Protonation dynamics of the extracellular and cytoplasmic surface of bacteriorhodopsin in the purple membrane.
AuthorsNachliel E,Gutman M,Kiryati S,Dencher NA
JournalProceedings of the National Academy of Sciences of the United States of America
PubMed ID8855251
The dynamics of proton binding to the extracellular and the cytoplasmic surfaces of the purple membrane were measured by laser-induced proton pulses. Purple membranes, selectively labeled by fluorescein at Lys-129 of bacteriorhodopsin, were pulsed by protons released in the aqueous bulk from excited pyranine (8-hydroxy-1,3,6-pyrenetrisulfonate) and the reaction of protons ... More
An improved procedure for reconstitution of the uncoupling protein and in-depth analysis of H+/OH- transport.
AuthorsWinkler E,Klingenberg M
JournalEuropean journal of biochemistry
PubMed ID1378400
An improved procedure for reincorporation of isolated uncoupling protein (UCP) from brown adipose tissue into phospholipid vesicles is reported and H+ uptake in K(+)-driven exchange diffusion quantitatively analyzed. UCP is isolated and reconstituted with medium-length linear-chain alkyl polyoxyethylene. In the critical step of vesicle formation, the stepwise removal of the ... More
Fluorescent indicators of ion concentrations.
AuthorsTsien RY
JournalMethods Cell Biol
PubMed ID2538708
Elicitor stimulation of the defense response in cultured plant cells monitored by fluorescent dyes.
AuthorsLow PS, Heinstein PF
JournalArch Biochem Biophys
PubMed ID3753013
Addition of fungal elicitors to plant cells in suspension is known to stimulate biochemical changes in the plant cell leading to production of defense compounds. In this paper we demonstrate that introduction of elicitors from the pathogenic fungus Verticillium dahliae to cultured cotton, tobacco, or soybean cells leads to a ... More
Ligand binding and release of an analogue of 2,3-diphosphoglycerate from human hemoglobin.
AuthorsMacQuarrie R, Gibson QH
JournalJ Biol Chem
PubMed ID5057081
Effect of sialyl Lewis X-glycoliposomes on the inhibition of E-selectin-mediated tumour cell adhesion in vitro.
AuthorsZeisig R, Stahn R, Wenzel K, Behrens D, Fichtner I
JournalBiochim Biophys Acta
PubMed ID14757218
'The aim of this study was to evaluate the potential of different types of sialyl Lewis X-conjugated liposomes as competitive inhibitors for tumour cell adhesion to endothelial E-selectin. Sterically stabilised liposomes with the sLeX ligand at the terminal end of the polyethyleneglycol (PEG) chain, as well as vesicles that had ... More
Arginine-82 regulates the pKa of the group responsible for the light-driven proton release in bacteriorhodopsin.
'In wild-type bacteriorhodopsin light-induced proton release occurs before uptake at neutral pH. In contrast, in mutants in which R82 is replaced by a neutral residue (as in R82A and R82Q), only a small fraction of the protons is released before proton uptake at neutral pH; the major fraction is released ... More
Receptor for anionic pyrene derivatives provides the basis for new biomembrane assays.
AuthorsWinschel CA, Kalidindi A, Zgani I, Magruder JL, Sidorov V
JournalJ Am Chem Soc
PubMed ID16231924
'This study describes a new receptor cyclen 1 capable of strong selective binding of pyrene-based anionic dyes under near-physiological conditions. This receptor comprises four naphthylthiourea groups tethered to a cyclen core via an ester linkage. The complexation behavior of cyclen 1 receptor is characterized by a series of (1)H NMR, ... More
Proton dissociation dynamics in the aqueous layer of multilamellar phospholipid vesicles.
AuthorsRochel S, Nachliel E, Huppert D, Gutman M
JournalJ Membr Biol
PubMed ID1963904
'The water layers interspacing between the phospholipid membranes of a multilamellar vesicle are 3-10 water layers across and their width is adjusted by osmotic pressure (Parsegian, V.A., et al., 1986. Methods Enzymol. 127:400-416). In these thin water layers we dissolved pyranine (8 hydroxypyrene 1,3,6 trisulfonate), a compound which, upon photo ... More
Direct test of the critical exponents at the sol-gel transition.
AuthorsKaya D, Pekcan O, Yilmaz Y
JournalPhys Rev E Stat Nonlin Soft Matter Phys
PubMed ID14995677
'The steady state fluorescence technique was used to study the sol-gel transition for the solution-free radical cross-linking polymerization of acrylamide (AAm), with N,N''-methylenebis (acrylamide) as cross linker in the presence of ammonium persulfate as an initiator. Pyranine (8-hydroxypyrene-1, 3,6-trisulfonic acid, trisodium salt) is used as a fluoroprobe for monitoring the ... More
pH gradients across phospholipid membranes caused by fast flip-flop of un-ionized fatty acids.
AuthorsKamp F, Hamilton JA
JournalProc Natl Acad Sci U S A
PubMed ID1454821
'A central, unresolved question in cell physiology is how fatty acids move across cell membranes and whether protein(s) are required to facilitate transbilayer movement. We have developed a method for monitoring movement of fatty acids across protein-free model membranes (phospholipid bilayers). Pyranin, a water-soluble, pH-sensitive fluorescent molecule, was trapped inside ... More
Oxidative stress decreases pHi and Na(+)/H(+) exchange and increases excitability of solitary complex neurons from rat brain slices.
AuthorsMulkey DK, Henderson RA, Ritucci NA, Putnam RW, Dean JB
JournalAm J Physiol Cell Physiol
PubMed ID14668260
'Putative chemoreceptors in the solitary complex (SC) are sensitive to hypercapnia and oxidative stress. We tested the hypothesis that oxidative stress stimulates SC neurons by a mechanism independent of intracellular pH (pH(i)). pH(i) was measured by using ratiometric fluorescence imaging microscopy, utilizing either the pH-sensitive fluorescent dye BCECF or, during ... More
NO increases permeability of cultured human cervical epithelia by cGMP-mediated increase in G-actin.
AuthorsGorodeski GI
JournalAm J Physiol Cell Physiol
PubMed ID10794668
'Human cervical epithelial cells express mRNA for the nitric oxide (NO) synthase (NOS) isoforms ecNOS, bNOS, and iNOS and release NO into the extracellular medium. N(G)-nitro-L-arginine methyl ester (L-NAME), an NOS inhibitor, and Hb, an NO scavenger, decreased paracellular permeability; in contrast, the NO donors sodium nitroprusside (SNP) and N-(ethoxycarbonyl)-3-(4-morpholinyl)sydnonimine ... More
Regulation of intracellular pH in sea urchin eggs by medium containing both weak acid and base.
