• Journal of Embryo Transfer
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• v.26 no.4
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• pp.287-296
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• 2011

Mammalian fertilization is a complex cascade process consisting of sperm migration through the female reproductive tract, physiological changes to sperm such as sperm capacitation and acrosome reaction, and sperm-egg interaction in the oviduct in vivo. On the other hand, in vitro fertilization (IVF) is a process by which egg cells are fertilized by sperm outside the body: in vitro. IVF has been used for a variety of purposes in reproductive biotechnology for human and animals. The discovery of sperm capacitation in 1951 promoted the development of IVF technology. In the initial stage of IVF, sperm capacitation in preincubation medium was shown to be essential to fuse with eggs. Besides, sperms should detour some of the in vivo regulations for IVF. This review introduces a general mammalian fertilization process, including sperm capacitation, removal of cumulus matrix, acrosome reaction, and sperm-egg fusion and focuses on the roles of key biochemical molecules, signal mechanisms, and genes involved during IVF and novel results of sperm-oocyte interaction elucidated in various gene-knockout mice models.

• Korean Journal of Animal Reproduction
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• v.16 no.3
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• pp.199-208
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• 1992

These studies were carried out to investigate optimal physological conditions for in vitro fertilization (IVF) of mouse ova. The unfertilized ova were obtained by superovulation from ICR mice of 4 to 6 weeks old. Tyrode's 280 solution was used as basal media, and pH and osmolality of basal media were adjusted with the supplementation of sodium bicarbonate and sodium chloride, respectively. The optimal pH, and osmolality of culture media and the optimum period of sperm preincubation were examined in fertilization in vitro of mouse ova and the subsequent culture in vitro of embryos. The pH range of media examined was designed from 6.5 to 7.5 with 0.2 interval and the range of osmolality from 250 to 370 mOsm with 20 interval, and the period of sperm preincubation examined was 30, 60, 120, and 180 minutes. The ova developed to 2-cell embryosafter 26hrs. of incubation with preincubated sperm were evaluated as in vitro fertilized ones. The results obtained were summarized as follows: 1. The percentage of in vitro fertilized ova was highest (64.7%) in media of pH 7.1 and lowest (38.0%) in pH 6.7. No significant difference in % fertilized ova was found from the media of pH 7.1 to 7.5. Compared with the result from pH 7.1 medium, the pollyspermy was increased signifciantly (p<0.05) in the media of pH over 7.5 and below 6.9;, and the % degenerated ova was significantly (p<0.05) increased in the media of pH below 6.9. 2. The percentage of in vitro fertilized ova was highest (69.4%) in media of osmolality 330 mOsm and lowest (47.9%) in osmolality 250 mOsm. No significant difference in % fertilized ova was found from the media of osmolality 310 to 350 mOsm. Compared with the result from osmolality 330 mOsm in medium, the polyspermy aws increased significantly(p<0.05) in the media of osmolality over 350 mosmol and blow 290 mOsm, and the % degenerated ova was significantly (P<0.05) increased in the media of osmolality below 290 mOsm. 3. The percentate of in vitro fertlilized ova was highest (62.7%) in media of period sperm preincubation 180 min. and lowest (40.4%) in sperm preincubation 30 minutes. No significant difference in % fertilized ova was found from the media of sperm preincubation 120 to 180 minutes. Compared with the result from sperm preincubation 180 minutes in medium, the polyspermy was low differ no significantly(P<0.05) in the media of period sperm preincubation, and the % degenerated ova was signifciantly(P<0.05) increased in the media of sperm presincubation below 60 minutes.

