Suppression of men's responses to seasonal changes in day length by modern artificial lighting

1995 ◽  
Vol 269 (1) ◽  
pp. R173-R178 ◽  
Author(s):  
T. A. Wehr ◽  
H. A. Giesen ◽  
D. E. Moul ◽  
E. H. Turner ◽  
P. J. Schwartz
Keyword(s):  
Urban Environment ◽  
Rectal Temperature ◽  
Seasonal Changes ◽  
Day Length ◽  
Constant Darkness ◽  
Artificial Light ◽  
Active Secretion ◽  
Artificial Lighting ◽  
Natural Photoperiod ◽  
Low Levels

We recently reported that humans have conserved mechanisms, like those that exist in other animals, which detect changes in day length and make corresponding adjustments in the duration of nocturnal periods of secretion of melatonin and of other functions. We detected these responses in individuals who were exposed to artificial "days" of different durations. The purpose of the present study was to determine whether men who are exposed to natural and artificial light in an urban environment at 39 degrees N are still able to detect and respond to seasonal changes in duration of the natural photoperiod. We measured profiles of circadian rhythms during 24-h periods of constant darkness (< 1 lx) and found no summer-winter differences in durations of nocturnal periods of active secretion of melatonin, rising levels of cortisol, high levels of thyrotropin, and low levels of rectal temperature. The results of this and our previous study suggest that modern men's use of artificial light suppresses responses to seasonal changes in the natural photoperiod that might otherwise occur at this latitude.

scholarly journals Photoperiodic induction without light-mediated circadian entrainment in a High Arctic resident bird

2020 ◽  
Vol 223 (16) ◽  
pp. jeb220699 ◽  
Author(s):  
Daniel Appenroth ◽  
Vebjørn J. Melum ◽  
Alexander C. West ◽  
Hugues Dardente ◽  
David G. Hazlerigg ◽  
...  
Keyword(s):  
Activity Patterns ◽  
High Arctic ◽  
Gonadal Development ◽  
Photoperiodic Response ◽  
Day Length ◽  
The Arctic ◽  
Constant Darkness ◽  
Polar Regions ◽  
Natural Photoperiod ◽  
Lagopus Muta

ABSTRACTOrganisms use changes in photoperiod to anticipate and exploit favourable conditions in a seasonal environment. While species living at temperate latitudes receive day length information as a year-round input, species living in the Arctic may spend as much as two-thirds of the year without experiencing dawn or dusk. This suggests that specialised mechanisms may be required to maintain seasonal synchrony in polar regions. Svalbard ptarmigan (Lagopus muta hyperborea) are resident at 74–81°N latitude. They spend winter in constant darkness (DD) and summer in constant light (LL); extreme photoperiodic conditions under which they do not display overt circadian rhythms. Here, we explored how Arctic adaptation in circadian biology affects photoperiodic time measurement in captive Svalbard ptarmigan. For this purpose, DD-adapted birds, showing no circadian behaviour, either remained in prolonged DD, were transferred into a simulated natural photoperiod (SNP) or were transferred directly into LL. Birds transferred from DD to LL exhibited a strong photoperiodic response in terms of activation of the hypothalamic thyrotropin-mediated photoperiodic response pathway. This was assayed through expression of the Eya3, Tshβ and deiodinase genes, as well as gonadal development. While transfer to SNP established synchronous diurnal activity patterns, activity in birds transferred from DD to LL showed no evidence of circadian rhythmicity. These data show that the Svalbard ptarmigan does not require circadian entrainment to develop a photoperiodic response involving conserved molecular elements found in temperate species. Further studies are required to define how exactly Arctic adaptation modifies seasonal timer mechanisms.

scholarly journals Artificial light at night shifts daily activity patterns but not the internal clock in the great tit ( Parus major )

2018 ◽  
Vol 285 (1875) ◽  
pp. 20172751 ◽  
Author(s):  
Kamiel Spoelstra ◽  
Irene Verhagen ◽  
Davy Meijer ◽  
Marcel E. Visser
Keyword(s):  
Phase Shift ◽  
Daily Activity ◽  
Parus Major ◽  
Internal Clock ◽  
Circadian System ◽  
Constant Darkness ◽  
Artificial Light ◽  
Light At Night ◽  
Dim Light ◽  
Low Levels

