• Clinical and Experimental Reproductive Medicine
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• v.24 no.1
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• pp.1-11
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• 1997

It is well known that the zona pellucidae of mouse oocytes become "hardened" when they are allowed to mature in vitro in the absence of serum components. To see if oocytes already undergone meiotic resumption in vivo exhibit similar zona hardening, hardening of ZP of cumulus-enclosed oocytes(CEOs) was examined after culture in vitro since their release from follicles various hours after hCG injection. When CEOs matured in vivo for 3h or longer were subjected to culture in vitro for 14h with BSA alone, zona hardening was significantly reduced compared to those cultured in vitro from the begining of maturation. However, when CEOs matured in vivo for 5h were freed from cumulus cells and then cultured in vitro with BSA alone, little reduction of zona hardening was observed. Preincubation of CEOs for 5h with fetuin, one of the well known inhibitor of in vitro zone hardening, did not prevent zona hardening during its subsequent culture of CEOs for 14h without fetuin. However, when CEOs precultured with both fetuin and PMSG for 5h and then further cultured with BSA alone for 14h, zona hardening was dramatically reduced. Under these conditions, the expansion of cumulus cell was observed. In addition, CEOs cultured with both BSA and dbcAMP to prevent their meiotic resumption showed a significant increase of zona hardening. Whether the observed zona hardening was correlated with the conversion of ZP2 to $ZP2_{f}$ was examined. Zona pellucida, isolated from CEOs matured for 5h in vivo and then further cultured with BSA alone was subjected to SDS-PAGE. Most of ZP2 molecules from these CEOs did not undergo conversion from ZP2 to $ZP2_{f}$. From these results, it is concluded that CEOs undergone meiotic resumption in vivo do not exhibit zona hardening when they were subsequently cultured in vitro without serum components. It appears that cumulus cells play an important role in this phenomenon.

• Korean Journal of Animal Reproduction
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• v.25 no.4
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• pp.317-325
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• 2001

This study investigated the effect of ferrous sulfate (Fe$^{2+}$) and/or ascorbic acid (Asc) on fertilizing ability in vitro of frozen-thawed boar spermatozoa. Using chlortetracycline (CTC) fluorescence, the spermatozoa was treated in preincubation medium with control, Fe$^{2+}$(1 mM), Asc (0.5 mM) and Fe$^{2+}$Asc to assessed for acrosome reaction, and the oocyte penetration test to determine whether the Fe$^{2+}$ and/or Asc can promote the penetration ability in vitro. When frozen-thawed spermatozoa was washed with preincubation medium, there were significantly (P ＜ 0.05) more acrosome-reacted in medium with Fe$^{2+}$Asc (38%) than control (27%). The penetration rates were also significantly (P ＜ 0.05) higher in medium with Fe$^{2+}$Asc (76%) than control (55%). Next, the lipid peroxidation of sperm was evaluated on the basis of malondialdehyde production following same treatments. The addition of Fe$^{2+}$Asc to sperm suspension increases the formation of malondialdehyde. However, there were not significantly different under the all conditions. The sperm suspension were also treated with control, Fe$^{2+}$, Asc and Fe$^{2+}$/Asc and assayed for sulfhydry1(-SH) group content. In the Fe$^{2+}$/Asc group, sperm-SH group were higher than another groups. In spermatozoa treated with Fe$^{2+}$ and/or Asc, however, no changes in sperm -SH-groups were detected when compared to controls. In another experiment, the activity of sperm binding to zona pellucida was evaluated through binding to salt-stored porcine oocytes. In control and Asc treatment groups, sperm binding to zona pellucida were significantly (P ＜ 0.05) higher than in medium with Fe$^{2+}$. On the other hand, there is not a significant increase in binding to zona pellucida with spermatozoa treated by Fe$^{2+}$/Asc. In summary, the present study suggests that Fe$^{2+}$/Asc causes an enhancement in fertilizing ability that is associated with penetration rate increased without change of spermatozoa binding capacity to homologous zona pellucida.o homologous zona pellucida.

