demonstrated. In this study, thermophilic dark fermenter effluent (DFE) of sugar beet thick juice was used as a substrate in photofermentation process to compare wild-type and uptake hydrogenase-deficient (hup (-)) mutant strains of Rhodobacter capsulatus by means of hydrogen production and biomass growth. The tests were conducted in small-scale (50 mL) batch and large-scale (4 L) continuous photobioreactors in indoor conditions under continuous illumination. In small scale batch conditions, maximum cell concentrations were 0.92 gdcw/L c and 1.50 gdcw/L c, hydrogen yields were 34 % and 31 %, hydrogen productivities were 0.49 mmol/(L c·h) and 0.26 mmol/(Lc·h), for hup (-) and wild-type cells, respectively. In large-scale continuous conditions, maximum cell concentrations were 1.44 gdcw/L c and 1.87 gdcw/L c, hydrogen yields were 48 and 46 %, and hydrogen productivities were 1.01 mmol/(L c·h) and 1.05 mmol/(L c·h), for hup (-) and wild-type cells, respectively. Our results showed that Rhodobacter capsulatus hup (-) cells reached to a lower maximum cell concentration but their hydrogen yield and productivity were in the same range or superior compared to the wild-type cells in both batch and continuous operating modes. The maximum biomass concentration, yield and productivity of hydrogen were higher in continuous mode compared to the batch mode with both bacterial strains.

  17. Hydrogen production by Hup{sup -} mutant and wild type strains of Rhodobacter capsulatus on dark fermenter effluent of sugar beet thick juice in batch and continuous photobioreactors

    Energy Technology Data Exchange (ETDEWEB)

    Oezguer, Ebru [Middle East Technical Univ., Ankara (Turkey). Dept. of Chemical Engineering; Uyar, Basar [Kocaeli Univ. (Turkey). Dept. of Chemical Engineering; Guergan, Muazzez; Yuecel, Meral [Middle East Technical Univ., Ankara (Turkey). Dept. of Biology

    2010-07-01

    The HYVOLUTION project (EU 6th frame) is aimed to develop an integrated process in which biomass is fermented to acetate, lactate, CO{sub 2} and hydrogen followed by photofermentation of acetate and lactate to hydrogen and CO{sub 2} with photosynthetic purple nonsulfur bacteria (PNS bacteria). Growth and hydrogen production of Rhodobacter capsulatus was investigated on the dark fermenter effluent of thick juice (processed raw sugar beet juice) which contained acetate and NH{sub 4}Cl. In this effluent media, the hydrogen production of wild type bacterium and an uptake-hydrogenase deficient mutant (hup-) were compared in small scale (55 ml) batch and large scale (4 L) continuous photobioreactors in indoor conditions under constant illumination of 2000 lux. In continuous operation mode, the overall hydrogen production yields were 1.84 and 1.92 mol H{sub 2}/mol acetate, the maximum hydrogen productivities were 1.29 and 0.89 mmol H{sub 2}/L.h, for the wild type and mutant strains, respectively. On the other hand, in batch operation mode, the overall hydrogen production yields were 1.25 and 1.44 mol H{sub 2}/mol acetate, the maximum hydrogen productivities were 0.28 and 0.52 mmol H{sub 2}/L.h, for the wild type and mutant strains, respectively. The results show that Rhodobacter capsulatus is capable of using sugar beet thick juice effluent as substrate for hydrogen production; which makes it a suitable bacterium to be employed in integrated termophilic fermentation-photofermentation process. (orig.)

  18. Hydrogen production by hup(-) mutant and wild-type strains of Rhodobacter capsulatus from dark fermentation effluent of sugar beet thick juice in batch and continuous photobioreactors.

    Science.gov (United States)

    Uyar, Basar; Gürgan, Muazzez; Özgür, Ebru; Gündüz, Ufuk; Yücel, Meral; Eroglu, Inci

    2015-10-01

    Photofermentative production of hydrogen is a promising and sustainable process; however, it should be coupled to dark fermentation to become cost effective. In order to integrate dark fermentation and photofermentation, the suitability of dark fermenter effluents for the photofermentative hydrogen production must be demonstrated. In this study, thermophilic dark fermenter effluent (DFE) of sugar beet thick juice was used as a substrate in photofermentation process to compare wild-type and uptake hydrogenase-deficient (hup (-)) mutant strains of Rhodobacter capsulatus by means of hydrogen production and biomass growth. The tests were conducted in small-scale (50 mL) batch and large-scale (4 L) continuous photobioreactors in indoor conditions under continuous illumination. In small scale batch conditions, maximum cell concentrations were 0.92 gdcw/L c and 1.50 gdcw/L c, hydrogen yields were 34 % and 31 %, hydrogen productivities were 0.49 mmol/(L c·h) and 0.26 mmol/(Lc·h), for hup (-) and wild-type cells, respectively. In large-scale continuous conditions, maximum cell concentrations were 1.44 gdcw/L c and 1.87 gdcw/L c, hydrogen yields were 48 and 46 %, and hydrogen productivities were 1.01 mmol/(L c·h) and 1.05 mmol/(L c·h), for hup (-) and wild-type cells, respectively. Our results showed that Rhodobacter capsulatus hup (-) cells reached to a lower maximum cell concentration but their hydrogen yield and productivity were in the same range or superior compared to the wild-type cells in both batch and continuous operating modes. The maximum biomass concentration, yield and productivity of hydrogen were higher in continuous mode compared to the batch mode with both bacterial strains. PMID:26164274

  19. Méningo-encéphalite à Streptococcus agalactiae chez l'adulte non immunodéprimé

    OpenAIRE

    Rafai, Mostafa; Chouaib, Naoufal; Zidouh, Saad; Bakkali, Hicham; Belyamani, Lahcen

    2015-01-01

    Streptococcus agalactiae est un Streptocoque beta-hémolytique du groupe B (SGB), c'est un germe commensal occasionnel de la peau, du tube digestif et des voies génito-urinaires. Nous rapportons un cas inhabituel d'une méningo-encéphalite due au Streptococcus agalactiae (SGB) multisensible à l'antibiogramme chez un sujet adulte immunocompétent admis au service des urgences pour prise en charge de troubles de conscience fébrile. L’évolution clinique et biologique à J10 était favorable et le pat...

  20. La prévention des blessures non intentionnelles chez les enfants et adolescents autochtones au Canada

    OpenAIRE

    Banerji, Anna

    2012-01-01

    Les blessures non intentionnelles sont la principale cause de décès chez les enfants et adolescents autochtones canadiens, à un taux de trois à quatre fois la moyenne nationale. Non seulement les décès et les blessures invalidantes dévastent les familles et les communautés, mais elles font également d’énormes ravages sur les ressources de santé. L’absence de statistiques, de surveillance continue ou de programmes de prévention des blessures à l’égard des enfants et adolescents autochtones exa...

  1. Traitement syllabique en lecture chez des enfants sourds : effet du Langage Parlé Complété

    OpenAIRE

    PAIRE-FICOUT,L; Magnan, A.

    2001-01-01

    Une adaptation visuelle du paradigme de Mehler et al. (1981) est utilisée pour comparer le traitement de l'unité syllabique en lecture de mots isolés chez six enfants sourds pratiquant le LPC (système manuel qui permet de compléter l'information labiale) et six enfants sourds sans LPC. Les enfants doivent indiquer si une cible visuelle de deux ou trois lettres de structure syllabique CV ou CVC se trouve à l'initiale d'un mot (par exemple la cible BA ou BAL est présentée avant le mot BALADE ou...

  2. Variations observees dans l'etat de developpement des systemes foliaire et racinaire chez la semence mure de mais

    OpenAIRE

    Juguet, M.; DERIEUX, M.; Duburcq, J.B.

    1986-01-01

    L’étude quantitative des racines et des feuilles préformées dans la semence mûre a été menée chez cinq hybrides de maïs, permettant de déterminer le « capital embryonnaire » disponible pour la germination. Parmi les différences observées, l’hybride A632 x W 117 se distingue par un plus grand développement des feuilles.

  3. Properties of a Tn5 insertion mutant defective in the structural gene (fruA) of the fructose-specific phosphotransferase system of Rhodobacter capsulatus and cloning of the fru regulon.

    OpenAIRE

    Daniels, G A; Drews, G; Saier, M H

    1988-01-01

    In photosynthetic bacteria such as members of the genera Rhodospirillum, Rhodopseudomonas, and Rhodobacter a single sugar, fructose, is transported by the phosphotransferase system-catalyzed group translocation mechanism. Previous studies indicated that syntheses of the three fructose catabolic enzymes, the integral membrane enzyme II, the peripheral membrane enzyme I, and the soluble fructose-1-phosphate kinase, are coordinately induced. To characterize the genetic apparatus encoding these e...

  4. La représentation de l’artiste chez J.-K.Huysmans

    Directory of Open Access Journals (Sweden)

    Momoko Fukuda

    2012-03-01

    Full Text Available The object of this article is to situate J.-K. Huysmans' En ménage in his work as a whole and more generally in the tradition of the "roman d'art" in 19th Century French literature. "Roman d'art" works, such as the Goncourt brothers' Manette Salomon or Zola's OEuvre, often focus on the incompatibility of the artist's creative force and his love for a woman. Even if a woman appears as a muse at first, she often becomes an obstacle to the vocation of the artist.Even though the artist is very important in Huysmans' novels, he does not directly treat the opposition between love and creation. If a woman brings problems, it is not because of her influence on the creativity of the artist, but due to a particular theme developed by Huysmans: how to assure material comfort without being disturbed by 21 Ibid., p. 474. Fukuda, La représentation de l'artiste chez J.-K.Huysmans Nordlit 28, 2011 62 female presence? This problem is exaggerated by the artistic profession, which involves working at home.Not being capable of doing housework, Huysmans' hero cannot live totally alone. André, the hero of En ménage, leaves his wife who has been unfaithful to begin a single life with a housemaid. In his relationships with his wife, his housemaid and his lover, all he worries about is his work environment. Nevertheless, he ends up creating nothing, not because of a woman, but because of his own mediocrity and laziness. In this "roman d'art" without a muse, André's character is typical of Huysmans' comical but harsh realism, which subverts the myth of the artist torn between love and creation.

  5. Etude morphométrique de l'oreille externe chez les jeunes adultes

    Science.gov (United States)

    Nyemb, Philippe Manyacka Ma; Sankale, Anne-Aurore; Ndiaye, Lamine; NDiaye, Aïnina; Gaye, Magaye

    2014-01-01

    Introduction Connaitre les dimensions normales de l'oreille externe constitue un pré-requis en chirurgie. Le but de ce travail est de déterminer les valeurs moyennes des différentes mesures morphométriques des oreilles gauches et droites dans notre population d’étude. Méthodes Notre groupe d’étude était constitué de 100 sujets adultes jeunes (50 femmes et 50 hommes) âgés de 18 à 25 ans, et exempts de traumatismes ou d'anomalies congénitale de l'oreille externe. Les différentes mesures répertoriées étaient représentées par: la hauteur totale de l'oreille, la largeur totale de l'oreille, la hauteur lobulaire, la largeur lobulaire, la distance tragus - anti-hélix, la distance tragus - hélix, ainsi que la projection de l'oreille. Résultats L’âge moyen de notre population d’étude était de 22 ans. La hauteur totale de l'oreille était respectivement de 61,6 et 60,3 mm chez les sujets de sexe masculin et féminin. La largeur totale retrouvée était respectivement de 32,5 et 30,8 mm. Pour toutes les distances mesurées, nous retrouvions des différences entre hommes et femmes, ainsi que d'un coté à l'autre. Conclusion Pour le clinicien, il est important de prendre en compte les mesures morphométriques de l'oreille externe non seulement dans un but diagnostic, mais également pour reproduire lors de sa reconstruction une oreille anatomiquement correcte. PMID:25932068

  6. Analyse de l'efficacité de l'accoutumance à l'eau chez l'enfant préscolaire

    OpenAIRE

    Mornard, Manhattan; Deflandre, Dorian; Delvaux, Anne; Cloes, Marc; Jidovtseff, Boris

    2014-01-01

    L'accoutumance à l'eau apparaît comme un prérequis indispensable à l'apprentissage des techniques de nage. Après différents tests chez des enfants en bas âge, l'étude confirme l'efficacité à l'accoutumance à l'eau. Peer reviewed

  7. 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.

  8. 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

  9. 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.

  10. 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.)

  11. Etude protéomique du vieillissement musculaire chez la femme post-ménopausée

    OpenAIRE

    Gueugneau, Marine; Coudy-Gandilhon, Cécile; Chambon, Christophe; Picard, Brigitte; Bijislma, A.; Maier, A.; Attaix, Didier; Butler-Browne, G.; Bechet, Daniel

    2013-01-01

    Introduction et Méthodes : Une approche protéomique a été développée afin identifier de nouveaux biomarqueurs du vieillissement musculaire (sarcopénie). Des extraits totaux et sarcoplasmiques ont été préparés à partir de femmes ménopausées matures (54 ans) et âgées (78 ans). Sur un total de 1919 spots, 133 sont exprimés de façon différentielle chez les femmes âgées par rapport aux femmes matures, et la spectrométrie de masse (nanoLC-MS/MS) a permis d’identifier 74 protéines différentes. Résul...

  12. Clonage de l'IGF-I et de son récepteur chez le turbot (Psetta maxima)

    OpenAIRE

    ELIES G.; Duval, H.; GROIGNO L.; Wolff, J.; Boeuf, G.; BOUJARD D.

    1998-01-01

    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 verté...

  13. Extraction industrielle de protéines et de pigments chez la luzerne : état des lieux et perspectives

    OpenAIRE

    Andurand , J.; Coulmier, D; Despres, J.L.; Rambourg , J.C.

    2010-01-01

    L’extraction industrielle de protéines et de pigments chez la luzerne permet d’obtenir à partir des feuilles de cette légumineuse un concentré protéique riche en pigments et en acides gras oméga 3. Ce process de pointe reste moins énergivore que la déshydratation classique, même en prenant en compte les importantes économies énergétiques de la filière de déshydratation de fourrages de ces deux dernières années. Aujourd’hui, les débouchés principaux de ce concentré sont le marché de matières p...

  14. 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.

  15. Heterologous production of two unusual acyclic carotenoids, 1,1'-dihydroxy-3,4-didehydrolycopene and 1-hydroxy-3,4,3',4'-tetradehydrolycopene by combination of the crtC and crtD genes from Rhodobacter and Rubrivivax.

    Science.gov (United States)

    Steiger, Sabine; Takaichi, Shinichi; Sandmann, Gerhard

    2002-07-17

    Acyclic hydroxy carotenoids were produced from lycopene and 3,4-didehydrolycopene in Escherichia coli by combining different carotenogenic genes including the carotene hydratase gene crtC and the carotene 3,4-desaturase gene crtD. The genes originated either from Rhodobacter species or Rubrivivax gelatinosus. It was shown that the product of crtD from Rubrivivax unlike the one from Rhodobacter is able to convert 1-HO-3,4-didehydrolycopene to 1-HO-3,4,3',4'-tetradehydrolycopene (=3,4,3',4'-tetradehydro-1,2-dihydro-psi,psi-caroten-1-ol). Thus, only when the desaturase from Rubrivivax is expressed can this novel carotenoid be obtained. In the presence of crtC from Rubrivivax, another carotenoid 1,1'-(HO)(2)-3,4-didehydrolycopene (=3,4-didehydrolycopene-1,2,1',2'-tetrahydro-psi,psi-caroten-1,1'-diol) not found in a non-transgenic organism before is formed in E. coli. Its accumulation under these conditions and its absence when crtC from Rubrivivax is replaced by the corresponding gene from Rhodobacter is discussed. The function of the different crtC and crtD genes in the pathway leading to the individual carotenoids is outlined. Since 1,1'-(HO)(2)-3,4-didehydrolycopene could not be produced in substantial amounts and 1-HO-3,4,3',4'-tetradehydrolycopene has not been described before, their structural characteristics were determined for the definite assignment of their identity. This included spectral properties, determination of relative molecular mass as well as the number of hydroxy groups by mass spectroscopy and NMR spectroscopy for 1,1'-(HO)(2)-3,4-didehydrolycopene.

  16. 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

  17. Apparences corporelles et politique matrimoniale chez les Habsbourg à la fin du Moyen Âge

    Directory of Open Access Journals (Sweden)

    Cyrille Debris

    2008-08-01

    Full Text Available Résumé : Les mariages chez les Habsbourg de la fin du Moyen Âge ont une relation évidente avec les apparences puisqu’ils impliquent une dimension physique déterminante et double : objective et subjective. La procréation étant le premier but, il fallait que les époux fussent physiquement aptes mais aussi attirants. Les apparences intervenaient à différentes étapes dans les négociations matrimoniales : d’abord au niveau des motivations, puis des vérifications, enfin dans les rituels, parfois un peu étranges. Les portraits pouvaient aider au choix du conjoint, lorsque plusieurs projets concurrents étaient en lice, mais surtout illustraient les descriptions des ambassadeurs promus « entremetteurs », pourvu qu’ils fussent réalistes. Les négociateurs, à différents stades des tractations, pouvaient exiger de voir les fiancées putatives dûment préparées (la présentation de la fiancée ou Brautschau, même si elles n’avaient aucune voix au chapitre et étaient très jeunes. Enfin, l’examen était régulièrement complété par une enquête « médicale » pour juger du physique des fiancés, dans leur nudité, au risque d’une rétractation par clause suspensive. Finalement, cela n’enlevait pas l’appréhension lors de la première rencontre in persona entre les deux fiancés, qui jusque là avaient dû s’en remettre à des médiateurs pour ce qui toucherait leur vie intime.Abstract: Appearances had an evident impact on the Habsburg marriages at the end of the Middle Ages because it implied a decisive physical aspect, which is both objective and subjective. Procreation being the first goal, spouses had to be physically fit and be attracted to each other. Appearance played a role in the different steps of the nuptial negotiations : in the motivations, verifications and rituals. Portraits could help in choosing a partner, but above all, they helped to illustrate the descriptions made by the ambassadors

  18. 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

  19. Procalcitonine, marqueur de mortalité précoce chez le sujet très âgé

    OpenAIRE

    Gavazzi, Gaetan; Stucker, Fabien; Herrmann, François; Graf, Jean-Daniel; Michel, Jean-Pierre

    2009-01-01

    La procalcitonine est un biomarqueur d'infection mais aussi de sévérité des infections, notamment chez les patients admis en hospitalisation en court séjour. Le pronostic des pathologies aiguës chez le sujet âgé est difficile à évaluer car il est à la fois lié à la pathologie aiguë et à d'autres facteurs tels que le statut fonctionnel ou les pathologies chroniques associées. Peu de biomarqueurs ont été étudiés dans ce cadre. L'objectif de cette étude était d'évaluer l'intérêt de la procalcito...

  20. Impact du Lab-score sur la prescription d'antibiotiques chez l'enfant avec état fébrile sans foyer

    OpenAIRE

    Lacroix, Laurence Elisabeth

    2015-01-01

    Le Lab-score, combinant les résultats de protéine C-Réactive (CRP), procalcitonine et stix urinaire, a démontré une excellente capacité de détection de l’infection bactérienne sévère chez l’enfant avec état fébrile sans foyer. Notre étude visait à analyser son impact prospectif sur la réduction du taux de prescription d’antibiotiques chez l’enfant de 7 jours à 3 ans souffrant d’un état fébrile sans foyer. Malgré les excellentes caractéristiques diagnostiques du Lab-score, l’utilisation de ce ...

  1. Analyse de l’interaction entre les gènes d’avirulence AvrLm3 et AvrLm4-7 chez Leptosphaeria maculans

    OpenAIRE

    Plissonneau, Clémence; Balesdent, Marie-Helene; Fudal, Isabelle; Rouxel, Thierry

    2014-01-01

    Leptosphaeria maculans est un champignon ascomycète responsable de la nécrose du collet du colza, principale maladie sur cette culture. La méthode de lutte la plus utilisée contre cet agent pathogène est la lutte génétique. Celle-ci repose sur l'interaction entre un gène de résistance Rlm chez la plante et un gène d'avirulence AvrLm chez le champignon. L’un d’eux, AvrLm4-7, joue un rôle important dans la fitness fongique1 et a été cloné2. Récemment, nous avons mis en évidence une corrélation ...

  2. Les capacités osmorégulatrices chez la crevette bleue Litopenaeus stylirostris, au cours de l’ontogenèse

    OpenAIRE

    Pham, Dominique

    2011-01-01

    L’étude de l’ontogenèse de l’osmorégulation a été entreprise chez la crevette bleue Litopenaeus stylirostris en Nouvelle-Calédonie. L’implication des tissus de la cavité branchiale dans la régulation ionique a été déterminée au préalable chez des juvéniles par immunolocalisation de trois transporteurs protéiques d’ions, ( la NKA, le co-transporteur NKCC1 et le CFTR ) et par la détection de ionocytes en microscopie électronique. Le rôle de la NKA a été particulièrement étudié et son implicatio...

  3. Anoplastie périnéale simple pour le traitement des malformations anorectales basses chez l'adulte, à propos de deux cas

    OpenAIRE

    Abdelmoughit ECHCHAOUI; 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 le...

  4. Open reading frame 5 (ORF5), encoding a ferredoxinlike protein, and nifQ are cotranscribed with nifE, nifN, nifX, and ORF4 in Rhodobacter capsulatus.

    OpenAIRE

    Moreno-Vivian, C; Hennecke, S; Pühler, A; Klipp, W

    1989-01-01

    DNA sequence analysis of a 1,600-base-pair fragment located downstream of nifENX in nif region A of Rhodobacter capsulatus revealed two additional open reading frames (ORFs): ORF5, encoding a ferredoxinlike protein, and nifQ. The ferredoxinlike gene product contained two cysteine motifs, typical of ferredoxins coordinating two 4Fe-4S clusters, but the distance between these two motifs was unusual for low-molecular-weight ferredoxins. The R. capsulatus nifQ gene product shared a high degree of...

  5. Study on Anti-Coagulant Activity of Sulfated Nsotoc Sphaeroides Kützing Polysaccharide%葛仙米多糖硫酸酯抗凝血活性研究

    Institute of Scientific and Technical Information of China (English)

    朱玉婷; 袁杰; 杨洁; 田瑞; 曾智; 莫开菊

    2014-01-01

    This paper investigated the anticoagulant activity of Nostoc Sphaeroides Kützing polysaccha-ride’ s sulfuric acid ester,whose substitution degrees were 0,0.51,1.01 respectively.The results showed:Nostoc Sphaeroides Kützing polysaccharide’ s sulfuric acid ester could obviously prolong APTT and TT, and depended on the concentration but did not play a significant role to PT.So the results mainly illustra-ted that it played the function of anticlotting through inhibiting endogenous blood coagulation process and conjunct blood coagulation way,but it showed weak effect on exogenous blood coagulation way.%以取代度为0、0.51、1.01的葛仙米多糖硫酸酯为原料,探讨了各样品的抗凝血活性.结果表明:葛仙米多糖硫酸酯能显著延长人活化部分凝血活酶时间(APTT)和凝血酶时间(TT),且具有一定的剂量效应关系,但对凝血酶原时间(PT)的作用不明显.说明其主要是通过抑制内源性凝血过程及共同凝血途径发挥抗凝血作用,对外源凝血途径影响较弱.

  6. Métastases pleuropulmonaires révélant un mélanome malin de la conjonctive chez un sujet jeune

    Science.gov (United States)

    El Ouazzani, Hanane; Janah, Hicham; El Machichi, Sabah Alami; Achachi, Leila; Fihry, Mohamed Taoufiq El Fassy; El Ftouh, Mohamed

    2016-01-01

    Le mélanome de la conjonctive est une tumeur rare avec une incidence de 0,03 à 0,08 pour 100000 dans la population blanche. Le mélanome malin métastatique constitue environ 5% de toutes les tumeurs malignes secondaires du poumon. Nous rapportons un cas de métastase pleurale et pulmonaire d'un mélanome conjonctival de découverte fortuite chez un sujet jeune. PMID:27231507

  7. Localisations particulières de l'histiocytose langerhansienne chez l'enfant, scapula et pubis: à propos de deux cas

    Science.gov (United States)

    Atarraf, Karima; Chater, Lamiae; Arroud, Mounir; Afifi, My Abderrahman

    2014-01-01

    L'histiocytose X ou histiocytose de Langerhans est une maladie de l'enfant et de l'adulte jeune. Dont l'incidence est estimée à 1 cas sur 200 000 par an. C'est une maladie au spectre clinique très divers, allant du simple granulome éosinophile à la forme grave multiviscérale avec dysfonctionnement d'organe. Les auteurs rapportent deux observations concernant deux localisations assez rares de cette maladie, au niveau du pubis chez le premier enfant, et au niveau de la scapula chez le deuxième. Chez nos deux malades la localisation était focale, et l’évolution était favorable. A travers ces deux observations, nous allons essayer de décrire les différents aspects cliniques et radiologiques et discuter a travers une revue de littérature les démarches diagnostiques et thérapeutiques de cette maladie rare. PMID:25478049

  8. The Effects of Rhodobacter capsulatus KCTC-2583 on Cholesterol Metabolism, Egg Production and Quality Parameters during the Late Laying Periods in Hens.

    Science.gov (United States)

    Lokhande, Anushka; Ingale, S L; Lee, S H; Kim, J S; Lohakare, J D; Chae, B J; Kwon, I K

    2013-06-01

    An experiment was conducted to investigate the effects of dietary supplementation of Rhodobacter capsulatus KCTC-2583 on egg-yolk and serum cholesterol, egg production and quality parameters during the late laying periods in hens. A total of 160 Hy-Line Brown layers (54 wk-old) were randomly allotted to 4 treatment groups on the basis of laying performance. Each treatment had 4 replicates with 10 birds each (40 birds per treatment). Two hens were confined individually with cage size 35×35×40 cm and each 10 birds (5 cages) shared a common feed trough between them forming one experimental unit. Dietary treatments were; basal diet supplemented with 0 (control), 0.05, 0.10 and 0.15% R. capsulatus KCTC-2583. Experimental diets were fed in meal form for 56 d. Dietary supplementation of increasing levels of R. capsulatus KCTC-2583 reduced (linear, phens fed a diet supplemented with increasing levels of R. capsulatus KCTC-2583 had increased (linear; p0.05) on feed intake of laying hens. At d 28 and 56, breaking strength and yolk colour of eggs were linearly improved (phens fed dietary increasing levels of R. capsulatus KCTC-2583. Dietary treatment had no effects (linear or quadratic; p>0.05) on albumin height, shell thickness and shell weight at any period of experiment. These results indicate that dietary supplementation of R. capsulatus KCTC-2583 has the potential to improve the laying hen performance and lead to the development of low cholesterol eggs during late laying period in Hy-Line Brown hens. PMID:25049857

  9. The Effects of Rhodobacter capsulatus KCTC-2583 on Cholesterol Metabolism, Egg Production and Quality Parameters during the Late Laying Periods in Hens.

    Science.gov (United States)

    Lokhande, Anushka; Ingale, S L; Lee, S H; Kim, J S; Lohakare, J D; Chae, B J; Kwon, I K

    2013-06-01

    An experiment was conducted to investigate the effects of dietary supplementation of Rhodobacter capsulatus KCTC-2583 on egg-yolk and serum cholesterol, egg production and quality parameters during the late laying periods in hens. A total of 160 Hy-Line Brown layers (54 wk-old) were randomly allotted to 4 treatment groups on the basis of laying performance. Each treatment had 4 replicates with 10 birds each (40 birds per treatment). Two hens were confined individually with cage size 35×35×40 cm and each 10 birds (5 cages) shared a common feed trough between them forming one experimental unit. Dietary treatments were; basal diet supplemented with 0 (control), 0.05, 0.10 and 0.15% R. capsulatus KCTC-2583. Experimental diets were fed in meal form for 56 d. Dietary supplementation of increasing levels of R. capsulatus KCTC-2583 reduced (linear, phens fed a diet supplemented with increasing levels of R. capsulatus KCTC-2583 had increased (linear; p0.05) on feed intake of laying hens. At d 28 and 56, breaking strength and yolk colour of eggs were linearly improved (phens fed dietary increasing levels of R. capsulatus KCTC-2583. Dietary treatment had no effects (linear or quadratic; p>0.05) on albumin height, shell thickness and shell weight at any period of experiment. These results indicate that dietary supplementation of R. capsulatus KCTC-2583 has the potential to improve the laying hen performance and lead to the development of low cholesterol eggs during late laying period in Hy-Line Brown hens.

  10. Overproduction of CcmG and CcmFHRc Fully Suppresses the c-Type Cytochrome Biogenesis Defect of Rhodobacter capsulatus CcmI-Null Mutants

    Science.gov (United States)

    Sanders, Carsten; Deshmukh, Meenal; Astor, Doniel; Kranz, Robert G.; Daldal, Fevzi

    2005-01-01

    Gram-negative bacteria like Rhodobacter capsulatus use intertwined pathways to carry out the posttranslational maturation of c-type cytochromes (Cyts). This periplasmic process requires at least 10 essential components for apo-Cyt c chaperoning, thio-oxidoreduction, and the delivery of heme and its covalent ligation. One of these components, CcmI (also called CycH), is thought to act as an apo-Cyt c chaperone. In R. capsulatus, CcmI-null mutants are unable to produce c-type Cyts and thus sustain photosynthetic (Ps) growth. Previously, we have shown that overproduction of the putative heme ligation components CcmF and CcmHRc (also called Ccl1 and Ccl2) can partially bypass the function of CcmI on minimal, but not on enriched, media. Here, we demonstrate that either additional overproduction of CcmG (also called HelX) or hyperproduction of CcmF-CcmHRc is needed to completely overcome the role of CcmI during the biogenesis of c-type Cyts on both minimal and enriched media. These findings indicate that, in the absence of CcmI, interactions between the heme ligation and thioreduction pathways become restricted for sufficient Cyt c production. We therefore suggest that CcmI, along with its apo-Cyt chaperoning function, is also critical for the efficacy of holo-Cyt c formation, possibly via its close interactions with other components performing the final heme ligation steps during Cyt c biogenesis. PMID:15937187

  11. Rhodobacter capsulatus nifA1 Promoter: High-GC −10 Regions in High-GC Bacteria and the Basis for Their Transcription

    Science.gov (United States)

    Richard, Cynthia L.; Tandon, Animesh; Kranz, Robert G.

    2004-01-01

    It was previously shown that the Rhodobacter capsulatus NtrC enhancer-binding protein activates the R. capsulatus housekeeping RNA polymerase but not the Escherichia coli RNA polymerase at the nifA1 promoter. We have tested the hypothesis that this activity is due to the high G+C content of the −10 sequence. A comparative analysis of R. capsulatus and other α-proteobacterial promoters with known transcription start sites suggests that the G+C content of the −10 region is higher than that for E. coli. Both in vivo and in vitro results obtained with nifA1 promoters with −10 and/or −35 variations are reported here. A major conclusion of this study is that α-proteobacteria have evolved a promiscuous sigma factor and core RNA polymerase that can transcribe promoters with high-GC −10 regions in addition to the classic E. coli Pribnow box. To facilitate studies of R. capsulatus transcription, we cloned and overexpressed all of the RNA polymerase subunits in E. coli, and these were reconstituted in vitro to form an active, recombinant R. capsulatus RNA polymerase with properties mimicking those of the natural polymerase. Thus, no additional factors from R. capsulatus are necessary for the recognition of high-GC promoters or for activation by R. capsulatus NtrC. The addition of R. capsulatus σ70 to the E. coli core RNA polymerase or the use of −10 promoter mutants did not facilitate R. capsulatus NtrC activation of the nifA1 promoter by the E. coli RNA polymerase. Thus, an additional barrier to activation by R. capsulatus NtrC exists, probably a lack of the proper R. capsulatus NtrC-E. coli RNA polymerase (protein-protein) interaction(s). PMID:14729700

  12. Les Determinants du Desir De Grossesse chez les Femmes Seropositives sous Traitement AntiRetroviral dans le District de Rwamagana

    Directory of Open Access Journals (Sweden)

    Claudien Uwanyirigira

    2013-06-01

    Full Text Available L’étude vise à analyser les déterminants du désir de grossesse chez les femmes séropositives sous traitement anti-retroviral, afin de contribuer à la réduction de la transmission du virus de la mère à l’enfant. Elle a pour objectifs spécifiques de déterminer la proportion des grossesses chez les femmes à sérologie VIH positive, d’évaluer l’attitude du personnel de santé à l’égard des messages à donner aux femmes séropositives sous ARVs en ce qui concerne le désir de la grossesse, et relever les facteurs déterminant le désir d’avoir des enfants après la mise ne route d’un traitement par antirétroviraux . Il s’agit d’une étude descriptive transversale. Elle a été conduite auprès de 260 femmes infectées par le VIH sous ARVs et suivies dans les FOSA, ayant les services de VCT/PMTCT et des ARVs. L’étude montre que 26,9% des femmes ont été enceintes après avoir été informées de leur statut sérologique positif pour le VIH et que 38,5% des femmes séropositives sous traitement anti-rétroviral désirent avoir des enfants dans le futur. La majorité des femmes (82,7% reconnaissent l’importance de l’utilisation des contraceptifs alors que le pourcentage des femmes qui connaissent l’importance d’utiliser les ARVs pendant la grossesse et l’accouchement pour réduire le risque de transmission de la mère à l’enfant est de 76,9%. Les facteurs déterminant le désir de la grossesse parmi les femmes séropositives sont : La confiance attribuée aux anti-rétroviraux, la parité c’est-à-dire les femmes qui n’ont pas eu d’enfant ont un désir de maternité deux fois supérieur que les femmes qui ont eu au moins un enfant, et la non utilisation des méthodes contraceptives chez les femmes à sérologie VIH positives pour réduire le risque de transmission de la mère à l’enfant. Nous recommandons de renforcer l’intégration des activités de santé de la reproduction et de Planning

  13. 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

  14. Valorisation de tourteaux de soja issus d’une production locale non OGM chez les fabricants d’aliments

    Directory of Open Access Journals (Sweden)

    Le Cadre Patricia

    2015-09-01

    Full Text Available L’opportunité de mettre en place une filière française intégrée de la production de graines de soja à l’utilisation du tourteau, est liée à la faisabilité économique de celle-ci et notamment à la valorisation des coproduits. L’étude réalisée à l’échelle territoriale (Sud-Ouest et Rhône Alpes, démontre qu’un tourteau de soja gras local possède de nombreux débouchés rémunérateurs liés ou non, à son caractère non OGM et à son image « terroir » chez les fabricants d’aliments pour animaux de rente. Cela lui confère un intérêt économique face à un tourteau d’importation (standard ou non OGM, qui peut cependant varier en fonction du contexte de prix, mais aussi en fonction des décisions de mise en marché qui seront prises par les opérateurs concernés (contractualisation ou non dans des filières locales de qualité.

  15. Dynamics of Rhodobacter capsulatus [2Fe-2S] Ferredoxin VI and Aquifex aeolicus Ferredoxin 5 Via Nuclear Resonance Vibrational Spectroscopy (NRVS) and Resonance Raman Spectroscopy.

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Yuming; Tan, Ming-Liang; Ichiye, Toshiko; Wang, Hongxin; Guo, Yisong; Smith, Matt C.; Meyer, Jacques; Sturhahn, Wolfgang; Alp, E. E.; Zhao, Jiyong; Yoda, Yoshitaka; Cramer, Stephen P.

    2008-06-24

    We have used (57)Fe nuclear resonance vibrational spectroscopy (NRVS) to study the Fe(2)S(2)(Cys)(4) sites in oxidized and reduced [2Fe-2S] ferredoxins from Rhodobacter capsulatus (Rc FdVI) and Aquifex aeolicus (Aa Fd5). In the oxidized forms, nearly identical NRVS patterns are observed, with strong bands from Fe-S stretching modes peaking around 335 cm(-1), and additional features observed as high as the B(2u) mode at approximately 421 cm(-1). Both forms of Rc FdVI have also been investigated by resonance Raman (RR) spectroscopy. There is good correspondence between NRVS and Raman frequencies, but because of different selection rules, intensities vary dramatically between the two kinds of spectra. For example, the B(3u) mode at approximately 288 cm(-1), attributed to an asymmetric combination of the two FeS(4) breathing modes, is often the strongest resonance Raman feature. In contrast, it is nearly invisible in the NRVS, as there is almost no Fe motion in such FeS(4) breathing. NRVS and RR analysis of isotope shifts with (36)S-substituted into bridging S(2-) ions in Rc FdVI allowed quantitation of S(2-) motion in different normal modes. We observed the symmetric Fe-Fe stretching mode at approximately 190 cm(-1) in both NRVS and RR spectra. At still lower energies, the NRVS presents a complex envelope of bending, torsion, and protein modes, with a maximum at 78 cm(-1). The (57)Fe partial vibrational densities of states (PVDOS) were interpreted by normal-mode analysis with optimization of Urey-Bradley force fields. Progressively more complex D(2h) Fe(2)S(2)S'(4), C(2h) Fe(2)S(2)(SCC)(4), and C(1) Fe(2)S(2)(Cys)(4) models were optimized by comparison with the experimental spectra. After modification of the CHARMM22 all-atom force field by the addition of refined Fe-S force constants, a simulation employing the complete protein structure was used to reproduce the PVDOS, with better results in the low frequency protein mode region. This process was then repeated

  16. 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

  17. Characterization of a nif-regulated flavoprotein (FprA) from Rhodobacter capsulatus. Redox properties and molecular interaction with a [2Fe-2S] ferredoxin.

