• Korean Journal of Animal Reproduction
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• v.21 no.4
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• pp.397-403
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• 1997

For the ultimate goal of efficient retrovirus vector-mediated transgenic animal production, we tried to increase virus titer by employing three methods: boosting virus production by treating virus-producing cells with sodium butyrate, concentration of virus stock by either filtration or ultracentrifugation. Compared to the control, applications of sodium butyrate (5 mM) treatment and filtration resulted in only 3 and 3. 6 folds of titer increases on bovine EBTr target cells, respectively. However, concentration of virus-containing medium by ultracentrifugation showed 12.5 folds of titer increase compared to the control (10${\times}$10$^5$ LacZ$^+$ TU Im), indicating the best method which can enhance retrovirus vector-mediated transgenic animal production.

• Applied Biological Chemistry
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• v.46 no.1
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• pp.7-11
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• 2003

Cloning and expression of copper-binding peptide gene in E. coli was carried out to enhance the copper-chelation capacity. E. coli was transformed with pET vector containing the copper-binding region of potato polyphenol oxidase gene and polyhistidine-coding DNA, and the copper content of E. coli harboring each vector was measured. No increase in intracellular copper was observed in E. coli harboring PPOCBpET32 vector, which contains DNA for polyphenol oxidase copper-binding region. Intracellular copper content of E. coli harboring pE728a vector, which contains one hexahistidine unit DNA, was 2,500 ppm after culturing without kanamycin, whereas E. coli harboring pET-his vector, which contains nine hexahistidine unit DNAs was 3,200 ppm.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.36 no.1
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• pp.74-78
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• 1991

This experiment was conducted to know the effects of mutagen treatments on callus induction, plant regeneration and their ploidy in the anther culture of wheat. The winter wheat cultivars, 'apos;and 'apos;Wonkwang'apos;, were treated at the mid or late-uninucreate stage under 4 different doses (100, 200, 500 and 1,000 rad.) of X-ray and 3 different levels(0.1, 0.2 and 0.3 mole) of Ethyl Methane Sulphonate. The anthers treated were set on the C$\_$17/medium for callus induction, and callus induced was transfered to 1/2 MS medium for plant regeneration. The mutagen treatments inhibited the callus induction but increased the plant regeneration in the callus which were induced from the anther set on the medium for the long time of 60 to 80 days. Also, the chromosome number to the regenerated plant varied largely by increasing of haploid plants(n=3x=21) and by occurring of aneuploidy having n=20 and n=22 of chromosome number.aried largely by increasing of haploid plants(n=3x=21) and by occurring of aneuploidy having n=20 and n=22 of chromosome number.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.239.2-239.2
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• 2011

치과재료의 개발은 치과 치료 기술에 있어서 가장 중요한 요소이며, 현재 일반화되고 있는 치과 치료 기술 중 하나가 임플란트 시술이다. 임플란트의 기술 개발은 주로 임플란트 나사의 표면개질을 통한 기능개선에 초점을 ��추어 진행되어지고 있다. 본 연구에서는 Ti 임플란트 표면상에 양극산화법을 적용하여 다양한 지름 및 기공 크기를 갖는 $TiO_2$ 나노튜브를 제조하여 전자빔 조사를 통한 표면개질시 그 특성에 관한 연구를 수행하였다. 특히 전자빔 조사가 Ti/$TiO_2$ 나노튜브 표면상에 존재 가능한 조골세포의 성장 특성에 미치는 영향을 연구하였다. 양극산화법을 이용한 Ti/$TiO_2$ 나노튜브는 전해질로서 HF와 $NH_4F$를 사용하였으며, 20-80 V의 인가 전압하에서 내경 약 80 nm, 외경 약 124 nm 및 길이 약 280 nm-14 ${\mu}m$의 비교적 균질한 지름 및 분포를 갖는 Ti/$TiO_2$ 나노튜브를 제조하였다. 전자빔 조사는 EB-Tech (대전, 한국)의 electron-beam accelerator(Model ELV-4)를 이용하였으며, 1.0 MeV의 빔 에너지로 총 흡수선량이 50 kGy, 500 kGy 및 5,000 kGy로 조사하였다. 전자빔을 조사하기 전 후 Ti/$TiO_2$ 나노튜브 표면상에 조골세포주(Osteoblast cell)의 배양시간의 변화에 따른 효과를 연구한 결과 배양 전 후 전자빔 조사선량의 증가에 따라 조골세포의 흡착률이 증가함을 확인할 수 있었다. 특히 HF전해질을 이용한 $TiO_2$ 나노튜브의 경우 5,000 kGy 조사선량의 전자빔을 조사한 후 조골세포 흡착률이 약 160% 증가하는 결과를 얻을 수 있었다. 전자빔 조사 전 후 조골세포 흡착률의 변화원인은 전자빔 조사 유무에 따른 $Ti^{3+}$와 $Ti^{4+}$의 변화에 기인함을 규명하였다. 이러한 결과는 향후 임플란트용 Ti/$TiO_2$ 나노튜브의 표면 개질시 전자빔의 유용성을 제시한다고 할 수 있다.

