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Author Rahman, S.A.; St Hilaire, M.A.; Gronfier, C.; Chang, A.-M.; Santhi, N.; Czeisler, C.A.; Klerman, E.B.; Lockley, S.W.
Title Functional decoupling of melatonin suppression and circadian phase resetting in humans Type Journal Article
Year 2018 Publication The Journal of Physiology Abbreviated Journal J Physiol
Volume 596 Issue 11 Pages 2147-2157
Keywords Human Health
Abstract KEY POINTS: There is assumed to be a monotonic association between melatonin suppression and circadian phase resetting induced by light exposure. We tested the association between melatonin suppression and phase resetting in humans. Sixteen young healthy participants received nocturnal bright light ( approximately 9500 lux) exposure of continuous or intermittent patterns, and different durations ranging from 12 min to 6.5 h. Intermittent exposure patterns showed significant phase shifts with disproportionately less melatonin suppression. Each and every bright light stimulus in an intermittent exposure pattern induced a similar degree of melatonin suppression, but did not appear to cause an equal magnitude of phase shift. These results suggest that phase shifts and melatonin suppression are functionally independent such that one cannot be used as a proxy measure of the other. ABSTRACT: Continuous experimental light exposures show that, in general, the conditions that produce greater melatonin suppression also produce greater phase shift, leading to the assumption that one can be used as a proxy for the other. We tested this association in 16 healthy individuals who participated in a 9-day inpatient protocol by assessing melatonin suppression and phase resetting in response to a nocturnal light exposure (LE) of different patterns: (i) dim-light control (<3 lux; n = 6) or (ii) two 12-min intermittent bright light pulses (IBL) separated by 36 min of darkness ( approximately 9500 lux; n = 10). We compared these results with historical data from additional LE patterns: (i) dim-light control (<3 lux; n = 11); (ii) single continuous bright light exposure of 12 min (n = 9), 1.0 h (n = 10) or 6.5 h (n = 6); or (iii) an IBL light pattern consisting of six 15-min pulses with 1.0 h dim-light recovery intervals between them during a total of 6.5 h (n = 7). All light exposure groups had significantly greater phase-delay shifts than the dim-light control condition (P < 0.0001). While a monotonic association between melatonin suppression and circadian phase shift was observed, intermittent exposure patterns showed significant phase shifts with disproportionately less melatonin suppression. Each and every IBL stimulus induced a similar degree of melatonin suppression, but did not appear to cause an equal magnitude of phase shift. These results suggest unique specificities in how light-induced phase shifts and melatonin suppression are mediated such that one cannot be used as a proxy measure of the other.
Address Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA
Corporate Author Thesis
Publisher Place of Publication Editor
Language (up) English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0022-3751 ISBN Medium
Area Expedition Conference
Notes PMID:29707782 Approved no
Call Number GFZ @ kyba @ Serial 1887
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Author Dimovski, A.M.; Robert, K.A.
Title Artificial light pollution: Shifting spectral wavelengths to mitigate physiological and health consequences in a nocturnal marsupial mammal Type Journal Article
Year 2018 Publication Journal of Experimental Zoology. Part A, Ecological and Integrative Physiology Abbreviated Journal J Exp Zool A Ecol Integr Physiol
Volume 329 Issue 8-9 Pages 497-505
Keywords Animals; Lighting
Abstract The focus of sustainable lighting tends to be on reduced CO2 emissions and cost savings, but not on the wider environmental effects. Ironically, the introduction of energy-efficient lighting, such as light emitting diodes (LEDs), may be having a great impact on the health of wildlife. These white LEDs are generated with a high content of short-wavelength 'blue' light. While light of any kind can suppress melatonin and the physiological processes it regulates, these short wavelengths are potent suppressors of melatonin. Here, we manipulated the spectral composition of LED lights and tested their capacity to mitigate the physiological and health consequences associated with their use. We experimentally investigated the impact of white LEDs (peak wavelength 448 nm; mean irradiance 2.87 W/m(2) ), long-wavelength shifted amber LEDs (peak wavelength 605 nm; mean irradiance 2.00 W/m(2) ), and no lighting (irradiance from sky glow < 0.37 x 10(-3) W/m(2) ), on melatonin production, lipid peroxidation, and circulating antioxidant capacity in the tammar wallaby (Macropus eugenii). Night-time melatonin and oxidative status were determined at baseline and again following 10 weeks exposure to light treatments. White LED exposed wallabies had significantly suppressed nocturnal melatonin compared to no light and amber LED exposed wallabies, while there was no difference in lipid peroxidation. Antioxidant capacity declined from baseline to week 10 under all treatments. These results provide further evidence that short-wavelength light at night is a potent suppressor of nocturnal melatonin. Importantly, we also illustrate that shifting the spectral output to longer wavelengths could mitigate these negative physiological impacts.
