• Korean Journal of Clinical Laboratory Science
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• v.51 no.3
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• pp.360-369
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• 2019

Cadherins are essential transmembrane proteins that promote cell-cell adhesion and maintain the corpus luteum structure in the ovary. This study examined the influence of prostaglandin F2 alpha ($PGF2{\alpha}$) on E-cadherin, N-cadherin, and adhesion in luteal theca cells (LTCs). The luteal cells were isolated from the mid-phase corpus luteum, and the LTCs were cultured separately from the luteal heterogeneous cells according to the morphology of the mesenchymal cells and to determine if steroidogenic and endothelial cells of LTCs, 3beta-hydroxysteroid dehydrogenase ($3{\beta}$-HSD), and vascular endothelial growth factor receptor 2 (VEGFR2) mRNA were used. The LTCs were then incubated in the culture medium supplemented with 0.01, 0.1, and 1.0 mM $PGF2{\alpha}$ for 24 h, and the E-cadherin and N-cadherin proteins in the LTCs were detected by confocal laser scanning microscopy. The results revealed $3{\beta}$-HSD mRNA expression in the LTC but no VEGF2R mRNA expression. The E-cadherin and N-cadherin proteins of the LTCs were damaged in the 0.01, 0.1, and 1.0 mM $PGF2{\alpha}$ treatment groups, and the expression of the N-cadherin protein was reduced significantly in 0.01 mM $PGF2{\alpha}$ compared to the 0 mM $PGF2{\alpha}$ treatment groups (P<0.05). In addition, the number of attached LTCs were significantly lower in the 0.01 mM $PGF2{\alpha}$ treatment group than in the 0 mM $PGF2{\alpha}$ treatment group (P<0.05). In conclusion, $PGF2{\alpha}$ affected the disruption of cadherin proteins and cell adhesion in LTCs. These results may help better understand the cadherin and adhesion mechanism during corpus luteum regression in the ovary.

• Korean Journal of Poultry Science
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• v.50 no.1
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• pp.41-50
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• 2023

Over the last decade, avian influenza (AI) has been considered an emerging disease that would become the next pandemic, particularly in countries like South Korea, with continuous animal outbreaks. In this situation, risk assessment is highly needed to prevent and prepare for human infection with AI. Thus, we developed the risk assessment matrix for a high-risk area of human infection with AI in South Korea based on the notion that risk is the multiplication of hazards with vulnerability. This matrix consisted of highly pathogenic avian influenza (HPAI) in poultry farms and the number of poultry-associated production facilities assumed as hazards of avian influenza and vulnerability, respectively. The average number of HPAI in poultry farms at the 229-municipal level as the hazard axis of the matrix was predicted using a negative binomial regression with nationwide outbreaks data from 2003 to 2018. The two components of the matrix were classified into five groups using the K-means clustering algorithm and multiplied, consequently producing the area-specific risk level of human infection. As a result, Naju-si, Jeongeup-si, and Namwon-si were categorized as high-risk areas for human infection with AI. These findings would contribute to designing the policies for human infection to minimize socio-economic damages.

• Journal of Marine Life Science
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• v.8 no.2
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• pp.136-149
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• 2023

Basic bioactivities (antioxidant, anti-inflammatory, antibacterial, anticancer, antiviral) were investigated from 370 strains of marine bacteria, fungi, and microalgae obtained from various marine environmental regions in Korea, and the activity results were obtained at the collection site, isolation source, and species level was compared. In the case of marine bacteria, strains belonging to the generally useful genera Streptomyces and Bacillus were observed to have particularly strong efficacy and useful resources were mainly isolated from marine sediments. In the case of marine fungi and microalgae, results showing strong species-specific activity were confirmed, and results showing efficacy-specific activity were also obtained. Based on these results, it is a research result that can facilitate priority access as a strategic material for industrial revitalization and the establishment of a strategy to secure resources based on usefulness when conducting research on chemicals that are selectively effective against specific diseases or when conducting resource-based research. In addition, we believe that by using these results as material for sale through the Marine BioBank (MBB), academia and industry can use them to help accelerate the revitalization of the marine bio industry.

