• KSBB Journal
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• v.23 no.1
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• pp.44-47
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• 2008

Anthracycline antibiotics doxorubicin (DXR) is clinically important cancer therapeutic agent produced by Streptomyces peucetius. DXR result by further metabolism of rhodomycin D (RHOD) and require a deoxy-sugar component for their biological activity. In this study, production of TDP-L-daunosamine and its attachment to ${\varepsilon}$-rhodomycinone (RHO) to generate RHOD has been achieved by bioconversion in Streptomyces venezuelae that bears eleven genes. S. peucetius seven genes (dnmUTJVZQS) were transformed by plasmid and S. venezuelae two genes desIII, IV and two more S. peucetius drrA, B genes were integrated into chromosomal DNA. To generate the feeding substrate RHO, 6L S. peucetius grown on agar plate was harvested, extracted with organic solvent and then purified using preparative HPLC. Recombinant S. venezuelae grown on agar plate containing RHO was harvested and its n-butanol soluble components were extracted. The glycosylated product of aromatic polyketide RHO using heterologous host S. venezuelae presents the minimal information for TDP-L-daunosamine biosynthesis and its attachment onto aglycone. Moreover, the structure of auxiliary protein, DnrQ, was predicted by fold recognition and homology modeling in this study. This is a general approach to further expand of new glycosides of antitumor anthracycline antibiotics.

• The Journal of the Korean Society for Microbiology
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• v.21 no.1
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• pp.1-16
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• 1986

Fifty-one strains of Pseudomonas aeruginosa were isolated from various clinical specimens. Among them, 26 (51%) strains were gentamicin-resistant (Gm') and 25 (49%) were susceptible to gentamicin (Gm'). The frequencies of resistant strains to piperacillin (Pi), cefotaxime, moxalactam, cefoperazone (Cz), and amikacin (Ak) ranged from 21.6 to 31.4%, and $MIC_{50}$ of these drugs were lower than the critical concentrations of susceptibility and resistance. Thirty (58.8%) strains were multiply resistant to 12 or more drugs. All Gm' strains were multiply resistant to 12 or more drugs and one was resistant to all 18 drugs tested, while only four Gm' strains were multiply resistant to 12 drugs and the multiplicity of resistance of the other Gm' strains were less than 10 drugs. Resistance to Gm appeared to have a significant correlation with the resistance to tobramycin (Tb), Ak, Pi, and Cz. All Gm' strains were resistant to Tb and about 38.4 to 46.1% of them were resistant to Ak, Pi, and Cz. The incorporation of $Ca^{++}$ and $Mg^{++}$ ions in Mueller-Hinton agar (MHA) did not influence the MICs of Gm, Tb, carbenicillin (Cb), Pi, and Cz as compared with the results obtained in MHA without these ions. Gm strains were studied on the combined effect of beta-lactam antibiotics and aminoglycosides by the methods of checkerboard and modified paper strip diffusion. Most Gm' strains showed significant synergistic effects by the FIC index between Ak and three beta-lactam antibiotics; Cb, Pi, and Cz, but these results did not in agreement the results obtained through the method of modified paper strip diffusion test. In order to know the nature of the drug resistance of P. aernginosa, the plasmid profile analysis was studied. Agarose gel electrophoresis of lysates processed by the method of Kado and Liu showed one or more plasmids in 22 (43.1%) strains. A group of 19 strains showed at least one band of plasmid and three strains two bands. The range of the molecular weight of plasmids was 3.8 to 243 Mdal. All strains carrying large plasmids larger than 200 Mdal were isolated from wound specimens. Three Gm' strains also harboured the plasm ids of 13 to 203 Mdal.

