紫茎泽兰潜在分布对气候变化响应的研究

紫茎泽兰的生态适应性强,是我国外来入侵物种中危害最为严重的恶性杂草。研究紫茎泽兰的适生性特征及对全球气候变化的响应规律是制定防控策略的重要基础,为此,本研究采用了将生态位因子分析(ENFA)与最大熵模型(MaxEnt)嵌套的方法,首先通过ENFA对环境因子进行降维,利用降维后的环境因子以及当前及A1b情景的未来气候数据,根据最大熵模型(MaxEnt)预测紫茎泽兰的潜在分布,并使用ROC曲线分析对预测结果进行评价。结果显示,当前气候情景下,紫茎泽兰的分布区以云南、贵州、广西等省为主;未来A1b情景下,易入侵等级(入侵概率为0.6~1.0)的区域面积将会由当前的12.82 km²增加至2080s的21.30 km²,中心点将由当前位置向西南方向移动61 km;而其中高入侵概率等级(入侵概率为0.8~1.0)的区域面积将由当前的0.42 km²增加至2080s的0.91 km², 中心点将由当前位置向东南方向移动178.66 km。根据当前及未来A1b气候情景下紫茎泽兰潜在分布情况,并根据不同入侵等级区域采取相应的防除治理措施,将对紫茎泽兰的综合治理具有重要指导意义。     

Detection of Serotypes and Virulence Factors of Escherichia coli from Piglets in Beijing

To investigate the cause of piglets diarrhea, and the distribution of the serotype and virulence factors of swine Escherichia coli in Beijing, 400 diarrhea samples were collected. TSA serum agar culture method was used to isolate Escherichia coli, serotype identification test and virulence factor genes test were used to verify the presence of O-antigen. 64 strains of E.coli were isolated from 400 diarrhea samples, among which 42 strains of E.coli were classified as 8 serotypes:O101(18.7%),O64(12.5%),O8(10.9%),O20(10.9%),O45(4.7%),O149(4.7%),O2(1.6%) and O89(1.6%), and the major virulence factors were STa, Stx2e, astA and eaeA. There were 8 mainly serotypes that caused piglets diarrhea in Beijing area, among which O101 serotype accounted for the highest proportion. The major virulence factors were astA and eaeA, accounted for more than 50% of all strains, STa and Stx2e accounted for more than 30% of all strains. These data would provide effective data to support the prevention and control of piglet diarrhea in Beijing.     

Isolation and Identification of Variant HeNZK-2014 of Pseudorabies Virus and Sequence Analysis of gE Gene

In order to learn the situation of pig pseudorabies virus (PRV) variant in this study, tissue samples such as lymph nodes which were collected from clinical pigs with suspected PRV infection were identified by PCR. PRV positive sample were inoculated on PK-15 cells after grinding and degerming, with further experiment including virus isolation, plague purification, PCR and IFA identification, TCID₅₀ confirmed by Reed-Muench method, inoculation test and observation of clinical symptoms in mice. The gE gene of purified PRV and brain tissue samples of dead mice were identified by sequencing analysis. The results showed that the virus grown on PK-15 cells could produce typical cytopathic effect (CPE) after 24 h; After three rounds of plaque purification,the isolate was PRV positive identified by PCR and IFA, and nominated as HeNZK-2014; The TCID₅₀ of the isolate was 10^-9.77/0.1 mL; The virus in 1×10⁸ TCID₅₀ inoculation was able to cause itching, tearing, death in infected mice, and PRV could be detected in tissues of dead mice; The molecular genetic variation analysis of gE gene by PCR amplification and clone sequencing indicated that the gE gene from brain tissue of infected mice shared 100.0% homology with HeNZK-2014, and located in a relatively independent branch with newly pandemic isolates in recent years after 2011, but was far from the classical strains before 2011, and both had two insertion of aspartic acid (D) at sites of 48 and 496 amino acids, which were considered to be the typical characteristics of PRV variants. This study successfully isolated a PRV variant, which laid a foundation for further research on vaccine development, prevention and control against PRV variants.     

牛TLR4基因的遗传多态性与乳房炎的关联分析

TLR4通过识别病原体而激活免疫细胞，在先天免疫和适应性免疫防御中起着重要作用。以中国荷斯坦奶牛、三河牛和中国西门塔尔牛共397头为研究对象，利用创造酶切位点PCR法扩增243bp的目的片段，通过限制性内切酶HinfⅠ酶切来检测TLR4第3外显子的多态性，结果发现扩增产物的27bp处C到T的突变使得多态位点产生，编码的氨基酸由苏氨酸变为异亮氨酸。A、B2个等位基因在3个群体中均有分布，A等位基因占优势（大于78％），经χ^2适合性检验，三河牛在该位点未达到Hardy-Weinberg平衡状态（P〈0．05）。运用SAS8．2软件采用最小二乘法拟合线性模型，将该基因座不同基因型与奶牛乳房炎进行了关联分析，结果表明：AA基因型为乳房炎抗性基因型（P〈0．05），A等位基因为乳房炎抗性的有利基因。     

