Neural control of glycogen content and its diurnal rhythm in mouse pineal cell.

1977 ◽  
Vol 232 (6) ◽  
pp. E584 ◽  
Author(s):  
T Kachi ◽  
T Ito
Keyword(s):  
Diurnal Rhythm ◽  
Neural Control ◽  
Glycogen Content ◽  
Sympathetic Innervation ◽  
Continuous Light ◽  
Glycogen Metabolism ◽  
Release Of Noradrenaline ◽  
Internal Mechanism ◽  
Dd Mice

In adult male dd mice, possible mechanisms regulating the glycogen content in the pineal cell were investigated by a semiquantitative histochemical method, with particular reference to the role of the sympathetic innervation. Reserpine, superior cervical ganglionectomy (SCGX), or decentralization of the ganglia (DC), as well as continuous light, prevented the nocturnal decrease in the glycogen content, causing a marked increase, and caused a gradual decrease in the size of the pineal cell. In the SCGX or DC group, the glycogen content reached a peak at 2 days and then decreased gradually. The nocturnal decrease was also prevented by propranolol. Noradrenaline caused a marked decrease in the glycogen content. These findings support the hypothesis that the glycogen metabolism and its diurnal rhythm in the pineal cell are regulated by the sympathetic nerve terminals innervating the pineal gland, presumably by the release of noradrenaline. In addition, the nature of the internal mechanism in the organism generating the pineal glycogen rhythm was examined. Light was considered to induce a phase shift in such a mechanism, but reserpine was not.

scholarly journals Identification of the Genes Related to the Glycogen Metabolism in Hyperthermophilic Archaeon, Sulfolobus acidocaldarius

2021 ◽  
Vol 12 ◽  
Author(s):  
Areum Lee ◽  
Eunji Bae ◽  
Jihee Park ◽  
Kyoung-Hwa Choi ◽  
Jaeho Cha
Keyword(s):  
Death Rate ◽  
Deletion Mutant ◽  
Glycogen Content ◽  
Glycogen Metabolism ◽  
Sulfolobus Acidocaldarius ◽  
Growth Phases ◽  
Wild Type ◽  
Promoter Assay ◽  
Branching Points

Glycogen is a polysaccharide that comprises α-1,4-linked glucose backbone and α-1,6-linked glucose polymers at the branching points. It is widely found in organisms ranging from bacteria to eukaryotes. The physiological role of glycogen is not confined to being an energy reservoir and carbon source but varies depending on organisms. Sulfolobus acidocaldarius, a thermoacidophilic archaeon, was observed to accumulate granular glycogen in the cell. However, the role of glycogen and genes that are responsible for glycogen metabolism in S. acidocaldarius has not been identified clearly. The objective of this study is to identify the gene cluster, which is composed of enzymes that are predicted to be involved in the glycogen metabolism, and confirm the role of each of these genes by constructing deletion mutants. This study also compares the glycogen content of mutant and wild type and elucidates the role of glycogen in this archaeon. The glycogen content of S. acidocaldarius MR31, which is used as a parent strain for constructing the deletion mutant in this study, was increased in the early and middle exponential growth phases and decreased during the late exponential and stationary growth phases. The pattern of the accumulated glycogen was independent to the type of supplemented sugar. In the comparison of the glycogen content between the gene deletion mutant and MR31, glycogen synthase (GlgA) and α-amylase (AmyA) were shown to be responsible for the synthesis of glycogen, whereas glycogen debranching enzyme (GlgX) and glucoamylase (Gaa) appeared to affect the degradation of glycogen. The expressions of glgC–gaa–glgX and amyA–glgA were detected by the promoter assay. This result suggests that the gradual decrease of glycogen content in the late exponential and stationary phases occurs due to the increase in the gene expression of glgC–gaa–glgX. When the death rate in nutrient limited condition was compared among the wild type strain, the glycogen deficient strain and the strain with increased glycogen content, the death rate of the glycogen deficient strain was found to be higher than any other strain, thereby suggesting that the glycogen in S. acidocaldarius supports cell maintenance in harsh conditions.

