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Sample records for comamonas denitrificans based

  1. Elevated level of the second messenger c-di-GMP in Comamonas testosteroni enhances biofilm formation and biofilm-based biodegradation of 3-chloroaniline.

    PubMed

    Wu, Yichao; Ding, Yuanzhao; Cohen, Yehuda; Cao, Bin

    2015-02-01

    The bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) is a ubiquitous second messenger that determines bacterial lifestyle between the planktonic and biofilm modes of life. Although the role of c-di-GMP signaling in biofilm development and dispersal has been extensively studied, how c-di-GMP signaling influences environmental bioprocess activities such as biodegradation remains unexplored. To elucidate the impacts of elevating c-di-GMP level on environmental bioprocesses, we constructed a Comamonas testosteroni strain constitutively expressing a c-di-GMP synthase YedQ from Escherichia coli and examined its capability in biofilm formation and biodegradation of 3-chloroaniline (3-CA). The high c-di-GMP strain exhibited an increased binding to Congo red dye, a decreased motility, and an enhanced biofilm formation capability. In planktonic cultures, the strain with an elevated c-di-GMP concentration and the wild type could degrade 3-CA comparably well. However, under batch growth conditions with a high surface to volume ratio, an elevated c-di-GMP concentration in C. testosteroni significantly increased the contribution of biofilms in 3-CA biodegradation. In continuous submerged biofilm reactors, C. testosteroni with an elevated c-di-GMP level exhibited an enhanced 3-CA biodegradation and a decreased cell detachment rate. Taken together, this study provides a novel strategy to enhance biofilm-based biodegradation of toxic xenobiotic compounds through manipulating bacterial c-di-GMP signaling.

  2. The 5S ribosomal RNAs of Paracoccus denitrificans and Prochloron

    NASA Technical Reports Server (NTRS)

    Mackay, R. M.; Salgado, D.; Bonen, L.; Doolittle, W. F.; Stackebrandt, E.

    1982-01-01

    The nucleotide sequences of the 5S rRNAs of Paracoccus denitrificans and Prochloron sp. are presented, along with the demonstrated phylogenetic relationships of P. denitrificans with purple nonsulfur bacteria, and of Prochloron with cyanobacteria. Structural findings include the following: (1) helix II in both models is much shorter than in other eubacteria, (2) a base-pair has been deleted from helix IV of P. denitrificans 5S, and (3) Prochloron 5S has the potential to form four base-pairs between residues. Also covered are the differences between pairs of sequences in P. denitrificans, Prochloron, wheat mitochondion, spinach chloroplast, and nine diverse eubacteria. Findings include the observation that Prochloron 5S rRNA is much more similar to the 5S of the cyanobacterium Anacystis nidulans (25 percent difference) than either are to any of the other nine eubacterial 5S rRNAs.

  3. The conserved cis-Pro39 residue plays a crucial role in the proper positioning of the catalytic base Asp38 in ketosteroid isomerase from Comamonas testosteroni.

    PubMed Central

    Nam, Gyu Hyun; Cha, Sun-Shin; Yun, Young Sung; Oh, Yun Hee; Hong, Bee Hak; Lee, Heung-Soo; Choi, Kwan Yong

    2003-01-01

    KSI (ketosteroid isomerase) from Comamonas testosteroni is a homodimeric enzyme that catalyses the allylic isomerization of Delta5-3-ketosteroids to their conjugated Delta4-isomers at a reaction rate equivalent to the diffusion-controlled limit. Based on the structural analysis of KSI at a high resolution, the conserved cis-Pro39 residue was proposed to be involved in the proper positioning of Asp38, a critical catalytic residue, since the residue was found not only to be structurally associated with Asp38, but also to confer a structural rigidity on the local active-site geometry consisting of Asp38, Pro39, Val40, Gly41 and Ser42 at the flexible loop between b-strands B1 and B2. In order to investigate the structural role of the conserved cis-Pro39 residue near the active site of KSI, Pro39 was replaced with alanine or glycine. The free energy of activation for the P39A and P39G mutants increased by 10.5 and 16.7 kJ/mol (2.5 and 4.0 kcal/mol) respectively, while DG(U)H2O (the free-energy change for unfolding in the absence of urea at 25.00+/-0.02 degrees C) decreased by 31.0 and 35.6 kJ/mol (7.4 and 8.5 kcal/mol) respectively, compared with the wild-type enzyme. The crystal structure of the P39A mutant in complex with d-equilenin [d-1,3,5(10),6,8-estrapentaen-3-ol-17-one], a reaction intermediate analogue, determined at 2.3 A (0.23 nm) resolution revealed that the P39A mutation significantly disrupted the proper orientations of both d-equilenin and Asp38, as well as the local active-site geometry near Asp38, which resulted in substantial decreases in the activity and stability of KSI. Upon binding 1-anilinonaphthalene-8-sulphonic acid, the fluorescence intensities of the P39A and P39G mutants were increased drastically, with maximum wavelengths blue-shifted upon binding, indicating that the mutations might alter the hydrophobic active site of KSI. Taken together, our results demonstrate that the conserved cis-Pro39 residue plays a crucial role in the proper

  4. Bacteremia Caused by Comamonas kerstersii in a Patient with Diverticulosis

    PubMed Central

    Opota, Onya; Ney, Barbara; Zanetti, Giorgio; Jaton, Katia; Prod'hom, Guy

    2014-01-01

    We report for the first time a case of bacteremia caused by Comamonas kerstersii in a 65-year-old patient with sign of diverticulosis. In addition, we review the isolation of Comamonas sp. and related organisms in our hospital over 25 years. PMID:24371242

  5. Genetic manipulation of the obligate chemolithoautotrophic bacterium Thiobacillus denitrificans

    SciTech Connect

    Beller, H.R.; Legler, T.C.; Kane, S.R.

    2011-07-15

    Chemolithoautotrophic bacteria can be of industrial and environmental importance, but they present a challenge for systems biology studies, as their central metabolism deviates from that of model organisms and there is a much less extensive experimental basis for their gene annotation than for typical organoheterotrophs. For microbes with sequenced genomes but unconventional metabolism, the ability to create knockout mutations can be a powerful tool for functional genomics and thereby render an organism more amenable to systems biology approaches. In this chapter, we describe a genetic system for Thiobacillus denitrificans, with which insertion mutations can be introduced by homologous recombination and complemented in trans. Insertion mutations are generated by in vitro transposition, the mutated genes are amplified by the PCR, and the amplicons are introduced into T. denitrificans by electroporation. Use of a complementation vector, pTL2, based on the IncP plasmid pRR10 is also addressed.

  6. Draft Genome Sequence of the Bacterium Comamonas aquatica CJG

    PubMed Central

    Zhu, Yutong; Wang, Xiqian; Sakenova, Nazgul; Yang, Zhenyu; Wang, Hongjuan; Li, Guoqiao; He, Jiajing; Huang, Deyu; Cai, Yongfei; Guo, Weizheng; Wang, Qian; Feng, Tingting; Fan, Quanshui; Zheng, Tianling

    2016-01-01

    A Gram-negative bacterial strain, Comamonas aquatica CJG, absorbs low-density lipoprotein but not high-density lipoprotein in serum. Here, we report its draft genomic sequence of 3,764,434 bp, containing total 3,425 genes, 27% of which encode proteins for metabolism and energy conversion, and it is 30% identical to the genome of Comamonas testosteroni. PMID:27811093

  7. Emended description of Kingella denitrificans (Snell and Lapage 1976): correction of the maltose reaction.

    PubMed

    Hollis, D G; Weaver, R E; Riley, P S

    1983-11-01

    Snell and Lapage proposed that the bacterium designated CDC group TM-1 be named Kingella denitrificans. Their description of the organism indicated that it produced acid from maltose which was in contrast with an earlier report from our laboratory that maltose was not utilized. In an attempt to explain the different findings in the two laboratories, the type strain and two additional strains of K. denitrificans were tested for acid production from maltose in phenol red broth, the rapid fermentation test, fermentation broth with Andrade's indicator, and oxidation-fermentation base. These media were tested without additional supplements and with supplements of horse serum (5% [vol/vol]) or rabbit serum (5% [vol/vol]). The results indicated that K. denitrificans does not produce acid from maltose. It was demonstrated that maltose in media containing serum is converted to glucose from which acid can be produced by K. denitrificans. The supplementation of maltose medium with horse serum by Snell and Lapage apparently had produced a false-positive maltose reaction. The description of K. denitrificans is emended to indicate that maltose is not utilized.

  8. Transfer of Halobacterium denitrificans (Tomlinson, Jahnke, and Hochstein) to the genus Haloferax as Haloferax denitrificans comb. nov

    NASA Technical Reports Server (NTRS)

    Tindall, B. J.; Tomlinson, G. A.; Hochstein, L. I.

    1989-01-01

    Halobacterium denitrificans (Tomlinson, Jahnke, and Hochstein) was described at a time when the taxonomic subdivision of the family Halobacteriaceae was in a state of flux. On the basis of both biochemical and chemotaxonomic data, this organism exhibits features which indicate that it is more closely related to members of the genus Haloferax. On the basis of such criteria, we propose that Halobacterium denitrificans be reclassified as Haloferax denitrificans comb. nov. The type strain is strain ATCC 35960 (= DSM 4425).

  9. Anoxic Androgen Degradation by the Denitrifying Bacterium Sterolibacterium denitrificans via the 2,3-seco Pathway

    PubMed Central

    Wang, Po-Hsiang; Yu, Chang-Ping; Lee, Tzong-Huei; Lin, Ching-Wen; Ismail, Wael; Wey, Shiaw-Pyng; Kuo, An-Ti

    2014-01-01

    The biodegradation of steroids is a crucial biochemical process mediated exclusively by bacteria. So far, information concerning the anoxic catabolic pathways of androgens is largely unknown, which has prevented many environmental investigations. In this work, we show that Sterolibacterium denitrificans DSMZ 13999 can anaerobically mineralize testosterone and some C19 androgens. By using a 13C-metabolomics approach and monitoring the sequential appearance of the intermediates, we demonstrated that S. denitrificans uses the 2,3-seco pathway to degrade testosterone under anoxic conditions. Furthermore, based on the identification of a C17 intermediate, we propose that the A-ring cleavage may be followed by the removal of a C2 side chain at C-5 of 17-hydroxy-1-oxo-2,3-seco-androstan-3-oic acid (the A-ring cleavage product) via retro-aldol reaction. The androgenic activities of the bacterial culture and the identified intermediates were assessed using the lacZ-based yeast androgen assay. The androgenic activity in the testosterone-grown S. denitrificans culture decreased significantly over time, indicating its ability to eliminate androgens. The A-ring cleavage intermediate (≤500 μM) did not exhibit androgenic activity, whereas the sterane-containing intermediates did. So far, only two androgen-degrading anaerobes (Sterolibacterium denitrificans DSMZ 13999 [a betaproteobacterium] and Steroidobacter denitrificans DSMZ 18526 [a gammaproteobacterium]) have been isolated and characterized, and both of them use the 2,3-seco pathway to anaerobically degrade androgens. The key intermediate 2,3-seco-androstan-3-oic acid can be used as a signature intermediate for culture-independent environmental investigations of anaerobic degradation of C19 androgens. PMID:24657867

  10. Genome of the epsilonproteobacterial chemolithoautotroph Sulfurimonas denitrificans

    SciTech Connect

    Sievert, Stefan M; Scott, Kathleen M; Klotz, Martin G; Chain, Patrick S. G.; Hauser, Loren John; Hemp, James; Hugler, Michael; Land, Miriam L; Lapidus, Alla L.; Larimer, Frank W; Lucas, Susan; Malfatti, Stephanie; Meyer, Folker; Paulsen, Ian T; Ren, Qinghu; Simon, Jorg

    2008-01-01

    Sulfur-oxidizing epsilonproteobacteria are common in a variety of sulfidogenic environments. These autotrophic and mixotrophic sulfur-oxidizing bacteria are believed to contribute substantially to the oxidative portion of the global sulfur cycle. In order to better understand the ecology and roles of sulfur-oxidizing epsilonproteobacteria, in particular those of the widespread genus Sulfurimonas, in biogeochemical cycles, the genome of Sulfurimonas denitrificans DSM1251 was sequenced. This genome has many features, including a larger size (2.2 Mbp), that suggest a greater degree of metabolic versatility or responsiveness to the environment than seen for most of the other sequenced epsilonproteobacteria. A branched electron transport chain is apparent, with genes encoding complexes for the oxidation of hydrogen, reduced sulfur compounds, and formate and the reduction of nitrate and oxygen. Genes are present for a complete, autotrophic reductive citric acid cycle. Many genes are present that could facilitate growth in the spatially and temporally heterogeneous sediment habitat from where Sulfurimonas denitrificans was originally isolated. Many resistance-nodulation-development family transporter genes (10 total) are present; of these, several are predicted to encode heavy metal efflux transporters. An elaborate arsenal of sensory and regulatory protein-encoding genes is in place, as are genes necessary to prevent and respond to oxidative stress.

  11. Comamonas testosteroni: Is It Still a Rare Human Pathogen?

    PubMed Central

    Farooq, Shaika; Farooq, Rumana; Nahvi, Nahida

    2017-01-01

    Comamonas testosteroni (formally Pseudomonas testosteroni) is common environmental bacterium that is not part of the human microbiome. Since its identification as a human pathogen in 1987, numerous reports have drizzled in, implicating this organism for various infections. Although these organisms are of low virulence, some of their obscurity perhaps is due to the incapability of clinical laboratories to identify them. Most of the reported cases are bloodstream infections. We report a case of gastroenteritis caused by this organism in a 65-year-old female with colostomy in situ. PMID:28203137

  12. Permanent draft genome sequence of Comamonas testosteroni KF-1

    SciTech Connect

    Weiss, Michael; Kesberg, Anna I; LaButti, Kurt; Pitluck, Sam; Bruce, David; Hauser, Loren John; Copeland, A; Woyke, Tanja; Lowry, Stephen; Lucas, Susan; Land, Miriam L; Goodwin, Lynne A.; Kjelleberg, Staffan; Cook, Alasdair M.; Buhmann, Matthias; Thomas, Torsten; Schleheck, David

    2013-01-01

    Comamonas testosteroni KF-1 is a model organism for the elucidation of the novel biochemical degra- dation pathways for xenobiotic 4-sulfophenylcarboxylates (SPC) formed during biodegradation of syn- thetic 4-sulfophenylalkane surfactants (linear alkylbenzenesulfonates, LAS) by bacterial communities. Here we describe the features of this organism, together with the complete genome sequence and an- notation. The 6,026,527 bp long chromosome (one sequencing gap) exhibits an average G+C content of 61.79% and is predicted to encode 5,492 protein-coding genes and 114 RNA genes.

  13. [Comparative susceptibility of Ochrobactrum anthropi, Agrobacterium tumefaciens, Alcaligenes faecalis, Alcaligenes denitrificans subsp. denitrificans, Alcaligenes denitrificans subsp. xylosidans and Bordetella bronchiseptica against 35 antibiotics including 17 beta-lactams].

    PubMed

    Bizet, C; Bizet, J

    1995-04-01

    Ochrobactrum anthropi, formerly known as "Achromobacter sp." or CDC group Vd has been isolated from water, hospital environment (antiseptic solutions, dialysis fluids ... ). O. anthropi is a Gram negative, motile, strictly aerobic, oxydase positive and non-fermentative bacteria with a strong urease activity. The susceptibility of 13 strains of O. anthropi was determined by agar diffusion method and compared to those of type strains of Agrobacterium tumefaciens, Alcaligenes faecalis, Alcaligenes denitrificans subsp. denitrificans, Alcaligenes denitrificans subsp. xylosoxydans and Bordetella bronchiseptica. The MICs of 20 antimicrobial agents confirmed the distinct phenotype susceptibility of O. anthropi. All the strains of O. anthropi are sensitive to imipenem, amikacin, gentamicin, netilmicin, nalidixic acid, pefloxacin, ciprofloxacin, tetracyclin, colistin, sulphonamides and rifampicin and resistant to ampicillin, amoxycillin + clavulanic acid, ticarcillin, mezlocillin, cefuroxime, cefamandol, cefoxitin, cefotaxime, cefoperazon, ceftazidime, cefsulodin, aztreonam, streptomycin, kanamycin, pipemidic acid, chloramphenicol, erythromicin, pristinamycin, trimethoprim and fosfomycin. O. anthropi is implicated in nosocomial infections. O. anthropi was the species with the greatest resistance to beta-lactamins.

  14. Identification of a Thiomicrospira denitrificans-Like Epsilonproteobacterium as a Catalyst for Autotrophic Denitrification in the Central Baltic Sea†

    PubMed Central

    Brettar, Ingrid; Labrenz, Matthias; Flavier, Sébastien; Bötel, Julia; Kuosa, Harri; Christen, Richard; Höfle, Manfred G.

    2006-01-01

    Identification and functional analysis of key members of bacterial communities in marine and estuarine environments are major challenges for obtaining a mechanistic understanding of biogeochemical processes. In the Baltic Sea basins, as in many other marine environments with anoxic bodies of water, the oxic-anoxic interface is considered a layer of high bacterial turnover of sulfur, nitrogen, and carbon compounds that has a great impact on matter balances in the whole ecosystem. We focused on autotrophic denitrification by oxidation of reduced sulfur compounds as a biogeochemically important process mediating concomitant turnover of sulfur, nitrogen, and carbon. We used a newly developed approach consisting of molecular analyses in stimulation experiments and in situ abundance. The molecular approach was based on single-strand conformational polymorphism (SSCP) analysis of the bacterial community RNA, which allowed identification of potential denitrifiers based on the sequences of enhanced SSCP bands and monitoring of the overall bacterial community during the experiments. Sequences of the SSCP bands of interest were used to design highly specific primers that enabled (i) generation of almost complete 16S rRNA gene sequences using experimental and environmental DNA as templates and (ii) quantification of the bacteria of interest by real-time PCR. By using this approach we identified the bacteria responsible for autotrophic denitrification as a single taxon, an epsilonproteobacterium related to the autotrophic denitrifier Thiomicrospira denitrificans. This finding was confirmed by material balances in the experiments that were consistent with those obtained with continuous cultures of T. denitrificans. The presence and activity of a bacterium that is phylogenetically and physiologically closely related to T. denitrificans could be relevant for the carbon budget of the central Baltic Sea because T. denitrificans exhibits only one-half the efficiency for carbon

  15. The terminal oxidases of Paracoccus denitrificans.

    PubMed

    de Gier, J W; Lübben, M; Reijnders, W N; Tipker, C A; Slotboom, D J; van Spanning, R J; Stouthamer, A H; van der Oost, J

    1994-07-01

    Three distinct types of terminal oxidases participate in the aerobic respiratory pathways of Paracoccus denitrificans. Two alternative genes encoding subunit I of the aa3-type cytochrome c oxidase have been isolated before, namely ctaDI and ctaDII. Each of these genes can be expressed separately to complement a double mutant (delta ctaDI, delta ctaDII), indicating that they are isoforms of subunit I of the aa3-type oxidase. The genomic locus of a quinol oxidase has been isolated: cyoABC. This protohaem-containing oxidase, called cytochrome bb3, is the only quinol oxidase expressed under the conditions used. In a triple oxidase mutant (delta ctaDI, delta ctaDII, cyoB::KmR) an alternative cytochrome c oxidase has been characterized; this cbb3-type oxidase has been partially purified. Both cytochrome aa3 and cytochrome bb3 are redox-driven proton pumps. The proton-pumping capacity of cytochrome cbb3 has been analysed; arguments for and against the active transport of protons by this novel oxidase complex are discussed.

  16. Halobacterium denitrificans sp. nov. - An extremely halophilic denitrifying bacterium

    NASA Technical Reports Server (NTRS)

    Tomlinson, G. A.; Jahnke, L. L.; Hochstein, L. I.

    1986-01-01

    Halobacterium denitrificans was one of several carbohydrate-utilizing, denitrifying, extremely halophilic bacteria isolated by anaerobic enrichment in the presence of nitrate. Anaerobic growth took place only when nitrate (or nitrite) was present and was accompanied by the production of dinitrogen. In the presence of high concentrations of nitrate (i.e., 0.5 percent), nitrous oxide and nitrite were also detected. When grown aerobically in a mineral-salts medium containing 0.005 percent yeast extract, H. denitrificans utilized a variety of carbohydrates as sources of carbon and energy. In every case, carbohydrate utilization was accompanied by acid production.

  17. Halobacterium denitrificans sp. nov., an extremely halophilic denitrifying bacterium

    NASA Technical Reports Server (NTRS)

    Tomlinson, G. A.; Jahnke, L. L.; Hochstein, L. I.

    1986-01-01

    Halobacterium denitrificans was one of several carbohydrate-utilizing, denitrifying, extremely halophilic bacteria isolated by anaerobic enrichment in the presence of nitrate. Anaerobic growth took place only when nitrate (or nitrite) was present and was accompanied by the production of dinitrogen. In the presence of high concentrations of nitrate (i.e., 0.5 percent), nitrous oxide and nitrite were also detected. When grown aerobically in a mineral-salts medium containing 0.005 percent yeast extract, H. denitrificans utilized a variety of carbohydrates as sources of carbon and energy. In every case, carbohydrate utilization was accompanied by acid production.

  18. Identification of Comamonas testosteroni as an androgen degrader in sewage

    PubMed Central

    Chen, Yi-Lung; Wang, Chia-Hsiang; Yang, Fu-Chun; Ismail, Wael; Wang, Po-Hsiang; Shih, Chao-Jen; Wu, Yu-Ching; Chiang, Yin-Ru

    2016-01-01

    Numerous studies have reported the masculinization of freshwater wildlife exposed to androgens in polluted rivers. Microbial degradation is a crucial mechanism for eliminating steroid hormones from contaminated ecosystems. The aerobic degradation of testosterone was observed in various bacterial isolates. However, the ecophysiological relevance of androgen-degrading microorganisms in the environment is unclear. Here, we investigated the biochemical mechanisms and corresponding microorganisms of androgen degradation in aerobic sewage. Sewage samples collected from the Dihua Sewage Treatment Plant (Taipei, Taiwan) were aerobically incubated with testosterone (1 mM). Androgen metabolite analysis revealed that bacteria adopt the 9, 10-seco pathway to degrade testosterone. A metagenomic analysis indicated the apparent enrichment of Comamonas spp. (mainly C. testosteroni) and Pseudomonas spp. in sewage incubated with testosterone. We used the degenerate primers derived from the meta-cleavage dioxygenase gene (tesB) of various proteobacteria to track this essential catabolic gene in the sewage. The amplified sequences showed the highest similarity (87–96%) to tesB of C. testosteroni. Using quantitative PCR, we detected a remarkable increase of the 16S rRNA and catabolic genes of C. testosteroni in the testosterone-treated sewage. Together, our data suggest that C. testosteroni, the model microorganism for aerobic testosterone degradation, plays a role in androgen biodegradation in aerobic sewage. PMID:27734937

  19. Solubilized cytochrome c oxidase from Paracoccus denitrificans is a monomer.

    PubMed

    Ludwig, B; Grabo, M; Gregor, I; Lustig, A; Regenass, M; Rosenbusch, J P

    1982-05-25

    Cytochrome c oxidase purified from the bacterium Paracoccus denitrificans was analyzed by analytical ultracentrifugation. In the detergent octyltetra/pentaoxyethylene (C8E45), the isolated enzyme exhibits a molecular weight of 79,000 to 84,000. The detergent-solubilized enzyme is thus a monomer which contains one copy of each of the two subunits.

  20. Environmentally safe treatment of black liquor with Comamonas sp. B-9 under high-alkaline conditions.

    PubMed

    Zheng, Yu; Chai, Liyuan; Yang, Zhihui; Chen, Yuehui; Shi, Yan; Wang, Yangyang

    2014-02-01

    The strain Comamonas sp. B-9 was isolated from steeping fluid of erosive bamboo slips derived from Kingdom Wu during the Three-Kingdoms Dynasty of ancient China (A.D. 220-280). It could be used to treat black liquor (BL) with high-alkaline pH and with an initial chemical oxygen demand (COD) of 18,000-25,000 mg L(-1) , without the addition of other carbon and nitrogen sources. The results revealed that Comamonas sp. B-9 was capable of reducing the COD, color, and lignin content of BL by up to 56.8, 35.3, and 43.5%, respectively. High levels of laccase, manganese peroxidase, cellulase, and xylanase enzymatic activities were also observed, and these enzymes could play an important role in the biotreatment of BL. Further, GC-MS analysis showed that most of the compounds detected in BL after biotreatment with Comamonas sp. B-9 were diminished, while 4-methyl benzaldehyde, 3,4,5-trihydroxybenzoic acid ethyl ester, and 4-hydroxy-3,5-dimethoxy benzaldehyde were produced as metabolites. The presented results indicate that Comamonas sp. B-9 has potential application for the treatment of wastewaters from pulp and paper processing with high COD load under high-alkaline conditions.

  1. Paracoccus denitrificans possesses two BioR homologs having a role in regulation of biotin metabolism.

    PubMed

    Feng, Youjun; Kumar, Ritesh; Ravcheev, Dmitry A; Zhang, Huimin

    2015-08-01

    Recently, we determined that BioR, the GntR family of transcription factor, acts as a repressor for biotin metabolism exclusively distributed in certain species of α-proteobacteria, including the zoonotic agent Brucella melitensis and the plant pathogen Agrobacterium tumefaciens. However, the scenario is unusual in Paracoccus denitrificans, another closely related member of the same phylum α-proteobacteria featuring with denitrification. Not only does it encode two BioR homologs Pden_1431 and Pden_2922 (designated as BioR1 and BioR2, respectively), but also has six predictive BioR-recognizable sites (the two bioR homolog each has one site, whereas the two bio operons (bioBFDAGC and bioYB) each contains two tandem BioR boxes). It raised the possibility that unexpected complexity is present in BioR-mediated biotin regulation. Here we report that this is the case. The identity of the purified BioR proteins (BioR1 and BioR2) was confirmed with LC-QToF-MS. Phylogenetic analyses combined with GC percentage raised a possibility that the bioR2 gene might be acquired by horizontal gene transfer. Gel shift assays revealed that the predicted BioR-binding sites are functional for the two BioR homologs, in much similarity to the scenario seen with the BioR site of A. tumefaciens bioBFDAZ. Using the A. tumefaciens reporter system carrying a plasmid-borne LacZ fusion, we revealed that the two homologs of P. denitrificans BioR are functional repressors for biotin metabolism. As anticipated, not only does the addition of exogenous biotin stimulate efficiently the expression of bioYB operon encoding biotin transport/uptake system BioY, but also inhibits the transcription of the bioBFDAGC operon resembling the de novo biotin synthetic pathway. EMSA-based screening failed to demonstrate that the biotin-related metabolite is involved in BioR-DNA interplay, which is consistent with our former observation with Brucella BioR. Our finding defined a complex regulatory network for biotin

  2. Genome sequences of Alicycliphilus denitrificans strain BC and K601(T)

    SciTech Connect

    Oosterkamp, Margreet J.; Veuskens, Teun; Plugge, Caroline M.; Langenhoff, A. M.; Gerritse, Jan; Van Berkel, Willem J. H.; Pieper, Dietmar; Junca, Howard; Goodwin, Lynne A.; Daligault, Hajnalka E.; Bruce, David; Detter, J. Chris; Tapia, Roxanne; Han, Cliff; Land, Miriam L; Hauser, Loren John; Smidt, Hauke; Stams, Alfons J. M.

    2011-01-01

    Alicycliphilus denitrificans strain BC and A. denitrificans strain K601T degrade cyclic hydrocarbons. These strains have been isolated from a mixture of wastewater treatment plant material and benzene-polluted soil and from a wastewater treatment plant, respectively, suggesting their role in bioremediation of soil and water. Although the strains are phylogenetically closely related, there are some clear physiological differences. The hydrocarbon cyclohexanol, for example, can be degraded by strain K601T but not by strain BC. Furthermore, both strains can use nitrate and oxygen as an electron acceptor, but only strain BC can use chlorate as electron acceptor. To better understand the nitrate and chlorate reduction mechanisms coupled to the oxidation of cyclic compounds, the genomes of A. denitrificans strains BC and K601T were sequenced. Here, we report the complete genome sequences of A. denitrificans strains BC and K601T.

  3. Rapid purification of cytochrome c oxidase from Paracoccus denitrificans.

    PubMed

    Steffens, G C; Pascual, E; Buse, G

    1990-11-23

    Two methods are described for the purification of cytochrome c oxidase from Triton X-100 extracts of the periplasma membrane of Paracoccus denitrificans. The first is a large-scale procedure for the preparation of 100-250 nmol of cytochrome c oxidase (10-20 mg) in 1 week. The second is a rapid procedure for isolating up to 25 nmol in 2-3 days. Owing to the high yields given by fast protein liquid chromatography (FPLC) on Mono Q columns, the overall yield is about 20%, whereas the yield in many other previously published procedures does not exceed 10%. The use of FPLC on Mono Q also offers a considerable saving of time.

  4. Anaerobic Production of Thiobacillus denitrificans for the Enzyme Rhodanese

    PubMed Central

    Sargeant, K.; Buck, P. W.; Ford, J. W. S.; Yeo, R. G.

    1966-01-01

    A method for the anaerobic growth of Thiobacillus denitrificans in a 140-liter (total capacity) stainless-steel culture vessel is described. As a result of controlling the pH value of cultures, and of ensuring that certain essential nutrients were in excess, cell yields approaching 700 mg (dry weight) per liter were obtained. These were over threefold higher than the best yields hitherto reported. The average rhodanese content of the cells from four cultures was 176,000 units per gram (dry weight). Adenosine-5′-phosphosulfate reductase (average content, 238 units per gram dry weight) and adenylate kinase (average content, 15,300 units per gram, dry weight) were also present. PMID:16349709

  5. Substrate Uptake and Subcellular Compartmentation of Anoxic Cholesterol Catabolism in Sterolibacterium denitrificans*

    PubMed Central

    Lin, Ching-Wen; Wang, Po-Hsiang; Ismail, Wael; Tsai, Yu-Wen; El Nayal, Ashraf; Yang, Chia-Ying; Yang, Fu-Chun; Wang, Chia-Hsiang; Chiang, Yin-Ru

    2015-01-01

    Cholesterol catabolism by actinobacteria has been extensively studied. In contrast, the uptake and catabolism of cholesterol by Gram-negative species are poorly understood. Here, we investigated microbial cholesterol catabolism at the subcellular level. 13C metabolomic analysis revealed that anaerobically grown Sterolibacterium denitrificans, a β-proteobacterium, adopts an oxygenase-independent pathway to degrade cholesterol. S. denitrificans cells did not produce biosurfactants upon growth on cholesterol and exhibited high cell surface hydrophobicity. Moreover, S. denitrificans did not produce extracellular catabolic enzymes to transform cholesterol. Accordingly, S. denitrificans accessed cholesterol by direction adhesion. Cholesterol is imported through the outer membrane via a putative FadL-like transport system, which is induced by neutral sterols. The outer membrane steroid transporter is able to selectively import various C27 sterols into the periplasm. S. denitrificans spheroplasts exhibited a significantly higher efficiency in cholest-4-en-3-one-26-oic acid uptake than in cholesterol uptake. We separated S. denitrificans proteins into four fractions, namely the outer membrane, periplasm, inner membrane, and cytoplasm, and we observed the individual catabolic reactions within them. Our data indicated that, in the periplasm, various periplasmic and peripheral membrane enzymes transform cholesterol into cholest-4-en-3-one-26-oic acid. The C27 acidic steroid is then transported into the cytoplasm, in which side-chain degradation and the subsequent sterane cleavage occur. This study sheds light into microbial cholesterol metabolism under anoxic conditions. PMID:25418128

  6. Comamonas testosteroni uses a chemoreceptor for tricarboxylic acid cycle intermediates to trigger chemotactic responses towards aromatic compounds.

    PubMed

    Ni, Bin; Huang, Zhou; Fan, Zheng; Jiang, Cheng-Ying; Liu, Shuang-Jiang

    2013-11-01

    Bacterial chemotaxis towards aromatic compounds has been frequently observed; however, knowledge of how bacteria sense aromatic compounds is limited. Comamonas testosteroni CNB-1 is able to grow on a range of aromatic compounds. This study investigated the chemotactic responses of CNB-1 to 10 aromatic compounds. We constructed a chemoreceptor-free, non-chemotactic mutant, CNB-1Δ20, by disruption of all 19 putative methyl-accepting chemotaxis proteins (MCPs) and the atypical chemoreceptor in strain CNB-1. Individual complementation revealed that a putative MCP (tagged MCP2201) was involved in triggering chemotaxis towards all 10 aromatic compounds. The recombinant sensory domain of MCP2201 did not bind to 3- or 4-hydroxybenzoate, protocatechuate, catechol, benzoate, vanillate and gentisate, but bound oxaloacetate, citrate, cis-aconitate, isocitrate, α-ketoglutarate, succinate, fumarate and malate. The mutant CNB-1ΔpmdF that lost the ability to metabolize 4-hydroxybenzoate and protocatechuate also lost its chemotactic response to these compounds, suggesting that taxis towards aromatic compounds is metabolism-dependent. Based on the ligand profile, we proposed that MCP2201 triggers taxis towards aromatic compounds by sensing TCA cycle intermediates. Our hypothesis was further supported by the finding that introduction of the previously characterized pseudomonad chemoreceptor (McpS) for TCA cycle intermediates into CNB-1Δ20 likewise triggered chemotaxis towards aromatic compounds.

  7. Biodegradation of Direct Red 5B, a textile dye by newly isolated Comamonas sp. UVS.

    PubMed

    Jadhav, Umesh U; Dawkar, Vishal V; Ghodake, Gajanan S; Govindwar, Sanjay P

    2008-10-30

    Soil samples collected from the vicinity of "Manpasand textile industry", located near Ichalkaranji, India were studied for screening and isolation of bacterial strains capable of degradation of textile dyes. A potential strain was selected on the basis of rapid dye degradation and later identified as Comamonas sp. UVS. Comamonas sp. UVS showed 100% decolorization of Direct Red 5B (DR5B) dye at 40 degrees C and pH 6.5. The maximum Direct Red 5B concentration decolorized was 1,100 mg/l in nutrient broth within 125 h. A numerical simulation with the Michaelis-Menten kinetics model gives an optimal value of 16.01+/-0.36 mg dye/g cell/h for maximum rate (V(max)) and 7.97+/-0.21 mg/l for the Michaelis constant (K(m)). The induction in the activities of laccase and LiP was observed during decolorization. These enzymes were inhibited by the addition of sodium azide. The biodegradation was monitored by UV-vis, FTIR spectroscopy and HPLC. The GCMS analysis indicated the presence of 7-benzoylamino-3-diazenyl-4-hydroxy-naphthalene-2-sulfonic acid in degraded product of the dye. The germination of Triticum aestivum seeds was inhibited with DR5B treatment but not with the treatment of dye degradation products.

  8. Production of 3-hydroxypropionic acid from glycerol by recombinant Pseudomonas denitrificans.

    PubMed

    Zhou, Shengfang; Catherine, Christy; Rathnasingh, Chelladurai; Somasundar, Ashok; Park, Sunghoon

    2013-12-01

    3-Hydroxypropionic acid (3-HP) can be produced from glycerol through two sequential enzymatic reactions that are catalyzed by a coenzyme B12 -dependent glycerol dehydratase and an NAD(P)(+) -dependent aldehyde dehydrogenase (ALDH), respectively. Pseudomonas denitrificans synthesizes coenzyme B12 under aerobic conditions, where NAD(P)(+) is regenerated efficiently. Hence, it is considered an ideal host for the production of 3-HP from glycerol under aerobic conditions. In this study, recombinant strains of P. denitrificans were developed and their potential for the production of 3-HP from glycerol was evaluated. When the enzymes, glycerol dehydratase (DhaB) and glycerol dehydratase reactivase (GdrAB), of Klebsiella pneumoniae were expressed heterologously, P. denitrificans could produce 3-HP at 37.7 mmol/L with 62% (mol/mol) yield on glycerol. Glucose was required as the carbon and energy sources for cell growth. The overexpression of heterologous ALDH was not essential; however, the titer and yield of 3-HP were improved to 54.7 mmol/L and 67% (mol/mol), respectively, when an ALDH gene (puuC) from K. pneumoniae was overexpressed. One serious drawback hindering the use of P. denitrificans as a recombinant host for 3-HP production is that it oxidizes 3-HP to malonate and utilizes 3-HP as a carbon source for growth. This is the first report on the development and use of recombinant P. denitrificans for 3-HP production from glycerol.

  9. Draft Genome Sequence of Comamonas thiooxydans Strain PHE2-6 (NBRC 110656), a Chlorinated-Ethene-Degrading Bacterium

    PubMed Central

    Shimodaira, Jun; Yonezuka, Kenta; Tabata, Michiro; Nagase, Shun; Kasai, Daisuke; Hosoyama, Akira; Yamazoe, Atsushi; Fujita, Nobuyuki

    2016-01-01

    Comamonas thiooxydans strain PHE2-6 (NBRC 110656), which was isolated from a trichloroethene-contaminated site in Japan, utilizes phenol as a sole source of carbon and cometabolizes cis- and trans-dichloroethenes. We report here the draft genome sequence of this strain, containing 5,309,680 bp, with 60.6% G+C content. PMID:27340052

  10. Steroidobacter denitrificans gen. nov., sp. nov., a steroidal hormone-degrading gammaproteobacterium.

    PubMed

    Fahrbach, Michael; Kuever, Jan; Remesch, Markko; Huber, Birgit E; Kämpfer, Peter; Dott, Wolfgang; Hollender, Juliane

    2008-09-01

    A denitrifying bacterium, designated strain FS(T), was isolated from anoxic digested sludge on oestradiol [17beta-oestra-1,3,5(10)-triene-3,17-diol] or testosterone (17beta-hydroxyandrost-4-en-3-one) as the sole source of carbon and energy with nitrate as the electron acceptor. Strain FS(T) represents the first known bacterium to grow anaerobically on both oestradiol (C-18) and testosterone (C-19). Steroidal hormones were degraded completely by nitrate reduction to dinitrogen monoxide, which was further reduced to dinitrogen in stationary-phase cultures. Gram-negative cells were slightly curved rods, 0.3-0.5 x 0.6-1.6 microm in size, motile, non-fermentative, non-spore-forming and catalase- and oxidase-positive, showing optimal growth at pH 7.0, 28 degrees C and 0.1% (w/v) NaCl. Beside steroidal hormones, the bacterium utilized only a narrow range of organic substrates with nitrate as the electron acceptor, including several fatty acids and glutamate. No aerobic or anaerobic growth occurred on liquid or solid complex media. Phylogenetic analysis of the 16S rRNA gene sequence showed that strain FS(T) has no known close relatives and represents a distinct lineage within the Gammaproteobacteria. Together with the genera Nevskia, Hydrocarboniphaga, Solimonas and Sinobacter (less than 88% 16S rRNA gene sequence similarity to strain FS(T)), it forms a phylogenetic cluster separated from the families Chromatiaceae, Ectothiorhodospiraceae and Xanthomonadaceae. The quinone system of strain FS(T) consisted exclusively of ubiquinone Q-8. The dominant polar lipids were diphosphatidylglycerol and phosphatidylethanolamine. Spermidine in combination with putrescine and traces of sym-homospermidine were the basic polyamines. The major fatty acids detected in testosterone- or heptanoate-grown cells were C(15:0) and C(17:1)omega8c, minor hydroxylated fatty acids were C(11:0) 3-OH and C(12:0) 3-OH. The G+C content of the DNA was 61.9 mol%. Based on the high 16S rRNA gene sequence

  11. Kinetics of iron acquisition from ferric siderophores by Paracoccus denitrificans

    SciTech Connect

    Bergeron, R.J.; Weimar, W.R. )

    1990-05-01

    The kinetics of iron accumulation by iron-starved Paracoccus denitrificans during the first 2 min of exposure to 55Fe-labeled ferric siderophore chelates is described. Iron is acquired from the ferric chelate of the natural siderophore L-parabactin in a process exhibiting biphastic kinetics by Lineweaver-Burk analysis. The kinetic data for 1 microM less than (Fe L-parabactin) less than 10 microM fit a regression line which suggests a low-affinity system (Km = 3.9 +/- 1.2 microM, Vmax = 494 pg-atoms of 55Fe min-1 mg of protein-1), whereas the data for 0.1 microM less than or equal to (Fe L-parabactin) less than or equal to 1 microM fit another line consistent with a high-affinity system (Km = 0.24 +/- 0.06 microM, Vmax = 108 pg-atoms of 55Fe min-1 mg of protein-1). The Km of the high-affinity uptake is comparable to the binding affinity we had previously reported for the purified ferric L-parabactin receptor protein in the outer membrane. In marked contrast, ferric D-parabactin data fit a single regression line corresponding to a simple Michaelis-Menten process with comparatively low affinity (Km = 3.1 +/- 0.9 microM, Vmax = 125 pg-atoms of 55Fe min-1 mg of protein-1). Other catecholamide siderophores with an intact oxazoline ring derived from L-threonine (L-homoparabactin, L-agrobactin, and L-vibriobactin) also exhibit biphasic kinetics with a high-affinity component similar to ferric L-parabactin. Circular dichroism confirmed that these ferric chelates, like ferric L-parabactin, exist as the lambda enantiomers.

  12. The metabolic impact of extracellular nitrite on aerobic metabolism of Paracoccus denitrificans.

    PubMed

    Hartop, K R; Sullivan, M J; Giannopoulos, G; Gates, A J; Bond, P L; Yuan, Z; Clarke, T A; Rowley, G; Richardson, D J

    2017-02-07

    Nitrite, in equilibrium with free nitrous acid (FNA), can inhibit both aerobic and anaerobic growth of microbial communities through bactericidal activities that have considerable potential for control of microbial growth in a range of water systems. There has been much focus on the effect of nitrite/FNA on anaerobic metabolism and so, to enhance understanding of the metabolic impact of nitrite/FNA on aerobic metabolism, a study was undertaken with a model denitrifying bacterium Paracoccus denitrificans PD1222. Extracellular nitrite inhibits aerobic growth of P. denitrificans in a pH-dependent manner that is likely to be a result of both nitrite and free nitrous acid (pKa = 3.25) and subsequent reactive nitrogen oxides generated from the intracellular passage of FNA into P. denitrificans. Increased expression of a gene encoding a flavohemoglobin protein (Fhp) (Pden_1689) was observed in response to extracellular nitrite. Construction and analysis of a deletion mutant established Fhp to be involved in endowing nitrite/FNA resistance at high extracellular nitrite concentrations. Global transcriptional analysis confirmed nitrite-dependent expression of fhp and indicated that P. denitrificans expressed a number of stress response systems associated with protein, DNA and lipid repair. It is therefore suggested that nitrite causes a pH-dependent stress response that is due to the production of associated reactive nitrogen species, such as nitric oxide from the internalisation of FNA.

  13. Effect of electromagnetic fields on the denitrification activity of Paracoccus denitrificans.

    PubMed

    Fojt, Lukás; Strasák, Ludek; Vetterl, Vladimír

    2007-01-01

    Enzymatic activity (denitrification) of Paracoccus denitrificans was estimated electrochemically by reduction of duroquinone (DQ). Graphite electrodes covered with whole bacterial cells behind a dialysis membrane were used for measurement. P. denitrificans reduce nitrate and/or nitrite under anaerobic conditions to nitrogen gas. DQ acts as an electron mediator. After donation of the electrons to the respiratory system of the bacteria, produced DQ is reduced to durohydroquinone on the electrode surface electrocatalytically. P. denitrificans were exposed to low-frequency magnetic field (10 mT, 50 Hz) for 24 min. In comparison with the control samples, the reduction peak of I-E curves that represent denitrification activity of the cells decreased significantly after magnetic field exposure. The decrease of the peak current was about 20%. The CFU-colony forming units-method was used to estimate the number of surviving bacteria. After 24 min exposure of 10 mT magnetic field P. denitrificans culture on electrode indicates 21% bacterial death.

  14. Colonization of an acid resistant Kingella denitrificans in the stomach may contribute to gastric dysbiosis by Helicobacter pylori.

    PubMed

    Okamoto, Takeshi; Hayashi, Yasuhiro; Mizuno, Hidekazu; Yanai, Hideo; Nishikawa, Jun; Nakazawa, Teruko; Iizasa, Hisashi; Jinushi, Masahisa; Sakaida, Isao; Yoshiyama, Hironori

    2014-03-01

    In the stomach of a gastric ulcer patient who had been administered an anti-acid, a gram-negative and urease-negative bacillus similar in size to Helicobacter pylori was infected together with H. pylori. According to biochemical test and 16S rRNA gene analysis, the urease-negative bacterium was identified as Kingella denitrificans, a human nasopharyngeal commensal. In contrast to the standard strain of K. denitrificans, the isolate showed catalase activity, did not produce acid from glucose, and exhibited acid tolerance. Acid tolerance of H. pylori was increased by cocultivation with the K. denitrificans isolate, but not with other isolates of K. denitrificans. Disruption of physiological and immunological niche by dysbiotic colonization of bacterium may provide pathological attributes to human stomach. Collectively, a careful administration of anti-acids to the elderly, especially those with atrophic gastritis, is necessary to avoid repression of the gastric barrier to bacteria.

  15. The nitric-oxide reductase from Paracoccus denitrificans uses a single specific proton pathway.

    PubMed

    ter Beek, Josy; Krause, Nils; Reimann, Joachim; Lachmann, Peter; Ädelroth, Pia

    2013-10-18

    The NO reductase from Paracoccus denitrificans reduces NO to N2O (2NO + 2H(+) + 2e(-) → N2O + H2O) with electrons donated by periplasmic cytochrome c (cytochrome c-dependent NO reductase; cNOR). cNORs are members of the heme-copper oxidase superfamily of integral membrane proteins, comprising the O2-reducing, proton-pumping respiratory enzymes. In contrast, although NO reduction is as exergonic as O2 reduction, there are no protons pumped in cNOR, and in addition, protons needed for NO reduction are derived from the periplasmic solution (no contribution to the electrochemical gradient is made). cNOR thus only needs to transport protons from the periplasm into the active site without the requirement to control the timing of opening and closing (gating) of proton pathways as is needed in a proton pump. Based on the crystal structure of a closely related cNOR and molecular dynamics simulations, several proton transfer pathways were suggested, and in principle, these could all be functional. In this work, we show that residues in one of the suggested pathways (denoted pathway 1) are sensitive to site-directed mutation, whereas residues in the other proposed pathways (pathways 2 and 3) could be exchanged without severe effects on turnover activity with either NO or O2. We further show that electron transfer during single-turnover reduction of O2 is limited by proton transfer and can thus be used to study alterations in proton transfer rates. The exchange of residues along pathway 1 showed specific slowing of this proton-coupled electron transfer as well as changes in its pH dependence. Our results indicate that only pathway 1 is used to transfer protons in cNOR.

  16. Membrane topology of aspartate:alanine antiporter AspT from Comamonas testosteroni.

    PubMed

    Fujiki, Takashi; Nanatani, Kei; Nishitani, Kei; Yagi, Kyoko; Ohnishi, Fumito; Yoneyama, Hiroshi; Uchida, Takafumi; Nakajima, Tasuku; Abea, Keietsu

    2007-01-01

    We cloned the aspT gene encoding the L-aspartate:L-alanine antiporter AspTCt in Comamonas testosteroni genomic DNA. Analysis of the nucleotide sequence revealed that C. testosteroni has an asp operon containing aspT upstream of the l-aspartate 4-decarboxylase gene, and that the gene order of the asp operon of C. testosteroni is the inverse of that of Tetragenococcus halophilus. We used proteoliposomes to confirm the transport processes of AspTCt. To elucidate the two-dimensional structure of AspTCt, we analysed its membrane topology by means of alkaline phosphatase (PhoA) and beta-lactamase (BlaM) fusion methods. The fusion analyses revealed that AspTCt has seven transmembrane segments (TMs), a large cytoplasmic loop containing approximately 200 amino acid residues between TM4 and TM5, a cytoplasmic N-terminus, and a periplasmic C-terminus. These results suggest that the orientation of the N-terminus of AspTCt differs from that of tetragenococcal AspT, even though these two AspT orthologues catalyse the same transport reactions.

  17. Molecular Characterization and Substrate Specificity of Nitrobenzene Dioxygenase from Comamonas sp. Strain JS765

    PubMed Central

    Lessner, Daniel J.; Johnson, Glenn R.; Parales, Rebecca E.; Spain, Jim C.; Gibson, David T.

    2002-01-01

    Comamonas sp. strain JS765 can grow with nitrobenzene as the sole source of carbon, nitrogen, and energy. We report here the sequence of the genes encoding nitrobenzene dioxygenase (NBDO), which catalyzes the first step in the degradation of nitrobenzene by strain JS765. The components of NBDO were designated ReductaseNBZ, FerredoxinNBZ, OxygenaseNBZα, and OxygenaseNBZβ, with the gene designations nbzAa, nbzAb, nbzAc, and nbzAd, respectively. Sequence analysis showed that the components of NBDO have a high level of homology with the naphthalene family of Rieske nonheme iron oxygenases, in particular, 2-nitrotoluene dioxygenase from Pseudomonas sp. strain JS42. The enzyme oxidizes a wide range of substrates, and relative reaction rates with partially purified OxygenaseNBZ revealed a preference for 3-nitrotoluene, which was shown to be a growth substrate for JS765. NBDO is the first member of the naphthalene family of Rieske nonheme iron oxygenases reported to oxidize all of the isomers of mono- and dinitrotoluenes with the concomitant release of nitrite. PMID:11823201

  18. Oxidative Pathway for the Biodegradation of Nitrobenzene by Comamonas sp. Strain JS765

    PubMed Central

    Nishino, S. F.; Spain, J. C.

    1995-01-01

    Previous studies have shown that the biodegradation of nitrobenzene by Pseudomonas pseudoalcaligenes JS45 proceeds by the reduction of nitrobenzene through nitrosobenzene and hydroxylaminobenzene, followed by rearrangement to 2-aminophenol, which then undergoes meta ring cleavage. We report here the isolation of a Comamonas sp. that uses an oxidative pathway for the complete mineralization of nitrobenzene. The isolate, designated strain JS765, uses nitrobenzene as a sole source of carbon, nitrogen, and energy. Nitrobenzene-grown cells oxidized nitrobenzene, with the stoichiometric release of nitrite. Extracts of nitrobenzene-grown JS765 showed high levels of catechol 2,3-dioxygenase activity that were not abolished by heating the cell extracts to 60(deg)C for 10 min. The ring cleavage product had an absorbance maximum at 375 nm, consistent with that of 2-hydroxymuconic semialdehyde. Both NAD-dependent dehydrogenase and NAD-independent hydrolase activities towards 2-hydroxymuconic semialdehyde were induced in extracts of nitrobenzene-grown cells. Catechol accumulated in the reaction mixture when cells preincubated with 3-chlorocatechol were incubated with nitrobenzene. Conversion of nitrobenzene to catechol by induced cells in the presence of 3-chlorocatechol and (sup18)O(inf2) demonstrated the simultaneous incorporation of two atoms of oxygen, which indicated that the initial reaction was dioxygenation. The results indicate that the catabolic pathway involves an initial dioxygenase attack on nitrobenzene with the release of nitrite and formation of catechol, which is subsequently degraded by a meta cleavage pathway. PMID:16535050

  19. Oxidative pathway for the biodegradation of nitrobenzene by Comamonas sp. strain JS765

    SciTech Connect

    Nishino, S.F.; Spain, J.C.

    1995-06-01

    Previous studies have shown that the biodegradation of nitrobenzene by Pseudomonas pseudoalcaligenes JS45 proceeds by the reduction of nitrobenzene through nitrosobenzene and hydroxylaminobenzene, followed by rearrangement to 2-aminophenol, which then undergoes meta ring cleavage. We report here the isolation of a Comamonas sp. that uses an oxidative pathway for the complete mineralization of nitrobenzene. The isolate, designated strain JS765, uses nitrobenzene as a sole source of carbon, nitrogen, and energy. Nitrobenzene-grown cells oxidized nitrobenzene, with the stoichiometric release of nitrite. Extracts of nitrobenzene-grown JS765 showed high levels of catechol 2,3-dioxygenase activity that were not abolished by heating the cell extracts to 60{degrees}C for 10 min. The ring cleavage product had an absorbance maximum at 375 nm, consistent with that of 2-hydroxymuconic semialdehyde. Both NAD-dependent dehydrogenase and NAD-indipendent hydrolase activities towards 2-hydroxymuconic semialdehyde were induced in extracts of nitrobenzene-grown cells. Catechol accumulated in the reaction mixture when cells preincubated with 3-chloracatechol were incubated with nitrobenzene. Conversion of nitrobenzene to catechol by induced cells in the presence of 3-chlorocatechol and {sup 13}O{sub 2} demonstrated the simultaneous incorporation of two atoms of oxygen, which indicated that the initial reaction was dioxygenation. Their results indicate that the catabolic pathway involves an initial dioxygenase attack on nitrobenzene with the release of nitrite and formation of catechol, which is subsequently degraded by a meta cleavage pathway. 37 refs., 4 figs., 4 tabs.

  20. Pseudovibrio denitrificans strain Z143-1, a heptylprodigiosin-producing bacterium isolated from a Philippine tunicate.

    PubMed

    Sertan-de Guzman, Alice A; Predicala, Rey Z; Bernardo, Evelyn B; Neilan, Brett A; Elardo, Sheila P; Mangalindan, Gina C; Tasdemir, Deniz; Ireland, Chris M; Barraquio, Wilfredo L; Concepcion, Gisela P

    2007-12-01

    Microbial isolate Z143-1 found to be associated with an unidentified tunicate was characterized due to its significant antimicrobial activity. Z143-1 is similar to Pseudovibrio ascidiaceicola and Pseudovibrio denitrificans in morphological, physiological and biochemical characteristics, except for its ability to ferment glucose and produce a characteristic red pigment. Fatty acid methyl ester analysis revealed a predominance of the fatty acid 18:1 omega7c at 80.55%, at levels slightly lower than the Pseudovibrio denitrificans type strain DN34(T) (87.7%). The mol% G+C of Z143-1 is 54.02, relatively higher than the Pseudovibrio denitrificans type strain DN34(T) and Pseudovibrio ascidiaceicola with mol% G+C of 51.7 and 51.4, respectively. However, phylogenetic analysis of the 16S rRNA gene sequence of Z143-1 showed 100% similarity with the Pseudovibrio denitrificans type strain DN34(T). In this study, the bacterium Z143-1 is reported as a new strain of Pseudovibrio denitrificans. While there is no report of a secondary metabolite for Pseudovibrio denitrificans, Z143-1 produces the red pigment heptylprodigiosin, also known as 16-methyl-15-heptyl-prodiginine, which shows anti-Staphylococcus aureus activity.

  1. Interactive performances of betaine on the metabolic processes of Pseudomonas denitrificans.

    PubMed

    Xia, Wei; Peng, Wei-fu; Chen, Wei; Li, Kun-tai

    2015-02-01

    The performances of betaine on the metabolic processes of vitamin B12-producing Pseudomonas denitrificans were investigated in this paper. The results showed that betaine was an indispensable methyl-group donor for vitamin B12 biosynthesis, but large amounts of the extracellular glycine accompanied by betaine metabolism would impose a severe restriction on the cell growth of P. denitrificans. By further using a comparative metabolomics approach coupled with intracellular free amino acids analysis for the fermentation processes with betaine addition (10 g/l) or not, it was found that betaine could highly strengthen the formation of some key precursors and intermediates facilitating vitamin B12 biosynthesis, such as δ-aminolevulinic acid (ALA, the first precursor of vitamin B12), glutamate (an intermediate of ALA via C5 pathway), glycine (an intermediate of ALA via C4 pathway), and methionine (directly participating in the methylation reaction involved in vitamin B12 biosynthetic pathway). Therefore, the performances of betaine on P. denitrificans metabolic processes were not only serving as a decisive methyl-group donor for vitamin B12 biosynthesis, but also playing a powerfully promoting role in the generation of vitamin B12 precursors and intermediates.

  2. Cloning and characterization of a novel β-ketoacyl-ACP reductase from Comamonas testosteroni.

    PubMed

    Zhang, Hao; Ji, Ye; Wang, Yan; Zhang, Xiao; Yu, Yuanhua

    2015-06-05

    Comamonas testosteroni (C. testosteroni) is a gram negative bacterium which can use steroid as a carbon source and degrade steroid with about 20 special enzymes. Most of the enzymes are inducible enzymes. 3-Oxoacyl-ACP reductase (E.C. 1.1.1.100) alternatively known as β-ketoacyl-ACP reductase (BKR) is involved in fatty acid syntheses. DNA sequence comparison showed that BKR belongs to the short-chain alcohol dehydrogenase (SDR) family. Our results showed that BKR is necessary for the degradation of steroid hormones in C. testosteroni. The DNA fragment of the BKR gene was cloned into an expressional plasmid pET-15b. BKR protein was expressed with 6× His-tag on the N-terminus and the enzyme was purified with Ni-column. Antibodies against BKR were prepared and a new BKR quantitative ELISA was created in our laboratory. The purified BKR is a 30.6 kDa protein on SDS-PAGE. C. testosteroni was induced by testosterone, estradiol, estriol and cholesterol. The expression of BKR was detected with an ELISA. The result showed that the BKR expression could be induced by cholesterol and estriol but not by testosterone and estradiol. BKR gene knock-out mutant (M-C.T.) was prepared by homologous integration. High performance liquid chromatography (HPLC) was used to detect steroid hormone degradation in C. testosteroni ATCC11996 and BKR gene knock-out mutant. We proved that the M-C.T. eliminated of testosterone degradation. Degradations of cholesterol and estradiol were also decreased. We conclude that the novel BKR in C. testosteroni plays an important role in steroid degradation. This work provides some new information of SDR and steroid degradation in C. testosteroni.

  3. Involvement in Denitrification is Beneficial to the Biofilm Lifestyle of Comamonas testosteroni: A Mechanistic Study and Its Environmental Implications.

    PubMed

    Wu, Yichao; Shukal, Sudha; Mukherjee, Manisha; Cao, Bin

    2015-10-06

    Comamonas is one of the most abundant microorganisms in biofilm communities driving wastewater treatment. Little has been known about the role of this group of organisms and their biofilm mode of life. In this study, using Comamonas testosteroni as a model organism, we demonstrated the involvement of Comamonas biofilms in denitrification under bulk aerobic conditions and elucidated the influence of nitrate respiration on its biofilm lifestyle. Our results showed that C. testosteroni could use nitrate as the sole electron acceptor for anaerobic growth. Under bulk aerobic condition, biofilms of C. testosteroni were capable of reducing nitrate, and intriguingly, nitrate reduction significantly enhanced viability of the biofilm-cells and reduced cell detachment from the biofilms. Nitrate respiration was further shown to play an essential role in maintaining high cell viability in the biofilms. RNA-seq analysis, quantitative polymerase chain reaction, and liquid chromatography-mass spectrometry revealed a higher level of bis(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) in cells respiring on nitrate than those grown aerobically (1.3 × 10(-4) fmol/cell vs 7.9 × 10(-6) fmol/cell; P < 0.01). C-di-GMP is one universal signaling molecule that regulates the biofilm mode of life, and a higher c-di-GMP concentration reduces cell detachment from biofilms. Taking these factors together, this study reveals that nitrate reduction occurs in mature biofilms of C. testosteroni under bulk aerobic conditions, and the respiratory reduction of nitrate is beneficial to the biofilm lifestyle by providing more metabolic energy to maintain high viability and a higher level of c-di-GMP to reduce cell detachment.

  4. Nucleotide and derived amino acid sequences of the major porin of Comamonas acidovorans and comparison of porin primary structures.

    PubMed Central

    Gerbl-Rieger, S; Peters, J; Kellermann, J; Lottspeich, F; Baumeister, W

    1991-01-01

    The DNA sequence of the gene which codes for the major outer membrane porin (Omp32) of Comamonas acidovorans has been determined. The structural gene encodes a precursor consisting of 351 amino acid residues with a signal peptide of 19 amino acid residues. Comparisons with amino acid sequences of outer membrane proteins and porins from several other members of the class Proteobacteria and of the Chlamydia trachomatis porin and the Neurospora crassa mitochondrial porin revealed a motif of eight regions of local homology. The results of this analysis are discussed with regard to common structural features of porins. PMID:1848840

  5. Bioaugmentation of a sequencing batch biofilm reactor with Comamonas testosteroni and Bacillus cereus and their impact on reactor bacterial communities.

    PubMed

    Cheng, Zhongqin; Chen, Mei; Xie, Liqun; Peng, Lin; Yang, Maohua; Li, Mengying

    2015-02-01

    The immobilization of microorganisms is essential for efficient bioaugmentation systems. The performance of Bacillus cereus G5 as biofilm-forming bacteria and Comamonas testosteroni A3 a 3,5 dinitrobenzoic acid (DNB)-degrading strain] in laboratory-scale sequencing batch biofilm reactors (SBBRs) treating DNB synthetic wastewater has been examined. The microbial diversity in the reactors was also explored. The reactor R3 inoculated with B. cereus G5 and C. testosteroni A3 together not only improved the removal of contaminants, but also exhibited obvious resistance to shock loading with DNB during later operations. Pyrosequencing was used to evaluate bacterial communities in three reactors. Comamonas was predominant in the reactor R3, indicating the effect of G5 in promoting immobilization of A3 cells in biofilms. Those microbial resources, e.g.G5, which can stimulate the self-immobilization of the degrading bacteria offer a novel strategy for immobilization of degraders in bioaugmentation systems and show broader application prospects.

  6. Purification and some characteristics of nitric oxide reductase-containing vesicles from Paracoccus denitrificans.

    PubMed

    Hoglen, J; Hollocher, T C

    1989-05-05

    Nitric oxide reductase of Paracoccus denitrificans was purified, with the use of 3-[(3-cholamidopropyl)dimethylammonio]-2-hydroxy-1-propanesulfonate (CHAPSO) detergent, as membrane vesicles of apparent Mr = 2-3 x 10(6). Fifty percent of the protein was a peptide of Mr = 34,000. Further fractionation with sodium dodecyl sulfate (SDS) resulted in vesicles in which the peptide constituted 90-95% of the protein. This peptide, which is rich in Ala, Gly, Ser, Asx, and Glx, is considered to be the peptide of nitric oxide reductase. The CHAPSO- and SDS-fractionated preparations lost activity at 4 degrees C, pH 7.4, with half-times, respectively, of about 6 days and 4 h. Specific activities at 32 degrees C, pH 7.4, of about 0.33 mumol of NO x min-1 x mg-1 were realized after fractionation with CHAPSO in a phenazine methosulfate/ascorbate-based assay. The Km(NO) was less than or equal to 17 microM at pH 7.4. Rates decreased substantially below pH 5 and above pH 7.6. The preparations were free or almost free of cytochromes, exhibited otherwise no absorption bands in the visible region, contained no redox metals except for very small amounts of iron, were not inhibited by EDTA or some other common inhibitors of redox-metal enzymes, and were not observed to catalyze the reduction of nitrate, nitrite, or N2O. An absorption band at 274 nm in both the CHAPSO- and SDS-fractionated preparations was attributed to the presence of a solvent-soluble chromophore. N-Bromosuccinimide (NBS) inactivated the enzyme and bleached the chromophore both in the enzyme preparation and, after its purification, in 95% ethanol. NBS-inactivated enzyme could be reconstituted with purified chromophore, which alone seemed to have no nitric oxide reductase activity, but not with purified chromophore that had been reacted with NBS. Spectral changes interpretable as due to changes in redox state were not observed when enzyme was exposed to NO or certain reducing agents.

