The two intracellular Ca2+ release channels, ryanodine receptor and inositol 1,4,5-trisphosphate receptor, play different roles during fertilization in ascidians.
AuthorsAlbrieux M, Sardet C, Villaz M
JournalDev Biol
PubMed ID9299112
'Fertilization in the ascidians triggers an activation wave of calcium release followed by intracellular calcium oscillations synchronous with periodic membrane potential excursions during the completion of the meiotic cell cycle. Fertilization also causes a fast decrease in the egg plasma membrane depolarization-activated calcium current and a large increase in capacitance ... More
Re-evaluation of phorbol ester-induced potentiation of transmitter release from mossy fibre terminals of the mouse hippocampus.
AuthorsHonda I, Kamiya H, Yawo H
JournalJ Physiol
PubMed ID11118504
'To investigate the mechanisms by which phorbol esters potentiate transmitter release from mossy fibre terminals we used fura dextran to measure the intraterminal Ca2+ concentration in mouse hippocampal slices. A phorbol ester, phorbol 12,13-diacetate (PDAc), potentiated the field excitatory postsynaptic potential (fEPSP) slope. PDAc also enhanced the stimulation-dependent increase of ... More
Plant calcium signaling and monitoring: pros and cons and recent experimental approaches.
AuthorsPlieth C
JournalProtoplasma
PubMed ID11732314
'This review focusses on Ca(2+)-mediated plant cell signaling and optical methods for in vivo [Ca2+] monitoring and imaging in plants. The cytosolic free calcium concentration has long been considered the central cellular key in plants. However, more and more data are turning up that critically question this view. Conflicting arguments ... More
Elemental propagation of calcium signals in response-specific patterns determined by environmental stimulus strength.
AuthorsGoddard H, Manison NF, Tomos D, Brownlee C
JournalProc Natl Acad Sci U S A
PubMed ID10677557
'Plant cells can respond qualitatively and quantitatively to a wide range of environmental signals. Ca(2+) is used as an intracellular signal for volume regulation in response to external osmotic changes. We show here that the spatiotemporal patterns of hypo-osmotically induced Ca(2+) signals vary dramatically with stimulus strength in embryonic cells ... More
Rhizobium nod factors induce increases in intracellular free calcium and extracellular calcium influxes in bean root hairs
AuthorsCardenas L, Feijo JA, Kunkel JG, Sanchez F, Holdaway-Clarke T, Hepler PK, Quinto C
JournalPlant J
PubMed ID10476081
'Application of Nod factors to growing, responsive root hairs of the bean Phaseolus vulgaris induces marked changes in both the intracellular cytosolic free calcium (Ca2+) and in the influx of extracellular [Ca2+]. The intracellular [Ca2+], which has been measured by ratiometric imaging in cells microinjected with fura-2-dextran (70 kDa), elevates ... More
Patterns of intracellular Ca2+ concentrations in fertilized bovine eggs.
AuthorsFissore RA, Dobrinsky JR, Balise JJ, Duby RT, Robl JM
JournalBiol Reprod
PubMed ID1493184
'Sperm-induced calcium (Ca2+) changes were examined in zona pellucida-intact, mature bovine eggs injected with the fluorescent Ca2+ indicator fura-2 dextran (fura-2 D). Fifty four percent (37/68) of the dye-injected, inseminated bovine eggs were fertilized and 43% (16/37) of the fertilized eggs exhibited Ca2+ elevations during the time of measurement. All ... More
Free calcium in Micrasterias: local gradients are not detected in growing lobes.
AuthorsHolzinger A, Callaham DA, Hepler PK, Meindl U
JournalEur J Cell Biol
PubMed ID8521876
'Intracellular free Ca2+ ([Ca2+]) has been measured in growing unicells of two species of the green alga, Micrasterias, which have been injected with the indicator dye fura-2-dextran. Ratiometric imaging of Micrasterias denticulata yields levels of 170 to 200 nM [Ca2+] but fails to reveal a significant [Ca2+] gradient associated with ... More
Intracellular calcium during chemotaxis of Dictyostelium discoideum: a new fura-2 derivative avoids sequestration of the indicator and allows long-term calcium measurements.
AuthorsSchlatterer C, Knoll G, Malchow D
JournalEur J Cell Biol
PubMed ID1322818
'During stimulation of Dictyostelium discoideum amoebae with the chemoattractant cAMP, extracellular calcium is taken up by the cells. The aim of this study was to determine the cytosolic free calcium concentration ([Ca++]i) during chemotaxis of Dictyostelium cells. In contrast to most vertebrate cells, three major drawbacks were encountered: 1) the ... More
Atrial natriuretic peptide attenuates Ca2+ oscillations and modulates plasma membrane Ca2+ fluxes in rat hepatocytes.
AuthorsGreen AK, Zolle O, Simpson AW
JournalGastroenterology
PubMed ID12360489
'Background & Aims: Oscillations in cytosolic free Ca2+ concentration are a fundamental mechanism of intracellular signaling in hepatocytes. The aim of this study was to examine the effects of atrial natriuretic peptide (ANP) on cytosolic Ca2+ oscillations in rat hepatocytes. METHODS: Cyclic guanosine monophosphate (cGMP) was measured by enzyme immunoassay. ... More
Maitotoxin-induced free Ca changes in single rat hepatocytes.
