Development of a disperse dye immunochromatographic test for the detection of antibodies against infectious bursal disease virus

For investigating the feasibility of using disperse dyes as an immunoassay chromogenic marker, a disperse dye, DADISPERSE NAVY BLUE SP, was selected in analyzing antibody against infectious bursal disease virus (anti-IBDV). With the color intensity revealed in the disperse dye immunochromatographic test (DICT) strip as the objective function, the optimal dyeing conditions were found as follows: dye concentration absorbance (at lambda(max)=587nm)=3, pH 7, 50 degrees C, for 10min. Under these conditions, the resultant dyed-antibody (rabbit anti-chicken) can produce an optimal color intensity reading of 55,054 on the strip. For performing qualitative immunoassay, chicken sera samples taken from different farms were used for the anti-IBDV titre assessment. The results of DICT strips showed very high sensitivity and specificity as compared to that analyzed by FlockChek enzyme linked immunosorbent assay (F-ELISA) kits. For quantitative immunoassay, it was found that the color intensity measured with DICT was linearly correlated to that of F-ELISA titre (r(2)=0.9687). Therefore, DICT was further applied to the detection of chicken anti-IBDV sera under vaccination in the farms. The average titres of the sampling groups exhibited a strong agreement to that of F-ELISA. Accordingly, the DICT method developed in this study, shown to be reliable, cheap and simple in both qualitative and quantitative immunoassays, is particularly suitable for point-of-need testing (PONT) in agricultural applications.     

三聚氰胺对小鼠睾丸病理损伤的观察

本研究采用组织病理学和免疫组织化学技术观察了三聚氰胺（Melamine,MA）对雄性小鼠睾丸的毒性作用,以深入揭示三聚氰胺的毒性作用及其机理。将25只28日龄SPF雄性昆明小鼠随机均分为5组,1组为对照组,其他4组为试验组。4个试验组分别按下述不同剂量灌服三聚氰胺：0.6 mg/kg（bw）/d（每日每公斤体重0.6 mg）、3.0 mg/kg（bw）/d、15.0 mg/kg（bw）/d和17.5 mg/kg（bw）/d,用玉米油做溶剂;空白对照组每日灌服等量玉米油。连续灌胃30天后剖检小鼠并取其睾丸组织进行固定、切片和染色,观察睾丸的组织病理变化。同时,采用免疫组织化学方法检测睾丸组织中增殖细胞核抗原（PCNA）的表达量。观察结果表明,与对照组相比,试验组不同剂量浓度的三聚氰胺对小鼠睾丸组织造成不同程度的病理损伤;三聚氰胺也会在一定程度上影响睾丸组织中PCNA的表达。研究结果表明三聚氰胺对于小鼠生殖系统有明显毒性作用。     

动物科学专业实践教学环节教学效果的调查分析与改革思路

动物科学专业是我国高等农业院校均开设的一门传统专业课。动物科学专业所具有的实践性及应用性等学科特点,决定了实践教学环节在分析探讨其整个教学系统中占有非常重要的地位。对动物科学专业实践教学环节的教学效果进行了问卷调查,分析并探讨了其改革思路。结果表明,学生对该专业的实践教学环节总体上是满意的,但在专业技术综合训练及科研训练等方面,尚需在以后的教学方案改革中进一步完善。     

Calcium homeostasis and its relationship to superoxide production in blood and milk neutrophils of lactating goats

Polymorphonuclear neutrophils (PMN), which comprise over 70% of the somatic cells in goat milk, are a major cellular component of innate immunity in the goat mammary gland. However, the function of milk PMNs is modified after diapedesis compared to PMNs in blood. As many aspects of PMN activity depend directly on intracellular Ca²⁺ concentration ((Ca²⁺)_i), the present study aimed to determine the changes in Ca²⁺ homeostasis of milk PMNs from lactating goats compared to autologous blood PMNs, and to examine the significance of these variations to the immuno-competency of milk PMNs. The intracellular Ca²⁺ store of freshly prepared milk cells was estimated from the elevation of (Ca²⁺)_i after ionomycin treatment, which was found to be significantly less than blood PMNs. Replenishment of the intracellular Ca²⁺ store in milk cells after intracellular Ca²⁺ depletion by Bapta-AM followed by spiking with 2.5 mM Ca²⁺ for 20 min was also compared to that of blood PMNs, showing that after depletion/spiking the intracellular Ca²⁺ store in milk cells was much less than blood PMNs. The production of superoxide anion (O₂^?) in vitro in response to (Ca²⁺)_i-dependent or (Ca²⁺)_i-independent modulators was used to evaluate the relevance of altered Ca²⁺ homeostasis on the immuno-competency of milk cells compared to blood PMNs. The results indicated that milk cells produced similarly low levels of O₂^? as blood PMNs when treated with ionomycin. However, the amount of O₂^? produced by milk cells in response to phorbol 12-myristate 13-acetate (PMA) stimulation, although greater than ionomycin treatment, was significantly less than that of blood PMNs. The capacity for O₂^? production by both cell types in response to PMA reverted to the resting state with use of the protein kinase C (PKC) inhibitor, staurosporine. In conclusion, the current study demonstrated an irreversible shortage of intracellular Ca²⁺ in the milk PMNs of lactating goats compared to blood PMNs. It also showed that preliminary O₂^–production, primed by ionomycin treatment, remained unchanged in milk PMNs, despite the shortage in intracellular Ca²⁺, but decreased O₂^? production capacity, mediated via the PKC pathway, in milk PMN. It is suggested that the defects in Ca²⁺ homeostasis in milk PMNs of lactating goats is partially attributable for the post-diapedesis functionality modifications.     

