Endogenous Rhythms in the Amounts of 11-cis Retinal in the Compound Eye of Ligia Exotica (Crustacea, Isopoda)

1992 ◽  
Vol 167 (1) ◽  
pp. 39-46 ◽  
Author(s):  
TAKAHIKO HARIYAMA ◽  
YASUO TSUKAHARA
Keyword(s):  
Visual Pigment ◽  
Compound Eye ◽  
Morphological Changes ◽  
Clear Correlation ◽  
Average Amount ◽  
Dark Cycle ◽  
Continuous Darkness ◽  
Endogenous Rhythms ◽  
Retinyl Ester ◽  
Subjective Night

The volume of the rhabdom of Ligia exotica changes diurnally, with the rhythm persisting autogenically in continuous darkness. The morphological changes are accompanied by variations in the amounts of the different chromophores making up the visual pigment. The amount of 11-cis retinal was found to be high at night (26.2±3.5pmol per eye) and low during the day (10.9±2.6pmol per eye) and to display an endogenous rhythm. At dawn and dusk, the amount was 19.1±1.2pmol. This rhythmicity persisted in continuous darkness, although the average amount of 11-cis retinal present gradually increased. In the case of all-trans retinal, changes in the amount were rhythmic in light-dark conditions. The amount of all-trans retinal present in the eye increased shortly after the onset of light and decreased soon after the end of illumination. There was about twice as much 11-cis retinyl ester as 11-cis retinal in the compound eye of Ligia exotica. Rhythmicity in the amount of 11-cis retinyl ester present during the light-dark cycle was observed, but it was opposite in phase to that of 11-cis retinal. Under conditions of continuous darkness a clear rhythm was not apparent: the amount of 11-cis retinyl ester increased not only during the subjective day but also during the following subjective night. Thus, a clear correlation exists between changes in structural organization of the rhabdom and the amounts of 11-cis retinal present. Both show features of a circadian rhythm.

Control of nitrogen assimilation in Stichococcus bacillaris by growth conditions

1987 ◽  
Vol 65 (3) ◽  
pp. 432-437 ◽  
Author(s):  
Iftikhar Ahmad ◽  
Johan A. Hellebust
Keyword(s):  
Glutamine Synthetase ◽  
Nitrogen Assimilation ◽  
Continuous Light ◽  
Synthetase Activity ◽  
Glutamine Synthetase Activity ◽  
Dark Cycle ◽  
Continuous Darkness ◽  
Cell Carbon ◽  
Stichococcus Bacillaris ◽  
Mixotrophic Conditions

Stichococcus bacillaris Naeg. (Chlorophyceae) grown on a 12 h light: 12 h dark cycle divides synchronously under photoautotrophic conditions and essentially nonsynchronously under mixotrophic conditions. Photoassimilation of carbon under photoautotrophic conditions was followed by a decline in cell carbon content during the dark period, whereas under mixotrophic conditions cell carbon increased throughout the light–dark cycle. The rates of nitrogen assimilation by cultures grown on either nitrate or ammonium declined sharply during the dark, and these declines were most pronounced under photoautotrophic conditions. Photoautotrophic cells synthesized glutamine synthetase and NADPH – glutamate dehydrogenase (GDH) exclusively in the light, whereas in mixotrophic cells about 20% of the total synthesis of these enzymes during one light–dark cycle occurred in the dark. NADH–GDH was synthesized almost continuously over the entire light–dark cycle. In the dark, both under photoautotrophic and mixotrophic conditions, the alga contained more than 50% of glutamine synthetase in an inactive form, which was reactivated in vitro in the presence of mercaptoethanol and in vivo after returning the cultures to the light. The thermal stability of glutamine synthetase activity was less in light-harvested cells than in dark-harvested cells. The inactivation of glutamine synthetase did not occur in cultures growing either heterotrophically in continuous darkness or photoautotrophically in continuous light. This enzyme appears to be under thiol control only in cells grown under alternating light–dark conditions, irrespective of whether this light regime results in synchronous cell division or not.

