The role of microcystins in maintaining colonies of bloom-forming Microcystis spp.
The role of microcystins in maintaining colonies of bloom-forming Microcystis spp.
复制标题
微囊藻毒素在维持水华形成微囊藻属菌落中的作用。
DOI：
10.1111/j.1462-2920.2011.02624.x
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发表时间：
2012-03-01
影响因子：
5.1
通讯作者：
Song, Lirong
中科院分区：
文献类型：
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作者：
Gan, Nanqin;Xiao, Yan;Song, Lirong
微囊藻是一个世界性的蓝藻属，并以许多不同的形式出现。蓝藻的大面积表面水华在整个地球仪的富营养化湖泊中是众所周知的。我们评估了微囊藻毒素（MC）在环境相关MC浓度（0.25-10 µg l（-1））下促进和维持水华形成细胞聚集体的作用。MCs显着增加微囊藻的菌落大小。微囊藻毒素-RR（MC-RR）处理的培养物（1 μg l（-1））中的菌落直径明显大于对照菌落，在微囊藻DC-M1，M中为1.5、2.6和2.7倍。微囊藻FACHB 1027。细胞外MC浓度的耗尽导致微囊藻菌落大小减少，表明释放的MC密切参与微囊藻菌落大小的维持。MC-RR暴露不影响微囊藻的生长速率，但显著增加胞外多糖（EPS）的产生。此外，MC-RR暴露似乎引发了四个多糖生物合成相关基因的某些部分的上调：capD，csaB，tagH和epsL。这些结果强烈表明，MC-RR诱导的多糖是MCs增强微囊藻菌落形成的主要机制。因此，细胞释放的MCs，可能发挥关键作用的持久性的藻类群体和微囊藻的优势。
Microcystis is a cosmopolitan genus of cyanobacteria and occurs in many different forms. Large surface blooms of the cyanobacterium are well known in eutrophic lakes throughout the globe. We evaluated the role of microcystins (MCs) in promoting and maintaining bloom-forming cell aggregates at environmentally relevant MC concentrations (0.25-10 µg l(-1)). MCs significantly enhanced Microcystis colony sizes. Colonial diameters in microcystin-RR (MC-RR)-treated cultures (at 1 µg l(-1)) were significantly larger than control colonies, by factors of 1.5, 2.6 and 2.7 in Microcystis wesenbergii DC-M1, M. ichthyoblabe TH-M1 and Microcystis sp. FACHB1027 respectively. Depletion of extracellular MC concentrations caused Microcystis colony size to decrease, suggesting that released MCs are intimately involved in the maintenance of Microcystis colonial size. MC-RR exposure did not influence Microcystis growth rate, but did significantly increase the production of extracellular polysaccharides (EPS). In addition, MC-RR exposure appeared to trigger upregulation of certain parts of four polysaccharide biosynthesis-related genes: capD, csaB, tagH and epsL. These results strongly indicate that induction of polysaccharides by MC-RR was the major mechanism through which MCs enhanced colony formation in Microcystis spp. Cellular release of MCs, therefore, may play a key role in the persistence of algal colonies and the dominance of Microcystis.