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Sample records for 2-cl-phenol durch rhodopseudomonas

  1. Ferrochelatase of Rhodopseudomonas spheroides

    PubMed Central

    Jones, M. S.; Jones, O. T. G.

    1970-01-01

    Extracts of Rhodopseudomonas spheroides contain two ferrochelatases: one is soluble and forms metalloporphyrins from deuteroporphyrin and haematoporphyrin; the other is particulate and forms metalloporphyrins from protoporphyrin, mesoporphyrin, deuteroporphyrin and haematoporphyrin. Neither enzyme incorporates Mg2+ into porphyrins or Fe2+ into porphyrin cytochrome c. By using the particulate enzyme, plots of 1/v versus 1/s when one substrate was varied and the other kept constant showed that neither substrate affected the Km of the other. The suggested sequential mechanism for the reaction is supported by derivative plots of slopes and intercepts. The Km for deuteroporphyrin was 21.3μm and that for Co2+ was 6.13μm. The enzyme incorporated Co2+, Fe2+, Zn2+, Ni2+ and Mn2+; Cd2+ was not incorporated and was an inhibitor, competitive with respect to Co2+, non-competitive with respect to deuteroporphyrin. The Ki for Cd2+ was 0.73μm. Ferrochelatase was inhibited by protohaem, non-competitively with respect to Co2+ or with respect to deuteroporphyrin. Inhibition by magnesium protoporphyrin was non-competitive with respect to deuteroporphyrin, uncompetitive with respect to Co2+. The inhibitory concentrations of the metalloporphyrins are lower than those required for the inhibition of δ-aminolaevulate synthetase by protohaem. Fe2+ is not incorporated aerobically into porphyrins unless an electron donor, succinate or NADH, is supplied; the low aerobic rate of metalloporphyrin synthesis obtained is insensitive to rotenone and antimycin. The rate of Fe3+ incorporation increases as anaerobic conditions are achieved. PMID:5500305

  2. Nitrate reductase from Rhodopseudomonas sphaeroides.

    PubMed Central

    Kerber, N L; Cardenas, J

    1982-01-01

    The facultative phototroph Rhodopseudomonas sphaeroides DSM158 was incapable of either assimilating or dissimilating nitrate, although the organism could reduce it enzymatically to nitrite either anaerobically in the light or aerobically in the dark. Reduction of nitrate was mediated by a nitrate reductase bound to chromatophores that could be easily solubilized and functioned with chemically reduced viologens or photochemically reduced flavins as electron donors. The enzyme was solubilized, and some of its kinetic and molecular parameters were determined. It seemed to be nonadaptive, ammonia did not repress its synthesis, and its activity underwent a rapid decline when the cells entered the stationary growth phase. Studies with inhibitors and with metal antagonists indicated that molybdenum and possibly iron participate in the enzymatic reduction of nitrate. The conjectural significance of this nitrate reductase in phototrophic bacteria is discussed. PMID:6978883

  3. Sulfoacetate generated by Rhodopseudomonas palustris from taurine.

    PubMed

    Denger, Karin; Weinitschke, Sonja; Hollemeyer, Klaus; Cook, Alasdair M

    2004-10-01

    Genes thought to encode (a) the regulator of taurine catabolism under carbon-limiting or nitrogen-limiting conditions and (b) taurine dehydrogenase were found in the genome of Rhodopseudomonas palustris. The organism utilized taurine quantitatively as a sole source of nitrogen (but not of carbon) for aerobic and photoheterotrophic growth. No sulfate was released, and the C-sulfonate bond was recovered stoichiometrically as sulfoacetate, which was identified by mass spectrometry. An inducible sulfoacetaldehyde dehydrogenase was detected. R. palustris thus contains a pathway to generate a natural product that was previously believed to be formed solely from sulfoquinovose.

  4. Electricity generation by Rhodopseudomonas palustris DX-1.

    PubMed

    Xing, Defeng; Zuo, Yi; Cheng, Shaoan; Regan, John M; Logan, Bruce E

    2008-06-01

    Bacteria able to generate electricity in microbial fuel cells (MFCs) are of great interest, but there are few strains capable of high power production in these systems. Here we report that the phototrophic purple nonsulfur bacterium Rhodopseudomonas palustris DX-1, isolated from an MFC, produced electricity at higher power densities (2720 +/- 60 mW/m2) than mixed cultures in the same device. While Rhodopseudomonas species are known for their ability to generate hydrogen, they have not previously been shown to generate power in an MFC, and current was generated without the need for light or hydrogen production. Strain DX-1 utilizes a wide variety of substrates (volatile acids, yeast extract, and thiosulfate) for power production in different metabolic modes, making it highly useful for studying power generation in MFCs and generating power from a range of simple and complex sources of organic matter. These results demonstrate that a phototrophic purple nonsulfur bacterium can efficiently generate electricity by direct electron transfer in MFCs, providing another model microorganism for MFC investigations.

  5. Radiosensibilisierung durch BRAF Inhibitoren.

    PubMed

    Strobel, Sophia Boyoung; Pätzold, Sylvie; Zimmer, Lisa; Jensen, Alexandra; Enk, Alexander; Hassel, Jessica Cecile

    2017-07-01

    In der letzten Zeit wurden in der Literatur vermehrt erhöhte Hauttoxizitäten während einer Kombinationstherapie mit BRAF Inhibitoren und Radiotherapie beschrieben. Wir berichten über sieben Melanompatienten in einem nicht resezierbaren Stadium III oder IV, die eine kombinierte Behandlung aus Bestrahlung und BRAF-Inhibitor erhielten. Bei allen Patienten konnte durch die Kombinationstherapie ein gutes lokales Ansprechen erreicht werden. Nur bei zwei Patienten wurde eine schwere Radiodermatitis (CTCAE Grad 3 bzw. 4) beobachtet. Bei diesen Patienten, die beide Vemurafenib erhielten, trat die Radiodermatitis nach ein bzw. zwei Wochen auf und resultierte in einer Unterbrechung der BRAF-Inhibitor Behandlung.. Die kumulative Dosis bis zum Zeitpunkt der Strahlendermatitis betrug 10 Gy bzw. 35 Gy. Bei allen anderen Vemurafenibpatienten konnten nur milde Reaktionen im Sinne einer Radiodermatitis CTCAE Grad 2, beim Dabrafenibpatienten CTCAE Grade 1 diagnostiziert werden. Bei einem Patienten wurde eine Recalldermatitis nach 14 Tagen einer beendeten Strahlentherapie mit einer kumulativen Dosis von 30 Gy diagnostiziert. Schwere Toxizitätsreaktionen der Haut unter einer BRAF-Inhibitionen treten nicht häufig auf und sind meistens gut therapierbar. Deshalb sollte die Kombinationstherapie bei aggressiv wachsenden Melanomen eine Therapieoption bleiben. Obwohl ein erhöhtes Risiko der Hauttoxizität unter einer Kombinationstherapie von Radiatio und BRAF-Inhibitoren besteht, wird diese von den meisten Patienten gut toleriert. Sequenzielle Therapie anstelle von gleichzeitiger Behandlung scheint die Toxizitätreaktionen nicht zu verhindern. © 2017 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  6. Mapping of Rhodopseudomonas capsulata nif genes.

    PubMed Central

    Wall, J D; Braddock, K

    1984-01-01

    The endogenous gene transfer system of Rhodopseudomonas capsulata was used to analyze mutations which block the ability to use molecular nitrogen as the sole nitrogen source (nif). With this fine-structure mapping tool, linkage of nif mutations could be reliably established if separated by 2,700 base pairs or less. Eleven independent mutations were analyzed, and five linkage groups were found. The overall chromosomal arrangement of these groups awaits conjugational or physical analysis. A candidate for the inactive subunit of R. capsulata Fe protein was located in gels at a position of about 38,000 molecular weight, 5,000 more than that of the presumed active subunit. Images PMID:6586713

  7. Spontaneous Nif- mutants of Rhodopseudomonas capsulata.

    PubMed Central

    Wall, J D; Love, J; Quinn, S P

    1984-01-01

    Revertible, spontaneous Nif- mutants of Rhodopseudomonas capsulata have been shown to accumulate in cultures growing photosynthetically with an amino acid as the nitrogen source such that H2 is maximally produced. The majority of such strains carry mutations which are clustered in a short region of the chromosome, probably representing one or two genes. Because this cluster includes temperature-sensitive mutations, it is also likely that it identifies the structural gene of a polypeptide. The phenotypic characterization of these spontaneous mutants showed (i) an inability to grow with N2 as the nitrogen source, no measurable nitrogenase activity, a reduction or absence of the three polypeptides of the MoFe and Fe proteins of the nitrogenase complex, a faster growth rate on glutamate as the nitrogen source under saturating light, and frequently a small increase in glutamine synthetase activity relative to that of the wild type when grown with glutamate as the nitrogen source. Alterations in other ammonium-assimilatory enzyme activities were not observed. Taken together, these properties suggest that the mutations have affected a regulatory protein necessary for nitrogen fixation. Images PMID:6146598

  8. Functional Annotation Analytics of Rhodopseudomonas palustris Genomes.

    PubMed

    Simmons, Shaneka S; Isokpehi, Raphael D; Brown, Shyretha D; McAllister, Donee L; Hall, Charnia C; McDuffy, Wanaki M; Medley, Tamara L; Udensi, Udensi K; Rajnarayanan, Rajendram V; Ayensu, Wellington K; Cohly, Hari H P

    2011-01-01

    Rhodopseudomonas palustris, a nonsulphur purple photosynthetic bacteria, has been extensively investigated for its metabolic versatility including ability to produce hydrogen gas from sunlight and biomass. The availability of the finished genome sequences of six R. palustris strains (BisA53, BisB18, BisB5, CGA009, HaA2 and TIE-1) combined with online bioinformatics software for integrated analysis presents new opportunities to determine the genomic basis of metabolic versatility and ecological lifestyles of the bacteria species. The purpose of this investigation was to compare the functional annotations available for multiple R. palustris genomes to identify annotations that can be further investigated for strain-specific or uniquely shared phenotypic characteristics. A total of 2,355 protein family Pfam domain annotations were clustered based on presence or absence in the six genomes. The clustering process identified groups of functional annotations including those that could be verified as strain-specific or uniquely shared phenotypes. For example, genes encoding water/glycerol transport were present in the genome sequences of strains CGA009 and BisB5, but absent in strains BisA53, BisB18, HaA2 and TIE-1. Protein structural homology modeling predicted that the two orthologous 240 aa R. palustris aquaporins have water-specific transport function. Based on observations in other microbes, the presence of aquaporin in R. palustris strains may improve freeze tolerance in natural conditions of rapid freezing such as nitrogen fixation at low temperatures where access to liquid water is a limiting factor for nitrogenase activation. In the case of adaptive loss of aquaporin genes, strains may be better adapted to survive in conditions of high-sugar content such as fermentation of biomass for biohydrogen production. Finally, web-based resources were developed to allow for interactive, user-defined selection of the relationship between protein family annotations and the R

  9. Functional Annotation Analytics of Rhodopseudomonas palustris Genomes

    PubMed Central

    Simmons, Shaneka S.; Isokpehi, Raphael D.; Brown, Shyretha D.; McAllister, Donee L.; Hall, Charnia C.; McDuffy, Wanaki M.; Medley, Tamara L.; Udensi, Udensi K.; Rajnarayanan, Rajendram V.; Ayensu, Wellington K.; Cohly, Hari H.P.

    2011-01-01

    Rhodopseudomonas palustris, a nonsulphur purple photosynthetic bacteria, has been extensively investigated for its metabolic versatility including ability to produce hydrogen gas from sunlight and biomass. The availability of the finished genome sequences of six R. palustris strains (BisA53, BisB18, BisB5, CGA009, HaA2 and TIE-1) combined with online bioinformatics software for integrated analysis presents new opportunities to determine the genomic basis of metabolic versatility and ecological lifestyles of the bacteria species. The purpose of this investigation was to compare the functional annotations available for multiple R. palustris genomes to identify annotations that can be further investigated for strain-specific or uniquely shared phenotypic characteristics. A total of 2,355 protein family Pfam domain annotations were clustered based on presence or absence in the six genomes. The clustering process identified groups of functional annotations including those that could be verified as strain-specific or uniquely shared phenotypes. For example, genes encoding water/glycerol transport were present in the genome sequences of strains CGA009 and BisB5, but absent in strains BisA53, BisB18, HaA2 and TIE-1. Protein structural homology modeling predicted that the two orthologous 240 aa R. palustris aquaporins have water-specific transport function. Based on observations in other microbes, the presence of aquaporin in R. palustris strains may improve freeze tolerance in natural conditions of rapid freezing such as nitrogen fixation at low temperatures where access to liquid water is a limiting factor for nitrogenase activation. In the case of adaptive loss of aquaporin genes, strains may be better adapted to survive in conditions of high-sugar content such as fermentation of biomass for biohydrogen production. Finally, web-based resources were developed to allow for interactive, user-defined selection of the relationship between protein family annotations and the R

  10. Reductive Pentose Cycle and Formate Assimilation in Rhodopseudomonas palustris

    PubMed Central

    Stokes, Jean E.; Hoare, Derek S.

    1969-01-01

    Rhodopseudomonas palustris assimilated formate autotrophically as carbon dioxide and hydrogen arising from the activity of the formic hydrogenlyase system. Kinetic analyses of cell suspensions pulse-labeled with 14C-formate or 14C-bicarbonate showed similar distributions of incorporated radioactivity. In both cases phosphate esters were the first assimilation products. Ribulose diphosphate carboxylase, phosphoribose isomerase, and phosphoribulokinase, characteristic enzymes of the reductive pentose cycle, were present in extracts of cells grown on formate. PMID:5354954

  11. The Photosynthetic Reaction Center from the Purple Bacterium Rhodopseudomonas viridis

    NASA Astrophysics Data System (ADS)

    Deisenhofer, Johann; Michel, Hartmut

    1989-09-01

    The history and methods of membrane protein crystallization are described. The solution of the structure of the photosynthetic reaction center from the bacterium Rhodopseudomonas viridis is described, and the structure of this membrane protein complex is correlated with its function as a light-driven electron pump across the photosynthetic membrane. Conclusions about the structure of the photosystem II reaction center from plants are drawn, and aspects of membrane protein structure are discussed.

  12. Biotransformation of Rutin Using Crude Enzyme from Rhodopseudomonas palustris.

    PubMed

    Guan, Chun-Jie; Ji, Yu-Jia; Hu, Jia-Lin; Hu, Chao-Nan; Yang, Fei; Yang, Guan-E

    2017-04-01

    Rhodopseudomonas palustris was selected for the ability to grow in diglycosylated flavonoids-based media, exhibited deglycosylation activity. The present study aimed to investigate the ability of a crude enzyme from Rhodopseudomonas palustris to transform rutin. Our results showed the crude enzyme was found to transform rutin to quercetin via isoquercitrin. The maximum enzyme activities were observed at pH 7.0, 25 °C, and rutin concentration of 1.0 mg mL(- 1). Under optimal conditions, 13.11 μM rutin was biotransformed into 6.86 μM isoquercitrin and 11.64 μM quercetin after 11 and 21 h, respectively. The study demonstrates an eco-friendly and potential economically viable 'green' conversion route to convert rutin to isoquercitrin and quercetin, which is of great interest, considering the therapeutic applications of isoquercitrin and quercetin. The specific biotransformation of rutin to isoquercitrin and quercetin, using the crude enzyme from Rhodopseudomonas palustris, may potentially serve as a new method for industrial production of isoquercitrin and quercetin.

  13. Triazine herbicide resistance in the photosynthetic bacterium Rhodopseudomonas sphaeroides

    PubMed Central

    Brown, Alfred E.; Gilbert, Carl W.; Guy, Rachel; Arntzen, Charles J.

    1984-01-01

    The photoaffinity herbicide azidoatrazine (2-azido-4-ethylamino-6-isopropylamino-s-triazine) selectively labels the L subunit of the reaction center of the photosynthetic bacterium Rhodopseudomonas sphaeroides. Herbicide-resistant mutants retain the L subunit and have altered binding properties for methylthio- and chloro-substituted triazines as well as altered equilibrium constants for electron transfer between primary and secondary electron acceptors. We suggest that a subtle alteration in the L subunit is responsible for herbicide resistance and that the L subunit is the functional analog of the 32-kDa QB protein of chloroplast membranes. Images PMID:16593520

  14. Inorganic nitrogen assimilation by the photosynthetic bacterium Rhodopseudomonas capsulata.

    PubMed Central

    Johansson, B C; Gest, H

    1976-01-01

    The photosynthetic bacterium Rhodopseudomonas capsulata lacks glutamate dehydrogenase and normally uses the glutamine synthetase/glutamate synthase sequence of reactions for assimilation of N2 and ammonia. The glutamine synthetase in cell-free extracts of the organism is completely sedimented by centrifugation at 140,000 X g for 2 h, is inhibited by L-alanine but not by adenosine 5'-monophosphate, and exhibits two apparent Km values for ammonia (ca. 13 muM and 1 mM). PMID:10281

  15. Triazine herbicide resistance in the photosynthetic bacterium Rhodopseudomonas sphaeroides

    SciTech Connect

    Brown, A.E.; Gilbert, C.W.; Guy, R.; Arntzen, C.J.

    1984-10-01

    The photoaffinity herbicide azidoatrazine (2-azido-4-ethylamino-6-isopropylamino-s-triazine) selectively labels the L subunit of the reaction center of the photosynthetic bacterium Rhodopseudomonas sphaeroides. Herbicide-resistant mutants retain the L subunit and have altered binding properties for methylthio- and chloro-substituted triazines as well as altered equilibrium constants for electron transfer between primary and secondary electron acceptors. We suggest that a subtle alteration in the L subunit is responsible for herbicide resistance and that the L subunit is the functional analog of the 32-kDa Q/sub B/ protein of chloroplast membranes. 42 references, 6 figures, 1 table.

  16. Acclimation strategy of Rhodopseudomonas palustris to high light irradiance.

    PubMed

    Muzziotti, Dayana; Adessi, Alessandra; Faraloni, Cecilia; Torzillo, Giuseppe; De Philippis, Roberto

    2017-04-01

    The ability of Rhodopseudomonas palustris cells to rapidly acclimate to high light irradiance is an essential issue when cells are grown under sunlight. The aim of this study was to investigate the photo-acclimation process in Rhodopseudomonas palustris 42OL under different culturing conditions: (i) anaerobic (AnG), (ii) aerobic (AG), and (iii) under H2-producing (HP) conditions both at low (LL) and high light (HL) irradiances. The results obtained clearly showed that the photosynthetic unit was significantly affected by the light irradiance at which Rp. palustris 42OL was grown. The synthesis of carotenoids was affected by both illumination and culturing conditions. At LL, lycopene was the main carotenoid synthetized under all conditions tested, while at HL under HP conditions, it resulted the predominant carotenoid. Oppositely, under AnG and AG at HL, rhodovibrin was the major carotenoid detected. The increase in light intensity produced a deeper variation in light-harvesting complexes (LHC) ratio. These findings are important for understanding the ecological distribution of PNSB in natural environments, mostly characterized by high light intensities, and for its growth outdoors.

  17. Metabolic engineering of Rhodopseudomonas palustris for squalene production.

    PubMed

    Xu, Wen; Chai, Changbin; Shao, Lingqiao; Yao, Jia; Wang, Yang

    2016-05-01

    Squalene is a strong antioxidant used extensively in the food, cosmetic and medicine industries. Rhodopseudomonas palustris TIE-1 was used as the host because of its ability to grow photosynthetically using solar energy and carbon dioxide from atmosphere. The deletion of the shc gene resulted in a squalene production of 3.8 mg/g DCW, which was 27-times higher than that in the wild type strain. For constructing a substrate channel to elevate the conversion efficiency, we tried to fuse crtE gene with hpnD gene. By fusing the two genes, squalene content was increased to 12.6 mg/g DCW, which was 27.4 % higher than that resulted from the co-expression method. At last, the titer of squalene reached 15.8 mg/g DCW by co-expressing the dxs gene, corresponding to 112-fold increase relative to that for wild-type strain. This study provided novel strategies for improving squalene yield and demonstrated the potential of producing squalene by Rhodopseudomonas palustris.

  18. Essential Genome of the Metabolically Versatile Alphaproteobacterium Rhodopseudomonas palustris

    PubMed Central

    Pechter, Kieran B.; Gallagher, Larry; Pyles, Harley; Manoil, Colin S.

    2015-01-01

    ABSTRACT Rhodopseudomonas palustris is an alphaproteobacterium that has served as a model organism for studies of photophosphorylation, regulation of nitrogen fixation, production of hydrogen as a biofuel, and anaerobic degradation of aromatic compounds. This bacterium is able to transition between anaerobic photoautotrophic growth, anaerobic photoheterotrophic growth, and aerobic heterotrophic growth. As a starting point to explore the genetic basis for the metabolic versatility of R. palustris, we used transposon mutagenesis and Tn-seq to identify 552 genes as essential for viability in cells growing aerobically on semirich medium. Of these, 323 have essential gene homologs in the alphaproteobacterium Caulobacter crescentus, and 187 have essential gene homologs in Escherichia coli. There were 24 R. palustris genes that were essential for viability under aerobic growth conditions that have low sequence identity but are likely to be functionally homologous to essential E. coli genes. As expected, certain functional categories of essential genes were highly conserved among the three organisms, including translation, ribosome structure and biogenesis, secretion, and lipid metabolism. R. palustris cells divide by budding in which a sessile cell gives rise to a motile swarmer cell. Conserved cell cycle genes required for this developmental process were essential in both C. crescentus and R. palustris. Our results suggest that despite vast differences in lifestyles, members of the alphaproteobacteria have a common set of essential genes that is specific to this group and distinct from that of gammaproteobacteria like E. coli. IMPORTANCE Essential genes in bacteria and other organisms are those absolutely required for viability. Rhodopseudomonas palustris has served as a model organism for studies of anaerobic aromatic compound degradation, hydrogen gas production, nitrogen fixation, and photosynthesis. We used the technique of Tn-seq to determine the essential genes of

  19. Erweiterung modellbasierter Segmentierung durch lokale Deformationskriterien

    NASA Astrophysics Data System (ADS)

    Erdt, Marius; Tulchiner, Roman; Sakas, Georgios

    Modellbasierte Ansätze sind heutzutage Stand der Technik zur automatischen Organsegmentierung in medizinischen Bilddatensätzen. In dieser Arbeit wird ein Verfahren vorgestellt, welches die modellbasierte Segmentierung durch lokale Deformationskriterien erweitert, um eine bessere lokale Anpassung der Oberflächenmodelle an Bildstrukturen sowohl hoher als auch niedriger Frequenz zu erreichen. Die beschriebene Methode wird anhand von Computer-Tomographie Datensätzen der Niere beschrieben und evaluiert.

  20. Mechanism of nitrogenase switch-off by oxygen. [Klebsiella pneumoniae; Rhodopseudomonas sphaeroides f. sp. denitrificans; Rhodopseudomonas capsulate

    SciTech Connect

    Goldberg, I.; Nadler, V.; Hochman, A.

    1987-02-01

    Oxygen caused a reversible inhibition (switch-off) of nitrogenase activity in whole cells of four strains of diazotrophs, the facultative anaerobe Klebsiella pneumoniae and three strains of photosynthetic bacteria (Rhodopseudomonas sphaeroides f. sp. denitrificans and Rhodopseudomonas capsulata strians AD2 and BK5). In K. pneumoniae 50% inhibition of acetylene reduction was attained at an O/sub 2/ concentration of 0.37 ..mu..M. Cyanide (90 ..mu..M), which did not affect acetylene reduction but inhibited whole-cell respiration by 60 to 70%, shifted the O/sub 2/ concentration that caused 50% inhibition of nitrogenase activity to 2.9 ..mu..M. A mutant strain of K. pneumoniae, strain AH11, has a respiration rate that is 65 to 75% higher than that of the wild type, but is nitrogenase activity is similar to wild-type activity. Acetylene reduction by whole cells of this mutant was inhibited 50% by 0.20 ..mu..M O/sub 2/. Inhibition by CN/sup -/ of 40 to 50% of the O/sub 2/ uptake in the mutant shifted the O/sub 2/ concentration that caused 50% inhibition of nitrogenase to 1.58 ..mu..M. Thus, when the respiration rates were lower, higher oxygen concentrations were required to inhibit nitrogenase. Reversible inhibition of nitrogenase activity in vivo was caused under anaerobic conditions by other electron acceptors. Addition of 2 mM sulfite to cell suspensions of R. capsulata B10 and R. sphaeroides inhibited nitrogenase activity. Nitrite also inhibited acetylene reduction in whole cells of the photodenitrifier R. sphaeroides but not in R. capsulata B10, which is not capable of enzymatic reduction of NO/sub 2//sup -/. Lower concentrations of NO/sub 2//sup -/ were required to inhibit the activity in NO/sub 3//sup -/-grown cells, which have higher activities of nitrite reductase.

  1. Physiology of dark fermentative growth of Rhodopseudomonas capsulata

    SciTech Connect

    Madigan, M.T.; Cox, J.C.; Gest, H.

    1980-06-01

    The photosynthetic bacterium Rhodopseudomonas capsulata can grow under anaerobic conditions with light as the energy source or, alternatively, in darkness with D-fructose or certain other sugars as the sole source of carbon and energy. Growth in the latter mode requires an ''accessory oxidant'' such as trimethylamine-N-oxide, and the resulting cells contain the photosynthetic pigments characteristic of R. capsulata (associated with intracytoplasmic membranes) and substantial deposits of poly-beta-hydroxybutyrate. In dark anaerobic batch cultures in fructose plus trimethylamine-N-oxide medium, trimethylamine formatin parallels growth, and typical fermentation products accumulate, namely, CO2 and formic, acetic, and lactic acids. These products are also found in dark anaerobic continuous cultures of R. capsulata; acetic acid and CO2 predominate when fructose is limiting, whereas formic and lactic acids are observed at elevated concentrations when trimethylamine-N-oxide is the limiting nutrient. Evidence is presented to support the conclusions that ATP generation during anaerobic dark growth of R. capsulata on fructose plus trimethylamine-N-oxide occurs by substrate level phosphorylations associated with classical glycolysis and pyruvate dissimilation, and that the required accessory oxidant functions as an electron sink to permit the management of fermentative redox balance, rather than as a terminal electron acceptor necessary for electron transport-driven phosphorylation.

  2. Biogeography of the purple nonsulfur bacterium Rhodopseudomonas palustris.

    PubMed

    Oda, Yasuhiro; Star, Bastiaan; Huisman, Louis A; Gottschal, Jan C; Forney, Larry J

    2003-09-01

    The biogeography of the purple nonsulfur bacterium Rhodopseudomonas palustris on a local scale was investigated. Thirty clones of phototrophic bacteria were isolated from each of five unevenly spaced sampling locations in freshwater marsh sediments along a linear 10-m transect, and a total of 150 clones were characterized by BOX-PCR genomic DNA fingerprinting. Cluster analysis of 150 genomic fingerprints yielded 26 distinct genotypes, and 106 clones constituted four major genotypes that were repeatedly isolated. Representatives of these four major genotypes were tentatively identified as R. palustris based on phylogentic analyses of 16S rRNA gene sequences. The differences in the genomic fingerprint patterns among the four major genotypes were accompanied by differences in phenotypic characteristics. These phenotypic differences included differences in the kinetics of carbon source use, suggesting that there may be functional differences with possible ecological significance among these clonal linages. Morisita-Horn similarity coefficients (C(MH)), which were used to compare the numbers of common genotypes found at pairs of sampling locations, showed that there was substantial similarity between locations that were 1 cm apart (C(MH), >/=0.95) but there was almost no similarity between locations that were >/=9 m apart (C(MH),

  3. Biogeography of the Purple Nonsulfur Bacterium Rhodopseudomonas palustris

    PubMed Central

    Oda, Yasuhiro; Star, Bastiaan; Huisman, Louis A.; Gottschal, Jan C.; Forney, Larry J.

    2003-01-01

    The biogeography of the purple nonsulfur bacterium Rhodopseudomonas palustris on a local scale was investigated. Thirty clones of phototrophic bacteria were isolated from each of five unevenly spaced sampling locations in freshwater marsh sediments along a linear 10-m transect, and a total of 150 clones were characterized by BOX-PCR genomic DNA fingerprinting. Cluster analysis of 150 genomic fingerprints yielded 26 distinct genotypes, and 106 clones constituted four major genotypes that were repeatedly isolated. Representatives of these four major genotypes were tentatively identified as R. palustris based on phylogentic analyses of 16S rRNA gene sequences. The differences in the genomic fingerprint patterns among the four major genotypes were accompanied by differences in phenotypic characteristics. These phenotypic differences included differences in the kinetics of carbon source use, suggesting that there may be functional differences with possible ecological significance among these clonal linages. Morisita-Horn similarity coefficients (CMH), which were used to compare the numbers of common genotypes found at pairs of sampling locations, showed that there was substantial similarity between locations that were 1 cm apart (CMH, ≥0.95) but there was almost no similarity between locations that were ≥9 m apart (CMH, ≤0.25). These calculations showed there was a gradual decrease in similarity among the five locations as a function of distance and that clones of R. palustris were lognormally distributed along the linear 10-m transect. These data indicate that natural populations of R. palustris are assemblages of genetically distinct ecotypes and that the distribution of each ecotype is patchy. PMID:12957900

  4. Enhancement of growth and yield of tomato by Rhodopseudomonas sp. under greenhouse conditions.

    PubMed

    Lee, Kang-Hyeong; Koh, Rae-Hyun; Song, Hong-Gyu

    2008-12-01

    A greenhouse test was carried out to examine the effects on tomato growth of application of purple non-sulfur bacterium Rhodopseudomonas sp. which had enhanced germination and growth of tomato seed under axenic conditions. The shoot length of tomato plant inoculated by Rhodopseudomonas sp. KL9 increased by 34.6% compared to that of control in 8 weeks of cultivation. During the same period, this strain increased 120.6 and 78.6% of dry weight of shoot and root of tomato plants, respectively. The formation ratio of tomato fruit from flower was also raised by inoculation of KL9. In addition, Rhodopseudomonas sp. KL9 treatment enhanced the fresh weight and lycopene content in the harvested tomato fruits by 98.3 and 48.3%, respectively compared to those of the uninoculated control. When the effect on the indigenous bacterial community and fate of the inoculated Rhodopseudomonas sp. KL9 were monitored by denaturing gradient gel electrophoresis analysis, its application did not affect the native bacterial community in tomato rhizosphere soil, but should be repeated to maintain its population size. This bacterial capability may be applied as an environment-friendly biofertilizer to cultivation of high quality tomato and other crops including lycopene-containing vegetables and fruits.

  5. Development of a gene cloning system for the hydrogen-producing marine photosynthetic bacterium Rhodopseudomonas sp

    SciTech Connect

    Matsunaga, T.; Matsunaga, N.; Tsubaki, K.; Tanaka, T.

    1986-10-01

    Seventy-six strains of marine photosynthetic bacteria were analyzed by agarose gel electrophoresis for plasmid DNA content. Among these strains, 12 carried two to four different plasmids with sizes ranging from 3.1 to 11.0 megadaltons. The marine photosynthetic bacterium Rhodopseudomonas sp. NKPB002106 had two plasmids, pRD06S and pRD06L. The smaller plasmid, pRD06S, had a molecular weight of 3.8 megadaltons and was cut at a single site by restriction endonucleases SalI, SmaI, PstI, XhoI, and BglII. Moreover, the marine photosynthetic bacterium Rhodopseudomonas sp. NKPB002106 containing plasmid pRD06 had a satisfactory growth rate (doubling time, 7.5 h), a hydrogen-producing rate of 0.96 ..mu..mol/mg (dry weight) of cells per h, and nitrogen fixation capability. Plasmid pRD06S, however, had neither drug resistance nor heavy-metal resistance, and its copy number was less than 10. Therefore, a recombinant plasmid consisting of pRD06S and Escherichia coli cloning vector pUC13 was constructed and cloned in E. coli. The recombinant plasmid was transformed into Rhodopseudomonas sp. NKPB002106. As a result, Rhodopseudomonas sp. NKPB002106 developed ampicillin resistance. Thus, a shuttle vector for gene transfer was constructed for marine photosynthetic bacteria.

  6. Metagenome-Assembled Genome Sequence of Rhodopseudomonas palustris Strain ELI 1980, Commercialized as a Biostimulant

    PubMed Central

    Crovadore, Julien; Xu, Shoutao; Chablais, Romain; Cochard, Bastien; Lukito, Delvia; Calmin, Gautier

    2017-01-01

    ABSTRACT We report here the draft genome sequence of strain ELI 1980 of Rhodopseudomonas palustris, commercialized as a biostimulant for agriculture. The genome was reconstructed from the metagenome of a commercial product containing this strain as its major component. PMID:28473374

  7. Rhodopseudomonas telluris sp. nov., a phototrophic alphaproteobacterium isolated from paddy soil.

    PubMed

    Hiraishi, Akira; Okamura, Keiko

    2017-09-01

    A strain of anoxygenic phototrophic bacteria isolated from paddy soil (designated strain TUT3615T) was studied taxonomically in comparison with Rhodopseudomonasstrain ATCC 17005 as its nearest phylogenetic relative. Strains TUT3615T and ATCC 17005 had budding rod-shaped cells and showed in vivo absorption maxima at 804 and 860 nm in the near infrared region, indicating the presence of bacteriochlorophyll a. The intracytoplasmic membrane system was of the lamellar type parallel to the cytoplasmic membrane. 16S rRNA gene sequence comparisons showed that strains TUT3615T and ATCC 17005 had a 99.7 % level of similarity to one another and were closest to Rhodopseudomonas palustris ATCC 17001T (98.6 % similarity) among the established species of the genus Rhodopseudomonas. Genomic DNA-DNA hybridization studies revealed that strains TUT3615T and ATCC 17005 had an average similarity level of 65 % to one another and of less than 40 % to the available type strains of Rhodopseudomonas species. Results of phenotypic studies showed that strains TUT3615T and ATCC 17005 could be differentiated from one another and from any previously described species of Rhodopseudomonas. The G+C contents of the genomic DNA of strain TUT3615T and ATCC 17005 were 66.3 and 66.5 mol%, respectively. Based on these data, we propose the name Rhodopseudomonas telluris sp. nov. for strain TUT3615T. The type strain is TUT3615T (=KCTC 23279T=NBRC 107609T). We suspend a proposal to reclassify strain ATCC 17005 as a novel species or subspecies until a genome-wide analysis provides more definite information on its taxonomic position.

  8. Cyanide reduction by nitrogenase in intact cells of Rhodopseudomonas gelatinose Molisch.

    PubMed

    Materassi, R; Balloni, W; Florenzano, G

    1977-01-01

    Intact cells of Rhodopseudomonas gelatinosa, grown in N-free medium, reduce cyanide to methane and ammonia at a rate 5--8 times lower than acetylene. Cyanide reduction in whole cells is distinctly more sensitive to cyanide inhibition compared with enzyme preparations. These results are discussed in view of the exploitation of nitrogen-fixing photobacteria in the anaerobic detoxification of cyanide-containing wastewaters.

  9. Effects of application of Rhodopseudomonas sp. on seed germination and growth of tomato under axenic conditions.

    PubMed

    Koh, Rae-Hyun; Song, Hong-Gyu

    2007-11-01

    Purple nonsulfur bacteria were isolated from river sediments and their growth promoting capabilities on tomato were examined. Isolated strains KL9 and BL6 were identified as Rhodopseudomonas spp. by 16S rDNA sequence analysis. Rhodopseudomonas strain KL9 maximally produced 5.56 mM/ min/mg protein and 67.2 microM/min/mg protein of indole-3-acetic acid (IAA) and 5-aminolevulinic acid (ALA), respectively, which may be one of the mechanisms of plant growth enhancement. The germination percentage of tomato seed, total length, and dry mass of germinated tomato seedling increased by 30.2%, 71.1%, and 270.8%, respectively, compared with those of the uninoculated control 7 days after inoculation of strain KL9. The lengths of the root and shoot of germinated seedling treated with 3 mM tryptophan, a precursor of IAA, increased by 104.4% and 156.5%, respectively, 7 days after inoculation of strain KL9. Rhodopseudomonas KL9 increased 123.5% and 54% of the root and shoot lengths of germinated seedling, respectively, treated with 15 mM glycine and succinate, precursors of ALA. This plant growth promoting capability of purple nonsulfur bacteria may be a candidate for a biofertilizer in agriculture.

  10. Nitrous oxide reduction by members of the family Rhodospirillaceae and the nitrous oxide reductase of Rhodopseudomonas capsulata

    SciTech Connect

    McEwan, A.G.; Greenfield, A.J.; Wetzstein, H.G.; Jackson, J.B.; Ferguson, S.J.

    1985-11-01

    After growth in the absence of nitrogenous oxides under anaerobic phototrophic conditions, several strains of Rhodopseudomonas capsulata were shown to possess a nitrous oxide reductase activity. The enzyme responsible for this activity had a periplasmic location and resembled a nitrous oxide reductase purified from Pseudomonas perfectomarinus. Electron flow to nitrous oxide reductase was coupled to generation of a membrane potential and inhibited by rotenone but not antimycin. It is suggested that electron flow to nitrous oxide reductase branches at the level of ubiquinone from the previously characterized electron transfer components of R. capsulata. R. capsulata grew under dark anaerobic conditions in the presence of malate as carbon source and nitrous oxide as electron acceptor. This confirms that nitrous oxide respiration is linked to ATP synthesis. Phototrophically and anaerobically grown cultures of nondenitrifying strains of Rhodopseudomonas sphaeroides, Rhodopseudomonas palustris, and Rhodospirillum rubrum also possessed nitrous oxide reductase activity.

  11. Skatole remediation potential of Rhodopseudomonas palustris WKU-KDNS3 isolated from an animal waste lagoon.

    PubMed

    Sharma, N; Doerner, K C; Alok, P C; Choudhary, M

    2015-03-01

    Skatole (3MI) is a major contributor to the malodor emission resulting from ruminant and human faeces. The remediation of malodor has been a major challenge for the animal production industry. In this investigation, a pure culture of purple nonsulphur bacterium capable of degrading 3MI was isolated from a swine waste lagoon using an enrichment technique and identified as Rhodopseudomonas palustris WKU-KDNS3 based on 16S rRNA analysis and UV-visible spectroscopy. The cell structure of the organism was confirmed by transmission electron microscopy. Growth profile and 3MI removal pattern were determined using media supplemented with 0.1 μmol 3MI under short-term and long-term aerobic growth conditions. The organism grew on 3MI media as luxuriantly as control (without 3MI). Growth of R. palustris WKU-KDNS3 demonstrated a significant reduction in the level of 3MI (>48%) in 72 h. The level of 3MI dropped further by >93% of the total concentration present in the medium in 21 days. Skatole remediation potential of R. palustris WKU-KDNS3 can be judiciously utilized in various animal and industrial waste treatment systems. Odour pollution is a serious environmental problem, particularly in the agriculture industry, and technologies based on chemical remediation are less effective and cost prohibitive. In this study, the newly isolated Rhodopseudomonas palustris strain WKU-KDNS3 causes biodegradation of 3-methylindole (skatole), which is one of the most offensive odorants present in wastewater lagoons. Aerobic degradation of this widely spread aromatic pollutant by Rhodopseudomonas strain is a significant finding that enhances the present understanding about metabolic versatility of purple photosynthetic nonsulphur bacteria. The remediation potential of R. palustris WKU-KDNS3 can also be gainfully utilized in various waste treatment facilities. © 2014 The Society for Applied Microbiology.

  12. Isoprenoid hydrocarbons produced by thermal alteration of Nostoc muscorum and Rhodopseudomonas spheroides

    NASA Technical Reports Server (NTRS)

    Philp, R. P.; Brown, S.; Calvin, M.

    1978-01-01

    The potential of algae and photosynthetic bacteria to serve as precursors of kerogen was studied to determine what factors affect the relative rates of formation of precursor hydrocarbons. Cells of Nostoc muscorum and Rhodopseudomonas spheroides were subjected to thermal alteration (by heating samples in glass tubes sealed under nitrogen) for two, four, and twelve weeks. Both unextracted and extracted cells in the absence and presence of montmorillonite were investigated, and the isoprenoid hydrocarbons produced in these experiments were determined. Phytane and five isomeric phytenes were the main hydrocarbons observed; their relative rates of formation in the different experimental conditions are described. No phytadienes, pristane, or pristenes were detected.

  13. Augmentation of H2 photoproduction in Rhodopseudomonas palustris by N-heterocyclic aromatic compounds.

    PubMed

    Archana, A; Sasikala, Ch; Ramana, Ch V

    2003-01-01

    Increases of 23- (5.6 mmol acetylene reduced mg dry wt(-1)) and 16- (4 mmol acetylene reduced mg dry wt(-1)) fold in nitrogenase activity and 12- (671 microl H2 mg dry wt(-1) h(-1)) and 6- (349 microl mg dry wt(-1) h(-1)) fold in H2 photoproduction in Rhodopseudomonas palustris JA1 over 24 h were achieved with pyrazine 2-carboxylate (3 mM) and 3-picoline (3 mM), respectively, and were higher than earlier reports of enhancement (1.5 to 5-fold) in biological H2 production using various alternative methods.

  14. Isoprenoid hydrocarbons produced by thermal alteration of Nostoc muscorum and Rhodopseudomonas spheroides

    NASA Technical Reports Server (NTRS)

    Philp, R. P.; Brown, S.; Calvin, M.

    1978-01-01

    The potential of algae and photosynthetic bacteria to serve as precursors of kerogen was studied to determine what factors affect the relative rates of formation of precursor hydrocarbons. Cells of Nostoc muscorum and Rhodopseudomonas spheroides were subjected to thermal alteration (by heating samples in glass tubes sealed under nitrogen) for two, four, and twelve weeks. Both unextracted and extracted cells in the absence and presence of montmorillonite were investigated, and the isoprenoid hydrocarbons produced in these experiments were determined. Phytane and five isomeric phytenes were the main hydrocarbons observed; their relative rates of formation in the different experimental conditions are described. No phytadienes, pristane, or pristenes were detected.

  15. Draft genome sequence and overview of the purple non sulfur bacterium Rhodopseudomonas palustris 42OL.

    PubMed

    Adessi, Alessandra; Spini, Giulia; Presta, Luana; Mengoni, Alessio; Viti, Carlo; Giovannetti, Luciana; Fani, Renato; De Philippis, Roberto

    2016-01-01

    Rhodopseudomonas palustris strain 42OL was isolated in 1973 from a sugar refinery waste treatment pond. The strain has been prevalently used for hydrogen production processes using a wide variety of waste-derived substrates, and cultured both indoors and outdoors, either freely suspended or immobilized. R. palustris 42OL was suitable for many other applications and capable of growing in very different culturing conditions, revealing a wide metabolic versatility. The analysis of the genome sequence allowed to identify the metabolic pathways for hydrogen and poly-β-hydroxy-butyrate production, and confirmed the ability of using a wide range of organic acids as substrates.

  16. Overproduction of nitrogenase by nitrogen-limited cultures of Rhodopseudomonas palustris.

    PubMed Central

    Arp, D J; Zumft, W G

    1983-01-01

    Rhodopseudomonas palustris cells grown on limiting nitrogen produced four- to eightfold higher nitrogenase specific activity relative to cells sparged with N2. The high activity of N-limited cells was the result of overproduction of the nitrogenase proteins. This was shown by four independent techniques: (i) titration of the Mo-Fe protein in cell-free extracts with Fe protein from Azotobacter vinelandii; (ii) direct detection of the subunits of Mo-Fe protein by sodium dodecyl sulfate-polyacrylamide gel electrophoresis; (iii) monitoring of the electron paramagnetic resonance spectrum of Mo-Fe protein in whole cells; and (iv) immunological assay of the Fe protein level with an antiserum against the homologous protein of Rhodospirillum rubrum. The derepressed level of nitrogenase found in N2-grown cells was not due to an increased turnover of nitrogenase. The apparent half-lives of nitrogenase in N2-grown and N-limited cells were 58 and 98 h, respectively, but were too long to account for the difference in enzyme level. Half-lives were determined by measuring nitrogenase after repression of de novo synthesis by ammonia and subsequent release of nitrogenase switch-off by methionine sulfoximine. Observations were extended to R. rubrum, Rhodopseudomonas capsulata, and Rhodomicrobium vannielii and indicated that overproduction of nitrogenase under nitrogen limitation is not an exceptional property of R. palustris, but rather a general property of phototrophic bacteria. Images PMID:6402491

  17. Purification, crystallization and preliminary crystallographic analysis of cytochrome P450 203A1 from Rhodopseudomonas palustris

    SciTech Connect

    Pang, Xiaoyun; Xu, Feng; Bell, Stephen G.; Guo, Delin; Wong, Luet-Lok; Rao, Zihe

    2007-04-01

    The cytochrome P450 enzyme CYP203A1 from Rhodopseudomonas palustris binds a wide range of highly substituted aromatic compounds and may play an important role in the astonishing metabolic diversity of this organism. Crystals of CYP203A1 that diffract to 2.0 Å resolution have been obtained. Cytochrome P450 enzymes constitute a large family of haemoproteins that catalyze the monooxygenation of a great variety of endogenous and exogenous organic compounds. Cytochrome P450 203A1 (CYP203A1, RPA1009) from the metabolically versatile organism Rhodopseudomonas palustris binds a broad range of substrates, in particular substituted aromatic compounds. Crystals of CYP203A1 suitable for X-ray crystallography have been obtained and diffraction data were collected in-house to 2.0 Å resolution from a single crystal. The crystals belong to space group P222, with unit-cell parameters a = 40.1, b = 95.1, c = 99.0 Å, α = β = γ = 90°. There is one protein molecule per asymmetric unit.

  18. Evolution of low-light adapted peripheral light-harvesting complexes in strains of Rhodopseudomonas palustris.

    PubMed

    Kotecha, Abhay; Georgiou, Theonie; Papiz, Miroslav Z

    2013-03-01

    Purple bacteria have peripheral light-harvesting (PLH) complexes adapted to high-light (LH2) and low-light (LH3, LH4) growth conditions. The latter two have only been fully characterised in Rhodopseudomonas acidophila 7050 and Rhodopseudomonas palustris CGA009, respectively. It is known that LH4 complexes are expressed under the control of two light sensing bacteriophytochromes (BphPs). Recent genomic sequencing of a number of Rps. palustris strains has provided extensive information on PLH genes. We show that both LH3 and LH4 complexes are present in Rps. palustris and have evolved in the same operon controlled by the two adjacent BphPs. Two rare marker genes indicate that a gene cluster CL2, containing LH2 genes and the BphP RpBphP4, was internally transferred within the genome to form a new operon CL1. In CL1, RpBphP4 underwent gene duplication to RpBphP2 and RpBphP3, which evolved to sense light intensity rather than spectral red/far-red intensity ratio. We show that a second LH2 complex was acquired in CL1 belonging to a different PLH clade and these two PLH complexes co-evolved together into LH3 or LH4 complexes. The near-infrared spectra provide additional support for our conclusions on the evolution of PLH complexes based on genomic data.

  19. Hydrogen production by photoreactive nanoporous latex coatings of nongrowing Rhodopseudomonas palustris CGA009.

    PubMed

    Gosse, Jimmy L; Engel, Brian J; Rey, Federico E; Harwood, Caroline S; Scriven, L E; Flickinger, Michael C

    2007-01-01

    Nonuniform light distribution is a fundamental limitation to biological hydrogen production by phototrophic bacteria. Numerous light distribution designs and culture conditions have been developed to reduce self-shading and nonuniform reactivity within bioreactors. In this study, highly concentrated (2.0 x 108 CFU/muL formulation) nongrowing Rhodopseudomonas palustris CGA009 were immobilized in thin, nanoporous, latex coatings. The coatings were used to study hydrogen production in an argon atmosphere as a function of coating composition, thickness, and light intensity. These coatings can be generated aerobically or anaerobically and are more reactive than an equivalent number of suspended or settled cells. Rhodopseudomonas palustris latex coatings remained active after hydrated storage for greater than 3 months in the dark and over 1 year when stored at -80 degrees C. The initial hydrogen production rate of the microphotobioreactors containing 6.25 cm2, 58.4 mum thick Rps. palustris latex coatings illuminated by 34.1 PAR mumol photons m-2 s-1 was 6.3 mmol H2 m-2 h-1 and had a final yield of 0.55 mol H2 m-2 in 120 h. A dispersible latex blend has been developed for direct comparison of the specific activity of settled, suspended, and immobilized Rps. palustris.

  20. Arsenic-Redox Transformation and Plant Growth Promotion by Purple Nonsulfur Bacteria Rhodopseudomonas palustris CS2 and Rhodopseudomonas faecalis SS5.

    PubMed

    Batool, Kanza; Tuz Zahra, Fatima; Rehman, Yasir

    2017-01-01

    Arsenic (As) is a well-known toxic metalloid found naturally and released by different industries, especially in developing countries. Purple nonsulfur bacteria (PNSB) are known for wastewater treatment and plant growth promoting abilities. As-resistant PNSB were isolated from a fish pond. Based on As-resistance and plant growth promoting attributes, 2 isolates CS2 and SS5 were selected and identified as Rhodopseudomonas palustris and Rhodopseudomonas faecalis, respectively, through 16S rRNA gene sequencing. Maximum As(V) resistance shown by R. faecalis SS5 and R. palustris CS2 was up to 150 and 100 mM, respectively. R. palustris CS2 showed highest As(V) reduction up to 62.9% (6.29 ± 0.24 mM), while R. faecalis SS5 showed maximum As(III) oxidation up to 96% (4.8 ± 0.32 mM), respectively. Highest auxin production was observed by R. palustris CS2 and R. faecalis SS, up to 77.18 ± 3.7 and 76.67 ± 2.8 μg mL(-1), respectively. Effects of these PNSB were tested on the growth of Vigna mungo plants. A statistically significant increase in growth was observed in plants inoculated with isolates compared to uninoculated plants, both in presence and in absence of As. R. palustris CS2 treated plants showed 17% (28.1 ± 0.87 cm) increase in shoot length and 21.7% (7.07 ± 0.42 cm) increase in root length, whereas R. faecalis SS5 treated plants showed 12.8% (27.09 ± 0.81 cm) increase in shoot length and 18.8% (6.9 ± 0.34 cm) increase in root length as compared to the control plants. In presence of As, R. palustris CS2 increased shoot length up to 26.3% (21.0 ± 1.1 cm), while root length increased up to 31.3% (5.3 ± 0.4 cm), whereas R. faecalis SS5 inoculated plants showed 25% (20.7 ± 1.4 cm) increase in shoot length and 33.3% (5.4 ± 0.65 cm) increase in root length as compared to the control plants. Bacteria with such diverse abilities could be ideal for plant growth promotion in As-contaminated sites.

  1. Arsenic-Redox Transformation and Plant Growth Promotion by Purple Nonsulfur Bacteria Rhodopseudomonas palustris CS2 and Rhodopseudomonas faecalis SS5

    PubMed Central

    Batool, Kanza; tuz Zahra, Fatima

    2017-01-01

    Arsenic (As) is a well-known toxic metalloid found naturally and released by different industries, especially in developing countries. Purple nonsulfur bacteria (PNSB) are known for wastewater treatment and plant growth promoting abilities. As-resistant PNSB were isolated from a fish pond. Based on As-resistance and plant growth promoting attributes, 2 isolates CS2 and SS5 were selected and identified as Rhodopseudomonas palustris and Rhodopseudomonas faecalis, respectively, through 16S rRNA gene sequencing. Maximum As(V) resistance shown by R. faecalis SS5 and R. palustris CS2 was up to 150 and 100 mM, respectively. R. palustris CS2 showed highest As(V) reduction up to 62.9% (6.29 ± 0.24 mM), while R. faecalis SS5 showed maximum As(III) oxidation up to 96% (4.8 ± 0.32 mM), respectively. Highest auxin production was observed by R. palustris CS2 and R. faecalis SS, up to 77.18 ± 3.7 and 76.67 ± 2.8 μg mL−1, respectively. Effects of these PNSB were tested on the growth of Vigna mungo plants. A statistically significant increase in growth was observed in plants inoculated with isolates compared to uninoculated plants, both in presence and in absence of As. R. palustris CS2 treated plants showed 17% (28.1 ± 0.87 cm) increase in shoot length and 21.7% (7.07 ± 0.42 cm) increase in root length, whereas R. faecalis SS5 treated plants showed 12.8% (27.09 ± 0.81 cm) increase in shoot length and 18.8% (6.9 ± 0.34 cm) increase in root length as compared to the control plants. In presence of As, R. palustris CS2 increased shoot length up to 26.3% (21.0 ± 1.1 cm), while root length increased up to 31.3% (5.3 ± 0.4 cm), whereas R. faecalis SS5 inoculated plants showed 25% (20.7 ± 1.4 cm) increase in shoot length and 33.3% (5.4 ± 0.65 cm) increase in root length as compared to the control plants. Bacteria with such diverse abilities could be ideal for plant growth promotion in As-contaminated sites. PMID:28386559

  2. The metabolism of aromatic compounds by Rhodopseudomonas palustris. A new, reductive, method of aromatic ring metabolism

    PubMed Central

    Dutton, P. L.; Evans, W. C.

    1969-01-01

    1. Rhodopseudomonas palustris grows both aerobically and photosynthetically on aromatic acids. p-Hydroxybenzoate and protocatechuate are able to support aerobic growth; these compounds are metabolized by the protocatechuate 4,5-oxygenase pathway. 2. The photoassimilation of benzoate and hydroxybenzoates and the effects of air and darkness on the photoassimilation of benzoate are described. 3. Evidence in conflict with the pathway previously proposed for the photometabolism of benzoate is discussed. 4. The photometabolism of benzoate is accomplished by a novel reductive pathway involving its reduction to cyclohex-1-ene-1-carboxylate, followed by hydration to 2-hydroxycyclohexanecarboxylate and after dehydrogenation to 2-oxocyclohexanecarboxylate further hydration results in ring-fission and the production of pimelate. 5. Attempts were made to prepare cell-free extracts capable of dissimilating benzoate. PMID:5807211

  3. Photosynthetic bacterium Rhodopseudomonas palustris GJ-22 induces systemic resistance against viruses.

    PubMed

    Su, Pin; Tan, Xinqiu; Li, Chenggang; Zhang, Deyong; Cheng, Ju'e; Zhang, Songbai; Zhou, Xuguo; Yan, Qingpin; Peng, Jing; Zhang, Zhuo; Liu, Yong; Lu, Xiangyang

    2017-03-14

    Photosynthetic bacteria (PSB) have been extensively used in agriculture to promote plant growth and to improve crop quality. Their potential application in plant disease management, however, is largely overlooked. In this study, the PSB strain Rhodopseudomonas palustris GJ-22 was investigated for its ability to induce resistance against a plant virus while promoting plant growth. In the field, a foliar spray of GJ-22 suspension protected tobacco plants against tobacco mosaic virus (TMV). Under axenic conditions, GJ-22 colonized the plant phyllosphere and induced resistance against TMV. Additionally, GJ-22 produced two phytohormones, indole-3-acetic acid and 5-aminolevulinic acid, which promote growth and germination in tobacco. Furthermore, GJ-22-inoculated plants elevated their immune response under subsequent TMV infection. This research may give rise to a novel biological agent with a dual function in disease management while promoting plant growth.

  4. Uranium interaction with two multi-resistant environmental bacteria: Cupriavidus metallidurans CH34 and Rhodopseudomonas palustris.

    PubMed

    Llorens, Isabelle; Untereiner, Guillaume; Jaillard, Danielle; Gouget, Barbara; Chapon, Virginie; Carriere, Marie

    2012-01-01

    Depending on speciation, U environmental contamination may be spread through the environment or inversely restrained to a limited area. Induction of U precipitation via biogenic or non-biogenic processes would reduce the dissemination of U contamination. To this aim U oxidation/reduction processes triggered by bacteria are presently intensively studied. Using X-ray absorption analysis, we describe in the present article the ability of Cupriavidus metallidurans CH34 and Rhodopseudomonas palustris, highly resistant to a variety of metals and metalloids or to organic pollutants, to withstand high concentrations of U and to immobilize it either through biosorption or through reduction to non-uraninite U(IV)-phosphate or U(IV)-carboxylate compounds. These bacterial strains are thus good candidates for U bioremediation strategies, particularly in the context of multi-pollutant or mixed-waste contaminations.

  5. Cytochrome P450 enzymes from the metabolically diverse bacterium Rhodopseudomonas palustris

    SciTech Connect

    Bell, Stephen G. . E-mail: stephen.bell@chem.ox.ac.uk; Hoskins, Nicola; Xu Feng; Caprotti, Domenico; Rao Zihe; Wong, L.-L. . E-mail: luet.wong@chem.ox.ac.uk

    2006-03-31

    Four (CYP195A2, CYP199A2, CYP203A1, and CYP153A5) of the seven P450 enzymes, and palustrisredoxin A, a ferredoxin associated with CYP199A2, from the metabolically diverse bacterium Rhodopseudomonas palustris have been expressed and purified. A range of substituted benzenes, phenols, benzaldehydes, and benzoic acids was shown to bind to the four P450 enzymes. Monooxygenase activity of CYP199A2 was reconstituted with palustrisredoxin A and putidaredoxin reductase of the P450cam system from Pseudomonas putida. We found that 4-ethylbenzoate and 4-methoxybenzoate were oxidized to single products, and 4-methoxybenzoate was demethylated to form 4-hydroxybenzoate. Crystals of substrate-free CYP199A2 which diffracted to {approx}2.0 A have been obtained.

  6. Uranium Interaction with Two Multi-Resistant Environmental Bacteria: Cupriavidus metallidurans CH34 and Rhodopseudomonas palustris

    PubMed Central

    Llorens, Isabelle; Untereiner, Guillaume; Jaillard, Danielle; Gouget, Barbara; Chapon, Virginie; Carriere, Marie

    2012-01-01

    Depending on speciation, U environmental contamination may be spread through the environment or inversely restrained to a limited area. Induction of U precipitation via biogenic or non-biogenic processes would reduce the dissemination of U contamination. To this aim U oxidation/reduction processes triggered by bacteria are presently intensively studied. Using X-ray absorption analysis, we describe in the present article the ability of Cupriavidus metallidurans CH34 and Rhodopseudomonas palustris, highly resistant to a variety of metals and metalloids or to organic pollutants, to withstand high concentrations of U and to immobilize it either through biosorption or through reduction to non-uraninite U(IV)-phosphate or U(IV)-carboxylate compounds. These bacterial strains are thus good candidates for U bioremediation strategies, particularly in the context of multi-pollutant or mixed-waste contaminations. PMID:23251623

  7. Complete genome sequence of the metabolically versatile photosynthetic bacterium Rhodopseudomonas palustris

    SciTech Connect

    Larimer, Frank W; Chain, Patrick S. G.; Hauser, Loren John; Lamerdin, Jane; Malfatti, Stephanie; Do, Long; Land, Miriam L; Pelletier, Dale A; Beatty, Thomas; Lang, Andrew S.; Tabita, F Robert; Gibson, Janet L.; Hanson, Thomas E.; Bobst, Cedric; Torres y Torres, Janelle L.; Peres, Caroline; Harrison, Faith H.; Gibson, Jane; Harwood, Caroline S

    2004-01-01

    Rhodopseudomonas palustris is among the most metabolically versatile bacteria known. It uses light, inorganic compounds, or organic compounds, for energy. It acquires carbon from many types of green plant-derived compounds or by carbon dioxide fixation, and it fixes nitrogen. Here we describe the genome sequence of R. palustris, which consists of a 5,459,213-base-pair (bp) circular chromosome with 4,836 predicted genes and a plasmid of 8,427 bp. The sequence reveals genes that confer a remarkably large number of options within a given type of metabolism, including three nitrogenases, five benzene ring cleavage pathways and four light harvesting 2 systems. R. palustris encodes 63 signal transduction histidine kinases and 79 response regulator receiver domains. Almost 15% of the genome is devoted to transport. This genome sequence is a starting point to use R. palustris as a model to explore how organisms integrate metabolic modules in response to environmental perturbations.

  8. Reductive dehalogenation of halocarboxylic acids by the phototrophic genera Rhodospirillum and Rhodopseudomonas.

    PubMed Central

    McGrath, J E; Harfoot, C G

    1997-01-01

    Type strains of the purple nonsulfur species Rhodospirillum rubrum, Rhodospirillum photometricum, and Rhodopseudomonas palustris grew phototrophically on a number of two- and three-carbon halocarboxylic acids in the presence of CO2, by reductive dehalogenation and assimilation of the resulting acid. Strains of each of these species were able to grow on chloroacetic, 2-bromopropionic, 2-chloropropionic, and 3-chloropropionic acids at a concentration of 2 mM. Only R. palustris DSM 123 was able to grow on bromoacetic acid and then only at a reduced concentration of 1 mM. R. palustris ATCC 33872 (formerly R. rutila) was unable to grow on any of the substrates tested. The ability of these organisms to utilize halocarboxylic acids indicates that they may have a significant role to play in the removal of these environmental pollutants from illuminated anaerobic habitats such as lakes, waste lagoons, sediments of ditches and ponds, mud, and moist soil. PMID:9251226

  9. Biohydrogen production from CO-rich syngas via a locally isolated Rhodopseudomonas palustris PT.

    PubMed

    Pakpour, Fatemeh; Najafpour, Ghasem; Tabatabaei, Meisam; Tohidfar, Masoud; Younesi, Habiboallah

    2014-05-01

    Biohydrogen production through water–gas shift (WGS) reaction by a biocatalyst was conducted in batch fermentation. The isolated photosynthetic bacterium Rhodopseudomonas palustris PT was able to utilize carbon monoxide and simultaneously produce hydrogen. Light exposure was provided as an indispensable requirement for the first stage of bacterial growth, but throughout the hydrogen production stage, the energy requirement was met through the WGS reaction. At ambient pressure and temperature, the effect of various sodium acetate concentrations in presence of CO-rich syngas on cell growth, carbon monoxide consumption, and biohydrogen production was also investigated. Maximal efficiency of hydrogen production in response to carbon monoxide consumption was recorded at 86 % and the highest concentration of hydrogen at 33.5 mmol/l was achieved with sodium acetate concentration of 1.5 g/l. The obtained results proved that the local isolate; R. palustris PT, was able to utilize CO-rich syngas and generate biohydrogen via WGS reaction.

  10. Fluorescence blinking of the RC-LH1 complex from Rhodopseudomonas palustris.

    PubMed

    Unterkofler, Sarah; Pflock, Tobias; Southall, June; Cogdell, Richard J; Köhler, Jürgen

    2011-02-25

    We investigate fluorescence blinking of individual RC-LH1 (reaction-centre-light-harvesting 1) complexes from the photosynthetic purple bacterium Rhodopseudomonas palustris. For both the on- and off-periods the telegraph-like intermittency of the fluorescence intensity follows power-law statistics with exponents between 1 and 2. Yet, this behaviour was only observed for a small fraction of the complexes studied. We argue that the majority of the complexes reside in a prolonged on-state, due to a mechanism that is similar to the Coulomb blockade in semiconductor quantum dots, and which results here from the photoinduced charges located within the RC upon photoexcitation of the LH1 antenna. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Light-enhanced bioaccumulation of molybdenum by nitrogen-deprived recombinant anoxygenic photosynthetic bacterium Rhodopseudomonas palustris.

    PubMed

    Naito, Taki; Sachuronggui; Ueki, Masayoshi; Maeda, Isamu

    2016-01-01

    As molybdenum (Mo) is an indispensable metal for plant nitrogen metabolisms, accumulation of dissolved Mo into bacterial cells may connect to the development of bacterial fertilizers that promote plant growth. In order to enhance Mo bioaccumulation, nitrogen removal and light illumination were examined in anoxygenic photosynthetic bacteria (APB) because APB possess Mo nitrogenase whose synthesis is strictly regulated by ammonium ion concentration. In addition, an APB, Rhodopseudomonas palustris, transformed with a gene encoding Mo-responsive transcriptional regulator ModE was constructed. Mo content was most markedly enhanced by the removal of ammonium ion from medium and light illumination while their effects on other metal contents were limited. Increases in contents of trace metals including Mo by the genetic modification were observed. Thus, these results demonstrated an effective way to enrich Mo in the bacterial cells by the culture conditions and genetic modification.

  12. Tn5. 7 construction and physical mapping of pRPS404 containing photosynthetic genes from Rhodopseudomonas capsulata

    SciTech Connect

    Zsebo, K.M.; Wu, F.; Hearst J.E.

    1984-01-01

    A transposon, Tn5.7, has been constructed incorporating the transposition functions of Tn5 and the antibiotic-resistance factors from Tn7. It was used to mutagenize the plasmid pRPS404 which contains the photosynthetic genes of Rhodopseudomonas capsulata and is Kanamycin. In conjunction with the mutagenesis, physical mapping of the restriction endonuclease recognition sites for XhoI. Bg/II, KnpI, and SstI has been accomplished. 13 references, 2 figures.

  13. Regulation of nitrogenase in the photosynthetic bacterium Rhodopseudomonas capsulata as studied by two-dimensional gel electrophoresis.

    PubMed Central

    Hallenbeck, P C; Meyer, C M; Vignais, P M

    1982-01-01

    By using two-dimensional electrophoresis, five putative soluble nif gene products were identified, and the regulation of nif gene expression in Rhodopseudomonas capsulata was investigated. Expression of nif was repressed by ammonia and atmospheric concentrations of oxygen. Deprivation of molybdenum caused an interesting pattern of partial repression of nif gene expression that was not relieved by tungsten. These results are discussed in relation to the better understood system of nif regulation in Klebsiella pneumoniae. Images PMID:6955301

  14. Construction of a genetically engineered microorganism for CO2 fixation using a Rhodopseudomonas/Escherichia coli shuttle vector.

    PubMed

    Du, Cuihong; Zhou, Jiti; Wang, Jing; Yan, Bin; Lu, Hong; Hou, Hongman

    2003-08-08

    The CO2 fixation ability of Rhodopseudomonas palustris DH was enhanced by introducing the recombinant plasmid pMG-CBBM containing the form II ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) gene (cbbM) isolated from Rps. palustris NO. 7. Sequencing of a 3.0-kb PstI fragment containing the cbbM gene revealed an open reading frame encoding 461 amino acids, homologous to known cbbM genes, with a ribosome binding site upstream of cbbM and a terminator downstream of cbbM, without promoter. pMG-CBBM, a Rhodopseudomonas/Escherichia coli shuttle expression plasmid, was derived from the Rhodopseudomonas/E. coli shuttle cloning vector pMG105, by inserting the promoter of the pckA gene and the cbbM gene into its multiple cloning site. Plasmid pMG-CBBM was transformed into Rps. palustris DH by electroporation, and was stably maintained when transformants were grown either photoheterotrophically or photolithoautotrophically in the absence of antibiotics. This is the first report of an expression plasmid containing a Rps. palustris-specific promoter that allows stable expression of a foreign gene in the absence of antibiotic selection.

  15. Bacteria of the genus Rhodopseudomonas (Bradyrhizobiaceae): obligate symbionts in mycelial cultures of the black truffles Tuber melanosporum and Tuber brumale.

    PubMed

    Le Roux, Christine; Tournier, Estelle; Lies, Adrien; Sanguin, Hervé; Chevalier, Gérard; Duponnois, Robin; Mousain, Daniel; Prin, Yves

    2016-01-01

    This work aimed at characterizing 12 isolates of the genus Tuber including Tuber melanosporum (11 isolates) and Tuber brumale (one isolate). This was done using internal transcribed spacer (ITS) sequences, confirming their origin. Analysis of their mating type revealed that both MAT1-1 and MAT1-2 exist within these isolates (with 3 and 8 of each, respectively). We observed that each of these cultures was consistently associated with one bacterium that was intimately linked to fungal growth. These bacterial associates failed to grow in the absence of fungus. We extracted DNA from bacterial colonies in the margin of mycelium and sequenced a nearly complete 16S rDNA gene and a partial ITS fragment. We found they all belonged to the genus Rhodopseudomonas, fitting within different phylogenetic clusters. No relationships were evidenced between bacterial and fungal strains or mating types. Rhodopseudomonas being a sister genus to Bradyrhizobium, we tested the nodulation ability of these bacteria on a promiscuously nodulating legume (Acacia mangium), without success. We failed to identify any nifH genes among these isolates, using two different sets of primers. While the mechanisms of interaction between Tuber and Rhodopseudomonas remain to be elucidated, their interdependency for in vitro growth seems a novel feature of this fungus.

  16. Datenkompression, Prozessoptimierung, Aerodynamik: Eine Tour Durch die Skalen

    NASA Astrophysics Data System (ADS)

    Dahmen, Wolfgang; Marquardt, Wolfgang

    Enorm gestiegene Rechnerkapazitäten ermutigen zu einer immer genaueren Erschließung komplexer Prozesse in Natur- und Ingenieurwissenschaften durch numerische Simulation. Die Mathematik als Schnittstelle zwischen realer und digitaler Welt liefert einerseits die Grundlagen zur Formulierung notwendigerweise vereinfachter Modelle der Realität. Andererseits bietet sie aber auch die methodischen Grundlagen für den Entwurf effizienter Algorithmen, die aus solchen Modellen quantitative Information gewinnen können. Eine zentrale Herausforderung liegt dabei in der Tatsache, dass reale Prozesse meist durch relevante Anteile auf einer riesigen Spannweite von Längenskalen getrieben werden. Die Entwicklung mathematischer Methoden zur Behandlung von Mehrskaligkeit ist daher von wesentlicher Bedeutung. In diesem Artikel wird dies anhand jüngster Entwicklungen in ganz unterschiedlichen Anwendungsbereichen erklärt und illustriert, auch um deutlich zu machen, wieviele "Fliegen“ man mit einer "mathematischen Klappe“ schlagen kann. Insbesondere werden grundlegende, auf Waveletzerlegung beruhende Prinzipien zunächst im Rahmen der Bildkompression und -kodierung auf weitgehend elementare Weise erklärt. Es wird dann aufgezeigt, dass diese Konzepte in ganz ähnlicher Weise bei der Datenanalyse im Zusammenhang mit verfahrenstechnischen Anwendungen, bei großskaligen Optimierungsproblemen der Prozessindustrie sowie bei komplexen Strömungsproblemen wie in aerodynamischen Anwendungen zum Tragen kommen. Stabile Zerlegungen in Anteile unterschiedlicher Längenskalen eröffnen dabei einen Zugang zu adaptiven Lösungskonzepten, die in der Lage sind, automatisch Rechnerresourcen dort zu plazieren, wo sie zu einer ökonomischen Realisierung der gewünschten Lösungsqualität, etwa in Form von Genauigkeitstoleranzen, benötigt werden.

  17. Comparative studies of two membrane fractions isolated from chemotrophically and phototrophically grown cells of Rhodopseudomonas capsulata.

    PubMed Central

    Garcia, A F; Drews, G; Reidl, H H

    1981-01-01

    Light and heavy membrane fractions have been isolated by equilibrium sucrose density centrifugation from Rhodopseudomonas capsulata 938 GCM grown aerobically in the dark (chemotrophically) and anaerobically in the light (phototrophically). The densities of the light and heavy fractions from phototrophic cells were 1.1004 to 1.1006 and 1.1478, respectively, and the densities of the light and heavy fractions from chemotrophic cells were 1.0957 to 1.0958 and 1.1315, respectively. Both fractions were active in photochemical and respiratory functions and in electron transport-coupled phosphorylation. The light membrane fraction isolated from chemotrophic cells contained the reaction center and the light-harvesting pigment-protein complex B 870, but not the variable light-harvesting complex B 800-850. A small amount of the complex B 800-850 was present in the light fraction isolated from phototrophically grown cells, but it was not energetically coupled to the photosynthetic apparatus. From inhibitor studies, difference spectroscopy, and measurement of enzyme activities it was tentatively concluded that the light membrane fraction contains only the reduced nicotinamide adenine dinucleotide-oxidizing electron transport chain having a KCN-insensitive, low-potential cytochrome c oxidase, whereas the heavy fraction contains additionally the succinate dehydrogenase and a high-potential cytochrome b terminal oxidase sensitive to KCN. The light membrane fraction was more labile than the heavy fraction in terms of phosphorylating activity. PMID:7204341

  18. Anaerobic and aerobic metabolism of diverse aromatic compounds by the photosynthetic bacterium Rhodopseudomonas palustris.

    PubMed Central

    Harwood, C S; Gibson, J

    1988-01-01

    The purple nonsulfur photosynthetic bacterium Rhodopseudomonas palustris used diverse aromatic compounds for growth under anaerobic and aerobic conditions. Many phenolic, dihydroxylated, and methoxylated aromatic acids, as well as aromatic aldehydes and hydroaromatic acids, supported growth of strain CGA001 in both the presence and absence of oxygen. Some compounds were metabolized under only aerobic or under only anaerobic conditions. Two other strains, CGC023 and CGD052, had similar anaerobic substrate utilization patterns, but CGD052 was able to use a slightly larger number of compounds for growth. These results show that R. palustris is far more versatile in terms of aromatic degradation than had been previously demonstrated. A mutant (CGA033) blocked in aerobic aromatic metabolism remained wild type with respect to anaerobic degradative abilities, indicating that separate metabolic pathways mediate aerobic and anaerobic breakdown of diverse aromatics. Another mutant (CGA047) was unable to grow anaerobically on either benzoate or 4-hydroxybenzoate, and these compounds accumulated in growth media when cells were grown on more complex aromatic compounds. This indicates that R. palustris has two major anaerobic routes for aromatic ring fission, one that passes through benzoate and one that passes through 4-hydroxybenzoate. Images PMID:3377491

  19. Growth performance and meat quality of broiler chickens supplemented with Rhodopseudomonas palustris in drinking water.

    PubMed

    Xu, Q Q; Yan, H; Liu, X L; Lv, L; Yin, C H; Wang, P

    2014-01-01

    1. The effect of the bacterium, Rhodopseudomonas palustris, on the growth performance and meat quality of broiler chickens was investigated. 2. A total of 900-d-old Arbor Acres broilers were allocated to three experimental treatments for 6 weeks. Chicks were administered with R. palustris in drinking water as follows: (i) control group without R. palustris; (ii) treatment 1 (R1) with R. palustris of 8 × 10(9) cells per chick per day in drinking water; (iii) treatment 2 (R2) with R. palustris of 1.6 × 10(10) cells per chick per day in drinking water. 3. The results showed that, compared with that of control, both groups of R. palustris treatment increased daily weight gain and improved feed conversion ratio of broiler chickens significantly during the whole growing period of 6 weeks. 4. Both total and glutamic acid contents of chicken breast fillet in R. palustris treatment R2 were higher, while the fat content was lower, than those of the control group. Furthermore, R. palustris treatments also improved sensory attributes of chicken breast fillet. 5. As a probiotic providing rich nutrients and biological active substances, R. palustris administration in drinking water displayed a growth promoting effect and improved meat quality of broiler chickens.

  20. Role of proton motive force in phototactic and aerotactic responses of Rhodopseudomonas sphaeroides

    SciTech Connect

    Armitage, J.P.; Ingham, C.; Evans, M.C.W.

    1985-03-01

    Rhodopseudomonas sphaeroides grown under nonrigorous anaerobic conditions in the light developed components of a branched respiratory electron transfer chain, and a photosynthetic electron transfer chain. Both respiratory pathways were sensitive to rotenone and high concentrations of cyanide, but oxygen uptake was only partially inhibited by the addition of low concentrations of cyanide or antimycin A. When incubated anaerobically in the dark, R. sphaeroides responded positively to an oxygen gradient in the absence of rotenone. In the presence of rotenone, aerotaxis only occurred when the antimycin A-sensitive branch of the pathway was functioning, although both branches still reduced oxygen. Although there was electron movement along the respiratory chain, aerotaxis only occurred in response to a change in proton motive force. When incubated anaerobically in the light, the movement of R. sphaeroides up to a light gradient depended on photosynthetic electron transport. When incubated aerobically, high-intensity actinic illumination inhibited oxygen uptake and aerotaxis. In a low-intensity light gradient the phototactic response was inhibited by oxygen. These results are discussed in relation to the interaction of the electron transfer chains and their roles in controlling tactic responses in R. sphaeroides.

