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Rieu JP, Cochet-Escartin O, Anjard C, Demircigil M, Calvez V. Commentary: The Dynamics of Aerotaxis in a Simple Eukaryotic Model. Front Cell Dev Biol 2022; 10:844812. [PMID: 35309919 PMCID: PMC8924511 DOI: 10.3389/fcell.2022.844812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 01/20/2022] [Indexed: 11/13/2022] Open
Affiliation(s)
- Jean-Paul Rieu
- Institut Lumière Matière, UMR5306, Université Lyon 1-CNRS, Université de Lyon, Villeurbanne, France
| | - Olivier Cochet-Escartin
- Institut Lumière Matière, UMR5306, Université Lyon 1-CNRS, Université de Lyon, Villeurbanne, France
| | - Christophe Anjard
- Institut Lumière Matière, UMR5306, Université Lyon 1-CNRS, Université de Lyon, Villeurbanne, France
| | - Mete Demircigil
- Institut Camille Jordan, UMR5208, Université Lyon 1-CNRS, Université de Lyon, Villeurbanne, France
| | - Vincent Calvez
- Institut Camille Jordan, UMR5208, Université Lyon 1-CNRS, Université de Lyon, Villeurbanne, France
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Hirose S, Rieu JP, Anjard C, Cochet-Escartin O, Kikuchi H, Funamoto K. Aerotaxis and aerokinesis of Dictyostelium discoideum under hypoxic microenvironments. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2021; 2021:1187-1190. [PMID: 34891499 DOI: 10.1109/embc46164.2021.9629752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Although spatiotemporal changes of oxygen in a microenvironment are known to affect the cellular dynamics of various eukaryotes, the details are not fully understood. Here, we describe the aerotaxis and aerokinesis of Dictyostelium discoideum (Dd), which has long been employed as a model organism for eukaryotic cells. We developed a microfluidic device capable of time-lapse observation of cultured cells while controlling oxygen concentrations in microchannels. Migratory behaviors of Dd were observed and quantitatively evaluated under an oxygen concentration gradient from 0% to 21% O2, as well as in various uniform oxygen conditions. In a hypoxic region within the oxygen concentration gradient, Dd migrated toward regions of higher oxygen concentration at increased velocity, which was independent of cell density. Observed under uniform oxygen concentrations of 1%, 2%, 3%, and 21%, the migration velocity of Dd increased significantly in hypoxic environments of 2% O2 or less. Thus, Dd shows aerotaxis, directed by the oxygen concentration gradient, and simultaneously shows aerokinesis, changing the migration velocity according to the oxygen concentration itself.
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Cochet-Escartin O, Demircigil M, Hirose S, Allais B, Gonzalo P, Mikaelian I, Funamoto K, Anjard C, Calvez V, Rieu JP. Hypoxia triggers collective aerotactic migration in Dictyostelium discoideum. eLife 2021; 10:64731. [PMID: 34415238 PMCID: PMC8378850 DOI: 10.7554/elife.64731] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 07/30/2021] [Indexed: 01/26/2023] Open
Abstract
Using a self-generated hypoxic assay, we show that the amoeba Dictyostelium discoideum displays a remarkable collective aerotactic behavior. When a cell colony is covered, cells quickly consume the available oxygen (O2) and form a dense ring moving outwards at constant speed and density. To decipher this collective process, we combined two technological developments: porphyrin-based O2 -sensing films and microfluidic O2 gradient generators. We showed that Dictyostelium cells exhibit aerotactic and aerokinetic response in a low range of O2 concentration indicative of a very efficient detection mechanism. Cell behaviors under self-generated or imposed O2 gradients were modeled using an in silico cellular Potts model built on experimental observations. This computational model was complemented with a parsimonious ‘Go or Grow’ partial differential equation (PDE) model. In both models, we found that the collective migration of a dense ring can be explained by the interplay between cell division and the modulation of aerotaxis.
