Detection,distribution and control of Potato mop-top virus,a soil-borne virus,in northern Europe

Potato mop-top virus (PMTV; genus Pomovirus; family Virgaviridae) is transmitted by the soil-borne Spongospora subterranea f.sp. subterranea, a protoctist that causes powdery scab on potato. PMTV is distributed widely in the potato growing areas in South and North America, Japan and northwestern Europe. This article reviews the current knowledge on detection, distribution and control of PMTV with focus on the Baltic Sea region. Since the 1980s, PMTV has caused great economic losses to potato production in the Nordic countries (Norway, Sweden, Denmark and Finland), but its occurrence in other countries of the Baltic Sea region remained unknown. To fill this knowledge gap, harmonised sampling and virus detection procedures including bioassays and serological and molecular methods were employed by 21 research institutions to detect PMTV in potato tubers and soil samples in 2005–2008. Potato growing areas were widely contaminated with PMTV in the Nordic countries. Only the main seed potato production area in northern Sweden and the High Grade seed potato production zone in Finland were negative for PMTV. Intensive and systematic surveys in Poland in 2004–2008 found no evidence of PMTV, except a single PMTV-infected tuber detected in 2008. Surveys in the Baltic countries (Lithuania, Latvia and Estonia) and northwestern Russia (Leningrad province) were negative for PMTV, except infection of minitubers in a screenhouse in Latvia in 2005. Varying percentages of tubers expressing spraing symptoms in Sweden, Norway, Denmark and Poland were infected with Tobacco rattle virus, and bioassays indicated similar results for Russia. Incidence of symptomless infections with PMTV was high in tubers of many potato cultivars. Here, we discuss the contrasting patterns of distribution of PMTV in the Baltic Sea region, factors playing a role in dispersal and establishment of PMTV in new fields and means for controlling PMTV and its spread to new areas. We emphasise the use of the current virus-specific methods for the detection of PMTV in symptomless potato tubers and the high risks of disseminating PMTV to new fields and areas in viruliferous resting spores of S. subterranea in the soil adhering to seed tubers. PMTV-resistant potato cultivars will provide the only sustainable means for preventing yield losses in the infested fields and the prospects of resistance breeding are summarised.     

Comparative aspects of infectious salmon anemia virus,an orthomyxovirus of fish,to influenza viruses

Infectious salmon anaemia (ISA) is a viral disease that was first recorded in 1984 in farmed Atlantic salmon. The infectious salmon anaemia virus (ISAV) is classified as the type species of the genus Isavirus in the Orthomyxoviridae family and is evolutionary remote to the influenza viruses. The genome consists of eight negative single-stranded RNA segments, and it utilises the same mechanisms as influenza viruses to enter and exit cells. Although a common ancestor of ISAV and other genera of Orthomyxoviruses could be dated back several millions of years, there are still many similarities between ISAV and the influenza viruses regarding morphology, replication cycles and interactions with their respective hosts.     

2018-2019年云南省部分地区鼠类携带汉坦病毒基因型别分析

为了解云南省汉坦病毒的分子流行病学特征,本研究在云南省祥云县、泸西县、禄丰县和楚雄市4个地区布点,采集鼠类动物标本,运用实时荧光RT-PCR检测鼠肺标本中的汉坦病毒中的汉滩病毒和首尔病毒核酸,通过PCR扩增S节段的全基因序列,并进行核苷酸同源性分析和遗传进化分析。结果共捕获鼠类动物70份,包含10个鼠种,其中褐家鼠30只,占42.9%,其次是鼩鼱12只,占17.1%;核酸检测阳性标本19份,均为首尔病毒,检出率为27.1%,源自祥云县的标本检出率在四个地区中最高(32.0%)。从鼠肺标本中扩增得到8条汉坦病毒S节段全基因序列,相似性为87.0%~99.7%,遗传进化分析显示基因序列聚集形成2个分支,一个分支属于S1亚型,另一个分支在遗传进化分析和blast比对分析中与其他亚型同源性均小于90%,属首尔病毒中独立的新的遗传进化分支,提示了云南省鼠类动物间多基因亚型首尔汉坦病毒流行,应进一步关注由宿主动物溢出感染人的潜力。     