  1. Experimental and Computational Investigation of Biofilm Formation by Rhodopseudomonas palustris Growth under Two Metabolic Modes

    PubMed Central

    Kernan, Chase; Chow, Philicia P.; Christianson, Rebecca J.; Huang, Jean

    2015-01-01

    We examined biofilms formed by the metabolically versatile bacterium Rhodopseudomonas palustris grown via different metabolic modes. R. palustris was grown in flow cell chambers with identical medium conditions either in the presence or absence of light and oxygen. In the absence of oxygen and the presence of light, R. palustris grew and formed biofilms photoheterotrophically, and in the presence of oxygen and the absence of light, R. palustris grew and formed biofilms heterotrophically. We used confocal laser scanning microscopy and image analysis software to quantitatively analyze and compare R. palustris biofilm formation over time in these two metabolic modes. We describe quantifiable differences in structure between the biofilms formed by the bacterium grown heterotrophically and those grown photoheterotrophically. We developed a computational model to explore ways in which biotic and abiotic parameters could drive the observed biofilm architectures, as well as a random-forest machine-learning algorithm based on structural differences that was able to identify growth conditions from the confocal imaging of the biofilms with 87% accuracy. Insight into the structure of phototrophic biofilms and conditions that influence biofilm formation is relevant for understanding the generation of biofilm structures with different properties, and for optimizing applications with phototrophic bacteria growing in the biofilm state. PMID:26087200

  2. Kinetic analysis of N-acylphosphatidylserine accumulation and implications for membrane assembly in Rhodopseudomonas sphaeroides.

    PubMed Central

    Cain, B D; Donohue, T J; Kaplan, S

    1982-01-01

    The accumulation of N-acylphosphatidylserine (NAPS) in response to the inclusion of Tris in the growth medium of Rhodopseudomonas sphaeroides strain M29-5 has been examined. In the accompanying paper (Donohue et al., J. Bacteriol. 152:000--000, 1982), we show that in response to Tris, NAPS accumulated to as much as 40% of the total cellular phospholipid content. NAPS accumulation began immediately upon addition of Tris and was reflected as an abrupt 12-fold increase in the apparent rate of NAPS accumulation. We suggest that Tris altered the flow of metabolites through a preexisting and previously unknown metabolic pathway. NAPS accumulation ceased immediately upon the removal of Tris; however, accumulated NAPS remained largely metabolically stable. Importantly, under conditions in which NAPS was not accumulated, the intracytoplasmic membrane was shown to be virtually devoid of newly synthesized NAPS. The significance of this observation is discussed in terms of its physiological implications on phospholipid transfer and membrane biogenesis in R. sphaeroides. PMID:6982265

  3. Enhancement of photohydrogen production using phbC deficient mutant Rhodopseudomonas palustris strain M23.

    PubMed

    Yang, Chu-Fang; Lee, Chi-Mei

    2011-05-01

    This study used a DNA recombination method to knock out the poly-β-hydroxybutyrate (PHB) synthesis gene phbC in the photosynthetic bacterium Rhodopseudomonas palustris WP3-5. The experimental results indicated that the mutant strain Rps. palustris M23 could be successfully screened. Fluorescent observation with Nile blue staining showed no significant PHB granule accumulation in the mutant cells. Batch mode experiments using acetic acid as a carbon source revealed a 29.1% and 25.9% hydrogen gas content from M23 and WP3-5, respectively. However, this trend did not appear when using propionic acid as carbon source. Under continuous operation, the hydrogen gas content from M23 could be maintained above 72%. The average hydrogen production rates of the WP3-5 and M23 strains were 264 mL-H(2)/L/day and 457 mL-H(2)/L/day, respectively. The total biogas volume collected from M23 was 1.7 times higher than that from the wild type. Copyright © 2010 Elsevier Ltd. All rights reserved.

  4. Microaerophilic growth and induction of the photosynthetic reaction center in Rhodopseudomonas viridis

    SciTech Connect

    Lang, F.S.; Oesterhelt, D.

    1989-05-01

    Rhodopseudomonas viridis was grown in liquid culture at 30 degrees C anaerobically in light (generation time, 13 h) and under microaerophilic growth conditions in the dark (generation time, 24 h). The bacterium could be cloned at the same temperature anaerobically in light (1 week) and aerobically in the dark (3 to 4 weeks) if oxygen was limited to 0.1%. Oxygen could not be replaced by dimethyl sulfoxide, potassium nitrate, or sodium nitrite as a terminal electron acceptor. No growth was observed anaerobically in darkness or in the light when air was present. A variety of additional carbon sources were used to supplement the standard succinate medium, but enhanced stationary-phase cell density was observed only with glucose. Conditions for induction of the photosynthetic reaction center upon the change from microaerophilic to phototrophic growth conditions were investigated and optimized for a mutant functionally defective in phototrophic growth. R. viridis consumed about 20-fold its cell volume of oxygen per hour during respiration. The MICs of ampicillin, kanamycin, streptomycin, tetracycline, 1-methyl-3-nitro-1-nitrosoguanidine, and terbutryn were determined.

  5. Characterization of nif regulatory genes in Rhodopseudomonas capsulata using lac gene fusions.

    PubMed

    Kranz, R G; Haselkorn, R

    1985-01-01

    Translational fusions of the Escherichia coli lacZYA operon to Rhodopseudomonas capsulata nif genes were obtained by using mini-MudII1734 [Castilho et al., J. Bacteriol. 158 (1984) 488-495] inserts into cloned fragments of R. capsulata DNA. A lac fusion to the nifH gene, which encodes dinitrogenase reductase, was used to classify Nif- mutations occurring in regulatory genes. Nine mutations were unable to activate nifHDK transcription. The nine mutations define four nif regulatory genes. Three of these genes are located on the same R. capsulata 8.4-kb EcoRI fragment. Each is transcribed independently. One of these (complementing mutant J61) is partially homologous with the ntrC gene of Escherichia coli, based on Southern hybridization. The fourth nif regulatory gene (complementing mutants LJ1, AH1 and AH3) is unlinked to the others. Lac fusions to all four regulatory genes were constructed. Each regulatory gene is weakly expressed compared to derepressed nifH and partially repressed in the presence of ammonia.

  6. Rhodopseudomonas palustris CGA010 Proteome Implicates Extracytoplasmic Function Sigma Factor in Stress Response

    DOE PAGES

    Allen, Michael S.; Hurst, Gregory B.; Lu, Tse-Yuan S.; ...

    2015-04-08

    Rhodopseudomonas palustris encodes 16 extracytoplasmic function (ECF) σ factors. In this paper, to begin to investigate the regulatory network of one of these ECF σ factors, the whole proteome of R. palustris CGA010 was quantitatively analyzed by tandem mass spectrometry from cultures episomally expressing the ECF σRPA4225 (ecfT) versus a WT control. Among the proteins with the greatest increase in abundance were catalase KatE, trehalose synthase, a DPS-like protein, and several regulatory proteins. Alignment of the cognate promoter regions driving expression of several upregulated proteins suggested a conserved binding motif in the -35 and -10 regions with the consensus sequencemore » GGAAC-18N-TT. Additionally, the putative anti-σ factor RPA4224, whose gene is contained in the same predicted operon as RPA4225, was identified as interacting directly with the predicted response regulator RPA4223 by mass spectrometry of affinity-isolated protein complexes. Furthermore, another gene (RPA4226) coding for a protein that contains a cytoplasmic histidine kinase domain is located immediately upstream of RPA4225. The genomic organization of orthologs for these four genes is conserved in several other strains of R. palustris as well as in closely related α-Proteobacteria. Finally, taken together, these data suggest that ECF σRPA4225 and the three additional genes make up a sigma factor mimicry system in R. palustris.« less

  7. Extraction of extracellular polymeric substances from the photosynthetic bacterium Rhodopseudomonas acidophila.

    PubMed

    Sheng, Guo-Ping; Yu, Han-Qing; Yu, Zhou

    2005-04-01

    Among the four methods for extracting extracellular polymeric substances (EPS) from Rhodopseudomonas acidophila (EDTA, NaOH, H(2)SO(4), heating/centrifugation), EDTA extraction was found to be the most effective. The contents of the major components of EPS from R. acidophila, i.e., carbohydrate, protein and nucleic acid, were 6.5, 58.4 and 5.4 mg g(-1) dry cells, respectively. The optimum extraction time was 1-3 h and the EDTA dosage was approximately 2.8 g g(-1) dry cells. Under these conditions, no cell lysis was observed. The EPS content and the percentage of the three main components were greatly dependent on the extraction method. The intensity of absorption peaks for photosynthetic pigments in the UV-visible spectrum of bacteria remained unchanged prior to and after EDTA extraction; and no pigment peaks appeared in the EPS spectrum. This suggests that few cells were destroyed and lysis did not occur. UV-visible spectrum analysis, an easy and rapid technique, could be used to monitor cell lysis during EPS extraction from R. acidophila.

  8. Disordered exciton model for the core light-harvesting antenna of Rhodopseudomonas viridis.

    PubMed

    Novoderezhkin, V; Monshouwer, R; van Grondelle, R

    1999-08-01

    In this work we explain the spectral heterogeneity of the absorption band (. Biochim. Biophys. Acta. 1229:373-380), as well as the spectral evolution of pump-probe spectra for membranes of Rhodopseudomonas (Rps.) viridis. We propose an exciton model for the LH1 antenna of Rps. viridis and assume that LH1 consists of 24-32 strongly coupled BChl b molecules that form a ring-like structure with a 12- or 16-fold symmetry. The orientations and pigment-pigment distances of the BChls were taken to be the same as for the LH2 complexes of BChl a-containing bacteria. The model gave an excellent fit to the experimental results. The amount of energetic disorder necessary to explain the results could be precisely estimated and gave a value of 440-545 cm(-1) (full width at half-maximum) at low temperature and 550-620 cm(-1) at room temperature. Within the context of the model we calculated the coherence length of the steady-state exciton wavepacket to correspond to a delocalization over 5-10 BChl molecules at low temperature and over 4-6 molecules at room temperature. Possible origins of the fast electronic dephasing and the observed long-lived vibrational coherence are discussed.

  9. Assembly and structural organization of pigment-protein complexes in membranes of Rhodopseudomonas sphaeroides.

    PubMed

    Hunter, C N; Pennoyer, J D; Niederman, R A

    1982-01-01

    The B875 and B800-850 light-harvesting pigment-protein complexes of Rhodopseudomonas sphaeroides are characterized further by lithium dodecyl sulfate/polyacrylamide gel electrophoresis at 4 degrees C. Bacteriochlorophyll a was shown in reconstruction studies to remain complexed with its respective binding proteins during this procedure. From distributions in these gels, a quantitative description for the arrangement of the complexes is proposed. Assembly of the complexes was examined in delta-aminolevulinate-requiring mutant H-5 after a shift from high- to low-light intensity. After 10 h of delta-[3H]aminolevulinate labeling, the specific radioactivity of bacteriochlorophyll in a fraction containing putative membrane invaginations reached the maximal level, while that of the mature photosynthetic membrane was at only one-third this level. This suggests that membrane invaginations are sites of preferential bacteriochlorophyll synthesis in which completed pigment-proteins exist transiently. Analysis of the 3H distribution after electrophoretic separation further suggests that photosynthetic membranes grow mainly by addition of B800-850 to preformed membrane consisting largely of B875 and photochemical reaction centers. These results corroborate the above model for the structural organization of the light-harvesting system and indicate that the structurally and functionally discrete B800-850 pool is not completely assembled until all B875 sites for B800-850 interactions are occupied.

  10. Hydrogen Photoproduction by Rhodopseudomonas palustris 42OL Cultured at High Irradiance under a Semicontinuous Regime

    PubMed Central

    Carlozzi, Pietro

    2012-01-01

    The main goal of this study was to increase the hydrogen production rate improving the culture technique and the photobioreactor performances. Experiments were carried out at a constant culture temperature of 30°C and at an average irradiance of 480 W m−2 using a cylindrical photobioreactor (4.0 cm, internal diameter). The culture technique, namely, the semicontinuous regime for growing Rhodopseudomonas palustris 42OL made it possible to achieve a very high daily hydrogen production rate of 594 ± 61 mL (H2) L−1 d−1. This value, never reported for this strain, corresponds to about 25 mL (H2) L−1 h−1, and it was obtained when the hydraulic retention time (HRT) was of 225 hours. Under the same growth conditions, a very high biomass production rate (496 ± 45 mg (dw) L−1 d−1) was also achieved. Higher or lower HRTs caused a reduction in both the hydrogen and the biomass production rates. The malic-acid removal efficiency (MAre) was always higher than 90%. The maximal hydrogen yield was 3.03 mol H2 mol MA−1 at the HRT of 360 hours. The highest total energy conversion efficiency was achieved at the HRT of 225 hours. PMID:22910542

  11. Hydrogen photoproduction by Rhodopseudomonas palustris 42OL cultured at high irradiance under a semicontinuous regime.

    PubMed

    Carlozzi, Pietro

    2012-01-01

    The main goal of this study was to increase the hydrogen production rate improving the culture technique and the photobioreactor performances. Experiments were carried out at a constant culture temperature of 30°C and at an average irradiance of 480 W m(-2) using a cylindrical photobioreactor (4.0 cm, internal diameter). The culture technique, namely, the semicontinuous regime for growing Rhodopseudomonas palustris 42OL made it possible to achieve a very high daily hydrogen production rate of 594 ± 61 mL (H(2)) L(-1) d(-1). This value, never reported for this strain, corresponds to about 25 mL (H(2)) L(-1) h(-1), and it was obtained when the hydraulic retention time (HRT) was of 225 hours. Under the same growth conditions, a very high biomass production rate (496 ± 45 mg (dw) L(-1) d(-1)) was also achieved. Higher or lower HRTs caused a reduction in both the hydrogen and the biomass production rates. The malic-acid removal efficiency (MA(re)) was always higher than 90%. The maximal hydrogen yield was 3.03 mol H(2) mol MA(-1) at the HRT of 360 hours. The highest total energy conversion efficiency was achieved at the HRT of 225 hours.

  12. Characterization of exopolymeric substances from selected Rhodopseudomonas palustris strains and their ability to adsorb sodium ions.

    PubMed

    Nunkaew, Tomorn; Kantachote, Duangporn; Nitoda, Teruhiko; Kanzaki, Hiroshi; Ritchie, Raymond J

    2015-01-22

    Removal of Na(+) by binding with exopolymeric substances (EPS) from Rhodopseudomonas palustris TN114 and PP803 was investigated. The moderate negative correlation pairs (rp) between remaining Alcian blue and amount of Na(+) adsorbed on EPS from strains TN114 and PP803 were -0.652 and -0.609. Both strains showed positive relationships between the amounts of EPS produced and bacterial growth. EPS from strain PP803 had a higher efficiency in removing Na(+) than the EPS from strain TN114 based on their EC50 values (1.79 and 1.49 mg/mL for TN114 and PP803, respectively). The principal component from EPS of strain PP803 which was responsible for salt removal was purified and it was identified as a polysaccharide (≈18 kDa) mainly composed of galacturonic acid. Overall results suggested that EPS is a key factor that our strains used to bind Na(+) allowing their survival in high NaCl concentrations. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Purification and characterization of the cytochrome c oxidase from Rhodopseudomonas sphaeroides.

    PubMed

    Gennis, R B; Casey, R P; Azzi, A; Ludwig, B

    1982-06-15

    When grown aerobically in the dark, Rhodopseudomonas sphaeroides develops a respiratory chain similar to that in mitochondria and the photosynthetic apparatus is suppressed. The aa3-type cytochrome c oxidase from Rps. sphaeroides has been purified in Triton X-100 by affinity chromatography with Sepharose 4B coupled to yeast cytochrome c. The oxidase contains 14 nmol heme a/mg protein and is composed of three polypeptide subunits with relative molecular masses of 45000, 37000 and 35000. The enzyme is highly active in the presence of detergents, with a maximal velocity of 300 s-1/mol oxidase using either yeast or horse-heart cytochrome c. The Rps. sphaeroides oxidase is cross-reactive with antibodies directed against the oxidases from Paracoccus denitrificans and Saccharomyces cerevisiae. A particularly close relationship is indicated in the case of P. denitrificans. The Rps. sphaeroides oxidase has been incorporated into phospholipid vesicles. The resulting oxidase in these vesicles demonstrates high enzymatic activity and a respiratory control ratio of 5. Using these vesicles, no evidence for proton extrusion accompanying cytochrome c oxidation was observed. The data suggest that the Rps. sphaeroides oxidase does not function as a proton pump.

  14. Identification and characterization of Rhodopseudomonas palustris TIE-1 hopanoid biosynthesis mutants

    PubMed Central

    Welander, Paula V.; Doughty, David M.; Wu, Chia-Hung; Mehay, Sabine; Summons, Roger E.; Newman, Dianne K.

    2012-01-01

    Hopanes preserved in both modern and ancient sediments are recognized as the molecular fossils of bacteriohopanepolyols, pentacyclic hopanoid lipids. Based on the phylogenetic distribution of hopanoid production by extant bacteria, hopanes have been used as indicators of specific bacterial groups and/or their metabolisms. However, our ability to interpret them ultimately depends on understanding the physiological roles of hopanoids in modern bacteria. Towards this end, we set out to identify genes required for hopanoid biosynthesis in the anoxygenic phototroph Rhodopseudomonas palustris TIE-1 to enable selective control of hopanoid production. We attempted to delete seventeen genes within a putative hopanoid biosynthetic gene cluster to determine their role, if any, in hopanoid biosynthesis. Two genes, hpnH and hpnG, are required to produce both bacteriohopanetetrol and aminobacteriohopanetriol, whereas a third gene, hpnO, is required only for aminobacteriohopanetriol production. None of the genes in this cluster are required to exclusively synthesize bacteriohopanetetrol, indicating that at least one other hopanoid biosynthesis gene is located elsewhere on the chromosome. Physiological studies with the different deletion mutants demonstrated that unmethylated and C30 hopanoids are sufficient to maintain cytoplasmic but not outer membrane integrity. These results imply that hopanoid modifications, including methylation of the A-ring and the addition of a polar head group, may have biological functions beyond playing a role in membrane permeability. PMID:22221333

  15. Lipid remodeling in Rhodopseudomonas palustris TIE-1 upon loss of hopanoids and hopanoid methylation.

    PubMed

    Neubauer, C; Dalleska, N F; Cowley, E S; Shikuma, N J; Wu, C-H; Sessions, A L; Newman, D K

    2015-09-01

    The sedimentary record of molecular fossils (biomarkers) can potentially provide important insights into the composition of ancient organisms; however, it only captures a small portion of their original lipid content. To interpret what remains, it is important to consider the potential for functional overlap between different lipids in living cells, and how the presence of one type might impact the abundance of another. Hopanoids are a diverse class of steroid analogs made by bacteria and found in soils, sediments, and sedimentary rocks. Here, we examine the trade-off between hopanoid production and that of other membrane lipids. We compare lipidomes of the metabolically versatile α-proteobacterium Rhodopseudomonas palustris TIE-1 and two hopanoid mutants, detecting native hopanoids simultaneously with other types of polar lipids by electrospray ionization mass spectrometry. In all strains, the phospholipids contain high levels of unsaturated fatty acids (often >80%). The degree to which unsaturated fatty acids are modified to cyclopropyl fatty acids varies by phospholipid class. Deletion of the capacity for hopanoid production is accompanied by substantive changes to the lipidome, including a several-fold rise of cardiolipins. Deletion of the ability to make methylated hopanoids has a more subtle effect; however, under photoautotrophic growth conditions, tetrahymanols are upregulated twofold. Together, these results illustrate that the 'lipid fingerprint' produced by a micro-organism can vary depending on the growth condition or loss of single genes, reminding us that the absence of a biomarker does not necessarily imply the absence of a particular source organism.

  16. Physiology and Mechanism of Phototrophic Fe(II) Oxidation by Rhodopseudomonas palustris TIE-1

    NASA Astrophysics Data System (ADS)

    Jiao, Y.; Newman, D.

    2007-12-01

    Phototrophic Fe(II)-oxidizing bacteria use electrons from ferrous iron [Fe(II)] and energy from light to drive reductive CO2 fixation. This metabolism is thought to be ancient in origin, and plays an important role in environmental iron cycling. It has been implicated in the deposition of Banded Iron Formations, a class of ancient sedimentary iron deposits. Consistent with this hypothesis, we discovered that hydrogen gas, a thermodynamically favorable electron donor to Fe(II), in an Archean atmosphere would not have inhibited phototrophic Fe(II) oxidation. To understand this physiology and the connection to BIF formation at the molecular level, the mechanisms of phototrophic Fe(II) oxidation were examined in a model organism Rhodopseudomonas palustris TIE-1. Increased expression of a putative decaheme c-type cytochrome, encoded by pioA, was observed when cells were grown under Fe(II)-oxidizing conditions. Two genes located immediately downstream of pioA in the same operon, pioB and pioC, encode a putative outer membrane beta-barrel protein and a putative high potential iron-sulfur protein, respectively. Deletion studies demonstrated that all three genes are involved in phototrophic Fe(II) oxidation. This study provides our first insight into the molecular mechanisms of this metabolism, which will be further characterized by in vitro biochemical studies.

  17. H2 production in Rhodopseudomonas palustris as a way to cope with high light intensities.

    PubMed

    Muzziotti, Dayana; Adessi, Alessandra; Faraloni, Cecilia; Torzillo, Giuseppe; De Philippis, Roberto

    2016-06-01

    The ability of coping with the damaging effects of high light intensity represents an essential issue when purple non-sulfur bacteria (PNSB) are grown under direct sunlight for photobiological hydrogen production. This study was aimed at investigating whether H2 photo-evolution could represent, for Rhodopseudomonas palustris 42OL, a safety valve to dissipate an excess of reducing power generated under high light intensities. The physiological status of this strain was assessed under anaerobic (AnG) and aerobic (AG) growing conditions and under H2-producing (HP) conditions at low and high light intensities. The results obtained clearly showed that Fv/Fm ratio was significantly affected by the light intensity under which R. palustris 42OL cells were grown, under either AnG or AG conditions, while, under HP, it constantly remained at its highest value. The increase in light intensity significantly increased the H2 production rate, which showed a positive correlation with the maximum electron transfer rate (rETRmax). These findings are important for optimization of hydrogen production by PNSB under solar light.

  18. Phototrophic utilization of taurine by the purple nonsulfur bacteria Rhodopseudomonas palustris and Rhodobacter sphaeroides.

    PubMed

    Novak, Ryan T; Gritzer, Rachel F; Leadbetter, Edward R; Godchaux, Walter

    2004-06-01

    Taurine metabolism by two phototrophically grown purple nonsulfur bacteria enrichment isolates has been examined. Rhodopseudomonas palustris (strain Tau1) grows with taurine as a sole electron donor, sulfur and nitrogen source during photoautotrophic growth. Rhodobacter sphaeroides (strain Tau3) grows on the compound as sole electron donor, sulfur and nitrogen source, and partial carbon source, in the presence of CO(2) during photoheterotrophic growth. Both organisms utilize an inducible taurine-pyruvate aminotransferase and a sulfoacetaldehyde acetyltransferase. The products of this metabolism are bisulfite and acetyl phosphate. Bisulfite ultimately was oxidized to sulfate, but this was not an adequate source of electrons for photometabolism. Experiments using either [U-(14)C]taurine or (14)CO(2) demonstrated that Rb. sphaeroides Tau3 assimilated the carbon from approximately equimolar amounts of taurine and exogenous CO(2). The taurine-carbon assimilation was not diminished by excess non-radioactive bicarbonate. Malate synthase (but not isocitrate lyase) was induced in these taurine-grown cells. It is concluded that assimilation of taurine carbon occurs through an intermediate other than CO(2). Similar labelling experiments with Rp. palustris Tau1 determined that taurine is utilized only as an electron donor for the reduction of CO(2), which contributes all the cell carbon. Photoautotrophic metabolism was confirmed in this organism by the absence of either malate synthase or isocitrate lyase in taurine+CO(2)-grown cells. Culture collection strains of these two bacteria did not utilize taurine in these fashions.

  19. Rhodopseudomonas palustris CGA010 Proteome Implicates Extracytoplasmic Function Sigma Factor in Stress Response

    SciTech Connect

    Allen, Michael S.; Hurst, Gregory B.; Lu, Tse-Yuan S.; Perry, Leslie M.; Pan, Chongle; Lankford, Patricia K.; Pelletier, Dale A.

    2015-04-08

    Rhodopseudomonas palustris encodes 16 extracytoplasmic function (ECF) σ factors. In this paper, to begin to investigate the regulatory network of one of these ECF σ factors, the whole proteome of R. palustris CGA010 was quantitatively analyzed by tandem mass spectrometry from cultures episomally expressing the ECF σRPA4225 (ecfT) versus a WT control. Among the proteins with the greatest increase in abundance were catalase KatE, trehalose synthase, a DPS-like protein, and several regulatory proteins. Alignment of the cognate promoter regions driving expression of several upregulated proteins suggested a conserved binding motif in the -35 and -10 regions with the consensus sequence GGAAC-18N-TT. Additionally, the putative anti-σ factor RPA4224, whose gene is contained in the same predicted operon as RPA4225, was identified as interacting directly with the predicted response regulator RPA4223 by mass spectrometry of affinity-isolated protein complexes. Furthermore, another gene (RPA4226) coding for a protein that contains a cytoplasmic histidine kinase domain is located immediately upstream of RPA4225. The genomic organization of orthologs for these four genes is conserved in several other strains of R. palustris as well as in closely related α-Proteobacteria. Finally, taken together, these data suggest that ECF σRPA4225 and the three additional genes make up a sigma factor mimicry system in R. palustris.

  20. Calculated coupling of electron and proton transfer in the photosynthetic reaction center of Rhodopseudomonas viridis.

    PubMed Central

    Lancaster, C R; Michel, H; Honig, B; Gunner, M R

    1996-01-01

    Based on new Rhodopseudomonas (Rp.) viridis reaction center (RC) coordinates with a reliable structure of the secondary acceptor quinone (QB) site, a continuum dielectric model and finite difference technique have been used to identify clusters of electrostatically interacting ionizable residues. Twenty-three residues within a distance of 25 A from QB (QB cluster) have been shown to be strongly electrostatically coupled to QB, either directly or indirectly. An analogous cluster of 24 residues is found to interact with QA (QA cluster). Both clusters extend to the cytoplasmic surface in at least two directions. However, the QB cluster differs from the QA cluster in that it has a surplus of acidic residues, more strong electrostatic interactions, is less solvated, and experiences a strong positive electrostatic field arising from the polypeptide backbone. Consequently, upon reduction of QA or QB, it is the QB cluster, and not the QA cluster, which is responsible for substoichiometric proton uptake at neutral pH. The bulk of the changes in the QB cluster are calculated to be due to the protonation of a tightly coupled cluster of the three Glu residues (L212, H177, and M234) within the QB cluster. If the lifetime of the doubly reduced state QB2- is long enough, Asp M43 and Ser L223 are predicted to also become protonated. The calculated complex titration behavior of the strongly interacting residues of the QB cluster and the resulting electrostatic response to electron transfer may be a common feature in proton-transferring membrane protein complexes. Images FIGURE 2 p2482-a FIGURE 6 FIGURE 8 FIGURE 10 PMID:8744288

  1. Rhodopseudomonas palustris Regulons Detected by Cross-Species Analysis of Alphaproteobacterial Genomes

    PubMed Central

    Conlan, Sean; Lawrence, Charles; McCue, Lee Ann

    2005-01-01

    Rhodopseudomonas palustris, an α-proteobacterium, carries out three of the chemical reactions that support life on this planet: the conversion of sunlight to chemical-potential energy; the absorption of carbon dioxide, which it converts to cellular material; and the fixation of atmospheric nitrogen into ammonia. Insight into the transcription-regulatory network that coordinates these processes is fundamental to understanding the biology of this versatile bacterium. With this goal in mind, we predicted regulatory signals genomewide, using a two-step phylogenetic-footprinting and clustering process that we had developed previously. In the first step, 4,963 putative transcription factor binding sites, upstream of 2,044 genes and operons, were identified using cross-species Gibbs sampling. Bayesian motif clustering was then employed to group the cross-species motifs into regulons. We have identified 101 putative regulons in R. palustris, including 8 that are of particular interest: a photosynthetic regulon, a flagellar regulon, an organic hydroperoxide resistance regulon, the LexA regulon, and four regulons related to nitrogen metabolism (FixK2, NnrR, NtrC, and σ54). In some cases, clustering allowed us to assign functions to proteins that previously had been annotated with only putative functions; we have identified RPA0828 as the organic hydroperoxide resistance regulator and RPA1026 as a cell cycle methylase. In addition to predicting regulons, we identified a novel inverted repeat that likely forms a highly conserved stem-loop and that occurs downstream of over 100 genes. PMID:16269786

  2. Polypyrroles formed from porphobilinogen and amines by uroporphyrinogen synthetase of Rhodopseudomonas spheroides

    PubMed Central

    Davies, Richard C.; Neuberger, Albert

    1973-01-01

    1. Uroporphyrinogen I synthetase of Rhodopseudomonas spheroides was purified more than 200-fold from the soluble protein of broken bacterial cells. The enzyme had molecular weight 36000, an isoelectric point of 4.46 and migrated as a single active protein band on disc-gel electrophoresis at pH7.5 and 8.9. 2. The enzyme consumed porphobilinogen and formed uroporphyrinogen at pH8.2 without the accumulation of intermediates. In the presence of hydroxylamine, ammonia or methoxyamine the production of porphyrinogen was inhibited and the enzyme formed open-chain polypyrroles instead. 3. These polypyrroles behaved like uroporphyrinogen on Sephadex G-25; they were colourless and had unsubstituted α-pyrrolic positions. The inhibitory amines were incorporated into the molecules. 4. The polypyrroles formed porphyrins non-enzymically and the cyclization reaction was accompanied by the release of the inhibitory amine. Exchange of the amino function of the original porphobilinogen in the polypyrrole was complete with hydroxylamine and almost complete with methoxyamine, both ammonia and methoxyamine being present in the polypyrrolic material. 5. The behaviour, properties and composition of the radioactive hydroxylamine derivative were consistent with a tetrapyrrolic structure, probably a pyrrylmethane, that was not cyclized, rather than with di-, tri- or penta-pyrrolic structures. No monopyrrolic or dipyrrolic Ehrlich-positive material was released on cyclization. The ammonia and methoxyamine derivatives had properties similar to the hydroxylamine derivative. 6. Another modified pyrrole was detected only in experiments with hydroxylamine. It differed from both porphobilinogen and known dipyrroles and appeared to be a monopyrrole. 7. The participation of positively charged reaction centres in the enzymic mechanism, particularly in the cyclization step, is discussed. PMID:4542566

  3. Functional Genomic Analysis of Three Nitrogenase Isozymes in the Photosynthetic Bacterium Rhodopseudomonas palustris‡

    PubMed Central

    Oda, Yasuhiro; Samanta, Sudip K.; Rey, Federico E.; Wu, Liyou; Liu, Xiudan; Yan, Tingfen; Zhou, Jizhong; Harwood, Caroline S.

    2005-01-01

    The photosynthetic bacterium Rhodopseudomonas palustris is one of just a few prokaryotes described so far that has vnf and anf genes for alternative vanadium cofactor (V) and iron cofactor (Fe) nitrogenases in addition to nif genes for a molybdenum cofactor (Mo) nitrogenase. Transcriptome data indicated that the 32 genes in the nif gene cluster, but not the anf or vnf genes, were induced in wild-type and Mo nitrogenase-expressing strains grown under nitrogen-fixing conditions in Mo-containing medium. Strains that were unable to express a functional Mo nitrogenase due to mutations in Mo nitrogenase structural genes synthesized functional V and Fe nitrogenases and expressed vnf and anf genes in nitrogen-fixing growth media that contained Mo and V at concentrations far in excess of those that repress alternative nitrogenase gene expression in other bacteria. Thus, not only does R. palustris have multiple enzymatic options for nitrogen fixation, but in contrast to reports on other nitrogen-fixing bacteria, the expression of its alternative nitrogenases is not repressed by transition metals. Between 95 and 295 genes that are not directly associated with nitrogenase synthesis and assembly were induced under nitrogen-fixing conditions, depending on which nitrogenase was being used by R. palustris. Genes for nitrogen acquisition were expressed at particularly high levels during alternative nitrogenase-dependent growth. This suggests that alternative nitrogenase-expressing cells are relatively starved for nitrogen and raises the possibility that fixed nitrogen availability may be the primary signal that controls the synthesis of the V and Fe nitrogenases. PMID:16267302

  4. How posttranslational modification of nitrogenase is circumvented in Rhodopseudomonas palustris strains that produce hydrogen gas constitutively.

    PubMed

    Heiniger, Erin K; Oda, Yasuhiro; Samanta, Sudip K; Harwood, Caroline S

    2012-02-01

    Nitrogenase catalyzes the conversion of dinitrogen gas (N(2)) and protons to ammonia and hydrogen gas (H(2)). This is a catalytically difficult reaction that requires large amounts of ATP and reducing power. Thus, nitrogenase is not normally expressed or active in bacteria grown with a readily utilized nitrogen source like ammonium. nifA* mutants of the purple nonsulfur phototrophic bacterium Rhodopseudomonas palustris have been described that express nitrogenase genes constitutively and produce H(2) when grown with ammonium as a nitrogen source. This raised the regulatory paradox of why these mutants are apparently resistant to a known posttranslational modification system that should switch off the activity of nitrogenase. Microarray, mutation analysis, and gene expression studies showed that posttranslational regulation of nitrogenase activity in R. palustris depends on two proteins: DraT2, an ADP-ribosyltransferase, and GlnK2, an NtrC-regulated P(II) protein. GlnK2 was not well expressed in ammonium-grown NifA* cells and thus not available to activate the DraT2 nitrogenase modification enzyme. In addition, the NifA* strain had elevated nitrogenase activity due to overexpression of the nif genes, and this increased amount of expression overwhelmed a basal level of activity of DraT2 in ammonium-grown cells. Thus, insufficient levels of both GlnK2 and DraT2 allow H(2) production by an nifA* mutant grown with ammonium. Inactivation of the nitrogenase posttranslational modification system by mutation of draT2 resulted in increased H(2) production by ammonium-grown NifA* cells.

  5. Hydrogen production under salt stress conditions by a freshwater Rhodopseudomonas palustris strain.

    PubMed

    Adessi, Alessandra; Concato, Margherita; Sanchini, Andrea; Rossi, Federico; De Philippis, Roberto

    2016-03-01

    Hydrogen represents a possible alternative energy carrier to face the growing request for energy and the shortage of fossil fuels. Photofermentation for the production of H2 constitutes a promising way for integrating the production of energy with waste treatments. Many wastes are characterized by high salinity, and polluted seawater can as well be considered as a substrate. Moreover, the application of seawater for bacterial culturing is considered cost-effective. The aims of this study were to assess the capability of the metabolically versatile freshwater Rhodopseudomonas palustris 42OL of producing hydrogen on salt-containing substrates and to investigate its salt stress response strategy, never described before. R. palustris 42OL was able to produce hydrogen in media containing up to 3 % added salt concentration and to grow in media containing up to 4.5 % salinity without the addition of exogenous osmoprotectants. While the hydrogen production performances in absence of sea salts were higher than in their presence, there was no significant difference in performances between 1 and 2 % of added sea salts. Nitrogenase expression levels indicated that the enzyme was not directly inhibited during salt stress, but a regulation of its expression may have occurred in response to salt concentration increase. During cell growth and hydrogen production in the presence of salts, trehalose was accumulated as a compatible solute; it protected the enzymatic functionality against salt stress, thus allowing hydrogen production. The possibility of producing hydrogen on salt-containing substrates widens the range of wastes that can be efficiently used in production processes.

  6. Biotransformation of water lettuce (Pistia stratiotes) to biohydrogen by Rhodopseudomonas palustris.

    PubMed

    Corneli, Elisa; Adessi, Alessandra; Olguín, Eugenia J; Ragaglini, Giorgio; García-López, Daniel A; De Philippis, Roberto

    2017-10-03

    Aim of the paper was to assess the feasibility of producing hydrogen as a biofuel by photofermentation of fermented water lettuce (Pistia stratiotes L.) waste biomass, after a nitrogen-stripping treatment. A natural (42OL) and an engineered strain (CGA676, with low-ammonium sensitivity) of Rhodopseudomonas palustris were used for producing hydrogen. The stripping procedure was highly effective for ammonium removal, with an acceptable selectivity (91% of ammonium was removed; only 14% of total organic acids were lost). Both strains were able to produce hydrogen only in the nitrogen-stripped substrate. The natural strain R.palustris 42OL showed a higher Biochemical Hydrogen Potential (1224 mL L(-1) vs 720 mL L(-1) ; 50.0 mol m(-3) vs 29.4 mol m(-3) ), but at a lower rate (5.6 mL L(-1) h(-1) vs 7.3 mL L(-1) h(-1) ; 0.23 mol m(-3) h(-1) vs 0.29 mol m(-3) h(-1) ) than strain CGA676. Water lettuce waste biomass can be used for biofuel production, after hydrolization, fermentation and nitrogen stripping. The investigation on novel, low cost and sustainable biomasses as feedstocks for biofuel production is a priority. Aquatic plants do not compete for arable land. Moreover, water lettuce is a floating and invasive weed, thus its biomass must be harvested when detrimental, and can now be biotransformed in clean hydrogen. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

  7. A Novel Electrophototrophic Bacterium Rhodopseudomonas palustris Strain RP2, Exhibits Hydrocarbonoclastic Potential in Anaerobic Environments

    PubMed Central

    Venkidusamy, Krishnaveni; Megharaj, Mallavarapu

    2016-01-01

    An electrophototrophic, hydrocarbonoclastic bacterium Rhodopseudomonas palustris stain RP2 was isolated from the anodic biofilms of hydrocarbon fed microbial electrochemical remediation systems (MERS). Salient properties of the strain RP2 were direct electrode respiration, dissimilatory metal oxide reduction, spore formation, anaerobic nitrate reduction, free living diazotrophy and the ability to degrade n-alkane components of petroleum hydrocarbons (PH) in anoxic, photic environments. In acetate fed microbial electrochemical cells, a maximum current density of 305 ± 10 mA/m2 (1000Ω) was generated (power density 131.65 ± 10 mW/m2) by strain RP2 with a coulombic efficiency of 46.7 ± 1.3%. Cyclic voltammetry studies showed that anaerobically grown cells of strain RP2 is electrochemically active and likely to transfer electrons extracellularly to solid electron acceptors through membrane bound compounds, however, aerobically grown cells lacked the electrochemical activity. The ability of strain RP2 to produce current (maximum current density 21 ± 3 mA/m2; power density 720 ± 7 μW/m2, 1000 Ω) using PH as a sole energy source was also examined using an initial concentration of 800 mg l-1 of diesel range hydrocarbons (C9-C36) with a concomitant removal of 47.4 ± 2.7% hydrocarbons in MERS. Here, we also report the first study that shows an initial evidence for the existence of a hydrocarbonoclastic behavior in the strain RP2 when grown in different electron accepting and illuminated conditions (anaerobic and MERS degradation). Such observations reveal the importance of photoorganotrophic growth in the utilization of hydrocarbons from contaminated environments. Identification of such novel petrochemical hydrocarbon degrading electricigens, not only expands the knowledge on the range of bacteria known for the hydrocarbon bioremediation but also shows a biotechnological potential that goes well beyond its applications to MERS. PMID:27462307

  8. Increased photoproduction of hydrogen by non-autotrophic mutants of Rhodopseudomonas capsulata.

    PubMed Central

    Willison, J C; Madern, D; Vignais, P M

    1984-01-01

    Non-autotrophic ( Aut -) mutants of Rhodopseudomonas capsulata B10 were tested for their efficiency of nitrogenase-mediated H2 production. Three of these mutants ( IR3 , IR4 and IR5 ) showed an increase stoichiometry of H2 production, mediated by nitrogenase, from certain organic substrates. For example, in a medium containing 7 mM-L-glutamate as nitrogen source, strain IR4 produced 10-20% more H2 than did the wild type with DL-lactate or L-malate as major carbon source, 20-50% more H2 with DL-malate, and up to 70% more with D-malate. Strain IR4 was deficient in 'uptake' hydrogenase activity as measured by H2-dependent reduction of Methylene Blue or Benzyl Viologen. However, this observation did not explain the increased efficiency of H2 production, since H2 uptake (H2 recycling) was undetectable in cells of the wild type. Instead, increased H2 production by the mutant appeared to be due to an improved conversion of organic substrates to H2 and CO2, presumably due to an altered carbon metabolism. The metabolism of D-malate by different strains was studied. An NAD+-dependent D-malic enzyme was synthesized constitutively by the wild type, and showed a Km for D-malate of 3 mM. The activity of this enzyme was approx. 50% higher in strain IR4 than in the wild type, and the mutant also grew twice as fast as the wild type with D-malate as sole carbon source. PMID:6146310

  9. Low light adaptation: energy transfer processes in different types of light harvesting complexes from Rhodopseudomonas palustris.

    PubMed

    Moulisová, Vladimíra; Luer, Larry; Hoseinkhani, Sajjad; Brotosudarmo, Tatas H P; Collins, Aaron M; Lanzani, Guglielmo; Blankenship, Robert E; Cogdell, Richard J

    2009-12-02

    Energy transfer processes in photosynthetic light harvesting 2 (LH2) complexes isolated from purple bacterium Rhodopseudomonas palustris grown at different light intensities were studied by ground state and transient absorption spectroscopy. The decomposition of ground state absorption spectra shows contributions from B800 and B850 bacteriochlorophyll (BChl) a rings, the latter component splitting into a low energy and a high energy band in samples grown under low light (LL) conditions. A spectral analysis reveals strong inhomogeneity of the B850 excitons in the LL samples that is well reproduced by an exponential-type distribution. Transient spectra show a bleach of both the low energy and high energy bands, together with the respective blue-shifted exciton-to-biexciton transitions. The different spectral evolutions were analyzed by a global fitting procedure. Energy transfer from B800 to B850 occurs in a mono-exponential process and the rate of this process is only slightly reduced in LL compared to high light samples. In LL samples, spectral relaxation of the B850 exciton follows strongly nonexponential kinetics that can be described by a reduction of the bleach of the high energy excitonic component and a red-shift of the low energetic one. We explain these spectral changes by picosecond exciton relaxation caused by a small coupling parameter of the excitonic splitting of the BChl a molecules to the surrounding bath. The splitting of exciton energy into two excitonic bands in LL complex is most probably caused by heterogenous composition of LH2 apoproteins that gives some of the BChls in the B850 ring B820-like site energies, and causes a disorder in LH2 structure.

  10. Nitrogenase from the photosynthetic bacterium Rhodopseudomonas capsulata: purification and molecular properties.

    PubMed Central

    Hallenbeck, P C; Meyer, C M; Vignais, P M

    1982-01-01

    Nitrogenase proteins were isolated from cultures of the photosynthetic bacterium Rhodopseudomonas capsulata grown on a limiting amount of ammonia. Under these conditions, the nitrogenase N2ase A was active in vivo, and nitrogenase activity in vitro was not dependent upon manganese and the activating factor. The nitrogenase proteins were also isolated from nitrogen-limited cultures in which the in vivo nitrogenase activity had been stopped by an ammonia shock. This nitrogenase activity, N2ase R, showed an in vitro requirement for manganese and the activating factor for maximal activity. The Mo-Fe protein (dinitrogenase) was composed of two dissimilar subunits with molecular weights of 55,000 and 59,500; the Fe protein (dinitrogenase reductase), from either type of culture, was composed of a single subunit (molecular weight), 33,500). The metal and acid labile sulfur contents of both nitrogenase proteins were similar to those found for previously isolated nitrogenases. The Fe proteins from both N2ase A and N2ase R contained phosphate and ribose, 2 mol of each per mol of N2ase R Fe protein and about 1 mol of each per mol of N2ase A Fe protein. The greatest difference between the two types of Fe protein was that the N2ase R Fe protein contained about 1 mol per mol of an adenine-like molecule, whereas the N2ase A Fe protein content of this compound was insignificant. These results are compared with various models previously presented for the short-term regulation of nitrogenase activity in the photosynthetic bacteria. PMID:6799495

  11. Insights into arsenic multi-operons expression and resistance mechanisms in Rhodopseudomonas palustris CGA009

    PubMed Central

    Zhao, Chungui; Zhang, Yi; Chan, Zhuhua; Chen, Shicheng; Yang, Suping

    2015-01-01

    Arsenic (As) is widespread in the environment and causes numerous health problems. Rhodopseudomonas palustris has been regarded as a good model organism for studying arsenic detoxification since it was first demonstrated to methylate environmental arsenic by conversion to soluble or gaseous methylated species. However, the detailed arsenic resistance mechanisms remain unknown though there are at least three arsenic-resistance operons (ars1, ars2, and ars3) in R. palustris. In this study, we investigated how arsenic multi-operons contributed to arsenic detoxification in R. palustris. The expression of ars2 or ars3 operons increased with increasing environmental arsenite (As(III)) concentrations (up to 1.0 mM) while transcript of ars1 operon was not detected in the middle log-phase (55 h). ars2 operon was actively expressed even at the low concentration of As(III) (0.01 μM), whereas the ars3 operon was expressed at 1.0 μM of As(III), indicating that there was a differential regulation mechanism for the three arsenic operons. Furthermore, ars2 and ars3 operons were maximally transcribed in the early log-phase where ars2 operon was 5.4-fold higher than that of ars3 operon. A low level of ars1 transcript was only detected at 43 h (early log-phase). Arsenic speciation analysis demonstrated that R. palustris could reduce As(V) to As(III). Collectively, strain CGA009 detoxified arsenic by using arsenic reduction and methylating arsenic mechanism, while the latter might occur with the presence of higher concentrations of arsenic. PMID:26441915

  12. Early diagenetic degradation products of bacteriohopanepolyols produced by Rhodopseudomonas palustris strain TIE-1

    NASA Astrophysics Data System (ADS)

    Eickhoff, Merle; Birgel, Daniel; Talbot, Helen M.; Peckmann, Jörn; Kappler, Andreas

    2014-05-01

    The anoxygenic purple non-sulphur bacterium Rhodopseudomonas palustris strain TIE-1 has emerged as an excellent model organism to study hopanoid biosynthesis and function. It produces several C30 hopanoids, tetrahymanol, as well as various bacteriohopanepolyols (BHPs). In addition, TIE-1 is capable of methylating various hopanoids and the non-hopanoid pentacyclic terpenoid tetrahymanol at C-2, which is rare among hopanoid producers. Here, the lipid inventory of TIE-1 under anoxic photoautotrophic growth conditions using either H2 or Fe(II) as electron donor was studied. Adenosylhopane, aminotriol and bacteriohopanetetrol (BHT) were abundant when TIE-1 was grown on H2, but aminotriol and BHT were only found in traces when grown with Fe(II). Only during growth on Fe(II), BHT was found with and without C-2 methylation (25% of both BHT homologues), whereas the other BHPs were not C-2 methylated independent of growth mode. In C30 hopanoids and tetrahymanol, C-2 methylated compounds accounted for as much as 59% of the respective C-2 methylated/non-methylated homologues during growth with Fe(II), but only up to 24% during growth with H2. This observation reveals that C-2 methylated hopanoids may have a specific function in TIE-1 and are preferably synthesized in response to elevated Fe(II) concentrations. Further, we exposed the bacterial cells of strain TIE-1 to elevated temperatures and pressure aiming to produce early degradation products of bacteriohopanepolyols (BHPs). While so far, only few BHPs such as 32,35-anhydrobacteriohopanetetrol (anhydroBHT) have been identified as early diagenetic degradation products, in our experiments bacteriohopanetetrol (BHT) and possibly adenosylhopane were degraded to various anhydroBHT isomers, and new N-containing degradation products were discovered and tentatively assigned as anhydroaminotriols.

  13. A Novel Electrophototrophic Bacterium Rhodopseudomonas palustris Strain RP2, Exhibits Hydrocarbonoclastic Potential in Anaerobic Environments.

    PubMed

    Venkidusamy, Krishnaveni; Megharaj, Mallavarapu

    2016-01-01

    An electrophototrophic, hydrocarbonoclastic bacterium Rhodopseudomonas palustris stain RP2 was isolated from the anodic biofilms of hydrocarbon fed microbial electrochemical remediation systems (MERS). Salient properties of the strain RP2 were direct electrode respiration, dissimilatory metal oxide reduction, spore formation, anaerobic nitrate reduction, free living diazotrophy and the ability to degrade n-alkane components of petroleum hydrocarbons (PH) in anoxic, photic environments. In acetate fed microbial electrochemical cells, a maximum current density of 305 ± 10 mA/m(2) (1000Ω) was generated (power density 131.65 ± 10 mW/m(2)) by strain RP2 with a coulombic efficiency of 46.7 ± 1.3%. Cyclic voltammetry studies showed that anaerobically grown cells of strain RP2 is electrochemically active and likely to transfer electrons extracellularly to solid electron acceptors through membrane bound compounds, however, aerobically grown cells lacked the electrochemical activity. The ability of strain RP2 to produce current (maximum current density 21 ± 3 mA/m(2); power density 720 ± 7 μW/m(2), 1000 Ω) using PH as a sole energy source was also examined using an initial concentration of 800 mg l(-1) of diesel range hydrocarbons (C9-C36) with a concomitant removal of 47.4 ± 2.7% hydrocarbons in MERS. Here, we also report the first study that shows an initial evidence for the existence of a hydrocarbonoclastic behavior in the strain RP2 when grown in different electron accepting and illuminated conditions (anaerobic and MERS degradation). Such observations reveal the importance of photoorganotrophic growth in the utilization of hydrocarbons from contaminated environments. Identification of such novel petrochemical hydrocarbon degrading electricigens, not only expands the knowledge on the range of bacteria known for the hydrocarbon bioremediation but also shows a biotechnological potential that goes well beyond its applications to MERS.

  14. Crystallization and preliminary X-ray analysis of the hypothetical deaminase RPB_0146 from Rhodopseudomonas palustris HaA2

    PubMed Central

    Zhang, Guofang; Yu, Dan; Yang, Guodong; Dong, Hui; Zhang, Tongcun; Liu, Xiang

    2014-01-01

    RPB_0146, a putative deaminase from Rhodopseudomonas palustris HaA2, was expressed in Escherichia coli BL21 (DE3) cells and purified using a His6 tag by Ni2+-chelating affinity chromatography for X-ray crystallographic analysis. Diffraction-quality crystals were grown by the hanging-drop vapour-diffusion method at 289 K and diffracted to a resolution of 2.44 Å using a wavelength of 1.000 Å at the Photon Factory (KEK), Japan. The crystals belonged to the orthorhombic space group P212121, with unit-cell parameters a = 66.26, b = 123.94, c = 155.95 Å. PMID:25372831

  15. Crystallization and preliminary X-ray analysis of the hypothetical deaminase RPB_0146 from Rhodopseudomonas palustris HaA2.

    PubMed

    Zhang, Guofang; Yu, Dan; Yang, Guodong; Dong, Hui; Zhang, Tongcun; Liu, Xiang

    2014-11-01

    RPB_0146, a putative deaminase from Rhodopseudomonas palustris HaA2, was expressed in Escherichia coli BL21 (DE3) cells and purified using a His6 tag by Ni2+-chelating affinity chromatography for X-ray crystallographic analysis. Diffraction-quality crystals were grown by the hanging-drop vapour-diffusion method at 289 K and diffracted to a resolution of 2.44 Å using a wavelength of 1.000 Å at the Photon Factory (KEK), Japan. The crystals belonged to the orthorhombic space group P2₁2₁2₁, with unit-cell parameters a=66.26, b=123.94, c=155.95 Å.

  16. The `heavy' subunit of the photosynthetic reaction centre from Rhodopseudomonas viridis: isolation of the gene, nucleotide and amino acid sequence

    PubMed Central

    Michel, H.; Weyer, K. A.; Gruenberg, H.; Lottspeich, F.

    1985-01-01

    The gene coding for the `heavy' subunit of the photosynthetic reaction centre from Rhodopseudomonas viridis was isolated in an expression vector. Expression of the heavy subunit in Escherichia coli was detected with antibodies raised against crystalline reaction centres. The entire subunit, and not a fusion protein, was expressed in E. coli. The protein coding region of the gene was sequenced and the amino acid sequence derived. Part of the amino acid sequence was confirmed by chemical sequence analysis of the protein. The heavy subunit consists of 258 amino acids and its mol. wt. is 28 345. It possesses one membrane-spanning α-helical segment, as was revealed by the concomitant X-ray structure analysis. ImagesFig. 1.Fig. 2. PMID:16453623

  17. Factors influencing the production of hydrogen by the purple non‐sulphur phototrophic bacterium Rhodopseudomonas acidophila KU001

    PubMed Central

    Merugu, Ramchander; Rudra, M. P. Pratap; Badgu, Nageshwari; Girisham, S.; Reddy, S. M.

    2012-01-01

    Summary Rhodopseudomonas acidophila KU001 was isolated from leather industry effluents and the effect of different cultural conditions on hydrogen production was studied. Anaerobic light induced more hydrogen production than anaerobic dark conditions. Growing cells produced more amounts of hydrogen between 96 and 144 h of incubation. Resting and growing cells preferred a pH of 6.0 ± 0.24 for hydrogen production. Succinate was the most preferred carbon source for the production of hydrogen while citrate was a poor source of carbon. Acetate and malate were also good carbon sources for hydrogen production under anaerobic light. Among the nitrogen sources, R. acidophila preferred ammonium chloride followed by urea for production of hydrogen. L‐tyrosine was the least preferred nitrogen source by both growing and resting cells. PMID:22513201

  18. Factors influencing the production of hydrogen by the purple non-sulphur phototrophic bacterium Rhodopseudomonas acidophila KU001.

    PubMed

    Merugu, Ramchander; Rudra, M P Pratap; Badgu, Nageshwari; Girisham, S; Reddy, S M

    2012-11-01

    Rhodopseudomonas acidophila KU001 was isolated from leather industry effluents and the effect of different cultural conditions on hydrogen production was studied. Anaerobic light induced more hydrogen production than anaerobic dark conditions. Growing cells produced more amounts of hydrogen between 96 and 144 h of incubation. Resting and growing cells preferred a pH of 6.0 ± 0.24 for hydrogen production. Succinate was the most preferred carbon source for the production of hydrogen while citrate was a poor source of carbon. Acetate and malate were also good carbon sources for hydrogen production under anaerobic light. Among the nitrogen sources, R. acidophila preferred ammonium chloride followed by urea for production of hydrogen. L-tyrosine was the least preferred nitrogen source by both growing and resting cells.

  19. The use of solar radiation by the photosynthetic bacterium, Rhodopseudomonas palustris: model simulation of conditions found in a shallow pond or a flatbed reactor.

    PubMed

    Ritchie, Raymond J

    2013-01-01

    Photosynthetic bacteria are attractive for biotechnology because they produce no oxygen and so H2 -production is not inhibited by oxygen as occurs in oxygenic photoorganisms. Rhodopseudomonas palustris and Afifella marina containing BChl a can use irradiances from violet near-UV (VNUV) to orange (350-650 nm) light and near-infrared (NIR) light (762-870 nm). Blue diode-based pulse amplitude modulation technology was used to measure their photosynthetic electron transport rate (ETR). ETR vs Irradiance curves fitted the waiting-in-line model--ETR = (ETRmax × E/Eopt) × exp (1 - E/Eopt). The equation was integrated over pond depth to calculate ETR of Afifella and Rhodopseudomonas in a pond up to 30 cm deep (A376, 1 cm = 0.1). Afifella saturates at low irradiances and so photoinhibition results in very low photosynthesis in a pond. Rhodopseudomonas saturates at ≈15% sunlight and shows photoinhibition in the surface layers of the pond. Total ETR is ≈335 μmol (e(-)) m(-2) s(-1) in NUV + photosynthetically active radiation light (350-700 nm). Daily ETR curves saturate at low irradiances and have a square-wave shape: ≈11-13 mol (e(-)) m(-2) day(-1) (350-700 nm). Up to 20-24% of daily 350-700 nm irradiance can be converted into ETR. NIR is absorbed by water and so competes with the bacterial RC-2 photosystem for photons. © 2013 The American Society of Photobiology.

  20. Clades of Photosynthetic Bacteria Belonging to the Genus Rhodopseudomonas Show Marked Diversity in Light-Harvesting Antenna Complex Gene Composition and Expression

    SciTech Connect

    Fixen, Kathryn R.; Oda, Yasuhiro; Harwood, Caroline S.; Eisen, Jonathan

    2015-12-22

    Many photosynthetic bacteria have peripheral light-harvesting (LH) antenna complexes that increase the efficiency of light energy capture. The purple nonsulfur photosynthetic bacteriumRhodopseudomonas palustrisproduces different types of LH complexes under high light intensities (LH2 complex) and low light intensities (LH3 and LH4 complexes). There are multiplepucBAoperons that encode the α and β peptides that make up these complexes. But, low-resolution structures, amino acid similarities between the complexes, and a lack of transcription analysis have made it difficult to determine the contributions of differentpucBAoperons to the composition and function of different LH complexes. It was also unclear how much diversity of LH complexes exists inR. palustrisand affiliated strains. To address this, we undertook an integrative genomics approach using 20 sequenced strains. Gene content analysis revealed that even closely related strains have differences in theirpucBAgene content. Transcriptome analyses of the strains grown under high light and low light revealed that the patterns of expression of thepucBAoperons varied among strains grown under the same conditions. We also found that one set of LH2 complex proteins compensated for the lack of an LH4 complex under low light intensities but not under extremely low light intensities, indicating that there is functional redundancy between some of the LH complexes under certain light intensities. The variation observed in LH gene composition and expression inRhodopseudomonasstrains likely reflects how they have evolved to adapt to light conditions in specific soil and water microenvironments.

    ImportanceRhodopseudomonas palustrisis a phototrophic purple nonsulfur bacterium that adapts its photosystem to allow growth at a range of light intensities. It does this by

  1. Promoting Effects of a Single Rhodopseudomonas palustris Inoculant on Plant Growth by Brassica rapa chinensis under Low Fertilizer Input

    PubMed Central

    Wong, Wai-Tak; Tseng, Ching-Han; Hsu, Shu-Hua; Lur, Huu-Sheng; Mo, Chia-Wei; Huang, Chu-Ning; Hsu, Shu-Chiung; Lee, Kung-Ta; Liu, Chi-Te

    2014-01-01

    Several Rhodopseudomonas palustris strains have been isolated from rice paddy fields in Taiwan by combining the Winogradsky column method and molecular marker detection. These isolates were initially screened by employing seed germination and seedling vigor assays to evaluate their potential as inoculants. To fulfill the demand in the present farming system for reducing the application of chemical fertilizers, we assessed the plant growth-promoting effects of the R. palustris YSC3, YSC4, and PS3 inoculants on Brassica rapa chinensis (Chinese cabbage) cultivated under a half quantity of fertilizer. The results obtained showed that supplementation with approximately 4.0×106 CFU g−1 soil of the PS3 inoculant at half the amount of fertilizer consistently produced the same plant growth potential as 100% fertility, and also increased the nitrogen use efficiency of the applied fertilizer nutrients. Furthermore, we noted that the plant growth-promotion rate elicited by PS3 was markedly higher with old seeds than with new seeds, suggesting it has the potential to boost the development of seedlings that were germinated from carry-over seeds of poor quality. These beneficial traits suggest that the PS3 isolate may serve as a potential PGPR inoculant for integrated nutrient management in agriculture. PMID:25130882

  2. Correlation between bio-hydrogen production and polyhydroxybutyrate (PHB) synthesis by Rhodopseudomonas palustris WP3-5.

    PubMed

    Wu, Siang Chen; Liou, Syuan Zih; Lee, Chi Mei

    2012-06-01

    The aim of this study was to determine the competition between H(2) production and polyhydroxybutyrate (PHB) accumulation of Rhodopseudomonas palustris WP3-5 when grown on six different substrates. From the results, strain WP3-5 can utilize acetate, propionate, malate, and lactate to produce H(2) but can only synthesize PHB on acetate and propionate. The substrate conversion efficiency (SCE) on acetate and propionate increased significantly after the maximum PHB content was achieved, illustrating a competition for reducing power when PHB synthesis occurred. However, when strain WP3-5 was cultivated at suboptimal pH values on acetate, the synthesized PHB prevented strain WP3-5 from the stress of the inappropriate pH and retained H(2) producing efficiency as at optimal pH value. Consequently, although PHB synthesis does compete with H(2) production in R. palustris WP3-5, it is still conducive to H(2) production when strain WP3-5 is in a stressful condition.

  3. Isolation and partial characterization of Rhodopseudomonas sphaeroides mutants defective in the regulation of ribulose bisphosphate carboxylase/oxygenase.

    PubMed

    Weaver, K E; Tabita, F R

    1983-11-01

    Several mutants of Rhodopseudomonas sphaeroides defective in the derepression of the enzyme ribulose 1,5-bisphosphate carboxylase have been isolated by using the unstable Tn5 vectors pJB4JI and pRK340. Transpositional insertion mutants obtained with pJB4JI were demonstrated to be incapable of increasing ribulose 1,5-bisphosphate carboxylase/oxygenase levels when grown on butyrate-bicarbonate medium or under conditions of carbon starvation, whereas the wild-type strain increased activity four- to eightfold. When the wild-type strain was starved for carbon in the presence of chloramphenicol, no derepression was observed. Crude extracts from mutant and wild-type strains had distinct and consistent differences in protein content as observed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Chromatographic evidence indicated that mutants were defective in the regulation of only one of the two forms of ribulose 1,5-bisphosphate carboxylase/oxygenase synthesized by R. sphaeroides.

  4. Isolation and preliminary characterization of two forms of ribulose 1,5-bisphosphate carboxylase from Rhodopseudomonas capsulata.

    PubMed

    Gibson, J L; Tabita, F R

    1977-12-01

    The presence of two distinct forms of ribulose 1,5-bisphosphate carboxylase has been demonstrated in extracts of Rhodopseudomonas capsulata, similar to the form I (peak I) and form II (peak II) carboxylases previously described from R. sphaeroides (J. Gibson and F. R. Tabita, J. Biol. Chem 252:943-949, 1977). The two activities, separated by diethylaminoethyl-cellulose chromatography, were shown to be of different molecular size after assay on polyacrylamide gels. The higher-molecular-weight carboxylase from R. capsulata was designated form I-C, whereas the smaller enzyme was designated form II-C. Catalytic studies revealed significant differences between the two enzymes in response to pH and the effector 6-phosphogluconate. Immunological studies with antisera directed against the carboxylases from R. sphaeroides demonstrated antigenic differences between the two R. capsulata enzymes; cross-reactivity was observed only between R. sphaeroides anti-form II serum and the corresponding R. capsulata enzyme, form II-C.

  5. Forms of rare earth elements' sorption by quartz and goethite in the presence of bacteria Rhodopseudomonas palustris

    NASA Astrophysics Data System (ADS)

    Perelomov, L. V.; Perelomova, I. V.; Yoshida, S.

    2009-12-01

    The adsorption of a mixture of 16 isotopes of 14 rare earth elements (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu) present in the initial solution in equal concentrations by quartz and goethite in the presence of bacteria Rhodopseudomonas palustris was studied under different acidity conditions. The solution pH was apparently the leading factor in the interaction of rare earth ions with the surface of mineral and biological sorbents. These interactions were controlled by electrostatic forces in acid (pH 4) and neutral (pH 7) solutions; the precipitation of elements from the solution was the predominant mechanism under alkaline conditions (pH 9). Microorganisms affected the adsorption of lanthanides by quartz in the entire pH range under study, especially at pH 7. In the presence of bacteria, the adsorption of the elements studied by goethite increased in an acid solution, remained unchanged under neutral conditions, and slightly decreased under alkaline conditions. Microorganisms increased the concentration of nonexchangeable forms of the elements adsorbed on the surface of quartz and goethite, which could be due to the formation of low-soluble complexes of rare earth elements with organic substances produced by bacteria.

  6. Growth characteristics of Rhodopseudomonas palustris cultured outdoors, in an underwater tubular photobioreactor, and investigation on photosynthetic efficiency.

    PubMed

    Carlozzi, Pietro; Pushparaj, Benjamin; Degl'Innocenti, Alessandro; Capperucci, Antonella

    2006-12-01

    The underwater tubular photobioreactor is a fully controlled outdoor system to study photosynthetic bacteria. Before growing bacteria cells outdoors, two modified van Niel medium (vN-A, vN-B) were tested under artificial light. During exponential growth, the specific growth rates were 0.0416 and 0.0434 h(-1), respectively; vN-B was chosen for outdoor experiments. The growth behavior of Rhodopseudomonas palustris was investigated under a natural light-dark cycle (sunrise-sunset, 15L/9D) and a forced light-dark cycle (9:00-19:00, 10L/14D). Relationships between solar radiations, daily growth rates, and biomass output rates were also investigated. After determining the elemental biomass molar composition and its combustion heat, some trends of photosynthetic efficiency (PE) were obtained over daylight. The PE trends were always of the oscillatory type, with the exception of that achieved at low biomass concentration. Under a natural light/dark cycle, the maximum PE (11.2%) was attained at sunset, while under a forced light/dark cycle, the highest PE (8.5%) was achieved in the morning. Three initial biomass concentrations were investigated (0.65, 1.01, and 1.54 g l(-1)). The stoichiometric equation for bacteria cells indicated that 87.7% of the carbon of acetic acid was converted to biomass and only 12.3% was lost as CO(2).

  7. Thermodynamics of loop formation in the denatured state of rhodopseudomonas palustris cytochrome c': scaling exponents and the reconciliation problem.

    PubMed

    Rao, K Sudhindra; Tzul, Franco O; Christian, Arwen K; Gordon, Tia N; Bowler, Bruce E

    2009-10-09

    The observation that denatured proteins yield scaling exponents, nu, consistent with random-coil behavior and yet can also have pockets of residual or nonrandom structure has been termed the "reconciliation problem". To provide greater insight into the denatured state of a foldable sequence, we have measured histidine-heme loop formation equilibria in the denatured state of a class II c-type cytochrome, cytochrome c' from Rhodopseudomonas palustris. We have prepared a series of variants that provide His-heme loop stabilities, pK(loop)(His), for loop sizes ranging from 10 to 111 residues at intervals of 7 to 11 residues along the sequence of the protein. We observe a scaling exponent for loop formation, nu(3), of 2.5+/-0.3. Theoretical values for nu(3) range from 1.8 to 2.4; thus, the observed nu(3) is consistent with random-coil behavior. However, in contrast to data for loop formation as a function of loop size obtained with peptides of homogeneous sequence, we observe considerable scatter about the linear dependence of loop stability on loop size. Thus, foldable sequences behave very differently from homogeneous peptide sequences. The observed scatter suggests that there is considerable variation in the conformational properties along the backbone of a foldable sequence, consistent with alternating compact and extended regions. With regard to the reconciliation problem, it is evident that a scaling exponent consistent with a random coil is necessary but not sufficient to demonstrate random-coil behavior.

  8. The light-induced carotenoid absorbance changes in Rhodopseudomonas sphaeroides: an analysis and interpretation of the band shifts.

    PubMed

    Symons, M; Swysen, C; Sybesma, C

    1977-12-23

    An analysis has been made of the spectrum of the carotenoid absorption band shift generated by continuous illumination of chromatophores of the GlC-mutant of Rhodopseudomonas sphaeroides at room temperature by means of three computer programs. There appears to be at least two pools of the same carotenoid, only one of which, comprising about 20% of the total carotenoid content, is responsible for the light-induced absorbance changes. The 'remaining' pool absorbs at wavelengths which were about 5 nm lower than those at which the 'changing' pool absorbs. This difference in absorption wavelength could indicate that the two pools are influenced differently by permanent local electric fields. The electrochromic origin of the absorbance changes has been demonstrated directly; the isosbestic points of the absorption difference spectrum move to shorter wavelengths upon lowering of the light-induced electric field. Band shifts up to 1.7 nm were observed. A comparison of the light-induced absorbance changes with a KCl-valinomycin-induced diffusion potential has been used to calibrate the electrochromic shifts. The calibration value appeared to be 137 +/- 6 mV per nm shift.

  9. Isolation and characterization of the pigment-protein complexes of Rhodopseudomonas sphaeroides by lithium dodecyl sulfate/polyacrylamide gel electrophoresis.

    PubMed

    Broglie, R M; Hunter, C N; Delepelaire, P; Niederman, R A; Chua, N H; Clayton, R K

    1980-01-01

    When purified photosynthetic membranes from Rhodopseudomonas sphaeroides were treated with lithium dodecyl sulfate and subjected to polyacrylamide gel electrophoresis at 4 degrees C, up to 11 pigment-protein complexes were resolved. Absorption spectra revealed that the smallest complex contained reaction center pigments and the others contained the antenna components B850 and B875 in various proportions. Of these antenna complexes, the largest was almost entirely B850 and the smallest contained only B875. After solubilization at 100 degrees C and electrophoresis on polyacrylamide gradient gels, the B850 complex gave rise to two polypeptide components migrating with apparent Mr of 10,000 and 8000, whereas with the B875 complex, two components were observed with apparent Mr of 12,000 and 8000. The reaction center complex gave rise to only the 24 and 21 kilodalton polypeptide subunits. Fluorescence emission spectra showed maxima at 872 and 902 nm for B850 and B875, respectively. Analyses of bacteriochlorophyll a and carotenoids indicated that, in the B875 complex, two molecules of each of these pigments are associated with the two polypeptides. The associations of B850 and B875 in large and small complexes obtained by lithium dodecyl sulfate treatment are consistent with models of their organization within the membrane.

  10. On the extent of localization of the energized membrane state in chromatophores from Rhodopseudomonas capsulata N22.

    PubMed Central

    Hitchens, G D; Kell, D B

    1982-01-01

    1. The principle of the double-inhibitor titration method for assessing competing models of electron transport phosphorylation is expounded. 2. This principle is applied to photophosphorylation by chromatophores from Rhodopseudomonas capsulata N22. 3. It is found that, in contrast to the predictions of the chemiosmotic coupling model, free energy transfer is confined to individual electron transport chain and ATP synthase complexes. 4. This conclusion is not weakened by arguments concerning, the degree of uncoupling in the native chromatophore preparation or the relative number of electron transport chain and ATP synthase complexes present. 5. Photophosphorylation is completely inhibited by the uncoupler SF 6847 at a concentration corresponding to 0.31 molecules per electron transport chain. 6. The apparent paradox is solved by the proposal, consistent with the available evidence on the mode of action of uncouplers, that uncoupler binding causes a co-operative conformation transition in the chromatophore membrane, which leads to uncoupling and which is not present in the absence of uncoupler. PMID:7150247

  11. Control of 5-aminolaevulinate synthetase activity in Rhodopseudomonas spheroides. The purification and properties of an endogenous activator of the enzyme

    PubMed Central

    Neuberger, Albert; Sandy, John D.; Tait, George H.

    1973-01-01

    1. A low-molecular-weight activator of 5-aminolaevulinate synthetase was detected in extracts of Rhodopseudomonas spheroides. The compound activates the enzyme extracted from oxygenated semi-anaerobically grown organisms by a factor of 6–8. 2. The activator was extensively purified, but owing to the exceedingly small amounts that could be extracted in the active form its structure was not determined. 3. The activator contains an acetylatable amino group; it is more stable at acid than at alkaline pH values; it is stable to treatment with I2–KI or potassium ferricyanide, but irreversibly inactivated by Na2S2O4 or NaBH4. 4. The chromatographic, electrophoretic, chemical and stability properties of the activator are similar to those of pteridines; purified activator preparations contain pteridines, as shown by their fluorescence spectrum. This does not, however, constitute an identification of the activator. 5. The activator enhances the activity of crude and partially purified enzyme and does not appear to require other endogenous factors or a supply of air to produce activation. Activation of the purified enzyme, however, requires the presence of either pyridoxal phosphate or sodium succinate. In the absence of both these factors the activator produces a time- and temperature-dependent decay of activity. PMID:4544405

  12. Structure-guided expansion of the substrate range of methylmalonyl coenzyme A synthetase (MatB) of Rhodopseudomonas palustris.

    PubMed

    Crosby, Heidi A; Rank, Katherine C; Rayment, Ivan; Escalante-Semerena, Jorge C

    2012-09-01

    Malonyl coenzyme A (malonyl-CoA) and methylmalonyl-CoA are two of the most commonly used extender units for polyketide biosynthesis and are utilized to synthesize a vast array of pharmaceutically relevant products with antibacterial, antiparasitic, anticholesterol, anticancer, antifungal, and immunosuppressive properties. Heterologous hosts used for polyketide production such as Escherichia coli often do not produce significant amounts of methylmalonyl-CoA, however, requiring the introduction of other pathways for the generation of this important building block. Recently, the bacterial malonyl-CoA synthetase class of enzymes has been utilized to generate malonyl-CoA and methylmalonyl-CoA directly from malonate and methylmalonate. We demonstrate that in the purple photosynthetic bacterium Rhodopseudomonas palustris, MatB (RpMatB) acts as a methylmalonyl-CoA synthetase and is required for growth on methylmalonate. We report the apo (1.7-Å resolution) and ATP-bound (2.0-Å resolution) structure and kinetic analysis of RpMatB, which shows similar activities for both malonate and methylmalonate, making it an ideal enzyme for heterologous polyketide biosynthesis. Additionally, rational, structure-based mutagenesis of the active site of RpMatB led to substantially higher activity with ethylmalonate and butylmalonate, demonstrating that this enzyme is a prime target for expanded substrate specificity.

  13. Electrochromic absorbance changes of photosynthetic pigments in Rhodopseudomonas sphaeroides. I. Stimulation by secondary electron transport at low temperature.

    PubMed

    de Grooth, B G; Amesz, J

    1977-11-17

    Light-induced absorbance changes were measured at temperatures between --30 and --55 degrees C in chromatophores of Rhodopseudomonas sphaeroides. Absorbance changes due to photooxidation of reaction center bacteriochlorophyll (P-870) were accompanied by a red shift of the absorption bands of a carotenoid. The red shift was inhibited by gramicidin D. The kinetics of P-870 indicated electron transport from the "primary" to a secondary electron acceptor. This electron transport was slowed down by lowering the temperature or increasing the pH of the suspension. Electron transport from soluble cytochrome c to P-870+ occurred in less purified chromatophore preparations. This electron transport was accompanied by a relatively large increase of the carotenoid absorbance change. This agrees with the hypothesis that P-870 is located inside the membrane, so that an additional membrane potential is generated upon transfer of an electron from cytochrome to P-870+. A strong stimulation of the carotenoid changes (more than 10-fold in some experiments) and pronounced band shifts of bacteriochlorophyll B-850 were observed upon illumination in the presence of artifical donor-acceptor systems. Reduced N-methylphenazonium methosulphate (PMS) and N,N,N',N'-tetramethyl-p-phenylene-diamine (TMPD) were fairly efficient donors, whereas endogenous ubiquinone and oxidized PMS acted as secondary acceptor. These results indicate the generation of large membrane potentials at low temperature, caused by sustained electron transport across the chromatophore membrane. The artificial probe, merocyanine MC-V did not show electrochromic band shifts at low temperature.

  14. Isolation and Characterization of a Purple Non-Sulfur Photosynthetic Bacterium Rhodopseudomonas faecalis Strain A from Swine Sewage Wastewater.

    PubMed

    Wei, Hongyi; Okunishi, Suguru; Yoshikawa, Takeshi; Kamei, Yuto; Maeda, Hiroto

    2016-01-01

    A purple non-sulfur photosynthetic bacterium (PNSB), PSB Strain A was isolated from swine sewage wastewater. Phylogenetic analysis revealed that PSB Strain A was most closely related to Rhodopseudomonas faecalis. Growth of the isolate under anaerobic-light conditions with a variety of carbon sources was investigated. Both PSB Strain A and the standard strain showed good growth with acetic acid, propionic acid, and n-butyric acid at a concentration of 20 mM. At the high concentration of 200 mM, PSB Strain A showed better growth in pyruvate, acetate, propionate, succinate and malate. By applying PSB Strain A to treat swine sewage wastewater, the concentration of VFAs, which were acetic acid and propionic acid, decreased from 158.0 mM to 120.2±2.9 mM, and 14.9 mM to 9.3±0.9 mM, respectively, after 216-h incubation. After 330-h incubation, the concentrations of TOC and ammonia nitrogen dropped from 4508.0 mg/L to 3104.0±451.5 mg/L, and 629.7 mg/L to 424.1±7.4 mg/L, respectively. The isolated PSB Strain A showed almost the same efficiency compared with the standard strain on the removal of VFAs and TOC. The results suggest the possibility of using the isolated strain to treat swine sewage wastewater.

  15. Control of 5-aminolaevulinate synthetase activity in Rhodopseudomonas spheroides. The purification and properties of an endogenous activator of the enzyme.

