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Mineral chemistry and major element geochemistry of the granitic rocks in the Cheongsan area (청산 일대에 분포하는 화강암류의 광물조성과 주성분원소 지구화학)

  • 사공희;좌용주
    • The Journal of the Petrological Society of Korea
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    • v.6 no.3
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    • pp.185-209
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    • 1997
  • Granitic rocks in the Cheongsan area cosist of three plutons-Baegrog granodiorite, Cheongsan porphyritic granite, and two mica granite. Amphilboles from the Baegrog granodiorite belong to the calcic amphilbole group and show compositional variations from magnesio-hornblende in the core to actinolitic hornblende in the rim. Biotites from the three granites represent intermediate compositions between phlogopite and annite. Muscovites from the two mica granite are considered to be primary muscovite in terms of the occurrence and mineral chemistry. Each granitic rock reveals systematic variation of major oxide contents with $SiO_2$. Major oxide variation trends of the Baegrog granodiorite are fairly different from those of Cheongsan porphyritic granite and two mica granite. The latter two granitic rocks are also different with each other in variation trends for some oxides. Thus three granitic rocks in the Cheongsan area were solidifield from the independent magmas of chemically different, heterogeneous origin. The granitic rocks in the area show calc-alkaline nature. The whole rock geochemistry shows that the Baegrog granodiorite and Cheongsan porphyritic granite belong to metaluminous, I-type granite, whereas the two mica granite to peraluminous, I/S-type granite. The opaque mineral contents and magnetic susceptibility represent that the granitic rocks in the area are ilmenite-series granite, indicating that each magma was solidified under relatively reducing environment. The tectonic environment of the granitic activity in the area seems to have been active continental margin. Alkali feldspar megacryst in the Cheongsan porphyritic granite is considered to be magmatic, judging from the crystal size, shape, arrangement, and distribution pattern of inclusions. The petro-graphical characteristics of the Cheongsan porphyritic granite can be explained by two stage crystallization. Under the smaller degree of undercooling the alkali feldspar megacrysts rapidly grew owing to slow rate of nucleation and fast growth rate. At the larger degree of undercooling the nucleation rate and density drastically increased and the small crystals of the matrix were formed.

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A Study on Recovery from Potentially Lethal Damage Induced by $\gamma-Irradiation$ in Plateau-phase Vero Cells in vitro (평형기의 Vero세포계에서 방사선($\gamma$-선) 조사 후 발생한 잠재치사 손상의 회복에 관한 연구)

  • Kim, Il-Han;Choi, Eun-Kyung;Ha, Sung-Whan;Park, Charn-Il;Cha, Chang-Yong
    • Radiation Oncology Journal
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    • v.6 no.1
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    • pp.1-11
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    • 1988
  • Recovery from potentially lethal damage (PLDR) after irradiation was studied in plateau-phase culture of Vero cells in vitro. Unfed plateau-phase cells were irradiated with dose of 1 to 9Gy using Cs-137 irradiator. Cells then were incubated again and left in situ for 0, 1, 2, 3, 4, 5, 6, and 24 hours and then were trypsinized explanted, and subcultured in fresh RPMI-1640 media containing $0.33\%$ agar. Cell survival was measured by colony forming ability. An adequate number of heavily irradiated Vero cells were added as feeder cells to make the total cell number constant in every culture dish. As the postirradiation in situ incubation time increased, surviving fraction increased by PLDR. The rate of PLDR was so rapid that increased surviving fraction reached saturation level at 2 to 4 hours after in situ incubation. As the radiation dose increased, the rate of PLDR fastened and the magnitude of increased surviving fraction at saturation level by PLOR also increased. In analysis of cell survival curve fitted to the linear-quadratic model, the linear inactivation coefficient $(\alpha)$ decreased largely and reached nearly to zero but the quadratic inactivation coefficient $(\beta)$ increased minimally by increment of postirradiation in situ incubation time. So PLDR mainly affected the damage expressed as $\alpha$, In the multitarget model, significant change was not obtained in $D_0\;but\;in D_q$. Therefore, shoulder region in cell survival curve was mainly affected by PLDR and terminal slope was not influenced at all. And dose-modifying factor by PLDR was relatively higher in shoulder region, that is, in low dose area below 3 Gy.

