Continuous light or darkness and circadian periodic mitosis and metabolism in C and D8 mice

1961 ◽  
Vol 201 (2) ◽  
pp. 227-230 ◽  
Author(s):  
Franz Halberg ◽  
Cyrus P. Barnum
Keyword(s):  
Cell Division ◽  
Circadian Rhythms ◽  
Deoxyribonucleic Acid ◽  
Acid Metabolism ◽  
Specific Activity ◽  
Continuous Light ◽  
Liver Parenchyma ◽  
Constant Light ◽  
Constant Darkness ◽  
Spot Check

In immature C mice exposed first to alternating 12 hr of light and 12 hr of darkness (LD), and maintained thereafter in constant darkness for several days, the circadian rhythms in hepatic and pinnal mitosis are demonstrable by spot checks made at the approximate times of LD-synchronized peak and trough. Spot checks at same times in mice of same stock and age, kept for several days in constant light, reveal the cell division rhythm of liver parenchyma, but not that of pinnal epidermis. In immature D8 mice kept for several days in constant darkness, rhythms in hepatic mitosis, phospholipid, ribonucleic and deoxyribonucleic acid metabolism persist, while cell division rhythm in ear pinna of same animals is not detectable with the particular spot check used. In mice of same stock and age, on the 4th day in constant light, a significant rhythm persists in the relative specific activity of the hepatic phospholipid; timing of this metabolic cellular rhythm is drastically desynchronized from the reference standard of a 24-hr clock. Data reveal persistence of some mitotic and metabolic circadian rhythms under conditions studied, with phase drifts or phase shifts of these rhythms occurring both in relation to the 24-hr clock and among the rhythms themselves. These changes in external and internal timing of a circadian system are more extensive in constant light than in constant darkness.

Photic Response Parameters of Circadian Rhythms in The Spinifex Hopping Mouse, Notomys alexis.

1996 ◽  
Vol 19 (1) ◽  
pp. 11
Author(s):  
A.J.P. Francis ◽  
G.J. Coleman
Keyword(s):  
Circadian Rhythms ◽  
Phase Relations ◽  
Constant Light ◽  
Constant Darkness ◽  
Biological Clocks ◽  
Circadian Activity ◽  
Activity Rhythms ◽  
Controlled Conditions ◽  
Australian Native Rodent ◽  
Photic Response

Circadian rhythms are generated endogenously by biological clocks or 'pacemakers', which are responsive to significant environmental stimuli termed zeitgebers. Interactions between pacemakers and zeitgebers provide the basis for synchronisation by light-dark (LD) cycles, and the characteristics of each of these elements determines the phase-relations maintained between an animal's circadian activity rhythms and the natural temporal environment. We report here the basic photic response parameters for an Australian native rodent, Notomys alexis. Under controlled conditions of constant darkness or constant light, N. alexis were found to 'free-run', and with periods different from 24 hours. Under LD cycles N. alexis were strictly nocturnal although, compared to other rodents, entrainment to LD cycles was relatively unstable. This may indicate that N. alexis are not strongly dependent on the LD cycle as a zeitgeber.

scholarly journals INFLUENCE OF LIGHT ON THE GROWTH AND MALIGNANCY OF A TRANSPLANTABLE NEOPLASM OF THE RABBIT

1927 ◽  
Vol 45 (4) ◽  
pp. 727-751 ◽  
Author(s):  
Louise Pearce ◽  
Wade H. Brown
Keyword(s):  
Bone Metastases ◽  
Experimental Evidence ◽  
Malignant Disease ◽  
External Factor ◽  
Wave Length ◽  
Continuous Light ◽  
Constant Light ◽  
Constant Darkness ◽  
Special Character

