A cyclododecadepsipeptide ionophore antibiotic produced by Streptomyces fulvissimus and related to the enniatins. It is composed of 3 moles each of L-valine, D-alpha-hydroxyisovaleric acid, D-valine, and L-lactic acid linked alternately to form a 36-membered ring. (From Merck Index, 11th ed) Valinomycin is a potassium selective ionophore and is commonly used as a tool in biochemical studies.
A polyether antibiotic which affects ion transport and ATPase activity in mitochondria. It is produced by Streptomyces hygroscopicus. (From Merck Index, 11th ed)
Chemical agents that increase the permeability of biological or artificial lipid membranes to specific ions. Most ionophores are relatively small organic molecules that act as mobile carriers within membranes or coalesce to form ion permeable channels across membranes. Many are antibiotics, and many act as uncoupling agents by short-circuiting the proton gradient across mitochondrial membranes.
A proton ionophore. It is commonly used as an uncoupling agent and inhibitor of photosynthesis because of its effects on mitochondrial and chloroplast membranes.
A proton ionophore that is commonly used as an uncoupling agent in biochemical studies.
An element in the alkali group of metals with an atomic symbol K, atomic number 19, and atomic weight 39.10. It is the chief cation in the intracellular fluid of muscle and other cells. Potassium ion is a strong electrolyte that plays a significant role in the regulation of fluid volume and maintenance of the WATER-ELECTROLYTE BALANCE.
A group of peptide antibiotics from BACILLUS brevis. Gramicidin C or S is a cyclic, ten-amino acid polypeptide and gramicidins A, B, D are linear. Gramicidin is one of the two principal components of TYROTHRICIN.
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Stable elementary particles having the smallest known positive charge, found in the nuclei of all elements. The proton mass is less than that of a neutron. A proton is the nucleus of the light hydrogen atom, i.e., the hydrogen ion.
The voltage differences across a membrane. For cellular membranes they are computed by subtracting the voltage measured outside the membrane from the voltage measured inside the membrane. They result from differences of inside versus outside concentration of potassium, sodium, chloride, and other ions across cells' or ORGANELLES membranes. For excitable cells, the resting membrane potentials range between -30 and -100 millivolts. Physical, chemical, or electrical stimuli can make a membrane potential more negative (hyperpolarization), or less negative (depolarization).
Chemical agents that uncouple oxidation from phosphorylation in the metabolic cycle so that ATP synthesis does not occur. Included here are those IONOPHORES that disrupt electron transfer by short-circuiting the proton gradient across mitochondrial membranes.
A carbodiimide that is used as a chemical intermediate and coupling agent in peptide synthesis. (From Hawley's Condensed Chemical Dictionary, 12th ed)
An increase in MITOCHONDRIAL VOLUME due to an influx of fluid; it occurs in hypotonic solutions due to osmotic pressure and in isotonic solutions as a result of altered permeability of the membranes of respiring mitochondria.
The movement of materials across cell membranes and epithelial layers against an electrochemical gradient, requiring the expenditure of metabolic energy.
An element that is an alkali metal. It has an atomic symbol Rb, atomic number 37, and atomic weight 85.47. It is used as a chemical reagent and in the manufacture of photoelectric cells.
An adenine nucleotide containing three phosphate groups esterified to the sugar moiety. In addition to its crucial roles in metabolism adenosine triphosphate is a neurotransmitter.
A member of the alkali group of metals. It has the atomic symbol Na, atomic number 11, and atomic weight 23.
The rate dynamics in chemical or physical systems.
The movement of materials (including biochemical substances and drugs) through a biological system at the cellular level. The transport can be across cell membranes and epithelial layers. It also can occur within intracellular compartments and extracellular compartments.
Used as an electron carrier in place of the flavine enzyme of Warburg in the hexosemonophosphate system and also in the preparation of SUCCINIC DEHYDROGENASE.
Artificial, single or multilaminar vesicles (made from lecithins or other lipids) that are used for the delivery of a variety of biological molecules or molecular complexes to cells, for example, drug delivery and gene transfer. They are also used to study membranes and membrane proteins.
Red dye, pH indicator, and diagnostic aid for determination of renal function. It is used also for studies of the gastrointestinal and other systems.
Inorganic compounds derived from hydrochloric acid that contain the Cl- ion.
A quality of cell membranes which permits the passage of solvents and solutes into and out of cells.
Mitochondria in hepatocytes. As in all mitochondria, there are an outer membrane and an inner membrane, together creating two separate mitochondrial compartments: the internal matrix space and a much narrower intermembrane space. In the liver mitochondrion, an estimated 67% of the total mitochondrial proteins is located in the matrix. (From Alberts et al., Molecular Biology of the Cell, 2d ed, p343-4)
A polypeptide antibiotic mixture obtained from Bacillus brevis. It consists of a mixture of three tyrocidines (60%) and several gramicidins (20%) and is very toxic to blood, liver, kidneys, meninges, and the olfactory apparatus. It is used topically.
A closely related group of toxic substances elaborated by various strains of Streptomyces. They are 26-membered macrolides with lactone moieties and double bonds and inhibit various ATPases, causing uncoupling of phosphorylation from mitochondrial respiration. Used as tools in cytochemistry. Some specific oligomycins are RUTAMYCIN, peliomycin, and botrycidin (formerly venturicidin X).
Energy that is generated by the transfer of protons or electrons across an energy-transducing membrane and that can be used for chemical, osmotic, or mechanical work. Proton-motive force can be generated by a variety of phenomena including the operation of an electron transport chain, illumination of a PURPLE MEMBRANE, and the hydrolysis of ATP by a proton ATPase. (From Singleton & Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d ed, p171)
Positively charged atoms, radicals or group of atoms with a valence of plus 1, which travel to the cathode or negative pole during electrolysis.
Protein-lipid combinations abundant in brain tissue, but also present in a wide variety of animal and plant tissues. In contrast to lipoproteins, they are insoluble in water, but soluble in a chloroform-methanol mixture. The protein moiety has a high content of hydrophobic amino acids. The associated lipids consist of a mixture of GLYCEROPHOSPHATES; CEREBROSIDES; and SULFOGLYCOSPHINGOLIPIDS; while lipoproteins contain PHOSPHOLIPIDS; CHOLESTEROL; and TRIGLYCERIDES.
Ions with the suffix -onium, indicating cations with coordination number 4 of the type RxA+ which are analogous to QUATERNARY AMMONIUM COMPOUNDS (H4N+). Ions include phosphonium R4P+, oxonium R3O+, sulfonium R3S+, chloronium R2Cl+
Thin structures that encapsulate subcellular structures or ORGANELLES in EUKARYOTIC CELLS. They include a variety of membranes associated with the CELL NUCLEUS; the MITOCHONDRIA; the GOLGI APPARATUS; the ENDOPLASMIC RETICULUM; LYSOSOMES; PLASTIDS; and VACUOLES.
The study of chemical changes resulting from electrical action and electrical activity resulting from chemical changes.
Electron transfer through the cytochrome system liberating free energy which is transformed into high-energy phosphate bonds.
Compounds that contain three methine groups. They are frequently used as cationic dyes used for differential staining of biological materials.
The lipid- and protein-containing, selectively permeable membrane that surrounds the cytoplasm in prokaryotic and eukaryotic cells.
A white crystal or crystalline powder used in BUFFERS; FERTILIZERS; and EXPLOSIVES. It can be used to replenish ELECTROLYTES and restore WATER-ELECTROLYTE BALANCE in treating HYPOKALEMIA.
A group of enzymes which catalyze the hydrolysis of ATP. The hydrolysis reaction is usually coupled with another function such as transporting Ca(2+) across a membrane. These enzymes may be dependent on Ca(2+), Mg(2+), anions, H+, or DNA.
Multisubunit enzymes that reversibly synthesize ADENOSINE TRIPHOSPHATE. They are coupled to the transport of protons across a membrane.
Macrolide antifungal antibiotic complex produced by Streptomyces noursei, S. aureus, and other Streptomyces species. The biologically active components of the complex are nystatin A1, A2, and A3.
An antibiotic substance produced by Streptomyces species. It inhibits mitochondrial respiration and may deplete cellular levels of ATP. Antimycin A1 has been used as a fungicide, insecticide, and miticide. (From Merck Index, 12th ed)
Derivatives of SUCCINIC ACID. Included under this heading are a broad variety of acid forms, salts, esters, and amides that contain a 1,4-carboxy terminated aliphatic structure.
The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)
The mitochondria of the myocardium.
The movement of ions across energy-transducing cell membranes. Transport can be active, passive or facilitated. Ions may travel by themselves (uniport), or as a group of two or more ions in the same (symport) or opposite (antiport) directions.
Compounds consisting of chains of AMINO ACIDS alternating with CARBOXYLIC ACIDS via ester and amide linkages. They are commonly cyclized.
Semiautonomous, self-reproducing organelles that occur in the cytoplasm of all cells of most, but not all, eukaryotes. Each mitochondrion is surrounded by a double limiting membrane. The inner membrane is highly invaginated, and its projections are called cristae. Mitochondria are the sites of the reactions of oxidative phosphorylation, which result in the formation of ATP. They contain distinctive RIBOSOMES, transfer RNAs (RNA, TRANSFER); AMINO ACYL T RNA SYNTHETASES; and elongation and termination factors. Mitochondria depend upon genes within the nucleus of the cells in which they reside for many essential messenger RNAs (RNA, MESSENGER). Mitochondria are believed to have arisen from aerobic bacteria that established a symbiotic relationship with primitive protoeukaryotes. (King & Stansfield, A Dictionary of Genetics, 4th ed)
Inorganic or organic salts and esters of arsenic acid.
An anionic compound that is used as a reagent for determination of potassium, ammonium, rubidium, and cesium ions. It also uncouples oxidative phosphorylation and forms complexes with biological materials, and is used in biological assays.
Negatively charged atoms, radicals or groups of atoms which travel to the anode or positive pole during electrolysis.
The process by which ELECTRONS are transported from a reduced substrate to molecular OXYGEN. (From Bennington, Saunders Dictionary and Encyclopedia of Laboratory Medicine and Technology, 1984, p270)
The first chemical element in the periodic table. It has the atomic symbol H, atomic number 1, and atomic weight [1.00784; 1.00811]. It exists, under normal conditions, as a colorless, odorless, tasteless, diatomic gas. Hydrogen ions are PROTONS. Besides the common H1 isotope, hydrogen exists as the stable isotope DEUTERIUM and the unstable, radioactive isotope TRITIUM.
Inorganic salts of HYDROGEN CYANIDE containing the -CN radical. The concept also includes isocyanides. It is distinguished from NITRILES, which denotes organic compounds containing the -CN radical.
Minute projections of cell membranes which greatly increase the surface area of the cell.
The use of light to convert ADP to ATP without the concomitant reduction of dioxygen to water as occurs during OXIDATIVE PHOSPHORYLATION in MITOCHONDRIA.
A basic element found in nearly all organized tissues. It is a member of the alkaline earth family of metals with the atomic symbol Ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes.
Property of membranes and other structures to permit passage of light, heat, gases, liquids, metabolites, and mineral ions.

