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关键词： 马铃薯   Y病毒属病毒   植物互作   分子生物学   系统侵染   抗性  

摘要： 马铃薯Y病毒属 (Potyvirus)是植物病毒中最大的属 ,其基因组为一单链正义RNA ,只包含一个开放阅读框架。基因表达的策略为先将基因组的开放阅读框架翻译成一大的多聚肽 ,再由病毒编码的蛋白酶将其切割成各个小的肽段。表达的产物在病毒的系统侵染、传播、症状表达中起不同的作用。本文综述了该属病毒与寄主植物之间互作的分子生物学基础研究进展 ,并在此基础上就植物对该属病毒的抗病性等方面的研究进展进行了讨论。

关键词： 松属   rDNA   杂种起源   基因组关系   荧光原位杂交   基因组原位杂交（GISH）  

摘要： 被子植物的rRNA基因已经得到深入研究.二倍体被子植物一般拥有1-4对18S-5.8S rRNA位点和1-2对5S rRNA位点.作为特殊的多基因家族成员,rRNA会受均一化力（homogenizing forces）的作用,通过基因转换、不等交换等机制,形成基因的致同进化（concerted evolution）.长期以来,我们一直认为动植物rRNA致同进化水平很高,各种拷贝的序列几乎完全一致,因此可以直接应用PCR测序的方法进行分子系统学研究.但是在裸子植物中由于研究资料的匮乏,使我们对裸子植物rRNA的变异模式了解甚少.松属植物作为裸子植物的最大类群,它们rRNA变异和进化有何特点、与被子植物是否相同,是这个重要类群的进化研究中目前尚未解决的问题.该文的研究内容从三个方面进行：（1）rRNA的染色体定位;（2）5S rRNA的分子进化;（3）杂种基因组研究.

关键词： HIV-1   ICAM-3   ICAM-2   carbohydrates   adhesion   antigen receptor  

摘要： Dendritic cells (DC) are present in essentially every tissue where they operate at the interface of innate and acquired immunity by recognizing pathogens and presenting pathogen-derived peptides to T cells. It is becoming clear that not all C-type lectins on DC serve as antigen receptors recognizing pathogens through carbohydrate structures. The C-type lectin DC-SIGN is unique in that it regulates adhesion processes, such as DC trafficking and T-cell synapse formation, as well as antigen capture. Moreover, even though several C-type lectins have been shown to bind HIV-1, DC-SIGN does not only capture HIV-1 but also protects it in early endosomes allowing HIV-1 transport by DC to lymphoid tissues, where it enhances trans infection of T cells. Here we discuss the carbohydrate/protein recognition profile and other features of DC-SIGN that contribute to the potency of DC to control immunity.

关键词： PHYTOCHROMES   CYTOLOGY  

摘要： Phytochrome signal transduction has in the past often been viewed as being a nonspatially separated linear chain of events. However, through a combination of molecular, genetic and cell biological approaches, it is becoming increasingly evident that phytochrome signalling constitutes a highly ordered multidimensional network of events. The discovery that some phytochromes and signalling intermediates show light-dependent nucleo-cytoplasmic partitioning has not only led to the suggestion that early signalling events take place in the nucleus, but also that subcellular localization patterns most probably represent an important signalling control point. Moreover, detailed characterization of signalling intermediates has demonstrated that various branches of the signalling network are spatially separated and take place in different cellular compartments including the nucleus, cytosol, and chloroplasts. In addition, proteasome-mediated degradation of signalling intermediates most probably act in concert with subcellular partitioning events as an integrated checkpoint. An emerging view from this is that phytochrome signalling is separated into several subcellular organelles and that these are interconnected in order to execute accurate responses to changes in the light environment. By integrating the available data, both at the cellular and subcellular level, we should be able to construct a solid foundation for further dissection of phytochrome signal transduction in plants. (C) New Phytologist (2002) 154: 553-590.

关键词： 烟粉虱   寄主植物   生物学特性   PCR   线粒体DNA   COI基因序列   生物型   系统发育  

摘要： 该论文从以下几方面进行了研究,并取得了初步成果.一、在中国北方首次较系统地调查了烟粉虱的寄主和发生为害情况.该调查基本弄清了在中国北方暴发为害的烟粉虱的偏嗜寄主,对生产实践有一定的指导作用.二、该文在温度为27±1℃、湿度50%～70%和12小时光照条件下,以番茄为寄主植物,研究了烟粉虱的产卵习性、各虫态发育历期、存活率、羽化习性和生物型等生物学特性.三、该文利用mtDNA COI基因片段作标记,采用序列分析的方法,从分子生态学的角度研究了近年来在中国暴发为害的5个烟粉虱种群（北京一品红种群,广州甘蓝种群,西安一品红种群,北京西红柿种群和新疆吐鲁番棉花种群）的生物型.在5个种群的基因片段上,截取与Texas-B型相应的720bp的序列分析.四、该研究设计合成了新引物2819的引物,成功应用于PCR.利用mtDNA COI基因片段作标记,研究了中国17个不同地理区域或寄主的烟粉虱种群.五、对烟粉虱的分子系统学的研究结果表明：在截取的这段序列中,烟粉虱不同种群间的遗传距离从0.25%到26.65%.B型与苏丹种群靠近,遗传距离为5.39%,与其它种群的烟粉虱遗传距离较大（＞12%）;中国福建本地种群CH-FJ与印度种群遗传距离较近为6.71%;中国另一种群HC-China与泰国种群遗传距离较近为0.77%;贝宁种群与其它种群的遗传距离差异最大为19.51%到26.65%.

