Bacterial Chemotaxis

During the 17th century, the advent of the light microscope allowed scientists to observe “tiny particles” that were proposed to be living due to their seemingly purposeful motion.[3] It was only in the 19th century when directed bacterial movements were first characterised by Wilhelm Pfeffer.[3] Pfeffer’s work described the ability of bacteria to navigate through complex environments, in response to changes in temperature (thermotaxis), osmolarity (osmotaxis), light (phototaxis) and chemical substrates (chemotaxis).[3]

Bacterial chemotaxis is a regulated response that involves the processing of chemical substrates as input signals, into physical movements that result in bacterial motility.[2] This response allows for bacteria to selectively move along chemical gradients[4] (Fig 1), directing them towards substances that are favourable to their survival, and away from noxious substances.[5] Therefore, chemotaxis confers an important survival advantage to bacteria, particularly in their natural, non-mixed environment in which chemical gradients exist.[4,5]