用分子生物学技术对草菇进行菌株鉴别

利用ＡＰ－ＰＣＲ和ＲＡＰＤ技术对三个草菇菌株进行鉴别,其结果与用草菇菌株Ｖ３４基因文库中的中等重复序列为探针进行限制性内切酶长度多态性分析（ＲＦＬＰ）,及对编码核糖体５．８ＳｒＲＮＡ的ＤＮＡ（ｒＤＮＡ）进行ＰＣＲ扩增后的产物进行限制性内切酶长主多态性分析（ＰＣＲ－ＲＦＬＰ）的结果相一致。这一结果显示出用这四种方法对草菇菌株进行鉴别具有相似的效果。同时用这四种方法构建的分子生物学标记显示出这三个菌株     

常用实验用近交系小鼠粒体ＤＮＡ遗传变异的分析

应用ＰＣＲ－ＲＦＬＰ和ＰＣＲ－ＳＳＣＰ技术,研究了分析了国内常用的实验用近交系小鼠线粒体ＤＮＡ（mtＤＮＡ）的品种间遗传变异。ＰＣＲ－ＲＦＬＰ分析发现,小鼠mtＤＮＡ的Ｄ－loop、tRNA^Met Glu Ile及ＮＤ３基因核酸序列,在４６个限制性内切酶酶切位点上均无差异;用ＰＣＲ－ＳＳＣＰ分析方法对这些小鼠mtＤＮＡ的高变异区Ｄ－Loop的５′及3′端作进一步分析,亦未发现品种间遗传变异。结合mtＤＮＡ具有的母系遗传方式的特点,这一结果提示：常用的实验用近交系小鼠形成中可能只有１种雌性血统起了作用。     

RAPD技术及其在微生物学方面的应用

198 0年 ,Ｂｏｔｓｅｉｎ提出ＤＮＡ限制性片段长度多态性 (ＲＦＬＰ)可以作为遗传标记 ,从此开创了直接应用ＤＮＡ多态的新阶段。 80年代后 ,ＤＮＡ多聚酶链式反应 (ＰＣＲ)的发展 ,使直接扩增ＤＮＡ的多态性成为可能 ,并在此基础上产生了许多种新型分子标记 ,诸如扩增片段多态性 (ＡＬＦＲ)、串联重复序列(ＶＮＴＲ)、单链构型多态性 (ＰＣＲ ＳＳＣＰ)、序列特异扩增区域 (ＳＣＡＲ)、随机扩增多态性ＤＮＡ(ＲＡＰＤ)等。而ＲＡＰＤ是较为突出的一种。ＲＡＰＤ是由Ｗｉｌｌｉａｍｓ和Ｗｅｌｓｈ在 1 990年各自独立发现的一种ＤＮＡ多态检…     

应用PCR-SSCP快速鉴定结核分枝杆菌复合群

通过聚合酶链反应（ＰＣＲ）－单链构象多态性（ＳＳＣＰ）技术分析结核分枝杆菌和非结核分枝杆菌临床株的１６ＳｒＤＮＡ基因。６０例临床标本中,２０例为阳性,与传统方法比较无差异。其中分型：１８例为结核分枝杆菌,２例为结核分枝杆菌和非结核分枝杆菌双重感染。２０例阴性标本中,ＰＣＲ－ＳＳＣＰ又检查出５例阳性。２０例对照标本中,３种传统方法与ＰＣＲ－ＳＳＣＰ法均检测为阴性。全部试验３ｄ报告结果。结核分枝杆菌复合群和卡介苗的图形相同以外,其它分枝杆菌的ＰＣＲ－ＳＳＣＰ电泳图谱均有差异。所以,应用ＰＣＲ－ＳＳＣＰ技术快速     