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Distribution of Cadminum Fractions in Paddy Soils and Their Relation to Cadmium Content in Brown Rice (답토양중(畓土壤中) Cadmium의 형태별(形態別) 분포(分布)와 현미중(玄米中) Cadmium 함량(含量)과의 관계연구(関係硏究))

  • Lim, Sun-Uk;Kim, Sun-Kwan
    • Korean Journal of Soil Science and Fertilizer
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    • v.16 no.1
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    • pp.28-35
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    • 1983
  • The object of this study was to investigate the distribution of Cd fractions in paddy soils in relation to some soil characteristics and to find out the relationships between soil Cd fractions and Cd content in brown rice. Thirty six soils and rice samples were collected from the paddy field adjacent to zinc mining sites at harvest time in 1981. Total Cd content of brown rice samples was analyzed. A sequential extraction procedure was used to fractionate Cd in soils into the designated forms of exchangeable, adsorbed, organically bonded, carbonate, sulfide, and residual Cd. The results obtained were as follows: 1. The distribution of Cd fractions in soil showed a wide difference depending on soil properties. As an average value it was observed that organically bonded Cd amounted 43.7%; residual Cd, 6.5%; and other fractions, 10-15%. 2. With higher soil pH, organically bonded and carbonate Cd fraction tended to be higher but exchangeable fraction lower. Other forms of Cd showed no difference with soil reaction. 3. Organically bonded fraction was positively correlated with soil organic matter content, while others except adsorbed fraction showed an adverse tendency. 4. The relation of fraction distribution to soil C E C was similar to the case of organic matter. 5. Cadmium content in brown rice showed significant possitive correlation with organically bonded Cd content (r = 0.655) and carbonate, Cd content of soil (r = 0.328) but there was no significant correlation with contents of other forms.

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Effect of Yacon (Smallanthus sonchifolius H. Robinson) Extracts on Herbicidal, Fungicidal, and Insecticidal Activities (야콘(Smallanthus sonchifolius H. Robinson) 추출물의 제초, 살균 및 살충활성 효과)

  • Yun, Young-Beom;Kim, Jin-Hwa;Jang, Se-Ji;Kim, Do-Ik;Kwon, Oh-Do;Kuk, Yong-In
    • Korean Journal of Weed Science
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    • v.32 no.2
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    • pp.98-106
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    • 2012
  • This research has been carried out to find out the highest effect on insecticidal, fungicidal and herbicidal activities in leaves, stem and tuber extracts of yacon (Smallanthus sonchifolius) and extraction methods such as water, boiling water and methanol. Characteristics of potential herbicidal components among extraction methods were investigated by solvent fractions such as hexane, chloroform, ethyl acetate, butanol, and water. Generally, methanol extract was the best on inhibition of germination rate, plant height, and root length in cucumber and barley. On the other hand, the inhibition effect on growth in cucumber and barley was the best in tuber among plant parts of yacon. Inhibition of germination rate, plant height, and root length in cucumber and barley in solvent fractions was the best in water fraction, but there were no differences in other fractions. Digitaria sanguinalis L. and Solanum nigrum L. by 5 and 10% extractions of yacon tuber were controlled by more than 70~80% and 95~100%, respectively. However, there was no inhibition effect on foliar treatment in cucumber and barley as affected by 5 and 10% extractions of yacon tuber. Mortality of green peach aphid (Myzus persicae Sulzer) was 50% at 3 days after treatment of 5% extracts of yacon leaves. Mortality of brown plant hopper (Nilaparvata lugens Stal) was only 24% in 5% extracts of stems and leaves with midrib, but was 57% in 5% extracts of leaves without midrib. There was no fungicidal effect on anthracnose (Colletotrichum truncatum), wilt disease (Fusarium oxysporum), verticillium wilt (Verticillium dahliae), bacterial blight (Xanthomonus oryzae) in 5% extracts of yacon leaves.