Artificial light at night has shown a dramatic increase over the last decades and continues to increase. Light at night can have strong effects on the behaviour and physiology of species, which includes changes in the daily timing of activity; a clear example is the advance in dawn song onset in songbirds by low levels of light at night. Although such effects are often referred to as changes in circadian timing, i.e. changes to the internal clock, two alternative mechanisms are possible. First, light at night can change the timing of clock controlled activity, without any change to the clock itself; e.g. by a change in the phase relation between the circadian clock and expression of activity. Second, changes in daily activity can be a direct response to light (‘masking’), without any involvement of the circadian system. Here, we studied whether the advance in onset of activity by dim light at night in great tits ( Parus major ) is indeed attributable to a phase shift of the internal clock. We entrained birds to a normal light/dark (LD) cycle with bright light during daytime and darkness at night, and to a comparable (LDim) schedule with dim light at night. The dim light at night strongly advanced the onset of activity of the birds. After at least six days in LD or LDim, we kept birds in constant darkness (DD) by leaving off all lights so birds would revert to their endogenous, circadian system controlled timing of activity. We found that the timing of onset in DD was not dependent on whether the birds were kept at LD or LDim before the measurement. Thus, the advance of activity under light at night is caused by a direct effect of light rather than a phase shift of the internal clock. This demonstrates that birds are capable of changing their daily activity to low levels of light at night directly, without the need to alter their internal clock.

Twilight and day length affects the seasonality of entrainment and endogenous circadian rhythms in a fish, Couesius plumbeus

1981 ◽  
Vol 59 (7) ◽  
pp. 1326-1334 ◽  
Author(s):  
Martin Kavaliers ◽  
Donald M. Ross
Keyword(s):  
Circadian Rhythms ◽  
Seasonal Changes ◽  
Phase Relationship ◽  
Day Length ◽  
Constant Darkness ◽  
Diurnal Activity ◽  
Circadian Period ◽  
Dark Cycle ◽  
Environmental Light ◽  
Couesius Plumbeus

Twilight and day-length portions of the light-dark cycle determine the seasonal course of (i) the phase relationship (ψ) between activity and the daily environmental light–dark cycle, (ii) the duration of activity (α), and (iii) the circadian period (τ) under constant darkness of the lake chub (Couesius plumbeus). With fish held under seasonally appropriate light–dark cycles with twilight (LD + t), the onset of diurnal activity occurred during dawn and its timing (ψonset) followed a bimodal annual pattern that was correlated with seasonal changes in the duration and physical characteristics of twilight. The end of activity occurred during dusk (ψoffset) and followed a unimodal annual pattern that was determined by day length. α followed a sigmoidal annual pattern under LD + t. The circadian period underwent significant seasonal changes with maximum and minimum τ values occurring during summer and winter, respectively. Fish that were entrained to rectangular light–dark cycles that excluded twilights (LD) failed to show any seasonal changes in ψ and τ and the sigmoidal relation between α and day length was absent.

scholarly journals Continuous Lighting Reduces Conidial Production and Germinability in the Rose Powdery Mildew Pathosystem

Plant Disease ◽  
2010 ◽  
Vol 94 (3) ◽  
pp. 339-344 ◽  
Author(s):  
A. Suthaparan ◽  
Arne Stensvand ◽  
S. Torre ◽  
Maria L. Herrero ◽  
R. I. Pettersen ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Disease Severity ◽  
Interspecific Hybrid ◽  
Day Length ◽  
Artificial Light ◽  
Potted Plants ◽  
Severity Of Disease ◽  
Detached Leaves ◽  
Growth Chambers ◽  
The Rose

The effect of day length on production and germinability of conidia and severity of disease caused by Podosphaera pannosa, the causal agent of rose powdery mildew, was studied. Whole potted plants or detached leaves of Rosa interspecific hybrid ‘Mistral’ were inoculated with P. pannosa and exposed to 0, 12, 18, 20, 22, or 24 h of artificial light per day in growth chambers equipped with mercury lamps. Increasing duration of illumination from 18 to 20 to 24 h per day reduced production of conidia by 22 to 62%. Exposure to 24 h of illumination per day also strongly reduced disease severity compared with 18 h. Our results suggest that increasing day lengths from 18 h per day to 20 to 24 h may suppress the disease significantly and, thereby, reduce the need for fungicide applications against powdery mildew.

scholarly journals The strategy of creating highly productive forms of radish, adapted for cultivation under artificial light conditions

