Expression Profiles of Zebrafish () Lysozymes and Preparation of c-Type Lysozyme with High Bacteriolytic Activity against .

Lysozyme is a crucial component of the host's innate immune system. Due to its natural non-toxic and harmless characteristics, lysozyme is considered to be an ideal antibiotic substitute. In this study, we analyzed the expression profiles of lysozymes from zebrafish () in uninfected or -infected tissues using real-time quantitative PCR (qPCR). Furthermore, lysozymes that might be involved in the defense against were selected for over-expression, and the antibacterial activity of over-expressed lysozyme proteins were evaluated using . The results showed that three types of zebrafish lysozyme, i.e., c-type lysozyme (DrLysC), g1-type lysozyme (DrLysG1), and g2-type lysozyme (DrLysG2), were identified, and infection significantly changed the expression levels of DrLysC and DrLysG1. Then, DrLysC and DrLysG1 were over-expressed in , and the purified recombinant DrLysC (rDrLysC) showed more potent antibacterial activity against . This finding lays the foundation for further application of rDrLysC to treat infection.