    Science.gov (United States)

    Jouanneau, Y; Meyer, C; Asso, M; Guigliarelli, B; Willison, J C

    2000-02-01

    A flavoprotein from Rhodobacter capsulatus was purified as a recombinant (His)6-tag fusion from an Escherichia coli clone over-expressing the fprA structural gene. The FprA protein is a homodimer containing one molecule of FMN per 48-kDa monomer. Reduction of the flavoprotein by dithionite showed biphasic kinetics, starting with a fast step of semiquinone (SQ) formation, and followed by a slow reduction of the SQ. This SQ was in the anionic form as shown by EPR and optical spectroscopies. Spectrophotometric titration gave a midpoint redox potential for the oxidized/SQ couple of Em1 = +20 mV (pH 8.0), whereas the SQ/hydroquinone couple could not be titrated due to the thermodynamic instability of SQ associated with its slow reduction process. The inability to detect the intermediate form, SQ, upon oxidative titration confirmed this instability and led to an estimate of Em2 - Em1 of > 80 mV. The reduction of SQ by dithionite was significantly accelerated when the [2Fe-2S] ferredoxin FdIV was used as redox mediator. The midpoint redox potential of this ferredoxin was determined to be -275 +/- 2 mV at pH 7.5, consistent with FdIV serving as electron donor to FprA in vivo. FdIV and FprA were found to cross-react when incubated together with the 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, giving a covalent complex with an Mr of approximately 60 000. Formation of this complex was unaffected by the redox states of the two proteins. Other [2Fe-2S] ferredoxins, including FdV and FdVI from R. capsulatus, were ineffective as electron carriers to FprA, and cross-reacted poorly with the flavoprotein. The possible function of FprA with regard to nitrogen fixation was investigated using an fprA-deleted mutant. Although nitrogenase activity was significantly reduced in the mutant compared with the wild-type strain, nitrogen fixation was apparently unaffected by the fprA deletion even under iron limitation or microaerobic conditions.

  18. Nucleotide sequence and genetic analysis of the Rhodobacter capsulatus ORF6-nifUI SVW gene region: possible role of NifW in homocitrate processing.

    Science.gov (United States)

    Masepohl, B; Angermüller, S; Hennecke, S; Hübner, P; Moreno-Vivian, C; Klipp, W

    1993-04-01

    DNA sequence analysis of a 3494-bp HindIII-BclI fragment of the Rhodobacter capsulatus nif region A revealed genes that are homologous to ORF6, nifU, nifS, nifV and nifW from Azotobacter vinelandii and Klebsiella pneumoniae. R. capsulatus nifU, which is present in two copies, encodes a novel type of NifU protein. The deduced amino acid sequences of NifUI and NifUII share homology only with the C-terminal domain of NifU from A. vinelandii and K. pneumoniae. In contrast to nifA and nifB, which are almost perfectly duplicated, the predicted amino acid sequences of the two NifU proteins showed only 39% sequence identity. Expression of the ORF6-nifUISVW operon, which is preceded by a putative sigma 54-dependent promoter, required the function of NifA and the nif-specific rpoN gene product encoded by nifR4. Analysis of defined insertion and deletion mutants demonstrated that only nifS was absolutely essential for nitrogen fixation in R. capsulatus. Strains carrying mutations in nifV were capable of very slow diazotrophic growth, whereas ORF6, nifUI and nifW mutants as well as a nifUI/nifUII double mutant exhibited a Nif+ phenotype. Interestingly, R. capsulatus nifV mutants were able to reduce acetylene not only to ethylene but also to ethane under conditions preventing the expression of the alternative nitrogenase system. Homocitrate added to the growth medium repressed ethane formation and cured the NifV phenotype in R. capsulatus. Higher concentrations of homocitrate were necessary to complement the NifV phenotype of a polar nifV mutant (NifV-NifW-), indicating a possible role of NifW either in homocitrate transport or in the incorporation of this compound into the iron-molybdenum cofactor of nitrogenase. PMID:8492805

  19. Evaluation de la fonction hépatique au cours du paludisme grave chez les enfants de moins de cinq ans à Kinshasa en République Démocratique du Congo

    Science.gov (United States)

    Kabamba, Arsène Tshikongo; Mukuku, Olivier; Shamashanga, Laurent Kwete; Kamunga, Daniel Badibanga; Bokanya, Alex Impele; Lukumwena, Zet Kalala; Longanga, Albert Otshudi

    2014-01-01

    Introduction Le paludisme est toujours compté parmi les problèmes de santé publique prioritaires en République Démocratique du Congo suite au nombre de malades et de décès qu'il provoque. Cette étude évalue l'atteinte de la fonction hépatique au cours du paludisme grave chez les enfants de moins de 5 ans. Méthodes Il s'agit d'une étude cas-témoins menée de janvier à juin 2013 à Kinshasa (République Démocratique du Congo) où le dosage des bilirubines totale, directe et indirecte et la mesure de l'activité enzymatique de la Glutamate Pyruvate Transaminase (GPT), de la Glutamate Oxaloacétate Transaminase (GOT) et du taux d'hémoglobine ont été faits chez 46 enfants âgés de moins de 5 ans atteints de paludisme grave (groupe I) et chez 46 autres considérés sains avec une goutte négative (groupe II). Les résultats obtenus ont été comparés dans les deux groupes et le seuil de signification a été fixé à p bilirubine directe, la bilirubine indirecte et la bilirubine totale chez les enfants atteints du paludisme grave. Ces analyses montrent une différence significative en défaveur de ces derniers (p < 0,001). Conclusion En effet, cette augmentation des taux plasmatiques des paramètres biologiques analysés observée chez les enfants gravement impaludés traduit ainsi une altération de la fonction hépatique au cours d'un paludisme grave chez l'enfant de moins de cinq ans. PMID:25870721

  20. Effect of Spray Freeze Drying on Antioxidant Activity of Phycocyprotein from Nostoc sphaeroides KUting%喷雾冷冻干燥对葛仙米藻胆蛋白抗氧化特性的影响

    Institute of Scientific and Technical Information of China (English)

    程超; 朱玉婷; 田瑞; 汪兴平; 潘思轶

    2012-01-01

    研究喷雾冷冻干燥对葛仙米藻胆蛋白抗氧化特性的影响,并与冷冻干燥技术进行比较。主要测定ABTS+·、铁还原抗氧化能力(FRAP)、对羟自由基(·OH)清除作用和H2O2诱导的脂质过氧化的抑制作用,结果发现,喷雾冷冻干燥(SFD)对葛仙米藻胆蛋白的抗氧化特性有一定的影响,在基于电子转移和氢原子转移的抗氧化测定方法中,SFD与冷冻干燥(FD)制备的样品差异不明显,但在基于活性氧自由基清除的测定方法中,SFD显著优于FD。表明SFD非常适合于高活性成分的干燥。%In this study, the effect of spray freeze drying on the antioxidant activity of phycobiliprotein fromNostoc sphaeroides KUting was studied and compared with that of common freeze drying. The scavenging effect of phycobiliprotein on ABTS+· and hydroxyl radicals (·OH), H2O2-induced lipid peroxidation and ferric-ion reducing power (FRAP) were evaluated. The results indicated that spray freeze drying method had obvious effect on antioxidant activity of phycobiliprotein from Nostoc sphaeroides Kuting. The samples dried by two different methods showed no significant difference in the antioxidant activity determined based on electron transfer and hydrogen atom transfer. The free radical scavenging activity of the sample dried by spray freeze drying method was markedly higher than that of the sample dried by common freeze drying method. These data suggest that spray freeze drying is more suitable for drying active substances.

  1. Représentations du rébétiko chez les élites intellectuelles de gauche entre la guerre civile et la dictature des colonels

    OpenAIRE

    Alexopoulos, Christina

    2016-01-01

    Les représentations du rébétiko chez les élites intellectuelles de gauche entre la guerre civile et la dictature sont ambivalentes. Si quelques voix minoritaires mettent en avant l’intérêt musical du genre, la plupart des intellectuels de gauche s’attardent sur ses thématiques pour stigmatiser son manque de combativité, son fatalisme, son apologie de la drogue et de la pornographie, signes selon elles d’une appartenance au lumpenprolétariat ou aux forces réactionnaires. Cette vision, dominant...

  2. La violence amoureuse dans les relations amoureuses chez les adolescents: comment aider les jeunes victimes institutionnalisées à se reconstruire?

    OpenAIRE

    Délèze, Aurélie; Jaggi, Jennifer; Lorenz, Susanne

    2012-01-01

    De nos jours, la violence dans les relations amoureuses chez les adolescents est un sujet tabou, voire effrayant. Les adolescents ont une propension de plus en plus forte à l’agressivité, notamment de par ce qui leur est transmis par le biais et au travers des médias, des jeux vidéo, etc. De ce fait, leurs relations interpersonnelles s’en trouvent passablement influencées et, conséquemment, perturbées. Ces raisons impliquent que les professionnels ont de la difficulté à mettre en place des st...

  3. Les hormones thyroïdiennes, leurs récepteurs et l'évolution de la métamorphose chez les Chordés.

    OpenAIRE

    Paris, Mathilde

    2008-01-01

    DANS L'ETUDE DES PROCESSI D'EVOLUTION DU DEVELOPPEMENT, LES FACTEURS DE TRANSCRIPTION SONT IMPORTANTS CAR ILS REGULENT L'EXPRESSION GENIQUE AU COURS DU DEVELOPPEMENT. PARMI CES FACTEURS, LES RECEPTEURS NUCLEAIRES (RNS) ONT UN STATUT PARTICULIER CAR LEUR ACTIVITE EST REGULEE PAR UN LIGAND. DURANT MA THESE, JE ME SUIS INTERESSEE A L'EVOLUTION DES RNS CHEZ LES CHORDES (TELS QUE LES VERTEBRES, LES TUNICIES ET L'AMPHIOXUS) EN ETUDIANT DEUX RNS PARTICULIERS : LES RECEPTEURS AUX OESTROGENES (ER) ET ...

  4. Traitement hormonal de la ménopause et risque de diabète chez les femmes de la cohorte E3N

    OpenAIRE

    de Lauzon-Guillain, Blandine; Fournier, Agnès; Fabre, Alban; Simon, Nicolas; Mesrine, Sylvie; Boutron-Ruault, Marie-Christine; Balkau, Beverley; Clavel-Chapelon, Françoise

    2009-01-01

    International audience Deux essais randomisés américains ont mis en évidence une diminution du risque de diabète chez les femmes qui prenaient un traitement hormonal de la ménopause. L'objectif de ce projet est de voir si ces résultats sont applicables à la population française, où les traitements sont différents de ceux utilisés aux États-Unis

  5. Les biotechnologies de la reproduction chez les bovins et leurs applications réelles ou potentielles en sélection

    OpenAIRE

    Colleau, J Jacques; Heyman, Y; Renard, Jean Paul

    1998-01-01

    Cet article décrit les bases de plusieurs biotechnologies de la reproduction chez les bovins : superovulation et transplantation embryonnaire, sexage des embryons, ponction des ovocytes in vivo et fécondation in vitro, clonage embryonnaire et clonage somatique. On précise leurs limites techniques actuelles, leurs perspectives d’amélioration et leurs coûts respectifs. Les conséquences de leur utilisation dans les programmes d’amélioration génétique sont analysées tant au niveau de la situation...

  6. 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

  7. Génomique comparative des bactéries Dickeya solani et Pectobacterium wasabiae, pathogènes émergents chez Solanum tuberosum

    OpenAIRE

    Khayi, Slimane

    2015-01-01

    Les bactéries pectinolytiques appartenant aux genres Pectobacterium et Dickeya spp. sont des agents pathogènes chez Solanum tuberosum. Ces bactéries sont responsables de la maladie de la jambe noire et de la pourriture molle lors de la culture et du stockage des tubercules. Ce travail de thèse est divisé en deux axes: 1) Etude dela diversité d'une population du pathogène D. solani par approche de génomique comparée afin de mieux comprendre la structure génomique de cette espèce émergente. 2) ...

  8. Manifestations cliniques et endocrines liées au stress chez le chien et le chat : étude bibliographique comparative

    OpenAIRE

    Lapeyrade, Elsa

    2014-01-01

    Ce travail est une étude bibliographique comparative ayant pour but de décrire les manifestations cliniques et endocrines liées au stress chez le chien et le chat, et de pouvoir ainsi orienter les vétérinaires praticiens dans l’interprétation des résultats obtenus lors de modifications cliniques mais aussi physiopathologiques qui comprennent entre autres les mesures hormonales, biochimiques et hématologiques. Selon la chronicité du stimulus, le système nerveux orthosympathique via les catécho...

  9. Vignette thérapeutique de l'étudiant. Quelles cibles tensionnelles viser chez un patient diabétique de type 2?

    OpenAIRE

    Krzesinski, Jean-Marie; Scheen, André

    2012-01-01

    L'hypertension artérielle est fréquemment observée chez le patient diabétique de type 2 et aggrave le pronostic cardio-vasculaire et rénal. Abaisser la pression artérielle représente donc un objectif essentiel dans cette population. Cependant, les valeurs de pression systolique et diastolique à atteindre restent controversées et la cible doit sans doute être ajustée en fonction des caractéristiques individuelles du patient ("médecine personnalisée"). Cette vignette clinique résume les princip...

  10. Troubles du sommeil chez les enfants présentant un Trouble Déficit d'Attention avec/sans Hyperactivité: analyse polysomnographique et spectrale

    OpenAIRE

    Ditisheim, Saskia Isabel; Haenggeli, Charles-Antoine; Sforza, Emilia

    2008-01-01

    Les enfants avec un Trouble Déficit d'Attention avec/sans Hyperactivité (TDAH) peuvent rapporter différents troubles subjectifs du sommeil. Cependant, il n'existe pas dans la littérature de données décrivant des modifications objectives de la structure du sommeil. Etant donné que l'analyse spectrale de l'EEG de veille a montré des anomalies spectrales chez ces enfants, nous avons étudié par analyse spectrale l'EEG de sommeil et exploré topographiquement ces modifications afin de déterminer si...

  11. Troubles du sommeil chez les enfants présentant un Trouble Déficit d'Attention avec/sans Hyperactivité : analyse polysomnographique et spectrale

    OpenAIRE

    Ditisheim, Saskia Isabel

    2007-01-01

    Les enfants avec un Trouble Déficit d'Attention avec/sans Hyperactivité (TDAH) peuvent rapporter différents troubles subjectifs du sommeil. Cependant, il n'existe pas dans la littérature de données décrivant des modifications objectives de la structure du sommeil. Etant donné que l'analyse spectrale de l'EEG de veille a montré des anomalies spectrales chez ces enfants, nous avons étudié par analyse spectrale l'EEG de sommeil et exploré topographiquement ces modifications afin de déterminer si...

  12. Effets du régime cafeteria sur les marqueurs du statut oxyqanII antioxydant (sang, foie, muscle) chez la rate wistar au &de la ' gestation.

    OpenAIRE

    ATTARI, Faiza

    2014-01-01

    Résumé: Une suralimentation prolongée provoque une obésité avec installation des troubles K ' métaboliques. Le but de ce travail est de déterminer les effets du régime cafeteria, un régime hyperlipidique et hypercalorique, sur le métabolisme des lipides, des glucides et le statut oxydant/ antioxydant chez la rate pendant la gestation. Le régime cafeteria induit une obésité suite à une hyperphagie, associée à une augmentation du tissu adipeux, à une hyperglycémie, et une hype...

  13. Épistémologie de la biologie et conceptualisation du vivant chez des futurs enseignants et biologistes

    Directory of Open Access Journals (Sweden)

    Simard Catherine

    2015-01-01

    Full Text Available L’ensemble des résultats présentés dans cet article relève d’une étude doctorale qui s’est intéressée à l’histoire de la biologie et aux grandes conceptions qui ont alimenté la construction des savoirs en biologie jusqu’à présent (Simard, 2015 [1]. À cet égard, un ensemble de conceptions du vivant a été sélectionné et circonscrit afin de développer un nouvel outil d’évaluation estimant la présence de l’une ou l’autre de ces conceptions chez les futurs enseignants et biologistes. Pour certaines conceptions s’avérant désuètes, la problématique est qu’elles se voient reconduites, encore aujourd’hui, dans la pensée scientifique. C’est alors en termes d’obstacle épistémologique historique à une conceptualisation contemporaine du vivant qu’elles sont appréhendées. Cette caractérisation de la conceptualisation du vivant et l’identification de conceptionsobstacles sont un passage nécessaire afin d’étudier, ultérieurement, les processus d’apprentissage et l’élaboration de séquences didactiques en les considérant au profit d’une compréhension actuelle du vivant. Enfin, est présentée brièvement l’influence positive que peut avoir une formation scientifique en biologie sur la conceptualisation du vivant et sur les conceptions-obstacles, qui se voient alors décliner*.

  14. 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).

  15. Comparative Study of Spectral Flexibilities of Bacterial Light-Harvesting Complexes: Structural Implications

    Science.gov (United States)

    Rutkauskas, Danielis; Olsen, John; Gall, Andrew; Cogdell, Richard J.; Hunter, C. Neil; van Grondelle, Rienk

    2006-01-01

    This work presents a comparative study of the frequencies of spectral jumping of individual light-harvesting complexes of six different types: LH2 of Rhodopseudomonas acidophila, Rhodobacter sphaeroides, and Rhodospirillum molischianum; LH1 of Rhodobacter sphaeroides; and two “domain swap mutants” of LH2 of Rhodobacter sphaeroides: PACLH1 and PACLH2mol, in which the α-polypeptide C-terminus is exchanged with the corresponding sequence from LH1 of Rhodobacter sphaeroides or LH2 of Rhodospirillum molischianum, respectively. The quasistable states of fluorescence peak wavelength that were previously observed for the LH2 of Rps. acidophila were confirmed for other species. We also observed occurrences of extremely blue-shifted spectra, which were associated with reversible bleaching of one of the chromophore rings. Different jumping behavior is observed for single complexes of different types investigated with the same equivalent excitation intensity. The differences in spectral diffusion are associated with subtle differences of the binding pocket of B850 pigments and the structural flexibility of the different types of complexes. PMID:16399835

  16. GenBank blastx search result: AK061856 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK061856 001-040-G03 AF018073.1 Rhodobacter sphaeroides operon regulator (smoC), periplasmic sorbitol...-binding protein (smoE), sorbitol/mannitol transport inner membrane protein (smoF), sorbitol.../mannitol transport inner membrane protein (smoG), sorbitol/mannitol transport ATP-binding transport protein (smoK), sorbitol

  17. Continuous Cultivation of Photosynthetic Bacteria for Fatty Acids Production

    DEFF Research Database (Denmark)

    Kim, Dong-Hoon; Lee, Ji-Hye; Hwang, Yuhoon;

    2013-01-01

    In the present work, we introduced a novel approach for microbial fatty acids (FA) production. Photosynthetic bacteria, Rhodobacter sphaeroides KD131, were cultivated in a continuous-flow, stirred-tank reactor (CFSTR) at various substrate (lactate) concentrations.At hydraulic retention time (HRT)...

  18. Conformational regulation of charge recombination reactions in a photosynthetic bacterial reaction center

    DEFF Research Database (Denmark)

    Katona, Gergely; Snijder, Arjan; Gourdon, Pontus Emanuel;

    2005-01-01

    In bright light the photosynthetic reaction center (RC) of Rhodobacter sphaeroides stabilizes the P(+)(870).Q(-)(A) charge-separated state and thereby minimizes the potentially harmful effects of light saturation. Using X-ray diffraction we report a conformational change that occurs within the cy...

  19. GenBank blastx search result: AK111944 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK111944 001-022-C09 AF016236.1 Rhodobacter sphaeroides DMSO/TMAO-sensor kinase (dorS), DMSO.../TMAO-response regulator (dorR), DMSO/TMAO-cytochrome c-containing subunit (dorC), DMSO-membrane protein (dorB), and DMSO

  20. Deactivation of excitation energy in bacterial photosynthetic reaction centres in Langmuir-Blodgett films

    Science.gov (United States)

    Miyake, J.; Hara, M.; Goc, J.; Planner, A.; Wróbel, D.

    1997-08-01

    Absorption, photoacoustic and time-resolved in μs time range delayed luminescence spectra have been measured in order to follow the interaction among chromophores when Rhodobacter sphaeroides and Rhodopseudomonas viridis reaction centres are closely packed in a form of Langmuir-Blodgett multilayers. Two types of Langmuir-Blodgett samples have been prepared and investigated: multilayers consist of one type of reaction centre ( Rhodobacter sphaeroides or Rhodopseudomonas viridis) and multilayers composed of mixed reaction centres ( Rhodobacter sphaeroides mixed with Rhodopseudomonas viridis). Using the Langmuir-Blodgett multilayers composed of two types of bacteria reaction centres mixture, we were able to extend the spectral region of the light/solar energy absorbed by the system. It was shown that each form of pigment participates in thermal dissipation but to a different degree. A special pair (bacteriochlorophyll dimer) does not contribute to delayed luminescence. Delayed luminescence in Rhodopseudomonas viridis and Rhodobacter sphaeroides differs very significantly from each other. Bacteriopheophytin as well as dihydromesochlorophyll contribute to delayed luminescence but the degree of their participation in this radiative process depends strongly on the type of reaction centre. Delayed luminescence and thermal processes have been indicated as important processes of deactivation of the photoexcited chromophores in reaction centres.

  1. GenBank blastx search result: AK243491 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243491 J100073O14 M86823.1 RCANIFA Rhodobacter sphaeroides ORF1, complete cds; nif...U gene, complete cds; nifS gene, complete cds; nifV gene, complete cds; nifW gene, complete cds; rponN gene, partial cds. BCT 2e-36 1 ...

  2. GenBank blastx search result: AK287500 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK287500 J043034C21 M86823.1 RCANIFA Rhodobacter sphaeroides ORF1, complete cds; nifU gene, complete... cds; nifS gene, complete cds; nifV gene, complete cds; nifW gene, complete cds; rponN gene, partial cds. BCT 7e-11 0 ...

  3. GenBank blastx search result: AK058791 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK058791 001-002-F06 M86823.1 Rhodobacter sphaeroides ORF1, complete cds; nifU gene, complete... cds; nifS gene, complete cds; nifV gene, complete cds; nifW gene, complete cds; rponN gene, partial cds.|BCT BCT 3e-13 +3 ...

  4. GenBank blastx search result: AK059171 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK059171 001-023-F01 M86823.1 Rhodobacter sphaeroides ORF1, complete cds; nifU gene, complete... cds; nifS gene, complete cds; nifV gene, complete cds; nifW gene, complete cds; rponN gene, partial cds.|BCT BCT 2e-66 +3 ...

  5. Description de la fatigue chez les proches-aidants d'un parent atteint de troubles cognitifs

    Directory of Open Access Journals (Sweden)

    Yvanne Brousseau

    2010-01-01

    Full Text Available Attribué aux familles depuis plusieurs décennies, le rôle de proche-aidant est largement reconnu socialement. Il apparaît impossible de maintenir dans la communauté une personne atteinte de troubles cognitifs sans le soutien et l’aide apportés par un membre de la famille. Cependant, un nombre considérable de proches-aidants souffrent de fatigue persistante directement reliée à leur rôle d’aidant. Afin de mieux comprendre le phénomène de la fatigue, cette étude pilote propose de décrire la fatigue d’un groupe de proches-aidants prenant soin d’un parent atteint de troubles cognitifs. À l’aide de l’échelle de fatigue de PIper, nous avons mesuré les dimensions comportementale, affective, sensorielle et cognitive auprès de 23 proches-aidants de la région du Bas-Saint-Laurent et de la Gaspésie. Cet instrument comprend aussi cinq questions ouvertes permettant de décrire la perception de la fatigue chez les participants. Les résultats démontrent un niveau de fatigue global modéré (M = 5,4, ÉT = 2,08 avec une moyenne plus élevée (M = 6,7, ÉT = 2,18 pour la dimension affective, M=10 étant le résultat maximal. La majorité des répondants (97% ont mentionné ressentir une fatigue et parmi eux, 87 % mentionnent leur rôle comme en étant la cause directe, dont les manifestions incluent l’insomnie et le manque d’appétit. De plus, plusieurs rapportent des sentiments tels la peur, l’inquiétude, la culpabilité et l’incompréhension par rapport à leur proche, accentuant la perception de fatigue. Ces résultats soulignent l’importance d’un soutien dans le rôle de proche-aidant afin de favoriser le maintien à domicile du parent atteint de troubles cognitifs.

  6. « 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 ».

  7. Flux géniques et dispersion chez un rongeur à démographie cyclique dans un paysage agricole intensif

    OpenAIRE

    Gauffre, Bertrant

    2009-01-01

    La dispersion est un trait d'histoire de vie qui joue un rôle majeur dans le fonctionnement des populations naturelles. Comprendre ce phénomène et son évolution est aujourd'hui déterminant pour la gestion des populations dans des écosystèmes de plus en plus anthropisés. Cette étude s'est attachée à caractériser la dispersion et ses déterminants chez le campagnol des champs, Microtus avalis, dans un paysage agricole de l'Ouest de la France. L'instabilité spatio-temporelle des agroécosystèmes e...

  8. La réplication de l'ADN chez l'euryarchaea Pyrococcus Abyssi : mise en place et dynamique du complexe

    OpenAIRE

    Rouillon, Christophe

    2006-01-01

    La replication de l'ADN se fait par le biais d'un complexe protéique appelé réplisome. La compréhension des aspects structuraux et dynamiques nécessite sa reconstitution in vitro à partir des sous-unités individuelles. Chez tous les organismes vivants, la phase d'élongation de l'ADN, effectuée par les ADN polymérases, met en jeu un facteur de processivité (PCNA) qui est chargé sur l'ADN par un facteur de chargement (RF-C). Généralement, les protéines des archées, impliquées dans la réplicatio...

  9. Méta-analyses des effets chimioprotecteurs de la curcumine et du thé vert sur la cancérogenèse colorectale chez les rongeurs

    OpenAIRE

    Clauzure, Cédric

    2007-01-01

    L'étude de l'effet chimioprotecteur, chez les rongeurs, de la curcumine et du thé vert contre le cancer du côlon est l'objet de plusieurs publications. Mais il en ressort des résultats contradictoires. Après des rappels bibliographiques sur le cancer du côlon, les polyphénols et la technique méta-analytique, l'auteur réalise des méta-analyses à partir de 15 articles pour la curcumine et de 17 pour le thé vert. Il apparaît que la curcumine diminue significativement le nombre de foyers de crypt...

  10. 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.

  11. Contribution à l’étude de la morphologie et du développement de l’encéphale, en particulier du cervelet, chez le mouton

    OpenAIRE

    Salouci, Moustafa

    2016-01-01

    De nombreuses maladies virales émergentes chez le mouton génèrent des anomalies congénitales au niveau du système nerveux central (SNC), or, peu d'informations sont disponibles dans la littérature sur l’anatomie et le développement du cerveau du mouton, en particulier en ce qui concerne le cervelet. Par ailleurs, il s’avère que le mouton pourrait représenter un bon modèle expérimental animal pour l’étude de certaines pathologies survenant pendant le développement embryonnaire de l’encéphale. ...

  12. Etude du métabolisme des amines biogènes chez les bactéries lactiques du vin

    OpenAIRE

    Bonnin-Jusserand, Maryse

    2011-01-01

    Les amines biogènes sont des composés allergènes, notamment rencontrés dans les produits fermentés tel que le vin. Les bactéries lactiques du vin, dont Oenococcus oeni, le principal acteur de la fermentation malolactique, sont capables de produire ces molécules, à partir de précurseurs azotés. Afin de réduire la teneur en amines biogènes, il est nécessaire de comprendre le rôle de cette production, chez les souches impliquées dans la synthèse de ces métabolites. Le projet européen BiamFood FP...

  13. Rôle de l'inhibition intra- et inter-glomérulaire dans la synchronisation neuronale et le codage phéromonal chez manduca sexta

    OpenAIRE

    Belmabrouk, Hana; Rospars, Jean-Pierre; Ezzine, Jelel; Martinez, Dominique

    2008-01-01

    ISBN : 978-2-9532965-0-1; Une synchronisation neuronale est observée dès le premier étage de traitement du système olfactif, à savoir le lobe antennaire chez l'insecte. Dans le cas du papillon de nuit Manduca sexta, cette synchronisation est plus importante en présence du mélange phéromonal qu'en présence d'un composé simple. Dans cet article, nous proposons un modèle du complexe macroglomérulaire qui reproduit les données expérimentales et permet de mettre en lumière le rôle de l'inhibition ...

  14. Aspects moléculaires et biochimiques des stylicines, peptides multifonctionnels identifiés chez la crevette bleue du Pacifique Litopenaeus stylirostris (Crustacea, Decapoda)

    OpenAIRE

    Rolland, Jean-Luc

    2010-01-01

    Les travaux présentés dans ce mémoire ont été motivés par l’importance économique de l’élevage de la crevette bleue du pacifique Litopenaeus stylirostris dont les fortes mortalités sont principalement dues au développement de maladies bactériennes et virales. Ils ont consisté en la caractérisation des deux premiers membres d’une famille originale de peptides multifonctionnels présents chez les crevettes pénéides, les stylicines. Ces peptides, nommés stylicines 1 et 2, sont des peptides anioni...

  15. Role de la position de la feuille dans l'assimilation et le transport du carbone chez le trefle blanc (Trifolium repens L.)

    OpenAIRE

    Robin, C.; Chone, T.; GUCKERT, Armand

    1987-01-01

    L’étude de l’assimilation photosynthétique et du transport des assimilats chez le trèfle blanc a pour objet de préciser le rôle de la feuille dans l’établissement des relations source-puits. Des marquages courts au 14CO2 sont effectués sur les 8 limbes initiés par le stolon obtenu en conditions contrôlées par bouturage d’apex. Le profil photosynthétique de l’ensemble des limbes du stolon met en évidence un effet « âge du limbe source» pour l’assimilation du 14CO2. Les limbes 2, 3 et 4 son...

  16. Obstacles à la prévention du VIH/SIDA chez les populations migrantes d'origine sub-saharienne: Travail de Bachelor

    OpenAIRE

    Graff, Alexandre; Rappazzo, Barbara; Salsac, Olivier

    2013-01-01

    Contexte : 68% des personnes atteintes du VIH/SIDA dans le monde proviennent d’Afrique sub-saharienne. En Suisse une personne migrante d’origine sub-saharienne a 20,5 fois plus de risque d’être infectée par cette maladie qu’une personne autochtone. But : l’objectif de cette revue de littérature est d’identifier les obstacles à la prévention et au dépistage du VIH/SIDA chez les populations migrantes d’origine sub-saharienne et dégager des pistes d’intervention pour la discipline infirmière. Mé...

  17. Contribution à l'étude de l'anatomie fonctionnelle de l'oreille et de la surdité chez les carnivores domestiques

    OpenAIRE

    Simeon, Ludovic

    2003-01-01

    L'étude de la surdité chez les Carnivores domestiques est, à l'heure actuelle, une pathologie peu décrite en médecine vétérinaire. Ainsi, ce travail constitue une synthèse bibliographique des données disponibles sur ce thème en médecine vétérinaire (et parfois en médecine de l'homme). En effet, pour pouvoir, par la suite, bien appréhender les mécanismes pathologiques de la surdité, la première partie de ce travail est consacrée aux bases anatomiques (embryologie comprise) et physiologiques...

  18. Prévention des déficiences nutritionnelles chez les personnes sans-abri : intérêt d’un aliment de rue enrichi

    OpenAIRE

    Darmon, Nicole; Briend, André

    2006-01-01

    Pour mieux prévenir la dénutrition et les déficiences vitaminiques et minérales chez les personnes en situation d’exclusion, nous avons mis au point un aliment enrichi facile à consommer dans la rue : le Vitapoche®. Il s’agit d’une pâte chocolatée résistante à la contamination bactérienne, emballée dans un sachet hermétique. Cette pâte est naturellement riche en potassium et en acides gras oméga-3. Elle a été enrichie en calcium, zinc et vitamines C, B1, B9, PP, B12, E et D, afin que chaque s...

  19. 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...

  20. Étude descriptive de la prise en charge des anomalies de la phase de latence chez la primipare dans trois maternités d'Auvergne‎

    OpenAIRE

    Boeufgras, Gaëlle

    2014-01-01

    Les anomalies de la phase de latence (dystocie de démarrage et faux travail d'accouchement) sont fréquentes, en particulier chez la primipare. Leur prise en charge est néanmoins délicate et varie d'une maternité à l'autre, en l'absence de recommandations précises sur le sujet. L'étude avait pour objectif de décrire la prise en charge (PEC) des patientes consultant pour contractions utérines régulières et douloureuses sans modification du col, dans 3 maternités d'Auvergne de niveaux différents...

  1. Etude comparative de la tomodensitométrie et de l’imagerie par résonance magnétique dans le diagnostic des tumeurs intracrâniennes chez le chien et le chat

    OpenAIRE

    Dangy, Louise

    2012-01-01

    Les techniques d’imagerie médicale modernes sont utilisées dans l’exploration des affections intracrâniennes chez l’homme et se développent en médecine vétérinaire. Malgré des inégalités d’accès dues au manque d’infrastructures et au coût élevé de réalisation de ces examens, la tomodensitométrie et l’imagerie par résonance magnétique (IRM) sont devenues les examens complémentaires de choix lors de troubles neurologiques d’origine centrale intracrânienne chez le chien et le chat. Si la tomoden...

  2. Evaluation du probiotique bactérien Pediococcus acidilactici MA18/5M chez la crevette pénéide Litopenaeus stylirostris en Nouvelle- Calédonie

    OpenAIRE

    Castex, Mathieu

    2009-01-01

    Pediococcus acidilacticii MA18/5M est un probiotique bactérien (BACTOCELL®) qui a démontré son efficacité chez plusieurs espèces d'animaux terrestres et aquatiques. Cette thèse avait pour objectif d'investiguer plus en détails les effets de ce probiotique chez les crevettes pénéides d'élevage. Pour cette étude, nous avons choisi une approche globale replaçant la problématique dans un modèle d'interactions entre trois compartiments : la crevette, sa microflore intestinale et le probiotique. Ap...

  3. Modifications dans les premières étapes de l'assimilation photosynthétique du carbone chez le maïs sous l'effet du génotype

    OpenAIRE

    Morot-Gaudry, Jean-Francois; Farineau, J.; Rocher, J.P.; Jolivet, E.

    1981-01-01

    L’étude des réactions de carboxylations photosynthétiques chez les maïs « WH x WJ » et « INRA 508 » montre qu’une baisse de l’activité photosynthétique chez le maïs « WH x WJ », par rapport au maïs « INRA 508 », s’accompagne de déviations métaboliques au sein des premières réactions qui assurent le transfert du carbone du CO2 atmosphérique vers les composés du cycle de CALVIN-BENSON, via les acides malique et aspartique. Le même comportement métabolique en relation avec la photosynthèse...

  4. Des lieux de soins alternatifs où se construisent des altérités communes représentations de la maladie et du traitement chez les guérisseurs citadins et leurs patients en Russie

    OpenAIRE

    Khaskelberg, Maria

    2012-01-01

    Le présent travail vise à étudier les représentations de la maladie chez les guérisseurs citadins et chez leurs patients en Russie, aussi bien par le biais d’entretiens semi-directifs que par nos propres observations des pratiques de guérison. L’étonnante popularité présentée par le recours aux soins alternatifs en Russie postsoviétique nous a motivée à nous questionner quant à leurs fonctions dans une société en pleine mutation socio-économique. L'aperçu de la littérature locale sur le trava...

  5. Open reading frame 5 (ORF5), encoding a ferredoxinlike protein, and nifQ are cotranscribed with nifE, nifN, nifX, and ORF4 in Rhodobacter capsulatus.

    Science.gov (United States)

    Moreno-Vivian, C; Hennecke, S; Pühler, A; Klipp, W

    1989-05-01

    DNA sequence analysis of a 1,600-base-pair fragment located downstream of nifENX in nif region A of Rhodobacter capsulatus revealed two additional open reading frames (ORFs): ORF5, encoding a ferredoxinlike protein, and nifQ. The ferredoxinlike gene product contained two cysteine motifs, typical of ferredoxins coordinating two 4Fe-4S clusters, but the distance between these two motifs was unusual for low-molecular-weight ferredoxins. The R. capsulatus nifQ gene product shared a high degree of homology with Klebsiella pneumoniae and Azotobacter vinelandii NifQ, including a typical cysteine motif located in the C-terminal part. nifQ insertion mutants and also an ORF5-nifQ double deletion mutant showed normal diazotrophic growth only in the presence of high concentrations of molybdate. This demonstrated that the gene encoding the ferredoxinlike protein is not essential for nitrogen fixation. No NifA-activated consensus promoter could be found in the intergenic region between nifENX-ORF4 and ORF5-nifQ. Analyses of a nifQ-lacZYA fusion revealed that transcription of nifQ was initiated at a promoter in front of nifE. In contrast to other nitrogen-fixing organisms, R. capsulatus nifE, nifN, nifX, ORF4, ORF5, and nifQ were organized in one transcriptional unit. PMID:2708314

  6. 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

    OpenAIRE

    Julia Woodhall-Melnik; Vachan Misir; Vered Kaufman-Shriqui; Patricia O'Campo; Vicky Stergiopoulos; Stephen Hwang

    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...

  7. Effet du numéro d'oestrus et du nombre de jours après le vêlage sur la probabilité de conception chez les vaches laitières

    DEFF Research Database (Denmark)

    Friggens, Nic; Labouriau, Rodrigo

    2007-01-01

    Pour résoudre les problèmes actuels de reproduction chez les vaches laitières, une meilleure connaissance des facteurs animaux impliqués dans l'élaboration de la performance est nécessaire. Un intérêt particulier est porté sur l'accroissement du taux de conception qui est observé avec le numéro d...

  8. 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.

