Combinatorial interplay of promoter elements constitutes the minimal determinants for light and developmental control of gene expression in Arabidopsis.

Higher plants are able to integrate environmental and endogenous signals to regulate gene expression for optimal development. To define the minimal sequence requirement sufficient to integrate light and developmental signals in controlling promoter activity, we carried out a systematic analysis of the roles of four well-conserved 'light-responsive elements (LREs)' common to many nuclear-encoded photosynthetic genes. A gain-of-function assay using basal promoter-reporter fusions in stable transgenic Arabidopsis was employed to demonstrate that pairwise combinations of the LREs, but not the individual elements alone, can confer light-inducible expression to the reporter gene independently of the basal promoter context and the light-triggered morphological changes. The activity of the synthetic promoters with the paired LREs can be modulated at least by the phytochrome system. Further, those synthetic light-regulated promoters confer a photosynthetic cell-specific expression pattern and respond to the chloroplast development state. Our data suggest that distinct combinatorial interactions of LREs can serve as minimal autonomous promoter determinants which integrate light and developmental signals and modulate promoter activity.     

腥黑粉菌属一新种

本文报道了从意大利进口兔尾草(Lagurus ovatus L.)上截获的腥黑粉菌属一新种——兔尾草腥黑粉菌(Tilletia laguri G.M.Zhang,G.X.Lin & J.R.Deng),同时讨论了该种与近似种的区别,文中对其形态特征有拉丁文和汉文描述,并附有图片。主模式标本保存在深圳动植物检疫局真菌标本室,等模式标本分别保存在德国蒂宾根大学范基黑粉菌标本馆(HUV)、中国科学院微生物研究所真菌标本室和华南农业大学植保系真菌标本室。     

二核苷酸重复多态性的非同位素检测及其在基因诊断中的应用

本文报道了一种检测二核苷酸重复多态性的简便的非同位素法,利用重复序列两侧的特异引物进行ＰＣＲ扩增,产生的等位片段在薄层变性聚丙烯酰胺凝胶电泳上分离,再用灵敏的银染法显色。该方法不需要标记ＰＣＲ产物,简便、快速,分辨率可达１ｂｐ,并可用多对引物同时进行多重ＰＣＲ分析。用此方法对ＤＭＤ家系成员ｄｙｓｔｒｏｐｈｉｎ基因的５＇－脑型外显子止游区和３＇－非翻译区的两个（ＣＡ）。位点进行了扩增片段长度多态性分     

噬菌体φHAU3的cos位点及其与寄主相互作用的功能位点attP和attB的定位

ＨＡＵ３是寄主范围很广的放线菌噬菌体。Ｓｏｕｔｈｅｒｎ杂交实验表明,ＨＡＵ３可以整合到吸水链霉菌应城变种１０－２２和变铅青链霉菌６６的突变体ＺＸ１的染色体中,形成溶原,其溶原菌自发释放ＨＡＵ３,不受热激和紫外线照射的诱导。通过比较ＨＡＵ３衍生噬粒ｐＩＪ８３００的ＤＮＡ酶切片段在加热前、后电泳带谱的区别,将ＨＡＵ３的ｃｏｓ位点在ｐＩＪ８３００的图谱上得到了定位。还利用Ｓｏｕｔｈｅｒｎ杂交的方法定位了ＨＡＵ３与宿主形成溶原时附着位点（ａｔｔＰ）,并利用脉冲电泳技术定位了在变铅青链霉菌ＺＸ７和吸水链霉菌应城变种１０－２２中形成溶原的附着位点（ａｔｔＢ）。这些信息均有利于以ＨＡＵ３为基础的载体的发展和优化。     

表达HSV－2 gD基因的重组痘苗病毒保护小鼠对抗致死量HSV病霉攻击

利用ＰＣＲ方法对单纯疱疹病毒Ⅱ型糖蛋白Ｄ（ＨＳＶ－２ｇＤ）基因进行了修饰,在其５＇端删去约５００ｂｐ的非编码区,仅保留ＡＴＧ上游７个ｂｐ。将修饰后的ＨＳＶ－２ｇＤ基因插入到带有痘苗病毒天坛株ＴＫ基因区段的痘苗表达质粒ｐＪＳＡ１１７５,置于痘苗病毒Ｐ７．５ｋ早／晚期启动子控制下。将此重组质粒用脂质体Ｌｉｐｏｆｅｃｔｉｎ方法转染已受野型ＴＫ￣＋痘苗病毒天坛株感染的ＴＫ￣－１４３细胞,通过同源重组机制和标志基因ＬａｃＺ产物的蓝斑显色作用,以及ＢｕｄＲ试剂对ＴＫ表型的选择压力,筛选出整合有ＨＳＶ－２ｇＤ基因的重组痘苗病毒。Ｓｏｕｔｈｅｍ杂交表明,ＨＳＶ－２ｇＤ基因已正确地插入痘苗病毒ＴＫ基因区内;间接免疫荧光检测显示,ＨＳＶ－２ｇＤ蛋白已得到有效表达,且主要分布于细胞膜。重组病毒免疫家兔可产生明显的抗ＨＳＶ－２ｇＤ中和抗体。用重组病毒免疫小鼠,３周后可使９４％（１７／１８）的小鼠对抗ＨＳＶ－２的致死量攻击,表明重组病毒具有明显的免疫保护作用。     

