Changes in Lipid Droplet Localization During Embryogenesis of the Silkworm, Bombyx mori
Changes in Lipid Droplet Localization During Embryogenesis of the Silkworm, Bombyx mori
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DOI：
10.2108/zsj.25.580
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发表时间：
2008-06
期刊：
影响因子：
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通讯作者：
Y. Yamahama;K. Seno;T. Hariyama
中科院分区：
文献类型：
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作者：
Y. Yamahama;K. Seno;T. Hariyama
脂滴被认为是鳞翅目卵在胚胎发生后期最重要的能量来源之一，但其融入胚胎的过程尚不清楚。本文采用形态学和生物化学方法研究了家蚕胚外卵黄脂滴向胚内转移的过程。形态学研究表明，胚外卵黄脂滴在胚胎发育过程中以三种不同的方式在三个点上进入胚胎。一些脂滴在胚分裂前直接从胚外卵黄转移到胚内。然而，大部分脂滴和胚外蛋黄的其他成分都是通过背部闭合时的形态发生包涵和发育中的毛虫在孵化前摄入胚外蛋黄而融入胚胎的。生化研究也得到了类似的结果。因此，我们认为脂滴从胚胎外卵黄进入胚胎有三个步骤。此外，卵子中脂滴总量的形态学和生化数据表明，脂滴主要在胚胎发生后期消耗，似乎与气管发育同步。
Abstract Lipid droplets are considered one of the most important energy sources in lepidopteran eggs during late embryogenesis, but the process of their incorporation into the embryo is as yet unknown. The present study focused on the process of transition of lipid droplets from the extraembryonic yolk to the embryo of the silkworm Bombyx mori, using morphological and biochemical approaches. The morphological study revealed that the incorporation of lipid droplets from the extraembryonic yolk into the embryo occurs at three points and in three different ways during the development of the embryo. Some lipid droplets were translocated directly from the extraembryonic yolk to the embryo before the blastokinesis stage. However, the majority of lipid droplets together with the other components of the extraembryonic yolk were incorporated in the embryo via both morphogenetic inclusion during dorsal closure and ingestion of the extraembyonic yolk by the developing caterpillar prior to hatching. Similar results were obtained from the biochemical study. Thus, we propose that there are three steps in the incorporation of lipid droplets from the extraembryonic yolk into the embryo. In addition, morphological and biochemical data concerning the total amount of lipid droplets in the egg suggested that lipid droplets were mainly consumed during late embryogenesis, seeming to synchronize with tracheal development.