微囊藻强化假单胞菌产胞外超氧自由基及其机制  

Microcystis enhanced production of extracellular superoxide radicals by Pseudomonas and its mechanism

作　　者：倪蓉 王茜[2] 张长禄 吴佳萍 蔡文钊 李海燕 戚菁[2,3] 胡承志 NI Rong;WANG Xi;ZHANG Changlu;WU Jiaping;CAI Wenzhao;LI Haiyan;QI Jing;HU Chengzhi(School of Environmental and Energy Engineering,Beijing University of Civil Engineering and Architecture,Beijing 102616,China;Research Center for Eco-Environmental Sciences,Chinese Academy of Sciences,Beijing 100085,China;Jiangsu Collaborative Innovation Center for Water Treatment Technology and Materials,Suzhou University of Science and Technology,Suzhou 215009,China)

机构地区：[1]北京建筑大学,环境与能源工程学院,北京102616 [2]中国科学院生态环境研究中心,北京100085 [3]江苏水处理技术与材料协同创新中心,苏州科技大学,苏州215009

出　　处：《环境工程学报》2024年第8期2229-2236,共8页Chinese Journal of Environmental Engineering

基　　金：国家自然科学基金资助项目(52170014,52388101)。

摘　　要：生物源超氧自由基是天然水体中活性氧的重要来源,以天然水体中广泛存在的微囊藻和假单胞菌为研究对象,考察种间电子传递对天然水体中生物源超氧自由基生成的影响及机制。研究发现在天然水体中藻的存在可显著提升假单胞菌产生胞外超氧自由基的生成量,且这种上升趋势伴随着光照节律而变化,但该现象并非由菌藻密度及水体本底物质变化引起,而是由于细菌与藻类之间物质交换造成的。此外,随着培养时间的延长,胞外超氧自由基的产生量上升导致细菌密度降低,这是由于超氧自由基的大量生成造成细菌外部氧化压力急剧上升,使得细菌出现表面皱缩,进入衰亡阶段。为进一步探究微囊藻强化假单胞菌产生胞外超氧自由基的机制,对与超氧自由基生成直接相关的还原性辅酶I(NADH)和还原性辅酶II(NADPH)进行分析,发现在菌藻共存体系中NAD(P)H含量在胞外超氧自由基上升阶段显著上升,说明藻类通过光合作用产生的NAD(P)H可外泌到胞外进而影响细菌的电子传递,导致超氧自由基的产生。此外,NAD(P)H的增加还会影响细菌的抗氧化系统,降低细菌对超氧自由基的清除能力,从而导致超氧自由基在细菌体外的积累。这一发现揭示了一种新的菌藻互作机制,对理解环境微生态平衡和污染物降解具有重要意义。The production of biogenic superoxide radical,a critical group of reactive oxygen species in natural waters,was explored in this study by examining interspecies electron transfer involving M.aeruginosa and Pseudomonas,both prevalent in aquatic environments.The results showed that algal presence significantly augmented the generation of extracellular superoxide radical by Pseudomonas,a process notably influenced by diurnal light cycles.Crucially,this enhancement was not attributable to variations in microbial densities or background constituents of the water bodies;rather,it stemmed from substance exchanges between the bacteria and algae.Furthermore,as the incubation period extended,an increase in extracellular superoxide radical production was correlated with a reduction in bacterial density.This trend was likely due to elevated external oxidative stress from the abundant superoxide radicals,leading to morphological changes such as surface crumpling and subsequent cellular decay in the bacteria.To elucidate the mechanisms behind the enhanced generation of superoxide radicals by M.aeruginosa-stimulated Pseudomonas,the roles of reducing coenzymes I(NADH)and II(NADPH)were analyzed,which were intimately linked to the generation of these radicals.This finding revealed a significant uptick in NAD(P)H levels within the bacterial-algal coexistence system concurrent with the increase in superoxide radical production.This suggested that NAD(P)H generated by the algae via photosynthesis can be exocytosed into the extracellular environment,thereby influencing bacterial electron transfer and facilitating superoxide radical production.Additionally,the elevation in NAD(P)H levels also appeared to impair the bacterial antioxidant system,diminishing the bacterial capacity to scavenge superoxide radicals,thus fostering their accumulation.These insights unveiled a novel aspect of bacterial-algal interactions and were pivotal for comprehending the microecological dynamics in natural waters,with implications for environmental polluta

关 键 词：菌藻共存体系 胞外超氧自由基 铜绿微囊藻 假单胞菌 

分 类 号：X172[环境科学与工程—环境科学]