DNA cycle of Myxococcus xanthus

David Zusman*, Eugene Rosenberg

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


The rate of DNA synthesis during the division cycle of Myxococcus xanthus growing on a defined medium has been determined. Non-synchronized exponential phase cultures were pulse-labeled with radioactive thymidine and then prepared for quantitative autoradiography. Measurements of both cell size and grain number were performed on 2400 cells. Analysis of the distribution of grains in each of 20 size groups showed that: (a) cells do not synthesize any DNA during 20% of the division cycle; (b) those cells that are synthesizing DNA are doing so at a constant rate independent of cell size or cell age; and (c) the DNA cycle extends from 0.02 to 0.81 generation, septum formation occurs at 0.90 generation, and physical separation of sister cells at 1.0 generation. Chemical analysis of the average DNA content of M. xanthus growing in the defined medium yielded 14 × 10-9 μg DNA per cell, corresponding to 1.7 ± 0.2 chromosomes/cell. Thus, the rate of DNA synthesis reported here, 2.5 × 104 base pairs/minute, is the rate of synthesis of one replicating chromosome.

Original languageEnglish
Pages (from-to)609-619
Number of pages11
JournalJournal of Molecular Biology
Issue number3
StatePublished - 14 May 1970
Externally publishedYes


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