卵巢癌相关基因的克隆

目的：筛选和克隆卵巢上皮癌相关基因。方法：用3种锚定引种和8种随机引物,共24种组合进行PCR扩增,通过DD－RTPCR分析正常卵巢上皮和卵巢上皮癌mRNA的基因表达差异,将差异片段分离出来,并回收,克隆和进行斑点杂交鉴定、DNA序列测定,并通过国际互联网张检索GenBank进行同源性分析。结果：获得30个差异表达的片段,经斑点杂交初步筛选,克隆11个差显示的阳性片段。选取其中的5个进行序列分析。结论计算机同源性分析表明,5个均为新基因片段,已收录GenBank。     

胃癌高表达cDNA片段W41的克隆及组织表达谱分析

目的：从人胃癌组织中克隆新的相关易感基因。方法：利用cDNA末端快速扩增PCR技术得到了扩增片段，将其克隆、核苷酸序列分析，并将序列在GenBank进行同源性比较。利用Northern杂交、多组织Northern及基因表达系列分析了所得基因片段的组织表达谱。结果：获得1条533bp带有poly(A)尾的cDNA片段，可见加尾信号AATAAA，与GenBank基因数据库同源比较，该序列未见与任何已知基因同源，登录GenBank(登录号为AF325202）。该序列在胃癌组织的表达强度高于对应正常组织，多组织Northern及基因表达系列分析表明该序列在多种肿瘤组织中高表达，在正常组织中表达减弱。结论：得到了1条与胃癌可能相关的新的cDNA序列。     

小鼠PGRP-L编码区基因的克隆及序列分析

目的：获得小鼠长型肽聚糖识别蛋白（mPGRP—L）全长编码区基因。方法：采用RT—PCR技术，从BALB／c鼠肝组织总RNA中扩增PGRP-L编码区基因片段，将其插入pUCm-T载体，以PCR和测序进行鉴定。结果：从BALB／c小鼠肝脏cDNA中，分别以Primer—F和Primer—R1、Primer—F1和Primer—R为引物对进行PCR，扩增得到约1050bp的上游基因片段和约540bp的下游基因片段。以纯化的上、下游片段为模板，Primer—F和Primer—R为引物进行PCR，扩增获得约16aHDbp的DNA片段，并将其克隆至pMD18-T载体获得重组质粒pMD18-mPGRP-L。鉴定结果表明，mPGRP—L编码区基因全长1593bp，与GenBank中mPGRP—LcDNA比较仅2个位置的核苷酸不同，两者的同源性为99．87％。结论：成功地克隆了mPGRP—L的cDNA，为mPGRP—L分子的研究奠定了一定基础。     

Dystrophin基因常见易缺失外显子片段的克隆

目的对Dystrophin基因18个常见易缺失外显子片段进行克隆、鉴定,以克隆产物作为核苷酸探针为研制Dystrophin基因缺失检测微阵列作准备。方法以人类基因组DNA为模板,应用18对引物,对Dystrophin基因常见易缺失外显子片段进行PCR扩增。将扩增产物与pGEM-T Easy载体连接,转化E．coli JM109感受态细胞。通过平板培养,挑选阳性克隆。提取重组质粒,Not I酶切,获得完整的探针片段,并作测序鉴定。通过核酸序列数据库相似性检索工具验证序列的来源及其与GeneBank收录序列的相似性。结果PCR扩增出18个片段,与Dystrophin基因预期扩增片段大小相一致。重组克隆的酶切产物与PCR产物大小相近,与预期相一致。经测序获得18个克隆片段全序列,其核苷酸数量与预期基本一致,序列相似性检索分析证实了这些克隆片段与GeneBank收录的Dystrophin基因片段具有极高的同源性。结论克隆产物确为Dystrophin基因常见易缺失外显子片段。     

