title: Noise-driven onset time of biodemographic aging.
abstract: The lifespan of each individual, even in an isogenic cohort and a uniform environment, is quite different. The genetic factors influencing the lifespan in humans as well as animal models are few. The balance is attributed to "chance" variations. In this study, we focus on a third factor, noise or chance variations, as well as on genetic and environmental factors and examine how biodemographic aging is related to stochastic fluctuations, or noise. To elucidate the third factor in relation to aging and lifespan, we employed the nematode Caenorhabditis elegans, which can provide an ideal system for analyzing the mathematical and biophysical models. An amplification of ATP noise was clearly evident from around the onset of biodemographic aging (t(0)) as if the t(0) was synchronized with or derived from the amplification of noise. Furthermore, the expression noise of the unc-54 gene, which encodes the myosin heavy chain, increased from around the t(0). In contrast, the noise of genes related to the mitochondrial respiratory chain was almost constant with aging. There is a high energy barrier between life and death. Here we propose that the transition from living to dying may be facilitated by noise amplification. The finite value (or non-zero) of t(0) is essential to the lifespan equation derived from the diffusion model.
authors.affiliation: Life Sciences, Course of Biosciences, University of Tokai, 317 Nishino, Numazu, Shizuoka 410-0395 Japan. sudsai@wing.ncc.u-tokai.ac.jp
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Suda
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis / Q000378:metabolism; D000375:Aging / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D005786:Gene Expression Regulation / Q000502:physiology; D008136:Longevity / Q000235:genetics*; D023421:Models, Animal; D018995:Myosin Heavy Chains / Q000096:biosynthesis / Q000235:genetics; D013269:Stochastic Processes
chemical_list: D000255:Adenosine Triphosphate; D018995:Myosin Heavy Chains
keywords: ATP noise; C. elegans; Chance variations; Gene expression noise; Noise amplification; Onset of biodemographic aging; Stochastic fluctuations; Timing mechanism