Change of Volume of Isoflow in Pneumoconiosis Patients with Small Opacity (소음영 진폐증 환자에서의 등기류용량(Volume of Isoflow)의 변화)

  • Oh, Sang-Yong;Kim, Jee-Won;Jung, Chang-Young;Kim, Kyung-Ah;Yun, Im-Goung
    • Tuberculosis and Respiratory Diseases
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    • v.40 no.5
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    • pp.540-547
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    • 1993
  • Backgrounds: The measurement of volume of isoflow has been considered as a sensitive test for detecting small airway diseases showing normal pulmonary function in a routine pulmonary function test. To evaluate the functions of small airway among dust exposed workers, the changes of volume of isoflow were measured and its applicability of managing early stage pneumoconiosis patients was studied. Method: The subjects were 67 male, pneumoconiosis with small opacity and FEV1>80%, FEV1/FVC>75% in spirometry and the controls were 20 male, no dust-exposed office workers. The maximal epiratory volume curves after inhalation of indoor air and $He-O_2$ gas mixtures were measured and ${\Delta}V_{max50},\;{\Delta}V_{max75},\;V_{iso}V/VC$ between the dust exposed and control workers were compaired. Results: 1) There were no significant differences between two group in ${\Delta}V_{max50}$ and ${\Delta}V_{max75}$. But the ratio of $V_{iso}V/VC$ of the subjects was siginificantly higher than that of the control (p<0.01). This study confirms that $V_{iso}V/VC$ is a very useful index in early detection of small airway dysfunction. 2) The ratio of $V_{iso}V/VC$ of the subjects was signigicantly different between only smoker group and mixed group(smoker and nonsmoker). It suggestes that smoking is an important cousative factor of small airway dysfunction. 3) As the profusion of the chest X-ray increased, the rartio of $V_{iso}V/VC$ increased, but no significant difference of $V_{iso}V/VC$ was found between categories of pneumoconiosis. The categories of pneumoconiosis and small airway dysfunction may not be related. 4) No significant relationship was established between the duration of work and the ratio of $V_{iso}V/VC$. Conclusions : It is concluded that the measurement of $V_{iso}V/VC$ is useful to detect small airway dysfuction of early stage pnuemoconiosis patents with small opacities but showing normal pulmonary function in a routine pulmonary function test.

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Minimal Invasive Surgery: A National Survey of Its Members by the Korean Association of Pediatric Surgeons (최소 침습 수술: 대한소아외과학회 회원을 대상으로 한 전국조사)

  • Kim, Dae Yeon;Kim, I.S.;Kim, H.Y.;Nam, S.H.;Park, K.W.;Park, W.H.;Park, Y.J.;Park, J.H.;Park, J.Y.;Park, J.S.;Park, J.Y.;Boo, Y.J.;Seo, J.M.;Seol, J.Y.;Oh, J.T.;Lee, N.H.;Lee, M.D.;Jang, J.H.;Jung, K.H.;Jung, S.Y.;Jung, S.E.;Jung, S.M.;Jung, E.Y.;Jung, J.H.;Cho, M.J.;Choi, K.J.;Choi, S.J.N.;Choi, S.O.;Choi, S.H.;Choi, Y.M.;Hong, J.
    • Advances in pediatric surgery
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    • v.20 no.1
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    • pp.1-6
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    • 2014
  • Minimal invasive surgery (MIS) has rapidly gained acceptance for the management of a wide variety of pediatric diseases. A questionnaire was sent to all members of the Korean Association of Pediatric Surgeons. Thirty one members (25.4%) took part in the survey that included data for the year 2012: demographic details, opinion regarding minimal invasive surgery and robotic surgery, spectrum of minimally invasive operations, and quantity of procedures. 48.4% of the respondents had more than 10 years experience, 35.5% less than 10 years experience, and 16.1 % had no experience. The respondents of the recommend MIS and perform MIS for surgical procedures are as follow; inguinal hernia (61.3%), simple appendicitis (87.1%), complicated appendicitis (80.6%), reduction of intussusceptions (83.9%), pyloromyotomy (90.3%), fundoplication (96.8%), biopsy and corrective surgery of Hirschsprung's disease (93.5%/90.3%), imperforate anus (77.4%), congenital diaphragmatic hernia (80.6%), and esophageal atresia (74.2%). The MIS procedures with more than 70% were lung resection (100%), cholecystectomy (100%), appendectomy (96.2%), ovarian torsion (86.7%), fundoplication (86.8%), hiatal hernia repair (82.6%), and splenectomy (71.4%). The MIS procedures with less than 30% were congenial diaphragmatic hernia reapir (29.6%), esophageal atresia (26.2%), correction of malroatation (24.4%), inguinal hernia repair (11.4%), anorectal malformation (6.8%), Kasai operation (3.6%).

