title: Regulation of the cyanobacterial circadian clock by electrochemically controlled extracellular electron transfer.
abstract: There is growing awareness that circadian clocks are closely related to the intracellular redox state across a range of species. As the redox state is determined by the exchange of the redox species, electrochemically controlled extracellular electron transfer (EC-EET), a process in which intracellular electrons are exchanged with extracellular electrodes, is a promising approach for the external regulation of circadian clocks. Herein, we discuss whether the circadian clock can be regulated by EC-EET using the cyanobacterium Synechococcus elongatus PCC7942 as a model system. In vivo monitoring of chlorophyll fluorescence revealed that the redox state of the plastoquionone pool could be controlled with EC-EET by simply changing the electrode potential. As a result, the endogenous circadian clock of S. elongatus cells was successfully entrained through periodically modulated EC-EET by emulating the natural light/dark cycle, even under constant illumination conditions. This is the first example of regulating the biological clock by electrochemistry.
authors.affiliation: Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656 (Japan).
authors.forename: Yue
authors.initials: Y
authors.lastname: Lu
authors.forename: Koichi
authors.initials: K
authors.lastname: Nishio
authors.forename: Shoichi
authors.initials: S
authors.lastname: Matsuda
authors.forename: Yuki
authors.initials: Y
authors.lastname: Toshima
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ito
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Konno
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Ishihara
authors.forename: Souichiro
authors.initials: S
authors.lastname: Kato
authors.forename: Kazuhito
authors.initials: K
authors.lastname: Hashimoto
authors.forename: Shuji
authors.initials: S
authors.lastname: Nakanishi
mesh_terms: D002734:Chlorophyll / Q000737:chemistry / Q000378:metabolism; D057906:Circadian Clocks / Q000502:physiology*; D004579:Electron Transport; D004583:Electrons; D008027:Light; D010084:Oxidation-Reduction; D010971:Plastoquinone / Q000737:chemistry; D046940:Synechococcus / Q000378:metabolism*
chemical_list: D002734:Chlorophyll; D010971:Plastoquinone
keywords: circadian clock; cyanobacteria; electrochemistry; electron transfer