Thermally-induced cell lysis in Escherichia coli K12.
Escherichia coli cells exposed to high temperatures exhibit a progressive loss of viability. We observed two mechanisms of cell death induced by lethal temperatures: with and without lysis. The number of cells lysed by heat decreased at later stages of the growth curve, when cells were pre-treated at lower temperatures for 10 minutes and when cells were pre-treated with novobiocin, nalidixic acid and cadmium chloride. Cell lysis was similar in wild type, rpoH, groE and dnaK mutant cells as well as in cells which overproduce heat shock proteins GroE or DnaK. Results using cells aligned for cell division and cells growing at 42 degrees C, 45 degrees C and 47 degrees C suggest that cells near division are more sensitive to lysis and that a high concentration of heat-shock proteins increases their resistance to lysis.
Membrillo-Hernández
J
J
Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, D.F., México.
Núñez-de la Mora
A
A
del Rio-Albrechtsen
T
T
Camacho-Carranza
R
R
Gomez-Eichelmann
M C
MC
D002104:Cadmium / Q000494:pharmacology; D019256:Cadmium Chloride; D002455:Cell Division / Q000187:drug effects; D018835:Chaperonin 10 / Q000096:biosynthesis / Q000235:genetics; D018834:Chaperonin 60 / Q000096:biosynthesis / Q000235:genetics; D002712:Chlorides / Q000494:pharmacology; D004926:Escherichia coli / Q000166:cytology* / Q000187:drug effects / Q000235:genetics; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D018840:HSP70 Heat-Shock Proteins / Q000096:biosynthesis / Q000235:genetics; D006358:Hot Temperature; D009154:Mutation; D009268:Nalidixic Acid / Q000494:pharmacology; D009675:Novobiocin / Q000494:pharmacology
D018835:Chaperonin 10; D018834:Chaperonin 60; D002712:Chlorides; D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; D002104:Cadmium; D009675:Novobiocin; D009268:Nalidixic Acid; C063842:dnaK protein, E coli; D019256:Cadmium Chloride