Caffeine Metabolism
Mostrando 1-12 de 15 artigos, teses e dissertações.
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1. EFEITO in vitro DE Paullinia cupana NO METABOLISMO OXIDATIVO DE ESPERMATOZÓIDES HUMANOS EXPOSTOS AO CLORETO DE METILMERCÚRIO / EFFECT OF Paullinia cupana in vitro oxidative metabolism HUMAN SPERM EXPOSED TO CHLORIDE METHYLMERCURY
Investigations suggests that methylmercury (MeHg) toxicitiy is related to oxidative stress promotion caused by lipid peroxidation of cell membranes as well as genotoxicity. The methylmercury (MeHg) exposition causes production of adverse effects as deterioration of semen quality, testicular degeneration, and male reproductive failure. Since human sperm is a
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 14/02/2012
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2. Caffeine degradation in leaves and fruits of coffea arabica and coffea dewevrei.
The coffee species Coffea dewevrei and Coffea arabica have marked differences in caffeine metabolism and the control of the caffeine content during fruit ripening and leaf aging is still not clear. The aim of this work was a detailed investigation on the alkaloid degradation in young and aged leaves, and immature and mature fruits of these species. Young and
Pesquisa Agropecuaria Brasileira. Publicado em: 2011
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3. Papel da alantoina na nutrição nitrogenada e resposta antioxidativas de celulas de cafe em suspensão
Cellular suspension of coffee was used as model to study the role of allantoin in nitrogen nutrition of coffee and the effect of abiotics stress on antioxidant enzymes in coffee. Some studies have reported on the importance of the ureides as nitrogen source in algae and yeast. However, knowing that allantoin is a nitrogen source of N2-fixing plants, informat
Publicado em: 2004
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4. Metabolism of N-methylpurines by a Pseudomonas putida strain isolated by enrichment on caffeine as the sole source of carbon and nitrogen.
Pseudomonas putida, strain 40, originally isolated by enrichment on caffeine as the sole source of carbon and nitrogen, has been developed to grow on 0.5% caffeine. The organism will grow on any N-methyl derivative of xanthine containing one or more methyl groups at the 1, 3, or 7 positions. An investigation of the activities of resting cell suspensions and
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5. Potassium-dependent increases in cytosolic pH stimulate metabolism and motility of mammalian sperm.
Sperm cytosolic pH, determined by the spectral properties of intracellular carboxyfluorescein, is decreased rapidly by the diffusion and subsequent dissociation of the uncharged weak acids pyruvic, lactic, or hydroxybutyric and is increased by diffusion and subsequent intracellular protonation of the weak base NH3. Metabolic and kinetic activity increases dr
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6. Regulation of Purine Metabolism in Intact Leaves of Coffea arabica.
The capacity of Coffea arabica leaves (5- x 5-mm pieces) to synthesize de novo and catabolize purine nucleotides to provide precursors for caffeine (1,3,7-trimethylxanthine) was investigated. Consistent with de novo synthesis, glycine, bicarbonate, and formate were incorporated into the purine ring of inosine 5[prime]-monophosphate (IMP) and adenine nucleoti
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7. Metabolism of Adenosine 3′,5′-Cyclic Monophosphate and Induction of Fruiting Bodies in Coprinus macrorhizus
The adenyl cyclase and phosphodiesterase metabolizing adenosine 3′,5′-cyclic monophosphate (cyclic AMP) were detected in mycelia of strains of Coprinus macrorhizus which form fruiting bodies, but not in those of strains which do not form fruiting bodies. The adenyl cyclase synthesized cyclic AMP from adenosine triphosphate. The phosphodiesterase degr[UNK
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8. Respiration of 13C-Labeled Substrates Added to Soil in the Field and Subsequent 16S rRNA Gene Analysis of 13C-Labeled Soil DNA
Our goal was to develop a field soil biodegradation assay using 13C-labeled compounds and identify the active microorganisms by analyzing 16S rRNA genes in soil-derived 13C-labeled DNA. Our biodegradation approach sought to minimize microbiological artifacts caused by physical and/or nutritional disturbance of soil associated with sampling and laboratory inc
American Society for Microbiology.
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9. Chemically induced premature mitosis: differential response in rodent and human cells and the relationship to cyclin B synthesis and p34cdc2/cyclin B complex formation.
Normal eukaryotic cells do not initiate mitosis until DNA replication has been completed. This requirement can be bypassed by exposing cells to certain chemicals. We report here that chemically induced premature mitosis is not readily achieved in all mammalian species. Although hamster cells underwent premature mitosis following treatment with caffeine, the
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10. Excitation-contraction coupling in single guinea-pig ventricular myocytes exposed to hydrogen peroxide.
1. The effects of hydrogen peroxide (H2O2), an in vitro free radical generating system, on excitation-contraction (E-C) coupling were studied in isolated adult guinea-pig ventricular myocytes using Ca(2+)-sensitive dyes and the patch-clamp technique. 2. In paced myocytes loaded with indo-1 AM, 1 mM H2O2 briefly increased, then decreased the amplitude of intr
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11. Enhanced Toxicity for Mice of 6-Mercaptopurine with Bacterial Endotoxin
The toxicity of 6-mercaptopurine was potentiated by 2 mg of either Escherichia coli 026:B6 B endotoxin or Salmonella typhosa 0901 W endotoxin per kg. Nonlethal doses of heat-killed, gram-negative bacteria were also capable of potentiating the lethality of 6-mercaptopurine (6-MP). Salmonella minnesota S, the wild-type strain, and S. minnesota Re 595, a mutant
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12. Characteristics of a 5-hydroxytryptamine-sensitive adenylate cyclase in intact and intracellularly perfused squid axons.
1. Cyclic AMP metabolism was studied in intact and intracellularly perfused axons. 2. Cyclic AMP content of intact axons lay within the range 10-100 nmol kg-1 axoplasm. This was increased by exposure to caffeine (2-fold) and to 5-HT (15-fold). The caffeine-sensitive cyclic AMP increase was 30-fold larger in the presence of 5-HT. 3. A reduction in sodium conc