38th Annual Meeting of the Society for Invertebrate Pathology

Basic knowledge of shrimp immunity is needed to develop strategies for prophylaxis and control of diseases in shrimp aquaculture. To create a better understanding of shrimp immunity, this study was undertaken to clone and characterized α2-macroglobulin (α2M) and crustin-like peptide (antibacterial peptide) from kuruma shrimp Marsupenaeus japonicus. The cDNA encoding the M. japonicus α2M contains an open reading frame of 4,518 nucleotides that translate into a 1,505 amino acid putative peptide. In a healthy shrimp, the mRNA of α2M was mainly expressed in the haemocytes. Five variants (types 1 to 5) of M. japonicus crustin-like peptide cDNAs were obtained from a haemocyte cDNA library. M. japonicus crustin-like peptide type 1 has a cDNA of 679 nucleotides and an open reading frame (ORF) of 573 bp coding for 191 amino acid residues. Other types contained varying glycine-rich repeats at the N- terminal amino acid sequences. Expression of M. japonicus crustin-like peptide mRNA was detected in haemocytes, but not in heart, hepatopancreas, gill, fore-gut, mid-gut, muscle, subcuticular epithelium or ovary. The expression of α2M and crsutin mRNA were dramatically increased after peptidoglycan (PG) administration.