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  1 / 1280 MEDLINE  
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PMID:29207242
Autor:Sobolev V; Arias R; Goodman K; Walk T; Orner V; Faustinelli P; Massa A
Endereço:National Peanut Research Laboratory, Agricultural Research Service, United States Department of Agriculture , P.O. Box 509, Dawson, Georgia 39842, United States.
Título:Suppression of Aflatoxin Production in Aspergillus Species by Selected Peanut (Arachis hypogaea) Stilbenoids.
Fonte:J Agric Food Chem; 66(1):118-126, 2018 Jan 10.
ISSN:1520-5118
País de publicação:United States
Idioma:eng
Resumo:Aspergillus flavus is a soil fungus that commonly invades peanut seeds and often produces carcinogenic aflatoxins. Under favorable conditions, the fungus-challenged peanut plant produces and accumulates resveratrol and its prenylated derivatives in response to such an invasion. These prenylated stilbenoids are considered peanut antifungal phytoalexins. However, the mechanism of peanut-fungus interaction has not been sufficiently studied. We used pure peanut stilbenoids arachidin-1, arachidin-3, and chiricanine A to study their effects on the viability of and metabolite production by several important toxigenic Aspergillus species. Significant reduction or virtually complete suppression of aflatoxin production was revealed in feeding experiments in A. flavus, Aspergillus parasiticus, and Aspergillus nomius. Changes in morphology, spore germination, and growth rate were observed in A. flavus exposed to the selected peanut stilbenoids. Elucidation of the mechanism of aflatoxin suppression by peanut stilbenoids could provide strategies for preventing plant invasion by the fungi that produce aflatoxins.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Aflatoxins); 0 (Hemiterpenes); 0 (Stilbenes); 0 (arachidin-1); 0 (arachidin-3); 0 (chiricanine A); 10048-13-2 (Sterigmatocystin)


  2 / 1280 MEDLINE  
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PMID:29195373
Autor:Szabra D; Prokopiuk A; Mikolajczyk J; Ligor T; Buszewski B; Bielecki Z
Endereço:Institute of Optoelectronics, Military University of Technology, 2 Kaliskiego St., 00-908 Warsaw, Poland.
Título:Air sampling unit for breath analyzers.
Fonte:Rev Sci Instrum; 88(11):115006, 2017 Nov.
ISSN:1089-7623
País de publicação:United States
Idioma:eng
Resumo:The paper presents a portable breath sampling unit (BSU) for human breath analyzers. The developed unit can be used to probe air from the upper airway and alveolar for clinical and science studies. The BSU is able to operate as a patient interface device for most types of breath analyzers. Its main task is to separate and to collect the selected phases of the exhaled air. To monitor the so-called I, II, or III phase and to identify the airflow from the upper and lower parts of the human respiratory system, the unit performs measurements of the exhaled CO (ECO ) in the concentration range of 0%-20% (0-150 mm Hg). It can work in both on-line and off-line modes according to American Thoracic Society/European Respiratory Society standards. A Tedlar bag with a volume of 5 dm is mounted as a BSU sample container. This volume allows us to collect ca. 1-25 selected breath phases. At the user panel, each step of the unit operation is visualized by LED indicators. This helps us to regulate the natural breathing cycle of the patient. There is also an operator's panel to ensure monitoring and configuration setup of the unit parameters. The operation of the breath sampling unit was preliminarily verified using the gas chromatography/mass spectrometry (GC/MS) laboratory setup. At this setup, volatile organic compounds were extracted by solid phase microextraction. The tests were performed by the comparison of GC/MS signals from both exhaled nitric oxide and isoprene analyses for three breath phases. The functionality of the unit was proven because there was an observed increase in the signal level in the case of the III phase (approximately 40%). The described work made it possible to construct a prototype of a very efficient breath sampling unit dedicated to breath sample analyzers.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Butadienes); 0 (Hemiterpenes); 0 (Pentanes); 0 (Volatile Organic Compounds); 0A62964IBU (isoprene); 31C4KY9ESH (Nitric Oxide)


