全球EV-A71的基因型分布

肠道病毒A组71型(EV-A71)是引起手足口病暴发流行的主要病原体,也是除脊髓灰质炎病毒以外最为重要的人肠道病毒病原体。截止2017年2月,全球报道的EV-A71共包括7个基因型(A~G)和14个基因亚型,其中B基因型和C基因型是目前全球流行的优势基因型,目前已鉴定B基因型有8个基因亚型(B0~B7),C基因型有6个基因亚型(C1~C6)。C4基因亚型中C4a进化分支是引起中国大陆近年手足口病大规模暴发流行的主要病原之一,也是引起手足口病重症和死亡的绝对优势病原体。本文对全球流行的EV-A71基因(亚)型的地理和年代分布、新基因型的发现进行了系统的归纳分析,为中国检测和监测引起HFMD流行的EV-A71基因型或亚型的动态变化提供基础数据。     

EV-A71感染导致的重症手足口病的机制及防控研究进展

手足口病(Hand,foot and mouth disease,HFMD)是一种具有高度传染性的病毒性传染病,通常夏秋季高发于幼儿和儿童;若患儿并发呼吸和循环功能障碍、神经系统受累等临床症状称为重症HFMD。少数重症病例可出现肺水肿、脑炎和急性弛缓性麻痹等罕见的神经或循环系统并发症,甚至导致患儿死亡。引起HFMD最常见的病原是肠道病毒A71型(EV-A71)和柯萨奇病毒A16型(CV-A16),而EV-A71是引起重症HFMD的主要病原体。EV-A71导致的重症HFMD已成为全球重要的公共卫生问题,减少EV-A71流行范围和预防EV-A71重症HFMD非常重要。EV-A71疫苗是目前最有效的预防重症HFMD发生的措施;中国已经批准了三个厂家的灭活EV-A71疫苗上市并已开展适龄儿童接种,以期预防EV-A71感染引起的重症HFMD,但这种疫苗不能预防其它肠道病毒如CV-A16,CV-A6和CV-A10等引起的HFMD。据文献报道,小分子抑制剂芦平曲韦可以通过阻止EV-A71的3C pro蛋白活性来抑制EV-A71复制;小干扰RNA和单克隆抗体也可抑制EV-A71复制。研制EV-A71和CVA16双价灭活疫苗是防控HFMD的策略之一,而小分子抑制剂、小干扰RNA和单克隆抗体的研制和应用等也是临床防治HFMD的探索。     

狂犬病毒反向遗传学技术的研究及应用进展

反向遗传学技术是上世纪90年代在分子病毒学研究领域兴起的新技术,通常也被称为“病毒拯救”。综述了应用反向遗传学技术“拯救”狂犬病毒的主要技术体系以及反向遗传学技术在狂犬病毒致病机理、狂犬病毒疫苗及载体研究中的应用进展。     

反向遗传学技术在疫苗研究的进展

本文通过反向遗传学技术的基本原理,发展历史和反向遗传学技术在疫苗研究方面的进展与应用,重点介绍了反向遗传学技术在流感病毒疫苗方面的应用。     

基于杂交链反应的新一代RNA-FISH技术检测EV-A71RNA及其与病毒3D聚合酶的相互作用

RNA荧光原位杂交(RNA-fluorescence in situ hybridization, RNA-FISH)技术利用荧光标记的核苷酸探针,通过互补链杂交,对细胞或组织中特定的RNA序列进行检测和定位。由于RNA-FISH产生的阳性信号较弱,需要结合特异性信号放大,提高信噪比。但传统信号放大技术的背景难以消除,无法定量且分辨率低,是RNA-FISH技术应用的巨大障碍。本文基于第3代杂交链反应(hybridization chain reaction version 3.0,HCR v3.0),利用一对分裂式探针消除非特异杂交背景,并引发荧光信号放大反应,建立了针对肠道病毒A71 (enterovirus-A71, EV-A71) RNA的敏感、特异的FISH检测方法,并将该技术与蛋白免疫荧光(immunofluorescence, IF)检测结合,通过高分辨率激光共聚焦成像,成功地在单个细胞水平上检测了EV-A71感染细胞后病毒RNA与其聚合酶3D蛋白的分布变化和相互作用情况,并对细胞中病毒RNA和3D蛋白进行定量。发现相较于传统定量方法,如逆转录定量聚合酶链反应和免疫印迹,新...     

