How bacteria move without flagella

Abstract

Movement is a fundamental attribute of all living organisms. Many bacteria swim freely in a fluid with a rotation of flagella filament. On the other hand, some tiny organisms have developed several varieties of cell motility without flagella. These mysterious movements are widespread in bacteria, and have been very attractive to many researchers for long time. But it had remained unclear how bacteria move without flagella, and what is the machinery for cell propulsion. Recent advance on the visualization techniques of optical microscopy provides us dynamic behaviors of molecular machineries at a single cellular level in detail, and the current understanding of this field have dramatically jumped in the last 10-20 years. In this review, I would like to introduce our recent study about a surprising new world of biological movements in the smallest life forms such as Spider-man like motion by the repeated cycles of extension and retraction, a caterpillar like motion by the surface flow along cell membrane, and a corkscrew like motion by mechanical drilling in high viscous environments.