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  • 1
    Electronic Resource
    Electronic Resource
    Power transmission along biological membranes (1990)
    Springer
    The journal of membrane biology 114 (1990), S. 97-112 
    Details
    ISSN: 1432-1424
    Keywords: coupling membranes ; lateral power transmission ; giant mitochondria ; mitochondrial reticulum ; cyanobacterial membranes ; intracellular electric cable
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Hypothesis on long-distance power transmission along extended energy-transducing membranes (Skulachev, 1969, 1971, 1980), has been experimentally proven in four different systems, namely, (i) trichomes of filamentous cyanobacteriumPhormidium uncinatum; (ii) filamentous mitochondria and mitochondrial network in fibroblasts; (iii) clusters of roundish heart muscle mitochondria interconnected with mitochondrial junctions; (iv) mixed animal cell cultures interconnected with gap junctions. In all cases, energy was shown to be transmitted in the form of a transmembrane electric potential difference. The transmission occurred for distances as long as several tens of micrometers. Since the (a) $$\Delta \bar \mu $$ H-bearing cytoplasmic membrane of cyanobacteria and the inner mitochondrial membrane and (b) $$\Delta \bar \mu $$ Na-bearing outer animal cell membrane were found to be competent in such an effect, one may assume that the power transmission is a fundamental function of extended membrane systems. This mechanism can be used at the intracellular level (cytoplasmic and outer cell membranes). Studies on the possible involvement of membranes in lateral transport of oxygen, ions, fatty acids and membrane proteins seem to hold good promise.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01869092
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  • 2
    Electronic Resource
    Electronic Resource
    Bacteriorhodopsin-mediated photoelectric responses in lipid/water systems (1982)
    Springer
    The journal of membrane biology 65 (1982), S. 1-12 
    Details
    ISSN: 1432-1424
    Keywords: bacteriorhodopsin ; proton pump ; retinal ; model lipid membrane ; lipid/water interface ; photoeffects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Summary Bacteriorhodopsin-mediated photopotential generation has been studied in two kinds of lipid/water systems: (1) decane solution of asolectin was used as the lipid phase; (2) a mixture of bacteriorhodopsin sheets and hexane solution of phosphatidyl choline was applied onto a water surface to form a monolayer, and then the monolayer was covered with a 0.3-mm decane layer. In both cases, illumination was found to induce formation of an electric potential difference, with the bulk water phase being found negative when measured with a vibrating electrode. In the latter, but not in the former, system small amounts of a protonophorous uncoupler were found to stimulate the photoresponse. Large amounts of the uncoupler proved depressing in both systems. Phenyldicarbaundecaborane anion (PCB−) was shown to substitute for the uncoupler, being much more potent both as an activator and as an inhibitor of the photoresponse. In both studied systems, gramicidin A inhibits the photoresponse, the effect being greatly potentiated by K+, Na+ or H+ ions. In the system “decane solution of asolectin/water,” an Ag/AgCl electrode immersed into the lipid phase can be used instead of a vibrating electrode. All the measured features of the photoelectric responses observed with any of these electrodes were found to be quite similar to those inherent in a phospholipid-impregnated collodion film adsorbing bacteriorhodopsin sheets on one of its surfaces. A scheme is discussed built on the assumption that photopotentials in all the studied systems are due to an uphill light-dependent transport of H+ ions from the bulk water phase to a water cavity localized between a bacteriorhodopsin sheet and the surface of the bulk lipid phase. Thus, the above lipid/water systems containing bacteriorhodopsin are composed of four, rather than two, phases, as was supposed previously. Bacteriorhodopsin-mediated photopotential generation has been studied also in the decane/water system without phospholipids. This system with bacteriorhodopsin sheets added to the water phase demonstrates a light-dependent photoelectric response reaching 1.5 V, which can be measured only by a vibrating electrode. The photoresponse starts after a lag period of several seconds. Switching off the light results in the reversal of the light-induced electric potential change. The off-effect also has a lag period. The action spectrum of the photoresponse shows at least two maxima: a smaller at 560 nm and a larger at 〈420 nm. Free retinal can substitute for bacteriorhodopsin in the studied system. All the above effects disappear if, instead of air, argon is used. In the system “decane solution of asolectin/water,” a slow photoelectric response of this type can be demonstrated at neutral pH in the presence of gramicidin and at pH 4 without gramicidin. A suggestion is put forward that the slow photoelectric response is due to an interface Volta-potential change induced by a product of photooxidation of bacteriorhodopsin and/or free retinal released from bacteriorhodopsin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01870463
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  • 3
    Electronic Resource
    Electronic Resource
    Chemiosmotic concept of the membrane bioenergetics: What is already clear and what is still waiting for elucidation? (1994)
    Springer
    Journal of bioenergetics and biomembranes 26 (1994), S. 589-598 
