scholarly journals Involvement of Membrane Fluidity in Endogenous Protective Processes Running on Subcellular Membrane Systems of the Rat Heart

2012 ◽  
pp. S11-S21 ◽  
Author(s):  
A. ZIEGELHÖFFER ◽  
I. WACZULÍKOVÁ ◽  
M. FERKO ◽  
L. ŠIKUROVÁ ◽  
J. MUJKOŠOVÁ ◽  
...  
Keyword(s):  
Membrane Fluidity ◽  
Structural Organization ◽  
Membrane Systems ◽  
Cardiac Sarcolemma ◽  
Subcellular Membrane ◽  
Enzyme Systems ◽  
Endogenous Protection ◽  
Protective Processes ◽  
Membrane Bound

Membrane fluidity is a widely recognized biophysical variable that provides information about structural organization of the subcellular membranes exhibiting physical characteristics of liquid crystals. The term “fluidity” reflects in this case the tightness in packing of acyl parts of the membrane phospholipid molecules, a feature that may influence considerably the molecular mobility and via that also the sensitivity and reactivity of membrane-bound transporters, receptors and enzyme systems. Data presented in this review are aimed to demonstrate the substantial role of changes in membrane fluidity occurring in the processes associated with endogenous protection observed in cardiac sarcolemma and mitochondria in diverse pathologies, particularly in diabetes and hypertension.

Role of phosphatidylethanol in membranes. Effects on membrane fluidity, tolerance to ethanol, and activity of membrane-bound enzymes

Biochemistry ◽  
1991 ◽  
Vol 30 (9) ◽  
pp. 2477-2482 ◽  
Author(s):  
Fausta Omodeo-Sale ◽  
Clara Lindi ◽  
Paola Palestini ◽  
Massimo Masserini
Keyword(s):  
Membrane Fluidity ◽  
Membrane Bound ◽  
Membrane Bound Enzymes ◽  
Tolerance To Ethanol

Role of lindane in membranes. Effects on membrane fluidity and activity of membrane-bound proteins

1994 ◽  
Vol 14 (3) ◽  
pp. 131-138 ◽  
Author(s):  
P. López-Aparicio ◽  
M. N. Recio ◽  
J. C. Prieto ◽  
M. A. Pérez-Albarsanz
Keyword(s):  
Membrane Fluidity ◽  
Adrenergic Receptor ◽  
Plasma Membranes ◽  
Opposite Effect ◽  
Glucose Transporter ◽  
Regulatory Mechanism ◽  
Cyclic Amp Accumulation ◽  
Membrane Bound ◽  
The Difference

The influence of lindane (gamma-hexachlorocyclohexane) on fluidity of plasma membranes from rat renal cortical tubules has been investigated. Preincubation with lindane increased membrane fluidity. This effect was accompanied by (i) a decrease in the transport of glucose with regard to the controls and (ii) an inhibition of the β-adrenergic stimulatory activity upon cyclic AMP accumulation. However, a significant decrease of the membrane fluidity was found when rats were injected with lindane for 12 days. The injection of lindane exerted the opposite effect on the membrane proteins, the glucose transporter and the β-adrenergic receptor, enhancing the glucose uptake and increasing the isoproterenol-stimulated cycle AMP accumulation. A possible explanation of the difference could involve a resistance to membrane disordering by lindane through a regulatory mechanism that would balance the activity of many lindane-sensitive proteins in insecticide-injected rats.

Quantitative Conditions and Convergent Operations That Are Compatible With the Universe as a Persistent Generator of Successive Simulations

2016 ◽  
Vol 12 (1) ◽  
pp. 4178-4187
Author(s):  
Michael A Persinger ◽  
Stanley A Koren
Keyword(s):  
Structural Organization ◽  
Total Duration ◽  
Human Cognition ◽  
Intrinsic Properties ◽  
Basic Assumptions ◽  
Electron Orbit ◽  
Quantitative Analyses ◽  
Massive Information ◽  
The Universe

                The capacity for computer-like simulations to be generated by massive information processing from electron-spin potentials supports Bostrom’s hypothesis that matter and human cognition might reflect simulations. Quantitative analyses of the basic assumptions indicate the universe may display properties of a simulation where photons behave as pixels and gravitons control the structural organization. The Lorentz solution for the square of the light and entanglement velocities converges with the duration of a single electron orbit that ultimately defines properties of matter. The approximately one trillion potential states within the same space with respect to the final epoch of the universe indicate that a different simulation, each with intrinsic properties, has been and will be generated as a type of tractrix defined by ±2 to 3 days (total duration 5 to 6 days). It may define the causal limits within a simulation. Because of the intrinsic role of photons as the pixel unit, phenomena within which flux densities are enhanced, such as human cognition (particularly dreaming) and the cerebral regions associated with those functions, create the conditions for entanglement or excess correlations between contiguous simulations. The consistent quantitative convergence of operations indicates potential validity for this approach. The emergent solutions offer alternative explanations for the limits of predictions for multivariate phenomena that could be coupled to more distal simulations.

scholarly journals Genetic and Phenotypic Analyses of therdx Locus of Rhodobacter sphaeroides2.4.1

2000 ◽  
Vol 182 (12) ◽  
pp. 3475-3481 ◽  
Author(s):  
Jung Hyeob Roh ◽  
Samuel Kaplan
Keyword(s):  
Gene Expression ◽  
Rhodobacter Sphaeroides ◽  
Redox Protein ◽  
Deletion Mutations ◽  
Metal Transporter ◽  
New Class ◽  
Mutant Strains ◽  
Membrane Bound ◽  
Photosynthesis Gene

