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Paeger A, Fillafer C, Schneider MF. Evidence for a transition in the cortical membranes of Paramecium. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184073. [PMID: 36243036 DOI: 10.1016/j.bbamem.2022.184073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 09/02/2022] [Accepted: 10/07/2022] [Indexed: 11/06/2022]
Abstract
Ever since the pioneering studies in the 1960s and 70s, the importance of order transitions for cell membrane functions has remained a matter of debate. Recently, it has been proposed that the nonlinear stimulus-response curve of excitable cells, which manifests in all-or-none pulses (action potentials (AP)), is due to a transition in the cell membrane. Indeed, evidence for transitions has accumulated in plant cells and neurons, but studies with other excitable cells are expedient in order to show if this finding is of a general nature. Herein, we investigated intact, motile specimens of the "swimming neuron" Paramecium. The cellular membranes were labelled with the solvatochromic fluorophores LAURDAN or Di-4-ANEPPDHQ. Subsequently, a cell was trapped in a microfluidic channel and investigated by fluorescence spectroscopy. The generalized polarization (GP) of the fluorescence emission from cell cortical membranes (probably plasma and alveolar membranes) was extracted by an edge-finding algorithm. The thermo-optical state diagram, i.e. the dependence of GP on temperature, exhibited clear indications for a reversible transition. This transition had a width of ~10-15 °C and a midpoint that was located ~4 °C below the growth temperature. The state diagrams with LAURDAN and Di-4-ANEPPDHQ had widely identical characteristics. These results suggested that the cortical membranes of Paramecium reside in an order transition regime under physiological growth conditions. Based on these findings, membrane potential fluctuations, spontaneous depolarizing spikes, and thermal excitation of Paramecium was interpreted.
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Affiliation(s)
- Anne Paeger
- Medical and Biological Physics, Department of Physics, Technical University Dortmund, Otto-Hahn-Str. 4, 44227 Dortmund, Germany.
| | - Christian Fillafer
- Medical and Biological Physics, Department of Physics, Technical University Dortmund, Otto-Hahn-Str. 4, 44227 Dortmund, Germany.
| | - Matthias F Schneider
- Medical and Biological Physics, Department of Physics, Technical University Dortmund, Otto-Hahn-Str. 4, 44227 Dortmund, Germany.
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Kunita I, Yamaguchi T, Tero A, Akiyama M, Kuroda S, Nakagaki T. A ciliate memorizes the geometry of a swimming arena. J R Soc Interface 2017; 13:rsif.2016.0155. [PMID: 27226383 DOI: 10.1098/rsif.2016.0155] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Accepted: 04/20/2016] [Indexed: 11/12/2022] Open
Abstract
Previous studies on adaptive behaviour in single-celled organisms have given hints to the origin of their memorizing capacity. Here we report evidence that a protozoan ciliate Tetrahymena has the capacity to learn the shape and size of its swimming space. Cells confined in a small water droplet for a short period were found to recapitulate circular swimming trajectories upon release. The diameter of the circular trajectories and their duration reflected the size of the droplet and the period of confinement. We suggest a possible mechanism for this adaptive behaviour based on a Ca(2+) channel. In our model, repeated collisions with the walls of a confining droplet result in a slow rise in intracellular calcium that leads to a long-term increase in the reversal frequency of the ciliary beat.