小卫星区域MS31A等位基因特异MVR—PCR分析

用等位基因特异ＭＶＲ－ＰＣＲ技术能够对小卫星区域ＭＳ３１Ａ（Ｄ７Ｓ２１位点）位基因结构的多态性进行分析,在法医学个体识别上具有极其重要的作用。对１００名中国人无关个体ＭＤ３１Ａ５’端侧翼ＤＮＡ多态性进行分析,获得了其不同等位基因的频率和单倍体型的分布,结果表明８１．８％的 ＤＮＡ样品能够用等位基因特异ＭＶＲ－ＰＣＲ分析。     

中国人r——干扰素cDNA在大肠杆菌中的高效表达

应用ＲＴ－ＰＣＲ技术从中国人淋巴细胞ｍＲＮＡ反转录产物中克隆了ＩＦＮ－ｒ－ｃＤＮＡ,序列分析证实了分子进化规律对ＩＦＮ－ｒｃＤＮＡ序列存在多态性的推论。在此基础上应用ＤＮＡ重组技术,将去信号肽中国人ＩＦＮ－ｒ ｃＤＮＡ克隆到原核表达质粒ｐＢＶ２２０ ＰＲＰＬ启动子下游,转化大肠杆菌ＤＨ５ａ,通过温度诱导表达,成功地在大肠杆菌中稳定、高效地表达了中国人ＩＦＮ－ｒ ｃＤＮＡ,其表达水平占全菌可溶性总     

人碱性成纤维细胞生长因子基因克隆,cDNA5‘端修饰及在大 …

采用ｃＤＮＡ－ＰＣＲ技术,从人胎盘ｃＤＮＡ文库ＤＮＡ中克隆了人碱性成纤维在子（ｈｂＦＧＦ）基因,用ＰＣＲ突变法对其５＆端序列进行修饰,奖天然和修饰后的ｈｂＦＧＦ基因分别克隆至表达载体ｐＢＶ２２１,免疫抑迹和ＳＤＳ－ＰＡＧＥ结果证明,经修饰后的基因在大肠杆菌ＤＳ５α中获得了表达,表达量占菌体总蛋白９％。     

新疆地区盐湖的中度嗜盐菌的16S rDNA PCR—RFLP分析

对来自新疆地区艾丁湖、艾比湖和玛那斯盐湖等盐湖的２８株中度嗜盐菌与９株相关的参比菌株,进行了１６Ｓ ｒＤＮＡ ＰＣＲ－ＲＦＬＰ分析,这些菌株是革兰氏阴性杆菌,能在０～２５％ＮａＣｌ中生长。在实验中,选用４种限制性内切酶ＡｌｕⅠ、ＨｉｎｆⅠ、ＲｓａⅠ和ＨａｅⅢ,将供试菌株的１６Ｓ ｒＤＮＡ的ＰＣＲ产物进行酶切,用３％的琼脂糖电泳分析酶切产物。结果表明,在７４％的相似性水平上分为３群。群Ⅰ包括新分离的     

两个根瘤菌新群的系统发育学分析

在数值分类、ＳＤＳＰＡＧＥ 全细胞蛋白分析、ＤＮＡＤＮＡ 杂交、１６ＳｒＤＮＡＰＣＲＲＦＬＰ 的基础上,测定了两个分离自干旱地区苜蓿、草木樨根瘤菌新群１ 、２ 的中心株ＸＪ９６０６０ 、ＸＪ９６４０８ 的１６ＳｒＤＮＡ 全序列,并进一步将中心株和３１ 株已知菌、３ 株分自黄土高原的根瘤菌进行了系统发育学分析。结果表明,供试菌株在系统发育树中基本分成Ｓｉｎｏｒｈｉｚｏｂｉｕｍ 、Ｍｅｓｏｒｈｉｚｏｂｉｕｍ 、ＡｇｒｏｂａｃｔｅｒｉｕｍＲｈｉｚｏｂｉｕｍ 、Ｒｈｉｚｏｂｉｕ ｍ 、Ｂｒａｄｙｒｈｉｚｏｂｉｕｍ 、Ａｚｏｒｈｉｚｏｂｉｕｍ 六个分枝。群１ ,２ 落入Ｓｉｎｏｒｈｉｚｏｂｉｕ ｍ 分枝。     