• Journal of Embryo Transfer
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• v.26 no.1
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• pp.19-25
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• 2011

This study was carried out to evaluate the effect of early pregnant cow as donor for Ovum Pick-Up (OPU) derived oocyte aspiration and embryo production in Holstein heifers. Four non-pregnant and 2 pregnant Holstein heifers were used as donor and then carried out total 17 OPU session for 10 weeks (2 times per week). Recovered cumulus-oocyte-complexes (COCs) were classified into 4 grade by oocyte cytoplasm and cumulus cells and matured in vitro in TCM-199 supplemented with 10% FBS, 10 mg/ml FSH and 1 mg/ml estradiol in 5% $CO_2$ and over 99% humidity for 24 h. After 24 h co-incubation with post-thaw sperm, the presumed zygotes were cultured in CR1aa medium with 4 mg/ml BSA for 3 days and then changed CR1aa medium with 10% of FBS for another 3~4 days. The Mean number of aspirated follicles and collected oocytes in the early stage pregnant and non-pregnant heifers were $13.0{\pm}4.3$ and $10.6{\pm}3.9$, $5.4{\pm}3.4$ and $7.7{\pm}3.6$ per session, respectively. Rate of collected oocyte from aspirated follicles were 59.2% and 50.5%, respectively. The average number of good quality oocytes (Grade I and II) in the early stage pregnant and non-pregnant heifers was $3.7{\pm}2.7$ and $4.9{\pm}2.6$ (Mean${\pm}$SD). Cleavage and blastocyst developmental rates in Grade I and II were 22.2% and 25.5%, and then $1.7{\pm}0.9$ and $1.4{\pm}1.1$ blastocyst per session, respectively. In conclusion, OPU technology can be used in early stage pregnant and non-pregnant heifers without any problem and so applied OPU derived embryo production to maximize the ability of genetically valuable females.

• Korean Journal of Agricultural Science
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• v.16 no.2
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• pp.169-178
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• 1989

The study was carried out to elucidate the feedback mechanism on the hypothalamo-hypophyseal system from the functional changes of ovary in female rats. One hundred and forty-four mature female rats were lloted into the three groups; ovariectoimzed group, estradiol treated group and intact control group. The varies of 48 heads of rat were completely removed. Forty eight heads of rat were administered with $200{\mu}g$ of estradiol benzoate every 48 hours. Serum FSH, LH and prolactin levels were determined with radioimmunoassay method at 3,6,12,24 ours, and 5,10, and 15days after treatment. The rats were necropsied to measure the weights of hypophysis and to examin the histological changes in the organs. The results obtained were as follows: The weights of hypophysis were increased after ovariectomy and decreased after estradiol injection. The differences in hypophysis weights were significant between the group from 5 days after treatment. The histological changes in hypophysis were appeared from 5th day after ovariectomy. Proliferation and hypertrophy began to occur in basophilic from 10th day after ovariectomy, chromophobes were slightly hypertrophied and acidophilic cells were atrophied. In estradiol injected rats the histological findings were appeard to be contrary to those of ovariectomized rats. Serum FSH levels significantly changed after ovariectomy and estradiol injection and were higher in both the treated groups than in the intact control group. Within 18 hours after treatment the level was the highest in ovariectomized group, and thereafter the highest level was found in estradiol treated gorup. In ovariectomized rats the levels were rapidly increased 3 hours after treatment and maximum levels were found 18 hours after treatment. In estradiol treated rats the levels started to increase 18 hours after treatment and reached maximum levels 24 hours treatment. 4. Serum LH levels started to increase 3 hours after ovariectomy and estradiol injection and reached maximum levels 12 hours after ovariectomy and 24 hours after estradiol injection. There were significant differences in LH levels between the groups in each observation time. Up to 18 hours after treatment levels were higher in ovariectomized rats than in estradiol treated rats. but thereafter the levels were higher in estradiol treated rats than in ovariectomized rats. The multiple range test showed that a significant difference in LH levels was not found between ovariectomized group and estradiol treated group 18 hours and 5 days after treatment. 5. Serum prolactin levels were significantly changed after ovariectomy and estradiol injection. The levels were lower in ovariectomized rats than in intact control rats.

• Korean Journal of Agricultural Science
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• v.17 no.1
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• pp.34-44
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• 1990

