线虫(Caenorhabditis elegans)受精卵中细胞极性的建立

早期线虫胚胎提供了一个研究发育过程的极佳模型。线虫胚胎的第一次分裂是不对称的,产生的两个子细胞在尺度的大小和发育命运上均有不同,而这些不同是由第一次有丝分裂周期中胞质决定子的不均匀分布造成的。通常相信,在受精过程中,精子所携带的中心体介导了对极性建成至关重要的胞质流动的产生。同时,细胞骨架成分被认为参与了胞质成分的定位事件。关于par基因的研究目前进展迅速,大多数par基因的突变都导致了线虫早期胚胎分裂不对称性的丧失。     

秀丽隐杆线虫(Caenorhabditis elegans)在药物筛选中的应用

基于靶点的体外药物筛选操作相对简单,成本较低,但是由于药物在体内的作用并不仅仅取决于其与靶点的作用程度,吸收、分布、代谢、排泄特征和毒性均会对早期先导物能否进入临床使用产生极大的影响,因此,药物的体内筛选受到重视。本文重点综述了秀丽隐杆线虫（C.elegans）在抗衰老、抗感染药物筛选中的应用情况。秀丽隐杆线虫结构简单、易于培养和可实现高通量筛选,在未来的药物筛选中必将发挥更重要的作用。     

水稻基因组测序的研究进展

水稻是最重要的粮食作物之一,世界上大约有一半的人口以水稻为主要粮食。作为基因组研究的模式植物,水稻基因组的测序工作已在世界范围内展开。此项研究工作不仅能破译水稻全基因组序列,还将有助于了解其他禾本科植物的基因组信息。本对水稻基因组测序工作进展作一综述。     

模式线虫中国新纪录种Caenorhabditis elegans的种类鉴定与系统分析

广杆属秀丽线虫Caenorhabditis elegans是生物学中应用广泛的经典模式生物,利用形态准确对其进行种类鉴定困难且耗时,实验利用NGM培养基对1000余份样品进行线虫的分离培养,通过形态学、分子生物学、系统学分析及生殖隔离验证等方法对所分离线虫进行鉴定和分析,得到4个种共55个品系的广杆属线虫,其中采自武汉植物园腐殖质土壤的GXW0001经鉴定为C.elegans的中国分布新纪录。研究为模式线虫种类鉴定建立了系统可靠的方法,并填补了我国模式线虫种质资源库的空白。     

植物基因组比较作图研究进展

基因组比较作图是基因组研究的重要内容。植物比较作图研究表明,在长期的进化过程中,基因的组成表现出高度的保守性。随着植物遗传图谱和物理图谱的迅速发展,为植物比较作图奠定了重要的基础。现就植物基因组遗传图和物理图以及比较作图的最新研究进展作一介绍。     

植物基因组表达序列标签(EST)计划研究进展

植物表达序列标签(EST)计划是随机挑选cDNA克隆,并对其3′或5′端进行大规模一次性测序,将得到的150～500 bp长度的DNA片段与数据库中的序列进行比较,获得对基因组结构、组织、表达等认识的基因组研究策略.就近年来国际植物EST计划的实施情况、植物EST计划的研究范围、生物信息学在EST研究中的应用、EST数据库及查询、植物EST研究中遇到的问题等方面内容进行了综述.     

水稻基因组测序的研究进展

水稻是最重要的粮食作物之一,世界上大约有一半的人口以水稻为主要粮食.作为基因组研究的模式植物,水稻基因组的测序工作已在世界范围内展开.此项研究工作不仅能破译水稻全基因组序列,还将有助于了解其他禾本科植物的基因组信息.本文对水稻基因组测序工作进展作一综述。 Abstract:Because of the importamce of rice as the staple food source for over half of the world population and since rice is a leading model plant for genomic studies,an international effort has now begun to sequence the rice genome.This project eventually will reveal all of the genomic sequence information of rice and be an indispensable aid in understanding the genomics of other grass species.In this paper,the development and research progress in sequencing of rice genome are reviewed.     

食线虫真菌基因组测序和分析研究进展

食线虫真菌作为线虫的天敌,是一种潜在的线虫病害的生防制剂。食线虫真菌通过形成特殊的捕食器官或产生粘性孢子和毒素等方式捕捉和侵染线虫。近年来,随着测序技术的进步和生物信息学的应用,越来越多真菌基因组已经被测定和报道。目前,已经有7种食线虫真菌的基因组被报道,包括捕食线虫真菌寡孢节丛孢(Arthrobotrys oligospora)、线虫卵寄生真菌厚垣普可尼亚菌(Pochonia chlamydosporia)和内寄生真菌明尼苏达被毛孢(Hirsutella minnesotensis)等。本文对食线虫真菌的基因组特点、毒力相关基因家族的扩张、捕食器官形成调控和进化机制进行了系统地总结,对组学时代食线虫真菌研究面临的关键问题进行了评述。     

