Morphological and physiological changes in Microcystis aeruginosa as a result of interactions with heterotrophic bacteria
Morphological and physiological changes in Microcystis aeruginosa as a result of interactions with heterotrophic bacteria
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DOI：
10.1111/j.1365-2427.2010.02551.x
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发表时间：
2011-06-01
影响因子：
2.7
通讯作者：
Yang, Xi
中科院分区：
文献类型：
--
作者：
Shen, Hong;Niu, Yuan;Yang, Xi
P>1。为了揭示水生异养细菌在自然水体微囊藻水华发育过程中的作用，我们将单细胞铜绿微囊藻与天然微囊藻相关异养细菌群落共培养。2．在异养细菌存在的情况下，不同初始细胞密度的单细胞铜绿微囊藻聚集成菌落，而无菌微囊藻则继续以单细胞形式生长。细胞聚集后，非无菌铜绿假单胞菌的比生长速率、叶绿素a含量、最大电子传递速率（ETRmax）和胞外多糖（EPS）的合成和分泌均高于无菌铜绿假单胞菌，而聚集前，无菌和非无菌铜绿假单胞菌表现出相同的生理特性。 3．通过 PCR 变性梯度凝胶电泳 (PCR-DGGE) 指纹分析异养细菌群落组成。共接种培养物中异养细菌的生物量大幅增加，但共接种培养物中的 DGGE 条带模式与仅含有异养细菌的对照培养物中的 DGGE 条带模式明显不同。 DGGE条带测序表明，卟啉杆菌、黄杆菌科和一种未培养的细菌可能是导致铜绿假单胞菌聚集的特殊细菌。4．非无菌铜绿假单胞菌中 EPS 的产生创造了微环境，可能有助于将蓝藻细胞及其相关细菌细胞连接成互利的菌落。微囊藻菌落形成有利于长期维持高生物量，铜绿微囊藻分泌EPS可促进异养菌生长。5．我们的研究结果表明，天然异养细菌群落在自然水域中微囊藻水华的发展中发挥着作用。细菌群落变化以及蓝藻与异养细菌之间相互作用背后的机制需要进一步研究。
P>1. To reveal the role of aquatic heterotrophic bacteria in the process of development of Microcystis blooms in natural waters, we cocultured unicellular Microcystis aeruginosa with a natural Microcystis-associated heterotrophic bacterial community.2. Unicellular M. aeruginosa at different initial cell densities aggregated into colonies in the presence of heterotrophic bacteria, while axenic Microcystis continued to grow as single cells. The specific growth rate, the chl a content, the maximum electron transport rate (ETRmax) and the synthesis and secretion of extracellular polysaccharide (EPS) were higher in non-axenic M. aeruginosa than in axenic M. aeruginosa after cell aggregation, whereas axenic and non-axenic M. aeruginosa displayed the same physiological characteristic before aggregation.3. Heterotrophic bacterial community composition was analysed by PCR-denaturing gradient gel electrophoresis (PCR-DGGE) fingerprinting. The biomass of heterotrophic bacteria strongly increased in the coinoculated cultures, but the DGGE banding patterns in coinoculated cultures were distinctly dissimilar to those in control cultures with only heterotrophic bacteria. Sequencing of DGGE bands suggested that Porphyrobacter, Flavobacteriaceae and one uncultured bacterium could be specialist bacteria responsible for the aggregation of M. aeruginosa.4. The production of EPS in non-axenic M. aeruginosa created microenvironments that probably served to link both cyanobacterial cells and their associated bacterial cells into mutually beneficial colonies. Microcystis colony formation facilitates the maintenance of high biomass for a long time, and the growth of heterotrophic bacteria was enhanced by EPS secretion from M. aeruginosa.5. The results from our study suggest that natural heterotrophic bacterial communities have a role in the development of Microcystis blooms in natural waters. The mechanisms behind the changes of the bacterial community and interaction between cyanobacteria and heterotrophic bacteria need further investigations.