脐橙CsNAC基因的克隆及其在果实贮藏过程中的表达分析

从脐橙(Citrus sinensis Osbeck)果皮褐变相关基因的cDNA抑制差减文库中,筛选了一个与NAC基因家族同源的EST序列,通过RACE技术成功克隆了CsNAC基因全长cDNA序列共1 203 bp,并对其进行了序列分析。结果表明,CsNAC包含一个918 bp的开放阅读框(ORF),编码305个氨基酸,预测的蛋白质分子量为35.2 kDa,等电点为6.72;CsNAC蛋白N端具有一个高度保守的NAC结构域;进化树分析表明CsNAC属于NAC蛋白家族的ATAF亚家族,可能参与胁迫反应。荧光定量PCR表达分析结果表明,CsNAC在果实贮藏过程中,随着果皮褐变的发生,与对照相比褐变果皮中的表达水平明显增强。说明CsNAC基因与脐橙果实的果皮褐变具有密切关系。     

桃叶片β- 半乳糖苷酶基因全长cDNA克隆及原核表达

 利用RT-PCR和RACE技术, 从蟠桃(Amygdalus persica var. compressa Bean) 中克隆出3 285 bp的β - 半乳糖苷酶基因cDNA全长, GenBank登录号为AY874412。该cDNA 2 559 bp, 编码853个氨基酸。将其插入到大肠杆菌表达载体pET-32a ( + ) 中, 转化BL21 trxB (DE3) , 筛选重组菌株。经IPTG诱导表达后, SDS-PAGE呈现约115 kDa特异表达条带。并通过体外酶促反应分析表达的融合蛋白的生物活性。     

中国芦荟AIDREB2基因的克隆及其胁迫表达

为了研究中国芦荟的抗逆机理,以cDNA为模板,利用3'RACE和PCR扩增方法,克隆得到了一个编码DREB蛋白的基因,命名为AlDREB2,GenBank登录号为FJ560460.其cDNA序列全长为886bp,包含一个636 bp的开放阅读框,推导编码的氨基酸序列(212个氨基酸)与库拉索芦荟AlDREBI的序列相似性很高.进化树分析结果将AlDREB2归入DREB亚家族中A-6亚组.利用RT-PCR技术分析了AlDREB2基因的表达与胁迫的关系,表明AlDREB2基因在非生物胁迫与生物胁迫中能够被不同程度诱导表达.     

延边苹果梨苯丙氨酸解氨酶基因克隆及植物表达载体的构建

以苹果梨果皮为试材,根据Genbank上已经登录的蔷薇科植物的PAL核酸序列,利用DNAStar-MegAligan软件进行多序列比对确定它们的保守区,参照西洋梨PAL序列(GenBank:DQ230992.2)设计了1对苹果梨特异的PAL引物,运用RT-PCR技术对苹果梨的苯丙氨酸解氨酶(PAL)基因进行了克隆、序列分析及分子进化方面的研究.结果表明:试验成功获得了苹果梨PAL基因的全长cDNA序列,命名为PyPAL,GenBank登录号为JQ247318.1.序列分析表明,苹果梨PAL cDNA全长2 160 bp,为完整的开放阅读框,推测其编码719个氨基酸,与鸭梨和西洋梨PAL基因的同源性均高达95％以上,所编码氨基酸序列同源性达95％以上.成功构建了含有PAL基因的重组质粒PBI121-PyPAL的植物表达栽体,转化到根瘤农杆菌LBA4404菌种中形成工程菌株,为进一步研究苹果梨果实着色调控基因及其遗传改良奠定了基础.     

