New taxonomy of methanogens based on the analysis of lipid component parts

1979年Balch等人发表了基于rRNA寡核苷酸编目法的产甲烷菌分类方法，由于已有资料的产甲烷菌种类中有近80%是在此之后分离的，因此我们在新建立的脂质组分分析的基础上，对产甲烷菌的分类进行了从级到属的重新研究。在科或属水平上，产甲烷菌类群间脂质组分的分布具有特异性。产甲烷菌科（Methanosacinaceae）和产甲烷菌科（Methanomicrobiaceae）的脂质成分差异很大，足以将这两个科重新划分为两个单独的目。也就是说，应该提出一个新订单。同样地，我们应该提出甲烷球菌科是超嗜热甲烷球菌（Mco）的一个新科。Jannaschii和Mco。igneus。Methanosaeta属的嗜热种与中温种的脂质成分不同，这表明这两个物种应该属于单独的属。该方法最近被应用于日本产甲烷菌的鉴定。

Because almost 80% of the methanogen species known to data were isolated after 1979 when Balch et al published methanogen taxonomy based on rRNA oligonucleotide cataloging method, the taxonomy of methanogens were reexaminned at order to genus levels on the basis of the lipid component parts analysis newly developed by us. The distribution of lipid component parts among methanogen groups was found to be specific to taxa at a family or genus level. The differences in the lipid components between methanogens of the families Methanosacinaceae and Methanomicrobiaceae were great enough to reclassify these two families into two separate orders. That is, a news order Methanosarcinales should be proposed. Similarly it should be proposed that Methanocaldococcaceae is a new family for the hyperthermophilic methanococci, Mco. Jannaschii and Mco. igneus. Thermophilic species of the genus Methanosaeta was found to be different in their lipid component parts from the mesophilic species of the genus, suggesting that both species should fall into separate genera. This method was applied to identification of methanogens isolated in Japan recently.