  7. Probing the Paracoccus denitrificans cytochrome c1 / c552 interaction by mutagenesis and fast kinetics†

    PubMed Central

    Janzon, Julia; Yuan, Quan; Malatesta, Francesco; Hellwig, Petra; Ludwig, Bernd; Durham, Bill; Millett, Francis

    2008-01-01

    Electron transfer (ET) between Paracoccus denitrificans cytochrome c1 and cytochrome c552 was studied using the soluble redox fragments cyt c1CF and cyt c552F. A new ruthenium cyt c552F derivative labeled at C23 (Ruz-23-c552F) was designed to measure rapid electron transfer with cyt c1CF in the physiological direction using flash photolysis. The bimolecular rate constant k12 decreased rapidly with ionic strength above 40 mM, consistent with a diffusional process guided by long-range electrostatic interactions between the two proteins. However, a new kinetic phase was detected below 35 mM ionic strength with the ruthenium photoexcitation technique in which k12 became very rapid (3 × 109 M−1s−1) and nearly independent of ionic strength, suggesting that the reaction became so fast that it was controlled by short-range diffusion along the protein surfaces guided by hydrophobic interactions. These results are consistent with a two-step model for formation of the final encounter complex. No intracomplex electron transfer between Ruz-23-c552F and c1CF was observed even at the lowest ionic strength, indicating that the dissociation constant of the complex was greater than 30 µM. On the other hand, the ruthenium-labeled yeast cytochrome c derivative Ruz-39-Cc formed a tight 1:1 complex with cyt c1CF at ionic strengths below 60 mM with an intracomplex electron transfer rate constant of 50,000 s−1. A group of cyt c1CF variants in the presumed docking site were generated based on information from the yeast cyt bc1/cyt c co-crystal structure. Kinetic analysis of cyt c1CF mutants located near the heme crevice provided preliminary identification of the interaction site for cyt c552F, and suggest that formation of the encounter complex is guided primarily by the overall electrostatic surface potential rather than by defined ions. PMID:19006325

  8. Influence of 3-Chloroaniline on the Biofilm Lifestyle of Comamonas testosteroni and Its Implications on Bioaugmentation

    PubMed Central

    Wu, Yichao; Mohanty, Anee; Chia, Wu Siang

    2016-01-01

    ABSTRACT Bioaugmentation has been frequently proposed in wastewater and soil treatment to remove toxic aromatic compounds. The performance of bioaugmentation is affected by a number of biological and environmental factors, including the interaction between the target pollutant and the augmented bacterial cells. In this study, using Comamonas testosteroni and 3-chloroaniline (3-CA) as the model organism and target pollutant, we explored the influence of toxic aromatic pollutants on the biofilm lifestyle of bacteria capable of degrading aromatic compounds toward a better understanding of cell-pollutant interaction in bioaugmentation. Our results showed that the exposure to 3-CA greatly reduced the retention of C. testosteroni cells in packed-bed bioreactors (from 22% to 15% after three pore volumes), which could be attributed to the altered bacterial motility and cell surface hydrophobicity. To further understand the molecular mechanisms, we employed an integrated genomic and transcriptomic analysis to examine the influence of 3-CA on the expression of genes important to the biofilm lifestyle of C. testosteroni. We found that exposure to 3-CA reduced the intracellular c-di-GMP level by downregulating the expression of genes encoding c-di-GMP synthases and induced massive cell dispersal from the biofilms. Our findings provide novel environmental implications on bioaugmentation, particularly in biofilm reactors, for the treatment of wastewater containing recalcitrant industrial pollutants. IMPORTANCE Bioaugmentation is a bioremediation approach that often has been described in the literature but has almost never been successfully applied in practice. Many biological and environmental factors influence the overall performance of bioaugmentation. Among these, the interaction between the target pollutant and the augmented bacterial cells is one of the most important factors. In this study, we revealed the influence of toxic aromatic pollutants on the biofilm lifestyle of

  9. Steady-State Oxygen Isotope Effects of N2O Production in Paracoccus denitrificans.

    PubMed

    Barford, Carol; Montoya, Joseph; Altabet, Mark; Mitchell, Ralph

    2017-03-21

    Knowledge of isotopic discrimination, or fractionation, by denitrifying bacteria can benefit agricultural fertilizer management, wastewater treatment, and other applications. However, the complexity of N transformation pathways in the environment and the sensitivity of denitrification to environmental conditions warrant better isotopic distinction between denitrification and other processes, especially for oxygen isotopes. Here, we present a dataset of δ(18)O measurements in continuous culture of Paracoccus denitrificans. The authors hope that it will be useful in further studies of N2O in the environment.

  10. Novel organization of catechol meta pathway genes in the nitrobenzene degrader Comamonas sp. JS765 and its evolutionary implication.

    PubMed

    He, Zhongqi; Parales, Rebecca E; Spain, Jim C; Johnson, Glenn R

    2007-02-01

    The catechol meta cleavage pathway is one of the central metabolic pathways for the degradation of aromatic compounds. A novel organization of the pathway genes, different from that of classical soil microorganisms, has been observed in Sphingomonas sp HV3 and Pseudomonas sp. DJ77. In a Comamonas sp. JS765, cdoE encoding catechol 2,3-dioxygenase shares a common ancestry only with tdnC of a Pseudomonas putida strain, while codG encoding 2-hydroxymuconic semialdehyde dehydrogenase shows a higher degree of similarity to those genes in classical bacteria. Located between cdoE and cdoG are several putative genes, whose functions are unknown. These genes are not found in meta pathway operons of other microorganisms with the exception of cdoX2, which is similar to cmpX in strain HV3. Therefore, the gene cluster in JS765 reveals a third type of gene organization of the meta pathway.

  11. Two variants of the assembly factor Surf1 target specific terminal oxidases in Paracoccus denitrificans.

    PubMed

    Bundschuh, Freya A; Hoffmeier, Klaus; Ludwig, Bernd

    2008-10-01

    Biogenesis of cytochrome c oxidase (COX) relies on a large number of assembly proteins, one of them being Surf1. In humans, the loss of Surf1 function is associated with Leigh syndrome, a fatal neurodegenerative disorder. In the soil bacterium Paracoccus denitrificans, homologous genes specifying Surf1 have been identified and located in two operons of terminal oxidases: surf1q is the last gene of the qox operon (coding for a ba(3)-type ubiquinol oxidase), and surf1c is found at the end of the cta operon (encoding subunits of the aa(3)-type cytochrome c oxidase). We introduced chromosomal single and double deletions for both surf1 genes, leading to significantly reduced oxidase activities in membrane. Our experiments on P. denitrificans surf1 single deletion strains show that both Surf1c and Surf1q are functional and act independently for the aa(3)-type cytochrome c oxidase and the ba(3)-type quinol oxidase, respectively. This is the first direct experimental evidence for the involvement of a Surf1 protein in the assembly of a quinol oxidase. Analyzing the heme content of purified cytochrome c oxidase, we conclude that Surf1, though not indispensable for oxidase assembly, is involved in an early step of cofactor insertion into subunit I.

  12. Achromobacter denitrificans strain SP1 efficiently remediates di(2-ethylhexyl)phthalate.

    PubMed

    Pradeep, S; Josh, M K Sarath; Binod, P; Devi, R Sudha; Balachandran, S; Anderson, Robin C; Benjamin, Sailas

    2015-02-01

    This study describes how Achromobacter denitrificans strain SP1, a novel isolate from heavily plastics-contaminated sewage sludge efficiently consumed the hazardous plasticizer, di(2-ethylhexyl)phthalate (DEHP) as carbon source supplemented in a simple basal salt medium (BSM). Response surface methodology was employed for the statistical optimization of the process parameters such as temperature (32°C), agitation (200 rpm), DEHP concentration (10 mM), time (72 h) and pH (8.0). At these optimized conditions, experimentally observed DEHP degradation was 63%, while the predicted value was 59.2%; and the correlation coefficient between them was 0.998, i.e., highly significant and fit to the predicted model. Employing GC-MS analysis, the degradation pathway was partially deduced with intermediates such as mono(2-ethylhexyl)phthalate and 2-ethyl hexanol. Briefly, this first report describes A. denitrificans strain SP1 as a highly efficient bacterium for completely remediating the hazardous DEHP (10 mM) in 96 h in BSM (50% consumed in 60 h), which offers great potentials for efficiently cleaning the DEHP-contaminated environments such as soil, sediments and water upon its deployment.

  13. Metabolic response of Alicycliphilus denitrificans strain BC toward electron acceptor variation.

    PubMed

    Oosterkamp, Margreet J; Boeren, Sjef; Plugge, Caroline M; Schaap, Peter J; Stams, Alfons J M

    2013-10-01

    Alicycliphilus denitrificans is a versatile, ubiquitous, facultative anaerobic bacterium. Alicycliphilus denitrificans strain BC can use chlorate, nitrate, and oxygen as electron acceptor for growth. Cells display a prolonged lag-phase when transferred from nitrate to chlorate and vice versa. Furthermore, cells adapted to aerobic growth do not easily use nitrate or chlorate as electron acceptor. We further investigated these responses of strain BC by differential proteomics, transcript analysis, and enzyme activity assays. In nitrate-adapted cells transferred to chlorate and vice versa, appropriate electron acceptor reduction pathways need to be activated. In oxygen-adapted cells, adaptation to the use of chlorate or nitrate is likely difficult due to the poorly active nitrate reduction pathway and low active chlorate reduction pathway. We deduce that the Nar-type nitrate reductase of strain BC also reduces chlorate, which may result in toxic levels of chlorite if cells are transferred to chlorate. Furthermore, the activities of nitrate reductase and nitrite reductase appear to be not balanced when oxygen-adapted cells are shifted to nitrate as electron acceptor, leading to the production of a toxic amount of nitrite. These data suggest that strain BC encounters metabolic challenges in environments with fluctuations in the availability of electron acceptors. All MS data have been deposited in the ProteomeXchange with identifier PXD000258.

  14. Nitrogen, carbon, and sulfur isotopic change during heterotrophic (Pseudomonas aureofaciens) and autotrophic (Thiobacillus denitrificans) denitrification reactions

    NASA Astrophysics Data System (ADS)

    Hosono, Takahiro; Alvarez, Kelly; Lin, In-Tian; Shimada, Jun

    2015-12-01

    In batch culture experiments, we examined the isotopic change of nitrogen in nitrate (δ15NNO3), carbon in dissolved inorganic carbon (δ13CDIC), and sulfur in sulfate (δ34SSO4) during heterotrophic and autotrophic denitrification of two bacterial strains (Pseudomonas aureofaciens and Thiobacillus denitrificans). Heterotrophic denitrification (HD) experiments were conducted with trisodium citrate as electron donor, and autotrophic denitrification (AD) experiments were carried out with iron disulfide (FeS2) as electron donor. For heterotrophic denitrification experiments, a complete nitrate reduction was accomplished, however bacterial denitrification with T. denitrificans is a slow process in which, after seventy days nitrate was reduced to 40% of the initial concentration by denitrification. In the HD experiment, systematic change of δ13CDIC (from - 7.7‰ to - 12.2‰) with increase of DIC was observed during denitrification (enrichment factor εN was - 4.7‰), suggesting the contribution of C of trisodium citrate (δ13C = - 12.4‰). No SO42 - and δ34SSO4 changes were observed. In the AD experiment, clear fractionation of δ13CDIC during DIC consumption (εC = - 7.8‰) and δ34SSO4 during sulfur use of FeS2-S (around 2‰), were confirmed through denitrification (εN = - 12.5‰). Different pattern in isotopic change between HD and AD obtained on laboratory-scale are useful to recognize the type of denitrification occurring in the field.

  15. Nitrogen, carbon, and sulfur isotopic change during heterotrophic (Pseudomonas aureofaciens) and autotrophic (Thiobacillus denitrificans) denitrification reactions.

    PubMed

    Hosono, Takahiro; Alvarez, Kelly; Lin, In-Tian; Shimada, Jun

    2015-12-01

    In batch culture experiments, we examined the isotopic change of nitrogen in nitrate (δ(15)NNO3), carbon in dissolved inorganic carbon (δ(13)CDIC), and sulfur in sulfate (δ(34)SSO4) during heterotrophic and autotrophic denitrification of two bacterial strains (Pseudomonas aureofaciens and Thiobacillus denitrificans). Heterotrophic denitrification (HD) experiments were conducted with trisodium citrate as electron donor, and autotrophic denitrification (AD) experiments were carried out with iron disulfide (FeS2) as electron donor. For heterotrophic denitrification experiments, a complete nitrate reduction was accomplished, however bacterial denitrification with T. denitrificans is a slow process in which, after seventy days nitrate was reduced to 40% of the initial concentration by denitrification. In the HD experiment, systematic change of δ(13)CDIC (from -7.7‰ to -12.2‰) with increase of DIC was observed during denitrification (enrichment factor εN was -4.7‰), suggesting the contribution of C of trisodium citrate (δ(13)C=-12.4‰). No SO4(2-) and δ(34)SSO4 changes were observed. In the AD experiment, clear fractionation of δ(13)CDIC during DIC consumption (εC=-7.8‰) and δ(34)SSO4 during sulfur use of FeS2-S (around 2‰), were confirmed through denitrification (εN=-12.5‰). Different pattern in isotopic change between HD and AD obtained on laboratory-scale are useful to recognize the type of denitrification occurring in the field.

  16. Achromobactor denitrificans SP1 produces pharmaceutically active 25C prodigiosin upon utilizing hazardous di(2-ethylhexyl)phthalate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Achromobacter denitrificans SP1 isolated from soil sludge heavily contaminated with plastic waste produced a novel pharmaceutically-active 25C prodigiosin analog during growth in a simple mineral salt medium supplemented with hazardous di(2-ethylhexyl)phthalate (DEHP) blended PVC plastics (in situ) ...

  17. The Rieske protein from Paracoccus denitrificans is inserted into the cytoplasmic membrane by the twin-arginine translocase.

    PubMed

    Bachmann, Julie; Bauer, Brigitte; Zwicker, Klaus; Ludwig, Bernd; Anderka, Oliver

    2006-11-01

    The Rieske [2Fe-2S] protein (ISP) is an essential subunit of cytochrome bc(1) complexes in mitochondrial and bacterial respiratory chains. Based on the presence of two consecutive arginines, it was argued that the ISP of Paracoccus denitrificans, a Gram-negative soil bacterium, is inserted into the cytoplasmic membrane via the twin-arginine translocation (Tat) pathway. Here, we provide experimental evidence that membrane integration of the bacterial ISP indeed relies on the Tat translocon. We show that targeting of the ISP depends on the twin-arginine motif. A strict requirement is established particularly for the second arginine residue (R16); conservative replacement of the first arginine (R15K) still permits substantial ISP transport. Comparative sequence analysis reveals characteristics common to Tat signal peptides in several bacterial ISPs; however, there are distinctive features relating to the fact that the presumed ISP Tat signal simultaneously serves as a membrane anchor. These differences include an elevated hydrophobicity of the h-region compared with generic Tat signals and the absence of an otherwise well-conserved '+5'-consensus motif lysine residue. Substitution of the +5 lysine (Y20K) compromises ISP export and/or cytochrome bc(1) stability to some extent and points to a specific role for this deviation from the canonical Tat motif. EPR spectroscopy confirms cytosolic insertion of the [2Fe-2S] cofactor. Mutation of an essential cofactor binding residue (C152S) decreases the ISP membrane levels, possibly indicating that cofactor insertion is a prerequisite for efficient translocation along the Tat pathway.

  18. Crystallization and preliminary X-ray characterization of chaperonin-60 from Paracoccus denitrificans

    NASA Astrophysics Data System (ADS)

    Fukami, Takaaki A.; Takasuga, Yoshio; Sumi, Masato; Yohda, Masafumi; Yoshida, Masasuke; Miki, Kunio

    1996-10-01

    Chaperonin-60 (cpn60) from Paracoccus denitrificans has been crystallized using polyethyleneglycol(PEG) 6000 and LiCl as precipitants. The crystals diffract up to 3.0 Å resolution by using synchrotron radiation. They belong to the tetragonal space group P4 22 12 with unit cell parameters of a = b = 284 Å, c = 152 Å. Seven subunit molecules of cpn60 seem to exist in the asymmetric unit of the crystal. A complete diffraction data set was collected using a Weissenberg camera system attached to the synchrotron radiation source and merged up to 3.2 Å resolution. Self-rotation functions calculated show the existence of a local 7-fold axis, suggesting the 7-fold symmetry ring assembly.

  19. Anaerobic, nitrate-dependent oxidation of pyrite nanoparticles by Thiobacillus denitrificans.

    PubMed

    Bosch, Julian; Lee, Keun-Young; Jordan, Guntram; Kim, Kyoung-Woong; Meckenstock, Rainer U

    2012-02-21

    Pyrite is a key mineral in the global biogeochemical cycles of sulfur and iron, yet its anaerobic microbial oxidation has eluded geochemists and microbiologists for decades. Recent reports indicated that anaerobic oxidation of pyrite is occurring, but the mechanism remains unclear. Here, we provide evidence for the capability of Thiobacillus denitrificans to anaerobically oxidize a putatively nanosized pyrite particle fraction with nitrate as electron acceptor. Nanosized pyrite was readily oxidized to ferric iron and sulfate with a rate of 10.1 μM h(-1). The mass balance of pyrite oxidation and nitrate reduction revealed a closed recovery of the electrons. This substantiates a further "missing lithotrophy" in the global cycles of sulfur and iron and emphasizes the high reactivity of nanominerals in the environment.

  20. Purification of Paracoccus denitrificans cytochrome c552 and sequence analysis of the gene.

    PubMed

    Turba, A; Jetzek, M; Ludwig, B

    1995-07-01

    Unlike mitochondria, many bacteria use a large repertoire of c-type cytochromes in different branches of their electron transport system. Among the many cytochromes c present in the soil bacterium Paracoccus denitrificans, a membrane-bound cytochrome (c552) has been suggested to mediate the electron transport between the cytochrome bc1 complex and cytochrome-c oxidase [Berry, E. A. & Trumpower, B. L. (1985) J. Biol. Chem. 260, 2458-2467]. We have purified this cytochrome from cytoplasmic membranes, and cloned and sequenced its gene, cycM. Sequence analysis reveals that, while its C-terminal portion is highly similar to type-I cytochromes c, its N-terminal part contains a hydrophobic segment providing membrane attachment. In addition, we present immunological evidence for its functional role in respiration.

  1. Cytochrome c oxidase from Paracoccus denitrificans in Triton X-100: aggregation state and kinetics.

    PubMed

    Bolli, R; Nałecz, K A; Azzi, A

    1986-08-01

    Cytochrome c oxidase from Paracoccus denitrificans was homogeneously dispersed in Triton X-100. Using gel exclusion chromatography and sucrose gradient centrifugation analysis a molecular weight of the detergent-protein complex of 155,000 was determined. After subtraction of the bound detergent (111 mol/mol heme aa3) a molecular weight of 85,000 resulted, which agreed well with the model of a monomer containing two subunits. This monomer showed high cytochrome c oxidase activity when measured spectrophotometrically in the presence of Triton X-100 (Vmax = 85 s-1). The molecular activity, plotted according to Eadie-Hofstee, was monophasic as a function of the cytochrome c concentration. A Km of 3.6 X 10(-6) M was evaluated, similar to the Km observed in the presence of dodecyl maltoside [Nałecz et al. (1985).

  2. Kinetic properties of ATP sulfurylase and APS kinase from Thiobacillus denitrificans.

    PubMed

    Gay, Sean C; Fribourgh, Jennifer L; Donohoue, Paul D; Segel, Irwin H; Fisher, Andrew J

    2009-09-01

    The Thiobacillus denitrificans genome contains two sequences corresponding to ATP sulfurylase (Tbd_0210 and Tbd_0874). Both genes were cloned and expressed protein characterized. The larger protein (Tbd_0210; 544 residues) possesses an N-terminal ATP sulfurylase domain and a C-terminal APS kinase domain and was therefore annotated as a bifunctional enzyme. But, the protein was not bifunctional because it lacked ATP sulfurylase activity. However, the enzyme did possess APS kinase activity and displayed substrate inhibition by APS. Truncated protein missing the N-terminal domain had <2% APS kinase activity suggesting the function of the inactive sulfurylase domain is to promote the oligomerization of the APS kinase domains. The smaller gene product (Tbd_0874; 402 residues) possessed strong ATP sulfurylase activity with kinetic properties that appear to be kinetically optimized for the direction of APS utilization and ATP+sulfate production, which is consistent with an enzyme that functions physiologically to produce inorganic sulfate.

  3. Oscillations of nitric oxide concentration in the perturbed denitrification pathway of Paracoccus denitrificans.

    PubMed Central

    Kucera, I

    1992-01-01

    The metabolism of nitric oxide in Paracoccus denitrificans has been studied using a Clark-type electrode. The uncoupler carbonyl cyanide m-chlorophenylhydrazone (CCCP) and the SH reagent N-ethylmaleimide, both of which released nitric oxide from cells respiring nitrite, were found to be efficient inhibitors of nitric oxide reductase activity. Control experiments with another uncoupler, pentachlorophenol, showed that the inhibitory effect of CCCP was not the result of a decrease in membrane potential. The denitrification pathway in cells with partly inhibited nitric oxide reductase, or in a reconstituted system containing purified nitric reductase and membrane vesicles, exhibited marked sustained oscillations of nitric oxide concentration. The occurrence of the oscillations was strictly dependent on the initial concentration of nitrite. The observed oscillatory kinetics is considered to reflect two regulatory signals destabilizing the denitrification pathway, namely the inhibition of nitric oxide reductase by nitric oxide and/or by nitrite. PMID:1325776

  4. Soil bacteria Pseudomonas putida and Alcaligenes xylosoxidans subsp. denitrificans inactivate triclosan in liquid and solid substrates.

    PubMed

    Meade, M J; Waddell, R L; Callahan, T M

    2001-10-16

    Triclosan is a broad-spectrum antimicrobial agent that has been incorporated into many household and medical products. Bacteria with high levels of triclosan resistance were isolated from compost, water, and soil samples. Two of these bacteria, Pseudomonas putida TriRY and Alcaligenes xylosoxidans subsp. denitrificans TR1, were able to use triclosan as a sole carbon source and clear particulate triclosan from agar. A decrease in triclosan concentration was measured by HPLC within 6 h of inoculation with strain TriRY and 24 h with strain TR1. Bioassays demonstrated that triclosan was inactivated in liquid cultures and/or embedded in plastic by the growth of strain TriRY and strain TR1, permitting the growth of triclosan-sensitive bacteria.

  5. Purification and properties of a dissimilatory nitrate reductase from Haloferax denitrificans

    NASA Technical Reports Server (NTRS)

    Hochstein, L. I.; Lang, F.

    1991-01-01

    A membrane-bound nitrate reductase (nitrite:(acceptor) oxidoreductase, EC 1.7.99.4) from the extremely halophilic bacterium Haloferax denitrificans was solubilized by incubating membranes in buffer lacking NaCl and purified by DEAE, hydroxylapatite, and Sepharose 6B gel filtration chromatography. The purified nitrate reductase reduced chlorate and was inhibited by azide and cyanide. Preincubating the enzyme with cyanide increased the extent of inhibition which in turn was intensified when dithionite was present. Although cyanide was a noncompetitive inhibitor with respect to nitrate, nitrate protected against inhibition. The enzyme, as isolated, was composed of two subunits (Mr 116,000 and 60,000) and behaved as a dimer during gel filtration (Mr 380,000). Unlike other halobacterial enzymes, this nitrate reductase was most active, as well as stable, in the absence of salt.

  6. Comparative Analysis of Denitrifying Activities of Hyphomicrobium nitrativorans, Hyphomicrobium denitrificans, and Hyphomicrobium zavarzinii

    PubMed Central

    Martineau, Christine; Mauffrey, Florian

    2015-01-01

    Hyphomicrobium spp. are commonly identified as major players in denitrification systems supplied with methanol as a carbon source. However, denitrifying Hyphomicrobium species are poorly characterized, and very few studies have provided information on the genetic and physiological aspects of denitrification in pure cultures of these bacteria. This is a comparative study of three denitrifying Hyphomicrobium species, H. denitrificans ATCC 51888, H. zavarzinii ZV622, and a newly described species, H. nitrativorans NL23, which was isolated from a denitrification system treating seawater. Whole-genome sequence analyses revealed that although they share numerous orthologous genes, these three species differ greatly in their nitrate reductases, with gene clusters encoding a periplasmic nitrate reductase (Nap) in H. nitrativorans, a membrane-bound nitrate reductase (Nar) in H. denitrificans, and one Nap and two Nar enzymes in H. zavarzinii. Concurrently with these differences observed at the genetic level, important differences in the denitrification capacities of these Hyphomicrobium species were determined. H. nitrativorans grew and denitrified at higher nitrate and NaCl concentrations than did the two other species, without significant nitrite accumulation. Significant increases in the relative gene expression levels of the nitrate (napA) and nitrite (nirK) reductase genes were also noted for H. nitrativorans at higher nitrate and NaCl concentrations. Oxygen was also found to be a strong regulator of denitrification gene expression in both H. nitrativorans and H. zavarzinii, although individual genes responded differently in these two species. Taken together, the results presented in this study highlight the potential of H. nitrativorans as an efficient and adaptable bacterium that is able to perform complete denitrification under various conditions. PMID:25979892

  7. Impact of biogenic substrates on sulfamethoxazole biodegradation kinetics by Achromobacter denitrificans strain PR1.

    PubMed

    Nguyen, P Y; Carvalho, Gilda; Reis, A C; Nunes, O C; Reis, M A M; Oehmen, A

    2017-03-11

    Pure cultures have been found to degrade pharmaceutical compounds. However, these cultures are rarely characterized kinetically at environmentally relevant concentrations. This study investigated the kinetics of sulfamethoxazole (SMX) degradation by Achromobacter denitrificans strain PR1 at a wide range of concentrations, from ng/L to mg/L, to assess the feasibility of using it for bioaugmentation purposes. Complete removal of SMX occurred for all concentrations tested, i.e., 150 mg/L, 500 µg/L, 20 µg/L, and 600 ng/L. The reaction rate coefficients (kbio) for the strain at the ng/L SMX range were: 63.4 ± 8.6, 570.1 ± 15.1 and 414.9 ± 124.2 L/g[Formula: see text]·day), for tests fed without a supplemental carbon source, with acetate, and with succinate, respectively. These results were significantly higher than the value reported for non-augmented activated sludge (0.41 L/(g [Formula: see text]·day) with hundreds of ng/L of SMX. The simultaneous consumption of an additional carbon source and SMX suggested that the energetic efficiency of the cells, boosted by the presence of biogenic substrates, was important in increasing the SMX degradation rate. The accumulation of 3-amino-5-methylisoxazole was observed as the only metabolite, which was found to be non-toxic. SMX inhibited the Vibrio fischeri luminescence after 5 min of contact, with EC50 values of about 53 mg/L. However, this study suggested that the strain PR1 still can degrade SMX up to 150 mg/L. The results of this work demonstrated that SMX degradation kinetics by A. denitrificans PR1 compares favorably with activated sludge and the strain is a potentially interesting organism for bioaugmentation for SMX removal from polluted waters.

  8. Cloning, expression and characterization of a putative 2,5-diketo-D-gluconic acid reductase in Comamonas testosteroni.

    PubMed

    Chen, Yuanan; Ji, Wei; Zhang, Hao; Zhang, Xiao; Yu, Yuanhua

    2015-06-05

    Aldo-keto reductases (AKRs) are a superfamily of soluble NAD(P)(H) oxidoreductases. The function of the enzymes is to reduce aldehydes and ketones into primary and secondary alcohols. We have cloned a 2,5-diketo-D-gluconic acid reductase (2,5DKGR) gene from Comamonas testosteroni (C. testosteroni) ATCC11996 (a Gram-negative bacterium which can use steroids as carbon and energy source) into plasmid pET-15b and over expressed in Escherichia coli BL21 (DE3). The protein was purified by His-tag Metal chelating affinity chromatography column. The 2,5-diketo-D-gluconic acid reductase (2,5DKGR) gene contains 1062 bp and could be translated into a protein of 353 amino acid residues. Three consensus sequences of the AKR superfamily are found as GxxxxDxAxxY, LxxxGxxxPxxGxG and LxxxxxxxxxDxxxxH. GxxxxDxAxxY is the active site, LxxxGxxxPxxGxG is the Cofactor-binding site for NAD(P)(H), LxxxxxxxxxDxxxxH is used for supporting the 3D structure. 2,5-diketo-D-gluconic acid reductase gene of C. testosteroni was knocked out and a mutant M-AKR was obtained. Compared to wild type C. testosteroni, degradations of testosterone, estradiol, oestrone and methyltestosterone in mutant M-AKR were decreased. Therefore, 2,5-diketo-D-gluconic acid reductase in C. testosteroni is involved in steroid degradation.

  9. Anaerobic, Nitrate-Dependent Oxidation of U(IV) Oxide Minerals by the Chemolithoautotrophic Bacterium Thiobacillus denitrificans

    PubMed Central

    Beller, Harry R.

    2005-01-01

    Under anaerobic conditions and at circumneutral pH, cells of the widely distributed, obligate chemolithoautotrophic bacterium Thiobacillus denitrificans oxidatively dissolved synthetic and biogenic U(IV) oxides (uraninite) in nitrate-dependent fashion: U(IV) oxidation required the presence of nitrate and was strongly correlated with nitrate consumption. This is the first report of anaerobic U(IV) oxidation by an autotrophic bacterium. PMID:15812053

  10. Anaerobic, Nitrate-Dependent Oxidation of U(IV) Oxide Minerals by the Chemolithoautotrophic Bacterium Thiobacillus denitrificans

    SciTech Connect

    Beller, H R

    2004-06-25

    Under anaerobic conditions and at circumneutral pH, cells of the widely-distributed, obligate chemolithoautotrophic bacterium Thiobacillus denitrificans oxidatively dissolved synthetic and biogenic U(IV) oxides (uraninite) in nitrate-dependent fashion: U(IV) oxidation required the presence of nitrate and was strongly correlated to nitrate consumption. This is the first report of anaerobic U(IV) oxidation by an autotrophic bacterium.

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

    PubMed

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

    2016-01-01

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

  12. Analyzing the catalytic role of active site residues in the Fe-type nitrile hydratase from Comamonas testosteroni Ni1.

    PubMed

    Martinez, Salette; Wu, Rui; Krzywda, Karoline; Opalka, Veronika; Chan, Hei; Liu, Dali; Holz, Richard C

    2015-07-01

    A strictly conserved active site arginine residue (αR157) and two histidine residues (αH80 and αH81) located near the active site of the Fe-type nitrile hydratase from Comamonas testosteroni Ni1 (CtNHase), were mutated. These mutant enzymes were examined for their ability to bind iron and hydrate acrylonitrile. For the αR157A mutant, the residual activity (k cat = 10 ± 2 s(-1)) accounts for less than 1% of the wild-type activity (k cat = 1100 ± 30 s(-1)) while the K m value is nearly unchanged at 205 ± 10 mM. On the other hand, mutation of the active site pocket αH80 and αH81 residues to alanine resulted in enzymes with k cat values of 220 ± 40 and 77 ± 13 s(-1), respectively, and K m values of 187 ± 11 and 179 ± 18 mM. The double mutant (αH80A/αH81A) was also prepared and provided an enzyme with a k cat value of 132 ± 3 s(-1) and a K m value of 213 ± 61 mM. These data indicate that all three residues are catalytically important, but not essential. X-ray crystal structures of the αH80A/αH81A, αH80W/αH81W, and αR157A mutant CtNHase enzymes were solved to 2.0, 2.8, and 2.5 Å resolutions, respectively. In each mutant enzyme, hydrogen-bonding interactions crucial for the catalytic function of the αCys(104)-SOH ligand are disrupted. Disruption of these hydrogen bonding interactions likely alters the nucleophilicity of the sulfenic acid oxygen and the Lewis acidity of the active site Fe(III) ion.

  13. Global Regulator IscR Positively Contributes to Antimonite Resistance and Oxidation in Comamonas testosteroni S44

    PubMed Central

    Liu, Hongliang; Zhuang, Weiping; Zhang, Shengzhe; Rensing, Christopher; Huang, Jun; Li, Jie; Wang, Gejiao

    2015-01-01

    Antimonial compounds can be found as a toxic contaminant in the environment. Knowledge on mechanisms of microbial Sb oxidation and its role in microbial tolerance are limited. Previously, we found that Comamonas testosteroni S44 was resistant to multiple heavy metals and was able to oxidize the toxic antimonite [Sb(III)] to the much less toxic antimonate [Sb(V)]. In this study, transposon mutagenesis was performed in C. testosteroni S44 to isolate genes responsible for Sb(III) resistance and oxidation. An insertion mutation into iscR, which regulates genes involved in the biosynthesis of Fe-S clusters, generated a strain called iscR-280. This mutant strain was complemented with a plasmid carrying iscR to generate strain iscR-280C. Compared to the wild type S44 and iscR-280C, strain iscR-280 showed lower resistance to Sb(III) and a lower Sb(III) oxidation rate. Strain iscR-280 also showed lower resistance to As(III), Cd(II), Cu(II), and H2O2. In addition, intracellular γ-glutamylcysteine ligase (γ-GCL) activity and glutathione (GSH) content were decreased in the mutated strain iscR-280. Real-time RT-PCR and lacZ fusion expression assay indicated that transcription of iscR and iscS was induced by Sb(III). Results of electrophoretic mobility shift assay (EMSA) and bacterial one-hybrid (B1H) system demonstrated a positive interaction between IscR and its promoter region. The diverse defective phenotypes and various expression patterns suggest a role for IscR in contributing to multi-metal(loid)s resistance and Sb(III) oxidation via Fe-S cluster biogenesis and oxidative stress protection. Bacterial Sb(III) oxidation is a detoxification reaction. PMID:26734615

  14. 4-Toluene sulfonate methyl-monooxygenase from Comamonas testosteroni T-2: purification and some properties of the oxygenase component.

    PubMed Central

    Locher, H H; Leisinger, T; Cook, A M

    1991-01-01

    Comamonas testosteroni T-2 synthesizes an inducible enzyme system that oxygenates 4-toluene sulfontate (TS) to 4-sulfobenzyl alcohol when grown in TS-salts medium. We purified this TS methyl-monooxygenase system (TSMOS) and found it to consist of two components. A monomeric, iron-sulfur flavoprotein (component B), which has been shown to act as a reductase in the 4-sulfobenzoate dioxygenase system of this organism (H. H. Locher, T. Leisinger, and A. M. Cook, Biochem. J. 274:833-842, 1991), carried electrons from NADH to component M, an oxygenase. This oxygenase had the UV-visible spectral characteristics of an iron-sulfur protein. Mrs of about 152,000 for the native oxygenase and of 43,000 under denaturing conditions indicated a homotri- or homotetrameric enzyme, whose N-terminal amino acids and amino acid composition were determined. The activity of the purified enzyme was enhanced about fivefold by the addition of Fe2+. In the presence of O2 and NADH, components B and M together catalyzed the stoichiometric transformation of TS or p-toluate to the corresponding alcohol. The reaction was confirmed as oxygenation of the methyl group by observation of an oxygen atom from 18O2 in carboxybenzyl alcohol. The substrate range of TSMOS included carboxylated analogs of TS (p- and m-toluates and 4-ethylbenzoate), whereas p-xylene, toluene, and p-cresol were not substrates. TSMOS also catalyzed demethylation; 4-methoxybenzoate was transformed to 4-hydroxybenzoate and formaldehyde. Images PMID:2050632

  15. Phospholipid Fatty Acids as Physiological Indicators of Paracoccus denitrificans Encapsulated in Silica Sol-Gel Hydrogels

    PubMed Central

    Trögl, Josef; Jirková, Ivana; Kuráň, Pavel; Akhmetshina, Elmira; Brovdyová, Tat′jána; Sirotkin, Alexander; Kirilina, Tatiana

    2015-01-01

    The phospholipid fatty acid (PLFA) content was determined in samples of Paracoccus denitrificans encapsulated in silica hydrogel films prepared from prepolymerized tetramethoxysilane (TMOS). Immediately after encapsulation the total PLFA concentration was linearly proportional to the optical density (600 nm) of the input microbial suspension (R2 = 0.99). After 7 days this relationship remained linear, but with significantly decreased slope, indicating a higher extinction of bacteria in suspensions of input concentration 108 cells/mL and higher. trans-Fatty acids, indicators of cytoplasmatic membrane disturbances, were below the detection limit. The cy/pre ratio (i.e., ratio of cyclopropylated fatty acids (cy17:0 + cy19:0) to their metabolic precursors (16:1ω7 + 18:1ω7)), an indicator of the transition of the culture to a stationary growth-phase, decreased depending on co-immobilization of nutrients in the order phosphate buffer > mineral medium > Luria Broth rich medium. The ratio, too, was logarithmically proportional to cell concentration. These results confirm the applicability of total PLFA as an indicator for the determination of living biomass and cy/pre ratio for determination of nutrient limitation of microorganisms encapsulated in sol-gel matrices. This may be of interest for monitoring of sol-gel encapsulated bacteria proposed as optical recognition elements in biosensor construction, as well as other biotechnological applications. PMID:25690547

  16. Phage resistance of a marine bacterium, Roseobacter denitrificans OCh114, as revealed by comparative proteomics.

    PubMed

    Huang, Chunxiao; Zhang, Yongyu; Jiao, Nianzhi

    2010-08-01

    Roseobacter is a dominant lineage in the marine environment. This group of bacteria is diverse in terms of both their phylogenetic composition and their physiological potential. Roseobacter denitrificans OCh114 is one of the most studied bacteria of the Roseobacter lineage. Recently, a lytic phage (RDJLPhi1) that infects this bacterium was isolated and a mutant strain (M1) of OCh114 that is resistant to RDJLPhi1 was also obtained. Here, we investigate the mechanisms supporting phage resistance of M1. Our results excluded the possibilities of several phage resistance mechanisms, including abortive infection, lysogeny, and the clustered regularly interspaced short palindromic repeats (CRISPRs) related mechanism. Adsorption kinetics assays revealed that adsorption inhibition might be a potential cause for the phage resistance of M1. Comparative proteomic analysis of M1 and OCh114 revealed significant changes in the membrane protein compliment of these bacteria. Five membrane proteins with important biological functions were significantly down-regulated in the phage-resistant M1. Meanwhile, several outer membrane porins with different modifications and an OmpA family domain protein were markedly up-regulated. We hypothesize that the down-regulated membrane proteins in M1 may serve as the potential phage receptors, whose absence prevented the adsorption of phage RDJLPhi1 to host cells and subsequent infection.

  17. Paracoccus denitrificans cytochrome c oxidase: a kinetic study on the two- and four-subunit complexes.

    PubMed

    Nicoletti; Witt; Ludwig; Brunori; Malatesta

    1998-07-20

    Cytochrome c oxidase from Paracoccus denitrificans has been purified in two different forms differing in polypeptide composition. An enzyme containing polypeptides I-IV is obtained when the purification procedure is performed in beta-d-dodecylmaltoside. If, however, Triton X-100 is used to purify the enzyme under otherwise identical conditions, an enzyme is obtained containing only subunits I-II. The two enzymes are undistinguishable by optical spectroscopy but show significant differences in the transient and steady-state time regimes, as studied by stopped-flow spectroscopy. The observed differences, however, are not due to removal of subunits III and IV, but rather to a specific effect of Triton X-100 which appears to affect cytochrome c binding. From these results it is not expected that subunits III and IV play any significant role in cytochrome c binding and, possibly, in the subsequent electron transfer processes. The results also suggest that both electrostatic and hydrophobic interactions may be important in the initial electron transfer process from cytochrome c.

  18. Studies on the Glutathione-Dependent Formaldehyde-Activating Enzyme from Paracoccus denitrificans

    PubMed Central

    Hopkinson, Richard J.; Leung, Ivanhoe K. H.; Smart, Tristan J.; Rose, Nathan R.; Henry, Luc; Claridge, Timothy D. W.; Schofield, Christopher J.

    2015-01-01

    Formaldehyde is a toxin and carcinogen that is both an environmental pollutant and an endogenous metabolite. Formaldehyde metabolism, which is probably essential for all aerobic cells, likely proceeds via multiple mechanisms, including via a glutathione-dependent pathway that is widely conserved in bacteria, plants and animals. However, it is unclear whether the first step in the glutathione-dependent pathway (i.e. formation of S-hydroxymethylglutathione (HMG)) is enzyme-catalysed. We report studies on glutathione-dependent formaldehyde-activating enzyme (GFA) from Paracoccus denitrificans, which has been proposed to catalyse HMG formation from glutathione and formaldehyde on the basis of studies using NMR exchange spectroscopy (EXSY). Although we were able to replicate the EXSY results, time course experiments unexpectedly imply that GFA does not catalyse HMG formation under standard conditions. However, GFA was observed to bind glutathione using NMR and mass spectrometry. Overall, the results reveal that GFA binds glutathione but does not directly catalyse HMG formation under standard conditions. Thus, it is possible that GFA acts as a glutathione carrier that acts to co-localise glutathione and formaldehyde in a cellular context. PMID:26675168

  19. Investigating the nitrification and denitrification kinetics under aerobic and anaerobic conditions by Paracoccus denitrificans ISTOD1.

    PubMed

    Medhi, Kristina; Singhal, Anjali; Chauhan, D K; Thakur, Indu Shekhar

    2017-03-16

    Municipal wastewater contains multiple nitrogen contaminants such as ammonia, nitrate and nitrite. Two heterotrophic nitrifier and aerobic denitrifiers, bacterial isolates ISTOD1 and ISTVD1 were isolated from domestic wastewater. On the basis of removal efficiency of ammonia, nitrate and nitrite under both aerobic and anaerobic conditions, ISTOD1 was selected and identified as Paracoccus denitrificans. Aerobically, NH4(+)-N had maximum specific nitrogen removal rate (Rxi) of 7.6g/gDCW/h and anaerobically, NO3(-)N showed Rxi of 2.5*10(-1)g/g DCW/h. Monod equation described the bioprocess kinetic coefficients, µmax and Ks, obtained by regression. Error functions were calculated to validate the Monod equation experimental data. Aerobic NO3(-)N showed the highest YW of 0.372mg DCW/mg NO3(-)N among the five conditions. ISTOD1 serves as a potential candidate for treating nitrogen rich wastewater using simultaneous nitrification and aerobic denitrification. It can be used in bioaugmentation studies under varied condition.

  20. Genome analysis and physiological comparison of Alicycliphilus denitrificans strains BC and K601T

    SciTech Connect

    Oosterkamp, Margreet J.; Veuskens, Teun; Saia, Flavia Talarico; Weelink, Sander A.B.; Goodwin, Lynne A.; Daligault, Hajnalka E.; Bruce, David; Detter, J. Chris; Tapia, Roxanne; Han, Cliff; Land, Miriam L; Hauser, Loren John; Langenhoff, A. M.; Gerritse, Jan; Van Berkel, Willem J. H.; Pieper, Dietmar; Junca, Howard; Smidt, Hauke; Schraa, Gosse; Davids, Mark; Schaap, Peter J; Plugge, Caroline M.; Stams, Alfons J. M.

    2013-01-01

    The genomes of the Betaproteobacteria Alicycliphilus denitrificans strains BC and K601T have been sequenced to get insight into the physiology of the two strains. Strain BC degrades benzene with chlorate as electron acceptor. The cyclohexanol-degrading denitrifying strain K601T is not able to use chlorate as electron acceptor, while strain BC cannot degrade cyclohexanol. The 16S rRNA sequences of strains BC and K601T are identical and the fatty acid methyl ester patterns of the strains are similar. Basic Local Alignment Search Tool (BLAST) analysis of predicted open reading frames of both strains showed most hits with Acidovorax sp. JS42, a bacterium that degrades nitro-aromatics. The genomes include strain-specific plasmids (pAlide201 in strain K601T and pAlide01 and pAlide02 in strain BC). Key genes of chlorate reduction in strain BC were located on a 120 kb megaplasmid (pAlide01), which was absent in strain K601T. Genes involved in cyclohexanol degradation were only found in strain K601T. Benzene and toluene are degraded via oxygenase-mediated pathways in both strains. Genes involved in the meta-cleavage pathway of catechol are present in the genomes of both strains. Strain BC also contains all genes of the ortho-cleavage pathway. The large number of mono- and dioxygenase genes in the genomes suggests that the two strains have a broader substrate range than known thus far.

  1. Interference of chlorate and chlorite with nitrate reduction in resting cells of Paracoccus denitrificans.

    PubMed

    Kucera, Igor

    2006-12-01

    When grown anaerobically on a succinate+nitrate (SN) medium, Paracoccus denitrificans forms the membrane-bound, cytoplasmically oriented, chlorate-reducing nitrate reductase Nar, while the periplasmic enzyme Nap is expressed during aerobic growth on butyrate+oxygen (BO) medium. Preincubation of SN cells with chlorate produced a concentration-dependent decrease in nitrate utilization, which could be ascribed to Nar inactivation. Toluenization rendered Nar less sensitive to chlorate, but more sensitive to chlorite, suggesting that the latter compound may be the true inactivator. The Nap enzyme of BO cells was inactivated by both chlorate and chlorite at concentrations that were at least two orders of magnitude lower than those shown to affect Nar. Partial purification of Nap resulted in insensitivity to chlorate and diminished sensitivity to chlorite. Azide was specific for SN cells in protecting nitrate reductase against chlorate attack, the protective effect of nitrate being more pronounced in BO cells. The results are discussed in terms of different metabolic activation of chlorine oxoanions in both types of cells, and limited permeation of chlorite across the cell membrane.

  2. The Online Morphology Control and Dynamic Studies on Improving Vitamin B12 Production by Pseudomonas denitrificans with Online Capacitance and Specific Oxygen Consumption Rate.

    PubMed

    Wang, Ze-Jian; Shi, Hui-Lin; Wang, Ping

    2016-07-01

    The relationship between the morphological character of Pseudomonas denitrificans and vitamin B12 synthesis based on real-time capacitance measurement and online specific oxygen consumption rate (Q O2) control was established for enhancing vitamin B12 production. Results demonstrated that the threshold Q O2 value lower than 2.0 mmol/gDCW/l would greatly stimulate the state transfer from the cell number growth phase to the cell elongation phase and promote rapid vitamin B12 biosynthesis, while the vitamin B12 biosynthesis rate could also be inhibited when the rate of cell's length-to-width ratio (ratio-LW) was higher than 10:1. Furthermore, the optimal morphology controlling strategy was achieved based on online Q O2 control, which increases the appropriate active cell numbers at the former phase, and then control the elongation of ratio-LW no more than 10:1 at the vitamin B12 biosynthesis phase. The maximal vitamin B12 production reached 239.7 mg/l at 168 h, which was improved by 14.7 % compared with the control (208 mg/l). This online controlling strategy would be effectively applied for improving industrial vitamin B12 fermentation.

  3. Capillary zone electrophoresis with field enhanced sample stacking as a tool for targeted metabolome analysis of adenine nucleotides and coenzymes in Paracoccus denitrificans.

    PubMed

    Musilová, Jindra; Sedlácek, Vojtech; Kucera, Igor; Glatz, Zdenek

    2009-07-01

    The main aim of this work was to demonstrate the applicability of capillary zone electrophoresis in combination with field enhanced sample stacking in targeted metabolome analyses of adenine nucleotides--AMP, ADP, ATP, coenzymes NAD(+), NADP(+) and their reduced forms in Paracoccus denitrificans. Sodium carbonate/hydrogencarbonate buffer (100 mM, pH 9.6) with the addition of beta-CD at a concentration of 10 mM was found to be an effective BGE for their separation within 20 min. Besides this, special attention was paid to the development of the procedure for the extraction of specific metabolites from the bacterium P. denitrificans. This procedure was not only optimised to achieve the highest metabolite yields but also to obtain a sample that was fully compatible with the online preconcetration strategy used. The developed methodology was finally applied in a study of the bacterium P. denitrificans at various stages of the active respiratory chain.

  4. Deduced amino acid sequence, functional expression, and unique enzymatic properties of the form I and form II ribulose bisphosphate carboxylase/oxygenase from the chemoautotrophic bacterium Thiobacillus denitrificans.

    PubMed

    Hernandez, J M; Baker, S H; Lorbach, S C; Shively, J M; Tabita, F R

    1996-01-01

    The cbbL cbbS and cbbM genes of Thiobacillus denitrificans, encoding form I and form II ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO), respectively, were found to complement a RubisCO-negative mutant of Rhodobacter sphaeroides to autotrophic growth. Endogenous T. denitrificans promoters were shown to function in R. sphaeroides, resulting in high levels of cbbL cbbS and cbbM expression in the R. sphaeroides host. This expression system provided high levels of both T. denitrificans enzymes, each of which was highly purified. The deduced amino acid sequence of the form I enzyme indicated that the large subunit was closely homologous to previously sequenced form I RubisCO enzymes from sulfur-oxidizing bacteria. The form I T. denitrificans enzyme possessed a very low substrate specificity factor and did not exhibit fallover, and yet this enzyme showed a poor ability to recover from incubation with ribulose 1,5-bisphosphate. The deduced amino acid sequence of the form II T. denitrificans enzyme resembled those of other form II RubisCO enzymes. The substrate specificity factor was characteristically low, and the lack of fallover and the inhibition by ribulose 1,5-bisphosphate were similar to those of form II RubisCO obtained from nonsulfur purple bacteria. Both form I and form II RubisCO from T. denitrificans possessed high KCO2 values, suggesting that this organism might suffer in environments containing low levels of dissolved CO2. These studies present the initial description of the kinetic properties of form I and form II RubisCO from a chemoautotrophic bacterium that synthesizes both types of enzyme.

  5. Deduced amino acid sequence, functional expression, and unique enzymatic properties of the form I and form II ribulose bisphosphate carboxylase/oxygenase from the chemoautotrophic bacterium Thiobacillus denitrificans.

    PubMed Central

    Hernandez, J M; Baker, S H; Lorbach, S C; Shively, J M; Tabita, F R

    1996-01-01

    The cbbL cbbS and cbbM genes of Thiobacillus denitrificans, encoding form I and form II ribulose 1,5-bisphosphate carboxylase/oxygenase (RubisCO), respectively, were found to complement a RubisCO-negative mutant of Rhodobacter sphaeroides to autotrophic growth. Endogenous T. denitrificans promoters were shown to function in R. sphaeroides, resulting in high levels of cbbL cbbS and cbbM expression in the R. sphaeroides host. This expression system provided high levels of both T. denitrificans enzymes, each of which was highly purified. The deduced amino acid sequence of the form I enzyme indicated that the large subunit was closely homologous to previously sequenced form I RubisCO enzymes from sulfur-oxidizing bacteria. The form I T. denitrificans enzyme possessed a very low substrate specificity factor and did not exhibit fallover, and yet this enzyme showed a poor ability to recover from incubation with ribulose 1,5-bisphosphate. The deduced amino acid sequence of the form II T. denitrificans enzyme resembled those of other form II RubisCO enzymes. The substrate specificity factor was characteristically low, and the lack of fallover and the inhibition by ribulose 1,5-bisphosphate were similar to those of form II RubisCO obtained from nonsulfur purple bacteria. Both form I and form II RubisCO from T. denitrificans possessed high KCO2 values, suggesting that this organism might suffer in environments containing low levels of dissolved CO2. These studies present the initial description of the kinetic properties of form I and form II RubisCO from a chemoautotrophic bacterium that synthesizes both types of enzyme. PMID:8550452

  6. Shewanella denitrificans sp. nov., a vigorously denitrifying bacterium isolated from the oxic-anoxic interface of the Gotland Deep in the central Baltic Sea.

    PubMed

    Brettar, Ingrid; Christen, Richard; Höfle, Manfred G

    2002-11-01

    Three strains of denitrifying estuarine bacteria, OS217(T), 05220 and OS226, were characterized for their physiological and biochemical features, fatty acid profiles and their phylogenetic position based on 16S rDNA sequences. The strains were isolated from the oxic-anoxic interface of an anoxic basin of the central Baltic Sea. Phylogenetic analyses of the 16S rDNA sequences revealed a clear affiliation with members of the genus Shewanella of the gamma-Proteobacteria. The closest sequence similarity was seen with Shewanella baltica, Shewanella putrefaciens and Shewanella frigidimarina (95-96%). The dominant fatty acids were 16:1omega7c, 15:0 iso, 16:0 and 13:0 iso. The G+C content of the DNA ranged from 46.8 to 48.1 mol%. The strains were unpigmented, polarly flagellated, mesophilic, facultatively anaerobic and able to use nitrate, nitrite and sulphite as electron acceptors. Growth was observed at salinities from 0 to 6%, with an optimum between 1 and 3%. According to their morphology, physiology, fatty acid composition and 16S rRNA sequences, the described bacteria fitted well into the genus Shewanella, but could be easily distinguished from the Shewanella species described to date. Because of their capacity for vigorous denitrification, the name Shewanella denitrificans sp. nov. is suggested for the Baltic isolates, for which the type strain is OS217(T) (= DSM 15013(T) = LMG 21692(T)).

  7. Genome-enabled studies of anaerobic, nitrate-dependent iron oxidation in the chemolithoautotrophic bacterium Thiobacillus denitrificans

    PubMed Central

    Beller, Harry R.; Zhou, Peng; Legler, Tina C.; Chakicherla, Anu; Kane, Staci; Letain, Tracy E.; A. O’Day, Peggy

    2013-01-01

    Thiobacillus denitrificans is a chemolithoautotrophic bacterium capable of anaerobic, nitrate-dependent U(IV) and Fe(II) oxidation, both of which can strongly influence the long-term efficacy of in situ reductive immobilization of uranium in contaminated aquifers. We previously identified two c-type cytochromes involved in nitrate-dependent U(IV) oxidation in T. denitrificans and hypothesized that c-type cytochromes would also catalyze Fe(II) oxidation, as they have been found to play this role in anaerobic phototrophic Fe(II)-oxidizing bacteria. Here we report on efforts to identify genes associated with nitrate-dependent Fe(II) oxidation, namely (a) whole-genome transcriptional studies [using FeCO3, Fe2+, and U(IV) oxides as electron donors under denitrifying conditions], (b) Fe(II) oxidation assays performed with knockout mutants targeting primarily highly expressed or upregulated c-type cytochromes, and (c) random transposon-mutagenesis studies with screening for Fe(II) oxidation. Assays of mutants for 26 target genes, most of which were c-type cytochromes, indicated that none of the mutants tested were significantly defective in nitrate-dependent Fe(II) oxidation. The non-defective mutants included the c1-cytochrome subunit of the cytochrome bc1 complex (complex III), which has relevance to a previously proposed role for this complex in nitrate-dependent Fe(II) oxidation and to current concepts of reverse electron transfer. A transposon mutant with a disrupted gene associated with NADH:ubiquinone oxidoreductase (complex I) was ~35% defective relative to the wild-type strain; this strain was similarly defective in nitrate reduction with thiosulfate as the electron donor. Overall, our results indicate that nitrate-dependent Fe(II) oxidation in T. denitrificans is not catalyzed by the same c-type cytochromes involved in U(IV) oxidation, nor have other c-type cytochromes yet been implicated in the process. PMID:24065960

  8. Respiratory Complex I in Bos taurus and Paracoccus denitrificans Pumps Four Protons across the Membrane for Every NADH Oxidized.

    PubMed

    Jones, Andrew J Y; Blaza, James N; Varghese, Febin; Hirst, Judy

    2017-03-24

    Respiratory complex I couples electron transfer between NADH and ubiquinone to proton translocation across an energy-transducing membrane to support the proton-motive force that drives ATP synthesis. The proton-pumping stoichiometry of complex I (i.e. the number of protons pumped for each two electrons transferred) underpins all mechanistic proposals. However, it remains controversial and has not been determined for any of the bacterial enzymes that are exploited as model systems for the mammalian enzyme. Here, we describe a simple method for determining the proton-pumping stoichiometry of complex I in inverted membrane vesicles under steady-state ADP-phosphorylating conditions. Our method exploits the rate of ATP synthesis, driven by oxidation of NADH or succinate with different sections of the respiratory chain engaged in catalysis as a proxy for the rate of proton translocation and determines the stoichiometry of complex I by reference to the known stoichiometries of complexes III and IV. Using vesicles prepared from mammalian mitochondria (from Bos taurus) and from the bacterium Paracoccus denitrificans, we show that four protons are pumped for every two electrons transferred in both cases. By confirming the four-proton stoichiometry for mammalian complex I and, for the first time, demonstrating the same value for a bacterial complex, we establish the utility of P. denitrificans complex I as a model system for the mammalian enzyme. P. denitrificans is the first system described in which mutagenesis in any complex I core subunit may be combined with quantitative proton-pumping measurements for mechanistic studies.

  9. Respiratory Complex I in Bos taurus and Paracoccus denitrificans Pumps Four Protons across the Membrane for Every NADH Oxidized*

    PubMed Central

    Jones, Andrew J. Y.; Blaza, James N.; Varghese, Febin; Hirst, Judy

    2017-01-01

    Respiratory complex I couples electron transfer between NADH and ubiquinone to proton translocation across an energy-transducing membrane to support the proton-motive force that drives ATP synthesis. The proton-pumping stoichiometry of complex I (i.e. the number of protons pumped for each two electrons transferred) underpins all mechanistic proposals. However, it remains controversial and has not been determined for any of the bacterial enzymes that are exploited as model systems for the mammalian enzyme. Here, we describe a simple method for determining the proton-pumping stoichiometry of complex I in inverted membrane vesicles under steady-state ADP-phosphorylating conditions. Our method exploits the rate of ATP synthesis, driven by oxidation of NADH or succinate with different sections of the respiratory chain engaged in catalysis as a proxy for the rate of proton translocation and determines the stoichiometry of complex I by reference to the known stoichiometries of complexes III and IV. Using vesicles prepared from mammalian mitochondria (from Bos taurus) and from the bacterium Paracoccus denitrificans, we show that four protons are pumped for every two electrons transferred in both cases. By confirming the four-proton stoichiometry for mammalian complex I and, for the first time, demonstrating the same value for a bacterial complex, we establish the utility of P. denitrificans complex I as a model system for the mammalian enzyme. P. denitrificans is the first system described in which mutagenesis in any complex I core subunit may be combined with quantitative proton-pumping measurements for mechanistic studies. PMID:28174301

  10. A cytochrome ba3 functions as a quinol oxidase in Paracoccus denitrificans. Purification, cloning, and sequence comparison.

    PubMed

    Richter, O M; Tao, J S; Turba, A; Ludwig, B

    1994-09-16

    A quinol oxidase has been purified from the cytoplasmic membrane of Paracoccus denitrificans; its heme composition and CO binding properties identify it as a cytochrome ba3. On SDS gels, the purified enzyme complex is separated into five polypeptides. Using partial peptide sequence information for subunit II, the gene locus has been cloned and sequenced. In a typical operon pattern, four genes were identified: qoxA, -B, -C, and -D, coding for subunits II, I, III, and IV. DNA-derived amino acid sequence comparisons reveal extensive similarities to other members of the terminal oxidase superfamily.

  11. Plasmid pCBI carries genes for anaerobic benzoate catabolism in Alcaligenes xylosoxidans subsp. denitrificans PN-1.

    PubMed Central

    Blake, C K; Hegeman, G D

    1987-01-01

    Pseudomonas sp. strain PN-1 is reclassified as Alcaligenes xylosoxidans subsp. denitrificans PN-1. Strain PN-1 is a gram-negative, rod-shaped organism, is motile by means of lateral flagella, is oxidase positive, and does not ferment sugars. Plasmid pCBI, carrying genes for the anaerobic degradation of benzoate in strain PN-1, is 17.4 kilobase pairs in length and is transmissible to a number of denitrifying Pseudomonas aeruginosa and Pseudomonas stutzeri strains. A restriction endonuclease map was constructed. PMID:2822651

  12. Construction of a Specialized Cloning Strain of E. Coli for the Nitrate Reductase Genes of Haloferax Denitrificans

    NASA Technical Reports Server (NTRS)

    Johnson, Emmett

    1999-01-01

    This is the final report on Joint Research Interchange (NCC2-5011) "Construction of a Specialized Cloning Strain of E.. coli for the Nitrate Reductase Genes of Haloferax denitrificans." Originally the award was 11/l/93-10/31/95, but there were no-cost extensions made, because of a year Sabbatical at the Pasteur Institute in Paris and other leaves of 3 months each at the Pasteur Institute, during which work could not be done on this project, which extended the closing date to 10/30/98.

  13. Characterization of the p-toluenesulfonate operon tsaMBCD and tsaR in Comamonas testosteroni T-2.

    PubMed Central

    Junker, F; Kiewitz, R; Cook, A M

    1997-01-01

    Comamonas testosteroni T-2 uses a standard, if seldom examined, attack on an aromatic compound and oxygenates the side chain of p-toluenesulfonate (TS) (or p-toluenecarboxylate) to p-sulfobenzoate (or terephthalate) prior to complete oxidation. The expression of the first three catabolic enzymes in the pathway, the TS methyl-monooxygenase system (comprising reductase B and oxygenase M; TsaMB), p-sulfobenzyl alcohol dehydrogenase (TsaC), and p-sulfobenzaldehyde dehydrogenase (TsaD), is coregulated as regulatory unit R1 (H. R. Schlafli Oppenberg, G. Chen, T. Leisinger, and A. M. Cook, Microbiology [Reading] 141:1891-1899, 1995). The components of the oxygenase system were repurified, and the N-terminal amino acid sequences were confirmed and extended. An internal sequence of TsaM was obtained, and the identity of the [2Fe-2S] Rieske center was confirmed by electron paramagnetic resonance spectroscopy. We purified both dehydrogenases (TsaC and TsaD) and determined their molecular weights and N-terminal amino acid sequences. Oligonucleotides derived from the partial sequences of TsaM were used to identify cloned DNA from strain T-2, and about 6 kb of contiguous cloned DNA was sequenced. Regulatory unit R1 was presumed to represent a four-gene operon (tsaMBCD) which was regulated by the LysR-type regulator, TsaR, encoded by a deduced one-gene transcriptional unit. The genes for the inducible TS transport system were not at this locus. The oxygenase system was confirmed to be a class IA mononuclear iron oxygenase, and class IA can now be seen to have two evolutionary groups, the monooxygenases and the dioxygenases, though the divergence is limited to the oxygenase components. The alcohol dehydrogenase TsaC was confirmed to belong to the short-chain, zinc-independent dehydrogenases, and the aldehyde dehydrogenase TsaD was found to resemble several other aldehyde dehydrogenases. The operon and its putative regulator are compared with units of the TOL plasmid. PMID:9006050

  14. Identification and isolation of a regulator protein for 3,17β-HSD expressional regulation in Comamonas testosteroni.

    PubMed

    Wu, Yin; Huang, Pu; Xiong, Guangming; Maser, Edmund

    2015-06-05

    Comamonas testosteroni (C. testosteroni) is able to catabolize a variety of steroids and polycyclic aromatic hydrocarbons. 3,17β-Hydroxysteroid dehydrogenase (3,17β-HSD) from C. testosteroni is a member of the short-chain dehydrogenase/reductase (SDR) superfamily. It is an inducible and key enzyme in steroid degradation. Elucidating the mechanism of 3,17β-HSD gene (βhsd) regulation may help us to generate prospective C. testosteroni mutants for bioremediation. The genome of C. testosteroni ATCC11996 was sequenced in our previous work. Upon examining the genome with bioinformatics tools, a gene (brp) coding for a regulator protein (BRP) for 3,17β-HSD expression was found upstream of the βhsd gene. A Blast search revealed high identities to a nucleotide binding protein with unknown function in other bacteria. Two potential promoters and two repeat sequences (RS, 16 bp), spaced to each other by 1661 bp, were also found upstream of the βhsd gene C. testosteroni. The brp gene was cloned into plasmid pK18 and pET-15b, expressed in Escherichia coli, and the recombinant BRP protein was purified on a Ni-column. In addition, a brp gene knock-out mutant of C. testosteroni was prepared. These knock-out mutants showed an enhanced expression of both the βhsd gene and the hsdA gene (the latter coding for 3α-HSD/CR) in the presence of testosterone. To characterize the BRP functional DNA domain, different fragments of the βhsd upstream regulatory region were tested in a cotransformation system. Our data reveal that the βhsd gene undergoes complex regulation involving the two promoters, a loop structure via the two repeat sequences, and the steroid testosterone. Furthermore, a proximal repressor gene for βhsd expression, phaR, had been identified in our previous investigations. The exact interplay between all these factors will be determined in future experiments.

  15. Preparation of a one-subunit cytochrome oxidase from Paracoccus denitrificans: spectral analysis and enzymatic activity.

