Oral Biosciences, Faculty of Dentistry, The University of Hong Kong, Hong Kong City, Hong Kong.
Mol Oral Microbiol. 2013 Feb;28(1):54-69. doi: 10.1111/omi.12006. Epub 2012 Oct 12.
Elucidation of bacterial and fungal interactions in multispecies biofilms will have major impacts on understanding the pathophysiology of infections. The objectives of this study were to (i) evaluate the effect of Pseudomonas aeruginosa lipopolysaccharide (LPS) on Candida albicans hyphal development and transcriptional regulation, (ii) investigate protein expression during biofilm formation, and (iii) propose likely molecular mechanisms for these interactions. The effect of LPS on C. albicans biofilms was assessed by XTT-reduction and growth curve assays, light microscopy, scanning electron microscopy (SEM), and confocal laser scanning microscopy (CLSM). Changes in candidal hypha-specific genes (HSGs) and transcription factor EFG1 expression were assessed by real-time polymerase chain reaction and two-dimensional gel electrophoresis, respectively. Proteome changes were examined by mass spectrometry. Both metabolic activities and growth rates of LPS-treated C. albicans biofilms were significantly lower (P < 0.05). There were higher proportions of budding yeasts in test biofilms compared with the controls. SEM and CLSM further confirmed these data. Significantly upregulated HSGs (at 48 h) and EFG1 (up to 48 h) were noted in the test biofilms (P < 0.05) but cAMP levels remained unaffected. Proteomic analysis showed suppression of candidal septicolysin-like protein, potential reductase-flavodoxin fragment, serine hydroxymethyltransferase, hypothetical proteins Cao19.10301(ATP7), CaO19.4716(GDH1), CaO19.11135(PGK1), CaO19.9877(HNT1) by P. aeruginosa LPS. Our data imply that bacterial LPS inhibit C. albicans biofilm formation and hyphal development. The P. aeruginosa LPS likely target glycolysis-associated mechanisms during candidal filamentation.
阐明多物种生物膜中的细菌和真菌相互作用将对理解感染的病理生理学产生重大影响。本研究的目的是：(i) 评估铜绿假单胞菌脂多糖 (LPS) 对白色念珠菌菌丝发育和转录调控的影响，(ii) 研究生物膜形成过程中的蛋白质表达，(iii) 提出这些相互作用的可能分子机制。通过 XTT 还原和生长曲线测定、相差显微镜、扫描电子显微镜 (SEM) 和共聚焦激光扫描显微镜 (CLSM) 评估 LPS 对 C. albicans 生物膜的影响。通过实时聚合酶链反应和二维凝胶电泳分别评估候选菌丝特异性基因 (HSG) 和转录因子 EFG1 的表达变化。通过质谱法检查蛋白质组变化。用 LPS 处理的 C. albicans 生物膜的代谢活性和生长速率均显著降低 (P < 0.05)。与对照相比，测试生物膜中的出芽酵母比例更高。SEM 和 CLSM 进一步证实了这些数据。在测试生物膜中观察到 HSGs (48 h 时) 和 EFG1 (高达 48 h) 的表达显著上调 (P < 0.05)，但 cAMP 水平不受影响。蛋白质组学分析表明，铜绿假单胞菌 LPS 抑制白色念珠菌的裂殖酶样蛋白、潜在的还原酶-黄素蛋白片段、丝氨酸羟甲基转移酶、假定蛋白 Cao19.10301(ATP7)、CaO19.4716(GDH1)、CaO19.11135(PGK1)、CaO19.9877(HNT1)。我们的数据表明，细菌 LPS 抑制 C. albicans 生物膜形成和菌丝发育。铜绿假单胞菌 LPS 可能靶向白色念珠菌菌丝形成过程中的糖酵解相关机制。
