Related Experiment Video
Updated: Jun 29, 2026

C. elegans Tracking and Behavioral Measurement
Published on: November 17, 2012
Nitrogen fixation by symbiotic and free-living spirochetes
T G Lilburn1, K S Kim, N E Ostrom
1Ribosomal Database Project, Center for Microbial Ecology, Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824-1101, USA.
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.
Related Concept Videos
Free-falling Bodies: Introduction
Torsional Pendulum
As long as the rigid body's angular displacement is small, its oscillation can be modeled as a linear angular oscillation. The amplitude of the oscillation is an angle. The role of mass is played by the...
Self-Locking Screw
A square-threaded screw jack carrying a load is considered self-locking if the screw retains its position even after the moment applied to it is removed.
Rotational Motion about a Fixed Axis
Torsion of Noncircular Members
Buoyancy and Stability for Submerged and Floating Bodies

