细菌生物膜是表面粘附的微生物群落,其中单个细胞被自身产生的多糖细胞外基质包围,细胞外DNA(eDNA)和蛋白质。生物膜内的基质组分之间的相互作用负责在生物膜发育期间产生适应性结构。然而,尚不清楚基质组分之间的相互作用如何有助于三维(3D)生物膜结构的构建。
DNaseI处理在生物膜发育的早期阶段显著抑制枯草芽孢杆菌生物膜的形成。共聚焦激光扫描显微镜(CLSM)和图像分析显示,在枯草芽孢杆菌生物膜发育的早期阶段,eDNA与胞外多糖(EPS)合作,而EPS在后期发挥了主要的结构性作用。此外,枯草芽孢杆菌SBE1中EPS产生基因epsG的缺失导致EPS与eDNA之间相互作用的丧失,并减少了空气-液体界面膜中生物膜的生物量。通过等温滴定量热法(ITC)证实了这两种必需的生物膜基质组分之间的物理相互作用。
生物膜3D结构通过周围的eDNA和EPS相互连接。在生物膜发育的早期阶段,eDNA与EPS相互作用,而EPS主要参与生物膜的成熟。这项研究的发现为eDNA和EPS之间的相互作用在塑造生物膜3D基质结构和生物膜形成中的作用提供了更好的理解。
Bacterial biofilms are surface-adherent microbial communities in which individual cells are surrounded by a self-produced extracellular matrix of polysaccharides, extracellular DNA (eDNA) and proteins. Interactions among matrix components within biofilms are responsible for creating an adaptable structure during biofilm development. However, it is unclear how the interactions among matrix components contribute to the construction of the three-dimensional (3D) biofilm architecture.
DNase I treatment significantly inhibited Bacillus subtilis biofilm formation in the early phases of biofilm development. Confocal laser scanning microscopy (CLSM) and image analysis revealed that eDNA was cooperative with exopolysaccharide (EPS) in the early stages of B. subtilis biofilm development, while EPS played a major structural role in the later stages. In addition, deletion of the EPS production gene epsG in B. subtilis SBE1 resulted in loss of the interaction between EPS and eDNA and reduced the biofilm biomass in pellicles at the air-liquid interface. The physical interaction between these two essential biofilm matrix components was confirmed by isothermal titration calorimetry (ITC).
Biofilm 3D structures become interconnected through surrounding eDNA and EPS. eDNA interacts with EPS in the early phases of biofilm development, while EPS mainly participates in the maturation of biofilms. The findings of this study provide a better understanding of the role of the interaction between eDNA and EPS in shaping the biofilm 3D matrix structure and biofilm formation.