Escherichia coli (E. coli) is the principal pathogen that causes biofilm formation. Biofilms are associated with infectious diseases and antibiotic resistance. This study employed proteomic analysis to identify differentially expressed proteins after coculture of E. coli with Lactobacillus rhamnosus GG (LGG) microcapsules. To explore the relevant protein abundance changes after E. coli and LGG coculture, label-free quantitative proteomic analysis and qRT-PCR were applied to E. coli and LGG microcapsule groups before and after coculture, respectively. The proteomic analysis characterised a total of 1655 proteins in E. coli K12MG1655 and 1431 proteins in the LGG. After coculture treatment, there were 262 differentially expressed proteins in E. coli and 291 in LGG. Gene ontology analysis showed that the differentially expressed proteins were mainly related to cellular metabolism, the stress response, transcription and the cell membrane. A protein interaction network and Kyoto Encyclopaedia of Genes and Genomes (KEGG) pathway analysis indicated that the differentiated proteins were mainly involved in the protein ubiquitination pathway and mitochondrial dysfunction. These findings indicated that LGG microcapsules may inhibit E. coli biofilm formation by disrupting metabolic processes, particularly in relation to energy metabolism and stimulus responses, both of which are critical for the growth of LGG. Together, these findings increase our understanding of the interactions between bacteria under coculture conditions.

中文翻译：

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无标记定量蛋白质组学分析鼠李糖乳杆菌GG对共培养中大肠杆菌生物膜形成的抑制作用

大肠杆菌 (E. coli) 是导致生物膜形成的主要病原体。生物膜与传染病和抗生素耐药性有关。本研究采用蛋白质组学分析来鉴定大肠杆菌与鼠李糖乳杆菌 GG (LGG) 微胶囊共培养后的差异表达蛋白。为了探讨大肠杆菌和LGG共培养后相关蛋白质丰度的变化，分别对共培养前后的大肠杆菌和LGG微胶囊组进行无标记定量蛋白质组学分析和qRT-PCR。蛋白质组分析共鉴定了大肠杆菌 K12MG1655 中的 1655 个蛋白质和 LGG 中的 1431 个蛋白质。共培养处理后，大肠杆菌中有262个差异表达蛋白，LGG中有291个差异表达蛋白。基因本体分析表明差异表达蛋白主要与细胞代谢、应激反应、转录和细胞膜有关。蛋白质相互作用网络和京都基因与基因组百科全书（KEGG）通路分析表明，分化蛋白主要涉及蛋白质泛素化通路和线粒体功能障碍。这些发现表明，LGG 微胶囊可能通过破坏代谢过程来抑制大肠杆菌生物膜的形成，特别是与能量代谢和刺激反应有关的过程，这两者对于 LGG 的生长至关重要。总之，这些发现增加了我们对共培养条件下细菌之间相互作用的理解。