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Rodgers MJ, Staves MP. Mechanosensing and anesthesia of single internodal cells of Chara. PLANT SIGNALING & BEHAVIOR 2024; 19:2339574. [PMID: 38601988 PMCID: PMC11017945 DOI: 10.1080/15592324.2024.2339574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Accepted: 03/29/2024] [Indexed: 04/12/2024]
Abstract
The giant (2-3 × 10-2 m long) internodal cells of the aquatic plant, Chara, exhibit a rapid (>100 × 10-6 m s-1) cyclic cytoplasmic streaming which stops in response to mechanical stimuli. Since the streaming - and the stopping of streaming upon stimulation - is easily visible with a stereomicroscope, these single cells are ideal tools to investigate mechanosensing in plant cells, as well as the potential for these cells to be anesthetized. We found that dropping a steel ball (0.88 × 10-3 kg, 6 × 10-3 m in diameter) through a 4.6 cm long tube (delivering ca. 4 × 10-4 J) reliably induced mechanically-stimulated cessation of cytoplasmic streaming. To determine whether mechanically-induced cessation of cytoplasmic streaming in Chara was sensitive to anesthesia, we treated Chara internodal cells to volatilized chloroform in a 9.8 × 10-3 m3 chamber for 2 minutes. We found that low doses (15,000-25,000 ppm) of chloroform did not always anesthetize cells, whereas large doses (46,000 and higher) proved lethal. However, 31,000 ppm chloroform completely, and reversibly, anesthetized these cells in that they did not stop cytoplasmic streaming upon mechanostimulation, but after 24 hours the cells recovered their sensitivity to mechanostimulation. We believe this single-cell model will prove useful for elucidating the still obscure mode of action of volatile anesthetics.
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Affiliation(s)
- Manya J. Rodgers
- Department of Cell and Molecular Biology, Grand Valley State University, Allendale, MI, USA
| | - Mark P. Staves
- Department of Cell and Molecular Biology, Grand Valley State University, Allendale, MI, USA
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Silic MR, Zhang G. Bioelectricity in Developmental Patterning and Size Control: Evidence and Genetically Encoded Tools in the Zebrafish Model. Cells 2023; 12:cells12081148. [PMID: 37190057 DOI: 10.3390/cells12081148] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2023] [Revised: 04/03/2023] [Accepted: 04/10/2023] [Indexed: 05/17/2023] Open
Abstract
Developmental patterning is essential for regulating cellular events such as axial patterning, segmentation, tissue formation, and organ size determination during embryogenesis. Understanding the patterning mechanisms remains a central challenge and fundamental interest in developmental biology. Ion-channel-regulated bioelectric signals have emerged as a player of the patterning mechanism, which may interact with morphogens. Evidence from multiple model organisms reveals the roles of bioelectricity in embryonic development, regeneration, and cancers. The Zebrafish model is the second most used vertebrate model, next to the mouse model. The zebrafish model has great potential for elucidating the functions of bioelectricity due to many advantages such as external development, transparent early embryogenesis, and tractable genetics. Here, we review genetic evidence from zebrafish mutants with fin-size and pigment changes related to ion channels and bioelectricity. In addition, we review the cell membrane voltage reporting and chemogenetic tools that have already been used or have great potential to be implemented in zebrafish models. Finally, new perspectives and opportunities for bioelectricity research with zebrafish are discussed.
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Affiliation(s)
- Martin R Silic
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA
| | - GuangJun Zhang
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA
- Center for Cancer Research, Purdue University, West Lafayette, IN 47907, USA
- Purdue Institute for Inflammation, Immunology and Infectious Diseases (PI4D), Purdue University, West Lafayette, IN 47907, USA
- Purdue Institute for Integrative Neuroscience, Purdue University, 625 Harrison Street, West Lafayette, IN 47907, USA
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3
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Fromm J, Lautner S. Electrical Signaling and Its Functions Under Conditions of Abiotic Stress: A Review of Methodological Approaches and Physiological Implications. Methods Mol Biol 2023; 2642:179-193. [PMID: 36944879 DOI: 10.1007/978-1-0716-3044-0_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/23/2023]
Abstract
In contrast to chemical messengers, electrical signals such as action potentials and variation potentials can transmit information much faster over long distances. Electrical signals can be triggered by various abiotic stress factors and are propagated via plasmodesmata over short distances and within the phloem over long distances. Thus, in addition to assimilate transport from sources to sinks, the phloem serves as a communication highway for various types of information. Key factors for systemic signaling in the phloem are peptides, RNAs, hormones, and electrical signals. In recent years, there has been increasing evidence that rapid communication by means of electrical signals is essential for various plant physiological processes. Thus, this chapter focuses on electrical signaling and various associated physiological effects, such as regulation of leaf movements, assimilate transport, photosynthesis, and gas exchange, as well as plant water status.
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Affiliation(s)
- Jörg Fromm
- Wood Biology, Institute for Wood Science, Universität Hamburg, Hamburg, Germany.
| | - Silke Lautner
- Applied Wood Biology, Eberswalde University for Sustainable Development, Eberswalde, Germany
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Kisnieriene V, Trębacz K, Pupkis V, Koselski M, Lapeikaite I. Evolution of long-distance signalling upon plant terrestrialization: comparison of action potentials in Characean algae and liverworts. ANNALS OF BOTANY 2022; 130:457-475. [PMID: 35913486 PMCID: PMC9510943 DOI: 10.1093/aob/mcac098] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 07/27/2022] [Indexed: 06/15/2023]
Abstract
BACKGROUND In this review, we summarize data concerning action potentials (APs) - long-distance electrical signals in Characean algae and liverworts. These lineages are key in understanding the mechanisms of plant terrestrialization. Liverworts are postulated to be pioneer land plants, whereas aquatic charophytes are considered the closest relatives to land plants. The drastic change of the habitat was coupled with the adaptation of signalling systems to the new environment. SCOPE APs fulfil the 'all-or-nothing' law, exhibit refractory periods and propagate with a uniform velocity. Their ion mechanism in the algae and liverworts consists of a Ca2+ influx (from external and internal stores) followed by/coincident with a Cl- efflux, which both evoke the membrane potential depolarization, and a K+ efflux leading to repolarization. The molecular identity of ion channels responsible for these fluxes remains unknown. Publication of the Chara braunii and Marchantia polymorpha genomes opened up new possibilities for studying the molecular basis of APs. Here we present the list of genes which can participate in AP electrogenesis. We also point out the differences between these plant species, e.g. the absence of Ca2+-permeable glutamate receptors (GLRs) and Cl--permeable SLAC1 channel homologues in the Chara genome. Both these channels play a vital role in long-distance signalling in liverworts and vascular plants. Among the common properties of APs in liverworts and higher plants is their duration (dozens of seconds) and the speed of propagation (mm s-1), which are much slower than in the algae (seconds, and dozens of mm s-1, respectively). CONCLUSIONS Future studies with combined application of electrophysiological and molecular techniques should unravel the ion channel proteins responsible for AP generation, their regulation and transduction of those signals to physiological responses. This should also help to understand the adaptation of the signalling systems to the land environment and further evolution of APs in vascular plants.