Induction of apoptosis by valinomycin: mitochondrial permeability transition causes intracellular acidification. (1/716)

In order to determine whether disruption of mitochondrial function could trigger apoptosis in murine haematopoietic cells, we used the potassium ionophore valinomycin. Valinomycin induces apoptosis in the murine pre-B cell line BAF3, which cannot be inhibited by interleukin-3 addition or Bcl-2 over-expression. Valinomycin triggers rapid loss of mitochondrial membrane potential. This precedes cytoplasmic acidification, which leads to cysteine-active-site protease activation, DNA fragmentation and cell death. Bongkrekic acid, an inhibitor of the mitochondrial permeability transition, prevents acidification and subsequent induction of apoptosis by valinomycin.  (+info)

Sodium-dependent glutamate uptake by an alkaliphilic, thermophilic Bacillus strain, TA2.A1. (2/716)

A strain of Bacillus designated TA2.A1, isolated from a thermal spring in Te Aroha, New Zealand, grew optimally at pH 9.2 and 70 degrees C. Bacillus strain TA2.A1 utilized glutamate as a sole carbon and energy source for growth, and sodium chloride (>5 mM) was an obligate requirement for growth. Growth on glutamate was inhibited by monensin and amiloride, both inhibitors that collapse the sodium gradient (DeltapNa) across the cell membrane. N, N-Dicyclohexylcarbodiimide inhibited the growth of Bacillus strain TA2.A1, suggesting that an F1F0-ATPase (H type) was being used to generate cellular ATP needed for anabolic reactions. Vanadate, an inhibitor of V-type ATPases, did not affect the growth of Bacillus strain TA2.A1. Glutamate transport by Bacillus strain TA2.A1 could be driven by an artificial membrane potential (DeltaPsi), but only when sodium was present. In the absence of sodium, the rate of DeltaPsi-driven glutamate uptake was fourfold lower. No glutamate transport was observed in the presence of DeltapNa alone (i.e., no DeltaPsi). Glutamate uptake was specifically inhibited by monensin, and the Km for sodium was 5.6 mM. The Hill plot had a slope of approximately 1, suggesting that sodium binding was noncooperative and that the glutamate transporter had a single binding site for sodium. Glutamate transport was not affected by the protonophore carbonyl cyanide m-chlorophenylhydrazone, suggesting that the transmembrane pH gradient was not required for glutamate transport. The rate of glutamate transport increased with increasing glutamate concentration; the Km for glutamate was 2.90 microM, and the Vmax was 0.7 nmol. min-1 mg of protein. Glutamate transport was specifically inhibited by glutamate analogues.  (+info)

The protein import motor of mitochondria: unfolding and trapping of preproteins are distinct and separable functions of matrix Hsp70. (3/716)

Mitochondrial heat shock protein 70 (mtHsp70) functions in unfolding, translocation, and folding of imported proteins. Controversial models of mtHsp70 action have been discussed: (1) physical trapping of preproteins is sufficient to explain the various mtHsp70 functions, and (2) unfolding of preproteins requires an active motor function of mtHsp70 ("pulling"). Intragenic suppressors of a mutant mtHsp70 separate two functions: a nonlethal folding defect caused by enhanced trapping of preproteins, and a conditionally lethal unfolding defect caused by an impaired interaction of mtHsp70 with the membrane anchor Tim44. Even enhanced trapping in wild-type mitochondria does not generate a pulling force. The motor function of mtHsp70 cannot be explained by passive trapping alone but includes an essential ATP-dependent interaction with Tim44 to generate a pulling force and unfold preproteins.  (+info)

-->H+/2e- stoichiometry in NADH-quinone reductase reactions catalyzed by bovine heart submitochondrial particles. (4/716)

Tightly coupled bovine heart submitochondrial particles treated to activate complex I and to block ubiquinol oxidation were capable of rapid uncoupler-sensitive inside-directed proton translocation when a limited amount of NADH was oxidized by the exogenous ubiquinone homologue Q1. External alkalization, internal acidification and NADH oxidation were followed by the rapidly responding (t1/2 < or = 1 s) spectrophotometric technique. Quantitation of the initial rates of NADH oxidation and external H+ decrease resulted in a stoichiometric ratio of 4 H+ vectorially translocated per 1 NADH oxidized at pH 8.0. ADP-ribose, a competitive inhibitor of the NADH binding site decreased the rates of proton translocation and NADH oxidation without affecting -->H+/2e- stoichiometry. Rotenone, piericidin and thermal deactivation of complex I completely prevented NADH-induced proton translocation in the NADH-endogenous ubiquinone reductase reaction. NADH-exogenous Q1 reductase activity was only partially prevented by rotenone. The residual rotenone- (or piericidin-) insensitive NADH-exogenous Q1 reductase activity was found to be coupled with vectorial uncoupler-sensitive proton translocation showing the same -->H+/2e- stoichiometry of 4. It is concluded that the transfer of two electrons from NADH to the Q1-reactive intermediate located before the rotenone-sensitive step is coupled with translocation of 4 H+.  (+info)

ATP-sensitive K+ channel openers prevent Ca2+ overload in rat cardiac mitochondria. (5/716)

