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Cartwright JHE. Quantum noise may limit the mechanosensory sensitivity of cilia in the left-right organizer of the vertebrate bodyplan. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2023; 180-181:83-86. [PMID: 37137357 DOI: 10.1016/j.pbiomolbio.2023.04.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 04/19/2023] [Accepted: 04/26/2023] [Indexed: 05/05/2023]
Abstract
Could nature be harnessing quantum mechanics in cilia to optimize the sensitivity of the mechanism of left-right symmetry breaking during development in vertebrates? I evaluate whether mechanosensing - i.e., the detection of a left-right asymmetric signal through mechanical stimulation of sensory cilia, as opposed to biochemical signalling - might be functioning in the embryonic left-right organizer of the vertebrate bodyplan through quantum mechanics. I conclude that there is a possible role for quantum biology in mechanosensing in cilia. The system may not be limited by classical thermal noise, but instead by quantum noise, with an amplification process providing active cooling.
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Affiliation(s)
- Julyan H E Cartwright
- Instituto Andaluz de Ciencias de la Tierra, CSIC-Universidad de Granada, 18100, Armilla, Granada, Spain; Instituto Carlos I de Física Teórica y Computacional, Universidad de Granada, 18071, Granada, Spain.
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2
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Yu T, Matsuda M. Epb41l5 interacts with Iqcb1 and regulates ciliary function in zebrafish embryos. J Cell Sci 2020; 133:jcs240648. [PMID: 32501287 PMCID: PMC7338265 DOI: 10.1242/jcs.240648] [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: 10/21/2019] [Accepted: 05/13/2020] [Indexed: 11/20/2022] Open
Abstract
Erythrocyte protein band 4.1 like 5 (EPB41L5) is an adaptor protein beneath the plasma membrane that functions to control epithelial morphogenesis. Here we report a previously uncharacterized role of EPB41L5 in controlling ciliary function. We found that EPB41L5 forms a complex with IQCB1 (previously known as NPHP5), a ciliopathy protein. Overexpression of EPB41L5 reduced IQCB1 localization at the ciliary base in cultured mammalian epithelial cells. Conversely, epb41l5 knockdown increased IQCB1 localization at the ciliary base. epb41l5-deficient zebrafish embryos or embryos expressing C-terminally modified forms of Epb41l5 developed cilia with reduced motility and exhibited left-right patterning defects, an outcome of abnormal ciliary function. We observed genetic synergy between epb41l5 and iqcb1. Moreover, EPB41L5 decreased IQCB1 interaction with CEP290, another ciliopathy protein and a component of the ciliary base and centrosome. Together, these observations suggest that EPB41L5 regulates the composition of the ciliary base and centrosome through IQCB1 and CEP290.
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Affiliation(s)
- Tiffany Yu
- Department of Cell Biology and Molecular Medicine, Rutgers New Jersey Medical School, Newark, NJ 07302, USA
| | - Miho Matsuda
- Department of Cell Biology and Molecular Medicine, Rutgers New Jersey Medical School, Newark, NJ 07302, USA
- Department of Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
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3
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Cicuta P. The use of biophysical approaches to understand ciliary beating. Biochem Soc Trans 2020; 48:221-229. [PMID: 31922188 PMCID: PMC7054749 DOI: 10.1042/bst20190571] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Revised: 11/27/2019] [Accepted: 12/09/2019] [Indexed: 11/25/2022]
Abstract
Motile cilia are a striking example of the functional cellular organelle, conserved across all the eukaryotic species. Motile cilia allow the swimming of cells and small organisms and transport of liquids across epithelial tissues. Whilst the molecular structure is now very well understood, the dynamics of cilia is not well established either at the single cilium level nor at the level of collective beating. Indeed, a full understanding of this requires connecting together behaviour across various lengthscales, from the molecular to the organelle, then at the cellular level and up to the tissue scale. Aside from the fundamental interest in this system, understanding beating is important to elucidate aspects of embryonic development and a variety of health conditions from fertility to genetic and infectious diseases of the airways.
