Cell division and trichome breakage inBeggiatoa.

The process ofBeggiatoa trichome division was elucidated through phase-contrast microscopy and transmission and scanning electron microscopy. Trichome breakage and dispersion is accomplished by the formation of sacrificial cells (necridia) at various points within the trichome. Upon dying, the sacrificial cells lyse, dividing the trichome into two daughter trichomes. This process is identical with that found in many oscillatorian blue-green bacteria, but differs from the mechanism of trichome division in most of the other flexuous gliding bacteria. Cellular division within the trichome occurs by septation, involving the cytoplasmic membrane and the electron-dense L2 (peptidoglycan) layer. The outer envelope layers do not take part in division.