柑桔钙离子结合蛋白基因克隆及植物表达载体构建

以伏令夏橙叶片中分离的总RNA为模板,经RT-PCR扩增到一条约600bp、含钙离子结合蛋白基因(CsCaBP)的片段,将此片段克隆到pMD-19T中,经测序分析该片段与甜橙基因组中的对应序列完全吻合。设计2对带有限制性内切酶位点的特异性引物,以cDNA为模板扩增到2个CsCaBP片段,并连接到TA克隆载体pMD-19T上;经双酶切消化后,分别以正反2个方向插入到植物表达载体pFGC5941的查耳酮合成酶(CHSA)内含子两侧,构建成功CsCaBP的RNA干扰载体,但未获得转基因植株。将CsCaBP的正向片段定向克隆到具有CaMV35S启动子的pF-GC5941表达质粒上,构建成功CsCaBP过量表达载体。将构建好的表达载体导入根癌农杆菌LBA4404菌株,转化酸橙下胚轴,经PCR检测,获得9株过量表达转基因植株,荧光定量PCR验证发现目的基因在转基因植株中有不同程度的表达。     

韧皮部特异启动子驱动密码子优化的抗菌肽D基因的植物表达载体构建

根据177个GenBank中登录的柑橘编码蛋白密码子用法的分析结果,优化并重新设计和合成了含柑橘偏爱密码子、对柑橘黄龙病有杀灭作用的柞蚕抗菌肽D基因(命名为CAPD),克隆入pUC19克隆载体并经测序验证后,获得了含新抗病基因的重组质粒pUC19-CAPD。用限制性内切酶BamHI和SacI双酶切pUC19-CAPD克隆载体和pBI121植物表达载体的质粒DNA,回收pUC19-CAPD克隆载体中的CAPD基因小片段和pBI121植物表达载体中去掉GUS报告基因的大片段,经连接、转化和鉴定后,构建了由CaMV35S组成型启动子(35SP)驱动CAPD目的基因的新植物表达载体(命名为pHZ05);用限制性内切酶BamHI和HindIII双酶切含笋瓜韧皮部特异启动子(PSP)的pUCm-PSP克隆载体和pHZ05植物表达载体的质粒DNA,分别回收pUCm-PSP克隆载体中的PSP小片段和pHZ05植物表达载体中去掉CAPD目的基因上游35SP的大片段,经连接、转化和鉴定后,构建了由PSP驱动CAPD目的基因的新植物表达载体(命名为pHZ06)。利用细胞感受态法直接将2个由不同启动子驱动的含CAPD目的基因的新重组植物表达载体分别导入根癌农杆菌LBA4404、GV3101、EHA105和发根农杆菌Ri15834等4个农杆菌菌株中,为利用农杆菌介导的遗传转化技术培育抵抗由韧皮部传导的毁灭性和检疫性病害柑橘黄龙病的新种质奠定了基础。     

沙地葡萄茎痘相关病毒RT-PCR检测

为建立快速、灵敏、可靠的沙地葡萄茎痘相关病毒(GRSPaV)检测方法,以总RNA为模板,采用2组GRSPaV特异性引物对29个品种52株葡萄样品进行RT-PCR检测,并对扩增产物进行了测序和分析。结果表明,从20个品种25株葡萄样品中检测到GRSPaV,平均带毒株率为48.1%。外壳蛋白基因片段引物F1/R1从25个样品中扩增到905bp的特异片段,复制酶基因片段引物F2/R2从20个样品中扩增到498bp的特异片段,表明GRSPaV外壳蛋白基因比复制酶基因更加保守,RT-PCR检测时采用F1/R1则更为适宜。PCR产物测序结果与GenBank中登录的GRSPaV序列比较,同源性为97.90%～98.11%。     

GAPB基因原核表达载体的构建

以拟南芥cDNA为模板,用PCR扩增出GAPB的基因全长,然后将GAPB基因片段连接到PET28a（＋）载体上,构建重组质粒并转化大肠杆菌DH5α,经菌落PCR和酶切鉴定筛选出阳性克隆,测序正确后,再将阳性克隆的质粒转化大肠杆菌BL21（DE3）。结果表明：成功构建了原核表达载体PET28a（＋）-GAPB,为后续的G...     

