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21.
Spain CV Scarlett JM Cully SM 《Journal of the American Animal Hospital Association》2002,38(5):482-488
Practicing veterinarians in small-animal or mixed-animal practice in New York state were surveyed about their beliefs and practices regarding the age at which dogs and cats should be neutered and their attitudes toward early neutering (at 4 months of age or younger). The majority of veterinarians routinely recommended neutering for all client animals (70.6%) and supported the routine neutering of shelter animals before adoption (90.3%). More veterinarians in this study reported at least one perceived benefit (91.3%) for early neutering than reported at least one perceived risk (84.4%). Veterinarians with experience neutering early were less likely to believe that the procedure was associated with one or more risks. 相似文献
22.
In a study of the oligochaete fauna and their actinosporean parasites in three lakes in Algonquin Park, Canada, a novel form of raabeia-type actinosporean was observed in a single specimen of Uncinais uncinata (?ersted) (Naididae). This form differs from those previously described in its small size, and by having caudal processes that gradually widen and terminate with a single prominent branch. 相似文献
23.
"Kennel cough" in dogs in animal shelters is readily transmissible, reduces adoption rates, and commonly leads to the euthanasia of affected dogs. In cats, tracheobronchitis, conjunctivitis, and pneumonia have been associated with Bordetella bronchiseptica infection-but most cases of upper-respiratory infection (URI) probably are caused by herpesvirus and calicivirus, and many B. bronchiseptica culture-positive cats are clinically normal. Our prospective observational study was undertaken to document the contribution of B. bronchiseptica to disease in cats and dogs from two animal shelters undergoing outbreaks of canine kennel cough, to evaluate whether cross-species transmission might have occurred, and to determine if the presence of infected cats represented a risk to dogs. Clinically defined cases of kennel cough in dogs and URI in cats were investigated in two shelters by calculating clinical-disease incidence, alveolar-lavage cytological examination, bacterial and viral cultures, antibiotic-susceptibility testing, and molecular fingerprinting by pulsed-field gel electrophoresis.In a 40-cat and 40-dog "no-kill" shelter, the prevalences of culture positivity were 47% for B. bronchiseptica and 36% for calicivirus at the same time as two resident dogs demonstrated clinical cough. When no dogs had kennel cough 3 months later, 10% of cats were B. bronchiseptica-culture-positive and 63% calicivirus positive. In a large traditional shelter, the incidence of kennel cough in dogs increased over 12 weeks to a maximum of 19 cases/week/120 dogs, during which time the culture prevalence was 23% for B. bronchiseptica in dogs and 47% in cats. Three to 6 months before the kennel-cough epidemic, no dogs or cats were B. bronchiseptica positive. Very little genetic variability was detected in isolates from these shelters; all isolates except one corresponded to a single strain type which was identical to the pattern in a vaccine used in these shelters. Isolates from other cats, a horse, a llama, and a sea otter were genetically distinct from the shelter isolates. There was widespread resistance to cephalosporins and ampicillin, but low or no resistance to amoxicillin/clavulanate, trimethoprim-sulfamethoxazole, tetracycline, and enrofloxacin. Greater percent resistance was observed in the traditional shelter than in the no-kill shelter and feline isolates were more likely to be resistant than canine isolates. 相似文献
24.
