Fig. 2.

Autophagy is needed for lifespan extension at low temperature. a–c bec-1 RNAi significantly reduced lifespan of worms at 15 °C (Log-rank test, P < 0.01 versus EV), but not 20 °C, and 25 °C. EV, empty vector. See Supplementary Data 1 for details. d, e Autophagy is involved in delaying the appearance of the aging markers, including pharyngeal pumping (d) and body bending (e), in worms at 15 °C, but not 20 °C. These results are means ± SD (n = 20). Ten worms were examined per experiment. *P < 0.05, 8-day-old worms with EV at 15 °C versus 8-day-old worms with EV at 20 °C; **P < 0.01, 8-day-old worms with EV at 15 °C versus 8-day-old worms with bec-1 RNAi at 15 °C. ns, not significant. f Aging marker lipofuscin autofluorescence. These results are means ± SD of three independent experiments (n = 30–34 worms per experiment). *P < 0.05, 8-day-old worms with EV at 15 °C versus 8-day-old worms with EV at 20 °C, or 8-day-old worms with bec-1 RNAi at 15 °C. ns, not significant. P-values (d–f) were calculated using a one-way ANOVA followed by a Student-Newman-Keuls test. Scale bars: 100 μm