Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork, Ireland P61 C996; School of Food and Nutrition, University College Cork, Cork, Ireland T12 EH31.
Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork, Ireland P61 C996; APC Microbiome Ireland, Cork, Ireland T12 YT20.
J Dairy Sci. 2021 Mar;104(3):2632-2640. doi: 10.3168/jds.2020-19350. Epub 2020 Dec 25.
Nisin is a bacteriocin that is globally employed as a biopreservative in food systems to control gram-positive, and some gram-negative, bacteria. Here we tested the bioactivity of nisin A-producing Lactococcus lactis NZ9700 and producers of bioengineered variants thereof against representatives of the gram-negative genus Thermus, which has been associated with the pink discoloration defect in cheese. Starting with a total of 73 nisin variant-producing Lactococcus lactis, bioactivity against Thermus was assessed via agar diffusion assays, and 22 variants were found to have bioactivity greater than or equal to that of the nisin A-producing control. To determine to what extent this enhanced bioactivity was attributable to an increase in specific activity, minimum inhibitory concentrations were determined using the corresponding purified form of these 22 nisin A derivatives. From these experiments, nisin M17Q and M21F were identified as peptides with enhanced antimicrobial activity against the majority of Thermus target strains tested. In addition, several other peptide variants were found to exhibit enhanced specific activity against a subset of strains.
乳链菌肽是一种细菌素，在全球范围内被用作食品系统中的生物防腐剂，以控制革兰氏阳性菌和一些革兰氏阴性菌。在这里，我们测试了产乳链菌肽 A 的乳球菌 NZ9700 及其生物工程变异体的生物活性，以对抗与奶酪粉色变色缺陷有关的革兰氏阴性属 Thermus 的代表。从总共 73 种产乳链菌肽 A 的变异体乳球菌开始，通过琼脂扩散测定法评估了它们对 Thermus 的活性，发现 22 种变体的活性大于或等于产乳链菌肽 A 的对照。为了确定这种增强的生物活性在多大程度上归因于特定活性的增加，使用相应的 22 种乳链菌肽 A 衍生物的纯化形式确定了最小抑菌浓度。通过这些实验，鉴定出乳链菌肽 M17Q 和 M21F 是对大多数测试的 Thermus 目标菌株具有增强抗菌活性的肽。此外，还发现其他几种肽变体对亚组菌株表现出增强的特定活性。
