Morphological, biochemical and molecular characterization of Anabaena, Aphanizomenon and Nostoc strains (Cyanobacteria, Nostocales) isolated from Portuguese freshwater habitats
Morphological, biochemical and molecular characterization of Anabaena, Aphanizomenon and Nostoc strains (Cyanobacteria, Nostocales) isolated from Portuguese freshwater habitats
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DOI：
10.1007/s10750-010-0572-5
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发表时间：
2011-03-01
期刊：
影响因子：
2.6
通讯作者：
Peixoto, Francisco
中科院分区：
文献类型：
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作者：
Galhano, Victor;de Figueiredo, Daniela R.;Peixoto, Francisco
蓝藻念珠藻科分类群的研究对全球科学界很重要，主要是因为属于念珠藻目的大量有益菌株固定大气氮，从而有助于全球农业土壤的肥力，而其他菌株则由于参与有毒水华事件而在水生生态系统中表现为滋扰微生物。然而，尽管它们的生态重要性和环境问题，它们的鉴定和分类仍然是有问题的和可疑的，往往是基于目前的形态和生理研究，产生混乱的分类系统，通常在不同的条件下变化。因此，本研究的目的是调查通过多相的方法在形态，生化和基因型特征的三个念珠藻科蓝藻菌株分离自葡萄牙中西部的浅淡水水体的差异。形态测量，遗传（16 S rRNA，nifH和hetR片段）和生化（脂肪酸甲酯; FAME配置文件）数据被用来表征菌株。经形态学分析和16 S rRNA序列测定，菌株分别属于柱孢鱼腥藻（UTAD_A212）、纤细束丝藻（UADFA 16）和蝇念珠藻（UTAD_N213）。这些菌株表现出明显的形态和遗传特征，易于分配到各自的属。同样的情况发生在使用hetR和nifH基因的部分序列，尽管缺乏存放的序列。生化特性表明，FAME的配置文件获得的形态和分子分析是一致的。单不饱和与多不饱和FAME的比值和不饱和指数可作为属特异性化学分类学生物标志物。
Studies of cyanobacterial nostocacean taxa are important to the global scientific community, mainly because a significant number of beneficial strains that belong to the order Nostocales fix atmospheric nitrogen, thus contributing to the fertility of agricultural soils worldwide, while others behave as nuisance microorganisms in aquatic ecosystems due to their involvement in toxic bloom events. However, in spite of their ecological importance and environmental concerns, their identification and taxonomy are still problematic and doubtful, often being based on current morphological and physiological studies, which generate confusing classification systems and usually vary under different conditions. Therefore, the present research aimed to investigate through a polyphasic approach differences in morphological, biochemical and genotypic features of three nostocacean cyanobacterial strains isolated from central-western Portuguese shallow freshwater bodies. Morphometric, genetic (16S rRNA, nifH and hetR fragments) and biochemical (fatty acid methyl ester; FAME profiles) data were used to characterize the strains. Morphological analysis and sequencing of 16S rRNA fragments showed that the strains belonged to Anabaena cylindrica (UTAD_A212), Aphanizomenon gracile (UADFA16) and Nostoc muscorum (UTAD_N213) species. These strains showed clear distinct morphological and genetic features, allowing easy allocation to their respective genera. The same happened by using partial sequences of hetR and nifH genes, in spite of the scarcity of deposited sequences. Biochemical characterization showed that the FAME profiles obtained were consistent with both morphological and molecular analyses. It was suggested that the ratio of monounsaturated to polyunsaturated FAMEs, together with the unsaturation index, could be used as genus-specific chemotaxonomic biomarkers.