Effect of cooling on the first myosin layer line (ML1). (A) Axial profiles (parallel to the meridional axis) of the mixed myosin (ML1) and actin (AL1) layer line reflection in intact trabeculae at five relevant temperatures. Magenta, 39°C; orange, 28°C; green, 22°C; cyan, 16°C; blue, 7°C. Data added from n = 5 intact trabeculae. (B) Corresponding profiles in demembranated trabeculae in the presence of Dextran. Data added from n = 4 demembranated trabeculae. Vertical continuous and dashed line, ML1 and AL1 spacings, respectively, as estimated in Brunello et al. (2020). (C) Intensity of ML1 reflection (IML1). Gray circles and line, intact trabeculae; empty circles and dashed black line, demembranated trabeculae in the absence of Dextran; black circles and continuous line, demembranated trabeculae in the presence of 3% Dextran. Mean ± SE; n = 5 intact trabeculae and n = 4 demembranated trabeculae. Data for intact trabeculae are normalized by the IML1 value at 39°C. Data for demembranated trabeculae are normalized by the IML1 value at 38°C in the presence of Dextran. a.u., arbitrary unit.