Autoradiographic studies of chromosome replication during the cell cycle of Streptococcus faecium

Journal Article · Sat Nov 01 00:00:00 EST 1986 · J. Bacteriol.; (United States)

OSTI ID:7119222

Higgins, M L; Koch, A L; Dicker, D T; Daneo-Moore, L

Analysis of the distribution of autoradiographic grains around cells of Streptococcus faecium which had been either continuously or pulse-labeled with tritiated thymidine (mass doubling time, 90 min) showed a non-Poisson distribution even when the distribution of cell sizes in the populations studied was taken into account. These non-Poisson distributions of grains were assumed to reflect the discontinuous nature of chromosome replication. To study this discontinuous process further, an equation was fitted to the grain distribution observed for the pulse-labeled cells that assumed that in any population of cells there were subpopulations in which there were zero, one, or two replicating chromosomes. This analysis predicted an average time for chromosome replication and for the period between completion of rounds of chromosome replication and division of 55 and 43 min, respectively, which were in excellent agreement with estimates made by other techniques. The present investigation extended past studies in indicating that the initiation and completion of rounds of chromosome replication are poorly phased with increases in cell volume and that the amount of chromosome replication may be different in different cell halves.

• Research Organization: Temple Univ. School of Medicine, Philadelphia
• OSTI ID: 7119222
• Journal Information: J. Bacteriol.; (United States), Vol. 168:2
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CHROMOSOMES
AUTORADIOGRAPHY
STREPTOCOCCUS
CELL CYCLE
DNA REPLICATION
THYMIDINE
TRITIUM COMPOUNDS
VARIATIONS
AZINES
BACTERIA
HETEROCYCLIC COMPOUNDS
LABELLED COMPOUNDS
MICROORGANISMS
NUCLEIC ACID REPLICATION
NUCLEOSIDES
NUCLEOTIDES
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
PYRIMIDINES
RIBOSIDES
550401* - Genetics- Tracer Techniques