Abstract

Quorum sensing inhibitors (QSIs) can block the quorum sensing system and might be useful in therapy of drug-resistant bacterial infections. To explore the anti-quorum sensing actinomycetes from marine habitats, in this study, a marine actinobacterium exhibiting strong anti-quorum sensing activity was isolated from marine sediment and identified as Nocardiopsis dassonvillei JS106. Effects of different culture media on the bioactivity and metabolites production of JS106 were investigated by using single-factor and orthogonal experiments. The results showed that soybean meal and NaCl were two important factors in the culture medium, and could significantly affect both the bioactivity and metabolites production of JS106. By culturing in the optimized medium containing 10 g/L soluble starch, 10 g/L soybean meal, and 15 g/L NaCl at pH 6.5, both metabolites production and anti-quorum sensing activity of JS106 were significantly increased (302 and 241%, respectively) compared to the original condition. The culture liquid of JS106 also showed strong anti-biofilm activity against Staphylococcus aureus and Pseudomonas aeruginosa with the inhibition rate of 77.94 and 50.56% at the concentration of 20 vol %, while it did not inhibit the growth of planktonic cells. Questiomycin A and a new compound 2-hydroxyacetate-3-hydroxyacetamido-phenoxazine (HHP) were isolated and identified from the cultures of JS106. The anti-quorum sensing activities (IC₅₀) of questiomycin A and HHP against violacein production by Chromobacterium violaceum 12472 were 6.82 and 23.59 μg/mL, respectively. The strong anti-quorum sensing activity of N. dassonvillei JS106 indicated that this strain and its active phenoxazine metabolites could have good potential in anti-quorum sensing related applications.

中文翻译：

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一种抗群体感应海洋放线放线杆菌Nocardiopsis dassonvillei JS106的培养基优化和活性化合物的研究

摘要

群体感应抑制剂（QSI）可以阻止群体感应系统，并可能在耐药细菌感染的治疗中有用。为了探索来自海洋栖息地的抗群体感应放线菌，在这项研究中，从海洋沉积物中分离出具有较强抗群体感应活性的海洋放线菌，并将其鉴定为达氏诺卡氏菌。JS106。通过单因素和正交试验研究了不同培养基对JS106生物活性和代谢产物产生的影响。结果表明，豆粕和NaCl是培养基中的两个重要因素，它们可以显着影响JS106的生物活性和代谢产物的产生。通过在pH 6.5的含有10 g / L可溶性淀粉，10 g / L大豆粉和15 g / L NaCl的优化培养基中培养，JS106的代谢产物产生和抗群体感应活性均显着提高（302和241％ ，分别与原始状态进行比较。JS106的培养液还对金黄色葡萄球菌和铜绿假单胞菌具有很强的抗生物膜活性。浓度为20vol％时，抑制率分别为77.94和50.56％，而对浮游细胞的生长没有抑制作用。从JS106的培养物中分离并鉴定了Questiomycin A和一种新的化合物2-羟基乙酸酯-3-羟基乙酰氨基-苯恶嗪（HHP）。Questiomycin A和HHP对由紫色杆菌12472产生的紫色素的抗群体感应活性（IC ₅₀）分别为6.82和23.59μg/ mL。N. dassonvillei JS106具有很强的抗群体感应作用，表明该菌株及其活性吩恶嗪代谢物在抗群体感应相关应用中具有良好的潜力。