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31.
Aleman M Magdesian KG Peterson TS Galey FD 《Journal of the American Veterinary Medical Association》2007,230(12):1822-1826
CASE DESCRIPTION: A 4-month-old American Paint filly was evaluated because of sudden onset of ataxia that progressed to recumbency. Five additional horses from the same and neighboring premises developed signs of poor performance, generalized weakness, ataxia, and recumbency; 2 of those horses were also evaluated. A new batch of a commercial feed supplement had been introduced to the horses' diet on each farm within the preceding 3 days. CLINICAL FINDINGS: Other than recumbency, findings of physical and neurologic examinations of the foal were unremarkable. The other 2 horses had generalized weakness and mild ataxia, and 1 horse also had persistent tachycardia. The foal had mild leukocytosis with neutrophilia, hyperglycemia, and mildly high serum creatine kinase activity. Results of cervical radiography, CSF analysis, and assessments of heavy metals and selenium concentrations in blood and vitamin E concentration in serum were within reference limits. Feed analysis revealed high concentrations of the ionophore antimicrobial salinomycin. TREATMENT AND OUTCOME: The 5 affected horses survived, but the foal was euthanized. At necropsy, a major histopathologic finding was severe vacuolation within neurons of the dorsal root ganglia, which was compatible with ionophore toxicosis. The surviving horses developed muscle atrophy, persistent weakness, and ataxia. CLINICAL RELEVANCE: In horses, ionophore toxicosis should be considered as a differential diagnosis for acute weakness, ataxia, recumbency, or sudden death. Furthermore, ionophore toxicosis should be considered as a cause of poor performance, weakness, muscle wasting, and cardiac arrhythmias in horses. Surviving horses may have impaired athletic performance. 相似文献
32.
Francis Leo Collins 《Asia Pacific viewpoint》2006,47(2):217-234
Abstract: In recent years, international education has become a source of considerable political, academic and media debate in New Zealand. This is nowhere more the case than with regards to Auckland, the New Zealand city that has hosted the greatest number of international students. This paper focuses on the media debates around international students in Auckland with particular emphasis on the representations of the largest group of international students, those who originate from countries within the North‐East Asian region. The media representations of these students have fixed a diverse group of individuals within a singular racial identity that is known by stereotypical economic, cultural and social characteristics. As a result, these representations have further problematised the interaction between international students and the host population in Auckland while simultaneously implicating a cohort of young New Zealand citizens and permanent residents who are of similar descent within the same discourses. This process of othering the Asian student, regardless of citizenship, has consequences not simply for the practice of exporting education in this city but also for the future of a multicultural Auckland and New Zealand. 相似文献
33.
Growth trials were conducted outdoors in the UK to determine the yield, yield components and plant architectural differences
between determinate and indeterminate Phaseolus vulgaris bean plants. F3 lines derived from crosses between ‘Prelude’, a determinate cultivar and ‘V8’, an indeterminate landrace,
were grown together with the parents and ‘Carioca’, an indeterminate landrace from Brazil. Data were recorded on flowering
date, number of nodes on main stem at flowering, plant height at maturity, number of pods/plant, number of seeds/pod, number
of seeds/plant, 100-seed weight, seed mass/plant, percentages of diseased and healthy seeds/plant. Determinate F3 lines had
significantly lower (P < 0.05) seed mass/plant, fewer pods/plant, fewer seeds/pod, fewer seeds/plant, lower harvest index, shorter stems, earlier
date of flowering, fewer nodes at flowering and fewer healthy seeds/plant than indeterminate F3 lines. However, determinate
genotypes had significantly larger (P < 0.05) pods to accommodate their larger seeds compared with indeterminate lines. A similar situation was found when the
yield and yield components of ‘V8’, ‘Prelude’ and ‘Carioca’ were evaluated; the highest seed mass/plant was given by ‘V8’
and the lowest by ‘Prelude’. Furthermore, some indeterminate genotypes with Type IV growth habit yielded significantly higher
(P < 0.05) than the high-yielding parent, ‘V8’, indicating a positive influence on seed yield by crossing different genotypes. 相似文献
34.
