Cell cycle analysis

Cell cycle analysis of Escherichia coli cells

C period = the time for a round of chromosome replication D period = the time between the end of a round of chromosome replication and cell division

1. Determination of initiation age (a_i) and C+D:

From flow cytometry analysis of cells treated with rifampicin and cephalexin (run-out histogram) the proportions of cells that had notinitiated replication at the time of drug action (4-origin-cells, streaked) and cells that initiated (8-origin-cells) can be estimated.The initiation age (ai) can be found from thetheoretical age distribution described by this formula,

• F = 2 - 2^((τ-ai)/τ)

where F is the fraction of cells that had not initiated and  is the generation time, or from the estimated graph of the theoretical age distribution (streaked portion).

The C+D period is estimated from the initiation age (ai), the generation time () and the number of generations spanned per cell cycle.