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991.
992.
A one‐year‐old, Thoroughbred colt presented for evaluation due to a one month history of fever of unknown origin and progressive weight loss. On initial presentation, the horse was febrile and showed signs localised to the respiratory tract. These included bilaterally increased bronchovesicular sounds and a moderate, diffuse interstitial pattern on thoracic radiographs. A transtracheal wash yielded mucopurulent debris, culture of which grew small numbers of Staphylococcus epidermidis and Aspergillus spp. The horse was discharged with a diagnosis of bronchointerstitial pneumonia and placed on antibiotic therapy. Ten days after initial presentation, he developed abdominal pain that was unresponsive to on‐farm treatment. The horse was febrile, displayed increased respiratory rate and effort, and showed moderate signs of abdominal pain. On rectal examination, a firm, 8–10 cm mass was palpated on midline. The colt was admitted to the hospital and scheduled for exploratory laparotomy, but died a short time later before surgery could be performed. This report describes the clinical, diagnostic and histopathological findings of a case of alimentary lymphoma in a yearling colt. 相似文献
993.
Responses of swamp bay,Persea palustris,and avocado,Persea americana,to various concentrations of the laurel wilt pathogen,Raffaelea lauricola 下载免费PDF全文
M. A. Hughes S. A. Inch R. C. Ploetz H. L. Er A. H. C. van Bruggen J. A. Smith 《Forest Pathology》2015,45(2):111-119
Laurel wilt, caused by the fungus Raffaelea lauricola and transmitted by the exotic ambrosia beetle Xyleborus glabratus, has killed members of the Lauraceae plant family throughout the southeast United States. A series of experiments were conducted to examine the effects of inoculum concentration on the development of laurel wilt in swamp bay, Persea palustris, and avocado, Persea americana. In each experiment, host plants were inoculated with aqueous suspensions of 102, 103, 104 or 105 conidia of R. lauricola, and plants were rated periodically for external symptom development (wilting and foliar dieback). At the end of experiments, plants were rated for internal symptoms of the disease (discoloration of sapwood) and assayed for R. lauricola on a semi‐selective medium. Symptom severity in swamp bay was significantly lower for the 102 treatment than at higher (103–105) concentrations, whereas 102 and 103 conidia caused less disease than 104 and 105 conidia in avocado. At the lowest inoculum concentration, 67% of the swamp bay plants and 20% of the avocados died by the time the respective experiments were terminated. The pathogen was recovered from a high proportion of the symptomatic sapwood of swamp bay (100%) and avocado (94%), and sapwood discoloration and recovery of R. lauricola from inoculated stems of swamp bay were highly correlated with recovery of the pathogen and symptom development in roots. Clearly, swamp bay and avocado are very sensitive to R. lauricola. The ability of only 100 conidia of this pathogen to kill these hosts suggests that few individuals of X. glabratus or other ambrosia beetles that carry low levels of the pathogen would be sufficient to transmit conidia that infect and lead to disease development. The results are also relevant to the development of disease‐tolerant host selections, as they indicate levels of the pathogen appropriate for use in screening plants for disease resistance. 相似文献
994.
Bao-Luo Ma Zhiming Zheng Joann K. Whalen Claude Caldwell Anne Vanasse Denis Pageau Peter Scott Hugh Earl Don L. Smith 《植物养料与土壤学杂志》2019,182(2):252-264
Balanced plant nutrition is essential to achieve high yields of canola (Brassica napus L.) and get the best economic return from applied fertilizers. A field study was conducted at nine site‐years across eastern Canada to investigate the effects of nitrogen (N), sulfur (S) and boron (B) fertilization on canola nutrient uptake, nutrient balance, and their relationship to canola yields. The factorial experiment consisted of four N rates of 0 (N0), 50 (N50), 100 (N100), and 150 (N150) kg ha?1, two S rates of 0 (S0) and 20 (S20) kg ha?1, and three B treatments of 0 (B0), 2 kg ha?1 at preplant (B2.0P), and 0.5 kg B ha?1 foliar‐applied at early flowering stage (B0.5F). Each site‐year used the same experimental design and assigned treatments in a randomized complete block design with four replications. Fertilizer S application greatly improved seed yields at six out of nine site‐years, and the highest N use efficiency was in the N150+S20 treatment. Sulfur application generally increased seed S concentration, seed S removal, and plant total S uptake, while B fertilization mainly elevated straw B concentration and content, with minimal effect on seed yields. At the early flowering stage, plant tissue S ranged from 2.2 to 6.6 mg S g?1, but the N : S ratio was over or close to the critical value of 12 in the N150+S0 combination at five site‐years. On average across nine site‐years, canola reached a plateau yield of 3580 kg ha?1 when plants contained 197 kg N ha?1, 33 kg S ha?1 and 200 g B ha?1, with a seed B content of 60 g B ha?1. The critical N, S, and B values identified in this work and their potential for a posteriori nutrient diagnosis of canola should be useful to validate fertilizer requirements for canola production in eastern Canada. 相似文献
995.
P.K. Ghosh D.S. Jayas E.A. Smith M.L.H. Gruwel N.D.G. White P.A. Zhilkin 《Biosystems Engineering》2008,100(3):389-400
996.
