• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.86-86
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• 2003

Research has been in progress for more than a decade to production of useful proteins by genetic modification in cattle. However, the levels of protein production in transgenic cattle have been reported very low. To enhance protein production in transgenic animal, we tried homologous recombination to donor cells for production of transgenic clone cattle through nuclear transfer procedure. Thus, we constructed the two targeting vectors of human thrombopoietin (TPO) at bovine $\beta$-casein locus using homologous recombination with 13.6 kb and 9.6 kb homology. In two targeting vectors, positive selection was through the neomycin resistance gene and negative selection was by the diphtheria toxin (DT). Gene targeting was attempted in bovine embryonic fibroblasts (bEF) and bovine ear skin fibroblasts (bESF). To determine the most appropriate concentration of neomycin for bEF and bESF, G4l8 resistance was confirmed by culturing the cells in various concentrations of the drug and both of the cells were optimally selected at $900 \mu g/ml$ of neomycin. The transfected bEF and bESF by the targeting vectors were colonized efficiently at the ratio of DNA to transfection reagent such as $4 \mu g$:2 ${mu}ell$ and $1 \mu g$:$2 \mu l$. Comparing number of healthy clones from passage 4 to passage 8, bESF (17%) persist in culture for much longer than bEF (6%). The two gene-targeted bESF clones of 30 random-integrated clones with 9.6 kb homology length were confirmed, however, nothing was out of 72 random integration clones with 13.6 kb homology length, The DT also worked more efficiently in clones transfected with the vector of 9.6 kb homology length. Our data suggests that the choice of donor cell for long culture period should be considered to obtain targeted cell clone, and the gene-targeting frequency and the DT working efficiency are dependent on the length of target homology.

• Microbiology and Biotechnology Letters
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• v.37 no.3
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• pp.258-265
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• 2009

A study on livestock environment improving agents was conducted; top two brands (A and B) in the market, bottom two brands (E and F) based on market shares and two newly developed agents (C and D) were measured for viable count and tested for resistance towards antibiotics prohibited against livestock feeds. Test results revealed that the measured viable count of agents A and B matched those on the labels were identical; however agent E lacked information on viable counts nor the intended usage, while the measured viable count of agent F was less than the label-stated count. No correlation was found between the antibiotic-resistance test and market share, and most of the agents excluding B were found to display resistance case of Lincosimides such as Lincomycine and Clindmycin, resistant bacteria were found, with the except of agent B. Amoxicillin, Ampicillin and Penillin (type-Penecillins) and Erythromycin (type-Macrolide) were shown to contain resistant bacteria, with the except of agents Band E; the same for Norploxacin (type-Quinoline) and Neomycin antibiotics. Aminoglycosides such as Gentamycin and Streptomycin contained resistant bacteria, excluding agent B. Oxytetracyclin (type-Tetracycline), which is banned for use as resistant bacteria showed the highest sensitivity among the 12 antibiotics, revealed positive results in the test for resistant bacteria; again excluding of agents Band E. These results reveal that many agents contained resistant bacteria despite the fact that they were prohibited; this calls for a more accurate display of the facts and specifications, systematic distributions and strict verification processes of environment improving agents.

• Korean Journal of Food Science and Technology
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• v.42 no.6
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• pp.643-647
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• 2010

This research was carried out to investigate residues of neomycin, streptomycin, dihydrostreptomycin, amitraz, 2,4-dimethylaniline (one of amitraz's metabolites), and coumaphos in honey in order to intensively control their use following the establishment of Korean maximum residue limits (MRLs) for veterinary drugs in honey in 2007. To monitor for residues, 110 honeys and food products with honey were collected and analyzed. The collected honeys included acasia, mixed flower, chestnut, rape flower, jujube, and native types. Neomycin, streptomycin, dihydrostreptomycin, oxytetracycline, and amitraz were not detected among samples. Coumaphos was found in the Korean acasia honey at 0.02 mg/kg, but its concentration was under the MRL (0.1 mg/kg) for coumaphos. According to the results, there were no violations of the Korean MRLs of veterinary drugs in honey.