'We report the results using bioluminescent and fluorescent indicators to investigate maitotoxin-induced free Ca changes in single rat hepatocytes. Maitotoxin generated a steadily rising free Ca increase after a long lag period. The free Ca increase was dependent on extracellular calcium and could be antagonised by chelation of extracellular calcium ... More
An increase in [Ca2+]i is sufficient but not necessary for driving mitosis in early mouse embryos.
AuthorsFitzHarris G, Larman M, Richards C, Carroll J
JournalJ Cell Sci
PubMed ID16179613
'An increase in intracellular Ca2+ concentration ([Ca2+]i) has been shown to drive sea-urchin embryos and some fibroblasts through nuclear-envelope breakdown (NEBD) and the metaphase-to-anaphase transition. Mitotic Ca2+ transients can be pan-cellular global events or localized to the perinuclear region. It is not known whether Ca2+ is a universal regulator of ... More
Sperm, inositol trisphosphate, and thimerosal-induced intracellular Ca2+ elevations in rabbit eggs.
AuthorsFissore RA, Robl JM
JournalDev Biol
PubMed ID8365556
'Fertilization-induced calcium (Ca2+) changes were examined in in vivo fertilized rabbit eggs, using the fluorescent Ca2+ inducer fura-2 dextran. Twenty-four of 48 fertilized eggs exhibited repetitive Ca2+ rises with intervals of 13 +/- 1 min (mean +/- SEM) during the recording period of 45 min. None of the unfertilized eggs ... More
Real-time imaging of neurons retrogradely and anterogradely labelled with calcium-sensitive dyes.
AuthorsO'Donovan MJ, Ho S, Sholomenko G, Yee W
JournalJ Neurosci Methods
PubMed ID8474261
'Membrane-impermeant calcium indicator dyes were used to retrogradely label dorsal root ganglia, spinal motoneurons and interneurons in the spinal cord of the chick embryo. The dyes were also used to label anterogradely primary afferent axons in the spinal cord and synaptic endings in the ciliary ganglion. Labelled neurons were imaged ... More
Local positive feedback by calcium in the propagation of intracellular calcium waves.
AuthorsWang SS, Thompson SH
JournalBiophys J
PubMed ID8580312
'In many types of eukaryotic cells, the activation of surface receptors leads to the production of inositol 1,4,5-trisphosphate and calcium release from intracellular stores. Calcium release can occur in complex spatial patterns, including waves of release that traverse the cytoplasm. Fluorescence video microscopy was used to view calcium waves in ... More
Electric field-directed fibroblast locomotion involves cell surface molecular reorganization and is calcium independent.
AuthorsBrown MJ, Loew LM
JournalJ Cell Biol
PubMed ID7929557
'Directional cellular locomotion is thought to involve localized intracellular calcium changes and the lateral transport of cell surface molecules. We have examined the roles of both calcium and cell surface glycoprotein redistribution in the directional migration of two murine fibroblastic cell lines, NIH 3T3 and SV101. These cell types exhibit ... More
[Effect of heparin on the increase in intracellular calcium caused by inositol 1,4,5-triphosphate in airway epithelial cells]
AuthorsKondo M, Tamaoki J, Isono K, Kanoh S, Konno K
JournalNihon Kyobu Shikkan Gakkai Zasshi
PubMed ID9103854
'We studied the effect of heparin on the inositol 1,4,5-triphosphate (IP3)-dependent increase in intracellular calcium (Ca2+) caused by ATP. The Ca2+ concentration ([Ca2+]i) in cultured epithelial cells from cow tracheas was measured by the fura-2 method. ATP (10(-4) M) stimulated IP3 production and caused a biphasic increase in [Ca2+]i a ... More
Cell-cycle calcium transients driven by cyclic changes in inositol trisphosphate levels.
AuthorsCiapa B, Pesando D, Wilding M, Whitaker M
JournalNature
PubMed ID8159248
'Transient changes in intracellular calcium ([Ca2+]i) have been shown to punctuate the cell cycle in various types of cells in culture and in early embryos. The [Ca2+]i transients are correlated with cell-cycle events: pronuclear migration, nuclear envelope breakdown, the metaphase-anaphase transition of mitosis, and cytokinesis. Mitotic events can be induced ... More
A Xestospongin C-sensitive Ca(2+) store is required for cAMP-induced Ca(2+) influx and cAMP oscillations in Dictyostelium.
AuthorsSchaloske R, Schlatterer C, Malchow D
JournalJ Biol Chem
PubMed ID10722673
'Xestospongin C (XeC) is known to bind to the inositol 1,4, 5-trisphosphate (IP(3))-sensitive store in mammalian cells and to inhibit IP(3)- and thapsigargin-induced Ca(2+) release. In this study we show that this is also true for Dictyostelium. In addition, XeC inhibited Ca(2+) uptake into purified vesicle fractions and induced Ca(2+) ... More
Inactivation of histone H1 kinase by Ca2+ in rabbit oocytes.
