New gastropod vectors and tetrodotoxin potential expansion in temperate waters of the Atlantic Ocean

Tetrodotoxin is a potent low weight marine toxin found in warm waters, especially of the Indian and Pacific Oceans. Intoxications are usually linked to the consumption of the puffer fish, although TTX was already detected in several different edible taxa. Benthic organisms such as mollusks and echinoderms, with different feeding habits, were collected monthly along the Portuguese coast from the summer of 2009 until the end of 2010. The extraction and analysis techniques were optimized and TTX and some analogues were detected for the first time in two intertidal gastropod species-Gibbula umbilicalis and Monodonta lineata by LC-MS/MS and UPLC-MS/MS. Although the levels are low, these findings suggest that monitoring of TTX and analogues in North Atlantic species should be implemented so as to detect potentially new toxin vectors and seasonal and/or geographical patterns.     

Spatiotemporal dynamics of Citrus tristeza virus in Cuba

The spatiotemporal dissemination of Citrus tristeza virus (CTV) was evaluated by DASI-ELISA in orange and grapefruit fields of six citrus producing regions in Cuba, and aphid populations were evaluated in two selected areas. The aphid species found in these areas were Toxoptera citricida (the most efficient vector of CTV), T. aurantii and Aphis spiraecola . A logistic model was the most appropriate to explain the temporal increase in the proportion of CTV-infected plants for almost all the fields. Although nearly all areas showed an increase in this proportion, there were regions of low CTV spread, which was slower in grapefruit than in orange fields. 2DCORR analysis indicated spatial dependence among immediately adjacent trees, higher in the within-row direction than in the across-row direction. Aggregation was also detected by dispersion index and binary power law fitting within quadrats of all sizes. For most fields, autocorrelation analysis showed a significant edge effect and spatial dependence among infected plants of different sub-areas. Based on these results a new tristeza management strategy was proposed for each region of the country.     

Fifty years of plant virus research at the agricultural research organization in Israel — A personal perspective

A transition from dry farming to irrigated crops occurred in the mid 1950s in Israeli agriculture. This was due to the development of major irrigation schemes and the establishment of numerous small-holder farms, but was accompanied by outbreaks of virus diseases in vegetable and ornamental crops. These viral epidemics led to an intensification of the research efforts in plant virology. The major research fields and achievements are described and prospects for the future are outlined. http://www.phytoparasitica.org posting Aug. 28, 2005.     

Development of a specific assay using RISA for detection of the bacterial agent of 'basses richesses' syndrome of sugar beet and confirmation of a Pentastiridius sp. (Fulgoromopha, Cixiidae) as the economic vector

A technique for the specific diagnosis in insects of SBRp (the γ-3 proteobacterium associated with the syndrome 'basses richesses' (SBR) of sugar beet crops in eastern France), using the RISA (rDNA intergenic spacer analysis) technique, was developed. PCR using the Alb1/Oliv1 primer pair specifically amplified a 16S-ITS region of SBRp and produced a characteristic DNA fingerprint. This PCR assay did not detect other closely related organisms, including the Arsenophonus endosymbiont of Diaphorina citri , the secondary endosymbiont of Glycaspis brimblecombei , or ' Candidatus Phlomobacter fragariae', a related phytopathogenic γ-3 proteobacterium. Six different ribosomal operons, differing in their ITS region or partial 16S sequence, were identified in SBRp. PCR amplification with Alb1/Oliv1 of DNA samples from Hemiptera species (suborders Fulgoromorpha and Cicadomorpha) collected in sugar beet fields confirmed Pentastiridius sp. as the economic vector of SBR disease. The high percentage of field- Pentastiridius sp. specimens which tested positive for SBRp reflected the importance of SBR disease in sugar beet crops. This is the first time that the RISA technique has been used as a diagnostic test for a plant pathogenic bacterium in insects.     

Virus transmission by host-specific strains ofOlpidium bornovanus andOlpidium brassicae

Zoospores of 12 isolatesO. bornovanus from geographically diverse sites and representing the three host specific cucurbit strains were tested as vectors for seven viruses using watermelon bait plants and the in vitro acquisition method. All isolates of the cucumber, melon, and squash strains transmitted melon necrotic spot carmovirus (MNSV) and cucumber necrosis tombusvirus (CNV) but none transmitted petunia asteroid mosaic tombusvirus (PAMV) or tobacco necrosis necrovirus (TNV). The isolates varied as vectors of three other carmoviruses: cucumber leaf spot virus (CLSV); cucumber soil borne virus (CSBV); and squash necrosis virus (SqNV). All cucumber isolates transmitted CLSV and SqNV but not CSBV. Some of the melon isolates transmitted CLSV and SqNV but none transmitted CSBV. Two squash isolates transmitted CSBV and SqNV but not CLSV. Two isolates ofO. brassicae transmitted only TNV and a third did not transmit any of the viruses. The species of bait plant sometimes affected transmission. The most efficient vector strains ofO. bornovanus, as determined by reducing zoospores and virus in the inoculum, were the cucumber strain for CLSV; the cucumber strain for CNV if cucumber was the bait plant or melon strain if watermelon was the bait plant; and the squash strain for SqNV. The plurivorous strain ofO. brassicae was the most efficient vector of TNV.Olpidium bornovanus is the first vector reported for CSBV and is confirmed as a vector of SqNV. It is proposed that all carmoviruses may have fungal vectors.Ligniera sp. did not transmit any of the viruses in one attempt.Abbreviations CLSV cucumber leaf spot virus - CNV cucumber necrosis virus - CSBV cucumber soil borne virus - MNSV melon necrotic spot virus - PAMV petunia asteroid mosaic virus - SqNV squash necrosis virus - TNV tobacco necrosis virus - TBSV tomato bushy stunt virus     

