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41.
Antioxidant activity of olive pulp and olive oil phenolic compounds of the arbequina cultivar 总被引:3,自引:0,他引:3
Morelló JR Vuorela S Romero MP Motilva MJ Heinonen M 《Journal of agricultural and food chemistry》2005,53(6):2002-2008
The aim of this study was to characterize antioxidant activities of phenolic compounds that appear in olive pulp and olive oils using both radical scavenging and antioxidant activity tests. Antiradical and antioxidant activities of olive pulp and olive oil phenolic compounds were due mainly to the presence of a 3,4-dihydroxy moiety linked to an aromatic ring, and the effect depended on the polarity of the phenolic compound. Glucosides and more complex phenolics exhibited higher antioxidant activities toward oxidation of liposomes, whereas in bulk lipids aglycons were more potent antioxidants with the exception of oleuropein. Lignans acted as antioxidants only in liposomes, which could partly be due to their chelating activity, because liposome oxidation was initiated by cupric acetate. The antioxidant activity of virgin olive oil is principally due to the dialdehydic form of elenolic acid linked to hydroxytyrosol (3,4-DHPEA-EDA), a secoiridoid derivative (peak RT 36, structure unidentified), and luteolin. 相似文献
42.
Fernando Shintate Galindo Marcelo Carvalho Minhoto Teixeira Filho Salatiér Buzetti José Mateus Kondo Santini Eduardo Henrique Marcandalli Boleta Willian Lima Rodrigues 《Journal of plant nutrition》2020,43(8):1057-1069
AbstractNew studies are needed to optimize the nitrogen (N) amount that can be applied to utilize the Azospirillum brasilense benefits. In addition, information regarding the interaction between the urease inhibitor and biological nitrogen fixation (BNF) and how they affect the macronutrients accumulation are also needed. We evaluate the effect of N sources and doses associated with A. brasilense regarding the macronutrients accumulation in straw and grains and wheat grain yield in tropical conditions. A randomized block experimental design was used with four replications in a 2?×?5?×?2 factorial arrangement as follows: two N sources (urea and urea with urease enzyme inhibitor NBPT; five N doses (0, 50, 100, 150, and 200?kg ha?1) applied in topdressing; with and without A. brasilense inoculation. We found that an increase in N doses positively influenced the accumulation of macronutrients in straw and grains and the wheat grain yield. N sources have similar effects. Inoculation with A. brasilense increased accumulation of Mg and S in straw and P, Ca, and Mg in grains, regardless of the N dose. The inoculation with A. brasilense associated with 140?kg ha?1 of N increased wheat grain yield. The inoculation can contribute in a more sustainable way to wheat nutrition and optimizing N fertilization. 相似文献
43.
Renan Francisco Rimoldi Tavanti Grace David Queiroz Anne Caroline Da Rocha Silva Walmor Moya Peres Amanda Pereira Paixão Fernando Shintate Galindo 《Archives of Agronomy and Soil Science》2020,66(6):743-762
ABSTRACTThis study aimed to assess the physiological and biochemical responses of cotton plants to manganese (Mn2+) nutrition. Four cotton genotypes (G1 – TMG 47; G2 – FM 975 WS; G3 – TMG 11 WS and G4 – IMA 8405 GLT) were grown in nutrient solution under two Mn2+ concentrations (2 and 200 µmol L?1) for 10 days. No visible symptoms of Mn2+ toxicity were observed in the genotypes tested. All genotypes showed a marked increase in leaf chlorophylls, pheophytins, carotenoids, sucrose and total sugars concentration in response to high Mn2+ in a nutrient solution. However, the net photosynthetic rate, stomatal conductance, internal carbon dioxide concentration and transpiration decreased in genotypes G1 and G2 growing under 200 µmol L?1. Antioxidant enzymes such as superoxide dismutase (SOD), ascorbate peroxidase (APX) and glutathione reductase (GR) activities increased in genotypes G1, G3 and G4. Cotton genotypes showed an increased leaf antioxidant and sugar metabolism as a possible strategy to mitigate oxidative stress. The decrease in the net photosynthetic rate and stomatal conductance; the increased antioxidant enzymes activities (SOD, APX and GR); and the increase in leaf sucrose and total sugar concentration were the main physiological and biochemical responses in cotton plants to Mn2+ stress. 相似文献
44.
Fernández M Picó Y Girotti S Mañes J 《Journal of agricultural and food chemistry》2001,49(8):3540-3547
Pesticides applied in extended agricultural fields may be controlled by means of bioindicators, such as honeybees, in which are the pesticides bioaccumulate. Liquid chromatography-atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS) experiments with positive (PI) and negative (NI) ion modes were optimized for the analysis of 22 organophosphorus pesticides in honeybee samples. The extraction required 3 g of sample, which was extracted with acetone. The extract was purified with coagulating solution and reextracted with Cl(2)CH(2). Pesticides studied could be detected by both ionization modes except for parathion, parathion-methyl, and bromophos, which did not give signals in PI mode, and triazophos, which was not detected in NI mode. Fragmentation voltage and vaporizer temperature were optimized to achieve the highest sensitivity. The spectra profile of each pesticide in PI mode showed the [M + H](+) ion as the main signal, whereas in NI mode only fragment ions were shown. The detection limit obtained in selected ion monitoring mode ranged from 1 to 15 microg kg(-1). The average recoveries from spiked honeybees at various concentration levels (0.5-5 mg kg(-1)) exceeded 65% with relative standard deviations of 4-15%. The method was applied to real samples, in which residues of coumaphos and dimethoate were detected. 相似文献
45.
