JOHNSON, G.P.; DANGLE, D.D.; WOLFE*, A.F.; Lebanon Valley College; Lebanon Valley College; Lebanon Valley College: Morphological Study of Artemia Hemocytes During the Molting Cycle

Although most crustaceans have several different types of blood cells, the anostracan, Artemia franciscana, has a single type of granular hemocyte in its hemolymph. Using various stains, microscopic techniques, and gel electrophoresis, we focused on the structure of these hemocytes, especially the composition of the granules and their possible functions during the molting cycle. The tanning of the crustacean exoskeleton involves quinones and the phenoloxidase enzyme cascade. In Artemia phenoloxidase has been demonstrated in hemocytes; however, it has not been correlated with the tanning of the exoskeleton. Our earlier work showed variability of the hemocytes to utilize this enzyme system. By studying shrimp at different times during the 5 day molt cycle, we observed the cyclic increase of tyrosine within the hemocytes with a maximum during days 1 and 5, when quinones are necessary for tanning the exoskeleton. Unlike decapod crustaceans, Artemia hemocytes were never found in the molting fluid between the epidermis and new exoskeleton. Although some granular material was dispersed near the exoskeleton, they were not hemocyte granules. At the TEM level the contents of granules consist of at least 2 different components. None of the granular material near the exoskeleton resembled the hemocyte granules. Results of 2-D electrophoresis have shown several neutral proteins isolated from the hemolymph serum. It appears that the hemocytes regulate the amount of substrate, tyrosine, entering the cell in a cyclic fashion. This increased quantity of tyrosine combined with the phenoloxidase in the hemocyte granules could provide the necessary quinones for tanning the exoskeleton just after molting.