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Analysis and application of the 16S-23S rRNA intergenic spacers in mycoplasmas

支原体16S-23S rRNA基因间隔区的分析及应用

基本信息

批准号：
07660398
负责人：
HARASAWA Ryo
金额：
$ 1.79万
依托单位：
University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07660398/
关键词：
Mycoplasma Mollicutes 16S rRNA

项目摘要

Mycoplasmas (class Molicutes) are consisting of group of the smallest prokaryotes known that are able to grow in cell-free media, lack a cell wall, and have very small genomes with a low G+C content. Members of the genus Mycoplasma are ubiquitous in nature, and their hosts range from plants to animals. The phylogenetic analyzes of the Mycoplasma species largely depends on the 16S rRNA sequence. On the basis of the 16S rRNA sequence anlysis, the genus Mycoplasma is divided into five clsters, M.mycoides group, M.pneumoniae group, M.hyorhinis group, M.hominis group, and M.fermentans group. The genes coding for rRNA molecules of mycoplasmas are organized in operons and arranged in the order of 5'-16S-23S-5S-3', in which the individual rRNA genes are separated by internal transcribed spacer (ITS) regions. Mycoplasmas have only one or two operons for the rRNA genes. The ITS regions between the 16S and 23S rRNA genes have been shown to lack tRNA genes and to be variable in seqence and length depending on the Mycoplasma species. In this study we sequenced and analyzed the mycoplasmal ITS region between the 16S and 23S rRNA genes as an alternative to 16S rRNA,because recent studies indicate the ITS can be used as chronometers for determining the relationships of genetically closely related species, as they have higher rates of divergence than 16S rRNA genes. Our previous studies on the genus Ureaplasma indicated that the phylogenetic relationships derived from the 16S rRNA and ITS sequences are almost identical.

支原体（分子类）由一组已知的最小原核生物组成，它们能够在无细胞培养基中生长，缺乏细胞壁，并且具有非常小的基因组和低 G+C 含量。支原体属的成员在自然界中普遍存在，其宿主范围从植物到动物。支原体物种的系统发育分析很大程度上取决于 16S rRNA 序列。根据16S rRNA序列分析，支原体属分为五个类：蕈状支原体组、肺炎支原体组、猪鼻支原体组、人型支原体组和发酵支原体组。编码支原体rRNA分子的基因以操纵子组织并按5'-16S-23S-5S-3'的顺序排列，其中各个rRNA基因由内部转录间隔区（ITS）分隔。支原体只有一两个 rRNA 基因操纵子。 16S 和 23S rRNA 基因之间的 ITS 区域已被证明缺乏 tRNA 基因，并且序列和长度随支原体种类的不同而变化。在这项研究中，我们对16S和23S rRNA基因之间的支原体ITS区域进行了测序和分析，作为16S rRNA的替代品，因为最近的研究表明ITS可以用作确定遗传上密切相关的物种关系的计时器，因为它们比16S rRNA基因具有更高的分化率。我们之前对解脲支原体属的研究表明，16S rRNA 和 ITS 序列的系统发育关系几乎相同。