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Affiliation(s)
- Pietro Cicuta
- Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE, U.K
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4
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Cartwright JHE, Piro O, Tuval I. Chemosensing versus mechanosensing in nodal and Kupffer's vesicle cilia and in other left-right organizer organs. Philos Trans R Soc Lond B Biol Sci 2019; 375:20190566. [PMID: 31884912 DOI: 10.1098/rstb.2019.0566] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
How is sensing carried out by cilia in the mouse node, zebrafish Kupffer's vesicle and similar left-right (LR) organizer organs in other species? Two possibilities have been put forward. In the former, cilia would detect some chemical species in the fluid; in the latter, they would detect fluid flow. In either case, the hypothesis is that an imbalance would be detected between this signalling coming from cilia on the left and right sides of the organizer, which would initiate a cascade of signals leading ultimately to the breaking of LR symmetry in the developing body plan of the organism. We review the evidence for both hypotheses. This article is part of the Theo Murphy meeting issue 'Unity and diversity of cilia in locomotion and transport'.
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Affiliation(s)
- Julyan H E Cartwright
- Instituto Andaluz de Ciencias de la Tierra, CSIC-Universidad de Granada, 18100 Armilla, Granada, Spain.,Instituto Carlos I de Física Teórica y Computacional, Universidad de Granada, 18071 Granada, Spain
| | - Oreste Piro
- Departamento de Física, Universitat de les Illes Balears, 07122 Palma de Mallorca, Spain
| | - Idan Tuval
- Departamento de Física, Universitat de les Illes Balears, 07122 Palma de Mallorca, Spain.,Mediterranean Institute for Advanced Studies, CSIC-Universitat de les Illes Balears, 07190 Mallorca, Spain
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5
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Montague TG, Schier AF. Vg1-Nodal heterodimers are the endogenous inducers of mesendoderm. eLife 2017; 6:28183. [PMID: 29140251 PMCID: PMC5745085 DOI: 10.7554/elife.28183] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 10/13/2017] [Indexed: 12/03/2022] Open
Abstract
Nodal is considered the key inducer of mesendoderm in vertebrate embryos and embryonic stem cells. Other TGF-beta-related signals, such as Vg1/Dvr1/Gdf3, have also been implicated in this process but their roles have been unclear or controversial. Here we report that zebrafish embryos without maternally provided vg1 fail to form endoderm and head and trunk mesoderm, and closely resemble nodal loss-of-function mutants. Although Nodal is processed and secreted without Vg1, it requires Vg1 for its endogenous activity. Conversely, Vg1 is unprocessed and resides in the endoplasmic reticulum without Nodal, and is only secreted, processed and active in the presence of Nodal. Co-expression of Nodal and Vg1 results in heterodimer formation and mesendoderm induction. Thus, mesendoderm induction relies on the combination of two TGF-beta-related signals: maternal and ubiquitous Vg1, and zygotic and localized Nodal. Modeling reveals that the pool of maternal Vg1 enables rapid signaling at low concentrations of zygotic Nodal. All animals begin life as just one cell – a fertilized egg. In order to make a recognizable adult, each embryo needs to make the three types of tissue that will eventually form all of the organs: endoderm, which will form the internal organs; mesoderm, which will form the muscle and bones; and ectoderm, which will generate the skin and nervous system. All vertebrates – animals with backbones like fish and humans – use the so-called Nodal signaling pathway to make the endoderm and mesoderm. Nodal is a signaling molecule that binds to receptors on the surface of cells. If Nodal binds to a receptor on a cell, it instructs that cell to become endoderm or mesoderm. As such, Nodal is critical for vertebrate life. However, there has been a 30-year debate in the field of developmental biology about whether a protein called Vg1, which has a similar molecular structure as Nodal, plays a role in the early development of vertebrates. Zebrafish are often used to study animal development, and Montague and Schier decided to test whether these fish need the gene for Vg1 (also known as Gdf3) by deleting it using a genome editing technique called CRISPR/Cas9. It turns out that female zebrafish can survive without this gene. Yet, when the offspring of these females do not inherit the instructions to make Vg1 from their mothers, they fail to form the endoderm and mesoderm. This means that the embryos do not have hearts, blood or other internal organs, and they die within three days. Two other groups of researchers have independently reported similar results. The findings reveal that Vg1 is critical for the Nodal signaling pathway to work in zebrafish. Montague and Schier then showed that, in this pathway, Nodal does not activate its receptors on its own. Instead, Nodal must interact with Vg1, and it is this Nodal-Vg1 complex that activates receptors, and instructs cells to become endoderm and mesoderm. Scientists currently use the Nodal signaling pathway to induce human embryonic stem cells growing in the laboratory to become mesoderm and endoderm. As such, these new findings could ultimately help researchers to grow tissues and organs for human patients.
