Laboratory of Food Microbiology, Wageningen University and Research, Wageningen, The Netherlands.
Laboratory of Biochemistry, Wageningen University and Research, Wageningen, The Netherlands.
Food Res Int. 2024 Jan;175:113609. doi: 10.1016/j.foodres.2023.113609. Epub 2023 Oct 20.
The dynamics of the enrichment-based detection procedure of the foodborne pathogen Listeria monocytogenes from food still remains poorly understood. This enrichment is crucial in the reliable detection of this pathogen and more insight into the recovery mechanism during this step is important to advance our understanding of lag phase behaviour during enrichment. In this study we combined transcriptomic and proteomic analyses to better understand the physiological processes within the lag phase of L. monocytogenes during enrichment. Upon transfer of BHI-cultured stationary phase L. monocytogenes cells to half-Fraser enrichment broth (HFB), motility-associated genes and proteins were downregulated, while expression of metal uptake transporters, resuscitation-promoting factors that stimulate growth from dormancy, antibiotic efflux pumps and oxidative stress proteins were upregulated. Next to this, when cells with a heat stress history were cultured in enrichment broth, proteins necessary for recovery were upregulated with functions in DNA-damage repair, protein refolding, cell-wall repair, and zinc transport. Proteomic results pointed to possible factors that support shortening the lag duration, including the addition of 10 µM zinc and the addition of spent HFB containing presumed concentrations of resuscitation-promoting factors. However, these interventions did not lead to biologically relevant reduction of lag phase. Also, when cells were enriched in spent HFB, final cell concentrations were similar to enrichments in fresh HFB, indicating that the enrichment broth seems not to lack critical substrates. Concludingly, this study gives insight into the proteomic changes in the lag phase during enrichment and shows that supplementation of HFB is not the best strategy to optimize the current enrichment method.
食源性致病菌单核细胞增生李斯特菌的基于富集的检测程序的动力学仍然知之甚少。这种富集对于可靠地检测这种病原体至关重要，更深入地了解在富集过程中的回收机制对于我们深入了解富集过程中的迟滞期行为非常重要。在这项研究中，我们结合了转录组学和蛋白质组学分析，以更好地了解单核细胞增生李斯特菌在富集过程中的迟滞期内的生理过程。当将 BHI 培养的静止期单核细胞增生李斯特菌细胞转移到半 Fraser 富集肉汤 (HFB) 中时，运动相关基因和蛋白质下调，而金属摄取转运蛋白、刺激休眠生长的复苏促进因子、抗生素外排泵和氧化应激蛋白的表达上调。除此之外，当具有热应激历史的细胞在富集肉汤中培养时，与 DNA 损伤修复、蛋白质重折叠、细胞壁修复和锌转运相关的恢复所需的蛋白质上调。蛋白质组学结果指出了可能支持缩短迟滞期的因素，包括添加 10µM 锌和添加含有推定复苏促进因子浓度的消耗 HFB。然而，这些干预措施并没有导致生物学上相关的迟滞期缩短。此外，当细胞在消耗的 HFB 中富集时，最终细胞浓度与在新鲜 HFB 中的富集相似，这表明富集肉汤似乎不缺乏关键底物。总之，本研究深入了解了富集过程中迟滞期的蛋白质组学变化，并表明补充 HFB 不是优化当前富集方法的最佳策略。