• Korean Journal of Animal Reproduction
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• v.21 no.2
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• pp.85-93
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• 1997

These experiments were carried out to examine the development capacity of sexed and then bisected embryo from 8-cell to morula stage. Antisera to histocompatibility-Y(H-Y) antigen were prepared in inbred SD female rat by repeated immunization of spleen cell or testis supernatant from males of same strain. Male and female embryos were separated by delaying development of embryos against H-Y antibody. After sexing, rabbit embryos were bisected and aggregated. The results obtained from the these experiments were summuerized as follows: 1. When mouse and rabbit 8-, 16-cell and morular embryos were culature in H-Y antiserum, the ratio of embryo which has developed to hatching blastocyst was 53.4, 46.3 and 57.4% in mouse embryos, and 49.0, 52.0 and 61.0% in rabbit embryo, respectively. The ratio of mouse and rabbit embryos developed to hatching blastocyst showed nearly natural sex rate(50%), except rabbit mourla showed a little higher ratio(61.0%) as compared to natural sex ratio. 2. When rabbit demi-embryos from 8-, 16-cell embryo and morula were cultured, the percentage of demi-embryos was 70, 68 and 58% without zona pellucida removed, and 62, 69 and 51% with zona pellucida. The rate of aggregation was higher in 8- and 16-cell demi-embryos than in morula demi-embryo. 4. When sexed-demi-embryo was aggregated with another demi-embryo with demi-embryo with same sex, the rate of embryo developed to blastocyst was 60, 50 and 25%, respectively. Eight-cell demi-embryo showed highest rate. In conclusion, it showed that H-Y antiserum which was made by rat spleen cell enabled sexing rabbit embryos. And when rabbit sexed 8-, 16-cell and morula demi-embryo were aggregated, they were developed to eu-blastocyst which suggested the potential of sexed embryo manipulation.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.13-13
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• 2001

This study was undertaken to evaluate the effects of catalase using xanthine (X) - xanthine oxidase (XO) system on in vitro maturation and fertilization in pig. When follicular oocytes were cultured in maturation medium with X and/or XO, the maturation rates were not significantly different between in medium with and without catalase despite of different culture periods. However, significantly (P<0.05) higher maturation rates were obrained in culture with X-XO system. The rates of degenerated oocytes were increased with culture periods prolonged, and were significantly (P<0.05) higher in medium without than with catalase at 120 h of culture. On the other hand, the parthenogenetic oocytes were observed with high proportions at 72 h of culture, hut were not different in medium with and without catalase at various times of culture. In another experiment, the frozen-thawed boar spermatozoa treated with X-XO system for in vitro fertilization. The penetration rates were higher in medium with that than without catalase during the in vitro fertilization with, none (P<0.05), XO and X＋XO. On the other hand, when sperm were treated with none, X, XO and X＋XO, lipid peroxidation were higher in medium without that than with catalase. However, the changes in sperm penetration and lipid peroxidation showed opposite patterns. The sperm suspensions were also treated with X and/or XO for assay of sulfhydryl (-SH) group content. Under the above all conditions, sperm-SH group were higher detected In medium with that than without catalase. The activity of sperm binding to zona pellucida was also evaluated through binding to salt-stored porcine oocytes. In control group, sperm binding to zona pellucida were higher than in medium with X, XO and X＋XO groups. No significant differences, however, were observed between medium with and without catalase. In conclusion, the exposure of follicular oocytes and spermatozoa to X-XO system may be caused stimulating in vitro maturation and fertilization in pig. This work was supported by grant No. 2000-1-22200-001-3 from the Basic Research Program of the Korea Science & Engineering Foundation.