    Details
    ISSN: 1573-6881
    Keywords: Chemiosmosis ; Na+ energetics ; flagellar motor ; TonB protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract The present state of the chemiosmotic concept is reviewed. Special attention is paid to (i) further progress in studies on the Na+-coupled energetics and (ii) paradoxical bioenergetic effects when protonic or sodium potentials are utilized outside the coupling membrane (TonB-mediated uphill transports across the outer bacterial membrane). A hypothesis is put forward assuming that the same principle is employed in the bacterial flagellar motor.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00831533
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  • 4
    Electronic Resource
    Electronic Resource
    Anion Carriers in Fatty Acid-Mediated Physiological Uncoupling (1999)
    Springer
    Journal of bioenergetics and biomembranes 31 (1999), S. 431-445 
    Details
    ISSN: 1573-6881
    Keywords: Uncoupling ; thermoregulation ; mitochondria ; ATP/ADP antiporter ; aspartate/glutamate antiporter ; uncoupling proteins 1, 2, 3 ; plant uncoupling protein
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Physiological aspects of uncoupling of oxidation and phosphorylation are reviewed in thecontext of involvement of mitochondrial anion carriers. It is assumed that the carriers facilitateelectrophoretic translation of fatty acid anion, RCOO-, from the inner to the outer leaflet ofthe mitochondrial membrane, whereas back movement of the protonated fatty acid, RCOOH,from the outer to the inner leaflet represents flip-flop of RCOOH via the phospholipid bilayerof the membrane. The RCOO- transport seems to be catalyzed by the ATP/ADP and aspartate/glutamate antiporters, dicarboxylate carrier, and uncoupling proteins (UCP1, UCP2, UCP3L,UCP3s, and plant UCP). The fatty acid uncoupling is shown to be involved in thethermoregulatory heat production in animals and plants exposed to cold, as well as in performance ofrespiratory functions other than ATP synthesis, i.e., formation of useful substances,decomposition of unwanted substances, and antioxidant defense. Moreover, partial uncoupling might takepart in optimization of the rate of ATP synthesis in aerobic cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005492205984
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  • 5
    Electronic Resource
    Electronic Resource
    Bioenergetics: the evolution of molecular mechanisms and the development of bioenergetic concepts (1994)
    Springer
    Antonie van Leeuwenhoek 65 (1994), S. 271-284 
    Details
    ISSN: 1572-9699
    Keywords: bioenergetics ; evolution ; history of science ; H+ cycle ; Na+ cycle ; flagellar motor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Possible routes for the evolution of cell energetics are considered. It is assumed that u.v. light was the primary energy source for the precursors of the primordial living cell and that primitive energetics might have been based on the use of the adenine moiety of ADP as the u.v. chromophore. It is proposed that the excitation of the adenine residue facilitated phosphorylation of its amino group with subsequent transfer of a phosphoryl group to the terminal phosphate of ADP to form ATP. ATP-driven carbohydrate synthesis is considered as a mechanism for storing u.v.-derived energy, which was then used in the dark. Glycolysis presumably produced compounds like ethanol and CO2 which easily penetrate the membrane and therefore were lost by the cell. Later lactate-producing glycolysis appeared, the end product being non-penetrant and, hence, retained inside the cell to be utilized to regenerate carboxydrates when light energy became available. Production of lactate was accompanied by accumulation of equimolar H+. To avoid acidification of the cell interior, an F0-type H+ channel was employed. Later it was supplemented with F1. This allowed the ATP energy to be used for ‘uphill’ H+ pumping to the medium, which was acidified due to glycolytic activity of the cells. In the subsequent course of evolution, u.v. light was replaced by visible light, which has lower energy but is less dangerous for the cell. It is assumed that bacteriorhodopsin, a simple and very stable light-driven H+ pump which still exists in halophilic and thermophilic Archaea, was the primary system utilizing visible light. The $$\Delta \bar \mu _{{\rm H}^ + } $$ formed was used to reverse the H+-ATPase, which began to function as H+-ATP-synthase. Later, bacteriorhodopsin photosynthesis was substituted by a more efficient chlorophyll photosynthesis, producing not only ATP, but also carbohydrates. O2, a side product of this process, was consumed by the H+-motive respiratory chain to form $$\Delta \bar \mu _{{\rm H}^ + } $$ in the dark. At the next stage of evolution, a parallel energy-transducing mechanism appeared which employed Na+ instead of H+ as the coupling ion (the Na+ cycle). As a result, the bioenergetic system became more stable under unfavorable conditions. Apparently, the latest inventions of evolution of biological energy transducers are those which can utilize $$\Delta \bar \mu _{{\rm H}^ + } $$ and $$\Delta \bar \mu _{Na^ + } $$ outside the coupling membrane, like the bacterial flagellar motor and the TonB-mediated uphill transport of solutes across the outer membrane of bacteria.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00872213
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  • 6
    Electronic Resource
    Electronic Resource
    Chemiosmotic systems in bioenergetics: H+-cycles and Na+-cycles (1991)
    Springer
    Bioscience reports 11 (1991), S. 387-444 
    Details
