核蛋白基本单元的合成－O－乙基－UMP－丙氨酸甲酯

在合成磷酰蛋白的模型化合物体Ｎ－（Ｏ,Ｏ－二烷基）磷酰化氨基酸（１）的基础上,首次合成了有机磷生命化学的模型化合物──核蛋白基本单元Ｎ－（Ｏ－烷基,Ｏ－核苷）磷酰化氨基酸（２）,并对上述物质进行了分离、鉴定、比较了两种模型的合成方法。这对在小分子水平上,深入研究磷酰基的参与作用和蛋白质与核酸之间的互相作用机理提供了较好的模型化合物。     

金属内肽酶底物Glutaryl－Ala－Ala－Phe－2NA的合成

文本以苯丙萘胺（Ｐｈｅ－２ＮＡ）为原料,通过Ｂｏｃ－Ｎ－羟基丁二酰亚胺活化酯法合成了金属内肽酶底物Ｇｌｕｔａｒｙｌ－Ａｌａ－Ａｌａ－Ｐｈｅ－２ＮＡ     

5－氮－2＇－脱氧胞苷（5－aza－CdR）对HL－60细胞分化和DNA甲基化酶的影响

以５－氮－２＇－脱氧胞苷（５－ａｚａ－ＣｄＲ）为诱导物,在０．５μｍｏｌ／Ｌ的最佳浓度下,可诱导ＨＬ－６０细胞分化达１５％左右。同时,用［￣３Ｈ］－ｍｅｔｈｙｌ－ｓ－ａｄｅｎｏｓｙｌｍｅｔｈｉｏｎｉｎｅ（￣３Ｈ－ＳＡＭ）为底物,通过同位素参入法,测定了不同浓度诱导物对ＨＬ－６０细胞ＤＮＡ甲基化酶活力的影响,发现在最佳诱导物浓度下,可使ＨＬ－６０细胞ＤＮＡ甲基化酶活力明显下降,此外,也比较了不同分化水平的ＨＬ－６０细胞中具有不同甲基化水平的ＤＮＡ在体外接受甲基的能力,从而证明５－ａｚａ－ＣｄＲ诱导ＨＬ－６０细胞分化与其ＤＮＡ甲基化状态密切相关。     

磷酸－Tyr－Sepharose吸附法测定HL－60细胞中磷脂酰肌醇－3－激酶

 磷酸－Ｔｙｒ－Ｓｅｐｈａｒｏｓｅ吸附法测定ＨＬ－６０细胞中磷脂酰肌醇－３－激酶黄才,梁念慈（广东医学院医用生化研究所,湛江５２４０２３）磷脂酰肌醇－３－激酶（ＰＩ－３－Ｋ）催化磷脂酰肌醇（ＰＩ）和磷脂酰肌醇－４－磷酸（ＰＩ－４－Ｐ）的磷酸化分别生成磷...     

稻－萍－蟹立体农业的效益

稻－萍－蟹立体农业的效益朱清海，李毓鹏，徐春河（辽宁省盘锦市土肥工作站，１２４０１０）魏晓敏毛艳，朱浩峥（辽宁省盐碱地利用研究所，盘锦１２４２００）（辽宁省盘锦市土肥工作站，１２４０１０）ＢｅｎｉｆｉｔｏｆＳｔｅｒｅｏｓｃｏｐｉｃＡｇｒｉｃｕｌｔｕｒ...     

重复基因的进化－－回顾与进展

基因重复是普遍存在的生物学现象, 是基因组和遗传系统多样化的重要推动力量, 在生物进化过程中发挥着极其重要的作用。基因重复有何利弊, 基因发生重复后, 2个重复子拷贝的保留在基因功能方面是否存在偏好性, 子拷贝在表达和进化速率上如何分化, 以及重复基因为什么会被保留下来一直是进化生物学领域研究的热点问题之一。该文对以上重复基因研究的热点问题进行了介绍, 并对重复基因的进化机制和理论模型及其近年来的一些主要研究进展进行了综述。     

B－E－A毒素的作用机制

Ｂ－Ｅ－Ａ毒素的作用机制毛献荣（中国科学院上海生物化学研究所,上海２０００３１）关键词Ｂ－Ｅ－Ａ毒素,酶活力许多细菌和植物都能产生对哺乳动物有很强细胞毒性的蛋白质,并且它们在结构和作用方式上都很不同。一般根据毒素的主要的破坏位点是在胞液中（通过酶活性...     

