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  • 1
    Electronic Resource
    Electronic Resource
    A Ubiquitous Protease Regulates the Motility of Spermatozoa (1987)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 513 (1987), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1987.tb25116.x
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  • 2
    Electronic Resource
    Electronic Resource
    Is a Transglutaminase Involved in Sperm Motility? (1987)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 513 (1987), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1987.tb25117.x
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  • 3
    Electronic Resource
    Electronic Resource
    cAMP/ATP relationship in the activation of trout sperm motility: Their interaction in membrane-deprived models and in live spermatozoa (1995)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 31 (1995), S. 159-176 
    Details
    ISSN: 0886-1544
    Keywords: trout ; spermatozoa ; ATP ; cAMP ; axoneme ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Live trout spermatozoa initiate flagellar motility for only a short period (30 sec at 18°C) during which their mean beat frequency decreases steadily from 60 to 20 Hz. Motility then stops abruptly. Investigations of the activation of movement in demembranated sperm points to cyclic-AMP being necessary for reactivation (half effect at 0.5μm) in some conditions. cAMP acts mainly by increasing the percentage of motile cells and not the beat frequency (BF) of the flagellar axoneme. Dibutyryl cAMP does not initiate movement or prolong motility of live sperm.The initiation of movement of demembranted trout sperm was investigated in various incubation conditions relative to previous phases of in vivo movement and to ATP concentration. In the absence of cAMP and in the presence of ATP lower than 25 μM, all sperm celi models were active with BF up to 15-20 Hz whatever their previous physiological condition. In contrast, at ATP concentrations above 100 μM, the fraction of active spermatozoa decreased proportionally but the BF of the active ones increased so that, at 1 mM ATP up to 20 μM restored activity to 100% sperm models with a similar BF of 65 Hz.At ATP concentrations higher than 25 μM, cAMP was necessary in a concentration dependent manner in the reactivation, but not in the demembranation meduim. This dependence was found to be unrelated to a previous in vivo phase of movement. The antagonistic effects of ATP vs. cAMP were tested at various concentrations of both nucleotides: the apparent affinity for cAMP, measured as the concentration restoring movement of 50% cell models, was decreased from 15 nM at 0.1 mM ATP to 0.5 μM at 1 mM ATP; conversely, the affinity for ATP, measured as the concentration giving rise to the half maximal beat frequency, was not significautly affected when the concentration of cAMP was raised to 0.5 mM. Preincubation with phosphodiesterase (PDE) resulted in motility of 100% of sperm models even at low ATP concentration. This tends to show that cAMP must be constantly present to sustain motility.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970310208
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  • 4
    Electronic Resource
    Electronic Resource
    Protease inhibitor and substrates block motility and microtubule sliding of sea urchin and carp spermatozoa (1988)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 10 (1988), S. 518-527 
    Details
    ISSN: 0886-1544
    Keywords: 9 + 2 flagellar beating ; aprotinin ; axonemes ; protease inhibitor ; sperm motility ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effects of protease substrates and inhibitor, which have been previously shown to inhibit mammalian sperm motility (de Lamirande, E., and Gagnon, C. [1986] J. Cell Biol. 102:1378-1383), were investigated using reactivated sea urchin and carp spermatozoa as models of “9 + 2” flagella. Aprotinin in the 2 to 20 μM range interfered with sperm motility by reducing both the beat frequency and the percentage of motile spermatozoa. These inhibitory effects of aprotinin were reversible either by dilution or by the addition of high concentrations of MgATP to the incubation medium. Protease substrates with a lys-ester bond, such as N-α-benzyloxycarbonyl-lys thiobenzyl ester (BLT), also affected motility, but in the 0.1 to 0.5 mM range. As with aprotinin, both the flagellar beat frequency and the percentage of motile spermatozoa were partially and completely decreased, respectively. Analysis of the beat frequencies as a function of MgATP concentration in the presence and absence of 6 μM aprotinin indicated that this protease inhibitor affects sperm motility by decreasing the maximal flagellar beat frequency rather than by altering the axoneme's apparent Km for MgATP. Furthermore, aprotinin concentrations that blocked flagellar reactivation completely inhibited the sliding of microtubules from trypsinized axonemes. Basic proteins or polypeptides of pI close to that of aprotinin (10.3) were also potent inhibitors of the reactivation of motility. However, the characteristics of their inhibition of flagellar beat frequencies and reversibility of their effects suggested that they might be acting on sites different from those sensitive to aprotinin. The inhibitory effects of protease inhibitor and substrates, as well as results of experiments showing the absolute requirement of an intact ester bond for the inhibitory action of protease substrates, suggest that the involvement of a protease in the reactivation of 9 + 2 flagellar beating might be considered as a possible mechanism to explain aprotinin and BLT actions.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970100408
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  • 5
    Electronic Resource
    Electronic Resource
    Rise of internal Ca2+ accompanies the initiation of trout sperm motility (1989)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 14 (1989), S. 424-434 
    Details
    ISSN: 0886-1544
