| Introducing Hongoh Laboratory |
| More than 99% of the earth’s microbial species are currently unculturable and their physiology and ecology remain largely unknown. Armed with the key words ‘environment’ and ‘symbiosis’ and the tools of molecular biology, we at Hongoh Laboratory are attempting to fill in the gaps of this black hole of knowledge. |
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| Most of the microbial species in our environment are difficult to culture. In order to find out about their actual circumstances we need to study their molecular diversity and then conduct fluorescent in situ hybridization (FISH) on the target sequences. Figure 1 shows how FISH analysis reveals that 70% of the uncultured intestinal bacteria of the Formosan subterranean termite are symbiotic bacteria living within the cells of the protists that digest the wood in the termite’s gut. |
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(Figure 1)
Formosan subterranean termite (left);
intestinal symbiotic protist (upper right);
bacteria co-existing inside the protist cell; |
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| After conducting structural analysis of a microbial community, we will use metagenomice analysis to study the function of the community as a single entity and single cell genomics to study the function of individual unculturable species within the community. The latter, in particular, is a topic at the front-line of technological development. Figure 2 gives an example of how whole genome amplification from a few cells is used to completely decode the genome of the symbiotic bacteria shown in figure 1, thus explaining how the bacteria function. |
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(Figure 2)
Nitrogen fixation and recycling in unculturable symbiotic bacteria as revealed with genome analysis;
these functions are essential for the Formosan subterranean termite, which eats only nitrogen-deficient wood, and the protists living in its gut. |
| Most recent publications |
| 1) |
Hongoh Y. et al. (2008) Genome of an endosymbiont coupling N2 fixation to celluloysis within protist cells in termite gut. Science 322, 1108-1109. |
| 2) |
Hongoh Y. et al. (2008) Complete genome of the uncultured Termite Group 1 bacteria in a single host protist cell. Proc. Natl. Acad. Sci. USA 105,5555-5560 |
| 3) |
Hongoh Y. et al. (2006) Intracolony variation of bacterial gut microbiota among castes and ages in the fungus-grouwing termite Macrotermes gilvus. Mol. Ecol. 15, 505-516 |