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Affiliation(s)
| | | | - Vilmantas Pupkis
- Department of Neurobiology and Biophysics, Institute of Biosciences, Life Sciences Center, Vilnius University, Saulėtekio Ave, Vilnius, Lithuania
| | - Mateusz Koselski
- Department of Plant Physiology and Biophysics, Institute of Biological Sciences, Faculty of Biology and Biotechnology, Maria Curie-Sklodowska University, Akademicka, Lublin, Poland
| | - Indre Lapeikaite
- Department of Neurobiology and Biophysics, Institute of Biosciences, Life Sciences Center, Vilnius University, Saulėtekio Ave, Vilnius, Lithuania
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5
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de Bakker JMT, Belterman CNW, Coronel R. Excitability and propagation of the electrical impulse in Venus flytrap; a comparative electrophysiological study of unipolar electrograms with myocardial tissue. Bioelectrochemistry 2021; 140:107810. [PMID: 33845442 DOI: 10.1016/j.bioelechem.2021.107810] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 03/25/2021] [Accepted: 03/28/2021] [Indexed: 11/25/2022]
Abstract
Mammalian heart cells and cells of leaves of Dionaea muscipula share the ability to generate propagated action potentials, because the excitable cells are electrically coupled. In the heart the propagated action potential causes synchronized contraction of the heart muscle after automatic generation of the impulse in the sinus node. In Dionaea propagation results in closure of the trap after activation of trigger hairs by an insect. The electrical activity can be recorded in the extracellular space as an extracellular electrogram, resulting from transmembrane currents. Although the underlying physiological mechanism that causes the electrogram is similar for heart and Dionaea cells, the contribution of the various ions to the transmembrane current is different. We recorded extracellular electrograms from Dionaea leaves and compared the recorded signals with those known from the heart. The morphology of the electrograms differed considerably. In comparison to activation in mammalian myocardium, electrograms of Dionaea are more temporally and spatially variable. Whereas electrograms in healthy myocardium recorded at some distance from the site of activation reveal a simple biphasic pattern, Dionaea activation showed positive, negative or biphasic deflections. Comparison of patch clamp data from plant cells and cardiomyocytes suggests a role of temperature and ion concentrations in extracellular space for the diversity of morphologies of the Dionaea electrograms.
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Affiliation(s)
- Jacques M T de Bakker
- Heart Center, Department of Experimental Cardiology, Academic Medical Center, Meibergdreef 9, 1105AZ Amsterdam, the Netherlands.
| | - Charly N W Belterman
- Heart Center, Department of Experimental Cardiology, Academic Medical Center, Meibergdreef 9, 1105AZ Amsterdam, the Netherlands
| | - Ruben Coronel
- Heart Center, Department of Experimental Cardiology, Academic Medical Center, Meibergdreef 9, 1105AZ Amsterdam, the Netherlands
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Fabiunke S, Fillafer C, Paeger A, Schneider MF. Optical studies of membrane state during action potential propagation. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 162:69-78. [DOI: 10.1016/j.pbiomolbio.2020.11.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Revised: 10/05/2020] [Accepted: 11/13/2020] [Indexed: 10/23/2022]
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Fillafer C, Paeger A, Schneider MF. The living state: How cellular excitability is controlled by the thermodynamic state of the membrane. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 162:57-68. [PMID: 33058943 DOI: 10.1016/j.pbiomolbio.2020.10.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 10/08/2020] [Accepted: 10/08/2020] [Indexed: 12/16/2022]
Abstract
The thermodynamic (TD) properties of biological membranes play a central role for living systems. It has been suggested, for instance, that nonlinear pulses such as action potentials (APs) can only exist if the membrane state is in vicinity of a TD transition. Herein, two membrane properties in living systems - excitability and velocity - are analyzed for a broad spectrum of conditions (temperature (T), 3D-pressure (p) and pH-dependence). Based on experimental data from Characean cells and a review of literature we predict parameter ranges in which a transition of the membrane is located (15-35°C below growth temperature; 1-3pH units below pH7; at ∼800atm) and propose the corresponding phase diagrams. The latter explain: (i) changes of AP velocity with T,p and pH.(ii) The existence and origin of two qualitatively different forms of loss of nonlinear excitability ("nerve block", anesthesia). (iii) The type and quantity of parameter changes that trigger APs. Finally, a quantitative comparison between the TD behavior of 2D-lipid model membranes with living systems is attempted. The typical shifts in transition temperature with pH and p of model membranes agree with values obtained from cell physiological measurements. Taken together, these results suggest that it is not specific molecules that control the excitability of living systems but rather the TD properties of the membrane interface. The approach as proposed herein can be extended to other quantities (membrane potential, calcium concentration, etc.) and makes falsifiable predictions, for example, that a transition exists within the specified parameter ranges in excitable cells.
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Affiliation(s)
- Christian Fillafer
- Medical and Biological Physics, Department of Physics, Technical University Dortmund, Otto-Hahn-Str. 4, 44227, Dortmund, Germany.
| | - Anne Paeger
- 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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Mussel M, Schneider MF. Sound pulses in lipid membranes and their potential function in biology. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2020; 162:101-110. [DOI: 10.1016/j.pbiomolbio.2020.08.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 06/03/2020] [Accepted: 08/03/2020] [Indexed: 12/29/2022]
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9
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Zhang X, Chen L, Lim KH, Gonuguntla S, Lim KW, Pranantyo D, Yong WP, Yam WJT, Low Z, Teo WJ, Nien HP, Loh QW, Soh S. The Pathway to Intelligence: Using Stimuli-Responsive Materials as Building Blocks for Constructing Smart and Functional Systems. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2019; 31:e1804540. [PMID: 30624820 DOI: 10.1002/adma.201804540] [Citation(s) in RCA: 100] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 10/09/2018] [Indexed: 05/22/2023]
Abstract
Systems that are intelligent have the ability to sense their surroundings, analyze, and respond accordingly. In nature, many biological systems are considered intelligent (e.g., humans, animals, and cells). For man-made systems, artificial intelligence is achieved by massively sophisticated electronic machines (e.g., computers and robots operated by advanced algorithms). On the other hand, freestanding materials (i.e., not tethered to a power supply) are usually passive and static. Hence, herein, the question is asked: can materials be fabricated so that they are intelligent? One promising approach is to use stimuli-responsive materials; these "smart" materials use the energy supplied by a stimulus available from the surrounding for performing a corresponding action. After decades of research, many interesting stimuli-responsive materials that can sense and perform smart functions have been developed. Classes of functions discussed include practical functions (e.g., targeting and motion), regulatory functions (e.g., self-regulation and amplification), and analytical processing functions (e.g., memory and computing). The pathway toward creating truly intelligent materials can involve incorporating a combination of these different types of functions into a single integrated system by using stimuli-responsive materials as the basic building blocks.
