The flight muscle of Manduca sexta has some interesting properties. It is synchronous, like mammalian skeletal and cardiac striated muscle,... Show moreThe flight muscle of Manduca sexta has some interesting properties. It is synchronous, like mammalian skeletal and cardiac striated muscle, but it is structurally similar to the more widely studied asynchronous insect flight muscles of Drosophila and Lethocerus. One of the main goals of the thesis is to generate a useful skinned preparation for mechanical studies in vitro. A number of different skinning protocols were tried and evaluated for preservation of structural integrity by using light and X-ray diffraction. In all muscles studied to date, isometric force is a function of the [Ca2+] of the bathing solution and also a function of the sarcomere length whereby more force is generated at a longer sarcomere length than at a shorter for the same [Ca2+]. This phenomenon is termed “length dependent activation” (LDA). To date no real studies on the force-pCa relationship has been done on Manduca sexta flight muscle. This force-pCa analysis would give us some insight into the length dependent activation (LDA) in this novel insect flight muscle system. The present studies were undertaken to characterize and analyze the force-pCa relationships in Manduca sexta. Conditions were found that allowed skinning muscles while maintaining good structural order. We found that both DLMs dorsal and ventral show length-dependent activation at longer SL. Our study also shows that ventral muscles are more cooperative than the dorsal muscles which may be related to their different functions in vivo. M.S. in Biological, Chemical, and Physical Sciences, July 2011 Show less