    PubMed

    Neuberger, A; Sandy, J D; Tait, G H

    1973-11-01

    1. A low-molecular-weight activator of 5-aminolaevulinate synthetase was detected in extracts of Rhodopseudomonas spheroides. The compound activates the enzyme extracted from oxygenated semi-anaerobically grown organisms by a factor of 6-8. 2. The activator was extensively purified, but owing to the exceedingly small amounts that could be extracted in the active form its structure was not determined. 3. The activator contains an acetylatable amino group; it is more stable at acid than at alkaline pH values; it is stable to treatment with I(2)-KI or potassium ferricyanide, but irreversibly inactivated by Na(2)S(2)O(4) or NaBH(4). 4. The chromatographic, electrophoretic, chemical and stability properties of the activator are similar to those of pteridines; purified activator preparations contain pteridines, as shown by their fluorescence spectrum. This does not, however, constitute an identification of the activator. 5. The activator enhances the activity of crude and partially purified enzyme and does not appear to require other endogenous factors or a supply of air to produce activation. Activation of the purified enzyme, however, requires the presence of either pyridoxal phosphate or sodium succinate. In the absence of both these factors the activator produces a time- and temperature-dependent decay of activity.

  16. Metabolic engineering of Rhodopseudomonas palustris for the obligate reduction of n-butyrate to n-butanol.

    PubMed

    Doud, Devin F R; Holmes, Eric C; Richter, Hanno; Molitor, Bastian; Jander, Georg; Angenent, Largus T

    2017-01-01

    Rhodopseudomonas palustris is a versatile microbe that encounters an innate redox imbalance while growing photoheterotrophically with reduced substrates. The resulting excess in reducing equivalents, together with ATP from photosynthesis, could be utilized to drive a wide range of bioconversions. The objective of this study was to genetically modify R. palustris to provide a pathway to reduce n-butyrate into n-butanol for maintaining redox balance. Here, we constructed and expressed a plasmid-based pathway for n-butanol production from Clostridium acetobutylicum ATCC 824 in R. palustris. We maintained the environmental conditions in such a way that this pathway functioned as the obligate route to re-oxidize excess reducing equivalents, resulting in an innate selection pressure. The engineered strain of R. palustris grew under otherwise restrictive redox conditions and achieved concentrations of 1.5 mM n-butanol at a production rate of 0.03 g L(-1) day(-1) and a selectivity (i.e., products compared to the consumed substrate) of close to 40%. Since the theoretical maximum selectivity is 45%, the engineered strain converted close to its maximum selectivity. The innate redox imbalance of R. palustris can be used to drive the reduction of n-butyrate into n-butanol after expression of a plasmid-based enzyme from a butanol-producing Clostridium strain.

  17. Identification, isolation, and sequence of the reaction center protein genes of the photosynthetic purple bacterium Rhodopseudomonas capsulata

    SciTech Connect

    Hearst, J.E.

    1984-07-01

    Reaction centers in photosynthetic membranes are the centers to which electronic excitation due to light absorption is transferred. This excitation brings about a charge separation between a bacteriochlorophyll molecule and two quinone molecules which ultimately leads to the formation of a hydroquinone. The reduced hydroquinone is then utilized to produce a proton gradient across the membrane and ultimately to produce ATP. We have focused our interest on the structure of the reaction center in the photosynthetic purple bacterium, Rhodopseudomonas capsulata, with the intention of establishing a detailed understanding of these first chemical steps in the natural fixation of sunlight. The methods used to identify and isolate the genes for the three reaction center subunits, L, M, and H, in Rps. capsulata are outlined. These genes have then been sequenced, and the sequences analyzed in detail for their similarity with sequences of comparable proteins from more advanced photosynthetic bacteria such as Anabena, from algae such as Euglena and Chlamydomonas, and from higher plants such as amaranthus, soybean, tobacco and spinach. Homology was found which has been tentatively interpreted to be in the region of quinone binding in all of these reaction centers. There is growing optimism that there will be substantial structural similarity between the reaction centers of the purple bacteria and those of photosystem II in higher plants. This conclusion is important because the x-ray crystal structures of several of the purple bacteria reaction center complexes are presently being worked on and will ultimately be solved.

  18. Promoting effects of a single Rhodopseudomonas palustris inoculant on plant growth by Brassica rapa chinensis under low fertilizer input.

    PubMed

    Wong, Wai-Tak; Tseng, Ching-Han; Hsu, Shu-Hua; Lur, Huu-Sheng; Mo, Chia-Wei; Huang, Chu-Ning; Hsu, Shu-Chiung; Lee, Kung-Ta; Liu, Chi-Te

    2014-09-17

    Several Rhodopseudomonas palustris strains have been isolated from rice paddy fields in Taiwan by combining the Winogradsky column method and molecular marker detection. These isolates were initially screened by employing seed germination and seedling vigor assays to evaluate their potential as inoculants. To fulfill the demand in the present farming system for reducing the application of chemical fertilizers, we assessed the plant growth-promoting effects of the R. palustris YSC3, YSC4, and PS3 inoculants on Brassica rapa chinensis (Chinese cabbage) cultivated under a half quantity of fertilizer. The results obtained showed that supplementation with approximately 4.0×10(6) CFU g(-1) soil of the PS3 inoculant at half the amount of fertilizer consistently produced the same plant growth potential as 100% fertility, and also increased the nitrogen use efficiency of the applied fertilizer nutrients. Furthermore, we noted that the plant growth-promotion rate elicited by PS3 was markedly higher with old seeds than with new seeds, suggesting it has the potential to boost the development of seedlings that were germinated from carry-over seeds of poor quality. These beneficial traits suggest that the PS3 isolate may serve as a potential PGPR inoculant for integrated nutrient management in agriculture.

  19. Rhodopseudomonas sphaeroides lipid A derivatives block in vitro induction of tumor necrosis factor and endotoxin tolerance by smooth lipopolysaccharide and monophosphoryl lipid A.

    PubMed Central

    Henricson, B E; Perera, P Y; Qureshi, N; Takayama, K; Vogel, S N

    1992-01-01

    Rhodopseudomonas (Rhodobacter) sphaeroides diphosphoryl lipid A is a relatively inert species of lipid A but has been shown to antagonize the effects of toxic lipopolysaccharide (LPS) both in vivo and in vitro. The antagonist and its monophosphoryl derivative were examined for the ability to block tumor necrosis factor synthesis and reverse tolerance induction in vitro in macrophage cultures stimulated with bioactive preparations of smooth LPS, rough LPS, diphosphoryl lipid A, and monophosphoryl lipid A. Inhibition of agonist activity and reversal of tolerance by these novel penta-acylated lipid A antagonists provides new insight into macrophage-LPS interactions. PMID:1398939

  20. A two-step fermentation of distillers' grains using Trichoderma viride and Rhodopseudomonas palustris for fish feed.

    PubMed

    Zhang, Jian; Zhang, Wen-Xue; Li, Shun-Zhou; You, Ling; Zhang, Chao; Sun, Chuan-Ze; Liu, Xiao-Bin

    2013-10-01

    It is important to provide added value or to make full use of the co-product of grains from ethanol production. In order to convert distillers' grains into a high-quality feed, the Trichoderma viride and Rhodopseudomonas palustris fermentation were combined and investigated in this study. The T. viride fermentation was carried out in an aerobic fermentation installation in favoring of the growth of the fungi and the degradation of the cellulose, and then the fermentation of R. palustris was performed to increase the content of protein with an anaerobic installation. After the two step fermentations, the true protein content of dried distiller' grains increased from 11.4 to 33.6 % (w/w) (the content of crude protein from 14.5 to 39.7 %), the crude fiber content decreased from 21.3 to 7.6 % (w/w), the crude fat content increased from 5.5 to 7.9 % (w/w), the crude ash decreased from 14.6 to 10.2 % (w/w), the total phosphorus content increased from 0.4 to 1.2 % (w/w), and the water content was 11.8 % (w/w). The dried and fermented grains contain the R. palustris viable count of 5.3 × 10¹¹ CFU/g dry matter. The results may support a new application of an active photosynthetic bacteria fish feed in fisheries industry and offer a reference for the further study of lignocellulosic materials as raw materials converting into high-quality feed.

  1. Activity of the Rhodopseudomonas palustris p-Coumaroyl-Homoserine Lactone-Responsive Transcription Factor RpaR ▿ †

    PubMed Central

    Hirakawa, Hidetada; Oda, Yasuhiro; Phattarasukol, Somsak; Armour, Christopher D.; Castle, John C.; Raymond, Christopher K.; Lappala, Colin R.; Schaefer, Amy L.; Harwood, Caroline S.; Greenberg, E. Peter

    2011-01-01

    The Rhodopseudomonas palustris transcriptional regulator RpaR responds to the RpaI-synthesized quorum-sensing signal p-coumaroyl-homoserine lactone (pC-HSL). Other characterized RpaR homologs respond to fatty acyl-HSLs. We show here that RpaR functions as a transcriptional activator, which binds directly to the rpaI promoter. We developed an RNAseq method that does not require a ribosome depletion step to define a set of transcripts regulated by pC-HSL and RpaR. The transcripts include several noncoding RNAs. A footprint analysis showed that purified His-tagged RpaR (His6-RpaR) binds to an inverted repeat element centered 48.5 bp upstream of the rpaI transcript start site, which we mapped by S1 nuclease protection and primer extension analyses. Although pC-HSL-RpaR bound to rpaI promoter DNA, it did not bind to the promoter regions of a number of RpaR-regulated genes not in the rpaI operon. This indicates that RpaR control of these other genes is indirect. Because the RNAseq analysis allowed us to track transcript strand specificity, we discovered that there is pC-HSL-RpaR-activated antisense transcription of rpaR. These data raise the possibility that this antisense RNA or other RpaR-activated noncoding RNAs mediate the indirect activation of genes in the RpaR-controlled regulon. PMID:21378182

  2. System-wide Studies of N-Lysine Acetylation in Rhodopseudomonas palustris Reveal Substrate Specificity of Protein Acetyltransferases*

    PubMed Central

    Crosby, Heidi A.; Pelletier, Dale A.; Hurst, Gregory B.; Escalante-Semerena, Jorge C.

    2012-01-01

    N-Lysine acetylation is a posttranslational modification that has been well studied in eukaryotes and is likely widespread in prokaryotes as well. The central metabolic enzyme acetyl-CoA synthetase is regulated in both bacteria and eukaryotes by acetylation of a conserved lysine residue in the active site. In the purple photosynthetic α-proteobacterium Rhodopseudomonas palustris, two protein acetyltransferases (RpPat and the newly identified RpKatA) and two deacetylases (RpLdaA and RpSrtN) regulate the activities of AMP-forming acyl-CoA synthetases. In this work, we used LC/MS/MS to identify other proteins regulated by the N-lysine acetylation/deacetylation system of this bacterium. Of the 24 putative acetylated proteins identified, 14 were identified more often in a strain lacking both deacetylases. Nine of these proteins were members of the AMP-forming acyl-CoA synthetase family. RpPat acetylated all nine of the acyl-CoA synthetases identified by this work, and RpLdaA deacetylated eight of them. In all cases, acetylation occurred at the conserved lysine residue in the active site, and acetylation decreased activity of the enzymes by >70%. Our results show that many different AMP-forming acyl-CoA synthetases are regulated by N-lysine acetylation. Five non-acyl-CoA synthetases were identified as possibly acetylated, including glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and Rpa1177, a putative 4-oxalocrotonate tautomerase. Neither RpPat nor RpKatA acetylated either of these proteins in vitro. It has been reported that Salmonella enterica Pat (SePat) can acetylate a number of metabolic enzymes, including GAPDH, but we were unable to confirm this claim, suggesting that the substrate range of SePat is not as broad as suggested previously. PMID:22416131

  3. H2 metabolism in the photosynthetic bacterium Rhodopseudomonas capsulata: production and utilization of H2 by resting cells.

    PubMed

    Hillmer, P; Gest, H

    1977-02-01

    Photoproduction of H2 and activation of H2 for CO2 reduction (photoreduction) by Rhodopseudomonas capsulata are catalyzed by different enzyme systems. Formation of H2 from organic compounds is mediated by nitrogenase and is nto inhibited by an atmosphere of 99% H2. Cells grown photoheterotrophically on C4 dicarboxylic acids (with glutamate as N source) evolve H2 from the C4 acids and also from lactate and pyruvate; cells grown on C3 carbon sources, however, are inactive with the C4 acids, presumably because they lack inducible transport systems. Ammonia is known to inhibit N2 fixation by photosynthetic bacteria, and it also effectively prevents photoproduction of H2; these effects are due to inhibition and, in part, inactivation of nitrogenase. Biosynthesis of the latter, as measured by both H2 production and acetylene reduction assays, is markedly increased when cells are grown at high light intensity; synthesis of the photoreduction system, on the other hand, is not appreciably influenced by light intensity during photoheterotrophic growth. The photoreduction activity of cells grown on lactate + glutamate (which contain active nitrogenase) is greatly activated by NH4+, but this effect is not observed in cells grown with NH4+ as N source (nitrogenase repressed) or in a Nif- mutant that is unable to produce H2. Lactate, malate, and succinate, which are readily used as growth substrates by R. capsulata and are excellent H donors for photoproduction of H2, abolish photoreduction activity. The physiological significances of this phenomenon and of the reciprocal regulatory effects of NH4+ on H2 production and photoreduction are discussed.

  4. H2 metabolism in the photosynthetic bacterium Rhodopseudomonas capsulata: production and utilization of H2 by resting cells.

    PubMed Central

    Hillmer, P; Gest, H

    1977-01-01

    Photoproduction of H2 and activation of H2 for CO2 reduction (photoreduction) by Rhodopseudomonas capsulata are catalyzed by different enzyme systems. Formation of H2 from organic compounds is mediated by nitrogenase and is nto inhibited by an atmosphere of 99% H2. Cells grown photoheterotrophically on C4 dicarboxylic acids (with glutamate as N source) evolve H2 from the C4 acids and also from lactate and pyruvate; cells grown on C3 carbon sources, however, are inactive with the C4 acids, presumably because they lack inducible transport systems. Ammonia is known to inhibit N2 fixation by photosynthetic bacteria, and it also effectively prevents photoproduction of H2; these effects are due to inhibition and, in part, inactivation of nitrogenase. Biosynthesis of the latter, as measured by both H2 production and acetylene reduction assays, is markedly increased when cells are grown at high light intensity; synthesis of the photoreduction system, on the other hand, is not appreciably influenced by light intensity during photoheterotrophic growth. The photoreduction activity of cells grown on lactate + glutamate (which contain active nitrogenase) is greatly activated by NH4+, but this effect is not observed in cells grown with NH4+ as N source (nitrogenase repressed) or in a Nif- mutant that is unable to produce H2. Lactate, malate, and succinate, which are readily used as growth substrates by R. capsulata and are excellent H donors for photoproduction of H2, abolish photoreduction activity. The physiological significances of this phenomenon and of the reciprocal regulatory effects of NH4+ on H2 production and photoreduction are discussed. PMID:838686

  5. BadR and BadM Proteins Transcriptionally Regulate Two Operons Needed for Anaerobic Benzoate Degradation by Rhodopseudomonas palustris

    PubMed Central

    Hirakawa, Hidetada; Hirakawa, Yuko; Greenberg, E. Peter

    2015-01-01

    The bacterium Rhodopseudomonas palustris grows with the aromatic acid benzoate and the alicyclic acid cyclohexanecarboxylate (CHC) as sole carbon sources. The enzymatic steps in an oxygen-independent pathway for CHC degradation have been elucidated, but it was unknown how the CHC operon (badHI aliAB badK) encoding the enzymes for CHC degradation was regulated. aliA and aliB encode enzymes for the conversion of CHC to cyclohex-1-enecarboxyl–coenzyme A (CHene-CoA). At this point, the pathway for CHC degradation merges with the pathway for anaerobic benzoate degradation, as CHene-CoA is an intermediate in both degradation pathways. Three enzymes, encoded by badK, badH, and badI, prepare and cleave the alicyclic ring of CHene-CoA to yield pimelyl-CoA. Here, we show that the MarR transcription factor family member, BadR, represses transcription of the CHC operon by binding near the transcription start site of badH. 2-Ketocyclohexane-1-carboxyl–CoA, an intermediate of CHC and benzoate degradation, interacts with BadR to abrogate repression. We also present evidence that the transcription factor BadM binds to the promoter of the badDEFGAB (Bad) operon for the anaerobic conversion of benzoate to CHene-CoA to repress its expression. Contrary to previous reports, BadR does not appear to control expression of the Bad operon. These data enhance our view of the transcriptional regulation of anaerobic benzoate degradation by R. palustris. PMID:25888170

  6. Phenotype Fingerprinting Suggests the Involvement of Single-Genotype Consortia in Degradation of Aromatic Compounds by Rhodopseudomonas palustris

    PubMed Central

    Karpinets, Tatiana V.; Pelletier, Dale A.; Pan, Chongle; Uberbacher, Edward C.; Melnichenko, Galina V.; Hettich, Robert L.; Samatova, Nagiza F.

    2009-01-01

    Anaerobic degradation of complex organic compounds by microorganisms is crucial for development of innovative biotechnologies for bioethanol production and for efficient degradation of environmental pollutants. In natural environments, the degradation is usually accomplished by syntrophic consortia comprised of different bacterial species. This strategy allows consortium organisms to reduce efforts required for maintenance of the redox homeostasis at each syntrophic level. Cellular mechanisms that maintain the redox homeostasis during the degradation of aromatic compounds by one organism are not fully understood. Here we present a hypothesis that the metabolically versatile phototrophic bacterium Rhodopseudomonas palustris forms its own syntrophic consortia, when it grows anaerobically on p-coumarate or benzoate as a sole carbon source. We have revealed the consortia from large-scale measurements of mRNA and protein expressions under p-coumarate, benzoate and succinate degrading conditions using a novel computational approach referred as phenotype fingerprinting. In this approach, marker genes for known R. palustris phenotypes are employed to determine the relative expression levels of genes and proteins in aromatics versus non-aromatics degrading condition. Subpopulations of the consortia are inferred from the expression of phenotypes and known metabolic modes of the R. palustris growth. We find that p-coumarate degrading conditions may lead to at least three R. palustris subpopulations utilizing p-coumarate, benzoate, and CO2 and H2. Benzoate degrading conditions may also produce at least three subpopulations utilizing benzoate, CO2 and H2, and N2 and formate. Communication among syntrophs and inter-syntrophic dynamics in each consortium are indicated by up-regulation of transporters and genes involved in the curli formation and chemotaxis. The N2-fixing subpopulation in the benzoate degrading consortium has preferential activation of the vanadium nitrogenase

  7. Phenotype fingerprinting suggests the involvement of single-genotype consortia in degradation of aromatic compounds by Rhodopseudomonas palustris

    SciTech Connect

    Karpinets, Tatiana V; Pelletier, Dale A; Pan, Chongle; Uberbacher, Edward C; Hettich, Robert {Bob} L; Samatova, Nagiza F

    2009-01-01

    Understanding of cellular processes involved in the anaerobic degradation of complex organic compounds by microorganisms is crucial for development of innovative biotechnologies for bioethanol production and for efficient degradation of toxic organic compounds. In natural environment the degradation is usually accomplished by syntrophic consortia comprised of different bacterial species. Here we show that the metabolically versatile phototrophic bacterium Rhodopseudomonas palustris may form its own syntrophic consortia, when it grows anaerobically on p-coumarate or benzoate as a sole carbon source. In the study we reveal the consortia from a comparison of large-scale measurements of mRNA and protein expressions under p-coumarate and benzoate degrading conditions using a novel computational approach referred as phenotype fingerprinting. In this approach marker genes for known R. palustris phenotypes are employed to calculate their expression from the gene and protein expressions in each studied condition. Subpopulations of the consortia are inferred from the expression of phenotypes and known metabolic modes of the R. palustris growth. We find that p-coumarate degrading condition leads to at least three R. palustris subpopulations utilizing p-coumarate, benzoate, and CO2 and H2. Benzoate degrading condition also produces at least three subpopulations utilizing benzoate, CO2 and H2, and N2 and formate. Communication among syntrophs and inter-syntrophic dynamics in each consortium are indicated by up-regulation of transporters and genes involved in the curli formation and chemotaxis. The photoautotrphic subpopulation found in both consortia is characterized by activation of two cbb operons and the uptake hydrogenase system. A specificity of N2-fixing subpopulation in the benzoate degrading consortium is the preferential activation of the vanadium nitrogenase over the molybdenum nitrogenase. The N2-fixing subpopulation in the consortium is confirmed by consumption of

  8. Innovation im Mittelstand am Beispiel Der Senkung Von Mobilitätskosten Durch Schwarmintelligenz"

    NASA Astrophysics Data System (ADS)

    Fischer, Hieronymus

    Die zunehmende Vernetzung von Einzelsystemen im Fahrzeug wird durch den Einsatz weiterer Kommunikationsverbindungen (CAR2X-Kommunikation) zu einer hierarchischen Struktur führen, die den Austausch von Informationen zwischen einer Vielzahl von verteilten heterogenen Subsystemen auf mobilen und stationären Plattformen ermöglicht. Die primären Ziele einer solchen Vernetzung von Cyber-Physical Systems sind die Bereitstellung neuer Dienste im Fahrzeug, die Erhöhung der Verkehrssicherheit sowie die effektive Steuerung der weiter wachsenden Verkehrsströme.

  9. Reduktion von Rissartefakten durch nicht-lineare Registrierung in histologischen Schnittbildern

    NASA Astrophysics Data System (ADS)

    Schubert, Nicole; Pietrzyk, Uwe; Reißel, Martin; Palm, Christoph

    In dieser Arbeit wird ein Verfahren vorgestellt, das Rissartefakte, die in histologischen Rattenhirnschnitten vorkommen können, durch nicht-lineare Registrierung reduziert. Um die Optimierung in der Rissregion zu leiten, wird der Curvature Registrierungsansatz um eine Metrik basierend auf der Segmentierung der Bilder erweitert. Dabei erzielten Registrierungen mit der ausschließlichen Segmentierung des Risses bessere Ergebnisse als Registrierungen mit einer Segmentierung des gesamten Hirnschnitts. Insgesamt zeigt sich eine deutliche Verbesserung in der Rissregion, wobei der verbleibende reduzierte Riss auf die Glatt-heitsbedingungen des Regularisierers zurückzuführen ist.

  10. Deutsch Durch Audio-Visuelle Methode: An Audio-Lingual-Oral Approach to the Teaching of German.

    ERIC Educational Resources Information Center

    Dickinson Public Schools, ND. Instructional Media Center.

    This teaching guide, designed to accompany Chilton's "Deutsch Durch Audio-Visuelle Methode" for German 1 and 2 in a three-year secondary school program, focuses major attention on the operational plan of the program and a student orientation unit. A section on teaching a unit discusses four phases: (1) presentation, (2) explanation, (3)…

  11. Clades of Photosynthetic Bacteria Belonging to the Genus Rhodopseudomonas Show Marked Diversity in Light-Harvesting Antenna Complex Gene Composition and Expression

    DOE PAGES

    Fixen, Kathryn R.; Oda, Yasuhiro; Harwood, Caroline S.; ...

    2015-12-22

    Many photosynthetic bacteria have peripheral light-harvesting (LH) antenna complexes that increase the efficiency of light energy capture. The purple nonsulfur photosynthetic bacteriumRhodopseudomonas palustrisproduces different types of LH complexes under high light intensities (LH2 complex) and low light intensities (LH3 and LH4 complexes). There are multiplepucBAoperons that encode the α and β peptides that make up these complexes. But, low-resolution structures, amino acid similarities between the complexes, and a lack of transcription analysis have made it difficult to determine the contributions of differentpucBAoperons to the composition and function of different LH complexes. It was also unclear how much diversity of LHmore » complexes exists inR. palustrisand affiliated strains. To address this, we undertook an integrative genomics approach using 20 sequenced strains. Gene content analysis revealed that even closely related strains have differences in theirpucBAgene content. Transcriptome analyses of the strains grown under high light and low light revealed that the patterns of expression of thepucBAoperons varied among strains grown under the same conditions. We also found that one set of LH2 complex proteins compensated for the lack of an LH4 complex under low light intensities but not under extremely low light intensities, indicating that there is functional redundancy between some of the LH complexes under certain light intensities. The variation observed in LH gene composition and expression inRhodopseudomonasstrains likely reflects how they have evolved to adapt to light conditions in specific soil and water microenvironments. ImportanceRhodopseudomonas palustrisis a phototrophic purple nonsulfur bacterium that adapts its photosystem to allow growth at a range of light intensities. It does this by adjusting the amount and composition of peripheral light-harvesting (LH) antenna complexes that it synthesizes.Rhodopseudomonasstrains are notable for

  12. 15N electron nuclear double resonance of the primary donor cation radical P+.865 in reaction centers of Rhodopseudomonas sphaeroides: additional evidence for the dimer model.

    PubMed Central

    Lubitz, W; Isaacson, R A; Abresch, E C; Feher, G

    1984-01-01

    Four 15N hyperfine coupling constants, including signs, have been measured by electron nuclear double resonance (ENDOR) and electron nuclear nuclear triple resonance (TRIPLE) for the bacteriochlorophyll a radical cation, BChla+., in vitro and for the light-induced primary donor radical cation, P+.865, in reaction centers of Rhodopseudomonas sphaeroides R-26. A comparison of the data shows that the hyperfine coupling constants have the same sign in both radicals and are, on the average, smaller by a factor of 2 in P+.865. These results provide additional evidence that P+.865 is a bacteriochlorophyll dimer and are in contradiction with the monomer structure of P+.865 recently proposed by O'Malley and Babcock. The reduction factors of the individual 15N couplings, together with the evidence from proton ENDOR data and molecular orbital calculations, indicate a dimer structure in which only two rings (either I and I or III and III) of the bacteriochlorophyll macrocycles overlap. PMID:6096857

  13. Acetate-dependent photoheterotrophic growth and the differential requirement for the Calvin-Benson-Bassham reductive pentose phosphate cycle in Rhodobacter sphaeroides and Rhodopseudomonas palustris.

    PubMed

    Laguna, Rick; Tabita, F Robert; Alber, Birgit E

    2011-02-01

    Rhodobacter sphaeroides ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO)-deletion strain 16 was capable of photoheterotrophic growth with acetate, while Rhodopseudomonas palustris RubisCO-deletion strain 2040 could not grow under these conditions. The reason for this difference lies in the fact that Rba. sphaeroides and Rps. palustris use different pathways for acetate assimilation, the ethylmalonyl-CoA pathway, and glyoxylate-bypass cycle, respectively. The ethylmalonyl-CoA pathway is distinct from the glyoxylate cycle as one molecule of CO(2) and one molecule of HCO(3) (-) per three molecules of acetyl-CoA are co-assimilated to form two malate molecules. The glyoxylate cycle directly converts two acetyl-CoA molecules to malate. Each pathway, therefore, also dictates at what point, CO(2) and reductant are consumed, thereby determining the requirement for the Calvin-Benson-Bassham reductive pentose phosphate cycle.

  14. Metabolic flexibility of the Fe(II)-oxidizing phototropic strain Rhodopseudomonas palustris TIE1 and its potential role in microbial iron cycling

    NASA Astrophysics Data System (ADS)

    Schmidt, C.; Oswald, K.; Melton, E. D.; Kappler, A.

    2012-04-01

    The biogeochemical conversion of iron(II) and iron(III) is widespread in many aquatic and terrestrial environments. In the anoxic regime of soils and sediments the conversion and alternation of the iron redox state is predominantly run by microorganisms that are thought to gain life-sustaining energy by the oxidation and/or reduction of ferrous/ferric components. The spatial arrangement of microbial iron(II) oxidation and iron(III) reduction is largely controlled by the availability of the required electron acceptor and electron donor, as well as the essential source of energy (i.e. light or chemical energy). The physico-chemical patterns of many microbial environments undergo dynamic variations (i.e. diurnal and seasonal changes) as a function of natural external forces (i.e. seasonality, storm events, algae blooms) which strongly affects the local budget of organic carbon and nutrients, as well as the day light penetration. Such fluctuations force microorganisms either to follow the flow of substrate or to switch their metabolism to alternative electron acceptors and/or donors. Different photoferrotrophic bacteria have been shown to be able to grow either on organic (heterotrophic) or inorganic (autotrophic) substrates while exploiting light as their energy source. Within the frame of this study the preference for organic substrates (lactate and acetate) and/or ferrous iron (in simultaneous presence) for photo(ferro)trophic growth of Rhodopseudomonas palustris TIE1 has been investigated in detail. Rates of iron oxidation, acetate/lactate consumption and growth have been followed over time as a function of different lactate to acetate to iron(II) ratios. Additional experiments have been designed to evaluate the potential of Rhodopseudomonas palustris TIE1 to contribute to the redox cycling of iron. TIE1 has been grown in a batch set-up in which the iron(III)-reducing strain Shewanella oneidensis MR1 has been incubated at different ferrihydrite concentrations in

  15. Ionenquelle mit Plasma-Anregung durch Mikrowellen bei Elektronen-Zyklotron-Resonanz

    NASA Astrophysics Data System (ADS)

    Hammer, K.; Weissmantel, C.

    Mit der Mikrowellen-Entladung bei Zyklotron-Resonanz ist eine effektive Plasma-Anregung möglich; es lassen sich Ionisationsgrade um 0,1 in Edel- und Reaktivgasen erreichen. Die Nutzung für Ionenquellen bietet gegenüber der unselbständigen Niederdruck-Bogenentladung eine Reihe von Vorteilen, insbesondere durch den Wegfall der Glühkatode. Es wird eine Breitstrahl-Ionenquelle beschrieben, die bei einer Extraktionsspannung von 1 kV Ionenströme bis zu 150 mA liefert. Die Ionenstromdichte läßt sich über einen Strahldurchmesser von 150 mm weitgehend konstant halten. Damit erfüllt die Mikrowellen-Ionenquelle Forderungen, wie sie beim Einsatz von Ionenstrahlverfahren in der Mikroelektronik gestellt werden.Translated AbstractIon Source with Plasma Generation by Microwaves in Electron Cyclotron ResonanceThe microwave discharge operated at cyclotron resonance allows to achieve an effective plasma generation; degrees of ionization of about 0,1 are feasible. The utilization in ion sources offers compared with non-selfsustained are discharges several advantages, in particular because the hot cathode is emitted. A broad-beam ion source is described which yields ion currents up to 150 mA at an extraction voltage of 1 kV. The ion current density could be maintained nearly constant over a beam diameter of 150 mm. Hence, the microwave ion source is shown to match the requirements for applications of ion beam processes in microelectronics.

  16. Evaluation of the effects of different liquid inoculant formulations on the survival and plant-growth-promoting efficiency of Rhodopseudomonas palustris strain PS3.

    PubMed

    Lee, Sook-Kuan; Lur, Huu-Sheng; Lo, Kai-Jiun; Cheng, Kuan-Chen; Chuang, Chun-Chao; Tang, Shiueh-Jung; Yang, Zhi-Wei; Liu, Chi-Te

    2016-09-01

    Biofertilizers can help improve soil quality, promote crop growth, and sustain soil health. The photosynthetic bacterium Rhodopseudomonas palustris strain PS3 (hereafter, PS3), which was isolated from Taiwanese paddy soil, can not only exert beneficial effects on plant growth but also enhance the efficiency of nutrient uptake from applied fertilizer. To produce this elite microbial isolate for practical use, product development and formulation are needed to permit the maintenance of the high quality of the inoculant during storage. The aim of this study was to select a suitable formulation that improves the survival and maintains the beneficial effects of the PS3 inoculant. Six additives (alginate, polyethylene glycol [PEG], polyvinylpyrrolidone-40 [PVP], glycerol, glucose, and horticultural oil) were used in liquid-based formulations, and their capacities for maintaining PS3 cell viability during storage in low, medium, and high temperature ranges were evaluated. Horticultural oil (0.5 %) was chosen as a potential additive because it could maintain a relatively high population and conferred greater microbial vitality under various storage conditions. Furthermore, the growth-promoting effects exerted on Chinese cabbage by the formulated inoculants were significantly greater than those of the unformulated treatments. The fresh and dry weights of the shoots were significantly increased, by 10-27 and 22-40 %, respectively. Horticultural oil is considered a safe, low-cost, and easy-to-process material, and this formulation would facilitate the practical use of strain PS3 in agriculture.

  17. Preservation of H2 production activity in nanoporous latex coatings of Rhodopseudomonas palustris CGA009 during dry storage at ambient temperatures

    PubMed Central

    Piskorska, M; Soule, T; Gosse, J L; Milliken, C; Flickinger, M C; Smith, G W; Yeager, C M

    2013-01-01

    Summary To assess the applicability of latex cell coatings as an ‘off-the-shelf’ biocatalyst, the effect of osmoprotectants, temperature, humidity and O2 on preservation of H2 production in Rhodopseudomonas palustris coatings was evaluated. Immediately following latex coating coalescence (24 h) and for up to 2 weeks of dry storage, rehydrated coatings containing different osmoprotectants displayed similar rates of H2 production. Beyond 2 weeks of storage, sorbitol-treated coatings lost all H2 production activity, whereas considerable H2 production was still detected in sucrose- and trehalose-stabilized coatings. The relative humidity level at which the coatings were stored had a significant impact on the recovery and subsequent rates of H2 production. After 4 weeks storage under air at 60% humidity, coatings produced only trace amounts of H2 (0–0.1% headspace accumulation), whereas those stored at < 5% humidity retained 27–53% of their H2 production activity after 8 weeks of storage. When stored in argon at < 5% humidity and room temperature, R. palustris coatings retained full H2 production activity for 3 months, implicating oxidative damage as a key factor limiting coating storage. Overall, the results demonstrate that biocatalytic latex coatings are an attractive cell immobilization platform for preservation of bioactivity in the dry state. PMID:23331993

  18. Regulatory Twist and Synergistic Role of Metabolic Coinducer- and Response Regulator-Mediated CbbR-cbbI Interactions in Rhodopseudomonas palustris CGA010

    PubMed Central

    Joshi, Gauri S.; Zianni, Michael; Bobst, Cedric E.

    2013-01-01

    Rhodopseudomonas palustris assimilates CO2 by the Calvin-Benson-Bassham (CBB) reductive pentose phosphate pathway. Most genes required for a functional CBB pathway are clustered into the cbbI and cbbII operons, with the cbbI operon subject to control by a LysR transcriptional activator, CbbR, encoded by cbbR, which is divergently transcribed from the cbbLS genes (encoding form I RubisCO) of the cbbI operon. Juxtaposed between the genes encoding CbbR and CbbLS are genes that encode a three-protein two-component system (CbbRRS system) that functions to modify the ability of CbbR to regulate cbbLS expression. Previous studies indicated that the response regulators, as well as various coinducers (effectors), specifically influence CbbR-promoter interactions. In the current study, it was shown via several experimental approaches that the response regulators and coinducers act synergistically on CbbR to influence cbbLS transcription. Synergistic effects on the formation of specific CbbR-DNA complexes were quantified using surface plasmon resonance (SPR) procedures. Gel mobility shift and DNA footprint analyses further indicated structural changes in the DNA arising from the presence of response regulators and coinducer molecules binding to CbbR. Based on previous studies, and especially emphasized by the current investigation, it is clear that protein complexes influence promoter activity and the cbbLS transcription machinery. PMID:23292778

  19. Purification of L-glutamate-dependent citrate lyase from Clostridium sphenoides and electron microscopic analysis of citrate lyase isolated from Rhodopseudomonas gelatinosa, Streptococcus diacetilactis and C. sphenoides.

    PubMed

    Antranikian, G; Klinner, C; Kümmel, A; Schwanitz, D; Zimmermann, T; Mayer, F; Gottschalk, G

    1982-08-01

    Citrate lyase from Clostridium sphenoides was purified 72-fold with a yield of 11%. In contrast to citrate lyase from other sources the activity of this enzyme was strictly dependent on the presence of L-glutamate. The purified enzyme was only stable in the presence of 150 mM L-glutamate or 7 mM L-glutamate plus glycerol, sucrose or bovine serum albumin. Changes of the L-glutamate pool and of enzyme activity in growing cells of C. sphenoides indicated that citrate lyase activity in this organism was regulated by the intracellular L-glutamate concentration. Citrate lyase isolated from C. sphenoides, Rhodopseudomonas gelatinosa and Streptococcus diacetilactis was investigated by electron microscopy using the negative staining technique. Three different projections of enzyme molecules were observed: 'star' form, 'ring' form and 'triangle' form. In samples from R. gelatinosa and S. diacetilactis, star and ring forms occurred in a ratio of about 1:9. Using the enzyme from S. diacetilactis it was demonstrated that this ratio could be altered in favour of the star form by the addition of citrate or tricarballylate. The triangle form was observed in less than 1% of all evaluated molecules and may represent a transition form. In lyase samples from C. sphenoides there existed a correlation between enzyme activity and the proportion of stars and rings at varying concentrations of L-glutamate.

  20. Spectroscopy on the B850 band of individual light-harvesting 2 complexes of Rhodopseudomonas acidophila. I. Experiments and Monte Carlo simulations.

    PubMed Central

    Ketelaars, M; van Oijen, A M; Matsushita, M; Köhler, J; Schmidt, J; Aartsma, T J

    2001-01-01

    The electronic structure of the circular aggregate of 18 bacteriochlorophyll a (BChl a) molecules responsible for the B850 absorption band of the light-harvesting 2 (LH2) complex of the photosynthetic purple bacterium Rhodopseudomonas acidophila has been studied by measuring fluorescence-excitation spectra of individual complexes at 1.2 K. The spectra reveal several well-resolved bands that are obscured in the single, broad B850 band observed in conventional absorption measurements on bulk samples. They are interpreted consistently in terms of the exciton model for the circular aggregate of BChl a molecules. From the energy separation between the different exciton transitions a reliable value of the intermolecular interaction is obtained. The spectra of the individual complexes allow for a distinction between the intra- and the intercomplex disorder. In addition to the random disorder, a regular modulation of the interaction has to be assumed to account for all the features of the observed spectra. This modulation has a C(2) symmetry, which strongly suggests a structural deformation of the ring into an ellipse. PMID:11222320

  1. Non-growing Rhodopseudomonas palustris Increases the Hydrogen Gas Yield from Acetate by Shifting from the Glyoxylate Shunt to the Tricarboxylic Acid Cycle*

    PubMed Central

    McKinlay, James B.; Oda, Yasuhiro; Rühl, Martin; Posto, Amanda L.; Sauer, Uwe; Harwood, Caroline S.

    2014-01-01

    When starved for nitrogen, non-growing cells of the photosynthetic bacterium Rhodopseudomonas palustris continue to metabolize acetate and produce H2, an important industrial chemical and potential biofuel. The enzyme nitrogenase catalyzes H2 formation. The highest H2 yields are obtained when cells are deprived of N2 and thus use available electrons to synthesize H2 as the exclusive product of nitrogenase. To understand how R. palustris responds metabolically to increase H2 yields when it is starved for N2, and thus not growing, we tracked changes in biomass composition and global transcript levels. In addition to a 3.5-fold higher H2 yield by non-growing cells we also observed an accumulation of polyhydroxybutyrate to over 30% of the dry cell weight. The transcriptome of R. palustris showed down-regulation of biosynthetic processes and up-regulation of nitrogen scavenging mechanisms in response to N2 starvation but gene expression changes did not point to metabolic activities that could generate the reductant necessary to explain the high H2 yield. We therefore tracked 13C-labeled acetate through central metabolic pathways. We found that non-growing cells shifted their metabolism to use the tricarboxylic acid cycle to metabolize acetate in contrast to growing cells, which used the glyoxylate cycle exclusively. This shift enabled cells to more fully oxidize acetate, providing the necessary reducing power to explain the high H2 yield. PMID:24302724

  2. Signaling-State Formation Mechanism of a BLUF Protein PapB from the Purple Bacterium Rhodopseudomonas palustris Studied by Femtosecond Time-Resolved Absorption Spectroscopy.

    PubMed

    Fujisawa, Tomotsumi; Takeuchi, Satoshi; Masuda, Shinji; Tahara, Tahei

    2014-12-26

    We studied the signaling-state formation of a BLUF (blue light using FAD) protein, PapB, from the purple bacterium Rhodopseudomonas palustris, using femtosecond time-resolved absorption spectroscopy. Upon photoexcitation of the dark state, FADH(•) (neutral flavin semiquinone FADH radical) was observed as the intermediate before the formation of the signaling state. The kinetic analysis based on singular value decomposition showed that FADH(•) mediates the signaling-state formation, showing that PapB is the second example of FADH(•)-mediated formation of the signaling state after Slr1694 (M. Gauden et al. Proc. Natl. Acad. Sci. U.S.A. 2006, 103, 10895-10900). The mechanism of the signaling-state formation is discussed on the basis of the comparison between femtosecond time-resolved absorption spectra of the dark state and those obtained by exciting the signaling state. FADH(•) was observed also with excitation of the signaling state, and surprisingly, the kinetics of FADH(•) was indistinguishable from the case of exciting the dark state. This result suggests that the hydrogen bond environment in the signaling state is realized before the formation of FADH(•) in the photocycle of PapB.

  3. Preservation of H 2 production activity in nanoporous latex coatings of Rhodopseudomonas palustris CGA009 during dry storage at ambient temperatures: Preservation of R.palustris latex coatings

    DOE PAGES

    Piskorska, M.; Soule, T.; Gosse, J. L.; ...

    2013-07-21

    To assess the applicability of latex cell coatings as an ‘off-the-shelf’ biocatalyst, the effect of osmoprotectants, temperature, humidity and O2 on preservation of H2 production in Rhodopseudomonas palustris coatings was evaluated. Immediately following latex coating coalescence (24 h) and for up to 2 weeks of dry storage, rehydrated coatings containing different osmoprotectants displayed similar rates of H2 production. Beyond 2 weeks of storage, sorbitol-treated coatings lost all H2 production activity, whereas considerable H2 production was still detected in sucrose- and trehalose-stabilized coatings. We stored the coatings at a relative humidity level which significantly impacts the recovery and subsequent rates ofmore » H2 production. After 4 weeks storage under air at 60% humidity, coatings produced only trace amounts of H2 (0–0.1% headspace accumulation), whereas those stored at < 5% humidity retained 27–53% of their H2 production activity after 8 weeks of storage. Furthermore, when stored in argon at < 5% humidity and room temperature, R. palustris coatings retained full H2 production activity for 3 months, implicating oxidative damage as a key factor limiting coating storage. Ultimately, the results demonstrate that biocatalytic latex coatings are an attractive cell immobilization platform for preservation of bioactivity in the dry state.« less

  4. Structure-Function Studies with the Unique Hexameric Form II Ribulose-1,5-bisphosphate Carboxylase/Oxygenase (Rubisco) from Rhodopseudomonas palustris*

    PubMed Central

    Satagopan, Sriram; Chan, Sum; Perry, L. Jeanne; Tabita, F. Robert

    2014-01-01

    The first x-ray crystal structure has been solved for an activated transition-state analog-bound form II ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco). This enzyme, from Rhodopseudomonas palustris, assembles as a unique hexamer with three pairs of catalytic large subunit homodimers around a central 3-fold symmetry axis. This oligomer arrangement is unique among all known Rubisco structures, including the form II homolog from Rhodospirillum rubrum. The presence of a transition-state analog in the active site locked the activated enzyme in a “closed” conformation and revealed the positions of critical active site residues during catalysis. Functional roles of two form II-specific residues (Ile165 and Met331) near the active site were examined via site-directed mutagenesis. Substitutions at these residues affect function but not the ability of the enzyme to assemble. Random mutagenesis and suppressor selection in a Rubisco deletion strain of Rhodobacter capsulatus identified a residue in the amino terminus of one subunit (Ala47) that compensated for a negative change near the active site of a neighboring subunit. In addition, substitution of the native carboxyl-terminal sequence with the last few dissimilar residues from the related R. rubrum homolog increased the enzyme's kcat for carboxylation. However, replacement of a longer carboxyl-terminal sequence with termini from either a form III or a form I enzyme, which varied both in length and sequence, resulted in complete loss of function. From these studies, it is evident that a number of subtle interactions near the active site and the carboxyl terminus account for functional differences between the different forms of Rubiscos found in nature. PMID:24942737

  5. Biochemical and physiological characterization of a BLUF protein-EAL protein complex involved in blue light-dependent degradation of cyclic diguanylate in the purple bacterium Rhodopseudomonas palustris.

    PubMed

    Kanazawa, Takuya; Ren, Shukun; Maekawa, Mikika; Hasegawa, Koji; Arisaka, Fumio; Hyodo, Mamoru; Hayakawa, Yoshihiro; Ohta, Hiroyuki; Masuda, Shinji

    2010-12-21

    Organisms adapt their physiologies in response to the quality and quantity of environmental light. Members of a recently identified photoreceptor protein family, BLUF domain proteins, use a flavin chromophore to sense blue light. Herein, we report that PapB, which contains a BLUF domain, controls the biofilm formation of the purple photosynthetic bacterium Rhodopseudomonas palustris. Purified PapB undergoes a typical BLUF-type photocycle, and light-excited PapB enhances the phosphodiesterase activity of the EAL domain protein, PapA, which degrades the second messenger, cyclic dimeric GMP (c-di-GMP). PapB directly interacts with PapA in vitro in a light-independent manner and induces a conformational change in the preformed PapA-PapB complex. A PapA-PapB docking simulation, as well as a site-directed mutagenesis study, identified amino acids partially responsible for the interaction between the PapA EAL domain and the two C-terminal α-helices of the PapB BLUF domain. Thus, the conformational change, which involves the C-terminal α-helices, transfers the flavin-sensed blue light signal to PapA. Deletion of papB in R. palustris enhances biofilm formation under high-intensity blue light conditions, indicating that PapB functions as a blue light sensor, which negatively regulates biofilm formation. These results demonstrate that R. palustris can control biofilm formation via a blue light-dependent modulation of its c-di-GMP level by the BLUF domain protein, PapB.

  6. Single-Genotype Syntrophy by Rhodopseudomonas palustris Is Not a Strategy to Aid Redox Balance during Anaerobic Degradation of Lignin Monomers

    PubMed Central

    Doud, Devin F. R.; Angenent, Largus T.

    2016-01-01

    Rhodopseudomonas palustris has emerged as a model microbe for the anaerobic metabolism of p-coumarate, which is an aromatic compound and a primary component of lignin. However, under anaerobic conditions, R. palustris must actively eliminate excess reducing equivalents through a number of known strategies (e.g., CO2 fixation, H2 evolution) to avoid lethal redox imbalance. Others had hypothesized that to ease the burden of this redox imbalance, a clonal population of R. palustris could functionally differentiate into a pseudo-consortium. Within this pseudo-consortium, one sub-population would perform the aromatic moiety degradation into acetate, while the other sub-population would oxidize acetate, resulting in a single-genotype syntrophy through acetate sharing. Here, the objective was to test this hypothesis by utilizing microbial electrochemistry as a research tool with the extracellular-electron-transferring bacterium Geobacter sulfurreducens as a reporter strain replacing the hypothesized acetate-oxidizing sub-population. We used a 2 × 4 experimental design with pure cultures of R. palustris in serum bottles and co-cultures of R. palustris and G. sulfurreducens in bioelectrochemical systems. This experimental design included growth medium with and without bicarbonate to induce non-lethal and lethal redox imbalance conditions, respectively, in R. palustris. Finally, the design also included a mutant strain (NifA*) of R. palustris, which constitutively produces H2, to serve both as a positive control for metabolite secretion (H2) to G. sulfurreducens, and as a non-lethal redox control for without bicarbonate conditions. Our results demonstrate that acetate sharing between different sub-populations of R. palustris does not occur while degrading p-coumarate under either non-lethal or lethal redox imbalance conditions. This work highlights the strength of microbial electrochemistry as a tool for studying microbial syntrophy. PMID:27471497

  7. Transcriptomic Responses of the Interactions between Clostridium cellulovorans 743B and Rhodopseudomonas palustris CGA009 in a Cellulose-Grown Coculture for Enhanced Hydrogen Production

    PubMed Central

    Lu, Hongyuan; Chen, Jiahua; Jia, Yangyang; Cai, Mingwei

    2016-01-01

    ABSTRACT Coculturing dark- and photofermentative bacteria is a promising strategy for enhanced hydrogen (H2) production. In this study, next-generation sequencing was used to query the global transcriptomic responses of an artificial coculture of Clostridium cellulovorans 743B and Rhodopseudomonas palustris CGA009. By analyzing differentially regulated gene expression, we showed that, consistent with the physiological observations of enhanced H2 production and cellulose degradation, the nitrogen fixation genes in R. palustris and the cellulosomal genes in C. cellulovorans were upregulated in cocultures. Unexpectedly, genes related to H2 production in C. cellulovorans were downregulated, suggesting that the enhanced H2 yield was contributed mainly by R. palustris. A number of genes related to biosynthesis of volatile fatty acids (VFAs) in C. cellulovorans were upregulated, and correspondingly, a gene that mediates organic compound catabolism in R. palustris was also upregulated. Interestingly, a number of genes responsible for chemotaxis in R. palustris were upregulated, which might be elicited by the VFA concentration gradient created by C. cellulovorans. In addition, genes responsible for sulfur and thiamine metabolism in C. cellulovorans were downregulated in cocultures, and this could be due to a response to pH changes. A conceptual model illustrating the interactions between the two organisms was constructed based on the transcriptomic results. IMPORTANCE The findings of this study have important biotechnology applications for biohydrogen production using renewable cellulose, which is an industrially and economically important bioenergy process. Since the molecular characteristics of the interactions of a coculture when cellulose is the substrate are still unclear, this work will be of interest to microbiologists seeking to better understand and optimize hydrogen-producing coculture systems. PMID:27208134

  8. 4-hydroxybenzoyl coenzyme A reductase (dehydroxylating) is required for anaerobic degradation of 4-hydroxybenzoate by Rhodopseudomonas palustris and shares features with molybdenum-containing hydroxylases.

    PubMed

    Gibson, J; Dispensa, M; Harwood, C S

    1997-02-01

    The anaerobic degradation of 4-hydroxybenzoate is initiated by the formation of 4-hydroxybenzoyl coenzyme A, with the next step proposed to be a dehydroxylation to benzoyl coenzyme A, the starting compound for a central pathway of aromatic compound ring reduction and cleavage. Three open reading frames, divergently transcribed from the 4-hydroxybenzoate coenzyme A ligase gene, hbaA, were identified and sequenced from the phototrophic bacterium Rhodopseudomonas palustris. These genes, named hbaBCD, specify polypeptides of 17.5, 82.6, and 34.5 kDa, respectively. The deduced amino acid sequences show considerable similarities to a group of hydroxylating enzymes involved in CO, xanthine, and nicotine metabolism that have conserved binding sites for [2Fe-2S] clusters and a molybdenum cofactor. Cassette disruption of the hbaB gene yielded a mutant that was unable to grow anaerobically on 4-hydroxybenzoate but grew normally on benzoate. The hbaB mutant cells did not accumulate [14C]benzoyl coenzyme A during short-term uptake of [14C]4-hydroxybenzoate, but benzoyl coenzyme A was the major radioactive metabolite formed by the wild type. In addition, crude extracts of the mutant failed to convert 4-hydroxybenzoyl coenzyme A to benzoyl coenzyme A. This evidence indicates that the hbaBCD genes encode the subunits of a 4-hydroxybenzoyl coenzyme A reductase (dehydroxylating). The sizes of the specified polypeptides are similar to those reported for 4-hydroxybenzoyl coenzyme A reductase isolated from the denitrifying bacterium Thauera aromatica. The amino acid consensus sequence for a molybdenum cofactor binding site is in HbaC. This cofactor appears to be an essential component because anaerobic growth of R. palustris on 4-hydroxybenzoate, but not on benzoate, was retarded unless 0.1 microM molybdate was added to the medium. Neither tungstate nor vanadate replaced molybdate, and tungstate competitively inhibited growth stimulation by molybdate.

  9. Does the reconstitution of RC-LH1 complexes from Rhodopseudomonas acidophila strain 10050 into a phospholipid bilayer yield the optimum environment for optical spectroscopy?

    PubMed

    Böhm, Paul S; Kunz, Ralf; Southall, June; Cogdell, Richard J; Köhler, Jürgen

    2013-12-05

    We have investigated reaction-center light-harvesting 1 (RC-LH1) complexes from Rhodopseudomonas (Rps.) acidophila in detergent buffer solution and reconstituted into a phospholipid bilayer and compared the results with the outcome of an earlier study conducted on RC-LH1 immobilized in polyvinyl alcohol (PVA). The aim of this study was to test whether the immobilization of the complexes in a PVA matrix might lead to a deterioration of the proteins and thereby limit the accessible information that can be obtained from optical spectroscopy. It has been found that the complexes dissolved in a detergent buffer solution are subject to fast spectral dynamics preventing any meaningful application of single-molecule spectroscopy. In contrast, for the bilayer samples it is revealed that the reconstitution process results in a significantly larger fraction of broken complexes with respect to the preparation of the complexes in a PVA film. Moreover, we find that for the intact complexes the statistics of the key spectral features, such as the spectral separations of the bands and the mutual orientation of their transition-dipole moments, show no variation dependent on using either a bilayer or PVA as a matrix. Given the additional effort involved in the reconstitution process, the lower amount of intact RC-LH1 complexes and, concerning the decisive spectral details, the identical results with respect to embedding the complexes in a PVA matrix, we come to the conclusion that the immobilization of these proteins in a PVA matrix is a good choice for conducting low-temperature experiments on individual light-harvesting complexes.

  10. Reversible Nε-Lysine Acetylation Regulates the Activity of Acyl-CoA Synthetases Involved in Anaerobic Benzoate Catabolism in Rhodopseudomonas palustris

    PubMed Central

    Crosby, Heidi A.; Heiniger, Erin K.; Harwood, Caroline S.; Escalante-Semerena, Jorge C.

    2010-01-01

    Rhodopseudomonas palustris grows photoheterotrophically on aromatic compounds available in aquatic environments rich in plant-derived lignin. Benzoate degradation is regulated at the transcriptional level in R. palustris in response to anoxia and the presence of benzoate and/or benzoyl-CoA (Bz-CoA). Here, we report evidence that anaerobic benzoate catabolism in this bacterium is also regulated at the posttranslational level. In this pathway, benzoate is activated to Bz-CoA by the AMP-forming Bz-CoA synthetase (BadA) enzyme. Mass spectrometry and mutational analysis data indicate that residue Lys512 is critical to BadA activity. Acetylation of Lys512 inactivated BadA; deacetylation reactivated BadA. Likewise, 4-hydroxybenzoyl-CoA (HbaA) and cyclohexanecarboxyl-CoA (AliA) synthetases were also reversibly acetylated. We identified one acetyltransferase that modified BadA, Hba, and AliA in vitro. The acetyltransferase enzyme is homologous to the protein acetyltransferase (Pat) enzyme of Salmonella enterica sv Typhimurium LT2, thus we refer to it as RpPat. RpPat also modified acetyl-CoA (Ac-CoA) synthetase (Acs) from R. palustris. In vivo data indicate that at least two deacetylases reactivate BadAAc. One is SrtN (encoded by srtN, formerly rpa2524), a sirtuin-type NAD+-dependent deacetylase (O-acetyl-ADP-ribose-forming); the other deacetylase is LdaA (encoded by ldaA, for lysine deacetylase A; formerly rpa0954), an acetate-forming protein deacetylase. LdaA reactivated HbaAc and AliAAc in vitro. PMID:20345662

  11. Single-genotype syntrophy by Rhodopseudomonas palustris is not a strategy to aid redox balance during anaerobic degradation of lignin monomers

    DOE PAGES

    Doud, Devin F. R.; Angenent, Largus T.

    2016-07-14

    Rhodopseudomonas palustris has emerged as a model microbe for the anaerobic metabolism of p-coumarate, which is an aromatic compound and a primary component of lignin. However, under an aerobic conditions, R.palustris must actively eliminate excess reducing equivalents through a number of known strategies (e.g., CO2 fixation, H2 evolution) to avoid lethal redox imbalance. Others had hypothesized that to ease the burden of this redox imbalance, a clonal population of R.palustris could functionally differentiate into a pseudo-consortium. Within this pseudo-consortium, one sub-population would perform the aromatic moiety degradation into acetate, while the other sub-population would oxidize acetate, resulting in a single-genotypemore » syntrophy through acetate sharing. Here, the objective was to test this hypothesis by utilizing microbial lelectrochemistry as a research tool with the extrac ellular-electron-transferring bacterium Geobacter sulfurreducens as a reporter strain replacing the hypothesized acetate-oxidizing sub-population. We used a 2×4 experimental design with pure cultures of R. palustris in serum bottles and co-cultures of R. palustris and G.sulfurreducens in bioelectrochemical systems.This experimental design included growth medium with and without bicarbonate to induce non-lethal and lethal redox imbalance conditions, respectively, in R. palustris. Finally, the design also included a mutant strain (NifA*) of R. palustris, which constitutively produces H2, to serve both as a positive control for metabolite secretion (H2) to G. sulfurreducens, and as a non-lethal redox control for without bicarbonate conditions. Our results demonstrate that acetate sharing between different sub-populations of R. palustris does not occur while degrading p-coumarate under either non-lethal or lethal redox imbalance conditions. Furthermore, this work highlights the strength of microbial electrochemistry as a tool for studying microbial syntrophy.« less

  12. The Didactic Model "LdL" (Lernen Durch Lehren) as a Way of Preparing Students for Communication in a Knowledge Society

    ERIC Educational Resources Information Center

    Grzega, Joachim; Schoner, Marion

    2008-01-01

    Based on studies in learning psychology, biology and education, the original technique "Lernen durch Lehren" ("LdL)" (German for "learning by teaching") has been elaborated into a meta-model ("Meta") "LdL" that aims at giving students a platform to acquire the competencies considered necessary for knowledge societies. Ninety-seven former students…

  13. High-throughput transcriptome sequencing analysis provides preliminary insights into the biotransformation mechanism of Rhodopseudomonas palustris treated with alpha-rhamnetin-3-rhamnoside.

    PubMed

    Bi, Lei; Guan, Chun-jie; Yang, Guan-e; Yang, Fei; Yan, Hong-yu; Li, Qing-shan

    2016-04-01

    The purple photosynthetic bacterium Rhodopseudomonas palustris has been widely applied to enhance the therapeutic effects of traditional Chinese medicine using novel biotransformation technology. However, comprehensive studies of the R. palustris biotransformation mechanism are rare. Therefore, investigation of the expression patterns of genes involved in metabolic pathways that are active during the biotransformation process is essential to elucidate this complicated mechanism. To promote further study of the biotransformation of R. palustris, we assembled all R. palustris transcripts using Trinity software and performed differential expression analysis of the resulting unigenes. A total of 9725, 7341 and 10,963 unigenes were obtained by assembling the alpha-rhamnetin-3-rhamnoside-treated R. palustris (RPB) reads, control R. palustris (RPS) reads and combined RPB&RPS reads, respectively. A total of 9971 unigenes assembled from the RPB&RPS reads were mapped to the nr, nt, Swiss-Prot, Gene Ontology (GO), Clusters of Orthologous Groups (COGs) and Kyoto Encyclopedia of Genes and Genomes (KEGG) (E-value <0.00001) databases using BLAST software. A total of 3360 unique differentially expressed genes (DEGs) in RPB versus RPS were identified, among which 922 unigenes were up-regulated and 2438 were down-regulated. The unigenes were mapped to the KEGG database, resulting in the identification of 7676 pathways among all annotated unigenes and 2586 pathways among the DEGs. Some sets of functional unigenes annotated to important metabolic pathways and environmental information processing were differentially expressed between the RPS and RPB samples, including those involved in energy metabolism (18.4% of total DEGs), carbohydrate metabolism (36.0% of total DEGs), ABC transport (6.0% of total DEGs), the two-component system (8.6% of total DEGs), cell motility (4.3% of total DEGs) and the cell cycle (1.5% of total DEGs). We also identified 19 transcripts annotated as hydrolytic

  14. Differential accumulation of form I RubisCO in Rhodopseudomonas palustris CGA010 under photoheterotrophic growth conditions with reduced carbon sources

    SciTech Connect

    Joshi, Gauri S; Romagnoli, Simona; Verberkmoes, Nathan C; Hettich, Robert {Bob} L; Pelletier, Dale A; Tabita, F Robert

    2009-01-01

    Rhodopseudomonas palustris is unique among characterized nonsulfur purple bacteria because of its capacity for anaerobic photoheterotrophic growth using aromatic acids. Like growth with other reduced electron donors, this growth typically requires the presence of bicarbonate/CO{sub 2} or some other added electron acceptor in the growth medium. Proteomic studies indicated that there was specific accumulation of form I ribulose 1, 5-bisphosphate carboxylase/oxygenase (RubisCO) subunit proteins (CbbL and CbbS), as well as the CbbX protein, in cells grown on benzoate without added bicarbonate; such cells used the small amounts of dissolved CO{sub 2} in the medium to support growth. These proteins were not observed in extracts from cells grown in the presence of high levels (10 mM) of added bicarbonate. To confirm the results of the proteomics studies, it was shown that the total RubisCO activity levels were significantly higher (five- to sevenfold higher) in wild-type (CGA010) cells grown on benzoate with a low level (0.5 mM) of added bicarbonate. Immunoblots indicated that the increase in RubisCO activity levels was due to a specific increase in the amount of form I RubisCO (CbbLS) and not in the amount of form II RubisCO (CbbM), which was constitutively expressed. Deletion of the main transcriptional regulator gene, cbbR, resulted in impaired growth on benzoate-containing low-bicarbonate media, and it was established that form I RubisCO synthesis was absolutely and specifically dependent on CbbR. To understand the regulatory role of the CbbRRS two-component system, strains with nonpolar deletions of the cbbRRS genes were grown on benzoate. Distinct from the results obtained with photoautotrophic growth conditions, the results of studies with various CbbRRS mutant strains indicated that this two-component system did not affect the observed enhanced synthesis of form I RubisCO under benzoate growth conditions. These studies indicate that diverse growth conditions

  15. Herbicide-quinone competition in the acceptor complex of photosynthetic reaction centers from Rhodopseudomonas sphaeroides: a bacterial model for PS-II-herbicide activity in plants.

    PubMed

    Stein, R R; Castellvi, A L; Bogacz, J P; Wraight, C A

    1984-01-01

    A select group of herbicides that inhibit photosystem II also act at the acceptor side of the reaction center (RC) from the photosynthetic bacterium Rhodopseudomonas sphaeroides, with much the same relative specificity as in plants. These include the triazines and some phenolic compounds. The proposal that herbicides inhibit the electron transfer from the primary quinone (QA) to the secondary quinone (QB) by competing for the secondary quinone binding site--the B-site--[5], is tested here with terbutryn, the most potent of the triazines. Competition between terbutryn and ubiquinone (Q-10) was observed using the kinetics of the back-reaction as a measure of inhibition. The model includes binding equilibria before and after flash activation. The binding constants for the preflash (dark) equilibria, for reaction centers in 0.14% lauryl dimethylamine-N-oxide (LDAO), were KDi = 0.8 microM terbutryn, KDq = 2 microM Q-10; both are detergent-concentration dependent. After flash activation, binding equilibrium is not fully restored on the time scale of the back-reaction because terbutryn unbinds slowly. This gives rise to biphasic decay kinetics from which koff for terbutryn was estimated to be 3 sec-1. Titrations of the rate of the slow back reaction indicated that the post-flash equilibrium is less sensitive to inhibitor, in a manner that is independent of the much stronger binding of the semiquinone, Q-B, and indicative of a direct effect of the redox state of QA on the affinity of the B-site for ligands. However, the effects on KLi and KDq could not be separated: either KLi greater than KDi or KLq less than KDq. Some triazine-resistant mutants have been isolated and are described. All appear to be herbicide binding site mutants. Whole cells and photosynthetic membrane vesicles (chromatophores) exhibit a 10-50-fold increase in resistance to triazines due, in large part, to an increase in the rate of unbinding (koff). The modifications of the binding site appear to

  16. BadR, a new MarR family member, regulates anaerobic benzoate degradation by Rhodopseudomonas palustris in concert with AadR, an Fnr family member.

    PubMed

    Egland, P G; Harwood, C S

    1999-04-01

    A cluster of genes for the anaerobic degradation of benzoate has been described for the phototrophic bacterium Rhodopseudomonas palustris. Here we provide an initial analysis of the regulation of anaerobic benzoate degradation by examining the contributions of two regulators: a new regulator, BadR, encoded by the benzoate degradation gene cluster, and a previously described regulator, AadR, whose gene lies outside the cluster. Strains with single mutations in either badR or aadR grew slowly on benzoate but were relatively unimpaired in growth on succinate and several intermediates of benzoate degradation. A badR aadR double mutant was completely defective in anaerobic growth on benzoate. Effects of the regulators on transcriptional activation were monitored with an R. palustris strain carrying a chromosomal fusion of 'lacZ to the badE gene of the badDEFG operon. This operon encodes benzoyl-coenzyme A (benzoyl-CoA) reductase, an unusual oxygen-sensitive enzyme that catalyzes the benzene ring reduction reaction that is the rate-limiting step in anaerobic benzoate degradation. Expression of badE::'lacZ was induced 100-fold when cells grown aerobically on succinate were shifted to anaerobic growth on succinate plus benzoate. The aadR gene was required for a 20-fold increase in expression that occurred in response to anaerobiosis, and badR was responsible for a further 5-fold increase in expression that occurred in response to benzoate. Further studies with the badE::'lacZ fusion strain grown with various kinds of aromatic acids indicated that BadR probably responds to benzoyl-CoA acting as an effector molecule. Sequence information indicates that BadR is a member of the MarR family of transcriptional regulators. These studies expand the range of functions regulated by MarR family members to include anaerobic aromatic acid degradation and provide an example of a MarR-type protein that acts as a positive regulator rather than as a negative regulator, as do most Mar

  17. Single-genotype syntrophy by Rhodopseudomonas palustris is not a strategy to aid redox balance during anaerobic degradation of lignin monomers

    SciTech Connect

    Doud, Devin F. R.; Angenent, Largus T.

    2016-07-14

    Rhodopseudomonas palustris has emerged as a model microbe for the anaerobic metabolism of p-coumarate, which is an aromatic compound and a primary component of lignin. However, under an aerobic conditions, R.palustris must actively eliminate excess reducing equivalents through a number of known strategies (e.g., CO2 fixation, H2 evolution) to avoid lethal redox imbalance. Others had hypothesized that to ease the burden of this redox imbalance, a clonal population of R.palustris could functionally differentiate into a pseudo-consortium. Within this pseudo-consortium, one sub-population would perform the aromatic moiety degradation into acetate, while the other sub-population would oxidize acetate, resulting in a single-genotype syntrophy through acetate sharing. Here, the objective was to test this hypothesis by utilizing microbial lelectrochemistry as a research tool with the extrac ellular-electron-transferring bacterium Geobacter sulfurreducens as a reporter strain replacing the hypothesized acetate-oxidizing sub-population. We used a 2×4 experimental design with pure cultures of R. palustris in serum bottles and co-cultures of R. palustris and G.sulfurreducens in bioelectrochemical systems.This experimental design included growth medium with and without bicarbonate to induce non-lethal and lethal redox imbalance conditions, respectively, in R. palustris. Finally, the design also included a mutant strain (NifA*) of R. palustris, which constitutively produces H2, to serve both as a positive control for metabolite secretion (H2) to G. sulfurreducens, and as a non-lethal redox control for without bicarbonate conditions. Our results demonstrate that acetate sharing between different sub-populations of R. palustris does not occur while degrading p-coumarate under either non-lethal or lethal redox imbalance conditions. Furthermore, this work highlights the

  18. Isolation of Rhp-PSP, a member of YER057c/YjgF/UK114 protein family with antiviral properties, from the photosynthetic bacterium Rhodopseudomonas palustris strain JSC-3b.

    PubMed

    Su, Pin; Feng, Tuizi; Zhou, Xuguo; Zhang, Songbai; Zhang, Yu; Cheng, Ju'e; Luo, Yuanhua; Peng, Jing; Zhang, Zhuo; Lu, Xiangyang; Zhang, Deyong; Liu, Yong

    2015-11-04

    Rhodopseudomonas palustris strain JSC-3b isolated from a water canal adjacent to a vegetable field produces a protein that was purified by bioactivity-guided fractionation based on ammonium sulfate precipitation, ion-exchange absorption and size exclusion. The protein was further identified as an endoribonuclease L-PSP (Liver-Perchloric acid-soluble protein) by shotgun mass spectrometry analysis and gene identification, and it is member of YER057c/YjgF/UK114 protein family. Herein, this protein is designated Rhp-PSP. Rhp-PSP exhibited significant inhibitory activities against tobacco mosaic virus (TMV) in vivo and in vitro. To our knowledge, this represents the first report on the antiviral activity of a protein of the YER057c/YjgF/UK114 family and also the first antiviral protein isolated from R. palustris. Our research provides insight into the potential of photosynthetic bacterial resources in biological control of plant virus diseases and sustainable agriculture.

  19. Retrospektive Analyse von Zufallsbefunden, die bei Patienten mit kutanem malignen Malignom durch (18) F-Fluordeoxyglucose-PET/CT erhoben wurden.

    PubMed

    Conrad, Franziska; Winkens, Thomas; Kaatz, Martin; Goetze, Steven; Freesmeyer, Martin

    2016-08-01

    Bei der (18) F-Fluordeoxyglucose-Positronenemissionstomographie/Computertomographie (FDG-PET/CT) ergeben sich häufig Zufallsbefunde. In der vorliegenden Studie konzentrierten wir uns auf mittels FDG-PET/CT erhaltene Zufallsbefunde bei Patienten mit kutanem Melanom und überprüften deren Relevanz hinsichtlich weiterer diagnostischer Maßnahmen und Interventionen. Die Krankenakten von 181 konsekutiven Melanom-Patienten wurden retrospektiv ausgewertet, um das Management von Zufallsbefunden zu dokumentieren. Der Schwerpunkt lag dabei auf den histologischen Befunden. Bei 33 von 181 (18 %) Patienten lagen 39 relevante Zufallsbefunde vor, und zwar im Kolorektalbereich (n = 15 Patienten), in der Schilddrüse (n = 8), der Prostata (n = 2), dem Bewegungsapparat (n = 2), in Lymphknoten (n = 2), der Parotis (n = 1), den Mandeln (n = 1), den Nieren (n = 1) und der Gallenblase (n = 1). Bei 25 Patienten schlossen sich weitere diagnostische Verfahren an, wobei in 21 Fällen ein klinisches Korrelat nachgewiesen wurde. Bei 16 von 21 Patienten ergab sich eine Neoplasie, darunter fünf maligne Läsionen (vier Kolonkarzinome und ein Prostatakarzinom). Die Malignome wurden frühzeitig diagnostiziert und in der Mehrzahl der Fälle erfolgreich entfernt. Der Einsatz der FDG-PET/CT als Routine-Diagnostik wird in den Leitlinien empfohlen und ist indiziert bei malignem Melanom ab Stadium IIC. In dieser Studie wurden auf effektive Weise ansonsten nicht erkannte Krebserkrankungen, insbesondere Kolonkarzinome, detektiert. In den meisten Fällen war eine frühe Intervention möglich. Zufallsbefunde durch FDG-PET/CT sollten, unter Berücksichtigung des Zustands und der Wünsche des Patienten, mit den geeigneten diagnostischen Maßnahmen abgeklärt werden. © 2016 Deutsche Dermatologische Gesellschaft (DDG). Published by John Wiley & Sons Ltd.

  20. Studies of interaction of homo-dimeric ferredoxin-NAD(P)+ oxidoreductases of Bacillus subtilis and Rhodopseudomonas palustris, that are closely related to thioredoxin reductases in amino acid sequence, with ferredoxins and pyridine nucleotide coenzymes.

    PubMed

    Seo, Daisuke; Okabe, Seisuke; Yanase, Mitsuhiro; Kataoka, Kunishige; Sakurai, Takeshi

    2009-04-01

    Ferredoxin-NADP(+) oxidoreductases (FNRs) of Bacillus subtilis (YumC) and Rhodopseudomonas palustris CGA009 (RPA3954) belong to a novel homo-dimeric type of FNR with high amino acid sequence homology to NADPH-thioredoxin reductases. These FNRs were purified from expression constructs in Escherichia coli cells, and their steady-state reactions with [2Fe-2S] type ferredoxins (Fds) from spinach and R. palustris, [4Fe-4S] type Fd from B. subtilis, NAD(P)(+)/NAD(P)H and ferricyanide were studied. From the K(m) and k(cat) values for the diaphorase activity with ferricyanide, it is demonstrated that both FNRs are far more specific for NADPH than for NADH. The UV-visible spectral changes induced by NADP(+) and B. subtilis Fd indicated that both FNRs form a ternary complex with NADP(+) and Fd, and that each of the two ligands decreases the affinities of the others. The steady-state kinetics of NADPH-cytochrome c reduction activity of YumC is consistent with formation of a ternary complex of NADPH and Fd during catalysis. These results indicate that despite their low sequence homology to other FNRs, these enzymes possess high FNR activity but with measurable differences in affinity for different types of Fds as compared to other more conventional FNRs.

  1. Preservation of H2 production activity in nanoporous latex coatings of Rhodopseudomonas palustris CGA009 during dry storage at ambient temperatures: Preservation of R. palustris latex coatings

    SciTech Connect

    Piskorska, M.; Soule, T.; Gosse, J. L.; Milliken, C.; Flickinger, M. C.; Smith, G. W.; Yeager, C. M.

    2013-01-21

    To assess the applicability of latex cell coatings as an ‘off-the-shelf’ biocatalyst, the effect of osmoprotectants, temperature, humidity and O2 on preservation of H2 production in Rhodopseudomonas palustris coatings was evaluated. Immediately following latex coating coalescence (24 h) and for up to 2 weeks of dry storage, rehydrated coatings containing different osmoprotectants displayed similar rates of H2 production. Beyond 2 weeks of storage, sorbitol-treated coatings lost all H2 production activity, whereas considerable H2 production was still detected in sucrose- and trehalose-stabilized coatings. The relative humidity level at which the coatings were stored had a significant impact on the recovery and subsequent rates of H2 production. After 4 weeks storage under air at 60% humidity, coatings produced only trace amounts of H2 (0–0.1% headspace accumulation), whereas those stored at < 5% humidity retained 27–53% of their H2 production activity after 8 weeks of storage. In conWhen stored in argon at < 5% humidity and room temperature, R. palustris coatings retained full H2 production activity for 3 months, implicating oxidative damage as a key factor limiting coating storage. Overall, the results demonstrate that biocatalytic latex coatings are an attractive cell immobilization platform for preservation of bioactivity in the dry state.

  2. Preservation of H 2 production activity in nanoporous latex coatings of Rhodopseudomonas palustris CGA009 during dry storage at ambient temperatures: Preservation of R.palustris latex coatings

    SciTech Connect

    Piskorska, M.; Soule, T.; Gosse, J. L.; Milliken, C.; Flickinger, M. C.; Smith, G. W.; Yeager, C. M.

    2013-07-21

    To assess the applicability of latex cell coatings as an ‘off-the-shelf’ biocatalyst, the effect of osmoprotectants, temperature, humidity and O2 on preservation of H2 production in Rhodopseudomonas palustris coatings was evaluated. Immediately following latex coating coalescence (24 h) and for up to 2 weeks of dry storage, rehydrated coatings containing different osmoprotectants displayed similar rates of H2 production. Beyond 2 weeks of storage, sorbitol-treated coatings lost all H2 production activity, whereas considerable H2 production was still detected in sucrose- and trehalose-stabilized coatings. We stored the coatings at a relative humidity level which significantly impacts the recovery and subsequent rates of H2 production. After 4 weeks storage under air at 60% humidity, coatings produced only trace amounts of H2 (0–0.1% headspace accumulation), whereas those stored at < 5% humidity retained 27–53% of their H2 production activity after 8 weeks of storage. Furthermore, when stored in argon at < 5% humidity and room temperature, R. palustris coatings retained full H2 production activity for 3 months, implicating oxidative damage as a key factor limiting coating storage. Ultimately, the results demonstrate that biocatalytic latex coatings are an attractive cell immobilization platform for preservation of bioactivity in the dry state.