Experiments are reported in which an environment of constant and continuous light with a wave-length of from 3022 to 5790 Ångström units, supplied by mercury arcs in crown glass, and of constant darkness, have influenced the course and character of a malignant disease of rabbits induced by a transplantable neoplasm. Under the influence of constant light the level of malignancy was lower than in control animals living under ordinary conditions of diffused sunlight. Under the influence of constant darkness the level of malignancy was somewhat lower than in control animals but the effect of this environment was modified by the special character of the disease prevailing at this time. The incidence of bone metastases was unusually high, but it was greatly increased in the rabbits kept in constant darkness. These observations furnish experimental evidence in support of the belief that there is a correlation between the external factor of light and the manifestations of an experimental malignant disease.

scholarly journals The effects of Levilactobacillus brevis on the physiological parameters and gut microbiota composition of rats subjected to desynchronosis

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Evgenii I. Olekhnovich ◽  
Ekaterina G. Batotsyrenova ◽  
Roman A. Yunes ◽  
Vadim A. Kashuro ◽  
Elena U. Poluektova ◽  
...  
Keyword(s):  
Circadian Rhythms ◽  
Gut Microbiota ◽  
Relative Abundance ◽  
Reduced Glutathione ◽  
Physiological Parameters ◽  
Male Rats ◽  
Constant Light ◽  
Constant Darkness ◽  
Microbiota Composition ◽  
Gut Microbiota Composition

Abstract Background All living organisms have developed during evolution complex time-keeping biological clocks that allowed them to stay attuned to their environments. Circadian rhythms cycle on a near 24 h clock. These encompass a variety of changes in the body ranging from blood hormone levels to metabolism, to the gut microbiota composition and others. The gut microbiota, in return, influences the host stress response and the physiological changes associated with it, which makes it an important determinant of health. Lactobacilli are traditionally consumed for their prophylactic and therapeutic benefits against various diseases, namely, the inflammatory bowel syndrome, and even emerged recently as promising psychobiotics. However, the potential role of lactobacilli in the normalization of circadian rhythms has not been addressed. Results Two-month-old male rats were randomly divided into three groups and housed under three different light/dark cycles for three months: natural light, constant light and constant darkness. The strain Levilactobacillus brevis 47f was administered to rats at a dose of 0.5 ml per rat for one month and The rats were observed for the following two months. As a result, we identified the biomarkers associated with intake of L. brevis 47f. Changing the light regime for three months depleted the reserves of the main buffer in the cell—reduced glutathione. Intake of L. brevis 47f for 30 days restored cellular reserves of reduced glutathione and promoted redox balance. Our results indicate that the levels of urinary catecholamines correlated with light/dark cycles and were influenced by intake of L. brevis 47f. The gut microbiota of rats was also influenced by these factors. L. brevis 47f intake was associated with an increase in the relative abundance of Faecalibacterium and Roseburia and a decrease in the relative abundance of Prevotella and Bacteroides. Conclusions The results of this study show that oral administration of L. brevis 47f, for one month, to rats housed under abnormal lightning conditions (constant light or constant darkness) normalized their physiological parameters and promoted the gut microbiome's balance.

scholarly journals Alterations in Nuclear Ribonucleic Acid Metabolism Induced by Kinetin

1957 ◽  
Vol 3 (1) ◽  
pp. 129-132 ◽  
Author(s):  
Ruth Guttman
Keyword(s):  
Cell Division ◽  
Ribonucleic Acid ◽  
Deoxyribonucleic Acid ◽  
Acid Metabolism ◽  
Root Cells ◽  
Onion Root ◽  
Azure B ◽  
Division Factor

Removal of deoxyribonucleic acid from meristematic onion root cells grown in solutions of kinetin, followed by metachromatic staining in azure B bromide, indicated the presence of appreciable amounts of ribonucleic acid in nuclei exposed to the cell division factor.

