杆状病毒包埋型病毒粒子研究进展

杆状病毒是一类专一性感染节肢动物的病原微生物,在其生活周期中产生两种不同形态的病毒粒子,即芽生型病毒粒子和包埋型病毒粒子。自然界中,杆状病毒通过经口感染的方式在其宿主的中肠中建立原发性感染,杆状病毒的包埋型病毒粒子在此过程中发挥关键作用。本文回顾了杆状病毒的基本特性,阐述杆状病毒包埋型病毒粒子的蛋白组成及分类,并着重介绍多粒包埋型病毒粒子的进化及在杆状病毒经口感染过程建立中的意义,对进一步了解杆状病毒的进化历程和侵染机制具有重要的指导意义。     

在系统侵染的烟草中假重组体病毒FMF的时序变化

构建了由黄瓜花叶病毒Fny株系RNA1、RNA3与M株系RNA2组合得到的假重组体病毒FMF,并用其侵染烟草幼苗,接种5 d后烟草幼叶上出现坏死环斑,接种5-30 d新生叶上没有呈现任何明显症状;30 d后新生叶上突然出现轻微绿斑驳。采用实时荧光定量PCR(FQ-PCR)方法,监测不同时期展开的幼叶中病毒粒子含量和病毒基因组RNA含量的动态变化,结果显示,接种后5-25 d新生叶中病毒粒子含量保持较低水平,30 d时含量突然大幅度增长;接种后5-30 d新生叶中病毒基因组RNA1、RNA3和RNA4含量均经历骤减期和增长期;RNA2含量变化情况平缓,没有明显先减后增的趋势。病毒粒子、病毒基因组RNA含量及病症严重程度的动态变化规律及其相关性将为研究FMF侵染机制、病毒与寄主互作及病毒防控提供依据。     

我国一些地区发生的小麦土传病毒病的病原研究

我国浙江、江苏、四川等省发生的小麦土传病毒病,由禾谷多粘菌(Polymyxa graminis)传播,只感染小麦,感病植株幼叶表现为退绿到黄化的条斑,老叶表现为花叶和坏死。我们提纯各地分离物研究表明,病毒粒子呈线状,直径13～14nm,长度为200～1800nm,其中350～850nm的比例较高。病毒外壳由二种分子量分别约为30kd和27kd的结构蛋白组成。病毒粒子周围能均匀地“修饰”小麦梭条斑花叶病毒(WSSMV)抗血清和小麦黄花叶病毒(WYMV)抗血清,反应均很强烈。鉴于上述特性,认为本病害是由小麦棱条斑花叶病毒(WSSMV)引起的。     

黄地老虎质型多角体病毒病的研究

黄地老虎质型多角体病毒的多角体有两种类型：多角形和四边形,大小分别为0.6—2.7μ和0.7—2.8μ。病毒粒子近球形,外壳上有管状物,病毒粒子大小为50—70nm。黄地老虎质型多角体的毒力较高,用1×108多角体／ml的浓度感染3龄幼虫,死亡率达93．9％。石腊切片观察感染6和10天的黄地老虎幼虫,中肠柱状细胞和围食膜内都含有大量多角体。超薄切片观察感染2、4、7天的柱状细胞内形成病毒粒子和多角体。杯状细胞感染较柱状细胞晚。感染4天的围食膜内发现有带毛的游离病毒粒子。     

亚洲小车蝗痘病毒形态及发育研究(英语)

本文报道亚洲小车蝗痘病毒感染黄胫小车蝗引起的病理学变化.该病毒主要感染寄主脂肪体,其次为血细胞.球状体有3种类型:大球体、椭球体和小球体,大小分别为30.41μm×25.40μm、6.58μm×4.78μm和3.35μm×2.60μm.病毒粒子为椭球形,大小为230 nm×176 urn,囊膜表面具有球状亚单位,直径为16nm,使病毒粒子看上去似桑椹,侧体为圆筒形,髓核内绳索状物质似有2折,在横切面上是2个圆点.病毒粒子的发育包括以下4个主要阶段:病毒发生基质的产生;球状颗粒的形成;内核和侧体的分化;髓核和衣壳的进一步分化.成熟病毒粒子逐渐包入球状体.该病毒可感染同属蝗虫.     

鼠痘病毒的分离鉴定及感染性研究

分别从自然感染死亡的小鼠不同病理组织内分离到一种大小为250～300nm×160～190nm 的卵圆型病毒粒子.以腹腔注射的方式将纯化的病毒粒子回复接种到小鼠体内,能引起小鼠死亡,从不同的病理组织内分离到与接种病毒粒子相同的病毒粒子.病理组织的超薄切片电镜观察结果表明在肝、肺、脾、肠等组织的细胞质内均能观察到病毒粒子的存在,表明病毒的复制和装配是在细胞质内完成的,该病毒应归类于痘病毒科.     

