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91.
The effect of chronic exposure of sublethal concentration (5%) of vegetable oil factory effluent on ovarian maturation of Channa punctatus was studied. The process of ovarian recrudescence was significantly retarded as evidenced by the low ovarian weights and low occurrence of Stage III (Yolky) oocytes in the ovaries of effluent-exposed fish. A high incidence of atresia was also noticed in the ovaries of fish exposed to the effluent. 相似文献
92.
Fernando González-Andrés Pedro A. Casquero Cristina San-Pedro Elías Hernández-Sánchez 《Genetic Resources and Crop Evolution》2007,54(1):27-44
All the accessions (35) of white lupin (Lupinus albus L.) landraces collected from northwest Iberian plateau and maintained at the Spanish germplasm collection (CRF of INIA),
were studied with the general objective of assessing the biodiversity of these landraces and to ascertain their value as genetic
resources for the development of germplasm adapted to the areas where they were collected with long and chilly winters. The
characterization study comprised 51 qualitative and 50 quantitative characters. Quantitative parameters were analyzed by Principal
Components Analysis (PCA). The 2-dimensional plot (49.3% of cumulative variability) formed a main group of accessions and
4 outliers (#1, #9, #27 and #28) separated in the first PC. The characters with a higher contribution to the first PC were
inflorescence length, leaf petiole length and leaf central foliole area. The presence of alkaloids, the percentage of plants
killed by soil borne fungal diseases, the phenology, the yield per plant and yield components were also assessed. Twenty six
accessions (the main group in the PCA plot) showed high homogeneity, with the following highlights: bitterness, indeterminate
growth habit, early ripeness and spring sowing with the exception of #18, in which seeding date is unknown and it had a later
phenology. By contrast accessions #9 and #27 were bitter of autumn sowing with determinate growing habit and they had the
longest values of primary inflorescence length and a later phenology when they were sown in spring. Average values for yield
and yield components showed a broad range of variation between accessions. The main yield component was the number of pods
per plant. Accession #22 had the highest mean seed mass, although this had not significant influence in yield. Accession #17
showed the highest yield and #1 the lowest. This last also had the lowest values of inflorescence length, leaf petiole length
and leaf central foliole area. No significant differences of resistance to soil-borne fungi were found between accessions.
The year had a significant effect in the phenology, yield and yield components except for number of seeds per pod. The studied
material might be of interest for the development of spring sowing germplasm adapted to north Iberian peninsula. 相似文献
93.
Woffenden HM Ames JM Chandra S Anese M Nicoli MC 《Journal of agricultural and food chemistry》2002,50(17):4925-4933
Pale malts were prepared using standard and rapid kilning regimes that differed in the temperature and moisture profiles in the kiln. Samples were taken over the last 9 h of kilning, that is, at 18, 20, 22, 25, and 27 h. Antioxidant activity, assessed by redox potential, scavenging of the 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation (ABTS*+), and ferric reducing/antioxidant power (FRAP), increased at moisture levels below 6.7% for both regimes. The 27 h malt exposed to the rapid regime (moisture content of 4.8%) had a higher activity than the 27 h standard regime sample (moisture content of 4.8%). None of the malts scavenged oxygen. Pro-oxidant activity profiles were different for the malts obtained using each regime and, at 27 h, the rapid procedure gave malt with higher activity. Levels of (+)-catechin and ferulic acid (the most abundant phenolic compounds identified) generally increased as the moisture content of malt fell below 6.7%. Differences in antioxidant and pro-oxidant activities of the 27 h malts are partly attributed to the Maillard reaction, as evidenced by lower L* and higher b* values and higher levels of Maillard-derived flavor compounds, in the sample obtained by the rapid procedure. Levels of lipid-derived flavor compounds were significantly higher after 27 h of kilning using the rapid procedure. 相似文献
94.
