Alvarado Pamela, Huang Ying, Wang Jian, Garrido Ignacio, Leiva Sergio
Universidad Tecnológica de Chile INACAP, Avenida René Soriano 2382, Osorno, Chile.
State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.
Antonie Van Leeuwenhoek. 2018 Sep;111(9):1543-1555. doi: 10.1007/s10482-018-1044-6. Epub 2018 Feb 19.
Marine macroalgae are emerging as an untapped source of novel microbial diversity and, therefore, of new bioactive secondary metabolites. This study was aimed at assessing the diversity and antimicrobial activity of the culturable Gram-positive bacteria associated with the surface of three co-occurring Antarctic macroalgae. Specimens of Adenocystis utricularis (brown alga), Iridaea cordata (red alga) and Monostroma hariotii (green alga) were collected from the intertidal zone of King George Island, Antarctica. Gram-positive bacteria were investigated by cultivation-based methods and 16S rRNA gene sequencing, and screened for antimicrobial activity against a panel of pathogenic microorganisms. Isolates were found to belong to 12 families, with a dominance of Microbacteriaceae and Micrococcaceae. Seventeen genera of Actinobacteria and 2 of Firmicutes were cultured from the three macroalgae, containing 29 phylotypes. Three phylotypes within Actinobacteria were regarded as potentially novel species. Sixteen isolates belonging to the genera Agrococcus, Arthrobacter, Micrococcus, Pseudarthrobacter, Pseudonocardia, Sanguibacter, Staphylococcus, Streptomyces and Tessaracoccus exhibited antibiotic activity against at least one of the indicator strains. The bacterial phylotype composition was distinct among the three macroalgae species, suggesting that these macroalgae host species-specific Gram-positive associates. The results highlight the importance of Antarctic macroalgae as a rich source of Gram-positive bacterial diversity and potentially novel species, and a reservoir of bacteria producing biologically active compounds with pharmacological potential.
海洋大型藻类正成为新的微生物多样性以及新的生物活性次生代谢产物的未开发来源。本研究旨在评估与三种共生南极大型藻类表面相关的可培养革兰氏阳性细菌的多样性和抗菌活性。从南极乔治王岛潮间带采集了泡状腺囊藻（褐藻）、心形艾氏藻（红藻）和哈氏单条藻（绿藻）的样本。通过基于培养的方法和16S rRNA基因测序对革兰氏阳性细菌进行了研究，并针对一组致病微生物筛选了抗菌活性。发现分离株属于12个科，其中微杆菌科和微球菌科占主导。从这三种大型藻类中培养出了17个放线菌属和2个厚壁菌属，包含29个系统发育型。放线菌中的三个系统发育型被认为可能是新物种。属于土壤球菌属、节杆菌属、微球菌属、假节杆菌属、假诺卡氏菌属、血杆菌属、葡萄球菌属、链霉菌属和四联球菌属的16个分离株对至少一种指示菌株表现出抗生素活性。这三种大型藻类物种的细菌系统发育型组成不同，表明这些大型藻类拥有物种特异性的革兰氏阳性共生菌。结果突出了南极大型藻类作为革兰氏阳性细菌多样性和潜在新物种的丰富来源以及产生具有药理学潜力的生物活性化合物的细菌库的重要性。
