Thiothrix

Thiothrix is a genus of filamentous sulfur-oxidizing bacteria, related to the genera Beggiatoa and Thioploca. Usually Gram negative but can be Gram variable rods (0.7-1.5x1.2-2.5 µm) forming ensheathed multicellular filaments attached at base and forming gonidia at the free end. The apical gonidia have gliding motility. Rosettes of the filaments are not always formed but are typical. Sulfur is deposited in invaginations within the cell membrane.