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Literature on cilia

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Structure and function of mammalian cilia, Peter Satir et al. (2008) Title Structure and function of mammalian cilia Authors Peter Satir, Søren Christensen Publication Histochemistry and Cell Biology Volume 129 Issue 6 Pages 687-693 Date June 16, 2008 Abstract In the past half century, beginning with electron microscopic studies of 9 + 2 motile and 9 + 0 primary cilia, novel insights have been obtained regarding the structure and function of mammalian cilia. All cilia can now be viewed as sensory cellular antennae that coordinate a large number of cellular signaling pathways, sometimes coupling the signaling to ciliary motility or alternatively to cell division and differentiation. This view has had unanticipated consequences for our understanding of developmental processes and human disease. DOI 10.1007/s00418-008-0416-9 An Integrative Computational Model of Multiciliary Beating, Xingzhou Yang et al. (2008) Title An Integrative Computational Model of Multiciliary Beating Authors Xingzhou Yang, Robert Dillon, Lisa Fauci Publication Bulletin of Mathematical Biology Volume 70 Issue 4 Pages 1192-1215 Date May 04, 2008 Abstract The coordinated beating of motile cilia is responsible for ovum transport in the oviduct, transport of mucus in the respiratory tract, and is the basis of motility in many single-celled organisms. The beating of a single motile cilium is achieved by the ATP-driven activation cycles of thousands of dynein molecular motors that cause neighboring microtubule doublets within the ciliary axoneme to slide relative to each other. The precise nature of the spatial and temporal coordination of these individual motors is still not completely understood. The emergent geometry and dynamics of ciliary beating is a consequence of the coupling of these internal force-generating motors, the passive elastic properties of the axonemal structure, and the external viscous, incompressible fluid. Here, we extend our integrative model of a single cilium that couples internal force generation with the surrounding fluid to the investigation of multiciliary interaction. This computational model allows us to predict the geometry of beating, along with the detailed description of the time-dependent flow field both near and away from the cilia. We show that synchrony and metachrony can, indeed, arise from hydrodynamic coupling. We also investigate the effects of viscosity and neighboring cilia on ciliary beat frequency. Moreover, since we have precise flow information, we also measure the dependence of the total flow pumped per cilium per beat upon parameters such as viscosity and ciliary spacing. DOI 10.1007/s11538-008-9296-3 Bio-inspired electric cilia development for biomedical applications: use of ionic electro-active polymer, nanowire arrays, and micro-stereo-lithography, Hargsoon Yoon et al. (2007) Title Bio-inspired electric cilia development for biomedical applications: use of ionic electro-active polymer, nanowire arrays, and micro-stereo-lithography Authors Hargsoon Yoon, Vasuda Ramachandran, Devesh C. Deshpande, Vijay K. Varadan Volume 6528 Pages 652804-9 Date April 06, 2007 Proceedings Title Nanosensors, Microsensors, and Biosensors and Systems 2007 Conference Name Nanosensors, Microsensors, and Biosensors and Systems 2007 Place San Diego, California, USA Publisher SPIE DOI 10.1117/12.717660 URL http://link.aip.org/link/?PSI/6528/652804/1 Active micromixer based on artificial cilia, Vinayak V. Khatavkar et al. (2007) Title Active micromixer based on artificial cilia Authors Vinayak V. Khatavkar, Patrick D. Anderson, Jaap M. J. den Toonder, Han E. H. Meijer Publication Physics of Fluids Volume 19 Issue 8 Pages 083605-13 Date 2007 Abstract We propose a design for an active micromixer that is inspired by the motion of ciliated micro-organisms occurring in nature. The conceptual design consists of an array of individually addressable artificial cilia in the form of microactuators covering the channel wall. The microactuators can be set into motion by an external stimulus such as an electric or a magnetic field, inducing either a primary or secondary motion in the surrounding fluid. To validate the concept and to help to design the precise mixer configuration, we developed a computational fluid-structure model. This model is based on a fictitious domain method that couples the microactuator motion to the concomitant fluid flow, fully capturing the mutual fluid-structure interactions. The simulated flow patterns resulting from the motion of single and multiple actuated elements (in a microchannel filled with a Newtonian fluid) under the action of a time-periodic forcing function are analyzed using dynamical systems theory to quantify the mixing efficiency. The results show that with a proper actuation scheme, two microactuators placed on the same wall of a microchannel can indeed induce effective mixing by chaotic