Sodium and chloride concentrations, pH, and depth of airway surface liquid in distal airways.
AuthorsSong Y, Thiagarajah J, Verkman AS
JournalJ Gen Physiol
PubMed ID14557401
The composition and depth of the airway surface liquid (ASL) are key parameters in airway physiology that are thought to be important in the pathophysiology of cystic fibrosis and other diseases of the airways. We reported novel fluorescent indicator and microscopy methods to measure [Na+], [Cl-], pH, and depth of ... More
Calcium permeability of the neuronal nuclear envelope: evaluation using confocal volumes and intracellular perfusion.
AuthorsO'Malley DM
JournalJ Neurosci
PubMed ID7931542
'In many calcium-imaging studies, the nuclear envelope appears to maintain a gradient of free calcium between the nucleus and cytosol. This issue was examined by loading amphibian sympathetic neurons with the calcium indicator fluo 3 via whole-cell patch clamping. Confocal optical sectioning allowed acquisition of independent calibration curves for the ... More
Bicarbonate secretion in interlobular ducts from guinea-pig pancreas.
AuthorsIshiguro H, Steward MC, Wilson RW, Case RM
JournalJ Physiol
PubMed ID8866361
'1. The transport of HCO3- across the luminal membrane of pancreatic duct cells was studied by monitoring the luminal pH of isolated guinea-pig interlobular ducts after microinjection of an extracellular fluoroprobe, the dextran conjugate of 2'7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF-dextran). Luminal Cl- concentration was also measured by microfluorometry following microinjection of the dextran ... More
Noninvasive in vivo fluorescence measurement of airway-surface liquid depth, salt concentration, and pH.
AuthorsJayaraman S, Song Y, Vetrivel L, Shankar L, Verkman AS
JournalJ Clin Invest
PubMed ID11160155
'The concentration of salt in the thin layer of fluid at the surface of large airways, the airway-surface liquid (ASL), is believed to be of central importance in airway physiology and in the pathophysiology of cystic fibrosis. Invasive sampling methods have yielded a wide range of ASL [NaCl] from 40 ... More
The role of intracellular calcium and pH during fertilization and egg activation in the hydrozoan Phialidium.
AuthorsFreeman G, Ridgway EB
JournalDev Biol
PubMed ID8095477
'A calcium transient occurs at fertilization in the eggs of the hydrozoans Mitrocomella and Phialidium. The eggs of Phialidium have an intracellular pH (pHi) of 7.6-7.95. There is no increase in pHi following fertilization. Both calcium ionophore and ammonia treatments activate Phialidium eggs. Calcium ionophore causes a calcium transient without ... More
Heterogeneity of the changes in cytoplasmic pH upon serum stimulation of quiescent fibroblasts.
AuthorsBright GR, Whitaker JE, Haugland RP, Taylor DL
JournalJ Cell Physiol
PubMed ID2478571
'Addition of mitogens to quiescent cells results in rapid ionic changes in the cytoplasm, including pH. We studied the changes in cytoplasmic pH in single Swiss 3T3 cells upon serum stimulation using fluorescence ratio imaging microscopy. Quiescence was attained using two approaches, serum deprivation of subconfluent cells and confluence. All ... More
Changes in cytosolic pH within Arabidopsis root columella cells play a key role in the early signaling pathway for root gravitropism.
AuthorsScott AC, Allen NS
JournalPlant Physiol
PubMed ID10594116
'Ratiometric wide-field fluorescence microscopy with 1'',7''- bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF)-dextran demonstrated that gravistimulation leads to rapid changes in cytoplasmic pH (pHc) in columella cells of Arabidopsis roots. The pHc of unstimulated columella cells in tiers 2 and 3, known sites of graviperception (E.B. Blancaflor, J.B. Fasano, S. Gilroy [1998] Plant Physiol 116: ... More
Acidification of vasopressin-induced endosomes in toad urinary bladder.
AuthorsEmma F, Harris HW, Strange K
JournalAm J Physiol
PubMed ID7519404
'It is well established that water channels (WC) are removed from the apical membrane of vasopressin-sensitive epithelia by endocytosis. The processing and the ultimate fate of endocytosed WC is, however, incompletely understood. In many cells, endosome acidification plays an important role in the processing and sorting of endocytosed proteins. Endosome ... More
Growing pollen tubes possess a constitutive alkaline band in the clear zone and a growth-dependent acidic tip.