AuthorsHamaguchi MS, Watanabe K, Hamaguchi Y
JournalCell Struct Funct
PubMed ID9368712
'To establish a method of pHi regulation and to understand the pH regulation mechanism in the cell, we investigated the pHi response of unfertilized or fertilized eggs of sea urchin, applying sea water containing both weak permeant acid, acetic acid and/or base, ammonia, to eggs. Pyranine was employed as a ... More
Proton transfer dynamics on the surface of the late M state of bacteriorhodopsin.
AuthorsNachliel E, Gutman M, Tittor J, Oesterhelt D
JournalBiophys J
PubMed ID12080130
'The cytoplasmic surface of the BR (initial) state of bacteriorhodopsin is characterized by a cluster of three carboxylates that function as a proton-collecting antenna. Systematic replacement of most of the surface carboxylates indicated that the cluster is made of D104, E161, and E234 (Checover, S., Y. Marantz, E. Nachliel, M. ... More
Intracellular localization of a group II chaperonin indicates a membrane-related function.
AuthorsTrent JD, Kagawa HK, Paavola CD, McMillan RA, Howard J, Jahnke L, Lavin C, Embaye T, Henze CE
JournalProc Natl Acad Sci U S A
PubMed ID14673104
'Chaperonins are protein complexes that are believed to function as part of a protein folding system in the cytoplasm of the cell. We observed, however, that the group II chaperonins known as rosettasomes in the hyperthermophilic archaeon Sulfolobus shibatae, are not cytoplasmic but membrane associated. This association was observed in ... More
Reaction of bulk protons with a mitochondrial inner membrane preparation: time-resolved measurements and their analysis.
AuthorsGutman M, Kotlyar AB, Borovok N, Nachliel E
JournalBiochemistry
PubMed ID8384483
'The laser-induced proton pulse technique [Gutman, M. (1986) Methods Enzymol. 127, 522-538] was applied on suspensions of submitochondrial vesicles, and the exchange of protons between the bulk and the mitochondrial membranes was measured in the time-resolved domain with a submicrosecond resolution. The protons were discharged by photoexcitation of pyranine (8-hydroxypyrene-1,3,6-trisulfonate) ... More
Estrogen modulates paracellular permeability of human endothelial cells by eNOS- and iNOS-related mechanisms.
AuthorsCho MM, Ziats NP, Pal D, Utian WH, Gorodeski GI
JournalAm J Physiol
PubMed ID9950761
'Estradiol had a biphasic effect on permeability across cultures of human umbilical vein endothelial cells (HUVEC): at nanomolar concentrations it decreased the HUVEC culture permeability, but at micromolar concentrations it increased the permeability. The objective of the present study was to test the hypothesis that the changes in permeability were ... More
Binding of 13-HODE and 15-HETE to phospholipid bilayers, albumin, and intracellular fatty acid binding proteins. implications for transmembrane and intracellular transport and for protection from lipid peroxidation.
AuthorsEk-Von Mentzer BA, Zhang F, Hamilton JA
JournalJ Biol Chem
PubMed ID11278949
'Transport and utilization of fatty acids (FA) in cells is a multistep process that includes adsorption to and movement across the plasma membrane and binding to intracellular fatty acid binding proteins (FABP) in the cytosol. We monitored the transbilayer movement of several polyunsaturated FA and oxidation products (13-hydroxy octadecadienoic acid ... More
Amphotericin B and Nystatin show different activities on sterol-free vesicles.
AuthorsWhyte BS, Peterson RP, Hartsel SC
JournalBiochem Biophys Res Commun
PubMed ID2818579
'It has generally been assumed that the polyene antibiotics Nystatin and Amphotericin B cause membrane damage by the same mechanism. However, using kinetic fluorescence methods we have found that AmB and Nystatin have very different activities on sterol-free dioleoyl phosphatidylcholine and egg phosphatidylcholine small unilamellar vesicles. At very low AmB ... More
The classical receptive field surround of primate parasol ganglion cells is mediated primarily by a non-GABAergic pathway.
AuthorsMcMahon MJ, Packer OS, Dacey DM
JournalJ Neurosci
PubMed ID15084653
'Although the center-surround receptive field is a fundamental property of retinal ganglion cells, the circuitry that mediates surround inhibition remains controversial. We examined the contribution of horizontal cells and amacrine cells to the surround of parasol ganglion cells of macaque and baboon retina by measuring receptive field structure before and ... More
Site-directed mutagenesis identifies residues in uncoupling protein (UCP1) involved in three different functions.
AuthorsEchtay KS, Winkler E, Bienengraeber M, Klingenberg M
JournalBiochemistry
PubMed ID10727223
'Using site-specific mutagenesis, we have constructed several mutants of uncoupling protein (UCP1) from brown adipose tissue to investigate the function of acidic side chains at positions 27, 167, 209, and 210 in H(+) and Cl(-) transport as well as in nucleotide binding. The H(+) transport activity was measured with mitochondria ... More
Detection of a new enzyme for stereoselective hydrolysis of linalyl acetate using simple plate assays for the characterization of cloned esterases from Burkholderia gladioli.
AuthorsSchlacher A, Stanzer T, Osprian I, Mischitz M, Klingsbichel E, Faber K, Schwab H
JournalJ Biotechnol
PubMed ID9684341
'Plate assays were developed for the identification of specific hydrolytic activities of esterases from Burkholderia gladioli, cloned and expressed in Escherichia coli. Clones showing different substrate specificities were identified by fluorescence or azo-dye formation caused by the released alcohol moiety of the hydrolyzed substrates, or by colour change of pH ... More
Use of coherent control methods through scattering biological tissue to achieve functional imaging.
AuthorsDela Cruz JM, Pastirk I, Comstock M, Lozovoy VV, Dantus M
JournalProc Natl Acad Sci U S A
PubMed ID15569924
'We test whether coherent control methods based on ultrashort-pulse phase shaping can be applied when the laser light propagates through biological tissue. Our results demonstrate experimentally that the spectral-phase properties of shaped laser pulses optimized to achieve selective two-photon excitation survive as the laser pulses propagate through tissue. This observation ... More
Modulation by small hydrophobic molecules of valinomycin-mediated potassium transport across phospholipid vesicle membranes.
AuthorsClement NR, Gould MJ
JournalBiochemistry
PubMed ID6261799
'The effects of small hydrophobic molecules on valinomycin-mediated K+ transport in small unilamellar soybean phospholipid vesicles have been studied by using a vesicle-entrapped pH-sensitive hydrophilic fluorescence probe to monitor counterion-limited, passive H+ diffusion into vesicles after an abrupt decrease in external pH [Clement, N. R., & Gould, J. M. (1981) ... More
Characterization of an integral protein of the brush border membrane mediating the transport of divalent metal ions.
AuthorsKnöpfel M, Schulthess G, Funk F, Hauser H
JournalBiophys J
PubMed ID10920019
'The transport of Fe(2+) and other divalent transition metal ions across the intestinal brush border membrane (BBM) was investigated using brush border membrane vesicles (BBMVs) as a model. This transport is an energy-independent, protein-mediated process. The divalent metal ion transporter of the BBM is a spanning protein, very likely a ... More
In vitro characterization of a novel polymeric-based pH-sensitive liposome system.
