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  • Life and Medical Sciences  (30,791)
  • Wiley-Blackwell  (30,791)
  • 1
    Electronic Resource
    Electronic Resource
    Regulation of calcium distribution in bovine sperm cells: Cytochemical evidence for motility control mechanisms (1982)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982), S. 225-242 
    Details
    ISSN: 0886-1544
    Keywords: spermatozoa ; calcium ion transport ; motility regulation ; cholinergic agonists ; ouabain ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Behavioral responses of mature spermatozoa treated with neurotropic factors suggest that calcium entry and intracellular transport may be regulated by a cholinergic mediated program. To test the validity of this proposed mechanism, the effect of several agents on Ca distribution in the sperm cell was examined cytochemically.Sites of Ca accumulation were visualized in thin sections of bull spermatozoa by the application of a modification of Gomori's histochemical procedure for phosphatases. Intact bull sperm cells incubated at room temperature in a buffered balanced salt solution containing 5 mM/liter of CaCl2 showed small, randomly scattered deposits of the reaction product. Similarly treated sperm cells, plasmolyzed in hypoosmotic KCl, revealed a greatly increased amount of deposit associated with the cell membranes (mitochondrial surfaces and plasmalemma), the axonemal complex components, and satellite fibers adjacent to the outer dense fibers. Preincubation of intact cells in nicotine or eserine considerably enhanced the entry of calcium into the cell and its association with the membranes and other intracellular organelles. Decamethonium, an irreversible depolarizer and blocker of cholinergic receptors, interfered with the uptake and intracellular distribution of the calcium. Ouabain, the digitalis glycoside that decreases progressive motility of bull sperm and inhibits Na-, K-ATPase, appears to block Ca efflux, causing an intense accumulation of electron-opaque particles in the plasma membrane while smaller numbers of particles are distributed sparsely throughout the cell interior.The cytochemical results showing enhanced calcium entry in the presence of cholinergic agents, depressed intracellular calcium in cells treated with cholinergic receptor blocker, and intense accumulation of calcium within the cell membrane in the presence of ouabain are consistent with spermatozoan behavioral responses to these agents. These observations support the concept that neurotropic factors may be involved in regulating transmembrane and intracellular transport of ions in control of sperm cell function.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970020304
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  • 2
    Electronic Resource
    Electronic Resource
    Persistence of the expression of β-tropomyosin in dystrophic avian pectoral muscle (1982)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982), S. 309-315 
    Details
    ISSN: 0886-1544
    Keywords: tropomyosin ; avian muscular dystrophy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The isotype pattern of tropomyosin was investigated in normal and dystrophic avian pectroal muscle using two-dimensional gel electrophoresis. Previous reports have shown that adult pectoral muscle of chickens contains only the α-subunit of tropomyosin and a breast-type troponin-T (TN-T), whereas pectoral fetal muscle contains both α- and β-tropomyosin and leg-type TN-T. The change from the fetal to the adult forms begins shortly after hatching. It has been previously reported that avian dystrophic pectoral muscle contains both the leg- and breast-type TN-T; we show that in avian dystrophic muscle there is also persistent expression of the β-subunit of tropomyosin.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970020309
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  • 3
    Electronic Resource
    Electronic Resource
    Masthead (1982)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970020401
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  • 4
    Electronic Resource
    Electronic Resource
    A calcium- and pH-regulated actin binding protein from D. discoideum (1982)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982), S. 287-308 
    Details
    ISSN: 0886-1544
    Keywords: actin-binding protein ; Dictyostelium ; cytoskeleton ; amoeboid movement ; calcium ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A protein from Dictyostelium discoideum with an apparent subunit molecular weight of 95,000 daltons (95K protein) was previously identified as an actin-binding protein ‘Hellewell and Taylor, 1979’. In this paper, we present a method for purifying the protein, and characterize some important aspects of its structure and function. Purification of the 95K protein is achieved by fractionation with ammonium sulfate followed by chromatography on DEAE-cellulose, gel filtration on 6% agarose, and final purification on hydroxyapatite. The 95K protein is a dimer, composed of apparently identical subunits. It is a rod-shaped molecule, 38 nm in length, with a Stokes radius of 74 Å. In these structural properties, the 95K protein is similar to muscle and nonmuscle α-actinins. The 95K protein and filamin are equally competent, when compared on a weight basis, to enhance the apparent viscosity of actin as determined by falling ball viscometry. The apparent viscosity of mixtures of the 95K protein and actin is dramatically reduced at pH greater than 7.0 or free ‘Ca2+’ greater than 10-7 M. We also examine the mechanism by which calcium regulates the interaction of the 95K protein and actin. A change in free ‘Ca2+’ induces no detectable change in the quaternary structure of the 95K protein. Our experiments indicate that the 95K protein does not dramatically alter the length distribution of actin filaments in the presence of micromolar free ‘Ca2+’. A large fraction of the 95K protein cosediments with actin in the presence of low free ‘Ca2+’ (ca. 3 × 10-8M), but not in the presence of high free ‘Ca2+’ (ca. 4 × 10-6M). We conclude that increased free ‘Ca2+’ inhibits gelation of actin by the 95K protein by reducing the affinity of the 95K protein for actin. We propose that 95K protein is an important component of the cytoskeletal/contractile system in D. discoideum amoebae.
    Additional Material: 14 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970020308
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  • 5
    Electronic Resource
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    In situ demonstration of actin in normal and injured ocular tissues using 7-nitrobenz-2-oxa-1,3-diazole phallacidin (1982)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982), S. 343-354 
    Details
    ISSN: 0886-1544
    Keywords: NBD-phallacidin ; actin ; ocular tissues ; wound repair ; stress fibers ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The fluorescent derivative of the actin-binding toxin phallacidin, 7-nitrobenz-2-oxa-1,3 diazole phallacidin, has been used to cytologically demonstrate the presence of actin in lens epithelium, corneal endothelium, and retinal pigment epithelium. In these noninjured tissues, no stress fibers are observed and fluorescence is confined mainly to an area at or near the cell membrane, although some diffuse cytoplasmic staining can also be seen. However, following injury to either the lens epithelium or corneal endothelium of rats and frogs, stress fibers are detected, but only in those cells that migrate into the wound area. Cells on the periphery of each tissue do not partake in would repair and thus maintain their normal appearance. After the tissue has regenerated, stress fibers disappear, and those cells involved in the injury response return to their normal morphology.When rabbit corneal endothelium is placed in tissue culture, stress fibers are observed as the cells migrate away from the initial explant. Upon reaching confluency, these cells spread out and each is surrounded by thick actin-containing bands. Furthermore, they exhibit some stress cables within their cytoplasm. This is in contrast to their appearance in vivo where stress fibers are absent and fluorescence is limited to a region near the cell membrane.