独行菜LaSPS基因的克隆与生物信息学分析及原核表达

以独行菜(Lepidium apetalum)幼苗叶片为试材,采用PCR方法,扩增得到LaSPS基因的开放阅读框(open reading frame,ORF),构建pET-32a-LaSPS原核表达载体并在大肠杆菌BL21(DE3)菌株中表达LaSPS重组蛋白。结果表明:LaSPS基因ORF长1 269bp,编码422个氨基酸,包含茄呢醇焦磷酸合酶结构域,是异戊烯基合成酶家族的成员;序列分析发现,LaSPS蛋白定位于叶绿体中,不含信号肽没有跨膜区;通过序列比对和系统进化分析,显示LaSPS蛋白与拟南芥(Arabidopsis thaliana)AtSPS2蛋白相似度为91%,亲缘关系最近;在大肠杆菌BL21(DE3)菌株中成功表达LaSPS重组蛋白,为研究LaSPS基因在独行菜质体醌生物合成途径中的功能奠定了基础。     

(木奈)果实CCoAOMT与LAR基因的筛选与表达分析

以(木奈)果实为研究材料,探讨了(木奈)PsCCoAOMT和PsLAR基因在(木奈)果实不同发育时期的表达动态,采用两步法逆转录与抑制PCR技术相结合的方法构建含(木奈)果实不同发育时期的均一化全长cDNA文库,通过稀释池PCR法筛选出酚类物质代谢途径中的关键酶基因PsC-CoAOMT和PsLAR.结果表明:PsCCoAOMT和PsLAR全长cDNA序列分别为1 195 bp和1 625 bp,对应的ORF分别为744 bp和1 050 bp,分别编码247和349个氨基酸.PsCCoAOMT相对分子量为27 893.8,等电点为5.42,属于亲水性稳定蛋白;PsLAR相对分子量为38 483.1,等电点为5.40,具有亲水性,属于不稳定蛋白.同源性分析表明,PsCCoAOMT氨基酸序列与白梨相似性达96％,PsLAR氨基酸序列与蔷薇科植物高度同源.荧光定量结果表明,PsCCoAOMT在(木奈)整个生长发育过程表达量差异都不明显,整体呈下降趋势,花后50 d表达量最低;PsLAR在(木奈)整个生长发育过程表达量呈明显的下降趋势,前期高后期低,花后125 d表达量最低.     

茉莉花萜类合成酶基因JsTPS的克隆及其表达分析

以双瓣茉莉花[Jasminum sambac（L.）Ait]花瓣为材料,采用RT-PCR和RACE技术相结合的方法,克隆了萜类合成酶基因（JsTPS）的全长cDNA,该cDNA全长为1 884 bp,其中ORF为1 491 bp,编码496个氨基酸的蛋白,分子量56 989.7 D,与原核表达结果一致。序列分析结果表明,该基因编码的氨基酸序列与油橄榄（Olea europaea）的TPS2具有75%的同源性,同属于α-Farnesene synthase分支。采用荧光定量PCR技术检测JsTPS在茉莉花开放过程中的表达量变化,结果表明,表达量在未开放时（18：00）最低,在半开放时（22：00）达到最高。     

金针菇异戊烯基焦磷酸异构酶基因的克隆及表达分析

PCR扩增了金针菇(Flammulina velutipes)异戊烯基焦磷酸异构酶基因(FvIDI)的DNA全长和开放阅读框序列.该基因的ORF全长753 bp,DNA全长923 bp,含有3个内含子和4个外显子,编码250个氨基酸,金针菇异戊烯基焦磷酸异构酶相对分子质量为28450,等电点为5.05.采用实时荧光定量PCR技术研究FvIDI基因在不同发育时期和不同温度下的表达量,结果显示,FvIDI基因在采收期菌盖中表达量最高,4℃诱导处理2～4 h和37℃诱导处理2～6 h的表达量明显高于常规温度21℃处理.     