Role of glucocorticoid in the regulation of glycogen metabolism in skeletal muscle

1991 ◽  
Vol 260 (6) ◽  
pp. E927-E932 ◽  
Author(s):  
L. Coderre ◽  
A. K. Srivastava ◽  
J. L. Chiasson
Keyword(s):  
Skeletal Muscle ◽  
Muscle Contraction ◽  
Glycogen Phosphorylase ◽  
Glycogen Content ◽  
Glycogen Synthase ◽  
Glycogen Metabolism ◽  
Activity Ratios ◽  
Resting Muscle ◽  
Glycogen Breakdown

With the use of the hindlimb perfusion technique, the effect of glucocorticoid on the regulation of glycogen metabolism was studied in rat skeletal muscle. Rats were adrenalectomized (ADX) or sham operated (controls) 14 days before the study. The ADX animals were treated with either saline or corticosterone, and the hindlimbs were perfused at rest or during muscle contraction with saline or epinephrine (10(-7) M). In the resting state, the glycogen content was 33.0 +/- 1.9 mumol/g in the controls, and the activity ratios of glycogen phosphorylase (GPase) and glycogen synthase (GSase) were 0.27 +/- 0.03 and 0.15 +/- 0.02, respectively. Epinephrine treatment increased GPase activity (0.78 +/- 0.03) and decreased GSase activity (0.05 +/- 0.01), which resulted in decreased glycogen content (25.7 +/- 0.9 mumol/g; P less than 0.01). Adrenalectomy induced a 35% reduction in glycogen content but had no effect on the activities of basal enzymes. Under these conditions, however, epinephrine had no effect on GPase activity, had a diminished effect on GSase activity (0.11 +/- 0.01), and did not induce further glycogen breakdown. Corticosterone replacement normalized muscle glycogen content in ADX rats as well as the response of the enzymes to epinephrine. Muscle contraction resulted in a decrease in glycogen content (8.9 +/- 1.3 mumol/g) and in GPase activity (0.14 +/- 0.02) and an increase in GSase activity (0.25 +/- 0.01); this was not affected by adrenalectomy nor by epinephrine. In conclusion, these data indicate that glucocorticoid is essential for the effects of epinephrine on GPase activation. on GSase inhibition, and consequently on glycogen breakdown in resting muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Postprandial Glycogen Content Is Increased in the Hepatocytes of Human and Rat Cirrhotic Liver

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 976
Author(s):  
Natalia N. Bezborodkina ◽  
Sergey V. Okovityi ◽  
Boris N. Kudryavtsev
Keyword(s):  
Rat Liver ◽  
Liver Tissue ◽  
Glycogen Content ◽  
Glycogen Synthase ◽  
Fibrous Tissue ◽  
Glycogen Metabolism ◽  
Liver Parenchyma ◽  
Dry Mass ◽  
Cirrhotic Liver ◽  
Liver Biopsies

Chronic hepatitises of various etiologies are widespread liver diseases in humans. Their final stage, liver cirrhosis (LC), is considered to be one of the main causes of hepatocellular carcinoma (HCC). About 80–90% of all HCC cases develop in LC patients, which suggests that cirrhotic conditions play a crucial role in the process of hepatocarcinogenesis. Carbohydrate metabolism in LC undergoes profound disturbances characterized by altered glycogen metabolism. Unfortunately, data on the glycogen content in LC are few and contradictory. In this study, the material was obtained from liver biopsies of patients with LC of viral and alcohol etiology and from the liver tissue of rats with CCl4-induced LC. The activity of glycogen phosphorylase (GP), glycogen synthase (GS), and glucose-6-phosphatase (G6Pase) was investigated in human and rat liver tissue by biochemical methods. Total glycogen and its labile and stable fractions were measured in isolated individual hepatocytes, using the cytofluorometry technique of PAS reaction in situ. The development of LC in human and rat liver was accompanied by an increase in fibrous tissue (20- and 8.8-fold), an increase in the dry mass of hepatocytes (by 25.6% and 23.7%), and a decrease in the number of hepatocytes (by 50% and 28%), respectively. The rearrangement of the liver parenchyma was combined with changes in glycogen metabolism. The present study showed a significant increase in the glycogen content in the hepatocytes of the human and the rat cirrhotic liver, by 255% and 210%, respectively. An increased glycogen content in cells of the cirrhotic liver can be explained by a decrease in glycogenolysis due to a decreased activity of G6Pase and GP.

scholarly journals Renal Glycogen Content and Hormonal Control of Enzymes Involved in Renal Glycogen Metabolism

1983 ◽  
Vol 17 (9) ◽  
pp. 766-769 ◽  
Author(s):  
Evelyne Delaval ◽  
Evelyne Moreau ◽  
Solomandimbinirina Andriamanantsara ◽  
Jean-Pierre Geloso
Keyword(s):  
Glycogen Content ◽  
Glycogen Metabolism ◽  
Hormonal Control