AuthorsCollas P, Chang T, Long C, Robl JM
JournalMol Reprod Dev
PubMed ID7766419
'The present study investigated the role of intracellular Ca2+ (Ca2+i) elevation on the inactivation of maturation promoting factor (MPF) in rabbit oocytes. The effects of the number of Ca2+ stimulations and of the amplitude of Ca2+i elevation on the profile of histone H1 kinase activity were determined. A Ca2+ stimulation ... More
Calcium mobilization is required for nuclear vesicle fusion in vitro: implications for membrane traffic and IP3 receptor function.
AuthorsSullivan KM, Busa WB, Wilson KL
JournalCell
PubMed ID8391933
'We studied the fusion of nuclear vesicles bound to chromatin in Xenopus egg extracts. Fusion was inhibited by 5 mM BAPTA, a Ca2+ buffer that suppresses cytosolic [Ca2+] gradients. The BAPTA-inhibited step in fusion was biochemically distinct from, and occurred later than, the GTP gamma S-sensitive step mediated by the ... More
Independent modes of propagation of calcium waves in smooth muscle cells.
AuthorsMahoney MG, Slakey LL, Hepler PK, Gross DJ
JournalJ Cell Sci
PubMed ID8314894
The purinergic agonist adenosine triphosphate (ATP) stimulates an initial transient followed by subsequent oscillations in cytosolic calcium ion concentration ([Ca2+]i) in individual porcine aortic smooth muscle cells. Using microinjection of fura-2 covalently coupled to dextran, we have analyzed in detail the spatial and temporal features of the oscillations. We have ... More
Pollen Tube Growth and the Intracellular Cytosolic Calcium Gradient Oscillate in Phase while Extracellular Calcium Influx Is Delayed.
'Ratio images of cytosolic Ca2+ (Ca2+i) in growing, fura-2-dextran-loaded Lilium longiflorum pollen tubes taken at 3- to 5-sec intervals showed that the tip-focused [Ca2+]i gradient oscillates with the same period as growth. Similarly, measurement of the extracellular inward current, using a noninvasive ion-selective vibrating probe, indicated that the tip-directed extracellular ... More
Preferential inhibition of omega-conotoxin-sensitive presynaptic Ca2+ channels by adenosine autoreceptors.
AuthorsYawo H, Chuhma N
JournalNature
PubMed ID8396730
'Adenosine is a potent modulator of transmitter release at a variety of synapses. The adenosine A1 receptor is assumed to reside in presynaptic terminals and to function as a negative autoreceptor. How adenosine reduces transmitter release is uncertain; it may reduce the calcium influx during nerve terminal depolarization by either ... More
Uncoupling secretion and tip growth in lily pollen tubes: evidence for the role of calcium in exocytosis
'Cytoplasmic calcium concentration ([Ca2+]i) and extracellular calcium (Ca2+o) influx has been studied in pollen tubes of Lilium longliflorum in which the processes of cell elongation and exocytosis have been uncoupled by use of Yariv phenylglycoside ((beta-D-Glc)3). Growing pollen tubes were pressure injected with the ratio dye fura-2 dextran and imaged ... More
Assessment and validation of a microinjection method for kinetic analysis of [Ca2+]i in individual cells undergoing apoptosis.
AuthorsTombal B, Denmeade SR, Isaacs JT
JournalCell Calcium
PubMed ID10191957
'Normal and malignant epithelial cells are induced to undergo apoptosis by a large variety of mechanistically diverse agents. Regardless of inducing agent, apoptosis characteristically occurs asynchronously within a population of epithelial cells over a period of 12-96 h and is associated with permeability and enzymatic perturbations. Pre-loading of cells with ... More
Inositol-phosphoglycan inhibits calcium oscillations in hepatocytes by reducing calcium entry.
AuthorsSanchez-Bueno A, Greenwood MR, Varela-Nieto I, Marrero I, Gil B, Mato JM, Cobbold PH
JournalCell Calcium
PubMed ID9132295
'Inositol-phosphoglycan (IPG) is a putative mediator of insulin action that has been shown to affect numerous biochemical processes. IPG, prepared from liver membranes, promptly inhibited phenylephrine- or vasopressin-induced [Ca2+]i oscillations when perfused over Fura-2-dextran injected rat hepatocytes. An antibody to IPG suppressed the inhibitory effect of insulin on the [Ca2+]i ... More
Practical aspects of measuring [Ca2+] with fluorescent indicators.
AuthorsKao JP
JournalMethods Cell Biol
PubMed ID8201975
Image analysis of calcium release dynamics.
AuthorsFreisinger CM, Houston DW, Slusarski DC,
JournalMethods Mol Biol
PubMed ID19099252
Many aspects of animal development are dependent on the dynamic release of calcium (Ca2+) ions. Although Ca2+ release within a cell is tightly controlled, how the release dynamics result in a specific biological output in embryonic development is less clear. The integration of pharmacological and molecular-genetic studies with in vivo ... More
Repetitive Ca2+ spikes in a unicellular green alga.
