title: Cycles of circadian illuminance are sufficient to entrain and maintain circadian locomotor rhythms in Drosophila.
abstract: Light at night disrupts the circadian clock and causes serious health problems in the modern world. Here, we show that newly developed four-package light-emitting diodes (LEDs) can provide harmless lighting at night. To quantify the effects of light on the circadian clock, we employed the concept of circadian illuminance (CIL). CIL represents the amount of light weighted toward the wavelengths to which the circadian clock is most sensitive, whereas visual illuminance (VIL) represents the total amount of visible light. Exposure to 12 h:12 h cycles of white LED light with high and low CIL values but a constant VIL value (conditions hereafter referred to as CH/CL) can entrain behavioral and molecular circadian rhythms in flies. Moreover, flies re-entrain to phase shift in the CH/CL cycle. Core-clock proteins are required for the rhythmic behaviors seen with this LED lighting scheme. Taken together, this study provides a guide for designing healthful white LED lights for use at night, and proposes the use of the CIL value for estimating the harmful effects of any light source on organismal health.
authors.affiliation: Department of Brain Science, Ajou University School of Medicine, 164 Worldcup-ro, Suwon, 16499, Republic of Korea.|Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, 164 Worldcup-ro, Suwon, 16499, Republic of Korea.
authors.forename: Eunjoo
authors.initials: E
authors.lastname: Cho
authors.affiliation: Department of Chemistry, Kookmin University, Seoul, 136-702, Republic of Korea.
authors.forename: Ji Hye
authors.initials: JH
authors.lastname: Oh
authors.affiliation: Department of Brain Science, Ajou University School of Medicine, 164 Worldcup-ro, Suwon, 16499, Republic of Korea.|Neuroscience Graduate Program, BK21 Plus Program, Department of Biomedical Sciences, Ajou University School of Medicine, 164 Worldcup-ro, Suwon, 16499, Republic of Korea.
authors.forename: Euna
authors.initials: E
authors.lastname: Lee
authors.affiliation: Department of Chemistry, Kookmin University, Seoul, 136-702, Republic of Korea.
authors.forename: Young Rag
authors.initials: YR
authors.lastname: Do
authors.affiliation: Department of Brain Science, Ajou University School of Medicine, 164 Worldcup-ro, Suwon, 16499, Republic of Korea.|Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, 164 Worldcup-ro, Suwon, 16499, Republic of Korea.|Neuroscience Graduate Program, BK21 Plus Program, Department of Biomedical Sciences, Ajou University School of Medicine, 164 Worldcup-ro, Suwon, 16499, Republic of Korea.
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Kim
mesh_terms: D000818:Animals; D056926:CLOCK Proteins / Q000378:metabolism; D057906:Circadian Clocks / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D004330:Drosophila / Q000378:metabolism / Q000502:physiology*; D008027:Light; D009043:Motor Activity / Q000502:physiology*
chemical_list: D056926:CLOCK Proteins