AuthorsZignani M, Drummond DC, Meyer O, Hong K, Leroux JC
JournalBiochim Biophys Acta
PubMed ID10675515
'This study demonstrates rapid and pH-sensitive release of a highly water-soluble fluorescent aqueous content marker, pyranine, from egg phosphatidylcholine liposomes following incorporation of N-isopropylacrylamide (NIPA) copolymers in liposomal membranes. The pH-sensitivity of this system correlates with the precipitation of the copolymers at acidic pH. In vitro release can be significantly ... More
In the uncoupling protein (UCP-1) His-214 is involved in the regulation of purine nucleoside triphosphate but not diphosphate binding.
AuthorsEchtay KS, Bienengraeber M, Winkler E, Klingenberg M
JournalJ Biol Chem
PubMed ID9733725
'The nucleotide binding to uncoupling protein (UCP-1) of brown adipose tissue is regulated by pH. The binding pocket of the nucleotide phosphate moiety has been proposed to be controlled by the protonization of a carboxyl group (pK approximately 4.5) for both nucleoside diphosphates (NDP) and nucleoside triphosphates (NTP) (identified as ... More
Role of nitric oxide and cyclic guanosine 3',5'-monophosphate in the estrogen regulation of cervical epithelial permeability.
AuthorsGorodeski GI
JournalEndocrinology
PubMed ID10803574
'Treatment of cultured human cervical epithelia on filters with 17beta-estradiol increases paracellular permeability in a time- and dose-related manner (EC50, 1.1 nM). The objective of the present study was to understand the molecular mechanisms of estrogen action. In cultured human cervical epithelial cells the nitric oxide (NO) donors sodium nitroprusside ... More
Direct inhibitory effect of CCCP on the Cl(-)-H+ symporter of the guinea pig ileal brush-border membrane.
AuthorsAlvarado F, Vasseur M
JournalAm J Physiol
PubMed ID9486139
'The effect of carbonyl cyanide-m-chlorophenylhydrazone (CCCP) on Cl- uptake across the brush-border membrane (BBM) was quantified using 36Cl and BBM vesicles from guinea pig ileum. CCCP inhibited only partially both the pH gradient-activated Cl- uptake and Cl-/Cl- exchange activities present in these vesicles. In contrast, CCCP had no effect on ... More
Efficiency of cytoplasmic delivery by pH-sensitive liposomes to cells in culture.
AuthorsChu CJ, Dijkstra J, Lai MZ, Hong K, Szoka FC
JournalPharm Res
PubMed ID2172955
'The intracellular processing of pH-sensitive liposomes composed of cholesterylhemisuccinate (CHEMS) and dioleoylphosphatidylethanolamine (DOPE) by eukaryotic cell lines has been compared to non-pH-sensitive liposomes made of CHEMS and dioleoylphosphatidylcholine (DOPC). The pH-sensitive liposomes can deliver encapsulated fluorescent molecules [calcein, fluoresceinated dextran, fluoresceinated polypeptide, and diphtheria toxin A chain (DTA)] into the ... More
Isoprene formation in Bacillus subtilis: a barometer of central carbon assimilation in a bioreactor?
AuthorsShirk MC, Wagner WP, Fall R
JournalBiotechnol Prog
PubMed ID12363365
'Isoprene (2-methyl-1,3-butadiene) is a volatile hydrocarbon of uncertain function in Bacillus subtilis, and we hypothesized that it is an overflow metabolite produced during excess carbon utilization. Here we tested this idea for phase 2 of isoprene release, a phase that occurs during extracellular acetoin accumulation and its reassimilation. Phase 2 ... More
Regulation of the paracellular permeability of cultured human cervical epithelium by a nucleotide receptor.
AuthorsGorodeski GI, Hopfer U
JournalJ Soc Gynecol Investig
PubMed ID9420880
'OBJECTIVE: We sought to determine what type of regulation of transepithelial transport in leaky epithelium can occur at the level of paracellular permeability. METHODS: The epithelial permeability to the polar acid pyranine (Ppyr) and the transepithelial electrical resistance (R) were determined in cultured human cervical epithelium. RESULTS: Extracellular adenosine triphosphate ... More
Cell death-associated translocation of plasma membrane components induced by CTL.
AuthorsKawasaki Y, Saito T, Shirota-Someya Y, Ikegami Y, Komano H, Lee MH, Froelich CJ, Shinohara N, Takayama H
JournalJ Immunol
PubMed ID10779768
'In the very early stages of target cell apoptosis induced by CTL, we found that fluorescence of labeling probes of the target plasma membrane, such as N-(3-triethylammoniumpropyl)-4-(p-dibutylaminostyryl)pyridin ium dibromide (FM1-43), was translocated into intracellular membrane structures including nuclear envelope and mitochondria. This translocation was associated with the execution of CTL-mediated ... More
Subunit arrangement in V-ATPase from Thermus thermophilus.
AuthorsYokoyama K, Nagata K, Imamura H, Ohkuma S, Yoshida M, Tamakoshi M
JournalJ Biol Chem
PubMed ID12913005
'The V0V1-ATPase of Thermus thermophilus catalyzes ATP synthesis coupled with proton translocation. It consists of an ATPase-active V1 part (ABDF) and a proton channel V0 part (CLEGI), but the arrangement of each subunit is still largely unknown. Here we found that acid treatment of V0V1-ATPase induced its dissociation into two ... More
Measuring the adsorption of Fatty acids to phospholipid vesicles by multiple fluorescence probes.
AuthorsSimard JR, Kamp F, Hamilton JA,
JournalBiophys J
PubMed ID18296488
'Fatty acids (FA) are important nutrients that the body uses to regulate the storage and use of energy resources. The predominant mechanism by which long-chain fatty acids enter cells is still debated widely as it is unclear whether long-chain fatty acids require protein transporters to catalyze their transmembrane movement. We ... More
N-isopropylacrylamide copolymers for the preparation of pH-sensitive liposomes and polymeric micelles.
AuthorsLeroux J, Roux E, Le Garrec D, Hong K, Drummond DC
JournalJ Control Release
PubMed ID11389986
'Hydrophobically-modified copolymers of N-isopropylacrylamide bearing a pH-sensitive moiety were investigated for the preparation of pH-responsive liposomes and polymeric micelles. The copolymers having the hydrophobic anchor randomly distributed within the polymeric chain were found to more efficiently destabilize egg phosphatidylcholine (EPC)/cholesterol liposomes than the alkyl terminated polymers. Release of both a ... More
A novel technique for studying cellular function in human placenta: gestational changes in intracellular pH regulation.
