烟草花叶病毒六个分离物生物学性状初步研究

 测定了番茄条斑分离物(TMV-L₁)、番茄花叶分离物(TMV-L₂)、小青菜花叶分离物(TMV-B₁)、大白菜灰心病分离物(TMV-B₂)、地黄病毒病分离物(TMV-R)和烟草花叶分离物(TMV-N)在22科82种植物上的反应。六个分离物在心叶烟、曼陀萝等7种植物的接种叶上出现局部枯斑、在番茄,龙葵等9种植物上出现系统花叶,在White Barley烟,青箱等10种植物上反应的症状不同,在测试的十字花科植物、菊科等22种植物上六个分离物的侵染力不一致,部分分离物能够侵染,部分分离物不能侵染。对百合科、大麻科等11个科中的测试植物都没有侵染力。六分分离物中只有TMV-B₁和TMV-B₂寄主范围基本一致,仅症状轻重不同。     

Fluazifop-butyl causes membrane peroxidation in the herbicide-susceptible broad leaf weed bristly starbur (Acanthospermum hispidum)

In order to clarify the action mechanism of fluazifop-butyl, an aryloxyphenoxypropionate (AOPP) herbicide in bristly starbur (Acanthospermum hispidum DC.), a unique fluazifop-butyl-susceptible broad-leaved weed, ethylene evolution and membrane lipid peroxidation in the plant seedlings were investigated. Foliar application of fluazifop-P-butyl induced ethylene evolution only from bristly starbur, but not from oat (Avena sativa L.), another fluazifop-butyl-susceptible species, and two tolerant species, pea (Pisum sativum L.) and hairy beggarticks (Bidens pilosa L.). The other AOPP herbicides, quizalofop-ethyl and fenoxaprop-ethyl, and a cyclohexanedione (CHD) herbicide, sethoxydim, did not enhance ethylene production from bristly starbur. This fluazifop-butyl-induced ethylene production in bristly starbur was completely suppressed by aminoethoxyvinylglycine (AVG), a 1-aminocyclopropane-1-carboxylic acid (ACC) synthase inhibitor, but not by p-chlorophenoxyisobutyric acid (PCIB), an anti-auxin compound, suggesting this evolved ethylene was not auxin-induced. Phytotoxic action by fluazifop-P-butyl (5 μM) in bristly starbur was reduced markedly by two lipid-soluble antioxidants, vitamin E, and ethoxyquin. The ethylene production from the plant was also inhibited by these two antioxidants. Content of malondialdehyde, an indicator of lipid peroxidation, increased only by fluazifop-P-butyl in bristly starbur seedlings but not in oat, and this increase was inhibited by ethoxyquin. These results strongly suggest that the primary site of action for fluazifop-butyl in bristly starbur is on the membranes and active oxygen species and/or free radicals are involved in peroxidation. Ethylene evolution is probably induced by these reactive oxygen species.     

Risk Analysis for Latent Infection of Prune by Monilinia fructicola in California

ABSTRACT The quantitative relationships between incidence of latent infection (ILI) of prune by Monilinia fructicola and wetness duration (WD) for different bloom and fruit developmental stages and different inoculum concentrations were obtained. Three levels of ILI were considered as criteria for low, moderate, and high risks of latent infection, respectively. Seasonal patterns of WD leading to different risk levels of latent infection were obtained for low (IP(L)) and high (IP(H)) inoculum potential conditions in orchards. Longer WD was needed at a resistant than at a susceptible fruit developmental stage to induce similar levels of latent infection. The curves of WD leading to different levels of ILI over the growing season (risky WD curves) were used in risk analysis for latent infection. Multi-year historical WD data from 10 prune-growing locations in California were compared with risky WD curves. The percentage of days (P) with WD leading to a certain risk level of latent infection was calculated for each month from historical weather data. Under the IP(L) condition, the P distributions for low risk of latent infection were higher in March and April than in May and were the lowest in June for most locations. Under the IP(H) condition, the number of days that WD leading to low risk of latent infection in May increased compared with those under the IP(L) condition. The risk analysis approach was evaluated by using separate experimental data as incidence of fruit brown rot obtained from different prune orchards over years. Consistency between predicted overall risk levels of latent infection and observed incidence of fruit brown rot was obtained. The results demonstrated the usefulness of the risk analysis in decision support system for disease management.     