人白介素6受体功能区片段在E.coli中的表达

通过ＤＮＡ体外重组技术,以ｐＥＴ－３ｂ为表达载体,构建了重组表达质粒ｐＥＴ－６Ｒ（Ｂ）和ＰＥＴ－６Ｒ（Ｂ）４,分别编码２８ｋＤ和ｈＩＬ－６Ｒ配基结合区片段及其５３ｋＤ的二联体蛋白,并为酶切分析和ＤＮＡ序列分析所证实,ＳＤＳ－ＰＡＧＥ分析表明,含有重组表达质粒的菌株可分别表达出２８ｋＤ的蛋白ｒＩＬ６Ｒ－２８和５３ｋＤ的ｒＩＬ６Ｒ－５３重组蛋白分别占菌体总蛋白的４５％和２９％左右,重组蛋白主要包涵体形     

An insight into the genetic variation of Schistosoma japonicum in mainland China using DNA microsatellite markers

This study presents the first microsatellite investigation into the level of genetic variation among Schistosoma japonicum from different geographical origins. S. japonicum isolates were obtained from seven endemic provinces across mainland China: Zhejiang (Jiashan County), Anhui (Guichi County), Jiangxi (Yongxiu County), Hubei (Wuhan County), Hunan (Yueyang area), Sichuan 1 (Maoshan County), Sichuan 2 (Tianquan County), Yunnan (Dali County), and also one province in the Philippines (Sorsogon). DNA from 20 individuals from each origin were screened against 11 recently isolated and characterized S. japonicum microsatellites, and a set of nine loci were selected based on their polymorphic information content. High levels of polymorphism were obtained between and within population samples, with Chinese and Philippine strains appearing to follow different lineages, and with distinct branching between provinces. Moreover, across mainland China, genotype clustering appeared to be related to habitat type and/or intermediate host morph. These results highlight the suitability of microsatellites for population genetic studies of S. japonicum and suggest that there may be different strains of S. japonicum circulating in mainland China.     

Distinct Genetic Diversity of Oncomelania hupensis,Intermediate Host of Schistosoma japonicum in Mainland China as Revealed by ITS Sequences

Background

Oncomelania hupensis is the unique intermediate host of Schistosoma japonicum, which causes schistosomiasis endemic in the Far East, and especially in mainland China. O. hupensis largely determines the parasite''s geographical range. How O. hupensis''s genetic diversity is distributed geographically in mainland China has never been well examined with DNA sequence data.

Methodology/Principal Findings

In this study we investigate the genetic variation among O. hupensis from different geographical origins using the combined complete internal transcribed spacer 1 (ITS1) and ITS2 regions of nuclear ribosomal DNA. 165 O. hupensis isolates were obtained in 29 localities from 7 provinces across mainland China: lake/marshland and hill regions in Anhui, Hubei, Hunan, Jiangxi and Jiangsu provinces, located along the middle and lower reaches of Yangtze River, and mountainous regions in Sichuan and Yunnan provinces. Phylogenetic and haplotype network analyses showed distinct genetic diversity and no shared haplotypes between populations from lake/marshland regions of the middle and lower reaches of the Yangtze River and populations from mountainous regions of Sichuan and Yunnan provinces. The genetic distance between these two groups is up to 0.81 based on Fst, and branch time was estimated as 2–6 Ma. As revealed in the phylogenetic tree, snails from Sichuan and Yunnan provinces were also clustered separately. Geographical separation appears to be an important factor accounting for the diversification of the two groups of O. hupensis in mainland China, and probably for the separate clades between snails from Sichuan and Yunnan provinces. In lake/marshland and hill regions along the middle and lower reaches of the Yangtze River, three clades were identified in the phylogenetic tree, but without any obvious clustering of snails from different provinces.

