Ultradian and circadian rhythms of phototaxis in chlamydomonas reinhardii.

ABSTRACT: We investigated phototactic and circadian rhythmicity in Chlamydomonas reinhardii under photoautotrophic (HSM) and photoorganotrophic (HSA) conditions to explore the influence of metabolic context on rhythmic behavior. Cultures were grown under controlled conditions (LD 12:12, 28 °C). Phototaxis was monitored using an automated multi-channel system that continuously recorded light transmission changes associated with photoaccumulation. Cell density and chlorophyll a were also quantified. Organisms incubated in continuous dim light showed a robust free-running circadian rhythm (∼24 h) with phase-dependent responses to prior light-dark entrainment, with the maximum rate of phototaxis occurring during the subjective day. The phototaxis rhythm could also be initiated by a decrease in li

SUBMITTER: Jenkins HA 

PROVIDER: S-EPMC12664618 | biostudies-literature | 2025 Dec

REPOSITORIES: biostudies-literature