Expression of phenylalanine ammonia-lyase cDNA from rice in E. coli BL21DE3

AIM: To study the expression and its kinetics of rice phenylalanine ammonia-lyase gene encoding into E. coli as the basis of treatment for phenylketouria. METHODS: The phenylalanine ammonia-lyase-1-cDNA(rPAL-1-cDNA) from rice was recombined into E. coli high expression vector pET-28c and transformed into E. coli host strain BL21DE3. Engineering bacteria was then inducted by isopropyl-β-D-thiogalactoside (IPTG) for 1, 3, 5, 7 hours, in order to obtain high level expression. RESULTS: After induction, the expression level of fusion protein was 21.40%, 30.60%, 35.40%, 35.43% respectively. The fusion protein exhibited a band of 78.6 kD on SDS-PAGE analysis, but was not found in controls.The target protein was mainly existed in the form of inclusion body. CONCLUSION:Rice PAL gene expressing E. coli was established by gentic engineering technique.     

斑玉蕈β-葡萄糖苷酶基因的序列分析及皂苷对基因表达的影响

通过转录组测序获得了斑玉蕈(Hypsizygus marmoreus)SIEF3133菌株的β-葡萄糖苷酶基因的cDNA序列(命名为bgl1),采用荧光定量PCR检测bgl1的相对表达量。当PDB中加入0.05g/L的皂苷溶液,菌丝培养4~6d时,bgl1相对表达量降低了1/2左右(相比对照),8d开始升高,第10天为对照组的1.8倍;向工厂化生产用的栽培瓶(接种培养85d后搔菌处理)中添加0.05g/L的皂苷溶液15mL,可缩短子实体采收时间约3d(与对照组相比),在此过程中bgl1相对表达量在第5天时最低,20d时超过对照组,5d时为对照组的1.66倍。     

葡萄A病毒四川分离物的外壳蛋白基因克隆与原核表达

葡萄A病毒（Grapevine Virus A,GVA）是葡萄病毒属（Vitivirus）的典型种,在世界葡萄产区广泛分布。采集10株“藤稔”葡萄成熟枝条,使用6种葡萄病毒ELISA试剂盒检测发现10个样本中有6个感染4种不同的葡萄病毒。以GVA的ELISA阳性植株为材料进行RT-PCR扩增,首次获得了GVA四川分离物SL10的完整外壳蛋白基因（CP）。该基因全长597 bp,将其与GeneBank收录的15个GVA分离物的CP序列进行比对和构建系统进化树。把不同地理起源的GVA分离物分成2个变异组;其中Ⅰ组包括3个分离物(与Ⅱ组的其他分离物只有75.9%～80.1%的序列同一性);其余的13个分离物组成Ⅱ组（组内分离物具有84.4%～99.5%的序列同一性）。构建了GVA CP的原核表达质粒PET-30-GVAcp并转化BL21菌株,经IPTG诱导,目的基因得到了大量表达。     

芜菁二氢黄酮醇4–还原酶基因的克隆与功能鉴定

二氢黄酮醇4–还原酶（dihydroflavonol 4-reductase,DFR）是花青素生物合成晚期阶段的关键酶,属于NAD/NADP依赖型还原酶家族,催化从二氢黄酮醇转变成无色花色素苷的反应。利用UV-A处理‘津田’芜菁（‘Tsuda’turnip）和‘赤丸’芜菁（‘Yurugi Akamaru’turnip）块根24 h后提取总RNA,通过RT-PCR方法分别克隆了‘津田’芜菁BrDFR1和‘赤丸’芜菁BrDFR2基因。BrDFR1和BrDFR2的开放读码框分别为1 158 bp和999 bp,分别编码385和332个氨基酸。氨基酸序列分析显示,BrDFR1和BrDFR2与大白菜DFR具有高度同源性,从第8到第302位氨基酸的肽段具有FR_SDR_e结构域。BrDFR1和BrDFR2基因组全长序列均含有5个位置与序列完全相同的内含子。Southern杂交结果显示,‘津田’芜菁BrDFR1和‘赤丸’芜菁BrDFR2基因均为单一拷贝。UV-A可以诱导BrDFR1基因表达,对BrDFR2基因表达的诱导效果不明显。BrDFR1和BrDFR2基因在大肠杆菌细胞中可以表达并纯化出分子量约为42.8 kD的BrDFR1蛋白和37.5 kD的BrDFR2蛋白。过量表达BrDFR1和BrDFR2基因的烟草花色加深。芜菁DFR基因的RNAi载体遗传转化烟草后,转基因植株的花色变浅。这些工作将为阐明依光型和非依光型花青素生物合成机理奠定研究基础。     

