鲎素对嗜水气单胞菌的抑菌活性及作用机制研究

为探讨鲎素对嗜水气单胞菌的抑杀作用,采用最小抑菌浓度、AB染料、扫描电镜、流式细胞仪和琼脂糖凝胶电泳等方法研究鲎素对嗜水气单胞菌的抗菌活性、杀菌率、胞内紫外物质泄露、膜负电荷数、外部形态结构及胞内基因组DNA的影响。结果表明,鲎素对嗜水气单胞菌的抗菌活性较其他细菌弱;2倍最低杀菌浓度(MBC)鲎素能在短时间内迅速杀死嗜水气单胞菌并导致胞内生物大分子泄漏;扫描电镜发现1倍MBC鲎素能导致轻微的壁膜破损及一些胞内物质渗出和粘连;流式细胞仪结果表明,1倍MBC鲎素能破坏细胞膜的完整性;AB染料测定表明鲎素处理后能改变膜负电荷数;琼脂糖凝胶电泳表明,鲎素能够与嗜水气单胞菌的基因组DNA发生作用,并呈浓度依赖关系,浓度越高对细菌基因组DNA损伤越大。鲎素对嗜水气单胞菌的抑菌活性弱,只有高浓度时才能短时间内导致胞内紫外吸收物质泄露、膜负电荷数发生改变及基因组DNA损伤。

Study on Antibacterial Activity and Action Mechanism of Tachyplesin I against Aeromonas hydrophila

The antimicrobial role of tachyplesin I on Aeromonas hydrophila was investigated.The effects of tachyplesin on the antimicrobial activity,the sterilization rate,intracellular UV substance leakage,mem-brane negative charge number,external morphological structure and intracellular genomic DNA of Aero-monas hydrophila were determined by minimum inhibitory concentration,AB dye,scanning electron mi-croscope,flow cytometry and agarose gel electrophoresis methods.Compared with other bacteria,the anti-microbial activity of tachyplesin for Aeromonas hydrophila was relatively weaker.2MBC tachyplesin could killed rapidly Aeromonas hydrophila and lead to large biological molecule leakage in a short period of time. The result of scanning electron microscopy showed that 1MBC tachyplesin could lead to membrane damage slightly and cellular content outflow.Flow cytometry results showed that 1 MBC tachyplesin can damage the integrity of cell membrane.Tachyplesin could change the membrane negative charge number through AB dye determination.Tachyplesin had effect on the genomic DNA of Aeromonas hydrophila in a concen-tration-dependent manner by agarose gel electrophoresis determination.Tachyplesin had weak antibacterial activity on Aeromonas hydrophila ,and only high concentrations can make membrane negative charge num-ber change,intracellular UV substance leakage and genomic DNA damage in a short time.