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  • 1
    Electronic Resource
    Electronic Resource
    Movement of Myzostomum spermatozoa: Calcium ion regulation of swimming direction (1994)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 28 (1994), S. 135-142 
    Details
    ISSN: 0886-1544
    Keywords: bidirectional swimming ; flagellar movement ; helical bends ; 9+0 axoneme ; planar bends ; viscosity ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Spermatozoa of the small myzostomid worm Myzostomum cirriferum usually swim with the flagellum foremost but occasionally stop and then swim with the head foremost. The spermatozoa have axoneme of the 9+0 type; thus each lacks the central pair microtubules. The flagellum emerges in the anterior end of the cell body and attaches to it with junctions. To understand the mechanism regulating the swimming direction of the spermatozoa, we recorded the sperm and their flagellar movements using a video camera with a high-speed shutter. The effects of calcium and viscosity on these movements were also examined.The cell body with the flagellum attached to it formed a curved plate during beating, while the free portion of the flagellum beats with small helical bends. Motive force to propel a spermatozoon was mainly due to the bends in the cell body. The spermatozoa reversed the direction of their swimming as a result of a change in the direction of bend propagation. The direction of bend propagation was regulated by calcium; the bends in the cell body propagated from the end of the head toward the free portion of the flagellum at low concentrations of Ca2+, whereas the direction of bend propagation was reversed at high concentrations of this ion. High viscosity of the medium stimulated a change in the direction of bend propagation. © 1994 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970280205
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  • 2
    Electronic Resource
    Electronic Resource
    Comparative study of the beat patterns of american and asian horseshoe crab sperm: Evidence for a role of the central pair complex in forming planar waveforms in flagella (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 9 (1988), S. 264-270 
    Details
    ISSN: 0886-1544
    Keywords: axoneme ; flagellar movement ; helical wave ; planar wave ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: American horseshoe crab sperm flagella have the typical 9+2 structure whereas Asian horseshoe crab sperm flagella have a 9+0 axoneme lacking central pair and central sheaths. Beat patterns of the American and the Asian horseshoe crab sperm were recorded by means of a high-speed video system (200 fields/second) and were compared in order to study the role of the central pair of the axoneme in ciliary and flagellar movement.The American horseshoe crab sperm beat with relatively planar waves, whereas the Asian horseshoe crab sperm beat with right-handed helical waves. These results suggest that the central complex plays an important role in forming planar waves, whereas it is not essential for the conversion of microtubule sliding into axonemal bends.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970090308
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  • 3
    Electronic Resource
    Electronic Resource
    Mechanical properties of sperm flagella (1982)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982), S. 149-152 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970020728
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  • 4
    Electronic Resource
    Electronic Resource
    Flagellar movement of intact and demembranated, reactivated ram spermatozoa (1987)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 8 (1987), S. 375-391 
    Details
    ISSN: 0886-1544
    Keywords: axoneme ; cilia ; flagella ; reactivation ; ram sperm ; high speed video microscopy ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The flagellar movement of intact ejaculated ram sperm, and of demembranated models reactivated with ATP, has been studied using high-speed, high-resolution video microscopy.Intact sperm attached to the coverslip by their heads had an average beat frequency of 20.9 Hz and an average wave amplitude of 20.2 μm. There was little difference in the beat frequency or waveform of these sperm and sperm swimming freely near the coverslip or captured by their heads with a micropipette and held far from the coverslip, inducationg that the flagellar waveform of ram sperm is relatively resistant to distorition as a result of immobilization of the head or proximity to a surface. The beat envelope was nearly planar as determined by observations of free-swimming sperm and sperm captured by their head and oriented so they were beating either parallel or perpendicular to the plane of focus.The effect of various conditions for demembranation and reactivation of the sperm were examined. Treatment of sperm with 0.2 % Triton X-100 removed most of their plasma membrane. Under optimal conditions, nearly 100 % of the demembranted sperm reactivated at MgATP2- concentrations ranging from ∼4 μM to ∼20 mM. From ∼ 1 mM to ∼ 10 mM MgATP2-, their beat pattern closely resembled that of intact sperm; beat frequency depended on MgATP2- concentration. Percent motility was maximal between pH 7.5 and 8.0 and decreased sharply below pH 7.0 and avove pH 8.5. The addition of 50 μM cAMP to the reactivation medium had no effect on percent motility or the beat pattern and did not accelerate the initiation of movement.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970080410
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  • 5
    Electronic Resource
    Electronic Resource
    Flagellar movement of human spermatozoa (1986)
    New York, NY : Wiley-Blackwell
    Gamete Research 13 (1986), S. 185-197 
    Details
    ISSN: 0148-7280
    Keywords: flagellar movement ; human spermatozoa ; viscosity ; cervical mucus ; hyaluronic acid ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Flagellar movement of human spermatozoa held by their heads with a micropipette was recorded by means of a video-strobe system. Spermatozoa were studied in normal Hanks' solution, Hanks' solution with increased viscosity, cervical mucus, and hyaluronic acid.When flagellar movement in normal Hanks' solution was observed from the direction parallel to the beating plane, segments of the flagellum in focus did not lie on a straight line but on two diverging dashed lines. The distance between the two dashed lines was about 20% of the bend amplitude in the major beating plane. These observations indicate that flagellar beating of human spermatozoa in normal Hanks' solution is not planar. In contrast, segments of the flagellum in focus lay on a straight line when the spermatozoa were observed in Hanks' solution with increased viscosity, cervical mucus, or hyaluronic acid. In normal Hanks' solution, free swimming spermatozoa rotated constantly around their longitudinal axes with a frequency similar to the beat frequency, whereas little or no rotation of spermatozoa occurred in Hanks' solution with increased viscosity, in cervical mucus, or in hyaluronic acid.We conclude that human spermatozoa in normal Hanks' solution beat with a conical helical waveform having an elliptical cross section, the semiaxes of which have a ratio of 0.2. The three-dimensional geometry of the flagellar movement is responsible for the rotation of the sperm around their longitudinal axes.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120130302
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