阿尔茨海默病患者血液细胞线粒体内细胞色素C氧化酶亚基Ⅱ基因存在缺失

目的 调查25例老年痴呆患者血细胞线粒体中细胞色素C氧化酶亚基Ⅱ基因的突变情况,探讨线粒体DNA突变与阿尔茨海默病(AD)性老年痴呆发生发展的关系。方法 采用微量法提取血细胞总DNA直接作为PCR模板,进行巢式PCR扩增,最后采用DNA序列分析鉴定突变。结果在正常老人组,只扩增了280bp的线粒体细胞色素C氧化酶亚基Ⅱ基因(COX2)扩增片段,而在老年痴呆患者中出现了464bp和280bp的多态性扩增片段,并且发现了1个320bp的新的线粒体DNA缺失片段,1位AD患者的COX2基因存在一种新的缺失后重组现象,COX2基因的1条单链在np7503处断裂,另1条单链在np7785处断裂,这两个断裂的游离片段通过插入1个额外的胞嘧啶核苷酸重新连接起来。结论 老年痴呆患者中的COX2基因存在片段扩增多态性。     

MPTP损伤侧猴中脑黑质组织的基因表达

目的：采用mRNA差异显示技术（mRNA differential display,mRNA DD)寻找MPTP诱导和未诱导的猴中脑黑质组织差异表达的cDNA。方法：对诱导侧及未诱导侧的黑质mRNA用3′端3个锚定引物分别与5′端30种随机引物进行逆转录－聚合酶链反应（RT－PCR）扩增产物经聚丙烯酰胺凝胶电泳及硝酸银染色显示目的的条带。结果：获得一批表达差异的cDNA片段，对其克隆后作DNA序列测定，同源性比较分析发现，其中2个克隆为未知序列，已被GenBank接收，接收号为AF159161、AF159162。结论：MPTP诱导后黑质可能有效新基因的表达。     

dystrophin基因常见易缺失外显子片段的克隆和鉴定(英文)

背景:dystrophin基因是人类常见的X染色体连锁隐性遗传的神经-肌肉系统疾病,dystrophin基因缺失集中在两个热点区域即外显子2～20和44～53,其主要缺失可以通过对一系列外显子的检测来发现。然而对dystrophin基因缺失的18个常见易缺失外显子片段的系统检测却鲜有报道。目的:拟对dystrophin基因18个常见易缺失外显子片段进行克隆、鉴定。方法:以人类基因组DNA为模板,应用18对引物对dystrophin基因常见易缺失外显子片段进行PCR扩增。将扩增产物与pGEM-TEasy载体连接,转化E.coliJM109感受态细胞。通过平板培养,挑选阳性克隆。提取重组质粒,NotI酶切,获得完整的探针片段,并作测序鉴定。通过核酸序列数据库相似性检索工具验证序列的来源及其与GeneBank收录序列的相似性。结果与结论:PCR扩增出18个片段,与dystrophin基因预期扩增片段大小相一致。重组克隆质粒的酶切产物与PCR产物大小相近,与预期相一致。经测序获得18个克隆片段全序列,其核苷酸数量与预期基本一致,序列相似性检索分析证实了这些克隆片段与GeneBank收录的dystrophin基因片段具有极高的同源性。克隆产物确为dystrophin基因常见易缺失外显子片段。     

致倦库蚊溴氰菊酯抗性株细胞色素P450基因的克隆,鉴定及同 …

根据果蝇的ＣＹＰ４Ｄ１保守区氨基酸序列，设计了１对简并引物，从致倦库蚊溴氰菊酯抗性株的基因组ＤＮＡ中，扩增出１条特异性ＤＮＡ片段，其大小与设计的细胞色素Ｐ４５０基因片段相符。将这个片段与ｐＵＣ１９质粒重组，并克隆到ＤＨ５α大肠杆菌中，经筛选后测序，得到１条长４５６的核酸序列。将推导的氨基酸序列进行同源性分析，表明该序列与ＣＹＰ４家族成员同源性较高，提示该序列属于ＣＹＰ４家族；该序列与ＣＹＰ４Ｊ亚家     

人肝癌细胞系中肿瘤相关基因MAGE的克隆

目的 克隆人肝癌细胞系HHCC中的肿瘤相关基因MAGE－1的全长cDNA。方法 根据GenBank中MAGE－1基因编码区，设计PCR引物，用RT-PCR手稿,人人肝癌细胞系HHCC中获得MAGE－1全长cDNA，双酶切后连接入质粒pUC19中，转化入大肠杆菌DH5α。挑选阳性克隆提取质粒，进行DNA序列分析，并将测得的核苷酸序列与GenBank中的DNA序列进行BLAST同源性分析。结果 获得MAGE－1全长cDNA,MAGE-6基因463bp片段，以及1个与MAGE－6基因编码区有93％同源性的片段，可能为MAGE家族中的新成员。结论 人肝癌细胞系HHCC可表达多种MAGE基因，可能有效的MAGE基因出现，为研究MAGE基因在HCC中的表达模式及其在HCC免疫治疗中的靶点提供了新的资料。     