Development of multiclass methods for drug residues in eggs: silica SPE cleanup and LC-MS/MS analysis of ionophore and macrolide residues 总被引:1,自引:0,他引:1
A method was developed that is suitable for screening eggs for a variety of nonpolar residues in a single procedure. Residues are extracted by silica solid-phase extraction (SPE). Analysis is conducted via reverse-phase gradient liquid chromatography, electrospray ionization, and tandem ion trap mass spectrometry. For screening purposes (based on a single precursor-product ion transition) the method can detect ionophore (lasalocid, monensin, salinomycin, narasin) and macrolide (erythromycin, tylosin) residues in egg at approximately 1 ng/mL (ppb) and above and novobiocin residues at approximately 3 ppb and above. Conditions are described for confirmatory analysis based on multiple ions in the product ion spectrum. The extraction efficiency for ionophores was estimated at 60-85%, depending on drug. Recovery of macrolides and novobiocin was not as good (estimated at 40-55% after a hexane wash of the final extract was included), but the method consistently screened and confirmed these residues at concentrations below the target of 10 ppb. The method was applied to eggs from hens dosed with each drug individually. Lasalocid was found to have the highest probability of detection in eggs based on its high ionization efficiency and higher rate of deposition relative to the other drugs. The method is part of a larger scheme to provide surveillance methods for a wide variety of drug residues in eggs. 相似文献
95.
96.
Natella F Belelli F Gentili V Ursini F Scaccini C 《Journal of agricultural and food chemistry》2002,50(26):7720-7725
Postprandial hyperlipemia is a well-defined risk factor for atherosclerosis. A reasonable contributing mechanism could involve the postprandial increase of plasma lipid hydroperoxides (LPO) affecting the oxidant/antioxidant balance and increasing the susceptibility of LDL to oxidation. Wine has been shown to prevent both these events. The present study was designed to investigate the effect of supplementing a meal with grape seed proanthocyanidins (the main phenolic antioxidant of red wine) on plasma postprandial oxidative stress. In two different sessions, 8 healthy volunteers consumed the same test meal rich in oxidized and oxidizable lipids without (control) or with 300 mg of a proanthocyanidin-rich grape seeds extract (GSE). Lipid hydroperoxide concentration, antioxidant status, and LDL resistance to oxidative modification were measured in postprandial plasma. The content of LPO in chylomicrons was 1.5-fold higher after the control meal than after the GSE-supplemented meal. Plasma LPO increased only after consumption of the control meal. The plasma antioxidant capacity increased in the postprandial phase only following the GSE supplemented meal. LDL isolated 3 h after the control meal tended to be more susceptible to oxidative modification (but the difference did not reach statistical significance). An opposite trend was observed following the GSE supplemented meal. In conclusion, the supplementation of a meal with GSE minimizes the postprandial oxidative stress by decreasing the oxidants and increasing the antioxidant levels in plasma, and, as a consequence, enhancing the resistance to oxidative modification of LDL. 相似文献
97.
Helianthinin, the main storage protein of sunflowers, has low water solubility and does not form a gel when heated; this behavior is different from other 11S globulins and limits its food applications. To understand this particular behavior, changes on helianthinin association-dissociation state induced by modifications in pH and ionic strength were analyzed. The influence of these different medium conditions on its thermal stability and tendency to form aggregates was also studied. Helianthinin behavior at different pH values and ionic strengths is similar to other 11S globulins except that it remains in a trimeric form at pH 11. Helianthinin thermal stability is higher than other 11S globulins but is lower than oat 11S globulin. Alkaline pH produces a 10 degrees C decrease of its denaturation temperature and also of the cooperativity of denaturation process, but it does not affect the denaturation activation energy. The decrease in thermal stability with the pH increase is also manifested by its tendency to form aggregates by SH/SS interchange reactions. When thermal treatments at alkaline pH are performed, all helianthinin subunits form aggregates, characterized by a higher proportion of beta-polypeptides than alpha-polypeptides, which is an indication that aggregation is accompanied by dissociation. Treatments at 80 degrees C are sufficient to induce aggregation but not to produce denaturation, and in these conditions hexameric forms remain after the treatment. 相似文献
98.
