ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

Your email was sent successfully. Check your inbox.

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

Proceed reservation?

Export
Filter
  • Life and Medical Sciences  (3,416)
  • Cell & Developmental Biology  (2,672)
  • 1980-1984  (3,416)
Collection
Publisher
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984) 
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 371-385 
    ISSN: 0886-1544
    Keywords: microtubules ; dynein ; tubulin ; cilia and flagella ; microtubule associated proteins ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Dynein, obtained from axonemes of Chlamydomonas, binds by both its A and B ends to microtubules assembled from twice cycled (2 ×) and purified (6S) brain tubulin as well as to microtubules in native spindles, thereby inducing microtubule crossbridging. The two ends of the dynein arm exhibit distinct binding characteristics for the different microtubule preparations. Greater than 99% of the dynein arms are bound exclusively by their B ends to microtubules assembled from 6S tubulin in the presence of dynein and decorated to saturation. In contrast, greater than 80% of the dynein arms are bound by both their A and B ends to and, therefore, crossbridge 6S microtubules that are only partially dynein decorated. Binding of the A end of the dynein arm to saturated 6S microtubules can be enhanced by destabilizing the binding of the B end upon addition of ATP and vanadate. These observations suggest that Chlamydomonas dynein arms can bind by their A ends to microtubules assembled from 6S tubulin only when the B ends of the arms either are not bound or are bound but do not occupy all available dynein binding sites. Dynein exhibits a slight preference for binding by its A end to microtubules assembled from 2 × tubulin and containing microtubule associated proteins (MAPs). Approximately 90% of the dynein arms crossbridge adjacent 2 × microtubles that are only partially decorated. But as saturation of these microtubules with dynein is approached, the majority of the arms are bound solely by their A ends, while a smaller percentage are bound by their B ends or by both their A and B ends. These studies indicate that the type of microtubule as well as the degree of saturation of the microtubule with dynein can determine whether microtubule crossbridging occurs.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 431-441 
    ISSN: 0886-1544
    Keywords: dynein ; chromatophores ; permeabilization ; melanosomes ; motility ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Teleost chromatophores are filled with individual pigment granules that rapidly aggregate to the cell center or become dispersed throughout the cytoplasm in response to environmental stimuli. Microtubules appear to be required for pigment aggregation (movement toward the cell center), and recent findings have suggested that a dynein-like ATPase may participate in force production. Based on previous studies, however, it has been argued that pigment aggregation does not require energy directly, a view that supports the involvement of an elastic component in granule movement. To examine this point further, we have reinvestigated the energy requirements for pigment aggregation using both intact cells and detergent-permeabilized cell models of Fundulus melanophores. Poisons of oxidative phosphorylation, namely, 2,4 dinitrophenol and NaCN, reversibly inhibit melanosome aggregation in response to adrenaline. Inhibition of movement results directly from depletion of intracellular ATP, since pigment translocation can be reactivated in permeabilized cells by the addition of exogenous ATP to the lysis buffer. Non-hydrolyzable analogues, including β,γ-imidoadenosine-5′-triphosphate (AMPPNP), β,γ-methylene adenosine-5′-triphosphate (AMPPCP), and ATPγS, will not substitute for ATP in reactivation of movement. Similarly, other nucleotides such as ADP, AMP, GTP, CTP, and ITP, have limited ability to support melanosome aggregation in metabolically poisoned cells subjected to detergent lysis. ATP itself has no effect on intact cells. These results indicate that melanosome aggregation is ATP-dependent and energy-driven, and are consistent with a role for a force-transducing ATPase in particle movement.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984) 
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 41-55 
    ISSN: 0886-1544
    Keywords: Leptodiscinae ; Dinoflagellates ; contractility ; non-actin filaments ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The Leptodiscinae, a group of marine Dinoflagellates, are good material for the study of contraction though they cannot be collected in abundance. Their cell bodies are flattened anteroposteriorly (Leptodiscus, Leptophyllus, and Leptospathium) and are able to contract suddenly when the surrounding water is disturbed.Electron microscopical observations have shown that the structures responsible for the contraction consist of a layer of parallel filaments located beneath the cell membrane of some specialized parts of the body. These filaments seem to be nonactin (NAF) because of their diameter (2.5-3 nm) and because they are not decorated by heavy meromyosin (HMM). They appear helically coiled and doubly twisted, and form tubular structures when contracted.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 25-27 
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 183-196 
    ISSN: 0886-1544
    Keywords: tubulin ; assembly ; mitotic apparatus ; bimane ; fluorescence microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fluorescent derivatives of cellular proteins that retain their native characteristics have become useful probes to investigate the dynamics of specific cytoskeletal proteins. In the experiments reported here, a previously characterized fluorescent derivative of tubulin, bimane-tubulin [Wadsworth and Sloboda, 1982a], was used to investigate microtubule assembly in vitro. The results demonstrate that bimanetubulin was competent to assemble onto a variety of organizing centers in vitro, including microtubule organizing centers (MTOCs) present in homogenates of sea urchin eggs, isolated mitotic apparatuses (MAs), and lysed mitotic cells. When homogenates of fertilized sea urchin eggs containing MTOCs were incubated with bimane-tubulin at 37°C, discrete areas of linear fluorescence were observed. Only diffuse fluorescence was observed when calcium or colchicine was added to the homogenate or if the temperature was maintained at 0°C. Negative-stain electron microscopy of the fluorescent arrays revealed morphologically normal microtubules radiating from electron dense regions. When mitotic spindles, isolated in glycerol containing buffers and therefore cold stable, were incubated with bimane-tubulin, linear fluorescence was observed emanating from the spindle poles but not from the region occupied by the kinetochores. MAs incubated with bimane-labeled bovine serum albumin or bimane-labeled microtubule-associated proteins showed only diffuse fluorescence. However, when mitotic cells which were hypotonically lysed in the absence of detergents or microtubule stabilizing solvents, were perfused with bimane-tubulin intense fluorescence was observed in the asters and throughout the spindle. Two experiments suggested that the fluorescence observed in the results outlined above was due to the assembly of normal microtubules from the fluorescent subunits. First, the observed fluorescence was sensitive to cold temperataure, which is known to disassemble microtubules. Second, when the isolated, fluorescent MAs were examined by thin section electron microscopy, microtubules of normal diameter were seen. No aggregated material appeared associated with the walls of the microtubules, which might have been expected if the fluorescent protein was nonspecifically adsorbed to the microtubules. The results of these experiments demonstrate that isolated, stabilized MAs support the growth of new microtubules from the spindle poles while labile spindles, present in lysed cells, incorporate fluorescent tubulin throughout the spindle and asters. The significance of these results for hypotheses concerning microtubule assembly and disassembly during mitosis is discussed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 7-23 
    ISSN: 0886-1544
    Keywords: axoplasm ; elastic modulus ; viscosity ; motility ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A magnetic sphere viscoelastometer has been developed to peform rheological experiments in living axoplasm of Loligo pealei. The technique includes the use of a calibrated magnetic sphere viscoelastometer on surgically implanted ferro-magnetic spheres in intact squid giant axons. The axoplasm was discerned to be “living” by the biological criterion of tubulovesicular organelle motility, which was observed before and after experimentation. From these in vivo experiments, new structural characteristics of the axoplasm have been identified. First, analysis of magnetic sphere trajectories has shown the axoplasm to be a complex viscoelastic fluid. Directional experimentation showed that this material is structurally anisotropic, with a greater elastic modulus in the direction parallel to the axon long axis. Second, both magnetic sphere and in vivo capillary experiments suggested that the axoplasm is tenaciously anchored to the axolemma. Third, it was found that axoplasm could be modelled as a linear viscoelastic material in the low shear rate range of 0.0001 to 0.004 s-1. The simplest mechanical model incorporating the discovered properties of the material in this range is Burger's model.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984) 
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 103-119 
    ISSN: 0886-1544
    Keywords: cilia ; metachrony ; serum immunoglobulins ; IgM ; Mytilus edulis ; cystic fibrosis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Human IgM and a bovine, IgM-enriched serum fraction isolated from normal adult serum at concentrations of 0.25-1 mg/ml protein induced a pronounced increase in the metachronal wavelength of the lateral (L) cilia of the sea mussel Mytilus edulis without altering their beat frequency. This change in activity was indistinguishable from that induced by 50% adult human or bovine serum. At protein concentrations ranging from 1-9 mg/ml, human IgG or a bovine, IgG-enriched serum fraction had no or little effect on the activity of the L cilia. Similarly, neither monomeric (8S) human IgM (0.25 mg/ml) nor monospecific pentameric IgM (1 mg/ml) isolated from Waldenström's macroglobulinemia patients altered the metachrony of the L cilia. Indirect immunofluorescence demonstrated that both bovine and human IgM became attached almost exclusively to the L cilia, while very little bovine or human IgG was found to associate with these cilia.The results of this study suggest that serum IgM specifically binds to the L cilia of Mytilus in an antigen-antibody manner and agglutinates adjacent cilia into blocks or bundles, thereby increasing the coupling between cilia. As a result, the wavelength of the metachronal coordination is increased. The origin of these ciliary antibodies and their significance to ciliary bioassays used to monitor serum for the detection of cystic fibrosis are discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 11
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 417-430 
    ISSN: 0886-1544
    Keywords: flagella ; image analysis ; microcomputer ; motility ; parameter estimation ; Simplex method ; spermatozoa ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Parameters to describe flagellar bending patterns can be obtained by a microcomputer procedure that uses a set of parameters to synthesize model bending patterns, compares the model bending patterns with digitized and filtered data from flagellar photographs, and uses the Simplex method to vary the parameters until a solution with minimum root mean square differences between the model and the data is found. Parameters for Chlamydomonas bending patterns have been obtained from comparison of shear angle curves for the model and the data. To avoid the determination of the orientation of the basal end of the flagellum, which is required for calculation of shear angles, parameters for sperm flagella have been obtained by comparison of curves of curvature as a function of length for the model and for the data. A constant curvature model, modified from that originally used for Chlamydomonas flagella, has been used for obtaining parameters from sperm flagella, but the methods can be applied using other models for synthesizing the model bending patterns.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 12
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 77-87 
    ISSN: 0886-1544
    Keywords: Chlamydomonas ; flagella ; cell surface ; adhesion ; glycoproteins ; iodination ; lactoperoxidase ; Iodogen ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The Chlamydomonas flagellar surface exhibits interesting adhesive properties that are associated with flagellar surface motility. This dynamic surface property can be exhibited as the binding and movement of small polystyrene microspheres or as the interaction of the flagellar surface with a solid substrate followed by whole cell locomotion, termed “gliding.” In order to identify flagellar surface proteins that mediate substrate interaction during flagellar surface motility, two immobilized iodination systems were employed that mimic the conditions for flagellar surface motility: small polystyrene microspheres derivatized with lactoperoxidase, and large glass beads derivatized with Iodogen. Use of these iodination conditions resulted in preferential iodination of a high-molecular-weight glycoprotein with apparent molecular weight of 300,000-350,000. These results suggest this glycoprotein as a major candidate for the surface-exposed adhesive component that directly interacts with the substrate and couples the substrate to a system of force transduction presumed to be located within the flagellum.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 13
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 129-135 
    ISSN: 0886-1544
    Keywords: amoeboid motion ; chemoattractants ; chemotaxis ; Dictyostelium ; filopodia ; folic acid ; pterins ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Living vegetative D. discoideum amoebae were studied to determine whether their filopodia respond to folic acid, a chemoattractant for these cells. Exponentially growing amoebae (ca. 10 μm diameter) exhibit 5-30 μm long filopodia; at stationary phase, aggregation competent amoebae have numerous multibranched filopodia up to 100 μm long. Folic acid was observed to stimulate production, elongation, and branching of filopodia with its effects progressively changing as the amoebae approach aggregation. Filopodial construction was also found to be dependent upon Mg2+ levels. The significance of these results is discussed with respect to progressive changes within the vegetative phase as well as to the mechanisms of amoeboid movement, pseudopodial activity, and chemotaxis.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 14
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 29-40 
    ISSN: 0886-1544
    Keywords: microfilaments ; microtubules ; contraction ; collagen gel ; fibroblasts ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In vitro models have been developed recently to study the ability of fibroblasts to generate tensile force within collagen gels. The present study was initiated to assess the role of the cytoskeleton in the cell shape changes and force generation in one such model system. Porcine periodontal ligament fibroblasts (PPLF) were cultured within three-dimensional collagen gels attached to glass coverslips. Fluorescence microscopy, using nitrobenzooxadizole (NBD)-phallacidin labeling for microfilaments and tubulin antibody staining for microtubules, was combined with phase and Nomarski optics to determine the intra- and extracellular architecture of the cells and collagen fibers. Samples were observed from 30 minutes to 24 hours after initiation of cell attachment. During attachment and spreading, NBD-phallacidin staining changed dramatically until large microfilament bundles became prominent. Collagen fiber alignment, compaction, and finally tearing from the coverslip occurred during this time. After release of tension, microfilament bundles were no longer evident. The change in microtubule distribution during these processes was less dramatic, appearing to follow the change in cell shape. These results indicate that microfilaments play an essential role in generating force to align and compact collagen, while microtubules may have a secondary role only.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 15
