Contraction of the DLM1 flight muscles of the Hawmoth, Manduca sexta are synchronous with the nervous impulse stimulation like mammalian... Show moreContraction of the DLM1 flight muscles of the Hawmoth, Manduca sexta are synchronous with the nervous impulse stimulation like mammalian skeletal muscle. With cardiac-like behavior, DLM1 muscle of Manduca sexta can be a useful model to resemble mammalian cardiac muscle. Asynchronous flight muscles, like Lethocerus and Drosophila flight muscle, can only extend a few percent. But Manduca flight muscle has the ability to extend at least 100% in vitro and 9% in vivo. Very little is known about the protein composition and physiological behavior of Manduca flight muscle. Hence the length-tension behaviors of the DLM1 muscle of Manduca sexta are of considerable interest. In this experiment, we used PPi to remove thick filament in the sarcomere and focus on the passive tension generated by elastic proteins (projectin, kettin and sls proteins) in the sarcomere. The results showed elastic proteins (projectin, kettin and sls proteins)-based passive tension play a major role on muscle passive force in DLM1 muscles of Manduca sexta. We also tested a new way to prepare chemically skinned muscle samples where the dorsal and ventral muscle samples are pinned still in their shell on plates during the skinning step. In addition, preliminary experiments attempting to purify the DLM1 muscle proteins of Manduca sexta, fast protein liquid chromatography was used. Then 1% vertical SDS-agarose gel electrophoresis (VAGE) and 4-20% SDSPAGE gel are used to detect the samples after purification. We successfully purified 900kDa projectin and 700kDa kettin, which are major elastic proteins and useful for further research. M.S. in Biology, May 2014 Show less
