• Applied Microscopy
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• v.32 no.2
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• pp.107-119
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• 2002

Early spermatocytes of U. unicinctus are found in cluster floating in the coelomic fluid. The spermatocytes in a cluster form a syncytium or cytoplasmic mass, but there are no indications that the cytoplasmic mass is a component of a somatic cell. This work suggested that this type of spermatogenesis can be subordinated to solitary spermatogenesis in the sense excluding structural and functional support of a somatic cell for sperm developments. The solitary spermatogenesis in U. unicinctus is different in appearances and developmental details of sperm organelles and stage distributions from that of localized spermatogenesis. The acrosomal rudiments and centrioles can be observed in the early single cells of spermatogonia and clearly disclosed in the primary spermatocyte. In the stage of secondary spermatocyte, the acrosomal precursor and the centrioles begin to move to each cytoplasmic poles. The polarities of the organelles are attained at stage of spermatids. The spermatocytes and spermatids are arranged circumferentially along the cytoplasmic mass in which some amorphological cytoplasmic components are included. The spermatids reveal to be detached from the cytoplasmic mass into coelomic fluid. It suggests that the spermatogenesis are progressed in support of coelomic fluid, and the fact take into consideration that the spermatogenic cells can be in vitro cultured without somatic cells and with supplements of coelomic fluid.

• Development and Reproduction
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• v.13 no.1
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• pp.25-33
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• 2009

The cycle of the seminiferous epithelium and development of spermatids of Apodemus speciosus peninsulae were observed using a light microscope. On the basis of developing spermatocyte and spermatid, the cycle of the seminiferous epithelium was divided into 9 stages. Type Ad spermatogonia were appeared in all stages ($I{\sim}IX$). The Ap, In, and B types of spermatogonia were appeared from stage I, II and III, and IV, respectively. In prophase of first meiosis, the leptotene spermatocytes appeared from stage V and VI, zygotene spermatocytes from stages I, II, VII, VIII, and IX, pachytene spermatocytes from stage III to VII, diplotene spermatocytes in the stage VIII, and secondary spermatocytes in stage IX. On the basis of morphology of spermatid head, developing of nuclear and acrosome and the morphological change of cytoplasm, the developing of spermatids was divided into 12 steps. Considering all the results, A. s. peninsulae displayed very similar result with A. agrarius coreae that is allied species when compare correct characters developing of spermatids with spermatogonia and appearance time of the spermatocyte. Appearance time of the same cell and number of spermatogonial generation was thought that characters of the species, and information may be useful in identifying the species.

• Proceedings of the Zoological Society Korea Conference
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• 2001.04a
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• pp.71-71
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• 2001

No Abstract, See Full Text

• Parasites, Hosts and Diseases
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• v.31 no.3
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• pp.183-192
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• 1993

A transmission electron microscopic study was performed to observe the ultrastructures of the male germinal cells and spermatozoa of Fibricola seoulensis. Spermatogonia were found in the periphery of the testis and characterized by large nuclei and comparatively little cytoplasms. Spermatocytes contained an oval to spherical nucleus. Their nuclear volume was little larger in comparative to that of cytoplasm, and the chromatin was comparatively little. The early spermatids were characterized by a great amount of cytoplasm, and numerous mitochondria encircled the nucleus. In a more advanced spermatids the electron-dense strands of chromatin appeared in the nucleus, and a pair of rootlet of the axoneme and a microtubule-organizing center (MTOC) were observed near the nucleus. The sectioned spermatozoa were found in the testis and the seminal vesicle. Their cross sectional views were divided into 6 types when they were distinguished on the basis of the morphology and components. The spermatozoa of F. seoulensis showed two flagella of 9+1 type axoneme.

• Korean Journal of Veterinary Research
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• v.32 no.3
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• pp.281-293
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• 1992

Classification of the cycle of seminiferous epithelia into 12 stages by the morphological changes in acrosomal system and evaluation of the relative frequency of stages and the cell association were histologically performed in the mature Korean native Jin-do dogs. The results were summarized as follows; 1. The minimum number of type A spermatogonia averaged 1.01 at stages I, while maximum number averaged 2.47 at stages XII. Some type A spermatogonia divided at stage XII to produce the type intermediate(IN) spermatogonia at the following stage I. The type IN spermatogonia divided at stage IV to produce the type B spermatogonia at stage V. 2. The type B spermatogonia divided at stage VI to produce the preleptotene primary spermatocytes at stage VII. The secondary spermatocytes observed at stage XII. The secondary spermatocytes observed at stage XII divided to give rise to the round spermatids at the following stage I. The numbers of the first spermatocytes and spermatids were almost constant, respectively, through all the cycles of seminiferous epithelium. 3. The acrosomal vesicle was invaginated to occupy one third to half of spermatid nucleus at the cap phase, which was different from that of rodent and ruminant spermatid nuclei. 4. The relative frequencies of stages I to XII of seminiferous epithelia cycle were 10.34, 4.84, 5.03, 8.22, 10.86, 6.63, 6.42, 18.88, 10.17, 6.18, 7.62% and 4.81%, respectively.

