米尔伊丽莎白拮抗菌的分离及抑菌作用研究

Study on isolation and antibacterial activity of antagonistic bacteria to Elizabethkingia miricola

试验旨在丰富米尔伊丽莎白菌(Elizabethkingia miricola,EMI)的防治方法,筛选对伊丽莎白菌具有拮抗作用的菌株。采用稀释涂布法对蚓粪中的EMI拮抗菌进行分离,通过形态学观察、生理生化特征分析、16S rRNA基因序列分析确定了分离菌株LM-7的分类地位;研究拮抗菌株LM-7对EMI的最佳抑菌条件及其抑菌活性物质。结果显示,LM-7为抗生链霉菌(Streptomyces antibioticus),在PDA培养基上对EMI的抑菌效果最佳,圈径比为11.13。LM-7胞内含有聚酮合酶基因PKS-Ⅰ、PKS-Ⅱ和非核糖体多肽合成酶基因(NRPS),抑菌活性成分与非核糖体多肽和聚酮类次级代谢产物有关,其抑菌活性物质主要存在于细胞的胞外分泌物中。研究表明,LM-7菌株可作为防治EMI的备选菌株,其发酵液具有开发为新颖结构活性化合物的潜力。

The study was to enrich the control measures of Elizabethkingia miricola EMI and screen the strains with antagonistic effect on Elizabethkingia.The EMI antagonism was isolated by dilution coating method.Morphological observation,physiological and biochemical characteristics analysis and 16S rRNA gene sequence analysis were used to determine the classification status of the isolated strain LM-7.To study the optimal bacteriostatic conditions and active substances of antagonistic strain LM-7 against EMI.The results showed that LM-7 belonged to Streptomyces antibioticus which had the best antibacterial effect on EMI in PDA medium,the ratio of circle and diameter was 11.13.LM-7 contained polyketide synthase genes PKS-I and PKS-II and non-ribosomal peptide synthase genes NRPS,the antibacterial active components were related to non-ribosomal peptides and polyketide secondary metabolites,and its antibacterial activity mainly existed in the exocytic secretion of cells.The study indicates that strain LM-7 can be used as a candidate strain for EMI control,and its fermentation broth has the potential to study and develop novel structurally activecompounds.