The club-shaped gland of amphioxus: export of secretion to the pharynx in pre-metamorphic larvae and apoptosis during metamorphosis
The club-shaped gland of amphioxus: export of secretion to the pharynx in pre-metamorphic larvae and apoptosis during metamorphosis
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DOI：
10.1111/j.1463-6395.2008.00379.x
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发表时间：
2009-10-01
期刊：
影响因子：
1.2
通讯作者：
Koop, Demian
中科院分区：
文献类型：
--
作者：
Holland, Nicholas D.;Paris, Mathilde;Koop, Demian
在文昌鱼幼体中，棒状腺体是连接咽腔与外部环境的管道。腺的功能和它的命运在幼虫到幼体的变态一直是有争议的。在这里，我们使用固定剂，包括钌红保存细胞外分泌物（推测糖蛋白）在后期前变质幼虫。此过程显示，在棒状腺体的管腔内和咽部邻近腺体内口处可见淡红色纤维颗粒状物质。这一发现加强了这样一种观点，即棒状腺体的分泌物被输出到咽腔，以帮助形成一个粘液陷阱，用于捕获进入口腔的食物颗粒。我们还使用末端脱氧核苷酸转移酶介导的dUTP缺口末端标记（TUNEL）法来研究变态幼虫组织中的细胞凋亡。变态的最早期事件之一是棒状腺的大量凋亡性破坏。因此，尽管以前有一些相反的观点，腺体细胞不能存活下来参与最终内柱或任何其他幼虫后结构的发生。
In amphioxus larvae, the club-shaped gland is a tube connecting the pharyngeal lumen with the external environment. The functions of the gland and its fate during the larva-to-juvenile metamorphosis have long been controversial. Here we use a fixative including ruthenium red to preserve extracellular secretions (presumably glycoproteins) in late pre-metamorphic larvae. This procedure reveals reddish, fibrogranular material in the lumen of the club-shaped gland and in the pharynx adjacent to the gland's inner opening. This finding strengthens the idea that secretions of the club-shaped gland are exported to the pharyngeal lumen to help form a mucous trap for capturing food particles entering the mouth. We also use the terminal desoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) assay to study apoptosis in the tissues of metamorphosing larvae. One of the earliest events of metamorphosis is the massive apoptotic destruction of the club-shaped gland. Therefore, despite some previous opinions to the contrary, the cells of the gland do not survive to participate in the genesis of the definitive endostyle or any other post-larval structures.