高等动植物网格蛋白介导的内吞

主要阐述了网格蛋白、接头蛋白AP2复合体的组成及其功能、动物网格蛋白介导内吞的分子机制和植物网格蛋白介导内吞的一些最新进展;阐述了植物网格蛋白介导的内吞在生长素极性运输、胚胎发育及逆境响应等中的作用,总结了植物网格蛋白介导内吞的生物学意义及展望．     

A mutation that changes cell movement and cell fate in the zebrafish embryo

The study of developmental patterning has been facilitated by the availability of mutations that produce changes in cell fate, in animals such as Caenorhabditis elegans and Drosophila melanogaster. We now describe a zygotic lethal mutation in the zebrafish, Brachydanio rerio, that also changes how particular embryonic cells develop. Severe pattern deficiencies are observed that are restricted to a single body region, the trunk. The mutation may directly affect mesoderm, as somites do not form in the trunk. Head and tail structures, including tail somites, are relatively undisturbed. The earliest detected expression of the mutation is during gastrulation, when movements of mesodermal cells occur incorrectly. We injected prospective trunk mesodermal cells with lineage tracer dye and observed that in mutants these cells may enter a new body region, the tail, and there may express a new fate appropriate for the changed position.     

四川省小檗属植物物种资源及其分布规律研究

经调查研究结果表明，四川小檗属植物共有４０种、５变种．其中７种２变种为四川新分布记录，四川特有植物２种，首次提出四川优势资源植物７种１变种．分析讨论了水平分布与垂直分布规律．水平分布可划归５个自然植被区：川东盆地及盆周山地常绿阔叶林区，川西南山地常绿阔叶林区，川西高山峡谷针叶林区，川西高原针叶林、灌丛、草甸区，川西北高原、高山灌丛、草甸区；垂直分布范围为海拔５００～４０００ｍ，最适生长海拔高度１０００～３０００ｍ．并对资源进行了综合评估，提出了开发利用的有效途径．     

浙江省芳香植物资源的分布及利用

我国芳香植物资源是植物资源的重要组成部分，其开发利用具有较大的潜力较高的经济效益、浙江省的芳香植物资源较为丰富，初步统计，共有７５８种，隶属于８９科、３０６属、分别占浙江省种子植物科、属、种的４８．９％、２４．５％、２２．４％。根据浙江省各地的地理条件及芳香植物的分布规律，将芳香植物资源划分为５个区，分别就其芳香植物的特点和分布进行了探讨，列出了１０种芳香植物作为浙江省芳香植物资源开发利用的重点，     

长核素列连接的曲折线

在正方形图中,建立了八列参量常数为H1,S32,34,36,38;K(=S-H)=12,14;X(=S-2H)=8长核素列之间的连接。这些核素列以核素176 70 34 Yb106 36,124 54 38Xe70 16连接,由坐标K2,S34,36,38;X6,7,X8变换组成一条走向为(6,8)(34,36)(34,8)(36,8)(36,44)(38,44)(38,16)(6,0)(7,0)(35,14)(36,14)(8,0)的迂回折线。     

河南植物区系分布新记录

报道了河南植物区系种子植物1新记录属(Filifolium),4新记录种.     

湘西药用植物分布格局研究

通过调查湘西地区药用植物的地理分布格局及分析其成因,为湘西地区药用植物资源的合理开发和保护提供参考。基于实地考察与相关文献查阅的研究结果表明:热带、亚热带、温带分布型分别占湘西药用植物总数的45.35%,98.55%,43.63%,亚热带分布占绝对优势,温带和热带成分大致相当;在垂直方向上,药用植物分布格局符合植物垂直分布的Rapoport法则,即药用植物种类丰富度呈现出随着海拔升高先增加后降低的现象;在水平方向上,北部县域的药用植物物种多样性高于南部县域。     

Centrosomes direct cell polarity independently of microtubule assembly in C. elegans embryos

Polarity establishment requires a symmetry-breaking event, resulting in an axis along which determinants are segregated. In Caenorhabditis elegans, oocytes are apolar and are triggered to polarize rapidly along one axis after fertilization. The establishment of this first polarity axis is revealed by the asymmetric distribution of PAR proteins and cortical activity in the one-celled embryo. Current evidence suggests that the centrosome-pronucleus complex contributed by the sperm is involved in defining the polarization axis. Here we directly assess the contribution of the centrosome to polarity establishment by laser ablating the centrosome before and during polarization. We find that the centrosome is required to initiate polarity but not to maintain it. Initiation of polarity coincides with the proximity of the centrosome to the cortex and the assembly of pericentriolar material on the immature sperm centrosome. Depletion of microtubules or the microtubule nucleator gamma-tubulin did not affect polarity establishment. These results demonstrate that the centrosome provides an initiating signal that polarizes C. elegans embryos and indicate that this signalling event might be independent of the role of the centrosome as a microtubule nucleator.     