• Proceedings of the KSAR Conference
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• 2002.06a
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• pp.50-50
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• 2002

During fertilization, morphological and molecular events in male and female chromatin are precisely controlled in time. However, little information is available on onset of pronuclear formation and first S-phase entry in the pig following intracytoplasmic sperm injection. To assess species specific paternal effect on the pronuclear formation and initiation of first S-phase in the pig, we examined time of onset of male and female pronuclear formation and onset of DNA synthesis in the oocytes following pig or mouse sperm injection. (omitted)

• Journal of Embryo Transfer
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• v.4 no.1
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• pp.21-27
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• 1989

Hydrogel chambers made from polymerized 2-hydroxyethyl methacrylate were used for in chamber fertilization. To determine whether sperm motility was preserved in the Hydrogel chamber, chambers which have rabbit sperm or frozen-thawed bovine sperm were transplanted inside of mouse peritoneal cavity and sperm were observed after recovering the chambers in the due time. As a result, it was determined that preservation of sperm motility was good. To determine whether in chamber fertilization was possible, chambers which have rabbit oocytes and sperm were transplanted inside of mouse peritoneal cavity and eggs were observed after recovering the chambers at 84 hr of preservation. As a result, the fact that fertilization and culture was occurred inside of the chamber was determined.

• Korean Journal of Animal Reproduction
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• v.16 no.3
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• pp.209-215
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• 1992

These studies were carried out to overcome 2-cell block and in vitro development to blastocysts in vitro fertilization of mouse embryos. The unfertilized ova were obtained by superovulation in ICR mice of 4 to 6 weeks old. Tyrode's 280 solution was used as basal media, and the pH range of media examined was designed from 6.5 to 7.5 with 0.2 interval and the range of osmolality from 250 to 370 mOsm with 20 interval, and the period of sperm preincubation examined was 30, 60, 120, and 180 minutes. The ova developed to 2-cell embryos after 26hrs of incubation with preincubated sperm were evaluatated as in vitro fertilized ones. The results obtained were summarized as follows: 1. The optimal ranges of pH and osmolality of culture media and of sperm preincubation time for in vitro development of in vitro fertilized ova to blastocyst were pH 7.1 to 7.3, 250 to 350 mosmol and 60 to 180 min, respectively. 2. With the media of pH 7.1, 310 mOsm and sperm preincubation period of 120min in another experiment of large sample size, the in vitro fertilized ova was found 66.5% and the in vitro development of in vitro fertilized ova to blastocyst was found 35.8%. From the above results it was concluded that the optimal conditions of pH and osmolality of the media for mouse IVF and embryo culture, and the period of sperm preincubation might be 7.1, 310 mOam and 120min, respectively.

• Journal of Radiation Protection and Research
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• v.31 no.1
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• pp.31-35
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• 2006

For the purpose of the biological effect in black mouse by neutron irradiation, mice were irradiated with 16 or 32 Gy neutron (flux: 1.036739E+09) by tying flat pose at BNCT facility on HANARO Reactor. And 90 days later of irradiation, physical changes of testis and testis tissue were examined. There were no weight changes but a little bit volume changes and sperm counts in the testes. Atrophy of seminiferous tubules irradiated with 32 Gy neutron is increased in number and severity and those in stage VI showed depletion of spermatogonia and pachytene spermatocytes compared to the non-irradiated control group. Testis damage of black mouse was not recovered after long time by 32 Gy neutron irradiation.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.41-41
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• 2001

Chromatin configuration and microtubule assembly were determined in porcine maturing and activated oocytes following intracytoplasmic sperm injection. Microtubule localization was confirmed using a mouse monoclonal antibody to $\alpha$-tubulin and detected using a fluorescent labeled goat anti-mouse secondary antibody. DNA was stained with propidium iodide. The image of microtubules and chromatin was captured using laser scanning confocal microscope. In germinal vesicle stage oocyte, sperm chromatin remained condensation and sperm derived microtubules were not observed at 8 to 12 h after sperm injection. At 24 h after injection, the sperm nucleus developed to the metaphase chromatin along the metaphase structure of female nucleus. In some metaphase I stage oocytes, sperm chromatin decondensed at 8 h to 12 h after injection, sperm aster was seen soon after sperm injection. At 24 h after sperm injection into metaphase I stage oocyte, male chromatin developed to the metaphase chromatin while female chromatin extruded first polar body and formed the metaphase chromatin. At 12 to 15 h after sperm injection into preactivated oocytes, condensed sperm nucleus was located in close proximity of female pronucleus. However, the condensed nucleus did not fuse with female pronucleus. In preactivated ocytes, injected sperm remained condensation, a few sperm organized small microtubular aster. Instead, maternal derived microtubules were organized near the female chromatin, which seem to move condensed male chromatin near to the female pronucleus. These results suggest that sperm nuclear decondensing activity and nucleation activity of centrosome during fertilization are cell cycle dependent. In absence of male functional centrosome, female origin centrosome takes over the role of microtubule nucleation for nuclear movement.