'Using both the proton selective vibrating electrode to probe the extracellular currents and ratiometric wide-field fluorescence microscopy with the indicator 2'', 7''-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein (BCECF)-dextran to image the intracellular pH, we have examined the distribution and activity of protons (H+) associated with pollen tube growth. The intracellular images reveal that lily pollen ... More
Degradation of polyubiquitinated cyclin B is blocked by the MAPK pathway at the metaphase I arrest in starfish oocytes.
AuthorsOita E, Harada K, Chiba K
JournalJ Biol Chem
PubMed ID14985367
'In the starfish ovary, maturing oocytes stimulated by 1-methyladenine undergo synchronous germinal vesicle breakdown and then arrest in metaphase of the first meiotic division (metaphase I). Immediately after spawning, an increase of intracellular pH (pH(i)) from approximately 7.0 to approximately 7.3 is induced by Na(+)/H(+) antiporter in oocytes, and meiosis ... More
Functional polarity of Na+/H+ and Cl-/HCO3- exchangers in a rat cholangiocyte cell line.
AuthorsSpirlì C, Granato A, Zsembery K, Anglani F, Okolicsányi L, LaRusso NF, Crepaldi G, Strazzabosco M
JournalAm J Physiol
PubMed ID9843758
'Intrahepatic bile duct cells (cholangiocytes) play an important role in the secretion and alkalinization of bile. Both Na+/H+ exchange (NHE) and Cl-/HCO-3 exchange (AE) contribute to these functions, but their functional distribution between the apical and basolateral membrane domains remains speculative. We have addressed this issue in a normal rat ... More
Isolation of functional polarized bile duct units from mouse liver.
AuthorsCho WK, Mennone A, Boyer JL
JournalAm J Physiol Gastrointest Liver Physiol
PubMed ID11208546
'The development of genetically altered murine animals has generated a need for in vitro systems in the mouse. We have now characterized a novel isolated bile duct unit (IBDU) preparation from the mouse to facilitate such studies. The mouse IBDU is isolated by portal perfusion of collagenase, blunt dissection, further ... More
Fluorescence ratio imaging microscopy.
AuthorsBright GR, Fisher GW, Rogowska J, Taylor DL
JournalMethods Cell Biol
PubMed ID2648109
Activation of lysosomal function during dendritic cell maturation.
AuthorsTrombetta ES, Ebersold M, Garrett W, Pypaert M, Mellman I
JournalScience
PubMed ID12610307
In response to a variety of stimuli, dendritic cells (DCs) transform from immature cells specialized for antigen capture into mature cells specialized for T cell stimulation. During maturation, the DCs acquire an enhanced capacity to form and accumulate peptide-MHC (major histocompatibility complex) class II complexes. Here we show that a ... More
AuthorsKo SB, Naruse S, Kitagawa M, Ishiguro H, Murakami M, Hayakawa T
JournalAm J Physiol
PubMed ID10409150
The effects of arginine vasopressin (AVP) on pancreatic ductal secretion were studied in guinea pigs. In the isolated vascularly perfused pancreas, AVP reduced secretin-stimulated fluid secretion and increased the vascular resistance when the perfusion rate was held constant. In the isolated interlobular duct segments, AVP inhibited secretin-stimulated fluid secretion, indicating ... More
Metaphase I arrest of starfish oocytes induced via the MAP kinase pathway is released by an increase of intracellular pH.
AuthorsHarada K, Oita E, Chiba K
JournalDevelopment
PubMed ID12925585
Reinitiation of meiosis in oocytes usually occurs as a two-step process during which release from the prophase block is followed by an arrest in metaphase of the first or second meiotic division [metaphase I (MI) or metaphase II (MII)]. The mechanism of MI arrest in meiosis is poorly understood, although ... More
Elicitor-activated phospholipase A(2) generates lysophosphatidylcholines that mobilize the vacuolar H(+) pool for pH signaling via the activation of Na(+)-dependent proton fluxes.
AuthorsViehweger K, Dordschbal B, Roos W
JournalPlant Cell
PubMed ID12119371
The elicitation of phytoalexin biosynthesis in cultured cells of California poppy involves a shift of cytoplasmic pH via the transient efflux of vacuolar protons. Intracellular effectors of vacuolar proton transport were identified by a novel in situ approach based on the selective permeabilization of the plasma membrane for molecules of ... More
Role of airway surface liquid and submucosal glands in cystic fibrosis lung disease.
