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Priego Espinosa D, Espinal-Enríquez J, Aldana A, Aldana M, Martínez-Mekler G, Carneiro J, Darszon A. Reviewing mathematical models of sperm signaling networks. Mol Reprod Dev 2024; 91:e23766. [PMID: 39175359 DOI: 10.1002/mrd.23766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2024] [Accepted: 07/22/2024] [Indexed: 08/24/2024]
Abstract
Dave Garbers' work significantly contributed to our understanding of sperm's regulated motility, capacitation, and the acrosome reaction. These key sperm functions involve complex multistep signaling pathways engaging numerous finely orchestrated elements. Despite significant progress, many parameters and interactions among these elements remain elusive. Mathematical modeling emerges as a potent tool to study sperm physiology, providing a framework to integrate experimental results and capture functional dynamics considering biochemical, biophysical, and cellular elements. Depending on research objectives, different modeling strategies, broadly categorized into continuous and discrete approaches, reveal valuable insights into cell function. These models allow the exploration of hypotheses regarding molecules, conditions, and pathways, whenever they become challenging to evaluate experimentally. This review presents an overview of current theoretical and experimental efforts to understand sperm motility regulation, capacitation, and the acrosome reaction. We discuss the strengths and weaknesses of different modeling strategies and highlight key findings and unresolved questions. Notable discoveries include the importance of specific ion channels, the role of intracellular molecular heterogeneity in capacitation and the acrosome reaction, and the impact of pH changes on acrosomal exocytosis. Ultimately, this review underscores the crucial importance of mathematical frameworks in advancing our understanding of sperm physiology and guiding future experimental investigations.
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Affiliation(s)
| | - Jesús Espinal-Enríquez
- Computational Genomics Division, National Institute of Genomic Medicine (INMEGEN), Mexico City, Mexico
| | - Andrés Aldana
- Network Science Institute, Northeastern University, Boston, Massachusetts, USA
| | - Maximino Aldana
- Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de México (UNAM), Mexico City, México
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Gustavo Martínez-Mekler
- Centro de Ciencias de la Complejidad, Universidad Nacional Autónoma de México (UNAM), Mexico City, México
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Cuernavaca, México
| | - Jorge Carneiro
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Alberto Darszon
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, México
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2
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Wan KY. Active oscillations in microscale navigation. Anim Cogn 2023; 26:1837-1850. [PMID: 37665482 PMCID: PMC10769930 DOI: 10.1007/s10071-023-01819-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 07/27/2023] [Accepted: 08/12/2023] [Indexed: 09/05/2023]
Abstract
Living organisms routinely navigate their surroundings in search of better conditions, more food, or to avoid predators. Typically, animals do so by integrating sensory cues from the environment with their locomotor apparatuses. For single cells or small organisms that possess motility, fundamental physical constraints imposed by their small size have led to alternative navigation strategies that are specific to the microscopic world. Intriguingly, underlying these myriad exploratory behaviours or sensory functions is the onset of periodic activity at multiple scales, such as the undulations of cilia and flagella, the vibrations of hair cells, or the oscillatory shape modes of migrating neutrophils. Here, I explore oscillatory dynamics in basal microeukaryotes and hypothesize that these active oscillations play a critical role in enhancing the fidelity of adaptive sensorimotor integration.
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Affiliation(s)
- Kirsty Y Wan
- Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK.
- Department of Mathematics and Statistics, University of Exeter, Stocker Road, Exeter, EX4 4QL, UK.
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3
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Quast T, Zölzer K, Guu D, Alvarez L, Küsters C, Kiermaier E, Kaupp UB, Kolanus W. A Stable Chemokine Gradient Controls Directional Persistence of Migrating Dendritic Cells. Front Cell Dev Biol 2022; 10:943041. [PMID: 36016652 PMCID: PMC9395945 DOI: 10.3389/fcell.2022.943041] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 06/21/2022] [Indexed: 11/13/2022] Open
Abstract
Navigation of dendritic cells (DCs) from the site of infection to lymphoid organs is guided by concentration gradients of CCR7 ligands. How cells interpret chemokine gradients and how they couple directional sensing to polarization and persistent chemotaxis has remained largely elusive. Previous experimental systems were limited in the ability to control fast de novo formation of the final gradient slope, long-lasting stability of the gradient and to expose cells to dynamic stimulation. Here, we used a combination of microfluidics and quantitative in vitro live cell imaging to elucidate the chemotactic sensing strategy of DCs. The microfluidic approach allows us to generate soluble gradients with high spatio-temporal precision and to analyze actin dynamics, cell polarization, and persistent directional migration in both static and dynamic environments. We demonstrate that directional persistence of DC migration requires steady-state characteristics of the soluble gradient instead of temporally rising CCL19 concentration, implying that spatial sensing mechanisms control chemotaxis of DCs. Kymograph analysis of actin dynamics revealed that the presence of the CCL19 gradient is essential to stabilize leading edge protrusions in DCs and to determine directionality, since both cytoskeletal polarization and persistent chemotaxis are abrogated in the range of seconds when steady-state gradients are perturbed. In contrast to Dictyostelium amoeba, DCs are unable to decode oscillatory stimulation of soluble chemokine traveling waves into a directional response toward the wave source. These findings are consistent with the notion that DCs do not employ adaptive temporal sensing strategies that discriminate temporally increasing and decreasing chemoattractant concentrations in our setting. Taken together, in our experimental system DCs do not depend on increasing absolute chemokine concentration over time to induce persistent migration and do not integrate oscillatory stimulation. The observed capability of DCs to migrate with high directional persistence in stable gradients but not when subjected to periodic temporal cues, identifies spatial sensing as a key requirement for persistent chemotaxis of DCs.
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Affiliation(s)
- Thomas Quast
- Molecular Immunology and Cell Biology, Life and Medical Sciences Institute (LIMES), University of Bonn, Bonn, Germany
| | - Karolin Zölzer
- Molecular Immunology and Cell Biology, Life and Medical Sciences Institute (LIMES), University of Bonn, Bonn, Germany
| | - Donald Guu
- Molecular Sensory Systems, Max Planck Institute for Neurobiology of Behavior—Caesar, Bonn, Germany
| | - Luis Alvarez
- Molecular Sensory Systems, Max Planck Institute for Neurobiology of Behavior—Caesar, Bonn, Germany
| | - Carsten Küsters
- Molecular Immunology and Cell Biology, Life and Medical Sciences Institute (LIMES), University of Bonn, Bonn, Germany
| | - Eva Kiermaier
- Immune and Tumor Biology, Life and Medical Sciences Institute (LIMES), University of Bonn, Bonn, Germany
| | - U. Benjamin Kaupp
- Molecular Sensory Systems, Max Planck Institute for Neurobiology of Behavior—Caesar, Bonn, Germany
| | - Waldemar Kolanus
- Molecular Immunology and Cell Biology, Life and Medical Sciences Institute (LIMES), University of Bonn, Bonn, Germany
- *Correspondence: Waldemar Kolanus,
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4
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Lange S, Friedrich BM. Sperm chemotaxis in marine species is optimal at physiological flow rates according theory of filament surfing. PLoS Comput Biol 2021; 17:e1008826. [PMID: 33844682 PMCID: PMC8041200 DOI: 10.1371/journal.pcbi.1008826] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 02/22/2021] [Indexed: 12/27/2022] Open
Abstract
Sperm of marine invertebrates have to find eggs cells in the ocean. Turbulent flows mix sperm and egg cells up to the millimeter scale; below this, active swimming and chemotaxis become important. Previous work addressed either turbulent mixing or chemotaxis in still water. Here, we present a general theory of sperm chemotaxis inside the smallest eddies of turbulent flow, where signaling molecules released by egg cells are spread into thin concentration filaments. Sperm cells ‘surf’ along these filaments towards the egg. External flows make filaments longer, but also thinner. These opposing effects set an optimal flow strength. The optimum predicted by our theory matches flow measurements in shallow coastal waters. Our theory quantitatively agrees with two previous fertilization experiments in Taylor-Couette chambers and provides a mechanistic understanding of these early experiments. ‘Surfing along concentration filaments’ could be a paradigm for navigation in complex environments in the presence of turbulent flow. Many motile cells navigate in complex environments along concentration gradients of signaling molecules. This chemotaxis has been studied extensively both experimentally and theoretically, yet mostly for idealized conditions of perfect chemical gradients. But under physiological conditions, concentration fields are subject to distortions, e.g., by turbulent flows in the ocean. Pioneering experiments suggest that in species with external fertilization, chemotaxis of sperm cells towards the egg may even work better at an optimal flow strength compared to conditions of still water. Yet to date, the mechanistic cause for this optimum is not known. We present a general theory of chemotactic navigation in external flow. We characterize how external flow distorts concentration fields into long filaments, and show how chemotaxing cells can subsequently ‘surf’ along these filaments towards a chemoattractant source. Stronger flows make concentration filaments longer, but also thinner; together, these two counter-acting effects set an optimal flow strength. Beyond fertilization of marine invertebrates, we believe that ‘surfing along concentration filaments’ could be a more general paradigm, relevant also for the ecology of marine bacteria feeding on organic marine snow in the ocean, or chemotaxis inside multi-cellular organisms with internal flows.
