Studies On The Photoreceptor And The G-protein Of The Photoreceptor In The Two Kinds Of Crustacean

G protein coupled signal transduction is major transmembrane signaling pathways in cell. In animal photoreceptor, G protein plays an important role in signal transduction and magnification. The involvement of Gq proteins in invertebrate phototransduction has been shown in many invertebrate. But the study of G protein in Crustacean photoreceptors was few in internal and abroad. It was not known that whether the Gq protein is popularly in Crustacean photoreceptors, or there are other kinds of G protein in those, and characters and functions of Gq protein. In this paper, the photoreceptor and the G-protein of the photoreceptor in the two kinds of Crustacean, Cherax quadricarinatus and Macrobrachium nipponense, were studied with histological methods ,electron microscopy (EM), biochemstry methods and immunoelectron microscopy. The purpose is the functions of Gq protein in phototransduction under the illumination by different light condition, and to accumulate dasal information for animal photoreceptive physiology in molecule levels.1. Morphology and Ultrastructure of the Compound Eye in Cherax quadricarinatusWe studied the morphology and fine structure of the compound eye in Cherax quadricarinatus by histological section methods and electron microscopy (EM) . The results showed : The compound eye of Cherax quadricarinatus is semi-globular. On the back of the compound eye there is a thumb-shaped area which have no ommatidia. The ommatidia that form the compound eye are rectangle. The area of an ommatidium is 3723.5um2. The surface area of the compound eye is about 21.044mm2.An ommatidium composed of cornea, four corneagenous cells, four cone cells and retinular cells. The sensitization system of an ommatidium included 11 retinular cells, of which four located at the distal part of the ommatidium; seven formed the proximal main part of the retina. The two parts are some one on top of another. Their structures are different, the cytoplasm of the distal retinular cells is more compact than that of the proximal cells, but the numbers and kinds of the organelles of the distal retinular cells are less. Our results show that the photoreceptorof Cherax quadricarinatus has two kinds retinular cells that have different function.2.The Influence of Light and Dark Adaptation on the infrastructure of the Photoreceptor in Cherax quadricarinatusThe Ultrastructure of the photoreceptor in Cherax quadricarinatus, which was in light and dark adaptation, was studied by electron microscopy. During light adaptation, the diameter of rhabdoms was small, the arrangement of microvillus in the distal rhabdom was in disorder, and the area of the multivescicular bodies in the cytoplasm of the retinular cells was large, but the perirhabdomal vacuoles was very small, the amount of the lamellar bodies and mitochondrias were small, the pigment granules were distributed in all retinular cell. However, during dark adaptation, the diameter of rhabdoms was bigger than that of rhabdoms was at light adaptation, the arrangement of microvillus in the rhabdom was tidy, the area of the perirhabdomal vacuoles was big in the cytoplasm of the retinular cells. The multivescicular bodies,lamellar bodies and mitochondrias were more than those were at light adaptation. The pigment granules located only in distal and proximal region of the retinular cell.3. Morphology and Ultrastructure of Compound Eyes in the larval stages of Cherax quadricarinatusMorphology and Ultrastructure of Compound Eyes was investigated by TEM and SEM in the larval stages of Cherax quadricarinatus. The result is indicated: Morphology of compound eye and ommatidium in the larval stage were similar to that in adult stage. The area of the ommatidia increases from 906+29.6 um2 in larva I (1.5cm long )to 967+53.3 um2 in larva in(3cm long) and 3724+230.3um2 in adult (16cm long ) .The number of the ommatidia in a compound eye varies with the development from about 1001 in larva I to about 1238 in larva III and 5652 in adult. The increase of the area of the compound eyes in Cherax quadr...