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Affiliation(s)
- Tessa G Montague
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States
| | - Alexander F Schier
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, United States.,Center for Brain Science, Harvard University, Cambridge, United States.,Broad Institute of MIT and Harvard, Cambridge, United States.,Harvard Stem Cell Institute, Cambridge, United States.,FAS Center for Systems Biology, Harvard University, Cambridge, United States
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6
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Lozoya OA, Gilchrist CL, Guilak F. Universally Conserved Relationships between Nuclear Shape and Cytoplasmic Mechanical Properties in Human Stem Cells. Sci Rep 2016; 6:23047. [PMID: 26976044 PMCID: PMC4792134 DOI: 10.1038/srep23047] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 02/25/2016] [Indexed: 12/22/2022] Open
Abstract
The ability of cells to proliferate, differentiate, transduce extracellular signals and assemble tissues involves structural connections between nucleus and cytoskeleton. Yet, how the mechanics of these connections vary inside stem cells is not fully understood. To address those questions, we combined two-dimensional particle-tracking microrheology and morphological measures using variable reduction techniques to measure whether cytoplasmic mechanics allow for discrimination between different human adherent stem cell types and across different culture conditions. Here we show that nuclear shape is a quantifiable discriminant of mechanical properties in the perinuclear cytoskeleton (pnCSK) of various stem cell types. Also, we find the pnCSK is a region with different mechanical properties than elsewhere in the cytoskeleton, with heterogeneously distributed locations exhibiting subdiffusive features, and which obeys physical relations conserved among various stem cell types. Finally, we offer a prospective basis to discriminate between stem cell types by coupling perinuclear mechanical properties to nuclear shape.
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Affiliation(s)
- Oswaldo A Lozoya
- Epigenetics and Stem Cell Biology Laboratory, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA
| | | | - Farshid Guilak
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA.,Departments of Orthopaedic Surgery, Biomedical Engineering, and Developmental Biology, Washington University in St. Louis, St. Louis, MO 63110, USA.,Shriners Hospitals for Children - St. Louis, St. Louis, MO 63110, USA
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7
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Jonas S, Zhou E, Deniz E, Huang B, Chandrasekera K, Bhattacharya D, Wu Y, Fan R, Deserno TM, Khokha MK, Chomaa MA. A novel approach to quantifying ciliary physiology: microfluidic mixing driven by a ciliated biological surface. LAB ON A CHIP 2013; 13:4160-4163. [PMID: 23970350 PMCID: PMC3856250 DOI: 10.1039/c3lc50571e] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
From the lungs to the central nervous system, cilia-driven fluid flow plays a fundamental role in many facets of life. Yet, there are few quantitative methods for analysing the function of ciliated surfaces. Here, we report a novel microfluidic approach for quantifying the performance of a ciliated surface using mixing performance as an integrated readout.
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Affiliation(s)
- Stephan Jonas
- Dept. of Diagnostic Radiology, Yale University, New Haven, CT, USA
- Dept. of Medical Informatics, RWTH Aachen University, Pauwelsstr. 30, Aachen, Germany
| | - Elaine Zhou
- Dept. of Diagnostic Radiology, Yale University, New Haven, CT, USA
- Dept. of Biomedical Engineering, Yale University
| | | | | | | | | | - Yu Wu
- Dept. of Biomedical Engineering, Yale University
| | - Rong Fan
- Dept. of Biomedical Engineering, Yale University
| | - Thomas M. Deserno
- Dept. of Medical Informatics, RWTH Aachen University, Pauwelsstr. 30, Aachen, Germany
| | - Mustafa K. Khokha
- Dept. of Pediatrics, Yale University
- Dept. of Genetics, Yale University
| | - Michael A. Chomaa
- Dept. of Biomedical Engineering, Yale University
- Dept. of Pediatrics, Yale University
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8
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Norris DP. Cilia, calcium and the basis of left-right asymmetry. BMC Biol 2012; 10:102. [PMID: 23256866 PMCID: PMC3527145 DOI: 10.1186/1741-7007-10-102] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Accepted: 12/14/2012] [Indexed: 01/09/2023] Open
Abstract
The clockwise rotation of cilia in the developing mammalian embryo drives a leftward flow of liquid; this genetically regulated biophysical force specifies left-right asymmetry of the mammalian body. How leftward flow is interpreted and information propagated to other tissues is the subject of debate. Four recent papers have shed fresh light on the possible mechanisms.
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Affiliation(s)
- Dominic P Norris
- Mammalian Genetics Unit, MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, UK.
