Relation between interastral distance, time of furrow initiation, and rate of furrow progress in cylindrical sand dollar eggs

✍ Scribed by Rappaport, R. ;Rappaport, Barbara N.

• Publisher: John Wiley and Sons
• Year: 1987
• Tongue: English
• Weight: 539 KB
• Volume: 243
• Category: Article
• ISSN: 0022-104X
• DOI: 10.1002/jez.1402430308

✦ Synopsis

The purpose of this investigation was to determine whether measurable characteristics of furrow activity were affected when the distance between the asters was manipulated. The mitotic apparatus of cleaving Echinarachnius parma eggs was broken by passing the egg several times through a constricting pipet nozzle. Manipulated eggs were then confined in 80 pm i.d. silicone rubber capillaries. When the astral pairs developed before second cleavage, the distances between the pairs often differed. When the difference between interastral distances was 8.6 pm or less, furrows developed in the normal relation to both astral pairs within 1 minute in 31 of 35 cases. When the difference of interastral distances was greater than 8.6 pm, the furrow appeared first in association with the smaller distance in 53 of 54 cases. In all (24) cases in which the rates of progress of each astral pair were measured, the furrow formed between the closer astral pair progressed more rapidly when the distance was greater than 8.6 pm. No significant correlation between the rates of furrow progress and the magnitude of interastral distances measured 4 minutes before the beginning of furrowing could be demonstrated.