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Author Flores, D.E.F.L.; Oda, G.A.
Title Novel Light/Dark Regimens with Minimum Light Promote Circadian Disruption: Simulations with a Model Oscillator Type Journal Article
Year 2018 Publication Journal of Biological Rhythms Abbreviated Journal J Biol Rhythms
Volume in press Issue Pages
Keywords Animals
Abstract (up) Artificial lab manipulation of LD cycles has enabled simulations of the disruptive conditions found in modern human societies, such as jet-lag, night-work and light at night. New techniques using animal models have been developed, and these can greatly improve our understanding of circadian disruption. Some of these techniques, such as in vivo bioluminescence assays, require minimum external light. This requirement is challenging because the usual lighting protocols applied in circadian desynchronization experiments rely on considerable light input. Here, we present a novel LD regimen that can disrupt circadian rhythms with little light per day, based on computer simulations of a model limit-cycle oscillator. The model predicts that a single light pulse per day has the potential to disturb rhythmicity when pulse times are randomly distributed within an interval. Counterintuitively, the rhythm still preserves an underlying 24-h periodicity when this interval is as large as 14 h, indicating that day/night cues are still detectable. Only when pulses are spread throughout the whole 24-h day does the rhythm lose any day-to-day period correlation. In addition, the model also reveals that stronger pulses of brighter light should exacerbate the disrupting effects. We propose the use of this LD schedule-which would be compatible with the requirements of in vivo bioluminescence assays-to help understand circadian disruption and associated illnesses.
Address Instituto de Biociencias, Universidade de Sao Paulo, Sao Paulo, SP, Brazil
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0748-7304 ISBN Medium
Area Expedition Conference
Notes PMID:30595077 Approved no
Call Number GFZ @ kyba @ Serial 2146
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Author Lundberg, L.; Sienkiewicz, Z.; Anthony, D.C.; Broom, K.A.
Title Effects of 50 Hz magnetic fields on circadian rhythm control in mice Type Journal Article
Year 2019 Publication Bioelectromagnetics Abbreviated Journal Bioelectromagnetics
Volume 40 Issue 4 Pages 250-259
Keywords Animals; mouse models; magnetic fields
Abstract (up) Artificial light and power frequency magnetic fields are ubiquitous in the built environment. Light is a potent zeitgeber but it is unclear whether power frequency magnetic fields can influence circadian rhythm control. To study this possibility, 8-12-week-old male C57BL/6J mice were exposed for 30 min starting at zeitgeber time 14 (ZT14, 2 h into the dark period of the day) to 50 Hz magnetic fields at 580 muT using a pair of Helmholtz coils and/or a blue LED light at 700 lux or neither. Our experiments revealed an acute adrenal response to blue light, in terms of increased adrenal per1 gene expression, increased serum corticosterone levels, increased time spent sleeping, and decreased locomotor activity (in all cases, P < 0.0001) compared to an unexposed control group. There appeared to be no modulating effect of the magnetic fields on the response to light, and there was also no effect of the magnetic fields alone (in both cases, P > 0.05) except for a decrease in locomotor activity (P < 0.03). Gene expression of the cryptochromes cry1 and cry2 in the adrenals, liver, and hippocampus was also not affected by exposures (in all cases, P > 0.05). In conclusion, these results suggest that 50 Hz magnetic fields do not significantly affect the acute light response to a degree that can be detected in the adrenal response.
Address Public Health England, Chilton, United Kingdom;
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0197-8462 ISBN Medium
Area Expedition Conference
Notes PMID:30945762 Approved no
Call Number GFZ @ kyba @ Serial 2289
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Author Dananay, K.L.; Benard, M.F.
