用于DNA转染的PRRSV全长感染性cDNA克隆改建及应用

[目的]利用核酶自我剪切功能使PRRSV的基因组获得1个精确的基因组3′末端,提高全长感染性cDNA克隆的病毒拯救效率。[方法]用3步PCR方法将获得含有丁型肝炎病毒核酶序列的片段并将其克隆到PRRSV全长cDNA克隆pAPRRS的poly(A)下游,再通过酶切,连接将牛生长激素多聚腺甘酸转录终止序列插入到核酶序列后,构建成全长感染性cDNA克隆pAPRRS-HB,新构建的克隆转染MARC-145细胞,72h后用间接免疫荧光检测病毒N蛋白和非结构蛋白2(nsp2)的表达,并检测细胞上清中病毒的滴度。[结果]成功构建了含有核酶序列的PRRSV基因组全长感染性cDNA克隆pAPRRS-HB。新构建的全长感染性cDNA克隆能够较好地拯救出病毒,拯救效率比pAPRRS提高10倍左右。[结论]该结果为研究PRRSV基因结构与功能奠定了基础。

HFW热处理线回火炉均匀性研究

热处理是油井管生产中的重要特殊工序,对管子的力学性能、抗腐蚀性能具有决定性作用。HFW热处理线承担着无缝钢管厂中大口径套管、结构管等高附加值产品的热处理业务,由于产线设计的特性及设备使用损耗,生产的管子性能波动较大。为满足高钢级抗挤毁、抗硫化氢腐蚀套管严苛的生产要求,通过黑匣子试验、增加烧嘴监控、减少孔洞吸风等方式,研究改善回火炉炉膛气氛的均匀性。

衣壳蛋白缺失突变对登革病毒致病性及免疫原性的影响

在登革2型病毒中国分离株(DEN2—43)的感染性全长cDNA克隆的基础之上,利用融合PCR技术构建衣壳蛋白基因缺失的全长cDNA．将其线性化并体外转录成RNA后,经电穿孔法导入宿主细胞获得缺失突变病毒,对其致病性和免疫原性进行了观察．结果显示,随着衣壳蛋白缺失氨基酸残基数目的增加,病毒在敏感细胞中的增殖能力逐渐减弱,而衣壳蛋白第3个α螺旋序列缺失的突变体则完全丧失感染性．突变病毒对乳鼠的致病性也随之减弱,缺失10个氨基酸残基使病毒几乎完全丧失乳鼠致病力．同时缺失突变病毒可诱导小鼠产生高水平IgG抗体．表明登革病毒衣壳蛋白具有功能灵活性,可作为减毒突变的靶位点．该结果为深入探讨登革病毒基因组结构与功能的关系及研制新型登革减毒疫苗奠定了基础．

表达抗G250人源性抗体腺病毒对肾癌细胞的影响

目的检测腺病毒Ad-G250表达的G250全长人源性抗体的生物学活性及其对肾癌细胞的影响。方法扩增纯化腺病毒Ad—G250、Ad—EGFP（对照病毒）。病毒感染LO-2细胞，ELISA法检测细胞培养液中抗体的表达量。收集病毒感染后的细胞上清液进行纯化，Westernblotting检测纯化抗体的相对分子质量及其与细胞表面G250抗原的结合能力。免疫组化法检测Ad—G250表达的抗体是否具有生物学活性。CCK-8法检测Ad—G250对肾癌Ketr-3及ACHN细胞增殖的影响。AnnexinV—PE／7-AAD法检测Ad—G250对‘肾癌Ketr-3及ACHN细胞凋亡的影响。结果病毒Ad—G250感染LO-2细胞后G250抗体的表达量随着感染天数的增加而增加。Westernblotting实验显示Ad—G250能够表达G250抗体的轻链和重链，电泳图上该抗体能使G250抗原阳性的Ketr-3和786-O细胞在相对分子质量58×10’附近出现反应条带，而G250抗原阴性的ACHN和HK-2细胞在相应位置无反应条带。细胞免疫组化实验显示Ketr-3细胞膜被染成棕黄色，而ACHN细胞未见着色。CCK-8实验结果显示，Ad—G250对Ketr-3细胞有抑制作用，而对ACHN细胞的抑制作用不明显；Ad—G250抑制Ketr-3细胞增殖存在浓度及时问依赖性。凋亡实验显示，Ad—G250诱导Ketr-3细胞凋亡作用和ACHN细胞相比差异具有统计学意义，Ad—G250诱导Kert-3凋亡作用和Ad—EGFP相比差异有统计学意义。结论腺病毒Ad—G250成功表达出具有生物学活性的人源性G250抗体，且Ad—G250可抑制表达G250抗原的肾癌细胞增殖，诱导其凋亡。