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Affiliation(s)
- Itsuki Kunita
- Research Institute for Electronic Science, Hokkaido University, N20W10, Kita-Ward Sapporo 001-0020, Japan
| | - Tatsuya Yamaguchi
- Graduate School of Mathematics, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Atsushi Tero
- Graduate School of Mathematics, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan Institute of Mathematics for Industry, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Masakazu Akiyama
- Research Institute for Electronic Science, Hokkaido University, N20W10, Kita-Ward Sapporo 001-0020, Japan
| | - Shigeru Kuroda
- Research Institute for Electronic Science, Hokkaido University, N20W10, Kita-Ward Sapporo 001-0020, Japan
| | - Toshiyuki Nakagaki
- Research Institute for Electronic Science, Hokkaido University, N20W10, Kita-Ward Sapporo 001-0020, Japan
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Jin K, Klima JC, Deane G, Dale Stokes M, Latz MI. Pharmacological investigation of the bioluminescence signaling pathway of the dinoflagellate Lingulodinium polyedrum: evidence for the role of stretch-activated ion channels. JOURNAL OF PHYCOLOGY 2013; 49:733-745. [PMID: 27007206 DOI: 10.1111/jpy.12084] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Accepted: 04/20/2013] [Indexed: 06/05/2023]
Abstract
Dinoflagellate bioluminescence serves as a whole-cell reporter of mechanical stress, which activates a signaling pathway that appears to involve the opening of voltage-sensitive ion channels and release of calcium from intracellular stores. However, little else is known about the initial signaling events that facilitate the transduction of mechanical stimuli. In the present study using the red tide dinoflagellate Lingulodinium polyedrum (Stein) Dodge, two forms of dinoflagellate bioluminescence, mechanically stimulated and spontaneous flashes, were used as reporter systems to pharmacological treatments that targeted various predicted signaling events at the plasma membrane level of the signaling pathway. Pretreatment with 200 μM Gadolinium III (Gd(3+) ), a nonspecific blocker of stretch-activated and some voltage-gated ion channels, resulted in strong inhibition of both forms of bioluminescence. Pretreatment with 50 μM nifedipine, an inhibitor of L-type voltage-gated Ca(2+) channels that inhibits mechanically stimulated bioluminescence, did not inhibit spontaneous bioluminescence. Treatment with 1 mM benzyl alcohol, a membrane fluidizer, was very effective in stimulating bioluminescence. Benzyl alcohol-stimulated bioluminescence was inhibited by Gd(3+) but not by nifedipine, suggesting that its role is through stretch activation via a change in plasma membrane fluidity. These results are consistent with the presence of stretch-activated and voltage-gated ion channels in the bioluminescence mechanotransduction signaling pathway, with spontaneous flashing associated with a stretch-activated component at the plasma membrane.
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Affiliation(s)
- Kelly Jin
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, 92093, USA
| | - Jason C Klima
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, 92093, USA
| | - Grant Deane
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, 92093, USA
| | - Malcolm Dale Stokes
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, 92093, USA
| | - Michael I Latz
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, 92093, USA
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Ooyama S, Shibata T. Hierarchical organization of noise generates spontaneous signal in Paramecium cell. J Theor Biol 2011; 283:1-9. [PMID: 21620864 DOI: 10.1016/j.jtbi.2011.05.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 05/09/2011] [Accepted: 05/11/2011] [Indexed: 11/19/2022]
Abstract
In many cellular processes, spontaneous activities are often the basis for their functioning. Paramecium cells change their swimming direction under a homogeneous environment, which is induced by a spontaneous signal generation in the membrane electric potential. For such a spontaneous activity, a theoretical model has been proposed by Oosawa (2007) [Biosystems 88, 191-201.], in which intracellular noise is hierarchically organized from thermal fluctuations to spike-like large fluctuations, which induces a signal to change spontaneously the swimming direction. Our analysis of the model shows that the system is a kind of excitable media, in which a spike is induced by a stochastic fluctuation. We show conditions of channels properties to have a spike train.
