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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 56 (2000), S. 689-692 
    ISSN: 1432-1041
    Schlagwort(e): N-acetyltransferase Chinese women Caffeine metabolites
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Abstract. Objective: The acetylation polymorphism is a common inherited variation in human drug and carcinogen metabolism. Because N-acetyltransferase (NAT2) is important for the detoxification and/or bioactivation of drugs and carcinogens, this polymorphism has important implications in therapeutics and cancer susceptibility. A high correlation between acetylation phenotype and genotype has been demonstrated in several studies. However, no such data exist for Chinese females. The aim of the present study was to compare acetylation phenotype with NAT2 genotype in a population of primarily non-smoking Chinese females. Methods: In the present study, the correlation between N-acetyltransferase activity and NAT2 genotype was evaluated in 103 unrelated Chinese female controls derived from a hospital-based case-control study of lung cancer in Singapore. Acetylation phenotype and genotype were respectively determined using caffeine and an allele-specific polymerase chain reaction (PCR). Results: The proportions of rapid and slow phenotypes were 78% and 22%, respectively, while the distribution of rapid (heterozygotes and homozygotes combined) and slow acetylator genotypes was 76% and 24%, respectively. The distribution of the various NAT2 genotypes did not differ significantly (X 2=1.45, P〉0.05) from that predicted by the Hardy-Weinberg Law. All slow acetylators were accurately predicted (100%), whereas 2 of 80 rapid acetylators were erroneously predicted as slow (2.5%). The overall prediction rate of the PCR-based test for the acetylation phenotype was at 98.1% in our Chinese population. Conclusion: Our results suggest that genotyping with PCR may well become the preferred method for the determination of acetylation polymorphism in epidemiological studies in this Asian population.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    s.l. ; Stafa-Zurich, Switzerland
    Advances in science and technology Vol. 48 (Oct. 2006), p. 24-30 
    ISSN: 1662-0356
    Quelle: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Thema: Allgemeine Naturwissenschaft , Technik allgemein
    Notizen: In this paper, porous carbon was made from biomass derived carbonaceous mesophaseand carbonaceous fillers, and further applied as the substrate for CVD grow of nano carbonmaterials. With the assistance of microwave plasma, the acetone gas was decomposed into carbonand grew on the surface of the porous carbon, which produce ballas diamonds, carbon tubes, nets,petal, and other structures
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    s.l. ; Stafa-Zurich, Switzerland
    Advances in science and technology Vol. 48 (Oct. 2006), p. 169-173 
    ISSN: 1662-0356
    Quelle: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Thema: Allgemeine Naturwissenschaft , Technik allgemein
    Notizen: The electrochemical behavior of a boron-doped diamond film electrode prepared by chemicalvapor deposition was studied. The surface microstructure of the electrode was studied by means ofscanning electron microscopy. The electrochemical behavior of the electrode was investigated bycyclic voltammetry and AC Impedance. The diamond films exhibited a “cauliflower-like”morphology and contained microcrystallites. The results showed the electrode having a very widepotential window and very low background current. The potential windows in acidic, neutral oralkaline medium were respectively 4.4[V], 4.0[V] and 3.0[V]. The background current was as lowas -8×10-6~5×10-7[A]. In the electrolyte including Ferri/Ferrocyanide, the electrode surface keptgood activity, and the electrochemical reaction occurring on the surface was a diffusion-controlledreaction, with good quasi- reversibility. Compared with Pt and graphite electrodes, diamondelectrodes can oxidize compounds like phenol effectively, and the process of oxidization was verysimple and complete
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 34 (1996), S. 2149-2156 
    ISSN: 0887-624X
    Schlagwort(e): 2-substituted A-methylene-1,3-dioxolane ; copolymerization ; polymerization mechanism ; Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: Copolymerizations of 4-methylene-2-styryl-1,3-dioxolane (1) and 4-methylene-2-methyl-2-styryl-1,3-dioxolane (2) with electron-deficient monomers, such as maleic anhydride (MA) and acrylonitrile (AN) were investigated. Only homopolymer of 1 was obtained from the copolymerization of 1 with MA in the presence or absence of AIBN. The copolymerization of 1 and AN with AIBN as initiator gave a copolymer consisting of three kinds of repeating units. Reaction of 2 with MA gave a crystalline product with and without AIBN present. A nine-membered ring structure is proposed for this product based on its IR, UV, proton and 13C-NMR spectra, as well as elemental analysis. No polymer was obtained from the copolymerization of 2 and AN with or without AIBN initiator. Based on the structures of the products obtained from the copolymerization, a number of polymerization mechanisms are proposed. © 1996 John Wiley & Sons, Inc.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    ISSN: 1432-1955
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Die vonMacracanthorhynchus hirudinaceus verursachten Läsionen im Dünndarm von experimentell infizierten Hausschweinen (7 Tage p.i. und 84 Tage p.i.) wurden licht- und elektronenmikroskopisch untersucht. Die Würmer der 84 Tage alten Infektion waren tiefer in die Darmwand eingedrungen als die 7 Tage alten Würmer. Ihr Präsoma wurde von Entzündungsbzw. Bindegewebe umhüllt, das zahlreiche Plasmazellen enthielt. Bei 7 Tage alten Infektionen wurde noch keine Fibrose nachgewiesen. Eosinophilen-ähnliche Granulozyten, die an den Proboscishaken akkumulierten, herrschten in der Läsion vor. Eine osmiophile Gleitflüssigkeit, die offenbar an der Basis der Proboscishaken ausgeschieden wurde, schien eine stark antigene Wirkung auf die Leukozyten des Schweins auszuüben. In keinem Fall wurden Würmer angetroffen, die die gesamte Darmwand perforiert hatten, wie es in China bei Menschen beschrieben wurde.
