与胡萝卜胚胎发生相关的胚性细胞蛋白63cDNA分离及其基因表达研究

以胡萝卜(Daucus carota L.)鱼雷形胚状体为材料,以λgt10噬菌体为载体,构建了一个含有6.0×10~8个重组子的cDNA文库。用PCR法扩增的长度为1.1kb的胚性细胞蛋白(ECP)63 DNA片段作探针,从cDNA文库中筛选出一个完整的ECP63 cDNA克隆。ECP63 cDNA核苷酸序列总长为1989bp,编码1个含569个氨基酸残基的蛋白质,分子量为62kD。以ECP63 cDNA全长作探针的Northern分子杂交结果表明,ECP63基因在胚性细胞和不同发育时期的胚状体中高度表达,但在幼苗和非胚性细胞中不表达。在转录水平上,ECP63基因在合子胚胎发生后期大量表达。     

肌动蛋白是多头绒泡菌细胞核骨架和染色体骨架的组成成分

自多头绒泡菌(Physarum polycephalum Schw.)的原质团中分离细胞核和染色体,分别经DNaseⅠ消化和2 mol/L NaCl抽提后制备成细胞核骨架和染色体骨架。以抗肌动蛋白的抗体作一抗、FITC标记的羊抗兔IgG抗体作二抗进行的间接免疫荧光实验结果显示,细胞核骨架和染色体骨架都分别与抗体呈阳性反应。间接免疫斑点印迹实验结果进一步证实,细胞核骨架和染色体骨架的蛋白质成分中存在与肌动蛋白抗体呈阳性显色反应的抗原。以抗肌动蛋白的抗体作一抗、金颗粒标记的蛋白A作二抗的间接免疫电镜实验结果表明,在实验组间期细胞核的核仁、集缩染色质和核基质以及中期染色体上都有很多金颗粒分布。上述结果证明,肌动蛋白是多头绒泡菌细胞核和染色体及其骨架的组成成分。     

Electrostatic and hydrophobic interactions governing the interaction and binding of beta-lactoglobulin to membranes

The role of electrostatic and hydrophobic interactions in the binding and penetration of beta-lactoglobulin (betaLG) to preformed lipid membranes was studied using various phospholipid micelles and vesicles. Zwitterionic lysophospholipid micelles are able to induce the beta-sheet to alpha-helix transition, as judged by circular dichroism (CD), but the degree of transition is dramatically below and the amount of lipid required above that for anionic phospholipids with equivalent hydrocarbon chains. Anionic phospholipids with short hydrocarbon chains induce only low alpha-helical content in betaLG as compared to phospholipids with the same head group but longer hydrocarbon chains. These results suggest that both electrostatic and hydrophobic interactions are indispensable in betaLG-lipid interaction. Furthermore, air-water interface monolayer surface pressure and fluorescence anisotropy studies reveal that the membrane insertion of betaLG strongly depends on the nature of phospholipids, given the identical headgroup, particularly lipid packing. These results are supported by urea denaturation and acrylamide fluorescence quenching tests and by the FTIR-ATR polarization results for betaLG in multilayers on a surface. Under the same experimental conditions, the membrane binding and insertion of betaLG as well as the stability of the betaLG-lipid complexes can be enhanced by lowering the pH. Collectively, electrostatic interactions play a crucial role in all the processes involved in the betaLG-lipid interaction, while the presence of hydrophobic interaction remains necessary. Finally, betaLG biological function in the transport of fatty acids was tested by demonstrating the release of 2-AS from a 2-AS-betaLG complex on binding to lipids.     

多头绒泡菌核仁及其骨架中原肌球蛋白的免疫细胞化学鉴定

分离多头绒泡菌(physarum polycephalum)细胞的核仁,先用Dnase I消化,去除核仁内的DNA;然后用025mol/L (NH4)2ＳＯ４和2mol/L NaCl相继抽提去掉大部分蛋白质,制备成核仁骨架。SDSPAGE分析结果表明,核仁骨架中含有约20种多肽,其中包括37kD左右与原肌球蛋白分子量相当的多肽。以兔抗原肌球蛋白抗体为一抗,FITC标记的羊抗兔IgG抗体为二抗的间接免疫荧光检测结果表明,核仁和核仁骨架样品都能发出明亮的荧光,而对照样品未见明亮的荧光。间接免疫斑点印迹检测结果进一步证明,在核仁骨架的蛋白质成分中存在原肌球蛋白。胶体金免疫电镜检测结果显示,标记原肌球蛋白抗体的标本上有较多的金颗粒,而对照组标本上只有极少的金颗粒。金颗粒在核仁中主要呈散在分布。     

Study on Tissue Cultures of Legume Plants

Plant regenerations were achieved from tissue cultures of 31 species of 15 genus of legume plants on A and B media. Various factors including medium composition (major elements, minor element:s, organic components and phytohormones), seed germination rate, illumination and temperature conditions were tested for their effects on callus differentiation in tissue cultures. Combinations of major elements of A or B medium, minor elements and organic components of B5 medium, illumination of 1500–2500 lx, and temperature of 18–27℃ were found suitable for callus differentiation of most legume plants. The calli induced from freshly collected seeds had higher differentiation capacity than from seeds sored for three years. Four types(a,b,c and d) of callus were morphologically distinguished during the differentiation in legume plant tissue cultures. Generally, calli from plants of the same genus belonged to the same type.     