scholarly journals Two visual pigment opsins, one expressed in the dorsal region and another in the dorsal and the ventral regions, of the compound eye of a dragonfly,Sympetrum frequens

1996 ◽  
Vol 2 (3) ◽  
pp. 209-209 ◽  
Author(s):  
Kentaro Arikawa ◽  
Koichi Ozaki ◽  
Takanari Tsuda ◽  
Junko Kitamoto ◽  
Yuji Mishina
Keyword(s):  
Visual Pigment ◽  
Compound Eye ◽  
Dorsal Region ◽  
Sympetrum Frequens

scholarly journals The role of retinal photoisomerase in the visual cycle of the honeybee.

1991 ◽  
Vol 97 (1) ◽  
pp. 143-165 ◽  
Author(s):  
W C Smith ◽  
T H Goldsmith
Keyword(s):  
Visual Pigment ◽  
Compound Eye ◽  
Rod Outer Segments ◽  
Visual Cycle ◽  
In Vitro Techniques ◽  
The Third ◽  
Isomerization Processes

The compound eye of the honeybee has previously been shown to contain a soluble retinal photoisomerase which, in vitro, is able to catalyze stereospecifically the photoconversion of all-trans retinal to 11-cis retinal. In this study we combine in vivo and in vitro techniques to demonstrate how the retinal photoisomerase is involved in the visual cycle, creating 11-cis retinal for the generation of visual pigment. Honeybees have approximately 2.5 pmol/eye of retinal associated with visual pigments, but larger amounts (4-12 pmol/eye) of both retinal and retinol bound to soluble proteins. When bees are dark adapted for 24 h or longer, greater than 80% of the endogenous retinal, mostly in the all-trans configuration, is associated with the retinal photoisomerase. On exposure to blue light the retinal is isomerized to 11-cis, which makes it available to an alcohol dehydrogenase. Most of it is then reduced to 11-cis retinol. The retinol is not esterified and remains associated with a soluble protein, serving as a reservoir of 11-cis retinoid available for renewal of visual pigment. Alternatively, 11-cis retinal can be transferred directly to opsin to regenerate rhodopsin, as shown by synthesis of rhodopsin in bleached frog rod outer segments. This retinaldehyde cycle from the honeybee is the third to be described. It appears very similar to the system in another group of arthropods, flies, and differs from the isomerization processes in vertebrates and cephalopod mollusks.

scholarly journals Ultradian regulation of rest and activity bouts in mice

2019 ◽  
Author(s):  
Bharath Ananthasubramaniam ◽  
Johanna H. Meijer
Keyword(s):  
Average Length ◽  
Behavioral Activity ◽  
Time Interval ◽  
Behavioral State ◽  
Infrared Sensors ◽  
Continuous Darkness ◽  
Subjective Night ◽  
Activity Bout ◽  
Central Pacemaker ◽  
Light Input

AbstractThe suprachiasmatic nucleus (SCN), which serves as the central pacemaker in mammals, regulates the 24-hour rhythm in behavioral activity. However, it is currently unclear whether and how bouts of activity and rest are regulated within the 24-hour cycle (i.e., over ultradian time scales). Therefore, we used passive infrared sensors to measure behavior in mice housed under either a light-dark (LD) cycle or continuous darkness (DD). We found that a probabilistic Markov model captures the ultradian changes in the behavioral state over a 24-hour cycle. In this model, the animal’s behavioral state in the next time interval is determined solely by the animal’s current behavioral state and by the “toss” of a proverbial “biased coin”. We found that the bias of this “coin” is regulated by light input and by the phase of the clock. Moreover, the bias of this “coin” for an animal is related to the average length of rest and activity bouts in that animal. In LD conditions, the average length of rest bouts was greater during the day compared to during the night, whereas the average length of activity bouts was greater during the night compared to during the day. Importantly, we also found that day-night changes in the rest bout lengths were significantly greater than day-night changes in the activity bout lengths. Finally, in DD conditions, the activity and rest bouts also differed between subjective night and subjective day, albeit to a lesser extent compared to LD conditions. The persistent differences in bout length over the circadian cycle following loss of the external LD cycle indicate that the central pacemaker plays a role in regulating rest and activity bouts on an ultradian time scale.

