狂犬病病毒糖蛋白原核表达及纯化

试验旨在提高狂犬病病毒(rabies virus,RV)糖蛋白(G)在大肠杆菌(E.coli)BL21(DE3)中的表达量。通过优化蛋白质诱导表达的温度、时间、诱导剂浓度等条件,以提高该蛋白质的表达量。SDS-PAGE电泳分析结果显示,重组质粒在1 mmol/mL IPTG、30 ℃诱导6 h条件下蛋白表达量最高,经GST-resin亲和层析柱法纯化获得的纯化蛋白约为36 ku,与预期大小相符。Western blotting结果显示,表达蛋白具有很好的免疫原性和特异性。结果表明,RV G融合蛋白的优化表达和纯化为RV亚单位疫苗及中和抗体的研制奠定了基础。     

3拷贝鸡胸腺素α1基因在大肠杆菌中的融合表达及活性分析

为表达鸡胸腺素α1(Thymosin alpha 1,Tα 1),并对其进行纯化及生物学活性分析,本研究根据大肠杆菌基因密码子偏嗜性对Tα 1基因进行优化,人工合成了Tα1三拷贝融合基因.并将其克隆至原核表达载体pET-30a中,转化至BL21(DE3)菌株,经IPTG诱导表达和镍柱纯化,获得融合蛋白.融合蛋白经羟胺切...     

鲤春病毒(SVCV)糖蛋白基因的原核表达

通过将鲤春病毒血症病毒(Spring Viremia of Carp Virus,SVCV)糖蛋白(Glycoprotein,G)基因截短后构建重组表达载体,实现体外高效表达G蛋白,为有关原核诱导蛋白提供参考。以质粒pEGFP-G为模板设计引物,分别扩增G基因的不同片段,与密码子优化后的G基因分别插入pET-32a表达载体,构建重组表达载体pET-32a-GX和pET-32a-OG。经过鉴定后,将重组质粒分别转入大肠杆菌BL21(DE3),通过适宜条件的诱导表达,获得诱导产物并进行SDS-PAGE和Western blotting检测。构建了重组表达载体pET-32a-GX与含密码子优化后G基因的重组表达载体pET-32a-OG;经适宜条件诱导表达了G蛋白后的SDS-PAGE和Western Blotting检测,表明G蛋白成功表达,且含截短片段的重组载体pET-32a-G2的蛋白表达量最高,与原G序列有相同的免疫原性。成功构建截短后的原核表达载体pET-32aGX与密码子优化后的重组表达载体pET-32a-GX,并实现体外大量诱导SVCV的G蛋白。     

家蚕G蛋白γ1亚基(BmGγ1)的克隆及其谷胱甘肽硫转移酶融合蛋白的表达与纯化

异三元G蛋白是真核细胞感知外界信号后将信号传递到胞内的重要分子,参与生物体广泛的信号转导。为了研究家蚕体内G蛋白的生理功能及其作用机制,运用生物信息学方法预测了家蚕G蛋白γ1亚基(Gγ1)的序列,设计引物验证预测序列后,克隆了家蚕Gγ1的序列,再通过酶切克隆至表达载体pET-41b(+)后,导入E.coliBL21宿主菌中,经异丙基β-D-硫代半乳糖苷(IPTG)诱导表达重组谷胱甘肽硫转移酶(glutathione s-transferase,GST)融合蛋白,并亲和层析纯化表达产物。家蚕Gγ1重组GST融合蛋白经SDS-PAGE电泳和Western blot分析,在分子质量约36 kD处出现特异性蛋白条带,重组蛋白经GST亲和层析柱纯化后,得到了高纯度的融合蛋白,说明已经成功克隆到家蚕Gγ1基因,并在E.coliBL21中高效表达。     

伪狂犬病病毒Bartha株gC膜外区部分基因的原核表达及纯化

构建伪狂犬病病毒(PRV)gC膜外区部分基因的重组质粒,原核表达并纯化目的蛋白.根据GenBank已发表的伪狂犬病病毒Bartha(PRV Ba)株gC基因的序列(NC EU719641),设计并合成了1对引物,以PRV Ba株为模板,PCR扩增出PRV gC膜外区部分基因片段;将该基因片段克隆到原核表达载体pET-28a上,转化大肠埃希菌BL21(DE3),经IPTG诱导,获得大小为35 ku的重组蛋白,命名为pET-gCN813.按照His-Bind纯化试剂盒说明书纯化表达产物,获得融合蛋白的纯化产物.     