advection; their distance should be small, but collisions should be avoided, and they can be actuated in a rather broad regime around 90° out of phase. Placing actuators on opposite walls also induces exponential stretching in the fluid, but if their length is relatively small, of the order of 20% of the channel height, mixing effectiveness is higher when they are arranged on the same wall DOI 10.1063/1.2762206 URL http://www.mate.tue.nl/mate/showabstract.php/8113 Mechanical Properties and Consequences of Stereocilia and Extracellular Links in Vestibular Hair Bundles, Jong-Hoon Nam et al. (2006) Title Mechanical Properties and Consequences of Stereocilia and Extracellular Links in Vestibular Hair Bundles Authors Jong-Hoon Nam, John R. Cotton, Ellengene H. Peterson, Wally Grant Publication Biophysical Journal Volume 90 Issue 8 Pages 2786-2795 Date April 15, 2006 Abstract Although knowledge of the fine structure of vestibular hair bundles is increasing, the mechanical properties and functional significance of those structures remain unclear. In 2004, Bashtanov and colleagues reported the contribution of different extracellular links to bundle stiffness. We simulated Bashtanov's experimental protocol using a three-dimensional finite element bundle model with geometry measured from a typical striolar hair cell. Unlike any previous models, we separately consider two types of horizontal links: shaft links and upper lateral links. Our most important results are as follows. First, we identified the material properties required to match Bashtanov's experiment: stereocilia Young's modulus of 0.74 GPa, tip link assembly (gating spring) stiffness of 5300 pN/microm, and the combined stiffness of shaft links binding two adjacent stereocilia of 750 [~] 2250 pN/microm. Second, we conclude that upper lateral links are likely to have nonlinear mechanical properties: they have minimal stiffness during small bundle deformations but stiffen as the bundle deflects further. Third, we estimated the stiffness of the gating spring based on our realistic three-dimensional bundle model rather than a conventional model relying on the parallel arrangement assumption. Our predicted stiffness of the gating spring was greater than the previous estimation. DOI 10.1529/biophysj.105.066027 URL http://www.biophysj.org/cgi/content/abstract/90/8/2786 The importance of being cilia, David Brinley (2005) Title The importance of being cilia Author David Brinley Publication HHMI Bulletin Volume 18 Issue 2 Pages 32-36,64 Date September 2005 Abstract On the surface of nearly every cell in the body is a slender protuberance called the primary cilium. Although ubiquitous, the primary cilium was long considered—with a few exceptions—to be a largely useless evolutionary vestige, destined to go the way of the tailbone and the wisdom tooth. But now we know that cilia are functioning organelles, essential to normal development and health. URL http://www.hhmi.org/bulletin/sept2005/features/cilia.html Primary cilia: new perspectives, Denys Wheatley (2004) Title Primary cilia: new perspectives Author Denys Wheatley Publication Cell Biology International Volume 28 Issue 2 Pages 75-77 Date 2004 DOI 10.1016/j.cellbi.2003.11.005 URL http://www.sciencedirect.com/science/article/B6WCB-4BRTK1K-2/1/b9e36fe2cc424fa3a6d636f3d41b15f8 Mechanosensory Transduction in "Sensory" and "Motile" Cilia, Michael L. Wiederhold (2003) Title Mechanosensory Transduction in "Sensory" and "Motile" Cilia Author Michael L. Wiederhold Publication Annual Review of Biophysics and Bioengineering Volume 5 Pages 39-62 Date 2003-11-28 DOI 10.1146/annurev.bb.05.060176.000351 URL http://arjournals.annualreviews.org/doi/abs/10.1146/annurev.bb.05.060176.000351 Mechanics of Motor Proteins and the Cytoskeleton, J Howard (2002) Title Mechanics of Motor Proteins and the Cytoskeleton Author J Howard Publication Applied Mechanics Reviews Volume 55 Issue 2 Pages B39 Date March, 2002 DOI 10.1115/1.1451234 URL http://link.aip.org/link/?AMR/55/B39/2 The Speed of a Protozoan, Ross Krupnik (2000) Title The Speed of a Protozoan Author Ross Krupnik Date 2000 Abstract The Physics Factbook™ is an encyclopedia of scientific essays written by high school students that can be used by anybody. It is an exercise in library research methods in which students are sent out in search of a measurement with the intent of having them find more than just a number with a unit. It is an ongoing project with no foreseeable end date or limits. URL http://hypertextbook.com/facts/2000/RossKrupnik.shtml Cilia and Flagella: Structure and Movement (Chapter 19.4), Harvey Lodish et al. (2000) Title Cilia and Flagella: Structure and Movement (Chapter 19.4) Authors Harvey Lodish, Arnold Berk, Lawrence S. Zipursky, Paul Matsudaira, David Baltimore, James Darnell Date 2000 Place New York Publisher W.H. Freeman and Company URL http://www.ncbi.nlm.nih.gov/books/bv.fcgi?rid=mcb Flexural Rigidity of Echinoderm Sperm Flagella, Sumio Ishijima et al. (1994) Title Flexural Rigidity