scholarly journals Life after Harvest: Circadian Regulation in Photosynthetic Pigments of Rocket Leaves during Supermarket Storage Affects the Nutritional Quality

Nutrients ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1519
Author(s):  
Lorena Ruiz de Larrinaga ◽  
Victor Resco de Dios ◽  
Dmitri Fabrikov ◽  
José Luis Guil-Guerrero ◽  
José María Becerril ◽  
...  
Keyword(s):  
Nutritional Quality ◽  
Continuous Light ◽  
Continuous Darkness ◽  
Endogenous Rhythms ◽  
Research Perspective ◽  
Nutrition Science ◽  
Light Darkness ◽  
New Research ◽  
Quality Assessments ◽  
First Time

Vegetables, once harvested and stored on supermarket shelves, continue to perform biochemical adjustments due to their modular nature and their ability to retain physiological autonomy. They can live after being harvested. In particular, the content of some essential nutraceuticals, such as carotenoids, can be altered in response to environmental or internal stimuli. Therefore, in the present study, we wondered whether endogenous rhythms continue to operate in commercial vegetables and if so, whether vegetable nutritional quality could be altered by such cycles. Our experimental model consisted of rocket leaves entrained under light/darkness cycles of 12/12 h over 3 days, and then we examined free-run oscillations for 2 days under continuous light or continuous darkness, which led to chlorophyll and carotenoid oscillations in both constant conditions. Given the importance of preserving food quality, the existence of such internal rhythms during continuous conditions may open new research perspective in nutrition science. However, while chromatographic techniques employed to determine pigment composition are accurate, they are also time-consuming and expensive. Here we propose for the first time an alternative method to estimate pigment content and the nutritional quality by the use of non-destructive and in situ optical techniques. These results are promising for nutritional quality assessments.

Daily hypothermia and torpor in a tropical primate: synchronization by 24-h light-dark cycle

2001 ◽  
Vol 281 (6) ◽  
pp. R1925-R1933 ◽  
Author(s):  
M. Perret ◽  
F. Aujard
Keyword(s):  
Locomotor Activity ◽  
Fixed Time ◽  
Temporal Organization ◽  
Physiological Changes ◽  
Dark Cycle ◽  
Subjective Night ◽  
Free Running ◽  
Rapid Drop ◽  
Gray Mouse Lemur ◽  
Short Days

To study the temporal organization of daily hypothermia and torpor in a nocturnal Malagasy primate, the gray mouse lemur, body temperature (Tb) and locomotor activity were recorded using telemetry on 39 males held in 24-h light-dark cycles of different photoperiods. Under free-running condition, the circadian Tb and locomotor activity rhythms had a period shorter than 24 h. Circadian daily hypothermia started by a rapid drop in Tb (0.24°C/10 min) at the end of subjective night (13 h 25 ± 20 min) and was characterized by minimal Tb values 3 h 20 ± 5 min later. Spontaneous arousal from daily hypothermia occurred at a fixed time (6 h 05 ± 15 min, n = 7) after the beginning of subjective day. In animals exposed to 24-h light-dark cycles with night duration varying from 10 to 14 h, locomotor activity was strictly restricted to dark time, but the temporal organization of daily hypothermia was not modified, although changes in amplitude of Tb rhythm were observed. Daily hypothermia was directly induced by light and lasted 5 h 10 ± 10 min, with minimal Tb values 3 h 30 ± 30 min ( n = 28) after lights on, on condition that nighttime did not exceed the duration of subjective night. However, in animals exposed to 24-h light-dark cycles with night duration varying from 10 to 5 h, the limit of induction of daily hypothermia by light was ∼9 h after the beginning of night. Finally, under short days (14:10-h light-dark cycle), long bouts (6 h 50 ± 40 min) of actual torpor (minimum Tb 27.6 ± 0.9°C) were observed and would involve mechanisms depending on physiological changes induced by short day exposure.

