• Korean Journal of Animal Reproduction
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• v.16 no.1
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• pp.63-76
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• 1992

This study was carried out to investigate the appearance time of the second polar body for producing Gynogenesis or Triploid which could be obtained by arresting the second polar body by cold shock, and then blastoderm was used to measure fertility that revealed the nature of oogenesis, the effects of water temperature on fertility, hatchability, abnormality, viability and growth rate, and the water temperature and the breeding methods to prevent early death of larvae in Korean loach(Misgurnus anguillicaudatus) ; the results obtained in this study were summarized as follows. The second polar body was observed ont he surface of plasma disc close to micropyle within 10~40 min after fertilization at 29$^{\circ}C$. Artificial inseminatin had to be done immediately after the egg spawning because the spermatozoa of loach their mobility within 2 minutes when they were exposed to water. The amount of time needed to reach at blastoderm stage was 12 hours if fertilized eggs were incubated at 16$^{\circ}C$, 8 hours at 19$^{\circ}C$, 6 hours at 21$^{\circ}C$, 5 hours at 23$^{\circ}C$, 4 hours at 26$^{\circ}C$ and 3 hours 30 min at 29$^{\circ}C$ showing the shorter time for development of eggs at higher temperature. Fertilization rates in water temperatures of 19$^{\circ}C$, 21$^{\circ}C$, 23$^{\circ}C$, and 26$^{\circ}C$ were higher than those of water temperatures, 16$^{\circ}C$ and 29$^{\circ}C$. Water temperatures at 19$^{\circ}C$, 21$^{\circ}C$, and 23$^{\circ}C$ showed higher hatching rates that those of 16$^{\circ}C$, 26$^{\circ}C$, and 29$^{\circ}C$, while abnormal rates in 16$^{\circ}C$, 19$^{\circ}C$, 21$^{\circ}C$ and 23$^{\circ}C$ were lower than that of 26$^{\circ}C$ and 29$^{\circ}C$. Water temperatures at 16$^{\circ}C$, 19$^{\circ}C$, 21$^{\circ}C$, 23$^{\circ}C$ and 26$^{\circ}C$ respectively, were more different than 29$^{\circ}C$ in survival rates. The embryos were hatched at 72 hours after fertilization in 16$^{\circ}C$ water temperature, 48 hours in 19$^{\circ}C$, 40 hours in 21$^{\circ}C$, 32 hours in 23$^{\circ}C$, 25 hours in 26$^{\circ}C$, and 16 hours in 29$^{\circ}C$. Within three days after hatched out, the larvage grew 3mm in total length, the yolk granules were entirely consumed and the head and the trunk became thicker. Within 45 days after hatched out, the larva grew 25mm at 29$^{\circ}C$, 21mm at 26$^{\circ}C$, 16mm at 23$^{\circ}C$, 15mm at 21$^{\circ}C$, 12mm at 16$^{\circ}C$ in a 30 litreglass aquarium.

• Korean Journal of Veterinary Research
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• v.35 no.1
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• pp.187-195
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• 1995

The present study carried out to determine the developmental capacity of bovine oocytes matured in epidermal growth factor(EGF)-containing medium, the developmental competence of bovine embryos using synthetic oviduct fluid(SOF) and the effect of glucose on the development of bovine embryos. In experiment 1, oocytes, obtained from abattoir ovaries, were matured in EGF-containing medium for 24 hours, followed by exposure to Korean native cattle spermatozoa for 18 hours and cultured by utilizing co-culture system with bovine oviduct epithelial cells(BOEC) in TCM199. In experiment 2, early bovine embryos were cultured in SOF with or without BOEC and compared with those in TCM199 with BOEC. In experiment 3, bovine embryos were cultured in the presence or absence of glucose. Seven and ten days after in vitro fertilization, developmental competence of embryos were evaluated. The rate of cleavage was significantly(P<0.05) higher in EGF-containing maturation medium(70.0%) than in control(57.7%). The rates of development to morulae and blastocysts were 30.6% and 23.3% there was no significant difference between them. The rates of in vitro fertilized embryos to morulae and blastocysts cultured in SOF with BOEC(30.4%) and in TCM199 with BOEC(38.0%) were significantly(P<0.01) higher than cultured in SOF without BOEC(13.4%) at seven days after in vitro fertilization. The rates of embryos to blastocysts cultured in SOF with BOEC(29.4%) and in TCM199 with BOEC(35.9%) were significantly(P<0.05) higher than cultured in SOF without BOEC(13.4%) at ten days after in vitro fertilization. The rates of early embryos to morulae and blastocysts cultured in the presence or absence of glucose were 12.2% and 17.5% each other, there was no significant difference between them. The results show that bovine oocytes matured in the presence of EGF can cleave better, SOF with BOEC can replace serum containing complex media, TCM199 with BOEC in bovine embryo culture and glucose have little effect on the culture of early bovine embryos.

