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  • 1
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    Chromosome segregation in crane-fly spermatocytes: cold treatment and cold recovery induce anaphase lag (1982)
    Springer
    Details
    Publication Date: 1982-08-01
    Print ISSN: 0009-5915
    Electronic ISSN: 1432-0886
    Topics: Biology , Medicine
    Published by Springer
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  • 2
    Electronic Resource
    Electronic Resource
    Chromosome segregation in crane-fly spermatocytes: cold treatment and cold recovery induce anaphase lag (1982)
    Springer
    Chromosoma 85 (1982), S. 619-631 
    Details
    ISSN: 1432-0886
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Anaphase lagging of autosomes was observed in 6.1±5.4% of the primary spermatocytes in untreated larvae of the crane fly, Nephrotoma suturalis. Lagging was induced by exposure of larvae to 6 ° C and during recovery at 22 ° C from exposure to 0.2, 2, and 6 ° C. The incidence of anaphase lag was maximal at 80 to 90 min of recovery. Induced lagging was observed at that recovery time after exposures of only 2.5 h to 2 or 0.2 ° C, but its incidence increased with longer exposures. As many as 85% of the cells in anaphase contained autosomal laggards after 61 h at 2 ° C and 80 to 90 min of recovery. At 2 ° C, cells reached the prophase-prometaphase transition, but spindles did not appear to form. Those cells proceeded through prometaphase during recovery, reaching mid-anaphase after 80 to 90 min of recovery. Chromosomes that lagged at anaphase during recovery from 2 ° C were observed in living cells to be half-bivalents derived from bivalents that congressed to the metaphase plate. One or both half-bivalents of any bivalent could lag. In some cells, one half-spindle had more half-bivalents than the other. Cells with autosomal laggards often did not cleave, and in uncleaved cells the second division employed spindles having two, three, or four poles. The basis of induced lagging might be a lapse in spindle attachment or motive force application at the start of anaphase or a failure of chromosomes to achieve proper orientation before the onset of anaphase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00330776
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  • 3
    Electronic Resource
    Electronic Resource
    An analysis of spindle ultrastructure during anaphase of micronuclear division in Tetrahymena (1980)
    New York, NY : Wiley-Blackwell
    Cell Motility and the Cytoskeleton 1 (1980), S. 41-61 
    Details
    ISSN: 0886-1544
    Keywords: mitosis ; mitotic spindle ; kinetochore ; microtubule ; micronucleus ; Tetrahymena ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Mitotic micronuclei were isolated from Tetrahymena thermophila and data on spindle ultrastructure were obtained from serial, transverse sections. Comparison of data from nuclei at meta- and early anaphase with data from nuclei at late anaphase showed that during anaphase, sister kinetochores move from the equator to the spindle poles, but kinetochore translocation occurs without any apparent change in either the number or length of kinetochore microtubules. This unprecedented result is ascribed significance with regard to the mechanism of kinetochore transport since there are only a limited number of ways that result could be achieved. The organization of the peripheral sheath changes during anaphase as evidenced by gaps in the sheath at late anaphase. Numerous kinetochore and non-kinetochore microtubules are located in polar regions of the spindle at late anaphase, whereas those regions contained only peripherally arranged microtubules at earlier stages. Tracking of individual kinetochore microtubules in late anaphase nuclei showed that some of them appeared to become incorporated into the peripheral sheath near the pole. At early and late anaphase, crossbridges connect adjacent microtubules throughout the spindle poleward to the kinetochores, as well as in the interzone.
    Additional Material: 14 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cm.970010105
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  • 4
    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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  • 5
    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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