• Journal of fish pathology
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• v.23 no.1
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• pp.113-118
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• 2010

The present work describes myxozoan parasite found in the skin of cultured snakehead, Channa argus fingerings (total length, 5.5~7.2 cm) from Busan, Korea. Nature spores and plasmodia were found in the skin mucus of infected fishes. In fresh state, the total length of the spore was $27.96{\pm}2.50{\mu}m$. The size of spore body was $14.16{\pm}1.78{\mu}m{\times}4.88{\pm}0.61{\mu}m$. The polar capsules were pyriform and the size was $5.57{\pm}0.66{\mu}m{\times}1.36{\pm}0.33{\mu}m$. This is the first report of Henneguya sp. from cultured fish species in Korea, and further studies are necessary for definitive identification.

• Reproductive and Developmental Biology
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• v.39 no.2
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• pp.29-36
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• 2015

Pigs are considered an ideal source of human disease model due to their physiological similarities to humans. However, the low efficiency of in vitro embryo production (IVP) is still a major barrier in the production of pig offspring with gene manipulation. Despite ongoing advances in the associated technologies, the developmental capacity of IVP pig embryos is still lower than that of their in vivo counterparts, as well as IVP embryos of other species (e.g., cattle and mice). The efficiency of IVP can be influenced by many factors that affect various critical steps in the process. The previous relevant reviews have focused on the in vitro maturation system, in vitro culture conditions, in vitro fertilization medium, issues with polyspermy, the utilized technologies, etc. In this review, we concentrate on factors that have not been fully detailed in prior reviews, such as the oocyte morphology, oocyte recovery methods, denuding procedures, first polar body morphology and embryo quality.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.8
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• pp.1076-1079
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• 2004

Antibiotics are common additives in culture media during in vitro embryo development, but their effects on oocyte maturation in vitro have not been tested. The effects of penicillin, streptomycin and gentamicin on the maturational competence and subsequent development potential of goat follicular oocytes were examined after parthenogenetic activation in vitro. Maturation rates at 24 h after in vitro maturation, and parthenogenetic development at 48 h after activation, were evaluated by observing the protruding first polar body and the 4 cell stage cleavage, respectively. When streptomycin was present in the maturation medium, the percentages of matured oocytes 24 h after activation were significantly (p<0.01) lower than those from the other groups (42.5-45.7% vs. 69.1-73.8%). Penicillin and gentamicin treatment did not affect the maturation rates or the percentages reaching the 4 cell stage 48 h after activation. There was no significant difference in cleavage rates among the different antibiotic treatments 48 h after activation. Therefore, streptomycin suppresses the in vitro maturation of immature goat oocytes, but does not influence their subsequent development.

• Korean Journal of Animal Reproduction
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• v.22 no.3
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• pp.265-276
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• 1998

In an attempt to evaluate the function of MAP kinase of porcine oocytes and to develop a method of assessment for kinase activity, we used MBP as a substrate to detect the MAP kinase activity of porcine oocytes matured in in vitro. The MAP kinase which had lower activity during the first 20 hours of culture started to show an increased amount of activity at 25 hours at which a collapse in nuclear membrane was induced. Significant (P<0.05) a, pp.ared at 30 hours of being cultured. The gel phosphorylation method, MBP which has been known to be a substrate for kinase such as cdc2 kinase, was phosphorylated at two positions corresponding to ERK 1 (44kDa) and ERK2 (42 kDa) which are known as mammalian MAP kinase. The existence of MARKK and MAP kinase were identified with western blotting at 0 hour culture of immature GV oocytes. The amount of those proteins did not increase during 40 hours of culture, which suggest that the increase of MAP kinase activity was caused by phosphorylaton rather than due to change in protein amount. MAPKK and MAP kinase were shown to be dephosporylated with deactivated at M 1 stage by inhibition of protein synthesis with cycloheximide added at the strat following the cultrue. We have reulsts that indicate the existedence of MAP kinase cascade which was activated simultaneously with start of porcine oocyte maturation (GVBD).

• Journal of Embryo Transfer
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• v.19 no.3
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• pp.229-237
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• 2004

The main objective of this study was to examine the effects of serum and gonadotropins supplement during in vitro maturation(IVM) of bovine oocytes on nuclear maturation and embryo development, and we also examine the cell number. 1 . The first polar body(PB) extrusion rates of Korean native cow(KNC) oocytes matured in medium with FBS or gonadotropins were similar among treatment groups. The development rate to the blastocyst stage was significantly higher in the group of both supplement FBS and gonadotropins(26.0％) than in the group of non-supplement(9.9％) and gonadotropins (12.0％). The numbers of inner cell mass (ICM) and trophectoderm (TE) cells and total cell numbers of blastocysts were highest in the group of both supplement FBS and gonadotropins, and the number of ICM cells was increased by FBS supplementation (p<0.05). 2. The PB extrusion rates of KNC oocytes matured in medium with FBS in the different duration of IVM was significantly higher in the 0-18hr(63.1％) and in the 9-18hr(63.4％) group than in the 0-9hr.(37.4％) group (p<0.05). The embryo development rates did not differ among treatment groups. The numbers of TE cells and total cell numbers of blastocysts were similar among treatment groups, but the number of ICM cells of the 0-18h. group were significantly higher than the other treatment groups (p<0.05). The results indicate that although TCM199 alone can support bovine oocyte maturation and development to the blastocyst stage, a high quality of blastocysts can be produced from oocytes matured in medium containing serum and gonadotropins.

