• The Korean Journal of Zoology
• /
• v.34 no.2
• /
• pp.217-227
• /
• 1991

Ultrastmctura changes of multivesicular bodies and mitochondria of oocytes of PseudopotamU- Ia occelata Moore were examined with transmission electron microscope in order to follow the process of yolk formation. Yolk granules begin to form at the previtellogenic stages of 50 $\mu$m diameter from multivesicular bodies. Small vesicles and membranous structures within the multivesicular bodies are fused to form the precursors of core bodies of yolk granules. Some vesicles from cytoplasm are also coalesced into the multivesicular bodies. Mature yolk granules are composed of electron-dense core bodies which are seperated from each other by electronopaque small vesicle-like structures. Structural changes of cristae into vesicular shapes and increase in electron density of matrix in mitochondria strongly suggested that mitochondria are in the process of transformation. The transformed mitochondria appear to be basic structures which later become multivesicular bodies.

• Journal of Microbiology
• /
• v.34 no.3
• /
• pp.220-224
• /
• 1996

Ultrastructural organization of encysting zoospores of Allomyces macrogynus was examined using the methods of cryofixation and freeze substitution. During enxcystment, obvious changes were observed at the surface of the plasma membrane and in the structure of gamma particles. Many multivesicular bodies associated with the plasma membrane were observed at early stages of encystment. After induction of encystment, vesicles were found within the gamma particles. These vesicles appeared to leave gamma particles after forming multivesicular bodies. This study suggests that the cell wall formation during encystment is mediated by the fusion of multivesicular bodies with the plasma membrane.

• Animal cells and systems
• /
• v.13 no.1
• /
• pp.49-57
• /
• 2009

For the study of the reproductive mechanism associated with the process of vitellogenesis, oocyte development and vitellogenesis during oogenesis in female Boleophthalmus pectinirostris were investigated by electron microscopic observations. The ovary consists of a pair of saccular structures with many ovarian lobules. In the early vitellogenic oocyte, the Golgi complex plays an important role leading to the formation of yolk vesicles containing carbohydrate yolks. At this time many pinocytotic vesicles containing yolk precursors are observed in the cytoplasm near the region of initial formation of the zona radiata. In the late vitellogenic oocytes, the multivesicular bodies, which are formed by modified mitochondria, are involved in the formation of the primary yolk granules. Precursors of yolk granules and multivesicular bodies develop to primary yolk globules with participation of pinocytotic vesicles. After primary yolk globules mix with each other, they develop into secondary and tertiary yolk globules. Based on these findings, vitellogenesis of B. pectinirostris occurs by way of the processes of endogenous autosynthesis and exogenous heterosynthesis. The process of autosynthesis involves the combined activity of the Golgi complex, mitochondria, and multivesicular bodies. However, the process of heterosynthesis involves pinocytotic incorporation of extraovarian precursors into the zona radiata of vitellogenic oocytes by way of the thecal cell layers and granulosa cells.

• Applied Microscopy
• /
• v.24 no.1
• /
• pp.41-58
• /
• 1994

The present studies were designed to determine the feasibility of using the rat tracheal epithelium as models for induction of aging. The ultrastructural and cytochemical changes of tracheal epithelium were investigated in rats at ages of five, twelve and twenty four months. Some major changes in the tracheal epithelium with advancing age were observed by electron microscopy. The results were summarized as fellow: 1. With the advance of age, lysosome, vacuole and multivesicular bodies were increased in number and numerous myelinoid bodies were observed in cytoplasm of ciliated cells. 2. In goblet cell, serous cell and brush cell lysosome and myelinoid bodies were increased in number with the advance of age, and an myelinoid bodies was often found within the secretory granule. 3. Cytochemical studies showed that acid phosphatase activities was observed in multivesicular bodies and lysosome, strong activities with the advance of age. And alkaline phosphatase activity are observed in microvilli, granule and lateral membrane of secretory granule cells, and strong activities with age. Consequently suggest that with the advance of age, tracheal epithelium show ultrastructural and cytochemical alteration of some kind of cell organelles in all kind of cell.

