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排序方式: 共有559条查询结果,搜索用时 15 毫秒
441.
Giuseppe Piccione Stefania CasellaClaudia Giannetto PhD Anna AssenzaGiovanni Caola BCH 《Journal of Equine Veterinary Science》2010
Platelet aggregation is the most important event in the hemostatic process, but no information is available on the stability of samples for aggregation testing in horses. The aim of the present study was to evaluate the effect of different storage conditions on platelet aggregation in horses. The study was carried out on 58 healthy horses of varying breed and gender, ranging in age from 4 to 12 years. Citrated blood samples were collected from all the subjects by means of jugular venipuncture and were used for platelet aggregation measurements. Platelet-rich and platelet-poor plasma samples were prepared by centrifugation and divided into six different aliquots to assess the maximum degree of platelet aggregation and the initial velocity of platelet aggregation at the final concentrations of 1 and 0.5 μM of the aggregating agent. The first aliquot was analyzed within 1 hour after collection at room temperature (22°C), the second 6 hours after collection at 22°C, the third and fourth were refrigerated at 8°C for 6 and 24 hours, respectively, and the fifth and sixth were frozen at −20°C for 24 and 48 hours, respectively. With the help of an aggregometer, platelet responses were quantified, and one-way repeated measures analysis of variance was used to determine significant differences. Probability values of <.05 were considered to be statistically significant. Analysis of variance showed statistically significant differences on maximum degree of platelet aggregation and the initial velocity of platelet aggregation using adenosine diphosphate at final concentrations of 1 and 0.5 μM. The results of this study suggest that the storage of equine plasma for more than 6 hours at room temperature and at 8°C has a significant effect on platelet aggregation, and that the storage of plasma for 24 and 48 hours at −20°C alters platelet aggregation. In conclusion, storage conditions had a statistically significant effect on the parameters of platelet aggregation directly correlated to temperature. 相似文献
442.
Biokinematics under Competitive Racing Conditions in Young Standardbred Trotters: A Preliminary Report 总被引:1,自引:0,他引:1
Jose M. Vilar Francisco Miró Angelo Santana Giuseppe Spinella 《Journal of Equine Veterinary Science》2010
With the aim of evaluating equine performance in competitive trotter horses under normal racing conditions data of stride length, stride frequency and mean horses speed were obtained from 50, 2-year-old Italian winner fillies during the racing and the sprint laps of competition. The enhancement of speed in the sprint lap was obtained by increasing both stride length and stride frequency. Stride frequency for the racing and the sprint laps were (mean ± SD) 133.63 ± 3.93 and 138.97 ± 6.62 strides per minute, respectively and Stride length for the racing and the sprint laps were 7.17 ± 0.17 and 7.30 ± 0.11 m, respectively; mean speed was 48.18 ± 1.09 km/hr. The usefulness of the kinematic assessments is discussed as is its potential reference for future indicators of performance. 相似文献
443.
Use of thermography for high throughput phenotyping of tropical maize adaptation in water stress 总被引:2,自引:0,他引:2
Giuseppe Romano Shamaila Zia Wolfram Spreer Ciro Sanchez Jill Cairns Jose Luis Araus Joachim Müller 《Computers and Electronics in Agriculture》2011,79(1):67-74
In this study the suitability of thermal imaging for phenotyping was investigated as part of a breeding experiment carried out by the International Maize and Wheat Improvement Centre (CIMMYT) at Tlaltizapán experimental station in Mexico. Different subtropical maize genotypes with two replications were screened with respect to their tolerance to water stress. Thermal images of the canopy of 92 different maize genotypes were acquired on two different days in the time interval between anthesis and blister stages (grain filling 1), whereby each picture contained five plots of different genotypes and canopy temperatures calculated for each plot. Significantly, lower canopy temperatures were found in well-watered genotypes compared with water-stressed genotypes. Furthermore significant differences (p < 0.001) between genotypes under water stress were detected using thermal images. A close correlation (p < 0.01–0.001) between canopy temperature or modified Crop water stress index with NDVI and SPAD values was obtained. It may be concluded that genotypes better adapted to drought conditions exhibited lower temperatures.Thermography is a potentially promising method to accelerate the screening process and thereby enhance phenotyping for drought adaptation in maize. 相似文献
444.
