Regulatory mechanisms of hepatic phosphorylase in fetal and neonatal livers of rats.

1977 ◽  
Vol 232 (4) ◽  
pp. E370
Author(s):  
R Biondi ◽  
M P Viola-Magni
Keyword(s):  
Actinomycin D ◽  
De Novo ◽  
Fetal Liver ◽  
Glycogen Metabolism ◽  
Regulatory Mechanisms ◽  
De Novo Synthesis ◽  
Neonatal Liver ◽  
Enzymatic Changes ◽  
Rat Livers

Active phosphorylase was determined in rat livers during the end of the fetal period and the first days of life. This enzyme increases between the 16th day of gestation and birth. After birth, another increase in observed that takes place with 6 h. In the neonatal liver, the rapid increase in active phosphorylase, is inhibited by high levels of blood glucose, but is unaffected by actinomycin D. In fetal liver glucagon administration is followed after 5 h by an increase in total phosphorylase with only a small increase in active phosphorylase; this effect is blocked by actinomycin D. The fetal changes are interpreted as de novo synthesis, whereas the neonatal increase is due to an activation of inactive phosphorylase. Both enzymatic changes appear to be regulated by glycogen. The role of phosphorylase in the regulation of glycogen metabolism in neonatal liver is discussed.

scholarly journals Evidence for the De Novo Synthesis of Erythropoietin in Hypoxic Rats

Blood ◽  
1972 ◽  
Vol 40 (5) ◽  
pp. 662-670 ◽  
Author(s):  
J. C. Schooley ◽  
L. J. Mahlmann
Keyword(s):  
Rna Synthesis ◽  
Actinomycin D ◽  
De Novo ◽  
Protein S ◽  
Male Rats ◽  
Hypoxic Exposure ◽  
De Novo Synthesis ◽  
Serum Erythropoietin

Abstract Significant increases in the serum erythropoietin of male rats occur after the end of a brief hypoxic exposure. These increases in the hormone are almost completely abolished when the kidneys are removed after the hypoxic exposure. Injection of puromycin or cycloheximide after the hypoxic exposure significantly decreases the subsequent increases in serum erythropoietin titers, whereas injections of actinomycin D at this time have no significant effect on erythropoietin levels. Injections of actinomycin D before the hypoxic exposure prevent the increase in serum erythropoietin that normally occurs. These findings suggest that a brief period of hypoxia initiates a DNA-dependent RNA synthesis that regulates the de novo ribosomal synthesis of protein(s) involved in the biogenesis of erythropoietin and that the kidney is essential for these reactions to occur.

scholarly journals The Role of Mitochondrial Dysfunction in the Progression of Alzheimer’s Disease

2019 ◽  
Vol 25 (40) ◽  
pp. 5578-5587 ◽  
Author(s):  
Claus Desler ◽  
Meryl S. Lillenes ◽  
Tone Tønjum ◽  
Lene Juel Rasmussen
Keyword(s):  
Alzheimer’S Disease ◽  
Reactive Oxygen Species ◽  
Alzheimer's Disease ◽  
Mitochondrial Dysfunction ◽  
De Novo ◽  
Oxygen Species ◽  
De Novo Synthesis ◽  
Atp Production ◽  
Essential Phospholipids

The current molecular understanding of Alzheimer’s disease (AD) has still not resulted in successful interventions. Mitochondrial dysfunction of the AD brain is currently emerging as a hallmark of this disease. One mitochondrial function often affected in AD is oxidative phosphorylation responsible for ATP production, but also for production of reactive oxygen species (ROS) and for the de novo synthesis of pyrimidines. This paper reviews the role of mitochondrial produced ROS and pyrimidines in the aetiology of AD and their proposed role in oxidative degeneration of macromolecules, synthesis of essential phospholipids and maintenance of mitochondrial viability in the AD brain.

