Characterization of a C-Type Lectin Domain-Containing Protein with Antibacterial Activity from Pacific Abalone ().

Genes that influence the growth of Pacific abalone () may improve the productivity of the aquaculture industry. Previous research demonstrated that the differential expression of a gene encoding a C-type lectin domain-containing protein (CTLD) was associated with a faster growth in Pacific abalone. We analyzed this gene and identified an open reading frame that consisted of 145 amino acids. The sequence showed a significant homology to other genes that encode CTLDs in the genus . Expression profiling analysis at different developmental stages and from various tissues showed that the gene was first expressed at approximately 50 days after fertilization (shell length of 2.47 ± 0.13 mm). In adult Pacific abalone, the gene was strongly expressed in the epipodium, gill, and mantle. Recombinant Pacific abalone CTLD purified from exhibited antimicrobial activity against several Gram-positive bacteria (, , and ) and Gram-negative bacteria ( and ). We also performed bacterial agglutination assays in the presence of Ca, as well as bacterial binding assays in the presence of the detergent dodecyl maltoside. Incubation with . and . cells suggested that the CTLD stimulated Ca-dependent bacterial agglutination. Our results suggest that this novel Pacific abalone CTLD is important for the pathogen recognition in the gastropod host defense mechanism.