• Korean Journal of Microbiology
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• v.55 no.3
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• pp.248-257
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• 2019

In this study, we isolated about 70 bacterial strains from terrestrial and marine environments in Jeju island, and finally, total 21 strains were obtained based on the 16S ribosomal RNA gene sequence analysis. These isolated strains were classified into 16 genera of 5 classes and were identified as an unrecorded species in the Republic of Korea. As a result of the substrate utilization and capability for polymer degradation, the physiological phenotypes for acid resistance and halophilic bacteria were observed to be distinct from each other, except for some acid resistance strains. This study might provide basic information on utilization for indigenous microorganisms.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.47 no.2
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• pp.171-178
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• 2021

In this study, exosomal-like nano-vesicles derived from probiotics were isolated and various physiological activities were evaluated on the skin. This study show that Lactococcus lactis subsp. lactis (LL) are incubated, and then isolated LL derived exosomal nanovesicles (LVs) at the range of 70 ~ 200 nm by high-pressure homogenizer and ultrafiltration. The vesicle numbers were an average of 1.81 × 10¹¹ particles/mL. This study finds out the bacterial nanovesicles' beneficial effect on the skin. Fibrillin (FBN1) gene expression increased by 23% in fibroblast cells. Fibronectin (FN1) and filaggrin (FLG) gene expression increased by 65% and 400% in keratinocytes. We could see that cornified envelope (CE) formation ability was increased by 30% compared to the control group. Furthermore, collagen type I alpha 1 (COL1A1) protein expression increased by 83% compared to the UV-irradiated control group. These results suggest that LVs could help skin barrier improvement and used as an ingredient for cosmetics or pharmaceuticals.

• Composites Research
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• v.35 no.3
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• pp.153-160
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• 2022

Cellulose nanofibrils (CNF) based on wood pulp fibers are gained much attention as part of biocompatible hydrogels for biomedical applications such as tissue engineering scaffolds, biomedicine, and drug carrier. However, CNF hydrogels have relatively poor mechanical properties, impeding their applications requiring high mechanical integrity. In this work, we prepare 2,2,6,6-tetramethylipiperidin-oxyl (TEMPO) oxidated cellulose nanofibrils hydrogels mediated with metal cations, which form the metal-carboxylate coordination bonds for enhanced mechanical strength and toughness. We conduct the large amplitude oscillatory shear (LAOS) test and Live/dead cell assay for obtaining nonlinear viscoelastic parameters and cell viability, respectively. In particular, the cell proliferation and viability change depending on the type of metal salt, which also affected the rheological properties of the hydrogels.

• Korean Chemical Engineering Research
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• v.61 no.4
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• pp.619-626
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• 2023

Primary and secondary amine-based sorbents were synthesized to investigate the operation capacity for the carbon dioxide separation TSA process. (3-Aminopropyl) triethoxysilane was used as a primary amine precursor as a crosslinking agent to synthesize a secondary amine precursor in which amine groups were crosslinked with a crosslinking agent. Carbon dioxide absorbed by primary amines is completely separated above 170 ℃. The working capacity of the primary amine absorbent was less than 2% when regenerated at 130℃. The secondary amine absorbent has a higher carbon dioxide separation capacity at a lower regeneration temperature than the primary amine absorbent. The secondary amine absorbent could predict process operation performance of about 6.5% with 2% carbon dioxide absorption and 100% carbon dioxide regeneration conditions. Therefore, it was found that the working capacity of the secondary amine absorbent was higher than that of the primary amine.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2023.04a
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• pp.24-24
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• 2023

