Patterns of intraspecific variability in the response to caloric restriction
Caloric restriction (CR) is cited as the most robust means of increasing lifespan across a range of taxa, yet there is a high degree of variability in the response to CR, both within and between species. To examine the intraspecific evolutionary conservation of lifespan extension by CR, we tested the effects of chronic caloric restriction (CCR) at multiple food levels and of intermittent fasting (IF) in twelve isolates from the Brachionus plicatilis species complex of monogonont rotifers. While CCR generally increased or did not change lifespan and total fecundity, IF caused increased, unchanged, or decreased lifespan, depending upon the isolate, and decreased total fecundity in all but one isolate. Lifespan under ad libitum (AL) feeding varied among isolates and predicted the lifespan response to CR: longer-lived isolates under AL were less likely to have a significant increase in lifespan under CCR and were more likely to have a significantly shortened lifespan under IF. Lifespan under AL conditions and the response to CR were not correlated with hydroperiodicity of native habitat or with time in culture. Lack of trade-off between lifespan and fecundity under CCR, and differences in lifespan and fecundity under CCR and IF, even when average food intake was similar, suggest that longevity changes are not always directly determined by energy intake and that CCR and IF regimens extend lifespan through diverse genetic mechanisms.
Available from: Terry W Snell
- "The response to CR varied with reproductive mode and degree or type of CR, with differences in lifespan, fecundity, and the trade-off between the two (Gribble & Mark Welch 2013). More recently, we extended earlier work demonstrating a maternal effect of CR on lifespan of offspring (Kaneko et al. 2011) by documenting that maternal CR can partially rescue the deleterious effects of maternal age on the lifespan of offspring (Gribble et al. 2014). To understand the intraspecific evolutionary conservation of lifespan extension by CR, we tested the effects of CCR and IF in 12 isolates from a group of closely related species including B. manjavacas (Gribble et al. forthcoming). "
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ABSTRACT: Comparative biogerontology has much to contribute to the study of aging. A broad range of aging rates has evolved to meet environmental challenges, and understanding these adaptations can produce valuable insights into aging. The supra Phylum Lophotrochozoa is particularly understudied and has several groups that have intriguing patterns of aging. Members of the lophotrochozoan phylum Rotifera are particularly useful for aging studies because cohort life tables can be conducted with them easily, and biochemical and genomic tools are available for examining aging mechanisms. This paper reviews a variety of caloric restriction regimens, small molecule inhibitors, and dietary supplements that extend rotifer lifespan, as well as important interactions between caloric restriction and genotype, antioxidant supplements, and TOR and JNK pathways, and the use of RNAi to identify key genes involved in modulating the aging response. Examples of how rapamycin and JNK inhibitor exposure keeps mortality rates low during the reproductive phase of the life cycle are presented, and the ease of conducting life table experiments to screen natural products from red algae for life extending effects is illustrated. Finally, experimental evolution to produce longer-lived rotifer individuals is demonstrated, and future directions to determine the genetic basis of aging are discussed.
Available from: Kristin E Gribble
- "Epigenetic rescue of maternal aging effects , K . E . Gribble et al . 627 ª 2014 The Authors . Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd . due to CR or other interventions in additional species will be complicated by the genomic diversity caused by sexual reproduction . While evolutionary arguments may be made to support adaptive epigenetic effects of food restriction in humans , no co"
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ABSTRACT: While many studies have focused on the detrimental effects of advanced maternal age and harmful prenatal environments on progeny, little is known about the role of beneficial non-Mendelian maternal inheritance on aging. Here, we report the effects of maternal age and maternal caloric restriction (CR) on the life span and health span of offspring for a clonal culture of the monogonont rotifer Brachionus manjavacas. Mothers on regimens of chronic CR (CCR) or intermittent fasting (IF) had increased life span compared with mothers fed ad libitum (AL). With increasing maternal age, life span and fecundity of female offspring of AL-fed mothers decreased significantly and life span of male offspring was unchanged, whereas body size of both male and female offspring increased. Maternal CR partially rescued these effects, increasing the mean life span of AL-fed female offspring but not male offspring and increasing the fecundity of AL-fed female offspring compared with offspring of mothers of the same age. Both maternal CR regimens decreased male offspring body size, but only maternal IF decreased body size of female offspring, whereas maternal CCR caused a slight increase. Understanding the genetic and biochemical basis of these different maternal effects on aging may guide effective interventions to improve health span and life span.
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