• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2002.11a
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• pp.75-75
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• 2002

The present study was conducted for the production of transgenic cloned cows by somatic cell nuclear transfer (SCNT) that secrete human prourokinase into milk. To establish an efficient production system for bovine transgenic SCNT embryos, the offset was examined of various conditions of donor cells including cell type, size, and passage number on the developmental competence of transgenic SCNT embryos. An expression plasmid far human prourokinase (pbeta-ProU) was constructed by inserting a bovine beta-casein promoter, a green fluorescent protein (GFP) marker gene, and a human prourokinase target gene into a pcDNA3 plasmid. Three types of bovine somatic cells including two adult cells (cumulus cells and ear fibroblasts) and fetal fibroblasts were prepared and transfected using a lipid-meidated method. In Experiment 1, developmental competence and rates of GFP expression in bovine transgenic SCNT embryos reconstructed with cumulus cells were significantly higher than those from fetal and ear fibroblasts. In Experiment 2, the effect of cellular senescence in early (2 to 4) and late (8 to 12) passages was investigated. No significant differences in the development of transgenic SCNT embryos were observed. In Experient 3, different sizes of GFP-expressing transfected cumulus cells [large (>30 ${\mu}{\textrm}{m}$) or small cell (<30 ${\mu}{\textrm}{m}$)] were used for SCNT. A significant improvement in embryo development and GFP expression was observed when small cumulus cells were used for SCNT. Taken together, these results demonstrate that (1) adult somatic cells could serve as donor cells in transgenic SCNT embryo production and cumulus cells with small size at early passage were the optimal cell type, and (2) transgenic SCNT embryos derived from adult somatic cells have embryonic development potential.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.56 no.3
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• pp.279-283
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• 2011

The immature embryos during seed development were examined to predict the suitable embryos for an efficient regeneration system. Five spring wheat genotypes and five winter wheat genotypes were tested using immature embryos as explants. Spring wheat genotypes showed much higher levels of plant regeneration than those of winter wheat genotypes. The highest frequencies of embryogenesis and regeneration were obtained when embryos at 13-14 days after anthesis (DAA) were used as explant and decreased using embryos at 21-22 DAA during seed development. Significant differences were also found for callus induction and regeneration as affected by immature embryo size. The regeneration efficiency was drastically decreased in spring and winter wheat genotypes when embryos larger than 2.0 mm of length were used. The optimum developmental stage and embryo length for regeneration efficiency were at 13-14 DAA and 1.0-1.5 mm, respectively. The selection of suitable embryos for the high frequencies of embryogenesis and regeneration leads us to efficient genetic improvement of wheat.

• Journal of Embryo Transfer
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• v.16 no.1
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• pp.29-34
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• 2001

To investigate the effect of co-transfer of trophoblastic vesicle (TV) with frozen-thawed in vitro Produced (IVP) bovine embryo on pregnancy rate, IVP blastocysts were transferred to synchronized recipients. Elongated blastocysts were recovered at Day 13 to 15, and dissected more than 4 pieces to removed the embryonic disc. Throphoblastic fragments were cultured for 48 hours to make throphoblastic vesicles (TVs). TVs were cryopreserved in ethylene glycol or vitrification solution and frozen-thawed TVs were co-transferred to recipients with frozen-thawed IVP embryos. 1 The recovery rate of elongated blastocyst on Day 13 to 15 was 22.5% (18/80) and the size of recovered elongated blastocysts was 0.2∼5.0mm. 2. Eighteen elongated blastocysts were dissected into 88 pieces and 61.4% of those pieces were formed to TV (54/88) 3. The viability of frozen-thawed TV in ethylene glycol was higher than in vitrified solution (92.8% vs. 68.8%) 4. The pregnancy rate in co-transfer with frozen-thawed TV and IVP blastocyst was better than transfer only IVP blastocysts (50.0% vs. 23.1%).

• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.10b
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• pp.21-21
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• 2003

An efficient plant regeneration system was developed for Hordeum vulgare L. cv Baegdong - an important Korean cultivar. The protocol was based on a series of experiments involving the sizes of mature embryos and the culture media. The embryo size is found to be critical for the establishment of embryogenic callus. Embryos of 1.1-1.5 mm size showed a much higher ability to produce embryogenic callus capable of regenerating green plants. The auxins picloram and dicamba proved effective in inducing callus from mature embryos. 2.5 mg $I^{-1}$ dicamba and 4.0 mg $I^{-1}$ picloram in Murashige and Skoog's (MS) medium was optimum for the induction of primary callus. The induced primary callus was loose and friable which ultimately developed into creamy white and compact callus after transferring into the fresh medium. Multiple shoots were induced in the MS medium supplemented with 6.0 g $I^{-1}$ maltose, 20 mg $I^{-1}$ sorbitol, 0.5 mg $I^{-1}$ 2,4-D and 1.0 mg $I^{-1}$ kinetin and the rate was 6.5 shoots per embryo. Regenerated plants were hardy and developed roots rapidly in the medium containing 0.2 $I^{-1}$ IBA. This efficient plant regeneration system provides a foundation for generating transgenic plants of this important barley cultivar.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2003.10a
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• pp.59-67
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• 2003