Cytosolic Ca2+ activity ([Ca2+]cy) and membrane potential were measured simultaneously in the unicellular green alga Eremosphaera viridis. Steady state [Ca2+]cy was about 160 nM. A 'light-off' stimulus induced a transient elevation of [Ca2+]cy ([Ca2+]cy spike) in parallel with a transient hyperpolarization of the plasma membrane. Caffeine and Sr2+, known to ... More
Monitoring presynaptic calcium dynamics in projection fibers by in vivo loading of a novel calcium indicator.
AuthorsKreitzer AC, Gee KR, Archer EA, Regehr WG
JournalNeuron
PubMed ID10939328
Fluorometric calcium measurements have revealed presynaptic residual calcium (Ca(res)) to be an important regulator of synaptic strength. However, in the mammalian brain, it has not been possible to monitor Ca(res) in fibers that project from one brain region to another. Here, we label neuronal projections by injecting dextran-conjugated calcium indicators ... More
The inositol trisphosphate receptor regulates a 50-second behavioral rhythm in C. elegans.
AuthorsDal Santo P, Logan MA, Chisholm AD, Jorgensen EM
JournalCell
PubMed ID10499793
The C. elegans defecation cycle is characterized by the contraction of three distinct sets of muscles every 50 s. Our data indicate that this cycle is regulated by periodic calcium release mediated by the inositol trisphosphate receptor (IP3 receptor). Mutations in the IP3 receptor slow down or eliminate the cycle, ... More
Calcium spiking in plant root hairs responding to Rhizobium nodulation signals.
AuthorsEhrhardt DW, Wais R, Long SR
JournalCell
PubMed ID8646776
SUMMARY: Rhizobium lipochitooligosaccharide signal molecules stimulate multiple responses in legume host plants, including changes in host gene expression, cell growth, and mitoses leading to root nodule development. The basis for signal transduction in the plant is not known. We examined cytoplasmic free calcium in host root hairs using calcium-sensitive reporter ... More
Mechanism of arachidonic acid-induced Ca2+ mobilization in liver nuclei.
AuthorsCatalán RE, Calcerrada MC, Miguel BG, Martínez AM
JournalJ Lipid Mediat Cell Signal
PubMed ID9524925
Arachidonic acid treatment in isolated liver nuclei resulted in a rapid and transient increase of Ca2+ concentration in the nucleoplasm which was monitored with the Ca(2+)-sensitive dye fura-2 dextran. This effect was associated with a decrease of Ca2+ concentration in the nuclear envelope as measured with fura-2 AM. Our results ... More
Biolistic delivery of Ca2+ dyes into plant and algal cells.
In eukaryotes, changes in cytosolic Ca2+ concentrations ([Ca2+]cyt) are associated with a number of environmental and developmental stimuli. However, measuring [Ca2+]cyt changes in single plant or algal cells is often problematic. Although a wide range of Ca2+-sensitive fluorescent dyes is available, they are often difficult to introduce into plant cells. ... More
Spatial organization of calcium dynamics in growth cones of sensory neurones.
AuthorsAmato A, Al-Mohanna FA, Bolsover S
JournalBrain Res Dev Brain Res
PubMed ID8861728
The concentration of calcium ions in the cytosol ([Ca2+]i) has a dominant influence on neuronal development. A [Ca2+]i rise can, depending on the amplitude and location, promote outgrowth or dramatically inhibit it. We have used the fluorescent calcium indicators Fura-2 and Fura-2 dextran to measure [Ca2+]i dynamics in sensory neurones ... More
Dishevelled activates Ca2+ flux, PKC, and CamKII in vertebrate embryos.
AuthorsSheldahl LC, Slusarski DC, Pandur P, Miller JR, Kühl M, Moon RT
JournalJ Cell Biol
PubMed ID12771126
Wnt ligands and Frizzled (Fz) receptors have been shown to activate multiple intracellular signaling pathways. Activation of the Wnt-beta-catenin pathway has been described in greatest detail, but it has been reported that Wnts and Fzs also activate vertebrate planar cell polarity (PCP) and Wnt-Ca2+ pathways. Although the intracellular protein Dishevelled ... More
Fast calcium signals in Drosophila motor neuron terminals.
AuthorsMacleod GT, Hegström-Wojtowicz M, Charlton MP, Atwood HL
JournalJ Neurophysiol
PubMed ID12424301
Drosophila is a powerful model for neuroscientists, but physiological techniques have not kept pace with advances in molecular genetics. We introduce a reliable assay for intracellular calcium dynamics in Drosophila larval motor neuron terminals, and a new physiological solution that improves the longevity of the larval preparation. By loading calcium ... More
Spectral characterization of the effect of viscosity on Fura-2 fluorescence: excitation wavelength optimization abolishes the viscosity artifact.
AuthorsBusa WB
JournalCell Calcium
PubMed ID1623501
A systematic study of the spectral characteristics of the viscosity artifact in Fura-2 based [Ca2+] measurements reveals that, by selecting excitation wavelengths approximately 10 nm longer than those routinely employed and modestly reducing excitation bandpasses, the magnitude of the artifact can be reduced to experimentally undetectable levels without greatly impairing ... More
Simultaneous blockade of intracellular calcium increases and of neuronal epileptiform depolarizations by verapamil.