scholarly journals INFLUENCE OF LIGHT ON THE GROWTH AND MALIGNANCY OF A TRANSPLANTABLE NEOPLASM OF THE RABBIT

1927 ◽  
Vol 45 (3) ◽  
pp. 483-496 ◽  
Author(s):  
Louise Pearce ◽  
C. M. Van Allen
Keyword(s):  
Experimental Evidence ◽  
Malignant Disease ◽  
External Factor ◽  
Continuous Light ◽  
Ultra Violet ◽  
The Other ◽  
Constant Light ◽  
Constant Darkness ◽  
Light Conditions ◽  
The One

An experiment is reported in which an environment of constant and continuous light excluding the shorter ultra-violet rays, and one of constant darkness, have influenced the course and character of a malignant disease of rabbits induced by a transplantable neoplasm. Under the influence of constant light the level of malignancy was observed to be low; under the influence of constant darkness the level of malignancy was somewhat lower than in the control animals living under ordinary indoor light conditions, but the level was not as low as among the animals constantly illuminated. These observations furnish experimental evidence in support of the idea that there is a correlation between the external factor of light on the one hand and the manifestations of an experimental malignant disease on the other.

P32 uptake in DNA nucleotides after partial hepatectomy and after unilateral nephrectomy

1961 ◽  
Vol 201 (3) ◽  
pp. 523-525 ◽  
Author(s):  
David P. Simpson
Keyword(s):  
Cell Division ◽  
Dna Synthesis ◽  
Partial Hepatectomy ◽  
Intraperitoneal Injection ◽  
Deoxyribonucleic Acid ◽  
Specific Activity ◽  
Unilateral Nephrectomy ◽  
Data Support ◽  
Organ Specific

Deoxyribonucleic acid (DNA) synthesis as reflected in the specific activity of DNA nucleotides 12 hr after intraperitoneal injection of P32 has been compared after partial hepatectomy and after unilateral nephrectomy. Thirty-six hours after partial hepatectomy, a maximum uptake 11-fold greater than in controls was found. The maximum after unilateral nephrectomy occurred 48 hr after operation and was twofold greater than in controls. Subsequent to these maxima, P32 uptake declined after both operations to a minimum eight days postoperatively which was followed by a second rise on the 9th day. These data support the concept that similar basic mechanisms regulate growth and cell division after the two types of operation. In another experiment, P32 uptake in kidney DNA nucleotides showed no increase after partial hepatectomy; this lends weight to the hypothesis that the mitosis-stimulating substances which appear in the serum after partial hepatectomy and after unilateral nephrectomy are organ specific.

EFFECTS OF PINEALECTOMY, CONSTANT LIGHT AND DARKNESS ON GROWTH HORMONE LEVELS IN THE PITUITARY AND PLASMA OF THE RAT

1972 ◽  
Vol 53 (2) ◽  
pp. 289-293 ◽  
Author(s):  
R. RELKIN
Keyword(s):  
Growth Hormone ◽  
Body Weight ◽  
Plasma Concentrations ◽  
Continuous Light ◽  
Tail Length ◽  
Male Rats ◽  
Constant Light ◽  
Constant Darkness ◽  
Continuous Darkness ◽  
Plasma Gh

SUMMARY The effects of constant light, constant darkness, and diurnal lighting, in combination with pinealectomy or sham pinealectomy, on pituitary and plasma concentrations of radio-immunoassayable growth hormone (GH) were investigated in 23- to 24-day-old male rats. In addition, the effects on pituitary, accessory sex organ, testes, adrenal and body weights, as well as tail length, were measured. Three days after operation random groups of pinealectomized and sham-pinealectomized animals were placed in either continuous light, continuous darkness or diurnal light, and killed 28–29 days later. Analysis of the results revealed that the sham-pinealectomized group exposed to constant darkness differed from the other five groups by showing lower pituitary and plasma GH concentrations, body weight, tail length and accessory sex organ weight relative to body weight and testes weight. No statistically significant differences were found in pituitary or adrenal weights. It is concluded that increased pineal function occurring in darkness probably inhibits secretion of GH releasing factor, decreasing pituitary synthesis and release of GH.

