• 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.

• Asian-Australasian Journal of Animal Sciences
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• v.28 no.11
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• pp.1565-1572
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• 2015

Porcine embryonic stem cells (pESCs) have become an advantageous experimental tool for developing therapeutic applications and producing transgenic animals. However, despite numerous reports of putative pESC lines, deriving validated pESC lines from embryos produced in vitro remains difficult. Here, we report that embryo aggregation was useful for deriving pESCs from in vitro-produced embryos. Blastocysts derived from embryo aggregation formed a larger number of colonies and maintained cell culture stability. Our derived cell lines demonstrated expression of pluripotent markers (alkaline phosphatase, Oct4, Sox2, and Nanog), an ability to form embryoid bodies, and the capacity to differentiate into the three germ layers. A cytogenetic analysis of these cells revealed that all lines derived from aggregated blastocysts had normal female and male karyotypes. These results demonstrate that embryo aggregation could be a useful technique to improve the efficiency of deriving ESCs from in vitro-fertilized pig embryos, studying early development, and deriving pluripotent ESCs in vitro in other mammals.

• Journal of Embryo Transfer
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• v.9 no.1
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• pp.111-116
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• 1994

This study was carried out to investigate the aggregation rate of isolated mouse 2-, 4- and 8-cell stage blastomeres in phytohemagglutinin(PHA) solution. The morphologically normal embryos were collected from the oviduct of superovulated female mouse by flushing with M2 and the zona pellucida of embryos were removed with 0.5% pronase. The blastomeres were isolated by pipetting after plunging into Ca++-Mg++free PBS for 20 min. The result showed that aggregation rate in 0.5% (84.9~93.1%) was higher than that in 1.0% PHA(76.0~82.1%). Optimal aggregation time was 60min (83.9~100.0%) when compared with 30min (78.8~87.5%). Developmental to blastocyst in recombinated blastomeres was higher under conditions of 0.5% PHA solution and 60-min aggregation than that under other conditions.

• Korean Journal of Veterinary Research
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• v.63 no.1
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• pp.3.1-3.9
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• 2023

The efficiency of somatic cell nuclear transfer (NT) in pigs is low and requires enhancement. We identified the most efficient method for zona pellucida (ZP) removal and blastomere aggregation in pigs and investigated whether the aggregation of NT and parthenogenetic activation (PA) of blastomeres could reduce embryonic apoptosis and improve the quality of NT-derived embryos by investigating. Embryonic developmental competence after ZP removal using acid Tyrode's solution or protease (pronase E). The embryonic developmental potential of NT-derived blastomeres was also investigated using well-of-the-well or phytohemagglutinin-L. We analyzed apoptosis in aggregate-derived blastocysts. The aggregation rate of protease-treated embryos was lower than that of Tyrode's solution-treated embryos (69.2% vs. 88.3%). No significant difference was observed between phytohemagglutinin-L and well-of-the-well (35.7%-38.5%). However, 2P1N showed a higher number of blastocysts compared to 3N (73.8% vs. 24.3%) and an increased blastocyst diameter compared to the control and 1P2N (274 ㎛ vs. 230-234 ㎛). In blastomeres aggregated using phytohemagglutinin-L, the apoptotic cell ratio was significantly higher in 1P2N and 3N than in 3P (5.91%-6.46% vs. 2.94%, respectively). Our results indicate that aggregation of one NT embryo with two PA embryos improved the rate of blastocysts with increased blastocyst diameter.

• Korean Journal of Animal Reproduction
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• v.24 no.4
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• pp.451-455
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• 2000

Gene targeting are very useful tools for the research on the gene function in vivo, mass production of foreign materials and biomedical approach of therapeutic process. But this process is very complicated and necessary highly skilled technique, because it is very different from ES cell origin, genetic background of embryo, and experimental conditions. We investigated the productivity ability of chimeric mouse after aggregation with TT2 ES cells. Increse of ES cell density caused gradual decrease in embryo development in vitro and in th $\varepsilon$ production of chimeric mice in vivo. One million ES cell density for the aggregation was very efficient to produce high percentage chimeric mice in their coat color. These results suggested that appropriate cell density plays a key role in the development and production of chimeric mice by a 8-cell aggregation method.

• The Korean Journal of Zoology
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• v.33 no.3
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• pp.310-321
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• 1990

To establish the in vitro culture system and quantitation for chondrogenesis, and to investigate the relationship between cell aggregation and chondrogenesis, chick limb bud mesenchymal cells of Hamburger-Hamilton stage 23/24 were micromass cultured in various cell densities. The chondrogenesis was assayed based on checking the alcian blue-stained nodule numbers, the amount of alcian blue extraded, the change in cell numbers, the rate of [35 S] sulfate incorporation and expression of type II collagen. Mesenchymal cells plated with an initial density of high (1 x 107 cells/ml)- and intermediates (5. $\times$ 106 cells/ml)-density were differentiated into cartilage. On the other hand, the cells of low density (2 x 106 cells/mi, 5 $\times$ 105 cells/ml) of stage 23/24 cells and the stage 18/19 cells in three kinds of cell density did not differentiate into cartilage even though the cells formed an aggregated core at the center of cultured mass. From these results and others obtained in this study, it can be stated that the stage 23/24 mesenchymal cells are likely to pass over the aggregation step and have the potentiality to differentiate into chondrocytes. Thus chondrogenesis in vitro can be observed when mesenchymal cells are plated over the threshold density of 5 $\times$ 106 cells/ml. Hyaluronidase (HAase) activity was relatively constant throughout the culture, suggesting that the role of HAase may not be important for the cells of stage 23/24.