AuthorsPowell TL, Illsley NP
JournalPlacenta
PubMed ID8916216
'This paper presents a new method for the study of cell function in primary human placental syncytiotrophoblast cells. Chorionic villous tissue fragments from term and first trimester placenta were loaded with fluorescent pH sensitive indicator dye HPTS and made adherent to a microscope cover-slip. The fragments were superfused and intracellular ... More
Effect of the arginine-82 to alanine mutation in bacteriorhodopsin on dark adaptation, proton release, and the photochemical cycle.
AuthorsBalashov SP, Govindjee R, Kono M, Imasheva E, Lukashev E, Ebrey TG, Crouch RK, Menick DR, Feng Y
JournalBiochemistry
PubMed ID8399176
'The pH dependence of the rate constant of dark adaptation (thermal isomerization from all-trans- to 13-cis-bR) drastically changes when Arg82 of bacteriorhodopsin is replaced by an alanine. In the wild type (WT) the rate decreases sharply between pH 2.5 and pH 5. In R82A the sharp decrease is shifted to ... More
Potassium-selective amphotericin B channels are predominant in vesicles regardless of sidedness.
AuthorsHartsel SC, Benz SK, Peterson RP, Whyte BS
JournalBiochemistry
PubMed ID1703016
'Amphotericin B (AmB) is a membrane-active antibiotic which has been shown to increase ion and small molecule permeability in a variety of model and biological membrane systems. A major mechanistic model, based on BLM systems, proposes that amphotericin forms barrellike pores with cholesterol which are cation selective when added to ... More
Different circuits for ON and OFF retinal ganglion cells cause different contrast sensitivities.
AuthorsZaghloul KA, Boahen K, Demb JB
JournalJ Neurosci
PubMed ID12684450
'The theory of "parallel pathways" predicts that, except for a sign reversal, ON and OFF ganglion cells are driven by a similar presynaptic circuit. To test this hypothesis, we measured synaptic inputs to ON and OFF cells as reflected in the subthreshold membrane potential. We made intracellular recordings from brisk-transient ... More
Low dielectric permittivity of water at the membrane interface: effect on the energy coupling mechanism in biological membranes.
AuthorsCherepanov DA, Feniouk BA, Junge W, Mulkidjanian AY
JournalBiophys J
PubMed ID12885673
'Protonmotive force (the transmembrane difference in electrochemical potential of protons, ) drives ATP synthesis in bacteria, mitochondria, and chloroplasts. It has remained unsettled whether the entropic (chemical) component of relates to the difference in the proton activity between two bulk water phases (deltapH(B)) or between two membrane surfaces (deltapH(S)). To ... More
Retinoids regulate tight junctional resistance of cultured human cervical cells.
AuthorsGorodeski GI, Eckert RL, Pal D, Utian WH, Rorke EA
JournalAm J Physiol
PubMed ID9374658
'The objective of the study was to determine the effect of retinoids on paracellular resistance across the cervical epithelium and the mechanisms involved. The experimental model was cultures of human CaSki cells on filters, which retain phenotypic characteristics of the endocervical epithelium. End points for paracellular resistance were measurements of ... More
Direct evidence for substrate-induced proton release in detergent-solubilized EmrE, a multidrug transporter.
AuthorsSoskine M, Adam Y, Schuldiner S
JournalJ Biol Chem
PubMed ID14701800
'A novel approach to study coupling of substrate and ion fluxes is presented. EmrE is an H(+)-coupled multidrug transporter from Escherichia coli. Detergent-solubilized EmrE binds substrate with high affinity in a pH-dependent mode. Here we show, for the first time in an ion-coupled transporter, substrate-induced release of protons in a ... More
Effects of hemagglutinin fusion peptide on poly(ethylene glycol)-mediated fusion of phosphatidylcholine vesicles.
AuthorsHaque ME, McCoy AJ, Glenn J, Lee J, Lentz BR
JournalBiochemistry
PubMed ID11714278
'The effects of hemagglutinin (HA) fusion peptide (X-31) on poly(ethylene glycol)- (PEG-) mediated vesicle fusion in three different vesicle systems have been compared: dioleoylphosphatidylcholine (DOPC) small unilamellar vesicles (SUV) and large unilamellar vesicles (LUV) and palmitoyloleoylphosphatidylcholine (POPC) large unilamellar perturbed vesicles (pert. LUV). POPC LUVs were asymmetrically perturbed by hydrolyzing ... More
Fluorescence of eosinophil leucocyte granules induced by 1-hydroxy-3,6,8-pyrenetrisulfonate. Visualization of differences in protein isoelectric points.
AuthorsTrigoso CI, Espada J, Stockert JC
JournalHistochem Cell Biol
PubMed ID7584562
'After treatment of horse, rat and human blood smears with alkaline solutions of 1-hydroxy-3,6,8-pyrenetrisulfonate (HPTS), eosinophil leucocyte granules were the unique cell components which showed a bright green fluorescence. When stained with HPTS at pH 10, the whole granule of horse eosinophils showed high emission which strongly diminished after washing ... More
Photoexcitation of the O-intermediate in bacteriorhodopsin mutant L93A.
AuthorsTóth-Boconádi R, Keszthelyi L, Stoeckenius W
JournalBiophys J
PubMed ID12770891
'During the extended lifetime of the O-state in bacteriorhodopsin (bR) mutant L93A, two substates have been distinguished. The first O-intermediate (OI) is in rapid equilibrium with N and apparently still has a 13-cis chromophore. OI undergoes a photoreaction with a small absorbance change, positive charge transport in the pumping direction, ... More
Proton transfer dynamics at the membrane/water interface: dependence on the fixed and mobile pH buffers, on the size and form of membrane particles, and on the interfacial potential barrier.
AuthorsCherepanov DA, Junge W, Mulkidjanian AY
JournalBiophys J
PubMed ID14747306
'Crossing the membrane/water interface is an indispensable step in the transmembrane proton transfer. Elsewhere we have shown that the low dielectric permittivity of the surface water gives rise to a potential barrier for ions, so that the surface pH can deviate from that in the bulk water at steady operation ... More
Cellular retention of liposome-delivered anionic compounds modulated by a probenecid-sensitive anion transporter.
AuthorsOh YK, Straubinger RM
JournalPharm Res
PubMed ID9327449
'PURPOSE: Drug carriers such as liposomes may enhance the intracellular delivery of therapeutic agents for infectious or neoplastic diseases. However, the mechanisms affecting cellular retention of liposome contents are understood poorly. We tested the hypothesis that retention of anionic compounds may be modulated by a nonspecific probenecid-sensitive anion transport mechanism, ... More
Meiosis reinitiation from the first prophase is dependent on the levels of intracellular Ca2+ and pH in oocytes of the bivalves Mactra chinensis and Limaria hakodatensis.
