WOLFE, A.F.; JOHNSON, G.P.; Lebanon Valley College: Histochemical and Ultrastructural Study of Artemia Hemocytes

While most animals, including the crustaceans, usually have several different types of blood cells within their vascular fluid, Artemia franciscana, an anostracan crustacean, appears to have a single type of granular hemocyte in its hemolymph. Using various types of histochemical staining, fluorescence microscopy, and electron microscopic techniques and gel electrophoresis, this study focused on the structure of these hemocytes, especially the composition of the granules and their possible functions. The hemocytes are approximately 9 �m in diameter and are usually disc-shaped with a smooth surface. The cytoplasm contains a large number of randomly distributed 3 �m granules and many mitochondria, usually surrounding these granules. The granules appear to contain a homogeneous material that stains positive for protein and elastin. However, with the addition of L-DOPA or L-tyrosine, a dark brown area appears to arise from one or few granules while the rest of the granules are unstained. At the TEM level the contents of granules appear to consist of at least two different components; one is much more electron dense. Using gel electrophoresis we found several bands of these granule proteins that were different from the bands in the hemolymph. The granule proteins had molecular weights of 57, 68, 87, and 92 kilodaltons. Although the hemocytes appear identical morphologically, the varied staining reactions suggest the possibility of more than one type of hemocyte in Artemia.