利用套式PCR技术鉴别屋尘螨和粉尘螨主要变应原基因及其在尘螨疫苗研制中的应用

通过提取屋尘螨和粉尘螨疫苗研制用的原始种子和生产种子基因组DNA作模板,分别设计Der p1和Der f1各2套内外扩增引物并进行一步法套式PCR,根据扩增出目的片段来检测尘螨变应原Der p1和Der f1基因片段,并以培养基提取物为阴性对照和已通过形态学鉴别为纯屋尘螨、纯粉尘螨的基因组DNA为阳性对照。PCR产物经电泳后切胶回收并克隆到T载体上,进行DNA序列分析并在GenBank中进行同源性比较。结果显示,从屋尘螨和粉尘螨疫苗研制用的原始种子和生产种子分别扩增出含有屋尘螨和粉尘螨主要变应原Der p1和Der f1基因片段,扩增部分的序列与GenBank数据库里相应序列同源性为100%。从阴性对照提取物中未扩增得到目的基因片段,从阳性对照DNA提取物中能扩增得到目的变应原Der p1和Der f1基因片段。本研究首次应用套式PCR技术鉴别了屋尘螨和粉尘螨原始种子和生产种子,为尘螨疫苗研制以及工业化生产提供了一种有效的质量控制手段。     

Molecular characterization of invasive and noninvasive Campylobacter jejuni and Campylobacter coli isolates

Campylobacter jejuni is one of the most common causes of bacterial diarrhea worldwide and is the primary bacterial cause of food-borne illness. Adherence to and invasion of epithelial cells are the most important pathogenic mechanisms of Campylobacter diarrhea. Molecular characterization of invasive and noninvasive Campylobacter isolates from children with diarrhea and symptom-free children was performed by random amplified polymorphic DNA techniques (RAPD). A distinct RAPD profile with a DNA band of 1.6 kb was observed significantly more frequently among invasive (63%) than among noninvasive (16%) Campylobacter isolates (P = 0.000005). The 1.6-kb band was named the invasion-associated marker (IAM). Using specifically designed primers, a fragment of 518 bp of the iam locus was amplified in 85% of invasive and 20% of noninvasive strains (P = 0.0000000). Molecular typing with a PCR-restriction fragment length polymorphism assay which amplified the entire iam locus showed a HindIII restriction fragment polymorphism pattern associated mainly with invasive strains. Although cluster analysis of the RAPD fingerprinting showed genetic diversity among strains, two main clusters were identified. Cluster I comprised significantly more pathogenic and invasive isolates, while cluster II grouped the majority of nonpathogenic, noninvasive isolates. These data indicate that most of the invasive Campylobacter strains could be differentiated from noninvasive isolates by RAPD analysis and PCR using specific primers that amplify a fragment of the iam locus.     

Toxoplasma gondii virulence markers identified by random amplified polymorphic DNA polymerase chain reaction

Genomic DNAs from 35 Toxoplasma gondii strains were amplified by random amplified polymorphic DNA (RAPD) polymerase chain reaction (PCR) using 18 arbitrary 10-mer primers. At least four primers were found to generate DNA fragments that discriminate the 35 T. gondii strains into a genotype of virulent strains and a genotype of avirulent strains. Primer B12 was found to generate a virulence-specific fragment and primers B5, C8, and C20 were found to generate avirulence-specific fragments, which in all cases clearly identified either the virulence phenotype or the avirulence phenotype, respectively. In addition, the DNA polymorphic bands detected were analyzed by parsimony and distance analysis. A similar genetic relationship among the T. gondii strains was determined by the two phylogenetic methods, which use completely different assumptions. Consistent with the division of the 35 strains into a genotype of virulent strains and a genotype of avirulent strains, both analyses revealed 2 clonal lineages directly correlated with murine virulence. These results strongly support the hypothesis that the genus Toxoplasma may actually contain two clonal lineages correlated with virulence, which have evolved independently following their initial separation. Received: 1 October 1996 / Accepted: 15 October 1996     

