These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Duration of division-related events in cleaving sand dollar eggs.
    Author: Rappaport R, Rappaport BN.
    Journal: Dev Biol; 1993 Jul; 158(1):265-73. PubMed ID: 8330673.
    Abstract:
    A minimal mechanism for cytokinesis comprises a stimulus-to-surface contraction, a receptive surface, and a localized surface contractile mechanism. Duration of each is brief and times when they function are predictable. The processes that begin and end the functional period of each component were investigated. Sand dollar blastomeres from the completion of first cleavage to the beginning of fourth cleavage were used. By changing a cell's shape, it was possible to determine whether its capacity to accomplish an activity is restricted to its usual time frame. The first appearance of the furrow was advanced about 5 min by confining the mitotic apparatus in a narrow cytoplasmic cylinder. The period when the mitotic apparatus induces furrowing was prolonged about 18 min by moving the mitotic apparatus in an elongate cell each time the furrow appeared. The period of active furrowing was prolonged to about 21.8 min by pushing the mitotic apparatus close to the cell margin and then stretching the region through which the unilateral furrow must pass. In relation to normal division cycle events, results showed that each event of cytokinesis can operate both before and after its normal active period. Components of the mechanism are capable of functioning for about half the period of the division cycle. Normal timing of events may be determined by geometrical factors and the normal consequences of each activity.
    [Abstract] [Full Text] [Related] [New Search]