Axenic growth up-regulates mass-specific metabolic rate, stress resistance, and extends life span in Caenorhabditis elegans. - Houthoofd,K.; Braeckman,B.P.; Lenaerts,I.; Brys,K.; Vreese,A De.; Eygen,S Van.; Vanfleteren,J.R. (Exp Gerontol, 2002)