番鸭呼肠孤病毒套式RT-PCR检测方法的建立及应用

根据GenBank上发表的鸭呼肠孤病毒基因组序列,利用生物学软件设计合成内外2对引物,建立了检测番鸭呼肠孤病毒(Muscovy duck reovirus,MDRV)的套式RT-PCR检测方法,并运用建立的检测方法对分离病毒与其他禽病病毒进行检测。结果显示,该方法能从MDRV中扩增到与预期大小相符的特异性目的片段,检测灵敏度达到0.1 pg病毒RNA,对禽呼肠孤病毒(avian reovirus,ARV)、鸡传染性法氏囊病病毒(infectious bursal disease virus,IBDV)、番鸭细小病毒(Muscovy duck parvovirus,MDPV)、鹅细小病毒(goose parvovirus,GPV)、鸭病毒性肝炎病毒(duck hepatitis virus,DHV)等病毒样品的扩增结果均为阴性。因此,本研究为番鸭呼肠孤病毒病的快速检测及诊断研究提供参考。     

Sequence and phylogenetic analysis of M-class genome segments of novel duck reovirus NP03

We report the sequence and phylogenetic analysis of the entire M1, M2, and M3 genome segments of the novel duck reovirus (NDRV) NP03. Alignment between the newly determined nucleotide sequences as well as their deduced amino acid sequences and the published sequences of avian reovirus (ARV) was carried out with DNASTAR software. Sequence comparison showed that the M2 gene had the most variability among the M-class genes of DRV. Phylogenetic analysis of the M-class genes of ARV strains revealed different lineages and clusters within DRVs. The 5 NDRV strains used in this study fall into a well-supported lineage that includes chicken ARV strains, whereas Muscovy DRV (MDRV) strains are separate from NDRV strains and form a distinct genetic lineage in the M2 gene tree. However, the MDRV and NDRV strains are closely related and located in a common lineage in the M1 and M3 gene trees, respectively.     

新型鸭呼肠孤病毒QY株S3基因克隆与序列分析

参考GenBank新型鸭呼肠孤病毒（New-type duck reovirus,NDRV）S3基因序列设计合成一对引物,对新型鸭呼肠孤病毒QY株S3基因进行RT-PCR扩增,并对PCR产物进行了克隆和测序.结果显示扩增产物为1 104 bp,与预期的目的片段大小一致.相似性分析QY株S3基因核苷酸序列与ARV代表株、MDRV代表株和DRV代表株,相似性分别59.4％ ～ 60.0％、61.1％～ 61.3％和96.7％～ 98.6％;氨基酸的相似性分别为67.6％～ 68.7％、68.1％～68.9％和95.4％～ 98.4％.表明QY株的S3基因具有不同于ARV和MDRV的特征,分离病毒QY株是不同于禽呼肠孤病毒和番鸭呼肠孤病毒的独立基因群.     

应用RT-PCR技术检测番鸭呼肠孤病毒

参考 Gen Bank中番鸭呼肠孤病毒 (m uscovy duck reovirus,MDRV ) S1基因序列 ,用计算机设计并合成了 1对引物 HP11、HP12 ,以此引物用 RT- PCR对番鸭呼肠孤病毒 S1基因进行了特异性扩增。结果表明 :引物 HP11、HP12能从所有供试的 4株分离毒 MDRV- MW9710、MW980 6、MW980 9、MW9810扩增出 30 0 bp S1基因 c DNA片段 ,而不能从禽呼肠孤病毒 (ARV) S1133株和番鸭胚成纤维 (MDEF)细胞培养物中扩增出任何片段 ;该 RT- PCR的检测灵敏度为 1pg的病毒核酸 ,特异性强 ,重复性好 ,对含毒细胞培养液和尿囊液只需用氯仿进行简单处理 ,即能检测出 MDRV核酸。因此认为 ,该 RT- PCR可以用于番鸭呼肠孤病毒的快速检测     

间接免疫荧光方法快速检测番鸭呼肠孤病毒病

本研究应用具有免疫荧光特性的抗番鸭呼肠孤病毒病单克隆抗体(MDRV 237-11)建立了检测番鸭呼肠孤病毒病抗原的间接免疫荧光(Mab-IFA)方法。结果显示人工感染MDRVMW9710株病毒后发病和死亡番鸭组织切片均可检出阳性病灶;且组织匀浆经尿囊腔途径接种12日龄番鸭胚,取死亡胚心制作冰冻切片进行IFA鉴定呈阳性结果。表明该方法特异性好、可用于快速检测番鸭呼肠孤病毒病。     

