猪圆环病毒2型ORF2基因及其编码蛋白的研究概况

结合国内外对猪圆环病毒2型(porcine circovirus2,PCV2)的研究,重点对猪圆环病毒2型ORF2基因及其编码蛋白的抗原表位和功能应用研究进行简要综述,为猪圆环病毒2型新型疫苗研究和建立诊断检测方法研究方面提供参考。     

猪圆环病毒的危害与净化

猪圆环病毒是圆环病毒科圆环病毒属的DNA病毒,根据其基因型的不同可分为1型猪圆环病毒和2型猪圆环病毒。1型猪圆环病毒通常不会对猪造成任何危害,而2型猪圆环病毒则具有较大的致病性。该病毒不仅与猪细小病毒病和繁殖障碍综合症等多种疾病存在一定的相关性,同时可引发猪的肠炎以及间质性肺炎等多系统功能障碍性疾病,给生猪养殖业造成巨大的经济损失。因此,做好猪圆环病毒的净化工作具有非常重要的现实意义。     

东北虎豹国家公园猪圆环病毒病空间分布预测

猪圆环病毒病是由圆环病毒感染引起的猪的多系统功能障碍性疾病,严重危害猪的免疫功能生长发育和生产性能。为系统了解猪圆环病毒病在东北虎豹国家公园内的风险水平,本研究通过建立最大熵模型、使用主成分分析等方法,探究猪圆环病毒病在东北虎豹公园的高发区域分布以及环境因子与猪圆环病毒病暴发之间的关系,寻找影响猪圆环病毒病暴发的环境因素,为该地区猪圆环病毒病的预防和控制提供依据。研究表明,猪圆环病毒病风险分布与降水量呈负相关,影响模型的主要环境因素包括Bio 5（最热月的最高温度）、Tmax11(11月最高温度)以及Bio19（最冷季节降水量）,其中Bio 5以及Tmax11累计贡献率达83.1%。     

猪圆环病毒分子生物学研究进展

猪圆环病毒(porcine circovirus,PCV)是迄今发现的最小的动物病毒,对养猪业造成的损失日趋严重.主要对猪圆环病毒的基因组、致病基因、病毒受体等进行综述,旨在为猪圆环病毒的研究和猪圆环病毒病的预防提供参考.     

猪圆环病毒Cap蛋白亚单位疫苗研究进展

猪圆环病毒病是由猪圆环病毒(PCV)引起的猪的一种多系统功能障碍性疾病,预防该病的有效方法是采用疫苗进行预防接种,除了传统的灭活疫苗外,国内外学者正在积极研究开发PCV2的亚单位疫苗、DNA疫苗以及基因工程活载体疫苗,本文结合国内外对猪圆环病毒亚单位疫苗的研究结果,以抗原蛋白表达系统分类对其研究情况作一综述。     

Ⅱ型猪圆环病毒病研究进展

猪圆环病毒病是近几年新发现的一种猪的传染病,由猪圆环病毒（Porcine Circovirus,PCV2）引起猪的一种多系统功能障碍性疾病。该病原体已被确认为圆环病毒（PCV2）,研究表明,Ⅱ型猪圆环病毒（PCV2）不仅是断奶仔猪多系统衰竭综合症（PM-WS）的病原,而且能够引起多种猪病,     

猪圆环病毒2型PCR快速检测方法的建立

根据GenBank公布的猪圆环病毒2型保守序列设计了一对引物,建立了检测猪圆环病毒2型PCR方法,并对其特异性、敏感性进行了研究。该PCR方法对猪圆环病毒2型的扩增结果为阳性,而对对照毒株的扩增结果均为阴性;对猪圆环病毒2型检测的灵敏度为1pg总DNA量。以上结果表明该PCR方法特异性强、敏感性高、简便、快速,可用于猪圆环病毒2型的早期确诊和病毒鉴定。     

猪圆环病毒病研究进展

猪圆环病毒（PCV）病是近几年新发现的一种猪的传染病,由猪圆环病毒（PCV）引起猪的一种多系统功能障碍性疾病。猪圆环病毒病临床上以断奶仔猪多系统衰竭综合征（PMWS）等为主要特征,该病原体已被确认为猪圆环病毒Ⅱ型（PCV2）。研究表明,猪圆环病毒Ⅱ型不仅是断奶仔猪多系统衰竭综合征（PMWS）的病原而且能够引起多种猪病,主要有新生仔猪先天性脑震颤、猪皮炎及肾衰综合征、     

猪圆环病毒病研究进展

<正>猪圆环病毒(PCV)病是近几年新发现的一种猪的传染病,由猪圆环病毒(PCV)引起猪的一种多系统功能障碍性疾病。猪圆环病毒病临床上以断奶仔猪多系统衰竭综合征(PMWS)等为主要特征,该病原体已被确认为猪圆环病毒Ⅱ型(PCV2)。研究     

PCR快速检测猪圆环病毒2型的方法建立及应用

根据GenBank公布的猪圆环病毒2型保守序列设计了一对引物,建立了检测猪圆环病毒2型的PCR方法,并对其特异性、敏感性进行了研究.该PCR方法对猪圆环病毒2型扩增结果为阳性,对照毒株扩增结果均为阴性;对猪圆环病毒2型检测的灵敏性为1pg总DNA量.结果表明,该PCR方法特异性强、敏感性高、简便、快速,可用于猪圆环病毒2型的早期确诊和病毒鉴定.     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein     

Avian brood parasitism — a growing research area in behavioral ecology (part Ⅱ)

正We are pleased to publish the second special issue on avian brood parasitism and to be responsible guest editors for the two special issues of Chinese Birds (Vol. 3, No. 4, 2012 and Vol. 4, No. 1, 2013), entitled "Avian Brood Parasitism - A Growing Research Area in Behavioral Ecology". The first issue was published in December 2012. The goal of the two special issues is to publish accumulated knowledge and some of the recent developments in