2019 ◽  
Vol 1 (1) ◽  
pp. 29-33 ◽  
Author(s):  
A. A. Kochetov ◽  
N. G. Sinyavina
Keyword(s):  
Small Volume ◽  
Morphological Characteristics ◽  
Intraspecific Diversity ◽  
Artificial Light ◽  
Light Conditions ◽  
Early Maturity ◽  
Artificial Lighting ◽  
First And Second Generation ◽  
Incandescent Lamps ◽  
Different Origin

The strategy of creating new radish forms adapted for cultivation under artificial lighting was developed and implemented. It was based on the original methodology of obtaining transgressive forms of various cultures with a predictable complex of economically valuable properties. Plants were grown in controlled conditions, under incandescent lamps DNAZ-400 (12 hours photoperiod, irradiation of 40-60 W/m2 PAR), in a small volume of the root medium. At the first stage, the intraspecific diversity of radish (26 varieties of different origin) under artificial lighting has been studied. Differences between varieties were determined for the complex of selective-valuable characteristics (early maturity, productivity, morphological characteristics). The most productive varieties are revealed, as well as varieties donors of economically valuable properties that are realized under artificial lighting at a short day and high temperature. Parent pairs have been selected for the subsequent receipt of highly productive transgressive forms using the original breeding methodology. The evaluation of hybrids of the first and second generation showed the presence of heterosis on the mass of the root up to 230% in various combinations of hybridization and revealed promising transgressive forms.

Flowering of Stylosanthes guianensis in controlled temperatures under natural photoperiod

1984 ◽  
Vol 35 (2) ◽  
pp. 219 ◽  
Author(s):  
RL Ison ◽  
LR Humphreys
Keyword(s):  
Floral Initiation ◽  
Minimum Duration ◽  
Stylosanthes Guianensis ◽  
Short Day ◽  
Long Day ◽  
Natural Photoperiod ◽  
Low Levels ◽  
Short Days

Seedlings of Stylosanthes guianensis var. guianensis cv. Cook and cv. Endeavour were grown in naturally lit glasshouses at Brisbane (lat. 27� 30' S.) at 35/30, 30/25 and 25/20�C (day/night), and were sown so as to emerge at 18-day intervals from 18 January to 11 June. Cook behaved as a long day-short day plant, with seedlings emerging after 5 February flowering incompletely or remaining vegetative until the experiment was terminated in mid-October. In the 25/20�C regimen flowering was incomplete in Cook; in Endeavour flowering was delayed but a conventional short-day response was observed. At 35/30�C Endeavour flowering was inhibited in the shortest days of mid-winter, suggesting a stenophotoperiodic response, but short days were confounded with low levels of irradiance. Minimum duration of the phase from emergence to floral initiation was c. 66-70 days in Cook and c. 40-45 days in Endeavour; the duration of the phase floral initiation to flower appearance was linearly and negatively related to temperature.

Temperature modulation of photoperiodism and the timing of late-season changes in life history for an aphid, Acyrthosiphon pisum

2011 ◽  
Vol 143 (1) ◽  
pp. 56-71 ◽  
Author(s):  
M.A.H. Smith ◽  
P.A. MacKay ◽  
R.J. Lamb
Keyword(s):  
Sexual Reproduction ◽  
Seasonal Changes ◽  
Acyrthosiphon Pisum ◽  
Late Summer ◽  
Day Length ◽  
Temperature Modulation ◽  
Four Seasons ◽  
Aphid Clone ◽  
Photoperiodic Responses

AbstractWhere winters are severe, aphids reproduce parthenogenetically and viviparously in summer, switch to sexual reproduction in late summer, and produce winter-hardy eggs by the end of the season. The role of day length and temperature in initiating seasonal changes from parthenogenetic to sexual reproduction by pea aphids, Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae), are described and the selection pressures that affect the timing of this transition are investigated. Over four seasons, a pea aphid clone was sampled from field cages through late summer in southern Manitoba, Canada, and reared in the laboratory to determine the phenotypes of progeny produced as the season progressed. The timing of transitions from one phenotype to another under natural day length and temperature, and the critical day lengths that caused the transitions, coincided with expectations from laboratory studies of photoperiodic responses. Males and mating females appeared later when the weather in August was warm than when it was cool. The timing of seasonal changes was adapted to minimize the physiological time to the end of the season, which maximized the number of asexual summer generations. Ambient temperature modulated the response to day length and fine-tuned the timing of sexual reproduction to adapt for annual variation in autumn weather.