  3. Isolation of Rhp-PSP, a member of YER057c/YjgF/UK114 protein family with antiviral properties, from the photosynthetic bacterium Rhodopseudomonas palustris strain JSC-3b

    PubMed Central

    Su, Pin; Feng, Tuizi; Zhou, Xuguo; Zhang, Songbai; Zhang, Yu; Cheng, Ju’e; Luo, Yuanhua; Peng, Jing; Zhang, Zhuo; Lu, Xiangyang; Zhang, Deyong; Liu, Yong

    2015-01-01

    Rhodopseudomonas palustris strain JSC-3b isolated from a water canal adjacent to a vegetable field produces a protein that was purified by bioactivity-guided fractionation based on ammonium sulfate precipitation, ion-exchange absorption and size exclusion. The protein was further identified as an endoribonuclease L-PSP (Liver-Perchloric acid-soluble protein) by shotgun mass spectrometry analysis and gene identification, and it is member of YER057c/YjgF/UK114 protein family. Herein, this protein is designated Rhp-PSP. Rhp-PSP exhibited significant inhibitory activities against tobacco mosaic virus (TMV) in vivo and in vitro. To our knowledge, this represents the first report on the antiviral activity of a protein of the YER057c/YjgF/UK114 family and also the first antiviral protein isolated from R. palustris. Our research provides insight into the potential of photosynthetic bacterial resources in biological control of plant virus diseases and sustainable agriculture. PMID:26530252

  4. Unterstützung der IT-Service-Management-Prozesse an der Technischen Universität München durch eine Configuration-Management-Database

    NASA Astrophysics Data System (ADS)

    Knittl, Silvia

    Hochschulprozesse in Lehre und Verwaltung erfordern durch die steigende Integration und IT-Unterstützung ein sogenanntes Business Alignment der IT und damit auch ein professionelleres IT-Service-Management (ITSM). Die IT Infrastructure Library (ITIL) mit ihrer Beschreibung von in der Praxis bewährten Prozessen hat sich zum de-facto Standard im ITSM etabliert. Ein solcher Prozess ist das Konfigurationsmanagement. Es bildet die IT-Infrastruktur als Konfigurationselemente und deren Beziehungen in einem Werkzeug, genannt Configuration Management Database (CMDB), ab und unterstützt so das ITSM. Dieser Bericht beschreibt die Erfahrungen mit der prototypischen Einführung einer CMDB an der Technischen Universität München.

  5. A Novel Three-Protein Two-Component System Provides a Regulatory Twist on an Established Circuit To Modulate Expression of the cbbI Region of Rhodopseudomonas palustris CGA010

    PubMed Central

    Romagnoli, Simona; Tabita, F. Robert

    2006-01-01

    A novel two-component system has been identified in the cbbI region of the nonsulfur purple photosynthetic bacterium Rhodopseudomonas palustris. Genes encoding this system, here designated cbbRRS, are juxtaposed between the divergently transcribed transcription activator gene, cbbR, and the form I ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) genes, cbbLS. The three genes of the cbbRRS system represent a variation of the well-known two-component signal transduction systems, as there are a transmembrane hybrid sensor kinase and two response regulators, with no apparent DNA binding domain associated with any of the three proteins encoded by these genes. In this study, we showed that the membrane-bound full-length kinase undergoes autophosphorylation and transfers phosphate to both response regulators. A soluble, truncated version of the kinase was subsequently prepared and found to catalyze phosphorylation of response regulator 1 but not response regulator 2, implying that conformational changes and/or sequence-specific regions of the kinase are important for discriminating between the two response regulators. Analyses indicated that a complex network of control of gene expression must occur, with CbbR required for the expression of the cbbLS genes but dispensable for the synthesis of form II RubisCO (encoded by cbbM). The CbbRRS proteins specifically affected the activity and accumulation of form I RubisCO (CbbLS), as revealed by analyses of nonpolar, unmarked gene deletions. A tentative model of regulation suggested that changes in the phosphotransfer activity of the sensor kinase, possibly in response to a redox metabolic signal, cause modulation of the activity and synthesis of form I RubisCO. PMID:16585739

  6. A comparison of the unfolding and dissociation of the large ribosome subunits from Rhodopseudomonas spheroides N.C.I.B. 8253 and Escherichia coli M.R.E. 600.

    PubMed

    Robinson, A; Sykes, J

    1973-08-01

    1. The behaviour of the large ribosomal subunit from Rhodopseudomonas spheroides (45S) has been compared with the 50S ribosome from Escherichia coli M.R.E. 600 (and E. coli M.R.E. 162) during unfolding by removal of Mg(2+) and detachment of ribosomal proteins by high univalent cation concentrations. The extent to which these processes are reversible with these ribosomes has also been examined. 2. The R. spheroides 45S ribosome unfolds relatively slowly but then gives rise directly to two ribonucleoprotein particles (16.6S and 13.7S); the former contains the intact primary structure of the 16.25S rRNA species and the latter the 15.00S rRNA species of the original ribosome. No detectable protein loss occurs during unfolding. The E. coli ribosome unfolds via a series of discrete intermediates to a single, unfolded ribonucleoprotein unit (19.1S) containing the 23S rRNA and all the protein of the original ribosome. 3. The two unfolded R. spheroides ribonucleoproteins did not recombine when the original conditions were restored but each simply assumed a more compact configuration. Similar treatments reversed the unfolding of the E. coli 50S ribosomes; replacement of Mg(2+) caused the refolding of the initial products of unfolding and in the presence of Ni(2+) the completely unfolded species (19.1S) again sedimented at the same rate as the original ribosomes (44S). 4. Ribosomal proteins (25%) were dissociated from R. spheroides 45S ribosomes by dialysis against a solution with a Na(+)/Mg(2+) ratio of 250:1. During this process two core particles were formed (21.2S and 14.2S) and the primary structures of the two original rRNA species were conserved. This dissociation was not reversed. With E. coli 50S approximately 15% of the original ribosomal protein was dissociated, a single 37.6S core particle was formed, the 23S rRNA remained intact and the ribosomal proteins would reassociate with the core particle to give a 50S ribosome. 5. The ribonuclease activities in R

  7. Herausforderungen durch die deutsche Wiedervereinigung

    NASA Astrophysics Data System (ADS)

    Stäglin, Reiner

    Die Wiedervereinigung stellte auch die Statistik vor große Aufgaben. Die als Organ der staatlichen Planung staatsnah orientierte Statistik der DDR musste auf das zur Neutralität und wissenschaftlichen Unabhängigkeit verpflichtete System der Bundesrepublik umgestellt werden. Ebenso verlangten die Universitäten eine Neuorientierung. Die Deutsche Statistische Gesellschaft hat sich vor allem dreier Aufgaben mit großem Engagement, aber auch mit Bedachtsamkeit angenommen: Aufnahme und Integration der Statistiker aus den neuen Bundesländern in die Gesellschaft, Begleitung der Neuausrichtung des Faches Statistik an deren Hochschulen und Sicherung sowie Nutzung von Datenbeständen der ehemaligen DDR.

  8. Isolation and characterization of photosynthetic reaction centers from Rhodopseudomonas capsulata and Rhodopseudomonas sphaeroides

    SciTech Connect

    Worland, S.T.

    1984-09-01

    Reaction centers were isolated by affinity chromatography on equine cytochrome C. Peripheral proteins were removed with 0.05% LDAO. Absorption and EPR spectra and bleaching assays indicate that the reaction centers retained their electron donors and acceptors in the native environment. Three reaction center polypeptides were isolated and submitted for amino-terminal sequence determination. By comparing these sequences to those deduced from DNA, it was established that the M and L subunits are post-translationally modified to remove the aminoterminal Met, whereas the H subunit is not. Inhibition of O/sub 2/ evolution in photosystem II particles from spinach by naphthoquinone derivatives show O/sub 2/ inhibition by bromomethyl and acetoxymethyl derivatives but not with hydroxymethyl derivatives. Inhibition by acetoxymethyl derivatives in irreversible and dependent on illumination suggesting that reduction of the quinone is necessary. Therefore acetoxymethyl derivatives may be useful as suicide reagents for labelling quinone binding sites. Procedures were developed to extract one or both of the quinones present in reaction centers and preserve the integrity of the co-factor binding sites. The H and M subunits were cleaned using furmic acid. Both fragments were isolated from the H subunit, while the larger fragment was isolated from the M subunit. Electrophoretic mobilities of the isolated fragments agrees well with the expected molecular weights. The L subunit was digested with Staphylococcus areus vs protease. The pattern obtained was consistant with the potential sites of cleavage, but it was not possible to assign cleavage sites unambiguously. 112 references, 37 figures, 2 tables.

  9. Deutschunterricht Durch Handeln (Teaching German through Action).

    ERIC Educational Resources Information Center

    Segal, Bertha

    A teaching guide containing 102 elementary to intermediate level German lessons is presented. The lessons are based on the Total Physical Response technique of second language teaching. They follow the stages of first language acquisition: listening, speaking, and reading. Each of the ten units contains a list of new vocabulary words, instructions…

  10. Deutschunterricht Durch Handeln (Teaching German through Action).

    ERIC Educational Resources Information Center

    Segal, Bertha

    A teaching guide containing 102 elementary to intermediate level German lessons is presented. The lessons are based on the Total Physical Response technique of second language teaching. They follow the stages of first language acquisition: listening, speaking, and reading. Each of the ten units contains a list of new vocabulary words, instructions…

  11. Lernen durch Kulturkontakt (Learning through Acculturation).

    ERIC Educational Resources Information Center

    Hesse, Hermann-Gunter

    "Experiences in Acculturation: What Is Being Learned?" is the first of two papers in this volume. It reports on a study of social representations and their development during cultural contacts conducted with beginning teachers who were studied over time and through comparison with cross-culturally competent experts with the aim of…

  12. Landeskunde durch Weinkunde: A Taste of German Culture.

    ERIC Educational Resources Information Center

    Peacock, Dennis E.

    1978-01-01

    Describes a cultural unit centered on German wines. After a series of preparatory lessons showing how the topic touches on geography, history, and social customs, the unit culminated in a wine tasting. (EJS)

  13. Verbesserung der Prozessbedingungen beim Einlippentiefbohren durch unterschiedliche Formen der Vorschubmodulation

    NASA Astrophysics Data System (ADS)

    Eisseler, Rocco

    Das Tiefbohren mit Einlippenwerkzeugen ist bei vielen Anwendungen das Verfahren der ersten Wahl, vor allem wenn kleine und kleinste Bohrungsdurchmesser, ein sehr großes Verhältnis zwischen Bohrtiefe und Durchmesser (l/D) und eine hohe Bearbeitungsqualität gefordert werden. Der erreichbare Durchmesserbereich des Verfahrens liegt zwischen D = 0,5 mm und 40 mm, wobei die möglichen Bohrtiefen von l = 3 x D bis 250 x D reichen. Diese Werte beziehen sich auf das Vollbohren, beim Aufbohren können noch größere Durchmesser erreicht werden [1]. Die erreichbare Oberflächenqualität ist so hoch, dass in den meisten Fällen auf eine nachfolgende Feinbearbeitung verzichtet werden kann.

  14. (Organization and regulation of the genes for nitrogen fixation in Rhodopseudomonas capsulata)

    SciTech Connect

    Not Available

    1991-01-01

    In prior support periods we identified, cloned and sequenced three genes involved in the regulation of nif gene expression in Rhodobacter capsulatus. These were called nifRI, nifR2 and nifR4; they turn out to be homologue of the ntrC, ntrB and ntrA genes of enterobacteria. We subsequently found that mutations in an additional gene, nifR5. render R. capsulatus nif genes constitutive with respect to ammonia. The nifR5 gene was shown to be similar to glnB of enteric bacteria, encoding the regulatory protein PII, and furthering the intersection of the glutamine synthetase adenylylation cascade with the control of nif gene transcription. In pursuit of the mechanism of 0{sub 2} control of nif gene expression, we constructed and analyzed the topology of a small plasmid in R. capsulatus as a function of 0{sub 2} concentration. We also cloned and obtained partial sequence data for two genes encoding the B subunit of DNA gyrase. The nucleotide sequence of the rpoB gene encoding RNA polymerase was nearly completed. A method for isolation of genes expressed differentially, developed for cyanobacteria, was applied successfully to R. capsulatus. Several genes that depend on nifR4 for their transcription were isolated. A transcription start site for a nifA gene was identified and the promoter sequence was analyzed. A physical map of the R calsulatus SB1003 chromosome was prepared, based on pulsed-field electrophoresis of XbaI and AseI fragments and hybridization with a gridded cosmid library, using a device that permits 864 cosmids to be hybridized at one time with a labeled chromosomal fragment.

  15. Light-induced proton gradients and internal volumes in chromatophores of Rhodopseudomonas sphaeroides

    SciTech Connect

    Melandri, B.A.; Mehlhorn, R.J.; Packer, L.

    1984-11-15

    To test the predictions of the chemiosmotic hypothesis, it is essential to have sensitive and accurate measures of the aqueous volume and pH within membrane compartments. One unique feature of the present investigation is the application of electron spin resonance probes to determine internal aqueous volume and pH changes in bacterial chromatophores under virtually identical conditions. Volumes of the chromatophores ranged from 6 to 16 ..mu..l/mg bacteriochlorophyll among different preparations, and were sensitive to the osmolarity of the suspending buffer. pH gradients reached two units in illuminated chromatophores as determined with ESR methods, and increased when KCl and valinomycin were added to the assay. Measurements with the fluorescent dye 9-amino-acridine yielded similar pH gradients, provided that an operational vesicle volume, which corrected for the binding of the dye to the membrane, was used in the calculation. The sensitivity of the ESR method allowed the measurement of pH gradients resulting from only a few light flashes. A plot of pH gradients versus number of flashes was linear up to about 30 flashes, and intercepted the origin. This result is consistent with proton release into the bulk aqueous phase after only a single light flash. This ability to measure small pH gradients offers new opportunities for the study of energy-transducing mechanisms. 21 references, 5 figures.

  16. Organization and regulation of the genes for nitrogen fixation in Rhodopseudomonas capsulata

    SciTech Connect

    Haselkorn, R.

    1989-05-01

    The research carried out over the past two years with DOE support has led to the elucidation of the complete nucleotide sequence of three genes required for the transcription of the genes for nitrogen fixation in Rhodobacter capsulatus. These genes are called nifR1, nifR2 and nifR4 in R. capsulatus. They were found to be homologous to ntrC, ntrB and ntrA in Klebsiella, respectively. Genetic analysis of ammonia-constitutive (NiF{sup c}) mutants of R. capsulatus, isolated using a nifH::lac fusion, showed that ammonia repression involves components of the adenylylation cascade (e.g., the glnB gene) as in Klebsiella. Oxygen control of nif gene expression was linked to the degree of DNA supercoiling by showing that inhibitors of DNA gyrase prevent nif gene expression. Attempts to relate the degree of supercoiling or of gyrase activity in R. capsulatus to the oxygen level have been inconclusive. The gene encoding the DNA gyrase B subunit of R. capsulatus was cloned. The genes encoding the two large subunits of R. Capsulatus RNA polymerase were cloned, mapped and partially sequenced. The nif genes and the glnA gene are being physically mapped on the R. capsulatus chromosome using pulsed field electrophoresis to separate large segments of the bacterial chromosome. A start was made on the purification of R. capsulatus RNA polymerase. A system for expressing genes in R. capsulatus was applied to nifR4; analogous constructions will be made for nifR1, nifR2 and nifA.

  17. Optimization of the yield of dark microaerobic production of hydrogen from lactate by Rhodopseudomonas palustris.

    PubMed

    Lazaro, Carolina Zampol; Hitit, Zeynep Yilmazer; Hallenbeck, Patrick C

    2017-09-08

    Hydrogen yields of dark fermentation are limited due to the need to also produce reduced side products, and photofermentation, an alternative, is limited by the need for light. A relatively new strategy, dark microaerobic fermentation, could potentially overcome both these constraints. Here, application of this strategy demonstrated for the first time significant hydrogen production from lactate by a single organism in the dark. Response surface methodology (RSM) was used to optimize substrate and oxygen concentration as well as inoculum using both (1) regular batch and (2) O2 fed batch cultures. The highest hydrogen yield (HY) was observed under regular batch (1.4±0.1molH2/mollactate) and the highest hydrogen production (HP) (173.5µmolH2) was achieved using O2 fed batch. This study has provided proof of principal for the ability of microaerobic fermentation to drive thermodynamically difficult reactions, such as the conversion of lactate to hydrogen. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. Structure of the response regulator RPA3017 involved in red-light signaling in Rhodopseudomonas palustris.

    PubMed

    Yang, Xuefei; Zeng, Xiaoli; Moffat, Keith; Yang, Xiaojing

    2015-10-01

    Two-component signal transduction is the major signaling mechanism that enables bacteria to survive and thrive in complex environmental conditions. The photosynthetic bacterium R. palustris employs two tandem bacteriophytochromes, RpBphP2 and RpBphP3, to perceive red-light signals that regulate the synthesis of light-harvesting complexes under low-light conditions. Both RpBphP2 and RpBphP3 are photosensory histidine kinases coupled to the same response regulator RPA3017. Together, they constitute a two-component system that converts a red-light signal into a biological signal. In this work, the crystal structure of RPA3017 in the unphosphorylated form at 1.9 Å resolution is presented. This structure reveals a tightly associated dimer arrangement that is conserved among phytochrome-related response regulators. The conserved active-site architecture provides structural insight into the phosphotransfer reaction between RpBphP2/RpBphP3 and RPA3017. Based on structural comparisons and homology modeling, how specific recognition between RpBphP2/RpBphP3 and RPA3017 is achieved at the molecular level is further explored.

  19. Antisense RNA that Affects Rhodopseudomonas palustris Quorum-Sensing Signal Receptor Expression

    DTIC Science & Technology

    2012-01-01

    these molecules . Because asrpaR expression is quorum sensing dependent, we sought to characterize its production and function. We show that asrpaR is...but little is known about the function of these molecules . Because asrpaR expression is quorum sensing dependent, we sought to character- ize its...detection of N-acylhomoserine lactone-type quorum - sensing molecules : Detection of autoinducers in Mesorhizobium huakuii. Appl Environ Microbiol 69: 6949

  20. [Organization and regulation of the genes for nitrogen fixation in Rhodopseudomonas capsulata]. Progress report, [June 5, 1989--June 4, 1991

    SciTech Connect

    Not Available

    1991-12-31

    In prior support periods we identified, cloned and sequenced three genes involved in the regulation of nif gene expression in Rhodobacter capsulatus. These were called nifRI, nifR2 and nifR4; they turn out to be homologue of the ntrC, ntrB and ntrA genes of enterobacteria. We subsequently found that mutations in an additional gene, nifR5. render R. capsulatus nif genes constitutive with respect to ammonia. The nifR5 gene was shown to be similar to glnB of enteric bacteria, encoding the regulatory protein PII, and furthering the intersection of the glutamine synthetase adenylylation cascade with the control of nif gene transcription. In pursuit of the mechanism of 0{sub 2} control of nif gene expression, we constructed and analyzed the topology of a small plasmid in R. capsulatus as a function of 0{sub 2} concentration. We also cloned and obtained partial sequence data for two genes encoding the B subunit of DNA gyrase. The nucleotide sequence of the rpoB gene encoding RNA polymerase was nearly completed. A method for isolation of genes expressed differentially, developed for cyanobacteria, was applied successfully to R. capsulatus. Several genes that depend on nifR4 for their transcription were isolated. A transcription start site for a nifA gene was identified and the promoter sequence was analyzed. A physical map of the R calsulatus SB1003 chromosome was prepared, based on pulsed-field electrophoresis of XbaI and AseI fragments and hybridization with a gridded cosmid library, using a device that permits 864 cosmids to be hybridized at one time with a labeled chromosomal fragment.

  1. System-wide Studies of N-Lysine Acetylation in Rhodopseudomonas palustris Reveals Substrate Specificity of Protein Acetyltransferases

    SciTech Connect

    Crosby, Heidi A; Pelletier, Dale A; Hurst, Gregory {Greg} B; Escalante-Semerena, Jorge C

    2012-01-01

    Background: Protein acetylation is widespread in prokaryotes. Results: Six new acyl-CoA synthetases whose activities are controlled by acetylation were identified, and their substrate preference established. A new protein acetyltransferase was also identified and its substrate specificity determined. Conclusion: Protein acetyltransferases acetylate a conserved lysine residue in protein substrates. Significance: The R. palustris Pat enzyme specifically acetylates AMP-forming acyl-CoA synthetases and regulates fatty acid metabolism.

  2. The NMR solution structure and function of RPA3313: a putative ribosomal transport protein from Rhodopseudomonas palustris.

    PubMed

    Catazaro, Jonathan; Lowe, Austin J; Cerny, Ronald L; Powers, Robert

    2017-01-01

    Protein function elucidation often relies heavily on amino acid sequence analysis and other bioinformatics approaches. The reliance is extended to structure homology modeling for ligand docking and protein-protein interaction mapping. However, sequence analysis of RPA3313 exposes a large, unannotated class of hypothetical proteins mostly from the Rhizobiales order. In the absence of sequence and structure information, further functional elucidation of this class of proteins has been significantly hindered. A high quality NMR structure of RPA3313 reveals that the protein forms a novel split ββαβ fold with a conserved ligand binding pocket between the first β-strand and the N-terminus of the α-helix. Conserved residue analysis and protein-protein interaction prediction analyses reveal multiple protein binding sites and conserved functional residues. Results of a mass spectrometry proteomic analysis strongly point toward interaction with the ribosome and its subunits. The combined structural and proteomic analyses suggest that RPA3313 by itself or in a larger complex may assist in the transportation of substrates to or from the ribosome for further processing. Proteins 2016; 85:93-102. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  3. The exploration of monochromatic near-infrared LED improved anoxygenic photosynthetic bacteria Rhodopseudomonas sp. for wastewater treatment.

    PubMed

    Qi, Xiang; Ren, Yiwei; Tian, Enling; Wang, Xingzu

    2017-10-01

    The future wastewater treatment requires high-efficiency and energy-saving technology. Anoxygenic photosynthetic bacteria (APB) is deemed as an eco-friendly microorganism, which could be employed in wastewater treatment. Here, monochromatic near-infrared (MNIR) light emitting diode (LED) was used, and three key factors (light quality, light intensity and photoperiod) of it were analyzed by a response surface methodology (RSM) in APB wastewater treatment. The results showed that light quality was the biggest impact factor in APB wastewater treatment, and nearly 58.07% of NH4(+)-N and 70.62% of chemical oxygen demand (COD) could be removed based on 46.4% of that theoretically possible. The light quality's study revealed that APB had the highest NH4(+)-N and COD removal, biomass production, and bacteriochlorophyll a production with 850nm IR LED. Moreover, the application of optimal MNIR LED could not only save energy, but also avoid algae bloom of photo-bioreactors (PBR). Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Hydrogen production by Rhodopseudomonas palustris WP 3-5 in a serial photobioreactor fed with hydrogen fermentation effluent.

    PubMed

    Lee, Chi-Mei; Hung, Guo-Jan; Yang, Chu-Fang

    2011-09-01

    In this study, a lab-scale serial photobioreactor composed of three column reactors was constructed and continuously operated to investigate several parameters influencing photohydrogen production when using the synthetic wastewater and the anaerobic hydrogen fermentation effluents as the influents. The results indicated that better hydrogen production rate was obtained when the serial photobioreactor was operated under cellular recycling at a short HRT of 8h. The serial photobioreactor maintained high hydrogen content ca. 80% in the produced gas and 0.4× dilution ratio was the suitable ratio for hydrogen production. When the photobioreactor fed with the real wastewater (Effluent 1) containing 100 mg/L NH4Cl, Column 1 reactor successfully reduced ammonia concentration to about 60 mg/L for cell synthesis, resulting in a steady hydrogen production in the following two column reactors. The average hydrogen production rate was 205 mL-H2/L/d.

  5. Organization and regulation of the genes for nitrogen fixation in Rhodopseudomonas capsulata: Progress report, June 5, 1987-June 4, 1988

    SciTech Connect

    Haselkorn, R.

    1988-02-01

    We have cloned a number of fragments of DNA containing genes necessary for nitrogen fixation from the photosynthetic bacterium Rhodobacter capsulatus. The nif genes are locally clustered but the clusters are on non-neighboring DNA restriction fragments. We sought to determine the physical linkage of these fragments, to determine their relationship with the corresponding nif genes of Klebsiella, and to determine the nucleotide sequence of some of the fragments. So far we have identified six or seven regulatory genes among these, using a nifH::lac fusion. Four of the regulatory genes are required for expression of nifH. Two of these, nifR1 and nifR2, have sequences homologous to ntrC and ntrB of enteric bacteria. A third, nifR4, has sequence homology, in the C-terminal region, to the ntrA genes of Rhizobium and Klebsiella. Constitutive expression of nifR4 in R. capsulatus, from a plasmid clone, complemented a nifR4 chromosomal mutant but not a nifR1 mutant. Moreover, both oxygen and ammonia regulation of nitrogenase were maintained under these conditions. These results are consistent with a model requiring both nifR1 and nifR4 for nitrogenase gene expression; they rule out our earlier suggestion that nifR1 is needed only to turn on nifR4. Current efforts are focused on the purification of RNA polymerase and the products of nifR1, nifR2, and nifR4 to study nif gene transcription in vitro, particularly with the goal of determining the role of DNA supercoiling in transcription.

  6. Durch Raum und Zeit reisen - Eine Theorie gibt Antworten auf alte Fragen

    NASA Astrophysics Data System (ADS)

    Sonne, Bernd; Weiß, Reinhard

    2013-07-01

    Im Rahmen der Relativitätstheorie, sei es die spezielle oder auch allgemeine, kommt man zwangsläufig auf die Fragestellung, ob Zeitreisen möglich sind oder nicht. Es gibt darüber sehr viele Veröffentlichungen, da dieses Thema offensichtlich viele Leute beschäftigt: Naturwissenschaftler, Philosophen, Filmautoren. Wir wollen hier nur einige grundlegende Fragestellungen aufgreifen: Kann man in die Zukunft reisen? Gibt es Reisen mit Überlichtgeschwindigkeit? Wie sieht es aus mit Reisen in die Vergangenheit? Wir unterschieden dabei zwischen mathematischen, physikalischen und technischen Lösungen, die Zeitreisen entweder erlauben oder unmöglich machen.

  7. Vorhersage des Krankheitsverlaufes von leichten kognitiven Beeinträchtigungen durch automatisierte MRT Morphometrie

    NASA Astrophysics Data System (ADS)

    Fritzsche, Klaus H.; Schlindwein, Sarah; Stieltjes, Bram; Essig, Marco; Meinzer, Hans-Peter

    Die leichte kognitive Beeinträchtigung (LKB) gilt als Anzeichen für ein erhöhtes Risiko der Entwicklung einer Alzheimerdemenz. Eine fundierte klinische Prognose für den Krankheitsverlauf kann aber bis dato nicht gegeben werden. Das Ziel dieser Arbeit besteht darin, eine möglichst präzise Vorhersage mittels automatisierter Morphometrie des Hippokampus im MRT-Bild zu treffen. In einer Studie mit 18 Probanden mit LKB wurde eine Prädiktionsgenauigkeit für die Entwicklung einer späteren Demenz von 83.3% erzielt. Eine manuelle Vergleichsmethode erreichte mit 55.6% Trefferquote keine signifikante Vorhersagegenauigkeit. Das automatische Verfahren erfüllt viele wichtige Voraussetzungen für den routinemäßigen klinischen Einsatz mit dem Potential, die klinische Vorhersage des Krankheitsverlaufes bei der LKB zu verbessern.

  8. Zweiwegintegration durch zweisprachige Bildung? Ergebnisse aus der Staatlichen Europa-Schule Berlin

    NASA Astrophysics Data System (ADS)

    Meier, Gabriela

    2012-06-01

    While there is no simple recipe of how to respond to the multitude of languages present in many European schools, this article presents a promising alternative to monolingual education. The focus is on Staatliche Europa-Schule Berlin (SESB), a two-way immersion (TWI) model that unites children whose mother tongue is German with children whose mother tongue is another locally spoken language in one class and teaches them together in two languages. Thus in this model, offered by 17 primary schools and 13 secondary schools in Berlin, pupils learn in two languages from and with each other. Based on a largely quantitative, quasi-experimental study with 603 students, evidence is provided that there are a number of peace-linguistic benefits that can promote two-way social integration, besides fostering personal and societal multilingualism. This suggests that TWI education as practised in Berlin could serve as an educational model for other multilingual parts of Europe.

  9. Einblicke in "Genderism" im Schulischen Verhalten durch subjektive Reflexivitat (Insights into "Genderism" in School Behavior).

    ERIC Educational Resources Information Center

    Faulstich-Wieland; Guting, Damaris; Ebsen, Silke

    2001-01-01

    Explores gender construction through school interactions. Views gender as a socially produced category by analyzing various theoretical approaches. Develops the genderism of school conduct using two examples from German instruction stating that confusion with sexual orientation arises through the deconstruction of the assumed role and active…

  10. Pyritoxidationsprozesse im cretazischen Emschermergel infolge von aeroben Bedingungen durch den Emscherumbau

    NASA Astrophysics Data System (ADS)

    Droste, Björn; Wisotzky, Frank

    2015-09-01

    Due to the restoration of the Emscher river system, large amounts of the Emschermergel, a Cretaceous sediment containing significant amounts of carbonate and pyrite, will be released from its anoxic state. The oxidation of pyrite results in the release of protons, iron and sulfate. In order to evaluate the impact of the reaction products, extensive laboratory investigations were carried out. The methodology can detect pyrite content in the range of magnitude of the Rhenish lignite mining area (average 0.21 wt.% Pyritic-S). The formation of a naturally-occurring weathering horizon could also be detected. Under laboratory conditions, further oxidation of the weathered laboratory samples could be observed. Column experiments show significant release of sulfate at high concentrations. Hydrochemical modelling and acid-base accounting show neutralization of the free protons by the effective carbonate buffer in the sediment.

  11. Verminderte Tiefbrunnenergiebigkeit durch Versandung und Versinterung bei Veränderung der Grundwasserchemie

    NASA Astrophysics Data System (ADS)

    Knuth, Christoph; Wisotzky, Frank; Becke, Norbert

    2017-01-01

    In three deep wells of a water works in the Lower Rhine Valley (Germany) decreasing well yield has been observed. To investigate the reasons for this decline, solids analysis (microscopy, Cinorg measurements, XRD-, SEM-analysis) was completed and hydrogeochemical calculations were carried out. The samples examined from the bottom of the wells indicate both hydromechanical entry of sand from the aquifer into the well, and formation of incrustations in the form of calcite within the well. The water analysis results show that almost all measured ion concentrations have increased over the past 10 years, which indicates a general change of the hydrochemical conditions of the aquifer. Hydrogeochemical models suggest that oversaturation exists regarding the mineral phases iron hydroxide and calcium carbonate, and therefore the formation of incrustations is possible.

  12. Approximation dreidimensionaler Oberflächenmodelle der Lippen-Kiefer-Gaumen-Region durch aktive Polygonnetze

    NASA Astrophysics Data System (ADS)

    Weichert, Frank; Ewerlin, Christoph; Büttner, Christian; Shamaa, Ali; Landes, Constantin; Linder, Roland; Wagner, Mathias

    In dieser Arbeit wird ein Verfahren zur Rekonstruktion eines dreidimensionalen Oberflächenmodells aus Serienschnitten vorgestellt, die sich von Lippen-Kiefer-Gaumenspalten (kurz LKG) ableiten und insbesondere die in der chirurgischen Behandlung relevanten medizinischen Strukturen berücksichtigen. Die Intention ist, ein aktives Polygonnetz (deformierbares Oberflächennetz) zur Rekonstruktion der Struktur zu verwenden. Initial wird ein Netzprototyp als grobe Approximation der Struktur erstellt und dann mithilfe eines Gradient Vector Flow (GVF)-Kraftfeldes deformiert. Inhärenter Aspekt der Deformation ist die Beachtung eines resultierenden überschneidungsfreien Oberflächennetzes. Die rekonstruierte Oberfläche eignet sich aufgrund ausgezeichneter Eigenschaften als Eingabe für eine Kräftesimulation mittels Finite-Elemente-Methoden.

  13. Kosteneffiziente Honbearbeitung durch intelligente und flexible Verknüpfung von autarken Honzentren

    NASA Astrophysics Data System (ADS)

    Roth, Günther

    Die Planungsabteilungen in der Automobilindustrie werden vor immer größere Herausforderungen gestsellt. Der zur Verfügung stehende Zeitraum zu einer seriensicheren Umsetzung der entwicklungs- und produktionstechnischen Forderungen wird von Projekt zu Projekt kürzer. Aufgrund des hohen Wettbewerbsdrucks und daraus resultierenden erforderlichen Kostenoptimierungen, die schnelleren Timeto-market-und Innovationszyklen und die vermeintlich zur Kundenbindung erforderlichen, kaum mehr überschaubaren Diversifizierungen in den Modellpaletten lassen den Planungshorizont immer kürzer werden. Die zu beschaffenden Fertigungsanlagen sollen aber in den nächsten 8-12 Jahren all die Varianten produzieren können, die heute nur teilweise oder noch gar nicht bekannt sind.

  14. Verminderte Tiefbrunnenergiebigkeit durch Versandung und Versinterung bei Veränderung der Grundwasserchemie

    NASA Astrophysics Data System (ADS)

    Knuth, Christoph; Wisotzky, Frank; Becke, Norbert

    2017-03-01

    In three deep wells of a water works in the Lower Rhine Valley (Germany) decreasing well yield has been observed. To investigate the reasons for this decline, solids analysis (microscopy, Cinorg measurements, XRD-, SEM-analysis) was completed and hydrogeochemical calculations were carried out. The samples examined from the bottom of the wells indicate both hydromechanical entry of sand from the aquifer into the well, and formation of incrustations in the form of calcite within the well. The water analysis results show that almost all measured ion concentrations have increased over the past 10 years, which indicates a general change of the hydrochemical conditions of the aquifer. Hydrogeochemical models suggest that oversaturation exists regarding the mineral phases iron hydroxide and calcium carbonate, and therefore the formation of incrustations is possible.

  15. The importance of the benzoic acid carboxylate moiety for substrate recognition by CYP199A4 from Rhodopseudomonas palustris HaA2.

    PubMed

    Coleman, Tom; Chao, Rebecca R; De Voss, James J; Bell, Stephen G

    2016-06-01

    The cytochrome P450 enzyme CYP199A4 can efficiently demethylate 4-methoxybenzoic acid. The substrate is positioned in the enzyme active site with the methoxy group ideally positioned for demethylation. This occurs through interactions of hydrophobic benzene ring with aromatic phenylalanine residues and the charged carboxylate group with polar and basic amino acids. In vitro substrate binding and kinetic turnover assays coupled with HPLC and GC-MS analysis and whole-cell oxidation turnovers. Modification of the carboxylate group to an amide or aldehyde resulted in substrate binding, as judged by the almost total shift of the spin state to the high-spin form, but binding was three orders of magnitude weaker. Changing the carboxylate to phenol alcohol, ketone, ester and nitro groups and boronic, sulfinic and sulfonic acids resulted in a dramatic reduction in the binding affinity. Even phenylacetic acids were mediocre substrates for CYP199A4, despite maintaining a carboxylate group. The weaker binding of all of these substrates results in lower levels of turnover activity and product formation compared to 4-methoxybenzoic acid. Substrate binding to CYP199A4 is tightly regulated by interactions between the 4-methoxybenzoic acid and the amino acids in the active site. The benzoic acid carboxylate moiety is critical for optimal substrate binding and turnover activity with CYP199A4. An understanding of how the CYP199A4 enzyme has evolved to be highly selective for para-substituted benzoic acids. This provides valuable insight into how other, as yet structurally uncharacterised, monooxygenase enzymes may bind benzoic acid substrates. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. Störungen des Betriebs geothermischer Anlagen durch mikrobielle Stoffwechselprozesse und Erfolg von Gegenmaßnahmen

    NASA Astrophysics Data System (ADS)

    Würdemann, Hilke; Westphal, Anke; Kleyböcker, Anne; Miethling-Graff, Rona; Teitz, Sebastian; Kasina, Monika; Seibt, Andrea; Wolfgramm, Markus; Eichinger, Florian; Lerm, Stephanie

    2016-06-01

    In the context of geothermal systems, biofilms can influence mineral formation and material resistance against corrosion. In three geothermal plants with different salinity and temperature, organisms of the sulfur cycle have contributed to process failures. On the cold side of a heat store, the increased diversity and abundance of sulfate reducing bacteria (SRB) revealed their participation in corrosion processes and their contribution to a decline in injection efficiency. In all plants, a temporary ingress of oxygen or nitrate led to an increased abundance of sulfur oxidizing bacteria (SOB) that might have accelerated corrosion. In addition, the increase in SOB abundance led to filter clogging in a cold store. Based on their role in microbial-induced corrosion (MIC), changes in the abundance of SOB and SRB may indicate the cause of failure. Measures to control microbial growth, mineral deposits and corrosion, such as temporary increases in temperature, acidification, and addition of hydrogen peroxide (H2O2) and nitrate, were evaluated.

  17. Entwicklung neuer Uebungsformen durch die Einbeziehung des Mediums Fernsehen (Development of New Types of Exercises through the Use of Television)

    ERIC Educational Resources Information Center

    Eggers, Dietrich

    1975-01-01

    Discusses the use of television in university-preparatory schools. The exercises are supplementary to "Deutsch 2000" (M. Hueber, Munich), and deal with land and culture. Three short films are presented, for use in free comment. Examples of grammar, vocabulary and dictation exercises are given. (Text is in German.) (IFS/WGA)

  18. Bestimmung der Wärmeleitfähigkeit im Untergrund durch Labor- und Feldversuche und anhand theoretischer Modelle

    NASA Astrophysics Data System (ADS)

    Menberg, Kathrin; Steger, Hagen; Zorn, Roman; Reuß, Manfred; Pröll, Markus; Bayer, Peter; Blum, Philipp

    2013-06-01

    For the planning and design of borehole heat exchangers systems, the knowledge of the thermophysical ground parameters is essential. In this study, several methods for the determination of thermal conductivity were used on a borehole for a ground source heat pump system. Thermal conductivity was measured on core samples using laboratory tests and likewise a Thermal Response Test (TRT) was carried out. In addition, several ground parameters, such as water content and carbonate content, were determined by laboratory tests. With these parameters the thermal conductivity was then calculated using different theoretical models. The best agreement between measured and calculated values for thermal conductivities was obtained using the geometric mean. The mean error of these calculations in this study is about 12 %. Thus, the accuracy of the calculation of thermal conductivity is lower than the accuracy of the laboratory tests or TRTs, but it nevertheless represents a simple and more accurate method than parameter estimations based on published values.

  19. Modernisierung durch Feminisierung? Zur Geschichte des Lehrerinnenberufes (Modernization through Feminization -- On the History of the Profession of Women Teachers).

    ERIC Educational Resources Information Center

    Jacobi, Juliane

    1997-01-01

    Argues that the large contribution of women to the history of reform pedagogics substantiates the thesis that the professional image of the teacher is largely determined by the feminization of the profession. Contrasts this approach with other recent theses on the professionalization of male and female teachers. (DSK)

  20. Entwicklung neuer Uebungsformen durch die Einbeziehung des Mediums Fernsehen (Development of New Types of Exercises through the Use of Television)

    ERIC Educational Resources Information Center

    Eggers, Dietrich

    1975-01-01

    Discusses the use of television in university-preparatory schools. The exercises are supplementary to "Deutsch 2000" (M. Hueber, Munich), and deal with land and culture. Three short films are presented, for use in free comment. Examples of grammar, vocabulary and dictation exercises are given. (Text is in German.) (IFS/WGA)

  1. Auf gute Nachbarschaft!. Verantwortungsübernahme durch Unternehmen für die Stadtteilentwicklung - Haniel und Grillo in Duisburg

    NASA Astrophysics Data System (ADS)

    Kleine-König, Christiane; Hohn, Uta

    2016-03-01

    Companies' community involvement turns out to be spatially relevant and-in many cases-to be focused on the near surroundings of the place of business. Some companies strategically align their involvement in order to systematically address local challenges. The essay at hand addresses the subject of corporate social responsibility from a local development perspective. Using the example of two family-owned enterprises based in Duisburg, Haniel and Grillo, it illustrates how socially committed companies can get involved with their local community by acting as good neighbours. Furthermore, it argues that socially committed companies can function as producers of space concerning matters of urban and local development. The specific local settings as well as the economic conditions of the local community serve as an explanatory background of the companies' involvement. The cases presented in this paper prove the firms' specific knowledge of local development needs and possibilities. This makes them qualified partners for local government actors and civil society actors. Thus, in the future, it is worth addressing corporate local responsibility from a governance point of view both in theory and in practice.

  2. Vermittlung sprachlicher Register durch szenisches Spiel nach Dramentexten von Bertolt Brecht (Using Scenes from Bertolt Brecht's Dramas to Further Acquisition of Language Skills)

    ERIC Educational Resources Information Center

    Lemke, Gerhard

    1975-01-01

    Describes the use of some modern German drama in 3rd-year foreign language classes. Following classwork and homework, the students improvised scenes. The handling of certain passages is discussed, including their use in intensive training in speaking. (Text is in German.) (IFS/WGA)

  3. Decomposing the Excited State Dynamics of Carotenoids in Light Harvesting Complexes and Dissecting Pulse Structures from Optimal Control Experiments

    NASA Astrophysics Data System (ADS)

    Papagiannakis, Emmanouil; van Stokkum, Ivo H. M.; van Grondelle, Rienk; Vengris, Mikas; Valkunas, Leonas; Cogdell, Richard J.; Larsen, Delmar S.

    Dispersed transient absorption and multi-pump spectroscopies were used to illustrate how the interplay between excited-state dynamics, saturation, and annihilation phenomena in the LH2 protein from Rhodopseudomonas acidophila generates structured pulses in optimal control experiments.

  4. Biofilm Formation by a Metabolically Versatile Bacterium

    DTIC Science & Technology

    2005-10-02

    biofuel. The goal of this project is to conduct basic studies that will facilitate the development of a process wherein Rhodopseudomonas cells grown on...December, 2004 International Workshop on Biorefinery , Kyoto, Japan, February, 2005 Biotechnology Workshop, Army Resrach office, Cashiers, North Carolina, May...hydrogen, a biofuel. The goal of this project is to conduct basic studies that will facilitate the development of a process wherein Rhodopseudomonas

  5. The reprint of a chapter of Nicolaus Copernicus' principal book by Heinrich Brucaeus, Rostock 1573 (German Title: Der Nachdruck eines Kapitels des Hauptwerkes von Nicolaus Copernicus durch Heinrich Brucaeus, Rostock 1573)

    NASA Astrophysics Data System (ADS)

    Hamel, Jürgen

    The book "De motu primo libri tres" of the Rostock professor Heinrich Brucaeus (1530-1593), which appeared in 1573, contains an unmodified reprint of a section of Copernicus` principal work, first book, 14th chapter, exercise 3. This reprint, hitherto unnoticed, is of interest for the reception of Copernicus' work. This article reproduces the text and presents some research on Brucaeus, who was Tycho Brahe's teacher in Rostock. His biography and his scientific achievements are outlined.

  6. Lehrerbelastungsforschung -- Erweiterung durch ein handlungpsychologisches Belastungskonzept (Research on Teacher's Ability To Cope with Stress -- A Broadening of the Approach by Including a Psychology of Action-Concept of Stress).

    ERIC Educational Resources Information Center

    Krause, Andreas

    2003-01-01

    Reveals that most research on teacher stress relies on personal accounts. Presents a psychology of action-concept of stress and that has been transferred to teacher's instructional activities. Argues that this psychology of action concept of stress helps develop an understanding of teachers' work and what may lead to psychological stress. (CAJ)

  7. Schulentwicklung durch Ruckmeldung der Lernwirksamkeit an die Einzelschule: Moglichkeiten und Grenzen der Schuleffizienzforschung (School Development through Feedback on the Effectiveness of Learning at the Individual School: Possibilities and Limits of School Effectiveness Research).

    ERIC Educational Resources Information Center

    Arnold, Karl-Heinz

    2002-01-01

    Discusses School Effectiveness Research (SER) as a method of determining the learning effectiveness of individual schools and school systems. Determines that SER data offer valuable information for the advice, supervision, and further education of teachers, but lacks enough empirical evidence to make generalized decisions for individual school…

  8. Einbeziehung des Elternhauses durch Lehrer: Art, Ausmass und Bedingungen der Elternpartizipation aus der Sicht von Gymnasiallehrern (The Inclusion of the Parental Home by Teachers: Mode, Extent, and Conditions of Parental Participation from the Perspective of High School Teachers).

    ERIC Educational Resources Information Center

    Wild, Elke

    2003-01-01

    Examines a survey among high school teachers that focuses on their attitudes, convictions, and assessment of external factors and conditions that effect the goal of parent cooperation in homework supervision. Concludes teachers are open minded. Offers clues to optimizing the cooperation between parents and teachers. (CAJ)

  9. orbis (sphaera), circulus, via, iter, orbita -- on the terminological identification of the essential paradigm change in astronomy by Johannes Kepler. (German Title: orbis (sphaera), circulus, via, iter, orbita} -- zur terminologischen Kennzeichnung des wesentlichsten Paradigmawechsels in der Astronomie durch Johannes Kepler)

    NASA Astrophysics Data System (ADS)

    Krafft, Fritz

    2011-08-01

    The use of modern terminology hinders to understand historical astronomical texts and often misleads the reader. Therefore, this study tries to reconstruct the ideas of the way the planets seem to move against the sphere of fixed stars in a non-teleological manner, that means in the original view and with original terms. The study proceeds historically and explains: (1) Aristotle's system of homocentric spheres being hollow spheres of ether turning equally round the earth in the centre of the world, a number of which makes the apparatus of the movement of a planet which produces its apparently unequal motion. (2) Ptolemy's reductionistic system of geometric circles (eccentric deferents, epicycles etc.), which are indeed great circles on non-concentric hollow spheres, whereupon they turn around equally. The space which they take up in all is surrounded by an inner and an outer concentric spherical surface and makes the sphere of the planet. (3) John's of Sacrobosco transferring of the geometric astronomy to the Latin of Middle Ages and the commentators' precision of the Greek-Latin terms. (4) The tradition of the "Theorica planetarum" which makes this geometry physics by allotting every partial moving to a partial material hollow sphere (with spherical surfaces of different centricity) or full sphere of an epicycle (orbes particulares or partialis), a number of which makes the entire sphere of each planet (orbis totalis or totus). - Copernicus also stood within this tradition, except that his entire spheres differ from the earlier ones in size or thickness (because he eliminated the partly very big synodic epicycles and allocated their effect as a mere parallactic one to the yearly moving of the earth) and in the great intervening spaces between each other (a result of measuring the true distances of the planets on the basis of these parallactic effects). (5) Tycho Brahe's refutation of the unchangingness and unpermeableness and therefore solidity of all etherial spheres, what had been the fundamental condition for creating the indirect ways of the planets in all astronomical systems with partial or entire spheres engaging one another. It was particularly Kepler who recognizes that as a result celestial physics requires a complete change. (6) Kepler's replacement of celestial physics. He did not think any more that the apparent (unequal) way of a planet indirectly results from the combination of several equal movements of etherial partial and entire spheres. His planets move their true and real way caused directly by the joint effect of two corporal forces moving the planets both around the sun and to and from it, which latter makes the planet's speed indeed naturally unequal. For this "real way" he coins in late 1604 the specific term "orbita" (the modern "orbit", the German "Bahn". This term then little by little replaced the former non-specific, general description of the apparent or real way (as "via, iter, ambitus, circulus, circuitus" etc.), and Kepler used it increasingly from its introduction (initially frequently joined to a describing definition of this "way") up to the exclusive use in the fifth book of the "Epitome", after this "orbita" had changed its shape from a perfect eccentric circle to an oval and finally an elliptic form. This way Kepler marks the paradigm change of astronomy caused by himself also terminologically.

  10. Enrichment, isolation and identification of sulfur-oxidizing bacteria from sulfide removing bioreactor.

    PubMed

    Luo, Jianfei; Tian, Guoliang; Lin, Weitie

    2013-07-01

    Sulfur-oxidizing bacteria (SOB) are the main microorganisms that participate in the natural sulfur cycle. To obtain SOB with high sulfur-oxidizing ability under aerobic or anaerobic conditions, aerobic and anaerobic enrichments were carried out. Denaturing gradient gel electrophoresis (DGGE) profiles showed that the microbial community changed according to the thiosulfate utilization during enrichments, and Rhodopseudomonas and Halothiobacillus were the predominant bacteria in anaerobic enrichment and aerobic enrichment, respectively, which mainly contributed to the thiosulfate oxidization in the enrichments. Based on the enriched cultures, six isolates were isolated from the aerobic enrichment and four isolates were obtained from the anaerobic enrichment. Phylogenetic analysis suggested the 16S rRNA gene of isolates belonged to the genus Acinetobacter, Rhodopseudomonas, Pseudomonas, Halothiobacillus, Ochrobactrum, Paracoccus, Thiobacillus, and Alcaligenes, respectively. The tests suggested isolates related to Halothiobacillus and Rhodopseudomonas had the highest thiosulfate oxidizing ability under aerobic or anaerobic conditions, respectively; Paracoccus and Alcaligenes could aerobically and anaerobically oxidize thiosulfate. Based on the DGGE and thiosulfate oxidizing ability analysis, Rhodopseudomonas and Halothiobacillus were found to be the main SOB in the sulfide-removing reactor, and were responsible for the sulfur-oxidizing in the treatment system.

  11. Multiple genome sequences reveal adaptations of a phototrophic bacterium to sediment microenvironments.

    SciTech Connect

    Oda, Yasuhiro; Larimer, Frank W; Chain, Patrick S. G.; Malfatti, Stephanie; Shin, Maria V; Vergez, Lisa; Hauser, Loren John; Land, Miriam L; Braatsch, Stephan; Beatty, Thomas; Pelletier, Dale A; Schaefer, Amy L; Harwood, Caroline S

    2008-11-01

    The bacterial genus Rhodopseudomonas is comprised of photosynthetic bacteria found widely distributed in aquatic sediments. Members of the genus catalyze hydrogen gas production, carbon dioxide sequestration, and biomass turnover. The genome sequence of Rhodopseudomonas palustris CGA009 revealed a surprising richness of metabolic versatility that would seem to explain its ability to live in a heterogeneous environment like sediment. However, there is considerable genotypic diversity among Rhodopseudomonas isolates. Here we report the complete genome sequences of four additional members of the genus isolated from a restricted geographical area. The sequences confirm that the isolates belong to a coherent taxonomic unit, but they also have significant differences. Whole genome alignments show that the circular chromosomes of the isolates consist of a collinear backbone with a moderate number of genomic rearrangements that impact local gene order and orientation. There are 3,319 genes, 70% of the genes in each genome, shared by four or more strains. Between 10% and 18% of the genes in each genome are strain specific. Some of these genes suggest specialized physiological traits, which we verified experimentally, that include expanded light harvesting, oxygen respiration, and nitrogen fixation capabilities, as well as anaerobic fermentation. Strain-specific adaptations include traits that may be useful in bioenergy applications. This work suggests that against a backdrop of metabolic versatility that is a defining characteristic of Rhodopseudomonas, different ecotypes have evolved to take advantage of physical and chemical conditions in sediment microenvironments that are too small for human observation.

  12. "Paraffin wax-overlay of pour plate", a method for the isolation and enumeration of purple non-sulfur bacteria.

    PubMed

    Archana, A; Sasikala, Ch; Ramana, Ch V; Arunasri, K

    2004-12-01

    A modification of pour plate technique with an overlay of wax was used for isolation and enumeration of purple non-sulfur bacteria (PNSB) with equal efficiency as that of agar shake culture. The total count of PNSB ranged from 10(5)-10(8) CFU g dry soil(-1) and belonged to the genera of Rhodobacter, Rhodopseudomonas, Rhodocista and Rubrivivax.

  13. Expression of tfx and sensitivity to the rhizobial peptide antibiotic trifolitoxin in a taxonomically distinct group of alpha-proteobacteria including the animal pathogen Brucella abortus.

    PubMed Central

    Triplett, E W; Breil, B T; Splitter, G A

    1994-01-01

    Three phylogenetically distinct groups within the alpha-proteobacteria which differ in trifolitoxin sensitivity are described. Trifolitoxin sensitivity was found in strains of Agrobacterium, Brucella, Mycoplana, Ochrobactrum, Phyllobacterium, Rhodobacter, Rhodopseudomonas, Rhodospirillum, and Rhizobium. Strains of Agrobacterium, Brucella, Phyllobacterium, Rhizobium, and Rhodospirillum were capable of producing trifolitoxin upon conjugal transfer of tfxABCDEFG. PMID:7527627

  14. On the size of the ptolemaic system of the world - a study based on two figures by Johannes Kepler. (German Title: Über die Gröszlig;e des ptolemäischen Weltsystems - Eine Studie, veranlasst durch zwei Bilder bei Johannes Kepler)

    NASA Astrophysics Data System (ADS)

    Oberschelp, Arnold

    It is well known that the geocentric system according to Ptolemy is almost twice as large as the heliocentric planetary system of Copernicus. There are, however, two pictures, given by Kepler in his «Mysterium Cosmographicum» of 1596 which - at first glance - seem to contradict this. The first picture of the heliocentric system is drawn to scale. The second picture shows a geocentric system, which seems to be too small. The puzzle about the size is solved rather trivially by the fact - which is not mentioned by Kepler and which may be overlooked - that the geocentric picture is not drawn to scale and that the angles do not correspond to the degrees noted at them. In order to get a geocentric picture drawn to scale - taking Kepler's degrees for granted - it is necessary to discuss some details of the ptolemaic system. The result is, however, a geocentric system which is too big. The solution of this new puzzle is not obvious. It turns out that one of Keplers degrees (for Mars) does not correspond to the parameters of Ptolemy. Actually, in his book of 1596, Kepler's topic is not the ptolemaic system nor the copernican distances, but his heliocentric model with the five regular polyhedra. While it is interesting to note all these facts, Kepler's pictures and degrees, for the size of the ptolemaic system, lead to a dead end. Using the parameters from the «Almagest» and the principle of nested spheres from the «Planetary Hypotheses» a distance scale (Tab. 10) for the geocentric system is derived. This distance scale, however, is somewhat different from the well known ptolemaic distance scale (Tab. 1). This puzzle is not resolved, but due to the fact that different sources («Almagest» and «Planetary Hypotheses») of Ptolemy are involved. The distances of Tab. 10 correspond better to the ptolemaic system, since the relative thickness of the spheres is computed from the rather precise parameters (eccentricities and epicycle radii) of the «Almagest». The distances of Tab. I, given in the «Planetary Hypotheses», use values for the relative thicknesses of the spheres which are rounded off. Since the pictures of Kepler, when viewed together, are misleading, two new pictures of the copernican and ptolemaic planetary systems are given drawn to the same scale. A final remark is about the radius of the «tychonic system».

  15. Hermeneutische Kompetenz durch Fallarbeit. Uberlegungen zum Stellenwert kasuistischer Forschung und Lehre an Beispielen antinomischen Handelns in sportspadagogischen Berufsfeldern (Hermeneutic Competence through Case Studies. Considerations on the Relevance of Casuistic Research and Theory Exemplified by Antinomic Acting in the Field of Sports Pedagogics).

    ERIC Educational Resources Information Center

    Schierz, Matthias; Thiele, Jorg

    2002-01-01

    Discusses approaches and open questions of a case-oriented, clinically operating sports pedagogy in the acquisition of ability and reflexive judgment. Evaluates the potential contribution of using case studies to train physical education and youth training instructors. (CAJ)

  16. Der Aufbau mentaler Modelle durch bildliche Darstellungen: Eine experimentalle Studie uber die Bedeutung der Merkmalsdimensionen Elaboriertheit und Strukturierheit im Sachunterricht der Grundschule (The Development of Mental Processes through Graphic Representation with Diverging Degrees of Elaboration and Structurization: An Experimental Study Carried Out in Elementary Science Instruction in Primary School).

    ERIC Educational Resources Information Center

    Martschinke, Sabine

    1996-01-01

    Examines types of graphical representation as to their suitability for knowledge acquisition in primary grades. Uses the concept of mental models to clarify the relationship between external presentation and internal representation of knowledge. Finds that students who learned with highly elaborated and highly structured pictures displayed the…

  17. Optoelektronik Infrarotlicht für die Faseroptik

    NASA Astrophysics Data System (ADS)

    Drach, Volker

    2003-07-01

    Die Eigenschaften der kondensierten Materie sind durch die elektronische Bandstruktur bestimmt. Daher sind sie in Raumladungszonen an Oberflächen abhängig von der Ladungsdichte. Ein Team des Forschungszentrums Karlsruhe machte sich nun diesen Effekt zu Nutze und induzierte in metallischen Nanostrukturen durch eine elektrische Spannung reversible Änderungen der makroskopischen Eigenschaften [1].

  18. Nanophysik Durchstimmbare Dehnung in Platin

    NASA Astrophysics Data System (ADS)

    Weissmüller, Jörg; Kramer, Dominik; Viswanath, Raghavan; Gleiter, Herbert

    2003-07-01

    Die Eigenschaften der kondensierten Materie sind durch die elektronische Bandstruktur bestimmt. Daher sind sie in Raumladungszonen an Oberflächen abhängig von der Ladungsdichte. Ein Team des Forschungszentrums Karlsruhe machte sich nun diesen Effekt zu Nutze und induzierte in metallischen Nanostrukturen durch eine elektrische Spannung reversible Änderungen der makroskopischen Eigenschaften [1].

  19. Automatisierte VHDL-Code-Generierung eines Delta-Sigma Modulators

    NASA Astrophysics Data System (ADS)

    Spilka, R.; Ostermann, T.

    2006-09-01

    Im vorliegenden Beitrag wird eine automatische Generierung des VHDL-Codes eines Delta-Sigma Modulators präsentiert. Die Koeffizientenmultiplikation wird hierbei durch Bit-Serielle-Addition durchgeführt. Mit Hilfe zweier neuer Matlab Funktionen wird der Systementwurf durch die bekannte Delta-Sigma Toolbox von R. Schreier erweitert und direkt synthesefähiger VHDL Code erzeugt.

  20. Physik gestern und heute: Visualisierung mit der Schlierenmethode

    NASA Astrophysics Data System (ADS)

    Heering, Peter

    2006-07-01

    Der Name des österreichischen Forschers Ernst Mach ist heute noch mit der Schallgeschwindigkeit verbunden. Diese Auszeichnung resultiert aus Machs Untersuchungen, wie sich Projektile mit Überschallgeschwindigkeit durch die Luft bewegen. Gerade in jüngster Zeit hat die Anwendung derartiger Methoden durch technische Modifikationen wieder einen Aufschwung erfahren.

  1. Leichte Neucodierung von Selenocystein in der Natur

    PubMed Central

    Mukai, Takahito; Englert, Markus; Tripp, H. James; Miller, Corwin; Ivanova, Natalia N.; Rubin, Edward M.; Kyrpides, Nikos C.

    2016-01-01

    Selenocystein (Sec oder U) wird durch Neuzuordnung des Stopp-Codons UGA durch einen Sec-spezifischen Elongationsfaktor und eine charakteristische RNA-Struktur codiert. Um mögliche Codonvariationen zu finden, analysierten wir 6.4 Billionen Basenpaare metagenomischer Daten sowie 24903 mikrobielle Genome für tRNASec-Spezies. UGA ist erwartungsgemäβ das vorherrschende Codon für Sec, allerdings finden wir auch tRNASec-Spezies, die die Stopp-Codons UAG und UAA erkennen, sowie weitere zehn Sense-Codons. Die Synthese von Selenoproteinen durch UAG in Geodermatophilus und Blastococcus sowie durch das Cys-Codon UGA in Aeromonas salmonicida konnte durch metabolische Markierung mit 75Se oder Massenspektrometrie bestätigt werden. Weitere tRNASec-Spezies mit verschiedenen Anticodons ermöglichten es Escherichia coli, die aktive Form des Selenoproteins Formiatdehydrogenase H zu synthetisieren. Der genetische Code ist damit bedeutend flexibler, als bisher angenommen. PMID:27440945

  2. The orientation of the primary donor in bacterial photosynthesis.

    PubMed

    Frank, H A; Friesner, R; Nairn, J A; Dismukes, G C; Sauer, K

    1979-09-11

    The triplet state EPR spectra of magnetically aligned whole cells of Rhodopseudomonas viridis and Rhodopseudomonas palustris display a marked dependence on the orientation of the static EPR field with respect to the alignment field direction. This observation implies that the primary donor species on which the triplets are localized are ordered within the membranes. We have developed a theoretical model for the system to enable calculation of the orientation of the magnetic axes of the primary donor species with respect to the membranes in which they reside. The triplet state spectra are generated by an ensemble of partially ordered magnetic systems and a computer simulation of the experimental results. The triplet orientation is very similar for the two organisms studied, where one axis lies predominantly in the plane of the membrane and the other two axes have approximately equal projections onto the normal to the membrane.

  3. Biohydrogen production from sugarcane bagasse by integrating dark- and photo-fermentation.

    PubMed

    Rai, Pankaj K; Singh, S P; Asthana, R K; Singh, Shweta

    2014-01-01

    Hydrogen production from sugarcane bagasse (SCB) by integrating dark-fermentation by Enterobacter aerogenes MTCC 2822 and photo-fermentation by Rhodopseudomonas BHU 01 was investigated. The SCB was hydrolysed by sulphuric acid and the hydrolysate detoxified by passing through adsorbent resin column (Amberlite XAD-4) to remove the inhibitory furfural, and subjected to dark-fermentation. The cellulosic residue from acid hydrolysis was hydrolysed by the new isolate Cellulomonas fimi to release sugars for H2 production by E. aerogenes, through simultaneous saccharification, filtration and fermentation (SSFF). Cumulative H2 production during dark-fermentation and SSFF was 1000 and 613 ml/L, respectively. The spent media of dark-fermentation and SSFF were utilized for photo-fermentation by Rhodopseudomonas BHU 01. The cumulative H2 production was 755 ml/L for dark-fermentation and 351 ml/L for SSFF spent medium. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Anaerobic degradation of halogenated benzoic acids by photoheterotrophic bacteria.

    PubMed

    van der Woude, B J; de Boer, M; van der Put, N M; van der Geld, F M; Prins, R A; Gottschal, J C

    1994-06-01

    From light-exposed enrichment cultures containing benzoate and a mixture of chlorobenzoates, a pure culture was obtained able to grow with 3-chlorobenzoate (3-CBA) or 3-bromobenzoate (3-BrBA) as the sole growth substrate anaerobically in the light. The thus isolated organism is a photoheterotroph, designated isolate DCP3. It is preliminarily identified as a Rhodopseudomonas palustris strain. It differs from Rhodopseudomonas palustris WS17, the only other known photoheterotroph capable of using 3-CBA for growth, in its independence of benzoate for growth with 3-CBA and in its wider substrate range: if grown on 3-CBA, it can also use 2-CBA, 4-CBA or 3,5-CBA.

  5. Biochemistry and control of the reductive tricarboxylic acid pathway of CO2 fixation and physiological role of the Rubis CO-like protein

    SciTech Connect

    Tabita, F. Robert

    2008-12-04

    During the past years of this project we have made progress relative to the two major goals of the proposal: (1) to study the biochemistry and regulation of the reductive TCA cycle of CO2 fixation and (2) to probe the physiological role of a RubisCO-like protein (RLP). Both studies primarily employ the green sulfur bacterium Chlorobium tepidum as well as other photosynthetic bacteria including Rhodospirillum rubrum and Rhodopseudomonas palustris.

  6. Influence of pH, O/sub 2/, and temperature on the absorption properties of the secondary light-harvesting antenna in members of the family Rhodospirillaceae

    SciTech Connect

    Uffen, R.L.

    1985-09-01

    Results show that holochrome B800-860 (LH II) exhibits unstable light absorption properties in whole cells. This was observed in Rhodopseudomonas capsulata grown anaerobically in light in weakly buffered carbohydrate medium. The whole cell spectrophotometric changes were attributed to mild acid conditions generated during sugar metabolism. LH II absorbency was also destroyed in both R. capsulata and Rhodopseudomonas gelatinosa when cultures growing at neutral pH were acidified to a pH value around 5.0. In contrast, during the same time period of exposure to pH 5.0, only a 50% decrease in Rhodopseudomonas sphaeroides LH II B800 absorbency was measured. At neutral pH, LH II absorbency in suspensions of nongrowing Rhodopseudomonas spp. was also sensitive to O/sub 2/ exposure and to incubation at 30 to 40/sup 0/C. During treatment with O/sub 2/, the rate of LH II B800 absorption decrease in R. gelatinosa and R. sphaeroides was 60 and 40% per h, respectively, compared with their absorbency maximum around 860 nm. Both 860-nm absorbency and the total bacteriochlorophyll content of the cells remained unchanged. On the other hand, no significant decrease in B800 of LH II in R. capsulata occurred during O/sub 2/ exposure, but a 20% absorption decay rate per h of B800 was observed in cells incubated anaerobically at 40/sup 0/C. The near-infrared absorption spectrum of Rhodospirillum rubrum, which does not form LH II, was not significantly influenced by these different pH, aerobic, or temperature conditions.

  7. Temperature Dependence of the Rate Constants of Charge Recombination Reactions in Bacterial Reaction Centers

    NASA Astrophysics Data System (ADS)

    Thuy, T. T.; Yen, V. T. H.; Thao, T. T.; Viet, Nguyen Ai

    The bacterial reaction center couples light-induced electron transfer via a tightly bound ubiquinone (QA) to a mobile ubiquinone (QB). Based on the electron transfer theory by Marcus, we have investigated the rate of charge recombination reactions from Rhodopseudomonas viridis and Rhodobacter sphaeroides, by mean of finding an approximation formula. The results obtained are verified for not only at high and low temperature as the previous works but also at the medium temperature range.

  8. Integrating large-scale functional genomics data to dissect metabolic networks for hydrogen production

    SciTech Connect

    Harwood, Caroline S

    2012-12-17

    The goal of this project is to identify gene networks that are critical for efficient biohydrogen production by leveraging variation in gene content and gene expression in independently isolated Rhodopseudomonas palustris strains. Coexpression methods were applied to large data sets that we have collected to define probabilistic causal gene networks. To our knowledge this a first systems level approach that takes advantage of strain-to strain variability to computationally define networks critical for a particular bacterial phenotypic trait.

  9. Production of lipases by four anoxygenic purple non-sulphur phototrophic bacteria.

    PubMed

    Munjam, Srinivas; Girisham, S; Reddy, S M

    Production of lipases by Rhodopseudomonas palustris, Rhodobacter sphaeroides, Rhodocyclus gelatinosus and Rhodocyclus tenuis in different synthetic media was investigated. Rc. gelatinosus followed by Rb. sphaeroides were good producers of lipases, while Rps. palustris and Rc. tenuis were poor in lipase secretion. Lipase secretion by Rc. gelatinosus was adaptive in nature, while other three bacterial behavior was inconsistent. No positive correlation could be observed between growth and lipase production.

  10. Biofilm Formation by a Metabolically Versatile Bacterium

    DTIC Science & Technology

    2009-03-19

    carbon compound, p - coumarate is used by R. palustris to synthesize a novel chemical language of cell-to–cell communication in the form p -coumaryl...Samatova, D. A. Pelletier, C. S. Harwood, and R.L. Hettich. 2008. Characterization of anaerobic catabolism of p - coumarate in Rhodopseudomonas palustris...found that the plant-derived carbon compound, p - coumarate is used by R. palustris to synthesize a novel chemical language of cell-to–cell

  11. Einsatz einer Echtzeit-Publish/Subscribe-Kommunikation für die Teleoperation mobiler Roboter

    NASA Astrophysics Data System (ADS)

    Lindhorst, Timo; Herms, André; Schulze, Michael

    In der Telerobotik werden mobile Roboter über ein Kommunikationsnetz durch einen Operator ferngesteuert. Um interaktiv zu operieren, mussen Daten in beide Richtungen in Echtzeit kommuniziert werden. Zusätzlich ist eine hohe Ausfallsicherheit des Systems zu gewährleisten. Diese Arbeit beschreibt die Umsetzung ernes solchen Szenarios unter Verwendung einer Echtzeit-Publish/Subscribe-Kommunikation. Ein drahtloses Mesh-Netzwerk erfüllt durch redundante Verbindungen die Anforderungen an die Kommunikation. Eine Publish/Subscribe-Middleware ermöglicht eine inhaltsbasierte Kommunikation und erlaubt dadurch eine hohe Flexibilität der Teilnehmer. Durch die modulare Software-Architektur der Applikationen entsteht ein verteiltes System, in dem mobile Roboter durch netzwerktransparente Kommunikation gesteuert werden.

  12. Kommunikation

    NASA Astrophysics Data System (ADS)

    Raulf, Hans-Ulrich

    Nicht erst seit der Entwicklung des SHELL-Modells durch Hawkins (1987) wird akzeptiert, dass die Leistung einer Cockpit-Crew von den zwischenmenschlichen Beziehungen der einzelnen Crewmitglieder abhängig ist.

  13. Bestrahlungsinduziertes kriechen und schwellen des austenitischen werkstoffes NR. 1.4981 zwischen 400 und 500°C (RIPCEX I)

    NASA Astrophysics Data System (ADS)

    Herschbach, K.; Schneider, W.; Ehrlich, K.

    1981-10-01

    ZusammenfassungFür den Werkstoff Nr. 1.4981 wurde das bestrahlungsinduzierte Volumenschwellen und Kriechen im Temperaturbereich 400 bis 500°C bis zu einer Dosis von max. 63 dpa mittels nichtzerstörender und zerstörender Nachuntersuchungen bestimmt. Dabei zeigte sich eine deutliche Beeinflussung des Volumenschwellens durch eine angelegte Spannung. Das bestrahlungsinduzierte Kriechen wird für den Stahl Nr. 1.4981 durch mindestens zwei Prozesse hervorgerufen, einmal durch den sog. SIPA-Prozess, der auf bevorzugter Absorption von Zwischengitteratomen beruht, zum anderen durch das sog. I-Creep, einem Prozess, der erst nach Einsetzen des Volumenschwellens zum Tragen kommen kann. Für höhere Dosen liefert letzterer Vorgang den dominierenden Beitrag zum Kriechen.

  14. JPRS Report Environmental Issues

    DTIC Science & Technology

    2007-11-02

    Automobile Manufacturers Control Pollution From Paint [H. Schaller; FRANKFURTER ZEITUNG/BLICK DURCH DIE WIRTSCHAFT 19 Jun] 75 Institute Reports on...Force Base in Ogden, Utah, in converting from a chemical to a mechanical method for removing old paint from the aircraft and ground equipment, has...6809-217 Automobile Manufacturers Control Pollution From Paint 90WN0161A Frankfurt/Main FRANKFURTER ZEITUNG/BLICK DURCH DIE WIRTSCHAFT in German

  15. Biotoxine und herstellungsbedingte Kontaminanten

    NASA Astrophysics Data System (ADS)

    Klaffke, Horst St.

    Kontaminanten sind in Lebensmitteln grundsätzlich unerwünscht; in vielen Fällen jedoch nicht völlig zu vermeiden. Viele dieser gesundheitlich bedenklichen Stoffe werden nicht als Rückstände durch die herstellende Industrie in Lebensmittel eingebracht, sondern gelangen aus natürlichen Quellen als Biotoxine in das Lebensmittel oder werden bei Zubereitung z. B. durch Erhitzen im Lebensmittel gebildet.

  16. Rahmen, Herausforderungen und Visionen für die Unternehmensorganisation

    NASA Astrophysics Data System (ADS)

    Westkämper, Engelbert; Seidel, Bernhard; Bruhn, Manfred; Bahke, Torsten; Klotz, Ulrich; Buck, Hartmut

    Die Produktion trägt entscheidend zur gesamten Wertschöpfung des Landes mit mehr als einem Drittel aller Beschäftigten bei. Die direkte Wertschöpfung ist dabei für ein rohstoff- und energiearmes Land allein durch Veredelung und technisches Know-how sowie durch die Herstellung von Produkten für den Binnen- und Weltmarkt möglich.

  17. Method of Moments Analysis of Scattering by Chiral Media

    DTIC Science & Technology

    1991-07-01

    pp. 270- 284, 1922. [38] K. F. Lindman , " Uber eine durch ein isotropes System von spiralf6rmigen Resonatoren erzeugte Rotationspolarisation der...the earliest experimental work on this topic was done in 1920 and 1922 by Lindman [37, 38], who measured the rotation of microwaves propagating through...1990. [37] K. F. Lindman , " Uber die durch ein aktives Raumgitter erzeugte Rotationspo- larisation der elektromagnetischem Wellen," Ann. d. Phys., vol. 69

  18. FAUST: Entwicklung von Fahrerassistenz- und autonomen Systemen

    NASA Astrophysics Data System (ADS)

    Pareigis, Stephan; Schwarz, Bernd; Korf, Franz

    Der Beitrag beschreibt ein Ausbildungs- und Entwicklungsprojekt am Department Informatik der Hochschule für Angewandte Wissenschaften (HAW) Hamburg. Auf verschiedenen Fahrzeugplattformen werden Fahrerassistenz- und autonome Systeme entwickelt. Die zu erarbeitenden Inhalte umfassen die Themen verteilte Echtzeitsysteme, Sensordatenverarbeitung und Bildverarbeitung. Aus didaktischer Sicht wird durch die geforderte Teamarbeit ein hohes Motivationspotential der Studierenden erreicht, durch das neben den technologischen Kenntnissen auch Softskills vermittelt werden.

  19. Analyse der Störfestigkeit nichtlinearer Schaltungen gegenüber leitungsgebundenen elektromagnetischen Störungen mit multi-input Wiener/Hammerstein-Modellen

    NASA Astrophysics Data System (ADS)

    Stegemann, S.; John, W.; Mathis, W.

    2012-09-01

    In dieser Arbeit wird der Einfluss von leitungsgebundenen Störungen untersucht, welche in einen beliebigen Eingang (Signaleingang, Spannungsversorgung, Masse-Potenzial, etc.) einer Analogschaltung einkoppeln. Die zu untersuchende Schaltung wird dazu durch einen Wiener/Hammerstein-Ansatz als nichtlineares System mit zwei Eingängen modelliert. Mit Hilfe dieses Blockmodells werden analytische Ausdrücke derjenigen Frequenzanteile bestimmt, die durch Intermodulationen zwischen Stör- und Eingangssignal am Ausgang einer Schaltung entstehen.

  20. Influence of pH, O2, and temperature on the absorption properties of the secondary light-harvesting antenna in members of the family Rhodospirillaceae.

    PubMed Central

    Uffen, R L

    1985-01-01

    In some Rhodospirillaceae, the primary light-harvesting (LH I) antenna absorbs near-infrared light around 870 nm, whereas LH II (holochrome B800-860) has a major absorption band between 850 and 860 nm (B860) and a minor absorbancy around 800 nm (B800). Results show that, unlike LH I, holochrome B800-860 (LH II) exhibits unstable light absorption properties in whole cells. This was observed in Rhodopseudomonas capsulata grown anaerobically in light in weakly buffered carbohydrate medium; cultures lost both carotenoid-dependent brown-yellow pigmentation and LH II absorbancy. The whole cell spectrophotometric changes were attributed to mild acid conditions generated during sugar metabolism. LH II absorbancy was also destroyed in both R. capsulata and Rhodopseudomonas gelatinosa when cultures growing at neutral pH were acidified to a pH value around 5.0 with HCl. In contrast, during the same time period of exposure to pH 5.0, only a 50% decrease in Rhodopseudomonas sphaeroides LH II B800 absorbancy was measured. At neutral pH, LH II absorbancy in suspensions of nongrowing Rhodopseudomonas spp. was also sensitive to O2 exposure and to incubation at 30 to 40 degrees C. During treatment with O2, the rate of LH II B800 absorption decrease in R. gelatinosa and R. sphaeroides was 60 and 40% per h, respectively, compared with their absorbancy maximum around 860 nm. Both 860-nm absorbancy and the total bacteriochlorophyll content of the cells remained unchanged. On the other hand, no significant decrease in B800 if LH II in R. capsulata occurred during O2 exposure, but a 20% absorption decay rate per h of B800 was observed in cells incubated anaerobically at 40 degrees C. These B800 LH II spectral changes Rhodopseudomonas spp. were prevented by maintaining cells at neutral pH and at 10 degrees C. The near-infrared absorption spectrum of Rhodospirillum rubrum, which does not form LH II, was not significantly influenced by these different pH, aerobic, or temperature conditions

  1. Influence of pH, O2, and temperature on the absorption properties of the secondary light-harvesting antenna in members of the family Rhodospirillaceae.

    PubMed

    Uffen, R L

    1985-09-01

    In some Rhodospirillaceae, the primary light-harvesting (LH I) antenna absorbs near-infrared light around 870 nm, whereas LH II (holochrome B800-860) has a major absorption band between 850 and 860 nm (B860) and a minor absorbancy around 800 nm (B800). Results show that, unlike LH I, holochrome B800-860 (LH II) exhibits unstable light absorption properties in whole cells. This was observed in Rhodopseudomonas capsulata grown anaerobically in light in weakly buffered carbohydrate medium; cultures lost both carotenoid-dependent brown-yellow pigmentation and LH II absorbancy. The whole cell spectrophotometric changes were attributed to mild acid conditions generated during sugar metabolism. LH II absorbancy was also destroyed in both R. capsulata and Rhodopseudomonas gelatinosa when cultures growing at neutral pH were acidified to a pH value around 5.0 with HCl. In contrast, during the same time period of exposure to pH 5.0, only a 50% decrease in Rhodopseudomonas sphaeroides LH II B800 absorbancy was measured. At neutral pH, LH II absorbancy in suspensions of nongrowing Rhodopseudomonas spp. was also sensitive to O2 exposure and to incubation at 30 to 40 degrees C. During treatment with O2, the rate of LH II B800 absorption decrease in R. gelatinosa and R. sphaeroides was 60 and 40% per h, respectively, compared with their absorbancy maximum around 860 nm. Both 860-nm absorbancy and the total bacteriochlorophyll content of the cells remained unchanged. On the other hand, no significant decrease in B800 if LH II in R. capsulata occurred during O2 exposure, but a 20% absorption decay rate per h of B800 was observed in cells incubated anaerobically at 40 degrees C. These B800 LH II spectral changes Rhodopseudomonas spp. were prevented by maintaining cells at neutral pH and at 10 degrees C. The near-infrared absorption spectrum of Rhodospirillum rubrum, which does not form LH II, was not significantly influenced by these different pH, aerobic, or temperature conditions.