1. Mitochondrial dysfunction, secondary to excessive accumulation of Ca2+, has been implicated in cardiac injury. We here examined the action of potassium channel openers on mitochondrial Ca2+ homeostasis, as these cardioprotective ion channel modulators have recently been shown to target a mitochondrial ATP-sensitive K+ channel. 2. In isolated cardiac mitochondria, diazoxide and pinacidil decreased the rate and magnitude of Ca2+ uptake into the mitochondrial matrix with an IC50 of 65 and 128 microM, respectively. At all stages of Ca2+ uptake, the potassium channel openers depolarized the mitochondrial membrane thereby reducing Ca2+ influx through the potential-dependent mitochondrial uniporter. 3. Diazoxide and pinacidil, in a concentration-dependent manner, also activated release of Ca2+ from mitochondria. This was prevented by cyclosporin A, an inhibitor of Ca2+ release through the mitochondrial permeability transition pore. 4. Replacement of extramitochondrial K+ with mannitol abolished the effects of diazoxide and pinacidil on mitochondrial Ca2+, while the K+ ionophore valinomycin mimicked the effects of the potassium channel openers. 5. ATP and ADP, which block K+ flux through mitochondrial ATP-sensitive K+ channels, inhibited the effects of potassium channel openers, without preventing the action of valinomycin. 6. In intact cardiomyocytes, diazoxide also induced mitochondrial depolarization and decreased mitochondrial Ca2+ content. These effects were inhibited by the mitochondrial ATP-sensitive K+ channel blocker 5-hydroxydecanoic acid. 7. Thus, potassium channel openers prevent mitochondrial Ca2+ overload by reducing the driving force for Ca2+ uptake and by activating cyclosporin-sensitive Ca2+ release. In this regard, modulators of an ATP-sensitive mitochondrial K+ conductance may contribute to the maintenance of mitochondrial Ca2+ homeostasis.  (+info)

Signal-dependent phosphorylation of the membrane-bound NarX two-component sensor-transmitter protein of Escherichia coli: nitrate elicits a superior anion ligand response compared to nitrite. (6/716)

The Nar two-component regulatory system, consisting of the dual sensor-transmitters NarX and NarQ and the dual response regulators NarL and NarP, controls the expression of various anaerobic respiratory pathway genes and fermentation pathway genes. Although both NarX and NarQ are known to detect the two environmental signals nitrate and nitrite, little is known regarding the sensitivity and selectivity of ligand for detection or activation of the sensor-transmitters. In this study, we have developed a sensitive anion-specific in vitro assay for NarX autophosphorylation by using Escherichia coli membranes highly enriched in the full-length NarX protein. In this ATP- and magnesium-dependent reaction, nitrate elicited a greater signal output (i.e., NarX autophosphorylation) than did nitrite. Nitrate stimulation occurred at concentrations as low as 5 microM, and the half-maximal level of NarX autophosphorylation occurred at approximately 35 microM nitrate. In contrast, nitrite-dependent stimulation was detected only at 500 microM, while 3.5 mM nitrite was needed to achieve half-maximal NarX autophosphorylation. Maximal nitrate- and nitrite-stimulated levels of NarX phosphorylation were five and two times, respectively, over the basal level of NarX autophosphorylation. The presence of Triton X-100 eliminated the nitrate-stimulated kinase activity and lowered the basal level of activity, suggesting that the membrane environment plays a crucial role in nitrate detection and/or regulation of kinase activity. These results provide in vitro evidence for the differential detection of dual signaling ligands by the NarX sensor-transmitter protein, which modulates the cytoplasmic NarX autokinase activity and phosphotransfer to NarL, the cognate response regulator.  (+info)

Depolarization-mediated inhibition of Ca(2+) entry in endothelial cells. (7/716)

The effect of extracellular Cl(-) in regulating ACh-induced Ca(2+) entry into freshly isolated rabbit aortic endothelial cells was studied using Ca(2+)-sensitive fluorescence microscopy and patch-clamp electrophysiology. After ACh caused transient Ca(2+) release in Ca(2+)-free medium, readdition of 3 mM Ca(2+) to the bath maintained Ca(2+) entry. Removal of extracellular Cl(-) abolished the plateau phase in Ca(2+) signal and inhibited divalent cation entry. However, in the presence of the K(+) ionophore valinomycin, removal of Cl(-) had no effect on the Ca(2+) plateau. Under current-clamp conditions, substitution of gluconate for Cl(-) induced membrane depolarization. Under voltage clamp, with CsCl in the pipette, ACh activated a slowly developing Cl(-) current, which was blocked by SITS and 5-nitro-2-(3-phenylpropylamino)benzoic acid. Varying the membrane potential by utilizing different extracellular K(+) concentrations in the presence of 5 microM valinomycin demonstrated that depolarization blocked ACh-stimulated Mn(2+) entry. These data suggest that ACh-induced Ca(2+) entry in freshly isolated endothelial cells requires the presence of extracellular Cl(-) to maintain a polarized membrane potential.  (+info)

Butyrate-induced apoptotic cascade in colonic carcinoma cells: modulation of the beta-catenin-Tcf pathway and concordance with effects of sulindac and trichostatin A but not curcumin. (8/716)

Short-chain fatty acids play a critical role in colonic homeostasis because they stimulate pathways of growth arrest, differentiation, and apoptosis. These effects have been well characterized in colonic cell lines in vitro. We investigated the role of beta-catenin-Tcf signaling in these responses to butyrate and other well-characterized inducers of apoptosis of colonic epithelial cells. Unlike wild-type APC, which down-regulates Tcf activity, butyrate, as well as sulindac and trichostatin A, all inducers of G0-G1 cell cycle arrest and apoptosis in the SW620 colonic carcinoma cell line, up-regulate Tcf activity. In contrast, structural analogues of butyrate that do not induce cell cycle arrest or apoptosis and curcumin, which stimulates G2-M arrest without inducing apoptosis, do not alter Tcf activity. Similar to the cell cycle arrest and apoptotic cascade induced by butyrate, the up-regulation of Tcf activity is dependent upon the presence of a mitochondrial membrane potential, unlike the APC-induced down-regulation, which is insensitive to collapse of the mitochondrial membrane potential. Moreover, the butyrate-induced increase in Tcf activity, which is reflected in an increase in beta-catenin-Tcf complex formation, is independent of the down-regulation caused by expression of wild-type APC. Thus, butyrate and wild-type APC have different and independent effects on beta-catenin-Tcf signaling. These data are consistent with other reports that suggest that the absence of wild-type APC, associated with the up-regulation of this signaling pathway, is linked to the probability of a colonic epithelial cell entering an apoptotic cascade.  (+info)