凝固浴中沉淀剂极性对聚丙烯腈聚合物晶粒尺寸分布的影响

通过X射线衍射、溶胀DSC测试研究了凝固浴中沉淀剂极性对PAN聚合物结晶度及晶粒尺寸分布的影响，并采用紫外光谱和流变测试分析了其影响机理。研究结果表明，沉淀剂极性对PAN聚合物晶粒尺寸分布有较大的影响，这种影响是通过沉淀剂分子与PAN分子氰基之间的络合作用实现的；沉淀剂极性越大，这种络合作用越强，对PAN大分子运动能力的束缚作用越明显，PAN聚合物中各晶粒之间的生长速度差异变小，使得PAN聚合物的晶粒尺寸分布变窄。     

Frizzled regulation of Notch signalling polarizes cell fate in the Drosophila eye

The Drosophila eye, a paradigm for epithelial organization, is highly polarized with mirror-image symmetry about the equator. The R3 and R4 photoreceptors in each ommatidium are vital in this polarity; they adopt asymmetrical positions in adult ommatidia and are the site of action for several essential genes. Two such genes are frizzled (fz) and dishevelled (dsh), the products of which are components of a signalling pathway required in R3, and which are thought to be activated by a diffusible signal. Here we show that the transmembrane receptor Notch is required downstream of dsh in R3/R4 for them to adopt distinct fates. By using an enhancer for the Notch target gene Enhancer of split mdelta, we show that Notch becomes activated specifically in R4. We propose that Fz/Dsh promotes activity of the Notch ligand Delta and inhibits Notch receptor activity in R3, creating a difference in Notch signalling capacity between R3 and R4. Subsequent feedback in the Notch pathway ensures that this difference becomes amplified. This interplay between Fz/Dsh and Notch indicates that polarity is established through local comparisons between two cells and explains how a signal from one position (for example, the equator in the eye) could be interpreted by all ommatidia in the field.     

Multiple modes of engrailed regulation in the progression towards cell fate determination

The engrailed gene product of Drosophila specifies the fate of a subset of cells in each segment. Our studies of engrailed regulation suggest that fate determination is an elaborate, multistep process. At the time in embryogenesis when the engrailed-dependent cell fate is probably determined, four modes of control act in an overlapping progression to govern engrailed expression. After activation by pair-rule genes, both an extracellular signal, wingless, and autoregulation are required for engrailed expression. Autoregulation graduates to wingless independence, but is transient, and is superseded by an engrailed-independent mode of maintenance.     

A molecular programme for the specification of germ cell fate in mice

Germ cell fate in mice is induced in proximal epiblast cells by the extra-embryonic ectoderm, and is not acquired through the inheritance of any preformed germ plasm. To determine precisely how germ cells are specified, we performed a genetic screen between single nascent germ cells and their somatic neighbours that share common ancestry. Here we show that fragilis, an interferon-inducible transmembrane protein, marks the onset of germ cell competence, and we propose that through homotypic association, it demarcates germ cells from somatic neighbours. Using single-cell gene expression profiles, we also show that only those cells with the highest expression of fragilis subsequently express stella, a gene that we detected exclusively in lineage-restricted germ cells. The stella positive nascent germ cells exhibit repression of homeobox genes, which may explain their escape from a somatic cell fate and the retention of pluripotency.     

贵州省重点保护植物地理分布的聚类分析

对贵州省重点保护植物的地理分布进行聚类分析,将各种重点保护植物在贵州9个地区分布的有或无作为二元性状,选用Jaccard系数表征各地区间物种组成的相似性,用非加权组对平均法进行聚类。结果表明:重点保护植物分布在省内相邻地区联系紧密;南北、东西地区重点保护植物分布差异明显;重点保护植物分布与省外地区有南北交错渗透现象。     

湖北省苔藓植物资源的研究 I.神农架地区苔藓植物的种类和分布(英文)

报道了位于中国鄂西的神农架地区苔藓植物初步的调查结果．结果表明该地区共有苔藓植物２１６ 种,隶属于 １１４ 属５１ 科． 藓类有１８１ 种,９３ 属,３３ 科,苔类 ３５ 种,２１ 属,１８ 科;其中１２５种是湖北新分布,９ 种为中国特有种