• Development and Reproduction
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• v.1 no.1
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• pp.9-24
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• 1997

To investigate the process of spermiogenesis of the Korean eastern Daubenton's bat, Myotis daubentonii ussuriensis, the testis obtained from mature male bats was studied by transmission electron microscope and were based on the variety and diagnostic characters of cell organells. The results obtained from the present study are as follows. According to the differentiation of the cell organells, the spermiogenesis of the Korean eastern Daubenton's bat, M. d. ussuriensis, was divided into Golg, cap, acrosome, maturation and spermiation phases. Besides, these Golgi, cap, acrosome, and maturation phase were subdivided into the steps of early and late phases repectively and matruation phase was subdivided into step of early, mid and late phases. Therfore, the spermiogenesisof M. d. ussuriensis has been divided into a total of 11 phases. The chromatin granules began to condense at the early cap phase, regularized at the acrosome phase, and a perfect nucleus of sperm was formed at the maturation phase. The chromatoid body was occurred in the upper cytoplasm of nucleus at the early Golgi phase, and it was accurred the posterior cytoplasm of the nucleus at the early maturatio phase. The formation of sperm tail began to be develop in the early golgi phase, and completed at the spermiation phase. The fiber structure of middle piece was consisted of nine outer doublets and two central singlet microtubules and Nos. 1, 5, 6 and 9 in the outer dense were larger than the others(2, 3, 4, 7, 8).

• Applied Microscopy
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• v.25 no.1
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• pp.96-110
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• 1995

In order to clarify the process of spermiogenesis of the large-footed bat, Myotis macrodactylus, the testis and the epididymis obtained from mature male bats were examined by electron microscope. Based on the variety and diagnostic characters of organells, the spermiogenesis of the large-footed bat. Myotis macrodactylus could be divided into a total of nine phases. The results obtained from the present study are as follows. 1. The spermiogenesis of large-footed bat, Myotis macrodactylus was divided according to the level of fine structural differentiation into five phases, Golgi, cap, acrosome, maturation and spermiation phases, respectively; Golgi, cap, acrosome and spermiation phases were further subdivided into steps of early and late phase respectively and maturation phase has only one step. Hence, the spermiogenesis of the large-footed bat has been divided into a total of nine phases. 2. In the change of chromatin with nucleus, the chromatin granules are condensed in the whole part of nucleus at the late Golgi phase and completed at the maturation phase. 3. The sperm tail in the epididymis consists of nine outer doublets and two central singlet microtubles. Nos. 1, 5, 6, 9 of the outer dense fibers were larger than the others (2, 3, 4, 7, 8).

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.2
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• pp.596-602
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• 2016

Experiments were carried out examine short-term effects of human chorionic gonadotropin (hCG) and long-term effects of luteinising hormone releasing hormone analogue (LHRHa) on milt production of the tongue sole Cynoglossus semilaevis. In the first experiment, each fish was implanted with a blank cholesterol pellet (control), 100 and $200{\mu}g$ LHRHa per kg body weight. In the second experiment, fish were injected with either 100, 200, 400 and 800 IU hCG per kg body weight or same volume of marine fish Ringer's solution. In the first experiment, milt volume was increased in male implanted with $200{\mu}g$ LHRHa pellet compared with other groups at day 10. Injection of 400 and 800 IU hCG resulted in an increase in the milt volume at hour 96 after the treatment. Although statistical difference is unable to confirm because of small milt volume, compared with the control group, hormone pellet-treated groups had a reduction in the mean spermatocrit (Sct) and sperm concentration (Sc). The results suggest that the increase in milt volume is at least partially gonadotropin (GtH)-dependent and increased milt volume has a relationship with milt hydration.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.6
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• pp.466-471
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• 2006