    Notizen: Abstract One and 12 weeks after infection the lesions in the small intestine of two domestic pigs caused byMacracanthorhynchus hirudinaceus were studied by means of light and electron microscopy. Worms of 7 d.p.i. were found to have penetrated with their presoma into the tunica propria and partly into the tunica muscularis where they had caused local mechanic destructions and heavy eosinophilic-like and hemorrhagic reactions. Most eosinophilic-like granulocytes were attracted to the proboscis hooks, at the base of which an osmiophilic substance apparently was excreted. Worms of 84 d.p.i. had penetrated with their proboscis deeply into the tunica muscularis. The presoma had become encapsulated by a solid capsule of necrotic/inflammatory tissue in its inner part and by filamentous connective tissue in its outer part. The predominant leucocytes in the inflammatory tissue now were plasma cells indicating a progressive immune reaction. No worms were found to have perforated the entire intestinal wall as was described from human patients in China.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Chirality 4 (1992), S. 137-141 
    ISSN: 0899-0042
    Schlagwort(e): 2-arylpropionic acids ; nonsteroidal antiinflammatory drugs ; stereoselective ; coenzyme A thioesters ; chiral inversion ; oxidative phosphorylation ; Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The effects of the enantiomers of ibuprofen (0.25 and 0.50 mmol/kg b.w.) and flurbiprofen (0.01, 0.03, and 0.06 mmol/kg b.w.) on the β-oxidation of palmitate were investigated in the rat. The mean cumulative exhalation of 14CO2 after ip administration of [U-14C]palmitic acid was significantly reduced over 6 h by ibuprofen at the higher dose but not at the lower dose for either enantiomer. There was no difference between the enantiomers, the reduction over 6 h being 31.3 and 33.0% for (R)- and (S)-ibuprofen, respectively. There was also a significant inhibition of β-oxidation by flurbiprofen at all 3 doses. Again, there was no stereoselectivity evident in this inhibition. Flurbiprofen was much more potent than ibuprofen in eliciting this effect, the 0.01mmol/kg dose giving a similar reduction in β-oxidation as observed for the 0.50 mmol/kg dose of ibuprofen. The data support the hypothesis that inhibition of the in vivo β-oxidation of palmitate by ibuprofen and flurbiprofen is primarily via a nonstereoselective noncoenzyme A-dependent mechanism. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Publikationsdatum: 2022-05-26
    Beschreibung: © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Lamb, D. C., Hargrove, T. Y., Zhao, B., Wawrzak, Z., Goldstone, J. V., Nes, W. D., Kelly, S. L., Waterman, M. R., Stegeman, J. J., & Lepesheva, G. I. Concerning P450 evolution: structural analyses support bacterial origin of sterol 14α-demethylases. Molecular Biology and Evolution, (2020): msaa260, doi:10.1093/molbev/msaa260.
    Beschreibung: Sterol biosynthesis, primarily associated with eukaryotic kingdoms of life, occurs as an abbreviated pathway in the bacterium Methylococcus capsulatus. Sterol 14α-demethylation is an essential step in this pathway and is catalyzed by cytochrome P450 51 (CYP51). In M. capsulatus, the enzyme consists of the P450 domain naturally fused to a ferredoxin domain at the C-terminus (CYP51fx). The structure of M. capsulatus CYP51fx was solved to 2.7 Å resolution and is the first structure of a bacterial sterol biosynthetic enzyme. The structure contained one P450 molecule per asymmetric unit with no electron density seen for ferredoxin. We connect this with the requirement of P450 substrate binding in order to activate productive ferredoxin binding. Further, the structure of the P450 domain with bound detergent (which replaced the substrate upon crystallization) was solved to 2.4 Å resolution. Comparison of these two structures to the CYP51s from human, fungi, and protozoa reveals strict conservation of the overall protein architecture. However, the structure of an “orphan” P450 from nonsterol-producing Mycobacterium tuberculosis that also has CYP51 activity reveals marked differences, suggesting that loss of function in vivo might have led to alterations in the structural constraints. Our results are consistent with the idea that eukaryotic and bacterial CYP51s evolved from a common cenancestor and that early eukaryotes may have recruited CYP51 from a bacterial source. The idea is supported by bioinformatic analysis, revealing the presence of CYP51 genes in 〉1,000 bacteria from nine different phyla, 〉50 of them being natural CYP51fx fusion proteins.