A cyclic depsipeptide antibiotic, valinomycin, was found to produce increased selective permeability of the plasma membranes of HK and LK sheep red blood cells to potassium but not to sodium ions. The compound had relatively little effect on the active extrusion of sodium from HK sheep red blood cells or on the Na + K-stimulated ATPase activity of membranes derived from these cells. It is proposed that the selective cation permeability produced by this compound depends primarily on steric factors, particularly the relationship between the diameter of the ring and the effective diameter of the ion. The significance of these results for the problem of the mechanism of ionic selectivity in natural membranes is discussed.. ...
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A cyclododecadepsipeptide ionophore antibiotic produced by Streptomyces fulvissimus and related to the enniatins. It is composed of 3 moles each of L-valine, D-alpha-hydroxyisovaleric acid, D-valine, and L-lactic acid linked alternately to form a 36-membered ring. (From Merck Index, 11th ed) Valinomycin is a potassium selective ionophore and is commonly used as a tool in biochemical studies ...
A molecule that allows ions to cross lipid bilayers. There are two classes: carriers and channels. Carriers, like valinomycin, form cage like structures around specific ions, diffusing freely through the hydrophobic regions of the bilayer.…
1. The properties of membrane vesicles from the extreme thermophile Bacillus caldolyticus were investigated. 2. Vesicles prepared by exposure of spheroplasts to ultrasound contained cytochromes a, b and c, and at 50°C they rapidly oxidized NADH and ascorbate in the presence of tetramethyl-p-phenylenediamine. Succinate and l-malate were oxidized more slowly, and dl-lactate, l-alanine and glycerol 1-phosphate were not oxidized. 3. In the absence of proton-conducting uncouplers the oxidation of NADH was accompanied by a net translocation of H+ into the vesicles. Hydrolysis of ATP by a dicyclohexylcarbodi-imide-sensitive adenosine triphosphatase was accompanied by a similarly directed net translocation of H+. 4. Uncouplers (carbonyl cyanide p-trifluoromethoxyphenylhydrazone or valinomycin plus NH4+) prevented net H+ translocation but stimulated ATP hydrolysis, NADH oxidation and ascorbate oxidation. The last result suggested an energy-conserving site in the respiratory chain between cytochrome c ...
a) Spectrum obtained from the Hybrid Plate. (b) Spectrum obtained from plate by contact plate pressing. Figure 27 Spectra Obtained for 4.5 pmol of Valinomycin from the Hybrid Plate and by Contact Pressing Transfer. After separation, the plate (now acting as a transport system) was transferred to the laser desorption mass spectrometer source and spectra taken in the usual manner. The spectrum obtained form the Valinomycin spot is shown in figure 27, where the results from the hybrid plate are compared with the more conventional contact pressing transfer procedure.. It is clear from figure 27 that the employment of the hybrid plate increases the signal to noise ratio significantly and, consequently, increases the sensitivity of the overall system by an order of magnitude or more. For quantitative work it is clear that an external standard will be necessary and the precision of quantitative assays is not reported. However, the technique offers the possibility of very high sensitivity, specific ...
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TY - JOUR. T1 - Increased valinomycin production in mutants of Streptomyces sp. M10 defective in bafilomycin biosynthesis and branched-chain α-keto acid dehydrogenase complex expression. AU - Lee, Dong Wan. AU - Ng, Bee Gek. AU - Kim, Beom Seok. N1 - Publisher Copyright: © 2015, Society for Industrial Microbiology and Biotechnology.. PY - 2015/11/1. Y1 - 2015/11/1. N2 - Streptomyces sp. M10 is a valinomycin-producing bacterial strain that shows potent bioactivity against Botrytis blight of cucumber plants. During studies to increase the yield of valinomycin (a cyclododecadepsipeptide) in strain M10, additional antifungal metabolites, including bafilomycin derivatives (macrolide antibiotics), were identified. To examine the effect of bafilomycin biosynthesis on valinomycin production, the bafilomycin biosynthetic gene cluster was cloned from the genome of strain M10, as were two branched-chain α-keto acid dehydrogenase (BCDH) gene clusters related to precursor supply for bafilomycin ...
MILE LONG POST-IT 2008-2017 ResearchGate GmbH. great valuable download proton Britons describe Taken through the process of MANY contact and traditional conditions. Below you will find the measures intended by the British Columbia Resource Estimate Mapping download proton conductors was identifying the NTS( National Topographic System) everytime mica Indicators about proposed throughout Canada. The download proton conductors affects conducted buried oceanic to you to warehouse and field; for economic, Academic and order extent in printing to refer and begin 22(1 success S&. SummaryThe NTS download proton conductors is a supply that is a dynamo issue of 15 fix and Organizational; land that makes British Columbia into exclusive geochemistry signals. The difficult objective download proton conductors does been for each of the table nations blowing a bold heating skin replacement, and only the not-for-profit mortality in the morphology is triggered by indicating almost the average priests of each ...
Cell line-dependent increase in cellular quercetin accumulation upon stress induced by valinomycin and lipopolysaccharide, but not by TNF-α (2019) Hanne Vissenaekens (UGent), Charlotte Grootaert (UGent), Andreja Rajkovic (UGent), Kristof De Schutter (UGent), Katleen Raes (UGent), Guy Smagghe (UGent), Tom Van de Wiele (UGent), John Van Camp (UGent ...
Many are directed against functional se- creted molecules of the immune system or their receptors, rather than against buy Snovitra groups of cells. 233.
The Institute of Diabetes Research of the Helmholtz Zentrum München has now registered 100,000 participants in the Bavarian study Fr1da on the early detection of type 1 diabetes. The study will be continued with an additional age group under the name Fr1da-plus: in addition to 2 to 5-year-olds, 9 and 10-year-old children can now also participate in the study.
Read Influence of electrochemical proton gradient on electron flow in photosystem I of pea leaves, Russian Journal of Plant Physiology on DeepDyve, the largest online rental service for scholarly research with thousands of academic publications available at your fingertips.
Uptake of SO42− into brush-border membrane vesicles isolated from rat kindey cortex by a Ca2+-precipitation method was investigated by using a rapid-filtration technique. Uptake of SO42− by the vesicles was osmotically sensitive and represented transport into an intra-vesicular space. Transport of SO42− by brush-border membranes was stimulated in the presence of Na+, compared with the presence of K+ or other univalent cations. A typical overshoot phenomenon was observed in the presence of an NaCl gradient (100mm-Na+ outside/zero mm-Na+ inside). Radioactive-SO42− exchange was faster in the presence of Na+ than in the presence of K+. Addition of gramicidin-D, an ionophore for univalent cations, decreased the Na+-gradient-driven SO42− uptake. SO42− uptake was only saturable in the presence of Na+. Counter-transport of Na+-dependent SO42− transport was shown with MoO42− and S2O32−, but not with PO42−. Changing the electrical potential difference across the vesicle membrane by ...
The protonmotive force, ∆mFH+, is known as Δp in Peter Mitchells chemiosmotic theory [1], which establishes the link between electric and chemical components of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the pmF ranks among the most fundamental theories in biology. As such, it provides the framework for developing a consistent theory and nomenclature for mitochondrial physiology and bioenergetics. The protonmotive force is not a vector force as defined in physics. This conflict is resolved by the generalized formulation of isomorphic, compartmental forces, ∆trF, in energy (exergy) transformations [2]. Protonmotive means that there is a potential for the movement of protons, and force is a measure of the potential for motion. The pmF is generated in oxidative phosphorylation by oxidation of reduced fuel substrates and reduction of O2 to H2O, driving the coupled proton translocation from the mt-matrix space across the mitochondrial inner membrane ...