• Clinical and Experimental Reproductive Medicine
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• v.22 no.2
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• pp.211-220
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• 1995

Though the endometriosis is not always related with infertility, endometriosis causes infertility in some patients. There are many treatment modalities of infertile patients who have endometriosis. In recent years, Assisted Reproductive Technology(ART) have been widely accepted as being a useful tool for the treatment of infertile endometriotic patients. The objective of this study was to evaluate the outcome of ART in infertile endometriotic patients who have been carried out IVF-ET from Jan, 1992 to Dec, 1994 and to compare the results between COH/IUI and IVF-ET in the patients with endometriosis stage I. Tubal disease only patients were grouped(308 patient, 956 cycles) as a control. Endometriosis group was subdivided into 4 groups according to American Fertility Society classification; endometriosis stage I (45 patients, 61 cycles), stage II (26 patients, 39 cycles), stage III (26 pateitns, 37 cycles), stage IV (33 patients, 50 cycles). The outcomes of IVF-ET in endometriosis patients were as follows; The oocyte recovery rates were significantly lower in stage III, IV endometriosis. In case of stage III endometriosis, the fertilization rate was significantly lower than other stages of endometriosis. Clinical pregnancy rates per cycle were not different between the tubal group(22%) and the endometriosis group(25%). According to endometriosis stage, the implantation rate and clinical pregnancy rate were significantly lower in stage IV (5.6%, 16%) compared with other stages (I; 10.0%, 26%, II;9.8%, 31%, III;12.6%, 32%). It suggests that some factor like autoantibodies may inhibit implantation of embryos in stage IV endometriosis. To evaluate the possibility that simply increasing the number of gametes at the site of fertilization might account for pregnancies attributed to IVF-ET, the authors retrospectively analyzed the outcome of couples undergoing IUI during hMG cycles and CC cycles between 1992 and 1994 in the women with endometriosis stage 1. In case of stage I endometriosis, though the COH/IUI group showed lower FSH level and lesser age profile than IVF-ET group, IUI group has resulted in lower pregnancy rates(19.2%) compared with the IVF-ET group(26.2%). In conclusion, endometriotic infertile patients can get comparable pregnancy rates with the tubal factor infertility patients during IVF-ET program. Moreover even in stage I endometriosis, IVF-ET may be an more effective treatment modality than COH/IUI.

• Journal of Ecology and Environment
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• v.35 no.4
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• pp.307-311
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• 2012

This study was conducted to evaluate the dynamics of soil respiration (total soil and heterotrophic respiration) following fertilizer application in red pine forests. Fertilizer (N:P:K = 113:150:37 kg/ha), which reflects current practices in Korean forest, was applied in April 2011, and total soil and heterotrophic respiration rates were monitored from April 2011 to March 2012. Monthly variation of total soil and heterotrophic respiration rates were similar between the fertilizer and control treatments, as soil temperature was the dominant factor controlling the both rates. Total soil respiration rates during the study period were not significantly different between the fertilizer (0.504 g $CO_2\;m^{-2}\;h^{-1}$) and control (0.501 g $CO_2\;m^{-2}\;h^{-1}$) treatments. However, the proportion of heterotrophic respiration was higher in the fertilizer (78% of total soil respiration rates) than in the control (62% of total soil respiration rates) treatments. These results suggest that current fertilizer practices in Korea forest soil do not substantially affect total soil respiration rates.

• Korean Journal of Agricultural and Forest Meteorology
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• v.3 no.4
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• pp.177-184
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• 2001

This study was conducted to identify the optimum nitrogen (N) fertilization at panicle initiation stage on ridge direct seeding on dry paddy of rice. During 1999~2000, a series of experiments was carried out at field (Chonbuk series) of the National Honam Agricultural Experiment Station, RDA using Dongjinbyeo. Plants were taller, and leaf area index and top dry weight increased with more N fertilization at panicle initiation stage. Photosynthetic rate of heading stage was higher at higher amounts of N fertilization at panicle initiation stage, especially in 6 kg/10a compared with 10 kg/10a seeding rate. Lodging index and its related traits did not significantly differ under different rates of N fertilization at panicle initiation stage. N uptake of the rice plant increased as more N fertilization at panicle initiation stage. N use efficiency was highest under the standard topdressing rate at 6 kg/10a seeding rate. Panicle number per m$^2$ increased with more topdressed N, but ripened grain rate and 1,000-grain weight of brown rice did not differ with an increase in topdressed N. Milled rice yield was 6% higher in the 6 kg/10a seeding rate and 13% higher in the 10 kg/10a seeding rate at 50% more topdressed N compared with 4.8 kg/10a N fertilization at panicle initiation stage of 6 kg/10a seeding rate.

• Journal of Embryo Transfer
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• v.30 no.4
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• pp.283-287
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• 2015

The aim of the present study was to investigate the ovulation rate and its relationship to fertilization ability in Landrace, Durock and Crossbred pigs. Gilts were natural mated at a body weight of at least 120 kg under the same hormone treatment. Embryos were surgically collected 1 day after natural mating (Day 0). Embryos derived from in vivo-fertilized oocytes were cultured in medium PZM-3. The ovaries were examined and the pathological findings were recorded. The number of corpus hemorrhagicum was counted, and was assumed to equal the ovulation rate. There was no difference in the number of corpus hemorrhagicum (20.4, 28.8 and 23.2) and ovulation (13.5, 26.8 and 17.2) in the Landrace, Durock and Crossbred pigs. The two pronucleus formation was 76.0, 80.0 and 86.9%. The Day-7 embryos had blastocyst rates of 68.0, 75.0 and 73.9%. There was no difference in the number of total cells and apoptotic cells. In the future, more studies require determining relationships between ovulation and fertilization rate in different species of pigs.

