1
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Klimek A, Mondal D, Block S, Sharma P, Netz RR. Data-driven classification of individual cells by their non-Markovian motion. Biophys J 2024; 123:1173-1183. [PMID: 38515300 PMCID: PMC11140416 DOI: 10.1016/j.bpj.2024.03.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2024] [Revised: 03/11/2024] [Accepted: 03/18/2024] [Indexed: 03/23/2024] Open
Abstract
We present a method to differentiate organisms solely by their motion based on the generalized Langevin equation (GLE) and use it to distinguish two different swimming modes of strongly confined unicellular microalgae Chlamydomonas reinhardtii. The GLE is a general model for active or passive motion of organisms and particles that can be derived from a time-dependent general many-body Hamiltonian and in particular includes non-Markovian effects (i.e., the trajectory memory of its past). We extract all GLE parameters from individual cell trajectories and perform an unbiased cluster analysis to group them into different classes. For the specific cell population employed in the experiments, the GLE-based assignment into the two different swimming modes works perfectly, as checked by control experiments. The classification and sorting of single cells and organisms is important in different areas; our method, which is based on motion trajectories, offers wide-ranging applications in biology and medicine.
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Affiliation(s)
- Anton Klimek
- Fachbereich Physik, Freie Universität Berlin, Berlin, Germany
| | - Debasmita Mondal
- Department of Physics, Indian Institute of Science, Bangalore, India; James Franck Institute, University of Chicago, Chicago, Illinois
| | - Stephan Block
- Institut für Chemie und Biochemie, Freie Universität Berlin, Berlin, Germany
| | - Prerna Sharma
- Department of Physics, Indian Institute of Science, Bangalore, India; Department of Bioengineering, Indian Institute of Science, Bangalore, India
| | - Roland R Netz
- Fachbereich Physik, Freie Universität Berlin, Berlin, Germany.
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2
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Wei D, Quaranta G, Aubin-Tam ME, Tam DSW. The younger flagellum sets the beat for Chlamydomonas reinhardtii. eLife 2024; 13:e86102. [PMID: 38752724 PMCID: PMC11098555 DOI: 10.7554/elife.86102] [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: 01/11/2023] [Accepted: 04/03/2024] [Indexed: 05/18/2024] Open
Abstract
Eukaryotes swim with coordinated flagellar (ciliary) beating and steer by fine-tuning the coordination. The model organism for studying flagellate motility, Chlamydomonas reinhardtii, employs synchronous, breaststroke-like flagellar beating to swim, and it modulates the beating amplitudes differentially to steer. This strategy hinges on both inherent flagellar asymmetries (e.g. different response to chemical messengers) and such asymmetries being effectively coordinated in the synchronous beating. In C. reinhardtii, the synchrony of beating is known to be supported by a mechanical connection between flagella; however, how flagellar asymmetries persist in the synchrony remains elusive. For example, it has been speculated for decades that one flagellum leads the beating, as its dynamic properties (i.e. frequency, waveform, etc.) appear to be copied by the other one. In this study, we combine experiments, computations, and modeling efforts to elucidate the roles played by each flagellum in synchronous beating. With a non-invasive technique to selectively load each flagellum, we show that the coordinated beating essentially only responds to load exerted on the cis flagellum; and that such asymmetry in response derives from a unilateral coupling between the two flagella. Our results highlight a distinct role for each flagellum in coordination and have implication for biflagellates' tactic behaviors.
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Affiliation(s)
- Da Wei
- Department of Bionanoscience, Delft University of TechnologyDelftNetherlands
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of SciencesBeijingChina
| | - Greta Quaranta
- Laboratory for Aero and Hydrodynamics, Delft University of TechnologyDelftNetherlands
| | - Marie-Eve Aubin-Tam
- Department of Bionanoscience, Delft University of TechnologyDelftNetherlands
| | - Daniel SW Tam
- Laboratory for Aero and Hydrodynamics, Delft University of TechnologyDelftNetherlands
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3
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Fueki S, Kaneko T, Matsuki H, Hashimoto Y, Yoshida M, Isu A, Wakabayashi KI, Yoshimura K. Temperature-dependent augmentation of ciliary motility by the TRP2 channel in Chlamydomonas reinhardtii. Cytoskeleton (Hoboken) 2024. [PMID: 38426808 DOI: 10.1002/cm.21840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 01/22/2024] [Accepted: 02/07/2024] [Indexed: 03/02/2024]
Abstract
Temperature is a critical factor for living organisms. Many microorganisms migrate toward preferable temperatures, and this behavior is called thermotaxis. In this study, the molecular and physiological bases for thermotaxis are examined in Chlamydomonas reinhardtii. A mutant with knockout of a transient receptor potential (TRP) channel, trp2-3, showed defective thermotaxis. The swimming velocity and ciliary beat frequency of wild-type Chlamydomonas increase with temperature; however, this temperature-dependent enhancement of motility was almost absent in the trp2-3 mutant. Wild-type Chlamydomonas showed negative thermotaxis, but mutants deficient in the outer or inner dynein arm showed positive thermotaxis and a defect in temperature-dependent increase in swimming velocity, suggesting involvement of both dynein arms in thermotaxis.