中华卵索线虫线粒体基因组多态性分析

为完善昆虫病原索科线虫线粒体基因组全序列数据库, 更系统地研究其基因组特征和系统演化规律, 进而为发挥该线虫生防潜力打下基础, 我们开展了中华卵索线虫Ovomermis sinensis线粒体全基因组的研究。该研究通过线粒体基因组滚环复制及酶切图谱, 揭示了中华卵索线虫线粒体基因组具有种内遗传多态性, 即群体中单体线虫具有独特的酶切条带, 且条带累加之和变化范围较大, 为16.5～24.5 kb。为进一步了解线粒体基因组多态性特征及产生的分子机制, 采用两步长PCR方法对2条代表性成虫线粒体基因组进行了测序及拼接, 得其全长分别为18 864和16 777 bp。对这2条序列的比对表明, 线粒体基因组中位于ND2和ND4之间的可变区域, 不仅基因排列顺序不同, 且存在ND3基因重复现象, 这是导致中华卵索线虫线粒体基因组呈现多态性的主要原因。通过对以上研究结果的分析及与GenBank中已有的6种索科线虫线粒体基因组序列进行比对, 概括出其线粒体基因组基本特点: ①线粒体基因排列顺序各不相同;②部分线虫线粒体基因存在重复现象, 且重复次数不同;③线粒体基因组大小存在很大差异。     

小线虫,大发现:Caenorhabditis elegans在生命科学研究中的重要贡献

自20世纪60年代开始,秀丽线虫作为重要的模式生物在生命科学的发展过程中发挥着举足轻重的作用。线虫中的许多重大发现为人们理解复杂的细胞生命活动做出了极大的贡献。本文对秀丽线虫的研究历史、重要成果及研究前景作一简要综述。     

VIG-1 is required for maintenance of genome stability in Caenorhabditis elegans

To explore the function of VIG-1 in Caenorhabditis elegans, we analyzed the phenotypes of two vig-1 deletion mutants: vig-1(tm3383) and vig-1(ok2536). Both vig-1 mutants exhibited phenotypes associated with genome instability, such as a high incidence of males (Him) and increased embryonic lethality. These phenotypes became more evident in succeeding generations, implying that the germline of vig-1 accumulates DNA damage over generations. To examine whether vig-1 causes a defect in the DNA damage response, we treated worms with UV or camptothecin, a specific topoisomerase I inhibitor. We observed that the embryonic survival of the vig-1 mutants was reduced compared with that of the wild-type worms. Our results thus suggest that VIG-1 is required for maintaining genome stability in response to endogenous and exogenous genotoxic stresses.     

Phylogenetics in Caenorhabditis elegans: an analysis of divergence and outcrossing

This study establishes a phylogenetic framework for the natural geographic isolates of the widely studied nematode species Caenorhabditis elegans. Virtually complete mitochondrial genomes are sequenced from 27 C. elegans natural isolates to characterize mitochondrial divergence patterns and to investigate the evolutionary history of the C. elegans hermaphrodite lineages. Phylogenetic analysis of mitochondrial sequences reveals the presence of two major C. elegans hermaphrodite clades (designated clade I and clade II). Fifty-six nuclear loci, widely distributed across the five autosomes and the X chromosome, are also analyzed in a subset of the C. elegans isolates to evaluate nuclear divergence patterns and the extent of mating between different strains. A comparison of the phylogenetic tree derived from mitochondrial data with the phylogenetic tree derived from nuclear data reveals only one inconsistency in the distribution of isolates into clades I and II, suggesting that mating between divergent C. elegans strains is an infrequent event in the wild.     

Caenorhabditis elegans functional genomics: omic resonance.

The nematode Caenorhabditis elegans is widely used as a model organism for studying many fundamental aspects of development and cell biology, including processes underlying human disease. The genome of C. elegans encodes over 19,000 protein-coding genes and hundreds of non-coding RNAs. The availability of whole genome sequence has facilitated the development of high throughput techniques for elucidating the function of individual genes and gene products. Furthermore, attempts can now be made to integrate these substantial functional genomics data collections and to understand at a global level how the flow of genomic information that is at the core of the central dogma leads to the development of a multicellular organism.     

秀丽隐杆线虫在高校遗传学实验中的应用

秀丽隐杆线虫(Caenorhabditiselegans)是模式生物中的重要成员之一,因其实验成本低,实验周期短,非常适宜用于高校的遗传学实验教学中。线虫在实验教学中的使用,一方面可以有效地丰富高校实验教学的内容,另一方面也可以很好地激发学生的学习兴趣。本文介绍了线虫在遗传学实验教学中的应用实例,如生活周期观察、单因子杂交、单核苷酸多态性研究、RNA干扰(RNAi)实验等;对实验设置、操作要求、实验相关准备工作等进行了较为细致的描述,为线虫在高校遗传学实验教学中的应用提供了详实案例,可为线虫在高校遗传学实验或其他相关实验课程如细胞生物学实验、模式生物与发育生物学实验中的应用提供参考。     

