Activity of lysozyme from Oncomelania hupensis and its role in inhibiting bacteria: a preliminary study / 中国地方病学杂志

ABSTRACT

Objective To study the lysozyme activity in Oncomelania hupensis and observe its inhibitory effect on bacterial growth.Methods Soft tissues of Oncomelania hupensis were initially homogenized and immersed in Tris-HCl-TritonX-114 buffer solution for 24 hours then the supernatant was collected after centrifugation at 10 000 × g for 10 minutes.The supernatant was incubated in a 37 ℃ water bath for 15 minutes and centrifuged again at 2000 × g for 10 minutes.The precipitate was put into ultrafiltration tube (relative retention molecular mass =3000) and centrifuged at 4 ℃,5 000 × g for 30 minute to obtain concentrated enzyme.The protein content,lysozyme activity and the antibacterial effect on Micrococcus lysodeikticus,Shigella dysenteriae,Staphylococcus aureus,Escherichia coli and Candida albicans were measured with bicinchonininc acid(BCA) method,turbidimetric method and agar diffusion (K-B) method,respectively.Results The antibacterial protein lysozyme was identified in gastropod protein concentration of the concentrated enzyme was 3.428 g/L.Average activity,total activity,and specific activity were (760 ± 120) × 103 U/L,(1520 ± 240) × 103 U/L and (221.70 ± 35.00)U/mg,respectively.The enzyme had produced exclusive inhibitory effects on growth of Micrococcus lysodeikticus and Shigella dysenteriae.Average inhibitory diameters were 10-12 and 12-15 mm,respectively.No inhibition zone was observed in saline control,Staphylococcus aureus,Escherichia coli and Candida albicans.Conclusions Lysozyme can be extracted from soft tissues of Oncomelania hupensis with Tris-HCl-TritonX-114 buffer solution,and the enzyme has inhibitory effect on growth of Micrococcus lysodeikticus and Shigella dysenteriae but has no antibacterial effect on Staphylococcus aureus,Escherichia coli and Candida albicans.