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Affiliation(s)
- Shunta Fueki
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama, Japan
| | - Taro Kaneko
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama, Japan
| | - Haruka Matsuki
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama, Japan
| | - Yuki Hashimoto
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama, Japan
| | - Megumi Yoshida
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama, Japan
| | - Atsuko Isu
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Ken-Ichi Wakabayashi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
- Department of Industrial Life Sciences, Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, Japan
| | - Kenjiro Yoshimura
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama, Japan
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4
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Oshima D, Yoshida M, Saga K, Ito N, Tsuji M, Isu A, Watanabe N, Wakabayashi KI, Yoshimura K. Mechanoresponses mediated by the TRP11 channel in cilia of Chlamydomonas reinhardtii. iScience 2023; 26:107926. [PMID: 37790279 PMCID: PMC10543168 DOI: 10.1016/j.isci.2023.107926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/15/2023] [Accepted: 09/12/2023] [Indexed: 10/05/2023] Open
Abstract
Cilia are organelles involved in motility and sensory transduction, but how these two functions coexist has not been elucidated in depth. Here, the involvement of the ciliary transient receptor potential (TRP) channel TRP11 in mechanoresponses is studied in Chlamydomonas reinhardtii using a TRP11-knockout mutant. The mutant has defects in the conversion of the bending mode of the cilium from forward to reverse when tapped with a glass rod, the detachment of cilia when shear is applied, the increase in ciliary beat frequency upon application of mechanical agitation by vortex mixing, and the initiation of gliding while both cilia are attached in opposite directions to a glass surface. These observations indicate that TRP11 can perceive mechanical stimuli with distinct intensities and durations and induce various types of ciliary responses.
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Affiliation(s)
- Daichi Oshima
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama 337-8570, Japan
| | - Megumi Yoshida
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama 337-8570, Japan
| | - Kosuke Saga
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama 337-8570, Japan
| | - Neo Ito
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama 337-8570, Japan
| | - Miyu Tsuji
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama 337-8570, Japan
| | - Atsuko Isu
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama 226-8503, Japan
| | - Nobuo Watanabe
- Department of Bio-Science and Engineering, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama 337-8570, Japan
| | - Ken-ichi Wakabayashi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama 226-8503, Japan
- Department of Industrial Life Sciences, Faculty of Life Sciences, Kyoto Sangyo University, Kyoto 603-8555, Japan
| | - Kenjiro Yoshimura
- Department of Machinery and Control Systems, College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama 337-8570, Japan
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5
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Pivato M, Grenzi M, Costa A, Ballottari M. Compartment-specific Ca 2+ imaging in the green alga Chlamydomonas reinhardtii reveals high light-induced chloroplast Ca 2+ signatures. THE NEW PHYTOLOGIST 2023; 240:258-271. [PMID: 37488718 DOI: 10.1111/nph.19142] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 06/26/2023] [Indexed: 07/26/2023]
Abstract
To investigate the role of intracellular Ca2+ signaling in the perception and response mechanisms to light in unicellular microalgae, the genetically encoded ratiometric Ca2+ indicator Yellow Cameleon (YC3.6) was expressed in the model organism for green algae Chlamydomonas reinhardtii, targeted to cytosol, chloroplast, and mitochondria. Through in vivo single-cell confocal microscopy imaging, light-induced Ca2+ signaling was investigated in different conditions and different genotypes, including the photoreceptors mutants phot and acry. A genetically encoded H2 O2 sensor was also adopted to investigate the possible role of H2 O2 formation in light-dependent Ca2+ signaling. Light-dependent Ca2+ response was observed in Chlamydomonas reinhardtii cells only in the chloroplast as an organelle-autonomous response, influenced by light intensity and photosynthetic electron transport. The absence of blue and red-light photoreceptor aCRY strongly reduced the light-dependent chloroplast Ca2+ response, while the absence of the blue photoreceptor PHOT had no significant effects. A correlation between high light-induced chloroplast H2 O2 gradients and Ca2+ transients was drawn, supported by H2 O2 -induced chloroplast Ca2+ transients in the dark. In conclusion, different triggers are involved in the light-induced chloroplast Ca2+ signaling as saturation of the photosynthetic electron transport, H2 O2 formation, and aCRY-dependent light perception.
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Affiliation(s)
- Matteo Pivato
- Department of Biotechnology, University of Verona, Strada le Grazie 15, 37134, Verona, Italy
| | - Matteo Grenzi
- Department of Biosciences, University of Milan, Via Giovanni Celoria 26, 20133, Milan, Italy
| | - Alex Costa
- Department of Biosciences, University of Milan, Via Giovanni Celoria 26, 20133, Milan, Italy
- Institute of Biophysics, National Research Council of Italy (CNR), Milan, 20133, Italy
| | - Matteo Ballottari
- Department of Biotechnology, University of Verona, Strada le Grazie 15, 37134, Verona, Italy
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6
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Ewerling A, Maissl V, Wickstead B, May-Simera HL. Neofunctionalization of ciliary BBS proteins to nuclear roles is likely a frequent innovation across eukaryotes. iScience 2023; 26:106410. [PMID: 37034981 PMCID: PMC10074162 DOI: 10.1016/j.isci.2023.106410] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 07/20/2022] [Accepted: 03/10/2023] [Indexed: 03/17/2023] Open
Abstract
The eukaryotic BBSome is a transport complex within cilia and assembled by chaperonin-like BBS proteins. Recent work indicates nuclear functions for BBS proteins in mammals, but it is unclear how common these are in extant proteins or when they evolved. We screened for BBS orthologues across a diverse set of eukaryotes, consolidated nuclear association via signal sequence predictions and permutation analysis, and validated nuclear localization in mammalian cells via fractionation and immunocytochemistry. BBS proteins are-with exceptions-conserved as a set in ciliated species. Predictions highlight five most likely nuclear proteins and suggest that nuclear roles evolved independently of nuclear access during mitosis. Nuclear localization was confirmed in human cells. These findings suggest that nuclear BBS functions are potentially not restricted to mammals, but may be a common frequently co-opted eukaryotic feature. Understanding the functional spectrum of BBS proteins will help elucidating their role in gene regulation, development, and disease.
