Molecular phylogeny of methanogens associated with flagellated protists inthe gut and with the gut epithelium of termites

The molecular phylogeny of methanogenic archaea associated with the flagell ated protist species Dinenympha and Microjoenia in the gut of termites, Ret iculitermes seperatus and Hodotermopsis sjoestedti, and those attached to t he gut epithelium was examined based on PCR-amplified small-subunit ribosom al RNA genes. The sequences identified were classified into six groups with in the genus Methanobrevibacter, including groups of yet uncharacterized no vel species. Closely related methanogens were shared between Microjoenia an d some Dinenympha cells in each termite. The methanogens harbored by the fl agellates were phylogenetically different from the methanogens associated w ith the gut epithelium, suggesting that distinct methanogen species showed distinct spatial distributions in the termite gut. (C) 2000 Federation of E uropean Microbiological Societies. Published by Elsevier Science B.V. All r ights reserved.