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Affiliation(s)
- Olivier Cochet-Escartin
- Institut Lumière Matière, UMR5306, Université Lyon 1-CNRS, Université de Lyon, Villeurbanne, France
| | - Mete Demircigil
- Institut Camille Jordan, UMR5208, Université Lyon 1-CNRS, Université de Lyon, Villeurbanne, France
| | - Satomi Hirose
- Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan.,Institute of Fluid Science, Tohoku University, Sendai, Japan
| | - Blandine Allais
- Institut Lumière Matière, UMR5306, Université Lyon 1-CNRS, Université de Lyon, Villeurbanne, France
| | - Philippe Gonzalo
- Centre Léon Bérard, Centre de recherche en cancérologie de Lyon, INSERM 1052, CNRS 5286, Université Lyon 1, Université de Lyon, Lyon, France.,Laboratoire de Biochimie et Pharmacologie, Faculté de médecine de Saint-Etienne, CHU de Saint-Etienne, Saint-Etienne, France
| | - Ivan Mikaelian
- Centre Léon Bérard, Centre de recherche en cancérologie de Lyon, INSERM 1052, CNRS 5286, Université Lyon 1, Université de Lyon, Lyon, France
| | - Kenichi Funamoto
- Graduate School of Biomedical Engineering, Tohoku University, Sendai, Japan.,Institute of Fluid Science, Tohoku University, Sendai, Japan.,Graduate School of Engineering, Tohoku University, Sendai, Japan
| | - Christophe Anjard
- Institut Lumière Matière, UMR5306, Université Lyon 1-CNRS, Université de Lyon, Villeurbanne, France
| | - Vincent Calvez
- Institut Camille Jordan, UMR5208, Université Lyon 1-CNRS, Université de Lyon, Villeurbanne, France
| | - Jean-Paul Rieu
- Institut Lumière Matière, UMR5306, Université Lyon 1-CNRS, Université de Lyon, Villeurbanne, France
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Kuznetsov AV, Kuleshova ON, Pronozin AY, Krivenko OV, Zavyalova OS. Effects of low frequency rectangular electric pulses on Trichoplax (Placozoa). ACTA ACUST UNITED AC 2020. [DOI: 10.21072/mbj.2020.05.2.05] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The effect of extremely low frequency electric and magnetic fields (ELF-EMF) on plants and animals including humans is quite a contentious issue. Little is known about ELF-EMF effect on hydrobionts, too. We studied the effect of square voltage waves of various amplitude, duration, and duty cycle, passed through seawater, on Trichoplax organisms as a possible test laboratory model. Three Placozoa strains, such as Trichoplax adhaerens (H1), Trichoplax sp. (H2), and Hoilungia hongkongensis (H13), were used in experiments. They were picked at the stationary growth phase. Arduino Uno electronics platform was used to generate a sequence of rectangular pulses of given duration and duty cycle with a frequency up to 2 kHz. Average voltage up to 500 mV was regulated by voltage divider circuit. Amlodipine, an inhibitor of calcium channel activity, was used to check the specificity of electrical pulse effect on voltage-gated calcium channels in Trichoplax. Experimental animals were investigated under a stereo microscope and stimulated by current-carrying electrodes placed close to a Trichoplax body. Variations in behavior and morphological characteristics of Trichoplax plate were studied. Stimulating and suppressing effects were identified. Experimental observations were recorded using photo and video techniques. Motion trajectories of individual animals were tracked. Increasing voltage pulses with fixed frequency of 20 Hz caused H2 haplotype individuals to leave “electrode zone” within several minutes at a voltage of 25 mV. They lost mobility in proportion to voltage rise and were paralyzed at a voltage of 500 mV. Therefore, a voltage of 50 mV was used in further experiments. An animal had more chance to move in various directions in experiments with two electrodes located on one side instead of both sides of Trichoplax. Direction of motion was used as a characteristic feature. Trichoplax were observed to migrate to areas with low density of electric field lines, which are far from electrodes or behind them. Animals from old culture were less sensitive to electrical stimulus. H2 strain was more reactive than H1 strain and especially than H13 strain; it demonstrated stronger physiological responses at frequencies of 2 Hz and 2 kHz with a voltage of 50 mV. Motion patterns and animal morphology depended on the duration of rectangular stimulation pulses, their number, amplitude, and frequency. Effects observed varied over a wide range: from direct or stochastic migration of animals to the anode or the cathode or away from it to their immobility, an increase of optical density around and in the middle of Trichoplax plate, and finally to Trichoplax folding and detach from the substrate. Additional experiments on Trichoplax sp. H2 with pulse duration of 35 ms and pulse delay of 1 ms to 10 s showed that the fraction of paralyzed animals increased up to 80 % with minimum delay. Nevertheless, in the presence of amlodipine with a concentration of 25 nM, almost all Trichoplax remained fast-moving for several minutes despite exposure to voltage waves. Experimental animals showed a total discoordination of motion and could not leave an “electrode trap”, when amlodipine with a concentration of 250 nM was used. Further, Trichoplax plate became rigid, which appeared in animal shape invariability during motion. Finally, amlodipine with a concentration of 50 μM caused a rapid folding of animal plate-like body into a pan in the ventral-dorsal direction and subsequent dissociation of Trichoplax plate into individual cells. In general, the electrical exposure applied demonstrated a cumulative but a reversible physiological effect, which, as expected, is associated with activity of voltage-gated calcium channels. Amlodipine at high concentration (50 μM) caused Trichoplax disintegration; at moderate concentration (250 nM), it disrupted the propagation of activation waves that led to discoordination of animal motion; at low concentration (25 nM), it prevented an electric shock.
