BioNano Lab, School of Engineering, University of Guelph, Ontario, Guelph, N1G 2W1, Canada.
Lab Chip. 2014 Mar 7;14(5):938-46. doi: 10.1039/c3lc51138c.
Listeria monocytogenes remains a significant foodborne pathogen due to its virulence and ability to become established in food processing facilities. The pathogen is characterized by its ability to grow over a wide temperature range and withstand a broad range of stresses. The following reports on the chemotaxis and motility of the L. monocytogenes when exposed to relatively small concentrations of acetic acid. Using the developed nanoporous microfluidic device to precisely modulate the cellular environment, we exposed the individual Listeria cells to acetic acid and, in real time and with high resolution, observed how the cells reacted to the change in their surroundings. Our results showed that concentrations of acetic acid below 10 mM had very little, if any, effect on the motility. However, when exposed to 100 mM acetic acid, the cells exhibited a sharp drop in velocity and displayed a more random pattern of motion. These results indicate that at appropriate concentrations, acetic acid has the ability to disable the flagellum of the cells, thus impairing their motility. This drop in motility has numerous effects on the cell; its main effects being the obstruction of the cell's ability to properly form biofilms and a reduction in the overall infectivity of the cells. Since these characteristics are especially useful in controlling the proliferation of L. monocytogenes, acetic acid shows potential for application in the food industry as an active compound in designing a food packaging environment and as an antimicrobial agent.
李斯特菌仍然是一种重要的食源性病原体，因为它的毒性和在食品加工设施中定殖的能力。该病原体的特点是能够在很宽的温度范围内生长，并能承受广泛的压力。以下是关于李斯特菌在接触相对较小浓度的乙酸时的趋化性和运动性的报告。通过使用开发的纳米多孔微流控装置精确调节细胞环境，我们将单个李斯特菌细胞暴露于乙酸中，并实时高分辨率地观察细胞如何对周围环境的变化做出反应。我们的结果表明，浓度低于 10 mM 的乙酸对运动性几乎没有影响。然而，当暴露于 100 mM 的乙酸时，细胞的速度急剧下降，并显示出更随机的运动模式。这些结果表明，在适当的浓度下，乙酸能够使细胞的鞭毛失活，从而损害其运动性。这种运动性的下降对细胞有许多影响；其主要影响是阻碍了细胞形成生物膜的能力，并降低了细胞的整体感染力。由于这些特性在控制李斯特菌的增殖方面特别有用，因此乙酸有望在食品工业中作为设计食品包装环境的活性化合物和作为抗菌剂应用。
