Keeling P J, Poulsen N, McFadden G I
Plant Cell Biology Research Centre, Parkville, VIC, Australia.
J Eukaryot Microbiol. 1998 Nov-Dec;45(6):643-50. doi: 10.1111/j.1550-7408.1998.tb04561.x.
The phylogenetic diversity of parabasalian flagellates from termite hindguts has been examined by small subunit ribosomal RNA (rRNA) amplification and sequencing. Two species of particular interest, the giant trichomonad Pseudotrypanosoma giganteum and the hypermastigote Trichonympha magna, were isolated from the gut of Porotermes adamsoni by micropipetting, and the rRNA genes from these small populations amplified and sequenced. rRNA genes representing Hypermastigida and the Trichomonadida families Devescovinidae and Trichomonadidae, were also recovered by amplification from whole hindguts of three termites, P. adamsoni, Cryptotermes brevis, and Cryptotermes dudleyi. The parabasalian rRNA genes from C. brevis were found to comprise a unique and extremely heterogeneous lineage with no clear affinities to any known parabasalian rRNAs. In addition, one of the sequences isolated from P. adamsoni was found to be similar to another uncharacterised rRNA gene from Reticulitermes flavipes. The phylogeny of all known parabasalian small subunit rRNAs was examined with these new sequences. We find many taxonomic groups to be supported by rRNA, but not all. We have found the root of parabasalia to be very difficult to discern accurately, but have nevertheless identified several possible positions.
通过小亚基核糖体RNA（rRNA）扩增和测序，对来自白蚁后肠的副基体鞭毛虫的系统发育多样性进行了研究。从亚当森原白蚁肠道中通过微量移液器分离出两种特别有趣的物种，巨型毛滴虫巨拟锥虫和超鞭毛虫大披发虫，并对这些小群体的rRNA基因进行扩增和测序。还通过从三种白蚁（亚当森原白蚁、短鼻木白蚁和达德利木白蚁）的整个后肠中扩增，获得了代表超鞭毛虫目以及滴虫科德韦斯科维科和滴虫科的rRNA基因。发现短鼻木白蚁的副基体rRNA基因构成了一个独特且极其多样的谱系，与任何已知的副基体rRNA没有明显的亲缘关系。此外，从亚当森原白蚁中分离出的一个序列被发现与来自黄胸散白蚁的另一个未表征的rRNA基因相似。利用这些新序列研究了所有已知的副基体小亚基rRNA的系统发育。我们发现许多分类群得到了rRNA的支持，但并非全部。我们发现副基体的根很难准确辨别，但尽管如此，还是确定了几个可能的位置。