Conclusions

O. hupensis in mainland China may have considerable genetic diversity, and a more complex population structure than expected. It will be of significant importance to consider the genetic diversity of O. hupensis when assessing co-evolutionary interactions with S. japonicum.     

Determination of genetic diversity among Indian isolates of Rhizoctonia bataticola causing dry root rot of chickpea

Genetic diversity among 27 isolates (23 from chickpea and 4 from other host crops) of Rhizoctonia bataticola representing 11 different states of India was determined by random amplified polymorphic DNA (RAPD), internal transcribed spacer restriction fragment length polymorphism (ITS-RFLP) and ITS sequencing. The isolates showed variability in virulence test. Unweighted paired group method with arithmetic average cluster analysis was used to group the isolates into distinct clusters. The clusters generated by RAPD grouped all the isolates into six categories at 40% genetic similarity. High level of diversity was observed among the isolates of different as well as same state. Some of the RAPD (OPN 4, OPN 12, and OPN 20) markers clearly distinguished majority of the isolates into the area specific groups. The ITS I, 5.8rDNA and ITS II regions of 11 isolates representing different RAPD groups were amplified with primers ITS 1 and ITS 4 and digested with seven restriction enzymes. The restriction enzymes DraI, MboI, RsaI, and AluI were found to be suitable for differentiating the isolates into five categories by showing isolate specific ITS-RFLP patterns. The isolates were variable in their nucleotide sequences of the ITS regions. This is the first study on genetic diversity among chickpea isolates of R. bataticola.     

CONSPECIFICITY AND INDO-PACIFIC DISTRIBUTION OF SYMBIODINIUM GENOTYPES (DINOPHYCEAE) FROM GIANT CLAMS

We previously reported the occurrence of genetically‐diverse symbiotic dinoflagellates (zooxanthellae) within and between 7 giant clam species (Tridacnidae) from the Philippines based on the algal isolates' allozyme and random amplified polymorphic DNA (RAPD) patterns. We also reported that these isolates all belong to clade A of the Symbiodinium phylogeny with identical 18S rDNA sequences. Here we extend the genetic characterization of Symbiodinium isolates from giant clams and propose that they are conspecific. We used the combined DNA sequences of the internal transcribed spacer (ITS)1, 5.8S rDNA, and ITS2 regions (rDNA‐ITS region) because the ITS1 and ITS2 regions evolve faster than 18S rDNA and have been shown to be useful in distinguishing strains of other dinoflagellates. DGGE of the most variable segment of the rDNA‐ITS region, ITS1, from clonal representatives of clades A, B, and C showed minimal intragenomic variation. The rDNA‐ITS region shows similar phylogenetic relationships between Symbiodinium isolates from symbiotic bivalves and some cnidarians as does 18S rDNA, and that there are not many different clade A species or strains among cultured zooxanthellae (CZ) from giant clams. The CZ from giant clams had virtually identical sequences, with only a single nucleotide difference in the ITS2 region separating two groups of isolates. These data suggest that there is one CZ species and perhaps two CZ strains, each CZ strain containing individuals that have diverse allozyme and RAPD genotypes. The CZ isolated from giant clams from different areas in the Philippines (21 isolates, 7 clam species), the Australian Great Barrier Reef (1 isolate, 1 clam species), Palau (8 isolates, 7 clam species), and Okinawa, Japan (1 isolate, 1 clam species) shared the same rDNA‐ITS sequences. Furthermore, analysis of fresh isolates from giant clams collected from these geographical areas shows that these bivalves also host indistinguishable clade C symbionts. These data demonstrate that conspecific Symbiodinium genotypes, particularly clade A symbionts, are distributed in giant clams throughout the Indo‐Pacific.     

