草莓镶脉病毒的PCR检测及特异片段的序列分析

用CTAB法从感病的草莓叶片中提取总DNA,以其为模板经PCR扩增获得与预期片段大小一致长约600bp的扩增产物,同时优化PCR反应程序,获得单一特异条带;通过总DNA浓度梯度稀释,进行PCR扩增,结果表明能检测到2.5μg叶组织中病毒的存在。回收PCR特异扩增产物,与pMD18-T载体连接,并进行转化、重组克隆的筛选、重组质粒的酶切鉴定和序列测定。扩增片段序列与已报道SVBVCP基因序列(序列号:Nc_001725)的核苷酸同源性为89.2%,氨基酸同源性为96.3%。该特异片段序列在GenBank中的登记号为AY862389。     

人胰岛素基因的人工合成及转化银耳的研究

用PCR法合成人胰岛素基因,克隆到pUC18载体上,经测序证实其碱基序列与人胰岛素基因的序列完全一致。本实验还构建了银耳表达载体,由限制性内切酶介导(Restriction enzy me-mediated DNA Integration,REMI)转化银耳芽孢。随机挑取21个抗性菌落,转管繁殖2代后检测其GUS活性,实验结果:18个菌株阳性,3个菌株阴性。从这21个菌株中选取10个菌株,提取染色体DNA,用人胰岛素基因、GUS基因和Tnos序列的特异引物进行PCR,结果表明,这10菌株都能扩增出相应长度的特异片段,证明了它们是人胰岛素基因转化子。     

柚木虱体内韧皮部杆菌亚洲种多基因位点的分子鉴定

利用与柑桔黄龙病相关的韧皮部杆菌("Candidatus Liberibacter sp.",简称Ca.L.sp.)16SrDNA基因、β-操纵子核糖体蛋白基因、外膜蛋白基因以及16S-23SrRNA间隔转录区基因位点的4对特异性引物,对采自云南瑞丽柠檬园的柚木虱(Psylla citrisuga)DNA样品进行PCR扩增,将扩增产物进行纯化、回收,连接至PEASY-T3载体并转化大肠杆菌感受态细胞Trans1-T1,筛选阳性克隆进行测序,利用NCBI Blastn软件以及MEGA5.05软件对所克隆的序列进行同源性分析与聚类分析。结果表明:柚木虱体内韧皮部杆菌亚洲种在这4个基因位点与已报道的Ca.L.asiaticus psy62株系全基因组相应基因位点的同源率均为99%。本研究证实柚木虱能够携带韧皮部杆菌亚洲种,是该菌新的昆虫宿主。     

CRISPR/Cas9技术在天目地黄RcPDS1基因编辑中的应用

为了研究CRISPR/Cas9技术在天目地黄基因编辑中的应用，克隆了天目地黄（Rehmannia chingii）的八氢番茄红素脱氢酶基因（Rc PDS1），利用PCR方法扩增其c DNA序列和基因组DNA序列。通过构建单靶点CRISPR/Cas9载体，利用根癌农杆菌介导的遗传转化方法侵染天目地黄无菌苗叶盘，通过TA克隆测序法分析基因编辑的类型。结果显示，克隆获得了1个天目地黄Rc PDS1的全长c DNA序列，其具有1个长度为1 743 bp的开放阅读框，编码580个氨基酸残基，基因组DNA序列长度8 041 bp，包含14个内含子和15个外显子。通过遗传转化共获得57个转基因再生株系，其中具明显白化表型的株系有20个（35.09%）。TA克隆测序结果显示，Rc PDS1靶位点突变类型主要包括碱基缺失、替换和插入。利用CRISPR/Cas9基因编辑技术在天目地黄中成功实现了对Rc PDS1基因的靶向敲除。     

杧果查尔酮合成酶基因(CHS1)的克隆与表达分析

【目的】克隆鉴定杧果CHS基因,分析其功能,明确杧果不同组织器官中CHS基因表达情况。【方法】以海南种植的6个杧果种的叶片总DNA和c DNA为模板,进行同源性PCR扩增,然后克隆到p MD18-T载体上,进行测序;通过生物学软件预测分析CHS基因编码的蛋白质;运用半定量PCR分析CHS基因表达情况。【结果】测序得到6个杧果种CHS基因c DNA全长为1 173 bp,CHS基因含有2个外显子和1个内含子。基于c DNA序列的NJ系统发育树显示,其与普通杧果(Mangifera indica)CHS1基因同源性最高。CHS1基因半定量表达显示杧果不同器官均表达CHS1基因,但在叶片和花中的表达量较高。【结论】克隆了杧果查尔酮合成酶1(CHS1)基因,半定量分析了杧果不同器官中CHS1基因的表达差异,为下一步研究提高CHS1基因的表达量奠定了基础。     

