Electron cryotomography reveals novel structures of a recently cultured termite gut spirochete

Electron cryotromography, a relatively new methodology in the field of microbiology, has been exploited by Murphy et al. (in this issue of Molecular Microbiology) in their analysis of the recently isolated termite gut spirochete Treponema primitia. Unique structures (bowls, arcades of hooks, cones at the cell ends, two layers of wall material) were evident from the analysis of its surface and internal constituents. These results, coupled to video microscopy analysis of swimming cells, allowed the authors to propose a model of cell motility. This highly significant paper highlights the importance of electron cryotomography to the field of microbiology. It also illustrates that newly cultured recalcitrant bacteria from complex environments are likely to possess novel structures not previously seen in other species.