RT-PCR克隆广谱抗病基因NPR1及其蛋白表达载体构建

[目的]克隆植物广谱抗病基因NPR1并构建其蛋白表达载体。[方法]提取拟南芥总RNA,设计相关引物,采用反转录PCR方法克隆NPR1基因;利用酶切连接方法,将该基因正向导入蛋白表达载体。[结果]经过相关检验,将NPR1正向插入pMXB10载体中,得到了pMXB10-NPR1蛋白表达载体。[结论]成功构建了包含NPR1的蛋白表达载体。     

中菲水稻病毒病的比较研究Ⅴ．水稻种质对病毒及其介体的抗性

采用网箱集团接种结合玻管定苗定虫接种技术，测定比较了中菲栽培稻的８１个品种和野生稻的３个种，对两国水稻东格鲁病和水稻草状矮化病的病原病毒及其介体的抗性，筛选出了能同时抗水稻东格鲁球状病毒（ＲＴＳＶ）、水稻东格鲁杆状病毒（ＲＴＢＶ）和水稻草状矮化状病毒（ＲＧＳＶ）的３个株系以上的多抗性抗源─中山红无名种、Ｏｒｙｚａｎｉｖａｒａ和Ｏ．ｏｆｆｉｃｉｎａｌｉｓ，高抗这些病毒两个株系以上的多抗性品种─汕优桂３３、金早６号、ＨＢ４３７、Ｐａｎｋｈａｒｉ２０３、ＩＲ２８、ＩＲ５８和赤块矮选．高抗ＲＴＳＶ、ＲＴＢＶ介体黑尾叶蝉的品种─ＩＲ２８、ＧａｍＰａｉ３０１２－１５和Ｐａｎｋｈａｒｉ２０３，高抗ＲＧＳＶ介体褐飞虱的品种─ＩＲ２８和ＩＲ６４．     

Potential vector species of carp edema virus (CEV)

During a PCR‐based CEV survey in Poland in 2015–2017, the virus was detected in many farms both in clinical and asymptomatic cases and in common as well as in koi carp (Cyprinus carpio). In order to evaluate the potential carrier role of fish species that share the same habitats with carp, an experimental trial was performed. Investigations carried out on specimens of bleak (Alburnus alburnus), crucian carp (Carassius carassius), European perch (Perca fluviatilis), Prussian carp (Carassius gibelio), roach (Rutilus rutilus) and tench (Tinca tinca) cohabited with CEV‐infected carp yielded positive results. These species of fish were experimentally cohabited with CEV‐infected common carp at a temperature of 16°C ± 1. Material from the brain, gills, spleen, kidneys, intestine and skin was investigated for the presence of CEV DNA. Similar investigations were performed with uninfected fish designated controls. Samples were tested for CEV by qPCR.     

牛病毒性腹泻病毒E0基因重组表达质粒pMG36e-E0的构建与免疫原性分析

利用SacⅠ、HindⅢ限制性内切酶分别对pMG36e与pMD19-T-E0进行双酶切,将目的基因E0整合入穿梭表达载体pMG36e,构建牛病毒性腹泻病毒E0基因重组表达质粒pMG36e-E0。提取重组质粒pMG36e-E0,进行双酶切鉴定及PCR鉴定。将阳性重组质粒pMG36e-E0转化到大肠杆菌DH5α中进行表达,对表达产物进行SDSPAGE和Western-blotting鉴定。用表达的E0蛋白二次免疫家兔,间接ELISA法检测其血清抗体水平。结果,重组质粒经双酶切得到大小分别约为3 600、691bp的2个片段,PCR扩增出691bp的片段,双酶切与PCR鉴定结果表明目的基因E0正确插入到载体pMG36e中。SDS-PAGE电泳结果表明E0基因在大肠杆菌获得了表达,表达产物相对分子质量大小约为27 000。Western-blotting分析结果证明表达产物能被BVDV阳性血清所识别。ELISA检测结果证明表达的E0融合蛋白能刺激动物产生抗体,具有天然蛋白的免疫原性。     

Current Status and Perspective on the Use of Viral-Based Vectors in Eukaryotic Microalgae

During the last two decades, microalgae have attracted increasing interest, both commercially and scientifically. Commercial potential involves utilizing valuable natural compounds, including carotenoids, polysaccharides, and polyunsaturated fatty acids, which are widely applicable in food, biofuel, and pharmaceutical industries. Conversely, scientific potential focuses on bioreactors for producing recombinant proteins and developing viable technologies to significantly increase the yield and harvest periods. Here, viral-based vectors and transient expression strategies have significantly contributed to improving plant biotechnology. We present an updated outlook covering microalgal biotechnology for pharmaceutical application, transformation techniques for generating recombinant proteins, and genetic engineering tactics for viral-based vector construction. Challenges in industrial application are also discussed.