Liu Xiaoji, Basu Urmila, Miller Petr, McMullen Lynn M
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada.
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada
Appl Environ Microbiol. 2014 Jul;80(13):3835-41. doi: 10.1128/AEM.00350-14. Epub 2014 Apr 18.
Carnocyclin A (CCLA) is an antimicrobial peptide produced by Carnobacterium maltaromaticum ATCC PTA-5313, which can be used to control the growth of Listeria monocytogenes in ready-to-eat meat products. The aim of this research was to elucidate the cellular responses of L. monocytogenes 08-5923 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 of Listeria following treatment with CCLA. The genes involved in metabolism (baiE, trn, and pykA), cell wall synthesis (murZ and dacB2), and cell division (clpE and divIVA) 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 of pykA and gnd after 4 h of exposure to CCLA. The absence of flagella was observed in L. monocytogenes following 30 h of exposure to CCLA. A sublethal dose of CCLA induced adaptation in L. monocytogenes 08-5923 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.
嗜麦芽寡养单胞菌环素A（CCLA）是由麦芽香嗜冷杆菌ATCC PTA - 5313产生的一种抗菌肽，可用于控制即食肉类产品中单核细胞增生李斯特菌的生长。本研究的目的是阐明暴露于亚致死剂量CCLA下的单核细胞增生李斯特菌08 - 5923的细胞反应。利用微阵列、定量逆转录PCR、串联质谱和电子显微镜来研究用CCLA处理后李斯特菌细胞的基因表达变化、蛋白质产生及形态变化。暴露于CCLA 15分钟后，由于应激反应，参与代谢（baiE、trn和pykA）、细胞壁合成（murZ和dacB2）以及细胞分裂（clpE和divIVA）的基因被上调。4小时后，由于适应性，参与细胞分裂、细胞壁合成、鞭毛合成和代谢的基因被下调。对总可溶性蛋白的分析证实，暴露于CCLA 4小时后pykA和gnd被下调。暴露于CCLA 30小时后，在单核细胞增生李斯特菌中观察到鞭毛缺失。亚致死剂量的CCLA通过抑制对细胞壁结构合成和维持代谢功能至关重要的基因和蛋白质的表达，诱导单核细胞增生李斯特菌08 - 5923产生适应性。甘露糖特异性和纤维二糖特异性磷酸转移酶系统都可能是CCLA的作用靶点。