君子兰转化酶基因片段(CMCW1)的克隆和序列分析

 分析植物酸性转化酶基因的保守区序列，设计一对PCR引物，以君子兰基因组DNA为模板，采用PCR方法扩增出长约500 bp的DNA片段，克隆入pGEM-TEasy载体，测序结果表明获得君子兰酸性转化酶基因家族的一个成员CMCW1，该基因片段长518 bp，不含内含子，编码172个氨基酸。其序列已在GenBank中登记(登记号为AY151269)。在GenBank中进行同源性检索的结果表明，该成员编码的氨基酸与其它植物细胞壁酸性转化酶编码的氨基酸同源性较高。     

应用IC-RT-PCR方法检测水仙中百合斑驳病毒

水仙病毒严重影响水仙的品质与规模化生产,而快速检测水仙病毒可以有效防控其危害与扩散。根据已报道的百合斑驳病毒外壳蛋白基因序列设计PCR引物,利用免疫捕获PCR检测了水仙样品中百合斑驳病毒。PCR扩增产物回收后克隆到PMD19-T载体中测序。把克隆得到的百合斑驳病毒外壳蛋白基因部分序列提交到Genbank中。结果表明:基因登录号为JF714974,克隆的百合斑驳病毒外壳蛋白基因部分序列与国内外百合斑驳病毒同源性为90.4%~99.5%。建立了水仙中百合斑驳病毒的IC-RT-PCR的检测方法,简化了试验步骤,适合于水仙中百合斑驳病毒的快速检测。     

利用PCR技术检测草莓镶脉病毒

 采用特异引物的PCR 扩增方法, 对30 个草莓品种进行了草莓镶脉病毒的检测, 同时用指示植物小叶嫁接法对被检植株进行了病毒检测, 两种方法结果一致。回收、克隆PCR 扩增出的特异DNA 片段,获得了携有草莓镶脉病毒CP 基因片段的载体。测序结果表明, 得到的特异DNA 片段同美国草莓镶脉病毒的株系ATCC 45058 CP 基因片段相比, 同源性为90. 94 %。     

大白菜开花相关基因FLC1的BAC克隆筛选及分析

采用改良的混合池构建方法构建大白菜BAC文库一级混合池和二级混合池,利用开花相关基因FLC1特异引物对其进行PCR筛选。通过三步PCR扩增、114个PCR反应,筛选了19 200个克隆,获得了2个FLC1单克隆。克隆测序结果表明,其扩增产物的序列与大白菜FLC1的相似性达到99%,证实此克隆为含FLC1基因的BAC克隆。     

菠菜NBS-LRR类抗病基因同源序列的克隆及分析

依据已知NBS-LRR类抗病基因的P-loop和GLPL两个保守结构域设计简并引物,对抗菠菜霜霉病商业杂交种RZ51-147、自交系12S3和12S4的基因组DNA进行PCR扩增、克隆和序列测定,共获得23条具有完整开放阅读框且含有NBS结构的抗病基因同源序列(resistancegeneanalogs,RGAs),编号为SP1~SP17、SP19~SP24,其在NCBI中的登录号为KX914865~KX914887。核苷酸比较分析结果表明,这23条RGAs大多与甜菜中推测的一些抗病蛋白基因或其他相关蛋白基因具有较高的同源性,其中SP1、SP2、SP5、SP6、SP10、SP11、SP12、SP13等8条序列均与甜菜RF45类抗病蛋白有着86%以上的同源性;SP3、SP4、SP8、SP9、SP24等5条序列与甜菜RPP13类抗病蛋白的同源性在85%以上,与向日葵抗霜霉病基因PI8相应区域的氨基酸序列相似性为32.20%~33.52%,且在进化树上聚为一类,推测其可能与抗霜霉病相关。同源进化分析结果表明,除SP7外,其余序列均为non-TIR-NBS-LRR类抗病基因,并与推导的氨基酸序列多重比较结果一致。     

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.     

Detection of bcl-2 methylation and the relationship between bcl-2 methylation and expression,prognostic factors in breast cancer

AIM: To establish methylation-specific PCR (MSP) method for detecting bcl-2 gene, and to study the relationship between bcl-2 methylation and expression, prognostic factors in breast cancer. METHODS: The primer of bcl-2 gene for MSP was designed. The methylations in CpG island of bcl-2 gene in 54 cases of breast cancer were detected by using MSP. The expressions of bcl-2, PCNA, ER and PR in 54 cases of breast cancer were detected by using SP immunohistochemical technique. RESULTS: The overall positive rate of bcl-2 methylation was 29.6% in breast cancer. There was a significant negative correlation between the methylation of bcl-2 and the expression of bcl-2 (P＜0.01). The methylation of bcl-2 coincided with those bad prognostic factors such as high PCNA label index (LI), ER-and PR-(P＜0.01). CONCLUSIONS: This study established the MSP method for detecting bcl-2 gene. The results of MSP and sequence analysis testified that the design of the MSP primer of bcl-2 gene in this study was successful. The methylation of bcl-2 would become the marker indicating bad prognosis of breast cancer.     

