Identification Of Catfish Mucus Antimicrobial Peptide And The Study Of Inhibitory Mechanism For Pathogenic Bacteria In Aquatic Product

In recent years,the fish surface mucus antibacterial peptides,which are important antimicrobial active components,can play a direct inhibitory effect on microbiology.We isolated the antimicrobial peptides from catfish mucus and identified the antibacterial peptide sequence.The effect of catfish epidermal mucus extraction on physicochemical and microbial characteristics of grass carp fillets was investigated during 4? storage.1.The antibacterial active substance was extracted and the antibacterial activity on the tested strains was tested.The results showed that the extractions of catfish mucus exhibited a broad-spectrum antibacterial activity and a better stability.The antibacterial peptides were purified by the Sephadex G-25 gel filtration chromatography,solid-phase extraction,freezing concentration and reversed-phase high-performance liquid chromatography(RP-HPLC)and then the primary structure of protein was measured.The amino acid sequences of ABPs were RIVELTLPRVSVRL,KQEIILKF,RQIKIXRR and RLKEKNKA2.In this study,several methods were utilized to investigate the antibacterial activities and mechanism of ABPs against E.coli and S.aureus.ABPs could decrease bacterial growth rate.The morphology changes of bacteria treated with ABPs were investigated by scanning electron microscopy(SEM),which indicated that the primary inhibitory action of ABPs was to damage bacterial cell membranes and caused cell membrane's diffusion.In addition,ABPs could make obvious change on bacterial proteins and membrane protein.3.The effect of catfish epidermal mucus extraction on physicochemical and microbial characteristics of grass carp fillets was investigated during 4? storage.The results revealed that ABPs could retard the change of the TVB-N value,pH value,K-value,chromatic aberration value,volatile odor and volatile flavor components.In addition,ABPs could restrain effectively the growth of the microorganism.The results showed that ABPs could more effectively maintain the good quality of grass carp fillets.