    PubMed

    Müller, M; Schlapfer, B; Azzi, A

    1988-09-20

    Cytochrome c oxidase was isolated from Paracoccus denitrificans as a two-subunit enzyme. Chymotrypsin-catalyzed proteolysis reduced the molecular weight of each subunit by about 8000. The spectral properties of this preparation, as well as its Km for cytochrome c(1.7 muM), remained unchanged with respect to the native enzyme. Vmax was reduced by about 55% when assayed in Triton X-100 or in Triton X-100 supplemented with asolectin. Following further proteolysis by Staphylococcus aureus V8 protease, subunit I remained unchanged as judged by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, whereas subunit II was split into small peptides. These were removed by ion-exchange high-performance liquid chromatography. The one-subunit enzyme had an apparent molecular weight of 43,000. The reduction of molecular weight was also confirmed by the diminution of the ultraviolet/Soret absorption ratio. This value was 1.8-2.1 for the native enzyme and 1.3-1.5 for the one-subunit enzyme. The spectral properties (including the spectrum CO reduced minus reduced) were not modified by the proteolytic treatment, indicating that cytochromes a and a3 were present in equal amounts. The lack of spectral alteration and the known close association of the copper B atom with cytochrome a3 suggest that copper B is also contained within the one-subunit enzyme. The Km of the one-subunit oxidase was similar to that of the two-subunit enzyme; Vmax was decreased by about 50%. The activity of the one-subunit oxidase had a salt-dependent maximum at 30 mM KCl, almost identical with that of the undigested enzyme, and was inhibited by micromolar concentrations of KCN.

  16. Comparative resonance Raman study of cytochrome c oxidase from beef heart and Paracoccus denitrificans.

    PubMed

    Heibel, G E; Hildebrandt, P; Ludwig, B; Steinrücke, P; Soulimane, T; Buse, G

    1993-10-12

    Well-resolved, Soret band excited resonance Raman spectra were measured from the fully oxidized and fully reduced cytochrome c oxidase from beef heart and Paracoccus denitrificans. The vibrational patterns in the marker band region (1450-1700 cm-1) were analyzed, and a complete assignment of heme a and heme a3 vibrational modes is presented, permitting a detailed structural comparison of the mammalian and bacterial enzymes. Similar frequencies of the porphyrin modes for the reduced heme a and the reduced and oxidized heme a3 are found, indicating a close relationship of the ground-state conformations in all oxidase species studied. In oxidized heme a, however, significant frequency differences are observed and interpreted in terms of a ruffled porphyrin structure in the three- and two-subunit forms of the Paracoccus enzyme compared to the planar heme a of beef heart oxidase. The structural distortions, which also perturb the conformation of the formyl substituent and its electronic coupling with the porphyrin, reflect the specific heme-protein interactions at heme a. Since in the fully reduced state heme a appears to be largely planar in all oxidase species, the redox-linked conformational transition requires a more drastic rearrangement of the heme a-protein interactions in the bacterial than in the mammalian oxidase. For both heme a and heme a3 in the reduced state and for heme a3 in the oxidize state, frequency, intensity, and bandwidth differences of the formyl stretching vibration and intensity differences of some porphyrin modes are noted between the three oxidase forms. The same modes are also affected by quaternary structure changes in the bovine oxidase caused by different detergents and isolation procedures. These effects are attributed to differences of the dielectric properties of the heme environment, due to subtle structural changes in the heme pockets, induced by protein-protein interactions of subunit III with subunits I and/or II.

  17. Cloning, expression and characterization of D-aminoacylase from Achromobacter xylosoxidans subsp. denitrificans ATCC 15173.

    PubMed

    Wang, Wei; Xi, Huange; Bi, Qirui; Hu, Ying; Zhang, Yang; Ni, Mengxiang

    2013-07-19

    D-Aminoacylase catalyzes the conversion of N-acyl-D-amino acids to d-amino acids and fatty acids. The aim of this study was to identify the D-aminoacylase gene from Achromobacter xylosoxidans subsp. denitrificans ATCC 15173 and investigate the biochemical characterization of the enzyme. A previously uncharacterized D-aminoacylase gene (ADdan) from this organism was cloned and sequenced. The open reading frame (ORF) of ADdan was 1467 bp in size encoding a 488-amino acid polypeptide. ADdan, with a high amino acid similarity to N-acyl-D-aspartate amidohydrolase from Alcaligenes A6, showed relatively low sequence similarities to other characterized D-aminoacylases. The recombinant ADdan protein was expressed in Escherichia coli BL21 (DE3) using pET-28a with a T7 promoter. The enzyme was purified in a single chromatographic step using nickel affinity gel column. The molecular mass of the expressed protein, calculated by SDS-PAGE, was about 52 kDa. The purified ADdan showed optimal activity at pH 8.0 and 50°C, and was stable at pH 6.0-8.0 and up to 45°C. Its activity was inhibited by Cu(2+), Fe(2+), Ca(2+), Mn(2+), Ni(2+), Zn(2+) and Hg(2+), whereas Mg(2+) had no significant influence on this recombinant D-aminoacylase. This is the first report on the characterization of D-aminoacylase with activity towards both N-acyl derivatives of neutral D-amino acids and N-acyl-D-aspartate. The characteristics of ADdan could prove to be of interest in industrial production of D-amino acids.

  18. Kerstersia gyiorum gen. nov., sp. nov., a novel Alcaligenes faecalis-like organism isolated from human clinical samples, and reclassification of Alcaligenes denitrificans Rüger and Tan 1983 as Achromobacter denitrificans comb. nov.

    PubMed

    Coenye, Tom; Vancanneyt, Marc; Cnockaert, Margo C; Falsen, Enevold; Swings, Jean; Vandamme, Peter

    2003-11-01

    A polyphasic taxonomic study was performed on nine isolates recovered from various human clinical samples. Phenotypically, these isolates resembled Alcaligenes faecalis. Whole-cell protein analysis distinguished two different species, and this was confirmed by DNA-DNA hybridizations. Cellular fatty acid analysis and 16S rDNA sequence analysis indicated that these isolates were related to the genera Alcaligenes, Bordetella, Achromobacter and Pigmentiphaga and belonged to the family Alcaligenaceae. On the basis of the results of this study, the organisms were classified in a novel genus, Kerstersia gen. nov. This genus comprises one species, Kerstersia gyiorum sp. nov. (type strain LMG 5906(T)=API 184-2-84(T)=CCUG 47000(T)), and several unnamed isolates. The DNA G+C content of members of the genus Kerstersia is between 61.5 and 62.9 mol%. On the basis of previously published DNA-DNA hybridization results and data from chemotaxonomic studies, it is proposed that Alcaligenes denitrificans Rüger and Tan 1983 be reclassified as Achromobacter denitrificans comb. nov.

  19. Assembly of respiratory complexes I, III, and IV into NADH oxidase supercomplex stabilizes complex I in Paracoccus denitrificans.

    PubMed

    Stroh, Anke; Anderka, Oliver; Pfeiffer, Kathy; Yagi, Takao; Finel, Moshe; Ludwig, Bernd; Schägger, Hermann

    2004-02-06

    Stable supercomplexes of bacterial respiratory chain complexes III (ubiquinol:cytochrome c oxidoreductase) and IV (cytochrome c oxidase) have been isolated as early as 1985 (Berry, E. A., and Trumpower, B. L. (1985) J. Biol. Chem. 260, 2458-2467). However, these assemblies did not comprise complex I (NADH:ubiquinone oxidoreductase). Using the mild detergent digitonin for solubilization of Paracoccus denitrificans membranes we could isolate NADH oxidase, assembled from complexes I, III, and IV in a 1:4:4 stoichiometry. This is the first chromatographic isolation of a complete "respirasome." Inactivation of the gene for tightly bound cytochrome c552 did not prevent formation of this supercomplex, indicating that this electron carrier protein is not essential for structurally linking complexes III and IV. Complex I activity was also found in the membranes of mutant strains lacking complexes III or IV. However, no assembled complex I but only dissociated subunits were observed following the same protocols used for electrophoretic separation or chromatographic isolation of the supercomplex from the wild-type strain. This indicates that the P. denitrificans complex I is stabilized by assembly into the NADH oxidase supercomplex. In addition to substrate channeling, structural stabilization of a membrane protein complex thus appears as one of the major functions of respiratory chain supercomplexes.

  20. Cytochrome cb-type nitric oxide reductase with cytochrome c oxidase activity from Paracoccus denitrificans ATCC 35512.

    PubMed

    Fujiwara, T; Fukumori, Y

    1996-04-01

    A highly active nitric oxide reductase was purified from Paracoccus denitrificans ATCC 35512, formerly named Thiosphaera pantotropha, which was anaerobically cultivated in the presence of nitrate. The enzyme was composed of two subunits with molecular masses of 34 and 15 kDa and contained two hemes b and one heme c per molecule. Copper was not found in the enzyme. The spectral properties suggested that one of the two hemes b and heme c were in six-coordinated low-spin states and another heme b was in a five-coordinated high-spin state and reacted with carbon monoxide. The enzyme showed high cytochrome c-nitric oxide oxidoreductase activity and formed nitrous oxide from nitric oxide with the expected stoichiometry when P. denitrificans ATCC 35512 ferrocytochrome c-550 was used as the electron donor. The V max and Km values for nitric oxide were 84 micromol of nitric oxide per min/mg of protein and 0.25 microM, respectively. Furthermore, the enzyme showed ferrocytochrome c-550-O2 oxidoreductase activity with a V max of 8.4 micromol of O2 per min/mg of protein and a Km value of 0.9 mM. Both activities were 50% inhibited by about 0.3 mM KCN.

  1. Enzymatic properties, evidence for in vivo expression, and intracellular localization of shewasin D, the pepsin homolog from Shewanella denitrificans.

    PubMed

    Leal, Ana Rita; Cruz, Rui; Bur, Daniel; Huesgen, Pitter F; Faro, Rosário; Manadas, Bruno; Wlodawer, Alexander; Faro, Carlos; Simões, Isaura

    2016-03-31

    The widespread presence of pepsin-like enzymes in eukaryotes together with their relevance in the control of multiple biological processes is reflected in the large number of studies published so far for this family of enzymes. By contrast, pepsin homologs from bacteria have only recently started to be characterized. The work with recombinant shewasin A from Shewanella amazonensis provided the first documentation of this activity in prokaryotes. Here we extend our studies to shewasin D, the pepsin homolog from Shewanella denitrificans, to gain further insight into this group of bacterial peptidases that likely represent ancestral versions of modern eukaryotic pepsin-like enzymes. We demonstrate that the enzymatic properties of recombinant shewasin D are strongly reminiscent of eukaryotic pepsin homologues. We determined the specificity preferences of both shewasin D and shewasin A using proteome-derived peptide libraries and observed remarkable similarities between both shewasins and eukaryotic pepsins, in particular with BACE-1, thereby confirming their phylogenetic proximity. Moreover, we provide first evidence of expression of active shewasin D in S. denitrificans cells, confirming its activity at acidic pH and inhibition by pepstatin. Finally, our results revealed an unprecedented localization for a family A1 member by demonstrating that native shewasin D accumulates preferentially in the cytoplasm.

  2. Efficient simultaneous adsorption-biodegradation of high-concentrated N,N-dimethylformamide from water by Paracoccus denitrificans-graphene oxide microcomposites

    NASA Astrophysics Data System (ADS)

    Zheng, Yuan; Chen, Dongyun; Li, Najun; Xu, Qingfeng; Li, Hua; He, Jinghui; Lu, Jianmei

    2016-02-01

    Water contamination becomes one of the most pervasive environmental issues all over the world in recent years. In this paper, the functionalization of graphene oxide (GO) with copolymers containing methacrylic acid (MAA) and butyl methacrylate (BMA) was investigated to prepare a new microcomposite material (PGO) via free radical solution polymerization. PGO was used for the adsorption of N,N-dimethylformamide (DMF) from aqueous solution by utilizing the characteristics of ultralarge surface and the Van der Waals force between DMF molecules and polymers on the surface of PGO. Besides, PGO was used not only a high-capable adsorbent but also a carrier for the immobilization of Paracoccus denitrificans cells in the treatment of high-concentrated DMF. Bacterial cells could immobilized on the PGO (PGO@P. denitrificans) stably by covalent coupling process after acclimatization and high-concentrated DMF (2000 mg/L) could be removed completely and relatively rapidly from aqueous solutions by the simultaneous adsorption-biodegradation (SAB) process of PGO@P. denitrificans. Furthermore, the excellent recycle performance of PGO@P. denitrificans made the whole process more economical and practical.

  3. Efficient simultaneous adsorption-biodegradation of high-concentrated N,N-dimethylformamide from water by Paracoccus denitrificans-graphene oxide microcomposites

    PubMed Central

    Zheng, Yuan; Chen, Dongyun; Li, Najun; Xu, Qingfeng; Li, Hua; He, Jinghui; Lu, Jianmei

    2016-01-01

    Water contamination becomes one of the most pervasive environmental issues all over the world in recent years. In this paper, the functionalization of graphene oxide (GO) with copolymers containing methacrylic acid (MAA) and butyl methacrylate (BMA) was investigated to prepare a new microcomposite material (PGO) via free radical solution polymerization. PGO was used for the adsorption of N,N-dimethylformamide (DMF) from aqueous solution by utilizing the characteristics of ultralarge surface and the Van der Waals force between DMF molecules and polymers on the surface of PGO. Besides, PGO was used not only a high-capable adsorbent but also a carrier for the immobilization of Paracoccus denitrificans cells in the treatment of high-concentrated DMF. Bacterial cells could immobilized on the PGO (PGO@P. denitrificans) stably by covalent coupling process after acclimatization and high-concentrated DMF (2000 mg/L) could be removed completely and relatively rapidly from aqueous solutions by the simultaneous adsorption-biodegradation (SAB) process of PGO@P. denitrificans. Furthermore, the excellent recycle performance of PGO@P. denitrificans made the whole process more economical and practical. PMID:26829653

  4. Industrial vitamin B12 production by Pseudomonas denitrificans using maltose syrup and corn steep liquor as the cost-effective fermentation substrates.

    PubMed

    Xia, Wei; Chen, Wei; Peng, Wei-Fu; Li, Kun-Tai

    2015-06-01

    The aerobic Pseudomonas denitrificans is widely used for industrial and commercial vitamin B12 fermentation, due to its higher productivity compared to the anaerobic vitamin B12-producing microorganisms. This paper aimed to develop a cost-effective fermentation medium for industrial vitamin B12 production by P. denitrificans in 120,000-l fermenter. It was found that maltose syrup (a low-cost syrup from corn starch by means of enzymatic or acid hydrolysis) and corn steep liquor (CSL, a by-product of starch industry) were greatly applicable to vitamin B12 production by P. denitrificans. Under the optimal fermentation medium performed by response surface methodology, 198.27 ± 4.60 mg/l of vitamin B12 yield was obtained in 120,000-l fermenter, which was close to the fermentation with the refined sucrose (198.80 mg/l) and was obviously higher than that obtained under beet molasses utilization (181.75 mg/l). Therefore, maltose syrups and CSL were the efficient and economical substrates for industrial vitamin B12 fermentation by P. denitrificans.

  5. Crystal structure of nitrous oxide reductase from Paracoccus denitrificans at 1.6 A resolution.

    PubMed Central

    Haltia, Tuomas; Brown, Kieron; Tegoni, Mariella; Cambillau, Christian; Saraste, Matti; Mattila, Kimmo; Djinovic-Carugo, Kristina

    2003-01-01

    N2O is generated by denitrifying bacteria as a product of NO reduction. In denitrification, N2O is metabolized further by the enzyme N2O reductase (N2OR), a multicopper protein which converts N2O into dinitrogen and water. The structure of N2OR remained unknown until the recent elucidation of the structure of the enzyme isolated from Pseudomonas nautica. In the present paper, we report the crystal structure of a blue form of the enzyme that was purified under aerobic conditions from Paracoccus denitrificans. N2OR is a head-to-tail homodimer stabilized by a multitude of interactions including two calcium sites located at the intermonomeric surface. Each monomer is composed of two domains: a C-terminal cupredoxin domain that carries the dinuclear electron entry site known as Cu(A), and an N-terminal seven-bladed beta-propeller domain which hosts the active-site centre Cu(Z). The electrons are transferred from Cu(A) to Cu(Z) across the subunit interface. Cu(Z) is a tetranuclear copper cluster in which the four copper ions (Cu1 to Cu4) are ligated by seven histidine imidazoles, a hydroxyl or water oxygen and a bridging inorganic sulphide. A bound chloride ion near the Cu(Z) active site shares one of the ligand imidazoles of Cu1. This arrangement probably influences the redox potential of Cu1 so that this copper is stabilized in the cupric state. The treatment of N2OR with H2O2 or cyanide causes the disappearance of the optical band at 640 nm, attributed to the Cu(Z) centre. The crystal structure of the enzyme soaked with H2O2 or cyanide suggests that an average of one copper of the Cu(Z) cluster has been lost. The lowest occupancy is observed for Cu3 and Cu4. A docking experiment suggests that N(2)O binds between Cu1 and Cu4 so that the oxygen of N2O replaces the oxygen ligand of Cu4. Certain ligand imidazoles of Cu1 and Cu2, as well as of Cu4, are located at the dimer interface. Particularly those of Cu2 and Cu4 are parts of a bonding network which couples these

  6. Genome-Enabled Studies of Anaerobic, Nitrate-Dependent Iron Oxidation in the Chemolithoautotrophic Bacterium Thiobacillus denitrificans

    NASA Astrophysics Data System (ADS)

    Beller, H. R.; Zhou, P.; Legler, T. C.; Chakicherla, A.; O'Day, P. A.

    2013-12-01

    Thiobacillus denitrificans is a chemolithoautotrophic bacterium capable of anaerobic, nitrate-dependent U(IV) and Fe(II) oxidation, both of which can strongly influence the long-term efficacy of in situ reductive immobilization of uranium in contaminated aquifers. We previously identified two c-type cytochromes involved in nitrate-dependent U(IV) oxidation in T. denitrificans and hypothesized that c-type cytochromes would also catalyze Fe(II) oxidation, as they have been found to play this role in anaerobic phototrophic Fe(II)-oxidizing bacteria. Here we report on efforts to identify genes associated with nitrate-dependent Fe(II) oxidation, namely (a) whole-genome transcriptional studies [using FeCO3, Fe2+, and U(IV) oxides as electron donors under denitrifying conditions], (b) Fe(II) oxidation assays performed with knockout mutants targeting primarily highly expressed or upregulated c-type cytochromes, and (c) random transposon-mutagenesis studies with screening for Fe(II) oxidation. Assays of mutants for 26 target genes, most of which were c-type cytochromes, indicated that none of the mutants tested were significantly defective in nitrate-dependent Fe(II) oxidation. The non-defective mutants included the c1-cytochrome subunit of the cytochrome bc1 complex (complex III), which has relevance to a previously proposed role for this complex in nitrate-dependent Fe(II) oxidation and to current concepts of reverse electron transfer. Of the transposon mutants defective in Fe(II) oxidation, one mutant with a disrupted gene associated with NADH:ubiquinone oxidoreductase (complex I) was ~35% defective relative to the wild-type strain; this strain was similarly defective in nitrate reduction with thiosulfate as the electron donor. Overall, our results indicate that nitrate-dependent Fe(II) oxidation in T. denitrificans is not catalyzed by the same c-type cytochromes involved in U(IV) oxidation, nor have other c-type cytochromes yet been implicated in the process.

  7. Secondary metabolites extracted from marine sponge associated Comamonas testosteroni and Citrobacter freundii as potential antimicrobials against MDR pathogens and hypothetical leads for VP40 matrix protein of Ebola virus: an in vitro and in silico investigation.

    PubMed

    Skariyachan, Sinosh; Acharya, Archana B; Subramaniyan, Saumya; Babu, Sumangala; Kulkarni, Shruthi; Narayanappa, Rajeswari

    2016-09-01

    The current study explores therapeutic potential of metabolites extracted from marine sponge (Cliona sp.)-associated bacteria against MDR pathogens and predicts the binding prospective of probable lead molecules against VP40 target of Ebola virus. The metabolite-producing bacteria were characterized by agar overlay assay and as per the protocols in Bergey's manual of determinative bacteriology. The antibacterial activities of extracted metabolites were tested against clinical pathogens by well-diffusion assay. The selected metabolite producers were characterized by 16S rDNA sequencing. Chemical screening and Fourier Transform Infrared (FTIR) analysis for selected compounds were performed. The probable lead molecules present in the metabolites were hypothesized based on proximate analysis, FTIR data, and literature survey. The drug-like properties and binding potential of lead molecules against VP40 target of Ebola virus were hypothesized by computational virtual screening and molecular docking. The current study demonstrated that clear zones around bacterial colonies in agar overlay assay. Antibiotic sensitivity profiling demonstrated that the clinical isolates were multi-drug resistant, however; most of them showed sensitivity to secondary metabolites (MIC-15 μl/well). The proximate and FTIR analysis suggested that probable metabolites belonged to alkaloids with O-H, C-H, C=O, and N-H groups. 16S rDNA characterization of selected metabolite producers demonstrated that 96% and 99% sequence identity to Comamonas testosteroni and Citrobacter freundii, respectively. The docking studies suggested that molecules such as Gymnastatin, Sorbicillactone, Marizomib, and Daryamide can designed as probable lead candidates against VP40 target of Ebola virus.

  8. Electrochemistry suggests proton access from the exit site to the binuclear center in Paracoccus denitrificans cytochrome c oxidase pathway variants.

    PubMed

    Meyer, Thomas; Melin, Frédéric; Richter, Oliver-M H; Ludwig, Bernd; Kannt, Aimo; Müller, Hanne; Michel, Hartmut; Hellwig, Petra

    2015-02-27

    Two different pathways through which protons access cytochrome c oxidase operate during oxygen reduction from the mitochondrial matrix, or the bacterial cytoplasm. Here, we use electrocatalytic current measurements to follow oxygen reduction coupled to proton uptake in cytochrome c oxidase isolated from Paracoccus denitrificans. Wild type enzyme and site-specific variants with defects in both proton uptake pathways (K354M, D124N and K354M/D124N) were immobilized on gold nanoparticles, and oxygen reduction was probed electrochemically in the presence of varying concentrations of Zn(2+) ions, which are known to inhibit both the entry and the exit proton pathways in the enzyme. Our data suggest that under these conditions substrate protons gain access to the oxygen reduction site via the exit pathway.

  9. Isolation of ubiquinol oxidase from Paracoccus denitrificans and resolution into cytochrome bc1 and cytochrome c-aa3 complexes.

    PubMed

    Berry, E A; Trumpower, B L

    1985-02-25

    An enzyme complex with ubiquinol-cytochrome c oxidoreductase, cytochrome c oxidase, and ubiquinol oxidase activities was purified from a detergent extract of the plasma membrane of aerobically grown Paracoccus denitrificans. This ubiquinol oxidase consists of seven polypeptides and contains two b cytochromes, cytochrome c1, cytochrome aa3, and a previously unreported c-type cytochrome. This c-type cytochrome has an apparent Mr of 22,000 and an alpha absorption maximum at 552 nm. Retention of this c cytochrome through purification presumably accounts for the independence of ubiquinol oxidase activity on added cytochrome c. Ubiquinol oxidase can be separated into a 3-subunit bc1 complex, a 3-subunit c-aa3 complex, and a 57-kDa polypeptide. This, together with detection of covalently bound heme and published molecular weights of cytochrome c1 and the subunits of cytochrome c oxidase, allows tentative identification of most of the subunits of ubiquinol oxidase with the prosthetic groups present. Ubiquinol oxidase contains cytochromes corresponding to those of the mitochondrial bc1 complex, cytochrome c oxidase complex, and a bound cytochrome c. Ubiquinol-cytochrome c oxidoreductase activity of the complex is inhibited by inhibitors of the mitochondrial bc1 complex. Thus it seems likely that the pathway of electron transfer through the bc1 complex of ubiquinol oxidase is similar to that through the mitochondrial bc1 complex. The number of polypeptides present is less than half the number in the corresponding mitochondrial complexes. This structural simplicity may make ubiquinol oxidase from P. denitrificans a useful system with which to study the mechanisms of electron transfer and energy transduction in the bc1 and cytochrome c oxidase sections of the respiratory chain.

  10. Genome-Wide Discovery of Putative sRNAs in Paracoccus denitrificans Expressed under Nitrous Oxide Emitting Conditions

    PubMed Central

    Gaimster, Hannah; Chalklen, Lisa; Alston, Mark; Munnoch, John T.; Richardson, David J.; Gates, Andrew J.; Rowley, Gary

    2016-01-01

    Nitrous oxide (N2O) is a stable, ozone depleting greenhouse gas. Emissions of N2O into the atmosphere continue to rise, primarily due to the use of nitrogen-containing fertilizers by soil denitrifying microbes. It is clear more effective mitigation strategies are required to reduce emissions. One way to help develop future mitigation strategies is to address the currently poor understanding of transcriptional regulation of the enzymes used to produce and consume N2O. With this ultimate aim in mind we performed RNA-seq on a model soil denitrifier, Paracoccus denitrificans, cultured anaerobically under high N2O and low N2O emitting conditions, and aerobically under zero N2O emitting conditions to identify small RNAs (sRNAs) with potential regulatory functions transcribed under these conditions. sRNAs are short (∼40–500 nucleotides) non-coding RNAs that regulate a wide range of activities in many bacteria. Hundred and sixty seven sRNAs were identified throughout the P. denitrificans genome which are either present in intergenic regions or located antisense to ORFs. Furthermore, many of these sRNAs are differentially expressed under high N2O and low N2O emitting conditions respectively, suggesting they may play a role in production or reduction of N2O. Expression of 16 of these sRNAs have been confirmed by RT-PCR. Ninety percent of the sRNAs are predicted to form secondary structures. Predicted targets include transporters and a number of transcriptional regulators. A number of sRNAs were conserved in other members of the α-proteobacteria. Better understanding of the sRNA factors which contribute to expression of the machinery required to reduce N2O will, in turn, help to inform strategies for mitigation of N2O emissions. PMID:27895629

  11. Structure of a catalytic dimer of the α- and β-subunits of the F-ATPase from Paracoccus denitrificans at 2.3 Å resolution

    SciTech Connect

    Morales-Ríos, Edgar; Montgomery, Martin G.; Leslie, Andrew G. W.; García-Trejo, José J.; Walker, John E.

    2015-09-23

    The structure of the αβ heterodimer of the F-ATPase from the α-proteobacterium P. denitrificans has been determined at 2.3 Å resolution. It corresponds to the ‘open’ or ‘empty’ catalytic interface found in other F-ATPases. The structures of F-ATPases have predominantly been determined from mitochondrial enzymes, and those of the enzymes in eubacteria have been less studied. Paracoccus denitrificans is a member of the α-proteobacteria and is related to the extinct protomitochondrion that became engulfed by the ancestor of eukaryotic cells. The P. denitrificans F-ATPase is an example of a eubacterial F-ATPase that can carry out ATP synthesis only, whereas many others can catalyse both the synthesis and the hydrolysis of ATP. Inhibition of the ATP hydrolytic activity of the P. denitrificans F-ATPase involves the ζ inhibitor protein, an α-helical protein that binds to the catalytic F{sub 1} domain of the enzyme. This domain is a complex of three α-subunits and three β-subunits, and one copy of each of the γ-, δ- and ∊-subunits. Attempts to crystallize the F{sub 1}–ζ inhibitor complex yielded crystals of a subcomplex of the catalytic domain containing the α- and β-subunits only. Its structure was determined to 2.3 Å resolution and consists of a heterodimer of one α-subunit and one β-subunit. It has no bound nucleotides, and it corresponds to the ‘open’ or ‘empty’ catalytic interface found in other F-ATPases. The main significance of this structure is that it aids in the determination of the structure of the intact membrane-bound F-ATPase, which has been crystallized.

  12. Structure of the two-domain hexameric APS kinase from Thiobacillus denitrificans: structural basis for the absence of ATP sulfurylase activity

    SciTech Connect

    Gay, Sean C.; Segel, Irwin H.; Fisher, Andrew J.

    2009-10-01

    APS kinase from Thiobacillus denitrificans contains an inactive N-terminal ATP sulfurylase domain. The structure presented unveils the first hexameric assembly for an APS kinase, and reveals that structural changes in the N-terminal domain disrupt the ATP sulfurylase active site thus prohibiting activity. The Tbd-0210 gene of the chemolithotrophic bacterium Thiobacillus denitrificans is annotated to encode a 60.5 kDa bifunctional enzyme with ATP sulfurylase and APS kinase activity. This putative bifunctional enzyme was cloned, expressed and structurally characterized. The 2.95 Å resolution X-ray crystal structure reported here revealed a hexameric assembly with D{sub 3} symmetry. Each subunit contains a large N-terminal sulfurylase-like domain and a C-terminal APS kinase domain reminiscent of the two-domain fungal ATP sulfurylases of Penicillium chrysogenum and Saccharomyces cerevisiae, which also exhibit a hexameric assembly. However, the T. denitrificans enzyme exhibits numerous structural and sequence differences in the N-terminal domain that render it inactive with respect to ATP sulfurylase activity. Surprisingly, the C-terminal domain does indeed display APS kinase activity, indicating that this gene product is a true APS kinase. Therefore, these results provide the first structural insights into a unique hexameric APS kinase that contains a nonfunctional ATP sulfurylase-like domain of unknown function.

  13. The Fe-type nitrile hydratase from Comamonas testosteroni Ni1 does not require an activator accessory protein for expression in Escherichia coli

    SciTech Connect

    Kuhn, Misty L.; Martinez, Salette; Gumataotao, Natalie; Bornscheuer, Uwe; Liu, Dali; Holz, Richard C.

    2012-10-10

    We report herein the functional expression of an Fe-type nitrile hydratase (NHase) without the co-expression of an activator protein or the Escherichia coli chaperone proteins GroES/EL. Soluble protein was obtained when the {alpha}- and {beta}-subunit genes of the Fe-type NHase Comamonas testosteroni Ni1 (CtNHase) were synthesized with optimized E. coli codon usage and co-expressed. As a control, the Fe-type NHase from Rhodococcus equi TG328-2 (ReNHase) was expressed with (ReNHase{sup +Act}) and without (ReNHase{sup -Act}) its activator protein, establishing that expression of a fully functional, metallated ReNHase enzyme requires the co-expression of its activator protein, similar to all other Fe-type NHase enzymes reported to date, whereas the CtNHase does not. The X-ray crystal structure of CtNHase was determined to 2.4 {angstrom} resolution revealing an {alpha}{beta} heterodimer, similar to other Fe-type NHase enzymes, except for two important differences. First, two His residues reside in the CtNHase active site that are not observed in other Fe-type NHase enzymes and second, the active site Fe(III) ion resides at the bottom of a wide solvent exposed channel. The solvent exposed active site, along with the two active site histidine residues, are hypothesized to play a role in iron incorporation in the absence of an activator protein.

  14. The Fe-type nitrile hydratase from Comamonas testosteroni Ni1 does not require an activator accessory protein for expression in Escherichia coli.

    PubMed

    Kuhn, Misty L; Martinez, Salette; Gumataotao, Natalie; Bornscheuer, Uwe; Liu, Dali; Holz, Richard C

    2012-08-03

    We report herein the functional expression of an Fe-type nitrile hydratase (NHase) without the co-expression of an activator protein or the Escherichia coli chaperone proteins GroES/EL. Soluble protein was obtained when the α- and β-subunit genes of the Fe-type NHase Comamonas testosteroni Ni1 (CtNHase) were synthesized with optimized E. coli codon usage and co-expressed. As a control, the Fe-type NHase from Rhodococcus equi TG328-2 (ReNHase) was expressed with (ReNHase(+Act)) and without (ReNHase(-Act)) its activator protein, establishing that expression of a fully functional, metallated ReNHase enzyme requires the co-expression of its activator protein, similar to all other Fe-type NHase enzymes reported to date, whereas the CtNHase does not. The X-ray crystal structure of CtNHase was determined to 2.4Å resolution revealing an αβ heterodimer, similar to other Fe-type NHase enzymes, except for two important differences. First, two His residues reside in the CtNHase active site that are not observed in other Fe-type NHase enzymes and second, the active site Fe(III) ion resides at the bottom of a wide solvent exposed channel. The solvent exposed active site, along with the two active site histidine residues, are hypothesized to play a role in iron incorporation in the absence of an activator protein.

  15. Ligand specificity of MobR, a transcriptional regulator for the 3-hydroxybenzoate hydroxylase gene of Comamonas testosteroni KH122-3s

    SciTech Connect

    Yoshida, Mariko; Hiromoto, Takeshi; Hosokawa, Keiichi; Yamaguchi, Hiroshi; Fujiwara, Shinsuke

    2007-10-19

    MobR from Comamonas testosteroni KH122-3s is a member of the MarR family of transcriptional regulators and functions as a repressor for the mobA gene that encodes a 3-hydroxybenzoate 4-hydroxylase. 3-Hydroxybenzoate binds to MobR as a ligand, resulting in an efficient induction of mobA. Various 3-hydroxybenzoate analogues were examined for their inducibilities using the mobA::lacZ transcriptional fusion system. {beta}-Galactosidase was induced by the addition of 2,3-dihydroxybenzoate or 3,5-dihydroxybenzoate besides 3-hydroxybenzoate, suggesting that the hydroxyl group at position 3 is critical in addition to the carboxyl group on the aromatic ring. A gel mobility-shift assay also showed that MobR was released from the target DNA in the presence of these compounds. Circular dichroism studies demonstrated that MobR adopted two conformational states corresponding to the 3-hydroxybenzoate-bound and unbound forms. Other ligands also induced the structural change as well; however, the tertiary structures of converted forms were different from those by 3-hydroxybenzoate.

  16. Map of the IncP1β Plasmid pTSA Encoding the Widespread Genes (tsa) for p-Toluenesulfonate Degradation in Comamonas testosteroni T-2

    PubMed Central

    Tralau, Tewes; Cook, Alasdair M.; Ruff, Juergen

    2001-01-01

    The catabolic IncP1β plasmid pTSA from Comamonas testosteroni T-2 was mapped by subtractive analysis of restriction digests, by sequencing outwards from the tsa operon (toluenesulfonate degradation), and by generating overlapping, long-distance-PCR amplification products. The plasmid was estimated to comprise 72 ± 4 kb. The tsa region was found to be a composite transposon flanked by two IS1071 elements. A cryptic tsa operon was also present in the tsa transposon. Those backbone genes and regions which we sequenced were in the same order as the corresponding genes in resistance plasmid R751, and identities of about 99% were observed. Enrichment cultures with samples from four continents were done to obtain organisms able to utilize p-toluenesulfonate as the sole source of carbon and energy for aerobic growth. Most (15) of the 16 cultures (13 of them isolates) were obtained from contaminated sites and were attributed to three metabolic groups, depending on their metabolism of p-toluenesulfonate. The largest group contained the tsa transposon, usually (six of seven isolates) with negligible differences in sequence from strain T-2. PMID:11282598

  17. Transcriptional regulation, metal binding properties and structure of Pden1597, an unusual zinc transport protein from Paracoccus denitrificans

    DOE PAGES

    Handali, Melody; Neupane, Durga P.; Roychowdhury, Hridindu; ...

    2015-03-18

    Here, ATP-binding cassette (ABC) transporters of the cluster 9 family are ubiquitous among bacteria and essential for acquiring Zn2+ and Mn2+ from the environment or, in the case of pathogens, from the host. These rely on a substrate-binding protein (SBP) to coordinate the relevant metal with high affinity and specificity and subsequently release it to a membrane permease for translocation into the cytoplasm. Although a number of cluster 9 SBP structures have been determined, the structural attributes conferring Zn2+ or Mn2+ specificity remain ambiguous. Here we describe the gene expression profile, in vitro metal binding properties, and crystal structure ofmore » a new cluster 9 SBP from Paracoccus denitrificans we have called AztC. Although all of our results strongly indicate Zn2+ over Mn2+ specificity, the Zn2+ ion is coordinated by a conserved Asp residue only observed to date as a metal ligand in Mn2+-specific SBPs. The unusual sequence properties of this protein are shared among close homologues, including members from the human pathogens Klebsiella pneumonia and Enterobacter aerogenes, and would seem to suggest a subclass of Zn2+-specific transporters among the cluster 9 family. In any case, the unusual coordination environment of AztC expands the already considerable range of those available to Zn2+-specific SBPs and highlights the presence of a His-rich loop as the most reliable indicator of Zn2+ specificity.« less

  18. Kinetics of the interaction of the cytochrome c oxidase of Paracoccus denitrificans with its own and bovine cytochrome c.

    PubMed

    Bolgiano, B; Smith, L; Davies, H C

    1988-04-22

    We have devised a relatively simple method for the purification of cytochrome aa3 of Paracoccus denitrificans with three major subunits similar to those of the larger subunits of the mitochondrial cytochrome oxidase. This preparation has no c-type cytochrome. Studies were made of the oxidation of soluble cytochromes c from bovine heart and Paracoccus. The cytochrome-c oxidase activity was stimulated by low concentrations of either cytochrome c, providing an explanation for the multiphasic nature of plots of v/S versus v. Kinetics of the oxidation of bovine cytochrome c by the Paracoccus oxidase resembled those of bovine oxidase with bovine cytochrome c in every way; the Paracoccus oxidase with bovine cytochrome c can serve as an appropriate model for the mitochondrial system. The kinetics of the oxidation of the soluble Paracoccus cytochrome c by the Paracoccus oxidase were different from those seen with bovine cytochrome c, but resembled the latter if poly(L-lysine) was added to the assays. The important difference between the two species of cytochrome c is the more highly negative hemisphere on the side of the molecule way from the heme crevice in the Paracoccus cytochrome. Thus, the data emphasize the importance of all of the charged groups on cytochrome c in influencing the binding or electron transfer reactions of this oxidation-reduction system. The data also permit some interesting connotations about the possible evolution from the bacterial to the mitochondrial electron transport system.

  19. Achromobacter denitrificans Strain YD35 Pyruvate Dehydrogenase Controls NADH Production To Allow Tolerance to Extremely High Nitrite Levels

    PubMed Central

    Doi, Yuki; Shimizu, Motoyuki; Fujita, Tomoya; Nakamura, Akira; Takizawa, Noboru

    2014-01-01

    We identified the extremely nitrite-tolerant bacterium Achromobacter denitrificans YD35 that can grow in complex medium containing 100 mM nitrite (NO2−) under aerobic conditions. Nitrite induced global proteomic changes and upregulated tricarboxylate (TCA) cycle enzymes as well as antioxidant proteins in YD35. Transposon mutagenesis generated NO2−-hypersensitive mutants of YD35 that had mutations at genes for aconitate hydratase and α-ketoglutarate dehydrogenase in the TCA cycle and a pyruvate dehydrogenase (Pdh) E1 component, indicating the importance of TCA cycle metabolism to NO2− tolerance. A mutant in which the pdh gene cluster was disrupted (Δpdh mutant) could not grow in the presence of 100 mM NO2−. Nitrite decreased the cellular NADH/NAD+ ratio and the cellular ATP level. These defects were more severe in the Δpdh mutant, indicating that Pdh contributes to upregulating cellular NADH and ATP and NO2−-tolerant growth. Exogenous acetate, which generates acetyl coenzyme A and then is metabolized by the TCA cycle, compensated for these defects caused by disruption of the pdh gene cluster and those caused by NO2−. These findings demonstrate a link between NO2− tolerance and pyruvate/acetate metabolism through the TCA cycle. The TCA cycle mechanism in YD35 enhances NADH production, and we consider that this contributes to a novel NO2−-tolerating mechanism in this strain. PMID:24413603

  20. Biosynthesis of poly-3-hydroxybutyrate (PHB) from glycerol by Paracoccus denitrificans in a batch bioreactor: effect of process variables.

    PubMed

    Kalaiyezhini, D; Ramachandran, K B

    2015-01-01

    In this study, the kinetics of poly-3-hydroxybutyrate (PHB) biosynthesis from glycerol by Paracoccus denitrificans DSMZ 413 were explored in a batch bioreactor. Effects of inorganic and organic nitrogen source, carbon to nitrogen ratio, and other process variables such as pH, aeration, and initial glycerol concentration on PHB production were investigated in a 2.5-L bioreactor. Yeast extract was found to be the best nitrogen source compared to several organic nitrogen sources tested. At pH 6, specific growth rate, product formation rate, and accumulation of PHB within the cell were maximum. Specific growth rate increased with increase in oxygen transfer rate, but moderate oxygen transfer rate promoted PHB production. High glycerol concentration inhibited specific product formation rate but not growth. High initial carbon/nitrogen (C/N) ratio favored PHB accumulation and its productivity. At a C/N ratio of 21.4 (mol mol(-1)), 10.7 g L(-1) of PHB corresponding to 72% of cell dry weight was attained.

  1. Two enzymes of a complete degradation pathway for linear alkylbenzenesulfonate (LAS) surfactants: 4-sulfoacetophenone Baeyer-Villiger monooxygenase and 4-sulfophenylacetate esterase in Comamonas testosteroni KF-1.

    PubMed

    Weiss, Michael; Denger, Karin; Huhn, Thomas; Schleheck, David

    2012-12-01

    Complete biodegradation of the surfactant linear alkylbenzenesulfonate (LAS) is accomplished by complex bacterial communities in two steps. First, all LAS congeners are degraded into about 50 sulfophenylcarboxylates (SPC), one of which is 3-(4-sulfophenyl)butyrate (3-C(4)-SPC). Second, these SPCs are mineralized. 3-C(4)-SPC is mineralized by Comamonas testosteroni KF-1 in a process involving 4-sulfoacetophenone (SAP) as a metabolite and an unknown inducible Baeyer-Villiger monooxygenase (BVMO) to yield 4-sulfophenyl acetate (SPAc) from SAP (SAPMO enzyme); hydrolysis of SPAc to 4-sulfophenol and acetate is catalyzed by an unknown inducible esterase (SPAc esterase). Transcriptional analysis showed that one of four candidate genes for BVMOs in the genome of strain KF-1, as well as an SPAc esterase candidate gene directly upstream, was inducibly transcribed during growth with 3-C(4)-SPC. The same genes were identified by enzyme purification and peptide fingerprinting-mass spectrometry when SAPMO was enriched and SPAc esterase purified to homogeneity by protein chromatography. Heterologously overproduced pure SAPMO converted SAP to SPAc and was active with phenylacetone and 4-hydroxyacetophenone but not with cyclohexanone and progesterone. SAPMO showed the highest sequence homology to the archetypal phenylacetone BVMO (57%), followed by steroid BVMO (55%) and 4-hydroxyacetophenone BVMO (30%). Finally, the two pure enzymes added sequentially, SAPMO with NADPH and SAP, and then SPAc esterase, catalyzed the conversion of SAP via SPAc to 4-sulfophenol and acetate in a 1:1:1:1 molar ratio. Hence, the first two enzymes of a complete LAS degradation pathway were identified, giving evidence for the recruitment of members of the very versatile type I BVMO and carboxylester hydrolase enzyme families for the utilization of a xenobiotic compound by bacteria.

  2. Two Enzymes of a Complete Degradation Pathway for Linear Alkylbenzenesulfonate (LAS) Surfactants: 4-Sulfoacetophenone Baeyer-Villiger Monooxygenase and 4-Sulfophenylacetate Esterase in Comamonas testosteroni KF-1

    PubMed Central

    Weiss, Michael; Denger, Karin; Huhn, Thomas

    2012-01-01

    Complete biodegradation of the surfactant linear alkylbenzenesulfonate (LAS) is accomplished by complex bacterial communities in two steps. First, all LAS congeners are degraded into about 50 sulfophenylcarboxylates (SPC), one of which is 3-(4-sulfophenyl)butyrate (3-C4-SPC). Second, these SPCs are mineralized. 3-C4-SPC is mineralized by Comamonas testosteroni KF-1 in a process involving 4-sulfoacetophenone (SAP) as a metabolite and an unknown inducible Baeyer-Villiger monooxygenase (BVMO) to yield 4-sulfophenyl acetate (SPAc) from SAP (SAPMO enzyme); hydrolysis of SPAc to 4-sulfophenol and acetate is catalyzed by an unknown inducible esterase (SPAc esterase). Transcriptional analysis showed that one of four candidate genes for BVMOs in the genome of strain KF-1, as well as an SPAc esterase candidate gene directly upstream, was inducibly transcribed during growth with 3-C4-SPC. The same genes were identified by enzyme purification and peptide fingerprinting-mass spectrometry when SAPMO was enriched and SPAc esterase purified to homogeneity by protein chromatography. Heterologously overproduced pure SAPMO converted SAP to SPAc and was active with phenylacetone and 4-hydroxyacetophenone but not with cyclohexanone and progesterone. SAPMO showed the highest sequence homology to the archetypal phenylacetone BVMO (57%), followed by steroid BVMO (55%) and 4-hydroxyacetophenone BVMO (30%). Finally, the two pure enzymes added sequentially, SAPMO with NADPH and SAP, and then SPAc esterase, catalyzed the conversion of SAP via SPAc to 4-sulfophenol and acetate in a 1:1:1:1 molar ratio. Hence, the first two enzymes of a complete LAS degradation pathway were identified, giving evidence for the recruitment of members of the very versatile type I BVMO and carboxylester hydrolase enzyme families for the utilization of a xenobiotic compound by bacteria. PMID:23001656

  3. 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.

  4. Isolation and characterization of Alicycliphilus denitrificans strain BC, which grows on benzene with chlorate as the electron acceptor.

    PubMed

    Weelink, Sander A B; Tan, Nico C G; ten Broeke, Harm; van den Kieboom, Corné; van Doesburg, Wim; Langenhoff, Alette A M; Gerritse, Jan; Junca, Howard; Stams, Alfons J M

    2008-11-01

    A bacterium, strain BC, was isolated from a benzene-degrading chlorate-reducing enrichment culture. Strain BC degrades benzene in conjunction with chlorate reduction. Cells of strain BC are short rods that are 0.6 microm wide and 1 to 2 microm long, are motile, and stain gram negative. Strain BC grows on benzene and some other aromatic compounds with oxygen or in the absence of oxygen with chlorate as the electron acceptor. Strain BC is a denitrifying bacterium, but it is not able to grow on benzene with nitrate. The closest cultured relative is Alicycliphilus denitrificans type strain K601, a cyclohexanol-degrading nitrate-reducing betaproteobacterium. Chlorate reductase (0.4 U/mg protein) and chlorite dismutase (5.7 U/mg protein) activities in cell extracts of strain BC were determined. Gene sequences encoding a known chlorite dismutase (cld) were not detected in strain BC by using the PCR primers described in previous studies. As physiological and biochemical data indicated that there was oxygenation of benzene during growth with chlorate, a strategy was developed to detect genes encoding monooxygenase and dioxygenase enzymes potentially involved in benzene degradation in strain BC. Using primer sets designed to amplify members of distinct evolutionary branches in the catabolic families involved in benzene biodegradation, two oxygenase genes putatively encoding the enzymes performing the initial successive monooxygenations (BC-BMOa) and the cleavage of catechol (BC-C23O) were detected. Our findings suggest that oxygen formed by dismutation of chlorite can be used to attack organic molecules by means of oxygenases, as exemplified with benzene. Thus, aerobic pathways can be employed under conditions in which no external oxygen is supplied.

  5. Whole-Genome Transcriptional Analysis of Chemolithoautotrophic Thiosulfate Oxidation by Thiobacillus denitrificans Under Aerobic vs. Denitrifying Conditions

    SciTech Connect

    Beller, H R; Letain, T E; Chakicherla, A; Kane, S R; Legler, T C; Coleman, M A

    2006-04-22

    Thiobacillus denitrificans is one of the few known obligate chemolithoautotrophic bacteria capable of energetically coupling thiosulfate oxidation to denitrification as well as aerobic respiration. As very little is known about the differential expression of genes associated with ke chemolithoautotrophic functions (such as sulfur-compound oxidation and CO2 fixation) under aerobic versus denitrifying conditions, we conducted whole-genome, cDNA microarray studies to explore this topic systematically. The microarrays identified 277 genes (approximately ten percent of the genome) as differentially expressed using Robust Multi-array Average statistical analysis and a 2-fold cutoff. Genes upregulated (ca. 6- to 150-fold) under aerobic conditions included a cluster of genes associated with iron acquisition (e.g., siderophore-related genes), a cluster of cytochrome cbb3 oxidase genes, cbbL and cbbS (encoding the large and small subunits of form I ribulose 1,5-bisphosphate carboxylase/oxygenase, or RubisCO), and multiple molecular chaperone genes. Genes upregulated (ca. 4- to 95-fold) under denitrifying conditions included nar, nir, and nor genes (associated respectively with nitrate reductase, nitrite reductase, and nitric oxide reductase, which catalyze successive steps of denitrification), cbbM (encoding form II RubisCO), and genes involved with sulfur-compound oxidation (including two physically separated but highly similar copies of sulfide:quinone oxidoreductase and of dsrC, associated with dissimilatory sulfite reductase). Among genes associated with denitrification, relative expression levels (i.e., degree of upregulation with nitrate) tended to decrease in the order nar > nir > nor > nos. Reverse transcription, quantitative PCR analysis was used to validate these trends.

  6. Structure of ATP synthase from Paracoccus denitrificans determined by X-ray crystallography at 4.0 Å resolution

    PubMed Central

    Morales-Rios, Edgar; Montgomery, Martin G.; Leslie, Andrew G. W.; Walker, John E.

    2015-01-01

    The structure of the intact ATP synthase from the α-proteobacterium Paracoccus denitrificans, inhibited by its natural regulatory ζ-protein, has been solved by X-ray crystallography at 4.0 Å resolution. The ζ-protein is bound via its N-terminal α-helix in a catalytic interface in the F1 domain. The bacterial F1 domain is attached to the membrane domain by peripheral and central stalks. The δ-subunit component of the peripheral stalk binds to the N-terminal regions of two α-subunits. The stalk extends via two parallel long α-helices, one in each of the related b and b′ subunits, down a noncatalytic interface of the F1 domain and interacts in an unspecified way with the a-subunit in the membrane domain. The a-subunit lies close to a ring of 12 c-subunits attached to the central stalk in the F1 domain, and, together, the central stalk and c-ring form the enzyme’s rotor. Rotation is driven by the transmembrane proton-motive force, by a mechanism where protons pass through the interface between the a-subunit and c-ring via two half-channels in the a-subunit. These half-channels are probably located in a bundle of four α-helices in the a-subunit that are tilted at ∼30° to the plane of the membrane. Conserved polar residues in the two α-helices closest to the c-ring probably line the proton inlet path to an essential carboxyl group in the c-subunit in the proton uptake site and a proton exit path from the proton release site. The structure has provided deep insights into the workings of this extraordinary molecular machine. PMID:26460036

  7. Complete genomes of freshwater sulfur oxidizers Sulfuricella denitrificans skB26 and Sulfuritalea hydrogenivorans sk43H: genetic insights into the sulfur oxidation pathway of betaproteobacteria.

    PubMed

    Watanabe, Tomohiro; Kojima, Hisaya; Fukui, Manabu

    2014-09-01

    Despite detailed studies of marine sulfur-oxidizing bacteria, our knowledge concerning their counterparts in freshwater lake ecosystems is limited. Genome sequencing of the freshwater sulfur-oxidizing betaproteobacteria Sulfuricella denitrificans skB26 and Sulfuritalea hydrogenivorans sk43H have been completed. Strain skB26 possessed a circular plasmid of 86.6-kbp in addition to its chromosome, and an approximate 18-kbp region of the plasmid was occupied by an arxA-like operon, encoding a new clade of anaerobic arsenite oxidase. Multilocus sequence analysis showed that strain skB26 could not be assigned to any existing order; thus a novel order, Sulfuricellales, is proposed. The genomes of strains skB26 and sk43H were examined, focusing on the composition and the phylogeny of genes involved in the oxidation of inorganic sulfur compounds. Strains skB26 and sk43H shared a common pathway, which consisted of Sqr, SoxEF, SoxXYZAB, Dsr proteins, AprBA, Sat, and SoeABC. Comparative genomics of betaproteobacterial sulfur oxidizers showed that this pathway was also shared by the freshwater sulfur oxidizers Thiobacillus denitrificans and Sideroxydans lithotrophicus. It also revealed the presence of a conserved gene cluster, which was located immediately upstream of the betaproteobacterial dsr operon.

  8. Structural and functional analysis of aa3-type and cbb3-type cytochrome c oxidases of Paracoccus denitrificans reveals significant differences in proton-pump design.

    PubMed

    de Gier, J W; Schepper, M; Reijnders, W N; van Dyck, S J; Slotboom, D J; Warne, A; Saraste, M; Krab, K; Finel, M; Stouthamer, A H; van Spanning, R J; van der Oost, J

    1996-06-01

    In Paracoccus denitrificans the aa3-type cytochrome c oxidase and the bb3-type quinol oxidase have previously been characterized in detail, both biochemically and genetically. Here we report on the isolation of a genomic locus that harbours the gene cluster ccoNOOP, and demonstrate that it encodes an alternative cbb3-type cytochrome c oxidase. This oxidase has previously been shown to be specifically induced at low oxygen tensions, suggesting that its expression is controlled by an oxygen-sensing mechanism. This view is corroborated by the observation that the ccoNOOP gene cluster is preceded by a gene that encodes an FNR homologue and that its promoter region contains an FNR-binding motif. Biochemical and physiological analyses of a set of oxidase mutants revealed that, at least under the conditions tested, cytochromes aa3, bb3 and cbb3 make up the complete set of terminal oxidases in P. denitrificans. Proton-translocation measurements of these oxidase mutants indicate that all three oxidase types have the capacity to pump protons. Previously, however, we have reported decreased H+/e- coupling efficiencies of the cbb3-type oxidase under certain conditions. Sequence alignment suggests that many residues that have been proposed to constitute the chemical and pumped proton channels in cytochrome aa3 (and probably also in cytochrome bb3) are not conserved in cytochrome cbb3. It is concluded that the design of the proton pump in cytochrome cbb3 differs significantly from that in the other oxidase types.

  9. Modification of surface and enzymatic properties of Achromobacter denitrificans and Stenotrophomonas maltophilia in association with diesel oil biodegradation enhanced with alkyl polyglucosides.

    PubMed

    Sałek, Karina; Zgoła-Grześkowiak, Agnieszka; Kaczorek, Ewa

    2013-11-01

    The article concerns the influence of selected alkyl polyglucosides on biodegradation, cell surface and enzymatic properties of Stenotrophomonas maltophilia and Achromobacter denitrificans. The biodegradation of diesel oil depends on several factors including type and the amount of surfactant as well as bacterial genera used in the process. Nevertheless, a careful selection of these variables must be made as some bacterial strains prefer to use surfactants as their carbon source. This leads to the lowered biodegradation of diesel oil as can be observed for the tested S. maltophilia strain. Alkyl polyglucosides influenced the cell surface properties of both of the tested strains in slightly different ways. Especially for A. denitrificans, for which the hydrophobicity increased with concentration of both--Lutensol GD 70 and Glucopon 215 in diesel oil-surfactant systems. Moreover, judging by the efficiency of biodegradation, the most effective process was observed in the presence of Lutensol GD 70 (240 and 360 mg L(-1)) with biodegradation rising from 32% (without surfactant) to 68%. No such relation was observed for S. maltophilia.

  10. The P aracoccus denitrificans NarK‐like nitrate and nitrite transporters—probing nitrate uptake and nitrate/nitrite exchange mechanisms

    PubMed Central

    Goddard, Alan D.; Bali, Shilpa; Mavridou, Despoina A.I.; Luque‐Almagro, Victor M.; Gates, Andrew J.; Dolores Roldán, M.; Newstead, Simon; Richardson, David J.

    2016-01-01

    Summary Nitrate and nitrite transport across biological membranes is often facilitated by protein transporters that are members of the major facilitator superfamily. Paracoccus denitrificans contains an unusual arrangement whereby two of these transporters, NarK1 and NarK2, are fused into a single protein, NarK, which delivers nitrate to the respiratory nitrate reductase and transfers the product, nitrite, to the periplasm. Our complementation studies, using a mutant lacking the nitrate/proton symporter NasA from the assimilatory nitrate reductase pathway, support that NarK1 functions as a nitrate/proton symporter while NarK2 is a nitrate/nitrite antiporter. Through the same experimental system, we find that Escherichia coli NarK and NarU can complement deletions in both narK and nasA in P. denitrificans, suggesting that, while these proteins are most likely nitrate/nitrite antiporters, they can also act in the net uptake of nitrate. Finally, we argue that primary sequence analysis and structural modelling do not readily explain why NasA, NarK1 and NarK2, as well as other transporters from this protein family, have such different functions, ranging from net nitrate uptake to nitrate/nitrite exchange. PMID:27696579

  11. Expression of the Nitroarene Dioxygenase Genes in Comamonas sp. Strain JS765 and Acidovorax sp. Strain JS42 Is Induced by Multiple Aromatic Compounds

    PubMed Central

    Lessner, Daniel J.; Parales, Rebecca E.; Narayan, Shakti; Gibson, David T.

    2003-01-01

    This work reports a genetic analysis of the expression of nitrobenzene dioxygenase (NBDO) in Comamonas sp. strain JS765 and 2-nitrotoluene dioxygenase (2NTDO) in Acidovorax sp. strain JS42. Strains JS765 and JS42 possess identical LysR-type regulatory proteins, NbzR and NtdR, respectively. NbzR/NtdR is homologous to NahR, the positive salicylate-responsive transcriptional activator of the naphthalene degradation genes in Pseudomonas putida G7. The genes encoding NBDO and 2NTDO in each strain are cotranscribed, and transcription starts at the same site within identical promoter regions for each operon. Results from a lacZ reporter gene fusion demonstrated that expression of NBDO and 2NTDO is induced by multiple aromatic compounds, including an array of nitroaromatic compounds (nitrobenzene, 2-, 3-, and 4-nitrotoluene, 2,4- and 2,6-dinitrotoluene, and aminodinitrotoluenes), as well as salicylate and anthranilate. The nitroaromatic compounds appear to be the actual effector molecules. Analysis of β-galactosidase and 2NTDO activities with strain JS42 demonstrated that NtdR was required for induction by all of the inducing compounds, high basal-level expression of 2NTDO, and complementation of a JS42 ntdR null mutant. Complementation with the closely related regulators NagR (from Ralstonia sp. strain U2) and NahR restored only induction by the archetype inducers, salicylate or salicylate and anthranilate, respectively, and did not restore the high basal level of expression of 2NTDO. The mechanism of 2NTDO gene regulation in JS42, and presumably that of NBDO gene regulation in JS765, appear similar to that of NahR-regulated genes in Pseudomonas putida G7. However, NbzR and NtdR appear to have evolved a broader specificity in JS42 and JS765, allowing for recognition of nitroaromatic compounds while retaining the ability to respond to salicylate and anthranilate. NtdR is also the first example of a nitroarene-responsive LysR-type transcriptional activator. PMID:12813084

  12. Isolation and identification of a repressor TetR for 3,17β-HSD expressional regulation in Comamonas testosteroni.

    PubMed

    Pan, Tianyuan; Huang, Pu; Xiong, Guangming; Maser, Edmund

    2015-06-05

    Comamonas testosteroni (C. testosteroni) is able to catabolize a variety of steroids and polycyclic aromatic hydrocarbons. 3,17β-Hydroxysteroid dehydrogenase (3,17β-HSD) from C. testosteroni is a key enzyme in steroid degradation. Understanding the mechanism of 3,17β-HSD gene (βhsd) induction may help us to elucidate its complete molecular regulation. Sequencing the C. testosteroni ATCC11996 genome lead us to identify the tetR (522 bp) downstream of βhsd. Two repeat sequences (RS; 13 bp), that are separated to each other by 1661 bp, were found upstream of βhsd. A bioinformatic analysis revealed that TetR family proteins act as transcriptional repressors which are sensitive to environmental signals. Since, C. testosteroni responds to environmental steroid induction and upregulates steroid catabolic genes, we hypothesized that TetR might act in C. testosteroni as repressor for βhsd expression. The tetR was cloned into different plasmids, including an EGFP reporter system, for functional characterization and/or overexpression. The data indicate that, indeed, TetR acts as a repressor for 3,17β-HSD expression. Testosterone in turn, which is known to induce βhsd expression, could not resolve TetR repression. To further substantiate TetR as repressor for βhsd expression, a tetR gene knock-out mutant of C. testosteroni was generated. TetR gene knock-out mutants showed the same basal low level of βhsd expression as the C. testosteroni wild type cells. Interestingly, testosterone induction leads to a strong increase in βhsd expression, especially in the tetR gene knock-out mutants. The result with the knock-out mutant, in principle, supports our hypothesis that TetR is a repressor for βhsd expression, but the exact role of testosterone in this context remains unknown. Finally, it turned out that TetR is obviously also involved in the regulation of the hsdA gene.

  13. Structure of the puf operon of the obligately aerobic, bacteriochlorophyll alpha-containing bacterium Roseobacter denitrificans OCh114 and its expression in a Rhodobacter capsulatus puf puc deletion mutant.

    PubMed Central

    Kortlüke, C; Breese, K; Gad'on, N; Labahn, A; Drews, G

    1997-01-01

    Roseobacter denitrificans (Erythrobacter species strain OCh114) synthesizes bacteriochlorophyll a (BChl) and the photosynthetic apparatus only in the presence of oxygen and is unable to carry out primary photosynthetic reactions and to grow photosynthetically under anoxic conditions. The puf operon of R. denitrificans has the same five genes in the same order as in many photosynthetic bacteria, i.e., pufBALMC. PufC, the tetraheme subunit of the reaction center (RC), consists of 352 amino acids (Mr, 39,043); 20 and 34% of the total amino acids are identical to those of PufC of Chloroflexus aurantiacus and Rubrivivax gelatinosus, respectively. The N-terminal hydrophobic domain is probably responsible for anchoring the subunit in the membrane. Four heme-binding domains are homologous to those of PufC in several purple bacteria. Sequences similar to pufQ and pufX of Rhodobacter capsulatus were not detected on the chromosome of R. denitrificans. The puf operon of R. denitrificans was expressed in trans in Escherichia coli, and all gene products were synthesized. The Roseobacter puf operon was also expressed in R. capsulatus CK11, a puf puc double-deletion mutant. For the first time, an RC/light-harvesting complex I core complex was heterologously synthesized. The strongest expression of the R. denitrificans puf operon was observed under the control of the R. capsulatus puf promoter, in the presence of pufQ and pufX and in the absence of pufC. Charge recombination between the primary donor P+ and the primary ubiquinone Q(A)- was observed in the transconjugant, showing that the M and L subunits of the RC were correctly assembled. The transconjugants did not grow photosynthetically under anoxic conditions. PMID:9286973

  14. Uptake of benzoic acid and chloro-substituted benzoic acids by alcaligenes denitrificans BRI 3010 and BRI 6011

    SciTech Connect

    Miguez, C.B.; Ingram, J.M.; MacLeod, R.A.

    1995-12-01

    The mechanism of uptake of benzoic and 2,4-dichlorobenzoic acid (2,4-DCBA) by Alcaligenes denitrificans BRI 3010 and BRI 6011 and Pseudomonas sp. strain B13, three organisms capable of degrading isomers of chlorinated benzoic acids, was investigated. In all three organisms, uptake of benzoic acid was inducible. For benzoic acid uptake into BRI 3010, monophasic saturation kinetics with apparent K{sub m} and V{sub max} values of 1.4 {mu}M and 3.2 nmol/min/mg of cell dry weight, respectively, were obtained. For BRI 6011, biphasic saturation kinetics were observed, suggesting presence of two uptake systems for benzoic acid with distinct K{sub m} (0.72 and 5.3 {mu}M) and V{sub max} (3.3 and 4.6 nmol/min/mg of cell dry weight) values. BRI 3010 and BRI 6011 accumulated benzoic acid against a concentration gradient by a factor of 8 and 10, respectively. A wide range of structural analogs, at 50-fold excess concentrations, inhibited benzoic acid uptake by BRI 3010 and BRI 6011, whereas with B13, only 3-chlorobenzoic acid was an effective inhibitor. For BRI 3010 and BRI 6011, the inhibition by the structural analogs was not of a competitive nature. Uptake of benzoic acid by BRI 3010 and BRI 6011 was inhibited by KCN, by the protonophore 3,5,3`, 4`-tetrachlorosalicylanilide (TCS), and, for BRI 6011, by anaerobiosis unless nitrate was present, thus indicating that energy was required for the uptake process. Uptake of 2,4-DCBA by BRI 6011 was constitutive and saturation uptake kinetics were not observed. Uptake of 2,4-DCBA by BRI 6011 was inhibited by KCN, TCS, and anaerobiosis even if nitrate was present, but the compound was not accumulated intracellularly against a concentration gradient. Uptake of 2,4-DCBA by BRI 6011 appears to occur by passive diffusion into the cell down its concentration gradient, which is maintained by the intracellular metabolism of the compound. This process could play an important role in the degradation of xenobiotic compounds by microorganisms.

