小眼高原鳅线粒体DNA的酶切分析

用4种限制性内切酶对小眼高原鳅进行了线粒体DNA的酶切分析，共检测出7个酶切位点，发现EcoRI一种酶切类型具有多态性。     

A comparison of morphology,pathogenicity and restriction fragment patterns of mitochondrial DNA among isolates of Phytophthora porri Foister

Thirteen strains ofPhytophthora porri from five different hosts were compared with respect to their morphology, cardinal temperatures for growth, pathogenicity to leek and cabbage and restriction fragment patterns of mitochondrial DNA. Morphology of vegetative growth was rather similar in most isolates. Those characters which differed among isolates showed overlapping variability and could not be used to distinguish groups, with the exception of production of oogonia and sporangia and the antheridium type. Considerable differences were found in restriction patterns of mitochondrial DNA, isolates from the same host mostly showing identical patterns. Isolates from differentAllium species showed relatively similar restriction patterns if compared to the other isolates. Isolates fromBrassica oleracea proved to be a homogeneous group, quite different from the others with respect to restriction patterns, production of sporangia, production of oogonia, antheridium type and pathogenicity. One isolate, CBS 366.59, isolated from and pathogenic toA. porrum, deviated in many characters from the other isolates. It showed the restriction patterns ofPhytophthora nicotianae and also the high cardinal temperatures for growth typical for this species. The sporangia, however, were distinctly non-papillate and the majority of antheridia was of the paragynous type.     

Frankia菌遗传多样性的rDNAIGS RFLP研究

Frankia是一类能与非豆科树木共生结瘤固氮的放线菌。关于其属的分类目前比较确认 ,对于种水平的划分 ,虽然从可溶性蛋白类型 (张道海等 ,1 991 ;Bensonetal.,1 983;Gardesetal.,1 987a)、同功酶类型(Gardesetal.,1 987b ;张道海等 ,1 989)、脂肪酸 (Weeleretal.,1 986)、血清 (Bakeretal.,1 981 ;孙慧君等 ,1 991 )、宿主特异性 (Baker,1 987;Torreyetal.,1 989)、DNA同源性 (Fermamdexetal.,1 989;Akimovetal.,1 992 )、基因组 (Dobritsa ,1 985 )和质粒的限制酶切图谱 (Simonetetal.,1 985 )等诸多方面进行了分析 ,但由于研究的菌株数量有限 ,且培养过程中菌株的生物学特性易发生变异 ,因而迄今为止仍没有一种有效的种的分类方法。近年来 ,1 6SrDNA及其 1 6S～ 2 3SrDNA间隔序列作为一个分子标记 ,广泛应用于各种微生物的分子遗传差异和分类鉴定研究 (韦革宏等 ,1 999;冯瑞华 ,2...     

应用RFLP定位水稻的生育期基因

选用水稻RFLP图谱上的45个DNA随机克隆结合4种限制性内切酶,分析了广亲和品种Pecos,测验种秋光和南京11之间的多态性,发现其中15个探针能在这3个品种间检测到多态性。进一步用14个多态性探针和形态标记色素原基因C分析三交群体Pecos/南京11//秋光中标记与抽穗日数的共分离。结果表明：三交群体各单株抽穗期人布为双峰，早抽穗     

组培品种黑珍米与供体的形态差异及其RFLP分析

由水稻组织培养后代选育的品种黑珍米与亲本Ｂａｓｍａｔｉ ３７０相比，其形态性状，如株高、每穗总数粒，穗长，单株有效穗数，千粒重和生育期等发生了显著变化；并且使原来的白稃尖和白谷壳变成了紫稃尖和紫色谷壳。应用分布于１２条水稻染色体的１２１个ＤＮＡ探针分析黑珍米与其亲本的ＲＦＬＰ，结果表明：有２４．８％的探针检测到了多态性，分布于１０条染色体。结合４种限制性内切酶（ＥｃｏＲＩ，ＢａｍＨＩ，ＨｉｎｄⅢ和     

用SSR标记提高水稻分子连锁图谱密度

本课题组利用圭630／台湾粳的DH群体，建立了一个水稻RFLP连锁图。该图谱含175个标记，总长1224．6cM，相邻标记间平均距离为7．0cM。但该图标记分布不够均匀，存在较多空白区，且在第4和第8染色体上分别存在一个断点。本研究试图在原有RFLP图谱的基础上，添加一些SSR标记，以使该图谱标记更加密集和均匀，并消除两个断点。共筛选了361对RM引物，获得了183对多态标记，在12条染色体上共整合了57个RM标记，染色体连锁图总长度为1811．2cM，比原图谱增长了47．9％，相邻标记间平均距离为7．8cM，与原图谱相近。不过，两条染色体上的两个断点仍无法消除，暗示这两个断点区域多态性较低或重组率较高。     

Differential diagnosis of dog hookworms based on PCR-RFLP from the ITS region of their rDNA

Species of Ancylostoma infecting dogs and sometimes humans are sympatric in many parts of the world. The establishment of a specific molecular diagnostic tool is important, not only to refine information for epidemiological studies, but also to evaluate the efficacy of vaccine programmes and assist in the development of specific drug treatments. The ITS region from 20 specimens of A. braziliense, collected from three separate geographical areas of Brazil, and from 10 specimens of A. caninum, collected from the same area in Brazil were sequenced and analyzed. Alignment of sequences showed that this gene is highly conserved. The intraspecific polymorphism for both species was less then 1%, whereas the interspecific polymorphism was 6.2, 7.3 and 9.4% between A. ceylanicum and A. braziliense; A. caninum and A. ceylanicum and A. ceylanicum and A. braziliense, respectively. Among the three species it was 12.3%. This revealed the ITS region as highly conserved and consequently a good molecular marker for diagnostic studies. In this work, four restriction enzymes were used in a PCR-RFLP using the ITS region of rDNA, to establish a differential diagnosis which discriminates between three Ancylostoma species, A. braziliense, A. caninum and A. ceylanicum. The best pattern was given by the HinfI enzyme, which produced different fragment sizes for each of the three species. Furthermore, the diagnostic tool differentiates DNA extracted directly from faeces of Ancylostoma-infected dogs.     

基于16S rDNA序列和RFLP分析的病鳗分离菌株鉴定

结合16S rDNA基因序列和限制性片段长度多态性（RFLP）的分析方法,通过与GenBank库中已递交的细菌16S rDNA基因序列进行同源性比较,对分离自发病鳗鲡（欧洲鳗鲡,日本鳗鲡和美洲鳗鲡）的30株细菌进行初步鉴定和分类.结果表明,这些细菌可大致分为气单胞菌属（Aeromonas sp.）、假单胞菌属（Pseudomonas sp.）、邻单胞菌属（Plesiomonas sp.）、克雷伯氏菌属（Klebsiella sp.）、柠檬酸杆菌属（Citrobacter sp.）、不动杆菌属（Acinetobacter sp.）和肠杆菌属（Enterobacter sp.）等7个菌属.分析认为,部分分离菌株可能是引起鳗鲡病害的疑似致病性菌株.