Three-dimensional Bacterial Motions Near a Surface Investigated by Digital Holographic Microscopy: Effect of Surface Stiffness.
Three-dimensional Bacterial Motions Near a Surface Investigated by Digital Holographic Microscopy: Effect of Surface Stiffness.
复制标题
DOI：
10.1021/acs.langmuir.9b02103
复制
发表时间：
2019-08
期刊：
影响因子：
--
通讯作者：
Qingmei Peng;Xin Zhou;Zhi Wang;Qingyi Xie;Chunfeng Ma;Guangzhao Zhang;Xiangjun Gong
中科院分区：
文献类型：
--
作者：
Qingmei Peng;Xin Zhou;Zhi Wang;Qingyi Xie;Chunfeng Ma;Guangzhao Zhang;Xiangjun Gong
Surface stiffness plays a critical role in bacterial adhesion but the mechanism is unclear since the bacterial motion before adhesion is overlooked. Herein, the three-dimensional (3D) motions of Escherichia coli (E. coli) and Pseudonomas. sp nov 776 onto poly(dimethylsiloxane) (PDMS) surfaces with varying stiffness before adhering were monitored by digital holographic microscopy (DHM). As the Young's modulus (E) of PDMS surface decreases from 278.1 to 3.4 MPa, the adhered E. coli and Pseudonomas. sp decrease in number by 40.4 and 34.9 % respectively. Atomic force microscopy (AFM) measurements show that the adhesion force of bacteria to the surface declines with the decreased surface stiffness. In contrast, a non-tumbling mutant of adhered E. coli (HCB1414 with adaptive function being partially deficient) decreases much less (by 18.4 %). On the other hand, the tumble frequency (Ft) of E. coli HCB1 and flick frequency (Ff) of Pseudomonas sp. increase as the surface stiffness decreases, and the motion bias (Bθ) of Pseudomonas sp. also increases. These facts clearly indicate that the bacteria have adapted responses to the surface stiffness. RNA-sequencing (RNA-seq) reveals that the downregulated Cph2 and CsrA as well as the upregulated GcvA of swimming E. coli HCB1 in bulk near the softer surface promote the bacterial motility.