• Journal of Embryo Transfer
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• v.9 no.1
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• pp.43-48
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• 1994

This study was carried out to produce monozygotic twin calves by transfer of bisected embryos. Four Korean native cattle donors were superovulated with FSH and flushed to collect embryos on day 6 or 7 of the estrus cycle. Morula and early blastocyst embryos showed 1 or 2 grade were bisected with microblade and each set of demi-embryos without zona pellucida were transferred nonsurgically to 10 recipients respectively. The results obtained were as follows; 1. Twenty four demi-embryos (92.3%) were separated from 13 original embryos and among them 20 demi-embryos (83.3%) had normal appearance without severe damage. 2. Four sets of fresh demi-embryos were transferred to 4 recipients and one recipient was twin pregnant 3. Six sets of frozen-thawed demi-embryos were transferred to 6 recipients. Two recipients were pregnant, one of them twin.

• Clinical and Experimental Reproductive Medicine
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• v.45 no.1
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• pp.25-30
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• 2018

Objective: This study conducted a preliminary examination of the effects of three-area laser-assisted zona thinning (LAZT) during the cleavage stage of embryo development on the hatching process in human in vitro fertilization-embryo transfer (IVF-ET) with subjects of advanced female age or frozen-thawed (FT) embryos. Methods: Eight-cell stage embryos were treated with LAZT in three areas of the zona pellucida at $120^{\circ}$ intervals. The control group was embryos without LAZT. Of the 72 consecutive fresh cycles and the 28 FT embryo transfer cycles, the patients in 55 fresh cycles and 17 FT cycles declined LAZT, and those cycles were defined as the control group. Results: In the fresh cycles, the pregnancy rates were similar in the LAZT and control groups. However, in the FT cycles, the pregnancy rate was significantly higher in the LAZT group than in the control group (45.5% in the LAZT group vs. 23.5% in the control group, p< 0.05). Conclusion: These results show that multi-area LAZT resulted in significantly improved pregnancy outcomes in human 8-cell embryos compared to controls.

• Korean Journal of Animal Reproduction
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• v.19 no.2
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• pp.129-134
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• 1995

This study was carried out to investigate on the survival rate and in vitro developmental rate of bisected porcine embryos and immature oocytes by manipulator and micropipette. Bisected embryos and immature oocytes cultured for 1∼5 days in TCM 199 medium with 20% FCS. Survival rate was defined as development rate on in vitro culture or FDA-test. The results are summarized as follows ; 1. The survival rate of bisected porcine embryos and oocytes were 26.1%, 22.7%, respectively. The survival rate of bisected embryos and oocytes was significantly lower than that of non-bisection embryos(62.5%). 2. The survival rate of bisected porcine embryos in cultured for 12, 24, 48, 72 hrs with 20% FCS＋TCM-199 medium were 26.9%, 19.2%, 19.2% and 11.5%, respectively. 3. The in-vitro developmental rate with and without zona pellucida of bisected porcine embryos by micromanipulator were 30.8%, 25.0%, respectively.

• Korean Journal of Animal Reproduction
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• v.25 no.4
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• pp.327-337
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• 2001

