title: Heat damage and repair in the Escherichia coli nucleoid: kinetics based on sedimentation analysis.
abstract: Changes in the structure of the Escherichia coli nucleoid during heat damage and repair were followed by sedimentation analysis in neutral sucrose gradients. Heating at 50 degrees C results first in a decrease in the sedimentation coefficient of the isolated nucleoid. Increasing the heating time, a subsequent increase in sedimentation coefficient is observed. After a heat shock (i.e. 4 min at 50 degrees C), a short incubation at 25 degrees C (i.e. 5 min) allows the nucleoid to repair and return to the sedimentation coefficient of control unheated nucleoids. The nucleoids heated at 50 degrees C for longer periods and incubated afterwards at 25 degrees C demonstrate a different pattern of structural repair. They associate with protein in the first stage of the repair period.
mesh_terms: D001426:Bacterial Proteins / Q000502:physiology; D002499:Centrifugation, Density Gradient; D002876:Chromosomes, Bacterial / Q000502:physiology; D004260:DNA Repair; D004269:DNA, Bacterial / Q000502:physiology; D004278:DNA, Superhelical / Q000502:physiology; D004926:Escherichia coli / Q000502:physiology / Q000648:ultrastructure*; D006358:Hot Temperature; D007700:Kinetics; D009940:Organoids / Q000502:physiology
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004278:DNA, Superhelical