• Journal of Aquaculture
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• v.10 no.2
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• pp.123-131
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• 1997

Growth of triploid abalone, Haliotis discus hannai induced by cody (3$^{\circ}C$) shock and its feed efficiency were investigated from larva to adult for 51 months. After 51 months from triploidy induction, the triploid abalones have outgrown to diploid abalones in shell length and total weight. Triploid abalones with inhibition of extrusion of first polar body (3n-1pb) were outgrown to diploid abalones, however, triploid abalones with inhibition of extrusion of second polar body (3n-2pb) were not significantly different from diploid controls in shell length and total weight through the whole rearing period (P<0.05), because of their heterozygosity differences. Daily feeding rates and feed conversion rates decreased with the growth of abalones and both rates had no differnce between two experimental groups. After 51 months from inducing triploid, conditin index of triploid abalone (64.1%) was higher than that of diploid control (59.4%) (P<0.05). Survival rate was 63.0% in triploid group (3n-1pb 62.0%, 3n-2pb 64.0%) and 62.0% in diploid group during the experimental period.

• Journal of Embryo Transfer
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• v.16 no.3
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• pp.223-231
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• 2001

The success of nuclear transplantation with mammalian oocytes depends critically on the potential of oocytes activation, which mainly caused to prevent the re-accumulation of maturation promoting factor (MPF). This study was conducted to compare the effect of combined treatment of lonomycin with a Hl-histone kinase inhibitor (dimethylaminopurine, DMAP) or cdc2 kinase inhibitor (sodium pyrophosphate, SPP) on activation of bovine oocytes. In vitro matured bovine oocytes with the first polar body (PB) and dense cytoplasm were assigned to 3 experimental groups. For activation treatment, oocytcs were exposed to 5 $\mu$M lonomycin for 5 min (Group 1), and followed by 1.9 mM dimethylaminopurine (DMAP) for 3 h (Group 2) or followed by 2 mM sodium pyrophosphate (SPP) for 3 h (Group 3). The activation effects in the three treatments and the control group (untreated) were judged by the extrusion of the second PB and formation of a pronucleus (PN). Differences among groups were analysed using one-way ANOVA after arc-sine transformation of proportional data. All three treatments led to high activation rates (90% to 95%), with significant difference from the control. However, the extrusion of the second PB and the rate of PN formation differed remarkably among treatments. In Group I and 3, about 95% of the oocytes had extruded the second polar body, but one PN had formed in a higher proportion of oocytes in Group 3 than in Group 1 (90% vs. 5%). In experiment 2, the rates of cleavage and development into blastocysts in Group 1 were significantly lower than those of Group 2 and 3 (8.7% and 0% vs. 50.5% and 11.6%, and 44.6% and 7.2%, respectively, P<0.05). In experiment 3, ~80% of parthenotes in Group 1 were developed with haploid chromosomal sets. However, when ionomycin was followed immediately by DMAP (Group 2). only 20% of parthenotes were haploid. In Group 3, combined treatment with ionomycin and SPP, the appearance of abnormal chromosomal tracts was significantly (P〈0.05) reduced and the proportion of haploid parthenotes was increased to 85% (17/20) than in Group 2. These results demonstrate that SPP acted as a cdc2 kinase inhibitor and formed the haploidy in oocyte activation. Thus, the present study suggests that cdc2 kinase inhibitor, such as sodium pyrophosphate, may have an effective role in oocyte activation for the production of cloned embryos/animals by nuclear transplantation.

• Journal of Embryo Transfer
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• v.10 no.1
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• pp.73-82
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• 1995