AuthorsDeguchi R, Osanai K
JournalDev Biol
PubMed ID7813778
'Naturally spawned oocytes of the marine bivalves Mactra chinensis and Limaria hakodatensis are arrested at the first prophase (prophase-I) and the first metaphase, respectively, until fertilization. Using the Ca2+ indicator fura-2 and the pH indicator 1-hydroxypyrene-3,6,8-trisulfonic acid, we have examined the respective effects of intracellular Ca2+ ([Ca2+]i) and pH (pHi) ... More
Electrically evoked dendritic pH transients in rat cerebellar Purkinje cells.
AuthorsWilloughby D, Schwiening CJ
JournalJ Physiol
PubMed ID12381821
'Our aim was to test the hypothesis that depolarization-induced intracellular pH (pH(i)) shifts in restricted regions (dendrites) of mammalian neurones might be larger and faster than those previously reported from the cell soma. We used confocal imaging of the pH-sensitive dye, HPTS, to measure pH changes in both the soma ... More
Bacteriorhodopsin expressed in Schizosaccharomyces pombe pumps protons through the plasma membrane.
AuthorsHildebrandt V, Fendler K, Heberle J, Hoffmann A, Bamberg E, Büldt G
JournalProc Natl Acad Sci U S A
PubMed ID8386375
'Bacterioopsin (bO) from Halobacterium salinarium ("Halobacterium halobium") has been functionally expressed in a heterologous system, the fission yeast Schizosaccharomyces pombe. Regeneration of bO to bacteriorhodopsin (bR) in S. pombe has been achieved in vivo by addition of the chromophore retinal to the culture medium, as shown for a retinal-negative mutant ... More
Protein-independent lead permeation through myelin lipid liposomes.
AuthorsDíaz RS, Monreal J
JournalMol Pharmacol
PubMed ID7723737
'We have investigated the permeability of protein-free myelin lipid liposomes to inorganic lead by using the fluorescent probes fura-2, oxonol V, pyranine, and carboxyfluorescein. Inorganic lead readily crossed the lipid bilayer, as detected with fura-2, to an extent that depended on the external pH and the total nominal lead concentration ... More
Two mechanisms of H+/OH- transport across phospholipid vesicular membrane facilitated by gramicidin A.
AuthorsPrabhananda BS, Kombrabail MH
JournalBiophys J
PubMed ID8968580
'Two rate-limiting mechanisms have been proposed to explain the gramicidin channel facilitated decay of the pH difference across vesicular membrane (delta pH) in the pH region 6-8 and salt (MCI, M+ = K+, Na+) concentration range 50-300 mM. 1) At low pH conditions (approximately 6), H+ transport through the gramicidin ... More
Dynamic organization of endocytic pathways in axons of cultured sympathetic neurons.
AuthorsOverly CC, Hollenbeck PJ
JournalJ Neurosci
PubMed ID8815888
'Despite the wealth of information about endocytic pathways in non-neuronal cells, little is known about these crucial sorting, recycling, and degradative pathways in neurons. In this report, we analyzed in detail the dynamic steady-state organization of endocytically derived organelles as they progress through the endosomal-lysosomal pathway in axons of live ... More
A kinetic method for measuring functional delivery of amphotericin B by drug delivery systems.
AuthorsPeterson RP, Benz SK, Whyte BS, Hartsel SC
JournalBiochim Biophys Acta
PubMed ID1851039
'The human toxicity of amphotericin B can be considerably reduced by associating the drug with liposomes of varying lipid compositions. Some lipid compositions are much more effective than others. We show that a simple kinetic fluorescence assay using pyranine as an indirect probe of amphotericin-induced K+ currents may be used ... More
A new method for the reconstitution of membrane proteins into giant unilamellar vesicles.
'In this work, we have investigated a new and general method for the reconstitution of membrane proteins into giant unilamellar vesicles (GUVs). We have analyzed systematically the reconstitution of two radically different membrane proteins, the sarcoplasmic reticulum Ca(2+)-ATPase and the H(+) pump bacteriorhodopsin. In a first step, our method involved ... More
Fatty acid-albumin complexes and the determination of the transport of long chain free fatty acids across membranes.
AuthorsCupp D, Kampf JP, Kleinfeld AM
JournalBiochemistry
PubMed ID15078093
'Understanding the mechanism that governs the transport of long chain free fatty acids (FFA) across lipid bilayers is critical for understanding transport across cell membranes. Conflicting results have been reported for lipid vesicles; most investigators report that flip-flop occurs within the resolution time of the method (<5 ms) and that ... More
Temperature-sensitive yeast mutants defective in mitochondrial inheritance.
AuthorsMcConnell SJ, Stewart LC, Talin A, Yaffe MP
JournalJ Cell Biol
PubMed ID2202739
'The distribution of mitochondria to daughter cells is an essential feature of mitotic cell growth, yet the molecular mechanisms facilitating this mitochondrial inheritance are unknown. We have isolated mutants of Saccharomyces cerevisiae that are temperature-sensitive for the transfer of mitochondria into a growing bud. Two of these mutants contain single, ... More
Ca2+ transport by reconstituted synaptosomal ATPase is associated with H+ countertransport and net charge displacement.
AuthorsSalvador JM, Inesi G, Rigaud JL, Mata AM
JournalJ Biol Chem
PubMed ID9660785
'The synaptosomal plasma membrane Ca2+-ATPase (PMCA) purified from pig brain was reconstituted with liposomes prepared by reverse phase evaporation at a lipid to protein ratio of 150/1 (w/w). ATP-dependent Ca2+ uptake and H+ ejection by the reconstituted proteoliposomes were demonstrated by following light absorption and fluorescence changes undergone by arsenazo ... More
Kinetics for development of gramicidin-induced ion permeability in unilamellar phospholipid vesicles.
AuthorsClement NR, Gould JM
JournalBiochemistry
PubMed ID6164386
'Two kinetics for the development of gramicidin-dependent cation permeability in small unilamellar vesicles have been studied by using a vesicle-entrapped, pH-sensitive fluorescence probe to continuously report changes in intravesicular pH. The incorporation of 4-5 gramicidin dimers/vesicle was sufficient to increase the proton and counterion permeability of that vesicle by several ... More
Prolonged display or rapid internalization of the IgG-binding protein ZZ anchored to the surface of cells using the diphtheria toxin T domain.
AuthorsNizard P, Chenal A, Beaumelle B, Fourcade A, Gillet D
JournalProtein Eng
PubMed ID11477224
'We have shown previously that the diphtheria toxin transmembrane domain (T) may function as a membrane anchor for soluble proteins fused at its C-terminus. Binding to membranes is triggered by acidic pH. Here, we further characterized this anchoring device. Soluble proteins may be fused at the N-terminus of the T ... More
The arabidopsis Na+/H+ exchanger AtNHX1 catalyzes low affinity Na+ and K+ transport in reconstituted liposomes.
