Histochemical correlates of changes in the primate brain associated with varying environmental light conditions

Histochemie ◽  
1973 ◽  
Vol 34 (3) ◽  
pp. 217-225 ◽  
Author(s):  
Sohan L. Manocha ◽  
Adrian A. Perachio
Keyword(s):  
Light Conditions ◽  
Primate Brain ◽  
Environmental Light

scholarly journals Isomeric composition of bacteriorhodopsin under different environmental light conditions

FEBS Letters ◽  
1979 ◽  
Vol 97 (1) ◽  
pp. 129-132 ◽  
Author(s):  
Walter Sperling ◽  
Charles N. Rafferty ◽  
Klaus-Dieter Kohl ◽  
Norbert A. Dencher
Keyword(s):  
Isomeric Composition ◽  
Light Conditions ◽  
Environmental Light

scholarly journals Aging Affects the Capacity of Photoperiodic Adaptation Downstream from the Central Molecular Clock

2020 ◽  
Vol 35 (2) ◽  
pp. 167-179 ◽  
Author(s):  
M. Renate Buijink ◽  
Anneke H. O. Olde Engberink ◽  
Charlotte B. Wit ◽  
Assaf Almog ◽  
Johanna H. Meijer ◽  
...  
Keyword(s):  
Molecular Clock ◽  
The Elderly ◽  
Light Conditions ◽  
Targeted Interventions ◽  
The Core ◽  
Environmental Light ◽  
Age Related ◽  
Wake Patterns ◽  
Central Clock ◽  
Membrane Components

Aging impairs circadian clock function, leading to disrupted sleep-wake patterns and a reduced capability to adapt to changes in environmental light conditions. This makes shift work or the changing of time zones challenging for the elderly and, importantly, is associated with the development of age-related diseases. However, it is unclear what levels of the clock machinery are affected by aging, which is relevant for the development of targeted interventions. We found that naturally aged mice of >24 months had a reduced rhythm amplitude in behavior compared with young controls (3-6 months). Moreover, the old animals had a strongly reduced ability to adapt to short photoperiods. Recording PER2::LUC protein expression in the suprachiasmatic nucleus revealed no impairment of the rhythms in PER2 protein under the 3 different photoperiods tested (LD: 8:16, 12:12, and 16:8). Thus, we observed a discrepancy between the behavioral phenotype and the molecular clock, and we conclude that the aging-related deficits emerge downstream of the core molecular clock. Since it is known that aging affects several intracellular and membrane components of the central clock cells, it is likely that an impairment of the interaction between the molecular clock and these components is contributing to the deficits in photoperiod adaptation.

scholarly journals The effects of colour and temporal frequency of flickering light on variability of the accommodation response in emmetropes and myopes

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Liyue Zhang ◽  
Dongyu Guo ◽  
Chen Xie ◽  
Yingying Wen ◽  
Xuhong Zhang ◽  
...  
Keyword(s):  
Open Field ◽  
Daily Life ◽  
Temporal Frequency ◽  
Light Conditions ◽  
Flicker Frequency ◽  
Blue Colour ◽  
Low Frequencies ◽  
Flickering Light ◽  
Under Five ◽  
Environmental Light

Abstract Background Myopia is hypothesized to be influenced by environmental light conditions. For example, it has been shown that colour and temporal frequency of flickering light affect emmetropisation in animals. Considering the omnipresence of flickering light in our daily life, we decided to analyze the effect of colour flickers on variability of the accommodation response (VAR) in emmetropes and myopes. Methods We measured the dynamic accommodative responses of 19 emmetropic and 22 myopic adults using a Grand Seiko WAM-5500 open-field autorefractor. The subjects focused for more than 20 s on a black Snellen E target against three different backgrounds made up of three colour flicker combinations (red/green, red/blue and blue/green) and under five frequency conditions (0.20 Hz, 0.50 Hz, 1.00 Hz, 1.67 Hz, and 5.00 Hz). Results Flicker frequency and colour both had a significant effect on VAR. Lower frequencies were associated with larger variability. Colour had an effect only at low frequencies, and red/blue colour flicker resulted in the largest variability. The variability in myopes were larger than those in emmetropes. Conclusions These findings support the hypothesis that further studies on the colour and temporal frequency of flickering light can lead to a better understanding of the development and progression of myopia.

LIGHT—A TIME FOR CHANGE TO "RADIANT FLUX," OR MICROWATTS PER SQUARE CENTIMETER (µW/CM2)

PEDIATRICS ◽  
1972 ◽  
Vol 50 (1) ◽  
pp. 5-5
Author(s):  
Jerold F. Lucey
Keyword(s):  
Seasonal Variations ◽  
Radiant Flux ◽  
Light Conditions ◽  
Environmental Light

Some simple therapies are often used but little understood. Anybody using phototherapy should read with care the two articles about light in this issue. That by Drs. MacLeod and Stern calls attention to and documents in the traditional way, using foot candles and a simple light meter, the wide daily and seasonal variations in environmental light conditions that can occur in nurseries. To many, even the term "foot candles" is a new unit with little meaning until recently. If you then turn to the article by Dr. Klein, a photobiologist, you will be convinced that it is not only a very crude, inaccurate way of expressing something important to us all, but it is actually the wrong unit!

