Open AccessGrowth Phase-Coupled Alterations in Cell Structure and Function of Escherichia coli
Author(s) -
Hideki Makinoshima,
ShinIchi Aizawa,
Hideo Hayashi,
Takeyoshi Miki,
Akiko Nishimura,
Akira Ishihama
Publication year - 2003
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.185.4.1338-1345.2003
Subject(s) - rpos , biology , sigma factor , escherichia coli , flagellum , mutant , stationary phase , transcription (linguistics) , rna polymerase , cell division , gene , microbiology and biotechnology , cell , gene expression , biochemistry , chemistry , promoter , chromatography , linguistics , philosophy
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.