Figure 1.

Thiovulum majus is a sulfur-oxidizing bacteria. (a) Individual cells attach to surfaces by exuding a mucous stalk. The stalk is invisible at magnification. Its position is shown with a dashed line. (b) Many of the flagella (thin white lines) surrounding a T. majus can be imaged with a scanning electron microscope. Note that this cell shrank during the ethanol dehydration. (c) Staining T. majus with DAPI (violet) and Dil (red) allows one to visualize the distribution of DNA and the cell membrane, respectively. (d) Sulfur globules within the cell posterior appear as bright micrometre-scale inclusions. The cell outline is shown in black. (e) A band of T. majus cells observed under a microscope. Note that the cells are organized into a dense front of cells. (f) The veil appears in an enrichment culture as a contorted white membrane extending the diameter of the serum bottle.