P3.183 Friday, Jan. 6 High-throughput method for measuring muscle ultrastructure OLSZEWSKI, JM*; HARPER, CJ; BRAINERD, EL; Brown University, Providence, RI; Brown University, Providence, RI; Brown University, Providence, RI Julia_Olszewski@brown.edu
Traditionally, myofilament lengths have been measured using Transmission Electron Microscopy (TEM). This method is a time intensive process, making it difficult to use TEM for comparative research. The goal of this study is to develop a high-throughput, accurate method for measuring myofilament lengths that can be applied to vertebrates and invertebrates. Larval zebrafish (Danio rerio) muscle was processed for TEM using the traditional approach developed by Page and Huxley (1963); J Cell Biol 19(2):369-390. These authors established that myosin thick filament length is consistently 1.6 μm in diverse slow and fast vertebrate muscles. Here, myosin was immmunohistochemically labeled, and the muscle was optically sliced, then rendered three-dimensionally with a confocal microscope. Thick filament lengths were measured in the confocal images and compared to measurements from the electron micrographs. A preliminary analysis reveals that zebrafish thick filament lengths were 1.58 μm on the TEM micrographs and 1.54 μm on the confocal images. The accuracy of these measurements may be enhanced with the use of super resolution microscopy, which is becoming more common in bioimaging facilities. Because confocal microscopy is efficient, this method can be used to measure myofilaments lengths in a variety of organisms. In invertebrates, thick filament length is variable, even within the same animal. With this method, thick filament length could be measured across a wide range of invertebrate species and give insight into how muscle ultrastructure predicts muscle function.