Isonitrile-functionalized tyrosine modulates swarming motility and quorum sensing in Pseudomonas aeruginosa
Isonitrile-functionalized tyrosine modulates swarming motility and quorum sensing in Pseudomonas aeruginosa
复制标题
DOI：
10.1016/j.micpath.2018.12.001
复制
发表时间：
2019-02-01
影响因子：
3.8
通讯作者：
Qaisar, Uzma
中科院分区：
文献类型：
--
作者：
Asif, Azka;Iftikhar, Anam;Qaisar, Uzma
由pvc操纵子pvcABCD合成的paucumarin是一种调节铜绿假单胞菌生物膜形成的铁结合分子，但其在细菌发病中的直接作用有待进一步研究。pvcA合成异腈功能化酪氨酸（IFT）， IFT由pvcB、pvcC和pvcD基因编码的蛋白转化为成熟的paucumarin。ppvcb在MPAO1中的中断导致IFT的积累，因为它不能转化为成熟分子。MPAO1 pvcB突变体（PW4832）表现出增强的群体运动性，而与携带pvcB的质粒pLL2互补则降低了群体运动性。与亲本菌株相比，PW4832的rhIA表达水平和鼠李糖脂产量均有所提高。pvcABCD的正调节因子ptxR在PW4832中过表达，导致IFT积累更多，rhlA表达水平进一步升高。与MPAO1相比，群体感应系统转录激活因子lasR和HA以及合成酶基因Iasi和rhlI的表达在PW4832中增强，PQS积累也增强。外源添加IFT能提高铜绿假单胞菌鼠李糖脂的产量，而不添加绿皮素。这些结果表明，IFT通过直接提高鼠李糖脂的产生或间接调节群体感应系统来增强铜绿假单胞菌的群体运动。这是首次在铜绿假单胞菌中发现IFT的独立功能。
Paerucumarin synthesized by pvc operon pvcABCD is an iron binding molecule which modulates biofilm formation in Pseudomonas aeruginosa but its direct function in bacterial pathogenesis needs further investigation. pvcA synthesizes isonitrile functionalized tyrosine (IFT) which is converted to mature paerucumarin by the proteins encoded by pvcB, pvcC and pvcD genes. Interruption of pvcB in MPAO1 resulted in accumulation of IFT as it cannot be converted to mature molecule. The MPAO1 pvcB mutant (PW4832) showed enhanced swarming motility, while complementation with plasmid pLL2 carrying pvcB reduced swarming motility. Enhanced levels of rhIA expression and rhamnolipid production were observed in PW4832 compared to the parent strain. Overexpression of ptxR, the positive regulator of pvcABCD, in PW4832 caused accumulation of more IFT and further elevated the level of rhlA expression. Expression of the quorum sensing system transcriptional activators lasR and HA as well as the synthase genes Iasi and rhlI, was enhanced in PW4832 compared to MPAO1, as was PQS accumulation. Exogenously added IFT, but not paerucumarin, enhanced the production of rhamnolipids in P. aeruginosa. These results suggest that IFT enhances swarming motility in P. aeruginosa either directly by enhancing rhamnolipid production or indirectly through modulation of the quorum sensing systems. This is the first report assigning an independent function to IFT in P. aeruginosa.