Mohanty Bijayalaxmi, Majedi Seyed Mohammad, Pavagadhi Shruti, Te Shu Harn, Boo Chek Yin, Gin Karina Yew-Hoong, Swarup Sanjay
NUS Environmental Research Institute, National University of Singapore, Singapore 117411, Singapore.
Singapore Centre for Environmental Life Sciences Engineering, National University of Singapore, Singapore 117456, Singapore.
Metabolites. 2022 Apr 29;12(5):406. doi: 10.3390/metabo12050406.
Rapid proliferation of cyanobacteria in both benthic and suspended (planktonic) habitats is a major threat to environmental safety, as they produce nuisance compounds such as cytotoxins and off-flavors, which degrade the safety and quality of water supplies. Temperature and light irradiance are two of the key factors in regulating the occurrence of algal blooms and production of major off-flavors. However, the role of these factors in regulating the growth and metabolism is poorly explored for both benthic and planktonic cyanobacteria. To fill this gap, we studied the effects of light and temperature on the growth and metabolic profiling of both benthic ( sp. MRB220) and planktonic ( sp. SR001) environmental species collected from a freshwater reservoir in Singapore. Moreover, this study is the first report on the metabolic profiling of cyanobacteria belonging to two different habitats in response to altered environmental conditions. The highest growth rate of both species was observed at the highest light intensity (100 μmol photons/m²/s) and at a temperature of 33 °C. Systematic metabolite profiling analysis suggested that temperature had a more profound effect on metabolome of the , whereas light had a greater effect in the case of . Interestingly, sp. SR001 showed a specialized adaptation mechanism via biosynthesis of arginine, and metabolism of cysteine and methionine to survive and withstand higher temperatures of 38 °C and higher. Hence, the mode of strategies for coping with different light and temperature conditions was correlated with the growth and alteration in metabolic activities for physiological and ecological adaptations in both species. In addition, we putatively identified a number of unique metabolites with a broad range of antimicrobial activities in both species in response to both light and temperature. These metabolites could play a role in the dominant behavior of these species in suppressing competition during bloom formation. Overall, this study elucidated novel insights into the effects of environmental factors on the growth, metabolism, and adaptation strategies of cyanobacteria from two different habitats, and could be useful in controlling their harmful effects on human health and environmental concerns.
蓝藻在底栖和悬浮（浮游）生境中的快速增殖对环境安全构成重大威胁，因为它们会产生细胞毒素和异味等有害化合物，从而降低供水的安全性和质量。温度和光照强度是调节藻华发生和主要异味产生的两个关键因素。然而，对于底栖和浮游蓝藻，这些因素在调节其生长和代谢方面的作用尚未得到充分研究。为了填补这一空白，我们研究了光照和温度对从新加坡一个淡水水库采集的底栖（MRB220 种）和浮游（SR001 种）环境物种的生长和代谢谱的影响。此外，本研究是关于两种不同生境的蓝藻在环境条件改变时的代谢谱分析的首次报告。两种物种在最高光照强度（100 μmol 光子/m²/s）和 33°C 的温度下观察到最高生长速率。系统的代谢物谱分析表明，温度对[物种名称未明确处]的代谢组有更深远的影响，而光照对[物种名称未明确处]的影响更大。有趣的是，SR001 种通过精氨酸的生物合成以及半胱氨酸和蛋氨酸的代谢表现出一种特殊的适应机制，以在 38°C 及更高的温度下生存和耐受。因此，两种物种应对不同光照和温度条件的策略模式与生长以及代谢活动的改变相关，以实现生理和生态适应。此外，我们推测在两种物种中都鉴定出了许多具有广泛抗菌活性的独特代谢物，以响应光照和温度。这些代谢物可能在这些物种在藻华形成期间抑制竞争的主导行为中发挥作用。总体而言，本研究阐明了环境因素对来自两种不同生境的蓝藻的生长、代谢和适应策略的影响的新见解，并可能有助于控制它们对人类健康和环境问题的有害影响。