Influence of alpine plants growing on steep slopes on sediment trapping and transport by runoff 总被引:1,自引:0,他引:1
Understanding the interactions between soil and the organisms that are conducive to decreasing sediment runoff is a great concern on high-elevation ski trails. Intense rainfalls on steep slopes combined with soil formed on gypsum result in recurrent erosion. This study was conducted in the northern French Alps to determine the abilities of species: (1) to make mounds and (2) to trap sediment and thereby to control erosion at the slope scale. We also investigated relevant above-ground plant characteristics related to those abilities. Sediment runoff or deposition was investigated at small and large spatial scales. We assessed whether hoof prints in soil reflect sediment runoff at the slope scale by trapping sediment. Populations of plants growing on two slope angles (25° and 35°) and three vegetation cover densities (15%, 35%, 60%) were surveyed. An experiment was also conducted to measure the sediment deposit upslope of target species and over three months during the autumn. Small mounds were found upslope of the plant and sediment deposit measurements showed that they resulted from a sedimentation process. Nevertheless the species differed in their capacity to make mounds. Sesleria caerulea and Festuca alpina had the highest amount of sediment deposition over the experimental period. Among the plant characteristics, plant length was positively correlated with mound area, while the roundness index of the canopy was negatively correlated with mound height. Mound formation was also positively related to the number of tillers or shoots. Sediment accumulation in cow hoof prints was linked to runoff that occurred at the slope scale. Low deposition in hoof prints means low sediment runoff or a large deposition on mounds, due to the increase in vegetation cover. All the findings stressed that understanding the processes in action at larger scales requires studying processes at smaller scales. 相似文献
35.
A S Carman S S Kuan O J Francis G M Ware A E Luedtke 《Journal of the Association of Official Analytical Chemists》1984,67(6):1095-1098
A sensitive, highly selective liquid chromatographic (LC) method is described which uses electrochemical (EC) reduction of the analyte in the determinative step. The method is capable of determining xanthomegnin in mixed animal feeds and grains at levels ranging from 15 to 1200 ng/g. The method can detect as little as 0.5 ng xanthomegnin injected on the LC column. Xanthomegnin is extracted with chloroform and 0.1M phosphoric acid. An aliquot of the crude extract is purified by silica gel column chromatography using a Sep-Pak silica gel cartridge. A novel feature of the method is that xanthomegnin is "backed off" the column by reversing the flow of the eluant through the column. LC is then used to separate xanthomegnin from other interfering substances. Xanthomegnin is detected by EC reduction at -0.16 V. Recoveries of xanthomegnin added to samples at levels ranging from 15 to 1200 ng/g averaged 79% with a coefficient of variation of 7.9%. Results also demonstrate that this LC system can separate the related metabolites viomellein and rubrosulphin from each other and from xanthomegnin and that the same EC detection system can be used to detect these metabolites. 相似文献
36.
Ndung'u MW Kaoneka B Hassanali A Lwande W Hooper AM Tayman F Zerbe O Torto B 《Journal of agricultural and food chemistry》2004,52(16):5027-5031
The crude methanol extracts of the root barks of Turraea wakefieldii and Turraea floribunda were found to show mosquito larvicidal activity against third-instar larvae of Anopheles gambiae sensu stricto. Four new limonoids comprising a vilasininoid 1 and three havanensinoids 2-4 were isolated from the chloroform fractions of the methanol extracts of T. wakefieldii and T. floribunda, respectively. The structures of the compounds were elucidated by NMR spectroscopy. Compounds 1, 2, and 4 had LD50 values of 7.1, 4.0, and 3.6 ppm, respectively, and were more potent than azadirachtin, which had an LD50 value of 57.1 ppm when tested against larvae of A. gambiae. 相似文献
37.
