ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Cell & Developmental Biology  (13,116)
  • 1995-1999  (2,509)
  • 1990-1994  (6,449)
  • 1980-1984  (2,672)
  • 1975-1979  (1,486)
Collection
Keywords
Publisher
Years
Year
  • 101
    Electronic Resource
    Electronic Resource
    Cytokinesis is more rapid in Ha-T24-ras transfected rat embryo fibroblasts than in non-transfected control cells (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 159-166 
    Details
    ISSN: 0886-1544
    Keywords: neoplastic cells ; mitotic cells ; metaphase ; protein kinase C ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: It has long been known that neoplastic cells are characterized by increases in cell motility. Earlier studies from this laboratory indicated that rnitotic events were also altered in many tumor and experimentally transformed cells and that this included increases in metaphase duration and a reduction in the duration of cytokinesis. The studies presented in this paper were done to determine whether or not transfection of normal rat embryo fibroblasts by the Ha-T24-ras oncogene could also produce such alterations in mitotic events. The results obtained with the use of time lapse video microscopy indicate that neither the duration of metaphase nor the rate of chromosome movement during anaphase was altered but that the rate of furrow progression during cytokinesis occurred at a significantly more rapid rate. Thus, the cellular alteratioons induced by transfection with Ha-T24-ras accelerate microfilament-dependent cytokinetic furrowing without significant effects on microtubule-dependent mitotic events. One of several possible mechanisms that could account for these observations involves a down regulation of protein kinase C which has been reported to occur in many neoplastic cells including those transformed by ras. Such a hypothesis could also have broader implications because it may be applicable to the increase in motility and metastatic activity generally observed in transformed cells.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970210209
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 102
    Electronic Resource
    Electronic Resource
    Reactivation of newt lung cilia: Evidence for a possible temperature- and MgATP-induced activation mechanism (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 187-198 
    Details
    ISSN: 0886-1544
    Keywords: amphibian ; respiratory ; axonemes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Optimal conditions have been developed for the isolation and reactivation of highly coupled, demembranated ciliary axonemes from newt lungs [Hard, Cypher, and Schabtach, 1988, Cell Motil. Cytoskeleton 10:271-284]. In the present study, the motility of these cilia was further characterized by examining the effects of nucleotides, divalent cations, and temperature on beat frequency. When exposed to a reactivating solution containing Mg2+ and ATP, nearly 100% of the axonemes were motile and beat at frequencies of 0-50 Hz, depending on [MgATP] and temperature. Divalent cations were required for movement, with Mg2+ 2-3 times more effective than Ca2+. There was no absolute requirement for Ca2+ for motility. The beat frequencies obtained with fixed ATP and varying Mg2+ concentrations indicate that MgATP serves as the actual substrate. The effects of MgATP on beat frequency depended on the degree of mechanochemical coupling and temperature and MgATP-induced transition between two distinct states whose maximum beat frequencies differ by 200-300%.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970210303
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 103
    Electronic Resource
    Electronic Resource
    A component of the interphase cytoskeleton is cyclically recruited into spindle poles during mitosis (1991)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 19 (1991), S. 80-90 
    Details
    ISSN: 0886-1544
    Keywords: centrosomes ; microtubules ; sea urchin embryos ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: During the transition from interphase to mitosis, proteins are recruited into forming spindle poles [Leslie, Cell Motil. Cytoskeleton 16:225-228, 1990]. Antibodies which recognize these recruited components clearly label spindle poles during mitosis but the location and character of such proteins during interphase remain a mystery. Competition assays using an antibody to a recruited spindle pole protein show that in its disperse form the spindle pole protein is a highly insoluble component of the Cytoskeleton which is dispersed to such an extent during interphase that it is difficult to identify by immunolocalization. The function of recruited spindle pole proteins is unknown but the aggregation/dispersion cycle and the antigen are highly conserved, appearing in sea urchin embryos and tissue culture cells.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970190203
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 104
    Electronic Resource
    Electronic Resource
    Trout sperm swimming patterns and role of intracellular Ca++ (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 74-82 
    Details
    ISSN: 0886-1544
    Keywords: motion analysis ; sperm activation ; K+inhibition ; Fluo-3 ; eukaryotic flagella ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We investigated the swimming patterns of trout sperm using computer-assisted analyses of video microscopy. Under full activation conditions, in which 80-100% of sperm activate their motility, sperm swim in circular paths for 2-5 sec, followed by 30-60 sec of a more linear swimming, and, finally, cessation of movement, with a straightening of the flagella. Threshold activation, in which 50% of the sperm activate, is characterized by circular patterns of swimming for less than 20 sec, with straightened flagella upon cessation. Full activation and threshold activation are observed in low-K+ solution or in an Mg++ -supplemented K+ solution. Similarities in swimming patterns in low-K+ solution and in a Mg++ -supplemented K+ solution suggest a common underlying mechanism of activation. Initiation of movement in solutions with high Ca++ to K+ ratio is similar to activation in K+ -free solution. However, sperm in Ca++ -supplemented media resume circular swimming within 20-25 sec after activation, and, upon cessation of movement, the flagella are frequently cane shaped or bent. Differences in swimming patterns upon activation by high Ca++ concentration suggest additional effects of Ca++ on regulating swimming patterns. We used the fluorescent Ca++ indicator Fluo-3 to measure changes in intracellular Ca++ concentration upon activation. Intracellular Ca++ concentration transiently increases upon activation, with peak Ca++ concentration coinciding with the period of circular swimming. This transient increase in Ca++ concentration is seen in the absence of external Ca++, providing strong evidence for the released of Ca++ from intracellular stores upon activation.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970210109
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 105
    Electronic Resource
    Electronic Resource
    The redeployment of F-actin in silk glands during moulting (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 101-110 
    Details
    ISSN: 0886-1544
    Keywords: F-actin ; silk gland ; phalloin ; periluminal circumferential actin bundles ; actin-coated vacuoles ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Labeling of silk glands with rhodaminyl-phalloin shows that most F-actin is restricted to parallel bundles that form rings around the gland lumen at the apical cell surface. The bundles are lost when larval feeding stops at moulting, and the F-actin is redistributed through the cytoplasm as coats to vacuoles and, occasionally, in variably oriented strands. After moulting there is a return to the distribution of filamentous actin in the apical periluminal rings of bundles. These events occur at the same time as F-actin in the nuclear shell [Henderson and Locke, submitted] undergoes its own set of changes. In silk gland cells two kinds of f-actin deployment take place concurrently.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970210203
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 106
    Electronic Resource
    Electronic Resource
    The role of β1 integrin in spreading and myofibrillogenesis in neonatal rat cardiomyocytes in vitro (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 87-100 
    Details
    ISSN: 0886-1544
    Keywords: myofibrils ; extracellular matrix ; cytoskeleton ; integrins ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The influence of the extracellular matrix (ECM) on cell behavior, myofibrillogenesis and cytoarchitecture was investigated in neonatal rat cardiac myocytes in vitro. Cell behavior was examined by analyzing cell spreading on different ECM components under a variety of experimental conditions. Area measurements were made on digitized images of cells grown for various time intervals on fibronectin (FN), laminin (LN), collagens I and III (C I + III), plastic, and bovine serum albumin (BSA). The amount of spreading was varied on the different matrices and was maximal on FN 〉 LN 〉 C I+III 〉 plastic 〉 BSA. Addition of anti-β1 integrin antibodies to myocytes cultured on FN, LN and C I+III blocked spreading outward on the substrates and altered normal myofibrillogenesis, especially on LN. Concomitantly, the integrin antibodies induced the formation of giant pseudopodial processes which protruded upward from the substrates. These pseudopods contained actin polygonal networks which exhibited a regular geometrical configuration.Effects of the ECM on cytoarchitecture was examined by analyzing the temporal and spatial patterns of fluorescence and immunogold labeling of cytoskeletal and integrin proteins as myocytes spread in culture. The first indication of sarcomeric patterns was the appearance at 4 hours of striations formed by lateral alignment of α-actinin aggregates into Z bands. At later times, vinculin at 8 hours and β integrin at 22 hours became co-localized with α-actinin at the Z bands and focal adhesions. These data indicate that ECM components influence myocyte spreading and that myofibril assembly and/or stability is associated with ECM-integrin-cytoskeleton associations.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970210202
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 107
    Electronic Resource
    Electronic Resource
    Cytoskeletal assembly and vinculin-cytoskeleton interaction in different phases of the activation of bovine platelets (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 123-131 
    Details
    ISSN: 0886-1544
    Keywords: thrombin ; cytochalasin B ; phorbol-myristate-acetate ; aggregation ; secretion ; contractile gel ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Vinculin is an Mr 130 kDa protein that has been implicated in membrane-cytoskeleton interaction in various cell types. It has been demonstrated that vinculin is not a cytoskeletal component in resting platelets, but part of it becomes associated with the cytoskeleton during thrombin-induced activation. In this study, using a quantitative immunnoblotting technique, the relation of vinculin to the cytoskeleton in different phases of activation of bovine platelets was explored, and the process of incorporation of vinculin into the cytoskeleton was related to that of cytoskeletal assembly. The assembly of cytoskeleton proceeded at a significantly faster rate than the association of vinculin with it, which shows that the latter process is not due to passive trapping of vinculin into the Triton-insoluble residue, but certain biochemical changes had to occur before such an interaction became possible. When the formation of pseudopodia was prevented by cyto-chalasin B, but neither aggregation nor the release reaction induced by thrombin were inhibited, the recovery of vinculin in the Triton-insoluble residue even increased. In both time- and thrombin-concentration-dependent studies, poor correlation was found between vinculin-cytoskeleton association and the extent of aggregation. Activation with phorbol-myristate-acetate, which is a strong stimulus for aggregation but produces only a slight release in the granular content, resulted in the association of only a negligible amount of vinculin with the cytoskeletal fraction. The incorporation of vinculin into the cytoskeletal fraction of thrombin activated platelets started with the release reaction but still proceeded, and the greatest part of the reaction occurred after secretion had gone to completion. These findings suggest that platelet shape change and pseudopodium extrusion are not prerequisites for, and aggregation is not related to, vinculin-cytoskeleton interaction. The association of vinculin with the cytoskeleton correlates with the organization of contractile gel, which suggests a role for vinculin in secretion and clot retraction.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970210205
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 108
    Electronic Resource
    Electronic Resource
    Isolation and characterization of a unique 15 kilodalton trypanosome subpellicular microtubule-associated protein (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 138-146 
    Details
    ISSN: 0886-1544
    Keywords: MAP p15 ; microtubule bundling ; trypanosoma brucei ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A protein of 15 kDa (p15) was isolated from Trypanosoma brucei subpellicular microtubules by tubulin affinity chromatography. The protein bound tubulin specifically both in its native form and after SDS-PAGE in tubulin overlay experiments. p15 promoted both the in vitro polymerization of purified calf brain tubulin and the bundling of preformed mammalian microtubules. Immunolabeling identified p15 at multiple sites along microtubule polymers comprising calf brain tubulin and p15 as well as on the subpellicular microtubules of cryosectioned trypanosomes. Antibodies directed against p15 did not cross react with mammalian microtubules. It is suggested that p15 is a trypanosome-specific microtubule-associated protein (MAP) that contributes to the unique organization of the sub-pellicular microtubules.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970210207
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 109
    Electronic Resource
    Electronic Resource
    Characterization of tetramethylrhodaminyl-phalloidin binding to cellular F-actin (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 147-158 
    Details
    ISSN: 0886-1544
    Keywords: depolymerization ; DNase I ; association rate constant ; dissociation rate constant ; polymor-phonuclear leukocyte ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fluorescent derivatives of phallcidin are widely used to measure filamentous actin (F-actin) levels and to stabilize F-actin. We have characterized the kinetics and affinity of binding of tetramethylrhodaminy (TRITC)-phalloidin to rabbit skeletal muscle F-actin and to F-actin in lysates of rabbit polymorphonuclear leukocytes (PMNs). We have defined conditions where TRITC-phalloidin can be used to inhibit F-actin depolymerization and to quantify F-actin without prior fixation. By equi librium measurements, the affinity of TRITC-phalloidin binding to rabbit skeletal muscle F-actin (pyrene labeled) or to PMN lysate F-actin was 1-4 × 10-7 M. In both cases, the stoichiometry of binding was approximately 1:1. Kinetic measurements of TRITC-phalloidin binding to PMN lysate F-actin resulted in an association rate constant of 420 ± 120 M-1 sec-1 and a dissociation rate constant of 8.3 ± 0.9 ± 10-5 sec-1. The affinity calculated from the kinetic measurements. (2 ± 1 × 10-7 M) agreed well with that obtained by equilibrium measurements. The rate with which 0.6 μM TRITC-phalloidin inhibited 0.1 μM pyrenyl F-actin depolymerization (90% inhibition in 10 sec) was much faster than the rate of binding to pyrenyl F-actin (〈1% bound in 10 sec), suggesting that phalloidin binds to filament ends more rapidly than to the rest of the filament. We show that TRITC-phalloidin can be used to measure F-actin levels in cell lysates when G-actin is also present (i.e., in cell lysates at high concentrations) if DNase I is included to prevent phalloidin-induced polymerization.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970210208
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 110
    Electronic Resource
    Electronic Resource
    Reactivation of outer-arm-depleted lung axonemes: Evidence for functional differences between inner and outer dynein arms in situ (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 199-209 
    Details
    ISSN: 0886-1544
    Keywords: amphibian ; respiratory ; cilia ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Demembranated axonemes isolated from newt lung ciliated cells show a complex beat frequency response to varying [MgATP] and temperature [Hard and Cypher, 1992, Cell Motil. Cytoskeleton 21:187-198]. The present study was undertaken to ascertain whether the beat frequency of outer-arm-depleted newt lung axonemes is controlled in a manner similar to that of intact axonemes. Populations of demembranated ciliary axonemes were isolated by Triton X-100 extraction of lungs from the newt, Taricha granulosa. Aliquots of the demembranated axonemes were further treated with solutions containing high salt (0.375 M KCl) and 1.25 mM MgATP. This treatment resulted in the selective removal of outer dynein arms and a concomitant decrease in beat frequency to a stable level, 33-35% of control values. The effects of pH, salt concentration, nucleotides, and temperature on the beat frequency of reactivated outer-arm-depleted axonemes were ascertained and compared with those of intact axonemes. Some reactivation properties, such as nucleotide specificity, the effect of pH on beat frequency and the threshold [MgATP] required for reactivation (approximately 5 μM) were similar to those observed for intact axonemes. Other properties, such as the relationship between beat frequency and varying [MgATP] or salt concentration, differed both qualitatively and quantitatively from those of control axonemes, as did their response to temperature over the range, 5°-32°C. The nature of the results obtained with temperature and MgATP suggests that inner and outer dynein arms are not functionally equivalent in situ.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970210304
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 111
    Electronic Resource
    Electronic Resource
    Distribution of profilin in fibroblasts correlates with the presence of highly dynamic actin filaments (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992), S. 51-61 
    Details
    ISSN: 0886-1544
    Keywords: immuno-gold localization ; lysis-squirting ; lamellipodium ; actin dynamics ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have used polyclonal and monoclonal antibodies raised against calf thymus profilin to localize the corresponding protein in translocating, spreading, and stationary rat fibroblasts. Immunofluorescence of whole cells and immunogold labeling on ventral membranes of lysis-squirted cells showed that profilin was markedly enriched in the highly dynamic lamellipodia or pseudopodial lobes. Within these regions, a significant fraction was colocalized with dynamic actin filaments organized in actin ribs, cortical filaments, or stress fiber-like bundles, and little profilin was found in membrane areas appearing free of actin. In contrast, stress fibers of stationary cells as well as actin arcs and ring-like bundles of spreading and migrating cells showed very little label. These results are discussed in context with the proposed role of profilin in regional membrane dynamics typical for fibroblasts and are compared to previous data (Hartwig et al.: J. Cell Biol. 109:1571-1579, 1989) on profilin distribution in platelets and granulocytes. © 1992 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970220106
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 112
    Electronic Resource
    Electronic Resource
    Activation of maternal centrosomes in unfertilized sea urchin eggs (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 23 (1992), S. 61-70 
    Details
    ISSN: 0886-1544
