Fine structure of fruiting bodies of Stigmatella aurantiaca (Myxobacterales).

The fruiting body of Stigmatella aurantiaca consists of a thick stalk supporting a number of individual cysts. The stalk is made of discontinuous tubules, of dimensions known for vegetative cells, which are oriented parallel to the longitudinal axis of the stalk. The red-brown cysts contain numerous, randomly oriented myxospores which are surrounded by thick, fibrous capsules. Their cell walls are wavy or ruffled and exhibit fewer budlike infoldings than reported for myxospores induced in liquid. We suggest that the extended time period available for metabolic and regulatory adjustments by the cell during morphogenesis within cysts accounts for the presence of considerably fewer deep cell wall infoldings than in glycerol-induced myxospores.