Telavancin, a multifunctional lipoglycopeptide, disrupts both cell wall synthesis and cell membrane integrity in methicillin-resistant Staphylococcus aureus.
AuthorsHiggins DL, Chang R, Debabov DV, Leung J, Wu T, Krause KM, Sandvik E, Hubbard JM, Kaniga K, Schmidt DE, Gao Q, Cass RT, Karr DE, Benton BM, Humphrey PP
JournalAntimicrob Agents Chemother
PubMed ID15728913
'The emergence and spread of multidrug-resistant gram-positive bacteria represent a serious clinical problem. Telavancin is a novel lipoglycopeptide antibiotic that possesses rapid in vitro bactericidal activity against a broad spectrum of clinically relevant gram-positive pathogens. Here we demonstrate that telavancin''s antibacterial activity derives from at least two mechanisms. As observed ... More
Preparation of giant liposomes in physiological conditions and their characterization under an optical microscope.
AuthorsAkashi K, Miyata H, Itoh H, Kinosita K
JournalBiophys J
PubMed ID8968594
'Unilamellar liposomes with diameters of 25-100 microns were prepared in various physiological salt solutions, e.g., 100 mM KCl plus 1 mM CaCl2. Successful preparation of the giant liposomes at high ionic strengths required the inclusion of 10-20% of a charged lipid, such as phosphatidylglycerol, phosphatidylserine, phosphatidic acid, or cardiolipin, in ... More
State-dependent inhibition of the mitochondrial KATP channel by glyburide and 5-hydroxydecanoate.
AuthorsJaburek M, Yarov-Yarovoy V, Paucek P, Garlid KD
JournalJ Biol Chem
PubMed ID9593694
'The mitochondrial KATP channel (mitoKATP) is hypothesized to be the receptor for the cardioprotective effects of K+ channel openers (KCO) and for the blocking of cardioprotection by glyburide and 5-hydroxydecanoate (5-HD). Studies on glyburide have indicated that this drug is inactive in isolated mitochondria. No studies of the effects of ... More
Alkylsulfonates as probes of uncoupling protein transport mechanism. Ion pair transport demonstrates that direct H(+) translocation by UCP1 is not necessary for uncoupling.
AuthorsJaburek M, Varecha M, Jezek P, Garlid KD
JournalJ Biol Chem
PubMed ID11468281
'The mechanism of fatty acid-dependent uncoupling by mitochondrial uncoupling proteins (UCP) is still in debate. We have hypothesized that the anionic fatty acid head group is translocated by UCP, and the proton is transported electroneutrally in the bilayer by flip-flop of the protonated fatty acid. Alkylsulfonates are useful as probes ... More
Phospholipid subclass-specific alterations in the kinetics of ion transport across biologic membranes.
AuthorsChen X, Gross RW
JournalBiochemistry
PubMed ID7947788
'Although the predominance of plasmalogens in electrically-active membranes (e.g., sarcolemma) is well-known, identification of the molecular mechanisms through which the vinyl ether linkage facilitates electrophysiologic function has remained elusive. Herein we demonstrate that the kinetics of both carrier-mediated (i.e., valinomycin) and passive ion transport are substantially different in membranes comprised ... More
The effect of mechanical deformation on the distribution of ions in fibroblasts.
AuthorsLeeves MA, McDonald F
JournalAm J Orthod Dentofacial Orthop
PubMed ID7771368
'The extracellular and intracellular sodium, potassium and chloride concentrations were determined in fibroblast cells located in the rat calvarium. The ionic values were determined by fluorescence microscopy after incubation with the fluorescent probes, sodium-binding benzofuran isophthalate (SBFI), potassium-binding benzofuran isophthalate (PBFI) and 6-methoxy-N-(3-sulfopropyl) quinolinium (SPQ) (Dyes were supplied by CALBIOCHEM, ... More
Acute gentamicin ototoxicity in cochlear outer hair cells of the guinea pig.
AuthorsErnst A, Reuter G, Zimmermann U, Zenner HP
JournalBrain Res
PubMed ID8156402
'The acute effects of the aminoglycoside antibiotics gentamicin on isolated cochlear outer hair cells (OHC) was investigated by whole-cell patch-clamp and measurements of the intracellular potassium level by means of the potassium-sensitive dye PBFI. In addition, the accompanying length changes of OHC are described. It could be shown that gentamicin ... More
A structure-activity study of fatty acid interaction with mitochondrial uncoupling protein.
