In all organisms, mild heat pretreatments induce tolerance to high temperatures. In the yeast Saccharomyces cerevisiae, such pretreatments strongly induce heat-shock protein (Hsp) 104, and hsp104 mutations greatly reduce high-temperature survival, indicating Hsp1O4 plays a critical role in induced thermotolerance. Surprisingly, however, a heat-shock transcription factor mutation (hsf1-m3) that ...

Chronic thermotolerance is an operational definition for that resistance to cell killing by heat which develops during a protracted exposure at temperatures generally in the range of 4I.5-42.5T which is usually observed as a reduction in the slope of the survival curve. While Chinese hamster ovary (CHO) cells are generally more sensitive to high-temper ature heat shock than HeLa cells, studies ...

We have discovered that three longevity mutants of the nematode Caenorhabditis elegans also exhibit increased intrinsic thermotolerance (Itt) as young adults. Mutation of the age-1 gene causes not only 65% longer life expectancy but also Itt. The Itt phenotype cosegregates with age-1. Long-lived spe-26 and daf-2 mutants also exhibit Itt. We investigated the relationship between increased thermo...

Induced thermotolerance in murine embryos occurs at the 8-cell stage when embryos are maintained in vitro but not until the blastocyst stage if development proceeds in vivo. Present results indicate that ability of embryos to undergo induced thermotolerance is not limited by heat shock protein 70 (HSP70) synthesis. Exposure of 8-cell embryos to 40 degrees C enhanced synthesis of 2 constitutive ...

Increased thermotolerance of Listeria monocytogenes induced by exposure to a high NaCl concentration or a sublethal heat shock was concurrent with increased thermal stability of the 30S ribosomal subunit as measured by differential scanning calorimetry. It is proposed that protection of the 30S subunit is a critical mechanism for increased thermotolerance.

ClpB is a highly conserved heat shock protein that is essential for thermotolerance in bacteria and eukaryotes. One distinctive feature of all bacterial clpB genes is the dual translation of a truncated 79-kDa form (ClpB-79) in addition to the full-length 93-kDa protein (ClpB-93). To investigate the currently unknown function of ClpB-79, we have examined the ability of the two different-sized C...

The functional relationship between thermotolerance and heat shock protein (HSP) expression is well described. However, the intraspecific variation in HSP70 expression and heat resistance is not fully understood. Some studies have shown a correlation between thermotolerance and HSP70 expression levels at the intraspecific level, whereas others have not, and results depend on species, developmen...

The kinetics of thermotolerance decay and cell proliferation was determined following initial heat treatments of 10 or 30 min at 44 degrees in Chinese hamster ovary cells. Thermotolerance was more pronounced following the longer initial heat treatment, but maximal tolerance developed by 10 hr in both cases. After its maximal development, tolerance decayed in an exponential manner. The half-time...

Heat acclimation improves the tolerance of organisms to severe heat stress. Our previous work showed that in Arabidopsis (Arabidopsis thaliana), the “memory” of heat acclimation treatment decayed faster in the absence of the heat-stress-associated 32kD protein HSA32, a heat-induced protein predominantly found in plants. The HSA32 null mutant attains normal short-term acquired thermotolerance bu...

Heat acclimation improves the tolerance of organisms to severe heat stress. Our previous work showed that in Arabidopsis (Arabidopsis thaliana), the "memory" of heat acclimation treatment decayed faster in the absence of the heat-stress-associated 32-kD protein HSA32, a heat-induced protein predominantly found in plants. The HSA32 null mutant attains normal short-term acquired thermotolerance b...