Fig. 2

Electron micrographs of N. briensis. A) TEM prepared by negative staining as previously described [14, 15]. Scale is 1000 nm. B) SEM of Nitrosospira briensis C-128. Glass coverslips were placed in a growing culture for approximately one month, removed and then fixed with 2 % glutaraldehyde in 0.1 % HEPES buffer overnight. The samples were subjected to alcohol series dehydration (50-100 % ethanol) and then chemically dried using hexamethyldisilazane. The image shows presumptive invaginations of the membranes of the cell. Scale is 500 nm