The Penman–Monteith equation for reference evapotranspiration (ETo) estimation cannot be applied in many situations, because climatic records are totally or partially not available or reliable.
In these cases, empirical equations that rely on few climatic variables are necessary. Nevertheless, the uncertainty associated
with empirical model estimations is often high. Thus, the improvement of methods relying on few climatic inputs as well as
the development of emergency estimation tools that demand no local climatic records turns into a task of great relevance.
The present study describes different approaches based on multiple linear regression, simple regression and artificial neural
networks (ANNs) to deal with ETo estimation exclusively from exogenous records from secondary stations. This cross-station approach is based on a continental
characterization of the study region, which enables the selection and hierarchization of the most suitable ancillary data
supplier stations. This procedure is compared with different traditional and cross-station approaches, including methodologies
that also consider local temperature inputs. The proposed methods are also evaluated as gap infilling procedures and compared
with a simple methodology, the window averaging. The artificial neural network and the multiple linear regression approaches
present very similar performance accuracies, considerably higher than simple regression and traditional temperature-based
approaches. The proposed input combinations allow similar performance accuracies as ANN models relying on exogenous ETo records and local temperature measurements. The cross-station multiple linear regression procedure is recommended due to
its higher simplicity. 相似文献
46.
W. Conejero C. D. Mellisho M. F. Ortu?o A. Galindo F. P��rez-Sarmiento A. Torrecillas 《Irrigation Science》2011,29(4):299-309
Measurements of midday stem water potential (Ψstem) and maximum daily trunk shrinkage (MDS) were taken over a 4-year period in early maturing peach trees (Prunus persica (L.) Batsch cv. Flordastar) grafted on GF-677 rootstock. Plants were irrigated daily above their water requirements in order
to obtain non-limiting soil water conditions. The results indicated that seasonal reference equations can be obtained for
MDS and Ψstem using crop reference evapotranspiration (ETo), daily mean vapour pressure deficit (VPDm) and mean daily air temperature (Tm) in the case of MDS, and ETo and VPDm in the case of Ψstem. In this way, VPDm was seen to be the best predictor of MDS and Ψstem, without both were influenced significantly by yield or crop load variations between years. When the postharvest regression
between MDS or Ψstem and the meteorological parameters mentioned were broken down into early and late postharvest periods, the correlation coefficients
improved and were closely related to the presence or absence of sugar-demanding sinks, such as active root growth. A negative
linear relationship between MDS and Ψstem was found, pointing to unchanging radial hydraulic conductivity in the bark tissues and suggesting that MDS depends to a
great extent of the water potential. 相似文献
47.
Characterization of mammalian selenoproteomes 总被引:3,自引:0,他引:3
Kryukov GV Castellano S Novoselov SV Lobanov AV Zehtab O Guigó R Gladyshev VN 《Science (New York, N.Y.)》2003,300(5624):1439-1443
In the genetic code, UGA serves as a stop signal and a selenocysteine codon, but no computational methods for identifying its coding function are available. Consequently, most selenoprotein genes are misannotated. We identified selenoprotein genes in sequenced mammalian genomes by methods that rely on identification of selenocysteine insertion RNA structures, the coding potential of UGA codons, and the presence of cysteine-containing homologs. The human selenoproteome consists of 25 selenoproteins. 相似文献
48.
Pascual JI Méndez J Gómez-Herrero J Baró AM Garcia N Landman U Luedtke WD Bogachek EN Cheng HP 《Science (New York, N.Y.)》1995,267(5205):1793-1795
Material structures of reduced dimensions exhibit electrical and mechanical properties different from those in the bulk. Measurements of room-temperature electronic transport in pulled metallic nanowires are presented, demonstrating that the conductance characteristics depend on the length, lateral dimensions, state and degree of disorder, and elongation mechanism of the wire. Conductance during the elongation of short wires (length l approximately 50 angstroms) exhibits periodic quantization steps with characteristic dips, correlating with the order-disorder states of layers of atoms in the wire predicted by molecular dynamics simulations. The resistance R of wires as long as l approximately 400 angstroms exhibits localization characteristics with In R(l) approximately l(2). 相似文献
49.
Markó IE Stérin S Buisine O Mignani G Branlard P Tinant B Declercq JP 《Science (New York, N.Y.)》2002,298(5591):204-206
The hydrosilylation reaction enables the production of silicon polymers. Platinum-carbene complexes are reported that catalyze the hydrosilylation reaction of alkenes with remarkable efficiency and exquisite selectivity and avoid the formation of platinum colloids. By-products, typically encountered with previous catalytic systems, are suppressed with these platinum derivatives. 相似文献
50.
A Galindo 《Science (New York, N.Y.)》1972,178(62):753-755
Curare and pancuronium have multiple effects on previously undepressed rat diaphragm; these include depression of transmitter output and prolongation of the refractory period of prejunctional structures. The effect of curare on motor nerve terminals is greater than that of pancuronium. Both drugs depress postjunctional receptors; but curare, in addition, raises the threshold for the generation of muscle action potentials. In addition, these results raise questions about the validity of statistical methods used to calculate transmitter output. 相似文献