ABSTRACT

The present study explored the cooperative effect of both alanine (Ala) and gentamicin (Gent) on metabolic mechanisms by which exogenous Ala potentiates Gent to kill antibiotic-resistant Vibrio alginolyticus. To test this, GC-MS-based metabolomics was used to characterize Ala-, Gent- and both-induced metabolic profiles, identifying nitric oxide (NO) production pathway as the most key clue to understand metabolic mechanisms. Gent, Ala and both led to low, lower and lowest activity of total nitric oxide synthase (tNOS) and level of NO, respectively. NOS promoter L-arginine and inhibitor N^G-Monomethyl-L-arginine inhibited and promoted the killing, respectively, with the elevation and decrease of NOS activity and NO level. The present study further showed that CysJ is the enzyme-producing NO in V. alginolyticus. These results indicate that the cooperative effect of Ala and Gent causes the lowest NO, which plays a key role in Ala-potentiated Gent-mediated killing.

摘要

本研究探讨了丙氨酸 (Ala) 和庆大霉素 (Gent) 对代谢机制的协同作用，通过该机制，外源性 Ala 可增强 Gent 杀死耐抗生素的溶藻弧菌。为了测试这一点，基于 GC-MS 的代谢组学用于表征 Ala、Gent 和两者诱导的代谢特征，确定一氧化氮 (NO) 产生途径是了解代谢机制的最关键线索。Gent、Ala 和两者分别导致总一氧化氮合酶 (tNOS) 和 NO 水平的低、低和最低活性。NOS 启动子 L-精氨酸和抑制剂 N ^G-单甲基-L-精氨酸分别抑制和促进杀灭，随着NOS活性和NO水平的升高和降低。本研究进一步表明，CysJ 是溶藻弧菌中产生酶的 NO 。这些结果表明，Ala 和 Gent 的协同作用导致 NO 最低，这在 Ala 增强的 Gent 介导的杀伤中起关键作用。