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 241-247 
    ISSN: 0886-1544
    Keywords: cytoskeleton ; centrosome ; tonofilaments ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We present observations on the relative location of the centriole and keratin filament cap in motile PtK1 cells. Subconfluent cells were double labeled with anticentriole and antikeratin sera. These preparations revealed that the centriole is separate from, but neighboring, the keratin filament cap. Serial ultrathin sections confirm this observation. These observations are consistent with the idea that the microtubule organizing center and intermediate filament distribution center are not identical or concentric in PtK1 cells.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 16
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 169-181 
    ISSN: 0886-1544
    Keywords: cytoskeleton ; motility ; cell spreading ; epithelial cells ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Reorganization of intermediate filaments during cell spreading is examined by immunofluorescence, electron microscopy, and time-lapse video microscopy. A juxtanuclear cap, believed to correspond to the intermediate filament distribution center, was observed to be spatially related to the organization of the intermediate filament network as cells spread. A keratin cap was observed, which appeared spontaneously in motile PtK1 cells. Cap formation may be a consequence of retraction of intermediate filaments from the cytoplasm as cells move. The position of this juxtanuclear cap is related to the direction of movement, located on the side of the nucleus near the advancing edge of the cell. As the cell spreads, the cap disappears as the keratin filament network returns to the cytoplasm. Evidence presented here is consistent with the hypothesis that the distribution center mediates keratin filament organization during cell shape change.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 17
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 227-229 
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 18
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 269-281 
    ISSN: 0886-1544
    Keywords: microtubules ; microfilaments ; filopodia ; cell spreading ; coelomocytes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Sea urchin coelomocytes were used as a model system to investigate the distribution and role of microtubules and microfilaments in cell spreading and filopodial formation. By using immunoblot characterized antisera to tubulin and actin coupled with immunofluorescence techniques, cellular protrusions were seen to contain actin filaments but no microtubules. Cells depleted of MT's by cold and colcemid treatments could attach, spread, and transform to the filopodial morphology normally.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 19
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 297-303 
    ISSN: 0886-1544
    Keywords: exocytosis ; chromaffin cells ; vesicle release ; light microscope ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cultured bovine adrenal medullary chromaffin cells were stimulated with the secretogogues Ba2+ or carbamyl choline plus Ca2+. With video-enhanced contrast, differential interference contrast microscopy, small vesicles were found to appear on the cell surface during stimulation. The structures were of lower refractive index than the cytoplasm, and their appearance required several tenths of a second. The vesicles are thought to correspond to omega figures seen with electron microscopy due to exocytosis. Many of the structures disappeared within a few seconds, but some appeared to coalesce into larger structures. The large structures may lead to the vacuoles that have been demonstrated to be present following stimulation. The nature of the cellular elements responsible for the vesicle which appeared on the surface was not found with either differential interference or interference reflection microscopy. The simplest explanation is that the refractive index of the elements is similar to that of the cell, and therefore the elements cannot be seen.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 20
    ISSN: 0886-1544
    Keywords: fibroblast ; permeabilized cell model ; Ca2+-dependent contraction ; calmodulin ; phosphorylation ; myosin light chain ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Human lung fibroblast MRC-5 cells treated with Triton X-100 (MRC-5 cell models) were able to contract in the presence of MgATP and Ca2+ of more than 1 μM. Immunofluorescence microscopy with antibodies to actin and myosin 20,000-dalton (20 Kd) light chain revealed that stress fibers were prominent in MRC-5 cell models. Use of a fluorescent actin probe, 7-nitrobenz-2-oxa-1,3-diazole-phallacidin permitted visualization of contraction of the stress fibers in the presence of MgATP and Ca2+. Of the proteins in MRC-5 cell models, only a myosin 20 Kd light chain was phosphorylated in a Ca2+-dependent manner. This Ca2+-dependent phosphorylation of the 20 Kd light chain closely corresponded with the contraction of MRC-5 cell models: 1) Both phosphorylation of the 20 Kd light chain and contraction of MRC-5 cell models were inhibited by calmodulin antagonists such as N-(6-aminohexyl)5-chloro-1-napthalene sulfonamide. 2) The threshold Ca2+ concentration for phosphorylation of the 20 Kd light chain was similar to that for contraction of MRC-5 cell models. Both were lowered by exogenous calmodulin in a concentration-dependent manner. 3) The 20 Kd light chain was thiophosphorylated by incubation of MRC-5 cell models with an ATP analogue, adenosine 5′-0-(3-thiotriphosphate) only in the presence of Ca2+. After this treatment, MRC-5 cell models lost the Ca2+-dependence for contraction. These results indicate that Ca2+-calmodulin-dependent phosphorylation of myosin 20 Kd light chain is required for contraction of MRC-5 cell models.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 21
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984) 
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 22
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 197-213 
    ISSN: 0886-1544
    Keywords: gelation ; actin ; filamin ; cytoplasm ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have compared the meniscus depletion assay and falling ball viscometry, two means of assessing the extent of gelation in actin-based systems using mixtures of actin and the actin-binding protein filamin. We examined the effect of varying the concentrations of actin and filamin in both assays. The interaction of actin and filamin was detected only above a threshold concentration of filamin. This threshold concentration was lower for falling ball viscometry than for the meniscus depletion assay at equal actin concentrations. At constant concentrations of filamin, an increase in actin concentration caused an increase in apparent viscosity measured by the falling ball assay, but a decrease in sedimentability detected by the meniscus depletion assay. The rate of sedimentation of actin was dependent on the molar ratio of actin to filamin. At each molar ratio, the sedimentation of actin was not dependent on the specific concentrations of actin and filamin used. The apparent viscosity was dependent on both the molar ratio and the specific concentrations of actin and filamin. To relate the present results to earlier studies, we examined mixtures of actin and filamin using a macroscopic assay of gelation (tube tipping assay), and polarized light microscopy. The effect of increasing filamin concentration in the four assays was compared at three actin concentrations. Mixtures of actin and filamin whose apparent viscosities were low enough to be estimated by falling ball viscometry were optically isotropic fluids that flowed out of inverted test tubes. Mixtures of actin and filamin in the range of sensitivity of the meniscus depletion assay were either viscous fluids or gels, and were either optically isotropic or anisotropic. Thus, the four assays provide different estimates of gelation. Both the meniscus depletion assay and falling ball viscometry can be used to determine relative gelation activity, but neither can be used as a quantitative assay of gelation.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 23
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 1-5 
    ISSN: 0886-1544
    Keywords: motility ; power output ; muscle ; flagella ; cytokinetic furrow ; mitotic spindle ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cellular motile systems as diverse as muscle and the mitotic spindle have been compared by their specific power output: the maximum power they develop per unit of engine volume. Striated muscles and flagella have high specific output; their performance is comparable to that of typical automobile engines. The cytokinetic furrow and the mitotic spindle have very much lower specific power output. The furrow's output is 7,000 times lower than muscle and the spindle's is 300,000 times lower. Different macromolecules have been used to generate power in systems with similar output (muscles and flagella) and, conversely, the same macromolecular motor has been used in systems with very different output (muscles and cytokinetic furrows). The common feature amid this diversity is adaptation to a particular biological role, which specific power output reflects very well. High values are found where a powerful, compact engine should be advantageous, while low values are found where precision, not power, matters most.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 24
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 469-503 
    ISSN: 0886-1544
    Keywords: cytogel ; actomyosin ; Physarum ; oscillations ; mechanics ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The contractility of actomyosin gels is the basis for a variety of cellular motility phenomena. We present here a mechanical analysis of contractile gels. By making certain hypotheses on the chemical regulation of cytogel contraction we formulate a model for the rhythmic contractions of plasmodia in the slime mold Physarum polycephalum which is in accord with a number of experimental observations.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 25
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 57-71 
    ISSN: 0886-1544
    Keywords: actin ; calcium ; coelomocytes ; ionophore ; pH ; shape transformation ; video microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We have investigated the ability of the Ca+ + ionophore A23187 to induce the transformation of petaloid sea urchin coleomocytes to the filopodial form. The response of individual cells to different media was observed with time-lapse phasecontrast video microscopy. In the presence of 1 mM CaCl2, isotonic medium containing 1-5 μM A23187 produces a similar shape transformation to that caused by hypotonic shock. Higher concentrations of ionophore (10-20 μM) induce the formation of filopodia that are thinner and less rigid than those generated by hypotonic shock or low doses of ionophore. A23187 also induces shape transformation in highly flattened cells that do not respond fully to hypotonic shock. The induction of cytoplasmic alkalinization by NH4Cl, methylamine-HCl, or the Na+ ionophore monensin does not induce shape transformation, suggesting that increased intracellular pH is not the stimulus for this process. Ultrastructural changes in cytoskeletal organization were examined in negatively stained detergent-extracted cells. Low doses of ionophore produce filopodia that are indistin-guishable from those of hypotonically shocked cells, with actin filament bundles that are straight and cohesive along their entire length. High concentrations of ionophore produce filopodia with filament bundles that branch repeatedly and splay apart near their tips, forming loops and irregular curves. These results suggest that an increase in intracellular free Ca+ + concentration acts as the trigger that stimulates coelomocyte shape transformation, but that abnormally high concentrations of intracellular Ca+ +, produced by high doses of ionophore, interfere with actin filament bundling.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 26
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 121-128 
    ISSN: 0886-1544
    Keywords: axonal transport ; ATP ; nucleotides ; saltatory movement ; dynein ; video microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In a permeabilized axon model, exogenous ATP can reactivate intraaxonal saltatory organelle movements (microscopically visible manifestations of fast axonal transport). We have studied the dependence of the reactivated movements on the ATP concentration and have also examined the nucleotide specificity of the reactivation. Organelle transport was visualized in isolated lobster giant motor axons using Nomarski optics and video microscopy. The axons were permeabilized with saponin, and movement was reactivated with ATP or other nucleotides. Some slight movement was seen with ATP concentrations as low as 10 μM. The velocity and frequency of the reactivated transport increased with increasing ATP concentrations up to about 5 mM. Movement was also reactivated by deoxyadenosine triphosphate, but not by AMP-PNP (a nonhydrolyzable ATP analogue), ADP, or AMP. Although other nucleotides (CTP, GTP, UTP, ITP) could reactivate transport, movement equivalent to that produced by 0.1 mM ATP was only seen with tenfold or greater concentrations of the other nucleotides. This pattern of specificity is consistent with the hypothesis that a dynein-like ATPase, rather than a myosin, is involved in fast axonal transport.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 27
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 137-149 
    ISSN: 0886-1544
    Keywords: anti-fluorescein ; fluorescent analog cytochemistry ; molecular cytochemistry ; microinjection ; actin ; acetamidofluorescein-actin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Fluorescent analogs of cellular components are finding increasing use in the field of cell biology. The power of this technique can be augmented by the use of antibodies specific for the fluorophore to visualize selectively the fluorescent analog at the electron microscope level. Rabbit antibodies specific for fluorescein were elicited and purified according to published methods (Lopatin and Voss [1971]: Biochemistry 10:208). Immune sera and IgG formed precipitin lines with fluorescein-labeled proteins in Ouchterlony immunodiffusion assays, and significantly quenched the fluorescence of fluorescein-labeled proteins. Immune IgG and Fab fragments decorated fluorescein-labeled actin, but not unlabeled actin, in negative-stained preparations. Anti-fluorescein IgG was used for immunofluorescent localization of fluorescein-labeled actin following microinjection of the fluorescent analog into living cells. This approach was extended to the immunoelectron microscopic localization of the injected analog at the subcellular level by the use of an electron-dense marker coupled to goat anti-rabbit IgG. Many other fluorescent probes also can be used as haptens for production of antibodies. Therefore, a general method for localizing fluorescently labeled molecules at the electron microscopic level is now available. Several other applications of anti-fluorescein antibody in studies involving fluorescent analogs are also suggested.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 28