of Echinoderm Sperm Flagella Authors Sumio Ishijima, Yukio Hiramoto Publication Cell Structure and Function Volume 19 Issue 6 Pages 349-362 Date 1994/05/31 Abstract The stiffness (flexural rigidity) of live sperm flagella, Triton-demembranated flagella (axonernes), trypsin-digested axonemes, and doublet microtubules of the axonemes in echinoderms was determined from the relationship between their deformation when a stream of medium was applied and the viscous resistance of the medium acting on the flagellum. The stiffness of the flagellum beating in seawater was 5.8×10-21 Nm2 for bending in the direction perpendicular to the beating plane and 4.2×10-22 Nm2 for bending within the beating plane. A similar difference in stiffness from the difference in bending directions was found in reactivated flagella with 1 Mm ATP. The stiffness of live flagella immobilized in CO2-saturated seawater and axonemes in ATP-free medium was similar to that of beating flagella for bending in the direction perpendicular to the beating plane. The stiffness of motionless flagella significantly decreased with erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA) and vanadate. The trypsin-digestion of motionless axonemes did not change their stiffness. The stiffness of doublet microtubules was 1.4 ×10-23 Nm2 in 0.1 mM ATP medium and 6.1×10-23 Nm2 in ATP-free medium. These results suggest that doublet pairs lying parallel to the beating plane of the flagellum retain fewer cross-bridges than doublet pairs lying perpendicular to the beating palne. URL http://www.journalarchive.jst.go.jp/english/jnlabstract_en.php?cdjournal=csf1975&cdvol=19&noissue=6 Stiffness of sensory-cell hair bundles in the isolated guinea pig cochlea, David Strelioff et al. (1984) Title Stiffness of sensory-cell hair bundles in the isolated guinea pig cochlea Authors David Strelioff, Åke Flock Publication Hearing Research Volume 15 Issue 1 Pages 19-28 Date July 1984 Abstract Stiffness of hair bundles on cochlear hair cells was measured in turns 2, 3 and 4 of isolated preparations of the guinea-pig organ of Corti maintained in tissue culture medium. Defined as the force required to produce a linear 1.0 [mu]m deflection of the hair-bundle tip, stiffness is greater for deflection in the excitatory than in the inhibitory direction. The excitatory-to-inhibitory ratio for inner hair cells (IHC) is significantly lower than the ratio for outer hair cells (OHC). Hair-bundle stiffness decreases radially from the first to third rows of OHC. Over the measurement range of 9.0-18.0 mm from the stapes hair-bundle stiffness decreases much more for OHC (88-97%) than for IHC (50%). Although an increase in hair-bundle length with distance from the stapes accounts for some of the observed stiffness decrease, the major decrease is due to an increase in compliance of the sensory-hair attachment to the hair-cell surface. DOI 10.1016/0378-5955(84)90221-1 URL http://www.sciencedirect.com/science/article/B6T73-480TS79-4/1/6d532fe6e5b6b2858c00bc1117cab60f Direct Measurements of the Stiffness of Echinoderm Sperm Flagella, Makato Okuno et al. (1979) Title Direct Measurements of the Stiffness of Echinoderm Sperm Flagella Authors Makato Okuno, Yukio Hiramoto Publication Journal of Experimental Biology Volume 79 Issue 1 Pages 235-243 Date April 1, 1979 Abstract 1. The stiffness (flexural rigidity) of some echinoderm sperm flagella was measured, using a flexible glass microneedle.2. Values of 0.3-1.5 x 10-21 N m2 were obtained for the stiffness of live flagella which were immobilized with CO2-saturated sea water.3. The immobilized live flagellum was uniform in stiffness along its entire length, except in a particular plane of imposed bending in which flexible regions were observed.4. Demembranated flagella (Hemicentrotus pulcherrimus) in an ATP-free solution were about ten times stiffer (1.1 x 10-20 N m2) than immobilized live ones (0.5-0.9 x 10-21 N m2). The stiffness was decreased by addition of ATP to the solution and became equivalent to that of live ones when the solution contained 10 mM ATP.5. In the demembranated flagella, the effects of ADP and ATP on the stiffness were similar. Other nucleotide phosphates and inorganic phosphate did not reduce the stiffness.6. Young's modulus of microtubules is estimated to be 2.5 x 109 Nm2 on the basis that the microtubules have no tight connexion with one another in immobilized live flagella. URL http://jeb.biologists.org/cgi/content/abstract/79/1/235 Fluid transport by cilia between parallel plates, N. Liron (1977) Title Fluid transport by cilia between parallel plates Author N. Liron Publication Journal of Fluid Mechanics Volume 86 Issue 04 Pages 705-726 Date September 8 1977 Abstract The problem of fluid transport by cilia is investigated using the Green's function for a Stokeslet between two parallel plates. The discrete-cilia approach is used in building the model, and a readily usable expression for the velocities is obtained. Dependence on the direction of the metachronal