Initiation of biofilm formation by Pseudomonas aeruginosa 57RP correlates with emergence of hyperpiliated and highly adherent phenotypic variants deficient in swimming, swarming, and twitching motilities
Initiation of biofilm formation by Pseudomonas aeruginosa 57RP correlates with emergence of hyperpiliated and highly adherent phenotypic variants deficient in swimming, swarming, and twitching motilities
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DOI：
10.1128/jb.183.4.1195-1204.2001
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发表时间：
2001-02-01
影响因子：
3.2
通讯作者：
Villemur, R
中科院分区：
文献类型：
--
作者：
Déziel, E;Comeau, Y;Villemur, R
铜绿假单胞菌是一种普遍存在的环境细菌，能够在表面形成生物膜作为一种生存策略。它表现出各种各样的竞争/毒力因素，如三种类型的运动：鞭毛介导的游泳，鞭毛介导的蜂群和IV型菌毛介导的抽搐。细菌在不断变化的环境条件下生存的一种经常使用的策略是通过一种称为阶段变异的机制来创造一个表型异质性的种群。在本报告中，我们描述了当P. aeruginosa 57RP作为生物膜或静态液体培养物培养时自发出现的小而粗糙的菌落的表型变异的特征。这些小菌落(S)变异产生丰富的IV型菌毛，表现出游泳、群集和抽搐运动的缺陷，并在趋化性方面受损。它们在液体培养中也会自动聚集，并迅速形成牢固粘附的生物膜。相比之下，大菌落变体（亲本形式）粘附性差，在液体培养中均匀分散，并且产生很少的极性被。对S变异体的进一步分析表明，在多种其他表型性状上存在差异，包括pyocyanin和pyoverdine的产量增加以及弹性酶活性降低。在适当的生长条件下，每种表型的细胞以相当高的频率切换到另一种表型。我们得出结论，这些S变体是由相变化引起的，当P. aeruginosa 57RP作为生物膜或静态液体培养时，这些S变体被选择性地富集。我们提出，阶段变化确保了表型形式的预先存在，这些表型形式很好地适应了一旦环境条件有利，就会启动生物膜的形成。
Pseudomonas aeruginosa is a ubiquitous environmental bacterium capable of forming biofilms on surfaces as a survival strategy. It exhibits a large variety of competition/virulence factors, such as three types of motilities: flagellum-mediated swimming, flagellum-mediated swarming, and type IV pilus-mediated twitching. A strategy frequently used by bacteria to survive changing environmental conditions is to create a phenotypically heterogeneous population by a mechanism called phase variation. In this report, we describe the characterization of phenotypic variants farming small, rough colonies that spontaneously emerged when P. aeruginosa 57RP was cultivated as a biofilm or in static liquid cultures. These small-colony (S) variants produced abundant type IV fimbriae, displayed defective swimming, swarming, and twitching motilities, and were impaired in chemotaxis. They also autoaggregated in liquid cultures and rapidly initiated the formation of strongly adherent biofilms. In contrast, the large-colony variant (parent form) was poorly adherent, homogeneously dispersed in liquid cultures, and produced scant polar fimbriae. Further analysis of the S variants demonstrated differences in a variety of other phenotypic traits, including increased production of pyocyanin and pyoverdine and reduced elastase activity. Under appropriate growth conditions, cells of each phenotype switched to the other phenotype at a fairly high frequency. We conclude that these S variants resulted from phase variation and were selectively enriched when P. aeruginosa 57RP was grown as a biofilm or in static liquid cultures. We propose that phase variation ensures the prior presence of phenotypic forms well adapted to initiate the formation of a biofilm as soon as environmental conditions are favorable.