番鸭呼肠孤病毒MW9710株S1基因片段的克隆及序列分析

参考GenBank番鸭呼肠孤病毒(muscovy duck reovirus,MDRV)S1基因序列设计合成一对引物,对番鸭呼肠孤病毒MW9710株S1基因进行RT-PCR扩增,并对PCR产物进行了克隆和测序.结果显示扩增产物为300bp,与预期的目的片段大小一致,经PCR、酶切反应鉴定后克隆到pGEM-Teasy载体中,核苷酸序列经BLAST软件分析表明:番鸭呼肠孤病毒MW9170株S1基因的目的片段与番鸭呼肠孤病毒法国89026株同源性为91.7%,与鸡关节炎病毒S2基因同源性为68.7%,结果提示番鸭呼肠孤病毒MW9710株与鸡关节炎病毒亲缘距离较远.     

Suppression of protein expression of three avian reovirus S-class genome segments by RNA interference

RNA interference was used to suppress protein expression of three S-class genome segments of avian reovirus (ARV). Viral progeny titer was successfully down-regulated by RNA interference. Suppression of S1 genome segment, which has three open reading frames, not only decreased the expression level of the structural protein σC but also reduced cell fusion and the level of Ser¹⁵-phosphorylated p53 protein caused by the nonstructural proteins p10 and p17, respectively. Suppression of S2 or S4 genome segment by RNA interference could also reduce the expression level of σA or σNS. Interestingly, suppression of σNS resulted in down regulation of the expression of other viral products. In terms of variability of different genes among viral strains and of the impact after their suppression, it seems that the viral products involved in construction of viroplasm or core particles, like σNS, are considerable choices to efficiently inhibit ARV multiplication by RNA interference. Using a GFP reporter system, it was discovered that ARV could not inhibit activated RNA interference, suggesting that RNA interference may be used in the suppression of ARV infection.     

小鹅瘟病毒单克隆抗体的制备及特性鉴定

为了建立快速、简便的番鸭小鹅瘟病诊断方法,用纯化的小鹅瘟病毒（Goose parpovirus,GPV-PT）免疫BABL/c鼠,取脾细胞和骨髓瘤细胞进行融合,经间接ELISA和间接免疫荧光检检（indirect immunofluorescence assay,IFA）筛选,获得3株能稳定分泌抗GPV单克隆抗体的杂交瘤细胞株（分别命名为D11、7-7和E16）。三株单抗的免疫球蛋白亚类分别为IgM、IgG3和IgM,3株单抗均具有ELISA、IFA和中和特性;其中两株（D11和E16）具有致敏胶乳特性;特异性测定显示3株单抗仅与GPV反应,而与番鸭细小病毒（Duck parpovirus,MPV）、番鸭呼肠孤病毒（Muscovy duck reovirus,MDRV）、禽呼肠孤病毒（Avian reovirus,ARV）、鸭副粘病毒（Paramyxovirus,PMV）、鸭肝炎病毒（Duck hepatis virus,DHV）、正常细胞和胚液等均无交叉反应;在-20℃保存期为18个月。结果表明3株单抗均具有良好的特异性,为研制免疫学快速诊断奠定了基础。     

3种禽类呼肠孤病毒血清学相关性及致细胞病变差异分析

本研究旨在研究3种不同疾病型禽类呼肠孤病毒间的抗原性关系及病毒的培养特性。作者通过血清中和试验测定了禽呼肠孤病毒(ARV S1133株)、番鸭呼肠孤病毒(MDRV 9710株)、新型鸭呼肠孤病毒(NDRV NP01株)3种禽类呼肠孤病毒的血清学相关性,统计抗原相关性R值;并应用部分禽胚原代细胞及哺乳动物传代细胞对这3种病毒的培养特性进行了初步研究。结果表明,3种病毒株之间的R值很小,抗原相关性较低;三者具有广泛的细胞亲嗜性,能在多种细胞中增殖,并产生细胞病变,但病毒致细胞病变特征有所差异,ARV和NDRV均以巨融合为主,而MDRV则以细胞圆缩坏死为主。上述结果表明导致禽类不同疾病的ARV、MDRV和NDRV三者之间的抗原相关性较低,病毒的细胞培养特性也不同,细胞病变类型的差别提供了一种初步鉴别禽类呼肠孤病毒的方法。     

