广谱抑菌作用的植物乳杆菌素LPC718特性的研究

Characteristics of plantaricin LPC718 with a board inhibitory spectrum

为了探明植物乳杆菌（Lactobacillus plantarum）LPC718所产细菌素plantaricin LPC718的特性,采用双层平板法测定了细菌素对酸、热和蛋白酶的敏感性、抑菌谱和作用方式;并采用硫酸铵沉淀和Sephadex G-25凝胶层析方法对活性物质进行了初步的纯化。研究表明plantaricin LPC718在p H3~5.5范围内具有抑菌活性;经100℃处理30 min后抑菌活力仍保持在80%以上;蛋白酶K、蛋白酶E和脂肪酶可完全破坏其抑菌活性,木瓜蛋白酶和糜蛋白酶可部分破坏其活力,而胃蛋白酶完全没有作用。plantaricin LPC718不仅对多种革兰氏阳性菌有较强的抑菌作用,更为重要的是对一些革兰氏阴性菌也有较强的抑菌作用。添加plantaricin LPC718可使鸡白痢沙门氏菌培养液中活菌数下降,但细胞密度基本维持不变。因而,plantaricin LPC718是一种新的具有广谱抑菌功能的、含脂类成分的细菌素,在酸和热条件下活性稳定,具有杀菌作用但不引起细胞裂解。

To determine the characteristics of plantaricin LPC718 produced by Lactobacillus plantarum LPC718, we used the agar well diffusion assay to investigate its sensitivity to pH, temperature and enzyme activity and its antibicrobial spectrum and action mode on Salmonella pullorum. Plantaricin LPC718 was purified using 60% saturation （NH4）2SO4 and Sephadex G25 column chromatography. The results showed that plantaricin LPC718 exhibited antibicrobial active in the pH range of 3 -5.5 and it activity was still kept more than 80% after treated at 100~C for 30 min. Its activity was completely inhibited by protease E, protease K and lipase and par- tially inhibited by papainase and chymotrypsin, while the activity could not be inhibited by pepsin. Plantaricin LPC718 showed the inhibitory effect on both gram positive and negative bacteria. The number of viable cells decreased but the density of cells did not change when plantaricin LPC718 was added into the culture of S. pullorum Together, our results revealed that plantaricin LPC718 is a lipoprotein, a novel bacteriocin with a broad inhibitory spectrum. Its activity was stable under the acid and heat condition. Plantaricin LPC718 showed antibicrobial function without lyzing cells.