Table 3.

Wet heat resistance of spores of various strainsa

Expt no.bHeat shock gene mutatedWild-type background, D90-minc (strain)αβ background, D85-minc (strain)
1None 14 (PS832)9 (PS356)
1 dnaK 14 (PS3044)8 (PS3045)
2 None 14 (PS832) 12 (PS356)
2 hrcA (polar) 14 (PS3046) 10 (PS3047)
3 None 13 (PS832) 13 (PS356)
3 hrcA (nonpolar) 12 (PS3302) 15 (PS3303)
4 None 8 (PS832) 6 (PS356)
4 lon 7 (PS2542) 6 (PS2543)
5None 7 (PS832) 14 (PS356)
5 sigB 5 (PS2538) 4 (PS2539)
6 None 12 (PS832)15 (PS356)
6 ctsR 11 (PS3085)13 (PS3086)
  • a Spores were prepared and cleaned and wet heat resistance was measured as described in the text.

  • b Spores used in individual experiments were from separate preparations, but within an experiment, spores from different strains were prepared and tested together.

  • c Time in minutes to kill 90% of spores at either 90 or 85°C.