  9. On Time chez Dummett

    OpenAIRE

    Butterfield, Jeremy

    2012-01-01

    I discuss three connections between Dummett’s writings about time and philosophical aspects of physics. Th e first connection (Section 2) arises from remarks of Dummett’s about the different relations of observation to time and to space. The main point is uncontroversial and applies equally to classical and quantum physics. It concerns the fact that perceptual processing is so rapid, compared with the typical time-scale on which macroscopic objects change their observable properties, that it ...

  10. On Time chez Dummett

    CERN Document Server

    Butterfield, Jeremy

    2014-01-01

    I discuss three connections between Dummett's writings about time and philosophical aspects of physics. The first connection (Section 2) arises from remarks of Dummett's about the different relations of observation to time and to space. The main point is uncontroversial and applies equally to classical and quantum physics. It concerns the fact that perceptual processing is so rapid, compared with the typical time-scale on which macroscopic objects change their observable properties, that it engenders the idea of a 'common now', spread across space. The other two connections are specific to quantum theory, as interpreted along the lines of Everett. So for these two connections, the physics side is controversial, just as the philosophical side is. In Section 3, I connect the subjective uncertainty before an Everettian 'splitting' of the multiverse to Dummett's suggestion, inspired by McTaggart, that a complete, i.e. indexical-free description of a temporal reality is impossible. And in Section 4, I connect Barb...

  11. La traduction chez Schwob

    Directory of Open Access Journals (Sweden)

    María José Hernández Guerrero

    2007-04-01

    Full Text Available Although Marcel Schwob produced works of great beauty, his facet as a translator is virtually unknown. He is aware that all literary work loses certain qualities in translation and seeks to replace these losses by using his talent as a writer and by applying the method he called the “analogy of languages and literatures at identical stages of formation”. According to this theory languages share similar stages of development and any one language will present analogies with another language of the same period. The translator must therefore revert to the language used when the original text was written. Schwob put this principle into practice with great success in his transla-tions of Shakespeare and Defoe.

  12. Lune chez les Touaregs

    OpenAIRE

    Claudot-Hawad, Hélène

    2007-01-01

    International audience Etude des appellations de la lune en touareg (berbère), des significations, des connotations et de la cosmologie où cet astre apparaît comme la figure par excellence du féminin.

  13. Mourir chez soi

    Science.gov (United States)

    Kiyanda, Brigitte Gagnon; Dechêne, Geneviève; Marchand, Robert

    2015-01-01

    Résumé Objectif Démontrer que des infirmières dédiées en soins palliatifs d’un centre local de services communautaires (CLSC) urbain peuvent garder à domicile jusqu’au décès plus de 50 % de leurs patients en fin de vie et que le suivi médical à domicile est un facteur déterminant du décès à domicile. Type d’étude Analyse du lieu de décès des patients décédés en 2012 et 2013 suivis par les infirmières dédiées (N = 212), en fonction du suivi médical. Contexte Soins palliatifs du CLSC de Verdun, un territoire urbain situé dans le sud-ouest de Montréal. Participants Un total de 212 patients en fin de vie décédés en 2012 et 2013, suivis par 3 infirmières dédiées en soins palliatifs. Principaux paramètres à l’étude Le pourcentage de décès à domicile. Résultats Des 212 patients suivis à domicile par les infirmières en soins palliatifs, 56,6 % sont décédés à domicile, 62,6 % lorsque suivis par des médecins à domicile du CLSC, contre 5,0 % lorsque sans médecin à domicile. Conclusion Le développement des services médicaux à domicile au Québec, couplé à une simple restructuration des services de soins infirmiers des CLSC, permettrait à plus de 50 % des patients en fin de vie à domicile suivis par ces CLSC d’y demeurer jusqu’au décès, le souhait d’une majorité.

  14. La cryptique chez Montaigne

    OpenAIRE

    Knop, Déborah

    2012-01-01

    “A sauts et à gambades”: from this expression in the Essays, critics often came to the conclusion of a rambling speech. Our work shows that this is not the case in many chapters, by referring to the “cryptical method” in the writings of Ramus (Dialectique, 1555) and Canaye (L'Organe, 1589) and to the rhetorical concept of ductus or progression of speech in which the dux-writer circumvents his reader's opposition or hostility, or repugnantia. The first part, which is based on major rhetorical ...

  15. 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

  16. Étude des anomalies chromosomiques après radiothérapie chez des patients traités pour lymphome malin non-Hodgkinien

    Science.gov (United States)

    Mahe, M. A.; André, M. J.; Moyon, E.; Le Mevel, A.; Soubeyran, P.; Hamidou, M.; Milpied, N.; Bourdin, S.; Cuillière, J. C.; Chatal, J. F.

    1998-04-01

    Structural chromosome defects were evaluated in the lymphocytes of 30 patients (pts) who had undergone radiotherapy for non Hodgkin's lymphoma (NHL). Twelve had received 20 Grays (Gy) over the abdomen (group I), 12 whole body irradiation at 1.5 Gy (group II) and 6 whole body irradiation at 15 Gy (group III). A cohort of 468 unirradiated pts served as controls. For the irradiated group, 7% of cells had aberrations compared to 0.4% in controls {P statistically higher in group I (12%) than in group II (3.5%) and III (2.5%) . In group I, frequency of aberrations was statistically higher in pts who had additionnal extra-abdominal involved field irradiation, those with evolutive NHL and those receiving chemotherapy at the time of the cytogenetic analysis. Les aberrations chromosomiques ont ,été, mesurées sur les lymphocytes de 30 patients (pts) irradiés pour lymphome malin non-hodgkinien (LNH) selon 3 modalités : 20 Grays (Gy) sur l'abdomen (groupe I : 12 pts), Irradiation corporelle totale 1,5 Gy (groupe II : 12 pts), ou 15 Gy (groupe III : 6 pts). Une population non irradiée de 468 pts a servi de témoin. Dans le groupe irradié, 7 % des cellules présentaient des anomalies contre 0,4 % dans le groupe témoin {P <10-6}. Les aberrations ,étaient statistiquement plus nombreuses dans le groupe I (12 % des cellules) que dans les groupes II (3,5 %) et III (2,5 %). Dans le groupe I, les anomalies , étaient statistiquement plus fréquentes chez les pts ayant eu une irradiation localisée extra-abdominale en complément de celle de l'abdomen ainsi que chez ceux en rechute de leur LNH et ceux recevant une chimiothérapie lors de l',étude cytogénétique.

  17. 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

  18. 草甘膦对可食用蓝藻葛仙米生长和生理的影响%EFFECTS OF ACUTE GLYPHOSATE EXPOSURE ON THE GROWTH AND PHYSIOLOGY OF NOSTOC SPHAEROIDES, AN EDIBLE CYANOBACTERIUM OF PADDY RICE FIELDS

    Institute of Scientific and Technical Information of China (English)

    阮祚禧; Murray T.Brown

    2008-01-01

    The productivity of Nostoc sphaeroides,an edible cyanobacterium found in paddy rice fields has declined in recent years. It may relate to the increased application of agricultural herbicides. To assess the impact of glyphosate exposure(0.15,0.30,0.45 and 0.6 mmol/L Gly acid) ,the effects on colony size,dry biomass accumulation,chlorophyll a fluorescence (Fv/Fm) and chlorophyll a biosynthesis were investigated over an 8d period. All parameters were significantly inhibited in a concentration used and time dependent way. After 2d exposure to 0. 15 mmol/L Gly colonies were approximately 15% smaller than the controls. After 4d exposure,chlorophyll a content and Fv/Fm were affected by the highest concentration used(0.6 mmol/L Gly). By the 8d, chlorophyll biosynthesis and Fv/Fm were significantly inhibited by concentrations greater than 0.15 and 0.3 mmol/L Gly, respectively. The 8d relative growth rates ( RGRs), calculated for dry biomass, were significantly affected by all glyphosate treatments,there was a 60% reduction at 0.15 mmol/L Gly and negative RGRs at higher concentrations indicate a loss of biomass. Exposure to 0. 6 mmol/L Gly was lethal with loss of colony integrity,bleaching of pigments and no photosynthetic activity by 8d. These results are discussed in terms of the mechanisms of toxicity and the potential implications for the long term sustainability of the N. sphaeroides resource.%葛仙米(N.sphaeroides)的产量和产地面积逐年减少,这可能与当地广泛使用除草剂草甘膦有关.为此,本文测定了不同浓度(0.15、0.30、0.45、0.6mmol/L)的草甘膦处理的葛仙米的颗粒大小、干重、叶绿素荧光、叶绿素浓度.所有测量参数与浓度和时间显著相关:0.15mmol/L处理组的颗粒直径较对照组小15%(2d后);叶绿素a浓度和最大量子产率(Fv/Fm)在最高浓度组(0.6mmol/L)4d后开始受到影响;第8天,相对生长速率(以干重计算,大于0.15mmol/L)、光合作用活性(大于0.3mmol

  19. Extraction and Separation of Carotenoids of Hydrogen-Producing Rhodobacter sp%产氢红杆菌类胡萝卜素含量和组分分析

    Institute of Scientific and Technical Information of China (English)

    张晓蓉; 赵春贵; 杨素萍

    2007-01-01

    类胡萝卜素在调节光合细菌产氢中具有重要作用.采用丙酮-甲醇有机溶剂法和KOH甲醇皂化法对产氢红杆菌(Rhodobacter sp.)R7菌株类胡萝卜素进行了提取纯化,并进一步采用硅胶G薄板层析法对提取的类胡萝卜素进行了分离,并结合光谱法对分离的类胡萝卜素进行了定性和定量分析.结果表明,丙酮-甲醇(7:2,VIV)提取3次可将色素提取完全;最佳提取时间为2h;超声波处理与否对提取率影响不明显;该工艺提取类胡萝卜素产率为2.81mg/g湿菌体.硅胶G薄板层析表明该菌株类胡萝卜素有4个主要组分:黄色、红色、浅红色和浅黄色,黄色和红色为主要成分,光谱学数据显示黄色组分为球形烯,红色组分为螺菌黄质系类胡萝卜素,表明产氢红杆菌类胡萝卜素代谢途径独特.

  20. DNA sequence and genetic analysis of the Rhodobacter capsulatus nifENX gene region: homology between NifX and NifB suggests involvement of NifX in processing of the iron-molybdenum cofactor.

    Science.gov (United States)

    Moreno-Vivian, C; Schmehl, M; Masepohl, B; Arnold, W; Klipp, W

    1989-04-01

    Rhodobacter capsulatus genes homologous to Klebsiella pneumoniae nifE, nifN and nifX were identified by DNA sequence analysis of a 4282 bp fragment of nif region A. Four open reading frames coding for a 51,188 (NifE), a 49,459 (NifN), a 17,459 (NifX) and a 17,472 (ORF4) dalton protein were detected. A typical NifA activated consensus promoter and two imperfect putative NifA binding sites were located in the 377 bp sequence in front of the nifE coding region. Comparison of the deduced amino acid sequences of R. capsulatus NifE and NifN revealed homologies not only to analogous gene products of other organisms but also to the alpha and beta subunits of the nitrogenase iron-molybdenum protein. In addition, the R. capsulatus nifE and nifN proteins shared considerable homology with each other. The map position of nifX downstream of nifEN corresponded in R. capsulatus and K. pneumoniae and the deduced molecular weights of both proteins were nearly identical. Nevertheless, R. capsulatus NifX was more related to the C-terminal end of NifY from K. pneumoniae than to NifX. A small domain of approximately 33 amino acid residues showing the highest degree of homology between NifY and NifX was also present in all nifB proteins analyzed so far. This homology indicated an evolutionary relationship of nifX, nifY and nifB and also suggested that NifX and NifY might play a role in maturation and/or stability of the iron-molybdenum cofactor. The open reading frame (ORF4) downstream of nifX in R. capsulatus is also present in Azotobacter vinelandii but not in K. pneumoniae.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2747620

  1. 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

  2. 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)

  3. Effet d'une complémentation azotée sur la pathologie de la trypanosomose animale africaine chez les moutons sahéliens

    Directory of Open Access Journals (Sweden)

    Kanwé, AB.

    2007-01-01

    Full Text Available Effect of a Complementation Nitrogenized on the Pathology of Animal Trypanosomiasis at the Sahelian Sheeps. La méthode thermique pour la détermination de flux de sève et la chambre à pression pour mesurer les potentiels hydriques foliaire et xylémique, ont été utilisées chez l'olivier de table Olea europaea cv Meski pour estimer la conductance hydraulique et la participation élémentaire des 4 branches selon l'orientation et l'exposition aux radiations solaires. Les mesures ont été effectuées du 23-10-2004 au 30-11-2004 dans un verger d'olivier de table et principalement sur deux arbres de la variété la plus commercialisée Meski. Cette étude a permis l'estimation de la conductance globale de la plante ainsi que la contribution de chaque génératrice. Les taux des conductances hydrauliques partielles sont respectivement de 43, 24, 20 et 13% dans les branches est, nord, sud et ouest. Elle a montré l'importance de l'interception lumineuse dans le déterminisme des flux de sève et des potentiels hydriques foliaires dans chaque branche, et par conséquent la liaison avec le mode de taille et la densité de plantation à préconiser.

  4. Molecular Regulation of Photosynthetic Carbon Dioxide Fixation in Nonsulfur Purple Bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Tabita, Fred Robert [The Ohio State Univ., Columbus, OH (United States)

    2015-12-01

    The overall objective of this project is to determine the mechanism by which a transcriptional activator protein affects CO2 fixation (cbb) gene expression in nonsulfur purple photosynthetic bacteria, with special emphasis to Rhodobacter sphaeroides and with comparison to Rhodopseudomonas palustris. These studies culminated in several publications which indicated that additional regulators interact with the master regulator CbbR in both R. sphaeroides and R. palustris. In addition, the interactive control of the carbon and nitrogen assimilatory pathways was studied and unique regulatory signals were discovered.

  5. Antagonistic Activities of Purple Non-sulfur Bacterial Extracts Against Antibiotic Resistant Vibrio sp.

    Directory of Open Access Journals (Sweden)

    Chandrasekaran, R.

    2011-01-01

    Full Text Available Solvent extracts of native purple non-sulfur bacterial (PNSB isolates from the effluents of brackish shrimp culture ponds, near Nagapattinam coast (South India were evaluated for antibacterial activity by the disc diffusion method. Best results were shown by the chloroform extracts against oxytetracycline resistant Vibrio harveyi and Vibrio fischerii. Among the purple non-sulfur bacterial isolates, Rhodobacter sphaeroides, showed maximum antagonistic activity. The findings suggest that the antagonistic extracts from Rba. sphaeroides could be used as an effective antibiotic in controlling Vibrio spp., in aquaculture systems.

  6. Gibbosité vertébrale congénitale évoquant un mal de Pott chez un nouveau-né de mère tuberculeuse: à propos d'un cas et revue de la literature

    Science.gov (United States)

    Katamea, Tina; Mukuku, Olivier; Luboya, Oscar Numbi

    2014-01-01

    Les formes latentes de tuberculose chez la femme enceinte sont associées à un risque élevé de passage à une forme active qui augmente le risque de transmission de la mère infectée à l'enfant dans les 3 premières semaines de vie. Nous rapportons un cas de Gibbosité vertébrale congénitale évoquant un mal de Pott chez un nourrisson de mère tuberculeuse, observé à Lubumbashi, en République Démocratique du Congo. PMID:25478046

  7. 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)

  8. Impact d'une supplémentation en spiruline chez des enfants malnutris sévères dans le cadre de la réhabilitation nutritionnelle. Essai clinique randomisé en double aveugle

    OpenAIRE

    Doudou Halidou, Maïmouna

    2008-01-01

    Introduction Près de 842 millions de personnes dans le monde sont toujours sous- alimentées ou exposées à une insécurité alimentaire chronique. Or une consommation insuffisante en protéines et en calories, ainsi que les carences en micronutriments ont un impact majeur sur la morbidité et la mortalité, en particulier chez les enfants. On estime qu’entre 2000 et 2005 le nombre d’enfants présentant une insuffisance pondérale a augmenté dans la plupart des régions d’Afrique sub saharienne, alo...

  9. Impact d'une supplémentation en spiruline chez les enfants malnutris sévères dans le cadre de la réhabilitation nutritionnelle: esai clinique randomisé en double aveugle

    OpenAIRE

    Doudou Halidou, Maïmouna

    2008-01-01

    IntroductionPrès de 842 millions de personnes dans le monde sont toujours sous- alimentées ou exposées à une insécurité alimentaire chronique. Or une consommation insuffisante en protéines et en calories, ainsi que les carences en micronutriments ont un impact majeur sur la morbidité et la mortalité, en particulier chez les enfants. On estime qu’entre 2000 et 2005 le nombre d’enfants présentant une insuffisance pondérale a augmenté dans la plupart des régions d’Afrique sub saharienne, alors q...

  10. Troubles du sommeil, symptômes anxio-dépressifs et risque cardio-vasculaire chez les hypertendus noirs africains: étude transversale de 414 hypertendus suivis en ambulatoire au CHU de Ouagadougou (Burkina Faso)

    OpenAIRE

    Yaméogo, Nobila Valentin; Samadoulougou, André; Kagambèga, Larissa Justine; Yaméogo, Aimé Arsène; Ilboudo, Eric; Millogo, Georges; Kologo, Jonas; Toguyeni, Jean Yves; Simporé, Jacques; Zabsonré, Patrice

    2015-01-01

    Introduction Dans le but de déterminer la fréquence des troubles du sommeil, de l'anxiété et de la dépression, et de rechercher l'existence d'une relation entre ces troubles et le risque cardio-vasculaire global chez les hypertendus noirs africains, nous avons réalisé une étude transversale de mai 2010 à mars 2011 à l'unité de consultation externe du service de cardiologie du CHU-Yalgado Ouédraogo de Ouagadougou qui a inclut 414 hypertendus adultes suivis en ambulatoire. Après un examen clini...

  11. ÇEva(uation Les marqueurs de raperoxyéation Iipidique Chez (es rates « WISTJ4çR» soumises au régime hiyperg ras

    OpenAIRE

    ABOURA, IKRAM

    2014-01-01

    L'obésité est un problème majeur de santé publique, elle est devenue la pathologie nutritionnelle la plus fréquente aussi bien dans les pays industrialisés que dans le reste du monde. L'obésité constitue un facteur de risque pour le développement de plusieurs maladies chroniques à cause des modifications des paramètres métaboliques notamment les marqueurs du stress oxydatif. L'objectif de notre travail est de déterminer quelques paramètres de stress oxydatif chez les rates d...

  12. Recherches sur le psychodiagnostic de Rorschach chez 110 enfants impubères (6 à 15 ans atteints de troubles névrotiques divers

    Directory of Open Access Journals (Sweden)

    M. Schachter

    1951-03-01

    Full Text Available Nous nous sommes propôs's d'étudier à la lumière du Rorschach, 110 enfants impubères atteints de troubles névrotiques divers. II s'agit de su-jets énurétiques (70 cas, de masturbateurs, instables, psycho-moleurs, colé-reux, mythomanes, fugueurs ou voleurs, onychophages ; en somme, ce soni "des petits caractériels". Ajoutons, toutefois, que nous avons éliniiné soigneu-sement les débiles mentaux proprement dits. Nous avons calcule les divers facteurs du test, aussi bien les moyennes arithmétiques que les médianes et les dispersions porcentuelles, toutes les fois que les matériaux étaient. suffisamment importantes. Nous donnons, ici, seulement les valeurs médianes, les plus utiles pour la recherche psychologique-statistique: a nombre des réponses, 22; b nombre des interpretations globales (G, 3,5; c nombre des interpretations de detail (D, 14,7; d nombre des interpretations de petits details (Dd, 2,5; e nombre des interpretations de details intermaculaires (DB1, 0,5; f nombre des details inhibitifs (Do, 0; g les "types de perceptions" (Erfassungtypus les plus couramment notes sont G-D-Dd (33,63% et G-D-Dd-Db1 (26,36%; le G pur est absent; le G-D-Dd est le plus rarement note (1,81% ; h la mediane des +F% est de 66, soit une valeur normale ou, du moins, supraliminale; i nombre des interpretations kines-thésiques (K, 0,5; j nombre des interpretations couleur-pure (C, 0; k nombre des interpretations couleur-forme (CF, 0,7; 1 nombre des interpretations forme-couleur (FC, 2,1; m la formule de reaction (Erlebnistypus ou experience balance la plus significative (en valeurs médianes est du type 0,5/2,8, montrant pratiquement une extra-tensivité nette. En fait, cette formule nous l'avons notée chez 66,36% de nos 110 enfants. La formule la plus rare est celle de l'ambiéqualité (4,54%; n le nombre des interpretations Clob n'a été calculé, car le materiel est faible. Ces réponses sont données par seulement 6 enfants (5,44% des su

  13. Incidence des accidents vasculaires cérébraux chez les patients VIH positifs sous traitement antirétroviral au long court

    Science.gov (United States)

    Mapoure, Yacouba Njankouo; Nkongni, Ines Nepetsoun; Luma, Henry Namme; Ngahane, Bertrand Hugo Mbtachou; Barla, Esther; Ngwane, Samuel; Mouelle, Albert Soné; Njamnshi, Alfred Kongnyu

    2016-01-01

    Introduction Avec l'introduction de la trithérapie dans les années 1996, la morbidité et la mortalité liées à l'infection par le VIH a nettement diminué. Concomitamment avec ce succès clinique, plusieurs changements métaboliques incluant diabète, hypertension artérielle, dyslipidémie et lipodystrophie ont été observés, ceux-ci étant des pourvoyeurs d'accidents vasculaires cérébraux. L'objectif de ce travail était de déterminer l'incidence des accidents vasculaires cérébraux chez les patients VIH positifs sous traitement antirétroviral au long court. Méthodes Il s'agissait d'une étude de cohorte rétrospective, menée dans le Centre de Traitement Agrée de l'Hôpital Général de Douala (HGD), avec un recueil des données sur 10 ans allant de Mai 2001 à avril 2010, portant sur les patients VIH positifs adultes sous traitement antirétroviral depuis au moins 6 mois. Les patients étaient suivis selon le protocole national de prise en charge du Cameroun. La survenue d'un AVC a été déterminée par la méthode Kaplan-Meyer tandis que les facteurs associés à la survenue d'un AVC ont été recherché par le test de Khi-2. Le seuil de signification statistique était fixé à 0,05. Résultats 307 patients étaient inclus dont 62,4% de sexe féminin, et l’âge moyen était de 40,1 ± 9,9 ans. L'incidence des AVC était de 1,7% sur 72 mois de suivi sans différence significative entre les femmes et les hommes (P= 0,76). Le taux d'incidence calculé était de 0,3 pour 100 personnes années. Dans 85,7% des cas il s'agissait d'un AVC ischémique. Le délai moyen de survenue d'un AVC était de 33,4 mois. Les facteurs associés à la survenue d'un AVC étaient: les patients ayant initié leur traitement au stade III et IV de l'OMS et le taux de CD4 > 100/mm3 à l'initiation du traitement antirétroviral. Conclusion L'incidence des AVC chez les patients VIH positifs sous traitement antirétroviral est similaire à celle rapportée ant

  14. Rôle de la morphologie chez les enfants dyslexiques : étude des effets d'un entraînement morphologique

    Directory of Open Access Journals (Sweden)

    Bogliotti Caroline

    2012-07-01

    Full Text Available Depuis les années 70, la majorité des travaux conduits sur l’apprentissage de la lecture dans un système alphabétique tel que celui utilisé par le français, ont mis en évidence la contribution majeure des habiletés phonologiques à cet apprentissage. La recherche a montré également que les dyslexiques (DL manifestent des difficultés importantes à identifier et traiter les unités non signifiantes (les graphèmes renvoyant aux sons du langage (les phonèmes. En revanche, le traitement des unités de sens tels que mots et morphèmes semble préservé. Des chercheurs ont alors émis l’hypothèse selon laquelle, les DL auraient mis en place une stratégie de lecture compensatoire qui utiliserait une unité formelle codant non pas le son mais le sens dénommé morphème (la plus petite unité de sens véhiculée par la langue. Ainsi, le développement de la conscience morphologique, c’est à dire la conscience de la structure morphémique des mots, et la capacité à manipuler cette structure, seraient préservées chez les enfants DL. Le repérage des unités morphémiques constituerait donc une aide non négligeable pour ces enfants. Dans notre recherche, nous avons étudié les effets d’un entraînement morphologique oral et écrit chez des enfants dyslexiques âgés de 10 à 14 ans, suivis individuellement pendant 20 semaines. Nous avons comparé le décodage de ces enfants à celui d’un groupe contrôle d’enfants dyslexiques, apparié en âge chronologique et en âge lexique mais n’ayant pas bénéficié de l’entraînement. Certaines catégories de mots sont apparues plus sensibles à l’entraînement (ex : diminution de 62 % des temps de latence pour les mots pseudo-préfixés. Les enfants suivis, qui avaient un retard de lecture important (en moyenne 35 mois, ont pu bénéficier de l’entraînement. Une amélioration significative du décodage (gain de 9 mois en âge lexique, et des progrès en conscience

  15. Spectral Trends in the Fluorescence of Single Bacterial Light-Harvesting Complexes: Experiments and Modified Redfield Simulations

    Science.gov (United States)

    Rutkauskas, Danielis; Novoderezhkin, Vladimir; Gall, Andrew; Olsen, John; Cogdell, Richard J.; Hunter, C. Neil; van Grondelle, Rienk

    2006-01-01

    In this work we present and discuss the single-molecule fluorescence spectra of a variety of species of light-harvesting complexes: LH2 of Rhodopseudomonas acidophila, Rhodobacter sphaeroides, and Rhodospirillum molischianum and LH1 of Rhodobacter sphaeroides. The emission spectrum of these complexes varies as a function of time as was described in earlier work. For each type of complex, we observe a pronounced and well-reproducible characteristic relationship between the fluorescence spectral parameters of the peak wavelength, width, and asymmetry. This dependence for the LH2 complexes can be quantitatively explained on the basis of a disordered exciton model by varying the static disorder and phonon coupling parameters. In addition, a correlation of the pigment site energies has to be assumed to interpret the behavior of the LH1 complex. PMID:16399834

  16. Diagnostic moléculaire du Cytomégalovirus (CMV), de l’herpès virus humain de type 6 (HHV6) et d’Epstein-Barr virus (EBV) par PCR en temps réel chez les femmes enceintes VIH séropositives et séronégatives à Ouagadougou, Burkina Faso

    Science.gov (United States)

    Ouedraogo, Alice Rogomenoma; Kabre, Madeleine; Bisseye, Cyrille; Zohoncon, Théodora Mahoukèdè; Asshi, Maleki; Soubeiga, Serge Théophile; Diarra, Birama; Traore, Lassina; Djigma, Florencia Wendkuuni; Ouermi, Djénéba; Pietra, Virginio; Barro, Nicolas; Simpore, Jacques

    2016-01-01

    Introduction Les herpès virus EBV, CMV et HHV-6 sont des virus qui évoluent sous le modèle pandémique et sont responsables d’infections congénitales pouvant provoquer des séquelles graves chez les nouveau-nés. L’objectif de cette étude était de déterminer les prévalences de CMV, EBV et HHV-6 chez les femmes enceintes VIH(+) et VIH(-) à Ouagadougou. Méthodes Dans cette étude 200 échantillons de plasma sanguin de femmes enceintes dont 100 femmes VIH(+) et 100 femmes VIH(-) ont été diagnostiqués par PCR multiplex en temps réel pour les trois infections (EBV, CMV et HHV-6). Résultats Sur l’ensemble des 200 échantillons analysés, 18 (9,0%) étaient positifs à au moins un des trois virus, 12 (6,0%) étaient positifs au EBV, 13 (6,5%) au CMV et 12 (6,0%) positifs au HHV-6. Parmi les 18 cas d’infections, nous avons trouvé 10 cas (55,6%) de coïnfections dont 90,0% (9/10) d’infection multiple EBV/CMV/HHV6 et 10,0% de coinfection EBV/HHV6. Le taux d’infection HHVs était plus élevé chez les femmes VIH(-) que celles VIH(+) (12,0% versus 6,0%). Parmi les VIH(+), la PCR a révélé 7,1% (soit 6/85) d’infection HHVs chez celles qui n’étaient pas sous ARV contre 0% chez celles sous ARV. Conclusion Les herpès virus sont fréquents chez les femmes enceintes au Burkina Faso et pourraient constituer une menace chez ces dernières à cause des complications et des risques d’infection pour le nouveau-né. PMID:27800078

  17. 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

  18. L'acétylcholinestérase des poissons, cible des organophosphorés et des carbamates. Caractérisation du gène et des formes moléculaires de l'enzyme chez Danio rerio. Effets des anticholinestérasiques

    Directory of Open Access Journals (Sweden)

    BERTRAND C.

    1998-07-01

    Full Text Available L'acétylcholinestérase (AChE, EC 3.1.1.7 est une enzyme indispensable de la transmission synaptique cholinergique. Son inhibition par les organophosphorés et les carbamates est à la base de certains traitements insecticides et nématicides utilisés en agriculture. Les faunes sauvage (en particulier les poissons et domestique sont exposées aux résidus des traitements anticholinestérasiques. La mesure de l'inhibition de l'activité AChE chez ces espèces est un marqueur fiable de l'exposition. Ceci est montré ici pour l'AChE de carpes exposées expérimentalement au carbofuran (carbamate. Nous présentons parallèlement des données sur le gène de l'AChE chez Danio rerio et sur les formes moléculaires de l'enzyme chez Danio, Cyprinus carpio et Oncorhynchus mykiss. Contrairement à ce qui est observé chez d'autres vertébrés, le gène d'AChE de Danio ne possède pas d'exon H et seules les sous-unités de type T ont pu être identifiées chez ces trois espèces. Des résultats préliminaires d'hybridation in situ sur les embryons sont présentés et nous discutons l'intérêt des expériences de transgenèse dans l'oeuf de Danio pour étudier d'éventuelles fonctions morphogénétiques de l'AChE au début du développement.

  19. Antagonistic Activities of Purple Non-sulfur Bacterial Extracts Against Antibiotic Resistant Vibrio sp.

    OpenAIRE

    Chandrasekaran, R.; Ashok Kumar, G. V.

    2011-01-01

    Solvent extracts of native purple non-sulfur bacterial (PNSB) isolates from the effluents of brackish shrimp culture ponds, near Nagapattinam coast (South India) were evaluated for antibacterial activity by the disc diffusion method. Best results were shown by the chloroform extracts against oxytetracycline resistant Vibrio harveyi and Vibrio fischerii. Among the purple non-sulfur bacterial isolates, Rhodobacter sphaeroides, showed maximum antagonistic activity. The findings suggest that the...

  20. GenBank blastx search result: AK243680 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK243680 J100090I20 AF018073.1 AF018073 Rhodobacter sphaeroides operon regulator (smoC), periplasmic sorbito...l-binding protein (smoE), sorbitol/mannitol transport inner membrane protein (smoF), sorbitol.../mannitol transport inner membrane protein (smoG), sorbitol/mannitol transport ATP-binding transport protein (smoK), sorbit...ol dehydrogenase (smoS), mannitol dehydrogenase (mtlK),

  1. GenBank blastx search result: AK240874 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK240874 J065025K09 AF018073.1 AF018073 Rhodobacter sphaeroides operon regulator (smoC), periplasmic sorbito...l-binding protein (smoE), sorbitol/mannitol transport inner membrane protein (smoF), sorbitol.../mannitol transport inner membrane protein (smoG), sorbitol/mannitol transport ATP-binding transport protein (smoK), sorbit...ol dehydrogenase (smoS), mannitol dehydrogenase (mtlK),

  2. GenBank blastx search result: AK241729 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK241729 J065199L10 AF018073.1 AF018073 Rhodobacter sphaeroides operon regulator (smoC), periplasmic sorbito...l-binding protein (smoE), sorbitol/mannitol transport inner membrane protein (smoF), sorbitol.../mannitol transport inner membrane protein (smoG), sorbitol/mannitol transport ATP-binding transport protein (smoK), sorbit...ol dehydrogenase (smoS), mannitol dehydrogenase (mtlK),

  3. Global Analysis of Photosynthesis Transcriptional Regulatory Networks

    OpenAIRE

    Imam, Saheed; Noguera, Daniel R.; Donohue, Timothy J.

    2014-01-01

    Photosynthesis is a crucial biological process that depends on the interplay of many components. This work analyzed the gene targets for 4 transcription factors: FnrL, PrrA, CrpK and MppG (RSP_2888), which are known or predicted to control photosynthesis in Rhodobacter sphaeroides. Chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) identified 52 operons under direct control of FnrL, illustrating its regulatory role in photosynthesis, iron homeostasis, nitrogen met...

  4. Global analysis of photosynthesis transcriptional regulatory networks.

    OpenAIRE

    Saheed Imam; Noguera, Daniel R.; Donohue, Timothy J.

    2014-01-01

    Photosynthesis is a crucial biological process that depends on the interplay of many components. This work analyzed the gene targets for 4 transcription factors: FnrL, PrrA, CrpK and MppG (RSP_2888), which are known or predicted to control photosynthesis in Rhodobacter sphaeroides. Chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) identified 52 operons under direct control of FnrL, illustrating its regulatory role in photosynthesis, iron homeostasis, nitrogen met...

  5. Mapping lipid and detergent molecules at the surface of membrane proteins.

    Science.gov (United States)

    Cogdell, Richard J; Gardiner, Alastair T; Roszak, Aleksander W; Stončius, Sigitas; Kočovský, Pavel; Isaacs, Neil W

    2011-06-01

    Electron-density maps for the crystal structures of membrane proteins often show features suggesting binding of lipids and/or detergent molecules on the hydrophobic surface, but usually it is difficult to identify the bound molecules. In our studies, heavy-atom-labelled phospholipids and detergents have been used to unequivocally identify these binding sites at the surfaces of test membrane proteins, the reaction centres from Rhodobacter sphaeroides and Blastochloris viridis. The generality of this method is discussed in the present article.

  6. GenBank blastx search result: AK289073 [KOME

    Lifescience Database Archive (English)

    Full Text Available AK289073 J090094I16 AF016236.1 AF016236 Rhodobacter sphaeroides DMSO/TMAO-sensor kinase (dorS), DMSO.../TMAO-response regulator (dorR), DMSO/TMAO-cytochrome c-containing subunit (dorC), DMSO-mem...brane protein (dorB), and DMSO/TMAO-reductase (dorA) genes, complete cds. BCT 0.0 0 ...

  7. Hydrophobic organization of membrane proteins

    OpenAIRE

    Rees, D C; DeAntonio, L.; Eisenberg, D.

    1989-01-01

    Membrane-exposed residues are more hydrophobic than buried interior residues in the transmembrane regions of the photosynthetic reaction center from Rhodobacter sphaeroides. This hydrophobic organization is opposite to that of water-soluble proteins. The relative polarities of interior and surface residues of membrane and water soluble proteins are not simply reversed, however. The hydrophobicities of interior residues of both membrane and water-soluble proteins are comparable, whereas the bi...

  8. Epilepsies et crises épileptiques aiguës chez l'enfant en Afrique subsaharienne: défis et espoirs

    Science.gov (United States)

    Kaputu-Kalala-Malu, Célestin

    2016-01-01

    L’épilepsie est une maladie neurologique fréquemment rencontrée en Afrique Subsaharienne (ASS) au sein de la population pédiatrique. Bien que sa prévalence exacte au sein de cette population ne serait pas connue, il y a lieu de penser qu'elle n'est pas très différente de celle de la population générale à cause de l’âge précoce de son début - avant 20 ans dans plus 60% des cas - et à l'absence de la distribution bimodale retrouvée dans les pays industrialisés. Tout au long de cette revue de la littérature, une réalité se dégage: la prise en charge globale de l'enfant épileptique en ASS est inadéquate. Pour inverser cette tendance, les défis à relever semblent être de trois ordres. Outre la recherche, ces défis comportent une dimension thérapeutique et une dimension éducationnelle. Il y a nécessité de former des médecins à la pratique de la neurologie pédiatrique tout en créant des conditions de travail qui limitent la fuite des cerveaux. Il est urgent d'identifier et de combler les besoins nécessaires à la prise en charge correcte des enfants épileptiques selon les pays et les régions (indisponibilité des médicaments anti comitiaux, l'absence des guidelines nationaux, le déficit d'encadrement de guérisseurs traditionnels…) enfin, il est impérieux d'encourager la réalisation des études visant à établir l'incidence et la prévalence correctes des épilepsies chez l'enfant afin de faciliter la pose des jalons des mesures de lutte ciblées. PMID:27217883

  9. Ending homelessness among people with mental illness: the At Home/Chez Soi randomized trial of a Housing First intervention in Toronto

    Science.gov (United States)

    2012-01-01

    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%), alcohol

  10. 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.

  11. 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

  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

    OpenAIRE

    Kovesi, Tom; Giles, Brenda Louise; Pasterkamp, Hans

    2012-01-01

    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 bronchodilatat...

  13. 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 < 0,001) chez les enfants dont les mères étaient sous combinaison AZT/3TC/NVP ou sous prophylaxie AZT/3TC et de 15,0% (6/40) chez les enfants orphelins qui n’étaient pas inclus dans le protocole de la PTME. Conclusion Selon les résultats, le protocole de la PTME est efficace et réduit très significativement le risque de transmission du 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

  14. Clonage, caractérisation et étude de la régulation transcriptionnelle du gène Aox1 encodant l'oxydase alternative chez Chlamydomonas reinhardtii

    OpenAIRE

    Baurain, Denis

    2003-01-01

    Au sein de la membrane interne des mitochondries, quatre complexes multiprotéiques sont impliqués dans le transfert des électrons depuis les équivalents réducteurs jusqu'à l'oxygène moléculaire. L'énergie associée à ce transport au travers des complexes I, III et IV est couplée à la synthèse d'ATP par l'intermédiaire d'un gradient de protons. Chez les plantes supérieures, de nombreux champignons et quelques protistes, une seconde voie de transfert diverge de la voie principale au niveau du po...

