• 한국환경생태학회지
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• 제27권3호
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• pp.357-368
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• 2013

본 연구는 한반도 풍혈지 식생에 대하여 ZM학파의 식물사회학적 방법을 통해 식물군락의 특성을 밝히고 풍혈지의 보전 및 관리에 필요한 기초자료를 제공을 목적으로 수행되었다. 풍혈지는 지하에 저온층이 존재하는 크고 작은 바위들의 집적지로서, 지표면에 열려진 공극으로부터 자연적인 냉풍이 불어 나와 국소적으로 저온환경이 형성된 지역이다. 63개 식생조사 자료를 이용하여 풍혈지의 식물군락을 구분한 결과, A. 굴참나무-한들고사리군락, B. 신갈나무-박달나무군락, B-1. 졸참나무-가는잎쐐기풀하위군락, B-2. 마가목-인가목조팝나무하위군락, B-3. 털댕강나무-개병풍하위군락, B-4. 전형하위군락의 2개 군락 4개 하위군락으로 구분되었다. DCCA분석 결과, 굴참나무, 쥐똥나무, 느티나무, 분꽃나무 등을 구분종으로 하는 굴참나무-한들고사리군락은 신갈나무, 쉬땅나무, 함박꽃나무, 당단풍나무, 민둥인가목 등을 구분종으로 하는 신갈나무-박달나무군락보다 온량지수와 강수량이 많은 지역과 높은 상관관계를 나타냈다. 인가목조팝나무, 마가목, 흰인가목, 산앵도나무, 산겨릅나무, 퍼진고사리, 전나무을 구분종으로 하는 마가목-인가목조팝나무하위군락과 구분종을 가지고 있지 않은 전형하위군락은 다른 하위군락에 비하여 높은 해발과 많은 강수량 지역에 분포하였으며, 당조팝나무, 털댕강나무, 개병풍, 산토끼고사리, 북분취, 일본잎갈나무 등을 구분종으로 하는 털댕강나무-개병풍하위군락은 인간활동에 의하여 일광 노출이 많은 지역에 분포하였다.

• IMMUNE NETWORK
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• 제13권5호
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• pp.213-217
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• 2013

Enterotoxigenic Bacteroides fragilis (ETBF) is a human gut commensal bacteria that causes inflammatory diarrhea and colitis. ETBF also promotes colorectal tumorigenesis in the Min mouse model. The key virulence factor is a secreted metalloprotease called B. fragilis toxin (BFT). BFT induces E-cadherin cleavage, cell rounding, activation of the ${\beta}$-catenin pathway and secretion of IL-8 in colonic epithelial cells. However, the precise mechanism by which these processes occur and how these processes are interrelated is still unclear. E-cadherin form homophilic interactions which tethers adjacent cells. Loss of E-cadherin results in detachment of adjacent cells. Prior studies have suggested that BFT induces IL-8 expression by inducing E-cadherin cleavage; cells that do not express E-cadherin do not secrete IL-8 in response to BFT. In the current study, we found that HT29/C1cells treated with dilute trypsin solution induced E-cadherin degradation and IL-8 secretion, consistent with the hypothesis that E-cadherin cleavage causes IL-8 secretion. However, physical damage to the cell monolayer did not induce IL-8 secretion. We also show that EDTA-mediated disruption of E-cadherin interactions without E-cadherin degradation was sufficient to induce IL-8 secretion. Finally, we determined that HT29/C1 cells treated with LiCl (${\beta}$-catenin activator) induced IL-8 secretion in a dose-dependent and time-dependent manner. Taken together, our results suggest that BFT induced IL-8 secretion may occur by the following process: E-cadherin cleavage, disruption of cellular interactions, activation of the ${\beta}$-catenin pathway and IL-8 expression. However, we further propose that E-cadherin cleavage per se may not be required for BFT induced IL-8 secretion.

• 대한의생명과학회지
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• 제18권4호
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• pp.362-368
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• 2012

Enterotoxigenic Bacteroides fragilis (ETBF) is an intestinal commensal bacterium implicated as a risk factor for colon cancer. The key virulence factor is a secreted toxin called B. fragilis toxin (BFT). In this study we used an in vitro bioassay to examine the prevalence of ETBF in colonic washings from patients with colorectal polyps and normal control patients. We found that 9.3% of polyp patients and 10.9% of non-polyp patients harbored ETBF, respectively. A total of nine ETBF clinical isolates were isolated and confirmed to be positive for the BFT gene by PCR analysis and the ability to induce IL-8 secretion in the colonic epithelial cell line HT29/c1. Two of the ETBF clinical strains were characterized further in vitro and in vivo. We found that the two ETBF clinical isolates induced E-cadherin cleavage in HT29/c1 cells and promoted colonic inflammation in C57BL/6 mice. Our results indicate that the prevalence of ETBF in polyp patients were similar in non-polyp patients suggesting that ETBF carriage does not positively correlate to polyp incidence.

