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从假单胞菌M18株(Pseudomonas sp.M18)中,克隆了las系统的双元组分lasI和lasR基因,它们的编码产物属于LuxI-LuxR调控因子.运用同源重组技术,分别构建lasI和lasR基因的染色体失活突变株,与野生型菌株相比,抗生素藤黄绿脓菌素(Plt)和吩嗪-1-羧酸(PCA)的产量均分别提高了4~5倍和2~3倍.在lasI和lasR突变株的反式互补实验中,两种抗生素的产量回复到野生型水平.pltA′-′lacZ和phzA′-′lacZ翻译融合的测定结果进一步证明lasI和lasR的编码产物对Plt和PCA生物合成基因簇具有负调控作用.las系统正调控细菌的群集运动,在lasI和lasR的失活突变株中,细菌的群集运动能力消失.对lasI和lasR突变株和野生型的生长曲线的研究发现,lasI和lasR基因的编码产物对细菌的生长具有抑制作用.结果表明,las系统作为整体调控因子的编码基因,参了与细胞内多种生物活动的调控作用.
The lasI and lasR genes of the las system were cloned from Pseudomonas sp.M18 and their coding products belonged to the LuxI-LuxR regulatory factor.Using homologous recombination technology, lasI and lasR genes were constructed respectively Compared with the wild-type strain, the yield of the antibiotics Garcinia cambogia Pichia and the phenazine-1-carboxylic acid (PCA) increased 4 ~ 5 and 2 ~ 3 times in the lasI and lasR mutant trans-complementation experiments, the two antibiotics yield returned to the wild-type level .pltA ’-’ lacZ and phzA ’-’ lacZ translational fusion assay results further evidence of lasI and lasR encoding The product has a negative regulatory effect on Plt and PCA biosynthetic gene cluster.The las system is regulating the cluster movement of bacteria and the ability of bacteria to cluster movement disappears in lasI and lasR inactivating mutants.It is suggested that lasI and lasR mutants and wild type The results showed that the lasI and lasR genes could inhibit the growth of bacteria.The results showed that las system, as a regulator of whole regulators, is involved in the regulation of various biological activities in cells.