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Affiliation(s)
- Alexander Ewerling
- Institute of Molecular Physiology, Faculty of Biology, Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Vanessa Maissl
- Institute of Molecular Physiology, Faculty of Biology, Johannes Gutenberg-University Mainz, Mainz, Germany
| | - Bill Wickstead
- School of Life Sciences, University of Nottingham, Nottingham, UK
| | - Helen Louise May-Simera
- Institute of Molecular Physiology, Faculty of Biology, Johannes Gutenberg-University Mainz, Mainz, Germany
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7
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Pivato M, Ballottari M. Chlamydomonas reinhardtii cellular compartments and their contribution to intracellular calcium signalling. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:5312-5335. [PMID: 34077536 PMCID: PMC8318260 DOI: 10.1093/jxb/erab212] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 05/11/2021] [Indexed: 05/12/2023]
Abstract
Calcium (Ca2+)-dependent signalling plays a well-characterized role in the response to different environmental stimuli, in both plant and animal cells. In the model organism for green algae, Chlamydomonas reinhardtii, Ca2+ signals were reported to have a crucial role in different physiological processes, such as stress responses, photosynthesis, and flagella functions. Recent reports identified the underlying components of the Ca2+ signalling machinery at the level of specific subcellular compartments and reported in vivo imaging of cytosolic Ca2+ concentration in response to environmental stimuli. The characterization of these Ca2+-related mechanisms and proteins in C. reinhardtii is providing knowledge on how microalgae can perceive and respond to environmental stimuli, but also on how this Ca2+ signalling machinery has evolved. Here, we review current knowledge on the cellular mechanisms underlying the generation, shaping, and decoding of Ca2+ signals in C. reinhardtii, providing an overview of the known and possible molecular players involved in the Ca2+ signalling of its different subcellular compartments. The advanced toolkits recently developed to measure time-resolved Ca2+ signalling in living C. reinhardtii cells are also discussed, suggesting how they can improve the study of the role of Ca2+ signals in the cellular response of microalgae to environmental stimuli.
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Affiliation(s)
- Matteo Pivato
- Department of Biotechnology, University of Verona, Strada le Grazie 15, 37134 Verona, Italy
| | - Matteo Ballottari
- Department of Biotechnology, University of Verona, Strada le Grazie 15, 37134 Verona, Italy
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8
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Takano W, Hisabori T, Wakabayashi KI. Rapid estimation of cytosolic ATP concentration from the ciliary beating frequency in the green alga Chlamydomonas reinhardtii. J Biol Chem 2020; 296:100156. [PMID: 33273011 PMCID: PMC7857514 DOI: 10.1074/jbc.ra120.015263] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 12/01/2020] [Accepted: 12/03/2020] [Indexed: 11/06/2022] Open
Abstract
Determination of cellular ATP levels, a key indicator of metabolic status, is essential for the quantitative analysis of metabolism. The biciliate green alga Chlamydomonas reinhardtii is an excellent experimental organism to study ATP production pathways, including photosynthesis and respiration, particularly because it can be cultured either photoautotrophically or heterotrophically. Additionally, its cellular ATP concentration, [ATP], is reflected in the beating of its cilia. However, the methods currently used for quantifying the cellular ATP levels are time consuming or invasive. In this study, we established a rapid method for estimating cytosolic [ATP] from the ciliary beating frequency in C. reinhardtii. Using an improved method of motility reactivation in demembranated cell models, we obtained calibration curves for [ATP]–ciliary beating frequency over a physiological range of ATP concentrations. These curves allowed rapid estimation of the cytosolic [ATP] in live wild-type cells to be ∼2.0 mM in the light and ∼1.5 mM in the dark: values comparable to those obtained by other methods. Furthermore, we used this method to assess the effects of genetic mutations or inhibitors of photosynthesis or respiration quantitatively and noninvasively. This sensor-free method is a convenient tool for quickly estimating cytosolic [ATP] and studying the mechanism of ATP production in C. reinhardtii or other ciliated organisms.
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Affiliation(s)
- Wakako Takano
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan; School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Toru Hisabori
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan; School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Ken-Ichi Wakabayashi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan; School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan.
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9
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Amador GJ, Wei D, Tam D, Aubin-Tam ME. Fibrous Flagellar Hairs of Chlamydomonas reinhardtii Do Not Enhance Swimming. Biophys J 2020; 118:2914-2925. [PMID: 32502384 PMCID: PMC7300311 DOI: 10.1016/j.bpj.2020.05.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 04/06/2020] [Accepted: 04/27/2020] [Indexed: 01/18/2023] Open
Abstract
The flagella of Chlamydomonas reinhardtii possess fibrous ultrastructures of a nanometer-scale thickness known as mastigonemes. These structures have been widely hypothesized to enhance flagellar thrust; however, detailed hydrodynamic analysis supporting this claim is lacking. In this study, we present a comprehensive investigation into the hydrodynamic effects of mastigonemes using a genetically modified mutant lacking the fibrous structures. Through high-speed observations of freely swimming cells, we found the average and maximum swimming speeds to be unaffected by the presence of mastigonemes. In addition to swimming speeds, no significant difference was found for flagellar gait kinematics. After our observations of swimming kinematics, we present direct measurements of the hydrodynamic forces generated by flagella with and without mastigonemes. These measurements were conducted using optical tweezers, which enabled high temporal and spatial resolution of hydrodynamic forces. Through our measurements, we found no significant difference in propulsive flows due to the presence of mastigonemes. Direct comparison between measurements and fluid mechanical modeling revealed that swimming hydrodynamics were accurately captured without including mastigonemes on the modeled swimmer's flagella. Therefore, mastigonemes do not appear to increase the flagella's effective area while swimming, as previously thought. Our results refute the longstanding claim that mastigonemes enhance flagellar thrust in C. reinhardtii, and so, their function still remains enigmatic.