• Applied Biological Chemistry
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• v.40 no.2
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• pp.157-162
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• 1997

A novel compound, named YH-487, was synthesized by attaching the thiol and aminothiazole residue to $C_3$ and $C_7$ position of 7-aminocephalosporanic acid (7-ACA). The therapeutic efficacy on infected animals, pharmacokinetics in vivo and the effect on intestinal microflora of YH-487 were examined. The pharmacokinetics of YH-487 were similar to that of cefotaxime, a third generation ${\beta}-lactam$ antibiotics, in rat. Upon in vivo administration, YH-487 was predominantly delivered to kidney, and mostly excreted through kidney without making any metabolites. The therapeutic efficacy of YH-487 to animal infected with E. coli was three times and twenty times higher than that of cefotaxime and cefotiam, respectively, In vivo administration of YH-487 to Sprague-Dawley rats significantly decreased the population of intestinal gram negative species such as Enterobacteria and Barteroides. However, no significant changes were obseved in gram positive species such as Lactobacillus, Bifidobacteria and Staphylococcus. In addition, continuous administration of YH-487 did not increase the possibility to induce resistant strains in intestinal microflora.

• Korean Journal of Agricultural and Forest Meteorology
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• v.7 no.4
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• pp.296-302
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• 2005

We investigated changes in photosynthetic characteristics of P. davidiana in order to understand damage patterns to photosynthetic apparatus under drought stress. Root sprout saplings of P. davildiana were treated with $0\%,\;2\%,\;5\%,\;and\;10\%$ of 300ml polyethylene glycol (PEG) once a weer far one month. After one month, we measured photosynthetic parameters and analyzed the photochemical and $CO_2$ fixation systems. Photosynthetic rate, stomatal conductance, and respiration rate in the leaves of P. davildiana decreased according to increasing stress strength. In the photochemical system, quantum yield of PSII was reduced by the increment of PEG concentration, The decrease of apparent quantum yield was related to reduction of electron transport. Respiration rate decreased with an increase in PEG concentration, whereas photorespiration rate in the $CO_2$ fixation system increased. In conclusion, photosynthesis of P. davidiana responded sensitively under drought stress, and the sensitivity depended upon the strength of water stress. P. davidiana exhibited an increase of water use efficiency under water stress.

• Microbiology and Biotechnology Letters
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• v.20 no.4
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• pp.483-490
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• 1992

In order to understand the transfer behavior of a particular gene in water environments, kanamycin resistance ($Km^r$) gene was tracked by Southern hybridization with DNA probe in its conjugal transfer. A $Km^r$ natural bacterial isolate and genetically modified microorganisms (GMMs) constructed from the isolate were used as donor for conjugal transfer of the $Km^r$ gene. The transfer frequencies of the $Km^r$ gene from GMM strains were generally 10 to 100 times higher than those from the natural isolate. The conjugants obtained from GMM strains in LB broth had more plasmids newly appeared, and particularly the conjugants in A Wand FW waters revealed more rearrangement in their plasmids as a function of conjugation time. When plasmids of the conjugants obtained in LB broth were Southern hybridized with DNA probe of the $Km^r$ gene, the $Km^r$ plasmids in the conjugants were detected at the same position of the plasmids in donor cells, in spite of the fact that the plasmids were highly rearranged in conjugant cells. But the $Km^r$ plasmids in the donor of DKI and DKC601, and DKC600 were not identified in the conjugants obtained after 50 h conjugation in AW and after 30 h in AW, respectively. The size of the $Km^r$ plasmids showing hybridization signal were a little changed in the conjugants obtained in A Wand FW waters. Therefore, the method of Southern hybridization with DNA probe was proved to be very specific and useful for tracking of particular genes in water environments.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.27 no.1
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• pp.69-82
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• 1994

In order to find out physiological effects of diets supplemented with seamustard (Undaria pinnatifida) on the growth, survival rate, body compositions and blood properties of young rockfishes (Sebastes schlegeli) in range of average total length from $2.99{\pm}0.23\;cm\;to\;18.52{\pm}1.07\;cm$ and average body weight from $1.03{\pm}0.18\;g\;to\;120.64{\pm}19.32\;g$, experiments were performed for 140 days by feeding four experimental diets supplemented with $0\%,\;3\%,\;5\%\;and\;7\%$ of seamustard powder. In addition, the tests on tolerance of the fishes against low $O_2$ saturation and starvation were carried out after the feeding experiments. The fishes fed diet supplemented with $5\%$ of seamustard powder revealed the best results in growth of total length and body weight. Crude lipid content in the whole viscera of fishes fed diets supplemented with seamustard powder was higher than that of fishes fed diet without seamustard powder, while the moisture, crude protein, crude lipid and crude ash composition in the dorsal muscle did not show any remarkable differences among diet groups with or without seamustard powder. Hematocrit and mean number of red blood cell in fishes fed diets supplemented with seamustard powder was elevated, despite of no notable changes in mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration. The resistance of the fish to low $O_2$ saturation was elevated by feeding seamustard powder. Upon the starvation of fish for 31 days after the feeding experiments, body weight loss of three groups fed diets with seamustard was smaller compared with the group fed diet without seamustard.

