口蹄疫病毒VP2基因重组表达载体的构建及其稳定表达细胞系的建立

本试验旨在构建Asia 1型口蹄疫病毒(FMDV)的VP2基因重组表达载体,并建立稳定表达VP2基因的BHK-21细胞系。利用RT-PCR方法扩增Asia 1型FMDV的cDNA,获得VP2基因完整的编码区,构建可表达VP2的带有绿色荧光蛋白标记基因的pIRES2-EGFP-VP2重组表达载体。经鉴定正确后,利用LipofectamineTM2000将重组质粒转染293T细胞,通过Western Blot技术检测VP2蛋白的瞬时表达;然后再转染BHK-21细胞,通过G418筛选,形成单克隆细胞系,经荧光筛选到表达EGFP的抗性单克隆细胞,扩繁培养克隆细胞,再通过West-ern Blot技术检测其VP2的表达,最终筛选到稳定表达FMDVVP2基因的BHK-21细胞系。结果表明,VP2基因重组表达载体pIRES2-EGFP-VP2构建正确,能够在293T细胞内瞬时表达;转染BHK-21细胞,经G418筛选到表达VP2基因的BHK-21细胞克隆,经长达60d的传代,获得了稳定表达VP2基因和EGFP的BHK-21细胞系。上述结果表明,我们建立了稳定表达VP2基因的BHK-21细胞系,为进一步探讨VP2基因在FMD...     

表达非洲猪瘟病毒p54蛋白重组伪狂犬病病毒的构建及鉴定

试验旨在构建能高效表达非洲猪瘟病毒（African swine fever virus,ASFV） p54蛋白的重组伪狂犬病病毒（Pseudorabies virus,PRV）。通过无缝克隆构建含有PRV TK基因同源臂和绿色荧光蛋白（GFP）报告基因的PRV通用转移载体pCAGIG-TK_（l+r）,参考China/2018/AnhuiXCGQ株基因序列,优化合成E183L基因,并连入通用转移载体,构建重组中间转移质粒pCAGIG-TK_（l+r）-p54;重组质粒ScaⅠ酶切线性化后经脂质体介导转染BHK-21细胞,6 h后感染0.1个感染复数（MOI） PRV变异株,出现病变后通过空斑挑选和PCR鉴定纯化重组PRV,进一步通过Western blotting和间接免疫荧光试验（IFA）检测外源蛋白表达,并对重组病毒的遗传稳定性和增殖特性进行研究。结果显示,转染重组质粒pCAGIG-TK_（l+r）-p54的BHK-21细胞24 h后可观察到绿色荧光,说明重组质粒成功转入BHK-21细胞;纯化后的重组病毒表达绿色荧光蛋白且含有ASFV E183L基因,Western blotting和IFA结果证实重组PRV在BHK-21细胞中能表达p54外源蛋白,在26 ku处呈现特异性条带,且能与ASFV阳性血清发生特异性反应,免疫原性较好;重组病毒在BHK-21细胞上连续传代20次均能检测到ASFV E183L基因,遗传稳定性较好;一步生长曲线显示,重组病毒与亲本病毒的增殖特性差异不大,且二者的最高病毒滴度分别为10^7.34/0.1 mL和10^7.61/0.1 mL,外源片段的插入不影响重组病毒在细胞上的增殖能力。本研究成功获得了表达ASFV p54蛋白的重组病毒rPRV-p54,为进一步研究p54蛋白的免疫原性及开发非洲猪瘟多基因重组PRV载体疫苗奠定了基础。     

稳定表达施马伦贝格病毒核衣壳蛋白的BHK-21细胞系的建立

为建立稳定表达施马伦贝格病毒(SBV)核衣壳(N)蛋白的BHK-21细胞系,本研究在SBV-N蛋白编码基因的C端加入6个组氨酸(6×His)标签,将其克隆至慢病毒载体p LV-EGFP-C中构建重组慢病毒质粒p LV-EGFP-SBV-N,将其与慢病毒包装质粒p Helper1.0和p Helper2.0共转染HEK-293T细胞,包装表达SBV-N蛋白的慢病毒。将重组慢病毒在聚凝胺(Polybrene)的介导下感染BHK-21细胞,采用嘌呤霉素(Puromycin)法和细胞有限稀释法筛选出一株稳定表达SBV-N蛋白的BHK-21细胞系,命名为BHK-21-EGFP-SBV-N。间接免疫荧光试验进一步表明,该细胞系能够被SBV抗体阳性动物血清和特异性单克隆抗体2C8识别。稳定表达SBV-N蛋白的BHK-21细胞系的建立,为SBV血清学检测方法的建立提供材料。     