An efficient plant regeneration system was developed for Hordeum vulgare L. cv Baegdong - an important Korean cultivar. The protocol was based on a series of experiments involving the sizes of mature embryos and the culture media. The embryo size is found to be critical for the establishment of embryogenic callus. Embryos of 1.1-1.5 mm size showed a much higher ability to produce embryogenic callus capable of regenerating green plants. The auxins picloram and dicamba proved effective in inducing callus from mature embryos. $2.5\;m;I^{-1}$ dicamba and $4.0\;mg\;I^{-1}$ picloram in Murashige and Skoog's (MS) medium was optimum for the induction of primary callus. The induced primary callus was loose and friable which ultimately developed into creamy white and compact callus after transferring into the fresh medium. Multiple shoots were induced in the MS medium supplemented with $6.0\;g\;I^{-1}$ maltose, $20\;mg\;I^{-1}$ sorbitol, $0.5\;mg\;I^{-1}$ 2, 4-D and $1.0\;mg\;I^{-1}$ kinetin and the rate was 6.5 shoots per embryo. Regenerated plants were hardy and developed roots rapidly in the medium containing $0.2\;I^{-1}$ IBA. This efficient plant regeneration system provides a foundation for generating transgenic plants of this important barley cultivar.

• Journal of Embryo Transfer
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• v.1 no.1
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• pp.35-49
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• 1986

Recipients are an integral part of embryo transfer and they are expensive to maintain as a good recipient. Recipient management is one of the most important components in a successful embryo transfer program. Management includes selection and subsequent care of the animals. A good recipient is basically on "open" cows or heffers whose reproductive tract is capable of receiving one or two embryos and incubating it to term. Potential recipients should be always be healthy and cycling normally ranging from 18 to 23 days. A thorough veterinary examination is recommended for candidate of recipients and cattle for questionable health should be eliminated from the recipient herd. Age and size of recipients are particularly important considerations when heifers are used, because of most embryos available for transfer are from large dams and sires. Body condition can influence a recipient's production, reproduction and health. Obese and underconditioned cattle should be avoided for use. Transfer of fresh embryos especially requires precise synchronization of donors and recipients. For estrus synchronization, PGF$_2$$\alpha$ is injected twice 10 to 12 days apart and short4erm progestagen treatment is applied to potential recipient cattle by coil into vagina (PRID) or ear implant (Synchro-Mate-B). The highest pregnancy results are achieved in recipients at exact synchrony with donors or 12 to 24 hr earlier than donors. Estrus detection is a major factor in breeding efficiency. High accuracy can be achieved by use of heat mount detection alds or by obserbing cattle for 30-minute peroids 3 times daily. Assay progesterone in milk can be used to discrIminate between pregnant and nonprenant recipients. Rectal palpation on day 35 to 70 after is an accurate and safe method of pregnancy diagnosis. Embryonic mortality in recipients may be associated with factors such as high environmental temperature and nutritional or lactational stress in early lactation period. Achievement of short calving interval requires concentrated management activity during the first 90 days following calving. Acceptable candidate for a recipient should be routinely vaccinated for infectious diseases. Proper nutritional programs according to NRC requirements and body condition scoring system for recipient cattles are vital to the ultimate success of an embryo transfer program.r program.

• The Korean Journal of Zoology
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• v.28 no.4
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• pp.257-278
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• 1985

The effect of aromatic amino acids such as phenylalaine, tryptophan and tyrosine on somitogenesis at the early stage of chick embryo has been investigated morphologically using light and electron microscopy. Micrographs of aromatic amino acid injected chick embryo showed that an incomplete somite segmentation occurred and some decremental effect on the nervous system were observed. Somites were poorly developed and their size were variable. Electron micrograph of somatic cells from aromatic amino acid injected chick embryo showed that chromatins were coagulated, some of mitochondria were damaged, and nucleus were transformed considerably in some cases. The protein and nucleic acid levels and some enzyme activities of 15-day chick embryo which received the injection of 1mg of aromatic amino acid in 0.05 ml of saline 24 hours after the incubation were analyzed. Protein, DNA and RNA levels of the test group were not lowered significantly but the activities of enzymes for basic metabolism, such as lactate dehydrogenase, succinate dehydrogenase, malate dehydrogenase and glucose 6-phosphate dehydrogenase were considerably lowered as compared with those of control. From the present expeerimental results, it was tentatively suggested that the administration of amino acid might slow down the yolk granule degradation probably by feed back mechanism resulting in the disturbance of amino acid balance in the cell, which might give rise to impair normal metabolic pattern leading to abnormal somitogenesis to chick embryo at very early stage of development.

