Characterization and antimicrobial evaluation of a new Spgly-AMP, glycine-rich antimicrobial peptide from the mud crab Scylla paramamosain.

Antimicrobial peptide (AMP) is a crucial component of the innate immune system in crustaceans. In mud crab, Scylla paramamosain , a commercially important species, a glycine-rich antimicrobial peptide (Sp gly-AMP) gene was newly identified and putatively encoded a 26aa signal peptide and 37aa mature peptide. To understand the function of Sp gly-AMP, the expression profile of Spgly-amp gene was characterized, which showed Spgly-amp was expressed widely in most tissues of adult crabs with the highest expression level in hemocytes. After Vibrio parahaemolyticus , PGN, or Poly I:C stimulations, the expression level of Spgly - amp was significantly up-regulated in the hemocytes. In antimicrobial assays, chemically synthesized Sp gly-AMP peptides exhibited strong antibacterial activities against both Gram-positive and Gram-negative bacteria and high thermal stability after high-temperature heating. These findings in the present study verified the importance of the Sp gly-AMP in defense of pathogenic bacteria infection in the mud crab and provided a promising candidate of antimicrobial agents in the crab aquaculture. • A glycine-rich antimicrobial peptide (Sp gly-AMP) gene was newly identified from mud crab. • The orthologs of gly-AMP in several crabs are highly conserved. • After bacterial stimulations, the Spgly - amp mRNA was significantly induced in the hemocytes. • Sp gly-AMP peptides exhibit strong antibacterial activities and high thermal stability. [ABSTRACT FROM AUTHOR]