SEQUENTIAL REPLICATION OF THE BACILLUS SUBTILIS CHROMOSOME, III. REGULATION OF INITIATION

Publisher Website
Google Scholar
Abstract
In contrast to strain W23 of Bacillus subtilis, strain W168 does not show polarity of chromosome replication when the marker frequencies are compared in DNA from exponential phase cells and in DNA from stationary phase cells. This apparent nonpolar behavior of strain W168 arises from a less rigid regulation of chromosome replication rather than from a difference in the mode of replication (origin and direction of replication). When the spore DNA of W168 is used as the standard, exactly the same polarity as in strain W23 is observed. These results indicate that strain W168 does not accumulate completed chromosomes in the stationary phase, while in the spores chromosomes are in the completed form. In addition, evidence for multifork replication of chromosomes occuring in rapidly growing cells is presented.