Surface rigidity change of Escherichia coli after filamentous bacteriophage infection.
In this study, the feasibility using atomic force microscopy (AFM) to study the interaction between bacteriophages (phages) and bacteria in situ was demonstrated here. Filamentous phage M13 specifically infects the male Escherichia coli, which expresses F-pili. After infection, E. coli become fragile and grows at a slower rate. AFM provides a powerful tool for investigating these changes in a near-physiological environment. Using high-resolution AFM in phosphate-buffered saline, the damage to the lipopolysaccharide (LPS) layer on the outer membrane of the M13 phage-infected E. coli was observed. The membrane became smoother and more featureless compared to those that were not infected. Besides, the force-distance (f-d) curves were measured to reveal the surface rigidity change in E. coli after M13 phage infection. The effective spring constant and Young's modulus of E. coli decreased after M13 phage infection. Furthermore, the AFM tip was pressed against E. coli to study the response of E. coli under load before and after M13 phage infection. The results showed that after infection E. coli became less rigid and the membrane was also damaged. However, the stiffness changes, including the spring constant and Young's modulus of E. coli, are negligible after M13 phage infection compared with those in previous reports, which may be one of the reasons that E. coli still can maintain its viability after filamentous phage infection.
Department of Materials Science and Engineering, National Tsing-Hua University, Hsinchu, Taiwan.
Yi-Yang
YY
Chen
Chien-Chen
CC
Wu
Jye-Lin
JL
Hsu
Hwei-Ling
HL
Peng
Hwan-You
HY
Chang
Tri-Rung
TR
Yew
D017104:Bacteriophage M13 / Q000378:metabolism*; D001703:Biophysics / Q000379:methods; D004867:Equipment Design; D004926:Escherichia coli / Q000378:metabolism* / Q000821:virology*; D049452:Green Fluorescent Proteins / Q000378:metabolism; D057927:Hydrophobic and Hydrophilic Interactions; D017912:Inovirus / Q000737:chemistry*; D008070:Lipopolysaccharides / Q000737:chemistry* / Q000378:metabolism; D018625:Microscopy, Atomic Force / Q000379:methods; D008856:Microscopy, Fluorescence / Q000379:methods; D008954:Models, Biological; D013499:Surface Properties
D008070:Lipopolysaccharides; D049452:Green Fluorescent Proteins