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970020404
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  • 6
    Electronic Resource
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    Motility of the 6 + 0 flagellum of lecudina tuzetae (1982)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982), S. 369-383 
    Details
    ISSN: 0886-1544
    Keywords: motility ; flagella ; cilia ; microtubules ; Gregarines ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The male gametes of the parasitic protozoan, Lecudina tuzetae, have a motile flagellum with a “6 + O” ultrastructure ‘Schrével and Besse, 1975’. These gametes were isolated from the cysts in which they develop and were observed and photographed under a variety of conditions. The flagella beat continuously, without stopping and starting, with a beat period of about 2 sec. They can beat in solutions whose viscosities are greater than 0.5 Nsm-2 (l Nsm-2 = 103 cP). The waveform can be approximated by a series of helical arcs and interconnecting straight regions that travel from the base to the tip. The helical regions have a radius of curvature of 3.2 μm and subtend a final angle of 1.7 radians. The straight portions are 2.0 μm in length. There are two sets of opposing bends, but they do not originate in the same plane. The resulting waveform is an approximately helical coil, with a pitch of 9.8 μm, a pitch angle of 0.6 radian and a peak-to-peak amplitude of 2.3 μm. The sense of the coil is left handed. The axoneme twists during beating. The main differences between the movement of this flagellum and that of typical 9 + 2 flagella are a low beat frequency and three-dimensional bends that produce relatively little forward movement of the cell. Twisting is discussed as a means of discriminating between some types of models of flagellar motility.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970020406
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  • 7
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    Binding stoichiometry of 21S dynein to A and B subfiber microtubules (1982)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982), S. 429-443 
    Details
    ISSN: 0886-1544
    Keywords: 21S dynein ; tubulin ; binding stoichiometry ; ATP sensitivity ; binding cooperativity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The binding properties of Tetrahymena 21S dynein to doublet A and B subfiber microtubules were analyzed by both a turbidimetric assay (Δ A350 nm) and electron microscopy. KCl-extracted, sucrose-gradient, purified 21S dynein binds to each of the two kinds of axonemal microtubules in both ATP-insensitive and ATP-sensitive modes, even though only a single type of binding occurs to each of the subfibers in situ. Total dynein bound to axonemal microtubules is a composite of binding that is sensitive to dissociation by ATP and binding that is insensitive to ATP. Each exhibits a different binding profile. Total binding exhibits a sigmoid profile (h = 1.93) and saturates at 1.49 mg D/mg T. ATP-sensitive binding likewise exhibits a sigmoid profile (h = 2.66) but saturates at 1.06 mg D/mg T. Binding occurs with a similar affinity for both A and B subfibers. The Hill coefficient (h) for ATP-sensitive binding implies positive cooperativity between binding events. ATP-insensitive binding was studied independently in 20 μM ATP, 10 μM vanadate, which blocks ATP-sensitive binding. ATP-insensitive binding exhibits a hyperbolic profile (h = 1.0) and likewise occurs along each of the two kinds of axonemal tubules. Binding saturates at 0.87 mg D/mg T. The binding data suggest that the tubulin dimer has conserved both ATP-sensitive and ATP-insensitive binding sites for 21S dynein, even though the sites may not be expressed in vivo.
    Additional Material: 6 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970020503
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  • 8
    Electronic Resource
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    Videodisc Supplement. Announcement (1982)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982), S. i 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970020602
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  • 9
    Electronic Resource
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    Microtubule capping structures at the tips of tracheal cilia: Evidence for their firm attachment during ciliary bend formation and the restriction of microtubule sliding (1982)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982), S. 549-572 
    Details
    ISSN: 0886-1544
    Keywords: flagella ; cilia ; trachea ; microtubules ; crowns ; microtubule assembly ; caps ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The distal tips of the central pair and A-microtubules are capped in mammalian and avian tracheal cilia. The capping structures are similar to those found in protozoan cilia and flagella [Dentler, 1981], and consist of a central microtubule cap that links the central microtubules to the membrane or to the ciliary crown and A-microtubule plugs that insert into the lumen of each of the A-microtubule plugs is bound to the central microtubule cap by distal filaments. The ends of the central and outer doublet microtubules are tightly bound to the cap in both intact and in demembranated and reactivated tracheal cilia. Analysis of the displacement of the microtubule tips in cilia fixed at various bend angles revealed that the displacements of A-microtubules are only partially in agreement with those predicted by the sliding filament model [Satir, 1968]. These results are discussed with respect to the regulation of microtubule sliding in capped cilia and the role of the microtubule capping structures in microtubule assembly.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970020605
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  • 10
    Electronic Resource
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    Movement and coordination of tracheal cilia and the relation of these to mucus transport (1982)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982), S. 19-24 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 1 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970020706
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  • 11
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    The identification and localization of actin and actin-like filaments in lactating guinea pig mammary gland alveolar cells (1981)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 1 (1981), S. 329-347 
    Details
    ISSN: 0886-1544
    Keywords: actin ; microfilaments ; heavy meromyosin ; mammary gland ; secretion ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cytochalasin B, a microfilament-altering drug, inhibits lactose synthesis in lactating guinea pig mammary gland [Biochim. Biophys. Acta 392:20, 1975] but not primarily by inhibiting glucose transport [Eur. J. Cell Biol. 20:150, 1979]. In order to study the possible role of microfilaments in lactose synthesis and secretion, we isolated both the alveolar (milk-secreting) and myoepithelial (contractile) cells from lactating mammary gland. Light microscopy shows that the alveolar cell fraction (viability approximately 71%) is homogenous and that the cells retain strong polarity of secretory structures in the apical region. Two proteins were extracted from the alveolar cell fraction. One (mol wt 42,000) comigrates with skeletal muscle actin on SDS-PAGE gels. The other, a high-molecular-weight (180,000) protein (HMWP) may be analogous to actin-binding protein or clathrin. An extract from the myoepithelial cell fraction also contains a protein that comigrates with actin but no HMWP. Whole tissue extract contains the 42K protein, and a 185K HMWP. Examination of the alveolar cell extract by electron microscopic (EM) negative staining revealed meshworks of multistranded, interconnecting filaments, with attached globular structures (100-200 A) (possibly the HMWP) and single filaments (40-60 A diameter) branching off. To localize these filamentous structures in situ, whole tissue was glycerinated and incubated with rabbit skeletal muscle heavy meromyosin (HMM). Masses of filaments in myoepithelial cells served as convenient standards for HMM decoration. Decorated filaments have cross-arms or projections, unlike the narrow, smooth filaments of control tissue. Decorated filaments in alveolar cells are located beneath the plasma membrane, in close association with secretory vacuoles, and near the Golgi apparatus; filaments near the latter two are often oriented perpendicular to the plasma membrane. Microvesicles are embedded in meshworks under the plasmalemma and near the Golgi apparatus. Intermediate-sized (85-115 A diameter), non-decorated filaments diverge from the meshworks of decorated filaments. Microvesicles are associated with intermediate-sized filaments as well. The association of actin-like filaments with secretory vacuoles and microvesicles and their location in areas of the cell concerned with biosynthetic activities suggest a possible function in the intracellular transport of secretory products.