番鸭源呼肠孤病毒σC基因的表达与分析

为开展番鸭源呼肠孤病毒(Muscovy duck reovirus,MDRV)σC基因编码蛋白的相关研究,本研究采用RT-PCR技术从MDRV全基因组中扩增σC基因片段,与p ET24a载体连接,构建原核表达重组质粒p ET24a-C,转化BL21(DE3)感受态细胞后,IPTG诱导表达σC重组蛋白;并利用SDS-PAGE电泳和Western blot检测其表达情况和免疫原性。结果显示,扩增的σC基因序列与Gen Bank所发表的序列同源性为100%;σC重组蛋白能在大肠杆菌中大量表达,其分子量约为30 kDa,且能被MDRV阳性血清识别,具有良好的抗原结合活性。σC重组蛋白的成功表达,将对后续围绕该蛋白的功能鉴定、诊断用抗原制备或新型疫苗研制工作有所帮助。     

CFSE标记法分析番鸭呼肠孤病毒感染对番鸭回肠淋巴细胞归巢的影响

旨在建立一种可靠的体外活番鸭淋巴细胞的荧光标记方法,并用于分析番鸭呼肠孤病毒感染对雏番鸭回肠淋巴细胞归巢的影响。选择活细胞荧光染剂5（6）-羧基二乙酸荧光素琥珀酰亚胺酯（CFDA-SE,CFSE）对分离的番鸭淋巴细胞进行标记和利用流式细胞术对体外标记的淋巴细胞体内示踪检测分析,并利用该方法对MDRV感染雏番鸭回肠组织的淋巴细胞数量进行流式细胞术和石蜡切片免疫荧光检测分析;结果最终确定CFSE体外标记番鸭淋巴细胞的条件为以PBS为孵育液,终浓度10 μmol·L^-1,37℃ 30 min;试验结果表明番鸭外周血内的CFSE⁺淋巴细胞率基本稳定在2%~5%,CFSE⁺淋巴细胞峰值出现顺序依次为脾、空肠、回肠、盲肠、十二指肠、法氏囊和胸腺;此外,感染MDRV后1~10 d MDRV组中CFSE⁺淋巴细胞率极显著（P<0.01）高于MOCK组,该结果与α4⁺淋巴细胞率和石蜡切片免疫荧光检测结果一致。结果表明本试验CFSE标记的淋巴细胞可用于体内淋巴细胞示踪,初步应用结果提示MDRV感染促进番鸭淋巴细胞向回肠归巢,为进一步阐明MDRV感染的肠道组织致病机制奠定了基础。     

番鸭呼肠病毒病的病原学研究进展

番鸭呼肠病毒病是由番鸭呼肠病毒引起的一种急性传染病,主要发生于40日龄内的番鸭,临床上以软脚为主要症状,并伴有腹泻,发病率高,病情严重时可致全群死亡,给番鸭养殖业带来了巨大的损失。其病原为呼肠病毒科正呼肠病毒属番鸭呼肠病毒。文章综合了国内外对该病的病原学研究成果,从病毒的分类地位、生物学特性、基因组与编码蛋白、病原分布及流行特性、检测与防控等方面对该病的病原学进行了较全面的论述,以期对该病的深入研究和防控提供有用的资料。     

猴头菇多糖对呼肠孤病毒感染番鸭组织病变及细胞凋亡的影响

为探讨猴头菇多糖对呼肠孤病毒感染雏番鸭组织病变及细胞凋亡的影响。本实验通过建立呼肠孤病毒感染的肝脾组织病变的动物模型,应用猴头菇多糖对感染番鸭进行防治,给药组分别添加0.01%,0.02%,0.03%的猴头菇多糖,观察其对肝脾组织病变及其细胞凋亡的影响。实验结果发现给药组的番鸭发病时间延迟、死亡率下降,细胞病变坏死较少,用中剂量的猴头菇多糖的治疗呼肠孤病毒病效果最明显。实验数据还表明猴头菇多糖给药组在病毒感染的早期促进细胞凋亡,晚期抑制细胞凋亡,这可能是猴头菇多糖能对呼肠孤病毒感染产生积极影响的原因,它有助于防止病毒在细胞中的扩散甚至有利于病毒的清除。此项研究为国内首次报道。     