Strain differentiation in Bacteroides fragilis by RAPD and Dendron computer-assisted gel analysis

Batteroides fragilis is the anaerobe most frequently isolated from human infections. Strains of this species are not easily distinguished by phenotypic tests. It is important to make this distinction because virulence may vary between strains and because B. fragilis seems to be a heterogeneous species. The aim of this study was to assess the utility of randomly amplified polymorphic DNA (RAPD) analysis for differentiation of 46 strains of B. fragilis. Twenty-seven of the strains belonged to Johnson's DNA homology group I and 8 to group II, while 11 strains had not been assigned to any of these groups (NI group). The primers OPA16 and 18 were chosen among 30 primers tested for optimal RAPD analysis. OPA18 gave best discrimination, revealing a total of 15 genotypes while OPA16 gave 13. The gels obtained after RAPD analysis were evaluated with the Dendron computer-assisted program. Most strains showed similarity levels (S(AB)) within 70%. Strain clusters thus established were not always in agreement with DNA homology since strains from both homology groups fell in the same cluster. Similarly, strains of the NI group fell among the group I and II homology strains. RAPD was useful for differentiation of B. fragilis strains and thus probably suitable for epidemiological studies. On the other hand, DNA-DNA homology, comparing the entire genome of strains rather than a few random priming sites, would be more reliable for taxonomy. Computer-assisted gel analysis made it possible to objectively evaluate multiple banding patterns, thereby increasing the reliability of the RAPD analysis.     

RAPD–SCAR marker and genetic relationship analysis of three Demodex species (Acari: Demodicidae)

For a long time, classification of Demodex mites has been mainly based on their hosts and phenotype characteristics. The study was the first to conduct molecular identification and genetic relationship analysis for six isolates of three Demodex species by random amplified polymorphic DNA (RAPD) and sequence-characterized amplified region (SCAR) marker. Totally, 239 DNA fragments were amplified from six Demodex isolates with 10 random primers in RAPD, of which 165 were polymorphic. Using a single primer, at least five fragments and at most 40 in the six isolates were amplified, whereas within a single isolate, a range of 35-49 fragments were amplified. DNA fingerprints of primers CZ 1-9 revealed intra- and interspecies difference in six Demodex isolates, whereas primer CZ 10 only revealed interspecies difference. The genetic distance and dendrogram showed the intraspecific genetic distances were closer than the interspecific genetic distances. The interspecific genetic distances of Demodex folliculorum and Demodex canis (0.7931-0.8140) were shorter than that of Demodex brevis and D. canis (0.8182-0.8987). The RAPD-SCAR marker displayed primer CZ 10 could be applied to identify the three Demodex species. The 479-bp fragment was specific for D. brevis, and the 261-bp fragment was specific for D. canis. The conclusion was that the RAPD-SCAR multi-marker was effective in molecular identification of three Demodex species. The genetic relationship between D. folliculorum and D. canis was nearer than that between D. folliculorum and D. brevis.     

Characterization of Streptococcus agalactiae strains by randomly amplified polymorphic DNA analysis.

A collection of 54 unrelated Streptococcus agalactiae strains isolated from cerebrospinal fluid samples from neonates and 60 unrelated strains isolated from carriers that had been previously studied by multilocus enzyme electrophoresis (R. Quentin, H. Huet, F.-S. Wang, P. Geslin, A. Goudeau, and R. K. Selander, J. Clin. Microbiol. 33:2576-2581, 1995) were characterized by randomly amplified polymorphic DNA (RAPD) assay. Four primers, 5'AGGGGGTTCC3', 5'AACGCGCAAC3', 5'GCATCAATCT3', and 5'AGTCGGGTGG3', named OPS16, AP42, A4, and OPS11, respectively, were selected from 29 primers tested. This investigation identified 71 RAPD types. The three families of strains defined by multilocus enzyme electrophoresis analysis, which contain most of the cerebrospinal fluid isolates, were also identified by clustering analysis of RAPD data. Each of these three groups exhibits specific RAPD patterns or fragments. The discriminatory power of the RAPD typing method was also evaluated. The simplest typing scheme was obtained by the combination of RAPD typing done with primers AP42 and OPS11 and serotyping (index of discrimination, 0.97).     