  3 / 1280 MEDLINE  
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PMID:28803474
Autor:Tanaka S; Shiomi S; Ishikawa H
Endereço:Department of Chemistry, Graduate School of Science and Technology, Kumamoto University , 2-39-1, Kurokami, Chuo-ku, Kumamoto 860-8555, Japan.
Título:Bioinspired Indole Prenylation Reactions in Water.
Fonte:J Nat Prod; 80(8):2371-2378, 2017 Aug 25.
ISSN:1520-6025
País de publicação:United States
Idioma:eng
Resumo:Isoprene units derived from dimethylallyl diphosphate (DMAPP) are an important motif in many natural products including terpenoids, carotenoids, steroids, and natural rubber. Understanding the chemical characteristics of DMAPP is an important topic in natural products chemistry, organic chemistry, and biochemistry. We have developed a direct bioinspired indole prenylation reaction using DMAPP or its equivalents as the electrophile in homogeneous aqueous acidic media in the absence of enzyme to provide prenylated indole products. After establishing the bioinspired indole prenylation reaction, this was then used to achieve the synthesis of a series of natural products, namely, N-prenylcyclo-l-tryptophyl-l-proline, tryprostatins, rhinocladins, and terezine D.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Biological Products); 0 (Butadienes); 0 (Dipeptides); 0 (Hemiterpenes); 0 (Indoles); 0 (Organophosphorus Compounds); 0 (Pentanes); 0 (Terpenes); 0 (tryptophyl-proline); 059QF0KO0R (Water); 0A62964IBU (isoprene); 358-72-5 (3,3-dimethylallyl pyrophosphate); 9DLQ4CIU6V (Proline)


  4 / 1280 MEDLINE  
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PMID:28669030
Autor:Moulin M; Alguacil J; Gu S; Mehtougui A; Adams EJ; Peyrottes S; Champagne E
Endereço:Centre de Physiopathologie de Toulouse Purpan, CPTP, INSERM U1043/CNRS UMR5282, 31024, Toulouse, France.
Título:Vγ9Vδ2 T cell activation by strongly agonistic nucleotidic phosphoantigens.
Fonte:Cell Mol Life Sci; 74(23):4353-4367, 2017 Dec.
ISSN:1420-9071
País de publicação:Switzerland
Idioma:eng
Resumo:Human Vγ9Vδ2 T cells can sense through their TCR tumor cells producing the weak endogenous phosphorylated antigen isopentenyl pyrophosphate (IPP), or bacterially infected cells producing the strong agonist hydroxyl dimethylallyl pyrophosphate (HDMAPP). The recognition of the phosphoantigen is dependent on its binding to the intracellular B30.2 domain of butyrophilin BTN3A1. Most studies have focused on pyrophosphate phosphoantigens. As triphosphate nucleotide derivatives are naturally co-produced with IPP and HDMAPP, we analyzed their specific properties using synthetic nucleotides derived from HDMAPP. The adenylated, thymidylated and uridylated triphosphate derivatives were found to activate directly Vγ9Vδ2 cell lines as efficiently as HDMAPP in the absence of accessory cells. These antigens were inherently resistant to terminal phosphatases, but apyrase, when added during a direct stimulation of Vγ9Vδ2 cells, abrogated their stimulating activity, indicating that their activity required transformation into strong pyrophosphate agonists by a nucleotide pyrophosphatase activity which is present in serum. Tumor cells can be sensitized with nucleotide phosphoantigens in the presence of apyrase to become stimulatory, showing that this can occur before their hydrolysis into pyrophosphates. Whereas tumors sensitized with HDMAPP rapidly lost their stimulatory activity, sensitization with nucleotide derivatives, in particular with the thymidine derivative, induced long-lasting stimulating ability. Using isothermal titration calorimetry, binding of some nucleotide derivatives to BTN3A1 intracellular domain was found to occur with an affinity similar to that of IPP, but much lower than that of HDMAPP. Thus, nucleotide phosphoantigens are precursors of pyrophosphate antigens which can deliver strong agonists intracellularly resulting in prolonged and strengthened activity.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (4-hydroxy-3-methyl-2-butenyl diphosphate); 0 (Antigens); 0 (Antigens, CD); 0 (BTN3A1 protein, human); 0 (Butyrophilins); 0 (Hemiterpenes); 0 (Lysosomal-Associated Membrane Protein 1); 0 (Organophosphates); 0 (Organophosphorus Compounds); 0 (Receptors, Antigen, T-Cell, gamma-delta); 0 (Tumor Necrosis Factor-alpha); 0 (triphosphoric acid 1-adenosin-5'-yl ester 3-(3-methylbut-3-enyl) ester); 358-71-4 (isopentenyl pyrophosphate); 82115-62-6 (Interferon-gamma); 8L70Q75FXE (Adenosine Triphosphate)


