Pseudomonas sp. DJ-12의 pcbCD 유전자의 클로닝과 Escherichia coli에서의 발현

김치경,성태경,남정현,김영창,이재구,Kim, Chi-Kyung,Sung, Tae-Kyung,Nam, Jung-Hyun,Kim, Chang-Young,Lee, Jae-Koo 한국미생물학회 1994 미생물학회지 Vol.32 No.1

The pcb genes of Pseudomonas sp. DJ-12 coded for the catabolism of polychlorinated biphenyl (PCBs) and biphenyl. The products of the pcbCD genes were 2,3-dihydroxy-4'-chlorobiphenyl dioxygenase and meta-cleavage product (MCP) hydrolase, which acted on degradation of 2,3-dihydroxy-4'-chlorobiphenyl to 4-chlorobenzoate. The pcbCD genes were cloned in E. coli XLl-Blue, and then the pcbD gene was further subcloned. As a metabolite transformed from 2,3-dihydroxybiphenyl by the cloned cell of E coli CU103, benzoate was detected by the resting cell assay. The enzyme activities of 2,3-dihydroxybiphenyl dioxygease and MCP hydrolase produced in the cloned cells E. coli CU103 and CU105 were about 17 and 3 times higher than those of Pseudomonas sp. DJ-12, respectively.

오존에 의한 bacteriophage f2의 살균작용(殺菌作用)

김치경,Kim, Chi-Kyung 한국현미경학회 1981 Applied microscopy Vol.11 No.1

Bacteriophage f2 were treated with ozone at various concentrations for 20 minutes. The inactivation kinetics of f2 phage were examined during ozonation. In order to study the mode of action of ozone on the phage f2, absorption of the phage to the host pili was meassured by utilyzing radioactivity of tritium incorporated into the phage RNA. Sucrose density gradient analysis and electron microscopy were also used to prove the mechanism of ozone inactivation of the phage. Strucural proteins of the phage were broken by ozonation into many protein subunits. The extent of phage breakage was proportional to ozone concentration and reaction time. Percent decrease of the phage absorption to the host pili was coincident with the rate of ozone inactivation of the phage. Ozone inactivation of bacteriophage f2 was shown to be caused by the breakage of the structural protein and blockage of the phage absorption to the host pili.

하천수에서 Campylobacter jejuni 의 오염도와 그 생존율에 관한 연구

김치경,오학식,염곤,조민기 ( Chi Kyung Kim,Hak Shik Oh,Kon Ryeom,Min Ki Cho ) 한국하천호수학회 1986 생태와 환경 Vol.19 No.3·4

Campylobacter jejuni isolated from river and lake waters and chicken samples were examined for their contamination and survival in surface waters and for inactivation by chlorination. The isolation rates of C. jejuni from chicken samples were 50 to 100%, while only one out of 48 studies was positive from the surface water. When the organisms suspended in sterile river water were incubated at 4℃, they survived upto 20 days, but they died off after 1 day incubation at 30℃ or above. The in situ survival studies of C. jejuni in the waters of Dsecheong Dam and Han-river (1st bridge) revealed that they survived upto 14 days in winter, but for shorter period of time in spring and summer. The survival rates of the organism in the deeper water were a little longer than in the surface water, but the rates were not different between the both water environments. When the organisms were treated with 0. 5, 1. 0 and 2. 0 ㎎/ℓ chlorine solution at pH 7. 0 and 15℃ for 60 minutes, they were inactivated by about 1, 4, and 6 logs, respectively, The inactivation rate was increasingly affected by lowering the reaction pH and by increasing the reaction temperature.

Analysis for Torsion of Hollow Beam by Least Squares and Boundary Elements Method

김치경,배준태,Kim, Chi-Kyung,Bae, Joon-Tai Computational Structural Engineering Institute of 2012 한국전산구조공학회논문집 Vol.25 No.2

In this paper we are concerned with the performance of structural stability of torsion in square cross section of a beam with holes. The critical load is defined as the smallest load at which the equilibrium of the structure fails to be stable as the load is slowly increased from zero. The beams subjected to torsion are frequently encountered in general structures and these forces influence to the stability of structure. The boundary element method is found to be very efficient and accurate for the analysis of torsion problems including complex boundary conditions with respect to its simplicity and generality. In this paper, it is required to derive the boundary element formulation for torsion problem and integrate directly on the discrete boundary. To investigate the validity of the developed computer program, three distinctly solid cross-sections which are elliptical, rectangular and triangular one are analyzed, and comparisons are made with analytical approaches where these can also be used.

