contribution of cell elongation to the biofilm formation of pseudomonas aeruginosa during anaerobic respiration贡献的细胞伸长铜绿假单胞菌在厌氧呼吸的生物膜的形成.pdfVIP

Contribution of Cell Elongation to the Biofilm Formation of Pseudomonas aeruginosa during Anaerobic Respiration 1. 1. 1 1,2,3 Mi Young Yoon , Kang-Mu Lee , Yongjin Park , Sang Sun Yoon * 1 Department of Microbiology, Yonsei University College of Medicine, Seoul, Republic of Korea, 2 Brain Korea 21 Project for Medical Sciences, Yonsei University College of Medicine, Seoul, Republic of Korea, 3 Research Institute of Bacterial Resistance, Yonsei University College of Medicine, Seoul, Republic of Korea Abstract Pseudomonas aeruginosa, a gram-negative bacterium of clinical importance, forms more robust biofilm during anaerobic respiration, a mode of growth presumed to occur in abnormally thickened mucus layer lining the cystic fibrosis (CF) patient airway. However, molecular basis behind this anaerobiosis-triggered robust biofilm formation is not clearly defined yet. Here, we identified a morphological change naturally accompanied by anaerobic respiration in P. aeruginosa and investigated its effect on the biofilm formation in vitro. A standard laboratory strain, PAO1 was highly elongated during anaerobic respiration compared with bacteria grown aerobically. Microscopic analysis demonstrated that cell elongation likely occurred as a consequence of defective cell division. Cell elongation was dependent on the presence of nitrite reductase (NIR) that reduces nitrite (NO22) to nitric oxide (NO) and was repressed in PAO1 in the presence of carboxy-PTIO, a NO antagonist, demonstrating that cell elongation involves a process to respond to NO, a spontaneous byproduct of the anaerobic respiration. Importantly, the non-elongated NIR-deficient mutant failed to form biofilm, while a mut