• 대한미생물학회지
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• 제10권1호
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• pp.19-24
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• 1975

Anaerobic bacteria are the major residents of human skin and mucous membrane. The importance, as opportunistic pathogens, of anaerobic bacteria are well recognized because of more population. with decreased defense against bacterial invasion due to chemotherapy, rediation therapy, extensive surgical operation etc. are dealt at hospitals. An analysis of the anaerobe isolation results at Yonsei University Medical Center during the January 1974-May 1975 period was made and the following results were obtained. 1) From 118 patients 146 strains of anaerobes were isolated. Among these 81.3% were nonsporforming anaerobes. Most frequently isolated anaerobes were Pc. asaccharolyticus, Ps. anaerobius, Ps. intermedius, B. fragilis and Cl. perfringens. 2) Anaerobes were frequently isolated from wound, female genital, intraabdominal, and pleuropulmonary specimens. Fewer anaerobes were isolated from blood, spinal fluid and liver specimens. 3) The ratio of anaerobe isolation to total bacteria isolation were; liver 66.7%, intraabdominal 33.3%, pleuropulmonary 28.9%, spinal fluid 5.0% and blood 4.2%. 4) Among the 118 anaerobe isolated patients, 48.3% yielded anaerobes only and rest of them yielded anaerobes together with aerobes. 5) Most of the gram-positive anaerobes were susceptible to the antibiotics tested. Exception was to tetracycline to which appreciable number showed resistance. It was noteworthy that only 48% of B. fragilis was susceptible to tetracycline.

• Journal of Microbiology and Biotechnology
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• 제10권4호
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• pp.514-517
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• 2000

Abstracts Six shikonin metabolites were obtained from human intestinal bacteria, Bacteriodes fragilis subsp. thetaotus. following biotransformation. The transformation of shikonin (1) was performed anaerobically for 3 day at $37^{\circ}C$ in thc bacterial suspension of B. Fagilis which was cultured overnight in GAM broth. The incubation mixture \vas extracted with EtGAc Lo give a dark-brown residue. The residue was apphed to a silica gel column, which was eluted successively with hexane (Fr. A), $CHCl_3$ (Fr. B), and $CHCl_3$:MeOH (9:I) (Fr. C). Six metabolites. Fr.A (2 and 3), Fr. B (6 and 7), and Fr. C (4 and 5) were isolated by repeated silica gel column chromatography, preparatlVe TLC, followed by Sephadex LH-20. In vitro cytotoxicities were tested against human tumor cell lines; PC-3 (prostate), ACHN (renal), A549 (lung), SW620 (colon), KS62 (leukemia), and Du145 (prostate). The shikonin metabolites 2. 4, 5, and 6 showed weaker cytotoxicity than the parenL shikonin (1). whereas shikonin monomenc metabolite 3 ($ED_{50}{\;}O.44-{\;}1.22{\;}\mu\textrm{g}/ml$) and dimeric metabolite 7 ($ED_{50}{\;}O.48-{\;}2.35{\;}\mu\textrm{g}/ml$) exhibited stronger activities compared with adriamycin, which was used as the positive control.ontrol.

• Journal of Microbiology and Biotechnology
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• 제5권1호
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• pp.6-13
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• 1995

A gene coding for the $\beta$-galactosidase (lactase) of Kluyveromyces tragilis UCD 55-55 was isolated by complementation in Escherichia coli YMC9. From the plasmid library made from Sau3A-digested chromosomal DNA, one positive clone was selected. The cloned gene for $\beta$-galactosidase was on 7.3 kilobase pair DNA fragment, and a slightly low level of $\beta$-galactosidase enzyme activity was detecied in E. coli. It was also confirmed that the cloned gene comes from K. tragilis by DNA-DNA hybridization and immunochemical blotting experiments. In order to construct a new yeast strain having the metabolic ability for lactose, the cloned gene for K. tragilis $\beta$-galactosidase was inserted in yeast vector YEp24 and YRp17, and transformed into Saccharomyces cerevisiae YNN27 and Ml-2B. The yeast transformants showed the nearly the same $\beta$-galactosidase productivity as level of K. tragilis when uninduced, but these could not utilize lactose as a sole carbon source, presumably due to the lack of lactose transport system. Nevertheless, a slightly higher ethanol productivity was achieved by these transformants than S. cerevisiae or K. tragilis, in the medium containing glucose and lactose.

