Summary and remarks

This paper addresses the motion of a bacterium with a single polar flagellum swimming in a liquid medium close to a rigid surface. The unusual character-istics that appear only when a bacterial cell swims close to a surface were qualitatively explained as the result of the fluid-dynamic interaction between the cell and the surface. These characteristics possibly explain the behavior of the bacterial taxis around surfaces, which may be animate or inanimate surfaces, or the forma-tion of bio-films. A simulation suggests that the asymmetrical characteristics help the bacterial cell efficiently cover a searching area (Magariyama 2005). When a cell approaches a surface with its flagellum oriented toward the sur-face, the cell may have a higher tendency to attach to the surface.

 

 n most observations of microorganisms, including bacteria, in a liquid medium, the medium is sealed between a glass slide and a cover slip. The studies presented here have revealed that the microorganism motion might be strongly influenced by the existence of such boundaries. Microorganisms are considered examples of micro-machines. Their exis-tence provides confirmation that such tiny micro-machines could be con-structed without violating natural laws. From an engineering point of view, learning from microorganisms is essential to understanding the mechanism of swimming, propulsion, sensing, guidance, control, and structures suitable for the micro-scale realm. The mechanism of asymmetrical motion revealed here could be applied to build such tiny machines. This work was partly supported by JSPS