Address Department of Ecology, Environment and Evolution, La Trobe University, Melbourne, Australia
Corporate Author Thesis
Publisher Place of Publication Editor
Language (up) English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2471-5638 ISBN Medium
Area Expedition Conference
Notes PMID:29722167 Approved no
Call Number GFZ @ kyba @ Serial 1888
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Author McLay, L.K.; Nagarajan-Radha, V.; Green, M.P.; Jones, T.M.
Title Dim artificial light at night affects mating, reproductive output, and reactive oxygen species in Drosophila melanogaster Type Journal Article
Year 2018 Publication Journal of Experimental Zoology. Part A, Ecological and Integrative Physiology Abbreviated Journal J Exp Zool A Ecol Integr Physiol
Volume 329 Issue 8-9 Pages 419-428
Keywords Animals
Abstract Humans are lighting the night-time environment with ever increasing extent and intensity, resulting in a variety of negative ecological effects in individuals and populations. Effects of light at night on reproductive fitness traits are demonstrated across taxa however, the mechanisms underlying these effects are largely untested. One possible mechanism is that light at night may result in perturbed reactive oxygen species (ROS) and oxidative stress levels. Here, we reared Drosophila melanogaster under either dim (10 lx) light or no light (0 lx) at night for three generations and then compared mating and lifetime oviposition patterns. In a second experiment, we explored whether exposure to light at night treatments resulted in variation in ROS levels in the heads and ovaries of six, 23- and 36-day-old females. We demonstrate that dim light at night affects mating and reproductive output: 10 lx flies courted for longer prior to mating, and female oviposition patterns differed to 0 lx females. ROS levels were lower in the ovaries but not heads, of 10 lx compared with 0 lx females. We suggest that reduced ROS levels may reflect changes in ovarian physiology and cell signaling, which may be related to the differences observed in oviposition patterns. Taken together, our results indicate negative consequences for invertebrates under more stressful, urban, lit conditions and further investigation into the mechanisms driving these changes is warranted to manage invertebrate communities in a brighter future.
Address School of BioSciences, Faculty of Science, The University of Melbourne, Melbourne, Victoria, Australia
Corporate Author Thesis
Publisher Place of Publication Editor
Language (up) English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2471-5638 ISBN Medium
Area Expedition Conference
Notes PMID:29733537 Approved no
Call Number GFZ @ kyba @ Serial 1889
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Author Borck, P.C.; Batista, T.M.; Vettorazzi, J.F.; Soares, G.M.; Lubaczeuski, C.; Guan, D.; Boschero, A.C.; Vieira, E.; Lazar, M.A.; Carneiro, E.M.