Molecular nature of RAPD markers from Haemophilus influenzae Rd genome

Despite the widespread application of the random amplified polymorphic DNA (RAPD) technique, there is no experimental evidence of the molecular mechanism of random amplification starting from a complex template. To investigate this mechanism, we cloned and sequenced 23 selected RAPD bands amplified from Haemophilus influenzae Rd genomic DNA using eight decamer primers different in GC content and/or nucleotide sequence. As the whole genome sequence of H. influenzae Rd has been reported, the exact nucleotide sequence of each primer-template annealing site was identified. Results showed that, on an average, a homology of eight base pairs was involved in priming events and that the number of nonhomologous base pairings declined exponentially from the 5' end of the primer to its 3' end. The interaction between the primer and the template DNA was stabilized by the formation of secondary structures, and a perfect match of the 3' terminal region of the primer was not necessary for successful amplification. The complexity of the annealing process suggested that, in the studied reaction conditions, many primer-template annealing sites were extended in the first cycles and that differences in the efficiency of priming and replication processes led to amplification of RAPD fragments. Moreover, the distribution of the amplified regions on the H. influenzae chromosome was analyzed.     

自发性高血压大鼠的基因组多态性

目的:应用随机扩增多态DNA聚合酶链反应（RAPD-PCR）技术分析自发性高血压大鼠（SHR）的基因组多态性。 方法:运用100条引物对WKY和SHR的DNA进行RAPD-PCR扩增，琼脂糖凝胶电泳观察。 结果:与WKY相比，100条引物中有13条引物出现基因组多态性，SHR扩增产物的电泳条带出现增加、丢失、移位和密度改变，其它87条引物扩增结果无明显改变。 结论:SHR存在基因组多态性，RAPD-PCR方法可用于检测SHR的基因组多态性。     

Rapid extraction of fungal DNA from clinical samples for PCR amplification.

A hexadecyltrimethylammonium bromide (CTAB) method for isolating fungal DNA from clinical samples, suitable for PCR amplification is described. Yeast and filamentous fungi DNA from clinical samples was amplified with primers complementary to the genes coding for rRNA, amplifying a 105 bp fragment and internal transcribed spacer primers amplifying fragments between 242 and 622 bp. The level of sensitivity was 10 +/- 5 yeast and 28 Aspergillus fumigatus CFU ml-1 of biological fluid.     

Evidence of two genetic entities inBothriocephalus funiculus (Cestoda) detected by arbitrary-primer polymerase chain reaction random amplified polymorphic DNA fingerprinting

The genetic diversity of two samples of Cestoda (Bothriocephalus funiculus, Renaud and Gabrion, 1984) parasitizing two sympatric teleostean species was assessed using random amplified polymorphic DNA (RAPD). A total of 72Bothriocephalus were analyzed individually, and electrophoretic analysis of the amplification products of 65 primers among the 68 tested revealed monomorphic patterns, reflecting the close genetic relatedness within and between the parasites of the two samples. However, 3 primers showed polymorphic patterns at 6 RAPD sites. Analysis of the distribution of these genomic fragments, assuming random mating, showed strong linkage disequilibria (only 8 genetic combinations were observed among the 32 expected). Two genetic entities displaying a high degree of host specificity were evidence within our two samples ofB. funiculus. This powerful molecular technique can be used as a diagnostic tool in studies concerning the biodiversity of related genetic entities and could have broad applications in parasitology.     

Detection of RAPD Markers Correlated with Chloroquine Resistance in Plasmodium falciparum

We described the use of the random amplified polymorphic DNA (RAPD) technique on Plasmodium falciparum DNA to detect genetic markers for chloroquine-resistant strains. Fourteen RAPD primers were tested, three of which generated banding patterns correlated with chloroquine resistance. To measure this correlation, the RAPD profiles were analyzed using the Nei and Li similarity coefficient. Detection of distinctive RAPD bands allowed us to synthesize specific PCR primers to be used on whole-blood samples. Two primer sets were synthesized and tested on sensitive and resistant strains for their ability to amplify the DNA fragment corresponding to the RAPD marker. These results suggest that RAPD and PCR techniques can be used as powerful tools for the detection of genetic markers associated with drug resistance.