scholarly journals Central Interleukin-1βSuppresses the Nocturnal Secretion of Melatonin

2016 ◽  
Vol 2016 ◽  
pp. 1-15 ◽  
Author(s):  
A. P. Herman ◽  
J. Bochenek ◽  
K. Król ◽  
A. Krawczyńska ◽  
H. Antushevich ◽  
...  
Keyword(s):  
Biosynthetic Pathway ◽  
Tryptophan Hydroxylase ◽  
Common Elements ◽  
Light Conditions ◽  
Melatonin Secretion ◽  
Environmental Light ◽  
The Central Nervous System ◽  
Intracerebroventricular Injections ◽  
Hormonal Signal

In vertebrates, numerous processes occur in a rhythmic manner. The hormonal signal reliably reflecting the environmental light conditions is melatonin. Nocturnal melatonin secretion patterns could be disturbed in pathophysiological states, including inflammation, Alzheimer’s disease, and depression. All of these states share common elements in their aetiology, including the overexpression of interleukin- (IL-) 1βin the central nervous system. Therefore, the present study was designed to determine the effect of the central injection of exogenous IL-1βon melatonin release and on the expression of the enzymes of the melatonin biosynthetic pathway in the pineal gland of ewe. It was found that intracerebroventricular injections of IL-1β(50 µg/animal) suppressed(P<0.05)nocturnal melatonin secretion in sheep regardless of the photoperiod. This may have resulted from decreased(P<0.05)synthesis of the melatonin intermediate serotonin, which may have resulted, at least partially, from a reduced expression of tryptophan hydroxylase. IL-1βalso inhibited(P<0.05)the expression of the melatonin rhythm enzyme arylalkylamine-N-acetyltransferase and hydroxyindole-O-methyltransferase. However, the ability of IL-1βto affect the expression of these enzymes was dependent upon the photoperiod. Our study may shed new light on the role of central IL-1βin the aetiology of disruptions in melatonin secretion.

scholarly journals Maternal Environmental Light Conditions Affect the Morphological Allometry and Dispersal Potential of Acer palmatum Samaras

Forests ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1313
Author(s):  
Bin J. W. Chen ◽  
Xinyu Wang ◽  
Yuting Dong ◽  
Heinjo J. During ◽  
Xia Xu ◽  
...  
Keyword(s):  
Size Range ◽  
Light Condition ◽  
Morphological Plasticity ◽  
Terminal Velocity ◽  
Light Conditions ◽  
Maternal Control ◽  
Large Size ◽  
Environmental Light ◽  
Species Survival ◽  
Dispersal Potential

Seed dispersal plays critical roles in determining species survival and community structures. Since the dispersal is biologically under maternal control, it is hypothesized that intraspecific variation of dispersal potential and associated traits of seeds (diaspores) should be influenced by maternal habitat quality. We tested this hypothesis by examining the effects of maternal environmental light condition on morphological traits and descending performance of nearly 1800 wind-dispersed samaras collected from maple species Acer palmatum. Results showed that samaras produced by trees from shaded microhabitats had greater dispersal potential, in terms of slower terminal velocity of descent, than those produced in open microhabitats. This advantage was largely attributed to morphological plasticity. On average, samaras produced in shaded microhabitats, as compared to those produced in open habitats, had lower wing loading by only reducing weight but not area. In allometric details, in the large size range, samaras from shaded microhabitats had larger areas than those from open microhabitats; in the small size range, samaras from shaded microhabitats had wider wings. These findings suggest that greater dispersal potential of samaras in response to stressful maternal light environment reflected an active maternal control through the morphological allometry of samaras.

scholarly journals Sclera color in humans facilitates gaze perception during daytime and nighttime

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0249137
Author(s):  
Jessica L. Yorzinski ◽  
Amy Harbourne ◽  
William Thompson
Keyword(s):  
Environmental Conditions ◽  
Homo Sapiens ◽  
Human Subjects ◽  
Light Conditions ◽  
Gaze Perception ◽  
Direct Gaze ◽  
Eye Morphology ◽  
Environmental Light ◽  
Averted Gaze

Species vary widely in the conspicuousness of their eye morphology and this could influence gaze perception. Eyes with conspicuous morphology can enhance gaze perception while eyes with camouflaged morphology may hinder gaze perception. While evidence suggests that conspicuous eye morphology enhances gaze perception, little is known about how environmental conditions affect this interaction. Thus, we investigated whether environmental light conditions affect gaze perception. Human subjects (Homo sapiens) were instructed to find direct-gaze faces within arrays of averted-gaze faces or to find averted-gaze faces within arrays of directed-gaze faces. The faces were displayed under conditions simulating nighttime or daytime conditions. Furthermore, the faces had naturally-colored sclera (white) or modified sclera (same color as the iris). Participants were fastest and most accurate in detecting faces during the daytime and nighttime conditions when the sclera were naturally-colored. Participants were worst at detecting faces with modified sclera during the nighttime conditions. These results suggest that eyes with conspicuous morphology enhance gaze perception during both daytime and nighttime conditions.

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