Heating stress patterns in Caenorhabditis elegans longevity and survivorship
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Survival data from Caenorhabditis elegans strain TJ1060 (spe-9; fer-15) following brief exposure to 35 °C have been investigated. Three experiments with 3-day-old worms were conducted with heat duration ranging between 0 and 12 hours. A statistically significant increase in life expectancy was observed in the groups heated for less than 2 hours, as compared to the unheated control groups. In different experiments P-values for the observed life spans under the hypothesis that heating has no influence on longevity were P < 0.004 after 0.5 hour heat, P < 0.012 after 1 hour heat and P < 0.055 after 2 hours of heating. A biphasic survival model with Gamma distributed frailty has been constructed to describe the survival of worms after heating. The increase in the remaining life expectancy is determined by more effective protection by heat-induced substances in the ages yanger than 27 days. The unheated control group demonstrated acquired heterogeneity of frailty with chronological age while the heat-induced substances defend the worms in a universal way and protect against the development of frailty.
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- Cox DR and Oakes D (1984) Analysis of Survival Data. Chapman & Hall, New YorkGoogle Scholar
- Dahlgaard J, Loeschke V, Michalak P and Justesen J (1998) Induced thermotolerance and associated expression of the heat-shock protein Hsp70 in adult Drosophila melanogaster. Func Ecol 12: 786-793Google Scholar
- Gompertz B (1825) On the nature of the function expressive of the law of human mortality, and on a new mode of determining the value of life contingencies. Phil Trans Phil Soc London A 115: 513-585Google Scholar
- Johnson TE and Hartman PS (1988) Radiation effects on life span in Caenorhabditis elegans. J Gerontol A Biol Sci Med Sci 43: B137-B141Google Scholar
- Johnson TE, Lithgow GJ and Murakami S (1996) Hypothesis: Interventions that increase the response to stress offer the potential for effective life prolongation and increased health. J Gerontol A Biol Sci Med Sci 51A: B392-B395Google Scholar
- Kalbfleisch JD and Prentice RL (1980) The Statistical Analysis of Failure Time Data. Wiley, New YorkGoogle Scholar
- Sohal RS and Allen RG (1984) Relationship between metabolic rate, free radicals, differentiation, and aging: A unified theory. In: Woodland AD, Blackett AD and Hollaender A (eds) Molecular Biology of Aging, pp 75-104. Plenum Press, New YorkGoogle Scholar
- Tatar M (1999) Transgens in the analysis of life span and fitness. Am Nat 154: S67-S81Google Scholar
- Vanfleteren JR, De Vreese A and Braeckman BP (1998) Twoparameter logistic and Weibull equations provide better fits to survival data from isogenic populations of Caenorhabditis elegansin axenic culture than does the Gompertz model. J Gerontol A Biol Sci Med Sci 53A: B393-B403Google Scholar
- Vaupel JW, Johnson TE and Lithgow GJ (1994) Rates of mortality in population of Caenorhabditis elegans(technical comments). Science 266: 826-828Google Scholar
- Walker GA, Walker DW and Lithgow GJ (1998) A relationship between thermotolerance and longevity in Caenorhabditis elegans. J Invest Dermatol Symp Proc 3: 6-10Google Scholar