鼠痘病毒的分离鉴定及感染性研究

分别从自然感染死亡的小鼠不同病理组织内分离到一种大小为250～300nm×160～190nm的卵圆型病毒粒子。以腹腔注射的方式将纯化的病毒粒子回复接种到小鼠体内,能引起小鼠死亡,从不同的病理组织内分离到与接种病毒粒子相同的病毒粒子。病理组织的超薄切片电镜观察结果表明在肝、肺、脾、肠等组织的细胞质内均能观察到病毒粒子的存在,表明病毒的复制和装配是在细胞质内完成的,该病毒应归类于痘病毒科。     

水稻矮缩病病毒粒子装配模型

水稻矮缩病病毒(RDV)具有多种蛋白质和RNA构成的核衣壳结构, 但是特异性的RNA与蛋白质、蛋白质与蛋白质之间的相互作用和结合, 即有关病毒粒子的装配机理还没有完全阐明. 从细胞内和细胞外两个研究层次详细研究了RNA与蛋白质相互结合情况, 研究发现, P7蛋白能特异并牢固地与RDV基因组的全部12条双链RNA结合; 推定为RNA聚合酶的P1蛋白、鸟苷酰转移酶的P5蛋白和P7蛋白被包裹在病毒核内, 根据体外结合实验, 它们能与病毒转录产物mRNA结合; 从病毒感染的组织中能够提取得到完整的、有感染活性的病毒粒子, 以及缺失P1, P5, P7蛋白和基因组双链RNA, 没有感染活性的空壳病毒粒子; 在病毒粒子中P7蛋白能够与P1蛋白和P3内衣壳蛋白形成蛋白复合物. 这些结果揭示了RDV病毒粒子装配的一种可能的模型, 即核心蛋白和病毒mRNA首先相互结合形成一个整体, 以筛选和富集病毒RNA, 接着包装成为完整的、具有感染活性的病毒粒子.     

1996年中国对虾暴发性流行病病毒病原研究

１９９６年６月至８月,青岛地区养殖的中国对虾大面积暴发流行病,死亡率达９０％以上。发病对虾典型表征为甲壳白斑。病虾鳃组织匀浆滤液经微孔滤膜过滤除菌后,注射给健康对虾进行人工感染试验,９天内累计死亡率达１００％,发病症状及体征与自然发病对虾相似。电镜下自然发病对虾鳃、胃、头胸甲下表皮、淋巴样器官、触角腺等组织细胞核内发现大量杆状病毒,未见包涵体;人工感染对虾相同组织中可见大量同样病毒。切片中病毒粒子     

HaNPV在宿主内的复制及其对宿主蛋白质代谢的影响

对棉铃虫Helicoverpaarmigera的中肠、血淋巴及脂肪体进行SDS-PAGE蛋白质分析表明：感染早期,HaNPV对棉铃虫的蛋白质合成有刺激作用,晚期则表现出抑制作用。感染96 h和120 h脂肪体有较高水平的多角体蛋白合成。电镜观察表明：①HaNPV感染棉铃虫除病毒在中肠复制后经出芽进入血腔感染脂肪体等组织外,还可能存在病毒粒子直接经中肠进入血腔而感染脂肪体这样的途径;②中肠与血腔之间存在屏障结构;③中肠不仅是一次感染时病毒粒子复制的场所,它完全可能被病毒粒子二次感染。在中肠细胞中没有发现多角体的形成。     

Black abalone (Haliotis cracherodii) population structure shifts through deep time: Management implications for southern California's northern Channel Islands

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Abalone I: Analyzing Mark-Recapture-Recovery Data Incorporating Growth and Delayed Recovery

Abalone are semimobile marine gastropods that form the basis of Australia's second most valuable fishery. A site off the coast of Port Arthur, Tasmania, was visited on six occasions. On each occasion, any unmarked live abalone found were marked with a unique identification number and were recorded. Any previously marked abalone found had its identification number and whether or not it was still alive recorded. This results in integrated mark-recapture-recovery data, as in Catchpole et al. (1998, Biometrics 54, 33-46). During the study period, abalone grew in size, and we model the survival of individuals as a function of their size, estimated from a fitted growth curve. The shells of dead animals are long lasting, and we extend existing methodology to allow for the possibility that an animal found dead may have been dead but overlooked for several visits.     