Effect of 1, 2-propanediol and ethylene glycol on apoptosis of follicles in human ovarian tissue cryopreservation

AIM:To compare the effect of 1, 2-propanediol (PROH) and ethylene glycol (EG) on apoptosis and expressions of P53, Bcl-2 of follicles in human ovarian tissue, in order to offer experimental foundation for selecting the best cryoprotectant.METHODS:Biopsies of ovarian tissue obtained from 12 women were cryopreserved, and ovarian tissue slice from each woman was divided into three groups:fresh control group, ethylene glycol group and 1, 2-propanediol group.The slow-freezing /rapid-thawing protocol was used to freeze and thaw the slice of ovarian cortex.Apoptosis of follicles in fresh and frozen-thawed ovarian cortical tissue was detected by TUNEL experiment, and expressions of P53 and Bcl-2 were detected by immuno-histochemistry.RESULTS:The percentages of apoptosis follicles were 14.58%, 23.08%, 30.43% in fresh control group, PROH group and EG group, respectively, and the percentage of apoptosis follicles in EG group was higher than that in fresh control group (P<0.05), but there was no significant difference between the percentages of TUNEL positive follicles in oocytes of the three groups (P>0.05).The percentages of P53 positive follicles were 13.48%, 25.00% and 33.93%,respectively.There was significant difference between fresh control and EG group (P<0.05), and there was positive correlation between apoptosis and expression of P53 (r=0.7791, P<0.01).The percentages of Bcl-2 positive follicles were 5.29%, 3.65% and 2.41%, respectively, however, no significant difference between three groups was observed (P>0.05).CONCLUSION:The results of this study indicate that 1.5 mol/L PROH is more suitable for cryopreservation of human ovarian tissue rather than 1.5 mol/L EG in slow-freezing /rapid-thawing protocol.The protocol of slow-freezing/ rapid- thawing may preserve oocytes well, but it is not ideal for cryopreservation of granulosa cells.Cryopreservation may influence on apoptosis of follicles in human ovarian tissue.     

Prokaryotic expression of Staphylococcus aureus Panton-Valentine leukocidin and its cytolytic activities to human polymorphonuclear neutrophils

AIM:Panton-Valentine leukocidin (PVL) is a pore-forming toxin secreted by Staphylococcus aureus epidemiologically associated with the often-lethal necrotizing pneumonia. Until now, the mechanisms of pathogenesis of PVL leading to the fatal pulmonia remains undefined and also acquired plenty of the toxins is difficult. In the present study, we obtain recombinant staphylococcal F and S components of the Panton-Valentine leukocidin by gene engineering and evaluate its biological activity in vitro, which provides an experimental basis for the further studies of its biological function and its toxicity in pneumonia. METHODS:The full-length of F and S components of PVL gene amplified from the strain of Staphylococcus aureus DNA by high-fidelity PCR was cloned into prokaryotic expression vector pET22b(+), and the vector was transformed into BL21 (DE3)plysS to construct a prokaryotic expression system. The integrity of the opening-reading frame of each construct was verified by DNA sequencing. The recombinant PVL (rPVL) was induced by1.0 mmol/L IPTG. The expressed products were identified by SDS-PAGE and the fusion proteins (6His-LukS-PV and 6His-LukF-PV) were purified from lysates of transfected E. coli cells by affinity chromatography on nitrilotriacetic acid columns. The cytolytic activity was tested by incubation of rPVL with human polymorphonuclear neutrophils (PMNs) in vitro. RESULTS:The nucleotide sequence of the cloned PVL gene was the same as that of reported in GenBank. E. coli BL21 (DE3)plysS containing recombinant vectors grow at 37℃ causes some proteins to accumulate as inclusion bodies, while incubation at 30 ℃ led to a significant amount of soluble active proteins which accounted for about 31.7% of the total bacterial protein.The relative molecular weight showed on SDS-PAGE profile was consistent with the expected value which the LukS-PV protein was about 34 kD, and the LukF-PV protein was about 35 kD. The purified rPVL was obtained and its cytolytic activity to PMNs was demonstrated. CONCLUSION:The genes of lukS-PV and lukF-PV are successfully cloned into plasmid pET22b(+) and expressed in E. coli respectively, which provide a basis for analyzing the toxicity related to the diseases and further studies about the pathogenesis of PVL.     

