• 한국환경농학회지
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• 제27권1호
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• pp.50-59
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• 2008

A greenhouse experiment was conducted to investigate the role of the arbuscular mycorrhizal(AM) fungus, Glomus mosseae(BEG 107) in enhancing growth and arsenic(As) and phosphorus(P) uptake of white clover(Trifolium repens) and evening primrose(Oenothera odorata) in soil collected from a gold mine having concentrations of 381.6 mg total As $kg^{-1}$ and 20.5 mg available As $kg^{-1}$. Trifolium repens and O. odorata are widely distributed on abandoned metalliferous mines in Korea. The percent root colonization by the AM fungus was 55.9% and 62.3% in T. repens and O. odorata, respectively, whereas no root colonization was detected in control plants grown in a sterile medium. The shoot dry weight of T. repens and O. odorata was increased by 323 and 117% in the AM plants compared to non-mycorrhizal(NAM) plants, respectively. The root dry weight increased up to 24% in T. repens and 70% in O. odorata following AM colonization compared to control plants. Mycorrhizal colonization increased the accumulation of As in the root tissues of T. repens and O. odorata by 99.7 and 91.7% compared to the NAM plants, respectively. The total uptake of P following AM colonization increased by 50% in T. repens and 70% in O. odorata, whereas the P concentration was higher in NAM plants than in the AM plants. Colonization with AM fungi increased the As resistance of the host plants to As toxicity by augmenting the yield of dry matter and increasing the total P uptake. Hence, the application of an AM fungus can effectively improve the phytoremediation capability of T. repens and O. odorata in As-contaminated soil.

• Journal of Korean Biological Nursing Science
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• 제25권4호
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• pp.285-294
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• 2023

Purpose: This study aimed to identify the colonization rate of carbapenem-resistant Enterobacteriaceae (CRE), the characteristics of CRE isolates, and risk factors for CRE colonization in patients transferred to the general wards of a small/medium-sized hospital. Methods: This retrospective study was conducted on patients who underwent CRE culture tests within 24 hours of admission among patients transferred to a small/medium-sized hospital. Forty-seven patients confirmed as positive for CRE were classified as belonging to the patient group. For the control group, 235 patients (five times the number of the patient group) were matched by sex, age, and diagnosis, and then selected at random. Data were analyzed using descriptive analysis and multiple logistic regression analysis. Results: The CRE colonization rate was 5% (47 out of 933 patients), and Klebsiella pneumoniae (68.0%) was the most common isolate of CRE. The positivity rate of carbapenemase-producing Enterobacteriaceae was 61.7%. The risk factors for CRE colonization included renal disease (odds ratio [OR]=4.93; 95% confidence interval [CI], 1.49-16.31), heart disease (OR=3.86; 95% CI, 1.35-11.01), indwelling urinary catheters (OR=4.43; 95% CI, 1.59-12.36), and cephalosporin antibiotic use (OR=8.57; 95% CI, 1.23-59.60). Conclusion: Having a comorbid renal or cardiac disease, an indwelling urinary catheter, or a history of exposure to cephalosporin antibiotics could be classified as risk factors for CRE colonization in patients transferred to small and medium-size hospitals. It is necessary to perform active infection control through proactive CRE culture testing of patients with risk factors.

• 한국토양비료학회지
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• 제33권4호
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• pp.283-291
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• 2000

공생균근은 인산을 비롯한 무기영양소의 흡수 촉진을 통하여 작물의 생육을 증대시킬 수 있으며, 토양 중의 유효 인산함량은 이러한 공생균근의 형성에 크게 영향을 미친다. 일반적으로 유효인산 함량이 증가할수록 공생균근 형성율은 낮아 지는데, 제주도 화산회 토양에서 인산 시용 수준을 달리하여 탱자 유묘의 공생균근 형성율과 인산 등 무기영양소의 흡수관계를 조사하였다. 비경작지 화산회 토양에 중과석과 복합비료로 40,573, 1,106, 1,373, $1,640mg\;P\;kg^{-1}$ 수준으로 인산을 처리하였으며 탱자 유묘를 5개월 동안 온실에서 재배하였다. 공생균근 형성율은 인산 시용 수준이 증가할수록 감소하였으며, 토양 유효 인산 함량이 $100mg\;P\;kg^{-1}$ 이상인 조건에서는 공생균근의 형성은 크게 저해되었다. 탱자 유묘의 인산 흡수와 공생균근 형성을 사이에는 토양 중의 유효 인산 함량이 낮을수록 높은 상관관계를 보였으며, 공생균근에 의한 인산 흡수 촉진 효과 또한 유효 인산 함량이 낮을수록 증가하였다. 인산 외 질소, 칼륨, 칼슘, 마그네슘, 아연 등의 무기영양소 흡수 또한 공생균근에 의해 촉진되는 것으로 나타났으며, 구리에 대한 흡수 촉진 효과는 인정되지 않았다.