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 76-76 
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 29
    ISSN: 0886-1544
    Keywords: fast axonal transport ; mitochondria ; membrane receptors ; cytoskeleton ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: In living tissue, membrane-bound organelles, including mitochondria, move along parallel cytoplasmic pathways. Motion is directed and tends to be confined to a single path. Deviations from this single path motion are rare. When present, however, they tend to occur at points of intersection of cytoskeletal linear elements (LE). Such intersections are relatively uncommon in intact axons and extruded axoplasm. However, we have found that such intersections can be produced in extruded preparations by shear forces directed tangential to the axoplasmic surface.We have studied the detailed behavior of mitochondria in extruded squid axoplasm. Special attention was directed to the relationship between mitochondrial shape changes and orientation of cytoskeletal LE. The most striking of these changes in shape is branching. In this process, the mitochondrion transiently assumes a triradial (three-ended) shape. This appearance may be maintained for seconds to minutes before the normal cylindrical shape is resumed by absorption of either the newly formed end or, more commonly, one of the original ends. The frequency of branching appears to be dependent on the degree of cytoskeletal organization. It becomes more common as the number of apparent intersections between cytoskeletal LE increases. Further, the formation of new ends seems to occur along paths defined by cytoskeletal elements.These observations suggest that the mitochondrial membrane is multivalent. That is, it contains multiple sites capable of interacting with the axonal force generation apparatus. Furthermore, LE in the cytoskeleton may indicate the paths along which these interactions are permissible.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 30
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 151-153 
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 31
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 231-239 
    ISSN: 0886-1544
    Keywords: pseudostereoscopy ; particle speed distribution ; velocity distribution ; fast axonal transport ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: We describe a simple method for direct visualization of the velocity distribution of particles moving against an immobile background. The technique involves pseudostereoscopic viewing of image pairs separated by an appropriate time interval in a sequential recording of the subject. Under these conditions, the positive or negative parallax arising from particle motion results in the binocular image of a particle being perceived as raised or lowered relative to an immobile background plane depending on its direction of movement, and with the degree of perceived elevation being proportional to its speed. In effect, the binocular optic axis becomes a velocity (speed) axis under these conditions. The technique is illustrated with examples of image pair sequences showing fast axonal transport in lobster and squid axons using video-enhanced differential interference contrast microscopy. However, the pseudostereoscopic method is quite generally applicable to both microscopic and macroscopic time-dependent phenomena. Particle speeds can be quantitated using standard procedures for measuring frame-to-frame particle displacements, or alternatively, by determination of parallax using stereogrammatic methods. It should be also readily adaptable for on-line monitoring of particle velocity distribution, particularly in video systems where frame buffers can be utilized to extract and present serial image pairs having any desired time separation from video-taped sequences.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 32
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 304-305 
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 33
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 305-314 
    ISSN: 0886-1544
    Keywords: cell surface motility ; axopodia ; reticulopodia ; Allogromia ; Echinosphaerium (Actinosphaerium) nucleofilum ; surf-riding ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The mechanism responsible for the energy-dependent movement of membrane components (ie, surface motility) is unknown. Recently a potentially unifying model, termed “surf-riding” [Hewitt, 1979] or “surf-boarding” [Berlin and Oliver, 1982], has been proposed to explain surface motility. Using phase-contrast light microscopy and membrane surface markers (polystyrene microspheres), we have tested the surf-riding/surf-boarding hypothesis on two protozoan systems: the axopodia of the heliozoan Echinosphaerium nucleofilum and the reticulopodial networks of the allogromiid foraminiferans Allogromia laticollaris and Allogromia sp, strain NF. Our evidence indicates that surface motility, as displayed by these organisms, does not occur by a surf-riding/surf-boarding mechanism. Previouś observations on surface motility associated with the Chlamydomonas flagellum indicate that this system is also incompatible with the surf-boarding/surf-riding hypothesis.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 34
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 403-404 
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 35
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984) 
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 36
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 405-416 
    ISSN: 0886-1544
    Keywords: cardiac muscle ; myofibril ; cell spreading ; Z bands ; alpha-actinin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cardiac myocytes were isolated from 5-6-day-old chick embryos and allowed to spread in culture. The distribution of alpha-actinin in the cells was followed for five days in culture by exposing permeabilized cells to rhodamine-labeled alpha-actinin and also by injecting the labeled alpha-actinin into living myocytes. In addition to labeling the Z bands of sarcomeres, the added alpha-actinin also labeled small particles that were usually arranged periodically in linear arrays with a spacing between particles of 0.3-2.0 μm. Actin was localized between the particles of alpha-actinin by means of fluorescein-labeled heavy meromyosin. The punctate localization of alpha-actinin was prominent in pseudopods, behind ruffles, and at the periphery of spreading cells. Long rows of particles of alpha-actinin were often parallel to one another with the alpha-actinin particles in register. These linear arrays appeared to merge laterally to form strands with broader concentrations of alpha-actinin. Other linear arrays were parallel to myofibrils in the cell and some extended outward from the ends of myofibrils. We conclude that during spreading of cardiac myocytes, myofibrils form at the cell periphery behind the extending margins of the cell, and that the aggregates of alpha-actinin found in these areas are nascent Z bands in the forming myofibrils.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 37
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 249-267 
    ISSN: 0886-1544
    Keywords: Paramecium ; trifluoperazine ; cilia ; calmodulin ; calcium ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Trifluoperazine (TFP), a drug that binds to Ca2+-calmodulin (CaM) complexes, altered swimming behavior not only in living paramecia, but also in reactivated, Triton-extracted “models” of the ciliate. By comparing the responses of living cells and models, we have ascertained that two sites of drug action exist in paramecium cilia. Swimming movements were recorded in darkfield stroboscopic flash photomicrographs; this permitted accurate quantitation of velocities and body-shape parameters. When living paramecia were incubated in a standard buffer containing 10 μM TFP, their speed of forward swimming fell over several minutes and their bodies shortened. Untreated paramecia backed up repeatedly and frequently upon transfer to a solution containing barium ions (the “barium dance”), but cells preincubated in TFP did not “dance.” Instead they swam forward slowly for long periods of time without reversing and occasionally then exhibited abnormally prolonged reversals. W7 effects on swimming mimicked low doses of TFP, and the analog W5 did not visibly alter normal swimming patterns. These results suggest that TFP induces a decrease in the intracellular pCa of living paramecia, perhaps by reducing the efficiency of a calmodulin-activated calcium pump in the cell membrane. Paramecia extracted with Triton X-100 and reactivated to swim forward (7 ≥ pCa ≥ 6) were not affected by addition of up to 40 μM TFP to the reactivation medium. We conclude that the main drug effect in living cells is probably not at the axoneme. However, at low pCa, TFP directly affected the ciliary axoneme to shift its behavior to one characteristic of a higher pCa: TFP inhibited backward swimming in models reactivated at pCa 〈 6; instead they swam forward or rocked in place. The mechanism of ciliary reversal in paramecium may therefore depend on an axonemal Ca+-sensor, possibly bound CaM, which is affected by TFP only at low pCa, as has been postulated for other types of cilia.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 38
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984) 
    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
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 39
    ISSN: 0886-1544
    Keywords: microtubule ; tubulin ; MAPs ; calcium ; mitosis ; unfertilized sea urchin egg ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Cytoplasmic tubulin purified from unfertilized sea urchin eggs self-assembles in the absence of microtubule-associated proteins (MAPs) [Suprenant and Rebhun, 1983; Detrich and Wilson, 1983] with a critical concentration for polymerization of 0.8 mg/ml at 15-18°C, a value well below the 3 mg/ml tubulin present in these eggs [Pfeffer et al, 1976]. Studies of the calcium sensitivity of unfertilized S. purpuratus (sea urchin) egg tubulin were initiated to help understand how this tubulin is maintained unassembled in the unfertilized egg. Egg microtubules, assembled at physiological temperatures (15-18°C) were depolymerized by a 100-fold lower free calcium concentration than egg microtubules assembled at the higher temperatures (25-37°C) generally used to assemble mammalian brain microtubules. The initial rate of egg microtubule assembly was much more sensitive to calcium than was microtubule depolymerization at steady state at 37°C. However, both processes were sensitive to near physiological free calcium of free calcium for depolymerization than microtubules assembled at 18°C from egg tubulin alone. While calcium regulatory MAPs have not yet been found in sea urchin eggs, the fact that brain MAPs interact with egg tubulin and regulate both its critical concentration for polymerization [Suprenant and Rebhun, 1983] and its calcium sensitivty, suggests that such regulatory molecules exist. These results suggest that sea urchin egg tubulin assembly in vivo could be controlled by variations in interacellular calcium levels acting in concert with urchin egg proteins similar in function to brain MAPs.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 40
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 387-401 
    ISSN: 0886-1544
    Keywords: bull sperm flagella ; motility ; time course ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Detailed measurements were made of the time course of the motion of bull spermatozoa. Fourier analysis of the data showed the time course to be basically sinusoidal within 2% to 3%. An asymmetry in the motion was present, resulting in a second harmonic component in the Fourier spectra of normal sperm of approximately 11% of the main component. When the energy metabolism of the sperm was inhibited or when the external viscosity of the medium was raised, the asymmetry was reduced. When the internal Mg2+ content of the sperm was lowered, the asymmetry was increased. The asymmetries and the corresponding second harmonic components in the Fourier spectra were correlated with the overall bend shape of the sperm and with the curvature of the path in which the sperm were swimming. Model calculations showed that the asymmetry could reside in either the internal active moments in the sperms or in the stiffness of the sperm fiagella.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 41
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 443-468 
    ISSN: 0886-1544
    Keywords: actin ; microfilaments ; HMM ; phagocytosis ; cytochalasin ; Paramecium ; fluorescence microscopy ; electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Using heavy meromyosin (HMM) or the fragment S1 of myosin as probes for actin microfilaments, we studied their organization in Paramecium both by fluorescence and electron microscopy.In interphasic cells, HMM decorates (a) most prominently the periphery of nascent and young food vacuoles and their route during the early phase of their intracellular transit; (b) a thin meshwork radiating from the gullet throughout the cytoplasm; (c) a small area beneath the pore of contractile vacuoles and beneath the cytoproct when open to release food residues. Most of these HMM-decorated structures are in close contact with microtubular arrays. All HMM decoration disappears in dividing cells and in cytochalasin-treated cells. In vivo, the drug immediately blocks food vacuole formation but does not affect cytokinesis, cyclosis, contractile vacuole pulsation, defecation, or nuclear movements.The data show that, as in the cells of other organisms, actin microfilaments form defined arrays that undergo physiologically controlled cycles of assembly/disassembly. These arrays contribute (at least in the phagocytotic process) to diverse types of movement: constriction, membrane fusion, and migration of food vacuoles. However, aside from their massive concentration along the phagocytotic tractus, actin microfilaments are neither major structural components of Paramecium cytoplasm nor the only cytoskeletal components ensuring motility or contractility processes.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 42
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 155-167 
    ISSN: 0886-1544
    Keywords: taxol ; microtubules ; mitosis ; mitotic spindle ; calcium ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Taxol stabilizes or promotes the assembly of microtubules. In this report we characterize the rate, extent, and reversibility of taxol stabilization of calciumlabile microtubules in isolated mitotic spindles, principally from embryos of the sand dollar Echinarachnius parma. The intense depolymerizing action of 100 μM Ca2+ was used to assess the extent of stabilization by taxol. Changes in spindle microtubule assembly were evaluated and recorded by measuring changes in spindle birefringent retardation (BR). Membrane-free mitotic spindles, isolated with a calcium-chelating, nonionic detergent buffer, were stored in an EGTA-gylcerol storage buffer to prevent microtubule depolymerization. When perfused with an EGTA-buffer without glycerol, microtubules in these isolated spindles depolymerized gradually over 60-120 min; but in isolated spindles perfused with buffer that contained 100 μM Ca2+, BR decreased by 90% within 2-5 sec. In contrast, spindles that were pretreated for 3 min with 1 μM taxol, or for about 30 sec with 10 μM taxol, lost less than 10% of their initial BR when perfused with buffer containing 100 μM Ca2+. The rate and extent of microtubule stabilization by taxol depended on both the concentration and the duration of exposure to taxol. Taxol stabilization was reversible. After a 15 min preincubation with 1 μM or 10 μM taxol then washout, stability of spindle BR to 100 μM Ca2+ decreased exponentially with a time constant of 30-60 min. Thus taxol dissociates from spindle microtubules at significant rates; taxol-stabilized microtubules are not “fixed.”
