HaSNPV几丁质酶重组蛋白的表达、纯化和复性

棉铃虫单核衣壳核型多角体病毒（HaSNPV）是我国第一个商品病毒杀虫剂,具有使用安全、害虫不产生抗药性等优点,是一种很有发展潜力的生物农药。幼虫虫体受病毒感染后,HaSNPV几丁质酶在其液化过程中起了很大的作用,因此可以作为增效剂以显著提高细菌、病毒、真菌等微生物杀虫剂的毒力,并具有更高的安全性。将HaSNPV几丁质酶基因构建到原核表达载体pET28a中,经测序检验后转化至大肠杆菌Rosetta,然后以IPTG作为诱导剂,目标蛋白以包涵体的形式得以成功表达。在变性条件下,包涵体经镍 次氮基三乙酸(Ni-NTA)柱层析纯化,并以两种不同的方法进行复性,均可获得具有活性的HaSNPV几丁质酶。     

Bollworm responses to release of genetically modified Helicoverpa armigera nucleopolyhedroviruses in cotton

Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus (HaSNPV) has been developed as a commercial biopesticide to control the cotton bollworm, H. armigera, in China. The major limitation to a broader application of this virus has been the relative long time to incapacitate the target insect. Two HaSNPV recombinants with improved insecticidal properties were released in bollworm-infested cotton. One recombinant (HaCXW1) lacked the ecdysteroid UDP-glucosyltransferase (egt) gene and in another recombinant (HaCXW2), an insect-selective scorpion toxin (AaIT) gene replaced the egt gene. In a cotton field situation H. armigera larvae treated with either HaCXW1 or HaCXW2 were killed faster than larvae in HaSNPV-wt treated plots. Second instar H. armigera larvae, which were collected from HaCXW1 and HaCXW2 treated plots and further reared on artificial diet, showed reduced ST(50) values of 15.3 and 26.3%, respectively, as compared to larvae collected from HaSNPV-wt treated plots. The reduction in consumed leaf area of field collected larvae infected with HaCXW1 and HaCXW2 was approximated 50 and 63%, respectively, as compared to HaSNPV-wt infected larvae at 108 h after treatment. These results suggest that in a cotton field situation the recombinants will be more effective control agents of the cotton bollworm than wild-type HaSNPV.     

Comparative pathogenesis of the Helicoverpa armigera single-nucleocapsid nucleopolyhedrovirus in noctuid hosts of different susceptibility

Neonate larvae of the noctuid moth Spodoptera exigua were susceptible to an infection by Helicoverpa armigera single-nucleocapsid nucleopolyhedrovirus (HaSNPV). Biological activity (LD(50),ST(50)) of the virus was considerably reduced as compared to its activity in the homologous host, H. armigera. Pathogenesis was studied using a recombinant HaSNPV carrying a green fluorescent protein gene, which induces fluorescence in infected cells to mark infection. In larvae of H. armigera, fluorescence was pronounced in the fat body after 2.9 days post infection and could also be detected in several other tissues. In contrast, fluorescence was not observed in tissues of S. exigua until 9 days post infection and was restricted almost exclusively to cells of the ganglia. Examination of serial sections of wildtype HaSNPV-infected S. exigua-larvae revealed a similar pattern of tissue tropism. Apparently, HaSNPV does not undergo the usual steps in host invasion and infection in this insect species, but targets specifically to nervous tissue.     

一种棉铃虫多角体病毒的纯化与鉴定

对一株纯化的棉铃虫多角体病毒进行电镜观察,形态呈不规则型,直径约2 μm,命名为棉铃虫多角体-B(Helicoverpa armigera nucleocapsid nucleopolyhedrovirus-B,HaNPV-B),它对东方粘虫有较好的感染性,与棉铃虫单核型多角体病毒(Helicoverpa armigera single nucleocapsid NPV,HaSNPV)有不同的宿主域.通过半补齐法建立HaNPV-B基因组文库,拼接了一个6 035 bp的核苷酸片段,推测包含6个ORF,其包含基因内容及基因结构与HaSNPV不同,分析表明两者是不同种病毒,这为杆状病毒与宿主的相互作用及共同进化提供了信息.     