  15. Tryptophan tryptophylquinone cofactor biogenesis in the aromatic amine dehydrogenase of Alcaligenes faecalis. Cofactor assembly and catalytic properties of recombinant enzyme expressed in Paracoccus denitrificans.

    PubMed

    Hothi, Parvinder; Khadra, Khalid Abu; Combe, Jonathan P; Leys, David; Scrutton, Nigel S

    2005-11-01

    The heterologous expression of tryptophan trytophylquinone (TTQ)-dependent aromatic amine dehydrogenase (AADH) has been achieved in Paracoccus denitrificans. The aauBEDA genes and orf-2 from the aromatic amine utilization (aau) gene cluster of Alcaligenes faecalis were placed under the regulatory control of the mauF promoter from P. denitrificans and introduced into P. denitrificans using a broad-host-range vector. The physical, spectroscopic and kinetic properties of the recombinant AADH were indistinguishable from those of the native enzyme isolated from A. faecalis. TTQ biogenesis in recombinant AADH is functional despite the lack of analogues in the cloned aau gene cluster for mauF, mauG, mauL, mauM and mauN that are found in the methylamine utilization (mau) gene cluster of a number of methylotrophic organisms. Steady-state reaction profiles for recombinant AADH as a function of substrate concentration differed between 'fast' (tryptamine) and 'slow' (benzylamine) substrates, owing to a lack of inhibition by benzylamine at high substrate concentrations. A deflated and temperature-dependent kinetic isotope effect indicated that C-H/C-D bond breakage is only partially rate-limiting in steady-state reactions with benzylamine. Stopped-flow studies of the reductive half-reaction of recombinant AADH with benzylamine demonstrated that the KIE is elevated over the value observed in steady-state turnover and is independent of temperature, consistent with (a) previously reported studies with native AADH and (b) breakage of the substrate C-H bond by quantum mechanical tunnelling. The limiting rate constant (k(lim)) for TTQ reduction is controlled by a single ionization with pK(a) value of 6.0, with maximum activity realized in the alkaline region. Two kinetically influential ionizations were identified in plots of k(lim)/K(d) of pK(a) values 7.1 and 9.3, again with the maximum value realized in the alkaline region. The potential origin of these kinetically influential

  16. Proton slippage in cytochrome c oxidase of Paracoccus denitrificans. Membrane-potential measurements with the two-subunit and three-subunit enzyme.

    PubMed

    Steverding, D; Köhnke, D; Ludwig, B; Kadenbach, B

    1993-03-15

    Isolated cytochrome c oxidase from Paracoccus denitrificans, containing either two or three subunits, was reconstituted into liposomes and the membrane potential was measured at different rates of respiration using a triphenylmethylphosponium bromide electrode. Both enzymes revealed a non-linear increase of the membrane potential with increasing respiratory rates. The ratios of the respiratory rates of the two proton pumps decreased with increasing membrane potential, suggesting slippage of proton pumping, as has been shown before with two cytochrome c oxidases from bovine heart, differing in H+/e- stoichiometries due to chemical modification [Steverding, D. & Kadenbach, B. (1991) J. Biol. Chem. 266, 8097-8101]. The data suggest that slippage of proton pumping represents an intrinsic property of cytochrome c oxidase associated with the two catalytic subunits, I and II.

  17. Castellaniella gen. nov., to accommodate the phylogenetic lineage of Alcaligenes defragrans, and proposal of Castellaniella defragrans gen. nov., comb. nov. and Castellaniella denitrificans sp. nov.

    PubMed

    Kämpfer, P; Denger, K; Cook, A M; Lee, S-T; Jäckel, U; Denner, E B M; Busse, H-J

    2006-04-01

    Comparative 16S rRNA gene sequence analysis indicates that two distinct sublineages exist within the genus Alcaligenes: the Alcaligenes faecalis lineage, comprising Alcaligenes aquatilis and A. faecalis (with the three subspecies A. faecalis subsp. faecalis, A. faecalis subsp. parafaecalis and A. faecalis subsp. phenolicus), and the Alcaligenes defragrans lineage, comprising A. defragrans. This phylogenetic discrimination is supported by phenotypic and chemotaxonomic differences. It is proposed that the A. defragrans lineage constitutes a distinct genus, for which the name Castellaniella gen. nov. is proposed. The type strain for Castellaniella defragrans gen. nov., comb. nov. is 54PinT (=CCUG 39790T = CIP 105602T = DSM 12141T). Finally, on the basis of data from the literature and new DNA-DNA hybridization and phenotypic data, the novel species Castellaniella denitrificans sp. nov. (type strain NKNTAUT = DSM 11046T = CCUG 39541T) is proposed for two strains previously identified as strains of A. defragrans.

  18. Crystallization and preliminary X-ray analysis of the periplasmic nitrate reductase (NapA-NapB complex) from Rhodobacter sphaeroides f. sp. denitrificans.

    PubMed

    Pignol, D; Adriano, J M; Fontecilla-Camps, J C; Sabaty, M

    2001-12-01

    The periplasmic nitrate reductase of Rhodobacter sphaeroides f. sp. denitrificans is a heterodimer responsible for the first step of reduction in the denitrification process by the conversion of nitrate to nitrite. It consists of a 91 kDa molybdenum-containing catalytic subunit (NapA) and a 17 kDa dihaem cytochrome c (NapB). Crystals of the NapA-NapB complex were obtained by the vapour-diffusion method using ammonium sulfate as precipitant. They belong to the P6(1)22 space group, with unit-cell parameters a = b = 151.9, c = 255.8 A, and contain a single complex in the asymmetric unit. A complete native data set was collected at a synchrotron source to 3.1 A resolution.

  19. Expression of plastocyanin and cytochrome f of the cyanobacterium Phormidium laminosum in Escherichia coli and Paracoccus denitrificans and the role of leader peptides.

    PubMed

    Schlarb, B G; Wagner, M J; Vijgenboom, E; Ubbink, M; Bendall, D S; Howe, C J

    1999-07-08

    The gene for plastocyanin from the cyanobacterium Phormidium laminosum was successfully expressed in Escherichia coli. Expression of the gene for cytochrome f resulted in the production of holocytochrome f in the periplasmic space of E. coli, but the yield was low. Expression in Paracoccus denitrificans yielded no holoprotein. When the region encoding the cytochrome f leader sequence was replaced with more typical bacterial leader sequences (those from the P. laminosum plastocyanin gene and the Paracoccus versutus cytochrome c-550 gene), much higher yields were consistently obtained in both species. Overexpressed proteins were compared to those isolated from P. laminosum and found to be identical in mass, isoelectric point, redox midpoint potential and (for plastocyanin) 1H-NMR spectrum.

  20. Redox dependent changes at the heme propionates in cytochrome c oxidase from Paracoccus denitrificans: direct evidence from FTIR difference spectroscopy in combination with heme propionate 13C labeling.

    PubMed

    Behr, J; Hellwig, P; Mäntele, W; Michel, H

    1998-05-19

    Specific isotope labeling at the carboxyl groups of the four heme propionates of cytochrome c oxidase from Paracoccus denitrificans was used in order to assign signals observed in electrochemically induced redox Fourier transform infrared (FTIR) difference spectra of this enzyme. For this purpose, the hemA gene of the P. denitrificans strain PD1222, coding for 5-aminolevulinate synthase, was deleted by partial replacement with a kanamycin resistance cartridge, resulting in a stable 5-aminolevulinic acid (ALA) auxotrophy. Normal growth of this deficient strain and cytochrome c oxidase yield comparable to that of P. dentrificans wild-type strain PD1222 could be obtained by supplementation with 0.1 mM ALA in the growth medium. Visible spectra and reduced-minus-oxidized FTIR spectra showed that the purified cytochrome c oxidase had spectral characteristics identical to those of the wild-type enzyme. The decrease of a negative signal at 1676 cm-1 in the reduced-minus-oxidized FTIR difference spectra of the 13C-labeled cytochrome c oxidase in comparison to those of the unlabeled protein allowed the assignment of this signal to a COOH vibration mode of at least one of the four heme propionates. Moreover, a negative band at approximately 1570 cm-1 shifted to smaller wavenumbers in the spectra of the 13C-labeled enzyme in comparison to the spectra of the unlabeled enzyme and was thus assigned to contributions from an antisymmetric COO- mode of one or more of the four heme propionates. Additionally, a positive signal at 1538 cm-1 shifted to approximately 1500 cm-1 in the spectra of the isotopically labeled protein and was therefore assigned to at least one antisymmetric COO- mode of the heme propionates. A negative signal at 1390 cm-1, which has been shifted to 1360 cm-1 in the spectra of the 13C-labeled enzyme, is due to a symmetric COO- mode from at least one heme propionate. These results suggest that at least two of the four heme propionates in cytochrome c oxidase

  1. Structural Stability, Transitions, and Interactions within SoxYZCD-Thiosulphate from Sulfurimonas denitrificans: An In Silico Molecular Outlook for Maintaining Environmental Sulphur Cycle

    PubMed Central

    Banerjee, Arundhati

    2016-01-01

    Thiosulphate oxidation (an essential mechanism) serves to maintain the global sulphur cycle. Earlier experimental and computational studies dealt with environmental thiosulphate oxidation but none dealt with thiosulphate oxidation from deep ocean belts. Wet-laboratory experimental research shows that epsilon-proteobacteria Sulfurimonas denitrificans possess sox (sulphur-oxidizing) operon and perform thiosulphate oxidation efficiently underneath the oceans. From this specific sox operon, SoxCD complex recycles the thiosulphate-bound SoxY from SoxYZ complex to balance the environmental sulphur cycle. So, four chief proteins were variedly modeled and relevant simulated interactive structures were obtained. The final simulated tetraprotein complex (SoxYZCD) from docked SoxYZ and SoxCD complexes was disclosed to be a highly interactive one with predominant ionic residues. Free energy of folding, solvent accessibility, and conformational shifts (coil-like conformation to helices and sheets) were observed in SoxYZ complex after interacting with SoxCD. The stability of the complex (SoxYZCD) after simulation was also observed through the electrostatic surface potential values. These evaluations were rationalized via biostatistics. This aids SoxCD for recycling SoxY along with thiosulphate, which remains interconnected by four H-bonds with SoxY. Therefore, this novel exploration is endowed with the detailed molecular viewpoint for maintaining the sulphur cycle (globally) including the ocean belts. PMID:27777586

  2. Transcriptional regulation, metal binding properties and structure of Pden1597, an unusual zinc transport protein from Paracoccus denitrificans

    SciTech Connect

    Handali, Melody; Neupane, Durga P.; Roychowdhury, Hridindu; Yukl, Erik T.

    2015-03-18

    Here, ATP-binding cassette (ABC) transporters of the cluster 9 family are ubiquitous among bacteria and essential for acquiring Zn2+ and Mn2+ from the environment or, in the case of pathogens, from the host. These rely on a substrate-binding protein (SBP) to coordinate the relevant metal with high affinity and specificity and subsequently release it to a membrane permease for translocation into the cytoplasm. Although a number of cluster 9 SBP structures have been determined, the structural attributes conferring Zn2+ or Mn2+ specificity remain ambiguous. Here we describe the gene expression profile, in vitro metal binding properties, and crystal structure of a new cluster 9 SBP from Paracoccus denitrificans we have called AztC. Although all of our results strongly indicate Zn2+ over Mn2+ specificity, the Zn2+ ion is coordinated by a conserved Asp residue only observed to date as a metal ligand in Mn2+-specific SBPs. The unusual sequence properties of this protein are shared among close homologues, including members from the human pathogens Klebsiella pneumonia and Enterobacter aerogenes, and would seem to suggest a subclass of Zn2+-specific transporters among the cluster 9 family. In any case, the unusual coordination environment of AztC expands the already considerable range of those available to Zn2+-specific SBPs and highlights the presence of a His-rich loop as the most reliable indicator of Zn2+ specificity.

  3. IncP-1β plasmids of Comamonas sp. and Delftia sp. strains isolated from a wastewater treatment plant mediate resistance to and decolorization of the triphenylmethane dye crystal violet.

    PubMed

    Stolze, Yvonne; Eikmeyer, Felix; Wibberg, Daniel; Brandis, Gerrit; Karsten, Christina; Krahn, Irene; Schneiker-Bekel, Susanne; Viehöver, Prisca; Barsch, Aiko; Keck, Matthias; Top, Eva M; Niehaus, Karsten; Schlüter, Andreas

    2012-08-01

    The application of toxic triphenylmethane dyes such as crystal violet (CV) in various industrial processes leads to large amounts of dye-contaminated sludges that need to be detoxified. Specific bacteria residing in wastewater treatment plants (WWTPs) are able to degrade triphenylmethane dyes. The objective of this work was to gain insights into the genetic background of bacterial strains capable of CV degradation. Three bacterial strains isolated from a municipal WWTP harboured IncP-1β plasmids mediating resistance to and decolorization of CV. These isolates were assigned to the genera Comamonas and Delftia. The CV-resistance plasmid pKV29 from Delftia sp. KV29 was completely sequenced. In addition, nucleotide sequences of the accessory regions involved in conferring CV resistance were determined for plasmids pKV11 and pKV36 from the other two isolates. Plasmid pKV29 contains typical IncP-1β backbone modules that are highly similar to those of previously sequenced IncP-1β plasmids that confer antibiotic resistance, degradative capabilities or mercury resistance. The accessory regions located between the conjugative transfer (tra) and mating pair formation modules (trb) of all three plasmids analysed share common modules and include a triphenylmethane reductase gene, tmr, that is responsible for decolorization of CV. Moreover, these accessory regions encode other enzymes that are dispensable for CV degradation and hence are involved in so-far-unknown metabolic pathways. Analysis of plasmid-mediated degradation of CV in Escherichia coli by ultra-high-performance liquid chromatography-electrospray ionization-quadrupole-time-of-flight MS revealed that leuco crystal violet was the first degradation product. Michler's ketone and 4-dimethylaminobenzaldehyde appeared as secondary degradation metabolites. Enzymes encoded in the E. coli chromosome seem to be responsible for cleavage of leuco crystal violet. Plasmid-mediated degradation of triphenylmethane dyes such as CV

  4. Identification and characterization of the LysR-type transcriptional regulator HsdR for steroid-inducible expression of the 3α-hydroxysteroid dehydrogenase/carbonyl reductase gene in Comamonas testosteroni.

    PubMed

    Gong, Wenjie; Xiong, Guangming; Maser, Edmund

    2012-02-01

    3α-Hydroxysteroid dehydrogenase/carbonyl reductase (3α-HSD/CR) from Comamonas testosteroni is a key enzyme in steroid degradation in soil and water. 3α-HSD/CR gene (hsdA) expression can be induced by steroids like testosterone and progesterone. Previously, we have shown that the induction of hsdA expression by steroids is a derepression where steroidal inducers bind to two repressors, RepA and RepB, thereby preventing the blocking of hsdA transcription and translation, respectively (G. Xiong and E. Maser, J. Biol. Chem. 276:9961-9970, 2001; G. Xiong, H. J. Martin, and E. Maser, J. Biol. Chem. 278:47400-47407, 2003). In the present study, a new LysR-type transcriptional factor, HsdR, for 3α-HSD/CR expression in C. testosteroni has been identified. The hsdR gene is located 2.58 kb downstream from hsdA on the C. testosteroni ATCC 11996 chromosome with an orientation opposite that of hsdA. The hsdR gene was cloned and recombinant HsdR protein was produced, as was anti-HsdR polyclonal antibodies. While heterologous transformation systems revealed that HsdR activates the expression of the hsdA gene, electrophoresis mobility shift assays showed that HsdR specifically binds to the hsdA promoter region. Interestingly, the activity of HsdR is dependent on decreased repression by RepA. Furthermore, in vitro binding assays indicated that HsdR can come into contact with RNA polymerase. As expected, an hsdR knockout mutant expressed low levels of 3α-HSD/CR compared to that of wild-type C. testosteroni after testosterone induction. In conclusion, HsdR is a positive transcription factor for the hsdA gene and promotes the induction of 3α-HSD/CR expression in C. testosteroni.

  5. Construction of a biosensor mutant of Comamonas testosteroni for testosterone determination by cloning the EGFP gene downstream to the regulatory region of the 3,17β-HSD gene.

    PubMed

    Xiong, Guangming; Maser, Edmund

    2015-06-05

    Comamonas testosteroni (C. testosteroni) is able to catabolize a variety of steroids and polycyclic aromatic hydrocarbons. 3,17β-Hydroxysteroid dehydrogenase (3,17β-HSD) from C. testosteroni is a testosterone-inducible protein and a key enzyme in steroid degradation. 3,17β-HSD is a member of the short-chain dehydrogenase/reductase (SDR) superfamily. We found that a 2.4 kb regulatory DNA fragment upstream of the 3,17β-HSD gene (βhsd) responds to steroids and triggers βhsd gene induction. To exploit this cis-acting regulatory element for a steroid determination system, plasmids pK2.4-EGFP-4 and pBB2.4-EGFP-8 were constructed. Both plasmids contain the EGFP gene fused downstream to a 2.4 kb DNA fragment from C. testosteroni. However, whereas pK2.4-EGFP-4 could integrate into the chromosomal DNA of C. testosteroni and knock out the βhsd gene promoter, pBB2.4-EGFP-8 could replicate in C. testosteroni cells as a free plasmid DNA. After integration of pK2.4-EGFP-4 into the βhsd gene promoter, 3,17β-HSD expression could not be induced such that EGFP expression in the mutant cells was at low levels. In contrast, in C. testosteroni cells transformed with pBB2.4-EGFP-8 the expression of EGFP was induced with testosterone. Our results showed that fluorescence counts (relative fluorescence units; RFU) increased in parallel with testosterone concentrations. Of note, estradiol and cholesterol could not induce the EGFP reporter gene. In summary, this new biosensor system might be used for the specific determination of testosterone.

  6. An elementary reaction step of the proton pump is revealed by mutation of tryptophan-164 to phenylalanine in cytochrome c oxidase from Paracoccus denitrificans.

    PubMed

    Ribacka, Camilla; Verkhovsky, Michael I; Belevich, Ilya; Bloch, Dmitry A; Puustinen, Anne; Wikström, Mårten

    2005-12-20

    Cytochrome c oxidase couples reduction of dioxygen to water to translocation of protons over the inner mitochondrial or bacterial membrane. A likely proton acceptor for pumped protons is the Delta-propionate of heme a(3), which may receive the proton via water molecules from a conserved glutamic acid (E278 in subunit I of the Paracoccus denitrificans enzyme) and which receives a hydrogen bond from a conserved tryptophan, W164. Here, W164 was mutated to phenylalanine (W164F) to further explore the role of the heme a(3) Delta-propionate in proton translocation. FTIR spectroscopy showed changes in vibrations possibly attributable to heme propionates, and the midpoint redox potential of heme a(3) decreased by approximately 50 mV. The reaction of the oxidized W164F enzyme with hydrogen peroxide yielded substantial amounts of the intermediate F' even at high pH, which suggests that the mutation rearranges the local electric field in the binuclear center that controls the peroxide reaction. The steady-state proton translocation stoichiometry of the W164F enzyme dropped to approximately 0.5 H(+)/e(-) in cells and reconstituted proteoliposomes. Time-resolved electrometric measurements showed that when the fully reduced W164F enzyme reacted with O(2), the membrane potential generated in the fast phase of this reaction was far too small to account either for full proton pumping or uptake of a substrate proton from the inside of the proteoliposomes. Time-resolved optical spectroscopy showed that this fast electrometric phase occurred with kinetics corresponding to the transition from state A to P(R), whereas the subsequent transition to the F state was strongly delayed. This is due to a delay of reprotonation of E278 via the D-pathway, which was confirmed by observation of a slowed rate of Cu(A) oxidation and which explains the small amplitude of the fast charge transfer phase. Surprisingly, the W164F mutation thus mimics a weak block of the D-pathway, which is interpreted as

  7. Poly(3-Hydroxybutyrate) Production from Glycerol by Zobellella denitrificans MW1 via High-Cell-Density Fed-Batch Fermentation and Simplified Solvent Extraction▿

    PubMed Central

    Ibrahim, Mohammad H. A.; Steinbüchel, Alexander

    2009-01-01

    Industrial production of biodegradable polyesters such as polyhydroxyalkanoates is hampered by high production costs, among which the costs for substrates and for downstream processing represent the main obstacles. Inexpensive fermentable raw materials such as crude glycerol, an abundant by-product of the biodiesel industry, have emerged to be promising carbon sources for industrial fermentations. In this study, Zobellella denitrificans MW1, a recently isolated bacterium, was used for the production of poly(3-hydroxybutyrate) (PHB) from glycerol as the sole carbon source. Pilot-scale fermentations (42-liter scale) were conducted to scale up the high PHB accumulation capability of this strain. By fed-batch cultivation, at first a relatively high cell density (29.9 ± 1.3 g/liter) was obtained during only a short fermentation period (24 h). However, the PHB content was relatively low (31.0% ± 4.2% [wt/wt]). Afterwards, much higher concentrations of PHB (up to 54.3 ± 7.9 g/liter) and higher cell densities (up to 81.2 ± 2.5 g/liter) were obtained by further fed-batch optimization in the presence of 20 g/liter NaCl, with optimized feeding of glycerol and ammonia to support both cell growth and polymer accumulation over a period of 50 h. A high specific growth rate (0.422/h) and a short doubling time (1.64 h) were attained. The maximum PHB content obtained was 66.9% ± 7.6% of cell dry weight, and the maximum polymer productivity and substrate yield coefficient were 1.09 ± 0.16 g/liter/h and 0.25 ± 0.04 g PHB/g glycerol, respectively. Furthermore, a simple organic solvent extraction process was employed for PHB recovery during downstream processing: self-flotation of cell debris after extraction of PHB with chloroform allowed a convenient separation of a clear PHB-solvent solution from the cells. Maximum PHB recovery (85.0% ± 0.10% [wt/wt]) was reached after 72 h of extraction with chloroform at 30°C, with a polymer purity of 98.3% ± 1.3%. PMID:19666728

  8. Poly(3-hydroxybutyrate) production from glycerol by Zobellella denitrificans MW1 via high-cell-density fed-batch fermentation and simplified solvent extraction.

    PubMed

    Ibrahim, Mohammad H A; Steinbüchel, Alexander

    2009-10-01

    Industrial production of biodegradable polyesters such as polyhydroxyalkanoates is hampered by high production costs, among which the costs for substrates and for downstream processing represent the main obstacles. Inexpensive fermentable raw materials such as crude glycerol, an abundant by-product of the biodiesel industry, have emerged to be promising carbon sources for industrial fermentations. In this study, Zobellella denitrificans MW1, a recently isolated bacterium, was used for the production of poly(3-hydroxybutyrate) (PHB) from glycerol as the sole carbon source. Pilot-scale fermentations (42-liter scale) were conducted to scale up the high PHB accumulation capability of this strain. By fed-batch cultivation, at first a relatively high cell density (29.9 +/- 1.3 g/liter) was obtained during only a short fermentation period (24 h). However, the PHB content was relatively low (31.0% +/- 4.2% [wt/wt]). Afterwards, much higher concentrations of PHB (up to 54.3 +/- 7.9 g/liter) and higher cell densities (up to 81.2 +/- 2.5 g/liter) were obtained by further fed-batch optimization in the presence of 20 g/liter NaCl, with optimized feeding of glycerol and ammonia to support both cell growth and polymer accumulation over a period of 50 h. A high specific growth rate (0.422/h) and a short doubling time (1.64 h) were attained. The maximum PHB content obtained was 66.9% +/- 7.6% of cell dry weight, and the maximum polymer productivity and substrate yield coefficient were 1.09 +/- 0.16 g/liter/h and 0.25 +/- 0.04 g PHB/g glycerol, respectively. Furthermore, a simple organic solvent extraction process was employed for PHB recovery during downstream processing: self-flotation of cell debris after extraction of PHB with chloroform allowed a convenient separation of a clear PHB-solvent solution from the cells. Maximum PHB recovery (85.0% +/- 0.10% [wt/wt]) was reached after 72 h of extraction with chloroform at 30 degrees C, with a polymer purity of 98.3% +/- 1.3%.

  9. Nucleotide sequence of a Pseudomonas denitrificans 5.4-kilobase DNA fragment containing five cob genes and identification of structural genes encoding S-adenosyl-L-methionine: uroporphyrinogen III methyltransferase and cobyrinic acid a,c-diamide synthase.

    PubMed Central

    Crouzet, J; Cauchois, L; Blanche, F; Debussche, L; Thibaut, D; Rouyez, M C; Rigault, S; Mayaux, J F; Cameron, B

    1990-01-01

    A 5.4-kilobase DNA fragment carrying Pseudomonas denitrificans cob genes has been sequenced. The nucleotide sequence and genetic analysis revealed that this fragment carries five different cob genes (cobA to cobE). Four of these genes present the characteristics of translationally coupled genes. cobA has been identified as the structural gene of S-adenosyl-L-methionine:uroporphyrinogen III methyltransferase (SUMT) because the encoded protein has the same NH2 terminus and molecular weight as those determined for the purified SUMT. For the same reasons the cobB gene was shown to be the structural gene for cobyrinic acid a,c-diamide synthase. Genetic and biochemical data concerning cobC and cobD mutants suggest that the products of these genes are involved in the conversion of cobyric acid to cobinamide. PMID:2211520

  10. Sequence of the bphD gene encoding 2-hydroxy-6-oxo-(phenyl/chlorophenyl)hexa-2,4-dienoic acid (HOP/cPDA) hydrolase involved in the biphenyl/polychlorinated biphenyl degradation pathway in Comamonas testosteroni: evidence suggesting involvement of Ser112 in catalytic activity.

    PubMed

    Ahmad, D; Fraser, J; Sylvestre, M; Larose, A; Khan, A; Bergeron, J; Juteau, J M; Sondossi, M

    1995-04-14

    The nucleotide sequence of bphD, encoding 2-hydroxy-6-oxo-(phenyl/chlorophenyl)hexa-2,4-dienoic acid hydrolase involved in the biphenyl/polychlorinated biphenyl degradation pathway of Comamonas testosteroni strain B-356, was determined. Comparison of the deduced amino-acid sequence with published sequences led to the identification of a 'lipase box', containing a consensus pentapeptide sequence GlyXaaSerXaaGly. This suggested that the mechanism of action of this enzyme may involve an Asp-Ser-His catalytic triad similar to that of classical lipases and serine hydrolases. Further biochemical and genetic evidence for the active-site involvement of Ser112 was obtained by showing that a semipurified enzyme was inhibited by PMSF, a classic inhibitor of serine hydrolases, and by site-directed Ser112-->Ala mutagenesis.

  11. Identification of 9,17-Dioxo-1,2,3,4,10,19-Hexanorandrostan-5-oic Acid, 4-Hydroxy-2-Oxohexanoic Acid, and 2-Hydroxyhexa-2,4-Dienoic Acid and Related Enzymes Involved in Testosterone Degradation in Comamonas testosteroni TA441

    PubMed Central

    Horinouchi, Masae; Hayashi, Toshiaki; Koshino, Hiroyuki; Kurita, Tomokazu; Kudo, Toshiaki

    2005-01-01

    Comamonas testosteroni TA441 utilizes testosterone via aromatization of the A ring followed by meta-cleavage of the ring. The product of the meta-cleavage reaction, 4,5-9,10-diseco-3-hydroxy-5,9,17-trioxoandrosta-1(10),2-dien-4-oic acid, is degraded by a hydrolase, TesD. We directly isolated and identified two products of TesD as 9,17-dioxo-1,2,3,4,10,19-hexanorandrostan-5-oic acid and (2Z,4Z)-2-hydroxyhexa-2,4-dienoic acid. The latter was a pure 4Z isomer. 2-Hydroxyhexa-2,4-dienoic acid was converted by a hydratase, TesE, and the product isolated from the reaction solution was identified as 2-hydroxy-4-hex-2-enolactone, indicating the direct product of TesE to be 4-hydroxy-2-oxohexanoic acid. PMID:16151114

  12. Phylogenetic origins of the plant mitochondrion based on a comparative analysis of 5S ribosomal RNA sequences

    NASA Technical Reports Server (NTRS)

    Villanueva, E.; Delihas, N.; Luehrsen, K. R.; Fox, G. E.; Gibson, J.

    1985-01-01

    The complete nucleotide sequences of 5S ribosomal RNAs from Rhodocyclus gelatinosa, Rhodobacter sphaeroides, and Pseudomonas cepacia were determined. Comparisons of these 5S RNA sequences show that rather than being phylogenetically related to one another, the two photosynthetic bacterial 5S RNAs share more sequence and signature homology with the RNAs of two nonphotosynthetic strains. Rhodobacter sphaeroides is specifically related to Paracoccus denitrificans and Rc. gelatinosa is related to Ps. cepacia. These results support earlier 16S ribosomal RNA studies and add two important groups to the 5S RNA data base. Unique 5S RNA structural features previously found in P. denitrificans are present also in the 5S RNA of Rb. sphaeroides; these provide the basis for subdivisional signatures. The immediate consequence of obtaining these new sequences is that it is possible to clarify the phylogenetic origins of the plant mitochondrion. In particular, a close phylogenetic relationship is found between the plant mitochondria and members of the alpha subdivision of the purple photosynthetic bacteria, namely, Rb. sphaeroides, P. denitrificans, and Rhodospirillum rubrum.

  13. The designated type strain of Pseudomonas halophila Fendrich 1989 is DSM 3051, the designated type strain of Halovibrio variabilis Fendrich 1989 is DSM 3050, the new name Halomonas utahensis (Fendrich 1989) Sorokin and Tindall 2006 is created for the species represented by DSM 3051 when treated as a member of the genus Halomonas, the combination Halomonas variabilis (Fendrich 1989) Dobson and Franzmann 1996 is rejected, and the combination Halovibrio denitrificans Sorokin et al. 2006 is validly published with an emendation of the description of the genus Halovibrio Fendrich 1989 emend. Sorokin et al. 2006. Opinion 93. Judicial Commission of the International Committee on Systematics of Prokaryotes.

    PubMed

    Tindall, B J

    2014-10-01

    The Judicial Commission affirms that, according to information presented to it, the designated type strain of Pseudomonas halophila Fendrich 1989 is DSM 3051 (replacing DSM 3050) and the designated type strain of Halovibrio variabilis Fendrich 1989 is DSM 3050 (replacing DSM 3051). A new name, Halomonas utahensis (Fendrich 1989) Sorokin and Tindall 2006 nom. nov., is created for the species represented by DSM 3051 when treated as a member of the genus Halomonas, because the combination Halomonas halophila (Quesada et al. 1984) Dobson and Franzmann 1996 has priority based on the fact that the epithet halophila in the combination Halomonas halophila (Quesada et al. 1984) Dobson and Franzmann 1996 ( BASOYNM: Deleya halophila Quesada et al. 1984) has priority over the epithet halophila should the taxon Pseudomonas halophila Fendrich 1989 be treated as a member of the genus Halomonas. The combination Halomonas variabilis (Fendrich 1989) Dobson and Franzmann 1996 is rejected. The combination Halovibrio denitrificans Sorokin et al. 2006 is validly published with an emendation of the description of the genus Halovibrio Fendrich 1989 emend. Sorokin et al. 2006.

  14. Photo-Initiated Electron Transfer Within the P. denitrificans Cytochrome bc1 Complex: The mobility of the Iron Sulfur Protein is modulated by the occupant of the Qo site†

    PubMed Central

    Havens, Jeffrey; Castellani, Michela; Kleinschroth, Thomas; Ludwig, Bernd; Durham, Bill; Millett, Francis

    2011-01-01

    Domain rotation of the Rieske iron-sulfur protein (ISP) between the cytochrome (cyt) b and cyt c1 redox centers plays a key role in the mechanism of the cyt bc1 complex. Electron transfer within the cyt bc1 complex of P. denitrificans was studied using a ruthenium dimer to rapidly photo-oxidize cyt c1 within 1 μs and initiate the reaction. In the absence of any added quinol or inhibitor of the bc1 complex at pH 8.0, electron transfer from reduced ISP to cyt c1 was biphasic with rate constants of k1f = 6300 ± 3000 s−1 and k1s = 640 ± 300 s−1 and amplitudes of 10 ± 3% and 16 ± 4 % of the total amount of cyt c1 photooxidized. Upon addition of any of the Pm type inhibitors MOA-stilbene, myxothiazol, or azoxystrobin to cyt bc1 in the absence of quinol, the total amplitude increased 2-fold, consistent with a decrease in redox potential of the ISP. In addition, the relative amplitude of the fast phase increased significantly, consistent with a change in the dynamics of the ISP domain rotation. In contrast, addition of the Pf type inhibitors JG-144 and famoxadone decreased the rate constant k1f by 5 to 10-fold, and increased the amplitude over 2-fold. Addition of quinol substrate in the absence of inhibitors led to a two-fold increase in the amplitude of the k1f phase. The effect of QH2 on the kinetics of electron transfer from reduced ISP to cyt c1 was thus similar to that of the Pm inhibitors and very different from that of the Pf inhibitors. The current results indicate that the species occupying the Qo site has a significant conformational influence on the dynamics of the ISP domain rotation. PMID:22026826

  15. Pyrite-based autotrophic denitrification for remediation of nitrate contaminated groundwater.

    PubMed

    Pu, Jiaoyang; Feng, Chuanping; Liu, Ying; Li, Rui; Kong, Zhe; Chen, Nan; Tong, Shuang; Hao, Chunbo; Liu, Ye

    2014-12-01

    In this study, pyrite-based denitrification using untreated pyrite (UP) and acid-pretreated pyrite (AP) was evaluated as an alternative to elemental sulfur based denitrification. Pyrite-based denitrification resulted in a favorable nitrate removal rate constant (0.95 d(-1)), sulfate production of 388.00 mg/L, and a stable pH. The pretreatment of pyrite with acid led to a further increase in the nitrate removal rate constant (1.03 d(-1)) and reduction in initial sulfate concentration (224.25±7.50 mg/L). By analyzing the microbial community structure using Denaturing Gradient Gel Electrophoresis, it was confirmed that Sulfurimonas denitrificans (S. denitrificans) could utilize pyrite as an electron donor. A stable pH was observed over the entire experimental period, indicating that the use of a pH buffer reagent would not be necessary for pyrite-based denitrification. Therefore, pyrite could effectively replace elemental sulfur as an electron donor in autotrophic denitrification for nitrate-contaminated groundwater remediation.

  16. Isolation and characterization of the moxJ, moxG, moxI, and moxR genes of Paracoccus denitrificans: inactivation of moxJ, moxG, and moxR and the resultant effect on methylotrophic growth.

    PubMed Central

    Van Spanning, R J; Wansell, C W; De Boer, T; Hazelaar, M J; Anazawa, H; Harms, N; Oltmann, L F; Stouthamer, A H

    1991-01-01

    By using the moxF gene encoding the large fragment of methanol dehydrogenase as a probe, a downstream linked chromosomal fragment was isolated from a genomic bank of Paracoccus denitrificans. The nucleotide sequence of the fragment was determined and revealed the 3' part of moxF, four additional open reading frames, and the 5' part of a sixth one. The organization and deduced amino acid sequences of the first three frames downstream from moxF were found to be largely homologous to the moxJ, moxG, and moxI gene products of Methylobacterium extorquens AM1. Directly downstream from these three genes, a new mox gene was identified. The gene is designated moxR. By using the suicide vector pGRPd1, the moxJ, moxG, and moxR genes were inactivated by the insertion of a kanamycin resistance gene. Subsequently, suicide vector pRVS1 was used to replace the marker genes in moxJ and moxG for unmarked deletions made in vitro. As a result, the three insertion strains as well as the two unmarked mutant strains were unable to grow on methanol, even in the presence of pyrroloquinoline quinone. Growth on succinate and on methylamine was not affected. In all five mutant strains, synthesis of the large subunit of methanol dehydrogenase and of inducible cytochrome c553i was observed. The moxJ and moxG insertion mutant strains were unable to synthesize both the cytochrome c551i and the small subunit of methanol dehydrogenase, and this lack of synthesis was attended by the loss of methanol dehydrogenase activity. The moxJ deletion mutant strain partly synthesized the latter two proteins, cytochrome c551i. Partial synthesis of the small subunit of methanol dehydrogenase observed with the latter strain was attended by a corresponding extent of methanol dehydrogenase activity. The moxR insertion mutant strain was shown to synthesize cytochrome c551i as well as the large and small subunits of methanol dehydrogenase, but no methanol dehydrogenase activity was observed. The results show that

  17. [Study on drug sensitivity against Comamonas testosteroni by Kirby-Bauer disk diffusion method].

    PubMed

    Kong, Changsheng; Chen, Jun; Zou, Xiaoyan; Zhang, Yi; Zhu, Lingna

    2016-08-01

    目的:用无临床实验室标准化研究所(Clinical and Laboratory Standards Institute,CLSI)解释标准的Kirby-Bauer(K-B)法和有CLSI解释标准的最低抑菌浓度(minimum inhibitory concentration,MIC)法分别测定睾丸酮丛毛单胞菌的耐药性情况,评价K-B法用于睾丸酮丛毛单胞菌敏感性检测的临床应用价值。方法:用K-B法、MIC法测定睾丸酮丛毛单胞菌对哌拉西林、头孢吡肟、哌拉西林/他唑巴坦、亚胺培南、美洛培南、阿米卡星、庆大霉素、妥布霉素、头孢他啶、环丙沙星的敏感性,K-B法暂借铜绿假单胞菌的解释标准,并对两种方法相互间的符合情况进行比较。结果:K-B法、MIC法检测哌拉西林、头孢吡肟比较,完全符合率97.4%,部分符合率2.6%;检测哌拉西林/他唑巴坦、亚胺培南、美洛培南比较,完全符合率100%;检测阿米卡星、庆大霉素、妥布霉素比较,完全符合率94.7%,部分符合率5.3%;检测头孢他啶比较,完全符合率97.4%,部分符合率2.6%;检测环丙沙星比较,完全符合率86.8%,部分符合率10.6%,完全不符合率2.6%。结论:两种药敏试验方法得出的结果具有高度的一致性。微生物实验室用K-B法对睾丸酮丛毛单胞菌的药敏检测可仅报告实验检测结果,而不报药敏检测解释结果。.

  18. Simultaneous bioreduction of nitrate and chromate using sulfur-based mixotrophic denitrification process.

    PubMed

    Sahinkaya, Erkan; Kilic, Adem; Calimlioglu, Beste; Toker, Yasemin

    2013-11-15

    This study aims at evaluating simultaneous chromate and nitrate reduction using sulfur-based mixotrophic denitrification process in a column reactor packed with elemental sulfur and activated carbon. The reactor was supplemented with methanol at C/N ratio of 1.33 or 2. Almost complete denitrification was achieved at influent NO3(-)-N and Cr(VI) concentrations of 75 mg/L and 10mg/L, respectively, and 3.7h HRT. Maximum denitrification rate was 0.5 g NO3(-)-N/(L.d) when the bioreactor was fed with 75 mg/L NO3(-)-N, 150 mg/L methanol and 10mg/L Cr(VI). The share of autotrophic denitrification was between 12% and 50% depending on HRT, C/N ratio and Cr(VI) concentration. Effluent total chromium was below 50 μg/L provided that influent Cr(VI) concentration was equal or below 5mg/L. DGGE results showed stable microbial community throughout the operation and the presence of sulfur oxidizing denitrifying bacteria (Thiobacillus denitrificans) and Cr(VI) reducing bacteria (Exiguobacterium spp.) in the column bed.

  19. Removal of methyl acrylate by ceramic-packed biotrickling filter and their response to bacterial community.

    PubMed

    Wu, Hao; Yin, Zhenhao; Quan, Yue; Fang, Yingyu; Yin, Chengri

    2016-06-01

    Methyl acrylate is a widely used raw chemical materials and it is toxic in humans. In order to treat the methyl acrylate waste gas, a 3-layer BTF packed with ceramic particles and immobilized with activated sludge was set up. The BTF exhibited excellent removal efficiency that no methyl acrylate could be detected when EBRT was larger than 266s and inlet concentration was lower than 0.19g/m(3). The 1st layer performed the best at fixed inlet concentration of 0.42g/m(3). PCR combined with DGGE was performed to detect the differences in different layers of the BTF. Phylum Proteobacteria (e.g. α-, β-, γ-, δ-) was predominantly represented in the bacterial community, followed by Actinobacteria and Firmicutes. Desulfovibrio gigas, Variovorax paradoxus, Dokdonella koreensis, Pseudoxanthomonas suwonensis, Azorhizobium caulinodans, Hyphomicrobium denitrificans, Hyphomicrobium sp. and Comamonas testosteroni formed the bacteria community to treat methyl acrylate waste gas in the BTF.

  20. Catalysis by Methylamine Dehydrogenase and Electron Transfer to Amicyanin and Cytochrome C(551I) from Paracoccus Denitrificans.

    NASA Astrophysics Data System (ADS)

    Brooks, Harold Burns

    1995-01-01

    The quinoprotein methylamine dehydrogenase (MADH), a type I copper protein, amicyanin, and cytochrome c _{55li} form a physiologic ternary complex (Chen et al. (1994) Science 264, 86-90) in which electrons are transferred from tryptophan tryptophylquinone to copper to heme. The reduction of MADH by rm H_3- and rm D_3 -methylamine, the reoxidation of MADH by amicyanin, and the reduction of cytochrome c_{55li } by reduced amicyanin in the presence of MADH have been studied by stopped-flow spectroscopy. When rm CD_3NH_2 was used as a substrate for MADH a deuterium kinetic isotope effect of 17.2 was measured for the hydrogen abstraction step. The maximum deuterium kinetic isotope effect that was measured in steady-state kinetic experiments was 3.0. The temperature dependencies of the rate constants for the reaction of methylamine with MADH were also determined. An iminosemiquinone intermediate for the oxidation of substrate-reduced MADH by amicyanin was detected using stopped-flow spectroscopy, and the presence of the substrate derived nitrogen was confirmed by electron spin echo envelope modulation (ESEEM) spectroscopy. Marcus theory, which was used to analyze the electron transfer reaction between the dithionite-generated redox forms of MADH and amicyanin, gave values of 218 kJ rm mol^{ -1} (2.3 eV) for the reorganizational energy (lambda ) and 11.6 rm cm^{-1} for the coupling rm (H_{AB}). In contrast, the oxidation of substrate-reduced MADH by amicyanin was a gated electron transfer reaction with values for DeltaH* of 76 kJ rm mol^ {-1} and DeltaS* of -41 J rm mol^{ -1} ^circ K^ {-1}. These studies are consistent with the formation of transient unstable intermediates preceeding electron transfer between MADH and amicyanin. Preliminary investigations of the ternary complex of MADH, amicyanin, and cytochrome c_{55li } suggest two distinct cytochrome c _{55li} binding sites on amicyanin. This conclusion is supported by the biphasic nature of the stopped -flow trace, the inhibition of the rm k^ {fast}_{obs} by MADH, and the ionic strength dependence of the two phases. The slow phase had a rate of 3.1 rm s^ {-1} which is consistent with electron transfer between amicyanin and cytochrome c_ {55li} within the ternary complex. The fast phase does not exhibit saturation behavior, must have an electron transfer rate greater than 1000 rm s^{-1}, and likely involves a complex of amicyanin and cytochrome c_{55li } near the hydrophobic patch of amicyanin.

  1. Using the bacterium, Paracoccus denitrificans and other 'runaway mitochondria' as classroom models for respiratory electron transport studies.

    PubMed

    Bolgiano, B; Davies, H C; Poole, R K

    1991-11-01

    Our suggestions for experiments demonstrating electron-transport-chain composition and reactions all exploit bacteria which can be prepared quickly, easily and cheaply from cells grown in Erlenmeyer flasks. While they have been designed from a cytochrome oxidase point of view using organisms of our own prejudice, strains containing mutations in other sites could be just as educational. Most bacteria that can grow aerobically have features in common with the mitochondrial respiratory chain. Because of the vital importance of oxygen utilization throughout most of evolution, and consequent conservation of electron-transport complexes and carriers, the teaching of bioenergetics, whether in the laboratory or lecture room, could benefit from the inclusion of micro-organisms in the curriculum.

  2. Role of S114 in the NADH-induced conformational change and catalysis of 3alpha-hydroxysteroid dehydrogenase/carbonyl reductase from Comamonas testosteroni.

    PubMed

    Chang, Yi-Hsun; Huang, Tzu-Jung; Chuang, Lea-Yea; Hwang, Chi-Ching

    2009-10-01

    3alpha-Hydroxysteroid dehydrogenase/carbonyl reductase reversibly catalyzes the oxidation of androsterone with NAD(+) to form androstanedione and NADH. In this study, we characterize the role of the conserved residue S114 in cofactor binding and catalysis, using site-directed mutagenesis, steady-state kinetics, fluorescence quenching and anisotropy measurements. The catalytic efficiency of V/K(NADH)Et for wild-type and S114A is 1.5 x10(7) and 3.8 x 10(3) M(-1) s(-1), respectively, suggesting that NADH association to wild-type and S114A mutant enzymes involves two steps, a bimolecular binding step and isomerization. The binding of NADH into a hydrophobic pocket in the active site of wild-type and S114A mutant enzymes restricts its motion and shields the fluorescence quenching from solvent, with an increase in the fluorescence intensity and a blue shift at the maximum wavelength. Furthermore, the binding of NADH leads to the protein fluorescence quenching, mainly due to fluorescence resonance energy transfer to NADH. S114A mutant enzyme decreases 3100-fold in V/Et with no apparent change in K(m) for substrates. Addition of NADH to S114A mutant enzyme induces a secondary structural change. These results suggest that S114 is important to maintain the correct conformation for the nucleotide binding and facilitate the reaction. Substitution of alanine for S114 eliminates the hydrogen bonding interaction with P185, causing a conformational change in a nonproductive binding of NADH and a significant loss of activity.

  3. Development and Use of Integrated Microarray-Based Genomic Technologies for Assessing Microbial Community Composition and Dynamics

    SciTech Connect

    Zhou, J.; Wu, L.; Gentry, T.; Schadt, C.; He, Z.; Li, X.

    2006-04-05

    To effectively monitor microbial populations involved in various important processes, a 50-mer-based oligonucleotide microarray was developed based on known genes and pathways involved in: biodegradation, metal resistance and reduction, denitrification, nitrification, nitrogen fixation, methane oxidation, methanogenesis, carbon polymer decomposition, and sulfate reduction. This array contains approximately 2000 unique and group-specific probes with <85% similarity to their non-target sequences. Based on artificial probes, our results showed that at hybridization conditions of 50 C and 50% formamide, the 50-mer microarray hybridization can differentiate sequences having <88% similarity. Specificity tests with representative pure cultures indicated that the designed probes on the arrays appeared to be specific to their corresponding target genes. Detection limits were about 5-10ng genomic DNA in the absence of background DNA, and 50-100ng ({approx}1.3{sup o} 10{sup 7} cells) in the presence background DNA. Strong linear relationships between signal intensity and target DNA and RNA concentration were observed (r{sup 2} = 0.95-0.99). Application of this microarray to naphthalene-amended enrichments and soil microcosms demonstrated that composition of the microflora varied depending on incubation conditions. While the naphthalene-degrading genes from Rhodococcus-type microorganisms were dominant in enrichments, the genes involved in naphthalene degradation from Gram-negative microorganisms such as Ralstonia, Comamonas, and Burkholderia were most abundant in the soil microcosms (as well as those for polyaromatic hydrocarbon and nitrotoluene degradation). Although naphthalene degradation is widely known and studied in Pseudomonas, Pseudomonas genes were not detected in either system. Real-time PCR analysis of 4 representative genes was consistent with microarray-based quantification (r{sup 2} = 0.95). Currently, we are also applying this microarray to the study of several

  4. Development and Use of Integrated Microarray-Based Genomic Technologies for Assessing Microbial Community Composition and Dynamics

    SciTech Connect

    J. Zhou; S.-K. Rhee; C. Schadt; T. Gentry; Z. He; X. Li; X. Liu; J. Liebich; S.C. Chong; L. Wu

    2004-03-17

    To effectively monitor microbial populations involved in various important processes, a 50-mer-based oligonucleotide microarray was developed based on known genes and pathways involved in: biodegradation, metal resistance and reduction, denitrification, nitrification, nitrogen fixation, methane oxidation, methanogenesis, carbon polymer decomposition, and sulfate reduction. This array contains approximately 2000 unique and group-specific probes with <85% similarity to their non-target sequences. Based on artificial probes, our results showed that at hybridization conditions of 50 C and 50% formamide, the 50-mer microarray hybridization can differentiate sequences having <88% similarity. Specificity tests with representative pure cultures indicated that the designed probes on the arrays appeared to be specific to their corresponding target genes. Detection limits were about 5-10ng genomic DNA in the absence of background DNA, and 50-100ng ({approx}1.3{sup o} 10{sup 7} cells) in the presence background DNA. Strong linear relationships between signal intensity and target DNA and RNA concentration were observed (r{sup 2} = 0.95-0.99). Application of this microarray to naphthalene-amended enrichments and soil microcosms demonstrated that composition of the microflora varied depending on incubation conditions. While the naphthalene-degrading genes from Rhodococcus-type microorganisms were dominant in enrichments, the genes involved in naphthalene degradation from Gram-negative microorganisms such as Ralstonia, Comamonas, and Burkholderia were most abundant in the soil microcosms (as well as those for polyaromatic hydrocarbon and nitrotoluene degradation). Although naphthalene degradation is widely known and studied in Pseudomonas, Pseudomonas genes were not detected in either system. Real-time PCR analysis of 4 representative genes was consistent with microarray-based quantification (r{sup 2} = 0.95). Currently, we are also applying this microarray to the study of several

  5. Development and Application of a Real-Time PCR Approach for Quantification of Uncultured Bacteria in the Central Baltic Sea

    PubMed Central

    Labrenz, Matthias; Brettar, Ingrid; Christen, Richard; Flavier, Sebastien; Bötel, Julia; Höfle, Manfred G.

    2004-01-01

    We have developed a highly sensitive approach to assess the abundance of uncultured bacteria in water samples from the central Baltic Sea by using a noncultured member of the “Epsilonproteobacteria” related to Thiomicrospira denitrificans as an example. Environmental seawater samples and samples enriched for the target taxon provided a unique opportunity to test the approach over a broad range of abundances. The approach is based on a combination of taxon- and domain-specific real-time PCR measurements determining the relative T. denitrificans-like 16S rRNA gene and 16S rRNA abundances, as well as the determination of total cell counts and environmental RNA content. It allowed quantification of T. denitrificans-like 16S rRNA molecules or 16S rRNA genes as well as calculation of the number of ribosomes per T. denitrificans-like cell. Every real-time measurement and its specific primer system were calibrated using environmental nucleic acids obtained from the original habitat for external standardization. These standards, as well as the respective samples to be measured, were prepared from the same DNA or RNA extract. Enrichment samples could be analyzed directly, whereas environmental templates had to be preamplified with general bacterial primers before quantification. Preamplification increased the sensitivity of the assay by more than 4 orders of magnitude. Quantification of enrichments with or without a preamplification step yielded comparable results. T. denitrificans-like 16S rRNA molecules ranged from 7.1 × 103 to 4.4 × 109 copies ml−1 or 0.002 to 49.7% relative abundance. T. denitrificans-like 16S rRNA genes ranged from 9.0 × 101 to 2.2 ×106 copies ml−1 or 0.01 to 49.7% relative abundance. Detection limits of this real-time-PCR approach were 20 16S rRNA molecules or 0.2 16S rRNA gene ml−1. The number of ribosomes per T. denitrificans-like cell was estimated to range from 20 to 200 in seawater and reached up to 2,000 in the enrichments. The

  6. Effects of plant growth promoting rhizobacteria (PGPR) on rooting and root growth of kiwifruit (Actinidia deliciosa) stem cuttings.

    PubMed

    Erturk, Yasar; Ercisli, Sezai; Haznedar, Ayhan; Cakmakci, Ramazan

    2010-01-01

    The effects of plant growth promoting rhizobacteria (PGPR) on the rooting and root growth of semi-hardwood and hardwood kiwifruit stem cuttings were investigated. The PGPR used were Bacillus RC23, Paenibacillus polymyxa RC05, Bacillus subtilis OSU142, Bacillus RC03, Comamonas acidovorans RC41, Bacillus megaterium RC01 and Bacillus simplex RC19. All the bacteria showed indole-3-acetic acid (IAA) producing capacity. Among the PGPR used, the highest rooting ratios were obtained at 47.50% for semi-hardwood stem cuttings from Bacillus RC03 and Bacillus simplex RC19 treatments and 42.50% for hardwood stem cuttings from Bacillus RC03. As well, Comamonas acidovorans RC41 inoculations indicated higher value than control treatments. The results suggest that these PGPR can be used in organic nursery material production and point to the feasibility of synthetic auxin (IBA) replacement by organic management based on PGPR.

  7. ENVIROMENTALLY BENIGN MITIGATION OF MICROBIOLOGICALLY INFLUENCED CORROSION (MIC)

    SciTech Connect

    J. Robert Paterek; Gemma Husmillo; Amrutha Daram; Vesna Trbovic

    2003-10-31

    The overall program objective is to develop and evaluate environmentally benign agents or products that are effective in the prevention, inhibition, and mitigation of microbially influenced corrosion (MIC) in the internal surfaces of metallic natural gas pipelines. The goal is to develop one or more environmentally benign (a.k.a. ''green'') products that can be applied to maintain the structure and dependability of the natural gas infrastructure. The technical approach for this quarter includes the application of the method of fractionation of the extracts by high performance liquid chromatography (HPLC); determination of antimicrobial activities of the new extracts and fractions using a growth inhibition assay, and evaluation of the extracts' ability to inhibit biofilm formation. We initiated the delivery system for these new biocides in the test cell and in mixtures of foam components and biocides/anti-biofilms. A total of 51 fractions collected by HPLC from crude extracts that were obtained from three varieties of Capsicum sp. (Serrano, Habanero, Chile de Arbol) were subjected to growth inhibition tests against two SRB strains, D. vulgaris and D. desulfuricans. Five fractions showed growth inhibition against both strains while seven inhibited D. desulfuricans only. The crude extracts did not show growth inhibition on both strains but were proven to be potent in preventing the formation of biofilm. Growth inhibition tests of the same set of crude extracts against Comamonas denitrificans did not show positive results. The fractions will be subjected to biofilm inhibition and dissociation assay as well. The delivery system to be evaluated first was foam. The ''foam pig'' components of surfactants and water were tested with the biocide addition. The first chemical and physical parameters to be tested were pH and surfactants. Tests using the fractionated pepper extracts are progressing rapidly. Gas chromatographic analysis on a number of fractions is underway

  8. Structural and functional characterization of a small chitin-active lytic polysaccharide monooxygenase domain of a multi-modular chitinase from Jonesia denitrificans.

    PubMed

    Mekasha, Sophanit; Forsberg, Zarah; Dalhus, Bjørn; Bacik, John-Paul; Choudhary, Swati; Schmidt-Dannert, Claudia; Vaaje-Kolstad, Gustav; Eijsink, Vincent G H

    2016-01-01

    Lytic polysaccharide monooxygenases (LPMOs) boost enzymatic depolymerization of recalcitrant polysaccharides, such as chitin and cellulose. We have studied a chitin-active LPMO domain (JdLPMO10A) that is considerably smaller (15.5 kDa) than all structurally characterized LPMOs so far and that is part of a modular protein containing a GH18 chitinase. The 1.55 Å resolution structure revealed deletions of interacting loops that protrude from the core β-sandwich scaffold in larger LPMO10s. Despite these deletions, the enzyme is active on alpha- and beta-chitin, and the chitin-binding surface previously described for larger LPMOs is fully conserved. JdLPMO10A may represent a minimal scaffold needed to catalyse the powerful LPMO reaction.

  9. Spectroscopic study on the communication between a heme a3 propionate, Asp399 and the binuclear center of cytochrome c oxidase from Paracoccus denitrificans.

    PubMed

    Hellwig, Petra; Böhm, Andreas; Pfitzner, Ute; Mäntele, Werner; Ludwig, Bernd

    2008-02-01

    The proton pumping mechanism of cytochrome c oxidase on a molecular level is highly disputed. Recently theoretical calculations and real time electron transfer measurements indicated the involvement of residues in the vicinity of the ring A propionate of heme a3, including Asp399 and the CuB ligands His 325, 326. In this study we probed the interaction of Asp399 with the binuclear center and characterize the protonation state of its side chain. Redox induced FTIR difference spectra of mutations at the site in direct comparison to wild type, indicate that below pH 5 Asp 399 displays signals typical for the deprotonation of the acidic residue with reduction of the enzyme. Interestingly at a pH higher than 5, no contributions from Asp 399 are evident. In order to probe the interaction of the site with the binuclear center we followed the rebinding of CO by infrared spectroscopy for mutations on residue Asp399 to Glu, Asn and Leu. Previously different CO conformers have been identified for bacterial cytochrome c oxidases, and its pH dependent behaviour discussed to be relevant for catalysis. Interestingly we observe the lack of this pH dependency and a strong influence on the observable conformers for all mutants studied here, clearly suggesting a communication of the site with the heme-copper center and the nearby histidine residues.

  10. GeoChip-based analysis of the microbial community functional structures in simultaneous desulfurization and denitrification process.

    PubMed

    Yu, Hao; Chen, Chuan; Ma, Jincai; Liu, Wenzong; Zhou, Jizhong; Lee, Duu-Jong; Ren, Nanqi; Wang, Aijie

    2014-07-01

    The elemental sulfur (S°) recovery was evaluated in the presence of nitrate in two development models of simultaneous desulfurization and denitrification (SDD) process. At the loading rates of 0.9 kg S/(m³·day) for sulfide and 0.4 kg N/(m³·day) for nitrate, S° conversion rate was 91.1% in denitrifying sulfide removal (DSR) model which was higher than in integrated simultaneous desulfurization and denitrification (ISDD) model (25.6%). A comprehensive analysis of functional diversity, structure and metabolic potential of microbial communities was examined in two models by using functional gene array (GeoChip 2.0). GeoChip data indicated that diversity indices, community structure, and abundance of functional genes were distinct between two models. Diversity indices (Simpson's diversity index (1/D) and Shannon-Weaver index (H')) of all detected genes showed that with elevated influent loading rate, the functional diversity decreased in ISDD model but increased in DSR model. In contrast to ISDD model, the overall abundance of dsr genes was lower in DSR model, while some functional genes targeting from nitrate-reducing sulfide-oxidizing bacteria (NR-SOB), such as Thiobacillus denitrificans, Sulfurimonas denitrificans, and Paracoccus pantotrophus were more abundant in DSR model which were highly associated with the change of S(0) conversion rate obtained in two models. The results obtained in this study provide additional insights into the microbial metabolic mechanisms involved in ISDD and DSR models, which in turn will improve the overall performance of SDD process.

  11. Assessment of bacterial diversity during composting of agricultural byproducts

    PubMed Central

    2013-01-01

    Background Composting is microbial decomposition of biodegradable materials and it is governed by physicochemical, physiological and microbiological factors. The importance of microbial communities (bacteria, actinomycetes and fungi) during composting is well established. However, the microbial diversity during composting may vary with the variety of composting materials and nutrient supplements. Therefore, it is necessary to study the diversity of microorganisms during composting of different agricultural byproducts like wheat bran, rice bran, rice husk, along with grass clippings and bulking agents. Here it has been attempted to assess the diversity of culturable bacteria during composting of agricultural byproducts. Results The culturable bacterial diversity was assessed during the process by isolating the most prominent bacteria. Bacterial population was found to be maximum during the mesophilic phase, but decreased during the thermophilic phase and declined further in the cooling and maturation phase of composting. The bacterial population ranged from 105 to 109 cfu g-1 compost. The predominant bacteria were characterized biochemically, followed by 16S rRNA gene sequencing. The isolated strains, both Gram-positive and Gram-negative groups belonged to the order Burkholderiales, Enterobacteriales, Actinobacteriales and Bacillales, which includes genera e.g. Staphylococcus, Serratia, Klebsiella, Enterobacter, Terribacillus, Lysinibacillus Kocuria, Microbacterium, Acidovorax and Comamonas. Genera like Kocuria, Microbacterium, Acidovorax, Comamonas and some new species of Bacillus were also identified for the first time from the compost made from agricultural byproducts. Conclusion The use of appropriate nitrogen amendments and bulking agents in composting resulted in good quality compost. The culture based strategy enabled us to isolate some novel bacterial isolates like Kocuria, Microbacterium, Acidovorax and Comamonas first time from agro-byproducts compost

  12. -Based Clathrate

    NASA Astrophysics Data System (ADS)

    Anno, Hiroaki; Shirataki, Ritsuko

    2014-06-01

    A polycrystalline silicon-based clathrate of nominal composition Ba8Al15Si31 was prepared by a combination of arc melting and spark plasma sintering. Its thermal stability in air and the effect on the surface of heat treatment in air, which are of practical importance for use of the material at elevated temperatures, were examined for different temperatures (873 K, 973 K, and 1073 K) and heating times (0-480 h). Thermogravimetry and differential thermal analysis in air in the range 300-1523 K indicated that Ba8Al15Si31 in the bulk form had relatively good thermal stability in air at high temperatures. X-ray diffraction measurements, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy revealed that a thin layer of oxide (probably a barium aluminate, BaAl2O4) was formed on the surface by heat treatment in air. The thickness of the oxide layer increased with increasing temperature and heating time. Growth of the oxide layer can be explained well in terms of a diffusion mechanism. The activation energy for oxidation was estimated to be approximately 201 kJ/mol, which is comparable with that for thermal oxidation of silicon. The chemical composition of the interior of the Ba8Al15Si31 was found to be stable to heat treatment in air.

  13. Foundation: Transforming data bases into knowledge bases

    NASA Technical Reports Server (NTRS)

    Purves, R. B.; Carnes, James R.; Cutts, Dannie E.

    1987-01-01

    One approach to transforming information stored in relational data bases into knowledge based representations and back again is described. This system, called Foundation, allows knowledge bases to take advantage of vast amounts of pre-existing data. A benefit of this approach is inspection, and even population, of data bases through an intelligent knowledge-based front-end.

  14. Michael hydratase alcohol dehydrogenase or just alcohol dehydrogenase?

    PubMed Central

    2014-01-01

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

  15. Microbial reduction of SO{sub 2} and NO{sub x} as a means of by- product recovery/disposal from regenerable processes for the desulfurization of flue gas. Technical progress report, June 11, 1992--September 11, 1992

    SciTech Connect

    Sublette, K.L.

    1992-12-31

    Based on the work described simultaneous SO{sub 2}/No{sub x} removal from flue gas based on direct contact of the gas with SRB and T. denitrificans co-cultures or cultures-in-series has been eliminated as a viable process concept at this time. The technical reasons are as follows: (1) NO inhibition of SO{sub 2} reduction by D. desulfuricans - Although the NO concentrations used in the experiments described above are somewhat higher than that found in a typical flue gas, it is quite possible that at lower NO concentrations (or partial pressures) the inhibiting effects will simply take longer to become apparent. (2) Nitrate suppression of NO removal - As noted previously, the cultivation of T. denitrificans in a microbial flue gas treatment system (either one or two stages) would require sulfide-limiting conditions. Therefore, the electron acceptor must be in excess, requiring nitrate in the T. denitrificans process culture. As shown in experiments described above, nitrate significantly suppresses the removal of NO from a feed gas making simultaneous SO{sub 2}/NO{sub x} removal impractical by microbial means. (3) O{sub 2} inhibition of SO{sub 2} and NO reduction - It has been demonstrated that D. desulfuricans working cultures are tolerant of up to 1.7% O{sub 2} in the feed gas. However, further increases in the O{sub 2} partial pressure in the feed gas resulted in O{sub 2} inhibition of SO{sub 2} reduction. These inhibiting levels of O{sub 2} are comparable to those concentrations found in flue gases (3). Therefore, in any process in which raw flue gas contacts a D. desulfuricans culture marginal stability at best can be expected.

