Intensive DNA Replication and Metabolism during the Lag Phase in Cyanobacteria

Unlike bacteria such as Escherichia coli and Bacillus subtilis, several species of freshwater cyanobacteria are known to contain multiple chromosomal copies per cell, at all stages of their cell cycle. We have characterized the replication of multi-copy chromosomes in the cyanobacterium Synechococcu...

Full description

Saved in:
Bibliographic Details
Published in:PloS one 2015-09, Vol.10 (9), p.e0136800-e0136800
Main Authors: Watanabe, Satoru, Ohbayashi, Ryudo, Kanesaki, Yu, Saito, Natsumi, Chibazakura, Taku, Soga, Tomoyoshi, Yoshikawa, Hirofumi
Format: Article
Language:English
Subjects:
Accumulation
Amino acids
Analysis
Bacteria
Batch culture
Cell culture
Cell cycle
Cell division
Cell growth
Cell metabolism
Chlamydomonas reinhardtii
Chloroplasts
Chromosomes
Chromosomes, Bacterial - genetics
Copy number
Cyanobacteria
Deoxyribonucleic acid
DNA
DNA biosynthesis
DNA Replication
DNA topoisomerase
DNA, Bacterial - genetics
E coli
Elongation
Escherichia coli
Flow cytometry
Gene expression
Genetic aspects
Lag phase
Light
Linear phase
Mathematics
Metabolism
Metabolites
Metabolome
Nalidixic acid
Phases
Physiological aspects
Physiology
Replication
RNA polymerase
Studies
Synechococcus
Synechococcus - cytology
Synechococcus - genetics
Synechococcus - growth & development
Synechococcus - metabolism
Synechococcus elongatus
Synechocystis
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Unlike bacteria such as Escherichia coli and Bacillus subtilis, several species of freshwater cyanobacteria are known to contain multiple chromosomal copies per cell, at all stages of their cell cycle. We have characterized the replication of multi-copy chromosomes in the cyanobacterium Synechococcus elongatus PCC 7942 (hereafter Synechococcus 7942). In Synechococcus 7942, the replication of multi-copy chromosome is asynchronous, not only among cells but also among multi-copy chromosomes. This suggests that DNA replication is not tightly coupled to cell division in Synechococcus 7942. To address this hypothesis, we analysed the relationship between DNA replication and cell doubling at various growth phases of Synechococcus 7942 cell culture. Three distinct growth phases were characterised in Synechococcus 7942 batch culture: lag phase, exponential phase, and arithmetic (linear) phase. The chromosomal copy number was significantly higher during the lag phase than during the exponential and linear phases. Likewise, DNA replication activity was higher in the lag phase cells than in the exponential and linear phase cells, and the lag phase cells were more sensitive to nalidixic acid, a DNA gyrase inhibitor, than cells in other growth phases. To elucidate physiological differences in Synechococcus 7942 during the lag phase, we analysed the metabolome at each growth phase. In addition, we assessed the accumulation of central carbon metabolites, amino acids, and DNA precursors at each phase. The results of these analyses suggest that Synechococcus 7942 cells prepare for cell division during the lag phase by initiating intensive chromosomal DNA replication and accumulating metabolites necessary for the subsequent cell division and elongation steps that occur during the exponential growth and linear phases.
ISSN:1932-6203
1932-6203
DOI:10.1371/journal.pone.0136800