    Additional Material: 13 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970010305
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  • 12
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    Motility of 9 + 0 mutants of Chlamydomonas rheinhardtii (1982)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982), S. 165-168 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970020731
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  • 13
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    Role of calmodulin in the flagellar axoneme: Effect of phenothiazines on reactivated axonemes of Chlamydomonas (1982)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982), S. 199-204 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 4 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970020738
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  • 14
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    Serum complement (C'3a and C'5)-induced inhibition of rabbit tracheal cilia (1982)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982), S. 71-75 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 3 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970020715
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  • 15
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    Invited review: Bacterial flagellar sheaths: Structures in search of a function (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 93-103 
    Details
    ISSN: 0886-1544
    Keywords: bacterial motility ; flagella ; sheathed flagella ; complex flagella ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Although bacterial flagellar sheaths were observed over 30 years ago, they may still be characterized as structures in search of a function. In addition to true sheaths, bacterial flagella may possess other adornments that cause an increase in the organelle's cross-sectional diameter. These “complex flagella” are sharply differentiated from sheathed flagella. Immunological and chemical distinctions have been found between flagellar sheaths, flagellar cores, and LPS layers inferred to be the sheath sensu stricto. Although complex flagella may serve as specific receptors for flagellotropic phages or in allowing for more efficient swimming in viscous environments, similar functions have not yet been attributed to true sheaths. It is postulated that flagellar sheaths may allow for specific interaction between a bacterium and a surface. In addition, there is a problem as to the relationship between a rapidly rotating flagellum and the sheath.
    Additional Material: 2 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970030108
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  • 16
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    Coelomocyte motility (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 113-121 
    Details
    ISSN: 0886-1544
    Keywords: coelomocytes ; filopodia ; whole cell translocation ; video microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have utilized a video-enhanced contrast system coupled to a DIC-equipped microscope to examine the motility of both whole coelomocytes and individual filopodia. When the cells are left in diluted coelomic fluid, they exhibit a fibroblast-like mode of translocation across the substrate. These cells extend lamellipodia at their advancing margin and develop retraction fibers at the trailing edge. Filopodia are actively extended from the lamellipodia of the advancing margin. Cells that are washed free of the coelomic fluid and placed in an isotonic buffer lose their ability to translocate. Filopodia on these stationary cells are seen to undergo a series of waving and bending motions. These motions are rapid and result in a filopodium folding back upon itself only to reextend later. Both forms of motility are discussed in light of the existing structural and biochemical knowledge of this and other cell types.
    Additional Material: 11 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970030202
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  • 17
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    Quantitative studies on polarization optical properties of living cells III: Cortical birefringence of the dividing sea urchin egg (1981)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 1 (1981), S. 387-397 
    Details
    ISSN: 0886-1544
    Keywords: birefringence ; polarizing microscope ; sea urchin egg ; cortex ; mitosis ; cleavage ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Birefringence (BR) at the cell surface of fertilized eggs of the sand-dollar, Clypeaster japonicus, during mitosis and cleavage was determined with a photoelectric BR detection apparatus [Hiramoto et al, 1981a]. The cortex of about 2 μm thickness is birefringent positive with respect to the normal to the cell surface. The hyaline layer is negatively birefringent. The halo-layer consisting of a row of microvilli surrounding the egg is positively birefringent in normal Ca-free sea water, while it is negatively birefringent in Ca-free sea water with high refractive index. The BR of the cortex gradually increases over the entire surface during mitosis until the onset of cleavage. The BR of the cortex at the polar region reaches a maximum shortly after the onset of cleavage and then decreases, while the BR of the cortex at the equatorial region begins to decrease shortly before the onset of cleavage, reaches a minimum shortly after the cleavage starts, and then increases again as the cleavage furrow advances. The coefficient of birefringence of the cortex is about 2.5 × 10-5 at the maximum. The BR change of the cortex during mitosis and cleavage is interpreted as a passive deformation caused by the constriction of the contractile ring as well as an active structural change of the cortex occurring in the dividing cell.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970010309
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  • 18
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    Microtubule-containing detergent-extracted cytoskeletons in sea urchin eggs from fertilization through cell division: Antitubulin immunofluorescence microscopy (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 213-226 
    Details
    ISSN: 0886-1544
    Keywords: microtubules ; fertilization ; cell division ; sea urchin ; cytoskeleton ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The microtubule-containing structures that appear in eggs during fertilization and cell division in the sea urchins Lytechinus variegatus and Arbacia punctulata were detected by antitubulin immunofluorescence microscopy of detergent extracted cytoskeletal preparations. The extraction buffer, which is composed of 0.55 mM MgCl2, 10 mM EGTA, 25 mM MES, 25% glycerol, 1% Nonidet P-40, and 25 μM PMSF, pH 6.7, allows for dramatically improved fluorescent images compared to those obtained using conventional staining procedures, with residual background staining being reduced to near zero.The immunofluorescent images obtained using this technique provide information on several motile events that occur during the first cell cycle. This technique demonstrates that all of the cytoplasmic microtubules are associated with the incorporated sperm's centrioles during female pronuclear migration. This changes during the centration of the male and female pronuclei at which time a monastral array of microtubules forms in the egg's cytoplasm. A large proportion of the monastral microtubules do not appear to be associated with the centrioles. At prophase and early metaphase, the centrioles are the dominant microtubule organizing centers (MTOCs) consistent with mitotic theories that the kinetochore catches, but does not initiate, microtubules. Observations of intercentriolar distances show that there are three stages of pole separation during the first cell cycle. The initial separation occurs during pronuclear centration, the second during the streak stage, and the final one during the late stages of mitosis. At telophase, polar microtubules appear to extend into the cortex supporting the cell surface at all regions except the presumptive cleavage site.
