Cellular energy levels and their effect on male cell abortion in cytoplasmically male sterile lines of Petunia hybrida

1989 ◽  
Vol 2 (3) ◽  
Author(s):  
X.C. Liu ◽  
H.G. Dickinson
Keyword(s):  
Petunia Hybrida ◽  
Energy Levels ◽  
Male Sterile ◽  
Male Cell ◽  
Cellular Energy

scholarly journals Activation of AMPK under Hypoxia: Many Roads Leading to Rome

2020 ◽  
Vol 21 (7) ◽  
pp. 2428 ◽  
Author(s):  
Franziska Dengler
Keyword(s):  
Current Knowledge ◽  
Protective Action ◽  
Energy Levels ◽  
Hypoxia Inducible Factor ◽  
Protective Effects ◽  
Ampk Activation ◽  
Cellular Energy ◽  
Energy Sensor ◽  
Atp Supply ◽  
Amp Activated Protein Kinase

AMP-activated protein kinase (AMPK) is known as a pivotal cellular energy sensor, mediating the adaptation to low energy levels by deactivating anabolic processes and activating catabolic processes in order to restore the cellular ATP supply when the cellular AMP/ATP ratio is increased. Besides this well-known role, it has also been shown to exert protective effects under hypoxia. While an insufficient supply with oxygen might easily deplete cellular energy levels, i.e., ATP concentration, manifold other mechanisms have been suggested and are heavily disputed regarding the activation of AMPK under hypoxia independently from cellular AMP concentrations. However, an activation of AMPK preceding energy depletion could induce a timely adaptation reaction preventing more serious damage. A connection between AMPK and the master regulator of hypoxic adaptation via gene transcription, hypoxia-inducible factor (HIF), has also been taken into account, orchestrating their concerted protective action. This review will summarize the current knowledge on mechanisms of AMPK activation under hypoxia and its interrelationship with HIF.

scholarly journals The Balance between Life and Death of Cells: Roles of Metallothioneins

2006 ◽  
Vol 1 ◽  
pp. 117727190600100 ◽  
Author(s):  
Allan Evald Nielsen ◽  
Adam Bohr ◽  
Milena Penkowa
Keyword(s):  
Metal Ion ◽  
Molecular Mechanisms ◽  
Energy Levels ◽  
Ion Homeostasis ◽  
Cellular Survival ◽  
Life And Death ◽  
Cellular Energy ◽  
Metal Ion Homeostasis ◽  
Pathological Conditions ◽  
Cysteine Rich Protein

Metallothionein (MT) is a highly conserved, low-molecular-weight, cysteine-rich protein that occurs in 4 isoforms (MT-I to MT-IV), of which MT-I+II are the major and best characterized proteins. This review will focus on mammalian MT-I+II and their functional impact upon cellular survival and death, as seen in two rather contrasting pathological conditions: Neurodegeneration and neoplasms. MT-I+II have analogous functions including: 1) Antioxidant scavenging of reactive oxygen species (ROS); 2) Cytoprotection against degeneration and apoptosis; 3) Stimulation of cell growth and repair including angiogenesis/revascularization, activation of stem/progenitor cells, and neuroregeneration. Thereby, MT-I+II mediate neuroprotection, CNS restoration and clinical recovery during neurodegenerative disorders. Due to the promotion of cell survival, increased MT-I+II levels have been associated with poor tumor prognosis, although the data are less clear and direct causative roles of MT-I+II in oncogenesis remain to be identified. The MT-I+II molecular mechanisms of actions are not fully elucidated. However, their role in metal ion homeostasis might be fundamental in controlling Zn-dependent transcription factors, protein synthesis, cellular energy levels/metabolism and cell redox state. Here, the neuroprotective and regenerative functions of MT-I+II are reviewed, and the presumed link to oncogenesis is critically perused.

scholarly journals AMPK: a cellular energy sensor primarily regulated by AMP

2014 ◽  
Vol 42 (1) ◽  
pp. 71-75 ◽  
Author(s):  
Graeme J. Gowans ◽  
D. Grahame Hardie
Keyword(s):  
Energy Levels ◽  
Allosteric Activation ◽  
Intact Cells ◽  
Cellular Energy ◽  
Physiological Signal ◽  
The Third ◽  
Energy Sensor ◽  
Primary Signal ◽  
Significant Mechanism ◽  
Amp Activated Protein Kinase

AMPK (AMP-activated protein kinase) is a cellular energy sensor that monitors the ratio of AMP/ATP, and possibly also ADP/ATP, inside cells. Once activated by falling cellular energy levels, it acts to restore energy homoeostasis by switching on catabolic pathways that generate ATP, while switching off anabolic pathways and other processes consuming ATP. AMPK is switched on by increases in AMP via three mechanisms, all of which are antagonized by ATP: (i) promotion of phosphorylation of Thr172 by upstream activating kinases; (ii) inhibition of dephosphorylation of Thr172 by phosphatases; and (iii) allosteric activation of the phosphorylated kinase. Recently, it has been proposed that the first two mechanisms are also triggered by ADP, which might be the physiological signal rather than AMP, and that the third mechanism may not be physiologically significant. We have re-evaluated these questions, and found that only mechanism (ii) is mimicked by ADP, and that ADP is also less potent than AMP, which we still believe to be the primary signal. We have also provided evidence that mechanism (iii), i.e. allosteric activation by AMP, is a quantitatively significant mechanism in intact cells.

scholarly journals Ultraweak photon emission in strawberry fruit during ripening and aging is related to energy level