猪瘟疫苗的研究现状与发展趋势

猪瘟是由猪瘟病毒感染引起的一种急性、热性、高度接触性传染病,主要特征是发病急、高热稽留和细小血管壁变性,从而引起泛发性小点状出血、梗死和坏死。该病传染性强,病死率高,对养猪业危害巨大。OIE将其列为法定报告疾病,我国将其列为一类动物疫病。猪瘟病毒是其病原体,尽管猪瘟病毒各个毒株的毒力不同,但是它们都使养猪业产生了巨大损失,威胁着全世界的猪肉生产和国家人口的粮食安全。

一株A型口蹄疫流行毒株全序列的测定及其全长感染性克隆的构建

【目的】测定一株A型口蹄疫流行毒株的全基因组序列,并构建其全长感染性克隆。【方法】参照已公布的A型口蹄疫病毒序列设计引物,将分离的口蹄疫病毒株A/Sea-97/CHA/2014全基因组分为4个重叠的片段进行RT-PCR扩增,并对其进行序列测定与分析。利用酶切连接法将4个基因片段依次克隆至p Blue Script SKhdv载体中,构建该流行毒株的全长c DNA克隆p QAHN。pQAHN经NotⅠ线性化后转染表达T7 RNA聚合酶的BSR/T7细胞,拯救病毒。【结果】口蹄疫病毒全基因组序列测定结果表明该毒株基因组全长8 171 bp[不包括poly(C)区段和poly(A)尾巴],开放阅读框为6 996 bp,编码2 332个氨基酸,5′和3′非编码区分别为1 091 bp和95 bp。VP1系统发生树分析表明该毒株与A/GDMM/CHA/2013毒株亲缘关系最近,相似性为99.1%。线化全长质粒转染BSR/T7细胞68 h后可观察到典型的细胞病变。拯救病毒的间接免疫荧光、RT-PCR和序列测定结果表明成功拯救出了具有感染性的FMDV。拯救病毒与亲本病毒的噬斑表型及生长曲线试验表明二者具有相似的生长表型和增殖能力。【结论】该研究为我国口蹄疫病原生态分布、分子流行病学调查以及A型FMD新型疫苗的研究提供了有益的材料。

登革2型病毒中国分离株感染性全长cDNA克隆的构建与鉴定

目的:构建登革2型病毒中国分离株(DEN2-43)的感染性全长cDNA克隆。方法:根据我室测定的DEN2-43株病毒全基因组序列,利用长链RT-PCR及融合PCR技术扩增此病毒基因组全长cDNA分子,并将其克隆至低拷贝载体pW SK29中构建该病毒株的全长cDNA克隆。将此克隆体外转录后,通过电穿孔导入宿主细胞获得恢复病毒。结果与结论:构建的DEN2-43基因组全长cDNA克隆具有感染性,所获得的恢复病毒具有与原型病毒类似的生物学性质及小鼠乳鼠神经毒力,且可稳定传代。该感染性克隆的构建为深入探讨登革病毒的致病机制及研制新型登革疫苗奠定了基础。

型内嵌合口蹄疫病毒全长感染性cDNA克隆的构建

【目的】近年来,O型口蹄疫的不断暴发严重危害了我国畜牧业的发展,其病原——O型口蹄疫病毒已演化出3种谱系:中国型猪毒系、泛亚系和缅甸98系。其中中国型猪毒系病毒高度嗜猪,对养猪业危害最大。目前应用的疫苗已不能有效保护中国型猪毒系变异株的流行,这给我国猪口蹄疫的防控带来了极大的困难。为了进一步发展免疫原性好、抗原谱广的猪O型口蹄疫疫苗候选株,本研究以O/HN/93现用疫苗毒株的感染性克隆为骨架,用流行的新猪毒系病毒的部分VP3和VP1基因(主要是替换VP1蛋白上的B-C环和G-H环)替换疫苗毒株的相应部分,构建了嵌合的FMDV全长cDNA克隆。【方法】线化的嵌合全长质粒和表达T7 RNA聚合酶的真核质粒pcDNAT7P共转染BHK-21细胞,体内转录拯救嵌合病毒。【结果】嵌合全长质粒转染BHK-21细胞36h后,出现明显的FMDV致细胞病变效应。对收获的病毒分别用RT-PCR、间接免疫荧光、电子显微镜观察结果证实成功拯救到嵌合的FMDV。拯救的病毒乳鼠致病性试验结果表明该拯救病毒对乳鼠的致病力减弱。该嵌合病毒的成功拯救为研制口蹄疫新型疫苗等奠定了基础。