    Additional Material: 7 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970030303
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  • 19
    Electronic Resource
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    Masthead (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970030401
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  • 20
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    Characterization of the chlamydomonas flagellar collar (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 273-280 
    Details
    ISSN: 0886-1544
    Keywords: Chlamydomonas flagellar collars ; Chlamydomonas cell wall ; mating in Chlamydomonas ; cell wall proteins ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The flagella of Chlamydomonas reinhardtii protrude through the cell wall via short, tunnel-like openings that are lined with 11 nm × 500 nm fibers arranged in parallel array. These cylindrical collections of fibers presumably permit free movement of the flagella within the cell wall. In this report electron-microscopic evidence is presented showing that during the initial stages of the mating reaction intact collars slip off of the ends of the flagella when cell wall loss occurs. Electrophoretic analysis of isolated collars reveals one major protein and several minor species.
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    URL: http://dx.doi.org/10.1002/cm.970030307
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  • 21
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    Crawling caenorhabditis elegans spermatozoa contact the substrate only by their pseudopods and contain 2-nm filaments (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 333-347 
    Details
    ISSN: 0886-1544
    Keywords: Caenorhabditis elegans spermatozoa ; cell motility ; electron microscopy ; cell-substrate contact ; 2-nm filaments ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The locomotion of C. elegans spermatozoa resembles, in many respects, the crawling movements of other eukaryotic cells. However, these sperm contain surprising little actin, which plays no apparent role in this cell's motility. Electron microscopy has revealed that crawling spermatozoa retain a strict morphological polarity so that the organelle-filled cell body is separated from the pseudopod by an array of cytoplasmic laminar membranes. When sperm crawl only the pseudopod contacts the substrate; the cell body is either pulled behind or carried on top of the rear portion of the pseudopod. Fingerlike projections which extend forward from the leading edge of the pseudopod initiate contact with the substrate. The underside of the pseudopod exhibits areas of close (40 nm separation) membrane-substrate association with intervening areas of wide (up to 300 nm) membrane-substrate gaps. The pseudopod cytoplasm contains 2-nm filaments but no filamentous actin has been observed. These 2-nm filaments were detected in thin sections of crawling cells and in negative-stained remnants of spermatozoa disrupted by either hypotonic buffer on Triton X-100. The filaments are found both free in the cytoplasm and closely associated with the cytoplasmic face of the plasma membrane and are usually oriented along the long axis of the cell. Neither the identity nor the function of these filaments has been established although their location and orientation suggest that they may be involved in generating propulsion.
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    Changes in cytoskeletal proteins of polymorphonuclear leukocytes induced by chemotactic peptides (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 349-361 
    Details
    ISSN: 0886-1544
    Keywords: myosin phosphorylation ; actin polymerization ; chemotactic factors ; leukocytes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Changes in the state of polymerization of actin and phosphorylation of myosin have been observed in polymorphonuclear leukocytes (PMNs) soon after the addition of the chemotactic peptide N-formylnorleucylleucylphenylalanine. At a time when the cells are observed to extend many ruffles or lamellipodia from their surface, the fraction of the cellular actin present in a monomeric form is decreased by about 25% as assayed by the ability of the G-actin to inhibit DNAase. These changes are temporally correlated with an increase in the staining by nitrobenzooxadiazole (NBD)-phallacidin, a probe that binds F-actin selectively. The NBD-phallacidin staining is observed in the surface ruffles. When the peptide concentration is decreased by addition of a tenfold excess of buffer, cells withdraw their surface ruffles and form blebs. These changes correlate with an increase in the G-actin levels detected with the DNAase inhibition assay. An increase in phosphorylation of the 20,000-dalton light chain of myosin is also observed in leukocytes stimulated by addition of chemotactic peptide. These observations of changes in cytoskeletal proteins of PMNs provide a beginning for further studies on the regulation of cell motility by chemotactic factors.
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    Organization and function of structural elements in focal contacts of tissue culture cells (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 391-397 
    Details
    ISSN: 0886-1544
    Keywords: focal contacts ; microfilaments ; microinjection ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The role of structural elements in the organization and maintenance of focal contacts was studied by microinjecting into tissue culture cells specific probes which interfere with filamentous actin or with vinculin: actin interaction. Injection of actin capping proteins from Physarum and brain resulted in breakdown of microfilament bundles starting at their distal ends and in loss of focal contacts. This process was fully reversible. Injection of a high affinity antibody against chicken gizzard vinculin led to partial breakdown of microfilament bundles concomitant with disruption of focal contacts with vinculin remaining at the plasma membrane. This process was irreversible.
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    Structural connections of the muscle-tendon junction (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 431-438 
    Details
    ISSN: 0886-1544
    Keywords: myotendinous junction ; laminin ; type IV collagen ; heparan sulfate proteoglycan ; alpha actinin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The muscle-tendon junction of murine skeletal muscles has been analyzed by a variety of extraction techniques, by myosin subfragment-1 binding experiments, and by ultrastructural immunocytochemistry. The results indicate that the muscle-tendon junction is composed of four distinct domains: an intracellular domain, the internal lamina; a domain connecting the internal lamina with the lamina densa of the external lamina, the connecting domain; the lamina densa; and a domain which attaches the lamina densa to the collagen fibers, the matrix. Each of these domains is distinct with respect to position, three-dimensional organization, and molecular composition, and is therefore considered to have a unique role in the transmission of contractile force.