• Korean Journal of Animal Reproduction
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• v.20 no.1
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• pp.43-52
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• 1996

This study was carried out to establish the in vitro short-term culture system of developing male germ cells by purifing germ cells of various stages. The decapulated testicular cells were incubated with collagenase (lmg/ml) and try psin (2.5mg/ml) in HBSS. After separating male germ cell, the separated germ cells were stained with heamatoxylin/eosin and determined developing stages under light microscopy. The purity of pachtene spermatocytes a and round spermatid were 85%, respectively. Yield of total male germ cells was highly variable between individuals, with a mean value of 3.5 to 4.5 ${\times}$ 10$^7$ cells/testis. Viability of the cell was over 97% after separation. In DMEM medium, the optimal cell number for culture is approximately 1 x 10$^5$ cells/dish, but low cell den-sities than 1 ${\times}$ 10$^5$ cell/dish showed a decreased cell viability. Furthermore, about :36.8% of pac-hytene cells was successfully cultured for 6 days and some of cells were developed to secondary spermatids and round spermatids. Therefore, our data suggested that this culture conditions will be utilize as a feasible tools to produce tran-sgenic livestock using techniques such as intrac-ytoplasmic injection and cell fusion.

• Clinical and Experimental Reproductive Medicine
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• v.30 no.2
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• pp.127-133
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• 2003

Objective: The aim of this study was to investigate the morphological aspects of testicular tissue before and after freezing-thawing by light and transmission electron microscopy. Methods: Tissue biopsies were carried out on mouse testis for freezing. Samples in medium containing 20% glycerol were frozen by computer-controlled freezing program. The effect of freezing-thawing on the structural change of testicular tissues were examined by light and electron microscopy. Results: The freezing-thawing procedure had no significant effect on tubular diameter. However, it caused folding of the lamina propria, and notable damage to Sertoli cells, spermatogonia and spermatocytes. The cells were detached, desquamated from the basal lamina and had increased vacuolization. Round spermatids, elongated spermatids and spermatozoa were less affected, and most of them maintained their normal structure. Conclusions: The structure of spermatogonia, spermatocyte and basal compartments in seminiferous epithelium was significantly altered by freezing-thawing procedure of mouse testicular tissues. Thus, we need to develop a more reliable method for the cryopreservation of testicular tissues.

• Animal cells and systems
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• v.16 no.2
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• pp.104-113
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• 2012

The nucleolus is a distinct nuclear territory involved in the compartmentalization of nuclear functions. There is some evidence of a relationship between nuclear fragmentation during spermatogenesis and chromatoid body (CB) formation. The CB is a typical cytoplasmic organelle of haploid germ cells, and is involved in RNA and protein accumulation for later germ-cell differentiation. The goal of this study was to qualitatively and quantitatively describe the nucleolar cycle during the spermatogenesis of $Phrynops$ $geoffroanus$ (Reptilia Testudines), and compare this nucleolar fragmentation with CB formation in this species through the use of cytochemical and ultrastructural analysis. Qualitative analysis showed a fragmentation of the nuclear material after pachytene of the first meiotic division in the primary spermatocytes. Quantitative analysis of the nucleolar cycle revealed a significant difference in the number of nucleoli and in the size of the nucleolus between spermatogonia and early spermatids. Using ultrastructural analysis, we recorded the beginning of the CB formation process in the cytoplasm of primary spermatocytes at the same time as when nuclear fragmentation occurs. In the cytoplasm of primary spermatocytes, the CB was observed in association with mitochondrial aggregates and the Golgi complex. In the cytoplasm of early spermatids, the CB was observed in association with lipid droplets. In conclusion, our data show that the nucleolus plays a role in the CB formation process. During spermatogenesis of $P.$ $geoffroanus$, the CB is involved in some important biological processes, including acrosome formation and mitochondrial migration to the spermatozoon tail and middle piece region.

• Journal of Aquaculture
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• v.22 no.1
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• pp.5-10
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• 2009

Spermatogenesis in male yellow croaker Larimichthys polyactis was histologically investigated by sampling testicular tissue from $2{\sim}3$ years old wild fishes captured from the coast of Mok-Po, South Korea. Spermatogenesis was characterized histologically, and staged according to the most advanced type of germ cell present. Annual reproductive cycle was classified into the following successive 4 stages: spermatogonia from August to September (rest stage), spermatogonia and spermatocytes from October to December (growth stage), spermatogonia, spermatocytes and spermatids from January to February (maturation stage), spermatogonia, spermatocytes, spermatids and spermatozoa from March to May (spermiation stage IV), and regressing testis from June to July (degeneration stage).

• Applied Microscopy
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• v.28 no.2
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• pp.193-205
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• 1998

The Urechis unicinctus sperm and spermatogenic cells prepared from the testis are investigated to identify $\alpha-tubulin$ of axoneme microtubules using mouse monoclonal $anti-\alpha-tubulin$ as the first Ab and Gold(10nm) conjugated goat anti-mouse IgG as the Ab marker. The Ag-Ab reaction analyzed excellently the localization of $\alpha-tubulin$ and the gold particles incorporated with the proximal and distal centrioles, manchette microtubules, and flagellum. The gold particles can be also observed in the spermatogenic cells while the cells are still in sperm ball which is composed of a somatic cell and spermatogenic cells. The sperm ball is the functional unit of sperm production in U unicinctus testis. The spermatids are developed from the spermatogenic cells in the sperm ball and released into the testis cavity through a cortical cytoplasmic opening. The spermatid architectures are similar with the mature sperm of the testis cavity in aspects of shape of discoid acrosome, degree of nuclear condensation and ring type of mitochondrion. However, the distal centriole connecting with the flagella can be observed from the mature sperm while the both proximal and distal centrioles reveal only in the spermatids. The proximal centriole is directly connected with nuclear outer membrane during the stage of nuclear condensation and oriented perpendicularly to the distal centriole whose axis coinciding with the longitudinal axis of the spermatozoon. There are indications that the distal centriole is intimately associated with the polymerization of the flagellum. The manchette microtubules appear during spermatid development but the mature sperm have round head and no conspicuous middle piece.