皱纹盘鲍眼部组织的显微及亚显微结构观察

采用组织学和电镜的方法,对皱纹盘鲍(Haliotis discus hannai Ino)的眼部组织进行了光镜和电镜观察,以期为进一步从分子生物学角度解析鲍对光照的生理响应机制提供组织学与细胞学基础。结果发现,眼部组织由外至内依次为视网膜色素上皮细胞层、外核层、光感受器内节、内核层、黑色素颗粒沉积层、视觉纤维层。组织表面布满乳头状突起,每一乳状突起的顶端均具有一簇或两簇纤毛环。疏松结缔组织和平滑肌纤维等是组织内的主要成分,结缔组织间分布的胶原纤维等对保持细胞的弹性和韧性具有重要的作用。研究结果显示了鲍的眼部组织在感受和辨识外界光环境因子中的重要作用,也为鲍养殖生产中的光环境因子优化和调控、深入探讨鲍对光照的生理应答机制提供了形态学依据。

Light and electron microscopic study of the eye of Haliotis discus hannai Ino

Light is a key environmental factor that influences the growth, culture and survival of aquatic organisms. In the present study, the eye tissues ofHaliotis discus hannaiIno were observed under the light microscope, scan-ning electron microscope and transmission electron microscope to provide an enhanced histological and cytologi-cal basis for analysis of the physiological response mechanism of abalone to light from the perspective of mo-lecular biology. Findings show that the eye tissues, from the outside to the inside, are: retinal pigment epithelium, outer nuclear layer, inner segment, inner nuclear layer, melanin granules sediment and optical fiber layer. Connec-tive tissue mainly exists between the epithelium and the outer nuclear layer, and a portion of the connective tissue nucleus is a darker color. The optical fiber layer mainly comprises the light red reticular nerve fibers which gradually become dense from the outside to the inside. The front ends of eye tissues are cylinder-shaped with an obvious circular depression, in which the reticular nerve fibers are mostly found. The surface of the eyestalk com-prises a large number of reticular fibers where the cavities of various sizes are densely distributed. The surfaces of eye tissues are covered with papillae and the top of every papilla has one or two clusters of ciliary rings. The ex-istence of desmosomes between adjacent cells can be clearly seen, and these can limit the expansion of cells and closely link them. Nucleiare found in various shapes and the double-layer nucleus is tightly enveloped by the cell membrane, which contains euchromatin and a few heterochromatin. Myofibrils are widely distributed and are composed of a large number of myofilaments closely arranged along the myofibrils; however, no obvious connec-tion is formed between them. Loose connective tissue, smooth muscle fiber and others are main components in the tissues. Collagenous and other types of fibers distributed between the connective tissues play a key role in main-taining the flexibility and toughness of cells. Mitochondria, Golgi apparatus and lysosomes are also widely dis-tributed in supporting cells. Amoebocytes are uniquely shaped and distributed between the loose connective tis-sues with pseudopodia and a large number of high electron density particles. Many melanin granules are densely distributed in the cytoplasm; these can prevent strong light from damaging the optical cells, and they also stabilize the internal environment of the retina. Findings demonstrate the significant role played by the optical tissues of the abalone in sensing and identifying external light environmental factors. They also provide a morphological basis for the optimization and regulation of light environmental factors in aquaculture production, as well as an in-depth discussion of the abalone’s physiological response mechanism to light.