Dual excitation-emission fluorescence/contractility system

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The requested equipment will support three research programs: 1) the mechanism of macrophage fusion that leads to the formation of multinucleated cells such as osteoclasts for bone resorption and giant cells during an immune response; 2) the regulation of the glucose transporter activity in pancreatic ß-cells, which secrete insulin when plasma glucose is too high; and, 3) the protective mechanism of the ATP sensitive potassium channel during exercise and fatigue in skeletal muscle.     All three studies first require a setup that quantifies fluorescence for the measurements of intracellular ion in living cells. More specifically, we need i) an imaging system for the studies involving macrophages and ii) photomultiplier tubes (PMTs) to measure total fluorescence in ß-cells and single muscle fibers. Furthermore, the setup must have the capability to switch between two excitation wavelengths within msec when intracellular calcium is measured with fura-2, a fluorescent indicator, because contractions last less than 200 msec. The system must also be capable of measuring emission light at two different wavelengths for intracellular hydrogen ion with SNARF. Finally, for the study involving muscles, our single fibers are isolated after a digestion of collagen; so, these fibers cannot be attached to a force transducer because they have no tendon left. We therefore measure sarcomere shortening as an index of contractility.     The IonOptix dual excitation-emission fluorescence / contractility system comprise a hyperswitch that alternate between two emission wavelengths, two PMTs to measure total fluorescence, two cameras one for the imaging analysis and another for sarcomere shortening. The system is highly versatile allowing through the included software to switch between the imaging system and PMTs or to simultaneously measure intracellular ion and sarcomere length.