The placental analogue and the pattern of sexual reproduction in the cheilostome bryozoan Bicellariella ciliata (Gymnolaemata).
The placental analogue and the pattern of sexual reproduction in the cheilostome bryozoan Bicellariella ciliata (Gymnolaemata).
复制标题
DOI：
10.1186/1742-9994-9-29
复制
发表时间：
2012-10-25
影响因子：
2.8
通讯作者：
Ostrovsky AN
中科院分区：
文献类型：
--
作者：
Moosbrugger M;Schwaha T;Walzl MG;Obst M;Ostrovsky AN
母体营养或胚外营养--妊娠期间营养从母体转移到胚胎--在脊椎动物中已广为人知并得到了深入研究，但在无脊椎动物中仍然知之甚少。本文着重研究了唇口苔藓虫Bicellariella ciliata（Linnaeus，1758）的卵子发生、胎盘营养和卵室形成的解剖学和超微结构。我们的研究旨在联合收割机结合这些方面的有性生殖成一个完整的图片，突出的原始胎盘样系统在苔藓动物生殖模式的进化中的作用。卵泡和卵母细胞的营养供应发生在卵子发生过程中。产生小的巨黄卵母细胞，胚胎通过简单的胎盘类似物（胚托）在卵细胞中营养。每一次育雏都伴随着胚托的肥大，在幼虫释放后胚托塌陷。营养物质通过胞吐作用（胚柄）和胞吞作用（胚）释放和吸收。胚胎缺乏专门的营养吸收区域，这发生在整个表皮表面。成熟卵母细胞与幼虫的体积增长率约为0.5%。十倍卵细胞是一个复杂的器官（不是通常认为的特殊多形体），由一个卵囊（保护囊）和一个卵囊泡（堵塞育雏腔的入口）组成，它们分别从远侧和可育的动物体发育而来。大卵黄卵子发生和胚外营养的结合允许归因于B。纤毛虫到繁殖模式IV的物种。然而，由于它的卵母细胞很小，这个物种代表了一个以前未描述的这种模式的变体，这似乎代表了一个过渡状态，从早期的母养型（大macrolecithal鸡蛋），以大量的（小microlecithal的）。总而言之，我们的研究结果大大增加和纠正了以前的作者获得的数据，提供了一个新的见解，我们的理解在无脊椎动物的营养进化。
Matrotrophy or extraembryonic nutrition – transfer of nutrients from mother to embryo during gestation – is well known and thoroughly studied among vertebrates, but still poorly understood in invertebrates. The current paper focuses on the anatomy and ultrastructure of the oogenesis and placentotrophy as well as formation of the brood chamber (ovicell) in the cheilostome bryozoan Bicellariella ciliata (Linnaeus, 1758). Our research aimed to combine these aspects of the sexual reproduction into an integral picture, highlighting the role of the primitive placenta-like system in the evolution of bryozoan reproductive patterns. Follicular and nutrimentary provisioning of the oocyte occur during oogenesis. Small macrolecithal oocytes are produced, and embryos are nourished in the ovicell via a simple placental analogue (embryophore). Every brooding episode is accompanied by the hypertrophy of the embryophore, which collapses after larval release. Nutrients are released and uptaken by exocytosis (embryophore) and endocytosis (embryo). Embryos lack specialized area for nutrient uptake, which occurs through the whole epidermal surface. The volume increase between the ripe oocyte and the larva is ca. 10-fold. The ovicell is a complex organ (not a special polymorph as often thought) consisting of an ooecium (protective capsule) and an ooecial vesicle (plugging the entrance to the brooding cavity) that develop from the distal and the fertile zooid correspondingly. Combination of macrolecithal oogenesis and extraembryonic nutrition allows attributing B. ciliata to species with reproductive pattern IV. However, since its oocytes are small, this species represents a previously undescribed variant of this pattern, which appears to represent a transitional state from the insipient matrotrophy (with large macrolecithal eggs) to substantial one (with small microlecithal ones). Altogether, our results substantially added and corrected the data obtained by the previous authors, providing a new insight in our understanding of the evolution of matrotrophy in invertebrates.
登录
查看更多内容
影响因子：
7.8
作者：
ABRAHAMS, SJ;HOLTZMAN, E
通讯作者：
HOLTZMAN, E
影响因子：
2.6
作者：
Byrne, M;Phelps, H;Potts, J
通讯作者：
Potts, J
影响因子：
1.2
作者：
Frick, JE
通讯作者：
Frick, JE
影响因子：
0.8
作者：
EGGLESTON, D
通讯作者：
EGGLESTON, D