  15. Contrôle de l'homéostasie redox et détection des oxydants. Régulation du facteur de transcription Yap1 chez S. cerevisiae

    OpenAIRE

    Delaunay, Agnès

    2002-01-01

    Le maintien d'une homéostasie redox intracellulaire est essentielle à la survie de la cellule. Pour cela, la cellule doit réguler la concentration intracellulaire en intermédiaires réactifs de l'oxygène (ou IRO), sous-produits de la respiration. La connaissance que nous avons des mécanismes de contrôle de l'homéostasie redox repose principalement sur des données obtenues chez la bactérie. Nous avons donc choisi un eucaryote comme modèle d'étude, la levure S. cerevisiae. Le facteur de transcri...

  16. Etude des flux de carbone et d'azote chez des blés hybrides et leurs parents, pendant la période de remplissage des grains

    OpenAIRE

    Oury, F.X.; Triboï, E; Bérard, P; Ollier, J L; Rousset, M

    1995-01-01

    Les flux de carbone et d’azote ont été étudiés entre floraison et maturité, chez 29 hybrides de blé et leurs 23 parents. Ce matériel végétal provenait d’une expérimentation en blocs complets randomisés, la parcelle élémentaire étant de 7 m2. L’hybride manifeste un hétérosis pour le rendement en grains, mais également pour le rendement en azote : à vitesse de remplissage par m2 pour l’azote équivalente, la F1 a une durée de remplissage pour l’azote supérieure à celle de la lignée. Pour les F1 ...

  17. Sarcopénie et médication : données expérimentales obtenues chez le rat soumis à un traitement chronique au paracétamol

    OpenAIRE

    Mast, Carole; Savary-Auzeloux, Isabelle; Remond, Didier; Pouyet, Corinne; Centeno, Delphine; Voyard, G.; Combaret, Lydie; Dardevet, Dominique; PAPET, Isabelle

    2015-01-01

    La sarcopénie peut résulter, entre autres, d’un défaut de disponibilité en un seul acide aminé au niveau musculaire. La fourniture de cystéine au muscle pourrait être réduite par la prise chronique de paracétamol. En effet, cet acide aminé est consommé par le foie pour produire le sulfate et le glutathion, qui sont nécessaires à la détoxication de ce médicament. L’effet pro-sarcopéniant potentiel du paracétamol a été testé chez le rat âgé. Quatorze rats Wistar mâles âgés de 22 mois ont reç...

  18. Effet d'un régime enrichi en chlorpyrifos chez le rat Wistar: étude de l'activité enzymatique des cholinestérases comme indicateur biologique

    OpenAIRE

    Benziane, Ahmed Djihad

    2015-01-01

    Les intoxications aigiies par les pesticides organophosphorés (OP) sont responsables d'une lourde mortalité mondiale, en particulier dans les pays en voie de développement à fort potentiel agricole. Ces produits OP sont responsables d'intoxications de gravité variable selon la nature du composé et des quantités ingérées. Le présent travail porte - sur l'étude de l'effet de la toxicité sur l'activité cholinestérasique et quelques paramètres de la fonction hépatique chez les rats...

  19. L'étranger de la théorie chez P. Fédida: la théorie de la supervision et le Centre d'Estudes du Vivant

    Directory of Open Access Journals (Sweden)

    François Villa

    2007-09-01

    Full Text Available L'auteur montre qu 'il y a, chez P. Fédida, une continuité de démarche entre sa théorie de la psychanalyse de supervision et la théorie sur laquelle repose le projet du Centre d'Etudes du Vivant. Tant dans la supervision que dans la controverse entre la psychanalyse et d'autres disciplines, ce qui est en jeu c'est l'étranger de la théorie. Celui-ci défait l'illusion des supposées bases communes de la psychanalyse. C'est à partir de cet interlocuteur " interne" à chaque discipline que peut s'organiser une controverse sur les objets qui sont à la frontière des diverses sciences du vivant.

  20. Les recommandations de prise en charge des complications métaboliques associées aux antipsychotiques de deuxième génération chez les enfants et les adolescents

    Science.gov (United States)

    Ho, Josephine; Panagiotopoulos, Constadina; McCrindle, Brian; Grisaru, Silviu; Pringsheim, Tamara

    2012-01-01

    HISTORIQUE : Les antipsychotiques de deuxième génération s’associent souvent à des complications métaboliques. Ces médicaments sont utilisés plus souvent pour le traitement des troubles de santé mentale chez les enfants, ce qui a requis l’élaboration de lignes directrices officielles sur la surveillance de leur innocuité et de leur efficacité. Des lignes directrices ont déjà été élaborées pour surveiller les complications métaboliques et neurologiques. Afin d’aider les praticiens qui effectuent ces interventions de surveillance, une série de recommandations thérapeutiques complémentaires a été élaborée pour les cas où l’on observe des mesures ou des résultats anormaux. OBJECTIF : Créer des recommandations probantes afin de contribuer à la prise en charge des complications métaboliques chez les enfants traités au moyen d’antipsychotiques de deuxième génération. MÉTHODOLOGIE : Les auteurs ont procédé à une analyse systématique des publications sur les complications métaboliques des antipsychotiques de deuxième génération chez les enfants. Les membres du groupe consensuel ont évalué l’information recueillie grâce à l’analyse bibliographique systématique et ont fait appel à un processus de groupe nominal pour parvenir à un consensus à l’égard de recommandations thérapeutiques. Dans la mesure du possible, ils se sont reportés aux lignes directrices existantes sur l’évaluation et le traitement des anomalies métaboliques chez les enfants. RÉSULTATS : Des recommandations probantes sont présentées pour contribuer à la prise en charge des complications métaboliques, y compris la prise de poids, l’augmentation du tour de taille, l’élévation des taux de prolactine, de cholestérol, de triglycérides et de glucose, les épreuves de fonction hépatique anormales et les études thyroïdiennes anormales. CONCLUSION : Il faut recourir à des mesures de surveillance convenables lorsqu’on prescrit

  1. « Les fonctions du chien chez les pasteurs nomades des montagnes de l’Asie du Sud-Ouest ». Ethnozootechnie, n° 78, 2006, pp. 125-129.

    OpenAIRE

    Bromberger, Christian

    2008-01-01

    Se fondant sur sa longue expérience de terrain chez les Baḫtiyārī et sur une ample bibliographie, l’A. analyse les fonctions manifestes et latentes des chiens de campement et des chiens de troupeau dans les populations de pasteurs nomades qui, de l’Anatolie à l’Himalaya, pratiquent un nomadisme vertical. Chaque famille nucléaire, abritée sous une tente, possède deux ou trois chiens, chargés de protéger les personnes et les biens (les vols de bétail sont fréquents) et qui délimitent, en urinan...

  2. 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...

  3. Est-ce que le massage contribue, en soins palliatifs, à diminuer la douleur, l'anxiété et la dépression chez les personnes atteintes d'un cancer en phase terminale ?: Travail de Bachelor

    OpenAIRE

    Brea, Justine; Randin, Camille; Borel, Catherine

    2013-01-01

    Contexte : Le vieillissement démographique et l’augmentation des maladies chroniques induisent un développement des soins palliatifs et des thérapies complémentaires. Les recherches suggèrent que le massage peut être utilisé afin de soulager les symptômes des personnes atteintes d’un cancer en phase terminale tels que la douleur, l’anxiété et la dépression. Objectif : Identifier l’effet du massage sur la diminution de la douleur, l’anxiété et la dépression chez les personnes atteintes d’un ca...

  4. 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.

  5. Effet des composés phénoliques de la caroube sur les paramètres du stress oxydatif chez des rates soumises à un rypergras

    OpenAIRE

    ARAB, NAZIHA

    2014-01-01

    plante utilisée en médecine traditionnelle mais aussi dans l’alimentation humaine et animale . Les rates femelles de souche «Wistar » ont été soumises à un régime hypèrgras à base de caroube et un régime témoin à base de caroube pendant une durée de 2 mois. Ces régimes on eu comme impact une diminution de la glycémie et du poids corporel chez les rates consommant un régime hypèrgras avec caroube par rapport à celles recevant un régime témoin avec caroube. Le pouvoir antioxydant des comp...

  6. 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.

  7. 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

  8. Présentations inhabituelles d'un syndrome de Plummer-Vinson chez l'africain de race noire: à propos de deux observations

    Science.gov (United States)

    Berthé, Adama; Diop, Madoky Magatte; Toure, Papa Souleymane; Tall, Cheikh Tidiane; Fulgence Faye, Abdoul; Diop, Bernard Marcel; Ka, Mamadou Mourtalla

    2014-01-01

    Le syndrome de Plummer Vinson (SPV) est une affection rare caractérisée par une dysphagie cervicale associée à une anémie ferriprive et un anneau sur l’œsophage supérieur. Parfois, son mode de présentation inhabituelle peut faire errer le diagnostic. Le rétrécissement annulaire peut être de découverte fortuite lors d'une endoscopie digestive haute. Nous rapportons deux observations de syndrome de Plummer-Vinson chez des sujets de genre masculin et féminin. Celles-ci ont comme point commun une découverte fortuite lors d'une endoscopie digestive haute. La première observation concernait un garçon de 14 ans aux antécédents de brûlure caustique de l’œsophage dans l'enfance avec dysphagie haute passagère ne l'inquiétant pas depuis lors. Il était reçu en urgence pour une endoscopie digestive haute motivée par une dysphagie de survenue brutale secondaire à une prise d'aliment solide. L'examen clinique avait objectivé une chéilite angulaire. La biologie montrait un abaissement de la ferritinémie sans anémie. L'endoscopie avait mis en évidence un anneau circulaire franchi avec ressaut au niveau de la bouche de Killian. Elle avait également permis l'extraction d'un corps étranger à type de noyau de « pain de singe » mais la lumière de l’œsophage était infranchissable à partir du niveau d'arrêt. Le transit œsophagien montrait un ralentissement du produit de contraste au niveau de l'sophage cervical et thoracique sans lésions morphologiques. Dans la deuxième observation, il s'agissait d'une jeune femme de 35 ans adressée à l unité d'endoscopie digestive pour objectiver une gastrite atrophique sur une suspicion de la maladie de Biermer. La fibroscopie mettait alors en évidence, un rétrécissement annulaire infranchissable à 18 centimètres des arcades dentaires. La biologie montrait une anémie avec augmentation de la ferritinémie. Dans les deux cas, le traitement martial était systématique associé à des séances de

  9. 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

  10. Le poison chez les Trastamare

    OpenAIRE

    Ramires, Flora

    2012-01-01

    During the last centuries of the Middle Ages, poison seems to have played an important role in Castilian political life, and many authors of chronicles and medical treatises pay attention to the reality of this phenomenon. The article focuses on the use of poison by the Trastamaras, and on its political consequences. We attempt to show the impact of poison on the imagination of contemporaries and on the reality of this practice by members of the Trastamara dynasty, and to demonstrate that ref...

  11. Polyphonie musicale chez Milan Kundera

    DEFF Research Database (Denmark)

    Boisen, Jørn

    Artiklen undersøger, hvordan Milan Kundera i sine romaner anvender kompositionstekniske greb fra musikken, i særdeleshed polyfoni.......Artiklen undersøger, hvordan Milan Kundera i sine romaner anvender kompositionstekniske greb fra musikken, i særdeleshed polyfoni....

  12. 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 lot...

  13. Facteurs prédictifs de la réponse à la CERA chez les hémodialysés chroniques naïfs de traitement par agent stimulant l’érythropoïèse

    Science.gov (United States)

    Ezziani, Mariam; Najdi, Adil; Mikou, Souad; Hanin, Hakim; Arrayhani, Mohammed; Houssaini, Tarik Sqalli

    2015-01-01

    La correction et la stabilité du taux d'hémoglobine est un objectif majeur du traitement de l'anémie chez les hémodialysés chroniques. Toutefois, la cible d'hémoglobine > 11g/dl fixée par les recommandations demeure difficile à atteindre dans notre contexte. Le but de cette étude est d’évaluer la réponse au traitement par CERA (continuous erythropoietin receptor activator) chez une population d'hémodialysés chroniques naïfs de tout traitement par agent stimulant de l’érythropoïèse et étudier les différents facteurs associés à une mauvaise réponse au traitement. Il s'agit une étude prospective mono centrique faite au sein d'une population d’ hémodialysés chroniques. Ont été inclus les patients en hémodialyse depuis plus de 12 mois, naïfs de tout traitement par agent stimulant de l’érythropoïèse (ASE) et ayant un taux d'hémoglobine(Hb) 11g/dl. Sur 87 patients en hémodialyse périodique, 22 (25,3%) sont naïfs de tout traitement par ASE. Il s'agit de 13 hommes et 9 femmes avec un âge moyen de 46 ± 19 ans et une ancienneté en hémodialyse de 67 ± 59 mois. Le taux initial d'hémoglobine est de 7,8 ± 1,3 g/dl. Au bout de 4 mois de traitement régulier par la CERA, le taux final d'Hb est de 10,9 ± 2,1g/dl et 63,6% des patients ont atteint la cible d'Hb > 11g/dl. La dose moyenne de CERA à la fin de l’étude est de 0,89 ± 0,35 µg/kg/15j. L'analyse des facteurs prédictifs montre que la réponse finale dépend du taux d'Hb initial (p = 0,002). En effet, quand le taux d'Hb initial est > 8 g/dl, le taux de réponse est de 88% vs 46% lorsque le taux d'Hb 11 g/dl sans dépasser 13 g/dl [9, 10]. Cependant, le maintien d'un taux d'hémoglobine stable nécessite du temps, des ressources humaines et financières et exige des adaptations thérapeutiques fréquentes [11]. Le méthoxy polyéthylène glycol-époétine bêta, activateur continu du récepteur de l’érythropoïétine (C.E.R.A), est un nouvel ASE qui permet la

  14. Facteurs influençant une saine alimentation chez des adolescents : revue de littérature destinée à l’infirmière en milieu scolaire

    Directory of Open Access Journals (Sweden)

    Danielle Boucher

    2008-01-01

    Full Text Available Certaines habitudes alimentaires des adolescents sont associées à une augmentation inquiétante de l’excès de poids, du nombre de cas d’obésité et du développement de maladies chroniques. Ce phénomène est maintenant considéré comme un problème majeur en santé publique. En promotion de la santé, des modèles écologiques ont été développés pour illustrer la manière dont les caractéristiques personnelles, interpersonnelles, institutionnelles, communautaires et politiques peuvent influencer les comportements. Nous avons utilisé ce modèle pour revoir les facteurs d’influence d’une saine alimentation chez des adolescents de 12 à 18 ans vivant dans des pays industrialisés. Nous avons identifié dans la littérature scientifique des facteurs individuels tels que les connaissances, l’attitude et les croyances, des facteurs interpersonnels tels que la famille et les pairs et des facteurs institutionnels tels que l’école qui peuvent influencer les choix alimentaires des adolescents. La connaissance de ces facteurs peut constituer un préalable lors du choix d’interventions pertinentes ciblant un changement de comportement et permettre ainsi aux infirmières, notamment celles œuvrant en milieu scolaire, d’intervenir plus efficacement auprès des jeunes. Les futures interventions pour promouvoir une saine alimentation pourraient donc cibler ces différents niveaux écologiques et prendre en compte leurs interactions. Le but du présent article est de faire le point sur l’état des connaissances concernant les facteurs qui influencent une saine alimentation chez les adolescents de 12 à 18 ans par le biais d’une revue de littérature dans ce domaine.

  15. Collage, montage, cut-up, musique concrète : figures de l’intégration du chaos dans l’œuvre chez William Burroughs et Pierre Schaeffer

    Directory of Open Access Journals (Sweden)

    Benoît Delaune

    2008-07-01

    Full Text Available Les pratiques de collage-montage ont été, dans la littérature et les arts du XXe siècle, l’un des moyens d’exprimer le chaos, le mouvant et l’instable. Cet article étudie l’intégration du chaos dans l’œuvre chez William Burroughs, par le biais du procédé scriptural du cut-up et d’expériences sur bande. Une comparaison avec les écrits théoriques de Pierre Schaeffer sur la musique concrète permet de mieux cerner une évolution esthétique dans l’utilisation du collage-montage en arts.In literature and the arts of the twentieth century, the practices of collage and montage have been some of the means of expressing chaos, the shifting and the unstable. This article discusses the integration of chaos in the works by William Burroughs, through the “cut-up” writing technique and tape experiments. A comparison with the theoretical writings of Pierre Schaeffer on concrete music helps identify an aesthetic evolution in the use of collage-montage in the arts.

  16. Association entre les hormones sexuelles, les marqueurs de remodelage osseux et la densité minérale osseuse chez des femmes ménopausées d'origine marocaine (étude transversale)

    Science.gov (United States)

    El Maataoui, Aissam; Biaz, Asmae; El Boukhrissi, Fatima; El Machtani, Si; Dami, Abdellah; Bouhsain, Sanae; Bamou, Youssef; El Maghraoui, Abdellah; Ouzzif, Zhor

    2015-01-01

    Introduction Le présent travail se propose d’étudier la relation entre les hormones sexuelles, notamment l’œstradiol et l'indice de l’œstradiol libre, le sulfate de déhydroépiandrosterone et la sex hormone binding globulin, les marqueurs de remodelage osseux et la densité minérale osseuse chez une population de femmes marocaine ménopausées. Méthodes Il s'agit d'une étude transversale, menée sur une période de 6 mois d'octobre 2012 à fin avril 2013 et ayant fait participer deux cent deux (202). Résultats L’œstradiol et l'indice d’œstradiol libre (IEL) ont montré une corrélation négative respectivement à l'ostéocalcine (OC), à la crosslaps (β-CTX) et l'OC (ptravail montre que l'augmentation de l’âge et la diminution de l’œstradiol libre expliquent la diminution de la DMO au niveau du col du fémur, alors que l'augmentation du taux sérique de la SHBG et la diminution du poids expliquent la diminution de la DMO au rachis lombaire. PMID:26848353

  17. Planning a multi-site, complex intervention for homeless people with mental illness: the relationships between the national team and local sites in Canada's At Home/Chez Soi project.

    Science.gov (United States)

    Nelson, Geoffrey; Macnaughton, Eric; Goering, Paula; Dudley, Michael; O'Campo, Patricia; Patterson, Michelle; Piat, Myra; Prévost, Natasha; Strehlau, Verena; Vallée, Catherine

    2013-06-01

    This research focused on the relationships between a national team and five project sites across Canada in planning a complex, community intervention for homeless people with mental illness called At Home/Chez Soi, which is based on the Housing First model. The research addressed two questions: (a) what are the challenges in planning? and (b) what factors that helped or hindered moving project planning forward? Using qualitative methods, 149 national, provincial, and local stakeholders participated in key informant or focus group interviews. We found that planning entails not only intervention and research tasks, but also relational processes that occur within an ecology of time, local context, and values. More specifically, the relationships between the national team and the project sites can be conceptualized as a collaborative process in which national and local partners bring different agendas to the planning process and must therefore listen to, negotiate, discuss, and compromise with one another. A collaborative process that involves power-sharing and having project coordinators at each site helped to bridge the differences between these two stakeholder groups, to find common ground, and to accomplish planning tasks within a compressed time frame. While local context and culture pushed towards unique adaptations of Housing First, the principles of the Housing First model provided a foundation for a common approach across sites and interventions. The implications of the findings for future planning and research of multi-site, complex, community interventions are noted.

  18. Study of contamination by 100 {mu}Ci of Sr 90 in the rat: clinical, hematological and osseous effects (appearance of osteosarcomas); Etude d'une contamination par 100 {mu}Ci de Sr 90 chez le rat: consequences cliniques, hematologiques et osseuses (apparition d'osteosarcomes)

    Energy Technology Data Exchange (ETDEWEB)

    Graf, B.; Lafuma, J.; Parmentier, C.; Parmentier, N. [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

    1968-07-01

    Clinical, hematological and osseous effects following an intramuscular injection of 100 {mu}Ci 90 Sr were studied in the rat. In spite of the magnitude of the injection and the resulting damage, the elimination of strontium could compare with what occurs after an injection at tracer doses. Comparing with the controls at the outcoming time, clinical monitoring mainly brought out a loss of body weight. Fairly early (20. - 30. day) there occurred severe hematological damage, especially on lymphocyte line, which subsided spontaneously. As foreseen, the anatomo-pathological survey of the early period showed bone and medullar lesions in the areas of enchondral ossification. In the late period, bone sarcomas occurred in nine animals out of ten. The outstanding histological type was osteogenic osteosarcomas; besides, two animals experienced bilateral tumors. (authors) [French] Les auteurs etudient les consequences cliniques, hematologiques et osseuses d'une contamination par 100 microcuries de Sr 90 injectes par voie intramusculaire chez le rat. Malgre l'importance de la contamination et les lesions consequentes, l'elimination du Sr 90 est comparable a celle que l'on observe apres injection de doses traceuses. La surveillance clinique ne met essentiellement en evidence, a la periode terminale, qu'une diminution du poids par rapport aux temoins. Les lesions hematologiques sont importantes, predominant sur la lignee lymphocytaire. Elles sont relativement precoces (20e - 30e jours) et regressent spontanement. La surveillance anatomo-pathologique de la periode precoce a montre, comme il etait previsible, des lesions osseuses et medullaires dans les zones d'ossification enchondrale. A la periode tardive, la survenue de sarcomes osseux a ete observee chez neuf animaux sur dix. Le type histologique predominant est l'osteosarcome osteogenique et il faut signaler egalement les tumeurs bilaterales observees chez deux animaux. (auteurs)

  19. Une consommation chronique élevée en sucre accélère la sarcopénie et perturbe la sensibilité à l’insuline et la stimulation post-prandiale de la synthèse protéique musculaire chez le rat âgé

    OpenAIRE

    Gatineau, Eva; Auzeloux, Isabelle; Polakof Requejo, Sergio; Dardevet, Dominique; Mosoni, Laurent

    2015-01-01

    Le vieillissement est associé à une perte de masse et de fonction musculaire appelée sarcopénie. Elle est en partie due à une altération de l’anabolisme protéique musculaire postprandial chez le sujet âgé, et notamment à une moindre stimulation de la synthèse protéique musculaire par le repas. Cette résistance anabolique est aggravée par la présence d’une inflammation à bas bruit. Elle pourrait également être liée à une diminution de la se...

  20. Experimental results concerning the metabolism of ingested iodine-131 in adult sheep under lactation; Resultats experimentaux relatifs au metabolisme de l'iode 131 ingere chez la brebis adulte en lactation

    Energy Technology Data Exchange (ETDEWEB)

    Daburon, F.; Capelle, A.; Tricaud, Y.; Nizza, P. [Commissariat a l' Energie Atomique, 92 - Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires. Departement de la Protection Sanitaire, Laboratoire-etable de Radiobiologie Appliquee

    1967-07-01

    The authors give the results of a series of experiments on metabolism of ingested iodine-131 in adult sheep under lactation; the measurement were carried out over a number of years from 1961 to 1966. The work was concerned initially with the fixation of iodine 131 in the thyroid gland, with the calculation of radiation doses absorbed and with ways of showing up any possible radiation damage in the gland. The modes of absorption of iodine 131 and its elimination through milk, urine and the faeces were then considered. Finally, a last chapter is devoted to changes in the radioactivity of the blood and of the milk, to variations of the PBI level of the blood serum as to different methods for measuring this level. (authors) [French] Les auteurs rapportent les resultats d'une serie d'experimentations relatives au metabolisme de l'iode 131 ingere chez la brebis adulte en lactation, et qui se sont etalees sur plusieurs annees, de 1961 a 1966. Les etudes ont porte d'abord sur les aspects de la fixation de l'iode 131 dans la thyroide, avec le calcul des doses de rayonnements absorbees et les moyens de mettre en evidence les radiolesions eventuelles de la glande. Ensuite ont ete traitees les modalites de l'absorption de l'iode 131 et de son elimination par le lait, les urines et les feces. Enfin un dernier chapitre a ete consacre a l'evolution de la radioactivite du sang et du lait, aux variations ainsi qu'aux divers moyens d'evaluation du taux de PBI du serum sanguin. (auteurs)

  1. Réactivation d'hépatite virale B chez un patient traité pour lymphome non hodgkinien B diffus à grandes cellules par rituximab: à propos d'un cas

    Science.gov (United States)

    Houssou, Bienvenu; Massi, Romaric Mahutondji; Camara, Marième; Mifdal, Hassan; Nourichafi, Nadia; Zafad, Saadia; Oukkache, Bouchra

    2015-01-01

    La réactivation du virus de l'hépatite B est secondaire à une diminution de l'immunité de l'hôte et peut être suivie d'une poussée d'hépatite aigue potentiellement mortelle. Nous rapportons le cas d'un patient D.H, 47 ans, sexe masculin, AgHBs négatif, jamais transfusé, jamais vacciné contre l'hépatite B qui avait présenté en mars 2013 un LNH B diffus à grandes cellules stade IV par moelle. Traité par 8 cures R-CHOP, il était en rémission complète clinique et paraclinique. Neuf mois après, il fait une rechute de son lymphome classé stade III, associée à une hépatite virale B en réplication virale (18.000 copies/mL): réactivation virale B chez porteur occulte traité avec entécavir 0.5mg par jour pendant 6 mois, l'ADN du VHB était indétectable en fin de traitement. Il avait reçu deux cures de DHAP puis deux cures R-DHAP avec une rémission complète. Lors du recueil des cellules souches en vue de l'autogreffe, l'AgHBs est à nouveau positif. Il a été greffé le 12/01/2015 et continue son traitement antiviral pour 6 mois encore. PMID:26664523

  2. Photobiological hydrogen production.

    Science.gov (United States)

    Asada, Y; Miyake, J

    1999-01-01

    The principles and recent progress in the research and development of photobiological hydrogen production are reviewed. Cyanobacteria produce hydrogen gas using nitrogenase and/or hydrogenase. Hydrogen production mediated by native hydrogenases in cyanobacteria occurs under in the dark under anaerobic conditions by degradation of intracellular glycogen. In vitro and in vivo coupling of the cyanobacterial photosynthetic system with a clostridial hydrogenase via cyanobacterial ferredoxin was demonstrated in the presence of light. Genetic transformation of Synechococcus PCC7942 with the hydrogenase gene from Clostridium pasteurianum was successful; the active enzyme was expressed in PCC7942. The strong hydrogen producers among photosynthetic bacteria were isolated and characterized. Coculture of Rhodobacter and Clostriudium was applied for hydrogen production from glucose. A mutant strain of Rhodobacter sphaeroides RV whose light-harvesting proteins were altered was obtained by UV irradiation. Hydrogen productivity by the mutant was improved when irradiated with monochromatic light of some wavelengths. The development of photobioreactors for hydrogen production is also reviewed.

  3. The study of photo-induced ultrafast dynamics in light-harvesting complex LH2 of purple bacteria

    Institute of Scientific and Technical Information of China (English)

    LIU Wei-min; YAN Yong-li; LIU Kang-jun; XU Chun-he; QIAN Shi-xiong

    2006-01-01

    In this paper,we introduce the photo-induced ultrafast dynamics taking place in the peripheral light harvesting antenna LH2 from purple bacteria Rhodobacter sphaeroides by using absorption,fluorescence emission and ultrafast spectroscopic techniques.Three kinds of LH2 sampies,pH treated LH2 (complete removal of B800 pigments),carotenoid mutated LH2 (GM 309) and electrochemical oxidation treated LH2 were used in comparison with native LH2 to investigate the mechanism of photo-induced ultrafast energy transfer within the LH2 complex.

  4. Biodegradation of azo dyes by genetically engineered azoreductase

    Institute of Scientific and Technical Information of China (English)

    WANG Jing; YAN Bin; ZHOU Ji-ti; BAO Yong-ming; LU Hong; YUAN Xiao-dong

    2005-01-01

    A azoreductase gene with 537 bp was obtained by PGR amplification from Rhodobacter sphaeroides AS1.1737. The enzyme,with a molecular weight of 18.7 kD, was efficiently expressed in Escherichia coli and its biodegradation characteristics for azo dyes were investigated. Furthermore, the reaction kinetics and mechanism of azo dyes catalyzed by the genetically engineered azoreductase were studied in detail. The presence of a hydrazo-intermediate was identified, which provided a convincing evidence for the assumption that azo dyes were degraded via an incomplete reduction stage.

  5. L’espace péruvien chez le précurseur des Indépendances Viscardo y Guzmán : inscription territoriale, parcours géographico-historique et abandon spatial

    Directory of Open Access Journals (Sweden)

    Nicolas De Ribas

    2012-01-01

    Full Text Available La réflexion émancipatrice de Juan Pablo Viscardo, le précurseur idéologique des Indépendances ibéro-américaines, va clairement s’amorcer et se façonner lorsque ce jésuite va abandonner le Cusco en 1767, et donc se confronter à un nouvel espace, l’espace européen. Par le mouvement qu’il engendre, cet exil va être un acte créateur de réflexions et de nouveaux espaces qui va instaurer alors, entre autres choses, une dialectique entre un extérieur étranger et un intérieur familier. Chez le jésuite, le voyage dans l’espace géographique est aussi la métaphore du parcours initiatique qui transforme le jeune homme et le rend progressivement conscient de qui il est. Cette connaissance de soi va alors devenir indissociable de la connaissance de la société coloniale et de la conscience de son appartenance à un espace américain à reconstruire. Ses pérégrinations en Italie et en Angleterre permettent ainsi à ce personnage historique insigne de rassembler les fragments de sa personnalité individuelle et de reformer le puzzle d’une identité collective historique.La reflexión emancipadora de Juan Pablo Viscardo, el precursor ideológico de las Independencias iberoamericanas, se inicia y se estructura cuando el jesuita abandona el Cuzco en 1767, y entonces se confronta con un nuevo espacio, el espacio europeo. Con los movimientos engendrados, este exilio es un acto creador de reflexiones y de nuevos espacios que instaura entonces, entre otras cosas, una dialéctica entre un exterior extranjero y un interior familiar. En la obra del jesuita, el viaje en el espacio geográfico es también la metáfora de un proceso iniciático que transforma al joven hombre, y gracias al cual éste toma conciencia de sí mismo. Este conocimiento de su persona se convierte en algo inseparable del conocimiento de la sociedad colonial y de la conciencia de su pertenencia a un espacio americano que hay que reconstruir. Sus viajes italianos e

  6. Diagnostic moléculaire d'helicobacter pylori par PCR chez les patients en consultation gastroentérologique au Centre Médical Saint Camille de Ouagadougou

    Science.gov (United States)

    Werme, Karidia; Bisseye, Cyrille; Ouedraogo, Issiaka; Yonli, Albert Théophane; Ouermi, Djénèba; Djigma, Florencia; Moret, Rémy; Gnoula, Charlemagne; Nikiema, Jean-Baptiste; Simpore, Jacques

    2015-01-01

    Introduction L'infection par Helicobacter pylori constitue un problème de santé publique notamment dans les pays en développement. Elle entraine une gastrite pouvant évoluer vers des formes sévères d'ulcération et de transformation maligne. La présenté étude avait pour objectif de diagnostiquer H. pylori par des techniques sérologique et moléculaire au Burkina Faso. Méthodes L’étude prospective a été conduite de mars à juin 2012 sur 70 patients venus en consultation dans le service de gastroentérologie au Centre Médical Saint Camille. Le diagnostic de H. pylori a été réalisé par le test ELISA Immunocomb (ORGENICS Ltd, Yavne, Israël) et la PCR sur des biopsies gastriques prélevées sur les patients. Résultats Les pathologies gastroduodénales étaient plus fréquentes chez les patients de plus de 45 ans. Les prévalences de H. pylori étaient respectivement de 88,57% et de 91,43% par sérologie Immunocomb et par PCR. La différence entre les deux techniques n’était pas significative (P = 0,573). La performance de la PCR a été comparée à celle de la technique Immunocomb. Les résultats montrent une sensibilité et une spécificité de 92,2% et 50,0% pour la technique Immunocomb. Conclusion Le diagnostic de H. pylori par PCR est plus spécifique que le test sérologique Immunocomb et devrait être introduit dans le diagnostic de routine de cette bactérie pathogène au Burkina Faso. PMID:26327960

  7. Facteurs associes a l'asthme sévère chez les patients asthmatiques suivis au Centre National Hospitalier de Pneumo-phtisiologie de Cotonou (Benin) en 2014

    Science.gov (United States)

    Santos, Bella Adodo Hounkpe–Dos; Gbary, Akpa Raphaël; Kpozehouen, Alphonse; Kassa, Ferdinand

    2015-01-01

    Introduction la présente étude vise à déterminer la fréquence de l'asthme sévère chez les patients asthmatiques suivis au Centre National Hospitalier de Pneumo-Phtisiologie (CNHPP) de Cotonou et identifier les facteurs de risque qui lui sont associés Méthodes l’étude transversale, descriptive et analytique a porté sur 213 patients asthmatiques de la file active 2013 du CNHPP. Les données ont été collectées par l'exploitation des dossiers et l'entretien individuel avec les patients. Elles ont été traitées et analysées à l'aide des logiciels EPIINFO7 et STATA11. Le test Chi2 de Pearson, la régression logistique uni variée et multi variée ont été utilisés au seuil de signification de 0,05 Résultats au total, 154 patients asthmatiques soit 72,7% ont répondu au questionnaire. Parmi eux 20,8% (IC95%:(14,67; 28,05)) souffraient d'asthme sévère. L’âge des patients s’étendait de 10 à 76 ans avec une médiane de 41 ans; 51,3% étaient de sexe féminin, 79,9% avaient des antécédents d'allergie, 61,7% ont commencé leur asthme après l’âge de 12 ans et seuls 11% ont consommé ou consommaient du tabac. Les facteurs associés à la survenue de l'asthme sévère étaient: l’âge de 46 à 55 ans (p = 0,04); les troisième et quatrième quintiles du bien-être économique (p = 0,01) et le début de l'asthme après l’âge de 12 ans (p < 0,001) Conclusion l’étude a montré une fréquence élevée de l'asthme sévère au Bénin et permettra d'améliorer sa prise en charge au CNHPP. PMID:26600910

  8. Déterminisme du nombre de grains chez le maïs (Zea mays L.) en déficit hydrique : rôles de la dynamique d’émergence des soies et du métabolisme carboné

    OpenAIRE

    Oury, Vincent

    2014-01-01

    L’avortement des grains est l’une des premières causes de pertes de rendement chez le maïs en déficit hydrique. Il est le plus souvent attribué à un défaut d’approvisionnement carboné des ovaires. Nous avons testé le lien entre l’avortement et i) le développement des cohortes d’ovaires, ii) la cinétique d’émergence des soies, et iii) la disponibilité en carbone pour les ovaires, caractérisée par les quantités et concentrations en métabolites carbonés, ainsi que par les activités et abondances...

  9. Quels sont les effets de l'hippothérapie sur la spasticité chez des patients atteints de lésions du système nerveux central au-delà de 12 heures post-traitement ?

    OpenAIRE

    Girard, Mélanie; GIRARDIN, Sophie; Mittaz Hager, Gaby

    2010-01-01

    Introduction : l’hippothérapie est une technique physiothérapeutique fréquemment utilisée en cas de lésions du système nerveux central (SNC). Bien que la recherche se soit considérablement développée, il n’existe, à ce jour, pas de recommandations « evidence based practice ». L’hippothérapie semble démontrer des effets positifs sur la spasticité, mais la littérature actuelle ne permet pas d’identifier leur durée chez les patients atteints de lésions du SNC. Notre travail de Bachelor se penche...

  10. Etude comparative des biomarqueurs précoces d’effets glomérulaire et tubulaire de la néphropathie diabétique chez les diabétiques type1 et 2 dans la région de Tlemcen

    OpenAIRE

    BENMANSOUR, KAMILA née BENSENANE

    2014-01-01

    La néphropathie diabétique est la première cause d’insuffisance rénale chronique terminale dans le monde, malheureusement le diagnostic de cette complication est souvent tardif. Le but de notre travail est de dépister la néphropathie diabétique avérée chez les diabétiques de la région de Tlemcen à un stade précoce par le biais des biomarqueurs précoces d’effets glomérulaire et tubulaire. Méthodes : étude transversale, analytique, descriptive et comparative menée entre Mars et Mai ...

