Liu Xiaoji, Basu Urmila, Miller Petr, McMullen Lynn M
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada.
Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2P5, Canada.
Food Microbiol. 2017 May;63:153-158. doi: 10.1016/j.fm.2016.11.009. Epub 2016 Nov 18.
This study reports the gene expression and filamentation in Listeria monocytogenes 08-5923 following exposure to food preservatives sodium lactate (NaL) and sodium diacetate (SD). L. monocytogenes 08-5923 was challenged with a mixture of NaL/SD, NaL or sodium acetate at 37 °C in tryptic soy broth. In the initial study, L. monocytogenes 08-5923 was exposed to NaL/SD for 24 h. The transcriptome was investigated by RNA sequencing. A stress response network was discovered in L. monocytogenes 08-5923, which is mediated by genes encoding two-component systems (hisJ, lisK, OmpR family gene, resE) and RNA polymerase factors (sigC, sigH). NaL/SD resulted in the down-regulation of genes in glycolysis (pykA, eno, fbaA, pgm) and up-regulation of genes in DNA repair (radC), cell division (ftsE) and cell structure synthesis (flagella synthesis: flgK, fliF, fliD). Filamentation was monitored by flow cytometry. NaL/SD mixture resulted in filamentation in L. monocytogenes 08-5923. Longer exposure was required to induce filamentation in L. monocytogenes for SD (24 h) than for NaL (8 h) when cells were exposed to individual salt. The quantitative real time PCR analysis revealed the down-regulation of ftsE in filamented cells of Listeria exposed to NaL or sodium acetate.
本研究报告了单核细胞增生李斯特菌08 - 5923在接触食品防腐剂乳酸钠（NaL）和双乙酸钠（SD）后的基因表达及丝状化情况。将单核细胞增生李斯特菌08 - 5923在37°C的胰蛋白胨大豆肉汤中用NaL/SD混合物、NaL或乙酸钠进行挑战。在初步研究中，将单核细胞增生李斯特菌08 - 5923暴露于NaL/SD中24小时。通过RNA测序研究转录组。在单核细胞增生李斯特菌08 - 5923中发现了一个应激反应网络，该网络由编码双组分系统（hisJ、lisK、OmpR家族基因、resE）和RNA聚合酶因子（sigC、sigH）的基因介导。NaL/SD导致糖酵解相关基因（pykA、eno、fbaA、pgm）下调，DNA修复相关基因（radC）、细胞分裂相关基因（ftsE）和细胞结构合成相关基因（鞭毛合成：flgK、fliF、fliD）上调。通过流式细胞术监测丝状化情况。NaL/SD混合物导致单核细胞增生李斯特菌08 - 5923出现丝状化。当细胞暴露于单一盐时，诱导单核细胞增生李斯特菌丝状化所需的SD暴露时间（24小时）比NaL（8小时）更长。定量实时PCR分析显示，暴露于NaL或乙酸钠的李斯特菌丝状化细胞中ftsE下调。