    Keywords: activation ; fertilization ; microtubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Centrosomes are undetectable in unfertilized sea urchin eggs, and normally the sperm introduces the cell's microtubule-organizing center (MTOC) at fertilization. However, artificial activation or parthenogenesis triggers microtubule assembly in the unfertilized egg, and this study explores the reappearance and behavior of the maternal centrosome. During activation with A23187 or ammonia, microtubules appear first at the cortex; centrosomal antigen is detected diffusely throughout the entire cytoplasm. Later, the centrosome becomes more distinct and organizes a radial microtubule shell, and eventually a compact centrosome at the egg center organizes a monaster. In these activated eggs, centrosomes undergo cycles of compaction and decompaction in synchrony with the chromatin, which also undergoes cycles of condensation and decondensation. Parthenogenetic activation with heavy water (50% D2O) or the microtubule-stabilizing drug taxol (10 μM) induces numerous centrosomal foci in the unfertilized sea urchin egg. Within 15 min after incubation in D2O, numerous fine centrosomal foci are detected, and they organize a connected network of numerous asters which fill the entire egg. Taxol induces over 100 centrosomal foci by 15 min after treatment, which organize a corresponding number of asters. The centrosomal material in either D2O- or taxol-treated eggs aggregates with time to form fewer but denser foci, resulting in fewer and larger asters. Fertilization of eggs pretreated with either D2O or taxol shows that the paternal centrosome is dominant over the maternal centrosome. The centrosomal material gradually becomes associated with the enlarged sperm aster. These experiments demonstrate that maternal centrosomal material is present in the unfertilized egg, likely as dispersed undetectable material, which can be activated without paternal contributions. At fertilization, paternal centrosomes become dominant over the maternal centrosomal material. © 1992 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970230107
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 113
    Electronic Resource
    Electronic Resource
    Masthead (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 23 (1992) 
    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.970230201
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 114
    Electronic Resource
    Electronic Resource
    Association of glycosphingolipids with intermediate filaments of mesenchymal, epithelial, glial, and muscle cells (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 255-271 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeleton ; globoside ; vimentin ; desmin ; keratin ; glial fibrillary acidic protein ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We reported recently that two glycosphingolipids (GSLs), globoside (Gb4)and ganglioside GM3, colocalized with vimentin intermediate filaments of human umbilical vein endothelial cells. To determine whether this association is unique to endothelial cells or to vimentin, we analyzed a variety of cell types. Doublelabel immunofluorescent staining of fixed, permeabilized cells, with and without colcemid treatment, was performed with antibodies against glycolipids and intermediate filaments. Globoside colocalized with vimentin in human and mouse fibroblasts, with desmin in smooth muscle cells, with keratin in keratinocytes and hepatoma cells, and with glial fibrillary acidic protein (GFAP) in glial cells. Globoside colocalization was detected only with vimentin in MDCK and HeLa cells, which contain separate vimentin and keratin networks. GM3 ganglioside also colocalized with vimentin in human fibroblasts. Association of other GSLs with intermediate filaments was not detected by immunofluorescence, but all cell GSLs were detected in cytoskeletal fractions of metabolically labelled endothelial cells. These observations indicate that globoside colocalizes with vimentin, desmin, keratin and GFAP, with a preference for vimentin in cells that contain both vimentin and keratin networks. The nature of the association is not yet known. Globoside and GM3 may be present in vesicles associated with intermediate filaments (IF), or bound directly to IF or IF associated proteins. The prevalence of this association suggests that colocalization of globoside with the intermediate filament network has functional significance. We are investigating the possibility that intermediate filaments participate in the intracellular transport and sorting of glycosphingolipids.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970210402
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 115
    Electronic Resource
    Electronic Resource
    Colchicine-binding sites of brain tubulins from an Antarctic fish and from a mammal are functionally similar, but not identical: Implications for microtubule assembly at low temperature (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 272-280 
    Details
    ISSN: 0886-1544
    Keywords: cold-stable microtubules ; cold adaptation ; cytoskeleton ; antimitotic drugs ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The tubulins of Antarctic fishes possess adaptations that favor microtubule for mation at low body temperatures (Detrich et al.: Biochemistry 28:10085-10093, 1989). To determine whether some of these adaptations may be present in a domain of tubulin that participates directly or indirectly in lateral contact between microtubule protofilaments, we have examined the energetics of the binding of colchicine, a drug thought to bind to such a site, to pure brain tubulins from an Antarctic fish (Notothenia gibberifrons) and from a mammal (the cow, Bos taurus), At temperatures between 0 and 200C, the affinity constants for colchicine binding to the fish tubulin were slightly smaller (1.5-2.6-fold) than those for bovine tubulin. van't Hoff analysis showed that the standard enthalpy changes for colchicine binding to the two tubulins were comparable (δH° = + 10.6 and + 7.4 kcal mol-1 for piscine and bovine tubulins, respectively), as were the standard entropy changes (δS° = +61.3 eu for N. gibberifrons tubulin, +51.2 eu for bovine tubulin). At saturating concentrations of the ligand, the maximal binding stoichiometry for each tubulin was ∼ 1 mol colchicine/mol tubulin dimer. The data indicate that the colchicine-binding sites of the two tubulins are similar, but probably not identical, in structure. The apparent absence of major structural modifications at the colchicine site suggests that this region of tubulin is not involved in functional adaptation for low-temperature polymerization. Rather, the colchicine site of tubulin may have been conserved evolutionarily to serve in vivo as a receptor for endogenous molecules (i.e., “colchicine-like” molecules or MAPs) that regulate microtubule assembly.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970210403
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 116
    Electronic Resource
    Electronic Resource
    Different assembly properties of cod, bovine, and rat brain microtubules (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992), S. 305-312 
    Details
    ISSN: 0886-1544
    Keywords: tubulin ; acetylated detyrosinated tubulin ; estramustine phosphate ; heparin ; poly-L-aspartic acid ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Assembly properties of cod, bovine, and rat brain microtubules were compared. Estramustine phosphate, heparin, poly-L-aspartic acid, as well as NaCl, inhibited the assembly and disassembled both bovine and rat microtubules by inhibition of the binding between tubulin and MAPs. The assembly of cod brain microtubules was in contrast only marginally affected by these agents, in spite of a release of the MAPs. The results suggest that cod tubulin has a high intrinsic ability to assemble. This was confirmed by studies on phosphocellulose-purified cod tubulin, since the critical concentration for assembly was independent of the presence or absence of MAPs. The results show therefore that cod brain tubulin has, in contrast to bovine and rat brain tubulins, a high propensity to assemble under conditions which normally require the presence of MAPs.Even if cod MAPs, which have an unusual protein composition, were not needed for the assembly of cod microtubules, they were able to induce assembly of bovine brain tubulin. Both cod and bovine MAPs bound to cod microtubules, and bovine MAPI and MAP2 bound to, and substituted at least the 400 kDa cod protein. This suggests that the tubulin-binding sites and the assembly-stimulatory ability of MAPs are common properties of MAPs from different species, independent of the tubulin assembly propensity.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970210406
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 117
    Electronic Resource
    Electronic Resource
    Masthead (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 23 (1992) 
    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.970230401
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 118
    Electronic Resource
    Electronic Resource
    Mapping the mammalian intercellular bridge (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 23 (1992), S. 231-235 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970230402
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 119
    Electronic Resource
    Electronic Resource
    Microtubule oscillations (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992), S. 235-244 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970220403
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 120
    Electronic Resource
    Electronic Resource
    Association of the β isoform of protein kinase C with vimentin filaments (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992), S. 250-256 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeletal localization ; signal transduction ; intermediate filaments ; rat basophilic leukemia cells ; translocation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Protein kinase C (PKC) isoforms are key mediators in hormone, growth factor, and neurotransmitter triggered pathways of cell activation (Nishizuka: Science 233:305-312, 1986; Nature 334:661-665, 1988). Stimulation of kinase activity by diacylglycerol and calcium often leads to translocation of PKC from the cytosol to a particulate fraction (Kraft and Anderson: Nature 301:621-623, 1983). The β isoform of PKC is translocated and degraded much more rapidly than the β isoform in phorbolester-stimulated rat basophilic leukemia (RBL) cells (Huang et al.: J. Biol. Chem. 264:4238-4243, 1989). We report here immunofluorescence evidence that the distributions of PKC α and β are strikingly different in antigen-activated RBL cells. PKC β associates with perinuclear filaments and filaments that extend from the perinuclear area to the cell periphery whereas PKC β concentrates in regions of the cell periphery. This distribution of PKC β is distinctly different from that of actin filaments and microtubules as determined by phalloidin staining and by anti-tubulin antibody labeling. In contrast, the staining patterns obtained with antibodies to PKC β and to the intermediate filament protein vimentin are almost identical, indicating that PKC β associates with vimentin filaments. These bundles of 100 Å filaments may provide docking sites for interactions of PKC β with its substrates and thus confer specificity to the actions of this isoform. © 1992 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970220405
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 121
    Electronic Resource
    Electronic Resource
    Characterization of smooth muscle caldesmon as a microtubule-associated protein (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 23 (1992), S. 244-251 
    Details
    ISSN: 0886-1544
    Keywords: actin ; in vitro motility assay ; microtubule bundling ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have previously shown that nonmuscle caldesmon copurified with brain microtubules binds to microtubules in vitro [Ishikawa et al.: FEBS Lett. 299:54-56, 1992]. To explore the role of caldesmon in the functions of microtubules, further characterization was performed using smooth muscle caldesmon, whose molecular structure and function have been best-characterized in all caldesmon species.Smooth muscle caldesmon bound to microtubules with a stoichiometry of five tubulin dimers to one molecule of caldesmon with the binding constant of 1.1 × 106M-1. The binding of caldesmon to microtubules was inhibited in the presence of Ca2+ and calmodulin. Partial digestion of the caldesmon with α-chymotrypsin revealed that the binding site of the caldesmon for microtubules lay in the 34-kDa C-terminal domain. When the caldesmon was in the dimeric form in the absence of a reducing agent, the caldesmon cross-linked microtubules to form bundles. Further, the caldesmon potentiated the polymerization of tubulin, and inhibited the in vitro movement of microtubules on dynein. These results suggest that caldesmon may be involved in the regulation by Ca2+ of the functions of microtubules. © 1992 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970230404
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 122
    Electronic Resource
    Electronic Resource
    Organization of cortical microfilaments in dividing root cells (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 23 (1992), S. 252-264 
    Details
    ISSN: 0886-1544
    Keywords: Allium ; Tradescantia ; actin ; cell cortex ; division plane determination ; immunocytochemistry ; mitosis ; microtubules ; preprophase band ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In order to assess the possible role of microfilaments (Mfs) in events preceding plant cell division, actin was localized in root cells of Allium cepa and Tradescantia virginiana by immunofluorescence microscopy. The distribution of Mfs was compared to that of microtubules (Mts) by means of dual localizations employing both antiactin and antitubulin. Cycling interphase cells contain Mfs that extend into all regions of the cytoplasm in random fashion. Prior to the rearrangement of the cortical Mt array into the initial broad preprophase band (PPB), the number of Mfs in the cytoplasm decreases, while a new population appears in the cortex. The cortical Mfs, which usually occupy the entire cell surface, are aligned parallel to the cortical Mts. When the initial PPB appears, these Mfs still cover the cortex or are arranged as a broad band encompassing the PPB. As the PPB narrows, the Mfs are also confined to an increasingly restricted zone usually wider than the PPB.than the PPB. When the PPB reaches its narrowest, densest configuration, aligned Mfs are excluded from the band proper, while others appear in flanking regions of the cortex. From prometaphase through anaphase, cortical Mfs are largely restricted to the ends of the cell overlying the spindle poles; they also tend to become more randomly oriented. Little or no actin is present in the spindle. During telophase, the two zones of aligned cortical Mfs over the ends of the cell gradually disappear and are replaced by new interphase networks. These changes provide additional data on the possible control of PPB organization by actin, and in addition indicate that the cortex may be the origin of the actin that aggregates at the spindle poles during cytochalasin treatment. © 1992 Wiley-Liss, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970230405
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 123
    Electronic Resource
    Electronic Resource
    A shell of F-actin surrounds the branched nuclei of silk gland cells (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 23 (1992), S. 169-187 
    Details
    ISSN: 0886-1544
    Keywords: nuclear actin ; nuclear myosin ; nuclear shell ; nuclear shape ; nuclear matrix ; silk gland ; nuclear structure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The branched nuclei from silk gland cells of larvae of Calpodes ethlius label with antibodies to actin and myosin and with rhodaminyl-phalloin, which is specific for f-actin. Optical sectioning localizes this actin and myosin to the nuclear periphery. Residual nuclear-associated fractions prepared from these cells contain sheets of nuclear lamina-like structures that bind heavy meromyosin and gold-tagged antibodies to actin and myosin. The results suggest that both actin and myosin, or a myosin-like protein, are components of a layer at the nucleocytoplasmic boundary that we call the nuclear shell. The nuclear shell appears to be associated with the nuclear envelope and may correspond to a zone on the cytoplasmic face of the envelope seen in electron micrographs of unextracted cells. The residual nuclear-associated fraction has a unique isoform of actin (43 kD, pl 6.45) that might allow the nuclei to associate with an actin network structurally and developmentally distinct from that of the cytoplasm. © 1992 Wiley-Liss, Inc.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970230302
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 124
    Electronic Resource
    Electronic Resource
    Expression of desmin cDNA in PtK2 cells results in assembly of desmin filaments from multiple sites throughout the cytoplasm (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 23 (1992), S. 188-200 
    Details
    ISSN: 0886-1544
    Keywords: intermediate filaments ; desmin ; vimentin ; assembly ; transfection ; microinjection ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The assembly of intermediate filaments into a cytoplasmic network was studied by microinjecting into the nuclei and cytoplasms of PtK2 cells, plasmids that contained a full length desmin cDNA and an RSV promoter. Immunofluorescence was used to monitor the expression of desmin and its integration into the cells' vimentin intermediate filament network. We found that the expressed desmin co-localized with filaments of vimentin just as it does when fluorescently labelled desmin is microinjected into the cytoplasm of PtK2 cells. As early as two hours after microinjection of the plasmids, small discrete dots and short fragments of desmin could be detected throughout the cytoplasm of the cells. This initial distribution of desmin was superimposed on the filamentous pattern of vimentin in the cells. At 8 hours after microinjection of the plasmids, some of the desmin was present in long filaments that were coincident with vimentin filaments. By 18 hours, most of the desmin was in a filamentous network co-localizing with vimentin. There was no indication that desmin assembly began in the perinuclear region and proceeded toward the cell periphery. In some cells, excessively high levels of desmin were expressed. In these cases, overexpression led to clumping of desmin filaments as well as to an accumulation of diffusely distributed desmin protein in the center of the cells. This effect was apparent at approximately 18 hours after introduction of the plasmid. The native vimentin filaments in such cells were also aggregated around the nucleus, colocalizing with desmin. The microtubule networks in all injected cells appeared normal; microtubules were extended in typical arrays out to the periphery of the cells. © 1992 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970230303
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 125
    Electronic Resource
    Electronic Resource
    Desmosome assembly in MDCK epithelial cells does not require the presence of functional microtubules (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 23 (1992), S. 201-212 
    Details
    ISSN: 0886-1544
    Keywords: intercellular junctions ; desmosome ; assembly ; microtubules ; epithelia ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Desmosomes, complex multisubunit structures that assemble at sites of cell-cell contact, are important components of the epithelial junctional complex. Desmosome assembly requires the coordinated interaction at the plasma membrane of at least 8 cytoplasmic and integral membrane proteins organized into two structurally and functionally distinct domains, the cytoplasmic plaque and membrane core. Previous studies (Pasdar et al., J. Cell Biol., 113:645-655) provided evidence that cytokeratin filaments and microtubules may regulate transfer and assembly of cytoplasmic plaque and membrane core proteins, respectively. To determine directly the role of microtubules in these processes, Madin-Darby canine kidney (MDCK) cells were treated with nocodazole or colchicine to disrupt the microtubular network. Biochemical analysis of the different components of the cytoplasmic plaque and membrane core domains revealed little or no effect of nocodazole or colchicine on the kinetics of synthesis, post-translational modifications, transfer of proteins to the plasma membrane or their metabolic stability in the presence or absence of cell-cell contact. Likewise, immunofluorescence analysis of desmosome formation demonstratedan apparently normal desmosome assembly in the presence of nocodazole or colchicine upon induction of cell-cell contact. These results indicate that an intact microtubular network is not necessary for the processing or transport of the desmosomal membrane core glycoproteins to the plasma membrane in the absence or presence of cell-cell contact. Furthermore, the integration of the cytoplasmic plaque and membrane core domains induced by cell-cell contact at the plasma membranes of adjacent cells does not require the presence of functional microtubules. © 1992 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970230304
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 126
    Electronic Resource
    Electronic Resource
    LC20 and kinetics of gizzard myosin subfragment-1: Digestion with papain vs. S. aureus protease (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 23 (1992), S. 213-221 
