The effect of photoperiod on the timing of larval release in the Mediterranean brood-care polychaete Eupolymnia nebulosa (Terebellida)

2003 ◽  
Vol 83 (6) ◽  
pp. 1227-1228 ◽  
Author(s):  
Christian Nozais ◽  
Jean Claude Duchêne ◽  
François Charles ◽  
Sébastien Mas
Keyword(s):  
Brood Care ◽  
Dark Cycle ◽  
Larval Release ◽  
Larval Emergence ◽  
The Mediterranean ◽  
Effect Of Light

The effect of light–dark cycle on the timing of larval release from jelly masses of the Mediterranean polychaete Eupolymnia nebulosa (Terebellida) was investigated. The larval emergence from the jelly mass occurs mainly during daylight. Results suggest that the larvae of E. nebulosa do not track the light–dark cycle endogenously.

Effect of Light/Dark Cycle on Wheel Running and Responding Reinforced by the Opportunity to Run Depends on Postsession Feeding Time

2008 ◽  
Vol 58 (3) ◽  
pp. 391-404 ◽  
Author(s):  
T. W. Belke ◽  
A. R. Mandrona ◽  
K. M. Conrad ◽  
K. F. Poirier ◽  
K. L. Pickering
Keyword(s):  
Wheel Running ◽  
Feeding Time ◽  
Dark Cycle ◽  
Effect Of Light

scholarly journals Effect of light/dark cycle on nitrate and phosphate removal from synthetic wastewater based on BG11 medium by Scenedesmus sp.

3 Biotech ◽  
2019 ◽  
Vol 9 (4) ◽  
Author(s):  
Adnan Habibi ◽  
Ghorban Ali Nematzadeh ◽  
Farshid Pajoum shariati ◽  
Hossein Delavari Amrei ◽  
Abolghasem Teymouri
Keyword(s):  
Phosphate Removal ◽  
Synthetic Wastewater ◽  
Dark Cycle ◽  
Bg11 Medium ◽  
Effect Of Light

scholarly journals Resetting Process of Peripheral Circadian Gene Expression after the Combined Reversal of Feeding Schedule and Light/Dark Cycle Via a 24-h Light Period Transition in Rats

2010 ◽  
pp. 581-590
Author(s):  
T Wu ◽  
Y Ni ◽  
F Zhuge ◽  
Z Fu
Keyword(s):  
Time Course ◽  
Clock Genes ◽  
Dark Period ◽  
Light Period ◽  
Feeding Schedule ◽  
Circadian Gene ◽  
Dark Cycle ◽  
Peripheral Clocks ◽  
Effect Of Light

To investigate the effect of light cue on the resetting of the peripheral clocks, we examined the resetting processes of clock genes (Per1, Per2, Bmal1, Cry1, Dec1, and Rev-erbα) in the liver and heart of rats after the feeding and light-dark (LD) reversal via a 24-h light period transition. The liver clock was reset quickly within 3 days, while the heart clock needed a longer time course of 5-7 days to be completely re-entrained. Moreover, the reentrainment of Per1 and Per2 in the liver clock was more rapid than that of the other four clock genes, suggesting the important role of these two clock genes in initiating the circadian resetting of the hepatic clock. However, the resetting rates of these two clock genes were as similar as the others in the heart clock. Therefore, the resetting mechanisms underlining these two peripheral clocks may be totally distinct. Furthermore, the reentrainment of the liver and heart clocks were relatively lengthened after the feeding and LD reversal via a light period transition compared to a dark period transition, suggesting a simultaneous shift of feeding schedule and the LD cycle may facilitate the circadian resetting in rats.

PSVI-1 Effect of Light Regiment on Farrowing Performance in Sows

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 220-220
Author(s):  
Shelby A McLoda ◽  
Nichole C Anderson ◽  
Drew W Lugar
Keyword(s):  
Video Recording ◽  
Total Duration ◽  
Interval Number ◽  
Statistical Analyses ◽  
Experimental Unit ◽  
Due Date ◽  
Dark Cycle ◽  
Indirect Measure ◽  
The U.S ◽  
Effect Of Light

Abstract The purpose of this study was to investigate the effects of light on farrowing performance in sows. Thirty sows were moved to the farrowing unit at d 110 of gestation and were assigned one of two treatments: 12 h light/dark cycle (Dark) or 24 h light (Light). Treatments were initiated upon entry into the farrowing unit until completion of farrowing was confirmed. For Dark sows, the farrowing crates were structured with light blocking tarps that were lowered at 1900 hr and raised at 0700 hr daily. Video recording devices were installed above all sows and continuous video was recorded from initiation of the treatments until farrowing was complete. Data collected included duration of farrowing, birthing interval, number of stillborn piglets as an indirect measure of dystocia, total born, and liveborn piglets. All statistical analyses were performed using the mixed procedure of SAS, where the experimental unit was individual sow. Funding for this project was provided by the National Pork Checkoff and the U.S. Pork Center of Excellence. Dark sows were more likely to give birth closer to their due date compared to Light sows (1.34 vs. 2.16 ± 0.24 days relative to a 115-day due date, respectively; P = 0.02). Total duration of parturition did not differ between treatments (P = 0.56). Number of liveborn piglets between treatments did not differ (P = 0.68), however the number of stillborn piglets between treatments was different (P = 0.02), where Dark sows had a higher incidence of stillborn piglets compared to Light sows (1.52 vs. 0.65 ± 0.25 stillborn piglets/litter, respectively). The interval between piglets did not differ between treatments (P = 0.93). It is hypothesized that the effects on due date and increased incidence of stillborn piglets was caused by increased stress due to visual isolation in the Dark sows.

scholarly journals Light represses transcription of asparagine synthetase genes in photosynthetic and nonphotosynthetic organs of plants.

