间接ELISA法研究嗜水气单胞菌对鳗鲡表皮黏液的黏附特性

采用间接ELISA法研究菌浓度、孵育时间、温度、pH、阳离子及碳源等因子对嗜水气单胞菌(Aeromonas hydrophila)黏附鳗鲡(Anguilla anguilla)表皮黏液的影响。结果表明, 改良后的间接ELISA法的检测灵敏度约为9.92×10⁴ CFU, 细菌的黏附量随菌浓度的升高而逐渐增大并符合饱和黏附动力学方程: y=0.135ln(x)-0.936(R²= 0.986); 嗜水气单胞菌黏附鳗鲡表皮黏液的最佳条件为: 温度20~28℃, pH 6.2~6.6, NaCl、MgCl₂质量浓度分别为15~25 g/L和3 g/L, 孵育时间为150 min。碳源对嗜水气单胞菌的黏附作用有不同程度的影响, 葡萄糖和麦芽糖能显著提高嗜水气单胞菌的黏附量(P<0. 05), 果糖则显著降低嗜水气单胞菌的黏附量(P<0. 05)。以上结果说明, 嗜水气单胞菌对鳗鲡表皮黏液具有较强的黏附作用, 且其黏附作用具有可控性。

     

Epidermal proteases of the Japanese eel

A fluorescent-sensitive assay was used to demonstrate the protease activity in the dorsal skin of Japanese eel (Anguilla japonica). Two distinct extracts were separately prepared from skin mucus and epidermal cell layers, with no mutual contamination. The epidermal extract was sensitive to various substrates, whereas there was no, or only marginal, susceptibility to the same substrates for the mucous extract. Optimum hydrolysis pHs of the epidermal extract was variable and below pH 7.0, and the optimum hydrolysis temperatures were between 40 and 50 °C. In addition, Tos-Phe-Ch₂Cl, chymostatin, CdCl₂, CuCl₂, HgCl₂ and ZnCl₂ inhibited protease activities to different extents. Several other reagents specifically affected the protease activities, and their induced effects were useful for the identification of epidermal proteases. The findings indicate that a proteolytic factor, exhibiting various enzymological specificities, is retained within epidermal cell layers of Japanese eel. This factor is composed of 4 distinct proteases, such as cathepsins L and B-like proteases, a serine protease and an aminopeptidase.     

The Ecological Concept of Costs of Induced Systemic Resistance (ISR)

Plant defence is thought to provide benefits for the defended plants. Theoretical concepts must, therefore, explain why there is variation in defensive traits, which naively might be assumed to be present constitutively in fixed high amounts. Explanations are mainly based on the assumption of fitness costs. Investment in defence is thought to reduce the fitness of plants in enemy-free environments. Fitness costs often result from allocation costs, i.e. allocation of limited resources to defence, which then cannot be used for growth or other fitness-relevant processes. This theoretical concept can provide a useful tool for the interpretation of induced plant responses against pathogens, named induced systemic (or systemic acquired) resistance (ISR or SAR). Phenotypic plasticity, leading to induced responses, might have evolved mainly to reduce costs, since investment in defence is restricted to situations actually requiring defence. ISR can incur allocation costs and other, indirect costs, which ultimately may lead to fitness costs. Evolution of any defensive trait depends on both what a plant ideally 'should do and what it actually 'is able to do. Costs of defence constrain its expression. This might have important influences on the evolution of plant defensive traits, as well as on the exploitation of natural defences in agricultural crop protection.     

Seroprevalence of Neospora caninum infection following an abortion outbreak in a dairy cattle herd

OBJECTIVE: To investigate the seroprevalence of Neospora caninum infection in a commercial dairy cattle herd, 15 months after detection of an abortion outbreak. PROCEDURE: Sera from the whole herd (n = 266) were examined for N caninum antibodies by indirect fluorescent antibody test (IFAT) and immunoblot analysis. Herd records were reviewed to collate serological results with abortion history, proximity to calving, and pedigree data. RESULTS: The seroprevalence of N caninum infection was 24% (63/266) for IFAT titre > or = 160, 29% (78/266) for immunoblot positive (+ve), and 31% (82/266) for IFAT > or = 160 and/or immunoblot +ve; 94% (59/63) of animals with IFAT > or = 160 were immunoblot +ve. The association between seropositivity (IFAT > or = 160 and/or immunoblot +ve) and history of abortion was highly significant (P < 0.001); the seroprevalence was 86% (18/21) in aborting cows, compared with 30% (50/164) in non-aborting animals. The abortion rate for seropositive cows was 26% (18/68) compared with 3% (3/117) for seronegative animals. IFAT titres of infected cows were higher within 2 months of calving than at other times (P < 0.001). The association between seropositivity in dams and daughters was highly significant (P = 0.009). CONCLUSIONS: The abortions were associated with N caninum infection and there was evidence of reactivation of latent infection close to calving and congenital transmission of infection. Immunodominant antigens identified by immunoblots may prove useful for improved diagnostic tests.     

