Growth phase-coupled alterations in cell structure and function of Escherichia coli.
Escherichia coli cultures can be fractionated into more than 20 cell populations, each having a different bouyant density and apparently representing a specific stage of cell differentiation from exponential growth to stationary phase (H. Makinoshima, A. Nishimura, and A. Ishihama, Mol. Microbiol. 43:269-279, 2002). The density increase was found to be impaired at an early step for a mutant E. coli with the disrupted rpoS gene, which encodes the RNA polymerase RpoS (sigma-S) for stationary-phase gene transcription. This finding suggests that RpoS is need for the entire process of cell density increase. In the absence of RpoF sigma factor, the flagella are not formed as observed by electron microscopy, but the growth phase-coupled density increase takes place as in wild-type E. coli, confirming that the alteration in cell density is not directly correlated with the presence or absence of flagella. In the stationary-phase cells, accumulation of electron-dense areas was observed by electron microscopic observation of bacterial thin sections. By chemical determination, the increase in glycogen (or polysaccharides) was suggested to be one component, which contributes to the increase in weight-to-volume ratio of stationary-phase E. coli cells.
Makinoshima
Hideki
H
Division of Molecular Biology, Nippon Institute for Biological Science, Ome, Tokyo 198-0024, Japan.
Aizawa
Shin-Ichi
S
Hayashi
Hideo
H
Miki
Takeyoshi
T
Nishimura
Akiko
A
Ishihama
Akira
A
D001426:Bacterial Proteins / Q000235:genetics*; D002499:Centrifugation, Density Gradient; D003470:Culture Media; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development* / Q000648:ultrastructure*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D008854:Microscopy, Electron; D012808:Sigma Factor / Q000235:genetics*
D001426:Bacterial Proteins; D003470:Culture Media; D029968:Escherichia coli Proteins; D012808:Sigma Factor; C069567:sigma factor KatF protein, Bacteria