976 resultados para QUINONE POOL


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Despite the global oceanic distribution and recognized biogeochemical impact of coccolithoviruses (EhV), their diversity remains poorly understood. Here we employed a metagenomic approach to study the occurrence and progression of natural EhV community genomic variability. Analysis of EhV metagenomes from the early and late stages of an induced bloom led to three main discoveries. First, we observed resilient and specific genomic signatures in the EhV community associated with the Norwegian coast, which reinforce the existence of limitations to the capacity of dispersal and genomic exchange among EhV populations. Second, we identified a hyper-variable region (approximately 21 kbp long) in the coccolithovirus genome. Third, we observed a clear trend for EhV relative amino-acid diversity to reduce from early to late stages of the bloom. This study validated two new methodological combinations, and proved very useful in the discovery of new genomic features associated with coccolithovirus natural communities.

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Despite the global oceanic distribution and recognised biogeochemical impact of coccolithoviruses (EhV), their diversity remains poorly understood. Here we employed a metagenomic approach to study the occurrence and progression of natural EhV community genomic variability. Analysis of EhV metagenomes from the early and late stages of an induced bloom led to three main discoveries. First, we observed resilient and specific genomic signatures in the EhV community associated with the Norwegian coast, which reinforce the existence of limitations to the capacity of dispersal and genomic exchange among EhV populations. Second, we identified a hyper-variable region (approximately 21kbp long) in the coccolithovirus genome. Third, we observed a clear trend for EhV relative amino-acid diversity to reduce from early to late stages of the bloom. This study validated two new methodological combinations, and proved very useful in the discovery of new genomic features associated with coccolithovirus natural communities.

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. Knight, David W.; Lewis, Neil; Share, Andrew C.; Haigh, David. Chem. Dept., Univ. of Nottingham, Nottingham, UK. Tetrahedron: Asymmetry (1993), 4(4), 625-8. CODEN: TASYE3 ISSN: 0957-4166. Journal written in English. CAN 120:54423 AN 1994:54423 CAPLUS (Copyright (C) 2009 ACS on SciFinder (R)) Abstract Redn. of the keto-piperidinecarboxylates I and II with fermenting bakers' yeast produced the corresponding hydroxy-esters III and IV in good yields with >99% diastereomeric excess and >93% enantiomeric excess in both cases.

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Knight, David W.; Lewis, Neil; Share, Andrew C.; Haigh, David. Chemistry Department, University of Nottingham, Nottingham, UK. Journal of the Chemical Society, Perkin Transactions 1: Organic and Bio-Organic Chemistry (1998), (22), 3673-3684. Publisher: Royal Society of Chemistry, CODEN: JCPRB4 ISSN: 0300-922X. Journal written in English. CAN 130:153545 AN 1998:715806 CAPLUS (Copyright (C) 2009 ACS on SciFinder (R)) Abstract Redn. of the piperidine keto esters, e.g., I, using fermenting bakers' yeast provides high yields of the corresponding hydroxy esters, e.g., II, exclusively as the cis-diastereoisomers and with good levels (?80%) of enantiomeric enrichment. The relative stereochemistries of the products were deduced from NMR data while the abs. configurations were detd. by degrdn. to known piperidinemethanol derivs. or, in the case of hydroxy ester III, by homologation to (R)-3-quinuclidinol IV.

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Arsenic (As) contamination of paddy soils threatens rice cultivation and the health of populations relying on rice as a staple crop. In the present study, isotopic dilution techniques were used to determine the chemically labile (E value) and phytoavailable (L value) pools of As in a range of paddy soils from Bangladesh, India, and China and two arable soils from the UK varying in the degree and sources of As contamination. The E value accounted for 6.2-21.4% of the total As, suggesting that a large proportion of soil As is chemically nonlabile. L values measured with rice grown under anaerobic conditions were generally larger than those under aerobic conditions, indicating increased potentially phytoavailable pool of As in flooded soils. In an incubation study, As was mobilized into soil pore water mainly as arsenite under flooded conditions, with Bangladeshi soils contaminated by irrigation of groundwater showing a greater potential of As mobilization than other soils. Arsenic mobilization was best predicted by phosphate-extractable As in the soils.

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Purpose: The role of genetic susceptibility to esophageal adenocarcinorna and its precursor lesion Barrett esophagus has not been fully elucidated. This study investigated the effect of polymorphisms in the manganese superoxide dismutase (MnSOD) and NAD(P)H:quinone oxicloreductase 1 (NQO1) genes in modulating the risk of developing Barrett esophagus or esophageal adenocarcinoma. Methods: A total of 584 patients (146 esophagitis, 200 Barrett esophagus, 144 esophageal adenocarcinoma, and 94 controls) were genotyped for the MnSOD C14T and NQO1 C609T polymorphisms using polymerase chain reaction and restriction fragment length polymorphism analysis. Results: The NQO1 TT genotype was less common in Barrett esophagus (2.0%) and esophageal adenocarcinoma (1.4%) patients, compared with both esophagitis patients (7.6%) and controls (5.4%). After adjustment for sex, age, body mass index, reflux symptoms, and smoking status, patients with the homozygous TT genotype had a 4.5-fold decreased risk of developing Barrett esophagus (odds ratio = 0.22, 95% confidence interval = 0.07-0.76, P = 0.01) and a 6.2-fold decreased risk of esophageal adenocarcinorna (odds ratio = 0.16, 95% confidence intervals = 0.03-0.94, P = 0.04) compared with individuals with the TC and CC genotypes. No significant differences between groups were observed for the MnSOD polymorphism (P = 0.289). Conclusions: Overall, the results of this study suggest that the NQO1 TT genotype may offer protection from reflux complications such as Barrett esophagus and esophageal adenocarcinoma.

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There are two common forms of NRH-quinone oxidoreductase 2 (NQO2) in the human population resulting from SNP rs1143684. One has phenylalanine at position 47 (NQO2-F47) and the other leucine (NQO2-L47). Using recombinant proteins, we show that these variants have similar steady state kinetic parameters, although NQO2-L47 has a slightly lower specificity constant. NQO2-L47 is less stable towards proteolytic digestion and thermal denaturation than NQO2-F47. Both forms are inhibited by resveratrol, but NQO2-F47 shows negative cooperativity with this inhibitor. Thus these data demonstrate, for the first time, clear biochemical differences between the variants which help explain previous biomedical and epidemiological findings. © 2014 Federation of European Biochemical Societies.

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The proliferation of media services enabled by digital technologies poses a serious challenge to public service broadcasting rationales based on media scarcity. Looking to the past and future, we articulate an important role that the Australian Broadcasting Corporation (ABC) might play in the digital age. We argue that historically the ABC has acted beyond its institutional broadcasting remit to facilitate cultural development and, drawing on the example of Pool (an online community of creative practitioners established and maintained by the ABC), point to a key role it might play in fostering network innovation in what are now conceptualised as the creative industries.