'In saline environments, plants accumulate Na(+) in vacuoles through the activity of tonoplast Na(+)/H(+) antiporters. The first gene for a putative plant vacuolar Na(+)/H(+) antiporter, AtNHX1, was isolated from Arabidopsis and shown to increase plant tolerance to NaCl. However, AtNHX1 mRNA was up-regulated by Na(+) or K(+) salts in plants ... More
Bipolar cells contribute to nonlinear spatial summation in the brisk-transient (Y) ganglion cell in mammalian retina.
AuthorsDemb JB, Zaghloul K, Haarsma L, Sterling P
JournalJ Neurosci
PubMed ID11567034
'The receptive field of the Y-ganglion cell comprises two excitatory mechanisms: one integrates linearly over a narrow field, and the other integrates nonlinearly over a wide field. The linear mechanism has been attributed to input from bipolar cells, and the nonlinear mechanism has been attributed to input from a class ... More
pH probes respond to redox changes in cytochrome o.
AuthorsSedgwick EG, Bragg PD
JournalArch Biochem Biophys
PubMed ID2173483
'N-Phenylnaphthylamine (NPN) has been used previously to probe the fluidity or microviscosity of membrane lipids. We have shown (Sedgwick, E. G., and Bragg, P.D. (1988) FEBS Lett. 229, 127-130) that the fluorescence intensity of this probe abruptly increases upon depletion of the oxygen content of a medium by respiring cytochrome ... More
Utilization of monensin for detection of microdomains in cholesterol containing membrane.
AuthorsBransburg-Zabary S, Nachliel E, Gutman M
JournalBiochim Biophys Acta
PubMed ID8972698
'The effect of cholesterol on the monensin mediated proton-cation exchange reaction was measured in the time-resolved domain. The experimental system consisted of a black lipid membrane equilibrated with monensin (Nachliel, E., Finkelstein, Y. and Gutman, M. (1996) Biochim. Biophys. Acta 1285, 131-145). The membrane separated two compartments containing electrolyte solutions ... More
The current-voltage relationships of liposomes and mitochondria.
AuthorsO'Shea PS, Petrone G, Casey RP, Azzi A
JournalBiochem J
PubMed ID6331396
'Current-voltage relationships were determined for various membrane systems. We show that phospholipid and mitochondrial membranes exhibit linear relations between H+ flux and pH gradients. These membranes, however, exhibited non-linear relationships when the applied voltage was a membrane potential. The current-voltage relationship approximated to an exponential function. This relationship was found ... More
Potential contribution of a voltage-activated proton conductance to acid extrusion from rat hippocampal neurons.
AuthorsCheng YM, Kelly T, Church J,
JournalNeuroscience
PubMed ID18201832
'We examined the potential contribution of a voltage-gated proton conductance (gH+) to acid extrusion from cultured postnatal rat hippocampal neurons. In neurons loaded with Ca2+- and/or pH-sensitive fluorophores, transient exposures to 25-139.5 mM external K+ (K+o) or 20 microM veratridine in the presence of 2 mM Ca2+o (extracellular pH (pHo) ... More
Effect of serum on the intracellular pH of BALB/c-3T3 cells: serum deprivation causes changes in sensitivity of cells to serum.
AuthorsMartinez R, Gillies RJ, Giuliano KA
JournalJ Cell Physiol
PubMed ID2840441
'One of the earliest responses of quiescent mammalian cells to the addition of serum is an increase in intracellular pH (pHin). This pHin change is generally believed to be due to an increased activity of Na+/H+ exchange. A number of investigators have observed steady-state differences in pHin between cells in ... More
Rapid flip-flop of oleic acid across the plasma membrane of adipocytes.
AuthorsKamp F, Guo W, Souto R, Pilch PF, Corkey BE, Hamilton JA
JournalJ Biol Chem
PubMed ID12499383
'Nonesterified long-chain fatty acids may enter cells by free diffusion or by membrane protein transporters. A requirement for proteins to transport fatty acids across the plasma membrane would imply low partitioning of fatty acids into the membrane lipids, and/or a slower rate of diffusion (flip-flop) through the lipid domains compared ... More
GPI-anchored influenza hemagglutinin induces hemifusion to both red blood cell and planar bilayer membranes.
AuthorsMelikyan GB, White JM, Cohen FS
JournalJ Cell Biol
PubMed ID7593189
'Under fusogenic conditions, fluorescent dye redistributed from the outer monolayer leaflet of red blood cells (RBCs) to cells expressing glycophosphatidylinositol-anchored influenza virus hemagglutinin (GPI-HA) without transfer of aqueous dye. This suggests that hemifusion, but not full fusion, occurred (Kemble, G. W., T. Danieli, and J. M. White. 1994. Cell. 76:383-391). ... More
Buffer effects on electric signals of light-excited bacteriorhodopsin.
AuthorsTóth-Boconádi R, Dér A, Keszthelyi L
JournalBiophys J
PubMed ID10827993
'Buffers change the electric signals of light-excited bacteriorhodopsin molecules in purple membrane if their concentration and the pH of the low-salt solution are properly selected. "Positive" buffers produce a positive component, and "negative" buffers a negative component in addition to the signals due to proton pumping. Measurement of the buffer ... More
Proton transport by halorhodopsin.
AuthorsVáró G, Brown LS, Needleman R, Lanyi JK
JournalBiochemistry
PubMed ID8639608
'In halorhodopsin from Natronobacterium pharaonis, a light-driven chloride pump, the chloride binding site also binds azide. When azide is bound at this location the retinal Schiff base transiently deprotonates after photoexcitation with light > 530 nm, like in the light-driven proton pump bacteriorhodopsin. As in the photocycle of bacteriorhodopsin, pyranine ... More
Structure of the developing pea seed coat and the post-phloem transport pathway of nutrients.
AuthorsVan Dongen JT, Ammerlaan AM, Wouterlood M, Van Aelst AC, Borstlap AC
JournalAnn Bot (Lond)
PubMed ID12714370
'An important function of the seed coat is to deliver nutrients to the embryo. To relate this function to anatomical characteristics, the developing seed coat of pea (Pisum sativum L.) was examined by light- and cryo-scanning electron microscopy (cryo-SEM) from the late pre-storage phase until the end of seed filling. ... More
Spatial organization of bacteriorhodopsin in model membranes. Light-induced mobility changes.
AuthorsKahya N, Wiersma DA, Poolman B, Hoekstra D
JournalJ Biol Chem
PubMed ID12167614
'Bacteriorhodopsin is a proton-transporting membrane protein in Halophilic archaea, and it is considered a prototype of membrane transporters and a model for G-protein-coupled receptors. Oligomerization of the protein has been reported, but it is unknown whether this feature is correlated with, for instance, light activation. Here, we have addressed this ... More
Dissociation of long and very long chain fatty acids from phospholipid bilayers.
