鱼类病毒性神经坏死病毒衣壳蛋白在昆虫细胞中的表达及其特性

利用RT-PCR技术获得病毒性神经坏死病毒0603株的衣壳蛋白基因,将其插入到杆状病毒Bac-To-Bac表达系统的pFastBacI质粒中,构建了pFastBac-cp质粒.转化DH10Bac大肠杆菌后获得重组穿梭载体Bacmid-cp,脂质体介导将其转染Sf9细胞产生有感染性的重组杆状病毒AcNPV-cp.利用AcNPV-cp感染Sf9细胞后,SDS-PAGE分析可见大小约为37 ku的特异性蛋白带,Western-blotting分析发现,其可以与病毒性神经坏死病毒阳性血清反应出现特异性的杂交带.试验结果表明,AcNPV-cp在Sf9细胞中成功地表达了病毒性神经坏死病毒的衣壳蛋白,其具有良好的免疫学活性.负染电镜观察发现,CP蛋白可自行装配成病毒样颗粒,其大小形态类似于病毒性神经坏死病毒.制备超薄切片后电镜观察发现,CP蛋白自行装配成的病毒样颗粒呈晶格状排列在细胞质中.为研制有效防控鱼类病毒性神经坏死病的新型颗粒性疫苗奠定了基础.     

中科院水生所关于水生病毒学研究取得进展

<正>蛙病毒(Ranavirus)是一类能跨种感染全球各地变温动物(包括鱼类、两栖类、爬行类等)的核质大DNA病毒(NCLDVs)成员,但其复制和转录机制在较大程度上仍属未知。近日,中国科学院水生生物研究所水生病毒学学科组基于建立高效蛙病毒重组、基因复制及功能测试系统,以及从鱼类细胞新生DNA中分离特定蛋白、重组病毒亲和层析和纳米荧光素酶Nano Luc互补及质谱分析技术,鉴定并揭示了蛙病毒复制和转录机器的组织架构及相关作用机制。     

虹鳟传染性造血器官坏死病-传染性胰腺坏死病重组腺病毒载体的构建

传染性造血器官坏死病和传染性胰腺坏死病是以感染鲑科鱼类为主的两种传染病。为克隆传染性造血器官坏死病病毒IHNVG基因和传染性胰腺坏死病病毒IPNVVP2基因,并构建其重组腺病毒载体。利用RT-PCR方法分别扩增出IHNVG基因和IPNVVP2基因,通过多基因片段同源重组技术将IHNVG基因和IPNVVP2基因克隆到pAdTrack-CMV载体上,经过线性化后与pAdEasy-1载体在BJ5183菌体内同源重组,构建出重组腺病毒质粒,经PCR及NotⅠ和HindⅢ双酶切鉴定后,再经PacⅠ线性化后用于转染HEK-293细胞,获得重组腺病毒。通过绿色荧光蛋白(green fluorescent protein, GFP)的表达来监控重组腺病毒的复制情况,用western blot法分别检测糖蛋白(G蛋白)和VP2蛋白的表达,并测定重组病毒的滴度。结果显示,克隆出的IHNVG基因和IPNVVP2基因总长度为3 036 bp。该病毒在HEK-293细胞中分别表达出蛋白分子质量约为58 kD和54 kD的产物,其滴度为1.0×10^9.5 mL^-1 TC...     

白斑综合征病毒囊膜蛋白vp28基因在毕赤酵母中的表达

白斑综合征病毒(whitespotsyndromevirus,WSSV)是危害东南亚及北美洲沿岸养殖对虾的重要病原。近十年来,国内外对该病毒的形态结构、基因组全序列、宿主范围、传播途径、致病性和组织细胞特异性等作了大量的研究[1-7],并已确定该病毒的侵染与其囊膜蛋白vp28有关[8]。实验根据已发表的白斑综合征病毒囊膜蛋白vp28基因序列[9]设计一对引物,通过PCR扩增出该囊膜蛋白的基因片段。将该片段连接到毕赤酵母表达载体pPICZ上,在大肠杆菌中筛选到含目的基因的重组质粒pPICZVP28,用电穿孔法将重组质粒转化到毕赤酵母菌株X33中,获得了转化子X33 …     