Djaouida Rekab Giuseppe Pirajno Emanuele Cettul Flavio Roberto De Salvador Giuseppe Firrao 《European journal of plant pathology / European Foundation for Plant Pathology》2010,127(1):7-12
Notwithstanding the availability of several different real time PCR protocols for “Candidatus Phytoplasma mali”, it is still unclear how informative is the estimation of the concentration of phytoplasma cells in the
leaves of apple proliferation infected trees, and how the reliability of the estimations may be affected by an erratic and
uneven distribution of the pathogen in the host. Here we investigated these issues systematically and showed that phytoplasma
concentration varies significantly among seasons, but not between two cultivars that appeared to have different degree of
susceptibility on the basis of the symptoms displayed. In fully symptomatic trees sampled at the end of the season the phytoplasmas
were detectable in most leaves, but in more than half of the leaves at low concentrations. Both the pattern of colonization
of the canopy and the amount of phytoplasmas varied greatly in trees that show symptom remission, although a direct relation
between symptom severity and colonization could not be established. The sampling of the apple canopy for the purpose of evaluation
of concentration of “Candidatus Phytoplasma mali” should take into consideration the complex pattern of colonization and seasonal variation. 相似文献
445.
446.
Andrea Occhipinti Łukasz Berlicki Samuele Giberti Gabriela Dziȩdzioła Paweł Kafarski Giuseppe Forlani 《Pest management science》2010,66(1):51-58
BACKGROUND: Aiming at the rational design of new herbicides, the availability of the three‐dimensional structure of the target enzyme greatly enhances the optimisation of lead compounds and the design of derivatives with increased activity. Among the most widely exploited herbicide targets is glutamine synthetase. Recently, the structure of a cytosolic form of the maize enzyme has been described, making it possible to verify whether steric, electronic and hydrophobic features of a compound are in agreement with inhibitor–protein interaction geometry. RESULTS: Three series of compounds (aminophosphonates, hydroxyphosphonates and aminomethylenebisphosphonates) were evaluated as possible inhibitors of maize glutamine synthetase. Aminomethylenebisphosphonate derivatives substituted in the phenyl ring retained the inhibitory potential, whereas variations in the scaffold, i.e. the replacement of the second phosphonate moiety with a hydroxyl or an amino residue, resulted in a significant loss of activity. A kinetic characterisation showed a non‐competitive mechanism against glutamate and an uncompetitive mechanism against ATP. A docking analysis suggested the mode of bisphosphonate binding to the active site. CONCLUSION: Results made it possible to define the features required to maintain or enhance the biological activity of these compounds, which represent lead structures to be further exploited for the design of new substances endowed with herbicidal activity. Copyright © 2009 Society of Chemical Industry 相似文献
447.
448.
Low‐molecular‐weight organic acids (LMWOA's) play an important role in soil genesis and plant physiology. Oxalic acid is one of the more common and abundant LMWOA's in forest soils, where it accumulates especially as salts of Ca. In two soils under silver fir (Abies alba Mill.) from Tuscany, Italy, we measured the oxalate concentration of the entire profile. Oxalate was present up to two metres depth, but accumulates preferentially in the upper horizons. We determined also the bulk density of the fine earth, and organic carbon and available phosphorus. In one of the two soils, the oxalate concentration along the profile was regressed negatively with depth and bulk density, and positively with organic C and available P. 相似文献
449.
Curcio M Puoci F Cirillo G Iemma F Spizzirri UG Picci N 《Journal of agricultural and food chemistry》2010,58(22):11883-11887
A molecularly imprinted polymer able to recognize melamine in partially aqueous medium was synthesized using methacrylic acid as functional monomer and ethylene glycol dimethacrylate as cross-linking agent. The bound specificity and selectivity of the obtained material were verified by performing binding experiments with melamine and its structural analogue, 2,4,6-trimethoxy-1,3,5-triazine, respectively, using different aqueous binding media. Finally, the ability of MIP to selectively extract melamine from two real samples, a food supplement and a freeze-dried meat sample, was demonstrated. 相似文献
450.
DNA replication machineries have been studied extensively, but the kinetics of action of their components remains largely unknown. We report a study of DNA synthesis during replication in living Escherichia coli cells. Using single-molecule microscopy, we observed repetitive fluorescence bursts of single polymerase IIIs (Pol IIIs), indicating polymerase exchange at the replication fork. Fluctuations in the amount of DNA-bound single-stranded DNA-binding protein (SSB) reflect different speeds for the leading- and lagging-strand DNA polymerases. Coincidence analyses of Pol III and SSB fluctuations show that they correspond to the lagging-strand synthesis and suggest the use of a new Pol III for each Okazaki fragment. Based on exchanges involving two Pol IIIs, we propose that the third polymerase in the replisome is involved in lagging-strand synthesis. 相似文献