Yang Cuiyun, Song Guojuan, Son Jiyoung, Howard Logan, Yu Xiao-Ying
Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA.
Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China.
Microorganisms. 2023 Jul 20;11(7):1841. doi: 10.3390/microorganisms11071841.
Diatoms contribute to carbon fixation in the oceans by photosynthesis and always form biofouling organized by extracellular polymeric substances (EPS) in the marine environment. Bacteria-produced quorum-sensing signal molecules N-acyl homoserine lactones (AHLs) were found to play an important role in the development of sp. in previous studies, but the EPS composition change was unclear. This study used the technology of alcian blue staining and scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and time-of-flight secondary ion mass spectrometry (ToF-SIMS) to directly observe the biofilm formation process. The results showed that AHLs promote the growth rates of diatoms and the EPS secretion of biofilm components. AHLs facilitated the diatom-biofilm formation by a forming process dependent on the length of carbon chains. AHLs increased the biofilm thickness and the fluorescence intensity and then altered the three-dimensional (3D) structures of the diatom-biofilm. In addition, the enhanced EPS content in the diatom-biofilm testified that AHLs aided biofilm formation. This study provides a collection of new experimental evidence of the interaction between bacteria and microalgae in fouling biofilms.
硅藻通过光合作用促进海洋中的碳固定，并且在海洋环境中总是形成由胞外聚合物（EPS）组织的生物污垢。在先前的研究中发现，细菌产生的群体感应信号分子N-酰基高丝氨酸内酯（AHLs）在 sp. 的发育中起重要作用，但EPS组成的变化尚不清楚。本研究使用阿尔新蓝染色技术以及扫描电子显微镜（SEM）、共聚焦激光扫描显微镜（CLSM）和飞行时间二次离子质谱（ToF-SIMS）直接观察生物膜的形成过程。结果表明，AHLs促进了硅藻的生长速率以及生物膜成分的EPS分泌。AHLs通过依赖于碳链长度的形成过程促进硅藻生物膜的形成。AHLs增加了生物膜厚度和荧光强度，进而改变了硅藻生物膜的三维（3D）结构。此外，硅藻生物膜中EPS含量的增加证明AHLs有助于生物膜的形成。本研究提供了关于污垢生物膜中细菌与微藻之间相互作用的新实验证据。