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Affiliation(s)
- Xuan Zhang
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore
| | - Linfeng Chen
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore
| | - Kang Hui Lim
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore
| | - Spandhana Gonuguntla
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore
| | - Kang Wen Lim
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore
| | - Dicky Pranantyo
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore
| | - Wai Pong Yong
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore
| | - Wei Jian Tyler Yam
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore
| | - Zhida Low
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore
| | - Wee Joon Teo
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore
| | - Hao Ping Nien
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore
| | - Qiao Wen Loh
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore
| | - Siowling Soh
- Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, Singapore, 117585, Singapore
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Fillafer C, Mussel M, Muchowski J, Schneider MF. Cell Surface Deformation during an Action Potential. Biophys J 2019; 114:410-418. [PMID: 29401438 DOI: 10.1016/j.bpj.2017.11.3776] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Revised: 10/24/2017] [Accepted: 11/27/2017] [Indexed: 11/29/2022] Open
Abstract
The excitation of many cells and tissues is associated with cell mechanical changes. The evidence presented herein corroborates that single cells deform during an action potential. It is demonstrated that excitation of plant cells (Chara braunii internodes) is accompanied by out-of-plane displacements of the cell surface in the micrometer range (∼1-10 μm). The onset of cellular deformation coincides with the depolarization phase of the action potential. The mechanical pulse: 1) propagates with the same velocity as the electrical pulse (within experimental accuracy, ∼10 mm s-1), 2) is reversible, 3) in most cases is of biphasic nature (109 out of 152 experiments), and 4) is presumably independent of actin-myosin-motility. The existence of transient mechanical changes in the cell cortex is confirmed by micropipette aspiration experiments. A theoretical analysis demonstrates that this observation can be explained by a reversible change in the mechanical properties of the cell surface (transmembrane pressure, surface tension, and bending rigidity). Taken together, these findings contribute to the ongoing debate about the physical nature of cellular excitability.
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Affiliation(s)
- Christian Fillafer
- Department of Physics, Technical University of Dortmund, Dortmund, Germany
| | - Matan Mussel
- Department of Physics, Technical University of Dortmund, Dortmund, Germany; Department of Physics, University of Augsburg, Augsburg, Germany
| | - Julia Muchowski
- Department of Physics, Technical University of Dortmund, Dortmund, Germany
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Baluška F, Reber A. Sentience and Consciousness in Single Cells: How the First Minds Emerged in Unicellular Species. Bioessays 2019; 41:e1800229. [PMID: 30714631 DOI: 10.1002/bies.201800229] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 12/06/2018] [Indexed: 12/13/2022]
Abstract
A reductionistic, bottom-up, cellular-based concept of the origins of sentience and consciousness has been put forward. Because all life is based on cells, any evolutionary theory of the emergence of sentience and consciousness must be grounded in mechanisms that take place in prokaryotes, the simplest unicellular species. It has been posited that subjective awareness is a fundamental property of cellular life. It emerges as an inherent feature of, and contemporaneously with, the very first life-forms. All other varieties of mentation are the result of evolutionary mechanisms based on this singular event. Therefore, all forms of sentience and consciousness evolve from this original instantiation in prokaryotes. It has also been identified that three cellular structures and mechanisms that likely play critical roles here are excitable membranes, oscillating cytoskeletal polymers, and structurally flexible proteins. Finally, basic biophysical principles are proposed to guide those processes that underly the emergence of supracellular sentience from cellular sentience in multicellular organisms.
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Affiliation(s)
- František Baluška
- Institute of Cellular and Molecular Botany, University of Bonn, 53115 Bonn, Germany
| | - Arthur Reber
- Department of Psychology, University of British Columbia, Vancouver, Canada
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12
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Tamagawa H. Mathematical expression of membrane potential based on Ling's adsorption theory is approximately the same as the Goldman-Hodgkin-Katz equation. J Biol Phys 2018; 45:13-30. [PMID: 30392060 DOI: 10.1007/s10867-018-9512-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 09/10/2018] [Indexed: 10/27/2022] Open
Abstract
The Goldman-Hodgkin-Katz equation (GHK equation), one of the most successful achievements of membrane theory in electrophysiology, can precisely predict the membrane potential. Its conceptual foundation lies in the idea that the transmembrane ion transport across the plasma membrane is responsible for the membrane potential generation. However, the potential virtually equivalent to the membrane potential is generated even across the impermeable membrane. In this work, I discus the membrane potential generation mechanism and find that the potential formula based on the long-dismissed Ling's adsorption theory, which attributes the membrane potential generation to the mobile ion adsorption rather than the transmembrane ion transport, is the same as the GHK equation. Based on this finding, I derive a conclusion that the membrane potential is generated by the ion adsorption against the existing electrophysiological concept.
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Affiliation(s)
- Hirohisa Tamagawa
- Department of Mechanical Engineering, Faculty of Engineering, Gifu University, 1-1 Yanagido, Gifu, Gifu, 501-1193, Japan.
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13
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Vallverdú J, Castro O, Mayne R, Talanov M, Levin M, Baluška F, Gunji Y, Dussutour A, Zenil H, Adamatzky A. Slime mould: The fundamental mechanisms of biological cognition. Biosystems 2018; 165:57-70. [DOI: 10.1016/j.biosystems.2017.12.011] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 12/18/2017] [Accepted: 12/20/2017] [Indexed: 01/27/2023]
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Mussel M, Fillafer C, Ben-Porath G, Schneider MF. Surface deformation during an action potential in pearled cells. Phys Rev E 2018; 96:052406. [PMID: 29347751 DOI: 10.1103/physreve.96.052406] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Indexed: 01/03/2023]
Abstract
Electric pulses in biological cells (action potentials) have been reported to be accompanied by a propagating cell-surface deformation with a nanoscale amplitude. Typically, this cell surface is covered by external layers of polymer material (extracellular matrix, cell wall material, etc.). It was recently demonstrated in excitable plant cells (Chara braunii) that the rigid external layer (cell wall) hinders the underlying deformation. When the cell membrane was separated from the cell wall by osmosis, a mechanical deformation, in the micrometer range, was observed upon excitation of the cell. The underlying mechanism of this mechanical pulse has, to date, remained elusive. Herein we report that Chara cells can undergo a pearling instability, and when the pearled fragments were excited even larger and more regular cell shape changes were observed (∼10-100μm in amplitude). These transient cellular deformations were captured by a curvature model that is based on three parameters: surface tension, bending rigidity, and pressure difference across the surface. In this paper these parameters are extracted by curve-fitting to the experimental cellular shapes at rest and during excitation. This is a necessary step to identify the mechanical parameters that change during an action potential.