1. The respiration of rat liver mitochondria was compared with different substrates, and with sucrose and saline media. The maximum rates of oxidation obtainable from glutamate, oxoglutarate, glutamate+malate, or succinate were higher in the saline (120mm)-tris (20mm) media than in sucrose (250mm)-tris (20mm) mixtures, but the rate with β-hydroxybutyrate was unchanged. Addition of valinomycin to a medium with sucrose and 5mm-potassium chloride led to rates similar to those measured in saline media; β-hydroxybutyrate oxidation was unaffected. 2. Some pairs of substrates together provided a rate of oxidation greater than the sum of the separate rates. This is accountable if removal of inhibitory products, such as oxaloacetate, compensates for any mutual competition between the substrates. Other pairs showed rates less than the sum of the separate rates, which is accountable by mutual competition. β-Hydroxybutyrate and other substrates, except succinate, provided strictly additive rates; with ...
An uncoupler is a protonophore (CCCP, FCCP, DNP) which cycles across the inner mt-membrane with transport of protons and dissipation of the electrochemical proton gradient. Mild uncoupling may be induced at low uncoupler concentrations, the noncoupled state of ET capacity is obtained at optimum uncoupler concentration for maximum flux, whereas at higher concentrations an uncoupler-induced inhibition is observed. Abbreviation: U Reference: Noncoupled respiration ...
E Coli ArsAB ATPase: ArsA and ArsB they form the As(III)-translocating ArsAB ATPase, which is independent of the electrochemical proton gradient
Owing to missing core electrons protons play a special role amongst ionically conducting materials. They are rather transported by the environment (vehicles, phonons) and may exhibit strong correlation effects and often extreme mobilities.. ...
Cytotoxicity of weak electrolytes after the adaptation of cells to low pH: role of the transmembrane pH gradient. Br J Cancer. 1998 May; 77(10):1580-5 ...
NAD(P)H-FLIM; respirometry; energy metabolism; mitochondria; matrix pH; redox state; fluorescence lifetime; intracellular ph; in-vivo; energy-metabolism; nadh fluorescence; cells; autofluorescence; microscopy; ...
Compare Bet1 golgi vesicular membrane trafficking protein like ELISA Kits from leading suppliers on Biocompare. View specifications, prices, citations, reviews, and more.
The information in this website is for educational purposes only and not to be construed as medical advice. It is not meant to diagnose, prescribe, or in any way replace qualified medical supervision. For any medical conditions, consult with your healthcare provider before using any products. Peace and love to all ...
The effects of pH gradients on the uptake and distribution of C14-procaine and lidocaine in intact and desheathed sciatic nerve trunks.:
The plasmoelectric effect: optically induced electrochemical potentials in resonant metallic structures Matthew T. Sheldon and Harry A. Atwater Thomas J. Watson Laboratories of Applied Physics, California
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The effects of guanosine 5-triphosphate (GTP) and GTP-gamma-S, known activators of GTP binding proteins, on proton transport were investigated in endosome-enriched vesicles (endosomes). Endosomes were prepared from rabbit renal cortex following the intravenous injection of FITC-dextran. The rate of intravesicular acidification was determined by measuring changes in fluorescence of FITC-dextran. Both GTP and GTP-gamma-S stimulated significantly the initial rate of proton transport. In contrast, GDP-beta-S, which does not activate GTP binding proteins, inhibited proton transport. The rank order of stimulation was GTP-gamma-S greater than GTP greater than control greater than GDP-beta-S. GTP-gamma-S stimulation of proton transport was also observed under conditions in which chloride entry was eliminated, i.e., 0 mM external chloride concentration in the presence of potassium/valinomycin voltage clamping. GTP-gamma-S did not affect proton leak in endosomes as determined by collapse of H+ ...
Mitochondrial and plasma membrane potential of cultured cerebellar neurons during glutamate-induced necrosis, apoptosis, and tolerance.
Principal Investigator:YAMANAKA Shinsuke, Project Period (FY):1993 - 1994, Research Category:Grant-in-Aid for General Scientific Research (C), Research Field:Nuclear fusion studies
In pyroptosis experiments, nigericin can be used as a positive control to generate a robust caspase-1 activation response in a variety of cell lines.
Looking for online definition of Proton-motive force in the Medical Dictionary? Proton-motive force explanation free. What is Proton-motive force? Meaning of Proton-motive force medical term. What does Proton-motive force mean?
The Section for Proton Conductors focuses on materials science and electrochemical systems and components based on proton conducting cells in a broad sense, at low to intermediate temperature (below 400 °C). The electrolytes include direct proton conductors as well as indirect proton conductors like aqueous hydroxide. Research also encompasses electrocatalysis and development of complete cells around proton conducting electrolytes.. We synthesize polymers and manufacture and characterize proton conducting membranes. Special attention is devoted to high temperature membranes (polybenzimidazole, PBI) with chemical stability in acid as well as in base. Such polymers have been successfully applied in high-temperature PEM fuel cells, a research field in which we are pioneers. Lately, similar membranes have been successfully applied in alkaline electrolysis cells. Solid or liquid inorganic proton conductors are also studied for electrolysis above 200 °C. Within electrocatalysis our research focus is ...
The strategy applied in the structure refinement of accurate single-crystal neutron diffraction data for pseudo-centrosymmetric proton conducting systems can often be decisive. The application of a combination of judicious symmetry constraints and symmet. ...
In all cross-shore gradient-dependent mortality models the mortality function M was determined either by the cross-shore location of the particle (ADG), or by the cross-shore location of the particle and scaled solar insolation (ADGI). The cross-shore dependence of M was similar to the horizontal diffusion function used in all models (Eq. (1)): equation(8) ADG model:M=m1+m0-m121-tanhy-y0yscale equation(9) ADGI model:M=I(t)Imaxm1+m0-m121-tanhy-y0yscalewhere. m0 is surfzone mortality, m1 is offshore mortality, y0 is the offshore edge of the surfzone, and yscale determines the cross-shore scale of the surfzone/offshore transition. Values for y0 and yscale BGJ398 mouse were 50 m and 5 m, respectively, the same values used to parameterize diffusivity (Eq. (1)). Note that in the ADG and ADGI models, mortality is not an intrinsic property of a given particle (as in the ADS and ADSI models). Instead, particles move through stationary cross-shore mortality gradients and take on different mortality rates ...
Proposes the law of motive force as a fundamental law of nature and establishes its relation to other laws and principles in thermodynamics With the aid
BAM15, ST056388, mitochondrial protonophore uncoupler that does not depolarize the plasma membrane IDNUMBER ST056388 Other identifiers: SBB001916, ST4027337, T4021910, TBB011486, T3149443, ST236891 Formula: C16H10F2N6O MW: 340. 29 NAME: (2-fluorophenyl)amine SMILES: c12c(nc(c(n1)Nc1c(F)cccc1)Nc1c(F)cccc1)non2 InChI=1S/C16H10F2N6O/c17-9-5-1-3-7-11(9)19-13-14(20-12-8-4-2-6-10(12)18)22-16-15(21-13)23-25-24-16/h1-8H,(H,19,21,23)(H,20,22,24) InChIKey=OEGJBRZAJRPPHL-UHFFFAOYSA-N MDL: MFCD00373912 Contact us to order....
Anion effects on valinomycin-cation complexes". Journal of the American Chemical Society. 104 (15): 4085-4091. doi:10.1021/ ... An example of a carrier ionophore is valinomycin, a molecule that transports a single potassium cation. Carrier ionophores may ... Thompson, Michael; Krull, U.J. (September 1982). "The electroanalytical response of the bilayer lipid membrane to valinomycin: ... Steinrauf, L. K.; Hamilton, J. A.; Sabesan, M. N. (1982). "Crystal structure of valinomycin-sodium picrate. ...
... produces the ionophore valinomycin. List of Streptomyces species LPSN bacterio.net Straininfo of ...
... is a cyclic dodecadepsipeptide resembling valinomycin; it contains three repeats of four amino acids: D-Oxy-Leu-D-Ala ...
... can be used for valinomycin biosynthesis. Braña, AF; Fiedler, HP; Nava, H; González, V; Sarmiento- ...
Devarajan, S.; Nair, C.M.K.; Easwaran, K.R.K.; Vijayan, M. (7 August 1980). "A novel conformation of valinomycin in its barium ...
Transport Mediated by Valinomycin-like Carriers". Chem. 1 (1): 127-146. doi:10.1016/j.chempr.2016.04.002. "Clarivate Analytics ...
Other compounds containing D-amino acids are tyrocidine and valinomycin. These compounds disrupt bacterial cell walls, ...
For example, a K+ sensor was produced by incorporating valinomycin into a thin membrane. In 1953, Watson and Crick announced ...
