A study on antibacterial activity of antibacterial substance induced by Lucilia sericata at different pH conditions

Objective To investigate the antibacterial activity of antibacterial substance in Lucilia seri-cata induced by pricking the skin of maggots(fly s larvae)at different pH conditions. Methods The hemo-lymph from the third instar maggots was collected 48 h after pricking,and the antibacterial effect was tested a-gainst Micrococcus lysodeikticus and Staphylococcus aureus on plates at different pH conditions.The antibacterial effect against M.1ysodeikticus was also detected after the hemolymph、was diluted by different pH buffer solu-tions.The bacteriostatic effects were observed after 24 h and the diameters of clear inhibitory ring were recorded to express antibacterial activity. Results The antibacterial activity of the maggot hemolymph against M.lyso-deiktics and S.aureus was stronger on the plates at pH 6.0 and pH 6.5 than that on the other plates.In the group diluted by pH 6.0 buffer solutions.the antibacterial ring of the maggot hemolymph against M lysodeiktic-us was larger than that in others. Conclusion The results implied that the induced antibacterial substance in Lucilia sericata exhibited stronger antibacterial activity under acidic condition. Key words: Lucilia sericata; Antibacterial substance; Induction; pH