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Affiliation(s)
- Matan Mussel
- Department of Physics, Technical University of Dortmund, 44227 Dortmund, Germany.,Department of Physics, University of Augsburg, 86159 Augsburg, Germany
| | - Christian Fillafer
- Department of Physics, Technical University of Dortmund, 44227 Dortmund, Germany
| | - Gal Ben-Porath
- Center for Mathematical Philosophy, Ludwig Maximilian University, 80539 Munich, Germany
| | - Matthias F Schneider
- Department of Physics, Technical University of Dortmund, 44227 Dortmund, Germany
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15
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Baluška F, Yokawa K, Mancuso S, Baverstock K. Understanding of anesthesia - Why consciousness is essential for life and not based on genes. Commun Integr Biol 2016; 9:e1238118. [PMID: 28042377 PMCID: PMC5193047 DOI: 10.1080/19420889.2016.1238118] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2015] [Revised: 08/05/2016] [Accepted: 09/14/2016] [Indexed: 01/14/2023] Open
Abstract
Anesthesia and consciousness represent 2 mysteries not only for biology but also for physics and philosophy. Although anesthesia was introduced to medicine more than 160 y ago, our understanding of how it works still remains a mystery. The most prevalent view is that the human brain and its neurons are necessary to impose the effects of anesthetics. However, the fact is that all life can be anesthesized. Numerous theories have been generated trying to explain the major impact of anesthetics on our human-specific consciousness; switching it off so rapidly, but no single theory resolves this enduring mystery. The speed of anesthetic actions precludes any direct involvement of genes. Lipid bilayers, cellular membranes, and critical proteins emerge as the most probable primary targets of anesthetics. Recent findings suggest, rather surprisingly, that physical forces underlie both the anesthetic actions on living organisms as well as on consciousness in general.
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Affiliation(s)
| | - Ken Yokawa
- IZMB, University of Bonn, Kirschalle, Bonn, Germany
| | - Stefano Mancuso
- Department of Plant, Soil and Environmental Science & LINV, University of Florence, Sesto Fiorentino, Italy
| | - Keith Baverstock
- Department of Environmental Science, University of Eastern Finland, Kuopio, Finland
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16
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Abstract
The central nervous system (CNS) underlies memory, perception, decision-making, and behavior in numerous organisms. However, neural networks have no monopoly on the signaling functions that implement these remarkable algorithms. It is often forgotten that neurons optimized cellular signaling modes that existed long before the CNS appeared during evolution, and were used by somatic cellular networks to orchestrate physiology, embryonic development, and behavior. Many of the key dynamics that enable information processing can, in fact, be implemented by different biological hardware. This is widely exploited by organisms throughout the tree of life. Here, we review data on memory, learning, and other aspects of cognition in a range of models, including single celled organisms, plants, and tissues in animal bodies. We discuss current knowledge of the molecular mechanisms at work in these systems, and suggest several hypotheses for future investigation. The study of cognitive processes implemented in aneural contexts is a fascinating, highly interdisciplinary topic that has many implications for evolution, cell biology, regenerative medicine, computer science, and synthetic bioengineering.
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Affiliation(s)
- František Baluška
- Department of Plant Cell Biology, IZMB, University of Bonn Bonn, Germany
| | - Michael Levin
- Biology Department, Tufts Center for Regenerative and Developmental Biology, Tufts University Medford, MA, USA
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17
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Hedrich R, Salvador-Recatalà V, Dreyer I. Electrical Wiring and Long-Distance Plant Communication. TRENDS IN PLANT SCIENCE 2016; 21:376-387. [PMID: 26880317 DOI: 10.1016/j.tplants.2016.01.016] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Revised: 01/06/2016] [Accepted: 01/18/2016] [Indexed: 05/18/2023]
Abstract
Electrical signalling over long distances is an efficient way of achieving cell-to-cell communication in living organisms. In plants, the phloem can be considered as a 'green cable' that allows the transmission of action potentials (APs) induced by stimuli such as wounding and cold. Measuring phloem potential changes and separating them from secondary responses of surrounding tissues can be achieved using living aphids as bioelectrodes. Two glutamate receptor-like genes (GLR3.3 and 3.6) were identified as being involved in the propagation of electrical activity from the damaged to undamaged leaves. However, phloem APs are initiated and propagated independently of these glutamate receptors. Here, we propose new screening approaches to obtain further information on the components required for electrical signalling in phloem cables.
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Affiliation(s)
- Rainer Hedrich
- Institute for Molecular Plant Physiology and Biophysics, University of Würzburg, Julius-von-Sachs-Platz 2, 97082 Würzburg, Germany.
| | - Vicenta Salvador-Recatalà
- Institute for Molecular Plant Physiology and Biophysics, University of Würzburg, Julius-von-Sachs-Platz 2, 97082 Würzburg, Germany
| | - Ingo Dreyer
- Centro de Bioinformática y Simulación Molecular (CBSM), Universidad de Talca, 2 Norte 685, Talca, Chile.
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Evolution of rapid nerve conduction. Brain Res 2016; 1641:11-33. [PMID: 26879248 DOI: 10.1016/j.brainres.2016.02.015] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 02/04/2016] [Accepted: 02/05/2016] [Indexed: 01/29/2023]
Abstract
Rapid conduction of nerve impulses is a priority for organisms needing to react quickly to events in their environment. While myelin may be viewed as the crowning innovation bringing about rapid conduction, the evolution of rapid communication mechanisms, including those refined and enhanced in the evolution of myelin, has much deeper roots. In this review, a sequence is traced starting with diffusional communication, followed by transport-facilitated communication, the rise of electrical signaling modalities, the invention of voltage-gated channels and "all-or-none" impulses, the emergence of elongate nerve axons specialized for communication and their fine-tuning to enhance impulse conduction speeds. Finally within the evolution of myelin itself, several innovations have arisen and have been interactively refined for speed enhancement, including the addition and sealing of layers, their limitation by space availability, and the optimization of key parameters: channel density, lengths of exposed nodes and lengths of internodes. We finish by suggesting several design principles that appear to govern the evolution of rapid conduction. This article is part of a Special Issue entitled SI: Myelin Evolution.
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Hamilton ES, Schlegel AM, Haswell ES. United in diversity: mechanosensitive ion channels in plants. ANNUAL REVIEW OF PLANT BIOLOGY 2014; 66:113-37. [PMID: 25494462 PMCID: PMC4470482 DOI: 10.1146/annurev-arplant-043014-114700] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Mechanosensitive (MS) ion channels are a common mechanism for perceiving and responding to mechanical force. This class of mechanoreceptors is capable of transducing membrane tension directly into ion flux. In plant systems, MS ion channels have been proposed to play a wide array of roles, from the perception of touch and gravity to the osmotic homeostasis of intracellular organelles. Three families of plant MS ion channels have been identified: the MscS-like (MSL), Mid1-complementing activity (MCA), and two-pore potassium (TPK) families. Channels from these families vary widely in structure and function, localize to multiple cellular compartments, and conduct chloride, calcium, and/or potassium ions. However, they are still likely to represent only a fraction of the MS ion channel diversity in plant systems.
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Affiliation(s)
- Eric S. Hamilton
- Department of Biology, Washington University in Saint Louis, Saint Louis, Missouri 63130
| | - Angela M. Schlegel
- Department of Biology, Washington University in Saint Louis, Saint Louis, Missouri 63130
| | - Elizabeth S. Haswell
- Department of Biology, Washington University in Saint Louis, Saint Louis, Missouri 63130
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20
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Giménez C, Climent E, Aznar E, Martínez-Máñez R, Sancenón F, Marcos MD, Amorós P, Rurack K. Towards chemical communication between gated nanoparticles. Angew Chem Int Ed Engl 2014; 53:12629-33. [PMID: 25196078 DOI: 10.1002/anie.201405580] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Indexed: 02/03/2023]
Abstract
The design of comparatively simple and modularly configurable artificial systems able to communicate through the exchange of chemical messengers is, to the best of our knowledge, an unexplored field. As a proof-of-concept, we present here a family of nanoparticles that have been designed to communicate with one another in a hierarchical manner. The concept involves the use of capped mesoporous silica supports in which the messenger delivered by a first type of gated nanoparticle is used to open a second type of nanoparticle, which delivers another messenger that opens a third group of gated nanoobjects. We believe that the conceptual idea that nanodevices can be designed to communicate with one another may result in novel applications and will boost further advances towards cooperative systems with complex behavior as a result of the communication between simple abiotic individual components.
