玉米褪绿斑驳病毒及传播介体研究进展

玉米褪绿斑驳病毒(Maize chlorotic mottle virus,MCMV)是中国重要检疫性病毒之一,该病毒与马铃薯Y病毒属成员复合侵染会造成玉米致死性坏死（CLN）,造成严重的经济损失。由于玉米上马铃薯Y病毒属病毒有广泛适生范围,一旦扩散开来,将对玉米生产构成严重威胁。因此,了解MCMV研究的现状和传播介体具有重要意义。综述了近几年MCMV研究进展和传播介体概况,并结合自身研究,评述了西花蓟马作为MCMV传播介体在CLN中的作用,以期为西花蓟马传播MCMV的基础研究和防控提供理论依据。     

CD20片段抗体在红花悬浮细胞中的表达研究

【目的】研究用红花愈伤组织建立红花悬浮细胞培养体系的条件,并利用红花悬浮细胞通过农杆菌介导转化法表达CD20复合片段抗体。【方法】以红花子叶为外植体,研究不同种类激素组合对愈伤诱导率的影响,筛选优质愈伤组织进行悬浮培养,探索不同初始接种量、蔗糖质量分数、水解酪蛋白质量浓度对红花悬浮细胞生长的影响。将CD20复合片段抗体基因两端引入XmaⅠ/EcoRⅠ酶切位点,并将其与pEASY-T1和pBasta载体相连,构建pEASY-T1-CD20克隆载体和pBasta-CD20表达载体,再将构建的pBasta-CD20表达载体转入根瘤农杆菌,利用根瘤农杆菌介导红花悬浮细胞转化法表达CD20复合片段抗体。【结果】红花子叶愈伤诱导最佳条件为MS+NAA 2mg/L+6-BA 0.5mg/L、温度(25±0.1)℃、光照70μmol/(m2·s)连续光照,继代培养条件为MS+NAA 1mg/L+6-BA 0.5mg/L、30μmol/(m2·s)连续光照、温度(25±0.1)℃。悬浮细胞体系培养最佳条件为不加琼脂粉的MS+NAA 1mg/L+6-BA 0.5mg/L、接种量2.5g(50mL培养基)、蔗糖质量分数2%、水解酪蛋白800mg/L。pBastaCD20表达载体构建成功,且目的蛋白在红花悬浮细胞中成功表达。【结论】成功构建了红花悬浮细胞培养体系,并用该体系成功表达了CD20复合片段抗体。     

Insecticide resistance and,efficacy of space spraying and larviciding in the control of dengue vectors Aedes aegypti and Aedes albopictus in Sri Lanka

Unprecedented incidence of dengue has been recorded in Sri Lanka in recent times. Source reduction and use of insecticides in space spraying/fogging and larviciding, are the primary means of controlling the vector mosquitoes Aedes aegypti and Ae. albopictus in the island nation. A study was carried out to understand insecticide cross-resistance spectra and mechanisms of insecticide resistance of both these vectors from six administrative districts, i.e. Kandy, Kurunegala, Puttalam, Gampaha, Ratnapura and Jaffna, of Sri Lanka. Efficacy of the recommended dosages of frequently used insecticides in space spraying and larviciding in dengue vector control programmes was also tested.     

Bartonella species and their ectoparasites: selective host adaptation or strain selection between the vector and the mammalian host?

A wide range of blood-sucking arthropods have either been confirmed or are suspected as important vectors in Bartonella transmission to mammals, including humans. Overall, it appears that the diversity of Bartonella species DNA identified in ectoparasites is much broader than the species detected in their mammalian hosts, suggesting a mechanism of adaptation of Bartonella species to their host-vector ecosystem. However, these mechanisms leading to the fitness between the vectors and their hosts still need to be investigated.     

Strategies for bacterial tagging and gene expression in plant-host colonization studies

Bacteria are extraordinarily diverse microorganisms with a huge potential to benefit environmental and agricultural systems. Comprehensive studies in complex habitats such as soils and plants have led to the development of genetic tools to evaluate gene expression and bacterial colonization under controlled or environmental conditions and to obtain genetically engineered organisms for environmental release. In addition, current advances in genomic and metagenomic research will add to the number of genes with potential for biotechnological applications, which will require the development of appropriate genetic systems to fulfill their potential for both industrial and agricultural applications. The aim of the present review is to assess the approaches and recent progress in vector design and genetic tools to study and manipulate plant-bacterial interactions, as well as strategies to construct genetically modified strains for environmental release.     

