CIIMAR/CIMAR, Interdisciplinary Centre of Marine and Environmental Research, University of Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos s/n, 4050-208, Porto, Portugal.
Department of Biology, Faculty of Sciences, University of Porto, Rua do Campo Alegre, 4169-007, Porto, Portugal.
Environ Sci Pollut Res Int. 2021 Jun;28(24):31731-31745. doi: 10.1007/s11356-021-12662-x. Epub 2021 Feb 20.
Cyanobacteria are a group of microorganisms that can be found in a diverse range of biogeographical areas and produce potent and damaging cyanotoxins, which reveal importance for continuous studies and surveillance efforts. In this study, we analyzed worldwide two-month culture-enriched water samples collected from 12 distinct countries (Costa Rica, Cuba, Fiji, France, Indonesia, Mali, Portugal, South Africa, Spain, Thailand, USA, Vietnam) including two undisclosed areas (Fiji and Mali). We performed a PCR-based molecular multi-step scheme that consisted in the detection of the main cyanobacterial species, genera, and cyanotoxins biosynthesis genes. Results from this study indicate that Microcystis aeruginosa followed by Planktothrix agardhii were the most prevalent species of all the 12 countries analyzed. Cylindrospermospis raciborskii was detected in Costa Rica, while P. agardhii was detected in Fiji and South Africa. M. aeruginosa was detected in Fiji and Mali. Regarding the main cyanotoxins biosynthesis genes, a cyrC gene fragment (cylindrospermopsins) was amplified in the African continent (South Africa), while anaC (anatoxin-a) was detected in two distinct locations, Mali and Vietnam. Saxitoxins biosynthesis gene was also detected in Fiji and Vietnam. Microcystins biosynthesis gene (mcyA) was co-detected with anatoxin-a biosynthesis gene in Mali and with saxitoxins biosynthesis gene (sxtI) in Portugal. This study therefore constitutes a major contribution to the global biogeography of cyanobacteria and its cyanotoxins and recommends continuous vigilance of toxic cyanobacteria particularly in the more undisclosed areas of the world. The PCR analysis data obtained in our 2-month culture-enriched water samples supports molecular methods as a preliminary tool in the environmental surveillance of cyanobacteria and cyanotoxins in undisclosed locations, particularly since the several positive amplifications detected may indicate that though samples were collected under non-bloom conditions, if environmental conditions change in the ecosystem, there is a risk that bloom-forming species may arose along with their detected cyanotoxicity.
蓝藻是一组微生物，可以在多种生物地理区域中找到，并产生强效且有害的蓝藻毒素，这表明需要不断进行研究和监测工作。在这项研究中，我们分析了来自 12 个不同国家（哥斯达黎加、古巴、斐济、法国、印度尼西亚、马里、葡萄牙、南非、西班牙、泰国、美国、越南）和两个未公开地区（斐济和马里）的为期两个月的富营养化水培养样本。我们进行了基于 PCR 的分子多步方案，该方案包括检测主要蓝藻物种、属和蓝藻毒素生物合成基因。这项研究的结果表明，在所有分析的 12 个国家中，最常见的物种是铜绿微囊藻和束丝藻。集胞藻在哥斯达黎加被检测到，而束丝藻在斐济和南非被检测到。铜绿微囊藻在斐济和马里被检测到。关于主要蓝藻毒素生物合成基因，一个 cyrC 基因片段（柱孢藻毒素）在非洲大陆（南非）被扩增，而 anaC（anatoxin-a）在两个不同的地点，马里和越南被检测到。在斐济和越南也检测到了石房蛤毒素生物合成基因。在斐济和越南也检测到了微囊藻毒素生物合成基因（mcyA）与anatoxin-a 生物合成基因共检测到，在马里与 saxitoxins 生物合成基因（sxtI）在葡萄牙共检测到。因此，这项研究是对蓝藻及其蓝藻毒素全球生物地理学的重大贡献，并建议对有毒蓝藻特别是世界上更不公开的地区保持持续警惕。我们在为期两个月的富营养化水样本中获得的 PCR 分析数据支持分子方法作为未公开地区蓝藻和蓝藻毒素环境监测的初步工具，特别是因为检测到的多个阳性扩增可能表明，尽管在非水华条件下采集了样本，但如果生态系统中的环境条件发生变化，那么形成水华的物种可能会随着其检测到的毒性而出现。