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Affiliation(s)
- Steffen Lange
- HTW Dresden, Dresden, Germany
- Center for Advancing Electronics Dresden, TU Dresden, Germany
- * E-mail:
| | - Benjamin M. Friedrich
- Center for Advancing Electronics Dresden, TU Dresden, Germany
- Cluster of Excellence Physics of Life, TU Dresden, Germany
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5
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Shabanniya MR, Naji A. Active dipolar spheroids in shear flow and transverse field: Population splitting, cross-stream migration, and orientational pinning. J Chem Phys 2020; 152:204903. [PMID: 32486664 DOI: 10.1063/5.0002757] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
We study the steady-state behavior of active, dipolar, Brownian spheroids in a planar channel subjected to an imposed Couette flow and an external transverse field, applied in the "downward" normal-to-flow direction. The field-induced torque on active spheroids (swimmers) is taken to be of magnetic form by assuming that they have a permanent magnetic dipole moment, pointing along their self-propulsion (swim) direction. Using a continuum approach, we show that a host of behaviors emerges over the parameter space spanned by the particle aspect ratio, self-propulsion and shear/field strengths, and the channel width. The cross-stream migration of the model swimmers is shown to involve a regime of linear response (quantified by a linear-response factor) in weak fields. For prolate swimmers, the weak-field behavior crosses over to a regime of full swimmer migration to the bottom half of the channel in strong fields. For oblate swimmers, a counterintuitive regime of reverse migration arises in intermediate fields, where a macroscopic fraction of swimmers reorient and swim to the top channel half at an acute "upward" angle relative to the field axis. The diverse behaviors reported here are analyzed based on the shear-induced population splitting (bimodality) of the swim orientation, giving two distinct, oppositely polarized, swimmer subpopulations (albeit very differently for prolate/oblate swimmers) in each channel half. In strong fields, swimmers of both types exhibit net upstream currents relative to the laboratory frame. The onsets of full migration and net upstream current depend on the aspect ratio, enabling efficient particle separation strategies in microfluidic setups.
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Affiliation(s)
- Mohammad Reza Shabanniya
- School of Physics, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran, Iran
| | - Ali Naji
- School of Physics, Institute for Research in Fundamental Sciences (IPM), P.O. Box 19395-5531, Tehran, Iran
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6
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Kromer JA, de la Cruz N, Friedrich BM. Chemokinetic Scattering, Trapping, and Avoidance of Active Brownian Particles. PHYSICAL REVIEW LETTERS 2020; 124:118101. [PMID: 32242704 DOI: 10.1103/physrevlett.124.118101] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 12/03/2019] [Accepted: 02/21/2020] [Indexed: 06/11/2023]
Abstract
We present a theory of chemokinetic search agents that regulate directional fluctuations according to distance from a target. A dynamic scattering effect reduces the probability to penetrate regions with high fluctuations and thus reduces search success for agents that respond instantaneously to positional cues. In contrast, agents with internal states that initially suppress chemokinesis can exploit scattering to increase their probability to find the target. Using matched asymptotics between the case of diffusive and ballistic search, we obtain analytic results beyond Fox colored noise approximation.
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Affiliation(s)
- Justus A Kromer
- Department of Neurosurgery, Stanford University, Palo Alto, California 94304, USA
| | - Noelia de la Cruz
- Department of Physics, McGill University, Montreal, Quebec H3A 2T8, Canada
| | - Benjamin M Friedrich
- cfaed, TU Dresden, 01069 Dresden, Germany
- Institute of Theoretical Physics, TU Dresden, 01069 Dresden, Germany
- Cluster of Excellence Physics of Life, TU Dresden, 01307 Dresden, Germany
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7
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Ramírez-Gómez HV, Jimenez Sabinina V, Velázquez Pérez M, Beltran C, Carneiro J, Wood CD, Tuval I, Darszon A, Guerrero A. Sperm chemotaxis is driven by the slope of the chemoattractant concentration field. eLife 2020; 9:50532. [PMID: 32149603 PMCID: PMC7093112 DOI: 10.7554/elife.50532] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 03/06/2020] [Indexed: 01/24/2023] Open
Abstract
Spermatozoa of marine invertebrates are attracted to their conspecific female gamete by diffusive molecules, called chemoattractants, released from the egg investments in a process known as chemotaxis. The information from the egg chemoattractant concentration field is decoded into intracellular Ca2+ concentration ([Ca2+]i) changes that regulate the internal motors that shape the flagellum as it beats. By studying sea urchin species-specific differences in sperm chemoattractant-receptor characteristics we show that receptor density constrains the steepness of the chemoattractant concentration gradient detectable by spermatozoa. Through analyzing different chemoattractant gradient forms, we demonstrate for the first time that Strongylocentrotus purpuratus sperm are chemotactic and this response is consistent with frequency entrainment of two coupled physiological oscillators: i) the stimulus function and ii) the [Ca2+]i changes. We demonstrate that the slope of the chemoattractant gradients provides the coupling force between both oscillators, arising as a fundamental requirement for sperm chemotaxis.
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Affiliation(s)
- Héctor Vicente Ramírez-Gómez
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mexico
| | - Vilma Jimenez Sabinina
- Cell Biology and Biophysics Unit, European Molecular Biology Laboratory (EMBL), Heidelberg, Germany
| | - Martín Velázquez Pérez
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mexico
| | - Carmen Beltran
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mexico
| | - Jorge Carneiro
- Instituto Gulbenkian de Ciência (IGC), Rua da Quinta Grande, Oeiras, Portugal
| | - Christopher D Wood
- Laboratorio Nacional de Microscopía Avanzada, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mexico
| | - Idan Tuval
- Mediterranean Institute for Advanced Studies, IMEDEA (CSIC-UIB), Esporles, Spain.,Department of Physics, University of the Balearic Islands, Palma, Spain
| | - Alberto Darszon
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mexico
| | - Adán Guerrero
- Laboratorio Nacional de Microscopía Avanzada, Instituto de Biotecnología, Universidad Nacional Autónoma de México (UNAM), Cuernavaca, Mexico
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8
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Priego-Espinosa DA, Darszon A, Guerrero A, González-Cota AL, Nishigaki T, Martínez-Mekler G, Carneiro J. Modular analysis of the control of flagellar Ca2+-spike trains produced by CatSper and CaV channels in sea urchin sperm. PLoS Comput Biol 2020; 16:e1007605. [PMID: 32119665 PMCID: PMC7067495 DOI: 10.1371/journal.pcbi.1007605] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 03/12/2020] [Accepted: 12/13/2019] [Indexed: 11/18/2022] Open
Abstract
Intracellular calcium ([Ca2+]i) is a basic and ubiquitous cellular signal controlling a wide variety of biological processes. A remarkable example is the steering of sea urchin spermatozoa towards the conspecific egg by a spatially and temporally orchestrated series of [Ca2+]i spikes. Although this process has been an experimental paradigm for reproduction and sperm chemotaxis studies, the composition and regulation of the signalling network underlying the cytosolic calcium fluctuations are hitherto not fully understood. Here, we used a differential equations model of the signalling network to assess which set of channels can explain the characteristic envelope and temporal organisation of the [Ca2+]i-spike trains. The signalling network comprises an initial membrane hyperpolarisation produced by an Upstream module triggered by the egg-released chemoattractant peptide, via receptor activation, cGMP synthesis and decay. Followed by downstream modules leading to intraflagellar pH (pHi), voltage and [Ca2+]i fluctuations. The Upstream module outputs were fitted to kinetic data on cGMP activity and early membrane potential changes measured in bulk cell populations. Two candidate modules featuring voltage-dependent Ca2+-channels link these outputs to the downstream dynamics and can independently explain the typical decaying envelope and the progressive spacing of the spikes. In the first module, [Ca2+]i-spike trains require the concerted action of a classical CaV-like channel and a potassium channel, BK (Slo1), whereas the second module relies on pHi-dependent CatSper dynamics articulated with voltage-dependent neutral sodium-proton exchanger (NHE). We analysed the dynamics of these two modules alone and in mixed scenarios. We show that the [Ca2+]i dynamics observed experimentally after sustained alkalinisation can be reproduced by a model featuring the CatSper and NHE module but not by those including the pH-independent CaV and BK module or proportionate mixed scenarios. We conclude in favour of the module containing CatSper and NHE and highlight experimentally testable predictions that would corroborate this conclusion. Fertilisation in marine invertebrates, such as the sea urchin, occurs during broadcast spawning events in which males and females of co-localised species ejaculate sperm and spawn eggs synchronously. During these events, spermatozoa have to find and fertilise conspecific eggs in the midst of all the other ones, which is a remarkable navigation and mating choice achievement. Sperm cells do this by navigating towards the source of species-specific peptides released by the egg, steered by spatial and temporally orchestrated peaks in intracellular calcium concentration that trigger sudden reorientations. How these calcium spikes are regulated and timed remains elusive. Different calcium channels have been implicated by indirect experimental evidence giving rise to a complex network of putative interacting components. We gained insight into the structure and function of this network by modelling it as a set of candidate modules that could be studied separately. By using this ‘divide and conquer’ approach to the complexity of the network, we could characterise the potential dynamics of each module and confront these dynamics with specific quantitative data. Our results indicate that the channel mediating calcium signals in sea urchin sperm is likely CatSper, a calcium channel necessary for human male fertility.
