猪流行性腹泻病毒S蛋白胞内区线性B细胞表位最小基序鉴定

【背景】S蛋白是猪流行性腹泻病毒(Porcine Epidemic Diarrhea Virus,PEDV)的主要结构蛋白和免疫原性蛋白,在前期的研究中,本课题组在S蛋白的胞内区鉴定到2个包含线性B细胞表位的短肽。【目的】鉴定PEDV S蛋白胞内区线性B细胞表位的最小基序。【方法】原核表达2个短肽的每次后移1个氨基酸的系列8肽,以兔抗S蛋白血清为一抗,通过Western Blot筛选阳性反应8肽,鉴定S蛋白胞内区线性B细胞表位的最小基序。【结果】S蛋白胞内区的2个包含线性B细胞表位的短肽共享一个表位,该表位的最小基序为¹³⁷¹QPYE¹³⁷⁴。同源性分析显示该B细胞表位基序为保守性表位。【结论】确定了S蛋白胞内区线性B细胞表位的最小基序为¹³⁷¹QPYE¹³⁷⁴;S蛋白抗原表位的鉴定有助于提高对其结构和功能的理解。     

石灰岩特有植物圆叶乌桕叶表皮形态特征及其生态适应性研究

采用扫描电子显微镜和光学显微镜,对石灰岩特有植物圆叶乌桕与同属的乌桕、山乌桕的叶表皮微形态进行观察,比较3个种的叶表皮形态特征,分析圆叶乌桕在石灰岩地区生长的环境适应特点。结果表明:圆叶乌桕叶下表皮细胞小且呈无规则型,细胞排列紧密;气孔集中分布于下表皮,气孔密度和气孔指数相对最小;气孔类型是无规则型,无副卫细胞;圆叶乌桕上下叶表皮有厚角质层和蜡质层,蜡被呈片状和网状。圆叶乌桕的叶表皮微形态特征反映了它对石灰岩生境的适应性较强。     

植物病原真菌致病毒素草酸的研究进展

许多植物病原菌可以分泌草酸,草酸作为致病的关键因子在病原菌的侵染过程中发挥着重要作用,并与病原菌的致病性、毒性有密切关系。草酸可通过氧化和脱羧两条途径进行降解,因此可以将草酸降解酶基因导入植物,从而获得对这类病害的抗性。     

Early detection surveillance for an emerging plant pathogen: a rule of thumb to predict prevalence at first discovery

Emerging plant pathogens are a significant problem for conservation and food security. Surveillance is often instigated in an attempt to detect an invading epidemic before it gets out of control. Yet in practice many epidemics are not discovered until already at a high prevalence, partly due to a lack of quantitative understanding of how surveillance effort and the dynamics of an invading epidemic relate. We test a simple rule of thumb to determine, for a surveillance programme taking a fixed number of samples at regular intervals, the distribution of the prevalence an epidemic will have reached on first discovery (discovery-prevalence) and its expectation E(q*). We show that E(q*) = r/(N/Δ), i.e. simply the rate of epidemic growth divided by the rate of sampling; where r is the epidemic growth rate, N is the sample size and Δ is the time between sampling rounds. We demonstrate the robustness of this rule of thumb using spatio-temporal epidemic models as well as data from real epidemics. Our work supports the view that, for the purposes of early detection surveillance, simple models can provide useful insights in apparently complex systems. The insight can inform decisions on surveillance resource allocation in plant health and has potential applicability to invasive species generally.     