拟南芥花期基因FT转化切花菊‘神马’

采用RT-PCR方法从拟南芥叶片中克隆FT基因,经过测序分析、酶切之后,连接到植物表达载体Super1300+,构建植物重组载体FT-Super 1300+,运用农杆菌介导法将FT基因导入切花菊'神马'中,鉴定其在转化植株体内的整合和表达.扩增得到的基因片段经测序分析与GenBbank上的FT基因同源性为100%;构建的植物表达载体经过酶切分析证实外源基因已经正确插入;转化后得到了29株抗性植株,PCR和PCR-Southern杂交结果显示,8株抗性植株为阳性,说明外源基因整合到转化植株的基因组中.RT-PCR鉴定结果表明外源基因在转化植株叶片中表达.其中转FT基因的一个株系在组培条件下分化出花芽,表明转基因植株花芽分化不受光周期影响,花期可以提前.     

PRK基因原核表达质粒的构建

以拟南芥cDNA为模板,扩增出PRK基因,构建重组质粒pET-28a（＋）-PRK转化大肠杆菌DH5α。经PCR鉴定和酶切鉴定筛选出阳性克隆,将阳性克隆的质粒转化到大肠杆菌表达载体BL21中,构建PRK基因原核表达载体。测序结果表明pET-28a（＋）-PRK载体构建成功。     

甜瓜蔗糖磷酸合成酶基因全克隆及工程载体的构建

蔗糖磷酸合成酶在甜瓜果实蔗糖合成途径中起关键性的调节作用,克隆该基因并导入甜瓜低糖自交系,可改良甜瓜果实品质创新优良种质。从甜瓜幼苗叶片提取总RNA,利用RT-PCR与Southern blot方法相结合,重组子质粒经限制性内切酶酶切和PCR验证以及测序同源性比较,克隆到基因的5’(2859bp)和3’(852bp)。应用高保真Taq聚合酶PCR拼接蔗糖磷酸合成酶完整cDNA序列3692bp,该片段与GenBank中其它植物基因序列具有97%￣99%的同源性,登录号DQ364058。应用BamHⅠ、KpnⅠ、BglⅡ限制性酶切获得植物双元表达载体pROK2及基因的线性片段,通过T4连接酶反应,构建了以CaMV35S为启动子,以Tnos为终止子的工程载体pROK-SPS,该载体含有Npt-II选择标记基因。     

拟南芥花期基因FT 转化切花菊‘神马’

 采用RT-PCR 方法从拟南芥叶片中克隆FT 基因,经过测序分析、酶切之后,连接到植物表达载体Super1300⁺,构建植物重组载体FT- Super1300⁺,运用农杆菌介导法将FT 基因导入切花菊‘神马’中,鉴定其在转化植株体内的整合和表达。扩增得到的基因片段经测序分析与GenBbank 上的FT 基因同源性为100%;构建的植物表达载体经过酶切分析证实外源基因已经正确插入;转化后得到了29 株抗性植株,PCR 和PCR-Southern 杂交结果显示,8 株抗性植株为阳性,说明外源基因整合到转化植株的基因组中。RT-PCR 鉴定结果表明外源基因在转化植株叶片中表达。其中转FT 基因的一个株系在组培条件下分化出花芽,表明转基因植株花芽分化不受光周期影响,可以提前花期。     

刺激植物响应蛋白基因TatEpl1的克隆及原核表达载体构建

以深绿木霉(Trichoderma atroviride)ACCC30153为试材,采用PCR技术克隆到刺激植物响应蛋白基因TatEpl1,并构建TatEpl1的原核表达载体。结果表明:经测序得到的cDNA和DNA序列长度分别为417bp和487bp,接受号分别为JN695780和JN695781。以cDNA为模板进行PCR获得TatEpl1基因片段,并将目的片段插入原核表达载体pGEX-4T-2的相应位置,获得重组表达载体pGEX-TatEpl1,并将其转入大肠杆菌(Escherichia coli)BL21中获得重组菌株BL21-TatEpl1,经检测均呈阳性。     

基于In-fusion技术的ERECTA基因植物表达载体的构建

以黄瓜品种‘长春密刺’(CCMC)为试材,利用高保真酶Iproof及不依赖于酶切的In-fusion技术,构建基于本底启动子驱动的黄瓜ERECTA基因的植物表达载体,以探讨ERECTA基因在黄瓜中的功能,以期为黄瓜抗性性状的遗传改良提供技术支持。结果表明:从CCMC的基因组DNA中克隆的2段gERECTA(DNA序列)长度分别为8 940bp和9 812bp,并分别命名为CsgERECTA-Flag和CsgERECTA-Poly。经过质粒PCR、梯度片段PCR和测序结果的鉴定表明,pCAMBIA3301-gERECTA的2个植物表达载体都已成功构建并转入根癌农杆菌EHA105中。     