维生素c发酵中2－酮－L－古龙酸还原酶的研究

由于2－酮－L－古龙酸还原酶(简称KGR)的存在,理论上造成了Vc合成前体2－酮－L－古龙酸(简称2KLG)部分被还原成L－艾杜糖酸〔1.2〕,影响了Vc二步发酵的产率。而从L－山梨糖到2－酮－L－古龙酸的转化中,除被KGR催化的还原负反应外,均属于氧化反应。所以,从该角度出发,抑制KGR的活性,消除还原负反应,是提高2KLG产酸率,进而提高Vc二步发酵产率的关键。本研究在纯化KGR的基础上⑶,对其物质组成及性质进行了研究,并研制了几种稀土元素化合物,考察了它们对KGR纯酶及在L－山梨糖发酵中对2－KLG产酸率的影响。     

番茄果实中焦磷酸：D－果糖－6－磷酸1－磷酸转移酶的结构和动力学特性

比较了番茄绿果实和红果实中焦磷酸－Ｄ－果糖－６－磷酸１－磷酸转移酶的两种酶型（Ｑ１和Ｑ２）的结构和动力学特性。绿果实中大分子酶型Ｑ２（绿Ｑ２）在酶蛋白量和酶活力方面均占绝对优势,而在红果实中小分子酶型Ｑ１（红Ｑ１）起主导作用。ＳＤＳ－ＰＡＧＥ凝胶扫描结果显示绿Ｑ２和红Ｑ２（红果实中大分子酶型）的亚基组成不同。组成该酶的α－基（６６ｋＤ）和β－亚基（６０ｋＤ）的化学裂解肽谱表明两亚基差异很大,同时证明构成Ｑ１和Ｑ２的β亚基具有相同的肽谱。分析Ｑ１和Ｑ２的圆二色性（ＣＤ）光谱表明绿Ｑ２和红Ｑ２均主要由α－螺旋和β－折叠构成二级结构,几乎没有无规卷曲。动力学分析表明激活剂果糖－２．６－二磷酸不同程度地影响Ｑ１和Ｑ２对正反应底物的亲和力,而对逆反应活性无明显影响。绿Ｑ２的正反应和逆反应最大活力比值低于绿Ｑ１,红果实中则反之。     

丝状真菌SC－2产β－胡萝卜素的研究

利用改良的ＳＭＡ培养基富集培养从植物的落花上分离筛选出的产β─胡萝卜素的菌株ＳＣ—２。该菌株在以棉籽饼粉为主要原料的培养基上生长良好。最高生物量达５４ｍｇ干菌体／ｍｌ培养液。胡萝卜素含量１．８５ｍｇ／ｇ干菌体。ＨＰＬＣ测定β─胡萝卜素占总胡萝卜素的９０．５％。     

Genetic Transformation of Tobacco with the Trehalose Synthase Gene from Grifola frondosa Fr. Enhances the Resistance to Drought and Salt in Tobacco

Trehalose is a non-reducing disaccharide of glucose that functions as a protectant in the stabilization of biological structures and enhances the tolerance of organisms to abiotic stress. In the present study, we report on the expression of the Grifolafrondosa Fr. trehalose synthase (TSase) gene for manipulating abiotic stress tolerance in tobacco (Nicotiana tabaccum L.). The expression of the transgene was under the control of two tandem copies of the CaMV35S promoter and was transferred into tobacco by Agrobacterium tumefaciens EHA105. Compared with non-transgenic plants, transgenic plants were able to accumulate high levels of products of trehalose, which were increased up to 2.126-2.556 mg/g FW, although levels were undetectable in non-transgenic plants. This level of trehalose in transgenic plants was 400-fold higher than that of transgenic tobacco plants cotransformed with Escherichia coli TPS and TPP on independent expression cassettes, twofold higher than that of transgenic rice plants transformed with a bifunctional fusion gene (TPSP) of the trehalose-6-phosphate (T-6-P) synthase (TPS) and T-6-P phosphatase (TPP) of E. coli, and 12-fold higher than that of transgenic tobacco plants transformed the yeast TPS1 gene.It has been reported that transgenic plants with E. coli TPS and/or TPP were severely stunted and had morphological alterations of their roots. Interestingly, our transgenic plants have obvious morphological changes, including thick and deep-coloured leaves, but show no growth inhibition; moreover, these morphological changes can restore to normal type in T2 progenies. Trehalose accumulation in 35S-35S:TSase plants resulted in increased tolerance to drought and salt, as shown by the results of tests on drought, salt tolerance, and drought physiological indices, such as water content in excised leaves, malondialdehyde content, chlorophyll a and b contents, and the activity of superoxide dismutase and peroxidase in excised leaves. These results suggest that transgenic plants transformed with the TSase gene can accumulate high levels of trehalose and have enhanced tolerance to drought and salt.     

