Mutations in gltB and gltC reduce oxidative stress tolerance and biofilm formation in Listeria monocytogenes 4b G
Mutations in gltB and gltC reduce oxidative stress tolerance and biofilm formation in Listeria monocytogenes 4b G
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gltB 和 gltC 突变降低单核细胞增生李斯特菌 4b G 的氧化应激耐受性和生物膜形成
DOI：
10.1016/j.ijfoodmicro.2013.02.023
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发表时间：
2013-05-15
影响因子：
5.4
通讯作者：
Knochel, Susanne
中科院分区：
文献类型：
--
作者：
Huang, Yanyan;Suo, Yujuan;Knochel, Susanne
食源性病原体单核细胞增生李斯特菌具有在食品加工环境中的表面上持续存在的能力，并且该生物体对环境压力具有抵抗力。本研究以L.鉴定并表征了显示减少的生物膜形成和对氧化应激敏感性的单核细胞增多症4 b G。通过反向PCR鉴定gltB基因内的转座子插入位点。gltC基因位于上游，据报道与gltB转录不同。构建了gltB和gltC缺失的突变体，与野生型相比，两者均显示出减少的生物膜形成和增加的对H2 O2的敏感性。在野生型菌株中，gltB和gltC的表达诱导约8倍和14倍，分别通过定量RT-PCR，暴露于H2 O2，提供进一步的证据表明，它们的基因产物可能参与对氧化应激的反应。另外，在H2 O2诱导后，与野生型相比，Delta gltC和Delta gltB中的gltC表达分别下调约4倍（p < 0.05）和3倍（p < 0.05）。这些数据表明氧化应激条件下gltB和gltC表达之间可能存在相互调节，部分解释了Delta gltB和Delta gltC相似的氧化应激反应。此外，与野生型相比，Delta gltB和Delta gltC对玻璃表面的粘附性降低，而野生型和突变株的细胞运动性相似。据推测，一些与细胞运动无关的细胞表面特征可能通过gltB或gltC的失活而引入突变体中，这可能导致生物膜形成的减少。我们的结论是，gltB和gltC都参与了生物膜的形成以及氧化应激耐受在L。单核细胞增生4 b G，通过途径，但仍不清楚。(C)2013爱思唯尔有限公司版权所有。
The foodborne pathogen Listeria monocytogenes has the capability to persist on surfaces in food-processing environments, and the organism is resistant to environmental stresses. In this study, a Tn917 insertion mutant of L. monocytogenes 4b G showing reduced biofilm formation and sensitivity to oxidative stress was identified and characterized. The transposon insertion site within the gltB gene was identified by inverse PCR. The gltC gene is located, upstream and is reported to be transcribed divergently from gltB. Mutants with deletions in gltB and gltC were constructed and both showed reduced biofilm formation and increased sensitivity to H2O2 compared to the wild-type. In the wild-type strain, gltB and gltC expressions were induced approximately 8-fold and 14-fold by quantitative RT-PCR, respectively, with exposure to H2O2, providing further evidence that their gene products may be involved in the response to oxidative stress. In addition, after the induction by H2O2 and compared with the wild-type, the gltB expression in Delta gltC and the gltC expression in Delta gltB were down-regulated about 4-fold (p < 0.05) and 3-fold (p < 0.05) respectively. These data demonstrate a possible mutual regulation between gltB and gltC expressions under oxidative stress conditions, partly explaining the similar oxidative stress responses of Delta gltB and Delta gltC. Furthermore, Delta gltB and Delta gltC exhibited decreased adherence to a glass surface compared to the wild-type, while the cell motility of wild-type and mutant strains was similar. It is hypothesized that some cell surface characteristics unrelated with cell motility may be introduced into the mutants by the inactivation of gltB or gltC, which might lead to the reduction in biofilm formation. We conclude that both gltB and gltC are involved in the biofilm formation as well as the oxidative stress tolerance in L. monocytogenes 4b G, by pathways that remain yet unclear. (C) 2013 Elsevier B.V. All rights reserved.