    Keywords: Quin-/ ; spermatozoa ; desmethoxyverapamil ; fluorescence ; K+ ; flagellar beating ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The initiation of motility of trout spermatozoa is inhibited by the presence of millimolar concentrations of external K+, but external Ca2+ might also be implicated in this control as it has been shown to antagonize the K+ inhibition of motility [S.M. Baynes et al.: J. Fish. Biol., 19:259-267, 1981]. The present work aimed to investigate internal Ca2+ levels during the motility phase of trout spermatozoa. Internal Ca2+ concentrations were monitored by the fluorescent quinoline Ca2+-indicator, “Quin-2” [R. Y. Tsien: Nature 290:527-529, 1981]. Trout spermatozoa were loaded with Quin-/ under conditions that gave efficient intracellular hydrolysis of Quin-2 and that did not impair the ability of loaded spermatozoa to initiate movement. The beat frequencies, cell velocities, and flagellar asymmetries of sperm movement were not significantly modified by the presence of the internal dye. Upon initiation of flagellar movement, an increase of the internal Quin-2 fluorescence was observed that reflected a sixfold increase of the free Ca2+ concentration. The free Ca2+ remained elevated after the cessation of movement. The variation of fluorescence was completed within 40 seconds, whereas the initiation of motility was nearly instantaneous, and the total duration of flageliar beating lasted for about 80-100 seconds (measurements at 11°C). The increase in the internal free Ca2+ concentration is completed after the initiation of flagellar beating but its occurrence correlates with that of sperm movement. Fluorescence increase was not observed in the presence of 40 mM K+, a condition in which spermatozoa did not initiate flagellar beating. In the presence of the Ca2+ channel blocker desmethoxyverapamil, neither sperm motility nor fluorescence increases were observed, which suggested that the increase of internal free Ca2+ was produced by a flux of external Ca2+ into the cell rather than by a mobilization of internal Ca2+ stores.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970140312
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  • 6
    Electronic Resource
    Electronic Resource
    Sperm chemotaxis in siphonophores: Identification and biochemical properties of the attractant (1986)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 6 (1986), S. 225-228 
    Details
    ISSN: 0886-1544
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970060222
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  • 7
    Electronic Resource
    Electronic Resource
    Synchronous triggering of trout sperm is followed by an invariable set sequence of movement parameters whatever the incubation medium (1991)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 20 (1991), S. 55-68 
    Details
    ISSN: 0886-1544
    Keywords: motility ; spermatozoa ; calcium ; potassium ; pH ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The movement of live trout spermatozoa is very brief (25 sec at 20°C) and conditions have been developed to get synchronous initiation of sperm motility which allowed quantification of the major parameters of sperm movement during the motility phase.Recorded flagellar beat frequencies decreased steadily from values of 55 Hz at the beginning to 20 Hz at the end of the motility phase. Sperm forward velocities followed a similar pattern from 250 to 20 μm.sec-1 in the same conditions and the diameters of sperm trajectories were reduced from 370 to 40 μm. Thus none of the characteristics of sperm movement was constant during the motile phase which ended abruptly by a straightening of the flagella.The decrease in flagellar beat frequencies and sperm velocities are much greater than what could be extrapolated from the decrease of intracellular ATP (Christen R. et al: Eur. J. Biochem, 166:667-671, 1987) or from measurements of ATP-dependence of reactivated sperm velocities (Okuno M. and Morisawa N.: In Biological Functions of Microtubules and Related Structures. New York: Academic Press, pp. 151-162, 1982). Therefore, the cessation of flagellar beating at 25 sec is not directly the result of the low concentration of intracellular ATP.The decrease in the diameters of sperm trajectories which occurred during the first part of the motility phase was correlated with [Ca]i measurements (Cosson M.P. et al, Cell Motil. Cytoskeleton, 14:424-434, 1989). The effect of Ca2+ at the axonemal level does not indicates that Ca2+ influx is previous to flagellar beating but rather suggests a classical Ca2+ regulation of the flagellar assymetry.The short duration of the motility phase and the characteristics of sperm movement were very similar in various conditions (high external K+, low pH media) where increased external Ca2+ or divalent ions were shown to overcome K+ and H+ inhibition of sperm motility, both conditions which have been shown to depolarize the plasma membrane potential (Gatti J.L. et al: J. Cell Physiol., 143:546-554, 1990).The present study of the parameters of sperm movement suggests that once motility is initiated, a defined set of axonemal events will take place whatever the external conditions.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970200107
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  • 8
    Electronic Resource
    Electronic Resource
    Xenopus spermatozoon: Correlation between shape and motility (1988)
    New York, NY : Wiley-Blackwell
    Gamete Research 20 (1988), S. 165-175 
    Details
    ISSN: 0148-7280
    Keywords: spermatozoon ; Xenopus ; Anuran ; flagella ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Xenopus spermatozoa have a characteristic corkscrew-shaped head and a flagellum with a conventional “9 + 2” structure (Bernardini et al.: J Ultrastruct Md Struct Res: 94:188-194). They are motile in water and media of low osmolarities, but not in media of osmolarities higher than 200 mosm/liter, regardless of the ionic composition. External calcium and pH are not involved in the inhibition of sperm movement at high osmolarities.The duration of sperm motion was less than 10 min, and both flagellar beat frequencies and sperm velocities declined progressively. However, in demembranated and reactivated tails, flagellar beating was sustained for longer times. Flagella propagated three-dimensional waves that induced a spinning motion of the whole spermatozoon. This pattern of movement is not dependent on the shape of the sperm head, since isolated, reactivated flagella exhibited three-dimensional waves.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrd.1120200207
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