流感病毒反向遗传学技术研究进展

流感病毒亚型众多,且极易发生变异,给防控带来很大困难,所以当务之急应加强其在致病机理、传播机制等方面的研究和加快新型流感疫苗的开发．近年来,反向遗传学技术的发展为流感病毒基因功能研究和疫苗制备方面开辟了新思路．     

肠道病毒71型(EV-A71)感染ICR小鼠模型的建立

为研究肠道病毒71型(Enterovirus 71,EV-A71)经不同攻毒方式感染不同日龄ICR乳鼠的感染情况,了解EV-A71在小鼠体内的动态分布和感染机制,为建立EV-A71感染动物模型,本研究采用分离自重症手足口患儿的EV-A71毒株,分别通过肌肉注射(Intramuscular injection,IM)、腹腔注射(Intraperitoneal injection,IP)以及脑内注射(Intracerebral injection,IC)的方式感染3日、5日和9日龄ICR乳鼠,感染后定期采集血液和各组织,通过Realtime PCR追踪各组织中病毒载量变化,并且通过切片制作和免疫组化对感染乳鼠进行病原学和病理学分析。结果显示:对于低日龄(≤5日龄)乳鼠,注射剂量在104.5 TCID50/g·体重时IM、IP及IC均为较好的感染方式,都会出现神经症状,且有极高的致死率。随着日龄增长,感染后症状有所减轻,但IM和IP感染途径对大日龄乳鼠仍具有良好的致病性,且IM和IP死亡率显著高于IC死亡率。经IM、IP和IC注射感染病毒的3日龄乳鼠在6dpi体重相对于各对照组分别下降了1.54g(31.43%)、1.31g(15.06%)和2.52g(44.28%),而经IM和IP感染的5日龄乳鼠6dpi体重相对于各对照组分别下降了0.605g(8.95%)、0.886g(15.51%),经IC感染的5日龄乳鼠6dpi体重相对于对照组上升了0.904g(14.70%),感染组体重均显著低于对应的同期对照组(P0.05)。经IM、IP和IC感染病毒的3日龄乳鼠9dpi均死亡,而5日龄乳鼠9dpi存活率分别为42.8%、25%和87.5,14dpi存活率分别为0%、0%和25%,9日龄乳鼠9dpi存活率分别为70%、84.62%和100%。病理学及免疫组化检查显示EV-A71病毒具有强烈的嗜神经性及嗜骨骼肌的特性,可导致病毒血症、脑神经元及骨骼肌坏死、心肌间质水肿及多脏器炎症反应。我们系统地研究了不同攻毒方式感染不同日龄的ICR乳鼠后的病毒动态分布及免疫病理损伤,发现经肌肉注射或腹腔注射5日龄乳鼠能够建立理想的EV-A71感染动物模型。     

反向遗传学技术及其在FMDV研究中的应用

反向遗传技术是一种新兴的分子生物学技术,已广泛应用于生命科学研究的各个领域。综述反向遗传技术研究进展,并讨论该技术在口蹄疫病毒研究中的应用。     

基于质粒的轮状病毒反向遗传学研究进展

轮状病毒是全球范围内引起婴幼儿急性胃肠炎的最主要病原体,2016年导致的儿童死亡病例为228047例,每年导致的住院病例则高达200万例。轮状病毒属于呼肠孤病毒科,基因组由11条分节段的双链RNA (dsRNA)组成,被三层衣壳包裹。病毒反向遗传学技术的建立加快了病毒学的研究。2017年,完全依赖质粒的轮状病毒反向遗传学技术获得突破,随后在轮状病毒致病机制、疫苗研发、载体构建等方面取得重要进展。本文将就此技术的建立、发展和应用进行综述,供相关领域人员参考,以期加快我国轮状病毒的研究和应用,推动我国轮状病毒急性胃肠炎的预防和控制。     

流感病毒的反向遗传学研究进展

反向遗传学是指对病原微生物的cDNA进行目的性修饰,以对其进行功能和表型的分析[1]。它是相对于经典遗传学而言的,后者是从生物的性状、表型到遗传物质来研究生命的发生与发展规律。反向遗传学则是在获得生物体基因组全部序列的基础上,通过对靶基因进行必要的加工和修饰,如定点     