This study investigated the effects of superoxide dismutase (SOD) on lipid peroxidation and fertilizing ability in vitro of boar spermatozoa frozen-thawed. The percentages of motile sperm were highest when SOD of 10 units/$m\ell$ was added to washing medium for spermatozoa. However, the rates of motile sperm were not significantly different in different concentrations of SOD. On the other hand, the motile rates of sperm washed with SOD were lower in sperm inculbated for 120 min than 30 min regardless of the different concentrations of SOD. The percentage of spermatozoa that reached acrosome reaction were increased with incubation periods prolonged. No significant differences, however, were observed in acrosome reaction rates between sperm incubated with and without SOD supplementation for 0, 60 and 120 min. When oocyies inseminated with different concentrations of SOD, the penetration rates were significantly (P＜0.05) higher in medium with 1 unit/$m\ell$ than 0, 10 and 100 units/$m\ell$ of SOD. However, the proportions of polyspermit oocytes were significantly (P＜0.05) lower in medium with 10 and 100 units/$m\ell$ than 0 unit/$m\ell$ of SOD. In another experiment, the sperm suspension were also treated with different concentrations of SOD and were assayed far sulfhydryl(-SH) group content. In the groups treated with 100 units/$m\ell$ of SOD, sperm-SH group were higher than another groups. However, sperm-SH group content were not siginificantly different in spermatozoa treated with different concentrations of SOD. Under the same conditions, the lipid peroxidation of sperm was evaluated on the basis of malondialdehyde production. The addition of SOD to sperm suspension decreased the formation or malondialdehyde. However, there were not significantly different in sperm treated with different concentrations of SOD. The activity of sperm binding to zona pellucida was also evaluated through binding to salt-stored porcine oocytes. The sperm binding to zona pellucida were gradually increased with SOD concentrations added. The number of spermatozoa binded to zona pellucida were significantly (P＜0.05) higher in medium with 100 units/$m\ell$ than 0 units/$m\ell$ of SOD. These findings suggested that SOD cause an enhancement penetrarion ability and sperm zona binding in boar spermatozoa frozen-thawed.

• Korean Journal of Environment and Ecology
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• v.35 no.5
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• pp.503-524
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• 2021

A largemouth bass (Micropterus salmoides) is an ecosystem disturbance fish species at the highest rank in the aquatic ecosystem, causing a serious imbalance in freshwater ecosystems. Although various attempts have been made to eradicate and control largemouth bass, no effective measures were found. Therefore, it is necessary to find an approach to maximize the effective population reduction based on the unique characteristics of largemouth bass. This study used the transcriptome analysis to derive 182,887 unigene contigs and select 12 types of final target sequences for applying the CRISPR/Cas9 system in the genes of IZUMO1 and Zona pellucida sperm-binding protein, which are proteins involved in sperm-egg recognition. After synthesizing 12 types of sgRNA capable of recognizing each target sequence, 12 types of Cas9-sgRNA ribonucleoprotein (RNP) complexes to be used in subsequent studies were prepared. This study searched the protein-coding gene of sperm-egg through the Next Generation Sequencing (NGS) and edited genes through the CRISPR/Cas9 system to induce infertile individuals that produced reproductive cells but could not form fertilized eggs. Through such a series of processes, it successfully established a composition development process for largemouth bass. It is judged that this study contributed to securing the valuable basic data for follow-up studies to verify its effect for the management of ecological disturbances without affecting the habitat of other endemic species in the same water system with the largemouth bass.

• Journal of Embryo Transfer
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• v.8 no.1
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• pp.13-19
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• 1993

These experiments were carried out to determine the effect of pregnancy in bisected embryo. The embryos of ICR mouse were microsurgically bisected at morula and blastocyst stage using microsurgical blade attached a micromanipulator. These bisected embryos without zona pellucida were cultured up to blastocyst stage and cell count and diameter of stained blastomere, and transferred pseudopregnant mice. And the development of these bisected embryos was compared with the results of production of young of the corresponding intact embryos or cell stage. When the bisected mouse embryos were cultured in vitro for 20 to 24 hours in morula stage(77.2%) or 3 to 6 hours in blastocyst stage(84.1%), them were developed to the expanded blastocyst stage. There were no significant(P<0.05) differences in the development rate of bisected embryos between in morula and blastocyst stages. The embryo size of blastocyst developed in vitro from bisected embryo was small(P<0.05)than intact embryo. However, the number of blastomeres with bisected embryo (24.7+1.3and 21.5+1.2 respectively) were significantly(P<0.05) reduced, compared with that of intacted embryos(36.3+1.1 and 41.4+1.2 respectively). When compared with the result of pregnancy rate(63.6%) after surgical transfer of bisected morulae, a similar result(65.4%) was obtained with bisected blastocyst stage(P< 0.05). However, production of youngs (38.8%) after transfer of bisected morula, a similar result (38.1%) was obtained with bisected blastocyst stage (P<0.05).