Title Nighttime light exposure enhances Rev-erbalpha-targeting microRNAs and contributes to hepatic steatosis Type Journal Article
Year 2018 Publication Metabolism: Clinical and Experimental Abbreviated Journal Metabolism
Volume 85 Issue Pages 250-258
Keywords Animals
Abstract OBJECTIVE: The exposure to artificial light at night (ALAN) disrupts the biological rhythms and has been associated with the development of metabolic syndrome. MicroRNAs (miRNAs) display a critical role in fine-tuning the circadian system and energy metabolism. In this study, we aimed to assess whether altered miRNAs expression in the liver underlies metabolic disorders caused by disrupted biological rhythms. RESULTS: We found that C3H/HePas mice exposed to ALAN developed obesity, and hepatic steatosis, which was paralleled by decreased expression of Rev-erbalpha and up-regulation of its lipogenic targets ACL and FAS in liver. Furthermore, the expression of Rev-erbalpha-targeting miRNAs, miR-140-5p, 185-5p, 326-5p and 328-5p were increased in this group. Consistently, overexpression of these miRNAs in primary hepatocytes reduced Rev-erbalpha expression at the mRNA and protein levels. Importantly, overexpression of Rev-erbalpha-targeting miRNAs increased mRNA levels of Acly and Fasn. CONCLUSION: Thus, altered miRNA profile is an important mechanism underlying the disruption of the peripheral clock caused by exposure to ALAN, which could lead to hepatic steatosis.
Address Obesity and Comorbidities Research Center, Institute of Biology, University of Campinas/UNICAMP, Campinas, SP, Brazil; Department of Structural and Functional Biology, Institute of Biology, University of Campinas/UNICAMP, Campinas, SP, Brazil
Corporate Author Thesis
Publisher Place of Publication Editor
Language (up) English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0026-0495 ISBN Medium
Area Expedition Conference
Notes PMID:29751019 Approved no
Call Number GFZ @ kyba @ Serial 1891
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Author Gaydecki, P.
Title Automated moth flight analysis in the vicinity of artificial light Type Journal Article
Year 2018 Publication Bulletin of Entomological Research Abbreviated Journal Bull Entomol Res
Volume 109 Issue 1 Pages 127-140
Keywords Instrumentation; Animals
Abstract Instrumentation and software for the automated analysis of insect flight trajectories is described, intended for quantifying the behavioural dynamics of moths in the vicinity of artificial light. For its time, this moth imaging system was relatively advanced and revealed hitherto undocumented insights into moth flight behaviour. The illumination source comprised a 125 W mercury vapour light, operating in the visible and near ultraviolet wavelengths, mounted on top of a mobile telescopic mast at heights of 5 and 7.1 m, depending upon the experiment. Moths were imaged in early September, at night and in field conditions, using a ground level video camera with associated optics including a heated steering mirror, wide angle lens and an electronic image intensifier. Moth flight coordinates were recorded at a rate of 50 images per second (fields) and transferred to a computer using a light pen (the only non-automated operation in the processing sequence). Software extracted ground speed vectors and, by instantaneous subtraction of wind speed data supplied by fast-response anemometers, the airspeed vectors. Accumulated density profiles of the track data revealed that moths spend most of their time at a radius of between 40 and 50 cm from the source, and rarely fly directly above it, from close range. Furthermore, the proportion of insects caught by the trap as a proportion of the number influenced by the light (and within the field of view of the camera) was very low; of 1600 individual tracks recorded over five nights, a total of only 12 were caught. Although trap efficiency is strongly dependent on trap height, time of night, season, moonlight and weather, the data analysis confirmed that moths do not exhibit straightforward positive phototaxis. In general, trajectory patterns become more complex with reduced distance from the illumination, with higher recorded values of speeds and angular velocities. However, these characteristics are further qualified by the direction of travel of the insect; the highest accelerations tended to occur when the insect was at close range, but moving away from the source. Rather than manifesting a simple positive phototaxis, the trajectories were suggestive of disorientation. Based on the data and the complex behavioural response, mathematical models were developed that described ideal density distribution in calm air and light wind speed conditions. The models did not offer a physiological hypothesis regarding the behavioural changes, but rather were tools for quantification and prediction. Since the time that the system was developed, instrumentation, computers and software have advanced considerably, allowing much more to be achieved at a small fraction of the original cost. Nevertheless, the analytical tools remain useful for automated trajectory analysis of airborne insects.
Address School of Electrical and Electronic Engineering, University of Manchester,Manchester M13 9PL,UK
Corporate Author Thesis
Publisher Place of Publication Editor
Language (up) English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0007-4853 ISBN Medium
Area Expedition Conference
Notes PMID:29745349 Approved no
Call Number GFZ @ kyba @ Serial 1895
Permanent link to this record