Improved drought tolerance without undesired side effects in transgenic plants producing trehalose

Most organisms naturally accumulating trehalose upon stress produce the sugar in a two-step process by the action of the enzymes trehalose-6-phosphate synthase (TPS) and trehalose-6-phosphate phosphatase (TPP). Transgenic plants overexpressing TPS have shown enhanced drought tolerance in spite of minute accumulation of trehalose, amounts believed to be too small to provide a protective function. However, overproduction of TPS in plants has also been found combined with pleiotropic growth aberrations. This paper describes three successful strategies to circumvent such growth defects without loosing the improved stress tolerance. First, we introduced into tobacco a double construct carrying the genes TPS1 and TPS2 (encoding TPP) from Saccharomyces cerevisiae. Both genes are regulated by an Arabidopsis RuBisCO promoter from gene AtRbcS1A giving constitutive production of both enzymes. The second strategy involved stress-induced expression by fusing the coding region of ScTPS1 downstream of the drought-inducible Arabidopsis AtRAB18 promoter. In transgenic tobacco plants harbouring genetic constructs with either ScTPS1 alone, or with ScTPS1 and ScTPS2 combined, trehalose biosynthesis was turned on only when the plants experienced stress. The third strategy involved the use of AtRbcS1A promoter together with a transit peptide in front of the coding sequence of ScTPS1, which directed the enzyme to the chloroplasts. This paper confirms that the enhanced drought tolerance depends on unknown ameliorated water retention as the initial water status is the same in control and transgenic plants and demonstrates the influence of expression of heterologous trehalose biosynthesis genes on Arabidopsis root development.     

抗旱相关基因在烟草中的应用研究进展

干旱是影响烟草正常生长、发育、产量和烟叶品质的一个重要逆境因子。在干旱胁迫下,植物体内会通过激发一些抗旱基因的表达来增强植物的抗旱能力。目前,很多抗旱相关的功能蛋白基因和调控蛋白基因已被克隆并在烟草中实现了遗传转化,外源抗旱基因的表达提高了转基因烟草的抗旱能力。抗旱基因的克隆为烟草抗旱新品种的培育奠定了良好的分子基础,系统深入地研究抗旱相关基因在干旱胁迫条件下的表达与调控,可为通过基因工程手段提高烟草的抗旱能力开辟新途径,同时也能为其他农作物的抗旱分子育种和品种改良提供基因资源。     

Effects on Fertility in Transgenic Tobacco by Localized Expression of ipt Gene

The isopenteryl transferase (ipt) gene from Agrobacterium tumefaciens (Smith et Townsend) Conn was driven under the tobacco TA29 promoter and introduced into tobacco ( Nicotiana tabacum L.) plants by A. tumefaciens mediated transformation. PCR and Southern blot analysis confirmed that the ipt gene has integrated into the genomes of tobacco plants. The expression pattern of this chimeric TA29-ipt gene in the transgenic plants was studied, and the endogenous cytokinin level in different organs was assayed by ELISA method. The results showed that the cytokinin content in the androecium of transgenic plants increased 3-4 times as compared with the control, and some changes of the fertility of the TA29-ipt transgenic plants have been observed.     

ipt基因定位表达对转基因烟草育性的影响

杂种优势是生物界的一种普遍现象。作物杂种优势的利用是培育高产、抗逆、优质新品种的重要手段之一。然而 ,常规育种技术获得配套三系的难度很大 ,由此限制了杂种优势利用的发展。近年来应用转基因技术创造雄性不育植株已有不少报道[1- 5] 。有研究表明 ,自然突变的雄性不育株