1991 ◽  
Vol 11 (10) ◽  
pp. 4966-4972 ◽  
Author(s):  
F Y Tsai ◽  
G Coruzzi
Keyword(s):  
Gene Expression ◽  
Direct Effect ◽  
Transcriptional Repression ◽  
Time Course ◽  
Nicotiana Plumbaginifolia ◽  
Asparagine Synthetase ◽  
General Phenomenon ◽  
Dark Cycle ◽  
Normal Light ◽  
Effect Of Light

Asparagine synthetase (AS) mRNA in Pisum sativum accumulates preferentially in plants grown in the dark. Nuclear run-on experiments demonstrate that expression of both the AS1 and AS2 genes is negatively regulated by light at the level of transcription. A decrease in the transcriptional rate of the AS1 gene can be detected as early as 20 min after exposure to light. Time course experiments reveal that the levels of AS mRNA fluctuate dramatically during a "normal" light/dark cycle. This is due to a direct effect of light and not to changes associated with circadian rhythm. A novel finding is that the light-repressed expression of the AS1 gene is as dramatic in nonphotosynthetic organs such as roots as it is in leaves. Experiments demonstrate that the small amount of light which passes through the soil is sufficient to repress AS1 expression in roots, indicating that light has a direct effect on AS1 gene expression in roots. The negative regulation of AS gene expression by light was shown to be a general phenomenon in plants which also occurs in nonlegumes such as Nicotiana plumbaginifolia and Nicotiana tabacum. Thus, the AS genes can serve as a model with which to dissect the molecular basis for light-regulated transcriptional repression in plants.

Effect of Light/Dark Cycle on Bacterial Hydrogen Production by Rhodobacter sphaeroides RV

2000 ◽  
Vol 84-86 (1-9) ◽  
pp. 431-440 ◽  
Author(s):  
Tatsuki Wakayama ◽  
Eiju Nakada ◽  
Yasuo Asada ◽  
Jun Miyake
Keyword(s):  
Hydrogen Production ◽  
Rhodobacter Sphaeroides ◽  
Dark Cycle ◽  
Effect Of Light

The effect of light:dark cycles of medium frequency on photosynthesis by Chlorella vulgaris and the implications for waste stabilisation pond design and performance

2003 ◽  
Vol 48 (2) ◽  
pp. 69-74 ◽  
Author(s):  
I.A.J. Ratchford ◽  
H.J. Fallowfield
Keyword(s):  
Oxygen Evolution ◽  
Chlorella Vulgaris ◽  
Oxygen Electrode ◽  
Photon Flux ◽  
Photon Flux Density ◽  
Dark Cycle ◽  
Cycle Times ◽  
Total Light ◽  
And Performance ◽  
Effect Of Light

The effect of light/dark (L:D) cycle times on the recovery from photoinhibition of green micro-alga Chlorella vulgaris (CCAP211/11c) and the cyanobacterium Synechococcus (CCAP1479/5) was investigated using an irradiated, temperature controlled oxygen electrode. The onset of photoinhibition in both organisms occurred at irradiances > 300 mmol m-2s-1 at temperatures >15°C. Light/dark cycle times were controlled independently using a relay timer and shutter placed between the quartz iodide light source and the oxygen electrode chamber. Oxygen evolution decreased rapidly when cells were continuously irradiated at 300, 500 and 750 mmol m-2s-1. However, Chlorella cells irradiated at 300, 500 and 750 mmol m-2s-1 on a L:D cycle of 60s:20s, 30s:60s and 60s:120s respectively, maintained a constant rate of oxygen evolution over a 24 h incubation period. Exposure time to a given incident irradiance rather than the total light dose received appeared to determine the effect of light/dark cycle times on photosynthesis. A relationship was established between L:D ratio required to maintain constant oxygen production and incident photon flux density. The results suggest that the adverse effects of high irradiances on algae near the surface of a stratified waste stabilisation pond might be ameliorated by controlled mixing of algal cells through the depth of the pond.

scholarly journals Effect of Light/Dark Cycle on Photosynthetic Pathway Switching and CO2 Absorption in Two Dendrobium Species

2019 ◽  
Vol 10 ◽  
Author(s):  
Yongsan Cheng ◽  
Dongxian He ◽  
Jie He ◽  
Genhua Niu ◽  
Rongfu Gao
Keyword(s):  
Co2 Absorption ◽  
Photosynthetic Pathway ◽  
Dark Cycle ◽  
Effect Of Light
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