• 대한미생물학회지
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• 제35권5_6호
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• pp.350-350
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• 2000

• 대한미생물학회지
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• 제20권1호
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• pp.35-44
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• 1985

Isolation and identification of anaerobic bacteria from blood cultures are still technically demanding procedures. Recently, with the use of gas liquid chromatography, the accuracy of identification is much improved. However, there has never been a satisfactory data analysis on anaerobic bacteremia in Korea. The authors evaluated both the clinical and the bacteriological data of 129 anaerobic bacteremias found at the Yonsei Medical Center during the period of 1973 to 1984. The most frequently isolated anaerobic bacteria were Bacteroides (52.7%), among which the major species was B. fragilis (38.7%). Incidence of anaerobic bacteremia by sex was 57% in male and 43% in female. Mortality was higg in groups below 1-year old and above 50-year old. The cause of death seemed closely correlated with the patient's age, general condition and the severity of the underlying disease. Various neoplasms were the most common (20%) underlying diseases predisposing the anaerobic bacteremia. Biliary tract was considered the most frequent route of infection in anaerobic bacteremia. The frequent clinical signs in anaerobic bacteremia were fever (65%), followed by liver function abnormality (29%), jaundice (20%) and hypotention(18%). When analysis of positive rate of blood culture was made on the patients from whom 4 cultures were done within 24 hours, it was found that 33% of the samples were positive. Isolation rate of anaerobic bacteria in thioglycollate medium was 83.8%, while it was 44% in Tryptic soy broth. Among the anaerobic bacteremia, 25.4% were polymicrobial infections with aerobic bacteria (92.5%), such as E. coli(33.3%). From these studies, it is concluded that B. fragilis is the most important causative organism in anaerobic bacteremia, with high fatality, particularly in those who have underlying diseases. The ports of entry are mainly biliary, gastrointestinal and female genital tract. Fever is the most frequent clinical sign. Single blood culture is not sufficient to detect all anaerobic bacteremia, therefore more cultures with optimal time interval are needed. The incidence of polymicrobial infection in anaerobic bacteremia is higher than that in overall bacteremia.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.314.1-314.1
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• 2002

Bacterial ${\beta}$-lactamases provide resistance to ${\beta}$-lactams by hydrolyzing the ${\beta}$-lactam bond, On the basis of their catalytic mechanisms. ${\beta}$-lactamases are divided into two major groups. Class A. C and D which belong to the first group require serine in the active site and class B which is the second group require Zn(II) for their activity. Among class B enzymes, Bacteroides fragilis ${\beta}$-lactamase (CcrA enzyme) require two Zn(II) ions per monomer for maximal enzymatic activities. (omitted)

• Journal of Microbiology and Biotechnology
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• 제30권11호
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• pp.1640-1650
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• 2020

Colorectal cancer (CRC) is the leading cause of common malignant neoplasm worldwide. Many studies have analyzed compositions of gut microbiota associated with various diseases such as inflammatory bowel diseases (IBD) and colon cancer. One of the most representative bacteria involved in CRC is enterotoxigenic Bacteroides fragilis (ETBF), a species belonging to phylum Bacteroidetes. We used ETBF colonized mice with azoxymethane (AOM)/dextran sulphate sodium (DSS) and zerumbone, a compound with anti-bacterial effect, to determine whether zerumbone could restore intestinal microbiota composition. Four experimental groups of mice were used: sham, ETBF colonized AOM/DSS group, ETBF colonized AOM/DSS group zerumbone 60 mg kg-1 (ETBF/AOM/DSS + Z (60)), and only zerumbone (60 mg kg^-1)-treated group. We performed reversible dye terminators-based analysis of 16S rRNA gene region V3-V4 for group comparison. Microbiota compositions of ETBF/AOM/DSS + Z (60) group and ETBF colonized AOM/DSS group not given zerumbone were significantly different. There were more Bacteroides in ETBF/AOM/DSS + Z (60) group than those in ETBF colonized AOM/DSS group, suggesting that B. fragilis could be a normal flora activated by zerumbone. In addition, based on linear discriminant analysis of effect size (LEfSe) analysis, microbial diversity decreased significantly in the ETBF colonized AOM/DSS group. However, after given zerumbone, the taxonomic relative abundance was increased. These findings suggest that zerumbone not only influenced the microbial diversity and richness, but also could be helpful for enhancing the balance of gut microbial composition. In this work, we demonstrate that zerumbone could restore the composition of intestinal microbiota.