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Larbi MC, Messa G, Jalal H, Koutsikou S. An early midbrain sensorimotor pathway is involved in the timely initiation and direction of swimming in the hatchling Xenopus laevis tadpole. Front Neural Circuits 2022; 16:1027831. [PMID: 36619662 PMCID: PMC9810627 DOI: 10.3389/fncir.2022.1027831] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 11/25/2022] [Indexed: 12/24/2022] Open
Abstract
Vertebrate locomotion is heavily dependent on descending control originating in the midbrain and subsequently influencing central pattern generators in the spinal cord. However, the midbrain neuronal circuitry and its connections with other brainstem and spinal motor circuits has not been fully elucidated. Vertebrates with very simple nervous system, like the hatchling Xenopus laevis tadpole, have been instrumental in unravelling fundamental principles of locomotion and its suspraspinal control. Here, we use behavioral and electrophysiological approaches in combination with lesions of the midbrain to investigate its contribution to the initiation and control of the tadpole swimming in response to trunk skin stimulation. None of the midbrain lesions studied here blocked the tadpole's sustained swim behavior following trunk skin stimulation. However, we identified that distinct midbrain lesions led to significant changes in the latency and trajectory of swimming. These changes could partly be explained by the increase in synchronous muscle contractions on the opposite sides of the tadpole's body and permanent deflection of the tail from its normal position, respectively. We conclude that the tadpole's embryonic trunk skin sensorimotor pathway involves the midbrain, which harbors essential neuronal circuitry to significantly contribute to the appropriate, timely and coordinated selection and execution of locomotion, imperative to the animal's survival.
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Gao L, Meiring JCM, Varady A, Ruider IE, Heise C, Wranik M, Velasco CD, Taylor JA, Terni B, Weinert T, Standfuss J, Cabernard CC, Llobet A, Steinmetz MO, Bausch AR, Distel M, Thorn-Seshold J, Akhmanova A, Thorn-Seshold O. In Vivo Photocontrol of Microtubule Dynamics and Integrity, Migration and Mitosis, by the Potent GFP-Imaging-Compatible Photoswitchable Reagents SBTubA4P and SBTub2M. J Am Chem Soc 2022; 144:5614-5628. [PMID: 35290733 PMCID: PMC8972266 DOI: 10.1021/jacs.2c01020] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Photoswitchable reagents are powerful tools for high-precision studies in cell biology. When these reagents are globally administered yet locally photoactivated in two-dimensional (2D) cell cultures, they can exert micron- and millisecond-scale biological control. This gives them great potential for use in biologically more relevant three-dimensional (3D) models and in vivo, particularly for studying systems with inherent spatiotemporal complexity, such as the cytoskeleton. However, due to a combination of photoswitch isomerization under typical imaging conditions, metabolic liabilities, and insufficient water solubility at effective concentrations, the in vivo potential of photoswitchable reagents addressing cytosolic protein targets remains largely unrealized. Here, we optimized the potency and solubility of metabolically stable, druglike colchicinoid microtubule inhibitors based on the styrylbenzothiazole (SBT) scaffold that are nonresponsive to typical fluorescent protein imaging wavelengths and so enable multichannel imaging studies. We applied these reagents both to 3D organoids and tissue explants and to classic model organisms (zebrafish, clawed frog) in one- and two-protein imaging experiments, in which spatiotemporally localized illuminations allowed them to photocontrol microtubule dynamics, network architecture, and microtubule-dependent processes in vivo with cellular precision and second-level resolution. These nanomolar, in vivo capable photoswitchable reagents should open up new dimensions for high-precision cytoskeleton research in cargo transport, cell motility, cell division, and development. More broadly, their design can also inspire similarly capable optical reagents for a range of cytosolic protein targets, thus bringing in vivo photopharmacology one step closer to general realization.
