Bacterial dynamics in a microphytobenthic biofilm: A tidal mesocosm approach
Bacterial dynamics in a microphytobenthic biofilm: A tidal mesocosm approach
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DOI：
10.1016/j.seares.2014.03.003
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发表时间：
2014-09-01
影响因子：
2
通讯作者：
Dupuy, Christine
中科院分区：
文献类型：
--
作者：
Agogue, Helene;Mallet, Clarisse;Dupuy, Christine
在潮间泥滩，在低潮暴露，微型底栖植物（MPB）垂直迁移通过表面沉积物和形成，与异养细菌，一个短暂的生物膜。在这种生物膜内，MPB和细菌之间存在多种相互作用。这些微生物分泌广泛的胞外聚合物（EPS），这是生物膜基质的主要成分。在这项研究中，我们使用了潮汐围隔实验，以破译生物膜内的MPB-EPS-细菌复合物的相互作用。我们试图确定EPS是否可以根据生物膜的年龄和浸没/浮现期来控制细菌活性和/或生产和/或丰富度。MPB和原核生物的生物量动态、细菌生产、溶解有机碳（DOC）库中主要有机组分的水解（即，碳水化合物和多肽），并在8天内研究了细菌结构与不同EPS组分（碳水化合物和蛋白质：胶体和结合）动力学的关系。我们的实验强调了环境条件（光照，浸没/露出）对生物膜内相互作用的影响，以及对生物膜老化的影响。细菌的生产总是被EPS-碳水化合物所抑制，尤其是在低潮期。我们的研究结果表明，EPS的浓度和组成在细菌/MPB相互作用中起着重要作用：这些相互作用可以是积极的或消极的，以调节MPB和细菌的生产阶段。(C)© 2014 Elsevier B. V.保留所有权利。
In intertidal mudflats, during low tide exposure, microphytobenthos (MPB) migrate vertically through the surface sediment and form, with the heterotrophic bacteria, a transient biofilm. Inside this biofilm, multiple interactions exist between MPB and bacteria. These micro-organisms secrete a wide range of extracellular polymeric substances (EPS), which are major components of the biofilm matrix. In this study, we used a tidal mesocosm experiment in order to decipher the interactions of the MPB-EPS-bacteria complex within the biofilm. We tried to determine if the EPS could control bacterial activities and/or production and/or richness according to the age of the biofilm and to the immersion/emersion period. The dynamics of biomasses of MPB and prokaryotes, the bacterial production, the hydrolysis of predominating organic constituents in the dissolved organic carbon (DOC) pool (i.e., carbohydrates and polypeptides), and the bacterial structure were studied in relation to the different EPS fractions (carbohydrates and proteins: colloidal and bound) dynamics during 8 days. Our experiment had emphasized the influence of the environmental conditions (light, immersion/emersion) on the interactions within the biofilm and also on the effects on biofilm aging. Bacterial production was always inhibited by the bound EPS-carbohydrate, especially during low tide. Our results suggest that the concentration and composition of EPS had a major role in the bacterial/MPB interactions: these interactions can be either positive or negative in order to regulate the productive phases of MPB and bacteria. (C) 2014 Elsevier B.V. All rights reserved.