  11. Reverse micelles as suitable microreactor for increased biohydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Pandey, Anjana [Nanotechnology and Molecular Biology Laboratory, Centre of Biotechnology, University of Allahabad, Allahabad 211002 (India); Pandey, Ashutosh [Centre of Energy Studies, MNNIT, Allahabad 211004 (India)

    2008-01-15

    Reverse micelles have been shown to act as efficient microreactors for enzymic reactions and whole cell entrapment in organic (non-aqueous) media wherein the reactants are protected from denaturation by the surrounding organic solvent. These micelles are thermodynamically stable, micrometer sized water droplets dispersed in an organic phase by a surfactant. It has been observed that when whole cells of photosynthetic bacteria (Rhodopseudomonas sphaeroides or Rhodobacter sphaeroides 2.4.1) are entrapped inside these reverse micelles, the H{sub 2} production enhanced from 25 to 35 folds. That is, 1.71mmol(mgprotein){sup -1}h{sup -1} in case of R. sphaeroides which is 25 fold higher in benzene-sodium lauryl sulfate reverse micelles. Whereas, in case of R. sphaeroides 2.4.1 the H{sub 2} production was increased by 35 fold within AOT-isooctane reverse micelles i.e. 11.5mmol(mgprotein){sup -1}h{sup -1}. The observations indicate that the entrapment of whole cells of microbes within reverse micelles provides a novel and efficient technique to produce hydrogen by the inexhaustible biological route. The two microorganisms R. sphaeroides 2.4.1 (a photosynthetic bacteria) and Citrobacter Y19 (a facultative anaerobic bacteria) together are also entrapped within AOT-isooctane and H{sub 2} production was measured i.e. 69mmol(mgprotein){sup -1}h{sup -1}. The nitrogenase enzyme responsible for hydrogen production by R. sphaeroides/R. sphaeroides 2.4.1 cells is oxygen sensitive, and very well protected within reverse micelles by the use of combined approach of two cells (R. sphaeroides 2.4.1 and Citrobacter Y19). In this case glucose present in the medium of Citrobacter Y19 serves double roles in enhancing the sustained production rate of hydrogen. Firstly, it quenches the free O{sub 2}liberated as a side product of reaction catalyzed by nitrogenase, which is O{sub 2} labile. Secondly, organic acid produced by this reaction is utilized by the Citrobacter Y19 as organic substrate in

  12. Nutrition et santé : lipides et protéines d’origine végétale - De nouvelles données pour juger de la qualité des protéines végétales chez l’homme - Implications et perspectives

    Directory of Open Access Journals (Sweden)

    Mariotti François

    2003-01-01

    Full Text Available La qualité des protéines pour l’alimentation de l’homme est un sujet très ancien mais les différentes méthodes proposées jusqu’ici pour évaluer la qualité protéique ont été largement critiquées, pour des problèmes conceptuels et méthodologiques. Depuis quelques années des avancées ont pu être faites grâce à l’emploi d’isotopes stables dans la phase postprandiale chez l’homme. Ces techniques proposent des mesures fines et conceptuellement adaptées pour évaluer la qualité des protéines et explorer le concept de qualité protéique. Ces approches ont montré que les différences globales de qualités entre sources protéiques chez l’homme au bon statut nutritionnel sont bien plus faibles que cela n’était attendu. Parallèlement, la nature des protéines alimentaires pourrait avoir des effets métaboliques plus subtils, au niveau de certains tissus ou au niveau des voies métaboliques secondaires de certains acides aminés, dont il faudra mesurer l’étendue et évaluer les conséquences physiologiques et fonctionnelles.

  13. L’exposition contrôlée à la lumière et à l’obscurité ajuste le rythme du cortisol salivaire chez les travailleurs de nuit

    Directory of Open Access Journals (Sweden)

    Anny Casademont

    2005-05-01

    Full Text Available Dans cette étude réalisée sur le terrain et en laboratoire, nous avons testé l’efficacité d’une intervention consistant à contrôler l’exposition à la lumière/obscurité de façon à favoriser l’adaptation circadienne au travail de nuit. Six travailleurs permanents de nuit (moyenne d’âge 37,1 ± σ : 8,1 ans avaient comme consigne de s’exposer de façon intermittente à une lumière blanche vive plein spectre (~2 000 lux au cours des 6 premières heures de leur quart de travail de 8 heures. Il leur était demandé de se protéger de la lumière solaire du matin avec des verres teintés (densité gris neutre, transmission visuelle de la lumière 15 % et de maintenir des épisodes réguliers de sommeil/obscurité dans une pièce très sombre. Ces épisodes devaient commencer 2 heures après la fin de chaque quart de travail de nuit. Cinq travailleurs du groupe contrôle (41,1 ± σ : 9,9 ans ont été étudiés alors qu’ils devaient uniquement maintenir un horaire régulier de sommeil/obscurité. Des procédures de routine constante, réalisées avant et après une série d’environ 12 quarts de travail de nuit s’échelonnant sur 3 semaines, ont montré chez les travailleurs du groupe traitement une variation significative dans l’heure d’apparition du pic de cortisol ainsi qu’un ajustement de ce rythme à un horaire de travail de nuit. Un plus petit changement de phase a été observé dans le groupe contrôle, ce qui suggère une adaptation partielle à l’horaire de travail de nuit. Nos résultats démontrent l’efficacité d’une exposition judicieuse à la lumière et à l’obscurité pour favoriser l’adaptation des rythmes physiologiques au travail de nuit.The efficacy of a light/darkness intervention designed to promote circadian adaptation to night shift work was tested in this combined field and laboratory study. Six permanent night shift workers (mean age: 37.1 / s: 8.1 years were instructed to

  14. La percezione del ruolo materno in madri detenute/La perception du rôle maternel chez les mères détenues/The Perception Incarcerated Mothers' Maternal role

    Directory of Open Access Journals (Sweden)

    Agostini Francesca

    2011-12-01

    Full Text Available Nel panorama nazionale ed internazionale non si discute ancora abbastanza della maternità vissuta in carcere, tuttavialargamente diffusa e quindi tema che merita opportuni approfondimenti al fine di promuovere la ricerca di strategie chegarantiscano il diritto della donna detenuta ad essere madre e il diritto dei figli a non essere privati di questo legame.Questo studio esplorativo, svolto presso la Casa Circondariale “Dozza” di Bologna, nella sezione femminile, ha avutocome obiettivo quello di indagare le caratteristiche della percezione del ruolo materno in donne detenute che non vivonocon il proprio figlio. Attraverso le interviste e l’uso di strumenti standardizzati, si è approfondito il tipo di maternitàesperita dalle donne e le difficoltà personali che la lontananza e l’ambiente frappongono alla possibilità di svolgereadeguatamente il proprio ruolo genitoriale. Pur essendo piccolo il campione, le indagini qualitative hanno consentito dievidenziare un quadro di consistente sofferenza, con utilizzo di meccanismi difensivi quali processi di idealizzazionedell’esperienza di maternità e di razionalizzazione.RésuméDans le panorama national et international, on ne discute pas encore assez de la maternité vécue en prison. Toutefois,celle-ci est largement répandue. Partant, il s’agit d’un thème qui mérite d’être approfondi afin de promouvoir larecherche de stratégies qui garantissent le droit de la femme détenue à être mère et le droit des enfants à ne pas êtreprivés de ce lien.Cette étude - réalisée dans le quartier pour femmes de la maison d’arrêt "Dozza" de Bologne - a eu comme objectifd’analyser les caractéristiques de la perception du rôle maternel chez les femmes détenues qui ne vivent pas avec leurspropres enfants. À travers les entretiens et l'usage d'instruments standardisés, nous avons approfondi le type dematernité vécue par ces femmes et les difficultés personnelles que l

  15. Le biopouvoir chez Foucault et Agamben

    Directory of Open Access Journals (Sweden)

    Katia Genel

    2012-01-01

    Full Text Available Foucault repère une transformation du pouvoir lorsque la vie entre dans ses préoccupations à partir du XVIIIe siècle. Il appelle « bio-pouvoir » les techniques spécifiques du pouvoir s’exerçant sur les corps individuels et les populations, hétérogènes aux mécanismes juridico-politiques du pouvoir souverain. Agamben, dans Homo sacer, reprend l’hypothèse foucaldienne et la fait fonctionner précisément sur le terrain délaissé par Foucault, celui de la souveraineté. La souveraineté ne porte pas à ses yeux sur des sujets de droits, mais de manière cachée sur une « vie nue », ex-ceptée par le pouvoir qui l’expose à sa violence et à sa décision souveraine. On peut alors interroger le déplacement de l’hypothèse foucaldienne opéré par Agamben et les rapports problématiques entre pouvoir souverain et bio-pouvoir, afin d’évaluer la pertinence et la fécondité de la notion de bio-pouvoir.According to Foucault, a transformation in the way of exerting power can be discerned from the 18th century onwards, as life becomes a topic of concern for power itself. « Biopower » is the term he uses to describe the new tactics of power when it focuses on life, that is to say individual bodies and populations; when such mechanisms differ from those that exert their influence in the legal and political sphere of sovereign power. In Homo sacer, Agamben takes up Foucault’s analysis and brings it into play on the very terrain that the latter wanted to break with, namely the field of sovereignty. He argues that sovereign power is not linked to rightholders, but is covertly linked to a «bare life», which is life included in the political realm by a paradoxical exclusion, exposed to the violence and the decision of sovereign power. It is consequently interesting to examine how Agamben shifts the emphasis from Foucault’s standpoint and the difficult relationship between sovereign power and biopowers, in order to assess the relevance and fruitfulness afforded by the notion of biopower.

  16. "Les Hollande" de Whistler chez Proust

    NARCIS (Netherlands)

    M. van Montfrans

    2011-01-01

    Le rôle que les portraits mondains et les marines de Whistler, l’un des modèles d’Elstir, ont joué dans la Recherche, a fait l’objet de nombreux commentaires. Il n’en est pas de même pour « les Hollande », fruit des séjours fréquents du peintre aux Pays-Bas. Les rares références aux voyages en Holla

  17. Chez nos voisins d’Outre-Rhin

    OpenAIRE

    Ettwiller, Éric

    2016-01-01

    Le tome 160 – 2012 de la Zeitschrift für die Geschichte des Oberrheins Articles Walter BerschinRolf Schmidt Eine unter dem Namen des Venantius Fortunatus auf der Reichenau überlieferte Explanatio fidei der Karolingerzeit 1-11 Klaus Gereon Beuckers Sancte Blasi, qui peregrinus his locis, sicut et ego, esse cognosceris. Zu Findan von Rheinau, der Vita Findani und der Übertragung der Blasiusreliquien in die Albzelle von St. Blasien 13-32 Adolf Laufs Reges Salici. Anmerkungen zur Historiographie ...

  18. La synchronisation des pontes chez Platax orbicularis

    OpenAIRE

    Boichard, Sylvestre

    2008-01-01

    Le contrôle des pontes est primordial en aquaculture pour démarrer une filière pérenne. Il permet en premier lieu de ne plus dépendre des pontes naturelles dont les conditions de déclenchement sont mal connues pour la plupart des espèces. Le risque de se trouver, même pendant un temps relativement court, sans aucune production d’œufs peut mettre en danger la totalité de la filière. Pour Platax orbicularis (Paraha peue en polynésien) il a été intéressant de comparer deux méthodes d’inductio...

  19. CLA et syndrome lipoatrophique chez la souris

    OpenAIRE

    Besnard Philippe; Poirier Hélène; Niot Isabelle; Guerre-Millo Michèle

    2005-01-01

    Conjugated linoleic acid (CLA) refers to a class of positional and geometric dienoic isomers of linoleic acid. Chronic dietary supplementation with a commercial mixture containing c9,t11-CLA and t10,c12-CLA in equimolar quantity leads to a drop in fat mass in various species. The t10,c12-CLA isomer is responsible for this anti-obesity effect. The reduction of fat mass is especially dramatic in the mouse, in which it is associated with a severe hyperinsulinemia, an insulin resistance and a mas...

  20. Le lecteur chez Lautréamont

    OpenAIRE

    Mauborgne, Gérard

    2007-01-01

    1. IntroductionCe qui m'a toujours le plus surpris de cette oeuvre surprenante que restent les Chants de Maldoror, c'est qu'elle ait été lue. Ce n'est pas sur le plan de sa difficulté d'approche, ou de son ésotérisme (quel que soit le sens qu'on accorde à ce mot), ou au contraire de sa relative ingénuité stylistique apparente, si on la compare au flot verbal de la critique (qui suit l'oeuvre dans le temps mais souvent en précède la lecture). Non ! C’est tout simplement sur le plan de l'histoi...

  1. Individu et individualisme chez Marguerite Yourcenar

    OpenAIRE

    2008-01-01

    Dans les œuvres de Marguerite Yourcenar, l’autonomie de l’individu se trouve remise en cause à la fois par la modernité, perçue comme un phénomène uniformisant, et par le souci de l’écrivain de découvrir les liens étroits qui unissent l’homme au reste du cosmos. Le rôle de l’individu reste cependant essentiel, dans la mesure où il apparaît comme l’unique voie d’accès à l’universel et comme le médiateur par excellence entre la dimension fragmentée de l’existence historique et les abîmes ontolo...

  2. Heterologous carotenoid-biosynthetic enzymes: functional complementation and effects on carotenoid profiles in Escherichia coli.

    Science.gov (United States)

    Song, Gyu Hyeon; Kim, Se Hyeuk; Choi, Bo Hyun; Han, Se Jong; Lee, Pyung Cheon

    2013-01-01

    A limited number of carotenoid pathway genes from microbial sources have been studied for analyzing the pathway complementation in the heterologous host Escherichia coli. In order to systematically investigate the functionality of carotenoid pathway enzymes in E. coli, the pathway genes of carotenogenic microorganisms (Brevibacterium linens, Corynebacterium glutamicum, Rhodobacter sphaeroides, Rhodobacter capsulatus, Rhodopirellula baltica, and Pantoea ananatis) were modified to form synthetic expression modules and then were complemented with Pantoea agglomerans pathway enzymes (CrtE, CrtB, CrtI, CrtY, and CrtZ). The carotenogenic pathway enzymes in the synthetic modules showed unusual activities when complemented with E. coli. For example, the expression of heterologous CrtEs of B. linens, C. glutamicum, and R. baltica influenced P. agglomerans CrtI to convert its substrate phytoene into a rare product-3,4,3',4'-tetradehydrolycopene-along with lycopene, which was an expected product, indicating that CrtE, the first enzyme in the carotenoid biosynthesis pathway, can influence carotenoid profiles. In addition, CrtIs of R. sphaeroides and R. capsulatus converted phytoene into an unusual lycopene as well as into neurosporene. Thus, this study shows that the functional complementation of pathway enzymes from different sources is a useful methodology for diversifying biosynthesis as nature does. PMID:23144136

  3. De l’impossible intimité physique à la provocation éthique : Le pouvoir subversif de l’hétérotopie carcérale chez Genet

    Directory of Open Access Journals (Sweden)

    Pascaline Hamon

    2010-09-01

    Full Text Available La représentation de l’univers carcéral tient un rôle considérable dans l’œuvre genetienne, aussi bien au niveau intra-textuel - la prison constitue la matrice d’écriture d’un certain nombre de pièces ou de romans - mais aussi au niveau extra-textuel, puisque la prison fait partie intégrante de la légende genétienne.Entre l’omniprésence littéraire et les réalités biographiques, cependant, on observe un fossé qui invite à se questionner sur les pouvoirs littéraires du lieu carcéral. En effet, deux œuvres seulement ont été écrites en prison : Notre-Dame des Fleurs et Miracle de la Rose. En constituant un miroir grossissant des questions éthiques et littéraires lié à l’écriture carcérale, ces deux œuvres permettent également de faire un lien entre une réflexion sociale, qui peut être éclairée par l’ouvrage de Michel Foucault, Surveiller et punir, et une création poétique qui repose sur le concept d’hétérotopie tel que le développe encore ce dernier dans Des espaces autres.Ces deux œuvres permettent de questionner la mise en œuvre d’une représentation carcérale à mi-chemin entre la reproduction d’une réalité sociale et une projection fantasmatique des époques, des lieux et de la littérature elle-même. Partant de la fécondité qu’offre, pour le critique littéraire, la notion d’hétérotopie, nous mettrons en lumière une dimension essentielle de la poétique genétienne : les glissements d’une époque à une autre, par le biais de l’imaginaire permettent la superposition des espaces hétérotopiques qui aboutit sur une réunion de contraires propre à susciter une interrogation éthique sur les structures sociales par le biais du scandale littéraire.La dimension anachronique permet d’expliquer les fondements de la provocation éthique telle qu’elle se manifeste chez l’auteur. Celle-ci n’est pas sans implication littéraire, puisque l’œuvre romanesque tend

  4. Metabolism of {sup 137}cesium, {sup 137}barium in the rat. Therapeutics of the contamination; Metabolisme du {sup 137}cesium, {sup 137}baryum chez le rat. Therapeutique de la contamination

    Energy Technology Data Exchange (ETDEWEB)

    Remy, J.; Philippon, A.; Lafuma, J.; Walter, C. [Commissariat a l' Energie Atomique, 92 - Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires. Departement de la Protection Sanitaire, Laboratoire de Radiopathologie

    1967-07-01

    'elimination du {sup 137}Cs - {sup 137}Ba chez le rat. Ils montrent l'independance de ces phenomenes vis-a-vis des modalites d'une administration unique. La distribution tend dans tous les cas vers un schema type qui se maintient ensuite identique a lui-meme en fonction de la charge corporelle. L'analyse biochimique de l'etat du cesium dans les milieux biologiques montre qu'il y est transporte sous une forme libre et ionisee. Abordant le probleme du mode de penetration de l'ion cesium dans le milieu intracellulaire et notamment par l'etude cinetique du systeme plasma-hematie in vivo et in vitro, les auteurs adoptent l'hypothese d'un transport actif du cesium par la membrane cellulaire. Ils en arrivent ainsi a un schema general de la distribution du cesium dans l'organisme, essentiellement caracterise par un equilibre dynamique de repartition entre deux compartiments: 99 pour cent du cesium est accumule dans le pool intracellulaire, 1 pour cent dans les liquides extracellulaires. Ce dernier compartiment est ouvert sur les emonctoires. Du fait du transport actif par les membranes cellulaires, la charge du pool intracellulaire est rapide, mais la decharge est lente. Ce phenomene est le facteur limitant de la decroissance de la charge corporelle. De ce schema les auteurs deduisent les raisons de l'echec relatif des diverses voies therapeutiques explorees a ce jour par eux-memes, et par d'autres auteurs. La stimulation des emonctoires naturels, dans le cas des diuretiques par exemple, ne saurait accroitre que l'epuration du compartiment extracellulaire. Or ce dernier ne contient que 1 pour cent de la charge corporelle et sa recharge est lente. En outre, les procedes visant a contrarier ou inhiber le transport actif du cesium par la membrane cellulaire restent, a ce jour, incompatibles avec la survie de la cellule. (auteurs)

  5. Quantification de la Charge Virale et tests de résistance du VIH-1 aux ARV à partir d’échantillons DBS (Dried Blood Spots chez des patients Guinéens sous traitement antirétroviral

    Directory of Open Access Journals (Sweden)

    Nestor Bangoura

    2015-05-01

    Full Text Available Problématique: Comme dans plusieurs pays du Sud, le suivi virologique des patients sous traitement antirétroviral (TARV en Guinée est timide voire inexistant dans certaines localités. Le but de cette étude était d’évaluer la faisabilité technique et logistique de l’utilisation des DBS dans les tests de charge virale (CV et de génotypage.Méthode: De septembre à octobre 2010, les DBS ont été préparés à partir de prélèvements sanguins de patients adultes sous TARV. Le délai d’envoi des échantillons au laboratoire de référence était de 30 jours maximum après le prélèvement et se faisait à température ambiante. La CV a été quantifiée et les échantillons de patients en échec virologique (CV ≥ 3 log10 copies/mL ont été génotypés selon le protocole de l’ANRS. L’algorithme de Stanford version 6.0.8 a été utilisé pour l’analyse et l’interprétation des mutations de résistance.Résultats: Parmi les 136 patients inclus, 129 et 7 étaient respectivement sous première et deuxième ligne de traitement avec une médiane de suivi de 35 mois [IQR: 6-108]. L’échec virologique a été noté chez 33 patients. Parmi eux, 84.8% (n = 28/33 ont bénéficié d’ungénotypage. Le taux de résistance global était de 14% (n = 19/136. Le CRF02_AG était le sous type viral le plus prévalent (82%; n = 23.Conclusion: En plus de montrer la faisabilité technique et logistique des tests de CV et de génotypage à partir des DBS, ces résultats montrent l’intérêt de leurs utilisations dans le suivi virologique des patients sous TARV. Cette étude a permis également de documenter l’échec virologique, la résistance aux ARV et la diversité génétique du VIH-1 en Guinée.Mots clés: VIH-1, Résistance aux ARV, DBS (Dried Blood Spots, Guinée Conakry, Génotypage,Charge Virale. Quantification of Viral load and resistance tests of HIV-1 to ARVs from dried blood spotssamples in Guinean patients undergoing

  6. GUIDE POUR L'INTERPRÉTATION DES ÉCAILLES ET L'ESTIMATION DE L'ÂGE CHEZ LES ALOSES (ALOSA SPP. DE LA FAÇADE ATLANTIQUE-EST ET DE LA MÉDITERRANÉE-OUEST. A GUIDE TO SCALE INTERPRETATION AND AGE ESTIMATION FOR THE EAST-ATLANTIC AND WEST-MEDITERRANEAN SHADS (ALOSA SPP..

    Directory of Open Access Journals (Sweden)

    BAGLINIÈRE J. L.

    2008-05-01

    Full Text Available L'objectif général de ce guide est de fournir un manuel d'utilisation et d'interprétation des écailles pour l'estimation de l'âge chez les aloses de l'Atlantique-Est et de Méditerranée-Ouest (Grande Alose, Alose feinte atlantique et méditerranéenne. Après un présentation rapide des espèces, populations et fleuves analysés, les écailles d'aloses et les méthodes de récolte, de préparation et de montage les concernant sont décrites en détail. Des définitions et un système de notation de l'âge standards sont donnés. La grande majorité des difficultés rencontrées pour l'interprétation des écailles sont analysées en proposant des solutions et en donnant certaines recommandations. L'ensemble de ce guide est largement illustré à l'aide d'exemples d'écailles typiques et atypiques choisis chez tous les taxons des différentes populations étudiées. The general objective of this guide is to provide a practical manual for interpreting scales and the estimation of age of Alosa from the East Atlantic and West-Mediterranean (Allis shad, Atlantic and Mediterranean shad. Following a brief presentation of the species, populations and rivers studied, the scales, sampling methods and their preparation for reading are described in detail. Definitions and a standard system of notating age are given. The majority of the difficulties encountered in the interpretation of scales are analysed, solutions proposed and some recommendations given. The whole guide is largely illustrative using examples of typical and atypical scales from the various taxons of the different populations studied.

  7. Communication: Coherences observed in vivo in photosynthetic bacteria using two-dimensional electronic spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dahlberg, Peter D. [Graduate Program in the Biophysical Sciences, Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637 (United States); Norris, Graham J.; Wang, Cheng; Viswanathan, Subha; Singh, Ved P.; Engel, Gregory S., E-mail: gsengel@uchicago.edu [Department of Chemistry, Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, Chicago, Illinois 60637 (United States)

    2015-09-14

    Energy transfer through large disordered antenna networks in photosynthetic organisms can occur with a quantum efficiency of nearly 100%. This energy transfer is facilitated by the electronic structure of the photosynthetic antennae as well as interactions between electronic states and the surrounding environment. Coherences in time-domain spectroscopy provide a fine probe of how a system interacts with its surroundings. In two-dimensional electronic spectroscopy, coherences can appear on both the ground and excited state surfaces revealing detailed information regarding electronic structure, system-bath coupling, energy transfer, and energetic coupling in complex chemical systems. Numerous studies have revealed coherences in isolated photosynthetic pigment-protein complexes, but these coherences have not been observed in vivo due to the small amplitude of these signals and the intense scatter from whole cells. Here, we present data acquired using ultrafast video-acquisition gradient-assisted photon echo spectroscopy to observe quantum beating signals from coherences in vivo. Experiments were conducted on isolated light harvesting complex II (LH2) from Rhodobacter sphaeroides, whole cells of R. sphaeroides, and whole cells of R. sphaeroides grown in 30% deuterated media. A vibronic coherence was observed following laser excitation at ambient temperature between the B850 and the B850{sup ∗} states of LH2 in each of the 3 samples with a lifetime of ∼40-60 fs.

  8. Communication: Coherences observed in vivo in photosynthetic bacteria using two-dimensional electronic spectroscopy

    Science.gov (United States)

    Dahlberg, Peter D.; Norris, Graham J.; Wang, Cheng; Viswanathan, Subha; Singh, Ved P.; Engel, Gregory S.

    2015-01-01

    Energy transfer through large disordered antenna networks in photosynthetic organisms can occur with a quantum efficiency of nearly 100%. This energy transfer is facilitated by the electronic structure of the photosynthetic antennae as well as interactions between electronic states and the surrounding environment. Coherences in time-domain spectroscopy provide a fine probe of how a system interacts with its surroundings. In two-dimensional electronic spectroscopy, coherences can appear on both the ground and excited state surfaces revealing detailed information regarding electronic structure, system-bath coupling, energy transfer, and energetic coupling in complex chemical systems. Numerous studies have revealed coherences in isolated photosynthetic pigment-protein complexes, but these coherences have not been observed in vivo due to the small amplitude of these signals and the intense scatter from whole cells. Here, we present data acquired using ultrafast video-acquisition gradient-assisted photon echo spectroscopy to observe quantum beating signals from coherences in vivo. Experiments were conducted on isolated light harvesting complex II (LH2) from Rhodobacter sphaeroides, whole cells of R. sphaeroides, and whole cells of R. sphaeroides grown in 30% deuterated media. A vibronic coherence was observed following laser excitation at ambient temperature between the B850 and the B850∗ states of LH2 in each of the 3 samples with a lifetime of ∼40-60 fs. PMID:26373989

  9. Communication: Coherences observed in vivo in photosynthetic bacteria using two-dimensional electronic spectroscopy

    International Nuclear Information System (INIS)

    Energy transfer through large disordered antenna networks in photosynthetic organisms can occur with a quantum efficiency of nearly 100%. This energy transfer is facilitated by the electronic structure of the photosynthetic antennae as well as interactions between electronic states and the surrounding environment. Coherences in time-domain spectroscopy provide a fine probe of how a system interacts with its surroundings. In two-dimensional electronic spectroscopy, coherences can appear on both the ground and excited state surfaces revealing detailed information regarding electronic structure, system-bath coupling, energy transfer, and energetic coupling in complex chemical systems. Numerous studies have revealed coherences in isolated photosynthetic pigment-protein complexes, but these coherences have not been observed in vivo due to the small amplitude of these signals and the intense scatter from whole cells. Here, we present data acquired using ultrafast video-acquisition gradient-assisted photon echo spectroscopy to observe quantum beating signals from coherences in vivo. Experiments were conducted on isolated light harvesting complex II (LH2) from Rhodobacter sphaeroides, whole cells of R. sphaeroides, and whole cells of R. sphaeroides grown in 30% deuterated media. A vibronic coherence was observed following laser excitation at ambient temperature between the B850 and the B850∗ states of LH2 in each of the 3 samples with a lifetime of ∼40-60 fs

  10. Communication: Coherences observed in vivo in photosynthetic bacteria using two-dimensional electronic spectroscopy

    Science.gov (United States)

    Dahlberg, Peter D.; Norris, Graham J.; Wang, Cheng; Viswanathan, Subha; Singh, Ved P.; Engel, Gregory S.

    2015-09-01

    Energy transfer through large disordered antenna networks in photosynthetic organisms can occur with a quantum efficiency of nearly 100%. This energy transfer is facilitated by the electronic structure of the photosynthetic antennae as well as interactions between electronic states and the surrounding environment. Coherences in time-domain spectroscopy provide a fine probe of how a system interacts with its surroundings. In two-dimensional electronic spectroscopy, coherences can appear on both the ground and excited state surfaces revealing detailed information regarding electronic structure, system-bath coupling, energy transfer, and energetic coupling in complex chemical systems. Numerous studies have revealed coherences in isolated photosynthetic pigment-protein complexes, but these coherences have not been observed in vivo due to the small amplitude of these signals and the intense scatter from whole cells. Here, we present data acquired using ultrafast video-acquisition gradient-assisted photon echo spectroscopy to observe quantum beating signals from coherences in vivo. Experiments were conducted on isolated light harvesting complex II (LH2) from Rhodobacter sphaeroides, whole cells of R. sphaeroides, and whole cells of R. sphaeroides grown in 30% deuterated media. A vibronic coherence was observed following laser excitation at ambient temperature between the B850 and the B850∗ states of LH2 in each of the 3 samples with a lifetime of ˜40-60 fs.

  11. Oxygen-­dependent regulation of bacterial lipid production

    Energy Technology Data Exchange (ETDEWEB)

    Lemmer, Kimberly C.; Dohnalkova, Alice; Noguera, Daniel R.; Donohue, Timothy J.

    2015-05-12

    Understanding the mechanisms of lipid accumulation in microorganisms is important for several reasons. In addition to providing insight into assembly of biological membranes, lipid accumulation has important applications in the production of renewable fuels and chemicals. The photosynthetic bacterium Rhodobacter sphaeroides is an attractive organism to study lipid accumulation, as it has the somewhat unique ability to increase membrane production at low O₂ tensions. Under these conditions, R. sphaeroides develops invaginations of the cytoplasmic membrane to increase its membrane surface area for housing of the membrane-bound components of its photosynthetic apparatus. Here we use fatty acid levels as a reporter of membrane lipid content. We show that, under low-O₂ and anaerobic conditions, the total fatty acid content per cell increases 3-fold. We also find that the increases in the amount of fatty acid and photosynthetic pigment per cell are correlated as O₂ tensions or light intensity are changed. To ask if lipid and pigment accumulation were genetically separable, we analyzed strains with mutations in known photosynthetic regulatory pathways. While a strain lacking AppA failed to induce photosynthetic pigment-protein complex accumulation, it increased fatty acid content under low O2 conditions. We also found that an intact PrrBA pathway is required for low O2-induced fatty acid accumulation. Our findings suggest a previously unknown role of R. sphaeroides transcriptional regulators in increasing fatty acid and phospholipid accumulation in response to decreased O₂ tension.

  12. An integrated approach to reconstructing genome-scale transcriptional regulatory networks.

    Science.gov (United States)

    Imam, Saheed; Noguera, Daniel R; Donohue, Timothy J

    2015-02-01

    Transcriptional regulatory networks (TRNs) program cells to dynamically alter their gene expression in response to changing internal or environmental conditions. In this study, we develop a novel workflow for generating large-scale TRN models that integrates comparative genomics data, global gene expression analyses, and intrinsic properties of transcription factors (TFs). An assessment of this workflow using benchmark datasets for the well-studied γ-proteobacterium Escherichia coli showed that it outperforms expression-based inference approaches, having a significantly larger area under the precision-recall curve. Further analysis indicated that this integrated workflow captures different aspects of the E. coli TRN than expression-based approaches, potentially making them highly complementary. We leveraged this new workflow and observations to build a large-scale TRN model for the α-Proteobacterium Rhodobacter sphaeroides that comprises 120 gene clusters, 1211 genes (including 93 TFs), 1858 predicted protein-DNA interactions and 76 DNA binding motifs. We found that ~67% of the predicted gene clusters in this TRN are enriched for functions ranging from photosynthesis or central carbon metabolism to environmental stress responses. We also found that members of many of the predicted gene clusters were consistent with prior knowledge in R. sphaeroides and/or other bacteria. Experimental validation of predictions from this R. sphaeroides TRN model showed that high precision and recall was also obtained for TFs involved in photosynthesis (PpsR), carbon metabolism (RSP_0489) and iron homeostasis (RSP_3341). In addition, this integrative approach enabled generation of TRNs with increased information content relative to R. sphaeroides TRN models built via other approaches. We also show how this approach can be used to simultaneously produce TRN models for each related organism used in the comparative genomics analysis. Our results highlight the advantages of integrating

  13. An integrated approach to reconstructing genome-scale transcriptional regulatory networks.

    Directory of Open Access Journals (Sweden)

    Saheed Imam

    2015-02-01

    Full Text Available Transcriptional regulatory networks (TRNs program cells to dynamically alter their gene expression in response to changing internal or environmental conditions. In this study, we develop a novel workflow for generating large-scale TRN models that integrates comparative genomics data, global gene expression analyses, and intrinsic properties of transcription factors (TFs. An assessment of this workflow using benchmark datasets for the well-studied γ-proteobacterium Escherichia coli showed that it outperforms expression-based inference approaches, having a significantly larger area under the precision-recall curve. Further analysis indicated that this integrated workflow captures different aspects of the E. coli TRN than expression-based approaches, potentially making them highly complementary. We leveraged this new workflow and observations to build a large-scale TRN model for the α-Proteobacterium Rhodobacter sphaeroides that comprises 120 gene clusters, 1211 genes (including 93 TFs, 1858 predicted protein-DNA interactions and 76 DNA binding motifs. We found that ~67% of the predicted gene clusters in this TRN are enriched for functions ranging from photosynthesis or central carbon metabolism to environmental stress responses. We also found that members of many of the predicted gene clusters were consistent with prior knowledge in R. sphaeroides and/or other bacteria. Experimental validation of predictions from this R. sphaeroides TRN model showed that high precision and recall was also obtained for TFs involved in photosynthesis (PpsR, carbon metabolism (RSP_0489 and iron homeostasis (RSP_3341. In addition, this integrative approach enabled generation of TRNs with increased information content relative to R. sphaeroides TRN models built via other approaches. We also show how this approach can be used to simultaneously produce TRN models for each related organism used in the comparative genomics analysis. Our results highlight the advantages

  14. A new method for studying iodine metabolism; the isotopic equilibrium method - kinetic and quantitative aspects of measurements made on rats; Une nouvelle methode d'etude du metabolisme de l'iode: la methode d'equilibre isotopique - aspects cinetiques et quantitatifs obtenus chez le rat

    Energy Technology Data Exchange (ETDEWEB)

    Simon, C. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1964-05-15

    The isotopic equilibrium method which has been developed in the case of the rat has made it possible to measure the absolute values of the principal parameters of iodine metabolism in this animal. The quantities and concentrations of iodine have been measured in the thyroid gland and in the plasma with a sensitivity of 0.001 {mu}g of {sup 127}I. This sensitivity has made it possible to measure pools as small as the iodide and the free iodotyrosines of the thyroid and to demonstrate the absence of free iodotyrosines in the plasma of the normal rat. In vivo, the isotopic equilibrium method has made it possible to measure the iodine content of the thyroid gland and to calculate the intensity of this gland's secretion without removing it. By double labelling with {sup 125}I and {sup 131}I the isotopic equilibrium method has made it possible to measure the flux, intensity of the intrathyroidal recycling as well as the turnover rates of all the iodine containing compounds of the thyroid gland. For this gland no precursor-product relationship has been found between The iodotyrosines (MIT and DIT) and the iodothyronines (T{sub 4} and T{sub 3}). The absence of this relationship is due to the heterogeneity of the thyroglobulin turnover. It has been shown furthermore that there exists in the plasma an organic fraction of the iodine which is different to thyroglobulin and which is renewed more rapidly than the circulating hormones T{sub 3} and T{sub 4}. The isotopic equilibrium method is very useful for series measurements of iodine. It makes it possible furthermore to improve the biochemical fractionations by adding carriers without affecting the subsequent {sup 127}I measurements. (author) [French] La methode d'equilibre isotopique, mise au point chez le rat, a permis de mesurer en valeur absolue les principaux parametres du metabolisme de l'iode chez cet animal. Les quantites ou les concentrations d'iode ont ete mesurees pour la thyroide et pour le

  15. Aspects épidémiologiques, cliniques, cytologiques et immunophénotypiques des leucémies aiguës chez les enfants: expérience du laboratoire d'hématologie du Centre Hospitalier Universitaire IBN Sina

    Science.gov (United States)

    Doumbia, Mariam; Uwingabiye, Jean; Bissan, Aboubacar; Rachid, Razine; Benkirane, Souad; Masrar, Azlarab

    2016-01-01

    L'objectif de ce travail était de décrire les caractéristiques épidémiologiques, cytologiques et immunophénotypiques des leucémies aigues (LA) chez les enfants diagnostiqués au Centre Hospitalo-universitaire (CHU) Ibn Sina et de déterminer aussi la concordance entre les résultats de la cytologie à ceux de l'immunophénotypage. Il s'agit d'une étude transversale réalisée au laboratoire d'hématologie du CHU Ibn Sina entre Juin 2012 et Mai 2014. Parmi 104 cas de LA diagnostiqués, 52% étaient des garçons avec un sex-ratio H/F= 1,32 et l’âge médian de 5,7 ans. La répartition des différents types de LA était: LA lymphoïde (LAL) (74%), LA myéloïde(LAM) (20,2%), LA biphénotypique(LAB) (65,8%). Parmi les LAL,78% ont été classé LAL B et 22% comme LALT. Les signes cliniques étaient principalement présentés par le syndrome tumoral (73,1%), la fièvre (61%) et syndrome hémorragique (50%). Les anomalies de l'hémogrammeles plus fréquents étaient: thrombopénie (89,4%), anémie (86,5%), hyperleucocytose (79,8%). Le taux des blastes périphérique et médullaires était statistiquement élevé pour LAL que pour LAM et LAB (p<0,001). Le taux de rechute et de mortalité était respectivement de 21,2% et16, 3%. Le taux de concordance entre les résultats de la cytologie et ceux de l'immunophénotypage était de 92,7% pour LAL et de 82,6% pour LAM. Le diagnostic des LA se base toujours en premier sur la cytologie. L'immunophénotypage nous a permis de faire une meilleure distinction entre les leucémies aiguës. La prise en charge des LA pédiatriques est un problème majeur qui nécessite les centres spécialisés. PMID:27516823

  16. Jean Bruller, dessinateur et illustrateur de la littérature coloniale pour la jeunesse de l’entre-deux-guerres : de Loulou chez les nègres (1929 à Baba Diène et Morceau-de-Sucre (1937

    Directory of Open Access Journals (Sweden)

    Nathalie Gibert-Joly

    2012-01-01

    Full Text Available Cet article vise à mettre en exergue l’évolution des prises de position contre le colonialisme du dessinateur Jean Bruller, futur écrivain Vercors (1902-1991, dans l’entre-deux-guerres. L’Appel des 121 que Vercors signa sans hésiter en 1960 pour clamer publiquement le droit à l'insoumission dans la guerre d'Algérie, son combat dès 1955 en faveur de l’indépendance de ce pays pourraient nous conduire à une interprétation rétrospective erronée, celle d’un homme et d’un mythe de la résistance anticolonialiste dès le début de l’entrée dans l’âge adulte et dans son parcours artistique vecteur de cette pensée. Les illustrations qu’il fournit pour la littérature de jeunesse de l’entre-deux-guerres, mais aussi l’une de ses créations personnelles prouvent au contraire que le dessinateur bascula d’une acceptation inconsciente à une interrogation critique du colonialisme du début des années vingt à la fin des années trente. De l’empan de Loulou chez les nègres à Baba Diène et Morceau-de-Sucre, nous distinguerons trois moments marqués par la publication d’ouvrages-clés pour comprendre la prise de conscience graduelle de Jean Bruller, visible dans ses choix collaboratifs comme dans les rapports entre le texte et ses dessins. Il est nécessaire de le situer dans un temps autant personnel qu’historique : celui d’un jeune homme dans un milieu éducatif et social donné, mais suffisamment attentif au monde pour avoir les moyens de s’en émanciper ; celui de l’artiste dans ses réalités symboliques et économiques, influencé par des réseaux de sociabilité correspondant à certains de ses idéaux ; celui d’artistes et d’écrivains qui s’interrogent, d’intellectuels qui prennent des positions de plus en plus tranchées au cours de ces années-là.