共轭亚油酸对五龙鹅生长发育和脂质代谢的影响

1日龄五龙鹅192只，随机分为4个处理，分别饲喂共轭亚油酸（CLA）水平为0．0、5．0、15．0和25．0g／kg的日粮，通过测定不同生长阶段的体增重（BWG）、采食量（FI）、料重比（F／G）、腹脂率（AFP），以及与脂质代谢有关血清生化指标，研究不同水平CLA日粮对五龙鹅生长发育和脂质代谢的影响。结果表明：在日粮中分别添加5．0g／kg和15．0g／kgCLA，对五龙鹅BWG无显著影响（P〉0．05），能够显著降低FI和F／G（P〈0．05）；显著降低AFP和血清甘油三酯（TG）、胆固醇（TC）、极低密度脂蛋白（VLDL）含量（P〈0．05或P〈0．01），增加了血清高密度脂蛋白胆固醇（HDL-C）含量和高、低密度脂蛋白胆固醇之比（HDL-C／LDL-C）（P〈0．05）。日粮中添加25．0g／kgCLA，极显著地降低了FI和AFP（P〈0．01），对血清TG、TC、HDL-C、VLDL含量和HDL-C／LDL-C的影响差异不显著（P〉0．05）。适宜添加CLA对五龙鹅的生长发育和脂质代谢具有很好的促进和调节作用，即在五龙鹅的整个生长期内，CLA添加量不高于15．0g／kg时，不但能在不影响BWG的前提下提高饲料利用率，而且能够通过降低脂肪沉积和调节脂质代谢起到预防动脉粥样硬化的作用；但过多添加CLA（25．0g／kg）会使五龙鹅的生长发育受到抑制。     

猪附红细胞体PCR-微孔板杂交-酶免疫检测方法的研究

以猪附红细胞体和多种血营养菌16S rRNA基因的保守区设计合成引物HM-f/HM-r,在反向引物的5′端用生物素标记,以猪附红细胞体广东株16S rRNA基因的可变区序列设计种特异性寡核苷酸探针,探针的5′端用地高辛标记,成功地建立了猪附红细胞体PCR-微孔板杂交-酶免疫检测方法。通过测定不同浓度PCR产物对应的微孔板杂交-酶反应显色OD值,用SPSS统计软件进行回归分析,得到回归方程为y=2.1012-0.4492×logx,其相关系数R为0.977,显示对未知样品可进行定量检测。该方法与猪的多种细菌性病原、猫血巴尔通氏体CA株和E.wenyonii无交叉反应,其敏感性比常规PCR琼脂糖电泳检测提高了近100倍。用建立的方法对38份临床样品进行检测,结果有12份检测结果为阳性。     

牛冷冻精液质量评估研究进展

人工授精(AI)是第一代动物繁殖生物技术,最近几十年以来,研究人员已经探索出了许多评估冷冻-解冻后精液品质的新技术。由于精子质膜在低渗条件下的功能状态、离子分布及浓度和各种细胞器的功能都与冷冻解冻后精子的存活能力相关,冻精质量的评定也从最初的形态和主观活率分析,发展到更精确的染色质、质膜完整性及分解代谢活性的分子变化分析。但是,在实际应用当中,许多方法花费很大,况且单个的评估参数都与动物精子实际的受精力相关性不强。因此,要提高牛冻精质量的预言强度,应该将这些独立的参数结合起来,利用多元回归分析,建立一套更完美更精确的评估体系。     

基于MODIS数据的中国草地生态体系价值估算研究

在传统的草原生态系统价值估算的基础上,利用遥感技术,以谢高地等人计算出来的各种草地类型单位面积价值量为经济参数,利用2003年MODIS数据估算的中国草原生态系统服务价值约折合US$311.48×108,并从草地类型和省区等角度分别进行区域分析,表明我国草原生态系统服务价值呈现出农牧交错带较高且逐渐向牧区递减的特征,说明牧区草原生态系统退化比较严重,草原生态功能保护意识需要进一步加强。     

钠离子对仔猪小肠刷状缘膜囊二肽跨膜转运的影响

为研究Na 在仔猪小肠Gly-Pro跨膜转运中的作用,采用同位素示踪及体外孵育技术,观察在不同Na 浓度梯度条件下Gly-Pro在仔猪小肠刷状缘膜囊(brush border membrane vesicles,BBMV)的跨膜转运量。结果表明:(1)用K 替代Na ,并没有降低Gly-Pro在BBMV中的转运量,在孵育前20min时间内,Gly-Pro的转运量稍稍提高;(2)Na 可使BBMV对L-丙氨酸的转运量提高到4.6倍,但不影响Gly-Pro的转运;二氢骆驼蓬碱显著地降低L-丙氨酸的转运,但对Gly-Pro的转运无影响。研究提示,Gly-Pro在仔猪小肠BBMV体系中的转运与Na 不存在依赖性的关系。     

海西州天然草地产草量地面监测报告

通过对草地产草量的调查和测定,海西州天然草地产草量2005年、2006年基本属于正常年范畴。经草畜平衡分析,2006年全州草地理论载畜量为265.45万羊单位,草地现有载畜量为280.162万羊单位,超载14.71万羊单位。