Breeding of APPSWE transgenic mice and gene identification of filial generation

AIM: To explore the ideal breeding way of APPSWE transgenic mouse (Tg2576) and identify filial generation mice with APPSWE gene for laying a foundation of AD research. METHODS: (1) Three different copulation ways were adopted to observe the survival rate and positive rate with APPSWE gene of filial generation mice. (2) The genome DNA was extracted from the tails of filial generation mice and PCR method was employed to amplify the APPSWE gene fragment. The gene type was observed by electrophoresis.(3) PCR product was inserted in pGEM-T vector to detect its gene sequence. RESULTS: The male Tg2576 mice mated with female Tg2576, and four litters were reproduced, all of them died during two days. The male Tg2576 mice mated with female C57BL, and the survival rate of their filial generation was 81% and positive rate with APPSWE gene was 43.3%. The male C57BL mice mated with the female Tg2576,and the survival rate and positive rate with APPSWE gene of filial generation mice were 82.4% and 21.9%, respectively. By Wilcoxon's Rank Sum Test, there were no significant different between the survival rates of filial generation mice by two breeding way (P＞0.05), but there were significant different between the positive rates with APPSWE gene (P＜0.05). Electrophoresis result showed the molecular weight of PCR product was 428 bp and was in accordance with that of APPSWE gene fragment. By gene sequencing, gene sequence of PCR product was verified as same as APPSWE gene double mutant. CONCLUSION: It is ideal way of breeding filial generation mice with APPSWE gene that male Tg2576 mouse mate with female C57BL. PCR technique can identify the filial generation with APPSWE gene precisely, and offer an ideal animal model for further research on AD.     

不同性别黄瓜EIN3基因片段克隆及序列分析

根据GenBank植物EIN3基因家族的保守序列设计了1对引物,以纯雌性系、强雌性系、雌雄同株系、两性花株系的不同性别黄瓜总DNA为模板,经PCR扩增得到6个725 bp左右的基因片段并进行序列比较分析。结果表明,不同性型黄瓜EIN3基因编码区有14个SNPs,平均51 bp发现1个SNP,检出率为1.96 %;其中有3个酶切位点突变,且发现编码区的SNPs有8个突变导致了氨基酸改变;初步建立了1个RFLP-BfmⅠ的酶切体系,发现在两性花株WI1983H中出现特异的酶切条带。     

牡丹ACC氧化酶基因的克隆与反义载体的构建

根据报道的牡丹ACC氧化酶基因(DQ337251)cDNA序列,设计一对特异引物,以牡丹品种"洛阳红"基因组DNA为模板,用PCR扩增方法克隆出牡丹ACC氧化酶基因的部分片段,并将其连接到pMD18-T载体上进行测序.结果表明,克隆的序列全长为467 bp,其中包括一个长度为157 bp的序列,推测它可能是一个内含子,其它序列与已报道序列同源性为98.2%;用SacⅠ和XbaⅠ对重组质粒和载体pBI 121酶切、连接,构建牡丹ACC氧化酶基因的反义表达载体.     

苹果柱型基因Co的一个AFLP 标记的SCAR转换

 将苹果柱型基因的一个AFLP 标记成功地转换成了简单实用的SCAR 标记。首先对AFLP 标记片段进行序列测定, 然后根据序列特点设计了两对特异引物CoA1/ CoA2 和CoA1/ CoA3 , 每条引物长20 bp。PCR 结果表明CoA1/ CoA2 可以扩增出216 bp 和148 bp 两条带, 其中216 bp 的为柱型性状的特征带; CoA1/CoA3 可以扩增出273 bp 和205 bp 的两条带, 其中273 bp 的为柱型性状的特征带。两对引物在杂交后代中扩增出的特征带与柱型性状的分离重组率都很低(CoA1/ CoA2 为6. 3 % ±2. 5 %; CoA1/ CoA3 为7. 3 % ±2. 6 %) , 所以它们都可以作为该SCAR 标记的特异引物所用。     

利用nrDNAITS探讨雄性不育“YX-1”与宁夏枸杞的亲缘关系

采用改进CTAB法提取枸杞叶片DNA,利用合成的特异引物对其DNA中nrDNA ITS区进行扩增、克隆,对目的片段测序分析.利用nrDNA ITS(核核糖体DNA基因内转录间隔区)序列,探讨枸杞雄性不育材料"YX-1"与其它7份宁夏枸杞材料的亲缘关系.结果表明:首次测序得到了枸杞雄性不育材料和其它7份枸杞种质的nrDNA ITS区碱基序列,整个ITS序列长度变异范围为559～633 bp,平均为612 bp,初步从基于ITS序列得出的NJ聚类图可以判断枸杞雄性不育"YX-1"在DNA水平与其他7个枸杞品种存在差异,其与四倍体88024亲缘关系较近.基于nrDNA ITS区序列分析可作为探讨枸杞雄性不育材料"YX-1"亲缘关系的一种新方法.     

粗柄鸡枞菌总DNA提取及其ITS区克隆测序研究

利用2种DNA提取方法获得了粗柄鸡枞菌总DNA,并比较了2种方法之间的提取效果,利用分子生物学方法扩增并克隆出粗柄鸡枞菌长632 bp的ITS区序列,为以后的鸡枞菌培养及鉴定奠定了一定的基础。