Rose L, Jenkins AT (2006). "The effect of the ionophore valinomycin on biomimetic solid supported lipid DPPTE/EPC membranes". ...
... a potassium ion-selective membrane electrode utilizes the naturally occurring macrocyclic antibiotic valinomycin. In this case ...
For example, an electrode based on Valinomycin may be used for the determination of potassium ion concentration. Fluoride ... based on valinomycin as an ion-exchange agent. Enzyme electrodes definitely are not true ion-selective electrodes but usually ...
This ion selectivity is seen in other macrocyclic ligands, such as the cyclic ionophore valinomycin, which is also an ... "Freezing and Melting of Lipid Bilayers and the Mode of Action of Nonactin, Valinomycin, and Gramicidin." Freezing and Melting ... of Lipid Bilayers and the Mode of Action of Nonactin, Valinomycin, and Gramicidin. Sigma-Aldrich, n.d. Web.] [Total synthesis ...
Ionophores such as valinomycin also display a marked preference for the potassium cation over other cations. Crown ethers have ...
... effects on energized ion fluxes in the presence of valinomycin". Biochemical Pharmacology. 24 (18): 1701-1705. doi:10.1016/0006 ...
M. B. Sankaram, K. R. K. Easwaran (August 1982). "CD and nmr studies on the interaction of lithium ion with valinomycin and ...
Effects on Energized Ion Fluxes in the Presence of Valinomycin". Biochemical Pharmacology. 24 (18): 1701-5. doi:10.1016/0006- ...
... effects on energized ion fluxes in the presence of valinomycin". Biochemical Pharmacology. 24 (18): 1701-1705. doi:10.1016/0006 ...
"Action of propranolol on mitochondrial functions-effects on energized ion fluxes in the presence of valinomycin". Biochemical ...
Third, Mg2+ efflux was observed via Mrs2p upon the artificial depolarisation of the mitochondrial membrane by valinomycin. ...
... potassium selective electrodes are available that make use of the naturally occurring macrocyclic antibiotic valinomycin. An ...
Synthesis of analogs of valinomycin with modified side chains and different contents of amide and ester groups, Chem Nat Compd ... Relation between structure and properties of cyclodepsipep-tides of valinomycin series, Russ Chem Bull 23, 2225-2232 (1974). ... Synthesis of new analogs of valinomycin and their properties, I. Chem Nat Compd 10, 238-243 (1974). https://doi.org/10.1007/ ... and antimicrobial activity in a series of analogs of valinomycin, Chem Nat Compd 9, 229-234 (1973). https://doi.org/10.1007/ ...
Applying ionophores like valinomycin can create electrochemical gradients comparable to the gradients inside living cells. ...
These electrodes are typical ion exchange resin membrane electrodes, using valinomycin, a potassium ionophore, as the ion ...
It has also been noted that glycine transport is inhibited by a protonophore, FCCP, or valinomycin plus nigericin, indicating ...
Valinomycin, Nonactin, Ionomycin Special antibiotics and molecular biology reagents. Anisomycin, Thiolutin, Wortmannin, K252a, ...
Dactinomycin Daptomycin Gramicidin S Hymenistatin Microcystins Nisin Nodularin Octreotide Polymyxin B Pristinamycin Valinomycin ...
... similar to valinomycin produced by Streptomyces griseus) produced by nonribosomal peptide synthesis. Cereulide is believed to ...
Family 2.B.1 The Valinomycin Carrier Family 2.B.2 The Monensin Family 2.B.3 The Nigericin Family 2.B.4 The Macrotetrolide ...
Tetraphenylphosphonium chloride Valinomycin Arsenate Uncoupling protein Not to be confused with the recreation drug, ...
C5H4N4O3 Uridine Valine Valinomycin Vanabins Vasopressin Verruculogen Vitamins (in general) Vitamin A (retinol) Vitamin B () ...
Valinomycin is a naturally occurring dodecadepsipeptide used in the transport of potassium and as an antibiotic. Valinomycin is ... Valinomycin from Fermentek. Valinomycin in the Pesticide Properties DataBase (PPDB). ... Valinomycin is a dodecadepsipeptide, that is, it is made of twelve alternating amino acids and esters to form a macrocyclic ... Valinomycin is highly selective for potassium ions over sodium ions within the cell membrane. It functions as a potassium- ...
From Merck Index, 11th ed) Valinomycin is a potassium selective ionophore and is commonly used as a tool in biochemical studies ... Valinomycin. Accession Number. DB14057. Type. Small Molecule. Groups. Experimental. Description. A cyclododecadepsipeptide ... From Merck Index, 11th ed) Valinomycin is a potassium selective ionophore and is commonly used as a tool in biochemical studies ... The therapeutic efficacy of Adenovirus type 7 vaccine live can be decreased when used in combination with Valinomycin. ...
Valinomycin, is used as a potassium ionophore shown to induce cell death. Due to the ion-selective nature of valinomycin, it is ... Valinomycin-induced apoptosis in Chinese hamster ovary cells. Neurosci. Lett. 2006, 405( 1-2), 68-73. ...
Valinomycins molecular structure efficiently surrounds the K+ ion, as this structure has to exactly correspond to the K+ ion ... It is obtained that capturing a К+(Na+) ion in the valinomycin cavity is not possible for all values of the electric field ... Each of the two kinds of ions (К+ or Na+) has its own critical electric field associated with ion binding to valinomycin, for ... An analysis has been performed of the interaction processes for the system of valinomycin + К+(Na+) ion in water solvent. ...
Cereulide and valinomycin are highly similar cyclic dodecadepsipeptides with potassium ionophoric properties. Cereulide, ... A comparative analysis of the antimicrobial activity of valinomycin produced by Streptomyces spp. and cereulide was performed ... Comparative analysis of antimicrobial activities of valinomycin and cereulide, the Bacillus cereus emetic toxin. ...
"Valinomycin" is a descriptor in the National Library of Medicines controlled vocabulary thesaurus, MeSH (Medical Subject ... From Merck Index, 11th ed) Valinomycin is a potassium selective ionophore and is commonly used as a tool in biochemical studies ... This graph shows the total number of publications written about "Valinomycin" by people in this website by year, and whether " ... Below are the most recent publications written about "Valinomycin" by people in Profiles. ...
Differential Permeabilization Effects of Ca2+ and Valinomycin on the Inner and Outer Mitochondrial Membranes as Revealed by ... Differential Permeabilization Effects of Ca2+ and Valinomycin on the Inner and Outer Mitochondrial Membranes as Revealed by ... Differential Permeabilization Effects of Ca2+ and Valinomycin on the Inner and Outer Mitochondrial Membranes as Revealed by ... Differential Permeabilization Effects of Ca2+ and Valinomycin on the Inner and Outer Mitochondrial Membranes as Revealed by ...
Valinomycin is obtained from the cells of several Streptomyces strains, among which S. tsusimaensis and S. fulvissimus. ... Valinomycin is a potent antibiotic which acts as a potassium (K+) ionophore. Induces K+ conductivity in cell membranes. Also ... In the presence of valinomycin, K+ is freely permeable. Valinomycin at AG Scientific, Inc.. Bulk and custom orders available. ... "Valinomycin." Valinomycin - an Overview , ScienceDirect Topics, 2016, www.sciencedirect.com/topics/biochemistry-genetics-and- ...
The Effect of Valinomycin on Potassium and Sodium Permeability of HK and LK Sheep Red Cells. Daniel C. Tosteson, P. Cook, ... The Effect of Valinomycin on Potassium and Sodium Permeability of HK and LK Sheep Red Cells ... A cyclic depsipeptide antibiotic, valinomycin, was found to produce increased selective permeability of the plasma membranes of ...
Valinomycin. The macrocycle valinomycin, isolated from an Actinomycete culture, is a known potassium anionophore [96]. ... Valinomycin is also a signal peptide-specific inhibitor of hamster prion protein (PrP) translocation [98]. Inefficient ... Ryoo IJ, Park HR, Choo SJ, Hwang JH, Park YM, Bae KH, Shin-Ya K, Yoo ID (2006) Selective cytotoxic activity of valinomycin ... Reduced BiP levels in valinomycin-treated cancer cells can thus result in cell death under ER stress conditions, which are ...
Sankaram, MB and Easwaran, KRK (1984) Location of valinomycin in lipid vesicles. In: Journal of Biosciences, 6 (5). pp. 635-642 ... The results show that valinomycin is located near the head group region of dipalmitoyl phosphatidyl choline vesicles and in the ... The location of the cyclododecadepsipeptide, valinomycin in vesicles formed from two synthetic lipids is studied by ... Valinomycin;dipalmitoylphosphatidylcholine;dimyristoylphosphatidylcholine;differential scanning calorimetry;electron spin ...
Nonprotonophoric electrogenic Cl− transport mediated by valinomycin-like carriers. Xin Wu, Luke Judd, Ethan N.W. Howe, Anne M. ... Nonprotonophoric electrogenic Cl− transport mediated by valinomycin-like carriers. / Wu, Xin; Judd, Luke; Howe, Ethan N.W. ; ... Our study demonstrates for the first time that a valinomycin equivalent for Cl− -selective transport is achievable. ... Fingerprint Dive into the research topics of Nonprotonophoric electrogenic Cl− transport mediated by valinomycin-like carriers ...
