ABSTRACTCarnocyclin A (CCLA) is an antimicrobial peptide produced byCarnobacterium maltaromaticumATCC PTA-5313, which can be used to control the growth ofListeria monocytogenesin ready-to-eat meat products. The aim of this research was to elucidate the cellular responses ofL. monocytogenes08-5923 exposed to a sublethal dose of CCLA. Microarray, quantitative reverse transcription-PCR, tandem mass spectrometry, and electron microscopy were used to investigate the alteration in gene expression, protein production, and morphological changes in cells ofListeriafollowing treatment with CCLA. The genes involved in metabolism (baiE,trn, andpykA), cell wall synthesis (murZanddacB2), and cell division (clpEanddivIVA) were upregulated following a 15-min exposure to CCLA as a result of stress responses. Genes involved in cell division, cell wall synthesis, flagellar synthesis, and metabolism were downregulated after 4 h as a result of adaptation. Analysis of total soluble proteins confirmed the downregulation ofpykAandgndafter 4 h of exposure to CCLA. The absence of flagella was observed inL. monocytogenesfollowing 30 h of exposure to CCLA. A sublethal dose of CCLA induced adaptation inL. monocytogenes08-5923 by inhibition of expression of genes and proteins critical for synthesis of cell wall structures and maintaining metabolic functions. Both the mannose- and cellobiose-specific phosphotransferase systems could be targets for CCLA.
The heat-shock response of Listeria monocytogenes comprises genes involved in heat shock, cell division, cell wall synthesis, and the SOS response