  17. Synthetic Antenna Functioning As Light Harvester in the Whole Visible Region for Enhanced Hybrid Photosynthetic Reaction Centers.

    Science.gov (United States)

    Hassan Omar, Omar; la Gatta, Simona; Tangorra, Rocco Roberto; Milano, Francesco; Ragni, Roberta; Operamolla, Alessandra; Argazzi, Roberto; Chiorboli, Claudio; Agostiano, Angela; Trotta, Massimo; Farinola, Gianluca M

    2016-07-20

    The photosynthetic reaction center (RC) from the Rhodobacter sphaeroides bacterium has been covalently bioconjugated with a NIR-emitting fluorophore (AE800) whose synthesis was specifically tailored to act as artificial antenna harvesting light in the entire visible region. AE800 has a broad absorption spectrum with peaks centered in the absorption gaps of the RC and its emission overlaps the most intense RC absorption bands, ensuring a consistent increase of the protein optical cross section. The covalent hybrid AE800-RC is stable and fully functional. The energy collected by the artificial antenna is transferred to the protein via FRET mechanism, and the hybrid system outperforms by a noteworthy 30% the overall photochemical activity of the native protein under the entire range of visible light. This improvement in the optical characteristic of the photoenzyme demonstrates the effectiveness of the bioconjugation approach as a suitable route to new biohybrid materials for energy conversion, photocatalysis, and biosensing.

  18. Synthetic Antenna Functioning As Light Harvester in the Whole Visible Region for Enhanced Hybrid Photosynthetic Reaction Centers.

    Science.gov (United States)

    Hassan Omar, Omar; la Gatta, Simona; Tangorra, Rocco Roberto; Milano, Francesco; Ragni, Roberta; Operamolla, Alessandra; Argazzi, Roberto; Chiorboli, Claudio; Agostiano, Angela; Trotta, Massimo; Farinola, Gianluca M

    2016-07-20

    The photosynthetic reaction center (RC) from the Rhodobacter sphaeroides bacterium has been covalently bioconjugated with a NIR-emitting fluorophore (AE800) whose synthesis was specifically tailored to act as artificial antenna harvesting light in the entire visible region. AE800 has a broad absorption spectrum with peaks centered in the absorption gaps of the RC and its emission overlaps the most intense RC absorption bands, ensuring a consistent increase of the protein optical cross section. The covalent hybrid AE800-RC is stable and fully functional. The energy collected by the artificial antenna is transferred to the protein via FRET mechanism, and the hybrid system outperforms by a noteworthy 30% the overall photochemical activity of the native protein under the entire range of visible light. This improvement in the optical characteristic of the photoenzyme demonstrates the effectiveness of the bioconjugation approach as a suitable route to new biohybrid materials for energy conversion, photocatalysis, and biosensing. PMID:27245093

  19. Use of Engineered Unique Cysteine Residues to Facilitate Oriented Coupling of Proteins Directly to a Gold Substrate

    Energy Technology Data Exchange (ETDEWEB)

    Magis, Gerhard J.; Olsen, John D.; Reynolds, Nicholas P.; Leggett, Graham J.; Hunter, C Neil; Aartsma, Thijs J.; Frese, Raoul N.

    2011-07-28

    A prerequisite for any “lab on a chip” device that utilizes an electrical signal from the sensor protein is the ability to attach the protein in a specific orientation onto a conducting substrate. Here, we demonstrate the covalent attachment to a gold surface of light-harvesting membrane proteins, from Rhodobacter sphaeroides, via cysteine (Cys) residues engineered on either the cytoplasmic or periplasmic face. This simple directed attachment is superior in its ability to retain light-harvesting complex (LHC) function, when compared to a similar attachment procedure utilizing a self-assembled monolayer on gold. LH 1 has previously been observed to have superior photostability over LH 2 (Magis et al. [2010] Biochim. Biophys. Acta, 1798, 637–645); this characteristic is maintained even with the introduction of Cys residues.

  20. An unexpected negative influence of light intensity on hydrogen production by dark fermentative bacteria Clostridium beijerinckii.

    Science.gov (United States)

    Zagrodnik, R; Laniecki, M

    2016-01-01

    The role of light intensity on biohydrogen production from glucose by Clostridium beijerinckii, Clostridium acetobutylicum, and Rhodobacter sphaeroides was studied to evaluate the performance and possible application in co-culture fermentation system. The applied source of light had spectrum similar to the solar radiation. The influence of light intensity on hydrogen production in dark process by C. acetobutylicum was negligible. In contrast, dark fermentation by C. beijerinckii bacteria showed a significant decrease (83%) in produced hydrogen at light intensity of 540W/m(2). Here, the redirection of metabolism from acetic and butyric acid formation towards lactic acid was observed. This not yet reported effect was probably caused by irradiation of these bacteria by light within UVA range, which is an important component of the solar radiation. The excessive illumination with light of intensity higher than 200W/m(2) resulted in decrease in hydrogen production with photofermentative bacteria as well. PMID:26602144

  1. Breeding of Coenzyme Q10 High Yield Strain%发酵生产辅酶Q10高产菌株的选育

    Institute of Scientific and Technical Information of China (English)

    陈金卿

    2016-01-01

    以实验室保存的类球红细菌(Rhodobacter sphaeroides)JDW61为出发菌株,考察了紫外、紫外结合氯化锂和亚硝基胍对菌株产生辅酶Q10能力的诱变效应,并结合辅酶Q10的合成途径设计了快速筛选辅酶Q10高产菌株的模型,获得一株辅酶Q10产量提高的突变株CP222,该菌株摇瓶发酵的辅酶Q10产量为276.14 mg·L-1,较出发菌株提高了190%,并且遗传性能稳定.

  2. Photoprotection Mechanism of Light-Harvesting Antenna Complex from Purple Bacteria.

    Science.gov (United States)

    Kosumi, Daisuke; Horibe, Tomoko; Sugisaki, Mitsuru; Cogdell, Richard J; Hashimoto, Hideki

    2016-02-11

    Photosynthetic light-harvesting apparatus efficiently capture sunlight and transfer the energy to reaction centers, while they safely dissipate excess energy to surrounding environments for a protection of their organisms. In this study, we performed pump-probe spectroscopic measurements with a temporal window ranging from femtosecond to submillisecond on the purple bacterial antenna complex LH2 from Rhodobacter sphaeroides 2.4.1 to clarify its photoprotection functions. The observed excited state dynamics in the time range from subnanosecond to microsecond exhibits that the triplet-triplet excitation energy transfer from bacteriochlorophyll a to carotenoid takes place with a time constant of 16.7 ns. Furthermore, ultrafast spectroscopic data suggests that a molecular assembly of bacteriochlorophyll a in LH2 efficiently suppresses a generation of triple bacteriochlorophyll a.

  3. Comparison of different mixed cultures for bio-hydrogen production from ground wheat starch by combined dark and light fermentation.

    Science.gov (United States)

    Ozmihci, Serpil; Kargi, Fikret

    2010-04-01

    Composition of the mixed culture was varied in combined dark-light fermentation of wheat powder starch in order to improve hydrogen gas formation rate and yield. Heat-treated anaerobic sludge and pure culture of Clostridium beijerinckii (DSMZ 791T) were combined with two different light fermentation bacteria of Rhodobacter sphaeroides (RS-NRRL and RS-RV) in order to select a more suitable mixture resulting in high hydrogen yield and formation rate. A combination of the anaerobic sludge and RS-NRRL yielded the highest cumulative hydrogen (CHF = 140 ml), the highest yield (0.36 mol H2 mol(-1) glucose) and specific hydrogen formation rate (2.5 ml H2 g(-1) biomass h(-1)). During dark fermentation (70 h) hydrogen was produced simultaneously by the dark and light fermentation bacteria using glucose from hydrolyzed starch. However, only light fermentation bacteria produced hydrogen from VFA's derived from dark fermentation after a long adaptation period.

  4. Fabrication of biomolecule copolymer hybrid nanovesicles as energy conversion systems

    Science.gov (United States)

    Ho, Dean; Chu, Benjamin; Lee, Hyeseung; Brooks, Evan K.; Kuo, Karen; Montemagno, Carlo D.

    2005-12-01

    This work demonstrates the integration of the energy-transducing proteins bacteriorhodopsin (BR) from Halobacterium halobium and cytochrome c oxidase (COX) from Rhodobacter sphaeroides into block copolymeric vesicles towards the demonstration of coupled protein functionality. An ABA triblock copolymer-based biomimetic membrane possessing UV-curable acrylate endgroups was synthesized to serve as a robust matrix for protein reconstitution. BR-functionalized polymers were shown to generate light-driven transmembrane pH gradients while pH gradient-induced electron release was observed from COX-functionalized polymers. Cooperative behaviour observed from composite membrane functionalized by both proteins revealed the generation of microamp-range currents with no applied voltage. As such, it has been shown that the fruition of technologies based upon bio-functionalizing abiotic materials may contribute to the realization of high power density devices inspired by nature.

  5. Dicty_cDB: Contig-U04692-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available 115 |pid:none) Rhodococcus opacus B4 DNA, comp... 35 3.7 CP000615_332( CP000615 |pid:none) Burkholderia vietnam...4.8 CP001150_901( CP001150 |pid:none) Rhodobacter sphaeroides KD131 ch... 34 4.8 CP000614_233( CP000614 |pid:none) Burkholderia vietn...none) Pelobacter propionicus DSM 2379... 44 0.005 CR382132_780( CR382132 |pid:none) Yarrowia lipolytica stra...001437 |pid:none) Clostridium acetobutylicum ATCC... 37 0.56 ( Q25802 ) RecName: Full=DNA-directed RNA polymerase subunit... comple... 35 2.8 T18869( T18869 ) hypothetical protein C03A3.3 - Caenorhabditis ele... 35 2.8 BA000028_204(

  6. 光合细菌对土壤中呋喃丹的生物降解%Characterization of Biodegradation for Carbofuran Pesticides in Soils by Photosynthetic Bacteria

    Institute of Scientific and Technical Information of China (English)

    白红娟; 肖根林; 贾万利

    2013-01-01

    以一株降解呋喃丹的光合细菌球形红细菌(Rhodobacter sphaeroides)H菌株为材料,考察了其在实验室模拟条件下降解土壤中呋喃丹的影响因素及其动力学过程.结果表明,该菌降解呋喃丹的最适条件为:温度30℃,pH=7.0,接种量107个/g.在最适条件下,H菌株对初始质量浓度为5.0~25 mg/kg呋喃丹的降解反应均符合一级动力学特征.可以将其应用于呋喃丹污染土壤的生物修复.

  7. The Brucella abortus cyclic beta-1,2-glucan virulence factor is substituted with O-ester-linked succinyl residues.

    Science.gov (United States)

    Roset, Mara S; Ciocchini, Andrés E; Ugalde, Rodolfo A; Iñón de Iannino, Nora

    2006-07-01

    Brucella periplasmic cyclic beta-1,2-glucan plays an important role during bacterium-host interaction. Nuclear magnetic resonance spectrometry analysis, thin-layer chromatography, and DEAE-Sephadex chromatography were used to characterize Brucella abortus cyclic glucan. In the present study, we report that a fraction of B. abortus cyclic beta-1,2-glucan is substituted with succinyl residues, which confer anionic character on the cyclic beta-1,2-glucan. The oligosaccharide backbone is substituted at C-6 positions with an average of two succinyl residues per glucan molecule. This O-ester-linked succinyl residue is the only substituent of Brucella cyclic glucan. A B. abortus open reading frame (BAB1_1718) homologous to Rhodobacter sphaeroides glucan succinyltransferase (OpgC) was identified as the gene encoding the enzyme responsible for cyclic glucan modification. This gene was named cgm for cyclic glucan modifier and is highly conserved in Brucella melitensis and Brucella suis. Nucleotide sequencing revealed that B. abortus cgm consists of a 1,182-bp open reading frame coding for a predicted membrane protein of 393 amino acid residues (42.7 kDa) 39% identical to Rhodobacter sphaeroides succinyltransferase. cgm null mutants in B. abortus strains 2308 and S19 produced neutral glucans without succinyl residues, confirming the identity of this protein as the cyclic-glucan succinyltransferase enzyme. In this study, we demonstrate that succinyl substituents of cyclic beta-1,2-glucan of B. abortus are necessary for hypo-osmotic adaptation. On the other hand, intracellular multiplication and mouse spleen colonization are not affected in cgm mutants, indicating that cyclic-beta-1,2-glucan succinylation is not required for virulence and suggesting that no low-osmotic stress conditions must be overcome during infection. PMID:16816173

  8. Magnetic resonance imaging in primates. The example of the mouse lemur (Microcebus murinus: From detection of pathological aging to therapeutic evaluations Imagerie par résonance magnétique chez les primates. L’exemple du microcèbe murin (Microcebus murinus : De la détection du vieillissement cérébral pathologique à l'évaluation thérapeutique

    Directory of Open Access Journals (Sweden)

    Nadine El Tannir El Tayara

    2011-02-01

    also be used during therapeutic interventions by selecting animals to be involved in therapeutic trials and also by following specific MR biomarkers. MRI is thus critical to better characterize cerebral aging in the mouse lemur and to better carry out longitudinal studies in this primate model.Le vieillissement cérébral est un problème majeur de santé public. Il est associé dans certains cas à des maladies neurodégénératives telles que la maladie d’Alzheimer (MA. La compréhension de la physiopathologie du vieillissement cérébral et l'évaluation de nouvelles thérapies nécessitent l’utilisation de modèles animaux. Les souris transgéniques sont très utilisées mais restent peu représentatives de l’ensemble des aspects des maladies humaines. Les modèles primates sont plus proches phylogénétiquement de l’homme et sont plus prédictifs de l’efficacité de médicaments chez l'homme. Le microcèbe murin est un petit primate (environ 12cm, 100g qui est un modèle de vieillissement cérébral et un modèle potentiel de la MA. En effet certains animaux développent avec l’âge des altérations cérébrales telles que de l’amyloïdose. Des méthodes d'imagerie non-invasives comme l’imagerie par résonance magnétique (IRM peuvent être utilisées pour étudier les altérations cérébrales chez ces animaux. Nous montrons ici comment l'IRM permet d'étudier le microcèbe et présentons l'utilisation de l'IRM pour l'évaluation de thérapies et d'autres applications. Chez le microcèbe, l’IRM a permis de décrire l’anatomie cérébrale, le système vasculaire cérébral (grâce à l’angiographie par RMN et aussi de caractériser l’atrophie cérébrale liée à l’âge ainsi que des processus entraînant une accumulation de fer intracérébrale. La consommation cérébrale de glucose a aussi pu être étudiée par une autre modalité d’imagerie in vivo, la tomographie par émission de positons (TEP. Dans ce cas, l’IRM sert de support

  9. Improved hydrogen production by coupled systems of hydrogenase negative photosynthetic bacteria and fermentative bacteria in reverse micelles

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Anita [Centre for Biotechnology, University of Allahabad, Allahabad 211002 (India); Misra, Krishna [Indo-Russian Center for Bioinformatics, Indian Institute of Information Technology, Allahabad 211011 (India)

    2008-11-15

    Significant improvement in biological hydrogen production is achieved by the use of coupled bacterial cells in reverse micellar systems. Two coupled systems (a) Rhodopseudomonas palustris CGA009/Citrobacter Y19, and (b) Rhodobacter sphaeroides 2.4.1/Citrobacter Y19 bacteria have been immobilized separately in aqueous pool of the reverse micelles fabricated by various surfactants (AOT, CBAC and SDS) and apolar organic solvents (benzene and isooctane). The gene for uptake hydrogenase enzyme has been manipulated further for hydrogen generation. Mutants deficient in uptake hydrogenase (Hup{sup -}) were obtained from R. palustris CGA009 and R. sphaeroides 2.4.1, and entrapped with Citrobacter Y19 in the reverse micellar systems. More than two fold increase in hydrogen production was obtained by the use of Hup{sup -} mutants instead of wild-type photosynthetic bacteria together with Citrobacter Y19. Addition of sodium dithionite, a reducing agent to AOT/H{sub 2}O/isooctane reverse micellar system with the coupled systems of wild-type photosynthetic bacteria and fermentative bacterium Y19 effected similar increase in hydrogen production rate as it is obtained by the use of mutants. CBAC/H{sub 2}O/isooctane reverse micellar system is used for the first time for hydrogen production and is as promising as AOT/H{sub 2}O/isooctane reverse micellar system. All reverse micellar systems of coupled bacterial cultures gave encouraging hydrogen production (rate as well as yield) compared to uncoupled bacterial culture. (author)

  10. Light-field-characterization in a continuous hydrogen-producing photobioreactor by optical simulation and computational fluid dynamics.

    Science.gov (United States)

    Krujatz, Felix; Illing, Rico; Krautwer, Tobias; Liao, Jing; Helbig, Karsten; Goy, Katharina; Opitz, Jörg; Cuniberti, Gianaurelio; Bley, Thomas; Weber, Jost

    2015-12-01

    Externally illuminated photobioreactors (PBRs) are widely used in studies on the use of phototrophic microorganisms as sources of bioenergy and other photobiotechnology research. In this work, straightforward simulation techniques were used to describe effects of varying fluid flow conditions in a continuous hydrogen-producing PBR on the rate of photofermentative hydrogen production (rH2 ) by Rhodobacter sphaeroides DSM 158. A ZEMAX optical ray tracing simulation was performed to quantify the illumination intensity reaching the interior of the cylindrical PBR vessel. 24.2% of the emitted energy was lost through optical effects, or did not reach the PBR surface. In a dense culture of continuously producing bacteria during chemostatic cultivation, the illumination intensity became completely attenuated within the first centimeter of the PBR radius as described by an empirical three-parametric model implemented in Mathcad. The bacterial movement in chemostatic steady-state conditions was influenced by varying the fluid Reynolds number. The "Computational Fluid Dynamics" and "Particle Tracing" tools of COMSOL Multiphysics were used to visualize the fluid flow pattern and cellular trajectories through well-illuminated zones near the PBR periphery and dark zones in the center of the PBR. A moderate turbulence (Reynolds number = 12,600) and fluctuating illumination of 1.5 Hz were found to yield the highest continuous rH2 by R. sphaeroides DSM 158 (170.5 mL L(-1) h(-1) ) in this study.

  11. Enhanced Hydrogen Production by Co-cultures of Hydrogenase and Nitrogenase in Escherichia coli.

    Science.gov (United States)

    Lee, Hyun Jeong; Sekhon, Simranjeet Singh; Kim, Young Su; Park, Ju-Yong; Kim, Yang-Hoon; Min, Jiho

    2016-03-01

    Rhodobacter sphaeroides is a bacterium that can produce hydrogen by interaction with hydrogenase and nitrogenase. We report a hydrogen production system using co-cultivation of hydrogenase in liquid medium and immobilized nitrogenase in Escherichia coli. The recombinant plasmid has been constructed to analyze the effect of hydrogen production on the expression of hupSL hydrogenase and nifHDK nitrogenase isolated from R. sphaeroides. All recombinant E. coli strains were cultured anaerobically, and cells for nitrogenase were immobilized in agar gel, whereas cells for hydrogenase were supplemented on the nitrogenase agar gel. The hupSL hydrogenase has been observed to enhance hydrogen production and hydrogenase activity under co-culture with nifHDK nitrogenase. The maximum hydrogen production has been obtained at an agar gel concentration and a cell concentration for co-culture of 2 % and 6.4 × 10(8) CFU. Thus, co-culture of hupSL hydrogenase and nifHDK nitrogenase provides a promising route for enhancing the hydrogen production and hydrogenase activity.

  12. Regulation of bacterial photosynthesis genes by the small noncoding RNA PcrZ.

    Science.gov (United States)

    Mank, Nils N; Berghoff, Bork A; Hermanns, Yannick N; Klug, Gabriele

    2012-10-01

    The small RNA PcrZ (photosynthesis control RNA Z) of the facultative phototrophic bacterium Rhodobacter sphaeroides is induced upon a drop of oxygen tension with similar kinetics to those of genes for components of photosynthetic complexes. High expression of PcrZ depends on PrrA, the response regulator of the PrrB/PrrA two-component system with a central role in redox regulation in R. sphaeroides. In addition the FnrL protein, an activator of some photosynthesis genes at low oxygen tension, is involved in redox-dependent expression of this small (s)RNA. Overexpression of full-length PcrZ in R. sphaeroides affects expression of a small subset of genes, most of them with a function in photosynthesis. Some mRNAs from the photosynthetic gene cluster were predicted to be putative PcrZ targets and results from an in vivo reporter system support these predictions. Our data reveal a negative effect of PcrZ on expression of its target mRNAs. Thus, PcrZ counteracts the redox-dependent induction of photosynthesis genes, which is mediated by protein regulators. Because PrrA directly activates photosynthesis genes and at the same time PcrZ, which negatively affects photosynthesis gene expression, this is one of the rare cases of an incoherent feed-forward loop including an sRNA. Our data identified PcrZ as a trans acting sRNA with a direct regulatory function in formation of photosynthetic complexes and provide a model for the control of photosynthesis gene expression by a regulatory network consisting of proteins and a small noncoding RNA.

  13. Formación del pensamiento reflexivo en estudiantes universitarios (Training Reflexive Thinking in University Students (Formation de la pensée réflexive chez les étudiants universitaires (Formação do pensamento reflexivo em estudantes universitários

    Directory of Open Access Journals (Sweden)

    Claudia Ximena González-Moreno

    2012-06-01

    Full Text Available ResumenSe parte del soporte científico y conceptual del enfo- que histórico-cultural de Lev Semiónovich Vygotsky para presentar los resultados de una investigación des- criptiva, sobre el quehacer educativo en el aula por lo que se establece una interacción dialéctica entre teoría y práctica. El objetivo fue la formación del pensamien- to reflexivo en estudiantes universitarios en la licencia- tura en Pedagogía Infantil, en la clase Teorías cogniti- vas del aprendizaje. Los resultados muestran que las acciones pedagógicas pueden impactar positivamente la consolidación de los procesos de aprendizaje y que el pensamiento reflexivo se constituye en el motor del cambio mediante el uso intencionado del lenguaje.AbstractThe starting point of this paper is the scien- tific and conceptual framework of Vygotsky's cultural-historical approach, which is used to present the results of a descriptive research work on classroom activities, establishing a dialectic interaction between theory and practice. The aim was to train reflexive thin- king in university students of the teacher training course in Children's Pedagogy, more specifically a subject in Cognitive Theories of Learning. The results show that pedagogical actions can have a positive impact on the consolidation of learning processes. Reflexive thinking is an agent of change through inten- tional use of language.RésuméLe point de départ de cette étude est la base scientifique et conceptuelle de la perspective historico-culturelle de Vygotsky pour présen- ter les résultats d'une recherche de type des- criptive, par rapport au travail éducatif dans la salle de classe, c'est pourquoi on a établit l'interaction dialectique entre la théorie et la pratique. L'objectif a été la formation de la pensée réflexive chez les étudiants univer- sitaires dans la carrière de Pédagogie pour l'enfance, à travers le cours Théories Cogni- tives de l'apprentissage. Les résultats mon- trent

  14. Representaciones sociales de la computadora en usuarios semirrurales de México (Social Representations of Semirural Computer Users of Mexico (Les représentations sociales de l′ordinateur chez les usagers semi-ruraux au Méxique (Representações sociais do computador em usuários semirrurais do México

    Directory of Open Access Journals (Sweden)

    Marco Antoniog González-Pérez

    2012-12-01

    Full Text Available ResumenEste artículo de investigación se deriva de un estudio de campo realizado para identificar representaciones sociales (RS de la computadora en usuarios de los Centros Comunitarios de Aprendizaje del Instituto Tecnológico y de Estudios Superiores de Monterrey, ITESM. Se aplicaron dos instrumentos: prueba de aso- ciación libre y guion de entrevista a muestras de 217 sujetos, en la primera condición y 31, en la segunda. El estudio se realizó en Chapa de Mota y Villas del Car- bón, Estado de México. Se mostraron representacio- nes sociales, RS, cambiantes entre usuarios con base en edad y tiempo de uso y se observó cómo los miem- bros de la comunidad insertan la computadora en sus actividades cotidianas.AbstractThis research article is derived from a field study conducted to identify social representations (SR of the computer users of Community Learning Centers at ITESM. The instruments used were: free association test and interview script to samples of 217 subjects in the first condition and 31 in the sec- ond one. The study was conducted in Chapa de Mota and Villas del Carbón, Estado de México. SR were chang- ing between users based on age and length of use and showed how com- munity members used the computer in their daily activities.RésuméCet article de recherche découle d'une étude dans le terrain réalisée pour identifier les représentations sociales (RS de l’ordinateur chez les usagers des Centres Communautaires d’ap- prentissage dans le Tecnológico de Monterrey (Technologique de Mon- terrey. On a appliqué deux outils: la preuve d’association libre à 217 per- sonnes et le scenario d’entretien à 31 personnes. Les résultats ont montrés des représentations sociales chan- geantes en fonction de l’âge et le temps d’usage et on a observé com- ment les membres de la communauté utilisent l’ordinateur dans leurs activi- tés au quotidien.ResumoEste artigo se deriva de uma pesqui- sa de campo realizada

  15. Bio-hydrogen production from ground wheat starch by continuous combined fermentation using annular-hybrid bioreactor

    Energy Technology Data Exchange (ETDEWEB)

    Argun, Hidayet; Kargi, Fikret [Department of Environmental Engineering, Dokuz Eylul University, Buca, Izmir (Turkey)

    2010-06-15

    Continuous combined fermentation of ground wheat starch was realized in an annular-hybrid bioreactor (AHB) for hydrogen gas production. A mixture of pure cultures of Clostridium beijerinkii (DSMZ-791) and Rhodobacter sphaeroides-RV were used as seed cultures in combined fermentation. The feed contained 5 g L{sup -1} ground wheat with some nutrient supplementation. Effects of hydraulic residence time (HRT) on the rate and yield of hydrogen gas formation were investigated. Steady-state daily hydrogen production decreased but, hydrogen yield increased with increasing HRT. The highest hydrogen yield was 90 ml g{sup -1} starch at HRT of 6 days. Hydrolysis of starch and fermentation of glucose to volatile fatty acids (VFA) were readily realized at all HRTs. However, slow conversion of VFAs to H{sub 2} and CO{sub 2} by photo-fermentation caused accumulation of VFAs in the medium. Specific and volumetric rates of hydrogen formation also decreased with increasing HRT. High hydrogen yields obtained at high HRTs are due to partial fermentation of VFAs by Rhodobacter sp. The system should be operated at HRTs longer than 5 days for effective hydrogen gas formation by the dark and photo-fermentation bacteria. (author)

  16. L'obscurité du sens chez Clauberg

    Directory of Open Access Journals (Sweden)

    Guillaume Coqui

    2007-07-01

    Full Text Available On examine ici les principaux linéaments de l'herméneutique de Johannes Clauberg, notamment à travers la structure de sa Logica Vetus et Nova et le modèle qu'elle propose de l'analyse de la " phrase obscure ". La thèse soutenue est que si Clauberg place essentiellement dans le lexique, et non dans la syntaxe, les racines de l'ambiguïté et de l'obscurité des énoncés, c'est que sa conception du langage et de la pensée les rend trop isomorphes l'un à l'autre pour qu'une obscurité proprement syntaxique puisse être conçue.The major features of Johannes Clauberg's hermeneutics are examined in this paper, as they appear in the very structure of one of his major works, the Logica Vetus et Nova, and particularly in the pattern of analysis provided by this work when it comes to interpret an " obscure sentence ". Clauberg looks for the roots of ambiguity and obscurity rather in the words themselves than in their syntactic combinations; because - that's the conclusion we intend to draw - of his conception of the relation between language and thought. For Clauberg, language and thought are too identical in their structures for a major discrepancy to occur between them.

  17. Tuberculose multifocale chez les immunocompétents

    Science.gov (United States)

    Rezgui, Amel; Fredj, Fatma Ben; Mzabi, Anis; Karmani, Monia; Laouani, Chadia

    2016-01-01

    La tuberculose multifocale est définie par la l'atteinte d'au moins deux sites extra-pulmonaires associée ou non à une atteinte pulmonaire. On se propose d’étudier les différentes caractéristiques cliniques et évolutives de la tuberculose multifocale à travers une étude rétrospective de 10 cas. Parmi 41 cas de tuberculose colligés entre 1999 et 2013. Dix patients avaient une tuberculose multifocale, soit 24% des patients. Il s'agissait de 9 femmes et 1 homme d’âge moyen à 50 ans (30-68 ans). Nos patients étaient tous correctement vaccinés par le BCG. Un bilan à la recherche d'une éventuelle immunodépression fait pour tous les patients était négatif. Il s'agissait d'une tuberculose ganglionnaire dans 7 cas, digestive dans 3 cas, péricardique dans 2 cas, ostéo-articulaire dans 2 cas, cérébrale dans 1 cas, urinaire dans 2 cas, uro-génitale dans 4 cas, surrénalienne dans 1 cas, cutanée dans 1 cas et musculaire dans 1 cas. Tous nos patients ont bénéficié d'un traitement antituberculeux pour une durée moyenne de 10 mois avec bonne évolution. La tuberculose multifocale est une des maladies à diagnostic difficile. Elle peut toucher les immunocompétents mais son pronostic est souvent bon. Un traitement anti-tuberculeux doit être instauré le plus rapidement possible pour éviter les séquelles. PMID:27583077

  18. Les modalités du temps chez Benjamin Franklin

    OpenAIRE

    Elise Marienstras

    2010-01-01

    La renommée multiséculaire de Benjamin Franklin tient surtout à sa qualité d'homme des Lumières. Cet article s'intéresse à l'extrême complexité de sa pensée sur le temps comme concept, comme mode de vie, comme outil pour s'enrichir, et comme vision générale du progrès du genre humain.The long-lasting fame of Benjamin Franklin rests principally on his characteristics as a scientist and a philosopher of the Enlightenment. This article raises the question of Franklin's conception of time and exa...

  19. Les modalités du temps chez Benjamin Franklin

    Directory of Open Access Journals (Sweden)

    Elise Marienstras

    2010-01-01

    Full Text Available La renommée multiséculaire de Benjamin Franklin tient surtout à sa qualité d'homme des Lumières. Cet article s'intéresse à l'extrême complexité de sa pensée sur le temps comme concept, comme mode de vie, comme outil pour s'enrichir, et comme vision générale du progrès du genre humain.The long-lasting fame of Benjamin Franklin rests principally on his characteristics as a scientist and a philosopher of the Enlightenment. This article raises the question of Franklin's conception of time and examines his numerous uses of « time » as a concept, as a way of living, as a means to obtain wealth, as a general vision of the progress of mankind.

  20. ONTOLOGIE ET MÉTAPHYSIQUE CHEZ LES GRECS. PLATON

    Directory of Open Access Journals (Sweden)

    GHEORGHE VLĂDUŢESCU

    2011-11-01

    Full Text Available The aim of this essay is to highlighting the issue of being(nessand of modality in Plato’s philosophy under the Socratic influence for the ontological design in its metaphysical significance. I follow some cardinal concepts, like: eidos and idéa within the development of the doctrine of ideas, trying to stress the importance of a holistic reading in the dynamic unity of Plato’s Dialogues, to enlightening the central category of being(ness.

  1. Les brulures electriques chez les voleurs de cuivre

    Science.gov (United States)

    Belmir, R.; Fejjal, N.; Achbouk, H.; El Mazouz, S.; Gharib, N.; Abassi, A.; Belmahi, A.

    2011-01-01

    Summary Les vols de biens fabriqués avec le cuivre semblent en hausse depuis un certain temps du fait de son prix élevé de revente, ce qui est à l’origine d’une augmentation du nombre d’accidents électriques par haut voltage (AEHV) qui sont graves du fait des brûlures profondes qu’elles provoquent le long des axes vasculo-nerveux. Les Auteurs rapportent une série de neuf cas d’AEHV traités au service de chirurgie plastique et de brûlés de l’Hôpital Ibn Sina de Rabat, Maroc, à travers laquelle ils étudient les caractéristiques épidémiologiques, cliniques et thérapeutiques. La population intéressée était jeune et active. Les brûlures étaient secondaires à un contact avec des câbles à haute tension lors de tentatives de vol par arrachement de conducteurs en cuivre dans les transformateurs dans 67% des cas, et lors de tentatives de coupure de caténaires alimentant les trains électriques sur le réseau ferroviaire dans 33% des cas. Le traitement des lésions électrothermiques a nécessité des interventions itératives avec amputation et désarticulation des segments de membres nécrosés dans 66% des cas, dont les suites étaient marquées par des séquelles fonctionnelles invalidantes. La prévention de ce type d’AEHV reste fondamentale. PMID:22262961

  2. Pathologies : La rétention placentaire chez la vache.

    OpenAIRE

    Hanzen, Christian

    2015-01-01

    Objectif général : Au travers de rappels anatomiques et pathogéniques, le chapitre a pour but de faire comprendre pourquoi cette pathologie concerne davantage l’espèce bovine. L’accent sera également mis sur le caractère multifactoriel de la pathologie ce qui implique sur le plan thérapeutique la mise en place d’une stratégie individuelle mais également de troupeau

  3. Discours et stratégies de persuasion chez Keynes

    OpenAIRE

    Gilles Dostaler

    2002-01-01

    John Maynard Keynes a élaboré une nouvelle analyse économique qui a servi a rationaliser les politiques interventionnistes associées à son nom. Mais avant d'être un théoricien de l'économie, Keynes se définissait lui-même comme un 'publiciste', soucieux de convaincre ses contemporains de l'urgente nécessité de procéder à des transformations essentielles pour éviter l'écroulement de la civilisation. Pour y arriver, il se sert avant tout du langage et use avec une grande habileté de tous les ar...

  4. Peste émotionnelle et imaginaire social chez Wilhelm Reich

    Directory of Open Access Journals (Sweden)

    Georges Bertin

    2003-12-01

    Full Text Available Il est pour nous frappant, presque au sens premier, de constater aujourd'hui que les analyses sociologiques posées par Wilhelm Reich voici 70 ans sont à nouveau d'une extrême actualité. Alors qu'une des grandes voix de l'analyse critique, celle de Castoriadis, bien éloignée des sophismes actuels de nouveaux philosophes s'évertuant surtout à accéder aux prébendes publiques et éditoriales, s'est éteinte depuis maintenant six ans, alors que les politiciens s'évertuent, sur les scènes de la Société du Spectacle, à faire assaut des procédés de communication les plus dérisoires pour masquer leur absence de pensée politique, jamais notre société post moderne n'a en effet été aussi proche de cette crise des significations imaginaires sociales que Reich nommait déjà, dans les années 30, peste émotionnelle.

  5. Effets du fluor et du phosphogypse chez les organismes marins

    OpenAIRE

    Martin, J. L.; Le Guellec, Anne-marie; Cosson, R

    1982-01-01

    Dans le cadre général des recherches visant à déterminer l'action des effluents industriels et plus précisément du fluor dans le cas de cette étude, le programme dont les résultats sont présentés avait pour but de déterminer les effets de cet élément sur les organismes marins. Trois aspects essentiels ont été envisagés : - Effets létaux du fluor ; - effets du fluor sur certaines fonctions éthologiques ; - bio-accumulation de l'élément par les organismes marins.

  6. L’alphabet chez les enfants sourds et malentendants

    OpenAIRE

    Hamm, Mélanie

    2014-01-01

    International audience Malgré les progrès des sciences et des technologies éducatives, une grande méconnaissance et de nombreux préjugés demeurent quant aux aptitudes à la lecture et à l’écriture des enfants sourds et malentendants. Pour quelqu’un qui naît sourd, il n’y a pas de parole antérieure au sens du langage articulé. Dès lors, comment apprendre à lire à celui qui n’entend pas ou mal ?

  7. Les plantes exotiques odorantes chez Batiouchkov et Pouchkine

    OpenAIRE

    Pilshchikov, Igor

    2013-01-01

    Le présent article suit le parcours de plusieurs noms de plantes qui fonctionnent comme autant d’indices de l’exotique – antique, biblique ou nordique – dans la poésie russe des premières décennies du XIXe siècle. Ainsi est observée la richesse combinatoire d’un motif qui peut donner lieu à un cliché stylistique autant qu’à un usage lyrique ou ironique et auto-réflexif.

  8. Le bilinguisme chez les enfants: bibliographie (Child Bilingualism: a Bibliography)

    Science.gov (United States)

    Lundgren-Turiaf, Simone

    1976-01-01

    This bibliography on child bilingualism in France contains 82 entries distributed among three sections: 1) psychosociologic and cultural aspects of migrant worker children, learning conditions; 2) bilingual-bicultural education, experiences and methodological problems; and 3) bilingualism in the countries of origin. (Text is in French.) (TL)

  9. Antiquaires et antiquités chez Gillray et Daumier

    OpenAIRE

    Contogouris, Ersy

    2014-01-01

    Dans La Parade d’Honoré Daumier [Fig.1], cinq saltimbanques tentent ans par tous les moyens d’attirer l’attention du public : déguisés, ils s’interpellent pellent et gesticulent, l’un pointe vers la scène burlesque d’un crocodile ans par tous les moyens d’attirer l’attention du public : déguisés, ils s’interpellent et gesticulent, l’un pointe vers la scène burlesque d’un crocodile pourchassant sa prochaine victime, tandis que l’autre fait entrevoir ce qu’il y a derrière le rideau pour éveille...

