Genes Expressed In The Lymphoid Organ of Australian Banana Prawn (Penaeus merguiensis) Displaying Spheroid Cells
Spheroid formation in the lymphoid organ is suggested to be a major defence mechanism against viral infection in penaeids. Spheroids were observed in a hatchery population of banana prawns (Penaeus merguiensis), while these mechanisms were not identified in the wild population. Suppression subtractive hybridization cDNA forward libraries were constructed to profile upregulated expressed genes in the lymphoid organ of the hatchery population. A total of 316 sequenced clones were clustered into 141 contigs and 51.6% of the clones shared significant similarities to known peptide or nucleotide sequences in the GenBank (NCBI) database. These transcripts were assigned into 8 categories, including immune related genes (2.5%), synthesis, processing and regulation-related proteins (4.4%), ribosomal proteins (6.3%), proteases and inhibitors (7.0%), energy and metabolism factors (7.3%), structural and cytoskeletal related proteins (10.1%) and other sequences (13.9%). Many sequenced clones (48.4%) from the libraries have no significant similarity to amino acids/nucleotides in the public database revealing the ability of this method in disclosing new differentially expressed genes in the lymphoid organ of prawns. Furthermore, polymerase chain reaction (PCR) results revealed that spheroid cells in the hatchery population were probably linked to infection with Penaeus merguiensis hepandensovirus (PmeDV) which maybe the senior synonym of lymphoidal parvovirus (LPV).