  2. Geothermie

    NASA Astrophysics Data System (ADS)

    Zahoransky, Richard; Allelein, Hans-Josef; Bollin, Elmar; Oehler, Helmut; Schelling, Udo

    Mit zunehmender Tiefe nimmt die Erdtemperatur zu. Im flüssigen inneren Erdkern herrschen Temperaturen von 3000 bis 6000 K. Durch Wärmeleitung entsteht ein Wärmestrom zur kalten Erdoberfläche. Nur an wenigen Stellen in der oberen Erdkruste wird Erdwärme durch Wasserund Dampfströmungen an die Oberfläche befördert. Die vom Erdkern abgegebene Wärme wird zu etwa 60 % durch den im Kern ablaufenden radioaktiven Zerfall, im Wesentlichen der Elemente Kalium K-40, Thorium Th-232, Uran U-235 und U-238, gespeist. Der Rest der Wärme zählt zur Ursprungswärme, die einmal bei der Erdentstehung entstand und zum anderen durch umgewandelte kinetische Energie großer Meteoriteneinschläge sowie permanent durch die Erstarrung des Erdkernmaterials in der Übergangszone vom flüssigen zum festen Kern freigesetzt wird. Die Erstarrung setzt Kristallisationswärme (Latentwärme) frei. Die Geothermie ist für menschliche Zeitvorstellungen unerschöpflich, obwohl sich langfristig die Erde abkühlt.

  3. Die einzelnen Beanspruchungsarten

    NASA Astrophysics Data System (ADS)

    Böge, Gert; Böge, Wolfgang

    Wird ein Stab mit beliebigem, gleichbleibendem Querschnitt durch die äußere Kraft F in der Schwerachse auf Zug oder Druck beansprucht, so wird bei gleichmäßiger Spannungsverteilung, also in genügender Entfernung vom Angriffspunkt der Kraft, die Zug- oder Druckspannung σ_{z,d}= Zug- oder Druckkraft F/Querschnittsfläche A {Zug- und Druck-Hauptgleichung} σ_{z,d}=F/A\\qquad σ&F&A N/mm2 & N&mm2 Je nach vorliegender Aufgabe kann die Hauptgleichung umgestellt werden zur Berechnung des erforderlichen Querschnitts (Querschnittsnachweis): A_{erf}=F/σ_{zul} Berechnung der vorhandenen Spannung (Spannungsnachweis): σ_{vorh}=F/A Berechnung der maximal zulässigen Belastung (Belastungsnachweis): F_{max}=σ_{zul}A Treten Zug- und Druckspannungen in einer Rechnung gleichzeitig auf, werden sie durch den Index z und d oder durch das Vorzeichen + und - unterschieden.

  4. Grundlagen

    NASA Astrophysics Data System (ADS)

    Weinzierl, Stefan

    Jede Form der auditiven Kommunikation durchläuft eine Übertragungskette. Im einfachsten Fall besteht sie aus einer Schallquelle, der Luft als akustischem Medium und einem Hörer. Bereits hier beeinflussen die Eigenschaften der Quelle, des Mediums, des umgebenden Raums und des Empfängers das Verständnis der übermittelten Nachricht auf charakteristische Weise. Jeder Musiker und jeder Schauspieler kann bestätigen, wie stark seine "Botschaft“ etwa von den Eigenschaften des Aufführungsraums beeinflusst wird. Selbst in dieser Alltagssituation wird die Kommunikation also durch ein Audiosystem vermittelt und durch dessen Eigenschaften spezifisch geprägt, erst recht natürlich bei der Übertragung durch technische, elektronische Medien.

  5. Single-protein study of photoresistance of pigment-protein complex in lipid bilayer

    NASA Astrophysics Data System (ADS)

    Uchiyama, Daisuke; Hoshino, Hajime; Otomo, Kohei; Kato, Taro; Onda, Ken-ichi; Watanabe, Akira; Oikawa, Hiroyuki; Fujiyoshi, Satoru; Matsushita, Michio; Nango, Mamoru; Watanabe, Natsuko; Sumino, Ayumi; Dewa, Takehisa

    2011-07-01

    Photoresistance of a pigment-binding membrane protein, light-harvesting 2 (LH2) complex from the photosynthetic bacterium, Rhodopseudomonas acidophila, was investigated by fluorescence of single LH2 complexes at a temperature of 296 K. Before irreversibly stopping fluorescence, a single LH2 complex in phospholipid bilayer of dimyristoylphosphatidylcholine (DMPC) emitted on average 4 times more fluorescence photons than a complex in detergent micelle of octylglucopyranoside (OG). Fluorescence-excitation spectrum of single LH2 complexes taken at 5 K showed that the LH2 complex is structurally less perturbed in DMPC bilayer than in OG micelle, suggesting that structural instability reduces photoresistance of LH2.

  6. Self-assembled monolayer of light-harvesting core complexes of photosynthetic bacteria on an amino-terminated ITO electrode

    PubMed Central

    Suemori, Yoshiharu; Nagata, Morio; Nakamura, Yukari; Nakagawa, Katsunori; Okuda, Ayumi; Inagaki, Jun-ichi; Shinohara, Kiyoshi; Ogawa, Makiko; Iida, Kouji; Dewa, Takehisa; Yamashita, Keiji; Gardiner, Alastair; Cogdell, Richard J.

    2006-01-01

    Light-harvesting antenna core (LH1-RC) complexes isolated from Rhodospirillum rubrum and Rhodopseudomonas palustris were successfully self-assembled on an ITO electrode modified with 3-aminopropyltriethoxysilane. Near infra-red (NIR) absorption, fluorescence, and IR spectra of these LH1-RC complexes indicated that these LH1-RC complexes on the electrode were stable on the electrode. An efficient energy transfer and photocurrent responses of these LH1-RC complexes on the electrode were observed upon illumination of the LH1 complex at 880 nm. PMID:17111238

  7. Fluorescence enhancement of light-harvesting complex 2 from purple bacteria coupled to spherical gold nanoparticles

    SciTech Connect

    Bujak, Ł.; Czechowski, N.; Piatkowski, D.; Litvin, R.; Mackowski, S.; Brotosudarmo, T. H. P.; Pichler, S.; Cogdell, R. J.; Heiss, W.

    2011-10-24

    The influence of plasmon excitations in spherical gold nanoparticles on the optical properties of a light-harvesting complex 2 (LH2) from the purple bacteria Rhodopseudomonas palustris has been studied. Systematic analysis is facilitated by controlling the thickness of a silica layer between Au nanoparticles and LH2 complexes. Fluorescence of LH2 complexes features substantial increase when these complexes are separated by 12 nm from the gold nanoparticles. At shorter distances, non-radiative quenching leads to a decrease of fluorescence emission. The enhancement of fluorescence originates predominantly from an increase of absorption of pigments comprising the LH2 complex.

  8. Nucleotide sequence of the Rhodospirillum rubrum atp operon.

    PubMed Central

    Falk, G; Hampe, A; Walker, J E

    1985-01-01

    The nucleotide sequence was determined of a 8775-base-pair region of DNA cloned from the photosynthetic non-sulphur bacterium Rhodospirillum rubrum. It contains a cluster of five genes encoding F1-ATPase subunits. The genes are arranged in the same order as F1 genes in the Escherichia coli unc operon. However, as in the related organism Rhodopseudomonas blastica, neither genes for components of F0, the membrane sector of ATP synthase, nor a homologue of the E. coli uncI gene are associated with this locus, as they are in E. coli. Images Fig. 2. PMID:2861810

  9. Terminal steps of bacteriochlorophyll a phytol formation in purple photosynthetic bacteria.

    PubMed Central

    Shioi, Y; Sasa, T

    1984-01-01

    Four chemically different bacteriochlorophylls (Bchls) a esterified with geranylgeraniol, dihydrogeranylgeraniol, tetrahydrogeranylgeraniol, and phytol have been detected by high-pressure liquid chromatography in cell extracts from Rhodopseudomonas sphaeroides and Chromatium vinosum. Bchl a containing phytol is the principal component, and the other three Bchls a comprise about 4% of the total Bchls a in stationary-phase cells of R. sphaeroides and C. vinosum. The high levels of the minor pigments occur in the beginning of Bchl a phytol formation, indicating that they are not degradation products, but intermediates of Bchl a phytol formation. PMID:6609153

  10. A Fluorescent, Reagentless Biosensor for ATP, Based on Malonyl-Coenzyme A Synthetase

    PubMed Central

    2015-01-01

    A fluorescent reagentless biosensor for ATP has been developed, based on malonyl-coenzyme A synthetase from Rhodopseudomonas palustris as the protein scaffold and recognition element. Two 5-iodoacetamidotetramethylrhodamines were covalently bound to this protein to provide the readout. This adduct couples ATP binding to a 3.7-fold increase in fluorescence intensity with excitation at 553 nm and emission at 575 nm. It measures ATP concentrations with micromolar sensitivity and is highly selective for ATP relative to ADP. Its ability to monitor enzymatic ATP production or depletion was demonstrated in steady-state kinetic assays in which ATP is a product or substrate, respectively. PMID:26355992

  11. Inelastic neutron scattering study of light-induced dynamics of a photosynthetic membrane system

    SciTech Connect

    Furrer, A.; Stoeckli, A.

    2010-01-15

    Inelastic neutron scattering was employed to study photoeffects on the molecular dynamics of membranes of the photosynthetic bacterium Rhodopseudomonas viridis. The main photoactive parts of this biomolecular system are the chlorophyll molecules whose dynamics were found to be affected under illumination by visible light in a twofold manner. First, vibrational modes are excited at energies of 12(2) and 88(21) cm{sup -1}. Second, a partial 'freezing' of rotational modes is observed at energies of 1.2(3) and 2.9(5) cm{sup -1}. These results are attributed to a possible coupling between molecular motions and particular mechanisms in the photosynthetic process.

  12. Photoelectric currents across planar bilayer membranes containing bacterial reaction centers. Response under conditions of single electron turnover.

    PubMed Central

    Packham, N K; Dutton, P L; Mueller, P

    1982-01-01

    Light-induced electric current and potential responses have been measured across planar phospholipid membranes containing reaction centers from the photosynthetic bacterium Rhodopseudomonas sphaeroides. Under conditions in which the reaction centers are restricted to a single electron turnover, the responses can be correlated with the light-induced electron transfer reactions associated with the reaction center. The results indicate that electron transfer from the bacteriochlorophyll dimer to the primary ubiquinone molecule, and from ferrocytochrome c to the oxidized dimer occur in series across the planar membrane. Electron transfer from the primary to secondary ubiquinone molecule is not electrogenic. PMID:6277403

  13. Functional reconstitution of photosynthetic reaction centers in planar lipid bilayers

    PubMed Central

    Schönfeld, M.; Montal, M.; Feher, G.

    1979-01-01

    Planar lipid bilayers containing reaction centers from Rhodopseudomonas sphaeroides R-26 were formed by apposing two reaction center—lipid monolayers formed from a reaction center—lipid complex in hexane. Secondary donors (cytochrome c) and acceptors (ubiquinone-0) were added on opposite sides of the membrane. Upon illumination, this system generated transient and steady-state voltages and currents. The wavelength dependence of the photoresponse matched the absorption spectrum of reaction centers. A simple model based on the transfer of charges across the membrane that explains the salient features of the photoresponse is presented. PMID:16592737

  14. (Anaerobic metabolism of aromatic compounds by phototrophic bacteria: Biochemical aspects)

    SciTech Connect

    Gibson, J.

    1989-01-01

    Two aspects of the work proposed have received major emphasis during the period since the grant was activated: isolation and characterization of transposon insertion mutants of Rhodopseudomonas palusrtis defective in phototrophic growth on aromatic compounds, and attempts to purify and characterize the Coenzyme A ligase enzyme involved in activating 4-hydroxybenzoate. The HPLC apparatus was installed in August, and calibration of columns both for metabolite and for protein separations has been initiated. A start has also been made on synthesis of Coenzyme A thioesters of compounds that are potential intermediates in the anaerobic degradation pathways. 1 tab.

  15. Procedure for rapid isolation of photosynthetic reaction centers using cytochrome c affinity chromatography

    SciTech Connect

    Brudvig, G.W.; Worland, S.T.; Sauer, K.

    1983-02-01

    Horse heart cytochrome c linked to Sepharose 4B is used to purify reaction centers from Rhodopseudomonas sphaeroides R-26. This procedure allows for an initial recovery of 80-90% of the bacterial reaction centers present in chromatophore membranes. High purity reaction centers (A/sub 280//A/sub 802/ < 1.30) can be obtained with a 30% recovery. Reaction centers from wild-type Rps. sphaeroides and Rps. capsulata also bind to a cytochrome c column. Cytochrome c affinity chromatography can also be used to isolate photosystem I complexes from spinach chloroplasts.

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

    SciTech Connect

    Tabita, Fred Robert

    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.

  17. Digitalisierung in der Energiewirtschaft - empirische Untersuchung und Wertschöpfungskette

    NASA Astrophysics Data System (ADS)

    Dell, Timo

    Die Energiewirtschaft nutzt seit je her digitale Strukturen zur Umsetzung ihrer Prozesse. Durch den (neuen) verabschiedeten politischen Ordnungsrahmen - dem Gesetz zur Digitalisierung der Energiewende - und durch die rasante Fortentwicklung technologischer Strukturen ergeben sich jedoch die Wertschöpfungsstufen erweiternde, diversifizierende und innovative Möglichkeiten für Energieversorger (EVU) Geschäftsfelder auszubauen bzw. neue zu erschließen. Dabei ist die digitale (R)Evolution keine rein technische Umsetzung, sondern insbesondere auch eine unternehmensinterne, strategische und intern-kulturelle Herausforderung.

  18. Abgasnachbehandlung

    NASA Astrophysics Data System (ADS)

    Wirth, Ralf; Raatz, Thorsten

    Bisher wurde die Emissionsminderung beim Dieselmotor vorwiegend durch inner motorische Maßnahmen bewirkt. Bei vielen Diesel-Fahrzeugen werden die vom Motor freigesetzten Emissionen (Rohemissionen) jedoch die zukünftig in Europa, den USA und Japan geltenden Emissionsgrenzwerte überschreiten. Die erforderlichen hohen Minderungsraten lassen sich voraussichtlich nur durch eine effiziente Kombination von innermotorischen und nachmotorischen Maßnahmen erreichen. Analog zur bewährten Vorgehensweise bei Benzinfahrzeugen werden deshalb auch für Dieselfahrzeuge verstärkt Systeme zur Abgas - nachbehandlung (nachmotorische Emis sions minderung) entwickelt.

  19. Bewertung von Fahrerassistenzsystemen mittels der Vehicle in the Loop-Simulation

    NASA Astrophysics Data System (ADS)

    Bock, Thomas

    Mit der Vehicle in the Loop-Simulation hat Audi eine Test- und Simulationsumgebung für Fahrerassistenzsysteme entwickelt, welche die Vorzüge eines realen Versuchsfahrzeugs mit der Sicherheit und Reproduzierbarkeit von Fahrsimulatoren kombiniert. Virtueller Fremdverkehr, Straßenbegrenzungen oder sonstige simulierte Gegenstände werden durch ein "Optical see through Head Mounted Display“ während der Fahrt realitätsnah und kontaktanalog für den Fahrer eingeblendet. Besonders bei der Erprobung aktiver Fahrerassistenzsysteme eröffnen sich durch das Konzept des virtuellen Fremdverkehrs im realen Versuchsfahrzeug neue Möglichkeiten.

  20. Local Dynamic Map als modulares Software Framework für Fahrerassistenzsysteme

    NASA Astrophysics Data System (ADS)

    Reisdorf, P.; Auerswald, A.; Wanielik, G.

    2015-11-01

    Moderne Fahrerassistenzsysteme basieren auf der Verarbeitung von Informationen, welche durch die Umfeldwahrnehmung mit unterschiedlicher Sensorik erfolgt. Neben den Informationen aus dem eigenen Fahrzeug ergeben sich durch unterschiedliche Kommunikationsmöglichkeiten (Car2Car, Car2X,...) erweiterte Umfeldwahrnehmungen (siehe Abb. 1). Diese Daten gilt es aufbereitet und zielorientiert einer Anwendung zur Verfügung zu stellen, was mit Hilfe einer Local Dynamic Map (LDM) erfüllt werden kann. Die vorliegende Veröffentlichung beschreibt den Aufbau, Verwendungszweck und Eigenschaften einer entwickelten LDM und geht auf einige Applikationen ein, die mit Hilfe dieser realisiert wurden.

  1. Methodisches Vorgehen zur integralen Auslegung von Produkt und Montage

    NASA Astrophysics Data System (ADS)

    Meyer, André; Grauer, Matthias; Rittner, Martin; Zeltner, Stefan; März, Martin; Egelkraut, Sven; Birkner, Klaus; Braun, Steven

    Die Produktlebenszyklen werden durch den steigenden Wettbewerbsdruck stetig kürzer. Dies veranlasst Unternehmen, Produktinnovationen in immer geringeren Zeitabständen auf den Markt zu bringen und Produktentwicklungszeiten zu verkürzen. Zusätzlich wirken sich erhöhte Anforderungen bezüglich Produktzuverlässigkeit und -lebensdauer erschwerend aus. Um dieser Herausforderung zu begegnen ist eine enge Zusammenarbeit zwischen Entwicklung, Konstruktion, Fertigungsplanung und Prozessentwicklung unabdingbar, denn nur durch eine optimale Abstimmung von Konstruktion und Fertigungsprozess lassen sich die hohen Qualitätsanforderungen erfüllen.

  2. [Production of 5-aminolevulinic acid from organic industrial wastewater by photosynthetic bacteria].

    PubMed

    Xiuyan, Liu; Xiangyang, Xu; Min, Ye; Shuo, Xiang

    2008-09-01

    We used Rhodopseudomonas strains with high-yield of 5-aminolevulinic acid (ALA) to produce ALA from wastewater of producing monosodium glutamate, citric acid, beer, and soybean product. Cultivation was carried out under anaerobic light condition (3000 Lux) at 30 degrees C. For comparison, we tested the addition of levulinic acid (LA), glycin and succinate to the substrate to increase the production of ALA, effect of sterilization of the wastewater for both strains. Cell mass concentration (OD660) and the content of ALA were determined with spectrophotometer. Without adding levulinic acid (LA), glycin and succinate, the growth of strain 99-28 reached plateau after 72-96 h. The maxiam ALA production was obtained at 96 h. Both the yield of ALA and the Chemical Oxygen Demand (CODcr) removal rate of monosodium glutamate waster water were the highest in all tested wasterwaters. When LA, glycin and succinate were added, ALA production of strain 99-28 was significantly increased whereas the CODcr removal was adversely affected. Non-sterial wasterwater slightly reduced the growth and CODcr removal rate of strain 99-28, however the ALA production could be strongly reduced with the addition of LA, glycin and succinate. The growth and CODcr removal of mutant strain L-1 was similar with strain 99-28, but its ALA production was much higher than that of strain 99-28. The Rhodopseudomonas strains screened in our laboratory can use organic wasterwater as substrates to produce ALA and remove CODcr.

  3. Biomass recovery during municipal wastewater treatment using photosynthetic bacteria and prospect of production of single cell protein for feedstuff.

    PubMed

    Saejung, Chewapat; Thammaratana, Thani

    2016-12-01

    Utilization of photosynthetic bacteria (PSB) for wastewater treatment and production of biomass for economical single cell protein production is a feasible option. In this study, Rhodopseudomonas sp. CSK01 was used for municipal wastewater treatment and the effect of initial pH, light intensity and additional carbon source was investigated. Optimum chemical oxygen demand (COD) removal and biomass production were achieved when the initial pH and light intensity were 7 and 4000 lux, respectively. The specific growth rate, biomass yield and biomass productivity were found to be 0.4/d, 3.2 g/g COD and 2.1 g/L/d, respectively, which were improved by 100%, 167% and 200% relative to the original condition. Under the optimal conditions, COD removal reached 85% and maximum biomass was 6.2 g/L accomplished within three days of cultivation. The biomass had a relatively high protein content (60.1%) consisting of all essential amino acids. The contents of histidine, lysine, phenylalanine and leucine were superior to those of the previously described PSB. Results showed that COD removal was not improved in the presence of additional carbon sources (glucose, sucrose and malic acid). The addition of malic acid significantly increased the biomass accumulation by 279% relative to the original condition, whereas COD removal was declined due to carbon catabolite repression. In this study, PSB biomass recovery and catabolite repression are proposed in municipal wastewater treatment by Rhodopseudomonas sp.

  4. Grundlagen des Tissue Engineering

    NASA Astrophysics Data System (ADS)

    Mayer, Jörg; Blum, Janaki; Wintermantel, Erich

    Die Organtransplantation stellt eine verbreitete Therapie dar, um bei krankheitsoder unfallbedingter Schädigung eines Organs die Gesamtheit seiner Funktionen wieder herzustellen, indem es durch ein Spenderorgan ersetzt wird. Organtransplantationen werden für die Leber, die Niere, die Lunge, das Herz oder bei schweren grossflächigen Verbrennungen der Haut vorgenommen. Der grosse apparative, personelle und logistische Aufwand und die Risiken der Transplantationschirurgie (Abstossungsreaktionen) sowie die mangelnde Verfügbarkeit von immunologisch kompatiblen Spenderorganen führen jedoch dazu, dass der Bedarf an Organtransplantaten nur zu einem sehr geringen Teil gedeckt werden kann. Sind Spenderorgane nicht verfügbar, können in einzelnen Fällen lebenswichtige Teilfunktionen, wie beispielsweise die Filtrationsfunktion der Niere durch die Blutreinigung mittels Dialyse ersetzt oder, bei mangelnder Funktion der Bauchspeicheldrüse (Diabetes), durch die Verabreichung von Insulin ein normaler Zustand des Gesamtorganismus auch über Jahre hinweg erhalten werden. Bei der notwendigen lebenslangen Anwendung apparativer oder medikamentöser Therapie können für den Patienten jedoch häufig schwerwiegende, möglicherweise lebensverkürzende Nebenwirkungen entstehen. Daher werden in der Forschung Alternativen gesucht, um die Funktionen des ausgefallenen Organs durch die Implantation von Zellen oder in vitro gezüchteten Geweben möglichst umfassend wieder herzustellen. Dies erfordert biologisch aktive Implantate, welche die für den Stoffwechsel des Organs wichtigen Zellen enthalten und einen organtypischen Stoffwechsel entfalten.

  5. Combined Therapy of Septicemia with Ofloxacin and/or Synthetic Trehalose Dicorynomycolate (S-TDCM) in Irradiated and Wounded Mice (Die Kombinierte Therapie der Septikaemie mit Ofloxacin und/oder Synthetischem Trehalose- Dicorynomycolat (S-TDCM) bei Bestrahlten und Verwundeten Maeusen)

    DTIC Science & Technology

    1989-01-01

    for effective therapy of polymicrobic infections in irradiated/wounded mice. ZUSAMMENFASSUNG Im Gefolge letaler Bestrahlung fallen MAuse normalerweise...durch die Inhalation von Methoxyfluran andsthetisiert wurden. Eine Stunde nach 8.0 G.- Germma- Bestrahlung wurden dorsal Haut- und Muskelgewebe in Ent

  6. Nicolaus Copernicus Gesamtausgabe. Band III/1: Kommentar zu "De revolutionibus".

    NASA Astrophysics Data System (ADS)

    Schmeidler, F.

    Nicolaus Copernicus Gesamtausgabe, H. M. Nobis, M. Folkerts (eds.). Contents: 1. Die Entstehungsgeschichte von "De revolutionibus". 2. Die bisherigen Editionen. 3. Die bisherigen Kommentare. 4. Inhaltliche Kommentierung des Hauptwerks von Copernicus. 5. Anmerkungen zu einzelnen Stellen. 6. Durch wen wurde Copernicus geistig beeinflußt?

  7. Grundlagen der Fahrphysik

    NASA Astrophysics Data System (ADS)

    Kost, Friedrich

    Bewegungsänderungen eines Körpers lassen sich nur durch Kräfte erreichen. Auf ein Fahrzeug wirken im Fahrbetrieb viele Kräfte ein. Eine wichtige Funktion übernehmen dabei die Reifen: jede Bewegungsänderung des Fahrzeugs führt über am Reifen wirkende Kräfte.

  8. Zeitgesteuerte und selbstorganisierende Fahrzeug-zu-Fahrzeug-Kommunikation auf Basis von Ad-hoc-WLAN

    NASA Astrophysics Data System (ADS)

    Munstermann, Marco; Heitmann, Hans Heinrich

    Da das Basisprotokoll (CSMA/CA) des WLAN-Standards nicht in der Lage ist, der geforderten Aufgabenstellung gerecht zu werden, muss ein zuverlässiges, fehlertolerantes, faires und skalierbares Protokoll entwickelt werden. Zudem sollte es sich durch eine hohe Verfügbarkeit, eine bestimmbare Aktualisierungsrate und definierte Latenzzeiten auszeichnen.

  9. Kommunikation in Automatisierungssystemen

    NASA Astrophysics Data System (ADS)

    Wellenreuther, Günter; Zastrow, Dieter

    Die Automatisierungstechnik befindet sich im Umbruch. Durch Anwendung moderner Kommunikationstechnik erhofft man sich entscheidende Verbesserungen bei Effizienz und Flexibilität der Automatisierungsprozesse. Der Begriff der Automatisierungstechnik umfasst heute mehr als nur das Automatisieren im Sinne von Steuern, Regeln und Visualisieren, eingeschlossen ist auch das Kommunizieren.

  10. The East-German Research Landscape in Transition. Part C. Research at East-German Universities

    DTIC Science & Technology

    1993-03-10

    institutes of the NATIONAL RESEARCH CENTERS, of the INSTITUTES OF THE BLUE LIST, of the FRAUNHOFER SOCIETY, the MAX-PLANCK SOCIETY, and the large number...Renaturalisierung durch Kombination von Begrilnung und Sanierung. Biotechnologie der Bodensanierung, Deponiedetoxifikation, Miillkompostierung und...Pharinakaentwicklung, Bioteste, BioprozeBtechnik, Fremdstoffabbau, Altlastensanierung, Abproduktnutzung, Bodensanierung, * Biotechnologie , bkotechnologie, Umwelt

  11. Die Gasultrazentrifuge als mediale Projektion des Kalten Krieges

    NASA Astrophysics Data System (ADS)

    Helmbold, Bernd

    Studien der letzten Dekaden nach der Wiedervereinigung von BRD und DDR erweitern die Perspektive der Wissenschaftsgeschichte vom Fokus des Big Science und der technisch-militärisch-industriellen Auseinandersetzung zwischen den zwei Blöcken zu einer globalen Transformation im Konflikt der Supermächte geprägt durch lokale und auch interne Ausformungen.

  12. Networking as a Seismograph for Social Development. A Contribution to the Function Expansion of Networks Using the Example of Health Promotion of the Socially Disadvantaged (Netzwerkbildung als Seismograph gesellschaftlicher Entwicklungen: Ein Beitrag zur Funktionserweiterung von Netzwerken am Beispiel der Gesundheitsfoerderung von sozial Benachteiligten)

    DTIC Science & Technology

    2008-03-01

    vollzieht sich in den letzten Jahren Ober eine Vielzahl von Netzwerken, uber die sich unterschiedlichste Akteure miteinander verknQ~pft haben. In...indirekt, politische 2 Akteure zu adressieren und bisherige Handlungsdefizite der Gesundheitsf6rderung bei sozial Benachteiligten auch uber neue...klassischen Sinne der Korporatismusanalyse impliziert, sondern gar eine Form der Einwandvorwegnahme darsteilt. Auf der Grundlage der durch die bislang uber

  13. Die Deutsche Statistische Gesellschaft in der Weimarer Republik und während der Nazidiktatur

    NASA Astrophysics Data System (ADS)

    Wilke, Jürgen

    Nach anfänglichen Schwierigkeiten durch den 1. Weltkrieg erlangte die Deutsche Statistische Gesellschaft (DStatG) unter dem renommierten Statistiker und Vorsitzenden der DStatG, Friedrich Zahn, durch eine Vielzahl von Aktivitäten hohes Ansehen. Es gab Bestrebungen, Statistiker aus allen Arbeitsfeldern der Statistik in die DStatG zu integrieren, wobei die "Mathematische Statistik" nur zögerlich akzeptiert wurde (Konjunkturforschung, Zeitreihenanalyse). Nach der Machtübernahme 1933 durch Adolf Hitler geriet die DStatG in das Fahrwasser nationalsozialistischer Ideologie und Politik (Führerprinzip, Gleichschaltung des Vereinswesens). Damit war eine personelle Umstrukturierung in der DStatG verbunden. Politisch Missliebige und rassisch Verfolgte mussten die DStatG verlassen (Bernstein, Freudenberg, Gumbel u.a.). Unter den Statistikern gab es alle Abstufungen im Verhalten zum Regime von Ablehnung und zwangsweiser Anpassung über bereitwilliges Mitläufertum bis zu bewusster Täterschaft. Besonders die Bevölkerungsstatistik wurde durch die NS- Rassenpolitik auf lange Sicht diskreditiert. Im Rahmen von Wirtschaftsplanung und Aufrüstung wurden neue zukunftsträchtige statistische Modelle (Grünig, Bramstedt, Leisse) entwickelt.

  14. Europäisches Organ der Festkörperforschung und DDR-Devisenbringer Die Zeitschrift Physica Status Solidi im Kalten Krieg

    NASA Astrophysics Data System (ADS)

    Hoffmann, Dieter

    Mit dem Ziele, ein einheitliches internationales Organ der Festkörperphysik für den europäischen Raum zu schaffen, das eine rasche Publikation der für das Festkörpergebiet repräsentative Arbeiten ermöglicht, wird durch ein internationales Herausgebergremium eine neue wissenschaftliche Zeitschrift gegründet.

  15. Kunststoffe (Polymere)

    NASA Astrophysics Data System (ADS)

    Weißbach, Wolfgang

    Polymere bestehen aus Riesen- oder Makromolekülen, die durch chemische Reaktionen aus einfachen, niedermolekularen Verbindungen entstehen, den Monomeren. Ausgangsstoffe sind überwiegend Kohlenwasserstoffe (KW), die größte Gruppe der C-Verbindungen. Sie müssen reaktionsfähige Stellen besitzen, das sind OH-Gruppen oder Dopppelbindungen.

  16. TÜV - Zertifizierungen in der Life Science Branche

    NASA Astrophysics Data System (ADS)

    Schaff, Peter; Gerbl-Rieger, Susanne; Kloth, Sabine; Schübel, Christian; Daxenberger, Andreas; Engler, Claus

    Life Sciences [1] (Lebenswissenschaften) sind ein globales Innovationsfeld mit Anwendungen der Bio- und Medizinwissenschaften, der Pharma-, Chemie-, Kosmetik- und Lebensmittelindustrie. Diese Branche zeichnet sich durch eine stark interdisziplinäre Ausrichtung aus, mit Anwendung wissenschaftlicher Erkenntnisse und Einsatz von Ausgangsstoffen aus der modernen Biologie, Chemie und Humanmedizin sowie gezielter marktwirtschaftlich orientierter Arbeit.

  17. CAD in der Praxis

    NASA Astrophysics Data System (ADS)

    Labisch, Susanna

    Konstruktion und Fertigung erfolgen in der Praxis fast ausschließlich rechnerunterstützt. Mit diesem Rechnereinsatz beim Konstruieren (CAD, Computer Aided Design) und Fertigen CAM (Computer Aided Manufacturing) scheint die technische Zeichnung an Bedeutung zu verlieren, da die Verständigung zwischen Konstruktions- und Fertigungsabteilung primär durch den Austausch digitaler Daten erfolgen kann.

  18. Learning by Teaching: Developing Transferable Skills

    ERIC Educational Resources Information Center

    Stollhans, Sascha

    2016-01-01

    "Learning by teaching" (German: "Lernen durch Lehren," commonly abbreviated as "LdL") is a teaching and learning approach which was developed by the French language teacher Jean-Pol Martin in German schools in the 1980s (Martin, 1985). The method sees students in the role of the teacher, and enhances their learning…

  19. Germany’s Chosen Path: Domestic Security Institutions in the Berlin Republic 1990-97.

    DTIC Science & Technology

    1997-12-01

    wird vom Neorealismusparadigma unterstotzt, hier dargestel It durch Kenneth Waltz. Das liberate Paradigma unterstUtzt die Perspektive der "Kultur von Zur... Paradigma folgen. Urn diesen aktuellen Weg in Richtung Realismus zu andern, mul$ Deutschland bestimmte Institutionen verandern oder abschaffen. In der

  20. Neue Anforderungen an den Datenschutz

    NASA Astrophysics Data System (ADS)

    Dix, Alexander

    Eine von der Europäischen Kommission 2003 in Auftrag gegebene Studie hat die rasante technische Entwicklung hin zu "Ambient Intelligence Technologies“ als die größte Herausforderung für den Datenschutz bezeichnet, die sogar größer als die Herausforderung durch den internationalen Terrorismus nach dem 11. September sei.

  1. Energetische Verwertung von Biomasse

    NASA Astrophysics Data System (ADS)

    Zahoransky, Richard; Allelein, Hans-Josef; Bollin, Elmar; Oehler, Helmut; Schelling, Udo

    Etwa 0,1% der Solarenergie wandeln sich durch Photosynthese aus dem Kohlendioxid der Luft in Biomasse um. Die Biomassen sind als Festbrennstoff nutzbar oder zu gasförmigen Brennstoffen weiterverarbeitbar. Zwei Arten von Biomassen sind zu unterscheiden: Anfallende Biomasse

  2. Ermüdungs- und Wachsamkeitsmanagement

    NASA Astrophysics Data System (ADS)

    Ebermann, Hans-Joachim; Murtha, Maria-Pascaline

    1994 wurde erstmals Ermüdung (Fatigue) durch die amerikanische Unfalluntersuchungsbehörde NTSB (National Transportation Safety Board) offiziell als Hauptursache für einen Unfall in der Luftfahrt erklärt. Seitdem wird Müdigkeit bei der Untersuchung von Unfällen systematisch abgefragt.

  3. [Cosmus Conrad Cuno (1652-1745) on a human ectoparasite: the head louse].

    PubMed

    Müller, G H

    1979-07-01

    Cosmus Conrad Cuno, a less well known optician and inventor of microscopes from the second half of the 17th century, published in 1734 at Augsburg his Observationes durch dessen verfertigte Microscopia where along with various observations he communicated salient details pertaining to the biology of the head louse.

  4. Darwin als Sehhilfe für die Psychologie - Evolutionspsychologie

    NASA Astrophysics Data System (ADS)

    Schwab, Frank

    Im Folgenden geht es um Einäugige, stereoskopisches Sehen, weite und enge Horizonte, Monokel und Sonnenbrillen. Der Beitrag versucht die Metapher des Sehens und der Sehhilfen anzuwenden, um so zu verdeutlichen, welchen Gewinn die herkömmliche Psychologie durch die Verwendung einer Darwin'schen Brille erlangen kann.

  5. A study on effects of and stance over tuition fees.

    PubMed

    Karay, Yassin; Matthes, Jan

    2016-01-01

    Zielsetzung: Durch die in Deutschland zurzeit wieder abgeschafften Studiengebühren wurden Nachteile wie z.B. eine verlängerte Studiendauer befürchtet, während der Nachweis eines Nutzens bislang aussteht. Wir haben den Einfluss von Gebühren in Höhe von € 500 pro Semester auf den Studienverlauf Kölner Medizinstudierender sowie deren Einstellung gegenüber diesen Abgaben untersucht.Methodik: Für 1.324 Studierende, die im vorklinischen Studienabschnitt durchweg, zeitweise oder nie Studiengebühren zu zahlen hatten, wurde die Einhaltung der Mindeststudienzeit und die Studienabbrecherquote bis zum ersten Abschnitt der ärztlichen Prüfung analysiert. Mithilfe einer Regressionsanalyse wurden etwaige Effekte durch Studiengebühren und demografische Faktoren untersucht. Zusätzlich beantworteten 400 Studierende in einer online-Befragung Fragen zu ihrer Belastung durch und ihrer Einstellung zu Studiengebühren.Ergebnisse: Studiengebühren hatten keinen erkennbaren Einfluss auf Studiendauer oder Abbrecherquote. Laut Angaben in der online-Befragung wichen zuzeiten der Studiengebühren signifikant mehr Studierende vom vorgeschlagenen Stundenplan ab und sie verwendeten signifikant mehr Zeit darauf, nebenher Geld zu verdienen. 51% der Studierenden, die Gebühren gezahlt hatten und sogar 71% derer, die dies nie mussten, fanden Studiengebühren nicht oder eher nicht gerechtfertigt. Mehr als zwei Drittel der Studierenden konnten keine anhaltende Verbesserung durch Studiengebühren erkennen.Schlussfolgerung: Studiengebühren hatten an der Medizinischen Fakultät zu Köln keinen Einfluss auf Abbrecherquote und Studiendauer. Sie veränderten aber offenbar das Studierverhalten durch die vermehrte Notwendigkeit, neben dem Studium Geld zu verdienen. Die Kölner Medizinstudierenden sahen die Studiengebühren mehrheitlich kritisch und nahmen keinen nachhaltigen Nutzen im Sinne einer Verbesserung der Ausbildungsqualität wahr.

  6. A multiphase mixture model for substrate concentration distribution characteristics and photo-hydrogen production performance of the entrapped-cell photobioreactor.

    PubMed

    Guo, Cheng-Long; Cao, Hong-Xia; Pei, Hong-Shan; Guo, Fei-Qiang; Liu, Da-Meng

    2015-04-01

    A multiphase mixture model was developed for revealing the interaction mechanism between biochemical reactions and transfer processes in the entrapped-cell photobioreactor packed with gel granules containing Rhodopseudomonas palustris CQK 01. The effects of difference operation parameters, including operation temperature, influent medium pH value and porosity of packed bed, on substrate concentration distribution characteristics and photo-hydrogen production performance were investigated. The results showed that the model predictions were in good agreement with the experimental data reported. Moreover, the operation temperature of 30 °C and the influent medium pH value of 7 were the most suitable conditions for photo-hydrogen production by biodegrading substrate. In addition, the lower porosity of packed bed was beneficial to enhance photo-hydrogen production performance owing to the improvement on the amount of substrate transferred into gel granules caused by the increased specific area for substrate transfer in the elemental volume.

  7. From extracellular to intracellular: the establishment of mitochondria and chloroplasts.

    PubMed

    Whatley, J M; John, P; Whatley, F R

    1979-04-11

    Paracoccus and Rhodopseudomonas are unusual among bacteria in having a majority of the biochemical features of mitochondria; blue-green algae have many of the features of chloroplasts. The theory of serial endosymbiosis proposes that a primitive eukaryote successively took up bacteria and blue-green algae to yield mitochondria and chloroplasts respectively. Possible characteristics of transitional forms are indicated both by the primitive amoeba, Pelomyxa, which lacks mitochondria but contains a permanent population of endosymbiotic bacteria, and by several anomalous eukaryotic algae, e.g. Cyanophora, which contain cyanelles instead of chloroplasts. Blue-green algae appear to be obvious precursors of red algal chloroplasts but the ancestry of other chloroplasts is less certain, though the epizoic symbiont, Prochloron, may resemble the ancestral green algal chloroplast. We speculate that the chloroplasts of the remaining algae may have been a eukaryotic origin. The evolution or organelles from endosymbiotic precursors would involve their integration with the host cell biochemically, structurally and numerically.

  8. Purification and functional characterization of thermostable 5-aminolevulinic acid synthases.

    PubMed

    Meng, Qinglong; Zhang, Yanfei; Ma, Chunling; Ma, Hongwu; Zhao, Xueming; Chen, Tao

    2015-11-01

    As 5-aminolevulinic acid synthase (ALAS), the key enzyme for 5-aminolevulinic acid (ALA) synthesis, is unstable, we have sought to find thermostable ALASs from thermophilic organisms. Three ALASs from thermophiles Geobacillus thermoglucosidasius (GT-ALAS), Laceyella sacchari (LS-ALAS) and Pseudomonas alcaliphila (PA-ALAS) were purified and characterized. All enzymes were more stable than two previously studied ALASs from Rhodopseudomonas palustris and Rhodobacter sphaeroides. There was almost no activity change after 60 h at 37 °C for the three thermostable enzymes. This contrasts with the other two enzymes which lost over 90 % activities in just 1 h. Furthermore, the specific activity of LS-ALAS (7.8 U mg(-1)) was also higher than any previously studied ALASs. Thermostable ALASs were found in thermophilic organisms and this paves the way for developing cell free processes for enzymatic production of ALA from bulk chemicals succinate and glycine.

  9. Evolution of the rhodospirillaceae and mitochondria - A view based on sequence data

    NASA Technical Reports Server (NTRS)

    Dayhoff, M. O.; Schwartz, R. M.

    1981-01-01

    New sequence data from several protein families and from 5S ribosomal RNA confirm and elaborate a previously proposed description of the phylogenetic connections between a variety of bacteria and the eukaryotes. Probably, the first organisms were nonphotosynthetic anaerobic prokaryotes, which were followed soon by photosynthetic anaerobes. From this photosynthetic stock, the aerobic line to Pseudomonadacae, Rhodospirillaceae, and blue-greens arose. The eukaryotes derived genetic material from the symbioses of at least three separate bacterial lines. Ancestors of Rhodopseudomonas globiformis gave rise to the eukaryote mitochondria, probably through at least three separate symbioses, one early on the flagellate line, one on the ciliate line, and one on the stem to the multicellular forms.

  10. Engineering aspects of hydrogen production from photosynthetic bacteria

    SciTech Connect

    Herlevich, A.; Karpuk, M.

    1982-02-01

    Certain photosynthetic bacteria (PSB), for example, Rhodopseudomonas capsulata, evolve hydrogen when placed in an anaerobic environment with light and a suitable organic substrate. An engineering effort to use such bacteria for large-scale hydrogen production from sunlight is described. A system to produce 28,000 m/sup 3//day (1 x 10/sup 6/ ft/sup 3//day) of hydrogen has been designed on a conceptual level and includes hydrogen cleanup, substrate storage, and waste disposal. The most critical component in the design is the solar bacterial reactor. Several designs were developed and analyzed. A large covered pond concept appears most attractive. Cost estimates for the designs show favorable economics.

  11. Breakdown of food waste by anaerobic fermentation and non-oxygen producing photosynthesis using a photosynthetic bacterium.

    PubMed

    Mekjinda, N; Ritchie, R J

    2015-01-01

    Large volumes of food waste are produced by restaurants, hotels, etc generating problems in its collection, processing and disposal. Disposal as garbage increases the organic matter in landfills and leachates. The photosynthetic bacterium Rhodopseudomonas palustris (CGA 009) easily broke down food waste. R. palustris produces H2 under anaerobic conditions and digests a very wide range of organic compounds. R. palustris reduced BOD by ≈70% and COD by ≈33%, starch, ammonia, nitrate, was removed but had little effect on reducing sugar or the total phosphorus, lipid, protein, total solid in a 7-day incubation. R. palustris produced a maximum of 80ml H2/g COD/day. A two-stage anaerobic digestion using yeast as the first stage, followed by a R. palustris digestion was tested but production of H2 was low.

  12. Formation and hydrogen production of photosynthetic bacterial biofilm under various illumination conditions.

    PubMed

    Liao, Qiang; Wang, Ye-Jun; Wang, Yong-Zhong; Zhu, Xun; Tian, Xin; Li, Jun

    2010-07-01

    The application of immobilized-cell technology in photobioreactor for hydrogen production could offer improvements in photo-hydrogen production rate and light utilization efficiency. Indigenous Rhodopseudomonas palustris CQK 01 was attached to the surface of a cover glass slide in a flat-panel photobioreactor, to form biofilm under illumination with a range of intensities and wavelengths. The morphology and structure of mature photosynthetic bacterial (PSB) biofilm were determined to elucidate the relationship between biofilm formation and hydrogen production performance. The effects of operation conditions on hydrogen production performance of the biofilms formed under various illumination conditions were experimentally investigated. The results showed that illumination wavelength and intensity substantially influenced the morphology and structure of the biofilm, and the hydrogen production performance of mature biofilm varied significantly with the illumination conditions that were used for biofilm formation. Biofilm formed under 590 nm and 5000 lx illumination showed the highest hydrogen production performance. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  13. Multichannel carotenoid deactivation in photosynthetic light harvesting as identified by an evolutionary target analysis.

    PubMed

    Wohlleben, Wendel; Buckup, Tiago; Herek, Jennifer L; Cogdell, Richard J; Motzkus, Marcus

    2003-07-01

    A new channel of excitation energy deactivation in bacterial light harvesting was recently discovered, which leads to carotenoid triplet population on an ultrafast timescale. Here we show that this mechanism is also active in LH2 of Rhodopseudomonas acidophila through analysis of transient absorption data with an evolutionary target analysis. The algorithm offers flexible testing of kinetic network models with low a priori knowledge requirements. It applies universally to the simultaneous fitting of target state spectra and rate constants to time-wavelength-resolved data. Our best-fit model reproduces correctly the well-known cooling and decay behavior in the S(1) band, but necessitates an additional, clearly distinct singlet state that does not exchange with S(1), promotes ultrafast triplet population and participates in photosynthetic energy transfer.

  14. Arsenic removal from contaminated soil via biovolatilization by genetically engineered bacteria under laboratory conditions.

    PubMed

    Liu, Shuang; Zhang, Fan; Chen, Jian; Sun, Guoxin

    2011-01-01

    In Rhodopseudomonas palustris, an arsM gene, encoding bacterial and archaeal homologues of the mammalian Cyt19 As(III) S-adenosylmethionine methytransferase, was regulated by arsenicals. An expression of arsM was introduced into strains for the methylation of arsenic. When arsM was expressed in Sphingomonas desiccabilis and Bacillus idriensis, it had 10 folds increase of methyled arsenic gas compared to wild type in aqueous system. In soil system, about 2.2%-4.5% of arsenic was removed by biovolatilization during 30 days. This study demonstrated that arsenic could be removed through volatilization from the contaminated soil by bacteria which have arsM gene expressed. These results showed that it is possible to use microorganisms expressing arsM as an inexpensive, efficient strategy for arsenic bioremediation from contaminated water and soil.

  15. Controlled Microbial Cenoses in Closed Spaces

    NASA Astrophysics Data System (ADS)

    Somova, Lydia; Mikheeva, Galina

    Controlled microbial cenoses have good prospects in closed spaces: for air treatment in LSS and cellars industrial premises; for sewage treatment in LSS; for increase of productivity and protect of plants from infections in LSS. Possible methods of formation of microbiocenoses are: selection, autoselection, artificial formation taking into account their biochemical properties and metabolic interactions. Experimental microbiocenoses, has been produced on the basis of natural association of microorganisms by long cultivation on specially developed medium. Dominating groups are bacteria of genera: Lactobacillus, Streptococcus, Leuconostoc, Bidobac-terium, Rhodopseudomonas and yeast of genera: Kluyveromyces, Saccharomyces and Torulop-sis. Microbiocenoses do not contain pathogenic and conditionally pathogenic microorganisms, they possess opposing and probiotic properties. Different examples of microbial cenoses actions are to be presented in the paper.

  16. Highly ordered crystals of channel-forming membrane proteins, of nucleoside-monophosphate kinases, of FAD-containing oxidoreductases and of sugar-processing enzymes and their mutants

    NASA Astrophysics Data System (ADS)

    Schulz, G. E.; Dreyer, M.; Klein, C.; Kreusch, A.; Mittl, P.; Mu¨ller, C. W.; Mu¨ller-Dieckmann, J.; Muller, Y. A.; Proba, K.; Schlauderer, G.; Spu¨rgin, P.; Stehle, T.; Weiss, M. S.

    1992-08-01

    Preparation and crystallization procedures as well as crystal properties are reported for 12 proteins plus numerous site-directed mutants. The proteins are: the integral membrane protein porin from Rhodobacter capsulatus which diffracts to at least 1.8A˚resolution, porin from Rhodopseudomonas blastica which diffracts to at least 2.0A˚resolution, adenylate kinase from yeast and mutants, adenylate kinase from Escherichia coli and mutants, bovine liver mitochondrial adenylate kinase, guanylate kinase from yeast, uridylate kinase from yeast, glutathione reductase from E. coli and mutants, NADH peroxidase from Streptococcus faecalis containing a sulfenic acid as redox-center, pyruvate oxidase from Lactobacillus plantarum containing FAD and TPP, cyclodextrin glycosyltransferase from Bacillus circulans and mutants, and a fuculose aldolase from E. coli.

  17. Single-Molecule Spectroscopy Unmasks the Lowest Exciton State of the B850 Assembly in LH2 from Rps. acidophila

    PubMed Central

    Kunz, Ralf; Timpmann, Kõu; Southall, June; Cogdell, Richard J.; Freiberg, Arvi; Köhler, Jürgen

    2014-01-01

    We have recorded fluorescence-excitation and emission spectra from single LH2 complexes from Rhodopseudomonas (Rps.) acidophila. Both types of spectra show strong temporal spectral fluctuations that can be visualized as spectral diffusion plots. Comparison of the excitation and emission spectra reveals that for most of the complexes the lowest exciton transition is not observable in the excitation spectra due to the cutoff of the detection filter characteristics. However, from the spectral diffusion plots we have the full spectral and temporal information at hand and can select those complexes for which the excitation spectra are complete. Correlating the red most spectral feature of the excitation spectrum with the blue most spectral feature of the emission spectrum allows an unambiguous assignment of the lowest exciton state. Hence, application of fluorescence-excitation and emission spectroscopy on the same individual LH2 complex allows us to decipher spectral subtleties that are usually hidden in traditional ensemble spectroscopy. PMID:24806933

  18. A fiber-optic sensor for accurately monitoring biofilm growth in a hydrogen production photobioreactor.

    PubMed

    Zhong, Nianbing; Liao, Qiang; Zhu, Xun; Chen, Rong

    2014-04-15

    A new simple fiber-optic evanescent wave sensor was created to accurately monitor the growth and hydrogen production performance of biofilms. The proposed sensor consists of two probes (i.e., a sensor and reference probe), using the etched fibers with an appropriate surface roughness to improve its sensitivity. The sensor probe measures the biofilm growth and change of liquid-phase concentration inside the biofilm. The reference probe is coated with a hydrophilic polytetrafluoroethylene membrane to separate the liquids from photosynthetic bacteria Rhodopseudomonas palustris CQK 01 and to measure the liquid concentration. We also developed a model to demonstrate the accuracy of the measurement. The biofilm measurement was calibrated using an Olympus microscope. A linear relationship was obtained for the biofilm thickness range from 0 to 120 μm with a synthetic medium under continuous supply to the bioreactor. The highest level of hydrogen production rate occurred at a thickness of 115 μm.

  19. Two regimens of electrogenic cyclic redox chain operation in chromatophores of non-sulfur purple bacteria. A study using antimycin A.

    PubMed

    Remennikov, V G; Samuilov, V D

    1979-11-08

    Antimycin A causes a biphasic suppression of the light-induced membrane potential generation in Rhodospirillum rubrum and Rhodopseudomonas sphaeroides chromatophores incubated anerobically. The first phase is observed at low antibiotic concentrations and is apparently due to its action as a cyclic electron transfer inhibitor. The second phase is manifested at concentrations which are greater than 1--2 muM and is due to uncoupling that may be connected with an antibiotic-induced dissipation of the electrochemical H+ gradient across the chromatophore membrane. The inhibitory effect of antimycin added at low concentrations under aerobic conditions is removed by succinate to a large extent. It is expected that the electrogenic cyclic redox chain in the bacterial chromatophores incubed under conditions of continuous illumination may function at two regimes: (1) as a complete chain involving all the redox components, and (2) as a shortened chain involving only the P-870 photoreaction center, ubiquinone and cytochrome c2.

  20. Evolution of the rhodospirillaceae and mitochondria - A view based on sequence data

    NASA Technical Reports Server (NTRS)

    Dayhoff, M. O.; Schwartz, R. M.

    1981-01-01

    New sequence data from several protein families and from 5S ribosomal RNA confirm and elaborate a previously proposed description of the phylogenetic connections between a variety of bacteria and the eukaryotes. Probably, the first organisms were nonphotosynthetic anaerobic prokaryotes, which were followed soon by photosynthetic anaerobes. From this photosynthetic stock, the aerobic line to Pseudomonadacae, Rhodospirillaceae, and blue-greens arose. The eukaryotes derived genetic material from the symbioses of at least three separate bacterial lines. Ancestors of Rhodopseudomonas globiformis gave rise to the eukaryote mitochondria, probably through at least three separate symbioses, one early on the flagellate line, one on the ciliate line, and one on the stem to the multicellular forms.

  1. Photosynthetic bacteria-based membrane bioreactor as post-treatment of an anaerobic membrane bioreactor effluent.

    PubMed

    González, E; Díaz, O; Ruigómez, I; de Vera, C R; Rodríguez-Gómez, L E; Rodríguez-Sevilla, J; Vera, L

    2017-09-01

    Anaerobic membrane bioreactors have attracted increasing interest in the field of wastewater treatment. However, significant amounts of organic matter, nitrogen and sulphide in the effluent may limit its reuse. A photosynthetic bacteria-based membrane bioreactor is proposed for the further treatment of this effluent. A pilot-scale unit was run outdoor for over 900h to assess the process performance at short hydraulic retention time. After an initial biomass development, simultaneous removal of soluble organic matter and nitrogen was achieved (65% and 39%, respectively). In addition, a significant concentration of sulphate was detected in the permeate, revealing an evident sulphide oxidation. Despite the accumulation of biopolymer clusters in the biological suspension, membrane fouling was effectively mitigated by air-aided backwashing, allowing a sustainable operation. Several strains of bacteria were identified including the photoheterotrophic bacteria Rhodopseudomonas sp. and the nitrifying and denitrifying bacteria Chryseobacterium sp. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Microbial Protein-Protein Interactions (MiPPI) Data from the Genomics: GTL Center for Molecular and Cellular Systems (CMCS)

    DOE Data Explorer

    The Genomic Science Center for Molecular and Cellular Systems (CMCS), established in 2002, seeks to identify and characterize the complete set of protein complexes within a cell to provide a mechanistic basis for the understanding of biochemical functions. The CMCS is anchored at ORNL and PNNL. CMCS initially focused on the identification and characterization of protein complexes in two microbial systems,Rhodopseudomonas palustris (R. palustris) and Shewanella oneidensis (S. oneidensis). These two organisms have also been the focus of major DOE Genomic Science/Microbial Cell Program (MCP) projects. To develop an approach for identifying the diverse types of complexes present in microbial organisms, CMCS incorporates a number of molecular biology, microbiology, analytical and computational tools in an integrated pipeline.

  3. Neural network modeling of the light profile in a novel photobioreactor.

    PubMed

    Salazar-Peña, R; Alcaraz-González, V; González-Álvarez, V; Snell-Castro, R; Méndez-Acosta, H O

    2014-06-01

    An artificial neural network (ANN) was implemented to model the light profile pattern inside a photobioreactor (PBR) that uses a toroidal light arrangement. The PBR uses Tequila vinasses as culture medium and purple non-sulfur bacteria Rhodopseudomonas palustris as biocatalyzer. The performance of the ANN was tested for a number of conditions and compared to those obtained by using deterministic models. Both ANN and deterministic models were validated experimentally. In all cases, at low biomass concentration, model predictions yielded determination coefficients greater than 0.9. Nevertheless, ANN yielded the more accurate predictions of the light pattern, at both low and high biomass concentration, when the bioreactor radius, the depth, the rotational speed of the stirrer and the biomass concentration were incorporated in the ANN structure. In comparison, most of the deterministic models failed to correlate the empirical data at high biomass concentration. These results show the usefulness of ANNs in the modeling of the light profile pattern in photobioreactors.

  4. Synergistic Effect of Photosynthetic Bacteria and Isolated Bacteria in Their Antifungal Activities against Root Rot Fungi.

    PubMed

    Wei, Hongyi; Okunishi, Suguru; Yoshikawa, Takeshi; Kamei, Yuto; Dawwoda, Mahmoud A O; Santander-DE Leon, Sheila Mae S; Nuñal, Sharon Nonato; Maeda, Hiroto

    2016-01-01

    Antifungal bacteria (AB) in root rot fungus (RRF)-contaminated sweet potato farms were isolated, and seven strains were initially chosen as antagonistic candidates. An antagonistic test by using the mycelial disk placement method revealed that one AB strain by itself could inhibit the RRF growth. This AB strain was identified as Bacillus polyfermenticus based on phylogeny of 16S ribosomal RNA genes. Two AB strains (Bacillus aerophilus) displayed high levels of antifungal activity when paired with photosynthetic bacterial strain A (a purple nonsulfur photosynthetic bacterium Rhodopseudomonas faecalis). The results suggest the possible use of the isolates as agents for the biological control of the RRF infection of agricultural products in fields of cultivation.

  5. Exhaustive Database Searching for Amino Acid Mutations in Proteomes

    SciTech Connect

    Hyatt, Philip Douglas; Pan, Chongle

    2012-01-01

    Amino acid mutations in proteins can be found by searching tandem mass spectra acquired in shotgun proteomics experiments against protein sequences predicted from genomes. Traditionally, unconstrained searches for amino acid mutations have been accomplished by using a sequence tagging approach that combines de novo sequencing with database searching. However, this approach is limited by the performance of de novo sequencing. The Sipros algorithm v2.0 was developed to perform unconstrained database searching using high-resolution tandem mass spectra by exhaustively enumerating all single non-isobaric mutations for every residue in a protein database. The performance of Sipros for amino acid mutation identification exceeded that of an established sequence tagging algorithm, Inspect, based on benchmarking results from a Rhodopseudomonas palustris proteomics dataset. To demonstrate the viability of the algorithm for meta-proteomics, Sipros was used to identify amino acid mutations in a natural microbial community in acid mine drainage.

  6. Emission spectra of LH2 complex: full Hamiltonian model

    NASA Astrophysics Data System (ADS)

    Heřman, Pavel; Zapletal, David; Horák, Milan

    2013-05-01

    In the present contribution we study the absorption and steady-state fluorescence spectra for ring molecular system, which can model B850 ring of peripheral light-harvesting complex LH2 from purple bacterium Rhodopseudomonas acidophila (Rhodoblastus acidophilus). LH2 is a highly symmetric ring of nine pigment-protein subunits, each containing two transmembrane polypeptide helixes and three bacteriochlorophylls (BChl). The uncorrelated diagonal static disorder with Gaussian distribution (fluctuations of local excitation energies) simultaneously with the diagonal dynamic disorder (interaction with a bath) in Markovian approximation is used in our simulations. We compare calculated absorption and steady state fluorescence spectra obtained within the full Hamiltonian model of the B850 ring with our previous results calculated within the nearest neighbour approximation model and also with experimental data.

  7. Primary structure determination of two cytochromes c2: close similarity to functionally unrelated mitochondrial cytochrome C.

    PubMed Central

    Ambler, R P; Meyer, T E; Kamen, M D

    1976-01-01

    The amino-acid sequences of the cytochromes c2 from the photosynthetic non-sulfur purple bacteria Rhodomicrobium vannielii and Rhodopseudomonas viridis have been determined. Only a single residue deletion (at position 11 in horse cytochrome c) is necessary to align the sequences with those of mitochondrial cytochromes c. The overall sequence similarity between these cytochromes c2 and mitochondrial cytochromes c is closer than that between mitochondrial cytochromes c and the other cytochromes c2 of known sequence, and in the latter multiple insertions and deletions must be postulated before a match can be obtained. Nevertheless, these two cytochromes c2 show no better reactivity with the mitochondrial cytochrome c oxidase than do the less well-matched cytochromes c2. The bearing of these findings on possible evolutionary relationship between mitochondria and prokaryotes is discussed. PMID:174109

  8. Theory of excitation energy transfer in the primary processes of photosynthesis. II. Group symmetry analysis of the bacterial light-harvesting complex

    NASA Astrophysics Data System (ADS)

    Skala, L.; Jungwirth, P.

    1989-10-01

    A group symmetry analysis of the Pauli master equation for the excitation energy transfer in the cyclic arrangement of N ( N= 6- 36) antenna Bchl molecules surrounding the bacterial reaction center of Rhodopseudomonas viridis is performed. The group theory allows to find analytic expressions for the most important observables (the antenna and reaction center fluorescence intensities and the quantum yield of the transfer to the charge transfer state) and to express their dependence on N. The time dependence of the fluorescence intensities is given by two exponentials, however, a single-exponential approximation can be used for t> t0 = 4-25 ps. The quantum yield of the excitation energy transfer to the reaction center charge transfer state is high (0.71- 0.98) for the whole range of physically acceptable values of the Förster radius R0 = 46-96 Å.

  9. Photoproduction of H/sub 2/ from cellulose by an anaerobic bacterial coculture

    SciTech Connect

    Odom, J.M.; Wall, J.D.

    1983-04-01

    Cellulomonas sp. strain ATCC 21399 is a facultatively anaerobic, cellulose-degrading microorganism that does not evolve hydrogen but produces organic acids during cellulose fermentation. Rhodopseudomonas capsulata cannot utilize cellulose, but grows photoheterotrophically under anaerobic conditions on organic acids or sugars. This report describes an anaerobic coculture of the Cellulomonas strain with wild-type R. capsulata or a mutant strain lacking uptake hydrogenase, which photoevolves molecular hydrogen by the nitrogenase system of R. capsulata with cellulose as the sole carbon source.In coculture, the hydrogenase-negative mutant produced 4.6 to 6.2 mol of H/sub 2/ per mol of glucose equivalent, compared with 1.2 to 4.3 mol for the wild type.

  10. Redox cycling of Fe(II) and Fe(III) in magnetite by Fe-metabolizing bacteria

    NASA Astrophysics Data System (ADS)

    Byrne, James M.; Klueglein, Nicole; Pearce, Carolyn; Rosso, Kevin M.; Appel, Erwin; Kappler, Andreas

    2015-03-01

    Microorganisms are a primary control on the redox-induced cycling of iron in the environment. Despite the ability of bacteria to grow using both Fe(II) and Fe(III) bound in solid-phase iron minerals, it is currently unknown whether changing environmental conditions enable the sharing of electrons in mixed-valent iron oxides between bacteria with different metabolisms. We show through magnetic and spectroscopic measurements that the phototrophic Fe(II)-oxidizing bacterium Rhodopseudomonas palustris TIE-1 oxidizes magnetite (Fe3O4) nanoparticles using light energy. This process is reversible in co-cultures by the anaerobic Fe(III)-reducing bacterium Geobacter sulfurreducens. These results demonstrate that Fe ions bound in the highly crystalline mineral magnetite are bioavailable as electron sinks and electron sources under varying environmental conditions, effectively rendering magnetite a naturally occurring battery.

  11. The light intensity under which cells are grown controls the type of peripheral light-harvesting complexes that are assembled in a purple photosynthetic bacterium

    SciTech Connect

    Brotosudarmo, Tatas H. P.; Collins, Aaron M.; Gall, Andrew; Roszak, Aleksander W.; Gardiner, Alastair T.; Blankenship, Robert E.; Cogdell, Richard J.

    2011-11-15

    The differing composition of LH2 (peripheral light-harvesting) complexes present in Rhodopseudomonas palustris 2.1.6 have been investigated when cells are grown under progressively decreasing light intensity. Analysis of the absorption spectra reveals there must be more than two types of LH2 complexes present. Purified HL (high-light) and LL (low-light) LH2 complexes have mixed apoprotein compositions. The HL complexes contain PucABa and PucABb apoproteins. The LL complexes contain PucABa, PucABd and PucBb-only apoproteins. This mixed apoprotein composition can explain their resonance Raman spectra.

  12. Excitation energy transfer of Light-harvesting complex II of purple photosynthetic bacteria: the role of S1 state of carotenoids

    NASA Astrophysics Data System (ADS)

    Hsu, Chao-Ping; Fleming, Graham R.; Head-Gordon, Martin

    2001-03-01

    With time-dependent density functional theory (TDDFT), the excitation energy transfer coupling (Coulomb coupling) is obtained for the S1 state of rhodopin glucoside (RG) and Qy of bacteriochlorophylls (BChl) in the light-harvesting complex II (LH2) of purple photosynthetic bacterium Rhodopseudomonas acidophila. Our results suggest the small mixing of S2 (B_u) character from symmetry-breaking of carotenoid structure plays an important role in the Coulomb coupling. As a result the coupling to chlorophylls are similar to a set of scaled down S_2-Qy couplings. Using a exciton model with disorder for site energy for BChls, the calculated coupling strengths yields Car(S_1)-to-BChl(Q_y) excitation energy transfer time of 1.2 ps for Rhodobacter sphaeroides which is in good agreement with recent experimental results (2.4 ps).

  13. Integrative control of carbon, nitrogen, hydrogen, and sulfur metabolism: the central role of the Calvin-Benson-Bassham cycle.

    PubMed

    Laguna, Rick; Joshi, Gauri S; Dangel, Andrew W; Luther, Amanda K; Tabita, F Robert

    2010-01-01

    Nonsulfur purple (NSP) photosynthetic bacteria use the Calvin-Benson-Bassham (CBB) reductive pentose phosphate pathway for the reduction of CO(2) via ribulose 1,5-bisphosphate (RuBP) carboxylase-oxygenase (RubisCO), as a means to build cell mass during chemoautotrophic or photoautotrophic conditions. In addition, the CBB pathway plays an important role in maintaining redox balance during photoheterotrophic growth conditions. In this communication we describe protein-protein interactions between two transcriptional regulators CbbR and RegA and the possible role of the CbbX protein in regulating the CBB pathway in Rhodobacter sphaeroides. In Rhodopseudomonas palustris, the CbbR and the CbbRRS system (a three-protein, two-component regulatory system) regulate the CBB pathway. Moreover, derepression of the nitrogenase complex, and the production of hydrogen gas, appears to be a common mechanism to balance the redox potential in RubisCO-compromised strains of NSP photosynthetic bacteria.

  14. GeO2-SiO2-chitosan-medium-coated hollow optical fiber for cell immobilization.

    PubMed

    Zhong, Nian-Bing; Zhu, Xun; Liao, Qiang; Wang, Yong-Zhong; Chen, Rong

    2013-08-15

    A GeO(2)-SiO(2)-chitosan-medium (GSCM)-coated hollow optical fiber (HOF) is proposed. The HOF consists of three parts: the fiber core (air), cladding (SiO(2)), and coating (GSCM), which shows the highest refractive index of the three. The HOF's luminescence properties and surface morphology are investigated. Their adsorption capacity for Rhodopseudomonas palustris CQK 01 is also assayed. We discovered that when the amount of 2GeO(2)-SiO(2) sol dopant is 0.9 mass percent, the HOF exhibits the highest luminous intensity and uniform light distribution, and the adsorption capacity for the cell is 3.2 times higher than that of a normal solid optical fiber.

  15. Redox cycling of Fe(II) and Fe(III) in magnetite by Fe-metabolizing bacteria.

    PubMed

    Byrne, James M; Klueglein, Nicole; Pearce, Carolyn; Rosso, Kevin M; Appel, Erwin; Kappler, Andreas

    2015-03-27

    Microorganisms are a primary control on the redox-induced cycling of iron in the environment. Despite the ability of bacteria to grow using both Fe(II) and Fe(III) bound in solid-phase iron minerals, it is currently unknown whether changing environmental conditions enable the sharing of electrons in mixed-valent iron oxides between bacteria with different metabolisms. We show through magnetic and spectroscopic measurements that the phototrophic Fe(II)-oxidizing bacterium Rhodopseudomonas palustris TIE-1 oxidizes magnetite (Fe3O4) nanoparticles using light energy. This process is reversible in co-cultures by the anaerobic Fe(III)-reducing bacterium Geobacter sulfurreducens. These results demonstrate that Fe ions bound in the highly crystalline mineral magnetite are bioavailable as electron sinks and electron sources under varying environmental conditions, effectively rendering magnetite a naturally occurring battery. Copyright © 2015, American Association for the Advancement of Science.

  16. [Biological characteristics and phylogenetic analysis of a denitrifying photosynthetic bacterium].

    PubMed

    Chen, Hui; Zhang, Demin; Wang, Longgang; Pan, Zhichong

    2011-02-01

    Nitrite accumulation in aquaculture water is toxic to reared animals. One of the solutions to this problem is to apply denitrifying bacteria. This paper is intended to get a strain of phototrophic bacteria for efficient removal of nitrite from aquaculture water. We used soft agar to isolate and purify phototrophic bacteria. We investigated biological characteristics of the isolate by means of light and electronic observations, physical and chemical tests. We analyzed its phylogenetical position based on the sequences of 16S rDNA and the gene that codes for photosynthetic reaction center subunit M (pufM). A photosynthetic bacterial strain, named wps, showing high removal efficiency of nitrite, was isolated from the freshwater ponds. Cells were Gram-negative, rod-shaped, slightly curved, 0.4 - 0.6 x 1.5 - 4.0 microm, motile by means of polar multiple flagella. Intracellular membranes were of the lamellar type. It grew under facultative anaerobic conditions in the light with bacteriochlorophyll a and carotenoid of sppirilloxanthin series as photosynthetic pigment. The optimum growth was obtained at pH 5.5 - 8.5, in a range of 0 - 2% salinity and at 25 - 38 degrees C. The similarity of 16S rDNA between strain wps and Rhodopseudomonas palustris was 98.9% and 94.9% for pufM gene. However, there are significant differences between them in the morphological and physiological characteristics, i. e. grew at pH 5.5; no growth photoautotrophicaly with sodium hydrogen carbonate; could not utilize citrate or formate as only carbon source; required thiamine hydrochloride and calcium pantothenate as growth factors. Strain wps may represent a novel species in genus Rhodopseudomonas and possibly find its application in the bioremediation of polluted aquaculture water.

  17. Ein Unscented Kalman Filter zur Schätzung von Schaltungsnichtidealitäten eines zeitkontinuierlichen Sigma-Delta Wandlers mit impliziter Dezimation

    NASA Astrophysics Data System (ADS)

    Buhmann, A.; Keller, M.; Maurer, M.; Ortmanns, M.; Manoli, Y.

    2008-05-01

    Nichtidealitäten einer Schaltung, wie z.B. nicht ideale Charakteristik des Operationsverstärkers und Streuungen in den Filterkoeffizienten, sind dahingehend bekannt die Effizienz von zeitkontinuierlichen Sigma-Delta Wandlern in drastischer Weise zu reduzieren. Daher stellt diese Veröffentlichung eine mögliche Methode vor, um die genannten Nichtidealitäten durch eine Schätzung mit Hilfe eines Unscented Kalman Filters zu bestimmen und in einem möglichen weiteren Schritt zu korrigieren. Des Weiteren kann durch eine leichte Modifikation des vorgestellten Algorithmus auch gleichzeitig eine implizite Dezimation des Ausgangssignals durchgeführt werden. Hierdurch wird die Gesamteffizienz des vorgestellten Ansatzes gesteigert, da kein zusätzlicher Dezimationsfilter mehr benötigt wird. Simulationsergebnisse des Filteralgorithmus zeigen die prinzipielle Funktion des Algorithmus.

  18. Nichtrigide Bildregistrierung für die adaptive Strahlentherapie mittels Free Form Deformation

    NASA Astrophysics Data System (ADS)

    Wurst, Gernot; Bendl, Rolf

    Im Rahmen der Adaptiven Strahlentherapie müssen zum Behandlungszeitpunkt Abweichungen der aktuellen Patientengeometrie von den Planungsdaten bekannt sein, damit eine Anpassung des Bestrahlungsplans vorgenommen werden kann. State of the Art ist in diesem Zusammenhang die rigide Registrierung von Planungs- und Kontrolldaten. Hierbei werden jedoch komplexere, nichtrigide Deformationen nicht angemessen berücksichtigt. Daher wurde ein Verfahren entwickelt, das diese komplexen Deformationen durch ein Free Form-Deformationsmodell beschreibt. Die dafür vorzugebenden Translationsvektoren wurden durch Template Matching bestimmt. Es zeigte sich, dass die vorhandenen Deformationen weitgehend erkannt werden. Weiterhin ist das Verfahren aufgrund seines günstigen Laufzeitverhaltens prädestiniert für die Adaptive Strahlentherapie.

  19. Einführung in die Renaturierungsökologie

    NASA Astrophysics Data System (ADS)

    Zerbe, Stefan; Wiegleb, Gerhard; Rosenthal, Gert

    Durch die übernutzung der Naturressourcen sind heute weltweit viele natürliche wie auch durch Kultur entstandene ökosysteme und Landschaften in ihren Funktionen und Leistungen stark beeinträchtigt oder sogar völlig zerstört. Bereits vor mehr als einem Jahrzehnt konstatierte (1995), dass ca. 45 % der terrestrischen Landoberfläche nur eine reduzierte Kapazität für die zukünftige Landnutzung haben. Als Grund hob er eine in der Vergangenheit nicht nachhaltige Landbewirtschaftung hervor. Mit einer gezielten Renaturierung der betroffenen ökosysteme soll dieser Trend umgekehrt werden (Harris und van Diggelen 2006). Vor diesem Hintergrund ist die ökosystemrenaturierung (ecological restoration) wichtiger Bestandteil der Planungs- und Naturschutzpraxis in Mitteleuropa und die Renaturierungsökologie (restoration ecology) zu einer eigenen wissenschaftlichen Arbeitsrichtung geworden.

  20. Anwendungsorientierte Funktionswerkstoffe mittels Walzplattieren

    NASA Astrophysics Data System (ADS)

    Reichelt, Stephan; Schmidt, J.-F.; Neubauer, M.; Schade, A.; Andler, G.; Buerkle, G.; Hansen, H.; Hofmann, L.; Stiehler, J.; Janisch, S. D.

    Obwohl walzplattierte Werkstoffe in der allgemeinen Öffentlichkeit nur wenig beachtet und behandelt werden, besitzen sie bereits heute eine hohe Bedeutung, um unterschiedliche Güter des täglichen Bedarfs realisieren und produzieren zu können. Durch eine hohe Produktivität und ein umfangreiches technologisches Wissen lassen sich bereits heute sehr anspruchsvolle und aufwändige Funktionswerkstoffe mittels Plattierverfahren herstellen, die maßgeschneiderte Produkteigenschaften für viele Halbzeuge und Fertigprodukte garantieren. Bedingt durch die konstruktiven Trends im Bereich von Automotive, Luft- und Raumfahrt sowie dem allgemeinen konstruktiven und materiellem Leichtbau ist davon auszugehen, dass die Bedeutung maßgeschneiderter Funktionswerkstoffe für spezifische Anwendungsfelder in naher Zukunft weiter wachsen und die Bedeutung einzelner Plattierverfahren für eine wirtschaftliche Produktionskette verschiedener Produkte wachsen wird.

  1. Positive Werkzeuge mit hohem IQ

    NASA Astrophysics Data System (ADS)

    Luik, Matthias

    Fräsen ist ein Verfahren, auf welches im modernen Produktionsprozess nicht verzichtet werden kann. Dabei stellt die zunehmende Komplexität der zu fertigenden Bauteile ganz neue Herausforderungen an ein Werkzeug. Konnten früher Bauteile nur mit hohem Aufwand durch Erodieren oder Außenräumen hergestellt werden, müssen heute bereits Fräswerkzeuge für solche Bearbeitungsaufgaben aus Zeitund Kostengründen eingesetzt werden. Dies führt dazu, dass viele Bauteile heute in einer Aufspannung bearbeitbar sind, welche früher nur durch mehrmaliges Umspannen erzeugt werden konnten. Um Bearbeitungszeiten und -kosten dabei gering zu halten, müssen aber dennoch universelle Werkzeuge eingesetzt werden, welche für verschiedenste Bearbeitungsaufgaben ausgelegt sind.