    Details
    ISSN: 0886-1544
    Keywords: actin-activated ATPase ; LC20 cleavage ; phosphorylation ; HMM ; actin affinity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Previous reports have shown that papain-digested gizzard subfragment-1 (PAP-S1) has a cleaved regulatory light chain (LC20), and Vmax similar to phosphorylated heavy meromyosin (HMM) Greene et al., Biochemistry 22:530-535, 1983; Sellers et al., J. Biol. Chem. 257:13880-13883, 1982; Umemoto et al., [J. Biol. Chem. 264:1431-1436, 1989], while S. aureus protease-digested S-1 (SAP-S1) has intact LC20, but Vmax closer to that of unphosphorylated HMM [Ikebe and Hartshorne, 1985]. To determine whether intact LC20 inhibits ATPase activity for subfragment- 1 (S1), we compared the kinetic properties and structures of unphosphorylated PAP-S1 and SAP-S1. SDS-PAGE showed that SAP-S1 had 68 and 24 KDa heavy chain and 20 and 17 KDa light chain components. PAP-S1 (15 minutes digestion at 20°C) also had 68 and 17 KDa bands, but the single 24 KDa band (24HC) was replaced by a group of 22-24 KDa fragments and LC20 was cleaved to a 16 KDa fragment. At 13 mM ionic strength, both PAP-S1 and SAP-S1 had Vmax similar to phosphorylated HMM (1.1-1.5 s-1). SAP-S1 had the same KATPase as phosphorylated HMM (38 μM actin). but KATPase for PAP-S1 was 3-fold stronger (11 μM actin). Subsequent digestion of SAP-S1 with papain did not significantly change Vmax, but as LC20 and 24HC were cleaved, both KATPase and Kbinding strengthened 3- to 5-fold. Thus, intact LC20 did not inhibit, and cleavage of LC20 did not increase Vmax for S1. Rather, papain cleavage of LC20 and 24HC was associated with strengthened actin binding. © 1992 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970230305
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 127
    Electronic Resource
    Electronic Resource
    Masthead (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 21 (1992) 
    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.970210201
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 128
    Electronic Resource
    Electronic Resource
    Dynamics of polar filament discharge and sporoplasm expulsion by microsporidian spores (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992), S. 38-50 
    Details
    ISSN: 0886-1544
    Keywords: cytomechanics ; invasion mechanisms ; kinematic analysis ; parasites ; protoplasm flow ; video microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Spores of the microsporidium Nosema algerae were stimulated to germinate in vitro while observed with video-enhanced contrast microscopy. Field-by-field playback of tape-recorded sequences yielded the first serial illustrations and kinematic analysis of the explosive discharge of the polar filament and the sporoplasm. The filament emerges from the anterior pole of the spore in a regularly pitched helicoidal course along a nearly straight axis, with a mean maximum instant velocity of 105 μm/s. Just before elongation is completed the filament tip follows a tortuous path that often results in a curved or spiralling terminal configuration. Then elongation stops and, after a lag that may vary from less than 15 to over 500 ms, the sporoplasm pours out at the filament tip forming a globule that quickly grows up to a size larger than its original volume within the spore. Concomitantly, the helical filament becomes straightened and frequently the spore body is pulled forward. Thereafter a relaxed filament, usually 5-10% shorter than when maximally extended, remains connecting the empty spore case and the sporoplasmic droplet. Experiments with hyperosmolar media produced a considerable slowdown of filament extrusion and often precluded sporoplasm discharge. The present results are fully consistent with the hypothesis of a hydrostatic pressure-triggered mechanism of spore germination, and revealed that the process is composed of two discrete phases separated by a variable lag: (1) complete eversion of the polar filament, and (2) passage of the main sporoplasm mass along the tube. The data provide a preliminary basis toward the conception of a quantitative physical model of microsporidian spore germination. © 1992 Wiley-Liss, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970220105
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 129
    Electronic Resource
    Electronic Resource
    Actin in the ciliated protozoan Climacostomum virens: Purification by DNAse I affinity chromatography, electrophoretic characterization, and immunological analysis (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992), S. 62-71 
    Details
    ISSN: 0886-1544
    Keywords: actin filaments ; actin isoforms ; anti-actin monoclonal antibodies ; cytoskeleton ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The anti-actin monoclonal antibody (mab) JLA20 (Lin: Proc. Natl. Acad. Sci. U.S.A. 78:2335-2339, 1981) labels a 43 kD protein on Western blots of Climacostomum cell extracts; this protein does not react with an anti-α-smooth muscle actin mab (Skalli et al.: J. Cell Biol. 103:2787-2796, 1986) nor with an anti-α-sarcomeric actin mab (Skalli et al.: Am. J. Pathol. 130:515-531, 1988). This protein binds to DNAse I and can be purified by DNAse I affinity chromatography. The affinity-purified actin also reacts with mab JLA20. Two-dimensional gel analysis reveals that Climacostomum actin focuses as three spots which are more basic than the mammalian actin isoforms. After addition of KC1, the affinity-purified actin polymerizes into filaments as shown by electron microscopy after negative staining. © 1992 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970220107
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 130
    Electronic Resource
    Electronic Resource
    Native microtubules with a variable number of protofilaments (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 49-53 
    Details
    ISSN: 0886-1544
    Keywords: insect sperm tail ; trichopteran axoneme ; computer image analysis ; axonemal ultrastructure ; accessory tubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Insect spermatozoa are characterized by having a set of accessory tubules that surrounds the microtubular doublets of the axoneme and that are formed from the B-subtubules of the doublets. In trichopteran species, the accessory tubules have an unusually large diameter. Those of one species, Odontocerum albicorne, were seen to have a number of protofilaments that is 19 in the main part of the axoneme, but gradually decreasing to 18, 17, and 16 near the distal tip. The accessory tubule of the trichopteran axoneme has an asymmetrical shape and a skewed orientation, which makes it easy to distinguish a tubule that is viewed from its plus-end from one viewed from the minus-end. The shape of a cross-sectioned protofilament in the trichopteran accessory tubules differs from that of microtubules in general, including accessory tubules of other insects, by being polygonal with the most acute angle pointing centripetally. © 1993 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970240106
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 131
    Electronic Resource
    Electronic Resource
    Morphology of nexin links in relation to interdoublet sliding in the sperm flagellum (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 109-118 
    Details
    ISSN: 0886-1544
    Keywords: motility ; flagellum ; spermatozoon ; nexin ; freeze-etch ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In this work, we examine whether the “nexin” linkages of the flagellum can extend in length to accommodate interdoublet sliding. Flagellar bends of large angle were induced in bull spermatozoa by hypotonic treatment. It is argued that this produces large interdoublet displacements that are, nevertheless, still within physiological limits. Such flagella were examined by the rapid-freeze, deep-etch techique and the nexin linkages identified by their position in relation to the inner dynein arms and by their straplike, bipartite, morphology. They were found to bridge perpendicularly (or occasionally at an angle) between the A- and B-tubules of adjacent doublets. The nexin linkages were no more than ∼20 nm in length, even in regions in which ∼200 nm of sliding could be inferred. Variable registration between adjacent nexin rows gave some further support to the assumption that sliding had indeed taken place. From this, it is concluded that elastic deformation of the links, such as would accommodate interdoublet sliding, does not occur; some form of displacement must occur between nexin and the adjacent B-tubule. © 1993 Wiley-Liss, Inc.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970240204
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 132
    Electronic Resource
    Electronic Resource
    Video microscopy of organelle inheritance and motility in budding yeast (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 129-142 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeleton ; mitochondria ; vacuole ; kinesin ; myosin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: By adapting the time-lapse video microscopy techniques that were developed for larger, more complex cells, to living Saccharomyces cerevisiae cells, intracellular organelle movements were observed. Differential interference contrast optics revealed an organelle transport process in cells treated with mating pheromone. Small particles were observed to travel distances of up to 6 μm at rates of 0.11-0.17 (and in one case 0.80) μm/sec. Overall, the frequency of these motile events was quite low compared to what is observed in cell types traditionally studied by video microscopy. The ability to discern clearly the vacuole and nucleus in budding yeast revealed the dynamics of these organelles and the fact that their movements are carefully orchestrated during the cell cycle. Two types of vacuolar dynamics were observed: (1) interconversion between one large organelle and numerous smaller organelles and (2) the formation of projections that extend from the mother cell's vacuole into the bub. When applied to the study of the many available cytoskeletal and cell cycle mutants, the application of video microscopy to the study of organelle movements in living yeast cells will provide a unique opportunity to determine the molecular mechanisms of intracellular motility and to elucidate the temporal controls over these processes. © 1993 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970250203
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 133
    Electronic Resource
    Electronic Resource
    Tipping of flagellar agglutinins by gametes of Chlamydomonas reinhardtii (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 179-189 
    Details
    ISSN: 0886-1544
    Keywords: mating reaction ; migration ; cross-linked agglutinins ; gametic flagellar tips ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The migration of cross-linked agglutinins to the gametic flagellar tips (tipping) is a hallnmark of the Chlamydomonas mating reaction. In this study, an assay was developed to analyze the kinetics and biological requirements for the tipping response: isolated flagella from mt- gametes of C. reinhardtii were allowed to agglutinate to the immotile flagella of pf-18 mt+ gametes, and their migration to the tips was monitored by phase microscopy. The tipping process is shown to require both adhesion and elevated levels of cAMP. The cAMP may activate tipping motors directly. In addition, cAMP stimulates the recruitment of agglutinins to flagellar surface to replace those inactivated by adhesion. These results are compared with previous studies on the tipping of flagellar surface proteins cross-linked by soluble ligands, and an integrated model is presented. © 1993 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970250207
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 134
    Electronic Resource
    Electronic Resource
    Characterization of spontaneous and action potential-induced calcium transients in developing myotubes in vitro (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 143-157 
    Details
    ISSN: 0886-1544
    Keywords: calcium ; muscle cultures ; C2 cells ; development ; sarcoplasmic reticulum ; T-tubules ; calcium release channel ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have investigated the onset and maturation of action potential- and calcium-induced calcium release from the sarcoplasmic reticulum during the differentiation of excitation-contraction coupling in skeletal muscle. Microfluorometry and video imaging of cultured myotubes loaded with the fluorescent calcium indicator fluo-3 revealed the dynamics, time course, and physiological properties of calcium transients as well as their changes during development. Spontaneous and stimulated contractions in well-differntiated myotubes are accompanied by brief (200-500 ms) increases in the concentration of free cytoplasmic calcium. These transients are modulated by sub-threshold concentrations of caffeine, resulting in a plateau of elevated calcium. Two novel types of calcium transients were observed in non-contracting myotubes. (1) Fast localized transients (FLTs) are radially restricted focal release events that occur spontaneously within the myoplasm at various densities and frequencies. (2) Upon addition of caffeine, propagating calcium waves are generated (35-70 μm/s velocity), which are accompanied by contractures. Aside from caffeine sensitivity, calcium waves and contractionrelated sustained release events are similar in amplitude and duration, as well as in their inactivation and refractory properties. Thus, these transients may represent calcium-induced calcium release in quiescent and active myotubes, respectively. Following one calcium-induced calcium release event, myotubes become refractory to new calcium-induced transients; however, action potential-induced transients and FLTs are not blocked. This suggests that these transients occur by distinct release mechanisms and that dual modes of calcium release exist prior to the coupling of calcium release to excitation. © 1993 Wiley-Liss, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970250204
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 135
    Electronic Resource
    Electronic Resource
    Rises of intracellular Ca2+ and pH mediate the initiation of sperm motility by hyperosmolality in marine teleosts (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 171-178 
    Details
    ISSN: 0886-1544
    Keywords: sperm ; motility ; osmolality ; intracellular Ca2+ ; intracellular pH ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Spermatozoa of marine teleosts, puffers and flounder, wee completely quiescent when they were washed to remove electrolytic components of the seminal plasma and then diluted in nonelectrolyte solutions isotonic to the seminal plasma. Sperm motility was initiated upon dilution in hypertonic nonelectrolyte solutions. These observations suggest that sperm motility is suppressed by seminal osmolality and motility is triggered solely by the increase in external osmolality which occurs at natural spawning in hypertonic seawater. Extracellular Ca2+ had no influence on the osmolality-dependent initiation of sperm motility. However, sperm motility was initiated even in isotonic solution when Ca2+ was introduced into the sperm cells by Ca2+ ionophore. Intracellular Ca2+ increased at the osmolality-dependent initiation of sperm motility under Ca2+ -free conditions. These results suggest that the release of Ca2+ from intracellular storage in response to the increase in external osmolality has a key role in the initiation of sperm motility. A transient increase in intracellular pH was also observed at the hyperosmolality-dependent initiation of sperm motility. Furthermore, initiation of sperm motility was induced even in isotonic solutions when intracellular pH increased by the treatment with ammonium salts. These results suggest that an increase in intracellular pH, as well as the rise in intracellular Ca2+, has an important role in the initiation of sperm motility in marine teleosts. © 1993 Wiley-Liss, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970250206
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 136
    Electronic Resource
    Electronic Resource
    High level expression of nonacetylatable α-tubulin in Chlamydomonas reinhardtii (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 158-170 
    Details
    ISSN: 0886-1544
    Keywords: acetylation ; epitope-tagging ; flagella ; tubulin isoforms ; microtubules ; rubisco ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Following the discovery of acetylated α-tubulin in the flagella of Chlamydomonas, many studies have documented the presence of acetylated α-tubulin in a variety of evolutionarily divergent organisms. While this posttranslational modification may define an isoform with a unique function, the primary effect of α-tubulin acetylation remains unknown. To study the function of α-tubulin acetylation, we have transformed Chlamydomoas, a organism in which almost all of the flagellar tubulin ad a subset of the cytoplasmic microtubules are acetylated, with a α1-tubulin gene whose product cannot be acetylated. Specifically, the codon for lysine 40, the lysine that is acetylated, has been replaced with the codons of nonacetylatable amino acids. To distinguish mutagenized α-tubulin from that produced by the two endogenous α-tubulin genes, mutant α-tubulin was tagged with an epitope from influenza virus hemagglutinin. Utilizing the constitutive Chlamydomonas rubisco small subunit S2 promoter, we have obtained in selected clones high levels of nonacetylatable α-tubulin expression approximating 50-70% of the total flagellar α-tubulin. Immunofluorescence and immunoblot analysis of transformed cells indicated that nonacetylatable α-tubulin could assemble, along with endogenous α-tubulin, into both cytoplasmic and flagellar microtubules. However, no gross phenotypic effects were observed, suggesting that the effect of α-tubulin acetylation is subtle. © 1993 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970250205
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 137
    Electronic Resource
    Electronic Resource
    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993) 
    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.970250301
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 138
    Electronic Resource
    Electronic Resource
    Phalloidin binds and stabilizes pea root actin (1992)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 22 (1992), S. 245-249 
    Details
    ISSN: 0886-1544
    Keywords: rhodamine phalloidin ; anti-chicken actin antibody ; plant actin ; DNase I ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Previous reports about phalloidin binding to plant actins have been indirect. We present here evidence showing that phalloidin does bind and stabilize filaments of actin extracted from pea roots. Criteria for the presence of actin included stabilization as a polymer in the presence of phalloidin, cross-reaction with antibody against chicken actin, affinity binding to DNase I, and ability to be decorated by the S1 fragment of rabbit muscle myosin.Phalloidin was able to stabilize polymers in pea root extracts against dissociation during SDS gel electrophoresis, and these polymers were shown to be composed exclusively of actin. Pea root actin isolated by affinity chromatography on a DNase I column was incubated with rhodamine phalloidin and electrophoresed on a native gel. The rhodamine fluorescence remained with the stabilized filaments, indicating clearly that phalloidin does bind to actin from a plant source. © 1992 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970220404
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 139
    Electronic Resource
    Electronic Resource
    Microtubule-associated motility in cytoplasmic extracts of sea urchin eggs (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 167-178 
    Details
    ISSN: 0886-1544
    Keywords: cytoplasmic dynein ; kinesin ; bundling ; crosslinking ; video microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have developed a method for producing sea urchin egg cytoplasmic extracts which support substantial microtubule-associated motility, particularly minus end-directed motility characteristic of cytoplasmic dynein. Particles translocated along microtubules and axonemes predominantly in the minus end direction; microtubules and axonemes glided across the coverslip surface only in the plus end direction (as expected for a minus-end directed motor bound to the coverslip surface); and microtubules crosslinked into bundles in an antiparallel orientation. Velocities of particle and microtubule translocation were in the range of 0.5-1.8 μm/sec. Vanadate at 10 μM inhibited all gliding of the microtubules and axonemes, yet bidirectional particle transport persisted. Vanadate at concentrations of 25 μM and higher inhibited nearly all microtubule-based motility in the preparation and produced parallel bundling of the microtubules. Motility was slowed but not stopped in the presence of 5 mM AMP-PNP.Usually when a particle bound to a microtubule wall, it moved to the microtubule minus end. These particles often remained attached to the minus end. When a microtubule plus end in the shortening phase of dynamic instability reached a stationary particle on the microtubule, sometimes normal minus enddirected motility was activated, or at other times the particle remained attached to the shortening plus end. © 1993 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970240304