• KSBB Journal
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• v.5 no.2
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• pp.167-173
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• 1990

This study is to investigate for obtaining the operating conditions of continuous vinegar production using fluidized bed reactor by Acetobacter aceti cell immobilized in Ca-alginate gel. The optimum conditions obtaining by batch fermentation using fluidized bed reactor were as follows; The fermentation temperature and aeration rate were 3$0^{\circ}C$ and 1.0VVM and the initial concentration of ethanol and acetic acid in medium were 33g/l and 27g/l respectively. The amount of bead used was 25%(w/v). The overall acetic acid productivities of batch fermentations by free cell and immobilized cell were 0.31g/l-hr and 0.48g/l-hr, respectively, at the final acetic acid concentration of 50g/l. In the continuous vinegar production using fluidized bed reactor by immobilized cell under optimum conditions, it was possible to produce 23g/l acetic acid continuously up to 90 days with maximum acetic acid productivity of 2.76g/l-hr at dilution rate 0.12hr-1.

• Journal of Plant Biotechnology
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• v.30 no.4
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• pp.375-380
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• 2003

This study was conducted to establish a practical masspropagation system of Phalaenopsis clones from basal shoot segments. The frequency of PLB (protocorm like body) induction was compared with various explants. Basal shoot segments showed the most successful result of 45％, while root tips, stalk node segments, stalk leaves and mature leaves represented low frequency (below 5％). The PLB induction ratio in the culture of basal shoot segments was examined with 11 different Phalaenopsis varieties, and the majority of varieties, including pink flower lines, showed an about 30％ rate of PLB formation. Especially, when whole basal shoot parts without cutting were inoculated onto PLB induction medium, giant PLB was induced from explant. This giant PLB was green color and big in size compared with normal PLB. When dissected giant PLB segments inoculated onto PLB multiplication medium, only normal size of PLBs were induced from them. PLBs induced by basal shoot culture were transferred onto proliferation medium and then shooting medium, from which normal plants were formed. Therefore, this culture method is considered as effective and practical protocol for Phalaenopsis mericlone production. In addition, it is suggested that clones of an infinite number can be produced consecutively by this culture system through repeated cycles of PLB induction and proliferation using the basal shoot segment of flask plant.

• Journal of the Korean Wood Science and Technology
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• v.35 no.6
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• pp.91-99
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• 2007

Activities of the extracellular enzyme from Fomitopsis palustris, a brown-rot fungi, and by which crystallinity changes of cellulose in the various softwoods, such as Larix leptolepsis, Finns rigida, Finns koraiensis and Finns densiflora by liquid culture, were investigated. Activity of Cellobiohydrolase (CBH) from F. palustris was detected in the every test softwoods culture, showing activities of the Endoglucanase (EG), $\beta$-glucosidase (BGL) and $\beta$-1,4-xylosidase (BXL). It was shown high enzyme activities in the sapwood culture than heartwood of the same wood species, However, the enzyme activities in most of test wood cultures increased with longer incubation time, indicating a possibility of intermix sapwood and heartwood for degradation process by enzyme. Also it was shown that protein patterns of the extracellular enzyme from F. palustris in wood particle substrate of the several domestic softwoods were similar with each other wood species, which suggested the possibility of mixing all softwoods in saccharification by enzyme from F. palustris. Crystallinity reduction value of cellulose by F. palustris was 4.2~20.4% in 4 weeks cultivation, 12.9~28.9% in 8 weeks.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.31 no.5
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• pp.760-766
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• 1998

