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Author Kim, Y.J.; Kim, H.M.; Kim, H.M.; Jeong, B.R.; Lee, H.-J.; Kim, H.-J.; Hwang, S.J.
Title Ice plant growth and phytochemical concentrations are affected by light quality and intensity of monochromatic light-emitting diodes Type Journal Article
Year 2018 Publication Horticulture, Environment, and Biotechnology Abbreviated Journal Hortic. Environ. Biotechnol.
Volume 59 Issue 4 Pages 529-536
Keywords Plants
Abstract The ice plant (Mesembryanthemum crystallinum L.), widely known to be an effective cure for diabetes mellitus, is also a functional crop. This study was conducted to examine the effects of light quality and intensity of monochromatic light-emitting diodes (LEDs) on ice plant growth and phytochemical concentrations in a closed-type plant production system. Ice plant seedlings were transplanted into a deep floating technique system with a recycling nutrient solution (EC 4.0 dS m−1, pH 6.5). Fluorescent lamps, as well as monochromatic red (660 nm) and blue (450 nm) LEDs, were used at 120 ± 5 or 150 ± 5 µmol m−2 s−1 PPFD with a photoperiod of 14 h/10 h (light/dark) for 4 weeks. Ice plants showed higher growth under the high light intensity treatment, especially under the red LEDs. Furthermore, the SPAD value and photosynthetic rate were higher under the red LEDs with 150 µmol m−2 s−1 PPFD. The ice plant phytochemical composition, such as antioxidant activity and myo-inositol and pinitol concentrations, were highest under the blue LEDs with 150 µmol m−2 s−1 PPFD. Total phenolic concentration was highest under the blue LEDs with 120 µmol m−2 s−1 PPFD. Despite a slightly different dependence on light intensity, phytochemical concentrations responded positively to the blue LED treatments, as compared to other treatments. In conclusion, this study suggests that red LEDs enhance ice plant biomass, while blue LEDs induce phytochemical
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 (up) Edition
ISSN 2211-3452 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 1983
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Author El-Bakry, H.A.; Ismail, I.A.; Soliman, S.S.
Title Immunosenescence-like state is accelerated by constant light exposure and counteracted by melatonin or turmeric administration through DJ-1/Nrf2 and P53/Bax pathways Type Journal Article
Year 2018 Publication Journal of Photochemistry and Photobiology. B, Biology Abbreviated Journal J Photochem Photobiol B
Volume 186 Issue Pages 69-80
Keywords Animals
Abstract The awareness of the interrelationship between immunosenescence and constant light exposure can provide new insights into the consequences of excessive exposure to light at night due to light pollution or shift work. Here, we investigated whether constant light exposure (LL) acts as an inducer of immunosenescence. We also determined the role of melatonin or turmeric in reversing the putative effects of constant light and explored for the first time the underlying molecular mechanisms. Young (3-4-month-old) rats were exposed daily to LL alone or in combination with each of melatonin and turmeric for 12weeks. A group of aged rats (18-months old; n=6) was used as a reference for natural immunosenescence. Constant light exposure resulted in remarkable pathophysiological alterations resembling those noticed in normal aged rats, manifested as apparent decreases in antioxidant activities as well as Nrf2 and DJ-1 expressions, striking augmentation in oxidative stress, proinflammatory cytokines and expression of TNFalpha, Bax, and p53 genes, and deleterious changes of lymphoid organs, Co-administration of melatonin or turmeric was able to reverse all alterations induced by LL through upregulation of Nrf2/DJ-1 and downregulation of p53/Bax pathways. These data suggest that LL accelerates immunosenescence via oxidative stress and apoptotic pathways. They also demonstrate for the first time that turmeric is comparable to melatonin in boosting the immune function and counteracting the LL-associated immunosenescence. These effects suggest that turmeric supplementation can be used as an inexpensive intervention to prevent circadian disruption-related immunosenescence. However, to validate the effects of turmeric on humans further studies are warranted.
Address Department of Zoology & Entomology, Faculty of Science, Minia University, Egypt
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 (up) Edition
ISSN 1011-1344 ISBN Medium
Area Expedition Conference
Notes PMID:30015062 Approved no
Call Number GFZ @ kyba @ Serial 1984
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Author Souman, J.L.; Borra, T.; de Goijer, I.; Schlangen, L.J.M.; Vlaskamp, B.N.S.; Lucassen, M.P.
Title Spectral Tuning of White Light Allows for Strong Reduction in Melatonin Suppression without Changing Illumination Level or Color Temperature Type Journal Article
Year 2018 Publication Journal of Biological Rhythms Abbreviated Journal J Biol Rhythms
Volume 33 Issue 4 Pages 420-431
Keywords Human Health; Lighting
Abstract Studies with monochromatic light stimuli have shown that the action spectrum for melatonin suppression exhibits its highest sensitivity at short wavelengths, around 460 to 480 nm. Other studies have demonstrated that filtering out the short wavelengths from white light reduces melatonin suppression. However, this filtering of short wavelengths was generally confounded with reduced light intensity and/or changes in color temperature. Moreover, it changed the appearance from white light to yellow/orange, rendering it unusable for many practical applications. Here, we show that selectively tuning a polychromatic white light spectrum, compensating for the reduction in spectral power between 450 and 500 nm by enhancing power at even shorter wavelengths, can produce greatly different effects on melatonin production, without changes in illuminance or color temperature. On different evenings, 15 participants were exposed to 3 h of white light with either low or high power between 450 and 500 nm, and the effects on salivary melatonin levels and alertness were compared with those during a dim light baseline. Exposure to the spectrum with low power between 450 and 500 nm, but high power at even shorter wavelengths, did not suppress melatonin compared with dim light, despite a large difference in illuminance (175 vs. <5 lux). In contrast, exposure to the spectrum with high power between 450 and 500 nm (also 175 lux) resulted in almost 50% melatonin suppression. For alertness, no significant differences between the 3 conditions were observed. These results open up new opportunities for lighting applications that allow for the use of electrical lighting without disturbance of melatonin production.
