Relation between growth and replication in bacteria

The control of chromosome replication in bacteria depends on the cell growth; a round of replication is initiated when the cell mass (or protein) per replication origin has reached a certain critical level. Relative values of this “initiation mass” have previously been estimated from the evaluation of experiments involving age fractionation of radioactively labelled bacterial cultures. Here a theoretical analysis is presented which permits a simple and accurate method to determine this initiation mass from a few parameters easily observable with exponential cultures, without the need for age fractionation.