Sporulationsverhalten von Bacillus megaterium während Kohlenstoffhunger

Abstract

AbstractSome parameters of sporulation were determined from different carbohydrate‐limited B. megaterium cultures, which grew with doubling times of τ = 45, 80, and 190 min, respectively. The frequency of spore formation was 90–95%.Forespores and spores appeared asynchroneously. This asynchrony was due to the heterogenity in cell size of the populations. Spores within the smallest cells developed 90 min later than in the larger ones. As the extent of synchrony was the same with all three media, initiation of sporogenesis should occur independently of the respective stage of the cell cycle.The time passing between t0 (begin of the stationary growth phase) and the formation of the spore septum varied in the different media. Thus, the time at which the latter process starts is not directly determined by the end of the net growth but probably by processes which are connected with initiation of cell division.A model of cell division is presented according to that membrane synthesis during elongation of cells occurs at an annular zone at the newly formed poles of daughter cells. Sporulation septum then might be the product of a reinitiated, additional membrane synthesis at this site, the activity of which normally is repressed by the next division and remains repressed under non‐starvation conditions.