抗猪传染性胃肠炎M蛋白单克隆抗体的制备及部分特性鉴定

以纯化的猪传染性胃肠炎病毒重组M蛋白免疫BALB/c小鼠,按常规方法进行融合、筛选,最终获得3株抗TGEVM蛋白的杂交瘤细胞系1B3、3C2、4A5,染色体平均记数为89对、92对、90对,间接ELISA检测1B3、3C2、4A5细胞培养上清的效价分别为1/4000、1/1000、1/4000,腹水效价分别为2×10~4、2×10~5、2×10~5。通过间接ELISA做病原检测,这3株单抗不与猪流行性腹泻病毒、猪伪狂犬病病毒和猪轮状病毒发生交叉反应,而与传染性胃肠炎病毒显示良好的特异性。用制备的单抗通过间接免疫荧光做病原检测,发现染色后TGEV感染的细胞培养物在胞浆和细胞膜上出现黄绿色荧光,未接种病毒的细胞培养物未见有黄绿色闪亮荧光,结果表明,所制备的抗重组TGEVM蛋白的单抗对病原检测具有很高的特异性,为TGEV准确快速的病原诊断和TGEV感染相关的基础性研究提供了物质基础。     

猪伪狂犬重组抗原间接ELISA诊断方法的建立

本研究应用重组抗原,成功建立了检测猪伪狂犬病病毒血清抗体的间接ELISA诊断方法。通过方阵滴定确定了抗原最适包被量为1.45μg/孔,血清最适稀释度为1∶80,其作用时间为60 min,酶标抗体最适作用时间为60 min。其阳性临界值为OD≥0.123。此外,该抗原不与猪其他疾病的阳性血清反应,具有良好的特异性;批内重复试验,变异系数小于10%。该方法与进口诊断试剂盒的符合率为96.3%。本研究为现地免疫猪群抗体检测和进行PRV流行病学调查提供了一种简便的血清学诊断方法。     

用间接免疫荧光染色法检测鸭病毒性肠炎病毒在人工感染鸭体内的侵染过程和分布规律

用鸭病毒性肠炎病毒（DEV）CHv强毒株感染成年鸭复制鸭病毒性肠炎急性病例,分别于接种后不同时间,取心、肝、脾、肺、肾、胸腺、食道、十二指肠、胰腺、法氏囊和脑组织,制作切片,应用间接免疫荧光染色法（IFA）检测DEV在鸭体内的侵染过程和分布规律。结果显示：感染后4 h可在脾脏、胸腺和法氏囊中检测到DEV抗原;感染后6 h可在肝脏、食道、十二指肠、直肠及肺脏检测到DEV抗原;IFA对各组织器官中DEV的平均检出率为肝脏46/50、脾脏48/50、肺脏46/50、肾脏0/50、肠道46/50、法氏囊46/50、胸腺47/50、胰腺0/50、大脑0/50、食道44/50、心脏0/50。研究表明：在急性病例中,脾脏、法氏囊、胸腺、食道、肠道、肝脏和肺脏为DEV的主要靶器官;接种后,病毒首先在脾脏、胸腺、法氏囊中出现,然后病毒迅速传播到肝脏、消化道和肺脏中;IFA检测石蜡切片中DEV的方法具有直观、特异性强的优点,是对DEV进行检测和抗原定位的较好方法。     

抗猪附红细胞体单克隆抗体的制备

以纯化的猪附红细胞体免疫BALB/c小鼠,运用淋巴细胞杂交瘤技术进行细胞融合,并用间接ELISA方法进行筛选,经过间接ELISA方法、免疫印迹和间接免疫荧光试验进行鉴定,共获得5株分泌抗猪附红细胞体单克隆抗体的杂交瘤细胞,分别命名为1H1、1H2、3A5、5B1和7E11,其单抗亚类鉴定分别属于IgG2b、IgG1、IgG2b、IgG2b和IgG2b。这5株McAb均能与猪附红细胞体全菌蛋白发生特异性反应,而不与猪肺炎支原体、猪链球菌、大肠杆菌和猪繁殖与呼吸综合征病毒发生反应,并且1H1、3A5和5B1能识别同一抗原位点,1H2和7E11识别另一抗原位点。     

草坪产业化

就我国草草坪产业化,提出了草坪文化、价值、产业和全面国家安全生态国防的观点,旨在转变传统观念,确立全民生态保护意识,实现产业兴国。     

罗城县雷暴天气活动规律及其灾害防御

利用广西罗城县1980—2009年的雷暴资料,通过统计分析雷暴活动的状况,年变化趋势,季节、月和日分布特征,找出了雷暴活动的时间和空间上的变化规律,分析了1980—2009年来雷暴发生影响的天气系统,计算出各天气条件下雷暴发生的概率。为今后雷电活动监测和分析提供依据,为防灾减灾工作提供参考,同时也比较具体地提出了灾害的防御措施,从而为加强罗城县雷暴防御提供参考。