棉铃虫核型多角体病毒sod基因在大肠杆菌中的表达

用PCR方法从棉铃虫(Helicoverpa armigera)单粒包埋型核型多角体病毒(HaSNPV) C1株基因组中扩增sod基因编码区,克隆到pGEM—T—easy vector,测定了核苷酸序列。将基因编码区克隆到原核表达载体pETblue2,构建了含表达质粒pETblue2／HaSNPV SOD,转化大肠杆菌DE3 (BL21)进行IPTG诱导表达。SDS—PAGE分析表明SOD的表达量约为细胞总蛋白的37％。邻苯三酚法测定表达蛋白活性,结果表明每毫克菌体可溶性总蛋白中表达产物校正酶活力单位为694U／mg。     

棉铃虫HaTO-like基因的克隆、序列分析和表达特征

【目的】克隆和分析了棉铃虫Helicoverpa armigera HaTO-like基因的编码框序列,检测了该基因的时空表达谱以及在棉铃虫感染核型多角体病毒HaSNPV后的转录变化,为深入研究该基因的功能提供理论依据。【方法】本研究利用RT-PCR的方法首次克隆获得HaTO-like基因的全长cDNA序列,通过几种生物信息学软件对该基因的核苷酸序列和氨基酸序列进行了分析,并利用荧光定量PCR技术检测了该基因在棉铃虫不同发育阶段、幼虫组织和成虫组织的表达情况,以及HaSNPV感染对HaTO-like基因表达的影响。【结果】棉铃虫HaTO-like基因cDNA全长为994 bp,开放阅读框为756 bp,编码251个氨基酸,其蛋白序列的N端含有23个氨基酸的信号肽。进一步的序列分析表明棉铃虫HaTO-like与其他昆虫同源蛋白的氨基酸序列一致性不是太高,大概在39%~61%之间,其中与家蚕和脐橙螟在系统进化上关系最近。荧光定量PCR结果表明该基因在棉铃虫的5龄0 h和成虫第1天的的表达量相对较高,在幼虫的头部和表皮内的表达量较其他幼虫组织较高,在成虫的头部和足的表达量也相对较高。而病毒感染则显著地诱导了该基因在棉铃虫幼虫头部和表皮内的表达。【讨论】本研究克隆了棉铃虫HaTO-like基因的全长cDNA序列,分析了该基因的序列特征和表达谱,为进一步阐释该基因的功能奠定理论基础。     

AcMNPVP35抑制HaSNPV诱导的Tn-Hi5细胞凋亡

苜蓿银纹夜蛾核多角体病毒(Autographa californica multicapsid nuclear polyhedrosis virus,AcMNPV)能够抑制棉铃虫核多角体病毒(Helicoverpa armigera Nucleopoly hedrovirus,HaSNPV)诱导的Tn Hi5 细胞凋亡,并能辅助HaSNPV在Tn Hi5细胞中复制,产生具有感染能力的子代病毒。瞬时表达实验证明,在Tn Hi5细胞中,p35具有明显抑制凋亡的能力,但是不能辅助HaSNPV在Tn Hi5细胞中的复制;进一步构建超表达p35 的重组病毒:vHap35,发现vHap35能够抑制Tn Hi5细胞凋亡,但是不能产生具有感染力的病毒粒子。电镜观察发现感染重组病毒的部分细胞中存在单粒包埋的病毒粒子(ODV)。     

Efficient method to generate homologous recombinant baculovirus genomes in E. coli