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9
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Hirokawa N, Tanaka Y, Okada Y. Cilia, KIF3 molecular motor and nodal flow. Curr Opin Cell Biol 2012; 24:31-9. [PMID: 22285930 DOI: 10.1016/j.ceb.2012.01.002] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Revised: 12/29/2011] [Accepted: 01/07/2012] [Indexed: 01/24/2023]
Abstract
The establishment of left-right asymmetry during development of vertebrate embryos depends on leftward flow in the nodal cavity. The flow is produced by the rotational movement of the posteriorly tilted nodal cilia. However, it remains poorly understood how the nodal cilia are tilted posteriorly, and how the directionality of the flow is translated into gene expression patterns in the embryo. Recent studies have identified signaling molecules involved in these processes. First, planar cell polarity signaling has been shown to be involved in the posterior positioning of the basal bodies of nodal cilia, which leads to the posterior tilting of their rotation axes. Second, identification of putative receptors and signaling molecules suggests a link between the signaling molecules delivered by the nodal flow, and downstream signaling in the cells surrounding the nodal cavity and the lateral plate mesoderm.
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Affiliation(s)
- Nobutaka Hirokawa
- Department of Cell Biology and Anatomy, Graduate School of Medicine, University of Tokyo, Hongo, Tokyo 113-0033, Japan.
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10
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Farnum CE, Wilsman NJ. Axonemal positioning and orientation in three-dimensional space for primary cilia: what is known, what is assumed, and what needs clarification. Dev Dyn 2011; 240:2405-31. [PMID: 22012592 PMCID: PMC3278774 DOI: 10.1002/dvdy.22756] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Two positional characteristics of the ciliary axoneme--its location on the plasma membrane as it emerges from the cell, and its orientation in three-dimensional (3D) space--are known to be critical for optimal function of actively motile cilia (including nodal cilia), as well as for modified cilia associated with special senses. However, these positional characteristics have not been analyzed to any significant extent for primary cilia. This review briefly summarizes the history of knowledge of these two positional characteristics across a wide spectrum of cilia, emphasizing their importance for proper function. Then the review focuses what is known about these same positional characteristics for primary cilia in all major tissue types where they have been reported. The review emphasizes major areas that would be productive for future research for understanding how positioning and 3D orientation of primary cilia may be related to their hypothesized signaling roles within different cellular populations.
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Affiliation(s)
- Cornelia E Farnum
- Department of Biomedical Sciences, Cornell University, Ithaca, New York 14853, USA.
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11
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12
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Stevens J, Ermakov A, Braganca J, Hilton H, Underhill P, Bhattacharya S, Brown NA, Norris DP. Analysis of the asymmetrically expressed Ablim1 locus reveals existence of a lateral plate Nodal-independent left sided signal and an early, left-right independent role for nodal flow. BMC DEVELOPMENTAL BIOLOGY 2010; 10:54. [PMID: 20487527 PMCID: PMC2885315 DOI: 10.1186/1471-213x-10-54] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2009] [Accepted: 05/20/2010] [Indexed: 11/10/2022]
Abstract
BACKGROUND Vertebrates show clear asymmetry in left-right (L-R) patterning of their organs and associated vasculature. During mammalian development a cilia driven leftwards flow of liquid leads to the left-sided expression of Nodal, which in turn activates asymmetric expression of the transcription factor Pitx2. While Pitx2 asymmetry drives many aspects of asymmetric morphogenesis, it is clear from published data that additional asymmetrically expressed loci must exist. RESULTS A L-R expression screen identified the cytoskeletally-associated gene, actin binding lim protein 1 (Ablim1), as asymmetrically expressed in both the node and left lateral plate mesoderm (LPM). LPM expression closely mirrors that of Nodal. Significantly, Ablim1 LPM asymmetry was detected in the absence of detectable Nodal. In the node, Ablim1 was initially expressed symmetrically across the entire structure, resolving to give a peri-nodal ring at the headfold stage in a flow and Pkd2-dependent manner. The peri-nodal ring of Ablim1 expression became asymmetric by the mid-headfold stage, showing stronger right than left-sided expression. Node asymmetry became more apparent as development proceeded; expression retreated in an anticlockwise direction, disappearing first from the left anterior node. Indeed, at early somite stages Ablim1 shows a unique asymmetric expression pattern, in the left lateral plate and to the right side of the node. CONCLUSION Left LPM Ablim1 is expressed in the absence of detectable LPM Nodal, clearly revealing existence of a Pitx2 and Nodal-independent left-sided signal in mammals. At the node, a previously unrecognised action of early nodal flow and Pkd2 activity, within the pit of the node, influences gene expression in a symmetric manner. Subsequent Ablim1 expression in the peri-nodal ring reveals a very early indication of L-R asymmetry. Ablim1 expression analysis at the node acts as an indicator of nodal flow. Together these results make Ablim1 a candidate for controlling aspects of L-R identity and patterning.
