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  1. Article ; Online: Mitochondrial leak metabolism induces the Spemann-Mangold Organizer via Hif-1α in Xenopus.

    MacColl Garfinkel, Alexandra / Mnatsakanyan, Nelli / Patel, Jeet H / Wills, Andrea E / Shteyman, Amy / Smith, Peter J S / Alavian, Kambiz N / Jonas, Elizabeth Ann / Khokha, Mustafa K

    Developmental cell

    2023  Volume 58, Issue 22, Page(s) 2597–2613.e4

    Abstract: An instructive role for metabolism in embryonic patterning is emerging, although a role for mitochondria is poorly defined. We demonstrate that mitochondrial oxidative metabolism establishes the embryonic patterning center, the Spemann-Mangold Organizer, ...

    Abstract An instructive role for metabolism in embryonic patterning is emerging, although a role for mitochondria is poorly defined. We demonstrate that mitochondrial oxidative metabolism establishes the embryonic patterning center, the Spemann-Mangold Organizer, via hypoxia-inducible factor 1α (Hif-1α) in Xenopus. Hypoxia or decoupling ATP production from oxygen consumption expands the Organizer by activating Hif-1α. In addition, oxygen consumption is 20% higher in the Organizer than in the ventral mesoderm, indicating an elevation in mitochondrial respiration. To reconcile increased mitochondrial respiration with activation of Hif-1α, we discovered that the "free" c-subunit ring of the F
    MeSH term(s) Animals ; Adenosine Triphosphate/metabolism ; Hypoxia ; Hypoxia-Inducible Factor 1, alpha Subunit ; Mitochondria/metabolism ; Organizers, Embryonic/metabolism ; Xenopus laevis
    Chemical Substances Adenosine Triphosphate (8L70Q75FXE) ; Hypoxia-Inducible Factor 1, alpha Subunit
    Language English
    Publishing date 2023-09-05
    Publishing country United States
    Document type Journal Article
    ZDB-ID 2054967-2
    ISSN 1878-1551 ; 1534-5807
    ISSN (online) 1878-1551
    ISSN 1534-5807
    DOI 10.1016/j.devcel.2023.08.015
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article: Review and Hypothesis: A Potential Common Link Between Glial Cells, Calcium Changes, Modulation of Synaptic Transmission, Spreading Depression, Migraine, and Epilepsy-H

    Malchow, Robert Paul / Tchernookova, Boriana K / Choi, Ji-In Vivien / Smith, Peter J S / Kramer, Richard H / Kreitzer, Matthew A

    Frontiers in cellular neuroscience

    2021  Volume 15, Page(s) 693095

    Abstract: There is significant evidence to support the notion that glial cells can modulate the strength of synaptic connections between nerve cells, and it has further been suggested that alterations in intracellular calcium are likely to play a key role in this ... ...

    Abstract There is significant evidence to support the notion that glial cells can modulate the strength of synaptic connections between nerve cells, and it has further been suggested that alterations in intracellular calcium are likely to play a key role in this process. However, the molecular mechanism(s) by which glial cells modulate neuronal signaling remains contentiously debated. Recent experiments have suggested that alterations in extracellular H
    Language English
    Publishing date 2021-09-03
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2452963-1
    ISSN 1662-5102
    ISSN 1662-5102
    DOI 10.3389/fncel.2021.693095
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Using Pharmabase to perform pharmacological analyses of cell function.

    Smith, Peter J S / Remsen, David

    Current protocols in bioinformatics

    2008  Volume Chapter 14, Page(s) 14.2.1–14.2.17

    Abstract: Pharmabase is designed to form a bridge between the molecular dimension of cell transport processes and the functional manipulation of the protein players. It has as its emphasis membrane transport and related pharmacology. Several search and navigation ... ...

