Center for Systems Microbiology, Technical University of Denmark, Lyngby, Denmark.
Department of Environmental Protection, Estación Experimental del Zaidín, Consejo Superior de Investigaciones Científicas (CSIC), Granada, Spain.
Microbiology (Reading). 2011 Aug;157(Pt 8):2257-2265. doi: 10.1099/mic.0.047787-0. Epub 2011 May 20.
A number of genetic determinants required for bacterial colonization of solid surfaces and biofilm formation have been identified in different micro-organisms. There are fewer accounts of mutations that favour the transition to a sessile mode of life. Here we report the isolation of random transposon Pseudomonas putida KT2440 mutants showing increased biofilm formation, and the detailed characterization of one of them. This mutant exhibits a complex phenotype, including altered colony morphology, increased production of extracellular polymeric substances and enhanced swarming motility, along with the formation of denser and more complex biofilms than the parental strain. Sequence analysis revealed that the pleiotropic phenotype exhibited by the mutant resulted from the accumulation of two mutations: a transposon insertion, which disrupted a predicted outer membrane lipoprotein, and a point mutation in lapG, a gene involved in the turnover of the large adhesin LapA. The contribution of each alteration to the phenotype and the possibility that prolonged sessile growth results in the selection of hyperadherent mutants are discussed.
已经在不同微生物中鉴定出了许多用于细菌定殖固体表面和生物膜形成的遗传决定因素。关于有利于向静止生活方式转变的突变的报道较少。在这里，我们报告了随机转座子假单胞菌属 KT2440 突变体的分离，这些突变体显示出增强的生物膜形成能力，并对其中之一进行了详细表征。该突变体表现出复杂的表型，包括改变的菌落形态、增加的细胞外聚合物的产生和增强的泳动运动，以及形成比亲本菌株更密集和更复杂的生物膜。序列分析表明，突变体表现出的多效表型是由于两个突变的积累所致：转座子插入，破坏了一个预测的外膜脂蛋白，以及 lapG 中的点突变，该基因参与大粘附素 LapA 的周转。讨论了每个改变对表型的贡献以及延长静止生长是否会导致选择高粘附突变体的可能性。