  16. Microbial reduction of SO[sub 2] and NO[sub x] as a means of by- product recovery/disposal from regenerable processes for the desulfurization of flue gas

    SciTech Connect

    Sublette, K.L.

    1992-01-01

    Based on the work described simultaneous SO[sub 2]/No[sub x] removal from flue gas based on direct contact of the gas with SRB and T. denitrificans co-cultures or cultures-in-series has been eliminated as a viable process concept at this time. The technical reasons are as follows: (1) NO inhibition of SO[sub 2] reduction by D. desulfuricans - Although the NO concentrations used in the experiments described above are somewhat higher than that found in a typical flue gas, it is quite possible that at lower NO concentrations (or partial pressures) the inhibiting effects will simply take longer to become apparent. (2) Nitrate suppression of NO removal - As noted previously, the cultivation of T. denitrificans in a microbial flue gas treatment system (either one or two stages) would require sulfide-limiting conditions. Therefore, the electron acceptor must be in excess, requiring nitrate in the T. denitrificans process culture. As shown in experiments described above, nitrate significantly suppresses the removal of NO from a feed gas making simultaneous SO[sub 2]/NO[sub x] removal impractical by microbial means. (3) O[sub 2] inhibition of SO[sub 2] and NO reduction - It has been demonstrated that D. desulfuricans working cultures are tolerant of up to 1.7% O[sub 2] in the feed gas. However, further increases in the O[sub 2] partial pressure in the feed gas resulted in O[sub 2] inhibition of SO[sub 2] reduction. These inhibiting levels of O[sub 2] are comparable to those concentrations found in flue gases (3). Therefore, in any process in which raw flue gas contacts a D. desulfuricans culture marginal stability at best can be expected.

  17. Bacterial Diversity in Submarine Groundwater along the Coasts of the Yellow Sea

    PubMed Central

    Ye, Qi; Liu, Jianan; Du, Jinzhou; Zhang, Jing

    2016-01-01

    Submarine groundwater (SGD) is one of the most significant pathways for the exchange of groundwater and/or source of nutrients, metals and carbon to the ocean, subsequently cause deleterious impacts on the coastal ecosystems. Microorganisms have been recognized as the important participators in the biogeochemical processes in the SGD. In this study, by utilizing 16S rRNA-based Illumina Miseq sequencing technology, we investigated bacterial diversity and distribution in both fresh well water and brackish recirculated porewater along the coasts in the Yellow Sea. The results showed that Actinobacteria and Betaproteobacteria, especially Comamonas spp. and Limnohabitans spp. were dominated in fresh well samples. Distinct patterns of bacterial communities were found among the porewater samples due to different locations, for examples, Cyanbacteria was the most abundant in the porewater samples far from the algal bloomed areas. The analysis of correlation between representative bacterial taxonomic groups and the contexture environmental parameters showed that fresh well water and brackish porewater might provide different nutrients to the coastal waters. Potential key bacterial groups such as Comamonas spp. may be excellent candidates for the bioremediation of the natural pollutants in the SGD. Our comprehensive understanding of bacterial diversity in the SGD along the coasts of the Yellow Sea will create a basis for designing the effective clean-up approach in-situ, and provide valuable information for the coastal management. PMID:26779172

  18. Bacterial Diversity in Submarine Groundwater along the Coasts of the Yellow Sea.

    PubMed

    Ye, Qi; Liu, Jianan; Du, Jinzhou; Zhang, Jing

    2015-01-01

    Submarine groundwater (SGD) is one of the most significant pathways for the exchange of groundwater and/or source of nutrients, metals and carbon to the ocean, subsequently cause deleterious impacts on the coastal ecosystems. Microorganisms have been recognized as the important participators in the biogeochemical processes in the SGD. In this study, by utilizing 16S rRNA-based Illumina Miseq sequencing technology, we investigated bacterial diversity and distribution in both fresh well water and brackish recirculated porewater along the coasts in the Yellow Sea. The results showed that Actinobacteria and Betaproteobacteria, especially Comamonas spp. and Limnohabitans spp. were dominated in fresh well samples. Distinct patterns of bacterial communities were found among the porewater samples due to different locations, for examples, Cyanbacteria was the most abundant in the porewater samples far from the algal bloomed areas. The analysis of correlation between representative bacterial taxonomic groups and the contexture environmental parameters showed that fresh well water and brackish porewater might provide different nutrients to the coastal waters. Potential key bacterial groups such as Comamonas spp. may be excellent candidates for the bioremediation of the natural pollutants in the SGD. Our comprehensive understanding of bacterial diversity in the SGD along the coasts of the Yellow Sea will create a basis for designing the effective clean-up approach in-situ, and provide valuable information for the coastal management.

  19. Novel growth media for rearing larval horn flies, Haematobia irritans (Diptera: Muscidae).

    PubMed

    Perotti, M A; Lysyk, T J

    2003-01-01

    Experiments were conducted to develop an agar-based medium for rearing immature horn flies, Hematobia irritans (L.). Larval survival was determined on sterilized manure inoculated with pure and mixed cultures of Acinetobacter sp., Bacillus pumilus Meyer & Gottheil, Comamonas acidovorans den Dooren de Jong, Pseudomonas mendocina Palleroni, Flavobacterium sp. and Empedobacter breve (Holmes & Owen). Rearing larvae on mixed cultures enhanced pupal weight but not survival. Horn fly larvae failed to survive when reared on standard bacteriological media inoculated with pure and mixed cultures of Acinetobacter sp., P. mendocina, and C. acidovorans. Larvae completed development on a minimal medium supplemented with alfalfa, egg proteins, and vitamins. Medium with low alfalfa content (30 g alfalfa/500 ml minimal medium) had enhanced survival when supplemented with egg yolk protein and vitamins. Medium with high alfalfa content (130 g alfalfa/500 ml minimal medium) had enhanced survival when supplemented with whole egg protein and vitamins. Survival was also favored when media were inoculated with pure cultures of Acinetobacter or Acinetobacter mixed with either Pseudomonas or Comamonas. Individual plates could support larvae developing from up to 40 eggs, and survival was least variable when plates were inoculated with greater numbers of eggs. This rearing system shows promise as a means for conducting standardized bioassays on a meridic diet.

  20. (1) Microbial removal of SO sub 2 and NO sub x from flue gas; (2) Microbial by-product recovery from regenerable processes for the simultaneous removal of SO sub 2 and NO sub x from flue gas

    SciTech Connect

    Sublette, K.L. . Dept. of Chemical Engineering); Suciu, D. . Engineering Development Center)

    1990-02-01

    The objective of this project has been to investigate the reduction of SO{sub 2} to H{sub 2}S by Desulfovibrio desulfuricans in coculture with mixed fermentative heterotrophs and the reduction of NO to elemental nitrogen by Thiobacillus denitrificans. The ultimate goal has been the development of a viable process concept whereby a microbial process could impact on the problem of flue gas desulfurization and NO{sub x} removal. It was observed that molasses will support the reduction of SO{sub 2} to H{sub 2}S by working cultures of D. desulfuricans. However, the sulfur contained in the molasses resulted in H{sub 2}S production in excess of that expected based on the SO{sub 2} feed. We demonstrated the reduction of nitric oxide (NO) to elemental nitrogen (N{sub 2}) by Thiobacillus denitrificans. We also investigated the simultaneous removal of SO{sub 2} and NO from a gas by contact of the gas with either D. desulfuricans and T. denitrificans reactors-in-series or in co-culture. An economic evaluation of the microbial reduction of SO{sub 2} was performed comparing the microbial process to a conventional catalytic SO{sub 2} hydrogenation (with H{sub 2} generation from methane). Microbial SO{sub 2} reduction and conventional SO{sub 2} hydrogenation were estimated to have similar costs in terms of capital investment. However, annual operating costs for the microbial process were much higher than the conventional process, due primarily to the cost of raw materials. 52 refs., 38 figs., 20 tabs.

  1. Nickel-Resistant Bacteria from Anthropogenically Nickel-Polluted and Naturally Nickel-Percolated Ecosystems

    PubMed Central

    Stoppel, R.; Schlegel, H. G.

    1995-01-01

    DNA fragments harboring the nickel resistance determinants from bacteria isolated from anthropogenically polluted ecosystems in Europe and Zaire were compared with those harboring the nickel resistance determinants from bacteria isolated from naturally nickel-percolated soils from New Caledonia by DNA-DNA hybridization. The biotinylated DNA probes were derived from the previously described Alcaligenes eutrophus CH34, Alcaligenes xylosoxidans 31A, Alcaligenes denitrificans 4a-2, and Klebsiella oxytoca CCUG 15788 and four new nickel resistance-determining fragments cloned from strains isolated from soils under nickel-hyperaccumulating trees. Nine probes were hybridized with endonuclease-cleaved plasmid and total DNA samples from 56 nickel-resistant strains. Some of the New Caledonian strains were tentatively identified as Acinetobacter, Pseudomonas mendocina, Comamonas, Hafnia alvei, Burkholderia, Arthrobacter aurescens, and Arthrobacter ramosus strains. The DNA of most strains showed homologies to one or several of the following nickel resistance determinants: the cnr and ncc operons of the strains A. eutrophus CH34 and A. xylosoxidans 31A, respectively, the nre operon of strain 31A, and the nickel resistance determinants of K. oxytoca. On the basis of their hybridization reactions the nickel resistance determinants of the strains could be assigned to four groups: (i) cnr/ncc type, (ii) cnr/ncc/nre type, (iii) K. oxytoca type, and (iv) others. The majority of the strains were assigned to the known groups. Among the strains from Belgium and Zaire, exclusively the cnr/ncc and the cnr/ncc/nre types were found. Among the New Caledonian strains all four types were represented. Homologies to the nre operon were found only in combination with the cnr/ncc operon. The homologies to the cnr/ncc operon were the most abundant and were detected alone or together with homologies to the nre operon. Only the DNA of the strains isolated from soil in Scotland and the United States

  2. Team-Based Learning

    ERIC Educational Resources Information Center

    Michaelsen, Larry K.; Sweet, Michael

    2011-01-01

    Team-based learning (TBL), when properly implemented, includes many, if not all, of the common elements of evidence-based best practices. To explain this, a brief overview of TBL is presented. The authors examine the relationship between the best practices of evidence-based teaching and the principles that constitute team-based learning. (Contains…

  3. TARDEC Industrial Base Overview

    DTIC Science & Technology

    2010-11-30

    TARDEC Industrial Base Overview Randal Gaereminck, Associate Director, Industrial Base, Manufacturing, Logistics, & Value Engineering TARDEC...8-98) Prescribed by ANSI Std Z39-18 PURPOSE 2 To inform the conference attendees about TARDEC’s Industrial Base Mission and Capabilities AGENDA 3...Partnership • IBIT Policy Benefits • IBIT Mission • Industrial Base Engineering Support • Sustainment Engineering – Obsolescence • Industrial Base Engineering

  4. Volatile fatty acids influence on the structure of microbial communities producing PHAs

    PubMed Central

    Ciesielski, Slawomir; Przybylek, Grzegorz

    2014-01-01

    Polyhydroxyalkanoates (PHAs) can be produced by microorganisms and are a biodegradable alternative to fossil-fuel based plastics. Currently, the focus is on reducing production costs by exploring alternative substrates for PHAs production, and on producing copolymers which are less brittle than monomers. Accordingly, this study used a substrate consisting of wastewater from waste-glycerol fermentation, supplemented with different amounts of acetic and propionic acids. These substrates were used to feed mixed microbial communities enriched from activated sludge in a sequencing batch reactor. A reactor supplemented with 2 mL of acetic acid produced 227.8 mg/L of a homopolymer of hydroxybutyrate (3HB); 4 mL of acetic acid produced 279.8 mg/L 3HB; whereas 4 mL of propionic acid produced 673.0 mg/L of a copolymer of 3HB and 3HV (hydroxyvalerate). Ribosomal Intergenic Spacer Analysis (RISA) was used to show the differences between the communities created in the reactors. Thauera species predominated in biomass that produced 3HB; Paracoccus denitrificans in the biomass that produced 3HB-co-3HV. Because P. denitrificans produced the more desirable copolymer, it may be advantageous to promote its growth in PHAs-producing reactors by adding propionate. PMID:25242921

  5. Isolation and characterization of halophilic bacteria from Urmia Lake in Iran.

    PubMed

    Vahed, Sepideh Zununi; Forouhandeh, Haleh; Hassanzadeh, Salar; Klenk, Hans-Peter; Hejazi, Mohammad Amin; Hejazi, Mohammad Saeid

    2011-01-01

    Urmia Lake is one of the most permanent hypersaline lakes in the world which is threatened by hypersalinity and serious dryness. In spite of its importance no paper has been published regarding bacterial community of this lake. Accordingly, the present study aimed to investigate the halophilic bacteria in the aforementioned lake. In so doing, thirty seven strains were isolated on six different culture media. The isolated strains were characterized using phenotypic and genotypic methods. Growth of the strains occurred at 2535 degrees C, pH 6-9 and 7 to 20% (w/v) NaCl indicating that most of the isolates were moderately halophiles. Catalase, oxidase and urease activities were found to be positive for the majority of the isolates. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the isolated bacteria belonged to two major taxa: Gammaproteobacteria (92%, including Salicola [46%], Pseudomonas [13.5%], Marinobacter [ 11%], Idiomarina [11%], and Halomonas [8%]) and Firmicutes (8%, including Bacillus [5%] and Halobacillus [3%]). In addition, a novel bacterium whose 16S rRNA gene sequence showed almost 98% sequence identity with the taxonomically troubled DSM 3050T, Halovibrio denitrificans HGD 3T and Halospina denitrificans HGD 1-3T, each, was isolated. 16S rRNA gene similarity levels along with phenotypic characteristics suggest that some of the isolated strains could be regarded as potential type strain for novel species, on which further studies are recommended.

  6. Engineered Fv fragments as a tool for the one-step purification of integral multisubunit membrane protein complexes.

    PubMed

    Kleymann, G; Ostermeier, C; Ludwig, B; Skerra, A; Michel, H

    1995-02-01

    The preparation of pure and homogeneous membrane proteins or membrane protein complexes is time consuming, and the yields are frequently insufficient for structural studies. To circumvent these problems we established an indirect immunoaffinity chromatography method based on engineered Fv fragments. cDNAs encoding the variable domains of hybridoma-derived antibodies raised against various membrane proteins were cloned and expressed in Escherichia coli. The Fv fragments were engineered to serve as bifunctional adaptor molecules. The Fv fragment binds to the epitope of the membrane protein, while the Strep tag affinity peptide, which was fused to the carboxy-terminus of the VH chain, immobilizes the antigen-Fv complex on a streptavidin sepharose column. The usefulness of this technique is illustrated with membrane protein complexes from Paracoccus denitrificans, namely, the cytochrome c oxidase (EC 1.9.3.1), the ubiquinol:cytochrome c oxidoreductase (EC 1.10.2.2), and subcomplexes or individual subunits thereof. These membrane proteins were purified simply by combining the crude P. denitrificans membrane preparation with the E. coli periplasmic cell fraction containing the corresponding Fv fragment, followed by solubilization and streptavidin affinity chromatography. Pure and highly active membrane protein complexes were eluted in the Fv-bound form using diaminobiotin for mild competitive displacement of the Strep tag. The affinity column could thus be reused under continuous operation for several months. Five to 10 mg of membrane protein complexes could be obtained without any detectable impurities within five hours.

  7. Nitrate stimulation of indigenous nitrate-reducing, sulfide-oxidising bacterial community in wastewater anaerobic biofilms.

    PubMed

    Garcia-de-Lomas, Juan; Corzo, Alfonso; Carmen Portillo, M; Gonzalez, Juan M; Andrades, Jose A; Saiz-Jimenez, Cesáreo; Garcia-Robledo, Emilio

    2007-07-01

    The role of the nitrate-reducing, sulfide-oxidising bacteria (NR-SOB) in the nitrate-mediated inhibition of sulfide net production by anaerobic wastewater biofilms was analyzed in two experimental bioreactors, continuously fed with the primary effluent of a wastewater treatment plant, one used as control (BRC) and the other one supplemented with nitrate (BRN). This study integrated information from H(2)S and pH microelectrodes, RNA-based molecular techniques, and the time course of biofilm growth and bioreactors water phase. Biofilms were a net source of sulfide for the water phase (2.01 micromol S(2-)(tot)m(-2)s(-1)) in the absence of nitrate dosing. Nitrate addition effectively led to the cessation of sulfide release from biofilms despite which a low rate of net sulfate reduction activity (0.26 micromol S(2-)(tot)m(-2)s(-1)) persisted at a deep layer within the biofilm. Indigenous NR-SOB including Thiomicrospira denitrificans, Arcobacter sp., and Thiobacillus denitrificans were stimulated by nitrate addition resulting in the elimination of most sulfide from the biofilms. Active sulfate reducing bacteria (SRB) represented comparable fractions of total metabolically active bacteria in the libraries obtained from BRN and BRC. However, we detected changes in the taxonomic composition of the SRB community suggesting its adaptation to a higher level of NR-SOB activity in the presence of nitrate.

  8. Lunar base and Mars base design projects

    NASA Technical Reports Server (NTRS)

    Amos, J.; Campbell, J.; Hudson, C.; Kenny, E.; Markward, D.; Pham, C.; Wolf, C.

    1989-01-01

    The space design classes at the University of Texas at Austin undertook seven projects in support of the NASA/USRA advanced space design program during the 1988-89 year. A total of 51 students, including 5 graduate students, participated in the design efforts. Four projects were done within the Aerospace Engineering (ASE) design program and three within the Mechanical Engineering (ME) program. Both lunar base and Mars base design efforts were studied, and the specific projects were as follows: Lunar Crew Emergency Rescue Vehicle (ASE); Mars Logistics Lander Convertible to a Rocket Hopper (ME); A Robotically Constructed Production and Supply Base on Phobos (ASE); A Mars/Phobos Transportation System (ASE); Manned Base Design and Related Construction Issues for Mars/Phobos Mission (ME); and Health Care Needs for a Lunar Colony and Design of Permanent Medical Facility (ME).

  9. Logistics: Supply Based or Distribution Based?

    DTIC Science & Technology

    2007-04-01

    supply chain management, the need to adapt systems as conditions and capabilities change may not be clear or the root causes of problems may not be...logistics-system and supply - chain design and management positions. They need to become adept at integrating the full range of options available to...distribution-based and supply-based designs, the Army, in conjunction with its joint supply - chain partners, should seek optimal, balanced logistics system designs that it can adapt quickly to changing conditions.

  10. Microbial Community Dynamics and Activity Link to Indigo Production from Indole in Bioaugmented Activated Sludge Systems

    PubMed Central

    Deng, Jie; Deng, Ye; Van Nostrand, Joy D.; Wu, Liyou; He, Zhili; Qin, Yujia; Zhou, Jiti; Zhou, Jizhong

    2015-01-01

    Biosynthesis of the popular dyestuff indigo from indole has been comprehensively studied using pure cultures, but less has been done to characterize the indigo production by microbial communities. In our previous studies, a wild strain Comamonas sp. MQ was isolated from activated sludge and the recombinant Escherichia coli nagAc carrying the naphthalene dioxygenase gene (nag) from strain MQ was constructed, both of which were capable of producing indigo from indole. Herein, three activated sludge systems, G1 (non-augmented control), G2 (augmented with Comamonas sp. MQ), and G3 (augmented with recombinant E. coli nagAc), were constructed to investigate indigo production. After 132-day operation, G3 produced the highest yields of indigo (99.5 ± 3.0 mg/l), followed by G2 (27.3 ± 1.3 mg/l) and G1 (19.2 ± 1.2 mg/l). The microbial community dynamics and activities associated with indigo production were analyzed by Illumina Miseq sequencing of 16S rRNA gene amplicons. The inoculated strain MQ survived for at least 30 days, whereas E. coli nagAc was undetectable shortly after inoculation. Quantitative real-time PCR analysis suggested the abundance of naphthalene dioxygenase gene (nagAc) from both inoculated strains was strongly correlated with indigo yields in early stages (0–30 days) (P < 0.001) but not in later stages (30–132 days) (P > 0.10) of operation. Based on detrended correspondence analysis (DCA) and dissimilarity test results, the communities underwent a noticeable shift during the operation. Among the four major genera (> 1% on average), the commonly reported indigo-producing populations Comamonas and Pseudomonas showed no positive relationship with indigo yields (P > 0.05) based on Pearson correlation test, while Alcaligenes and Aquamicrobium, rarely reported for indigo production, were positively correlated with indigo yields (P < 0.05). This study should provide new insights into our understanding of indigo bio-production by microbial communities

  11. Carbon Based Nanotechnology: Review

    NASA Technical Reports Server (NTRS)

    Srivastava, Deepak; Saini, Subhash (Technical Monitor)

    1999-01-01

    This presentation reviews publicly available information related to carbon based nanotechnology. Topics covered include nanomechanics, carbon based electronics, nanodevice/materials applications, nanotube motors, nano-lithography and H2O storage in nanotubes.

  12. Centrality based Document Ranking

    DTIC Science & Technology

    2014-11-01

    approach. We model the documents to be ranked as nodes in a graph and place edges between documents based on their similarity. Given a query, we compute...similarity of the query with respect to every document in the graph . Based on these similarity values, documents are ranked for a given query...clinical documents using centrality based approach. We model the documents to be ranked as nodes in a graph and place edges between documents based on their

  13. Stolen Base Physics

    NASA Astrophysics Data System (ADS)

    Kagan, David

    2013-05-01

    Few plays in baseball are as consistently close and exciting as the stolen base. While there are several studies of sprinting,2-4 the art of base stealing is much more nuanced. This article describes the motion of the base-stealing runner using a very basic kinematic model. The model will be compared to some data from a Major League game. The predictions of the model show consistency with the skills needed for effective base stealing.

  14. Cooperative Knowledge Bases.

    DTIC Science & Technology

    1988-02-01

    intellegent knowledge bases. The present state of our system for concurrent evaluation of a knowledge base of logic clauses using static allocation...de Kleer, J., An assumption-based TMS, Artificial Intelligence, Vol. 28, No. 2, 1986. [Doyle 79) Doyle, J. A truth maintenance system, Artificial

  15. Stolen Base Physics

    ERIC Educational Resources Information Center

    Kagan, David

    2013-01-01

    Few plays in baseball are as consistently close and exciting as the stolen base. While there are several studies of sprinting, the art of base stealing is much more nuanced. This article describes the motion of the base-stealing runner using a very basic kinematic model. The model will be compared to some data from a Major League game. The…

  16. Community-based Education.

    ERIC Educational Resources Information Center

    Villani, Christine J.; Atkins, Douglas

    2000-01-01

    Based on work by Howard Gardner and James Comer, this article discusses the importance of creating and maintaining community-based relationships as part of community-based education. Students go beyond basic core academics and develop values and the freedom to uncover and resolve community problems or concerns. (MLH)

  17. Saturn base heating handbook

    NASA Technical Reports Server (NTRS)

    Mullen, C. R.; Bender, R. L.; Bevill, R. L.; Reardon, J.; Hartley, L.

    1972-01-01

    A handbook containing a summary of model and flight test base heating data from the S-1, S-1B, S-4, S-1C, and S-2 stages is presented. A review of the available prediction methods is included. Experimental data are provided to make the handbook a single source of Saturn base heating data which can be used for preliminary base heating design predictions of launch vehicles.

  18. Gasification-based biomass

    SciTech Connect

    None, None

    2009-01-18

    The gasification-based biomass section of the Renewable Energy Technology Characterizations describes the technical and economic status of this emerging renewable energy option for electricity supply.

  19. XML-BASED REPRESENTATION

    SciTech Connect

    R. KELSEY

    2001-02-01

    For focused applications with limited user and use application communities, XML can be the right choice for representation. It is easy to use, maintain, and extend and enjoys wide support in commercial and research sectors. When the knowledge and information to be represented is object-based and use of that knowledge and information is a high priority, then XML-based representation should be considered. This paper discusses some of the issues involved in using XML-based representation and presents an example application that successfully uses an XML-based representation.

  20. Soy-based polyols

    DOEpatents

    Suppes, Galen; Lozada, Zueica; Lubguban, Arnold

    2013-06-25

    The invention provides processes for preparing soy-based oligomeric polyols or substituted oligomeric polyols, as well as urethane bioelasteromers comprising the oligomeric polyols or substituted oligomeric polyols.

  1. Evaluation of the application potential of bentonites in phenanthrene bioremediation by characterizing the biofilm community.

    PubMed

    Huang, Yili; Zhang, Jing; Zhu, Lizhong

    2013-04-01

    Application of clay minerals in bioremediation has emerged as a new and promising research field. In this study, the application of calcinated bentonite (CB) and calcinated organobentonite (COB) in phenanthrene (Phe) bioremediation showed high Phe removal efficiency. Clone libraries based on 16S rRNA gene and scanning electronic microscopy showed that diverse taxa of bacteria formed biofilms on both COB and CB particles. The family Sphingomonadaceae was the major group and made up 18% and 23% of the COB and CB biofilm composition, respectively. All and 80% of dioxygenase genes from COB and CB biofilms were closely related to that of Sphingomonas sp., and others matched to that of Comamonas and Mycobacterium. The selective effect of COB on bacterial community was also evident. This study characterized for the first time the bacterial diversity of biofilm community and functional Phe degrading groups on bentonites particles, and provided useful information for future applications.

  2. Medical Knowledge Bases.

    ERIC Educational Resources Information Center

    Miller, Randolph A.; Giuse, Nunzia B.

    1991-01-01

    Few commonly available, successful computer-based tools exist in medical informatics. Faculty expertise can be included in computer-based medical information systems. Computers allow dynamic recombination of knowledge to answer questions unanswerable with print textbooks. Such systems can also create stronger ties between academic and clinical…

  3. Zero-Based Budgeting.

    ERIC Educational Resources Information Center

    Wichowski, Chester

    1979-01-01

    The zero-based budgeting approach is designed to achieve the greatest benefit with the fewest undesirable consequences. Seven basic steps make up the zero-based decision-making process: (1) identifying program goals, (2) classifying goals, (3) identifying resources, (4) reviewing consequences, (5) developing decision packages, (6) implementing a…

  4. Content-Based Instruction.

    ERIC Educational Resources Information Center

    CATESOL Journal, 1992

    1992-01-01

    This English-as-a-Second Language (ESL) journal periodical devotes entire issues to specific issues. The theme of this issue is "Content-Base Instruction." Articles include: "Syllabus Design in Content-Based Instruction" (David E. Eskey); "How Relevant Is Relevance?: An Examination of Student Needs, Interests, and…

  5. Content-Based Instruction

    ERIC Educational Resources Information Center

    DelliCarpini, M.; Alonso, O.

    2013-01-01

    DelliCarpini and Alonso's book "Content-Based Instruction" explores different approaches to teaching content-based instruction (CBI) in the English language classroom. They provide a comprehensive overview of how to teach CBI in an easy-to-follow guide that language teachers will find very practical for their own contexts. Topics…

  6. Red-based cumulus.

    PubMed

    Gedzelman, Stanley David

    2015-02-01

    Observations and model simulations of cumulus clouds whose bases are tinted red when the Sun is well above the horizon are presented. Conditions for seeing red bases include (1) a red underlying surface (which may consist of dust clouds, as from haboobs) with high albedo, (2) small fractional cloud cover when the Sun is far enough below the zenith for direct sunlight to illuminate much of the surface directly below and around cloud base, (3) optically thick clouds so that the bases are dark, and (4) clouds with bases that are near enough to the observer to appear high in the sky so that the admixture of scattered light from the intervening atmosphere is minimized.

  7. Base Flow Model Validation

    NASA Technical Reports Server (NTRS)

    Sinha, Neeraj; Brinckman, Kevin; Jansen, Bernard; Seiner, John

    2011-01-01

    A method was developed of obtaining propulsive base flow data in both hot and cold jet environments, at Mach numbers and altitude of relevance to NASA launcher designs. The base flow data was used to perform computational fluid dynamics (CFD) turbulence model assessments of base flow predictive capabilities in order to provide increased confidence in base thermal and pressure load predictions obtained from computational modeling efforts. Predictive CFD analyses were used in the design of the experiments, available propulsive models were used to reduce program costs and increase success, and a wind tunnel facility was used. The data obtained allowed assessment of CFD/turbulence models in a complex flow environment, working within a building-block procedure to validation, where cold, non-reacting test data was first used for validation, followed by more complex reacting base flow validation.

  8. Yeast Based Sensors

    NASA Astrophysics Data System (ADS)

    Shimomura-Shimizu, Mifumi; Karube, Isao

    Since the first microbial cell sensor was studied by Karube et al. in 1977, many types of yeast based sensors have been developed as analytical tools. Yeasts are known as facultative anaerobes. Facultative anaerobes can survive in both aerobic and anaerobic conditions. The yeast based sensor consisted of a DO electrode and an immobilized omnivorous yeast. In yeast based sensor development, many kinds of yeast have been employed by applying their characteristics to adapt to the analyte. For example, Trichosporon cutaneum was used to estimate organic pollution in industrial wastewater. Yeast based sensors are suitable for online control of biochemical processes and for environmental monitoring. In this review, principles and applications of yeast based sensors are summarized.

  9. Treatment of cosmetic effluent in different configurations of ceramic UF membrane based bioreactor: Toxicity evaluation of the untreated and treated wastewater using catfish (Heteropneustes fossilis).

    PubMed

    Banerjee, Priya; Dey, Tanmoy Kumar; Sarkar, Sandeep; Swarnakar, Snehasikta; Mukhopadhyay, Aniruddha; Ghosh, Sourja

    2016-03-01

    Extensive usage of pharmaceutical and personal care products (PPCPs) and their discharge through domestic sewage have been recently recognized as a new generation environmental concern which deserves more scientific attention over the classical environmental pollutants. The major issues of this type of effluent addressed in this study were its colour, triclosan and anionic surfactant (SDS) content. Samples of cosmetic effluent were collected from different beauty treatment salons and spas in and around Kolkata, India and treated in bioreactors containing a bacterial consortium isolated from activated sludge samples collected from a common effluent treatment plant. Members of the consortium were isolated and identified as Klebsiella sp., Pseudomonas sp., Salmonella sp. and Comamonas sp. The biotreated effluent was subjected to ultrafiltration (UF) involving indigenously prepared ceramic membranes in both side-stream and submerged mode. Analysis of the MBR treated effluent revealed 99.22%, 98.56% and 99.74% removal of colour, triclosan and surfactant respectively. Investigation of probable acute and chronic cyto-genotoxic potential of the untreated and treated effluents along with their possible participation in triggering oxidative stress was carried out with Heteropneustes fossilis (Bloch). Comet formation recorded in both liver and gill cells and micronucleus count in peripheral erythrocytes of individuals exposed to untreated effluent increased with duration of exposure and was significantly higher than those treated with UF permeates which in turn neared control levels. Results of this study revealed successful application of the isolated bacterial consortium in MBR process for efficient detoxification of cosmetic effluent thereby conferring the same suitable for discharge and/or reuse.

  10. Data base management study

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Data base management techniques and applicable equipment are described. Recommendations which will assist potential NASA data users in selecting and using appropriate data base management tools and techniques are presented. Classes of currently available data processing equipment ranging from basic terminals to large minicomputer systems were surveyed as they apply to the needs of potential SEASAT data users. Cost and capabilities projections for this equipment through 1985 were presented. A test of a typical data base management system was described, as well as the results of this test and recommendations to assist potential users in determining when such a system is appropriate for their needs. The representative system tested was UNIVAC's DMS 1100.

  11. Skull Base Anatomy.

    PubMed

    Patel, Chirag R; Fernandez-Miranda, Juan C; Wang, Wei-Hsin; Wang, Eric W

    2016-02-01

    The anatomy of the skull base is complex with multiple neurovascular structures in a small space. Understanding all of the intricate relationships begins with understanding the anatomy of the sphenoid bone. The cavernous sinus contains the carotid artery and some of its branches; cranial nerves III, IV, VI, and V1; and transmits venous blood from multiple sources. The anterior skull base extends to the frontal sinus and is important to understand for sinus surgery and sinonasal malignancies. The clivus protects the brainstem and posterior cranial fossa. A thorough appreciation of the anatomy of these various areas allows for endoscopic endonasal approaches to the skull base.

  12. Community-Based Care

    MedlinePlus

    ... providing important healthcare or personal care support. Adult Day Care Adult day care is a community-based option that has become ... support services in a group setting. Most adult day care centers are either in churches or community centers. ...

  13. Graphene-based composites.

    PubMed

    Huang, Xiao; Qi, Xiaoying; Boey, Freddy; Zhang, Hua

    2012-01-21

    Graphene has attracted tremendous research interest in recent years, owing to its exceptional properties. The scaled-up and reliable production of graphene derivatives, such as graphene oxide (GO) and reduced graphene oxide (rGO), offers a wide range of possibilities to synthesize graphene-based functional materials for various applications. This critical review presents and discusses the current development of graphene-based composites. After introduction of the synthesis methods for graphene and its derivatives as well as their properties, we focus on the description of various methods to synthesize graphene-based composites, especially those with functional polymers and inorganic nanostructures. Particular emphasis is placed on strategies for the optimization of composite properties. Lastly, the advantages of graphene-based composites in applications such as the Li-ion batteries, supercapacitors, fuel cells, photovoltaic devices, photocatalysis, as well as Raman enhancement are described (279 references).

  14. Evidence-based neurosurgery

    PubMed Central

    Esene, Ignatius N.; Baeesa, Saleh S.; Ammar, Ahmed

    2016-01-01

    Medical evidence is obtainable from approaches, which might be descriptive, analytic and integrative and ranked into levels of evidence, graded according to quality and summarized into strengths of recommendation. Sources of evidence range from expert opinions through well-randomized control trials to meta-analyses. The conscientious, explicit, and judicious use of current best evidence in making decisions related to the care of individual patients defines the concept of evidence-based neurosurgery (EBN). We reviewed reference books of clinical epidemiology, evidence-based practice and other previously related articles addressing principles of evidence-based practice in neurosurgery. Based on existing theories and models and our cumulative years of experience and expertise conducting research and promoting EBN, we have synthesized and presented a holistic overview of the concept of EBN. We have also underscored the importance of clinical research and its relationship to EBN. Useful electronic resources are provided. The concept of critical appraisal is introduced. PMID:27356649

  15. COMMUNITY BASED ENVIRONMENTAL PROTECTION

    EPA Science Inventory

    Community Based Environmental Protection intends to make environmental protection spring from the needs and values of the community of interest. Real community involvement in protecting the environment requires a process in which the environmental needs of communities and ecosyst...

  16. Benzimidazole Based Aerogel Materials

    NASA Technical Reports Server (NTRS)

    Rhine, Wendell E. (Inventor); Mihalcik, David (Inventor)

    2016-01-01

    The present invention provides aerogel materials based on imidazoles and polyimidazoles. The polyimidazole based aerogel materials can be thermally stable up to 500 C or more, and can be carbonized to produce a carbon aerogel having a char yield of 60% or more, specifically 70% or more. The present invention also provides methods of producing polyimidazole based aerogel materials by reacting at least one monomer in a suitable solvent to form a polybenzimidazole gel precursor solution, casting the polybenzimidazole gel precursor solution into a fiber reinforcement phase, allowing the at least one gel precursor in the precursor solution to transition into a gel material, and drying the gel materials to remove at least a portion of the solvent, to obtain an polybenzimidazole-based aerogel material.

  17. Transformation based endorsement systems

    NASA Technical Reports Server (NTRS)

    Sudkamp, Thomas

    1988-01-01

    Evidential reasoning techniques classically represent support for a hypothesis by a numeric value or an evidential interval. The combination of support is performed by an arithmetic rule which often requires restrictions to be placed on the set of possibilities. These assumptions usually require the hypotheses to be exhausitive and mutually exclusive. Endorsement based classification systems represent support for the alternatives symbolically rather than numerically. A framework for constructing endorsement systems is presented in which transformations are defined to generate and update the knowledge base. The interaction of the knowledge base and transformations produces a non-monotonic reasoning system. Two endorsement based reasoning systems are presented to demonstrate the flexibility of the transformational approach for reasoning with ambiguous and inconsistent information.

  18. Defining Empirically Based Practice.

    ERIC Educational Resources Information Center

    Siegel, Deborah H.

    1984-01-01

    Provides a definition of empirically based practice, both conceptually and operationally. Describes a study of how research and practice were integrated in the graduate social work program at the School of Social Service Administration, University of Chicago. (JAC)

  19. Microstereolithography for polymer-based based MEMS

    NASA Astrophysics Data System (ADS)

    Varadan, Vijay K.; Xie, Jining

    2003-07-01

    Microfabrication techniques such as bulk micromachining and surface micromachining currently employed to conceive MEMS are largely derived from the standard IC and microelectronics technology. Even though many MEMS devices with integrated electronics have been achieved by using the traditional micromachining techniques, some limitations have nevertheless to be underlined: 1) these techniques are very expensive and need specific installations as well as a cleanroom environment, 2) the materials that can be used up to now are restricted to silicon and metals, 3) the manufacture of 3D parts having curved surfaces or an important number of layers is not possible. Moreover, for some biological applications, the materials used for sensors must be compatible with human body and the actuators need to have high strain and displacement which the current silicon based MEMS do not provide. It is thus natural for the researchers to 'look' for alternative methods such as Microstereolithography (MSL) to make 3D sensors and actuators using polymeric based materials. For MSL techniques to be successful as their silicon counterparts, one has to come up with multifunctional polymers with electrical properties comparable to silicon. These multifunctional polymers should not only have a high sensing capability but also a high strain and actuation performance. A novel UV-curable polymer uniformly bonded with functionalized nanotubes was synthesized via a modified three-step in-situ polymerization. Purified multi-walled nanotubes, gained from the microwave chemical vapor deposition method, were functionalized by oxidation. The UV curable polymer was prepared from toluene diisocyanate (TDI), functionalized nanotubes, and 2-hydroxyethyl methacrylate (HEMA). The chemical bonds between -NCO groups of TDI and -OH, -COOH groups of functionalized nanotubes help for conceiving polymeric based MEMS devices. A cost effective fabrication techniques was presented using Micro Stereo Lithography and

  20. Information Based Numerical Practice.

    DTIC Science & Technology

    1987-02-01

    N I IIi I2 LA 1.6 liii I~JIIN MARYLAND COLLEGE PARK CAMPUS INSTITUTE FOR PHYSICAL SCIENCE AND TECHNOLOGY Technical Note S1-1059 INFORMATION BASED...K-0169 9. PERFORMING ORGANIZATION NMEU AMC ADDRESS 16. PROGRAM CELEMNT. PROJECT. TASK AREA & WORK UNIT NUNSERS, Institute for Physical Science and...BASED NUMERICAL PRACTICE I. Babuska Institute for Physical Science and Technology University of Maryland, College Park, MD 20740 a Partially supported by

  1. Layered nickel based superconductors

    SciTech Connect

    Ronning, Filip; Bauer, Eric D; Park, Tuson; Kurita, Nobuyuki; Klimczuk, T; Movshovich, R; Thompson, J D; Sefat, A S; Mandrus, D

    2009-01-01

    We review the properties of Ni-based superconductors which contain Ni{sub 2}X{sub 2} (X=As, P, Bi, Si, Ge, B) planes, a common structural element to the recently discovered FeAs superconductors. We also compare the properties ofthe Ni-and Fe-based systems from a perspective ofelectronic structure as well as structure-property relations.

  2. Agent Based Computing Machine

    DTIC Science & Technology

    2005-12-09

    coordinates as in cellular automata systems. But using biology as a model suggests that the most general systems must provide for partial, but constrained...17. SECURITY CLASSIFICATION OF 118. SECURITY CLASSIFICATION OF 19. SECURITY CLASSIFICATION OF 20. LIMITATION OF ABSTRA REPORT THIS PAGE ABSTRACT...system called an "agent based computing" machine (ABC Machine). The ABC Machine is motivated by cellular biochemistry and it is based upon a concept

  3. New formaldehyde base disinfectants.

    NASA Technical Reports Server (NTRS)

    Trujillo, R.; Lindell, K. F.

    1973-01-01

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

  4. LDEF materials data bases

    NASA Technical Reports Server (NTRS)

    Funk, Joan G.; Strickland, John W.; Davis, John M.

    1993-01-01

    The Long Duration Exposure Facility (LDEF) and the accompanying experiments were composed of and contained a wide variety of materials representing the largest collection of materials flown in low Earth orbit (LEO) and retrieved for ground based analysis to date. The results and implications of the mechanical, thermal, optical, and electrical data from these materials are the foundation on which future LEO space missions will be built. The LDEF Materials Special Investigation Group (MSIG) has been charged with establishing and developing data bases to document these materials and their performance to assure not only that the data are archived for future generations but also that the data are available to the spacecraft user community in an easily accessed, user-friendly form. This paper discusses the format and content of the three data bases developed or being developed to accomplish this task. The hardware and software requirements for each of these three data bases are discussed along with current availability of the data bases. This paper also serves as a user's guide to the MAPTIS LDEF Materials Data Base.

  5. Illumina MiSeq Sequencing Reveals Diverse Microbial Communities of Activated Sludge Systems Stimulated by Different Aromatics for Indigo Biosynthesis from Indole

    PubMed Central

    Zhang, Xuwang; Qu, Yuanyuan; Ma, Qiao; Zhang, Zhaojing; Li, Duanxing; Wang, Jingwei; Shen, Wenli; Shen, E; Zhou, Jiti

    2015-01-01

    Indole, as a typical N-heteroaromatic compound existed in coking wastewater, can be used for bio-indigo production. The microbial production of indigo from indole has been widely reported during the last decades using culture-dependent methods, but few studies have been carried out by microbial communities. Herein, three activated sludge systems stimulated by different aromatics, i.e. naphthalene plus indole (G1), phenol plus indole (G2) and indole only (G3), were constructed for indigo production from indole. During the operation, G1 produced the highest indigo yield in the early stage, but it switched to G3 in the late stage. Based on LC-MS analysis, indigo was the major product in G1 and G3, while the purple product 2-(7-oxo-1H-indol-6(7H)-ylidene) indolin-3-one was dominant in G2. Illumina MiSeq sequencing of 16S rRNA gene amplicons was applied to analyze the microbial community structure and composition. Detrended correspondence analysis (DCA) and dissimilarity tests showed that the overall community structures of three groups changed significantly during the operation (P<0.05). Nevertheless, the bacteria assigned to phylum Proteobacteria, family Comamonadaceae, and genera Diaphorobacter, Comamonas and Aquamicrobium were commonly shared dominant populations. Pearson correlations were calculated to discern the relationship between microbial communities and indigo yields. The typical indigo-producing populations Comamonas and Pseudomonas showed no positive correlations with indigo yields, while there emerged many other genera that exhibited positive relationships, such as Aquamicrobium, Truepera and Pusillimonas, which had not been reported for indigo production previously. The present study should provide new insights into indigo bio-production by microbial communities from indole. PMID:25928424

  6. [Evidence-based medicine].

    PubMed

    Saad, E D; Grunspun, H

    1996-01-01

    Evidence-based medicine has been described as a new approach to teaching and practicing clinical medicine. Although the search for evidence is an established practice among physicians, what is being proposed is the systematic gathering and critical interpretation of data, which can then be used in the appropriate context. The main objective is to provide better care for patients. This is accomplished by transforming clinical problems in specific questions to be answered by searching the literature for the levels of evidence favoring the possible interventions for one particular case. This has to be done in a systematic and conscientious fashion. Through its method, evidence-based medicine places less value on clinical experience, the study understanding of pathophysiology, and common sense; instead, it emphasizes observation, levels of evidence, and critical interpretation of original literature. In this manner, evidence-based medicine may be seen by the authoritarian physician as a threat. Other obstacles to the acceptance of the method include lack of time and lack of familiarity with computers. One important limitation of evidence-based medicine is the incomplete or contradictory evidence available in many areas of clinical medicine, or the so-called "grey zones". We outline the main aspects of evidence-based medicine, expecting a growing interest among brazilian physicians for this useful clinical tool.

  7. SAR based adaptive GMTI

    NASA Astrophysics Data System (ADS)

    Vu, Duc; Guo, Bin; Xu, Luzhou; Li, Jian

    2010-04-01

    We consider ground moving target indication (GMTI) and target velocity estimation based on multi-channel synthetic aperture radar (SAR) images. Via forming velocity versus cross-range images, we show that small moving targets can be detected even in the presence of strong stationary ground clutter. Moreover, the velocities of the moving targets can be estimated, and the misplaced moving targets can be placed back to their original locations based on the estimated velocities. Adaptive beamforming techniques, including Capon and generalizedlikelihood ratio test (GLRT), are used to form velocity versus cross-range images for each range bin of interest. The velocity estimation ambiguities caused by the multi-channel array geometry are analyzed. We also demonstrate the effectiveness of our approaches using the Air Force Research Laboratory (AFRL) publicly-released Gotcha SAR based GMTI data set.

  8. Model based manipulator control

    NASA Technical Reports Server (NTRS)

    Petrosky, Lyman J.; Oppenheim, Irving J.

    1989-01-01

    The feasibility of using model based control (MBC) for robotic manipulators was investigated. A double inverted pendulum system was constructed as the experimental system for a general study of dynamically stable manipulation. The original interest in dynamically stable systems was driven by the objective of high vertical reach (balancing), and the planning of inertially favorable trajectories for force and payload demands. The model-based control approach is described and the results of experimental tests are summarized. Results directly demonstrate that MBC can provide stable control at all speeds of operation and support operations requiring dynamic stability such as balancing. The application of MBC to systems with flexible links is also discussed.

  9. Protein based Block Copolymers

    PubMed Central

    Rabotyagova, Olena S.; Cebe, Peggy; Kaplan, David L.

    2011-01-01

    Advances in genetic engineering have led to the synthesis of protein-based block copolymers with control of chemistry and molecular weight, resulting in unique physical and biological properties. The benefits from incorporating peptide blocks into copolymer designs arise from the fundamental properties of proteins to adopt ordered conformations and to undergo self-assembly, providing control over structure formation at various length scales when compared to conventional block copolymers. This review covers the synthesis, structure, assembly, properties, and applications of protein-based block copolymers. PMID:21235251

  10. Lidar base specification

    USGS Publications Warehouse

    Heidemann, Hans Karl.

    2012-01-01

    Lidar is a fast evolving technology, and much has changed in the industry since the final draft of the “Lidar Base Specification Version 1.0” was written. Lidar data have improved in accuracy and spatial resolution, geospatial accuracy standards have been revised by the American Society for Photogrammetry and Remote Sensing (ASPRS), industry standard file formats have been expanded, additional applications for lidar have become accepted, and the need for interoperable data across collections has been realized. This revision to the “Lidar Base Specification Version 1.0” publication addresses those changes and provides continued guidance towards a nationally consistent lidar dataset.

  11. Intracranial dural based chondroma.

    PubMed

    Reinshagen, Clemens; Redjal, Navid; Sajed, Dipti P; Nahed, Brian V; Walcott, Brian P

    2016-03-01

    Intracranial chondromas are benign, slow-growing, cartilaginous tumors, which comprise only about 0.2% of all intracranial tumors. The majority of these lesions occur at the base of the skull, where they are thought to arise from residual embryonic chondrogenic cells along the basal synchondrosis. Very rarely, they may also originate from the convexity dura, falx cerebri, or the brain parenchyma. We present a patient with a dural based chondroma to highlight the technical considerations of surgical resection. The recent literature on intracranial chondromas regarding incidence, pathophysiologic origin, clinical symptoms, imaging, histopathology and prognosis is reviewed.

  12. Zero-Base Budgeting.

    ERIC Educational Resources Information Center

    Yagielski, John

    In outline form, this document presents basic information on the school district, the reasons the district considered zero-base budgeting (ZBB), the formation and membership of the advisory School Cost Analysis Team, the district's investigation of the ZBB concept, an overview of the ways the district used the ZBB process, the identification of…

  13. Problem-Based Learning

    ERIC Educational Resources Information Center

    Allen, Deborah E.; Donham, Richard S.; Bernhardt, Stephen A.

    2011-01-01

    In problem-based learning (PBL), students working in collaborative groups learn by resolving complex, realistic problems under the guidance of faculty. There is some evidence of PBL effectiveness in medical school settings where it began, and there are numerous accounts of PBL implementation in various undergraduate contexts, replete with…

  14. Orff-Based Improvisation.

    ERIC Educational Resources Information Center

    Thomas, Judith

    1980-01-01

    Described are improvisational activities based on the Orff-Schulwerk teaching technique which include: sound and movement; sound and movement plus visuals; interpretation of designs from nature, architecture, paintings, rotating rondo, singing hands, and moving from words to song. Pictures of children participating in these activities are…

  15. Team Based Work. Symposium.

    ERIC Educational Resources Information Center

    2002

    This document contains three papers from a symposium on team-based work in human resource development (HRD). "Toward Transformational Learning in Organizations: Effects of Model-II Governing Variables on Perceived Learning in Teams" (Blair K. Carruth) summarizes a study that indicated that, regardless of which Model-II variable (valid…

  16. Gasification at Navy Bases.

    DTIC Science & Technology

    1978-07-01

    Battalion Center at Port Hueneme, CA. The title of the contract was ’ Coal Gasification Feasibility Study.’ Coal gasification is recognized as a way...operated. A conceptual design study comparing coal gasification with central direct coal-fired boilers at five bases was performed.

  17. Polymer based tunneling sensor

    NASA Technical Reports Server (NTRS)

    Cui, Tianhong (Inventor); Wang, Jing (Inventor); Zhao, Yongjun (Inventor)

    2006-01-01

    A process for fabricating a polymer based circuit by the following steps. A mold of a design is formed through a lithography process. The design is transferred to a polymer substrate through a hot embossing process. A metal layer is then deposited over at least part of said design and at least one electrical lead is connected to said metal layer.

  18. SUPERCONDUCTING VANADIUM BASE ALLOY

    DOEpatents

    Cleary, H.J.

    1958-10-21

    A new vanadium-base alloy which possesses remarkable superconducting properties is presented. The alloy consists of approximately one atomic percent of palladium, the balance being vanadium. The alloy is stated to be useful in a cryotron in digital computer circuits.

  19. Lunar Base Sitting

    NASA Astrophysics Data System (ADS)

    Staehle, Robert L.; Burke, James D.; Snyder, Gerald C.; Dowling, Richard; Spudis, Paul D.

    1993-12-01

    Speculation with regard to a permanent lunar base has been with us since Robert Goddard was working on the first liquid-fueled rockets in the 1920's. With the infusion of data from the Apollo Moon flights, a once speculative area of space exploration has become an exciting possibility. A Moon base is not only a very real possibility, but is probably a critical element in the continuation of our piloted space program. This article, originally drafted by World Space Foundation volunteers in conjuction with various academic and research groups, examines some of the strategies involved in selecting an appropriate site for such a lunar base. Site selection involves a number of complex variables, including raw materials for possible rocket propellant generation, hot an cold cycles, view of the sky (for astronomical considerations, among others), geological makeup of the region, and more. This article summarizes the key base siting considerations and suggests some alternatives. Availability of specific resources, including energy and certain minerals, is critical to success.

  20. Lunar Base Sitting

    NASA Technical Reports Server (NTRS)

    Staehle, Robert L.; Burke, James D.; Snyder, Gerald C.; Dowling, Richard; Spudis, Paul D.

    1993-01-01

    Speculation with regard to a permanent lunar base has been with us since Robert Goddard was working on the first liquid-fueled rockets in the 1920's. With the infusion of data from the Apollo Moon flights, a once speculative area of space exploration has become an exciting possibility. A Moon base is not only a very real possibility, but is probably a critical element in the continuation of our piloted space program. This article, originally drafted by World Space Foundation volunteers in conjuction with various academic and research groups, examines some of the strategies involved in selecting an appropriate site for such a lunar base. Site selection involves a number of complex variables, including raw materials for possible rocket propellant generation, hot an cold cycles, view of the sky (for astronomical considerations, among others), geological makeup of the region, and more. This article summarizes the key base siting considerations and suggests some alternatives. Availability of specific resources, including energy and certain minerals, is critical to success.

  1. WATERSHED BASED SURVEY DESIGNS

    EPA Science Inventory

    The development of watershed-based design and assessment tools will help to serve the multiple goals for water quality monitoring required under the Clean Water Act, including assessment of regional condition to meet Section 305(b), identification of impaired water bodies or wate...

  2. Developing Mobile Based Instruction

    ERIC Educational Resources Information Center

    Martin, Florence; Pastore, Raymond; Snider, Jean

    2012-01-01

    This paper describes an instructional design class's experience developing instruction for the mobile web. The class was taught at a southeastern university in the United States in a master's level computer based instruction course. Two example projects are showcased and student reflections on design issues are highlighted. Additionally,…

  3. Aptamer-based nanobiosensors.

    PubMed

    Kim, Yeon Seok; Raston, Nurul Hanun Ahmad; Gu, Man Bock

    2016-02-15

    It has been more than two decades since aptamer and the systematic evolution of ligands by exponential enrichment (SELEX) method were discovered by Larry Gold and Andrew Ellington in 1990, respectively. Based on the various advantages of aptamers, they have become a potent rival of antibodies in therapeutics and bio-analysis. Especially, the recent advances in aptamer biosensor application are remarkable due to its intrinsic properties of aptamers as nucleic acids and target induced conformational changes, in addition to the introduction of graphene oxide-based easy and simple immobilization-free screening method even for dual aptamers. In addition, the incorporation of various nanomaterials such as metallic nanoparticles, carbon materials, and functional nanospheres in aptasensors has facilitated the improvement of analytical performance and commercial application of aptasensors. In this review, recent prominent reports on aptasensors utilizing nanomaterials were introduced to understand the principle of aptamer-based biosensors and provide an insight for new strategies of aptasensors and the application of various nanomaterials. The perspective on aptamer-based biosensors and diagnostics was also discussed in view of technology and market.

  4. School Based Health Centers

    ERIC Educational Resources Information Center

    Children's Aid Society, 2012

    2012-01-01

    School Based Health Centers (SBHC) are considered by experts as one of the most effective and efficient ways to provide preventive health care to children. Few programs are as successful in delivering health care to children at no cost to the patient, and where they are: in school. For many underserved children, The Children's Aid Society's…

  5. Shock wave data base

    NASA Astrophysics Data System (ADS)

    Levashov, P. R.; Fortov, V. E.; Khishchenko, K. V.; Lomov, I. N.; Lomonosov, I. V.

    1998-07-01

    The information on thermodynamic properties of matter under conditions of extremely high pressure and temperature is collected and treated. About 10000 experimental points are stored into ASCII files and converted into SQL format. Relational SQL data base is installed on server and graphical interface is elaborated. The information can be accessed via Internet with the help of Netscape Navigator 3.0 browser.

  6. Project-Based Science

    ERIC Educational Resources Information Center

    Krajcik, Joe

    2015-01-01

    Project-based science is an exciting way to teach science that aligns with the "Next Generation Science Standards" ("NGSS"). By focusing on core ideas along with practices and crosscutting concepts, classrooms become learning environments where teachers and students engage in science by designing and carrying out…

  7. Space based OTV servicing

    NASA Technical Reports Server (NTRS)

    Mcallister, J. G.

    1984-01-01

    Space based servicing of an orbit transfer vehicle (OTV) was previously outlined in sufficient detail to arrive at OTV and support system servicing requirements. Needed space station facilities and their functional requirements were identified. The impact of logistics and space serviceable design on the OTV design is detailed herein. RL10 derivative rocket engine inspection task times are enumerated.

  8. Zero-Base Budgeting.

    ERIC Educational Resources Information Center

    Harvey, L. James

    The concept of Zero-Base Budgeting (ZBB) is discussed in terms of its application, advantages, disadvantages, and implementation in an effective planning, management, and evaluation (PME) system. A ZBB system requires administrators to: review all programs and expenditures annually, set clear cut goals, and analyze all possible alternatives for…

  9. Achievement-Based Resourcing.

    ERIC Educational Resources Information Center

    Fletcher, Mike; And Others

    1992-01-01

    This collection of seven articles examines achievement-based resourcing (ABR), the concept that the funding of educational institutions should be linked to their success in promoting student achievement, with a focus on the application of ABR to postsecondary education in the United Kingdom. The articles include: (1) "Introduction" (Mick…

  10. Risk Assessment: Evidence Base

    NASA Technical Reports Server (NTRS)

    Johnson-Throop, Kathy A.

    2007-01-01

    Human systems PRA (Probabilistic Risk Assessment: a) Provides quantitative measures of probability, consequence, and uncertainty; and b) Communicates risk and informs decision-making. Human health risks rated highest in ISS PRA are based on 1997 assessment of clinical events in analog operational settings. Much work remains to analyze remaining human health risks identified in Bioastronautics Roadmap.

  11. Concept-Based Learning

    ERIC Educational Resources Information Center

    Schill, Bethany; Howell, Linda

    2011-01-01

    A major part of developing concept-based instruction is the use of an overarching idea to provide a conceptual lens through which students view the content of a particular subject. By using a conceptual lens to focus learning, students think at a much deeper level about the content and its facts (Erickson 2007). Therefore, the authors collaborated…

  12. Skull Base Tumors

    NASA Astrophysics Data System (ADS)

    Schulz-Ertner, Daniela

    In skull base tumors associated with a low radiosensitivity for conventional radiotherapy (RT), irradiation with proton or carbon ion beams facilitates a safe and accurate application of high tumor doses due to the favorable beam localization properties of these particle beams. Cranial nerves, the brain stem and normal brain tissue can at the same time be optimally spared.

  13. Landscape-based Indicators

    EPA Science Inventory

    The report is based on data and experience gained through the GLNPO-funded Great Lakes Coastal Wetland Consortium (GLCWC) and the EPA-STAR funded Great Lakes Ecological Indicators Project (GLEI). EPA-MED author Trebitz and other MED personnel were collaborators on the GLEI proje...

  14. Nanocarbon-based photovoltaics.

    PubMed

    Bernardi, Marco; Lohrman, Jessica; Kumar, Priyank V; Kirkeminde, Alec; Ferralis, Nicola; Grossman, Jeffrey C; Ren, Shenqiang

    2012-10-23

    Carbon materials are excellent candidates for photovoltaic solar cells: they are Earth-abundant, possess high optical absorption, and maintain superior thermal and photostability. Here we report on solar cells with active layers made solely of carbon nanomaterials that present the same advantages of conjugated polymer-based solar cells, namely, solution processable, potentially flexible, and chemically tunable, but with increased photostability and the possibility to revert photodegradation. The device active layer composition is optimized using ab initio density functional theory calculations to predict type-II band alignment and Schottky barrier formation. The best device fabricated is composed of PC(70)BM fullerene, semiconducting single-walled carbon nanotubes, and reduced graphene oxide. This active-layer composition achieves a power conversion efficiency of 1.3%-a record for solar cells based on carbon as the active material-and we calculate efficiency limits of up to 13% for the devices fabricated in this work, comparable to those predicted for polymer solar cells employing PCBM as the acceptor. There is great promise for improving carbon-based solar cells considering the novelty of this type of device, the high photostability, and the availability of a large number of carbon materials with yet untapped potential for photovoltaics. Our results indicate a new strategy for efficient carbon-based, solution-processable, thin film, photostable solar cells.

  15. A Mars base

    NASA Technical Reports Server (NTRS)

    Soule, Veronique

    1989-01-01

    This study was initiated to provide an approach to the development of a permanently manned Mars base. The objectives for a permanently manned Mars base are numerous. Primarily, human presence on Mars will allow utilization of new resources for the improvement of the quality of life on Earth, allowing for new discoveries in technologies, the solar system, and human physiology. Such a mission would also encourage interaction between different countries, increasing international cooperation and leading to a stronger unification of mankind. Surface studies of Mars, scientific experiments in the multiple fields, the research for new minerals, and natural resource production are more immediate goals of the Mars mission. Finally, in the future, colonization of Mars will ensure man's perpetual presence in the universe. Specific objectives of this study were: (1) to design a Mars habitat that minimizes the mass delivered to the Mars surface, provides long-stay capability for the base crew, and accommodates future expansion and modification; (2) to develop a scenario of the construction of a permanently manned Mars base; and (3) to incorporate new and envisioned technologies.

  16. Service-based Solutions.

    ERIC Educational Resources Information Center

    Cummings, Lynda; Winston, Michael

    1998-01-01

    Describes the Solutions model used at Shelley High School in Idaho which gives students the opportunity to gain practical experience while tackling community problems. This approach is built on the three fundamentals of an integrated curriculum, a problem-solving focus, and service-based learning. Sample problems include increasing certain trout…

  17. Protein Crystal Based Nanomaterials

    NASA Technical Reports Server (NTRS)

    Bell, Jeffrey A.; VanRoey, Patrick

    2001-01-01

    This is the final report on a NASA Grant. It concerns a description of work done, which includes: (1) Protein crystals cross-linked to form fibers; (2) Engineering of protein to favor crystallization; (3) Better knowledge-based potentials for protein-protein contacts; (4) Simulation of protein crystallization.

  18. Lidar base specification

    USGS Publications Warehouse

    Heidemann, Hans Karl.

    2012-01-01

    In late 2009, a $14.3 million allocation from the “American Recovery and Reinvestment Act” for new light detection and ranging (lidar) elevation data prompted the U.S. Geological Survey (USGS) National Geospatial Program (NGP) to develop a common base specification for all lidar data acquired for The National Map. Released as a draft in 2010 and formally published in 2012, the USGS–NGP “Lidar Base Specification Version 1.0” (now Lidar Base Specification) was quickly embraced as the foundation for numerous state, county, and foreign country lidar specifications. Prompted by a growing appreciation for the wide applicability and inherent value of lidar, a USGS-led consortium of Federal agencies commissioned a National Enhanced Elevation Assessment (NEEA) study in 2010 to quantify the costs and benefits of a national lidar program. A 2012 NEEA report documented a substantial return on such an investment, defined five Quality Levels (QL) for elevation data, and recommended an 8-year collection cycle of Quality Level 2 (QL2) lidar data as the optimum balance of benefit and affordability. In response to the study, the USGS–NGP established the 3D Elevation Program (3DEP) in 2013 as the interagency vehicle through which the NEEA recommendations could be realized. Lidar is a fast evolving technology, and much has changed in the industry since the final draft of the “Lidar Base Specification Version 1.0” was written. Lidar data have improved in accuracy and spatial resolution, geospatial accuracy standards have been revised by the American Society for Photogrammetry and Remote Sensing (ASPRS), industry standard file formats have been expanded, additional applications for lidar have become accepted, and the need for interoperable data across collections has been realized. This revision to the “Lidar Base Specification Version 1.0” publication addresses those changes and provides continued guidance towards a nationally consistent lidar dataset.

  19. UCG process data base

    SciTech Connect

    Thorsness, C.B.; Cena, R.J.

    1980-05-01

    Process modeling in underground coal gasification (UCG) systems is a useful tool. Often, however, the experimental data necessary to test proposed models and mechanisms is not readily available. To help overcome this problem we describe in this paper a UCG Data Base we are developing to assist in making detailed data from DOE-sponsored field programs easily available. In addition, the data in the current data base are used to summarize the results of the Hoe Creek I, II, and III experiments. A statistical look at these data indicate a general lack of correlation between process variables. A simple gas compositional model is presented and is shown to be consistent with much of the available field data.

  20. Carbon Nanotube based Nanotechnolgy

    NASA Astrophysics Data System (ADS)

    Meyyappan, M.