Genetic variation for outcrossing among Caenorhabditis elegans isolates

The evolution of breeding systems results from the existence of genetic variation and selective forces favoring different outcrossing rates. In this study we determine the extent of genetic variation for characters directly related to outcrossing, such as male frequency, male mating ability, and male reproductive success, in several wild isolates of the nematode Caenorhabditis elegans. This species is characterized by an androdioecious breeding system in which males occur with hermaphrodites that can either self-fertilize or outcross with males. We find genetic variation for all characters measured, but also find that environmental variation is a large fraction of the total phenotypic variance. We further determine the existence of substantial genetic variation for population competitive performance in several laboratory environments. However, these measures are uncorrelated with outcrossing characters. The data presented here contribute to an understanding of male maintenance in natural populations through their role in outcrossing.     

Multiple Molecular Forms of Acetylcholinesterase in the Nematode Caenorhabditis elegans

Abstract: Extracts of the nematode Caenorhabditis elegans contain five molecular forms of acetylcholinesterase (AChE) activity that can be separated by a combination of selective solubilization, velocity sedimentation, and ion-exchange chromatography. These are called form IA (5.2s), form IB (4.9.s), form II (6.7s), form III (11.3s), and form IV (13.0s). All except form III are present in significant amounts in rapidly prepared extracts and are probably native; form III is probably derived autolytically from form IV. Most of forms IA and IB can be solubilized by repeated extractions without detergent, whereas forms II, III, and IV require detergent for effective solubilization and may therefore be membrane-bound. High salt concentrations are not required for, and do not aid in, the solubilization of these forms. For all forms, molecular weights and frictional ratios have been estimated by a combination of gel permeation chromatography and velocity sedimentations in both H₂O and D₂O. The molecular weight estimates range from 83,000 to 357,000 and only form II shows extensive asymmetry. The separated forms have been characterized with respect to substrate affinity, substrate specificity, inhibitor sensitivity, thermal inactivation, and detergent sensitivity. Judging by these properties, C. elegans is like other invertebrates in that none of its cholinesterase forms resembles either the “true” or the “pseudo” cholinesterase of vertebrates. However, internal comparison of the C. elegans forms clearly distinguishes forms IA, III, and IV as a group from forms IB and II; the former are therefore designated “class A” forms, the latter “class B” forms. Genetic evidence indicates that separate genes control class A and class B forms, and that these two classes overlap functionally. Several factors, including kinetic properties, molecular asymmetry, molecular size, and solubility, all suggest that a molecular model of the multiple cholinesterase forms observed in vertebrate electric organs probably does not apply in C. elegans. Potential functional roles and subunit structures of the multiple AChE forms within each C. elegans class are discussed.     

A liquid-based method for the assessment of bacterial pathogenicity using the nematode Caenorhabditis elegans

Caenorhabditis elegans has previously been used as an alternative to mammalian models of infection with bacterial pathogens. We have developed a liquid-based assay to measure the effect of bacteria on the feeding ability of C. elegans. Using this assay we have shown that Pseudomonas aeruginosa strain PA14, Burkholderia pseudomallei and Yersinia pestis were able to inhibit feeding of C. elegans strain N2. An increase in sensitivity of the assay was achieved by using C. elegans mutant phm-2, in place of the wild-type strain. Using this assay,P. aeruginosa PA01 inhibited the feeding of C. elegans mutant phm-2. Such liquid-based feeding assays are ideally suited to the high-throughput screening of mutants of bacterial pathogens.     

马基因组研究进展

各种生物都具有其独特的遗传信息, 深入了解生物体的形成过程以及各种生命活动都离不开基因组的研究成果。由于在世界范围内马具有良好的健康情况记录和详细的系谱记录, 使得马成为生命科学研究中极具价值的模式动物。尽管起步较晚, 但在过去的几年中, 马基因组图谱经历了前所未有的发展。文章主要对近年来马基因组遗传图谱、物理图谱、基因组比较作图以及功能基因组学等研究进展进行了综述, 这些图谱也正是世界各地研究人员用以探寻与马的各种性状(包括全部的健康状况、抗病性能、生殖生育能力、运动性能以及诸如毛色这样的表型特征等)相关基因的重要工具。相信这些研究成果将为马匹疾病预防、诊断和治疗提供新的思路与方法, 并将为马遗传育种提供更好的选配依据。     

细菌与秀丽隐杆线虫之间互作关系的研究进展

秀丽隐杆线虫(Caenorhabditis elegans)以其个体小、易培养、生活周期短等优势成为生物发育、衰老、神经及免疫相关机制研究的模式生物.它在实验室培养时主要靠饲喂大肠杆菌OP50,有报道,细菌及其代谢物对线虫的代谢、行为和寿命有至关重要的影响.因此,作为一个遗传模型,秀丽隐杆线虫可以帮助研究微生物与宿主相...