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    A covalently cross-linked matrix in skeletal muscle fibers (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 463-483 
    Details
    ISSN: 0886-1544
    Keywords: intracellular matrix ; extracellular matrix ; covalently cross-linked matrix ; ε-(γ-glutamic) lysine bonds ; skeletal muscle ; titin ; covalently cross-linked collagen ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: When skeletal, cardiac, and smooth muscle is exhaustively extracted with a protein-unfolding reagent such as 6 M guanidine HCl and a disulfide-reducing reagent such as 5% β-mercaptoethanol, a tissue ghost remains intact and retains the characteristic shape and dimensions of the tissue before extraction. In the case of chicken pectoral muscle, the tissue ghost contains 1% of the original muscle proteins. Guanidine HCl extraction followed by collagenase treatment of glycerol-extracted chicken pectoral muscle releases a clean preparation of elongated structures containing 0.2% of the original protein and representing the covalently cross-linked remnants of the muscle fibers. The material of these muscle fiber ghosts extends throughout the interior of the cell. Antibodies raised against the tissue ghosts of smooth muscle cross-react with glycerol extracted skeletal myofibrils, forming a banding pattern which coincides with the banding pattern observed when myofibrils are reacted with antibodies against titin. Titin, a large and soluble protein found in skeletal muscle, cross-reacts with our antigizzard antibody. However, amino acid analysis of the muscle fiber ghosts indicates that titin cannot be the only subunit of the insoluble polymer, but that one or more proteins with a very high glycine and alanine content and a very low basic and acidic amino acid content must also form part of the covalently cross-linked matrix. The possibility is presented that this matrix may be the basis of the superthin 2-3-nm filaments which have been observed in a variety of cell types.
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    Actin-mediated surface motility during sea urchin fertilization (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 513-524 
    Details
    ISSN: 0886-1544
    Keywords: fertilization ; actin ; microfilaments ; sea urchin ; cell division ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The sea urchin egg at fertilization is an ideal model in which to study actin-mediated surface activity. Electron microscopy of unfertilized eggs demonstrates the presence of thousands of well-arrayed short microvilli, which appear supported by cytochalasin-sensitive actin oligomers as detected with rhodamine-labeled phalloidin staining of permeabilized eggs. At insemination, the previously short microvilli elongate and cluster around the successful sperm during incorporation. Phalloidin staining demonstrates a tremendous recruitement of polymerized actin into the site of sperm incorporation, resulting in the formation of the fertilization cone. Fertilization of cytochalasin-treated eggs results in the normal activation of the metabolic and bioeletric events, but sperm incorporation does not occur since the localized actin assembly required for fertilization cone formation is precluded. After sperm incorporation, the entire fertilized surface is restructured, as a result of a massive polymerization of actin to produce a burst in microvillar elongation. Addition of cytochalasin to eggs immediately following sperm incorporation demonstrates the recruitment of actin assembly for the proper progression through the first cell cycle. During normal cell divison, the egg surface retains the long microvilli. The furrow which forms at cytokinesis does not appear as a unique new structure, but rather as a reorganization of the cortical microfilaments. Quantitative fluorescence microscopy argues against an increase in microfilaments during early cytokinesis. At the latest stages of cytokinesis, a thickening of the cortical actin is noted, which could possibly be interpreted as a contractile ring. A minor basal level of actin assembly with numerous nucleation sites in unfertilized eggs and a tremendous but localized assembly of microfilaments surrounding the sperm during incorporation, followed by a massive global microfilament assembly event to elongate the fertilized egg microvilli resulting later in the reorganization of these microfilaments to produce the forces necessary for cytokinesis, highlight the utility of the study of sea urchin eggs at fertilization for understanding actin-membrane interactions.
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    Cell surface and cytoskeletal interactions in a temperature-sensitive strain of SV40-transformed mouse fibroblasts (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 553-565 
    Details
    ISSN: 0886-1544
    Keywords: microfilaments ; cytoskeleton ; simian virus 40 ; cell adhesion ; cell surface ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In order to assess the role of cytoskeletal structure in modulating cell surface topography during cell transformation, cytoskeletal organization of 3T3 mouse cells transformed with a tsA mutant of simian virus 40 (SV40) was studied in detail by correlative light and electron microscopy. Detergent-extracted, criticalpoint dried whole cells observed in the electron microscope were seen to contain well-organized microfilament bundles (stress fibers) traversing the longitudinal axis of cells grown at the restrictive temperature (39°C). When grown at the permissive temperature (32°C), cells prepared in this manner were not observed to contain such structures. However, when semithin sections (0.5 μm) were viewed by transmission electron microscopy at 120 kV, short microfilament bundles were seen in 32°C-grown cells. There was an alteration in the morphology of these structures at sites of attachment to the substratum (focal contacts), and they were shorter in length than microfilament bundles of 39°C-grown cells. A difference was also observed between the two phenotypes in the layer of microfilaments associated with the dorsal cell surface. Since it is this layer that directly determines cell surface architecture, it is proposed that changes in microfilament bundle-generated surface tension are responsible for alterations of this layer, leading to an altered cell surface morphology. Tension may be modified by disturbances in focal contacts (or adjacent regions) or altered actin-associated protein(s).
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    Effects of abnormal cytoskeletal structure on erythrocyte membrane mechanical properties (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 609-622 
    Details
    ISSN: 0886-1544
    Keywords: erythrocyte membrane ; surface elastic shear modulus ; membrane viscosity ; hereditary disorders of blood ; membrane yield ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Measurements of the mechanical properties of the erythrocyte membrane provide a direct assessment of the proper function of its structural components. To assess the effects of alterations in molecular structure on membrane mechanical properties, measurements have been performed on cells from six individuals whose membranes contain inherited, biochemically characterized structural defects. Because the contribution of the memmbrane skeleton to the mechanical behavior of the membrane is most evident in shear deformation, mechanical experiments were performed to measure the material constants which characterize the response of the membrane to shear force resultants. The surface elastic shear modulus characterizes the elastic response of the membrane; the yield shear resultant is the maximum shear force resultant which the membrane can support elastically; and the plastic viscosity coefficient characterizes the rate of membrane deformation when the elastic limit has been exceeded.Generally, it was found that when the molecular defect is found to occur in a region of the skeleton which is stress-supporting, the maximum elastic strength of the membrane is reduced. However, the magnitude of the reduction can be quite different for membranes having similar or even identical defects. In some cases the differences can be attributed to the removal of the most fragile cells of the population by the spleen, but other results indicate that the biochemical description of the defects may be incomplete. These results emphasize the need for further refinements both in the biochemical characterization of membrane skeleton structure and in the description and measurement of membrane mechanical properties.
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    Effects of folic acid upon filopodia of Dictyostelium discoideum vegetative amoebae (1984)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 129-135 
    Details
    ISSN: 0886-1544
    Keywords: amoeboid motion ; chemoattractants ; chemotaxis ; Dictyostelium ; filopodia ; folic acid ; pterins ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Living vegetative D. discoideum amoebae were studied to determine whether their filopodia respond to folic acid, a chemoattractant for these cells. Exponentially growing amoebae (ca. 10 μm diameter) exhibit 5-30 μm long filopodia; at stationary phase, aggregation competent amoebae have numerous multibranched filopodia up to 100 μm long. Folic acid was observed to stimulate production, elongation, and branching of filopodia with its effects progressively changing as the amoebae approach aggregation. Filopodial construction was also found to be dependent upon Mg2+ levels. The significance of these results is discussed with respect to progressive changes within the vegetative phase as well as to the mechanisms of amoeboid movement, pseudopodial activity, and chemotaxis.