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Affiliation(s)
| | - Alberto Darszon
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
| | - Adán Guerrero
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Ana Laura González-Cota
- Washington University School of Medicine, Department of Obstetrics and Gynecology, Center for Reproductive Health Sciences, St. Louis, Missouri, United States of America
| | - Takuya Nishigaki
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
| | - Gustavo Martínez-Mekler
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
- Centro de Ciencias de la Complejidad UNAM, CDMX, México
- Laboratoire de Physique Statistique, Départment de Physique, Ecole Normale Supérieure, Paris, France
- * E-mail: (GMM); (JC)
| | - Jorge Carneiro
- Instituto Gulbenkian de Ciência, Oeiras, Portugal
- * E-mail: (GMM); (JC)
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9
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Hamzeh H, Alvarez L, Strünker T, Kierzek M, Brenker C, Deal PE, Miller EW, Seifert R, Kaupp UB. Kinetic and photonic techniques to study chemotactic signaling in sea urchin sperm. Methods Cell Biol 2019; 151:487-517. [PMID: 30948028 DOI: 10.1016/bs.mcb.2018.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Sperm from sea urchins are attracted by chemical cues released by the egg-a mechanism called chemotaxis. We describe here the signaling pathway and molecular components endowing sperm with single-molecule sensitivity. Chemotactic signaling and behavioral responses occur on a timescale of a few milliseconds to seconds. We describe the techniques and chemical tools used to resolve the signaling events in time. The techniques include rapid-mixing devices, rapid stroboscopic microscopy, and photolysis of caged second messengers and chemoattractants.
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Affiliation(s)
- Hussein Hamzeh
- Department of Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), Bonn, Germany
| | - Luis Alvarez
- Department of Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), Bonn, Germany
| | - Timo Strünker
- Center of Reproductive Medicine and Andrology, University Hospital Münster, University of Münster, Münster, Germany
| | - Michelina Kierzek
- Center of Reproductive Medicine and Andrology, University Hospital Münster, University of Münster, Münster, Germany
| | - Christoph Brenker
- Center of Reproductive Medicine and Andrology, University Hospital Münster, University of Münster, Münster, Germany
| | - Parker E Deal
- Department of Chemistry, University of California, Berkeley, CA, United States
| | - Evan W Miller
- Department of Chemistry, University of California, Berkeley, CA, United States; Department of Molecular & Cell Biology, University of California, Berkeley, CA, United States; Helen Wills Neuroscience Institute, University of California, Berkeley, CA, United States
| | - Reinhard Seifert
- Department of Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), Bonn, Germany
| | - U Benjamin Kaupp
- Department of Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), Bonn, Germany.
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10
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Maity R, Burada PS. A hydrodynamic-stochastic model of chemotactic ciliated microorganisms. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2019; 42:20. [PMID: 30788619 DOI: 10.1140/epje/i2019-11780-4] [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: 04/25/2018] [Accepted: 01/10/2019] [Indexed: 06/09/2023]
Abstract
Biological systems like ciliated microorganisms are capable of responding to the external chemical gradients, a process known as chemotaxis. In this process, the internal signaling network of the microorganism is triggered due to binding of the chemoattractant molecules with the receptors on the surface of the body. This can alter the activity at the surface of the microorganism. We study the chemotaxis of ciliated microorganisms using the chiral squirmer model, a spherical body with a surface slip velocity. In the presence of a chemical gradient, the coefficients of the slip velocity get modified resulting in a change in the path followed by the body. We observe that the strength of the gradient is not the only parameter which controls the dynamics of the body but also the adaptation time plays a very significant role in the success of chemotaxis. The trajectory of the body is smooth if we ignore the discreteness in the ligand-receptor binding which is stochastic in nature. In the presence of the latter, the path is not only irregular but the whole dynamics of the body changes. We calculate the mean first passage time, by varying the strength of the chemical gradient and the adaptation time, to determine the success rate of chemotaxis.
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Affiliation(s)
- Ruma Maity
- Department of Physics, Indian Institute of Technology Kharagpur, Kharagpur, India
| | - P S Burada
- Department of Physics, Indian Institute of Technology Kharagpur, Kharagpur, India.
- Center for Theoretical Studies, Indian Institute of Technology Kharagpur, Kharagpur, India.
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11
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Kromer JA, Märcker S, Lange S, Baier C, Friedrich BM. Decision making improves sperm chemotaxis in the presence of noise. PLoS Comput Biol 2018; 14:e1006109. [PMID: 29672515 PMCID: PMC5929576 DOI: 10.1371/journal.pcbi.1006109] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 05/01/2018] [Accepted: 03/23/2018] [Indexed: 01/13/2023] Open
Abstract
To navigate their surroundings, cells rely on sensory input that is corrupted by noise. In cells performing chemotaxis, such noise arises from the stochastic binding of signalling molecules at low chemoattractant concentrations. We reveal a fundamental relationship between the speed of chemotactic steering and the strength of directional fluctuations that result from the amplification of noise in a chemical input signal. This relation implies a trade-off between steering that is slow and reliable, and steering that is fast but less reliable. We show that dynamic switching between these two modes of steering can substantially increase the probability to find a target, such as an egg to be found by sperm cells. This decision making confers no advantage in the absence of noise, but is beneficial when chemical signals are detectable, yet characterized by low signal-to-noise ratios. The latter applies at intermediate distances from a target, where signalling molecules are diluted, thus defining a ‘noise zone’ that cells have to cross. Our results explain decision making observed in recent experiments on sea urchin sperm chemotaxis. More generally, our theory demonstrates how decision making enables chemotactic agents to cope with high levels of noise in gradient sensing by dynamically adjusting the persistence length of a biased random walk. Many cells can navigate upwards a concentration gradient of signalling molecules, a process called chemotaxis. Chemotaxis is used e.g. by sperm cells to find the egg. To measure and compare concentrations, cells count stochastic binding events of signalling molecules that diffuse to cellular receptors. Efficient chemotaxis strategies must be adapted to this molecular shot noise of concentration measurements. We reveal a fundamental relationship between the speed of chemotactic steering and the strength of directional fluctuations that result from the amplification of noise. This implies a trade-off between steering fast and steering reliable. Inspired by recent experiments on chemotaxis of sperm cells of marine invertebrates, we develop a theory that allows to efficiently compute optimal chemotaxis strategies. We show that dynamic switching between either fast or reliable steering can substantially increase the probability for a sperm cell to find the egg. Furthermore, the optimal strategy requires only minimal computational capacities of the chemotactic agent, a key constraint for biological cells. More generally, our work demonstrates a benefit of decision making for chemotaxis in the presence of noise, which could inspire optimal control designs for artificial microswimmers.
