Figure 1.

Decreased Fractional Shortening in w¹¹¹⁸ Correlates with Decreased Longevity and Increased BM Thickness. (A) Fractional shortening was calculated for each genotype and age (mean ± s.e.m., n=20) and is plotted at 1 and 5 weeks. * p<0.05 (B) Survival curves for indicated wildtypes show median survival indicated by the dashed black line for each genotype, 55 and 35 days for yw (n=215) and w¹¹¹⁸ (n=223), respectively. ***p<0.001. (C) Brightfield image of AFM cantilever (open triangular shape) positioned over midline (center) of the Drosophila heart tube during nanoindentation analysis of Drosophila tri-layered myocardium. Scale bar is 100 µm. (D) Schematic of 3 layered AFM nanoindentation (black circle) into Drosophila heart tube depicting: (i) the 1^st layer indentation of the VM, (ii) the complete compaction of the VM layer and 2^nd layer indentation of the BM, and (iii) the final compaction of the first 2 layers and 3^rd layer indentation of the CM layer. (E) A representative force vs. indentation depth plot in black showing the respective Linearized-Hertz fits for both the shallow (green) VM and deep (red) CM with a BM layer indicated by a linear region shown in blue starting and ending within the brackets. (F) BM stiffness and BM thickness reported as the length over which the BM linear region was fit were measured by AFM at the ventral midline and plotted at indicated ages. All data represented as mean ± s.e.m of >15 flies.*p<0.05 and **p<0.01 for indicated comparisons.