Effect of growth temperature on the steady-state fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene incorporated into flight muscle mitochondrial membranes of houseflies (Musca domestica)

This study reports steady-state measurements of the fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) within flight muscle mitochondrial membrane fragments from adult houseflies (Musca domestica) grown at 15 and 25 °C. Growth temperature of the houseflies is shown to have no effect on the polarization of DPH's fluorescence, whereas the temperature sensitivity of fluorescence polarization (Δ polarization) is 16% higher in flies grown at 25 °C than in those grown at 15 °C. Since the fluorescence polarization of DPH gives an indication of the degree of order within membranes, these results suggest that houseflies have the ability to alter the temperature dependence of their flight muscle mitochondrial membrane structure in response to a change in temperature. Little attention has been directed to the effects of growth temperature on Δ polarization values and this study suggests a procedure for detecting the existence of changes in this quantity.