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 43
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 215-226 
    ISSN: 0886-1544
    Keywords: sperm motility ; flagellum ; axoneme ; microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Iontophoretic application of ATP to the flagellum of the demembranated hamster spermatozoon produced a planar pair of bends at the two ends of the stimulated site. During bend propagation, torsion appeared in the vicinity of the interbend in some responses such that the distal bend was twisted clockwise when viewed from the base of the flagellum. This pattern of propagation is consistent with the instantaneous configurations of free-swimming cells previously described. The technique used here establishes that the three dimensionality arises from propagation per se, and does not depend on forces developed during swimming. The rolling of both free-swimming intact and demembranated spermatozoa was examined by two-color darkground videomicroscopy and the direction of rotation was, as predicted, always anticlockwise. A hypothetical mechanism, involving differential speeds of propagation of active sliding within the active microtubule subset, is proposed to account for the observed waveforms.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 44
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 283-295 
    ISSN: 0886-1544
    Keywords: axonemal mutants ; Ca++ response ; ciliary reversal ; electrophysiology ; models ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Six mutants of Paramecium tetraurelia, which display altered axonemal responses to Ca++, are described. The mutants, designated atalantas, are impaired in their ability to swim backward when stimulated by ions or heat; instead they spin very rapidly in one place. Three mutants, ataA1-3, are completely unable to swim backward. The three lines, however, can be distinguished from one another by their forward swimming velocities. The remaining three mutants are leaky. ataB swims backward briefly when stimulated, then stops and spins in place. ataC and ataD are extremely leaky and only display the spinning phenotype at elevated temperatures. An electrophysiological analysis reveals that all six mutants have normal membrane properties, including the Ca++ inward current under voltage clamp. When the membrane is disrupted so as to allow the axoneme free access to Ca++, wild-type cells swim backward, but the mutants do not. These data indicate the site(s) of lesion in the mutants is in the axoneme or in some step linking Ca++ influx and the axoneme, not within the ciliary membrane. These mutants may be useful in investigating the role of Ca++ in the regulation of axonemal motion.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 45
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 4 (1984), S. 351-370 
    ISSN: 0886-1544
    Keywords: axon ; rate ; nervous system ; tissue culture ; cell growth ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: A new formula calculates rates of directed axonal growth (elongation or retraction) using measurements of growth cone movements. By explicitly separating changes in axonal length from other nonelongational growth cone movements, the calculated rates reflect the detailed cellular growth mechanisms more directly than previous growth measures. In addition, the formula produces three distinct parameters of axonal elongation: n, a growth step rate; s, a growth step size; and P, a probability that a growth step leads to axonal elongation. For normal and regenerating individual chick and frog axons in culture, the formula has quantitated the following differences: the axon itself can elongate more rapidly in the chick, and the axon elongates in smaller steps in the chick. The underlying dynamics of growth of regenerating axons are quite similar to normal axons, but, in the short term, regenerating axons elongate in larger steps and at a slower rate. The distribution of these new rate measurements suggests that the elongation of axons can be usefully modelled as a one-dimensional stochastic walk.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 46
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 1-19 
    ISSN: 0148-7280
    Keywords: spermatozoa ; acrosome ; fertilization ; hamster ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Adult female golden hamsters were induced to superovulate. When they were mated several hours prior to ovulation or artificially inseminated about the time of ovulation, nearly 100% of their eggs were subsequently fertilized monospermically. During the progression of fertilization when the eggs were still surrounded by compact cumulus oophorus, the contents of the ampullary region of the oviducts were collected and spermatozoa moving in the ampullary fluid, within the cumulus and on/in the zonae pellucidae of unfertilized eggs, were examined by light and electron microscopy to evaluate the status of their acrosomal caps.Most spermatozoa swimming in the ampullary fluid had apparently intact acrosomal caps, while the vast majority moving within the cumulus had distinctly modified acrosomal caps. Most spermatozoa that had passed through the cumulus and reached the zona surfaces had remnants of their acrosomal caps (“acrosomal ghosts”). When the ghosts were present around the sperm heads on the zona, the heads pivoted about a point roughly corresponding to the places where the ghosts were located. The ghosts seemed to firmly attach to the zona surfaces, then were split open by the sperm heads and left behind as the sperm heads advanced into the zona. A few spermatozoa on the zona surfaces had no acrosomal ghosts (at least not detectable by light microscopy). In this case, the sperm head pivoted about either the inner acrosomal membrane or the equatorial segment of the acrosome. In no instance were spermatozoa with intact acrosomal caps found on zona surfaces.We infer from these observations that most spermatozoa in vivo initiate their acrosome reactions while they are advancing through the cumulus. When they arrive at the zona surfaces, acrosomal ghosts are generally present on the sperm heads. These ghosts appear to hold sperm heads to zona surfaces as well as to restrict the direction of advancement of sperm head through the zona. In a minority of cases, ghostless spermatozoa reach the zona surfaces. As these spermatozoa appear to be able to penetrate the zona successfully, structures other than the acrosomal ghost (ie, the inner acrosomal membrane and the plasma membrane over the equatorial segment of the acrosome) may also attach to zona surfaces before spermatozoa penetrate into the zona.
    Additional Material: 19 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 47
    ISSN: 0148-7280
    Keywords: spermatozoon ; zona pellucida ; scanning electron microscope ; hamster ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Hamster spermatozoa are able to fertilize a high percentage of zona-intact hamster oocytes when they are preincubated for 2 hr in a chemically defined medium. From this time on, the longer the preincubation time the lower the percentage penetration. Spermatozoa preincubated for 6 or more hr are unable to cross the zona pellucida, retaining however their ability to fuse with zona-free hamster oocytes.Zona-intact hamster oocytes, as described above, were observed with the scanning electron microscope. When the oocytes were inseminated with spermatozoa preincubated for 1 to 5 hr the outer surface of the zona showed the penetrating spermatozoa and the sperm tracks made by those that failed to cross it. With longer preincubation times no penetrating spermatozoa were observed, and very few sperm tracks were present on the outer surface of the zona.Control experiments showed that neither eggs, spermatozoa, nor fertilization were affected by the medium recovered after long preincubations.These results show that care should be taken regarding the preincubation time when using the in-vitro fertilization technique.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 48
    ISSN: 0148-7280
    Keywords: rat ; zona-binding ; fertility ; epididymis ; spermatozoa ; testosterone ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Rat spermatozoa from the proximal caput, the proximal corpus, the middle corpus, and the distal cauda epididymidis were examined for their ability to bind to the zona pellucida after a 1-, 2.5-, or 4.5-h incubation at 34°C with rat eggs in cumulus. Caput spermatozoa did not bind to the zona after 1, 2.5, or 4.5 h of incubation. Corpus spermatozoa did bind to the zona, but the percentage of eggs with bound spermatozoa and number of bound spermatozoa per egg increased with the length of incubation. Cauda spermatozoa bound readily to the zona pellucida, and their zona binding ability did not change with longer incubations. It thus appears that rat spermatozoa gradually acquire the ability to bind to the zona pellucida in the corpus epididymidis.The zona-binding capacity of cold immobilized cauda spermatozoa, defined as the percentage of eggs with bound spermatozoa, increased with the number of spermatozoa incubated and reached a plateau characteristic of the endocrine status of the animal. After castration, zona-binding ability is progressively lost from day 3 until day 10 where it is nil. Testosterone supplementation maintains zona-binding ability to control levels. Similarly, fertilizing ability declines from day 5 after castration until day 10. Testosterone prevents this loss of fertilizing ability. It thus appears that the development of zona-binding ability during epididymal transit is, like the development of fertilizing ability, under androgen regulation.The close correlation between the onset of fertilizing ability and zona-binding ability during maturation, the loss of fertilizing ability and zona-binding ability after castration, and the recovery of both fertilizing ability and zona-binding ability with testosterone treatment suggests that the androgen-dependent development of zona-binding ability is an important component of the acquisition of sperm fertilizing ability during epididymal transit.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 49
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 45-54 
    ISSN: 0148-7280
    Keywords: porcine zona pellucida ; solubilization ; Li-3,5-diiodosalicylate ; electron microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Isolated porcine zonae pellucidae were investigated using transmission electron microscopy. It was found that the fine structure of the zona is not homogenous. The region near the oocyte consists of a more tightly packed micellar structure than the structure near the external surface. However, no clear boundary between the two structural features could be detected. The assumption that the molecular structure of the external and internal surface of the zona is not the same is substantiated by the finding that antibodies against the whole zona structure react apparently only with the more loosely bound structure on the external surface. This effect is attributed to differences in the spacial arrangements of the micellar structures rather than to differences in chemical composition. Solubilization of the zona results in a reorientation of the otherwise randomly interconnected structure. At lower Li-3,5-diiodosalicylate concentration (0.05 M) the fibrils seems to expand so that the individual fibers lie almost parallel to each other. At a higher Li-3,5-diiodosalicylate concentration (0.2 M) the individual micelles begin to break up from the zona surface, while at a still higher concentration (0.3 M) the rigid structure of the zona is completely solubilized. In the latter case no residual material could be detected in the sediment following high speed centrifugation of the mixture. These electron microscopic results correlated with the protein concentrations in the supernatant indicating that the maximal protein content (35 ng/zona) is obtained at 0.3 M or higher Li-3,5-diiodosalicylate concentrations.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 50
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 99-114 
    ISSN: 0148-7280
    Keywords: cyclic AMP ; epididymal spermatozoa ; sperm motility ; sperm maturation ; reactivation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Hamster spermatozoa from the caput and cauda epididymides were demembranated with 0.04% Triton X-100 and reactivated with 1 mM ATP. Motility parameters were analysed by video recording and stroboscopic photography. In the absence of added cAMP, reactivated cauda sperm showed percentage motility and forward swimming patterns similar to those of intact cells, but velocities were lower. When 2 or 20 μM cAMP was present, the velocities were increased but there was no effect on beat frequencies or percentage of forward progressing sperm. Cyclic AMP also markedly increased the percentage of cauda sperm which at first displayed nonprogressive “looping” movement. Addition of cAMP to the reactivation medium greatly improved the otherwise feeble and irregular motility of the demembranated caput sperm by increasing the percentage motility and beat frequencies of nonprogressive cells. It also induced forward motility with beat frequencies and velocities similar to cauda sperm reactivated in the absence of cAMP, but looping was never seen, indicating a change in the flagellar apparatus with maturation. The time required for the exhibition of the cAMP effects was reduced when caput sperm were reactivated in extracts of another previously maximally reactivated caput sperm preparation. The results suggest the production of some potent compound(s) by the axonemes for the manifestation of the cAMP effects.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 51
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 129-129 
    ISSN: 0148-7280
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 52
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 183-195 
    ISSN: 0148-7280
    Keywords: flagellar wave ; human spermatozoa ; microcinematography ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Microcinematographic analysis (50 frames/sec) of the movement of 57 ejaculated human spermatozoa showed a heterogeneity of the flagellar parameters (velocity of the wave development (Vd), velocity of the wave propagation (Vc), beat frequency) corresponding to that of head trajectories (progressive velocity and amplitude of the lateral head displacement). According to our results the interdoublet sliding velocity might control the progressive velocity of the spermatozoa through the wave propagation velocity. The presence of the principal bend on the proximal part of the flagellum (20 μm) might inhibit the initiation of a new wave. The complex relation existing between Vc and Vd seems to indicate that the two velocities are partly independent of one another.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 53
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984) 
    ISSN: 0148-7280
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 54
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 253-260 
    ISSN: 0148-7280
