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Antimicrobial compounds produced by Weissella confusa Cys2-2 strain inhibit Gram-negative bacteria growth

Abstract:

Antimicrobial compounds produced by lactic acid bacteria emerged as a promising group of agents for managing the growth of pathogens in food. Previously, we have isolated a bacteriocinogenic strain, Weissella confusa Cys2-2, producing active substances with inhibitory potential, however, its antimicrobial mechanism is still undefined. This study was aimed to determine the Cys2-2 bacteriocins mechanism of action against food pathogens using: agar-well diffusion and broth assay to evaluate the spectrum of inhibition and the minimum inhibitory concentration, Tricine-SDS-PAGE analysis to estimate the molecular weight, determination of the target cell viability with the Cys2-2 compounds applied as cell-free supernatant (CFS) and precipitated peptides (PP) with or without an chelator agent (EDTA) and evaluate the effect on the membrane integrity by monitoring the release of DNA/RNA molecules. The results revealed that Cys2-2 bacteriocin exerted its bactericidal effect by weakening of membrane integrity of target cells leading to cell death.