Phylogenetic analysis of Piscirickettsia salmonis by 16S, internal transcribed spacer (ITS) and 23S ribosomal DNA sequencing

Piscirickettsia salmonis, the etiologic agent of piscirickettsiosis, is a systemic disease of salmonid fish. Variations in virulence and mortality have been observed during epizootics at different geographical regions and in laboratory experiments with isolates from these different locations. This raises the possibility that biogeographical patterns of genetic variation might be a significant factor with this disease. To assess the genetic variability the 16S ribosomal DNA, the internal transcribed spacer (ITS) and the 23S ribosomal DNA of isolates from 3 different hosts and 3 geographic origins were amplified using the polymerase chain reaction (PCR). Results of this analysis confirm that P. salmonis is a member of the gamma subgroup of the Proteobacteria and show that the isolates form a tight monophyletic cluster with 16S rDNA similarities ranging from 99.7 to 98.5%. The ITS regions were 309 base pairs (bp), did not contain tRNA genes, and varied between isolates (95.2 to 99.7% similarity). Two-thirds of the 23S rRNA gene was sequenced from 5 of the isolates, yielding similarities ranging from 97.9 to 99.8%. Phylogenetic trees were constructed based on the 16S rDNA, ITS and 23S rDNA sequence data and compared. The trees were topologically similar, suggesting that the 3 types of molecules provided similar phylogenetic information. Five of the isolates are closely related (> 99.4% 16S rDNA similarity, 99.1% to 99.7% ITS and 99.3 to 99.8% 23S rDNA similarities). The sequence of one Chilean isolate, EM-90, was unique, with 16S rDNA similarities to the other isolates ranging from 98.5 to 98.9%, the ITS from 95.2 to 96.9% and the 23S rDNA from 97.6 to 98.5%.     

大豆疫霉根腐病菌的rDNA ITS序列分析

采用真菌核糖体基因转录间隔区(ITS)通用引物,PCR扩增了大豆疫霉根腐病菌具有差异的17个菌株的ITSI与ITS2,经过与DL2000的标准分子量DNA进行比较,得到了大约800~1000bp左右的片段,并对PCR产物进行了序列测定。以USA为外类群利用最大简约法构建了大豆疫霉根腐病菌的系统发生树,并分析了菌株之间的遗传进化关系。结果表明:不同菌株ITS1和ITS2在碱基构成上有很大差异,17个菌株大致分为4个谱系中,且来自于同一地区的菌株大都分布在同一谱系中,显示出地理上的差异。     

Random Amplified Polymorphic DNA and Polymerase Chain Reaction Markers for the Differentiation and Detection of Stenocarpella maydis in Maize Seeds

The genetic relationship of 34 isolates of Stenocarpella maydis from different geographic regions in South Africa was analysed by random amplified polymorphic DNA (RAPD) and ribosomal DNA markers. Two genetic groups were differentiated by using three RAPD primers and correlated to the cultural morphology of the isolates. Of all the isolates tested, 79.4% were clustered into RAPD group I (RG I), which did not sporulate when cultured on potato dextrose agar (PDA) at 25°C for 10 days. The rest of the isolates designated as RG II sporulated on PDA medium and showed a higher genetic variation. Ribosomal DNA (rDNA) was amplified using polymerase chain reaction (PCR) with the universal primers, internal transcribed spacer (ITS) 1 and ITS 4. Restriction digestion of PCR products displayed three types (RF A, RF B and RF C) of profiles. RF A was in accordance with RG I. RF B was consistent with RG II except for one isolate, U5. However, U5 displayed a unique profile and had no restriction sites for Hpa II and Hae III. The results indicate that two distinct genetic groups exist among S. maydis isolates from maize in S. Africa. The ITS1 and ITS2 regions of rDNA were sequenced and primers were designed. The designed primer pair P1/P2 permitted a sensitive and specific detection of S. maydis .     

PCR-based identification of individuals of Schistosoma japonicum representing different subpopulations using a genetic marker in mitochondrial DNA.