2017 ◽  
Vol 12 (1) ◽  
pp. 393-398 ◽  
Author(s):  
Jinli Guo ◽  
Guanyu Zhu ◽  
Lianguo Li ◽  
Huan Liu ◽  
Shuang Liang
Keyword(s):  
Energy Source ◽  
Energy Level ◽  
Energy Levels ◽  
Energy Charge ◽  
Photon Emission ◽  
Adenosine Monophosphate ◽  
Adenosine Diphosphate ◽  
Strawberry Fruit ◽  
Cellular Energy ◽  
Living Organisms

AbstractBackgroundUltra-weak photon emission (UPE), or biophoton emission, is a phenomenon observed in various living organisms, including plants. In this study, we analyzed the UPE from ripening strawberry fruits, to elucidate its source and association with cellular energy.MethodsFreshly harvested and stored strawberry fruits were measured for levels of UPE and energy molecules adenosine triphosphate (ATP), adenosine monophosphate (AMP) and adenosine diphosphate (ADP). The associations between them were calculated.ResultsIn ripening fruit, a decrease in UPE positively correlated with declining levels of ATP, AMP, and energy charge. In harvested fruits, levels of UPE, ATP, and energy charge declined, but ADP and AMP increased.ConclusionChanges in UPE levels synchronized with changes in ATP and energy charge, which reflect cellular energy levels. Thus, cellular energy may be related to UPE, and may be an energy source for UPE.

scholarly journals PAS Domains: Internal Sensors of Oxygen, Redox Potential, and Light

1999 ◽  
Vol 63 (2) ◽  
pp. 479-506 ◽  
Author(s):  
Barry L. Taylor ◽  
Igor B. Zhulin
Keyword(s):  
Redox Potential ◽  
Early Warning System ◽  
Energy Levels ◽  
Warning System ◽  
Living Cells ◽  
Internal Environment ◽  
Hypoxia Inducible Factors ◽  
Cellular Energy ◽  
Fundamental Properties ◽  
Signaling Domains

SUMMARY PAS domains are newly recognized signaling domains that are widely distributed in proteins from members of the Archaea and Bacteria and from fungi, plants, insects, and vertebrates. They function as input modules in proteins that sense oxygen, redox potential, light, and some other stimuli. Specificity in sensing arises, in part, from different cofactors that may be associated with the PAS fold. Transduction of redox signals may be a common mechanistic theme in many different PAS domains. PAS proteins are always located intracellularly but may monitor the external as well as the internal environment. One way in which prokaryotic PAS proteins sense the environment is by detecting changes in the electron transport system. This serves as an early warning system for any reduction in cellular energy levels. Human PAS proteins include hypoxia-inducible factors and voltage-sensitive ion channels; other PAS proteins are integral components of circadian clocks. Although PAS domains were only recently identified, the signaling functions with which they are associated have long been recognized as fundamental properties of living cells.

scholarly journals Deficiency of LKB1 in heart prevents ischemia-mediated activation of AMPKα2 but not AMPKα1

2006 ◽  
Vol 290 (5) ◽  
pp. E780-E788 ◽  
Author(s):  
Kei Sakamoto ◽  
Elham Zarrinpashneh ◽  
Grant R. Budas ◽  
Anne-Catherine Pouleur ◽  
Anindya Dutta ◽  
...  
Keyword(s):  
Cardiac Muscle ◽  
Crucial Role ◽  
Morphological Analysis ◽  
Energy Levels ◽  
Acetyl Coa Carboxylase ◽  
Acetyl Coa ◽  
Cellular Energy ◽  
Basal Activity ◽  
Upstream Kinase ◽  
Amp Activated Protein Kinase

Recent studies indicate that the LKB1 is a key regulator of the AMP-activated protein kinase (AMPK), which plays a crucial role in protecting cardiac muscle from damage during ischemia. We have employed mice that lack LKB1 in cardiac and skeletal muscle and studied how this affected the activity of cardiac AMPKα1/α2 under normoxic, ischemic, and anoxic conditions. In the heart lacking cardiac muscle LKB1, the basal activity of AMPKα2 was vastly reduced and not increased by ischemia or anoxia. Phosphorylation of AMPKα2 at the site of LKB1 phosphorylation (Thr172) or phosphorylation of acetyl-CoA carboxylase-2, a downstream substrate of AMPK, was ablated in ischemic heart lacking cardiac LKB1. Ischemia was found to increase the ADP-to-ATP (ADP/ATP) and AMP-to-ATP ratios (AMP/ATP) to a greater extent in LKB1-deficient cardiac muscle than in LKB1-expressing muscle. In contrast to AMPKα2, significant basal activity of AMPKα1 was observed in the lysates from the hearts lacking cardiac muscle LKB1, as well as in cardiomyocytes that had been isolated from these hearts. In the heart lacking cardiac LKB1, ischemia or anoxia induced a marked activation and phosphorylation of AMPKα1, to a level that was only moderately lower than observed in LKB1-expressing heart. Echocardiographic and morphological analysis of the cardiac LKB1-deficient hearts indicated that these hearts were not overtly dysfunctional, despite possessing a reduced weight and enlarged atria. These findings indicate that LKB1 plays a crucial role in regulating AMPKα2 activation and acetyl-CoA carboxylase-2 phosphorylation and also regulating cellular energy levels in response to ischemia. They also provide genetic evidence that an alternative upstream kinase can activate AMPKα1 in cardiac muscle.

scholarly journals c-Myc and AMPK Control Cellular Energy Levels by Cooperatively Regulating Mitochondrial Structure and Function

PLoS ONE ◽  
2015 ◽  
Vol 10 (7) ◽  
pp. e0134049 ◽  
Author(s):  
Lia R. Edmunds ◽  
Lokendra Sharma ◽  
Huabo Wang ◽  
Audry Kang ◽  
Sonia d’Souza ◽  
...  
Keyword(s):  
Energy Levels ◽  
Structure And Function ◽  
Cellular Energy ◽  
Mitochondrial Structure ◽  
And Function
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