Address Philips Lighting Research, Department Lighting Applications, Eindhoven, The Netherlands
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 (up) Edition
ISSN 0748-7304 ISBN Medium
Area Expedition Conference
Notes PMID:29984614 Approved no
Call Number GFZ @ kyba @ Serial 1985
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Author Ostrin, L.A.
Title Ocular and systemic melatonin and the influence of light exposure Type Journal Article
Year 2018 Publication Clinical & Experimental Optometry Abbreviated Journal Clin Exp Optom
Volume in press Issue Pages in press
Keywords Vision; Review; Human Health
Abstract Melatonin is a neurohormone known to modulate a wide range of circadian functions, including sleep. The synthesis and release of melatonin from the pineal gland is heavily influenced by light stimulation of the retina, particularly through the intrinsically photosensitive retinal ganglion cells. Melatonin is also synthesised within the eye, although to a much lesser extent than in the pineal gland. Melatonin acts directly on ocular structures to mediate a variety of diurnal rhythms and physiological processes within the eye. The interactions between melatonin, the eye, and visual function have been the subject of a considerable body of recent research. This review is intended to provide a broad introduction for eye-care practitioners and researchers to the topic of melatonin and the eye. The first half of the review describes the anatomy and physiology of melatonin production: how visual inputs affect the pineal production of melatonin; how melatonin is involved in a variety of diurnal rhythms within the eye, including photoreceptor disc shedding, neuronal sensitivity, and intraocular pressure control; and melatonin production and physiological roles in retina, ciliary body, lens and cornea. The second half of the review describes clinical implications of light/melatonin interactions. These include light exposure and photoreceptor contributions in melatonin suppression, leading to consideration of how blue blockers, cataract, and light therapy might affect sleep and mood in patients. Additionally, the interactions between melatonin, sleep and refractive error development are discussed. A better understanding of environmental factors that affect melatonin and subsequent effects on physiological processes will allow clinicians to develop treatments and recommend modifiable behaviours to improve sleep, increase daytime alertness, and regulate ocular and systemic processes related to melatonin.
Address University of Houston College of Optometry, Houston, Texas, USA
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 (up) Edition
ISSN 0816-4622 ISBN Medium
Area Expedition Conference
Notes PMID:30074278 Approved no
Call Number GFZ @ kyba @ Serial 1986
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Author Nickla, D.L.
Title Ocular diurnal rhythms and eye growth regulation: where we are 50 years after Lauber Type Journal Article
Year 2013 Publication Experimental eye Research Abbreviated Journal Exp Eye Res
Volume 114 Issue Pages 25-34
Keywords Vision; Human Health; Review
Abstract Many ocular processes show diurnal oscillations that optimize retinal function under the different conditions of ambient illumination encountered over the course of the 24 h light/dark cycle. Abolishing the diurnal cues by the use of constant darkness or constant light results in excessive ocular elongation, corneal flattening, and attendant refractive errors. A prevailing hypothesis is that the absence of the Zeitgeber of light and dark alters ocular circadian rhythms in some manner, and results in an inability of the eye to regulate its growth in order to achieve emmetropia, the matching of the front optics to eye length. Another visual manipulation that results in the eye growth system going into a “default” mode of excessive growth is form deprivation, in which a translucent diffuser deprives the eye of visual transients (spatial or temporal) while not significantly reducing light levels; these eyes rapidly elongate and become myopic. It has been hypothesized that form deprivation might constitute a type of “constant condition” whereby the absence of visual transients drives the eye into a similar default mode as that in response to constant light or dark. Interest in the potential influence of light cycles and ambient lighting in human myopia development has been spurred by a recent study showing a positive association between the amount of time that children spent outdoors and a reduced prevalence of myopia. The growing eyes of chickens and monkeys show a diurnal rhythm in axial length: Eyes elongate more during the day than during the night. There is also a rhythm in choroidal thickness that is in approximate anti-phase to the rhythm in eye length. The phases are altered in eyes growing too fast, in response to form deprivation or negative lenses, or too slowly, in response to myopic defocus, suggesting an influence of phase on the emmetropization system. Other potential rhythmic influences include dopamine and melatonin, which form a reciprocal feedback loop, and signal “day” and “night” respectively. Retinal dopamine is reduced during the day in form deprived myopic eyes, and dopamine D2 agonists inhibit ocular growth in animal models. Rhythms in intraocular pressure as well, may influence eye growth, perhaps as a mechanical stimulus triggering changes in scleral extracellular matrix synthesis. Finally, evidence shows varying influences of environmental lighting parameters on the emmetropization system, such as high intensity light being protective against myopia in chickens. This review will cover the evidence for the possible influence of these various factors on ocular growth. The recognition that ocular rhythms may play a role in emmetropization is a first step toward understanding how they may be manipulated in treatment therapies to prevent myopia in humans.
Address New England College of Optometry, Department of Biosciences, 424 Beacon Street, Boston, MA 02115, USA. nicklad@neco.edu
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 (up) Edition
ISSN 0014-4835 ISBN Medium
Area Expedition Conference
Notes PMID:23298452; PMCID:PMC3742730 Approved no
Call Number GFZ @ kyba @ Serial 1987
Permanent link to this record