猪戊型肝炎病毒分子生物学与流行病学研究进展

戊型肝炎病毒(Hepatitis E virus,HEV)是20世纪80年代发现的又一新型肝炎病毒,近年来对戊型肝炎病毒病原学、流行病学、实验室诊断、基因结构等方面研究取得了重大进展,本文就HEV的形态、基因分型、分子生物学特性、戊型肝炎(Hepatitis E,HE)的流行病学特点作一简要概述。     

应用PCR诊断隐孢子虫病

应用聚合酶链反应（ Ｐ Ｃ Ｒ）建立了一种诊断人及牛等哺乳动物隐孢子虫病的方法。试验采用甘油漂浮 Ｇ３ 耐酸漏斗过滤法纯化隐孢子虫卵囊,以液氮冻融法制备模板 Ｄ Ｎ Ａ,根据隐孢子虫 １８ Ｓｒ Ｒ Ｎ Ａ 序列设计 Ｐ Ｃ Ｒ 引物建立其诊断方法。该方法特异性强,可检出鼠隐孢子虫（ Ｃｒｙｐｔｏｓｐ ｏｒｉｄｉｕｍ ｍ ｕｒｉｓ）和小球隐孢子虫（ Ｃ．ｐａｒｖｕｍ ）卵囊;敏感性高,每克粪便可检出 ４００ 个卵囊。初步应用结果表明,所建立的 Ｐ Ｃ Ｒ 方法适合于人、牛等哺乳动物隐孢子虫病的临床诊断和流行病学调查。     

新城疫活疫苗对控制鸡大肠杆菌病的效果观察

为了研究鸡新城疫活疫苗紧急免疫控制鸡大肠杆菌病的效果,通过大肠杆菌人工感染30日龄蛋鸡,待出现病症后,紧急免疫新城疫La-sota弱毒苗(Ⅳ系)4羽份.免疫后5～17 d,通过血凝抑制试验测定血清新城疫抗体水平,试验组新城疫抗体水平逐步提高,对照组抗体略有下降,免疫后17 d两组抗体水平差异显著(P＜0.05);对照组...     

二丁酰环腺苷酸的合成与性质研究

以ATP为原料采用化学方法合成了dbcAMP及其钠盐 ,并对其理化性质和吸收特性进行了研究。经质谱分析 ,其结构为C18H2 3 N5O8PNa ,分子量为 4 90 .0 ;经紫外光谱测定其含量为 96 .0 % ,产品的得率为 85 .6 %。dbcAMP钠盐为白色粉末 ,可溶于水与乙醇 ,对热和酸碱比较稳定。经饲料添加和皮下注射dbcAMP检测其经消化道和皮下吸收的性能。通过测定饲喂和皮下注射dbcAMP后 0 .5h、1～ 96h不同时间内血液dbcAMP的浓度表明 ,饲料添加在 3h内达到最大浓度 84 .75pmol/mL ,皮下注射在 2h内达到最大浓度 92 .96pmol/mL ,之后血液中dbcAMP的浓度逐渐下降 ,在 96h达到较低水平。     

单一或复合植物精油添加对麻黄肉鸡生长性能、肉品质和抗氧化能力的影响

本试验旨在研究饲粮中添加植物精油对麻黄肉鸡生长性能、屠宰性能、肉品质和抗氧化能力的影响。选取360只1日龄健康、体重均一的雌性麻黄肉鸡,随机分为3个组,分别为对照组、单一植物精油组（EO1组）和复合植物精油组（EO2组）,每组8个重复,每个重复15只鸡。试验期分为3个生长阶段,分别为1～21日龄、22～42日龄和43～65日龄,共计65 d。对照组饲喂基础饲粮;EO1组在1～21日龄时饲喂基础饲粮+300 mg/kg植物精油1（主要成分为肉桂醛）,在22～65日龄时饲喂基础饲粮+400 mg/kg植物精油1; EO2组饲喂基础饲粮+150 mg/kg植物精油2（主要成分为肉桂醛、香芹酚和百里香酚）。结果表明：与对照组相比,各试验组肉鸡各阶段平均日增重、平均日采食量和料重比均无显著差异（P>0.05）;21日龄时,EO2组肉鸡血清总抗氧化能力显著高于对照组和EO1组（P<0.05）;65日龄时,EO2组肉鸡血清总超氧化物歧化酶活性显著高于对照组（P<0.05）;65日龄时,EO2组肉鸡胸肌红度值显著低于对照组和EO1组（P<0.05）。综上所述,饲粮添加复合植物精...     