Cristina Martínez-Garza Marcela Osorio-BeristainDavid Valenzuela-Galván Alondra Nicolás-Medina 《Forest Ecology and Management》2011,262(12):2207-2218
Domestic livestock grazing and firewood extraction are chronic and pervasive disturbances in dry secondary forest that reduce diversity and modify composition. Exclosure of such disturbances may allow the reestablishment of original diversity. To investigate potential vegetation recovery following 30 years of perturbation, seed rain was evaluated monthly during 3 years in 96 0.78 m2 seed traps located in eight exclosures established in 2006 in a species-poor secondary dry forest in central Mexico. Twelve additional seed traps were located outside the exclosures in 2010 for comparison purposes. Baseline diversity of seed sources (trees, ?5 cm DBH) was recorded to compare standing tree composition with seed rain. Also, baseline diversity of potential primary (birds) and secondary (ants) dispersal vectors were registered to infer current plant-animal interactions. Total seed rain over 3 years within the exclosures comprised 180,375 seeds from 61 woody species, an average of 1.12 seeds/m2/month. Half of these species (31) and 95% of the seeds falling within the exclosures belonged to trees typical of perturbed sites. Sixty percent of all recorded seeds belonged to an early-successional, bird-dispersed shrub (Hamelia patens Jacq., Rubiaceae). Seed rain at one non-excluded plot was dominated by the wind-dispersed early-successional tree Heliocarpus sp. (Tiliaceae). Richness and seed density increased significantly in the second year of exclusion; however, by the third year, richness remained constant while seed density decreased. Seed rain was richer and more abundant during the dry season and was dominated by wind-dispersed species. Phenology, successional status and the dispersal modes of woody species explained most variance in richness and seed density of seed rain in early-successional dry forest. Seeds of early-successional species were dispersed in equal measure by abiotic and biotic vectors, whereas biotic vectors dispersed a higher density of late-successional seeds. The amount and timing of fall of abiotically dispersed seeds of the three most abundant species in the standing tree community may prolong their current domination of the landscape. However, even when richness in the seed rain within exclosures remained constant through time, composition was gradually shifting towards animal-dispersed species which may start a positive feedback producing an increase in animal visitation and a further increase of richness. 相似文献
99.
Maria Margarida Ribeiro Leopoldo Sanchez Carla Ribeiro Fátima Cunha José Araújo Nuno M. G. Borralho Cristina Marques 《Annals of Forest Science》2011,68(4):701-714
• Introduction
Tree genetic improvement programs usually lack, in general, pedigree information. Since molecular markers can be used to estimate the level of genetic similarity between individuals, we genotyped a sample of a Portuguese Eucalyptus globulus breeding population—a reference population of 125 individuals—with 16 microsatellites (SSR). 相似文献100.
Effect of coupling media on velocity and attenuation of ultrasonic waves in Brazilian wood 总被引:1,自引:0,他引:1
Raquel?Gon?alvesEmail author Alex?Julio?Trinca Gisleiva?Cristina?dos?Santos Ferreira 《Journal of Wood Science》2011,57(4):282-287
Coupling media are necessary to ensure that transducers bond to wood specimens to minimize coupling losses and improve the
accuracy of ultrasonic measurements. There are several types of coupling media available, and the optimal choice is not known.
In this work, we analyzed the results of ultrasonic wave attenuation for 0.1-MHz longitudinal and transverse transducers with
six different materials as coupling media in nine species of Brazilian wood with densities in the range 700–1170 kg/m3. Tests were performed using constant pressure on the transducer and with wave propagation in the longitudinal direction.
For transverse transducers, the polarization was in the radial and tangential directions. The results were analyzed statistically
and showed that, for attenuation in both longitudinal and transverse waves, the material used for coupling had significant
effects, whereas the wood species had no effect. For longitudinal waves, the statistical evaluation showed that the coupling
material performance was strongly dependent on the species of wood, but it was not possible to observe any tendency of behavior
associated with specific anatomical properties. 相似文献