Detection and differentiation of avian reoviruses using SYBR-Green I-based two-step real-time reverse transcription PCR with melting curve analysis

A two-step SYBR-Green I-based real-time PCR with melting curve analysis was developed to detect and differentiate the avian reovirus (ARV) sigmaC gene in field and vaccine ARVs. Three primer sets were used to amplify the sigmaC gene from its 5', center, and 3' regions and analyze the melting point temperatures of nine ARVs. By combining the melting curves of the three ARV sigmaC gene regions, melting curve analysis could accurately distinguish the ARVs of different subtypes, and the results were consistent with phylogenetic analysis. The ARV sigmaC gene polymorphisms from different strains were also used to explain the differences in melting point temperatures. Compared with traditional subtyping methods, the current melting curve analysis provided an accurate test for separating ARVs, thereby making it a useful method for the improved selection of ARV vaccines.     

Muscovy duck reovirus infection rapidly activates host innate immune signaling and induces an effective antiviral immune response involving critical interferons

Muscovy duck reovirus (MDRV) is a highly pathogenic virus in waterfowl and causes significant economic loss in the poultry industry worldwide. Because the host innate immunity plays a key role in defending against virus invasion, more and more attentions have been paid to the immune response triggered by viral infection. Here we found that the genomic RNA of MDRV was able to rapidly induce the production of interferons (IFNs) in host. Mechanistically, MDRV infection induced robust expression of IFNs in host mainly through RIG-I, MDA5 and TLR3-dependent signaling pathways. In addition, we observed that silencing VISA expression in 293T cells could significantly inhibit the secretion of IFNs. Remarkably, the production of IFNs was reduced by inhibiting the activation of NF-κB or knocking down the expression of IRF-7. Furthermore, our study showed that treatment of 293T cells and Muscovy duck embryo fibroblasts with IFNs markedly impaired MDRV replication, suggesting that these IFNs play an important role in antiviral response during the MDRV infection. Importantly, we also detected the induced expression of RIG-I, MDA5, TLR3 and type I IFN in Muscovy ducks infected with MDRV at different time points post infection. The results from in vivo studies were consistent with those in 293T cells infected with MDRV. Taken together, our findings reveal that the host can resist MDRV invasion by activating innate immune response involving RIG-I, MDA5 and TLR3-dependent signaling pathways that govern IFN production.     

不同毒力番鸭呼肠孤病毒在番鸭免疫器官的分布和排毒

探讨番鸭呼肠孤病毒强毒株和弱毒株在番鸭免疫器官中的分布和排毒的差异。结果显示强毒株在感染后1d就可在脾脏、法氏囊、胸腺检出病毒RNA,高峰期为攻毒后7～14d;直到感染后35d,在免疫器官中不能检测到病毒RNA。接种强毒株后7d开始向外界排毒,而14d后停止向外界排毒。雏鸭免疫弱毒疫苗后3d,即可在脾、胸腺、法氏囊中检出病毒RNA;高峰期为攻毒后7～14d,免疫后21d免疫器官中的检测逐渐降低,直到感染后28d,在免疫器官中不能检测到病毒RNA。表明番鸭接种活疫苗后7d开始向外界排毒,而11d后停止向外界排毒。     

新型鸭呼肠孤病毒QY株σB蛋白基因特征、二级结构预测及其细胞抗原表位分析

本研究旨在对新型鸭呼肠孤病毒（NDRV）QY株σB蛋白的遗传变异规律和结构及功能进行分析。从GenBank数据库中获取QY株和25株参考株的σB蛋白编码序列,通过Mega 6.0软件进行序列比对分析和系统进化树构建;使用Datamonkey软件进行选择压力分析;运用生物信息学软件预测QY株σB蛋白二级结构功能及B细胞和T细胞抗原表位。相似性分析结果显示,NDRV QY株与国内其他地区分离的鸭呼肠孤病毒（DRV）氨基酸相似性达到94.9%~98.9%,与禽呼肠孤病毒（ARV）及番鸭呼肠孤病毒（MDRV）的相似性仅为66.5%~68.4%和67.6%~68.4%;选择压力分析显示,σB蛋白承受净化选择压力,但存在一个正向选择位点;σB蛋白属于亲水蛋白,不具有信号肽和跨膜区,含有潜在的O-糖基化位点;结构预测分析显示,σB蛋白具有α-螺旋、β-折叠、β-转角及无规则卷曲等丰富的二级结构;表位分析显示,σB蛋白含有潜在的B细胞和T细胞抗原表位。本研究成功进行了QY株σB蛋白的基因特征和结构功能预测及其细胞表位分析,为深入了解该蛋白的免疫学特性及研发NDRV新型疫苗奠定了基础。     

