小麦原胚对外源大分子与不透膜物质的摄入

为检验小麦原胚基端特定位点上的外连丝型胞间连丝和开放孔道在摄取外源物质上的作用,以不透膜的阳离子铁蛋白(cationized ferritin)和萤黄(lucifer yellow CH )为示踪物,对其吸入与传布动态进行了荧光与电子显微镜观察。结果表明,这两种物质确可以以非跨膜运输的方式沿着原胚基端的特定通道进入原胚细胞。     

Silencing the type II sodium channel gene: a model for neural-specific gene regulation.

Neural-specific expression of a sodium channel mini-gene has been shown to be mediated by a 28 bp silencer element, RE1, located in the 5' flanking region of the gene. This element is active exclusively in cell lines that do not express the endogenous brain type II sodium channel gene, including fibroblast, skeletal muscle, and certain neuronal cell lines. All of these non-type II expressing cells contain RE1-binding complexes. On the basis of mutational analysis and in vivo "repressor trap" experiments, we propose that cell-specific RE1-binding proteins are responsible, at least in part, for restricting expression of the type II sodium channel gene to specific neurons in the vertebrate nervous system.     

Characterization of the antigenic domains of the major core protein (p26) of equine infectious anemia virus.

A panel of recombinant trpLE-gag fusion proteins and synthetic peptides was used in Western immunoblot and enzyme-linked immunosorbent assays to identify segments of the major core protein (p26) of equine infectious anemia virus that are antigenic in horses during experimental and natural infections with the virus. The predominant humoral immune response was directed toward a highly immunogenic domain composed of 83 amino acids from the carboxy terminus of p26. The observed immunogenicity of p26 resembled that reported for p24 of human immunodeficiency virus type 1, suggesting the conservation of structural motifs in the lentiviral core proteins which are responsible for their observed immunogenicity during persistent lentivirus infections.     

Induction by Electric Currents of Ethylene Biosynthesis in Cucumber (Cucumis sativus L.) Fruit

The effects of an electric current on ethylene biosynthesis were investigated in cucumber (Cucumis sativus L.) fruit that were producing almost no ethylene. Direct currents at 0.5 to 3.0 milliamperes induced much ethylene synthesis, with a rapid continuous increase in the rate, which reached a peak within 5 to 6 hours and then decreased. The rate of production was greater with a stronger current. Ethylene production was not observed after the use of a sine-wave alternating current (60 hertz) at 3 milliamperes, the magnitude at which a direct current had the greatest effect. The activity of 1-aminocyclopropane-1-carboxylic acid (ACC) synthase and ethylene forming enzyme (EFE) increased before the rise in ethylene production. ACC synthase and EFE were activated sixfold and fourfold, respectively, by 2 hours. The concentration of ACC increased linearly up to 6 hours and then decreased. Ethylene induction by an electric current was suppressed almost completely by the infiltration of the cucumbers with 5 millimolar aminooxyacetic acid, an inhibitor of ACC synthase, and was also suppressed 70% by 5 millimolar salicylic acid, an inhibitor of EFE. The results indicate that the ethylene induced by the direct current was synthesized via the ACC-ethylene pathway as a result of electrical stress, a new kind of stress to be identified.     

松辽盆地阿尔必期微体浮游植物新属种

该文描述了松辽盆地中白垩世阿尔必期泉头组三段的微体浮游植物化石1新属7新种,隶属于微咸水沟鞭藻类2属5新种(含4新亚种),淡水绿藻1属1种和疑源类1新属1新种。并对沟鞭藻 Ngktericysta Bint,1986进行了修订。     

松辽盆地白垩纪微体浮游植物群及其环境讨论

该文报道了松辽盆地白垩纪丰富的非海相微体浮游植物群,主要是沟鞭藻类及一些绿藻和疑源类;论述了藻类的生物地层特征,自下而上初步划分出10个组合带;结合微量元素和古地磁等资料,较详细地讨论了含微体浮游植物组段的沉积环境,认为松辽盆地在白垩纪至少遭受过两次重要的海侵(分别在青山口组一段及嫩江组一、二段沉积时期),导致古松辽湖泊五种不同水体环境的演替,指出微体浮游植物组合的变化是受古盐度、古温度和古水深等因素控制的。此外,对有关组段的地质时代也进行了讨论,进一步补充了新的浮游植物化石证据。     

表达甲型肝炎病毒抗原的重组痘苗病毒(VMS11 HAV25)的免疫原性

甲型肝炎(甲肝)病毒基因全部开放读码框架cDNA重组于痘苗病毒天坛株DNA的HindⅢM片段,获得了重组痘苗病毒VMS11HAV25。用10~7PFU或10~8PFU病毒量皮内免疫家兔,能诱生甲肝病毒抗体,其滴度与免疫剂量、免疫次数及间隔有关。组织培养中和试验表明,该抗体具有中和甲肝病毒的能力。VMS11HAV25的免疫效果似优于本实验室已报道的另一株甲肝病毒基因重组于TK区的重组痘苗病毒Re41。     

碳谱在甙结构测定中的应用

本文以齐墩果烷型五环三萜皂甙为例,较为详细地总结归纳了~(13)C-NMR谱在糖的数目,构型、构象、连结位置以及糖链数目等方面的应用规律,以及~(13)C-NMR谱在甙键稳定性、糖的连接顺序等方面的研究概况。     

稻米垩白形成的气象生态基础研究

在全国13个点、19个品种多播期试验基础上,对稻米垩自形成的气象生态基础进行了分析。结果表明,水稻齐穗后15天的日均温是影响稻米垩白大小的主要气象因子。经对稻米垩白与齐穗后15天内均温关系的动态分析可知,稻米垩白随该时段温度提高而增大的拐点温度约为29℃(品种间略有差异),接近或超过该点温度,稻米垩白会突发性地增加。