  5 / 1280 MEDLINE  
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PMID:28631130
Autor:Fernández D; Ramis R; Ortega-Castro J; Casasnovas R; Vilanova B; Frau J
Endereço:Department de Química, Institut Universitari d'Investigació en Ciències de la Salut (IUNICS), Universitat de les Illes Balears, 07122, Palma, Spain.
Título:New insights into human farnesyl pyrophosphate synthase inhibition by second-generation bisphosphonate drugs.
Fonte:J Comput Aided Mol Des; 31(7):675-688, 2017 Jul.
ISSN:1573-4951
País de publicação:Netherlands
Idioma:eng
Resumo:Pamidronate, alendronate, APHBP and neridronate are a group of drugs, known as second-generation bisphosphonates (2G-BPs), commonly used in the treatment of bone-resorption disorders, and recently their use has been related to some collateral side effects. The therapeutic activity of 2G-BPs is related to the inhibition of the human Farnesyl Pyrophosphate Synthase (hFPPS). Available inhibitory activity values show that 2G-BPs act time-dependently, showing big differences in their initial inhibitory activities but similar final IC values. However, there is a lack of information explaining this similar final inhibitory potency. Although different residues have been identified in the stabilization of the R side chain of 2G-BPs into the active site, similar free binding energies were obtained that highlighted a similar stability of the ternary complexes, which in turns justified the similar IC values reported. Free binding energy calculations also demonstrated that the union of 2G-BPs to the active site were 38 to 54 kcal mol energetically more favourable than the union of the natural substrate, which is the basis of the inhibition potency of the hFPPS activity.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Bone Density Conservation Agents); 0 (Diphosphonates); 0 (Hemiterpenes); 0 (Organophosphorus Compounds); 358-71-4 (isopentenyl pyrophosphate); 79778-41-9 (6-amino-1-hydroxyhexane-1,1-diphosphonate); EC 2.5.1.10 (Geranyltranstransferase); OYY3447OMC (pamidronate); X1J18R4W8P (Alendronate)


  6 / 1280 MEDLINE  
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PMID:28605624
Autor:Grabowska-Polanowska B; Skowron M; Miarka P; Pietrzycka A; Sliwka I
Endereço:Institute of Nuclear Physics, Polish Academy of Sciences, Krakow, Poland. Electronic address: beata.grabowska@ifj.edu.pl.
Título:The application of chromatographic breath analysis in the search of volatile biomarkers of chronic kidney disease and coexisting type 2 diabetes mellitus.
Fonte:J Chromatogr B Analyt Technol Biomed Life Sci; 1060:103-110, 2017 Aug 15.
ISSN:1873-376X
País de publicação:Netherlands
Idioma:eng
Resumo:Chromatographic studies on breath composition are aimed at finding volatile markers useful for medical diagnostics or in screening investigations. Studies leading to the development of screening breath tests are especially important for the diagnostics of chronic kidney disease (CKD) and type 2 diabetes mellitus (T2DM). The aim of the presented study was to confirm diagnostic usefulness of chosen volatile compounds detected in breath, which are suggested as potential biomarkers of renal dysfunction and diabetes. Breath analysis were carried out in three groups: 10 healthy volunteers, 10 patients with CKD and 10 patients with CKD and T2DM. All exhaled air samples were analyzed using gas chromatograph (Agilent 6890GC) coupled with mass spectrometer (5975MSD). Thermal desorption was applied as the enrichment method. TMA was detected only in CKD patients. Higher breath concentrations of methanethiol (MeSH) were observed in CKD patients with coexisting diabetes than in patients with renal dysfunction only or in the healthy group. There was a tendency of increasing MeSH concentration in breath with increasing total glutathione in plasma (r=0.53, p=0.0026). Also, a trend of increasing dimethylsulfide (DMS) levels detected in breath was noticed with an increase of hydrogen sulfide concentration in plasma (r=0.74; p=0.00001) as well as with aspartate aminotransferase (AST), (r=0.61; p=0.001). The presented results suggest the possibility of applying TMA, MeSH, and DMS detection in breath as diagnostic methods.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Biomarkers); 0 (Butadienes); 0 (Hemiterpenes); 0 (Methylamines); 0 (Pentanes); 0 (Sulfides); 0 (Volatile Organic Compounds); 0A62964IBU (isoprene); 1364PS73AF (Acetone); LHH7G8O305 (trimethylamine); QS3J7O7L3U (dimethyl sulfide)