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Affiliation(s)
- Shunsuke Ooyama
- Department of Mathematical and Life Sciences, Hiroshima University, Higashi-Hiroshima, Hiroshima 739-8526, Japan
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Ramoino P, Milanese M, Candiani S, Diaspro A, Fato M, Usai C, Bonanno G. γ-Amino butyric acid (GABA) release in the ciliated protozoon Paramecium occurs by neuronal-like exocytosis. J Exp Biol 2010; 213:1251-8. [DOI: 10.1242/jeb.039594] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
SUMMARY
Paramecium primaurelia expresses a significant amount of γ-amino butyric acid (GABA). Paramecia possess both glutamate decarboxylase (GAD)-like and vesicular GABA transporter (vGAT)-like proteins, indicating the ability to synthesize GABA from glutamate and to transport GABA into vesicles. Using antibodies raised against mammalian GAD and vGAT, bands with an apparent molecular weight of about 67 kDa and 57 kDa were detected. The presence of these bands indicated a similarity between the proteins in Paramecium and in mammals. VAMP, syntaxin and SNAP, putative proteins of the release machinery that form the so-called SNARE complex, are present in Paramecium. Most VAMP, syntaxin and SNAP fluorescence is localized in spots that vary in size and density and are primarily distributed near the plasma membrane. Antibodies raised against mammal VAMP-3, sintaxin-1 or SNAP-25 revealed protein immunoblot bands having molecular weights consistent with those observed in mammals. Moreover, P. primaurelia spontaneously releases GABA into the environment, and this neurotransmitter release significantly increases after membrane depolarization. The depolarization-induced GABA release was strongly reduced not only in the absence of extracellular Ca2+ but also by pre-incubation with bafilomycin A1 or with botulinum toxin C1 serotype. It can be concluded that GABA occurs in Paramecium, where it is probably stored in vesicles capable of fusion with the cell membrane; accordingly, GABA can be released from Paramecium by stimulus-induced, neuronal-like exocytotic mechanisms.
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Affiliation(s)
- P. Ramoino
- Department for the Study of Territory and its Resources (DIP.TE.RIS.), University of Genoa, Corso Europa 26, 16132 Genova, Italy
| | - M. Milanese
- Department of Experimental Medicine, Section of Pharmacology and Toxicology, University of Genoa, Viale Cembrano 4, 16148 Genova, Italy
| | - S. Candiani
- Department of Biology, University of Genoa, Viale Benedetto XV, 16132 Genova, Italy
| | - A. Diaspro
- The Italian Institute of Technology (IIT), Nanophysics Unit, Via Morego 30, 16163 Genova, Italy
| | - M. Fato
- Department of Communication, Computer and System Sciences (DIST), University of Genoa, Viale Causa 13, 16145 Genova, Italy
| | - C. Usai
- Institute of Biophysics, CNR Genoa, Via De Marini 6, 16149 Genova, Italy
| | - G. Bonanno
- Department of Experimental Medicine, Section of Pharmacology and Toxicology, University of Genoa, Viale Cembrano 4, 16148 Genova, Italy
- Center of Excellence for Biomedical Research, University of Genoa, Viale Benedetto XV, 16132 Genova, Italy
- National Institute of Neuroscience, Corso Raffaello 30, 10125 Torino, Italy
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Nakaoka Y, Imaji T, Hara M, Hashimoto N. Spontaneous fluctuation of the resting membrane potential in Paramecium: amplification caused by intracellular Ca2+. ACTA ACUST UNITED AC 2009; 212:270-6. [PMID: 19112146 DOI: 10.1242/jeb.023283] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The ciliated protozoan Paramecium spontaneously changes its swimming direction in the absence of external stimuli. Such behavior is based on resting potential fluctuations, the amplitudes of which reach a few mV. When the resting potential fluctuation is positive and large, a spike-like depolarization is frequently elicited that reverses the beating of the cilia associated with directional changes during swimming. We aimed to study how the resting potential fluctuation is amplified. Simultaneous measurements of the resting potential and intracellular Ca(2+) ([Ca(2+)](i)) from a deciliated cell showed that positive potential fluctuations were frequently accompanied by a small increase in [Ca(2+)](i). This result suggests that Ca(2+) influx through the somatic membrane occurs during the resting state. The mean amplitude of the resting potential fluctuation was largely decreased by either an intracellular injection of a calcium chelater (BAPTA) or by an extracellular addition of Ba(2+). Hence, a small increase in [Ca(2+)](i) amplifies the resting potential fluctuation. Simulation analysis of the potential fluctuation was made by assuming that Ca(2+) and K(+) channels of surface membrane are fluctuating between open and closed states. The simulated fluctuation increased to exhibit almost the same amplitude as the measured fluctuation using the assumption that a small Ca(2+) influx activates Ca(2+) channels in a positive feedback manner.
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Affiliation(s)
- Yasuo Nakaoka
- Biophysical Dynamics Laboratories, Graduate School of Frontier Bioscience, Osaka University, Toyonaka, Osaka 560-8531, Japan.