    2000-10-01

    Carbon nanotube(CNT) was discovered in the early 1990s and is an off-spring of C60(the fullerene or buckyball). CNT, depending on chirality and diameter, can be metallic or semiconductor and thus allows formation of metal-semiconductor and semiconductor-semiconductor junctions. CNT exhibits extraordinary electrical and mechanical properties and offers remarkable potential for revolutionary applications in electronics devices, computing and data storage technology, sensors, composites, storage of hydrogen or lithium for battery development, nanoelectromechanical systems(NEMS), and as tip in scanning probe microscopy(SPM) for imaging and nanolithography. Thus the CNT synthesis, characterization and applications touch upon all disciplines of science and engineering. A common growth method now is based on CVD though surface catalysis is key to synthesis, in contrast to many CVD applications common in microelectronics. A plasma based variation is gaining some attention. This talk will provide an overview of CNT properties, growth methods, applications, and research challenges and opportunities ahead.

  1. Cosinor-based rhythmometry

    PubMed Central

    2014-01-01

    A brief overview is provided of cosinor-based techniques for the analysis of time series in chronobiology. Conceived as a regression problem, the method is applicable to non-equidistant data, a major advantage. Another dividend is the feasibility of deriving confidence intervals for parameters of rhythmic components of known periods, readily drawn from the least squares procedure, stressing the importance of prior (external) information. Originally developed for the analysis of short and sparse data series, the extended cosinor has been further developed for the analysis of long time series, focusing both on rhythm detection and parameter estimation. Attention is given to the assumptions underlying the use of the cosinor and ways to determine whether they are satisfied. In particular, ways of dealing with non-stationary data are presented. Examples illustrate the use of the different cosinor-based methods, extending their application from the study of circadian rhythms to the mapping of broad time structures (chronomes). PMID:24725531

  2. Concrete lunar base investigation

    NASA Technical Reports Server (NTRS)

    Lin, T. D.; Senseney, Jonathan A.; Arp, Larry Dean; Lindbergh, Charles

    1989-01-01

    This paper presents results of structural analyses and a preliminary design of a precast, prestressed concrete lunar based subjected to one atmosphere internal pressure. The proposed infrastructure measures 120 ft in diameter and 72 ft in height, providing 33,000 sq ft of work area for scientific and industrial operations. Three loading conditions were considered in the design: (1) during construction; (2) under pressurization; and (3) during an air-leak scenario. A floating foundation, capable of rigid body rotation and translation as the lunar soil beneath it yields, was developed to support the infrastructure and to ensure the air-tightness of the system. Results reveal that it is feasible to use precast, prestressed concrete for construction of large lunar bases on the moon.

  3. Concrete lunar base investigation

    NASA Technical Reports Server (NTRS)

    Lin, T. D.; Senseny, Jonathan A.; Arp, Larry D.; Lindbergh, Charles

    1992-01-01

    This paper presents results of structural analyses and a preliminary design of a precast, prestressed concrete lunar base subjected to 1-atm internal pressure. The proposed infrastructure measures 120 ft in diameter and 72 ft in height, providing 33,000 sq ft of work area for scientific and industrial operations. Three loading conditions were considered in the design (1) during construction, (2) under pressurization, and (3) during an air-leak scenario. A floating foundation, capable of rigid body rotation and translation as the lunar soil beneath it yields, was developed to support the infrastructure and to ensure the airtightness of the system. Results reveal that it is feasible to use precast, prestressed concrete for construction of large lunar bases on the Moon.

  4. Space construction data base

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Construction of large systems in space is a technology requiring the development of construction methods to deploy, assemble, and fabricate the elements comprising such systems. A construction method is comprised of all essential functions and operations and related support equipment necessary to accomplish a specific construction task in a particular way. The data base objective is to provide to the designers of large space systems a compendium of the various space construction methods which could have application to their projects.

  5. Flock-based microfluidics.

    PubMed

    Hitzbleck, Martina; Lovchik, Robert D; Delamarche, Emmanuel

    2013-05-21

    Flock-based microfluidics are created by depositing hydrophilic microfibers on an adhesive-coated substrate using an electric field. This enables the fabrication of self-powered microfluidics from one or more different kinds of fibers that form 2D and 3D flowpaths, which can wick 40 microliters of liquid per square centimeter. With this approach, large areas of functional wicking materials can be produced at extremely low cost.

  6. Sea Basing Logistiek

    DTIC Science & Technology

    2007-11-01

    iets wat nu voor zware goederen niet mogeljk is met de middelen binnen de Nederlandse krijgsmachit. Nederland heeft bijvoorbeeld (nog) geen specifieke...weer gevechtsklaar zijn. Nederlandse troepen voeren de reconstitute fase in het algemeen uit in Nederland . [Kang&Gue] A special concern in sea based...besluit Nederland zelf in te grijpen. De Nederlandse vredesmissie bevindt zich nabij de kust. maar ver van de grens met buurlanden. De operatie kan niet

  7. Vehicle Based Vector Sensor

    DTIC Science & Technology

    2015-09-28

    300001 1 of 16 VEHICLE-BASED VECTOR SENSOR STATEMENT OF GOVERNMENT INTEREST [0001] The invention described herein may be manufactured and...unmanned underwater vehicle that can function as an acoustic vector sensor . (2) Description of the Prior Art [0004] It is known that a propagating...mechanics. An acoustic vector sensor measures the particle motion via an accelerometer and combines Attorney Docket No. 300001 2 of 16 the

  8. Pavement base drain evaluation

    NASA Astrophysics Data System (ADS)

    Hoffman, G. L.

    1981-06-01

    Portions of a highway drainage system design was revised. Essentially, the longitudinal drainage trench was moved closer to the pavement/shoulder joint, and the fine concrete sand layer was eliminated as a trench backfill material. The specified backfill material is a coarser crushed aggregate (pea gravel). An evaluation of the effects of these changes on pavement performance is given and the new pavement base drain system is compared to the older pipe foundation underdrain system at the same site.

  9. Granular loess classification based

    SciTech Connect

    Browzin, B.S.

    1985-05-01

    This paper discusses how loess might be identified by two index properties: the granulometric composition and the dry unit weight. These two indices are necessary but not always sufficient for identification of loess. On the basis of analyses of samples from three continents, it was concluded that the 0.01-0.5-mm fraction deserves the name loessial fraction. Based on the loessial fraction concept, a granulometric classification of loess is proposed. A triangular chart is used to classify loess.

  10. Refrigerator Based on Chemisorption

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.

    1987-01-01

    Reversible chemical reaction generates pressurized oxygen for cooling. Concept for cryogenic refrigerator based on chemical absorption of oxygen by praseodymium/cerium oxide (PCO) compound. Refrigerator produces cryogenic liquid for cooling infrared sensors. Also used for liquefying air and separating oxygen from nitrogen in air. In chemisorption refrigerator, PCO alternately absorbs and desorbs oxygen depending on whether cooled or heated. One pair of compressors accepts oxygen while others releases it. Compressed oxygen liquefied when precooked and expanded.

  11. Graphene-based biosensors

    NASA Astrophysics Data System (ADS)

    Lebedev, A. A.; Davydov, V. Yu.; Novikov, S. N.; Litvin, D. P.; Makarov, Yu. N.; Klimovich, V. B.; Samoilovich, M. P.

    2016-07-01

    Results of developing and testing graphene-based sensors capable of detecting protein molecules are presented. The biosensor operation was checked using an immunochemical system comprising fluorescein dye and monoclonal antifluorescein antibodies. The sensor detects fluorescein concentration on a level of 1-10 ng/mL and bovine serum albumin-fluorescein conjugate on a level of 1-5 ng/mL. The proposed device has good prospects for use for early diagnostics of various diseases.

  12. Projectile Base Flow Analysis

    DTIC Science & Technology

    2007-11-02

    S) AND ADDRESS(ES) DCW Industries, Inc. 5354 Palm Drive La Canada, CA 91011 8. PERFORMING ORGANIZATION...REPORT NUMBER DCW -38-R-05 9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS(ES) U. S. Army Research Office...Turbulence Modeling for CFD, Second Edition, DCW Industries, Inc., La Cañada, CA. Wilcox, D. C. (2001), “Projectile Base Flow Analysis,” DCW

  13. [Evidence based medicine].

    PubMed

    Cuestas, Eduardo

    2005-01-01

    Evidence based medicine is a systematic method employed to secure the best scientific available evidence when making clinical decisions. Several steps are taken in these process, describing a clinical scenario, formulating a specific clinical question, searching the literature for the pertinent studies, selecting the relevant articles using rules of evidence, understanding and calculating measures of effect, and finally incorporating the evidence and patients preferences in the clinical decision process.

  14. AIS Data Base Generation.

    DTIC Science & Technology

    1981-04-01

    the area of natura , ianguage understanding by computer come from the fields of Computational Linguistics and Artificial Intelligence (Al). In the last...blocks of the data base. Another interestino approach to automated database generation is the :m,? taiean ty the Heurist~c P’ogrimming Projec~t at...operating system. 22 OSI’s Orientation O)perling Systems’ approach to automated database generatio,.I i_- irrneo ~~ ciilpport c,’ riformatlon

  15. Space Based Communications

    NASA Technical Reports Server (NTRS)

    Simpson, James; Denson, Erik; Valencia, Lisa; Birr, Richard

    2003-01-01

    Current space lift launches on the Eastern and Western Range require extensive ground-based real-time tracking, communications and command/control systems. These are expensive to maintain and operate and cover only limited geographical areas. Future spaceports will require new technologies to provide greater launch and landing opportunities, support simultaneous missions, and offer enhanced decision support models and simulation capabilities. These ranges must also have lower costs and reduced complexity while continuing to provide unsurpassed safety to the public, flight crew, personnel, vehicles and facilities. Commercial and government space-based assets for tracking and communications offer many attractive possibilities to help achieve these goals. This paper describes two NASA proof-of-concept projects that seek-to exploit the advantages of a space-based range: Iridium Flight Modem and Space-Based Telemetry and Range Safety (STARS). Iridium Flight Modem uses the commercial satellite system Iridium for extremely low cost, low rate two-way communications and has been successfully tested on four aircraft flights. A sister project at Goddard Space Flight Center's (GSFC) Wallops Flight Facility (WFF) using the Globalstar system has been tested on one rocket. The basic Iridium Flight Modem system consists of a L1 carrier Coarse/Acquisition (C/A)-Code Global Positioning System (GPS) receiver, an on-board computer, and a standard commercial satellite modem and antennas. STARS uses the much higher data rate NASA owned Tracking and Data Relay Satellite System (TDRSS), a C/A-Code GPS receiver, an experimental low-power transceiver, custom built command and data handler processor, and digitized flight termination system (FTS) commands. STARS is scheduled to fly on an F-15 at Dryden Flight Research Center in the spring of 2003, with follow-on tests over the next several years.

  16. Example based lesion segmentation

    NASA Astrophysics Data System (ADS)

    Roy, Snehashis; He, Qing; Carass, Aaron; Jog, Amod; Cuzzocreo, Jennifer L.; Reich, Daniel S.; Prince, Jerry; Pham, Dzung

    2014-03-01

    Automatic and accurate detection of white matter lesions is a significant step toward understanding the progression of many diseases, like Alzheimer's disease or multiple sclerosis. Multi-modal MR images are often used to segment T2 white matter lesions that can represent regions of demyelination or ischemia. Some automated lesion segmentation methods describe the lesion intensities using generative models, and then classify the lesions with some combination of heuristics and cost minimization. In contrast, we propose a patch-based method, in which lesions are found using examples from an atlas containing multi-modal MR images and corresponding manual delineations of lesions. Patches from subject MR images are matched to patches from the atlas and lesion memberships are found based on patch similarity weights. We experiment on 43 subjects with MS, whose scans show various levels of lesion-load. We demonstrate significant improvement in Dice coefficient and total lesion volume compared to a state of the art model-based lesion segmentation method, indicating more accurate delineation of lesions.

  17. AFE base flow computations

    NASA Technical Reports Server (NTRS)

    Venkatapathy, Ethiraj; Prabhu, Dinesh K.; Palmer, Grant

    1991-01-01

    Hypersonic wake flows behind the Aeroassist Flight Experiment (AFE) geometry are analyzed using two Navier-Stokes flow solvers. Many of the AFE wake features observed in ballistic-range shadowgraphs are simulated using a simple, two-dimensional semicylinder geometry at moderate angles of attack. At free-stream conditions corresponding to a Hypersonic Free Flight Facility (HFFF) AFE experiment, the three-dimensional base flow for the AFE geometry is computed using an ideal-gas, Navier-Stokes solver. The computed results agree reasonably well with the shadowgraphs taken at the HFFF. An ideal-gas and a nonequilibrium Navier-Stokes solver have been coupled and applied to the complete flow around the AFE vehicle at the free-stream conditions corresponding to a nomial trajectory point. Limitations of the coupled ideal-gas and nonequilibrium solution are discussed. The nonequilibrium base flow solution is analyzed for the wake radiation and the radiation profiles along various lines of sight are compared. Finally, the wake unsteadiness is predicted using experimental correlations and the numerical solutions. An adaptive grid code, SAGE, has been used in all the simulations to enhance the solution accuracy. The grid adaptation is found to be necessary in obtaining base flow solutions with accurate flow features.

  18. Diet-induced developmental acceleration independent of TOR and insulin in C. elegans.

    PubMed

    MacNeil, Lesley T; Watson, Emma; Arda, H Efsun; Zhu, Lihua Julie; Walhout, Albertha J M

    2013-03-28

    Dietary composition has major effects on physiology. Here, we show that developmental rate, reproduction, and lifespan are altered in C. elegans fed Comamonas DA1877 relative to those fed a standard E. coli OP50 diet. We identify a set of genes that change in expression in response to this diet and use the promoter of one of these (acdh-1) as a dietary sensor. Remarkably, the effects on transcription and development occur even when Comamonas DA1877 is diluted with another diet, suggesting that Comamonas DA1877 generates a signal that is sensed by the nematode. Surprisingly, the developmental effect is independent from TOR and insulin signaling. Rather, Comamonas DA1877 affects cyclic gene expression during molting, likely through the nuclear hormone receptor NHR-23. Altogether, our findings indicate that different bacteria elicit various responses via distinct mechanisms, which has implications for diseases such as obesity and the interactions between the human microbiome and intestinal cells.

  19. RNA based evolutionary optimization

    NASA Astrophysics Data System (ADS)

    Schuster, Peter

    1993-12-01

    The notion of an RNA world has been introduced for a prebiotic scenario that is dominated by RNA molecules and their properties, in particular their capabilities to act as templates for reproduction and as catalysts for several cleavage and ligation reactions of polynucleotides and polypeptides. This notion is used here also for simple experimental assays which are well suited to study evolution in the test tube. In molecular evolution experiments fitness is determined in essence by the molecular structures of RNA molecules. Evidence is presented for adaptation to environment in cell-free media. RNA based molecular evolution experiments have led to interesting spin-offs in biotechnology, commonly called ‘applied molecular evolution’, which make use of Darwinian trial-and-error strategies in order to synthesize new pharmacological compounds and other advanced materials on a biological basis. Error-propagation in RNA replication leads to formation of mutant spectra called ‘quasispecies’. An increase in the error rate broadens the mutant spectrum. There exists a sharply defined threshold beyond which heredity breaks down and evolutionary adaptation becomes impossible. Almost all RNA viruses studied so far operate at conditions close to this error threshold. Quasispecies and error thresholds are important for an understanding of RNA virus evolution, and they may help to develop novel antiviral strategies. Evolution of RNA molecules can be studied and interpreted by considering secondary structures. The notion of sequence space introduces a distance between pairs of RNA sequences which is tantamount to counting the minimal number of point mutations required to convert the sequences into each other. The mean sensitivity of RNA secondary structures to mutation depends strongly on the base pairing alphabet: structures from sequences which contain only one base pair (GC or AU are much less stable against mutation than those derived from the natural (AUGC) sequences

  20. [Stewart's acid-base approach].

    PubMed

    Funk, Georg-Christian

    2007-01-01

    In addition to paCO(2), Stewart's acid base model takes into account the influence of albumin, inorganic phosphate, electrolytes and lactate on acid-base equilibrium. It allows a comprehensive and quantitative analysis of acid-base disorders. Particularly simultaneous and mixed metabolic acid-base disorders, which are common in critically ill patients, can be assessed. Stewart's approach is therefore a valuable tool in addition to the customary acid-base approach based on bicarbonate or base excess. However, some chemical aspects of Stewart's approach remain controversial.

  1. Polyolefin-Based Aerogels

    NASA Technical Reports Server (NTRS)

    Lee, Je Kyun; Gould, George

    2012-01-01

    An organic polybutadiene (PB) rubberbased aerogel insulation material was developed that will provide superior thermal insulation and inherent radiation protection, exhibiting the flexibility, resiliency, toughness, and durability typical of the parent polymer, yet with the low density and superior insulation properties associated with the aerogels. The rubbery behaviors of the PB rubber-based aerogels are able to overcome the weak and brittle nature of conventional inorganic and organic aerogel insulation materials. Additionally, with higher content of hydrogen in their structure, the PB rubber aerogels will also provide inherently better radiation protection than those of inorganic and carbon aerogels. Since PB rubber aerogels also exhibit good hydrophobicity due to their hydrocarbon molecular structure, they will provide better performance reliability and durability as well as simpler, more economic, and environmentally friendly production over the conventional silica or other inorganic-based aerogels, which require chemical treatment to make them hydrophobic. Inorganic aerogels such as silica aerogels demonstrate many unusual and useful properties. There are several strategies to overcoming the drawbacks associated with the weakness and brittleness of silica aerogels. Development of the flexible fiber-reinforced silica aerogel composite blanket has proven one promising approach, providing a conveniently fielded form factor that is relatively robust toward handling in industrial environments compared to silica aerogel monoliths. However, the flexible silica aerogel composites still have a brittle, dusty character that may be undesirable, or even intolerable, in certain applications. Although the cross-linked organic aerogels such as resorcinol-formaldehyde (RF), polyisocyanurate, and cellulose aerogels show very high impact strength, they are also very brittle with little elongation (i.e., less rubbery). Also, silica and carbon aerogels are less efficient

  2. Planktonic and biofilm-grown nitrogen-cycling bacteria exhibit different susceptibilities to copper nanoparticles.

    PubMed

    Reyes, Vincent C; Opot, Stephen O; Mahendra, Shaily

    2015-04-01

    Proper characterization of nanoparticle (NP) interactions with environmentally relevant bacteria under representative conditions is necessary to enable their sustainable manufacture, use, and disposal. Previous nanotoxicology research based on planktonic growth has not adequately explored biofilms, which serve as the predominant mode of bacterial growth in natural and engineered environments. Copper nanoparticle (Cu-NP) impacts on biofilms were compared with respective planktonic cultures of the ammonium-oxidizing Nitrosomonas europaea, nitrogen-fixing Azotobacter vinelandii, and denitrifying Paracoccus denitrificans using a suite of independent toxicity diagnostics. Median inhibitory concentration (IC50) values derived from adenosine triphosphate (ATP) for Cu-NPs were lower in N. europaea biofilms (19.6 ± 15.3 mg/L) than in planktonic cells (49.0 ± 8.0 mg/L). However, in absorbance-based growth assays, compared with unexposed controls, N. europaea growth rates in biofilms were twice as resilient to inhibition than those in planktonic cultures. Similarly, relative to unexposed controls, growth rates and yields of P. denitrificans in biofilms exposed to Cu-NPs were 40-fold to 50-fold less inhibited than those in planktonic cells. Physiological evaluation of ammonium oxidation and nitrate reduction suggested that biofilms were also less inhibited by Cu-NPs than planktonic cells. Furthermore, functional gene expression for ammonium oxidation (amoA) and nitrite reduction (nirK) showed lower inhibition by NPs in biofilms relative to planktonic-grown cells. These results suggest that biofilms mitigate NP impacts, and that nitrogen-cycling bacteria in wastewater, wetlands, and soils might be more resilient to NPs than planktonic-based assessments suggest.

  3. Internet Based Remote Operations

    NASA Technical Reports Server (NTRS)

    Chamberlain, James

    1999-01-01

    This is the Final Report for the Internet Based Remote Operations Contract, has performed payload operations research support tasks March 1999 through September 1999. These tasks support the GSD goal of developing a secure, inexpensive data, voice, and video mission communications capability between remote payload investigators and the NASA payload operations team in the International Space Station (ISS) era. AZTek has provided feedback from the NASA payload community by utilizing its extensive payload development and operations experience to test and evaluate remote payload operations systems. AZTek has focused on use of the "public Internet" and inexpensive, Commercial-off-the-shelf (COTS) Internet-based tools that would most benefit "small" (e.g., $2 Million or less) payloads and small developers without permanent remote operations facilities. Such projects have limited budgets to support installation and development of high-speed dedicated communications links and high-end, custom ground support equipment and software. The primary conclusions of the study are as follows: (1) The trend of using Internet technology for "live" collaborative applications such as telescience will continue. The GSD-developed data and voice capabilities continued to work well over the "public" Internet during this period. 2. Transmitting multiple voice streams from a voice-conferencing server to a client PC to be mixed and played on the PC is feasible. 3. There are two classes of voice vendors in the market: - Large traditional phone equipment vendors pursuing integration of PSTN with Internet, and Small Internet startups.The key to selecting a vendor will be to find a company sufficiently large and established to provide a base voice-conferencing software product line for the next several years.

  4. Characteristics Data Base

    SciTech Connect

    Lewis, E.D.; Moore, R.S. )

    1990-08-01

    The LWR Serial Numbers Database System (SNDB) contains detailed data about individual, historically discharged LWR spent fuel assemblies. This data includes the reactor where used, the year the assemblies were discharged, the pool where they are currently stored, assembly type, burnup, weight, enrichment, and an estimate of their radiological properties. This information is distributed on floppy disks to users in the nuclear industry to assist in planning for the permanent nuclear waste repository. This document describes the design and development of the SNDB. It provides a complete description of the file structures and an outline of the major code modules. It serves as a reference for a programmer maintaining the system, or for others interested in the technical detail of this database. This is the initial version of the SNDB. It contains historical data through December 31, 1987, obtained from the Energy Information Administration (EIA). EIA obtains the data from the utility companies via the RW-859 Survey Form. It evaluates and standardizes the data and distributes the resulting batch level database as a large file on magnetic tape. The Characteristics Data Base obtains this database for use in the LWR Quantities Data Base. Additionally, the CDB obtains the individual assembly level detail from EIA for use in the SNDB. While the Quantities Data Base retains only the level of detail necessary for its reporting, the SNDB does retain and use the batch level data to assist in the identification of a particular assembly serial number. We expect to update the SNDB on an annual basis, as new historical data becomes available.

  5. Sustainability Base Construction Update

    NASA Technical Reports Server (NTRS)

    Mewhinney, Michael

    2012-01-01

    Construction of the new Sustainability Base Collaborative support facility, expected to become the highest performing building in the federal government continues at NASA's Ames Research Center, Moffet Field, Calif. The new building is designed to achieve a platinum rating under the leadership in Energy and Environment Design (LEED) new construction standards for environmentally sustainable construction developed by the U. S. Green Building Council, Washington, D. C. When completed by the end of 2011, the $20.6 million building will feature near zero net energy consumption, use 90 percent less potable water than conventionally build buildings of equivalent size, and will result in reduced building maintenance costs.

  6. [Evidence-based physiotherapy].

    PubMed

    Bender, Tamás

    2013-12-01

    This article on physiotherapy presents some current evidence stating the strengths and weaknesses of the physiotherapeutic procedures. In the area of physiotherapy empirical data obtained during decades were overtaken by evidence from current studies. The author points out the great problem of physiotherapy, namely the heterogeneity of the applied parameters. Knowledge of current evidence may be very important and helpful for the physicians, but the author proposes, from the practical point of view, that physiotherapeutical procedures based on exprience and used for many years should not be entirely neglected. Nowadays physiotherapy plays an important role in the treament of locomotor diseases but its use is increasing in other fields of medicine, as well.

  7. Covering all the bases

    SciTech Connect

    Reimers, R.F.; Gross, M.P.

    1996-04-01

    The use of silent discharge plasma technology (SDPT) to treat volatile organic compounds (VOCs) at McClellan Air Force Base during a two-month test is described. SDPT was developed by Los Alamos National Laboratory and licensed to High Mesa Technologies. SDPT was used at McClellan to treat off-gases from air strippers, vapor-extraction systems, and incinerators at flow rates up to 10.4 scfm; destruction and removal efficiencies up to 99.4% were achieved. SDPT can also treat organic liquids by adding a packaged-bed reactor to the first stage system.

  8. NICKEL-BASE ALLOY

    DOEpatents

    Inouye, H.; Manly, W.D.; Roche, T.K.

    1960-01-19

    A nickel-base alloy was developed which is particularly useful for the containment of molten fluoride salts in reactors. The alloy is resistant to both salt corrosion and oxidation and may be used at temperatures as high as 1800 deg F. Basically, the alloy consists of 15 to 22 wt.% molybdenum, a small amount of carbon, and 6 to 8 wt.% chromium, the balance being nickel. Up to 4 wt.% of tungsten, tantalum, vanadium, or niobium may be added to strengthen the alloy.

  9. Base drive circuit

    DOEpatents

    Lange, Arnold C.

    1995-01-01

    An improved base drive circuit (10) having a level shifter (24) for providing bistable input signals to a pair of non-linear delays (30, 32). The non-linear delays (30, 32) provide gate control to a corresponding pair of field effect transistors (100, 106) through a corresponding pair of buffer components (88, 94). The non-linear delays (30, 32) provide delayed turn-on for each of the field effect transistors (100, 106) while an associated pair of transistors (72, 80) shunt the non-linear delays (30, 32) during turn-off of the associated field effect transistor (100, 106).

  10. Internet-Based Communication

    PubMed Central

    Gernsbacher, Morton Ann

    2015-01-01

    Google the question, “How is the Internet changing the way we communicate?,” and you will find no shortage of opinions, or fears, about the Internet altering the way we communicate. Although the Internet is not necessarily making communication briefer (neither is the Internet making communication less formal), the Internet is manifesting our preference for writing over speaking. I propose that our preference for communicating through Internet-based text derives from a fundamental feature of writing: In contrast to speech, which is most often synchronous, text is most often asynchronous. PMID:26330702

  11. Mars base buildup scenarios

    SciTech Connect

    Blacic, J.D.

    1985-01-01

    Two surface base build-up scenarios are presented in order to help visualize the mission and to serve as a basis for trade studies. In the first scenario, direct manned landings on the Martian surface occur early in the missions and scientific investigation is the main driver and rationale. In the second scenario, early development of an infrastructure to exploite the volatile resources of the Martian moons for economic purposes is emphasized. Scientific exploration of the surface is delayed at first, but once begun develops rapidly aided by the presence of a permanently manned orbital station.

  12. Alphavirus-Based Vaccines.

    PubMed

    Lundstrom, Kenneth

    2016-01-01

    Alphavirus vectors based on Semliki Forest virus, Sindbis virus, and Venezuelan equine encephalitis virus have been widely applied for vaccine development. Naked RNA replicons, recombinant viral particles, and layered DNA vectors have been subjected to immunization in preclinical animal models with antigens for viral targets and tumor antigens. Moreover, a limited number of clinical trials have been conducted in humans. Vaccination with alphavirus vectors has demonstrated efficient immune responses and has showed protection against challenges with lethal doses of virus and tumor cells, respectively. Moreover, vaccines have been developed against alphaviruses causing epidemics such as Chikungunya virus.

  13. Office-based anesthesia.

    PubMed

    Treasure, Trevor; Bennett, Jeffrey

    2007-02-01

    The practice of office-based oral and maxillofacial surgery is continuously expanding and involves the management of a diverse population in regards to the surgical procedures performed within the office and the age and medical health of the patients treated within the office. Comfort, cooperation, and hemodynamic stability are critical to satisfactorily accomplishing the surgical procedure. Various anesthetic techniques are used, including local anesthesia, anxiolysis, analgesia and sedation, and general anesthesia. The topic is vast and too extensive to be fully discussed in this article. The intent of this article is to provide a discussion of some fundamental concepts that can optimize anesthetic safety and care.

  14. Synchrotron based proton drivers

    SciTech Connect

    Weiren Chou

    2002-09-19

    Proton drivers are the proton sources that produce intense short proton bunches. They have a wide range of applications. This paper discusses the proton drivers based on high-intensity proton synchrotrons. It gives a review of the high-intensity proton sources over the world and a brief report on recent developments in this field in the U.S. high-energy physics (HEP) community. The Fermilab Proton Driver is used as a case study for a number of challenging technical design issues.

  15. TUNGSTEN BASE ALLOYS

    DOEpatents

    Schell, D.H.; Sheinberg, H.

    1959-12-15

    A high-density quaternary tungsten-base alloy having high mechanical strength and good machinability composed of about 2 wt.% Ni, 3 wt.% Cu, 5 wt.% Pb, and 90wt.% W is described. This alloy can be formed by the powder metallurgy technique of hot pressing in a graphite die without causing a reaction between charge and the die and without formation of a carbide case on the final compact, thereby enabling re-use of the graphite die. The alloy is formable at hot- pressing temperatures of from about 1200 to about 1350 deg C. In addition, there is little component shrinkage, thereby eliminating the necessity of subsequent extensive surface machining.

  16. Accelerator-based BNCT.

    PubMed

    Kreiner, A J; Baldo, M; Bergueiro, J R; Cartelli, D; Castell, W; Thatar Vento, V; Gomez Asoia, J; Mercuri, D; Padulo, J; Suarez Sandin, J C; Erhardt, J; Kesque, J M; Valda, A A; Debray, M E; Somacal, H R; Igarzabal, M; Minsky, D M; Herrera, M S; Capoulat, M E; Gonzalez, S J; del Grosso, M F; Gagetti, L; Suarez Anzorena, M; Gun, M; Carranza, O

    2014-06-01

    The activity in accelerator development for accelerator-based BNCT (AB-BNCT) both worldwide and in Argentina is described. Projects in Russia, UK, Italy, Japan, Israel, and Argentina to develop AB-BNCT around different types of accelerators are briefly presented. In particular, the present status and recent progress of the Argentine project will be reviewed. The topics will cover: intense ion sources, accelerator tubes, transport of intense beams, beam diagnostics, the (9)Be(d,n) reaction as a possible neutron source, Beam Shaping Assemblies (BSA), a treatment room, and treatment planning in realistic cases.

  17. Base drive circuit

    DOEpatents

    Lange, A.C.

    1995-04-04

    An improved base drive circuit having a level shifter for providing bistable input signals to a pair of non-linear delays. The non-linear delays provide gate control to a corresponding pair of field effect transistors through a corresponding pair of buffer components. The non-linear delays provide delayed turn-on for each of the field effect transistors while an associated pair of transistors shunt the non-linear delays during turn-off of the associated field effect transistor. 2 figures.

  18. Structure of the Toll/interleukin 1 receptor (TIR) domain of the immunosuppressive Brucella effector BtpA/Btp1/TcpB.

    PubMed

    Kaplan-Türköz, Burcu; Koelblen, Thomas; Felix, Christine; Candusso, Marie-Pierre; O'Callaghan, David; Vergunst, Annette C; Terradot, Laurent

    2013-11-01

    BtpA/Btp1/TcpB is a virulence factor produced by Brucella species that possesses a Toll interleukin-1 receptor (TIR) domain. Once delivered into the host cell, BtpA interacts with MyD88 to interfere with TLR signalling and modulates microtubule dynamics. Here the crystal structure of the BtpA TIR domain at 3.15 Å is presented. The structure shows a dimeric arrangement of a canonical TIR domain, similar to the Paracoccus denitrificans Tir protein but secured by a unique long N-terminal α-tail that packs against the TIR:TIR dimer. Structure-based mutations and multi-angle light scattering experiments characterized the BtpA dimer conformation in solution. The structure of BtpA will help with studies to understand the mechanisms involved in its interactions with MyD88 and with microtubules.

  19. Moon base reactor system

    NASA Technical Reports Server (NTRS)

    Chavez, H.; Flores, J.; Nguyen, M.; Carsen, K.

    1989-01-01

    The objective of our reactor design is to supply a lunar-based research facility with 20 MW(e). The fundamental layout of this lunar-based system includes the reactor, power conversion devices, and a radiator. The additional aim of this reactor is a longevity of 12 to 15 years. The reactor is a liquid metal fast breeder that has a breeding ratio very close to 1.0. The geometry of the core is cylindrical. The metallic fuel rods are of beryllium oxide enriched with varying degrees of uranium, with a beryllium core reflector. The liquid metal coolant chosen was natural lithium. After the liquid metal coolant leaves the reactor, it goes directly into the power conversion devices. The power conversion devices are Stirling engines. The heated coolant acts as a hot reservoir to the device. It then enters the radiator to be cooled and reenters the Stirling engine acting as a cold reservoir. The engines' operating fluid is helium, a highly conductive gas. These Stirling engines are hermetically sealed. Although natural lithium produces a lower breeding ratio, it does have a larger temperature range than sodium. It is also corrosive to steel. This is why the container material must be carefully chosen. One option is to use an expensive alloy of cerbium and zirconium. The radiator must be made of a highly conductive material whose melting point temperature is not exceeded in the reactor and whose structural strength can withstand meteor showers.

  20. DVD Based Electronic Pulser

    SciTech Connect

    Morris, Scott J.; Pratt, Rick M.; Hughes, Michael A.; Kouzes, Richard T.; Pitts, W. K.; Robinson, Eric E.

    2005-10-01

    This paper describes the design, construction, and testing of a DVD based electronic pulser system (DVDEPS). Such a device is used to generate pulse streams for simulation of both gamma and neutron detector systems. The DVDEPS reproduces a random pulse stream of a full HPGe spectrum as well as a digital pulse stream representing the output of a neutron multiplicity detector. The exchangeable DVD media contains over an hour of data for both detector systems and can contain an arbitrary gamma spectrum and neutron pulse stream. The data is written to the DVD using a desktop computer program from either actual or simulated spectra. The targeted use of the DVDEPS is authentication or validation of monitoring equipment for non-proliferation purposes, but it is also of general use whenever a complex data stream is required. The DVD based pulser combines the storage capacity and simplicity of DVD technology with commonly available electronic components to build a relatively inexpensive yet highly capable testing instrument.

  1. DVD Based Electronic Pulser

    SciTech Connect

    Morris, Scott J.; Pratt, Rick M.; Hughes, Michael A.; Kouzes, Richard T.; Pitts, W. K.; Robinson, Eric

    2006-08-01

    This article describes the design, construction, and testing of a digital versatile disc (DVD) based electronic pulser system (DVDEPS). Such a device is used to generate pulse streams for simulation of both gamma and neutron detector systems. The DVDEPS reproduces a random pulse stream of a full high purity germanium (HPGe) spectrum as well as a digital pulse stream representing the output of a neutron multiplicity detector. The exchangeable DVD media contains over an hour of data for both detector systems and can contain an arbitrary gamma spectrum and neutron pulse stream. The data is written to the DVD using a desktop computer program from either real or simulated spectra. The targeted use of the DVDEPS is authentication or validation of monitoring equipment for non-proliferation purposes, but it is also of general use in a variety of sitiuations. The DVD based pulser combines the storage capacity and simplicity of DVD technology with commonly available electronic components to build a relatively inexpensive yet highly capable testing instrument.

  2. Ground based infrared astronomy

    NASA Technical Reports Server (NTRS)

    Jennings, D. E.

    1988-01-01

    Infrared spectroscopic instrumentation has been developed for ground-based measurements of astrophysical objects in the intermediate infrared. A conventional Michelson interferometer is limited for astronomical applications in the intermediate infrared by quantum noise fluctuations in the radiation form the source and/or background incident on the detector, and the multiplex advantage is no longer available. One feasible approach to recovering the multiplex advantage is post-dispersion. The infrared signal after passing through telescope and interferometer, is dispersed by a low resolution grating spectrometer onto an array of detectors. The feasibility of the post-dispersion system has been demonstrated with observations of astrophysical objects in the 5 and 10 micrometer atmospheric windows from ground-based telescopes. During FY87/88 the post-disperser was used at the Kitt Peak 4-meter telescope and McMath telescope with facility Fourier transform spectrometers. Jupiter, Saturn, Mars, and Venus were observed. On Jupiter, the resolution at 12 micrometer was 0.01/cm, considerably higher than had been acheived previously. The spectrum contains Jovian ethane and acetylene emission. Construction was begun on the large cryogenic grating spectrometer.

  3. Model Based Definition

    NASA Technical Reports Server (NTRS)

    Rowe, Sidney E.

    2010-01-01

    In September 2007, the Engineering Directorate at the Marshall Space Flight Center (MSFC) created the Design System Focus Team (DSFT). MSFC was responsible for the in-house design and development of the Ares 1 Upper Stage and the Engineering Directorate was preparing to deploy a new electronic Configuration Management and Data Management System with the Design Data Management System (DDMS) based upon a Commercial Off The Shelf (COTS) Product Data Management (PDM) System. The DSFT was to establish standardized CAD practices and a new data life cycle for design data. Of special interest here, the design teams were to implement Model Based Definition (MBD) in support of the Upper Stage manufacturing contract. It is noted that this MBD does use partially dimensioned drawings for auxiliary information to the model. The design data lifecycle implemented several new release states to be used prior to formal release that allowed the models to move through a flow of progressive maturity. The DSFT identified some 17 Lessons Learned as outcomes of the standards development, pathfinder deployments and initial application to the Upper Stage design completion. Some of the high value examples are reviewed.

  4. Skyline based terrain matching

    NASA Technical Reports Server (NTRS)

    Page, Lance A.

    1990-01-01

    Skyline-based terrain matching, a new method for locating the vantage point of stereo camera or laser range-finding measurements on a global map previously prepared by satellite or aerial mapping is described. The orientation of the vantage is assumed known, but its translational parameters are determined by the algorithm. Skylines, or occluding contours, can be extracted from the sensory measurements taken by an autonomous vehicle. They can also be modeled from the global map, given a vantage estimate from which to start. The two sets of skylines, represented in cylindrical coordinates about either the true or the estimated vantage, are employed as 'features' or reference objects common to both sources of information. The terrain matching problem is formulated in terms of finding a translation between the respective representations of the skylines, by approximating the two sets of skylines as identical features (curves) on the actual terrain. The search for this translation is based on selecting the longest of the minimum-distance vectors between corresponding curves from the two sets of skylines. In successive iterations of the algorithm, the approximation that the two sets of curves are identical becomes more accurate, and the vantage estimate continues to improve. The algorithm was implemented and evaluated on a simulated terrain. Illustrations and examples are included.

  5. Model-Based Systems

    NASA Technical Reports Server (NTRS)

    Frisch, Harold P.

    2007-01-01

    Engineers, who design systems using text specification documents, focus their work upon the completed system to meet Performance, time and budget goals. Consistency and integrity is difficult to maintain within text documents for a single complex system and more difficult to maintain as several systems are combined into higher-level systems, are maintained over decades, and evolve technically and in performance through updates. This system design approach frequently results in major changes during the system integration and test phase, and in time and budget overruns. Engineers who build system specification documents within a model-based systems environment go a step further and aggregate all of the data. They interrelate all of the data to insure consistency and integrity. After the model is constructed, the various system specification documents are prepared, all from the same database. The consistency and integrity of the model is assured, therefore the consistency and integrity of the various specification documents is insured. This article attempts to define model-based systems relative to such an environment. The intent is to expose the complexity of the enabling problem by outlining what is needed, why it is needed and how needs are being addressed by international standards writing teams.

  6. Nanotechnology-Based Cosmeceuticals

    PubMed Central

    Lohani, Alka; Verma, Anurag; Joshi, Himanshi; Yadav, Niti; Karki, Neha

    2014-01-01

    Cosmeceuticals are the fastest growing segment of the personal care industry, and a number of topical cosmeceutical treatments for conditions such as photoaging, hyperpigmentation, wrinkles, and hair damage have come into widespread use. In the cosmeceutical arena nanotechnology has played an important role. Using new techniques to manipulate matter at an atomic or molecular level, they have been at the root of numerous innovations, opening up new perspectives for the future of cosmeceutical industry. Nanotechnology-based cosmeceuticals offer the advantage of diversity in products, and increased bioavailability of active ingredients and increase the aesthetic appeal of cosmeceutical products with prolonged effects. However increased use of nanotechnology in cosmeceuticals has raised concern about the possible penetration of nanoparticles through the skin and potential hazards to the human health. This review outlines the different nanoparticles used in various classes of cosmeceuticals, nanotechnology-based cosmeceutical products present in the market, and the potential risk caused by nanoparticles on exposure and recent regulatory steps taken to overcome them. PMID:24963412

  7. Droplet based microfluidics.

    PubMed

    Seemann, Ralf; Brinkmann, Martin; Pfohl, Thomas; Herminghaus, Stephan

    2012-01-01

    Droplet based microfluidics is a rapidly growing interdisciplinary field of research combining soft matter physics, biochemistry and microsystems engineering. Its applications range from fast analytical systems or the synthesis of advanced materials to protein crystallization and biological assays for living cells. Precise control of droplet volumes and reliable manipulation of individual droplets such as coalescence, mixing of their contents, and sorting in combination with fast analysis tools allow us to perform chemical reactions inside the droplets under defined conditions. In this paper, we will review available drop generation and manipulation techniques. The main focus of this review is not to be comprehensive and explain all techniques in great detail but to identify and shed light on similarities and underlying physical principles. Since geometry and wetting properties of the microfluidic channels are crucial factors for droplet generation, we also briefly describe typical device fabrication methods in droplet based microfluidics. Examples of applications and reaction schemes which rely on the discussed manipulation techniques are also presented, such as the fabrication of special materials and biophysical experiments.

  8. SPACE BASED INTERCEPTOR SCALING

    SciTech Connect

    G. CANAVAN

    2001-02-01

    Space Based Interceptor (SBI) have ranges that are adequate to address rogue ICBMs. They are not overly sensitive to 30-60 s delay times. Current technologies would support boost phase intercept with about 150 interceptors. Higher acceleration and velocity could reduce than number by about a factor of 3 at the cost of heavier and more expensive Kinetic Kill Vehicles (KKVs). 6g SBI would reduce optimal constellation costs by about 35%; 8g SBI would reduce them another 20%. Interceptor ranges fall rapidly with theater missile range. Constellations increase significantly for ranges under 3,000 km, even with advanced interceptor technology. For distributed launches, these estimates recover earlier strategic scalings, which demonstrate the improved absentee ratio for larger or multiple launch areas. Constellations increase with the number of missiles and the number of interceptors launched at each. The economic estimates above suggest that two SBI per missile with a modest midcourse underlay is appropriate. The SBI KKV technology would appear to be common for space- and surface-based boost phase systems, and could have synergisms with improved midcourse intercept and discrimination systems. While advanced technology could be helpful in reducing costs, particularly for short range theater missiles, current technology appears adequate for pressing rogue ICBM, accidental, and unauthorized launches.

  9. MS Based Metabonomics

    SciTech Connect

    Want, Elizabeth J.; Metz, Thomas O.

    2010-03-01

    Metabonomics is the latest and least mature of the systems biology triad, which also includes genomics and proteomics, and has its origins in the early orthomolecular medicine work pioneered by Linus Pauling and Arthur Robinson. It was defined by Nicholson and colleagues in 1999 as the quantitative measurement of perturbations in the metabolite complement of an integrated biological system in response to internal or external stimuli, and is often used today to describe many non-global types of metabolite analyses. Applications of metabonomics are extensive and include toxicology, nutrition, pharmaceutical research and development, physiological monitoring and disease diagnosis. For example, blood samples from millions of neonates are tested routinely by mass spectrometry (MS) as a diagnostic tool for inborn errors of metabolism. The metabonome encompasses a wide range of structurally diverse metabolites; therefore, no single analytical platform will be sufficient. Specialized sample preparation and detection techniques are required, and advances in NMR and MS technologies have led to enhanced metabonome coverage, which in turn demands improved data analysis approaches. The role of MS in metabonomics is still evolving as instrumentation and software becomes more sophisticated and as researchers realize the strengths and limitations of current technology. MS offers a wide dynamic range, high sensitivity, and reproducible, quantitative analysis. These attributes are essential for addressing the challenges of metabonomics, as the range of metabolite concentrations easily exceeds nine orders of magnitude in biofluids, and the diversity of molecular species ranges from simple amino and organic acids to lipids and complex carbohydrates. Additional challenges arise in generating a comprehensive metabolite profile, downstream data processing and analysis, and structural characterization of important metabolites. A typical workflow of MS-based metabonomics is shown in Figure

  10. 3. SOUTH SIDE. Edwards Air Force Base, South Base ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. SOUTH SIDE. - Edwards Air Force Base, South Base Sled Track, Firing & Control Blockhouse for 10,000-foot Track, South of Sled Track at midpoint of 20,000-foot track, Lancaster, Los Angeles County, CA

  11. Knowledge based question answering

    SciTech Connect

    Pazzani, M.J.; Engelman, C.

    1983-01-01

    The natural language database query system incorporated in the Knobs Interactive Planning System comprises a dictionary driven parser, APE-II, and script interpreter whch yield a conceptual dependency as a representation of the meaning of user input. A conceptualisation pattern matching production system then determines and executes a procedure for extracting the desired information from the database. In contrast to syntax driven q-a systems, e.g. those based on atn parsers, APE-II is driven bottom-up by expectations associated with word meanings. The goals of this approach include utilising similar representations for questions with similar meanings but widely varying surface structures, developing a powerful mechanism for the disambiguation of words with multiple meanings and the determination of pronoun referents, answering questions which require inferences to be understood, and interpreting ellipses and ungrammatical statements. The Knobs demonstration system is an experimental, expert system for air force mission planning applications. 16 refs.

  12. Liaison based assembly design

    SciTech Connect

    Ames, A.; Kholwadwala, D.; Wilson, R.H.

    1996-12-01

    Liaison Based Assembly Design extends the current information infrastructure to support design in terms of kinematic relationships between parts, or liaisons. These liaisons capture information regarding contact, degrees-of-freedom constraints and containment relationships between parts in an assembly. The project involved defining a useful collection of liaison representations, investigating their properties, and providing for maximum use of the data in downstream applications. We tested our ideas by implementing a prototype system involving extensions to Pro/Engineer and the Archimedes assembly planner. With an expanded product model, the design system is more able to capture design intent. When a product update is attempted, increased knowledge availability improves our ability to understand the effect of design changes. Manufacturing and analysis disciplines benefit from having liaison information available, so less time is wasted arguing over incomplete design specifications and our enterprise can be more completely integrated.

  13. DNA based molecular motors

    NASA Astrophysics Data System (ADS)

    Michaelis, Jens; Muschielok, Adam; Andrecka, Joanna; Kügel, Wolfgang; Moffitt, Jeffrey R.

    2009-12-01

    Most of the essential cellular processes such as polymerisation reactions, gene expression and regulation are governed by mechanical processes. Controlled mechanical investigations of these processes are therefore required in order to take our understanding of molecular biology to the next level. Single-molecule manipulation and force spectroscopy have over the last 15 years been developed into extremely powerful techniques. Applying these techniques to the investigation of proteins and DNA molecules has led to a mechanistic understanding of protein function on the level of single molecules. As examples for DNA based molecular machines we will describe single-molecule experiments on RNA polymerases as well as on the packaging of DNA into a viral capsid-a process that is driven by one of the most powerful molecular motors.

  14. Base isolation: Fresh insight

    SciTech Connect

    Shustov, V.

    1993-07-15

    The objective of the research is a further development of the engineering concept of seismic isolation. Neglecting the transient stage of seismic loading results in a widespread misjudgement: The force of resistance associated with velocity is mostly conceived as a source of damping vibrations, though it is an active force at the same time, during an earthquake type excitation. For very pliant systems such as base isolated structures with relatively low bearing stiffness and with artificially added heavy damping mechanism, the so called `damping`` force may occur even the main pushing force at an earthquake. Thus, one of the two basic pillars of the common seismic isolation philosophy, namely, the doctrine of usefulness and necessity of a strong damping mechanism, is turning out to be a self-deception, sometimes even jeopardizing the safety of structures and discrediting the very idea of seismic isolation. There is a way out: breaking with damping dependancy.

  15. Ferroelectrics based absorbing layers

    NASA Astrophysics Data System (ADS)

    Hao, Jianping; Sadaune, Véronique; Burgnies, Ludovic; Lippens, Didier

    2014-07-01

    We show that ferroelectrics-based periodic structure made of BaSrTiO3 (BST) cubes, arrayed onto a metal plate with a thin dielectric spacer film exhibit a dramatic enhancement of absorbance with value close to unity. The enhancement is found around the Mie magnetic resonance of the Ferroelectrics cubes with the backside metal layer stopping any transmitted waves. It also involves quasi-perfect impedance matching resulting in reflection suppression via simultaneous magnetic and electrical activities. In addition, it was shown numerically the existence of a periodicity optimum, which is explained from surface waves analysis along with trade-off between the resonance damping and the intrinsic loss of ferroelectrics cubes. An experimental verification in a hollow waveguide configuration with a good comparison with full-wave numerical modelling is at last reported by measuring the scattering parameters of single and dual BST cubes schemes pointing out coupling effects for densely packed structures.

  16. Information-based clustering

    PubMed Central

    Slonim, Noam; Atwal, Gurinder Singh; Tkačik, Gašper; Bialek, William

    2005-01-01

    In an age of increasingly large data sets, investigators in many different disciplines have turned to clustering as a tool for data analysis and exploration. Existing clustering methods, however, typically depend on several nontrivial assumptions about the structure of data. Here, we reformulate the clustering problem from an information theoretic perspective that avoids many of these assumptions. In particular, our formulation obviates the need for defining a cluster “prototype,” does not require an a priori similarity metric, is invariant to changes in the representation of the data, and naturally captures nonlinear relations. We apply this approach to different domains and find that it consistently produces clusters that are more coherent than those extracted by existing algorithms. Finally, our approach provides a way of clustering based on collective notions of similarity rather than the traditional pairwise measures. PMID:16352721

  17. Covariant mutually unbiased bases

    NASA Astrophysics Data System (ADS)

    Carmeli, Claudio; Schultz, Jussi; Toigo, Alessandro

    2016-06-01

    The connection between maximal sets of mutually unbiased bases (MUBs) in a prime-power dimensional Hilbert space and finite phase-space geometries is well known. In this article, we classify MUBs according to their degree of covariance with respect to the natural symmetries of a finite phase-space, which are the group of its affine symplectic transformations. We prove that there exist maximal sets of MUBs that are covariant with respect to the full group only in odd prime-power dimensional spaces, and in this case, their equivalence class is actually unique. Despite this limitation, we show that in dimension 2r covariance can still be achieved by restricting to proper subgroups of the symplectic group, that constitute the finite analogues of the oscillator group. For these subgroups, we explicitly construct the unitary operators yielding the covariance.

  18. Surface Plasmon Based Spectrometer

    NASA Astrophysics Data System (ADS)

    Wig, Andrew; Passian, Ali; Boudreaux, Philip; Ferrell, Tom

    2008-03-01

    A spectrometer that uses surface plasmon excitation in thin metal films to separate light into its component wavelengths is described. The use of surface plasmons as a dispersive medium sets this spectrometer apart from prism, grating, and interference based variants and allows for the miniaturization of this device. Theoretical and experimental results are presented for two different operation models. In the first case surface plasmon tunneling in the near field is used to provide transmission spectra of different broad band-pass, glass filters across the visible wavelength range with high stray-light rejection at low resolution as well as absorption spectra of chlorophyll extracted from a spinach leaf. The second model looks at the far field components of surface plasmon scattering.

  19. Race-based therapeutics.

    PubMed

    Yancy, Clyde W

    2008-08-01

    The issue of race in medicine is problematic. Race is not a physiologic grouping, and all persons of a given race do not necessarily share the same clinical phenotype or genetic substrate. Despite clear signals that certain risk factors and diseases vary as a function of race, translating those differences into race-based therapeutics has been awkward and has done little to change the natural history of cardiovascular disease as it affects special populations. Among the varied special populations, the African American population appears to have the most significant and adverse variances for cardiovascular disease as well as worrisome signals that drug responsiveness varies. Recent guideline statements have now acknowledged certain treatment options that are most appropriate for African Americans with cardiovascular disease, especially hypertension and heart failure. As more physiologic markers of disease and drug responsiveness become available, the need for racial designations in medicine may lessen, and therapies can be optimized for all patients without regard to race or ethnicity.

  20. Base Research Program

    SciTech Connect

    Everett Sondreal; John Hendrikson

    2009-03-31

    In June 2009, the Energy & Environmental Research Center (EERC) completed 11 years of research under the U.S. Department of Energy (DOE) Base Cooperative Agreement No. DE-FC26-98FT40320 funded through the Office of Fossil Energy (OFE) and administered at the National Energy Technology Laboratory (NETL). A wide range of diverse research activities were performed under annual program plans approved by NETL in seven major task areas: (1) resource characterization and waste management, (2) air quality assessment and control, (3) advanced power systems, (4) advanced fuel forms, (5) value-added coproducts, (6) advanced materials, and (7) strategic studies. This report summarizes results of the 67 research subtasks and an additional 50 strategic studies. Selected highlights in the executive summary illustrate the contribution of the research to the energy industry in areas not adequately addressed by the private sector alone. During the period of performance of the agreement, concerns have mounted over the impact of carbon emissions on climate change, and new programs have been initiated by DOE to ensure that fossil fuel resources along with renewable resources can continue to supply the nation's transportation fuel and electric power. The agreement has addressed DOE goals for reductions in CO{sub 2} emissions through efficiency, capture, and sequestration while expanding the supply and use of domestic energy resources for energy security. It has further contributed to goals for near-zero emissions from highly efficient coal-fired power plants; environmental control capabilities for SO{sub 2}, NO{sub x}, fine respirable particulate (PM{sub 2.5}), and mercury; alternative transportation fuels including liquid synfuels and hydrogen; and synergistic integration of fossil and renewable resources (e.g., wind-, biomass-, and coal-based electrical generation).

  1. Loyalty-based management.

    PubMed

    Reichheld, F F

    1993-01-01

    Despite a flurry of activities aimed at serving customers better, few companies have systematically revamped their operations with customer loyalty in mind. Instead, most have adopted improvement programs ad hoc, and paybacks haven't materialized. Building a highly loyal customer base must be integral to a company's basic business strategy. Loyalty leaders like MBNA credit cards are successful because they have designed their entire business systems around customer loyalty--a self-reinforcing system in which the company delivers superior value consistently and reinvents cash flows to find and keep high-quality customers and employees. The economic benefits of high customer loyalty are measurable. When a company consistently delivers superior value and wins customer loyalty, market share and revenues go up, and the cost of acquiring new customers goes down. The better economics mean the company can pay workers better, which sets off a whole chain of events. Increased pay boosts employee moral and commitment; as employees stay longer, their productivity goes up and training costs fall; employees' overall job satisfaction, combined with their experience, helps them serve customers better; and customers are then more inclined to stay loyal to the company. Finally, as the best customers and employees become part of the loyalty-based system, competitors are left to survive with less desirable customers and less talented employees. To compete on loyalty, a company must understand the relationships between customer retention and the other parts of the business--and be able to quantify the linkages between loyalty and profits. It involves rethinking and aligning four important aspects of the business: customers, product/service offering, employees, and measurement systems.

  2. Electrical percolation based biosensors.

    PubMed

    Bruck, Hugh Alan; Yang, Minghui; Kostov, Yordan; Rasooly, Avraham

    2013-10-01

    A new approach to label free biosensing has been developed based on the principle of "electrical percolation". In electrical percolation, long-range electrical connectivity is formed in randomly oriented and distributed systems of discrete elements. By applying this principle to biological interactions, it is possible to measure biological components both directly and electronically. The main element for electrical percolation biosensor is the biological semiconductor (BSC) which is a multi-layer 3-D carbon nanotube-antibody network. In the BSC, molecular interactions, such as binding of antigens to the antibodies, disrupt the network continuity causing increased resistance of the network. BSCs can be fabricated by immobilizing conducting elements, such as pre-functionalized single-walled carbon nanotubes (SWNTs)-antibody complex, directly onto a substrate, such as a Poly(methyl methacrylate) (PMMA) surface (also known as plexi-glass or Acrylic). BSCs have been demonstrated for direct (label-free) electronic measurements of antibody-antigen binding using SWNTs. If the concentration of the SWNT network is slightly above the electrical percolation threshold, then binding of a specific antigen to the pre-functionalized SWNT dramatically increases the electrical resistance due to changes in the tunneling between the SWNTs. Using anti-staphylococcal enterotoxin B (SEB) IgG as a "gate" and SEB as an "actuator", it was demonstrated that the BSC was able to detect SEB at concentrations of 1 ng/ml. Based on this concept, an automated configuration for BSCs is described here that enables real time continuous detection. The new BSC configuration may permit assembly of multiple sensors on the same chip to create "biological central processing units (CPUs)" with multiple biological elements, capable of processing and sorting out information on multiple analytes simultaneously.

  3. PROcess Based Diagnostics PROBE

    NASA Technical Reports Server (NTRS)

    Clune, T.; Schmidt, G.; Kuo, K.; Bauer, M.; Oloso, H.

    2013-01-01

    Many of the aspects of the climate system that are of the greatest interest (e.g., the sensitivity of the system to external forcings) are emergent properties that arise via the complex interplay between disparate processes. This is also true for climate models most diagnostics are not a function of an isolated portion of source code, but rather are affected by multiple components and procedures. Thus any model-observation mismatch is hard to attribute to any specific piece of code or imperfection in a specific model assumption. An alternative approach is to identify diagnostics that are more closely tied to specific processes -- implying that if a mismatch is found, it should be much easier to identify and address specific algorithmic choices that will improve the simulation. However, this approach requires looking at model output and observational data in a more sophisticated way than the more traditional production of monthly or annual mean quantities. The data must instead be filtered in time and space for examples of the specific process being targeted.We are developing a data analysis environment called PROcess-Based Explorer (PROBE) that seeks to enable efficient and systematic computation of process-based diagnostics on very large sets of data. In this environment, investigators can define arbitrarily complex filters and then seamlessly perform computations in parallel on the filtered output from their model. The same analysis can be performed on additional related data sets (e.g., reanalyses) thereby enabling routine comparisons between model and observational data. PROBE also incorporates workflow technology to automatically update computed diagnostics for subsequent executions of a model. In this presentation, we will discuss the design and current status of PROBE as well as share results from some preliminary use cases.

  4. Problem-Based Learning in Web-Based Science Classroom.

    ERIC Educational Resources Information Center

    Kim, Heeyoung; Chung, Ji-Sook; Kim, Younghoon

    The purpose of this paper is to discuss how general problem-based learning (PBL) models and social-constructivist perspectives are applied to the design and development of a Web-based science program, which emphasizes inquiry-based learning for fifth grade students. The paper also deals with the general features and learning process of a Web-based…

  5. Performance-Based Funding Brief

    ERIC Educational Resources Information Center

    Washington Higher Education Coordinating Board, 2011

    2011-01-01

    A number of states have made progress in implementing performance-based funding (PFB) and accountability. This policy brief summarizes main features of performance-based funding systems in three states: Tennessee, Ohio, and Indiana. The brief also identifies key issues that states considering performance-based funding must address, as well as…

  6. Neighborhood-Based Family Support.

    ERIC Educational Resources Information Center

    Downs, Susan Whitelaw

    This report provides an overview of neighborhood-based family-support programs and describes the development of the family-support movement. It includes sections on the definition of neighborhood-based family-support programs, the principles and theories on which they are based, a discussion of the problems they are designed to address, a…

  7. Mentalization-Based Treatment

    PubMed Central

    Bateman, Anthony; Fonagy, Peter

    2013-01-01

    The concept of mentalizing has captured the interest and imagination of an astonishing range of people—from psychoanalysts to neuroscientists, from child development researchers to geneticists, from existential philosophers to phenomenologists—all of whom seem to have found it useful. According to the Thompson Reuter maintained Web of Science, the use of the term in titles and abstracts of scientific papers increased from 10 to 2,750 between 1991 and 2011. Clinicians in particular have enthusiastically embraced the idea, and have put it to innovative use in their practices. Mentalization-based treatment (MBT)—making mentalizing a core focus of therapy—was initially developed for the treatment of borderline personality disorder (BPD) in routine clinical services delivered in group and individual modalities. Therapy with mentalizing as a central component is currently being developed for treatment of numerous groups, including people with antisocial personality disorder, substance abuse, eating disorders, and at-risk mothers with infants and children (A. Bateman & Fonagy, 2011). It is also being used with families and adolescents, in schools, and in managing social groups (Asen & Fonagy, 2011; Fonagy et al., 2009; Twemlow, Fonagy, & Sacco, 2005a, 2005b). In this article, we focus on MBT in the treatment of BPD. PMID:26157198

  8. Microsphere based saliva diagnostics

    NASA Astrophysics Data System (ADS)

    Rissin, David M.; DiCesare, Christopher; Hayman, Ryan B.; Blicharz, Timothy M.; Walt, David R.

    2005-11-01

    Saliva presents a minimally invasive alternative medium to blood for performing diagnostics1. Microsphere sensors for ions, small organic molecules, and proteins are currently being developed and optical microarrays containing thousands of these sensors will be used for simultaneous multi-analyte analysis. The fiber bundle platform in use is 1mm in diameter and contains approximately 50,000 individually addressable 3.1μm fibers, each with an etched well capable of housing a single 3.1μm microsphere sensor. Micron-sized bead-based chemistries are produced in house, followed by deposition onto a fiber-optic bundle platform, allowing for multiplexed analysis. The ultimate goal is to develop a universal diagnostic system using saliva as the diagnostic medium. This platform will permit multiplexed analysis of a sample by integrating microfluidics with the optical arrays loaded with sensors capable of detecting relevant biomarkers associated with a wide range of disease states. Disease states that are currently under investigation include end stage renal disease (ESRD) and Sjoegrens Syndrome (SS).

  9. Alphavirus-Based Vaccines

    PubMed Central

    Lundstrom, Kenneth

    2014-01-01

    Alphavirus vectors have demonstrated high levels of transient heterologous gene expression both in vitro and in vivo and, therefore, possess attractive features for vaccine development. The most commonly used delivery vectors are based on three single-stranded encapsulated alphaviruses, namely Semliki Forest virus, Sindbis virus and Venezuelan equine encephalitis virus. Alphavirus vectors have been applied as replication-deficient recombinant viral particles and, more recently, as replication-proficient particles. Moreover, in vitro transcribed RNA, as well as layered DNA vectors have been applied for immunization. A large number of highly immunogenic viral structural proteins expressed from alphavirus vectors have elicited strong neutralizing antibody responses in multispecies animal models. Furthermore, immunization studies have demonstrated robust protection against challenges with lethal doses of virus in rodents and primates. Similarly, vaccination with alphavirus vectors expressing tumor antigens resulted in prophylactic protection against challenges with tumor-inducing cancerous cells. As certain alphaviruses, such as Chikungunya virus, have been associated with epidemics in animals and humans, attention has also been paid to the development of vaccines against alphaviruses themselves. Recent progress in alphavirus vector development and vaccine technology has allowed conducting clinical trials in humans. PMID:24937089

  10. Constraint-based scheduling

    NASA Technical Reports Server (NTRS)

    Zweben, Monte

    1991-01-01

    The GERRY scheduling system developed by NASA Ames with assistance from the Lockheed Space Operations Company, and the Lockheed Artificial Intelligence Center, uses a method called constraint based iterative repair. Using this technique, one encodes both hard rules and preference criteria into data structures called constraints. GERRY repeatedly attempts to improve schedules by seeking repairs for violated constraints. The system provides a general scheduling framework which is being tested on two NASA applications. The larger of the two is the Space Shuttle Ground Processing problem which entails the scheduling of all inspection, repair, and maintenance tasks required to prepare the orbiter for flight. The other application involves power allocations for the NASA Ames wind tunnels. Here the system will be used to schedule wind tunnel tests with the goal of minimizing power costs. In this paper, we describe the GERRY system and its applications to the Space Shuttle problem. We also speculate as to how the system would be used for manufacturing, transportation, and military problems.