    Abstract Pharmabase is designed to form a bridge between the molecular dimension of cell transport processes and the functional manipulation of the protein players. It has as its emphasis membrane transport and related pharmacology. Several search and navigation options are available, including membrane transport, disease, and a graphic interface arranged by pathway and cell type. The level of entry to the database can be tailored to the investigator's level of expertise. The final product of Pharmabase is a Compound Record detailing the use and targets of individual compounds. Navigation routes generally fall into hierarchical keys and are cross-referenced. Pharmabase encourages input from its user community. It is maintained by the BioCurrents Research Center, an NIH resource funded through the National Center for Research Resources (NCRR).
    MeSH term(s) Cell Physiological Phenomena ; Database Management Systems ; Databases, Factual ; Drug Delivery Systems/methods ; Information Storage and Retrieval/methods ; Pharmaceutical Preparations/administration & dosage ; User-Computer Interface
    Chemical Substances Pharmaceutical Preparations
    Language English
    Publishing date 2008-04-21
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 2179022-X
    ISSN 1934-340X ; 1934-3396
    ISSN (online) 1934-340X
    ISSN 1934-3396
    DOI 10.1002/0471250953.bi1402s13
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article: Rhythm of the beta-cell oscillator is not governed by a single regulator: multiple systems contribute to oscillatory behavior.

    Heart, Emma / Smith, Peter J S

    American journal of physiology. Endocrinology and metabolism

    2007  Volume 292, Issue 5, Page(s) E1295–300

    Abstract: Pulsatile insulin output, paralleled by oscillations in intracellular Ca(2+), reflect oscillating metabolism within beta-cells in response to secretory fuels. Here we question whether oscillatory periodicity is conserved or varied from stimulation to ... ...

    Abstract Pulsatile insulin output, paralleled by oscillations in intracellular Ca(2+), reflect oscillating metabolism within beta-cells in response to secretory fuels. Here we question whether oscillatory periodicity is conserved or varied from stimulation to stimulation, whether glycolysis is essential for the manifestation of an oscillatory response, and if an environment of nutrient oversupply affects oscillatory regularity. We have determined that a beta-cell oscillatory Ca(2+) pattern is independent of the type of applied secretory fuel (glucose, methyl-pyruvate, or alpha-ketoisocaproate). In addition, single cells respond with the same pattern when repeatedly stimulated, regardless of the type of stimulatory fuel. Presence of substimulatory glucose is not necessary to obtain an oscillatory responses to methyl-pyruvate or alpha-ketoisocaproate. Glucose-6-phosphate, as a measure of glycolytic flux, is not detectable under these conditions. These data suggest that multiple systems, rather than a single enzyme component, can contribute to the beta-cell oscillatory behavior. Prolonged exposure to high levels of palmitate impaired oscillatory regularity in the individual beta-cells. This supports the hypothesis that a high-fat environment might contribute to loss of regular oscillatory pattern in diabetic subjects, acting, at least in part, at the level of the single beta-cell.
    MeSH term(s) Animals ; Biological Clocks/drug effects ; Biological Clocks/physiology ; Calcium/metabolism ; Glucose/pharmacology ; Glucose-6-Phosphate/metabolism ; In Vitro Techniques ; Insulin/metabolism ; Insulin Secretion ; Insulin-Secreting Cells/drug effects ; Insulin-Secreting Cells/metabolism ; Insulin-Secreting Cells/physiology ; Keto Acids/pharmacology ; Male ; Mice ; Microscopy, Confocal ; Palmitates/pharmacology ; Pyruvates/pharmacology
    Chemical Substances Insulin ; Keto Acids ; Palmitates ; Pyruvates ; methyl pyruvate (3KJM65G5XL) ; Glucose-6-Phosphate (56-73-5) ; alpha-ketoisocaproic acid (816-66-0) ; Glucose (IY9XDZ35W2) ; Calcium (SY7Q814VUP)
    Language English
    Publishing date 2007-01-09
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 603841-4
    ISSN 1522-1555 ; 0193-1849
    ISSN (online) 1522-1555
    ISSN 0193-1849
    DOI 10.1152/ajpendo.00648.2006
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article: Construction, theory, and practical considerations for using self-referencing of Ca(2+)-selective microelectrodes for monitoring extracellular Ca(2+) gradients.

    Messerli, Mark A / Smith, Peter J S

    Methods in cell biology

    2010  Volume 99, Page(s) 91–111

    Abstract: Ca(2+) signaling in the extra- and intracellular domains is linked to Ca(2+) transport across the plasma membrane. Noninvasive monitoring of these resulting extracellular Ca(2+) gradients with self-referencing of Ca(2+)-selective microelectrodes is used ... ...