The Influence of Food Habits on Body Stature of Children (어린이의 식습관(食習慣)이 체위(體位)에 미치는 영향(影響)에 관한 연구(硏究))

  • Lee, Mi-Suk;Mo, Su-Mi
    • Journal of Nutrition and Health
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    • v.9 no.1
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    • pp.7-15
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    • 1976
  • The Purpose of this study was to determine every possible correlation between food habits and body statures of primary school children, aged ten years old. This study was conducted from July to October of 1975. In July, prepared questionaires concerning life style, anthropometry, food preference, and food behavior were distributed through school teachers to 425 children; 219 boys and 206 girls, in the 5th grade of three elementary schools in the city of Seoul. Then, in October, when subjects had been classified into underweight/obese by statistical analysis, mothers of obese or underweight children were interviewed by the authors to determine weaning history, daily food consumption of their children, and opinions of various snacks for children. Analysis of results in terms of correlation coefficient, chisquare test and percentage calculations, are as follows: 1. Physical growth and development Boys Girls Height (cm) $134.8{\pm}5.74\;134.4{\pm}5.97$ Weight (kg) $30.0{\pm}4.27\;29.5{\pm}5.16$ Chestgirth (cm) $64.1{\pm}3.59\;63.3{\pm}3.81$ Arm circumference (cm) $18.3{\pm}1.61\;18.2{\pm}1.70$ Triceps skinfold thickness (mm) $10.9{\pm}5.13\;12.7{\pm}4.86$ Various indices of nutrition such as relative weight, relative chestgirth, $R{\ddot{o}}hrer's$ index, Kaup index, Vervaeck index were determined. 2. Food habits 1) Food $preference{\cdots}{\cdots}A$ varying number of foods were selected from 60 items were accepted. It was found that the food which children liked best was fruit and snacks were popular one. Lowest ranking among LIKED foods were from strongly flavored vegetables and organ meat. In general, girls had more food dislikes than did boys. Selected as liked foods were fruits, rice noodle soup, biscuits, and peanuts. Disliked foods were liver, green onions, onions, green pepper, mushrooms, oysters, shellfish, and pork. Items which children never ate before were liver, mushrooms, fish cake, boiled rice mixed with sorghum, mayonnaise, and fresh water firsh. Reasons which children gave for dislike were undesirable flavor and odor. 2) Food $behavior{\cdots}{\cdots}It$ was found that boys liked sweet and salty flavors more than did the girls who more often liked sour flavor. The majority of children enjoyed evening meals more than lunch and breakfast. A number of children skipped breakfast because of lack of appetite or lack of time before going to school. Snacks were the most popular food, especially among girls. Their snacking habits were formed by the encouragement of the mother, and the relieve boredom. Educational backgrounds of mothers and family economical levels of children were remarkable correlated with mothers' attitudes toward feeding of children. There were several interesting findings relating body stature to some other responses; such as that the obese child has a small number of brothers, higher birth order, higher educated mothers and higher family cultural background. It was also discovered that food perference, except for fat and oil group foods was not related to body stature. Sweet taste was liked best and pepperly taste was mostly disliked. Sour taste was popular in the group of underweight. Underweight children were more finicky, disliked snacking, and didn't get much attention from their mothers. 3) Correlation between body stature and nutrition during their infancy. The majority of children, both from obese and underweight, were breast fed as infant. Twenty five per cent of obese children and 17.4 per cent of underwight children started weaning at $1{\sim}6$ months old. The most popular supplemental food of weaning was cereal gruel for the obese group, while boiled white rice and cereal gruel were most common for the underweight group. Highly significant relationships were found between stature of parents and their children. In the obese group 47.8 per cent of fathers and 45.9 per cent of mothers were overweight; however, none of the fathers and only one mother was found to be underweight. In daily food consumption patterns, meals consisting of bread or noodle were popular in the obese group but disliked by the underweight group. The study found clear contrast in that the obese group liked meat and fish while the underweight group liked fruits and vegetables, especially kimchee. The obese children desired to eat cereal foods, milk and milk products, and fat foods while the underweight group desired to eat fruits and vegetables. Frequency of snacks per day was much greater in the obese group. Foods which mothers believed to be good for the health were carrots, cucumbers, fruits, milk, potatoes, sweet potatoes, and breads, while sweet foods such as candies, drinks. chocolate were considered not good for the teeth. Watching television was not significantly related to statures of children. Most significant relationships were found beween frequencies of family guest meals/and eating-out, and children's statures. Nutritional problems which have been considered for the malnourished children in addition to those of children who have a tendency toward obesity, must be taken into consideration in the development of proper nutrition education through the channels of regular school teaching and teaching by parents in the homes. Korean standards of anthropometric measurements for children should be revised, current measurements show much higher figures than present Korean standards.