본 실험은 한반도 극지 고산식물인 진퍼리꽃나무[Chamaedaphne calyculata (L.) Moench] 종자의 형태적 특성을 조사하고 변온조건과 저온처리 및 GA3 처리가 발아에 미치는 영향을 구명하고자 수행하였다. 진퍼리꽃나무 종자는 국립수목원 전시원에서 채종 후 4℃에 저온건조 저장하였으며 전자현미경(DVM6, Leica Microsystems GmbH, Wetzlar, Germany)을 이용하여 종자와 배의 길이를 측정하였다. 2022년 3월에 growth chamber 내에서 32일간 15/6℃, 25/15℃ 변온조건하에 배양하였으며, 저온층적처리(0, 40일) 및 GA3 처리(0/500/1,000mg·L^-1) 처리에 따른 발아 특성을 구명하였다. 진퍼리꽃나무 종자의 최종발아율(FGP)은 25/15℃ GA3 1000mg·L^-1 처리에서 42.2%로 가장 높게 조사되었다. 평균발아일수(MGT)는 15/6℃ 저온층적 처리에서 22.3일로 가장 높았으며, 대부분 15/6℃ 변온조건에서 25/15℃ 변온조건보다 6∼8일 높았다. 최종발아일의 평균은 약 12일로 확인되었다. 저온 층적처리 결과, 최종발아율(FGP)은 온도조건 25/15℃, 15/6℃에서 각각 32.2%와 11.1%를 보여 무처리구에서 조사된 24.4%와 10.0%보다 각각 7.8%, 1.1% 높게 나타났다. 호르몬처리 결과, 동일한 발아조건에서 GA3 500mg·L^-1 처리보다 1000mg·L^-1 처리에서 더 높은 발아율을 보였다. GA3 1000mg·L^-1 처리에서의 최종발아율(FGP)DKSH은 25/15℃, 15/6℃ 각각 42.2%와 30.0%를 보여 무처리구 보다 각각 17.8%, 20% 높게 나타났다.

• Tuberculosis and Respiratory Diseases
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• v.51 no.3
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• pp.224-231
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• 2001

Purpose : An anthracofibrosis(AF), dark multiple anthracotic pigmentations combined with narrowing and obstruction of bronchi, was reported to be strongly related with past and active pulmonary tuberculosis. This study was performed to determine whether anti-tuberculous regiemens would be helpful in patients with anthracofibrosis who failed to demonstrate the evidences of pulmonary tuberculosis. Methods : Twenty-two patients with multiple anthracotic pigmentations in bronchial mucosa with luminal narrowing were enrolled in this study. The bacteriological and histological findings for Mycobacterium tuberculosis was reviwed in each patients. They are composed of 8 males and 14 females ranging from 55 to 85 years old in age. Results: The most common symptoms were coughing(73%, 16/22), followed by sputum(41%, 9/22), dyspnea on exertion(32%, 7/22), and hemoptysis(27%, 6/22). The evidence of pulmonary tuberculosis, defined by positive AFB smear or culture of Mycobacterium tuberculosis from sputum or bronchial washing fluid or histological findings of granuloma with caseous necrosis, were found in eleven patients(50%) and the others has showed no evidences. Among 11 patients without pulmonary tuberculosis, only one patient showed the evidences of pulmonary tuberculosis after 16 months, and the 8 patients still showed no evidence of pulmonary tuberculosis during follow-up periods of ranging from 8 months to 60 months. Conclusions : Beause the anthracofibrosis is closely related to tuberculosis, it needs to find out extensively the evidences of tuberculosis in patients with anthracofibrosis. Chemotherapy for tuberculosis should be administrated only with confirmation of tuberculosis on bacteriologic study.

• Applied Biological Chemistry
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• v.50 no.4
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• pp.268-275
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• 2007

Diversity of the mud flat microbial population in Suncheon Bay was investigated by studying extracellular enzyme activities and 16S rDNA sequences. Four culturable bacterial strains with CMCase, xylanase and protease activities were isolated from the wetland and the mud flat. All the strains produced more xylanase activity than CMCase or protease activity, and the properties of the isolate enzymes from the wetland were similar to those from the mud flat. About 2,000 clones were obtained with the 16S rDNA amplified from the metagenomic DNA isolated from the mud samples. Based on the restriction pattern(s), seventeen clones were selected for base sequence analysis. Of the 17 clones, only 35% (6 clones) were found to be cultured strains and 65% (11 clones) to be uncultured strains. The similarities in the base sequences of the clones ranged from 91.0% to 99.9% with an average similarity of 97.3%. The clones could be divided into 7 groups, Proteobacteria (9 clones, 52.9%), Firmicutes (3 clones, 17.6%), Bacteroidetes (1 clone), Flavobacteria (1 clone), Verrucomicrobia (1 clone), Acidobacteria (1 clone), and Chloroflexi (1 clone). Most of the Proteobacteria clones were gamma Proteobacteria associated with oxidation-reduction of sulfur.