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Affiliation(s)
| | - Steffen Märcker
- Faculty of Computer Science, TU Dresden, Dresden, Sachsen, Germany
| | | | - Christel Baier
- Faculty of Computer Science, TU Dresden, Dresden, Sachsen, Germany
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12
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Tan RZ, Chiam KH. A computational model for how cells choose temporal or spatial sensing during chemotaxis. PLoS Comput Biol 2018; 14:e1005966. [PMID: 29505572 PMCID: PMC5854446 DOI: 10.1371/journal.pcbi.1005966] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 03/15/2018] [Accepted: 01/10/2018] [Indexed: 12/24/2022] Open
Abstract
Cell size is thought to play an important role in choosing between temporal and spatial sensing in chemotaxis. Large cells are thought to use spatial sensing due to large chemical difference at its ends whereas small cells are incapable of spatial sensing due to rapid homogenization of proteins within the cell. However, small cells have been found to polarize and large cells like sperm cells undergo temporal sensing. Thus, it remains an open question what exactly governs spatial versus temporal sensing. Here, we identify the factors that determines sensing choices through mathematical modeling of chemotactic circuits. Comprehensive computational search of three-node signaling circuits has identified the negative integral feedback (NFB) and incoherent feedforward (IFF) circuits as capable of adaptation, an important property for chemotaxis. Cells are modeled as one-dimensional circular system consisting of diffusible activator, inactivator and output proteins, traveling across a chemical gradient. From our simulations, we find that sensing outcomes are similar for NFB or IFF circuits. Rather than cell size, the relevant parameters are the 1) ratio of cell speed to the product of cell diameter and rate of signaling, 2) diffusivity of the output protein and 3) ratio of the diffusivities of the activator to inactivator protein. Spatial sensing is favored when all three parameters are low. This corresponds to a cell moving slower than the time it takes for signaling to propagate across the cell diameter, has an output protein that is polarizable and has a local-excitation global-inhibition system to amplify the chemical gradient. Temporal sensing is favored otherwise. We also find that temporal sensing is more robust to noise. By performing extensive literature search, we find that our prediction agrees with observation in a wide range of species and cell types ranging from E. coli to human Fibroblast cells and propose that our result is universally applicable. Unicellular organisms and other single cells often have to migrate towards food sources or away from predators by sensing chemicals present in the environment. There are two ways for a cell to sense these external chemicals: temporal sensing, where the cell senses the external chemical at two different time points after it has moved through a certain distance, or spatial sensing, where the cell senses the external chemical at two different locations on its cellular surface (e.g., the front and rear of the cell) simultaneously. It has been thought that small unicellular organisms employ temporal sensing as their small size prohibits sensing at two different locations on the cellular surface. Using computational modeling, we find that the choice between temporal and spatial sensing is determined by the ratio of cell velocity to the product of cell diameter and rate of signaling, as well as the diffusivities of the signaling proteins. Predictions from our model agree with experimental observations over a wide range of cells, where a fast-moving, small cell performs better comparing the chemoattractant at different times in its trajectory; whereas, a slow-moving, big cell performs better by comparing the chemoattractant concentration at its two ends.
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13
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Gervasi MG, Visconti PE. Chang's meaning of capacitation: A molecular perspective. Mol Reprod Dev 2018; 83:860-874. [PMID: 27256723 DOI: 10.1002/mrd.22663] [Citation(s) in RCA: 101] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 05/31/2016] [Indexed: 02/04/2023]
Abstract
Dr. Min Chue Chang's contributions to the field of reproductive biology set the stage for the development of the contraceptive pill and in vitro fertilization. Throughout his publications, Dr. Chang was also able to transmit his view of the fertilization process in ways that organized research for newer generations of reproductive biologists. Particularly relevant for the achievement of in vitro fertilization in mammals was the discovery that the sperm required a period of residence in the female tract to become fertilization-competent; Dr. Chang and Dr. Austin, in Australia, independently reported this process, now known as sperm capacitation. This review discusses Dr. Chang's views on capacitation, and puts them in the context of recent advances in the understanding of the molecular basis of this process. Mol. Reprod. Dev. 83: 860-874, 2016 © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Maria Gracia Gervasi
- Department of Veterinary and Animal Sciences, ISB, University of Massachusetts, Amherst, Massachusetts
| | - Pablo E Visconti
- Department of Veterinary and Animal Sciences, ISB, University of Massachusetts, Amherst, Massachusetts.
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14
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Foo SA, Deaker D, Byrne M. Cherchez la femme - impact of ocean acidification on the egg jelly coat and attractants for sperm. J Exp Biol 2018; 221:jeb.177188. [DOI: 10.1242/jeb.177188] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 04/16/2018] [Indexed: 01/03/2023]
Abstract
The impact of ocean acidification on marine invertebrate eggs and consequences for sperm chemotaxis are unknown. In the sea urchins Heliocidaris tuberculata and H. erythrogramma, with small (93µm) and large (393µm) eggs, respectively, we documented the effect of decreased pH on the egg jelly coat, an extracellular matrix that increases target size for sperm and contains sperm attracting molecules. In near future conditions (pH 7.8, 7.6) the jelly coat of H. tuberculata decreased by 11 and 21%, reducing egg target size by 9 and 17%, respectively. In contrast, the egg jelly coat of H. erythrogramma was not affected. The reduction in the jelly coat has implications for sperm chemotaxis in H. tuberculata. In the presence of decreased pH and egg chemicals, the sperm of this species increased their velocity, motility and linearity, behaviour that was opposite to that seen for sperm exposed to egg chemicals in ambient conditions. Egg chemistry appears to cause a reduction in sperm velocity where attractants guide them in the direction of the egg. Investigation of the effects of decreased pH on sperm isolated from egg chemistry does not provide an integrative assessment of the effects of ocean acidification on sperm function. Differences in the sensitivity of the jelly coat of the two species is likely associated with egg evolution in H. erythrogramma. We highlight important unappreciated impacts of ocean acidification on marine gamete functionality, and insights into potential winners and losers in a changing ocean, pointing to the advantage conveyed by evolution of large eggs.
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Affiliation(s)
- Shawna A. Foo
- Department of Global Ecology, Carnegie Institution for Science, Stanford, CA, USA
| | - Dione Deaker
- School of Medical Sciences, The University of Sydney, Sydney, New South Wales, Australia
| | - Maria Byrne
- School of Medical Sciences and School of Life and Environmental Sciences, The University of Sydney, Sydney, New South Wales, Australia
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15
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Iida T, Iwata Y, Mohri T, Baba SA, Hirohashi N. A coordinated sequence of distinct flagellar waveforms enables a sharp flagellar turn mediated by squid sperm pH-taxis. Sci Rep 2017; 7:12938. [PMID: 29021593 PMCID: PMC5636881 DOI: 10.1038/s41598-017-13406-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 09/22/2017] [Indexed: 11/20/2022] Open
Abstract
Animal spermatozoa navigate by sensing ambient chemicals to reach the site of fertilization. Generally, such chemicals derive from the female reproductive organs or cells. Exceptionally, squid spermatozoa mutually release and perceive carbon dioxide to form clusters after ejaculation. We previously identified the pH-taxis by which each spermatozoon can execute a sharp turn, but how flagellar dynamics enable this movement remains unknown. Here, we show that initiation of the turn motion requires a swim down a steep proton gradient (a theoretical estimation of ≥0.025 pH/s), crossing a threshold pH value of ~5.5. Time-resolved kinematic analysis revealed that the turn sequence results from the rhythmic exercise of two flagellar motions: a stereotypical flagellar ‘bent-cane’ shape followed by asymmetric wave propagation, which enables a sharp turn in the realm of low Reynolds numbers. This turning episode is terminated by an ‘overshoot’ trajectory that differs from either straight-line motility or turning. As with bidirectional pH-taxes in some bacteria, squid spermatozoa also showed repulsion from strong acid conditions with similar flagellar kinematics as in positive pH-taxis. These findings indicate that squid spermatozoa might have a unique reorientation mechanism, which could be dissimilar to that of classical egg-guided sperm chemotaxis in other marine invertebrates.
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Affiliation(s)
- Tomohiro Iida
- Oki Marine Biological Station, Education and Research Center for Biological Resources, Shimane University, 194 Kamo, Okinoshima-cho, Oki, Shimane, 685-0024, Japan
| | - Yoko Iwata
- Atmosphere and Ocean Research Institute, University of Tokyo, Kashiwa, Japan
| | - Tatsuma Mohri
- Section of Individual Researches, National Institute for Physiological Sciences, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji-cho Okazaki, 444-8787, Japan
| | - Shoji A Baba
- Ochanomizu University, 2-2-1 Otsuka, Tokyo, 112-8610, Japan
| | - Noritaka Hirohashi
- Oki Marine Biological Station, Education and Research Center for Biological Resources, Shimane University, 194 Kamo, Okinoshima-cho, Oki, Shimane, 685-0024, Japan.