In the US eradication program for bovine tuberculosis, a definitive diagnosis depends on the isolation of Mycobacterium bovis. However, in some cases bacterial culture is unsuccessful, even though the tissue is considered suspicious by histopathology because granulomatous lesions and acid-fast organisms are present. The purpose of this study was to determine if polymerase chain reaction (PCR) tests on formalin-fixed tissue would successfully identify the organisms observed in suspect lesions from culture-negative animals. Diagnostic laboratory records were used to select paraffin blocks of tissue from 102 ruminants that had suspect microscopic lesions but no bacterial isolation. Sections from these blocks were examined with PCR primers for IS6110 to detect Mycobacterium tuberculosis complex infection, or with 16S ribosomal RNA and IS900 primers for detection of Mycobacterium avium. The PCR tests successfully identified a mycobacterial infection in 58 of 102 tissues, including 41 M. tuberculosis complex and 17 M. avium (11 subspecies paratuberculosis). These results demonstrate that PCR testing of formalin-fixed tissue, in combination with bacterial culture, may increase the effectiveness of laboratory diagnostic efforts to detect and identify the most common mycobacterial diseases of ruminants. 相似文献
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R. Patricia Penilla Janet Hemingway Alma D. López 《Pesticide biochemistry and physiology》2007,89(2):111-117
The relative rates of cytochrome P450 selection in southern Mexican Anopheles albimanus populations were investigated during a 3 years indoor residual house spraying intervention with a pyrethroid (PYR) or DDT, a mosaic of organophosphate (OP)-PYR, and the annual rotation of OP-PYR-carbamate (CARB). This insecticide resistance mechanism, initially evenly spread in the mosquito population, correlated with PYR resistance during the second treated year, when cytochrome P450 contents increased in most villages of the PYR, rotation and mosaic schemes. However, by the third year, mean cytochrome P450 contents declined to susceptible levels in mosquitoes of the rotation and one mosaic group but not in the PYR-treated villages. In DDT-treated villages, a continuous decrement of cytochrome P450 levels occurred since the first treatment year, and susceptible levels were observed at the end of the intervention. Most correlations of cytochrome P450 levels and PYR resistance were lost during the third year, indicating that another mechanism evolved in resistant mosquito populations. 相似文献
28.
林木遗传工程及木质素的生物合成调节(英文) 总被引:1,自引:0,他引:1
林木遗传工程有利于保存林木遗传资源,改善全球气候,减轻自然林的过度采伐和满足人类日益增长的林木产品需求。控制林木真菌、病毒病、虫害和杂草的遗传工程方法正被广泛地研究和应用。尽管转基因林木的历史不长,种类不多,但它有广泛的应用前景。目前,抗除草剂基因、抗虫基因以及和木材质量相关的基因已被分离并应用于林木遗传工程。植物分子生物学和基因组学中的新技术使得高效林木遗传改良成为可能并将促进这些技术的商业化应用。木质素的应用已有一百年的历史,但木质素生物合成的全过程并不完全清楚。有关松树自然突变体和转基因林木的最新研究结果表明,木质素的生物合成是一个可以调节的过程。这些发现对完善木质素的生物合成途径、加深对木质素前体生物合成途径的理解和通过遗传工程改善木材质量有促进作用。本文综述了林木遗传工程在这些领域中取得的一些进展。 相似文献
29.
杉木幼龄林叶片营养元素含量与林木生长的相关性 总被引:3,自引:0,他引:3
本文重点论述丘陵立地条件下 ,1、2代杉木幼龄林高生长、当年高生长、胸径生长与叶片中营养元素N、P、K、Ca、Mg、Cu、Mn、Zn、Fe含量的相关关系 ,进而从林木营养这个角度 ,为提高林木产量、防治地力衰退提供可靠的科学依据。研究结果表明 :2代杉木幼龄林生长与N、P、Mg、Cu、Mn、Fe含量呈密切的正相关。 1代杉木幼龄林生长虽与P、Mg、Cu、Mn、Fe含量呈正相关 ,但复相关系数数值偏低。也就是说土壤养分含量尚没有明显影响 1代杉木幼龄林正常生长 相似文献
30.
工能基因组学:T-DNA介导的基因诱捕和植物基因鉴定(英文) 总被引:2,自引:0,他引:2
拟南芥菜、水稻、蕃茄、土豆、玉米、小麦和大豆的全基因组测序为植物细胞和发育生 物学研究提供了许多有用的信息。基因组学的中心任务是利用这些信息去探索蛋白质的功能 和鉴定与发育有关的重要基因。尽管依赖于毁坏基因和产生可识别的突变表型的经典遗传学 方法仍然是极为成功的基因鉴定方法,借助于报告基因结构,随机插入植物基因组的T-DNA 介导的基因诱捕正发展成为植物细胞和发育生物学研究的极强有力的技术。本文描述了基因 诱捕、启动子诱捕和增强子诱捕在植物生物学中的应用,并且希望这些基因鉴定方法有助于 植物分子生物学家和生物技术工作者的研究。 相似文献