Ozdemir, A and Lednev, IK and Asher, SA (2005) UVRR spectroscopic studies of valinomycin complex formation in different ... We investigated the complexation of valinomycin (VM) in different solvent environments with the aid of the UVRR spectroscopy. ...
Valinomycin Crystal Structure Determination by Direct Methods. By W. L. Duax, H. Hauptman, C. M. Weeks, D. A. Norton ...
Valinomycin Cayman Chemical. A cyclododecadepsipeptide potassium-selective ionophore antibotic; induces apoptosis in several ...
Valinomycin. b. 1,000. 1,000/10,000 2032-65-7. Methiocarb. 10. 500/10,000 ...
PK, proteinase K; Val, valinomycin; p, precursor protein; m, mature protein; CM, crude mitochondria; BPM, bead-purified ...
36 nM valinomycin; and 1-100 mM KCl. After measurement of the ATP synthesis reactions, the pH of the mixtures (ΔpHout) was ... concentrations to the outside of the proteoliposomes in the presence of 36 nM valinomycin. The ΔΨ was calculated from the ...
Valinomycin. 0.64 ± 0.26. 0.43 ± 0.20. Antimucin. 0.64 ± 0.38. 4.23 ± 2.30 Picropodophyllin. 0.75 ± 0.33. 1.02 ± 0.54. ...
ROS production exhibited a biphasic dependence on valinomycin concentration, with peak production occurring at valinomycin ... ROS production decreased with higher concentrations of valinomycin and with all concentrations of a classical protonophoretic ...
... valinomycin, was found to produce increased selective permeability of the plasma membranes of HK and LK sheep red blood cells ... The effect of valinomycin on potassium and sodium permeability of HK and LK sheep red cells. ... The effect of valinomycin on potassium and sodium permeability of HK and LK sheep red cells. ... A cyclic depsipeptide antibiotic, valinomycin, was found to produce increased selective permeability of the plasma membranes of ...
The incubation with valinomycin for 10 min. at 37 degrees C in a low K+ medium provoked a marked and dose-dependent reduction ... we have studied by flow cytometry the changes in membrane potential provoked by the K+ ionophor valinomycin, a drug known to ...
The maintenance of ion gradients across the plasma membrane by the Na(+)-K(+)-ATPase has been shown to utilize a large fraction of the total cellular energy demand. In view of the importance of ion gradients to cellular function, and the remarkable anoxia tolerance of Chrysemys picta bellii (western …
... valinomycin, and Ca2+ indicate that these mitochondria behave similarly to vertebrate mitochondria regarding the properties of ...
Alternatively valinomycin may be incorporated into the membrane by injection of a dilute solution of valinomycin in ethanol ... Addition of valinomycin to the glycerol monooleate in decane solution (100 mg/ml, 3000:1 glycerol monooleate:valinomycin) ... Immobilized valinomycin molecule for K+ sensor. US5204239 *. Jan 9, 1991. Apr 20, 1993. Yeda Research And Development Co., Ltd. ... Details of valinomycin tests for reservoir efficiency. A test was devised for determining the relative reservoir ability of the ...
The higher valinomycin yield was likely the result of redistribution of the metabolic flux from bafilomycin to valinomycin ... The higher valinomycin yield was likely the result of redistribution of the metabolic flux from bafilomycin to valinomycin ... The higher valinomycin yield was likely the result of redistribution of the metabolic flux from bafilomycin to valinomycin ... The higher valinomycin yield was likely the result of redistribution of the metabolic flux from bafilomycin to valinomycin ...
Anion effects on valinomycin-cation complexes". Journal of the American Chemical Society. 104 (15): 4085-4091. doi:10.1021/ ... An example of a carrier ionophore is valinomycin, a molecule that transports a single potassium cation. Carrier ionophores may ... Thompson, Michael; Krull, U.J. (September 1982). "The electroanalytical response of the bilayer lipid membrane to valinomycin: ... Steinrauf, L. K.; Hamilton, J. A.; Sabesan, M. N. (1982). "Crystal structure of valinomycin-sodium picrate. ...
The potassium electrode consists of valinomycin membrane. The voltage (potential) change that takes place within the membrane ...
The potassium electrode consists of valinomycin membrane. The voltage (potential) change that takes place within the membrane ...
No effect was observed upon omission of valinomycin or dilution of vesicles loaded with KPi into equimolar KPi in the presence ... RSO membrane vesicles expressing WT LacY prepared in KPi (for efflux without an imposed ΔΨ) or NaPi and valinomycin (for efflux ... After 3-h equilibration with 10 mM [14C]lactose (5 mCi/mmol) in the presence of 25 μM valinomycin (dissolved in 0.5% DMSO final ... Rapid dilution of RSO membrane vesicles preloaded with NaPi into equimolar KPi in the presence of valinomycin generates a ...
  • Valinomycin is a naturally occurring dodecadepsipeptide used in the transport of potassium and as an antibiotic. (wikipedia.org)
  • A cyclic depsipeptide antibiotic, valinomycin, was found to produce increased selective permeability of the plasma membranes of HK and LK sheep red blood cells to potassium but not to sodium ions. (rupress.org)
  • The term ionophore (from Greek ion carrier or ion bearer) was proposed by Berton Pressman in 1967 when he and his colleagues were investigating the antibiotic mechanisms of valinomycin and nigericin. (wikipedia.org)
  • Many Streptomyces strains are known to produce valinomycin (VLM) antibiotic and the VLM biosynthetic gene cluster (vlm) has been characterized in two independent isolates. (jove.com)
  • The use of cereulide standard was also compared to the most frequently used surrogate standard, the antibiotic valinomycin. (mdpi.com)
  • AG Scientific is a leading supplier of high-quality ionophores, such as Valinomycin to the in vitro diagnostic (IVD) and medical device industries. (agscientific.com)
  • Reaction is unaffected by the ionophores valinomycin, valinomycin plus nigericin, and carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP). (uniprot.org)
  • Ionophores such as nonactin and valinomycin also display a marked preference for the potassium cation over other cations. (newworldencyclopedia.org)
  • Potassium ionophore valinomycin triggers an increase of the cytoplasinic calcium concentration. (nii.ac.jp)
  • by addition of a K+ ionophore (valinomycin), but the combination of permeant anions and valinomycin appeared to cause rapid dissipation of driving forces. (uio.no)
  • The linear rates of GSH efflux from primary cultured RCEC were determined in cells maintained in NaCl-buffer (135 mM NaCl), choline chloride-buffer (135 mM choline-Cl - ), high K + buffer (135 mM KCl and 5 mM NaCl) with or without 1 µM potassium ionophore valinomycin, and NaCl-buffer with 1 µM valinomycin. (arvojournals.org)
  • This difference is important for maintaining the selectivity of valinomycin for the transport of potassium ions (and not sodium ions) in biological systems. (wikipedia.org)
  • Ionic selectivity of valinomycin in the dipalmitoylphosphatidylcholine monolayers. (mpg.de)
  • ROS production decreased with higher concentrations of valinomycin and with all concentrations of a classical protonophoretic uncoupler. (mendeley.com)
  • In the present study, K+ channel activity was mimicked by picomolar concentrations of valinomycin. (lu.se)
  • Valinomycin is obtained from the cells of several Streptomyces species, S. fulvissimus being a notable one. (wikipedia.org)
  • A comparative analysis of the antimicrobial activity of valinomycin produced by Streptomyces spp. (wur.nl)
  • Increased valinomycin production in mutants of Streptomyces sp. (elsevier.com)
  • Fingerprint Dive into the research topics of 'Increased valinomycin production in mutants of Streptomyces sp. (elsevier.com)
  • Valinomycin-induced apoptosis in Chinese hamster ovary cells. (alfa.com)
  • Publications] M. Takeda: 'Induction of apoptosis by valinomycin in mouse taste buds'日本解剖学会東北北海道連合地方会. (nii.ac.jp)
  • In two human cell lines (K562 and U937), we have studied by flow cytometry the changes in membrane potential provoked by the K+ ionophor valinomycin, a drug known to affect mitochondrial membrane potential, while the K+/H+ ionophor nigericin, known to affect intracellular pH but not mitochondrial membrane potential, was used as control. (nih.gov)
  • Valinomycin is a dodecadepsipeptide, that is, it is made of twelve alternating amino acids and esters to form a macrocyclic molecule. (wikipedia.org)
  • The structure of valinomycin has twelve alternating amino acids and esters that are essential for the binding of metal ions, and also for solvation in the polar solvent. (agscientific.com)
