1株罗汉杉内生放线菌的鉴定、活性分析及抗生素生物合成基因的筛查

对1株从罗汉杉分离的内生放线菌LCB-0297进行系统学鉴定,在ISP3培养基上其气生菌丝灰烬色,有粉褐色可溶性色素,电镜观察孢子丝呈螺旋状,孢子椭球形表面多刺,通过其形态、生理生化特征初步确定为链霉菌。16S rRNA基因序列分析显示,放线菌LCB-0297与Streptomyces lanatus NBRC 12787（T）最为相似,相似性为98.531%,但在N-J树上仍在较远的2个分支上,确定为Streptomyces sp.。通过滤纸片法、SRB法进行抑菌、细胞毒活性检测,显示出较强的抑菌及抗癌活性。用PCR的方法对其多种抗生素生物合成基因进行筛查,该菌株含有Ⅰ型聚酮合成酶（PKS-Ⅰ）、非核糖体多肽合成酶（NRPS）、Ⅱ型聚酮合成酶（PKS-Ⅱ）的基因,含有多种潜在的抗生素合成基因。

Identification, Activity Analysis and Antibiotics Biosynthesis Genes Check-Screening of an Endophytic Actinomyces from Yew Podocarpus ( Podocarpus macrophyllus)

An endophytic actinomycetes strain LCB-0297 from Yew podocarpus(Podocarpus macrophyllus) was identified systematically.It produced ashy gray aerial mycelium and pinkish brown soluble pigment on ISP3 agar.Microscopic observation revealed it produced spiral chain of ellipsoidal spinous spores.It was primarily identified as a genus of Streptomyces according to its morphological,physiological and biochemical characteristics.Its 16S rRNA gene sequence shared the highest similarity(98.531%) with that of Streptomyces lanatus NBRC 12787(T),but they were still relatively far in two branches in the N-J tree,and confirmed as a Streptomyces sp..It demonstrated strong antimicrobial and anticancer activities by filter paper method,SRB bacteriostasis,and cytotoxic activity assays.PCR check-screening of its antibiotics biosynthesis genes revealed that it possessed polyketides synthetase I(PKS-I),polyketides synthetase II(PKS-II),non-ribosome polypeptide synthetase(NRPS) genes simultaneously,and contained multiple potential antibiotics biosynthesis genes.