肠道病毒71型(EV71)反向遗传研究进展

反向遗传学技术实现了在DNA分子水平上对RNA病毒基因组的人工操作,在深入阐明基因组结构与功能、筛选研制新型基因工程疫苗及基因治疗等方面显示出良好的应用前景。本文对反向遗传学技术及在肠道病毒71型病毒中的应用进行了综述。1肠道病毒71型基因组结构及复制特征肠道病毒71型(Enterovirus type 71,EV71)是小RNA病毒科肠道属成员,其感染主要引起手足口病,还可能引起严重的神经系统疾病,如脑炎、无菌性脑膜炎和脊髓灰质炎样的麻痹等。根据EV71衣壳蛋白VP1区的核苷酸序列的不同,EV71可以分为A、B、C三个基因型,其中B型和C型又     

The Combination Effects of LiCl and the Active Leflunomide Metabolite,A771726, on Viral-Induced Interleukin 6 Production and EV-A71 Replication

Enterovirus 71 (EV-A71) is a neurotropic virus that can cause severe complications involving the central nervous system. No effective antiviral therapeutics are available for treating EV-A71 infection and drug discovery efforts are rarely focused to target this disease. Thus, the main goal of this study was to discover existing drugs with novel indications that may effectively inhibit EV-A71 replication and the inflammatory cytokines elevation. In this study, we showed that LiCl, a GSK3β inhibitor, effectively suppressed EV-A71 replication, apoptosis and inflammatory cytokines production (Interleukin 6, Interleukin-1β) in infected cells. Furthermore, LiCl and an immunomodular agent were shown to strongly synergize with each other in suppressing EV-A71 replication. The results highlighted potential new treatment regimens in suppressing sequelae caused by EV-A71 replication.     

Landscape genetics of a tropical rescue pollinator

Pollination services are increasingly threatened by the loss and modification of natural habitats, posing a risk to the maintenance of both native plant biodiversity and agricultural production. In order to safeguard pollination services, it is essential to examine the impacts of habitat degradation on the population dynamics of key pollinators and identify potential “rescue pollinators” capable of persisting in these human-altered landscapes. Using a landscape genetic approach, we assessed the impact of landscape structure on genetic differentiation in the widely-distributed tropical stingless bee Trigona spinipes (Apidae: Meliponini) across agricultural landscape mosaics composed of coffee plantations and Atlantic forest fragments in southeastern Brazil. We genotyped 115 bees at 16 specific and highly polymorphic microsatellite loci, developed using next-generation sequencing. Our results reveal that T. spinipes is capable of dispersing across remarkably long distances, as we did not find genetic differentiation across a 200 km range, nor fine-scale spatial genetic structure. Furthermore, gene flow was not affected by forest cover, land cover, or elevation, indicating that reproductive individuals are able to disperse well through agricultural landscapes and across altitudinal gradients. We also found evidence of a recent population expansion, suggesting that this opportunistic stingless bee is capable of colonizing degraded habitats. Our results thus suggest that T. spinipes can persist in heavily-altered landscapes and can be regarded as a rescue pollinator, potentially compensating for the decline of other native pollinators in degraded tropical landscapes.     

Cellular Caspase-3 Contributes to EV-A71 2Apro-Mediated Down-Regulation of IFNAR1 at the Translation Level

Enterovirus A71(EV-A71) is the major pathogen responsible for the severe hand, foot and mouth disease worldwide, for which few effective antiviral drugs are presently available. Interferon-a(IFN-a) has been used in antiviral therapy for decades; it has been reported that EV-A71 antagonizes the antiviral activity of IFN-a based on viral 2 Apro-mediated reduction of the interferon-alpha receptor 1(IFNAR1); however, the mechanism remains unknown. Here, we showed a significant increase in IFNAR1 protein induced by IFN-a in RD cells, whereas EV-A71 infection caused obvious downregulation of the IFNAR1 protein and blockage of IFN-a signaling. Subsequently, we observed that EV-A71 2 Apro inhibited IFNAR1 translation by cleavage of the eukaryotic initiation factor 4 GI(eIF4GI), without affecting IFNAR1 m RNA levels induced by IFN-a. The inhibition of IFNAR1 translation also occurred in puromycin-induced apoptotic cells when caspase-3 cleaved e IF4 GI. Importantly, we verified that 2 Aprocould activate cellular caspase-3, which was subsequently involved in e IF4 GI cleavage mediated by 2 Apro. Furthermore, inhibition of caspase-3 activation resulted in the partial restoration of IFNAR1 in cells transfected with 2 A or infected with EV-A71, suggesting the pivotal role of both viral 2 Aproand caspase-3 activation in the disturbance of IFN-a signaling. Collectively, we elucidate a novel mechanism by which cellular caspase-3 contributes to viral 2 Apro-mediated down-regulation of IFNAR1 at the translation level during EV-A71 infection, indicating that caspase-3 inhibition could be a potential complementary strategy to improve clinical anti-EV-A71 therapy with IFN-a.     

