Acetogenesis from H-2 plus CO2 by spirochetes from termite guts

Pure cultures of termite gut spirochetes were obtained and were shown to ca talyze the synthesis of acetate from H-2 plus CO2. The 16S ribosomal DNA se quences of two strains were 98 percent similar and were affiliated with tho se of the genus Treponema. However, neither was closely related to any know n treponeme. These findings imply an important role for spirochetes in term ite nutrition, help to reconcile the dominance of acetogenesis over methano genesis as an H-2 sink in termite hindguts, suggest that the motility of te rmite gut protozoa by means of attached spirochetes may be based on intersp ecies H-2 transfer, and underscore the importance of termites as a rich res ervoir of novel microbial diversity.