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Author Fonken, L.K.; Aubrecht, T.G.; Melendez-Fernandez, O.H.; Weil, Z.M.; Nelson, R.J.
Title Dim light at night disrupts molecular circadian rhythms and increases body weight Type Journal Article
Year 2013 Publication Journal of Biological Rhythms Abbreviated Journal J Biol Rhythms
Volume 28 Issue 4 Pages 262-271
Keywords Animals; Blood Glucose/metabolism; Body Weight/*physiology; CLOCK Proteins/biosynthesis/genetics; Circadian Rhythm/*physiology; Corticosterone/metabolism; Feeding Behavior/physiology; Immunohistochemistry; Light; *Lighting; Male; Mice; Motor Activity; Polymerase Chain Reaction; Suprachiasmatic Nucleus/metabolism/physiology; clock genes; feeding rhythm; light pollution; obesity
Abstract With the exception of high latitudes, life has evolved under bright days and dark nights. Most organisms have developed endogenously driven circadian rhythms that are synchronized to this daily light/dark cycle. In recent years, humans have shifted away from the naturally occurring solar light cycle in favor of artificial and sometimes irregular light schedules produced by electric lighting. Exposure to unnatural light cycles is increasingly associated with obesity and metabolic syndrome; however, the means by which environmental lighting alters metabolism are poorly understood. Thus, we exposed mice to dim light at night and investigated changes in the circadian system and metabolism. Here we report that exposure to ecologically relevant levels of dim (5 lux) light at night altered core circadian clock rhythms in the hypothalamus at both the gene and protein level. Circadian rhythms in clock expression persisted during light at night; however, the amplitude of Per1 and Per2 rhythms was attenuated in the hypothalamus. Circadian oscillations were also altered in peripheral tissues critical for metabolic regulation. Exposure to dimly illuminated, as compared to dark, nights decreased the rhythmic expression in all but one of the core circadian clock genes assessed in the liver. Additionally, mice exposed to dim light at night attenuated Rev-Erb expression in the liver and adipose tissue. Changes in the circadian clock were associated with temporal alterations in feeding behavior and increased weight gain. These results are significant because they provide evidence that mild changes in environmental lighting can alter circadian and metabolic function. Detailed analysis of temporal changes induced by nighttime light exposure may provide insight into the onset and progression of obesity and metabolic syndrome, as well as other disorders involving sleep and circadian rhythm disruption.
Address Department of Neuroscience and Institute for Behavioral Medicine Research, Wexner Medical Center, The Ohio State University, Columbus, OH 43210, USA. fonken.1@osu.edu
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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 (up)
Area Expedition Conference
Notes PMID:23929553; PMCID:PMC4033305 Approved no
Call Number IDA @ john @ Serial 28
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Author Dominoni, D.; Quetting, M.; Partecke, J.
Title Artificial light at night advances avian reproductive physiology Type Journal Article
Year 2013 Publication Proceedings. Biological Sciences / The Royal Society Abbreviated Journal Proc Biol Sci
Volume 280 Issue 1756 Pages 20123017
Keywords Animals; *Lighting; Male; Molting; Photoperiod; Reproduction/*physiology; Singing; Songbirds/*physiology; Testis/anatomy & histology; Testosterone/blood; Trees
Abstract Artificial light at night is a rapidly increasing phenomenon and it is presumed to have global implications. Light at night has been associated with health problems in humans as a consequence of altered biological rhythms. Effects on wild animals have been less investigated, but light at night has often been assumed to affect seasonal cycles of urban dwellers. Using light loggers attached to free-living European blackbirds (Turdus merula), we first measured light intensity at night which forest and city birds are subjected to in the wild. Then we used these measurements to test for the effect of light at night on timing of reproductive physiology. Captive city and forest blackbirds were exposed to either dark nights or very low light intensities at night (0.3 lux). Birds exposed to light at night developed their reproductive system up to one month earlier, and also moulted earlier, than birds kept under dark nights. Furthermore, city birds responded differently than forest individuals to the light at night treatment, suggesting that urbanization can alter the physiological phenotype of songbirds. Our results emphasize the impact of human-induced lighting on the ecology of millions of animals living in cities and call for an understanding of the fitness consequences of light pollution.
Address Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Radolfzell 78315, Germany. ddominoni@orn.mpg.de
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0962-8452 ISBN Medium (up)
Area Expedition Conference
Notes PMID:23407836; PMCID:PMC3574380 Approved no
Call Number IDA @ john @ Serial 50
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Author Kempenaers, B.; Borgstrom, P.; Loes, P.; Schlicht, E.; Valcu, M.