AuthorsZhang F, Kamp F, Hamilton JA
JournalBiochemistry
PubMed ID8973175
'Dissociation of fatty acids (FA) from and transbilayer movement (flip-flop) in small unilamellar phosphatidylcholine vesicles (SUV) were monitored by measuring the pH inside the vesicle with an entrapped water-soluble fluorophore, pyranin. With a pH gradient imposed upon SUV preloaded with FA, the rate of flip-flop of saturated very long chain ... More
Kinetic studies of proton transfer in the microenvironment of a binding site.
AuthorsGutman M, Huppert D, Nachliel E
JournalEur J Biochem
PubMed ID6276178
'Excitation of 8-hydroxypyrene 1,3,6-trisulfonate to its first electronic singlet state converts the compound from weak base (pK degrees = 7.7) into a strong acid (pK* = 0.5). The dissociation of the proton in water or dilute salt solution is a very fast reaction, K12 = 1 X 10(10) S-1. In ... More
Conjugation of apolipoprotein B with liposomes and targeting to cells in culture.
AuthorsLundberg B, Hong K, Papahadjopoulos D
JournalBiochim Biophys Acta
PubMed ID8391843
'Mixed phospholipid/cholesterol (2:1 molar ratio) liposomes were conjugated with native and acetylated apolipoprotein B (apoB), the protein part of low density lipoprotein (LDL). The objective was to increase the specificity of the cellular uptake of liposomes by utilization of the LDL and scavenger receptor pathways. The method of choice for ... More
Comparison of simultaneous pH measurements made with 8-hydroxypyrene-1,3,6-trisulphonic acid (HPTS) and pH-sensitive microelectrodes in snail neurones
AuthorsWilloughby D, Thomas RC, Schwiening CJ
JournalPflugers Arch
PubMed ID9683736
'We have evaluated the pyrene-based ratiometric fluorescent dye, 8-hydroxypyrene-1,3,6-trisulphonic acid (HPTS), by using it in conjunction with glass pH-sensitive microelectrodes to measure intracellular pH (pHi) in voltage-clamped snail neurones. Intracellular acidification with propionic acid, and alkalinization following the activation of H+ channels allowed the calibration of the dye to be ... More
Photochemical reaction cycle and proton transfers in Neurospora rhodopsin.
'It was recently found that NOP-1, a membrane protein of Neurospora crassa, shows homology to haloarchaeal rhodopsins and binds retinal after heterologous expression in Pichia pastoris. We report on spectroscopic properties of the Neurospora rhodopsin (NR). The photocycle was studied with flash photolysis and time-resolved Fourier-transform infrared spectroscopy in the ... More
Bacteriorhodopsin analog regenerated with 13-desmethyl-13-iodoretinal.
AuthorsHiraki K, Hamanaka T, Zheng XG, Shinada T, Kim JM, Yoshihara K, Kito Y
JournalBiophys J
PubMed ID12496112
'The retinal analog 13-desmethyl-13-iodoretinal (13-iodoretinal) was newly synthesized and incorporated into apomembranes to reconstitute bacteriorhodopsin analog 13-I-bR. The absorption maximum was 598 nm and 97% of the chromophore was an all-trans isomer in the dark- and light-adapted state. Upon flash illumination, 13-I-bR underwent a transient spectral change in which a ... More
The effects of intracellular pH changes on resting cytosolic calcium in voltage-clamped snail neurones.
AuthorsWilloughby D, Thomas R, Schwiening C
JournalJ Physiol
PubMed ID11158272
'We have investigated the effects of changing intracellular pH on intracellular free calcium concentration ([Ca2+]i) in voltage-clamped neurones of the snail Helix aspersa. Intracellular pH (pHi) was measured using the fluorescent dye 8-hydroxypyrene-1,3,6-trisulphonic acid (HPTS) and changed using weak acids and weak bases. Changes in [Ca2+]i were recorded using either ... More
Continuous measurement of the cytoplasmic pH in Lactococcus lactis with a fluorescent pH indicator.
AuthorsMolenaar D, Abee T, Konings WN
JournalBiochim Biophys Acta
PubMed ID1958707
'The cytoplasmic pH of Lactococcus lactis was studied with the fluorescent pH indicator 2'',7''-bis-(2-carboxyethyl)-5 (and-6)-carboxyfluorescein (BCECF). A novel method was applied for loading bacterial cells with BCECF, which consists of briefly treating a dense cell suspension with acid in the presence of the probe. This results in a pH gradient, ... More
The 'delta pH'-probe 9-aminoacridine: response time, binding behaviour and dimerization at the membrane.
AuthorsGrzesiek S, Dencher NA
JournalBiochim Biophys Acta
PubMed ID3349072
'The fluorescence quenching of 9-aminoacridine (9-AA) after imposition of a transmembrane pH gradient (inside acidic) in liposomes has been investigated for a number of different lipid systems. The initial fluorescence decrease after a rapid pH jump, induced in the extravesicular medium by a stopped-flow mixing technique, was ascribed to a ... More
Multiple innervation of tonic endplates revealed by activity-dependent uptake of fluorescent probes.
AuthorsLichtman JW, Wilkinson RS, Rich MM
JournalNature
PubMed ID3982503
'During development of the vertebrate nervous system, there is a widespread reduction in the number of axons innervating target cells. This phenomenon, often called synapse elimination, has been particularly well studied at the neuromuscular junction of developing twitch muscle fibres: following a period of polyneuronal innervation, axonal branches are retracted, ... More
Characterization of paracellular permeability in cultured human cervical epithelium: regulation by extracellular adenosine triphosphate.
AuthorsGorodeski GI, Merlin D, De Santis BJ, Frieden KA, Hopfer U, Eckert RL, Utian WH, Romero MF
JournalJ Soc Gynecol Investig
PubMed ID9419776
'OBJECTIVE: The purpose of the present study was to compare the permeability and regulation of paracellular transport in human cervical cells with those in epithelial cells of other organs. METHODS: Cervical cells (ECE16-1, Caski, and HT3) were grown on filters, and transepithelial electrical conductance (GT) and the permeability to pyranine ... More
Carbohydrate recognition by boronolectins, small molecules, and lectins.
AuthorsJin S, Cheng Y, Reid S, Li M, Wang B,
JournalMed Res Rev
PubMed ID19291708
'Carbohydrates are known to mediate a large number of biological and pathological events. Small and macromolecules capable of carbohydrate recognition have great potentials as research tools, diagnostics, vectors for targeted delivery of therapeutic and imaging agents, and therapeutic agents. However, this potential is far from being realized. One key issue ... More
The Ppz protein phosphatases are key regulators of K+ and pH homeostasis: implications for salt tolerance, cell wall integrity and cell cycle progression.
AuthorsYenush L, Mulet JM, Ariño J, Serrano R
JournalEMBO J
PubMed ID11867520
'The yeast Ppz protein phosphatases and the Hal3p inhibitory subunit are important determinants of salt tolerance, cell wall integrity and cell cycle progression. We present several lines of evidence showing that these disparate phenotypes are connected by the fact that Ppz regulates K+ transport. First, salt tolerance, cell wall integrity ... More
H+/K+ exchange in reconstituted yeast plasma membrane vesicles.