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Bubba F, Lorenzi T, Macfarlane FR. From a discrete model of chemotaxis with volume-filling to a generalized Patlak-Keller-Segel model. Proc Math Phys Eng Sci 2020; 476:20190871. [PMID: 32523414 DOI: 10.1098/rspa.2019.0871] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Accepted: 04/02/2020] [Indexed: 12/26/2022] Open
Abstract
We present a discrete model of chemotaxis whereby cells responding to a chemoattractant are seen as individual agents whose movement is described through a set of rules that result in a biased random walk. In order to take into account possible alterations in cellular motility observed at high cell densities (i.e. volume-filling), we let the probabilities of cell movement be modulated by a decaying function of the cell density. We formally show that a general form of the celebrated Patlak-Keller-Segel (PKS) model of chemotaxis can be formally derived as the appropriate continuum limit of this discrete model. The family of steady-state solutions of such a generalized PKS model are characterized and the conditions for the emergence of spatial patterns are studied via linear stability analysis. Moreover, we carry out a systematic quantitative comparison between numerical simulations of the discrete model and numerical solutions of the corresponding PKS model, both in one and in two spatial dimensions. The results obtained indicate that there is excellent quantitative agreement between the spatial patterns produced by the two models. Finally, we numerically show that the outcomes of the two models faithfully replicate those of the classical PKS model in a suitable asymptotic regime.
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Affiliation(s)
- Federica Bubba
- Sorbonne Universités, Universités Paris-Diderot, Laboratoire Jacques-Louis Lions, 75005 Paris, France
| | - Tommaso Lorenzi
- School of Mathematics and Statistics, University of St Andrews, St Andrews KY16 9SS, UK.,Department of Mathematical Sciences 'G. L. Lagrange', Dipartimento di Eccellenza 2018-2022, Politecnico di Torino, 10129 Torino, Italy
| | - Fiona R Macfarlane
- School of Mathematics and Statistics, University of St Andrews, St Andrews KY16 9SS, UK
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Abstract
Loners—individuals out of sync with a coordinated majority—occur frequently in nature. Are loners incidental byproducts of large-scale coordination attempts, or are they part of a mosaic of life-history strategies? Here, we provide empirical evidence of naturally occurring heritable variation in loner behavior in the model social amoeba Dictyostelium discoideum. We propose that Dictyostelium loners—cells that do not join the multicellular life stage—arise from a dynamic population-partitioning process, the result of each cell making a stochastic, signal-based decision. We find evidence that this imperfectly synchronized multicellular development is affected by both abiotic (environmental porosity) and biotic (signaling) factors. Finally, we predict theoretically that when a pair of strains differing in their partitioning behavior coaggregate, cross-signaling impacts slime-mold diversity across spatiotemporal scales. Our findings suggest that loners could be critical to understanding collective and social behaviors, multicellular development, and ecological dynamics in D. discoideum. More broadly, across taxa, imperfect coordination of collective behaviors might be adaptive by enabling diversification of life-history strategies. Loners (individuals out of sync with a coordinated majority) occur frequently in nature and are generally assumed to be incidental by-products of imperfect coordination attempts. Experimental and theoretical work on the slime mold Dictyostelium discoideum suggests that "lonerism" might actually be an alternative life-history strategy.
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