Marine macroscopic colony-forming filamentous (MMCFF) cyanobacteria are considered as prolific producers of bioactive compounds. Thus, knowledge of the diversity of MMCFF cyanobacteria as related to bioactive compound production has become very important. However, basic taxonomic studies of MMCFF cyanobacteria are lacking. Many cyanobacterial taxa are still misidentified or undescribed. In this study, a total of 32 cyanobacterial colonies from nine coastal regions of Okinawa Prefecture were investigated for a diversity assessment. A polyphasic approach including morphological and molecular studies based on 16S rRNA gene sequences was performed to characterize Okinawan MMCFF cyanobacteria. Both morphological and molecular phylogenetic results showed that MMCFF cyanobacteria from Okinawan coasts are very diverse. We found morphotypes of Lyngbya-like, Phormidium-like, and Leptolyngbya-like groups among Okinawan cyanobacterial samples. Genetically, samples were distributed in various clades in the phylogenetic tree, including within Moorena, Okeania, Caldora, Neolyngbya, Dapis, as well as several unknown clades. In addition, cytotoxic activities of three samples from Kiyan coast were tested against HeLa cells. All three crude extracts of these samples showed strong cytotoxic activity with IC₅₀ < 1 μg/ml.

海洋宏观菌落形成丝状（MMCFF）蓝细菌被认为是生物活性化合物的多产者。因此，关于与生物活性化合物生产有关的MMCFF蓝细菌多样性的知识变得非常重要。但是，缺乏MMCFF蓝细菌的基本分类学研究。许多蓝细菌类群仍被误认或未描述。在这项研究中，共调查了来自冲绳县9个沿海地区的32个蓝细菌菌落，以进行多样性评估。进行了包括基于16S rRNA基因序列的形态学和分子研究在内的多相方法来表征冲绳MMCFF蓝细菌。形态学和分子系统发育结果均显示，来自冲绳海岸的MMCFF蓝细菌非常多样化。我们发现了冲绳蓝藻样本中的Lyngbya类，Phormidium类和Leptolyngbya类基团。从基因上讲，样本分布在系统发育树的各个进化枝中，包括Moorena，Okeania，Caldora，Neolyngbya，Dapis以及几个未知进化枝。此外，测试了来自Kiyan海岸的三个样品对HeLa细胞的细胞毒活性。这些样品的所有三种粗提取物均显示出强大的细胞毒性活性，IC ₅₀  <1μg/ ml。