Development of the lateral musculature in the teleost, Brachydanio rerio: a fine structural study.
Development of the lateral musculature in the teleost, Brachydanio rerio: a fine structural study.
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硬骨鱼、斑马鱼外侧肌肉组织的发育：精细结构研究。
作者：
R. Waterman
通过光学和电子显微镜检查了硬骨鱼（Brachydanio rerio）中体区域的成体和六个发育阶段的外侧肌肉组织。描述了成人外侧肌肉组织的两个主要部分：（1）浅层部分，由具有高脂肪含量和琥珀酸脱氢酶（SDH）活性的小而深色纤维组成； (2) 深层部分主要由较大、苍白的“深层纤维”组成，显示出很少的 SDH 活性，并且含有很少的脂肪。一些“中间纤维”也存在于水平隔膜附近的深部。所有细胞类型的肌原纤维在超微结构上都相似。
中体体节的肌节分化的总体轮廓已经建立。肌生成开始于 20 体节阶段和 25 体节阶段之间的体节内侧表面，并横向进展。在孵化前不久，肌节包含两种结构不同类型的年轻肌肉细胞。这两种肌肉细胞群在幼虫和鱼苗中的出现支持了这样的假设：它们发育成成体外侧肌肉组织的浅层和深层部分。中间纤维群在 2 1/2 个月时出现。在 33 体节胚胎中，体节最外侧的细胞形成一层覆盖外侧肌节表面的扁平细胞，并被认为形成该物种的皮节。
The lateral musculature in the midbody region of the teleost, Brachydanio rerio, was examined by light and electron microscopy in the adult and six developmental stages. Two main divisions of the adult lateral musculature are described: (1) a superficial portion composed of small, dark fibers with high fat content and succinic dehydrogenase (SDH) activity; and (2) a deep portion composed principally of larger, pale, “deep fibers” showing little SDH activity and containing little fat. Some “intermediate fibers” are also present in the deep portion near the horizontal septum. Myofibrils of all cell types appear ultrastructurally similar.
A general outline of myotomal differentiation has been established for the midbody somites. Myogenesis begins at the medial surface of the somite between the 20- and 25-somite stages and progresses laterally. Shortly before hatching, the myotome contains two structurally dissimilar types of young muscle cells. The appearance of these two muscle cell populations in larvae and fry supports the hypothesis that they develop into the superficial and deep portions of the adult lateral musculature. The intermediate fiber population is present by 2 1/2 months. The most lateral cells of the somite form a layer of flattened cells covering the lateral myotomal surface in the 33-somite embryo, and are considered to form the dermatome in this species.