鱼类神经坏死病病毒衣壳蛋白在昆虫细胞中的表达及其特性

鱼类病毒性神经坏死病毒能引起多种海水鱼类中枢神经组织病变,给各国海水养殖业造成了巨大的损失。本研究利用RT-PCR技术获得病毒性神经坏死病毒0603株的衣壳蛋白基因,将其插入到杆状病毒Bac-To-Bac表达系统的pFastBacⅠ质粒中,构建了pFastBac-cp质粒。转化DH10Bac大肠杆菌后获得重组穿梭载体Bacmid-cp,脂质体介导将其转染Sf9细胞产生有感染性的重组杆状病毒AcNPV-cp。利用AcNPV-cp感染Sf9细胞后,SDS-PAGE分析可见大小约为37kD的特异性蛋白带, Western-blotting分析发现,其可以与病毒性神经坏死病毒阳性血清反应出现特异性的杂交带,试验结果表明AcNPV-cp在Sf9细胞中成功地表达了病毒性神经坏死病毒的衣壳蛋白,其具有良好的免疫学活性。负染电镜观察发现,CP蛋白可自行装配成病毒样颗粒,其大小形态类似于病毒性神经坏死病毒。制备超薄切片后电镜观察发现,CP蛋白自行装配成的病毒样颗粒呈晶格状排列在细胞质中。 本研究为研制有效防控鱼类病毒性神经坏死病的新型颗粒性疫苗奠定了基础。     

鳗鲡疱疹病毒的分离与鉴定

为获知鳗鲡"脱粘败血病"与病毒的关系,实验用蔗糖密度梯度离心的方法从发病的欧洲鳗鲡内脏器官组织匀浆液中纯化了病毒粒子,负染后利用电镜观察;进一步用EO细胞对病毒进行了分离、培养,并对感染病毒的细胞进行超薄切片,电镜观察;然后,提取病毒DNA,利用鳗鲡疱疹病毒的PCR检测方法对其进行了鉴定。结果显示,接种匀浆上清液的EO细胞出现细胞融合的病变效应;分离病毒的病毒粒子具囊膜,大小约为200 nm;从感染病毒的细胞上清液DNA中扩增出特异性条带,序列测定与比对分析表明,该序列与鳗鲡疱疹病毒欧洲株(AngHV-1)的序列完全一致。研究表明,利用EO细胞分离了一株鳗鲡病毒,经形态观察和DNA分析,确认该病毒为鳗鲡疱疹病毒,命名为AngHV-FJ。该研究为深入开展鳗鲡疱疹病毒的致病机制及鳗鲡"脱粘败血病"的防控研究奠定了重要基础。     

斑节对虾细胞周期蛋白B慢病毒载体的构建及对Hela细胞增殖影响

细胞周期蛋白B（Cyclin B）是影响卵母细胞发育成熟的重要基因。文章构建了PmCyB慢病毒表达载体,并和慢病毒包装复合物在293T细胞中包装成慢病毒颗粒。利用包装好的慢病毒颗粒,感染干扰了Cyclin B1基因的Hela细胞,研究了PmCyB对Hela细胞增殖的影响。结果表明,通过siRNA干扰细胞自身的Cyclin B1后,转染对照组病毒液的Hela细胞增殖减缓;同时,干扰后转入含有PmCyB重组慢病毒表达载体,Hela细胞增殖速度明显要高于转染对照组病毒液的Hela细胞的增殖速度。这一结果表明,PmCyB基因的过表达能补偿Cyclin B1缺失导致的细胞增殖减缓的现象,说明PmCyB基因具有细胞周期调控功能,是细胞增殖与分化的重要调控基因,且功能可能与人类的Cyclin B1相似。人类的Cyclin B1是卵母细胞发育成熟的重要基因。由此可以推断,PmCyB基因可能对斑节对虾（Penaeus monodon）卵巢发育成熟起着重要作用。     

鲤疱疹病毒3型ORF148 DNA疫苗对建鲤鱼苗的免疫保护

鲤疱疹病毒3型(Cyprinid herpesvirus 3, CyHV-3)又称为锦鲤疱疹病毒(Koi herpesvirus, KHV),是一种高传染性、致死性病毒。为开发新型CyHV-3 DNA疫苗,前期研究中将CyHV-3 ORF148基因插入pEGFP-N1构建重组质粒,在此基础上,本研究通过转染试验、间接免疫荧光试验证实pORF148-EGFP融合蛋白可以在CCB-J细胞系和建鲤体内表达;将重组质粒作为DNA疫苗,肌肉注射免疫建鲤鱼苗,ELISA检测表明免疫pEGFP-ORF148重组质粒可以显著提高建鲤血清特异性抗体水平; RT-qPCR检测显示,免疫pEGFP-ORF148重组质粒后,建鲤脾脏和头肾中的免疫相关基因如IFN-a1、Mx-1、CXCa、CXCR1、TNF-α、IL-1β及IgM基因表达量均显著提高。攻毒实验显示, CyHV-3攻毒21 d后, PBS组、pEGFP-N1组和pEGFP-ORF148组的建鲤存活率分别为30%、35%和85%,免疫pEGFP-ORF148可以显著提高建鲤的存活率(P0.01)。本研究旨在为CyHV-3 DNA疫苗的应用提供理论依据。     