Evidence for plant viruses in the region of Argentina Islands, Antarctica

This work focused on the assessment of plant virus occurrence among primitive and higher plants in the Antarctic region. Sampling occurred during two seasons (2004/5 and 2005/6) at the Ukrainian Antarctic Station 'Academician Vernadskiy' positioned on Argentina Islands. Collected plant samples of four moss genera (Polytrichum, Plagiatecium, Sanionia and Barbilophozia) and one higher monocot plant species, Deschampsia antarctica, were further subjected to enzyme-linked immunosorbent assay to test for the presence of common plant viruses. Surprisingly, samples of Barbilophozia and Polytrichum mosses were found to contain antigens of viruses from the genus Tobamovirus, Tobacco mosaic virus and Cucumber green mottle mosaic virus, which normally parasitize angiosperms. By contrast, samples of the monocot Deschampsia antarctica were positive for viruses typically infecting dicots: Cucumber green mottle mosaic virus, Cucumber mosaic virus and Tomato spotted wilt virus. Serological data for Deschampsia antarctica were supported in part by transmission electron microscopy observations and bioassay results. The results demonstrate comparatively high diversity of plant viruses detected in Antarctica; the results also raise questions of virus specificity and host susceptibility, as the detected viruses normally infect dicotyledonous plants. However, the means of plant virus emergence in the region remain elusive and are discussed.     

Inheritance of resistance to potyviruses in Phaseolus vulgaris L. IV. Inheritance, linkage relations, and environmental effects on systemic resistance to four potyviruses

We have examined the genetics of systemic resistance in Phaseolus vulgaris to azuki bean mosaic virus (AzMV) and cowpea aphid-borne mosaic virus (CABMV) and the relationship of this resistance to a phenotypically similar resistance to watermelon mosaic virus (WMV) and soybean mosaic virus (SMV). In P. vulgaris cv Great Northern 1140 (GN1140), resistance to SMV and WMV has been attributed to the genes Smv and Wmv, respectively, which have been shown to segregate as a unit. Systemic resistance to AzMV is conferred by two incompletely dominant alleles, Azm1 and Azm2, at unlinked loci. At least three resistance alleles must be present at these two loci for systemic resistance to be expressed in the plant. Systemic resistance to CABMV in GN 1140 is conditioned by a dominant allele that has been designated Cam2. Under some environmental conditions, a recessive allele at an unlinked locus, cam3, also controls a resistant response to CABMV. Resistance to AzMV and CABMV does not assort independently from Wmv/Smv, but also does not consistently cosegregate, suggesting that perhaps in each case one of the factors involved in resistance is associated with Smv/Wmv.     

Survival of spumavirus,a primate retrovirus,in laboratory media and water

The persistence of a previously characterized spumavirus strain (strain SV-522) was investigated utilizing various laboratory media and waters, including Eagle's minimal essential medium (EMEM) plus 0% fetal bovine serum (EMEM-0%), EMEM-2%, EMEM-10%, Chlamydia transport medium (CTM), phosphate-buffered saline, distilled, estuarine, and marine water, human serum, and the germicides, ethyl alcohol (70%) and sodium hypochlorite (10%). Experiments were performed at 4 degrees C and/or 23 degrees C. Infectivity endpoints were determined in stock aliquots upon initiation of testing and then after 3, 5, 7, and 10 days. The virus was reisolated from all diluents after 5 days at 23 degrees C and in EMEM-10% after 7 days. The virus was detected in CTM, EMEM-2%, EMEM-10%, and estuarine and marine waters after 7 days at 4 degrees C. Differences in the persistence of the virus may be ascribed to temperature and organic load. Water ionic strengths (e.g., estuarine vs. marine water) had no effect on modifying persistence of viral particles. Infectivity of spumavirus was undetectable after 30 s in 70% ethanol or 10% sodium hypochlorite. After 30 min at 23 degrees C, spumavirus infectivity in normal but not heat-inactivated human serum increased by almost 100-fold. Persistence of infectivity of primate spumavirus after 7 days in media and waters, and the agent's infectious potential in the human host, emphasize a need for cautious recognition during the manipulation of primate cells/organs and in the handling of primates themselves.     