Non-traditional vectors for paralytic shellfish poisoning

Paralytic shellfish poisoning (PSP), due to saxitoxin and related compounds, typically results from the consumption of filter-feeding molluscan shellfish that concentrate toxins from marine dinoflagellates. In addition to these microalgal sources, saxitoxin and related compounds, referred to in this review as STXs, are also produced in freshwater cyanobacteria and have been associated with calcareous red macroalgae. STXs are transferred and bioaccumulate throughout aquatic food webs, and can be vectored to terrestrial biota, including humans. Fisheries closures and human intoxications due to STXs have been documented in several non-traditional (i.e. non-filter-feeding) vectors. These include, but are not limited to, marine gastropods, both carnivorous and grazing, crustacea, and fish that acquire STXs through toxin transfer. Often due to spatial, temporal, or a species disconnection from the primary source of STXs (bloom forming dinoflagellates), monitoring and management of such non-traditional PSP vectors has been challenging. A brief literature review is provided for filter feeding (traditional) and non-filter feeding (non-traditional) vectors of STXs with specific reference to human effects. We include several case studies pertaining to management actions to prevent PSP, as well as food poisoning incidents from STX(s) accumulation in non-traditional PSP vectors.     

人乳铁蛋白腺病毒载体的构建及细胞表达

将人乳铁蛋白基因与腺病毒基因组骨架质粒重组,在293细胞中包装重组腺病毒颗粒,获得真核细胞表达的栽体pAd-hLTF.以pcDNA3X为模板,PCR扩增hLTF基因,腺病毒穿梭栽体pshuttle-cmv与hLTF重组为pshuttle-cmv-hLTF:再与腺病毒骨架质粒pAdEasy-1同源重组为pAd-hLTF质粒:脂质体法将重组pAd-hLTF质粒转染HEK 293细胞.包装成重组腺病毒颗粒.Western blot和ELISA法测定细胞中hLTF基因的表达.结果表明,pAd-hLTT质粒转染293细胞后,7～10 d后,获得细胞裂解液,将细胞裂解产物再次接种新鲜的293细胞,3～5 d后,80%以上的细胞变圆、膨胀、漂浮.Westem blot和ELISA结果显示,上清液中有hLTF基因的表达,为重组人乳铁蛋白的体外表达及其功能分析奠定了基础.     

Occurrence, Distribution and Epidemiology of Grapevine Yellows in Spain

The main viticultural production areas in Spain were surveyed in 1994, 1995 and 1996 for the occurrence and incidence of Grapevine Yellows diseases associated to phytoplasmas. Samples from 300 plants showing symptoms of phytoplasma infection were collected from grapevine fields in the Spanish regions of Aragón, Catalonia and Navarra and analysed by PCR with specific primers for a non-ribosomal DNA of stolbur/Bois Noir (BN) and of Flavescence dorée (FD) phytoplasma. Nested PCR with universal primers P1/P7 and fU5/rU3 was also used. In the survey conducted in 1994 and 1995 only BN/stolbur phytoplasma was detected. The incidence of symptomatic plants was low in five plots of Catalonia from 3% to 18% in 1994 and 1995, respectively, and high in two plots of Navarra, from 60% to 80%. In the survey conducted in 1996 the incidence of symptomatic plants in Catalonia increased (6–80%) due to the presence of FD in five plots in the Northeastern Catalonia. An epidemiological study was carried out in two BN-affected plots of two regions from 1994 to 1997, with the evaluation of potential vectors and of host plants. The stolbur phytoplasma was found in individuals from different insect species belonging to the families Cicadellidae and Delphacidae. Some wild plants naturally infected with stolbur phytoplasma around the infected grapevines were: Convolvulus arvensis, Lavandula officinalis, Polygonum convolvulus, Solanum nigrum, and Thymus officinalis. The incidence of the disease in one BN-infected grapevine plot increased from 3.4% in 1994 to 18.40% in 1997.     

小反刍兽疫病毒H、F基因转基因苜蓿表达载体的构建

为了有效预防小反刍兽疫,试验以pBI121为载体,PPRV-H、PPRV-F为目的基因,并插入绿色荧光蛋白(GFP)基因、MAR序列,构建5种小反刍兽疫病毒(PPRV)苜蓿表达载体。结果表明:成功构建小反刍兽疫表达载体,再将表达载体转入苜蓿,饲喂动物,选择其中免疫效果最好的表达载体,为该病的预防工作提供有效的技术支持。     

麦二叉蚜传播玉米矮花叶病毒的机制

用胶体金标记法和荧光抗体标记法研究了麦二叉蚜(Schizaphis graminum)传播玉米矮花叶病毒(Maize dwaft mosaic virus,MDMV)的机制。麦二叉蚜传播玉米矮花叶病毒需要辅助成份-蛋白酶(Helper component-proteinase,HC-Pro)的参与。在电镜下观察到HC-Pro可以与MDMV粒子结合。用FITC标记的HC-Pro抗体和MDMV抗体证明,HC-Pro可以直接结合到蚜虫口针上;而MDMV粒子不能直接结合到蚜虫口针,必须在HC-Pro的辅助下才能结合到蚜虫口针上。这为HC-Pro在蚜虫传毒过程中起桥梁作用提供了新的证据。MDMV粒子主要吸附在蚜虫口针的尖端和中间部分。