Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo (FCFRP-USP), Av. do Café s/n, Ribeirão Preto, São Paulo, 14040-903, Brazil.
Faculdade de Farmácia, Universidade Federal de Goiás, Rua 240, esquina com 5ª Avenida, s/n, Setor Leste Universitário, Goiânia, Goiás, 74605-170, Brazil.
Braz J Microbiol. 2019 Apr;50(2):501-506. doi: 10.1007/s42770-019-00069-3. Epub 2019 Mar 13.
Studying biofilm dispersal is important to prevent Listeria monocytogenes persistence in food processing plants and to avoid finished product contamination. Reactive oxygen and nitrogen intermediates (ROI and RNI, respectively) may trigger cell detachment from many bacterial species biofilms, but their roles in L. monocytogenes biofilms have not been fully investigated. This study reports on ROI and RNI quantification in Listeria monocytogenes biofilms formed on stainless steel and glass surfaces; bacterial culture and microscopy combined with fluorescent staining were employed. Nitric oxide (NO) donor and inhibitor putative effects on L. monocytogenes dispersal from biofilms were evaluated, and transcription of genes (prfA, lmo 0990, lmo 0807, and lmo1485) involved in ROI and RNI stress responses were quantified by real-time PCR (qPCR). Microscopy detected the reactive intermediates NO, peroxynitrite, HO, and superoxide in L. monocytogenes biofilms. Neither NO donor nor inhibitors interfered in L. monocytogenes growth and gene expression, except for lmo0990, which was downregulated. In conclusion, ROI and RNI did not exert dispersive effects on L. monocytogenes biofilms, indicating that this pathogen has a tight control for protection against oxidative and nitrosative stresses.
研究生物膜的分散对于防止李斯特菌在食品加工厂中的持续存在和避免成品污染非常重要。活性氧和氮中间体（分别为 ROI 和 RNI）可能会触发许多细菌物种生物膜中的细胞脱落，但它们在李斯特菌生物膜中的作用尚未得到充分研究。本研究报告了在不锈钢和玻璃表面形成的李斯特菌生物膜中 ROI 和 RNI 的定量；采用细菌培养和显微镜结合荧光染色。评估了一氧化氮（NO）供体和抑制剂对李斯特菌生物膜分散的潜在影响，并通过实时 PCR（qPCR）定量了参与 ROI 和 RNI 应激反应的基因（prfA、lmo0990、lmo0807 和 lmo1485）的转录。显微镜检测到李斯特菌生物膜中的活性中间体 NO、过氧亚硝酸盐、HO 和超氧化物。NO 供体和抑制剂都没有干扰李斯特菌的生长和基因表达，除了 lmo0990 被下调。总之，ROI 和 RNI 对李斯特菌生物膜没有分散作用，表明该病原体对氧化和硝化应激有严格的控制。