水泡性口炎病毒糖蛋白主要抗原决定区片段基因的原核表达和纯化

参照GenBank中水泡性口炎病毒(Vesicular stomatitis virus,VSV)G蛋白基因的核苷酸序列,设计合成1对特异性引物,采用RT-PCR方法扩增约为810bp的G基因片段,并将其克隆到pGEX-4T-1表达载体上,将经PCR、酶切鉴定以及测序分析正确的阳性重组质粒命名为PGEX-G810,之后将其转化至表达菌株E.coli BL21(DE3),经IPTG进行诱导表达;表达产物经SDS-PAGE、Western blotting等方法进行检测。SDS-PAGE结果表明,重组蛋白主要以包涵体形式存在,相对分子质量约为60 000;包涵体经变性、复性、Glutathione Sepharose 4B亲和层析纯化后,分离得到复性的融合蛋白。纯化的融合蛋白能与VSV阳性血清发生特异性免疫反应,证明表达的目的蛋白具有良好的抗原性。     

鸭坦布苏病毒E基因主要抗原域的原核表达及单克隆抗体的制备

为制备鸭坦布苏病毒(DTMUV)E基因主要抗原域的单克隆抗体(MAb),本研究经DNAStar软件分析预测E蛋白含有的优势抗原表位区,以DTMUV QD株基因组RNA为模板,通过RT-PCR扩增涵盖编码主要优势表位的E基因片段(943 bp~1 287 bp),并将其克隆至表达载体p ET-28a中,转化于大肠杆菌中进行诱导表达。对表达的重组蛋白进行western blot鉴定,将纯化后的重组蛋白免疫BALB/c小鼠,取其脾脏细胞与SP2/0细胞融合,经筛选和鉴定,获得了两株能够稳定分泌抗E蛋白的杂交瘤细胞株,命名为4G8和6B12,其亚型均为Ig G1型,并且识别于不同的抗原位点。经间接免疫荧光检测,MAb 4G8和6B12均能够与DTMUV发生特异性反应。本研究所制备的MAb为进一步鉴定DTMUV以及分析囊膜糖蛋白E的结构和功能奠定了基础。     

副猪嗜血杆菌β-半乳糖苷酶的原核表达与活性检测

克隆表达副猪嗜血杆菌β-半乳糖苷酶(BgaC),并测定其酶学特性。以副猪嗜血杆菌SH0165菌株基因组为模板,将BgaC基因的序列(1 791bp)克隆到pET32a质粒上,并电转化BL21表达菌株。以His标签融合蛋白纯化操作方法纯化表达产物。用聚丙烯酰胺凝胶电泳测定β-半乳糖苷酶的天然分子质量,以邻硝基苯β-D-半乳吡喃糖苷为底物测定其酶学特性。结果表明,在大肠埃希菌BL21中成功表达了副猪嗜血杆菌的BgaC基因,经鉴定pET32a+BgaC重组菌表达的蛋白大小为82.4ku。纯化后BgaC的酶比活力为1 795U/mg,pET32a+BgaC重组蛋白的最适pH为6~7,最适温度为30℃~37℃。副猪嗜血杆菌β-半乳糖苷酶(BgaC)具有糖苷酶活性能够介导糖蛋白的降解,在氨基酸序列上存在高度保守的区域,在生物技术领域具有广泛的应用前景。     

O型口蹄疫病毒VP1基因的原核表达及间接ELISA检测方法的建立

表达O型口蹄疫病毒VP1蛋白,用于O型口蹄疫病毒的检测.以质粒T234/FMDV为模板,PCR扩增VP1基因片段,构建重组质粒pET-41b/VP1,转化表达菌BL21(DE3),IPTG诱导,SDS-PAGE凝胶电泳和Western blot进行分析检测,目的蛋白经镍离子亲和层析纯化,以纯化的目的蛋白包被,建立了间接...     

