Antibacterial Efficacy and Mechanism of Mannosylerythritol Lipids-A on Listeria monocytogenes

Abstract

Mannosylerythritol lipids-A (MEL-A) is a novel biosurfactant with excellent surface activity and potential biomedical applications. In this study, we explored the antibacterial activity and the underlying mechanisms of MEL-A against the important food-borne pathogen Listeria monocytogenes. The bacterial growth and survival assays revealed a remarkable antibacterial activity of MEL-A. Since MEL-A is a biosurfactant, we examined the cell membrane integrity and morphological changes of MEL-A-treated bacteria by biochemical assays and flow cytometry analysis and electron microscopes. The results showed obvious damaging effects of MEL-A on the cell membrane and morphology. To further explore the antibacterial mechanism of MEL-A, a transcriptome analysis was performed, which identified 528 differentially expressed genes (DEGs). Gene ontology (GO) analysis revealed that the gene categories of membrane, localization and transport were enriched among the DEGs, and the analysis of the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways demonstrated significant changes in the maltodextrin ABC transporter system and stress response system. Furthermore, the growth of L. monocytogenes could also be significantly inhibited by MEL-A in milk, a model of a real food system, suggesting that MEL-A could be potentially applied as an natural antimicrobial agent to control food-borne pathogens in the food industry.

Contributions of Glycolipid Biosurfactants and Glycolipid-Modified Materials to Antimicrobial Strategy: A Review

“…Specifically, glycolipids are able to insert into the lipid bilayer relying on their unique similar structure, leading to the deformation and collapse of membrane skeleton physically as well as a conformational change of related proteins functionally. As the main member of membrane proteins, ATP-binding cassette (ABC) transporters are responsible for transmembrane migration of material and energy transformation via ATP hydrolysis, and it has been proven that glycolipids have rendered the disorder of movement across the membrane and material supplement by regulating the different expression of related genes, which might be internal reason accounting for the final cell apoptosis [ 78 , 116 ]. Except for membrane-mediated modes, correlational researches also discovered the generation of ROS in bacteria and fungi [ 53 , 59 ].…”

“…Shu et al investigated the antibacterial efficacy of MELs against Bacillus cereus and Staphylococcus aureus and concluded the mode of action involved the disruption of the cell membrane, leakage of cellular contents, the collapse of the whole cytoskeleton as well as induced cell apoptosis [ 76 , 77 ]. Liu et al observed the same phenomenon in Listeria monocytogenes treated by MEL-A (32 μg/mL), and further transcriptome analysis demonstrated that the differentially expressed genes were enriched in the ABC transporter system, which verified the disorder of transmembrane protein played a key role in MEL-mediated cell death [ 78 ].…”

Antibacterial Activity and Components of the Methanol-Phase Extract from Rhizomes of Pharmacophagous Plant Alpinia officinarum Hance

“…To determine possible mechanisms underlying the bacteriostatic activity of the GMPE, the bacterial cell surface hydrophobicity, membrane fluidity and permeability of the five highly inhibited strains were analyzed, as these are key parameters of bacterial cell response to adverse environments [12].…”

“…The changed cell-membrane fluidity possibly resulted in cytoplasmic membrane damage and subsequent cellular content leakage, and even cell death. The bacterial cell membrane is an efficient permeable barrier which can exclude macromolecules and hydrophobic substances [12]. The influence of the GMPE on bacterial cell inner membrane (CIM) permeability was examined using the probe O-nitrophenyl-β-Dgalactopyranoside (ONPG); the results are shown in Figure 3A-E.…”

Optimization and Kinetic Modeling of a Fed-Batch Fermentation for Mannosylerythritol Lipids (MEL) Production With Moesziomyces aphidis

“…Besides their surface activity and biodegradability, which make them suitable as fully bio-based surfactants for household and personal care applications, for example, MELs also possess some additional interesting properties. These are for example the ability to induce cell differentiation in mammalian cells ( Isoda et al, 1997 ; Isoda and Nakahara, 1997 ; Wakamatsu et al, 2001 ), to interact with proteins or antibodies ( Konishi et al, 2007 ; Fan et al, 2018 ), and to inhibit the growth of Gram-positive bacteria ( Kitamoto et al, 1993 ; Liu et al, 2020 ; Shu et al, 2020 ). Moreover, they are reported to possess a moisturizing activity towards human skin ( Morita et al, 2009b ; Yamamoto et al, 2012 ) and hair ( Morita et al, 2010a ; Morita et al, 2010b ).…”