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Affiliation(s)
- Jonathan Stevens
- MRC Mammalian Genetics Unit, MRC Harwell, Harwell Science and Innovation Campus, Oxfordshire, OX11 0RD, UK
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13
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Kotar J, Leoni M, Bassetti B, Lagomarsino MC, Cicuta P. Hydrodynamic synchronization of colloidal oscillators. Proc Natl Acad Sci U S A 2010; 107:7669-73. [PMID: 20385848 PMCID: PMC2867893 DOI: 10.1073/pnas.0912455107] [Citation(s) in RCA: 145] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Two colloidal spheres are maintained in oscillation by switching the position of an optical trap when a sphere reaches a limit position, leading to oscillations that are bounded in amplitude but free in phase and period. The interaction between the oscillators is only through the hydrodynamic flow induced by their motion. We prove that in the absence of stochastic noise the antiphase dynamical state is stable, and we show how the period depends on coupling strength. Both features are observed experimentally. As the natural frequencies of the oscillators are made progressively different, the coordination is quickly lost. These results help one to understand the origin of hydrodynamic synchronization and how the dynamics can be tuned. Cilia and flagella are biological systems coupled hydrodynamically, exhibiting dramatic collective motions. We propose that weakly correlated phase fluctuations, with one of the oscillators typically processing the other, are characteristic of hydrodynamically coupled systems in the presence of thermal noise.
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Affiliation(s)
- Jurij Kotar
- Cavendish Laboratory and Nanoscience Center, University of Cambridge, JJ Thomson Avenue, CB3 0HE Cambridge, United Kingdom
| | - Marco Leoni
- Cavendish Laboratory and Nanoscience Center, University of Cambridge, JJ Thomson Avenue, CB3 0HE Cambridge, United Kingdom
- Dipartimento di Fisica and Istituto Nazionale di Fisica Nucleare, Università degli Studi di Milano, sez. Milano, Via Celoria 16, 20100 Milan, Italy
- Department of Mathematics, University of Bristol, Bristol, BS8 1TW, United Kingdom; and
| | - Bruno Bassetti
- Dipartimento di Fisica and Istituto Nazionale di Fisica Nucleare, Università degli Studi di Milano, sez. Milano, Via Celoria 16, 20100 Milan, Italy
| | - Marco Cosentino Lagomarsino
- Dipartimento di Fisica and Istituto Nazionale di Fisica Nucleare, Università degli Studi di Milano, sez. Milano, Via Celoria 16, 20100 Milan, Italy
- Genomic Physics Group, FRE 3214 Centre National de la Recherche Scientifique “Microorganism Genomics” and University Pierre et Marie Curie, 15, rue de l’École de Médecine, Paris, France
| | - Pietro Cicuta
- Cavendish Laboratory and Nanoscience Center, University of Cambridge, JJ Thomson Avenue, CB3 0HE Cambridge, United Kingdom
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14
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Vogel P, Read R, Hansen GM, Freay LC, Zambrowicz BP, Sands AT. Situs inversus in Dpcd/Poll-/-, Nme7-/- , and Pkd1l1-/- mice. Vet Pathol 2010; 47:120-31. [PMID: 20080492 DOI: 10.1177/0300985809353553] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Situs inversus (SI) is a congenital condition characterized by left-right transposition of thoracic and visceral organs and associated vasculature. The usual asymmetrical positioning of organs is established early in development in a transient structure called the embryonic node. The 2-cilia hypothesis proposes that 2 kinds of primary cilia in the embryonic node determine left-right asymmetry: motile cilia that generate a leftward fluid flow, and immotile mechanosensory cilia that respond to the flow. Here, we describe 3 mouse SI models that provide support for the 2-cilia hypothesis. In addition to having SI, Dpcd/Poll(-/-) mice (for: deleted in a mouse model of primary ciliary dyskinesia) and Nme7(-/-) mice (for: nonmetastatic cells 7) had lesions consistent with deficient ciliary motility: Hydrocephalus, sinusitis, and male infertility developed in Dpcd/Poll(-/-) mice, whereas hydrocephalus and excessive nasal exudates were seen in Nme7(-/-) mice. In contrast, the absence of respiratory tract lesions, hydrocephalus, and male infertility in Pkd1l1(-/-) mice (for: polycystic kidney disease 1 like 1) suggested that dysfunction of motile cilia was not involved in the development of SI in this line. Moreover, the gene Pkd1l1 has considerable sequence similarity with Pkd1 (for: polycystic kidney disease 1), which encodes a protein (polycystin-1) that is essential for the mechanosensory function of immotile primary cilia in the kidney. The markedly reduced viability of Pkd1l1(-/-) mice is somewhat surprising given the absence of any detected abnormalities (other than SI) in surviving Pkd1l1(-/-) mice subjected to a comprehensive battery of phenotype-screening exams. However, the heart and great vessels of Pkd1l1(-/-) mice were not examined, and it is possible that the decreased viability of Pkd1l1(-/-) mice is due to undiagnosed cardiovascular defects associated with heterotaxy.