• Journal of Fisheries and Marine Sciences Education
• /
• v.28 no.5
• /
• pp.1231-1243
• /
• 2016

The ultrastructural study on oocyt development and the process of vitellogensis in the oocytes during oogenesis in female Pampus echinogaster were investigated by electron microscope observations. In the previtellogenic phase, in particular, several intermitochondrial cements appear in the cytoplasms of the chromatin nucleleolus oocyte and perinuclear oocyte. The number of intermitochondrial cements are associated with the multiplication of the number of mitochondria in the early developmental stage. In the early vitellogenic phase, the Golgi complex in the cytoplasm of the yolk vesicle oocyte is involved in the formation of yolk vesicles containing carbohydrate yolks. At this time, many pinocytotic vesicles containing yolk precursors (exogenous substances) by pinocytosis are observed in the cytoplasm near the region of initial formation of the zona pellucida. In the late vitellogenic phase, two morphological different bodies, which formed by the modified mitochondria, appeared remarkably in the yolked oocytes. The one is the multivesicular bodies and another is yolk precursors. The multivesicular bodies were transformed into the primary yolk globules, while yolk precursors were connected with exogeneous pinocytotic vesicles near the zona pellucida. After the pinocytotic vesicles were taken into yolk precursors, the yolk precursors were transformed into the primary yolk globules. Thereafter, primary yolk globules mixed with each other, eventually, they developed into secondary and tertiary yolk globules. In this study, vitellogenesis of this species occurred by way of endogenous autosynthesis and exogenous heteogenesis. Vitellogenesis occurred through the processes of endogeneous autosynthesis, involving the combined activity of the Golgi complex, mitochondria and multivesicular bodies formed by modified mitochondria. However, the process of heterosynthesis involved pinocytotic incorporation of extraovarian precursors (such as vitellogenin in the liver) into the zona pellucida (by way of granulosa cells and thecal cells) of vitellogenic oocytes.

• Applied Microscopy
• /
• v.31 no.2
• /
• pp.129-141
• /
• 2001

To investigate the spermiogenesis of the Saghalien Pygmy shrew (Sorex minutus gracillimus), the testis obtained from mature male shrew was studied by electron microscopy, and the following results obtained based on the morphological characteristics of cell differentiation of the seminiferous epithelium in the testis. According to the fine structural differentiation, spermiogenesis of S. minutus gracillimks was divided into Golgi, cap, acrosome, maturation and spermiation phases. Beside, the Golgi and cap phases were subdivided into three steps of early, middle and late phase respectively, and acrosome phase into two steps of early and late phase , and maturation and spermiation phases has only one step respectively. Thus, the spermiogenesis of S. minutus gracillimus was divided into a total of ten steps. The chromatin granules begin to be condensed in the acrosome phase, and a perfect nucleus of sperm was formed at the spermiation phase. Mancette were appeared from the late acrosome phase to the maturation phase. The formation of sperm tail began to develop in the late Golgi phase, and completed at the spermiation phase. Multivesicular bodies were appeared from the Golgi phase to the maturation phase, recognized with pale, pale and moderate, and dense at Golgi, cap and acrosomal and matulation phases respectively.

• Development and Reproduction
• /
• v.22 no.3
• /
• pp.213-223
• /
• 2018

Ultrastructural studies on oocyte differentiation and vitellogenesis in the oocytes of female Kareius bicoloratus were investigated by transmission electron microscopy. The Golgi complex in the cytoplasm is involved in the formation of yolk vesicles that contain yolk carbohydrates in the yolk vesicle of oocytes in the early vitellogenic phase. In this phase, many pinocytotic vesicles (PVs), which are formed by pinocytosis, contain yolk precursors (exogenous substances). These substances are associated with exogenous heterosynthetic vitellogenesis. In yolked oocytes in the late vitellogenic phase, two morphologically different bodies, which formed by modified mitochondria, appear in oocytes. One is a multivesicular body (synthesized by autosynthetic vitellogenesis), and the other is a yolk precursor (an exogenous substance formed by heterosynthetic vitellogenesis). The multivesicular bodies (MVB) are taken into the yolk precursors (YP) and are transformed into primary yolk globules. However, after the YP mix with exogenous PVs near the zona pellucida, they are transformed into primary yolk globules. Vitellogenesis of this species occurs via endogenous autosynthesis and exogenous heterogenesis. Vitellogenesis occurs through endogenous autosynthesis, which involves the combined activity of the Golgi complex, mitochondria and MVB formed by modified mitochondria. However, heterosynthesis involves pinocytotic incorporation of extraovarian precursors (such as vitellogenin in the liver) into the zona pellucida (via granulosa cells and thecal cells) of the yolked oocyte.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.35 no.2
• /
• pp.130-134
• /
• 2002