    Abstract Ca(2+) signaling in the extra- and intracellular domains is linked to Ca(2+) transport across the plasma membrane. Noninvasive monitoring of these resulting extracellular Ca(2+) gradients with self-referencing of Ca(2+)-selective microelectrodes is used for studying Ca(2+) signaling across Kingdoms. The quantitated Ca(2+) flux enables comparison with changes to intracellular [Ca(2+)] measured with other methods and determination of Ca(2+) transport stoichiometry. Here, we review the construction of Ca(2+)-selective microelectrodes, their physical characteristics, and their use in self-referencing mode to calculate Ca(2+) flux. We also discuss potential complications when using them to measure Ca(2+) gradients near the boundary layers of single cells and tissues.
    MeSH term(s) Animals ; Artifacts ; Buffers ; Calcium/metabolism ; Electrochemical Techniques/instrumentation ; Electrochemical Techniques/methods ; Extracellular Space/metabolism ; Ion-Selective Electrodes ; Mice ; Microelectrodes ; Time Factors
    Chemical Substances Buffers ; Calcium (SY7Q814VUP)
    Language English
    Publishing date 2010
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ISSN 0091-679X
    ISSN 0091-679X
    DOI 10.1016/B978-0-12-374841-6.00004-9
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article ; Online: Windows to cell function and dysfunction: signatures written in the boundary layers.

    Smith, Peter J S / Collis, Leon P / Messerli, Mark A

    BioEssays : news and reviews in molecular, cellular and developmental biology

    2010  Volume 32, Issue 6, Page(s) 514–523

    Abstract: The medium surrounding cells either in culture or in tissues contains a chemical mix varying with cell state. As solutes move in and out of the cytoplasmic compartment they set up characteristic signatures in the cellular boundary layers. These layers ... ...

    Abstract The medium surrounding cells either in culture or in tissues contains a chemical mix varying with cell state. As solutes move in and out of the cytoplasmic compartment they set up characteristic signatures in the cellular boundary layers. These layers are complex physical and chemical environments the profiles of which reflect cell physiology and provide conduits for intercellular messaging. Here we review some of the most relevant characteristics of the extracellular/intercellular space. Our initial focus is primarily on cultured cells but we extend our consideration to the far more complex environment of tissues, and discuss how chemical signatures in the boundary layer can or may affect cell function. Critical to the entire essay are the methods used, or being developed, to monitor chemical profiles in the boundary layers. We review recent developments in ultramicro electrochemical sensors and tailored optical reporters suitable for the task in hand.
    MeSH term(s) Cell Physiological Phenomena/physiology ; Cells, Cultured ; Extracellular Space/metabolism ; Models, Biological
    Language English
    Publishing date 2010-06
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural ; Review
    ZDB-ID 50140-2
    ISSN 1521-1878 ; 0265-9247
    ISSN (online) 1521-1878
    ISSN 0265-9247
    DOI 10.1002/bies.200900173
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  7. Article ; Online: Ion trapping with fast-response ion-selective microelectrodes enhances detection of extracellular ion channel gradients.

    Messerli, Mark A / Collis, Leon P / Smith, Peter J S

    Biophysical journal

    2009  Volume 96, Issue 4, Page(s) 1597–1605

    Abstract: Previously, functional mapping of channels has been achieved by measuring the passage of net charge and of specific ions with electrophysiological and intracellular fluorescence imaging techniques. However, functional mapping of ion channels using ... ...