• 한국축산식품학회지
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• 제33권4호
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• pp.522-530
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• 2013

Probiotic 기능성이 우수한 유산균을 선발하기 위하여 9개월 미만의 모유수유아로부터 100종의 Lactobacillus균을 분리하였다. C. elegans를 이용한 in vivo 실험으로 장내 우점능을 검사하여 L. rhamnosus GG와 비교했을 때 다른 균주들보다 상대적으로 장환경에 대하여 우수한 우점특성을 갖는 probiotic 유산균주 9종을 선발하였다. Mucin을 이용한 in vitro 부착능력 검토결과, L. rhamnosus GG대비 90% 이상의 부착능을 보였으며, pH 2.5에서의 내산성 및 0.5% oxgall을 함유한 내담즙성에서 각각 97% 이상과 99% 이상의 높은 생존율을 나타냈다. 또, 81% 이상의 높은 콜레스테롤 저해능과 다양한 prebiotics 이용가능성을 확인하였고 최종적으로 L. rhamnosus 4종, L. plantarum 5종인 것으로 동정되었다. 이상의 결과로부터 in vivo 실험을 통해 우선 선발한 균주들이 프로바이오틱스 균주로서 요구되는 조건을 우수하게 충족시킨다는 것을 알 수 있었으며, 따라서 in vivo 모델로서 C. elegans을 이용한 장내우점능력 검토는 내산성, 내담즙성, 콜레스테롤 저하, 그리고 prebiotic 기질 이용능 등의 고기능성의 probiotic 균주 선발에 직접적으로 이용할 수 있을 것으로 기대된다.

• The Plant Pathology Journal
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• 제27권3호
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• pp.272-279
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• 2011

Root colonization of Arabidopsis thaliana with Pseudomonas chlororaphis O6 induces systemic tolerance against diverse pathogens, as well as drought and salt stresses. In this study, we demonstrated that 11 genes in the leaves were up-regulated, and 5 genes were down-regulated as the result of three- to five-days root colonization by P. chlororaphis O6. The identified priming genes were involved in cell signaling, transcription, protein synthesis, and degradation. In addition, expression of selected priming genes were induced in P. chlororaphis O6-colonized plants subjected to water withholding. Genes encoding defense proteins in signaling pathways regulated by jasmonic acid and ethylene, such as VSP1 and PDF1.2, were additional genes with enhanced expression in the P. chlororaphis O6-colonized plants. This study indicated that the expression of priming genes, as well as genes involved in jasmonic acid- and ethylene-regulated genes may play an important role in the systemic induction of both abiotic and biotic stress due to root colonization by P. chlororaphis O6.

• Journal of Microbiology
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• 제45권1호
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• pp.11-14
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• 2007

Over the last few years, the endophytic bacterial community associated with citrus has been studied as an important component interacting with Xylella fastidiosa, the causal agent of citrus variegated chlorosis(CVC). This bacterium may also colonize some model plants, such as Catharanthus roseus and Nicotiana clevelandii. In the present study, we compared the endophytic colonization of Citrus sinensis and Catharanthus rose us using the endophytic bacteria Klebsiella pneumoniae. We chose an appropriate strain, K. pneumoniae 342 (Kp342), labeled with the GFP gene. This strain was inoculated onto seedlings of C. sinensis and C. roseus. The isolation frequency was determined one week after the inoculation and the endophytic colonization of K. pneumoniae was observed using fluorescence microscopy. Although the endophytic bacterium was more frequently isolated from C. roseus than from C. sinensis, the colonization profiles for both host plants were similar, suggesting that C. roseus could be used as a model plant to study the interaction between endophytic bacteria and X. fastidiosa.

• 대한치과보철학회지
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• 제24권1호
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• pp.91-103
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• 1986

Using imprint cultures and epithelial smears, the density and prevalence of colonization of oral mucosal sites and denture surfaces by Candida albicans has been determined in 28 healthy dentate subjects and 20 denture wearers. With questionnaire, oral and denture examination, the relationship between the carrier rates and several factors; DMFT, oral hygiene index, salivary pH & denture plaque score were studied. But these factors have not significant relationship to the carrier rates. Imprint culture appears to be sensitive technique for detecting candidal carriers and be useful for distinguishing between the healthy carrier state and candidal infection. Cigarette smokers had a significantly increased carrier state (P<0.05) compared with nonsmoker in male dentate subjects. Female were more frequent carriers than male in dentate and denture group, but these differences were not significant. In denture wearers, there was a higher density and frequency of candidal colonization of all mucosal sites sampled, compared with that of healthy dentate group especially anterior palate and posterior palate showed highly significant differences in frequency of candidal colonization (P<0.05). The distribution of Candida albicans is not uniform throughout the mouth. The tongue in the healthy dentate subjects and the impression surfaces of upper dentures are the primary oral reservoirs for the fungus. Overnight wearing of dentures was associated with increased density and frequency of candidal colonization and density.