猪流行性腹泻病毒经其附属蛋白抑制细胞凋亡

【背景】orf3位于猪流行性腹泻病毒(porcine epidemic diarrhea virus,PEDV) s基因与e基因之间,是目前发现的PEDV唯一一个附属基因,编码附属蛋白(ORF3蛋白)。我们前期研究初步发现ORF3蛋白对PEDV诱导的细胞凋亡有影响。【目的】研究ORF3蛋白在PEDV侵染复制过程中的毒力作用机制。【方法】实验用3种PEDV:rDR13att-?ORF3 (orf3基因全部敲除)、DR13-ORF3att (携带有C端截短orf3)、rDR13att-ORF3wt(携带全长orf3基因)感染Vero细胞,观察病变情况,再用活细胞成像仪、流式细胞仪、 DNA断裂的原位末端标记法[terminaldeoxynucleotidyltransferase(TDT)-mediated dUTP nick end labeling,TUNEL]等方法检测不同感染时间点的细胞凋亡情况,然后用蛋白质印迹方法分析PEDV感染宿主细胞中主要凋亡相关蛋白(如Caspase-3)的活化或裂解,最后进行转录组测序研究病毒感染细胞中差异基因的表达情况,再用荧光定量PCR验证转录组结果。【结果】rDR13att-?ORF3引起较多的细胞病变,活细胞成像仪的动态观察结果显示,3种病毒侵染的细胞凋亡水平随着时间的延长均高于正常阴性细胞,但敲除orf3的病毒感染细胞后细胞凋亡率比其他两种病毒更高;敲除orf3病毒感染细胞凋亡率显著高于其他两种病毒;病毒rDR13att-?ORF3感染细胞后TUNEL阳性细胞数比DR13-ORF3att和rDR13att-ORF3wt更多;表达ORF3蛋白的重组PEDV可以抑制Caspase-3的活化;ORF3蛋白对受感染细胞Heat shock 70 kD protein 1B (HSP70)基因转录有促进作用,荧光定量PCR结果表明rDR13att-ORF3wt感染细胞的HSP70表达量高于rDR13att-?ORF3感染细胞。【结论】PEDV通过ORF3蛋白抑制细胞凋亡,而且这种作用可能是通过抑制Caspase-3的活化或增加HSP70的产生来完成的。     

韭菜迟眼蕈蚊发生规律及防治方法研究进展

韭菜迟眼蕈蚊是我国韭菜生产中的重要害虫,各韭菜种植区均有发生。随着北方设施农业的迅速发展,良好的温室环境使韭菜迟眼蕈蚊的为害愈加严重,已成为制约韭菜种植业发展的重要因素。上世纪80年代,分类学家正式确定韭菜迟眼蕈蚊Bradysia odoriphaga是我国韭菜根蛆类害虫的优势物种,此后,在生物学、生理学、生态学等基础研究领域和防治方法等应用研究领域,有关韭菜迟眼蕈蚊的研究都取得了很大进展。本文全面总结了韭菜迟眼蕈蚊在我国各韭菜种植区及不同种植模式下的发生规律,详细叙述了农业、物理、生物、化学等相关防治措施,综合介绍了韭菜迟眼蕈蚊防治方法近二十年内的研究成果,对未来韭菜迟眼蕈蚊的综合治理方向进行了展望。     

Rate of succession in restored wetlands and the role of site context

Question: Are changes in plant species composition, functional group composition and rates of species turnover consistent among early successional wetlands, and what is the role of landscape context in determining the rate of succession? Location: Twenty‐four restored wetlands in Illinois, USA. Methods: We use 4 years of vegetation sampling data from each site to describe successional trends and rates of species turnover in wetlands. We quantify: (1) the rate at which composition changes from early‐successional to late‐successional species and functional groups, as indicated by site movement in ordination space over time, and (2) the rate of change in the colonization and local extinction of individual species. We correlate the pace of succession to site area, isolation and surrounding land cover. Results: Some commonalities in successional trends were evident among sites. Annual species were replaced by clonal perennials, and colonization rates declined over time. However, differences among sites outweighed site age in determining species composition, and the pace of succession was influenced by a site's landscape setting. Rates of species turnover were higher in smaller wetlands. In addition, wetlands in agricultural landscapes underwent succession more rapidly, as indicated by a rapid increase in dominance by late‐successional plants. Conclusions: Although the outcome of plant community succession in restored wetlands was somewhat predictable, species composition and the pace of succession varied among sites. The ability of restoration practitioners to accelerate succession through active manipulation may be contingent upon landscape context.     

植物激素检测技术研究进展

植物激素是植物体内合成的一系列痕量有机化合物,它们在植物的生长发育和环境应答过程中具有非常重要的作用,其超微定量及原位测定技术仍是制约植物激素研究的瓶颈问题之一。该文着重介绍了近年来茉莉酸及其甲酯、脱落酸、生长素、赤霉素和多肽激素等植物激素分析检测技术的最新研究进展,并对植物激素超微量、高灵敏检测技术研究中存在的问题和发展前景进行了简要的讨论。     

中药凌霄花的研究进展

本文对中药凌霄花的研究进展进行了综述,包括生药学研究、化学成分研究、药理学研究及临床应用。     

枇杷果实采后生理与保鲜技术研究进展(综述)

本文综述枇杷果实采后生理与保鲜技术的研究现状,并提出枇杷保鲜技术发展方向。