2株中国红豆杉内生细菌代谢产抑菌活性物质的研究

Antibacterial Activities of Metabolites Produced by Two Endophytic Bacteria Isolates in Taxus Chinensis

自秦巴山区野生中国红豆杉(Taxus chinensis)中分离的25株内生细菌中筛选出2株具有较广抑菌活性的菌株TC-3和TC-2,通过生物学特征研究和16S rDNA序列分析,初步鉴定为Bacillus sp.和Bacillus subtilis。在排除酸性产物和过氧化氢的干扰后,TC-3和TC-2菌株发酵上清液对金黄色葡萄球菌(Staphyloccocus aureus)、枯草芽孢杆菌(Bacillus subtilis)等革兰氏阳性菌和大肠杆菌(Escherichia coli)等革兰氏阴性菌具有较好的抑菌作用,而且对部分真菌也有抑菌作用;经胰蛋白酶、胃蛋白酶和蛋白酶K处理后发酵液抑菌活性略有下降,表明该活性物质为非蛋白成分,或起抑菌作用的非单一物质。该活性物质不同于一般细菌素,属于类细菌素。它具有很好的热稳定性,在酸性条件下稳定且活性高,对蛋白酶敏感性低,且具有较广的抗菌谱。

In this study,two strains,TC-3 and TC-2,identified as Bacillus sp.and Bacillus subtilis based on the biological characteristics and 16S rDNA sequence analysis,was screened from 25 isolates of endophytic bacteria from wild Taxus chinensis in Qinba Mountain.Those strain exhibited the ability in producing inhibitory activity substance,Without the effect of organic acid and hydrogen peroxide,supernatant of the liquid culture of TC-3 and TC-2 showed significant inhibitory activity against gram-positive bacteria,including Staphylococcus aureus,Bacillus subtilis and gram-negative bacteria such as Escherichia coli.Inhibition of some kind of epiphyte was also found.After treatment with trypsin,pepsin and proteinase K,the culture＇s inhibitory activity decreased slightly,this showed that it is non-protein ingredients or antibacterial effect of the non-single material.This indicated it belongs to a kind of bacteriocin-like substance.The inhibitory substance,showed good heating stability,high activity at low pH,low sensitivity to proteinases and a broad antibacterial spectrum.