No abstract

Fresh green tea (GT) is commonly considered to have better sensory flavor and higher commercial value than longterm-stored GT; however, the chemical variations during storage are unclear. In this study, the chemical profiles of stored GT were surveyed among time-series samples from 0 to 19 months using a nontargeted metabolomics method. Seven N-ethyl-2pyrrolidinone-substituted flavan-3-ols (EPSFs) increased from 0.022 ± 0.019 to 3.212 ± 0.057 mg/g within 19 months (correlation coefficients with storage duration ranging from 0.936 to 0.965), and they were the most significantly increased compounds among the 127 identified compounds. Two representative EPSFs (R-EGCG-cThea and S-EGCG-cThea) possess potential antiinflammatory properties by suppressing the expression, phosphorylation, and nuclear translocation of nuclear factor kappa-B (NF-κB) p65 in lipopolysaccharide-stimulated macrophages based on western blotting and immunofluorescence results. In conclusion, EPSFs were found to be marker compounds for stored GT and showed potential anti-inflammatory activity by regulating the NF-κB signaling pathway.

Background 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. Methods 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. Results 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. Conclusions 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.

Background: Escherich coli (E.coli) is the principal pathogen that causes biofilm formation; the latter is associated with infectious diseases and antibiotic resistance. In our previous work, we demonstrated that probiotic microcapsules have superior biofilm inhibition capacity compared to probiotic sterile culture supernatant. Herein, the mechanism of the inhibition effects was investigated using label-free quantitative proteomics analysis. Results:The proteomic analysis characterized a total of 1655 proteins in E.coli K12MG1655 and 1431 proteins in Lactobacillus rhamnosus GG (LGG). Among them, after coculture treatment, there were 262 and differentially expressed proteins that were specific for E.coli and 291 for LGG. The differentially expressed proteins after coculture were related to cellular metabolism, the stress response, transcription, and the cell membrane. In addition, we identified five strain-specific genes in E.coli and LGG, respectively, which were consistent with the proteomics results. Conclusions:These findings indicate that LGG microcapsules may inhibit E.coli biofilm inhibition 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. BackgroundBiofilms are complex bacterial community structures that can attach to a surface. They are connected to this surface via extracellular polymeric substances (EPS) which form a matrix composed primarily of polysaccharides, proteins, and DNA; this encapsulates the bacteria [1]. Biofilms not only cause economic losses, but also present a public health hazard. This is because the bacteria present within biofilms are much more resistant to antibiotics, disinfectants [2], and the host immune system effectors [3]. Therefore, it is critical to uncover effective non-toxic, or less toxic, antifungal agents with novel modes of action.A recent study suggested that probiotic supernatants have antipathogenic properties [4], which implies that probiotics may inhibit biofilm formation through cell-cell communication. However, there