广东新型鸭呼肠孤病毒σB蛋白基因克隆及序列分析

为研究广东新型呼肠孤病毒（NDRV）的基因变异及遗传演化情况,本试验从广东不同鸭场病死鸭肝脏、脾脏等组织脏器中分离到8株流行毒株,用RT-PCR方法进行σB蛋白基因扩增、克隆与序列分析,并与其他毒株σB蛋白的氨基酸特性、蛋白抗原和蛋白基因进行系统进化比对分析。结果表明,广东省鸭群中感染的NDRV与国内其他地区报道的DRV核苷酸序列同源性很高,达96.6%~99.5%,而与禽呼肠孤病毒（ARV）和番鸭呼肠孤病毒（MDRV）的同源性则较低,分别为64.6%~66.5%和66.2%~67.1%;8株NDRV之间的核苷酸序列同源性高达97.7%~99.7%。与其他毒株比较结果显示,本试验分离的NDRV毒株磷酸化位点均比参考毒株ARV和MDRV少,且大多数区域的抗原指数都较高,抗原性与MDRV较为接近,遗传进化分析结果表明,NDRV和国内其他DRV处于独立的进化分支,ARV和MDRV则处于不同分支。结果表明,广东省流行的NDRV毒株σB蛋白基因序列高度保守,且广东地区分离的NDRV与国内其他地区分离的DRV没有明显的地域差异。     

Isolation and characterization of a reovirus from common eiders (Somateria mollissima) from Finland

Samples of brain, intestine, liver, lung, spleen, and bursa of Fabricius were collected from five common eider (Somateria mollissima) duckling carcasses during a die-off in the western Gulf of Finland (59 degrees 50'N, 23 degrees 15'E) in June 1996. No viral activity was observed in specific-pathogen-free chicken embryos inoculated with tissue suspensions, but samples of bursa of Fabricius from three birds were positive when inoculated into Muscovy duck (Cairina moschata) embryo fibroblasts. The isolates were characterized as nonenveloped RNA viruses and possessed several characteristics of the genus Orthoreovirus. Virus particles were icosahedral with a mean diameter of 72 nm and were stable at pH 3.0; their genome was separated into 10 segments by polyacrylamide gel electrophoresis. Mallard (Anas platyrhynchos) ducklings experimentally infected with the eider reovirus showed elevated serum activities of aspartate aminotransferase, creatine kinase, and lactate dehydrogenase enzymes and focal hemorrhages in the liver, spleen, and bursa of Fabricius. During 1997-99, the prevalence of neutralizing antibodies to the isolated virus ranged from 0 to 86% in 302 serum samples collected from incubating eider hens at three nesting areas along coastal Finland. The highest seroprevalence was found in Hanko in 1999, just weeks before reports of an uninvestigated mortality event resulting in the death of an estimated 98% of ducklings at that location. These findings raise the question of potential involvement of the virus in poor duckling survival and eider population declines observed in several breeding areas along coastal Finland since the mid-1980s.     

Isolation and Molecular Characterization of Fowl Adenovirus and Avian Reovirus from Breeder Chickens in Japan in 2019–2021

Fowl adenoviruses (FAdVs) and avian reoviruses (ARVs) are ubiquitous in poultry farms and most of them are not pathogenic, yet often cause damage to chicks. A total of 104 chicken fecal samples were collected from 7 farms of breeder chickens (layers and broilers) in Japan from 2019 to 2021, and yielded 26 FAdV plus 14 ARV isolates. By sequencing, FAdV isolates were classified as FAdV-1, 5 and 8b. ARV isolates were classified as genotype II, IV and V. These results suggest that FAdVs and ARVs are resident in the breeder chicken farms in Japan.