Transition phenomena in bacterial growth between logarithmic and stationary phases.

A method to calculate the age distribution of the cells in the transition phase starting from that of the cells in logarithmic phase is described. It is clarified that two transition phenomena (decrease in the growth rate of cell number and partial synchronization) in the transition phase come, mathematically, from the fact that dag/dt > 0 (ag = generation time). The cell age at which septum becomes observable is estimated from the age distribution of the cells and the ratio of septated cells at each time in the transition phase. The result suggests that the cell age at which septum synthesis starts increases in the transition phase and that the mode of septum synthesis changes during that phase.