PDF(Pubmed)
Abstract：
Lactiplantibacillus plantarum is a Gram-positive non-motile bacterium capable of producing biofilms that contribute to the colonization of surfaces in a range of different environments. In this study, we compared two strains, WCFS1 and CIP104448, in their ability to produce biofilms in static and dynamic (flow) environments using an in-house designed flow setup. This flow setup enables us to impose a non-uniform flow velocity profile across the well. Biofilm formation occurred at the bottom of the well for both strains, under static and flow conditions, where in the latter condition, CIP104448 also showed increased biofilm formation at the walls of the well in line with the higher hydrophobicity of the cells and the increased initial attachment efficacy compared to WCFS1. Fluorescence and scanning electron microscopy showed open 3D structured biofilms formed under flow conditions, containing live cells and ∼30 % damaged/dead cells for CIP104448, whereas the WCFS1 biofilm showed live cells closely packed together. Comparative proteome analysis revealed minimal changes between planktonic and static biofilm cells of the respective strains suggesting that biofilm formation within 24 h is merely a passive process. Notably, observed proteome changes in WCFS1 and CIP104448 flow biofilm cells indicated similar and unique responses including changes in metabolic activity, redox/electron transfer and cell division proteins for both strains, and myo-inositol production for WCFS1 and oxidative stress response and DNA damage repair for CIP104448 uniquely. Exposure to DNase and protease treatments as well as lethal concentrations of peracetic acid showed highest resistance of flow biofilms. For the latter, CIP104448 flow biofilm even maintained its high disinfectant resistance after dispersal from the bottom and from the walls of the well. Combining all results highlights that L. plantarum biofilm structure and matrix, and physiological state and stress resistance of cells is strain dependent and strongly affected under flow conditions. It is concluded that consideration of effects of flow on biofilm formation is essential to better understand biofilm formation in different settings, including food processing environments.
摘要：
植物乳杆菌是一种革兰氏阳性非运动性细菌，能够产生生物膜，这些生物膜有助于在一系列不同环境中的表面定殖。在这项研究中,我们比较了两个菌株，WCFS1和CIP104448，在静态和动态（流动）环境中使用内部设计的流动设置产生生物膜的能力。这种流动设置使我们能够在整个井中施加不均匀的流速剖面。两种菌株的生物膜形成都发生在井底，在静态和流动条件下，在后一种情况下，与WCFS1相比,CIP104448还显示出在孔壁处增加的生物膜形成,与细胞的较高疏水性和增加的初始附着功效一致。荧光和扫描电子显微镜显示在流动条件下形成的开放式3D结构生物膜，含有活细胞和~30%受损/死亡细胞的CIP104448，而WCFS1生物膜显示活细胞紧密堆积在一起。比较蛋白质组分析显示，各个菌株的浮游和静态生物膜细胞之间的变化很小，这表明24小时内生物膜的形成只是一个被动过程。值得注意的是,在WCFS1和CIP104448流动生物膜细胞中观察到的蛋白质组变化表明相似和独特的反应，包括代谢活性的变化，两种菌株的氧化还原/电子转移和细胞分裂蛋白，和WCFS1的肌醇生产以及CIP104448独特的氧化应激反应和DNA损伤修复。暴露于DNase和蛋白酶处理以及致死浓度的过乙酸显示出最高的流动生物膜阻力。对于后者,CIP104448流动生物膜在从井底和井壁分散后甚至保持其高消毒剂抗性。综合所有结果，植物乳杆菌生物膜结构和基质，细胞的生理状态和应激抗性是应变依赖性的，并且在流动条件下受到强烈影响。结论是，考虑流动对生物膜形成的影响对于更好地了解不同环境中的生物膜形成至关重要。包括食品加工环境。