The ovary of the rockfish, Sebastes inermis was cystovarian condition and consists of numerous ovarian lobules. Previtellogenic oocytes were embedded in the connective tissue of the ovarian lobules. As the oocytes grows, it protruded into the ovarian cavity and form grapes cluster-like structure with egg stalk-like structure. Yolk granules and zona radiata were not observed in the embedded early oocytes about 20 $\mu$m in diameter. In the oocytes about 80 $\mu$m in diameter, yolk granules with electron dense were abundant in the ooplasm near the egg stalk-like structure. However, pinocytosis was not obsened in the pore canal system of the zona radiata. In this stage, microfilaments, developed endoplasmic reticula, tubular mitochondria, granular materials with low electron density and active multivesicular bodies were observed in the egg stalk-like structure. This results suggest that the egg stalk-like structure of the rockfish are related with the oocyte attachment and exogenous vitellogenesis of the intial vitellogenic oocyte.

• Applied Microscopy
• /
• v.27 no.3
• /
• pp.281-293
• /
• 1997

The effects of antimetabolite, 6-aminonicotinamide (6-AN), on ultrastrudural changes in the spinal cord of golden hamster were investigated. Intraperitoneal administration of 6-AN (10 mg/kg body weight) every two days gave rise to a marked reduction of about $30\sim40%$ in body weight after $26\sim28$ days ($13\sim14th$ injection). In the lesions of the spinal cord, neuroglial cells such as astrocytes and oligodendrocytes were severely damaged, but neurons and blood vessels were not affected by 6-AN. The myelin sheath was also affected by 6-AN. Vacuoles observed in the lesions were produced by the swelling and degenerating changes of neuropils and neuroglial cells. Numerous swollen mitochondria and cisterns of rough endoplasmic reticulum were observed in the watery cytoplasm of damaged neuroglial cells, but intermediate filaments were well preserved. Especially in the damaged astrocytes, the outer nuclear membrane were partially swollen and formed a halfmoonlike structure. It is suggested that as well as the multivesicular bodies protruding from the swollen dendrites, the conjugation of adjacent vacuoles also participated in the formation of large vacuoles.

• Applied Microscopy
• /
• v.6 no.1
• /
• pp.21-32
• /
• 1976

The origins and the functions of the multi vesicular bodies and the various structures of the membranes related to the cytolysomes were studied in the mycelium cells of Rhizopus nigricans, Aspergillus niger and A. ochraceus, in the hymenium and basidium cells of Agricus bisporus sand Rhizopogon rubesecens, in the cells of assimilation tissue of Marchtantia polymorpha and Pogonalum inflexum and in the mesophyll cells of Pteridium aqiulinum, Pinus densiflora, Ginkgo biloba and Panax ginseng fixed with glutaraldehyde-paraformaldehyde-$ OsO_4$. In Rhizopus nigricans, Aspergillus niger, A. ochraceus, Agricus bisporus sand Rhizopogon rubescens, the concentric multilamellar, multivesicular, myelin-vesicle-tubular and concentric parallel-lamellar complexes were originated from the plasmalemma, while in Marehantia polymorpha, Pogonatum inflexum, Pteridium aquilinum, Pinus densiflora, Ginkgo biloba and Panax ginseng, they were originated from plasmalemma and the cytoplasm. The structures originated from the plasmalemma may be grouped into multi vesicular body and myelin-like structure, both forming the secondary vacuoles or protruding into the central vacuoles and finally degrading, In some cases, endoplasmic reticulum within the cytoplasm encloses some part of the cytoplasm to form a circle where the membranous lamellae increase in number, while the enclosed cytoplasm decrease to be eventually replaced by the multilamellar structure which is released into the vacuoles and subsquently degraded. The structures originated from the cytoplasm are believed to be the cytosegresomes or cytolysomes closely related to the differentiation of the vacuoles. The possible fate of these structures are also discussed.