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 140
    Electronic Resource
    Electronic Resource
    Control of profilin and actin expression in muscle and nonmuscle cells (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 179-188 
    Details
    ISSN: 0886-1544
    Keywords: protein synthesis ; northern analysis ; BC3H1 cells ; HepG-2 cells ; C2C12 cells ; profilactin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Profilin is a small G-actin binding protein implicated in sequestering actin monomers in vivo. We have quantitated profilin and actin expression in human hepatoma HepG-2 cells and in two mouse myogenic cell lines, BC3H1 and C2C12, to determine whether the expression of profilin and the expression of nonmuscle isoactin or total actin are co-regulated. During differentiation of both muscle cell types, profilin and nonmuscle actin expression decrease in a coordinate manner as shown by measurements of steady state mRNA and newly synthesized protein. In human hepatoma HepG-2 cells, the twofold increase in actin synthesis observed after 24 hours of exposure to cytochalasin D did not result in an increase in profilin synthesis. Thus, profilin and actin expression are not coregulated in all cells. To determine if there is sufficient profilin to sequester a large portion of cellular G-actin, we measured total profilin and G-actin levels in the three cell types. In each case, profilin accounted for less than 10% of the total G-actin on a molar basis. Thus, profilin is not responsible for total G-actin sequestration in these cells. Finally, using poly-L-proline affinity chromatography, we showed that, in the cell types tested, less than 20% of the poly-L-proline purified profilin existed as a complex with G-actin. The profilin in these cells may be interacting with cellular components other than actin. © 1993 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970240305
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 141
    Electronic Resource
    Electronic Resource
    Myosin-I in mammalian liver (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 189-199 
    Details
    ISSN: 0886-1544
    Keywords: myosin-I ; liver ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Myosin-I refers to a class of proteins with a molecular weight of approximately 110-kDa, which have characteristics of conventional myosin but are unable to form filaments. Previous studies have implicated myosin-I in motile cellular processes including cell migration and phagocytosis. Although the first example of myosin-I in higher eukaryotes was the intestinal 110K-calmodulin complex, which forms in microvilli the lateral links connecting the core bundle of actin filaments to the membrane, myosin-I has now been shown to be a component of rat kidney and to be present in bovine adrenal gland and brain. We have now purified and characterized two polypeptides from rat liver which have several characteristics of the intestinal 110K-calmodulin complex. Both liver polypeptides are solubilized with ATP and co-elute on gel filtration with calmodulin. The polypeptides, of 110-kDa and 130-kDa, bind calmodulin in 1 mM EGTA. Both polypeptides bind to F-actin in an ATP reversible fashion, and crosslink actin filaments. The purified polypeptides possess an actin-activated Mg2+-ATPase activity typical of brush border myosin-I. A polyclonal antiserum directed against the chicken intestinal 110-kDa polypeptide recognizes both rat liver polypeptides, whereas another serum recognizes the 130-kDa but not the 110-kDa rat liver polypeptide. Controlled proteolysis of the purified polypeptides with α-chymotrypsin indicates that the two polypeptides are distinct but related. Immunofluorescence microscopy on isolated hepatocytes shows distribution of myosin-I to be vesicular, distributed throughout the cytoplasm, but more concentrated near the nucleus. These data contribute new evidence by several functional criteria that multiple myosin-I molecules are present in higher organisms and may coexist in a single cell type. © 1993 Wiley-Liss, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970240306
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 142
    Electronic Resource
    Electronic Resource
    Expression of four myosin heavy chain isoforms with development in mouse uterus (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 358-368 
    Details
    ISSN: 0886-1544
    Keywords: smooth muscle ; smooth muscle myosin ; nonmuscle myosin ; myosin isoforms ; cellular myosin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In smooth muscle tissue, two or three isoforms of myosin heavy chain (MHC) have been reported (SM1, SM2, and/or NM). In mouse uterus tissue, four bands in the region of the MHC's can be resolved on high resolution SDS polyacrylamide gels. Western blots using smooth muscle (SM) MHC-specific and nonmuscle (NM) MHC-specific polyclonal antibodies show the upper two bands in the MHC region are SM isoforms, whereas the lower two bands are NM isoforms. One-dimensional peptide maps of these four bands show each to have a unique pattern of polypeptide fragments following α-chymotrypsin digestion. Developmental expression of myosin heavy chains (MHC) in mouse uterus, aorta, bladder, and stomach (6 ages, 10-150 days) was determined using tissue homogenates. In the uterus, both SM MHC's show an increase in relative content with increasing age, whereas the NM MHC's show a decrease. The mouse aorta shows a significant increase in the SM MHC's and a significant decrease in the NM MHC from day 10 to day 30, which is similar to data reported for the rat aorta. Whereas both the bladder and stomach contain relatively small amounts of NM MHC's (∼ 10% or less), these quantities do show decreases with development. The SM1:SM2 ratio for the uterus remains high (3.4 at 150 days) through development; the aorta, bladder, and stomach also start out high, but tend toward 1.0 in the 150-day animals. The presence of four MHC isoforms in the uterus with unique developmental regulation of expression is consistent with hypotheses of unique functional roles for these isoforms. © 1993 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970250406
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 143
    Electronic Resource
    Electronic Resource
    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993) 
    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.970260101
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 144
    Electronic Resource
    Electronic Resource
    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993) 
    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.970240401
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 145
    Electronic Resource
    Electronic Resource
    Microinjection of fluorescent brain tubulin reveals dynamic properties of cortical microtubules in living plant cells (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 205-213 
    Details
    ISSN: 0886-1544
    Keywords: microtubule dynamics ; cell morphogenesis ; Nitella pseudoflabelatta ; plant cytoskeleton ; Tradescantia virginiana ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fluorescent brain tubulin, injected into living cells of the green alga Nitella pseudoflabellata and the higher plant Tradescantia virginiana, incorporates into the cortical microtubules, allowing these structures to be observed. With confocal laser scanning microscopy, clear images of microtubules were recorded and changes in microtubule patterns documented. After injection, fluorescent lengths of microtubules appeared within a few minutes and their number and length increased rapidly to a “steady state” over the first 15 min. In many instances, fluorescent microtubules could still be detected several hours after injection. In the cells examined, microtubules are arranged as an array of separate units only occasionally displaying close association or accurate co-alignment with neighboring microtubules. In what we perceive to be the steady state condition, some microtubules remain relatively static, while others undergo rapid changes in length or small translocations. We also document what appears to be bidirectional microtubule elongation during postdepolymerization assembly. © 1993 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970240308
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 146
    Electronic Resource
    Electronic Resource
    Flagellar radial spoke: A model molecular genetic system for studying organelle assembly (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 24 (1993), S. 224-232 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970240403
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 147
    Electronic Resource
    Electronic Resource
    Site-directed antibodies to tubulin (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993), S. 1-6 
    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.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970260102
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 148
    Electronic Resource
    Electronic Resource
    Microtubule behavior in PC12 neurites: Variable results obtained with photobleach technology (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 345-357 
    Details
    ISSN: 0886-1544
    Keywords: fluorescent analogue cytochemistry ; cytoskeletal transport ; photobleach technology ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have examined the effects of various means of photobleaching on the recovery of fluorescene, movement, and morphology of the microtubules in the neurites of rhodamine-tubulin-injected PC12 cells. We find that, depending on power of and time of exposure to the bleaching beam, we can generate at least three different patterns of fluorescence recovery in regenerating PC12 neurites. If bleaching is performed with a relatively low-power beam for an extended period, fluorescence in polymer recovers very little after 1 hours. Under these conditions, however, tubulin immunostaining is seen extending through the bleach zone, and microtubules are present through the bleached zone in thin section electron micrographs. If bleaching is performed with a high-power laster, for 0.5-5 seconds, fluorescence recovery also is quite slow, but electron microscopic observations reveal that no microtubules extend through the bleached region of the neurite, and the uranyl acetate-stained cytoplasm appears more electron lucent than in the unbleached neurite. Finally, if bleaching is performed by very brief exposure to a high-intensity laser beam, resulting in an incomplete reduction of fluorescence intensity through the bleach zone, fluorescence recovery occurs within 20-30 minutes, and immunostained microtubules appear intact through the bleach zone; electron microscopy confirms that microtubules extended through the bleached zone of such neurites. In all three cases, movement of the bleach zone is observed in approximately half of the experimental neurites. These results indicate that highly variable microtubule behaviors can be obtained with photobleach technology, presumably due to different levels and pathways of photodamage generated by different bleach protocols. Nevertheless, it is clear that both turnover and movement of microtubules occur in FC12 neurites, and both are likely to be involved in neurite maintenance and growth. © 1993 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970250405
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 149
    Electronic Resource
    Electronic Resource
    Sarcomeric myosin heavy chain expressed in nonmuscle cells forms thick filaments in the presence of substoichiometric amounts of light chains (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993), S. 192-204 
    Details
    ISSN: 0886-1544
    Keywords: myofibrillogenesis ; myosin heavy chain ; myosin light chains ; transfection ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Central to the function of myosin is its ability to assemble into thick filaments which interact precisely and specifically with other myofibrillar proteins. We have established a novel experimental system for studying myofibrillogenesis using transient transfections of COS cells, a monkey kidney cell line. We have expressed both full-length rat α cardiac myosin heavy chain (MHC) and a truncated heavy meromyosin-like α MHC (sHMM) and shown that immunoreactive MHC proteins of the expected sizes were detected in lysates of transfected cells. Surprisingly, the full-length MHC formed large spindle-shaped structures throughout the cytoplasm of transfected cells as determined by immunofluorescence microscopy. The structures were not found in cells expressing the sHMM construct, indicating that their formation required an MHC rod. The spindle-shaped structures ranged in length from approximately 1 μm to over 20 μm in length and were birefringent suggesting that they are ordered arrays of thick filaments. This was confirmed by electron microscopic analysis of the transfected cells which revealed arrays of filamentous structures approximately 12 nm in diameter at their widest point. In addition, the vast majority of transfected MHC did not associate with the endogenous nonmuscle myosin light chains, demonstrating that myosin thick filaments can form in the absence of stoichiometric amounts of myosin light chains. © 1993 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970260303
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 150
    Electronic Resource
    Electronic Resource
    gCap39 is a nuclear and cytoplasmic protein (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993), S. 227-238 
    Details
    ISSN: 0886-1544
    Keywords: gelsolin ; actin binding proteins ; filament end capping ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: gCap39 is a newly identified member of the Ca2+- and polyphosphoinositidemodulated gelsolin family of actin binding proteins which is different from gelsolin in several important respects: it caps filament ends, it does not sever filaments, it binds reversibly to actin, it is phosphorylated in vivo, and it is also present in the nucleus. gCap39 and gelsolin coexist in a variety of cells. To better understand the roles of gCap39 and gelsolin, we have compared their relative amounts and intracellular distributions. We found that gCap39 is very abundant in macrophages (accounting for 0.6% of total macrophage proteins), and is present in 12-fold molar excess to gelsolin. Both proteins are highly induced during differentiation of the promyelocytic leukemia cell line into macrophages. gCap39 is less abundant in fibroblasts (0.04% total proteins) and is present in equal molar ratio to gelsolin. The two proteins are colocalized in the cytoplasm, but gCap39 is also found in the nucleus while gelsolin is not. Nuclear gCap39 redistributes throughout the cytoplasm during mitosis and is excluded from regions containing chromosomes. Our results demonstrate that gCap39 is a nuclear and cytoplasmic protein which has unique as well as common functions compared with gelsolin. © 1993 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970260306
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 151
    Electronic Resource
    Electronic Resource
    Effects of cytochalasin and colcemid on cortical flow in coelomocytes (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993), S. 262-273 
    Details
    ISSN: 0886-1544
    Keywords: cortical flow ; coelomocytes ; cytoskeleton ; video enhanced microscopy ; cytochalasin ; colcemid ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Sea urchin coelomocytes naturally flatten on a substratum into a discoid morphology and display striking, centripetally directed cortical flow along the radii of the cell when viewed with time lapse, video enhanced microscopy. The rate of cortical flow averaged 4.5 μm/min in the peripheral most 10 μm of cytoplasm but slows considerably in the perinuclear region. Cytochalasin B causes: (1) the flow to stop, (2) the buildup of an actin filament-rich peripheral ridge of cytoskeletal material, (3) the centrifugal dissolution of a portion of the actin cytoskeleton, and (4) the contraction of other portions of the cytoskeleton into foci. Cytochalasin D (CD), on the other hand, causes the flowing actin meshwork to become severed from the edge of the cell and allows it to be drawn at least part way in towards the nucleus. A smaller peripheral ridge of actin filament buildup is also seen with CD. Colcemid induces another striking change in the cytoskeleton. The centripetal progression of the actin is not stopped by colcemid, but shortly after leaving the periphery of the cell, the linear elements within the flow become reoriented into arcs. The long axis of the arcs is roughly parallel with the cell's edge. The effects of all three drugs are reversible. The results are discussed in light of other systems and potential mechanisms for cortical flow. © 1993 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970260309
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 152
    Electronic Resource
    Electronic Resource
    Masthead (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993) 
    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.970260401
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 153
    Electronic Resource
    Electronic Resource
    Unambiguous classification of microtubule-ends in vitro: Dynamic properties of the plus- and minus-ends (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993), S. 282-290 
    Details
    ISSN: 0886-1544
    Keywords: DIC microscopy ; dynamic instability ; kinesin ; microspheres ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: To understand the mechanism of dynamic instability of microtubule growth and shortening, one needs a means of reliably determining the polarity of the microtubules under investigation. Sea urchin sperm-tail axonemal fragments nucleate the growth of both plus-ended and minus-ended microtubules, but their polarity is not apparent by video-enhanced DIC microscopy. The polarity of a microtubule is usually assessed by observing differences between the rates and lengths of growth and shortening excursions of the two ends. In practice, though, a significant fraction of the population of microtubules displays characteristics intermediate between the average characteristics of either end, thereby escaping classification. Excluding these “intermediate” microtubules from the measured populations introduces bias into the understanding of microtubule dynamic instability. We circumvent this problem by making use of the plus-end directed movement of the microtubule-dependent molecular motor kinesin to determine the polarity of any given microtubule unambiguously. Carboxylated-microspheres coated with kinesin, which are clearly visible by DIC microscopy, were used to determine the polarity of a microtubule. The dynamics were then observed. Kinesin was found to have no marked effect on dynamic instability. By this technique, we show that the distributions of properties that describe microtubule dynamic instability (rates and lengths of growth and shortening as well as frequencies of interconversion between these phases) of plus-ends overlap to a significant extent with those of minus-ends. It is this overlap that obscures the usual classification of the ends. Therefore, models describing microtubule dynamic instability need to incorporate the broad and overlapping range of properties of the two ends. © 1993 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970260403
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 154
    Electronic Resource
    Electronic Resource
    Neurofilaments move apart freely when released from the circumferential constraint of the axonal plasma membrane (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993), S. 313-324 
    Details
    ISSN: 0886-1544
