Whole-transcriptome analysis reveals mechanisms underlying antibacterial activity and biofilm inhibition by a malic acid combination (MAC) in Pseudomonas
Document Type
Article
Publication Date
12-1-2023
Abstract
Background. Pseudomonas aeruginosa is a highly prevalent bacterial species known for its ability to cause various infections and its remarkable adaptability and biofilmforming capabilities. In earlier work, we conducted research involving the screening of 33 metabolites obtained from a commercial source against two prevalent bacterial strains, Escherichia coli and Staphylococcus aureus. Through screening assays, we discovered a novel malic acid combination (MAC) consisting of malic acid, citric acid, glycine, and hippuric acid, which displayed significant inhibitory effects. However, the precise underlying mechanism and the potential impact of the MAC on bacterial biofilm formation remain unknown and warrant further investigation.Methods. To determine the antibacterial effectiveness of the MAC against Pseudomonas aeruginosa, we conducted minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) assays. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) techniques were employed to observe bacterial morphology and biofilm formation. We further performed a biofilm inhibition assay to assess the effect of the MAC on biofilm formation. Whole-transcriptome sequencing and bioinformatics analysis were employed to elucidate the antibacterial mechanism of the MAC. Additionally, the expression levels of differentially expressed genes were validated using the real-time PCR approach.Results. Our findings demonstrated the antibacterial activity of the MAC against P. aeruginosa. SEM analysis revealed that the MAC can induce morphological changes in bacterial cells. The biofilm assay showed that the MAC could reduce biofilm formation. Whole-transcriptome analysis revealed 1093 differentially expressed genes consisting of 659 upregulated genes and 434 downregulated genes, in response to the MAC treatment. Mechanistically, the MAC inhibited P. aeruginosa growth by targeting metabolic processes, secretion system, signal transduction, and cell membrane functions, thereby potentially compromising the survival of this human pathogen. This study provides valuable insights into the antibacterial and antibiofilm activities of the MAC, a synergistic and cost-effective malic acid combination, which holds promise as a potential therapeutic drug cocktail for treating human infectious diseases in the future.
Keywords
Malic Acid, Antibacterial activity, Biofilm, Whole-transcriptome, Pseudomonas aeruginosa
Divisions
InstituteofBiologicalSciences
Funders
Wenzhou-Kean University (5000105),Wenzhou Municipal Key Lab for Biomedical and Biopharmaceutical Informatics of Wenzhou-Kean University (20211227000125),Wenzhou Science and Technology "Qing Miao Project"
Publication Title
PeerJ
Volume
11
Publisher
PeerJ
Publisher Location
341-345 OLD ST, THIRD FLR, LONDON, EC1V 9LL, ENGLAND