AuthorsWiemann M, Jones D, Straub H, Altrup U, Speckmann EJ
JournalBrain Res
PubMed ID8896807
The specific L-type calcium channel blocker verapamil exerts an antiepileptic effect on neurons. This effect is assumed to depend on the blockade of transmembraneous calcium flux during epileptic discharges. In order to test this hypothesis, fura-dextran loaded snail neurons were rendered epileptic by pentylenetetrazole (40 mmol/l). The effect of verapamil ... More
ATP-dependent accumulation and inositol trisphosphate- or cyclic ADP-ribose-mediated release of Ca2+ from the nuclear envelope.
Uptake and release of Ca2+ from isolated liver nuclei were studied with fluorescent probes. We show with the help of digital imaging and confocal microscopy that the Ca(2+)-sensitive fluorescent probe Fura 2 is concentrated in or around the nuclear envelope and that the distribution of Fura 2 fluorescence is similar ... More
Membrane perforations inhibit lysosome fusion by altering pH and calcium in Listeria monocytogenes vacuoles.
AuthorsShaughnessy LM, Hoppe AD, Christensen KA, Swanson JA
JournalCell Microbiol
PubMed ID16611227
Listeria monocytogenes (Lm) evade microbicidal defences inside macrophages by secreting a pore-forming cytolysin listeriolysin O (LLO), which allows Lm to escape vacuoles. LLO also inhibits Lm vacuole fusion with lysosomes, which indicates LLO alters vacuole chemistry prior to release of Lm into cytoplasm. Using fluorescent probes to measure membrane permeability, ... More
Muscarinic signalling affects intracellular calcium concentration during the first cell cycle of sea urchin embryos.
The existence of a response to acetylcholine (ACh) and cholinomimetic drugs in sea urchin eggs and zygotes was investigated in two sea urchin species: Paracentrotus lividus and Lytechinus pictus. The calcium sensitive fluorescent probe, Fura-2 dextran, was employed to investigate the regulation of cytosolic free calcium concentration ([Ca(2+)](i)) by cholinomimetic ... More
Classes and mechanisms of calcium waves.
AuthorsJaffe LF
JournalCell Calcium
PubMed ID8131190
The best known calcium waves move at about 5-30 microns/s (at 20 degrees C) and will be called fast waves to distinguish them from slow (contractile) ones which move at 0.1-1 microns/s as well as electrically propagated, ultrafast ones. Fast waves move deep within cells and seem to underlie most ... More
Imaging calcium dynamics in the nervous system by means of ballistic delivery of indicators.
AuthorsKettunen P, Demas J, Lohmann C, Kasthuri N, Gong Y, Wong RO, Gan WB
JournalJ Neurosci Methods
PubMed ID12234633
The use of fluorescence-based calcium indicators has, over the years, unraveled important calcium-dependent mechanisms underlying neuronal function and development. However, difficulties associated with the loading of calcium indicators have limited their widespread use, particularly for the study of neuronal processing in the adult nervous system. Here, we show that in ... More
A transient rise in cytoplasmic free calcium is required to induce cytokinesis in zoosporangia of Phytophthora cinnamomi.
AuthorsJackson SL, Hardham AR
JournalEur J Cell Biol
PubMed ID8907619
We studied the role of cytoplasmic free Ca2+ concentration ([Ca2+]i) in cytokinesis of zoosporangia of the water mold Phytophthora cinnamomi. In these cells cytokinesis is separated from nuclear division and can be triggered at precisely determined times by cold shock. Changes in [Ca2+]i were monitored by ratiometric fluorescence imaging of ... More
Approaches to measuring calcium in zebrafish: focus on neuronal development.
AuthorsAshworth R
JournalCell Calcium
PubMed ID15003849
Calcium ions are known to act as important cellular signals during nervous system development. In vitro studies have provided significant information on the role of calcium signals during neuronal development; however, the function of this messenger in nervous system maturation in vivo remains to be established. The zebrafish has emerged ... More
Activation of a frizzled-2/beta-adrenergic receptor chimera promotes Wnt signaling and differentiation of mouse F9 teratocarcinoma cells via Galphao and Galphat.
AuthorsLiu X, Liu T, Slusarski DC, Yang-Snyder J, Malbon CC, Moon RT, Wang H
JournalProc Natl Acad Sci U S A
PubMed ID10588714
The frizzled gene family of putative Wnt receptors encodes proteins that have a seven-transmembrane-spanning motif characteristic of G protein-linked receptors, though no loss-of-function studies have demonstrated a requirement for G proteins for Frizzled signaling. We engineered a Frizzled-2 chimera responsive to beta-adrenergic agonist by using the ligand-binding domains of the ... More
Local perinuclear calcium signals associated with mitosis-entry in early sea urchin embryos.