Rawn DF Quade SC Sun WF Smith M Fouquet A Bélanger A 《Journal of agricultural and food chemistry》2008,56(3):916-921
Apples were sampled directly from orchard trees at 96, 45, and 21 days postapplication with one of three organophosphate insecticides (azinphos methyl, phosalone, or phosmet, respectively). Individual apples were prepared for analysis following one of three postharvest preparations: no preparation, rinsed with deionized water for 10-15 s, or rinsed and peeled. Azinphos methyl, phosalone, and phosmet concentrations ranged from below the level of detection to 5.26 ng/g, 94.7 to 5720 ng/g, and 0.011 to 663 ng/g in the apples that received no postharvest preparation, respectively. Although rinsed apples had lower maximum concentrations than observed in apples with no preparation, levels were not significantly lower. Concentrations of all three OP insecticides in apples that were rinsed followed by peeling, however, were much lower (below detection limits to 0.733 ng/g, azinphos methyl; 0.322-219 ng/g, phosalone; and below detection limits to 44.0 ng/g, phosmet) than observed in apples that had been rinsed alone. Rinsing and peeling of apples resulted in a 74.5-97.9% reduction in OP residues, while rinsing alone lowered mean concentrations by 13.5-28.7% relative to apples that received no postharvest preparation. 相似文献
997.
Centaurea solstitialis, commonly known as yellow starthistle, is an invasive plant listed as a noxious weed in the western areas of North America and is the target of classical biological control, which involves release of herbivores known to be specific to this plant. These insects often choose their host plant on the basis of the volatile organic compounds (VOCs) emitted. Accordingly, volatile analysis of host plants can provide insight into VOCs that may attract and/or repel the insect. To this end, solid-phase microextraction (SPME) and a customized collection bag were utilized to perform in situ volatile collection on intact and mechanically damaged leaves of Centaurea solstitialis, Centaurea cyanus, and Centaurea cineraria. Volatile identification was performed by GC-MS, and the VOC differences were determined. The plants C. solstitialis and C. cyanus have been reported to attract the weevil, Ceratapion basicorne, a candidate for biological control, whereas C. cineraria does not attract the weevil. Major VOCs unique to C. cineraria include the sesquiterpenes cyclosativene, alpha-ylangene, and trans-alpha-bergamotene. The compound trans-beta-farnesene was unique to C. solstitialis and C. cyanus. 相似文献
998.
Cozzolino D Cynkar WU Dambergs RG Mercurio MD Smith PA 《Journal of agricultural and food chemistry》2008,56(17):7631-7636
Samples (n = 620) of homogenized red grape berries were analyzed using a visible and near-infrared (NIR) spectrophotometer (400-2500 nm) in reflectance. The spectra and the analytical data were used to develop partial least-squares calibrations to predict dry matter (DM) content and condensed tannins (CT) concentrations. The coefficient of determination in cross-validation and the standard error of cross-validation were 0.92 and 0.83% w/w for DM and 0.86 and 0.46 mg/g epicatechin equivalents for CT, respectively. The standard error in prediction was 1.34% w/w for DM and 0.89 mg/g epicatechin equivalents for CT, respectively. By implementing a NIR spectroscopy method to measure DM and CT in red grape homogenates, we have developed an approach that is suited to large-scale compositional analysis in commercial wine production facilities, as it enables the analysis of large numbers of samples needed to stream batches of fruit. From an economical point of view, the calibration models could be achieved with relatively small data sets. Thus, NIR offers a suitable and efficient tool for the simultaneous measurement of DM and CT in addition to other important parameters in red grape homogenates such as total anthocyanins, total soluble solids, and pH, with minimal sample preparation and low cost. 相似文献
999.
Kang YH Parker CC Smith AC Waldron KW 《Journal of agricultural and food chemistry》2008,56(18):8558-8564
Carrot cell walls have been shown to contain significant quantities of esterified p-hydroxybenzoic acid, which is presumed to be esterified to cell wall polymers. The purpose of this study was to investigate the distribution of p-hydroxybenzoic acid and related phenolics among carrot cell wall polysaccharides. Cell wall material was prepared from fresh carrot root tissues and extracted sequentially with water, imidazole, cyclohexane- trans-1,2-diamine- N, N, N', N'-tetraacetate, Na 2CO 3, and KOH (0.5, 1, and 4 M) to leave a cellulose-rich residue. The fractions were analyzed for their carbohydrate and phenolic acid components. Selected soluble fractions were subfractionated further by graded precipitation in ethanol. The majority of the polymer fractions comprised pectic polysaccharides, with varying quantities of neutral sugars (arabinose and galactose). Hemicellulosic polymers were generally found only in the strong alkali extracts (4 M KOH). p-OH-benzoic acid was the predominant phenolic ester and was associated with most fractions analyzed; p-OH-benzaldehyde was also detected in the fractions at much lower levels. Principal components analysis of the chemical data indicated that the p-OH-benzoic acid was associated predominantly with the branched pectic polysaccharides, in contrast to the p-OH-benzaldehyde. The possible roles and functional properties of these phenolics are discussed. 相似文献
1000.
Robertson JA Faulds CB Smith AC Waldron KW 《Journal of agricultural and food chemistry》2008,56(5):1720-1726
Analysis of wheat bran and spent grain shows that concentrations of ferulate and diferulates offer considerable scope to modify the cross-linking of feruloylated polysaccharides and hence the mechanical properties of these residues. In solution ferulic acid (FA) can be readily polymerized by horseradish peroxidase, but when esterified to a polysaccharide, the profile of diferulates becomes restricted. This situation also exists in muro and suggests structural constraints may limit the availability of FA for cross-linking. At relatively low polysaccharide concentration, (approximately 3%), steric restrictions were apparent in gels prepared using isolated polysaccharides. Mechanical properties such as swelling also appear to be fixed at these relatively low polysaccharide concentrations. This limits the potential to modify mechanical properties in muro through oxidoreductase activity. To modify mechanical properties such treatments will need to focus on increasing the "flexibility" of the cell wall matrix and the accessibility of enzymes to the cell wall matrix. 相似文献