Here we describe a convenient method to generate homologous recombinant baculoviral genomes in E. coli. The recombination takes place with the aid of recombination enzymes provided by the phage lambda Red system between a bacmid (a baculoviral genome that can replicate in bacteria) and a linear fragment. Proof of concept was provided when the cathepsin gene (v-cath) of the Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus (HaSNPV) was replaced by the chloramphenicol resistance gene (CmR). First, CmR was inserted between the flanking sequences of the HaS-NPV v-cath. Each of the flanking regions was about 1 kb. The fragment was linearized and electroporated into bacteria containing both the HaSNPV bacmid and the lambda Red system. Recombinant bacmids resistant to chloramphenicol were selected. In comparison to the standard co-transfection/plaque assays, this method significantly reduces the time required to construct baculovirus knockout mutants. It may also be useful in the manipulation of other large viral genomes.     

棉铃虫核多角体病毒泛素基因的克隆表达及抗体制备

昆虫杆状病毒和痘病毒是目前已知唯一编码泛素基因的病毒。通过PCR方法,克隆了棉铃虫核多角体病毒(HaSNPV)泛素基因(Ubiquitin,Ubi)。序列分析表明,该基因编码区全长252bp,编码83个氨基酸残基,预计分子量为9.24kDa。将泛素基因克隆到原核表达载体pET28a上,构建重组质粒pETUbi,转化至大肠杆菌BL21(DE3)感受态细胞中,IPTG诱导表达融合蛋白。用Histag抗体检测目的蛋白,Westenblot实验证明所表达的蛋白是带有Histag的重组融合蛋白。通过改变IPTG浓度和诱导时间对表达条件进行了优化。利用NI琼脂糖凝胶亲和层析柱纯化目的蛋白,SDSPAGE鉴定为单一条带,同时用提纯蛋白制备了特异性抗体,为进一步的研究打下基础。     

HaSNPV几丁质酶基因在大肠杆菌和昆虫细胞中的表达及其产物对Bt杀虫剂的增效作用

为了探索杆状病毒几丁质酶对微生物杀虫剂的增效作用及其利用途径 ,分别在大肠杆菌和昆虫细胞中表达棉铃虫单粒包埋型核型多角体病毒 (HaSNPV)几丁质酶 .用PCR方法扩增出不含N端信号肽编码序列的几丁质酶基因片段 ,并分别克隆至原核表达载体pET2 8a和重组到杆状病毒BactoBac表达系统 ,在大肠杆菌 (E .coli)BL2 1和粉纹夜蛾 (Trichoplusiani)细胞系Tn 5B1 4中分别进行了表达 .在大肠杆菌中表达量约占细菌总蛋白 15 % ,在昆虫细胞中表达量约占细胞总蛋白10 % .将含有几丁质酶的大肠杆菌和昆虫细胞表达产物添加到苏云金杆菌 (Bt)菌液中一起喂食 2龄家蚕 .结果显示 ,HaSNPV几丁质酶基因的 2种表达产物和Bt杀虫剂的混合物使处理的家蚕的致死时间较对照处理均明显缩短 .昆虫细胞和大肠杆菌表达产物与Bt混合物处理的LT50 分别从 93 5h和 95 1h缩短到 5 6 2h及 6 7 2h ,并且供试家蚕的生长速度明显缓慢 .研究结果表明 ,重组的HaSNPV几丁质酶有望作为Bt杀虫剂的增效剂     

中国棉铃虫核型多角体病毒不同基因型的虫体克隆

首次利用虫体克隆技术,对野生型中国棉铃虫核型多角体病毒（ＨａＳＮＰＶＷ）的不同基因型进行了分离纯化。以较低浓度的ＨａＳＮＰＶＷ感染三龄初中国棉铃虫幼虫,病毒致死幼虫单虫收集,分别提取相应的病毒核酸,进行限制性内切酶分析,得到了ＨａＳＮＰＶ的七个不同基因型（ＨａＳＮＰＶＧ１至Ｇ７）,其ＥｃｏＲＩ酶切图谱均不相同。用ＢａｍＨＩ酶切分析,七个基因型的酶切图谱只在一个片段上有显著区别：Ｇ１、Ｇ２、Ｇ３、Ｇ４ＤＮＡ的ＢａｍＨＩｈ片段大小是３．３０ｋｂ,Ｇ５、Ｇ６的这一片段的大小为３．５ｋｂ,而Ｇ７的这一片段为２．７ｋｂ。结果表明,野生型ＨａＳＮＰＶ至少包含七个不同的基因型。     