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    Intracellular movement of fodrin (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 649-655 
    Details
    ISSN: 0886-1544
    Keywords: axonal transport ; lymphocyte capping ; spectrin ; fodrin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fodrin is an actin/calmodulin-binding protein with similarities to spectrin (erythrocytes) and TW 260/240 (brush border). It is concentrated beneath the plasma membranes of neurons and other cells. We have observed translocations of fodrin in both neurons and lymphocytes. Newly synthesized, radiolabeled fodrin moves down axons at a maximum velocity (about 50 mm/day) that is slower than the most rapidly axonally transported proteins (group I). A portion of fodrin appears to move more slowly at velocities (1-10 mm/day) resembling those of actin and myosin (group IV) and tubulin and neurofilament proteins (group V). In lymphocytes, when certain surface antigens are induced by cross-linking agents to migrate to one pole of the cell and form a cap, fodrin redistributes beneath the membrane and forms a subcap. The movements of fodrin in lympohocyte capping and in the axonal transport of group IV polypeptides have certain similarities. In both cases, the redistribution of fodrin is accompanied by concomitant redistributions of actin, myosin, and calmodulin, and both processes proceed at similar velocities. We consider the possibilities that these two processes are related, both being driven by a submembrane force-generating system comprising in part actin, myosin, and fodrin, and that fodrin serves to link various organelles or proteins to this system.
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    A quantitative comparison of cellular motile systems (1984)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 1-5 
    Details
    ISSN: 0886-1544
    Keywords: motility ; power output ; muscle ; flagella ; cytokinetic furrow ; mitotic spindle ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cellular motile systems as diverse as muscle and the mitotic spindle have been compared by their specific power output: the maximum power they develop per unit of engine volume. Striated muscles and flagella have high specific output; their performance is comparable to that of typical automobile engines. The cytokinetic furrow and the mitotic spindle have very much lower specific power output. The furrow's output is 7,000 times lower than muscle and the spindle's is 300,000 times lower. Different macromolecules have been used to generate power in systems with similar output (muscles and flagella) and, conversely, the same macromolecular motor has been used in systems with very different output (muscles and cytokinetic furrows). The common feature amid this diversity is adaptation to a particular biological role, which specific power output reflects very well. High values are found where a powerful, compact engine should be advantageous, while low values are found where precision, not power, matters most.
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    Announcement (1984)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 76-76 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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    Coupling of photomovement and photosynthesis in desmids (1982)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982), S. 73-82 
    Details
    ISSN: 0886-1544
    Keywords: desmids ; videomicrography ; photokinesis ; photophobic response ; photophosphorylation ; photosynthesis ; phototaxis ; uncouplers ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effects of the uncouplers CCCP and DNP on photokinesis, phototaxis, and the photophobic response in the desmid Cosmarium have been studied both in population systems and by videomicrographic, single-cell analysis. Light-dependent motility is specifically inhibited by both uncouplers, indicating that photokinesis is driven by photophosphorylation. In population experiments, phototaxis and accumulations in light traps due to photophobic responses are inhibited by drug concentrations comparable to those that inhibit photokinesis. Analysis of single-cell behavior demonstrated, however, that neither photophobic responses elicited by an increase in light intensity (step-up response) nor by a decrease (stepdown response) are inhibited, as long as the reduced motility allows the organisms to cross a light--dark border. Phototactic orientation is not impaired by DNP in the single cell analysis, but CCCP significantly reduced the degree of orientation. The results indicate that, although chlorophyll is the photoreceptor for all three photoresponses, at least the photophobic response is independent of both the photosynthetic electron transport chain and photophosphorylation.
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    Instructions for contributors (1982)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982), S. 91-92 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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    Masthead (1982)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
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    A motile system of singlet microtubules in spermatozoa (1982)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982), S. 93-101 
    Details
    ISSN: 0886-1544
    Keywords: cell motility ; singlet microtubules ; dynein ; coccid insect ; aflagellate spermatozoa ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In this report we demonstrate that in the coccid insects Pseudococcus, Phenacoccus, and Planococcus the whole spermatozoon is made up by a nuclear central core surrounded by two complete and one incomplete turns of concentric microtubule palisades. Microtubules of the outer row are linked by a system of short projections 6 nm long; those of the inner row are linked to each other by similar arms; a second system of 6 nm arms links the tubules of each inner row to those of the respective outer row. All these systems of arms are longitudinally spaced every ∼ 12 nm. The motility of this spermatozoon is due to waves progressing from the posterior extremity to the anterior one. By SDS polyacrylamide gel electrophoresis a group of high molecular weight polypeptides is detected, one of which migrates in coincidence with the A dynein band from sea urchin sperm. Our data suggest that occurrence in coccid spermatozoon of a motility due to singlet tubules-dynein interaction.
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    Effects of phalloidin microinjection and localization of fluorescein-labeled phalloidin in living sand dollar eggs (1982)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982), S. 103-113 
    Details
    ISSN: 0886-1544
    Keywords: actin ; cleavage ; fluorescein-labeled phalloidin ; microinjection ; phalloidin ; sand dollar eggs ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Effects of microinjection of phalloidin on fertilization and cleavage of sand dollar (Clypeaster japonicus and Scaphechinus mirabilis) eggs were studied. The drug, previously injected into unfertilized eggs, showed no effect on the elevation of the fertilization membrane upon insemination up to an intracellular concentration of 50 μM. However, the movement of the egg pronucleus to the sperm pronucleus was inhibited and the fusion of pronuclei did not occur. The subsequent development no longer took place. When phalloidin was injected into fertilized eggs, the thickness of the cortical layer increased and the microvilli became conspicuous. Both nuclear division and cleavage were inhibited at the intracellular concentration of more than 20 μM, though the latter seemed to be more sensitive to phalloidin than the former.Fluorescein-labeled phalloidin (FL-phalloidin) was injected into eggs in order to investigate F-actin localization by fluorescence microscopy. In both unfertilized and fertilized eggs, FL-phalloidin was localized in the cortical layer within 1 min after injection. It was also localized in the cortical layer as radially oriented rodlike structures when injected into fertilized eggs before the disappearance of the nuclear membrane. No distinct fluorescence was detected in the mitotic apparatus or in the cleavage furrow. FL-phalloidin redistributed gradually into egg cytoplasm. In unfertilized eggs, fluorescent rods were found especially in the egg pronucleus 30 min after injection.