Title Artificial light at night decreases metamorphic duration and juvenile growth in a widespread amphibian Type Journal Article
Year 2018 Publication Proceedings of the Royal Society B: Biological Sciences Abbreviated Journal Proc. R. Soc. B
Volume 285 Issue 1882 Pages 20180367
Keywords Animals
Abstract (up) Artificial light at night (ALAN) affects over 20% of the earth's surface and is estimated to increase 6% per year. Most studies of ALAN have focused on a single mechanism or life stage. We tested for indirect and direct ALAN effects that occurred by altering American toads' (Anaxyrus americanus) ecological interactions or by altering toad development and growth, respectively. We conducted an experiment over two life stages using outdoor mesocosms and indoor terraria. In the first phase, the presence of ALAN reduced metamorphic duration and periphyton biomass. The effects of ALAN appeared to be mediated through direct effects on toad development, and we found no evidence for indirect effects of ALAN acting through altered ecological interactions or colonization. In the second phase, post-metamorphic toad growth was reduced by 15% in the ALAN treatment. Juvenile-stage ALAN also affected toad activity: in natural light, toads retreated into leaf litter at night whereas ALAN toads did not change behaviour. Carry-over effects of ALAN were also present; juvenile toads that had been exposed to larval ALAN exhibited marginally increased activity. In this time frame and system, our experiments suggested ALAN's effects act primarily through direct effects, rather than indirect effects, and can persist across life stages.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0962-8452 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 1951
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Author Peregrym, M., Kónya E. P., & Vasyliuk, O.
Title The impact of artificial light at night (ALAN) on the National Nature Parks, Biosphere and Naturе Reserves of the Steppe Zone and Crimean Mountains within Ukraine Type Journal Article
Year 2018 Publication Palaearctic Grasslands Abbreviated Journal
Volume Issue Pages
Keywords Skyglow; Conservation
Abstract (up) Artificial light at night (ALAN) and sky glow are a recognized anthropogenic pressure, but the consequences of this pressure on protected areas within Ukraine are unclear. This research attempted to estimate the level of light pollution on the protected territories of the National Nature Parks (NNPs), Biosphere and Nature Reserves in the Steppe Zone and Crimea Mountains of Ukraine. Kmz layers of

these protected territories and the New World Atlas of Artificial Sky Brightness, through Google Earth Pro, were used to calculate the level of artificial sky brightness for 15 NNPs, three Biosphere Reserves and 10 Nature Reserves. The results show that even some of the most protected areas within the Steppe Zone and Crimean Mountains are impacted by ALAN. Of the studied protected areas 44.2% have a natural dark night sky, 40.1% have artificial brightness ranging between 8 and 16%, and the remainder (15.7%) are polluted with an artificial brightness greater than 16%. Areas with light pollution greater than 16% are often situated near big cities or industrial centers. It was noted that light pollution levels were not taken into account during the creation of any protected areas within Ukraine.
Address
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Publisher Place of Publication Editor
Language Summary Language Original Title
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ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ intern @ Serial 2310
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Author Grunst, M.L.; Raap, T.; Grunst, A.S.; Pinxten, R.; Parenteau, C.; Angelier, F.; Eens, M.
Title Early-life exposure to artificial light at night elevates physiological stress in free-living songbirds Type Journal Article
Year 2020 Publication Environmental Pollution Abbreviated Journal Environmental Pollution
Volume Issue Pages in press
Keywords Animals
Abstract (up) Artificial light at night (ALAN) can disrupt adaptive patterns of physiology and behavior that promote high fitness, resulting in physiological stress and elevation of steroid glucocorticoids (corticosterone, CORT in birds). Elevated CORT may have particularly profound effects early in life, with the potential for enduring effects that persist into adulthood. Research on the consequences of early-life exposure to ALAN remains limited, especially outside of the laboratory, and the effects of early-life light exposure on CORT concentrations in wild nestling birds remain to be elucidated. We used an experimental setup to test the hypothesis that ALAN elevates CORT concentrations in developing free-living birds, by exposing nestling great tits (Parus major) to ALAN inside nest boxes. We measured CORT in feathers grown over the timeframe of the experiment (7 nights), such that CORT concentrations represent an integrative metric of hormone release over the period of nocturnal light exposure, and of development. We also assessed the relationships between feather CORT concentrations, body condition, nestling size rank and fledging success. In addition, we evaluated the relationship between feather CORT concentrations and telomere length. Nestlings exposed to ALAN had higher feather CORT concentrations than control nestlings, and nestlings in poorer body condition and smaller brood members also had higher CORT. On the other hand, telomere length, fledging success, and recruitment rate were not significantly associated with light exposure or feather CORT concentrations. Results indicate that exposure to ALAN elevates CORT concentrations in nestlings, which may reflect physiological stress. In addition, the organizational effects of CORT are known to be substantial. Thus, despite the lack of effect on telomere length and survivorship, elevated CORT concentrations in nestlings exposed to ALAN may have subsequent impacts on later-life fitness and stress sensitivity.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0269-7491 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2796
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