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Published June 29, 2001 | public
Journal Article

Nitrogen Fixation by Symbiotic and Free-Living Spirochetes

Abstract

Spirochetes from termite hindguts and freshwater sediments possessed homologs of a nitrogenase gene (nifH) and exhibited nitrogenase activity, a previously unrecognized metabolic capability in spirochetes. Fixation of 15-dinitrogen was demonstrated with termite gut Treponema ZAS-9 and free-living Spirochaeta aurantia. Homologs of nifH were also present in human oral and bovine ruminal treponemes. Results implicate spirochetes in the nitrogen nutrition of termites, whose food is typically low in nitrogen, and in global nitrogen cycling. These results also proffer spirochetes as a likely origin of certain nifHs observed in termite guts and other environments that were not previously attributable to known microbes.

Additional Information

© 2001 American Association for the Advancement of Science. Received 28 February 2001; accepted 11 May 2001. We thank T. B. Stanton for a culture of T. bryantii and for purified genomic DNA of B. hyodysenteriae B-78 (ATCC 27164); E. P. Greenberg for cultures of S. halophila RS1 (ATCC 29478), T. denticola, and T. pectinovorum VPI D-36-DR-2 (ATCC 33768); S. Leschine for a culture of S. zuelzerae; and T. M. Schmidt for helpful discussions. Supported by NSF grants IBN97-09000 (J.A.B.), OCE98-17064 (N.E.O.), and BIR91-20006 (Center for Microbial Ecology at MSU).

Additional details

Created:
August 22, 2023
Modified:
October 23, 2023