    Keywords: neurofilament ; plasma membrane ; axon ; squid giant axon ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Squid giant axons were used to obtain axonal cytoskeletons that had been separated from the confines of their plasma membranes. To remove the plasma membrane, axoplasm was extruded from the giant axon directly into an artificial axoplasm solution (AAS). This procedure produces a smooth axoplasmic cylinder in which neurofilaments (NFs) are the most prevalent cytological elements. The NFs scatter light strongly and thus dark-field light microscopy can be used to quantify the volume occupied by these polymers. Measurements of the widths of the dark-field images of the axoplasmic cylinders showed that the cross-sectional area of the NF population increased by 60-110% (n = 8) between 1-100 min after plasma membrane removal, and then continued to increase more slowly for many hours. After 1,000 min, the cross-sectional area was 75-160% (n = 8) larger than at 1 min. These light microscopic measurements of axoplasm suggest that the NF population disperses to occupy a continuously increasing volume after removal of the plasma membrane and immersion in AAS. This inference was confirmed by quantitative ultrastructural studies of NFs in axoplasmic cross-sections, which demonstrated that the spacing between the NFs increased between 1-1,000 min after plasma membrane removal. Comparison of the NF density distribution after 1,000 min with a theoretical distribution calculated using the Poisson theorem indicated that the NFs dispersed randomly. These studies on NFs in isolated axoplasm suggest that ordinary thermal forces of Brownian motion are sufficient to move axonal NFs apart independently and thereby to disperse them. We propose that, in the intact axon, the dispersive movements of the NFs spread the NF cytoskeleton radially and expansively to fill out the cylindrical space contained by the axonal plasma membrane and its surrounding connective tissue elements. © 1993 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970260406
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 155
    Electronic Resource
    Electronic Resource
    Three-dimensional dynamics of pseudopod formation and the regulation of turning during the motility cycle of Dictyostelium (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 1-12 
    Details
    ISSN: 0886-1544
    Keywords: pseudopod extension ; amoebae ; uropod retraction ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Employing a newly developed computer-assisted system for visualizing and quantitating cell motility in three dimensions, we have examined the 3-dimensional changes in cell shape and the dynamics of pseuodopod extension during translocation of Dictyostelium amoebae. Amoebae exhibit a 3-dimensional behavior cycle with an average period of 1.5 min. The cycle includes a transient pseudopod extension phase in the x, y axis followed by a z-axis expansion phase. Anterior pseudopod extension in the x, y axis is accompanied by a decrease in height, not by uropod retraction. The increase in height is accompanied by uropod retraction. In the pseudopod extension phase in the x, y axes, pseudopods form either anteriorly or laterally, and either on or above the substratum. Pseudopods which initially form on the substratum in almost all cases continue to expand as the anterior end of the cell. In the case of lateral pseuodopods, anteriorization leads to a turn. Approximately half of anterior pseudopod and two-thirds of lateral pseudopods which initially form above the substratum are retracted. These results suggest that pseudopod-substratum interaction plays a fundamental role in the regulation of directionality and turning in the translocation phase of the 3-dimensional behavior cycle. © 1994 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970270102
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 156
    Electronic Resource
    Electronic Resource
    FRAP analysis of the stability of the microtubule population along the neurites of chick sensory neurons (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 25 (1993), S. 59-72 
    Details
    ISSN: 0886-1544
    Keywords: microtubule dynamics ; photobleaching ; neurite elongation ; microtubule stability ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In order to study microtubule turnover in elongating neurites, chick embryo sensory neurons were microinjected with x-rhodamine tubulin, and after 6-12 hours, short segments along chosen neurites were photobleached at multiple sites. Previous studies [Lim et al., 1989; 1990] indicated that recovery of fluorescence (FRAP) in neurites occurs by the dynamic turnover of stationary microtubules. In all cases, distal bleached zones recovered fluorescence faster than bleached zones more proximally located along the same neurites. Bleached zones at growth cones completely recovered in 30-40 minutes, while bleached zones located more proximally usually recovered in 50-120 minutes. In the most proximal regions of long neurites, recovery of fluorescence was often incomplete, indicating that a significant fraction of the microtubules in these regions were very stable. These studies indicate that there are differences in microtubule stability along the lenght of growing neurites. These differences may arise from the combined effects of (1) modifications that stabilize and lengthen microtubules in maturing neurites and (2) the dynamic instability of the distally oriented microtubule plus ends. © 1993 Wiley-Liss, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970250108
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 157
    Electronic Resource
    Electronic Resource
    In vitro functional characterization of bacterially expressed human fibroblast tropomyosin isoforms and their chimeric mutants (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993), S. 248-261 
    Details
    ISSN: 0886-1544
    Keywords: human fibroblast tropomyosins ; actin-binding protein ; caldesmon ; actin-tropomyosin-activated HMM ATPase ; motility ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: At least eight tropomyosin isoforms (hTM1, hTM2, hTM3, hTM4, hTM5, hTM5a, hTM5b, and hTMsmα) are expressed from four distinct genes in human fibroblasts. In order to elucidate isoform properties, we have subcloned hTM3 and hTM5 full-length cDNAs, as well as their chimeric cDNAs into the bacterial expression pET8C system. Bacterially expressed tropomyosin isoforms (called PEThTM3, PEThTM5. PEThTM5/3, and PEThTM3/5) were purified and characterized. Under optimal binding conditions, the binding of PEThTM5 isoform to F-actin was stronger than the PEThTM3 isoform. However, analysis of actin-binding by the McGhee and von Hippel equation revealed that PEThTM3 exhibits higher cooperativity in binding than PEThTM5 does. Furthermore, the chimera PEThTM5/3 which possessed the N-terminal fragment of hTM5 fused to the C-terminal fragment of hTM3 had even stronger actin binding ability. The reverse chimera PEThTM3/5 which possessed the N-terminal fragment of hTM3 fused to the C-terminal fragment of hTM5 demonstrated greatly reduced affinity to actin filaments. In addition, both chimeras had different KCl requirements for optimal binding to F-actin than their parental tropomyosins. A bacterially made C-terminal fragment of human fibroblast caldesmon (PETCaD39) and native chicken gizzard caldesmon were both able to enhance the actin-binding of these bacterially expressed tropomyosins. However, PETCaD39′s enhancement of binding to F-actin was greater for PEThTM5 than PEThTM3. Under 30 mM KCl and 4 mM MgCl2, the low Mr isoform PEThTM5 appeared to be able to amplify the actin-activated HMM ATPase activity by 4.7 fold, while the high Mr isoform PEThTM3 stimulated the activity only 1.5 fold. The higher enhancement of ATPase activity by PEThTM5 than by PEThTM3 suggested that the low Mr isoform hTM5 may be more involved in modulating nonmuscle cell motility than hTM3. These results further suggested that different isoforms of tropomyosin might have finite differences in their specific functions (e.g., cytoskeletal vs. motile) inside the cell. © 1993 Wiley-Liss, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970260308
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 158
    Electronic Resource
    Electronic Resource
    Contractile protein dynamics of myofibrils in paired adult rat cardiomyocytes (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993), S. 301-312 
    Details
    ISSN: 0886-1544
    Keywords: intercated discs ; microinjection ; actin ; alpha-actinin ; vinculin ; myosin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The purpose of this study was to determine how quickly contractile proteins are incorporated into the myofibrils of freshly isolated cardiomyocytes and to determine whether there are regions of the cells that are more dynamic than others in their ability to incorporate the proteins. Paired cardiomyocytes joined at intercalated discs and single cells were isolated from adult rats, and microinjected 3 hours later with fluorescently labeied actin, alpha-actinin, myosin light chains, and vinculin. The cells were fixed and permeabilized at various period, 5 seconds and longer, after microinjection. Actin became incorporated throughout the I-Bands in as short a time as 5 seconds. The free edges of the cells, which were formerly intercalated discs, exhibited concentrations of actin greater than that incorporated in the I-Bands. This extra concentration of actin was not detected, however, at intact intercalated discs connecting paired cells. Alpha-actinin was incorporated immediately into Z-Bands and intercalated discs. Vinculin, also, was localized at the Z-Bands and at intercalated discs, but in contrast to alpha-actinin, there was a higher concentration of vinculin in the region of the intact intercalated discs. Both alpha-actinin and vinculin were concentrated at the free ends of the cells that were formerly parts of intercalated discs. Myosin light chains were observed to incorporate into the A-Bands in periods as short as 5 seconds. These results suggest that the myofibrils of adult cardiomyocytes may be capable of rapid isoform transitions along the length of the myofibrils. The rapid accumulation of fluorescent actin, alpha-actinin, and vinculin in membrane sites that were previously parts of intercalated discs, may reflect the response to locomotory activity that is initiated in these areas as cells spread in culture. A similar response after an injury in the intact heart could allow repair to occur. © 1993 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970260405
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 159
    Electronic Resource
    Electronic Resource
    Role of phosphorylation in keratin and vimentin filament integrity in cultured thyroid epithelial cells (1993)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 26 (1993), S. 325-339 
    Details
    ISSN: 0886-1544
    Keywords: calyculin A ; phosphatase 1/2A ; intermediate filament disruption ; actomyosin contraction ; C-kinase ; intermediate filament protein kinase ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cytokeratin and vimentin intermediate filaments (IFs) possess relatively stable polymeric properties which can be affected by phosphorylation. The present study, using cultures of thyroid epithelial cells, shows by indirect immunofluorescence that these cells contain both keratin tonofilament and vimentin IF complexes. Immunoblots of Triton X-100 insoluble cytoskeletal fractions show vimentin, and ∼52 kDa type II and 40/38 kDa type I keratins. Under “basal” conditions, following prelabeling of cells with [32PO4], vimentin is not significantly phosphorylated, while both type II and I keratins are phosphorylated. Treatment of cells for 20 min with 1 mM dbcAMP or 0.4 μM 12-O-tetradecanoylphorbol-13-acetate (TPA), to stimulate protein kinase A and C, respectively, has no effect on either the phosphorylation state or cytoplasmic filament integrity of vimentin. However, while dbcAMP also does not affect keratin filaments, TPA increases both type II and I phosphorylation ∼3-fold, and concomitantly disrupts tonofilament complexes associated with the nucleus, cytoplasm, and desmosomes. TPA-treated cells also show dramatic shape changes and protrusive activity. Tryptic peptide mappings show phosphorylations of at least 6 and ∼2 additional sites for type II and I keratins, respectively, vs. [32P]-peptides from control cells. Treatment of [32PO4]-labeled cells with 0.4 μM calyculin A to inhibit types 1 and 2A phosphatase activity causes hyperphosphorylation of both vimentin and keratin, disruption of IF complexes, and actomyosin/cell contraction within 20 min. Quantitatively, ∼50% of the type II/I keratin hyperphosphorylations are at some sites apparently also phosphorylated after TPA treatment. Thus, in these cells, IFs are specifically and differentially affected and regulated by the activity of several kinases. © 1993 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970260407
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 160
    Electronic Resource
    Electronic Resource
    Microtubule converging centers and reorganization of the interphase cytoskeleton and the mitotic spindle in higher plant Haemanthus (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 219-233 
    Details
    ISSN: 0886-1544
    Keywords: microtubules ; mitosis ; cytoskeleton reorganization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We analyzed the distribution and orientation of transitory microtubule structures, microtubule converging centers, during interphase and mitosis in endosperm of the higher plant Haemanthus. In interphase the pointed tips of microtubule converging centers are associated with the nuclear envelope. Their orientation gradually reverses during prophase, and the tips tend to point away from the nucleus. From prometaphase through early telophase, microtubule converging centers are present predominantly in the cytoplasm at the polar region. They are either “free” or associated with chromosomes or microtubule bundles. In late telophase, pointed tips of microtubule converging centers are again associated with the reconstructed nuclear envelope and, additionally, they often appear in the phragmoplast area. The orientation of microtubule converging centers seems to be directly correlated to the previously determined microtubule polarity, with the converging tip being minus and the diverging one, plus.Elevated temperature (35°-37°) enhances the number of microtubule converging centers in the cytoplasm and at the nuclear envelope. This is especially pronounced during the telophase-interphase transition and in some interphase cells, indicating temperature and stage dependence.Our data imply that microtubule converging centers bind together MT minus ends and, thus, control the predominant direction of elongation and shortening of microtubule arrays. We argue that these configurations are instrumental during the reorganization of interphase cytoskeleton and mitotic spindle in Haemanthus endosperm. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970270304
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 161
    Electronic Resource
    Electronic Resource
    ATP-induced sliding of microtubules on tracks of 22S dynein molecules aligned with the same polarity (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 180-191 
    Details
    ISSN: 0886-1544
    Keywords: sliding movement ; 22S dynein ; Tetrahymena cilia ; dynein-track ; singlet microtubule ; ATP ; polarity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Chlamydomonas and Tetrahymena axonemal dyneins have previously been found to bind to porcine brain microtubules to produce a microtubule-dynein complex. At appropriate microtubule:dynein concentration, microtubules in the complex became covered to saturation by dynein arms of the same polarity and at a spacing of 24 nm [Haimo et al., 1979; Haimo and Fenton, 1988; Haimo, 1989; Porter and Johnson, 1983a].In the present study, two different types of microtubule-dynein complexes (α-and β-complexes) were prepared from Tetrahymena ciliary 22S dynein and porcine brain tubulin. The characteristics of the adenosine triphosphate (ATP)-induced extrusion of microtubules from these complexes were analyzed, as a simple and direct in vitro assay for the ATP-induced extrusion of single microtubules. The α-complex prepared by adding dynein to microtubules showed an interrupted sliding movement, which would stop and start several times following the addition of ATP. In the β-complex, prepared by adding dynein bound to DEAE-tubulin to pre-assembled microtubules, microtubules became covered with dynein molecules whose orientation and binding were uniform with respect to microtubule polarity. The microtubules in the β-complex extruded at 12 μm/second following the addition of ATP. Dark-field and electron microscopy indicated that the extruded microtubules had undergone sliding on a dynein-track that had become detached from the complexes and had been absorbed onto the surface of the glass slide. At higher light intensity under a dark-field microscope, the dynein-track was seen to be composed of rows of dynein molecules arranged densely. The orientation of dynein molecules in rows appeared to be uniform considering the images of bound dynein in the β-complex under electron microscope. The higher sliding velocity of the microtubules on these dynein-tracks compared to that seen on slides coated at random with dynein [Vale and Toyoshima, 1988, 1989], may be due to more efficient force generation by this dense arrangement of dynein molecules with the same polarity on the tracks. © 1994 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970270209
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 162
    Electronic Resource
    Electronic Resource
    Role of cAMP in the reactivation of demembranated ram spermatozoa (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 206-218 
    Details
    ISSN: 0886-1544
    Keywords: sperm motility ; sperm maturation ; flagella ; protein kinases ; protein kinase inhibitor ; cGMP ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Ejaculated ram sperm were demembranated with Triton X-100, separated from the detergent-soluble matrix, and reactivated [San Agustin and Witman (1993): Cell Motil. Cytoskeleton 24:264-273]. The percent motility of models prepared from freshly washed sperm was comparable to that of the washed sample before demembranation, regardless of whether cAMP was included in the reactivation medium. However, demembranated models derived from aging or metabolically inhibited sperm exhibited a lower percent reactivation and required cAMP to attain the level of motility of freshly washed sperm. Cyclic AMP was ∼100 times more effective than cGMP. The requirement for cAMP could be bypassed by addition of porcine heart cAMP-dependent protein kinase (PKA) catalytic subunit to the reactivation medium, demonstrating that cAMP was acting via PKA. The cAMP stimulation of reactivation was not affected by inclusion of the PKA inhibitor PKI(5-24) in the reactivation medium, but was decreased when the models were preincubated with PKI(5-24) prior to reactivation. The cytosol-free models retained 〉90% of the sperm PKA activity; therefore, the PKA appears to be anchored to internal sperm structures. This PKA could not be extracted by cAMP or Triton X-100 alone, but only by cAMP and Triton X-100 in combination. We conclude that cAMP-dependent protein phosphorylation is critical for sperm motility, but that the essential protein phosphate sites turn over slowly under our reactivation conditions, so that the cAMP requirement is apparent only in models prepared from sperm having a low internal ATP or cAMP content. Interestingly, reactivation was rapidly blocked by the peptide arg-lys-arg-ala-arg-lys-glu, which has been reported to be a selective inhibitor of cGMP-dependent protein kinase. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970270303
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 163
    Electronic Resource
    Electronic Resource
    Coordinated expression of five tropomyosin isoforms and β-actin in astrocytes treated with dibutyryl cAMP and cytochalasin D (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994), S. 303-316 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeleton ; cell culture ; gene expression ; Northern blot ; serum-induction ; rat ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cytochalasin D and dBcAMP cause cultured astrocytes to change from flat cells to retrated process-bearing cells. F-actin was present throughout cells stimulated with dBcAMP for 16 h, whereas cytochalasin D caused F-actin to form massive aggregates at the tips of the cell processes. The two drugs differently regulated the expression of both β-actin and tropomyosin genes in astrocytes cultured in the presence or absence of serum: dBcAMP caused down-regulation and cytochalasin D caused up-regulation. Northern blot analyses indicated that: (1) serum deprivation halved the concentration of all tropomyosin transcripts (TM-1, TM-2, TM-4, TMBr-1, TMBr-2). Serum induced TM-4 via transcriptional activation, independent of protein synthesis, (2) dBcAMP induced down-regulation of β-actin (-50%) and tropomyosin transcripts (-35 to 52%) even in the presence of serum. The concentration of profilin mRNA decreased in dBcAMP-reactive astrocytes (-46%). The decrease in β-actin mRNA concentration was not blocked by cycloheximide, whereas down-regulation of tropomyosin transcripts was completely reversed when protein synthesis was inhibited, and (3) cytochalasin D induced an increase in the concentration of tropomyosin transcripts (+ 69 to 185%) which was cumulative with serum stimulation. Cytochalasin D induction of both β-actin and TM-4 operated through transcriptional activation, independent of protein synthesis.The production of all tropomyosin transcripts examined here were strictly coordinated with β-actin expression in serum-, dBcAMP- and cytochalasin D-treated astrocytes. This indicates that the differential expression of tropomyosin isoforms occurring during astrocyte maturation is due to more complex regulation than that involved in serum- or cAMP-stimulated astrocytes. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970280404
