• Proceedings of the KSAR Conference
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• 2000.10a
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• pp.7-8
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• 2000

Transgenic animals are very useful for scientific, pharmaceutical, and agricultural purposes. In livestock, transgenic technology has been used forthe genetic alteration of farm animals, the production of human proteins inlarge quantities in the milk of transgenic farm animals, and the generation of animals with organs suitable for xenotransplantation. To date, the transfer of foreign genes into farm animals has been performed mainly by microinjection of DNA into the pronuclei of fertilized eggs. However, the overall success rate of transgenic animals in livestock so far has been disappointingly low, eg., the efficiency is 0∼5% in swine, and less than 1% in sheep and cattle, compared with the rate in mice where 5% microinjected develop into transgenic animals. Recently, McGreath et al. (2000) have succeeded in producing the gene targeted sheep by the use of nuclear transfer from cultured somatic cells transfected with a foreign gene in vitro. However, we may need plenty of time until currently employ this method for gene transfer to farm animals. We have been studying to exploit the method for improving production efficiencies of transgenic animals with emphasis of its application to farm animals. The present paper describes three approaches that we have made in our laboratory to improve production efficiencies of transgenic animals, based on the DNA microinjection method. 1. Co-injection of restriction enzyme with foreign DNA into the pronucleus for elevating production efficiencies of transgenic animals. 2. Efficient selection of transgenic mouse embryos using EGFP as a marker gene. 3. Phenotypes of tansgenic mice expressing WAP/hGH-CAG/EGFP fusion gene produced by selecting transgenic embryos. 4. Efficient site-specific integration of the transgene targeting an endogenous lox like site in early mouse embryos.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.3
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• pp.223-229
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• 2003

Annual radiation dose of residential individuals near 4 nuclear power plants in Korea was calculated via K-DOSE 60 based on the updated ICRP-60. The critical exposure variables were chosen as radionuclides, exposed organs and intake pathways. From the calculation results, the critical nuclides were found to be $^3$H, $^{133}$ Xe, $^{60}$ Co for Kori plants and $^{14}$ C, $^{41}$ Ar for Wolsung plants. The most critical pathway was 'vegetable intake' for adults and 'milk intake' for infants. However, there was no preference in the effective organs. Sensitivity analyses showed that the chemical composition in a nuclide much more influenced upon the radiation dose than any other input parameters such as food intake, radiation discharge, and transfer/concentration coefficients by more than 10$^2$ factor. The effect of transfer/concentration coefficients on the radiation dose was negligible. All input parameters showed highly estimated correlation with the radiation dose, approxinated to 1.0.

• Korean Journal of Veterinary Research
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• v.20 no.2
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• pp.113-118
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• 1980

Total of 11 strains of Ldctobacillus isolated from lactobacillus-fermented milk and-beverage in March 1980 were examined for susceptibility to 8 drugs, and transferability and transfer frequency of R plasmids by conjugation. Of 11 isolates each 2 strains were classified as L. cellobiosus and L. helveticus, each 1 strain as L. plantarum, L. lactis, L. acidophilus, L. delbrueckii, L. casei subsp. casei, L. casei subsp, tolerans and L. salivarius subsp, salivarius by Bergey's manual. Resistance was the most active to na lidixic acid(NA), followed in decreasing order by chloramphenicol(CP), ampicillin(AP), kanamycin(KM) and streptomycin(SM). All of isolates were resistant to NA, each 10 strains to CP and AP, 7strains to KM and 6 strains to SM, indicating all of the isolates were resistant to two or more drugs in combination. No strain was resistant to erythromycin(EM), penicillin(PC) and tetracycline(TC). The most frequently encountered resistant patterns were CP NA AP SM KM, followed by CP NA AP KM, NA AP, CP NA, CP NA AP and CP NA AP SM in order. Transfer experiment of drug resistance showed that of 11 resistant strains, 9 strains transferred parts of their resistance to AP or AP CP or SM AP, indicating 9 strains carried R plasmids determining R(AP), R(AP CP) and R(SM AP). The conjugal frequency of R(AP) from Lactobacillus to E. coli ranged from 2.5{\times}10^{-1} to $5.6{\times}10^{-4}%$, that of R(CP) ranged from 5.0{\times}10^{-1} to 5.0{\times}10^{-3}% and that of R(SM) ranged from 6.0{\times}10^{-5} to 1.4{\times}10^{-5}%, at $37^{\circ}C$ for 18 hours of incubation.