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Affiliation(s)
- Guillermo J Amador
- Laboratory for Aero and Hydrodynamics, Delft University of Technology, Delft, the Netherlands; Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, the Netherlands
| | - Da Wei
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, the Netherlands
| | - Daniel Tam
- Laboratory for Aero and Hydrodynamics, Delft University of Technology, Delft, the Netherlands.
| | - Marie-Eve Aubin-Tam
- Department of Bionanoscience, Kavli Institute of Nanoscience, Delft University of Technology, Delft, the Netherlands.
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10
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Detergent-extracted Volvox model exhibits an anterior-posterior gradient in flagellar Ca 2+ sensitivity. Proc Natl Acad Sci U S A 2018; 115:E1061-E1068. [PMID: 29311312 DOI: 10.1073/pnas.1715489115] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Volvox rousseletii is a multicellular spheroidal green alga containing ∼5,000 cells, each equipped with two flagella (cilia). This organism shows striking photobehavior without any known intercellular communication. To help understand how the behavior of flagella is regulated, we developed a method to extract the whole organism with detergent and reactivate its flagellar motility. Upon addition of ATP, demembranated flagella (axonemes) in the spheroids actively beat and the spheroids swam as if they were alive. Under Ca2+-free conditions, the axonemes assumed planar and asymmetrical waveforms and beat toward the posterior pole, as do live spheroids in the absence of light stimulation. In the presence of 10-6 M Ca2+, however, most axonemes beat three-dimensionally toward the anterior pole, similar to flagella in photostimulated live spheroids. This Ca2+-dependent change in flagellar beating direction was more conspicuous near the anterior pole of the spheroid, but was not observed near the posterior pole. This anterior-posterior gradient of flagellar Ca2+ sensitivity may explain the mechanism of V. rousseletii photobehavior.
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11
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González-Pleiter M, Rioboo C, Reguera M, Abreu I, Leganés F, Cid Á, Fernández-Piñas F. Calcium mediates the cellular response of Chlamydomonas reinhardtii to the emerging aquatic pollutant Triclosan. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2017; 186:50-66. [PMID: 28249228 DOI: 10.1016/j.aquatox.2017.02.021] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 02/17/2017] [Accepted: 02/19/2017] [Indexed: 06/06/2023]
Abstract
The present study was aimed at investigating the role of intracellular free calcium, [Ca2+]c, in the early cellular response of the green alga Chlamydomonas reinhardtii to the emergent pollutant Triclosan (13.8μM; 24h of exposure). There is a growing concern about the persistence and toxicity of this antimicrobial in aquatic environments, where non-target organisms such as C. reinhardtii, a primary producer of ecological relevance, might be severely impacted. A mechanistic study was undertaken which combined flow cytometry protocols, physiological as well as gene expression analysis. As an early response, Triclosan strongly altered [Ca2+]c homeostasis which could be prevented by prechelation with the intracellular calcium chelator BAPTA-AM. Triclosan induced ROS overproduction which ultimately leads to oxidative stress with loss of membrane integrity, membrane depolarization, photosynthesis inhibition and mitochondrial membrane depolarization; within this context, Triclosan also induced an increase in caspase 3/7 activity and altered the expression of metacaspase genes which are indicative of apoptosis. All these adverse outcomes were dependent on [Ca2+]c. Interestingly, an interconnection between [Ca2+]c alterations and increased ROS formation by Triclosan was found. Taken altogether these results shed light on the mechanisms behind Triclosan toxicity in the green alga Chlamydomonas reinhardtii and demonstrate the role of [Ca2+]c in mediating the observed toxicity.
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Affiliation(s)
- Miguel González-Pleiter
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Carmen Rioboo
- Laboratorio de Microbiología, Facultad de Ciencias, Universidad da Coruña, Campus de A Zapateira s/n, 15008 A Coruña, Spain
| | - María Reguera
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Isidro Abreu
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Francisco Leganés
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain
| | - Ángeles Cid
- Laboratorio de Microbiología, Facultad de Ciencias, Universidad da Coruña, Campus de A Zapateira s/n, 15008 A Coruña, Spain
| | - Francisca Fernández-Piñas
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
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12
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Calcium-Dependent Signalling Processes in Chlamydomonas. CHLAMYDOMONAS: MOLECULAR GENETICS AND PHYSIOLOGY 2017. [DOI: 10.1007/978-3-319-66365-4_8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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13
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Cho MK, Shin HS. Mechanotransduction-Induced Lipid Production System with High Robustness and Controllability for Microalgae. Sci Rep 2016; 6:32860. [PMID: 27609701 PMCID: PMC5016897 DOI: 10.1038/srep32860] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 08/15/2016] [Indexed: 12/16/2022] Open
Abstract
Microalgae lipids are a promising energy source, but current biochemical methods of lipid-inductions such as nitrogen deprivation have low process robustness and controllability. Recently, use of mechanotransduction based membrane distortion by applying compression stress in a 2D-microsystem was suggested as a way to overcome these limitations of biochemical induction. However, reproduction in large numbers of cells without cell death has been difficult to overcome because compression for direct membrane distortion reduces culture volume and leads to cell death due to nutrient deprivation. In this study, a mechanotransduction-induced lipid production (MDLP) system that redirects elastic microbeads to induce membrane distortion of microalgae with alleviating cell death was developed. This system resulted in accumulation of lipid in as little as 4 hr. Once compressed, porous microbeads absorb media and swell simultaneously while homogeneously inducing compression stress of microalgae. The absorbed media within beads could be supplied to adjacent cells and could minimize cell death from nutrient deficiency. All mechanotransduction was confirmed by measuring upregulation of calcium influx and Mat3 genes. The microbeads ensured robustness and controllability in repeated compression/de-compression processes. Overall, the MDLP system has potential for use as a fundamental biodiesel process that requires robustness and controllability.