封育对云南马龙县退化山地草甸植物量的影响

以云南省马龙县山地草甸为研究对象,对封育3年的退化草地地上植物量和地下植物量的变化进行了测定和分析。结果表明,各退化梯度的草地在封育3年后均得以不同程度的恢复,但草地恢复效率差异很大,按草地恢复效率大小排序结果为：重度退化〉中度退化〉轻度退化。封育明显提高了退化草句群落的地上、地下植物量,各退化梯度草地封育区地上植物量增加速度排序为：重度退化〉轻度退化〉中度退化;各退化梯度封育区地下植物量增加速度排序为：重度退化〉中度退化〉轻度退化。     

山羊子宫内肽能神经分布及妊娠时的变化

采用免疫组化方法，研究了山羊子宫内含P物质（SP）和含血管活性肠肽（VIP）神经的分布。结果，妊娠及未妊娠山羊子宫颈内有粗细不等的神经束行经于外膜和肌层中，神经分支形成丛状分布于血管壁，子宫颈部未见SP神经元胞体及VIP神经元胞体；未妊娠山羊子宫角内SP神经和VIP神经均呈丛状围绕血管并分布于血管壁；妊娠中期的孕角和非孕角均有胎盘形成，除胎盘内无神经分布外，SP神经及VIP神经同样分支形成丛状分布于血管壁。结果提示，山羊子宫内SP神经和VIP神经主要支配子宫内血管，妊娠时除胎盘内无神经分布外，SP神经及VIP神经的分布无明显变化。     

Influence of Ammoniacal Copper Quaternary treatments on mechanical properties of blue-stained Lodgepole Pine wood

Three concentrations （2.8%, 2.0%, 1.2%） of Ammoniacal Copper Quaternary （ACQ） was selected to treat Lodgepole pine wood for evaluating ACQ treatment on mechanical properties of blue-stained wood. The bending modules of elasticity （MOE）, modules of rupture （MOR）, toughness and shearing strength parallel to grain on tangential surface, are tested according to the criteria GB1927-1943-91. Non-treated sample were also tested according to the same procedure. The results showed that the three groups specimen impregnated by different concentrations of ACQ solution met the AWPA standard 2003 of America （UC4A 6.4g/cm^3）. There were significant difference of toughness between treated wood and non-treated wood （p=0.01）, but there were no statistically significant differences among three concentrations in terms of toughness, and toughness of treated wood was approximately 20% lower than non-treated. MOR, MOE as well as sheafing strength parallel to grain were found to be not significantly different between treated wood and non-treated one, and there were no statistically significant difference among three concentrations of ACQ too. Toughness, MOR, MOE and sheafing strength parallel to grain increased with decrease of concentration of ACQ, but they were hardly affected by ACQ preservatives.     

Farm Forestry Prospects Among Some Local Communities in Rachuonyo District,Kenya

Deforestation and degradation of productive lands are serious threats to the sustainability of forestry/agricultural practices in Kenya. In the last two decades farm forestry (FF) has been promoted through pilot projects among local communities as an example of sustainable land use. However adoption of FF is limited outside the project locations because FF improvement measures focused mainly on biological (e.g. succession, biodiversity and traditional industrial timber production) and technical concerns (e.g. material input delivery such as providing free tree seedlings for field planting) rather than local values, and interests and the constraints facing farmers. This study examined the local farm priorities and constraints and the prospects for the wider implementation of farm-level tree planting in four communities in Rachuonyo District. Using interviews with 597 randomly selected household heads, the study assessed farmer’s production assets and activities, land tenure, priority tree species and the constraints to growing trees on farms. Results show that farm labour is represented by a young population, 56.3% under the age of forty. They are mainly engaged in small-scale mixed cropping integrated with multipurpose trees and some livestock. Tree products contribute about 32% to household cash income, more than any other source (agricultural products, labour sales, etc). Females were more often household heads and had considerable influence over productive activities, making them an important target group in FF development. Farmers preferred exotic tree species due to their ability to provide short-term cash income, fuel and shade. Farmers’ concerns included population pressure on limited farmlands and the problem of credit for agricultural inputs. Given the feeling of secured tenure arrangement and influence of tree products on the household economy, farmers are likely to invest more in efficient land uses such as FF if consideration is given to local priorities.     

Using leaf tip necrosis as a phenotypic marker to predict the presence of durable rust resistance gene pair <Emphasis Type="Italic">Lr34</Emphasis>/<Emphasis Type="Italic">Yr18</Emphasis> in wheat

Fifty wheat varieties along with Jupateco-73 and Morocco were studied for the expression of leaf tip necrosis (LTN), a trait linked with the durable rust resistance gene pair Lr34/Yr18. LTN was frequent (i.e., ≥6) in nine replications of a field experiment over 3 years in 17 genotypes, and the varieties were considered positive for LTN. In molecular analyses of these varieties, having relative severity values up to 78 for yellow rust and 45 for leaf rust, the 150-bp Lr34/Yr18-linked allele was consistently amplified. Expression of LTN in six of nine replications is an appropriate threshold for predicting the presence of Lr34/Yr18 gene pair, and genotypes can be selected using this trait.