Ontogenetic shift in susceptibility to predators in juvenile northern abalone, Haliotis kamtschatkana

Predation has been suggested as a major cause of juvenile mortality in benthic marine invertebrates. However, the extent to which juveniles are susceptible to predators is unknown for most species, and it remains unclear to what extent ontogenetic shifts in susceptibility to predators are common among marine invertebrates. This study examined the northern abalone Haliotis kamtschatkana, a species listed as threatened in British Columbia, Canada. Our goals were to characterize the diversity and abundance of species that prey on juvenile abalone and determine if abalone experience an ontogenetic shift in susceptibility to predators. Juvenile H. kamtschatkana were found to be susceptible to a broad variety of predators: 14 of the 37 potential predator species to which we offered juvenile abalone (≤ 28 mm shell length (SL)) consumed at least one juvenile abalone. Four of those species (three crabs and one seastar) consumed ≥ 10% of the juvenile abalone that were offered in the laboratory. These species were present at field sites where abalone are found, indicating that they have the potential to be significant predators of juvenile H. kamtschatkana in the wild. The most abundant predators were small crabs, especially Lophopanopeus bellus (black-clawed crabs) and Scyra acutifrons (sharp-nosed crabs). Juvenile H. kamtschatkana also experienced a pronounced ontogenetic shift in susceptibility to predators. The risk of predation for juvenile H. kamtschatkana decreased rapidly with increasing body size, especially over the 12–13 mm SL size range. Susceptibility remained low beyond 13 mm SL, indicating relatively low and unchanging levels of predation risk once the individual reaches this size. Although abalone are susceptible to several species during the first 1–2 years of life, predator effects on juvenile abalone abundance and microhabitat use may largely be attributable to the influence of only 1 or 2 predator species that can only kill abalone < 13 mm SL.     

Movement of the Southern Australian abalone Haliotis laevigata in relation to crevice abundance

The long-term movement of the abalone Haliotis laevigata was measured at three sites in Waterloo Bay, South Australia, characterized by differing amounts of available crevice space. Movement was negligible at a site where crevices were abundant, but extensive at a site without crevice space. At a site of limited available crevice space, the amount of movement increased as available crevice space decreased. In addition, the extent of movement was size dependent and movement was oriented in the direction of the approaching swell. Current experimental designs for measuring natural mortality of abalone depend heavily on assumptions about their movement. An understanding of this behaviour is thus a prerequisite for designing experiments to measure the mortality rates of abalone or other sedentary animals. The natural mortality rate at one site was estimated to be 0.59 (s.e.m. = 0.02, i.e. survival = 56% per year) and the disappearance rate (natural mortality and emigration) was independent of sex.     

Characterization of mucus-associated proteins from abalone (Haliotis) - candidates for chemical signaling

Living in groups is a widespread phenomenon in the animal kingdom. For free-spawning aquatic animals, such as the abalone (Haliotis), being in the close proximity to potential mating partners enhances reproductive success. In this study, we investigated whether chemical cues could be present in abalone mucus that enable species-specific aggregation. A comparative MS analysis of mucus obtained from trailing or fixed stationary Haliotis asinina, and from seawater surrounding aggregations, indicated that water-soluble biomolecules are present and that these can stimulate sensory activity in conspecifics. Purified extracts of trail mucus contain at least three small proteins [termed H.?asinina mucus-associated proteins (Has-MAPs)-1-3], which readily diffuse into the surrounding seawater and evoke a robust cephalic tentacle response in conspecifics. Mature Has-MAP-1 is approximately 9.9 kDa in size, and has a glycine-rich N-terminal region. Has-MAP-2 is approximately 6.2 kDa in size, and has similarities to schistosomin, a protein that is known to play a role in mollusc reproduction. The mature Has-MAP-3 is approximately 12.5 kDa in size, and could only be identified within trail mucus of animals outside of the reproductive season. All three Has-MAP genes are expressed at high levels within secretory cells of the juvenile abalone posterior pedal gland, consistent with a role in scent marking. We infer from these results that abalone mucus-associated proteins are candidate chemical cues that could provide informational cues to conspecifics living in close proximity and, given their apparent stability and hydrophilicity, animals further afield.     

Effects of dietary vitamin K on survival, growth, and tissue concentrations of phylloquinone (PK) and menaquinone-4 (MK-4) for juvenile abalone, Haliotis discus hannai Ino

The experiment was conducted to investigate the effects of dietary vitamin K on survival, growth and tissue vitamin K concentrations of abalone, Haliotis discus hannai. Eight purified diets were formulated to provide a series of graded levels of menadione sodium bisulfite (MSB) (0-320 mgkg(-1) diet). The brown alga, Laminaria japonica, was used as a control diet. Abalone juveniles of similar size (mean weight 1.18+/-0.04 g; mean shell length 18.65+/-0.18 mm) were distributed in a flow-through system using a completely randomized design with nine treatments and three replicate groups per treatment. Animals were hand-fed the appropriate diets once daily at 17:00 for a 120-day period. Survival and carcass composition were not significantly affected by the dietary treatments (P>0.05). Significantly lower growth rate was found in abalone fed diet supplemented with antibiotic (suphaguanidine) than in those fed the other diets, but no significant difference in growth rate related to dietary level of MSB was observed. The concentrations of menaquinone-4 (MK-4) in muscle and viscera increased with increasing dietary MSB up to 10 mgkg(-1). No phylloquinone (PK) was detected in tissues except that the abalone fed the control diet, Laminaria japonica, produced a relatively high level of PK. It seemed to be that the 10-mg MSBkg(-1) diet is sufficient to that allowing the maintenance of 'steady-state' tissue concentration in juvenile abalone. Dietary MSB was converted to MK-4 in abalone. Either MK-4 or PK deposited in the body is derived from food.     

