Timing mechanism and effective activation energy concerned with aging and lifespan in the long-lived and thermosensory mutants of Caenorhabditis elegans

The lifespans of many poikilothermic animals, including the nematode Caenorhabditis elegans, depend significantly on environmental temperature. Using long-living, thermosensory mutants of C elegans, we tested whether the temperature dependency of the mean lifespan is compatible with the Arrhenius equation, which typically represents one of the chemical reaction rate theories. The temperature dependency of C elegans was the Arrhenius type or normal, but daf-2(e1370) mutants were quite different from the others. However, taking into account the effect of the thermal denaturation of DAF-2 with the temperature, we showed that our analyzed results are compatible with previous ones. We investigated the timing mechanism of one parameter (the onset of biodemographic aging (t(o))) in the lifespan equation by applying the RNAi feeding method to daf-2 mutants in order to suppress daf-16 activity at different times during the life cycle. In summary, we further deepened the biological role of two elements, t(o) and z (the inverse of the aging rate), in the lifespan equation and mean lifespan formulated by our diffusion model z(2) = 4Dt(o), where z is composed of t(o) and D (the diffusion constant). (C) 2012 Elsevier Ireland Ltd. All rights reserved.