The role of sympathetic innervation in the developing rat gubernaculum

2007 ◽  
Vol 42 (2) ◽  
pp. 350-354
Author(s):  
Yasunari Sasaki ◽  
John M. Hutson ◽  
Melanie C.C. Clarke
Keyword(s):  
Sympathetic Innervation ◽  
Developing Rat

scholarly journals A dynamic, imperturbable link between midbrain activity and saccade velocity

2020 ◽  
Vol 123 (2) ◽  
pp. 451-453
Author(s):  
Joshua A. Seideman
Keyword(s):  
Eye Movement ◽  
Strong Evidence ◽  
Neural Control ◽  
Oculomotor Control ◽  
Saccadic Eye Movement ◽  
Saccade Velocity ◽  
Midbrain Structure ◽  
Instantaneous Control ◽  
Dynamic Moment

We make a saccadic eye movement once every few hundred milliseconds; however, the neural control of saccade execution is not fully understood. Dynamic, moment-by-moment variations in saccade velocity are typically thought to be controlled by neurons in the lower, but not the upper regions of the brainstem. In a recent report, Smalianchuk et al. (Smalianchuk I, Jagadisan UK, Gandhi NJ. J Neurosci 38: 10156–10167, 2018) provided strong evidence for a role of the superior colliculus, a midbrain structure, in the instantaneous control of saccade velocity, suggesting the revision of long-standing models of oculomotor control.

The role of photoperiod and temperature in the induction and termination of an arrested development in two species of freshwater cyclopia copepods

1971 ◽  
Vol 49 (6) ◽  
pp. 855-862 ◽  
Author(s):  
Nelson H. F. Watson ◽  
B. N. Smallman
Keyword(s):  
Continuous Light ◽  
Temporary Pond ◽  
Environmental Cues ◽  
Complete Darkness ◽  
Arrested Development ◽  
Short Day ◽  
Long Day ◽  
Critical Daylength ◽  
Ecological Implications

Daylength and temperature were shown to be environmental cues which interact to cause an arrest in development at the fourth copepodite instar of two cohabiting, temporary pond species of the genus Diacyclops; D. navus Herrick, and a second species of uncertain specific designation. The first species entered arrest under short-day conditions, the latter under long days. Arrest did not occur in rearings conducted in either continuous light or complete darkness. Cyclopids were sensitive to the photoperiodic stimulus only during the first copepodite instar. Temperature was shown to affect the critical daylength values associated with a transition from a long-day to a short-day response for each species.Similarities with insect diapause and the ecological implications of the response are discussed.

scholarly journals Genome-wide fitness assessment during diurnal growth reveals an expanded role of the cyanobacterial circadian clock protein KaiA

2018 ◽  
Vol 115 (30) ◽  
pp. E7174-E7183 ◽  
Author(s):  
David G. Welkie ◽  
Benjamin E. Rubin ◽  
Yong-Gang Chang ◽  
Spencer Diamond ◽  
Scott A. Rifkin ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Continuous Light ◽  
Axial Rotation ◽  
Time Of Day ◽  
Negative Regulator ◽  
Photosynthetic Organisms ◽  
Environmental Responsiveness ◽  
Environmental Responses ◽  
Clock Protein

The recurrent pattern of light and darkness generated by Earth’s axial rotation has profoundly influenced the evolution of organisms, selecting for both biological mechanisms that respond acutely to environmental changes and circadian clocks that program physiology in anticipation of daily variations. The necessity to integrate environmental responsiveness and circadian programming is exemplified in photosynthetic organisms such as cyanobacteria, which depend on light-driven photochemical processes. The cyanobacterium Synechococcus elongatus PCC 7942 is an excellent model system for dissecting these entwined mechanisms. Its core circadian oscillator, consisting of three proteins, KaiA, KaiB, and KaiC, transmits time-of-day signals to clock-output proteins, which reciprocally regulate global transcription. Research performed under constant light facilitates analysis of intrinsic cycles separately from direct environmental responses but does not provide insight into how these regulatory systems are integrated during light–dark cycles. Thus, we sought to identify genes that are specifically necessary in a day–night environment. We screened a dense bar-coded transposon library in both continuous light and daily cycling conditions and compared the fitness consequences of loss of each nonessential gene in the genome. Although the clock itself is not essential for viability in light–dark cycles, the most detrimental mutations revealed by the screen were those that disrupt KaiA. The screen broadened our understanding of light–dark survival in photosynthetic organisms, identified unforeseen clock–protein interaction dynamics, and reinforced the role of the clock as a negative regulator of a nighttime metabolic program that is essential for S. elongatus to survive in the dark.

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