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  • 1
    Electronic Resource
    Electronic Resource
    Chromosome movement during meiotic prophase in crane-fly spermatocytes. I. Observations on living cells and the effects of cyanide and cold treatment (1982)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 2 (1982), S. 183-195 
    Details
    ISSN: 0886-1544
    Keywords: crane flies ; meiosis ; spermatocytes ; chromosome movement ; nuclear envelope ; prophase ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Meiotic prophase in spermatocytes of the crane fly, Nephrotoma suturalis, involves both the condensation and the movement of bivalent chromosomes. Since crane flies have only four bivalents that appear highly condensed during late prophase, changes of position and orientation of those bivalents relative to one another can be seen easily in living cells. Chromosome movement during the final 1 to 2 hr of diakinesis was analyzed in detail. Maximal velocities of prophase movements were between 0.1 and 1 μM/min. Metakinetic movements during prometaphase have similar velocities. To assess the physiological basis of prophase movements, experiments employing cyanide and cold treatment were performed. Prophase movements were abolished completely by cyanide, and, for the most part, the velocities of chromosomes in the cold at 2°C and 6°C were less than that of untreated cells at 22°C. The results suggest that prophase movements are energy dependent and may involve an enzyme-catalyzed process occurring in close association with the nuclear envelope.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970020209
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  • 2
    Electronic Resource
    Electronic Resource
    Chromosome movement during meiotic prophase in crane-fly spermatocytes: III. Microtubules and the effects of Colcemid, nocodazole, and vinblastine (1985)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 5 (1985), S. 393-413 
    Details
    ISSN: 0886-1544
    Keywords: chromosome movement ; Colcemid ; nocodazole ; meiotic prophase ; microtubules ; vinblastine ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effects of Colcemid, nocodazole, and vinblastine on microtubules and on the movement of chromosomes during late diakinesis were investigated in spermatocytes of the crane fly Nephrotoma suturalis. The kinds of movements observed in untreated cells - sex bivalent rotations, sex bivalent excursions, and rotations and positional changes of autosomal bivalents - also were observed in drug-treated cells. These results were obtained in living cells in which the disruption and inhibition of microtubule assembly had been confirmed with polarized light microscopy. Effects of Colcemid and nocodazole also were assessed in fixed cells using electron microscopy. The results are in agreement with a hypothesis that microtubules are not a force-generating component of the molecular machinery that brings about prophase movements.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970050504
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  • 3
    Electronic Resource
    Electronic Resource
    Chromosome movement during meiotic prophase in crane-fly spermatocytes. II. Analysis of polarization of chromosomes and their association with the nuclear envelope (1983)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 3 (1983), S. 261-271 
    Details
    ISSN: 0886-1544
    Keywords: chromosome movement ; meiosis ; spermatocytes ; prophase ; nuclear envelope ; aster ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Association of bivalent chromosomes with the astral centers and nuclear envelope was analyzed in crane-fly spermatocytes during the final hours of diakinesis. In contrast to other systems in which movement of chromosomes during diakinesis correlates with the clustering of bivalents near the astral centers, such clustering is not prevalent in crane-fly spermatocytes. Polarization indices of bivalents calculated 5 to 10 minutes before the end of diakinesis provided evidence for polarization of only a fraction of all bivalents. Similar results were obtained in a large number of fixed cells in which asters and chromosomes were preferentially stained. Ultrastructural analysis of cells in late diakinesis revealed significant contact between bivalents and the nuclear envelope in all 46 cells that were analyzed. The extent of contact in some cells was greater than in others. Sites of contact included the telomeric ends of bivalents, and in some cases the distribution of contact sites suggested the possible involvement of centromeres in chromosome-nuclear envelope association. The results are consistent with the hypothesis that a dynamic interaction between chromosomes and nuclear envelope may exist during late prophase, when the movement of chromosomes is known to occur.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970030306
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