DUPLICATION OF BACTERIAL CELL AND ITS INITIATION

The model of Cooper & Helmstetter (1968) describes the relationship between DNA replication and the division cycle of bacteria at balanced growth. In order to render this model applicable to unbalanced growth we suggest a specific mechanism initiating the DNA replication and acting as an oscillatory pacemaker for several fundamental processes within the bacterial cell. From the improved model, the quantities of cell components (genetic markers, DNA, 'nascent' replication points, number of nuclei and number of cells) as well as the lag times, after which these components respond to a shift-up, are calculated. Experimental data quoted in the literature are in good agreement with the predictions based on the model. Theoretical and experimental results indicate that Maaløe & Kjeldgaard's (1966) theorem of constant macromolecular chain growth rate does not hold for the formation of both nascent replication points and ribosomes. © 1969 Academic Press Inc. (London) Ltd. All rights reserved.