P_(77)PMC癫痫大鼠胆囊收缩素基因剂量的研究

胆囊收缩素(CCK)是一种脑肠肽,它在哺乳动物中枢神经系统的含量比任何一种已知的其它调节性激素的含量都高。我们曾发现P_(77)PMC癫痫大鼠脑中CCK含量比正常大鼠低。CCK的降低可能是由于该基因缺失或重排等异常改变造成的;也可能是该基因表达调控失常造成的。为此,我们利用从国外引进的,克隆有CCK cDNA的质粒pCCK作探针,应用Sou-     

聚合酶链反应及其在临床和基础研究中的应用

聚合酶链反应(PCR)又称体外基因扩增。自1985年Saiki等人首次报道PCR技术以来,在几年时间内,PCR已广泛地应用于临床医学、遗传学和分子生物学的许多研究之中。PCR可以看作是一种无细胞的分子克隆技术,它的一个重要特点是其极高的灵敏度。一些手术标本,活检组织,脱落的头发根细胞,多年的石腊切片,甚至单个细胞的DNA或RNA都能经PCR扩增     

老年性痴呆相关的β-淀粉样蛋白基因的剂量研究

用编码老年性痴呆脑中老年斑核仁成分β-淀粉样蛋白(β-Amyloiol Protein,β-AP)的cDNA探针测定老年性痴呆及正常老人的该基因剂量,结果显示老年性痴呆患者的β-AP基因剂量较正常人高。     

DETERMINATION OF THE EFFECT OF THE MUTATION IN TS20, A DNA MUTANT OF BALB/3T3 CELLS ON DNA TOPOISOMERASE Ⅱ

A temperature-sensitive mutant of Balb/3T3 cells, ts20, is defective in an early step of DNA chain elongation. Previous work has shown an association of the defect with the activity of DNA topoisomerase Ⅰ. In the studies presented herein we looked for evidence implicating the activity of DNA topoisomerase Ⅱ. Mutant, revertant and wild-type cells were equally sensitive to killing by novobiocin, a drug that inhibits the activity of DNA topoisomerase Ⅱ. The degree of inhibition of cell DNA synthesis in vivo and in vitro in mutant cells at restrictive temperature was also unaltered by the presence of the drug. The mutation had no effect on cell chromatin conformation or on supercoiling of mature polyomavirus DNA molecules. Our results provide evidence that DNA topoisomerase Ⅱ is not affected by the mutation in ts20.     

基因工程与生育调节研究

大多数激素属于两人类有机化合物:多肽和类固醇。参与生育调节的多肽激素有促性腺激素释放激素(GnRH),绒毛膜促性腺激素(CG),黄体生成素(LH),促卵泡激素(FSH),催产素(OT),催乳素(PR)等等。这些多肽激素是基因的直接产物,基因工程技术主要用于这类激素的研究。另外一些与生殖有关的激素是类固醉类,如睾丸酮     

测定Balb/3T3温度敏感变种细胞(ts 20)的变异对DNA拓扑异构酶Ⅱ的影响

ts20是从Balb/3T3鼠细胞中分离的一种温度敏感变种。在允许温度33℃时,变种细胞具有与野生型3T3细胞相同的生长特性,但在限制温度39℃时,变种细胞的DNA复制功能受到变异蛋白的影响而不能进行,从而其生长被抑制并在24小时内死亡。我们的研究证明ts20细胞的缺失蛋白是DNA复制过程中延伸早期所必需的,而且,这种蛋白与DNA拓扑     

利什曼原虫动基体DNA的提取和鉴定

动基体DNA(kDNA)是存在于一类原虫核外动基体内的网状DNA,是由许多小环彼此环连所结成的巨大的DNA分子。kDNA网状结构的生物学功能还不清楚。它的一个重要用途是作为Ⅱ型DNA柘扑异构酶解环连反应的特异性底物。此外,还可用做分类和检测利什曼原虫以及诊断某些内脏性黑热病的特异性探针。本文报告了一种简便易行的提取和鉴定kDNA的方法。     

视网膜母细胞瘤的基因分析

视网膜母细胞瘤是一种遗传性恶性肿瘤,应用 Rb 易感基因的 cDNA片段进行产前诊断是防止该病发生的有效途径。本文应用分子杂交技术,以两个克隆的 Rb cDNA 为探针,检测了两个 Rb 病人及其父母的 DNA,发现其中一个病人的 Rb 基因含有1kb 的缺失,为进一步开展 Rb 的产前诊断打下基础。     

EFFECT OF ANTITUMOR DRUGS ON THE ACTIVITY OF DNA TOPOISOMERASE I

The activity of DNA topoisomerase Ⅱ prepared from either normal or tumor tissues were compared. It was found that the unknotting activity of the enzyme in malignant tumor cells was higher than that in normal cells. We selected some antitumor drugs including Chinese traditional medicine, and observed their effects on the unknotting activity of topoisomerase Ⅱ. The results showed that inhibition of the unknotting activity of the enzyme required very low concentrations of drugs, but much higher concentrations were required for other tested. Some antitumor drugs had no effect on the enzyme were also proved. It is interesting that carrageenan, an antiviral drug, strongly blocked the unknotting activity although its antitumor activity has not been reported.