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16
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Niksirat H, Andersson L, Golpour A, Chupani L, James P. Quantification of egg proteome changes during fertilization in sterlet Acipenser ruthenus. Biochem Biophys Res Commun 2017; 490:189-193. [DOI: 10.1016/j.bbrc.2017.06.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2017] [Accepted: 06/02/2017] [Indexed: 11/25/2022]
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17
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Hussain YH, Sadilek M, Salad S, Zimmer RK, Riffell JA. Individual female differences in chemoattractant production change the scale of sea urchin gamete interactions. Dev Biol 2017; 422:186-197. [PMID: 28088316 DOI: 10.1016/j.ydbio.2017.01.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2016] [Revised: 01/02/2017] [Accepted: 01/10/2017] [Indexed: 01/13/2023]
Abstract
Sperm selection by females is an important process influencing fertilization and, particularly in broadcast-spawning organisms, often occurs before sperm reach the egg. Waterborne sperm chemoattractants are one mechanism by which eggs selectively influence conspecific sperm behavior, but it remains an open question whether the eggs from different females produce different amounts of sperm chemoattractant, and how that might influence sperm behavior. Here, we quantify the differences in attractant production between females of the sea urchin species Lytechinus pictus and use computational models and microfluidic sperm chemotaxis assays to determine how differences in chemoattractant production between females affects their ability to attract sperm. Our study demonstrates that there is significant individual female variation in egg chemoattractant production, and that this variation changes the scope and strength of sperm attraction. These results provide evidence for the importance of individual female variability in differential sperm attraction and fertilization success.
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Affiliation(s)
- Yasmeen H Hussain
- University of Washington, Department of Biology, Seattle, WA 98195, USA
| | - Martin Sadilek
- University of Washington, Department of Chemistry, Seattle, WA 98195, USA
| | - Shukri Salad
- University of Washington, Department of Biology, Seattle, WA 98195, USA
| | - Richard K Zimmer
- University of California Los Angeles, Department of Ecology and Evolutionary Biology, Los Angeles, CA 90095, USA
| | - Jeffrey A Riffell
- University of Washington, Department of Biology, Seattle, WA 98195, USA
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18
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Richards DM, Saunders TE. Spatiotemporal analysis of different mechanisms for interpreting morphogen gradients. Biophys J 2016; 108:2061-73. [PMID: 25902445 DOI: 10.1016/j.bpj.2015.03.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2014] [Revised: 03/05/2015] [Accepted: 03/10/2015] [Indexed: 10/23/2022] Open
Abstract
During development, multicellular organisms must accurately control both temporal and spatial aspects of tissue patterning. This is often achieved using morphogens, signaling molecules that form spatially varying concentrations and so encode positional information. Typical analysis of morphogens assumes that spatial information is decoded in steady state by measuring the value of the morphogen concentration. However, recent experimental work suggests that both pre-steady-state readout and measurement of spatial and temporal derivatives of the morphogen concentration can play important roles in defining boundaries. Here, we undertake a detailed theoretical and numerical study of the accuracy of patterning-both in space and time-in models where readout is provided not by the morphogen concentration but by its spatial and temporal derivatives. In both cases we find that accurate patterning can be achieved, with sometimes even smaller errors than directly reading the morphogen concentration. We further demonstrate that such models provide other potential benefits to the system, such as the ability to switch on and off gene response with a high degree of spatiotemporal accuracy. Finally, we discuss how such derivatives might be calculated biologically and examine these models in relation to Sonic Hedgehog signaling in the vertebrate central nervous system. We show that, when coupled to a downstream transcriptional network, pre-steady-state measurement of the temporal change in the Shh morphogen is a plausible mechanism for determining precise gene boundaries in both space and time.
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Affiliation(s)
- David M Richards
- Department of Life Sciences, Imperial College, London, United Kingdom.
| | - Timothy E Saunders
- Mechanobiology Institute, National University of Singapore, Singapore; Department of Biological Sciences, National University of Singapore, Singapore; Institute of Molecular and Cell Biology, Agency for Science Technology and Research, Singapore.
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19
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Fechner S, Alvarez L, Bönigk W, Müller A, Berger TK, Pascal R, Trötschel C, Poetsch A, Stölting G, Siegfried KR, Kremmer E, Seifert R, Kaupp UB. A K(+)-selective CNG channel orchestrates Ca(2+) signalling in zebrafish sperm. eLife 2015; 4:e07624. [PMID: 26650356 PMCID: PMC4749565 DOI: 10.7554/elife.07624] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Accepted: 12/09/2015] [Indexed: 01/03/2023] Open
Abstract
Calcium in the flagellum controls sperm navigation. In sperm of marine invertebrates and mammals, Ca(2+) signalling has been intensely studied, whereas for fish little is known. In sea urchin sperm, a cyclic nucleotide-gated K(+) channel (CNGK) mediates a cGMP-induced hyperpolarization that evokes Ca(2+) influx. Here, we identify in sperm of the freshwater fish Danio rerio a novel CNGK family member featuring non-canonical properties. It is located in the sperm head rather than the flagellum and is controlled by intracellular pH, but not cyclic nucleotides. Alkalization hyperpolarizes sperm and produces Ca(2+) entry. Ca(2+) induces spinning-like swimming, different from swimming of sperm from other species. The "spinning" mode probably guides sperm into the micropyle, a narrow entrance on the surface of fish eggs. A picture is emerging of sperm channel orthologues that employ different activation mechanisms and serve different functions. The channel inventories probably reflect adaptations to species-specific challenges during fertilization.
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Affiliation(s)
- Sylvia Fechner
- Abteilung Molekulare Neurosensorik, Center of Advanced European Studies and Research, Bonn, Germany
| | - Luis Alvarez
- Abteilung Molekulare Neurosensorik, Center of Advanced European Studies and Research, Bonn, Germany
| | - Wolfgang Bönigk
- Abteilung Molekulare Neurosensorik, Center of Advanced European Studies and Research, Bonn, Germany
| | - Astrid Müller
- Abteilung Molekulare Neurosensorik, Center of Advanced European Studies and Research, Bonn, Germany
| | - Thomas K Berger
- Abteilung Molekulare Neurosensorik, Center of Advanced European Studies and Research, Bonn, Germany
| | - Rene Pascal
- Abteilung Molekulare Neurosensorik, Center of Advanced European Studies and Research, Bonn, Germany
| | | | - Ansgar Poetsch
- Lehrstuhl Biochemie der Pflanzen, Ruhr-Universität Bochum, Bochum, Germany
| | - Gabriel Stölting
- Institute of Complex Systems 4, Forschungszentrum Jülich, Jülich, Germany
| | - Kellee R Siegfried
- Biology Department, University of Massachusetts Boston, Boston, United States
| | - Elisabeth Kremmer
- Institut für Molekulare Immunologie, Helmholtz-Zentrum München, München, Germany
| | - Reinhard Seifert
- Abteilung Molekulare Neurosensorik, Center of Advanced European Studies and Research, Bonn, Germany
| | - U Benjamin Kaupp
- Abteilung Molekulare Neurosensorik, Center of Advanced European Studies and Research, Bonn, Germany
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20
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Jikeli JF, Alvarez L, Friedrich BM, Wilson LG, Pascal R, Colin R, Pichlo M, Rennhack A, Brenker C, Kaupp UB. Sperm navigation along helical paths in 3D chemoattractant landscapes. Nat Commun 2015; 6:7985. [PMID: 26278469 PMCID: PMC4557273 DOI: 10.1038/ncomms8985] [Citation(s) in RCA: 110] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 07/02/2015] [Indexed: 12/17/2022] Open
Abstract
Sperm require a sense of direction to locate the egg for fertilization. They follow gradients of chemical and physical cues provided by the egg or the oviduct. However, the principles underlying three-dimensional (3D) navigation in chemical landscapes are unknown. Here using holographic microscopy and optochemical techniques, we track sea urchin sperm navigating in 3D chemoattractant gradients. Sperm sense gradients on two timescales, which produces two different steering responses. A periodic component, resulting from the helical swimming, gradually aligns the helix towards the gradient. When incremental path corrections fail and sperm get off course, a sharp turning manoeuvre puts sperm back on track. Turning results from an ‘off' Ca2+ response signifying a chemoattractant stimulation decrease and, thereby, a drop in cyclic GMP concentration and membrane voltage. These findings highlight the computational sophistication by which sperm sample gradients for deterministic klinotaxis. We provide a conceptual and technical framework for studying microswimmers in 3D chemical landscapes. Sperm use external cues to find the egg using ill-defined principles. Here the authors use holographic microscopy and optochemical tools to study sperm swimming in light-sculpted chemical 3D landscapes; they show that sperm translate the temporal stimulation pattern into multiple swimming behaviours to orient deterministically in a gradient.