We investigated the changes in body weight (BW), plasma sex steroid hormone profiles, and testicular development of cultured male eel Anguilla japonica during an artificial maturation process. Eels that received weekly intraperitoneal injections of eel's ringer solution containing human chronic gonadotropin (HCG) were examined. In the ringer-treated control, BW changes decreased slowly during the experimental period. Plasma testosterone (T), 11-ketotestosterone (11-KT) and $17{\alpha},\;20{\beta}$-dihydroxy-4-pregnen-3-one (DHP) levels In the control remained low and did not show significant changes. Moreover, all germ cells in the testes of the control were spermatogonia. In the HCG-treated male eels, however, BW changes increased gradually from the fifth week and then decreased slowly. The plasma T level increased rapidly (p<0.05) in the second week and then decreased slowly. The plasma 11-KT level increased dramatically (p<0.05) in the second week and was maintained until the end of the experiment. The plasma DHP level increased progressively from the second week and peaked in the eighth week (p<0.05). The testes of HCG-treated male eels were more developed than those of the control; most were at the spermatozoa and spermatid stages and showed active spermiation. Thus, spermatogenesis and spermiation in the cultured eel can be induced by repeated injections of HCG.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.40 no.6
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• pp.374-379
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• 2007

Two experiments were designed to examine short-term effects of human chorionic gonadotropin (hCG), and long-term effects of gonadotropin-releasing hormone agonist (GnRHa), $17{\alpha}-hydroxyprogesterone$ (17P), and $17{\alpha},20{\beta}-dihydroxy-4-pregnen-3-one\;(17,20{\beta}P)$, alone or in combination, on milt production of the starry flounder Platichthys stellatus. In the first experiment, fish were injected with either 200 IU hCG/kg body weight or the same volume of marine fish Ringer's solution (MFRS). In the second experiment, each fish was implanted with a blank cholesterol pellet (control), $200\;{\mu}g$ GnRHa, $500\;{\mu}g$ 17P, or $100\;{\mu}g\;17,20{\beta}P/kg$ body weight alone or in combination. In the first experiment, hCG injection resulted in an increase in the expressible milt volume and a decrease in the spermatocrit (Sct). After pellet implantation in the second experiment, the milt volume was increased in males treated with GnRHa, GnRHa+17P, or $GnRHa+17,20{\beta}P$. On day 7 after hormone pellet implantation, the milt volume began to increase, and on day 14, the milt volume in the $GnRHa+500\;{\mu}g$ 17P group was significantly higher than that in the control group. Compared with the control group, the hormone pellet-treated groups had a significant reduction in the mean Sct and sperm concentration (Sc) at day 7 after pellet implantation, while there were no differences in total sperm number. The results suggest that increases in milt volume are generally associated with decreases in Sct and SC, suggesting that the main mechanism for the increase in milt volume was milt hydration.

• Applied Microscopy
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• v.22 no.2
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• pp.97-117
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• 1992

In order to study process of spermiogenesis of the Korean greater horseshoe bat, Rhinolophus ferrumequinum korai, the cycle of seminiferous epithelium was examined by the light and electron microscope and the following results were obtained based on the epithelial cell differentiation. 1. Spermiogenesis occurred from early July to mid-Octber, and spermatogenic activity was vigorous from mid-August to late September. Spermatocytes including spermatogonia were found to be degenerated in only July. It is deduced that the degeneration serves as the mechanism to regulate effective use of energy to prepare for mating and hibernating periods, and regulation of breeding cycle. 2. Spermiogenesis of the Korean greater horseshoe bat was divided according to differentiation of the cell structure, into Golgi, cap, acrosome, maturation and spermiation phases; Golgi, cap and spermiation phases were further divided into two steps of early and late phase respectively, and acrosome phase into three steps of early, mid and late phases, and maturation phase has only one step. Hence, the spermiogenesis consists of ten phases. The first research was done in this article on the changes of chromatin with nucleus, the time of appearance and disappearance of chromatin granules, in case of Korean greater horseshoe bat (Rhinolophus ferrumequinum korai). Chromatin granule began to be condensed in late Golgi and the condensation proceeded to form an irregular mass of a electron-dense chromatin in a form of circular cylinder in the center of nucleus at the phase of maturation. Finally, the chromatin condensation proceeded and perfect nucleus of sperm with homogeneous density was formed when the sperm was separated from Sertoli cell. Therefore, appearance and disappearance of chromatin granules occurred in the period of time between late Golgi and maturation phase, The tail of sperm began to develop in early cap phase, Numerous lipid droplets were obseved in the cytoplasm of spermatids during the maturation phase, which seemed to be used as energy source necessary to make mature sperm during spermiogenesis.