  • Cereulide and valinomycin are highly similar cyclic dodecadepsipeptides with potassium ionophoric properties. (wur.nl)
  • The permeabilization of Trypanosoma brucei procyclic and bloodstream trypomastigotes with digitonin permitted the quantitative estimation of a mitochondrial membrane potential of the order of 130-140 mV, in both forms, using safranine O. Dependence on substrate oxidation and response of the procyclic mitochondrial membrane potential to phosphate, FCCP, valinomycin, and Ca2+ indicate that these mitochondria behave similarly to vertebrate mitochondria regarding the properties of their electrochemical proton gradient. (nih.gov)
  • To examine the effect of bafilomycin biosynthesis on valinomycin production, the bafilomycin biosynthetic gene cluster was cloned from the genome of strain M10, as were two branched-chain α-keto acid dehydrogenase (BCDH) gene clusters related to precursor supply for bafilomycin biosynthesis. (elsevier.com)
  • Valinomycin is highly selective for potassium ions over sodium ions within the cell membrane. (wikipedia.org)
  • The aim of this work is to estimate the value of the electric field (potentials) for the system of valinomycin + К+ and Na+ ions based on a molecular dynamics (MD) study. (scirp.org)
  • Each of the two kinds of ions (К+ or Na+) has its own critical electric field associated with ion binding to valinomycin, for which to exist, the ion has to remain localized inside the valinomycin cavity. (scirp.org)
  • Forester, T.R., Smith, W. and Clarke, J.H.R. (1995) Capture of potassium ions by valinomycin: A molecular dynamics simulation study. (scirp.org)
  • K+ ions bind to valinomycin and echangeges across the membrane. (agscientific.com)
  • An example of a carrier ionophore is valinomycin, a molecule that transports a single potassium cation. (wikipedia.org)
  • Matrix pH was manipulated by inorganic phosphate, nigericine, and low concentrations of uncoupler or valinomycin.In the absence of inorganic phosphate, when the matrix was the most alkaline, pH shift in the medium above 7 induced permeability transition accompanied by the decrease of ROS production.The phenomena revealed in this report are important for understanding mechanisms governing mitochondrial production of reactive oxygen species, in particular that related with uncoupling proteins. (nih.gov)
  • Matrix pH was manipulated by inorganic phosphate, nigericine, and low concentrations of uncoupler or valinomycin. (nih.gov)
  • They dissipate the valinomycin-induced membrane potential in liposomes. (tcdb.org)
  • The location of the cyclododecadepsipeptide, valinomycin in vesicles formed from two synthetic lipids is studied by differential scanning calorimetry, spin-label partitioning electron paramagnetic resonance and $[^1H]$-nuclear magnetic resonance. (iisc.ac.in)
  • During studies to increase the yield of valinomycin (a cyclododecadepsipeptide) in strain M10, additional antifungal metabolites, including bafilomycin derivatives (macrolide antibiotics), were identified. (elsevier.com)
  • Valinomycin acts as a nonmetallic isoforming agent in potassium selective electrodes. (wikipedia.org)
  • From Merck Index, 11th ed) Valinomycin is a potassium selective ionophore and is commonly used as a tool in biochemical studies. (drugbank.ca)
  • Due to the ion-selective nature of valinomycin, it is used in ion-selective electrodes. (alfa.com)
  • Our study demonstrates for the first time that a valinomycin equivalent for Cl− -selective transport is achievable. (bris.ac.uk)
  • In the absence of a K+ specific ionophore like valinomycin, K+ solely seldom crosses a lipid bilayer. (agscientific.com)
  • Lowering the osmolarity of the buffer induced an increase in mitochondrial volume and improved CRC similar to valinomycin without inducing uncoupling or otherwise affecting respiration. (lu.se)
  • For polar solvents, valinomycin will mainly expose the carbonyls to the solvent and in nonpolar solvents the isopropyl groups are located predominantly on the exterior of the molecule. (wikipedia.org)
  • Marrone, T.J. and Kenneth, M.M., Jr. (1995) Molecular Recognition of K+ and Na+ by valinomycin in methanol. (scirp.org)
  • The incubation with valinomycin for 10 min. (nih.gov)
  • However, hyperpolarizing cell membranes with 1 µM valinomycin in the NaCl incubation buffer stimulated efflux rates more than two-fold into apical fluid. (arvojournals.org)
  • The serum concentration of Valinomycin can be increased when it is combined with Abemaciclib. (drugbank.ca)
  • ROS production exhibited a biphasic dependence on valinomycin concentration, with peak production occurring at valinomycin concentrations that catalyze about the same K(+) influx as K(ATP) channel openers. (mendeley.com)
  • Valinomycin-based ionselective electrodes display selectivity factors of 50 to 100 for [K.sup. (thefreelibrary.com)
  • Net guanidine transport measured at 0.1 mM across the conjunctiva was decreased by 71% or 82%, respectively, on the addition of 1 μM valinomycin (a K + ionophore) in both bathing fluids or in a high K + buffer in the mucosal fluid. (arvojournals.org)
  • The stability constant K for the potassium-valinomycin complex is nearly 100,000 times larger than that of the sodium-valinomycin complex. (wikipedia.org)
  • A valinomycin calibration curve demonstrates this approach can robustly report membrane potentials over at least an ∼144-mV range with an accuracy of ∼12 mV. (asm.org)
  • Eisenman, G. and Alvarez, O. (1992) Ionic selectivity of proteins: Lessons from molecular dynamics simulations on valinomycin. (scirp.org)
  • All chemicals of analytical grade, valinomycin, 3-3' diethylthiadicarbocyanine iodide (DiS-C2 (5)) and Wistar rats were purchased from the commercial source. (ispub.com)
  • Valinomycin, is used as a potassium ionophore shown to induce cell death. (alfa.com)
  • Effect of aqueous subphase exchange on the monolayer characteristics of valinomycin. (mpg.de)
  • The putative mitoKATP channel opener diazoxide did not mimic the effect of valinomycin. (lu.se)
  • The beneficial effect of valinomycin on CRC was not mediated by H2O2-induced PKCepsilon activation. (lu.se)
  • Valinomycin did not affect the high K + effect. (arvojournals.org)
  • Pinkerton M, Steinrauf LK, Dawkins P: The molecular structure and some transport properties of valinomycin. (drugbank.ca)
  • An analysis has been performed of the interaction processes for the system of valinomycin + К+(Na+) ion in water solvent. (scirp.org)
  • In the presence of valinomycin, K+ is freely permeable. (agscientific.com)
  • Monolayer characteristics of valinomycin in the presence of various salts in aqueous subphase. (mpg.de)
  • The results obtained for the electrical potential reveal a stronger valinomycin binding-especially with the potassium ion. (scirp.org)
  • The results show that valinomycin is located near the head group region of dipalmitoyl phosphatidyl choline vesicles and in the hydrophobic core of the dimyristoyl phosphatidyl choline vesicles in the liquid crystalline phase. (iisc.ac.in)
  • In another null mutant (M10bkdFm) of a gene encoding a subunit of the BCDH complex (bkdF), bafilomycin production was completely abolished and valinomycin production increased fourfold relative to that in the wild-type M10 strain. (elsevier.com)
  • Eisenman, G., Aqvist, J. and Alvarez, O. (1991) Free energies underlying ion binding and transport in protein channels: Free energy perturbation simulations of ion binding and selectivity for valinomycin. (scirp.org)
  • Nevertheless, using several liposome membrane-based assays, we identify two newly-developed small molecules that promote electrogenic Cl− transport without effectively dissipating the transmembrane pH gradient, essentially mimicking the electrogenic cationophore valinomycin. (bris.ac.uk)
  • A null mutant (M10bafm) of one bafilomycin biosynthetic gene (bafV) failed to produce bafilomycin, but resulted in a 1.2- to 1.5-fold increase in the amount of valinomycin produced. (elsevier.com)
  • Valinomycin was recently reported to be the most potent agent against severe acute respiratory-syndrome coronavirus (SARS-CoV) in infected Vero E6 cells. (wikipedia.org)
  • The higher valinomycin yield was likely the result of redistribution of the metabolic flux from bafilomycin to valinomycin biosynthesis, because the two antibiotics share a common precursor, 2-ketoisovaleric acid, a deamination product of valine. (elsevier.com)
  • 20 and 24 h after injection of valinomycin, positive nuclei were scattered in the taste buds. (nii.ac.jp)
  • The therapeutic efficacy of Adenovirus type 7 vaccine live can be decreased when used in combination with Valinomycin. (drugbank.ca)
  • This graph shows the total number of publications written about "Valinomycin" by people in this website by year, and whether "Valinomycin" was a major or minor topic of these publications. (umassmed.edu)