Table 1.

Phenotypic categories of heat-sensitive mutants

30–50 °C phenotype37–50 °C phenotypeDescription
Sensitive (P < 0.01)Sensitive (P < 0.01)Strains are hypersensitive to heat when shifted from 30–50 °C and do not acquire thermotolerance after pretreatment at 37 °C (10 genes; Table 2)
Sensitive (P < 0.01)Resistant (P value for sensitivity is > 0.01)Strains are hypersensitive to heat when shifted from 30–50 °C and do acquire thermotolerance after pretreatment at 37 °C (49 genes; Table 3)
Wild-type (P value for sensitivity is > 0.05)Sensitive (P < 0.05)Strains exhibit sensitivity to heat similar to wild type when shifted from 30–50 °C but exhibit hypersensitivity to lethal heat shock after pretreatment at 37 °C (nine genes; Table 4)