Catabolism of Nucleic Acids by a Cystic Fibrosis Pseudomonas aeruginosa Isolate: An Adaptive Pathway to Cystic Fibrosis Sputum Environment
Catabolism of Nucleic Acids by a Cystic Fibrosis Pseudomonas aeruginosa Isolate: An Adaptive Pathway to Cystic Fibrosis Sputum Environment
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DOI：
10.3389/fmicb.2019.01199
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发表时间：
2019-05-31
影响因子：
5.2
通讯作者：
Paulsen, Ian T.
中科院分区：
文献类型：
--
作者：
Kumar, Sheemal Shanista;Penesyan, Anahit;Paulsen, Ian T.
铜绿假单胞菌是囊性纤维化（CF）患者发病和死亡的主要原因。我们对铜绿假单胞菌CF分离株进行了Biolog表型微阵列检测，以研究其与铜绿假单胞菌实验室菌株PAO 1和PA 14相比的分解代谢能力。一株PASS 4表现出不寻常的表型，仅对腺苷和肌苷显示出强呼吸作用。进一步的测试表明，PASS 4可以在DNA作为唯一碳源的情况下生长，其生物量产量高于PAO 1。这表明PASS 4特异性地适应于代谢细胞外DNA，细胞外DNA是CF肺中以高浓度存在的底物。PASS 4和PAO 1的转录组学和蛋白质组学分析当以DNA作为唯一碳源生长时，鉴定了一组上调的基因，包括毒力和宿主适应基因。PASS 4不能利用N-乙酰基-D-葡糖胺，当我们选择能够在这种碳源上生长的PASS 4突变体时，它们也显示出分解代谢广泛的其他碳源的能力的增加。突变体的基因组测序显示，它们都含有purK基因内的突变，编码从头嘌呤生物合成途径中的关键蛋白。这表明PASS 4是一个嘌呤营养缺陷型。在2 mM腺苷存在下的生长测定和PASS 4与完整purK基因的互补证实了这一结论。嘌呤营养缺陷型可能代表了一种可行的微生物策略，以适应DNA丰富的环境，如CF肺。
Pseudomonas aeruginosa is a major cause of morbidity and mortality in patients with cystic fibrosis (CF). We undertook Biolog Phenotype Microarray testing of P. aeruginosa CF isolates to investigate their catabolic capabilities compared to P. aeruginosa laboratory strains PAO1 and PA14. One strain, PASS4, displayed an unusual phenotype, only showing strong respiration on adenosine and inosine. Further testing indicated that PASS4 could grow on DNA as a sole carbon source, with a higher biomass production than PAO1. This suggested that PASS4 was specifically adapted to metabolize extracellular DNA, a substrate present at high concentrations in the CF lung. Transcriptomic and proteomic profiling of PASS4 and PAO1 when grown with DNA as a sole carbon source identified a set of upregulated genes, including virulence and host-adaptation genes. PASS4 was unable to utilize N-Acetyl-D-glucosamine, and when we selected PASS4 mutants able to grow on this carbon source, they also displayed a gain in ability to catabolize a broad range of other carbon sources. Genome sequencing of the mutants revealed they all contained mutations within the purK gene, encoding a key protein in the de novo purine biosynthesis pathway. This suggested that PASS4 was a purine auxotroph. Growth assays in the presence of 2 mM adenosine and the complementation of PASS4 with an intact purK gene confirmed this conclusion. Purine auxotrophy may represent a viable microbial strategy for adaptation to DNA-rich environments such as the CF lung.