Using as a Host Cell to Express an Antimicrobial Peptide from the Marine Chordate .

molecule against microbes-A24 (CiMAM) isolated from the marine chordate is an antimicrobial peptide. To generate CiMAM-expressing transgenic , we constructed a plasmid expressing recombinant CiMAM (rCiMAM) and introduced it into Transgenic strains C117 and C166 were selected since they were able to highly and stably express rCiMAM. We studied the bactericidal activity of pepsin-digested extracts from rCiMAM-expressing strains against freshwater and euryhaline pathogens that commonly occur in aquaculture ponds and found no difference from that of lactoferricin-expressing strains. The bactericidal activity of 1-μL aliquot from a total 5.5 mL extracted from 5 mL of cultured C117 (1.45 × 10 CFU·mL) and C166 (2.17 × 10 CFU·mL) against halophilic bacteria was equivalent to the efficacy of 57.06 and 32.35 ng of Tetracycline against , 47.07 and 25.2 ng against , and 58.17 and 36.55 ng against respectively, indicating higher bactericidal activity of pepsin-extracts from rCiMAM-containing strains against halophilic bacteria compared to that from lactoferricin-containing strains. Since the antibacterial activity of rCiMAM-expressing strains shows higher competence against halophilic pathogens compared to that against freshwater and euryhaline pathogens, these strains are promising candidates to protect marine fish and shellfish from halophilic bacterial infection.