A Cause for Difference between Forward and Backward Swimming Speeds of Vibrio alginolyticus

Abstract

The difference between forward and backward swimming speeds has been observed for Vibrio alginolyticus by use of high-intensity dark-field microscopy. The reason that causes the difference is not clear at present. There are some possible reasons we may take into account ; the deformation of a flagellum which is caused by the fluid force exerting on the flagellum, the hydrodynamic interaction between a cell and a slide and the changes in rotational speed of a flagellar motor . In order to investigate the reason for the difference, we measure cell body rotation rates simultaneously with swimming speeds of a cell swimming forwards and backwards . The results show that the difference is mainly caused by the variation in the rotation rates of the cell body at least when the cell moves straightly.