A new cell line from the embryonic tissue of Helicoverpa armigera HBN. (Lepidoptera: Noctuidae)

A new cell line from the embryonic tissue of Helicoverpa armigera was established and designated as NIV-HA-197. It was maintained in TNM-FH medium supplemented with 10% fetal bovine serum. The cell line at passage 20 had a heterogeneous population of cells consisting of mainly epithelial-like cells (70%), followed by fibroblast-like (27%), and multinucleated giant (3%) cells. The chromosome number ranged from 45 to 185. The growth curve at passage 40 showed a fivefold increase in cell number with a population-doubling time of approximately 60 h. The cell line was found infected with the microsporidium Nosema heliothids at passage 9. Using the antiprotozoan drug Metrogyl 400 and simultaneous heat treatment, the parasite was removed from the culture. The cell line can be cryopreserved for 30 mo. The species specificity of the new cell line was determined by studying the isoenzyme profile of four enzymes, viz., lactate dehydrogenase, malate dehydrogenase, isocitrate dehydrogenase, and glucose 6-phosphate dehydrogenase, and by heteroduplex analysis. Heteroduplex analysis was used to analyze the mitochondrial 16S ribosomal ribonucleic acid gene sequences along with the host insect gene sequences, and 100% homology was obtained, confirming the conspecificity of the cell line. The cell line was found to be susceptible to the baculoviruses Autographa californica multiple nucleopolyhedrovirus, Spodoptera litura multiple nucleopolyhedrovirus, and H. armigera single nucleopolyhedrovirus (HaSNPV). More than 90% of the cells were infected by HaSNPV on the seventh post infection day (PID), and 28.8 x 10(6) NPV/ml was yielded on the 10th PID. The in vitro-grown HaSNPV caused 100% mortality, when fed to the second instar H. armigera larvae, in 6 d. Cessation of feeding was observed on the second PID.     

中国棉铃虫单粒包埋核多角体病毒（HaSNPV）HindⅢ-Ⅰ片段的序列分析与基因排列研究

对中国棉铃虫单粒包埋核多角体病毒（HaSNPV)基因组中的HindⅢ-Ⅰ片段的序列进行分析,该片段全长7501nt,包括10个开放阅读框：AcMNPV ORF111的同源基因（Ac 111),晚期表达因子2（lef-2）基因,病毒核壳结构蛋白p24基因、gp16基因、多角体包膜蛋白（polyhedron envelope protein,pep)基因、AcMNPV ORF63的同源基因（Ac63),38.7kD基因,晚期表达因子1（lef-1) 基因,及两个特有基因HaSNPV orf591和HasSNPV orf435。基因组的排列比较分析发现与AcMNPV有较大区别。     

SeMNPV抑制HaSNPV诱导的Se—UCR细胞凋亡

在采用共感染和共转染的方法构建扩大杀虫范围的重组病毒的研究过程中发现棉铃虫单核衣壳核多角体病毒(Helicoverpa armigera single nucleocapsid nucleopolyhedrovirus,HaSNPV)能诱导甜菜夜蛾细胞,Se-UCR发生典型凋亡,但不能诱导另一株甜菜夜蛾细胞Se-301产生凋亡。以5MOI的HaSNPV感染Se-UCR。在12h左右可以观测到少量细胞凋亡。24h能观察到明显的凋亡,凋亡细胞数量随时间不断增加,到72h基本上所有的细胞均发生凋亡,成为凋亡小体,基因组DNA片段化。同时发现HaSNPV诱导的甜菜夜蛾Se-UCR细胞凋亡能够被甜菜夜蛾多核衣壳核多角体病毒(Spodoptera exigua multicapsid nucleoplyhedrovirus,SeMNPV)所抑制,进一步点杂交试验发现SeMNPV和HaSNPV共同感染Se-UCR获得了HaSNPV在该细胞中的复制。     