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    Tomato actin and myosin: Contractile proteins from a higher land plant (1982)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982), S. 131-147 
    Details
    ISSN: 0886-1544
    Keywords: higher land plant contractile system ; actin activation of myosin ; S-1 decoration of actin ; polymerization of actin ; calcium sensitivity of actomyosin interaction ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: This paper describes the initial isolation of actin- and myosin-like proteins from the cytoplasm of the endocarp tissue cells of the fruit of the tomato, Lycopersicon esculentum. Low ionic strength buffers extracted the 42,000 molecular weight tomato actin in the depolymerized form. Tomato actin can be polymerized in 0.1 M KCl, 2 mM MgCl2 to form 6 nm diameter filaments resembling rabbit skeletal muscle F-actin in their ultrastructure and pattern of decoration with rabbit myosin subfragment-1 (S-1). Tomato F-actin activates the low ionic strength Mg2+ ATPase of rabbit S-1 up to ten-fold. High ionic strength extracts of tomato yield a myosinlike enzyme whose ATPase activity in 0.5 M KCl is maximal in the presence of K+-EDTA and is repressed in the presence of Mg2+. The column-purified enzyme forms a complex with rabbit F-actin, which can be dissociated by Mg2+ ATP. The low ionic strength Mg2+ ATPase of tomato myosin can be activated ten-fold by rabbit actin and up to nineteen-fold by tomato actin. No activation of the tomato myosin by rabbit F-actin occurs in the absence of free calcium ions.
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    Cell locomotion in vitro by Xenopus laevis gastrula mesodermal cells (1982)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982), S. 149-161 
    Details
    ISSN: 0886-1544
    Keywords: cell locomotion ; gastrulation ; contact paralysis ; collagen substratum ; serum factors ; morphogenetic movements ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Prospective mesodermal cells of Xenopus laevis gastrulae showed substantial locomotion in vitro, averaging 4.3 μM/min, when dissociated and cultured on a glass surface coated with collagen and fetal bovine serum. The cell translocate by making lamellipodia and filopodia whereas the main cell body remains rounded. When two mesodermal cells made contact with each other, they showed contact paralysis of lamellipodial activity. In contrast, when mesodermal cells contact ectodermal cells, contact paralysis does not occur. Rather, migrating mesodermal cells continue to translocate. The locomotion in vitro appears to mimic that in vivo during gastrulation, because of the similarities of the rate of movement and the cell shape in culture and in embryos. Neither prospective ectodermal cells from gastrulae nor prospective mesodermal cells from blastulae showed locomotion under the same culture conditions.
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    High-speed cinematographic analysis of the movement of Chlamydomonas (1985)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 5 (1985), S. 251-263 
    Details
    ISSN: 0886-1544
    Keywords: Chlamydomonas ; movement ; flagellar beat ; stigma ; high-speed microcinematography ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Using high-speed microcinematography (100-500 f/s) the movement of Chlamydomonas reinhardtii mutant 622 E has been studied with frame-by-frame analysis. The stigma lies in the cell equator, displaced out of the flagellar plane anticlockwise by an angle of about 45°. During forward movement the cells rotate anticlockwise about their long axis with a frequency of 1.4-2 Hz (maximum 2.5 Hz). The rotation is caused by a lateral component of 3-dimensional beating of the flagella during the effective strokes. The helical swimming path is a result of an unequal flagellar beating. This is normally synchronous, but synchrony is interrupted from time to time by an additional beat of the outward directed flagellum, in our study one after about every twenty beats on average. These results are discussed and compared with the results published by other groups.
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    URL: http://dx.doi.org/10.1002/cm.970050307
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    Masthead (1985)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 5 (1985) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970050501
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    Newt lung ciliated cell models: Effect of MgATP on beat frequency and waveforms (1985)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 5 (1985), S. 377-392 
    Details
    ISSN: 0886-1544
    Keywords: newt ; lung ; cilia ; beat frequency ; waveform ; models ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Highly coupled newt lung ciliated cell models were used to study the effects of MgATP concentration on ciliary beat frequency and waveform. Models were prepared from ciliated lung cells of the newt Taricha granulosa by trypsin dissociation of the epithelium, demembranation with Triton X-100, and reactivation with MgATP, as described previously [Weaver and Hard, 1985]. Beat frequencies were measured stroboscopically. Ciliary waveforms of reactivated models and intact mucociliary epithelial sheets were determined by single frame analysis of high-speed movies. Waveform parameters calculated included the durations of the effective and recovery strokes, the angular velocities of the ciliary base and tip, the position of the bend along the ciliary shaft during the recovery stroke, the velocity of recovery stroke bend propagation, and the ratio of the duration of recovery stroke bend propagation to the duration of the recovery stroke itself. We found that beat frequency varied biphasically in response to MgATP at 21°C, as shown previously for isolated, individual, newt lung axonemes. Apparent Fmax (maximum beat frequency) and Km values of 25 Hz and 0.14 mM, and 35 Hz and 0.47 mM, respectively, were obtained for each linear segment of the biphasic double reciprocal plot. Demembranation did not alter either ciliary waveform or the pattern of coordination. In this system, metachrony is antilaeoplectic and ciliary waveform appears to be regulated independent of beat frequency.
    Additional Material: 8 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970050503
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    A model for fast axonal transport (1985)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 5 (1985), S. 507-527 
    Details
    ISSN: 0886-1544
    Keywords: axonal transport ; microtubules ; organelles ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A model for fast axonal transport is developed in which the essential features are that organelles may interact with mechanochemical cross-bridges that in turn interact with microtubules, forming an organelle-engine-microtubule complex which is transported along the microtubules. Computer analysis of the equations derived to describe such a system show that most of the experimental observations on fast axonal transport can be simulated by the model, indicating that the model is useful for the interpretation and design of experiments aimed at clarifying the mechanism of fast axonal transport.