The study was carried out to elucidate the effects of ovarian function on the thyroid gland, adrenal gland and uterus in female rats. One hundred and forty-four mature female rats were allotted into the three groups ; ovariectomized group, estradiol treated group and intact control group. The ovaries of 48 heads of rats were completely removed. Forty eight heads of rats were administered with $200{\mu}g$ of estradiol benzoate every 48 hours. Serum estradiol-$17{\beta}$ and progesterone levels were determined with radioimmunoassay method at 3, 6, 12, 24 hours and 5, 10, 15 days after treatment. The rats were necropsied to measure weights of thyroid gland, adrenal gland and uterus and to examine the histological changes in the organs. The results obtained were as follows ; 1. Serum estradiol-$17{\beta}$ levels were rapidly decreased below 27.20pg/ml 18 hours after ovariectomy. In estradiol treated rats the levels were rapidly increased 18 hours after treatment, but thereafter slowly decreased. The significant differences in the estradiol level were found between the group at every observation time. 2. Serum progesterone levels were significantly decreased after ovariectomy and estradiol injection. The lowest level was found in the group of ovariectomized rats. 3. The weights of thyroid glands decreased in ovariectomized rats rather than in intact rats 5 days after treatment. The weights tended to increase after estradiol injection but significant differences between the groups were seen on 10th and 15th days. 4. In the histological findings of thyroid glands, follicular epithelial cells were changed to be squamous 5 days after ovariectomy and accompanied pyknosis 10 days and karyorrhexis 15 days after ovariectomy. On the contrary follicular epithelial cells were changed to be columnar with hypertrophy 10 days after estradiol injection. 5. The significant differences in adrenal gland weights were recognized between all the groups 5 and 15 days after treatment in ovariectomized rats were lighter than intact rats and the adrenal gland weights were rather heavier in estradiol treated rats. 6. The days after ovariectomy the adrenal glands were atrophied accompanying with pyknosis in the cortical cells of zona fasciculata. The cells in zona fasciculata and zona reticularis started to hypertrophy 5 days after estradiol injection, but no changes were found in the zona glomerulosa of adrenal cortex and in the adrenal medulla. 7. The significant differences in uterus weights were recognized between the groups at each observation time. After ovariectomy the uterus weights decreased rapidly but after estradiol injection they increased rapidly. 8. Through histological examination of uterus, the atrophy and degeneration started to occur in endometrium and lamina propria 12 hours after ovariectomy, and in myometrium one day after ovariectomy, and the changes progressed rapidly after that. On the contrary, the myometrium was proliferated and hypertrophied from 12 hours after estradiol-$17{\beta}$ injection.

• Korean Journal of Poultry Science
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• v.7 no.2
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• pp.54-76
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• 1980

A survey was conducted to determine the status of health and productivity of poultry farms in Korea. Area included Was Kyunggido where exist nearly 50% of national poultry population. From this area, 41 layer and 34 broiler farms covering 21 Countries were selected randomly for the survey. When farms were divided in the operation size, 95.1% of layer and 82.3% of broiler farms were classified as business or industrial level while the rest were managed in a small scale as part time job. Generally layer farms had been established much earlier than broiler farms. Geographically 10.7% of layer farms were sited near the housing area such as field foreast and rice field. No farms were located near the seashore. The distance from one farm from the other was very close, being 80% of the farms within the distance of 1km and as many as 28% of the farms within loom. This concentrated poultry farming in a certain area created serious problems for the sanitation and preventive measures, especially in case of outbreak of infectious diseases. Average farm size was 5,016${\times}$3.3㎡ for layers and 1,037${\times}$3.3㎡ for broilers. 89.5% of layer ana 70.6% of broiler farms owned the land for farming while the rest were on lease. In 60% of layer farms welters were employed for farming while in the rest their own labour was used. Majority of farms were equipped poorly for taking necessary practice of hygiene and sanitation. The amount of disinfectant used by farms was considerably low. As many as 97.6% of lave. farms were practised with Newcastle(ND) and fowl pox(F$.$pox) vaccine, whereas only 43.6% and 5.1% of broiler farms were practised with ND and F$.$pox vaccine, respectively. In 17-32.7% of farms ND vaccine was used less than twice until 60 days of age and in only 14.6% of farms adult birds were vaccinated every 4months. Monthly expense for preventive measures was over 200,000W in 32% of farms. Only 4.9-2.7% of vaccine users were soaking advice from veterinarians before practising vaccination, 85% of the users trusted the efficacy of the vaccines. Selection of medicine was generally determined by the farm owner rather than by veterinarans on whom 33.3% of farms were dependant. When diseases outbroke, 49.3% of farms called for veterinary hospital and the rest were handled by their own veterinarians, salesmen or professionals. Approximately 70% of farms were satisfied with the diagnosis made by the veterinarians. Frequency of disease outbreaks varied according to the age and type of birds. The livabilities of layers during the period of brooding, rearing ana adultwere 90.5, 98.9 and 75.2%, respectively while the livalibility of broilers until marketing was 92.2%. In layers, average culling age, was 533.3 day and hen housed eggs were 232.7. Average feed conversion rates of layers and broilers were 3.30 and 2.48, respectively. Those figures were considerably higher than anticipated but still far lower than those in developed countries.