The role of particulate carbon in the de-novo synthesis of polychlorinated dibenzodioxins and-furans in fly-ash

Chemosphere ◽  
1990 ◽  
Vol 20 (10-12) ◽  
pp. 1953-1958 ◽  
Author(s):  
L. Stieglitz ◽  
G. Zwick ◽  
J. Beck ◽  
H. Bautz ◽  
W. Roth
Keyword(s):  
Fly Ash ◽  
De Novo ◽  
De Novo Synthesis ◽  
Particulate Carbon ◽  
Polychlorinated Dibenzodioxins

scholarly journals NAD+-Dependent Deacetylase Hst1p Controls Biosynthesis and Cellular NAD+ Levels in Saccharomyces cerevisiae

2003 ◽  
Vol 23 (19) ◽  
pp. 7044-7054 ◽  
Author(s):  
Antonio Bedalov ◽  
Maki Hirao ◽  
Jeffrey Posakony ◽  
Melisa Nelson ◽  
Julian A. Simon
Keyword(s):  
De Novo ◽  
Critical Role ◽  
Salvage Pathway ◽  
De Novo Synthesis ◽  
Array Analysis ◽  
Binding Partner ◽  
Dependent Protein ◽  
New Protein

ABSTRACT Nicotine adenine dinucleotide (NAD+) performs key roles in electron transport reactions, as a substrate for poly(ADP-ribose) polymerase and NAD+-dependent protein deacetylases. In the latter two processes, NAD+ is consumed and converted to ADP-ribose and nicotinamide. NAD+ levels can be maintained by regeneration of NAD+ from nicotinamide via a salvage pathway or by de novo synthesis of NAD+ from tryptophan. Both pathways are conserved from yeast to humans. We describe a critical role of the NAD+-dependent deacetylase Hst1p as a sensor of NAD+ levels and regulator of NAD+ biosynthesis. Using transcript arrays, we show that low NAD+ states specifically induce the de novo NAD+ biosynthesis genes while the genes in the salvage pathway remain unaffected. The NAD+-dependent deacetylase activity of Hst1p represses de novo NAD+ biosynthesis genes in the absence of new protein synthesis, suggesting a direct effect. The known Hst1p binding partner, Sum1p, is present at promoters of highly inducible NAD+ biosynthesis genes. The removal of HST1-mediated repression of the NAD+ de novo biosynthesis pathway leads to increased cellular NAD+ levels. Transcript array analysis shows that reduction in cellular NAD+ levels preferentially affects Hst1p-regulated genes in comparison to genes regulated with other NAD+-dependent deacetylases (Sir2p, Hst2p, Hst3p, and Hst4p). In vitro experiments demonstrate that Hst1p has relatively low affinity toward NAD+ in comparison to other NAD+-dependent enzymes. These findings suggest that Hst1p serves as a cellular NAD+ sensor that monitors and regulates cellular NAD+ levels.

scholarly journals SCAP/SREBP pathway is required for the full steroidogenic response to cyclic AMP

2016 ◽  
Vol 113 (38) ◽  
pp. E5685-E5693 ◽  
Author(s):  
Masami Shimizu-Albergine ◽  
Brian Van Yserloo ◽  
Martin G. Golkowski ◽  
Shao-En Ong ◽  
Joseph A. Beavo ◽  
...  
Keyword(s):  
Cyclic Amp ◽  
Leydig Cells ◽  
De Novo ◽  
Regulatory Element ◽  
De Novo Synthesis ◽  
Intracellular Lipid ◽  
Element Binding Protein ◽  
Short Palindromic Repeat ◽  
Sterol Regulatory Element

Luteinizing hormone (LH) stimulates steroidogenesis largely through a surge in cyclic AMP (cAMP). Steroidogenic rates are also critically dependent on the availability of cholesterol at mitochondrial sites of synthesis. This cholesterol is provided by cellular uptake of lipoproteins, mobilization of intracellular lipid, and de novo synthesis. Whether and how these pathways are coordinated by cAMP are poorly understood. Recent phosphoproteomic analyses of cAMP-dependent phosphorylation sites in MA10 Leydig cells suggested that cAMP regulates multiple steps in these processes, including activation of the SCAP/SREBP pathway. SCAP [sterol-regulatory element-binding protein (SREBP) cleavage-activating protein] acts as a cholesterol sensor responsible for regulating intracellular cholesterol balance. Its role in cAMP-mediated control of steroidogenesis has not been explored. We used two CRISPR (clustered regularly interspaced short palindromic repeat)-Cas9 (CRISPR associated protein 9) knockout approaches to test the role of SCAP in steroidogenesis. Our results demonstrate that SCAP is required for progesterone production induced by concurrent inhibition of the cAMP phosphodiesterases PDE4 and PDE8. These inhibitors increased SCAP phosphorylation, SREBP2 activation, and subsequent expression of cholesterol biosynthetic genes, whereas SCAP deficiency largely prevented these effects. Reexpression of SCAP in SCAP-deficient cells restored SREBP2 protein expression and partially restored steroidogenic responses, confirming the requirement of SCAP–SREBP2 in steroidogenesis. Inhibitors of 3-hydroxy-3-methylglutaryl-Coenzyme A reductase and isoprenylation attenuated, whereas exogenously provided cholesterol augmented, PDE inhibitor-induced steroidogenesis, suggesting that the cholesterol substrate needed for steroidogenesis is provided by both de novo synthesis and isoprenylation-dependent mechanisms. Overall, these results demonstrate a novel role for LH/cAMP in SCAP/SREBP activation and subsequent regulation of steroidogenesis.

