Abstract

The expression of five innate immune-related genes crustin (MjCrus), lysozyme (MjLyz), penaeidin (MjPEN), Toll-like Receptors (MjToll), and Tumor Necrosis Factor (MjTNF) in the lymphoid organ (LO) and intestine of kuruma shrimp (Marsupenaeus japonicus) was investigated after challenge with Vibrio nigripulchritudo. Bacteria (1 x 10⁵ CFU/ml) were injected into the second abdominal segment of the shrimp. The LO and intestine were isolated at 3, 12, 24, and 48 h post-injection, and total RNA was extracted. The expression of MjCrus, MjLyz, MjPEN MjToll, and MjTNF was determined by semi-quantitative RT-PCR. In the LO, expression levels of MjCrus, MjLyz, MjPEN, MjToll, and MjTNF were significantly higher in infected shrimp than in uninfected animals. The intestine of shrimp infected with V. nigripulchritudo exhibited higher expression of MjCrus, MjLyz, MjPEN, and MjTNF than did that of uninfected animals. However, intestinal MjToll expression levels were similar in both groups. These results suggested that MjCrus, MjLyz, MjPEN, MjToll, and MjTNF may play an important role in the immune defense of kuruma shrimp exposed to V. nigripulchritudo.

Key words: Kuruma shrimp Marsupenaeus japonicus, innate immune-related gene, infection, Vibrio nigripulchritudo.