DataSheet_1_Piscirickettsia salmonis Produces a N-Acetyl-L-Homoserine Lactone as a Bacterial Quorum Sensing System-Related Molecule.docx

Piscirickettsia salmonis is the etiological agent of piscirickettsiosis, the most prevalent disease in salmonid species in Chilean salmonids farms. Many bacteria produce N-acyl-homoserine lactones (AHLs) as a quorum-sensing signal molecule to regulate gene expression in a cell density-dependent manner, and thus modulate physiological characteristics and several bacterial mechanisms. In this study, a fluorescent biosensor system method and gas chromatography-tandem mass spectrometry (GC/MS) were combined to detect AHLs produced by P. salmonis. These analyses revealed an emitted fluorescence signal when the biosensor P. putida EL106 (RPL4cep) was co-cultured with both, P. salmonis LF-89 type strain and an EM-90-like strain Ps007, respectively. Furthermore, the production of an AHL-type molecule was confirmed by GC/MS by both P. salmonis strains, which identified the presence of a N-acetyl-L-homoserine Lactone in the supernatant extract. However, It is suggested that an alternate pathway could synthesizes AHLs, which should be address in future experiments in order to elucidate this important bacterial process. To the best of our knowledge, the present report is the first to describe the type of AHLs produced by P. salmonis.

杀鲑立克次体（Piscirickettsia salmonis）是杀鲑立克次体病的病原菌，该病是智利鲑鱼养殖场中鲑形目鱼类最流行的病害。许多细菌会产生N-酰基高丝氨酸内酯（N-acyl-homoserine lactones, AHLs）作为群体感应信号分子，以细胞密度依赖的方式调控基因表达，进而调节细菌的生理特性与多种生理机制。本研究结合荧光生物传感系统方法与气相色谱-串联质谱（gas chromatography-tandem mass spectrometry, GC/MS），对杀鲑立克次体产生的AHLs进行检测。分析结果显示，当生物传感菌株恶臭假单胞菌EL106（RPL4cep）分别与杀鲑立克次体LF-89模式菌株及EM-90类菌株Ps007共培养时，均可检测到荧光信号。此外，两种杀鲑立克次体菌株产生的AHL类分子经GC/MS验证得以确认，其上清提取物中检出了N-乙酰-L-高丝氨酸内酯。不过，研究提示可能存在一条替代途径参与AHLs的合成，该问题需在后续实验中进一步阐明，以明确这一重要的细菌生理过程。据我们所知，本报告首次报道了杀鲑立克次体所产生的AHLs类型。