Effects of inhibition of ubiquitin-proteasome pathway on human primary leukemic cells

Though there were a lot of reports about the totally different responses to the inhibition of ubiquitin-proteasome pathway in different kinds of cell lines, much less has been known about the responses in primary human leukemic cells. In this study, the effects of inhibition of ubiq-uitin-proteasome pathway on human bone marrow (BM) mononuclear cells (MNCs) obtained from 10 normal persons and 8 leukemia patients were examined. The results showed that the responses obviously varied individually. Among them, BM MNCs in 3 cases of leukemic patients were extremely sensitive, demonstrated by that > 90% cells were induced to undergo apoptosis within 24 h, but MNCs in 10 cases of normal persons showed resistance to the inhibition and no apoptosis was observed. Furthermore, Western blots revealed that the Bcl-2 expression was relatively high in the sensitive primary leukemia cells, and especially the cleavage of 26 ku Bcl-2 into a 22 ku fragment occurred during the induction of apoptosis. In contrast, the Bcl-2 expression was either undetectable or detectable but no cleavage of that above was observed in the cells insensitive to the inhibition of the pathway (including BM MNCs in normal persons). Together with the observations on the leukemic cell lines, these findings suggested the correlation of the specific cleavage of Bcl-2 into a shortened fragment with the sensitivity of cells to the inhibition of ubiquitin-proteasome pathway, which provides clues to the further understanding of the mechanisms of that dramatically different responses existing in different kinds of cells to the inhibition of ubiq-uitin-proteasome pathway.     

PKC对人mdr1基因转录调控的研究

研究了ＰＫＣα、β１和β２亚型对多药耐药基因ｍｄｒ１转录的调控作用．以ｍｄｒ１基因上游调控序列驱动的虫荧光素酶报告基因表达载体和ＰＫＣ基因表达载体共同转染ＣＯＳ７细胞后,测定虫荧光素酶报告基因表达水平．实验结果表明,ＰＫＣα、β１及β２对ｍｄｒ１基因的转录有下调作用,ＰＭＡ可进一步加强这一作用;在此转染体系中,ＰＫＣ抑制剂ｓｔａｕｒｏｓｐｏｒｉｎｅ也可抑制ｍｄｒ１基因的转录,但在只转染ｍｄｒｌｕｃ的细胞中,ｓｔａｕｒｏｓｐｏｒｉｎｅ对ｍｄｒ１的转录则没有影响,提示ｓｔａｕｒｏｓｐｏｒｉｎｅ仅在ＰＫＣ过量表达的细胞中抑制ｍｄｒ１基因的转录．     

陕西蜻蜒一新种及一新亚种记述（蜻蜒目：大蜒科、丽偬科）

陕西蜻蜒一新种及一新亚种记述（蜻蜒目：大蜒科、丽偬科）杨祖德,李树森（汉中师范学院生物系。陕西７２３００１）角臀蜒属ＮｅａｌｌｏｇａｓｔｅｒＣｏｗｌｅｙ,１９３４是一个小属,其种类大都分布于喜马拉雅地区。它与大蜒属Ｃｏｒｄｕｌｅｇａｓｔｅｒ亲缘关系极...     

我国结膜吸吮线虫在是间宿主—变色纵眼果蝇体内发育过程的研究

以结膜吸吮线虫产在家兔眼分泌物仙的初产蚴和解剖雌虫子宫内的幼虫,喂饲实验室繁殖的变色纵眼果蝇进行感染,证明了变色纵眼果蝇可作为我国结膜吸吮线虫的是间宿主。经终宿主眼分泌物中的初产蚴喂饲果蝇,结果在感染后第１６天,于存活的１１只果蝇中,在２只雄蝇的口器和头部检出感染期幼虫９条。用取自雌虫体内的幼虫,平均每蝇５条幼虫的比例喂饲感染６０８只果蝇,结果检出阳性蝇１０６只,其感染率为１７．４％。并发现幼虫在     

化学合成的人免疫干扰素基因在E.coli中表达

山人的免疫干扰素(hIFN—r)基因,启始和终止信号加上适当的限制酶位点组成的一个454bp的双链DNA片段被总地合成了。该合成包括用快速的固相法制备的62个寡脱氧核苷酸,以及用酶连接这些寡核苷酸。这个合成的基因在lacuv5启动子控制之下,在E.coli中表达。表达产物具有抗病毒活性,该活性系对酸不稳定并完全地被抗hIFN—r抗血清中和,但不能被抗hIFN—α或者hIFN—β抗血清中和。用凝胶过泸法和SDT—聚丙烯酰胺凝胶电泳分别地测出E.coli产生的hIFN—γ的分子量约为32,000和17,000。     

生长素对离体黄瓜子叶生根的促进作用

植物茎或叶所发生的根,称不定根。不定根有扩大植物吸收面积和增强固着或支持植物的功能。生产上利用植物茎、叶能产生不定根的特性进行扦插、压条等营养繁殖,所以不定根发生在农业、林业和园艺上具有非常重要的意义。不定根的发生是由一些相关因素所控制的,其中包括物...     

转基因鱼

引言 利用显微注射技术已经在一定范围内产生了一些转基因动物种,而这项技术在鱼类上的应用也正在取得某种程度的成功。研究用于鱼类的最佳显微注射技术及探讨一种用于大批量培养的改良方法终将导致在商业生产规模上出现转基因鱼品种,这种鱼能将所需要的特性如快速生长,疾病抗性等转递给后代。