Light-induced behavioral responses (;phototaxis') in prokaryotes
Related Experiment Video
Updated: Aug 15, 2026

Observation of Photobehavior in Chlamydomonas reinhardtii
Published on: May 6, 2022
Judith P Armitage1, Klaas J Hellingwerf
1Department of Biochemistry, Microbiology Unit, University of Oxford, Oxford, OX1 3QU, UK, armitage@bioch.ox. ac.uk.
Abstract:
Light-induced sensory responses are among the oldest scientific observations on bacterial behavior. Various types of response have been characterized physiologically in detail. However, the molecular basis of this type of response is only slowly emerging. In many of these systems photosynthetic pigments absorb the light. This then generates a signal via electron transport, feeding into a canonical chemotaxis signal transduction pathway. Nevertheless, several examples have been identified in which dedicated photoreceptor proteins do play a role. The intrinsic complexity of some of these signal transduction systems is overwhelming, in part because of the significant apparent redundancy. The genomics information that is now available for several model organisms (in particular Rhodobacter sphaeroides and Synechocystis sp. PCC6803) facilitates obtaining an increasingly detailed view of the molecular basis of the partial reactions that jointly form the basis of this type of elementary behavioral response.
Related Concept Videos
Channel Rhodopsins
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
Photoreceptors and Plant Responses to Light
Chemotaxis in E. coli
Protein Dynamics in Living Cells
Fluorescent recovery after photobleaching (FRAP) is a fluorescent-protein-based detection technique used to quantify protein movement rates within the cell. This method exposes a small portion of the cell to an intense laser beam. The laser beam causes permanent photobleaching of the fluorophore-tagged proteins in the exposed region. As the bleached...
Photoreceptors and Visual Pathways
Biological Clocks and Seasonal Responses

