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排序方式: 共有53条查询结果,搜索用时 15 毫秒
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A Junaidi PE Williamson GB Martin MA Blackberry JM Cummins TE Trigg 《Reproduction in domestic animals》2009,44(5):725-734
We tested the effect of dose of GnRH superagonist on pituitary and testicular function in a study with four groups of four male dogs. The Controls received blank implants and the other three groups received implants containing 3, 6 or 12 mg deslorelin (d ‐Trp6‐Pro9‐des‐Gly10‐GnRH ethylamide). In all deslorelin‐treated groups, there was initially an acute increase in plasma concentrations of LH and testosterone, followed by declines such that both hormones became undetectable after approximately 12 days. There was a dose–response in some of these early aspects of the hormone profiles. With respect to long‐term effects of treatment, the 12‐mg dose had significantly greater effects than the smaller doses for the duration of minimum testicular volume [366 ± 77, mean ± SEM (3 mg), 472 ± 74 (6 mg), and 634 ± 59 (12 mg) days], absence of ejaculate [416 ± 88 (3 mg), 476 ± 83 (6 mg), and 644 ± 67 (12 mg) days], undetectable plasma concentrations of LH and testosterone [367 ± 64 (3 mg), 419 ± 72 (6 mg), and 607 ± 69 (12 mg) days], the delay until complete recovery of LH and testosterone secretion [394 ± 65 (3 mg), 484 ± 72 (6 mg) and 668 ± 47 (12 mg) days], and the delay until testes had regrown to normal volume [408 ± 77 (3 mg), 514 ± 74 (6 mg), 676 ± 59 (12 mg) days]. The time taken to restore full ejaculates was also longest for the 12‐mg dose: 716 ± 67 (12 mg) days vs 440 ± 66 (3 mg) and 538 ± 83 (6 mg) days after implantation. There was no correlation between delay to recovery of normal ejaculate quality and body mass. We conclude that the dose–response relationship with deslorelin implants is not expressed with respect to the degree of suppression of reproduction, but on the maximum duration of suppression and thus to delay until recovery. 相似文献
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Maria Cristina Ossiprandi Mirko Buttrini Ezio Bottarelli Laura Zerbini 《Comparative immunology, microbiology and infectious diseases》2010,33(6):e25-e29
Clostridium difficile, associated with a wide spectrum of diseases in humans, as well as in several animal species, is an important cause of colitis in adult horses and foals. The aim of this study was to investigate by toxin gene profile and PCR-ribotyping the molecular characteristics of 14 C. difficile strains isolated from 42 faeces of healthy horses. Both toxin genes, tcdA and tcdB, were present in only 1 isolate (7.1%). Six isolates (42.9%) demonstrated tcdA−/tcdB+ genotype, and seven isolates (50.0%) were tcdA−/tcdB−. All strains were binary toxin genes negative (cdtA−/cdtB−). The PCR-positive strains, except for the tcdA+/tcdB+ isolate, tested negative for, in vitro, A and/or B toxins production by EIA. Eleven distinct ribotypes were observed.In conclusion, C. difficile can be present in the normal intestinal flora of healthy adult horses, in addition to foals. These animals could therefore play an important role as potential reservoirs of toxigenic strains. 相似文献
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The olive industry generates residues which can be applied as amendments to soils in their original form (olive cake) or after composting or vermicomposting processes. The addition, fresh or incubated, of these amendments to soil and of their different organic fractions was studied in relation to the sorption/desorption of three sulfonylurea herbicides, bensulfuron‐methyl, chlorsulfuron and prosulfuron. Herbicide sorption was low or very low, slightly promoted by the addition of the agricultural by‐products, especially olive cake, and mainly affected by pH of the soil solution, with the organic carbon content having no significant effect on herbicide retention. Desorption was only reduced when fresh olive cake was added. The incubation of soil and amendments for 3 months did not modify herbicide sorption, but made desorption reversible except for olive cake. The transformation of the organic matter of the amendments due to humification and maturity processes are likely to be responsible for this behaviour. Different organic fractions were removed to assess the influence of each fraction on sulfonylurea sorption. Only the removal of all studied organic fractions increased herbicide sorption, revealing the role of humin and mineral fractions in this process. Therefore, the use of organic amendments is not useful for reducing the risk of movement of ionisable molecules in soil. 相似文献
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A. A. M. Al‐Shihi A. J. Khan S. Akhtar A. T. M. Lima F. M. Zerbini R. W. Briddon 《Plant pathology》2014,63(5):1177-1184
Whitefly‐transmitted begomoviruses are the most important limiting factor for tomato cultivation in Oman, particularly in the Al‐Batinah region, the major agricultural area of the country. Commercial farms in the Al‐Batinah region were surveyed during January–March 2013. Samples of tomato showing leaf curl disease symptoms typical of begomoviruses were collected and analysed. Full‐length sequences of five clones were shown to have relatively low percentage identity values to known begomoviruses, with the highest (88·6%) to isolates of Tomato leaf curl Oman virus (ToLCOMV), a begomovirus previously reported in Oman, indicating that these represent a newly identified species, for which the name Tomato leaf curl Barka virus (ToLCBrV) is proposed. Four isolates of ToLCBrV were found associated with Tomato leaf curl betasatellite (ToLCB). The five isolates of ToLCBrV characterized in this study were shown to be recombinants, with ToLCOMV as the major parent, and a fragment of Croton yellow vein virus (CrYVV) spanning the 3′ half of the replication‐associated protein. The significance of these findings is discussed. 相似文献
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Long-term agroecosystem experiments: assessing agricultural sustainability and global change 总被引:3,自引:0,他引:3
PE Rasmussen KWT Goulding JR Brown PR Grace HH Janzen M Korschens 《Science (New York, N.Y.)》1998,282(5390):893-896
Long-term agroecosystem experiments can be defined as large-scale field experiments more than 20 years old that study crop production, nutrient cycling, and environmental impacts of agriculture. They provide a resource for evaluating biological, biogeochemical, and environmental dimensions of agricultural sustainability; for predicting future global changes; and for validating model competence and performance. A systematic assessment is needed to determine the merits of all known experiments and to identify any that may exist in tropical and subtropical environments. The establishment of an international network to coordinate data collection and link sites would facilitate more precise prediction of agroecosystem sustainability and future global change. 相似文献
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“楚源果业”(长沙楚源果业有限公司的简称)从2003年起开始实施湖南省优质鲜食猕猴桃产业化工程。公司按照产业化经营的思路和集中成片、规模发展的原则,选择丰悦、翠玉等优良品种,在省内旅游区周边交通便利、农业生产管理水平较高的中低海拔地区建立生产基地,并以公司为龙头,按行业协作组织的形式将各生产基地组织起来,统一技术管理和果品营销。现已建立产业化基地约200hm^2,并在湘中、湘北、湘西北及湘西建立了鲜食猕猴桃重点示范基地。两年来,湖南省优质鲜食猕猴桃产业化开发从无到有,从小到大,极大地促进了湖南省猕猴桃产业的整体发展。 相似文献