wave and on time is not averaged out. Velocity fields, pressure fields and fluxes due to a single Stokeslet and to an infinite line of Stokeslets are discussed. It is found that the flux associated with Stokeslets in between two parallel plates is always zero, in contrast to a Stokeslet parallel to, and above, one plate. In the model one also has to add a plane Poiseuille flow, which incorporates non-zero flux. The flow due to the Stokeslet solution imposes a positive pressure gradient downstream, and the Poiseuille flow a negative pressure gradient. Calculated velocity profiles, in the pumping range, are seen to be time-independent in the centre of the channel and vary between a negative parabolic profile and a plug flow. The reason for these profiles and some possible biological applications are discussed. DOI 10.1017/S0022112078001354 Fluid Mechanics of Propulsion by Cilia and Flagella, C. Brennen et al. (1977) Title Fluid Mechanics of Propulsion by Cilia and Flagella Authors C. Brennen, H. Winet Publication Annual Review of Fluid Mechanics Volume 9 Issue 1 Pages 339-398 Date 1977 DOI 10.1146/annurev.fl.09.010177.002011 URL http://arjournals.annualreviews.org/doi/abs/10.1146/annurev.fl.09.010177.002011 The distribution, activity, and function of the cilia in the frog brain, Deborah J. Nelson et al. (1974) Title The distribution, activity, and function of the cilia in the frog brain Authors Deborah J. Nelson, Ernest M. Wright Publication J Physiol Volume 243 Issue 1 Pages 63-78 Date November 1, 1974 Abstract 1. The distribution, activity, and function of the cilia in the brain was studied using in vitro preparations of the frog choroid plexuses and ependyma. 2. Scanning electron microscopy revealed that twenty to forty cilia, about 20 microm long, project from the cells of the choroidal epithelium and ependyma into the ventricular system of the brain. 3. These cilia beat at a constant frequency which ranged from 5 to 20 c/s. Ciliary activity was enhanced by ATP, cyclic AMP, theophylline, and acetylcholine, and was depressed by DNP, IAA, Ni2+, La3+, and Co2+. 4. Ciliary motion produced a flow of c.s.f. over the surface of the cells lining the ventricles, and in the choroid plexus this flow reduced the effective thickness of the unstirred layer adjacent to the epithelium by about 100 microm. 5. These results are discussed in relation to the factors that control the frequency of ciliary beating, and the role of the cilia in the circulation of the c.s.f. URL http://jp.physoc.org/cgi/content/abstract/243/1/63 Flexural Rigidity and Elastic Constant of Cilia, Shoji A. Baba (1972) Title Flexural Rigidity and Elastic Constant of Cilia Author Shoji A. Baba Publication Journal of Experimental Biology Volume 56 Issue 2 Pages 459-467 Date April 1, 1972 Abstract 1. The flexural rigidity of the large abfrontal cilia of Mytilus has been measured with a flexible glass micro-needle.2. The same cilium has similar values to the flexural rigidity irrespective of the phases of beat cycle (including the recovery phase) and of the direction of force applied.3. The values of 3-13 x 10-9 dyne. cm2 have been obtained for the flexural rigidity of compound cilia of various sizes; 2-3 x 10-10 dyne.cm2 for that of the component cilia.4. The Young's modulus of the microtubule is estimated to be 5-9 x 1010 dyne/cm2 on the basis that the outer doublet microtubules are tightly connected with one another. URL http://jeb.biologists.org/cgi/content/abstract/56/2/459 Elastic Properties of the Sea Urchin Sperm Flagellum, Robert Rikmenspoel (1966) Title Elastic Properties of the Sea Urchin Sperm Flagellum Author Robert Rikmenspoel Publication Biophysical Journal Volume 6 Issue 4 Pages 471-479 Date July 1, 1966 Abstract The theory of flexural vibrations in thin rods, applied to the movement of flagella, has been extended to include an investigation of the influence of the boundary conditions on the theoretical waveforms. It was found that for flagella which are flexible enough, the flexibility can be estimated solely from the wavelength of the wave traveling in it. This can be expected to hold for those flagella which do not possess a fibrous sheath. The bending moment in flagella in which the ampitude of the wave is maintained as the wave travels distally is almost completely produced by active contractile elements. This means that the active bending moment can be estimated from the radius of curvature of the flagellum and the stiffness. The above findings were applied to the case of the sea urchin sperm flagellum. One finds that the stiffness of the flagellum is caused mainly by the nine longitudinal fibers which must have a Young's modulus of slightly less than 108dyne/cm2. The longitudinal fibers need to develop a tension of 1.6 x 108dyne/cm2 to account for the bending moment in the flagellum. These two figures are in line with those found for muscle fibers. URL http://www.biophysj.org/cgi/content/abstract/6/4/471

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