斑点叉尾鮰病毒“自杀性”DNA疫苗的构建及其体外表达检测

根据CCVORF6基因序列,设计合适的引物,扩增ORF6基因,分别将其克隆到自杀性DNA疫苗载体pS-FV与常规DNA疫苗载体pcDNA3.1(+)中,转化感受态细胞DH5α后提取质粒,构建斑点叉尾鮰(Ictalurus punc-tatus)自杀性DNA疫苗ps-ORF6与常规DNA疫苗pcd-ORF6,利用转化后的大肠杆菌菌液为模板进行PCR扩增、提取质粒酶切鉴定以及序列测定等方法证实重组质粒构建正确。将重组质粒转染人胚肾细胞(293T),间接免疫荧光试验表明ORF6均获得表达,但自杀性DNA疫苗的表达效果不如常规DNA疫苗,该研究为这2种疫苗进一步的鱼体试验奠定了基础。     

草鱼呼肠孤病毒NS79蛋白多克隆抗体制备

草鱼呼肠孤病毒(Grass carp reovirus,GCRV)隶属于呼肠孤病毒科,水生呼肠孤病毒属,该病毒引起草鱼鱼种出现严重的出血病。GCRV基因组由11个分节段的双链RNA构成,NS79是由草鱼呼肠孤病毒GCRV-HN14株S4节段编码的蛋白。根据草鱼呼肠孤病毒编码NS79的c DNA序列,经PCR扩增NS79基因部分片段,将目的基因片段插入原核表达载体p ET-32a(+),构建重组表达质粒NS79E-p ET-32a,转化到大肠杆菌BL21(DE3)中,IPTG诱导表达,表达出来融合蛋白分子量约为35k Da,表达的重组蛋白用Ni-IDASefinose(TM)树脂纯化后免疫新西兰大白兔,制备多克隆抗体,采用ELISA法测定其效价大于1:64000。这些结果为NS79蛋白功能的深入研究提供基础。     

Recombinant channel catfish virus (Ictalurid herpesvirus 1) can express foreign genes and induce antibody production against the gene product

The potential use of channel catfish virus (CCV) (Ictalurid herpesvirus 1) as a vaccine vector for the channel catfish industry was investigated by inserting the Escherichia coli lacZ gene into the CCV genome and evaluating the immune response to the foreign gene product in catfish exposed to the recombinant. The recombinant virus was produced by inserting the lacZ in reading frame with the ATG start codon of the CCV thymidine kinase (TK) gene in the recombinant transfer plasmid pBSCV457 described previously. The plasmid was then cotransfected with CCV DNA in a TK gene-mediated selectable homologous recombination. The recombinant progeny were selected by resistance to 0.1 mM acycloguanosine (acyclovir) and the production of blue plaques in the presence of 5-bromo-4-chloro-3-indolyl-β-D-galactopyranoside (X-gal). The resultant construct (CCVlacZ) was TK^?, and contained the lacZ gene at both TK loci in the genome. β-Galactosidase expression in infected CCO ceils reached 0.53 μg per 10⁶ CCO cells at 12 h post-infection. When channel catfish fingerlings were immersion exposed to CCVlacZ, these developed an antibody response to the inserted foreign gene product which peaked at approximately 15–20 days post-infection. Additionally, the anti-β-galactosidase response was significantly enhanced when the fingerlings were re-exposed to the virus 20 days after the initial exposure. These results demonstrate that foreign genes can be inserted into and expressed by CCV and that such constructs could be used as vaccine vectors.     

