Paerl Hans W, Otten Timothy G, Joyner Alan R
Institute of Marine Sciences, University of North Carolina at Chapel Hill, Morehead City, NC, USA.
Bend Genetics, LLC, 87 Scripps Drive, Ste. 301, Sacramento, CA, USA.
Microb Biotechnol. 2016 Sep;9(5):641-51. doi: 10.1111/1751-7915.12383. Epub 2016 Jul 15.
The cyanobacteria are a phylum of bacteria that have played a key role in shaping the Earth's biosphere due to their pioneering ability to perform oxygenic photosynthesis. Throughout their history, cyanobacteria have experienced major biogeochemical changes accompanying Earth's geochemical evolution over the past 2.5+ billion years, including periods of extreme climatic change, hydrologic, nutrient and radiation stress. Today, they remain remarkably successful, exploiting human nutrient over-enrichment as nuisance "blooms." Cyanobacteria produce an array of unique metabolites, the functions and biotic ramifications of which are the subject of diverse ecophysiological studies. These metabolites are relevant from organismal and ecosystem function perspectives because some can be toxic and fatal to diverse biota, including zooplankton and fish consumers of algal biomass, and high-level consumers of aquatic food sources and drinking water, including humans. Given the long history of environmental extremes and selection pressures that cyanobacteria have experienced, it is likely that that these toxins serve ecophysiological functions aimed at optimizing growth and fitness during periods of environmental stress. Here, we explore the molecular and ecophysiological mechanisms underlying cyanotoxin production, with emphasis on key environmental conditions potentially controlling toxin production. Based on this information, we offer potential management strategies for reducing cyanotoxin potentials in natural waters; for cyanotoxins with no clear drivers yet elucidated, we highlight the data gaps and research questions that are still lacking. We focus on the four major classes of toxins (anatoxins, cylindrospermopsins, microcystins and saxitoxins) that have thus far been identified as relevant from environmental health perspectives, but caution there may be other harmful metabolites waiting to be elucidated.
蓝细菌是细菌的一个门类，由于其具有进行产氧光合作用的先驱能力，在塑造地球生物圈方面发挥了关键作用。在其整个历史进程中，蓝细菌经历了过去25亿多年来伴随地球地球化学演化的重大生物地球化学变化，包括极端气候变化、水文、营养和辐射压力时期。如今，它们仍然非常成功，利用人类营养物质的过度富集形成有害的“水华”。蓝细菌产生一系列独特的代谢产物，其功能和生物影响是各种生态生理学研究的主题。这些代谢产物从生物体和生态系统功能的角度来看是相关的，因为有些可能对各种生物群有毒甚至致命，包括浮游动物和以藻类生物量为食的鱼类，以及包括人类在内的水生食物源和饮用水的高级消费者。鉴于蓝细菌经历了长期的环境极端情况和选择压力，这些毒素很可能具有生态生理功能，旨在在环境压力时期优化生长和适应性。在这里，我们探讨蓝藻毒素产生的分子和生态生理机制，重点关注可能控制毒素产生的关键环境条件。基于这些信息，我们提供了降低天然水体中蓝藻毒素潜在风险的潜在管理策略；对于尚未明确驱动因素的蓝藻毒素，我们强调了仍然存在的数据差距和研究问题。我们关注迄今为止从环境卫生角度已确定相关的四大类毒素（类毒素、柱孢藻毒素、微囊藻毒素和石房蛤毒素），但提醒可能还有其他有害代谢产物有待阐明。
