A CORRELATIVE STUDY OF EXPERIMENTALLY CHANGED 1ST CLEAVAGE AND JANUS DEVELOPMENT IN THE TRUNK OF PLATYNEREIS-DUMERILII (ANNELIDA, POLYCHAETA)
A CORRELATIVE STUDY OF EXPERIMENTALLY CHANGED 1ST CLEAVAGE AND JANUS DEVELOPMENT IN THE TRUNK OF PLATYNEREIS-DUMERILII (ANNELIDA, POLYCHAETA)
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DOI：
10.1007/bf00376021
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发表时间：
1987-01-01
期刊：
影响因子：
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通讯作者：
FISCHER, A
中科院分区：
文献类型：
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作者：
DORRESTEIJN, AWC;BORNEWASSER, H;FISCHER, A
在第一次卵裂前用细胞松弛素B(CCB)处理的受精卵中，观察到了各种各样的发育效应。其中一个影响是第一次卵裂的延迟。经过处理的胚胎可能会跳过第一个甚至多个卵裂周期，成为多核胚胎。一旦这些卵子开始分裂，它们的卵裂面就会与同步受精的对照组处于相同的位置。因此，跳过第一个正常卵裂周期的胚胎的第一次卵裂是子午线的且相等的，但它们的第二次卵裂与对照组的第三次卵裂一样是赤道的。没有观察到跳过早期卵裂的胚胎显示出正常的器官发生，但发育成囊状胚胎，细胞分化很少。CCB处理的另一个效果是改变那些与对照组同步开始分裂的胚胎中的卵裂球大小。虽然大多数处理过的胚胎遵循正常的卵裂模式，即它们在正确的时间和不平等的情况下进行卵裂，但其中一些胚胎的卵裂是相等的或几乎相同的(充分)。这些胚胎大多在随后的卵裂周期中出现卵裂缺陷，成为异常的水泡状胚胎。然而，这些胚胎中的一些按计划分裂并同样或充分发育成幼虫，表现出完全复制的粪便和隔膜排卵(占所有处理卵子的0.3%)，被描述为双卵形。这意味着双重分裂的发生和几何上改变的第一次分裂模式是相关的现象。文中还讨论了这种重复现象的性质、来源及其对腹背极的影响。
Among zygotes ofPlatynereis dumeriliitreated with cytochalasin B (CCB) prior to first cleavage, a wide variety of developmental effects were observed. One effect is a delay in the first cleavage. Treated embryos may skip the first or even more than one cleavage cycle and become multinucleated. Once these eggs start cleaving their cleavage plane takes the same position as in synchronously fertilized controls. Accordingly, the first cleavage in embryos having skipped the first normal cleavage cycle is meridional and equal, but their second cleavage is equatorial as in the third cleavage in controls. None of the embryos that were observed to skip early cleavages showed normal organogenesis, but developed into vesicle-shaped embryos with little cytological differentiation. Another effect of CCB treatment is altered blastomere size in those embryos which begin cleaving in synchrony with controls. While the majority of treated embryos followed a normal cleavage pattern, i.e. they cleaved at the right time and inequally, some of them cleaved equally or almost equally (adequally). Most of these embryos showed cleavage defects in subsequent cleavage cycles and became abnormal vesicle-shaped embryos. However, some of these embryos cleaving on schedule and equally or adequally developed into juvenile worms showing complete duplication of urites and parapodial rows (0.3% of all treated eggs) and are described as Janusduplicitates. This means that the occurrence ofduplicitatesand geometrically altered first cleavage patterns are correlated phenomena. The character and origin of the duplications and the consequences for dorsoventral polarity are discussed.