Fig. 3: AFM identifies differences in stiffness and cuticle senescence with age among diverse dietary restriction regimens. | Nature Communications

Fig. 3: AFM identifies differences in stiffness and cuticle senescence with age among diverse dietary restriction regimens.

From: Mechanical properties measured by atomic force microscopy define health biomarkers in ageing C. elegans

Fig. 3

a Lifespan curves of wild-type (WT) (blue), or eat-2 (green) and phm-2 (purple) feeding impaired mutant C. elegans (n = 98, 104 and 125, respectively; log rank test p < 0.001 vs fully-fed WT) and b longitudinal study of mechanical properties as Young’s Modulus (YM; kPa) until mean lifespan (D18 for WT; D23 for eat-2 and phm-2). Error bars indicate 95% CI, dotted lines mark mean YM at day 1 for WT (blue), eat-2 (green) or phm-2 (purple). Two-tailed unpaired t test for statistical comparison of WT with eat-2 or phm-2 at chronological age day 12 and at mean lifespan, WT at mean lifespan to day 1 (blue), phm-2 at mean lifespan to day 1 (purple), and eat-2 at mean lifespan to day 1 (green). c Lifespan curve of untreated (0 mm) (blue) and metformin-treated (50 mm) (red) WT C. elegans grown on sensitive OP50 (full line) or grown on metformin-resistant OP50-MR (dotted line). (n = 107, 142, 119 and 175, respectively; log rank test p < 0.001, p = 0.0883 and p = 0.0004 vs OP50 0 mm) and d mechanical properties as YM (kPa) at chronological age of 16 days. Error bars indicate 95% CI. Two-way ANOVA Tukey’s multiple comparison test for statistical comparison and interaction of terms (green). e Longitudinal study of mechanical properties as YM (kPa) of untreated (0 mm) (blue) and metformin-treated (50 mm) (red) WT C. elegans until mean lifespan (D18 for WT; D24 for metformin-treated). Error bars indicate 95% CI, dotted lines mark mean YM at day 1 for untreated (blue) and metformin-treated (red). Two-tailed unpaired t test for statistical comparison of untreated to metformin-treated at chronological age day 10 and mean lifespan. f Representative AFM cuticle topography images of WT, eat-2 and phm-2 mutant worms, and WT under bacterial deprivation or metformin-treated at mean lifespan. g Roughness quantification of topographical images presented as RMS roughness Rq ± standard deviation. Two-tailed unpaired t test for statistical comparison of WT with mutants/conditions. n represented above the graph, show number of biologically independent worm samples. For lifespan measurements, n represents the number of worms scored as dead. For a summary of YM values and additional statistics for independent trials, see Supplementary Data 1 and for a summary of worm lifespan trials and statistical comparison between genotypes see Supplementary Data 2. Source data are provided as a Source Data file.

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