scholarly journals Photoperiodic regulation of prolactin secretion: changes in intra-pituitary signalling and lactotroph heterogeneity

2004 ◽  
Vol 180 (3) ◽  
pp. 351-356 ◽  
Author(s):  
JD Johnston
Keyword(s):  
Environmental Conditions ◽  
Seasonal Changes ◽  
Mammalian Species ◽  
Prolactin Secretion ◽  
Day Length ◽  
Pars Tuberalis ◽  
Photoperiodic Regulation ◽  
Pituitary Lactotroph

Many mammalian species utilise day-length (photoperiod) to adapt their physiology to seasonal changes in environmental conditions, via secretion of pineal melatonin. Photoperiodic regulation of prolactin secretion is believed to occur via melatonin-mediated changes in the secretion of a putative prolactin secretagogue, tuberalin, from the pituitary pars tuberalis. Despite the in vivo and in vitro evidence in support of this intra-pituitary signalling mechanism, the identity of tuberalin has yet to be elucidated. This paper reviews recent advances in the characterisation of tuberalin and the regulation of its secretion. Furthermore, the hypothesis that pituitary lactotroph cells display heterogeneity in their response to changing photoperiod and tuberalin secretion is examined.

Household Consumption of Artificial Light at Pompeii

2018 ◽  
Author(s):  
David G. Griffiths
Keyword(s):  
Olive Oil ◽  
Urban Environment ◽  
Household Consumption ◽  
Roman Period ◽  
Contextual Analysis ◽  
Artificial Light ◽  
Goods And Services ◽  
Human Interactions ◽  
Abundant Evidence ◽  
Household Activities

The ability to engage in nocturnal household activities influences human interactions with each other and the urban environment. The illumination of Pompeian households, through both natural and artificial means, had an impact on architectural proportions, decoration, and the organization and use of space. The Roman period witnessed dramatic increases in the scale of consumption for all types of goods and services throughout the empire. This was also the case for the consumption of artificial light, where there is abundant evidence for lighting devices, especially from Pompeian households, but also for the supply of lamp fuel through the presence of olive oil amphora at most Roman sites throughout the Mediterranean. This chapter presents the contextual analysis of the use of artificial light at ten households in Pompeii in 79 ce.

Simulated natural day lengths synchronize seasonal rhythms of asynchronously born male Siberian hamsters

2007 ◽  
Vol 293 (1) ◽  
pp. R402-R412 ◽  
Author(s):  
Matthew P. Butler ◽  
Kevin W. Turner ◽  
Jin Ho Park ◽  
James P. Butler ◽  
Justin J. Trumbull ◽  
...  
Keyword(s):  
Somatic Growth ◽  
Day Length ◽  
Delayed Puberty ◽  
Testicular Development ◽  
Early Puberty ◽  
Seasonal Rhythms ◽  
Siberian Hamsters ◽  
Natural Photoperiod ◽  
Timing Of Puberty ◽  
Short Days

Photoperiodism research has relied on static day lengths and abrupt transitions between long and short days to characterize the signals that drive seasonal rhythms. To identify ecologically relevant critical day lengths and to test the extent to which naturally changing day lengths synchronize important developmental events, we monitored nine cohorts of male Siberian hamsters ( Phodopus sungorus) born every 2 wk from 4 wk before to 12 wk after the summer solstice in a simulated natural photoperiod (SNP). SNP hamsters born from 4 wk before to 2 wk after the solstice underwent rapid somatic and gonadal growth; among those born 4–6 wk after the solstice, some delayed puberty by many weeks, whereas others manifested early puberty. Hamsters born eight or more weeks after the solstice failed to undergo early testicular development. The transition to delayed development occurred at long day lengths, which induce early puberty when presented as static photoperiods. The first animals to delay puberty may do so predominantly on the basis of postnatal decreases in day length, whereas in later cohorts, a comparison of postnatal day length to gestational day length may contribute to arrested development. Despite differences in timing of birth and timing of puberty, autumn gonadal regression and spring gonadal and somatic growth occurred at similar calendar dates in all cohorts. Incrementally changing photoperiods exert a strong organizing effect on seasonal rhythms by providing hamsters with a richer source of environmental timing cues than are available in simple static day lengths.

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