Rojas Jose Luis, Martín Jesús, Tormo José Rubén, Vicente Francisca, Brunati Mara, Ciciliato Ismaela, Losi Daniele, Van Trappen Stefanie, Mergaert Joris, Swings Jean, Marinelli Flavia, Genilloud Olga
CIBE, Merck Research Laboratories, Merck Sharp and Dohme de España S.A., Josefa Valcárcel 38, E-28027 Madrid, Spain.
Mar Genomics. 2009 Mar;2(1):33-41. doi: 10.1016/j.margen.2009.03.005. Epub 2009 Apr 8.
During the MICROMAT project, the bacterial diversity of microbial mats growing in the benthic environment of Antarctic lakes was accessed for the discovery of novel antibiotics. In all, 723 Antarctic heterotrophic bacteria belonging to novel and/or endemic taxa in the α-, β- and γ-subclasses of the Proteobacteria, the Bacteroidetes branch, and of the high and low percentage G+C Gram-positives, were isolated, cultivated in different media and at different temperatures, and then screened for the production of antimicrobial activities. A total of 6348 extracts were prepared by solid phase extraction of the culture broths or by biomass solvent extraction. 122 bacteria showed antibacterial activity against the Gram-positives Staphylococcus aureus and to a lower extent Enterococcus faecium, and versus the Gram-negative Escherichia coli. Few of these strains showed also some antifungal activity against Cryptococcus neoformans, Aspergillus fumigatus and to a lower extent Candida albicans. LC-MS fractionation of extracts from a subset of strains (hits) that exhibited relatively potent antibacterial activities evidenced a chemical novelty that was further investigated. Two strains of Arthrobacter agilis produced potent antibacterial compounds with activity against Gram-positives and possibly related to novel cyclic thiazolyl peptides. To our knowledge, this is the first report of new antibiotics produced by bacteria from benthic microbial mats from Antarctic lakes. With no doubts these microbial assemblages represent an extremely rich source for the isolation of new strains producing novel bioactive metabolites with the potential to be developed as antibiotic compounds.
在“微量材料”项目中，为发现新型抗生素，对南极湖泊底栖环境中生长的微生物垫的细菌多样性进行了研究。总共分离出723株南极异养细菌，它们属于变形菌门α-、β-和γ-亚类、拟杆菌门分支以及高G+C和低G+C革兰氏阳性菌中的新分类群和/或特有分类群，在不同培养基和不同温度下进行培养，然后筛选其抗菌活性的产生情况。通过对培养液进行固相萃取或对生物量进行溶剂萃取，共制备了6348份提取物。122株细菌对革兰氏阳性菌金黄色葡萄球菌以及程度稍低的粪肠球菌和革兰氏阴性菌大肠杆菌表现出抗菌活性。其中少数菌株对新型隐球菌、烟曲霉以及程度稍低的白色念珠菌也表现出一些抗真菌活性。对表现出相对较强抗菌活性的一部分菌株（阳性结果）的提取物进行液相色谱-质谱分级分离，证明了其化学新颖性，并对此进行了进一步研究。两株敏捷节杆菌产生了具有抗革兰氏阳性菌活性的强效抗菌化合物，可能与新型环状噻唑基肽有关。据我们所知，这是关于南极湖泊底栖微生物垫细菌产生新抗生素的首次报道。毫无疑问，这些微生物群落是分离产生具有开发成抗生素化合物潜力的新型生物活性代谢物的新菌株的极其丰富的来源。