    Keywords: calmodulin ; embryonic development ; mitosis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Two-cell mouse embryos were incubated in the presence of calmodulin inhibitors to determine their effect on embryonic development to the blastocyst stage. Calmodulin, a Ca2+-dependent regulatory protein, has been localized in the cytoplasm and has been implicated in regulation of many cellular events, such as mitosis. Several concentrations of either commercial or synthesized calmodulin inhibitors were tested. Several phenothiazine sulfoxide derivatives were more effective than the three naphthalene sulonic acid derivatives tested; 2-chloro-10-aminopropyl phenothiazine and 10-aminopropyl phenothiazine were the most potent phenothiazines to inhibit embryonic development at the two-cell stage. The interesting aspect of this study is that phenothiazine sulfoxide derivatives are not potent inhibitors of calmodulin, however, they were successful in inhibiting embryonic development. Potent inhibitors of calmodulin apparently did not penetrate the embryonic membranes because they had no effect.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 55
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 303-327 
    ISSN: 0148-7280
    Keywords: spermatogenesis ; Actinia fragacea ; ultrastructure ; testicular cyst ; trophonema ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Spermatogenesis in the sea anemone Actinia fragacea takes place in numerous testicular cysts located in the mesoglea of the gonads. Prospermatogonia arise among the bases of the gonadal epithelial cells bordering the mesoglea, and later migrate into the mesoglea to establish the cysts. The prospermatogonia arise singly, but soon most are found as small groups within the endoderm. They are small cells, 6-7 μm in diameter, and have relatively large nuclei with a single nucleolus. Their cytoplasm is dense, and contains dense bodies and nuage material as well as Golgi, mitochondria, and individual cisternae of endoplasmic reticulum. Each prospermatogonium bears a flagellum, originating in a groove or channel in the cytoplasm.A small proportion of prospermatogonia enter the mesoglea singly, but most migrate as elongate groups or “slugs” of cells. As they enter, the groups often become constricted into hour-glass shapes, and they become covered by the endodermal basal lamina. During the later stages of entry, the last part of the group to enter retains contact with the bases of the epithelial cells, which are dragged into the mesoglea behind the germ cells. This contact between germ cells and endoderm persists throughout spermatogenesis and prevents closure of the mesoglea behind the group. The endodermal cells involved begin specialization to form the trophonema. Once entry is complete, the groups enlarge rapidly to form the testicular cysts. A small number of germ cells appear to remain behind in the endoderm after most have entered the mesoglea, and the possible significance of these cells is discussed.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 56
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 351-358 
    ISSN: 0148-7280
    Keywords: behavior ; mated ; mice ; female ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Mated C57BL/6J females experienced in food-motivated maze running were found to make more choices and choose more correctly than virgins. The differences correlated with the receipt of spermatozoa and prior pseudopregnancy. Pregnancy, active pseudopregnancy, and male-female social interactions did not appear to be required determinants. The biologic ramifications of mating in mice may extend beyond the fusion of sperm and egg and the induction of hormonal changes that regulate the earliest stages of pregnancy.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 57
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 359-359 
    ISSN: 0148-7280
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 58
    ISSN: 0148-7280
    Keywords: rat ; zinc-deficient ; sperm ; dense fibers ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Zinc is required for spermatogenesis in mammals and is concentrated in the dense outer fibers of the sperm tail, where it is associated with cysteine-rich protein. To investigate the effects of marginal zinc deficiency upon dense fiber formation and upon sperm quality in general, weanling Sprague-Dawley rats were administered a commercial low-zinc diet, supplemented with phytate, for approximately 60 days, and were compared with controls fed the same diet plus 50 ppm zinc in their drinking water. The following characteristics of the zinc-deficient rats were significantly lower than in the controls: body weight, testis weight, epididymis weight, seminal vesicle weight, sperm content of the cauda epididy-midis, sperm motility, testis zinc, and hair zinc. By contrast, the levels of sperm zinc and sperm sulfhydryls were the same in the zinc-deficient and control rats. The zinc-deficient rats displayed a highly variable spectrum of sperm defects, which included decapitation, disorganized and redundant tail elements, and superfluous cytoplasm. However, abortive dense fiber development was only rarely observed. Apparently, even when availability of zinc is limited and reduced sperm production ensues, elaboration of dense fibers rich in zinc and sulfhydryls continues to be obligatory for the completion of spermiogenesis.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 59
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 409-424 
    ISSN: 0148-7280
    Keywords: Crustacea ; crab ; cortical reaction ; ER-vesicle differentiation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: During the cortical reaction, Carcinus maenas eggs successively released a fine granular material and a massive amount of ring-shaped elements that subsequently formed most of the fertilization envelope. The ring-shaped elements came from egg cortical vesicles and, owing to their striking morphology, acted as naturally occurring markers in ultrathin sections, which permitted us to understand the pathway of their intracellular transport. In this respect it was established that the ring-shaped elements and their enclosing vesicles originated in the endoplasmic reticulum both in ripe oocytes and early fertilized eggs maintained under in vitro conditions. The intracellular transport pathway of the endoplasmic reticulum-derived vesicles seemed to bypass the Golgi apparatus. Accordingly, the ring-shaped elements appeared to be released by direct exocytosis from the endoplasmic reticulum system.Finally, a tentative scheme of oocytes functioning is suggested for crustacean decapods, based on the remarkable similarities between the structure and ER origin of the ring-shaped elements involved in the cortical reaction and the disc-shaped granules traditionally considered as endogenous yolk precursors. The scheme implies that the oocyte ER system might produce a precursor common to the cortical reaction exudate and to the endogenous yolk, in the form of the ring- or disc-shaped elements.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 60
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 9-19 
    ISSN: 0148-7280
    Keywords: fertilization ; polyspermy ; sea urchin eggs ; sperm peroxidase ; anti-inflammatory drugs ; cyclooxygenase ; prostaglandins ; arachidonic acid cascade ; indomethacin ; flufenamic acid ; meclofenamate ; aspirin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Sea urchin eggs are known to release H2O2 during the cortical reaction at fertilization to help prevent polyspermy by inactivating excess sperm in the vicinity. This process resembles the peroxidatic killing of bacteria by phagocytic leukocytes during inflammation. Associated with these reactions in leukocytes, arachidonic acid is released from phospholipids and can be oxidized via the cyclooxygenase pathway to produce prostaglandins. Nonsteroidal anti-inflammatory drugs (NSAID) that are cyclooxygenase inhibitors in somatic cells were used to determine whether Arbacia punctulata and Strongylocentrotus purpuratus eggs use these processes to help prevent polyspermy. The potent cyclooxygenase inhibitor indomethacin causes a dose (10-100 μM) and sperm density dependent induction of polyspermy if added before the egg completes the cortical reaction. It does not retard elevation of the fertilization envelope and does not promote polyspermy by protecting sperm from peroxidatic inactivation by egg-derived H2O2. Other potent cyclooxygenase inhibitors, flufenamate and meclofenamate, also induce polyspermy at 10-60 μM. Aspirin, a weak cyclooxygenase inhibitor in somatic cells, does not cause polyspermy at 5 mM. These findings provide evidence that prostaglandins or other cyclooxygenase-derived metabolites may help assure monospermic fertilization in sea urchins.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 61
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 57-66 
    ISSN: 0148-7280
    Keywords: Lysosomal hydrolases ; uterus ; ovary ; oviduct hamster ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Changes in the total protein content and the activities of lysosomal hydrolases (arylsulfatase, acid phosphatases, β-glucuronidase, β-N-acetylhexosaminidase, α-L-fucosidase, and β-galactosidase) of the hamster genital tract during the 4 days of estrous cycle and in hormonally superovulated hamsters were measured. Levels of lysosomal hydrolases in uteri and uterine fluid changed significantly during the cycle. Similar changes were observed in uterine wet weight and uterine proteins. The pattern of enzyme activities in both the ovary and the oviduct were different from those in uteri. In the ovary, most enzyme activities and the total protein concentration remained elevated after ovulation. Protein concentration and enzyme activities were significantly higher in the ovary, oviduct, and uteri of superovulated hamsters as compared to controls.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 62
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984) 
    ISSN: 0148-7280
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 63
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 107-118 
    ISSN: 0148-7280
    Keywords: Rat ; fertilization ; in vivo ; in vitro ; topography ; egg ; actin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The surface topography of the rat egg was examined during fertilization in vitro and in vivo. Using phase optics, 348 in vitro fertilized and 50 in vivo fertilized eggs were continuously monitored throughout the 7-hour period of sperm incorporation. A myriad of different surface configurations were seen, with each egg exhibiting one or more of the following changes. A small number of eggs (4-6%) formed surface elevations over the sperm head after its detachment from the flagellum, 15-30 min after sperm-egg fusion; 1 to 1.5 hr after fusion, 40-50% of the eggs produced the so-called incorporation cone, a prominent surface elevation over the decondensing sperm nucleus. The vast majority of eggs (74-82%) formed surface elevations over the proximal tip of the flagellum 2-3 hr after sperm-egg fusion. These had no association with the decondensing sperm nucleus. A few eggs (11-12%) exhibited multiple protrusions that were distributed randomly about the egg surface, whereas 14-20% did not manifest any surface elevations and remained spherical throughout the sperm incorporation period. Regardless of the type of surface change, all of the eggs resumed a spherical shape by the time sperm incorporation was complete. These observations are in contrast to the conclusions by previous authors that formation of the so-called incorporation cone over the decondensing sperm nucleus is a ubiquitous event.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 64
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 153-163 
    ISSN: 0148-7280
    Keywords: mouse ; sperm ; egg ; sperm plasma membrane ; in vitro ; binding ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: We have studied the molecular mechanisms of gamete interaction in vitro in the laboratory mouse, Mus musculus. In particular, we were interested in whether this interaction is similar to a lectin-hapten-mediated process. Inhibition of sperm-zona binding was examined using various concentrations (.25 mM to 50 mM) of different sugars (sialic acid α-methylmannose, glucose, fucose, galactose, and N-acetyl-glucosamine). Sperm-zona binding was significantly decreased when eggs were pretreated with 10 mM of sialic acid or α-methylmannose but not by other sugars tested. Furthermore, treatment of capacitated sperm with neuraminidase destroyed their ability to bind and fertilize eggs. We have also used a specific lectin for sialic acid from the horseshoe crab (Limulus polyphemus) to agglutinate mouse sperm. The lectin (.120 ng/ml) mediated agglutination of mouse sperm (105 sperm/ml) was routinely observed to increase from a 10% agglutination immediately following their isolation from the epididymis to 100% agglutination 90 minutes later. Collectively, these results suggest the appearance of specific sugar moieties on the surface of the sperm plasma membrane which, in this particular species of mouse, are sialylated glycoproteins acting as ligands for specific receptors on the surface of the egg. These are the first data to indicate that sperm-egg recognition and attachment is a lectin-hapten-mediated process in the mouse.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 65
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 197-205 
    ISSN: 0148-7280
    Keywords: sperm-egg attachment ; acrosome-intact sperm ; zona-free oocyte ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The attachment of acrosome-intact mammalian sperm to zona-free hamster vitelli has been investigated using light and electron microscopy. Uncapacitated sperm from hamsters, stallions, bulls, rabbits, and humans can attach firmly to the oocyte surface by means of microvillus processes. The general appearance of such attachments mimics the events seen during the interaction of acrosome-reacted sperm with the oolemma. Very close, junction-like connections develop between apical portions of sperm and oolemma after initial attachment, but no evidence of sperm penetration was observed. Significant species differences were noted with respect to the avidity of the sperm-egg interaction. Bull, horse, and rabbit sperm showed a high degree of attraction for vitelli; hamster and human sperm interácted at a lower level. Thus, in the species tested, an acrosome reaction is not a prerequisite for sperm attachment to the zona-free oolemma.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 66
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 221-229 
    ISSN: 0148-7280
    Keywords: oocyte ; in vitro maturation ; blastocysts ; sheep ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The hypothesis that follicle cells play a central role in endowing the oocyte with developmental competence during maturation has been tested in coculture studies. Oocytes and follicle cells in various combinations were cultured for 24 h with gonadotrophins and estrogen in a nonstatic culture system. Developmental competence was assessed by transfer of oocytes to inseminated receipient ewes followed by embryonic examination 12 days later or at parturition.Denuded and corona-enclosed oocytes resume meiosis in culture but remain immature and developmentally incompetent. By contrast, oocytes supported by the cumulus and underlying granulosa (cumulus-oocyte complexes) undergo full maturation and normal subsequent embryonic development (42.6% to embryos). Addition of supplementary follicle cells during culture (5 × 106 cells/ml medium) is without beneficial effect on denuded oocytes. However, supplementary cells confer competence on corona-enclosed oocytes (37% to embryos).A dual cellular requirement for full maturation involving both cell numbers and some direct cell-oocyte contact is highlighted by our experiments. The results demonstrate further that the nonstatic system provides a simple but reliable method of producing large numbers of fully matured oocytes for both research and clinical purposes.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 67
