苎麻花叶病的研究I．病原探讨

１９８５年用四环素、青霉素处理苎麻花叶病病株，症状并未减轻。用４％ＰＴＡ负染方法对病叶汁液进行电镜观察，在Ｃ２－１４、芦竹青、细叶绿品种中均见到线状病毒粒子．３次嫁接试验表明可使健康接穗产生相同症状，进一步证实此病由线状病毒引起．     

Lettuce chlorosis virus — A new whitefly-transmitted closterovirus

A previously undescribed viras disease of lettuce, sugarbeets, other crop and weed hosts was found in the southwest desert regions of U.S.A. Affected lettuce and sugarbeet hosts exhibited interveinal yellowing, stunting, rolling, and brittleness of affected leaves. Since 1990, yellowing symptoms on desert lettuce and sugarbeet were shown to be induced by a mixture of lettuce infectious yellows viras (LIYV) and this previously undescribed viras termed lettuce chlorosis viras (LCV). LCV is a closterovirus with flexuous, filamentous particles 800–850 nm long. The viras is transmitted efficiently by bothBemisia biotypes. LCV differs significantly from LIYV and other previously described viruses in host range (LCV does not infect the Cucurbitaceae), insect transmission, and serology.     

病毒细菌协同凝集试验在蔬菜病毒检测中的应用

在蔬菜病毒病的病毒细菌协同凝集试验（简称ＶＢＡ法）中,首次比较了金黄色葡萄球菌Ｃｏｍｎ１和Ｎｏ．１８００菌株对ＶＢＡ灵敏度的影响,结果表明用Ｎｏ．１８００菌株代替国内、外通用的Ｃｏｍｎ１菌株,ＶＢＡ检测ＴｏＭＶ、ＣＭＶ和ＰＶＸ纯病毒的灵敏度提高了２～１０倍,达３．４～１３．０ｎｇ／ｍＬ,检出病汁液的最大稀释度达１０３～１０５,其灵敏度接近于Ａ蛋白酶联法。在此基础上,又将经抗血清致敏的金黄色葡萄球菌液体免疫剂冷冻干燥,制成一种新型的固体免疫剂,可在４℃下保存;在－１０℃贮藏１年后,用ＶＢＡ法检测ＴｏＭＶ、ＣＭＶ和ＰＶＸ纯病毒的灵敏度分别为８１、２０５和２１０ｎｇ／ｍＬ;即使在１５℃下贮藏１年,灵敏度仍高达２～６μｇ／ｍＬ;在２５℃下贮藏３个月,还有一定的效价。而液体免疫剂不能在１５℃下贮藏;在４℃下贮藏１０个月即失效。因此,固体免疫剂既保持了原液体免疫剂灵敏度高、特异性强、快速简便和经济的特点,又增加了耐贮藏的优点,更加适合在基层单位推广使用。     

The Use of Molecular Beacons Combined with NASBA for the Sensitive Detection of Sugarcane Yellow Leaf Virus

Sugarcane yellow leaf virus (ScYLV) is widely distributed in Brazil and other sugarcane producing countries causing significant yield losses. Due to the high incidence of the aphid vector, the virus is widespread in the field and in parental clones used in sugarcane breeding programmes. Aiming to present a sensitive and reliable detection of ScYLV, we have adapted an AmpliDet RNA system, compared it with the currently available detection methods and discussed its applicability for routine diagnosis. AmpliDet RNA consists of nucleic acid sequence-based amplification (NASBA) of the target RNA with specific primers and simultaneous real-time detection of the amplification products with molecular beacons. The results showed that the system produced a detection level of at least 100fg of purified virus. Virus was readily detected in plant tissues with low levels of infection (without the need of previous RNA extraction) and in the hemolymph of aphids. The method showed to be virus-specific, testing negative for other species of the Luteoviridae. In conclusion, the system has potential to become a diagnostic method for the detection of sugarcane viruses.     

广西高致病性 PRRSV Nsp2基因的克隆、序列分析和抗原表位预测

根据猪繁殖与吸吸综合征病毒(PRRSV)VR2332 Nsp2基因序列合成特异性引物,对广西分离的高致病性PRRSV进行RT-PCR扩增,将扩增出的796 bp片段插入pMD18-T载体中进行序列测定和分析,并用DNA Star软件对Nsp2基因推导的氨基酸序列进行了表位分析。结果显示,广西3个县、市的PRRSV分离株Nsp2基因第483位和第532位~第560位氨基酸发生缺失,核苷酸序列之间的同源性为97.0%~97.4%,推导编码的氨基酸序列之间的同源性为93.6%~94.7%;与PRRSV VR2332株、MLV株和CH-1a株核苷酸之间的同源性分别为79.0%~79.2%、78.8%~78.9%和88.2%~89.3%;氨基酸之间的同源性分别为59.4%~60.2%、59.4%~60.2%和70.9%~81.6%,表明广西3个县、市的PRRSV分离株Nsp2基因与VR2332株、MLV株和CH-1a株比较变异较大。表位分析表明,由于博白株的Nsp2基因的第532位~560位氨基酸的缺失,与VR2332株比较,其亲水性、抗原指数均发生了大的变化。     

我国部分地区梅树病毒病的病原初步检测

梅是一种原产于中国、具有重要经济价值、花果兼用型的树种。在其生长繁育过程中易受病毒等病原侵染,从而可能造成严重的经济损失。目前我国梅树上病毒的发生及分布尚不清楚。为此,对无锡、武汉、上海、杭州、南京的梅园进行了调查,采集了115份样品,其中发现了疑似病毒病害,主要症状表现为花叶、卷叶、叶片皱缩、褪绿、脉间失绿等。RT-PCR检测出了苹果茎沟病毒(ASGV)、樱桃病毒A(CVA)和亚洲李属病毒2(APV 2),检出率分别为30.4%、4.3%和3.5%。此外,克隆了这三种病毒的外壳蛋白基因序列,同GenBank已登录的相应序列相似性为86%~99%(核苷酸水平)和83%~99%(氨基酸水平)。序列比较发现APV2梅分离物与日本梅分离物亲缘关系较近。     

LZ-8蛋白的原核密码子优化表达及免疫调节功能的初步检测

    为研究LZ-8蛋白的免疫调节活性,设计合成12个寡核苷酸片段,并用PCR方法将它们连接为经密码子优化的新LZ-8基因;将该新基因克隆至原核表达载体pET-28b,构建重组表达质粒pET-28b_lz8,并在大肠杆菌BL21中进行诱导表达.表达产物经Ni离子亲和层析法纯化后,蛋白表达量达70 mg·L-1.通过不同品系小鼠的皮肤移植模型检测表明:纯化的重组蛋白具有一定程度的免疫抑制功能,还需进一步实验验证.     

非洲猪瘟病毒生物学特性及在猪肉生产中的防控措施研究

非洲猪瘟是一种烈性外来疾病,不属于人畜共患病,但会造成大量猪死亡,自中国首次发现疫情以来,多个地区相继暴发疫情,扑杀大量生猪,给生猪养殖业带来巨大的损失。目前还没有针对非洲猪瘟的特效药和有效疫苗,还需要进一步的研究。该文从非洲猪瘟病毒的生物学特性、防控难点以及在猪肉食品生产中的防控方法等方面进行概述,提出食品企业应做好应对措施,在食品生产过程中全面防控,增强从业人员的防控意识,防止非洲猪瘟病毒通过猪肉产品在市场中传播,旨在为抑制非洲猪瘟的扩散和食品企业对非洲猪瘟病毒的防控提供参考。