Discerning biodegradation and adsorption of microcystin-LR in a shallow semi-enclosed bay and bacterial community shifts in response to associated process.
Discerning biodegradation and adsorption of microcystin-LR in a shallow semi-enclosed bay and bacterial community shifts in response to associated process.
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DOI：
10.1016/j.ecoenv.2016.05.033
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发表时间：
2016-10
影响因子：
6.8
通讯作者：
Jieming Li;Ji Li;G. Shi;Z. Mei;Ruiping Wang;D. Li
中科院分区：
文献类型：
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作者：
Jieming Li;Ji Li;G. Shi;Z. Mei;Ruiping Wang;D. Li
蓝藻产生的肝毒性微囊藻毒素（MCs）对水生生态系统和人类健康构成严重威胁，了解MCs的消除途径和机制，特别是在浅水和半封闭富营养区，具有重要意义。本研究成功识别了中国太湖梅梁湾北部水体和/或沉积物介导的微囊藻毒素lr （microcytin - lr， MCLR）的生物降解和吸附，并首次利用Illumina高通量测序（HTS）揭示了微生物群落组成对MCLR在沉积物中生物降解的响应。结果证实，与吸附相比，生物降解主要控制了研究区域的MCLR消除。湖水的生物降解速率为49.21 μg L−1d−1，对总体MCLR去除的贡献大于沉积物。沉积物在MCLR去除过程中也发挥了不可或缺的作用，主要是通过原生群落的生物降解（速率为17.27 μg L−1d−1）和二次吸附（<初始浓度的20%）。HTS分析显示，在沉积物介导的mclr生物降解过程中，土著群落组成发生变化，系统发育多样性降低。生物降解后的总组成中变形菌属占主导地位（39.34 ~ 86.78%），这主要是由于β-变形菌属的急剧增殖（22.76 ~ 74.80%），可能与沉积物中mclr的生物降解密切相关。此外，α-变形菌门、β-变形菌门和γ-变形菌门的几个属成员似乎是关键的降解者，因为它们在MCLR降解过程中占主导地位或种群数量增加。本研究拓展了对MCs自然淘汰机制的认识，对降低MCs的生物风险，保障水生生境生态系统安全具有指导意义。
Hepatotoxic microcystins (MCs) produced by cyanobacteria pose serious risks to aquatic ecosystems and human health, to understand elimination pathways and mechanisms for MCs, especially in a shallow and semi-enclosed eutrophic area, is of great significance. This study succeed in discerning biodegradation and adsorption of microcystin-LR (MCLR) mediated by water and/or sediment in northern part of Meiliang Bay in Lake Taihu, China, and among the first to reveal the shifts of indigenous bacterial community composition in response to MCLR-biodegradation in sediment by Illumina high-throughput sequencing (HTS). Results confirmed that biodegradation predominantly governed MCLR elimination as compared to adsorption in study area. Through faster biodegradation with a rate of 49.21 μg L−1d−1, lake water contributed more to overall MCLR removal than sediment. Sediment also played indispensable role in MCLR removal via primarily biodegradation by indigenous community (a rate of 17.27 μg L−1d−1) and secondarily adsorption (<20% of initial concentration). HTS analysis showed that indigenous community composition shifted with decreased phylogenetic diversity in response to sediment-mediated MCLR-biodegradation.Proteobacteriabecame predominant (39.34–86.78%) in overall composition after biodegradation, which was mostly contributed by sharp proliferation ofβ-proteobacteria(22.76–74.80%), and might closely link to MCLR-biodegradation in sediment. Moreover, the members of several genera belonging toα-proteobacteria,β-proteobacteriaandγ-proteobacteriaseemed to be key degraders because of their dominance or increasing population as MCLR degraded. This study expands understanding on natural elimination mechanism for MCs, and provides guidance to reduce MCs' biological risks and guarantee ecosystem safety in aquatic habitats.