Immunological changes in response to herpesvirus infection in abalone Haliotis laevigata and Haliotis rubra hybrids

Australian abalone production has been affected by outbreaks of abalone viral ganglioneuritis (AVG) caused by a herpesvirus (AbHV). In this study, we undertook experimental transmission trials by immersion to study the abalone immune response to infection with AbHV. Representative cellular and humoural immune parameters of abalone, including total haemocyte count (THC), superoxide anion (SO) and antiviral activity against herpes simplex virus type 1 (HSV-1), were examined in apparently healthy (sub-clinical) and moribund abalone after challenge. In the early infection, sub-clinical stage (days 1–3), THC was found to increase significantly in infected abalone. TaqMan qPCR confirmed 20.5% higher viral load in moribund abalone compared to apparently healthy abalone, indicating that the abundance of AbHV within abalone is linked to their clinical signs. At the clinical stage of infection, THC was significantly lower in moribund abalone, but increased in AbHV-exposed but apparently healthy abalone, in comparison to non-infected controls. SO was reduced in all abalone that were PCR-positive for AbHV. THC and SO level were found to be negatively correlated with the presence of AbHV in abalone, but no effect of AbVH exposure was observed on the haemolymph antiviral activity. These results suggest that abalone mount an initial cellular immune response to AbHV infection, but this response cannot be sustained under high viral loads, leading to mortality.     

Population dynamics can be more important than physiological limits for determining range shifts under climate change

Evidence is accumulating that species' responses to climate changes are best predicted by modelling the interaction of physiological limits, biotic processes and the effects of dispersal‐limitation. Using commercially harvested blacklip (Haliotis rubra) and greenlip abalone (Haliotis laevigata) as case studies, we determine the relative importance of accounting for interactions among physiology, metapopulation dynamics and exploitation in predictions of range (geographical occupancy) and abundance (spatially explicit density) under various climate change scenarios. Traditional correlative ecological niche models (ENM) predict that climate change will benefit the commercial exploitation of abalone by promoting increased abundances without any reduction in range size. However, models that account simultaneously for demographic processes and physiological responses to climate‐related factors result in future (and present) estimates of area of occupancy (AOO) and abundance that differ from those generated by ENMs alone. Range expansion and population growth are unlikely for blacklip abalone because of important interactions between climate‐dependent mortality and metapopulation processes; in contrast, greenlip abalone should increase in abundance despite a contraction in AOO. The strongly non‐linear relationship between abalone population size and AOO has important ramifications for the use of ENM predictions that rely on metrics describing change in habitat area as proxies for extinction risk. These results show that predicting species' responses to climate change often require physiological information to understand climatic range determinants, and a metapopulation model that can make full use of this data to more realistically account for processes such as local extirpation, demographic rescue, source‐sink dynamics and dispersal‐limitation.     

Eisenia arborea J.E. Areschoug as abalone diet on an IMTA farm in Baja California,México

Recent progress in the domestication of Eisenia arborea lead us to test this species as an alternative to feed red abalone (Haliotis rufescens) instead of Macrocystis pyrifera, which is the main seaweed used to feed farmed abalone in Baja California, Mexico. E. arborea is the kelp with the largest and most southerly latitudinal distribution on the North Pacific East Coast capable of growing at higher temperatures and in relatively low nutrient conditions. The availability of M. pyrifera is frequently uncertain because it is strongly affected by El Niño events. In order to test E. arborea as a diet for farmed abalone, animals of two different sizes (6 and 2 cm) were fed separately for 12 months with these two seaweed species. The abalones were cultured in cages in an integrated multi-trophic aquaculture farm within San Quintín Bay, Baja California, Mexico. Seaweed was collected for chemical analysis, and every 3 months, animals were measured and weighed to estimate growth. Small size abalone doubled their size on both diets, with an average increase in length of 2.2 mm month^?1. No significant differences were observed between both treatments. Large abalone fed with M. pyrifera had slighter higher growth rates compared to those fed with E. arborea (0.57 and 0.50 % day^?1, respectively). Although M. pyrifera appeared to be a better diet for large animals, the growth rates obtained with E. arborea and the fact that this species could be cultivated in warmer conditions makes this seaweed species a good candidate to feed farmed abalone.