  2. Zeitspiel ist keine Alternative - Warum der Wandel zur Pflicht wird

    NASA Astrophysics Data System (ADS)

    Dieper, Stephan

    "Wege entstehen dadurch, dass man sie geht." (Franz Kafka) Die Welt der Digitalisierung ist voll von Wegen, die jemand gegangen ist, bevor dort ein Weg war. Manche dieser Wege stellten sich als Sackgasse heraus, manche als Abkürzung und aus anderen wurden ganze Wegenetze und Städte. Die Energiewelt wird durch den digitalen Wandel nicht verschont bleiben. Durch die intelligenten Messsysteme und die zugehörigen, neuen Strukturen werden energiefremden Wettbewerbern Chancen zum Markteintritt eröffnet. EVUs müssen sich darauf einstellen, dass der permanente Wandel nicht mehr enden wird. Doch auch den EVUs eröffnen sich Optionen. Um erfolgreich zu sein, müssen sie lernen loszugehen, ohne das genaue Ziel zu kennen.

  3. Eine FPAA-Architektur zur rekonfigurierbaren Instantiierung von zeitkontinuierlichen Analogfiltern

    NASA Astrophysics Data System (ADS)

    Becker, J.; Manoli, Y.

    2005-05-01

    Im Folgenden wird eine neue Methodik von FPAAs (Field Programmable Analog Arrays) gezeigt, die speziell für die Instantiierung von zeitkontinuierlichen (continuous-time, CT) Analogfiltern in Hardware entwickelt wurde. Die Chiptopologie beinhaltet 17 digital konfigurierbare analoge Blöcke (configurable analog blocks, CABs), die durch ein hexagonales Netzwerk miteinander verbunden sind. Jeder CAB ist aus einstellbaren Gm-C Integratoren aufgebaut, welche das analoge Signal sowohl formen und seinen Weg durch die Matrix festlegen, gleichzeitig aber auch die Grundbausteine für zeitkontinuierliche Hochfrequenzfilter darstellen. Intelligente Pufferspeicher für die Ein-/Ausgänge (IO-buffer) garantieren die Rekonfigurierung der Matrix mit minimaler Störung des kontinuierlichen Analogsignals. Die Architektur wird als Hardwareplattform für beliebige Schaltungen, welche aus einer gegebenen Anzahl an Gm-C-Zellen bestehen, eingeführt und verifiziert bevor eine exemplarische Instantiierung eines Butterworth Filters 4. Ordnung in Biquad Anordnung gezeigt wird.

  4. Die Struktur von schlankem Materialfluss mit Lean Production Kanban und Innovationen

    NASA Astrophysics Data System (ADS)

    Scheid, Wolf-Michael

    In der Literatur wird Materialfluss überwiegend in Spezialdisziplinen betrachtet, etwa der Steuerungslogik, der Logistiktechnik oder dem Supply Chain Management. Ein charakterisierendes Merkmal des Materialflusses ist jedoch, dass er sich aus vielfältigen Einzelbausteinen zusammensetzt, die alle harmonisch abgestimmt sein müssen. Die maximal erreichbare Effizienz wird nicht durch Höchstleistungen in dem einen oder anderen Spezialthema bestimmt, sondern durch das schwächste Glied im gesamten komplexen Netzwerk. Den Schnittstellen zwischen den betroffenen Fachbereichen in einem Unternehmen kommt hier eine ganz besondere Bedeutung zu: Erst ein harmonischer Einklang ermöglicht hohe Effektivität. Dies setzt umfassendes Verständnis für interdisziplinäre Notwendigkeiten, ein hohes Maß an Abstimmung mit den operativen Prozessen und letztlich einen einvernehmlichen Umgang und den Respekt vor den Problemstellungen des Anderen voraus.

  5. Toolmanagement - Werkzeuge und Prozesse als Schlüssel für eine effiziente Produktion

    NASA Astrophysics Data System (ADS)

    Enßle, Magnus

    In Bezug auf die Fertigungskosten nehmen die Werkzeugkosten mit 3% einen sehr kleinen und daher vermeintlich unwichtigen Posten ein. HoheKosten ergeben sich aber meist indirekt durch Maschinenstillstandszeiten wegen fehlender oder falscher Werkzeuge, wegen ineffektiven Rüstvorgängen, umständlicher Werkzeuglogistik, unnötig hoher Bestände, unabgestimmter Abläufe, nicht aktueller Fertigungsunterlagen sowie mangelhafter Informationsflüsse zwischen Planung, Vorbereitung und Ausführung in der Fertigung [1].

  6. Statik starrer Körper in der Ebene

    NASA Astrophysics Data System (ADS)

    Böge, Gert; Böge, Wolfgang

    Die Kraft ist die Ursache einer Bewegungs- oder (und) Formänderung. Man arbeitet in der Statik mit dem Gedankenbild des "starren" Körpers, schließt also die bei jedem realen Körper auftretende Formänderung aus der Betrachtung aus. Jede Kraft lässt sich durch den Vergleich mit der Gewichtskraft eines Wägestücks messen. Eindeutige Kennzeichnung einer Kraft F erfordert drei Bestimmungsstücke (Abb. 9.1):

  7. Evaluation of Sound Therapy Tinnitus Treatments with Concurrent Counseling in Active Duty Military Personnel

    DTIC Science & Technology

    2014-07-04

    Alexandria, Virginia 22314. Orders will be expedited if placed through the librarian or other person designated to request documents from DTIC...an official Department of the Army position, policy, or decision, unless so designated by other official documentation. Citation of trade names in...disorder (Humes, Joellenbeck, and Durch, 2006). Tinnitus is the perception of sound in the absence of an acoustic signal, creating an environment that

  8. Hobeln und Stoßen

    NASA Astrophysics Data System (ADS)

    Böge, Wolfgang

    Im Gegensatz zum Drehen ist die Schnittbewegung bei Maschinen mit hin- und hergehender Bewegung nicht gleichförmig (Hobel-, Stoß- und Räummaschinen). Die mittlere Rücklaufgeschwindigkeit v mr ist meist größer als die mittlere Geschwindigkeit beim Arbeitshub v ma , z. B. beim Antrieb durch die schwingende Kurbelschleife ({v}_{m}\\colon{v}_{ma} etwa 1,4-1,8).

  9. Internet Economics IV

    DTIC Science & Technology

    2004-08-01

    Einwahl ins Internet, eCommerce , Drucken via Internet, Mobile IP, Dateiserver, Unterhaltungsmedien. Nun wollen wir aber ersteinmal die Begrifflichkeiten...verschiedene SLAs angewendet werden. Es gdbe auch die M6glichkeit der Interaktion mit anderen kompatiblen Systemen im eCommerce oder B2B Bereich. Durch genaue...in different areas. The most important of them are: "* The Internet Engineering Task Force; "* The World Wide Web Consortium; "* The Internet Society

  10. Dual Probe Digital Sampling (DPDS) Technique for Rotor Flows--Review of the Development and an Assessment Based on Early Results.

    DTIC Science & Technology

    1982-04-01

    surmount the core memory limitation and provide multiple use under time sharing . An important feature which is typical of computers of this size is the input...distorted, and in other cases appeared to have noise riding on it. (2) The range over which the "Pacer" could follow rotor RPM changes and remain...Untersuchungen Uber den Einfluss der KonizitAt auf die Str~mung durch Turbinengitter im transsonischen Geschwindigkeitsbereich (2. Arbeits- fortschrittsbericht

  11. Das DNA-Puzzle

    NASA Astrophysics Data System (ADS)

    Kirchner, Stefan

    Im Jahre 1953 wurde von James Watson und Francis Crick erstmalig der strukturelle Aufbau der sogenannten DNA (Desoxyribonukleinsäure) beschrieben, welche das Erbgut jedes Lebewesens enthält. Der wesentliche Teil des Erbguts wird dabei durch eine sehr lange Folge der vier Basen Adenin (A), Cytosin (C), Guanin (G) und Thymin (T) codiert. Seit einigen Jahren ist es möglich, die Folge der vier Basen zu einer gegebenen DNA zu bestimmen. Biologen bezeichnen diesen Vorgang als Sequenzierung.

  12. West Europe Report. Science and Technology

    DTIC Science & Technology

    1986-04-28

    Automated (Sha; FRANKFURTER ZEITUNG/BLICK DURCH DIE WIRTSCHAFT, 11 Mar 86) 15 -a - Composition of Italian Robotics Industry (Mariangela...Pattarozzi; MEDIA DUEMILA, No 13, Jan 86).... 17 Olivetti’s Industrial Divisions Profiled (MEDIA DUEMILA, No 13, Jan 86) 20 Briefs Robot Systems to...AUTOMATION COMPOSITION OF ITALIAN ROBOTICS INDUSTRY Turin MEDIA DUEMILA in Italian No 13, Jan 86 pp 13-15 [Article by Mariangela Pattarozzi: "Comau

  13. Johannes Kepler

    NASA Astrophysics Data System (ADS)

    Bialas, Volker

    Johannes Kepler (1571 - 1630) gilt zurecht als einer der bedeutendsten Mathematiker und Astronomen der frühen Neuzeit, doch wurde das Philosophische in seinem Werk bislang kaum in angemessener Weise gewürdigt. Volker Bialas legt eine fundierte und anregende Einführung in Leben, Werk und Weltanschauung Keplers vor und setzt dabei durch die Akzentuierung des philosophisch-ganzheitlichen Denkens bewußt einen Kontrapunkt zum herkömmlichen Kepler-Bild.

  14. Kernkraftwerke

    NASA Astrophysics Data System (ADS)

    Allelein, H. J.

    Die Nutzung der Kernenergie ist untrennbar mit dem Element Uran verknüpft. Da die Umwandlung eines Elements in ein anderes auf chemischem Weg nicht möglich ist, muss das heute vorhandene Uran durch kosmische Prozesse vor Entstehung der Erde entstanden sein. Reines Uran ist ein silberweiß glänzendes, relativ weiches Schwermetall. In der Elementhäufigkeit steht Uran vor Gold, Silber oder Quecksilber.

  15. Uran

    NASA Astrophysics Data System (ADS)

    Bechtel, H.; Bulian, W.; Bungardt, K.; Gürs, K.; Gürs, U.; Helling, W.; Kyri, H.; Laue, H. J.; Mahler, W.; Matting, A.; Meyer, F. R.; Mialki, W.; Ritter, F.; Ruge, J.; Saur, G.; Simon, W.; Strnat, K.; Weber, R.; Weigand, H. H.; Weik, H.; Ziesler, H.; Borchers, Heinz; Schmidt, Ernst

    Bei allen in Tab. 1 angeführten Gewinnungsverfahren [B 23, G 8, W 14] fällt das Uran als Pulver mit einer Teilchengröße von weniger als 0,05 mm an. Die Schmelzflußelektrolyse kann auch zur Nachraffination benutzt werden [A 14]. Hochreines Uran mit besonders niedrigen Gehalten an Eisen, Nickel, Kobalt, Silizium, Bor, Ruthenium, Vanadium, Mangan und Chrom kann durch Zonenschmelzen gewonnen warden [A 11, A 14].

  16. Scattering and Absorption by Thin Metal Wires in Rectangular Waveguide - Chiral Cranks versus Non-Chiral Staples

    DTIC Science & Technology

    2000-09-29

    Theory and Techniques, vol. 45, no. 12, December 1997, pp. 2267-2273. [3] K. F. Lindman , " Uber eine durch ein isotropes System von spiralfbrmigen...mistakenly gave Lindman [3, 4] the credit for the first microwave experiments on artificial chiral materials. Priority, however, belongs by about two... Lindman , and subsequently Tinoco and Freeman [5], were interested in that most familiar of chiral phenomena-the rotation of the polarisation plane of

  17. ENGAGE! A Deliberate Planning Model for the Future Development of Space Power in the Department of Defense

    DTIC Science & Technology

    2010-07-26

    of outer space, our nation expects our Air Force to fully exploit and defend it. Gen John P. Jumper, USAF Chief of Staff (AFDD 2-2, Foreword...in any time zone, or just as easily forward them libraries of information within a matter of seconds. Persistent space-based assets provide advance...Retrieved May 13, 2005, from http://www.aei.org Durch, W. (1988). The abm treaty and western security. Cambridge, MA: Ballinger Publishing. Elhefnawy

  18. An Analysis of Theater Missile Defense Systems.

    DTIC Science & Technology

    2007-11-02

    Ave. Fort Leavenworth, KS, 66027-1352 LTC John M. Rogers University of Kentucky College of Law Lexington, KY, 40506-0048 Naval War College Library ...Both President Clinton and the Chairman of the Joint Chiefs of Staff General John Shailikashvili have stated the country and the military are...1977), 84. 2 1William J. Durch, The ABM Treaty and Western Security (Cambridge: Ballinger Publishing, 1988), 36. 22Ibid., 8. 23Ernest J. Yanarella, The

  19. Failure by Creep Cracking and Creep Fatigue Interaction in Nickel Base Superalloys.

    DTIC Science & Technology

    1984-01-01

    approximatel A normal to the applied tcnsilc stress. thal their average spacing in a grain facet is /, anti that their shaie is 04 % ,, described hs, t,o...intermetallische Grenzflichen zu MetalI -Oxidgrenzflachen umgewandelt werden. Die kinetischen Schritte, die bei Hohlraumnukleation und -wachstum durch...dcpen- Table I. Free energy of formation Standard free energy of formation Temperature AG . range Compound AG ,, (J mole ’) Reference K CO(g) -111.6 x

  20. Could the Outcome of the Genocide in Rwanda be Different with an Operational Planning Cell in the United Nations?

    DTIC Science & Technology

    2012-06-08

    9Prunier, 26. 10Charles Freeman, Crisis in Rwanda. ( Austin , Texas: Raintree Steck-Vaughn, 1999), 16: William J. Durch., UN Peacekeeping, American...reduction for the MDR party. The author Bruce Jones properly describes in his book the impact of this reform: “The MDR had gone from an oligarchic party...Liberia. New York: Zed Books, 2009. Jones, Bruce D. Peacemaking in Rwanda: The Dynamics of Failure. London: Lynne Rienner Publishers, 2001. 42

  1. Non-Destructive Impermeability Testing of Land-Based Sewage Systems (zerstoerungsfreie dichtheitspruefung con grundstuecksentwaesserungsleitungen)

    DTIC Science & Technology

    2001-01-01

    gebers, befestigt durch Messschlauch Schlauchumwicklungen umwickelt I I Miniatur - Gummi - StreifenDruckgeber• -7•1 A A - - --•"Edelstahl - / . Kupplung...Aussage Uiber die Exfiltration in den Boden machen zu konnen ( BEAR , 1979), (RAUCH, 1993). Dabei wird der mit partikularen Schmutzstoffen in Verbindung...Bodenverdinderungen und zur Sanierung von Altlasten (BbodSchG). Bundesgesetzblatt 1 1998, 502 vom 17. Mdirz 1998. BEAR , J. (1979): Hydraulics of Groundwater

  2. Finanzierung des Studiums

    NASA Astrophysics Data System (ADS)

    Domnick, Ivonne

    "Das liebe Geld“ - ein Thema, das Sie durch das ganze Studium begleitet und auch in der Examensphase und bei der späteren Berufswahl eine entscheidende Rolle spielen wird. Naturwissenschaftler und Ingenieure haben auf dem Arbeitsmarkt sicher derzeit die Nase vorn und brauchen sich über ihre berufliche Zukunft nicht so große Gedanken machen. Doch vor der Karriere muss zunächst einmal eine sichere Studienfinanzierung auf die Beine gestellt werden.

  3. Antikollisionssystem PRORETA - Integrierte Lösung für ein unfallvermeidendes Fahrzeug

    NASA Astrophysics Data System (ADS)

    Isermann, Rolf; Bender, Eva; Bruder, Ralph; Darms, Michael; Schorn, Matthias; Stählin, Ulrich; Winner, Hermann

    Dank einer zunehmenden Verbreitung von aktiven und passiven Sicherheitssystemen in Kraftfahrzeugen konnte die Zahl der Verkehrstoten in den letzten Jahren stetig gesenkt werden. Bei der Bearbeitung des Projekts PRORETA wurde mit der Entwicklung eines elektronischen Fahrerassistenzsystems zur Unfallvermeidung das Ziel verfolgt, durch Notbremsen und Notausweichen Unfälle zu vermeiden. Das System wurde an der TU Darmstadt in Kooperation mit der Continental AG entwickelt. Im Folgenden werden die Grundlagen des Systems, Fahrversuche und Ergebnisse einer ergonomischen Studie dargestellt.

  4. Effiziente Verfahren zur Parallelisierung von EMV-Simulationen für den Entwurfsprozess integrierter Schaltungen

    NASA Astrophysics Data System (ADS)

    Barke, M.; Preisner, T.; Mathis, W.

    2009-05-01

    In dieser Arbeit wird mit einer parallelisierten Version des PCG-Verfahrens (preconditioned conjugate gradient method) eine effiziente Technik zur numerischen Lösung großer Gleichungssysteme vorgestellt. Der Anwendungsbereich ist dabei die Simulation numerischer Feldberechnungen (beispielsweise durch die Finite-Elemente-Methode). Es wird ferner auf eine Datenstruktur eingegangen, die für die spezielle Struktur der auftretenden Koeffizientenmatrizen geeignet ist.

  5. Kamera-basierte Erkennung von Geschwindigkeitsbeschränkungen auf deutschen Straen

    NASA Astrophysics Data System (ADS)

    Nienhüser, Dennis; Ziegenmeyer, Marco; Gumpp, Thomas; Scholl, Kay-Ulrich; Zöllner, J. Marius; Dillmann, Rüdiger

    An Fahrerassistenzsysteme im industriellen Einsatz werden hohe Anforderungen bezüglich Zuverlässigkeit und Robustheit gestellt. In dieser Arbeit wird die Kombination robuster Verfahren wie der Hough-Transformation und Support-Vektor-Maschinen zu einem Gesamtsystem zur Erkennung von Geschwindigkeitsbeschränkungen beschrieben. Es setzt eine Farbvideokamera als Sensorik ein. Die Evaluation auf Testdaten bestätigt durch die ermittelte hohe Korrektklassifikationsrate bei gleichzeitig geringer Zahl Fehlalarme die Zuverlässigkeit des Systems.

  6. Kostenüberwachung und Wirtschaftlichkeitsrechnung

    NASA Astrophysics Data System (ADS)

    Bauer, Jürgen

    Die ERP-Produktkalkulation erfolgt auf der Basis des Mengen- und Wertgerüsts der Produktionsprozesse. Sie greift dabei auf die Stammdaten (Materialstamm, Arbeitsplätze, Arbeitspläne, Stücklisten) zu. Basis ist die übliche Industriekalkulation in der Form einer Zuschlagskalkulation, ergänzt durch Platzkostensätze der Maschinen und Arbeitsplätze (siehe Teil ).

  7. Mobile Systems III

    DTIC Science & Technology

    2004-06-01

    werden muss, dass man Kabel nicht einfach quer durch den Raum legen kann. Das fifirt gleich dazu, dass man Unterschiede in der Topologie feststellen kann...Leitung, die im Gegensatz zum Token Ring nicht geschlossen ist. Allerdings wird fiber diese Topologie ein logischer Ring gelegt. 62 Realtime...Abbildung 3.14: Foto vom Roboter im Kaufhaus [10] 3.5 Zusammenfassung 3.5.1 Fazit Im Gegensatz zu Token Ring, das Hardware und Topologie abhdngig ist

  8. Verbesserte Ausbildung für neue Betriebsleiter und -ingenieure - eine wichtige Investition in die Zukunft

    NASA Astrophysics Data System (ADS)

    Franta, Oliver

    Bedingt durch die Globalisierung und die damit einhergehende Verschärfung des Wettbewerbs befinden sich die Produktionsbetriebe der chemischen Industrie in stetigem Wandel. Für Betriebsleiter und Betriebsingenieure werden damit Fähigkeiten wie Kostenmanagement, Sozial- und Organisationskompetenz, Führungsqualifikationen und unternehmerisches Handeln immer wichtiger. Neben den Anforderungsprofilen bei Neueinstellungen ist dies auch bei der Fortbildung zu berücksichtigen. Das Trainingsprogramm der Evonik Degussa wurde daher durch die Konzeption neuer Seminare und die Anpassung bestehender Weiterbildungsmaßnahmen weiterentwickelt. Neben Vorträgen und Fallbeispielen sind ebenfalls die Durchführung von Planspielen sowie das Kennenlernen eines Produktionsbetriebes einer anderen Organisationseinheit enthalten. Ziel ist es vor allem die unternehmerische Orientierung neuer Betriebsleiter und -ingenieure zu fördern, die Innovationsgeschwindigkeit zu erhöhen und durch Kenntnis und Nutzung bereits anderweitig entwickelter Lösungen und Methoden die Produktivität zu steigern. Die Produktionsmeister werden aufgrund der Bedeutung dieser Funktion für die Führung der Mitarbeiter und bei der Umsetzung von Veränderungsprojekten in das Ausbildungsprogramm einbezogen. Der Erfolg des Trainingsprogramms zeigt sich an den Teilnehmerzahlen und den ausgesprochen positiven Rückmeldungen.

  9. Molekulare Methoden zum Nachweis, zur Quantifizierung und zum Monitoring der Mykotoxinbildung lebensmittelrelevanter Pilze

    NASA Astrophysics Data System (ADS)

    Geisen, Rolf

    Schimmelpilze kommen ubiquitär vor und spielen besonders bei pflanzlichen Lebensmitteln und Rohprodukten eine besondere Rolle als Verderbsorganismen. Es wird geschätzt, dass 20-25 % der jährlichen Produktion an pflanzlichen Produkten durch Schimmelpilze verdorben werden (Smith et al., 1994). Viele der lebensmittelrelevanten Schimmelpilze sind zudem in der Lage, Mykotoxine, toxische Sekundärmetabolite, zu bilden, was das Ausmaß des Problems deutlich macht. Die wichtigsten mykotoxinbildenden Spezies gehören zu den Fusarien (Trichothecene, Fumonisine, Zearalenon), Aspergillen (Aflatoxin, Ochratoxin, Cyclopiazonsäure) und Penicillien (Patulin, Ochratoxin). Für viele Mykotoxine, wie die Aflatoxine, Ochratoxin, Fumonisine und Trichothecene sind Grenzwerte erlassen worden, die die Verkehrsfähigkeit betroffener Produkte regeln. Die Einhaltung der Grenzwerte kann sehr genau durch offizielle chemisch-analytische Methoden, wie HPLC, GC-MS etc. kontrolliert werden. Diese analytischen Methoden sind aber für die Anwendung eines HACCP-Ansatzes zur Kontrolle der Mykotoxinbildung nur bedingt geeignet, da sie Endpunktkontrollen darstellen und nur das über eine längere Zeit gebildete Mykotoxin bestimmen. Sie sagen daher nichts über die biologischen Bedingungen zur Zeit der Bildung durch den Pilz aus.

  10. Ein Entscheidungsmodell zur Weitergabe persönlicher Daten im Internet

    NASA Astrophysics Data System (ADS)

    Treiblmaier, Horst

    In den vergangenen zwei Jahrzehnten wandelte sich das Internet von einer Spielwiese für technikbegeisterte Computerspezialisten zu einem vielseitig einsetzbaren weltweiten Netzwerk für Privatpersonen und Unternehmen. Maßgeblichen Anteil daran besaß die rasante Entwicklung des World Wide Web (WWW), das, durch die Möglichkeit multimediale Inhalte zu vermitteln, für einen großen Teil der Bevölkerung industrialisierter Länder zu einem wesentlichen Bestandteil des täglichen Lebens wurde. Dass diese Entwicklung noch lange nicht abgeschlossen ist, zeigt die derzeitige Diskussion zum Thema Web 2.0 bzw. 3.0. Waren es in den letzten Jahren die hohen Umsatzzuwächse im E-Commerce und multimedial gestaltete Webseiten in Kombination mit aufwändigen Applikationen, die für ständig steigende Nutzerzahlen im World Wide Web sorgten, so wird dieser Innovationsschub nunmehr durch eine Vielzahl von Anwendungen fortgesetzt, die sich durch die zunehmende Vernetzung der Nutzer untereinander auszeichnen.

  11. Neue Techniken in der Neurorehabilitation

    NASA Astrophysics Data System (ADS)

    Riener, Robert

    Zentralmotorische Lähmungen durch Schädigungen im Hirn oder Rückenmark stellen weltweit ein großes sozialmedizinisches Problem dar. In Deutschland treten mehr als 250.000 neue Schlaganfälle pro Jahr auf. Zudem leben in Deutschland mehr als 40.000 Menschen mit Querschnittlähmung. Dazu kommen Patienten mit Schädel-Hirn-Trauma, Zerebralparesen, Multipler Sklerose, Parkinson oder Entzündungen und Tumoren des zentralen Nervensystems. Solche zentralmotorische Pathologien können durch manuelle oder automatisierte Bewegungstherapien erfolgreich behandelt werden. Dabei wird durch ein häufiges, repetitives Bewegen von Körpersegmenten die Lern- und Anpassungsfähigkeit des Gehirns und Rückenmarks genutzt. Ist eine Heilung oder Behandlung nicht mehr möglich, so können zahlreiche Techniken dazu beitragen, Bewegungsfunktionen zu unterstützen, so dass die Patienten alltägliche Aktivitäten normal ausführen können und in die Gesellschaft reintegriert werden.

  12. Betriebsführung multimodaler Energiesysteme

    NASA Astrophysics Data System (ADS)

    Mackensen, Reinhard

    Die Transformation des Energiesystems von einer zentral geprägten, unidirektional orientierten und in unterschiedliche Sektoren separierten Struktur hin zu einer umfassenden, multimodalen, dezentralen und flexiblen Erzeuger- und Verbraucherlandschaft findet auf verschiedenen Ebenen statt. Randbedingung bei dieser Umwälzung ist immer die Einhaltung der Teilziele Versorgungssicherheit, Wirtschaftlichkeit und Effizienz. Im Einzelnen schlägt sich diese Transformation in einer Diversifizierung der Akteurslandschaft durch die Mechanismen des Unbundling nieder. Weiterhin finden eine Dezentralisierung der Erzeugerlandschaft und damit eine Substitution von mehrheitlich fossil betriebener Großkraftwerkstechnologie durch eine Vielzahl dezentraler Erzeuger mit zumeist regenerativem Charakter statt. Dieser Wandel hat im Wesentlichen zwei Hauptkonsequenzen. Zum einen ergeben sich durch dezentrale, flächige Verteilung der Erzeuger neue Anforderungen an den Energieaustausch, bspw. aus der Erweiterung der Stromnetze für einen bidirektionalen Energieaustausch, zum anderen werden Abstimmungsmechanismen erforderlich, welche die fluktuierende Einspeisung derart mit dem Verbrauch in Waage hält, dass sowohl elektrische Netzrestriktionen, die Qualität der Versorgung und Aspekte der Energieeffizienz und damit der Wirtschaftlichkeit berücksichtigt werden. Mögliche Antworten auf die mit dieser Betrachtung einhergehenden Fragen liegen in der Konzeption eines multimodalen Energiesystems, also in der Gesamtbetrachtung der Sektoren Strom, Wärme und Verkehr. Dieses Kapitel soll Mechanismen darlegen und Wege aufzeigen, wie eine solche Konzeption gestaltet werden kann und wie solche komplexen Systeme in der Praxis betrieben werden können.

  13. Efficient and Specific Trypsin Digestion of Microgram to Nanogram Quantities of Proteins in Organic-Aqueous Solvent Systems

    SciTech Connect

    Strader, Michael B; Tabb, Dave L; Hervey, IV, William Judson; Pan, Chongle; Hurst, Gregory {Greg} B

    2006-01-01

    Mass spectrometry-based identification of the components of multiprotein complexes often involves solution-phase proteolytic digestion of the complex. The affinity purification of individual protein complexes often yields nanogram to low-microgram amounts of protein, which poses several challenges for enzymatic digestion and protein identification. We tested different solvent systems to optimize trypsin digestions of samples containing limited amounts of protein for subsequent analysis by LC-MS-MS. Data collected from digestion of 10-, 2-, 1-, and 0.2- g portions of a protein standard mixture indicated that an organicaqueous solvent system containing 80% acetonitrile consistently provided the most complete digestion, producing more peptide identifications than the other solvent systems tested. For example, a 1-h digestion in 80% acetonitrile yielded over 52% more peptides than the overnight digestion of 1 g of a protein mixture in purely aqueous buffer. This trend was also observed for peptides from digested ribosomal proteins isolated from Rhodopseudomonas palustris. In addition to improved digestion efficiency, the shorter digestion times possible with the organic solvent also improved trypsin specificity, resulting in smaller numbers of semitryptic peptides than an overnight digestion protocol using an aqueous solvent. The technique was also demonstrated for an affinityisolated protein complex, GroEL. To our knowledge, this report is the first using mass spectrometry data to show a linkage between digestion solvent and trypsin specificity. Mass spectrometry (MS) has become a widely used method for studying proteins, protein complexes, and whole proteomes because of innovations in soft ionization techniques, bioinformatics, and chromatographic separation techniques.1-7 An example of a high-throughput mass spectrometry strategy commonly used for this purpose is a variation of the "shotgun" approach, involving in-solution digestion of a protein complex followed by

  14. Calvin cycle flux, pathway constraints, and substrate oxidation state together determine the H2 biofuel yield in photoheterotrophic bacteria.

    PubMed

    McKinlay, James B; Harwood, Caroline S

    2011-01-01

    Hydrogen gas (H(2)) is a possible future transportation fuel that can be produced by anoxygenic phototrophic bacteria via nitrogenase. The electrons for H(2) are usually derived from organic compounds. Thus, one would expect more H(2) to be produced when anoxygenic phototrophs are supplied with increasingly reduced (electron-rich) organic compounds. However, the H(2) yield does not always differ according to the substrate oxidation state. To understand other factors that influence the H(2) yield, we determined metabolic fluxes in Rhodopseudomonas palustris grown on (13)C-labeled fumarate, succinate, acetate, and butyrate (in order from most oxidized to most reduced). The flux maps revealed that the H(2) yield was influenced by two main factors in addition to substrate oxidation state. The first factor was the route that a substrate took to biosynthetic precursors. For example, succinate took a different route to acetyl-coenzyme A (CoA) than acetate. As a result, R. palustris generated similar amounts of reducing equivalents and similar amounts of H(2) from both succinate and acetate, even though succinate is more oxidized than acetate. The second factor affecting the H(2) yield was the amount of Calvin cycle flux competing for electrons. When nitrogenase was active, electrons were diverted away from the Calvin cycle towards H(2), but to various extents, depending on the substrate. When Calvin cycle flux was blocked, the H(2) yield increased during growth on all substrates. In general, this increase in H(2) yield could be predicted from the initial Calvin cycle flux. Photoheterotrophic bacteria, like Rhodopseudomonas palustris, obtain energy from light and carbon from organic compounds during anaerobic growth. Cells can naturally produce the biofuel H(2) as a way of disposing of excess electrons. Unexpectedly, feeding cells organic compounds with more electrons does not necessarily result in more H(2). Despite repeated observations over the last 40 years, the

  15. [Transition from childhood to adolescence-a qualitative study on experiences of adolescents with type 1 diabetes mellitus and their mothers].

    PubMed

    Gabele, Angela; Budde, Jörg; Spichiger, Elisabeth

    2015-04-01

    Hintergrund: In Deutschland erkranken jährlich etwa 2 200 Kinder unter 14 Jahren an Typ 1 Diabetes mellitus (T1DM). Bei Kleinkindern führen die Eltern das Diabetes-Management durch, später übernehmen Kinder einzelne Aufgaben. Während der Transition von der Kindheit zur Adoleszenz, im Alter von 8 – 13 Jahren, lernen Kinder selbstständiger zu werden. Kinder mit T1DM bewältigen eine weitere Transition im Diabetes-Management. Bislang fokussierte die Forschung jedoch auf die Transition Adoleszenz – Volljährigkeit. Fragestellung: Mit der Studie wurden das Erleben von Jugendlichen mit T1DM und ihrer Mütter während der Transition von der Kindheit zur Adoleszenz und die Bedeutung von Selbstständigkeit exploriert. Methode: Die interpretierende phänomenologische Studie fand in zwei süddeutschen Diabetes-Ambulanzen statt. Sechs Jugendliche und ihre Mütter nahmen an Interviews mit offenen Fragen teil. Daten wurden mittels Fall- und thematischer Analyse ausgewertet. Ergebnisse: Jugendliche erlebten die Übernahme der Diabetes-Aufgaben für immer längere Zeiträume und die damit verbundene größere Selbstständigkeit als befreiend. Mütter lernten ihren Kindern dies zuzutrauen. Ihre größte Sorge blieb eine mögliche Hypoglykämie. Familienmitglieder und Lehrer(innen) waren unterschiedlich in das Diabetes-Management involviert. Die kontinuierliche Betreuung durch dieselben Ärzte/Ärztinnen der Ambulanzen wurde als unterstützend erlebt. Schlussfolgerung: Eine kontinuierliche Betreuung durch dieselben Fachpersonen kann sich positiv auf die Transition Kindheit – Adoleszenz von Kindern mit T1DM auswirken.

  16. "May I help you?" - Evaluation of the new student service at the reception desk during the clinical courses at the Department of Operative Dentistry and Periodontology as a part of a longitudinal curriculum of social and communicative competences for dental students.

    PubMed

    Lichtenstein, Nora; Ensmann, Isabelle; Haak, Rainer; Hallal, Houda; Kupke, Jana; Matthes, Jan; Noack, Michael; Wicht, Michael; Stosch, Christoph

    2015-01-01

    Zielsetzung: An der Universität zu Köln wird seit 2009 auf der Basis der Empfehlungen der Association for Dental Education in Europe (ADEE) ein longitudinales Curriculum zur Vermittlung von sozialen und kommunikativen Kompetenzen in der Zahnmedizin (LSK-Dent) entwickelt. Im Rahmen dieses Curriculums wurde überlegt, einen Rezeptionsdienst in den Behandlungskursen der Poliklinik für Zahnerhaltung und Parodontologie zu entwickeln, welcher die organisatorische und administrative Abwicklung der Patienten durch die Studierenden beinhaltet. Durch ihn sollen die Studierenden Einblicke in Praxisabläufe erhalten und er soll als Lernwelt für soziale und kommunikative Kompetenzen fungieren. Dieser Beitrag stellt sowohl das LSK-Dent Projekt als auch die Umsetzung des Rezeptionsdienstes vor und es werden erste Evaluationsergebnisse berichtet. Methodik: Es wurden Patienten (n=575) und Studierende (n=53) mittels Fragebögen befragt. Zusätzlich wurden vier halbstandardisierte Interviews mit Studierenden geführt Ergebnisse: Der Rezeptionsdienst konnte erfolgreich implementiert werden und wird von Patienten und Studierenden gut angenommen. Es zeigen sich erste Hinweise, dass der Rezeptionsdienst von den Studierenden als eine Lernwelt zum Trainieren von sozialen und kommunikativen Fähigkeiten wahrgenommen wird und dass die Studierenden durch ihn einen Einblick in Praxisabläufe erhalten. Schlussfolgerung: Der Rezeptionsdienst stellt eine innovative Ergänzung der bisherigen Behandlungskurse dar und zeigt beispielhaft die Umdeutung bestehender Realitäten in modellierte Erfahrungs- und Lernwelten für Studierende. Inwiefern reflexive Elemente – konzeptionell eingebracht – den subjektiv wahrgenommenen Mehrwert erhöhen können, muss in weiteren Untersuchungen geklärt werden.

  17. Molekülbillard

    NASA Astrophysics Data System (ADS)

    Weiser, Martin

    Die Entwicklung moderner Medikamente (siehe Abbildung 1) zielt auf das Design von hochspezifischen Wirkstoffen, um Nebenwirkungen so weit wie möglich auszuschließen. Da biochemische Reaktionen, z. B. die Blockade eines Rezeptors durch ein Wirkstoffmolekül, zumeist nach dem Schlüssel-Schloss-Prinzip funktionieren, ist die Gestalt von Molekülen entscheidend für die Wirksamkeit. Biochemische Tests oder gar klinische Studien sind aufwändig und teuer, daher werden zunehmend mathematische Simulationsverfahren zur Berechnung der Gestalt von Molekülen verwendet.

  18. Zum Glück gibt es Garantie!

    NASA Astrophysics Data System (ADS)

    Mehrmann, Volker

    Die numerische Lösung von Gleichungssystemen ist eine zentrale Aufgabe bei der Untersuchung fast jeden wissenschaftlichen Problems. Die Beschreibung physikalischer, chemischer oder biologischer Prozesse erfolgt im Wesentlichen immer durch Systeme von Gleichungen. Diese können aus Differentialgleichungen oder auch algebraischen Gleichungen bestehen. Lösungsverfahren dieser Systeme führen jedoch meist auf das Lösen von sehr großen linearen Gleichungssystemen. Daher ist es notwendig Methoden zu entwickeln um diese linearen Gleichungssysteme effizient zu lösen.

  19. Mittelwert- und Arbeitstaktsynchrone Simulation von Dieselmotoren

    NASA Astrophysics Data System (ADS)

    Zahn, Sebastian

    Getrieben durch die immer restriktiveren Anforderungen an das Emissions- und Verbrauchsverhalten moderner Verbrennungsmotoren steigt die Komplexität von Motormanagementsystemen mit jeder Modellgeneration an. Damit geht nicht nur eine Zunahme des Softwareumfangs von Steuergeräten sondern zugleich ein deutlicher Anstieg des Applikations-, Vermessungs- und Testaufwandes einher. Zur Effizienzsteigerung des Software- und Funktionsentwicklungsprozesses haben sich daher in der Automobilindustrie sowie in Forschungsinstituten verschiedene modell- und simulationsbasierte Methoden wie die Model-in-the-Loop (MiL) Simulation, die Software-in-the-Loop (SiL) Simulation, das Rapid Control Prototyping (RCP) sowie die Hardware-in-the-Loop (HiL) Simulation etabliert.

  20. Grundlagenuntersuchungen

    NASA Astrophysics Data System (ADS)

    Murrenhoff, Hubertus

    Die Analyse und Optimierung der tribologischen Systeme hinsichtlich des Reibungs- und Verschleißverhaltens (Kap. 2) erfordert eine aussagekräftige Mess- und Prüftechnik. Die tribologische Prüftechnik kann nach [Czic82] in Prüfmethoden, -systeme und Analysemethoden eingeteilt werden. Die tribologische Prüftechnik kennzeichnet sich durch einen hohen technischen Stand aus, die unmittelbare Übertragbarkeit der Messergebnisse auf andere Prüfsysteme und auf reale Bauteile und Konstruktionen ist jedoch unsicher. Die Ergebnisse der Prüfungen sollten daher auf den untersuchten Verschleißfall bezogen werden.

  1. Regelungsstrategie für zweibeiniges elastisches Laufen mittels "Virtual Model Control``

    NASA Astrophysics Data System (ADS)

    Kerscher, T.; Göller, M.; Zöllner, J. M.; Dillmann, R.

    Ziel dieses Vorhabens ist die technische Umsetzung des "elastischen Laufens“ durch die Realisierung biomechanisch motivierter Regelungsstrategien. Als dafür nötigen elastischen Antrieb wird ein künstlicher Muskel nach dem McKibben-Prinzip verwendet. Dieser Muskel zeigt trotz einiger Nachteile sehr ähnliches statisches und dynamisches Verhalten wie der biologische Muskel und hat sich daher für dieses Vorhaben als idealer Antrieb herausgestellt. Mit Hilfe des "Virtual Model Control“ wird eine Regelung für elastisches Gehen entworfen, welche direkt und indirekt die Eigenschaften der Muskeln für eine flüssige, energieeffiziente Bewegung verwendet.

  2. Hören - Psychoakustik - Audiologie

    NASA Astrophysics Data System (ADS)

    Ellermeier, Wolfgang; Hellbrück, Jürgen

    Anatomisch ist das Ohr des Menschen in äußeres Ohr, Mittelohr und Innenohr unterteilt. Zum äußeren Ohr gehören Ohrmuschel (Pinna) und äußerer Gehörgang (Meatus acusticus externus). Die Ohrmuschel besteht - mit Ausnahme des Ohrläppchens - aus Knorpeln. Sie enthält auch Muskelgewebe, das beim Menschen nur noch rudimentär ausgebildet ist und nicht mehr wie bei vielen Tieren durch Bewegung der Ohrmuschel der Schallortung dient.

  3. Funkmesstechnik

    NASA Astrophysics Data System (ADS)

    Plaßmann, Wilfried

    Ein Hauptgebiet der Funkmesstechnik ist durch den Begriff RADAR (radio detection and ranging gekennzeichnet. Bei diesem Verfahren werden impulsförmige elektromagnetische Wellen von einer Antenne ausgesendet und an Körpern oder Stoffverteilungen (Wolken) reflektiert. Die Sendeantenne wird auf Empfang umgeschaltet, und anhand des Echos sind Rückschlüsse auf die Lage und die Beschaffenheit der Körper oder der Stoffverteilungen möglich. Angewendet wird die Radartechnik bei der Kontrolle und der Sicherung des Land-, Wasser- und Flugverkehrs, in der Meteorologie zur Wetterprognose, in der Astrologie und im militärischen Bereich.

  4. Energieeffizienz im Verkehr

    NASA Astrophysics Data System (ADS)

    Helms, Hinrich; Lambrecht, Udo; Hanusch, Jan

    Mobilität - also Beweglichkeit - kennzeichnet unsere Gesellschaft heute mehr als je zuvor. So können und müssen viele individuelle Bedürfnisse nicht mehr direkt am Wohnort, sondern an anderen Orten erfüllt werden. Mobilität kann in diesem Kontext auch definiert werden als " die Möglichkeit, durch Ortsveränderung Interessen realisieren zu können.“ (SRU 2005). Oft führt eine hohe Mobilität auch zu hohem Verkehrsaufkommen, wobei Verkehr dabei als tatsächliche Ortsveränderung verstanden wird (realisierte Mobilität).

  5. Geometrie verstehen: statisch - kinematisch

    NASA Astrophysics Data System (ADS)

    Kroll, Ekkehard

    Dem Allgemeinen steht begrifflich das Besondere gegenüber. In diesem Sinne sind allgemeine Überlegungen zum Verstehen von Mathematik zu ergänzen durch Untersuchungen hinsichtlich des Verstehens der einzelnen mathematischen Disziplinen, insbesondere der Geometrie. Hier haben viele Schülerinnen und Schüler Probleme. Diese rühren hauptsächlich daher, dass eine fertige geometrische Konstruktion in ihrer statischen Präsentation auf Papier nicht mehr die einzelnen Konstruktionsschritte erkennen lässt; zum Nachvollzug müssen sie daher ergänzend in einer Konstruktionsbeschreibung festgehalten werden.

  6. Precipitation in Powder Metallurgy, Nickel Base Superalloys: Review of Modeling Approach and Formulation of Engineering (Postprint)

    DTIC Science & Technology

    2016-12-01

    increase of the average precipitate size was interpreted in terms of the classical Lifshitz-Slyozov- Wagner (LSW) theory modified to treat the coarsening of...the induction and steady-state effects. Adv Colloid Interface Sci 13:205–318 11. Haasen P, Gerold V, Wagner R, Ashby MF (1984) Decomposition of alloys...Solids 19:35–51 16. Wagner C (1961) Theorie der alterung von niederschlägen durch umlösen (Ostwald‐reifung). Zeit Elektrochem 65: 581–591 Semiatin et al

  7. Erfahrungen im Aufbau des IT Service Desks der Technischen Universität München

    NASA Astrophysics Data System (ADS)

    Vellguth, Karmela

    Durch das Projekt IntegraTUM und die darin eingebettete Einrichtung eines IT Service Desks mit 1st, 2nd und 3rd Level Support gelang eine an ITIL orientierte Neuausrichtung der internen IT-Dienstleistungen. Die vormals existierende Struktur mit einer Vielzahl an Ansprechpartnern bei auftretenden IT-Problemen wurde aufgelöst. Die Nutzer haben nun eine Anlaufstelle erhalten, die sich für die Beantwortung aller Incidents in kürzester Zeit und mit qualitativ hohem Niveau zuständig fühlt.

  8. Definition von Datenarten zur konsistenten Kommunikation im Unternehmen

    NASA Astrophysics Data System (ADS)

    Piro, Andrea; Gebauer, Marcus

    Probleme in der Informationsqualität (IQ) treten in den unterschiedlichsten Bereichen eines Unternehmens auf und werden durch die unterschiedlichsten Bereiche verursacht. Daher ist es um so wichtiger, diese Probleme klar und eindeutig kommunizieren zu können. Insbesondere wenn Kollegen fachübergreifend IQ-Probleme beheben wollen, kann dies schwierig sein. Erst wenn klar ist, worüber geredet wird, und häufig sind dies Datenfelder und ihr Inhalt, kann das Problem eindeutig beschrieben und gelöst werden.

  9. Schichtübergreifende Früherkennung von Verbindungsausfällen in drahtlosen Mesh-Netzwerken

    NASA Astrophysics Data System (ADS)

    Lindhorst, Timo

    Drahtlose Mesh-Netzwerke (WMNs) bilden aufgrund ihrer Selbstorganisation ein flexibles Kommunikationssystem. Bei der Erkennung einzelner Verbindungsausfälle, die bei der Integration mobiler Teilnehmer unvermeidbar sind, ist bei aktuellen Routingprotokollen die Kommunikation jedoch für mehrere Sekunden unterbrochen. In dieser Arbeit wird gezeigt, wie durch Nutzung von Informationen aus der MAC-Schicht ein Ausfall frühzeitig erkannt und dadurch die Anzahl der Paketverluste von mehreren Hundert auf maximal vier reduziert werden kann. Hierdurch wird die Zuverlässigkeit und Verfügbarkeit von WMNs erhöht und ihr Einsatz für Echtzeit-Anwendungen ermöglicht.

  10. Definition von Datenarten zur konsistenten Kommunikation im Unternehmen

    NASA Astrophysics Data System (ADS)

    Piro, Andrea; Gebauer, Marcus

    Probleme in der Informationsqualität (IQ) treten in den unterschiedlichsten Bereichen eines Unternehmens auf und werden durch die unterschiedlichsten Bereiche verursacht. Daher ist es um so wichtiger, diese Probleme klar und eindeutig kommunizieren zu können. Insbesondere wenn Kollegen fachübergreifend IQProbleme beheben wollen, kann dies schwierig sein. Erst wenn klar ist, worüber geredet wird, und häufig sind dies Datenfelder und ihr Inhalt, kann das Problem eindeutig beschrieben und gelöst werden.

  11. Physikgeschichte Die Anfänge des Physik-Nobelpreises

    NASA Astrophysics Data System (ADS)

    Jacobi, Manfred

    2003-09-01

    Durch Absorption von zwei Laserstrahlen mit unterschiedlichen Wellenlängen können in Halbleitern makroskopische Ströme erzeugt werden. Die Ausbreitungsrichtung der Elektronen und insbesondere die Ausrichtung ihrer Spins lassen sich über die relative Phase der beiden Laserfelder kohärent kontrollieren, wie kürzlich zwei Gruppen an den Universitäten von Marburg und Iowa demonstrierten [1, 2]. Genutzt wird bei diesem Experiment der Effekt der Quanteninterferenz zur Erzeugung von elektrischen Spinströmen.

  12. Festkörperphysik Optisch erzeugte Spinströme

    NASA Astrophysics Data System (ADS)

    Hübner, Jens

    2003-09-01

    Durch Absorption von zwei Laserstrahlen mit unterschiedlichen Wellenlängen können in Halbleitern makroskopische Ströme erzeugt werden. Die Ausbreitungsrichtung der Elektronen und insbesondere die Ausrichtung ihrer Spins lassen sich über die relative Phase der beiden Laserfelder kohärent kontrollieren, wie kürzlich zwei Gruppen an den Universitäten von Marburg und Iowa demonstrierten [1, 2]. Genutzt wird bei diesem Experiment der Effekt der Quanteninterferenz zur Erzeugung von elektrischen Spinströmen.

  13. Unfälle mit Zweiradfahrzeugen

    NASA Astrophysics Data System (ADS)

    Tschirschwitz, Christian

    Auf einer außerörtlichen Bundesstraße kam es in einem Baustellenbereich zum frontalen Anprall eines Pkw Ford Fiesta an die rechte Flanke eines Fahrrads, welches durch einen Fußgänger von links nach rechts, bezüglich der Fahrtrichtung des Pkw, geschoben wurde. Das Fahrrad und der Fußgänger wurden auf den Vorbau des Pkw aufgeladen und etwa 15m weit geworfen. Der Fußgänger verstarb noch an der Unfallstelle.

  14. Komplexität der Geographie

    NASA Astrophysics Data System (ADS)

    Diekert, Volker; Hertrampf, Ulrich

    Das allgemein als Prototyp eines PSPACE-vollständigen Spiels gesehene Geographiespiel wird bezüglich seiner Komplexität genauer untersucht. Das Interesse der theoretischen Informatik an diesem Spiel wurde sehr durch die Darstellung in dem Lehrbuch von Papadimitriou [Pap94] gefördert. Allerdings bestimmt dieses Lehrbuch nicht die Komplexität des Standardspiels sondern verwendet eine Verallgemeinerung. Die Aussage in dem Lehrbuch bleibt damit etwas unbefriedigend und hinter den Möglichkeiten. Wir zeigen hier, dass die komplexitätstheoretische Charakterisierung schon für die Standardvariante des Spiels gilt.

  15. Was leistet ein Sportler? Kraft, Leistung und Energie im Muskel

    NASA Astrophysics Data System (ADS)

    Thaller, Sigrid; Mathelitsch, Leopold

    2006-01-01

    Der Leistungsbegriff ist im Sport weiter gefasst als in der Physik. In beiden Fällen liegt der Fokus jedoch auf einer pro Zeiteinheit erfolgten Energieumsetzung. Allerdings gibt die rein physikalische Leistung nicht immer Auskunft über den Energieumsatz der Muskeln. Die Muskelkraft hängt von der Kontraktionsgeschwindigkeit des Muskels ab. Ein Muskel verhält sich also anders als eine Feder. Für den Hochleistungssport müssen die Energieumsätze der Muskeln durch spezielle Trainings- und Nahrungsprogramme optimiert werden.

  16. Emulsified Zero-Valent Nano-Scale Iron Treatment of Chlorinated Solvent DNAPL Source Areas

    DTIC Science & Technology

    2010-04-01

    Integral Mass Flux Estimation and Reactive Transport Modelling in Heterogeneous Porous Media. Ph.D. Thesis . The University of Tübingen, Tübingen, Germany...1318. Schwarz, R. 2001. Grundwasser-Gefährdungs-abschätzung durch Emmissions- und Immissions-messungen an Deponien und Altlasten. Ph.D. Thesis ...34 ~· \\!L \\ •’ H )? (\\ " lit •• (<I •·’ ··’ (I I’ 11ə\\, ,, ,, ,, •• ,, ’>’·l •’ ,, •’ •• (I •’ Efl ~cts ot\\ Oroundwat~r Srunrles" by MJ Biu<:duna ct nl

  17. Proceedings of the Seventh Joint Magnetism and Magnetic Materials-Intermag Conference 6-9 January 1998 San Francisco, California Volume 83, Number 11, Part 2.

    DTIC Science & Technology

    2007-11-02

    electromagnetischen Schwebefahzeugs durch die Simulation," VDI- Berichte, Nr .510, S.223, March 1984. 11T. Ueyama, K. Shinkura, and R. Ueda, IEEE...0.20 3 1 0.15 \\ 󈧏 *,/ ■*’ 20 K 0.10 0.05 r\\ nr \\ ’^f Ho"(T) 0.0 0.5 1.0 1.5 2.0 "’Electronic mail: havela@apollo.karlov.mff.cuni.cz FIG. 1...were determined on the M-H hysteresis loops measured by the vibrating sample magnetometer (VSM). The relative permeability / nr was measured by

  18. Hinderniserkennung und -verfolgung mit einer PMD-kamera im automobil

    NASA Astrophysics Data System (ADS)

    Schamm, Thomas; Vacek, Stefan; Natroshvilli, Koba; Marius Zöllner, J.; Dillmann, Rüdiger

    Die Detektion von Hindernissen vor dem Automobil ist eine Hauptanforderung an moderne Fahrerassistenzsysteme (FAS). In dieser Arbeit wird ein System vorgestellt, das mit Hilfe einer PMDKamera (Photomischdetektor) Hindernisse auf der Fahrspur erkennt und deren relevante Parameter bestimmt. Durch die PMD-Kamera werden zunächst 3D-Tiefenbilder der Fahrzeugumwelt generiert. Nach einem initialen Filterprozess werden im Tiefenbild mit Hilfe eines Bereichswachstumsverfahrens Hindernisse gesucht. Zur Stabilisierung des Verfahrens und zur Parameterberechnung wird ein Kaiman Filter eingesetzt. Das Ergebnis ist eine Liste aller Hindernisse im Fahrbereich des Automobils.

  19. Nutzergerechte Entwicklung der Mensch-Maschine-Interaktion von Fahrerassistenzsystemen

    NASA Astrophysics Data System (ADS)

    König, Winfried

    Durch langjährige Forschungen bei Kfz-Herstellern, Zulieferfirmen und an Hochschulen sind umfangreiche, aber dennoch lückenhafte Erkenntnisse über das Zusammenspiel zwischen FAS und Nutzer gewonnen worden. In deutschen und internationalen Projekten wie z. B. PROMETHEUS, DRIVE, MOTIV, INVENT, RESPONSE und AKTIV haben sich Kfz-Hersteller, Zulieferfirmen, Hochschulen und weitere staatliche und private Forschungseinrichtungen zusammengefunden, um die vorwettbewerbliche Forschung für derartige Systeme voranzutreiben. Im folgenden Kapitel sollen einige der gewonnenen Kenntnisse dargelegt werden, um die Entwicklung des HMI von FAS zu erleichtern.

  20. Smartphone application of primary care guidelines used in education of medical students.

    PubMed

    Waldmann, Uta-Maria; Weckbecker, Klaus

    2013-01-01

    Hintergrund und Fragestellung: Die Leitlinien der Deutschen Gesellschaft für Allgemeinmedizin (DEGAM) zu häufigen und wichtigen Beratungsanlässen in der Hausarztpraxis sind ein zentraler Inhalt der Lehre im Fach Allgemeinmedizin. Durch die Autoren wurden sie als App für Mobiltelefone aufbereitet und stehen somit nun Hausärzten und Studierenden jederzeit zur Verfügung. Die vorliegende Studie untersucht die Fragestellung: Wie bewerten Studierende den Nutzen dieser Anwendung für ihren Lernprozess im Fach Allgemeinmedizin?Methodik: Die Kurzversionen der 15 DEGAM-Leitlinien wurden als (Smartphone-Betriebssystem-unabhängige) Web-App mit Möglichkeit der Offline-Nutzung umgesetzt und Studierenden in Kurs, Blockpraktikum, Wahlfächern und PJ (Praktisches Jahr) Allgemeinmedizin angeboten. Die Evaluation erfolgte durch eine strukturierte Befragung über die Feedbackfunktion der Moodle-Lernplattform www.elearning-allgemeinmedizin.de mit Likertskalen und Freitextkommentaren.Ergebnisse: Der Evaluations-Rücklauf kam von 14 (25%) der 56 studentischen TesterInnen aus dem Kurs Allgemeinmedizin (9), dem Blockpraktikum (1), dem PJ (1) und Wahlfächern (4). Die App selbst sehen die Studierenden als Mehrwert zur Print/PDF-Version. Sie nutzen sie häufig und erfolgreich in Nischenzeiten und vor/während/nach Lehrveranstaltungen. Neben allgemeinem Interesse / Kennenlernen der Leitlinien und Lernen wird sie zum Nachschlagen konkreter (theoretischer) Fragestellungen eingesetzt, weniger im Zusammenhang mit Patientenkontakten. Interesse und Kenntnis der Leitlinien wird durch die App gefördert, insgesamt ist die Anwendung für die Bedürfnisse dieser Usergruppe gut geeignet.Diskussion: Die Leitlinien-App wurde von Studierenden sehr positiv bewertet: Als moderne Form, ihnen die Leitlinien näher zu bringen und ihre Kenntnisse zu erweitern, gerade auch durch den flexiblen Einsatz in Nischenzeiten und das attraktive Medium Smartphone. Letzteres verhindert aber auch eine verbindliche

  1. Grußwort

    NASA Astrophysics Data System (ADS)

    Jähnichen, Stefan

    Vielen Dank für die Einladung zu dieser Konferenz und vielen Dank an Dr. Udo Bub. Meine ersten Grüße richte ich allerdings zunächst als Aufsichtsrat der EICT GmbH an Sie, da ich mich über die Entwicklung der EICT GmbH und über diese von der EICT organisierte Veranstaltung besonders freue. Sie bildet eine Basis für die weitere Kommunikation über ein so wichtiges Thema wie Sicherheit und für die notwendige Beachtung durch Politik und Ministerien.

  2. Einleitung

    NASA Astrophysics Data System (ADS)

    Broy, Manfred

    Seit der Erfindung programmierbarer Rechner durch Konrad Zuse vor kaum 70 Jahren haben programmierbare Informationsverarbeitungssysteme einen atemberaubenden Aufschwung genommen. Das Mooresche Gesetz mit seiner exponentiellen Steigerung der Leistungsfähigkeit der Hardware in Hinblick auf Rechen-, Speicher- und übertragungsleistung liefert dafür die technische Grundlage. Die Flexibilität programmierbarer Software ergänzt sich dazu ideal - schafft sie doch die Möglichkeiten und die Voraussetzungen dafür, dass sich diese Systeme in praktisch allen Anwendungsfeldern einsetzen lassen.

  3. Grundlagen und Vollzug der amtlichen Lebensmittelkontrolle in der Schweiz

    NASA Astrophysics Data System (ADS)

    Hübner, Philipp; Spinner, Christoph

    In der Schweiz wird die Mehrheit der hoheitlichen Aufgaben von den 26 Kantonen, die zusammen die schweizerische Eidgenossenschaft bilden, autonom vollzogen. So liegt zum Beispiel die Kompetenz in den Bereichen Steuern, Gesundheit, Schulen oder Polizei grundsätzlich bei den Kantonen. Im Gegensatz dazu ist die Lebensmittelgesetzgebung national durch eidgenössische Erlasse harmonisiert. Die Vollzugsaufgaben liegen aber auch in diesem Bereich, abgesehen vom Vollzug an der Grenze und von einer nationalen Vollzugsaufsicht und Weisungsberechtigung, in kantonaler Kompetenz. Die Kantone können anhand kantonaler Erlasse das Bundesrecht präzisieren - insbesondere die organisatorischen Aspekte - und Regelungen im nicht harmonisierten Bereich treffen.

  4. Ökophysik: Plaudereien über das Leben auf dem Land, im Wasser und in der Luft

    NASA Astrophysics Data System (ADS)

    Nachtigall, W.

    Prof. em. Dr. rer. nat. Werner Nachtigall, geb. 1934, war als Zoophysiologe und Biophysiker Leiter des Zoologischen Instituts der Universität des Saarlandes in Saarbrücken. In Forschung und Ausbildung hat er sich insbesondere mit Aspekten der Technischen Biologie und Bionik befasst und mit seinen Forschergruppen viele Basisdaten insbesondere zur Ökologie, Physiologie und Physik des Fliegens und Schwimmens aber auch zur Stabilität beispielsweise der Gräser erarbeitet. Lebewesen überraschen immer wieder durch ihre "Biodiversität", ihre hochspezifischen Ausgestaltungen und Anpassungen.

  5. Das Märchen vom Zauberer im weißen Kittel: Mythen um berühmte Experimente und Experimentatoren

    NASA Astrophysics Data System (ADS)

    Hentschel, Klaus

    2003-09-01

    Um berühmte Experimentatoren und Experimente ranken sich ebenso Mythen wie um geniale Theoretiker. Sie sind in populärwissenschaftlichen Büchern, Lehrbüchern und sogar in wissenschaftshistorischen Texten verbreitet. Die durch die Aufklärung etablierte Kultur des eleganten Schauexperiments vermittelt ein schiefes Bild vom mühsamen Weg vieler Experimentatoren zum dargestellten Ergebnis. Auch der Mythos des einsamen, genialen Experimentators ohne Helfer widerspricht dem historischen Befund. Gleiches gilt für das experimentum crucis, das eine Theorie als entscheidendes Experiment belegen soll. Die historische Forschung zeigt, dass es eine lange, eigenständige Tradition der experimentellen und instrumentellen Arbeit gibt.

  6. Level-Set-Segmentierung von Rattenhirn MRTs

    NASA Astrophysics Data System (ADS)

    Eiben, Björn; Kunz, Dietmar; Pietrzyk, Uwe; Palm, Christoph

    In dieser Arbeit wird die Segmentierung von Gehirngewebe aus Kopfaufnahmen von Ratten mittels Level-Set-Methoden vorgeschlagen. Dazu wird ein zweidimensionaler, kontrastbasierter Ansatz zu einem dreidimensionalen, lokal an die Bildintensität adaptierten Segmentierer erweitert. Es wird gezeigt, dass mit diesem echten 3D-Ansatz die lokalen Bildstrukturen besser berücksichtigt werden können. Insbesondere Magnet-Resonanz-Tomographien (MRTs) mit globalen Helligkeitsgradienten, beispielsweise bedingt durch Oberfiächenspulen, können auf diese Weise zuverlässiger und ohne weitere Vorverarbeitungsschritte segmentiert werden. Die Leistungsfähigkeit des Algorithmus wird experimentell an Hand dreier Rattenhirn-MRTs demonstriert.

  7. Sandsturm kontra Wassersturm: Physik im Alltag

    NASA Astrophysics Data System (ADS)

    Müller, Andreas

    2006-07-01

    Sandstürme ereignen sich oft, Wasserstürme hingegen so gut wie nie. Eine Abschätzung zeigt, dass man beim Herauslösen eines Wassertropfens beispielsweise aus dem Meer eine sehr große Kraft benötigt und sehr viel Arbeit verrichten muss. Das scheint die Erklärung zu sein. Führt man eine entsprechende Energiebetrachtung durch, so könnte es durchaus Wasserstürme geben. Diese Überlegung ist zwar mathematisch richtig, aber unvollständig.

  8. Unfälle mit Zweiradfahrzeugen

    NASA Astrophysics Data System (ADS)

    Tschirschwitz, Christian

    Auf einer außerörtlichen Bundesstraße kam es in einem Baustellenbereich zum frontalen Anprall eines Pkw Ford Fiesta an die rechte Flanke eines Fahrrads, welches durch einen Fußgänger von links nach rechts, bezüglich der Fahrtrichtung des Pkw, geschoben wurde. Das Fahrrad und der Fußgänger wurden auf den Vorbau des Pkw aufgeladen und etwa 15m weit geworfen. Der Fußgänger verstarb noch an der Unfallstelle.

  9. Reflexionseigenschaften von Windenergieanlagen im Funkfeld von Funknavigations- und Radarsystemen

    NASA Astrophysics Data System (ADS)

    Sandmann, S.; Divanbeigi, S.; Garbe, H.

    2015-11-01

    Die hier behandelte Untersuchung befasst sich mit den Störungen des elektrischen Feldes einer Doppler Very High Frequency Omnidirectional Radio Range Navigationsanlage (DVOR) in der Gegenwart von Windenergieanlagen (WEA). Hierfür wird die Feldstärke auf 25 konzentrischen Kreisbahnen, sog. Orbit Flights verschiedener Höhen und mit verschiedenen Radien rund um die DVOR-Anlage numerisch simuliert. Insbesondere werden die Einflüsse diverser Parameter der WEA wie deren Anzahl, Position, Rotorwinkel, Turmhöhe und Rotordurchmesser auf die Feldverteilung herausgestellt, sowie die Anwendbarkeit der Simulationsmethode Physical Optics (PO) durch Vergleich der Simulationsergebnisse mit denen der Multi Level Fast Multipol Method (MLFMM) untersucht.

  10. Quantenwelt im Nanozylinder: Elektronische Eigenschaften von Kohlenstoff-Nanoröhrchen

    NASA Astrophysics Data System (ADS)

    Strunk, Christoph

    2005-07-01

    Kohlenstoff-Nanoröhren sind einzelne oder mehrfach ineinander gesteckte molekulare Hohlzylinder. In ihnen bilden Kohlenstoffatome ein Graphit ähnliches Kristallgitter. Diese Fullerene zeichnen sich durch eine außerordentlich hohe Elastizität und Zugfestigkeit aus. In ihren elektronischen Eigenschaften verhalten sie sich entweder wie Halbleiter oder wie metallische Leiter. Aus halbleitenden Nanoröhren konnten bereits winzige Feldeffekttransistoren hergestellt werden, ein erster Schritt hin zu einer molekularen Elektronik. Die Grundlagenforscher interessiert vor allem das Verhalten metallischer Nanoröhren bei tiefen Temperaturen. An ihren elektronischen Systemen lassen sich zum Beispiel Quanteninterferenzphänomene oder Elektron-Elektron-Wechselwirkungen untersuchen.

  11. Structure of a Specialized Acyl Carrier Protein Essential for Lipid A Biosynthesis with Very Long-chain Fatty Acids in Open and Closed Conformations

    SciTech Connect

    Ramelot, Theresa A.; Rossi, Paolo M.; Forouhar, Farhad; Lee, Hsiau-Wei; Yang, Yunhuang; Ni, Shuisong; Unser, Sarah; Lew, Scott; Seetharaman, Jayaraman; Xiao, Rong; Acton, Thomas; Everett, John K.; Prestegard, James H.; Hunt, John F.; Montelione, Gaetano; Kennedy, Michael A.

    2012-09-18

    The solution nuclear magnetic resonance (NMR) structures and backbone (15)N dynamics of the specialized acyl carrier protein (ACP), RpAcpXL, from Rhodopseudomonas palustris, in both the apo form and holo form modified by covalent attachment of 4'-phosphopantetheine at S37, are virtually identical, monomeric, and correspond to the closed conformation. The structures have an extra α-helix compared to the archetypical ACP from Escherichia coli, which has four helices, resulting in a larger opening to the hydrophobic cavity. Chemical shift differences between apo- and holo-RpAcpXL indicated some differences in the hinge region between α2 and α3 and in the hydrophobic cavity environment, but corresponding changes in nuclear Overhauser effect cross-peak patterns were not detected. In contrast to the NMR structures, apo-RpAcpXL was observed in an open conformation in crystals that diffracted to 2.0 Å resolution, which resulted from movement of α3. On the basis of the crystal structure, the predicted biological assembly is a homodimer. Although the possible biological significance of dimerization is unknown, there is potential that the resulting large shared hydrophobic cavity could accommodate the very long-chain fatty acid (28-30 carbons) that this specialized ACP is known to synthesize and transfer to lipid A. These structures are the first representatives of the AcpXL family and the first to indicate that dimerization may be important for the function of these specialized ACPs.

  12. Ultrafast energy transfer dynamics of a bioinspired dyad molecule.

    PubMed

    Savolainen, Janne; Dijkhuizen, Niels; Fanciulli, Riccardo; Liddell, Paul A; Gust, Devens; Moore, Thomas A; Moore, Ana L; Hauer, Jürgen; Buckup, Tiago; Motzkus, Marcus; Herek, Jennifer L

    2008-03-06

    A caroteno-purpurin dyad molecule was studied by steady-state and pump-probe spectroscopies to resolve the excited-state deactivation dynamics of the different energy levels as well as the connecting energy flow pathways and corresponding rate constants. The data were analyzed with a two-step multi-parameter global fitting procedure that makes use of an evolutionary algorithm. We found that following ultrafast excitation of the donor (carotenoid) chromophore to its S2 state, the energy flows via two channels: energy transfer (70%) and internal conversion (30%) with time constants of 54 and 110 fs, respectively. Additionally, some of the initial excitation is found to populate the hot ground state, revealing another limitation to the functional efficiency. At later times, a back transfer occurs from the purpurin to the carotenoid triplet state in nanosecond timescales. Details of the energy flow within the dyad as well as species associated spectra are disentangled for all excited-state and ground-state species for the first time. We also observe oscillations with the most pronounced peak on the Fourier transform spectrum having a frequency of 530 cm(-1). The dyad mimics the dynamics of the natural light-harvesting complex LH2 from Rhodopseudomonas acidophila and is hence a good model system to be used in studies aimed to further explain previous work in which the branching ratio between the competing pathways of energy loss and energy transfer could be manipulated by adaptive femtosecond pulse shaping.

  13. Arsenic biotransformation and volatilization in transgenic rice

    PubMed Central

    Meng, Xiang-Yan; Qin, Jie; Wang, Li-Hong; Duan, Gui-Lan; Sun, Guo-Xin; Wu, Hui-Lan; Chu, Cheng-Cai; Ling, Hong-Qing; Rosen, Barry P.; Zhu, Yong-Guan

    2011-01-01

    Summary Biotransformation of arsenic includes oxidation, reduction, methylation and conversion to more complex organic arsenicals. Members of the class of arsenite [As(III)] S-adenosylmethyltransferase enzymes catalyze As(III) methylation to a variety of mono-, di- and trimethylated species, some of which are less toxic than As(III) itself. However, no methyltransferase gene has been identified in plants. Here, an arsM gene from the soil bacterium Rhodopseudomonas palustris was expressed in Japonica rice (Oryza sativa L.) cultivar Nipponbare, and the transgenic rice produced methylated arsenic species, which were measured by inductively coupled plasma mass spectrometry (ICP-MS) and high performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC-ICP-MS). Both monomethylarsenate [MAs(V)] and dimethylarsenate [DMAs(V)] were detected in the root and shoot of transgenic rice. After 12-d exposure to As(III), the transgenic rice gave off 10-fold more volatile arsenicals. The present study demonstrates that expression of an arsM gene in rice induces arsenic methylation and volatilization, providing a potential stratagem for phytoremediation theoretically. PMID:21517874

  14. An optogenetic system based on bacterial phytochrome controllable with near-infrared light

    PubMed Central

    Kaberniuk, Andrii A.; Shemetov, Anton A.; Verkhusha, Vladislav V.

    2016-01-01

    Light-mediated control of protein-protein interactions to regulate metabolic pathways is an important approach of optogenetics. Here, we report the first optogenetic system based on a reversible light-induced binding between a bacterial phytochrome BphP1 and its natural partner PpsR2 from Rhodopseudomonas palustris bacteria. We extensively characterized the BphP1–PpsR2 interaction both in vitro and in mammalian cells, and then used it to translocate target proteins to specific cellular compartments, such as plasma membrane and nucleus. Applying this approach we achieved a light-control of cell morphology resulting in the substantial increase of cell area. We next demonstrated the light-induced gene expression with the 40-fold contrast in cultured cells, 32-fold subcutaneously and 5.7-fold in deep tissues in mice. The unique characteristics of the BphP1–PpsR2 optogenetic system are its sensitivity to 740–780 nm near-infrared light, ability to utilize an endogenous biliverdin chromophore in eukaryotes including mammals, and spectral compatibility with blue-light optogenetic systems. PMID:27159085

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

    PubMed

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

    2017-02-01

    A Rhodobacter capsulatus strain and a photoheterotrophic culture (IZT) were cultivated to produce hydrogen under different light-dark cycles. A dark fermentation effluent (DFE) was used as substrate. It was found that IZT culture had an average cumulative hydrogen production (Paccum H2) of 1300±43mLH2L(-1) under continuous illumination and light-dark cycles of 30 or 60min. In contrast, R. capsulatus reduced its Paccum H2 by 20% under 30:30min light-dark cycles, but tripled its poly-β-hydroxybutyrate (PHB) content (308±2mgPHB gdw(-1)) compared to continuous illumination. The highest PHB content by IZT culture was 178±10mgPHB gdw(-1) under 15:15min light-dark cycles. PCR-DGGE analysis revealed that the IZT culture was mainly composed of Rhodopseudomonas palustris identified with high nucleotide similarity (99%). The evaluated cultures might be used for hydrogen and PHB production. They might provide energy savings by using light-dark cycles and DFE valorization.

  16. Effect of volatile fatty acids mixtures on the simultaneous photofermentative production of hydrogen and polyhydroxybutyrate.

    PubMed

    Cardeña, René; Valdez-Vazquez, Idania; Buitrón, Germán

    2017-02-01

    Purple non-sulfur bacteria generate hydrogen and polyhydroxybutyrate (PHB) as a mechanism for disposing of reducing equivalents generated during substrate consumption. However, both pathways compete for the reducing equivalents released from bacteria growing under certain substrates, thus the formation of hydrogen or PHB is detrimental to the formation of each other. The effect of mixtures of acetic, propionic and butyric acids on the formation of H2 and PHB was evaluated using Box-Behnken design. A bacterial community mainly constituted by Rhodopseudomonas palustris was used as inoculum. It was observed that the three volatile fatty acids had a significant effect on the specific PHB production. However, only the propionic acid had a significant effect on the specific H2 production activity and the highest value was observed when acetate was the main component in the mixture. The maximum values for the specific PHB and hydrogen production rates were 16.4 mg-PHB/g-TSS/day and 391 mL-H2/g-TSS/day, respectively.

  17. Light-driven carbon dioxide reduction to methane by nitrogenase in a photosynthetic bacterium

    PubMed Central

    Fixen, Kathryn R.; Zheng, Yanning; Harris, Derek F.; Shaw, Sudipta; Yang, Zhi-Yong; Dean, Dennis R.; Seefeldt, Lance C.

    2016-01-01

    Nitrogenase is an ATP-requiring enzyme capable of carrying out multielectron reductions of inert molecules. A purified remodeled nitrogenase containing two amino acid substitutions near the site of its FeMo cofactor was recently described as having the capacity to reduce carbon dioxide (CO2) to methane (CH4). Here, we developed the anoxygenic phototroph, Rhodopseudomonas palustris, as a biocatalyst capable of light-driven CO2 reduction to CH4 in vivo using this remodeled nitrogenase. Conversion of CO2 to CH4 by R. palustris required constitutive expression of nitrogenase, which was achieved by using a variant of the transcription factor NifA that is able to activate expression of nitrogenase under all growth conditions. Also, light was required for generation of ATP by cyclic photophosphorylation. CH4 production by R. palustris could be controlled by manipulating the distribution of electrons and energy available to nitrogenase. This work shows the feasibility of using microbes to generate hydrocarbons from CO2 in one enzymatic step using light energy. PMID:27551090

  18. Energy transfers in the B808-866 antenna from the green bacterium Chloroflexus aurantiacus.

    PubMed

    Novoderezhkin, V I; Taisova, A S; Fetisova, Z G; Blankenship, R E; Savikhin, S; Buck, D R; Struve, W S

    1998-04-01

    Energy transfers within the B808-866 BChl a antenna in chlorosome-membrane complexes from the green photosynthetic bacterium Chloroflexus aurantiacus were studied in two-color pump-probe experiments at room temperature. The steady-state spectroscopy and protein sequence of the B808-866 complex are reminiscent of well-studied LH2 antennas from purple bacteria. B808-->B866 energy transfers occur with approximately 2 ps kinetics; this is slower by a factor of approximately 2 than B800-->B850 energy transfers in LH2 complexes from Rhodopseudomonas acidophila or Rhodobacter sphaeroides. Anisotropy studies show no evidence for intra-B808 energy transfers before the B808-->B866 step; intra-B866 processes are reflected in 350-550 fs anisotropy decays. Two-color anisotropies under 808 nm excitation suggest the presence of a B808-->B866 channel arising either from direct laser excitation of upper B866 exciton components that overlap the B808 absorption band or from excitation of B866 vibronic bands in nontotally symmetric modes.

  19. Tracking energy transfer between light harvesting complex 2 and 1 in photosynthetic membranes grown under high and low illumination.

    PubMed

    Lüer, Larry; Moulisová, Vladimíra; Henry, Sarah; Polli, Dario; Brotosudarmo, Tatas H P; Hoseinkhani, Sajjad; Brida, Daniele; Lanzani, Guglielmo; Cerullo, Giulio; Cogdell, Richard J

    2012-01-31

    Energy transfer (ET) between B850 and B875 molecules in light harvesting complexes LH2 and LH1/RC (reaction center) complexes has been investigated in membranes of Rhodopseudomonas palustris grown under high- and low-light conditions. In these bacteria, illumination intensity during growth strongly affects the type of LH2 complexes synthesized, their optical spectra, and their amount of energetic disorder. We used a specially built femtosecond spectrometer, combining tunable narrowband pump with broadband white-light probe pulses, together with an analytical method based on derivative spectroscopy for disentangling the congested transient absorption spectra of LH1 and LH2 complexes. This procedure allows real-time tracking of the forward (LH2 → LH1) and backward (LH2←LH1) ET processes and unambiguous determination of the corresponding rate constants. In low-light grown samples, we measured lower ET rates in both directions with respect to high-light ones, which is explained by reduced spectral overlap between B850 and B875 due to partial redistribution of oscillator strength into a higher energetic exciton transition. We find that the low-light adaptation in R. palustris leads to a reduced elementary backward ET rate, in accordance with the low probability of two simultaneous excitations reaching the same LH1/RC complex under weak illumination. Our study suggests that backward ET is not just an inevitable consequence of vectorial ET with small energetic offsets, but is in fact actively managed by photosynthetic bacteria.

