Thymosins participate in antibacterial immunity of kuruma shrimp, Marsupenaeus japonicus.

Abstract Thymosins β are actin-binding proteins that play a variety of different functions in inflammatory responses, wound healing, cell migration, angiogenesis, and stem cell recruitment and differentiation. In crayfish, thymosins participate in antiviral immunology. However, the roles of thymosin during bacterial infection in shrimp remain unclear. In the present study, four thymosins were identified from kuruma shrimp, Marsupenaeus japonicus , and named as Mj thymosin2, Mj thymosin3, Mj thymosin4, and Mj thymosin5 according the number of their thymosin beta actin-binding motifs. Mj thymosin3 was selected for further study because its expression level was the highest in hemocytes. Expression analysis showed that Mjthymosin3 was upregulated in hemocytes after challenged by Vibrio anguillarum or Staphylococcus aureus. The recombinant Mj thymosin3 protein could inhibit the growth of certain bacteria in an in vitro antibacterial test. Mj thymosins could facilitate external bacterial clearance in shrimp, and were beneficial to shrimp survival post V. anguillarum or S. aureus infection. The results suggested that Mj thymosins played important roles in the antibacterial immune response of kuruma shrimp. Highlights • Four thymosins were identified from kuruma shrimp, Marsupenaeus japonicus. • Mjthymosin3 was upregulated in hemocytes after challenge by V. anguillarum or S. aureus. • R Mj thymosin3 could inhibit the growth of certain bacteria. • Mj thymosins could facilitate external bacterial clearance in shrimp. • Mj thymosins were beneficial to shrimp survival post V. anguillarum or S. aureus infection. [ABSTRACT FROM AUTHOR]