This study was carried out far isolation and characterization of ammonia oxidizing bacteria (AOB) from aquacultural place and sludges of waste water collected in Pusan. One autotrophic AOB, Nitrosomonas sp. and 8 heterotrophic AOB (2 strains of Bacillus sp., 2 strains of Acinetobacter sp., Xanthomonas sp., Alcaligenes sp., Pseudomonas sp., Sphingobacterium sp.) were isolated. and identified. Variation of total nmmonia nitrogen (TAN) and $NO_2-N$ in mineral salt media containing 10mg/ $\ell$ of NHCl for 15 days in differents 9 strains was measured in order to examine the ablitity of ammonia oxidation. TAN was started to reduce after 4 days incubation and ca. 2 mg/$\ell$ of TAN was decreased after 15 days incubation by Nitrosomonas sp., At that time, $NO_2-N$ was produced to 0.023$\~$0.036 mg/$\ell$. Heterotrophic AOB showed the low ability of ammonia oxidation, 0.02$\~$0,04 mg/$\ell$ of TAN was decreased and $NO_2-N$ was produced to 0.01$\~$0.51 mg/$\ell$ after 15 days. When each strain of 8 heterotrophs was incubated in mimeral salt media containing 10 mg/$\ell$ $NH_4Cl$ and 50 mg/$\ell$ glucose, and 50 mg/$\ell$ $NH_4Cl$ and 5 g/$\ell$ glucose, the diminution of TAN was 1.12$\~$3.38 mg/$\ell$ and 1$\~$20 mg/$\ell$, respectively.

• Korean Journal of Plant Tissue Culture
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• v.26 no.2
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• pp.121-126
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• 1999

Calli were induced from the petiole explants of Pimpinella brachycarpa on MS medium supplemented with 0.5 mg/L 2,4-D and 0.1 mg/L BA after four weeks of culture. Compact clusters of small and dense cells among these calli were selected and suspension-cultured as the source of embryogenic calli. When transferred to MS medium with 0.1 mg/L NAA, the suspension-cultured cells grew to embryogenic callus. Somatic embryos derived from these embryogenic calli developed into plantlets. The cDNA library was constructed in the embryogenic callus and in order to screen the cDNA library, these cDNAs were plated at a density 1.5 $\times$ 10^5 plaques per 15 cm petridish. Among 19 clones showing preferential hybridization with petiole HD-Zip gene, five clones were obtained after second screening. Four clones among them, were highly homologous to P. brachycarpa shoot-tip Phz4 gene, but one clone, Phc5 was about 1.5 kb which has an extra 163 bp to 5' upstream of Phz4. The Phc5 was 1,531 bp containing poly A tails of 18 bases. ATG start codon for Phc5, was located at position 284 with an open reading frame of 906 by which encodes a polypeptide of 302 amino acids. The Phc5 protein revealed that the polypeptides between 135 and 195 contain a homeodomain as the `leucine zipper' motif.

• The Korean Journal of Zoology
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• v.31 no.3
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• pp.177-184
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• 1988

The pattern of progesterone production and secretion of frog(R. dybowskii) follicles was investigated in follicle culture in vitro. Involvement of cAMP in the regulation of the steroid production by the follicles was also investigated by manipulating endogeneous cAMP level with forskolin and/or 3-isoburyl- 1 - methylxanthine(IBMX). Endogeneous follicular progesterone level increased rapidly in one hour of culture by treatment of frog pituitary homogenate(FPH) and reached peak level at 2 hours or later. But the absolute amount of progesterone produced (60-300 pg/follicle) or the peak time of the honnone level was different between individual animals. Basal level of progesterone in untreated sister follicles was very low (around 10 pg/follicle) and nearly undetectable in most cases regardless of culture lime. Secretion level of progesterone by the follicles obtained by measunng the honnone in the culture media was just the reflection of the intrafollicular level. Exogeneously added forskolin, an adenylate cyclase stimulator, and/or IBMX, a phosphodiesterase inhibitor, could mimic FPH action in terms of progesterone production and secretion. Thus, it seems clear that FPH regulates progesterone production via cAMP system in the follicle cells.