• Clinical and Experimental Reproductive Medicine
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• v.24 no.2
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• pp.187-192
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• 1997

The survival rate and motility recovered after cryopreservation of testicular spermatozoa in testicular sperm extraction (TESE)-ICSI program is low. The purpose of this study was to assess the availability and efficiency of mouse empty zona pellucida in cryopreserving human TESE spermatozoa. Mouse empty zonae pellucidae were obtained by extraction of cytoplasm with or without cytochalasin B treatment. Motile sperm from proven-fertile donor and two azoospermic patients after TESE were individually inserted into empty zona pellucida and cryopreserved. Two to five days after cyropreservation, the frozen sperm were thawed and the rates of recovery and motility were observed. The ooplasmic extraction rates of control (N=80) and cytochalasin B treated oocytes (N=80) were 94.0% and 96.2%, respectively (p>0.05). The post-thaw recovery rates of spermatozoa and rates of motility recovery of ejaculate (N=70) and testicular (N=70) sperm were 97.1%, 97.1% and 95.7%, 94.3%, respectively (p>0.05). The results of this study showed that the mouse zone pellucida is useful for cryostorage of single testicular spermatozoa.

• Korean Journal of Animal Reproduction
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• v.23 no.1
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• pp.19-27
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• 1999

This study was carried out to investigate the effect of intracytoplasmic injection of $Ca^{2＋}$ and human sperm extract on the parthenogenetic activation of mouse oocytes. The results obtained were as follows: 1. The mouse oocytes were injected with 10 pl of PBS medium containing 0, 1.7 and 5 mM calcium concentrations, respectively. Activation rate of the oocytes with formation of pronuc1ei and extrusion of the second polar bodies was 14.5, 9.8 and 14.9% at the above calcium concentrations, respectively. There were no significant differences in the activation rates among the calcium concentrations. 2. The mouse oocytes were injected with 10 pl of non-heated human sperm extract, and cultured for 12~15 h in the PBS media with the 0, 1.7 and 5 mM calcium concentrations, respectively. Activation rate(51.8%) of the oocytes at the 1.7 mM calcium concentration was significantly higher than those at the 0 and 5 mM calcium concentrations. 3. The mouse oocytes were injected with 10 pl of heated human sperm extract, and cultured for 12~15 h in the PBS media with the 0, 1. 7 and 5 mM calcium concentrations, respectively. No significant differences were found in the activation rates (11.8~17.0%) among the calcium concentrations. 4. The mouse oocytes were injected with 10 pl of PBS medium, non-heated sperm extract and heated sperm extract, and cultured for 12~15 h in the PBS media with 1.7 mM calcium concentrations, respectively. Activation rate (54.5%) of the oocytes injected with the non-heated sperm extract was highest. There were significant differences in the activation rates among the above injection materials (P＜0.05). 5. The mouse oocytes were injected with 10 pl of 1 and 6 days old non-heated sperm extracts, and cultured for 12＜15 h in the PBS media with 1.7 mM calcium concentrations, respectively. Activation rate(60.0%) of the oocytes injected with 1 days old sperm extract was significantly higher than that (11.1%) injected with 6 days old sperm extract. The results obtained in this study suggest that non-heated human sperm extract may contain sperm-associated oocyte-activating factor such as oscillin.

• 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.