关键词： foliicolous lichens   Mexico  

摘要： Nine new species of foliicolous lichens are described from Los Tuxtlas Tropical Biology Station, Veracruz, Mexico: Asterothyrium atromarginatum sp. nov. (Asterothyriaceae), Enterographa perez-higaredae sp. nov. (Roccellaceae), Gyalectidium barbatum sp. nov., G. pallidum sp. nov., G. ulloae sp. nov. (Gomphillaceae), Opegrapha heliabravoa sp. nov., O. tuxtlensis sp. nov. (Roccellaceae), Pocsia alvari sp. nov. (Verrucariaceae) and Tricharia sublancicarpa sp. nov. (Gomphillaceae). Pycnidia are reported for the first time in Coenogonium hypophyllum (Vezda) Kalb Lucking. (C) 2002 The British Lichen Society. Published by Elsevier Science Ltd. All rights reserved.

关键词： biodiversity   land use   regeneration niche   seminatural grasslands  

摘要： Pseudorchis albida s.s. is today a rather rare grassland orchid with a declining distribution in Scandinavia, as well as in other parts of Europe. This paper presents (a) ecological site descriptions from 30 Norwegian and Swedish sites, and (b) vegetation analyses from five Swedish populations of the closely related, alpine R straminea, which enable sonic, comparisons between taxa. A Detrended Correspondence Analysis ordination of vegetation data separated sites of P. albida rather well according to their geographical location. The Swedish south-west coast sites were particularly distinct. The Norwegian mid inland region constituted a transition zone between sites from the Norwegian west coast and sites from the Swedish eastern mountains. About 10 vascular plant species form a core group, common to nearly all sites. About 150 species occur in lower total frequencies than 50%. It is concluded that P. albida can occur in a wide array of plant communities. A Kendall correlation matrix for environmental variables for the R albida sites and the site's scores along the three first axes in the DCA ordination showed significant correlations between altitude, soil-pH, grazing, precipitation, mowing, ignition loss, and soil-potassium, with vegetation clusters. (C) 2002 The Linnean Society of London.

关键词： Amino Acid Motifs   Arabidopsis/immunology   Arabidopsis/immunology   Arabidopsis/metabolism   Arabidopsis/metabolism   Arabidopsis/microbiology   Arabidopsis/microbiology   Arabidopsis Proteins/chemistry   Arabidopsis Proteins/metabolism   Bacterial Proteins/chemistry   Bacterial Proteins/metabolism   Carrier Proteins/metabolism   Immunity, Innate   Immunity, Innate   Oryza sativa/immunology   Oryza sativa/immunology   Oryza sativa/microbiology   Oryza sativa/microbiology   Plant Proteins/chemistry   Plant Proteins/metabolism   Protein Binding   Pseudomonas/immunology   Pseudomonas/metabolism   Pseudomonas/physiology  

摘要： Microorganisms that infect plants must suppress their hosts' defence mechanisms before they take up residence. But some plants use molecular guards to sense when they are being manipulated by pathogens.

关键词： Animals   Arabidopsis/genetics   Arabidopsis/genetics   China   Crops, Agricultural/genetics   Food Supply   Genes, Plant/genetics   Genome, Plant   Genomics   Humans   Japan   Japan   Oryza sativa/genetics   Oryza sativa/genetics   Sequence Homology   Switzerland  

摘要： Draft sequences of the rice genome have been produced by two groups. The drafts will be an invaluable resource for research on the genomes of other plants, the cereals in particular.

关键词： 书评   植物生物化学   分子生物学   教科书  

摘要： 二十世纪下半叶，由于分子生物学研究的突飞猛进，使生物科学令人刮目相看，一跃而成为自然科学的带头科学。但值得注意的是植物分子生物学的研究在20世纪80年代以前，一直滞后于其它生物科学的发展。那个时期有人调查，美国大学中许多学生，特别是顶尖私立大学的学生从不愿涉入植物生物学研究。对使用广泛的生物学教科书阅读频率的调查发现，65%的教员不讲授教科书中涉及植物科学的有关章节。但进入20世纪80年代后，这种状况发生了戏剧性的变化，植物分子遗传学取得突破性进展，利用农杆菌取得转基因植物已成为一般实验室的日常操作，拟南芥作为模式植物为植物科学研究提供了意想不到的机会，拟南芥基因组全序列测序的完成更使植物科学如虎添翼，水稻基因组全序列的发表又近在眼前，以上这一切迫使植物科学的教学发生根本性转变，而相应教科书的编写也就迫在眉捷。