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Abstract
The purpose of this article is to give a theoretical framework to describe the mechanism of internal signal generation and discuss the physiological significance of spontaneous activities of certain living cells [Oosawa, F., 2001. Spontaneous signal generation in living cells. Bull. Math. Biol. 63, 643].
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Affiliation(s)
- Fumio Oosawa
- Aichi Institute of Technology, 2-17-1 Haruoka, Nagoya 464-0848, Japan.
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Schultz JE, Schönborn C. Cyclic AMP formation in Tetrahymena pyriformis is controlled by a K(+)-conductance. FEBS Lett 1994; 356:322-6. [PMID: 7805864 DOI: 10.1016/0014-5793(94)01300-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Responses of the cAMP generating system of Tetrahymena to changes in the concentrations of external [K+] or [Ca2+] ions were examined. When Tetrahymena are equilibrated in high [K+] buffers, intracellular levels of cAMP decreased to 40% within 2 h. Hyperpolarization of the cells by dilution of external [K+] to one-eighth of its original concentration instantly stimulated intracellular cAMP formation. Manipulations of the K+ resting conductance of Tetrahymena by equilibration in buffers of different K+ content greatly affected the responsivity of the adenylyl cyclase. Hyperpolarization of the cell by addition of Ca2+ also resulted in a rapid generation of cAMP. Blockade of K+ conductances by the K+ channel blockers tetraethylammonium, quinine, and Cs+, dose-dependently inhibited hyperpolarization-stimulated cAMP formation. The data indicate that a hyperpolarization-activated K+ current is directly coupled to adenylyl cyclase regulation.
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Affiliation(s)
- J E Schultz
- Universität Tübingen, Fakultät für Chemie und Pharmazie, Germany
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Schultz JE, Klumpp S, Benz R, Schürhoff-Goeters WJ, Schmid A. Regulation of adenylyl cyclase from Paramecium by an intrinsic potassium conductance. Science 1992; 255:600-3. [PMID: 1371017 DOI: 10.1126/science.1371017] [Citation(s) in RCA: 132] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Hyperpolarization of the cell membrane of Paramecium stimulates adenosine 3',5'-monophosphate (cAMP) formation. Manipulations of the K+ resting conductance of the ciliate by adaptation in different buffers affected excitability of the cAMP generating system. Blockade of K+ channels inhibited hyperpolarization-stimulated cAMP formation. A mutant of Paramecium that is unable to control its K+ resting conductance had a defect in cAMP formation. Purified adenylyl cyclase, when incorporated into an artificial lipid bilayer membrane, revealed properties of a voltage-independent K+ channel. This indicates that the adenylyl cyclase of Paramecium has a secondary function as carrier of the K+ resting conductance. A hyperpolarization-activated K+ efflux appears to directly regulate adenylyl cyclase activity in vivo.
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Affiliation(s)
- J E Schultz
- Pharmazeutisches Institut, Universität Tübingen, Germany
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Connolly JG, Kerkut G. Ion regulation and membrane potential in tetrahymena and paramecium. ACTA ACUST UNITED AC 1983. [DOI: 10.1016/0300-9629(83)90285-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Oosawa F, Masai J. Asymmetry of fluctuation with respect to time reversal in steady states of biological systems. Biophys Chem 1982; 16:33-40. [PMID: 7139039 DOI: 10.1016/0301-4622(82)85005-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
The asymmetry of fluctuation with respect to time reversal which is expected in an energy-consuming steady state is discussed with special attention to biological systems. The necessary condition for asymmetry of fluctuation of an observed quantity is given. To show the usefulness of the experimental analysis of asymmetry of fluctuation, some calculations are carried out on two simple examples of three-state reactions. In one of them, the two-point time correlation function of the observed quantity has an oscillatory component, while in the other the function is nearly exponential, but in both cases, the fluctuation has a pronounced asymmetry. A method to estimate the degree of asymmetry of fluctuation is proposed, and the application of the present method to investigation of the molecular events in biological systems such as muscle is discussed.
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