Laboratório de Bioquímica e Microbiologia Aplicada, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
Laboratório de Bioquímica e Microbiologia Aplicada, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brazil.
Int J Food Microbiol. 2021 May 16;346:109170. doi: 10.1016/j.ijfoodmicro.2021.109170. Epub 2021 Mar 18.
The ability of Listeria monocytogenes grow on ready-to-eat food is a major concern in food safety. Natural antimicrobials, such as nisin, can be used to control this pathogen, but the increasing reports of nisin tolerance and resistance make necessary novel approaches to increase its effectiveness, such as encapsulation. The goal of this study was to investigate how L. monocytogenes ATCC7644 regulates and shapes its proteome in response to sublethal doses of nisin and nisin-loaded phosphatidylcholine liposomes (lipo-nisin), compared to untreated cells growing under optimal conditions. Total proteins were extracted from L. monocytogenes cells treated for 1 h with free and lipo-nisin. As result, of 803 proteins that were initially identified, 64 and 53 proteins were differentially upregulated and downregulated respectively, in the treatments with nisin and lipo-nisin. Changes of Listeria proteome in response to treatments containing nisin were mainly related to ATP-binding cassette (ABC) transporter systems, transmembrane proteins, RNA-binding proteins and diverse stress response proteins. Some of the proteins uniquely detected in samples treated with free nisin were the membrane proteins SecD, Lmo1539 and the YfhO enzyme, which are related to translocation of L. monocytogenes virulence factors, activation of the LiaR-mediated stress defense and glycosylation of wall teichoic acid, respectively. The L. monocytogenes treated with liposome encapsulated nisin showed no expression of some stress response factors as compared with the free nisin, suggesting a reduction of stress mediated response and production of nisin-resistance factors by exposure to encapsulated nisin.
李斯特菌在即食食品上生长的能力是食品安全的主要关注点。天然抗菌剂，如乳链菌肽，可以用来控制这种病原体，但是越来越多的关于乳链菌肽耐药性和抗性的报告使得有必要采用新的方法来提高其有效性，例如包封。本研究的目的是研究李斯特菌 ATCC7644 如何在亚致死剂量的乳链菌肽和乳链菌肽负载的磷脂酰胆碱脂质体（脂质体乳链菌肽）下调节和塑造其蛋白质组，与在最佳条件下生长的未处理细胞相比。从用游离和脂质体乳链菌肽处理 1 小时的李斯特菌细胞中提取总蛋白。结果，在最初鉴定的 803 种蛋白质中，有 64 种和 53 种蛋白质分别在乳链菌肽和脂质体乳链菌肽处理中上调和下调。对含有乳链菌肽的处理的李斯特菌蛋白质组的变化主要与 ATP 结合盒（ABC）转运系统、跨膜蛋白、RNA 结合蛋白和多种应激反应蛋白有关。在游离乳链菌肽处理的样品中唯一检测到的一些蛋白质是膜蛋白 SecD、Lmo1539 和 YfhO 酶，它们分别与李斯特菌毒力因子的易位、LiaR 介导的应激防御的激活以及细胞壁磷壁酸的糖基化有关。与游离乳链菌肽相比，用脂质体包封的乳链菌肽处理的李斯特菌没有表达一些应激反应因子，这表明暴露于包封的乳链菌肽会减少应激介导的反应和产生乳链菌肽抗性因子。
