Ohkuma M, Noda S, Kudo T
Microbiology Laboratory, Institute of Physical and Chemical Research (RIKEN), Saitama, Japan.
FEMS Microbiol Lett. 1999 Feb 15;171(2):147-53. doi: 10.1111/j.1574-6968.1999.tb13425.x.
Termites harbor symbiotic microorganisms in their gut which emit methane. The phylogeny of the termite methanogens was inferred without cultivation based on nucleotide sequences of PCR-amplified 16S ribosomal RNA genes. Seven methanogen sequences from four termite species were newly isolated, and together with those previously published, these sequences were phylogenetically compared. The termite methanogen sequences were divided into three clusters. Two clusters of sequences, derived from the gut DNA of so-called higher termites, were related to methanogens in the orders Methanosarcinales or Methanomicrobiales. All of the sequences in the case of lower termites were closely related to the genus Methanobrevibacter. However, most of the termite symbionts were found to be distinct from known methanogens. They are not dispersed among diverse methanogen species, but rather formed unique lineages in the phylogenetic trees.
白蚁肠道内栖息着能产生甲烷的共生微生物。基于聚合酶链式反应（PCR）扩增的16S核糖体RNA基因的核苷酸序列，在未进行培养的情况下推断出了白蚁产甲烷菌的系统发育。新分离出了来自四种白蚁物种的七个产甲烷菌序列，并将其与之前发表的序列进行了系统发育比较。白蚁产甲烷菌序列分为三个簇。来自所谓高等白蚁肠道DNA的两个序列簇与甲烷八叠球菌目或甲烷微菌目的产甲烷菌有关。在低等白蚁的情况下，所有序列都与短柄甲烷杆菌属密切相关。然而，大多数白蚁共生菌被发现与已知的产甲烷菌不同。它们并非分散在不同的产甲烷菌物种中，而是在系统发育树中形成了独特的谱系。
