Quimiokinesis

Quimiokinesis, commonly known in English as chemokinesis, is a non-directional motility response to a chemical stimulus in which the rate or pattern of movement of an organism changes without a directed movement toward or away from the chemical source. In contrast to chemotaxis, chemokinesis does not involve the organism moving up or down a chemical gradient; instead, the presence or concentration of the chemical modulates overall activity, such as speed or the frequency of turning.

Chemokinetic responses can be classified as positive, where motility increases, or negative, where motility decreases. The underlying mechanisms typically involve chemoreceptors and intracellular signaling pathways that adjust the activity of the cell’s motility machinery, such as flagellar rotation or cytoskeletal dynamics, without creating a directional bias toward a stimulus source.

Organisms in which chemokinesis has been studied include certain bacteria, unicellular eukaryotes, and some animal cells. In bacteria, exposure to nutrients or repellents can alter run and tumble statistics without stable orientation toward the stimulus. In protozoa and some cultured mammalian cells, chemical cues can modify locomotion speed or protrusive activity, especially in uniform or non-gradient environments.

Measurement and interpretation rely on tracking movement under uniform chemical exposure to assess changes in speed, turning frequency, and net displacement, and then distinguishing these from true chemotaxis by analyzing behavior in gradients. The concept aids understanding of how organisms optimize foraging, tissue navigation, and collective movement when directional cues are weak or absent.

See also: chemotaxis, motility, chemokine signaling.