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Affiliation(s)
- Jan F Jikeli
- Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Luis Alvarez
- Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Benjamin M Friedrich
- Biological Physics, Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, 01187 Dresden, Germany
| | - Laurence G Wilson
- Department of Physics, University of York, YO10 5DD Heslington, York, UK
| | - René Pascal
- Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Remy Colin
- Max Planck Institute for Terrestrial Microbiology, Karl-von-Frisch Straße 16, 35043 Marburg, Germany
| | - Magdalena Pichlo
- Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Andreas Rennhack
- Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Christoph Brenker
- Centre of Reproductive Medicine and Andrology, University of Muenster, 48149 Muenster, Germany
| | - U Benjamin Kaupp
- Molecular Sensory Systems, Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
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21
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Strünker T, Alvarez L, Kaupp UB. At the physical limit - chemosensation in sperm. Curr Opin Neurobiol 2015; 34:110-6. [PMID: 25768273 DOI: 10.1016/j.conb.2015.02.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 02/18/2015] [Accepted: 02/18/2015] [Indexed: 12/15/2022]
Abstract
Many cells probe their environment for chemical cues. Some cells respond to picomolar concentrations of neuropeptides, hormones, pheromones, or chemoattractants. At such low concentrations, cells encounter only a few molecules. The mechanistic underpinnings of single-molecule sensitivity are not known for any eukaryotic cell. Sea urchin sperm offer a unique model to unveil in quantitative terms the principles underlying chemosensation at the physical limit. Here, we discuss the mechanisms of such exquisite sensitivity and the computational operations performed by sperm during chemotactic steering. Moreover, we highlight commonalities and differences between signalling in sperm and photoreceptors and among sperm from different species.
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Affiliation(s)
- T Strünker
- Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, Bonn 53175, Germany
| | - L Alvarez
- Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, Bonn 53175, Germany
| | - U B Kaupp
- Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, Bonn 53175, Germany.
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22
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Miyashiro D, Shiba K, Miyashita T, Baba SA, Yoshida M, Kamimura S. Chemotactic response with a constant delay-time mechanism in Ciona spermatozoa revealed by a high time resolution analysis of flagellar motility. Biol Open 2015; 4:109-18. [PMID: 25572419 PMCID: PMC4365479 DOI: 10.1242/bio.20137351] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 11/07/2014] [Indexed: 01/05/2023] Open
Abstract
During their chemotactic swimming toward eggs, sperm cells detect their species-specific chemoattractant and sense concentration gradients by unknown mechanisms. After sensing the attractant, sperm cells commonly demonstrate a series of responses involving different swimming patterns by changing flagellar beats, gradually approaching a swimming path toward the eggs, which is the source of chemoattractants. Shiba et al. observed a rapid increase in intracellular Ca(2+) concentrations in Ciona spermatozoa after sensing chemoattractants; however, the biochemical processes occurring inside the sperm cells are unclear. In the present study, we focused on the timing and sensing mechanism of chemical signal detection in Ciona. One of the most crucial problems to be solved is defining the initial epoch of chemotactic responses. We adopted a high rate of video recording (600 Hz) for detailed analysis of sperm motion and a novel method for detecting subtle signs of beat forms and moving paths of sperm heads. From these analyses, we estimated a virtual sensing point of the attractant before initiation of motility responses and found that the time delay from sensing to motility responses was almost constant. To evaluate the efficiency of this constant delay model, we performed computer simulation of chemotactic behaviors of Ciona spermatozoa.
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Affiliation(s)
- Daisuke Miyashiro
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo 153-8902, Japan
| | - Kogiku Shiba
- Shimoda Marine Research Center, University of Tsukuba, Shizuoka 415-0025, Japan
| | - Tahahiro Miyashita
- Department of Biological Sciences, Faculty of Science and Engineering, Chuo University, Tokyo 112-8551, Japan
| | - Shoji A Baba
- Department of Advanced Biosciences, Graduate School of Humanities and Sciences, Ochanomizu University, Bunkyo, Tokyo 112-8610, Japan
| | - Manabu Yoshida
- Misaki Marine Biological Station, Graduate School of Science, University of Tokyo, Miura, Kanagawa 238-0225, Japan
| | - Shinji Kamimura
- Department of Biological Sciences, Faculty of Science and Engineering, Chuo University, Tokyo 112-8551, Japan
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23
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Seifert R, Flick M, Bönigk W, Alvarez L, Trötschel C, Poetsch A, Müller A, Goodwin N, Pelzer P, Kashikar ND, Kremmer E, Jikeli J, Timmermann B, Kuhl H, Fridman D, Windler F, Kaupp UB, Strünker T. The CatSper channel controls chemosensation in sea urchin sperm. EMBO J 2014; 34:379-92. [PMID: 25535245 DOI: 10.15252/embj.201489376] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Sperm guidance is controlled by chemical and physical cues. In many species, Ca(2+) bursts in the flagellum govern navigation to the egg. In Arbacia punctulata, a model system of sperm chemotaxis, a cGMP signaling pathway controls these Ca(2+) bursts. The underlying Ca(2+) channel and its mechanisms of activation are unknown. Here, we identify CatSper Ca(2+) channels in the flagellum of A. punctulata sperm. We show that CatSper mediates the chemoattractant-evoked Ca(2+) influx and controls chemotactic steering; a concomitant alkalization serves as a highly cooperative mechanism that enables CatSper to transduce periodic voltage changes into Ca(2+) bursts. Our results reveal intriguing phylogenetic commonalities but also variations between marine invertebrates and mammals regarding the function and control of CatSper. The variations probably reflect functional and mechanistic adaptations that evolved during the transition from external to internal fertilization.
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Affiliation(s)
- Reinhard Seifert
- Center of Advanced European Studies and Research (Caesar), Abteilung Molekulare Neurosensorik, Bonn, Germany Marine Biological Laboratory, Woods Hole, MA, USA
| | - Melanie Flick
- Center of Advanced European Studies and Research (Caesar), Abteilung Molekulare Neurosensorik, Bonn, Germany
| | - Wolfgang Bönigk
- Center of Advanced European Studies and Research (Caesar), Abteilung Molekulare Neurosensorik, Bonn, Germany
| | - Luis Alvarez
- Center of Advanced European Studies and Research (Caesar), Abteilung Molekulare Neurosensorik, Bonn, Germany
| | | | - Ansgar Poetsch
- Ruhr-Universität Bochum Lehrstuhl Biochemie der Pflanzen, Bochum, Germany
| | - Astrid Müller
- Center of Advanced European Studies and Research (Caesar), Abteilung Molekulare Neurosensorik, Bonn, Germany
| | - Normann Goodwin
- Marine Biological Laboratory, Woods Hole, MA, USA Laboratory of Molecular Signalling, Babraham Institute, Cambridge, UK
| | - Patric Pelzer
- Marine Biological Laboratory, Woods Hole, MA, USA Institut für Anatomie und Zellbiologie, Abteilung für Funktionelle Neuroanatomie, Universität Heidelberg, Heidelberg, Germany
| | - Nachiket D Kashikar
- Marine Biological Laboratory, Woods Hole, MA, USA Sussex Neuroscience, School of Life Sciences, University of Sussex, Falmer, Brighton, UK
| | - Elisabeth Kremmer
- Helmholtz-Zentrum München, Institut für Molekulare Immunologie, München, Germany
| | - Jan Jikeli
- Center of Advanced European Studies and Research (Caesar), Abteilung Molekulare Neurosensorik, Bonn, Germany
| | | | - Heiner Kuhl
- Max-Planck-Institut für Molekulare Genetik, Berlin, Germany
| | - Dmitry Fridman
- Center of Advanced European Studies and Research (Caesar), Abteilung Molekulare Neurosensorik, Bonn, Germany Marine Biological Laboratory, Woods Hole, MA, USA
| | - Florian Windler
- Center of Advanced European Studies and Research (Caesar), Abteilung Molekulare Neurosensorik, Bonn, Germany Marine Biological Laboratory, Woods Hole, MA, USA
| | - U Benjamin Kaupp
- Center of Advanced European Studies and Research (Caesar), Abteilung Molekulare Neurosensorik, Bonn, Germany Marine Biological Laboratory, Woods Hole, MA, USA
| | - Timo Strünker
- Center of Advanced European Studies and Research (Caesar), Abteilung Molekulare Neurosensorik, Bonn, Germany Marine Biological Laboratory, Woods Hole, MA, USA
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24
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Rectified directional sensing in long-range cell migration. Nat Commun 2014; 5:5367. [PMID: 25373620 PMCID: PMC4272253 DOI: 10.1038/ncomms6367] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 09/25/2014] [Indexed: 12/20/2022] Open
Abstract
How spatial and temporal information are integrated to determine the direction of cell migration remains poorly understood. Here, by precise microfluidics emulation of dynamic chemoattractant waves, we demonstrate that, in Dictyostelium, directional movement as well as activation of small guanosine triphosphatase Ras at the leading edge is suppressed when the chemoattractant concentration is decreasing over time. This 'rectification' of directional sensing occurs only at an intermediate range of wave speed and does not require phosphoinositide-3-kinase or F-actin. From modelling analysis, we show that rectification arises naturally in a single-layered incoherent feedforward circuit with zero-order ultrasensitivity. The required stimulus time-window predicts ~5 s transient for directional sensing response close to Ras activation and inhibitor diffusion typical for protein in the cytosol. We suggest that the ability of Dictyostelium cells to move only in the wavefront is closely associated with rectification of adaptive response combined with local activation and global inhibition.
