The ultrastructure of escape organs: setose arms and cross-striated muscles in Hexarthra mira (Rotifera: Gnesiotrocha: Flosculariaceae)
The ultrastructure of escape organs: setose arms and cross-striated muscles in Hexarthra mira (Rotifera: Gnesiotrocha: Flosculariaceae)
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逃逸器官的超微结构：Hexarthra mira（轮虫目：Gnesiotrocha：花科）的刚毛臂和横纹肌
DOI：
10.1007/s00435-016-0339-2
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发表时间：
2017
期刊：
影响因子：
1
通讯作者：
Moore, Jeffrey
中科院分区：
文献类型：
--
作者：
Hochberg, Rick;Yang, Hui;Moore, Jeffrey
轮虫是捕食性浮游动物的常见猎物，为了避免被吃掉，它们进化出了一套防御和逃生策略。六角龙属的物种非同寻常，它有六个高度具刚毛的臂状附属物，这些附属物的功能是救赎跳跃通过水柱以躲避捕食。到目前为止，尽管这些逃逸器官在轮虫中是例外的，但还没有观察到它们的结构。在此，我们应用透射电子显微镜对臂状附属器及其刚毛及其肌肉供应的超微结构进行了研究。透射电子显微镜显示，臂是躯干被片的中空延伸，具有相似的超微结构。珠被完全合胞。合胞体顶端以双层质膜为界，其下是一层状的细胞质：顶层为薄的纤维状的胞质内层，底层为电子透光区，细胞器由基质膜和薄的基膜所包围。臂棘是体壁的中空外翻，没有特殊的超微结构。臂终止于初级刚毛，形成次生刚毛，所有次生刚毛都具有与手臂相似的超微结构。有两种类型的初级刚毛：无关节的刚毛是手臂被层的直接延伸，有关节的刚毛适合于手臂上的球窝类型的关节。这两种类型都没有神经，也没有肌肉供应。躯干和手臂上的骨骼肌都是横纹的，有明显的肌节。所有肌肉都有丰富的糖原颗粒和线粒体供应。一个复杂的肌小管系统供应肌原纤维，靠近糖原致密区域，提示了快速产生ATP的糖酵解途径以及肌肉收缩时迅速释放和重新摄取钙离子的途径。
Rotifers are common prey of predatory zooplankton and have evolved a suite of defensive and escape strategies to avoid being consumed. Species of the genusHexarthraare extraordinary in bearing six highly setose, arm-like appendages that function in saltational jumps through the water column to escape predation. To date, there are no observations on the structure of these escape organs despite their exceptionality within Rotifera. Here, we apply transmission electron microscopy (TEM) to study the ultrastructure of the arm-like appendages, their setae, and their muscle supply. TEM reveals that the arms are hollow extensions of the trunk integument with a similar ultrastructure. The integument is entirely syncytial. The syncytium is bordered apically by a double-layered plasma membrane beneath which is a layered cytoplasm: The top layer is a thin and fibrous intracytoplasmic lamina and the bottom layer is an electron lucent region containing cellular organelles bounded by a basal plasma membrane and thin basal lamina. Arm spines are hollow evaginations of the integument with no special ultrastructure. The arms terminate in primary setae that give rise to secondary setae, all of which possess an ultrastructure similar to the arms. There are two types of primary setae: unarticulated setae that are direct extensions of the arm integument, and articulated setae that fit into a ball-and-socket-type joint in the arm. Neither type is innervated nor supplied with muscles. The skeletal muscles in the trunk and arms are all cross-striated with distinct sarcomeres. All muscles are richly supplied with glycogen granules and mitochondria. A complex sarcotubular system supplies the myofibrils and is proximal to dense regions of glycogen, suggesting a glycolytic pathway for fast ATP production and the rapid release and reuptake of Ca2+for muscle contraction.
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影响因子：
3.6
作者：
U. Schramm
通讯作者：
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DOI：
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发表时间：
1987
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1968
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作者：
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横纹肌的超微结构。
影响因子：
0.8
作者：
M. Vye
通讯作者：
M. Vye