Diversity of 16S rDNA and environmental factor influencing microorganisms in Malan ice core

The research on extrempholic microorganisms in glacial low-temperature environment receives more attention than ever before. Due to the successive chronological records in ice core, it is important to initiate microbiological studies on ice core samples. 23 samples from one ice core,drilled from central Qinghai-Tibetan Plateau, were analyzed.The number of total microorganisms and culturable microorganisms in different layers showed that it related with the content of dust in ice. It is suggested that the distribution of microorganisms in ice depends on the transportation of materials during glacier development. The bacteria diversity in Malan Glacier was analyzed by 16S rDNA sequencing methods, which showed that many sequences were similar to known psychrophilic bacteria.     

番红花及其混淆品的rDNA ITS序列与AS-PCR鉴别

通过对番红花及其混淆品的rDNA ITS区序列进行 PCR 扩增、测序,并运用 Clustal X、Mega 3.0等软件进行序列分析.结果表明番红花 rDNA ITS 区序列全长650 bp,GC百分比为60.3%,与其混淆品的rDNA ITS 区序列存在着显著差异.另外,还设计出了鉴别番红花的位点特异性PCR引物,无需测序即可对番红花及其混淆品进行准确的分子鉴别.     

一株嗜水气单胞菌Aeromonas hydrophila的16S-23S rDNA间区序列分析及应用

根据细菌的16S rDNA 3'端和23S rDNA 5'端的高度保守区设计引物,扩增了一株中华鳖Trionyx sinensis"红板病"病原菌--嗜水气单胞菌的16S-23S rDNA间区,克隆到pGEM-T载体上,测序.用BLAST和DNAstar软件对16S-23S rDNA间区序列以及其内tRNA基因与已发表的嗜水气单胞菌和近缘种的IGSG序列进行比较分析,设计出对嗜水气单胞菌特异的PCR引物,建立了检测嗜水气单胞菌的PCR方法,进行了特异性、灵敏性检测,并用此方法检测了不同的水样.     

几株云南野生隐球酵母菌的分类研究

 对采自云南的8株隐球酵母菌进行了常规方法和26SrDNAD1/D2区域序列分析相结合的分类研究,并确定了这8个菌株的归属.本研究也肯定了该序列分析方法对隐球酵母属的适用性.     

Determination of copy number for 5S rDNA and centromeric sequence RCS2 in rice by Fiber-FISH

The copy number of 5S rDNA and centromeric sequence RCS2 was determined by extended DNA fiber based fluorescence in situ hybridization (Fiber-FISH) in rice (Oryza sativa ssp. indica cv. Guangluai No. 4) genome. In order to determine the copy number, it is necessary to know the basepair number that a given length DNA fiber contains under a microscope. Therefore, the length of two DNA fragments, in which the basepair number had been already known, was measured. The insert sequence of the tested BAC 38D17 was 136 kb and its extended DNA was 56.4 μm long, 2.41 kb/μm on average, while that of the tested BAC 44B4 was 144.5 kb in total and 55.7 μm long, 2.60 kb/μm on average under the microscope. They were very close to the theoretical value of B-DNA in the Watson-Crick DNA model, which is 2.97 kb/μm. According to the average value of basepair number per μm of the two samples mentioned above, that is, 2.51 kb/μm, it could be estimated that the copy number was about 686 for 5S rDNA and 286-1121 for the centromere sequence RCS2.     

22种丝状异型胞固氮蓝细菌的16S rDNA的 PCR-RFLP 分析

用1对引物CYA106F及781R（a）从23种蓝细菌的DNA中扩增出一条600bp的16SrDNA－PCR片段，对该片段进行的限制性酶切长度多态性（RFLP）分析表明：可将其中21种自生或共生的丝状异型胞固氮蓝细菌的样品分为2个类群组，基本上对应于形态分类上的Anabaena及Nostoc属，但有1种被认为是Anabaena的蓝细菌以及作为对照的1种聚球藻(Synechococcus)蓝细菌样品被明显区分出来，并发现Anabaena属的蓝细菌也可同被子植物根乃拉草（Gunnera）形成共生固氮作用。     

半知菌曲霉族真菌胞外多糖的研究Ⅱ:爪哇正青霉胞外多糖化学结构的研究

 经形态鉴定和18srRNA基因组序列分析,编号Ym31794菌株的分类学地位属于半知菌类丛梗孢科曲霉族青霉属丝状真菌,种名爪哇正青霉(Eupenicillium javanicum).该菌发酵液经离心弃菌体,除脂类及乙醇分级提取,分离、纯化的胞外多糖相对分子量为2.6×10⁴,糖的质量分数为89%.真菌胞外多糖经红外光谱(IR),簿层层析(TLC),色质联用(GC-MS),核磁共振(¹³C-NMR,¹H-NMR)等分析可知爪哇正青霉菌胞外多糖为1-6连接的葡萄糖和1-2连接半乳糖构成主干,侧链由1-3连接的甘露糖和1-2连接的葡萄糖构成,结构应为吡喃糖.     

上海地区不同植物根际荧光假单胞菌多样性

荧光假单胞菌是一种常见的植物根际促生细菌,有开发作为生物农药的潜质．以分离自上海周边地区12种植物根际的104株荧光假单胞菌为研究对象,进行了表型分类,并采用16S—rDNARFLP和REP—PCR技术,系统地研究了荧光假单胞菌的遗传多样性．结果表明：16S—rDNARFLP酶切图谱聚类分析在85％相似性水平上,可将供试菌株划分为9群;REP—PCR指纹图谱聚类分析在76％相似性水平上,可将供试菌株划分为26群,说明上海地区的荧光假单胞菌具有丰富的遗传多样性;聚类分析结果还显示出菌株间亲缘关系与其分离地和所在植物具有相关性,表明环境条件对荧光假单胞菌的发育和遗传分化有重要影响．     

锰污染稻田土壤微生物群落结构和遗传多样性研究

采集了湖南省湘潭市锰矿尾渣坝附近受不同程度锰污染的7个水稻田土壤样品,总锰浓度范围为114~4611mg/kg.提取土壤细菌总DNA,用通用引物对其中的16SrDNA进行扩增,然后进行变性梯度凝胶电泳(Denaturing Gradient Gel Electrophoresis),分析长期受锰污染的水稻田土壤微生物群落结构和遗传多样性变化,存在于污染最严重样点中的细菌种群对锰有较高的耐受性,不同锰污染的样点群落结构发生变化并且有菌种的消亡和新菌种的产生.锰污染直接和间接地改变了水稻田土壤微生物群落结构和遗传多样性.     

一株产辅酶Q10的光合细菌菌株的分离及鉴定

从水塘污泥中富集分离到一株产CoQ10含量较高的光合细菌菌株,并对其进行系统鉴定.采用了丙酮作为CoQ10的提取溶剂,样品经超声波破碎后,用紫外分光光度法(UV)作为CoQ10的定性定量方法,成本低且快速,可以作为筛选CoQ10含量较高菌株的方法.以此方法筛选得到菌株LZC,其CoQ10产量为9.49μg/mL菌液.16S rDNA序列系统发育分析表明,菌株LZC在系统进化树上与GenBank中序列号为AB251407.1、AB251408.1、AB017799.1、DQ342322.1的红假单胞菌(红细菌)聚为一族,初步确定菌株LZC为生芽红假单胞菌(Rhodobacter blasticus).菌株LZC至少能稳定传代15次.