    Abstract Previously, functional mapping of channels has been achieved by measuring the passage of net charge and of specific ions with electrophysiological and intracellular fluorescence imaging techniques. However, functional mapping of ion channels using extracellular ion-selective microelectrodes has distinct advantages over the former methods. We have developed this method through measurement of extracellular K+ gradients caused by efflux through Ca2+-activated K+ channels expressed in Chinese hamster ovary cells. We report that electrodes constructed with short columns of a mechanically stable K+-selective liquid membrane respond quickly and measure changes in local [K+] consistent with a diffusion model. When used in close proximity to the plasma membrane (<4 microm), the ISMs pose a barrier to simple diffusion, creating an ion trap. The ion trap amplifies the local change in [K+] without dramatically changing the rise or fall time of the [K+] profile. Measurement of extracellular K+ gradients from activated rSlo channels shows that rapid events, 10-55 ms, can be characterized. This method provides a noninvasive means for functional mapping of channel location and density as well as for characterizing the properties of ion channels in the plasma membrane.
    MeSH term(s) Animals ; CHO Cells ; Cell Membrane/physiology ; Computer Simulation ; Cricetinae ; Cricetulus ; Diffusion ; Extracellular Space/chemistry ; Ion Channel Gating/physiology ; Microelectrodes ; Monte Carlo Method ; Patch-Clamp Techniques ; Potassium/analysis ; Potassium/metabolism ; Potassium Channels, Calcium-Activated/physiology
    Chemical Substances Potassium Channels, Calcium-Activated ; Potassium (RWP5GA015D)
    Language English
    Publishing date 2009-01-06
    Publishing country United States
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 218078-9
    ISSN 1542-0086 ; 0006-3495
    ISSN (online) 1542-0086
    ISSN 0006-3495
    DOI 10.1016/j.bpj.2008.11.025
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article: The level of menadione redox-cycling in pancreatic β-cells is proportional to the glucose concentration: Role of NADH and consequences for insulin secretion

    Heart, Emma / Palo, Meridith / Womack, Trayce / Smith, Peter J.S / Gray, Joshua P

    Toxicology and applied pharmacology. 2012 Jan. 15, v. 258, no. 2

    2012  

    Abstract: Pancreatic β-cells release insulin in response to elevation of glucose from basal (4–7mM) to stimulatory (8–16mM) levels. Metabolism of glucose by the β-cell results in the production of low levels of reactive oxygen intermediates (ROI), such as hydrogen ...

    Abstract Pancreatic β-cells release insulin in response to elevation of glucose from basal (4–7mM) to stimulatory (8–16mM) levels. Metabolism of glucose by the β-cell results in the production of low levels of reactive oxygen intermediates (ROI), such as hydrogen peroxide (H2O2), a newly recognized coupling factor linking glucose metabolism to insulin secretion. However, high and toxic levels of H2O2 inhibit insulin secretion. Menadione, which produces H2O2 via redox cycling mechanism in a dose-dependent manner, was investigated for its effect on β-cell metabolism and insulin secretion in INS-1 832/13, a rat β-cell insulinoma cell line, and primary rodent islets. Menadione-dependent redox cycling and resulting H2O2 production under stimulatory glucose exceeded several-fold those reached at basal glucose. This was paralleled by a differential effect of menadione (0.1–10μM) on insulin secretion, which was enhanced at basal, but inhibited at stimulatory glucose. Redox cycling of menadione and H2O2 formation was dependent on glycolytically-derived NADH, as inhibition of glycolysis and application of non-glycogenic insulin secretagogues did not support redox cycling. In addition, activity of plasma membrane electron transport, a system dependent in part on glycolytically-derived NADH, was also inhibited by menadione. Menadione-dependent redox cycling was sensitive to the NQO1 inhibitor dicoumarol and the flavoprotein inhibitor diphenylene iodonium, suggesting a role for NQO1 and other oxidoreductases in this process. These data may explain the apparent dichotomy between the stimulatory and inhibitory effects of H2O2 and menadione on insulin secretion.
    Keywords NAD (coenzyme) ; dicoumarol ; dose response ; electron transfer ; flavoproteins ; glucose ; glycolysis ; hydrogen peroxide ; insulin ; insulin secretion ; islets of Langerhans ; menadione ; oxidoreductases ; plasma membrane ; rats ; toxicity
    Language English
    Dates of publication 2012-0115
    Size p. 216-225.
    Publishing place Elsevier Inc.
    Document type Article
    ZDB-ID 204477-8
    ISSN 1096-0333 ; 0041-008X
    ISSN (online) 1096-0333
    ISSN 0041-008X
    DOI 10.1016/j.taap.2011.11.002
    Database NAL-Catalogue (AGRICOLA)

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  9. Article ; Online: Characterization of optimized Na+ and Cl- liquid membranes for use with extracellular, self-referencing microelectrodes.

    Messerli, Mark A / Kurtz, Ira / Smith, Peter J S

    Analytical and bioanalytical chemistry

    2008  Volume 390, Issue 5, Page(s) 1355–1359

    Abstract: Self-referencing with ion-selective microelectrodes (ISMs) is a useful approach for monitoring near-real-time ion flux near single cells and across epithelia. While ISMs for H+, Ca2+, and K+ have been optimized for use with self-referencing, ISMs for two ...