Title Artificial night lighting affects dawn song, extra-pair siring success, and lay date in songbirds Type Journal Article
Year 2010 Publication Current Biology : CB Abbreviated Journal Curr Biol
Volume 20 Issue 19 Pages 1735-1739
Keywords Animals; Environmental Pollution; Female; Light; *Lighting; Male; *Reproduction; Sexual Behavior, Animal/*physiology; Songbirds/*physiology; Time Factors; *Vocalization, Animal
Abstract Associated with a continued global increase in urbanization, anthropogenic light pollution is an important problem. However, our understanding of the ecological consequences of light pollution is limited. We investigated effects of artificial night lighting on dawn song in five common forest-breeding songbirds. In four species, males near street lights started singing significantly earlier at dawn than males elsewhere in the forest, and this effect was stronger in naturally earlier-singing species. We compared reproductive behavior of blue tits breeding in edge territories with and without street lights to that of blue tits breeding in central territories over a 7 year period. Under the influence of street lights, females started egg laying on average 1.5 days earlier. Males occupying edge territories with street lights were twice as successful in obtaining extra-pair mates than their close neighbors or than males occupying central forest territories. Artificial night lighting affected both age classes but had a stronger effect on yearling males. Our findings indicate that light pollution has substantial effects on the timing of reproductive behavior and on individual mating patterns. It may have important evolutionary consequences by changing the information embedded in previously reliable quality-indicator traits.
Address Department of Behavioural Ecology and Evolutionary Genetics, Max Planck Institute for Ornithology, Eberhard-Gwinner-Strasse, 82319 Seewiesen, Germany. b.kempenaers@orn.mpg.de
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0960-9822 ISBN Medium (up)
Area Expedition Conference
Notes PMID:20850324 Approved no
Call Number IDA @ john @ Serial 51
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Author Rockhill, A.P.; DePerno, C.S.; Powell, R.A.
Title The effect of illumination and time of day on movements of bobcats (Lynx rufus) Type Journal Article
Year 2013 Publication PloS one Abbreviated Journal PLoS One
Volume 8 Issue 7 Pages e69213
Keywords Animals; Female; *Lighting; Lynx/*physiology; Male; Moon; Movement/*physiology; North Carolina; Time Factors; Wetlands
Abstract Understanding behavioral changes of prey and predators based on lunar illumination provides insight into important life history, behavioral ecology, and survival information. The objectives of this research were to determine if bobcat movement rates differed by period of day (dark, moon, crepuscular, day), lunar illumination (<10%, 10 – <50%, 50 – <90%, >90%), and moon phase (new, full). Bobcats had high movement rates during crepuscular and day periods and low movement rates during dark periods with highest nighttime rates at 10-<50% lunar illumination. Bobcats had highest movement rates during daytime when nighttime illumination was low (new moon) and higher movement rates during nighttime when lunar illumination was high (full moon). The behaviors we observed are consistent with prey availability being affected by light level and by limited vision by bobcats during darkness.
Address Fisheries, Wildlife, and Conservation Biology, North Carolina State University, Raleigh, North Carolina, USA. aimee_rockhill@ncsu.edu
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-6203 ISBN Medium (up)
Area Expedition Conference
Notes PMID:23861963; PMCID:PMC3704646 Approved no
Call Number IDA @ john @ Serial 84
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Author Evans, J.A.; Carter, S.N.; Freeman, D.A.; Gorman, M.R.
Title Dim nighttime illumination alters photoperiodic responses of hamsters through the intergeniculate leaflet and other photic pathways Type Journal Article
Year 2012 Publication Neuroscience Abbreviated Journal Neuroscience
Volume 202 Issue Pages 300-308
Keywords Animals; Biological Clocks/physiology; Circadian Rhythm/physiology; Cricetinae; Darkness; Data Interpretation, Statistical; Geniculate Bodies/*physiology; *Lighting; Male; Motor Activity/physiology; Phodopus; *Photoperiod; Visual Pathways/*physiology
Abstract In mammals, light entrains the central pacemaker within the suprachiasmatic nucleus (SCN) through both a direct neuronal projection from the retina and an indirect projection from the intergeniculate leaflet (IGL) of the thalamus. Although light comparable in intensity to moonlight is minimally effective at resetting the phase of the circadian clock, dimly lit and completely dark nights are nevertheless perceived differentially by the circadian system, even when nighttime illumination is below putative thresholds for phase resetting. Under a variety of experimental paradigms, dim nighttime illumination exerts effects that may be characterized as enhancing the plasticity of circadian entrainment. For example, relative to completely dark nights, dimly lit nights accelerate development of photoperiodic responses of Siberian hamsters transferred from summer to winter day lengths. Here we assess the neural pathways underlying this response by testing whether IGL lesions eliminate the effects of dim nighttime illumination under short day lengths. Consistent with previous work, dimly lit nights facilitated the expansion of activity duration under short day lengths. Ablation of the IGL, moreover, did not influence photoperiodic responses in animals held under completely dark nights. However, among animals that were provided dimly lit nights, IGL lesions prevented the short-day typical expansion of activity duration as well as the seasonally appropriate gonadal regression and reduction in body weight. Thus, the present data indicate that the IGL plays a central role in mediating the facilitative effects of dim nighttime illumination under short day lengths, but in the absence of the IGL, dim light at night influences photoperiodic responses through residual photic pathways.
Address Department of Psychology, University of California, San Diego, La Jolla, CA, USA. jevans@msm.edu
Corporate Author Thesis
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0306-4522 ISBN Medium (up)
Area Expedition Conference
Notes PMID:22155265; PMCID:PMC3578228 Approved no
Call Number IDA @ john @ Serial 87
Permanent link to this record