• Molecules and Cells
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• v.38 no.12
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• pp.1096-1104
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• 2015

Particulate $matter_{2.5}$ ($PM_{2.5}$) is notorious for its strong toxic effects on the cardiovascular, skin, nervous, and reproduction systems. However, the molecular mechanism by which $PM_{2.5}$ aggravates disease progression is poorly understood, especially in a water-soluble state. In the current study, we investigated the putative physiological effects of aqueous $PM_{2.5}$ solution on lipoprotein metabolism. Collected $PM_{2.5}$ from Seoul, Korea was dissolved in water, and the water extract (final 3 and 30 ppm) was treated to human serum lipoproteins, macrophages, and dermal cells. $PM_{2.5}$ extract resulted in degradation and aggregation of high-density lipoprotein (HDL) as well as low-density lipoprotein (LDL); apoA-I in HDL aggregated and apo-B in LDL disappeared. $PM_{2.5}$ treatment (final 30 ppm) also induced cellular uptake of oxidized LDL (oxLDL) into macrophages, especially in the presence of fructose (final 50 mM). Uptake of oxLDL along with production of reactive oxygen species was accelerated by $PM_{2.5}$ solution in a dose-dependent manner. Further, $PM_{2.5}$ solution caused cellular senescence in human dermal fibroblast cells. Microinjection of $PM_{2.5}$ solution into zebrafish embryos induced severe mortality accompanied by impairment of skeletal development. In conclusion, water extract of $PM_{2.5}$ induced oxidative stress as a precursor to cardiovascular toxicity, skin cell senescence, and embryonic toxicity via aggregation and proteolytic degradation of serum lipoproteins.

• Microbiology and Biotechnology Letters
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• v.46 no.4
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• pp.372-376
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• 2018

To investigate the bio-activities of lotus (Nelumbo nucifera Gaertner), ethanol extracts were prepared from different parts of lotus, including lotus root, node of root (NR), leaf, pod of seed (PS), seed (S), and embryo of seed (ES), respectively. Anti-thrombosis activities were evaluated. NR, S, and PS extracts displayed strong anti-coagulation activities, as evidenced by the inhibition of thrombin, prothrombin, and coagulation factors, respectively. NR, leaf, S, and PS extracts displayed strong platelet aggregation inhibitory activities. The aggregation inhibition of S and PS extract was comparable to that of aspirin. The extracts of NR, S, and PS did not show hemolysis activity up to 1.0 mg/ml.

• Korean Journal of Veterinary Research
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• v.31 no.4
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• pp.523-527
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• 1991

The effects of ethylene glycol, DMSO and glycerol as cryoprotectants and the effect of concentrations(0, 0.25, 0.5 and 1.0M) of sucrose in the diluent on the viability of the aggregated morulae frozen rapidly in liquid nitrogen$(LN_2)$ vapour were examined. The morulae were produced by aggregation of ICR and CBA mice embryos at 8-cell stage. Before freezing the embryos were equilibrated in 1.5M cryoprotectants+0.25M sucrose in oae-step or in 3.0M cryoprotectants+0.25M sucrose in two-steps. The embryos were pipetted into the freezing medium fraction of 0.25ml plastic straws. The straws were frozeu by directly transfer into $LN_2$ vapour(about lcm above $LN_2$) for 2 minutes, and then plunged into $LN_2$. After thawing the cryoprotectants were diluted with 0, 0.25, 0.5 or 1.0M sucrose solution. The post-thawed in vitro viability of the aggregated embryos was significantly dependent on the type and concentration of cryoprotectants in the freezing medium and also on the concentration of sucrose in the diluent. When the aggregated embryos were equilibrated in 1.5M cryoprotectants +0.25M sucrose in one-step and diluted with 0.5M sucrose after thawing, the survival rate of the embryo5 was significantly(p<0.05) higher in DMSO(62.5%) or ethylene glycol(52.2%) than in glycerol(33.3 %). In the case that the concentration of the cryoprotectants was raised to 3.0M in two-steps, thc higher survival rate of the embryos was obtained in ethylene glycol or glycerol than in DMSO followed by diluting them with 0.5 or 1.0M sucrose after thawing(p<0.01).

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.4
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• pp.455-461
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• 2001

The effect of exogenous gonadotrophins on superovulation in rabbits was examined. One hundred and sixteen sexually mature California, Chinchilla and New Zealand White rabbits were randomly allocated to control (100 IU hCG), PMSG-treated (100 IU HCG following 150 IU PMSG) and FSH-treated groups (0.3 mg/head /12 h for 3 days followed by 100 IU hCG). All does were mated after hCG injection and were sacrificed or laparotomized within 1 to 4 days postcoitus for counting the number of ovulation points. The number of ovulations was higher in FSH-treated animals than in the control and PMSG-treated groups (37.2 vs. 10.4 and 14.5, p<0.05). Follicle haemorrhagicum was observed in many cases in the PMSG-treated group. No significant difference in ovulation number was observed between left and right ovaries regardless of gonadotropin treatment. In another experiment, 2-cell stage embryos were collected at 26 h postmating and blastomeres were separated by mechanical pipetting or gentle pressure with a fine glass needle. Aggregated or chimeric embryos were produced from two single blastomeres from two breeds, New Zealand White and Chinchlla, with different coat colors. All the embryos were cultured in Ham's F-10 medium supplemented with 1.5% BSA (bovine serum albumin fraction V) and 10% PRS (pregnant rabbit serum), and incubated in a humidified atmosphere with 5% $CO_2$ at $38^{\circ}C$. After development to morula or early blastocyst, the embryos were transferred into the oviducts of recipient does. Results showed that 7 out of 10 does (70%) receiving intact embryos (control) became pregnant and 41 kits were delivered. However, no pregnancy was obtained from the recipient of either denuded demi- or aggregated embryos. It is suggested that embryos without zona pellucida could not develop to term in rabbits.