  10. Utilisation du transport en commun chez les immigrants

    OpenAIRE

    Heisz, Andrew; Schellenberg, Grant

    2004-01-01

    Dans cet article, on examine, a l'aide des donnees tirees des recensements de la population de 1996 et de 2001, la probabilite que les immigrants et les personnes nees au Canada utilisent le transport en commun. On discute egalement des repercussions sur les services de transport en commun.

  11. Possibilité et existentiabilité chez Leibniz

    OpenAIRE

    Jeangène Vilmer, Jean-Baptiste

    2006-01-01

    International audience; It is well-known that Leibniz's ontology as it were traces the shortest path from possibility to existence. The fact is measured less that this line is covered by stages, the first of which is assuredly the existentiability of possibles. This article first examines Leibniz's conception of possibility by means of five definitions. It then analyses the nature and role of this existentiability in its relations to possibility, on the one hand, and existence, on the other, ...

  12. Détermination du besoin en isoleucine chez le porcelet

    OpenAIRE

    Gloaguen, Mathieu; Le Floc'h, Nathalie; PRIMOT, Yvan; Corrent, Etienne; Van Milgen, Jacob

    2012-01-01

    The branched‐chain amino acids (BCAA: valine, leucine, isoleucine) are among the next‐limiting amino acids for growth in piglets after Lys, Thr, Met+Cys and Trp. To formulate low crude protein diets, a clear understanding of the BCAA requirement (e.g. Ile) is required. Most studies dealing with the Ile requirement use blood cells as a protein source, which has a very low Ile content and high or very high Leu and Val contents. However, the BCAA share the first two steps of their catabolism and...

  13. Chez Peter Higgs, père du fameux boson

    CERN Multimedia

    Dessibourg, Olivier

    2008-01-01

    At CERN, near Geneva, the LHC accelerator should start in 2008 for a fabulous search: find the "Higgs boson", a postulated particle in 1964, and who should revolutionize physics. An exclusive meeting in Edimburg with its "inventor", a modest Scottish physicist. (4 pages)

  14. Chez nous: mon village (At Our House: My Village).

    Science.gov (United States)

    Dube, Normand

    This elementary French reader was designed for use in a bilingual program. It contains reading selections about life in Madawaska, Maine, illustrated vocabulary lists, and discussion questions. Also included are the words and music for two short songs and four phonetic drills. (PMP)

  15. Male breast cancer: 22 case reports at the National Hospital of Niamey- Niger (West Africa Le cancer du sein chez l'homme: à propos de 22 cas a l'Hôpital National de Niamey- Niger (Afrique de l'Ouest

    Directory of Open Access Journals (Sweden)

    Nouhou Hassane

    2009-11-01

    Full Text Available BACKGROUND: Male breast cancer (MBC is rare. The objective of the study is to report clinicopathological characteristics, treatment patterns, and outcomes of MBC. METHODS: This study, which includes two parts (retrospective and prospective, focused on all hospitalized male patients with breast cancer during 17 years (1992–2008 with histological confirmation. RESULTS: The series included 22 patients. The mean age was 52.8 years (range: 28–80 years. MBC represented 5.7% of all breast cancers. Most patients had an advanced disease with skin ulceration and inflammation T3 (31.9% and T4 (59.1%. The majority of patients came from rural areas (63.6%. The duration of signs ranged from 1 to 7 years. Histology found infiltrating ductal carcinoma in 14 cases (63.6%, sarcoma in 3 cases (13.6%, papillary carcinoma in 2 cases (9%, and lobular carcinoma, medullar carcinoma, and mucinous carcinoma in 4.6% each of the others cases. The treatment had consisted of a radical mastectomy (Halsted or Patey in 19 cases (86.4% with axillary clearance and incomplete resection in 3 cases (13.6%. In the retrospective study follow-up of 14 patients, we lost sight of 13 patients 6 months after surgery. In the prospective study of 8 patients 10 to 36 months after mastectomy, 4 patients were deceased (50%, 4 were alive with 1 case having a local recurrence and pulmonary metastasis. CONCLUSION: The advanced clinical forms of MBC are most frequent with skin ulceration and nodal enlargement. The absence of radiotherapy and the low access of chemotherapy limited the treatment to radical mastectomy (Halsted in the majority of cases. OBJECTIF : Le cancer du sein chez l’homme (CSH est une affection rare .Le but de cette étude est de déterminer les caractéristiques clinicopathologiques, les résultats du traitement et l’évolution du CSH. Méthodologie : Il s’agit d’étude comportant 2 volets (rétrospectif et prospectif. Etaient inclus tous les patients de sexe

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

    OpenAIRE

    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.

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

    NARCIS (Netherlands)

    Ozgur, E.; Afsar, N.; Vrije, de G.J.; Yucel, M.; Gunduz, U.; Claassen, P.A.M.; Eroglu, I.

    2010-01-01

    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

  18. A simple method for encapsulating single cells in alginate microspheres allows for direct PCR and whole genome amplification.

    Directory of Open Access Journals (Sweden)

    Saharnaz Bigdeli

    Full Text Available Microdroplets are an effective platform for segregating individual cells and amplifying DNA. However, a key challenge is to recover the contents of individual droplets for downstream analysis. This paper offers a method for embedding cells in alginate microspheres and performing multiple serial operations on the isolated cells. Rhodobacter sphaeroides cells were diluted in alginate polymer and sprayed into microdroplets using a fingertip aerosol sprayer. The encapsulated cells were lysed and subjected either to conventional PCR, or whole genome amplification using either multiple displacement amplification (MDA or a two-step PCR protocol. Microscopic examination after PCR showed that the lumen of the occupied microspheres contained fluorescently stained DNA product, but multiple displacement amplification with phi29 produced only a small number of polymerase colonies. The 2-step WGA protocol was successful in generating fluorescent material, and quantitative PCR from DNA extracted from aliquots of microspheres suggested that the copy number inside the microspheres was amplified up to 3 orders of magnitude. Microspheres containing fluorescent material were sorted by a dilution series and screened with a fluorescent plate reader to identify single microspheres. The DNA was extracted from individual isolates, re-amplified with full-length sequencing adapters, and then a single isolate was sequenced using the Illumina MiSeq platform. After filtering the reads, the only sequences that collectively matched a genome in the NCBI nucleotide database belonged to R. sphaeroides. This demonstrated that sequencing-ready DNA could be generated from the contents of a single microsphere without culturing. However, the 2-step WGA strategy showed limitations in terms of low genome coverage and an uneven frequency distribution of reads across the genome. This paper offers a simple method for embedding cells in alginate microspheres and performing PCR on isolated

  19. Studies of Structure and Dynamics of Light Harvesting Complex 1 of R. Sphaeroides by Solid State NMR

    Energy Technology Data Exchange (ETDEWEB)

    McDermott, Ann E [Columbia Univ., New York, NY (United States)

    2014-11-14

    Studies of the structure and dynamics of a light harvesting complex from photosynthetic bacteria are described. Using Nuclear Magnetic Resonance methods, we explored the idea that optical properties are modulated via a conformational switch in the BChl chromophores, in a way that provides benefits for the efficiency of energy conversion.

  20. Production of bioplastics and hydrogen gas by photosynthetic microorganisms

    Science.gov (United States)

    Yasuo, Asada; Masato, Miyake; Jun, Miyake

    1998-03-01

    Our efforts have been aimed at the technological basis of photosynthetic-microbial production of materials and an energy carrier. We report here accumulation of poly-(3-hydroxybutyrate) (PHB), a raw material of biodegradable plastics and for production of hydrogen gas, and a renewable energy carrier by photosynthetic microorganisms (tentatively defined as cyanobacteria plus photosynthetic bateria, in this report). A thermophilic cyanobacterium, Synechococcus sp. MA19 that accumulates PHB at more than 20% of cell dry wt under nitrogen-starved conditions was isolated and microbiologically identified. The mechanism of PHB accumulation was studied. A mesophilic Synechococcus PCC7942 was transformed with the genes encoding PHB-synthesizing enzymes from Alcaligenes eutrophus. The transformant accumulated PHB under nitrogen-starved conditions. The optimal conditions for PHB accumulation by a photosynthetic bacterium grown on acetate were studied. Hydrogen production by photosynthetic microorganisms was studied. Cyanobacteria can produce hydrogen gas by nitrogenase or hydrogenase. Hydrogen production mediated by native hydrogenase in cyanobacteria was revealed to be in the dark anaerobic degradation of intracellular glycogen. A new system for light-dependent hydrogen production was targeted. In vitro and in vivo coupling of cyanobacterial ferredoxin with a heterologous hydrogenase was shown to produce hydrogen under light conditions. A trial for genetic trasformation of Synechococcus PCC7942 with the hydrogenase gene from Clostridium pasteurianum is going on. The strong hydrogen producers among photosynthetic bacteria were isolated and characterized. Co-culture of Rhodobacter and Clostriumdium was applied to produce hydrogen from glucose. Conversely in the case of cyanobacteria, genetic regulation of photosynthetic proteins was intended to improve conversion efficiency in hydrogen production by the photosynthetic bacterium, Rhodobacter sphaeroides RV. A mutant acquired by

  1. La φιλοστοργία chez Fronton, une vertu sans équivalent latin ? Is φιλοστοργία in Fronto a virtue without Latin equivalent? La φιλοστοργία di Frontone: una virtù senza esatto equivalente latino?

    Directory of Open Access Journals (Sweden)

    Sophie Aubert

    2011-07-01

    Full Text Available Oscillant entre deux acceptions – l’amour d’un être vivant pour sa progéniture ou, chez les auteurs chrétiens, l’affection vive - la philostorgia ne semble pas dotée d’un équivalent latin exact : dans leur correspondance, Cicéron puis Fronton emploient en effet ce terme grec sans le traduire. L’Arpinate en réélabore le sens, grâce à l’apport du stoïcisme, pour le rattacher à l’amour du genre humain (philanthrôpia par le biais de la théorie de l’oikéiôsis (ou « appropriation », démontrant ainsi que l’affection des parents pour leurs enfants est ancrée dans la nature et que l’aptitude de l’homme à vivre en société, par conséquent, est elle aussi naturelle, selon un raisonnement exposé au livre III du De Finibus, ouvrage contemporain du premier emploi du mot philostorgia dans les lettres de Cicéron. Quant au maître de rhétorique de Marc Aurèle, il souligne son incapacité à traduire ce mot tout en l’associant à la franchise dans l’affection ainsi qu’à une intimité quasi familiale et en déplorant que cette vertu fût absente du cœur des Romains, plus précisément sans doute des courtisans de son élève impérial. Or si ce dernier, dans ses Pensées, exprime le même regret face à la dureté et à l’hypocrisie de son entourage, il réinterprète la philostorgia à la lumière de la philosophie du Portique puisqu’il la rattache non seulement à la bonté (eumeneia, l’une des subdivisions de l’émotion positive qu’est le désir rationnel (ou boulêsis, mais aussi à la philanthrôpia, et qu’il bannit l’ironie au profit d’une sincérité indispensable à l’affection, faisant ici écho au portrait du sage stoïcien tel que le dresse Stobée. Ainsi Marc Aurèle tire-t-il profit à la fois des leçons de son professeur et de l’enseignement des philosophes du Portique.Oscillating between two meanings - the love of a living being for its offspring, or among Christian

  2. Le tubage gastrique chez les poissons : mise au point d'un équipement et test chez le chabot Cottus gobio L.

    OpenAIRE

    GAUDIN P.; Martin, E.; CAILLERE L.

    1981-01-01

    Un système de vidange stomacale a été mis au point dans le but de préciser le régime alimentaire d'une petite population de chabots (Cottus gobio L.). Le matériel et les principes d'utilisation sont décrits. La méthode a été testée au laboratoire et sur le terrain. L'expérimentation réalisée au laboratoire montre que : 1 — l'efficacité de la vidange stomacale est très satisfaisante (98,2 % ) , 2 — le taux de réalimentation est très élevé 24 heures après la vidange, 3 — la survie, un mois aprè...

  3. Different biochemical mechanisms ensure network-wide balancing of reducing equivalents in microbial metabolism.

    Science.gov (United States)

    Fuhrer, Tobias; Sauer, Uwe

    2009-04-01

    To sustain growth, the catabolic formation of the redox equivalent NADPH must be balanced with the anabolic demand. The mechanisms that ensure such network-wide balancing, however, are presently not understood. Based on 13C-detected intracellular fluxes, metabolite concentrations, and cofactor specificities for all relevant central metabolic enzymes, we have quantified catabolic NADPH production in Agrobacterium tumefaciens, Bacillus subtilis, Escherichia coli, Paracoccus versutus, Pseudomonas fluorescens, Rhodobacter sphaeroides, Sinorhizobium meliloti, and Zymomonas mobilis. For six species, the estimated NADPH production from glucose catabolism exceeded the requirements for biomass synthesis. Exceptions were P. fluorescens, with balanced rates, and E. coli, with insufficient catabolic production, in which about one-third of the NADPH is supplied via the membrane-bound transhydrogenase PntAB. P. versutus and B. subtilis were the only species that appear to rely on transhydrogenases for balancing NADPH overproduction during growth on glucose. In the other four species, the main but not exclusive redox-balancing mechanism appears to be the dual cofactor specificities of several catabolic enzymes and/or the existence of isoenzymes with distinct cofactor specificities, in particular glucose 6-phosphate dehydrogenase. An unexpected key finding for all species, except E. coli and B. subtilis, was the lack of cofactor specificity in the oxidative pentose phosphate pathway, which contrasts with the textbook view of the pentose phosphate pathway dehydrogenases as being NADP+ dependent.

  4. Kinetic study approach of remazol black-B use for the development of two-stage anoxic-oxic reactor for decolorization/biodegradation of azo dyes by activated bacterial consortium.

    Science.gov (United States)

    Dafale, Nishant; Wate, Satish; Meshram, Sudhir; Nandy, Tapas

    2008-11-30

    The laboratory-isolated strains Pseudomonas aeruginosa, Rhodobacter sphaeroides, Proteus mirabilis, Bacillus circulance, NAD 1 and NAD 6 were observed to be predominant in the bacterial consortium responsible for effective decolorization of the azo dyes. The kinetic characteristics of azo dye decolorization by bacterial consortium were determined quantitatively using reactive vinyl sulfonated diazo dye, remazol black-B (RB-B) as a model substrate. Effects of substrate (RB-B) concentration as well as different substrates (azo dyes), environmental parameters (temperature and pH), glucose and other electron donor/co-substrate on the rate of decolorization were investigated to reveal the key factor that determines the performance of dye decolorization. The activation energy (E(a)) and frequency factor (K(0)) based on the Arrhenius equation was calculated as 11.67 kcal mol(-1) and 1.57 x 10(7)mg lg MLSS(-1)h(-1), respectively. The Double-reciprocal or Lineweaver-Burk plot was used to evaluate V(max), 15.97 h(-1) and K(m), 85.66 mg l(-1). The two-stage anoxic-oxic reactor system has proved to be successful in achieving significant decolorization and degradation of azo dyes by specific developed bacterial consortium with a removal of 84% color and 80% COD for real textile effluents vis-à-vis >or=90% color and COD removal for synthetic dye solution.

  5. Self-assembling photosynthetic reaction centers on electrodes for current generation.

    Science.gov (United States)

    Nakamura, C; Hasegawa, M; Yasuda, Y; Miyake, J

    2000-01-01

    Photosynthetic reaction centers (RCs) made from photosynthetic organisms can be used in solar batteries because their molecules cause light-induced charge separation. We present a simple immobilization system of the intact RCs from Rhodobacter sphaeroides on an electrode that uses nickel ligand binding by the hexameric histidine tag on H subunit (HHisRC). The binding constant of HHisRC to the nickel-nitrilotriacetic acid (Ni-NTA) chip measured with a surface plasmon resonance instrument was 1.6 x 10(8) M-1. HHisRCs were immobilized on an indium tin oxide electrode overlaid with an Ni-NTA gold substrate. The photoinduced displacement current of this electrode was measured to estimate the orientation of HHisRC on the electrode, and the detachability of HHisRC from the electrode was determined by using an imidazole solution wash. The direction of the flash-light-induced displacement current suggested that the H subunit side of the immobilized HHisRC faced the surface of the electrode. The photoinduced current disappeared after the electrode was washed in the imidazole solution. This simple immobilization and detachment of HHisRC to the electrode might be useful for making a reproducible photocurrent device. PMID:10849806

  6. RpoH2 sigma factor controls the photooxidative stress response in a non-photosynthetic rhizobacterium, Azospirillum brasilense Sp7.

    Science.gov (United States)

    Kumar, Santosh; Rai, Ashutosh Kumar; Mishra, Mukti Nath; Shukla, Mansi; Singh, Pradhyumna Kumar; Tripathi, Anil Kumar

    2012-12-01

    Bacteria belonging to the Alphaproteobacteria normally harbour multiple copies of the heat shock sigma factor (known as σ(32), σ(H) or RpoH). Azospirillum brasilense, a non-photosynthetic rhizobacterium, harbours five copies of rpoH genes, one of which is an rpoH2 homologue. The genes around the rpoH2 locus in A. brasilense show synteny with that found in rhizobia. The rpoH2 of A. brasilense was able to complement the temperature-sensitive phenotype of the Escherichia coli rpoH mutant. Inactivation of rpoH2 in A. brasilense results in increased sensitivity to methylene blue and to triphenyl tetrazolium chloride (TTC). Exposure of A. brasilense to TTC and the singlet oxygen-generating agent methylene blue induced several-fold higher expression of rpoH2. Comparison of the proteome of A. brasilense with its rpoH2 deletion mutant and with an A. brasilense strain overexpressing rpoH2 revealed chaperone GroEL, elongation factors (Ef-Tu and EF-G), peptidyl prolyl isomerase, and peptide methionine sulfoxide reductase as the major proteins whose expression was controlled by RpoH2. Here, we show that the RpoH2 sigma factor-controlled photooxidative stress response in A. brasilense is similar to that in the photosynthetic bacterium Rhodobacter sphaeroides, but that RpoH2 is not involved in the detoxification of methylglyoxal in A. brasilense.

  7. The Structure of L-Tyrosine 2,3-Aminomutase frmo the C-1027 Enediyne Antitumor Antibiotic Biosynthetic Pathway

    Energy Technology Data Exchange (ETDEWEB)

    Christianson,C.; Montavon, T.; Van Lanen, S.; Shen, B.; Bruner, S.

    2007-01-01

    The SgcC4 L-tyrosine 2,3-aminomutase (SgTAM) catalyzes the formation of (S)-{beta}-tyrosine in the biosynthetic pathway of the enediyne antitumor antibiotic C-1027. SgTAM is homologous to the histidine ammonia lyase family of enzymes whose activity is dependent on the methylideneimidazole-5-one (MIO) cofactor. Unlike the lyase enzymes, SgTAM catalyzes additional chemical transformations resulting in an overall stereospecific 1,2-amino shift in the substrate L-tyrosine to generate (S)-{beta}-tyrosine. Previously, we provided kinetic, spectroscopic, and mutagenesis data supporting the presence of MIO in the active site of SgTAM [Christenson, S. D.; Wu, W.; Spies, A.; Shen, B.; and Toney, M. D. (2003) Biochemistry 42, 12708-12718]. Here we report the first X-ray crystal structure of an MIO-containing aminomutase, SgTAM, and confirm the structural homology of SgTAM to ammonia lyases. Comparison of the structure of SgTAM to the L-tyrosine ammonia lyase from Rhodobacter sphaeroides provides insight into the structural basis for aminomutase activity. The results show that SgTAM has a closed active site well suited to retain ammonia and minimize the formation of lyase elimination products. The amino acid determinants for substrate recognition and catalysis can be predicted from the structure, setting the framework for detailed mechanistic investigations.

  8. The structure of L-tyrosine 2,3-aminomutase from the C-1027 enediyne antitumor antibiotic biosynthetic pathway.

    Science.gov (United States)

    Christianson, Carl V; Montavon, Timothy J; Van Lanen, Steven G; Shen, Ben; Bruner, Steven D

    2007-06-19

    The SgcC4 l-tyrosine 2,3-aminomutase (SgTAM) catalyzes the formation of (S)-beta-tyrosine in the biosynthetic pathway of the enediyne antitumor antibiotic C-1027. SgTAM is homologous to the histidine ammonia lyase family of enzymes whose activity is dependent on the methylideneimidazole-5-one (MIO) cofactor. Unlike the lyase enzymes, SgTAM catalyzes additional chemical transformations resulting in an overall stereospecific 1,2-amino shift in the substrate l-tyrosine to generate (S)-beta-tyrosine. Previously, we provided kinetic, spectroscopic, and mutagenesis data supporting the presence of MIO in the active site of SgTAM [Christenson, S. D.; Wu, W.; Spies, A.; Shen, B.; and Toney, M. D. (2003) Biochemistry 42, 12708-12718]. Here we report the first X-ray crystal structure of an MIO-containing aminomutase, SgTAM, and confirm the structural homology of SgTAM to ammonia lyases. Comparison of the structure of SgTAM to the l-tyrosine ammonia lyase from Rhodobacter sphaeroides provides insight into the structural basis for aminomutase activity. The results show that SgTAM has a closed active site well suited to retain ammonia and minimize the formation of lyase elimination products. The amino acid determinants for substrate recognition and catalysis can be predicted from the structure, setting the framework for detailed mechanistic investigations. PMID:17516659

  9. Structure of bacterial cytoplasmic chemoreceptor arrays and implications for chemotactic signaling.

    Science.gov (United States)

    Briegel, Ariane; Ladinsky, Mark S; Oikonomou, Catherine; Jones, Christopher W; Harris, Michael J; Fowler, Daniel J; Chang, Yi-Wei; Thompson, Lynmarie K; Armitage, Judith P; Jensen, Grant J

    2014-01-01

    Most motile bacteria sense and respond to their environment through a transmembrane chemoreceptor array whose structure and function have been well-studied, but many species also contain an additional cluster of chemoreceptors in their cytoplasm. Although the cytoplasmic cluster is essential for normal chemotaxis in some organisms, its structure and function remain unknown. Here we use electron cryotomography to image the cytoplasmic chemoreceptor cluster in Rhodobacter sphaeroides and Vibrio cholerae. We show that just like transmembrane arrays, cytoplasmic clusters contain trimers-of-receptor-dimers organized in 12-nm hexagonal arrays. In contrast to transmembrane arrays, however, cytoplasmic clusters comprise two CheA/CheW baseplates sandwiching two opposed receptor arrays. We further show that cytoplasmic fragments of normally transmembrane E. coli chemoreceptors form similar sandwiched structures in the presence of molecular crowding agents. Together these results suggest that the 12-nm hexagonal architecture is fundamentally important and that sandwiching and crowding can replace the stabilizing effect of the membrane. DOI: http://dx.doi.org/10.7554/eLife.02151.001.

  10. Overall energy conversion efficiency of a photosynthetic vesicle.

    Science.gov (United States)

    Sener, Melih; Strumpfer, Johan; Singharoy, Abhishek; Hunter, C Neil; Schulten, Klaus

    2016-08-26

    The chromatophore of purple bacteria is an intracellular spherical vesicle that exists in numerous copies in the cell and that efficiently converts sunlight into ATP synthesis, operating typically under low light conditions. Building on an atomic-level structural model of a low-light-adapted chromatophore vesicle from Rhodobacter sphaeroides, we investigate the cooperation between more than a hundred protein complexes in the vesicle. The steady-state ATP production rate as a function of incident light intensity is determined after identifying quinol turnover at the cytochrome bc1 complex (cytb⁢c1) as rate limiting and assuming that the quinone/quinol pool of about 900 molecules acts in a quasi-stationary state. For an illumination condition equivalent to 1% of full sunlight, the vesicle exhibits an ATP production rate of 82 ATP molecules/s. The energy conversion efficiency of ATP synthesis at illuminations corresponding to 1%-5% of full sunlight is calculated to be 0.12-0.04, respectively. The vesicle stoichiometry, evolutionarily adapted to the low light intensities in the habitat of purple bacteria, is suboptimal for steady-state ATP turnover for the benefit of protection against over-illumination.

  11. Valencene synthase from the heartwood of Nootka cypress (Callitropsis nootkatensis) for biotechnological production of valencene.

    Science.gov (United States)

    Beekwilder, Jules; van Houwelingen, Adèle; Cankar, Katarina; van Dijk, Aalt D J; de Jong, René M; Stoopen, Geert; Bouwmeester, Harro; Achkar, Jihane; Sonke, Theo; Bosch, Dirk

    2014-02-01

    Nootkatone is one of the major terpenes in the heartwood of the Nootka cypress Callitropsis nootkatensis. It is an oxidized sesquiterpene, which has been postulated to be derived from valencene. Both valencene and nootkatone are used for flavouring citrus beverages and are considered among the most valuable terpenes used at commercial scale. Functional evaluation of putative terpene synthase genes sourced by large-scale EST sequencing from Nootka cypress wood revealed a valencene synthase gene (CnVS). CnVS expression in different tissues from the tree correlates well with nootkatone content, suggesting that CnVS represents the first dedicated gene in the nootkatone biosynthetic pathway in C. nootkatensis The gene belongs to the gymnosperm-specific TPS-d subfamily of terpenes synthases and its protein sequence has low similarity to known citrus valencene synthases. In vitro, CnVS displays high robustness under different pH and temperature regimes, potentially beneficial properties for application in different host and physiological conditions. Biotechnological production of sesquiterpenes has been shown to be feasible, but productivity of microbial strains expressing valencene synthase from Citrus is low, indicating that optimization of valencene synthase activity is needed. Indeed, expression of CnVS in Saccharomyces cerevisiae indicated potential for higher yields. In an optimized Rhodobacter sphaeroides strain, expression of CnVS increased valencene yields 14-fold to 352 mg/L, bringing production to levels with industrial potential. PMID:24112147

  12. Carotenoid charge transfer states and their role in energy transfer processes in LH1-RC complexes from aerobic anoxygenic phototrophs.

    Science.gov (United States)

    Šlouf, Václav; Fuciman, Marcel; Dulebo, Alexander; Kaftan, David; Koblížek, Michal; Frank, Harry A; Polívka, Tomáš

    2013-09-26

    Light-harvesting complexes ensure necessary flow of excitation energy into photosynthetic reaction centers. In the present work, transient absorption measurements were performed on LH1-RC complexes isolated from two aerobic anoxygenic phototrophs (AAPs), Roseobacter sp. COL2P containing the carotenoid spheroidenone, and Erythrobacter sp. NAP1 which contains the carotenoids zeaxanthin and bacteriorubixanthinal. We show that the spectroscopic data from the LH1-RC complex of Roseobacter sp. COL2P are very similar to those previously reported for Rhodobacter sphaeroides, including the transient absorption spectrum originating from the intramolecular charge-transfer (ICT) state of spheroidenone. Although the ICT state is also populated in LH1-RC complexes of Erythrobacter sp. NAP1, its appearance is probably related to the polarity of the bacteriorubixanthinal environment rather than to the specific configuration of the carotenoid, which we hypothesize is responsible for populating the ICT state of spheroidenone in LH1-RC of Roseobacter sp. COL2P. The population of the ICT state enables efficient S1/ICT-to-bacteriochlorophyll (BChl) energy transfer which would otherwise be largely inhibited for spheroidenone and bacteriorubixanthinal due to their low energy S1 states. In addition, the triplet states of these carotenoids appear well-tuned for efficient quenching of singlet oxygen or BChl-a triplets, which is of vital importance for oxygen-dependent organisms such as AAPs. PMID:23130956

  13. The role of pH control on biohydrogen production by single stage hybrid dark- and photo-fermentation.

    Science.gov (United States)

    Zagrodnik, R; Laniecki, M

    2015-10-01

    The role of pH control on biohydrogen production by co-culture of dark-fermentative Clostridium acetobutylicum and photofermentative Rhodobacter sphaeroides was studied. Single stage dark fermentation, photofermentation and hybrid co-culture systems were studied at different values of controlled and uncontrolled pH. Increasing pH during dark fermentation resulted in lower hydrogen production rate (HPR) and longer lag time for both controlled and uncontrolled conditions. However, it only slightly affected cumulative H2 volume. Results have shown that pH control at pH 7.5 increased photofermentative hydrogen production from 0.966 to 2.502 L H2/L(medium) when compared to uncontrolled process. Fixed pH value has proven to be an important control strategy also for the hybrid process and resulted in obtaining balanced co-culture of dark and photofermentative bacteria. Control of pH at 7.0 was found optimum for bacteria cooperation in the co-culture what resulted in obtaining 2.533 L H2/L(medium) and H2 yield of 6.22 mol H2/mol glucose. PMID:26196419

  14. Laterally Mobile, Functionalized Self-Assembled Monolayers at the Fluorous−Aqueous Interface in a Plug-Based Microfluidic System: Characterization and Testing with Membrane Protein Crystallization

    Energy Technology Data Exchange (ETDEWEB)

    Kreutz, Jason E.; Li, Liang; Roach, L. Spencer; Hatakeyama, Takuji; Ismagilov, Rustem F.; (UC)

    2009-11-04

    This paper describes a method to generate functionalizable, mobile self-assembled monolayers (SAMs) in plug-based microfluidics. Control of interfaces is advancing studies of biological interfaces, heterogeneous reactions, and nanotechnology. SAMs have been useful for such studies, but they are not laterally mobile. Lipid-based methods, though mobile, are not easily amenable to setting up the hundreds of experiments necessary for crystallization screening. Here we demonstrate a method, complementary to current SAM and lipid methods, for rapidly generating mobile, functionalized SAMs. This method relies on plugs, droplets surrounded by a fluorous carrier fluid, to rapidly explore chemical space. Specifically, we implemented his-tag binding chemistry to design a new fluorinated amphiphile, RfNTA, using an improved one-step synthesis of RfOEG under Mitsunobu conditions. RfNTA introduces specific binding of protein at the fluorous-aqueous interface, which concentrates and orients proteins at the interface, even in the presence of other surfactants. We then applied this approach to the crystallization of a his-tagged membrane protein, Reaction Center from Rhodobacter sphaeroides, performed 2400 crystallization trials, and showed that this approach can increase the range of crystal-producing conditions, the success rate at a given condition, the rate of nucleation, and the quality of the crystal formed.

  15. Reengineering the optical absorption cross-section of photosynthetic reaction centers.

    Science.gov (United States)

    Dutta, Palash K; Lin, Su; Loskutov, Andrey; Levenberg, Symon; Jun, Daniel; Saer, Rafael; Beatty, J Thomas; Liu, Yan; Yan, Hao; Woodbury, Neal W

    2014-03-26

    Engineered cysteine residues near the primary electron donor (P) of the reaction center from the purple photosynthetic bacterium Rhodobacter sphaeroides were covalently conjugated to each of several dye molecules in order to explore the geometric design and spectral requirements for energy transfer between an artificial antenna system and the reaction center. An average of 2.5 fluorescent dye molecules were attached at specific locations near P. The enhanced absorbance cross-section afforded by conjugation of Alexa Fluor 660 dyes resulted in a 2.2-fold increase in the formation of reaction center charge-separated state upon intensity-limited excitation at 650 nm. The effective increase in absorbance cross-section resulting from the conjugation of two other dyes, Alexa Fluor 647 and Alexa Fluor 750, was also investigated. The key parameters that dictate the efficiency of dye-to-reaction center energy transfer and subsequent charge separation were examined using both steady-state and time-resolved fluorescence spectroscopy as well as transient absorbance spectroscopy techniques. An understanding of these parameters is an important first step toward developing more complex model light-harvesting systems integrated with reaction centers. PMID:24568563

  16. Photosynthetic bacterial growth and productivity under continuous illumination or diurnal cycles with olive mill wastewater as feedstock

    Energy Technology Data Exchange (ETDEWEB)

    Eroglu, Ela [Middle East Technical University, Dept. of Chemical Engineering, 06531, Ankara (Turkey); University of California, Dept. of Plant and Microbial Biology, Berkeley, CA 94720-3102 (United States); Gunduz, Ufuk; Yucel, Meral [Middle East Technical University, Dept. of Biology, 06531, Ankara (Turkey); Eroglu, Inci [Middle East Technical University, Dept. of Chemical Engineering, 06531, Ankara (Turkey)

    2010-06-15

    Photofermentative hydrogen production from olive mill wastewater by Rhodobacter sphaeroides O.U.001 was investigated under different regimes of illumination. The analysis included measurements of biomass accumulation, H{sub 2}-production, high-value bio-product accumulation (polyhydroxybutyrate and carotenoid) and measurements of the medium pH as a function of growth and productivity. Batch cultures were grown under continuous light (CL) or 12 h light/12 h dark (12L/12D) diurnal cycles. Growth under CL or 12L/12D cycles yielded about the same amount of biomass (0.5 g dry cell weight per L culture) and volume of H{sub 2} gas (50 ml H{sub 2} per L culture). On the other hand, 12L/12D cultures showed a pronounced lag in biomass and H{sub 2} accumulation. Advances described in the work would find application in lowering operational costs for hydrogen production by better management of the energy source and cheap feedstock utilization. Compare to CL, equivalent amount of hydrogen gas accumulation within shorter time interval denoted to have two times higher hydrogen production rate and light conversion efficiencies via diurnal cycles, which can yield 50% savings on consumed energy source. (author)

  17. Mimicking respiratory phosphorylation using purified enzymes.

    Science.gov (United States)

    von Ballmoos, Christoph; Biner, Olivier; Nilsson, Tobias; Brzezinski, Peter

    2016-04-01

    The enzymes of oxidative phosphorylation is a striking example of the functional association of multiple enzyme complexes, working together to form ATP from cellular reducing equivalents. These complexes, such as cytochrome c oxidase or the ATP synthase, are typically investigated individually and therefore, their functional interplay is not well understood. Here, we present methodology that allows the co-reconstitution of purified terminal oxidases and ATP synthases in synthetic liposomes. The enzymes are functionally coupled via proton translocation where upon addition of reducing equivalents the oxidase creates and maintains a transmembrane electrochemical proton gradient that energizes the synthesis of ATP by the F1F0 ATP synthase. The method has been tested with the ATP synthases from Escherichia coli and spinach chloroplasts, and with the quinol and cytochrome c oxidases from E. coli and Rhodobacter sphaeroides, respectively. Unlike in experiments with the ATP synthase reconstituted alone, the setup allows in vitro ATP synthesis under steady state conditions, with rates up to 90 ATP×s(-1)×enzyme(-1). We have also used the novel system to study the phenomenon of "mild uncoupling" as observed in mitochondria upon addition of low concentrations of ionophores (e.g. FCCP, SF6847) and the recoupling effect of 6-ketocholestanol. While we could reproduce the described effects, our data with the in vitro system does not support the idea of a direct interaction between a mitochondrial protein and the uncoupling agents as proposed earlier. PMID:26707617

  18. Ionic liquids effects on the permeability of photosynthetic membranes probed by the electrochromic shift of endogenous carotenoids.

    Science.gov (United States)

    Malferrari, Marco; Malferrari, Danilo; Francia, Francesco; Galletti, Paola; Tagliavini, Emilio; Venturoli, Giovanni

    2015-11-01

    Ionic liquids (ILs) are promising materials exploited as solvents and media in many innovative applications, some already used at the industrial scale. The chemical structure and physicochemical properties of ILs can differ significantly according to the specific applications for which they have been synthesized. As a consequence, their interaction with biological entities and toxicity can vary substantially. To select highly effective and minimally harmful ILs, these properties need to be investigated. Here we use the so called chromatophores--protein-phospholipid membrane vesicles obtained from the photosynthetic bacterium Rhodobacter sphaeroides--to assess the effects of imidazolinium and pyrrolidinium ILs, with chloride or dicyanamide as counter anions, on the ionic permeability of a native biological membrane. The extent and modalities by which these ILs affect the ionic conductivity can be studied in chromatophores by analyzing the electrochromic response of endogenous carotenoids, acting as an intramembrane voltmeter at the molecular level. We show that chromatophores represent an in vitro experimental model suitable to probe permeability changes induced in cell membranes by ILs differing in chemical nature, degree of oxygenation of the cationic moiety and counter anion.

  19. Energy transfer in an LH4-like light harvesting complex from the aerobic purple photosynthetic bacterium Roseobacter denitrificans

    Energy Technology Data Exchange (ETDEWEB)

    Niedzwiedzki, Dariusz; Fuciman, Marcel; Frank, Harry A; Blankenship, R. E.

    A peripheral light-harvesting complex from the aerobic purple bacterium Roseobacter (R.) denitrificans was purified and its photophysical properties characterized. The complex contains two types of pigments, bacteriochlorophyll (BChl) a and the carotenoid (Car) spheroidenone and possesses unique spectroscopic properties. It appears to lack the B850 bacteriochlorophyll a Q{sub y} band that is typical for similar light-harvesting complex 2 antennas. Circular dichroism and low temperature steady-state absorption spectroscopy revealed that the B850 band is present but is shifted significantly to shorter wavelengths and overlaps with the B800 band at room temperature. Such a spectral signature classifies this protein as a member of the light-harvesting complex 4 class of peripheral light-harvesting complexes, along with the previously known light-harvesting complex 4 from Rhodopseudomonas palustris. The influence of the spectral change on the light-harvesting ability was studied using steady-state absorption, fluorescence, circular dichroism, femtosecond and microsecond time-resolved absorption and time-resolved fluorescence spectroscopies. The results were compared to the properties of the similar (in pigment composition) light-harvesting complex 2 from aerobically grown Rhodobacter sphaeroides and are understood within the context of shared similarities and differences and the putative influence of the pigments on the protein structure and its properties.