AuthorsJezek P, Modrianský M, Garlid KD
JournalFEBS Lett
PubMed ID9187360
Fatty acid (FA) uniport via mitochondrial uncoupling protein (UcP) was detected fluorometrically with PBFI, potassium-binding benzofuran phthalate and SPQ, 6-methoxy-N-(3-sulfopropyl)-quinolinium, indicating K+ and H+, respectively. The FA structural patterns required for FA flip-flop, UcP-mediated FA uniport, activation of UcP-mediated H+ transport in proteoliposomes, and inhibition of UcP-mediated Cl- uniport by ... More
Potential misevaluation of the ground-state dissociation constant from fluorimetric titrations: application to the ion indicators SBFI, PBFI, and fura-2.
AuthorsKowalczyk A, Boens N, Meuwis K, Ameloot M
JournalAnal Biochem
PubMed ID9025965
A test based on time-resolved fluorescence experiments is proposed to assess the interference of an excited-state reaction with the fluorimetric determination of the ground-state dissociation constant Kd of ion [symbol: see text] fluorescent indicator complexes. If an inflection point occurs in the plot of the fluorescence signal vs -log [ion] ... More
Visual imaging of ion distribution in human epidermis.
AuthorsDenda M, Hosoi J, Asida Y
JournalBiochem Biophys Res Commun
PubMed ID10872816
The distribution of calcium, magnesium, potassium, sodium, and hydrogen ions in the human epidermis was visualized by blotting to gel containing chemical indicators and the effects of skin barrier disruption were examined. In normal skin, both calcium and magnesium were localized with high concentration in the upper epidermis. EDTA blocked ... More
Identification and properties of a novel intracellular (mitochondrial) ATP-sensitive potassium channel in brain.
AuthorsBajgar R, Seetharaman S, Kowaltowski AJ, Garlid KD, Paucek P
JournalJ Biol Chem
PubMed ID11441006
Protection of heart against ischemia-reperfusion injury by ischemic preconditioning and K(ATP) channel openers is known to involve the mitochondrial ATP-sensitive K(+) channel (mitoK(ATP)). Brain is also protected by ischemic preconditioning and K(ATP) channel openers, and it has been suggested that mitoK(ATP) may also play a key role in brain protection. ... More
Porcine iris pigment epithelial cells can take up retinal outer segments.
AuthorsSchraermeyer U, Enzmann V, Kohen L, Addicks K, Wiedemann P, Heimann K
JournalExp Eye Res
PubMed ID9268596
This study investigates the ability of iris epithelial cells (IPE) to ingest rod outer segments (ROS) and compares the amount of phagocytosis of porcine RPE and IPE cells by the use of a pH sensitive fluorescent dye (carboxy SNAFL) at the light microscopic level. The dye allowed investigation of ingestion ... More
Photophysics of the fluorescent K+ indicator PBFI.
AuthorsMeuwis K, Boens N, De Schryver FC, Gallay J, Vincent M
JournalBiophys J
PubMed ID7647249
The fluorescent indicator PBFI is widely used for the determination of intracellular concentrations of K+. To investigate the binding reaction of K+ to PBFI in the ground and excited states, steady-state and time-resolved measurements were performed. The fluorescence decay surface was analyzed with global compartmental analysis yielding the following values ... More
Ionic permeabilities induced by Bacillus thuringiensis in Sf9 cells.
AuthorsVachon V, Paradis MJ, Marsolais M, Schwartz JL, Laprade R
JournalJ Membr Biol
PubMed ID8558602
The effect of Bacillus thuringiensis insecticidal toxins on the monovalent cation content and intracellular pH (pHi) of individual Sf9 cells of the lepidopteran species Spodoptera frugiperda (fall armyworm) was monitored with the fluorescent indicators potassium-binding benzofuran isophthalate (PBFI) and 2',7'-bis(carboxyethyl)-5,6-carboxyfluorescein (BCECF). The sequential removal of K+ and Na+ from the ... More
Quantitative measurement of cationic fluxes, selectivity and membrane potential using liposomes multilabelled with fluorescent probes.