• Korean journal of applied entomology
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• v.44 no.2
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• pp.109-114
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• 2005

This study was conducted to investigate the life cycle of Tipula latemarginata Alexander in Korea. The field surveys for the life cycle of the species were carried out at the two sites of Neaseong Stream area in Bongwha County from January 2001 to December 2002. Also many individuals of the species were reared in laboratory to investigate the life cycle. T latemarginata appeared to have three generations a year under the rearing conditions at room temperature. All the processes of life cycle of the species, when reared at room temperature from September 2001 to March 2002, were as follows: Eggs usually hatched between 4 and 10 days after oviposition. First instar larvae grew rapidly and molted to the second instar in 7-9 days. Second instar larvae spent 5-7 days for next molting and third instar period lasted approximately 8-12 days. Fourth instar larvae spent 6 weeks to 5 months for pupation. Especially the duration of fourth instar larval existence was greatly lengthened and served as the overwintering stage. The duration of pupal stage was 6-10 days. In the field, T. latemarginata also appeared to have three generations a year at the favorable habitats.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.26 no.4
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• pp.287-292
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• 1981

The field studies were carried out in paddy field over a four year period in order to find out the effects of butachlor, nitrofen, oxadiazon or CG 102, benthiocarb-S, and bentazon applied successively to the same paddy field for four years on weed succession and rice yields under different fertilized conditions including compost, chemical fertilizer and straw application. Total dry weight of weeds was steadily increased yearly over 4 year period regardless of fertilized conditions, and significantly higher increase of weed dry weight was observed on non-fertilized and compost plots. The most dominant weed species was Scirpus hotarui, and Potamogeton distinctus, Eleocharis kuroguwai and Cyperus serotinus were predominated on compost plot, E. kuroguwai and E. aclularis on non-fertilized plot, E. kuroguwai, C. serotinus, and Monochoria vaginalis on chemical fertifizer plot, and C. serotinus on straw plot. When the same herbicides were used continuously on the same plots, weed control effect was decreased and thus weed population was greatly increased particularly on butachlor and nitrofen treated plots. P. distinctus, E. kuroguwai, and C. serotinus were predominated on butachlor treated plot, P. distinctus and C. serotinus on nitrofen treated plot, C. serotinus on benthiocarb-S treated plot, C. serotinus and P. distinctus on oxadiazon or CG 102 treated plot and P. distinctus on bentazon treated plot. Annual weeds were slightly increased by repeated annual application of oxadiazon or CG 102 and benthiocarb-S, whereas perennial weeds were predominated by successive application of butachlor, nitrofen. and bentazon for 4 years. Yield reduction of rice became prominent by successive application of same herbicides. particularly butachlor and nitrafen. This results suggested that successive annual application of same herbicides should be limited and herbicide combination or herbicide rotation should be applied to control the remaining weed species.

• Microbiology and Biotechnology Letters
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• v.40 no.3
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• pp.274-277
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• 2012

Cytokinesis is the final stage of cell division, dividing one mother cell into two daughter cells. For the cutting of a plasma membrane during bacterial cytokinesis, a tubulin homolog FtsZ protein is recruited from the cytoplasm to the division site. FtsZ protein polymerizes in a GTP-dependent manner and its N-terminal domain has a GTPase activity. In this study, we have begun to characterize FtsZ from Staphylococcus aureus (SA). Full-length SA FtsZ was cloned into pRSFDuet-1 vector and the clone was transformed into a BL21 (DE3) star cell. The recombinant SA FtsZ protein was purified using Ni-NTA affinity chromatography and dialysis. Using a spectrofluorometer, we showed that SA FtsZ undergoes a GTP-dependant polymerization in vitro. The polymer of the SA FtsZ protein disappeared after a few minutes, suggesting that the polymer is degraded as the GTP is consumed. This assay system may well be applied for inhibitor screening targeting S. aureus FtsZ.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.642-642
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• 2012

