Quorum sensing, bacterial cell-to-cell communication via small signaling molecules regulates virulence in many bacterial pathogens, and is a promising target for antivirulence therapy, which may inhibit virulence rather than cell growth and division. Herein, Bacillus strains capable of degrading QS molecules from freshwater environments were screened as potential aquaculture probiotics. A total of 34 Bacillus strains were isolated. Strain T-1 was selected with “H” streaking and double layer agar plate methods using Chromabacterium violaceum ATCC12472 as reporter, and eventually identified as Bacillus licheniformis based on biochemical and molecular identification. Quorum quenching by T-1 was confirmed using C. violaceum CV026. T-1 was non-hemolytic in vitro. In biocontrol experiments, T-1 reduced the pathogenicity of Aeromonas hydrophila cb15 in zebrafish co-injected intraperitoneally with both strains, achieving a relative percentage survival of 70%. Determination and analysis of the T-1 draft genome using the Illumina Hiseq 2500 platform identified the quorum quenching gene ytnP, encoding an acyl-homoserine lactone metallo-β-lactamase, as a potential QS quencher in T-1. In conclusion, B. licheniformis T-1 could be a safe and effective quorum quenching bacterium for protecting hosts against pathogenic bacterial infections in aquaculture.

中文翻译：

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Quorum淬灭细菌地衣芽孢杆菌T-1保护斑马鱼免受嗜水气单胞菌感染。

群体感应，通过小信号分子的细菌细胞间通讯调节了许多细菌病原体中的毒力，是抗毒力治疗的有希望的目标，它可以抑制毒力而不是抑制细胞的生长和分裂。在此，筛选能够降解淡水环境中QS分子的芽孢杆菌菌株作为潜在的水产养殖益生菌。总共分离出34株芽孢杆菌。T菌株T-1用紫花色杆菌ATCC12472作为报告基因，采用“ H”划线和双层琼脂平板法筛选，最终根据生化和分子鉴定鉴定为地衣芽孢杆菌。使用紫花衣藻证实了通过T-1进行的群体淬灭CV026。T-1在体外非溶血性。在生物防治实验中，T-1降低了与两种菌株腹膜内共同注射的斑马鱼中嗜水气单胞菌cb15的致病性，相对存活率达到70％。使用Illumina Hiseq 2500平台对T-1草图基因组进行测定和分析，确定了群体猝灭基因ytnP，它编码酰基高丝氨酸内酯金属β-内酰胺酶，是T-1中潜在的QS猝灭剂。总之，地衣芽孢杆菌T-1可能是一种安全有效的群体猝灭细菌，可以保护宿主免受水产养殖中的病原菌感染。