禽白血病病毒gp85蛋白在293T细胞中的表达及分析

为获得293T细胞表达的ALV-J gp85蛋白,研究通过PCR扩增ALV-J gp85基因,利用基因克隆技术克隆pMD-18T-gp85并测序,进而构建表达质粒p EGFP-N1-gp85。利用293T细胞对重组表达质粒进行表达,通过荧光显微镜和Western blot检测重组表达质粒(pEGFP-N1-gp85)的表达情况。结果显示,pEGFP-N1-gp85重组表达质粒在293T细胞中均匀分布,说明pEGFP-N1-gp85重组表达质粒在293T细胞中表达;pEGFP-N1-gp85重组表达质粒在293T细胞中表达的蛋白质分子质量约为60 ku。结果表明,成功构建了真核表达质粒pEGFP-N1-gp85,并在293T细胞中获得了表达,为研制ALV-J-gp85 DNA核酸疫苗提供了科学支撑。     

禽白血病病毒衣壳蛋白P27慢病毒载体的构建及其在鸡肝癌细胞中的表达

为构建禽白血病病毒(ALV)衣壳蛋白P27慢病毒表达载体,并检测其在鸡肝癌细胞LMH中的表达,试验以实验室前期构建的pcDNA3.1-p27为模板,扩增p27基因,克隆入pLVX-IRES-ZsGreen1载体,构建的重组质粒命名为pLVX-p27,与辅助质粒psPAX2和pMD2.G共转染至HEK293T细胞,包装获得表达p27基因的重组慢病毒。将慢病毒上清感染293T和LMH细胞,检测细胞中p27基因的转录水平和蛋白表达水平。结果显示:重组质粒pLVX-p27构建正确,收集的慢病毒上清滴度为9×10⁴TU/mL;实时荧光定量PCR、Western blot和共聚焦荧光试验结果显示P27蛋白主要定位于胞浆,p27基因的RNA和蛋白表达量在感染后96 h内随着感染时间延长逐渐升高。研究表明:表达p27基因的慢病毒包装成功,并且能感染293T及禽源LMH细胞,为进一步研究P27的生物学功能提供了工具。     

融合表达禽白血病env基因和IgG-Fc基因对鸡免疫效果研究

为研究鸡IgG-Fc作为分子佐剂是否能够增强J亚群白血病病毒env基因核酸疫苗的免疫效果,本研究克隆鸡IgG-Fc、禽白血病病毒-J(ALV-J)env基因,通过overlap-PCR将两个基因串联,构建pcDNA-env-Fc重组质粒,转染HEK293T细胞,48 h后经间接免疫荧光试验证明外源基因能够在细胞内表达。将pcDNA-env-Fc重复免疫SPF鸡3次,记录免疫过程中ALV-J env抗体动态变化,通过ELISA试剂盒检测鸡体内ALV-J env基因特异性抗体含量,结果显示第5周ALV-J抗体水平显著高于对照组(p0.05),尤其是IgG-Fc片段作为分子佐剂比ALV-J env基因疫苗更能显著刺激机体产生抗体。结果表明IgG-Fc片段可以作为ALV-J env基因疫苗有效的分子佐剂。     

新城疫病毒Clone 30株辅助表达系统的构建及真核表达

为研究新城疫病毒NP、P和L蛋白作用机理和新城疫病毒反向遗传操作系统,构建新城疫病毒Clone 30株NP、P和L基因的真核表达载体。根据Gen Bank中新城疫病毒Clone 30株的全长序列(Y18898.1),设计3对特异性引物,用RT-PCR法扩增出新城疫病毒Clone 30株的NP、P和L基因,将其克隆到真核载体pCI-neo上。通过酶切和测序验证克隆正确,得到重组质粒pCI-NP、pCI-P和pCI-L,瞬时转染到BHK-21细胞中。经RT-PCR、Western blot、间接免疫荧光试验分别检测NP、P和L蛋白在BHK-21细胞中的表达。结果表明,重组质粒pCI-NP、pCI-P和pCI-L构建成功,为后期新城疫病毒反向遗传操作系统的构建奠定了基础。     

禽流感病毒血凝素与核蛋白在重组禽痘病毒中的共表达

为克服禽流感病毒(AIV)血凝素(HA)仅诱导机体产生亚型特异性免疫应答的不足,本研究拟将病毒核蛋白(NP)基因与HA基因在重组禽痘病毒中实现共表达。首先构建转移载体,从测序质粒pUCNP中切下目的基因克隆到载体pSY538早晚期启动子LP2EP2的下游,再将含有禽痘病毒早晚期启动子LP2EP2的NP基因片段亚克隆到已有的AIVHA基因重组禽痘病毒转移载体中,即得到同时含有HA和NP两种基因的重组转移载体pSY(HA NP)。将转移载体脂质体转染已感染禽痘病毒亲本株S-FPV-017的鸡胚成纤维细胞。根据报告基因β-半乳糖苷酶(LacZ)基因的表达,蓝白斑法筛选重组病毒,经数轮蚀斑纯化,PCR鉴定及West-ern-blot分析,结果表明所获得的重组病毒能高效表达AIVHA及NP两种蛋白。此研究为进一步研制更为有效的禽流感基因工程活病毒载体疫苗奠定了基础。     

