Characterization And Expression Of C-Type Lysozyme cDNA From Kuruma Shrimp (Penaeus japonicus)     Sonomi Minagawa1, Jiraporn Rojtinnakorn1, Jun-ichi Hikima2, Ikuo Hirono1, and Takashi Aoki1   1 Laboratory of Genetics and Biochemistry, Department of Aquatic Biosciences, Tokyo University of Fisheries, Konan 4-5-7, Minato-ku, Tokyo 108-8477, Japan 2 Present address: Department of Biochemistry of Molecular Biology, Medical University of South Carolina, 173 Ashley Avenue, POB 250509, Charleston SC     Lysozyme is widely distributed in the serum, skin mucus and organs of fish and plays an important role in bio-defence systems.  A c-type of lysozyme cDNA was cloned from a hemocyte cDNA library of the kuruma shrimp (Penaeus japonicus).  The cDNA of the kuruma shrimp c-type lysozyme consisted of 1,055 bp, which coded for 156 amino acid residues.  The deduced amino acid sequence of kuruma shrimp lysozyme possessed?46% homology with mouse and 43% homologies with Japanese flounder, rainbow trout, chicken, and human c-type lysozymes.  Comparison of the c-type lysozymes showed that the catalytic residues and the cycteine residues were completely conserved.  Furthermore, we expressed the kuruma shrimp c-type lysozyme cDNA in insect cells using baculovirus expression system and evaluated the activity of the recombinant lysozyme.  The activity of the recombinant kuruma shrimp lysozyme was detected using a lysoplate assay.  We are currently investigating the optimum pH and temperature of this recombinant lysozyme and the lytic activity against several bacterial pathogens.