SULFATE-CONTROLLED SYNCHRONY OF ASTASIA-LONGA

Sulfur-limited cultures of Astasia longa were grown in a chemostat at a series of generation times. The mean cell volumes decrease as generation time increases. The range of cell volume as measured by determinations of the log-normal volume distributions also shows a decrease with increasing generation time. Pulse additions of sulfate to cultures maintained at a 56-hour generation time led to a synchronous burst of cell division three hours after its addition. Ninety per cent of the cells divide in the next three hours. Protein, DNA, and RNA ger 106 cells were each analyzed during this period and showed changes consistent with previous work on temperature-synchronised Astasia. © 1969.