Cadmium RadioisotopesSpectrometry, X-Ray EmissionFluorescenceSpectrometry, FluorescenceMicroscopy, FluorescenceFluorescence PolarizationIn Situ Hybridization, FluorescenceFluorescent DyesGamma RaysFluorescence Resonance Energy TransferFluorescence Recovery After PhotobleachingElasmobranchiiSkates (Fish)Microscopy, Fluorescence, MultiphotonGreen Fluorescent ProteinsTryptophanEnergy TransferLuminescent ProteinsKineticsRhodaminesFluoresceins