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 164
    Electronic Resource
    Electronic Resource
    Announcement (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994), S. 360-360 
    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.970280410
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 165
    Electronic Resource
    Electronic Resource
    Regulation of the Ascaris major sperm protein (MSP) cytoskeleton by intracellular pH (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 193-205 
    Details
    ISSN: 0886-1544
    Keywords: amoeboid motility ; fluorescence ratio imaging ; BCECF ; nematodes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The development and locomotion of the amoeboid sperm of the nematode, Ascaris suum, depend on precise control of the assembly of their unique major sperm protein (MSP) filament system. We used fluorescence ratio imaging of cells loaded with BCECF to show that intracellular pH (pHi) is involved in controlling MSP polymerization in vivo. Spermatogenesis is marked by a cycle of MSP assembly-disassembly-reassembly that coincides with changes in pHi. In spermatocytes, which contain MSP in paracrystalline fibrous bodies, pHi was 6.8, 0.6 units higher than in spermatids, which disassemble the fibrous bodies and contain no assemblies of MSP filaments. Activation of spermatids to complete development resulted in rapid increase in pHi to 6.4 and reappearance of filaments. Treatment of spermatocytes with weak acids caused the fibrous bodies to disassemble whereas incubation of spermatids in weak bases induced MSP assembly. The MSP filaments in spermatozoa are organized into fiber complexes that flow continuously rearward from the leading edge of the pseudopod. These cells established a pseudopodial pH gradient with pHi 0.15 units higher at the leading edge, where fiber complexes assemble, than at the base of the pseudopod, where disassembly occurs. Acidification of these cells caused the MSP cytoskeleton to disassemble and abolished the pH gradient. Acid removal resulted in reassembly of the cytoskeleton, re-establishment of the pH gradient, and re-initiation of motility. MSP assembly in sperm undergoing normal development and motility and in cells responding to chemical manipulation of pHi occurs preferentially at membranes. Thus, we propose that filament assembly in sperm is controlled by pH-sensitive MSP-membrane interaction. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970270302
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 166
    Electronic Resource
    Electronic Resource
    Antisense MAP-2 oligonucleotides induce changes in microtubule assembly and neuritic elongation in pre-existing neurites of rat cortical neurons (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 234-247 
    Details
    ISSN: 0886-1544
    Keywords: microtubule-associated protein 2 ; neurons ; microtubule-associated proteins ; cytoskeleton ; dendrites ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Microtubule-associated protein 2 (MAP-2) is an abundant component of the cytoskeleton present in dendrites and cell bodies of neurons of the CNS. To examine the biological function of MAP-2, two MAP-2 antisense (AS) oligonucleotides complementary to the 5′ region of the rat MAP-2 cDNA were added to rat primary embryonic day 17-18 (E17-18) cultured cortical neurons 24 h after plating and neurite outgrowth and morphology studied. The treatment of primary cortical cultures with either of the two MAP-2 AS oligonucleotides resulted in decreased MAP-2 and reduction in the number of neuritic processes relative to the control or MAP-2 sense-treated cultures. By immunostaining and light microscopy the AS-treated neurons appeared smaller, more rounded, and less intensely stained for MAP-2 than the untreated or the MAP-2 sense-treated cultures. By electron microscopy disorganized microtubules and a reduction in the number of microtubules within neurites of the AS-treated cultures were observed. We conclude that MAP-2 continues to be required for microtubule spacing and stability within neurites once they have formed. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970270305
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 167
    Electronic Resource
    Electronic Resource
    Cellular infrared detector appears to be contained in the centrosome (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 262-271 
    Details
    ISSN: 0886-1544
    Keywords: 3T3 cells ; cell motility ; infrared ; phototaxis ; centrosome ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Previous experiments have suggested that 3T3 cells were able to extend pseudopodia toward latex particles up to 60 μm away from the cell body if the particles were irradiated by an infrared beam in the range of 700-900 nm [Albrecht-Buehler, 1991: J. Cell Biol. 114:493-502]. The present article reports that this response of cells to infrared light can be inhibited if the cell center is simultaneously irradiated with a beam of the same light. In marked contrast, the cells responded normally to the presence of infrared light scattering particles if the second beam irradiated other parts of the cell body. The results imply that the cellular mechanism of infrared detection is located at the cell center. The infrared sensing mechanism remains intact in enucleated cells and in cells which were incubated in monensin to vesiculate their Golgi apparatus and inhibit their Golgi functions. Accordingly, it is proposed that the centrosome which contains the centrioles is the only remaining candidate in the cell center for a cellular detection device for the direction of infrared signal sources. The results support an earlier suggestion that centrioles may be such detection devices [Albrecht-Buehler, 1981: Cell Motil. Cytoskeleton 1:237-245]. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970270307
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 168
    Electronic Resource
    Electronic Resource
    Regulation and evolution of the single alpha-tubulin gene of the ciliate Tetrahymena thermophila (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 272-283 
    Details
    ISSN: 0886-1544
    Keywords: cell cycle ; transcription ; mRNA decay ; autoregulation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The single alpha-tubulin gene of Tetrahymena thermophila was isolated from a genomic library and shown to encode a single protein. Comparisons of the rates of evolution of this gene with other alpha-tubulin sequences revealed that it belongs to a group of more evolutionarily constrained alpha-tubulin proteins in animals, plants, and protozoans versus the group of more rapidly evolving fungal and variant animal alpha-tubulins. The single alpha-tubulin of Tetrahymena must be used in a variety of microtubule structures, and we suggest that equivalently conserved alpha-tubulins in other organisms are evolutionarily constrained because they, too, are multifunctional. Reduced constraints on fungal tubulins are consistent with their simpler microtubule systems. The animal variant alpha-tubulins may also have diverged because of fewer functional requirements or they could be examples of specialized tubulins. To analyze the role of tubulin gene expression in regulation of the complex microtubule system of Tetrahymena, alpha-tubulin mRNA amounts were examined in a number of cell states. Message levels increased in growing versus starved cells and also during early stages of conjugation. These changes were correlated with increases in transcription rates. Additionally, alpha-tubulin mRNA levels oscillate in a cell cycle dependent fashion caused by changes in both transcription and decay rates. Therefore, as in other organisms, Tetrahymena adjusts alpha-tubulin message amounts via message decay. However the complex control of alpha-tubulin mRNA during the Tetrahymena life cycle involves regulation of both decay and transcription rates. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970270308
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 169
    Electronic Resource
    Electronic Resource
    Physical model of axonemal splitting (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 287-298 
    Details
    ISSN: 0886-1544
    Keywords: cilium ; flagellum ; motility ; microtubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A physical model developed to explain microtubule sliding patterns in the trypsintreated ciliary axoneme has been extended to investigate the generation of bending moments by microtubules sliding in an axoneme in which the dublets are anchored at one end. With sliding restricted, a bending moment is developed by the polarized shearing interaction between neighbouring doublets, effected by the activity of dynein arms on doublet N pushing N + 1 in a tipward ( + ) direction. In arrested axonemes in which arms on several contiguous doublets are active, the bending moment causes splitting of the 9 + 2 microtubule array into two or more sets of doublets. In the absence of special constraints, splitting depends only on breaking the circumferential interdoublet links most distorted by the bending moment. The analysis, which permits assignment of arm activity to specific microtubules in each of the observed patterns of splitting, indicates that the axoneme will split between doublet N and N + 1 if arms on doublet N are inactive and arms on either N + 1 or N-1 are active. To produce the observed major splits, dynein arms on the microtubules of roughly one-half of the axoneme are predicted to be active, in a manner consistent with the switch-point hypothesis of ciliary motion. Electron microscopic examination indicates that virtually every set of doublets in the split axonemes retains its cylindrical form. Maintenance of cylindrical symmetry can be ascribed to the mechanical properties of the unbroken links, which may resist both tensile and compressive stress, and to active dynein arms. © 1994 Wiley-Liss, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970270402
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 170
    Electronic Resource
    Electronic Resource
    Functional analysis of a cardiac myosin rod in Dictyostelium discoideum (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 313-326 
    Details
    ISSN: 0886-1544
    Keywords: myosin II ; cardiac ; sarcomeric ; cytoplasmic myosin ; LMM ; Dd ; heterologous expression ; ConA ; receptor capping ; aggregation ; filament assembly region ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Manipulation of the single conventional myosin heavy chain (mhc) gene in Dictyostelium discoideum (Dd) has delineated an essential role for the filament-forming, or light meromyosin (LMM) domain of the myosin molecule in cyto-kinesis, development, and in the capping of cell surface receptors (see Spudich: Cell Regulation 1:1-11, 1989; Egelhoff et al.: Journal of Cell Biology, 112:677-688, 1991a). In order to assess the functional relationship between sarcomeric and cytoplasmic myosins, a chimeric gene encoding the Dd myosin head and subfragment 2 fused to rat β cardiac LMM was transfected into both wild-type and Dd mhc null cells. Chimeric myosin was organized into dense cortical patches in the cytoplasm of both wild-type and Dd mhc null cells. Although null cells expressing chimeric mhc at ∼10% of Dd mhc levels were unable to grow in shaking suspension or to complete development, chimeric myosin was able to rescue capping of cell surface receptors, to associate with filamentous actin, and to localize to the correct subcellular position during aggregation. Deletion of 29 amino acids in the rod corresponding to a previously defined filament assembly competent region eliminated the cortical patches and the posterior localization during chemotaxis. Taken together, these observations suggest that sarcomeric and cytoplasmic myosin rods are functionally interchangeable in several aspects of nonmuscle motility. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970270404
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 171
    Electronic Resource
    Electronic Resource
    Cell motility and the cytoskeleton video supplement 4 (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 27 (1994), S. 361-372 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970270408
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 172
    Electronic Resource
    Electronic Resource
    Masthead (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994) 
    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.970280101
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 173
    Electronic Resource
    Electronic Resource
    Effects of 6-dimethylaminopurine on the length of the cell cycle and on the state of phosphorylation of putative intermediate filament proteins in sea urchin embryos (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 131-140 
    Details
    ISSN: 0886-1544
    Keywords: intermediate filaments ; phosphorylation ; sea urchin embryos ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effects of 6-dimethylaminopurine (6-DMAP) on the length of the cell cycle and on the state of phosphorylation of a putative intermediate filament protein, p117, have been studied in sea urchin embryos. Embryos were transferred into sea water containing 600 μM 6-DMAP at 0.5, 2 or 5 min after insemination, and incubated for 30 or 90 min. The effects of 6-DMAP on cell cycle length were studied by determining the time required for completion of mitosis upon return of the embryos in normal sea water. In all instances, except for the embryos transferred 0.5 min after insemination (AI) and incubated for 30 min, the duration of the M phase was shortened compared to controls, being faster in the embryos incubated for 90 minutes compared to the 30 min incubation period. However, embryos transferred 0.5 min AI have a longer M-phase than those transferred 2 minutes or later after fertilization, suggesting that between 0.5 and 2 min after fertilization, critical phosphorylating events occur which affect the commitment of the cells to enter M-phase.To study the pattern of p117 phosphorylation during the cell cycle, the eggs were transferred 2 minutes after fertilization in presence of 600 μM 6-DMAP and with 200 μCi/ml of 32P-orthophosphate. Analyses of 32P-labelled proteins after exposure of SDS-PAGE gels and their corresponding blots suggested that phosphorylation of p117 greatly increases at the time of pronuclear fusion, and then declines slightly at prophase-metaphase. This decrease is markedly enhanced when the cells are treated with 6-DMAP during metaphase in order to induce a premature breakdown of the mitotic apparatus. A causal link is suggested between the level of phosphorylation of p117 and its state of assembly. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970290205
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 174
    Electronic Resource
    Electronic Resource
    Kinesin-related polypeptide is associated with vesicles from Corylus avellana pollen (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 155-166 
    Details
    ISSN: 0886-1544
    Keywords: Golgi vesicles ; pollen ; pollen tube ; microtubules ; kinesin-related protein ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A 100-kDa polypeptide with microtubule-interacting properties was identified in a Golgi vesicle-enriched fraction from Corylus avellana pollen. The k71s23 antibody (directed to the kinesin heavy chain from bovine brain) [Tiezzi et al., 1992: Cell Motil. Cytoskeleton 21:132-137] localized the polypeptide on the external surface of membrane-bounded organelles. Some 100-kDa-containing vesicles co-pelleted with microtubules (polymerized from purified bovine brain tubulin) either in presence or absence of 5 mM AMPPNP, but they could be released by 10 mM ATP or 0.5 M KCl. The pollen microtubule-interacting protein, salt-extracted from membranes and partially purified by gel filtration, exhibited an ATPase activity (16.2 nmolPi/mg/min) which could be stimulated about 2-fold (32.5 nmolPi/mg/min) by addition of bovine brain microtubules. We suppose that the 100-kDa polypeptide is part of a molecular complex showing properties of the kinesin class. © 1994 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970290207
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 175
    Electronic Resource
    Electronic Resource
    Assembly and bundling of marginal band microtubule protein: Role of tau (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 57-71 
    Details
    ISSN: 0886-1544
    Keywords: microtubule bundling ; cytoskeleton ; tau ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Microtubule protein extracted from dogfish erythrocyte cytoskeletons by disassembly of marginal bands at low temperature formed linear microtubule (MT) bundles upon reassembly at 22°C. The bundles, which were readily visible by video-enhanced phase contrast or DIC microscopy, increased in length and thickness with time. At steady state after 1 hour, most bundles were 6-11 μm in length and 2-5 MTs in thickness. No inter-MT cross-bridges were visible by negative staining. The bundles exhibited mechanical stability in flow as well as flexibility, in this respect resembling native marginal bands. As analyzed by SDS-PAGE and immunoblotting, our standard extraction conditions yielded MT protein preparations and bundles containing tau protein but not high molecular weight MAPs such as MAP-2 or syncolin. In addition, late fractions of MT protein obtained by gel filtration were devoid of high molecular weight proteins but still produced MT bundles. The marginal band tau was salt-extractable and heat-stable, bound antibodies to mammalian brain tau, and formed aggregates upon desalting. Antibodies to tau blocked MT assembly, but both assembly and bundling occurred in the presence of antibodies to actin or syncolin. The MTs were “unbundled” by subtilisin or by high salt (0.5-1 M KCl or NaCl), consistent with tau involvement in bundling. High salt extracts retained bundling activity, and salt-induced unbundling was reversible with desalting. However, reversibility was observed only after salt-induced MT disassembly had occurred. Reconstitution experiments showed that addition of marginal band tau to preassembled MTs did not produce bundles, whereas tau presence during MT reassembly did yield bundles. Thus, in this system, tau appears to play a role in both MT assembly and bundling, serving in the latter function as a coassembly factor. © 1994 Wiley-Liss, Inc.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970290106
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 176
    Electronic Resource
    Electronic Resource
    Fluorescence studies of spectrin and its subunits (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 72-81 
    Details
    ISSN: 0886-1544
    Keywords: spectrin ; intrinsic fluorescence ; spectrin elasticity ; fluorescence quenching ; spectrin α chain ; spectrin β chain ; membrane skeleton ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: To better understand the solution structure of spectrin, the environments of its tryptophan residues have been examined by fluorescence spectroscopy. The spectra and the extent of quenching by several quenching agents have been determined for intact spectrin and its α and β subunits. The arsenal of quenchers used in the study represented both hydrophilic and hydrophobic species including anionic, cationic and neutral compounds. Effects on spectrin fluorescence of ethanol and ionic strength, which extend and/or rigidify spectrin, and of glycerol, which is commonly used in electron microscopy of the protein, have also been assessed in the presence and absence of quenchers. Most of the tryptophans of spectrin are either internally quenched or are sequestered, hindering the approach of hydrophilic quenching agents. Both the spectral shape and the extent of quenching by acrylamide indicate that some tryptophans of the β subunit are slightly more exposed in the isolated chain than in the dimer. Similar effects on spectra and on quenching of the intact dimer and of the isolated β chain are seen when the ionic strength is reduced. Ethanol and glycerol reduce spectrin tryptophan accessibility to 2-p-toluidinyl napthalene-6-sulfonic acid (TNS). It therefore appears that low ionic strength, α-β association and neutral solute (or lowered dielectric constant) all induce a similar, but modest conformational change in the domain structure. The extent of TNS binding is not increased by lowering the ionic strength, suggesting that the expansion and/or stiffening of the molecule in low electrolyte solutions does not involve exposure of significant numbers of hydrophobic sites. © 1994 Wiley-Liss, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970290107