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In silico determination of the effect of multi-target drugs on calcium dynamics signaling network underlying sea urchin spermatozoa motility. PLoS One 2014; 9:e104451. [PMID: 25162222 PMCID: PMC4146467 DOI: 10.1371/journal.pone.0104451] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2014] [Accepted: 07/08/2014] [Indexed: 11/19/2022] Open
Abstract
The motility of spermatozoa of both Lytechinus pictus and Strongylocentrotus purpuratus sea urchin species is modulated by the egg-derived decapeptide speract via an oscillatory [Ca2+]-dependent signaling pathway. Comprehension of this pathway is hence directly related to the understanding of regulated sperm swimming. Niflumic acid (NFA), a nonsteroidal anti-inflammatory drug alters several ion channels. Though unspecific, NFA profoundly affects how sea urchin sperm respond to speract, increasing the [Ca2+]i oscillation period, amplitude, peak and average level values of the responses in immobilized and swimming cells. A previous logical network model we developed for the [Ca2+] dynamics of speract signaling cascade in sea urchin sperm allows integrated dissection of individual and multiple actions of NFA. Among the channels affected by NFA are: hyperpolarization-activated and cyclic nucleotide gated Na+ channels (HCN), [Ca2+]-dependent Cl- channels (CaCC) and [Ca2+]-dependent K+ channels (CaKC), all present in the sea urchin genome. Here, using our model we investigated the effect of blocking in silico HCN and CaCC channels suggested by experiments. Regarding CaKC channels, arguments can be provided for either their blockage or activation by NFA. Our study yielded two scenarios compliant with experimental observations: i) under CaKC inhibition, this [Ca2+]-dependent K+ channel should be different from the Slo1 channel and ii) under activation of the CaKC channel, another [Ca2+] channel not considered previously in the network is required, such as the pH-dependent CatSper channel. Additionally, our findings predict cause-effect relations resulting from a selective inhibition of those channels. Knowledge of these relations may be of consequence for a variety of electrophysiological studies and have an impact on drug related investigations. Our study contributes to a better grasp of the network dynamics and suggests further experimental work.
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26
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Pichlo M, Bungert-Plümke S, Weyand I, Seifert R, Bönigk W, Strünker T, Kashikar ND, Goodwin N, Müller A, Pelzer P, Van Q, Enderlein J, Klemm C, Krause E, Trötschel C, Poetsch A, Kremmer E, Kaupp UB, Körschen HG, Collienne U. High density and ligand affinity confer ultrasensitive signal detection by a guanylyl cyclase chemoreceptor. J Cell Biol 2014; 206:541-57. [PMID: 25135936 PMCID: PMC4137060 DOI: 10.1083/jcb.201402027] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 07/15/2014] [Indexed: 12/28/2022] Open
Abstract
Guanylyl cyclases (GCs), which synthesize the messenger cyclic guanosine 3',5'-monophosphate, control several sensory functions, such as phototransduction, chemosensation, and thermosensation, in many species from worms to mammals. The GC chemoreceptor in sea urchin sperm can decode chemoattractant concentrations with single-molecule sensitivity. The molecular and cellular underpinnings of such ultrasensitivity are not known for any eukaryotic chemoreceptor. In this paper, we show that an exquisitely high density of 3 × 10(5) GC chemoreceptors and subnanomolar ligand affinity provide a high ligand-capture efficacy and render sperm perfect absorbers. The GC activity is terminated within 150 ms by dephosphorylation steps of the receptor, which provides a means for precise control of the GC lifetime and which reduces "molecule noise." Compared with other ultrasensitive sensory systems, the 10-fold signal amplification by the GC receptor is surprisingly low. The hallmarks of this signaling mechanism provide a blueprint for chemical sensing in small compartments, such as olfactory cilia, insect antennae, or even synaptic boutons.
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Affiliation(s)
- Magdalena Pichlo
- Center of Advanced European Studies and Research, 53175 Bonn, Germany Marine Biological Laboratory, Woods Hole, MA 02543
| | - Stefanie Bungert-Plümke
- Marine Biological Laboratory, Woods Hole, MA 02543 Institute of Complex Systems (ICS-4), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Ingo Weyand
- Marine Biological Laboratory, Woods Hole, MA 02543 Institute of Complex Systems (ICS-4), Forschungszentrum Jülich, 52425 Jülich, Germany
| | - Reinhard Seifert
- Center of Advanced European Studies and Research, 53175 Bonn, Germany Marine Biological Laboratory, Woods Hole, MA 02543
| | - Wolfgang Bönigk
- Center of Advanced European Studies and Research, 53175 Bonn, Germany
| | - Timo Strünker
- Center of Advanced European Studies and Research, 53175 Bonn, Germany Marine Biological Laboratory, Woods Hole, MA 02543
| | - Nachiket Dilip Kashikar
- Center of Advanced European Studies and Research, 53175 Bonn, Germany Marine Biological Laboratory, Woods Hole, MA 02543 Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, England, UK
| | - Normann Goodwin
- Center of Advanced European Studies and Research, 53175 Bonn, Germany Marine Biological Laboratory, Woods Hole, MA 02543 Babraham Institute, Cambridge CB22 3AT, England, UK
| | - Astrid Müller
- Center of Advanced European Studies and Research, 53175 Bonn, Germany
| | - Patric Pelzer
- Marine Biological Laboratory, Woods Hole, MA 02543 Department of Functional Neuroanatomy, Institute of Anatomy and Cell Biology, Heidelberg University, 69120 Heidelberg, Germany
| | - Qui Van
- III. Physikalisches Institut, Universität Göttingen, 37077 Göttingen, Germany
| | - Jörg Enderlein
- III. Physikalisches Institut, Universität Göttingen, 37077 Göttingen, Germany
| | - Clementine Klemm
- Leibniz-Institut für Molekulare Pharmakologie, 13125 Berlin, Germany
| | - Eberhard Krause
- Leibniz-Institut für Molekulare Pharmakologie, 13125 Berlin, Germany
| | | | - Ansgar Poetsch
- Plant Biochemistry, Ruhr University Bochum. 44801 Bochum, Germany
| | - Elisabeth Kremmer
- Institut für Molekulare Immunologie, Helmholtz-Zentrum München, 81377 München, Germany
| | - U Benjamin Kaupp
- Center of Advanced European Studies and Research, 53175 Bonn, Germany Marine Biological Laboratory, Woods Hole, MA 02543
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27
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Nishigaki T, José O, González-Cota AL, Romero F, Treviño CL, Darszon A. Intracellular pH in sperm physiology. Biochem Biophys Res Commun 2014; 450:1149-58. [PMID: 24887564 PMCID: PMC4146485 DOI: 10.1016/j.bbrc.2014.05.100] [Citation(s) in RCA: 122] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Accepted: 05/22/2014] [Indexed: 10/25/2022]
Abstract
Intracellular pH (pHi) regulation is essential for cell function. Notably, several unique sperm ion transporters and enzymes whose elimination causes infertility are either pHi dependent or somehow related to pHi regulation. Amongst them are: CatSper, a Ca(2+) channel; Slo3, a K(+) channel; the sperm-specific Na(+)/H(+) exchanger and the soluble adenylyl cyclase. It is thus clear that pHi regulation is of the utmost importance for sperm physiology. This review briefly summarizes the key components involved in pHi regulation, their characteristics and participation in fundamental sperm functions such as motility, maturation and the acrosome reaction.