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Effects of Samki-eum ($s\bar{a}nq\grave{i}-y\check{i}n$ ) on Freund's Complete Adjuvant-induced Arthritic Rats (Adjuvant 유발 관절염 랫트에 대한 삼기음의 효과)

  • Choi, Eun-Sill;Jang, Hong-Gyu;Kwon, O-Gon;Woo, Chang-Hoon;An, Hee-Duk
    • Journal of Korean Medicine Rehabilitation
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    • v.23 no.3
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    • pp.1-14
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    • 2013
  • Objectives The object of this study was to observe the favorable anti-arthritic effects of Samki-eum ($s\bar{a}nq\grave{i}-y\check{i}n$) on Freund's complete adjuvant (FCA)-induced arthritic Wistar rats. Methods Rheumatoid arthritis was induced by intradermal injection of FCA, and 300, 150 or 750 mg/kg of Samki-eum ($s\bar{a}nq\grave{i}-y\check{i}n$) were orally administered once a day for 14 days from 14 days after FCA treatments, and 15 mg/kg of dexamethasone was intraperitoneally administered as reference drug in this experiment. All rats were sacrificed at 14 days after continuous oral treatment of Samki-eum ($s\bar{a}nq\grave{i}-y\check{i}n$) or intraperitoneal administration of dexamethasone, and changes on the body weight, knee circumferences, gross arthritis score, inflammatory tissue prostaglandin (PG) $E_2$ levels were monitored with cartilage collagen components and glucosaminoglycans compositions - chondroitin sulphate, heparan sulphate and hyaluronic acid in the present study. Results As results of FCA treatment, classic rheumatoid arthritis featuring dramatical decreases on the body weights, cartilage collagen contents and bone glucosaminoglycans-chondroitin sulphate, heparan sulphate and hyaluronic acid contents, with increases on the knee circumferences, gross arthritis scores and inflammatory tissue $PGE_2$ levels. However, these changes from FCA-induced rheumatoid arthritis were clearly reduced by treatment of dexamethasone and both two different dosages of Samki-eum ($s\bar{a}nq\grave{i}-y\check{i}n$) 300 and 150 mg/kg in the present study. Although FCA-induced arthritis were more favorably inhibited by treatment of dexamethasone 15 mg/kg as compared with Samki-eum ($s\bar{a}nq\grave{i}-y\check{i}n$) 300 mg/kg, marked decreases of body weights were detected in dexamethasone 15 mg/kg treated rats, and Samki-eum ($s\bar{a}nq\grave{i}-y\check{i}n$) 300 mg/kg showed similar preserve effects on the cartilage glucosaminoglycan compositions in this study. Conclusions The results obtained in this study suggest that over 300 and 150 mg/kg of Samki-eum ($s\bar{a}nq\grave{i}-y\check{i}n$) showed favorable anti-arthritic effects on the FCA-induced arthritis mediated by suppression of $PGE_2$, a inflammatory mediator. However, detail mechanism studies should be conduced in future with the screening of the biological active compounds in this herb. Although overall anti-inflammatory effects Samki-eum ($s\bar{a}nq\grave{i}-y\check{i}n$) 300 mg/kg were lowered than those of dexamethasone 15 mg/kg treated rats, Samki-eum ($s\bar{a}nq\grave{i}-y\check{i}n$) 300 mg/kg treated rats showed similar preserve effects on the cartilage glucosaminoglycan compositions in this experiment.

