Top Institute Food and Nutrition (TIFN), Wageningen, The Netherlands; Laboratory of Food Microbiology, Wageningen University, Wageningen, The Netherlands.
Top Institute Food and Nutrition (TIFN), Wageningen, The Netherlands; Wageningen Food and Biobased Research, Wageningen University and Research, Wageningen, The Netherlands.
Int J Food Microbiol. 2018 Apr 20;271:15-23. doi: 10.1016/j.ijfoodmicro.2018.02.013. Epub 2018 Feb 21.
Next to applications in fermentations, Lactobacillus plantarum is recognized as a food spoilage organism, and its dispersal from biofilms in food processing environments might be implicated in contamination or recontamination of food products. This study provides new insights into biofilm development by L. plantarum WCFS1 through comparative analysis of wild type and mutants affected in cell surface composition, including mutants deficient in the production of Sortase A involved in the covalent attachment of 27 predicted surface proteins to the cell wall peptidoglycan (ΔsrtA) and mutants deficient in the production of capsular polysaccharides (CPS1-4, Δcps1-4). Surface adhesion and biofilm formation studies revealed none of the imposed cell surface modifications to affect the initial attachment of cells to polystyrene while biofilm formation based on Crystal Violet (CV) staining was severely reduced in the ΔsrtA mutant and significantly increased in mutants lacking the cps1 cluster, compared to the wild-type strain. Fluorescence microscopy analysis of biofilm samples pointed to a higher presence of extracellular DNA (eDNA) in cps1 mutants and this corresponded with increased autolysis activity. Subsequent studies using Δacm2 and ΔlytA derivatives affected in lytic behaviour revealed reduced biofilm formation measured by CV staining, confirming the relevance of lysis for the build-up of the biofilm matrix with eDNA.
除了在发酵中的应用，植物乳杆菌被认为是一种食品腐败菌，其在食品加工环境中从生物膜中的分散可能与食品产品的污染或再污染有关。本研究通过比较野生型和突变体在细胞表面组成方面的差异，对植物乳杆菌 WCFS1 的生物膜发育提供了新的见解，包括参与 27 种预测表面蛋白与细胞壁肽聚糖共价连接的 Sortase A 产生缺陷的突变体（Δ srtA）和荚膜多糖（CPS1-4、Δ cps1-4）产生缺陷的突变体。表面粘附和生物膜形成研究表明，任何施加的细胞表面修饰都不会影响细胞最初对聚苯乙烯的附着，而基于结晶紫（CV）染色的生物膜形成在Δ srtA 突变体中严重减少，在缺乏 cps1 簇的突变体中显著增加，与野生型菌株相比。生物膜样本的荧光显微镜分析表明，cps1 突变体中存在更多的细胞外 DNA（eDNA），这与自溶活性的增加相对应。随后使用影响溶菌行为的Δ acm2 和Δ lytA 衍生物进行的研究表明，CV 染色测量的生物膜形成减少，证实了溶菌对生物膜基质中 eDNA 的积累的相关性。