AuthorsWilding M, Wright EM, Patel R, Ellis-Davies G, Whitaker M
JournalJ Cell Biol
PubMed ID8858173
Using calcium-sensitive dyes together with their dextran conjugates and confocal microscopy, we have looked for evidence of localized calcium signaling in the region of the nucleus before entry into mitosis, using the sea urchin egg first mitotic cell cycle as a model. Global calcium transients that appear to originate from ... More
Strontium-induced repetitive calcium spikes in a unicellular green alga
AuthorsBauer CS, Plieth C, Bethmann B, Popescu O, Hansen UP, Simonis W, Schonknecht G
JournalPlant Physiol
PubMed ID9625707
The divalent cation Sr2+ induced repetitive transient spikes of the cytosolic Ca2+ activity [Ca2+]cy and parallel repetitive transient hyperpolarizations of the plasma membrane in the unicellular green alga Eremosphaera viridis. [Ca2+]cy measurements, membrane potential measurements, and cation analysis of the cells were used to elucidate the mechanism of Sr2+-induced [Ca2+]cy ... More
Nuclear and cytosolic calcium changes in osteoclasts stimulated with ATP and integrin-binding peptide.
AuthorsParkinson N, Bolsover S, Mason W
JournalCell Calcium
PubMed ID9883275
Cytosolic calcium modulates the activity of osteoclasts, large multinucleate cells that resorb bone. Nuclear events, such as gene transcription, are also calcium-regulated in these cells, and fluorescence imaging has suggested that calcium signals produced by some stimuli are specifically targeted to, or amplified within, osteoclast nuclei. We used two alternative ... More
cAMP-induced changes in the cytosolic free Ca2+ concentration in Dictyostelium discoideum are light sensitive.
AuthorsSonnemann J, Knoll G, Schlatterer C
JournalCell Calcium
PubMed ID9232353
The cytosolic free calcium concentration ([Ca2+]i) of the social amoeba Dictyostelium discoideum was analyzed after challenge with the chemoattractant cAMP. [Ca2+]i was measured by digital imaging in single cells loaded with the Ca2+ indicator Fura-2-dextran. Global stimulation with low concentrations of cAMP (0.1-1 microM) led to a global transient [Ca2+]i ... 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
Spontaneous calcium oscillatory patterns in mammotropes display non-random dynamics.
AuthorsShorte SL, Faught WJ, Frawley LS
JournalCell Calcium
PubMed ID11020379
We previously showed that primary rat mammotropes exhibited four distinct patterns of 'spontaneous' free intracellular calcium ([Ca2+]i) oscillatory behavior: a quiescent state A and three oscillatory states B,C&D, which differed in frequency/amplitude characteristics. When [Ca2+]i was monitored in 10 min windows separated by several hours, these phenotypes were frequently found ... More
Spontaneous calcium oscillations control c-fos transcription via the serum response element in neuroendocrine cells.
AuthorsMaturana A, Van Haasteren G, Piuz I, Castelbou C, Demaurex N, Schlegel W
JournalJ Biol Chem
PubMed ID12121970
In excitable cells the localization of Ca2+ signals plays a central role in the cellular response, especially in the control of gene transcription. To study the effect of localized Ca2+ signals on the transcriptional activation of the c-fos oncogene, we stably expressed various c-fos beta-lactamase reporter constructs in pituitary AtT20 ... More
The NO pathway acts late during the fertilization response in sea urchin eggs.
AuthorsLeckie C, Empson R, Becchetti A, Thomas J, Galione A, Whitaker M
JournalJ Biol Chem
PubMed ID12540836
Both the inositol 1,4,5-trisphosphate (InsP(3)) and ryanodine receptor pathways contribute to the Ca(2+) transient at fertilization in sea urchin eggs. To date, the precise contribution of each pathway has been difficult to ascertain. Evidence has accumulated to suggest that the InsP(3) receptor pathway has a primary role in causing Ca(2+) ... More
Novel biochemical and functional insights into nuclear Ca(2+) transport through IP(3)Rs and RyRs in osteoblasts.
AuthorsAdebanjo OA, Biswas G, Moonga BS, Anandatheerthavarada HK, Sun L, Bevis PJ, Sodam BR, Lai FA, Avadhani NG, Zaidi M
JournalAm J Physiol Renal Physiol
PubMed ID10807590
We report the first biochemical and functional characterization of inositol trisphosphate receptors (IP(3)Rs) and ryanodine receptors (RyRs) in the nuclear membrane of bone-forming (MC3T3-E1) osteoblasts. Intact nuclei fluoresced intensely with anti-RyR (Ab(34)) and anti-IP(3)R (Ab(40)) antisera in a typically peripheral nuclear membrane pattern. Isolated nuclear membranes were next subjected to ... More
The role of X/Y linker region and N-terminal EF-hand domain in nuclear translocation and Ca2+ oscillation-inducing activities of phospholipase Czeta, a mammalian egg-activating factor.