鸭梨多酚氧化酶基因CDS区的克隆及表达

以鸭梨(Pyrus bretschneideri Rehd.)果皮基因组DNA为模板,根据已经发表的多酚氧化酶(polyphenol oxidase,PPO)基因保守序列设计引物,利用PCR技术,克隆得到鸭梨多酚氧化酶编码区序列,将此核酸序列克隆到载体pGEM-T,酶切鉴定后测序,结果表明该段序列含有1782个核苷酸,编码593个氨基酸。对鸭梨多酚氧化酶基因片段的一致性分析和进化树分析表明,该片段与沙梨(Pyrus pyrifolia,AB056680)、苹果(Malus domestica,L29450)、李(Prunuss alicina,AY866432)以及杏(Prunus armeniaca,AF020786)的一致性分别为99%、96.3%、82%和51.4%,绘制的进化树和形态学分类地位相一致。将该片段连接到表达载体pET39b上,获得的重组子命名为pET39b-PPO,热激法转化表达受体大肠杆菌BL21(DE3)菌株,用IPTG进行诱导。SDS-PAGE分析表明,PPO基因在大肠杆菌中被诱导表达蛋白质相对分子质量约66ku,检测表明具有多酚氧化酶的活性。     

Preliminary study on the recombinant plasmid pDL121 of leptospira in terrogans serovar lai and its 23 kDa antigen

AIM: To study the recombinant plasmid pDL121 and its expression product in E.coli. METHODS: pDL121 was analysed by using 6 different restriction endonucleases and dot blotting, and the isolated 23 kDa protein band was cut and injected twice into rabbits to raise anti-23 kDa serum. RESULTS: The restriction map of pDL121 was quite different from other leptospiral genes reported and digoxin labeled recombinant DNA probe of pDL121 could detect the pathogenic leptospires, whereas, not the nonpathogenic leptospires. The anti-23 kDa serum could recognize the sonicated antigen of L.interrogans serovar lai strain 017 and 23 kDa protein expressed in pDL121 and the titer of the antiserum were very high, approximately 1/12 800. Injection of the E.coli lysate of pDL121 with Freund's adjuvant into guinea pigs resulted in some protection of the animal against the challenge with strain 017. CONCLUSION: It indicated that 23 kDa protein had good imunogenicity and could serve as a candidate for protective antigen of L.interrogans and the inserted fragment of pDL121 could be a new gene .     

萝卜抗真菌蛋白基因Rs-AFPs在大肠杆菌中的表达及其转化番茄的研究

 通过基因工程手段将萝卜抗真菌蛋白基因Rs-AFP_{1( 2)} 插入大肠杆菌表达载体pTrxFus中并诱导表达, 其融合表达产物约22 kD, 约占总可溶蛋白的0. 45% ( 0. 5%) 。抑菌活性试验表明: 重组Rs-AFP_{1( 2)}有抑菌活性, 其中Rs&#1048577;AFP2 较Rs&#1048577;AFP1 抑菌活性强。构建了Rs-AFP₂ 基因的植物表达载体pBIAFP₂。利用农杆菌介导法将pBIAFP₂ 导入番茄中, 并诱导出完整的植株32 株。对其中28 株进行PCR 和PCR-Southern Blot 检测, 其中17 株呈阳性。对经PCR Southern Blot 检测呈阳性的植株进行Southern Blot 检测, 6 株呈阳性。