ABSTRACT Previously, we reported that rdxB, encoding a likely membrane-bound two [4Fe-4S]-containing center, is involved in the aerobic regulation of photosystem gene expression in Rhodobacter sphaeroides 2.4.1. To further investigate the role ofrdxB as well as other genes of the rdxBHISoperon on photosystem gene expression, we constructed a series of nonpolar, in-frame deletion mutations in each of the rdxgenes. Using both puc and puf operonlacZ fusions to monitor photosystem gene expression, under aerobic conditions, in each of the mutant strains revealed significant increased photosynthesis gene expression. In the case of mutations in either rdxH, rdxI, or rdxS, the aerobic induction of photosystem gene expression is believed to be indirect by virtue of a posttranscriptional effect oncbb 3 cytochrome oxidase structure and integrity. For RdxB, we suggest that this redox protein has a more direct effect on photosystem gene expression by virtue of its interaction with the cbb 3 oxidase. An associated phenotype, involving the enhanced conversion of the carotenoid spheroidene to spheroidenone, is also observed in the RdxB, -H, -I, and -S mutant strains. This phenotype is also suggested to be the result of the role of the rdxBHIS locus incbb 3 oxidase activity and/or structure. RdxI is suggested to be a new class of metal transporter of the CPx-type ATPases.

scholarly journals The role of modulation of antioxidant enzyme systems in the treatment of neurodegenerative diseases

2016 ◽  
Vol 31 (sup3) ◽  
pp. 194-204 ◽  
Author(s):  
Sybil Obuobi ◽  
Sanzhar Karatayev ◽  
Christina Li Lin Chai ◽  
Pui Lai Rachel Ee ◽  
Peter Mátyus
Keyword(s):  
Neurodegenerative Diseases ◽  
Antioxidant Enzyme ◽  
Enzyme Systems

scholarly journals Advances in understanding the role of cardiac glycosides in control of sodium transport in renal tubules

2014 ◽  
Vol 222 (1) ◽  
pp. R11-R24 ◽  
Author(s):  
Syed Jalal Khundmiri
Keyword(s):  
Heart Failure ◽  
Intracellular Signaling ◽  
Cardiac Contractility ◽  
Myocardial Cell ◽  
Renal Tubules ◽  
Intracellular Signaling Pathway ◽  
Body Sodium ◽  
Membrane Bound ◽  
Total Body

Cardiotonic steroids have been used for the past 200 years in the treatment of congestive heart failure. As specific inhibitors of membrane-bound Na+/K+ATPase, they enhance cardiac contractility through increasing myocardial cell calcium concentration in response to the resulting increase in intracellular Na concentration. The half-minimal concentrations of cardiotonic steroids required to inhibit Na+/K+ATPase range from nanomolar to micromolar concentrations. In contrast, the circulating levels of cardiotonic steroids under physiological conditions are in the low picomolar concentration range in healthy subjects, increasing to high picomolar levels under pathophysiological conditions including chronic kidney disease and heart failure. Little is known about the physiological function of low picomolar concentrations of cardiotonic steroids. Recent studies have indicated that physiological concentrations of cardiotonic steroids acutely stimulate the activity of Na+/K+ATPase and activate an intracellular signaling pathway that regulates a variety of intracellular functions including cell growth and hypertrophy. The effects of circulating cardiotonic steroids on renal salt handling and total body sodium homeostasis are unknown. This review will focus on the role of low picomolar concentrations of cardiotonic steroids in renal Na+/K+ATPase activity, cell signaling, and blood pressure regulation.

Dietary Selenium or Zinc Supplementation Restores Brain Lipid Composition and Membrane Fluidity in Protein-Undernourished Rats

2016 ◽  
Vol 38 (6) ◽  
pp. 397-406
Author(s):  
Olusegun L. Adebayo ◽  
Bamidele A. Salau ◽  
Rajat Sandhir ◽  
Gbenga A. Adenuga
Keyword(s):  
Membrane Fluidity ◽  
Lipid Composition ◽  
Zinc Supplementation ◽  
Protective Role ◽  
Membrane Lipid ◽  
Limited Information ◽  
Total Lipids ◽  
Major Focus ◽  
Membrane Lipid Composition

Studies have shown that protein undernutrition (PU) modifies the membrane lipid composition in the intestine and liver, as well as in plasma and other areas. However, there is limited information on the effect of PU on synaptosomal membrane lipid composition and fluidity and the protective role of selenium (Se) and zinc (Zn), which is a major focus of the present study. For 10 weeks, rats were fed diets containing 16% casein, which constituted the adequate protein diet, or 5% casein, representing the PU diet. The animals were supplemented with Se and Zn at a concentration of 0.15 and 227 mg L-1, respectively, in drinking water for 3 weeks. The results showed a significant increase in total lipids, glycolipids, triglycerides, cholesterol, and the cholesterol/phospholipid (Chol/PL) ratio, and a significant reduction in phospholipids and membrane fluidity. Se and Zn supplementation to PU rats, however, significantly lowered total lipids, glycolipids, triglycerides, cholesterol, and the Chol/PL ratio, while phospholipids and membrane fluidity were significantly restored. It is concluded that a perturbed lipid composition induced by PU affects the membrane structure and fluidity, which in turn influences membrane functions. The study suggests that Se and Zn supplementation might be beneficial in restoring the lipid dyshomeostasis associated with PU.

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