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Affiliation(s)
- Takuya Nishigaki
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico
| | - Omar José
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico
| | - Ana Laura González-Cota
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico
| | - Francisco Romero
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico
| | - Claudia L Treviño
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico
| | - Alberto Darszon
- Departamento de Genética del Desarrollo y Fisiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, 62210, Mexico.
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28
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Alvarez L, Friedrich BM, Gompper G, Kaupp UB. The computational sperm cell. Trends Cell Biol 2013; 24:198-207. [PMID: 24342435 DOI: 10.1016/j.tcb.2013.10.004] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2013] [Revised: 10/13/2013] [Accepted: 10/14/2013] [Indexed: 10/25/2022]
Abstract
Sperm are guided to the egg by a gradient of chemical attractants - a process called chemotaxis. The binding of the chemoattractant to receptors on the surface of the flagellum triggers a cascade of signaling events that eventually lead to an influx of Ca(2+) ions. Based on these Ca(2+) surges, which control the waveform of the flagellar beat, sperm adjust their swimming path toward the egg. In past years, many components of chemotactic signaling have been identified. Moreover, kinetic spectroscopy and imaging techniques unraveled the sequence of cellular events controlling swimming behavior. During navigation in a chemical gradient, sperm perform a surprising variety of computational operations. Here we discuss theoretical concepts of navigation strategies and the cellular underpinnings.
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Affiliation(s)
- Luis Alvarez
- Center of Advanced European Studies and Research (CAESAR), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany.
| | - Benjamin M Friedrich
- Max Planck Institute for the Physics of Complex Systems, Nöthnitzer Straße 38, 01187 Dresden, Germany
| | - Gerhard Gompper
- Research Centre Jülich, Institute of Complex Systems (ICS-2), 52425 Jülich, Germany
| | - U Benjamin Kaupp
- Center of Advanced European Studies and Research (CAESAR), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany.
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29
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Yeates SE, Diamond SE, Einum S, Emerson BC, Holt WV, Gage MJG. Cryptic choice of conspecific sperm controlled by the impact of ovarian fluid on sperm swimming behavior. Evolution 2013; 67:3523-36. [PMID: 24299405 PMCID: PMC3912916 DOI: 10.1111/evo.12208] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Accepted: 06/29/2013] [Indexed: 12/19/2022]
Abstract
Despite evidence that variation in male-female reproductive compatibility exists in many fertilization systems, identifying mechanisms of cryptic female choice at the gamete level has been a challenge. Here, under risks of genetic incompatibility through hybridization, we show how salmon and trout eggs promote fertilization by conspecific sperm. Using in vitro fertilization experiments that replicate the gametic microenvironment, we find complete interfertility between both species. However, if either species' ova were presented with equivalent numbers of both sperm types, conspecific sperm gained fertilization precedence. Surprisingly, the species' identity of the eggs did not explain this cryptic female choice, which instead was primarily controlled by conspecific ovarian fluid, a semiviscous, protein-rich solution that bathes the eggs and is released at spawning. Video analyses revealed that ovarian fluid doubled sperm motile life span and straightened swimming trajectory, behaviors allowing chemoattraction up a concentration gradient. To confirm chemoattraction, cell migration tests through membranes containing pores that approximated to the egg micropyle showed that conspecific ovarian fluid attracted many more spermatozoa through the membrane, compared with heterospecific fluid or water. These combined findings together identify how cryptic female choice can evolve at the gamete level and promote reproductive isolation, mediated by a specific chemoattractive influence of ovarian fluid on sperm swimming behavior.
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Affiliation(s)
- Sarah E Yeates
- School of Biological Sciences, University of East AngliaNorwich Research Park, Norwich, NR4 7TJ, United Kingdom
| | - Sian E Diamond
- School of Biological Sciences, University of East AngliaNorwich Research Park, Norwich, NR4 7TJ, United Kingdom
| | - Sigurd Einum
- Centre for Biodiversity Dynamics, Department of Biology, Norwegian University of Science and Technology, NO-7491Trondheim, Norway
- Norwegian Institute for Nature Research, NO-7485Trondheim, Norway
| | - Brent C Emerson
- School of Biological Sciences, University of East AngliaNorwich Research Park, Norwich, NR4 7TJ, United Kingdom
- Island Ecology and Evolution Research Group (IPNA-CSIC), C/Astrofísico Francisco Sánchez 338206 La Laguna, Tenerife, Canary Islands, Spain
| | - William V Holt
- Academic Department of Reproductive and Developmental Medicine, University of SheffieldLevel 4, Jessop Wing, Tree Root Walk, Sheffield, S10 2SF, United Kingdom
| | - Matthew J G Gage
- School of Biological Sciences, University of East AngliaNorwich Research Park, Norwich, NR4 7TJ, United Kingdom
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30
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Affiliation(s)
- U B Kaupp
- Department of Molecular Sensory Systems, Center of Advanced European Studies and Research, 53175 Bonn, Germany
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31
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Evans JP, Sherman CDH. Sexual selection and the evolution of egg-sperm interactions in broadcast-spawning invertebrates. THE BIOLOGICAL BULLETIN 2013; 224:166-183. [PMID: 23995741 DOI: 10.1086/bblv224n3p166] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Many marine invertebrate taxa are broadcast spawners, where multiple individuals release their gametes into the water for external fertilization, often in the presence of gametes from heterospecifics. Consequently, sperm encounter the considerable challenges of locating and fertilizing eggs from conspecific females. To overcome these challenges, many taxa exhibit species-specific attraction of sperm toward eggs through chemical signals released from eggs (sperm chemotaxis) and species-specific gamete recognition proteins (GRPs) that mediate compatibility of gametes at fertilization. In this prospective review, we highlight these selective forces, but also emphasize the role that sexual selection, manifested through sperm competition, cryptic female choice, and evolutionary conflicts of interest between the sexes (sexual conflict), can also play in mediating the action of egg chemoattractants and GRPs, and thus individual reproductive fitness. Furthermore, we explore patterns of selection at the level of gametes (sperm phenotype, gamete plasticity, and egg traits) to identify putative traits targeted by sexual selection in these species. We conclude by emphasizing the excellent, but relatively untapped, potential of broadcast-spawning marine invertebrates as model systems to illuminate several areas of research in post-mating sexual selection.
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Affiliation(s)
- Jonathan P Evans
- Centre for Evolutionary Biology, School of Animal Biology, University of Western Australia, Crawley, Australia.
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32
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Guerrero A, Espinal J, Wood CD, Rendón JM, Carneiro J, Martínez-Mekler G, Darszon A. Niflumic acid disrupts marine spermatozoan chemotaxis without impairing the spatiotemporal detection of chemoattractant gradients. J Cell Sci 2013; 126:1477-87. [DOI: 10.1242/jcs.121442] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
In many broadcast-spawning marine organisms, oocytes release chemicals that guide conspecific spermatozoa towards their source through chemotaxis. In the sea urchin Lytechinus pictus, the chemoattractant peptide speract triggers a train of fluctuations of intracellular Ca2+ concentration in the sperm flagella. Each transient Ca2+ elevation leads to a momentary increase in flagellar bending asymmetry, known as a chemotactic turn. Furthermore, chemotaxis requires a precise spatiotemporal coordination between the Ca2+-dependent turns and the form of chemoattractant gradient. Spermatozoa that display Ca2+-dependent turns while swimming down the chemoattractant gradient, and conversely suppress turning events while swimming up gradient, successfully approach the center of the gradient. Previous experiments in Strongylocentrotus purpuratus sea urchin spermatozoa showed that niflumic acid (NFA), an inhibitor of several ion channels, drastically altered the speract-induced Ca2+ fluctuations and swimming patterns. In this study, mathematical modeling of the speract-dependent Ca2+ signaling pathway suggests that NFA, by potentially affecting HCN, CaCC and CaKC channels, may alter the temporal organization of Ca2+ fluctuations, and therefore disrupt chemotaxis. Here we investigate our hypothesis using a novel automated method for analyzing sperm behavior. We show that NFA does indeed disrupt chemotactic responses of L. pictus spermatozoa, although the temporal coordination between the Ca2+-dependent turns and the form of chemoattractant gradient is unaltered. Instead, NFA disrupts sperm chemotaxis by altering the arc length traveled during each chemotactic turning event. This alteration in the chemotactic turn trajectory disorientates spermatozoa at the termination of the turning event. We conclude that NFA disrupts chemotaxis without affecting how the spermatozoa decode environmental cues.
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33
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Abstract
Study shows how a sperm's behavior shapes its swimming path.
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