Construction and packaging of pseudotype retrovirus containing human N—ras cDNA antisense sequence and its biological effects on human hepatoma cells

N-ras is one of the transforming genes in human hepatic cancer cells.It has been found that N-ras was overexpressed at the mRNA and protein level in hepatoma cells.In order to explore the biological roles of N-ras in human hepatic carcinogenesis and the potential application in control of cancer cell growth,a preudotype retrovirus containing antisense sequence of human N-ras was constructed and packaged.A recombinant retrovirus vector containing antisense or sense sequences of N-ras cDNA was constructed by pZIP-NeoSV(X)1.The pseudotype virus was packaged ang rescued by transfection and infection in PA317 and ψ 2 helper cells.It has been demonstrated that the pseudotype retrovirus containing antisense N-ras sequence did inhibit the growth of human PLC/PRF/5 hepatoma cells accompanied with inhibition of p21 expression,while the retrovirus containing sense sequence had none.The pseudotype virus had no effect on human diploid fibroblasts.     

萝卜离体子叶衰老与膜脂过氧化的关系

萝卜离体子叶在光下或暗中衰老及激素调节衰老过程中,作为叶片衰老指标的叶绿素和蛋白质含量的降低,发生在MDA含量增高之前,更早于SOD活性的下降。表明由SOD活性降低所导致的膜脂过氧化的增强,并非衰老的原初反应,而是叶片衰老到一定程度的生理变化。因此,至少在萝卜离体子叶上,不能将其衰老的启动归因于受SOD控制的膜脂过氧化作用导致的膜累积性质变。     

紫云英根瘤菌109菌株吸氢的诱导表达——核苷、核苷酸与烟酸的促进效应

核苷酸和烟酸的添加,使紫云英根瘤菌109氢酶吸氢活性表达增加。cAMP(1 mmol/L),烟酸(70 mmol/L)的存在,缓解了葡萄糖酸钠或果糖引起的吸氢活性阻遏,cAMP的解阻遏效应在年轻的菌体(48 h)表现较为明显。但以MB为受体的破碎细胞吸氢活性则未见增加,烟酸的促进效应受到氯霉素(40μg/ml)的抑制。其他核苷或核苷酸,如腺嘌呤,尿嘧啶,ATP,ADP,AMP,UMP,UTP都能促进吸氢活性的表达。诱导氢酶前,细胞ATP库已处于低水平,并保持稳定,添加琥珀酸盐后,ATP库水平提高,吸氢活性表达受抑。     

人体基因组随机单拷贝顺序的分离及其在染色体上的定位

本文从构建杂种细胞14-7-1的基因组文库出发,用种特异的探针分离出含有人体基因组顺序的重组子,并进一步分析了其中13个克隆,得到8个单拷贝顺序。通过与已建立的杂种细胞克隆分布板杂交以及染色体的原位杂交方法,将1个单拷贝顺序FD11-1定位在11p11-q11上。由于已经报道在11号染色体上具有3个连锁群,它们分别位于11p15、11p13和11q13上,因此,FD11-1有可能为11号染色体连锁基因图的建立提供1个有意义的座位。     

热暴露大鼠心肌细胞钙稳态及其调节机制的研究

本文观察了离体成年大鼠心室肌肌质网、线粒体Ｃａ＾２＋－ＡＴＰ酶活性和总钙含是到及原代培养乳腺心肌细胞＾４６Ｃａ摄取、活性钙调素相对含量、胞浆内游离钙浓度在不同温度热暴露４０ｍｉｎ后的变化。结果表明：热暴露后,心肌奖浆、肌质网及线粒体中的Ｃａ＾２＋－ＡＴＰ酶活发表 所下降,心肌肌质网及线粒体中的总钙含量亦有降低趋势,心肌细胞活性钙调素相对含量显著下降,＾４６Ｃａ摄取量及胞浆内游离浓度显著升高。提示,     

