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  • 1
    Electronic Resource
    Electronic Resource
    A study of bend formation in locally reactivated hamster sperm flagella (1983)
    Springer
    Journal of muscle research and cell motility 4 (1983), S. 625-645 
    Details
    ISSN: 1573-2657
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Mature golden hamster sperm were demembranated with Triton X-100, and the flagellum was reactivated locally by iontophoretic application of ATP at various distances from the base. The response was a brief local straightening of a short length of the flagellum followed by the formation of a pair of bends beyond the two ends of the straight region. The two possible proximo-distal sequences of bends, either PR (principal and reverse bends) or RP, could be distinguished and their incidence studied. The formation of PR and RP bend pairs is interpreted as the result of active sliding of the axonemal doublet subsets 1–4 and 6–9 respectively. The probability of obtaining a PR response increased (1) with the initial local curvature of the resting R bend and (2) with the distance of the stimulated site from the flagellar base; it decreased with the duration of incubation after demembranation. The patterns of response in the middle and the principal piece of the flagellum were basically similar although the former was weaker and more complicated. Quantitative analysis of the ATP-induced movements indicates little or no net microtubule displacement distal to the pair of induced bends, suggesting the cancelling of microtubule displacements in the two bends. However, the expected balance in the rate of growth of the two bends was upset by the decay of one bend simultaneously with decay of the original adjacent bend. Propagation of the interbend region started before the growth of the pair of bends reached its maximum, and seemed to be triggered by a critical bend curvature. Propagation was always in the direction base to tip. Experimental findings also suggest a role in the determination of the waveform for the fibrous structures on the periphery of the axoneme which are characteristic of the mammalian sperm flagellum. The present study strengthens the experimental evidence for the mathematical model which proposes that active sliding occurs mainly in the interbend region and causes bending of segments in opposite directions. In addition our findings indicate that the activation of alternate halves of the axoneme is curvature dependent, suggesting a basis for the flagellar oscillation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00712157
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  • 2
    Electronic Resource
    Electronic Resource
    Ultrastructure of the perfused rat epididymis: Effect of luminal sodium ion concentration (1982)
    Springer
    Cell & tissue research 226 (1982), S. 407-425 
    Details
    ISSN: 1432-0878
    Keywords: Luminal perfusion ; Rat epididymis ; Epithelial structure ; Absorption ; Water transport
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The appearance of the rat epididymal epithelium changed when it was perfused in vivo through the lumen with unphysiologically high sodium ion concentrations; dilatation of intercellular spaces (ICS) at threshold concentrations of 30mM-Na+ in the cauda and about 55mM-Na+ in the corpus was associated with absorption of water from the lumen. Despite the distended ICS, junctional complexes appeared intact, and their integrity was confirmed by the exclusion of luminal horseradish peroxidase (HRP) from the ICS, and by demonstrating that circulating [3H]inulin did not enter the lumen. Smooth ER and lipid droplets in the principal cells of the corpus epididymidis were well maintained, and the preservation of granular ER in principal cells of the cauda epididymidis lent morphological support to the continued secretion of protein in this segment. However, occasional distension or involution of inner Golgi cisternae was evident in principal cells after 3–6 h perfusion. In contrast to multivesicular bodies of principal cells, the apical and basal vacuoles characteristic of clear cells changed in size with different perfusing solutions. When low Na+ concentrations were perfused large translucent vacuoles were frequently found in the apical cytoplasm of clear cells in the corpus and cauda epididymidis, and filled vacuoles became larger and showed a decrease in content density in the cauda epididymidis. These large vacuoles were absent from tissue perfused with high Na+ concentrations. Normal pinocytotic activity of both cell types was demonstrated by perfusing HRP which was taken up by the normal route in principal cells, with some transfer to the Golgi cisternae. By far the most HRP was accumulated in clear cell vacuoles irrespective of the composition of the perfusing solution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218369
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  • 3
    Electronic Resource
    Electronic Resource
    Effects of cyclic AMP on the motility of mature and immature hamster epididymal spermatozoa studied by reactivation of the demembranated cells (1984)
    New York, NY : Wiley-Blackwell
    Gamete Research 9 (1984), S. 99-114 
    Details
    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
    URL: http://dx.doi.org/10.1002/mrd.1120090109
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