猪瘟病毒的分子生物学研究进展

本文概述了猪瘟病毒的基因结构和功能 ,猪瘟的分子生物学诊断技术和基因疫苗 ,以及猪瘟病毒全长感染性 c DNA的研究进展。为进一步研究猪瘟病毒的复制机理、毒力及其决定因素、致弱机理、致病机理、基因产物的功能、宿主嗜性及标记疫苗的开发提供理论参考。

衣壳蛋白缺失突变登革病毒的制备与鉴定

目的制备登革2型病毒中国分离株(DEN2-43)的衣壳蛋白缺失突变病毒。方法在DEN2-43株病毒感染性全长cDNA克隆的基础之上,利用融合PCR技术构建衣壳蛋白基因缺失的全长cDNA,将其线性化并体外转录成RNA后,经电穿孔法导入宿主细胞获得衣壳蛋白缺失突变病毒。结果序列比对表明,所获得的恢复病毒带有与预期一致的缺失突变。结论成功制备衣壳蛋白缺失突变病毒,为进一步研究衣壳蛋白基因突变对登革病毒生物学特性的影响奠定了基础。

Effects of dendritic cells transfected with full-length wild-type p53 and stimulated by gastric cancer lysates on immune response

AIM: To investigate the effects of dendritic cells (DCs) transfected with full-length wild-type p53 and stimulated by gastric cancer lysates on immune response.METHODS: The wild-type p53 was transduced to DCs with adenovirus, and the DCs were stimulated by gastric cancer lysates. The surface molecules (B7-1, B7-2, MHC-I, MHC-II) of all DCs were detected by FACS, and the ability of the DCs to induce efficient and specific immunological response inanti-^51Cr-labeled target cells was studied. BALB/c mice injected with DCs and Mk28 were established, and CTL response in mice immunized with Lywt-p53DC was evaluated.Tumor-bearing mice were treated with Lywt-p53DC.RESULTS: The surface molecules of Lywt-p53DC had a high expression of B7-1 (86.70±0.07%), B7-2 (18.77±0.08%),MHC-I (87.20±0.05%) and MHC-II (56.70±0.07%); T lymphocytes had a specific CTL lysis ability induced by Lywt-p53DC; the CTL lysis rate was as high as 81%. The immune protection of Lywtp-53DC was obvious, the tumor diameter in Lywtp-53DC group was 3.10+0.31 ram, 2.73±0.23 ram,3.70±0.07 mm on d 13, 16 and 19, respectively, which were smaller than control, DC, wtp53DC and LyDC group (P<0.05). Tumor growth rate in Lywtp53DC group was slower than that in other groups (P<0.05).CONCLUSION: DCs transfected with wild-type p53 and stimulated by gastric cancer lysates have specific CTL killing activity.

乙型脑炎减毒活疫苗株全长感染性克隆的构建及表达外源基因的初步研究

通过构建乙型脑炎病毒减毒株SA14-14-2的全长cDNA克隆,来初步探讨将其作为表达载体的可行性,为下一步利用乙型脑炎病毒作为载体构建嵌合病毒打下基础。利用长片段RT-PCR的方法分两段扩增出乙型脑炎病毒cDNA,通过片段两端的酶切位点,将cDNA依次连接到pACYC184载体。进一步利用分子克隆的手段,在乙型脑炎病毒基因组cDNA的3′非编码区插入增强型绿色荧光蛋白(Ehanced green fluorescent portein,EGFP)基因作为报告基因,通过体外转录和转染,拯救乙型脑炎病毒和表达绿色荧光蛋白的乙型脑炎嵌合病毒。采用RT-PCR、蚀斑实验和荧光显微镜观察等方法对恢复病毒进行鉴定。对恢复病毒进行连续6次细胞传代,从病毒生长特性和结构基因稳定性的角度对恢复病毒传代稳定性进行研究。结果表明成功地扩增并构建得到乙型脑炎病毒的全长cDNA,在此基础上进一步构建得到了乙型脑炎嵌合病毒rJEV-EGFP全长cDNA,经过体外转录和转染获得了活的rJEV病毒及嵌合病毒rJEV-EGFP,并采用了多种方法对其进行了鉴定,拯救出的恢复病毒在已传代的代次内稳定性良好,嵌合病毒rJEV-EGFP可稳定地表达绿色荧光蛋白。本研究应用反向遗传学技术构建并在BHK-21细胞中成功地拯救出了rJEV和rJEV-EGFP活病毒,同时也表明乙型脑炎病毒SA14-14-2株可以作为载体来表达外源基因。

