Biosynthetic requirements for the repair of sublethal membrane damage in Escherichia coli cells after pulsed electric fields
Article first published online: 3 FEB 2006
Journal of Applied Microbiology
Volume 100, Issue 3, pages 428–435, March 2006
How to Cite
García, D., Mañas, P., Gómez, N., Raso, J. and Pagán, R. (2006), Biosynthetic requirements for the repair of sublethal membrane damage in Escherichia coli cells after pulsed electric fields. Journal of Applied Microbiology, 100: 428–435. doi: 10.1111/j.1365-2672.2005.02795.x
- Issue published online: 3 FEB 2006
- Article first published online: 3 FEB 2006
- 2005/0597: received 27 May 2005, revised 27 September 2005 and accepted 28 September 2005
- Escherichia coli;
- membrane damage;
- pulsed electric fields;
- sublethal injury
Aims: The aim was to evaluate the biosynthetic requirements for the repair of sublethal membrane damages in Escherichia coli cells after exposure to pulsed electric fields (PEF).
Methods and Results: The partial loss of the barrier and homeostatic functions of the cytoplasmic membrane was examined by adding sodium chloride to the recovery media. More than 4 log10 cycles of survivors were sublethally injured after PEF. Repair of such sublethal membrane damages occurred when survivors to PEF were incubated in peptone water for 2 h. Two different types of sublethally injured cells were detected. Whereas a small proportion (<5%) repaired after PEF in less than 2 min, the repair of the remaining 95% injured cells lasted 2 h and was dependent on biosynthetic requirements. The addition of inhibitors such as chloramphenicol, cerulenin, penicillin G, rifampicin and sodium azide to the liquid repair medium showed that the repair required energy and lipid synthesis, and was not dependent on protein, peptidoglican or RNA synthesis.
Conclusions: Cell survival after PEF is dependent on the repair of the cytoplasmic membrane. Requirement of lipid synthesis for the repair of sublethally injured cells confirms that the cytoplasmic membrane is a target directly involved in the mechanism of inactivation by PEF.
Significance and Impact of the study: Knowledge about the damages inflicted by PEF might help in the design of more efficient treatments.