    ISSN: 1573-4935
    Keywords: chemiosmotic action ; H+ cycle ; Na+ cycle ; coupling ion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract The development of membrane bioenergetic studies during the last 25 years has clearly demonstrated the validity of the Mitchellian chemiosmotic H+ cycle concept. The circulation of H+ ions was shown to couple respiration-dependent or light-dependent energy-releasing reactions to ATP formation and performance of other types of membrane-linked work in mitochondria, chloroplasts, some bacteria, tonoplasts, secretory granules and plant and fungal outer cell membranes. A concrete version of the direct chemiosmotic mechanism, in which H+ potential formation is a simple consequence of the chemistry of the energy-releasing reaction, is already proved for the photosynthetic reaction centre complexes. Recent progress in the studies on chemiosmotic systems has made it possible to extend the coupling-ion principle to an ion other than H+. It was found that, in ceertain bacteria, as well as in the outer membrane of the animal cell, Na+ effectively substitutes for H+ as the coupling ion (the chemiosmotic Na+ cycle). A precedent is set when the Na+ cycle appears to be the only mechanism of energy production in the bacterial cell. In the more typical case, however, the H+ and Na+ cycles coexist in one and the same membrane (bacteria) or in two diffeerent membranes of one and the same cell (animals). The sets of $$\Delta \bar \mu H^ + $$ and $$\Delta \bar \mu Na^ + $$ generators as well as $$\Delta \bar \mu H^ + $$ and $$\Delta \bar \mu Na^ + $$ consumers found in different types of biomembranes, are listed and discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01130214
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  • 7
    Electronic Resource
    Electronic Resource
    Membrane-Linked Systems Preventing Superoxide Formation (1997)
    Springer
    Bioscience reports 17 (1997), S. 347-366 
    Details
    ISSN: 1573-4935
    Keywords: Reactive oxygen species ; mitochondria ; pore ; apoptosis ; uncoupling ; non-coupled respiration ; aconitase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: Abstract New facts and ideas concerning the membrane-linked mechanisms preventing superoxide formation are summarised here. It is assumed that aerobic cells possess several lines of anti-ROS defence, including optimisation of the intracellular oxygen concentration, decrease in the concentration and life-time of one-electron O2 reductants such as CoQH; and mitochondrial and cell selections, i.e. elimination of mitochondria and cells producing ROS at high rate. It is postulated that ROS-dependent pore opening and ROS-dependent apoptosis are involved in mitochondrial and cell selections.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1027344914565
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  • 8
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    Effects of lipophilic dications on planar bilayer phospholipid membrane and mitochondria (2007)
    Elsevier
    Details
    Publication Date: 2007-09-01
    Print ISSN: 0005-2728
    Electronic ISSN: 1879-2650
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Published by Elsevier
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  • 9
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    Anion-dependent transition of two acidic forms of bacteriorhodopsin (1989)
    Elsevier
    Details
    Publication Date: 1989-09-01
    Print ISSN: 0005-2728
    Electronic ISSN: 1879-2650
    Topics: Biology , Chemistry and Pharmacology , Medicine , Physics
    Published by Elsevier
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  • 10
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    Mild depolarization of the inner mitochondrial membrane is a crucial component of an anti-aging program (2020)
    National Academy of Sciences
    Details
    Publication Date: 2020-03-09
    Description: The mitochondria of various tissues from mice, naked mole rats (NMRs), and bats possess two mechanistically similar systems to prevent the generation of mitochondrial reactive oxygen species (mROS): hexokinases I and II and creatine kinase bound to mitochondrial membranes. Both systems operate in a manner such that one of the kinase substrates (mitochondrial ATP) is electrophoretically transported by the ATP/ADP antiporter to the catalytic site of bound hexokinase or bound creatine kinase without ATP dilution in the cytosol. One of the kinase reaction products, ADP, is transported back to the mitochondrial matrix via the antiporter, again through an electrophoretic process without cytosol dilution. The system in question continuously supports H+-ATP synthase with ADP until glucose or creatine is available. Under these conditions, the membrane potential, ∆ψ, is maintained at a lower than maximal level (i.e., mild depolarization of mitochondria). This ∆ψ decrease is sufficient to completely inhibit mROS generation. In 2.5-y-old mice, mild depolarization disappears in the skeletal muscles, diaphragm, heart, spleen, and brain and partially in the lung and kidney. This age-dependent decrease in the levels of bound kinases is not observed in NMRs and bats for many years. As a result, ROS-mediated protein damage, which is substantial during the aging of short-lived mice, is stabilized at low levels during the aging of long-lived NMRs and bats. It is suggested that this mitochondrial mild depolarization is a crucial component of the mitochondrial anti-aging system.
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
    Published by National Academy of Sciences
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