• ALGAE
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• v.35 no.4
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• pp.389-404
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• 2020

Red algal fertilization is unusual and offers a different model to the mechanism of intracellular transport of nuclei and polyspermy blocking. A female carpogonium (egg) undergoes plasmogamy with many spermatia (sperm) simultaneously at the receptive structure, trichogyne, which often contains numerous male nuclei. The pattern of selective transport of a male nucleus to the female nucleus, located in the cell body of the carpogonium, remain largely unknown. We tracked the movement of spermatial nuclei and cell organelles in the trichogyne after plasmogamy using time-lapse videography and fluorescent probes. The fertilization process of Bostrychia moritziana is composed of five distinctive stages: 1) gamete-gamete binding; 2) mitosis in the attached spermatia; 3) formation of a fertilization channel; 4) migration of spermatial nuclei into the trichogyne; and 5) cutting off of the trichogyne cytoplasm from the rest of the cell after karyogamy. Our results showed that actin microfilaments were involved in the above steps of fertilization, microtubules are involved only in spermatial mitosis. Time-lapse videography showed that the first ("primary") nucleus which entered to trichogyne moved quickly to the base of carpogonium and fused with the female nucleus. The transport of the primary male nucleus to the egg nucleus was complete before its second nucleus migrated into the trichogyne. Male nuclei from other spermatia stopped directional movement soon after the first one entered the carpogonial base and oscillated near where they entered trichogyne. The cytoplasm of the trichogyne was cut off at a narrow neck connecting the trichogyne and carpogonial base after gamete nuclear fusion but gamete binding and plasmogamy continued on the trichogyne. Spermatial organelles, including mitochondria, entered the trichogyne together with the nuclei but did not show any directional movement and remained close to where they entered. These results suggest that polyspermy blocking in B. moritziana is achieved by the selective and rapid transport of the first nucleus entered trichogyne and the rupture of the trichogyne after gamete karyogamy.

• 대한생식의학회:학술대회논문집
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• 1999.05a
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• pp.3-12
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• 1999

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.3
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• pp.353-357
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• 2008

A series of studies has been conducted to establish a base infrastructure for an ovarian follicle culture system in the porcine and this study was designed to develop an effective retrieval protocol of preantral follicles. Five different methods using collagenase type I (A) or IV (B, C1, C2 and C3), which employed different treatment durations and/or conditions, were employed and sliced ovarian tissue of prepubertal gilts was provided for the retrieval. A significant increase in total number of follicles retrieved was detected when collagenase IV (methods B or C) was used. In total, more ovarian follicles were retrieved by method B undertaking agitation and method C2 without the agitation than method C1 and C3, while the number of preantral follicles collected was the largest in method B. Neither incubation in 5% $CO_2$ in air atmosphere instead of the agitation nor increased duration of enzymatic treatment up to 120 minutes improved the efficiency of follicle retrieval. There were no differences in the number of follicles retrieved from intact ovaries and from used ovaries for oocyte collection. These results demonstrate the collagenase IV treatment with agitation is effective for retrieving porcine preantral follicles from the ovaries.

• Asian-Australasian Journal of Animal Sciences
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• v.22 no.3
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• pp.343-349
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• 2009

This study was designed to simplify a cryopreservation program for embryonic stem cells (ESCs) by selection of cooling method and cryoprotectant. Commercially available mouse E14 embryonic stem cells (ESCs) were cryopreserved with various protocols, and morphology and viability of the frozen-thawed ESCs and their reactive oxygen species (ROS) production were subsequently monitored. Post-thaw colony-formation of ESCs was detected only after a slow freezing using dimethyl sulfoxide (DMSO) by stepwise placement of a freezing container into a $-80^{\circ}C$ deep freezer and subsequently into -$196^{\circ}C$ liquid nitrogen, while no proliferation was detected after vitrification. When the simplified protocol was employed, the replacement of DMSO with a mixture of DMSO and ethylene glycol (EG) further improved the post-thaw survival. ROS generation in ESCs frozen-thawed with the optimized protocol was not increased compared with non-frozen ESCs. The use of fresh mouse embryonic fibroblasts as feeder cells for post-thaw subculture did not further increase post-thaw cell viability. In conclusion, a simplified slow-freezing program without employing programmable freezer but using DMSO and EG was developed which maintains cell viability and colony-forming activity of ESCs during post-thaw subculture.

• Clinical and Experimental Reproductive Medicine
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• v.17 no.2
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• pp.145-151
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• 1990

This study was carried out to elevating the pregnancy rate in infertile patient by Gamete intrafallopian transfer (GIFT). The GIFT program was performed from July 1988 to June 1990. Of the 131 cycles, the mean age of patient was 31.6 years and the mean duration of infertility was 5.3 years. 41 patients became pregnant, for a pregnancy rate of 31.3%. 5 preclinical abortions and 6 clinincal abortion was occured. 2 ectopic pregnanices and 1 combined pregnancy were occured. 7 twin pregnancies and 1 triplet were occured (multiple pregnancy rate;22.2%). 11 pregnancies were term delivered, 17 are ongoing pregnancies. GIFT may be considered as an alternative to in vitro fertilazation in infertility cases in which at least one fallopian tube is patent.

• 대한생식의학회:학술대회논문집
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• 1999.05a
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• pp.24-32
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• 1999

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2002.02a
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• pp.10-10
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• 2002

• 대한생식의학회:학술대회논문집
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• 2006.06a
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• pp.152.1-152.1
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• 2006

• KOREAN JOURNAL OF CROP SCIENCE
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• v.30 no.4
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• pp.455-459
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• 1985

This study is to select good diploid clones and develope them into FDR clones. Seventeen diploid clones were selected by tuber plants from the imported diploid potato seeds and from the progenies of the crosses between them. The characteristics of the selected clones were reported. Fifteen clones were crossed among them or open pollinated or bulk pollinated, and 18 selections were made from the seed progenies of these pollinations. Male and female unreduced gametes were searched by crossing 2x, 4x and by microtechnique. Only one clone, D6-21 was found to produce unreduced male gamete with the rate of 27-30% by FDR. Unreduced female gamete has not been found among these diploids.

• Korean Journal of Animal Reproduction
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• v.23 no.4
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• pp.353-358
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• 1999

Four important attributes for successful fertilization by a spermatozoon are (ⅰ) correct morphology, (ⅱ) correct presentation of egg recognition and fusion molecules, (ⅲ) progressive motility and (ⅳ), correct transfer of signalling molecules from sperm to egg for activation of development. In this presentation, these topics will be described and illustrated with emphasis on the endogenous control mechanisms that enable spermatozoa to respond to external signals. (omitted)