ISSN:
1615-6102
Keywords:
Actin
;
Cytochalasin
;
Microtubules
;
Mitosis
;
Spindle
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary Mitosis in living cells ofOedogonium observed by time-lapse, was blocked by cytochalasin D (CD; 25–100 μg/ml). Normal prometaphase to anaphase takes 10–15 min; blockage of entry into anaphase by CD was reversible up to 2–2.5 h in CD and washout was followed within 10–20 min by normal anaphase and cytokinesis. After 3–6 h in CD, unseparated chromatids segregated randomly into two groups as the spindle slowly elongated considerably, becoming distorted and twisted. During this “pseudoanaphase”, chromatids sometimes split irregularly and this was stimulated by late washout of CD. CD affected chromosomal attachment to the spindle. If applied at prophase and prometaphase, spindle fibres entered the nucleus; chromosomes moved vigorously and irregularly. A few achieved metaphase only briefly. Treatment at metaphase caused chromosomes to irregularly release and after random movement, all slowly gathered at either pole. Upon removal of CD, chromosomes rapidly achieved metaphase and anaphase A and B soon followed. If CD took effect during anaphase, chromatids detaching from the spindle oscillated rapidly along it; anaphase and cytokinesis (phycoplast formation) were delayed as the cell attempted to correct for abnormal chromosomal behaviour. Thus, CD prevents normal kinetochore attachment to the spindle and actin may be the target for this response.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01273885
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