AuthorsVerkman AS, Song Y, Thiagarajah JR
JournalAm J Physiol Cell Physiol
PubMed ID12475759
Cystic fibrosis (CF) is caused by mutations in the CF transmembrane conductance regulator (CFTR) protein, an epithelial chloride channel expressed in the airways, pancreas, testis, and other tissues. A central question is how defective CFTR function in CF leads to chronic lung infection and deterioration of lung function. Several mechanisms ... More
Vacuole membrane fusion: V0 functions after trans-SNARE pairing and is coupled to the Ca2+-releasing channel.
AuthorsBayer MJ, Reese C, Buhler S, Peters C, Mayer A
JournalJ Cell Biol
PubMed ID12876274
Pore models of membrane fusion postulate that cylinders of integral membrane proteins can initiate a fusion pore after conformational rearrangement of pore subunits. In the fusion of yeast vacuoles, V-ATPase V0 sectors, which contain a central cylinder of membrane integral proteolipid subunits, associate to form a transcomplex that might resemble ... More
A small molecule CFTR inhibitor produces cystic fibrosis-like submucosal gland fluid secretions in normal airways.
AuthorsThiagarajah JR, Song Y, Haggie PM, Verkman AS
JournalFASEB J
PubMed ID15001557
Airway submucosal glands have been proposed as a primary site for initiating and sustaining airway disease in cystic fibrosis (CF). However, it has been difficult to define the role of CFTR in gland fluid secretion because of concerns in interpreting experiments on diseased CF human airways subjected to chronic infection ... More
Selective cytotoxicity of intracellular amyloid beta peptide1-42 through p53 and Bax in cultured primary human neurons.
AuthorsZhang Y, McLaughlin R, Goodyer C, LeBlanc A
JournalJ Cell Biol
PubMed ID11815632
Extracellular amyloid beta peptides (Abetas) have long been thought to be a primary cause of Alzheimer's disease (AD). Now, detection of intracellular neuronal Abeta1--42 accumulation before extracellular Abeta deposits questions the relevance of intracellular peptides in AD. In the present study, we directly address whether intracellular Abeta is toxic to ... More
Dynamic behavior of rod photoreceptor disks.
AuthorsChen C, Jiang Y, Koutalos Y
JournalBiophys J
PubMed ID12202366
Eukaryotic cells use membrane organelles, like the endoplasmic reticulum or the Golgi, to carry out different functions. Vertebrate rod photoreceptors use hundreds of membrane sacs (the disks) for the detection of light. We have used fluorescent tracers and single cell imaging to study the properties of rod photoreceptor disks. Labeling ... More
Sodium chloride reduces growth and cytosolic calcium, but does not affect cytosolic pH, in root hairs of Arabidopsis thaliana L.
AuthorsHalperin SJ, Gilroy S, Lynch JP
JournalJ Exp Bot
PubMed ID12654878
The effects of salinity (NaCl) stress on growth, cytosolic Ca(2+) gradients and cytosolic pH homeostasis of root hairs of Arabidopsis thaliana are assessed here. Neither cytosolic Ca(2+) nor pH at the hair apex were significantly affected by 20 min exposure of up to 90 mM NaCl or of up to ... More
Absence of an intracellular pH change following fertilisation of the mouse egg.
AuthorsKline D, Zagray JA
JournalZygote
PubMed ID8730895
The intracellular pH of the mouse egg was measured during fertilisation to determine whether an increase in pH accompanies activation of this mammalian egg. The pH-sensitive dye BCECF [2',7'-bis-(2-carboxyethyl)-5(and-6)carboxyfluorescein] was introduced into the mouse egg by incubation in BCECF-AM or by microinjection of dextran-conjugated BCECF. The cells were also loaded ... More
Polarized expression and function of P2Y ATP receptors in rat bile duct epithelia.
Extracellular nucleotides may be important regulators of bile ductular secretion, because cholangiocytes express P2Y ATP receptors and nucleotides are found in bile. However, the expression, distribution, and function of specific P2Y receptor subtypes in cholangiocytes are unknown. Thus our aim was to determine the subtypes, distribution, and role in secretion ... More
Perfused rat intrahepatic bile ducts secrete and absorb water, solute, and ions.