  20. Crystal Structures of Malonyl-Coenzyme A Decarboxylase Provide Insights into Its Catalytic Mechanism and Disease-Causing Mutations

    PubMed Central

    Froese, D. Sean; Forouhar, Farhad; Tran, Timothy H.; Vollmar, Melanie; Kim, Yi Seul; Lew, Scott; Neely, Helen; Seetharaman, Jayaraman; Shen, Yang; Xiao, Rong; Acton, Thomas B.; Everett, John K.; Cannone, Giuseppe; Puranik, Sriharsha; Savitsky, Pavel; Krojer, Tobias; Pilka, Ewa S.; Kiyani, Wasim; Lee, Wen Hwa; Marsden, Brian D.; von Delft, Frank; Allerston, Charles K.; Spagnolo, Laura; Gileadi, Opher; Montelione, Gaetano T.; Oppermann, Udo; Yue, Wyatt W.; Tong, Liang

    2013-01-01

    Summary Malonyl-coenzyme A decarboxylase (MCD) is found from bacteria to humans, has important roles in regulating fatty acid metabolism and food intake, and is an attractive target for drug discovery. We report here four crystal structures of MCD from human, Rhodopseudomonas palustris, Agrobacterium vitis, and Cupriavidus metallidurans at up to 2.3 Å resolution. The MCD monomer contains an N-terminal helical domain involved in oligomerization and a C-terminal catalytic domain. The four structures exhibit substantial differences in the organization of the helical domains and, consequently, the oligomeric states and intersubunit interfaces. Unexpectedly, the MCD catalytic domain is structurally homologous to those of the GCN5-related N-acetyltransferase superfamily, especially the curacin A polyketide synthase catalytic module, with a conserved His-Ser/Thr dyad important for catalysis. Our structures, along with mutagenesis and kinetic studies, provide a molecular basis for understanding pathogenic mutations and catalysis, as well as a template for structure-based drug design. PMID:23791943

  1. Unified analysis of ensemble and single-complex optical spectral data from light-harvesting complex-2 chromoproteins for gaining deeper insight into bacterial photosynthesis

    NASA Astrophysics Data System (ADS)

    Pajusalu, Mihkel; Kunz, Ralf; Rätsep, Margus; Timpmann, Kõu; Köhler, Jürgen; Freiberg, Arvi

    2015-11-01

    Bacterial light-harvesting pigment-protein complexes are very efficient at converting photons into excitons and transferring them to reaction centers, where the energy is stored in a chemical form. Optical properties of the complexes are known to change significantly in time and also vary from one complex to another; therefore, a detailed understanding of the variations on the level of single complexes and how they accumulate into effects that can be seen on the macroscopic scale is required. While experimental and theoretical methods exist to study the spectral properties of light-harvesting complexes on both individual complex and bulk ensemble levels, they have been developed largely independently of each other. To fill this gap, we simultaneously analyze experimental low-temperature single-complex and bulk ensemble optical spectra of the light-harvesting complex-2 (LH2) chromoproteins from the photosynthetic bacterium Rhodopseudomonas acidophila in order to find a unique theoretical model consistent with both experimental situations. The model, which satisfies most of the observations, combines strong exciton-phonon coupling with significant disorder, characteristic of the proteins. We establish a detailed disorder model that, in addition to containing a C2-symmetrical modulation of the site energies, distinguishes between static intercomplex and slow conformational intracomplex disorders. The model evaluations also verify that, despite best efforts, the single-LH2-complex measurements performed so far may be biased toward complexes with higher Huang-Rhys factors.

  2. Dark States in the Light-Harvesting complex 2 Revealed by Two-dimensional Electronic Spectroscopy

    NASA Astrophysics Data System (ADS)

    Ferretti, Marco; Hendrikx, Ruud; Romero, Elisabet; Southall, June; Cogdell, Richard J.; Novoderezhkin, Vladimir I.; Scholes, Gregory D.; van Grondelle, Rienk

    2016-02-01

    Energy transfer and trapping in the light harvesting antennae of purple photosynthetic bacteria is an ultrafast process, which occurs with a quantum efficiency close to unity. However the mechanisms behind this process have not yet been fully understood. Recently it was proposed that low-lying energy dark states, such as charge transfer states and polaron pairs, play an important role in the dynamics and directionality of energy transfer. However, it is difficult to directly detect those states because of their small transition dipole moment and overlap with the B850/B870 exciton bands. Here we present a new experimental approach, which combines the selectivity of two-dimensional electronic spectroscopy with the availability of genetically modified light harvesting complexes, to reveal the presence of those dark states in both the genetically modified and the wild-type light harvesting 2 complexes of Rhodopseudomonas palustris. We suggest that Nature has used the unavoidable charge transfer processes that occur when LH pigments are concentrated to enhance and direct the flow of energy.

  3. Comparative analysis of microbial community between different cathode systems of microbial fuel cells for denitrification.

    PubMed

    Li, Chao; Xu, Ming; Lu, Yi; Fang, Fang; Cao, Jiashun

    2016-01-01

    Two types of cathodic biofilm in microbial fuel cells (MFC) were established for comparison on their performance and microbial communities. Complete autotrophic simultaneous nitrification and denitrification (SND) without organics addition was achieved in nitrifying-MFC (N-MFC) with a total nitrogen (TN) removal rate of 0.35 mg/(L·h), which was even higher than that in denitrifying-MFC (D-MFC) at same TN level. Integrated denaturing gradient gel electrophoresis analysis based on both 16S rRNA and nirK genes showed that Alpha-, Gammaproteobacteria were the main denitrifier communities. Some potential autotrophic denitrifying bacteria which can use electrons and reducing power from cathodes, such as Shewanella oneidensis, Shewanella loihica, Pseudomonas aeruginosa, Starkeya novella and Rhodopseudomonas palustris were identified and selectively enriched on cathode biofilms. Further, relative abundance of denitrifying bacteria characterized by nirK/16S ratios was much higher in biofilm than suspended sludge according to real-time polymerase chain reaction. The highest enrichment efficiency for denitrifiers was obtained in N-MFC cathode biofilms, which confirmed autotrophic denitrifying bacteria enrichment is the key factor for a D-MFC system.

  4. Circular Dichroism of Carotenoids in Bacterial Light-Harvesting Complexes: Experiments and Modeling

    PubMed Central

    Georgakopoulou, S.; van Grondelle, R.; van der Zwan, G.

    2004-01-01

    In this work we investigate the origin and characteristics of the circular dichroism (CD) spectrum of rhodopin glucoside and lycopene in the light-harvesting 2 complex of Rhodopseudomonas acidophila and Rhodospirillum molischianum, respectively. We successfully model their absorption and CD spectra based on the high-resolution structures. We assume that these spectra originate from seven interacting transition dipole moments: the first corresponds to the 0-0 transition of the carotenoid, whereas the remaining six represent higher vibronic components of the S2 state. From the absorption spectra we get an estimate of the Franck-Condon factors of these transitions. Furthermore, we investigate the broadening mechanisms that lead to the final shape of the spectra and get an insight into the interaction energy between carotenoids. Finally, we examine the consequences of rotations of the carotenoid transition dipole moment and of deformations in the light-harvesting 2 complex rings. Comparison of the modeled carotenoid spectra with modeled spectra of the bacteriochlorophyll QY region leads to a refinement of the modeling procedure and an improvement of all calculated results. We therefore propose that the combined carotenoid and bacteriochlorophyll CD can be used as an accurate reflection of the overall structure of the light-harvesting complexes. PMID:15326029

  5. Mechanistic studies on the phytylation and methylation steps in bacteriochlorophyll a biosynthesis: an application of the /sup 18/O-induced isotope effect in /sup 13/C NMR

    SciTech Connect

    Emery, V.C.; Akhtar, M.

    1987-02-24

    The high-resolution /sup 13/C NMR spectrum of bacteriochlorophyll a biosynthesized from (1-/sup 13/C,1,1,4-/sup 18/O/sub 3/)-5-aminolevulinic acid by growing cells of Rhodopseudomonas sphaeroides has shown both the C-17/sup 3/ and C-13/sup 3/ resonances consist of three additional components upfield shifted from the -/sup 16/O- /sup 13/C double bond /sup 16/O resonance. By comparison with the /sup 13/C NMR spectrum obtained for phytyl acetate containing /sup 13/C and /sup 18/O selectively in the ester linkage, these components have been identified as the bridge (-/sup 18/O- /sup 13/C double bond /sup 16/O), non bridge (-/sup 16/O-/sup 13/C double bond /sup 18/O), and dual-labeled (-/sup 18/O-/sup 13/C double bond /sup 18/O) isotopomers, These results have been interpreted to suggest that both the ester bonds of bacteriochlorophyll a are produced by a carboxy-alklyl transfer process.

  6. [Influence of iron on siderophore and photosynthetic pigments biosynthesis by siderophore-producing Rhodopesudomonnas palustris].

    PubMed

    Hu, Bihui; Zhao, Chungui; Yang, Suping

    2014-04-04

    To explore the regulation of iron on siderophore production, cell growth and photosynthetic pigments biosynthesis by siderophore-producing anoxygenic phototrophic bacteria. Siderophore production was determined using Chrome Azurol S (CAS) assay. The siderophore types were determined by Arnow method, Csaky test and Shenker test. The compositions and contents of photosynthetic pigments were determined by spectrophotometry and HPLC analysis. Rhodopseudomonas palustris (Rps. palustris) CQV97 was capable of producing hydroxamate-type of siderophore. Siderophore production reached the highest yield in the absence of ferric chloride. With increasing ferric chloride concentrations, the lag phase of cell growth was shortened, and the cell growth rate, final biomass and the total amounts of carotenoid and bacteriochlorophyll a were increased significantly. The characteristic absorption maxima of carotenoids from pigment extracts were blueshifted. Iron concentration had little effect on the compositions and relative contents of bacteriochlorophylls a, whereas predominately affected carotenoid compositions, rhodopin was present as major carotenoid component instead of spirillxanthin. Culture tends to accumulate the Cars having shorter conjugated double bonds at the expense of longer conjugated double bonds as the ferric chloride concentration increased. The changes in carotenoid composition were consistent with those of the blue shift of absorption spectra of pigment extracts. Rps. palustris CQV97 can produce siderophore and the changes in microbial growth, siderophore production and photosynthetic pigments accumulation of anoxygenic phototrophic bacteria are related to the iron concentration in the medium.

  7. Evaluation of colors in green mutants isolated from purple bacteria as a host for colorimetric whole-cell biosensors.

    PubMed

    Yoshida, Kazuyuki; Yoshioka, Daiki; Inoue, Koichi; Takaichi, Shinichi; Maeda, Isamu

    2007-10-01

    The change in carotenoid-based bacterial color from yellow to red can be applied to whole-cell biosensors. We generated several green mutants to emphasize the color change in such biosensors. The blue-green crtI-deleted mutant, Rhodopseudomonas palustris no.711, accumulated the colorless carotenoid precursor, phytoene. Green Rhodovulum sulfidophilum M31 accumulated neurosporene, a downstream product of phytoene. Another green mutant, Rhodobacter sphaeroides Ga, accumulated neurosporene and chloroxanthin, which are both downstream products of phytoene. All green mutants accumulated bacteriochlorophyll a. Photosynthetic membrane obtained from the green mutants all exhibited decreased absorption of wavelength range at 510-570 nm. Therefore, these indicate that the greenish bacterial colors were mainly caused by the existence of bacteriochlorophyll a and the changes in carotenoid composition in photosynthetic membrane. The colors of the green mutants and their wild-type strains were plotted in the CIE-L*a*b* color space, and the color difference (DeltaE*ab) values between a green mutant and its wild type were calculated. DeltaE*ab values were higher in the green mutants than in Rdv. sulfidophilum CDM2, the yellowish host strain of reported biosensors. These data indicate that change in bacterial color from green to red is more distinguishable than that from yellow to red as a reporter signal of carotenoid-based whole-cell biosensors.

  8. Hydrogen production by immobilized R. faecalis RLD-53 using soluble metabolites from ethanol fermentation bacteria E. harbinense B49.

    PubMed

    Liu, Bing-Feng; Ren, Nan-Qi; Xing, De-Feng; Ding, Jie; Zheng, Guo-Xiang; Guo, Wan-Qian; Xu, Ji-Fei; Xie, Guo-Jun

    2009-05-01

    In order to increase the hydrogen yield from glucose, hydrogen production by immobilized Rhodopseudomonas faecalis RLD-53 using soluble metabolites from ethanol fermentation bacteria Ethanoligenens harbinense B49 was investigated. The soluble metabolites from dark-fermentation mainly were ethanol and acetate, which could be further utilized for photo-hydrogen production. Hydrogen production by B49 was noticeably affected by the glucose and phosphate buffer concentration. The maximum hydrogen yield (1.83 mol H(2)/mol glucose) was obtained at 9 g/l glucose. In addition, we found that the ratio of acetate/ethanol (A/E) increased with increasing phosphate buffer concentration, which is favorable to further photo-hydrogen production. The total hydrogen yield during dark- and photo-fermentation reached its maximum value (6.32 mol H(2)/mol glucose) using 9 g/l glucose, 30 mmol/l phosphate buffers and immobilized R. faecalis RLD-53. Results demonstrated that the combination of dark- and photo- fermentation was an effective and efficient process to improve hydrogen yield from a single substrate.

  9. Polyphasic analysis of an Azoarcus-Leptothrix-dominated bacterial biofilm developed on stainless steel surface in a gasoline-contaminated hypoxic groundwater.

    PubMed

    Benedek, Tibor; Táncsics, András; Szabó, István; Farkas, Milán; Szoboszlay, Sándor; Fábián, Krisztina; Maróti, Gergely; Kriszt, Balázs

    2016-05-01

    Pump and treat systems are widely used for hydrocarbon-contaminated groundwater remediation. Although biofouling (formation of clogging biofilms on pump surfaces) is a common problem in these systems, scarce information is available regarding the phylogenetic and functional complexity of such biofilms. Extensive information about the taxa and species as well as metabolic potential of a bacterial biofilm developed on the stainless steel surface of a pump submerged in a gasoline-contaminated hypoxic groundwater is presented. Results shed light on a complex network of interconnected hydrocarbon-degrading chemoorganotrophic and chemolitotrophic bacteria. It was found that besides the well-known hydrocarbon-degrading aerobic/facultative anaerobic biofilm-forming organisms (e.g., Azoarcus, Leptothrix, Acidovorax, Thauera, Pseudomonas, etc.), representatives of Fe(2+)-and Mn(2+)-oxidizing (Thiobacillus, Sideroxydans, Gallionella, Rhodopseudomonas, etc.) as well as of Fe(3+)- and Mn(4+)-respiring (Rhodoferax, Geobacter, Magnetospirillum, Sulfurimonas, etc.) bacteria were present in the biofilm. The predominance of β-Proteobacteria within the biofilm bacterial community in phylogenetic and functional point of view was revealed. Investigation of meta-cleavage dioxygenase and benzylsuccinate synthase (bssA) genes indicated that within the biofilm, Azoarcus, Leptothrix, Zoogloea, and Thauera species are most probably involved in intrinsic biodegradation of aromatic hydrocarbons. Polyphasic analysis of the biofilm shed light on the fact that subsurface microbial accretions might be reservoirs of novel putatively hydrocarbon-degrading bacterial species. Moreover, clogging biofilms besides their detrimental effects might supplement the efficiency of pump and treat systems.

  10. A New Hydrogen-Producing Strain and Its Characterization of Hydrogen Production.

    PubMed

    Sun, Mingxing; Lv, Yongkang; Liu, Yuxiang

    2015-12-01

    A newly isolated photo non-sulfur (PNS) bacterium was identified as Rhodopseudomonas palustris PB-Z by sequencing of 16S ribosomal DNA (rDNA) genes and phylogenetic analysis. Under vigorous stirring (240 rpm), the hydrogen production performances were greatly improved: The maximum hydrogen production rate and cumulative hydrogen production increased by 188.9 ± 0.07 % and 83.0 ± 0.06 %, respectively, due to the hydrogen bubbles were immediately removed from the culture medium. The effects of different wavelength of light on hydrogen production with stirring were much different from that without stirring. The ranking on the photo-hydrogen production performance was white > yellow > green > blue > red without stirring and white > yellow > blue > red > green under stirring. The best light source for hydrogen production was tungsten filament lamp. The optimum temperature was 35 °C. The maximal hydrogen production rate and cumulative hydrogen production reached 78.7 ± 2.3 ml/l/h and 1728.1 ± 92.7 mol H2/l culture, respectively, under 35 °C, 240 rpm, and illumination of 4000 lux. Pyruvate was one of the main sources of CO2 and has a great impact on the gas composition.

  11. Effect of carbon sources on the aggregation of photo fermentative bacteria induced by L-cysteine for enhancing hydrogen production.

    PubMed

    Xie, Guo-Jun; Liu, Bing-Feng; Ding, Jie; Wang, Qilin; Ma, Chao; Zhou, Xu; Ren, Nan-Qi

    2016-12-01

    Poor flocculation of photo fermentative bacteria resulting in continuous biomass washout from photobioreactor is a critical challenge to achieve rapid and stable hydrogen production. In this work, the aggregation of Rhodopseudomonas faecalis RLD-53 was successfully developed in a photobioreactor and the effects of different carbon sources on hydrogen production and aggregation ability were investigated. Extracellular polymeric substances (EPS) production by R. faecalis RLD-53 cultivated using different carbon sources were stimulated by addition of L-cysteine. The absolute ζ potentials of R. faecalis RLD-53 were considerably decreased with addition of L-cysteine, and aggregation barriers based on DLVO dropped to 15-43 % of that in control groups. Thus, R. faecalis RLD-53 flocculated effectively, and aggregation abilities of strain RLD-53 cultivated with acetate, propionate, lactate and malate reached 29.35, 32.34, 26.07 and 24.86 %, respectively. In the continuous test, hydrogen-producing activity was also promoted and reached 2.45 mol H2/mol lactate, 3.87 mol H2/mol propionate and 5.10 mol H2/mol malate, respectively. Therefore, the aggregation of R. faecalis RLD-53 induced by L-cysteine is independent on the substrate types, which ensures the wide application of this technology to enhance hydrogen recovery from wastewater dominated by different organic substrates.

  12. Fluorescence Spectroscopy of Conformational Changes of Single LH2 Complexes

    PubMed Central

    Rutkauskas, Danielis; Novoderezhkin, Vladimir; Cogdell, Richard J.; van Grondelle, Rienk

    2005-01-01

    We have investigated the energy landscape of the bacterial photosynthetic peripheral light-harvesting complex LH2 of purple bacterium Rhodopseudomonas acidophila by monitoring sequences of fluorescence spectra of single LH2 assemblies, at room temperature, with different excitation intensities as well as at elevated temperatures, utilizing a confocal microscope. The fluorescence peak wavelength of individual LH2 complexes was found to abruptly move between long-lived quasi-stable levels differing by up to 30 nm. The frequency and size of these fluorescence peak movements were found to increase linearly with the excitation intensity. These spectral shifts either to the blue or to the red were accompanied by a broadening and decrease of the intensity of the fluorescence spectrum. The probability for a particle to undergo significant spectral shift in either direction was found to be roughly the same. Using the modified Redfield theory, the observed changes in spectral shape and intensity were accounted for by changes in the realization of the static disorder. Long lifetimes of the quasi-stable states suggest large energetic barriers between the states characterized by different emission spectra. PMID:15501944

  13. Picosecond dynamics of primary electron-transfer processes in bacterial photosynthesis.

    PubMed Central

    Peters, K; Avouris, P; Rentzepis, P M

    1978-01-01

    The primary electron transfer processes in Rhodopseudomonas sphaeroides R-26 were studied as a function of temperature by means of picosecond spectroscopy. The first chemical step of the bacterial photosynthesis involves an electron transfer from the excited state of a bacteriochlorophyll a dimer, (BChl)2, to a bacteriopheophytin (BPh) to form the radical ion pair (BChl)2+. BPh-.. The upper limit for the formation time of this ion-pair was found to be 10 ps, at temperatures in the range 300-4.2 degree K. Similarly, the second chemical step, involving electron transfer from BPh-. to an ubiquinone-iron complex (QFe), was found to have a lifetime of approximately 150 ps, also independent of temperature in the same range. We interpret the absence of temperature dependence as indicating that process 2 proceeds via a tunneling mechanism. Utilizing our results in conjunction with electron tunneling theories, we calculate the distance between BPh-. and Q(Fe) to be 9--13 A. Our results also imply a closer proximity between (BChl)2 and BPh. PMID:308379

  14. Polarized potential and electrode materials implication on electro-fermentative di-hydrogen production: Microbial assemblages and hydrogenase gene copy variation.

    PubMed

    Arunasri, Kotakonda; Annie Modestra, J; Yeruva, Dileep Kumar; Vamshi Krishna, K; Venkata Mohan, S

    2016-01-01

    This study examined the changes in microbial diversity in response to different electrode materials viz., stainless steel mesh (SS) and graphite plate as anodes in two microbial electrolysis cell (MEC) each poised at 0.2V, 0.4V, 0.6V and 0.8V. Changes in microbiota prior to and after pretreatment along with microbiota enriched in response to various poised potentials with SS and graphite are monitored by 16S rRNA gene based DGGE profiling. Significant shifts in microbial community were noticed at all these experimental conditions. Correspondingly, the level of hydrogenase belonging to genera Bacillus, Pseudomonas, Rhodopseudomonas and Clostridium was studied by quantitative real time PCR (RT-PCR) at various applied potentials. DGGE based 16S rRNA gene profiling revealed enriched members belonging to phylum Firmicutes predominantly present at 0.8V in both MECs contributing to high hydrogen production. This study first time explored the growth behavior of mixed consortia in response to poised potentials and electrode materials.

  15. Strong shift in the diazotrophic endophytic bacterial community inhabiting rice (Oryza sativa) plants after flooding.

    PubMed

    Ferrando, Lucía; Fernández Scavino, Ana

    2015-09-01

    Flooding impacts soil microbial communities, but its effect on endophytic communities has rarely been explored. This work addresses the effect of flooding on the abundance and diversity of endophytic diazotrophic communities on rice plants established in a greenhouse experiment. The nifH gene was significantly more abundant in roots after flooding, whereas the nifH gene copy numbers in leaves were unaffected and remained low. The PCA (principal component analysis) of T-RFLP (terminal restriction fragment length polymorphism) profiles indicated that root communities of replicate plots were more similar and diverse after flooding than before flooding. The nifH libraries obtained by cloning and 454 pyrosequencing consistently showed a remarkable shift in the diazotrophic community composition after flooding. Gammaproteobacteria (66-98%), mainly of the genus Stenotrophomonas, prevailed in roots before flooding, whereas Betaproteobacteria was the dominant class (26-34%) after flooding. A wide variety of aerotolerant and anaerobic diazotrophic bacteria (e.g. Dechloromonas, Rhodopseudomonas, Desulfovibrio, Geobacter, Chlorobium, Spirochaeta, Selenomonas and Dehalobacter) with diverse metabolic traits were retrieved from flooded rice roots. These findings suggest that endophytic communities could be significantly impacted by changes in plant-soil conditions derived from flooding during rice cropping. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  16. Identification and characterization of transcription networks in environmentally significant species

    SciTech Connect

    Lawrence, Charles E.; McCue, Lee Ann

    2005-11-30

    Understanding the regulation of gene expression, transcription regulation in particular, is one of the grand challenges of molecular biology. Transcription regulation is arguably the most important foundation of cellular function, since it exerts the most fundamental control of the abundance of virtually all of a cell's functional macromolecules. Nevertheless, this process, perhaps because of its difficulty, has been the subject of only a limited number of genomic level analyses. We have undertaken bioinformatics projects to address this issue by developing (1) a cross-species comparison method (i.e. phylogenetic footprinting) for the identification of transcription factor binding sites, (2) a Bayesian clustering method to identify regulons, (3) an improved scanning algorithm that uses a position weight matrix and several related species sequence data to locate transcription factor binding sites, and (4) a method to predict cognate binding sites for transcription factors of unknown specificity. These bioinformatics methods were developed using the model proteobacterium Escherichia coli, with further applications to the genomes of environmentally significant microbes (Rhodopseudomonas palustris, Shewanella oneidensis) in later years of the grant.

  17. Structures of homologous composite transposons carrying cbaABC genes from Europe and North America.

    PubMed

    Di Gioia, D; Peel, M; Fava, F; Wyndham, R C

    1998-05-01

    IS1071 is a class II transposable element carrying a tnpA gene related to the transposase genes of the Tn3 family. Copies of IS1071 that are conserved with more than 99% nucleotide sequence identity have been found as direct repeats flanking a remarkable variety of catabolic gene sequences worldwide. The sequences of chlorobenzoate catabolic transposons found on pBRC60 (Tn5271) in Niagara Falls, N.Y., and on pCPE3 in Bologna, Italy, show that these transposons were formed from highly homologous IS1071 and cbaABC components (levels of identity, > 99.5 and > 99.3%, respectively). Nevertheless, the junction sequences between the IS1071L and IS1071R elements and the internal DNA differ by 41 and 927 bp, respectively, suggesting that these transposons were assembled independently on the two plasmids. The formation of the right junction in both transposons truncated an open reading frame for a putative aryl-coenzyme A ligase with sequence similarity to benzoate- and p-hydroxybenzoate-coenzyme A ligases of Rhodopseudomonas palustris.

  18. A General System for Studying Protein-Protein Interactions in Gram-Negative Bacteria

    SciTech Connect

    Pelletier, Dale A; Auberry, Deanna L; Buchanan, Michelle V; Cannon, Bill; Daly, Don S.; Doktycz, Mitchel John; Foote, Linda J; Hervey, IV, William Judson; Hooker, Brian; Hurst, Gregory {Greg} B; Kennel, Steve J; Lankford, Patricia K; Larimer, Frank W; Lu, Tse-Yuan S; McDonald, W Hayes; McKeown, Catherine K; Morrell-Falvey, Jennifer L; Owens, Elizabeth T; Schmoyer, Denise D; Shah, Manesh B; Wiley, Steven; Wang, Yisong; Gilmore, Jason

    2008-01-01

    Abstract One of the most promising methods for large-scale studies of protein interactions is isolation of an affinity-tagged protein with its in vivo interaction partners, followed by mass spectrometric identification of the copurified proteins. Previous studies have generated affinity-tagged proteins using genetic tools or cloning systems that are specific to a particular organism. To enable protein-protein interaction studies across a wider range of Gram-negative bacteria, we have developed a methodology based on expression of affinity-tagged bait proteins from a medium copy-number plasmid. This construct is based on a broad-host-range vector backbone (pBBR1MCS5). The vector has been modified to incorporate the Gateway DEST vector recombination region, to facilitate cloning and expression of fusion proteins bearing a variety of affinity, fluorescent, or other tags. We demonstrate this methodology by characterizing interactions among subunits of the DNA-dependent RNA polymerase complex in two metabolically versatile Gram-negative microbial species of environmental interest, Rhodopseudomonas palustris CGA010 and Shewanella oneidensis MR-1. Results compared favorably with those for both plasmid and chromosomally encoded affinity-tagged fusion proteins expressed in a model organism, Escherichia coli.

  19. The Shifts of Diazotrophic Communities in Spring and Summer Associated with Coral Galaxea astreata, Pavona decussata, and Porites lutea

    PubMed Central

    Zhang, Yanying; Yang, Qingsong; Ling, Juan; Van Nostrand, Joy D.; Shi, Zhou; Zhou, Jizhong; Dong, Junde

    2016-01-01

    The coral holobiont often resides in oligotrophic waters; both coral cells and their symbiotic dinoflagellates possess ammonium assimilation enzymes and potentially benefit from the nitrogen fixation of coral-associated diazotrophs. However, the seasonal dynamics of coral-associated diazotrophs are not well characterized. Here, the seasonal variations of diazotrophic communities associated with three corals, Galaxea astreata, Pavona decussata, and Porites lutea, were studied using nifH gene amplicon pyrosequencing techniques. Our results revealed a great diversity of coral-associated diazotrophs. nifH sequences related to Alphaproteobacteria, Deltaproteobacteria, and Gammaproteobacteria were ubiquitous and dominant in all corals in two seasons. In contrast with the coral P. decussata, both G. astreata and P. lutea showed significant seasonal changes in the diazotrophic communities and nifH gene abundance. Variable diazotroph groups accounted for a range from 11 to 49% within individual coral samples. Most of the variable diazotrophic groups from P. decussata were species-specific, however, the majority of overlapping variable groups in G. astreata and P. lutea showed the same seasonal variation characteristics. Rhodopseudomonas palustris- and Gluconacetobacter diazotrophicus-affiliated sequences were relatively abundant in the summer, whereas a nifH sequence related to Halorhodospira halophila was relatively abundant in spring G. astreata and P. lutea. The seasonal variations of all diazotrophic communities were significantly correlated with the seasonal shifts of ammonium and nitrate, suggesting that diazotrophs play an important role in the nitrogen cycle of the coral holobiont. PMID:27920768

  20. Performance, carotenoids yield and microbial population dynamics in a photobioreactor system treating acidic wastewater: Effect of hydraulic retention time (HRT) and organic loading rate (OLR).

    PubMed

    Liu, Shuli; Zhang, Guangming; Zhang, Jie; Li, Xiangkun; Li, Jianzheng

    2016-01-01

    Effects of hydraulic retention time (HRT) and influent organic loading rate (OLR) were investigated in a photobioreactor containing PNSB (Rhodopseudomonas palustris)-chemoheterotrophic bacteria to treat volatile fatty acid wastewater. Pollutants removal, biomass production and carotenoids yield in different phases were investigated in together with functional microbial population dynamics. The results indicated that properly decreasing HRT and increasing OLR improved the nutrient removal performance as well as the biomass and carotenoids productions. 85.7% COD, 89.9% TN and 91.8% TP removals were achieved under the optimal HRT of 48h and OLR of 2.51g/L/d. Meanwhile, the highest biomass production and carotenoids yield were 2719.3mg/L and 3.91mg/g-biomass respectively. In addition, HRT and OLR have obvious impacts on PNSB and total bacteria dynamics. Statistical analyses indicated that the COD removal exhibited a positive relationship with OLR, biomass and carotenoids production. PNSB/total bacteria ratio had a positive correlation with the carotenoids yield. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. [Biodegradation characteristics of o-chlorophenol with photosynthetic bacteria PSB-1D].

    PubMed

    Hu, Xiao-min; Dong, Yi-hu; Li, Liang; Lu, Juan; He, Ying-dian; Gao, Yang

    2010-07-01

    A strain of photosynthetic bacteria named PSB-1D with degradation of o-chlorophenol (2-CP) was isolated and screened from the shallow substrate sludge in downstream side of the sewage outfall of an insecticide factory. The PSB-1D is identified preliminarily as Rhodopseudomonas sp. according to its colony and cell morphological properties, physiological biochemical characteristics and absorption spectrum analysis of living cells. The experiments results of relationship between PSB-1D growth and o-chlorophenol degradation showed that the degradation rate of o-chlorophenol was up to 57.26% after 7 days cultural time. The main environmental factors including way of illumination and oxygen, initial pH, cultural temperature, illumination intensity had distinctly influenced on the o-chlorophenol degradation with PSB-1D. The results showed that the optimum conditions were as following: an anaerobic light, pH 7.0, temperature 30 degrees C, illumination intensity 4000 lx,initial o-chlorophenol concentration 50 mg/L. Under that cultural condition, the degradation rate of o-chlorophenol could reach to 62.08%. The degradation kinetic data fitted the Andrews model well. In addition, the biodegradation process of o-chlorophenol can be well described by enzymatic reaction of high concentration inhibition, with the maximum substrate utilization rate 0.309 d(-1), Michaelis-Menten constant 2.733 mg/L, inhibitory constant 230.15 mg/L respectively.

  2. Phylogenetic diversity of hpnP, the hopanoid methylase, and its implications for 2-methylhopanoids as biomarkers

    NASA Astrophysics Data System (ADS)

    Ricci, J. N.; Coleman, M. L.; Osburn, M. R.; Sessions, A. L.; Spear, J. R.; Newman, D. K.

    2011-12-01

    Hopanoids are a class of sterols produced by bacteria. Their hydrocarbon skeletons are resistant to degradation making their diagenetic products, hopanes, attractive biomarkers. Particular attention has been paid to 2-methylhopanes, which have been found at discrete times and locations in Earth history as far back as 2,500 Myr. Previously, they were inferred to be markers of oxygenic photosynthesis in cyanobacteria, but the discovery of an anoxygenic phototroph, Rhodopseudomonas palustris TIE-1, capable of producing significant quantities of 2-methylbacteriohopanetetrol, the parent molecule of the fossil 2-methylhopane, challenged this interpretation. In this study, we sought to determine the diversity and origin of the enzyme responsible for methylating hopanoids, HpnP. To accomplish this task, we surveyed a diversity of Yellowstone hot springs using degenerate PCR primers and searched publically available metagenomic databases for hpnP-like sequences. The Yellowstone hot spring samples were dominated by cyanobacterial-like hpnP sequences, while the metagenomic data contained many hpnP-like sequences from a diversity of environments that grouped with all known hpnP-containing phyla. With these additional hpnP sequences, we will report updated phylogenetic trees that attempt to determine the origin of hpnP. Understanding the distribution of 2-methylhopanoid production throughout the tree of life and its origin is important to be able to use 2-methylhopanes as biomarkers for any particular taxonomic group.

  3. Size dependent microbial oxidation and reduction of magnetite nano- and micro-particles

    PubMed Central

    Byrne, James M.; van der Laan, Gerrit; Figueroa, Adriana I.; Qafoku, Odeta; Wang, Chongmin; Pearce, Carolyn I.; Jackson, Michael; Feinberg, Joshua; Rosso, Kevin M.; Kappler, Andreas

    2016-01-01

    The ability for magnetite to act as a recyclable electron donor and acceptor for Fe-metabolizing bacteria has recently been shown. However, it remains poorly understood whether microbe-mineral interfacial electron transfer processes are limited by the redox capacity of the magnetite surface or that of whole particles. Here we examine this issue for the phototrophic Fe(II)-oxidizing bacteria Rhodopseudomonas palustris TIE-1 and the Fe(III)-reducing bacteria Geobacter sulfurreducens, comparing magnetite nanoparticles (d ≈ 12 nm) against microparticles (d ≈ 100–200 nm). By integrating surface-sensitive and bulk-sensitive measurement techniques we observed a particle surface that was enriched in Fe(II) with respect to a more oxidized core. This enables microbial Fe(II) oxidation to occur relatively easily at the surface of the mineral suggesting that the electron transfer is dependent upon particle size. However, microbial Fe(III) reduction proceeds via conduction of electrons into the particle interior, i.e. it can be considered as more of a bulk electron transfer process that is independent of particle size. The finding has potential implications on the ability of magnetite to be used for long range electron transport in soils and sediments. PMID:27492680

  4. Nitrogen Fixation (Acetylene Reduction) by Epiphytes of Freshwater Macrophytes

    PubMed Central

    Finke, Linda R.; Seeley, H. W.

    1978-01-01

    The involvement of epiphytic microorganisms in nitrogen fixation was investigated in a shallow freshwater pond near Ithaca, N.Y. The acetylene reduction technique was used to follow diel and seasonal cycles of nitrogen fixation by epiphytes of Myriophyllum spicatum. Acetylene-reducing activity was maximal between noon and 6 p.m., but substantial levels of activity relative to daytime rates continued through the night. Experiments with the seasonal course of activity showed a gradual decline during the autumn months and no activity in January or February. Activity commenced in May, with an abrupt increase to levels between 0.45 and 0.95 nmol of ethylene formed per mg (dry weight) of plant per h. Through most of the summer months, mean rates of acetylene reduction remained between 0.15 and 0.60 nmol/mg (dry weight) per h. It was calculated from diel and seasonal cycles that, in the pond areas studied, epiphytes were capable of adding from 7.5 to 12.5 μg of N per mg of plant per year to the pond. This amount is significant relative to the total amount of nitrogen incorporated into the plant. Blue-green algae (cyanobacteria), particularly Gloeotrichia, appeared to bear prime responsibility for nitrogen fixation, but photosynthetic bacteria of the genus Rhodopseudomonas were isolated from M. spicatum and shown to support high rates of acetylene reduction. PMID:16345301

  5. Nonphotochemical Hole-Burning Studies of Energy Transfer Dynamics in Antenna Complexes of Photosynthetic Bacteria

    SciTech Connect

    Matsuzaki, Satoshi

    2001-01-01

    This thesis contains the candidate's original work on excitonic structure and energy transfer dynamics of two bacterial antenna complexes as studied using spectral hole-burning spectroscopy. The general introduction is divided into two chapters (1 and 2). Chapter 1 provides background material on photosynthesis and bacterial antenna complexes with emphasis on the two bacterial antenna systems related to the thesis research. Chapter 2 reviews the underlying principles and mechanism of persistent nonphotochemical hole-burning (NPHB) spectroscopy. Relevant energy transfer theories are also discussed. Chapters 3 and 4 are papers by the candidate that have been published. Chapter 3 describes the application of NPHB spectroscopy to the Fenna-Matthews-Olson (FMO) complex from the green sulfur bacterium Prosthecochloris aestuarii; emphasis is on determination of the low energy vibrational structure that is important for understanding the energy transfer process associated within three lowest energy Qy-states of the complex. The results are compared with those obtained earlier on the FMO complex from Chlorobium tepidum. In Chapter 4, the energy transfer dynamics of the B800 molecules of intact LH2 and B800-deficient LH2 complexes of the purple bacterium Rhodopseudomonas acidophila are compared. New insights on the additional decay channel of the B800 ring of bacteriochlorophyll a (BChl a) molecules are provided. General conclusions are given in Chapter 5.

  6. Unravelling the Carbon and Sulphur Metabolism in Coastal Soil Ecosystems Using Comparative Cultivation-Independent Genome-Level Characterisation of Microbial Communities

    PubMed Central

    Yousuf, Basit; Kumar, Raghawendra; Mishra, Avinash; Jha, Bhavanath

    2014-01-01

    Bacterial autotrophy contributes significantly to the overall carbon balance, which stabilises atmospheric CO2 concentration and decelerates global warming. Little attention has been paid to different modes of carbon/sulphur metabolism mediated by autotrophic bacterial communities in terrestrial soil ecosystems. We studied these pathways by analysing the distribution and abundance of the diagnostic metabolic marker genes cbbM, apsA and soxB, which encode for ribulose-1,5-bisphosphate carboxylase/oxygenase, adenosine phosphosulphate reductase and sulphate thiohydrolase, respectively, among different contrasting soil types. Additionally, the abundance of community members was assessed by quantifying the gene copy numbers for 16S rRNA, cbbL, cbbM, apsA and soxB. Distinct compositional differences were observed among the clone libraries, which revealed a dominance of phylotypes associated with carbon and sulphur cycling, such as Gammaproteobacteria (Thiohalomonas, Allochromatium, Chromatium, Thiomicrospira) and Alphaproteobacteria (Rhodopseudomonas, Rhodovulum, Paracoccus). The rhizosphere soil was devoid of sulphur metabolism, as the soxB and apsA genes were not observed in the rhizosphere metagenome, which suggests the absence or inadequate representation of sulphur-oxidising bacteria. We hypothesise that the novel Gammaproteobacteria sulphur oxidisers might be actively involved in sulphur oxidation and inorganic carbon fixation, particularly in barren saline soil ecosystems, suggesting their significant putative ecological role and contribution to the soil carbon pool. PMID:25225969

  7. Characteristics of purple nonsulfur bacteria grown under Stevia residue extractions.

    PubMed

    Xu, J; Feng, Y; Wang, Y; Lin, X

    2013-11-01

    As a consequence of the large-scale cultivation of Stevia plants, releases of plant residues, the byproduct after sweetener extraction, to the environment are inevitable. Stevia residue and its effluent after batching up contain large amounts of organic matters with small molecular weight, which therefore are a potential pollution source. Meanwhile, they are favourite substrates for micro-organism growths. This investigation was aimed to utilize the simulated effluent of Stevia residue to enrich the representative purple nonsulfur bacterium (PNSB), Rhodopseudomonas palustris (Rps. palustris), which has important economic values. The growth profile and quality of Rps. palustris were characterized by spectrophotometry, compared to those grown in common PNSB mineral synthetic medium. Our results revealed that the simulated effluent of Stevia residue not only stimulated Rps. palustris growth to a greater extent, but also increased its physiologically active cytochrome concentrations and excreted indole-3-acetic acid (IAA) content. This variation in phenotype of Rps. palustris could result from the shift in its genotype, further revealed by the repetitive sequence-based PCR (rep-PCR) fingerprinting analysis. Our results showed that the effluent of Stevia residue was a promising substrate for microbial growth. © 2013 The Society for Applied Microbiology.

  8. Towards understanding the biological function of hopanoids (Invited)

    NASA Astrophysics Data System (ADS)

    Doughty, D. M.; Hunter, R.; Summons, R. E.; Newman, D. K.

    2010-12-01

    Rhodopseudomonas palustris TIE-1 expresses bacterial hopanoid lipids that are structurally similar and evolutionarily related to eukaryotic sterols. The genome of R. palustris TIE-1 contains two copies of the hpnN gene (hpnN1 and hpnN2) that are orthologs of genes encoding eukaryotic sterol and lipid transporters. Hopanoid localization to the outer membrane was found to be dependent upon hpnN1. Since the cell cycle of R. palustris TIE-1 is obligately bimodal with each cell division resulting in the generation of one mother and one swarmer cell, evidence was obtained that hopanoids where specifically localized to the outer membrane of mother cells. The sequestration of hopanoids to the mother cells was also disrupted by the deletion of the hpnN1 gene. Mutants lacking the hopanoid transporters were able to grow normally at 30 °C but showed decreased growth at 38 °C. The hopanoid transporter mutant formed cellular filaments when grown at elevated temperature. Because sedimentary steranes and hopanes comprise some of the earliest evidence for the emergence of distinct bacteria and eukaryotic phyla, a better appreciation of the function of hopanoids will improve our ability to interpret the evolution of life on Earth.

  9. The use of controlled microbial cenoses in producers' link to increase steady functioning of artificial ecosystems

    NASA Astrophysics Data System (ADS)

    Somova, Lydia; Mikheeva, Galina; Somova, Lydia

    The life support systems (LSS) for long-term missions are to use cycling-recycling systems, including biological recycling. Simple ecosystems include 3 links: producers (plants), consumers (man, animals) and reducers (microorganisms). Microorganisms are substantial component of every link of LSS. Higher plants are the traditional regenerator of air and producer of food. They should be used in many successive generations of their reproduction in LSS. Controlled microbiocenoses can increase productivity of producer's link and protect plants from infections. The goal of this work was development of methodological bases of formation of stable, controlled microbiocenoses, intended for increase of productivity of plants and for obtaining ecologically pure production of plants. Main results of our investigations: 1. Experimental microbiocenoses, has been produced in view of the developed methodology on the basis of natural association of microorganisms by long cultivation on specially developed medium. Dominating groups are bacteria of genera: Lactobacillus, Streptococcus, Leuconostoc, Bifidobacterium, Rhodopseudomonas and yeast of genera: Kluyveromyces, Saccharomyces, Torulopsis. 2. Optimal parameters of microbiocenosis cultivation (t, pH, light exposure, biogenic elements concentrations) were experimentally established. Conditions of cultivation on which domination of different groups of microbiocenosis have been found. 3. It was shown, that processing of seeds of wheat, oats, bulbs and plants Allium cepa L. (an onions) with microbial association raised energy of germination of seeds and bulbs and promoted the increase (on 20-30 %) of growth green biomass and root system of plants in comparison with the control. This work is supported by grant, Yenissey , 07-04-96806

  10. Electron uptake by iron-oxidizing phototrophic bacteria

    SciTech Connect

    Bose, A; Gardel, EJ; Vidoudez, C; Parra, EA; Girguis, PR

    2014-02-26

    Oxidation-reduction reactions underlie energy generation in nearly all life forms. Although most organisms use soluble oxidants and reductants, some microbes can access solid-phase materials as electron-acceptors or -donors via extracellular electron transfer. Many studies have focused on the reduction of solid-phase oxidants. Far less is known about electron uptake via microbial extracellular electron transfer, and almost nothing is known about the associated mechanisms. Here we show that the iron-oxidizing photoautotroph Rhodopseudomonas palustris TIE-1 accepts electrons from a poised electrode, with carbon dioxide as the sole carbon source/electron acceptor. Both electron uptake and ruBisCo form I expression are stimulated by light. Electron uptake also occurs in the dark, uncoupled from photosynthesis. Notably, the pioABC operon, which encodes a protein system essential for photoautotrophic growth by ferrous iron oxidation, influences electron uptake. These data reveal a previously unknown metabolic versatility of photoferrotrophs to use extracellular electron transfer for electron uptake.

  11. Comparison of Digestion Protocols for Microgram Quantities of Enriched Protein Samples

    SciTech Connect

    Hervey, IV, William Judson; Strader, Michael B; Strader, Michael Brad; Hurst, Gregory {Greg} B

    2007-01-01

    Standard biochemical techniques that are used for protein enrichments, such as affinity isolation and density gradient centrifugation, frequently yield high nanogram to low microgram quantities at a significant expenditure of resources and time. The characterization of selected protein enrichments by the "shotgun" mass spectrometry approach is often compromised by the lack of effective and efficient in-solution proteolysis protocols specifically tailored for these small quantities of proteins. This study compares the results of five different digestion protocols that were applied to 2.5 g portions of protein isolates from two disparate sources: Rhodopseudomonas palustris 70S ribosomal proteins, and Bos taurus microtubule-associated proteins (MAPs). Proteolytic peptides produced according to each protocol in each type of protein isolate were analyzed by one-dimensional liquid chromatography-tandem mass spectrometry (LC-MS/MS). The effectiveness of each digestion protocol was assessed on the basis of three parameters: number of peptide identifications, number of protein identifications, and sequence coverage. The two protocols using a solvent containing 80% acetonitrile (CH3CN) for trypsin digestions performed as well as, and in some instances better than, protocols employing other solvents and chaotropes in both types of protein isolates. A primary advantage of the 80% CH3CN protocol is that it requires fewer sample manipulation steps.

  12. Annual report and summaries of FY 1983 activities supported by the Division of Biological Energy Research

    SciTech Connect

    Rabson, R.

    1983-10-01

    Summaries of research performed in FY 1983 are presented. Representative research areas include: (1) progress was made in modifying the Agrobacterium tumefaciens Ti plasmid as a vector in the transfer of DNA in higher plants. The plasmid was disarmed by genetically altering that information which is responsible for unwanted tumor formation in recipient plants. In addition it was demonstrated that antibiotic resistance as a representative genetic character may be transferred by the Ti plasmid to a recipient plant culture; (2) by using appropriately constituted genetic lines of maize it has been possible by following male sterility restorer function to measure for the first time the frequency and character of genetic transposition events in a higher organism; (3) the gene coding for susceptibility to the herbicide atrazine in higher plants has been identified, cloned, and sequenced. A mutant gene which is responsible for resistance to the herbicide has likewise been studied. The difference between the two is one nucleotide in the DNA sequence; and (4) amino acid sequences of a number of proteins of the smallest functional photosynthetic particle, known as the reaction center, of the photosynthetic bacterium Rhodopseudomonas capsulata have been determined by cloning and sequencing the corresponding DNA. This information has led to new insights concerning the structural and functional nature of the proteins in photosynthesis.

  13. Dark States in the Light-Harvesting complex 2 Revealed by Two-dimensional Electronic Spectroscopy

    SciTech Connect

    Ferretti, Marco; Hendrikx, Ruud; Romero, Elisabet; Southall, June; Cogdell, Richard J.; Novoderezhkin, Vladimir I.; Scholes, Gregory D.; van Grondelle, Rienk

    2016-02-09

    Energy transfer and trapping in the light harvesting antennae of purple photosynthetic bacteria is an ultrafast process, which occurs with a quantum efficiency close to unity. However the mechanisms behind this process have not yet been fully understood. Recently it was proposed that low-lying energy dark states, such as charge transfer states and polaron pairs, play an important role in the dynamics and directionality of energy transfer. However, it is difficult to directly detect those states because of their small transition dipole moment and overlap with the B850/B870 exciton bands. Here we present a new experimental approach, which combines the selectivity of two-dimensional electronic spectroscopy with the availability of genetically modified light harvesting complexes, to reveal the presence of those dark states in both the genetically modified and the wild-type light harvesting 2 complexes of Rhodopseudomonas palustris. In conclusion, we suggest that Nature has used the unavoidable charge transfer processes that occur when LH pigments are concentrated to enhance and direct the flow of energy.

  14. Introducing capnophilic lactic fermentation in a combined dark-photo fermentation process: a route to unparalleled H2 yields.

    PubMed

    Dipasquale, L; Adessi, A; d'Ippolito, G; Rossi, F; Fontana, A; De Philippis, R

    2015-01-01

    Two-stage process based on photofermentation of dark fermentation effluents is widely recognized as the most effective method for biological production of hydrogen from organic substrates. Recently, it was described an alternative mechanism, named capnophilic lactic fermentation, for sugar fermentation by the hyperthermophilic bacterium Thermotoga neapolitana in CO2-rich atmosphere. Here, we report the first application of this novel process to two-stage biological production of hydrogen. The microbial system based on T. neapolitana DSM 4359(T) and Rhodopseudomonas palustris 42OL gave 9.4 mol of hydrogen per mole of glucose consumed during the anaerobic process, which is the best production yield so far reported for conventional two-stage batch cultivations. The improvement of hydrogen yield correlates with the increase in lactic production during capnophilic lactic fermentation and takes also advantage of the introduction of original conditions for culturing both microorganisms in minimal media based on diluted sea water. The use of CO2 during the first step of the combined process establishes a novel strategy for biohydrogen technology. Moreover, this study opens the way to cost reduction and use of salt-rich waste as feedstock.

  15. Posttranslational modification of a vanadium nitrogenase.

    PubMed

    Heiniger, Erin K; Harwood, Caroline S

    2015-08-01

    In microbes that fix nitrogen, nitrogenase catalyzes the conversion of N2 to ammonia in an ATP-demanding reaction. To help conserve energy some bacteria inhibit nitrogenase activity upon exposure to ammonium. The purple nonsulfur phototrophic bacterium Rhodopseudomonas palustris strain CGA009 can synthesize three functional nitrogenase isoenzymes: a molybdenum nitrogenase, a vanadium nitrogenase, and an iron nitrogenase. Previous studies showed that in some alphaproteobacteria, including R. palustris, molybdenum nitrogenase activity is inhibited by ADP-ribosylation when cells are exposed to ammonium. Some iron nitrogenases are also posttranslationally modified. However, the posttranslational modification of vanadium nitrogenase has not been reported. Here, we investigated the regulation of the alternative nitrogenases of R. palustris and determined that both its vanadium nitrogenase and its iron nitrogenase activities were inhibited and posttranslationally modified when cells are exposed to ammonium. Vanadium nitrogenase is not found in all strains of R. palustris, suggesting that it may have been acquired by horizontal gene transfer. Also, phylogenetic analyses of the three nitrogenases suggest that VnfH, the target of ADP-ribosylation, may be the product of a gene duplication of nifH, the molybdenum nitrogenase homolog.

  16. Agroindustrial residues and energy crops for the production of hydrogen and poly-β-hydroxybutyrate via photofermentation.

    PubMed

    Corneli, Elisa; Adessi, Alessandra; Dragoni, Federico; Ragaglini, Giorgio; Bonari, Enrico; De Philippis, Roberto

    2016-09-01

    The present study was aimed at assessing the biotransformation of dark fermented agroindustrial residues and energy crops for the production of hydrogen and poly-β-hydroxybutyrate (PHB), in lab-scale photofermentation. The investigation on novel substrates for photofermentation is needed in order to enlarge the range of sustainable feedstocks. Dark fermentation effluents of ensiled maize, ensiled giant reed, ensiled olive pomace, and wheat bran were inoculated with Rhodopseudomonas palustris CGA676, a mutant strain suitable for hydrogen production in ammonium-rich media. The highest hydrogen producing performances were observed in wheat bran and maize effluents (648.6 and 320.3mLL(-1), respectively), both characterized by high initial volatile fatty acids (VFAs) concentrations. Giant reed and olive pomace effluents led to poor hydrogen production due to low initial VFAs concentrations, as the original substrates are rich in fiber. The highest PHB content was accumulated in olive pomace effluent (11.53%TS), ascribable to magnesium deficiency. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Metaproteomic identification of diazotrophic methanotrophs and their localization in root tissues of field-grown rice plants.

    PubMed

    Bao, Zhihua; Okubo, Takashi; Kubota, Kengo; Kasahara, Yasuhiro; Tsurumaru, Hirohito; Anda, Mizue; Ikeda, Seishi; Minamisawa, Kiwamu

    2014-08-01

    In a previous study by our group, CH4 oxidation and N2 fixation were simultaneously activated in the roots of wild-type rice plants in a paddy field with no N input; both processes are likely controlled by a rice gene for microbial symbiosis. The present study examined which microorganisms in rice roots were responsible for CH4 oxidation and N2 fixation under the field conditions. Metaproteomic analysis of root-associated bacteria from field-grown rice (Oryza sativa Nipponbare) revealed that nitrogenase complex-containing nitrogenase reductase (NifH) and the alpha subunit (NifD) and beta subunit (NifK) of dinitrogenase were mainly derived from type II methanotrophic bacteria of the family Methylocystaceae, including Methylosinus spp. Minor nitrogenase proteins such as Methylocella, Bradyrhizobium, Rhodopseudomonas, and Anaeromyxobacter were also detected. Methane monooxygenase proteins (PmoCBA and MmoXYZCBG) were detected in the same bacterial group of the Methylocystaceae. Because these results indicated that Methylocystaceae members mediate both CH4 oxidation and N2 fixation, we examined their localization in rice tissues by using catalyzed reporter deposition-fluorescence in situ hybridization (CARD-FISH). The methanotrophs were localized around the epidermal cells and vascular cylinder in the root tissues of the field-grown rice plants. Our metaproteomics and CARD-FISH results suggest that CH4 oxidation and N2 fixation are performed mainly by type II methanotrophs of the Methylocystaceae, including Methylosinus spp., inhabiting the vascular bundles and epidermal cells of rice roots.

  18. Dark States in the Light-Harvesting complex 2 Revealed by Two-dimensional Electronic Spectroscopy

    DOE PAGES

    Ferretti, Marco; Hendrikx, Ruud; Romero, Elisabet; ...

    2016-02-09

    Energy transfer and trapping in the light harvesting antennae of purple photosynthetic bacteria is an ultrafast process, which occurs with a quantum efficiency close to unity. However the mechanisms behind this process have not yet been fully understood. Recently it was proposed that low-lying energy dark states, such as charge transfer states and polaron pairs, play an important role in the dynamics and directionality of energy transfer. However, it is difficult to directly detect those states because of their small transition dipole moment and overlap with the B850/B870 exciton bands. Here we present a new experimental approach, which combines themore » selectivity of two-dimensional electronic spectroscopy with the availability of genetically modified light harvesting complexes, to reveal the presence of those dark states in both the genetically modified and the wild-type light harvesting 2 complexes of Rhodopseudomonas palustris. In conclusion, we suggest that Nature has used the unavoidable charge transfer processes that occur when LH pigments are concentrated to enhance and direct the flow of energy.« less

  19. Electron uptake by iron-oxidizing phototrophic bacteria.

    PubMed

    Bose, A; Gardel, E J; Vidoudez, C; Parra, E A; Girguis, P R

    2014-02-26

    Oxidation-reduction reactions underlie energy generation in nearly all life forms. Although most organisms use soluble oxidants and reductants, some microbes can access solid-phase materials as electron-acceptors or -donors via extracellular electron transfer. Many studies have focused on the reduction of solid-phase oxidants. Far less is known about electron uptake via microbial extracellular electron transfer, and almost nothing is known about the associated mechanisms. Here we show that the iron-oxidizing photoautotroph Rhodopseudomonas palustris TIE-1 accepts electrons from a poised electrode, with carbon dioxide as the sole carbon source/electron acceptor. Both electron uptake and ruBisCo form I expression are stimulated by light. Electron uptake also occurs in the dark, uncoupled from photosynthesis. Notably, the pioABC operon, which encodes a protein system essential for photoautotrophic growth by ferrous iron oxidation, influences electron uptake. These data reveal a previously unknown metabolic versatility of photoferrotrophs to use extracellular electron transfer for electron uptake.

  20. Methylation at the C-2 position of hopanoids increases rigidity in native bacterial membranes

    PubMed Central

    Wu, Chia-Hung; Bialecka-Fornal, Maja; Newman, Dianne K

    2015-01-01

    Sedimentary rocks host a vast reservoir of organic carbon, such as 2-methylhopane biomarkers, whose evolutionary significance we poorly understand. Our ability to interpret this molecular fossil record is constrained by ignorance of the function of their molecular antecedents. To gain insight into the meaning of 2-methylhopanes, we quantified the dominant (des)methylated hopanoid species in the membranes of the model hopanoid-producing bacterium Rhodopseudomonas palustris TIE-1. Fluorescence polarization studies of small unilamellar vesicles revealed that hopanoid 2-methylation specifically renders native bacterial membranes more rigid at concentrations that are relevant in vivo. That hopanoids differentially modify native membrane rigidity as a function of their methylation state indicates that methylation itself promotes fitness under stress. Moreover, knowing the in vivo (2Me)-hopanoid concentration range in different cell membranes, and appreciating that (2Me)-hopanoids' biophysical effects are tuned by the lipid environment, permits the design of more relevant in vitro experiments to study their physiological functions. DOI: http://dx.doi.org/10.7554/eLife.05663.001 PMID:25599566

  1. A general system for studying protein-protein interactions in gram-negative bacteria

    SciTech Connect

    Pelletier, Dale A.; Hurst, G. B.; Foote, Linda J.; Lankford, Patricia K.; McKeown, Cathy K.; Lu, Tse-Yuan S.; Schmoyer, Denise D.; Shah, Manesh B.; Hervey IV, W. J.; McDonald, W. Hayes; Hooker, Brian S.; Cannon, William R.; Daly, Don S.; Gilmore, Jason M.; Wiley, H. S.; Auberry, Deanna L.; Wang, Yisong; Larimer, Frank; Kennel, S. J.; Doktycz, M. J.; Morrell-Falvey, Jennifer; Owens, Elizabeth T.; Buchanan, M. V.

    2008-08-01

    One of the most promising of the emerging methods for large-scale studies of interactions among proteins is co-isolation of an affinity-tagged protein and its interaction partners, followed by mass spectrometric identification of the co-purifying proteins. We describe a methodology for systematically identifying the proteins that interact with affinity-tagged “bait” proteins expressed from a medium copy plasmid, which are based on a broad host range (pBBR1MCS5) vector backbone that has been modified to incorporate the Gateway DEST plasmid multiple cloning region. This construct was designed to facilitate expression of fusion proteins bearing an affinity tag, across a range of Gram negative bacterial hosts. We demonstrate the performance of this methodology by characterizing interactions among subunits of the DNA-dependent RNA polymerase complex in two metabolically versatile Gram negative microbial species of environmental interest, Rhodopseudomonas palustris CGA010 and Shewanella oneidensis MR-1. Results from the RNA polymerase complex from these two species compared favorably with those for both plasmid- and chromosomally-encoded affinity-tagged fusion proteins expressed in a model organism, E. coli.

  2. The ring structure and organization of light harvesting 2 complexes in a reconstituted lipid bilayer, resolved by atomic force microscopy.

    PubMed

    Stamouli, Amalia; Kafi, Sidig; Klein, Dionne C G; Oosterkamp, Tjerk H; Frenken, Joost W M; Cogdell, Richard J; Aartsma, Thijs J

    2003-04-01

    The main function of the transmembrane light-harvesting complexes in photosynthetic organisms is the absorption of a light quantum and its subsequent rapid transfer to a reaction center where a charge separation occurs. A combination of freeze-thaw and dialysis methods were used to reconstitute the detergent-solubilized Light Harvesting 2 complex (LH2) of the purple bacterium Rhodopseudomonas acidophila strain 10050 into preformed egg phosphatidylcholine liposomes, without the need for extra chemical agents. The LH2-containing liposomes opened up to a flat bilayer, which were imaged with tapping and contact mode atomic force microscopy under ambient and physiological conditions, respectively. The LH2 complexes were packed in quasicrystalline domains. The endoplasmic and periplasmic sides of the LH2 complexes could be distinguished by the difference in height of the protrusions from the lipid bilayer. The results indicate that the complexes entered in intact liposomes. In addition, it was observed that the most hydrophilic side, the periplasmic, enters first in the membrane. In contact mode the molecular structure of the periplasmic side of the transmembrane pigment-protein complex was observed. Using Föster's theory for describing the distance dependent energy transfer, we estimate the dipole strength for energy transfer between two neighboring LH2s, based on the architecture of the imaged unit cell.

  3. Volatilization of Arsenic from Polluted Soil by Pseudomonas putida Engineered for Expression of the arsM Arsenic(III) S-Adenosine Methyltransferase Gene

    PubMed Central

    2015-01-01

    Even though arsenic is one of the most widespread environmental carcinogens, methods of remediation are still limited. In this report we demonstrate that a strain of Pseudomonas putida KT2440 endowed with chromosomal expression of the arsM gene encoding the As(III) S-adenosylmethionine (SAM) methyltransfase from Rhodopseudomonas palustris to remove arsenic from contaminated soil. We genetically engineered the P. putida KT2440 with stable expression of an arsM-gfp fusion gene (GE P. putida), which was inserted into the bacterial chromosome. GE P. putida showed high arsenic methylation and volatilization activity. When exposed to 25 μM arsenite or arsenate overnight, most inorganic arsenic was methylated to the less toxic methylated arsenicals methylarsenate (MAs(V)), dimethylarsenate (DMAs(V)) and trimethylarsine oxide (TMAs(V)O). Of total added arsenic, the species were about 62 ± 2.2% DMAs(V), 25 ± 1.4% MAs(V) and 10 ± 1.2% TMAs(V)O. Volatilized arsenicals were trapped, and the predominant species were dimethylarsine (Me2AsH) (21 ± 1.0%) and trimethylarsine (TMAs(III)) (10 ± 1.2%). At later times, more DMAs(V) and volatile species were produced. Volatilization of Me2AsH and TMAs(III) from contaminated soil is thus possible with this genetically engineered bacterium and could be instrumental as an agent for reducing the inorganic arsenic content of soil and agricultural products. PMID:25122054

  4. Nitrogen fixation (acetylene reduction) by epiphytes of freshwater macrophytes.

    PubMed

    Finke, L R; Seeley, H W

    1978-07-01

    The involvement of epiphytic microorganisms in nitrogen fixation was investigated in a shallow freshwater pond near Ithaca, N.Y. The acetylene reduction technique was used to follow diel and seasonal cycles of nitrogen fixation by epiphytes of Myriophyllum spicatum. Acetylene-reducing activity was maximal between noon and 6 p.m., but substantial levels of activity relative to daytime rates continued through the night. Experiments with the seasonal course of activity showed a gradual decline during the autumn months and no activity in January or February. Activity commenced in May, with an abrupt increase to levels between 0.45 and 0.95 nmol of ethylene formed per mg (dry weight) of plant per h. Through most of the summer months, mean rates of acetylene reduction remained between 0.15 and 0.60 nmol/mg (dry weight) per h. It was calculated from diel and seasonal cycles that, in the pond areas studied, epiphytes were capable of adding from 7.5 to 12.5 mug of N per mg of plant per year to the pond. This amount is significant relative to the total amount of nitrogen incorporated into the plant. Blue-green algae (cyanobacteria), particularly Gloeotrichia, appeared to bear prime responsibility for nitrogen fixation, but photosynthetic bacteria of the genus Rhodopseudomonas were isolated from M. spicatum and shown to support high rates of acetylene reduction.

  5. An in vivo imaging-based assay for detecting protein interactions over a wide range of binding affinities

    SciTech Connect

    Fowlkes, Jason Davidson; Owens, Elizabeth T; Standaert, Robert F; Pelletier, Dale A; Hurst, Gregory {Greg} B; Doktycz, Mitchel John; Morrell-Falvey, Jennifer L; Billings, Amanda N

    2009-01-01

    Identifying and characterizing protein interactions are fundamental steps towards understanding and modeling biological networks. Methods that detect protein interactions in intact cells rather than buffered solutions are likely more relevant to natural systems since molecular crowding events in the cytosol can influence the diffusion and reactivity of individual proteins. One in vivo, imaging-based method relies on the co-localization of two proteins of interest fused to DivIVA, a cell division protein from Bacillus subtilis, and green fluorescent protein (GFP). We have modified this imaging-based assay to facilitate rapid cloning by constructing new vectors encoding N- and C-terminal DivIVA or GFP molecular tag fusions based on site-specific recombination technology. The sensitivity of the assay was defined using a well-characterized protein interaction system involving the eukaryotic nuclear import receptor subunit, Importin (Imp ) and variant nuclear localization signals (NLS) representing a range of binding affinities. These data demonstrate that the modified co-localization assay is sensitive enough to detect protein interactions with Kd values that span over four orders of magnitude (1nM to 15 M). Lastly, this assay was used to confirm numerous protein interactions identified from mass spectrometry-based analyses of affinity isolates as part of an interactome mapping project in Rhodopseudomonas palustris

  6. Studies of photosynthetic Energy Conversion

    NASA Astrophysics Data System (ADS)

    Clayton, R. K.; Jagendorf, A. T.

    1985-01-01

    The composition, structure and properties of reaction centers from Rhodopseudomonas viridis were examined. Four distinct polypeptides were found, one of which contains heme groups. Linear dichroism showed the 2 hemes have different orientations in the reaction center. In this bacterium containing BCh1 b, not a, circular dichroism indicated the absence of strong excitonic coupling between the 2 BCh1 b's in the antenna complex. Isolated chromatophores are unusual in not having any detectable ATPase. The intrinsic portion, F/sub O/, is also missing. Equipment improvements included installation of a computer, interfacing with data acquisition systems, and development of programs for rapid analysis of data on absorption, linear or circular dichroism, and fluorescence. The dichroism spectrometer was rebuilt to measure absorbance, linear or circular dichroism in modulated light; and the dual wavelengths spectrometer was updated to greater sensitivity and resolution. A system to combine fluorescence measurements with absorbancy of quinone redox changes was developed, and used to estimate the proportion of alpha and beta centers in a given PSII population.

  7. In Vitro Characterization and Concerted Function of Three Core Enzymes of a Glycyl Radical Enzyme - Associated Bacterial Microcompartment

    PubMed Central

    Zarzycki, Jan; Sutter, Markus; Cortina, Niña Socorro; Erb, Tobias J.; Kerfeld, Cheryl A.

    2017-01-01

    Many bacteria encode proteinaceous bacterial microcompartments (BMCs) that encapsulate sequential enzymatic reactions of diverse metabolic pathways. Well-characterized BMCs include carboxysomes for CO2-fixation, and propanediol- and ethanolamine-utilizing microcompartments that contain B12-dependent enzymes. Genes required to form BMCs are typically organized in gene clusters, which promoted their distribution across phyla by horizontal gene transfer. Recently, BMCs associated with glycyl radical enzymes (GREs) were discovered; these are widespread and comprise at least three functionally distinct types. Previously, we predicted one type of these GRE-associated microcompartments (GRMs) represents a B12-independent propanediol-utilizing BMC. Here we functionally and structurally characterize enzymes of the GRM of Rhodopseudomonas palustris BisB18 and demonstrate their concerted function in vitro. The GRM signature enzyme, the GRE, is a dedicated 1,2-propanediol dehydratase with a new type of intramolecular encapsulation peptide. It forms a complex with its activating enzyme and, in conjunction with an aldehyde dehydrogenase, converts 1,2-propanediol to propionyl-CoA. Notably, homologous GRMs are also encoded in pathogenic Escherichia coli strains. Our high-resolution crystal structures of the aldehyde dehydrogenase lead to a revised reaction mechanism. The successful in vitro reconstitution of a part of the GRM metabolism provides insights into the metabolic function and steps in the assembly of this BMC. PMID:28202954

  8. Production of bio-fuels (hydrogen and lipids) through a photofermentation process.

    PubMed

    Carlozzi, Pietro; Buccioni, Arianna; Minieri, Sara; Pushparaj, Benjamin; Piccardi, Raffaella; Ena, Alba; Pintucci, Cristina

    2010-05-01

    The purple non-sulfur photosynthetic bacteria Rhodopseudomonas palustris (strain 42OL) was investigated for a co-production of both bio-H(2) and biodiesel (lipids). The investigation was carried out using malic and glutamic acids in a fed-batch cultivation system under continuous irradiances of 36, 56, 75, 151, 320, 500, and 803 W m(-2). Boltzmann's sigmoidal regression model was used to determine growth kinetic parameters during hydrogen photoevolution. The upper limit of volumetric hydrogen photoevolution was 15.5 + or - 0.9 ml l(-1) h(-1). During the entire cultivation period (408 h), the highest average hydrogen production rate (HPR(av)) of 11.1 + or - 3.1 ml l(-1) h(-1) was achieved at an irradiance of 320 W m(-2). Biomasses stored at the end of each experimental set were analyzed in order to determine lipid content, which ranged from a minimum of 22 + or - 1% to a maximum of 39 + or - 2% of biomass dry weight. Copyright 2009 Elsevier Ltd. All rights reserved.

  9. Heavy metal tolerant Metalliresistens boonkerdii gen. nov., sp. nov., a new genus in the family Bradyrhizobiaceae isolated from soil in Thailand.

    PubMed

    Noisangiam, Rujirek; Nuntagij, Achara; Pongsilp, Neelawan; Boonkerd, Nantakorn; Denduangboripant, Jessada; Ronson, Clive; Teaumroong, Neung

    2010-11-01

    Bacterial strains from inoculated soybean field soil in Thailand were directly isolated using Bradyrhizobium japonicum selective medium (BJSM), on the basis of Zn(2+) and Co(2+) resistance of B. japonicum and B. elkanii. The isolates were classified into symbiotic and non-symbiotic groups by inoculation assays and Southern hybridization of nod and nif genes. In this study, a nearly full-length 16S rRNA gene sequence showed that the non-symbiotic isolates were more closely related to members of Rhodopseudomonas and to a number of uncultured bacterial clones than to members of Bradyrhizobium. Therefore, a polyphasic study was performed to determine the taxonomic positions of four representatives of the non-symbiotic isolates. Multilocus phylogenetic analysis of individual genes and a combination of the 16S rRNA and three housekeeping genes (atpD, recA and glnII) supported the placement of the non-symbiotic isolates in a different genus. The ability of heavy metal resistance in conjunction with phenotypic analyses, including cellular fatty acid content and biochemical characteristics, showed that the non-symbiotic isolates were differentiated from the other related genera in the family Bradyrhizobiaceae. Therefore, the non-symbiotic isolates represented a novel genus and species, for which the name Metalliresistens boonkerdii gen. nov., sp. nov. is proposed. The type strain is NS23 (= NBRC 106595(T)=BCC 40155(T)).

  10. Volatilization of arsenic from polluted soil by Pseudomonas putida engineered for expression of the arsM Arsenic(III) S-adenosine methyltransferase gene.

    PubMed

    Chen, Jian; Sun, Guo-Xin; Wang, Xiao-Xue; Lorenzo, Víctor de; Rosen, Barry P; Zhu, Yong-Guan

    2014-09-02

    Even though arsenic is one of the most widespread environmental carcinogens, methods of remediation are still limited. In this report we demonstrate that a strain of Pseudomonas putida KT2440 endowed with chromosomal expression of the arsM gene encoding the As(III) S-adenosylmethionine (SAM) methyltransfase from Rhodopseudomonas palustris to remove arsenic from contaminated soil. We genetically engineered the P. putida KT2440 with stable expression of an arsM-gfp fusion gene (GE P. putida), which was inserted into the bacterial chromosome. GE P. putida showed high arsenic methylation and volatilization activity. When exposed to 25 μM arsenite or arsenate overnight, most inorganic arsenic was methylated to the less toxic methylated arsenicals methylarsenate (MAs(V)), dimethylarsenate (DMAs(V)) and trimethylarsine oxide (TMAs(V)O). Of total added arsenic, the species were about 62 ± 2.2% DMAs(V), 25 ± 1.4% MAs(V) and 10 ± 1.2% TMAs(V)O. Volatilized arsenicals were trapped, and the predominant species were dimethylarsine (Me2AsH) (21 ± 1.0%) and trimethylarsine (TMAs(III)) (10 ± 1.2%). At later times, more DMAs(V) and volatile species were produced. Volatilization of Me2AsH and TMAs(III) from contaminated soil is thus possible with this genetically engineered bacterium and could be instrumental as an agent for reducing the inorganic arsenic content of soil and agricultural products.

  11. Bioaugmentation for electricity generation from corn stover biomass using microbial fuel cells.

    PubMed

    Wang, Xin; Feng, Yujie; Wang, Heming; Qu, Youpeng; Yu, Yanling; Ren, Nanqi; Li, Nan; Wang, Elle; Lee, He; Logan, Bruce E

    2009-08-01

    Corn stover is usually treated by an energy-intensive or expensive process to extract sugars for bioenergy production. However, it is possible to directly generate electricity from corn stover in microbial fuel cells (MFCs) through the addition of microbial consortia specifically acclimated for biomass breakdown. A mixed culture that was developed to have a high saccharification rate with corn stover was added to single-chamber, air-cathode MFCs acclimated for power production using glucose. The MFC produced a maximum power of 331 mW/m2 with the bioaugmented mixed culture and corn stover, compared to 510 mW/m2 using glucose. Denaturing gradient gel electrophoresis (DGGE) showed the communities continued to evolve on both the anode and corn stover biomass over 60 days, with several bacteria identified including Rhodopseudomonas palustris. The use of residual solids from the steam exploded corn stover produced 8% more power (406 mW/m2) than the raw corn stover. These results show that it is possible to directly generate electricity from waste corn stover in MFCs through bioaugmentation using naturally occurring bacteria.

  12. Infrared spectroelectrochemistry of bacteriochlorophylls and bacteriopheophytins: Implications for the binding of the pigments in the reaction center from photosynthetic bacteria.

    PubMed

    Mäntele, W G; Wollenweber, A M; Nabedryk, E; Breton, J

    1988-11-01

    The IR spectra of the bacteriochlorophyll a and b cations and the bacteriopheophytin a and b anions were obtained by using an IR and optically transparent electrochemical cell. Prominent effects of radical formation on the vibrational spectra were found for bands assigned to the ester, keto, and acetyl C=O groups and for vibrations from macrocycle bonds. The (radical-minus-neutral) difference spectra are compared to the light-induced difference spectra of the primary donor photooxidation and the intermediary acceptor photoreduction in the reaction center of photosynthetic bacteria. Light-induced absorbance changes from bacteriochlorophyll a-containing reaction centers bear striking similarities to the electrochemically induced absorbance changes observed upon formation of bacteriochlorophyll a(+)in vitro. Comparison of the radical formation in vitro in a hydrogen-bonding or a nonhydrogen-bonding solvent suggests an ester C=O group hydrogen bonded in the neutral state but free in the cation state. For the keto C=O group, the same comparison indicates one free carbonyl group. The (anion-minus-neutral) difference spectra of bacteriopheophytin a and b exhibit a single band in the ester C=O frequency range. In contrast, two bands are observed in the difference spectra of the intermediary acceptor reduction in the reaction center of Rhodopseudomonas viridis. The higher frequency band exhibits a sensitivity to (1)H-(2)H exchange, which suggests a contribution from a protonated carboxyl group of an amino acid side chain.

  13. Unified analysis of ensemble and single-complex optical spectral data from light-harvesting complex-2 chromoproteins for gaining deeper insight into bacterial photosynthesis.

    PubMed

    Pajusalu, Mihkel; Kunz, Ralf; Rätsep, Margus; Timpmann, Kõu; Köhler, Jürgen; Freiberg, Arvi

    2015-01-01

    Bacterial light-harvesting pigment-protein complexes are very efficient at converting photons into excitons and transferring them to reaction centers, where the energy is stored in a chemical form. Optical properties of the complexes are known to change significantly in time and also vary from one complex to another; therefore, a detailed understanding of the variations on the level of single complexes and how they accumulate into effects that can be seen on the macroscopic scale is required. While experimental and theoretical methods exist to study the spectral properties of light-harvesting complexes on both individual complex and bulk ensemble levels, they have been developed largely independently of each other. To fill this gap, we simultaneously analyze experimental low-temperature single-complex and bulk ensemble optical spectra of the light-harvesting complex-2 (LH2) chromoproteins from the photosynthetic bacterium Rhodopseudomonas acidophila in order to find a unique theoretical model consistent with both experimental situations. The model, which satisfies most of the observations, combines strong exciton-phonon coupling with significant disorder, characteristic of the proteins. We establish a detailed disorder model that, in addition to containing a C_{2}-symmetrical modulation of the site energies, distinguishes between static intercomplex and slow conformational intracomplex disorders. The model evaluations also verify that, despite best efforts, the single-LH2-complex measurements performed so far may be biased toward complexes with higher Huang-Rhys factors.