Regeneration of midgut epithelial cell in the silkworm, Bombyx mori, infected with viruses

In the larvae of the silkworm, Bombyx mori, the regeneration of midgut cells infected with a cytoplasmic polyhedrosis virus (CPV), a flacherie virus (FV), and a small DNA virus (SDV) was studied. Large numbers of newly developed cells appeared in the CPV-infected part of the midgut epithelium just before larval molt, and along with their development, the CPV-infected old columnar cells were discharged into the midgut lumen during the molt. On the other hand, in the uninfected portion of the midgut only a few cells developed, and no columnar cells were discharged. Similarly, the marked replacement of midgut epithelial cells during larval molt was also observed in larvae infected with CPV + FV. In the larvae infected with CPV + SDV, the columnar cells lost their regenerative ability, and because of the exfoliation of infected columnar cells, the midgut epithelium consisted mainly of uninfected goblet cells at a late stage of infection. The degree of epithelial regeneration varied with the silkworm strain and the dosage of the virus.     

Control of aphid-vectored and thrips-borne virus spread in lily, tulip, iris and dahlia by sprays of mineral oil, polydimethylsiloxane and pyrethroid insecticide in the field

In this study control of spread by insect vectors of non‐persistent Lily symptomless virus and Lily mottle virus in lily, Tulip breaking virus in tulip, Iris mild mosaic virus, Narcissus latent virus and Iris severe mosaic virus in bulbous iris, and semi‐persistent Dahlia mosaic virus and persistent Tomato spotted wilt virus in dahlia has been evaluated with weekly sprays of mineral oil, beta‐pinene emulsion, polydimethylsiloxane emulsions and pyrethroid insecticide. In lily, beta‐pinene in ‘Wilt Prufgave’ 40% reduction of virus spread. In 1995–97 deltamethrin in ‘Decisgave’ 22–58% reduction. Deltamethrin added to sprays of mineral oil ‘Luxan oil H’ and polydimethylsiloxane (PDMS), e.g. in ‘Dow Corning 36’, efficiently improved control efficacy. The latter was also observed in tulip and dahlia. Mineral oil and deltamethrin gave best control by 81–97% reduction of virus spread at standard spray volumes (6.25 litre ha^?1+0.4 litre ha¹). ‘Luxan oil H’ at 3.125 litre ha^?1 with deltamethrin gave 69–91% control. Efficacy of control by polydimethylsiloxane in ‘Dow Corning 36’ was superior to ‘Luxan anti‐foam’. ‘Dow Corning 36’ with deltamethrin (7+0.4 litre ha^?1) gave satisfactory control (68–87%). In tulip, the control by ‘Dow Corning 36’/deltamethrin sprays proved satisfactory compared with ‘Luxan oil H’/‘Decis’‐sprays. In bulbous iris the efficacy of tested PDMS‐brands was clearly different in favour of ‘Dow Corning 36’. In dahlia mineral‐oil and PDMS‐sprays gave some control of semi‐persistent DaMV (16–24%). This ranged at higher level (65–80%) when deltamethrin was added to the spray mixture. Similar trends were observed in the control of persistent TSWV. The effect of polydimethylsiloxane emulsions in the spectrum of virus‐control agents is described for the first time. The effect of PDMS compared with that of mineral oils and synthetic pyrethroid insecticides is discussed with respect to efficacy, mode of action to prevent virus transmission and possible reduction of bulb weights in vegetatively propagated bulb crops.     

重组痘苗狂犬病毒糖蛋白的构建、表达及其遗传稳定性研究

狂犬病毒糖蛋白基因的痘苗病毒表达质粒 pWS 4在鸡胚细胞内与野生型痘苗病毒天坛株 (痘苗病毒 )同源重组 ,经蚀斑纯化 ,获得表达狂犬病毒糖蛋白基因的重组痘苗病毒 (重组病毒 )。该重组病毒DNAdotblot显示强阳性信号 ,间接免疫荧光试验胞膜及胞浆均见到强阳性荧光反应 ,Westernblot分析仅在 6 4ku处呈现一条狂犬病毒非融合性糖蛋白带。免疫小鼠和狗 ,第 2 8d抗狂犬病毒中和抗体滴度分别达 2 4 30和 >6 96。初免后 14d用 5 0～ 10 0LD50 狂犬病毒CVS株对小鼠脑内攻击 ,保护率达 80 %以上。致病性明显减弱。从第 11代起连续传至 30代 ,病毒纯度、病毒滴度、血凝滴度、蛋白的表达、抗原活性和保护性均无差异 ,说明该重组病毒有良好的遗传稳定性。     

Genetically determined nonsusceptibility of the silkworm,Bombyx mori,to infection with a densonucleosis virus (Densovirus)

A nonsusceptible and a highly susceptible strain of the silkworm, Bombyx mori, to peroral infection with a densonucleosis virus (DNV) were studied by probit analysis. Tests with the susceptible and nonsusceptible parent strains, their reciprocal F₁ hybrids, the F₂ hybrid, and the backcrossed hybrids to either of the parents demonstrated that the nonsusceptibility of the silkworm to DNV was inherited and controlled by a recessive gene which was not sex-linked.     