AuthorsVenema K, Gibrat R, Grouzis JP, Grignon C
JournalBiochim Biophys Acta
PubMed ID8382957
Liposomes of egg PC/PG (8:2, mol/mol) were multilabelled with PBFI, pyranine and oxonol VI, fluorescent probes for, respectively, K+, H+ and membrane potential. Monitoring fluorescence with a multichannel photoncounting spectrofluorometer during K+ filling experiments allowed to measure K+ influx, the associated H+ efflux and the membrane potential, continuously and simultaneously. ... More
Purification of a reconstitutively active K+/H+ antiporter from rat liver mitochondria.
We describe purification of three different states of the 82-kDa K+/H+ antiporter from rat liver mitochondria. The denatured 82-kDa protein, identified by its selective labeling with [14C]dicyclohexylcarbodiimide (DCCD), was purified by preparative two-dimensional gel electrophoresis. This purified product was used to raise and immunopurify monospecific polyclonal antibodies. Western blot analysis ... More
On the mechanism of mitochondrial uncoupling protein 1 function.
AuthorsBreen EP, Gouin SG, Murphy AF, Haines LR, Jackson AM, Pearson TW, Murphy PV, Porter RK
JournalJ Biol Chem
PubMed ID16291746
Native uncoupling protein 1 (UCP 1) was purified from rat mitochondria by hydroxyapatite chromatography and identified by peptide mass mapping and tandem mass spectrometry. Native and expressed UCP 1 were reconstituted into liposomes, and proton flux through UCP 1 was shown to be fatty acid-dependent and GDP-sensitive. To investigate the ... More
Reconstitution and partial purification of the glibenclamide-sensitive, ATP-dependent K+ channel from rat liver and beef heart mitochondria.
The transport properties of mitochondria are such that net potassium flux across the inner membrane determines mitochondrial volume. It has been known that K+ uptake is mediated by diffusive leak driven by the high electrical membrane potential maintained by redox-driven, electrogenic proton ejection and that regulated K+ efflux is mediated ... More
The plant inorganic pyrophosphatase does not transport K+ in vacuole membrane vesicles multilabeled with fluorescent probes for H+, K+, and membrane potential.
AuthorsRos R, Romieu C, Gibrat R, Grignon C
JournalJ Biol Chem
PubMed ID7876200
It has been claimed that the inorganic pyrophosphatase (PPase) of the plant vacuolar membrane transports K+ in addition to H+ in intact vacuoles (Davies, J. M., Poole, R. J., Rea, P. A., and Sanders, D. (1992) Proc. Natl. Acad. Sci. U.S.A. 89, 11701-11705). Since this was not confirmed using the ... More
The mitochondrial KATP channel as a receptor for potassium channel openers.
AuthorsGarlid KD, Paucek P, Yarov-Yarovoy V, Sun X, Schindler PA
JournalJ Biol Chem
PubMed ID8621517
The biochemical properties of the mitochondrial KATP channel are very similar to those of plasma membrane KATP channels, including inhibition by low concentrations of ATP and glyburide (Paucek, P., Mironova, G., Mahdi, F., Beavis, A. D., Woldegiorgis, G., and Garlid, K. D. (1992) J. Biol. Chem. 267, 26062-26069). Plasma membrane ... More
In the previous sections we demonstrated imaging of intracellular Ca2+ using our approach to FLIM. What other analytes can be imaged using FLIM? We have now characterized the lifetime of a good number of ion indicators. Based on these studies we know that Cl- can be imaged using FLIM with ... More
Lactate transport in mammalian ventricle. General properties and relation to K+ fluxes.
AuthorsShieh RC, Goldhaber JI, Stuart JS, Weiss JN
JournalCirc Res
PubMed ID8156630
Net cellular L-lactate efflux associated with accelerated anaerobic glycolysis has been implicated as a potential cause of the marked cellular K+ loss contributing to lethal cardiac arrhythmias in ischemic heart and to impaired function of fatigued skeletal muscle. To examine the mechanisms of transsarcolemmal L-lactate movement in the heart, isolated ... More
Sensing of electrolytes in urine using a miniaturized paper-based device.