large scale production of cloned embryos requires the technology of multiple generation nuclear transplantation(NT) using NT embryos as the subsequent donor nuclei. The purposes of this study were producing the second generation cloned rabbit embryos, and also to determine the electrofusion rate and in vitro developmental potential comparatively in the cloned embryos of the first and second NT generation. The embryos of 16-cell stage were collected from the mated does by flushing oviducts with Dulbecco's phosphate buffered saline(D-PBS) containing 10% fetal calf serum(FCS) at 47 hours after hCG injection In the first generation NT, the nuclear donor embryos were synchronized in the phase of Gi /S transition of 32-cell stage. The first generation NT embryos which were developed to 8-cell were synchronized in Gi /S transition phase of the following 16-cell stage and used as donor nuclei for second generation Synchronization of the cell cycle of blastomeres was induced, first, using an inhibitor of microtuble polymerization, colcemid for 10 hours to arrest blastomeres in M phase, and secondly, using a DNA synthesis inhibitor, aphidicolin for 1.5 to 2 hours to arrest them in Gi /S transition boundary. The recipient cytoplasms were obtained by removing the nucleus and the first polar body from the oocytes collected at 14 hours after hCG injection. The separated donor blastomeres were injected into the enucleated recipient oocytes by micromanipulation and were electrofused by electrical stimulation of three pulses for 60 $\mu$sec at 1.25 kV /cm in 0.28 M rnannitol solution The fused oocytes were co-cultured with a monolayer of rabbit oviductal epithelial cells in M-199 solution containing 10% FCS for 120 hours at 39$^{\circ}C$ in a 5% $CO_2$ incubator. Following in vitro culture of the first and second generation cloned embryos to blastocyst stage, they were stained with Hoechst 33342 dye for counting the number of blastomeres by fluorescence microscopy. The results obtained were summarized as follows: 1. The electrofusion rate was found to be similar as 79.4 and 91.5% in the first and second generation NT rabbit embryos, respectively. 2. The in vitro developmental potential to blastocyst stage of the second generation NT embryos (23.3%) was found significantly(p<0.05) lower, compared with that of the first generation NT embryos (56.8%). 3. The mean blastomeres counts of embryos developed to blastosyst stage following in vitro culture for 120 hours and also their daily cell cycles during the culture period were decreased significantly (p<0.05) to 104.3 cells and 1.33 cylces in the second NT generation, compoared with 210.4 cells and 1.54 cycles in the first NT generation, respectively.

• Ocean and Polar Research
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• v.32 no.4
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• pp.369-377
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• 2010

To characterize ecotoxicological responses to a natural estrogen, $17{\beta}$-estradiol, we evaluated the life-history of the parental ($F_0$) and first generation ($F_1$) of the harpacticoid copepod, Tigriopus japonicus sensu lato. We evaluated the survival of nauplii and copepodites, the number of days until the emergence of copepodites and adult males, the sex ratio, brooding success, and the first brooding day of adult females. No significant differences in the survival rate were noted in response to treatments with different concentrations of $17{\beta}$-estradiol. However, $17{\beta}$-estradiol induced developmental delay and skewed the sex ratio toward males. Copepod development was delayed significantly in the 0.1 and $1\;{\mu}g\;l^{-1}$ $17{\beta}$-estradiol treatment groups relative to the control group, with a more pronounced delay in the $F_1$ group. Body length and biomass were significantly smaller in the $17{\beta}$-estradiol treated groups than in the controls. The male emergence of T. japonicus s.l. was very high in the 10 and $30\;{\mu}g\;l^{-1}$ $17{\beta}$-estradiol treatment group. Furthermore, exposure to $17{\beta}$-estradiol resulted in morphological deformities such as shrinking and swelling of the urosome, twisted setae of the caudal rami, setal loss of swimming legs, abnormal segmentation of antennules, and dwarfism.

• Journal of Veterinary Clinics
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• v.12 no.1
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• pp.877-886
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• 1995

The recycling nuclear transplantation(NT) technique has the powerful potential of producing a large number of genetically identical embryos and offsprings from one embryo. Multiple generational cloning by this technique utilizes the NT embryo itself as the donor for the next generation of cloning. In this experiment, we have produced the third generational cloned embryos by recycling NT. Further we examined comparatively the electrofusion rate and in vitro developmental potential in the cloned embryos of the first second and third generations. The embryos of 16-cell stage were collected from the mated does by flushing oviducts with Dulberco's phosphate buffered saline containing 10 % fetal calf serum(FCS) at 47 hours after hCG injection. In the first generation NT, the nuclear donor embryos were synchronized in the phase of Gl/S transition of 32-cell stage. The first and second generation NT embryos developed to 16-cell were used as donor nuclei for second and third generation. The recipient cytoplasms were utilized the oocytes collected at 14 hours after hCG injection, following revoming the nucleus and the first polar body by micromanipulation. The separated blastomeres were injected into the enucleated recipient oocytes by micromanipulation and were fused by electrical stimulation. The electrofusion rate was seen to be 78.0, 88.0 and 90.3 % in the first second and third generation NT rabbit embryos, respectively. The fused oocytes were co-cultured with a monolayer of rabbit oviductal epithelial cells in M-199 solution containing 10 % FCS for 120 hours at 39$^{\circ}C$ in a 5% $CO_2$ incubator. The in vitro developmental potential to blastocyst stage was significantly(P<0.05) decreased in the third(7.2 %) generation NT embryos compared to the first(53.1 %) and second(16.1 %) generation NT embryos. Following in vitro development to blastocyst stage, they were stained with Hoechst 33342 dye for counting the number of blastomeres by fluorescence microscopy. The mean blastomere numbers and cell cycle numbers of NT embryos during the culture period were significantly(p<0.05) decreased in the second(93.9 cells and 6.55 cylces) and third(81.5 cells and 1.35 cylces) generation, compared to the first(189.9 cells and 7.55 cylces) generation.