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 177
    Electronic Resource
    Electronic Resource
    Masthead (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994) 
    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.970290201
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 178
    Electronic Resource
    Electronic Resource
    Nanometer scale vibration in mutant axonemes of Chlamydomonas (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 177-185 
    Details
    ISSN: 0886-1544
    Keywords: flagella ; Chalamydomonas ; mutant ; high-frequency vibration ; nanometer scale measurement ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Flagellar axonemes of sea urchin sperm display high frequency (200-400 Hz) vibration with nanometer scale amplitudes in the presence of ATP [Kamimura and Kamiya, 1992: J. Cell Biol. 116:1443-1454]. To investigate how various axonemal components affect the vibration, we examined vibration in wild-type and mutant axonemes of Chlamydomonas. At 1 mM ATP, wild-type axonemes underwent vibration at 100-650 Hz with amplitudes of 4-40 nm. This vibration was similar to, but less regular than, that in sea urchin sperm. Axonemes of the mutants ida1 and ida4 lacking part of the inner arm dynein underwent vibrations indistinguishable from that of wild-type. The mutant oda1 lacking the entire outer arm underwent vibration at about half the wild-type frequency. Unexpectedly, the paralyzed mutants pf18 lacking the central pair and pf14 lacking the radial spokes displayed vibration with significantly higher frequencies and smaller amplitudes than those in the wild-type vibration. These results indicate that the high-frequency vibration is common to many kinds of mutant axonemes that lack various axonemal substructures, but that its manner is sensitive to the presence of outer arm dynein and the central pair/radial spoke system. Simultaneous measurements of amplitude and frequency in wild-type and mutant axonemes suggest that the velocity of microtubule sliding in vibrating axonemes is lower than the velocity of sliding under load-free conditions. The velocity is particularly low in pf18. A possible mechanism is proposed to explain the lower sliding velocity and vibration amplitude in the pf18 axoneme, based on an assumption that central pair/radial spoke system may work to regulate the switching of two antagonizing forces within the axoneme. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970290209
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 179
    Electronic Resource
    Electronic Resource
    Microtubules restrict plastid sedimentation in protonemata of the moss Ceratodon (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 366-374 
    Details
    ISSN: 0886-1544
    Keywords: cytoskeleton ; microfilaments ; cytochalasin ; gravity ; amiprophos-methyl ; tip-growth ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Apical cells of protonemata of the moss Ceratodon purpureus are unusual among plant cells with sedimentation in that only some amyloplasts sediment and these do not fall completely to the bottom of vertical cells. To determine whether the cytoskeleton restricts plastid sedimentation, the effects of amiprophos-methyl (APM) and cytochalasin D (CD) on plastid position were quantified. APM treatments of 30-60 min increased the plastid sedimentation that is normally seen along the length of untreated or control cells. Longer APM treatments often resulted in more dramatic plastid sedimentation, and in some cases almost all plastids sedimented to the lowermost point in the cell. In contrast, the microfilament inhibitor CD did not affect longitudinal plastid sedimentation compared to untreated cells, although it did disturb or eliminate plastid zonation in the tip. These data suggest that microtubules restrict the sedimentation of plastids along the length of the cell and that microtubules are load-bearing for all the plastids in the apical cell. This demonstrates the importance of the cytoskeleton in maintaining organelle position and cell organization against the force of gravity. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970290409
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 180
    Electronic Resource
    Electronic Resource
    Regulation of motility and cytoskeletal organization of rat bladder carcinoma cells by cyclic AMP (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 375-382 
    Details
    ISSN: 0886-1544
    Keywords: collagen ; actin ; α-actinin ; cAMP-dependent protein kinase ; NBT-II cells ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cyclic AMP (cAMP) has been implicated in the regulation of movement of certain cultured cell types. We have studied the effects of cAMP on epithelial cell motility using serum-free NBT-II cells, derived from a rat bladder carcinoma. The random movement of these cells on type I collagen was reduced upon elevation of intracellular cAMP by several means and this effect was reversible. Alterations in the organization of the cytoskeletal proteins F-actin and α-actinin occurred concurrently with the reduction in motility, and the arrangement of these proteins resembled that seen in non-motile cells on glass. In addition, pretreatment of cells with KT5720, a cAMP-dependent protein kinase (PKA)-specific inhibitor, prevented the dibutyryl cAMP-induced reduction in cell movement as well as the associated cytoskeletal changes. These results suggest that elevation of PKA is responsible for the observed effects on cell motility and cytoskeletal reorganization and demonstrate a role for PKA in the regulation of cell motility in this system. © 1994 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970290410
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 181
    Electronic Resource
    Electronic Resource
    Substructure of cytoplasmic dense bodies and changes in distribution of desmin and α-actinin in developing smooth muscle cells (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 204-214 
    Details
    ISSN: 0886-1544
    Keywords: intermediate filaments ; cytoskeleton ; filament attachment sites ; immunogold labeling ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The substructure of assembling cytoplasmic dense bodies (CDBs) and changes in the distribution of desmin and α-actinin during development of smooth muscle were studied in gizzard samples from 10- and 16-day embryos and from 1- and 7-day post-hatch chickens. CDBs in these cells lack the density of CDBs in mature or adult smooth muscle cells and, thus, allow observations of the changes inside CDBs. The random filament orientation seen in younger embryonic cells is first modified to include relatively small patches of IFs that are somewhat straighter and are approaching a side-by-side arrangement. As development proceeds, the IFs in these arrays become straighter, are parallel over longer lengths of the IFs and later acquire the density characteristic of mature CDBs. Anti-desmin labeling in embryonic 10- and 16-day cells showed that desmin intermediate filaments (IFs) were located in the myofilament compartment but were concentrated in or near assembling CDBs. Anti-desmin labeling shifted to the perimeter of CDBs after hatching. Cross sections, longitudinal sections, and stereo pairs all show that IF profiles are present inside unlabeled assembling CDBs. Anti-α-actinin labeling was directly on CDBs and was often associated with the cross-connecting filaments (CCFs) (average diameter of 2-3nm) inside CDBs. We propose, based on these data, that desmin IFs, α-actinin-containing CCFs, and actin filaments are the principal components of the substructure of assembling CDBs. We also present a proposed model for CDB assembly. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970290303
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 182
    Electronic Resource
    Electronic Resource
    Antibodies that can discriminate between dynein heavy chains and their HUV1 photoproducts (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 271-279 
    Details
    ISSN: 0886-1544
    Keywords: peptide antibodies ; protein processing ; axonemes ; microtubule associated proteins ; UV photocleavage ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Dyneins are multi-subunit enzymes that transduce chemical energy into the mechanical energy that makes cilia and flagella beat and moves organelles towards the minus end of microtubules. The ATPase activity is borne by heavy chains, and recent molecular analysis indicates that dynein heavy chain genes form an ancient multigene family: the similarity between the same isoform of two distantly related species is greater than that between different isoforms of the same species. We have exploited sequence identities between a Paramecium axonemal dynein heavy chain gene cloned in our laboratory and sequences of dynein heavy chains from other species to prepare antibodies against active-site peptides capable of recognizing dynein heavy chains regardless of species or isoform. One of the antibodies is perfectly specific for the larger product of V1 photolysis (HUV1) and thus incorporates a unique property of the hydrolytic ATP binding site of all known dynein heavy chains, the capacity for photocleavage in the presence of micromolar vanadate. Our characterization of these reagents suggests that they will be useful for biochemical and in situ studies of known dyneins as well as identification of potential new members of the family. © 1994 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970290310
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 183
    Electronic Resource
    Electronic Resource
    Extrusion of rotating microtubules on the dynein-track from a microtubule-dynein γ-complex (1995)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 30 (1995), S. 17-25 
    Details
    ISSN: 0886-1544
    Keywords: rotation ; twisting ; microtubule-dynein complex ; 22S dynein ; dynein-track ; ATP ; sliding ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Applying a new in vitro motility assay system for microtubules and 22S dynein, we recently reported on an ATP-induced extrusion of microtubules from microtubule-dynein α- and β-complexes [Mimori and Miki-Noumura, 1994:Cell Motil. Cytoskeleton 27:180-191]. In the present study, we prepared a γ-complex by copolymerizing porcine brain tubulin and Tetrahymena ciliary 22S dynein, and examined the ATP-induced microtubule movement from the γ-complex. The extrusion process appeared quite similar to that of the β-complex. The sliding velocity was 18.39 ± 2.20 m̈m/sec, which was a value comparable to that of trypsin-digested flagellar axonemes [Yano and Miki-Noumura, 1980:J. Cell Sci. 44:169-186]. Higher velocity may be due to a densely arranged dynein-track with the same polarity, which was detached from the γ-complex and absorbed in rows on a glass surface of the slide. Sometimes a free-floating microtubule in the perfusion chamber was observed riding and sliding on the dynein-track remaining on the slide after extrusion.Unexpectedly, we found that when the front part of the microtubule was fixed to a glass surface, a continuous sliding microtubule at the rear part on the dyneintrack often transformed into a left-handed helix, and subsequently a twisted helix with several turns. The helix formation may be due to some rigidity in the microtubule and a right-handed torque component in the sliding force of 22S dynein. The addition of ATP may release some distortion accumulated in the complex structure during copolymerization of tubulin and 22S dynein, inducing reverse rotation of the microtubule. © 1995 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970300104
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 184
    Electronic Resource
    Electronic Resource
    Masthead (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994) 
    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.970290401
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 185
    Electronic Resource
    Electronic Resource
    Interactions among endoplasmic reticulum, microtubules, and retrograde movements of the cell surface (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 291-300 
    Details
    ISSN: 0886-1544
    Keywords: endoplasmic reticulum ; DiOC6(3) ; microtubules ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Relationships among the endoplasmic reticulum (ER), microtubules, and bead movements on the cell surface were investigated in the thin peripheral region of A6 cells, a frog kidney cell line. ER tubules were often aligned with microtubules, as shown by double-labeling with DiOC6(3) and anti-tubulin in fixed cells. In living cells stained with DiOC6(3) and observed in time lapse, there were frequent extensions, but few retractions, of ER tubules. In addition, there was a steady retrograde (towards the cell center) movement of all of the ER at ∼0.3 μm/min. Since microtubules are often aligned with the ER, microtubules must also be moving retrogradely. By simultaneous imaging, it was found that the ER moves retrogradely at the same rate as aminated latex beads on the cell surface. This indicates that the mechanisms for ER and bead movement are closely related. Cytochalasin B stopped bead and ER movement in most of the cells, providing evidence that actin is involved in both retrograde movements. The ER retracted towards the cell center in nocodazole while both ER and microtubules retracted in taxol. Time lapse observations showed that for both drugs, the retraction of the ER is the result of retrograde movement in the absence of new ER extensions. Presumably, ER extensions do not occur in nocodazole because of the absence of microtubules, and do not occur in taxol because taxol-stabilized microtubules move retrogradely and there is no polymerization of new microtubule tracks for ER elongation. © 1994 Wiley-Liss, Inc.This Article is a US Government work and, as such, is in the public domain in the United States of America.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970290402
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 186
    Electronic Resource
    Electronic Resource
    Characteristics of pronuclear migration in Beroe ovata (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 301-311 
    Details
    ISSN: 0886-1544
    Keywords: ctenophore ; egg ; nucleus ; microtubule ; endoplasmic reticulum (ER) ; sperm aster ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In the large eggs (∼1 mm) of the ctenophore Beroe ovata, female pronuclei migrate long distances to join stationary male pronuclei in the peripheral cytoplasm that surrounds the yolky interior. We have investigated the mechanism of nuclear migration using time lapse video recording, automated image analysis, visualization of microtubules by immunofluorescence and rhodamine-tubulin injection, and electron microscopy. Female pronuclei migrated at average speeds of 0.2 μm/sec, and were found to show periodic oscillations in velocity. Alternating phases of acceleration and deceleration occurred with an average periodicity of 235 seconds covering distances of 47 μm (about 3 times the nuclear diameter). Migration velocities and velocity oscillations were similar in fertilized and unfertilized eggs; however, changes in migration direction were much more frequent in unfertilized eggs. Characteristic deformations of the pronuclear membrane and occasional rotation of the nuclear contents were observed during migration. Inhibitor studies indicated that microtubules are required for nuclear migration. In fertilized eggs the top of the nucleus was found to move through the dense layer of aligned sperm aster microtubules. The frequent changes in direction of pronuclear migration in unfertilized eggs reflect the random organization of the microtubule layer in the absence of sperm derived centrosomes. Densely packed endoplasmic reticulum was found intermeshed with sperm aster microtubules and connected extensively with the nuclear membrane during migration. Most nuclear pores were grouped in an infolding of the nuclear membrane. We suggest that in fertilized eggs the female pronucleus is transported to the minus ends of sperm aster microtubules using motor molecules attached either to the outer nuclear membrane and/or to the network of connecting ER. © 1994 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970290403
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 187
    Electronic Resource
    Electronic Resource
    Myosin I localizes to the midbody region during mammalian cytokinesis (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 29 (1994), S. 312-320 
    Details
    ISSN: 0886-1544
    Keywords: contractile ring ; cleavage furrow ; mitosis ; unconventional myosin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: During cytokinesis, daughter cells are cleaved in two by the constriction of an actin-rich contractile ring which encircles the equator of the dividing cell. Filamentous myosin II is present in the contractile ring and necessary for constriction of the furrow, as shown in several cell types [Satterwhite and Pollard, 1992: Curr. Opin. Cell Biol. 4:43-52]. However, no functional role nor distinctive localization has been previously identified for non-filamentous “unconventional” myosins, such as myosin I, during cytokinesis. Using antibodies to adrenal medullary myosin I, we report that myosin I is localized in 3T3 fibroblasts to the mid-equatorial plane during late-cytokinesis, as well as to the polar edges as previously described in ameboid cells [Fukui et al., 1989: Nature 341:328-331]. Confocal microscopy revealed that myosin I is concentrated at the midbody region in a nearly continuous transverse disk, extending from the cortical region of the furrow through the midbody itself. These findings suggest that, in addition to the accepted role of filamentous myosin II in constriction of the contractile ring, non-filamentous myosin I might contribute to motile events occurring late in cytokinesis. © 1994 Wiley-Liss, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970290404
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 188
    Electronic Resource
    Electronic Resource
    cAMP/ATP relationship in the activation of trout sperm motility: Their interaction in membrane-deprived models and in live spermatozoa (1995)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 31 (1995), S. 159-176 
    Details
    ISSN: 0886-1544
    Keywords: trout ; spermatozoa ; ATP ; cAMP ; axoneme ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Live trout spermatozoa initiate flagellar motility for only a short period (30 sec at 18°C) during which their mean beat frequency decreases steadily from 60 to 20 Hz. Motility then stops abruptly. Investigations of the activation of movement in demembranated sperm points to cyclic-AMP being necessary for reactivation (half effect at 0.5μm) in some conditions. cAMP acts mainly by increasing the percentage of motile cells and not the beat frequency (BF) of the flagellar axoneme. Dibutyryl cAMP does not initiate movement or prolong motility of live sperm.The initiation of movement of demembranted trout sperm was investigated in various incubation conditions relative to previous phases of in vivo movement and to ATP concentration. In the absence of cAMP and in the presence of ATP lower than 25 μM, all sperm celi models were active with BF up to 15-20 Hz whatever their previous physiological condition. In contrast, at ATP concentrations above 100 μM, the fraction of active spermatozoa decreased proportionally but the BF of the active ones increased so that, at 1 mM ATP up to 20 μM restored activity to 100% sperm models with a similar BF of 65 Hz.At ATP concentrations higher than 25 μM, cAMP was necessary in a concentration dependent manner in the reactivation, but not in the demembranation meduim. This dependence was found to be unrelated to a previous in vivo phase of movement. The antagonistic effects of ATP vs. cAMP were tested at various concentrations of both nucleotides: the apparent affinity for cAMP, measured as the concentration restoring movement of 50% cell models, was decreased from 15 nM at 0.1 mM ATP to 0.5 μM at 1 mM ATP; conversely, the affinity for ATP, measured as the concentration giving rise to the half maximal beat frequency, was not significautly affected when the concentration of cAMP was raised to 0.5 mM. Preincubation with phosphodiesterase (PDE) resulted in motility of 100% of sperm models even at low ATP concentration. This tends to show that cAMP must be constantly present to sustain motility.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970310208
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 189
    Electronic Resource
    Electronic Resource
    Role of the cytoskeleton in the reaction of fibroblasts to multiple grooved substrata (1995)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 31 (1995), S. 147-158 
