Thermotolerance induced by 2,4-dinitrophenol.

The capacity of 2,4-dinitrophenol (DNP) to induce thermotolerance in 3-day-old larvae of Lymnaea has been investigated. Induction of thermotolerance is dependent on the DNP concentration, the duration of treatment, and on the pH of the medium. Optimal conditions for the induction of thermotolerance are 10 min, 2.5 mM DNP at pH 4.7. Thermotolerance has been expressed in percentages of survival. Thermotolerance is maximal at 15 min after DNP treatment and decreases subsequently. DNP suppresses protein synthesis. Recovery starts 20 min after treatment, when thermotolerance is decreasing already. DNP does not induce the synthesis of the typical heat shock proteins (HSPs). It is concluded that DNP induces a state of thermotolerance of short duration, which is not accompanied by HSP synthesis.