Localization of the clock controlling circadian rhythms in the first neuropile of the optic lobe in the housefly

2001 ◽  
Vol 204 (19) ◽  
pp. 3303-3310
Author(s):  
Monika Bałys ◽  
Elżbieta Pyza
Keyword(s):  
Circadian Rhythms ◽  
Musca Domestica ◽  
Compound Eye ◽  
Optic Lobe ◽  
Continuous Light ◽  
Constant Darkness ◽  
Cross Sectional ◽  
Circadian Oscillators ◽  
L1 And L2 ◽  
The Brain

SUMMARYThe visual system of a fly expresses several circadian rhythms that have been detected in the photoreceptors of the compound eye and in the first neuropile, the lamina, of the underlying optic lobe. In the lamina, axons of two classes of interneuron, L1 and L2, exhibit cyclical size changes, swelling by day and shrinking by night. These rhythmic size changes may be generated by circadian oscillators located inside and/or outside the optic lobe. To localize such oscillators, we have examined changes in the axonal cross-sectional areas of L1 and L2 within the lamina of the housefly (Musca domestica) under conditions of 12 h of light and 12 h of darkness (LD12:12), constant darkness (DD) or continuous light (LL) 24 h after the medulla was severed from the rest of the brain. After the lesion, the axon size changes of L1 and L2 were maintained only in LD conditions, but were weaker than in control flies. In DD and LL conditions, they were eliminated. This indicates that circadian rhythms in the lamina of a fly are generated central to the lamina and medulla neuropiles of the optic lobe. Cyclical changes of light and darkness in LD conditions are still able, however, to induce a weak daily rhythm in the axon sizes of L1 and L2.

scholarly journals Identification of circadian rhythms in Nannochloropsis species using bioluminescence reporter lines

2019 ◽  
Author(s):  
Eric Poliner ◽  
Cameron Cummings ◽  
Linsey Newton ◽  
Eva M. Farré
Keyword(s):  
Cell Division ◽  
Circadian Rhythms ◽  
Molecular Mechanisms ◽  
Environmental Changes ◽  
Firefly Luciferase ◽  
Constant Light ◽  
Future Studies ◽  
Circadian Oscillators ◽  
Free Running

SummaryCircadian clocks allow organisms to predict environmental changes caused by the rotation of the Earth. Although circadian rhythms are widespread among different taxa, the core components of circadian oscillators are not conserved and differ between bacteria, plants, animals and fungi. Stramenopiles are a large group of organisms in which circadian rhythms have been only poorly characterized and no clock components have been identified. We have investigated cell division and molecular rhythms in Nannochloropsis species. In the four strains tested, cell division occurred principally during the night period under diel conditions, however, rhythms dampened within 2-3 days after transfer to constant light. We developed firefly luciferase reporters for long-term monitoring of in vivo transcriptional rhythms in two Nannochlropsis species, N. oceanica CCMP1779 and N. salina CCMP537. The reporter lines express free-running bioluminescence rhythms with periods of ~21-31 h that dampen within ~3-4 days under constant light. Using different entrainment regimes, we demonstrate that these rhythms are regulated by a circadian-type oscillator. In addition, the phase of free-running luminescence rhythms can be modulated pharmacologically using a CK1 ε/δ inhibitor, suggesting a role of this kinase in the Nannochloropsis clock. Together with the molecular and genomic tools available for Nannochloropsis species, these reporter lines represent an excellent system for future studies on the molecular mechanisms of stramenopile circadian oscillators.Significance statementStramenopiles are a large and diverse line of eukaryotes in which circadian rhythms have been only poorly characterized and no clock components have been identified. We have developed bioluminescence reporter lines in Nannochloropsis species and provide evidence for the presence of a circadian oscillator in stramenopiles; these lines will serve as tools for future studies to uncover the molecular mechanisms of circadian oscillations in these species.

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