盐胁迫对星星草幼苗保护酶系统的影响

在盐胁迫下,星星草幼苗过氧化氢酶活性随着胁迫时间的延长而增强,并与盐浓度呈显著正相关。超氧化物歧化酶活性随着胁迫浓度的增强而增强,当超过一定浓度(3.0%Na₂CO₃)时则趋减弱,尔后随着胁迫时间的延长而增强。过氧化物酶活性的变化规律与超氧化物歧化酶活性相似,但变化幅度较小。丙二醛含量随着胁迫时间的延长和胁迫强度的增强而增加。     

临界氮浓度稀释模型在牧草种子生产中的应用前景

氮素是影响牧草种子产量的关键因素,氮素对于植株分蘖、干物质生产、花序形成、产量组分动态变化等均具有影响.文章主要从临界氮浓度稀释模型的概念、构建方法、研究现状、应用等方面进行了综述,提出临界氮浓度稀释模型在实际生产中应用时存在的问题,并对其在牧草种子生产中的应用前景进行了展望.     

Characterization of antibody response to porcine reproductive and respiratory syndrome virus ORF5 product following infection and evaluation of its diagnostic use in pigs.

The sensitivity and specificity of recombinant open reading frame 5 products used in the Western blotting assay for confirmation of porcine reproductive and respiratory syndrome virus (PRRSV) serologic status were evaluated. The recombinant antigen-based assays were specifically compared with a commercial enzyme-linked immunosorbent assay (ELISA) for PRRSV antibodies using 1) PRRSV antibody-negative reference sera (n = 30), 2) naturally infected pig sera (n = 40), 3) sequential sera obtained from 24 experimentally infected pigs, and 4) sera submitted to 3 state diagnostic laboratories (n = 200). The recombinant antigen assay yielded an average increased sensitivity of 10% over the commercial PRRSV ELISA. The negative controls (group 1 sera) showed no difference between the 2 assays. This comparison confirmed that the recombinant antigen-specific assay was more sensitive than the commercial ELISA and is well suited for routine confirmation of the presence of PRRSV antibodies.     

我国牧草种质资源保存、利用与保护

牧草是自然资源的重要组成部分,也是农业可持续发展的物质基础,在我国草地畜牧业生产、生态环境及人民生活中发挥着巨大的作用。为此,论述了我国牧草种质资源调查、收集、保存、研究和利用的现状,存在问题及对今后发展的建议,提出今后应加强优良和珍稀牧草种质的搜集、生态型及遗传多样性的研究和利用、生物技术在优良牧草种质创新的应用、种质保存的时效性和野生状态下牧草遗传变异与进化的速率、短寿命牧草种子保存技术、优良基因的发掘和功能研究以及利用平台的构建、物种或种群保护的生物学基础研究7个重点领域的研究。     

Characterization of porcine circovirus type 2 (PCV2) infection in swine lymphocytes using mitogen-stimulated peripheral blood lymphocytes from healthy PCV2-carrier pigs

Information regarding the susceptibility of swine lymphocytes to PCV2 is rather limited. To further explore and characterize the PCV2 infection in swine lymphocytes, an in vitro model using concanavalin A (Con A)-stimulated peripheral blood lymphocytes (PBLs) obtained from clinically healthy PCV2-carrier pigs was introduced. It was found that the PCV2 antigen-containing rate was below 2% in PBLs from healthy PCV2-free pigs following treated simultaneously with Con A and PCV2. However, significantly higher PCV2 antigen- and nucleic acid-containing rates could be seen in Con A-stimulated PBLs from clinically healthy PCV2-carrier pigs. Prior to Con A treatment, both of the PCV2 antigen- and nucleic acid-containing rates in PBLs from healthy PCV2-carrier pigs were less than 1%; however, they reached 22.1+/-5.7% by flow cytometry and 27.1+/-6.5% by in situ hybridization, respectively, at 4-day post-incubation with Con A. Phenotyping of PCV2 antigen-containing cells revealed that PCV2-positive cells could be detected in both T and B lymphocyte populations within which IgM-positive B lymphocytes appeared to have a relatively higher positive rate. The Con A-stimulated PBLs also displayed a significantly higher viral load by the measurement of either PCV2 DNA copy number or viral titer when compared with the non-treated PBLs from healthy PCV2-carrier pigs. The results indicate that PBLs, especially IgM-bearing B lymphocytes, are indeed susceptible to PCV2 infection and PCV2 is capable of replicating in dividing lymphocytes. This activation-induced replication may explain in part the pathogenesis of lymphoid depletion in PMWS-affected pigs.     

乳猪体内糖类的消化和吸收研究

乳猪小肠内葡萄糖的分布状况既与饲料的碳水化合物种类和数量相关，也与小肠的不同部位相关，十二指肠段和空肠段分别是乳糖、淀粉类碳水化合物分解和葡萄糖吸收的主要部位血糖浓度离肝脏越远含量越低，而与饲料中糖类含量的多少无关。