• Development and Reproduction
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• v.17 no.2
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• pp.87-97
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• 2013

The seminiferous epithelium cycle and developmental stages of spermatids in Clethrionomys rufocanus were observed under a light microscope. The seminiferous epithelium cycle was divided into 8 stages. Type Ad spermatogonia appeared through all stages. Type Ap, In, and B spermatogonia appeared in stages I, II, III, and IV. In the first meiosis prophase, the leptotene spermatocytes appeared from stage V, the zygotene spermatocytes in stages I, VI, VII, VIII, the pachytene spermatocytes from stages II to VI, the diplotene spermatocytes in stage VII. The meiotic figures and interkinesis spermatocytes were observed in stage VIII. Developing spermatids were subdivided into 10 steps, based on the morphological characteristics such as the acrosome formation changes in spermatozoa, nucleus, cytoplasm, and spermiation changes. The C. rufocanus spermatocytogenesis and spermiogenesis results displayed similar results with Apodemus agrarius coreae and A. speciosus peninsulae. Considering all the results, the spermatogenesis may be useful information to analyze the differentiation of spermatogenic cells and the breeding season.

• Biomedical Science Letters
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• v.10 no.3
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• pp.275-283
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• 2004

The annual changes in testis weight and diameter of seminiferous tubules, and the seminiferous epithelium cycle of Tamias sibiricus were studied by light microscope. Testis weight and diameter of seminiferous tubule are significantly increased from January to July, and decreased rapidly to the size from August to December. Spermatogenesis occurs from January to July, and spermatocytogenesis are produced from August to December. The cycle of the seminiferous epithelium was divided into 12 stages during the development of spermatids as a changes of the nucleus and acrosomal structure, presence and/or absence of residual body, appearance and/or absence of sperm tail and meiotic figure and spermiation. The dark type spermatogonia (Ad) are appeared in all stages (I ~ XII), and the spermatids of step 10 are observed at I, II, X and XII stages. The spermatids of step 11 are appeared in III and IV stages, only the step 12 spermatid observed in V stage.

• Biomedical Science Letters
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• v.11 no.4
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• pp.545-553
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• 2005

The present study provides descriptions of the cellular associations of the seminiferous epithelium cycle in the Crocidura shantungensis. The cycle of the seminiferous epithelium was divided into 14 stages, and developing spermatids were subdivided into 15 steps. The Golgi phase occurs the first two steps, and the cap phase had the next four consecutive steps. The acrosomal and maturation phases were consisted of steps $7\~14$, and the remaining one step consisted the spermiation phase. The Ad type of spermatogonia was observed whole stages, and Ap, In and B spermatogonia were observed from stage II to stage VI. The preleptotene, leptotene and zygotene of primary spermatocytes were observed from VII to XIV stages, and pachytene spermatocyte was observed from I to XII stages. The diplotene spermatocyte was observed XIII stages, and meiotic figures and secondary spermatocytes were observed stage XIV. Our results provide the foundation for a variety of future studies of the spermiogenesis of C. shantungensis.

• Journal of Veterinary Clinics
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• v.16 no.2
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• pp.448-453
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• 1999

The three-dimensional structure of the Sertoli cell in the Korean native bull was investigated by scanning electron microscopy. Morphologically, four types of Sertoli cell processes were evident: 1) sheet-like processes, 2) sleeve-like processes, 3) bough-like processes and 4) finger-like processes. The sheet-like processes rested upon more than half of the surface of each spermatogonia, spermatocyte and spermatid. Sleeve-like processes, bough-like processes and finger-like processes are observed in the middle and apical portion of seminiferous tubule. All Sertoli cell processes are originated from Sertoli cell column. Just before spermiation, the apical sheet-like processes are shifted from their position at the spermatid head, and bough-like processes covered the disengaged residual body, after which the residual body was no longer evident in the tubule. Though the mechanism for this elimination is not known, the process suggests a reciprocity between the Sertoli and germ cells.