Development of a loop-mediated isothermal amplification assay for rapid, sensitive and specific detection of a Campylobacter jejuni clone

Loop-mediated isothermal amplification (LAMP) assay is a simple, rapid and specific detection method and has been used for detection and identification of different Campylobacter species. In this study, we develop a LAMP assay specific for detection of a particular clone (clone SA) of Campylobacter jejuni, associated with the vast majority of recent sheep abortions in the U.S. Using a set of specific primers for C. jejuni IA3902 (a clone SA isolate) and genomic DNA or boiled cell extract as template, the target DNA was amplified at 63 °C for 50 min in a water bath. A positive reaction was identified visually as white precipitate or fluorescence under UV, and confirmed by gel electrophoresis. Detection limit of the assay was comparable to that of conventional PCR. The LAMP was shown to be specific for detection of clone SA when tested on a number of C. jejuni strains of different genetic backgrounds. Applicability of the LAMP assay for specific detection of clone SA was demonstrated in animal tissues experimentally infected with IA3902 or genetically diverse C. jejuni strains. Since clone SA is the predominant cause of sheep abortions in the U.S. and is a zoonotic pathogen, the LAMP assay may be a valuable detection tool in future epidemiological studies.     

农三师猪弓形虫病血清学调查与分析

弓形虫病是龚第弓形虫引起的一种人和多种动物共患寄生虫病。本实验通过酶联免疫吸附(ELISA)试验对采自农三师辖区8个团场的不同养殖规模猪场的900份猪血清进行弓形虫病的抗体检测,结果表明猪弓形虫病在我师呈散发性流行。样品阳性率平均为36.33%,各辖区之间的抗体阳性率有一定差异,最高为49.16%,最低为21.33%。初步掌握我师猪弓形虫病的感染状况,为基层的防治工作提供技术指导。     

岗梅根醇提液对小鼠的半数致死量(LD_(50))的测定

用寇氏(k-rber)法测定了岗梅根醇提液腹腔注射对小鼠的半数致死量(LD5)0,结果显示,岗梅根醇提液腹腔注射的LD50为37 786.27 mg/kg,95%可信限为33 744.27～42 315.55 mg/kg。表明岗梅根醇提液属实际无毒级,临床日用量安全。     

有色金属压铸成型工艺的模糊智能设计

介绍了专家系统产生式规则与模糊集合相结合的方法，阐述了压铸工艺经验表达的自然语言理解方式。此外，还开发了用以形成模糊专家系统框架核心的推理机制，并通过线性模糊矩阵代数运算予以实现。研究了有色金属压铸成型工艺模糊智能化设计中浇注温度和出模斜度的问题。结果表明，智能设计方法能够有效地表达和组织压铸工艺专家知识。     

上海外高桥口岸从进境羊毛中截获的杂草种类

上海外高桥口岸是原毛进境的重要口岸,外高桥检验检疫局在进境羊毛检验检疫中发现进境羊毛携带有大量杂草籽。本文对外高桥局2011年1～9月份进境羊毛中截获的杂草进行了统计与分析,共截获杂草10112批次,73种;其中检疫性杂草4种,435批次。并针对外来入侵杂草管理提出对策和建议。     

半巢式RT-Realtime PCR检测马铃薯Y病毒脉坏死株系

马铃薯Y病毒脉坏死株系(Potato virus Y,PVYn)是马铃薯中一个非常重要的病毒病害.本文根据PVYn基因组中RNA依赖的RNA聚合酶基因序列保守区域,设计合成了3条巢式PCR引物和1条TaqMAN荧光探针,建立了半巢式RT-Realtime PCR检测PVYn的新方法.该方法采用E.Z.N.ATM陕速提取植物总RNA,并有机地结合了巢式PCR和TaqMAN探针检测技术.第二步半巢式RT-Realtime PCR既是对第一步信号的进一步放大,也是对第一步PCR产物的确认,因此,检测的准确性、灵敏度比巢式PCR、Real time PCR等方法高.实验结果表明,该方法检测灵敏度可达4fg/μL植物总RNA.