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Affiliation(s)
- P Vogel
- Pathology Department, Lexicon Pharmaceuticals Inc., 8800 Technology Forest Place, The Woodlands, TX 77381, USA.
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15
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Flow on the right side of the gastrocoel roof plate is dispensable for symmetry breakage in the frog Xenopus laevis. Dev Biol 2009; 331:281-91. [PMID: 19450574 DOI: 10.1016/j.ydbio.2009.05.547] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2008] [Revised: 05/08/2009] [Accepted: 05/11/2009] [Indexed: 02/04/2023]
Abstract
Leftward flow of extracellular fluid breaks the bilateral symmetry of most vertebrate embryos, manifested by the ensuing asymmetric induction of Nodal signaling in the left lateral plate mesoderm (LPM). Flow is generated by rotational beating of polarized monocilia at the posterior notochord (PNC; mammals), Kupffer's vesicle (KV; teleost fish) and the gastrocoel roof plate (GRP; amphibians). To manipulate flow in a defined way we cloned dynein heavy chain genes dnah5, 9 and 11 in Xenopus. dnah9 expression was closely related to motile cilia from neurulation onwards. Morphant tadpoles showed impaired epidermal ciliary beating. Leftward flow at the GRP was absent, resulting in embryos with loss of asymmetric marker gene expression. Remarkably, unilateral knockdown on the right side of the GRP did not affect laterality, while left-sided ablation of flow abolished marker gene expression. Thus, flow was required exclusively on the left side of the GRP to break symmetry in the frog. Our data suggest that the substrate of flow is generated within the GRP and not at its margin, disqualifying Nodal as a candidate morphogen.
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16
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Cartwright JH, Piro O, Tuval I. Fluid dynamics in developmental biology: moving fluids that shape ontogeny. HFSP JOURNAL 2008; 3:77-93. [PMID: 19794816 PMCID: PMC2707792 DOI: 10.2976/1.3043738] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2008] [Accepted: 10/31/2008] [Indexed: 12/19/2022]
Abstract
Human conception, indeed fertilization in general, takes place in a fluid, but what role does fluid dynamics have during the subsequent development of an organism? It is becoming increasingly clear that the number of genes in the genome of a typical organism is not sufficient to specify the minutiae of all features of its ontogeny. Instead, genetics often acts as a choreographer, guiding development but leaving some aspects to be controlled by physical and chemical means. Fluids are ubiquitous in biological systems, so it is not surprising that fluid dynamics should play an important role in the physical and chemical processes shaping ontogeny. However, only in a few cases have the strands been teased apart to see exactly how fluid forces operate to guide development. Here, we review instances in which the hand of fluid dynamics in developmental biology is acknowledged, both in human development and within a wider biological context, together with some in which fluid dynamics is notable but whose workings have yet to be understood, and we provide a fluid dynamicist's perspective on possible avenues for future research.
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Affiliation(s)
- Julyan H.E. Cartwright
- Instituto Andaluz de Ciencias de la Tierra, CSIC-Universidad de Granada, Campus Fuentenueva, E-18071 Granada, Spain
| | - Oreste Piro
- Departamento de Física e Instituto de Física Interdisciplinar y Sistemas Complejos IFISC (CSIC-UIB), Universitat de les Illes Balears, E-07122 Palma de Mallorca, Spain
| | - Idan Tuval
- Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge CB3 0WA, United Kingdom
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