【摘要】 目的以南方红豆杉茎和叶为材料分离内生放线菌,并对分离菌株进行分类、抗菌活性和次级代谢产物合成相关基因开展研究。方法样品经严格的表面消毒,选用3种培养基分离南方红豆杉内生放线菌;分离菌株通过形态观察和16S RNA序列分析进行分类鉴定;使用琼脂移块法测试分离菌株的抗菌活性;通过PCR检测分离菌株的PKS-I/NRPS、卤化酶和P450酶基因。结果从3个样品中获得了6株内生放线菌,属于链霉菌属(Streptomyces)和小单孢菌属(Micromonospora)。部分分离菌株具有抗菌活性,其中1株对耐药金黄色葡萄球菌有拮抗活性,6株具有NRPS基因,2株具有PKS-I基因,1株具有P450酶基因和卤化酶基因。生物信息学分析表明,卤化酶和P450基因与Complestatin生物合成簇中相应基因有高达81%和95%一致性,暗示内生放线菌具有合成这种重要抗HIV活性化合物的潜力。结论南方红豆杉作为一种重要药用植物,其内生放线菌以链霉菌和小单孢菌为主,有很好的合成次级代谢产物的潜力,值得进一步深入研究。更多还原

【Abstract】 Objective To isolate entophytic actinomycetes from Taxus chinensis and investigate their antimicrobial activity and sec ondary metabolic potential of the isolates.Methods Samples were treated by a well-established surface-sterilized procedure,and plated on three selective media.The isolates were identified by morphology and 16S rRNA gene sequence analysis.Antimicrobial activity against Methicillin-resistant Staphylococcus aureus(MRSA) or Pseudomonas aeruginosa was tested using agar diffusion method.Secondary metabolites genes of PKSI/NRPS,halogenase and P450ase were detected by PCR amplification.Results 6 strains of endophytic actinomycetes were isolated from the stem and leaf of Taxus chinensis,collected in Chonqing.Antimicrobial assays showed that one strain displayed activity MRSA.Based on morphology and,5 isolates were identified as Streptomyces,the other one as Micromonospora.PCR screening of the secondary metabolites biosynthetic genes revealed that 6 strains harbor NRPS gene,2 strains possess PKS-1 and halogenase encoding gene(halo) and 1 strain contain oxyC gene.Sequencing and bioinformatics analysis showed that halo and oxyC genes displayed 81% and 95% identity to that for complestatin biosynthesis,respectively.Conclusion Taken together,the endophytic actinomycetes from Taxus chinensis could serve as a promising resource for novel bioactive compounds.更多还原