犬冠状病毒N蛋白的原核表达及其多克隆抗体的制备

本研究旨在克隆犬冠状病毒(canine coronavirus,CCV)N基因,体外表达N蛋白,并制备抗该蛋白质的多克隆抗体,用于CCV的诊断及其抗原的检测。参考GenBank中CCV的N基因序列(登录号:KY063618.2),选择CCV流行毒株的N基因,通过对该基因密码子进行优化和基因合成,最后选择一段有效基因构建重组表达质粒pET-B2M-N,将成功构建的重组质粒转化大肠杆菌DH5α感受态细胞,挑取阳性克隆提取质粒,转化大肠杆菌BL21(DE3)感受态细胞,通过0.5mmol/L IPTG 30℃进行诱导表达。结果表明,优化诱导条件后成功表达出大小约为49ku的重组蛋白。将重组蛋白与弗氏佐剂按一定比例混合,每隔2周免疫G767、G768两只日本大耳白兔数次,用间接ELISA检测G768抗体效价可达1∶512 000,选用G768抗体进行抗体纯化,纯化后浓度可达10mg/mL,用间接ELISA、Western blotting和间接免疫荧光试验对N蛋白纯化后制备的兔多克隆抗体进行检测分析,表明表达的重组N蛋白免疫原性良好,制备的多克隆抗体具有良好的反应原性。本研究为犬冠状病毒抗原抗体检测以及靶标CCV诊断试剂盒的建立奠定了一定的基础。     

鲤春病毒血症病毒核蛋白的原核表达及初步鉴定

为原核表达鲤春病毒血症病毒(SVCV)核(N)蛋白,本研究采用RT-PCR方法扩增SVCV N蛋白基因(SVCV-N),克隆于原核表达载体pET-28a(+)中,并转化到大肠杆菌Rosetta中进行表达.SDS-PAGE分析表明,SVCV-N基因在大肠杆菌中获得高效表达,表达产物约47 ku,与预期相符.Western blot检测表明,该重组蛋白可以被SVCV阳性血清所识别.     

鲤春病毒血症病毒单克隆抗体的制备及其特性鉴定

为获得针对鲤春病毒血症病毒(SVCV)特异性的单克隆抗体(MAb),以纯化的SVCV为抗原,免疫BALB/c小鼠.将免疫鼠的脾细胞与SP2/0骨髓瘤细胞融合,采用间接ELISA法筛选获得4个能稳定分泌抗SVCV MAb的杂交瘤细胞株;4个杂交瘤细胞制备腹水的MAb效价为1:160 000～1:640 000.亚型鉴定结果表明,这些MAb分属2个亚型(1F1、3E1,IgG2a;3F5、4F9,IgGl),轻链均为K链.Western blot分析显示,MAb1F1、3F5、4F9能特异性地识别SVCV的N蛋白(47 ku),3E1能特异性地识别SVCV的G蛋白(69 ku).采用相加ELISA法对抗原表位分析结果显示,1F1、3F5、4F9可能识别相同的表位,3E1则识别不同的表位.间接免疫荧光试验结果显示4株MAb均能对染毒病灶产生特异性的荧光染色.这些MAb的制备为SVCV免疫学检测方法的建立奠定了基础.     

Immunoenzyme (ELISA) diagnosis of spring viremia in carp

The enzymoimmunologic (ELISA) method was used to diagnose spring viremia in carp. The specific antibodies to Rhabdovirus carpio in the fish sera were detected by this method. Reaction specificity was tested by the use of viral and control antigens, by examination of positive and negative sera and by serum-free control incubation. Applying the ELISA method, the antiviral antibodies can be detected after infection or vaccination: this method is therefore suitable for thorough studies and when choosing the appropriate treatments and preventive measures.     

