产抗菌肽肠球菌的筛选及其抗菌肽生物学性质

利用牛津杯琼脂扩散法从新生儿粪便中筛选到一株产广谱抗菌肽的乳酸菌菌株,经菌体形态观察、生理生化分析、全自动微生物基因指纹鉴定系统和16S r DNA序列分析确定该菌株为屎肠球菌（Enterococcus faecium）。经过氧化氢酶处理后,发酵上清液仍具有抑菌活性,而胃蛋白酶、胰蛋白酶和蛋白酶K处理后,抑菌活性基本消失,说明该抑菌物质为蛋白类似物,即抗菌肽。该菌株所产抗菌肽在p H2.0⁵.0范围内保持活性,45¹00℃处理1 h后抑菌活性基本不变。发酵液中的抗菌肽经液相色谱-质谱联用（LC-MS/MS）和数据库APD比对得出3条不同的抗菌肽氨基序列,具有重要的研究价值。 

Screening of antimicrobial peptide- producing Enterococcus and its antibacterial peptide biological features

A antimicrobial peptides- producing lactic acid bacterial strain with broad- spectrum was selected from newborn by the oxford cup agar diffusion method. Based on cell morphological,physiological,biochemical characteristics,Ribo Printer and 16 S r DNA sequence analysis,the strain was identified as Enterococcus faecium.The antimicrobial activity of the fermented supernatant remained by catalase treatment. In addition,the inhibitory activity was lost after treated with trypsin,pepsin and proteinase K. Therefore,the inhibitory substance was preliminary determined as antimicrobial peptide.The antibacterial activity of antimicrobial peptide was not affected by low p H( 2.0~5.0) and the antimicrobial peptide exhibited good thermal stability by treatment from 45 ℃ to 100 ℃for 1 hour. Three amino acid sequences of the antimicrobial peptide were identified by LC- MS / MS and APD database.The antibacterial peptide has great research value.