Slow growing Bacillus subtilis: deoxyribonucleic acid replication in turbidostat cultures

Comparisons of slowly growing Bacillus subtilis cultures grown in batch culture, a chemostat, and a turbidostat were made. Cultures in a turbidostat were found to grow optimally and to be in balanced growth. The duration of deoxyribonucleic acid (DNA) replication, or C period, was estimated by means of an autoradiographic analysis, a genetic analysis, and determinations of DNA per cell. These measurements were performed on cells growing at different slow rates. The results showed that the C period increased with increasing generation times, but the increase in duration of the C period was not proportional to the increase in generation time.