百合病毒的DNA芯片检测技术研究

根据已知的黄瓜花叶病毒,百合无症病毒、百合斑驳病毒基因核苷酸序列,设计引物和探针,制备寡核苷酸芯片。用Cy3标记核苷酸引物,不对称RT-PCR扩增产物与芯片上的寡核苷酸探针杂交,荧光扫描仪检测并分析信号。研究制备的基因芯片能够检测侵染百合的3种重要病毒核酸的特异性荧光信号,该项技术具有特异、灵敏、快速的优点。     

Functional differences between occluded and nonoccluded viruses of a nuclear polyhedrosis of the silkworm, Bombyx mori.

Comparative infectivity and virus neutralization studies on occluded and nonoccluded viruses of Bombyx mori nuclear polyhedrosis revealed that the infectious unit causing peroral infection differed from that causing hemocoelic infection. There were functional differences between the occluded (mainly virons with envelopes) and the nonoccluded virus (mainly virions without envelopes) preparations. The peroral infection was largely due to the virion with an envelope (peroral infectious unit), and the hemocoelic infection was due largely to the virion without an envelope (hemocoelic infectious unit). The apparent change of the virions with envelope to those without envelopes was detected as a slight increase in hemocoelic infectivity when the occluded virus was diluted and incubated at 4°C for more than 6 days.     

The incidence and distribution of viruses infecting lettuce, cultivated Brassica and associated natural vegetation in Spain

A virus survey was conducted during the spring and autumn of 2001 and 2002 to determine the presence, prevalence and distribution in Spain of the viruses that are most commonly found infecting lettuce and Brassica worldwide. Crop plants showing virus symptoms from the principal lettuce and Brassica-growing regions of Spain, and some samples of the annual and perennial flora nearby, were tested by enzyme-linked immunosorbent assays using specific commercial antibodies against the following viruses: Alfalfa mosaic virus (AMV), Broad bean wilt virus 1 (BBWV-1), Beet western yellows virus (BWYV), Cauliflower mosaic virus (CaMV), Cucumber mosaic virus (CMV), Lettuce mosaic virus (LMV), Pea seed-borne mosaic virus (PSbMV), Turnip mosaic virus (TuMV) and Tomato spotted wilt virus (TSWV). Samples were also tested with a Potyvirus genus antibody. Virus incidence was much lower in spring than in autumn, especially in 2001. In spring 2002, CMV and LMV were the most prevalent viruses in lettuce, while CaMV was the most important virus present in Brassica crops grown in Navarra, followed by CMV and BWYV. In the autumn, the spectrum of viruses was different; potyviruses were widespread in lettuce grown in Madrid, but TSWV and BWYV were predominant in the Murcia region. The prevalent Potyvirus detected in lettuce fields was LMV, but none of the samples collected were positive for PSbMV or TuMV. In Brassica crops, TSWV was the most abundant in autumn-sown crops, especially in the Navarra region. All of the viruses present in lettuce and Brassica were also frequently detected in their associated natural vegetation at the same time, suggesting that they probably play an important role as virus reservoirs. Sonchus spp. were particularly common and were frequently infected with CMV, LMV and BWYV. Another common species, Chenopodium album, was often infected with TSWV and BWYV. Multiple infections were common, especially in non-crop plants, and the most common combination was BWYV and TSWV. The role of weeds in the epidemiology of viruses that infect lettuce and Brassica crops in Spain is discussed.     