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Affiliation(s)
- Li Gao
- Department of Pharmacy, Ludwig-Maximilians University of Munich, Munich 81377, Germany
| | - Joyce C M Meiring
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht CH 3584, Netherlands
| | - Adam Varady
- St. Anna Children's Cancer Research Institute (CCRI), Vienna 1090, Austria
| | - Iris E Ruider
- Physics Department and Center for Protein Assemblies CPA, Technical University of Munich, Garching 85747, Germany
| | - Constanze Heise
- Department of Pharmacy, Ludwig-Maximilians University of Munich, Munich 81377, Germany
| | - Maximilian Wranik
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institut, Villigen 5232, Switzerland
| | - Cecilia D Velasco
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapy, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Barcelona 08907, Spain.,Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, Barcelona 08907, Spain
| | - Jennifer A Taylor
- Department of Biology, University of Washington, Seattle, Washington 98195, United States
| | - Beatrice Terni
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapy, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Barcelona 08907, Spain.,Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, Barcelona 08907, Spain
| | - Tobias Weinert
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institut, Villigen 5232, Switzerland
| | - Jörg Standfuss
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institut, Villigen 5232, Switzerland
| | - Clemens C Cabernard
- Department of Biology, University of Washington, Seattle, Washington 98195, United States
| | - Artur Llobet
- Laboratory of Neurobiology, Department of Pathology and Experimental Therapy, Institute of Neurosciences, University of Barcelona, L'Hospitalet de Llobregat, Barcelona 08907, Spain.,Bellvitge Biomedical Research Institute (IDIBELL), L'Hospitalet de Llobregat, Barcelona 08907, Spain
| | - Michel O Steinmetz
- Laboratory of Biomolecular Research, Division of Biology and Chemistry, Paul Scherrer Institut, Villigen 5232, Switzerland.,Biozentrum, University of Basel, Basel 4056, Switzerland
| | - Andreas R Bausch
- Physics Department and Center for Protein Assemblies CPA, Technical University of Munich, Garching 85747, Germany
| | - Martin Distel
- St. Anna Children's Cancer Research Institute (CCRI), Vienna 1090, Austria.,Zebrafish Platform Austria for Preclinical Drug Screening (ZANDR), Vienna 1090, Austria
| | - Julia Thorn-Seshold
- Department of Pharmacy, Ludwig-Maximilians University of Munich, Munich 81377, Germany
| | - Anna Akhmanova
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, Utrecht University, Utrecht CH 3584, Netherlands
| | - Oliver Thorn-Seshold
- Department of Pharmacy, Ludwig-Maximilians University of Munich, Munich 81377, Germany
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Sarkar K, Bonnerjee D, Srivastava R, Bagh S. A single layer artificial neural network type architecture with molecular engineered bacteria for reversible and irreversible computing. Chem Sci 2021; 12:15821-15832. [PMID: 35024106 PMCID: PMC8672730 DOI: 10.1039/d1sc01505b] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 11/08/2021] [Indexed: 11/21/2022] Open
Abstract
Here, we adapted the basic concept of artificial neural networks (ANNs) and experimentally demonstrate a broadly applicable single layer ANN type architecture with molecular engineered bacteria to perform complex irreversible computing like multiplexing, de-multiplexing, encoding, decoding, majority functions, and reversible computing like Feynman and Fredkin gates. The encoder and majority functions and reversible computing were experimentally implemented within living cells for the first time. We created cellular devices, which worked as artificial neuro-synapses in bacteria, where input chemical signals were linearly combined and processed through a non-linear activation function to produce fluorescent protein outputs. To create such cellular devices, we established a set of rules by correlating truth tables, mathematical equations of ANNs, and cellular device design, which unlike cellular computing, does not require a circuit diagram and the equation directly correlates the design of the cellular device. To our knowledge this is the first adaptation of ANN type architecture with engineered cells. This work may have significance in establishing a new platform for cellular computing, reversible computing and in transforming living cells as ANN-enabled hardware.
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Affiliation(s)
- Kathakali Sarkar
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Homi Bhabha National Institute (HBNI) Block A/F, Sector-I, Bidhannagar Kolkata 700064 India
| | - Deepro Bonnerjee
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Homi Bhabha National Institute (HBNI) Block A/F, Sector-I, Bidhannagar Kolkata 700064 India
| | - Rajkamal Srivastava
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Homi Bhabha National Institute (HBNI) Block A/F, Sector-I, Bidhannagar Kolkata 700064 India
| | - Sangram Bagh
- Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Homi Bhabha National Institute (HBNI) Block A/F, Sector-I, Bidhannagar Kolkata 700064 India
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From decision to action: Detailed modelling of frog tadpoles reveals neuronal mechanisms of decision-making and reproduces unpredictable swimming movements in response to sensory signals. PLoS Comput Biol 2021; 17:e1009654. [PMID: 34898604 PMCID: PMC8699619 DOI: 10.1371/journal.pcbi.1009654] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 12/23/2021] [Accepted: 11/17/2021] [Indexed: 01/30/2023] Open
Abstract
How does the brain process sensory stimuli, and decide whether to initiate locomotor behaviour? To investigate this question we develop two whole body computer models of a tadpole. The "Central Nervous System" (CNS) model uses evidence from whole-cell recording to define 2300 neurons in 12 classes to study how sensory signals from the skin initiate and stop swimming. In response to skin stimulation, it generates realistic sensory pathway spiking and shows how hindbrain sensory memory populations on each side can compete to initiate reticulospinal neuron firing and start swimming. The 3-D "Virtual Tadpole" (VT) biomechanical model with realistic muscle innervation, body flexion, body-water interaction, and movement is then used to evaluate if motor nerve outputs from the CNS model can produce swimming-like movements in a volume of "water". We find that the whole tadpole VT model generates reliable and realistic swimming. Combining these two models opens new perspectives for experiments.
