Sorangium cellulosum

Sorangium cellulosum is a soil-dwelling Gram-negative bacterium of the group myxobacteria. It is motile and shows gliding motility. Under stressful conditions this motility, as in other myxobacteria, the cells congregate to form fruiting bodies and differentiate into myxospores. These congregating cells make isolation of pure culture and colony counts on agar medium difficult as the bacterium spread and colonies merge. It has an unusually-large genome of 13,033,779 base pairs, making it the largest bacterial genome sequenced to date by roughly 4 Mb.