Pseudomonas aeruginosa uses a cyclic-di-GMP-regulated adhesin to reinforce the biofilm extracellular matrix.
Pseudomonas aeruginosa uses a cyclic-di-GMP-regulated adhesin to reinforce the biofilm extracellular matrix.
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DOI：
10.1111/j.1365-2958.2009.06991.x
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发表时间：
2010-02
影响因子：
3.6
通讯作者：
Parsek MR
中科院分区：
文献类型：
--
作者：
Borlee BR;Goldman AD;Murakami K;Samudrala R;Wozniak DJ;Parsek MR
铜绿假单胞菌，囊性纤维化患者的主要病原体，形成耐药生物膜，促进气道的慢性定植。胞外（EPS）基质是生物膜的重要组成部分，为社区提供多种益处。最近的研究表明，第二信使，环二GMP，促进生物膜的形成。在c-di-GMP升高的条件下，对铜绿假单胞菌中特异性表达的因子的分析揭示了涉及生物膜细胞外基质的产生和维持的功能。我们的特点是这些组件之一，编码的PA 4625基因，作为一个假定的粘附素，并指定它的cdrA。CdrA与属于双伴侣分泌系统的细胞外粘附素具有结构相似性。cdrA基因位于一个双基因操纵子中，该操纵子还编码一种推定的外膜转运蛋白CdrB。cdrA基因编码一个220 KDa的蛋白质，该蛋白质被预测为具有β-螺旋结构基序的杆状蛋白质。Western分析表明，CdrA作为220 kDa的前蛋白产生，并在分泌到细胞外培养基中之前加工成150 kDa。我们证明了cdrAB表达在液体培养中是最小的，但在生物膜培养中升高。发现CdrAB表达促进液体培养中生物膜形成和自动聚集。由CdrA介导的聚集依赖于Psl多糖，并且可以通过添加甘露糖（Psl的关键结构组分）来破坏。存在于培养物上清液中的Psl的免疫沉淀导致CdrA的共免疫沉淀，提供了CdrA直接结合Psl的额外证据。cdrA的突变导致生物膜生物量减少，并导致生物膜的形成，表现出降低的结构完整性。Psl特异性凝集素染色表明CdrA将Psl多糖聚合物和/或系链Psl交联到细胞，导致生物膜结构稳定性增加。因此，本研究确定了铜绿假单胞菌EPS基质的关键蛋白质结构组分。
Pseudomonas aeruginosa, the principal pathogen of cystic fibrosis patients, forms antibiotic-resistant biofilms promoting chronic colonization of the airways. The extracellular (EPS) matrix is a crucial component of biofilms that provides the community multiple benefits. Recent work suggests that the secondary messenger, cyclic-di-GMP, promotes biofilm formation. An analysis of factors specifically expressed in P. aeruginosa under conditions of elevated c-di-GMP, revealed functions involved in the production and maintenance of the biofilm extracellular matrix. We have characterized one of these components, encoded by the PA4625 gene, as a putative adhesin and designated it cdrA. CdrA shares structural similarities to extracellular adhesins that belong to two-partner secretion systems. The cdrA gene is in a two gene operon that also encodes a putative outer membrane transporter, CdrB. The cdrA gene encodes a 220 KDa protein that is predicted to be rod-shaped protein harbouring a β-helix structural motif. Western analysis indicates that the CdrA is produced as a 220 kDa proprotein and processed to 150 kDa before secretion into the extracellular medium. We demonstrated that cdrAB expression is minimal in liquid culture, but is elevated in biofilm cultures. CdrAB expression was found to promote biofilm formation and auto-aggregation in liquid culture. Aggregation mediated by CdrA is dependent on the Psl polysaccharide and can be disrupted by adding mannose, a key structural component of Psl. Immunoprecipitation of Psl present in culture supernatants resulted in co-immunoprecipitation of CdrA, providing additional evidence that CdrA directly binds to Psl. A mutation in cdrA caused a decrease in biofilm biomass and resulted in the formation of biofilms exhibiting decreased structural integrity. Psl-specific lectin staining suggests that CdrA either cross-links Psl polysaccharide polymers and/or tethers Psl to the cells, resulting in increased biofilm structural stability. Thus, this study identifies a key protein structural component of the P. aeruginosa EPS matrix.
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DOI：
10.1099/00221287-13-3-572
发表时间：
1955-01-01
期刊：
JOURNAL OF GENERAL MICROBIOLOGY
影响因子：
--
作者：
HOLLOWAY, BW
通讯作者：
HOLLOWAY, BW
影响因子：
3.6
作者：
Danese, PN;Pratt, LA;Kolter, R
通讯作者：
Kolter, R
影响因子：
2.1
作者：
Gjermansen, Morten;Ragas, Paula;Tolker-Nielsen, Tim
通讯作者：
Tolker-Nielsen, Tim
影响因子：
5.6
作者：
Jones, DT
通讯作者：
Jones, DT
影响因子：
3.2
作者：
Friedman, L;Kolter, R
通讯作者：
Kolter, R