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Saccomanno V, Love H, Sylvester A, Li WC. The early development and physiology of Xenopus laevis tadpole lateral line system. J Neurophysiol 2021; 126:1814-1830. [PMID: 34705593 DOI: 10.1152/jn.00618.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Xenopus laevis has a lateral line mechanosensory system throughout its full life cycle, and a previous study on prefeeding stage tadpoles revealed that it may play a role in motor responses to both water suction and water jets. Here, we investigated the physiology of the anterior lateral line system in newly hatched tadpoles and the motor outputs induced by its activation in response to brief suction stimuli. High-speed videoing showed tadpoles tended to turn and swim away when strong suction was applied close to the head. The lateral line neuromasts were revealed by using DASPEI staining, and their inactivation with neomycin eliminated tadpole motor responses to suction. In immobilized preparations, suction or electrically stimulating the anterior lateral line nerve reliably initiated swimming but the motor nerve discharges implicating turning was observed only occasionally. The same stimulation applied during ongoing fictive swimming produced a halting response. The anterior lateral line nerve showed spontaneous afferent discharges at rest and increased activity during stimulation. Efferent activities were only recorded during tadpole fictive swimming and were largely synchronous with the ipsilateral motor nerve discharges. Finally, calcium imaging identified neurons with fluorescence increase time-locked with suction stimulation in the hindbrain and midbrain. A cluster of neurons at the entry point of the anterior lateral line nerve in the dorsolateral hindbrain had the shortest latency in their responses, supporting their potential sensory interneuron identity. Future studies need to reveal how the lateral line sensory information is processed by the central circuit to determine tadpole motor behavior.NEW & NOTEWORTHY We studied Xenopus tadpole motor responses to anterior lateral line stimulation using high-speed videos, electrophysiology and calcium imaging. Activating the lateral line reliably started swimming. At high stimulation intensities, turning was observed behaviorally but suitable motor nerve discharges were seen only occasionally in immobilized tadpoles. Suction applied during swimming produced a halting response. We analyzed afferent and efferent activities of the tadpole anterior lateral line nerve and located sensory interneurons using calcium imaging.
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Affiliation(s)
- Valentina Saccomanno
- School of Psychology and Neuroscience, grid.11914.3cUniversity of St Andrews, Fife, United Kingdom.,Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Heather Love
- School of Psychology and Neuroscience, grid.11914.3cUniversity of St Andrews, Fife, United Kingdom
| | - Amy Sylvester
- School of Psychology and Neuroscience, grid.11914.3cUniversity of St Andrews, Fife, United Kingdom
| | - Wen-Chang Li
- School of Psychology and Neuroscience, grid.11914.3cUniversity of St Andrews, Fife, United Kingdom
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Rospars JP, Meyer-Vernet N. How fast do mobile organisms respond to stimuli? Response times from bacteria to elephants and whales. Phys Biol 2021; 18:026002. [PMID: 33232948 DOI: 10.1088/1478-3975/abcd88] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Quick responses to fast changes in the environment are crucial in animal behaviour and survival, for example to seize prey, escape predators, or negotiate obstacles. Here, we study the 'simple response time' that is the time elapsed between receptor stimulation and motor activation as typically shown in escape responses, for mobile organisms of various taxa ranging from bacteria to large vertebrates. We show that 95% of these simple response times lie within one order of magnitude of the overall geometric mean of about 25 ms, which is similar to that of a well-studied sensory time scale, the inverse of the critical flicker fusion frequency in vision, also lying within close bounds for all the organisms studied. We find that this time scale is a few times smaller than the minimum time to move by one body length, which is known to lie also within a relatively narrow range for all moving organisms. The remarkably small 102-fold range of the simple response time among so disparate life forms varying over 1020-fold in body mass suggests that it is determined by basic physicochemical constraints, independently on the structure and scale of the organism. We thus propose first-principle estimates of the simple response and sensory time scales in terms of physical constants and a few basic biological properties common to mobile organisms and constraining their responses.
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Affiliation(s)
- Jean-Pierre Rospars
- Institute of Ecology and Environmental Sciences of Paris, INRAE, Route de Saint-Cyr, 78000 Versailles, France
| | - Nicole Meyer-Vernet
- LESIA, Observatoire de Paris, Université PSL, CNRS, Sorbonne Université, Université de Paris, 5 place Jules Janssen, 92195 Meudon, France
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