• 대한의생명과학회지
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• 제10권3호
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• pp.309-315
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• 2004

Methicillin resistant Staphylococcus aureus (MRSA) is one of the most common nosocomial pathogens. Many hospitals are facing the problems which they have to use expensive antibiotics and suffer from long term hospital study of patients due to MRSA. This study is to survey MRSA nasal colonization of patients and doctors, and to investigate the mode of transmission of MRSA by pulsed field gel electrophoresis (PFGE) and then use these data to prevent further spread of cross infection and reduce nosocomial infection. Subjects of this study were 201 patients with MRSA infection at an university hospital in Busan from Sept. 1997 to Aug. 1998. Bacterial genotypes of MRSA strains isolated from nares and wound of patients (14 cases) and nares of doctors (8 cases) were analyzed by PFGE. Nasal cultures of 20 I patients for detecting nasal colonization of MRSA were performed and incidence rate of nasal colonization was 40％ (80/201). Among 201 patients MRSA were acquired from hospital in 140 (70％) patients and were acquired from community 61 (30％) patients. Among 14 pairs of MRSA from colonized or infected sites and anterior nares, DNA patterns of 10 pairs (71.4％) were equal. 86％ (12/14) MRSA strains isolated from patients and 12.5％ (1/8) MRSA strains isolated from doctors show same pattern. DNA patterns were changed in some doctors after nasal oint. Treatment. It could be inferred that the most sources of MRSA in hospital are the endemically existing MRSA. Therefore, we believe that it would be necessary to control MRSA nasal colonization of the patients and the related medical teams to reduce the medical cost and to improve the efficacy of medical cares.

• ALGAE
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• 제19권2호
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• pp.107-114
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• 2004

Patterns of epilithic algal colonization on artificial substrata (unglazed ceramic tiles) were investigated from 23rd April to 3rd July 1999 at weekly intervals over a 10 weeks period outside and inside the mesocosm in Togyo reservoir within the Civilian Passage Restriction Line near Demilitarized Zone (DMZ) in Korea. The highest standing crops of epilithic algae was 1,798$\cdot$10³ cells$\cdot$$cm^{-2}$ outside the mesocosm on 26th June and also inside the mesocosm those was 2,391$\cdot$10³ cells$\cdot$$cm^{-2}$ on 26th June, 9 weeks after the experiment began. The dominants outside the mesocosm were Achnanthes minutissima, Navicula bicephala, Oscillatoria angusta, Synedra delicastissima, S. tenuissima, S. ulna v. danica and Tabellaria flocculosa, and those inside the mesocosm were Achnanthes minitissima, Coenochloris polycocca, Fragilaria crotonenesis, Peridinium cinctum, Synedra delicatissima, Tabellaria flocculosa and Ulothrix subtilissima. Diatoms were most abundant and Achnanthes minutissima was the most important species colonizing on the tiles. Chlorophyll-a content was highest value of 5.4 mg$\cdot$$m^{-2}$ on 19th June after 8 weeks growth outside the mesocosm and was 24.4 mg$\cdot$$m^{-2}$ on 26th June, 9 weeks after the experiment began on tiles inside the mesocosm. It was also shown that unglazed ceramic tiles were a more suitable substratum for colonization than the glass slides. Consequently the substratum selection plays an important role in the colonization by the epilithic algal community.

• The Plant Pathology Journal
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• 제28권3호
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• pp.270-281
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• 2012

The bacteria B1-9 that was isolated from the rhizosphere of the green onion could promote growth of pepper, cucumber, tomato, and melon plants. In particular, pepper yield after B1-9 treatment on the seedling was increased about 3 times higher than that of control plants in a field experiment. Partial 16S rDNA sequences revealed that B1-9 belongs to the genus Pantoea ananatis. Pathogenecity tests showed non-pathogenic on kimchi cabbage, carrot, and onion. The functional characterization study demonstrated B1-9's ability to function in phosphate solubilization, sulfur oxidation, nitrogen fixation, and indole-3-acetic acid production. To trace colonization patterns of B1-9 in pepper plant tissues, we used $DRAQ5^{TM}$ fluorescent dye, which stains the DNAs of bacteria and plant cells. A large number of B1-9 cells were found on the surfaces of roots and stems as well as in guard cells. Furthermore, several colonized B1-9 cells resided in inner cortical plant cells. Treatment of rhizosphere regions with strain B1-9 can result in efficient colonization of plants and promote plant growth from the seedling to mature plant stage. In summary, strain B1-9 can be successfully applied in the pepper plantation because of its high colonization capacity in plant tissues, as well as properties that promote efficient plant growth.