尼罗罗非鱼(Oreochromis niloticus) cyp19a1a原核表达与蛋白纯化

为表达和纯化尼罗罗非鱼(Oreochromis niloticus)cyp19a1a蛋白,本研究从尼罗罗非鱼卵巢提取总RNA,反转录获得cDNA模板后,利用设计的引物PCR扩增cyp19a1a ORF区1200 bp片段,双酶切后连接到pET-28a(+)表达载体上,经酶切验证和DNA测序鉴定,证明成功构建了pET-28a-cyp19a1a原核表达载体。将表达载体转化到大肠杆菌(E.coli)BL21中,优化IPTG诱导浓度和诱导时间。结果显示,在0.5 mmol/L IPTG诱导8 h后,cyp19a1a重组蛋白大量表达,并以包涵体形式存在。通过Ni2+-NTA层析柱和切胶纯化,获得与预期片段大小一致的表达蛋白,并用Western blotting验证了纯化的蛋白为目的蛋白。本研究为制备cyp19a1a抗体和研究高温对cyp19a1a蛋白表达的影响提供了重要的基础。     

Construction and expression of DNA vaccine against reddish body iridovirus and evaluation of immune efficacy in turbot (Scophthalmus maximus)

Turbot aquaculture is a very important industry in China. However, it is hampered because of viral reddish body syndrome (VRBS) and high mortality caused by piscine turbot reddish body iridovirus (TRBIV). TRBIV virus is an icosahedron‐like and cytoplasmic DNA virus, belonging to Iridoviridae, Megalocytivirus. In previous studies, we have identified two antigen mimotopes using bioinformatics and constructed prokaryotic expression vectors. In this study, a fragment of major capsid protein (MCP) gene with the two antigenic epitopes was cloned into eukaryotic expression vector pVAX1, to generate a recombinant plasmid pVAX1‐TRBIV‐MCP. The plasmid DNA was transferred into turbot cell line TK using liposome, and transient expression was detected using RT‐PCR. After injection into turbot (Scophthalmus maximus), the expression of the antigen gene was analysed using RT‐PCR and was shown to express in all tested tissues in vaccinated fish 2 and 7 days post‐vaccination. The cumulative mortalities in the vaccinated and unvaccinated control fish were 30% and 88% respectively. Immune responses and upregulation of the expression of chemokine receptor, tumour necrosis factor, interferon and interferon‐induced antiviral molecules were observed in the vaccinated fish 60 h post‐vaccination. These results demonstrate that the vaccinated turbots had higher survival rate and produced specific serum antibodies following the TRBIV challenge. More studies are needed to develop and apply the promising DNA vaccine for virus control in turbot.     

急性病毒性坏死病毒dUTPase基因的克隆、表达及其产物的酶学活性分析

根据已测定完成的栉孔扇贝急性病毒性坏死病毒(acute viral necrosis virus,AVNV)基因组序列,设计特异性引物,以提取的发病扇贝组织总DNA为模板,PCR扩增得到编码AVNV dUTPase的开放阅读框ORF074,将产物克隆至原核表达载体pET32a(+)中,构建表达质粒pET32a-dut。然后,将其转化至E.coli BL21(DE3)进行诱导表达。SDS-PAGE检测显示,诱导表达蛋白分子量约为46 ku,与预期表达蛋白大小一致。经Western-blotting及质谱分析鉴定,所表达蛋白即为重组dUTPase。表达产物经Co²⁺柱纯化后进行酶学活性测定。结果显示,重组dUTPase能特异性催化dUTP,EDTA可以抑制dUTPase的活性,而Mg²⁺可以增强其活性。     

胭脂鱼细胞色素b基因序列测定及亚口鱼科系统进化分析

为了解胭脂鱼(Myxocyprinus asiaticus)的遗传变异及亚口鱼(Catostomidae fish)的分子系统学,测定了3尾胭脂鱼的细胞色素b基因序列,并结合GenBank上5条亚口鱼科鱼类的相应序列一并分析。结果如下:1)共获得3尾胭脂鱼的细胞色素b基因1144 bp的一致序列,三条序列完全相同,无变异位点。2)构建的系统发育树显示,颈棱亚口鱼属(Xyrauchen texanus)和吸口鱼属(Moxostoma robustum)构成1支,胭脂鱼属(M yxocyprinus)、长背亚口鱼属(Cycleptus elongatus)和牛胭脂鱼属(Ictiobus)构成另1分支。3)自然选择检验显示,该基因在进化过程中主要受到负选择的作用。4)胭脂鱼属和牛胭脂鱼属的分歧时间最短(大约3.725百万年),颈棱亚口鱼属和长背亚口鱼属的分歧时间最长(大约5.375百万年)。     