棉铃虫单核衣壳核多角体病毒(HaSNPV)Hind III-L片段的序列分析

本文报道了棉铃虫单核衣壳核多角体病毒 (Helicoverpaarmigerasingle nucleocapsidnucleopolyhedrovirus,HaSNPV)基因组的HindIII L片段的全序列。该片段全长 2 6 35bp ,包括 5个有意义的开放阅读框 :HaSNPVORF2 2 7,晚期表达因子 10基因 (lef10 ) ,vp10 5 4基因 ,Ac5 5 (AcMNPVORF5 5的同源基因 ) ,Ac5 6 (AcMNPVORF5 6的同源基因 )。与其它 6种杆状病毒的氨基酸序列比较表明 ,HaSNPV的lef10基因与甜菜夜蛾核型多角体病毒 (SeMNPV)的同源性最高 ,为6 4 % ,与冷杉毒蛾核型多角体病毒 (OpMNPV)的同源性最低 ,为 4 3% ;HaSNPV的vp10 5 4基因与SeMNPV的同源性最高 ,为 6 5 % ,与OpMNPV的同源性最低 ,为 4 9%。序列比较表明 ,HaSNPV的LEF10与VP10 5 4蛋白与其它 6种杆状病毒具有相同的保守区和亮氨酸拉链 (leucinezipper)     

重组棉铃虫病毒的外源基因向其他生物的转移

本文报道了基因工程棉铃虫核多角体病毒(HaSNPV-AaIT)的外源蝎子毒素基因(AaIT)是否会向环境中的植物病原微生物或捕食性天敌转移的实验结果。首先,于实验室内将重组病毒HaSNPV-AaIT与棉花黄萎病病菌(VerticilliumdahliaeLleb.)进行了长达90d的混合培养,在混合培养30d,60d和90d后分别提取棉花黄萎病病菌的基因组DNA,用AaIT基因作探针进行点杂交,结果显示无阳性信号。另外,从多次施用过重组病毒的棉花田中采集了120只龟纹瓢虫和七星瓢虫,利用健康蚜虫饲养3-4d,用碱解液处理瓢虫体表后,从处理液中可以检测到病毒DNA;但瓢虫体表经碱解液和Dnase处理后,从瓢虫体内提取的基因组DNA,用PCR和斑点杂交的方法,都没有检测到AaIT的序列存在。本研究的实验结果说明,基因工程病毒的外源基因向其它生物转移的可能性极低。     

Kinetic characterization of the group II Helicoverpa armigera nucleopolyhedrovirus propagated in suspension cell cultures: implications for development of a biopesticides production process

Large-scale commercialization of baculovirus biopesticides for the control of insect pests requires a cell culture production process, and knowledge of the infection kinetics is a vital prerequisite for process optimization. Well-characterized kinetic parameters have so far only been reported for the commercially established recombinant Autographa californica nucleopolyhedrovirus (AcMNPV), a Group I NPV. In this work, key infection kinetic parameters of the Group II NPV Helicoverpa armigera nucleopolyhedrovirus (HaSNPV), and its Few Polyhedra (FP) mutant, were well characterized for the first time, in suspension HzAM1 insect cell cultures, to facilitate the scale-up of an HaSNPV-based biopesticide. The FP mutant had a selective advantage over wild-type HaSNPV in cell cultures, and the kinetic analysis showed that this was due to a superior budding rate, rather than a faster binding rate (BR) or longer budding duration. Another finding was that wild-type HaSNPV had very poor infection kinetics when compared with AcMNPV, exhibiting an 18-fold lower BR, a more than 50-fold lower budding rate, and a 60-fold lower extracellular/total progeny virus ratio. Such poor infection kinetics have serious implications during scale-up of an HaSNPV biopesticide production process, including the requirement for large volumes of virus inocula and the difficulty of achieving synchronous infections. Groups I and II NPVs may have very different infection kinetics because of their different envelope fusion proteins. This study is the first to compare the two groups of NPVs in terms of well-characterized cell-specific infection kinetics, and the findings may indicate a phylogenetic basis for kinetic differences.     