小金海棠MxIRT1基因定点突变的研究

采用PCR技术对小金海棠MxIRT1基因的定点突变体系进行了探讨。根据MxIRT1开放阅读框（ORF）两端和突变位点序列各设计一对引物。通过PCR扩增,获得带有突变位点且在突变位点相互重叠的两个PCR片段。对以上两个片段的浓度进行调整后,将其用作PCR反应的模板。对退火温度和延伸时间进行优化后,利用ORF两端引物,将带有突变位点的两个片段拼接起来,从而获得了含有所要突变位点的MxIRT1,并将其插入pEASY-T2载体中。DNA序列分析表明在预期位点上已经发生了突变：MxIRT1编码的第186位密码子已由组氨基酸残基变为丙氨酸残基,证明用PCR技术已成功地突变了MxIRT1基因。整个突变过程不需要任何回收与纯化步骤,是一个高效、快捷的定点突变体系。     

应用多重RT2PCR检测百合无症病毒和百合斑驳病毒

 根据病毒外壳蛋白基因序列, 设计了2对检测百合无症病毒(LSV) 、百合斑驳病毒(LMoV)的引物, 对扩增条件进行优化, 建立了同时检测LSV和LMoV的多重RT-PCR检测方法。此方法可特异地从带有LSV和LMoV的样品中扩增出2条带LSV (876 bp) 、LMoV (662 bp)。灵敏性测定结果表明, 该双重PCR可从稀释10⁴ 组织中检测出病毒, 具有与单一PCR相同的灵敏性。扩增产物测序表明, LSV扩增产物与其它分离物核苷酸同源性为87.8%～99.3%, LMoV扩增产物与其它分离物的同源性为90.1%～99.5%。     

类黄酮3',5'羟基化酶基因的克隆及转化铁炮百合

 利用RT-PCR技术从矮牵牛的紫色花瓣中克隆了两个控制花色的类黄酮3',5'羟基化酶基因Hf 1和Hf 2, 并构建了植物表达载体, 利用农杆菌介导法对铁炮百合进行了遗传转化, 获得了转基因植株。     

草菇丝/苏氨酸蛋白激酶同源基因的克隆及序列分析

根据担子菌丝/苏氨酸蛋白激酶同源基因编码的氨基酸序列设计两对简并引物,通过巢式简并PCR方法获得草菇(Volvariella volvacea)丝/苏氨酸蛋白激酶同源基因(vv-stpk1)的保守片段,然后通过基因组步行的方法获得了vv-stpk1全长序列。vv-stpk1全长为2 003 bp,含有8个内含子,长度分别为72、57、53、54、45、50、55和48 bp,可编码522个氨基酸残基的多肽。推定的氨基酸序列与玉米黑粉菌(Ustilagomaydis)、木糖发酵酵母(Pichia stipitis)、新型隐球菌(Cryptococcus neoformans)中与细胞形态发生相关的丝/苏氨酸蛋白激酶Orb6的相似性分别为81%、77%和76%,对VV-STPK1蛋白的系统发生学分析的结果表明,VV-STPK1与Orb6同源蛋白聚在同一进化枝上,这些数据都支持VV-STPK1蛋白为与细胞形态发生相关同源蛋白的推定。     

油桃保护地栽培整形修剪方式研究

连续3年在保护地高密（610株·667m(－2)）栽培条件下，对‘曙光’油桃两种整形方式和“采后去冠”（PostharvestCanopyRemoval，简写作PCR）修剪系统进行了研究。结果表明：（1）与传统的低干开心形相比，圆柱形整枝有利于形成较大面积的叶幕和较大体积的树冠，而且树冠疏松，冠内透光率高。2年生树产量2104．5kg·666．7m(-2)，比低于开心形高39．1％，3年生材产量达2318．0km·667m(－2)，比开心形高35．3％，且成熟期提早3～4d，外观及内在品质也较好。（2）PCR修剪后60～70d可再生新的树冠，然后，通过喷施PP333和控水、控氮、增磷等综合措施可形成大量饱满花芽。圆柱形整形结合PCR修剪可有效地控势、控冠，促进保护地密植栽培早产、稳产。     

