Figure 2.

The proposed model is compatible with diverse growth conditions. (A) Definition of classical Cooper-Helmstetter C and D periods (Helmstetter et al., 1968). (B) Natures of, and relationships among, slow and fast growth in terms of (C+D) sequences and the effect of coordination control in the two situations. Progression permission is indicated by a filled upward arrow; downward arrows indicate the corresponding permitted cell division and replication initiation. (C) (C+D) sequences for an E. coli K12 strain with non-canonical period lengths [Td = 55 min; (C+D) = 100 min, with a 55 min C period and a 45 minute D period; Nielsen et al., 2007]. (D) Synchronous cell analysis of chromosome and divisome events under several slow growth conditions show that replication (purple) always begins soon after division (from Bates and Kleckner, 2005). (E) Relationships between the length of (C+D) and doubling time (Td) as a function of doubling time (from Helmstetter et al., 1968).