2006年广州登革热病原体的分离鉴定及其生物学性质的观察

目的：对2006年广州流行登革热病原进行分离鉴定及生物学性质研究。方法：采用传代蚊细胞微量培养方法对2006年广州登革热病原进行分离,并通过脑内途径观察其对乳鼠的致病性;经间接免疫荧光和RT-PCR技术,对患者血清标本中的病毒特异抗体及新分离的病原体进行检测和鉴定;将此次分离的病原体与1980年分离的同型毒株进行生物学性质比较。结果：从57份患者血清标本中分离出10株病毒,在传代蚊细胞中可产生稳定的细胞病变并对乳鼠致病;其基因组为登革1型病毒特异的RNA分子,经鉴定为登革1型病毒;此次分离的登革1型病毒与1980年分离的同型毒株在致细胞产生病变的时间和严重程度,蚀斑的大小、形态以及致乳鼠发病的时间等生物学性质上有所不同。结论：2006年广州流行登革热病原为登革1型病毒,且与1980年分离的同型毒株在生物学性质方面存在明显差异。     

Detection of measles,mumps and rubella viruses by immuno‐colorimetric assay and its application in focus reduction neutralization tests

Measles, mumps and rubella are vaccine‐preventable diseases; however limited epidemiological data are available from low‐income or developing countries. Thus, it is important to investigate the transmission of these viruses in different geographical regions. In this context, a cell culture‐based rapid and reliable immuno‐colorimetric assay (ICA) was established and its utility studied. Twenty‐three measles, six mumps and six rubella virus isolates and three vaccine strains were studied. Detection by ICA was compared with plaque and RT‐PCR assays. In addition, ICA was used to detect viruses in throat swabs (n = 24) collected from patients with suspected measles or mumps. Similarly, ICA was used in a focus reduction neutralization test (FRNT) and the results compared with those obtained by a commercial IgG enzyme immuno assay. Measles and mumps virus were detected 2 days post‐infection in Vero or Vero‐human signaling lymphocytic activation molecule cells, whereas rubella virus was detected 3 days post‐infection in Vero cells. The blue stained viral foci were visible by the naked eye or through a magnifying glass. In conclusion, ICA was successfully used on 35 virus isolates, three vaccine strains and clinical specimens collected from suspected cases of measles and mumps. Furthermore, an application of ICA in a neutralization test (i.e., FRNT) was documented; this may be useful for sero‐epidemiological, cross‐neutralization and pre/post‐vaccine studies.     

Characterization of Viruses Infecting Potato Plants from a Single Location in Shetland,an Isolated Scottish Archipelago

Sequence data were obtained from 29 isolates of Potato virus A (PVA), Potato virus S (PVS), Potato virus V (PVV) and Potato virus X (PVX) infecting nine tubers from Shetland, one of the most remote inhabited islands in the United Kingdom. These isolates were sequenced in the coat protein region, as were 29 Scottish mainland isolates of the same four potato virus species, and these 58 isolates were compared to previously published sequence data. This has allowed the characterization of viruses from a relatively isolated location, where there is little production of ware potatoes and no seed potato production. Phylogenetic homogeneity of the Shetland isolates of PVS and PVV was apparent. PVX was more heterogeneous, and Shetland isolates cluster with the Scottish isolates in a group which includes Asian and European isolates. For PVA, the majority of the Shetland and Scottish mainland isolates formed a predominantly Scottish grouping, with the remaining Shetland and Scottish mainland isolates clustering with a previously characterized Scottish isolate. There were three main groups of PVA, of which the Scottish grouping was the only one which did not have a fully characterized representative. To extend the characterization of PVA, the nucleotide sequence of the full polyprotein region encoding all the gene products of an isolate from Shetland was determined.     

HBx-EGFP-TLM融合蛋白表达载体的构建、蛋白表达纯化及活性检测

乙型肝炎病毒X蛋白 (HBx) 具有广泛的转录激活作用,但是由于细胞类型和实验条件的差异,外源启动子介导的HBx瞬时表达水平常表现出不均一性,为其功能的研究带来困难。为了解决HBx研究过程中遇到的这些难题,利用PCR扩增获得HBx及含转导肽TLM的EGFP编码序列,经酶切后插入pGEX-4T-1原核表达载体,成功构建重组质粒pGEX-HBx-EGFP-TLM和pGEX-EGFP-TLM。重组质粒转化大肠杆菌BL21(DE3) 感受态细胞,融合蛋白经IPTG诱导表达,采用?KTATM Purifier 蛋白纯化系统纯化并进行SDS-PAGE和Western blotting分析,确定为目的蛋白。将纯化后的融合蛋白分别与AML12和SMMC-7721细胞共孵育,Western blotting和激光共聚焦显微镜检测证实TLM转导肽能够介导HBx-EGFP和EGFP进入细胞,同时进入细胞的HBx-EGFP-TLM能够发挥转录激活活性,为HBx功能的深入研究奠定了基础。