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 239-251 
    ISSN: 0148-7280
    Keywords: acrosomal ; membranes ; antisera ; agglutination ; immobilization ; sperm concentration ; zona pellucida ; enzymes ; mating ; sterility ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Rabbits were immunized against their alloantigens extracted from the sperm acrosome. The sequential method of extraction, first by MgCl2 then by detergents, provided the plasma and outer acrosomal membranes and their contents in the first step and the inner acrosomal membrane and its components in the next step. Both groups of antigens appear to have produced monospecific antisera. The MgCl2 extract antiserum lost its sperm immobilization and agglutination activities on absorption to its antigen. The detergent extract, under similar treatment, remained unaffected. Therefore, the agglutination and immobilization factors resided on the plasma membrane. The decrease in sperm concentration suggested that the immunogen affected the germinal epithelium. The reduction in the semen volume and seminal enzymes seems to indicate that the accessory sex glands were also affected by the treatment.The antiserum blocked the dissolution of the hamster and rabbit zona pellucida by the MgCl2 extract. The normal serum had no such effect. Both the normal and immune sera inhibited acrosin equally well while the antisera inhibited other proteinases, arylsulfatase, and β-N-acetylhexosaminidase to a significantly greater extent. Immunized rabbits failed to impregnate females as long as the antibody titer remained high. As the titer declined these animals became fertile and the females delivered normal litters.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 68
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 287-302 
    ISSN: 0148-7280
    Keywords: goat ; semen ; capacitation of spermatozoa ; acrosome reaction ; bulbourethral secretion ; seminal vesicular secretions ; electron microscopy ; colloidal gold ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The balancing effects of bulbourethral gland secretion (BUS) and of seminal vesicle secretion (SVS) on goat semen quality were previously demonstrated. In the present study, electron microscope observations revealed a high frequency of spermatozoa with a reacted acrosome among spermatozoa from cauda epididymis exposed to BUS in the presence of milk. This frequency was significantly reduced when SVS had been added either before or after BUS. No reacted acrosome was observed in the absence of milk. All mount spermatozoa were incubated with milk or SVS or BUS or combinations of the three materials labeled with colloidal gold. SVS attached specifically on the plasma membrane covering the anterior part of the acrosome, whereas BUS spread all over the sperm head. Milk attached on the anterior half of the sperm head only when BUS was present in the sperm environment. It is concluded that BUS plays an active role in the induction of the acrosome reaction in the presence of milk and that SVS counteracts this role.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 69
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 329-338 
    ISSN: 0148-7280
    Keywords: cortical granule reaction ; phospholipase A2 ; quinacrine ; sea urchin ; fertilization ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Fertilization of the sea urchin egg involves an exocytotic event known as the cortical granule reaction (CGR). In many cell systems, phospholipase A2 is implicated in regulation of the secretory event. Indirect evidence suggests that phospholipase A2 mediates the CGR; however, there has been no direct demonstration of phospholipase A2 activity in the sea urchin egg. We report here evidence of phospholipase A2 activity in egg homogenate of the sea urchin Lytechinus pictus. The enzyme was calcium-dependent and had a pH optimum near the intracellular pH of the unfertilized egg. Neither exogenous calmodulin nor trifluoperazine had any apparent effect on enzyme activity. Quinacrine, a phospholipase A2 inhibitor, blocked the enzyme activity in the egg homogenate. In intact eggs, quinacrine blocked the CGR in a dose-dependent, egg-concentration-dependent manner. The inhibitory effect of quinacrine on the CGR could not be overcome by the phospholipase A2 activator melittin or by the calcium ionophore A23187. Quinacrine did not inhibit sperm-egg binding or sperm incorporation. These results lend further support to the hypothesis that phospholipase A2 is involved in the CGR.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 70
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 387-397 
    ISSN: 0148-7280
    Keywords: oocyte ; meiosis ; sperm-oocyte interaction ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Immature and ovulated hamster oocytes were studied with the scanning electron microscope. Immature oocytes at the germinal vesicle stage have their surface uniformly covered by microvilli. When meiosis has progressed to the first meiotic metaphase the overlying surface shows the differentiation of a circular area 19 μm in diameter with a low density of microvilli. Later, from this region the first polar body emerges, and the oocyte surface at the point from which it was extruded shows a cluster of cytoplasmic, conical projections. When the zona-free oocytes are cultured at 37°C for 5 minutes these projections disappear and the oocyte surface at that point becomes smooth. However, when the oocytes remain in the oviduct for several hours after ovulation these projections remain unchanged. The in vitro interactions of capacitated hamster sperm with the immature oocyte was always seen at microvillus surfaces and never associated with the differentiated regions.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 71
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 399-408 
    ISSN: 0148-7280
    Keywords: sperm ; fertilization ; decondensation ; nuclear protein ; mouse ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Zona-free hamster eggs have been fertilized in vitro with boar spermatozoa in a medium enriched by arginine-3H and the sites of localization of newly synthesized arginine-3H-labeled proteins have been investigated using fine-structure autoradiography. It was confirmed that such proteins are synthesized during fertilization and that they accumulate to a notable degree in decondensing sperm chromatin as well as in the chromatin of the female pronucleus and also of the second polar body. A similar process did evidently take place also in defective pronuclei, characterized by a core of a still condensed chromatin and by remaining nuclear membrane. In such male pronuclei the highest concentration of the label was seen just on the border of the condensed chromatin, on the expected site of nuclear protein exchange. It is supposed that, at least in this experimental system, any morphologically detectable sperm decondensation is accompanied immediately by a shift from sperm basic nuclear proteins to other nuclear proteins.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 72
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 373-396 
    ISSN: 0148-7280
    Keywords: fish spermatozoa ; comparative spermatology ; Cyprinidae ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The spermatozoa of seven fishes belonging to Cyprinid family are examined. They have no acrosome, like all Teleost fishes, a spheroidal or slightly elliptic nucleus, always eccentrically placed on the tail, two variously oriented centrioles, and a postnuclear cytoplasmic region of various size that contains some mitochondria (2 to 10) and surrounds a periaxonemal postnuclear canal. The tail is of moderate length (from 36 to 60 μm) and contains a “9 + 2” axoneme: both dynein arms are present. Comparative examination of the spermatozoa in the seven species shows that significant differences occur among them, even when they belong to the same genus. These concern the tail length; the position of the centrioles, the proximal with respect to the central one and with respect to the nucleus; the number of mitochondria, which is in relationship to the depth of the postnuclear canal. In the uniform general pattern of the ultrastructure of the Cyprinid spermatozoa, each species is characterized by a particular organization of the sperm organelles; in this respect, the two species examined by us, Leuciscus cephalus and souffia, are more closely related, even if easily recognizable one from the other. From a phylogenetic point of view, the comparative spermatology of the Cyprinid fishes suggests that the mitochondrial number is a good character, which enables us to order them in a phylogenetic arrangement.
    Additional Material: 40 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 73
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 423-432 
    ISSN: 0148-7280
    Keywords: lectins ; germ cells ; gametogenesis ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Fluorescent lectins were used to study the chemical nature of carbohydrate moieties present on the surface of female and male germ cells isolated from mouse gonads during fetal and early posnatal development. Concanavalin A (ConA), lens culinaris agglutinin (LCA), ricinus communis agglutinin (RCAI) and wheat germ agglutinin (WGA) bound intensely to the germ cell plasma membrane at all stages studied. Other lectins such as ulex europaeus agglutinin (UEAI) and agglutinin (SBA) did not bind or bound moderately (SBA to female germ cells only).Distinct developmental-related changes were observed when female germ cells were labeled with fluorescein-conjugated peanut agglutinin (PNA) or dolichos biflorus agglutinin (DBA). DBA and PNA binding was absent or weak in fetal female and male germ cells, but became intensely positive in oocytes in the immediate postnatal period. The percentage of oocytes stained with DBA increased during the first three days after birth, and from day 3-4 onwards all oocytes were strongly labeled.I suggest that these changes in lectin binding reflect changes in biochemical structure of the oocyte surface related to differentiative events occurring in the mouse ovary immediately after birth.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 74
    ISSN: 0148-7280
    Keywords: bull sperm ; cell fractionation ; differential centrifugation ; centrifugal elutriation ; cAMP-dependent protein kinase ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The distribution of the cAMP-dependent protein kinase activity in bull ejaculated sperm has been investigated. This activity proved to be mainly present in a soluble form inside the cell. Sperm fractionation into heads and flagellar fragments, using differential centrifugation or centrifugal elutriation, has shown that the particulate cAMP-dependent protein kinase activity was mainly associated with the flagellar structures. A much activity was shown to be associated with the head fraction. Some activity could also be detected in the purified plasma membrane fraction.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 75
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 115-125 
    ISSN: 0148-7280
    Keywords: acrosome reaction ; fertilization ; sea urchin ; spermatozoa ; surfactants ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The effects of seven surfactants on spermatozoa of the sea urchin, Hemicentrotus pulcherrimus, were studied. All these surfactants induced the acrosome reaction and inhibited the fertilizing capacity of spermatozoa. There was a statistically significant correlation between the concentrations that induce the acrosome reaction and inhibit fertilization. The critical micelle concentrations (CMC) of surfactants in sea water were almost even and these values, which are inherent physical properties of surfactants, did not provide a direct measure of their inhibitory effect of fertilization. Among seven surfactants, p-menthanyl-phenol polyoxyethylene (8.8) ether (TS-88) with a characteristic hydrophobes was the most potent both in the induction of acrosome reaction and in the inhibition of fertilization. Various ethylene oxide adducts to p-menthanyl-phenol were also tested for the purpose of comparison. It is suggested that the effects of surfactants on sea urchin spermatozoa at low concentrations reflect their activity associated with the hydrophobic group inherent in each surfactant.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 76
    ISSN: 0148-7280
    Keywords: nonovulatory follicle ; oocyte ; cumulus ; RNA ; protein ; human ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Human nonovulatory oocyte-cumulus complexes were obtained from large antral follicles 34 h after the injection of hCG. Their ultrastructure, RNA and protein synthesis, and the ability of oocyte maturation and subsequent fertilization in vitro were the subject of this study. The oocyte nucleus was situated in the cell periphery, possessing one or two dense nucleoli. Intranucleolar vacuoles were sometimes present. Mitochondria and smooth endoplasmic reticulum were the most abundant cytoplasmic structures. The number of cortical granules was rather low. Cumulus cells showed responsiveness to exogeneous hCG/endogeneous LH stimulation as morphologic signs of the oocyte-cumulus uncoupling and of the early luteinization. Furthermore, the oocytes were capable of meiotic maturation in vitro, and following subsequent in vitro insemination the majority of them were penetrated by spermatozoa. However, polyspermy was detected in most cases, and cleavage was not achieved. A developmental defect of nonovulatory oocytes was suggested by an extremely low level of RNA synthesis while continuing active protein synthesis by nonovulatory oocytes was demonstrated. In contrast, the associated cumulus cells synthesized both RNA and protein, suggesting that the majority of granulosa cells of the nonovulatory follicles was probably unaltered. It is hypothesized that the development of nonovulatory follicles after induction of ovulation might reveal the developmental pattern which would lead, in some cases, to ovulation of nonviable human oocytes both in stimulated and natural cycles.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 77
    ISSN: 0148-7280