• Asian-Australasian Journal of Animal Sciences
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• v.13 no.5
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• pp.595-599
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• 2000

Fine wool sheep (n=18) maintained in a tropical environment were allocated to three treatment groups. Estrus was induced with two injections of $PGF_{2{\alpha}}$ (10 mg. im) at 10 days interval. Superovulation treatment started 2 days prior to the second injection of $PGF_{2{\alpha}}$. Each ewe was treated with a total dose of 25 units FSH (Super-OV) i.m. every 12 hover 3 days; Group 2 were also injected i.m. with 200 IU PMSG at the first injection of FSH; Group 3 was treated as in Group 2 and also with GnRH ($4{\mu}g$ Buserelin) at the onset of estrus. The ewes in estrus were mated with a fertile ram. Ovarian examination and recovery of embryo and ova were performed at laparoscopy and laparotomy on day 3 or 4 after mating. Data for onset of estrus, duration of estrus, number of corpora lutea (CL), number of unnovulated large follicle (LF), embryo recovery rate, embryo quality and fertilization recorded for the 3 groups. Ewes in the Group 1 set in estrus later (p<0.05; $50.0{\pm}7.29h$) than the ewes in Group 2 ($24.5{\pm}3.58$) and 3 ($32.5{\pm}3.58h$). The duration of estrus, ovarian size and ovarian response (number of CL and LF) did not differ significantly (p>0.05) among the 3 groups. The proportion of ewes with a superovulatory response (${\geq}2$ CL) was the lowest (50%) in Group 1 treated with FSH alone but ova/embryo recovery (100%) and fertilization (100%) was significantly (p<0.05) higher than Group 2 (58.3 and 85.7%, respectively) and Group 3 (48.6 and 50%, respectively). It is concluded that in tropical fine wool sheep, there is no difference in the 3 treatments for yield of good quality embryos but ovarian response and ovulation rate increased on additional use of PMSG and GnRH respectively to FSH alone.

• Journal of Ecology and Environment
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• v.31 no.1
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• pp.9-15
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• 2008

Growth and reproduction of Palaemon serrifer were described and analyzed in a population inhabiting tide pools in warm temperate waters in Korea. The water temperature varied greatly in the tide pools, ranging from 8$^{\circ}C$ to 27.8$^{\circ}C$ Population structure and growth were investigated using size frequency distribution data collected from January to December 2003. Sex ratios fluctuated, but were almost equal during the breeding period. Growth was continuous and size increased gradually throughout the year. Adult females were larger and grew faster than males. von Bertalanffy growth parameters for a one-year sample of females and males were estimated as $L_{i\ddot{A}}$ = 11.32, K = 0.311, $t_0$ = -0.4115 and $L_{i\ddot{A}}$ = 8.36, K = 0.228, $t_0$ = -0.9693 respectively. Breeding was seasonal, starting in May, peaking in August, and finishing by the end of August. The species showed continuous production of successive broods. Laboratory observation showed that females with embryos near hatching had ovaries filled with vitellogenic oocytes ready for spawning. The reproductive output (effort) of each female (mean number of eggs: $552{\sim}1355$) was not high. The mean embryo volume, $0.078mm^3$, is relatively small, indicative of low energy allocation to each embryo. Recruitment of juveniles was closely linked to the breeding period, beginning in September.

• Journal of Embryo Transfer
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• v.30 no.2
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• pp.91-97
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• 2015

Amphiregulin (AREG), a glycoprotein that is a member of the epidermal growth factor (EGF) family, is expressed by the porcine conceptus and endometrium. AREG genotypes were determined based on an SNP in the intron 3 of the gene. Contradictory effects of AREG genotypes on reproductive traits in different pig breeds were reported previously. G allele had undesirable effect on reproductive trait in Meishan breed, while it had favorable effects in Polish Landrace and Large White. We determined AREG genotypes of 179 pigs including the Duroc, Landrace, Yorkshire, Korean native pig (KNP), and Meishan breeds. Two new SNPs were identified near the previously reported SNP in the intron 3 of AREG. Frequencies of AREG alleles among the Duroc, Landrace, Yorkshire, and KNP sows were significantly different (p<0.001), indicating association between AREG genotypes and pig breeds. The first parity litter size was significantly affected by the breeds (p=0.014), but not by AREG genotypes (p=0.148). However, there were breed and AREG genotype associated trends in the first parity litter size. The first parity litter size appeared to be higher in Duroc and KNP sows with G allele, while it appeared to be lower in Landrace sows with G allele. Significant variability of AREG alleles among pig breeds, for the first time in Duroc and KNP sows, was identified. AREG genotypes may influence reproductive traits differentially for each breed and thus, AREG genotypes may need to be considered when sows are bred to increase litter size.