Pan Somalisa, Underhill Simon A M, Hamm Christopher W, Stover Mylissa A, Butler Daxton R, Shults Crystal A, Manjarrez Jacob R, Cabeen Matthew T
Department of Microbiology, Oklahoma State University, Stillwater, Oklahoma, USA.
Department of Biochemistry and Microbiology, OSU Center for Health Sciences, Tulsa, Oklahoma, USA.
mSphere. 2024 Apr 23;9(4):e0078623. doi: 10.1128/msphere.00786-23. Epub 2024 Mar 19.
is a ubiquitous bacterium and a notorious opportunistic pathogen that forms biofilm structures in response to many environmental cues. Biofilm formation includes attachment to surfaces and the production of the exopolysaccharide Pel, which is present in both the PAO1 and PA14 laboratory strains of . Biofilms help protect bacterial cells from host defenses and antibiotics and abet infection. The carbon source used by the cells also influences biofilm, but these effects have not been deeply studied. We show here that glycerol, which can be liberated from host surfactants during infection, encourages surface attachment and magnifies colony morphology differences. We find that glycerol kinase is important but not essential for glycerol utilization and relatively unimportant for biofilm behaviors. Among downstream enzymes predicted to take part in glycerol utilization, Edd stood out as being important for glycerol utilization and for enhanced biofilm phenotypes in the presence of glycerol. Thus, gluconeogenesis and catabolism of anabolically produced glucose appear to impact not only the utilization of glycerol but also glycerol-stimulated biofilm phenotypes. Finally, waxworm moth larvae and nematode infection models reveal that interruption of the Entner-Doudoroff pathway, but not abrogation of glycerol phosphorylation, unexpectedly increases lethality in both acute and chronic infections, even while stimulating a stronger immune response by .IMPORTANCE, the ubiquitous environmental bacterium and human pathogen, forms multicellular communities known as biofilms in response to various stimuli. We find that glycerol, a common carbon source that bacteria can use for energy and biosynthesis, encourages biofilm behaviors such as surface attachment and colony wrinkling by . Glycerol can be derived from surfactants that are present in the human lungs, a common infection site. Glycerol-stimulated biofilm phenotypes do not depend on phosphorylation of glycerol but are surprisingly impacted by a glucose breakdown pathway, suggesting that it is glycerol utilization, and not its mere presence or cellular import, that stimulates biofilm phenotypes. Moreover, the same mutations that block glycerol-stimulated biofilm phenotypes also impact virulence in both acute and chronic animal models. Notably, a glucose-breakdown mutant (Δ) counteracts biofilm phenotypes but shows enhanced virulence and stimulates a stronger immune response in .
是一种普遍存在的细菌，也是一种臭名昭著的机会致病菌，它会根据许多环境信号形成生物膜结构。生物膜形成包括附着于表面以及产生胞外多糖Pel，PAO1和PA14实验室菌株中均存在这种多糖。生物膜有助于保护细菌细胞免受宿主防御和抗生素的影响，并助长感染。细胞使用的碳源也会影响生物膜，但这些影响尚未得到深入研究。我们在此表明，甘油在感染期间可从宿主表面活性剂中释放出来，它会促进表面附着并放大菌落形态差异。我们发现甘油激酶对于甘油利用很重要但并非必不可少，对于生物膜行为相对不重要。在预测参与甘油利用的下游酶中，Edd对于甘油利用以及在甘油存在下增强生物膜表型显得很重要。因此，糖异生作用和合成代谢产生的葡萄糖的分解代谢似乎不仅影响甘油的利用，还影响甘油刺激的生物膜表型。最后，蜡虫蛾幼虫和线虫感染模型表明，Entner-Doudoroff途径的中断而非甘油磷酸化的废除，出乎意料地增加了急性和慢性感染中的致死率，即使同时刺激了更强的免疫反应。重要的是，这种普遍存在的环境细菌和人类病原体，会根据各种刺激形成称为生物膜的多细胞群落。我们发现，甘油是细菌可用于能量和生物合成的常见碳源，它会促进诸如表面附着和菌落起皱等生物膜行为。甘油可源自人类肺部（一个常见的感染部位）中存在的表面活性剂。甘油刺激的生物膜表型不依赖于甘油的磷酸化，但令人惊讶地受到葡萄糖分解途径的影响，这表明是甘油的利用而非其单纯的存在或细胞导入刺激了生物膜表型。此外，阻断甘油刺激的生物膜表型的相同突变也会影响急性和慢性动物模型中的毒力。值得注意的是，葡萄糖分解突变体（Δ）可抵消生物膜表型，但显示出增强的毒力并在中刺激更强的免疫反应。
