Extending life-span in C. elegans.

The life-span of the nematode Caenorhabditis elegans can be extended by at least six different mechanisms, including calorie restriction, reduced Ins/IGF-1 signaling, germline ablation, food sensing amphid ablation, mitochondrial deficiency, and decreased temperature. Reduced Ins/IGF-1 signaling and calorie restriction can also increase the life-span of flies and mice. The Brevia "Healthy animals with extreme longevity" by N. Arantes-Oliveira et al. (24 Oct. 2003, p. 611) showed that daf-2 RNAi treatment and gonad ablation of worms carrying the daf-2(e1368) hypomorphic mutation in the gene encoding the C. elegans Ins/IGF-1 receptor increases their life-span 6.0-fold. We have found that the average life-span of daf-2(e1370) mutants grown in axenic medium [a sterile liquid medium based on yeast extract, soy peptone, and hemoglobin; see (1)] was 90.9 days, representing a 6.3-fold life extension and a 7.5-fold adult life-span extension relative to wild-type controls grown on plate cultures seeded with live E. coli cells (1).