| Gq protein is a type of heterotrimeric G protein which is made up of α,β,γ . Gq protein which have been discovered recently exist in many invertebrate photoreceptor cells. The translocation of Gq α has been proposed as one of the molecular mechanisms to control photoreceptor sensitivity.Its role is molecular switch and signal amplification in photo-electro transduction. The last study of Gq α were focused on the identification of the Gq α type and the light effects on Gq α ,otherwise, the calcium effects on Gq α have not been reported. In our experiment, after light and dark adaptation, the retina of the Macrobrachium rosenbergi was respective incubated in high calcium solution, physiological solution and low calcium solution.We studied the effect of calcium concentration on the content and subcellular localization of Gq protein a subunit in the photoreceptor cell of Macrobrachium rosenbergi on light adaptation and dark adaptation by SDS-PAGE technology and Imunoelectron microscopy technology .Our study results indicated:一, Effects of calcium concentration on the soluble Gq protein a subunit in the photoreceptor cell of Macrobrachium rosenbergi on light adaptation and dark adaptation.The Soluble Gq α was extracted from the retina of the Macrobrachium rosenbergi with protein extract and was electophoresised by SDS-PAGE. The percent of the Soluble Gq α was analyzed by Tanon GIS gel image disposal system. After the incubation in three solutions, The Soluble Gq a in 42kDa was all extracted from photoreceptor cell. The percent of the Soluble Gq α in photoreceptor cell in high calcium solution, physiological solution and low calcium solution was 3.13%,3.09%, and 3.03% respectively on light adaptation and was 3.17%,3.06% and 3.01% respectively on dark adaptation. In physiological solution and low calcium solution ,the percent of the protein on light adaptation was higher than that on dark adaptation, but in low calcium solution, the percent of the protein on light and dark adaptation was no significantly different; in high calcium solution, the percent of the protein on dark adaptation was higher than thaton light adaptation .This was probably relevant to feedback regulation.二, Effects of calcium concentration on the Membrane-bound Gq protein a subunit in the photoreceptor cell of Macrobrachium rosenbergi on light adaptation and dark adaptation.The Membrane-bound Gq a was extracted from the retina of the Macrobrachium rosenbergi with protein extract and was electophoresised by SDS-PAGE. The percent of the Membrane-bound Gq a was analyzed by Tanon GIS gel image disposal system. After the incubation in three solutions, The Membrane-bound Gq a in 42kDa was all extracted from photoreceptor cell . The percent of the Membrane-bound Gq a in photoreceptor cell in high calcium solution, physiological solution and low calcium solution was 4.63%,4.58%, and 5.05% respectively on light adaptation and was 4.56%,4.94% and 5.13% respectively on dark adaptation. In physiological solution and low calcium solution ,the percent of the protein on dark adaptation was higher than that on light adaptation, but in low calcium solution, the percent of the protein on light and dark adaptation was no significantly different ; In high calcium solution, the percent of the protein on light adaptation was higher than that on dark adaptation.三, Effects of calcium concentration on subcellular localization of Gq protein a subunit in the photoreceptor cell of Macrobrachium rosenbergi on light adaptation and dark adaptation.Effects of calcium concentration on subcellular localization of Gq protein a subunit in the photoreceptor cell of Macrobrachium rosenbergi on light adaptation and dark adaptation were studied using immunogold electronmicroscopy. Our study results indicated:On light adaptation ,the ratios of the density of the gold particles in the rhabdom to that in the cytoplasm in Macrobrachium rosenbergi photoreceptor cell in high calcium solution, physiological solution and low calcium solution was 21/6, 1...
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