    Details
    ISSN: 0886-1544
    Keywords: actin ; contact guidance ; microfilaments ; microtubules ; orientation ; cytochalasin ; colcemid ; taxol ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The role of the cytoskeleton and cell attachments in the alignment of baby hamster kidney fibroblasts to ridge and groove substratum topography was investigated using confocal scanning microscopy. This was carried out with normal cells and cells treated with the cytoskeleton modifiers cytochalasin D, colcemid, and taxol. Actin was localised with fluorescent phalloidin. Tubulin, Vinculin, and intracellular adhesion molecule-1 were visualised by indirect immunofluoresence. The spreading, elongation, and orientation of the cells after 24 h of culture in these conditions were measured on grooves of 5, 10, and 25 μm width and 0.5, 1, 2, and 5 μm depth. We have also observed events over the first 30 min of cell attachment. Five minutes after cell attachment, F-actin condensations were seen close to the intersection of groove wall and ridge top, that is, at a topographic discontinuity. The condensations were often at right angles to the groove edge and showed a periodicity of 0.6 μm. Vinculin arrangement at the early stages of cell spreading was similar to that of actin. Organisation of the microtubule system followed later, becoming obvious at about 30 min after cell plating. The Curtis and Clark theory (that cell react to topography primarily at lines of discontinuity in the substratum by actin nucleation) is supported by these results. The use of cytoskeletal poisons did not entirely abolish cell reaction to grooves. Colocemid increased cell spreading and reduced cell orientation and elongation. Cytochalasin D reduced cell spreading, orientation, and elongation. Taxol reduced cell elongation but did not affect cell spreading and orientation. We conclude that the aggregation of actin along groove/ridge boundaries is a primary driving event in determining fibroblast orientation on microgrooved substrata.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970310207
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 190
    Electronic Resource
    Electronic Resource
    Masthead (1995)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 30 (1995) 
    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.970300201
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 191
    Electronic Resource
    Electronic Resource
    Desmosome assembly and disassembly are regulated by reversible protein phosphorylation in cultured epithelial cells (1995)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 30 (1995), S. 108-121 
    Details
    ISSN: 0886-1544
    Keywords: intercellular junctions ; desmosome ; assembly ; kinase ; phosphatase ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Desmosomes are one component of the intercellular junctional complex in epithelia. In cultures of epithelial cells, desmosome assembly can be regulated by modulating the calcium concentrations of the growth media. At present, very little is known about the intracellular signal transduction mechanisms that regulate desmosome assembly and disassembly in response to changing extracellular calcium concentrations. We have used inhibitors of protein kinases and phosphatases in a combined biochemical and morphological approach to analyze the role of protein phosphorylation in the assembly and disassembly of desmosomes in Madin-Darby canine kidney epithelial cells. Our results suggest that desmosomal proteins (desmoplakins I/II and desmoglein 1) are primarily phosphorylared on serine residues. Electron microscopic analyses of desmosome assembly upon induction of cell-cell contact, in the presence of protein kinase inhibitor, H-7, revealed an apparently normal assembly of desmosomes. However, complete disassembly of desmosomes was inhibited by H-7 upon removal of extracellular calcium. Under these conditions, although desmosomes split, desmosomal plaques and their associated cytokeratin filaments can not be internalized. In contrast, treatment of the cultures with okadaic acid (OA), an inhibitor of protein phosphatases, inhibited desmosome assembly but had no effect on disassembly. In addition, the inhibitory effect of okadaic acid on desmosome assembly was specific to this junction since we observed apparently normal tight junction and adherens junction in okadaic acid-treated cultures. These results suggest that via reversible protein phosphorylation involving both protein kinase and protein phosphatases. © 1995 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970300203
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 192
    Electronic Resource
    Electronic Resource
    Exogenous gelsolin binds to sarcomeric thin filaments without severing (1995)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 31 (1995), S. 196-206 
    Details
    ISSN: 0886-1544
    Keywords: gelsolin ; actin ; myofibrils ; immunofluorescence ; nebulin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have investigated the binding of gelsolin to thin myofilaments in situ and their stability against severing. Differentiated myotubes from chicken skeletal muscle containing cross-striated myofibrils were permeabilized with Triton X-100 and incubated with gelsolin. Immunoflurorescence microcopy localized both endogenous and exogenous gelsolin in the I-Z-I-regions of the sarcomers. The staining pattern suggested a binding of the exogenous gelsolin along the entire length of the thin filaments. This binding was Ca2+ dependent, but gelsolin was not removed after subsequent addition of EGTA. The fluorescence staining for actin remained unchanged after gelsolin incubation, indicating that thin filaments in cross-striated myofibrils were resistant to the severing action of gelsolin, in contrast to the microfilaments in stress fibers. After extraction of the permeabilized cells with high ionic strength to remove tropomyosin and myosin, gelsolin stell bound along the entire thin filament and the actin pattern also remained unchanged. After Triton X-100 permeabilization and high ionic strength extraction, the giant protein nebulin was found to be still present as a myofibrillar component. Gelsolin treatment after high salt extraction affected neither actin nor nebulin in the thin filaments. We therefore conclude that nebulin confers the gelsolin resistance to the sarcomeric actin filaments.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970310303
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 193
    Electronic Resource
    Electronic Resource
    Novel mode of hyper-oscillation in the paralyzed axoneme of a chlamydomonas mutant lacking the central-pair microtubules (1995)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 31 (1995), S. 207-214 
    Details
    ISSN: 0886-1544
    Keywords: flagella ; Chlamydomonas ; mutant ; high-frequency vibration ; nanometer-scale measurement ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The flageliar axoneme of the mutant pf18 lacking the central pair does not beat, but undergoes a nanometer-scale, high-frequency oscillation (hyper-oscillation) in the presence of ATP [Yagi et al., 1994: Cell Motil, Cytoskeleton 29:177-185]. The present study demonstrates that the amplitude of the hyper-oscillation increases significantly in the simultaneous presence of ATP and ADP. In addition, the hyper-oscillation under these conditions sometimes takes on an exceptionally simple asymmetric pattern, in which the maximal shearing velocity exceeds 50 μm/sec, much higher than the maximal velocity of ordinary dynein-microtubule sliding. The asymmetric oscillation thus appears to be at least partly driven by an internal elastic force. Its amplitude suggests that the axoneme has an elastic component that can be stretched by as long as 0.1 μm. Analyses of the asymmetric pattern further suggests that the axonemal dyneins have a tendency to attach to and detach from the doublets cooperatively and that the mechanochemical cycle of dynein has an inherent refractory period of about 2 msec, during which dynein cannot interact with microtubules.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970310304
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 194
    Electronic Resource
    Electronic Resource
    Traction forces in locomoting cells (1995)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 31 (1995), S. 225-240 
    Details
    ISSN: 0886-1544
    Keywords: cell-substratum adhesion ; lamellar contractility ; locomotion ; silicone rubber ; traction forces ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A means of determining quantitative maps of the tractions exerted by locomoting cells on a substratum has been developed. This method is similar to the Harris silicone substratum assay [Harris et al., 1980: Science 208:177-179], but uses an improved non-wrinkling film that deforms more predictably in response to traction forces. The method also utilizes a mathematical analysis of rubber deformation to produce the final map of the distribution of tractions. The resulting maps consistently showed that fish keratocytes exert a steady-state “pinching” on the substratum, perpendicular to the cell's direction of locomotion. No significant rearward tractions were detected at or near the front edge of the cell. Likewise, no significant forward tractions associated with peeling of adhesions were found at the back of the cell. A second assay uses deflection of a lightly attached glass microneedle to measure the total force exerted by locomoting cells. Forces of approximately 4.5 × 10-3 dyn were required to “stall” locomoting keratocytes. The implications of these findings for cell movement are discussed.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970310306
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 195
    Electronic Resource
    Electronic Resource
    Dynamics of triton-insoluble and triton-soluble F-actin pools in calcium-activated human polymorphonuclear leukocytes: Evidence for regulation by gelsolin (1995)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 30 (1995), S. 136-145 
    Details
    ISSN: 0886-1544
    Keywords: microfilamentous cytoskeleton ; actin binding proteins ; actin polymerization ; annealing ; non-muscle cells ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Gelsolin, a Ca++ activated, 90 kd actin binding protein, can regulate actin polymerization in polymorphonuclear leukocytes (PMNs) via severing of filaments to dissolve gels or by capping of filament ends to limit polymerization. In Triton-lysed PMNs, 30% of gelsolin is bound to the Triton-soluble F-actin (TSF) pool and none is bound to the Triton-insoluble F-actin (TIF) pool. Calcium-activated PMNs exhibit concurrent temporal and quantitative TIF growth and TSF and total F-actin loss. To determine if gelsolin plays a role in regulating TSF pool size, we monitored gelsolin-actin interactions and TIF, TSF and G-actin content at 5 second intervals in PMNs activated with the calcium ionophore, ionomycin. Actin pools were measured by NBDphallacidin binding and by gel scans and expressed relative to basal; gelsolin-actin interactions were measured as change in the amount of EGTA-resistant gelsolin:actin (G:A) complexes and by immunoblot quantification of gelsolin in actin pools. In basal PMNs, 33% of PMN gelsolin is bound in 1:1 EGTA-resistant G:A complexes and TSF and TIF retain 30% and 0% of PMN gelsolin, respectively. By 20 seconds after ionomycin addition, TSF decreases, TIF increases and a fraction of gelsolin repartitions from the TSF to the TIF pool. At maximum change (60 seconds), total F-actin (TIF + TSF) and TSF decrease and TIF increases by 25%; gelsolin is bound to both TSF and TIF (35% of total gelsolin in each pool), and 1:1 EGTA-resistant G:A complexes increase from 33% to 70%. No changes occur in cells activated by ionomycin in the absence of Ca++. The data show Ca++ activated TIF growth and TSF loss are temporally and quantitatively associated with an increase in the percent of gelsolin bound to actin and the translocation of gelsolin from TSF to TIF. This is unique, since no other PMN activator is known to repartition gelsolin into TIF actin. Further, the Ca++ activated initial increase in TIF concurrent with a fall in TSF without a change in total F-actin or G-actin content suggest that TIF grows initially only by TSF annealing/cross-linking to TIF. Gelsolin may regulate these events. © 1995 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970300205
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 196
    Electronic Resource
    Electronic Resource
    Kinesin does not support the motility of zinc-macrotubes (1995)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 30 (1995), S. 146-152 
    Details
    ISSN: 0886-1544
    Keywords: zinc-sheets ; macrotubes ; kinesin ; electron microscopy ; microtubules ; tubulin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Moving along a microtubule, kinesin follows a course parallel to the protofilaments; but it is not known whether kinesin binds exclusively on a single protofilament. The presence of zinc during tubulin polymerization induces sheets where neighboring protofilaments are antiparallel. If kinesin could support the motility of these zinc-sheets, then the binding site for a kinesin molecule would be limited to a single protofilament.Kamimura and Mandelkow [1992: J. Cell Biol. 118:865-75] reported that kinesin moves along zinc-sheets. We found that zinc-sheets grown under their conditions often had a microtubule-like structure along one edge. We confirmed the possibility that the motility observed by Kamimura and Mandelkow [1992: J. Cell Biol. 118:865-75] is attributed to the microtubule-like structure rather than the zinc-sheet.To resolve the question of whether kinesin can recognize an antiparallel protofilament lattice, we investigated the kinesin-mediated motility of zinc-macrotubes. At higher free zinc concentrations, zinc-sheets roll up as macrotubes, free of edges. In the presence of 10 m̈M taxol and 100 nM free Zn2+ at pH 6.8, the samples were shown by electron microscopy to contain only macrotubes. Under these buffer conditions, kinesin could bind strongly to axonemal doublets in the presence of AMP-PNP, and generate motility in the presence of ATP, but kinesin did not bind to nor move the macrotubes. This shows that kinesin cannot bind efficiently to nor move on the anti-parallel lattice; it is possible (though not necessary) that the groove between two parallel protofilaments is required for kinesin's motility. © 1995 Wiley-Liss, Inc.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970300206
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 197
    Electronic Resource
    Electronic Resource
    Masthead (1995)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 30 (1995) 
    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.970300301
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 198
    Electronic Resource
    Electronic Resource
    Comparative study of the colchicine binding site and the assembly of fish and mammalian microtubule proteins (1995)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 30 (1995), S. 153-163 
    Details
    ISSN: 0886-1544
    Keywords: colchicine binding site ; MTC ; cod microtubules ; bovine microtubules ; MAPs ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Isolated microtubules from cod (Gadus morhua) are apparently more stable to colchicine than bovine microtubules. In order to further characterize this difference, the effect of the colchicine analogue 2-methoxy-5-(2,3,4-trimethoxyphenyl)-2,4,6-cyclo heptatrien-1-one (MTC) was studied on assembly, as measured by turbidity and sedimentation analysis, and on polymer morphology. MTC has the advantage to bind fast and reversible to the colchicine binding site of tubulin even at low temperatures. It was found to bind to one site in cod brain tubulin, with affinity (6.5 ± 1.5) × 105M 1at both low or high temperature, similarly to bovine brain tubulin. However, the effect of the binding differed. At substoichiometric concentrations of MTC bovine brain microtubule assembly was almost completely inhibited, while less effect was seen on the mass of polymerized cod microtubule proteins. A preformed bovine tubulin-colchicine complex inhibited the assembly of both cod and bovine microtubules at substoichiometric concentrations, but the effect on the assembly of cod microtubules was less. At higher concentrations (5 × 10-5 to 1 × 10-3M), MTC induced a large amount of cold-stable spirals of cod proteins, whereas abnormal polymers without any defined structure were formed from bovine proteins. Spirals of cod microtubule proteins were only formed in the presence of microtubule associated proteins (MAPs), indicating that the morphological effect of MTC can be modulated by MAPs. The effects of colchicine and MTC differed. At 10-5M colchicine no spirals were formed, while at 10-4M and 10-3M, a mixture of spirals and aggregates was found. The morphology of the spirals differed both from vinblastine spirals and from the spirals previously found when cod microtubule proteins polymerize in the presence of high Ca2concentrations. The present data show that even if the colchicine binding site is conserved between many different species, the bindings have different effects which seem to depend on intrinsic properties of the different tubulins. © 1995 Wiley-Liss, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970300207
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 199
    Electronic Resource
    Electronic Resource
    Cytoskeleton of the Drosophila egg chamber: New observations on microfilament distribution during oocyte growth (1995)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 31 (1995), S. 298-306 
    Details
    ISSN: 0886-1544
    Keywords: Drosophila ; nurse cells ; oocyte ; microfilaments ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The distribution of microfilaments in Drosophila egg chambers stained with rhodamine (Rh)-conjugated phallcidin was studied by laser scanning confocal microscopy and transmission electron microscopy. These techniques revealed new details in the pattern of microfilament localization. We observed in stage 1-3 egg chambers accumulation of filamentous actin in the oocyte cytoplasm between the ring canals connecting the oocyte with adjacent nurse cells. Starting from stages 6-7 short microfilament bundles arranged in basket-like structures were associated with the side of the ring canals facing the nurse cell cytoplasm. We also observed a dramatic decrease in the actin network associated with the cortex of the oocyte in stage 10. During stage 10B the nurse cell cytoplasm was crossed by radial actin bundles that showed a sarcomeric-like cross striation after Rh-phalloidin staining. The ring canals also did not uniformly stain but showed a punctate labeling. The implications of the actin cytoskeleton during oocyte growth are discussed. © 1995 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970310406
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 200
    Electronic Resource
    Electronic Resource
    Porcine brain neurofilament-H tail domain kinase: Its identification as cdk5/p26 complex and comparison with cdc2/cyclin B kinase (1995)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 31 (1995), S. 283-297 
    Details
    ISSN: 0886-1544
    Keywords: neurofilament ; phosphorylation ; cdk5 ; cdc2 ; cyclin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Using dephosphorylated neurofilament (NF) proteins as substrates, the kinase with a higher activity for in the dephosphorylated NF-H than the phosphorylated form of NF-H was searched for in the porcine brain extract. Most NF-H kinase activity in the brain extract pelleted with microtubules. The NF-H kinase purified from a high salt extract of the microtubule pellets was composed of cdk5 and a 26 kDa protein, a fragment of the 35 kDa regulatory subunit of cdk5. In contrast to the association of the active kinase with microtubules, each of uncomplexed cdk5 and the 35 kDa regulatory subunit was differently distributed in the supernatant fraction and the pellet, respectively, by ultracentrifugation of the brain extract. Dephosphorylated forms of NF-H and NF-M became reactive to antibodies recoginizing in vivo phosphorylation sites (SM131, 34, and 36, JJ31 and 51) by phosphorylation with cdk5/p26. cdk5/p26 showed similar enzymatic properties to p34cdc2/cyclin B kinase; the substrate specificity and inhibition by a p34cdc2 kinase specific inhibitor, butyrolactone I. However, p34cdc2/cyclin B kinase was distinguished from cdk5/p26 by its binding to p13suc1 protein and by its reactivity to anti-p34cdc2 antibodies. In spite of similar enzymatic properties of cdk5/p26 and p34cdc2/cyclin B kinase, cdk5/26 did not display M-phase promoting activity when assayed with a cell-free system of Xenopus egg extract. © 1995 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970310405
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...