  7 / 1280 MEDLINE  
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PMID:28577910
Autor:Thibodeaux CJ; Liu HW
Endereço:Department of Chemistry, McGill University, 801Sherbrooke St. West, Montreal, QC, H3A 0B8, Canada. Electronic address: christopher.thibodeaux@mcgill.ca.
Título:The type II isopentenyl Diphosphate:Dimethylallyl diphosphate isomerase (IDI-2): A model for acid/base chemistry in flavoenzyme catalysis.
Fonte:Arch Biochem Biophys; 632:47-58, 2017 Oct 15.
ISSN:1096-0384
País de publicação:United States
Idioma:eng
Resumo:The chemical versatility of the flavin coenzyme is nearly unparalleled in enzyme catalysis. An interesting illustration of this versatility can be found in the reaction catalyzed by the type II isopentenyl diphosphate:dimethylallyl diphosphate isomerase (IDI-2) - an enzyme that interconverts the two essential isoprene units (isopentenyl pyrophosphate and dimethylallyl pyrophosphate) that are needed to initiate the biosynthesis of all isoprenoids. Over the past decade, a variety of biochemical, spectroscopic, structural and mechanistic studies of IDI-2 have provided mounting evidence that the flavin coenzyme of IDI-2 acts in a most unusual manner - as an acid/base catalyst to mediate a 1,3-proton addition/elimination reaction. While not entirely without precedent, IDI-2 is by far the most extensively studied flavoenzyme that employs flavin-mediated acid/base catalysis. Thus, IDI-2 serves as an important mechanistic model for understanding this often overlooked, but potentially widespread reactivity of flavin coenzymes. This review details the most pertinent studies that have contributed to the development of mechanistic proposals for this highly unusual flavoenzyme, and discusses future experiments that may be able to clarify remaining uncertainties in the chemical mechanism of IDI-2.
Tipo de publicação: JOURNAL ARTICLE; REVIEW
Nome de substância:0 (Flavoproteins); 0 (Hemiterpenes); 0 (Organophosphorus Compounds); 0 (Terpenes); 358-71-4 (isopentenyl pyrophosphate); 358-72-5 (3,3-dimethylallyl pyrophosphate); EC 5.3.3.- (Carbon-Carbon Double Bond Isomerases); EC 5.3.3.2 (isopentenyldiphosphate delta-isomerase)


  8 / 1280 MEDLINE  
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PMID:28478108
Autor:Kajiura H; Suzuki N; Tokumoto Y; Yoshizawa T; Takeno S; Fujiyama K; Kaneko Y; Matsumura H; Nakazawa Y
Endereço:Technical Research Institute, Hitachi Zosen Corporation, 2-2-11 Funamachi, Taisyo, Osaka, 551-0022, Japan.
Título:Two Eucommia farnesyl diphosphate synthases exhibit distinct enzymatic properties leading to end product preferences.
Fonte:Biochimie; 139:95-106, 2017 Aug.
ISSN:1638-6183
País de publicação:France
Idioma:eng
Resumo:Farnesyl diphosphate synthase (FPS) is an essential enzyme in the biosynthesis of prenyl precursors for the production of primary and secondary metabolites, including sterols, dolichols, carotenoids and ubiquinones, and for the modification of proteins. Here we identified and characterized two FPSs (EuFPS1 and EuFPS2) from the plant Eucommia ulmoides. The EuFPSs had seven highly conserved prenyltransferase-specific domains that are critical for activity. Complementation and biochemical analyses using bacterially produced recombinant EuFPS isoforms showed that the EuFPSs had FPP synthesis activities both in vivo and in vitro. In addition to the typical reaction mechanisms of FPS, EuFPSs utilized farnesyl diphosphate (FPP) as an allylic substrate and participated in further elongation of the isoprenyl chain, resulting in the synthesis of geranylgeranyl diphosphate. However, despite the high amino acid similarities between the two EuFPS isozymes, their specific activities, substrate preferences, and final reaction products were different. The use of dimethylallyl diphosphate (DMAPP) as an allylic substrate highlighted the differences between the two enzymes: depending on the pH, the metal ion cofactor, and the cofactor concentration, EuFPS2 accumulated geranyl diphosphate as an intermediate product at a constant rate, whereas EuFPS1 synthesized little geranyl diphosphate. The reaction kinetics of the EuFPSs demonstrated that isopentenyl diphosphate and DMAPP were used both as substrates and as inhibitors of EuFPS activity. Taken together, the results indicate that the biosynthesis of FPP is highly regulated by various factors indispensable for EuFPS reactions in plants.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Hemiterpenes); 0 (Organophosphorus Compounds); 0 (Polyisoprenyl Phosphates); 0 (Sesquiterpenes); 358-71-4 (isopentenyl pyrophosphate); 358-72-5 (3,3-dimethylallyl pyrophosphate); 79W6B01D07 (farnesyl pyrophosphate); EC 2.5.1.10 (Geranyltranstransferase)