• Journal of Dairy Science and Biotechnology
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• v.23 no.1
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• pp.49-63
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• 2005

China that holds various and plentiful food resources had little growth in dairy industry compared with her long history. But after the establishment the People's Republic of China, It began to activate. Because of the economic growth and the improvement of living standard of China, dairy products were becoming common food, so Chinese dairy industry was considering as a industry which accomplishes a rapid growth. On the ground of a sudden economic growth, the progress of income level of China and the open economy, the world dairy industry was concerned about the Chinese market, so, the Chinese dairy industry would bring an exorbitant change in the world dairy industry. Therefore, We Korean dairy industry must make inroads into the Chinese market by making a royalty profit through the transfer of technical know-how and the export of dairy products.

• Journal of Animal Reproduction and Biotechnology
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• v.35 no.2
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• pp.119-141
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• 2020

The Dromedary camel (Camelus dromedaries) is an important species because of its ability to produce good quality meat, milk, and fibers under harsh environmental conditions. Camels are also crucial for transportation, racing, and as draft animals in agriculture. Therefore, dromedary camels play a critical role in the economy for millions of people living in the arid part of the world. The inherent capability of camels to produce meat and milk is highly correlated with their reproductive performance. Compared with other domestic species, the reproductive efficiency in camelids is low. Although recent reproductive technologies such as in vitro fertilization (IVF) and somatic cell nuclear transfer (SCNT) have been successfully applied to camelids and the birth of live offspring following these technologies has been reported; in vitro embryo production (IVP) has lagged in this species. The development of the IVP system for dromedary camels may be a useful tool for the genetic improvement of this species. IVP in farm animals includes three main steps; in vitro maturation (IVM) of an oocyte, IVF of a matured oocyte, and in vitro culture (IVC) of fertilized oocyte up to the blastocyst stage. This review aims to summarize various factors that influence oocyte quality, IVM, and in vitro embryo development in dromedary camel.

• Journal of Embryo Transfer
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• v.17 no.3
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• pp.171-177
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• 2002

Glucocorticoid is activating mammary gland cells for lactating animals, resulting in increasing abilities of the milk synthesis. Expression of the prolactin receptor(PRL-R) in mammary gland cells was closely associated with milk production. To increase lactation ability for the Korean Native Goats at mid-lactation period. 0.05, 0.1. and 0.2 g of hydrocortisone was administrated with 5 $m\ell$ of saline. and injected into vein. For the control, 5 $m\ell$ of saline was administrated in to vein. After 24 H, the mammary gland tissue was collected, and mRNA expression rates were investigated for the alpha-casein and PRL-R using competitive PCR(polymerase chain reaction). There was no significant differences between treatment and control groups for the mRNA expression rate of PRL-R in mammary gland cells after 24 h of administration of hydrocortisone. The rate of mRNA expression for the alpha-casein was increased 37%, 630%, and 380% at 0.05, 0.1, and 0.2 g of hydrocortisone administration groups, respectively, comparing with control group. The results suggested that PR L-R mRNA expression of mammary gland cell by administration of hydrocortison was not significant, but increase of the alpha-casein mRNA expression my be differences of expression of functional proteins in the cell and expression patterns of protein secretion time to out of the cell. This study showed increase of alpha-casein mRNA expression by administration of hydrocortisone at mid-lactation period of Korean native goat.