盐藻钙依赖蛋白激酶基因DsCDPK的表达分析

以盐藻总RNA为模板,利用RT-PCR技术扩增了盐藻DsCDPK基因的cDNA序列,将其克隆到pMD^TM19-T simple载体上,经测序获得的克隆片段全长1650 bp,与已发表的盐藻DsCDPK(GenBank:JQ964113)的编码区序列同源性达100%。将DsCDPK基因的开放阅读框与质粒pET-32a(+)连接,构建原核表达载体pET-32a-DsCDPK。将该重组质粒转化到大肠杆菌BL21中,经IPTG诱导融合,蛋白在大肠杆菌BL21中得到成功表达。通过SDS-PAGE检测发现,融合蛋白为部分可溶性表达,将上清蛋白经过His柱纯化后获得了纯度较高的可溶性融合蛋白,Western杂交检测显示,融合蛋白能被抗His单克隆抗体特异性识别,初步证明该融合蛋白就是带有His标签的DsCDPK蛋白。采用实时荧光定量PCR方法分析了高盐胁迫下DsCDPK基因的表达模式。试验结果表明,盐藻DsCDPK基因为盐胁迫上调基因,在高盐(3.0 mol/L NaCl)胁迫下,DsCDPK基因表达量显著增加,盐胁迫1 h时表达量达到最高,为正常生长状况(1.0 mol/L NaCl)下的3倍,差异达到极显著水平(P<0.01)。该研究成果为进一步阐明盐藻钙依赖蛋白激酶基因的功能及作用机制奠定了基础。     

Virulence of a chimeric recombinant infectious haematopoietic necrosis virus expressing the spring viraemia of carp virus glycoprotein in salmonid and cyprinid fish

Infectious haematopoietic necrosis virus (IHNV) and spring viraemia of carp virus (SVCV) are both rhabdoviruses of fish, listed as notifiable disease agents by the World Organization for Animal Health. Recombinant rhabdoviruses with heterologous gene substitutions have been engineered to study genetic determinants and assess the potential of these recombinant viruses for vaccine development. A recombinant IHNV (rIHNV), containing the full‐length genome of a European IHNV strain, was modified by deleting the glycoprotein (G) gene and replacing it with a European SVCV G‐gene to make the rIHNV‐Gsvcv. The chimeric rIHNV‐Gsvcv level of virulence in rainbow trout, common carp and koi was assessed, and its ability to induce a protective immune response in surviving koi against wild‐type SVCV infection was tested. The rIHNV‐Gsvcv infection of trout led to high mortality, ranging from 78% to 92.5%, after immersion. In contrast, no deaths occurred in juvenile common carp after infection with rIHNV‐Gsvcv by either immersion or intraperitoneal (IP) injection. Similarly, koi infected with rIHNV‐Gsvcv via IP injection had little to no mortality (≤9%). Koi that survived initial infection with a high dose of recombinant virus rIHNV‐Gsvcv were protected against a virulent SVCV challenge resulting in a high relative per cent survival of 82.5%.     

转生长激素基因中华倒刺鲃的构建及其检测

用从斑点叉尾鮰(Ictalurus punctatus)cDNA文库克隆到的生长激素基因,与鲤β肌蛋白启动子、大麻哈鱼生长激素基因的poly(A)终止信号序列等调控元件共同构建了表达重组质粒pFV2 cfGH。提取重组质粒,用精子载体法导入中华倒刺鲃(Spinibarbus sinensis)的受精卵中,经孵化培养成转基因成鱼。抽提423尾转基因实验鱼血总DNA,经PCR检测表明:斑点叉尾鮰生长激素基因已导入中华倒刺鲃基因组中,导入率为17.26%。同时通过RT-PCR技术检测阳性中华倒刺鲃中生长激素基因的表达情况。     

Development of immunodot blot assay for the detection of white spot syndrome virus infection in shrimps (Penaeus monodon)

The VP 28 gene encoding a structural envelope protein of the white spot syndrome virus (WSSV) was cloned into a pET32a(+) expression vector for the production of the recombinant VP28 protein. A purified recombinant protein of 39.9 kDa size was used for polyclonal antibody production in rabbit. Specific immunoreactivity of the rabbit anti rVP28 antiserum to the viral antigen was confirmed by a Western blot. The specificity of this polyclonal anti‐rVP28 antiserum to detect the presence of the virus in WSSV‐infected Penaeus monodon was verified using a immunodot blot assay. Immunodot blot showed a positive reaction in infected shrimp tissues with prominent colour development using 3,3′,5,5′‐tetramethylbenzidine (TMB) as a chromogenic substrate when compared with 3–3′ diaminobenzidine tetrahydrochloride (DAB). Highest signal intensities of the immunodots were observed in infected shrimp pleopod extracts and haemolymph. On comparison with polymerase chain reaction (PCR), immunodot blot could detect 76% of PCR‐positive WSSV‐infected shrimp samples. Immunodot blot was found to be equivalent to first‐step PCR sensitivity to detect WSSV particles estimated to contain 1.0 × 10⁵ viral DNA copies.