하천수의 오염도와 Escherichia coli 의 생존율과의 상관성에 관한 원위치 실험연구

김치경,정만희,김근식 ( Chi Kyung Kim,Man Hee Chung,Keun Sik Kim ) 한국하천호수학회 1984 생태와 환경 Vol.17 No.1·2

The survival of enteric bacteria in river water has been extensively studied under laboratory conditions or by jug method in river, but the correlations between the survival rate and the level of water pollution have not been reported. In this study, the survival of two strains of Escherichia coli (ATCC #25922 and a fresh isolate from polluted water) was comparatively studied in gradually polluted river waters by in situ method using dialysis sac. In all cases which the dialysis sacs containing sterile or non-sterile river water inoculated with E. coli were examined in the river waters, the survival rates were proportionally increased by the level of water pollution. The higher survival rate of E. coli in the more polluted rivers seems to be attributed to the higher growth rate of the organism on the organic pollutants in spite of the higher number of predators. Therefore, the high number of E. coli found in the more polluted river is thought to be due to the growth of the existing bacteria, not due to the influx of the bacteria including in domestic sewage. This means that the organic pollutants in river could be not only the primary problem as itself, but also the secondary problems promoting growth of the enteric bacteria in river waters, maintaining them in high number, and increasing the chances for the enteric pathogens to spread to outbreak waterborne diseases.

Caulobacter의 세포(細胞)의 형태(形態) 및 기능(機能)의 분화(分化)에 대한 염소 및 염소화합물의 영향(影響)

김치경,박문국,염곤,Kim, Chi-Kyung,Park, Moon-Kook,Yum, Kon 한국현미경학회 1982 Applied microscopy Vol.12 No.1

Caulubacter is distinctive in the morphology and replication and ubiquitous in the biosphere, especially in every type of aquatic environment. In water and waste-water treatment processes, chlorine and chlorine compounds have been used as a main disinfectant throughout the world. Therefore, Caulobacter in the waters should be affected by chlorination of the waters. The objective of this study is to determine the effects of the disinfectants on Caulobacter cells and on the developmental processes of the cells. The Caulobacter swarmer cells were disinfected by chlorine at pH 7.0 minutes of the reaction with 2.0 mg/l of infected at pH 10.0. The swarmer cells treated with 2.0 or 4.0 mg/l of chlorine for 15 minutes lost their flagella and were observed by electron microscopy to be damaged on their cell surfaces, discharging some cellular materials. When the chlorinated swarmers and untreated control samples were recultivated in fresh PYE broth medium, the control swarmers multiplicated exponentially after one-hour lag phase, whereas the chlorinated swarmers extended the lag phase to about four hours. During the extended lag phase, the cells were proved by electron microscopy to be grown and be in predivisional step, but no swarmer cell was found. When the stalked cells were chlorinated, almost all the cells were observed to have their stalks broken and some cellular materials discharged. In those samples recultivated, many cells differentiated to possess an abnormally elongated stalk with several crossbands on it. This suggests that the chlorine-shocked Caulobacter cells can develope to abnormal morphology in water environments which they can survive and regrow in.

상실성빈맥의 수술치험 -1예 보고-

김치경,정진용,곽문섭,김세화,이홍균,홍순조,Kim, Chi-Kyung,Jeong, Jin-Yong,Kwack, Moon-Sup,Kim, Se-Wha,Lee, Hong-Kyun,Hong, Sun-Jo 대한흉부심장혈관외과학회 1988 Journal of Chest Surgery (J Chest Surg) Vol.21 No.6

Supraventricular tachyarrhythmias are readily characterized and understood, but the surgical procedures for their correction are complex and not easily mastered. Conversely, ventricular tachyarrhythmias are frequently difficult to characterize and localize electrophysiologically and their basic mechanisms are poorly understood. The role of the surgeon in the treatment of cardiac arrhythmia has changed dramatically during the past decade. This report is a case of 26 years old male with supraventricular tachyarrhythmia. The result of endocardial electrophysiologic study demonstrated accessory pathway connecting left atrium to left ventricle which located at left atrial free wall about 4 cm apart from the coronary sinus orifice. The accessory bundle interruption has been successfully accomplished utilizing the internal open heart technique. The operation consisted of dissection of the atrioventricular fat pad and division of all the superficial fibers going from the ventricle to the annulus. Following this, cryoablation made with cryoprobe at - 60$^\circ{C}$ for 90 seconds. The accessory pathway was successfully ablated without specific problems.

