TY - JOUR
T1 - DNA cycle of Myxococcus xanthus
AU - Zusman, David
AU - Rosenberg, Eugene
N1 - Funding Information:
We are indebted to Dr F. Eiserling for criticism of the manuscript and to Dr P. Gottlieb for assistance in relating size groups to age groups. This investigation was supported by National Science Foundation grant GB-8708. One of us (D.Z.) is a recipient of a National Institutes of Health predoctoral traineeship (5-TOI-GM 01297-05).
PY - 1970/5/14
Y1 - 1970/5/14
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=0014944991&partnerID=8YFLogxK
U2 - 10.1016/0022-2836(70)90285-8
DO - 10.1016/0022-2836(70)90285-8
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AN - SCOPUS:0014944991
SN - 0022-2836
VL - 49
SP - 609
EP - 619
JO - Journal of Molecular Biology
JF - Journal of Molecular Biology
IS - 3
ER -