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Affiliation(s)
- Cristina Giménez
- Centro de Reconocimiento Molecular y Tecnológico (IDM), Unidad Mixta Universidad Politécnica de Valencia-Universidad de Valencia (Spain) http://idm.webs.upv.es/; Departamento de Química, Universidad Politécnica de Valencia, Camino de Vera s/n, 46022 Valencia (Spain); CIBER de Bioingeniería, Biomateriales y Nanomedicina
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21
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Giménez C, Climent E, Aznar E, Martínez-Máñez R, Sancenón F, Marcos MD, Amorós P, Rurack K. Über den chemischen Informationsaustausch zwischen gesteuerten Nanopartikeln. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201405580] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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22
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van Bel AJE, Furch ACU, Will T, Buxa SV, Musetti R, Hafke JB. Spread the news: systemic dissemination and local impact of Ca²⁺ signals along the phloem pathway. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:1761-87. [PMID: 24482370 DOI: 10.1093/jxb/ert425] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
We explored the idea of whether electropotential waves (EPWs) primarily act as vehicles for systemic spread of Ca(2+) signals. EPW-associated Ca(2+) influx may trigger generation and amplification of countless long-distance signals along the phloem pathway given the fact that gating of Ca(2+)-permeable channels is a universal response to biotic and abiotic challenges. Despite fundamental differences, both action and variation potentials are associated with a sudden Ca(2+) influx. Both EPWs probably disperse in the lateral direction, which could be of essential functional significance. A vast set of Ca(2+)-permeable channels, some of which have been localized, is required for Ca(2+)-modulated events in sieve elements. There, Ca(2+)-permeable channels are clustered and create so-called Ca(2+) hotspots, which play a pivotal role in sieve element occlusion. Occlusion mechanisms play a central part in the interaction between plants and phytopathogens (e.g. aphids or phytoplasmas) and in transient re-organization of the vascular symplasm. It is argued that Ca(2+)-triggered systemic signalling occurs in partly overlapping waves. The forefront of EPWs may be accompanied by a burst of free Ca(2+) ions and Ca(2+)-binding proteins in the sieve tube sap, with a far-reaching impact on target cells. Lateral dispersion of EPWs may induce diverse Ca(2+) influx and handling patterns (Ca(2+) signatures) in various cell types lining the sieve tubes. As a result, a variety of cascades may trigger the fabrication of signals such as phytohormones, proteins, or RNA species released into the sap stream after product-related lag times. Moreover, transient reorganization of the vascular symplasm could modify cascades in disjunct vascular cells.
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Affiliation(s)
- Aart J E van Bel
- Institute of General Botany, Justus-Liebig University, Senckenbergstrasse 17, D-35390 Giessen, Germany
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Herde O, Peña-Cortés H, Willmitzer L, Fisahn J. Time-Resolved Analysis of Signals Involved in Systemic Induction of Pin2 Gene Expression. ACTA ACUST UNITED AC 2014. [DOI: 10.1111/j.1438-8677.1998.tb00723.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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25
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Zhu GL. A New Turgor/Membrane Potential Probe Simultaneously Measures Turgor and Electrical Membrane Potential. ACTA ACUST UNITED AC 2014. [DOI: 10.1111/j.1438-8677.1996.tb00869.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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26
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Foissner I, Wasteneys GO. Characean internodal cells as a model system for the study of cell organization. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2014; 311:307-64. [PMID: 24952921 DOI: 10.1016/b978-0-12-800179-0.00006-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Giant internodal cells of characean green algae have been widely used for studying cellular physiology. This review emphasizes their significance for understanding cytoarchitecture and cytoplasmic reorganization. The cytoarchitecture of internodal cells undergoes pronounced, cytoskeleton-dependent changes during development and in response to environmental cues. Under bright light, internodes develop alternating bands of acid and alkaline pH at their surface that correlate with the differential size and abundance of cortical organelles and, in the genus Chara, with the size and distribution of convoluted plasma membrane domains known as charasomes. Wounding induces responses ranging from chloroplast detachment to deposition of wound walls. These properties and the possibility for mechanical manipulation make the internodal cell ideal for exploring plasma membrane domains, organelle interactions, vesicle trafficking, and local cell wall deposition. The significance of this model system will further increase with the application of molecular biological methods in combination with metabolomics and proteomics.
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Affiliation(s)
- Ilse Foissner
- Division of Plant Physiology, Department of Cell Biology, University of Salzburg, Salzburg, Austria.
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Monshausen GB, Haswell ES. A force of nature: molecular mechanisms of mechanoperception in plants. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:4663-80. [PMID: 23913953 PMCID: PMC3817949 DOI: 10.1093/jxb/ert204] [Citation(s) in RCA: 138] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The ability to sense and respond to a wide variety of mechanical stimuli-gravity, touch, osmotic pressure, or the resistance of the cell wall-is a critical feature of every plant cell, whether or not it is specialized for mechanotransduction. Mechanoperceptive events are an essential part of plant life, required for normal growth and development at the cell, tissue, and whole-plant level and for the proper response to an array of biotic and abiotic stresses. One current challenge for plant mechanobiologists is to link these physiological responses to specific mechanoreceptors and signal transduction pathways. Here, we describe recent progress in the identification and characterization of two classes of putative mechanoreceptors, ion channels and receptor-like kinases. We also discuss how the secondary messenger Ca(2+) operates at the centre of many of these mechanical signal transduction pathways.
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Affiliation(s)
| | - Elizabeth S. Haswell
- Department of Biology, Washington University in St Louis, St Louis, MO 63130, USA
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28
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Wilson ME, Maksaev G, Haswell ES. MscS-like mechanosensitive channels in plants and microbes. Biochemistry 2013; 52:5708-22. [PMID: 23947546 DOI: 10.1021/bi400804z] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The challenge of osmotic stress is something all living organisms must face as a result of environmental dynamics. Over the past three decades, innovative research and cooperation across disciplines have irrefutably established that cells utilize mechanically gated ion channels to release osmolytes and prevent cell lysis during hypoosmotic stress. Early electrophysiological analysis of the inner membrane of Escherichia coli identified the presence of three distinct mechanosensitive activities. The subsequent discoveries of the genes responsible for two of these activities, the mechanosensitive channels of large (MscL) and small (MscS) conductance, led to the identification of two diverse families of mechanosensitive channels. The latter of these two families, the MscS family, consists of members from bacteria, archaea, fungi, and plants. Genetic and electrophysiological analysis of these family members has provided insight into how organisms use mechanosensitive channels for osmotic regulation in response to changing environmental and developmental circumstances. Furthermore, determining the crystal structure of E. coli MscS and several homologues in several conformational states has contributed to our understanding of the gating mechanisms of these channels. Here we summarize our current knowledge of MscS homologues from all three domains of life and address their structure, proposed physiological functions, electrophysiological behaviors, and topological diversity.