RCAS(J)-Luciferase重组病毒拯救及其相关生物学功能鉴定

RCAS载体系列是基于A型罗斯肉瘤病毒(RSV-A)所改造而成的反转录病毒感染性克隆,转染易感细胞后,能够产生高滴度的RSV-A病毒。同时,RCAS载体可携带外源基因进入靶细胞,从而进行蛋白的高效表达。为了获取滴度高且易于检测的RSV,进行ALV-J受体方面的研究,本研究将RCAS(A)-GFP载体中RSV-A的囊膜蛋白基因替换为ALV-J的囊膜蛋白基因,并将绿色荧光蛋白报告基因(gfp)替换为海参荧光素酶(luciferase)报告基因,构建带有luciferase报告基因的囊膜蛋白为ALV-J囊膜蛋白的RSV重组病毒。经验证,本研究所构建的重组病毒,与传统的ALV-J株相比,具有复制能力强,病毒滴度高等优点,而且能够通过ALV-J特异性受体ch NHE1感染ALV-J非允许细胞系,有利于病毒感染初期的检测和定量,为病毒与其受体之间相互作用的研究奠定了基础。     

禽呼肠孤病毒σA蛋白在HEK293T细胞中的表达

为了正确表达禽呼肠孤病毒(ARV)σA蛋白,试验拟构建σA基因的真核表达质粒,并将其在人胚肾细胞(HEK293T)中准确表达,参照GenBank中ARV S2基因序列(登录号为KF741763. 1)设计特异性引物,以pMD18-T-σA重组载体为模板,应用PCR的方法扩增σA基因的特异性序列,并将其克隆到p MD18-T载体中,构建重组pMD18-T-σA表达质粒,再用限制性内切酶KpnⅠ和NotⅠ同时双酶切pMD18-T-σA和真核表达质粒pEF1α-HA,将胶回收的σA基因和pEF1α-HA进行连接,构建真核表达质粒pEF1α-HA-σA。真核表达质粒经菌落PCR、双酶切和测序验证正确后,将其转染HEK293T细胞,于24 h后收取蛋白质,通过Western-blot验证目的蛋白。结果表明:本试验成功克隆了ARVσA基因,构建了其真核表达质粒pEF1α-HA-σA,并在HEK293T细胞中表达。说明该蛋白可以在HEK293T细胞中准确表达。     

Leiomyoma of a kidney in a dog: a rare diagnosis

A five-year-old, neutered male, Bernese Mountain Dog was referred because of a two-week history of hematuria and a one-week history of polydipsia and polyuria. Palpation of the dorsomedial mesogastrium revealed a mass on the left side, which was seen via radiography and ultrasonography to be attached to the left kidney. The left kidney and the attached mass were excised surgically, and the dog had an uneventful recovery. Histological examination of the mass revealed a dense proliferation of non-polymorphic spindle cells, which stained positive for smooth muscle actin via immunohistochemistry. Leiomyoma of the kidney was diagnosed. Postoperatively, there was mild azotaemia, which did not affect the general condition of the dog and was still present 15 months after surgery. Leiomyoma of the kidney is a benign tumor, and hematuria may be the only clinical sign.     

Gastrocutaneous fistula as a result of migration of a foreign body in a dog

A six-year-old, female Tibetan terrier was referred for investigation of a non-healing wound on the left caudal thorax. A subcutaneous swelling had initially developed on the chest wall, followed by a draining tract from which seropurulent fluid drained for two months. There had been no response to antibiotic treatment. Following radiographic and ultrasonographic examinations, a bone sequestrum from a fractured rib or a foreign body was suspected. Surgical exploration of the wound identified a sinus tract and a wooden foreign body (an ice-lolly stick) was located in subcutaneous tissues. Partial wound dehiscence of the surgical site occurred postoperatively, but healed after 10 days. One month later, fluid began to discharge from the area again. Further surgical exploration confirmed a gastrocutaneous fistula. Dissection of the fistula and surgical closure of the stomach, body wall and skin led to resolution of all signs.     

Simultaneous presence of a seminoma and a leiomyoma in the testes of a horse

An 18‐year‐old stallion was presented for castration because of insidious, bilateral scrotal enlargement of one year's duration. The left testis was firm, while the right was soft and lobulated; both were larger than normal. Palpation of the scrotum and its contents did not cause the horse to show signs of discomfort. Ultrasonography of scrotal contents revealed abnormal, heterogeneous tissue with ill defined regions of hyper‐ and hypoechogenity throughout both testes. Several hours after admission the horse developed severe signs of colic. On the basis of anamnesis, clinical findings, and results of ultrasonography and transrectal palpation bilateral testicular neoplasia and incarcerated inguinal hernia were tentatively diagnosed. Because the horse's owner did not consent to surgical treatment, the stallion was subjected to euthanasia. Histological and immunohistochemical examination of the testicular tissue collected post mortem revealed a seminoma in the left testis and a leiomyoma in the right testis. The post mortem examination also revealed incarceration of the small intestine in addition to the testicular tumours. To our knowledge, this is the first report of the simultaneous presence of bilateral, yet different testicular tumour types in a stallion.