AuthorsMasyuk AI, Gong AY, Kip S, Burke MJ, LaRusso NF
JournalGastroenterology
PubMed ID11113089
BACKGROUND & AIMS: We report a novel approach to study biliary water, bile acid, and HCO(3)(-) transport: the microperfusion of intrahepatic bile duct units (IBDUs) isolated from normal rat liver. METHODS: To study water transport, IBDUs were perfused in vitro with a membrane-impermeant fluorescent volume marker, fluorescein sulfonate; net water ... More
An increase in intracellular pH during neural induction in Xenopus.
AuthorsSater AK, Alderton JM, Steinhardt RA
JournalDevelopment
PubMed ID8149919
In this paper, we show that an intracellular alkalinization of the dorsal ectoderm cells is among the earliest responses to neural induction in Xenopus. Planar explants of the dorsal marginal zone were prepared from embryos that had been microinjected during cleavage stages with the fluorescent pH indicator bis-carboxyethyl-carboxyfluorescein-dextran (BCECF-dextran), and ... More
Submucosal gland secretions in airways from cystic fibrosis patients have normal [Na(+)] and pH but elevated viscosity.
AuthorsJayaraman S, Joo NS, Reitz B, Wine JJ, Verkman AS
JournalProc Natl Acad Sci U S A
PubMed ID11427704
Fluid and macromolecule secretion by submucosal glands in mammalian airways is believed to be important in normal airway physiology and in the pathophysiology of cystic fibrosis (CF). An in situ fluorescence method was applied to measure the ionic composition and viscosity of freshly secreted fluid from airway glands. Fragments of ... More
Airway surface liquid pH in well-differentiated airway epithelial cell cultures and mouse trachea.
AuthorsJayaraman S, Song Y, Verkman AS
JournalAm J Physiol Cell Physiol
PubMed ID11600413
Airway surface liquid (ASL) pH has been proposed to be important in the pathophysiology of cystic fibrosis, asthma, and cough. Ratio image analysis was used to measure pH in the ASL after staining with the fluorescent pH indicator 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF)-dextran. ASL pH in bovine airway cell cultures grown at an ... More
The adenine nucleotide translocase modulates oligomycin-induced quenching of pyranine fluorescence in submitochondrial particles.
AuthorsZiegler M, Penefsky HS
JournalJ Biol Chem
PubMed ID8244963
Incorporation of the fluorescent, nonpermeant pH indicator pyranine into submitochondrial particles (pyranine-SMP) permitted monitoring of intravesicular pH changes brought about by proton translocation due to oxidation of respiratory chain substrates or to hydrolysis of ATP. Addition of oligomycin to beef heart pyranine-SMP was followed by a pH-independent quenching of pyranine ... More
Identification of PLCgamma-dependent and -independent events during fertilization of sea urchin eggs.
AuthorsCarroll DJ, Albay DT, Terasaki M, Jaffe LA, Foltz KR
JournalDev Biol
PubMed ID9986735
At fertilization, sea urchin eggs undergo a series of activation events, including a Ca2+ action potential, Ca2+ release from the endoplasmic reticulum, an increase in intracellular pH, sperm pronuclear formation, MAP kinase dephosphorylation, and DNA synthesis. To examine which of these events might be initiated by activation of phospholipase Cgamma ... More
The intracellular calcium increase at fertilization in Urechis caupo oocytes: activation without waves.
AuthorsStephano JL, Gould MC
JournalDev Biol
PubMed ID9356171
The intracellular Ca2+ (Cai) increase at fertilization of the marine worm Urechis caupo (Echiura) was studied with conventional and confocal epifluorescence microscopy in oocytes microinjected with calcium green dextran or dually labeled with the calcium-insensitive dye tetramethylrhodamine dextran. Calcium green fluorescence was also measured with a photomultiplier system while the ... More
Regulation of bicarbonate-dependent ductular bile secretion assessed by lumenal micropuncture of isolated rodent intrahepatic bile ducts.
AuthorsRoberts SK, Kuntz SM, Gores GJ, LaRusso NF
JournalProc Natl Acad Sci U S A
PubMed ID8415657
While intrahepatic bile duct epithelial cells secrete bile through transport of ions and water, the physiological mechanisms regulating ductular bile secretion are obscure, in part because of the lack of suitable experimental models. We report here the successful micropuncture of the lumen of isolated intrahepatic bile ducts and direct measurements ... More