Cyanobacteria are a group of oxygenic photosynthetic prokaryotes found in almost all habitats on earth including those characterized as extreme environments. It has been observed that the number of studies dealing with the biodiversity of extremophilic cyanobacteria is limited while studies exploring their bioactive potential are even scarcer. The taxonomy of three Nostoc-like cyanobacterial strains isolated from a shallow lake in Brazil was studied by applying a polyphasic approach. The bioactive potential of the strains was also evaluated using antimicrobial susceptibility testing. The metabolites present in the bioactive HPLC fractions were identified by UPLC/ESI/Q-TOF. Based on our phylogenetic inferences in combination with morphological and ecological information, we describe Aliinostoc alkaliphilum sp. nov., exhibiting antibacterial and antifungal activities. The main bioactive metabolite in all three strains was nocuolin A, which represents the first report of this metabolite in Aliinostoc. Our phylogenetic studies also revealed that many bioactive metabolite-producting strains that are currently assigned to Nostoc belong to other distinct evolutionary lineages. These findings highlight the importance of polyphasic approach studies in both cyanobacterial taxonomy and natural product discovery programs.

中文翻译：

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Aliinostoc 嗜碱菌的描述。十一月 (Nostocales, Cyanobacteria)，一种来自 Salina Verde (Pantanal, Brazil) 的新的生物活性代谢物生产菌株和发菜属和类似发菜属的生物活性代谢物的分类分布

蓝细菌是一组含氧光合原核生物，几乎遍布地球上的所有栖息地，包括那些以极端环境为特征的栖息地。据观察，关于极端蓝藻生物多样性的研究数量有限，而探索其生物活性潜力的研究则更少。通过应用多相方法研究了从巴西浅湖中分离出的三种类似念珠菌的蓝藻菌株的分类。还使用抗菌药敏试验评估了菌株的生物活性潜力。通过 UPLC/ESI/Q-TOF 鉴定生物活性 HPLC 级分中存在的代谢物。基于我们的系统发育推断并结合形态学和生态学信息，我们描述了Aliinostoc 嗜碱菌 sp。十一月，表现出抗菌和抗真菌活性。这三种菌株的主要生物活性代谢物是 nocuolin A，这是该代谢物在Aliinostoc中的首次报道。我们的系统发育研究还表明，目前分配给发菜属的许多产生生物活性代谢物的菌株属于其他不同的进化谱系。这些发现强调了多相方法研究在蓝藻分类学和天然产物发现计划中的重要性。