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排序方式: 共有493条查询结果,搜索用时 46 毫秒
21.
Lim HS Ko TS Hobbs HA Lambert KN Yu JM McCoppin NK Korban SS Hartman GL Domier LL 《Phytopathology》2007,97(3):366-372
ABSTRACT Transgenic soybean (Glycine max) plants expressing Soybean mosaic virus (SMV) helper component-protease (HC-Pro) showed altered vegetative and reproductive phenotypes and responses to SMV infection. When inoculated with SMV, transgenic plants expressing the lowest level of HC-Pro mRNA and those transformed with the vector alone initially showed mild SMV symptoms. Plants that accumulated the highest level of SMV HC-Pro mRNA showed very severe SMV symptoms initially, but after 2 weeks symptoms disappeared, and SMV titers were greatly reduced. Analysis of SMV RNA abundance over time with region-specific probes showed that the HC-Pro region of the SMV genome was degraded before the coat protein region. Transgenic soybean plants that expressed SMV HC-Pro showed dose-dependent alterations in unifoliate leaf morphologies and seed production where plants expressing the highest levels of HC-Pro had the most deformed leaves and the lowest seed production. Accumulation of microRNAs (miRNAs) and mRNAs putatively targeted by miRNAs was analyzed in leaves and flowers of healthy, HC-Pro-transgenic, and SMV-infected plants. Neither expression of SMV HC-Pro nor SMV infection produced greater than twofold changes in accumulation of six miRNAs. In contrast, SMV infection was associated with twofold or greater increases in the accumulation of four of seven miRNA-targeted mRNAs tested. 相似文献
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The distribution of seabirds west of Scotland was studied relative to water masses in August 1988. Surface salinity was used to indicate the ship's position relative to the water masses described in the literature. Comparisons were made between seabird densities in Inshore Water, the Northern Coastal Current, the Southern Coastal Current and Atlantic/Hebridean Water. Seabird density varied with water mass; some species distributions suggested strong habitat associations. Water masses represent marine habitats, with different physical regimes supporting different marine life; patterns in bird distribution are likely to reflect prey distribution and availability. Manx shearwaters Puffinus puffinus, razorbills Alca torda, guillemots Uria aalge, and kittiwakes Rissa tridactyla were found mostly in Inshore Water, with lower densities in the Northern and Southern Coastal Current water. Only trace numbers of these species occurred in Atlantic/Hebridean Water. Storm petrels Hydrobates pelagicus, fulmars Fulmarus glacialis and puffins Fratercula arctica were found in very low densities in Inshore Water, and were dispersed in higher densities throughout the more oceanic areas. These data suggest that in late summer the Inshore Water of southwestern Scotland has the highest densities of seabirds potentially vulnerable in the event of an oil incident. 相似文献
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Wachira Kaguongo Gladys Maingi Ian Barker Nancy Nganga Joseph Guenthner 《American Journal of Potato Research》2014,91(1):109-118
Although potatoes are the second most valuable crop in Kenya, poor seed potato quality has limited industry expansion. The objectives of this study were to describe the seed potato system, identify problems, determine use of high-quality seed and estimate farmer willingness to pay (WTP) for different types of seed. Data was collected from interviews, forums and surveys. A contingent valuation method (CVM) model was also developed to analyze the factors that influence farmer WTP. It was found that the seed system consists of three sub-components: Formal, Semi-Formal and Farmer. More than 96 % of Kenya seed potatoes were produced in the Farmer category, and were considered to be poor quality. Growers identified bacterial wilt, viral diseases and late blight as the most serious problems. The WTP model revealed that farmer age, distance to seed source, potato training, gender and region were statistically significant explanatory variables. The study recommends that training be conducted to increase production of “clean seed” and “positively-selected seed” in the Semi-Formal part of the seed system. 相似文献
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Tanja Grkovic Johanna S. Blees Magdalena M. Bayer Nancy H. Colburn Cheryl L. Thomas Curtis J. Henrich Megan L. Peach James B. McMahon Tobias Schmid Kirk R. Gustafson 《Marine drugs》2014,12(8):4593-4601
A cell-based high-throughput screen that assessed the cellular stability of a tumor suppressor protein PDCD4 (Programmed cell death 4) was used to identify a new guanidine-containing marine alkaloid mirabilin K (3), as well as the known compounds mirabilin G (1) and netamine M (2). The structures of these tricyclic guanidine alkaloids were established from extensive spectroscopic analyses. Compounds 1 and 2 inhibited cellular degradation of PDCD4 with EC50 values of 1.8 μg/mL and 2.8 μg/mL, respectively. Mirabilin G (1) and netamine M (2) are the first marine natural products reported to stabilize PDCD4 under tumor promoting conditions. 相似文献
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Smarick SD Rylander H Burkitt JM Scott NE Woelz JS Jandrey KE Aldrich J Sturges BK 《Journal of the American Veterinary Medical Association》2007,230(3):370-374
CASE DESCRIPTION: A 9-year-old dog was evaluated for traumatic cervical myelopathy after a surgical attempt to realign and stabilize the C2 and C3 vertebrae. CLINICAL FINDINGS: The dog could not ventilate spontaneously and was tetraplegic; positive-pressure ventilation (PPV) was maintained. Myelography and computed tomography revealed spinal cord compression with subluxation of the C2 and C3 vertebrae and extrusion of the C2-3 intervertebral disk. TREATMENT AND OUTCOME: Surgically, the protruding disk material was removed and the vertebrae were realigned with screws and wire. For PPV, assist control ventilation in volume control mode and then in pressure control mode was used in the first 6 days; this was followed by synchronized intermittent mandatory ventilation until 33 days after the injury; then only continuous positive airway pressure was provided until the dog could breathe unassisted, 37 days after the injury. Physical therapy that included passive range of motion exercises, neuromuscular electrical stimulation, and functional weight-bearing positions was administered until the dog was discharged 46 days after injury; the dog was severely ataxic and tetraparetic but could walk. Therapy was continued at home, and 1 year later, the dog could run and had moderate ataxia and tetraparesis. CLINICAL RELEVANCE: Hypoventilation with tetraparesis in traumatic spinal cord injury can be successfully treated with PPV exceeding 30 days, surgery, and physical therapy. 相似文献
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埃塞俄比亚位于东非高原,具有独特的高原气候条件和丰富的水利资源。目前埃塞俄比亚尚处市场经济发展的起步阶段,外资政策优惠,租赁土地价格低廉,并拥有众多的廉价劳动力。这些都为花卉业的发展提供了难得的条件,产品在国际花卉市场上极具竞争力。 相似文献
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Variation for grain milling energy in Hordeum vulgare is associated with differences in grain size, shape and composition. Genetic polymorphisms within and between populations were found across the ecogeographical range of Hordeum spontaneum in Israel. Low milling energy estimates were positively correlated with and predictable by the aridity index. Milling energy in H. spontaneum, collected in Israel, ranged from the lowest values seen in making barley to twice the highest values seen in feed cultivars. It is concluded that H. spontaneum elite genotypes could be effectively identified by milling energy for use in the breeding of new cultivars. 相似文献