  11. Constraint-based scheduling

    NASA Technical Reports Server (NTRS)

    Zweben, Monte

    1991-01-01

    The GERRY scheduling system developed by NASA Ames with assistance from the Lockheed Space Operations Company, and the Lockheed Artificial Intelligence Center, uses a method called constraint-based iterative repair. Using this technique, one encodes both hard rules and preference criteria into data structures called constraints. GERRY repeatedly attempts to improve schedules by seeking repairs for violated constraints. The system provides a general scheduling framework which is being tested on two NASA applications. The larger of the two is the Space Shuttle Ground Processing problem which entails the scheduling of all the inspection, repair, and maintenance tasks required to prepare the orbiter for flight. The other application involves power allocation for the NASA Ames wind tunnels. Here the system will be used to schedule wind tunnel tests with the goal of minimizing power costs. In this paper, we describe the GERRY system and its application to the Space Shuttle problem. We also speculate as to how the system would be used for manufacturing, transportation, and military problems.

  12. Lunar base construction requirements

    NASA Technical Reports Server (NTRS)

    Jolly, Steve; Helleckson, Brent

    1990-01-01

    The following viewgraph presentation is a review of the Lunar Base Constructibility Study carried out in the spring and summer of 1990. The objective of the study was to develop a method for evaluating the constructibility of Phase A proposals to build facilities on orbit or on extraterrestrial surfaces. Space construction was broadly defined as all forms of assembly, disassembly, connection, disconnection, deployment, stowage, excavation, emplacement, activation, test, transportation, etc., required to create facilities in orbit and on the surfaces of other celestial bodies. It was discovered that decisions made in the face of stated and unstated assumptions early in the design process (commonly called Phase A) can lock in non-optimal construction methods. Often, in order to construct the design, alterations must be made to the design during much later phases of the project. Such 'fixes' can be very difficult, expensive, or perhaps impossible. Assessing constructibility should thus be a part of the iterative design process, starting with the Phase A studies and continuing through production. This study assumes that there exists a minimum set of key construction requirements (i.e., questions whose answers form the set of discriminators) that must be implied or specified in order to assess the constructibility of the design. This set of construction requirements constitutes a 'constructibility filter' which then becomes part of the iterative design process. Five inherently different, dichotomous design reference missions were used in the extraction of these requirements to assure the depth and breath of the list.

  13. Mobile robot knowledge base

    NASA Astrophysics Data System (ADS)

    Heath Pastore, Tracy; Barnes, Mitchell; Hallman, Rory

    2005-05-01

    Robot technology is developing at a rapid rate for both commercial and Department of Defense (DOD) applications. As a result, the task of managing both technology and experience information is growing. In the not-to-distant past, tracking development efforts of robot platforms, subsystems and components was not too difficult, expensive, or time consuming. To do the same today is a significant undertaking. The Mobile Robot Knowledge Base (MRKB) provides the robotics community with a web-accessible, centralized resource for sharing information, experience, and technology to more efficiently and effectively meet the needs of the robot system user. The resource includes searchable information on robot components, subsystems, mission payloads, platforms, and DOD robotics programs. In addition, the MRKB website provides a forum for technology and information transfer within the DOD robotics community and an interface for the Robotic Systems Pool (RSP). The RSP manages a collection of small teleoperated and semi-autonomous robotic platforms, available for loan to DOD and other qualified entities. The objective is to put robots in the hands of users and use the test data and fielding experience to improve robot systems.

  14. Lunar base heat pump

    NASA Technical Reports Server (NTRS)

    Goldman, Jeffrey H.; Tetreault, R.; Fischbach, D.; Walker, D.

    1994-01-01

    A heat pump is a device which elevates the temperature of a heat flow by a means of an energy input. By doing this, the heat pump can cause heat to transfer faster from a warm region to a cool region, or it can cause heat to flow from a cool region to a warmer region. The second case is the one which finds vast commercial applications such as air conditioning, heating, and refrigeration. Aerospace applications of heat pumps include both cases. The NASA Johnson Space Center is currently developing a Life Support Systems Integration Facility (LSSIF, previously SIRF) to provide system-level integration, operational test experience, and performance data that will enable NASA to develop flight-certified hardware for future planetary missions. A high lift heat pump is a significant part of the TCS hardware development associated with the LSSIF. The high lift heat pump program discussed here is being performed in three phases. In Phase 1, the objective is to develop heat pump concepts for a lunar base, a lunar lander, and for a ground development unit for the SIRF. In Phase 2, the design of the SIRF ground test unit is being performed, including identification and evaluation of safety and reliability issues. In Phase 3, the SIRF unit will be manufactured, tested, and delivered to the NASA Johnson Space Center.

  15. Graphene based GHz detectors

    NASA Astrophysics Data System (ADS)

    Boyd, Anthony K.; El Fatimy, Abdel; Barbara, Paola; Nath, Anindya; Campbell, Paul M.; Myers-Ward, Rachael; Daniels, Kevin; Gaskill, D. Kurt

    Graphene demonstrates great promise as a detector over a wide spectral range especially in the GHz range. This is because absorption is enhanced due to the Drude contribution. In the GHz range there are viable detection mechanisms for graphene devices. With this in mind, two types of GHz detectors are fabricated on epitaxial graphene using a lift off resist-based clean lithography process to produce low contact resistance. Both device types use asymmetry for detection, consistent with recent thoughts of the photothermoelectric effect (PTE) mechanism. The first is an antenna coupled device. It utilizes two dissimilar contact metals and the work function difference produces the asymmetry. The other device is a field effect transistor constructed with an asymmetric top gate that creates a PN junction and facilitates tuning the photovoltaic response. The response of both device types, tested from 100GHz to 170GHz, are reported. This work was sponsored by the U.S. Office of Naval Research (Award Number N000141310865).

  16. Alphavirus-based vaccines.

    PubMed

    Lundstrom, Kenneth

    2014-06-16

    Alphavirus vectors have demonstrated high levels of transient heterologous gene expression both in vitro and in vivo and, therefore, possess attractive features for vaccine development. The most commonly used delivery vectors are based on three single-stranded encapsulated alphaviruses, namely Semliki Forest virus, Sindbis virus and Venezuelan equine encephalitis virus. Alphavirus vectors have been applied as replication-deficient recombinant viral particles and, more recently, as replication-proficient particles. Moreover, in vitro transcribed RNA, as well as layered DNA vectors have been applied for immunization. A large number of highly immunogenic viral structural proteins expressed from alphavirus vectors have elicited strong neutralizing antibody responses in multispecies animal models. Furthermore, immunization studies have demonstrated robust protection against challenges with lethal doses of virus in rodents and primates. Similarly, vaccination with alphavirus vectors expressing tumor antigens resulted in prophylactic protection against challenges with tumor-inducing cancerous cells. As certain alphaviruses, such as Chikungunya virus, have been associated with epidemics in animals and humans, attention has also been paid to the development of vaccines against alphaviruses themselves. Recent progress in alphavirus vector development and vaccine technology has allowed conducting clinical trials in humans.

  17. Constraint-based scheduling

    NASA Technical Reports Server (NTRS)

    Zweben, Monte

    1993-01-01

    The GERRY scheduling system developed by NASA Ames with assistance from the Lockheed Space Operations Company, and the Lockheed Artificial Intelligence Center, uses a method called constraint-based iterative repair. Using this technique, one encodes both hard rules and preference criteria into data structures called constraints. GERRY repeatedly attempts to improve schedules by seeking repairs for violated constraints. The system provides a general scheduling framework which is being tested on two NASA applications. The larger of the two is the Space Shuttle Ground Processing problem which entails the scheduling of all the inspection, repair, and maintenance tasks required to prepare the orbiter for flight. The other application involves power allocation for the NASA Ames wind tunnels. Here the system will be used to schedule wind tunnel tests with the goal of minimizing power costs. In this paper, we describe the GERRY system and its application to the Space Shuttle problem. We also speculate as to how the system would be used for manufacturing, transportation, and military problems.

  18. Nanowire-based detector

    DOEpatents

    Berggren, Karl K; Hu, Xiaolong; Masciarelli, Daniele

    2014-06-24

    Systems, articles, and methods are provided related to nanowire-based detectors, which can be used for light detection in, for example, single-photon detectors. In one aspect, a variety of detectors are provided, for example one including an electrically superconductive nanowire or nanowires constructed and arranged to interact with photons to produce a detectable signal. In another aspect, fabrication methods are provided, including techniques to precisely reproduce patterns in subsequently formed layers of material using a relatively small number of fabrication steps. By precisely reproducing patterns in multiple material layers, one can form electrically insulating materials and electrically conductive materials in shapes such that incoming photons are redirected toward a nearby electrically superconductive materials (e.g., electrically superconductive nanowire(s)). For example, one or more resonance structures (e.g., comprising an electrically insulating material), which can trap electromagnetic radiation within its boundaries, can be positioned proximate the nanowire(s). The resonance structure can include, at its boundaries, electrically conductive material positioned proximate the electrically superconductive nanowire such that light that would otherwise be transmitted through the sensor is redirected toward the nanowire(s) and detected. In addition, electrically conductive material can be positioned proximate the electrically superconductive nanowire (e.g. at the aperture of the resonant structure), such that light is directed by scattering from this structure into the nanowire.

  19. Military Bases and Conservation Markets

    SciTech Connect

    Mark Ankeny

    2007-09-01

    Over time, DoD is likely to be one of the largest buyers and sellers in a water quality trading market. The Department of Defense (DoD) operates military bases that resemble small cities in infrastructure. As units redeploy, bases are likely to find themselves well within their environmental limits at the originating base and potentially bumping against limits such as nitrate and phosphate loading at the destination base. Stricter rules and heavier loadings in growing watersheds also present challenges to local bases and municipalities as regulators clamp down on loadings from existing Waste Water Treatment Plants (WWTPs) to meet water quality standards.

  20. Graphene based gene transfection

    NASA Astrophysics Data System (ADS)

    Feng, Liangzhu; Zhang, Shuai; Liu, Zhuang

    2011-03-01

    Graphene as a star in materials research has been attracting tremendous attentions in the past few years in various fields including biomedicine. In this work, for the first time we successfully use graphene as a non-toxic nano-vehicle for efficient gene transfection. Graphene oxide (GO) is bound with cationic polymers, polyethyleneimine (PEI) with two different molecular weights at 1.2 kDa and 10 kDa, forming GO-PEI-1.2k and GO-PEG-10k complexes, respectively, both of which are stable in physiological solutions. Cellular toxicity tests reveal that our GO-PEI-10k complex exhibits significantly reduced toxicity to the treated cells compared to the bare PEI-10k polymer. The positively charged GO-PEI complexes are able to further bind with plasmid DNA (pDNA) for intracellular transfection of the enhanced green fluorescence protein (EGFP) gene in HeLa cells. While EGFP transfection with PEI-1.2k appears to be ineffective, high EGFP expression is observed using the corresponding GO-PEI-1.2k as the transfection agent. On the other hand, GO-PEI-10k shows similar EGFP transfection efficiency but lower toxicity compared with PEI-10k. Our results suggest graphene to be a novel gene delivery nano-vector with low cytotoxicity and high transfection efficiency, promising for future applications in non-viral based gene therapy.Graphene as a star in materials research has been attracting tremendous attentions in the past few years in various fields including biomedicine. In this work, for the first time we successfully use graphene as a non-toxic nano-vehicle for efficient gene transfection. Graphene oxide (GO) is bound with cationic polymers, polyethyleneimine (PEI) with two different molecular weights at 1.2 kDa and 10 kDa, forming GO-PEI-1.2k and GO-PEG-10k complexes, respectively, both of which are stable in physiological solutions. Cellular toxicity tests reveal that our GO-PEI-10k complex exhibits significantly reduced toxicity to the treated cells compared to the bare PEI

  1. Measurement-based quantum communication

    NASA Astrophysics Data System (ADS)

    Zwerger, M.; Briegel, H. J.; Dür, W.

    2016-03-01

    We review and discuss the potential of using measurement-based elements in quantum communication schemes, where certain tasks are realized with the help of entangled resource states that are processed by measurements. We consider long-range quantum communication based on the transmission of encoded quantum states, where encoding, decoding and syndrome readout are implemented using small-scale resource states. We also discuss entanglement-based schemes and consider measurement-based quantum repeaters. An important element in these schemes is entanglement purification, which can also be implemented in a measurement-based way. We analyze the influence of noise and imperfections in these schemes and show that measurement-based implementation allows for very large error thresholds of the order of 10 % noise per qubit and more. We show how to obtain optimal resource states for different tasks and discuss first experimental realizations of measurement-based quantum error correction using trapped ions and photons.

  2. Carbon Nanotube Based Light Sensor

    NASA Technical Reports Server (NTRS)

    Wincheski, russell A. (Inventor); Smits, Jan M. (Inventor); Jordan, Jeffrey D. (Inventor); Watkins, Anthony Neal (Inventor); Ingram, JoAnne L. (Inventor)

    2006-01-01

    A light sensor substrate comprises a base made from a semi-conductive material and topped with a layer of an electrically non-conductive material. A first electrode and a plurality of carbon nanotube (CNT)-based conductors are positioned on the layer of electrically non-conductive material with the CNT-based conductors being distributed in a spaced apart fashion about a periphery of the first electrode. Each CNT-based conductor is coupled on one end thereof to the first electrode and extends away from the first electrode to terminate at a second free end. A second or gate electrode is positioned on the non-conductive material layer and is spaced apart from the second free end of each CNT-based conductor. Coupled to the first and second electrode is a device for detecting electron transfer along the CNT-based conductors resulting from light impinging on the CNT-based conductors.

  3. Nitrate-Dependent Degradation of Acetone by Alicycliphilus and Paracoccus Strains and Comparison of Acetone Carboxylase Enzymes ▿

    PubMed Central

    Dullius, Carlos Henrique; Chen, Ching-Yuan; Schink, Bernhard

    2011-01-01

    A novel acetone-degrading, nitrate-reducing bacterium, strain KN Bun08, was isolated from an enrichment culture with butanone and nitrate as the sole sources of carbon and energy. The cells were motile short rods, 0.5 to 1 by 1 to 2 μm in size, which gave Gram-positive staining results in the exponential growth phase and Gram-negative staining results in the stationary-growth phase. Based on 16S rRNA gene sequence analysis, the isolate was assigned to the genus Alicycliphilus. Besides butanone and acetone, the strain used numerous fatty acids as substrates. An ATP-dependent acetone-carboxylating enzyme was enriched from cell extracts of this bacterium and of Alicycliphilus denitrificans K601T by two subsequent DEAE Sepharose column procedures. For comparison, acetone carboxylases were enriched from two additional nitrate-reducing bacterial species, Paracoccus denitrificans and P. pantotrophus. The products of the carboxylase reaction were acetoacetate and AMP rather than ADP. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of cell extracts and of the various enzyme preparations revealed bands corresponding to molecular masses of 85, 78, and 20 kDa, suggesting similarities to the acetone carboxylase enzymes described in detail for the aerobic bacterium Xanthobacter autotrophicus strain Py2 (85.3, 78.3, and 19.6 kDa) and the phototrophic bacterium Rhodobacter capsulatus. Protein bands were excised and compared by mass spectrometry with those of acetone carboxylases of aerobic bacteria. The results document the finding that the nitrate-reducing bacteria studied here use acetone-carboxylating enzymes similar to those of aerobic and phototrophic bacteria. PMID:21841031

  4. Halomonas huangheensis sp. nov., a moderately halophilic bacterium isolated from a saline-alkali soil.

    PubMed

    Miao, Chaohua; Jia, Fangfang; Wan, Yusong; Zhang, Wei; Lin, Min; Jin, Wujun

    2014-03-01

    A novel, Gram-stain-negative, aerobic, rod-shaped, non-motile and moderately halophilic bacterium, designated strain BJGMM-B45(T), was isolated from a saline-alkali soil collected from Shandong Province, China. Growth of strain BJGMM-B45(T) occurred at 10-45 °C (optimum, 30 °C) and pH 5.0-12.0 (optimum, pH 7.0) on Luria-Bertani agar medium with 1-20 % (w/v) NaCl (optimum, 7-10 %). The predominant respiratory quinone was Q-9. The major cellular fatty acids (>5 %) were C18 : 1ω7c, C16 : 0, C19 : 0 cyclo ω8c, summed feature 3, C12 : 0 3-OH and C12 : 0. The genomic DNA G+C content was 57.5 mol%. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain BJGMM-B45(T) belonged to the genus Halomonas in the class Gammaproteobacteria. The closest relatives were Halomonas cupida DSM 4740(T) (98.2 % 16S rRNA gene sequence similarity) and Halomonas denitrificans M29(T) (97.8 %). Levels of DNA-DNA relatedness between strain BJGMM-B45(T) and Halomonas cupida CGMCC 1.2312(T) and Halomonas denitrificans DSM 18045(T) were 57.0 and 58.9 %, respectively. On the basis of phenotypic, chemotaxonomic and phylogenetic features, strain BJGMM-B45(T) is considered to represent a novel species of the genus Halomonas, for which the name Halomonas huangheensis sp. nov. is proposed. The type strain is BJGMM-B45(T) ( = ACCC 05850(T) = KCTC 32409(T)).

  5. Telemetry-Based Ranging

    NASA Technical Reports Server (NTRS)

    Hamkins, Jon; Vilnrotter, Victor A.; Andrews, Kenneth S.; Shambayati, Shervin

    2011-01-01

    A telemetry-based ranging scheme was developed in which the downlink ranging signal is eliminated, and the range is computed directly from the downlink telemetry signal. This is the first Deep Space Network (DSN) ranging technology that does not require the spacecraft to transmit a separate ranging signal. By contrast, the evolutionary ranging techniques used over the years by NASA missions, including sequential ranging (transmission of a sequence of sinusoids) and PN-ranging (transmission of a pseudo-noise sequence) whether regenerative (spacecraft acquires, then regenerates and retransmits a noise-free ranging signal) or transparent (spacecraft feeds the noisy demodulated uplink ranging signal into the downlink phase modulator) relied on spacecraft power and bandwidth to transmit an explicit ranging signal. The state of the art in ranging is described in an emerging CCSDS (Consultative Committee for Space Data Systems) standard, in which a pseudo-noise (PN) sequence is transmitted from the ground to the spacecraft, acquired onboard, and the PN sequence is coherently retransmitted back to the ground, where a delay measurement is made between the uplink and downlink signals. In this work, the telemetry signal is aligned with the uplink PN code epoch. The ground station computes the delay between the uplink signal transmission and the received downlink telemetry. Such a computation is feasible because symbol synchronizability is already an integral part of the telemetry design. Under existing technology, the telemetry signal cannot be used for ranging because its arrival-time information is not coherent with any Earth reference signal. By introducing this coherence, and performing joint telemetry detection and arrival-time estimation on the ground, a high-rate telemetry signal can provide all the precision necessary for spacecraft ranging.

  6. Soy-based renoprotection

    PubMed Central

    McGraw, Nancy J; Krul, Elaine S; Grunz-Borgmann, Elizabeth; Parrish, Alan R

    2016-01-01

    Chronic kidney disease (CKD) is a significant public health problem as risk factors such as advanced age, obesity, hypertension and diabetes rise in the global population. Currently there are no effective pharmacologic treatments for this disease. The role of diet is important for slowing the progression of CKD and managing symptoms in later stages of renal insufficiency. While low protein diets are generally recommended, maintaining adequate levels of intake is critical for health. There is an increasing appreciation that the source of protein may also be important. Soybean protein has been the most extensively studied plant-based protein in subjects with kidney disease and has demonstrated renal protective properties in a number of clinical studies. Soy protein consumption has been shown to slow the decline in estimated glomerular filtration rate and significantly improve proteinuria in diabetic and non-diabetic patients with nephropathy. Soy’s beneficial effects on renal function may also result from its impact on certain physiological risk factors for CKD such as dyslipidemia, hypertension and hyperglycemia. Soy intake is also associated with improvements in antioxidant status and systemic inflammation in early and late stage CKD patients. Studies conducted in animal models have helped to identify the underlying molecular mechanisms that may play a role in the positive effects of soy protein on renal parameters in polycystic kidney disease, metabolically-induced kidney dysfunction and age-associated progressive nephropathy. Despite the established relationship between soy and renoprotection, further studies are needed for a clear understanding of the role of the cellular and molecular target(s) of soy protein in maintaining renal function. PMID:27152261

  7. Velocity Based Modulus Calculations

    NASA Astrophysics Data System (ADS)

    Dickson, W. C.

    2007-12-01

    A new set of equations are derived for the modulus of elasticity E and the bulk modulus K which are dependent only upon the seismic wave propagation velocities Vp, Vs and the density ρ. The three elastic moduli, E (Young's modulus), the shear modulus μ (Lamé's second parameter) and the bulk modulus K are found to be simple functions of the density and wave propagation velocities within the material. The shear and elastic moduli are found to equal the density of the material multiplied by the square of their respective wave propagation-velocities. The bulk modulus may be calculated from the elastic modulus using Poisson's ratio. These equations and resultant values are consistent with published literature and values in both magnitude and dimension (N/m2) and are applicable to the solid, liquid and gaseous phases. A 3D modulus of elasticity model for the Parkfield segment of the San Andreas Fault is presented using data from the wavespeed model of Thurber et al. [2006]. A sharp modulus gradient is observed across the fault at seismic depths, confirming that "variation in material properties play a key role in fault segmentation and deformation style" [Eberhart-Phillips et al., 1993] [EPM93]. The three elastic moduli E, μ and K may now be calculated directly from seismic pressure and shear wave propagation velocities. These velocities may be determined using conventional seismic reflection, refraction or transmission data and techniques. These velocities may be used in turn to estimate the density. This allows velocity based modulus calculations to be used as a tool for geophysical analysis, modeling, engineering and prospecting.

  8. Lunar Base Heat Pump

    NASA Technical Reports Server (NTRS)

    Walker, D.; Fischbach, D.; Tetreault, R.

    1996-01-01

    The objective of this project was to investigate the feasibility of constructing a heat pump suitable for use as a heat rejection device in applications such as a lunar base. In this situation, direct heat rejection through the use of radiators is not possible at a temperature suitable for lde support systems. Initial analysis of a heat pump of this type called for a temperature lift of approximately 378 deg. K, which is considerably higher than is commonly called for in HVAC and refrigeration applications where heat pumps are most often employed. Also because of the variation of the rejection temperature (from 100 to 381 deg. K), extreme flexibility in the configuration and operation of the heat pump is required. A three-stage compression cycle using a refrigerant such as CFC-11 or HCFC-123 was formulated with operation possible with one, two or three stages of compression. Also, to meet the redundancy requirements, compression was divided up over multiple compressors in each stage. A control scheme was devised that allowed these multiple compressors to be operated as required so that the heat pump could perform with variable heat loads and rejection conditions. A prototype heat pump was designed and constructed to investigate the key elements of the high-lift heat pump concept. Control software was written and implemented in the prototype to allow fully automatic operation. The heat pump was capable of operation over a wide range of rejection temperatures and cooling loads, while maintaining cooling water temperature well within the required specification of 40 deg. C +/- 1.7 deg. C. This performance was verified through testing.

  9. Space-based detectors

    NASA Astrophysics Data System (ADS)

    Sesana, A.; Weber, W. J.; Killow, C. J.; Perreur-Lloyd, M.; Robertson, D. I.; Ward, H.; Fitzsimons, E. D.; Bryant, J.; Cruise, A. M.; Dixon, G.; Hoyland, D.; Smith, D.; Bogenstahl, J.; McNamara, P. W.; Gerndt, R.; Flatscher, R.; Hechenblaikner, G.; Hewitson, M.; Gerberding, O.; Barke, S.; Brause, N.; Bykov, I.; Danzmann, K.; Enggaard, A.; Gianolio, A.; Vendt Hansen, T.; Heinzel, G.; Hornstrup, A.; Jennrich, O.; Kullmann, J.; Møller-Pedersen, S.; Rasmussen, T.; Reiche, J.; Sodnik, Z.; Suess, M.; Armano, M.; Sumner, T.; Bender, P. L.; Akutsu, T.; Sathyaprakash, B. S.

    2014-12-01

    The parallel session C5 on Space-Based Detectors gave a broad overview over the planned space missions related to gravitational wave detection. Overviews of the revolutionary science to be expected from LISA was given by Alberto Sesana and Sasha Buchman. The launch of LISA Pathfinder (LPF) is planned for 2015. This mission and its payload "LISA Technology Package" will demonstrate key technologies for LISA. In this context, reference masses in free fall for LISA, and gravitational physics in general, was described by William Weber, laser interferometry at the pico-metre level and the optical bench of LPF was presented by Christian Killow and the performance of the LPF optical metrology system by Paul McNamara. While LPF will not yet be sensitive to gravitational waves, it may nevertheless be used to explore fundamental physics questions, which was discussed by Michele Armano. Some parts of the LISA technology that are not going to be demonstrated by LPF, but under intensive development at the moment, were presented by Oliver Jennrich and Oliver Gerberding. Looking into the future, Japan is studying the design of a mid-frequency detector called DECIGO, which was discussed by Tomotada Akutsu. Using atom interferometry for gravitational wave detection has also been recently proposed, and it was critically reviewed by Peter Bender. In the nearer future, the launch of GRACE Follow-On (for Earth gravity observation) is scheduled for 2017, and it will include a Laser Ranging Interferometer as technology demonstrator. This will be the first inter-spacecraft laser interferometer and has many aspects in common with the LISA long arm, as discussed by Andrew Sutton.

  10. Ferrocene-Based Nanoelectronics

    SciTech Connect

    Lawrence R. Sita

    2006-02-15

    Ferrocene-based molecular components for nanoelectronics offer a number of distinct advantages relative to all carbon frameworks due to metal-centered molecular states that should be closer in energy to the Fermi levels of the metal electrodes in metal / molecule / metal heterojunctions. Given this, the overall goal of the project was to investigate the conduction physics of a variety of proposed ferrocene diode / transistor designs in order to address the fundamental question; can electron transport within nm-length scale structures be modulated in a controlled fashion? During the funded period, substantial progress towards achieving this goal was made by surmounting a number of scientific and technical obstacles. More specifically, a concise and general synthetic route to several mono- and diferrocene dithiols and monothiols was achieved that now allows for the directed and controlled assembly of a variety of metal / molecule /metal test structures for the single molecule conductance measurements and the fabrication of self-assembled monolayers (SAMs) on Au(111) that are amenable to quantitative electrochemical characterization of electron-transfer rates. Most importantly, by using an electromigrated test structure, reproducible I/V data for one of the ferrocene dithiol molecules have been collected which exhibit surprisingly high conductance. Exceptional agreement of this result with theory serves to substantiate the original hypothesis that metal-centered states within a molecular bridge can indeed serve to establish higher conductance relative to all-organic molecular bridges. Overall, the successful demonstration of the ability of ferrocene-molecular frameworks to serve as exceptional molecular conductors will play an important role in the continued evolution in design of molecular components for nanoelectronic devices, which in turn, will have a positive impact on the science and potential technologies associated with these systems.

  11. Case-based reasoning: The marriage of knowledge base and data base

    NASA Technical Reports Server (NTRS)

    Pulaski, Kirt; Casadaban, Cyprian

    1988-01-01

    The coupling of data and knowledge has a synergistic effect when building an intelligent data base. The goal is to integrate the data and knowledge almost to the point of indistinguishability, permitting them to be used interchangeably. Examples given in this paper suggest that Case-Based Reasoning is a more integrated way to link data and knowledge than pure rule-based reasoning.

  12. XML-Based SHINE Knowledge Base Interchange Language

    NASA Technical Reports Server (NTRS)

    James, Mark; Mackey, Ryan; Tikidjian, Raffi

    2008-01-01

    The SHINE Knowledge Base Interchange Language software has been designed to more efficiently send new knowledge bases to spacecraft that have been embedded with the Spacecraft Health Inference Engine (SHINE) tool. The intention of the behavioral model is to capture most of the information generally associated with a spacecraft functional model, while specifically addressing the needs of execution within SHINE and Livingstone. As such, it has some constructs that are based on one or the other.

  13. Base pairing and base mis-pairing in nucleic acids

    NASA Technical Reports Server (NTRS)

    Wang, A. H. J.; Rich, A.

    1986-01-01

    In recent years we have learned that DNA is conformationally active. It can exist in a number of different stable conformations including both right-handed and left-handed forms. Using single crystal X-ray diffraction analysis we are able to discover not only additional conformations of the nucleic acids but also different types of hydrogen bonded base-base interactions. Although Watson-Crick base pairings are the predominant type of interaction in double helical DNA, they are not the only types. Recently, we have been able to examine mismatching of guanine-thymine base pairs in left-handed Z-DNA at atomic resolution (1A). A minimum amount of distortion of the sugar phosphate backbone is found in the G x T pairing in which the bases are held together by two hydrogen bonds in the wobble pairing interaction. Because of the high resolution of the analysis we can visualize water molecules which fill in to accommodate the other hydrogen bonding positions in the bases which are not used in the base-base interactions. Studies on other DNA oligomers have revealed that other types of non-Watson-Crick hydrogen bonding interactions can occur. In the structure of a DNA octamer with the sequence d(GCGTACGC) complexed to an antibiotic triostin A, it was found that the two central AT base pairs are held together by Hoogsteen rather than Watson-Crick base pairs. Similarly, the G x C base pairs at the ends are also Hoogsteen rather than Watson-Crick pairing. Hoogsteen base pairs make a modified helix which is distinct from the Watson-Crick double helix.

  14. Audiovisual temporal recalibration: space-based versus context-based.

    PubMed

    Yuan, Xiangyong; Li, Baolin; Bi, Cuihua; Yin, Huazhan; Huang, Xiting

    2012-01-01

    Recalibration of perceived simultaneity has been widely accepted to minimise delay between multisensory signals owing to different physical and neural conduct times. With concurrent exposure, temporal recalibration is either contextually or spatially based. Context-based recalibration was recently described in detail, but evidence for space-based recalibration is scarce. In addition, the competition between these two reference frames is unclear. Here, we examined participants who watched two distinct blob-and-tone couples that laterally alternated with one asynchronous and the other synchronous and then judged their perceived simultaneity and sequence when they swapped positions and varied in timing. For low-level stimuli with abundant auditory location cues space-based aftereffects were significantly more apparent (8.3%) than context-based aftereffects (4.2%), but without such auditory cues space-based aftereffects were less apparent (4.4%) and were numerically smaller than context-based aftereffects (6.0%). These results suggested that stimulus level and auditory location cues were both determinants of the recalibration frame. Through such joint judgments and the simple reaction time task, our results further revealed that criteria from perceived simultaneity to successiveness profoundly shifted without accompanying perceptual latency changes across adaptations, hence implying that criteria shifts, rather than perceptual latency changes, accounted for space-based and context-based temporal recalibration.

  15. Computer-based and web-based radiation safety training

    SciTech Connect

    Owen, C., LLNL

    1998-03-01

    The traditional approach to delivering radiation safety training has been to provide a stand-up lecture of the topic, with the possible aid of video, and to repeat the same material periodically. New approaches to meeting training requirements are needed to address the advent of flexible work hours and telecommuting, and to better accommodate individuals learning at their own pace. Computer- based and web-based radiation safety training can provide this alternative. Computer-based and web- based training is an interactive form of learning that the student controls, resulting in enhanced and focused learning at a time most often chosen by the student.

  16. Game-based versus traditional case-based learning

    PubMed Central

    Telner, Deanna; Bujas-Bobanovic, Maja; Chan, David; Chester, Bob; Marlow, Bernard; Meuser, James; Rothman, Arthur; Harvey, Bart

    2010-01-01

    ABSTRACT OBJECTIVE To evaluate family physicians’ enjoyment of and knowledge gained from game-based learning, compared with traditional case-based learning, in a continuing medical education (CME) event on stroke prevention and management. DESIGN An equivalence trial to determine if game-based learning was as effective as case-based learning in terms of attained knowledge levels. Game questions and small group cases were developed. Participants were randomized to either a game-based or a case-based group and took part in the event. SETTING Ontario provincial family medicine conference. PARTICIPANTS Thirty-two family physicians and 3 senior family medicine residents attending the conference. INTERVENTION Participation in either a game-based or a case-based CME learning group. MAIN OUTCOME MEASURES Scores on 40-item immediate and 3-month posttests of knowledge and a satisfaction survey. RESULTS Results from knowledge testing immediately after the event and 3 months later showed no significant difference in scoring between groups. Participants in the game-based group reported higher levels of satisfaction with the learning experience. CONCLUSION Games provide a novel way of organizing CME events. They might provide more group interaction and discussion, as well as improve recruitment to CME events. They might also provide a forum for interdisciplinary CME. Using games in future CME events appears to be a promising approach to facilitate participant learning. PMID:20841574

  17. Wavelet Features Based Fingerprint Verification

    NASA Astrophysics Data System (ADS)

    Bagadi, Shweta U.; Thalange, Asha V.; Jain, Giridhar P.

    2010-11-01

    In this work; we present a automatic fingerprint identification system based on Level 3 features. Systems based only on minutiae features do not perform well for poor quality images. In practice, we often encounter extremely dry, wet fingerprint images with cuts, warts, etc. Due to such fingerprints, minutiae based systems show poor performance for real time authentication applications. To alleviate the problem of poor quality fingerprints, and to improve overall performance of the system, this paper proposes fingerprint verification based on wavelet statistical features & co-occurrence matrix features. The features include mean, standard deviation, energy, entropy, contrast, local homogeneity, cluster shade, cluster prominence, Information measure of correlation. In this method, matching can be done between the input image and the stored template without exhaustive search using the extracted feature. The wavelet transform based approach is better than the existing minutiae based method and it takes less response time and hence suitable for on-line verification, with high accuracy.

  18. Logistics support of lunar bases

    NASA Astrophysics Data System (ADS)

    Woodcock, Gordon R.

    Concepts for lunar base design and operations have been studied for over twenty years. A brief summary of past concepts is presented, with reference to new ideas on design, uses and logistics schemes. Transportation systems and mission modes are reviewed, showing the significant cost benefits of reusable transportation at the higher traffic rates representative of lunar base buildup and logistics operations. Parametric studies are presented over the range of base size from 6 crew to 1000 crew, and the "choke points", or barriers to growth are identified and means for their resolution presented. The leverages of food growth on the Moon, crew stay time, use of lunar oxygen, indigenous resources for construction of facilities, and transportation systems size and operations modes are presented. It is concluded that bases as large as 1000 people are affordable at less than twice the cost of an initial base of six people if these leverages of advanced basing technologies are exploited.

  19. Concurrent array-based queue

    SciTech Connect

    Heidelberger, Philip; Steinmacher-Burow, Burkhard

    2015-01-06

    According to one embodiment, a method for implementing an array-based queue in memory of a memory system that includes a controller includes configuring, in the memory, metadata of the array-based queue. The configuring comprises defining, in metadata, an array start location in the memory for the array-based queue, defining, in the metadata, an array size for the array-based queue, defining, in the metadata, a queue top for the array-based queue and defining, in the metadata, a queue bottom for the array-based queue. The method also includes the controller serving a request for an operation on the queue, the request providing the location in the memory of the metadata of the queue.

  20. Principles of models based engineering

    SciTech Connect

    Dolin, R.M.; Hefele, J.

    1996-11-01

    This report describes a Models Based Engineering (MBE) philosophy and implementation strategy that has been developed at Los Alamos National Laboratory`s Center for Advanced Engineering Technology. A major theme in this discussion is that models based engineering is an information management technology enabling the development of information driven engineering. Unlike other information management technologies, models based engineering encompasses the breadth of engineering information, from design intent through product definition to consumer application.

  1. Base Camp Design Simulation Training

    DTIC Science & Technology

    2011-07-01

    It is a treasure-trove of engineering blueprints, bill of materials ( BOMs ), and plans. This 600- man base camp, Figure 6, inputted into VBS2TM...the technical proficiencies required in the construction of base camps. There are no blue prints or bill of materials included in the training. Yet...that “base camps need DOTMLPF (doctrine, organization, training, material , leadership and education, personnel, and facilities) solutions to address

  2. dBASE IV basics

    SciTech Connect

    O`Connor, P.

    1994-09-01

    This is a user`s manual for dBASE IV. dBASE IV is a popular software application that can be used on your personal computer to help organize and maintain your database files. It is actually a set of tools with which you can create, organize, select and manipulate data in a simple yet effective manner. dBASE IV offers three methods of working with the product: (1) control center: (2) command line; and (3) programming.

  3. Evidence-Based Medicine: Rhinoplasty.

    PubMed

    Lee, Matthew K; Most, Sam P

    2015-08-01

    Evidence-based medicine has become increasingly prominent in the climate of modern day healthcare. The practice of evidence-based medicine involves the integration of the best available evidence with clinical experience and expertise to help guide clinical decision-making. The essential tenets of evidence-based medicine can be applied to both functional and aesthetic rhinoplasty. Current outcome measures in functional and aesthetic rhinoplasty, including objective, subjective, and clinician-reported measures, is summarized and the current data is reviewed.

  4. Brain-Based Learning and Standards-Based Elementary Science.

    ERIC Educational Resources Information Center

    Konecki, Loretta R.; Schiller, Ellen

    This paper explains how brain-based learning has become an area of interest to elementary school science teachers, focusing on the possible relationships between, and implications of, research on brain-based learning to the teaching of science education standards. After describing research on the brain, the paper looks at three implications from…

  5. Theory-Based Stakeholder Evaluation

    ERIC Educational Resources Information Center

    Hansen, Morten Balle; Vedung, Evert

    2010-01-01

    This article introduces a new approach to program theory evaluation called theory-based stakeholder evaluation or the TSE model for short. Most theory-based approaches are program theory driven and some are stakeholder oriented as well. Practically, all of the latter fuse the program perceptions of the various stakeholder groups into one unitary…

  6. Estolides: Bioderived synthetic base oils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One novel technology to reach the lubricant market in recent years is the estolide, a class of high-performance, environmentally acceptable lubricant base oils. Estolides have been tested against a set of similar competing base oils from the marketplace, and the results show that they have excellent...

  7. Electrorheological Material Based Smart Structures

    DTIC Science & Technology

    2007-11-02

    based in-situ structural vibration monitoring, and real-time neural network based vibration control. In order to facilitate the basic science...structural vibration model was developed and tested with corresponding experimentation. Novel fiber-optic sensors and neural network controllers were also

  8. Problem-Based Learning Tools

    ERIC Educational Resources Information Center

    Chin, Christine; Chia, Li-Gek

    2008-01-01

    One way of implementing project-based science (PBS) is to use problem-based learning (PBL), in which students formulate their own problems. These problems are often ill-structured, mirroring complex real-life problems where data are often messy and inclusive. In this article, the authors describe how they used PBL in a ninth-grade biology class in…

  9. Competency Based Education: A Bibliography.

    ERIC Educational Resources Information Center

    Cox, Helen, Ed.

    This bibliography is a sampling of the types of publications which have appeared recently on the subject of competency based education. Emphasis is given to current (1970-76) materials and to adult career-related competencies. Titles specifically naming some phase of competency-based education are preferred above titles that emphasize performance,…

  10. Constraint-Based Scheduling System

    NASA Technical Reports Server (NTRS)

    Zweben, Monte; Eskey, Megan; Stock, Todd; Taylor, Will; Kanefsky, Bob; Drascher, Ellen; Deale, Michael; Daun, Brian; Davis, Gene

    1995-01-01

    Report describes continuing development of software for constraint-based scheduling system implemented eventually on massively parallel computer. Based on machine learning as means of improving scheduling. Designed to learn when to change search strategy by analyzing search progress and learning general conditions under which resource bottleneck occurs.

  11. Isomap based supporting vector machine

    NASA Astrophysics Data System (ADS)

    Liang, W. N.

    2015-12-01

    This research presents a new isomap based supporting vector machine method. Isomap is a dimension reduction method which is able to analyze nonlinear relationship of data on manifolds. Accordingly, support vector machine is established on the isomap manifold to classify given and predict unknown data. A case study of the isomap based supporting vector machine for environmental planning problems is conducted.

  12. Cloud-Based Data Storage

    ERIC Educational Resources Information Center

    Waters, John K.

    2011-01-01

    The vulnerability and inefficiency of backing up data on-site is prompting school districts to switch to more secure, less troublesome cloud-based options. District auditors are pushing for a better way to back up their data than the on-site, tape-based system that had been used for years. About three years ago, Hendrick School District in…

  13. Dog Mathematics: Exploring Base-4

    ERIC Educational Resources Information Center

    Kurz, Terri L.; Yanik, H. Bahadir; Lee, Mi Yeon

    2016-01-01

    Using a dog's paw as a basis for numerical representation, sixth grade students explored how to count and regroup using the dog's four digital pads. Teachers can connect these base-4 explorations to the conceptual meaning of place value and regrouping using base-10.

  14. Discipline Based Arts Education. [Videotape].

    ERIC Educational Resources Information Center

    Phillips, Lori

    This 5-part video lesson deals with discipline-based art education in the elementary school. The video features a university professor who is a specialist in methods and the integration of art into the elementary classroom; each part of the video lesson is 30 minutes in length. First defining discipline-based art education as an approach, not a…

  15. Computer-Based Hindi Pedagogy.

    ERIC Educational Resources Information Center

    Bhatia, Tej K.

    This paper brings out the structure and salient features of the Computer-Based Hindi Teaching (CBHT) course, which is being developed at the University of Illinois. The following topics are treated specifically: (1) areas of the Hindi Language course that can be efficiently and economically taught with computer-based pedagogy; (2) a demonstration…

  16. Plasma-based accelerator structures

    SciTech Connect

    Schroeder, Carl B.

    1999-12-01

    Plasma-based accelerators have the ability to sustain extremely large accelerating gradients, with possible high-energy physics applications. This dissertation further develops the theory of plasma-based accelerators by addressing three topics: the performance of a hollow plasma channel as an accelerating structure, the generation of ultrashort electron bunches, and the propagation of laser pulses is underdense plasmas.

  17. Using dBase III.

    ERIC Educational Resources Information Center

    Evans, Janet; And Others

    1986-01-01

    Four articles on dBASE III include three on library applications: a photocopy invoicing system for interlibrary loan, a vertical file subject headings list program, and a subject index to statistical resources. Another article explains the differences between interpreters and compilers and the advantages of the Clipper compiler for dBASE III. (EM)

  18. C-21 Fleet: Base Optimization

    DTIC Science & Technology

    assigned to the operational support airlift mission, located at Andrews Air Force Base, Maryland and Scott Air Force Base, Illinois. The missions flown... Scott and Andrews AFB is the optimal assignment. If nine total assets were optimized, five would be assigned to Scott AFB and four to Andrews AFB

  19. Lignin-Based Thermoplastic Materials.

    PubMed

    Wang, Chao; Kelley, Stephen S; Venditti, Richard A

    2016-04-21

    Lignin-based thermoplastic materials have attracted increasing interest as sustainable, cost-effective, and biodegradable alternatives for petroleum-based thermoplastics. As an amorphous thermoplastic material, lignin has a relatively high glass-transition temperature and also undergoes radical-induced self-condensation at high temperatures, which limits its thermal processability. Additionally, lignin-based materials are usually brittle and exhibit poor mechanical properties. To improve the thermoplasticity and mechanical properties of technical lignin, polymers or plasticizers are usually integrated with lignin by blending or chemical modification. This Review attempts to cover the reported approaches towards the development of lignin-based thermoplastic materials on the basis of published information. Approaches reviewed include plasticization, blending with miscible polymers, and chemical modifications by esterification, etherification, polymer grafting, and copolymerization. Those lignin-based thermoplastic materials are expected to show applications as engineering plastics, polymeric foams, thermoplastic elastomers, and carbon-fiber precursors.

  20. Colloidal nanomaterial-based immunoassay.

    PubMed

    Teste, Bruno; Descroix, Stephanie

    2012-06-01

    Nanomaterials have been widely developed for their use in nanomedicine, especially for immunoassay-based diagnosis. In this review we focus on the use of nanomaterials as a nanoplatform for colloidal immunoassays. While conventional heterogeneous immunoassays suffer from mass transfer limitations and consequently long assay time, colloidal immunosupports allow target capture in the entire volume, thus speeding up reaction kinetics and shortening assay time. Owing to their wide range of chemical and physical properties, nanomaterials are an interesting candidate for immunoassay development. The most popular colloidal nanomaterials for colloidal immunoassays will be discussed, as well as their influence on immune reactions. Recent advances in nanomaterial applications for different formats of immunoassays will be reported, such as nanomaterial-based indirect immunoassays, optical-based agglutination immunoassays, resonance energy transfer-based immunoassays and magnetic relaxation-based immunoassays. Finally, the future of using nanomaterials for homogeneous immunoassays dedicated to clinical diagnosis will be discussed.

  1. Object-based media and stream-based computing

    NASA Astrophysics Data System (ADS)

    Bove, V. Michael, Jr.

    1998-03-01

    Object-based media refers to the representation of audiovisual information as a collection of objects - the result of scene-analysis algorithms - and a script describing how they are to be rendered for display. Such multimedia presentations can adapt to viewing circumstances as well as to viewer preferences and behavior, and can provide a richer link between content creator and consumer. With faster networks and processors, such ideas become applicable to live interpersonal communications as well, creating a more natural and productive alternative to traditional videoconferencing. In this paper is outlined an example of object-based media algorithms and applications developed by my group, and present new hardware architectures and software methods that we have developed to enable meeting the computational requirements of object- based and other advanced media representations. In particular we describe stream-based processing, which enables automatic run-time parallelization of multidimensional signal processing tasks even given heterogenous computational resources.

  2. Value-based metrics and Internet-based enterprises

    NASA Astrophysics Data System (ADS)

    Gupta, Krishan M.

    2001-10-01

    Within the last few years, a host of value-based metrics like EVA, MVA, TBR, CFORI, and TSR have evolved. This paper attempts to analyze the validity and applicability of EVA and Balanced Scorecard for Internet based organizations. Despite the collapse of the dot-com model, the firms engaged in e- commerce continue to struggle to find new ways to account for customer-base, technology, employees, knowledge, etc, as part of the value of the firm. While some metrics, like the Balance Scorecard are geared towards internal use, others like EVA are for external use. Value-based metrics are used for performing internal audits as well as comparing firms against one another; and can also be effectively utilized by individuals outside the firm looking to determine if the firm is creating value for its stakeholders.

  3. Outcome-based and Participation-based Wellness Incentives

    PubMed Central

    Barleen, Nathan A.; Marzec, Mary L.; Boerger, Nicholas L.; Moloney, Daniel P.; Zimmerman, Eric M.; Dobro, Jeff

    2017-01-01

    Objective: This study examined whether worksite wellness program participation or achievement of health improvement targets differed according to four incentive types (participation-based, hybrid, outcome-based, and no incentive). Methods: The study included individuals who completed biometric health screenings in both 2013 and 2014 and had elevated metrics in 2013 (baseline year). Multivariate logistic regression modeling tested for differences in odds of participation and achievement of health improvement targets between incentive groups; controlling for demographics, employer characteristics, incentive amounts, and other factors. Results: No statistically significant differences between incentive groups occurred for odds of participation or achievement of health improvement target related to body mass index, blood pressure, or nonhigh-density lipoprotein cholesterol. Conclusions: Given the null findings of this study, employers cannot assume that outcome-based incentives will result in either increased program participation or greater achievement of health improvement targets than participation-based incentives. PMID:28146041

  4. Coronavirus phylogeny based on triplets of nucleic acids bases

    NASA Astrophysics Data System (ADS)

    Liao, Bo; Liu, Yanshu; Li, Renfa; Zhu, Wen

    2006-04-01

    We considered the fully overlapping triplets of nucleotide bases and proposed a 2D graphical representation of protein sequences consisting of 20 amino acids and a stop code. Based on this 2D graphical representation, we outlined a new approach to analyze the phylogenetic relationships of coronaviruses by constructing a covariance matrix. The evolutionary distances are obtained through measuring the differences among the two-dimensional curves.

  5. Mineral-resource data bases

    USGS Publications Warehouse

    ,

    1997-01-01

    Data bases are essential for modern scientific research. The new and exciting work being done in the Mineral Resource Program in the U.S. Geological Survey (USGS) usually begins with the question, "Where are the known deposits?" A mineral-resource data base containing this type of information and more can be useful not just to USGS scientists, but to anyone who needs such data. Users of the data bases from outside the USGS include mining and exploration companies, environmental groups, academia, other Federal Agencies, and the general public. At present, the USGS has two large mineral-resource data bases, MRDS (Mineral Resource Data System) and MAS (Minerals Availability System). MRDS was built and is mamtained by the USGS, and MAS was built and maintained by the Bureau of Mines. In 1996, after the Bureau was abolished, MAS was transferred to the USGS. The two data bases were compiled for different purposes and contain very different mformation. For instance, MAS contains information on costs, details of mining methods, and feasibility studies. MRDS has mineralogical and geologic data that are not contained in MAS. Because they are both mineral-resource data bases, however, they contain some information in common, such as location, name(s) of sites, and commodities present. Both data bases are international in scope, and both are quite large. MRDS contains over 110,000 records, while MAS has over 220,000. One reason that MAS has more records is that it contains information on smelters, mill sites, and fossil fuel sites, as well as mineral- resource sites. The USGS is working to combine the information in both data bases. This is a large undertaking that will require some years to complete. In the interim, information from both data bases will still be available

  6. Interactions between space-based and feature-based attention

    PubMed Central

    Leonard, Carly J.; Balestreri, Angela; Luck, Steven J.

    2014-01-01

    Although early research suggested that attention to nonspatial features (i.e., red) was confined to stimuli appearing at an attended spatial location, more recent research has emphasized the global nature of feature-based attention. For example, a distractor sharing a target feature may capture attention even if it occurs at a task-irrelevant location. Such findings have been used to argue that feature-based attention operates independently of spatial attention. However, feature-based attention may nonetheless interact with spatial attention, yielding larger feature-based effects at attended locations than at unattended locations. The present study tested this possibility. In two experiments, participants viewed a rapid serial visual presentation (RSVP) stream and identified a target letter defined by its color. Target-colored distractors were presented at various task-irrelevant locations during the RSVP stream. We found that feature-driven attentional capture effects were largest when the target-colored distractor was closer to the attended location. These results demonstrate that spatial attention modulates the strength of feature-based attention capture, calling into question the prior evidence that feature-based attention operates in a global manner that is independent of spatial attention. PMID:25285472

  7. New carbohydrate-based materials

    SciTech Connect

    Callstrom, M.R.

    1992-07-01

    We have prepared a series of new carbohydrate-based materials based on the use of carbohydrates as a template for the introduction of functionality to polymeric materials with complete regio- and stereochemical control. The synthesis of these new materials by the use of chemical and enzymatic methods allows for the rational design of new materials based on the properties of the monomeric subunit. These materials have potential applications that range from their use in enhanced oil recovery to biodegradable plastics to biological applications including targeted drug delivery and enzyme stabilization.

  8. DSP based data acquisition system

    NASA Astrophysics Data System (ADS)

    Prasad, Peeyush; Subrahmanya, C. R.

    A new DSP based data acquisition system based on commercial, off-the-shelf available hardware is presented. The board features friendly high speed input and output interfaces, a powerful DSP and hardware offloading of essing to an FPGA. For flexibility of development, a soft realtime linux based kernel popular among embedded developers (uClinux) has been ported on the board.The development environment is fully open source both for the target as well as for host software. The motivation behind creating the system, the development ess and the current status is described. Some results obtained with this system as used in typical applications are also presented.

  9. The computer-based lecture.

    PubMed

    Wofford, M M; Spickard, A W; Wofford, J L

    2001-07-01

    Advancing computer technology, cost-containment pressures, and desire to make innovative improvements in medical education argue for moving learning resources to the computer. A reasonable target for such a strategy is the traditional clinical lecture. The purpose of the lecture, the advantages and disadvantages of "live" versus computer-based lectures, and the technical options in computerizing the lecture deserve attention in developing a cost-effective, complementary learning strategy that preserves the teacher-learner relationship. Based on a literature review of the traditional clinical lecture, we build on the strengths of the lecture format and discuss strategies for converting the lecture to a computer-based learning presentation.

  10. School-Based Health Centers

    MedlinePlus

    ... the hall. Staffed by health care workers like nurses and doctors, school-based health centers provide a ... including mental health care. Centers may even have nurse practitioners, medical students, doctors, social workers, drug counselors, ...

  11. Community-Based Biofuel Program

    EPA Pesticide Factsheets

    Monroe County, New York, is an EPA Climate Showcase Community. EPA’s Climate Showcase Communities Program helps local governments and tribal nations pilot innovative, cost-effective and replicable community-based greenhouse gas reduction projects.

  12. Improvements in bracket base design.

    PubMed

    Smith, D C; Maijer, R

    1983-04-01

    Acid etch bonding of orthodontic attachments to the labial and lingual surfaces of teeth is generally adequate for clinical service. Failures do occur, and these are related to technique problems in acid etching or resin manipulation or to bracket base design. The widely used foil mesh base can present problems in retention because of design defects or corrosion. Improvement in mechanical retention of resin to the attachment base would result in significant improvements in bonding and fewer clinical failures. One of our approaches to improved retention is to fuse metallic or ceramic particles onto the bracket base so as to achieve a particulate or porous layer into which resin can penetrate. The results of bond-strength tests showed that a 100 percent increase in bond strength could be obtained with sintered porous metal-coated brackets. Further development is proceeding.

  13. Double-Base Binder Improvement

    DTIC Science & Technology

    The general objective of this program is to improve the mechanical properties of composite modified double base ( CMDB ) propellants, with particular emphasis upon those prepared by the slurry cast process.

  14. Surface stress-based biosensors.

    PubMed

    Sang, Shengbo; Zhao, Yuan; Zhang, Wendong; Li, Pengwei; Hu, Jie; Li, Gang

    2014-01-15

    Surface stress-based biosensors, as one kind of label-free biosensors, have attracted lots of attention in the process of information gathering and measurement for the biological, chemical and medical application with the development of technology and society. This kind of biosensors offers many advantages such as short response time (less than milliseconds) and a typical sensitivity at nanogram, picoliter, femtojoule and attomolar level. Furthermore, it simplifies sample preparation and testing procedures. In this work, progress made towards the use of surface stress-based biosensors for achieving better performance is critically reviewed, including our recent achievement, the optimally circular membrane-based biosensors and biosensor array. The further scientific and technological challenges in this field are also summarized. Critical remark and future steps towards the ultimate surface stress-based biosensors are addressed.

  15. Probing Microcomputer-Based Laboratories.

    ERIC Educational Resources Information Center

    Lam, Tom

    1985-01-01

    Microcomputer-based laboratories (MBLs) refer to a laboratory where a microcomputer gathers and displays data directly from the environment. Program listings for a response timer (using game paddles) to illustrate the nature of MBLs are presented. (JN)

  16. Pitch based foam with particulate

    DOEpatents

    Klett, James W.

    2001-01-01

    A thermally conductive, pitch based foam composite having a particulate content. The particulate alters the mechanical characteristics of the foam without severely degrading the foam thermal conductivity. The composite is formed by mixing the particulate with pitch prior to foaming.

  17. Classifying Chondrules Based on Cathodoluminesence

    NASA Astrophysics Data System (ADS)

    Cristarela, T. C.; Sears, D. W.

    2011-03-01

    Sears et al. (1991) proposed a scheme to classify chondrules based on cathodoluminesence color and electron microprobe analysis. This research evaluates that scheme and criticisms received from Grossman and Brearley (2005).

  18. Chip-based droplet sorting

    SciTech Connect

    Beer, Neil Reginald; Lee, Abraham; Hatch, Andrew

    2014-07-01

    A non-contact system for sorting monodisperse water-in-oil emulsion droplets in a microfluidic device based on the droplet's contents and their interaction with an applied electromagnetic field or by identification and sorting.

  19. Contingency Base Energy Management System

    SciTech Connect

    2016-06-09

    CB-EMS is the latest implementation of DSOM (Decision Support for Operations and Maintenance), which was previously patented by PNNL. CB-EMS WAS specifically designed for contingency bases for the US Army. It is a software package that is designed to monitor energy consumption at an Army contingency base to alert the camp manager when the systems are wasting energy. It's main feature that separates it from DSOM is it's ability to add systems using a plug and play menu system.

  20. Voltage Identify Based Encryption (VIBE)

    DTIC Science & Technology

    2005-03-01

    PUBLIC RELEASE; DISTRIBUTION UNLIMITED. 13. ABSTRACT (Maximum 200 Words) Invented by Dr. Dan Boneh and Dr. Matt Franklin in 2001, Identity-Based...20 Introduction Invented by Dr. Dan Boneh and Dr. Matt Franklin in 2001, Identity-Based Encryption or IBE, is a breakthrough in...the effectiveness of the technology developed to implement the Boneh -Franklin IBE. This contract provided for the necessary hardware and software

  1. Evidence-Based Cancer Imaging

    PubMed Central

    Khorasani, Ramin

    2017-01-01

    With the advances in the field of oncology, imaging is increasingly used in the follow-up of cancer patients, leading to concerns about over-utilization. Therefore, it has become imperative to make imaging more evidence-based, efficient, cost-effective and equitable. This review explores the strategies and tools to make diagnostic imaging more evidence-based, mainly in the context of follow-up of cancer patients. PMID:28096722

  2. Proanthocyanidin-based Endotoxin Removal

    DTIC Science & Technology

    2014-01-16

    Naval Research Laboratory Washington, DC 20375-5320 Proanthocyanidin-based Endotoxin Removal January 16, 2014 Approved for public release...17. LIMITATION OF ABSTRACT Proanthocyanidin-based Endotoxin Removal Brandy J. White, James B. Delehanty, Baochuan Lin, and George P. Anderson Naval...Unclassified Unclassified Unclassified SAR 20 Brandy J. White (202) 404-6100 The application of proanthocyanidins (PACs) to the capture and removal of

  3. Knowledge-Based Image Analysis.

    DTIC Science & Technology

    1981-04-01

    UNCLASSIF1 ED ETL-025s N IIp ETL-0258 AL Ai01319 S"Knowledge-based image analysis u George C. Stockman Barbara A. Lambird I David Lavine Laveen N. Kanal...extraction, verification, region classification, pattern recognition, image analysis . 3 20. A. CT (Continue on rever.. d. It necessary and Identify by...UNCLgSTFTF n In f SECURITY CLASSIFICATION OF THIS PAGE (When Date Entered) .L1 - I Table of Contents Knowledge Based Image Analysis I Preface

  4. Osmium-Based Pyrimidine Contrast Tags for Enhanced Nanopore-Based DNA Base Discrimination.

    PubMed

    Henley, Robert Y; Vazquez-Pagan, Ana G; Johnson, Michael; Kanavarioti, Anastassia; Wanunu, Meni

    2015-01-01

    Nanopores are a promising platform in next generation DNA sequencing. In this platform, an individual DNA strand is threaded into nanopore using an electric field, and enzyme-based ratcheting is used to move the strand through the detector. During this process the residual ion current through the pore is measured, which exhibits unique levels for different base combinations inside the pore. While this approach has shown great promise, accuracy is not optimal because the four bases are chemically comparable to one another, leading to small differences in current obstruction. Nucleobase-specific chemical tagging can be a viable approach to enhancing the contrast between different bases in the sequence. Herein we show that covalent modification of one or both of the pyrimidine bases by an osmium bipyridine complex leads to measureable differences in the blockade amplitudes of DNA molecules. We qualitatively determine the degree of osmylation of a DNA strand by passing it through a solid-state nanopore, and are thus able to gauge T and C base content. In addition, we show that osmium bipyridine reacts with dsDNA, leading to substantially different current blockade levels than exhibited for bare dsDNA. This work serves as a proof of principle for nanopore sequencing and mapping via base-specific DNA osmylation.

  5. NLS base heating CFD analysis

    NASA Technical Reports Server (NTRS)

    Ascoli, Edward P.; Heiba, Adel H.; Hsu, Yann-Fu; Lagnado, Ronald R.; Lynch, Edward D.

    1993-01-01

    Concerns raised over possible base heating effects on the National Launch System (NLS) 1.5 stage reference vehicle resulted in the use of CFD as a predictive analysis tool. The objective established was to obtain good engineering solutions to describe the base region flowfields at 10,000 ft and 50,000 ft altitudes. The Rockwell USA CFD code was employed with a zero-equation turbulence model and a four species, 1 step chemical kinetics package. Three solutions were generated for the specified altitudes on coarse and fine grids. CFD results show the base region flowfields to be highly three dimensional in character. At the 10,000 ft altitude, plumes contract soon after exiting the nozzles and do not interact with each other. No mechanism was identified for driving hot gas back into the base region and no significant amounts of hydrogen or water were found in the base region. Consequently, surface temperatures were all near the ambient level. At 50,000 ft, the nozzle exhaust plumes begin to interact, particularly those of the two inboard engines which are closer together. A small amount of hot gas is recirculated between the inboard nozzles near the nozzle exit plane. As a result, base region surface temperatures are slightly elevated, but still remain well within the design guideline of 1000 R.

  6. NLS base heating CFD analysis

    NASA Astrophysics Data System (ADS)

    Ascoli, Edward P.; Heiba, Adel H.; Hsu, Yann-Fu; Lagnado, Ronald R.; Lynch, Edward D.

    1993-07-01

    Concerns raised over possible base heating effects on the National Launch System (NLS) 1.5 stage reference vehicle resulted in the use of CFD as a predictive analysis tool. The objective established was to obtain good engineering solutions to describe the base region flowfields at 10,000 ft and 50,000 ft altitudes. The Rockwell USA CFD code was employed with a zero-equation turbulence model and a four species, 1 step chemical kinetics package. Three solutions were generated for the specified altitudes on coarse and fine grids. CFD results show the base region flowfields to be highly three dimensional in character. At the 10,000 ft altitude, plumes contract soon after exiting the nozzles and do not interact with each other. No mechanism was identified for driving hot gas back into the base region and no significant amounts of hydrogen or water were found in the base region. Consequently, surface temperatures were all near the ambient level. At 50,000 ft, the nozzle exhaust plumes begin to interact, particularly those of the two inboard engines which are closer together. A small amount of hot gas is recirculated between the inboard nozzles near the nozzle exit plane. As a result, base region surface temperatures are slightly elevated, but still remain well within the design guideline of 1000 R.

  7. Centrifuge-Based Fluidic Platforms

    NASA Astrophysics Data System (ADS)

    Zoval, Jim; Jia, Guangyao; Kido, Horacio; Kim, Jitae; Kim, Nahui; Madou, Marc

    In this chapter centrifuge-based microfluidic platforms are reviewed and compared with other popular microfluidic propulsion methods. The underlying physical principles of centrifugal pumping in microfluidic systems are presented and the various centrifuge fluidic functions such as valving, decanting, calibration, mixing, metering, heating, sample splitting, and separation are introduced. Those fluidic functions have been combined with analytical measurements techniques such as optical imaging, absorbance and fluorescence spectroscopy and mass spectrometry to make the centrifugal platform a powerful solution for medical and clinical diagnostics and high-throughput screening (HTS) in drug discovery. Applications of a compact disc (CD)-based centrifuge platform analyzed in this review include: two-point calibration of an optode-based ion sensor, an automated immunoassay platform, multiple parallel screening assays and cellular-based assays. The use of modified commercial CD drives for high-resolution optical imaging is discussed as well. From a broader perspective, we compare the technical barriers involved in applying microfluidics for sensing and diagnostic as opposed to applying such techniques to HTS. The latter poses less challenges and explains why HTS products based on a CD fluidic platform are already commercially available, while we might have to wait longer to see commercial CD-based diagnostics.

  8. A comprehensive physiologically based pharmacokinetic ...

    EPA Pesticide Factsheets

    Published physiologically based pharmacokinetic (PBPK) models from peer-reviewed articles are often well-parameterized, thoroughly-vetted, and can be utilized as excellent resources for the construction of models pertaining to related chemicals. Specifically, chemical-specific parameters and in vivo pharmacokinetic data used to calibrate these published models can act as valuable starting points for model development of new chemicals with similar molecular structures. A knowledgebase for published PBPK-related articles was compiled to support PBPK model construction for new chemicals based on their close analogues within the knowledgebase, and a web-based interface was developed to allow users to query those close analogues. A list of 689 unique chemicals and their corresponding 1751 articles was created after analysis of 2,245 PBPK-related articles. For each model, the PMID, chemical name, major metabolites, species, gender, life stages and tissue compartments were extracted from the published articles. PaDEL-Descriptor, a Chemistry Development Kit based software, was used to calculate molecular fingerprints. Tanimoto index was implemented in the user interface as measurement of structural similarity. The utility of the PBPK knowledgebase and web-based user interface was demonstrated using two case studies with ethylbenzene and gefitinib. Our PBPK knowledgebase is a novel tool for ranking chemicals based on similarities to other chemicals associated with existi

  9. Current NASA lunar base concepts

    NASA Technical Reports Server (NTRS)

    Roberts, Barney B.; Connolly, John F.