    Additional Material: 5 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970050607
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    Editorial (1986)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 6 (1986), S. 1-1 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970060102
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    Isolation of cilia from porcine tracheal epithelium and extraction of dynein arms (1986)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 6 (1986), S. 25-34 
    Details
    ISSN: 0886-1544
    Keywords: respiratory cilia ; dynein ; ATPases ; porcine trachea ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Milligram amounts of mammalian ciliary axonemes were isolated from porcine tracheas. These were reactivated upon addition of ATP, indicating intact functional capability with a mean beat frequency at 37°C of 8.2 Hz. Electron microscopy showed typical ultrastructure of the isolated demembranated axonemes. Electrophoresis into polyacrylamide gradient gels containing sodium dodecyl sulfate revealed reproducible protein profiles from ten different tracheal preparations. Four major protein bands were observed in the 300-330 K molecular weight region, as well as tubulin at 51-54K. Extraction of the isolated tracheal axonemes with 0.6M KCl removed the outer dynein arms seen in electron microscopic cross-section of axonemes, preferentially solubilized two of the high molecular weight proteins at 320 and 330 K, and resulted in a three- to four-fold increase in ATPase specific activity. Sedimentation of the dialyzed salt extract on a 5-30% sucrose density gradient and subsequent fractionation yielded two peaks of ATPase activity. The faster migrating, 19S major ATPase peak correlated with the 320 and 330 K proteins, and two other proteins at 81 and 67 K. The slower sedimenting, 12S minor ATPase peak corresponded to a 308 K protein and two smaller proteins at 33 and 48 K. Thus, the outer dynein arm of tracheal cilia appeared to be associated with at least two high molecular weight proteins. These results demonstrate that adequate quantities of functionally intact axonemes can be reproducibly isolated from porcine tracheas, allowing further fractionation and analysis of mammalian cilia.
    Additional Material: 12 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970060105
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    Masthead (1986)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 6 (1986) 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970060301
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    Prelimlnary report on the ultrastructural organization of the contractile appendix of Tontonia appendiculariformis (ciliophora oligotrichina) (1986)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 6 (1986), S. 217-224 
    Details
    ISSN: 0886-1544
    Keywords: contractile system ; microfilaments ; microtubules ; endoplasmic reticulum ; ciliophora ; oligotrichina ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Tontonia appendiculariformis is a marine planktonic ciliate with a long tail. The tail can contract rapidly, becoming transformed into an oval mass one-twentieth of its original length. The highly complex ulrastructure of the tail is described here in detail. A large part of the volume of the tail contains numerous more or less parallel membranous tubes. The membrane of the tubes has numerous invaginations and is probably derived from the smooth endoplasmic reticulum. This tubular material forms a continuous layer around the tail, interrupted in only one region, which contains cilia. Associated with the cilia are basal fibres with a periodically banded appearance. The tubular layer forms several folds separated by hyaloplasm containing many mitochondria. The pellicle of the tail is thrown into numerous pleats. It comprises a perilemma, a plasmalemma, and complex alveoli, but epiplasm and microtubules are absent. The alveoli appear to form septa within the folds of the layer of membranous tubes. In the region where the tail is attached to the body of the ciliate there are conspicuous bundles of microtubules and microfilaments. The membranous tubes and septa appear to be connected to small bundles of microfilaments, which presumably represent the contractile material. However, we consider the membranous tubes as potentially active in producing the change in shape. Although the structure of the tail of Tontonia is unique, there are certain similarities to the stalk of the Tintinnina and also to the motile extension of the dinoflagellate Erythropsidinium.
    Additional Material: 10 Ill.
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    URL: http://dx.doi.org/10.1002/cm.970060221
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    Robert Day Allen (1927-1986): An appreciation (1986)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 6 (1986), S. 249-255 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970060302
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    A model for the molecular basis of filament contractility and sliding as demonstrated by helix models (1986)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 6 (1986), S. 229-236 
    Details
    ISSN: 0886-1544
    Keywords: α-helix ; filament motility ; filament contractility ; filament sliding ; microtubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The twisting behavior of α helices has hardly been considered hitherto with regard to the function of proteins. The well-known electrostatic repulsion between the highly charged side chains, which depends on their interaction with ions, is absolutely connected with torsional rotations of the helix as long as its hydrogen bonds hold. This means a direct transformation of chemical into mechanical energy. However, the stability of a twisted single α helix with charged side chains is low in an aqueous environment. It may easily ball up to form a globular molecule with nonhelical regions of the polypeptide chain. This corresponds to a primitive contraction that obviously occurs with spasminlike proteins that contain strongly twisted filaments as Salisbury [J. Submicrosc. Cytol. 15:105-110, 1983] has shown. Steps that increase the stability and rigidity of α helical filaments are (1) the formation of coiled-coils, (2) self-intertwining (“telephone cord phenomenon”) or intertwining with other coiled-coils as shown with the intermediate filaments, and (3) association with cytoskeletal elements (microfilaments, protofilaments of microtubules) that contain globular subunits. These coarser elements are rotated by winding and unwinding of the smaller helical molecules and thus transmit the torsion produced in the α helices to the microscopic level by the sliding (screwing) motion and the shearing effect that is connected with the waves of a rotating helix. Particles are transported if connected to the helical side arms. Since the displacement of the side arms seems to occur along the single protofilaments of a microtubule, a rotation of these protofiiaments is suggested. The bidirectional transport of particles along single microtubules may be explained by the association of left- and right-handed helices with the protofilaments. According to the models, parallel and antiparallel sliding of neurofilaments and neurotubules is suggested.
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    URL: http://dx.doi.org/10.1002/cm.970060223
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    Regulation of ciliary motility by membrane potential in Paramecium: A role for cyclic AMP (1986)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 6 (1986), S. 256-272 
    Details
    ISSN: 0886-1544
    Keywords: ciliary motility ; cAMP regulation ; swimming speed ; membrane potential ; detergent models ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The membrane potential of Paramecium controls the frequency and direction of the ciliary beat, thus determining the cell's swimming behavior. Stimuli that hyperpolarize the membrane potential increase the ciliary beat frequency and therefore increase forward swimming speed. We have observed that (1) drugs that elevate intracellular cyclic AMP increased swimming speed 2-3-fold, (2) hyperpolarizing the membrane potential by manipulation of extracellular cations (e.g., K+) induced both a transient increase in, and a higher sustained level of cyclic AMP compared to the control, and (3) the swimming speed of detergent-permeabilized cells in MgATP was stimulated 2-fold by the addition of cyclic AMP. Our results suggest that the membrane potential can regulate intracellular cAMP in Paramecium and that control of swimming speed by membrane potential may in part be mediated by cAMP.
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    URL: http://dx.doi.org/10.1002/cm.970060303
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