In addition, worms fed E. coli mutant strains with defects in ATP synthase (1100bc or AN120)

lived longer than worms fed OP50 [18]. This implied that the respiratory status of the bacteria was a crucial factor in the life span of the worms fed these diets. The NCT-501 relationship between respiration in the Trichostatin A nmr E. coli diet and the survival of the worms fed these diets identifies Q and ATP synthase as potential virulence factors. A virulence factor is any process, structure or metabolite required by a microorganism to be pathogenic to its host [19]. In this study we show that loss of respiration in E. coli yields delayed gut colonization and improved worm survival. Indeed, in young animals, few respiratory deficient E. coli are detected on the posterior side of the pharynx. Worms fed a mixture of Q-replete and Q-deficient E. coli show intermediate life span extension, indicating that the degree of bacterial colonization of the gut may be dose dependent. PF01367338 We hypothesize that decreased or delayed gut colonization confers a survival advantage to animals fed the

Q-deficient E. coli by diminishing or delaying stress due to high numbers of coliform bacteria. C. elegans fed respiratory-deficient E. coli diets serves as a model for characterizing the effects of anti-aging probiotic therapies. Results The GD1-mediated life span extension is independent of dietary restriction or worm Q content Findings from previous studies have suggested that the life span increase in C. elegans fed a Q-less (GD1) E. coli diet operates independently of dietary restriction [18]. Neither brood size nor worm size, two indicators of dietary restriction, aminophylline were altered in wild-type animals fed GD1 as compared to the standard OP50 diet [17, 18, 20]. As a genetic test of the role of dietary restriction, we fed skn 1 mutants the GD1 diet, since these mutants fail to respond to dietary restriction and are sensitive to oxidative stress [21]. SKN-1, a transcription factor homologous to

mammalian Nrf 1, plays a role in metabolic regulation and interacts with signaling systems that respond to changes in nutrition [22]. As shown in Figure 1, skn 1 mutants fed GD1 live longer than hatch-mates fed OP50. These results confirm that the GD1 diet imparts life span extension independently of effects related to dietary restriction. Figure 1 The oxidative stress sensitive skn-1(zu169) mutant, with defects in response to dietary restriction, shows a life span extension in response to the GD1 diet. Wild-type N2 (squares) and skn-1(zu169) −/− mutant worms (triangles) were fed either OP50 (black) (N2, n = 164; skn-1(zu169) −/−, n = 153) or GD1 (grey) (N2, n = 135; skn-1(zu169) −/−, n = 131) from the L4 stage. N2 worms fed GD1 showed a 67% increase in mean life span as compared to N2 worms fed OP50 (a, p < .0001). skn-1(zu169) −/− mutants fed GD1 showed a 50% increase in mean life span compared to N2 worms fed OP50 (a, p < .0001).