Electron microscopy of negatively s

Electron microscopy of negatively stained cells from 1 to 2‐day‐old cultures revealed the presence of a single polar flagellum (Fig. 1B). Analysis of ultrathin cell sections showed a typical Gram‐negative structure of the cell wall and the presence of intracytoplasmic membranes (ICM), arranged as stacks of vesicular disks (Fig. 1C‐E). This ICM arrangement is characteristic of type I methanotrophs.