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Affiliation(s)
- Myung Kwon Cho
- Department of Biological Engineering, Inha University, Incheon, 402-751, Korea
| | - Hwa Sung Shin
- Department of Biological Engineering, Inha University, Incheon, 402-751, Korea
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14
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Feng CY, Wei JF, Li YJ, Yang YS, Wang YH, Lu L, Zheng GX. An on-chip pollutant toxicity determination based on marine microalgal swimming inhibition. Analyst 2016; 141:1761-71. [DOI: 10.1039/c5an02384j] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Microfluidics using marine microalgal swimming behavior as a sensor signal were developed for a rapid and high-throughput determination of pollutant toxicity.
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Affiliation(s)
- Cheng-Yu Feng
- Chemical and Environmental Engineering Institute
- Dalian University
- Dalian
- China
- Microfluidic Research Institute
| | - Jun-Feng Wei
- Chemical and Environmental Engineering Institute
- Dalian University
- Dalian
- China
- Microfluidic Research Institute
| | - Ya-Jie Li
- Medical School
- Dalian University
- Dalian
- China
- Microfluidic Research Institute
| | - Yu-Suo Yang
- Chemical and Environmental Engineering Institute
- Dalian University
- Dalian
- China
- Microfluidic Research Institute
| | - Yun-Hua Wang
- Medical School
- Dalian University
- Dalian
- China
- Microfluidic Research Institute
| | - Ling Lu
- Medical School
- Dalian University
- Dalian
- China
- Microfluidic Research Institute
| | - Guo-Xia Zheng
- Chemical and Environmental Engineering Institute
- Dalian University
- Dalian
- China
- Microfluidic Research Institute
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15
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Moran Y, Barzilai MG, Liebeskind BJ, Zakon HH. Evolution of voltage-gated ion channels at the emergence of Metazoa. J Exp Biol 2015; 218:515-25. [DOI: 10.1242/jeb.110270] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Voltage-gated ion channels are large transmembrane proteins that enable the passage of ions through their pore across the cell membrane. These channels belong to one superfamily and carry pivotal roles such as the propagation of neuronal and muscular action potentials and the promotion of neurotransmitter secretion in synapses. In this review, we describe in detail the current state of knowledge regarding the evolution of these channels with a special emphasis on the metazoan lineage. We highlight the contribution of the genomic revolution to the understanding of ion channel evolution and for revealing that these channels appeared long before the appearance of the first animal. We also explain how the elucidation of channel selectivity properties and function in non-bilaterian animals such as cnidarians (sea anemones, corals, jellyfish and hydroids) can contribute to the study of channel evolution. Finally, we point to open questions and future directions in this field of research.
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Affiliation(s)
- Yehu Moran
- Department of Ecology, Evolution and Behavior, Alexander Silberman Institute of Life Sciences, Faculty of Science, Hebrew University of Jerusalem, Jerusalem 91904, Israel
| | - Maya Gur Barzilai
- Department of Molecular Biology and Ecology of Plants, George S. Wise Faculty of Life Sciences, Tel-Aviv University, Tel-Aviv 69978, Israel
| | - Benjamin J. Liebeskind
- Department of Integrative Biology and Center for Computational Biology and Bioinformatics, University of Texas, Austin, TX 78712, USA
| | - Harold H. Zakon
- Department of Integrative Biology and Center for Computational Biology and Bioinformatics, University of Texas, Austin, TX 78712, USA
- Department of Neuroscience, University of Texas at Austin, TX 78712, USA
- Josephine Bay Paul Center for Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA 02543, USA
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16
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Nicovich PR, Macartney EL, Whan RM, Crean AJ. Measuring sperm movement within the female reproductive tract using Fourier analysis. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2015; 21:256-263. [PMID: 25640702 DOI: 10.1017/s1431927614014627] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
The adaptive significance of variation in sperm phenotype is still largely unknown, in part due to the difficulties of observing and measuring sperm movement in its natural, selective environment (i.e., within the female reproductive tract). Computer-assisted sperm analysis systems allow objective and accurate measurement of sperm velocity, but rely on being able to track individual sperm, and are therefore unable to measure sperm movement in species where sperm move in trains or bundles. Here we describe a newly developed computational method for measuring sperm movement using Fourier analysis to estimate sperm tail beat frequency. High-speed time-lapse videos of sperm movement within the female tract of the neriid fly Telostylinus angusticollis were recorded, and a map of beat frequencies generated by converting the periodic signal of an intensity versus time trace at each pixel to the frequency domain using the Fourier transform. We were able to detect small decreases in sperm tail beat frequency over time, indicating the method is sensitive enough to identify consistent differences in sperm movement. Fourier analysis can be applied to a wide range of species and contexts, and should therefore facilitate novel exploration of the causes and consequences of variation in sperm movement.