• Proceedings of the PSK Conference
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• 2003.10a
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• pp.93-93
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• 2003

RNA plays an important role in numerous biological processes but little is known about the interactions between small organic molecules and RNA. Our previous work has shown that the heterodimeric compound designed by conjugation with neomycin and loop-specific chemical bind to the stem-loop structured RNA motifs. In the present study, heterodimer was used, in a reverse way, as a probe to identify structured RNA motifs. (omitted)

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.161.2-161.2
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• 2003

In order to investigate the pathogenic genes and genetic relationships of Y. pseudotuberculosis, we isolated 9 strains of Y. pseudotuberculosis from about 380 spring water sites in Seoul and carried out antibiotic susceptibility test, biological test and molecular typing. All isolated strains were distributed throughout the northeast area in Seoul (Mt. Bookhan, Mt. Soorak, Mt. Boolam and etc...).Antibiotic susceptibility test revealed that all the strains were susceptible to chloramphenicol, gentamicin, neomycin and amoxicillin/clavulanic acid, but were resistant to novobiocin and vancomycin. (omitted)

• Korean Journal of Food Science and Technology
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• v.31 no.5
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• pp.1357-1362
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• 1999

For the study of human intestinal environments with the intestinal bacteria producing ${\beta}-glucuronidase\;and \;7{\alpha}-dehydroxylase$, genus Clostridium, known as the producer, were isolated from the fecal microflora. Through screening twice for one person, fecal microflora without major bacterial group seemed to be changed, which indicated the microflora would be changeable by the diet factors. With using Neomycin-Nagler selective medium during the screening, 14 Clostridium spp. were isolated and then the harmful enzyme activities were determined. Isolate-11 among them produced strongly ${\beta}-glucuronidase$ and its activity was 0.021 unit/mg Protein. However, the strain producing $7{\alpha}-dehydroxylase$ was not isolated. The Isolate-11 was tentatively identified as Clostridium scatologenes through cultural and physiological characteristic.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.9
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• pp.1336-1342
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• 2005

The present research work was conducted to evaluate the beneficial effects as well as the safety aspects of lactobacilli as probiotic. Lactobacilli were isolated from poultry faecal samples, feed samples and from some known preparations procured from poultry feed manufacturers. L. acidophilus and L. sporogenes were tested for the antibacterial activity against four poultry pathogens viz. Escherichia coli, Salmonella spp., Proteus spp. and Pseudomonas aeruginosa. Cell free supernatant (CFS) of L. acidophilus exhibited significantly higher antibacterial activity against Salmonella spp. at original pH (4.50${\pm}$0.02). At the adjusted pH (6.50${\pm}$0.02) significantly higher antibacterial activity was recorded against indicator organism except for P. aeruginosa. Likewise, L. sporogenes exhibited similar antibacterial activity at original as well as adjusted pH except for E. coli. Antibacterial activity against E. coli was significantly higher at adjusted pH than at original pH of CFS. The competitive exclusion of E. coli by lactobacilli over the intestinal epithelial cells (IEC) was checked. L. acidophilus strain I, which was of poultry origin, exhibited maximum attachment over IEC as compared to other three strains of non-poultry origin viz. L. acidophilus strain II, L. sporogenes strain I and II. Overall, L. acidophilus exhibited higher competitive exclusion as compared to L. sporogenes. All the lactobacilli of poultry origin were most sensitive to penicillin G, amoxycillin, ampicillin and chloramphenicol, least sensitive to sulphamethizole, ciprofloxacin, neomycin, norfloxacin and pefloxacin and resistant to metronidazole and nalidixic acid. The isolates from probiotic preparations were most sensitive to ampicillin, amoxycillin and tetracycline, least sensitive to sulphamethizole, norfloxacin, neomycin and ceftriazone and resistant to nalidixic acid and metronidazole. Eight of the multiple drug resistant lactobacilli isolates were studied for the presence of plasmids. Plasmids could be extracted from six isolates of lactobacilli. These plasmids could be responsible for bacteriocin production or for antibiotic resistance of the strains. The lactobacilli need further studies regarding their safety for use in the probiotic preparations.

• Korean Journal of Veterinary Service
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• v.23 no.1
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• pp.61-69
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• 2000

