Chemokinesis

Definition

A chemically induced, non-directional change in the speed, frequency, or amplitude of cell or organismal movement, lacking the vectorial component that characterizes chemotaxis. In chemokinesis, the chemical stimulus modulates motility parameters—such as swimming velocity or turning rate—without providing a directional cue, resulting in random or undirected displacement that may increase or decrease overall dispersal.

Etymology

Greek kinesis (movement) with chemo- (chemical)

Example

In the mosquito Anopheles gambiae, sperm stored in the spermatheca exhibit chemokinesis in response to seminal fluid peptides, increasing flagellar beat frequency to maintain motility without directional swimming toward an egg; similarly, hemocytes of many insects show chemokinetic activation by bacterial fragments, elevating random crawling speed during encapsulation responses.

Related Terms

• Chemotaxis
• Kinesis
• orthokinesis
• klinokinesis
• sperm motility
• hemocyte activation

Usage Notes

Distinguished from chemotaxis by the absence of a concentration gradient providing directional information; chemokinesis alters how fast or how often cells move, not where they move. In arthropod studies, the term is sometimes loosely applied to any chemical-modulated locomotion, but strict usage reserves it for non-oriented responses. Checkerboard assays and computer-assisted cell tracking are standard for quantifying chemokinesis, as simple transwell migration cannot separate it from chemotaxis.