흉부질환을 병발한 Von Recklinghausen's disease -2예 보고-

김치경,박재길,이홍균,Kim, Chi-Kyung,Park, Jae-gil,Lee, Hong-Kyun 대한흉부심장혈관외과학회 1980 Journal of Chest Surgery (J Chest Surg) Vol.13 No.2

Von Recklinghausen's disease is a systemic hereditary disorder with varied manifestations in bone, soft tissue, nervous system, and skin, the most common of which is the developement of multiple, small, cutaneous tumors with a characteristic histologic picture. Tumors develop after birth and before puberty in most cases, and they increase in number until old age. Malignant neoplasms that complicate multiple neurofibromatosis include gliomas of the optic nerve, astrocytomaas of the cerebral and cerebellar hemispheres, and sarcomas of peripheral nerves (femoral, tibial and intercostal nerves) and somatic soft tissues. Little attention has been paid to the presence of cystic lung disease in association with neurofibromatosis. Currently, most think of thoracic involvement in neurofibromatosis in terms of posterior mediastinal neuroma, pheochrocytoma, meningocele or, less commonly parenchymal pulmonary neurofibromas. Author have experienced 2 cases of Von Recklinghausen's disease. One case developed a hyge malignant Schwannoma in the parietal pleura of left 4th intercostal space and multiple benign neurofibromas (two in intercostal spacees and one in the neck) , and the other has several episodes of pneumothorax resulting from diffuse cystic lung disease which required closed thoracotomy drainage.

Pseudomonas spp.에 의한 4-chlorobiphenyl의 분해 및 Plasmid와의 연관성

김치경,이익근,Kim, Chi-Kyung,Lee, Ik-Keun 생화학분자생물학회 1990 한국생화학회지 Vol.23 No.3

자연계로 부터 분리한 균주 중 4-chlorobiphenyl(4CB) 분해균주로 DJ-12, DJ-26, DJ-77, MS-1003 그리고 FP-6을 사용하여 4CB를 단일 탄소원으로 첨가한 최소배지에서 그들의 생장율과 4CB의 분해율을 조사하였다, DJ-12와 DJ-26 균주는 4CB를 분해할 때 236과 280 nm의 파장에서 각각 흡광하는 중간 대사산물들이 검정되는 것으로 보아 이 균주들은 meta-cleavage pathway에 의하여 4CB를 분해하여 meta-cleavage compound를 거쳐 4-chlorobenzoic acid(4CBA)를 생성한다는 것을 알 수 있었다. 또 DJ-12 균주가 단일 탄소원으로 4CB를 공급할 때 meta-cleavage pathway를 거쳐 retention time이 2.6~2.8 분대에서 검출되는 4CBA를 생성하는 것이 HPLC로 확인되었다. 그리고 DJ-12 균주와 P. putida KT2440을 in vivo cloning하여 얻은 transconjugant들로 부터 plasmid의 특성을 조사해 본 결과, DJ-12 균주에서 4CB 분해유전자가 약 65 kb 정도의 pDJ121 plasmid에 연관되어 있다는 것을 발견하였다. Including the Pseudomonas strains reported in the previous works, two bacterial strains which are able to degrade 4-chlorobiphenyl(4CB) were isolated from natural environments. They were investigated for their ability to degrade 4CB and for growth on 4CB as a sole source of carbon and energy. It was found by UV-scanning spectrophotometry that both strains of DJ-12 and DJ-26 degraded 4CB to produce the meta-cleavage compound and then to 4-chlorobenzoic acid (4CBA) through the meta-cleavage pathway without dechlorination step. The DJ-12 strain was also turned out to degrade 4CB to produce 4CBA as assayed by HPLC. Through conjugation with Pseudomonas putida KT2440, the genes responsible for degradation of 4CB in the strain DJ-12 were found to be associated with a plasmid of about 65kb in size.

Application of the Unstructured Finite Element to Longitudinal Vibration Analysis

김치경,Kim Chi-Kyung Computational Structural Engineering Institute of 2006 한국전산구조공학회논문집 Vol.19 No.1

This paper analyzes the continuous Galerkin method for the space-time discretization of wave equation. The method of space-time finite elements enables the simple solution than the usual finite element analysis with discretization in space only. We present a discretization technique in which finite element approximations are used in time and space simultaneously for a relatively large time period called a time slab. The weighted residual process is used to formulate a finite element method for a space-time domain. Instability is caused by a too large time step in successive time steps. A stability problem is described and some investigations for chosen types of rectangular space-time finite elements are carried out. Some numerical examples prove the efficiency of the described method under determined limitations.