Thirty-one dairy cow from two farm(more than 500,000 cells/ml of bulk milk) in Kyongbuk northern province were selected because of their high somatic cell(more than 500,000 cells/ml of milk In individual cow). Each cow received. staphylococcus aureus vaccine(Labac Staph) and immunostimulant(Ultracon) by intramuscular injection to be repeated every fifteen days for S times. The present study was investigated variation of somatic cell after administration of Labac Staph and Ultracon, and antibiotics resistance of isolated staphylococcus spp from milk in selected cow. The results obtained through the survey were summarized as follows ; 1. Ten dairy cow was injected in A farm. Chronic mastitic two cow after 2rd injection was weeded out the herd. Decrease rate of somatic cell after 1st, 2nd, ,3rd, 4th and 5th administration were 41.4%, 35.6%, 56.4%, 65.4% and 36.7%, respectively. Twenty-one cow was injected in B farm. Chronic mastitic five cow after ,3rd injection was weeded out the herd. Decrease rate of somatic cell after 1st, 2nd, 3rd, 4th and 5th administration were 36.9%, 59.9%, 24.5%, 62.6% and 78.4%, respectively. 2. In A farm, isolated staphylococcus spp were identified as S hyicus 2 strains(11.8%), coagulase negative staphylococcus 15 stains(89.2%) and S epidermidis 6strain(35.3%). In B farm, isolated staphylococcus spp were identified as S aureus 19 strains(55.98%) and coagulase negative staphylococcus 15 strains (44.2%). 3. In A fm, antibiotics resistant rate of isolated staphylococcus spp was high at ampicillin, penicillin and kanamycin, and middle at neomycin, streptomycin and erythromycin. in B farm, antibiotics resistant rate was moderate at ampicillin, penicillin, gentamicin, ka-namycin, neomycin, streptomycin, erythromycin and tetracycline, and coagulase negative staphylococcus spp was moderate at streptomycin.

• Korean Journal of Plant Tissue Culture
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• v.28 no.1
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• pp.53-58
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• 2001

To develop herbicide-resistant cucumber plants (Cucumis sativus L. cv Green Angle) embryogenic suspension cultures were co-cultured with Agrobacterium tumefaciens strain LBA4404 carrying a disarmed binary vector pGA-bar. The T-DNA region of this binary vector contains the nopalin synthase/neomycin phosphotransferase Ⅱ (npt Ⅱ) chimeric gene for kanamycin resistance and the cauliflower 35S/phosphinothricin acetyltransferase (bar) chimeric gene for phosphinothricin (PPT) resistance, After co-cultivation for 48 h, embryogenic calli were placed on maturation media containing 20 mg/L PPT. Approximately 200 putatively transgenic plantlets were obtained in hormone free media containing 40 mg/L PPT. Northern blot hybridization analysis confirmed the expression of the bar gene that was integrated into the genome of five transgenic plants. Transgenic cucumber plants were grown to maturity. Mature plants in soil showed tolerance to the commercial herbicide (Basta) of PPT at the manufacturer's suggested level (3 mL/L).

• Journal of the Society of Cosmetic Scientists of Korea
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• v.27 no.1
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• pp.17-27
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• 2001

A cell-based assay system for monitoring NF-$textsc{k}$B activity was developed to determine the influence of activated NF-$textsc{k}$B in human HaCaT cells. The pNF-$textsc{k}$B-SEAP-NPT plasmid that permits expression of the secreted alkaline phosphatase (SEAP) reported gene in response to the NF-$textsc{k}$B activity and contains neomycin phosphotransferase (NPT) gene for the geneticin resistance in host cells was constructed and transfected into human keratinocyte cell line HaCaT. Human HaCaT transfectant cells secreted the SEAP enzyme into the culture medium in a time-dependent manner until 72h. NF-$textsc{k}$B activities were measured in the SEAP reporter gene assay using a fluorescent detection method. The treatment of HaCaT cell transfectants with known antioxidants [e.g., N-acetyl-L-cysteine and vitamin C] showed inhibition of NF-$textsc{k}$B activity in a time-and concentration-dependent manner. The phorbol 12-myristate 13-acetate (PMA) known as a stimulator of NF-$textsc{k}$B expression demonstrated that it increased NF-$textsc{k}$B activity in a time- and concentration-dependent manner. This assay system could be used to determine the quantitative measurement of NF-$textsc{k}$B activity in the human skin and allow the screening of anti-inflammatory agents from various synthetic chemicals and natural products for dermatological purpose. Abbrevitions used: NF-$textsc{k}$B, nuclear factor kappa B; I-$textsc{k}$B, Inhibitory kappa B; SEAP, secreted alkaline phosphatase; NPT, neomycin phosphotransferease; PCR, polymerase chain reaction: dNTP, deoxynucleoside triphosphates; DMEM, dulbecco’s modified eagle medium; FBS, fetal bovine serum; PBs, phosphate-buffered saline; MUP, 4-methylumbellifery phosphate; NAC, N-acetyl-L-cysteine; DMSO, dimethyl sulfoxide; PMA, phorbol 12-myristate 13-acetate.