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Affiliation(s)
- Margaret E Wilson
- Department of Biology, Washington University in St. Louis, Missouri 63130, United States
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29
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Marder M. Plant intelligence and attention. PLANT SIGNALING & BEHAVIOR 2013; 8:e23902. [PMID: 23425923 PMCID: PMC3906434 DOI: 10.4161/psb.23902] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 02/06/2013] [Indexed: 05/19/2023]
Abstract
This article applies the phenomenological model of attention to plant monitoring of environmental stimuli and signal perception. Three complementary definitions of attention as selectivity, modulation and perdurance are explained with reference to plant signaling and behaviors, including foraging, ramet placement and abiotic stress communication. Elements of animal and human attentive attitudes are compared with plant attention at the levels of cognitive focus, context and margin. It is argued that the concept of attention holds the potential of becoming a cornerstone of plant intelligence studies.
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Affiliation(s)
- Michael Marder
- Department of Philosophy; The University of the Basque Country; UPV-EHU; Ikerbasque: Basque Foundation for Science; Vitoria-Gasteiz, Basque Country
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30
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Calcium as a Trigger and Regulator of Systemic Alarms and Signals along the Phloem Pathway. LONG-DISTANCE SYSTEMIC SIGNALING AND COMMUNICATION IN PLANTS 2013. [DOI: 10.1007/978-3-642-36470-9_18] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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31
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Marder M. Plant intentionality and the phenomenological framework of plant intelligence. PLANT SIGNALING & BEHAVIOR 2012; 7:1365-72. [PMID: 22951403 PMCID: PMC3548850 DOI: 10.4161/psb.21954] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
This article aims to bridge phenomenology and the study of plant intelligence with the view to enriching both disciplines. Besides considering the world from the perspective of sessile organisms, it would be necessary, in keeping with the phenomenological framework, to rethink (1) the meaning of being-sessile and being-in-a-place; (2) the concepts of sentience and attention; (3) how aboveground and underground environments appear to plants; (4) the significance of modular development for our understanding of intelligence; and (5) the concept of communication within and between plants and plant tissues. What emerges from these discussions is the image of a mind embodied in plant life.
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Affiliation(s)
- Michael Marder
- IKERBASQUE, Basque Foundation for Science & Department of Philosophy, The University of the Basque Country, Vitoria-Gasteiz, Basque Country.
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32
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Thorhaug A, Berlyn G. A tribute to Lawrence Rogers Blinks (1900-1989): light and algae. PHOTOSYNTHESIS RESEARCH 2009; 100:129-141. [PMID: 19533413 DOI: 10.1007/s11120-009-9435-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2009] [Accepted: 05/05/2009] [Indexed: 05/27/2023]
Abstract
We honor Lawrence Rogers Blinks (1900-1989) in this tribute. We introduce his scientific life that started at the Harvard University, and ended at the Hopkins Marine Station of Stanford University. We discuss his pioneering contributions in the areas of ion transport in membranes and of photosynthesis, particularly of the phenomenon that became known as the Blinks Effect, later linked to the two-light and two-pigment system scheme of photosynthesis. We have drawn information from the 2006 symposium held in his honor in California, and from the extensive 2006 and 2008 recollections of Francis Haxo, one of the major coworkers of Blinks.
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Affiliation(s)
- Anitra Thorhaug
- School of Forestry and Environmental Studies, Yale University, Greeley Laboratories, New Haven, CT 06511, USA.
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Zimmermann MR, Felle HH. Dissection of heat-induced systemic signals: superiority of ion fluxes to voltage changes in substomatal cavities. PLANTA 2009; 229:539-547. [PMID: 19011895 DOI: 10.1007/s00425-008-0850-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2008] [Accepted: 10/21/2008] [Indexed: 05/27/2023]
Abstract
Using non-invasive ion-selective microprobes, that were placed in substomatal cavities, long-distance signalling has been investigated in intact Hordeum vulgare and Vicia faba seedlings. Heat (flame), applied to one leaf (S-leaf), triggers apoplastic ion activity (pH, pCa, pCl) transients in a distant leaf (T-leaf), all largely independent of simultaneously occurring action potential-like voltage changes. While apoplastic pCa and pH increase (Ca(2+)-, H(+)-activities decrease), pCl decreases (Cl(-)-activity increases). As the signal transfer from the S- to the T-leaf is too fast to account for mass flow, the heat-induced pressure change is primarily responsible for changes in voltage (H(+) pump deactivation) as well as for the ion fluxes. The pCa transient precedes the pCl- and pH responses, but not the voltage change. Since the apoplastic pCl decrease (Cl(-) increase) occurs after the pCa increase (Ca(2+) decrease) and after the depolarization, we argue that the Cl(-) efflux is a consequence of the Ca(2+) response, but has no part in the depolarization. Kinetic analysis reveals that pH- and pCl changes are interrelated, indicated by the action of the anion channel antagonist NPPB, which inhibits both pCl- and pH changes. It is suggested that efflux of organic anions into the apoplast causes the pH increase rather than the deactivation of the plasma membrane H(+) pump. Since there is considerably more information in ion activity changes than in a single action- or variation potential and heat-induced ion fluxes occur more reliably than voltage changes, released by milder stimuli, they are considered systemic signalling components superior to voltage.
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Affiliation(s)
- Mathias R Zimmermann
- Botanisches Institut I, Justus-Liebig-Universität, Senckenbergstrasse 17, 35390, Giessen, Germany
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Shepherd VA, Beilby MJ, Al Khazaaly SAS, Shimmen T. Mechano-perception in Chara cells: the influence of salinity and calcium on touch-activated receptor potentials, action potentials and ion transport. PLANT, CELL & ENVIRONMENT 2008; 31:1575-91. [PMID: 18684243 DOI: 10.1111/j.1365-3040.2008.01866.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
This paper investigates the impact of increased salinity on touch-induced receptor and action potentials of Chara internodal cells. We resolved underlying changes in ion transport by current/voltage analysis. In a saline medium with a low Ca(2+) ion concentration [(Ca(2+))(ext)], the cell background conductance significantly increased and proton pump currents declined to negligible levels, depolarizing the membrane potential difference (PD) to the excitation threshold [action potential (AP)(threshold)]. The onset of spontaneous repetitive action potentials further depolarized the PD, activating K(+) outward rectifying (KOR) channels. K(+) efflux was then sustained and irrevocable, and cells were desensitized to touch. However, when [Ca(2+)](ext) was high, the background conductance increased to a lesser extent and proton pump currents were stimulated, establishing a PD narrowly negative to AP(threshold). Cells did not spontaneously fire, but became hypersensitive to touch. Even slight touch stimulus induced an action potential and further repetitive firing. The duration of each excitation was extended when [Ca(2+)](ext) was low. Cell viability was prolonged in the absence of touch stimulus. Chara cells eventually depolarize and die in the saline media, but touch-stimulated and spontaneous excitation accelerates the process in a Ca(2+)-dependent manner. Our results have broad implications for understanding the interactions between mechano-perception and salinity stress in plants.