AuthorsKuroda K, Ito M, Shikano T, Awaji T, Yoda A, Takeuchi H, Kinoshita K, Miyazaki S
JournalJ Biol Chem
PubMed ID16854985
Sperm-specific phospholipase C-zeta (PLCzeta) causes intracellular Ca(2+) oscillations and thereby egg activation and is accumulated into the formed pronucleus (PN) when expressed in mouse eggs by injection of cRNA encoding PLCzeta, which consists of four EF-hand domains (EF1-EF4) in the N terminus, X and Y catalytic domains, and C-terminal C2 ... More
The Cytosolic Ca2+ Concentration Gradient of Sinapis alba Root Hairs as Revealed by Ca2+-Selective Microelectrode Tests and Fura-Dextran Ratio Imaging.
AuthorsFelle HH, Hepler PK
JournalPlant Physiol
PubMed ID12223687
Using Ca2+-selective microelectrodes and fura 2-dextran ratio imaging, the cytosolic free [Ca2+] was measured in Sinapis alba root hair cells. Both methods yielded comparable results, i.e. values between 158 to 251 nM for the basal [Ca2+] of the cells and an elevated [Ca2+] of 446 to 707 nM in the ... More
Steady state relation between cytoplasmic free Ca2+ concentration and force in intact frog skeletal muscle fibers.
AuthorsKonishi M, Watanabe M
JournalJ Gen Physiol
PubMed ID9524135
The steady state relation between cytoplasmic Ca2+ concentration ([Ca2+]i) and force was studied in intact skeletal muscle fibers of frogs. Intact twitch fibers were injected with the dextran-conjugated Ca2+ indicator, fura dextran, and the fluorescence signals of fura dextran were converted to [Ca2+]i using calibration parameters previously estimated in permeabilized ... More
Resting cytoplasmic free Ca2+ concentration in frog skeletal muscle measured with fura-2 conjugated to high molecular weight dextran.
AuthorsKonishi M, Watanabe M
JournalJ Gen Physiol
PubMed ID8786353
Intact frog skeletal muscle fibers were injected with the Ca2+ indicator fura-2 conjugated to high molecular weight dextran (fura dextran, MW approximately 10,000; dissociation constant for Ca2+, 0.52 microM), and the fluorescence was measured from cytoplasm (17 degrees C). The fluorescence excitation spectrum of fura dextran measured in resting fibers ... More
Electrically induced calcium elevation, activation, and parthenogenetic development of bovine oocytes.
The influence of electrical stimulation on the level of intracellular Ca2+ in bovine oocytes, as well as activation and extent of parthenogenetic development, was investigated. Mature oocytes were electrically stimulated at 29 hr of maturation, and intracellular Ca2+ concentration was determined with the Ca2+ indicator fura-2 dextran (fura-2 D). The ... More
Electrophysiological effects of basolateral [Na+] in Necturus gallbladder epithelium.
AuthorsAltenberg GA, Stoddard JS, Reuss L
JournalJ Gen Physiol
PubMed ID1613485
In Necturus gallbladder epithelium, lowering serosal [Na+] ([Na+]s) reversibly hyperpolarized the basolateral cell membrane voltage (Vcs) and reduced the fractional resistance of the apical membrane (fRa). Previous results have suggested that there is no sizable basolateral Na+ conductance and that there are apical Ca(2+)-activated K+ channels. Here, we studied the ... More
Calcium imaging of rhythmic network activity in the developing spinal cord of the chick embryo.
AuthorsO'Donovan M, Ho S, Yee W
JournalJ Neurosci
PubMed ID7965041
Video-rate imaging of spinal neurons loaded with calcium-sensitive dyes was used to investigate the calcium dynamics and cellular organization of spontaneously active rhythm-generating networks in the spinal cord of E9-E12 chick embryos. Spinal neurons were loaded with bath-applied fura-2am. Motoneurons were also loaded by retrograde labeling with dextran-conjugated, calcium-sensitive dyes. ... More
Ca2+ release from intracellular stores induced by afferent stimulation of CA3 pyramidal neurons in hippocampal slices.
AuthorsMiller LD, Petrozzino JJ, Golarai G, Connor JA
JournalJ Neurophysiol
PubMed ID8836243
1. Ca2+ imaging and simultaneous intracellular recording were performed on CA3 pyramidal neurons in hippocampal slice cultures and standard acute slices. Both fura-2 and a dextran conjugate of fura-2 (MW = 10,000) were used in the Ca2+ measurements to control for compartmentalization artifacts. Experiments were performed under conditions giving minimal ... More
Fatty acids induce release of Ca2+ from acidosomal stores and activate capacitative Ca2+ entry in Dictyostelium discoideum.
AuthorsSchaloske R, Sonnemann J, Malchow D, Schlatterer C
JournalBiochem J
PubMed ID9601085
cAMP-induced Ca2+ fluxes in Dictyostelium discoideum largely depend on phospholipase A2 activity generating non-esterified fatty acids [Schaloske and Malchow (1997) Biochem. J. 327, 233-238]. In the present study the effect of fatty acids on Ca2+ homoeostasis in D. discoideum was investigated. Cytosolic free Ca2+ concentration ([Ca2+]i) was analysed by digital ... More
Lipoprotein(a) stimulates growth of human mesangial cells and induces activation of phospholipase C via pertussis toxin-sensitive G proteins.