scholarly journals EFFECTS OF CYTOSINE ARABINOSIDE ON DIFFERENTIAL GENE EXPRESSION IN EMBRYONIC NEURAL RETINA

1974 ◽  
Vol 61 (3) ◽  
pp. 688-700 ◽  
Author(s):  
R. E. Jones ◽  
A. A. Moscona
Keyword(s):  
Cytosine Arabinoside ◽  
Rna Synthesis ◽  
Actinomycin D ◽  
De Novo ◽  
Neural Retina ◽  
Regulatory Genes ◽  
De Novo Synthesis ◽  
Macromolecular Synthesis ◽  
Differential Gene ◽  
Inhibition Of Dna Synthesis

The analogue of cytidine, cytosine arabinoside (Ara-C), elicited a significant increase in the level of glutamine synthetase (GS) in embryonic chick neural retina in the absence of the steroid inducer of the enzyme. The increase was due to de novo synthesis of GS and was mediated by RNA which accumulated in the presence of the effective concentration of Ara-C. Accumulation of GS did not result from the inhibition of DNA synthesis for which Ara-C is best known. This new effect of Ara-C involves differential suppression of macromolecular synthesis in this system: the concentration of Ara-C which caused maximum GS accumulation suppressed overall protein and RNA syntheses 65–75% without inhibiting the transcription and translation of templates essential for GS synthesis. Withdrawal of Ara-C resulted in restoration of RNA synthesis and cessation of GS accumulation, even though preformed templates for the enzyme were present; however, if all RNA synthesis was arrested with actinomycin D at the time of Ara-C withdrawal, GS continued to accumulate. The results are consistent with the hypothesis that Ara-C differentially affects the activity of structural and regulatory genes involved in the regulation of GS levels in the retina: Ara-C allows transcription of the enzyme-specific templates, but reversibly inhibits the expression of regulatory genes which limit the accumulation of GS.

Characterization of the AMP-binding protein gene family in Arabidopsis thaliana: will the real acyl-CoA synthetases please stand up?

2000 ◽  
Vol 28 (6) ◽  
pp. 955-957 ◽  
Author(s):  
J. Shockey ◽  
J. Schnurr ◽  
J. Browse
Keyword(s):  
Protein Gene ◽  
De Novo ◽  
Functional Characterization ◽  
De Novo Synthesis ◽  
Triacylglycerol Composition ◽  
Sequence Comparisons ◽  
Triacylglycerol Metabolism ◽  
Binding Protein Gene

One of the most prominent and important topics in modern agricultural biotechnology is the manipulation of oilseed triacylglycerol composition. Towards this goal, we have sought to identify and characterize acyl-CoA synthetases (ACSs), which play an important role in both de novo synthesis and modification of existing lipids. We have identified and cloned 20 different genes that bear strong sequence homology to known ACSs from other organisms. Through sequence comparisons and functional characterization, we have identified several members of this group that encode ACSs, while the other genes fall into the broader category of genes for AMP-binding proteins (AMPBPs). Distinguishing ACSs from AMPBPs will simplify our efforts to understand the role of ACS in triacylglycerol metabolism.

scholarly journals The role of bromine in the de novo synthesis in a model fly ash system

Chemosphere ◽  
1994 ◽  
Vol 28 (7) ◽  
pp. 1299-1309 ◽  
Author(s):  
R. Luijk ◽  
C. Dorland ◽  
P. Smit ◽  
J. Jansen ◽  
H.A.J. Govers
Keyword(s):  
Fly Ash ◽  
De Novo ◽  
De Novo Synthesis ◽  
Model Fly Ash
Sign in / Sign up

Export Citation Format

Share Document