Effects of gonadotropin-releasing hormone analogue on sensitivity of breast cancer cells to 5-FU and epirubicin in vitro

AIM: To investigate whether gonadotropin-releasing hormone analogue (GnRHa) affect the sensitivity of breast cancer cells to 5-FU and epirubicin in vitro. METHODS: Two breast cancer cell lines (MCF-7 and MDA- MB-231) were treated with different concentrations of GnRH analogue, triptorelin acetate, or with a GnRHa+5-FU or GnRHa+epirubicin. The cellular growth profiles were determined by CCK-8. The mRNA levels of GnRH receptor, PCNA and MDR1 were measured by RT - PCR. RESULTS: Both cell lines had positive GnRH receptor mRNA expression detected by RT- PCR. GnRHa did not suppress cell growth after GnRHa exposure. IC50 of 5-FU and epirubicin was not changed in the presence of GnRHa. Suppression of cell growth by the exposure to 5-FU and epirubicin was not changed in the presence of GnRHa. GnRHa treatment up-regulated PCNA mRNA expression in MDA-MB-231 cells but not in MCF-7 cells. The expression of MDR1 mRNA was down-regulated by GnRHa in MCF-7 cell lines. No MDR1 mRNA expression in MDA-MB-231 cells was observed. CONCLUSION: The present data suggest that GnRH analogue (triptorelin acetate) does not affect the sensitivity of breast cancer cell lines MCF-7 and MDA-MB-231 to 5-FU and epirubicin. GnRHa may decrease the drug resistance by down-regulating MDR1 mRNA expression.     

Construction of recombinant retrovirus vector carrying hTERT and transfected to MSCs in human cord blood

AIM:To construct a recombinant retrovirus vector carrying hTERT for establishing UCBMSCs with hTERT (hTERT-MSCs) to overcome their limited life span and detecting whether telomerized UCBMSCs line maintained long-term self-renewal and differentiation capacity. METHODS:The whole cDNA was generated by PCR amplifications from the plasmid pEGFP-hTERT-C1. The hTERT segments were subcloned into pLNCX2. The target cells were infected with these retroviral particles. The stably transfected cells were selected by neomycin and expanded life span which were designated hTERT-MSCs was observed. The expression of hTERT in mRNA level was detected by RT-PCR and the telomerase activity was measured by TRAP (PCR)-ELISA assay. The hTERT-MSCs were induced with 5-azacytidine to cardiac muscle cells and the specific marker of myocardiocyte was detected. RESULTS:The constructed plasmids were digested with restriction endonucleases (BglⅡand NotⅠ). Two characteristic segments including 6.1 kb and 3.6 kb were obtained. The hTERT-MSCs expressed hTERT in mRNA level. The telomerase activity of hTERT-MSCs was positive. The growth kinetics of hTERT-MSCs was higher than those in UCBMSCs. The hTERT-MSCs were induced to myocardiocyte. CONCLUSION:The hTERT recombinant retrovirus vector has been successfully constructed. The hTERT gene activates the telomerase and prolongs the life-span of cells. No effect of hTERT gene on some type of differentiation potential of MSCs is present.     

Changes of DNA methylation at CpG sites in promoter region of TNF-α gene in DENV2-infected peripheral blood mononuclear cells

AIM：To examine DNA methylation at CpG sites in the promoter region of tumor necrosis factor-alpha (TNF-α) gene in dengue virus type 2 (DENV2)-infected peripheral blood mononuclear cells (PBMC).
METHODS：DNA methylation in the promoter region of TNF-α gene was measured by bisulfite sequencing PCR.
RESULTS：The promoter region of TNF-α gene was from -294 bp to +58 bp, including 11 CpG sites. The PCR products identified by aga-rose gel electrophoresis were consistent with the theoretical size. Two sites were methylated at 0 h and 6 h and 6 sites were methylated at 12 h in TNF-α gene promoter region in DENV2-infected PBMC. The average methylation rates were 103%, 121% and 255% at 0 h, 6 h and 12 h, respectively. Significant differences between 0 h and 12 h and between 6 h and 12 h were observed.
CONCLUSION：The DNA methylation in the promoter region of TNF-α gene is increased in DENV2-infected PBMCs.