• Korean Journal of Microbiology
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• v.49 no.2
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• pp.126-130
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• 2013

The major aim of this study was to investigate the distribution of genes that encode multidrug efflux pumps in Enterococci spp. isolates from bovine milk samples and antibiotic resistance patterns of these strains. Of the 245 isolates, 44.1% showed ampicillin resistance, 79.2% showed erythromycin resistance, 76.3% showed tetracycline resistance and 36.3% showed chloramphenicol resistance. In case of vancomycin and ciprofloxacin, all of the isolates were susceptible to these antibiotics. Of the 245 enterococcal isolates, 82.1% have MFS type eme(A) gene, 72.7% have ABC type efr(A) gene, 77.1% have ABC type efr(B) gene, and 71.8% have ABC type lsa gene. In case of Enterococcus faecalis, the original strain for these genes, 92.5% have eme(A), 87.4% have efr(A), 88.4% have efr(B), and 88.4% have lsa. Interestingly, in case of different species of Enterococci, eme(A) was also detected in four strains of E. faecium, seven strains of E. avium, four strains of E. durans and two strains of E. raffinosus. efr(A) was also detected in two strains of E. faecium and two strains of E. durans and efr(B) was also detected in four strains of E. faecium, five strains of E. avium and four strains of E. durans. This means the possibility of co-transfer of resistance genes between Enterococci species in natural environment. These results are the first report describing the presence of same multidrug efflux pumps in different species of Enterococci in Korea.

• Food Science of Animal Resources
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• v.31 no.3
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• pp.442-450
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• 2011

We investigated the improvement in intestinal function and the constipation preventive and remedial effects of the fermented milk product R&B $Rhythm^{(R)}$ in mice and rats. The results showed that the effects varied significantly among different doses. The digestive tract transfer rate increased dramatically in a dose-dependent manner in both animals. Compared with treating constipation with loperamide alone, treatment with loperamide and the fermented milk R&B Rhythm improved the number of fecal pellets from the animals, suggesting that it is effective for preventing and relieving constipation. Both the quantity of feces and water content of the feces increased significantly at high levels of yogurt feeding. These results suggest that repetitively ingesting fermented milk products could be effective for preventing and treating constipation symptoms.

• Journal of Radiation Protection and Research
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• v.25 no.4
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• pp.233-239
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• 2000

The sensitivity analysis of input parameters was Performed fer an ingestion dose assessment model (U. S. NRC's Regulatory Guide 1.109 model) from routine releases of radionuclides. In this study, three kinds of typical Korean foodstuffs (rice, leaff vegetables, milk) and two kinds of radionuclides $(^{l37}Cs,\;^{131}I)$ were considered. The values of input parameters were sampled using a Latin hypercube sampling technique based on Monte Carlo approach. Sensitivity indices, which represent the influence or the importance of input parameters for predictive results, were quantitatively expressed by the partial rank correlation coefficients. As the results, the ratio of the interception fraction to the yield of agricultural plants and the human consumption rate were sensitive input parameters for the considered foodstuffs and radionuclides. Additionally, in case of milk, the transfer factor of radionuclides from animal intake to milk and the daily intake rate of feedstuffs were sensitive input parameters. The weathering removal half-life and the delay time from food production to human consumption were relatively sensitive for $^{137}Cs$ and $^{131}I$ depositions, respectively.

• Journal of Radiation Protection and Research
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• v.25 no.1
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• pp.11-19
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• 2000

The sensitivity analysis of input parameters for a dynamic food chain model DYNACON was conducted as a function of deposition date for the long-lived radionuclides $(^{137}Cs,\;^{90}Sr)$. Also, the influence of input parameters for the short and long-terms contamination of selected foodstuffs (cereals, leafy vegetables, milk) was investigated. The input parameters were sampled using the LHS technique, and their sensitivity indices represented as PRCC. The sensitivity index was strongly dependent on contamination period as well as deposition date. In case of deposition during the growing stages of plants, the input parameters associated with contamination by foliar absorption were relatively important in long-term contamination as well as short-term contamination. They were also important in short-term contamination in case of deposition during the non-growing stages. In long-term contamination, the influence of input parameters associated with foliar absorption decreased, while the influence of input parameters associated with root uptake increased. These phenomena were more remarkable in case of the deposition of non-growing stages than growing stages, and in case of $^{90}Sr$ deposition than $^{137}Cs$ deposition. In case of deposition during growing stages of pasture, the input parameters associated with the characteristics of cattle such as feed-milk transfer factor and daily intake rate of cattle were relatively important in contamination of milk.