    1990-01-01

    The NASA Office of Aeronautics, Exploration, and Technology has completed a Systems Engineering and Integration effort to define a point design for an evolving lunar base that supports substantial science, exploration, and resource production objectives. This study addressed the following: systems level design; element requirements and conceptual design; assessments of precursor and technology needs; and operations concepts. The central base is assumed to be located equatorially on the lunar nearside north of the crater Moltke in Mare Tranquilliatis. The study considers an aggressive case with three main phases. The initial Man-Tended Phase established basic enabling facilities that include a modular habitat that periodically houses a crew of four. During the Experimental Phase, the base becomes permanently manned with the construction of a larger habitat that provides augmented workshop and laboratory volumes and housing for crew. The Operational Phase expands base capabilities to a substantially mature level while reducing reliance on Earth. The analysis classifies base characteristics into several major functional areas: Human Systems; Assembly and Construction; Energy Management; Launch and Landing; Surface Transportation; In-Situ Resources Utilization; User Accommodations; and Telecommunications, Navigation, and Information Management. Results of various NASA-sponsored studies were synthesized to meet requirements. The system level architecture was determined, the physical layout was developed from a set of proximity criteria and related functions, and the evlotuionary path of the base was analyzed. Conclusions include a summary of technology needs, design drivers, high leverage items, and important issues.

  10. Rule-based simulation models

    NASA Technical Reports Server (NTRS)

    Nieten, Joseph L.; Seraphine, Kathleen M.

    1991-01-01

    Procedural modeling systems, rule based modeling systems, and a method for converting a procedural model to a rule based model are described. Simulation models are used to represent real time engineering systems. A real time system can be represented by a set of equations or functions connected so that they perform in the same manner as the actual system. Most modeling system languages are based on FORTRAN or some other procedural language. Therefore, they must be enhanced with a reaction capability. Rule based systems are reactive by definition. Once the engineering system has been decomposed into a set of calculations using only basic algebraic unary operations, a knowledge network of calculations and functions can be constructed. The knowledge network required by a rule based system can be generated by a knowledge acquisition tool or a source level compiler. The compiler would take an existing model source file, a syntax template, and a symbol table and generate the knowledge network. Thus, existing procedural models can be translated and executed by a rule based system. Neural models can be provide the high capacity data manipulation required by the most complex real time models.

  11. Nucleotide Sequences and Comparison of Two Large Conjugative Plasmids from Different Campylobacter species

    DTIC Science & Technology

    2004-01-01

    Burkholderia cepacia ; C. jejuni, Campylobacter jejuni; C. crescentus, Caulobacter crescen- tus; C. hutchinsonii, Cytophaga hutchinsonii; E. faecalis...and pCC31 plasmids and the closest relationships to previously studied proteins A. denitrificans, Achromobacter denitrificans; B. cepacia ...23/51%); (20/48%) cpp13 88/88 + cpp14 1932/1932 + (B. cepacia , NZ_AAEH01000008) (42/62%); (42/62%) cpp15 2/242 + None; HP1334 (H. pylori, AAD08389

  12. Home-based versus centre-based cardiac rehabilitation

    PubMed Central

    Taylor, Rod S; Dalal, Hayes; Jolly, Kate; Moxham, Tiffany; Zawada, Anna

    2014-01-01

    Background The burden of cardiovascular disease world-wide is one of great concern to patients and health care agencies alike. Traditionally centre-based cardiac rehabilitation (CR) programmes are offered to individuals after cardiac events to aid recovery and prevent further cardiac illness. Home-based cardiac rehabilitation programmes have been introduced in an attempt to widen access and participation. Objectives To determine the effectiveness of home-based cardiac rehabilitation programmes compared with supervised centre-based cardiac rehabilitation on mortality and morbidity, health-related quality of life and modifiable cardiac risk factors in patients with coronary heart disease. Search methods We updated the search of a previous review by searching the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (2007, Issue 4), MEDLINE, EMBASE and CINAHL from 2001 to January 2008. We checked reference lists and sought advice from experts. No language restrictions were applied. Selection criteria Randomised controlled trials (RCTs) that compared centre-based cardiac rehabilitation (e.g. hospital, gymnasium, sports centre) with home-based programmes, in adults with myocardial infarction, angina, heart failure or who had undergone revascularisation. Data collection and analysis Studies were selected independently by two reviewers, and data extracted by a single reviewer and checked by a second one. Authors were contacted where possible to obtain missing information. Main results Twelve studies (1,938 participants) met the inclusion criteria. The majority of studies recruited a lower risk patient following an acute myocardial infarction (MI) and revascularisation. There was no difference in outcomes of home- versus centre-based cardiac rehabilitation in mortality risk ratio (RR) was 1.31 (95% confidence interval (C) 0.65 to 2.66), cardiac events, exercise capacity standardised mean difference (SMD) −0.11 (95% CI −0.35 to 0.13), as well

  13. Case-Based Tutoring from a Medical Knowledge Base

    PubMed Central

    Chin, Homer L.

    1988-01-01

    The past decade has seen the emergence of programs that make use of large knowledge bases to assist physicians in diagnosis within the general field of internal medicine. One such program, Internist-I, contains knowledge about over 600 diseases, covering a significant proportion of internal medicine. This paper describes the process of converting a subset of this knowledge base--in the area of cardiovascular diseases--into a probabilistic format, and the use of this resulting knowledge base to teach medical diagnostic knowledge. The system (called KBSimulator--for Knowledge-Based patient Simulator) generates simulated patient cases and uses these cases as a focal point from which to teach medical knowledge. It interacts with the student in a mixed-initiative fashion, presenting patients for the student to diagnose, and allowing the student to obtain further information on his/her own initiative in the context of that patient case. The system scores the student, and uses these scores to form a rudimentary model of the student. This resulting model of the student is then used to direct the generation of subsequent patient cases. This project demonstrates the feasibility of building an intelligent, flexible instructional system that uses a knowledge base constructed primarily for medical diagnosis.

  14. Skull base approaches in neurosurgery

    PubMed Central

    2010-01-01

    The skull base surgery is one of the most demanding surgeries. There are different structures that can be injured easily, by operating in the skull base. It is very important for the neurosurgeon to choose the right approach in order to reach the lesion without harming the other intact structures. Due to the pioneering work of Cushing, Hirsch, Yasargil, Krause, Dandy and other dedicated neurosurgeons, it is possible to address the tumor and other lesions in the anterior, the mid-line and the posterior cranial base. With the transsphenoidal, the frontolateral, the pterional and the lateral suboccipital approach nearly every region of the skull base is exposable. In the current state many different skull base approaches are described for various neurosurgical diseases during the last 20 years. The selection of an approach may differ from country to country, e.g., in the United States orbitozygomaticotomy for special lesions of the anterior skull base or petrosectomy for clivus meningiomas, are found more frequently than in Europe. The reason for writing the review was the question: Are there keyhole approaches with which someone can deal with a vast variety of lesions in the neurosurgical field? In my opinion the different surgical approaches mentioned above cover almost 95% of all skull base tumors and lesions. In the following text these approaches will be described. These approaches are: 1) pterional approach 2) frontolateral approach 3) transsphenoidal approach 4) suboccipital lateral approach These approaches can be extended and combined with each other. In the following we want to enhance this philosophy. PMID:20602753

  15. [Laser-based radiometric calibration].

    PubMed

    Li, Zhi-gang; Zheng, Yu-quan

    2014-12-01

    Increasingly higher demands are put forward to spectral radiometric calibration accuracy and the development of new tunable laser based spectral radiometric calibration technology is promoted, along with the development of studies of terrestrial remote sensing, aeronautical and astronautical remote sensing, plasma physics, quantitative spectroscopy, etc. Internationally a number of national metrology scientific research institutes have built tunable laser based spectral radiometric calibration facilities in succession, which are traceable to cryogenic radiometers and have low uncertainties for spectral responsivity calibration and characterization of detectors and remote sensing instruments in the UK, the USA, Germany, etc. Among them, the facility for spectral irradiance and radiance responsivity calibrations using uniform sources (SIRCCUS) at the National Institute of Standards and Technology (NIST) in the USA and the Tunable Lasers in Photometry (TULIP) facility at the Physikalisch-Technische Bundesanstalt (PTB) in Germany have more representatives. Compared with lamp-monochromator systems, laser based spectral radiometric calibrations have many advantages, such as narrow spectral bandwidth, high wavelength accuracy, low calibration uncertainty and so on for radiometric calibration applications. In this paper, the development of laser-based spectral radiometric calibration and structures and performances of laser-based radiometric calibration facilities represented by the National Physical Laboratory (NPL) in the UK, NIST and PTB are presented, technical advantages of laser-based spectral radiometric calibration are analyzed, and applications of this technology are further discussed. Laser-based spectral radiometric calibration facilities can be widely used in important system-level radiometric calibration measurements with high accuracy, including radiance temperature, radiance and irradiance calibrations for space remote sensing instruments, and promote the

  16. Antibacterial and antifungal metal based triazole Schiff bases.

    PubMed

    Chohan, Zahid H; Hanif, Muhammad

    2013-10-01

    A new series of four biologically active triazole derived Schiff base ligands (L(1)-L(4)) and their cobalt(II), nickel(II), copper(II) and zinc(II) complexes (1-16) have been synthesized and characterized. The ligands were prepared by the condensation reaction of 3-amino-5-methylthio-1H-1,2,4-triazole with chloro-, bromo- and nitro-substituted 2-hydroxybenzaldehyde in an equimolar ratio. The antibacterial and antifungal bioactivity data showed the metal(II) complexes to be more potent antibacterial and antifungal than the parent Schiff bases against one or more bacterial and fungal species.

  17. Photography-based image generator

    NASA Astrophysics Data System (ADS)

    Dalton, Nicholas M.; Deering, Charles S.

    1989-09-01

    A two-channel Photography Based Image Generator system was developed to drive the Helmet Mounted Laser Projector at the Naval Training System Center at Orlando, Florida. This projector is a two-channel system that displays a wide field-of-view color image with a high-resolution inset to efficiently match the pilot's visual capability. The image generator is a derivative of the LTV-developed visual system installed in the A-7E Weapon System Trainer at NAS Cecil Field. The Photography Based Image Generator is based on patented LTV technology for high resolution, multi-channel, real world visual simulation. Special provisions were developed for driving the NTSC-developed and patented Helmet Mounted Laser Projector. These include a special 1023-line raster format, an electronic image blending technique, spherical lens mapping for dome projection, a special computer interface for head/eye tracking and flight parameters, special software, and a number of data bases. Good gaze angle tracking is critical to the use of the NTSC projector in a flight simulation environment. The Photography Based Image Generator provides superior dynamic response by performing a relatively simple perspective transformation on stored, high-detail photography instead of generating this detail by "brute force" computer image generation methods. With this approach, high detail can be displayed and updated at the television field rate (60 Hz).

  18. Automated knowledge-base refinement

    NASA Technical Reports Server (NTRS)

    Mooney, Raymond J.

    1994-01-01

    Over the last several years, we have developed several systems for automatically refining incomplete and incorrect knowledge bases. These systems are given an imperfect rule base and a set of training examples and minimally modify the knowledge base to make it consistent with the examples. One of our most recent systems, FORTE, revises first-order Horn-clause knowledge bases. This system can be viewed as automatically debugging Prolog programs based on examples of correct and incorrect I/O pairs. In fact, we have already used the system to debug simple Prolog programs written by students in a programming language course. FORTE has also been used to automatically induce and revise qualitative models of several continuous dynamic devices from qualitative behavior traces. For example, it has been used to induce and revise a qualitative model of a portion of the Reaction Control System (RCS) of the NASA Space Shuttle. By fitting a correct model of this portion of the RCS to simulated qualitative data from a faulty system, FORTE was also able to correctly diagnose simple faults in this system.

  19. Summary of LOGDEX data base

    SciTech Connect

    Hill, T.; Sepehrnoori, K.

    1981-08-01

    A summary of LOGDEX, the digitized well log data base maintained by the Center for Energy Studies at The University of Texas at Austin is presented. These well logs were obtained from various oil companies and then converted from paper well logs to numeric information on magnetic computer tapes for input into the well log data base. This data base serves as a resource for application programs in the study of geopressured geothermal energy resources, for well logging research, and for geological research. Currently the location and scope of well log data that may be found within the LOGDEX data base are limited to wells along the Texas-Louisiana Gulf Coast that are known to have a potential as a geopressured geothermal energy resource. Additionally the location of these wells in that area is highly localized into areas that have been defined by Department of Energy researchers as having a high potential for geopressured geothermal energy. The LOGDEX data base currently contains data from more than 350 wells, representing more than 1600 logs and 16,600,000 curve feet of data. For quick reference to a given log, the summary listing has been indexed into seven divisions: well classification, location by county or parish, curve type, log type, operators, location by state, and well names. These indexes are arranged alphabetically and cross-referenced by page number.

  20. Imaging of skull base lesions.

    PubMed

    Kelly, Hillary R; Curtin, Hugh D

    2016-01-01

    Skull base imaging requires a thorough knowledge of the complex anatomy of this region, including the numerous fissures and foramina and the major neurovascular structures that traverse them. Computed tomography (CT) and magnetic resonance imaging (MRI) play complementary roles in imaging of the skull base. MR is the preferred modality for evaluation of the soft tissues, the cranial nerves, and the medullary spaces of bone, while CT is preferred for demonstrating thin cortical bone structure. The anatomic location and origin of a lesion as well as the specific CT and MR findings can often narrow the differential diagnosis to a short list of possibilities. However, the primary role of the imaging specialist in evaluating the skull base is usually to define the extent of the lesion and determine its relationship to vital neurovascular structures. Technologic advances in imaging and radiation therapy, as well as surgical technique, have allowed for more aggressive approaches and improved outcomes, further emphasizing the importance of precise preoperative mapping of skull base lesions via imaging. Tumors arising from and affecting the cranial nerves at the skull base are considered here.

  1. Directory Enabled Policy Based Networking

    SciTech Connect

    KELIIAA, CURTIS M.

    2001-10-01

    This report presents a discussion of directory-enabled policy-based networking with an emphasis on its role as the foundation for securely scalable enterprise networks. A directory service provides the object-oriented logical environment for interactive cyber-policy implementation. Cyber-policy implementation includes security, network management, operational process and quality of service policies. The leading network-technology vendors have invested in these technologies for secure universal connectivity that transverses Internet, extranet and intranet boundaries. Industry standards are established that provide the fundamental guidelines for directory deployment scalable to global networks. The integration of policy-based networking with directory-service technologies provides for intelligent management of the enterprise network environment as an end-to-end system of related clients, services and resources. This architecture allows logical policies to protect data, manage security and provision critical network services permitting a proactive defense-in-depth cyber-security posture. Enterprise networking imposes the consideration of supporting multiple computing platforms, sites and business-operation models. An industry-standards based approach combined with principled systems engineering in the deployment of these technologies allows these issues to be successfully addressed. This discussion is focused on a directory-based policy architecture for the heterogeneous enterprise network-computing environment and does not propose specific vendor solutions. This document is written to present practical design methodology and provide an understanding of the risks, complexities and most important, the benefits of directory-enabled policy-based networking.

  2. Secure Base Priming Diminishes Conflict-Based Anger and Anxiety

    PubMed Central

    Koren, Tamara; Bartholomew, Kim

    2016-01-01

    This study examines the impact of a visual representation of a secure base (i.e. a secure base prime) on attenuating experimentally produced anger and anxiety. Specifically, we examined the assuaging of negative emotions through exposure to an image of a mother-infant embrace or a heterosexual couple embracing. Subjects seated at a computer terminal rated their affect (Pre Affect) using the Affect Adjective Checklist (AAC) then listened to two sets of intense two person conflicts. After the first conflict exposure they rated affect again (Post 1 AAC). Following the second exposure they saw a blank screen (control condition), pictures of everyday objects (distraction condition) or a photo of two people embracing (Secure Base Prime condition). They then reported emotions using the Post 2 AAC. Compared to either control or distraction subjects, Secure Base Prime (SBP) subjects reported significantly less anger and anxiety. These results were then replicated using an internet sample with control, SBP and two new controls: Smiling Man (to control for expression of positive affect) and Cold Mother (an unsmiling mother with infant). The SBP amelioration of anger and anxiety was replicated with the internet sample. No control groups produced this effect, which was generated only by a combination of positive affect in a physically embracing dyad. The results are discussed in terms of attachment theory and research on spreading activation. PMID:27606897

  3. Mo-Si-B-Based Coatings for Ceramic Base Substrates

    NASA Technical Reports Server (NTRS)

    Perepezko, John Harry (Inventor); Sakidja, Ridwan (Inventor); Ritt, Patrick (Inventor)

    2015-01-01

    Alumina-containing coatings based on molybdenum (Mo), silicon (Si), and boron (B) ("MoSiB coatings") that form protective, oxidation-resistant scales on ceramic substrate at high temperatures are provided. The protective scales comprise an aluminoborosilicate glass, and may additionally contain molybdenum. Two-stage deposition methods for forming the coatings are also provided.

  4. Utilizing knowledge-base semantics in graph-based algorithms

    SciTech Connect

    Darwiche, A.

    1996-12-31

    Graph-based algorithms convert a knowledge base with a graph structure into one with a tree structure (a join-tree) and then apply tree-inference on the result. Nodes in the join-tree are cliques of variables and tree-inference is exponential in w*, the size of the maximal clique in the join-tree. A central property of join-trees that validates tree-inference is the running-intersection property: the intersection of any two cliques must belong to every clique on the path between them. We present two key results in connection to graph-based algorithms. First, we show that the running-intersection property, although sufficient, is not necessary for validating tree-inference. We present a weaker property for this purpose, called running-interaction, that depends on non-structural (semantical) properties of a knowledge base. We also present a linear algorithm that may reduce w* of a join-tree, possibly destroying its running-intersection property, while maintaining its running-interaction property and, hence, its validity for tree-inference. Second, we develop a simple algorithm for generating trees satisfying the running-interaction property. The algorithm bypasses triangulation (the standard technique for constructing join-trees) and does not construct a join-tree first. We show that the proposed algorithm may in some cases generate trees that are more efficient than those generated by modifying a join-tree.

  5. From evidence based bioethics to evidence based social policies

    PubMed Central

    2007-01-01

    In this issue, Norwegian authors demonstrate that causes of early expulsion out the workforce are rooted in childhood. They reconstruct individual biographies in administrative databases linked by an unique national identification number, looking forward 15 years in early adulthood and looking back 20 years till birth with close to negligible loss to follow up. Evidence based bioethics suggest that it is better to live in a country that allows reconstructing biographies in administrative databases then in countries that forbid access by restrictive legislation based on privacy considerations. The benefits of gained knowledge from existing and accessible information are tangible, particularly for the weak and the poor, while the harms of theoretical privacy invasion have not yet materialised. The study shows once again that disadvantage runs in families. Low parental education, parental disability and unstable marital unions predict early disability pensions and premature expulsion out gainful employment. The effect of low parental education is mediated by low education of the index person. However, in a feast of descriptive studies of socio-economic causes of ill health we still face a famine of evaluative intervention studies. An evidence based social policy should be based on effective interventions that are able to break the vicious circles of disability handed down from generation to generation. PMID:17657572

  6. Cereal based oral rehydration solutions.

    PubMed

    Kenya, P R; Odongo, H W; Oundo, G; Waswa, K; Muttunga, J; Molla, A M; Nath, S K; Molla, A; Greenough, W B; Juma, R

    1989-07-01

    A total of 257 boys (age range 4-55 months), who had acute diarrhoea with moderate to severe dehydration, were randomly assigned to treatment with either the World Health Organisation/United Nations Childrens Fund (WHO/Unicef) recommended oral rehydration solution or cereal based oral rehydration solution made either of maize, millet, sorghum, or rice. After the initial rehydration was achieved patients were offered traditional weaning foods. Treatment with oral rehydration solution continued until diarrhoea stopped. Accurate intake and output was maintained throughout the study period. Efficacy of the treatment was compared between the different treatment groups in terms of intake of the solution, stool output, duration of diarrhoea after admission, and weight gain after 24, 48, and 72 hours, and after resolution of diarrhoea. Results suggest that all the cereal based solutions were as effective as glucose based standard oral rehydration solution in the treatment of diarrhoea.

  7. Photoelectrochemical based direct conversion systems

    SciTech Connect

    Kocha, S.; Arent, D.; Peterson, M.

    1995-09-01

    The goal of this research is to develop a stable, cost effective, photoelectrochemical based system that will split water upon illumination, producing hydrogen and oxygen directly, using sunlight as the only energy input. This type of direct conversion system combines a photovoltaic material and an electrolyzer into a single monolithic device. We report on our studies of two multifunction multiphoton photoelectrochemical devices, one based on the ternary semiconductor gallium indium phosphide, (GaInP{sub 2}), and the other one based on amorphous silicon carbide. We also report on our studies of the solid state surface treatment of GaInP{sub 2} as well as our continuing effort to develop synthetic techniques for the attachment of transition metal complexes to the surface of semiconductor electrodes. All our surface studies are directed at controlling the interface energetics and forming stable catalytic surfaces.

  8. Factorization-based texture segmentation

    SciTech Connect

    Yuan, Jiangye; Wang, Deliang; Cheriyadat, Anil M.

    2015-06-17

    This study introduces a factorization-based approach that efficiently segments textured images. We use local spectral histograms as features, and construct an M × N feature matrix using M-dimensional feature vectors in an N-pixel image. Based on the observation that each feature can be approximated by a linear combination of several representative features, we factor the feature matrix into two matrices-one consisting of the representative features and the other containing the weights of representative features at each pixel used for linear combination. The factorization method is based on singular value decomposition and nonnegative matrix factorization. The method uses local spectral histograms to discriminate region appearances in a computationally efficient way and at the same time accurately localizes region boundaries. Finally, the experiments conducted on public segmentation data sets show the promise of this simple yet powerful approach.

  9. Brain plasticity-based therapeutics

    PubMed Central

    Merzenich, Michael M.; Van Vleet, Thomas M.; Nahum, Mor

    2014-01-01

    The primary objective of this review article is to summarize how the neuroscience of brain plasticity, exploiting new findings in fundamental, integrative and cognitive neuroscience, is changing the therapeutic landscape for professional communities addressing brain-based disorders and disease. After considering the neurological bases of training-driven neuroplasticity, we shall describe how this neuroscience-guided perspective distinguishes this new approach from (a) the more-behavioral, traditional clinical strategies of professional therapy practitioners, and (b) an even more widely applied pharmaceutical treatment model for neurological and psychiatric treatment domains. With that background, we shall argue that neuroplasticity-based treatments will be an important part of future best-treatment practices in neurological and psychiatric medicine. PMID:25018719

  10. Materials properties data base computerization

    NASA Technical Reports Server (NTRS)

    Baur, R. G.; Donthnier, M. L.; Moran, M. C.; Mortman, I.; Pinter, R. S.

    1984-01-01

    Material property data plays a key role in the design of jet engine components. Consistency, accuracy and efficient use of material property data is of prime importance to the engineering community. The system conception, development, implementation, and future plans for computer software that captures the Material Properties Handbook into a scientific data base are described. The engineering community is given access to raw data and property curves, display of multiple curves for material evaluation and selection, direct access by design analysis computer programs, display of the material specification, and a historical repository for the material evolution. The impact of this activity includes significant productivity gains and cost reductions; all users have access to the same information nd provides consistent, rapid response to the needs of the engineering community. Future plans include incorporating the materials properties data base into a network environment to access information from other data bases and download information to engineering work stations.

  11. CARS-based silicon photonics

    NASA Astrophysics Data System (ADS)

    Vermeulen, Nathalie; Debaes, Christof; Thienpont, Hugo

    2009-05-01

    In this invited paper, we will first discuss the recent research progress regarding silicon-on-insulator (SOI) Raman wavelength converters, the working principle of which is based on the four-wave mixing process of coherent anti-Stokes Raman scattering (CARS). Next, we will present our research results on other aspects of CARS in SOI waveguides. First, starting from the basic formalism for CARS we will show that, in contrast to what most scientists believe, CARS exchanges energy with the Raman medium in which it takes place and is even able to extract energy (i.e. extract phonons) from it. Furthermore, we will introduce a novel CARS-based approach to reduce the heat dissipation in Raman lasers due to the quantum defect between pump and lasing photons, and we will numerically demonstrate that with this "CARS-based heat mitigation technique" the quantum-defect heating in SOI waveguide Raman lasers could be reduced with as much as 35%.

  12. [Cell based therapy for COPD].

    PubMed

    Kubo, Hiroshi

    2007-04-01

    To develop a new cell based therapy for chronic obstructive pulmonary disease (COPD), we need to understand 1) the role of tissue-specific and bone marrow-derived stem cells, 2) extracellular matrix, and 3) growth factors. Recently, bronchioalveolar stem cells were identified in murine distal lungs. Impairment of these stem cells may cause improper lung repair after inflammation, resulting in pulmonary emphysema. Bone marrow-derived cells are necessary to repair injured lungs. However, the long term role of these cells is not understood yet. Although we need more careful analysis and additional experiments, growth factors, such as hepatocyte growth factor, are good candidates for the new cell based therapy for COPD. Lung was believed as a non-regenerative organ. Based on these recent reports about lung regeneration and stem cells, however, new strategies to treat COPD and a new point of view to understand the pathophysiology of COPD are rising.

  13. Metal-Based PSMA Radioligands.

    PubMed

    Gourni, Eleni; Henriksen, Gjermund

    2017-03-24

    Prostate cancer is one of the most common malignancies for which great progress has been made in identifying appropriate molecular targets that would enable efficient in vivo targeting for imaging and therapy. The type II integral membrane protein, prostate specific membrane antigen (PSMA) is overexpressed on prostate cancer cells in proportion to the stage and grade of the tumor progression, especially in androgen-independent, advanced and metastatic disease, rendering it a promising diagnostic and/or therapeutic target. From the perspective of nuclear medicine, PSMA-based radioligands may significantly impact the management of patients who suffer from prostate cancer. For that purpose, chelating-based PSMA-specific ligands have been labeled with various diagnostic and/or therapeutic radiometals for single-photon-emission tomography (SPECT), positron-emission-tomography (PET), radionuclide targeted therapy as well as intraoperative applications. This review focuses on the development and further applications of metal-based PSMA radioligands.

  14. School-based asthma programs.

    PubMed

    Bruzzese, Jean-Marie; Evans, David; Kattan, Meyer

    2009-08-01

    Asthma is prevalent in school-age children and contributes to school absenteeism and limitation of activity. There is a sizable literature on school-based interventions for asthma that attempt to identify children with asthma and improve outcomes. The purpose of this review is to describe and discuss limitations of screening tools and school-based asthma interventions. Identification of children with asthma may be appropriate in schools located in districts with a high prevalence of children experiencing significant morbidity and a high prevalence of undiagnosed asthma, provided there is access to high-quality asthma care. We review strategies for improving access to care, for teaching self-management skills in schools, and for improving school personnel management skills. Although studies indicate that school-based programs have the potential to improve outcomes, competing priorities in the educational system present challenges to their implementation and emphasize the need for practical, targeted, and cost-effective strategies.

  15. Plume base flow simulation technology

    NASA Technical Reports Server (NTRS)

    Roberts, B. B.; Wallace, R. O.; Sims, J. L.

    1983-01-01

    A combined analytical/empirical approach was studied in an effort to define the plume simulation parameters for base flow. For design purposes, rocket exhaust simulation (i.e., plume simulation) is determined by wind tunnel testing. Cold gas testing was concluded to be a cost and schedule effective data base of substantial scope. The results fell short of the target, although work conducted was conclusive and advanced the state of the art. Comparisons of wind tunnel predictions with Space Transportation System (STS) flight data showed considerable differences. However, a review of the technology program data base has yielded an additional parameter that may correlate flight and cold gas test data. Data from the plume technology program and the NASA test flights are presented to substantiate the proposed simulation parameters.

  16. Factorization-based texture segmentation

    DOE PAGES

    Yuan, Jiangye; Wang, Deliang; Cheriyadat, Anil M.

    2015-06-17

    This study introduces a factorization-based approach that efficiently segments textured images. We use local spectral histograms as features, and construct an M × N feature matrix using M-dimensional feature vectors in an N-pixel image. Based on the observation that each feature can be approximated by a linear combination of several representative features, we factor the feature matrix into two matrices-one consisting of the representative features and the other containing the weights of representative features at each pixel used for linear combination. The factorization method is based on singular value decomposition and nonnegative matrix factorization. The method uses local spectral histogramsmore » to discriminate region appearances in a computationally efficient way and at the same time accurately localizes region boundaries. Finally, the experiments conducted on public segmentation data sets show the promise of this simple yet powerful approach.« less

  17. Cellular-based preemption system

    NASA Technical Reports Server (NTRS)

    Bachelder, Aaron D. (Inventor)

    2011-01-01

    A cellular-based preemption system that uses existing cellular infrastructure to transmit preemption related data to allow safe passage of emergency vehicles through one or more intersections. A cellular unit in an emergency vehicle is used to generate position reports that are transmitted to the one or more intersections during an emergency response. Based on this position data, the one or more intersections calculate an estimated time of arrival (ETA) of the emergency vehicle, and transmit preemption commands to traffic signals at the intersections based on the calculated ETA. Additional techniques may be used for refining the position reports, ETA calculations, and the like. Such techniques include, without limitation, statistical preemption, map-matching, dead-reckoning, augmented navigation, and/or preemption optimization techniques, all of which are described in further detail in the above-referenced patent applications.

  18. Musculoskeletal colloquialisms based on weapons.

    PubMed

    Agrawal, Anuj

    2017-01-01

    Eponyms and colloquialisms are commonly used in orthopaedic literature and convey a great deal of information in a concise fashion. Several orthopaedic conditions have characteristic clinical or radiologic appearances, mimicking the appearance of certain arms or weapons. Most of these are easy to memorise and recognise, provided the orthopaedic surgeon is aware of the colloquialism and familiar with the appearance of the weapon on which it is based. Unfortunately, many such colloquialisms are based on traditional weapons no longer in current use, and their appearances are not familiar to most orthopaedists, creating confusion and difficulty in understanding them. In this paper, we have reviewed the musculoskeletal colloquialisms based on weapons, including a brief description of the weapon with illustrations, highlighting the importance of the colloquialism in diagnosis or treatment of musculoskeletal conditions.

  19. The initial lunar supply base

    NASA Technical Reports Server (NTRS)

    Criswell, D.

    1979-01-01

    The first lunar supply base should have a mass less than 1000 tons, be deployed by 24 persons in 4 months, and be maintained by 10 persons. Output could be expanded 20 times in 5 years to 600,000 tons/yr by a factor of 10 expansion of the area of the solar array on the lunar surface, using low power soil beneficiation, increasing the fleet of mining vehicles, and illuminating the base continuously at night with lunar orbiting mirrors. The space manufacturing facility (SMF) will supply most of the mass (solar cells and orbiting mirrors) necessary for expansion. Several devices and procedures are suggested for development which could further reduce the total mass necessary to transport to the Moon to establish the initial lunar supply base.

  20. Laser-powered lunar base

    NASA Technical Reports Server (NTRS)

    Costen, R.; Humes, Donald H.; Walker, G. H.; Williams, M. D.; Deyoung, Russell J.

    1989-01-01

    The objective was to compare a nuclear reactor-driven Sterling engine lunar base power source to a laser-to-electric converter with orbiting laser power station, each providing 1 MW of electricity to the lunar base. The comparison was made on the basis of total mass required in low-Earth-orbit for each system. This total mass includes transportation mass required to place systems in low-lunar orbit or on the lunar surface. The nuclear reactor with Sterling engines is considered the reference mission for lunar base power and is described first. The details of the laser-to-electric converter and mass are discussed. The next two solar-driven high-power laser concepts, the diode array laser or the iodine laser system, are discussed with associated masses in low-lunar-orbit. Finally, the payoff for laser-power beaming is summarized.

  1. Space construction base control system

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Aspects of an attitude control system were studied and developed for a large space base that is structurally flexible and whose mass properties change rather dramatically during its orbital lifetime. Topics of discussion include the following: (1) space base orbital pointing and maneuvering; (2) angular momentum sizing of actuators; (3) momentum desaturation selection and sizing; (4) multilevel control technique applied to configuration one; (5) one-dimensional model simulation; (6) N-body discrete coordinate simulation; (7) structural analysis math model formulation; and (8) discussion of control problems and control methods.

  2. Water based drilling mud additive

    SciTech Connect

    McCrary, J.L.

    1983-12-13

    A water based fluid additive useful in drilling mud used during drilling of an oil or gas well is disclosed, produced by reacting water at temperatures between 210/sup 0/-280/sup 0/ F. with a mixture comprising in percent by weight: gilsonite 25-30%, tannin 7-15%, lignite 25-35%, sulfonating compound 15-25%, water soluble base compound 5-15%, methylene-yielding compound 1-5%, and then removing substantially all of the remaining water to produce a dried product.

  3. Computer-Based Weather Research.

    DTIC Science & Technology

    1980-02-29

    F D-A994 020 SYSTEMS AND APPLZED SCIENCES CORP RIVERDALE MD FIG q/ COMPUTER BASED WEATHER RESEARCH.(U) FEB 80 A M GERLACH F19628-79-C-0033 Mrt F P0...AFGL-TR-80-0069 Na EIIIETEEII IBIBIIfIIIINI 0 Alan M4. Gerlach (ed.) I ~ stems and Applied Sciences Corporationl N~i eiworth Avenue I Riverdale...TITLE (and Si~bt,tle) 5 TYPE OF REPORT & PERIOD COVERED 7 cientific X’epaartVo. 2. COMPUTER-BASED WEATHER RESEARCH I Dee 78 - 3/’ Nov 79 \\ 7AUTHOR B ~MER

  4. Transistor-based interface circuitry

    DOEpatents

    Taubman, Matthew S.

    2007-02-13

    Among the embodiments of the present invention is an apparatus that includes a transistor, a servo device, and a current source. The servo device is operable to provide a common base mode of operation of the transistor by maintaining an approximately constant voltage level at the transistor base. The current source is operable to provide a bias current to the transistor. A first device provides an input signal to an electrical node positioned between the emitter of the transistor and the current source. A second device receives an output signal from the collector of the transistor.

  5. Transistor-based interface circuitry

    DOEpatents

    Taubman, Matthew S.

    2004-02-24

    Among the embodiments of the present invention is an apparatus that includes a transistor, a servo device, and a current source. The servo device is operable to provide a common base mode of operation of the transistor by maintaining an approximately constant voltage level at the transistor base. The current source is operable to provide a bias current to the transistor. A first device provides an input signal to an electrical node positioned between the emitter of the transistor and the current source. A second device receives an output signal from the collector of the transistor.

  6. Laser-based coatings removal

    SciTech Connect

    Freiwald, J.G.; Freiwald, D.A.

    1995-10-01

    Over the years as building and equipment surfaces became contaminated with low levels of uranium or plutonium dust, coats of paint were applied to stabilize the contaminants in place. Most of the earlier paint used was lead-based paint. More recently, various non-lead-based paints, such as two-part epoxy, are used. For D&D (decontamination and decommissioning), it is desirable to remove the paints or other coatings rather than having to tear down and dispose of the entire building. This report describes the use of pulse-repetetion laser systems for the removal of paints and coatings.

  7. Oil base drilling fluid composition

    SciTech Connect

    Patel, A.D.; Salandanan, C.

    1988-04-26

    This patent describes an improved oil-base drilling fluid composition characterized by thixotropic properties resulting in a yield point of from about 10 to about 75 comprising an oil-base continuous phase and a gelling composition. The gelling composition includes a latex material copolymerized with one or more functional monomers selected from the group consisting of: amides, amines, sulfonates, monocarboxylic acids, dicarboxylic acids and combinations thereof and wherein at least one of the one or more functional monomers is an amide selected from the group consisting of: acrylamide, N-methylolacrylamide, N-alkyl-acrylamide, vinylacetamide, vinylpyrrolidone, N-vinyl-N-methylacetamide, vinylformamide and combinations thereof.

  8. Case-based medical informatics

    PubMed Central

    Pantazi, Stefan V; Arocha, José F; Moehr, Jochen R

    2004-01-01

    Background The "applied" nature distinguishes applied sciences from theoretical sciences. To emphasize this distinction, we begin with a general, meta-level overview of the scientific endeavor. We introduce the knowledge spectrum and four interconnected modalities of knowledge. In addition to the traditional differentiation between implicit and explicit knowledge we outline the concepts of general and individual knowledge. We connect general knowledge with the "frame problem," a fundamental issue of artificial intelligence, and individual knowledge with another important paradigm of artificial intelligence, case-based reasoning, a method of individual knowledge processing that aims at solving new problems based on the solutions to similar past problems. We outline the fundamental differences between Medical Informatics and theoretical sciences and propose that Medical Informatics research should advance individual knowledge processing (case-based reasoning) and that natural language processing research is an important step towards this goal that may have ethical implications for patient-centered health medicine. Discussion We focus on fundamental aspects of decision-making, which connect human expertise with individual knowledge processing. We continue with a knowledge spectrum perspective on biomedical knowledge and conclude that case-based reasoning is the paradigm that can advance towards personalized healthcare and that can enable the education of patients and providers. We center the discussion on formal methods of knowledge representation around the frame problem. We propose a context-dependent view on the notion of "meaning" and advocate the need for case-based reasoning research and natural language processing. In the context of memory based knowledge processing, pattern recognition, comparison and analogy-making, we conclude that while humans seem to naturally support the case-based reasoning paradigm (memory of past experiences of problem-solving and

  9. Knowledge based jet engine diagnostics

    NASA Technical Reports Server (NTRS)

    Jellison, Timothy G.; Dehoff, Ronald L.

    1987-01-01

    A fielded expert system automates equipment fault isolation and recommends corrective maintenance action for Air Force jet engines. The knowledge based diagnostics tool was developed as an expert system interface to the Comprehensive Engine Management System, Increment IV (CEMS IV), the standard Air Force base level maintenance decision support system. XMAM (trademark), the Expert Maintenance Tool, automates procedures for troubleshooting equipment faults, provides a facility for interactive user training, and fits within a diagnostics information feedback loop to improve the troubleshooting and equipment maintenance processes. The application of expert diagnostics to the Air Force A-10A aircraft TF-34 engine equipped with the Turbine Engine Monitoring System (TEMS) is presented.

  10. Knowledge-based nursing diagnosis

    NASA Astrophysics Data System (ADS)

    Roy, Claudette; Hay, D. Robert

    1991-03-01

    Nursing diagnosis is an integral part of the nursing process and determines the interventions leading to outcomes for which the nurse is accountable. Diagnoses under the time constraints of modern nursing can benefit from a computer assist. A knowledge-based engineering approach was developed to address these problems. A number of problems were addressed during system design to make the system practical extended beyond capture of knowledge. The issues involved in implementing a professional knowledge base in a clinical setting are discussed. System functions, structure, interfaces, health care environment, and terminology and taxonomy are discussed. An integrated system concept from assessment through intervention and evaluation is outlined.

  11. ADS Based on Linear Accelerators

    NASA Astrophysics Data System (ADS)

    Pan, Weimin; Dai, Jianping

    An accelerator-driven system (ADS), which combines a particle accelerator with a subcritical core, is commonly regarded as a promising device for the transmutation of nuclear waste, as well as a potential scheme for thorium-based energy production. So far the predominant choice of the accelerator for ADS is a superconducting linear accelerator (linac). This article gives a brief overview of ADS based on linacs, including the motivation, principle, challenges and research activities around the world. The status and future plan of the Chinease ADS (C-ADS) project will be highlighted and discussed in depth as an example.

  12. Why internet-based education?

    PubMed Central

    Gernsbacher, Morton Ann

    2015-01-01

    This essay illustrates five ways that Internet-based higher education can capitalize on fundamental principles of learning. Internet-based education can enable better mastery through distributed (shorter, more frequent) practice rather than massed (longer, less frequent) practice; it can optimize performance because it allows students to learn at their peak time of their day; it can deepen memory because it requires cheat-proof assignments and tests; it can promote critical thinking because it necessitates intellectual winnowing and sifting; and it can enhance writing skills by requiring students to write frequently and for a broad audience. PMID:25653625

  13. Literature-Based Instruction: Reshaping the Curriculum.

    ERIC Educational Resources Information Center

    Raphael, Taffy E., Ed.; Au, Kathryn H., Ed.

    Making a case for the value of literature-based instruction, this book presents an overview of the extensive knowledge base supporting literature-based approaches to literacy instruction. It notes that literature-based instruction goes beyond simply changing the kinds of texts children read--also required in literature-based instruction are an…

  14. Risk-based decisionmaking (Panel)

    SciTech Connect

    Smith, T.H.

    1995-12-31

    By means of a panel discussion and extensive audience interaction, explore the current challenges and progress to date in applying risk considerations to decisionmaking related to low-level waste. This topic is especially timely because of the proposed legislation pertaining to risk-based decisionmaking and because of the increased emphasis placed on radiological performance assessments of low-level waste disposal.

  15. Data-Based Teacher Development.

    ERIC Educational Resources Information Center

    Borg, Simon

    1998-01-01

    Describes how data from English language teaching (ELT) classroom research can be exploited in teacher development activities. The contribution data-based activities can make to teacher development is outlined, and examples that illustrate the principles underlying their design are presented. A case is made for using such activities to facilitate…

  16. Watershed-based survey designs

    USGS Publications Warehouse

    Detenbeck, N.E.; Cincotta, D.; Denver, J.M.; Greenlee, S.K.; Olsen, A.R.; Pitchford, A.M.

    2005-01-01

    Watershed-based sampling design and assessment tools help serve the multiple goals for water quality monitoring required under the Clean Water Act, including assessment of regional conditions to meet Section 305(b), identification of impaired water bodies or watersheds to meet Section 303(d), and development of empirical relationships between causes or sources of impairment and biological responses. Creation of GIS databases for hydrography, hydrologically corrected digital elevation models, and hydrologic derivatives such as watershed boundaries and upstream–downstream topology of subcatchments would provide a consistent seamless nationwide framework for these designs. The elements of a watershed-based sample framework can be represented either as a continuous infinite set defined by points along a linear stream network, or as a discrete set of watershed polygons. Watershed-based designs can be developed with existing probabilistic survey methods, including the use of unequal probability weighting, stratification, and two-stage frames for sampling. Case studies for monitoring of Atlantic Coastal Plain streams, West Virginia wadeable streams, and coastal Oregon streams illustrate three different approaches for selecting sites for watershed-based survey designs.

  17. MTA Computer Based Evaluation System.

    ERIC Educational Resources Information Center

    Brenner, Lisa P.; And Others

    The MTA PLATO-based evaluation system, which has been implemented by a consortium of schools of medical technology, is designed to be general-purpose, modular, data-driven, and interactive, and to accommodate other national and local item banks. The system provides a comprehensive interactive item-banking system in conjunction with online student…

  18. WEB-WAP based telecare.

    PubMed Central

    DeLeo, Gianluca; Krishna, Santosh; Balas, E. Andrew; Maglaveras, Nicos; Boren, Suzanne Austin; Beltrame, Francesco; Fato, Marco

    2002-01-01

    We have developed two telecare applications based on mobile telephony (WAP) and WEB. The first can be used to request Basic Life Support (BLS) guidelines any time by using a WAP device and to teach people and non-professionals involved in health care emergency situations. The second is a WEB-WAP based tool for medical data retrieval and at-home health care monitoring of chronically ill patients with congestive heart failure (CHF) or diabetes. Medical education content related to these diseases is available on the WEB and on the WAP device. The WAP application uses the features found in the last generation of mobile phones such as better multimedia information presentations, better interactivity capabilities, and enhanced ease of use. Based on these two applications, a promising platform is offered for developing applications in health care, home care, medical monitoring and health education ensuring continuity of care. In the paper we present the preliminary results of a pilot test at Thessaloniki University (Greece) where the WEB-WAP based tool is used to monitor patients with diabetes or CHF. PMID:12463815

  19. Problem Based Learning: Mystery Disease.

    ERIC Educational Resources Information Center

    Bohland, Mark A.

    This guide features a problem-based learning (PBL) unit specifically designed for student-centered learning of new and meaningful content on diseases. Students grapple with a complex and changing problem that requires higher level thinking skills in an environment in which students work both individually and in collaboration with others. Includes…

  20. Task-Based Writing Instruction

    ERIC Educational Resources Information Center

    Bantis, Alexandros

    2010-01-01

    The purpose of this study was to investigate the impact of task-based writing instruction, a communicative language-teaching method, on second language acquisition and differentiation of instruction for English language learners during the independent work time instructional component of the Open Court Reading program. Through student-teacher…

  1. Competency Based Refresher Nurse Curriculum.

    ERIC Educational Resources Information Center

    Lombardo, Mary C.

    This competency-based course is designed to update the skills and knowledge of inactive nurses desiring to return to active practice. Focus of the course is on organizing and managing patient care using the nursing process; performing nursing procedures, including medication administration; and reintegrating oneself into the professional…

  2. RF MEMS Based Reconfigurable Antennas

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.

    2004-01-01

    The presentation will first of all address the advantages of RF MEMS circuit in antenna applications and also the need for electronically reconfigurable antennas. Next, discuss some of the recent examples of RF MEMS based reconfigurable microstrip antennas. Finally, conclude the talk with a summary of MEMS antenna performance.

  3. Mesoporous Silicon-Based Anodes

    NASA Technical Reports Server (NTRS)

    Peramunage, Dharmasena

    2015-01-01

    For high-capacity, high-performance lithium-ion batteries. A new high-capacity anode composite based on mesoporous silicon is being developed. With a structure that resembles a pseudo one-dimensional phase, the active anode material will accommodate significant volume changes expected upon alloying and dealloying with lithium (Li).

  4. Computer Based Virtual Field Trips.

    ERIC Educational Resources Information Center

    Clark, Kenneth F.; Hosticka, Alice; Schriver, Martha; Bedell, Jackie

    This paper discusses computer based virtual field trips that use technologies commonly found in public schools in the United States. The discussion focuses on the advantages of both using and creating these field trips for an instructional situation. A virtual field trip to Cumberland Island National Seashore, St. Marys, Georgia is used as a point…

  5. Results of Computer Based Training.

    ERIC Educational Resources Information Center

    1978

    This report compares the projected savings of using computer based training to conduct training for newly hired pilots to the results of that application. New Hire training, one of a number of programs conducted continuously at the United Airline Flight Operations Training Center, is designed to assure that any newly hired pilot will be able to…

  6. Budgeting Based on Student Needs

    ERIC Educational Resources Information Center

    Willis, Jason; Hill, Matt

    2011-01-01

    School finance reform has become a key component for transforming public schools in the United States. Over the last decade, a growing number of districts have turned to an approach known by different names--student-based budgeting, weighted student funding and fair student funding, among others--in which budgets are allocated to schools in…

  7. Phonetics Information Base and Lexicon

    ERIC Educational Resources Information Center

    Moran, Steven Paul

    2012-01-01

    In this dissertation, I investigate the linguistic and technological challenges involved in creating a cross-linguistic data set to undertake phonological typology. I then address the question of whether more sophisticated, knowledge-based approaches to data modeling, coupled with a broad cross-linguistic data set, can extend previous typological…

  8. Colour Mixing Based on Daylight

    ERIC Educational Resources Information Center

    Meyn, Jan-Peter

    2008-01-01

    Colour science is based on the sensation of monochromatic light. In contrast to that, surface colours are caused by reflection of wide sections of the daylight spectrum. Non-spectral colours like magenta and purple appear homologous to colours with spectral hue, if the approach of mixing monochromatic light is abandoned. It is shown that a large…

  9. School-Based Health Centers

    MedlinePlus

    ... Safety Doctors & Hospitals Q&A Recipes En Español Teachers - Looking for Health Lessons? Visit KidsHealth in the ... has a health center by contacting your child's teacher or the school office. Most school-based health ...

  10. Mars base technology program overview

    NASA Technical Reports Server (NTRS)

    Chu, Chneg-Chih; Hayati, Samad A.; Udomkesmalee, Suraphol

    2005-01-01

    In this paper, we present an overview of the current technology portfolio for Mars Base Technology Program. Brief descriptions of the awarded technologies and the high-priority areas in both NRAs are provided to show the current focus of MTP. We also present the approach that MTP uses to evaluate technology maturity for each of the technology tasks.

  11. DOUBLE-BASE BINDER IMPROVEMENT.

    DTIC Science & Technology

    A base grain CMDB propellant was prepared successfully using a casting solvent (TEGDN/TMETN mixture) that was high in TEGDN content. The mechanical...means to improve the mechanical properties of slurry casts CMDB propellants, efforts were concerned with structure and properties comparison of various

  12. Population Education: A Knowledge Base.

    ERIC Educational Resources Information Center

    Jacobson, Willard J.

    To aid junior high and high school educators and curriculum planners as they develop population education programs, the book provides an overview of the population education knowledge base. In addition, it suggests learning activities, discussion questions, and background information which can be integrated into courses dealing with population,…

  13. Graphite-based photovoltaic cells

    DOEpatents

    Lagally, Max; Liu, Feng

    2010-12-28

    The present invention uses lithographically patterned graphite stacks as the basic building elements of an efficient and economical photovoltaic cell. The basic design of the graphite-based photovoltaic cells includes a plurality of spatially separated graphite stacks, each comprising a plurality of vertically stacked, semiconducting graphene sheets (carbon nanoribbons) bridging electrically conductive contacts.

  14. Watershed-based survey designs.

    PubMed

    Detenbeck, Naomi E; Cincotta, Dan; Denver, Judith M; Greenlee, Susan K; Olsen, Anthony R; Pitchford, Ann M

    2005-04-01

    Watershed-based sampling design and assessment tools help serve the multiple goals for water quality monitoring required under the Clean Water Act, including assessment of regional conditions to meet Section 305(b), identification of impaired water bodies or watersheds to meet Section 303(d), and development of empirical relationships between causes or sources of impairment and biological responses. Creation of GIS databases for hydrography, hydrologically corrected digital elevation models, and hydrologic derivatives such as watershed boundaries and upstream-downstream topology of subcatchments would provide a consistent seamless nationwide framework for these designs. The elements of a watershed-based sample framework can be represented either as a continuous infinite set defined by points along a linear stream network, or as a discrete set of watershed polygons. Watershed-based designs can be developed with existing probabilistic survey methods, including the use of unequal probability weighting, stratification, and two-stage frames for sampling. Case studies for monitoring of Atlantic Coastal Plain streams, West Virginia wadeable streams, and coastal Oregon streams illustrate three different approaches for selecting sites for watershed-based survey designs.

  15. Water-based cleaning fundamentals

    SciTech Connect

    Harding, W.B.

    1991-12-01

    A basic description of water-based alkaline cleaning is presented, The nature of soils is described. The compositions of conventional cleaning compounds are given with descriptions of the functions of the ingredients. The mechanisms by which soil is removed are explained. The degrees of cleanliness required, along with the influence of the material being cleaned, are discussed. Tests for cleanliness are described.

  16. Comparison of Document Data Bases

    ERIC Educational Resources Information Center

    Schipma, Peter B.; And Others

    This paper presents a detailed analysis of the content and format of seven machine-readable bibliographic data bases: Chemical Abstracts Service Condensates, Chemical and Biological Activities, and Polymer Science and Technology, Biosciences Information Service's BA Previews including Biological Abstracts and BioResearch Index, Institute for…

  17. Project-Based Module Development.

    ERIC Educational Resources Information Center

    Meel, R. M. van

    A project management design for modularizing higher education at open universities was developed and tested. Literature in the fields of project management and development of modular curriculum materials was reviewed and used as a basis for developing a project-based approach to the process of developing modules for self-instruction. According to…

  18. Learning-Based Curriculum Development

    ERIC Educational Resources Information Center

    Nygaard, Claus; Hojlt, Thomas; Hermansen, Mads

    2008-01-01

    This article is written to inspire curriculum developers to centre their efforts on the learning processes of students. It presents a learning-based paradigm for higher education and demonstrates the close relationship between curriculum development and students' learning processes. The article has three sections: Section "The role of higher…

  19. Computer-Based Concept Mapping.

    ERIC Educational Resources Information Center

    Fisher, K. M.; And Others

    1990-01-01

    Described is a computer-based tool, SemNet, which can be used by good and poor students to facilitate, extend, and polish their learning skills. Emphasized are skills associated with meaningful or deep-level learning. The components, use, and theoretical background of the software are discussed. (CW)

  20. Design-Based Implementation Research

    ERIC Educational Resources Information Center

    LeMahieu, Paul G.; Nordstrum, Lee E.; Potvin, Ashley Seidel

    2017-01-01

    Purpose: This paper is second of seven in this volume elaborating different approaches to quality improvement in education. It delineates a methodology called design-based implementation research (DBIR). The approach used in this paper is aimed at iteratively improving the quality of classroom teaching and learning practices in defined problem…

  1. ANN - based distribution system reconfiguration

    SciTech Connect

    Momoh, J.A.; Wang, Yanchun; Rizy, D.T.

    1997-08-01

    This paper describes an Artificial Neural Network (ANN) - based distribution system reconfiguration scheme to reduce system loss. The ANN is trained for different load levels and different network topologies. The proposed scheme has been tested using a 38 - bus distribution system. The results are very promising.

  2. WATERSHED-BASED SURVEY DESIGNS

    EPA Science Inventory

    Water-based sampling design and assessment tools help serve the multiple goals for water quality monitoring required under the Clean Water Act, including assessment of regional conditions to meet Section 305(b), identification if impaired water bodies or watersheds to meet Sectio...

  3. Responsive starch-based materials

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Starch, a low-cost, annually renewable resource, is naturally hydrophilic and its properties change with relative humidity. Starch’s hygroscopic nature can be used to develop materials which change shape or volume in response to environmental changes (e.g. humidity). For example, starch-based graf...

  4. Network-Based Management Procedures.

    ERIC Educational Resources Information Center

    Buckner, Allen L.

    Network-based management procedures serve as valuable aids in organizational management, achievement of objectives, problem solving, and decisionmaking. Network techniques especially applicable to educational management systems are the program evaluation and review technique (PERT) and the critical path method (CPM). Other network charting…

  5. Model-Based Safety Analysis

    NASA Technical Reports Server (NTRS)

    Joshi, Anjali; Heimdahl, Mats P. E.; Miller, Steven P.; Whalen, Mike W.

    2006-01-01

    System safety analysis techniques are well established and are used extensively during the design of safety-critical systems. Despite this, most of the techniques are highly subjective and dependent on the skill of the practitioner. Since these analyses are usually based on an informal system model, it is unlikely that they will be complete, consistent, and error free. In fact, the lack of precise models of the system architecture and its failure modes often forces the safety analysts to devote much of their effort to gathering architectural details about the system behavior from several sources and embedding this information in the safety artifacts such as the fault trees. This report describes Model-Based Safety Analysis, an approach in which the system and safety engineers share a common system model created using a model-based development process. By extending the system model with a fault model as well as relevant portions of the physical system to be controlled, automated support can be provided for much of the safety analysis. We believe that by using a common model for both system and safety engineering and automating parts of the safety analysis, we can both reduce the cost and improve the quality of the safety analysis. Here we present our vision of model-based safety analysis and discuss the advantages and challenges in making this approach practical.

  6. Competency-Based Behavioral Interviewing

    ERIC Educational Resources Information Center

    Garrigues, Sarah M.

    2012-01-01

    Directors too often rely primarily on their hunches to guide them in employee selection. But what if their hunches are only 30 percent correct? Potentially, one bad hire could be responsible for a noticeable decrease in enrollment and, as a result, the school's net revenue. In this article, the author discusses the Competency-Based Behavioral…

  7. Lunar regolith at Tranquillity Base

    USGS Publications Warehouse

    Shoemaker, E.M.; Hait, M.H.; Swann, G.A.; Schleicher, D.L.; Dahlem, D.H.; Schaber, G.G.; Sutton, R.L.

    1970-01-01

    The regolith at Tranquillity Base is a layer of fragmental debris that ranges in thickness from about 3 to 6 meters. The thickness of the regolith and the exposure histories of its constituent fragments can be related, by means of a relatively simple model, to the observed crater distribution.

  8. Lunar regolith at tranquillity base.

    PubMed

    Shoemaker, E M; Hait, M H; Swann, G A; Schleicher, D L; Dahlem, D H; Schaber, G G; Sutton, R L

    1970-01-30

    The regolith at Tranquillity Base is a layer of fragmental debris that ranges in thickness from about 3 to 6 meters. The thickness of the regolith and the exposure histories of its constituent fragments can be related, by means of a relatively simple model, to the observed crater distribution.

  9. Ground-based IRCM testing

    NASA Astrophysics Data System (ADS)

    Greer, Derek; Owen, Mark

    2010-04-01

    Recent advances in the ability to perform comprehensive ground based Infrared Countermeasure (IRCM) testing have the capability to fill the Test and Evaluation (T&E) gaps for existing and future weapons system acquisition. IRCM testing has historically been dominated and in a manner limited by expensive live fire testing requirements. While live fire testing is a vital part of IRCM T&E, next generation technological developments now enable closed-loop, ground-based IRCM testing to provide valuable complementary test data at a much lower cost. The high cost and limited assets that have prevented live fire and flight testing from providing a thorough hardware based data set required for previous T&E analysis is no longer an issue. In the past, traditional physics based digital system model (DSM) analysis has been utilized to augment the IRCM data sets to make them statistically significant. While DSM is a useful tool in the development of IRCM systems, the newly developed installed system testing utilizing a hardware-in-the-loop construct provides for an enhanced level of fidelity and assurance that the systems will meet the warfighter's needs. The goal of the newly developed test technologies is to develop a statistical significant data set utilizing hardware-in-the-loop at a significantly lower cost than historical methods.

  10. Maintaining COTS-Based Systems

    DTIC Science & Technology

    2000-12-01

    12-1 Maintaining COTS-Based Systems Dr. Mark R. Vigder John Dean National Research Council of Canada Institute for Information Technology Ottawa...evluton destifyng cand s yste dff uresamng sets ongoingoperato n.ts devhoisg Configuration magement Tracking versions of different COTS products

  11. Competency-Based Horticulture: Floriculture.

    ERIC Educational Resources Information Center

    College of DuPage, Glen Ellyn, IL.

    This competency-based horticulture curriculum guide is designed to provide secondary and postsecondary horticulture teachers with a task-oriented program in floriculture. It contains a master resource list, a listing of floriculture resources available from various states, and 89 competency task sheets organized into nine competency areas. These…

  12. School Centered Evidence Based Accountability

    ERIC Educational Resources Information Center

    Milligan, Charles

    2015-01-01

    Achievement scores drive much of the effort in today's accountability system, however, there is much more that occurs in every school, every day. School Centered Evidence Based Accountability can be used from micro to macro giving School Boards and Administration a process for monitoring the results of the entire school operation effectively and…

  13. Competency-Based General Education.

    ERIC Educational Resources Information Center

    Hunter, Walter E.

    1979-01-01

    Presents arguments in favor of competency-based general education within the context of a program developed at Central Technical Community College (Nebraska) which utilizes an open entry, open exit approach for all programs. Outlines suggested competencies in the areas of communications and oral communications. (MB)

  14. Biomaterials in skull base surgery

    PubMed Central

    Maier, Wolfgang

    2011-01-01

    Reconstruction materials and techniques for the base of the skull have undergone rapid developments and differentiation in recent years. While mostly autotransplants, collagens or resorbable alloplastic materials are preferred for duraplasties, pronounced organ-specific differences can be observed in the reconstruction of hard tissues. The use of polymethylmethacryl bone cement, once wide-spread, has decreased greatly due to the release of toxic monomers. Bony autotransplants are still used primarily for smaller skull-base defects, intraoperatively formable titanium nets may be also used for larger fronto- or laterobasal reconstructions of bony defects. Defects in visible areas are increasingly closed with preformed titanium or ceramic implants, which are planned and fitted to the individual patient using preoperative CT imaging. At the skull base, this applies especially to reconstructions of the frontal sinus. For extensive reconstructions of the orbita, titanium nets and non-resorbable plastics have proven valuable; in closing smaller defects especially of the orbital floor, resorbable implants based on Polyglactin 901 are also used. PMID:22073100

  15. Data base management systems activities

    NASA Technical Reports Server (NTRS)

    1983-01-01

    The Data Management System-1100 is designed to operate in conjunction with the UNIVAC 1100 Series Operating System on any 1100 Series computer. DMS-1100 is divided into the following four major software components: (1) Data Definition Languages (DDL); (2) Data Management Routine (DMR); (3) Data Manipulation Languages (DML); and (4) Data Base Utilities (DBU). These software components are described in detail.

  16. Epistemology of knowledge based simulation

    SciTech Connect

    Reddy, R.

    1987-04-01

    Combining artificial intelligence concepts, with traditional simulation methodologies yields a powerful design support tool known as knowledge based simulation. This approach turns a descriptive simulation tool into a prescriptive tool, one which recommends specific goals. Much work in the area of general goal processing and explanation of recommendations remains to be done.

  17. Exemplary Web-Based Schools

    ERIC Educational Resources Information Center

    Milone, Michael

    2005-01-01

    Exemplary Web-based schools are as different as they are similar. The schools featured in this section have applied technology in unique ways to meet the needs of their students. Five examples are cited across the U.S.: Lemon Grove School District, Lemon Grove, California; Virginia Beach City Public Schools, Virginia Beach, Virginia; Carlsbad…

  18. Residue-based scattering factors.

    PubMed

    Xu, Hongliang

    2016-11-01

    A glob is defined as a group of atoms in the crystal which can be chosen in various ways. Globs themselves can be used as scattering elements in the theory of structure determination, just as atoms are used at present. In this paper, amino-acid residues are chosen to form globs and empirical formulas for residue-based scattering factors have been developed.

  19. Indigenous Community-Based Education.

    ERIC Educational Resources Information Center

    May, Stephen, Ed.

    After a long history as a tool of forced assimilation of indigenous populations, education is now a key arena in which indigenous peoples can reclaim and revalue their languages and cultures and thereby improve the academic success of indigenous students. Community-based education offers a means by which indigenous peoples can regain a measure of…

  20. Gears Based on Carbon Nanotubes

    NASA Technical Reports Server (NTRS)

    Jaffe, Richard; Han, Jie; Globus, Al; Deardorff, Glenn

    2005-01-01

    Gears based on carbon nanotubes (see figure) have been proposed as components of an emerging generation of molecular- scale machines and sensors. In comparison with previously proposed nanogears based on diamondoid and fullerene molecules, the nanotube-based gears would have simpler structures and are more likely to be realizable by practical fabrication processes. The impetus for the practical development of carbon-nanotube- based gears arises, in part, from rapid recent progress in the fabrication of carbon nanotubes with prescribed diameters, lengths, chiralities, and numbers of concentric shells. The shafts of the proposed gears would be made from multiwalled carbon nanotubes. The gear teeth would be rigid molecules (typically, benzyne molecules), bonded to the nanotube shafts at atomically precise positions. For fabrication, it may be possible to position the molecular teeth by use of scanning tunneling microscopy (STM) or other related techniques. The capability to position individual organic molecules at room temperature by use of an STM tip has already been demonstrated. Routes to the chemical synthesis of carbon-nanotube-based gears are also under investigation. Chemical and physical aspects of the synthesis of molecular scale gears based on carbon nanotubes and related molecules, and dynamical properties of nanotube- based gears, have been investigated by computational simulations using established methods of quantum chemistry and molecular dynamics. Several particularly interesting and useful conclusions have been drawn from the dynamical simulations performed thus far: The forces acting on the gears would be more sensitive to local molecular motions than to gross mechanical motions of the overall gears. Although no breakage of teeth or of chemical bonds is expected at temperatures up to at least 3,000 K, the gears would not work well at temperatures above a critical range from about 600 to about 1,000 K. Gear temperature could probably be controlled by