作者：张慧1, 郭晓梅1, 白婧2, 张森林1, 孙群2
作者单位：1. 四川大学轻工科学与工程学院，四川 成都 610064;
2. 四川大学生命科学学院 生物资源与生态环境教育部重点实验室，四川 成都 610064
关键词：3,3'-二吲哚甲烷;肠炎沙门氏菌;生物被膜;胞外基质
摘要：
研究3,3'-二吲哚甲烷(3,3'-Diindolemethane, DIM)对常见食源性致病菌肠炎沙门氏菌(Salmonella enteritidis)生物被膜的抑制作用及其机制。通过结晶紫染色法结合显微镜图像评估DIM对S. enteritidis生物被膜的抑制效果，并进一步研究DIM对生物被膜形成过程、细菌运动性、胞外多糖(extracellular polysaccharide, EPS)和胞外DNA (extracellular DNA, eDNA)的影响。结果显示，DIM对S. enteritidis的最小生物被膜抑制浓度(minimum biofilm inhibitory concentration, MBIC)为31.2 μmol/L；在15.6 ~ 31.2 μmol/L范围内随着浓度增加，生物被膜结构逐渐崩塌，在MBIC下，生物被膜厚度和生物量比对照组分别降低约68%和91% (P<0.05)；在生物被膜成熟阶段加入DIM的抑制率仅10%，显著低于在粘附和聚集阶段加入(P<0.05)，说明DIM主要抑制S. enteritidis细菌粘附及聚集过程。在15.6 ~ 31.2 μmol/L范围内，S. enteritidis游动直径和群集范围随着浓度增加而逐渐减小。此外，DIM在MBIC下使eDNA和EPS产生分别显著降低约67%和70%（P<0.05）。结果表明，DIM对S. enteritidis生物被膜形成有明显的抑制作用，且可能是通过阻碍细菌运动、抑制eDNA释放和EPS的产生防止细菌粘附和聚集，使生物被膜不能形成完整三维结构。
Antibiofilm activity of 3,3'-Diindolomethane on Salmonella enteritidis
ZHANG Hui1, GUO Xiaomei1, BAI Jing2, ZHANG Senlin1, SUN Qun2
1. College of Biomass Science and Engineering, Sichuan University, Chengdu 610064, China;
2. Key Laboratory of Bio-Resource and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu 610064, China
Abstract: The inhibitory effect of 3,3'-Diindolemethane (DIM) on the biofilm of Salmonella enteritidis, a common foodborne pathogen, and its mechanism were studied. The antibiofilm activity of DIM on S. enteritidis was evaluated by crystal violet staining and microscopic images, and the effects of DIM on biofilm formation process, bacterial motility, extracellular polysaccharide (EPS) and extracellular DNA (eDNA) were studied. The results showed that the minimum biofilm inhibitory concentration (MBIC) of DIM on S. enteritidis was 31.2 μmol/L. The biofilm structure gradually collapsed with the concentration increase in the range of 15.6 to 31.2 μmol/L. Compared with the control, the biofilm thickness and biomass significantly decreased by 68% and 91%, respectively (P<0.05). The inhibition rate of DIM on biofilm was only 10% if added in the mature stage, significantly lower than that in the adhesion and aggregation stage (P<0.05), indicating that DIM mainly inhibited the adhesion and aggregation of S. enteritidis. The swimming diameter and swarming range of S. enteritidis decreased with the concentration increase in the range of 15.6 to 31.2 μmol/L. In addition, DIM at 31.2 μmol/L significantly reduced eDNA and EPS release by 67% and 70%, respectively (P<0.05). Our results showed that DIM could significantly inhibit the formation of S. enteritidis biofilm, and prevent bacterial adhesion and aggregation by blocking bacterial movement, inhibiting the release of eDNA and the production of EPS, resulting in the failure of forming a complete three-dimensional structure of biofilm.
Keywords: 3,3'-Diindolemethane;Salmonella enteritidis;biofilm;extracellular matrix
2022, 48(1):60-67 收稿日期: 2021-04-10;收到修改稿日期: 2021-05-21
基金项目: 国家重点研发项目(2019YFE0103800); 四川省科技计划项目(2019YFH0113，2020ZYD111，2021YFN0092)
作者简介: 张慧（1997-），女，四川南充市人，硕士研究生，专业方向为食品质量与安全
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