IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal.
Syst Appl Microbiol. 2012 Mar;35(2):110-9. doi: 10.1016/j.syapm.2011.07.003. Epub 2012 Jan 25.
Cyanobacteria are important primary producers, and many are able to fix atmospheric nitrogen playing a key role in the marine environment. However, not much is known about the diversity of cyanobacteria in Portuguese marine waters. This paper describes the diversity of 60 strains isolated from benthic habitats in 9 sites (intertidal zones) on the Portuguese South and West coasts. The strains were characterized by a morphological study (light and electron microscopy) and by a molecular characterization (partial 16S rRNA, nifH, nifK, mcyA, mcyE/ndaF, sxtI genes). The morphological analyses revealed 35 morphotypes (15 genera and 16 species) belonging to 4 cyanobacterial Orders/Subsections. The dominant groups among the isolates were the Oscillatoriales. There is a broad congruence between morphological and molecular assignments. The 16S rRNA gene sequences of 9 strains have less than 97% similarity compared to the sequences in the databases, revealing novel cyanobacterial diversity. Phylogenetic analysis, based on partial 16S rRNA gene sequences showed at least 12 clusters. One-third of the isolates are potential N(2)-fixers, as they exhibit heterocysts or the presence of nif genes was demonstrated by PCR. Additionally, no conventional freshwater toxins genes were detected by PCR screening.
蓝细菌是重要的初级生产者，许多蓝细菌能够固定大气氮，在海洋环境中起着关键作用。然而，关于葡萄牙海洋水域蓝细菌的多样性，人们知之甚少。本文描述了从葡萄牙南、西海岸 9 个地点（潮间带）的底栖生境中分离出的 60 株蓝细菌的多样性。这些菌株通过形态学研究（光学和电子显微镜）和分子特征（部分 16S rRNA、nifH、nifK、mcyA、mcyE/ndaF、sxtI 基因）进行了鉴定。形态学分析显示，有 35 种形态型（15 属和 16 种），属于 4 个蓝细菌目/亚目。在分离株中占主导地位的是颤藻目。形态学和分子分类之间存在广泛的一致性。与数据库中的序列相比，9 株菌的 16S rRNA 基因序列相似度小于 97%，这揭示了新的蓝细菌多样性。基于部分 16S rRNA 基因序列的系统发育分析显示，至少有 12 个聚类。三分之一的分离株可能是固氮菌，因为它们表现出异形胞或通过 PCR 证明存在 nif 基因。此外，通过 PCR 筛选未检测到常规淡水毒素基因。