  9 / 1280 MEDLINE  
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PMID:28342224
Autor:Murday AS; Chaudhry S; Pauza CD
Endereço:Institute of Human Virology and Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, USA.
Título:Interleukin-18 activates Vγ9Vδ2 T cells from HIV-positive individuals: recovering the response to phosphoantigen.
Fonte:Immunology; 151(4):385-394, 2017 Aug.
ISSN:1365-2567
País de publicação:England
Idioma:eng
Resumo:The study aimed to identify an immunoregulatory factor that restores the phosphoantigen response of Vγ9Vδ2 T cells from HIV-positive individuals on antiretroviral therapy. It was designed to characterize the effects of interleukin-18 (IL-18) on proliferation and effector function in Vγ9Vδ2 T cells from HIV-negative individuals and test whether exogenous IL-18 reconstitutes the Vγ9Vδ2 T-cell response to phosphoantigen from HIV-positive donors. Vγ9Vδ2 T cells from HIV-negative individuals responded strongly to phosphoantigen or aminobisphosphonate stimulation of peripheral blood mononuclear cells (PBMC), whereas cells with similar T-cell receptor profiles from HIV-positive individuals only responded to aminobisphosphonate. Interleukin-18 was higher after aminobisphosphonate stimulation due to activation of the inflammasome pathway. Both IL-18 and IL-18 receptor levels were measured and the activity of exogenous IL-18 on HIV-negative and HIV-positive PBMC was evaluated in terms of Vγ9Vδ2 T-cell proliferation, memory subsets, cytokine expression and CD107a expression. Interleukin-18 stimulation increased proliferation, enhanced the accumulation of effector memory cells, and increased expression of cytotoxic markers in HIV-negative controls. When Vγ9Vδ2 T cells from HIV-positive individuals were stimulated with isopentenyl pyrophosphate in the presence of IL-18, there was increased proliferation, accumulation of memory cells, and higher expression of CD56, NKG2D and CD107a (markers of cytotoxic effector phenotype). Interleukin-18 stimulation specifically expanded the Vγ9-JγP subset of Vγ9Vδ2 T cells, as was expected for normal responses to phosphoantigen. Interleukin-18 is a potent stimulator of Vγ9Vδ2 T-cell proliferation and effector function. Therapies directed at reconstituting Vγ9Vδ2 T-cell activity in HIV-positive individuals should include stimulators of IL-18 or direct cytokine supplementation.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Antigens); 0 (Diphosphonates); 0 (Hemiterpenes); 0 (Imidazoles); 0 (Interleukin-18); 0 (Organophosphorus Compounds); 0 (Receptors, Antigen, T-Cell, gamma-delta); 0 (T-cell receptor Vdelta2, human); 0 (T-cell receptor Vgamma9, human); 358-71-4 (isopentenyl pyrophosphate); 6XC1PAD3KF (zoledronic acid)


  10 / 1280 MEDLINE  
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PMID:28334669
Autor:Li JL; Zhang HH; Yang GP
Endereço:Key Laboratory of Marine Chemistry Theory and Technology, Ocean University of China, Ministry of Education/Collaborative Innovation Center of Marine Science and Technology, Qingdao 266100, China.
Título:Distribution and sea-to-air flux of isoprene in the East China Sea and the South Yellow Sea during summer.
Fonte:Chemosphere; 178:291-300, 2017 Jul.
ISSN:1879-1298
País de publicação:England
Idioma:eng
Resumo:Spatial distribution and sea-to-air flux of isoprene in the East China Sea and the South Yellow Sea in July 2013 were investigated. This study is the first to report the concentrations of isoprene in the China marginal seas. Isoprene concentrations in the surface seawater during summer ranged from 32.46 to 173.5 pM, with an average of 83.62 ± 29.22 pM. Distribution of isoprene in the study area was influenced by the diluted water from the Yangtze River, which stimulated higher in-situ phytoplankton production of isoprene rather than direct freshwater input. Variations in isoprene concentrations were found to be diurnal, with high values observed during daytime. A significant correlation was observed between isoprene and chlorophyll a in the study area. Relatively higher isoprene concentrations were recorded at stations where the phytoplankton biomass was dominated by Chaetoceros, Skeletonema, Pennate-nitzschia, and Thalassiosira. Positive correlation was observed between isoprene and methyl iodide. In addition, sea-to-air fluxes of isoprene approximately ranged from 22.17 nmol m d -537.2 nmol m d , with an average of 161.5 ± 133.3 nmol m d . These results indicate that the coastal and shelf areas may be important sources of atmospheric isoprene.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Air Pollutants); 0 (Butadienes); 0 (Hemiterpenes); 0 (Pentanes); 0 (Water Pollutants, Chemical); 0A62964IBU (isoprene); 1406-65-1 (Chlorophyll); YF5Q9EJC8Y (chlorophyll a)



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