  14. Enhancement of photoheterotrophic biohydrogen production at elevated temperatures by the expression of a thermophilic clostridial hydrogenase.

    PubMed

    Lo, Shou-Chen; Shih, Shau-Hua; Chang, Jui-Jen; Wang, Chun-Ying; Huang, Chieh-Chen

    2012-08-01

    The working temperature of a photobioreactor under sunlight can be elevated above the optimal growth temperature of a microorganism. To improve the biohydrogen productivity of photosynthetic bacteria at higher temperatures, a [FeFe]-hydrogenase gene from the thermophile Clostridium thermocellum was expressed in the mesophile Rhodopseudomonas palustris CGA009 (strain CGA-CThydA) using a log-phase expression promoter P( pckA ) to drive the expression of heterogeneous hydrogenase gene. In contrast, a mesophilic Clostridium acetobutylicum [FeFe]-hydrogenase gene was also constructed and expressed in R. palustris (strain CGA-CAhydA). Both transgenic strains were tested for cell growth, in vivo hydrogen production rate, and in vitro hydrogenase activity at elevated temperatures. Although both CGA-CThydA and CGA-CAhydA strains demonstrated enhanced growth over the vector control at temperatures above 38 °C, CGA-CThydA produced more hydrogen than the other strains. The in vitro hydrogenase activity assay, measured at 40 °C, confirmed that the activity of the CGA-CThydA hydrogenase was higher than the CGA-CAhydA hydrogenase. These results showed that the expression of a thermophilic [FeFe]-hydrogenase in R. palustris increased the growth rate and biohydrogen production at elevated temperatures. This transgenic strategy can be applied to a broad range of purple photosynthetic bacteria used to produce biohydrogen under sunlight.

  15. Evaluation of transgenic tobacco plants expressing a bacterial Co-Ni transporter for acquisition of cobalt.

    PubMed

    Nair, Smitha; Joshi-Saha, Archana; Singh, Sudhir; Ramachandran, V; Singh, Surya; Thorat, Vidya; Kaushik, C P; Eapen, Susan; D'Souza, S F

    2012-11-15

    Phytoremediation is a viable strategy for management of toxic wastes in a large area/volume with low concentrations of toxic elemental pollutants. With increased industrial use of cobalt and its alloys, it has become a major metal contaminant in soils and water bodies surrounding these industries and mining sites with adverse effects on the biota. A bacterial Co-Ni permease was cloned from Rhodopseudomonas palustris and introduced into Nicotiana tabacum to explore its potential for phytoremediation and was found to be specific for cobalt and nickel. The transgenic plants accumulated more cobalt and nickel as compared to control, whereas no significant difference in accumulation of other divalent ions was observed. The transgenic plants were evaluated for cobalt content and showed increased acquisition of cobalt (up to 5 times) as compared to control. The plants were also assessed for accumulation of nickel and found to accumulate up to 2 times more nickel than control. At the same initial concentration of cobalt and nickel, transgenic plant preferentially accumulated cobalt as compared to nickel. The present study is perhaps the first attempt to develop transgenic plants expressing heterologous Co transporter with an improved capacity to uptake cobalt. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Pyrosequencing Reveals a Core Community of Anodic Bacterial Biofilms in Bioelectrochemical Systems from China

    PubMed Central

    Xiao, Yong; Zheng, Yue; Wu, Song; Zhang, En-Hua; Chen, Zheng; Liang, Peng; Huang, Xia; Yang, Zhao-Hui; Ng, I-Son; Chen, Bor-Yann; Zhao, Feng

    2015-01-01

    Bioelectrochemical systems (BESs) are promising technologies for energy and product recovery coupled with wastewater treatment, and the core microbial community in electrochemically active biofilm in BESs remains controversy. In the present study, 7 anodic communities from 6 bioelectrochemical systems in 4 labs in southeast, north and south-central of China are explored by 454 pyrosequencing. A total of 251,225 effective sequences are obtained for 7 electrochemically active biofilm samples at 3% cutoff level. While Alpha-, Beta-, and Gamma-proteobacteria are the most abundant classes (averaging 16.0–17.7%), Bacteroidia and Clostridia are the two sub-dominant and commonly shared classes. Six commonly shared genera i.e., Azospira, Azospirillum, Acinetobacter, Bacteroides, Geobacter, Pseudomonas, and Rhodopseudomonas dominate the electrochemically active communities and are defined as core genera. A total of 25 OTUs with average relative abundance >0.5% were selected and designated as core OTUs, and some species relating to these OTUs have been reported electrochemically active. Furthermore, cyclic voltammetry and chronoamperometry tests show that two strains from Acinetobacter guillouiae and Stappia indica, bacteria relate to two core OTUs, are electrochemically active. Using randomly selected bioelectrochemical systems, the study has presented extremely diverse bacterial communities in anodic biofilms, though, we still can suggest some potentially microbes for investigating the electrochemical mechanisms in bioelectrochemical systems. PMID:26733958

  17. Is there a conserved interaction between cardiolipin and the type II bacterial reaction center?

    PubMed Central

    Wakeham, M C; Sessions, R B; Jones, M R; Fyfe, P K

    2001-01-01

    In a recent publication, the structural details of an interaction between the Rhodobacter sphaeroides reaction center and the anionic phospholipid diphosphatidyl glycerol (cardiolipin) were described (K. E. McAuley, P. K. Fyfe, J. P. Ridge, N. W. Isaacs, R. J. Cogdell, and M. R. Jones, 1999, Proc. Natl. Acad. Sci. U.S.A. 96:14706-14711). This was the first crystallographic description of an interaction between this biologically important lipid and an integral membrane protein and was also the first piece of evidence that the reaction center has a specific interaction with cardiolipin. We have examined the extent to which the residues that interact with the cardiolipin are conserved in other species of photosynthetic bacteria with this type of reaction center and discuss the possibility that this cardiolipin binding site is a conserved feature of these reaction centers. We look at how sequence variations that would affect the shape of the cardiolipin binding site might affect the protein-cardiolipin interaction, by modeling the binding of cardiolipin to the reaction center from Rhodopseudomonas viridis. PMID:11222300

  18. Extension of Light-Harvesting Ability of Photosynthetic Light-Harvesting Complex 2 (LH2) through Ultrafast Energy Transfer from Covalently Attached Artificial Chromophores.

    PubMed

    Yoneda, Yusuke; Noji, Tomoyasu; Katayama, Tetsuro; Mizutani, Naoto; Komori, Daisuke; Nango, Mamoru; Miyasaka, Hiroshi; Itoh, Shigeru; Nagasawa, Yutaka; Dewa, Takehisa

    2015-10-14

    Introducing appropriate artificial components into natural biological systems could enrich the original functionality. To expand the available wavelength range of photosynthetic bacterial light-harvesting complex 2 (LH2 from Rhodopseudomonas acidophila 10050), artificial fluorescent dye (Alexa Fluor 647: A647) was covalently attached to N- and C-terminal Lys residues in LH2 α-polypeptides with a molar ratio of A647/LH2 ≃ 9/1. Fluorescence and transient absorption spectroscopies revealed that intracomplex energy transfer from A647 to intrinsic chromophores of LH2 (B850) occurs in a multiexponential manner, with time constants varying from 440 fs to 23 ps through direct and B800-mediated indirect pathways. Kinetic analyses suggested that B800 chromophores mediate faster energy transfer, and the mechanism was interpretable in terms of Förster theory. This study demonstrates that a simple attachment of external chromophores with a flexible linkage can enhance the light harvesting activity of LH2 without affecting inherent functions of energy transfer, and can achieve energy transfer in the subpicosecond range. Addition of external chromophores, thus, represents a useful methodology for construction of advanced hybrid light-harvesting systems that afford solar energy in the broad spectrum.

  19. Heterologous expression of a bacterial homospermidine synthase gene in transgenic tobacco: effects on the polyamine pathway.

    PubMed

    Kaiser, Annette; Sell, Simone; Hehl, Reinhard

    2002-04-01

    Homospermidine synthase (HSS) is a branch-point enzyme that links the secondary pathway (pyrrolizidine alkaloids) to primary metabolism (polyamines). Since the diamine putrescine is a precursor of homospermidine and nicotine in tobacco, we performed heterologous expression of a bacterial homospermidine synthase gene (hss)in Nicotiana tabacum and determined the effect on free and conjugated polyamine levels. The hss gene from Rhodopseudomonas viridis was placed under the control of the cauliflower mosaic virus (CaMV) 35S promoter in Agrobacterium tumefaciens Ti-plasmid in sense and antisense orientation and both hss constructs were transformed into tobacco plants. Expression of the hss gene was verified by "Northern" and "Southern Blot" analysis. 2 transgenic sense lines were generated from 1000 calli which showed weak expression of homospermidine synthase, i.e. 50 pktal/mg protein and 45 pktal/mg protein. These transgenic sense plants showed a significantly decreased content of free spermidine while the pool of conjugated spermidine was not affected. The 2 sense plants exhibited a range of abnormal phenotypes such as dwarfness and stunted growth. Homospermidine was sporadically detectable in wild type tobacco. To our knowledge, this is the first biotechnological approach to express a prokaryotic homospermidine synthase gene in tobacco plants.

  20. Size dependent microbial oxidation and reduction of magnetite nano- and micro-particles

    NASA Astrophysics Data System (ADS)

    Byrne, James M.; van der Laan, Gerrit; Figueroa, Adriana I.; Qafoku, Odeta; Wang, Chongmin; Pearce, Carolyn I.; Jackson, Michael; Feinberg, Joshua; Rosso, Kevin M.; Kappler, Andreas

    2016-08-01

    The ability for magnetite to act as a recyclable electron donor and acceptor for Fe-metabolizing bacteria has recently been shown. However, it remains poorly understood whether microbe-mineral interfacial electron transfer processes are limited by the redox capacity of the magnetite surface or that of whole particles. Here we examine this issue for the phototrophic Fe(II)-oxidizing bacteria Rhodopseudomonas palustris TIE-1 and the Fe(III)-reducing bacteria Geobacter sulfurreducens, comparing magnetite nanoparticles (d ≈ 12 nm) against microparticles (d ≈ 100–200 nm). By integrating surface-sensitive and bulk-sensitive measurement techniques we observed a particle surface that was enriched in Fe(II) with respect to a more oxidized core. This enables microbial Fe(II) oxidation to occur relatively easily at the surface of the mineral suggesting that the electron transfer is dependent upon particle size. However, microbial Fe(III) reduction proceeds via conduction of electrons into the particle interior, i.e. it can be considered as more of a bulk electron transfer process that is independent of particle size. The finding has potential implications on the ability of magnetite to be used for long range electron transport in soils and sediments.

  1. Alcohol Dehydrogenase from Methylobacterium organophilum

    PubMed Central

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

    1978-01-01

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

  2. Formation of bacteriochlorophyll form B820 in light harvesting 2 complexes from purple sulfur bacteria treated with dioxane.

    PubMed

    Makhneva, Z K; Toropygina, O A; Moskalenko, A A

    2005-10-01

    Treatment of some sulfur bacteria (Allochromatium minutissimum, Thiorhodospira sibirica, and Ectothiorhodospira halovacuolata WN22) with dioxane results in formation of the bacteriochlorophyll form B820 in the light harvesting complex LH2. This form characterized by absorption maximum at 820 nm has the same absorption spectrum as B820 subcomplex from LH1 complex. Appearance of the B820 form was accompanied by a sharp decrease in absorption in the carotenoid region. This phenomenon observed in all LH2 complexes investigated may be attributed to formation of colorless carotenoid aggregates. This is very similar to the previously reported dissociation of the LH1 complex with carotenoids into B820 subcomplexes. Although the B820 form corresponded the bacteriochlorophyll dimer, its circular dichroism spectrum showed that pigment molecules in this dimer exhibit different interaction than those in the B820 subcomplex. The dioxane treatment of LH2 complexes isolated from Rhodopseudomonas palustris bacteria grown under normal or low intensity illumination did not result in formation of such dimers. It is suggested that bacteriochlorophyll B820 formation is related to unique structure of LH2 complexes from the sulfur bacteria.

  3. Preferential incorporation of coloured-carotenoids occurs in the LH2 complexes from non-sulphur purple bacteria under carotenoid-limiting conditions.

    PubMed

    Gall, Andrew; Henry, Sarah; Takaichi, Shinichi; Robert, Bruno; Cogdell, Richard J

    2005-11-01

    The effect of growing Rhodopseudomonas (Rps.) acidophila and Rps. palustris in the presence of different concentrations of the carotenoid (Car) biosynthetic inhibitor diphenylamine (DPA) has been investigated. Growth with sub-maximal concentrations of DPA induces Car limitation. The exact response to DPA is species dependent. However, both Rps. acidophila and Rps. palustris respond by preferentially incorporating the limiting amount of coloured Cars into their LH2 complexes at the expense of the RC-LH1 complexes. As inhibition by DPA becomes more severe there is an increase in the percentage of Cars with reduced numbers of conjugated C=C bonds. The effect of this changed Car composition on the structure and function of the antenna complexes has been investigated using absorption, fluorescence, CD and Raman spectroscopies. The results show that although the presence of Car molecules is important for the stability of the LH2 complexes that the overall native structure can be maintained by the presence of many different Cars.

  4. Optimization of wastewater feeding for single-cell protein production in an anaerobic wastewater treatment process utilizing purple non-sulfur bacteria in mixed culture condition.

    PubMed

    Honda, Ryo; Fukushi, Kensuke; Yamamoto, Kazuo

    2006-10-01

    Impacts of operation timing of feeding and withdrawal on anaerobic wastewater treatment utilizing purple non-sulfur bacteria have been investigated in mixed culture condition with acidogenic bacteria. Simulated wastewater containing glucose was treated in a laboratory-scale chemostat reactor, changing the timing of wastewater feeding and withdrawal. Rhodopseudomonas palustris, which does not utilize glucose as a substrate, was inoculated in the reactor. Rps. palustris was detected by a fluorescent in situ hybridization (FISH) technique using the specific Rpal686 probe. As a result, population ratios of Rps. palustris were over 20% through the operation. Rps. palustris could grow by utilizing metabolites of acidogenic bacteria that coexisted in the reactor. A morning feed was effective for a good growth of purple non-sulfur bacteria. A protein content of cultured bacteria was the highest when wastewater was fed in the morning. Dissolved organic carbon (DOC) removal was 94% independent of the timing control. Consequently, feeding in the morning is the optimum feed-timing control from the aspects of growth of purple non-sulfur bacteria and single-cell protein production.

  5. Polyphosphate metabolism by purple non-sulfur bacteria and its possible application on photo-microbial fuel cell.

    PubMed

    Lai, Yen-Chun; Liang, Chih-Ming; Hsu, Shu-Chuan; Hsieh, Ping-Heng; Hung, Chun-Hsiung

    2017-03-11

    A purple non-sulfur bacterium, Rhodopseudomonas palustris G11, was isolated from an activated sludge plant that treats domestic wastewater. This isolation resulted in the effective accumulation of polyphosphate in cells upon reaching the stationary growth phase. However, when the carbon and/or energy source were/was removed, this bacterium released intracellular polyphosphate or poly-β-hydroxybutyrate to obtain energy to grow or maintain its growth. Furthermore, a novel photo-microbial fuel cell (PMFC) design was proposed. The unique capability of purple non-sulfur bacteria to capture light energy for polyphosphate accumulation was maximized. After R. palustris G11 accumulated considerable polyphosphate and was transferred to a fresh medium, the PMFC system exhibited a maximum voltage of approximately 0.03 V undt illumination. The chemical oxygen demand removal efficiency, Coulomb efficiency, and power density were 95.8%, 0.62%, and 0.15 mW/m(2), respectively. The test microorganisms converted most of the light energy in growth and caused the low power production. The microorganisms grew slowly and produced less power under dark conditions than under light illumination. However, these microorganisms used the previously stored polyphosphate or poly-β-hydroxybutyrate for electricity production when they were incubated in a growth-insufficient condition. This novel concept can be improved and optimized in the future for new PMFC applications, such as rechargeable cells, to treat wastewater and restore energy simultaneously.

  6. Energy transfer and exciton coupling in isolated B800-850 complexes of the photosynthetic purple sulfur bacterium Choromatium tepidum. The effect of structural symmetry on bacteriochlorophyll excited states

    SciTech Connect

    Kennis, J.T.M.; Streltsov, A.M.; Aartsma, T.J.; Amesz, J.; Nozawa, Tsunenori

    1996-02-08

    Energy transfer and exciton coupling in isolated B800-850 complexes from the purple sulfur bacterium Chromatium tepidum were studied by means of spectrally resolved absorbance difference spectroscopy with a time resolution of 200 fs. Energy transfer from bacteriochlorophyll (BChl) 800 to BChl 850 was found to occur with a time constant of 0.8-0.9 ps. Remarkably, the amplitude of the absorbance changes of BChl 850 was 4 times larger than that of BChl 800. By relating this result to the crystal structure of B800-850 complexes of Rhodopseudomonas acidophila, it was concluded that the spectral properties of BChl 850 are mainly determined by strong exciton interactions between BChl 850 molecules in a circular symmetric arrangement, which lead to concentration of the oscillator strength in a few optically allowed transitions, corresponding to delocalized eigenstates. In BChl 850, a rapid red shift of the bleaching was observed. This relaxation process may be ascribed either to vibrational relaxation or exciton scattering. A similar red shift appears to occur in BChl 800. 26 refs., 5 figs.

  7. [Dominant phylotypes in the 16S rRNA gene clone libraries from bacterial mats of the Uzon caldera (Kamchatka, Russia) hydrothermal springs].

    PubMed

    Akimov, V N; Podosokorskaia, O A; Shliapnikov, M G; Gal'chenko, V F

    2013-01-01

    In situ analysis of the 16S rRNA genes form bacterial mats of five hydrothermal springs (36-58 degrees C) in the Uzon caldera (Kamchatka, Russia) was carried out using clone libraries. Eight clone libraries contained 18 dominant phylotypes (over 4-5%). In most clone libraries, the phylotype of the green sulfur bacterium Chlorobaculum sp. was among the dominant ones. The phylotypes of the green nonsulfur bacteria Chloroflexus and Roseiflexus and of purple nonsulfur bacteria Rhodoblastus, Rhodopseudomonas, and Rhodoferax were also among the dominant ones. Cyanobacteria were represented by one dominant phylotype in a single spring. Among nonphototrophic bacteria, the dominant phylotypes belonged to Sulfyrihydrogenibium sp., Geothrixsp., Acidobacterium sp., Meiothermus sp., Thiomonas sp., Thiofaba sp., and Spirochaeta sp. Three phylotypes were not identified at the genus level. Most genera of phototrophic and nonphototrophic organisms corresponding to the phylotypes from Uzon hydrotherms have been previously revealed in the hydrotherms of volcanically active regions of America, Asia, and Europe. These results indicate predominance of bacterial mats carrying out anaerobic photosynthesis in the hydrotherms of the Uzon caldera.

  8. Use of mixed culture bacteria for photofermentive hydrogen of dark fermentation effluent.

    PubMed

    Tawfik, Ahmed; El-Bery, Haitham; Kumari, Sheena; Bux, Faizal

    2014-09-01

    Hydrogen production (HP) from dark fermentation effluent of starch wastewater via vertical tubular photo-bioreactor was investigated. The reactor was inoculated with mixed culture of bacteria and operated at light intensity of 190 W/m(2). Hydraulic retention time (HRT) and organic loading rate (OLR) was varied between 0.9 to 4.0 h and 3.2 to 16 g COD/l.d., respectively. Increasing the HRT from 0.9 to 2.5 h, significantly (P<0.05) increased HP from 1±0.04 to 3.05±0.19 l/d, respectively. However, minimal increase in HP occurred when increasing the HRT up to 4.0 h. The HP remained unaffected when increasing the OLR from 3.2 to 6.4 g COD/l.d. Further increase in the OLR up to 8.2 and 16 g COD/l.d., resulted in a drop in HP i.e. 0.96 and 0.19 l/d, respectively. Microbial community analysis of the reactor samples showed the presence and dominance of hydrogen producing purple non-sulfur phototrophic (PNS) bacterium, Rhodopseudomonas palustris in the reactor. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. A structural basis for electron transfer in bacterial photosynthesis

    SciTech Connect

    Norris, J.R.; DiMagno, T.J.; Angerhofer, A.; Chang, C.H.; El-Kabbani, O.; Schiffer, M.

    1989-01-01

    Triplet data for the primary donor in single crystals of bacterial reaction centers of Rhodobacter sphaeroides and Rhodopseudomonas viridis are interpreted in terms of the corresponding x-ray structures. The analysis of electron paramagnetic resonance data from single crystals (triplet zero field splitting and cation and triplet linewidth of the primary special pair donor of bacterial reaction centers) is extended to systems of a non-crystalline nature. A unified interpretation based on frontier molecular orbitals concludes that the special pair behaves like a supermolecule in all wild-type bacteria investigated here. However, in heterodimers of Rb. capsulatus (His/sup M200/ changed to Leu or Phe with the result that the M-half of the special pair is converted to bacteriopheophytin) the special pair possesses the EPR properties more appropriately described in terms of a monomer. In all cases the triplet state and cation EPR properties appear to be dominated by the highest occupied molecular orbitals. These conclusions derived from EPR experiments are supplemented by data from Stark spectroscopy of reaction centers from Rb. capsulatus. 41 refs., 3 tabs.

  10. Evolutionary implications of phylogenetic analyses of the gene transfer agent (GTA) of Rhodobacter capsulatus.

    PubMed

    Lang, Andrew S; Taylor, Terumi A; Beatty, J Thomas

    2002-11-01

    The gene transfer agent (GTA) of the a-proteobacterium Rhodobacter capsulatus is a cell-controlled genetic exchange vector. Genes that encode the GTA structure are clustered in a 15-kb region of the R. capsulatus chromosome, and some of these genes show sequence similarity to known bacteriophage head and tail genes. However, the production of GTA is controlled at the level of transcription by a cellular two-component signal transduction system. This paper describes homologues of both the GTA structural gene cluster and the GTA regulatory genes in the a-proteobacteria Rhodopseudomonas palustris, Rhodobacter sphaeroides, Caulobacter crescentus, Agrobacterium tumefaciens and Brucella melitensis. These sequences were used in a phylogenetic tree approach to examine the evolutionary relationships of selected GTA proteins to these homologues and (pro)phage proteins, which was compared to a 16S rRNA tree. The data indicate that a GTA-like element was present in a single progenitor of the extant species that contain both GTA structural cluster and regulatory gene homologues. The evolutionary relationships of GTA structural proteins to (pro)phage proteins indicated by the phylogenetic tree patterns suggest a predominantly vertical descent of GTA-like sequences in the a-proteobacteria and little past gene exchange with (pro)phages.

  11. Enhanced photo-H2 production of R. faecalis RLD-53 by separation of CO2 from reaction system.

    PubMed

    Liu, Bing-Feng; Ren, Nan-Qi; Ding, Jie; Xie, Guo-Jun; Cao, Guang-Li

    2009-02-01

    The effect of different gases, CO(2) concentration, and separation of CO(2) from reaction system on photo-fermentation H(2) production was investigated by batch culture in this study. Experimental results showed that different gases (Ar,N(2),CO(2), and air) as gas phase have obviously affected on photo-H(2) production and a high concentration of CO(2) can inhibit the growth and H(2) evolution of Rhodopseudomonas faecalis RLD-53. When CO(2) concentration at 5%, cell increased most rapidly the specific growth rate of 0.489 g/l/h and the specific growth rate fell to be 0.265 g/l/h when CO(2) concentration at 40%. However, the growth of RLD-53 at CO(2) concentration of 60-100% was almost completely inhibited. At CO(2) concentrations of 5% and 10%, the maximum H(2) yield was 2.54 and 2.59 mol-H(2)/mol acetate, respectively, and it was similar with the control (2.61 mol-H(2)/mol acetate). H(2) not produced when CO(2) concentration at 60-100%. In conclusion, separation of CO(2) from reaction system can stimulate H(2) production in the entire photo-H(2) production process and H(2) yield increased about 12.8-18.85% than the control.

  12. Endophytic bacteria in plant tissue culture: differences between easy- and difficult-to-propagate Prunus avium genotypes.

    PubMed

    Quambusch, Mona; Pirttilä, Anna Maria; Tejesvi, Mysore V; Winkelmann, Traud; Bartsch, Melanie

    2014-05-01

    The endophytic bacterial communities of six Prunus avium L. genotypes differing in their growth patterns during in vitro propagation were identified by culture-dependent and culture-independent methods. Five morphologically distinct isolates from tissue culture material were identified by 16S rDNA sequence analysis. To detect and analyze the uncultivable fraction of endophytic bacteria, a clone library was established from the amplified 16S rDNA of total plant extract. Bacterial diversity within the clone libraries was analyzed by amplified ribosomal rDNA restriction analysis and by sequencing a clone for each identified operational taxonomic unit. The most abundant bacterial group was Mycobacterium sp., which was identified in the clone libraries of all analyzed Prunus genotypes. Other dominant bacterial genera identified in the easy-to-propagate genotypes were Rhodopseudomonas sp. and Microbacterium sp. Thus, the community structures in the easy- and difficult-to-propagate cherry genotypes differed significantly. The bacterial genera, which were previously reported to have plant growth-promoting effects, were detected only in genotypes with high propagation success, indicating a possible positive impact of these bacteria on in vitro propagation of P. avium, which was proven in an inoculation experiment. © The Author 2014. Published by Oxford University Press. All rights reserved.

  13. Redox cycling of Fe(II) and Fe(III) in magnetite by Fe-metabolizing bacteria

    SciTech Connect

    Byrne, James; Klueglein, Nicole; Pearce, Carolyn I.; Rosso, Kevin M.; Appel, Erwin; Kappler, Andreas

    2015-03-26

    Despite the regular occurrence of both magnetite and iron-metabolizing bacteria in the same environments, it is currently unknown whether the iron(II) and iron(III) in magnetite can be cycled between different bacteria and whether or how magnetic properties are affected by this metabolic activity. We show through magnetic and spectroscopic measurements that the phototrophic Fe(II)-oxidizer Rhodopseudomonas palustris TIE-1 can oxidize solid-phase magnetite nanoparticles using light energy, leading to a decrease in the measured magnetic susceptibility (MS). This process likely occurs at the surface and is reversible in the dark by the Fe(III)-reducer Geobacter sulfurreducens resulting in an increase in MS. These results show that iron ions bound in highly crystalline mineral magnetite are bioavailable as electron stores and electron sinks under varying environmental conditions, making magnetite a potential “biogeobattery” during day/night cycles. These findings are relevant for environmental studies and reinforce the impact of microbial redox processes on the global iron cycle.

  14. Diazotroph-Bacterial Community Structure of Root Nodules Account for Two-Fold Differences in Plant Growth: Consequences for Global Biogeochemical Cycles

    NASA Astrophysics Data System (ADS)

    Williams, M. A.

    2016-12-01

    The bacterial communities that inhabit and function as mutualists in the nodules of soybean, a major worldwide crop, are a fundamental determinant of plant growth and global nitrogen and carbon cycles. Unfertilized soybean can derive up to 90% of its nitrogen through bacterial-driven diazotrophy. It was the goal of the research in this study to assess whether different bacterial taxa (e.g. Bradyrhizobia spp.) differ in their soybean growth supportive role, which could then feedback to alter global biogeochemical cycling. Using 16S rRNA and NifH genes, nodule bacterial communities were shown to vary across 9 different cultivars of soybean, and that the variation between cultivars were highly correlated to plant yield (97 to 188 bu/Ha) and nitrogen. The relative abundances of gene sequences associated with the closest taxonomic match (NCBI), indicated that several taxa were (r= 0.76) negatively (e.g. Bradyrhizobium sp Ec3.3) or (r= 0.84) positively (e.g. Bradyrhizobium elkanii WSM 2783) correlated with plant yield. Other non-Rhizobiaceae taxa, such as Rhodopseudomonas spp. were also prevalent and correlated with plant yield. Soybeans and other leguminous crops will become increasingly important part of world food production, soil fertility and global biogeochemical cycles with rising population and food demand. The study demonstrates the importance of plant-microbial feedbacks driving plant growth but also ramifications for global cycling of nitrogen and carbon.

  15. Heterologous production of caffeic acid from tyrosine in Escherichia coli.

    PubMed

    Rodrigues, J L; Araújo, R G; Prather, K L J; Kluskens, L D; Rodrigues, L R

    2015-04-01

    Caffeic acid is a plant secondary metabolite and its biological synthesis has attracted increased attention due to its beneficial effects on human health. In this study, Escherichia coli was engineered for the production of caffeic acid using tyrosine as the initial precursor of the pathway. The pathway design included tyrosine ammonia lyase (TAL) from Rhodotorula glutinis to convert tyrosine to p-coumaric acid and 4-coumarate 3-hydroxylase (C3H) from Saccharothrix espanaensis or cytochrome P450 CYP199A2 from Rhodopseudomonas palustris to convert p-coumaric acid to caffeic acid. The genes were codon-optimized and different combinations of plasmids were used to improve the titer of caffeic acid. TAL was able to efficiently convert 3mM of tyrosine to p-coumaric acid with the highest production obtained being 2.62mM (472mg/L). CYP199A2 exhibited higher catalytic activity towards p-coumaric acid than C3H. The highest caffeic acid production obtained using TAL and CYP199A2 and TAL and C3H was 1.56mM (280mg/L) and 1mM (180mg/L), respectively. This is the first study that shows caffeic acid production using CYP199A2 and tyrosine as the initial precursor. This study suggests the possibility of further producing more complex plant secondary metabolites like flavonoids and curcuminoids.

  16. Unravelling the carbon and sulphur metabolism in coastal soil ecosystems using comparative cultivation-independent genome-level characterisation of microbial communities.

    PubMed

    Yousuf, Basit; Kumar, Raghawendra; Mishra, Avinash; Jha, Bhavanath

    2014-01-01

    Bacterial autotrophy contributes significantly to the overall carbon balance, which stabilises atmospheric CO2 concentration and decelerates global warming. Little attention has been paid to different modes of carbon/sulphur metabolism mediated by autotrophic bacterial communities in terrestrial soil ecosystems. We studied these pathways by analysing the distribution and abundance of the diagnostic metabolic marker genes cbbM, apsA and soxB, which encode for ribulose-1,5-bisphosphate carboxylase/oxygenase, adenosine phosphosulphate reductase and sulphate thiohydrolase, respectively, among different contrasting soil types. Additionally, the abundance of community members was assessed by quantifying the gene copy numbers for 16S rRNA, cbbL, cbbM, apsA and soxB. Distinct compositional differences were observed among the clone libraries, which revealed a dominance of phylotypes associated with carbon and sulphur cycling, such as Gammaproteobacteria (Thiohalomonas, Allochromatium, Chromatium, Thiomicrospira) and Alphaproteobacteria (Rhodopseudomonas, Rhodovulum, Paracoccus). The rhizosphere soil was devoid of sulphur metabolism, as the soxB and apsA genes were not observed in the rhizosphere metagenome, which suggests the absence or inadequate representation of sulphur-oxidising bacteria. We hypothesise that the novel Gammaproteobacteria sulphur oxidisers might be actively involved in sulphur oxidation and inorganic carbon fixation, particularly in barren saline soil ecosystems, suggesting their significant putative ecological role and contribution to the soil carbon pool.

  17. Fahrzeug-Außengeräusch

    NASA Astrophysics Data System (ADS)

    Genuit, Klaus

    Wirtschaftliches Wachstum ist mit steigenden Anforderungen an Mobilität und Transport verknüpft. Zukunftsorientierter Fortschritt muss hierbei die Wirkungen von Verkehrsgeräuschen auf Mensch und Umwelt berücksichtigen, um eine hohe Lebensqualität sicherstellen zu können. Mehr als die Hälfte der Bevölkerung in der EU fühlt sich durch Verkehrslärm belästigt oder befürchtet direkte Auswirkungen auf Gesundheit und Wohlbefinden. Nach einer repräsentativen Umfrage des Umweltbundesamtes fühlen sich durch Straßenverkehrslärm 20 % der Bevölkerung stark oder wesentlich belästigt (UBA 2008). Daher ist das "Fahrzeug-Außengeräusch“ Gegenstand zahlreicher Forschungsprojekte zu Themen wie Identifikation wesentlicher Geräuschquellen, Zusammenhang zwischen Verkehrsgeräusch und Belästigung, medizinische Folgen aufgrund chronischer Lärmexposition, Geräuschqualität, Entwicklung neuer Methoden und Technologien zur Fahrzeug-Außengeräuschmessung und das Fahrzeug-Außengeräusch als wesentliches Produktattribut, das aktiver Gestaltung bedarf.

  18. 1D-Messungen physiologischer Bewegungen am Hals mit optischer Kohärenztomographie

    NASA Astrophysics Data System (ADS)

    Dämgen, M.; Schwab, B.; Lenarz, Th.; Leinung, M.

    In der Chirurgie insbesondere bei onkologischen Fragestellungen kommt es zu Grenzsituationen, in denen es gilt, Gewebeverbände mit hoher Genauigkeit aufzutrennen, z.B. bei Infiltration von Gefäßwänden oder Nervenstrukturen durch Tumorausläufer. Oft könnte eine physiologisch funktioneil wichtige Struktur erhalten werden, wenn ein chirurgisches Instrument existierte, das mit einer überaus hohen Präszision arbeitet. Hierfür ist ein (ultra-)kurzgepulster Laser geeignet, der bei kleinem Focus und minimalen thermischen Wechselwirkungen lediglich vernachlässigbare Kollateralschäden im umgebenden Gewebe erzeugt. Allerdings ist ein solches System nicht mehr allein durch den Operateur kontrollierbar. Daher wurde die Idee entwickelt, ein automatisiertes Assistenzsystem zu designen, das mit einem in entsprechender Genauigkeit arbeitenden Sensor (optische Kohärenztumographie, OCT) und einem Femtosekunden(fs)-Laser als Aktor teilautonom kritische Schritte des operativen Eingriffs unter der Kontrolle des Operateurs vornimmt. Die Vorbedingung eines solchen Systemes jedoch ist die Anpassung an physiologische Bewegungen im OP-Gebiet. Zur Messpooletablierung müssen diese physiologischen Bewegungen aufgezeichnet werden mit der den Dimensionen erforderlichen Präzision.

  19. Radioaktive Biomaterialien

    NASA Astrophysics Data System (ADS)

    Assmann, Walter

    In der Strahlentherapie von Tumorgewebe (Radioonkologie) nutzt man die zellschädigende Wirkung verschiedener Strahlenarten zur gezielten Abtötung der Tumorzellen. Um bei der perkutanen Bestrahlung die Strahlenschäden im gesunden Gewebe in Grenzen zu halten, wird der Tumor aus verschiedenen Richtungen mit gut fokussiertem Strahl behandelt. Moderne Bestrahlungsanlagen sind durch Steuerung über leistungsfähige Rechner in der Lage, ein millimetergenaues Bestrahlungsprogramm abzufahren, das individuell auf den jeweiligen Tumor abgestimmt ist. Ein ganz anderer Weg, das umgebende gesunde Gewebe zu schonen, wird in der sog. Brachytherapie beschritten. Hier wird ein kurzreichweitiger, radioaktiver Strahler entweder direkt in das Tumorgewebe (interstitiell) oder in grosser Nähe (intrakavitär) permanent oder nur für eine bestimmte Zeitdauer eingebracht. Ein Beispiel ist die Behandlung des Prostatakarzinoms durch die Implantation von dünnwandigen metallischen Hülsen (seeds) von nur wenigen Millimetern Länge und knapp einem Millimeter Durchmesser, die minimalinvasiv mittels feiner Kanülen in die Prostata eingebracht werden. Sie enthalten ein künstliches Radionuklid mit typisch einigen Wochen Halbwertszeit, dessen therapeutisch wirksame Strahlungsdosis sich auf wenige Millimeter des umgebenden Gewebes beschränkt. Wesentlich für den Erfolg einer Strahlentherapie mit derartig kurzreichweitigen Strahlern ist eine Lagekontrolle mit entsprechend hoher räumlicher Auflösung.

  20. Schönheit und andere Provokationen - Eine neue evolutionsbiologische Theorie der Kunst

    NASA Astrophysics Data System (ADS)

    Junker, Thomas

    Die Evolution hat viele spektakuläre Phänomene hervorgebracht - von der Eleganz des Vogelflugs über die gigantischen Körper der Dinosaurier und die farbenprächtige Vielfalt der Korallenriffe bis hin zu ihrem jüngsten Geniestreich - der menschlichen Kunst. Die schönen Künste - Malerei, Bildhauerei und Architektur, Theater, Tanz, Oper und Filmkunst, Musik und Literatur - Produkte der Evolution? Diese Vorstellung mutet vielen Menschen fremd an, aber wie könnte es anders sein? Denn wenn Charles Darwin recht hat, dann sind nicht nur die körperlichen Merkmale der Menschen als Antworten auf die Erfordernisse des Lebens entstanden, sondern auch ihre geistigen Fähigkeiten und Verhaltensweisen. Im Jahr 1859 hatte er auf den letzten Seiten seines berühmten Buches über die Entstehung der Arten eine kühne Prophezeiung gemacht: Durch die Evolutionstheorie werde es "zu einer bemerkenswerten Revolution in der Naturwissenschaft kommen […]. Die Psychologie wird auf die neue Grundlage gestellt, dass jede geistige Kraft und Fähigkeit notwendigerweise durch graduelle Übergänge erworben wird“ (Darwin 1859, S. 484, 488; Junker 2008).

  1. [The mental health of only children and of siblings with cancer - first results of a multicenter study in Germany].

    PubMed

    Bojanowski, Sabine; Führer, Daniel; Romer, Georg; Bergelt, Corinna; von Klitzing, Kai; Brähler, Elmar; Keller, Monika; Resch, Franz; Flechtner, Hans-Henning; Lehmkuhl, Ulrike; Weschenfelder-Stachwitz, Heike

    2014-07-01

    Theoretischer Hintergrund: Kinder krebskranker Eltern wurden als Risikogruppe für die Entwicklung von psychischen Störungen identifiziert. Ergebnisse der Scheidungsforschung zeigten, dass auch Geschwisterbeziehungen bei belastenden Lebensereignissen vor psychischen Störungen schützen können. Fragestellung: Kann das Vorhandensein eines Geschwisters die Bewältigung einer elterlichen onkologischen Erkrankung unterstützen und somit auch dort als protektiver Faktor wirken? Methodik: In einer multizentrischen Studie wurden 271 Kinder untersucht. 54 % waren Inanspruchnehmer eines psychosozialen Beratungsangebotes. Einzelkinder (N = 89) und Kinder mit Geschwistern (N = 182) wurden im Hinblick auf ihre psychische Belastung (Strength and Difficulties Questionnaire, SDQ, Selbst- und Fremdurteil) miteinander verglichen. Ergebnisse: Im Gruppenvergleich zeigten sich zwischen Einzelkindern und Kindern mit Geschwistern keine signifikanten Unterschiede im Gesamturteil der Eltern. Dies galt sowohl für die Einschätzung durch den gesunden als auch durch den erkrankten Elternteil. In der Selbsteinschätzung zeigten sich bei 2 % der Einzelkinder und bei 9 % der Geschwister klinisch auffällige Werte im Gesamtproblemwert des SDQ. Der Gruppenvergleich zwischen Einzelkindern und Kindern mit Geschwistern offenbarte im Hinblick auf deren psychische Belastung keine bedeutsamen Unterschiede. Es ergaben sich Hinweise darauf, dass eine negative Beziehungsqualität (Sibling Relationship Questionnaire, SRQ) mit verstärkten Problemen in der Peer-Group assoziiert ist. Schlussfolgerungen: Das Vorhandensein eines Geschwisters ist nicht per se ein protektiver Faktor. Einzelkinder wiesen im Vergleich zu Kindern mit Geschwistern keine höhere psychische Belastung auf.

  2. Kooperative Automation

    NASA Astrophysics Data System (ADS)

    Hakuli, Stephan; Bruder, Ralph; Flemisch, Frank O.; Löper, Christian; Rausch, Herbert; Schreiber, Michael; Winner, Hermann

    Das Aufgabenspektrum moderner Assistenzsyseme erstreckt sich von der Steigerung des Fahrkomforts bis hin zur Übernahme aktiver Sicherheitsfunktionen. Selbst komplexe Systeme wie die adaptive Fahrgeschwindigkeitsregelung ACC (Adaptive Cruise Control, vgl. Kap. 32), die wie viele weitere Innovationen in der Fahrzeugindustrie einst der automobilen Oberklasse vorbehalten war, dringen derzeit über die Mittelklasse in den Massenmarkt vor und beginnen, die Öffentlichkeit für die mit hoher Automatisierung einhergehenden Veränderungen und Herausforderungen zu sensibilisieren. Denn so beeindruckend die Leistungsfähigkeit moderner Fahrerassistenzsysteme auch ist, so verursacht sie doch ein Dilemma: Mit der Übernahme von primären Fahraufgaben durch Fahrerassistenzsysteme werden vom Fahrer neue und erweiterte Bedienfähigkeiten erwartet. Zum einen muss er ein mentales Modell eines jeden vorhandenen Assistenzsystems mit dessen spezifscher Mensch-Maschine-Schnittstelle aufbauen und dessen funktionale Grenzen verinnerlichen. Zum anderen muss er, nachdem er einen Teil seiner Fahraufgabe an ein Assistenzsystem übertragen hat, die (teil-)automatisierte Funktion überwachen, die Handlungen des Systems antizipieren und eine permanente Bereitschaft zur Rückübernahme der durch die Assistenzfunktion ausgeführten Fahraufgabe aufweisen. Die Rückübernahme geschieht entweder willentlich, wenn die Unterstützung nicht nach des Fahrers Vorstellung verläuft, oder sie ist obligatorisch, wenn die Assistenzfunktion an ihre funktionalen Grenzen stößt und explizit zur Übernahme auffordert.

  3. Berlin in Motion: Interprofessional teaching and learning for students in the fields of medicine, occupational therapy, physiotherapy and nursing (INTER-M-E-P-P).

    PubMed

    Bohrer, Annerose; Heinze, Cornelia; Höppner, Heidi; Behrend, Ronja; Czakert, Judith; Hitzblech, Tanja; Kaufmann, Ina; Maaz, Asja; Räbiger, Jutta; Peters, Harm

    2016-01-01

    Zielsetzung: Das Berliner Projekt „Interprofessionelles Lehren und Lernen in Medizin, Ergotherapie, Physiotherapie und Pflege“ (INTER-M-E-P-P) verfolgt das Ziel, interprofessionelle Lehrveranstaltungen modellhaft zu entwickeln, zu erproben und in die Curricula der Studiengänge zu implementieren. Methodik: Unter der Leitung einer institutions-, professions- und statusübergreifenden Lenkungsgruppe werden interprofessionelle Lehrveranstaltungen konzipiert, durchgeführt und evaluiert. Spezifisch sind die studentische Partizipation in der Lenkungsgruppe und die Begleitung durch externe Supervision. Die Evaluation integriert die Perspektiven aller am Projekt Beteiligten und kombiniert qualitative und quantitative Methoden. Ergebnisse: INTER-M-E-P-P hat Strukturen zur Kooperation der beteiligten Hochschulen und Studiengänge aufgebaut. Drei Lehrveranstaltungen wurden interprofessionell konzipiert, durchgeführt und evaluiert. Die unterschiedliche curriculare, strukturelle und räumliche Verortung der Studiengänge führt zu einem hohen, ressourcenintensiven Planungs- und Umsetzungsaufwand. Stereotype und Rollenbilder der Planenden können den Prozess erschweren; unter externer Supervision jedoch die professionsspezifischen Blickwinkel erweitern und bereichern.Schlussfolgerung: Eine nachhaltige Implementierung von IPL in die Curricula der Gesundheitsstudiengänge ist derzeit durch Barrieren wie die räumliche Trennung und verschiedene Studien- und Prüfungsordnungen erschwert. Sie benötigt dauerhafte Unterstützungsstrukturen auf hochschulischer und politischer Ebene.

  4. Exoprothetik

    NASA Astrophysics Data System (ADS)

    Blumentritt, Siegmar; Milde, Lothar

    Exoprothesen sind orthopädische Hilfsmittel, die als Körperersatzstücke dem funktionellen und ästhetisch-kosmetischen Ausgleich von amputierten oder von Geburt an fehlenden Gliedmaßenabschnitten dienen. Durch die Amputation wird ein Teil einer Gliedmaße im knöchernen Bereich oder im Gelenk abgetrennt. Die Indikationsstellung zur Amputation ist eine höchst verantwortungsvolle und schwierige ärztliche Entscheidung, weil sie die körperliche, seelische und soziale Integrität des betroffenen Menschen unwiderruflich nachhaltig beeinträchtigt. Unmittelbar mit der Indikationsstellung ist die individuell bedingte Festlegung der Amputationshöhe verbunden. Die Indikation und die Wahl der Amputationshöhe determinieren bereits wesentlich den Rehabilitationsverlauf. Die Rehabilitation Amputierter gelingt am besten im erfahrenen interdisziplinären Rehabilitationsteam, dessen Handeln letztlich auf die eigenbestimmte und gleichberechtigte Teilhabe der so behinderten Menschen am gesellschaftlichen Leben gerichtet ist. Dies schließt die ganzheitliche Betrachtung der Patientensituation durch das interdisziplinäre Rehabilitationsteam zur individuellen Prothesenversorgung ein, mit der die technischen Möglichkeiten für das angestrebte Therapieziel geklärt werden.

  5. Veränderungen der Funktion und Organisation von Logistikdienstleistern in Warenketten

    NASA Astrophysics Data System (ADS)

    Kulke, Elmar; Henschel, Sven

    Die Veränderung von ökonomischen Rahmenbedingungen und Anforderungen - z.B. durch post-fordistische Unternehmensstrukturen, veränderte Güterstrukturen, internationale Liberalisierungen - sowie interne Organisationsinnovationen führten zu erheblichen Veränderungen bei den Logistikdienstleistern. Es entstanden große Logistikunternehmen, die vielfältige Zusatzaufgaben neben dem Transport von Waren übernehmen; sie organisieren oftmals die komplette Warenkette und setzen dazu immer intensiver IKT ein. Parallel zur physischen Warenkette sind IKT-basierte Informationsketten entstanden. Diese sind aber in Segmente mit starkem Informationsfluss (z.B. in einem Logistikunternehmen) und in Schnittstellen mit schwächerem Informationsfluss (z.B. zu anderen Einheiten) gegliedert. Auch liefern die neuen IKT oftmals mehr Informationen, als tatsächlich genutzt werden. Die Rahmenbedingungen führen zu eher steigenden Transportvorgängen und Wegedistanzen; die neuen IKT schwächen den Anstieg durch Bündelungen und Wegeoptimierungen etwas ab; der limitierte Zugang zu Informationen stärkt den Bedeutungsgewinn großer Logistikdienstleister.

  6. > Einleitung

    NASA Astrophysics Data System (ADS)

    Spath, Dieter; Pischetsrieder, Bernd

    Rund 40 Prozent aller Fahrzeuge fahren elektrisch. Ein Zustand, der aus heutiger Sicht noch in weiter Ferne liegt, war vor über 100 Jahren bereits Realität. Um 1900, einige Jahre nach der Erfindung des Automobils, wurden Fahrzeuge durch unterschiedliche Antriebskonzepte angetrieben. Die drei wichtigsten waren Dampfantrieb, Elektroantrieb und der Benzinmotor. Durch die überlegene Energiedichte und eine kostengünstige sowie scheinbar unendliche Verfügbarkeit des Energieträgers Öl entwickelte sich der Verbrennungsmotor zum dominanten Antriebskonzept. Der Einsatz von Elektrofahrzeugen beschränkte sich im Verlauf des 20. Jahrhunderts auf wenige Nischenanwendungen. Der verbrennungsmotorbasierte Antriebsstrang ist dem Elektroantrieb auch heute noch technisch und ökonomisch überlegen. Die Randbedingungen ändern sich jedoch. Die Verknappung des fossilen Brennstoffs Öl und die stetige Verschärfung der CO2-Emissionsziele in Verbindung mit einer starken Zunahme individueller Mobilität im asiatischen Raum und vielen weiteren Regionen der Welt stellen den Verbrennungsmotors als die dominante Antriebstechnologie in Frage. Trotz des Optimierungspotentials, welches auch nach über 120-jähriger Entwicklung noch im Verbrennungsmotor liegt, ist diese Technologie immer mit lokalen Schadstoff- und Lärmemissionen verbunden. Die Notwendigkeit der Reduktion von Treibhausgasen verbunden mit einem steigenden Urbanisierungsgrad wird in Zukunft einen Technologiewechsel vom Verbrennungsmotor zum elektrischen Antrieb attraktiv machen. Dieser Technologiewechsel bedeutet jedoch weit mehr als das Austauschen des Antriebsstranges, Elektromobilität ist ein komplexes Themengebiet mit unterschiedlichen Dimensionen.

  7. On the history of plasma treatment and comparison of microbiostatic efficacy of a historical high-frequency plasma device with two modern devices.

    PubMed

    Napp, Judith; Daeschlein, Georg; Napp, Matthias; von Podewils, Sebastian; Gümbel, Denis; Spitzmueller, Romy; Fornaciari, Paolo; Hinz, Peter; Jünger, Michael

    2015-01-01

    Hintergrund: Kaltes Atmosphärendruckplasma (CAP) hat durch seine mannigfaltigen bioaktiven Eigenschaften ein neues medizinisches Feld definiert: die Plasmamedizin. Allerdings wurde vor etwa 100 Jahren CAP in verwandter Form in der Hochfrequenztherapie genutzt. Zielsetzung dieser Studie war eine Übersicht über die historischen Plasmabehandlungen zu gewinnen und Daten bezüglich der antimikrobiellen Wirkung eines historischen Hochfrequenzapparats zu gewinnen.Methode: Erstens wurde historische Literatur bezüglich CAP-Behandlungen ausgewertet, da aus dem heutigen Schrifttum keine Angaben gewonnen werden konnten. Zweitens wurde die Empfindlichkeit von fünf verschiedenen bakteriellen Wundisolaten auf Agar gegenüber einer historischen Plasmaquelle (violet wand [VW]) und zwei modernen Geräten (atmospheric pressure plasma jet [APPJ] und Dielectric Barrier Discharge [DBD]) ermittelt. Die erzielten Hemmhöfe wurde verglichen. Ergebnisse: Die seinerzeit populärsten elektromedizinischen Anwendungen erzeugten durch Glaselektroden sogenannte Effluvien, die mit modernem CAP verwandt sind. Alle drei untersuchten Plasmaquellen zeigten eine vollständige Eradikation aller behandelter Isolate im plasmabehandelten Bereich. Die historische Plasmaquelle (VW) war dabei ähnlich wirksam wie die modernen Plasmaquellen. Schlussfolgerung: In begrenztem Umfang kann retrograd ein Wirksamkeitsnachweis der historischen Plasmabehandlungen abgeleitet werden, insbesondere bei der Behandlung infektiöser Erkrankungen. Die zugrunde liegende Technologie könnte für die Entwicklung moderner Nachfolgegeräte genutzt werden.

  8. [Is it beneficial to involve family member? A literature review to psychosocial interventions in family-centered nursing].

    PubMed

    Mahrer-Imhof, Romy; Bruylands, Michelle

    2014-10-01

    Hintergrund: Familien haben Einfluss auf die Gesundheit von chronisch erkrankten Patientinnen und Patienten und werden durch die Krankheit selbst in ihrem Wohlbefinden beeinflusst. Familienmitglieder in die Pflege einzubeziehen, wurde in verschiedenen Studien getestet. Ziel: Das Ziel dieser Literaturübersicht war, randomisiert kontrollierte Studien und Metaanalysen zu familienzentrierten Interventionen (FI) auf die Ergebniskriterien und Effektgrößen der Veränderungen zu untersuchen. Methode: Drei Metaanalysen für den Zeitraum bis 2007 und sechs randomisierte kontrollierte Studien ab 2007 zu psychosozialen familienzentrierten Interventionen wurden eingeschlossen. Ergebnisse: Die Studien zeigten, dass FI kleine bis mittlere positive Effekte auf Depression, psychische Gesundheit, Angst von Patienten und Angehörigen sowie auf die Belastung der Angehörigen hatten. Der Effekt auf physische Gesundheitsparameter konnte nicht gezeigt werden. Die Ergebnisse hingen von der untersuchten Population, den Teilnehmenden an der FI, der Art und dem Zeitraum und der Zeitdauer (Dosis) der FI ab. Die Studien zeigten große Unterschiede in der Länge und Art der Intervention, der Zielpopulation und der Auswahl der Ergebniskriterien sowohl für Patienten als auch für Angehörige. Vergleiche der Ergebnisse sind erschwert durch die Verwendung unterschiedlichster Messinstrumente. Schlussfolgerungen: Weitere Forschung mit verschiedenen Populationen, unterschiedlicher Ausprägung der FI, aber unter Verwendung der gleichen validen Messinstrumente ist anzustreben.

  9. Blutpräparate und therapeutische Anwendung (Hämotherapie)

    NASA Astrophysics Data System (ADS)

    Burkhart, Jürgen; Leimbach, Rainer; Nagl, Detlev; Weinauer, Franz

    Die Geschichte der Blutübertragung lässt sich bis in das Altertum verfolgen - wenn auch hier das Blut nicht in die Blutgefäße eingebracht, sondern als Trank verabreicht wurde. Im alten Rom stürmten die Zuschauer in die Kampfarena, um das Blut verletzter Gladiatoren zu trinken, in dem Gedanken, deren Stärke würde in sie überfließen. So wurden auch Greise mit dem Blut von Jünglingen behandelt. Der Glaube, mit dem Blut würden Eigenschaften des Spenders übertragen, muss wohl auch bei dem Versuch mitgewirkt haben, Verbrecher durch Übertragung von Schafsblut "lammfromm“ zu machen. Zu Beginn der Mensch-zu-Mensch-Übertragung wurde Blut mittels eines Röhrchens von Blutgefäß zu Blutgefäß transfundiert. Diese im Mittelalter neu erprobte Form basierte auf der Entdeckung des Blutkreislaufes durch William Harvey (1578-1657). Es überwog allerdings noch die Blutübertragung vom Tier auf den Menschen, die nicht selten mit dem Tod beider Beteiligter endete. In der aufklärerischen Phase der französischen Revolution wurde diese Art der Blutübertragung deshalb verboten.

  10. Herstellung eines federelastischen Spangutes geringer Dichte als Matrix für Schüttdämmstoffe, für plattenförmige Dämmstoffe und leichte Spanplatten

    NASA Astrophysics Data System (ADS)

    Tröger, Johannes; Groß, Lucia

    Klimaschutz und die ständig steigenden Energiekosten erfordern eine kontinuierliche Verbesserung der Dämmstoffe. Eine Alternative zur relativ kostenaufwändigen Wärmedämmung durch Platten bzw. Matten auf Basis von mineralischen Stoffen, ist der Einsatz von schütt-bzw. einblasbaren Dämmstoffpartikeln. Späne aus Holz und andere Dämmstoffe aus nachwachsenden Rohstoffen waren schon vor dem ersten Weltkrieg die gebräuchlichsten Dämmstoffe überhaupt. Seit etwa fünfzehn Jahren werden u.a. für den Holzhausbau im zunehmenden Maße auch Fräs-, Säge und Hobelspäne für Wärmedämmzwecke eingesetzt [1], [2], [3]. Hervorzuheben ist der ökologische Aspekt dieser Dämmstoffe durch die Bindung von CO2 und den sinkenden Heizenergiebedarf. Die bisherige Philosophie bei der Gewinnung von Dämmstoffspänen beruhte darauf, anfallendes Spangut stofflich weiter zu nutzen. Die Recyclingspäne sollten dabei sowohl die Setzungssicherheit als auch eine möglichst gute Wärmedämmung gewährleisten.

  11. Microbial contamination of mobile phones in a health care setting in Alexandria, Egypt.

    PubMed

    Selim, Heba Sayed; Abaza, Amani Farouk

    2015-01-01

    Zielsetzung: Es sollte die mikrobielle Kontamination von Mobiltelefonen in einer universitären Gesundheitseinrichtung untersucht werden.Methode: Abstrichproben wurden von 40 Mobiltelefonen von Patienten und Mitarbeitern im Universitätskrankenhaus in Alexandria entnommen. Die mikrobiologische Analyse wurde im mikrobiologischen Labor des Instituts für Public Health durchgeführt. Die Quantifizierung erfolgte sowohl durch direkte Ausbringung auf die Platte als auch durch Anlage von Subkulturen zur Differenzierung. Methicillin-resistente Staphylococcus aureus (MRSA) wurden mittels Plättchendiffusionsmethode nach Bauer und Kirby identifiziert. Isolierte Gram-negative Organismen wurden auf Vorkommen von ESBL-Bildung mittels der Doppeldiffusionsmethode gemäß Empfehlung des Clinical and Laboratory Standards Institute untersucht.Ergebnisse: Alle untersuchten Mobiltelefone waren entweder mit einer oder mehreren bakteriellen Arten kontaminiert. Am häufigsten wurden MRSA (53%) und Koagulase-negative Staphylokokken (50%) nachgewiesen. Als mittlere Anzahl von KbE ergaben sich 357 KbE mit einem Median von130 KbE/ml pro Mobiltelefon im Plattengussverfahren. Die korrespondierenden Werte betrugen 2.192 bzw. 1.720 KbE/Mobiltelefon im Direktausstrich.Schlussfolgerung: Mobiltelefone stellen ein Risiko in Gesundheitseinrichtungen zur Weiterverbreitung nosokomialer Pathogen einschließlich MRSA dar. Auf der Oberfläche von Mobiltelefonen kann die mikrobielle Kontamination methodisch einfach nachgewiesen werden.

  12. Retrospective analysis of a VACM (vacuum-assisted closure and mesh-mediated fascial traction) treatment manual for temporary abdominal wall closure - results of 58 consecutive patients.

    PubMed

    Beltzer, Christian; Eisenächer, Alexander; Badendieck, Steffen; Doll, Dietrich; Küper, Markus; Lenz, Stefan; Krapohl, Björn Dirk

    2016-01-01

    Einleitung: Das optimale Behandlungskonzept eines temporären Bauchdeckenverschlusses (temporary abdominal closure, TAC) bei kritisch kranken viszeralchirurgischen Patienten mit offenem Abdomen („open abdomen“, OA) ist weiterhin unklar. Durch eine VACM-Therapie (vacuum-assisted closure and mesh-mediated fascial traction) scheinen sich gegenüber anderen Verfahren des TAC höhere Faszienverschlussraten (delayed primary fascial closure rate, FCR) realisieren zu lassen. Material und Methoden: Patienten unserer Klinik (n=58), welche in den Jahren 2005 bis 2008 mittels eines VAC/VACM-Behandlungsmanuals behandelt wurden, wurden retrospektiv analysiert. Ergebnisse: Die FCR aller Patienten betrug insgesamt 48,3% (95%-Konfidenzintervall: 34,95–61,78). Bei Patienten, bei denen im Verlauf ein Vicryl-Netz auf Faszienebene implantiert wurde (VACM-Therapie), konnte eine FCR von 61,3% realisiert werden. Die Letalität der mittels VACM therapierten Patienten betrug 45,2% (95%-KI: 27,32–63,97).Schlussfolgerung: Die Ergebnisse der eigenen Untersuchung bestätigen bisherige Studienergebnisse, die eine akzeptable FCR bei non-trauma-Patienten durch Anwendung der VACM-Therapie zeigen konnten. Die VACM-Therapie scheint aktuell Therapiekonzept der ersten Wahl bei Patienten mit OA und Indikation zum TAC zu sein.

  13. Wie wissenschaftlich ist der Evolutionsgedanke?

    NASA Astrophysics Data System (ADS)

    Vollmer, Gerhard

    Darwin war ein besonnener Mann; alles Aufsehen war ihm zuwider. Trotzdem hat er eine Revolution ausgelöst, deren Wirkung nicht auf die Biologie beschränkt blieb. Seine Theorie lässt sich in fünf Teiltheorien zerlegen, die sich durch die Begriffe Artenwandel, Verwandtschaft alles Lebendigen und gemeinsamer Ursprung, Artenaufspaltung und Artenvielfalt, Gradualismus, natürliche Auslese charakterisieren lassen. Dadurch wurden mehrere religiöse und weitere weltanschauliche Überzeugungen in Frage gestellt. Deshalb wird die Evolutionstheorie auch heute noch vielfach kritisiert, ja bekämpft. Die Vorwürfe lassen sich ordnen nach den Kriterien, mit denen wir erfahrungswissenschaftliche Theorien beurteilen. Haltbar ist daran nur, dass es für die Evolutionstheorie zwar beliebig viele Bestätigungen gibt, aber nur wenige Widerlegungsmöglichkeiten. Durch die neuerdings entwickelten und durchgeführten Evolutionsexperimente ist die empirische Situation allerdings deutlich besser geworden. Am (erfahrungs)wissenschaftlichen Charakter der Evolutionstheorie besteht deshalb kein Zweifel.

  14. Identifikationsverfahren zur Analyse von EEG-Signalen bei Epilepsie mit Reaktions-Diffusions Netzwerken

    NASA Astrophysics Data System (ADS)

    Gollas, F.; Tetzlaff, R.

    2007-06-01

    Partielle Differentialgleichungen des Reaktions-Diffusions-Typs beschreiben Phänomene wie Musterbildung, nichtlineare Wellenausbreitung und deterministisches Chaos und werden oft zur Untersuchung komplexer Vorgänge auf den Gebieten der Biologie, Chemie und Physik herangezogen. Zellulare Nichtlineare Netzwerke (CNN) sind eine räumliche Anordnung vergleichsweise einfacher dynamischer Systeme, die eine lokale Kopplung untereinander aufweisen. Durch eine Diskretisierung der Ortsvariablen können Reaktions-Diffusions-Gleichungen häufig auf CNN mit nichtlinearen Gewichtsfunktionen abgebildet werden. Die resultierenden Reaktions-Diffusions-CNN (RD-CNN) weisen dann in ihrer Dynamik näherungsweise gleiches Verhalten wie die zugrunde gelegten Reaktions-Diffusions-Systeme auf. Werden RD-CNN zur Identifikation neuronaler Strukturen anhand von EEG-Signalen herangezogen, so besteht die Möglichkeit festzustellen, ob das gefundene Netzwerk lokale Aktivität aufweist. Die von Chua eingeführte Theorie der lokalen Aktivität Chua (1998); Dogaru und Chua (1998) liefert eine notwendige Bedingung für das Auftreten von emergentem Verhalten in zellularen Netzwerken. Änderungen in den Parametern bestimmter RD-CNN könnten auf bevorstehende epileptische Anfälle hinweisen. In diesem Beitrag steht die Identifikation neuronaler Strukturen anhand von EEG-Signalen durch Reaktions-Diffusions-Netzwerke im Vordergrund der dargestellten Untersuchungen. In der Ergebnisdiskussion wird insbesondere auch die Frage nach einer geeigneten Netzwerkstruktur mit minimaler Komplexität behandelt.

  15. Use of elaborate feedback and an audience-response-system in dental education.

    PubMed

    Rahman, Alexander; Jacker-Guhr, Silke; Staufenbiel, Ingmar; Meyer, Karen; Zupanic, Michaela; Hahnemann, Merle; Lührs, Anne-Katrin; Eberhard, Jörg

    2013-01-01

    Einleitung: Die Studie soll die Frage klären, ob sich durch Anwendung von elaboriertem Feedback und einem Audience-Response-Systems (ARS) der Lernerfolg im Studienfach Zahnerhaltung signifikant verbessert. Methodik: Die Studierenden des 1. klinischen Semesters wurden in eine Studien- und eine Kontrollgruppe randomisiert eingeteilt. Die Randomisierung erfolgte unter Berücksichtigung der Faktoren Alter, Geschlecht und Note im Physikum. Im Verlauf von 10 Vorlesungen wurden pro Vorlesung 5 Multiple-Choice-Fragen zu den formulierten Lernzielen gestellt. Diese wurden unter Anwendung eines ARS von den Studierenden beantwortet. Nur die Studiengruppe erhielt sofort ein elaboriertes Feedback zu den Ergebnissen. Die am Ende durchgeführte Abschlussklausur und Evaluation sollten ermitteln, ob das elaborierte Feedback zu einem Lernerfolg führt und welchen Effekt das ARS auf die Vorlesungsatmosphäre hat. Ergebnisse: Die Ergebnisse der Abschlussklausuren ergaben keinen signifikanten Unterschied zwischen dem Lernerfolg der Studien- und der Kontrollgruppe. Schlussfolgerung: Durch das elaborierte Feedback zeigte sich in dieser Untersuchung kein Unterschied im Lernerfolg. Mit dem ARS ließ sich jedoch eine interaktivere, positivere Lernatmosphäre schaffen.

  16. Welt und Wirkungsprinzip (2nd Aufl.)

    NASA Astrophysics Data System (ADS)

    Landgraf, Werner

    2010-03-01

    Modell einer kausalen Bewirkung der Welt, und logische, geometrische, physikalische Interprätation dieser Kausalmenge und Fortwirkung der frühsten ihrer sukzessiv als echt Neues bewirkten und durch Vorhandenes oder Späteres nicht darstellbaren oder widerrufbaren Ereignisse als Dimensionen und sie verkörpernde primäre Naturkräfte, mit Korrespondenz zur beobachteten Welt und ihrer grundlegendsten Eigenschaften. Wirklich ist nur was wirkt, wo und wie. Entsprechend ist im Bogenelement statt der Eigenzeit die variante Anzahl Wirkungen relevant, 0 ≈ 1/h2 dS2 - 1/tpl2 (dt2 - 1/c2 {dq12 + G02/G2 [dq2,32 - ...]}) mit G0 = c4lpl/Epl ≈ G. Die heutigen Dimensionen und Naturkräfte entstanden in dieser Reihenfolge, haben 'komplementäre' aber gleichwertige statische und dynamische Aspekte, entsprechend ihren Termen in Bogenelement bzw. Vierervektor, aus derem Vergleich sowie mit denen ihrer Nachbarn folgen Grundgleichungen bzw. Erhaltungssätze. Jeweils individuelle Eigenschaften wie ihre Naturkonstante konkretisieren sie und tragen zu gattungsmäßigen wie globale Affinität und Äquivalenzen bei. Ältestes Gebiet oder räumlicher Rand jeder Dimension sind die ersten vom Vorgänger bewirkten Ereignisse, selbst raumzeitlicher Ursprung des Nachfolgers, dort einmalig und ewig maximal rotverschoben fortwirkend und nicht lokalisierbar, um neue Elementareinheiten verschieden und lichtartig mit deren Verhältnis oder dem ihrer globalen Zustandsgrößen als konstanten Anfangsimpuls, Expansion, Längen- oder Ereignisdichte zueinander. Der Übergang vom diskreten Modell weniger Informationen zum Kontinuum und die Korrespondenz zur Physik ist problemlos, Details wie ein kontinuierlicher, abrupter oder ganz fehlender Abfall der Metrik beim ältesten Gebiet sind aber nur durch Beobachtungen entscheidbar. Erörtert werden allgemeine und individuelle Eigenschaften und ihre Konsequenzen der Dimensionen mit ihren Kräften, selbst und im Verhältnis zueinander, etwa ihrer begrenzten

  17. Prenatal recruitment of participants for a birth cohort study including cord blood collection: results of a feasibility study in Bremen, Germany.

    PubMed

    Ernst, Sinja Alexandra; Günther, Kathrin; Frambach, Torsten; Zeeb, Hajo

    2015-01-01

    Hintergrund: Geburtskohorten stellen vielversprechende Forschungsansätze dar, um prospektiv unter Life-Course-Perspektive Ursachen und Mechanismen zahlreicher Erkrankungen zu erforschen. Die Entnahme von Bioproben, einschließlich Nabelschnurblutproben, zu verschiedenen Zeitpunkten im Lebensverlauf (insbesondere prä- und perinatal) ist von zentraler Bedeutung für eine direkte Expositionserfassung. Gleichzeitig ist die Entnahme von Bioproben als besonders kritischer Aspekt in epidemiologischen Studien zu betrachten, insbesondere für die Erforschung von pränatalen Expositionen durch umweltbezogene Faktoren und für DNA-Extraktion. Ziele dieser Machbarkeitsstudie zur Ursachenforschung für kindliche Leukämien war die Erstrekrutierung von werdenden Müttern sowie ihren zukünftigen Neugeborenen für eine Geburtskohorte, welche die Entnahme von Blut der Mutter sowie Nabelschnurblut beinhaltet. Übergreifendes Ziel war die Entwicklung von Empfehlungen für eine mögliche nationale Geburtskohorte auf Basis praktischer Erfahrungen.Methoden: Die Machbarkeitsstudie wurde in Bremen im Zeitraum Januar 2012 bis März 2013 durchgeführt. Werdende Mütter wurden um Studienteilnahme gebeten, wenn (i) der geplante Geburtstermin im Erhebungszeitraum lag, (ii) die Entbindung in der kooperierenden Geburtsklinik stattfinden sollte sowie (iii) die Sprachkenntnisse ausreichend waren, um die Studieninhalte zu verstehen und den pränatalen Fragebogen auszufüllen. Blut der Mutter sowie Nabelschnurblut wurde für spätere Forschungsaktivitäten gesammelt und in einer Stammzellbank eingelagert, die bereits eine bestehende Kooperation mit der Geburtsklinik hatte. 22 niedergelassene Gynäkologinnen und Gynäkologen wurden kontaktiert und gebeten werdende Mütter in die Studie einzuschließen. Die Rekrutierung erfolgte im letzten Schwangerschaftsdrittel, entweder im Rahmen der Schwangerenvorsorge bei niedergelassenen Gynäkologinnen oder Gynäkologen oder in der Geburtsklinik

  18. G-protein coupled receptor auto-antibodies in thromboangiitis obliterans (Buerger's disease) and their removal by immunoadsorption.

    PubMed

    Klein-Weigel, Peter F; Bimmler, Marion; Hempel, Petra; Schöpp, Sebastian; Dreusicke, Siegrid; Valerius, Jana; Bohlen, Anne; Boehnlein, Joana M; Bestler, Daniel; Funk, Stephanie; Elitok, Saban

    2014-09-01

    Hintergrund: Histopathologische und serologische Befunde sprechen für eine Immunpathogenese der Thromboangiitis obliterans (TAO, Buerger’sche Erkrankung). Autoantikörper scheinen eine wichtige Rolle im Krankheitsgeschehen zu spielen. Es wurden wiederholt positive therapeutische Effekte durch eine Immunadsorption (IA) gezeigt. Wir analysierten agonistische Autoantikörper (agAAK), die gegen G-Protein gekoppelte Rezeptoren (GPCR) gerichtet sind und analysierten, ob diese durch eine IA effektiv beseitigt werden können. Patienten und Methoden: Zwischen Dezember 2012 und Mai 2014 wurden 11 Patienten mittels IA über 5 konsekutive Tage behandelt. Die agAAK wurden unter Verwendung spezifischer ELISA-Techniken bestimmt. Ergebnisse: AgAAK wurden bei 9 von 11 Patienten (81.8 %) gefunden. Multiple agAAK waren bei 7 Patienten (63.6 %) nachweisbar. Darüber hinaus wurde ein agAAK-Cluster entdeckt, das sich gegen Loop1 des adrenergen α1-Rezeptors und Loop1 des Endothelin A (ETA)-Rezeptors richtet, und sich bei 72.7 % respektive 54.5 % der TAO-Patienten nachweisen ließ. AgAAK gegen Epitop 1 oder 2 des Angiotensin-1-Rezeptors wurden bei 3 Patienten, agAAK gegen Loop1/2 des Proteinase-aktivierten Rezeptor (PAR) wurden bei 2 Patienten nachgewiesen. AgAAK gegen den ETA-Rezeptor traten niemals ohne gleichzeitigen Nachweis von agAAK gegen den α1-adrenergen Rezeptor auf und waren immer gegen Loop1 gerichtet. Unmittelbar nach Beendigung der IA ließen sich bei 81.8 % aller Patienten und bei 77.8 % aller Fälle mit positiven agAAK vor der IA keine agAAK mehr nachgewiesen. Schlussfolgerungen: Wir konnten bei Patienten mit aktiver TAO agAAK gegen GPCR und darüber hinaus ein Antikörper-Cluster nachweisen, das sich bevorzugt gegen Loop1 des α-1-adrenergen Rezeptors und Loop1 des ETA-Rezeptors richtet. Die agAAK wurden mehrheitlich erfolgreich durch die IA eliminiert. Wir sind der Auffassung, dass gegen GPCR-gerichtete agAAK eine wichtige Rolle in der Pathogenese der TAO spielen und

  19. Power estimation on functional level for programmable processors

    NASA Astrophysics Data System (ADS)

    Schneider, M.; Blume, H.; Noll, T. G.

    2004-05-01

    In diesem Beitrag werden verschiedene Ansätze zur Verlustleistungsschätzung von programmierbaren Prozessoren vorgestellt und bezüglich ihrer Übertragbarkeit auf moderne Prozessor-Architekturen wie beispielsweise Very Long Instruction Word (VLIW)-Architekturen bewertet. Besonderes Augenmerk liegt hierbei auf dem Konzept der sogenannten Functional-Level Power Analysis (FLPA). Dieser Ansatz basiert auf der Einteilung der Prozessor-Architektur in funktionale Blöcke wie beispielsweise Processing-Unit, Clock-Netzwerk, interner Speicher und andere. Die Verlustleistungsaufnahme dieser Bl¨ocke wird parameterabhängig durch arithmetische Modellfunktionen beschrieben. Durch automatisierte Analyse von Assemblercodes des zu schätzenden Systems mittels eines Parsers können die Eingangsparameter wie beispielsweise der erzielte Parallelitätsgrad oder die Art des Speicherzugriffs gewonnen werden. Dieser Ansatz wird am Beispiel zweier moderner digitaler Signalprozessoren durch eine Vielzahl von Basis-Algorithmen der digitalen Signalverarbeitung evaluiert. Die ermittelten Schätzwerte für die einzelnen Algorithmen werden dabei mit physikalisch gemessenen Werten verglichen. Es ergibt sich ein sehr kleiner maximaler Schätzfehler von 3%. In this contribution different approaches for power estimation for programmable processors are presented and evaluated concerning their capability to be applied to modern digital signal processor architectures like e.g. Very Long InstructionWord (VLIW) -architectures. Special emphasis will be laid on the concept of so-called Functional-Level Power Analysis (FLPA). This approach is based on the separation of the processor architecture into functional blocks like e.g. processing unit, clock network, internal memory and others. The power consumption of these blocks is described by parameter dependent arithmetic model functions. By application of a parser based automized analysis of assembler codes of the systems to be estimated the input

  20. Characterizations of purple non-sulfur bacteria isolated from paddy fields, and identification of strains with potential for plant growth-promotion, greenhouse gas mitigation and heavy metal bioremediation.

    PubMed

    Sakpirom, Jakkapan; Kantachote, Duangporn; Nunkaew, Tomorn; Khan, Eakalak

    2017-04-01

    This study was aimed at selecting purple non-sulfur bacteria (PNSB) isolated from various paddy fields, including Cd- and Zn-contaminated paddy fields, based on their biofertilizer properties. Among 235 PNSB isolates, strain TN110 was most effective in plant growth-promoting substance (PGPS) production, releasing 3.2 mg/L of [Formula: see text] , 4.11 mg/L of 5-aminolevulinic acid (ALA) and 3.62 mg/L of indole-3-acetic acid (IAA), and reducing methane emission up to 80%. This strain had nifH, vnfG and anfG, which are the Mo, V and Fe nitrogenase genes encoded for key enzymes in nitrogen fixation under different conditions. This strain provided 84% and 55% removal of Cd and Zn, respectively. Another isolate, TN414, not only produced PGPS (1.30 mg/L of [Formula: see text] , 0.94 mg/L of ALA and 0.65 mg/L of IAA), but was also efficient in removing both Cd and Zn at 72% and 74%, respectively. Based on 16S rDNA sequencing, strain TN110 was identified as Rhodopseudomonas palustris, while strain TN414 was Rubrivivax gelatinosus. A combination of TN110 and TN414 could potentially provide a biofertilizer, which is a greener alternative to commercial/chemical fertilizers and an agent for bioremediation of heavy metals and greenhouse gas mitigation in paddy fields. Copyright © 2016 Institut Pasteur. All rights reserved.