Development of an Improved DNA-launched Porcine Reproductive and Respiratory Syndrome Virus Reverse Genetics System

[Objective] This study was to improve the virus replication efficiency of full length infectious cDNA clones by making use of the ribozyme＇s self incision property.[Method] By employing three-step PCR,HDV ribozyme（HdvRz）cDNA was isolated,and cloned into the downstream flanking the genome of the porcine reproductive and respiratory syndrome virus,and into which the bovine growth hormone polyadenylation sequence（BGH）was inserted via enzyme digestion and ligation,yielding pAPRRS-HB.The newly constructed pAPRRS-HB was used to transfect MARC-145 cells,in which the N protein and non-structural protein（nsp2）were determined by indirect immunofluorescence assay after 72 h of expression;meanwhile the virus titer of cell supernatant was tested using TCID50 assay.[Result] pAPRRS-HB containing complete infectious PRRSV cDNA has been successfully developed,and it performed about 10-fold higher virus rescue rate than pAPRRS without the engineered ribozyme element.[Conclusion] The results laid a foundation for revealing the structure and function of PRRSV gene.

口蹄疫病毒Asia 1/JSWX株基因组全长感染性克隆的体外拯救与序列分析

通过反转录聚合酶链反应,获得了口蹄疫病毒(FMDV)Asia1/JSWX株基因组3′端长片段(长约7.5kb)和5′UTR中ploy(C)前后的2个短片段。5′UTR的2个短片段经融合PCR扩增得到长约710bp的片段。用引物在基因组5′末端引入AflⅡ酶切位点和T7启动子,在5′UTR内引入SpeⅠ酶切鉴定位点,在3′末端引入NotⅠ酶切位点,将融合片段和3′端长片段顺次连接到载体pSL1180。经T7体外转录系统获取的RNA转录本与脂质体共转染BHK21细胞。测序结果表明,构建的病毒基因组全长cDNA为8 197nt,分别包括1个长为1 095nt的5′UTR[含有1个17nt的ploy(C)];1个长6 990nt的ORF;1个长为93nt的3′UTR;之后是18nt的poly(A)尾巴。该全长cDNA克隆与Asia 1/Jiangsu/China/2005株基因组序列的同源性为98.4%。测序和酶切鉴定结果均表明,该口蹄疫病毒株全长cDNA克隆已构建成功,该方法极大地简化了获得FMDV全长cDNA克隆的过程。通过反转录聚合酶链反应、间接免疫荧光试验和蚀斑试验等鉴定,本试验获得了感染性分子克隆;体外拯救获得的基因工程病毒连续传代培养后,可致BHK21细胞产生病变。上述结果表明,构建的cDNA克隆可以作为基因操作的载体,为深入研究安全性好、稳定性高和免疫原性强的基因工程疫苗奠定了基础。

Isolation and Characterization of Calmodulin Gene of Alexandrium catenella （Dinoflagenate） and Its Performance in Cell Growth and Heat Stress

Harmful algal blooms （HABs） can occur and then disappear quickly, corresponding to consistent growing and declining of heavy biomasses. The molecular mechanism of blooming remains unclear. In this study, calmodulin gene （cam） of HAB causing species Alexandrium catenella was isolated and characterized, The expression of calmodulin gene was profiled at different growth rates and in heat stress. The full cDNA of cam was 597 nucleotides （nt） in length, including a 25 nt 5＇ untranslated region （UTR）, an 122nt 3＇ UTR, and a 450nt open reading frame （ORF） encoding 149 amino acids. The deduced calmodulin （CAM） was highly conserved in comparison with those of other organisms. As was determined with real-time RT PCR, the abundance of cam transcript varied in a pattern similar to cell growth rate during the whole growing period. The abundance of cam transcript increased by more than 8 folds from lag growth phase to exponential growth phase, and then obviously decreased from exponential growth phase to stationary/decline growth phase. In addition, the relative abundance of cam transcript significantly declined with time during heat shock. Taking CaM function described in other organisms into account, we believe that Ca2- -involved signal transduction, methyla- tion of DNA and toxin precursors underlined the cell growth of this species. The response of cam gene to heat stress in dinoflagellate suggested restrictions in Ca2＋ signal transduction and methylation. These findings are helpful to understand the relationships among growth, cell signal transduction, bloom formation and interaction with environmental stimuli in dinoflagellates.