Visual receptor cycle in normal and period mutant Drosophila: Microspectrophotometry, electrophysiology, and ultrastructural morphometry

1992 ◽  
Vol 9 (2) ◽  
pp. 125-135 ◽  
Author(s):  
De-Mao Chen ◽  
J. Scott Christianson ◽  
Randall J. Sapp ◽  
William S. Stark
Keyword(s):  
Circadian Rhythm ◽  
Visual Pigment ◽  
Constant Darkness ◽  
Wild Type ◽  
Dark Cycle ◽  
Light Onset ◽  
Cross Sectional ◽  
Ultrastructural Morphometry ◽  
Em Morphometry ◽  
Visual Receptor

AbstractVisual pigment, sensitivity, and rhabdomere size were measured throughout a 12-h light/12-h dark cycle in Drosophila. Visual pigment and sensitivity were measured during subsequent constant darkness [dark/dark (D/D)]. MSP (microspectrophotometry) and the ERG (electroretinogram) revealed a cycling of visual pigment and sensitivity, respectively. A visual pigment decrease of 40% was noted at 4 h after light onset that recovered 2–4 h later in white-eyed (otherwise wild-type, w per+) flies. The ERG sensitivity [in w per+ flies in light/dark (L/D)] decreased by 75% at 4 h after light onset, more than expected if mediated by visual pigment (MSP) changes alone. ERG sensitivity begins decreasing 8 h before light onset while decreases in visual pigment begin 2 h after light onset. These cycles continue in constant darkness (D/D), suggesting a circadian rhythm. White-eyed period (per) mutants show similar cycles of visual pigment level and sensitivity in L/D; per's alterations, if any on the D/D cycles were subtle. The cross-sectional areas of rhabdomeres in w per+ were measured using electron micrographic (EM) morphometry. Area changed little through the L/D cycle.

scholarly journals Electroretinogram Characteristics and the Spectral Mechanisms of the Median Ocellus and the Lateral Eye in Limulus polyphemus

1967 ◽  
Vol 50 (9) ◽  
pp. 2267-2287 ◽  
Author(s):  
Robert M. Chapman ◽  
Abner B. Lall
Keyword(s):  
Spectral Sensitivity ◽  
Visual Pigment ◽  
Light Adaptation ◽  
Compound Eye ◽  
State Level ◽  
Chromatic Adaptation ◽  
Absorption Bands ◽  
Energy Functions ◽  
Lateral Eye ◽  
Median Ocellus

Electrical responses (ERG) to light flashes of various wavelengths and energies were obtained from the dorsal median ocellus and lateral compound eye of Limulus under dark and chromatic light adaptation. Spectral mechanisms were studied by analyzing (a) response waveforms, e.g. response area, rise, and fall times as functions of amplitude, (b) slopes of amplitude-energy functions, and (c) spectral sensitivity functions obtained by the criterion amplitude method. The data for a single spectral mechanism in the lateral eye are (a) response waveforms independent of wavelength, (b) same slope for response-energy functions at all wavelengths, (c) a spectral sensitivity function with a single maximum near 520 mµ, and (d) spectral sensitivity invariance in chromatic adaptation experiments. The data for two spectral mechanisms in the median ocellus are (a) two waveform characteristics depending on wavelength, (b) slopes of response-energy functions steeper for short than for long wavelengths, (c) two spectral sensitivity peaks (360 and 530–535 mµ) when dark-adapted, and (d) selective depression of either spectral sensitivity peak by appropriate chromatic adaptation. The ocellus is 200–320 times more sensitive to UV than to visible light. Both UV and green spectral sensitivity curves agree with Dartnall's nomogram. The hypothesis is favored that the ocellus contains two visual pigments each in a different type of receptor, rather than (a) various absorption bands of a single visual pigment, (b) single visual pigment and a chromatic mask, or (c) fluorescence. With long duration light stimuli a steady-state level followed the transient peak in the ERG from both types of eyes.