    Keywords: follicular fluid ; seminal plasma ; focusing ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A thin-layer electrofocusing method has been developed for the separation of proteins in human follicular fluid, seminal plasma, and blood plasma/serum. The method has a number of unique features. It is simple and rapid, and it produces distinct, undistorted bands that can be readily quantitated. Any samples solubilized by standard methods can be analyzed, and it can be adapted to favor specific regions of the pH spectrum. The gels used are composed of agarose and sorbitol, and they are formed between a plastic template and a Mylar film. Sample volumes ranging from 0.5 to 5 μl can be used. Protein separation is usually completed in 30-40 min at constant power of 1 or 1.5 W. The use of low power ensures that little heat is generated during the run and hence only minimal temperature control is needed. Carbon rod electrodes are a special feature as they allow the inverted gel to rest in direct contact with the electrodes, eliminating the necessity for electrode solutions. The inverted gel position allows fluid to drain from the surface of the gel and so prevents distortion of protein patterns. This overcomes the problems inherent in conventional horizontal electrofocusing of unpurified biologic fluids such as plasma, follicular fluid, and seminal plasma. Rapid protein staining is carried out with fixed and dried gels. The excellent resolution and the lack of distortion make this method suitable for reliable quantitative analysis of differences between samples by means of laser beam densitometry. This has enabled us to assess differences in specific follicular fluid proteins between individual follicles in the human, and to correlate these differences with fertilizability and cleavage potential of oocytes derived from such follicles.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 78
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 231-237 
    ISSN: 0148-7280
    Keywords: superovulation ; ovulation ; eggs ; hamster ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Superovulated hamster eggs obtained by injections of PMSG on day 1 (the day of ovulation) and hCG on day 3 (2 days before expected day of next ovulation) have been used widely for assessing the fertilizing capacity of spermatozoa of the homologous as well as heterologous species. The developmental ability of these eggs was assessed by transferring them to host females (recipients) that had ovulated and mated naturally. The proportion of transplanted eggs developing into normal fetuses and young was the same regardless of whether the eggs had been collected from superovulated or naturally ovulating donors. The young originating from superovulated eggs were normal in that they grew at a normal rate and produced normal progeny. It may be concluded that the precociously superovulated eggs were as normal as the control (naturally ovulated) eggs. Thus, the use of precociously superovulated hamster eggs in evaluating the fertilizability of spermatozoa is justified.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 79
    ISSN: 0148-7280
    Keywords: mouse spermatozoa ; Robertsonian chromosomes ; DNA content ; sperm aneuploidy ; genital tracts ; prezygotic selection ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The fate of morphologically normal but chromosomally abnormal spermatozoa derived from mice with variable degrees and complexity of Robertsonian heterozygosity was studied at different sites along the male and female genital tract by Feulgen-DNA measurements. In addition, the percentage frequencies of morphologically abnormal spermatozoa in transit along the male and female genital tracts were studied.It was found that during transit from the epididymis to the vas deferens the distribution of the Feulgen-DNA contents of morphologically normal spermatozoa changed: Spermatozoa with chromatin with the extremely low or high Feulgen staining intensity disappeared. The percentages of morphologically abnormal sperm cells did not change at these levels. In the female genital tracts, the distribution of Feulgen-DNA content of morphologically normal spermatozoa did not show significant changes. This indicates that spermatozoa are able to reach the fallopian tube in spite of gross genome unbalance. There is evidence that unbalanced spermatozoa take part in the fertilization process, producing abnormal zygotes subject to postzygotic loss. Conversely morphologically abnormal spermatozoa were preferentially lost before they reached the fallopian tube, suggesting they had been eliminated prezygotically.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 80
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 261-272 
    ISSN: 0148-7280
    Keywords: fertilization ; cumulus ; oocyte ; sperm ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The structure of the hamster oocyte-cumulus complex (OCC) has been analyzed to help understand how mammalian sperm penetrate the investing coats of the oocyte. At ovulation, oocytes of most mammalian species are surrounded by a zona pellucida, corona radiata, and cumulus layer. Cells of the cumulus and corona radiata are separated by an extracellular matrix (ECM) that contains hyaluronic acid. In hamsters, the diameter of mature follicular OCCs is 0.61 ± 0.12 mm, whereas in freshly ovulated OCCs in culture medium it is 0.78 ± 0.15 mm. This indicates the OCC expands at or after ovulation. The corona radiata is 1-4 cell layers deep, and corona radiata cells are closely packed (center-to-center distances between adjacent cells in follicular OCCs averaged 14 ± 3 μm). The cumulus layer is 5-8 cell layers deep, and intercellular spaces are much larger (center-to-center distances between adjacent cumulus cells in follicular OCCs averaged 50 ± 20 μm). An ovulated OCC has an approximate volume of 248 × 106 μm3 and was estimated to contain approximately 5,700 cells. Studies with stretched OCCs show that ink particles can readily penetrate the extracellular spaces of the cumulus and corona radiata layers and interact with the ECM, staining it black. At the periphery of the OCC, the ECM appeared discontinuous and formed “cords” containing cumulus cells, whereas closer to the corona radiata the matrix completely filled intercellular spaces. Ink penetrated the corona radiata, but the ECM was difficult to visualize because of the close packing of cells in this layer. Our observations on unfixed OCCs show that cell packing becomes more dense proceeding from the periphery of the OCC to the zona pellucida and that the ECM at the periphery differs from the matrix deeper in the OCC. These data suggest that an incoming sperm would find penetration of the investing coats to increase in difficulty (that is physical resistance would increase) as it got closer to the oocyte. We have also examined the effects of processing for microscopy on the structure of the OCC. Both standard fixation procedures and fixation in the presence of ruthenium red caused condensation of the ECM, especially in the cumulus layer, and thus produced a significant decrease in the diameter of the OCC.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 81
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 339-349 
    ISSN: 0148-7280
    Keywords: Xenopus ; oocytes ; meiosis ; progesterone ; MPF ; monensin ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The carboxylic ionophore monensin inhibits the meiotic maturation of the Xenopus oocyte. When oocytes are exposed to high concentrations of monensin (10 μM), both progesterone and MPF-induced (maturation-promoting factor-induced) maturations are blocked. Lower doses of monensin (1-10 μM) do not inhibit the formation or amplification of MPF activity in the oocyte cytoplasm; however, breakdown of the nuclear envelope does not occur. These observations show that monensin, which is known to abolish intracellular proton gradients, interferes with the mechanism of the breakdown of the nuclear envelope induced by MPF.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 82
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 45-56 
    ISSN: 0148-7280
    Keywords: blastocyst ; messenger RNA ; heat shock ; recombinant DNA ; actin ; transcription ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: We have utilized the rabbit 6-day blastocyst as a model system in which to examine the effect of environmental stress on embryonic gene expression. Elevation of the incubation temperature from 37 to 43 °C, exposure to 50 μM sodium arsenite or mechanical injury (resulting in the structural collapse of the 6-day rabbit blastocyst) was found to depress total protein synthesis as well as enhance the synthesis of a 70,000-dalton stress-induced protein. The molecular mass of this stress protein is similar to a heat shock protein (HSP) found in other eukaryotic systems. A recombinant DNA probe consisting of the 5′ end of a mouse gene for a 70,000-dalton HSP hybridized to RNA isolated from heat shocked, sodium arsenite-treated, and mechanically injured blastocysts but not to RNA isolated from control embryos. These results as well as in vitro translation data suggest that the expression of the 70 K HSP is controlled at the transcriptional level. The levels of actin mRNA, as detected by means of a recombinant DNA probe encoding a Drosophila actin gene, did not undergo a major alteration following these different stresses. The relevance of these observations to embryonic cellular homeostatis is discussed.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 83
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 67-76 
    ISSN: 0148-7280
    Keywords: Pipistrellus kuhli ; spermatozoon ; uterine epithelium ; cell interactions ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In hibernating females of Pipistrellus kuhli, as well as in other bats previously described, the spermatozoa inseminated in autumn are stored in the uterus, both free and attached by their heads to the uterine epithelium, throughout winter.With the electron microscope the apical region of the attached sperm heads appears to be contained in plicae of the endometrial cells. Furthermore, a great number of microvilli protruding from the uterine epithelium participate in the interaction with spermatozoa. In the region of contact between the two cell types, their plasma membranes run parallel with a constant 12-nm gap. The sensitivity of these interactions to EDTA and hyaluronidase suggests an involvement of Ca++ and proteoglycans in these bindings, while their insensitivity to trypsin tends to exclude a role of proteins.In addition, evidence of exocytosis of dense granules just at the bottom of the plicae containing the spermatozoon suggests a transfer of material from the uterine epithelium to the intercellular space, thus supporting a physiological role of these interactions.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 84
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 93-95 
    ISSN: 0148-7280
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 85
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 119-125 
    ISSN: 0148-7280
    Keywords: mouse sperm ; abnormal sperm ; sperm transport ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Mice of the PL/J strain exhibit a high percentage of morphologically abnormal sperm and provide a model for studying the function of abnormal sperm. The ability of such sperm to reach the site of fertilization within the female reproductive tract has been investigated. We have found a decrease in the percentage of structurally abnormal sperm within the population that reaches the oviduct. This observation suggests either that there is an active selection against abnormal sperm or that they are physiologically disadvantaged in reaching the site of fertilization.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 86
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 97-105 
    ISSN: 0148-7280
    Keywords: ultrastructure ; fertilization ; sheep ; oocytes ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In vivo fertilization of sheep eggs has been studied by electron microscopy. Remnants of the acrosome reaction were present at the zona surface of every penetrated egg, indicating that the acrosome reaction in sheep occurs at the surface of the zona pellucida.To determine whether follicular oocytes could specifically bind spermatozoa, oocytes isolated from different size classes of antral follicles were transferred into the oviducts of mated ewes, recovered 4 hr 30 min later, and analyzed by electron microscopy. Oocytes from follicles up to 1 mm in diameter failed to bind spermatozoa and were not penetrated. In contrast, the zona of oocytes from follicles ≥ 2 mm in diameter induced the acrosome reaction. These oocytes were penetrated but failed to achieve cortical granule exocytosis and so to mount a block to polyspermy. Moreover, sperm nuclei incorporated into the ooplasm did not decondense although the sperm nuclear envelope was dispersed.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 87
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 143-152 
    ISSN: 0148-7280
    Keywords: antisperm antibody ; sperm antigen ; rat embryos ; in vitro culture ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Since we previously proved that the fertilized rat eggs in early developmental stage have antigen(s) cross-reacting to spermatozoa, the effect of antibody to spermatozoa on the cleavage of fertilized rat eggs was examined in vitro. Fertilized eggs from Fisher rats in the morula stage were cultured in vitro for 15 to 39 hr in the medium containing antibody to rat spermatozoa and rabit complement, and the developmental rates of morulae to blastocysts were compared with those cultured in the presence of either antibody or the complement alone. When rat morulae were cultured in the medium containing rabbit complement and IgG from rabbit antiserum to rat spermatozoa (heteroantibody) or from rat antiserum to rat spermatozoa (isoantibody), the development of moralae to blastocysts was markedly suppressed, whereas those cultured in the medum containing rabbit complement and IgG from the control rabbit serum or rabbit antibody IgG to rat spermatozoa alone without complement normally developed to the blastocysts. These results indicate that the antibody to spermatozoa in presence of complement can impair the in vitro development of fertilized rat eggs.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 88
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 361-372 
    ISSN: 0148-7280
    Keywords: Nucleolus ; sea urchin oogenesis ; germinal vesicle ; egg cytoplasm ; argyrophilic proteins ; NOR-silver staining ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: NOR-silver staining technique was applied to paraffin sections of sea urchin ovaries. The fibrillar component and the granular component of the nucleolus were stained dark brown and yellowish tan, respectively. Silver-stained particles were also observed in germinal vesicles (GV) during oocyte growth. After the breakdown of GV, such particles appeared both in female pronucleus and egg cytoplasm, suggesting dispersion of the stained materials from the GV to the egg cytoplasm in the course of the breakdown of GV. The silver-stained sites disappeared by the pretreatment with NaOH, trypsin, and pepsin but not with HCl, and RNase, indicating the protein derivation of silver-stained sites. These results indicate the stained materials are kinds of protein.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 89
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 127-142 
    ISSN: 0148-7280