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Affiliation(s)
- Virginia A Shepherd
- Department of Biophysics, School of Physics, The University of New South Wales, Sydney, New South Wales 2052, Australia.
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Favre P, Agosti RD. Voltage-dependent action potentials in Arabidopsis thaliana. PHYSIOLOGIA PLANTARUM 2007; 131:263-72. [PMID: 18251897 DOI: 10.1111/j.1399-3054.2007.00954.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Voltage-elicited action potentials (APs) have been reproducibly obtained in Arabidopsis thaliana ecotype col. Excitations pulses (voltage-duration: V-t) were given in the 0- to 18-V and 0- to 35-s ranges, respectively, by two galvanically isolated Pt/Ir small wires inserted trough the main vein in the distal part of the leaf. Conventional liquid junction Ag/AgCl electrodes were placed at the zone between leaf/petiole (e1) and a second one on the petiole, near the central axis of the rosette (e2). A typical hyperbolic V-t relationship was obtained. The most excitable plants did have a chronaxy of 0.1 s and a rheobase of 2 V. Although the amplitude of the APs was highly variable (range 10-80 mV), it was related neither to the intensity nor to the duration of the stimulation pulse: the phenomenon is a typical all-or-none response. The APs were moving away from the excitation zone and could successively be detected at e1 and then at e2: their propagation speed was 1.15 +/- 0.26 mm s(-1). The absolute refractory period was approximately 20 min and the relative one approximately 80 min. The reproducibility of the voltage elicitation was in A. thaliana col ecotype 91%, with 83% of the APs propagating from the leaf to the petiole. In the Wassilewskija ecotype, 45% of the plants were responsive, with 78% of APs transmitted (propagation speed was 0.76 +/- 0.17 mm s(-1)), whereas in the Lansberg erecta ecotype none of the plant tested elicited a voltage-dependent AP.
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Affiliation(s)
- Patrick Favre
- Laboratory of Plant Physiology and Biochemistry, Plant Physiomatics, University of Geneva, 3 Place de l'Université, CH-1211 Geneva 4, Switzerland
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36
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Felle HH, Zimmermann MR. Systemic signalling in barley through action potentials. PLANTA 2007; 226:203-14. [PMID: 17226028 DOI: 10.1007/s00425-006-0458-y] [Citation(s) in RCA: 112] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2006] [Accepted: 11/23/2006] [Indexed: 05/13/2023]
Abstract
Using apoplastic voltage- and ion selective microprobes, in barley leaves action potentials (APs) have been measured, which propagate acropetally as well as basipetally from leaf to leaf or from root to leaf following the application of mild salt stress (e.g. 30-50 mM KCl or NH(4)Cl) or amino acids (e.g. 1 mM glutamic acid or 5 mM GABA). Voltage changes were biphasic, followed an 'all-or-none' characteristic, and propagated at 20-30 cm min(-1) irrespective of the direction. With the salt-induced APs, a strong initial depolarization is the main AP-releasing factor that first causes Ca(2+) influx and then anion efflux. Ca(2+) influx coincides with an initial slower depolarization, the rapid anion efflux causes the typical voltage 'break-through'. Subsequently, K(+)-efflux starts after the depolarizing voltage has passed the K(+) equilibrium potential (inversion of the K(+) driving force). Glutamic acid and GABA induce APs not through membrane depolarization, but presumably by binding to a putative receptor or to ligand-gated Ca(2+)-conducting channels, respectively, followed by Ca(2+) induced activation of anion efflux. APs are accompanied by transient apoplastic pH increase (about 1 unit), and by cytoplasmic pH decrease (about 0.5 units). The apoplastic pH change is interpreted as an indicator of stress, the cytoplasmic pH change as a prerequisite for defence related gene activation. Since APs are released by agents added in a moderate concentration range, it is suggested that they may serve as first and fast systemic signals following attack from pathogens.
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Affiliation(s)
- Hubert H Felle
- Botanisches Institut I, Justus-Liebig-Universität, Senckenbergstrasse 17, 35390, Giessen, Germany.
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Abstract
The plant action potential (AP) has been studied for more than half a century. The experimental system was provided mainly by the large charophyte cells, which allowed insertion of early large electrodes, manipulation of cell compartments, and inside and outside media. These early experiments were inspired by the Hodgkin and Huxley (HH) work on the squid axon and its voltage clamp techniques. Later, the patch clamping technique provided information about the ion transporters underlying the excitation transient. The initial models were also influenced by the HH picture of the animal AP. At the turn of the century, the paradigm of the charophyte AP shifted to include several chemical reactions, second messenger-activated channel, and calcium ion liberation from internal stores. Many aspects of this new model await further clarification. The role of the AP in plant movements, wound signaling, and turgor regulation is now well documented. Involvement in invasion by pathogens, chilling injury, light, and gravity sensing are under investigation.
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Affiliation(s)
- Mary Jane Beilby
- School of Physics, The University of New South Wales, Sydney, Australia
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Mancuso S, Marras AM. Adaptative response of Vitis root to anoxia. PLANT & CELL PHYSIOLOGY 2006; 47:401-9. [PMID: 16418229 DOI: 10.1093/pcp/pcj007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The effect of anoxia on the energy economy of root cells was studied by measuring heat production, ethanol and ATP production, K(+) fluxes and electrical activity in two Vitis species, V. riparia and V. rupestris, that differ in their tolerance to anoxia. Anoxia triggered a marked decrease of metabolic activity (measured by microcalorimetry) and of ATP levels in both species. In V. riparia after the first 2 h of anoxia, the decrease in the rate of heat production was not associated with a further significant decrease in ATP content, whereas in V. rupestris the ATP level continued to decrease until very low values were reached. The concomitant increase in the rate of ethanol production did not compensate for the decreased aerobic ATP supply. In V. rupestris, anoxia typically led to energy deficit and ATP imbalance, together with the subsequent disruption of ion homeostasis and cell death. In V. riparia, the strong decrease in K(+) membrane permeability together with the fast down-regulation of the electrical signals allowed the cells to avoid severe ion imbalances during prolonged anoxic episodes.
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Affiliation(s)
- Stefano Mancuso
- Laboratorio Internazionale di Neurobiologia Vegetale, Dipartimento di Ortoflorofrutticoltura, Polo Scientifico, Università di Firenze, Sesto F.no (FI), Italy.
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Stahlberg R. Historical overview on plant neurobiology. PLANT SIGNALING & BEHAVIOR 2006; 1:6-8. [PMID: 19521469 PMCID: PMC2633693 DOI: 10.4161/psb.1.1.2278] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2005] [Accepted: 10/26/2005] [Indexed: 05/18/2023]
Abstract
The review tracks the history of electrical long-distance signals from the first recordings of action potentials (APs) in sensitive Dionea and Mimosa plants at the end of the 19(th) century to their re-discovery in common plants in the 1950's, from the first intracellular recordings of APs in giant algal cells to the identification of the ionic mechanisms by voltage-clamp experiments. An important aspect is the comparison of plant and animal signals and the resulting theoretical implications that accompany the field from the first assignment of the term "action potential" to plants to recent discussions of terms like plant neurobiology.
