Linear osmoregulated periplasmic glucans are encoded by the opgGH locus of Pseudomonas aeruginosa
Linear osmoregulated periplasmic glucans are encoded by the opgGH locus of Pseudomonas aeruginosa
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DOI：
10.1099/mic.0.2007/008953-0
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发表时间：
2007-10-01
期刊：
影响因子：
2.8
通讯作者：
Bohin, Jean-Pierre
中科院分区：
文献类型：
--
作者：
Lequette, Yannick;Rollet, Eglantine;Bohin, Jean-Pierre
渗透调节周质葡聚糖（OPG）是由许多变形菌产生的，对细菌-宿主相互作用非常重要。参与OPG合成的opgG和opgH基因是变形菌基因组中分布最广的基因。另外两个非同源基因，都命名为ndvB，也参与了几个物种的OPG生物合成。铜绿假单胞菌基因组具有两个ORF，PA 5077和PA 5078，分别显示出与假单胞菌的opgH和opgG的相似性，以及一个ORF，PA 1163，类似于苜蓿中华根瘤菌的ndvB。在这里，我们报告说，铜绿假单胞菌PA 14的opgGH基因座参与合成的线性聚合物与β-1，2-连接的葡萄糖残基与几个β-1，6葡萄糖残基支链。琥珀酰残基也取代了该葡萄糖主链。opgGH的转录被高渗透压抑制。低渗透压促进高度结构化的生物膜的形成，但生物膜的发展较慢，生物量的面积减少在高渗透压下。在低渗透压下生长的opgGH突变体的生物膜发育呈现与在高渗透压下生长的野生型生物膜相似的表型。这些结果表明，OPG是重要的低渗透压条件下的生物膜形成。先前的研究表明，铜绿假单胞菌ndvB基因参与了生物膜对抗生素的耐药性。我们已经表明，ndvB不参与此处描述的OPG的生物合成，并且opgGH似乎不参与铜绿假单胞菌PA 14生物膜对抗生素的抗性。
Osmoregulated periplasmic glucans (OPGs) are produced by many proteobacteria and are important for bacterial-host interactions. The opgG and opgH genes involved in the synthesis of OPGs are the most widely distributed genes in proteobacterial genomes. Two other non-homologous genes, both named ndvB, are also involved in OPG biosynthesis in several species. The Pseudomonas aeruginosa genome possesses two ORFs, PA5077 and PA5078, that show similarity to opgH and opgG of Pseudomonas syringae, respectively, and one ORF, PA1163, similar to ndvB of Sinorhizobium meliloti. Here, we report that the opgGH locus of P. aeruginosa PA14 is involved in the synthesis of linear polymers with beta-1,2-linked glucosyl residues branched with a few beta-1,6 glucosyl residues. Succinyl residues also substitute this glucose backbone. Transcription of opgGH is repressed by high osmolarity. Low osmolarity promotes the formation of highly structured biofilms, but biofilm development is slower and the area of biomass is reduced under high osmolarity. Biofilm development of an opgGH mutant grown under low osmolarity presents a similar phenotype to the wild-type biofilm grown under high osmolarity. These results suggest that OPGs are important for biofilm formation under conditions of low osmolarity. A previous study suggested that the P. aeruginosa ndvB gene is involved in the resistance of biofilms to antibiotics. We have shown that ndvB is not involved in the biosynthesis of the OPG described here, and opgGH do not appear to be involved in the resistance of P. aeruginosa PA14 biofilms to antibiotics.