Pseudomonas aeruginosa GacA, a factor in multihost virulence, is also essential for biofilm formation
Pseudomonas aeruginosa GacA, a factor in multihost virulence, is also essential for biofilm formation
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DOI：
10.1046/j.1365-2958.2001.02469.x
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发表时间：
2001-06-01
影响因子：
3.6
通讯作者：
Storey, DG
中科院分区：
文献类型：
--
作者：
Parkins, MD;Ceri, H;Storey, DG
我们研究了GacA/GacS双组分调节系统的反应调节剂GacA在铜绿假单胞菌生物膜形成中的潜在作用。当gacA在菌株PA 14中被破坏时，相对于野生型PA 14，导致生物膜形成能力降低10倍。然而，在PA 14 gacA（-）的促生长速率方面没有观察到显著差异。在多拷贝载体pUCP-gacA上提供反式gacA消除了生物膜形成缺陷。对PA 14 gacA（-）形成的生物膜进行扫描电子显微镜检查，发现弥散的细胞簇未能聚集成小菌落，这意味着生物膜发育或表面易位存在缺陷。运动性测定显示PA 14 gacA（-）抽搐或游泳能力没有降低，表明生物膜形成的缺陷不依赖于鞭毛介导的附着和皮利的固体表面移位。类似地进行自诱导物和藻酸盐生物测定，并且没有观察到生产水平的差异，表明这不仅仅是对群体感应或藻酸盐生产的上游效应。抗生素敏感性分析表明，相对于PA 14野生型，PA 14 gacA（-）生物膜对一系列抗生素的抗性中度降低。本研究确定GacA作为铜绿假单胞菌生物被膜形成的一个新的和独立的调控元件。
We have investigated a potential role for GacA, the response regulator of the GacA/GacS two-component regulatory system, in Pseudomonas aeruginosa biofilm formation. When gacA was disrupted in strain PA14, a 10-fold reduction in biofilm formation capacity resulted relative to wild-type PA14. However, no significant difference was observed in the planktonic growth rate of PA14 gacA(-). Providing gacA in trans on the multicopy vector pUCP-gacA abrogated the biofilm formation defect. Scanning electron microscopy of biofilms formed by PA14 gacA(-) revealed diffuse clusters of cells that failed to aggregate into microcolonies, implying a deficit in biofilm development or surface translocation. Motility assays revealed no decrease in PA14 gacA(-) twitching or swimming abilities, indicating that the defect in biofilm formation is independent of flagellar-mediated attachment and solid surface translocation by pili. Autoinducer and alginate bioassays were performed similarly, and no difference in production levels was observed, indicating that this is not merely an upstream effect on either quorum sensing or alginate production. Antibiotic susceptibility profiling demonstrated that PA14 gacA(-) biofilms have moderately decreased resistance to a range of antibiotics relative to PA14 wild type. This study establishes GacA as a new and independent regulatory element in P. aeruginosa biofilm formation.