Termites have a well-noted ability to digest and absorb cellulose, a main component of wood. The intestines of termites are home to microorganisms, including protista and bacteria, that have been known for some time to be related to the breakdown of cellulose. However, most of these microorganisms are difficult to culture, so the mechanism by which they break down cellulose had not been elucidated.
This study overcame that obstacle and succeeded in mapping the complete genome of Rs-D17, a bacteria that lives in the cells of Trichonympha (T. agilis), a protist inhabiting the intestine of the Japanese subterranean termite.
Mapping of a complete genome requires the accumulation of massive amounts of single strand genomes. However, because T. agilis is divided into many strands, the collected symbiotic Rs-D17 also tend to be multi-strand genomes. There are no examples of successful isolation and culture, moreover, so obtaining large volumes of single strands by culturing was impossible.
Rs-D17, a gut microbe isolated from the termite species Reticulitermes speratus (top left). Within the gut (top right) of the termite is a thriving ecosystem of microbial species (lower left). The Rs-D17 bacterium can be seen leaking out of a gut protist cell in which it resides (lower right). (C) 2008 National Academy of Sciences of the United States of America
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