    Keywords: Fertilization ; extracellular matrix ; cumulus ; hamster ; hyaluronic acid ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: To enhance preservation of the extracellular materials, we have fixed hamster and mouse oocyte cumulus complexes (OCC) for transmission electron microscopy in the presence of ruthenium red. Ruthenium red had four effects on the extracellular components of the freshly ovulated hamster OCC. It interacted with the surface of cumulus and corona radiata cells; it stabilized the extracellular matrix (ECM) that was comprised of granules and filaments; it produced moderate electron density and good structural definition in the zona pellucida, and it revealed occasional smalls granular depsits on the oolemma. The ECM observed between cells of the cumulus and corona radiata layers extended into the outer one third of the zona pellucida. The granule and filament matrix was removed from the cumulus layer, corona radiata, and pores of the zona pellucida by brief treatment with hyaluronidase. The extracellular components of oviducal OCC from hamsters and mice appeared similar to OCC removed from follicles of the hamster shortly before ovulation. However, oviducal OCC did show increased aggregation of granules in the ECM. In most cases where females had been mated and oocytes were fertilized, the extracellular components appeared similar to those seen in fresh OCC. Exceptions were noted in some oocytes that lacked cumulus and corona radiata cells. In these instances, the zona pellucida generally lacked the granule/filament matrix. After fertilization numerous small electrondense granules were noted in the perivitelline space. These were presumed to originate in the cortical granules and formed a new investing layer around the zygote. Our data suggest that the OCC becomes more difficult for a sperm to penetrate as it approaches the oocyte. The significance of these results is discussed with respect to sperm traffic in the OCC and the cortical reaction.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 90
    ISSN: 0148-7280
    Keywords: spermatozoal motility ; sperm separation ; BSA gradient ; bull ; rabbit ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The effect of equipment design, separatory media, and time and temperature of separation were studied. Discontinuous 4%/10% bovine serum albumin (BSA) gradients were used to isolate highly motile spermatozoa in rabbit and bull semen. For all conditions tested, motility of spermatozoa collected from the 4% BSA gradient layer (top) was less than or equal to the motility of the unseparated controls. Fractions collected from the 10% BSA gradient layer contained highly motile spermatozoa. In experiment 1, washed bull spermatozoa were diluted with phosphate-buffered saline (PBS) containing 2% BSA or 4% BSA before being fractionated on BSA columns contained in test tubes. Inclusion of BSA in PBS tended to reduce loss of motility during washing, but the proportion of sperm recovered was highest in PBS. In experiment 2, motility and recovery of buck spermatozoa collected from the 10% BSA gradient region tended to be higher when fractionation temperature was 30°C as compared to 35°C, and motility was significantly higher when incubation time was 30 min as compared to 1 hr. The proportion of sperm recovered was unaffected by incubation time. In experiments 1 and 2, 41 of 48 separations resulted in at least one fraction containing spermatozoa with motility greater than or equal to 90%. In the third experiment, the surface area on which bull and buck spermatozoa were layered was increased by forming the 4%/10% BSA gradients in conical supports. Separation of sperm on conically shaped columns was not as effective as on cylinders. The use of cylinders to support the BSA gradients and a separation time of 30 min at 30°C is recommended.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 91
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 187-232 
    ISSN: 0148-7280
    Keywords: spermatozoa ; zona-free egg ; egg ; fertilizing capacity ; sperm chromosome ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 92
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 241-251 
    ISSN: 0148-7280
    Keywords: ultrastructure ; fertilization ; cow ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: In vivo fertilization of cow eggs has been studied by electron microscopy. Eggs were recovered from intracervically inseminated heifers 30 to 42 hr after the onset of oestrus. The corona cells remained attached to 4 out of the 15 eggs studied, but no sign of sperm phagocytosis was noted.Spermatozoa close to the zona pellucida, but not in contact with it, were not acrosome reacted. In contrast, all sperm penetrating the zona pellucida had completed the acrosome reaction. Vesiculated products of the reaction were present at the zona surface of every penetrated egg, indicating that in this species, the acrosome reaction occurs at the surface of the zona pellucida.During sperm passage through the zona pellucida, the equatorial segment overlaid by its plasma membrane remained intact.Soon after penetration into the ooplasm, the sperm nucleus decondensed; at the same time, the female chromosomes resulting from the second meiotic division aggregated in a few masses of condensed chromatin. A nuclear envelope started to form around the condensed female chromatin, while it was not yet present around the decondensing male nucleus.After swelling, the two pronuclei presented similar ultrastructural morphology; they contained small, compact, agranular nucleoli with a large fibrillar center and unevenly distributed chromatin. The pronuclear envelope contained pores and presented characteristic blebbing. The endoplasmic reticulum was closely apposed to the nuclear envelope and large Golgi structures were proximal to the pronuclei.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 93
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 283-299 
    ISSN: 0148-7280
    Keywords: Mouse ; spermatozoa ; cyclic nucleotides ; adenylate cyclase ; phosphodiesterase ; capacitation ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The role of cyclic nucleotides in sperm capacitation is equivocal. Using conditions known to support mouse sperm capacitation after 120 min incubation in vitro, the cAMP and cGMP contents of epididymal spermatozoa were measured and the cGMP/cAMP ratio determined. The initial high cAMP content detected upon release of spermatozoa decreased within 30 min to a lower plateau, which was then maintained throughout incubation. With the cGMP content remaining approximately constant, the cGMP/cAMP ratio increased over 120 min. In the presence of 2 mM caffeine, an increased cAMP content was noted at 0 and 30 min before a fall to the plateau level. To investigate cyclic nucleotide metabolism, adenylate cyclase and phosphodiesterase activities were compared in two sperm populations, one essentially uncapacitated and the other incubated for 120 min. Adenylate cyclase activity, higher in the presence of 2 mM Mn2+ compared to Mg2+, showed increased activity at 120 min compared to 30 min incubation, while phosphodiesterase activity decreased during this period. The ability of spermatozoa to form adenosine and inosine from cAMP indicated endogenous 5′-nucleotidase and deaminase, as well as phosphodiesterase, activities. Although the endogenous cAMP content appeared to remain constant during the time that acrosome loss, hyperactivated motility and fertilizing ability can be demonstrated, activities of the enzymes responsible for cAMP metabolism indicate an increased potential for cAMP availability and turnover. The increased cGMP/cAMP ratio may also play a role during capacitation.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 94
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 301-318 
    ISSN: 0148-7280
    Keywords: cytochemistry ; zona pellucida ; ovarian follicles ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The reactivity of the glycoproteins of ovarian follicles of the dog, rabbit, and mouse were compared, using the Alcian blue (pH 0.5) and Alcian yellow (pH 2.5) technique at the light-microscope level and the periodic acid-chromic acid-silver methenamine technique at the electron-microscope level.In paraffin sections, the rabbit and mouse show the appearance of both zona pellucida and follicular fluid in the earliest growing follicles. In the dog, there is a sequence of development with the follicular fluid appearing late, after much of the zona has been secreted. The zona and follicular fluid are highly sulfated in all animals. Zonae pellucidae of atresia appear to lose all traces of sulfation and become highly acidic. At the electronmicroscope level, oocytes contain little if any reactive glycoprotein material which can be related to zona pellucida formation. The initial appearance of the zona material occurs between follicle cell membranes extending outwards and away from the oocyte. Follicle cells of all species consistently contain a variety of reactive Golgi bodies and granules, with exocytotic vesicles, suggesting active synthesis and secretion of zona material.Our observations suggest that in the early stages of oogenesis, the follicular epithelium is responsible for at least part of the synthesis of the zona pellucida. It is possible therefore that both the oocyte and its follicle cells participate, probably on the sequential basis, in the synthesis of the mammalian zona pellucida.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 95
    ISSN: 0148-7280
    Keywords: rat ; superovulation ; superpregnancy ; preimplantation wastage ; zygote survival aminoglutethimide phosphate ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The purpose of this study was to test the hypothesis that the preimplantation losses of zygotes in pregnant superovulated juvenile rats was due to an imbalance of ovarian hormones. Twenty-seven or twenty-eight-day-old rats were injected with 20 iu of PMSG, 25 iu of hCG 50 hr later and mated overnight. From a mean ovulation rate of 52 ± 2 only 16 ± 4 zygotes survived after 4 days. After ligation of the cervical ends of the uteri on the day following fertilization the mean yield of zygotes was 22 ± 6. Ovariectomy on the day of fertilization increased the yield of zygotes to 39 ± 6, but the recovery of the zygotes was seriously complicated by postoperative adhesions and deformations of the adnexa. Inhibition of steroidogenesis with aminogluthehimide phosphate also increased the yield of zygotes. The optimal dose was 45 mg in six divided doses over 3 days, which gave a mean recovery of 57 ± 3 zygotes (of which 75% were blastocysts), that is 100% salvage. A lower dose (30 mg) reduced the recovery to the level of untreated animals, while increasing it to 60 mg resulted in maternal mortality and morbidity, as well as in developmental retardation of zygotes.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 96
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. i 
    ISSN: 0148-7280
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 97
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 253-265 
    ISSN: 0148-7280
    Keywords: sperm motility ; hyperactivation ; acrosome reaction ; spermatozoa ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: High-speed videomicrography was used to compare the movement characteristics of hamster epididymal sperm which completed the acrosome reaction in vitro with those of unreacted sperm in the same sample. More than 90% of the motile sperm incubated for 4.25 hr in a modified Tyrode's medium containing bovine serum albumin, taurine, and epinephrine were hyperactivated and about half were acrosome reacted. The flagella of reacted sperm beat with significantly lower frequency and bent into more acute curves than those of unreacted sperm. Lowered beat frequencies were not attributable to aging, because sperm induced to react synchronously at 3.5 hr using lysophosphatidyl choline beat with similar lowered frequencies. Both acrosome-reacted and unreacted hyperactivated sperm swam in circular trajectories resulting from asymmetrical flagellar beating. The flagellar beating of unreacted sperm was more symmetrical; consequently, they swam in larger circles and had the potential to cover space more rapidly. Some unreacted sperm, perhaps in transition towards hyperactivation, swam in helical trajectories.When preincubated sperm were added to slides containing oocytes in cumulus, some unreacted sperm initiated cumulus penetration. All reacted sperm failed to do so, adhering instead to the cumulus at its boundary. Reacted sperm attached to the zonae pellucidae of cumulus-free oocytes via the region of the inner acrosomal membrane. Unreacted sperm attached via the equatorial region, but pivoted about the point of attachment, thus failing to generate sustained thrust against the zona. In conclusion, unreacted hyperactivated sperm have a different potential than reacted sperm for movement and interaction with egg vestments.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 98
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 267-281 
    ISSN: 0148-7280
    Keywords: sea urchin sperm ; catalase ; peroxidase ; phenylhydrazine ; 3-amino-1,2,4-triazole ; azide ; fertilization ; polyspermy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: The release of hydrogen peroxide (H2O2) by the fertilized sea urchin egg has been shown to assist in the prevention of polyspermy [Coburn et al, 1981; Boldt et al, 1981]. Physiological data suggested that egg-derived H2O2 reacts with a phenylhydrazine-sensitive sperm peroxidase to inactivate sperm, while a 3-amino-1,2,4-triazole-sensitive catalase acts to protect sperm from H2O2 [Boldt et al, 1981]. Strongylocentrotus purpuratus sperm contain heat and pronase labile catalase and peroxidase activities. Differential extraction of sperm (hypotonic phosphate buffer for catalase and Triton X-100 at high ionic strength for peroxidase) results in complete separation of these enzyme activities. The catalase is highly sensitive to inhibition by azide and 3-amino-1,2,4-triazole, and less sensitive to inhibition by phenylhydrazine. The peroxidase is highly sensitive to inhibition by phenylhydrazine and relatively insensitive to 3-amino-1,2,4-triazole and azide. These results show that two distinct H2O2 reactive enzymes, catalase and peroxidase, are present in sea urchin sperm, and are consistent with our hypothesis concerning the biological functions of these enzymes in fertilization.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 99
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984) 
    ISSN: 0148-7280
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 100
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 10 (1984), S. 415-422 
    ISSN: 0148-7280
    Keywords: mouse ; fertility ; fertilization ; sperm ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: This study was conducted to determine the optimal concentration of sperm to use for the insemination of females to detect differences among strains of mice in the percentage of eggs fertilized. Female ICR mice were inseminated with sperm of concentrations ranging from 0.25 to 8 × 106/50 μl from males of either DBA/2N, CF1, or C57BL/6N strains. Differences among strains were detected only when approximately 50% of the eggs were fertilized but not when each of the strains fertilized either a high or low percentage of eggs. The optimal concentration of sperm therefore was the concentration that gave approximately 50% fertilized eggs.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...