Larval and Juvenile Growth Performance of Manila Clam Hybrids of Two Full-Sib Families

In order to determine whether growth performance could be improved by hybridizing full-sib families of Manila clam （Ruditapes philippinarum）, crosses between two full-sib families including self and reciprocal crosses were carried out. The effects of heterosis, combining ability and interaction on the growth of shell length were estimated. The results showed that the growth of hybrid larvae was intermediate between parents on days 6 and 9. Heterosis on shell length was observed, which varied at juvenile stage. The cross of ♂A×♀B （Hp varied between 10.41% and 68.27%） displayed larger heterosis than ♂A×♀B （Hp varied between 1.89% and 32.33%） did, suggesting that ♂A×♀B was an ideal hatchery method of improving the growth performance of Manila clam. The variances of general combining ability （GCA）, special combining ability （SCA） and interaction （I） were significant in shell length （P〈 0.05）, indicating that both additive and non-additive genetic factors were important contributors to the growth of larvae and juveniles. The GCA for shell length of ♂A×♀B was higher than that of ♂A×♀B at both larval and juvenile stages. This con- firmed that the cross between ♂A and ♀B showed great growth in shell length. In summary, the growth of Manila clam seeds could be improved by hybridizing selected parents from large numbers of full-sib families.

Strain Growth in Containment Vessels

Strain growth is a phenomenon observed in containment vessels subjected to internal blast loading. The elastic response of the vessel may become larger in a later stage compared to its response during the initial stage. The dynamic responses of infinitely long cylindrical containment vessels subjected to uniformly-distributed internal blast loading are studied using LS-DYNA. The development of bending modes and the interaction between the breathing mode and bending modes are observed. The methodology developed for dynamic elastic buckling analysis is employed to study the strain growth phenomenon in explosion containment vessels. It is shown that the dynamic instable vibration of a containment vessel is the basic mechanism of strain growth.

Longwall automation: Delivering enabling technology to achieve safer and more productive underground mining

The ongoing need to deliver improved safety, productivity and environmental benefit in coal mining presents an open challenge as well as a powerful incentive to develop new and improved solutions. This paper assesses the critical role that enabling technologies have played in the delivery of remote and automated capability for longwall mining. A brief historical account is given to highlight key technical contributions which have influenced the direction and development of present-day longwall technology. The current state of longwall automation is discussed with particular attention drawn to the technologies that enable automated capability. Outcomes are presented from an independently conducted case study that assessed the impact that CSIRO＇s LASC longwall automation research has made to the longwall mining industry in Australia. Importantly, this study reveals how uptake of this innova- tive technology has significantly benefitted coal mine productivity, improved working conditions for personnel and enhanced environmental outcomes. These benefits have been widely adopted with CSIRO automation technology being used in 60 per cent of all Australian underground operations. International deployment of the technology is also emerging. The paper concludes with future challenges and opportunities to highfight the ongoing scope for longwall automation research and development.

A retrospective clinical study of safety and efficacy of vinorelbine/epirubicin/fluorouracil(NEF) regimen as a postoperative chemotherapy for breast cancer

Objective： We aimed to investigate the safety and efficiency of vinorelbine/epirubidn/fluorouracil （NEF） regimen as adjuvant chemotherapy for breast cancer. Methods： From 2005 to 2008, 227 female breast cancer patients were treated with the NEF regimen： vinorelbine 25 mg/m^2 iv on days 1 and 8; epirubicin 60 mg/m2 iv gtt on day 1; 5-Fu 500 mg/m2 iv gtt on day 1. Chemotherapy was repeated every 21-28 days for a total of 6 cycles. Results： The major side effects were neutrope- nia and gastrointestinal syndrome, with a 5-year survival rate of 85.4%, Conclusion： NEF regimen is safe and guarantees a high survival rate which could be recommended as a adjuvant chemotherapy regimen for breast cancer,