Reverse Genetic Analysis of Adaptive Mutations within the Capsid Proteins of Enterovirus 71 (EV-A71) Strains Necessary for Infection of CHO-K1 Cells

正Dear Editor,Previous studies had described the adaptation of enterovirus 71 (EV-A71) strains that enabled entry and viral replication in Chinese Hamster Ovary (CHO) cell line(Zaini and Mc Minn 2012; Zaini et al. 2012). These adapted     

Examination of a plasmid‐based reverse genetics system for human astrovirus

A plasmid‐based reverse genetics system for human astrovirus type 1 (HAstV1) is examined. Upon transfection into 293T cells, the plasmid vector, which harbors a HAstV1 expression cassette, expressed astroviral RNA that appeared to be capable of viral RNA replication, as indicated by the production of subgenomic RNA and capsid protein expression irrespective of the heterologous 5′ ends of the transcribed RNA. Particles infectious to Caco‐2 cells were made in this system; however, their infectivity was much lower than would be expected from the amount of particles apparently produced. Using Huh‐7 cells as the transfection host with the aim of improving viral capsid processing for virion maturation partially restored the efficiency of infectious particle formation. Our results support the possibility that the DNA transfection process induces a cellular response that targets late, but not early, stages of HAstV1 infection.     

Genetic engineering of rotaviruses by reverse genetics

The rotavirus genome is composed of 11 gene segments of dsRNA. A recent breakthrough in the field of rotaviruses is the development of a reverse genetics system for generating recombinant rotaviruses possessing a gene segment derived from cloned cDNA. Although this approach is a helper virus‐driven system that is technically limited and gives low levels of recombinant viruses, it allows alteration of the rotavirus genome, thus contributing to our understanding of these medically important viruses. So far, this approach has successfully been applied to three of the 11 viral segments in our laboratory and others, and the efficiency of recovery of recombinant viruses has been improved. However, we are still waiting for the development of a helper virus‐free reverse genetics system for generating an infectious rotavirus entirely from cDNAs, as has been achieved for other members of the Reoviridae family.     

Establishment of a reverse genetics system for rotavirus

The rotavirus genome is composed of 11 segments of double-stranded RNA (dsRNA). Rotavirus is the leading etiological agent of severe gastroenteritis in infants and young children worldwide. Reverse genetics is the powerful and ideal methodology for the molecular study of virus replication, which enables the virus genome to be artificially manipulated. Very recently, we developed the first reverse genetics system for rotavirus, which enables one to generate an infectious rotavirus containing a novel gene segment derived from cDNA. In this review, we describe each steps of rotavirus replication to understand the background to the establishment of a reverse genetics system for rotavirus, and summarize the reverse genetics systems for segmented dsRNA viruses including rotavirus.     

Forward and reverse genetics of rapid-cycling Brassica oleracea

Seeds of rapid-cycling Brassica oleracea were mutagenized with the chemical mutagen, ethylmethane sulfonate. The reverse genetics technique, TILLING, was used on a sample population of 1,000 plants, to determine the mutation profile. The spectrum and frequency of mutations induced by ethylmethane sulfonate was similar to that seen in other diploid species such as Arabidopsis thaliana. These data indicate that the mutagenesis was effective and demonstrate that TILLING represents an efficient reverse genetic technique in B. oleracea that will become more valuable as increasing genomic sequence data become available for this species. The extensive duplication in the B. oleracea genome is believed to result in the genetic redundancy that has been important for the evolution of morphological diversity seen in today’s B. oleracea crops (broccoli, Brussels sprouts, cauliflower, cabbage, kale and kohlrabi). However, our forward genetic screens identified 120 mutants in which some aspect of development was affected. Some of these lines have been characterized genetically and in the majority of these, the mutant trait segregates as a recessive allele affecting a single locus. One dominant mutation (curly leaves) and one semi-dominant mutation (dwarf-like) were also identified. Allelism tests of two groups of mutants (glossy and dwarf) revealed that for some loci, multiple independent alleles have been identified. These data indicate that, despite genetic redundancy, mutation of many individual loci in B. oleracea results in distinct phenotypes. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.