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Michard E, Dreyer I, Lacombe B, Sentenac H, Thibaud JB. Inward rectification of the AKT2 channel abolished by voltage-dependent phosphorylation. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2005; 44:783-97. [PMID: 16297070 DOI: 10.1111/j.1365-313x.2005.02566.x] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
The Arabidopsis K(+) channel AKT2 possesses the remarkable property that its voltage threshold for activation can be either within the physiological range (gating mode 1), or shifted towards considerably more positive voltages (gating mode 2). Gating mode 1 AKT2 channels behave as delayed K(+)-selective inward rectifiers; while gating mode 2 AKT2 channels are K(+)-selective 'open leaks' in the physiological range of membrane potential. In the present study we have investigated modulation of AKT2 current by effectors of phosphatases/kinases in COS cells and Xenopus oocytes. These experiments show that (i) dephosphorylation can result in AKT2 channel silencing; and (ii) phosphorylation by protein kinase A (PKA) favors both recruitment of silenced AKT2 channels and transition from gating mode 1 to gating mode 2. Interestingly, phosphorylation of AKT2 by PKA in COS cells and Xenopus oocytes is favored by hyperpolarization. Two PKA phosphorylation sites (S210 and S329) were pinpointed in the region of the pore inner mouth. The role of these phosphorylation sites in the switch between the two gating modes was assessed by electrophysiological characterization of mutant channels. The molecular aspects of AKT2 regulation by phosphorylation, and the possible physiological meaning of such regulation in the plant context, are discussed.
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Affiliation(s)
- Erwan Michard
- Biochimie et Physiologie Moléculaire des Plantes, UMR5004 Agro.M-CNRS-INRA-UM2, Montpellier, France
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Manusadzianas L, Maksimov G, Darginaviciene J, Jurkoniene S, Sadauskas K, Vitkus R. Response of the charophyte Nitellopsis obtusa to heavy metals at the cellular, cell membrane, and enzyme levels. ENVIRONMENTAL TOXICOLOGY 2002; 17:275-283. [PMID: 12112636 DOI: 10.1002/tox.10058] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The responses of the freshwater macroalga Nitellopsis obtusa to heavy metal (HM) salts of Hg, Cd, Co, Cu, Cr, and Ni were assessed at different levels: whole-cell mortality (96-h LC(50)), in vivo cell membrane (45-min depolarization of resting potential, EC(50)), and enzyme in plasma membrane preparations (K+, Mg2+-specific H+-ATPase inhibition, IC(50)). To measure ATPase activity, a novel procedure for isolation of plasma membrane-enriched vesicles from charophyte cells was developed. The short-term ATPase inhibition assay (IC(50) from 6.0 x 10(-7) to 4.6 x 10(-4) M) was slightly more sensitive than the cell mortality test (LC(50) from 1.1 x 10(-6) to 2.6 x 10(-3) M), and the electrophysiological test with the end point of 45-min depolarization of resting potential was characterized by less sensitivity for HMs (EC(50) from 1.1 x 10(-4) to 2.2 x 10(-2) M). The variability of IC(50) values assessed for HMs in the ATPase assays was close to that of LC(50) values in the mortality tests (CVs from 33.5 to 83.5 and from 12.4% to 57.7%, respectively), whereas the EC(50) values in the electrophysiological tests were characterized by CVs generally below 30%. All three end points identified two separate HM groups according to their toxicity to N. obtusa: Co, Ni, and Cr comprised a group of less toxic metals, whereas Hg, Cu, and Cd comprised a group of more toxic metals. However, the adverse effects within each group were discriminated differently. For example, the maximum difference between the highest and lowest LC(50) for the group of less toxic metals in the long-term mortality test was approximately 60% of the response range, whereas the corresponding difference in IC(50) values in the ATPase assay was 30%. In contrast, the LC(50) values of the more toxic metals occupied only 10% of the response range, whereas the IC(50) values were spread over 70%. Further investigation should be done of the underlying mechanism or mechanisms responsible for the observed differences in the dynamic range of a particular end point of the groups of toxicants of varying strength.
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Mishra NS, Mallick BN, Sopory SK. Electrical signal from root to shoot in Sorghum bicolor: induction of leaf opening and evidence for fast extracellular propagation. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2001; 160:237-245. [PMID: 11164595 DOI: 10.1016/s0168-9452(00)00378-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We have observed earlier that primary leaf opening in Sorghum is a light-dependent process. We now show that giving a short photo-exposure to the roots alone also induced leaf opening over a similar time scale. However, any injury to the primary root inhibited the leaf formation. To check the propagation rate and response in this plant, the excitable properties and capability of conduction of electrical stimulus were investigated by extracellular recordings. Sorghum seedlings (5-7 days) were examined using non-damaging electrical stimuli. We demonstrate that seedlings when stimulated in one organ, the root region, produced a characteristic response, which could be recorded further up from the stimulating region in another organ, the shoot tissue. The minimum period of stimulation was 150 µs and threshold stimulus intensity was 100 µA. The general characteristic electrophysiological properties of the seedlings and the extracellular propagation of electrical signal suggest that S. bicolor exhibit typical excitable properties comparable to neural tissues. Moreover, electrical stimulus given to the root medium could overcome the requirement of photo-exposure to induce primary leaf formation in etiolated seedlings.
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Affiliation(s)
- N S. Mishra
- International Center for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, 110067, New Delhi, India
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Staves MP, Wayne R, Leopold AC. Detection of gravity-induced polarity of cytoplasmic streaming in Chara. PROTOPLASMA 1995; 188:38-48. [PMID: 11539183 DOI: 10.1007/bf01276794] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Gravity induces a polarity of cytoplasmic streaming in vertically-oriented internodal cells of characean algae. The motive force that powers cytoplasmic streaming is generated at the ectoplasmic/endoplasmic interface. The velocity of streaming, which is about 100 micrometers/s at this interface, decreases with distance from the interface on either side of the cell to 0 micrometers/s near the middle. Therefore, when discussing streaming velocity it is necessary to specify the tangential plane through the cell in which streaming is being measured. This is easily done with a moderate resolution light microscope (which has a lateral resolution of 0.6 micrometers and a depth of field of 1.4 micrometers), but is obscured when using any low resolution technique, such as low magnification light microscopy or laser Doppler spectroscopy. In addition, the effect of gravity on the polarity of cytoplasmic streaming declines with increasing physiological age of isolated cells. Using a classical mechanical analysis, we show that the effect of gravity on the polarity of cytoplasmic streaming cannot result from the effect of gravity acting directly on individual cytoplasmic particles. We suggest that gravity may best be perceived by the entire cell at the plasma membrane-extracellular matrix junction.
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Affiliation(s)
- M P Staves
- Section of Plant Biology and Boyce Thompson Institute, Cornell University, Ithaca, New York, USA
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