鲤鱼春季病毒出血症病毒G基因在昆虫细胞中的表达与鉴定

采用RT-PCR方法扩增鲤鱼春季病毒出血症病毒（SVCV）的糖蛋白（G）基因,将PCR产物插入到杆状病毒转移载体pFastBac 1中,获得重组转移载体pFastBac 1-G,将其转化入含有Bacmid的DH10Bac感受态细胞中,经3种抗性和蓝白斑筛选,获得含有G基因的重组穿梭质粒rBacmid-G。在脂质体转染试剂的介导下,将rBacmid-G转染sf9细胞,获得重组杆状病毒。提取重组杆状病毒基因组,用M13引物PCR鉴定。对重组杆状病毒感染的sf9细胞,通过电镜观察、SDS-PAGE、Western blotting进行检测,结果表明,重组蛋白在sf9细胞中获得正确表达,相对分子质量约58 000,与鼠抗SVCV阳性血清具有良好的反应原性。本试验为研究鲤鱼春季病毒出血症病毒G蛋白的生物学活性和亚单位疫苗的研制奠定了基础。     

Monoclonal-Antibody-Based Immunodot Assay Distinguishes between Viral Hemorrhagic Septicemia Virus (VHSV) and Infectious Hematopoietic Necrosis Virus (IHNV)

Abstract

An immunodot assay has been developed with two monoclonal antibodies that recognize conserved epitopes on the nucleoproteins of viral hemorrhagic septicemia virus (VHSV) and infectious hematopoietic necrosis virus (IHNV). Monoclonal antibody 1NDW14D, which recognizes a conserved epitope on the nucleoprotein of IHNV, recognized 80 of 81 IHNV isolates spotted on nitrocellulose, but none of 8 VHSV isolates. Monoclonal antibody IP5B11, which recognizes a conserved epitope on the nucleoprotein of VHSV, reacted with all eight isolates of VHSV, but with none of the IHNV isolates. Neither monoclonal antibody bound to other rhabdoviruses spotted on nitrocellulose: spring viremia of carp virus (SVCV), pike fry rhabdovirus (PFRV), a new Danish eicosid rhabdovirus unrelated to PFRV, and rhabdovirus anguilla (EVX).     

Development and characterization of monoclonal antibodies to spring viraemia of carp virus

Five monoclonal antibodies (mAbs) against spring viraemia of carp (SVCV0504, isolated from common carp in China) were produced from mice immunized with purified virus preparations. The virion of SVCV contains five structural proteins, representing the nucleoprotein (N), phosphoprotein (P), matrix protein (M), glycoprotein (G) and RNA-dependent RNA polymerase (L). Western blotting analysis revealed that three mAbs (1H5, 1E10, and 1H7) recognized specifically to a single protein of 47kDa (N), the mAb 3G4 reacted with two SVCV0504 proteins of 69kDa (G) and 47kDa (N), while the mAb 1A9 reacted with three SVCV0504 proteins of 69kDa (G), 50kDa (P), and 47kDa (N). By indirect ELISA, two mAbs (1H5 and 1H7) showed cross-reactivity with pike fry rhabdovirus (PFRV), but no cross-reactions with the Siniperca chuatsi rhabdovirus (SCRV), Scophthalmus maximus rhabdovirus (SMRV), Paralichthys olivaceus rhabdovirus (PoRV) were demonstrated with the five mAbs. Indirect immunofluorescence showed intense fluorescence in the cytoplasm of the SVCV0504-infected epithelioma papulosum cyprini (EPC) cells in areas corresponding to the location of granular structures. The sucrose gradient-purified SVCV0504 particles could be detected successfully by these mAbs using immunodot blotting. mAb 1A9 could completely neutralize 100 TCID(50) (50% tissue culture infective dose) of SVCV0504 at a dilution of 1:8. This is the first report of development of the neutralizing mAbs against SVCV. The mAb 1A9 was analyzed further and could be used to successfully detect viral antigens in the infected-EPC cell cultures or in cryosections from experimentally infected crucian carp (Carassius auratus) by immunohistochemistry assay. Furthermore, a flow cytometry procedure for the detection and quantification of cytoplasmic SVCV0504 in cell cultures was developed with mAb 1A9. At 28h after inoculation with the virus (0.01PFU/cell), 10.12% of infected cells could be distinguished from the uninfected cells. These mAbs will be useful in diagnostic test development and pathogenesis studies for fish rhabdovirus.     

