Adaptive behaviors of planktonic Pseudomonas aeruginosa in response to the surface-deposited dead siblings

作者：Yuan, Shuo; Qi, Meng; Peng, Qingmei; Huang, Gui; Liu, Jun; Xu, Zhenbo; Gong, Xiangjun^*; Zhang, Guangzhao

来源：Colloids and Surfaces B: Biointerfaces , 2021, 197: 111408.

DOI：10.1016/j.colsurfb.2020.111408

• Dead bacteria
• Digital holographic microscopy
• Pseudomonas aeruginosa
• Bacterial interactions

In this study, the 3D motion behaviors and the underlying adaptation mechanism of planktonic Pseudomonas aeruginosa (PAO1) in response to the deposited dead siblings nearby were explored. Utilizing a real-time 3D tracking technique, digital holographic microscopy (DHM), we demonstrate that planktonic cells near the surface covered with dead siblings have a lower density and a reduced 3D velocity compared with those upon viable ones. As a sign of chemosensory responses, bacteria swimming near the dead siblings exhibit increase in frequency of the 'flick' motion. Transcriptomic analysis by RNA-seq reveals an upregulated expression of dgcM and dgcE inhibited the movement of PAO1, accompanied by increased transcriptional levels of the virulence factor-related genes hcp1, clpV1, and vgrG1. Moreover, the decrease in L-glutamate and the increase in succinic acid in the metabolites of the dead bacteria layer promote the dispersion of planktonic bacteria. As a result, the dead siblings on a surface inhibit the bacterial accumulation and activate the adaptive defensive responses of planktonic PAO1 in the vicinity.