棉铃虫单粒包埋型核型多角体病毒极早期基因(ie-1)分析(英文)

克隆了棉铃虫Helicoverpaarmigera单粒包埋型核型多角体病毒 (HaSNPV)C1株基因组DNA ,并通过随机测序的方法测定了经XbaI酶切后的H片段的核苷酸全序列。序列比较和分析发现该片段中ORF1 3与苜蓿丫纹夜蛾Autographacalifornica多粒包埋型核型多角体病毒 (AcMNPV)基因组ORF1 47(ie 1 )同源。ie 1基因编码区全长 1 986bp ,根据推测的氨基酸序列 ,可编码 6 6 1个氨基酸残基组成的多肽 ,预计分子量为 76 .5kD。将所推导的HaSNPVIE 1氨基酸序列与其它已知的杆状病毒IE 1氨基酸序列进行比较 ,结果表明 ,HaSNPV和谷实夜蛾H .zea单粒包埋型核型多角体病毒IE 1氨基酸序列最为相似 ,同源性高达 98%。与AcMNPV、家蚕Bombyxmori核型多角体病毒 (BmNPV)、云杉卷叶蛾Choristoneurafu miferana多粒包埋型核型多角体病毒 (CfMNPV)、舞毒蛾Lymantriadispar多粒包埋型核型多角体病毒(LdMNPV)、黄杉毒蛾Orgyiapseudotsugata多粒包埋型核型多角体病毒 (OpMNPV)、甜菜夜蛾Spodopteraex igua多粒包埋型核型多角体病毒 (SeMNPV)、小菜蛾Plutellaxylostella颗粒体病毒 (PxGV)和Xestiac ni grum颗粒体病毒 (XcGV)的IE 1氨基酸序列同源性较低 ,分别为 2 3 %、2 3 %、2 3 %、2 5 %、2 3 %、1 4%、2 7%和 7%。根据氨基酸序列由GENETYX     

Serial passage of a Helicoverpa armigera nucleopolyhedrovirus in Helicoverpa zea cell cultures

The serial passaging of baculoviruses in cell lines numerous times can result in a variety of mutations or defective viral populations becoming predominant in the cultures. The generation of these mutants during cell culture passage, also known as "the passage effect," can seriously hinder the use of in vitro methods for large-scale production of baculoviruses for use as biopesticides. In an effort to develop a large-scale in vitro method of producing Helicoverpa armigera singly enveloped nucleopolyhedrovirus (HaSNPV), it was essential to determine whether or not the passage effect was evident when this virus is serially passaged in cell cultures. An isolate of HaSNPV was serially passaged in Helicoverpa zea cell cultures up to 10 times. The production of occlusion bodies decreased with increasing passage number and there was evidence of defective viruses becoming predominant in cultures after 5 passages. The number of virions present within cross sections of passage 3 occlusion bodies was 1.5 times higher than those from passage 10 occlusion bodies when quantified using electron microscopy. A laboratory bioassay showed that potencies of passage 3 isolates against H. armigera larvae were 8 times higher than potencies of passage 10 isolates. This study indicated that changes typical of the passage effect were evident when HaSNPV was serially passaged in H. zea cell cultures up to 10 times.