鲤春病毒血症病毒糖蛋白的高效表达和纯化

本研究从鲤春病毒血症病毒（Spring viremia of carp virus,SVCV）SVCV-741毒株克隆鲤春病毒血症病毒糖蛋白基因（sue—g）,将svc-g亚克隆到原核表达载体pET-28a,转化大肠杆菌E．coli BL-21（DE3）后,用IPTG诱导培养,获得菌体总蛋白。用SVCV毒株免疫山羊所得到的抗血清作为一抗进行免疫印迹实验,结果在硝酸纤维素滤膜上检测到50～71 kDa之间的特异性免疫条带,与SVCV糖蛋白预测分子量一致,研究证明了工程茵表达获得的重组蛋白具有与SVCV毒株相同的免疫原性,也证明了该蛋白的糖基化对其免疫表位是非必需的。本研究进一步通过发酵基因工程菌和蛋白质纯化过程,获得大量的鲤春病毒血症病毒糖蛋白,为后期免疫动物获得抗血清储备了原料,也为SVCV的免疫学检测方法的建立奠定了物质基础。     

从江县鲤爆发性死亡病例实验室诊断

2018年10月贵州省从江县某水产养殖专业合作社鲤爆发死亡,本研究对死亡病例进行了流行病学调查、病理学观察、寄生虫学检查、细菌分离鉴定和病毒PCR检测等诊断。结果显示:病鲤病变以鳃丝溃烂、体表出血、肛门红肿和眼球凹陷为主要特征,组织的主要病变是肾小球萎缩出血、肾小囊空腔、鳃丝肿胀粘连及上皮细胞脱落等;细菌分离培养可得到圆形凸起、表面光滑的灰白色菌落,经染色镜检、生理生化鉴定和16S rRNA基因测序分析,鉴定该分离菌为嗜水气单胞菌;PCR检测显示鲤浮肿病毒(Carp edema virus,CEV)为阳性,未检出鲤春病毒血症病毒(Spring viremia of carp virus,SVCV)和鲤疱疹病毒(Koi herpesvirus,KHV);显微镜观察亦未见到寄生虫虫体;分别取分离菌和鲤浮肿病毒阳性病例组织悬液进行人工感染试验,均可引起健康鲤发生死亡。上述结果表明,从江县鲤的死亡是嗜水气单胞菌和鲤浮肿病毒混合感染所致。     

Molecular cloning of type I collagen cDNA and nutritional regulation of type I collagen mRNA expression in grass carp

Grass carp (Ctenopharyngodon idellus) are important Chinese freshwater fish, and in China, the faba bean has been used as the sole food source for grass carp to transform them into crisp grass carp. Because of this, crisp grass carp has become an economically important fish because of its increased muscle hardness. To study the nutritional regulation of type I collagen in faba bean‐fed grass carp, we isolated type I collagen alpha 2 (COL1A2) on the basis of our isolation of COL1A1. The COL1A2 cDNA was found to be 4899 bp in length and included a 4059‐bp coding sequence (CDS) and encoded a polypeptide of 1352 AA. The protein peptide molecular weight was 127.39 kD, and the theoretical isoelectric point was 9.37. The COL1A2 protein possessed five α‐helixes, eight β‐sheets, 16 regions of triple helical repeats, 21 low‐complexity regions, 10 function domains and two zinc‐binding sites; however, no calcium‐binding sites were observed. The mRNA expression of COL1A1 and COL1A2 was assessed in eight tissues (muscle, hepatopancreas, intestine, gills, skin, fin, kidney and spleen) from grass carp and crisp grass carp by semi‐quantitative RT‐PCR. Expression of COL1A1 in the muscle, intestines and skin of crisp grass carp was higher than that in grass carp, and expression of COL1A2 in the muscle, gills, fin and skin of crisp grass carp was higher than that in grass carp. In the muscle of crisp grass carp, expression of COL1A1 and COL1A2 was higher than that in grass carp, which was further confirmed by real‐time PCR, and collagen content also was enhanced. These results demonstrated that type I collagen was closely related to the increased muscle hardness of faba bean‐fed grass carp.