长双歧杆菌细胞壁完整肽聚糖分离鉴定的研究

长双歧杆菌NQ-1501菌株,经三级扩大培养,离心集菌,用三氯乙酸处理以除去细胞壁上的磷壁酸及菌体内的核酸,经甲醇、丙酮脱脂,再经胰蛋白酶及中性蛋白酶进行复合酶解去除菌体内部的蛋白质,离心清洗、冻干即可制得肽聚糖。经过溶菌酶溶解试验,紫外可见光谱扫描分析证明所得产物为肽聚糖,化学组分分析显示其主要由多肽与氨基己糖组成,透射电镜观察显示所提取的肽聚糖仍保持着原有的细菌细胞形态。证明所提取的肽聚糖为完整肽聚糖。

Studies on the Isolation and Identification of Whole Peptidoglycan from Bifidobacterium longum

The cell wall WPG of Bifidobacterium longum NQ-1501 was extracted and purified as follows:(1) collecting bacteria by Centrifuge After three-level culture expansion . (2)Treating the bacteria cells with trichloroacetic acid in order to remove the wall teichoic acids as well as nucleic acid.(3)Delipoiding the residue with methanol and acetone.(4)Digesting the defatted residue with trypsin and neutral protease.(5) Cleaned by centrifugation and lyoghilized.It has been proved by lysozyme and UV-visible absorption spectra that the extracts were peptidoglycan. The results of chemical analysis indicated that WPG was mainly composed of polypeptides and amino hexose. The transmission electeonmicroscopic observation of WPG showed that WPG held the physically intact cell wall structure of the whole cells. In conclusion the peptidoglycan we obtained was whole peptidoglycan.