최근에 들어 지구온난화에 따른 기후변화의 영향으로 국지성 집중호우와 돌발성 호우가 한반도 뿐 아니라 전 세계적으로도 많이 나타나고 있고, 그로 인한 이상홍수의 발생이 우리나라의 인명 및 재산피해를 날로 증가시키고 있는 추세이다. 그러나 현재 국내의 홍수방어시스템은 정확도 및 선행시간 확보 등의 측면에서 국민들의 요구수준까지는 그 역할을 수행하지 못하고 있는 실정이다. 또한 최근 4대강 살리기 사업을 통해 수행된 보 설치 및 하도 준설로 인해 하천환경의 변화가 크게 발생하여, 보다 정확하고 신속한 홍수위 예측기법이 요구되고 있는 실정이다. 이에 따라 현재 4대강 홍수통제소에서는 정확한 홍수위예측을 위해 4대강 본류 및 주요 지류에 대해 수리모형을 구축하고 있고, 기존의 저류함수모형에 의한 강우-유출 해석기법을 적용하여 주요 지류에 대한 유입량을 산정하기 위한 모형을 구축중에 있다. 국내 홍수방어 시스템에 현재까지 사용되어 오고 있는 저류함수모형 및 수위-유량 관계식을 이용한 방법은 물리적 기반의 홍수예측모형으로 유역의 지형학적 인자와 그에 따른 여러 변수를 포함하기 때문에 하천환경의 변화로 인해 각각의 추적과정에서 오차들이 발생하여 해석결과에 영향을 미치는 단점이 있다. 이에 반해 데이터 기반 모형은 강우-유출 모형에서 사용되는 많은 수문학적 자료 및 매개변수들의 사용 없이 오직 수위 및 강우측정 자료만을 이용하여 홍수를 예측하는 모형이다. 본 연구에서는 낙동강 유역에 대해 보다 정확한 홍수위 예측을 위해 현재 낙동강홍수통제소에서 구축중인 낙동강 본류의 수리모형의 주요 지류의 유입량 산정을 위해 기존의 물리적 기반 모형이 아닌 뉴로-퍼지(Neuro-Fuzzy) 모형을 이용한 data 기반 모형을 적용해 기존 물리적 기반 모형과 비교 분석 하고자 하였다. 낙동강의 주요지류인 감천, 금호강, 남강, 내성천, 밀양강, 반변천, 위천, 황강을 적용유역으로 선정하여 유역별로 티센망을 구축하였고, 각 지류별로 수위관측소를 선정하여 최근 10년동안 낙동강유역의 홍수예 경보가 발령되었거나 많은 비가 온 사상을 선정해 모형을 검증하였다. 모형은 실시간 수위측정 자료와 강우자료 및 해당유역 댐의 방류량 자료를 이용해 유역별 최적 입력자료 조합을 선정하여 간단하게 구축할 수 있었다. 또한 10분 단위 및 30분 단위의 입출력 자료로 모형을 구축하여 비교하였다. 이번 연구에서 수행한 낙동강유역에서의 뉴로-퍼지(Neuro-Fuzzy) 모형을 이용한 홍수예측기법을 통해 몇가지 data만으로 유역의 주요지점에 대한 홍수위와 홍수량을 예측할 수 있음을 확인할 수 있었다. 모의 결과는 실측치와 비교해 정확도 면에서 우수함을 보여 주었으나 예측시간이 길어질수록 실측치의 경향을 벗어나는 결과를 보였다. 그러나 실시간 홍수예 경보에 있어서는 만족할만한 선행시간을 확보할 수 있었다. 구축된 Data 기반 모형이 물리적 기반 모형과 더불어 낙동강 홍수예 경보를 위한 모형으로 사용될 수 있다면 보다 효율적인 예 경보 체계 구축에 도움을 줄 수 있을 것으로 판단된다.