中华真地鳖抗菌物质的抑菌活性测定

Antibacterial Activity of the Substances in the Eupolyphaga sinensis

以研磨法从中华真地鳖五龄若虫体内提取得到抗菌物质，分别采用比浊法和菌碟法测定了其对多种细菌和植物病原真菌的抑菌活性。结果表明，该抗菌物质对大肠杆菌、金黄色葡萄球菌、白菜软腐菌和枯草芽孢杆菌等4种细菌生长均有一定的抑制作用，对数期延迟1—4h，菌的浓度、繁殖速度减缓。对7种植物病原真菌的抑茵试验表明，该抗菌物质对玉米茎基腐病菌、小麦根腐病菌、棉花枯萎病菌抑制效果较好，抑制率分别为50．0％、49．2％、45．2％；而对白菜黑斑病菌和玉米大斑病菌活性较差，抑制率仅为28．3％和24．5％。

In this paper, the peptides obtained from Eupolyphaga sinensis were tested for antimicrobial activities against bacteria and plant pathogens. Immunized hemolymph was prepared from fifth-instar larvae of E. sinensis by pricking with Escherichia coli. Antimicrobial peptides were obtained by means of grinding, dialysis and concentration. Tests of growth inhibition and nephelometry assay indicated that definite antibacterial activities against E. coli, Staphylococcus aureus, Erwinia carotovora and Bacillus subtilis. Their logarithm growth periods were postponed for 1 h to 4 h. The inhibition tests on fungi demonstrated that inhibition rates to Alternaria porri, Fusarium oxysporium, Cochliobolus sativus were 50.0% to 41.0%.