    Abstract Self-referencing with ion-selective microelectrodes (ISMs) is a useful approach for monitoring near-real-time ion flux near single cells and across epithelia. While ISMs for H+, Ca2+, and K+ have been optimized for use with self-referencing, ISMs for two other primary inorganic ions, Na+ and Cl-, have not. In this study, we have characterized ISMs based on three Na+ ionophores (I, VI, and X) and one Cl- ionophore to assess their suitability for use with self-referencing. ISMs constructed with Na+ ionophore VI have short response times (approximately 100 ms) but possess nearly an order of magnitude less selectivity for Na+ over K+ than ISMs constructed with Na+ ionophore X. The Na+ ionophore X mixture was enhanced to give it a shorter response time while not compromising its selectivity. A Cl(-)-selective microelectrode was constructed and characterized with superior anionic selectivity compared with previously reported Cl- ISMs used with self-referencing. This Cl(-)-selective microelectrode, however, has a relatively slow response time (approximately 3 s), thus requiring changes to the self-referencing protocol. Self-referencing with these ISMs will enable near-real-time ion flux measurements for Na+ and Cl-.
    MeSH term(s) Chlorides/chemistry ; Ions/chemistry ; Microelectrodes ; Sodium/chemistry ; Sodium Chloride Symporter Inhibitors/pharmacology
    Chemical Substances Chlorides ; Ions ; Sodium Chloride Symporter Inhibitors ; Sodium (9NEZ333N27)
    Language English
    Publishing date 2008-03
    Publishing country Germany
    Document type Journal Article ; Research Support, N.I.H., Extramural
    ZDB-ID 201093-8
    ISSN 1618-2650 ; 0016-1152 ; 0372-7920
    ISSN (online) 1618-2650
    ISSN 0016-1152 ; 0372-7920
    DOI 10.1007/s00216-007-1804-z
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article: Measuring extracellular ion gradients from single channels with ion-selective microelectrodes.

    Messerli, Mark A / Corson, Erica D / Smith, Peter J S

    Biophysical journal

    2007  Volume 92, Issue 7, Page(s) L52–4

    Abstract: Under many different conditions activated plasma membrane ion channels give rise to changes in the extracellular concentration of the permeant ion(s). The magnitude and duration of these changes are dependent on the electrochemical driving force(s) on ... ...

    Abstract Under many different conditions activated plasma membrane ion channels give rise to changes in the extracellular concentration of the permeant ion(s). The magnitude and duration of these changes are dependent on the electrochemical driving force(s) on the permeant ion(s) as well as conductance, open time, and channel density. We have modeled the change in the extracellular [K+] due to efflux through Ca2+-activated K+ channels, mSlo, to determine the range of parameters that would give rise to measurable signals in the surrounding media. Subsequently we have used extracellular, K+-selective microelectrodes to monitor localized changes in [K+]ext due to efflux through mSlo channels expressed in Xenopus oocytes. The rapid changes in [K+] show a close fit with the predicted model when the time response of the ion-selective microelectrode is taken into account, providing proof of the concept. Measurement of the change in extracellular ion concentration with ion-selective microelectrodes provides a noninvasive means for functional mapping of channel location and density, as well as characterizing the properties of ion channels in the plasma membrane.
    MeSH term(s) Animals ; Cells, Cultured ; Extracellular Fluid/metabolism ; Ion Channel Gating/physiology ; Ions ; Large-Conductance Calcium-Activated Potassium Channel alpha Subunits/physiology ; Microelectrodes ; Oocytes/physiology ; Patch-Clamp Techniques/instrumentation ; Patch-Clamp Techniques/methods ; Sensitivity and Specificity ; Xenopus laevis
    Chemical Substances Ions ; Kcnma1 protein, mouse ; Large-Conductance Calcium-Activated Potassium Channel alpha Subunits
    Language English
    Publishing date 2007-04-01
    Publishing country United States
    Document type Letter ; Research Support, N.I.H., Extramural
    ZDB-ID 218078-9
    ISSN 1542-0086 ; 0006-3495
    ISSN (online) 1542-0086
    ISSN 0006-3495
    DOI 10.1529/biophysj.106.102947
    Database MEDical Literature Analysis and Retrieval System OnLINE

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