A mitochondrial NADH dehydrogenase I gene fragment (NDI) was sequenced for three laboratory maintained isolates of Schistosoma japonicum. Comparison of sequences representing the isolates (originally obtained from the Anhui and Zhejiang provinces of the People's Republic of China, and from the Philippines) revealed inter-isolate sequence variations of 0.2-0.6% and no intra-isolate variation was found. The sequences also indicated that while the amplification products of the Zhejiang and Philippine isolates contained a recognition site for the endonuclease RsaI, there was no such site in the Anhui isolate. This was tested by digesting amplification products from a number of individual worms with RsaI. Then an infection experiment was designed to test the value of this genetic marker for studies of the population biology of S. japonicum in the final host. For this, the two Chinese isolates were used. Three groups of mice (A-C) were exposed firstly to a primary infection and then challenge-infected at weeks 4 and 7 of the experiment. In group A the first infection was done with the Anhui isolate, and the two others with the Zhejiang isolate, thereby providing a specific, detectable cohort. In groups B and C the Anhui isolate was used for the second and third infection. All mice were perfused 5 weeks after the last challenge infection, and the NDI was subsequently amplified from DNA of the perfused worms and digested with RsaI. The digestion revealed that while infection groups A and B contained mixed populations of the Anhui and Zhejiang isolates, only Zhejiang worms were present in group C. We concluded that the absence/presence of the RsaI site in the NDI provides a useful marker for the delineation of cohorts of S. japonicum.     

Analysis of genomic diversity among photosynthetic stem-nodulating rhizobial strains from northeast Argentina

The genomic diversity among photosynthetic rhizobia from northeast Argentina was assessed. Forty six isolates obtained from naturally occurring stem and root nodules of Aeschynomene rudis plants were analyzed by three molecular typing methods with different levels of taxonomic resolution: repetitive sequence-based PCR (rep-PCR) genomic fingerprinting with BOX and REP primers, amplified 16S rDNA restriction analysis (ARDRA), and 16S-23S rDNA intergenic spacer-restriction fragment length polymorphism (IGS-RFLP) analysis. The in vivo absorption spectra of membranes of strains were similar in the near infrared region with peaks at 870 and 800 nm revealing the presence of light harvesting complex I, bacteriochlorophyll-binding polypeptides (LHI-Bchl complex). After extraction with acetone-methanol the spectra differed in the visible part displaying peaks belonging to canthaxanthin or spirilloxanthin as the main carotenoid complement. The genotypic characterization by rep-PCR revealed a high level of genomic diversity among the isolates and almost all the photosynthetic ones have identical ARDRA patterns and fell into one cluster different from Bradyrhizobium japonicum and Bradyrhizobium elkanii. In the combined analysis of ARDRA and rep-PCR fingerprints, 7 clusters were found including most of the isolates. Five of those contained only photosynthetic isolates; all canthaxanthin-containing strains grouped in one cluster, most of the other photosynthetic isolates were grouped in a second large cluster, while the remaining three clusters contained a few strains. The other two clusters comprising reference strains of B. japonicum and B. elkanii, respectively. The IGS-RFLP analysis produced similar clustering for almost all the strains. The 16S rRNA gene sequence of one representative isolate was determined and the DNA sequence analysis confirmed the position of photosynthetic rhizobia in a distinct phylogenetic group within the Bradyrhizobium rDNA cluster.     

中药乌头及其近缘种的rDNA—ITS序列分析

运用PCR扩增产物直接测序的方法对云南、安徽的乌头及其近缘种植物的ITS区碱基序列测定。表明核糖体DNA中ITS区的完整序列（包括ITS1,ITS2和5．8s）,4种乌头属植物的ITS1序列长度为249bp,云南鸟头和安徽乌头及黄山鸟头ITS2序列长度为189bp,赣皖乌头ITS2序列长度为217bp。运用Mega2软件进行系统分析得到系统进化树。ITS序列特征是乌头鉴别的有效分子标记。