Heat stress adversely affects wheat production in many regions of the world and is particularly detrimental during reproductive
development. The objective of this study was to identify novel quantitative trait loci (QTL) associated with improved heat
tolerance in wheat (Triticum aestivum L.) and to confirm previous QTL results. To accomplish this, a recombinant inbred line (RIL) population was subjected to
a three-day 38°C daytime heat stress treatment during early grain-filling. At maturity, a heat susceptibility index (HSI)
was calculated from the reduction of three main spike yield components; kernel number, total kernel weight, and single kernel
weight. The HSI, as well as temperature depression (TD) of the main spike and main flag leaf during heat stress were used
as phenotypic measures of heat tolerance. QTL analysis identified 14 QTL for HSI, with individual QTL explaining from 4.5
to 19.3% of the phenotypic variance. Seven of these QTL co-localized for both TD and HSI. At all seven loci, the allele for
a cooler flag leaf or spike temperature (up to 0.81°C) was associated with greater heat tolerance, indicated by a lower HSI.
In a comparison to previous QTL results in a RIL population utilizing the same source of heat tolerance, seven genome regions
for heat tolerance were consistently detected across populations. The genetic effect of combining three of these QTL, located
on chromosomes 1B, 5A, and 6D, demonstrate the potential benefit of selecting for multiple heat tolerance alleles simultaneously.
The genome regions identified in this study serve as potential target regions for fine-mapping and development of molecular
markers for more rapid development of heat tolerant germplasm. 相似文献
38.
番茄疮痂病病原菌分类、抗性遗传和分子标记辅助选择进展 总被引:2,自引:0,他引:2
番茄疮痂病是世界上所有番茄种植地区主要的细菌性病害之一,该病能引起严重的产量损失和品质下降,几十年来一直受到育种界的关注。由于该病病原菌存在多个种和小种以及对该病的抗性呈数量性状遗传,因此通过育种途径来改良抗性进展缓慢。分子标记辅助选择为育种家筛选、聚合或累加对多个小种的抗性提供了一种工具。以前的综述对1997年以前在病害的发生、症状、危害、综合防治、遗传分析和育种等方面的研究进行了较为详尽的总结。近年来,在病原菌种与小种的鉴定、抗源的发掘、抗性遗传的分子定位和分子标记辅助选择方面的研究取得了很大进展,传统育种与分子生物学方法有机结合的策略也初见成效。本文将对这些进展进行总结,并对分子标记在番茄疮痂病抗性育种中的应用前景进行讨论。 相似文献
39.
Cui H Cruz-Correa M Giardiello FM Hutcheon DF Kafonek DR Brandenburg S Wu Y He X Powe NR Feinberg AP 《Science (New York, N.Y.)》2003,299(5613):1753-1755
Loss of imprinting (LOI), an epigenetic alteration affecting the insulin-like growth factor II gene (IGF2), is found in normal colonic mucosa of about 30% of colorectal cancer (CRC) patients, but it is found in only 10% of healthy individuals. In a pilot study to investigate the utility of LOI as a marker of CRC risk, we evaluated 172 patients at a colonoscopy clinic. The adjusted odds ratio for LOI in lymphocytes was 5.15 for patients with a positive family history [95% confidence interval (95% CI), 1.70 to 16.96; probability P = 0.002], 3.46 for patients with adenomas (95% CI, 1.14 to 11.37; P = 0.026), and 21.7 for patients with CRC (95% CI, 3.48 to 153.6; P = 0.0005). LOI can be assayed with a DNA-based blood test, and it may be a valuable predictive marker of an individual's risk for CRC. 相似文献
40.
Nojima S Schal C Webster FX Santangelo RG Roelofs WL 《Science (New York, N.Y.)》2005,307(5712):1104-1106
The sex pheromone of the German cockroach, Blattella germanica, has been characterized as gentisyl quinone isovalerate. This cockroach is a major cause of allergic disease and serves as a mechanical vector of pathogens, making it one of the most important residential and food-associated pests worldwide. The sex pheromone-producing gland in adult females was identified in 1993, but thermal instability of the pheromone made characterization difficult. Now, using a new preparative gas chromatography approach coupled with electroantennographic detection, we have isolated and characterized the pheromone, which we term blattellaquinone, and confirmed the identification by chemical synthesis. The synthetic pheromone was active in behavioral assays and highly effective in field trapping tests, which suggest that it may provide a new tool in cockroach population detection, monitoring, and control. 相似文献