酪氨酸羟化酶基因载体－pCMVTH 质粒的构建及在大鼠骨骼肌内的表达

为用转基因方法治疗巴金森氏病大鼠模型,本研究采用分子克隆技术,将合成多巴胺的关键酶－酪氨酸羟化酶（ＴＨ）的基因,克隆进入以巨细胞病毒ＣＭＶ为启动子的载体质粒内,经限制性内切酶定位分析证实该重组的ＤＮＡ质粒的可靠性。携带ＴＨ基因的ＰＣＭＶＴＨ质粒以ＬＩＰＯ－ＦＥＣＴＩＮ介导,在培养的原代骨骼肌细胞中高效表达。本研究为进一步用转基因的细胞植入脑内以治疗巴金森氏病打下一定基础。     

Bi（Ⅲ）与金属硫蛋白作用性质研究

 Ｂｉ（Ⅲ）与金属硫蛋白作用性质研究张保林,黄辉,朱凌燕,岳晟,唐雯霞（南京大学配位化学研究所,配位化学国家重点实验室,南京２１００９３）如何降低顺铂或其它抗癌铂的毒性,一直是癌症化疗中的重要课题之一,最近研究发现预先给大鼠或肺癌病人服用铋盐,可以极大...     

条锈菌侵染初期小麦初生叶内可翻译mRNA的变化

小麦条锈菌毒性小种及其无毒性突变型侵染初期,是不亲和反应的小麦叶片内可翻译ｍＲＮＡ水平迅速增加,而呈亲和反应叶片的增加幅度小且滞后。同时前者的Ｐｏｌｙ（Ａ＋）－ＲＮＡ水平高于未接种对照,后者低于对照。３２Ｐ标记实验证实不亲和反应叶片Ｐｏｌｙ（Ａ＋）－ＲＮＡ的合成增加早于亲和反应叶片。Ｐｏｌｙ（Ａ＋）－ＲＮＡ体外翻译产物经ＳＤＳ－ＰＡＧＥ分离后,放射自显影图谱显示一些多肽条带的３５Ｓ－Ｍｅｔ相对掺入量有定量差异。     

Studies of cell pellets: I. Electrical properties and porosity.

Cell pellets formed by centrifugation provided a good system to study the osmotic behavior, electroporation, and interaction between cells. Rabbit erythrocyte pellets were used in this study because they were simpler than nucleated cells to model analytically. Structurally, cell pellets possessed properties of porous solid bodies and gels. Electrically, cell pellets were shown to behave as a parallel set of resistance, Rp, and capacitance, Cp. Information on pellet structures was obtained from electric measurements. The pellet resistance reflected the intercellular conductivity (porosity and gap conductivity), whereas the pellet capacitance depended mostly on membrane capacitance. The pellet resistance was more sensitive to experimental conditions. The intercellular gap distance can be derived from pellet porosity measurements, providing the cell volume and surface area were known. Rp increased and relaxed exponentially with time when centrifugation started and stopped; the cycles were reversible. When supernatants were exchanged with solutions containing hypotonic electrolytes or macromolecules (such as PEG) after the pellets were formed, complicated responses to different colloidal osmotic effects were observed. A transient decrease followed by a large increase of Rp was observed after the application of a porating electric pulse, as expected from a momentary membrane breakdown, followed by a limited colloidal-osmotic swelling of pelleted cells. The equilibrium values of Rp, Cp, pellet porosity, and intercellular distances were measured and calculated as functions of cell number, centrifugation force, and ionic strength of the exchanged supernatant. Thus, the structure and properties of cell pellets can be completely characterized by electrical measurements.     

Electrically induced fusion of mammalian cells in the presence of polyethylene glycol

Chinese Hamster Ovary (CHO) cells were fused by subjecting cell suspensions to an exponentially decaying electric pulse in the presence of polyethylene glycol (PEG), Dextran or Ficoll. PEG (MW 1,000, 3,350, 8,000, 10,000 and 18,500), Dextran (MW 71,200) and Ficoll (MW 400,000) were added to the pulsing medium. A single exponential electric pulse with peak field strength of 4 kV/cm, and a half-time of 0.72 msec was used. The combination of two techniques, PEG-induced fusion and electrofusion, resulted in highly efficient fusion of CHO cells. Fusion yields (FY) at different concentrations of these polymers were measured using phase-contrast microscopy. FY was highly dependent on the concentration of PEG in media, while the presence of Dextran and Ficoll had no influence on fusion yield. PEG with MW 8,000 was found to be the most effective in causing cell aggregation, and to give the highest FY (40%). An optimal concentration for fusion was found for PEG of each molecular weight. Diluting cells suspended in higher concentrations of PEG to these optimal concentrations after the pulse application regained the optimal FY. It was concluded that PEG-induced prepulse aggregation and moderate cell swelling immediately after the pulse were important factors in achieving high fusion yields.This work is supported by a grant GM-30969 from the National Institutes of Health. Traveling fellowship to N.G.S. was supported from Foundation Cyrill and Methodius and grant N-189 from MCES of Bulgaria.