• Clinical and Experimental Reproductive Medicine
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• v.42 no.3
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• pp.77-85
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• 2015

One of the key factors of early development is the specification of competence between the oocyte and the sperm, which occurs during gametogenesis. However, the starting point, growth, and maturation for acquiring competence during spermatogenesis and oogenesis in mammals are very different. Spermatogenesis includes spermiogenesis, but such a metamorphosis is not observed during oogenesis. Glycosylation, a ubiquitous modification, is a preliminary requisite for distribution of the structural and functional components of spermatids for metamorphosis. In addition, glycosylation using epididymal or female genital secretory glycans is an important process for the sperm maturation, the acquisition of the potential for fertilization, and the acceleration of early embryo development. However, nonemzymatic unexpected covalent bonding of a carbohydrate and malglycosylation can result in falling fertility rates as shown in the diabetic male. So far, glycosylation during spermatogenesis and the dynamics of the plasma membrane in the process of capacitation and fertilization have been evaluated, and a powerful role of glycosylation in spermatogenesis and early development is also suggested by structural bioinformatics, functional genomics, and functional proteomics. Further understanding of glycosylation is needed to provide a better understanding of fertilization and embryo development and for the development of new diagnostic and therapeutic tools for infertility.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.32 no.3
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• pp.347-352
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• 1987

This studies were carried out to investigate the effects of nitrogen fertilizer rates and methods of its application on maturity of leaves, total nitrogen and total alkaloids concentration in burley tobacco leaves. Nitrogen rate ranged from 17.5 to 40.5kg/10a and applied through basic fertilization and sidedressing. The filling capacity of cured leaves was decreased with increasing levels of nitrogen fertilizer. As the rate of nitrogen fertilization was increased or sidedressing, the maturity of leaves was delayed and total alkaloids and total nitrogen concentration were increased. Total alkaloids concentration in leaves was gradually increased, especially more in upper leaves from 60 to no days after tratnsplanting, but total nitrogen concentration was decreased.

• Korean Journal of Animal Reproduction
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• v.14 no.3
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• pp.223-230
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• 1990

This experiment was carried out to investigate in vitro maturation rate of pig follicular oocytes cultured from 30 to 48hr in TCM 199 supplemented with gonadotropins(FSH, LH) and estradiol-17$\beta$ and in vitro fertilization with ejaculated sperm preincubated in BO medium containing 2mM caffein and development of IVF oocytes. The results obtained in this experiments were as follows ; 1. In addition of hormones, in vitro maturation rate of follicular oocyte increased gradually from 36hr and 74.47% at 48hr in addition of hormones, but there was no differences among in vitro maturation rates after 36hr of culture. 2. Penetration rate of pig oocytes matured in FSH＋LH＋E2 and FSH＋E2 was 71.8%, 71.0% and significantly increased by the addition of hormones. 3. Percentage of developed oocytes was 44.4% for oocytes matured in FSH＋LH＋E2-added medium and 48.7% for oocytes matured in FSH＋E2-added medium, respectively. 4. Two to 16 cells stage embryos were obtained only when pig oocytes matuerd in vitro in hormones-added medium and 72hr after IVF. 5. From present results, it is concluded that gonadotropins and estradiol17$\beta$ can enhance in vitro fertilization and subsequent development as well as in vitro maturation pig follicular oocytes.

• Korean Journal of Animal Reproduction
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• v.22 no.1
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• pp.43-50
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• 1998

The effect of oxygen tension on embryonic development in co-culture was evaluated from the standpoint of the reduction of dissolved oxygen concentration by the oxygen consumption of feeder cells. Three co-culture systems using bovine oviductal epitherial cells (BOEC), African green monkey kidney cells (Vero cells) or buffalo rat liver cells (BRLC) have been compared in terms of development of bovine embryos derived from oocytes matured and fertilized in vitro. Among the co-cultured embryo, Vero cells su, pp.rted the highest developmental rate (29%) and the other two showed the similar rates. When the co-cultures were incubated in three different oxygen tension such as 5, 10, 20% oxygen atmosphere, embryos co-cultured with Vero cells at 10%-O2 resulted in the highest percentage of development. From the measurement of oxygen consumption of feeder cells, BRLC consumed 1.38　10-10 mg-O2/min/cell which was higher than 0.94　10-10 and 0.26　10-10mg-O2/min/cell for Vero cells and BOEC, respectively. Based on the oxygen consumption data, the phenomena of optimum oxygen tension required in embryo development in vitro has been analyzed, and we suggested that gas phase oxygen concentration, oxygen consumption rate of feeder cells and the number of feeder cells should be considered for the design of optimal co-culture system for effective fertilization of embryos in vitro.