Anti-obesity effect of EGCG and glucosamine-6-phosphate through decreased expression of genes related to adipogenesis and cell cycle arrest in 3T3-L1 adipocytes (Adipogenesis관련 유전자발현감소와 Cell Cycle Arrest를 통한 EGCG와 Glucosamine-6-Phosphate의 Anti-Obesity 효과)

  • Kim, Kkot Byeol;Jang, Seong hee
    • Journal of Nutrition and Health
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    • v.47 no.1
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    • pp.1-11
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    • 2014
  • Purpose: Several studies have proven that EGCG, the primary green tea catechin, and glucosamine-6-phosphate (PGlc) reduce triglyceride contents in 3T3-L1 adipocytes. The objective of this study is to evaluate the combination effect of EGCG and PGlc on decline of accumulated fat in differentiated 3T3-L1 adipocytes. Methods: EGCG and PGlc were administered for 6 day for differentiation of 3T3-L1 adipocytes. Cell viability was measured using the CCK assay kit. In addition, TG accumulation in culture 3T3-L1 adipocytes was investigated by Oil Red O staining. We examined the expres-sion level of several genes and proteins associated with adipogenesis and lipolysis using real-time RT-PCR and Western blot analysis. A flow cytometer Calibar was used to assess the effect of EGCG and PGluco on cell-cycle progression of differentiating 3T3-L1 cells. Results: Intracelluar lipid accumulation was significantly decreased by combination treatment with EGCG $60{\mu}M$ and PGlc $200{\mu}g/m$ compared with control and EGCG treatment alone. In addition, use of combination treatment resulted in directly decreased expression of $PPAR{\gamma}$, $C/EBP{\alpha}$, and SREBP1. In addition, it inhibited adipocyte differentiation and adipogenesis through downstream regulation of adipogenic target genes such as FAS, ACSL1, and LPL, and the inhibitory action of EGCG and PGlc was found to inhibit the mitotic clonal expansion (MCE) process as evidenced by impaired cell cycle entry into S phase and the S to G2/M phase transition of confluent cells and levels of cell cycle regulating proteins such as cyclin A and CDK2. Conclusion: Combination treatment of EGCG and PGlc inhibited adipocyte differentiation through decreased expression of genes related to adipogenesis and adipogenic and cell cycle arrest in early stage of adipocyte differentiation.

Distribution of Bacterial Decomposers in Lake Khuvsgul, Mongolia (몽골 훕스굴 호수 수층에서 유기물질 분해세균의 분포)

  • Jung, You-Jung;Jung, Da-Woon;Kim, Ju-Young;Zo, Young-Gun;Yim, Joung-Han;Lee, Hong-Kum;Ahn, Tae-Seok
    • Korean Journal of Microbiology
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    • v.45 no.2
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    • pp.119-125
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    • 2009
  • To understand the ecological function of heterotrophic bacterial community in water column of large freshwater lakes in the permafrost zone, we investigated the structure and function of bacterial community in Lake Khuvsgul, Mongolia. Species composition of overall bacterial community was analyzed by denaturing gradient gel electrophoresis (DGGE) of 16S rRNA gene fragments, and bacteria that can be cultured at 10oC were isolated and characterized. Based on the depth profile of environmental parameters, thermocline and chemocline were recognized at the 5~10 m zone of the water column. The stratified DGGE profile indicated that the discontinuity of water properties might influence the structure of bacterial community: band profiles in the 0~5 m zone were diverse with large change by depth, but the profile was relatively stable at the $\geq$10 m zone, with predominance of the band identified as Acidovorax facilis. Bacterial cultures were screened for protease, cellulase, amylase and lipase activity, and 23 isolates were selected for high activity of the hydrolytic enzymes. The isolates were identified based on their 16S rRNA gene sequences. In the surface water (zero meter depth), Acidovorax defluvii and Sphingobacterium faecium with high cellulase activity were present. Flavobacterium succinicans, Mycoplana bullata and A. facilis were stably predominant isolates at 2 m, 5 m, and $\geq$10 m depths, respectively. F. succinicans isolates showed high protease activity while M. bullata isolates showed moderate levels of protease and celluase activity. A. facilis isolates showed either cellulase or lipase activity, exclusively to each other. According to the profile of growth rates of the isolates in the temperature range of $0\sim42^{\circ}C$, the surface-zone (0~5 m) isolates were facultative psychrophiles while isolates from $\geq$10 m depth were typical mesophiles. This stratification is believed to be due to stratified availability of organic materials to the bacterial decomposers. In the water column below the chemoline, the environment is extremely oligotrophic so that the trait of rapid growth in low temperature might not be demanded by deep-lake decomposers. The stratified distribution of community composition and decomposer activity in Lake Khuvsgul implies that ecological functions of bacterial community in lakes of cold region are sharply divided by water column stratification.