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Affiliation(s)
- Philip R Nicovich
- 1ARC Centre of Excellence in Molecular Imaging,School of Medical Sciences,The University of New South Wales,Sydney,NSW 2052,Australia
| | - Erin L Macartney
- 3Evolution & Ecology Research Centre,School of Biological,Earth and Environmental Sciences,The University of New South Wales,Sydney,NSW 2052,Australia
| | - Renee M Whan
- 2Biomedical Imaging Facility,Mark Wainwright Analytical Centre,The University of New South Wales,Sydney,NSW 2052,Australia
| | - Angela J Crean
- 3Evolution & Ecology Research Centre,School of Biological,Earth and Environmental Sciences,The University of New South Wales,Sydney,NSW 2052,Australia
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17
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Abstract
Cilia are force-generating and -sensing organelles that serve as mechanical interfaces between the cell and the extracellular environment. Cilia are present in tissues that adaptively respond to mechanical loading and fluid flow, and defects in ciliary function can lead to diseases affecting these tissues. As might be expected for a mechanical interface, the formation of cilia is, itself, regulated by mechanical forces, and these links between mechanics and ciliary formation are providing new entry points for dissecting the regulatory pathways of ciliogenesis.
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Affiliation(s)
- Hiroaki Ishikawa
- Hiroaki Ishikawa and Wallace F. Marshall are affiliated with the Department of Biochemistry and Biophysics at the University of California San Francisco
| | - Wallace F Marshall
- Hiroaki Ishikawa and Wallace F. Marshall are affiliated with the Department of Biochemistry and Biophysics at the University of California San Francisco
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18
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Zheng GX, Li YJ, Qi LL, Liu XM, Wang H, Yu SP, Wang YH. Marine phytoplankton motility sensor integrated into a microfluidic chip for high-throughput pollutant toxicity assessment. MARINE POLLUTION BULLETIN 2014; 84:147-154. [PMID: 24882443 DOI: 10.1016/j.marpolbul.2014.05.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Revised: 05/07/2014] [Accepted: 05/08/2014] [Indexed: 06/03/2023]
Abstract
A microfluidic chip was designed to assess the toxicity of pollutants in a high-throughput way by using marine phytoplankton motility as a sensor signal. In this chip, multiple gradient generators (CGGs) with diffusible chambers enable large scale of dose-response bioassays to be performed in a simple way. Two mobile marine phytoplankton cells were confined on-chip and stimulated by 8 concentrations (generated by CGG) of Hg, Pb, Cu and phenol singly, as well as Cu and phenol jointly. CASA system was used to characterize motility by motile percentage (%MOT), curvilinear velocity (VCL), average path velocity (VAP) and straight line velocity (VSL). In all cases, dose-dependent inhibitions of motility were observed. In the present system, only 2h was needed to predict EC50. Thus, the developed microfluidic chip device was proved to be useful as a rapid/simple and high-throughput test method in marine pollution toxicity assessment.
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Affiliation(s)
- Guo-xia Zheng
- Chemical and Environmental Engineering Institute, Dalian University, Dalian, China; Microfluidic Research Institute, Dalian University, Dalian, China.
| | - Ya-jie Li
- Medical School, Dalian University, Dalian, China; Microfluidic Research Institute, Dalian University, Dalian, China
| | - Lin-lin Qi
- Chemical and Environmental Engineering Institute, Dalian University, Dalian, China; Medical School, Dalian University, Dalian, China
| | - Xian-ming Liu
- Microfluidic Research Institute, Dalian University, Dalian, China; Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian, China
| | - Hu Wang
- Chemical and Environmental Engineering Institute, Dalian University, Dalian, China; Microfluidic Research Institute, Dalian University, Dalian, China
| | - Shu-ping Yu
- Chemical and Environmental Engineering Institute, Dalian University, Dalian, China; Microfluidic Research Institute, Dalian University, Dalian, China
| | - Yun-hua Wang
- Medical School, Dalian University, Dalian, China; Microfluidic Research Institute, Dalian University, Dalian, China.
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19
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Min SK, Yoon GH, Joo JH, Sim SJ, Shin HS. Mechanosensitive physiology of Chlamydomonas reinhardtii under direct membrane distortion. Sci Rep 2014; 4:4675. [PMID: 24728350 PMCID: PMC3985077 DOI: 10.1038/srep04675] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 03/28/2014] [Indexed: 12/31/2022] Open
Abstract
Cellular membrane distortion invokes variations in cellular physiology. However, lack of an appropriate system to control the stress and facilitate molecular analyses has hampered progress of relevant studies. In this study, a microfluidic system that finely manipulates membrane distortion of Chlamydomonas reinhardtii (C. reinhardtii) was developed. The device facilitated a first-time demonstration that directs membrane distortion invokes variations in deflagellation, cell cycle, and lipid metabolism. C. reinhardtii showed a prolonged G1 phase with an extended total cell cycle time, and upregulated Mat3 regulated a cell size and cell cycle. Additionally, increased TAG compensated for the loss of cell mass. Overall, this study suggest that cell biology that requires direct membrane distortion can be realized using this system, and the implication of cell cycle with Mat3 expression of C. reinhardtii was first demonstrated. Finally, membrane distortion can be an attractive inducer for biodiesel production since it is reliable and robust.
