The dynamism of Escherichia coli under high hydrostatic pressure ― repression of the FtsZ-ring formation and chromosomal DNA condensation

摘要

The elongation of Escherichia coli cells, in response to high hydrostatic pressure growth, is a unique property of this bacterium. Our high pressure observation microscope system (HPOMS) has provided direct observation of living E. coli elongated cells under high pressure. To study elongation mechanisms of E. coli under high pressure, the formation of FtsZ ring which was an early event of cell division was examined by immuno-fluorescence microscopy (IFM), and the chromosomal DNA was also detected by DAPI staining. The FtsZ-ring formation and the condensed nucleoid structure was observed in the filamentous cells when the cells were fixed after releasing the pressure. Surprisingly, no FtsZ ring was observed in whole filamentous cells, when the cells were fixed without decompression. Also the chromosomal DNA was segregated but not condensed at the same condition. These results suggested that the cell division of E. coli was inhibited by high hydrostatic pressure at early stage in the cell cycle before the FtsZ-ring formation during cultivation, however, cells could grow continuously without septum formation, chromosomal DNA condensation.