Identification of a spontaneous E. coli mutant that extends lifespan. A) Survival curves of rrf-3(pk1426); daf-2(m577) animals at 25°C on the control strain (n = 201): HT115(DE3) containing the empty vector L4440 and a strain, containing the plasmid for the ugt-27 gene, that caused a 50% increase in lifespan (n = 92, P = < 0.0001). B) Survival of rrf-3 (25°C) on the mutant strain from which the ugt-27 has been lost (n = 68) compared with the control strain in which the L4440 empty vector has been lost (n = 62). Increase in lifespan = 49.6% (P = < 0.0001). C) Position of the IS1 transposon insertion at position 1777116 on the E. coli K12 W3110 chromosome  (diagram based on EcoCyc.org ). As the insertion is at nucleotide 717 of the aroD open reading frame, the allele is designated aroD717::IS1. D) The lifespan effect of the mutant bacteria is rescued by the plasmid containing aroD. glp-4(bn2) animals were raised on the aroD mutant until L4 (15°C) and then transferred to the aroD mutant + pMMB67EH vector (n = 126), aroD mutant + pMMB67EH plasmid containing aroD region (n = 85), wild type bacteria + vector (n = 126) (25°C). E) Worms maintained on the aroD deletion mutant from the Keio collection (n = 128) show an extended lifespan compared to wild type (n = 131). P = < 0.001.