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Affiliation(s)
- Seul Ki Min
- Department of Biological Engineering, Inha University, Incheon, 402-751, Korea
| | - Gwang Heum Yoon
- Department of Biological Engineering, Inha University, Incheon, 402-751, Korea
| | - Jung Hyun Joo
- Department of Biological Engineering, Inha University, Incheon, 402-751, Korea
| | - Sang Jun Sim
- Department of Chemical and Biological Engineering, Korea University, Seoul, 136-713, Korea
| | - Hwa Sung Shin
- Department of Biological Engineering, Inha University, Incheon, 402-751, Korea
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20
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Motiwalla MJ, Sequeira MP, D'Souza JS. Two calcium-dependent protein kinases from Chlamydomonas reinhardtii are transcriptionally regulated by nutrient starvation. PLANT SIGNALING & BEHAVIOR 2014; 9:e27969. [PMID: 24514873 PMCID: PMC4091517 DOI: 10.4161/psb.27969] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 01/22/2014] [Accepted: 01/23/2014] [Indexed: 05/21/2023]
Abstract
We report here, the transcriptional regulation of 2 Calcium Dependent Protein Kinases in response to nutrient starvation of Chlamydomonas reinhardtii vegetative cells. The CDPK proteins, CDPK1 and CDPK3; share 53% identity among themselves, a maximum of 57% and 52% to higher plants respectively and 42% to apicomplexan protozoans. We expressed a CDPK1-GFP fusion protein in the C. reinhardtii vegetative cells and showed its distribution both in the cell body and the membrane-matrix fraction of the flagella. The fusion protein exhibits mobility shift in the presence of Ca (2+), confirming its Ca (2+)-binding properties. To the best of our knowledge, this is the first report of transcriptional regulation of CDPKs from a unicellular chlorophyte in response to nutrient starvation namely acetate (A), phosphorus (P), and nitrogen (N).
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21
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Hansen TJ, Hondzo M, Mashek MT, Mashek DG, Lefebvre PA. Algal swimming velocities signal fatty acid accumulation. Biotechnol Bioeng 2012; 110:143-52. [DOI: 10.1002/bit.24619] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2012] [Revised: 07/12/2012] [Accepted: 07/17/2012] [Indexed: 11/05/2022]
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22
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The DPY-30 domain and its flanking sequence mediate the assembly and modulation of flagellar radial spoke complexes. Mol Cell Biol 2012; 32:4012-24. [PMID: 22851692 DOI: 10.1128/mcb.06602-11] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
RIIa is known as the dimerization and docking (D/D) domain of the cyclic AMP (cAMP)-dependent protein kinase. However, numerous molecules, including radial spoke protein 2 (RSP2) in Chlamydomonas flagella, also contain an RIIa or a similar DPY-30 domain. To elucidate new roles of D/D domain-containing proteins, we investigated a panel of RSP2 mutants. An RSP2 mutant had paralyzed flagella defective in RSP2 and multiple subunits near the spokehead. New transgenic strains lacking only the DPY-30 domain in RSP2 were also paralyzed. In contrast, motility was restored in strains that lacked only RSP2's calmodulin-binding C-terminal region. These cells swam normally in dim light but could not maintain typical swimming trajectories under bright illumination. In both deletion transgenic strains, the subunits near the spokehead were restored, but their firm attachment to the spokestalk required the DPY-30 domain. We postulate that the DPY-30-helix dimer is a conserved two-prong linker, required for normal motility, organizing duplicated subunits in the radial spoke stalk and formation of a symmetrical spokehead. Further, the dispensable calmodulin-binding region appears to fine-tune the spokehead for regulation of "steering" motility in the green algae. Thus, in general, D/D domains may function to localize molecular modules for both the assembly and modulation of macromolecular complexes.
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23
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Nakano I, Fujiwara R, Wada M, Shingyoji C. Effects of iodide on the coupling between ATP hydrolysis and motile activity in axonemal dynein. Cytoskeleton (Hoboken) 2011; 68:279-89. [PMID: 21520430 DOI: 10.1002/cm.20511] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2010] [Revised: 11/29/2010] [Accepted: 04/07/2011] [Indexed: 11/08/2022]
Abstract
Dynein transduces the chemical energy of ATP hydrolysis into mechanical work through conformational changes. To identify the factors governing the coupling between the ATPase activity and the motile activity of the dynein molecule, we examined the effects of potassium iodide, which can unfold protein tertiary structures, on dynein activity in reactivated sea urchin sperm flagella. The presence of low concentrations of KI (0.05-0.1 M) in the reactivating solution did not influence the stable beating of demembranated flagella at 0.02-1 mM ATP, when the total concentration of potassium was kept at 0.15 M by adding K-acetate. However, double-reciprocal plots of ATP concentration and beat frequency showed a mixed type of inhibition by KI, indicating the possibility that KI inhibits the ATP hydrolysis and decreases the maximum sliding velocity. The ATPase activity of 21S dynein with or without microtubules did not decrease with the KI concentration. In the elastase-treated axonemes, KI decreased the velocity of sliding disintegration, while it increased the frequency of occurrence of axonemes showing no sliding. This may be related to some defect in the coordination of dynein activities. On 21S dynein adsorbed on a glass surface, however, the velocity of microtubule sliding was increased by KI, while KI lowered the dynein-microtubule affinity. The velocity further increased under lower salt conditions enhancing the dynein-microtubule interactions. The results suggest the importance of organized regulation of the dynamic states of dynein-microtubule interactions through the stalk for the coupling between the ATPase activity and the motile activity of dynein in beating flagella.