    Beschreibung: The study was supported by National Institutes of Health (Grant No. R01 GM067871 to G.I.L.) and by a UK-USA Fulbright Scholarship and the Royal Society (to D.C.L.).
    Schlagwort(e): sterol biosynthesis ; evolution ; cytochrome P450 ; CYP51 redox partner ; crystallography
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Publikationsdatum: 2023-02-25
    Beschreibung: © The Author(s), 2022. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Lamb, D. C., Goldstone, J. V., Zhao, B., Lei, L., Mullins, J. G. L., Allen, M. J., Kelly, S. L., & Stegeman, J. J. Characterization of a virally encoded flavodoxin that can drive bacterial cytochrome P450 monooxygenase activity. Biomolecules, 12(8), (2022): 1107, https://doi.org/10.3390/biom12081107.
    Beschreibung: Flavodoxins are small electron transport proteins that are involved in a myriad of photosynthetic and non-photosynthetic metabolic pathways in Bacteria (including cyanobacteria), Archaea and some algae. The sequenced genome of 0305φ8-36, a large bacteriophage that infects the soil bacterium Bacillus thuringiensis, was predicted to encode a putative flavodoxin redox protein. Here we confirm that 0305φ8-36 phage encodes a FMN-containing flavodoxin polypeptide and we report the expression, purification and enzymatic characterization of the recombinant protein. Purified 0305φ8-36 flavodoxin has near-identical spectral properties to control, purified Escherichia coli flavodoxin. Using in vitro assays we show that 0305φ8-36 flavodoxin can be reconstituted with E. coli flavodoxin reductase and support regio- and stereospecific cytochrome P450 CYP170A1 allyl-oxidation of epi-isozizaene to the sesquiterpene antibiotic product albaflavenone, found in the soil bacterium Streptomyces coelicolor. In vivo, 0305φ8-36 flavodoxin is predicted to mediate the 2-electron reduction of the β subunit of phage-encoded ribonucleotide reductase to catalyse the conversion of ribonucleotides to deoxyribonucleotides during viral replication. Our results demonstrate that this phage flavodoxin has the potential to manipulate and drive bacterial P450 cellular metabolism, which may affect both the host biological fitness and the communal microbiome. Such a scenario may also be applicable in other viral-host symbiotic/parasitic relationships.
    Beschreibung: The study was supported by the National Institutes of Health grant 5U41HG003345 (J.V.G.), by the Woods Hole Center for Oceans and Human Health, NIH P01 ES021923 and NSF OCE-1314642 (J.J.S.), and by a Fulbright Scholarship (to D.C.L.). Funding at Swansea University supported by the European Regional Development Fund/Welsh European Funding Office via the BEACON project (S.L.K).
    Schlagwort(e): Flavodoxin ; Virus/phage ; Cytochrome P450 ; Evolution ; Bacteria
    Repository-Name: Woods Hole Open Access Server
    Materialart: Article
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Publikationsdatum: 2017-06-01
    Print ISSN: 0269-7491
    Digitale ISSN: 1873-6424
    Thema: Energietechnik
    Publiziert von Elsevier
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Publikationsdatum: 2020-06-08
    Beschreibung: Immature T cells undergo a process of positive selection in the thymus when their new T cell receptor (TCR) engages and signals in response to self-peptides. As the T cell matures, a slew of negative regulatory molecules, including the inhibitory surface glycoprotein CD5, are up-regulated in proportion to the strength of the self-peptide signal. Together these regulators dampen TCR-proximal signaling and help avoid any subsequent peripheral activation of T cells by self-peptides. Paradoxically, antigen-specific T cells initially expressing more CD5 (CD5hi) have been found to better persist as effector/memory cells after a peripheral challenge. The molecular mechanisms underlying such a duality in CD5 function is not clear. We found that CD5 alters the basal activity of the NF-κB signaling in resting peripheral T cells. When CD5 was conditionally ablated, T cells were unable to maintain higher expression of the cytoplasmic NF-κB inhibitor IκBα. Consistent with this, resting CD5hiT cells expressed more of the NF-κB p65 protein than CD5locells, without significant increases in transcript levels, in the absence of TCR signals. This posttranslationally stabilized cellular NF-κB depot potentially confers a survival advantage to CD5hiT cells over CD5loones. Taken together, these data suggest a two-step model whereby the strength of self-peptide–induced TCR signal lead to the up-regulation of CD5, which subsequently maintains a proportional reserve of NF-κB in peripheral T cells poised for responding to agonistic antigen-driven T cell activation.
    Print ISSN: 0027-8424
    Digitale ISSN: 1091-6490
    Thema: Biologie , Medizin , Allgemeine Naturwissenschaft
    Standort Signatur Erwartet Verfügbarkeit
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