Helical Structure Revealed upon the Condensation and Decondensation of Chromosomes of Vicia faba

By using conventional and stereo electron microscopy, helical structures were revealed in prophase and telophase chromosomes of root tip cells of Vicia faba. Longitudinal and transverse sections of the chromosomes showed that both prophase and telophase chromosomes were composed of chromatin fibres about 0.5μm in diameter and among the 0.5μm chromatin fibre thinner chromatin fibres with a diameter of about 0.2μm were found. In transverse sections, prophase chromosomes appeared to be a circular structure which contained a low electron density centre encircled by the 0.5 μm fibre. In longitudinal section of the chromosomes, the 0.5 μm fibres were seen to be orientated parallel to each other while constituted roughly a right angle to the long axis of the chromosome. Helical coils consisting of the 0.5μm fibre were identified easily by stereo electron microscopy. In transverse sections of telophase chromosomes, both the circular structure similar to that of the prophase chromosomes and the hoof-shaped structure composed of the 0.5μm fibre were observed, demonstrating4 the de-spiralization of the helical coils in the decondensation of the chromosomes. Based on these observations, the radial loop. model and the multiple coiling model are discussed.     

Cell Wall Regenration During Early Development of Mesophyll Protoplasts of Astragalus melilotoides var. tenuis

The techniques of transmission electron microscopy (TEM), electron microscopy (EM) cytochemical visualization of polysaccharide, cell wall flourescence labelling of cell wall and inhibition of wall formation by coumarin treatment were used to explore the cell wall regeneration and its chemical characteristics in mesophyll protoplasts of Astragalus melilotoides var. tenuis. The results showed that after 24 h in culture a number of protruding vesicles, as well as a small amount of fibrillar component were formed on the surface of protoplasts. On day 3, the amount of fibrils increased significantly. On day 5, regenerated primary wall composed of fibrils and granules were observed, in which polysacchaides were detected as result of the periodic acid-silver methenamine reaction. In addition, after 36 h in culture, the protoplasts tended to coalesce, flourescence staining and coumarin treatment demonstrated that the protoplast adhesion was the result of cell wall formation. Based on these data, problems such as the structure of regenerated wall and its chemical nature, etc. were discussed.     

Intergeneric Somatic Hybrid Plants of Nicotiana tabacum L. and Lycium barbarum L. by Protoplast Electrofusion

Mesophyll protoplasts of Nicotiana tabacum L. and protoplasts from cell suspension of Lycium barbarum L. were heterofused by electrofusion with a frequency of ca. 4%--5%. One hundred cell lines were selected at random identified by isozyme analysis with peroxidase and superoxide dismatase, and the differences from their parent were found. Results indicated that 9 cell lines expressed enzymatic bands characteristic of both parents. Five of the 9 cell lines were highly morphogenic and regenerated numerous young shoots that manifested morphological traits specific to both parents. However, these shoots never grew up or regenerate roots. Esterase analysis of leaf material from the regenerants of 5 morphogenic hybrid cell lines demonstrated that two of them (NL4 and NL8) expressed an unique hybrid band which were not shown in either parents. Cytological observation on parental and NL4 hybrid cell lines revealed that the somatic chromosome number of NL4 varied from 58 to 80, significantly higher than that of either parents. Ribosomal DNA analysis of NL4 and NL8 showed that NL8 covered all fragments of both parents: NL4 did not have the fragments characteristic of Lyciurn barbarurn L. Both hybrids had new fragments, suggestive of intermolecular recombination of rDNAs of the parents. Four normal plants morphologically similar to tabacco parent were obtained from hybrid cell hne NL4, which survived after being transferred to soil. Cytological analysis of root-tips from one of the plants indicated that it has ca. 58 chromosomes. This paper also discussed the problems on the production frequency and incompatibility of somatic cell hybrid.     

银杏文献矛盾分析

通过阅读分析近５００篇银杏文献后发现：在银杏（Ｇｉｎｋｇｏｂｉｌｏｂａ）文献中有许多数据和说法等相矛盾的地方,分析了产生矛盾的原因,提出了解决矛盾的建议。     

水杨酸在小麦幼苗渗透胁迫中的作用

用含１．０ｍｍｏｌ／Ｌ ＳＡ的不同渗透势ＰＥＧ溶液漂浮处理小麦幼苗叶片,研究ＳＡ在水分逆境下脂质过氧化中的作用。结果表明,ＳＡ降低了叶片ＣＡＴ活性,轻度渗透胁迫下ＳＡ对稳定膜结构和功能有一定作用。较严重的渗透胁迫加ＳＡ处理使叶片失水量、膜相对透性和ＭＤＡ含量有所增加,Ｈ２Ｏ２和Ｏ２＾－积累较快,但与不加ＳＡ处理比较,ＳＯＤ和ＰＰＯＤ活性仍较高,脂质过氧化程度稍有加重。ＳＡ在诱导植物提高抗逆力中的作