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Affiliation(s)
- Izumi Nakano
- Department of Biological Sciences, Graduate School of Science, University of Tokyo, Hongo, Tokyo 113-0033, Japan
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24
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Daiker V, Häder DP, Richter PR, Lebert M. The involvement of a protein kinase in phototaxis and gravitaxis of Euglena gracilis. PLANTA 2011; 233:1055-1062. [PMID: 21286747 DOI: 10.1007/s00425-011-1364-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Accepted: 01/14/2011] [Indexed: 05/30/2023]
Abstract
The unicellular flagellate Euglena gracilis shows positive phototaxis at low-light intensities (<10 W/m(2)) and a negative one at higher irradiances (>10 W/m(2)). Phototaxis is based on blue light-activated adenylyl cyclases, which produce cAMP upon irradiation. In the absence of light the cells swim upward in the water column (negative gravitaxis). The results of sounding rocket campaigns and of a large number of ground experiments led to the following model of signal perception and transduction in gravitaxis of E. gracilis: The body of the cell is heavier than the surrounding medium, sediments and thereby exerts a force onto the lower membrane. Upon deviation from a vertical swimming path mechano-sensitive ion channels are activated. Calcium is gated inwards which leads to an increase in the intracellular calcium concentration and causes a change of the membrane potential. After influx, calcium activates one of several calmodulins found in Euglena, which in turn activates an adenylyl cyclase (different from the one involved in phototaxis) to produce cAMP from ATP. One further element in the sensory transduction chain of both phototaxis and gravitaxis is a specific protein kinase A. We found five different protein kinases A in E. gracilis. The blockage of only one of these (PK.4, accession No. EU935859) by means of RNAi inhibited both phototaxis and gravitaxis, while inhibition of the other four affected neither phototaxis nor gravitaxis. It is assumed that cAMP directly activates this protein kinase A which may in turn phosphorylate a protein involved in the flagellar beating mechanism.
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Affiliation(s)
- Viktor Daiker
- Department of Biology, Cell Biology Division, Friedrich-Alexander University, Staudtstr. 5, 91058 Erlangen, Germany
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25
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King SM. Sensing the mechanical state of the axoneme and integration of Ca2+ signaling by outer arm dynein. Cytoskeleton (Hoboken) 2010; 67:207-13. [PMID: 20186692 DOI: 10.1002/cm.20445] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Axonemal dyneins have been demonstrated to monitor the mechanical state of the axoneme and must also alter activity in response to various signaling pathways. The central pair/radial spoke systems are clearly involved in controlling inner dynein arm function; however, the mechanisms by which the outer dynein arm transduces regulatory signals appear quite distinct at the molecular level. In Chlamydomonas, these regulatory components include thioredoxins involved in response to redox changes, molecules that tether the gamma heavy-chain motor unit to the A-tubule of the outer doublet and a Ca(2+)-binding protein that controls the structure of the gamma heavy-chain N-terminal domain. Together, these studies now suggest that the gamma heavy chain acts as a key regulatory node for controlling outer arm function in response to alterations in curvature and ligand binding. Furthermore, they allow us to propose a testable molecular mechanism by which altered Ca(2+) levels might lead to a change in ciliary waveform by controlling whether one heavy chain of outer arm dynein acts as a microtubule translocase or as an ATP-dependent brake that limits the amount of interdoublet sliding.
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Affiliation(s)
- Stephen M King
- Department of Molecular, Microbial and Structural Biology, University of Connecticut Health Center, Farmington, Connecticut 06030-3305, USA.
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26
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Bloodgood RA. Sensory reception is an attribute of both primary cilia and motile cilia. J Cell Sci 2010; 123:505-9. [PMID: 20144998 DOI: 10.1242/jcs.066308] [Citation(s) in RCA: 140] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
A recent cluster of papers has shown that motile cilia in the respiratory and reproductive tracts of humans and other mammals can exhibit sensory functions, a function previously attributed primarily to non-motile primary cilia. This leads to a new paradigm that all cilia and flagella (both motile and primary) can mediate sensory functions. However, examination of the literature shows that evidence of sensory functions of motile cilia and flagella is widespread in studies of invertebrates, and extends as back as far as 1899. In this Opinion article, I review the recent and historical findings that motile cilia have a variety of sensory functions, and discuss how this concept has in fact been evolving for the past century.
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Affiliation(s)
- Robert A Bloodgood
- Department of Cell Biology, University of Virginia School of Medicine, Charlottesville, VA 22908-0732, USA.
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27
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Abstract
Eukaryotic flagella and cilia are alternative names, for the slender cylindrical protrusions of a cell (240nm diameter, approximately 12,800nm-long in Chlamydomonas reinhardtii) that propel a cell or move fluid. Cilia are extraordinarily successful complex organelles abundantly found in animals performing many tasks. They play a direct or developmental role in the sensors of fluid flow, light, sound, gravity, smells, touch, temperature, and taste in mammals. The failure of cilia can lead to hydrocephalus, infertility, and blindness. However, in spite of their large role in human function and pathology, there is as yet no consensus on how cilia beat and perform their many functions, such as moving fluids in brain ventricles and lungs and propelling and steering sperm, larvae, and many microorganisms. One needs to understand and analyze ciliary beating and its hydrodynamic interactions. This chapter provides a guide for measuring, analyzing, and interpreting ciliary behavior in various contexts studied in the model system of Chlamydomonas. It describes: (1) how cilia work as self-organized beating structures (SOBSs), (2) the overlaid control in the cilia that optimizes the SOBS to achieve cell dispersal, phototaxis steering, and avoidance of obstacles, (3) the assay of a model intracellular signal processing system that responds to multiple external and internal inputs, choosing mode of behavior and then controlling the cilia, (4) how cilia sense their environment, and (5) potentially an assay of ciliary performance for toxicology or medical assessment.
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Affiliation(s)
- Kenneth W Foster
- Department of Physics, Syracuse University, Syracuse, New York 13244-1130, USA
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