Repair of thermal damage to the Escherichia coli nucleoid

Abstract

The folded chromosome or nucleoid of Escherichia coli was analyzed by lowspeed sedimentation in neutral sucrose gradients after heat treatment (30 min at

Quantifying the heterogeneous heat response ofEscherichia coliunder dynamic temperatures

“…An important component affected by the temperature stress is the DNA molecule, e.g. the heat induces breaks in the DNA strain (Pellon et al 1980;Pellon and Gomez 1981). As a reaction, many micro-organisms produce heat shock proteins that are known to suppress the inactivation of several metabolic macromolecules (e.g.…”

The death and lysis of microorganisms in environmental processes

“…In E. coli, the effect of heat has been suggested to result in the denaturation of the cell wall leaving the peptidoglycan layer weakened at one or two points after which the plasma membrane ruptures [206]. Some association of proteins with the nucleoids also occurs as a result of mild heat treatment [207].…”

A note on the repair of the Escherichia coli nucleoid structure after heat shock

“…These observations suggest that after a sublethal heat treatment (i.e. heat shock) the complete repair of the nucleoid structure is attained in more than 90% of the nucleoids, and more than 90% of the cells are able to recuperate from this treatment and regain their viability on plates (Pellon & Gomez 1981). The results reported here also suggest that the nucleoid structural repair after heat shock is different from the repair after heat damage resulting in a sizeable loss in cell viability.…”

“…This is due to the use of hyperthermia in the clinical treatment of cancer (Storm 8z Morton 1982). In prokaryotes, it has been demonstrated that the Escherichia coli folded chromosome or nucleoid is a suitable model system to study heat damage and repair (Pellon et al 1980;Pellon & Gomez 1981;. Studies on heat damage and repair are also important in the food related industries where heat is the main agent employed to control micro-organisms.…”

“…The repair process was monitored by determining the sedimentation coefficients of the nucleoids in neutral sucrose gradients. Previous work has shown how the nucleoids are repaired after heat damage resulting in a sizeable loss in 002 1 -8847/83/06oo-O437 $02.00 @ 1983 The Society for Applied Bacteriology cell viability in the culture (Pellon & Gomez 1981 ;).…”