| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1987: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1986: ¥1,700,000 (Direct Cost: ¥1,700,000)
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| Research Abstract |
Following 1-methyladenine treatment, maturing oocytes of the starfish, Asterina pectinifera, were transferred to sea water containing 2.5% hexyleneglycol(HG). After about 20-30 min, meiotic apparatus(MA), clearly visible at first as a tiny point close to the cell membranes, began to increase in size with time. After having taken on increazing size, most of the larger MA became situated perpendicular or parallel to cell membranes, but near the cell center in the case of a few oocytes. The diameter of the aster of isolated MA at the metaphase of HG-treated oocytes was two or three times longer than that in the control experiment. Depending on its particular location in oocytes during maturation, the larger MA induced three diffrent events during meiotic division: giant polar body formation, unilateral furrowing in most oocytes, and equal cell division in a few oocytes. The frequency of these events depended on the time of transfer of oocytes to HG-SW during maturation.
Based on these findings, we attempted to present an explanation for the events induced by HG. When maturing oocytes were transferred to HG-SW, HG diffused gradually into them, stabilizing the migrating MA in its particular position during maturation, and causing its size to increase through reassembly of microtubules around it. The larger MA may cause the meiotic division of oocytes to change, leading to the subsequent inducement of the above three events, depending on the particular location in the oocytes during maturation.
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