克氏螯虾壳聚糖对细菌表面作用机理研究

Mechanism Analysis of Effect of Chitosan from Redswamp Crayfish on Bacterial Cell Surface

目的:研究克氏螯虾壳聚糖对细菌表面的作用机理。方法:将不同浓度克氏螯虾壳聚糖与大肠埃希菌及金黄色葡萄球菌作用3.5h,检测细菌上清液中草酰乙酸氨基转移酶活性、总蛋白及核酸含量;用透射电镜观察细菌与壳聚糖作用1h后的形态变化;将62.5mg/L壳聚糖与含十二烷基磺酸钠的菌液作用,观察溶菌效果。结果:克氏螯虾壳聚糖与细菌作用后上清液中草酰乙酸氨基转移酶活性、总蛋白和核酸含量显著高于对照组(p<0.01);透射电镜下发现两种细菌都有菌内物质泄漏及形态变化发生;62.5mg/L壳聚糖能增加十二烷基磺酸钠的溶菌作用(p<0.01)。结论:克氏螯虾壳聚糖能破坏细菌的表面结构,影响屏障功能,使菌内物质泄漏,并能协同SDS对细菌的溶菌作用。

Effect of chitosan from redswamp crayfish on bacterial cell surface was investigated. Escherichia coli （E.coli） and Staphylococcus aureus （S.aureus） were treated with chitosan solutions at varying concentrations for 3.5 h. The leakage of celluar content, the asparate transaminase （AST） activity, total protein （TP） content and nucleic acid content in the supernatants of bacterial suspension treated with the chitosan solutios were analyzed as well as morphological alterations of bacteria using transmission electron microscope （TEM）. Results indicated that AST activity and the contents of TP nuleotides in chitosan solutions were significant higher than those in control （p 〈 0.01）. TEM image indicated the cellular content leakage and morphological alterations of both bacteria treated with chitosan. Chitosan was also found to significantly enhance SDS-induced bacteriolysis （p 〈 0.01）. Our results suggested that chitosan from redswamp crayfish is able to damage the bacterial surface structure and lead to the loss of barrier function and the leakage of cellular content.