AuthorsMondorf UF, Piiper A, Herrero M, Olbrich HG, Bender M, Gross W, Scheuermann E, Geiger H
JournalKidney Int
PubMed ID10201000
BACKGROUND: Renal disease is commonly associated with hyperlipidemia and correlates with glomerular accumulation of atherogenic lipoproteins, for example, lipoprotein(a) [Lp(a)], and mesangial hypercellularity. Specific binding of Lp(a) to mesangial cells and induction of c-myc and c-fos expression has been demonstrated. Therefore, in this study, we investigated a possible growth stimulatory ... More
Tip-localized calcium entry fluctuates during pollen tube growth.
AuthorsPierson ES, Miller DD, Callaham DA, van Aken J, Hackett G, Hepler PK
JournalDev Biol
PubMed ID8626016
Studies have been conducted on the dynamics of Ca2+ entry in pollen tubes using ratiometric ion imaging to measure the intracellular gradient and an ion selective vibrating electrode to detect the extracellular influx. A steep tip-focused gradient occurs in all species examined, including Lilium longiflorum, Nicotiana sylvestris, and Tradescantia virginiana. ... More
Injection of a porcine sperm factor triggers calcium oscillations in mouse oocytes and bovine eggs.
AuthorsWu H, He CL, Fissore RA
JournalMol Reprod Dev
PubMed ID9021749
Fertilization in mammals is associated with the generation of intracellular calcium ([Ca2+]i) oscillations. The site of, or mechanism(s) utilized by, the sperm to initiate and maintain these Ca2+ responses is not known. In this study, we tested the hypothesis that a factor from the sperm is capable, upon release into ... More
Human glucosamine-6-phosphate isomerase, a homologue of hamster oscillin, does not appear to be involved in Ca2+ release in mammalian oocytes.
AuthorsWolny YM, Fissore RA, Wu H, Reis MM, Colombero LT, Ergün B, Rosenwaks Z, Palermo GD
JournalMol Reprod Dev
PubMed ID10206659
Injections of cytosolic preparations from mammalian sperm into oocytes have been shown to trigger calcium [Ca2+]i oscillations and initiate activation of development. Recently, a protein isolated from hamster sperm has been suggested to be involved in the generation of these oscillations and it was named "oscillin." The human homologue of ... More
Mechanism of calcium oscillations in fertilized rabbit eggs.
AuthorsFissore RA, Robl JM
JournalDev Biol
PubMed ID7813782
Changes in intracellular calcium concentrations ([Ca2+]i) occur at regular intervals following fertilization in eggs of all mammalian species studied to date. To investigate the mechanisms of their generation, rabbit eggs were injected with the fluorescent Ca2+ indicator fura-2 dextran. [Ca2+]i oscillations were associated with fertilization (n = 10) and inositol ... More
Two components of transmitter release from the chick ciliary presynaptic terminal and their regulation by protein kinase C.
AuthorsYawo H
JournalJ Physiol
PubMed ID10087345
1. A study was made of the effects of phorbol ester (phorbol 12-myristate 13-acetate, PMA, 0.1 microM) on the two components of evoked transmitter release, namely the fast synchronous and the slow asynchronous components, from the giant presynaptic terminal of the chick ciliary ganglion. The excitatory postsynaptic currents (EPSCs) were ... More
On the roles of Ca2+ diffusion, Ca2+ buffers, and the endoplasmic reticulum in IP3-induced Ca2+ waves.
AuthorsJafri MS, Keizer J
JournalBiophys J
PubMed ID8580358
We have investigated the effects of Ca2+ diffusion, mobile and stationary Ca2+ buffers in the cytosol, and Ca2+ handling by the endoplasmic reticulum on inositol 1,4,5-trisphosphate-induced Ca2+ wave propagation. Rapid equilibration of free and bound Ca2+ is used to describe Ca2+ sequestration by buffers in both the cytosol and endoplasmic ... More
Dummies versus air puffs: efficient stimulus delivery for low-volatile odors.
Authors
JournalChem Senses
PubMed ID20212009
Representation of thermal information in the antennal lobe of leaf-cutting ants.
Authors
JournalFront Behav Neurosci
PubMed ID21120133
Organization of the olfactory pathway and odor processing in the antennal lobe of the ant Camponotus floridanus.
Authors
JournalJ Comp Neurol
PubMed ID18041786
Friends and foes from an ant brain's point of view--neuronal correlates of colony odors in a social insect.
Authors
JournalPLoS One
PubMed ID21731724
Distinct antennal lobe phenotypes in the leaf-cutting ant (Atta vollenweideri).
Authors
JournalJ Comp Neurol
PubMed ID19950119
Distributed representation of social odors indicates parallel processing in the antennal lobe of ants.
Authors
JournalJ Neurophysiol
PubMed ID21849606
[Mg2+]o/[Ca2+]o determines Ca2+ response at fertilization: tuning of adult phenotype?
Authors
JournalReproduction
PubMed ID28851827
Cytosolic calcium coordinates mitochondrial energy metabolism with presynaptic activity.