AuthorsRamírez J, Peña A, Montero-Lomelí M
JournalBiochim Biophys Acta
PubMed ID8972701
'The activity of a putative H+/K+ exchange system in the plasma membrane of yeast was studied following the alkalinization of the interior of vesicles prepared with lecithin and yeast plasma membrane containing pyranine entrapped inside. The fluorescence of pyranine was used as an indicator of the internal pH of the ... More
Measurement of the cytoplasmic pH of Dictyostelium discoideum using a low light level microspectrofluorometer.
AuthorsFurukawa R, Wampler JE, Fechheimer M
JournalJ Cell Biol
PubMed ID2849608
'Pyranine was employed as a sensitive pH indicator in a low light level microspectrofluorometer. The in vivo and in vitro standard curves of the 460/410-nm fluorescence excitation ratio of pyranine as a function of pH are identical. Therefore, pyranine is specifically sensitive to cytoplasmic pH in Dictyostelium. The cytoplasmic pH ... More
A novel intracellular K+/H+ antiporter related to Na+/H+ antiporters is important for K+ ion homeostasis in plants.
AuthorsVenema K, Belver A, Marin-Manzano MC, Rodríguez-Rosales MP, Donaire JP
JournalJ Biol Chem
PubMed ID12695519
'In this study we have identified the first plant K+/H+ exchanger, LeNHX2 from tomato (Lycopersicon esculentum Mill. cv. Moneymaker), which is a member of the intracellular NHX exchanger protein family. The LeNHX2 protein, belonging to a subfamily of plant NHX proteins closely related to the yeast NHX1 protein, is abundant ... More
Functional reconstitution in lipid vesicles of influenza virus M2 protein expressed by baculovirus: evidence for proton transfer activity.
AuthorsSchroeder C, Ford CM, Wharton SA, Hay AJ
JournalJ Gen Virol
PubMed ID7527837
'The influenza virus M2 protein was expressed from a recombinant baculovirus in Spodoptera frugiperda Sf9 cells, purified and reconstituted into artificial membrane vesicles. The specific inhibitor amantadine overcame the toxic activity of the protein and boosted the rate of M2 synthesis by a factor of 10, allowing yields of about ... More
The fluorescent indicator pyranine is suitable for measuring stromal and cameral pH in vivo.
'Three pH-sensitive fluorescent indicators (fluorescein, bis-carboxyethyl-carboxyfluorescein and pyranine) were studied to determine their usefulness as probes for the living cornea and anterior chamber. Of the three dyes, pyranine had properties which render it almost ideally suited for this purpose. Adequate concentrations are reached in the cornea and anterior chamber after ... More
Evidence for participation of GTP-binding proteins in elicitation of the rapid oxidative burst in cultured soybean cells.
AuthorsLegendre L, Heinstein PF, Low PS
JournalJ Biol Chem
PubMed ID1400332
'GTP-binding proteins have been shown to serve as second messengers in the transduction of hormone signals across animal cell plasma membranes. We present here three lines of evidence to demonstrate that GTP-binding proteins are also involved in the elicitation of the defense response of cultured soybean cells. First, the antigen-binding ... More
Vaginal-cervical epithelial permeability decreases after menopause.
AuthorsGorodeski GI
JournalFertil Steril
PubMed ID11591410
'OBJECTIVE: To determine the effects of menopause (aging and E) on vaginal-cervical epithelial paracellular permeability. DESIGN: Experimental, basic clinical research. SETTING: Academic research environment. PATIENT(S):Premenopausal, perimenopausal, and postmenopausal women, aged 35-65 years. INTERVENTION(S): Primary to tertiary cultures of normal human ectocervical epithelial cells on filters. Cells were outgrown from surgically ... More
Prodigiosins as a new group of H+/Cl- symporters that uncouple proton translocators.
AuthorsSato T, Konno H, Tanaka Y, Kataoka T, Nagai K, Wasserman HH, Ohkuma S
JournalJ Biol Chem
PubMed ID9705273
'We reported previously (Kataoka, T., Muroi, M., Ohkuma, S., Waritani, T., Magae, J., Takatsuki, A., Kondo, S., Yamasaki, M., and Nagai, K. (1995) FEBS Lett. 359, 53-59) that prodigiosin 25-C uncoupled vacuolar H+-ATPase, inhibited vacuolar acidification, and affected glycoprotein processing. In the present study we show that prodigiosins (prodigiosin, metacycloprodigiosin, ... More
V-Type H+-ATPase/synthase from a thermophilic eubacterium, Thermus thermophilus. Subunit structure and operon.
AuthorsYokoyama K, Ohkuma S, Taguchi H, Yasunaga T, Wakabayashi T, Yoshida M
JournalJ Biol Chem
PubMed ID10788522
'V-type ATPase (V(o)V(1)) capable of ATP-driven H(+) pumping and of H(+) gradient driven ATP synthesis was isolated from a thermophilic eubacterium, Thermus thermophilus. When the enzyme was analyzed by gel electrophoresis in the presence of sodium dodecyl sulfate, it showed eight polypeptide bands of which four were subunits of V(1). ... More
On the protein residues that control the yield and kinetics of O(630) in the photocycle of bacteriorhodopsin.
AuthorsLi Q, Bressler S, Ovrutsky D, Ottolenghi M, Friedman N, Sheves M
JournalBiophys J
PubMed ID10620299
'The effects of pH on the yield (phi(r)), and on the apparent rise and decay constants (k(r), k(d)), of the O(630) intermediate are important features of the bacteriorhodopsin (bR) photocycle. The effects are associated with three titration-like transitions: 1) A drop in k(r), k(d), and phi(r) at high pH [pK(a)(1) ... More
Evolution of lipidic structures during model membrane fusion and the relation of this process to cell membrane fusion.
AuthorsLee J, Lentz BR
JournalBiochemistry
PubMed ID9174340
'The sequence of events involved in poly(ethylene glycol)-mediated fusion of small unilamellar vesicles (SUVs) has been studied. Fusion events were monitored using light scattering for vesicle aggregation, the fluorescence lifetime of membrane probe lipids (DPHpPC and NBD-PS) for membrane mixing, the aqueous fluorescent marker (Tb3+/DPA and H+/HPTS) for contents mixing; ... More
Cytoplasmic pH of Dictyostelium discoideum amebae during early development: identification of two cell subpopulations before the aggregation stage.
AuthorsFurukawa R, Wampler JE, Fechheimer M
JournalJ Cell Biol
PubMed ID2161854
'Development of the cellular slime mold Dictyostelium discoideum is initiated by the removal of nutrients, and results in formation of a mature fruiting body composed of two cell types, the stalk and spore cells. A considerable body of evidence supports the hypothesis that cytoplasmic pH may be an essential regulator ... More