  20. Binding Site Recognition and Docking Dynamics of a Single Electron Transport Protein: Cytochrome c2.

    Science.gov (United States)

    Singharoy, Abhishek; Barragan, Angela M; Thangapandian, Sundarapandian; Tajkhorshid, Emad; Schulten, Klaus

    2016-09-21

    Small diffusible redox proteins facilitate electron transfer in respiration and photosynthesis by alternately binding to their redox partners and integral membrane proteins and exchanging electrons. Diffusive search, recognition, binding, and unbinding of these proteins often amount to kinetic bottlenecks in cellular energy conversion, but despite the availability of structures and intense study, the physical mechanisms controlling redox partner interactions remain largely unknown. The present molecular dynamics study provides an all-atom description of the cytochrome c2-docked bc1 complex in Rhodobacter sphaeroides in terms of an ensemble of favorable docking conformations and reveals an intricate series of conformational changes that allow cytochrome c2 to recognize the bc1 complex and bind or unbind in a redox state-dependent manner. In particular, the role of electron transfer in triggering a molecular switch and in altering water-mediated interface mobility, thereby strengthening and weakening complex formation, is described. The results resolve long-standing discrepancies between structural and functional data. PMID:27508459

  1. The kinetic model for slow photoinduced electron transport in the reaction centers of purple bacteria.

    Science.gov (United States)

    Serdenko, T V; Barabash, Y M; Knox, P P; Seifullina, N Kh

    2016-12-01

    The present work is related to the investigation of slow kinetics of electron transport in the reaction centers (RCs) of Rhodobacter sphaeroides. Experimental data on the absorption kinetics of aqueous solutions of reaction centers at different modes of photoexcitation are given. It is shown that the kinetics of oxidation and reduction of RCs are well described by the sum of three exponential functions. This allows to suggest a two-level kinetic model for electron transport in the RC as a system of four electron-conformational states which correspond to three balance differential equations combined with state equation. The solution of inverse problem made it possible to obtain the rate constant values in kinetic equations for different times and intensities of exciting light. Analysis of rate constant values in different modes of RC excitation allowed to suggest that two mechanisms of structural changes are involved in RC photo-oxidation. One mechanism leads to the increment of the rate of electron return, another one-to its drop. Structural changes were found out to occur in the RCs under incident light. After light was turned off, the reduction of RCs was determined by the second mechanism. PMID:27271854

  2. Pleiotropic effects of puf interposon mutagenesis on carotenoid biosynthesis in Rubrivivax gelatinosus. A new gene organization in purple bacteria.

    Science.gov (United States)

    Ouchane, S; Picaud, M; Vernotte, C; Reiss-Husson, F; Astier, C

    1997-01-17

    Rubrivivax gelatinosus mutants affected in the carotenoid biosynthesis pathways were created by interposon mutagenesis within the puf operon. Genetic and biochemical analysis of several constructed mutants suggest that at least crtC is localized downstream of the puf operon and that it is cotranscribed with this operon. Sequence analysis confirmed the genetic data and showed the presence of crtD and crtC genes downstream of the puf operon, a localization different from that known for other purple bacteria. Inactivation of the crtD gene indicated that the two crt genes are cotranscribed and that they are involved not only in the hydroxyspheroidene biosynthesis pathway as in Rhodobacter sphaeroides and R. capsulatus, but also in the spirilloxanthin biosynthesis pathway. Carotenoid genes implicated in the spirilloxanthin biosynthesis pathway were thus identified for the first time. Furthermore, analysis of carotenoid synthesis in the mutants gave genetic evidence that crtD and crtC genes are cotranscribed with the puf operon using the oxygen-regulated puf promoter.

  3. Overall energy conversion efficiency of a photosynthetic vesicle

    Science.gov (United States)

    Sener, Melih; Strumpfer, Johan; Singharoy, Abhishek; Hunter, C Neil; Schulten, Klaus

    2016-01-01

    The chromatophore of purple bacteria is an intracellular spherical vesicle that exists in numerous copies in the cell and that efficiently converts sunlight into ATP synthesis, operating typically under low light conditions. Building on an atomic-level structural model of a low-light-adapted chromatophore vesicle from Rhodobacter sphaeroides, we investigate the cooperation between more than a hundred protein complexes in the vesicle. The steady-state ATP production rate as a function of incident light intensity is determined after identifying quinol turnover at the cytochrome bc1 complex (cytb⁢c1) as rate limiting and assuming that the quinone/quinol pool of about 900 molecules acts in a quasi-stationary state. For an illumination condition equivalent to 1% of full sunlight, the vesicle exhibits an ATP production rate of 82 ATP molecules/s. The energy conversion efficiency of ATP synthesis at illuminations corresponding to 1%–5% of full sunlight is calculated to be 0.12–0.04, respectively. The vesicle stoichiometry, evolutionarily adapted to the low light intensities in the habitat of purple bacteria, is suboptimal for steady-state ATP turnover for the benefit of protection against over-illumination. DOI: http://dx.doi.org/10.7554/eLife.09541.001 PMID:27564854

  4. The role of pH control on biohydrogen production by single stage hybrid dark- and photo-fermentation.

    Science.gov (United States)

    Zagrodnik, R; Laniecki, M

    2015-10-01

    The role of pH control on biohydrogen production by co-culture of dark-fermentative Clostridium acetobutylicum and photofermentative Rhodobacter sphaeroides was studied. Single stage dark fermentation, photofermentation and hybrid co-culture systems were studied at different values of controlled and uncontrolled pH. Increasing pH during dark fermentation resulted in lower hydrogen production rate (HPR) and longer lag time for both controlled and uncontrolled conditions. However, it only slightly affected cumulative H2 volume. Results have shown that pH control at pH 7.5 increased photofermentative hydrogen production from 0.966 to 2.502 L H2/L(medium) when compared to uncontrolled process. Fixed pH value has proven to be an important control strategy also for the hybrid process and resulted in obtaining balanced co-culture of dark and photofermentative bacteria. Control of pH at 7.0 was found optimum for bacteria cooperation in the co-culture what resulted in obtaining 2.533 L H2/L(medium) and H2 yield of 6.22 mol H2/mol glucose.

  5. Global analysis of photosynthesis transcriptional regulatory networks.

    Science.gov (United States)

    Imam, Saheed; Noguera, Daniel R; Donohue, Timothy J

    2014-12-01

    Photosynthesis is a crucial biological process that depends on the interplay of many components. This work analyzed the gene targets for 4 transcription factors: FnrL, PrrA, CrpK and MppG (RSP_2888), which are known or predicted to control photosynthesis in Rhodobacter sphaeroides. Chromatin immunoprecipitation followed by high-throughput sequencing (ChIP-seq) identified 52 operons under direct control of FnrL, illustrating its regulatory role in photosynthesis, iron homeostasis, nitrogen metabolism and regulation of sRNA synthesis. Using global gene expression analysis combined with ChIP-seq, we mapped the regulons of PrrA, CrpK and MppG. PrrA regulates ∼34 operons encoding mainly photosynthesis and electron transport functions, while CrpK, a previously uncharacterized Crp-family protein, regulates genes involved in photosynthesis and maintenance of iron homeostasis. Furthermore, CrpK and FnrL share similar DNA binding determinants, possibly explaining our observation of the ability of CrpK to partially compensate for the growth defects of a ΔFnrL mutant. We show that the Rrf2 family protein, MppG, plays an important role in photopigment biosynthesis, as part of an incoherent feed-forward loop with PrrA. Our results reveal a previously unrealized, high degree of combinatorial regulation of photosynthetic genes and significant cross-talk between their transcriptional regulators, while illustrating previously unidentified links between photosynthesis and the maintenance of iron homeostasis.

  6. A molecular genetic analysis of carotenoid biosynthesis and the effects of carotenoid mutations on other photosynthetic genes in Rhodobacter capsulatus

    Energy Technology Data Exchange (ETDEWEB)

    Armstrong, G.A.

    1989-04-01

    The nine known R. capsulatus carotenoid genes are contained within the 46 kilobase (kb) photosynthesis gene cluster. An 11 kb subcluster containing eight of these genes has been cloned and its nucleotide sequence determined. A new gene, crtK, has been located in the middle of the subcluster. The carotenoid gene cluster contains sequences homologous to Escherichia coli ..omega../sup 70/ promoters, rho-independent transcription terminators, and prokaryotic transcriptional factor binding sites. The phenotypes and genotypes of ten transposon Tn5.7 insertion mutations within the carotenoid gene cluster have been analyzed, by characterization of the carotenoids accumulated and high resolution mapping of the Tn5.7 insertions. The enzymatic blockages in previously uncharacterized early carotenoid mutants have been determined using a new in vitro synthesis system, suggesting specific roles for the CrtB and CrtE gene products. The expression of six of the eight carotenoid genes in the cluster is induced upon the shift from dark chemoheterotrophic to anaerobic photosynthetic growth. The magnitude of the induction is equivalent to that of genes encoding structural photosynthesis polypeptides, although the carotenoid genes are induced earlier after the growth shift. Different means of regulating photosynthesis genes in R. capsulatus are discussed, and a rationale for the temporal pattern of expression of the carotenoid genes during photosynthetic adaptation is presented. Comparison of the deduced amino acid sequences of the two dehydrogenases of the R. capsulatus carotenoid biosynthesis pathway reveals two regions of strong similarity. The effect of carotenoid mutations on the photosynthetic phenotype has been studied by examining growth rates, pigments, pigment-protein complexes and gene expression for a complete set of carotenoid mutants. 161 refs.

  7. A molecular genetic analysis of carotenoid biosynthesis and the effects of carotenoid mutations on other photosynthetic genes in Rhodobacter capsulatus

    International Nuclear Information System (INIS)

    The nine known R. capsulatus carotenoid genes are contained within the 46 kilobase (kb) photosynthesis gene cluster. An 11 kb subcluster containing eight of these genes has been cloned and its nucleotide sequence determined. A new gene, crtK, has been located in the middle of the subcluster. The carotenoid gene cluster contains sequences homologous to Escherichia coli ω70 promoters, rho-independent transcription terminators, and prokaryotic transcriptional factor binding sites. The phenotypes and genotypes of ten transposon Tn5.7 insertion mutations within the carotenoid gene cluster have been analyzed, by characterization of the carotenoids accumulated and high resolution mapping of the Tn5.7 insertions. The enzymatic blockages in previously uncharacterized early carotenoid mutants have been determined using a new in vitro synthesis system, suggesting specific roles for the CrtB and CrtE gene products. The expression of six of the eight carotenoid genes in the cluster is induced upon the shift from dark chemoheterotrophic to anaerobic photosynthetic growth. The magnitude of the induction is equivalent to that of genes encoding structural photosynthesis polypeptides, although the carotenoid genes are induced earlier after the growth shift. Different means of regulating photosynthesis genes in R. capsulatus are discussed, and a rationale for the temporal pattern of expression of the carotenoid genes during photosynthetic adaptation is presented. Comparison of the deduced amino acid sequences of the two dehydrogenases of the R. capsulatus carotenoid biosynthesis pathway reveals two regions of strong similarity. The effect of carotenoid mutations on the photosynthetic phenotype has been studied by examining growth rates, pigments, pigment-protein complexes and gene expression for a complete set of carotenoid mutants. 161 refs

  8. La demence chez le patient parkinsonien: facteurs de risque, diagnostic et traitement.

    OpenAIRE

    BAKAY, Sara; Bechet, Sophie; BARJONA MORGADO DE MOURA, Aude; Delvaux, Valérie; Salmon, Eric; Garraux, Gaëtan

    2011-01-01

    Aside from limb tremor, bradykinesia, rigidity and gait disturbances, Parkinson's disease (PD) is also characterized by non-motor symptoms. A cognitive decline can occur early in the disease course and undoubtedly impact of the patient's quality of life. Dementia affects 80% of patients 20 years after disease onset but a small subgroup of patients remain free of dementia even after decades with PD. Risk factors and diagnosis of dementia can be easily assessed using bed-side clinical instrumen...

  9. Evolution de la stratégie multicanal chez Vedia S.A.

    OpenAIRE

    Hug, Nicole; Morand, Jean-Claude

    2009-01-01

    La société Vedia S.A. est active dans le domaine de la vente par correspondance sur le territoire Suisse. Elle vend des articles de tout genre pour une utilisation quotidienne sous deux noms de marque : Vedia et Kays. La nouvelle stratégie qu’aimerait poursuivre la société est de se lancer dans le multicanal de distribution en ouvrant un magasin qui lui permettera en partie de liquider de la marchandise à prix réduit. Lors d’une analyse de l’environnement démographique et économique il en est...

  10. Noms de personne et expression des ambitions matrimoniales chez les Bwa du Mali

    OpenAIRE

    Leguy, Cécile

    2008-01-01

    Que nous apprennent les noms de personne dans un contexte où la nomination peut être perçue comme un moyen d’expression subtil d’opinions qui ne sauraient se dire explicitement ? À partir d’un sujet de préoccupation fortement présent dans les messages des noms portés par les Bwa du Mali, le mariage, nous verrons comment l’anthropologue, attentif au contexte de la nomination et à l’identité du donneur de nom, peut accéder à une autre dimension de la vie sociale, au-delà des pratiques et des di...

  11. Quelques monstruosités chez les Cynoglossidés

    NARCIS (Netherlands)

    Chabanaud, Paul

    1949-01-01

    Cynoglossus polytaenia (Bleeker). Zoölogisch Museum (Amsterdam), n° 1276. Coll. Laboratoire pour l’Exploration de la Mer (Batavia), près Penang. Longueur totale 117 mm. Longueur étalon 106 mm. Fig. 1. A première vue, la nageoire dorsale parait interrompue vers le milieu de sa longueur, sur une certa

  12. Philosophie de la psychologie et psychanalyse chez Freud : enjeux épistémologiques contemporains

    OpenAIRE

    Limikou Biekela, Alpin Dieudonné

    2014-01-01

    What where the main types of psychological knowladge used by Freud which contributed to the emergence of psychoanalytic movement? How did Freud use these main types of psychological knowladge in the context of original construction? In spite of the abundant literature concerning these questions which appaer simple, the answers aren't uncontroversial. This difficulty isn't recent, Freud has been already studied this matter in Contribution to the History of Psychoanalysis movement (1914) and My...

  13. Le choix de la foi chalcédonienne chez les Arméniens

    Directory of Open Access Journals (Sweden)

    Isabelle Augé

    2011-09-01

    Full Text Available L’article s’intéresse aux Arméniens professant, à la différence de leurs compatriotes, la foi chalcédonienne. Un tableau aussi précis que possible de l’implantation géographique des communautés, qui varie suivant les siècles et les vicissitudes politiques et militaires, est d’abord dressé. L’auteur évoque ensuite deux cas bien documentés (ce qui est rare, étant donné le caractère très lacunaire des sources d’adoption, par des groupes d’Arméniens, de la foi chalcédonienne, avant de s’attarder sur les aspects culturels et artistiques. Enfin, l’attitude des Arméniens restés « grégoriens » à l’égard des Arméniens chalcédoniens, qui oscille entre tolérance et persécution, est étudiée.This article is devoted to Armenians advocating Chalcedonian creed, contrary to their kinsmen. A very minute picture of the geographical distribution of these communities, varying through time and political or military troubles, is drawn as an introduction. Then the author provides two very well-documented examples–notably an extremely rare instance given the incomplete nature of such sources–of conversion by Armenian groups to the Chalcedonian creed, before examining the related cultural and artistic aspects. Lastly, a study if done of the attitude of the still ‘Gregorian’ Armenians toward the Chalcedonian Armenians, wavering between tolerance and persecution.

  14. Reproduction et Diversité Génétique chez Parkia biglobosa (Jacq.) G. Don

    OpenAIRE

    Sina, S.

    2006-01-01

    Parkiabiglobosa(Jacq.)G.Don, African locust bean, is one of the 34 known species of the genusParkiawhose centre of origin isSouth America. It is anagroforestrytree species spread throughout the Africansudaniansavannas, fromSenegalin the West toUgandain the East. P.biglobosa is also an important socio-economic species in high demand by local communities for its multiple amenities and uses (food, traditional medicine and pharmacy, preservation and improvement of soil fertility, rites and custom...

  15. L'activite de deplacement et le reperage de la nourriture chez le bar juvenile captif

    OpenAIRE

    Anthouard, M; Paris, J

    1983-01-01

    Movement activity and localization of food were studied dynamically with the objective of establishing the capacities of behavioral adaptation of the young Dicentrarchus labrax faced with a novel situation. The role played by previous rearing conditions was demonstrated, the level of stimulation being a sensitive intervening factor (currents associated with the food). The data show the favourable effects of such treatment, and are in agreement with work carried out on higher vertebrates, whic...

  16. Brain SPECT in childhood; Temp cerebrale chez l'enfant

    Energy Technology Data Exchange (ETDEWEB)

    Tranquart, F.; Saliba, E.; Prunier, C.; Baulieu, F.; Besnard, J.C.; Guilloteau, D.; Baulieu, J.L. [Hopital Bretonneau, Service de Medecine Nucleaire, Unite Inserm 316, 37 - Tours (France)

    2001-04-01

    The modalities and the indications of perfusion and neurotransmission SPECT in childhood are presented. The perfusion as well as neurotransmission tracers have not yet authorization for use in children; they have to be used by prescription of magistral preparation or in research protocols. The radioprotection rules have to be strictly respected. The most frequent indication of perfusion SPECT is pharmacologically resistant epilepsy; the ictal SPECT before surgery allows the localization of the epileptogenic focus. Other indications are relevant in the prognosis of neonatal anoxia and encephalitis. In psychiatric disorders, especially in autism, the interest is the physiopathological approach of the brain dysfunctions. The neurotransmission SPECT is emerging as a consequence of the development of new radiotracer, as the dopaminergic system ligands. The decrease of the dopamine D2 receptors in the striatum can be imaged and quantified in the neonate. The lesions of dopamine system seem to be a consequence of the neonatal hypoxia-ischemia and it is predictive of motor sequelae. Brain SPECT should become a routine examination in child neurologic and psychiatric disorders. (authors)

  17. Apparence et jeu, valeur cultuelle et valeur d’exposition chez Walter Benjamin

    Directory of Open Access Journals (Sweden)

    Anne Boissière

    2007-05-01

    Full Text Available À travers le couple valeur cultuelle/valeur d’exposition présent dans son essai sur la reproductibilité technique, Walter Benjamin introduit une conception historique et dialectique de l’apparence. La valeur contemplative que l’esthétique philosophique accorde à la perception esthétique est relativisée au bénéfice d’une conception pratique de la perception, anciennement tangible dans l’activité magique mais possiblement redéployée avec la photographie et le cinéma. Ce texte veut rendre justice à la dimension pratique et politique qui sous-tend la réflexion de Benjamin sur la reproduction technique : la perception auratique est envisagée comme un moment historique indissociablement lié au développement de la technique.By way of the couple cult-value/exhibition-value as present in his essay on artwork and technical reproduction, Walter Benjamin introduces a historical as well as dialectical theory of appearance. The contemplative attitude often identified with aesthetic perception in philosophical aesthetics is thus deconstructed in favour of a practical mode of perception, formely tangible in magical activity but possibly recovered with photography and cinema. The present article proposes to do justice to the practical and political thought that buttresses Benjamin’s reflection on technical reproducibility: auratic perception is envisaged as a historical moment ineluctably linked to the development of technology.

  18. La perception gustative et la consommation des tannins chez le maki (Lemur catta)

    OpenAIRE

    Peronny, Sylvie

    2005-01-01

    Le comportement alimentaire des primates varie en fonction de la disponibilité des ressources donc des saisons, et du choix de l'animal, facteur lié à des paramètres individuels. Les aliments consommés sont choisis en fonction de leur chimie (présence de nutriments, de composés toxiques...), et c'est le système gustatif qui permet de faire le lien entre un primate et les aliments qu'il consomme. Les tannins, toxiques à forte dose, sont les composés secondaires des plantes les plus répandus. L...

  19. Les orchidées comestibles chez le peuple Bagam, au Cameroun

    Directory of Open Access Journals (Sweden)

    Menzepoh, SB.

    2011-01-01

    Full Text Available Edible orchids by the Bagam tribe in Cameroon. In the Zambezian region of Africa, tuber orchids are renowned for their food, medicinal and economic values. In central Africa and in Cameroon in particular, socio-economic role of orchids is still to be documented. The current paper focuses on two orchids, Habenaria keayi Summerh. and Habenaria zambesina Rchb.f. which tuber and roots respectively are used to prepare a food called "napssié" or ground meat by the Bagam tribe in the subdivision of Galim, Western region of Cameroon. The paper also mentions their socio-economic role, threat and pleads for their domestication.

  20. Pr\\'evention des escarres chez les parapl\\'egiques : une nouvelle approche par \\'electrostimulation linguale

    OpenAIRE

    Moreau-Gaudry, Alexandre; Prince, Anne; Demongeot, Jacques; Payan, Yohan

    2007-01-01

    Pressure ulcers are recognized as a major health issue in individuals with spinal cord injuries and new approaches to prevent this pathology are necessary. An innovative health strategy is being developed through the use of computer and sensory substitution via the tongue in order to compensate for the sensory loss in the buttock area for individuals with paraplegia. This sensory compensation will enable individuals with spinal cord injuries to be aware of a localized excess of pressure at th...

  1. Extended visual regions among the deaf; L`extension des aires visuelles chez les sourds

    Energy Technology Data Exchange (ETDEWEB)

    Neville, H. [Oregon Univ., Eugene, OR (United States); Bavelier, D. [Georgetown Univ., Washington, DC (United States)

    1996-07-01

    Whatever is the source of the deafness (genetic or acquired in the childhood) it leads to a partial re-arrangement of brain. It has been shown at animals that nerve cells of the auditive cortex acquire some characteristics of the visual nerve cells. At men, the NMR imaging confirms it: it seems that a part of the visual cortex appropriates some cortex zones which are normally intended to audition. It has been verified too that the deaf language solicit more the right hemisphere than the spoken language. (O.M.). 2 refs.

  2. Les enjeux stratégiques de la théorie du discours chez Foucault

    Directory of Open Access Journals (Sweden)

    Corneliu Bilba

    2014-12-01

    Full Text Available In order to fully understand Michel Foucault’s archeology of knowledge it is necessary to put it not only in the context of the discourse theories of the French school, but also in that of the linguistic theories of science. On the one hand, Foucault rejects the representational theory of scientific language (developed by Carnap and others. In his analysis of the discourse of the human sciences, with its complicated definition of the statement (énoncé, he aims to show that we cannot limit the language of knowledge to a vocabulary. On the other hand, Foucault’s approach is a serious challenge to structuralism because it is impossible to analyze the language of savoirs without taking into account the statement’s correlate (the referent issue. If the discourse of sciences is an artificial vocabulary created by means of the purification of the natural language, Saussure’s semiology could not compete against the conceptual dynamics of representational semiotics, and should admit that, in the cognitive usage, signs are representations. Therefore, Foucault admits that the statement has a correlate, that this correlate is not a physical object and that it functions as a historical structure of the discourse. This structure (épistémè can be seen as a norm; the changing of this norm cannot be identified but in the archive and its description is always retrospective, structural and archaeological.

  3. Connaissances actualisées des maladies rares zoonotiques chez la femme enceinte

    OpenAIRE

    Duval, Camille

    2014-01-01

    De nombreuses femmes travaillent et vivent au contact d’animaux. La grossesse peut représenter pour ces femmes une période à risque vis-à-vis de nombreuses zoonoses. Certaines zoonoses comme la toxoplasmose sont bien connues et le risque vis-à-vis des femmes enceintes est maitrisé, mais beaucoup constituent des maladies rares peu étudiées et souvent mal connues des médecins. Ce travail est une recherche bibliographique sur les maladies rares zoonotiques touchant les femmes enceintes. Il fait ...

  4. Ontogenèse de l’esprit vichien et structures imaginatives chez Hegel

    Directory of Open Access Journals (Sweden)

    Arab Kennouche

    2013-07-01

    Full Text Available Ontogenesis of spirit in Vico and imaginative structures in Hegel. This essay discusses somefunctions of imagination as Vico depicted them in their biblical, historical and ontogenetical aspects. The Vichian nascimento of thought as imagination aims at defining the realrelationship between mind and body outside their often false opposition. The archeology of thinking does not rest on a presumptive centered substance governing the human flesh and passions, but on a network of powerful images, enabling the first humans to implement their faculty of intellection as acuity. Reason is absent from the first processes of intelligence, as they are depicted in the New Science, first of all with the “Second Fall”. Moving from here, the paper proposes a comparison with the structure of imagination in Hegel’s philosophy, taken as a model of the primacy of a logic and divinereason, and suggests a path to interpretate even Hegel’s concept of Geist through Vico’s laws of imagination.

  5. Synopsis des dermatomycoses invasives chez l'immunodéprimé.

    OpenAIRE

    Quatresooz, Pascale; Arrese Estrada, Jorge; Pierard, Gérald

    2003-01-01

    The immune system plays a prominent role in the defense against a wide variety of pathogen fungi. Thus, the immunocompromised patient becomes a potential victim of mycoses originating from the skin. These mycoses may become invasive and a fatal issue is possible. In other circumstances, the inoculation site is pulmonary or digestive, and the cutaneous lesions represent secondary localizations.

  6. Quelques cérémonies chez les Oudmourtes du Bachkortostan

    OpenAIRE

    Toulouze, Eva; Niglas, Liivo

    2016-01-01

    Au cours du mois de juin 2013, nous avons passé un mois dans le village oudmourte de Bal’zuga, au Nord du Bachkortostan dans le raïon de Tatyšly. Les villages oudmourtes de cette région forment une zone compacte où la langue de communication quotidienne, au niveau aussi bien de la famille que du village, de la coopérative de production ou de l’administration, est l’oudmourte. Nous avions, en venant ici, un objectif précis. Le mois de juin en effet, le mois du solstice, marquant la fin des tra...

  7. Valeurs du contact et valeurs en contact dans les pratiques du SMS chez les adolescents

    OpenAIRE

    Raluca MOISE

    2010-01-01

    The SMS (Short Message Service) has become a phenomenon which comprises diverse public reactions. Different attitudes contribute creating multiple representations of this phenomenon (the mass-media, teachers, TV shows or specific websites). The SMS becomes a culture formed by very different uses to its numerous and diverse users. We think that the SMS passed over its initial functions, those of communication and socialization, becoming a frame for creativity and artistic innovation.

  8. Syntaxe et sémantique chez Tesnière

    Directory of Open Access Journals (Sweden)

    Paul Garde

    1994-12-01

    Full Text Available Ce qui frappe avant tout dans les Eléments de syntaxe structurale de Lucien Tesnière, c'est leur caractère exhaustif: il s'agit d' une somme, rendant compte potentiellement de tous les phénomènes syntaxiques de toutes les langues. Aucun des autres grands linguistes du XX0 siècle ne nous presénte une oeuvre comparable, tous, de Hjelmslev à Chomsky, insistent davantage sur des questions de méthode sans en rechercher l’application à tous les problèmes possibles.

  9. Religion publique et médiation religieuse chez les musulmans mauriciens

    NARCIS (Netherlands)

    Eisenlohr, Patrick

    2014-01-01

    The uses of sound reproduction among Mauritian Muslims illustrate the links between public religion and religious mediation. These two dimensions of religion rely on material objects and media technologies, coalescing in what are frequently the same media practices. In this essay I investigate the a

  10. LES EFFETS DE L'HYPOXIE CHEZ LE SUJET SAIN ET PATHOLOGIQUE

    OpenAIRE

    Costalat, Guillaume

    2015-01-01

    This thesis investigates the effects of hypoxia in both healthy and diseased areas. Using freediving as a base, hemodynamic adjustments triggered by voluntary breath-holding were studied in trained breath-hold divers (study 1) to be then compared with non-divers (study 2). Moreover, both hemodynamic and ventilatory responses to hypoxia were investigated in trained breath-hold divers (study 3). Plasma adenosine concentration was also measured to clarify pathophysiological mechanisms underlying...

  11. L'ironie dans l'allégorie chez Rutebeuf

    Directory of Open Access Journals (Sweden)

    Špela Žakelj

    2007-12-01

    Full Text Available Occupant une place très importante parmi les auteurs français du XIII siècle, Rutebeuf se sert dans sa poésie morale et satirique de l'allégorie, figure rhétorique typique pour le Moyen Age, dans la poésie liée surtout à la thématique du voyage. Dans les suvres de Rutebeuf l'allégorie est jointe le plus souvent à la satire, genre de prédiléction du discours ironique. Se dressant de manière symbolique contre l'écroulement des valeurs traditionnelles l'auteur prend pour l'objet de son ironie la corruption de la société contemporaine, surtout celle des ordres mendinats, coupables selon lui pour l'emprise des vices sur l'humanité. Pour éviter la généralization avec laquelle le systeme allégorique des personifications empreint perspective satirique et ironique Rutebeuf combine les modèles allégoriques différents, créant ainsi une situation a priori dramatique dont témoignent par exemple ses suvres Le débat du croisé et du décroisé, la Leçon sur Hypocrisie et Humilité ou Le dit du mensonge.

  12. Le vaccin antipneumococcique. L'efficacité chez les 55 ans et plus.

    OpenAIRE

    MARCHAND, R

    1993-01-01

    Three recent articles are examined in which research using the double-blind randomised clinical trial, the case control study, and the quasi-cohort study is described. Understanding the advantages and disadvantages of these methods makes it easier to grasp the pneumococcal vaccine controversy and make an informed choice.

  13. 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

    La réduction des teneurs en protéines des aliments pour porcelets peut se faire uniquement sous contrôle des apports en acides aminés (AA) indispensables tels que les AA ramifies (AAR) valine (Val), isoleucine (Ile) et leucine (Leu) susceptibles d’être déficitaires et d’altérer les performances de...

  14. Osseous eosinophilic granuloma in children; Le granulome eosinophile des os chez l'enfant

    Energy Technology Data Exchange (ETDEWEB)

    Leblan, I.; Gaucher, H.; Marinard, L.; Galloy, M.A.; Phi, I.N.; Hoeffel, J.C. [Hopital de Brabois-Vandoeuvre, 54 - Nancy (France). Service de radiologie

    2001-02-01

    Eosinophilic granuloma of bone or Langerhans cell histiocytosis is mostly uni-focal. It appears on plain X Ray as a solitary destructive lesion of long bones or flat bones. CT is useful to define the extension to the cortical bone and also to precisely localize the lesion when the anatomy is complex (hip, spine, base of the skull). MR is very useful in case of more aggressive lesions when there is extension to soft tissues. Differential diagnosis includes circumscribed osteitis and tumors prognosis is more serious in case of multiple lesions. (authors)

  15. Le principe de raison chez LeibnizEnjeux théoriques et pratiques

    OpenAIRE

    Chevalier, Jean-Marie

    2015-01-01

    Le principe de raison suffisante, explicitement formulé pour la première fois par Leibniz, postule que tous les faits ont une explication. Gottfried Wilhelm Leibniz (1646-1716). © DR À ce titre, il peut passer pour un principe d’intelligibilité de bonne méthode, constituant selon Leibniz l’un des deux fondements du raisonnement avec la non-contradiction. Mais son interprétation radicale, qui y voit une vérité nécessaire et illimitée dans son extension (incluant non seulement le monde actuel ...

  16. A la recherche de l'alg\\`ebre perdue: du c\\^ote de chez Gauss

    CERN Document Server

    Kozlov, P

    2008-01-01

    This paper is purely expositional. The statement of the Gauss criterion for constructibility of regular polygons is simple and well-known. We sketch an elementary proof of this criterion. We do not use the terms 'field extension', 'Galois group' and even 'group'. However, our presentation is a good way to learn (or recall) starting idea of the Galois theory. The paper is accessible for students familiar with elementary algebra (including complex numbers), and could be an interesting easy reading for mature mathematicians. The material is presented as a sequence of problems, which is peculiar not only to Zen monasteries but also to elite mathematical education (at least in Russia); most problems are presented with hints or solutions. An English version is followed by a more extended Russian version.

  17. Preoccupations sexuelles chez les jeunes pubertaires: Intrication des facteurs méso-psychologiques

    Directory of Open Access Journals (Sweden)

    M. schachter

    1951-12-01

    Full Text Available L'auteur présente quelques cas de jeunes gens d'âge pubertaire ou pré-pubertaire, vus pour des troubles "nerveux", des changements de l'humeur et pour des chutes dans l'efficience scolaire. L'étude psychologique et clinique montre le rôle joué par les préoccupations à caractère sexuel. L'auteur insiste sur les fautes éducatives de toutes sortes et montre l'utilité que possèdent les tests projectifs (Rorschach, Murray, van Lennep, en tant que moyens permettant de mieux connaître la personnalité de ces sujets. La thérapeutique doit tenir compte du rôle, de premier plan, joué par les facteurs mésologiques et psychologiques à la fois.

  18. Paix et démocratie chez Kreisky – deux processus dynamiques indissociables

    Directory of Open Access Journals (Sweden)

    Lise Barrière

    2009-12-01

    Full Text Available Bruno Kreisky, chancelier autrichien de 1970 à 1983 a, tout au long de sa carrière politique, manifesté un grand intérêt pour la construction de la paix et l’apaisement des conflits. Sa première action d’envergure eut lieu à partir de 1959, lorsqu’il devint ministre des Affaires étrangères autrichiennes et qu’il décida de s’emparer de la question du Tyrol méridional qui empoisonnait les relations entre l’Autriche et l’Italie depuis la fin de la Seconde Guerre mondiale. Pour tenter de mettre un terme à ce conflit, Kreisky privilégia la discussion avec l’Italie directement, puis ensuite par l’intermédiaire des Nations unies, lorsque les négociations bilatérales aboutirent à une impasse. Si Kreisky manifestait un tel intérêt pour la construction de la paix, c’est parce qu’il considérait que paix et démocratie étaient intimement liées. C’est également cette conviction qui le poussa à vouloir apaiser un conflit qui se déroula sur le territoire autrichien lui-même. Il s’agit du conflit à propos de la mise en place de panneaux bilingues en Carinthie. Dans ce cas, malgré ses efforts, Kreisky ne parvint pas à apaiser les opposants à la loi sur les panneaux bilingues qui refusaient et refusent toujours à l’heure actuelle de voir ériger des panneaux en allemand et en slovène dans les régions de Carinthie à forte minorité slovène.Bruno Kreisky, österreichischer Bundeskanzler von 1970 bis 1983, engagierte sich überaus stark in der Frage der Lösung (internationaler Konflikte. 1959 österreichischer Außenminister geworden, war der erste Konflikt, mit dem er sich auseinanderzusetzen hatte, die sog. „Südtirolfrage“. Überzeugt davon, dass sich diese nur im Rahmen der UNO lösen ließe, bestand der Chef der österreichischen Diplomatie 1960 darauf, das Problem den Vereinten Nationen vorzutragen. Die Vollversammlung der UNO verabschiedete in der Folge tatsächlich zwei Resolutionen, die sowohl Österreich wie Italien aufforderten, ihren Streit um Südtirol im Zuge von Verhandlungen beizulegen und so nach einer Lösung für das Problem zu suchen. Kreiskys großes Interesse für den Aufbau und die Erhaltung von Frieden resultierte aus seiner festen Überzeugung, Frieden und Demokratie seien auf das Engste miteinander verbunden. Aus dieser Haltung heraus erklärt sich auch sein Engagement im sog. „Ortstafelkonflikt“ – eine Auseinandersetzung um die Aufstellung zweisprachiger Ortsschilder (deutsch und slowenisch in Kärnten. Allerdings war Kreisky bei der Beilegung dieser Auseinandersetzung kein Erfolg beschieden. Im Oktober 1972 musste ein vorbereitetes „Ortstafelgesetz“ zurückgenommen werden, und bis heute wurden die in ihm eigentlich vorgesehenen zweisprachigen Ortsschilder nicht aufgestellt.

  19. La douleur comme « matrice » de la vie intérieure chez Nietzsche

    Directory of Open Access Journals (Sweden)

    Ciprian Jeler

    2011-06-01

    Full Text Available This paper attempts to put some order among the different notions of pain that are to be found in the Nietzschean philosophical corpus. It tries to show that there is a mutation of the Nietzschean concept of pain, from the notion of pain as evaluation to that of pain as localization of a commotion. Therefore pain is not in itself the source of a reaction, but is actually a consequence of a commotion that a reaction has already addressed by the time of the appearance of pain. A deeper notion of pain is therefore sketched here, one that depicts it as an illusory reaction, destined at separating the global commotion of the organism from its alleged localized cause, thus separating the action from the agent and postponing the facing of the global effect of the commotion. It is for this reason that pain becomes a kind of “matrix” for the understanding of our interior life for Nietzsche, as well as a philosophical indicator of his theoretical adversaries. Finally, the end of this article attempts to show that certain positive indications for a different status of pain might serve as guiding lines for the uncovering of a Nietzschean theory of action.

  20. Maintien de l’ornementation mutuelle chez le manchot royal (Aptenodytes patagonicus)

    OpenAIRE

    Keddar, Ismaël

    2013-01-01

    Darwin devised sexual selection theory in order to explain the evolution and maintenance of secondary sexual traits. In mutually ornamented species, however, the broader theoretical framework of social selection is needed. In many cases indeed, understanding the maintenance of mutual ornamentation requires to take into account competition for both sexual (i.e. mates) and non-sexual resources (e.g. food, nest sites). How mutual ornaments maintain and evolve is actually not well understood in s...