Packaging of rhodopsin and porphyropsin in the compound eye of the crayfish

1993 ◽  
Vol 10 (2) ◽  
pp. 193-202 ◽  
Author(s):  
Joel Zeiger ◽  
Timothy H. Goldsmith
Keyword(s):  
Visual Pigment ◽  
Regional Variation ◽  
Compound Eye ◽  
Procambarus Clarkii ◽  
Difference Spectra ◽  
Retinular Cells ◽  
Different Levels

AbstractThe distribution of 3-dehydroretinal (Ral2) in dorsal, middle, and ventral slices of eyes of the crayfish Procambarus clarkii was examined by HPLC. No pronounced differences were found. Similar results were obtained when the eyes were cut into anterior, intermediate, and posterior portions.Dichroic difference spectra were measured in single halves of microvillar layers of isolated rhabdoms and the proportions of rhodopsin (P1) and porphyropsin (P2) estimated by comparison with computer-generated mixtures of these pigments, whose spectra are known from previous work. The fraction of visual pigment that is porphyropsin appears to be uniform throughout individual retinular cells and among the retinular cells of individual rhabdoms, but various substantially among different rhabdoms from the same eye.The interommatidial variation in the amount of P2 greatly exceeds the gross regional variation in Ral2. This means there is an intermingling of ommatidia with different levels of P2. The variability in P2 among ommatidia is not likely to have important implications for the vision of the crayfish but suggests that in the metabolism of retinoids, individual ommatidia are quasi-independent metabolic units. The results are compatible with a single opsin for both crayfish rhodopsin and porphyropsin.

Entrainment in calorie-restricted mice: conflicting zeitgebers and free-running conditions

1998 ◽  
Vol 274 (6) ◽  
pp. R1751-R1761 ◽  
Author(s):  
Etienne Challet ◽  
Leah C. Solberg ◽  
Fred W. Turek
Keyword(s):  
Locomotor Activity ◽  
Calorie Restriction ◽  
Phase Advance ◽  
Constant Darkness ◽  
Dark Cycle ◽  
Subjective Night ◽  
Ad Libitum ◽  
Anticipatory Activity ◽  
Time Of Feeding ◽  
Nocturnal Period

Phase-shifting effects of timed calorie restriction were investigated in mice during exposure to a 12:12-h light-dark cycle. Food-anticipatory activity (FAA), the output of a food-entrainable pacemaker, was expressed before the time of feeding whether mice received daily hypocaloric food (3.3 g of chow/day) or normocaloric food (5 g of chow/day) at zeitgeber time (ZT) 2 (ZT12 = lights off). Subsequently, mice were placed in constant darkness and fed ad libitum. The onset of the nocturnal period of locomotor activity was phase advanced by 1 h in calorie-restricted mice compared with normocalorie-fed controls. The phase advance still occurred when FAA was prevented by restraining calorie-restricted mice. Giving hypocaloric food at ZT2, ZT10, ZT14, or ZT22 phase advanced the nocturnal pattern of activity by 1, 3, 1, and 1 h, respectively. After transfer to constant darkness, FAA free ran in parallel with the normal nocturnal period of locomotor activity. A light pulse during the early subjective night phase delayed both components. These results indicate that 1) timed calorie restriction under a light-dark cycle can phase advance the light-entrainable pacemaker with a phase-dependent magnitude, 2) FAA feedback is not crucial for the observed phase advance, and 3) the light-entrainable pacemaker may control the period of the food-entrainable pacemaker in mice fed ad libitum.

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