肾素－血管紧张素系统──应激激素反应系统

各种急性与慢性应激时,循环血中及脑、心血管、肾腺等组织中血管紧张素Ⅱ（ＡⅡ）显著增多;人剧烈运动后血浆ＡⅡ与皮质醇一样均剧烈增加,在慢性应激性高血压动物循环及组织中,ＡⅡ含量持续地增高。还发现高浓度ＡⅡ对肾上腺糖皮质激素的分泌有直接的刺激作用,而组织ＡⅡ增多又受肾上腺素能β受体的激发。根据近年来的系列工作,并结合文献,我们认为ＡⅡ是一种重要的应激激素;肾素－血管紧张素系统是一个应激激素反应系统;它与经典的应激激素反应系统,下丘脑－垂体－肾上腺皮质系统及交感－肾上腺髓质系统也存在着密切的关系。     

从玉米胚中大量制备植物钙调素

从每公斤萌发２４ｈ的玉米胚丙酮粉中可提纯得６３ｍｇ的钙调素（ＣａＭ）,这是目前从每公斤植物材料中所提纯得ＣａＭ的最高记录。对其理化性质的研究表明,玉米胚ＣａＭ 有较高的生物学活性,能较好地激活磷酸二酯酶,其紫色吸收光谱,ＳＤＳ－ＰＡＧＥ电泳行为及氨基酸组成与其它的植物ＣａＭ相似。上述结果表明玉米胚是１个提取植物ＣａＭ相似。上述结果表明玉米胚是１个提取植物ＣａＭ的适宜材料。     

华东植物区系成分与日本植物间的联系

华东和日本两地为东亚地区重组成部分,同属于中国－日本森林植物亚区。两地植区物系成具有较高的相似性。两地共有连香树科（Ｃｒｃｉｄｉｐｈｙｌｌａｃｅａｅ）、三尖杉科（Ｃｅｐｈａｌｏｔａｃｅａｅ）、领春木科（Ｅｕｐｔｅｌｅａｃｅａｅ）、旌节花科ǎ樱簦幔悖瑁酰颍幔悖澹幔澹┑榷翘赜锌啤;腿毡玖降毓灿惺粼迹叮福岸嗍簟Ｈ缌迹ǎ茫颍穑簦铮恚澹颍椋幔⑺荆ǎ模椋螅幔睿簦瑁酰螅⑿」炊ǎ拢澹颍悖瑁     

Molecular cloning of a metallothionein-like gene from Nicotiana glutinosa L. and its induction by wounding and tobacco mosaic virus infection.

The cloning and characterization of genes expressed in plant disease resistance could be an initial step toward understanding the molecular mechanisms of disease resistance. A metallothionein-like gene that is inducible by tobacco mosaic virus and by wounding was cloned in the process of subtractive cloning of disease resistance-response genes in Nicotiana glutinosa. One 530-bp cDNA clone (KC9-10) containing an open reading frame of 81 amino acids was characterized. Genomic Southern blot hybridization with the cDNA probe revealed that tobacco metallothionein-like genes are present in few or in one copy per diploid genome. Northern blot hybridization detected strong induction of a 0.5-kb mRNA by wounding and tobacco mosaic virus infection, but only mild induction was detected when copper was tested as an inducer. Methyl jasmonate, salicylic acid, and ethylene were also tested as possible inducers of this gene, but they had no effect on its expression. The possible role of this gene in wounded and pathogen-stressed plants is discussed.     

过氧化心肌线粒体产生的脂类自由基及（－）－EGCG的抑制作用

本文利用ＥＳＲ技术研究了心肌线粒体酶修饰下的脂质过氧化和脂类自由基,以及（－）－ＥＧＣＧ的抑制作用。结果表明：４－ＰＯＢＮ能捕集ｌｉｐｏｘｙｇｅｎｇｓｅ诱发心肌线粒体产生的自由基,得到６条线谱的脂类自由基和４条线谱捕集物,（－）－ＥＧＣＧ对该体系中使用的１ｉｐｏｘｙｅｎａｓｅ活性无影响,对所产生的自由基有明显的清除作用,并呈量效关系。对脂质过氧化的抑制作用,在本试验浓度范围内随浓度增加变化不大,最大抑制率约２０％。