• Tuberculosis and Respiratory Diseases
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• v.54 no.3
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• pp.295-303
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• 2003

Backgroung : The incidence of penicillin-resistant streptococcus pneumoniae(PRSP) accounts for almost 70% of all pneumococcal pneumonia cases in Korea. It is still unclear as to whether the efficacy of penicillin or equally active beta-lactam agents is compromised in PRSP pneumonia. This study investigated the prevalence of PRSP in community-acquired pneumonia and its clinical course. Methods : A total of 42 patients with community-acquired pneumococcal pneumonia were evaluated from July 1999 to May 2001. The cultured strains of Streptococcus pneumoniae were divided into susceptible, intermediately resistant, and resistant strains by an E-test, and the effect of the clinical course was investigated. Results : From a total of 42 patients, 22 (52.4%) patients had an intermediate resistance (MIC $0.1-1{\mu}g/m{\ell}$) and six (14.3%) showed a high resistance ($MIC{\geq}2.0{\mu}g/m{\ell}$) with current penicillin susceptibility categories. However, according to the classification of the DRSPTWG (Drug Resistant Streptococcus pneumoniae Therapeutic Working Group), there were 11 cases (26.2%) of intermediate resistance and no case of high resistance. Under empirical antimicrobial treatment, there was no difference in the clinical outcome between the penicillin susceptible and resistant group. Conclusion : The clinical outcome of PRSP pneumonia with empirical therapy was acceptable. These results suggest that the current MIC breakpoint for penicillin resistance in Streptococcus pneumoniae has been set at a very low level and penicillin resistance according to the NCCLS classification does not significantly influence the outcome of the empirical treatment for pneumococcal pneumonia.

• Tuberculosis and Respiratory Diseases
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• v.50 no.3
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• pp.334-342
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• 2001

Background : RpoB gene mutations have been found in about 96-98% of rifampicin (RMP)-resistant Mycobacterium tuberculosis. Recent reports confirm that the in laboratory settings a rpoB gene mutation can be used as a surrogate marker for multi-drug resistant tuberculosis. However, its usefulness in clinical applications has not been evaluated. This study was performed to confirm whether mutation analysis of the rpoB gene of M. tuberculosis is useful in clinical settings. Methods : The medical records of 33 patients in whom rpoB gene analysis was conducted using an INNOLiPA Rif. TB assay (LiPA) from June, 1998, to July, 2000, at the Asan Medical Center were retrospectively reviewed in 33 patients. The clinical characteristics in addition to the drug susceptibility and LiPA results were analyzed. The drug susceptibility test was considered as a gold standard method for M. tuberculosis susceptibility and these results were compared with those of the rpoB gene study and sequencing analysis. Sequencing analysis of the rpoB gene was done in cases where there was a discrepancy between the results of the drug susceptibility an d rpoB gene study. Results : The mean age and sex ratio was $42{\pm}18$, and 24:9 (M:F), respectively. There were 19 RMP susceptible (58%) and 14 RMP-resistant cases (42%) according to the rpoB gene study. The mean time from the request to reporting the results of the rpoB gene study was $5.2{\pm}2.6$ days. The mean gap from reporting the rpoB gene study to reporting the susceptibility was $56{\pm}35$ days. Twenty-eight cases (85%) showed identical results compared with the drug susceptibility results, whereas five cases (15%) showed contradictory results. When compared with the sequencing analysis, of the five cases that showed contradictory results, two had LiP A analysis errors and the remaining three were identical to the sequencing results. The rpoB gene study was of assistance in choosing the appropriate drugs in 28 cases (85%). Conclusions : An rpoB gene study using an LiP A assay was useful in rapidly diagnosing RMP-resistant tuberculosis, which enabled a proper choice of the appropriate drugs in clinical practices. However, an LiPA assay always should be performed in conjunction with microscopy, culture, and susceptibility tests.

• Research in Plant Disease
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• v.17 no.1
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• pp.38-43
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• 2011

Almost 10~30% of vegetables were discarded by the spoilage from farms to tables. After harvest, vegetables are often spoiled by a wide variety of microorganisms including many bacterial and fungal species. This investigation was conducted to extent the knowledge of relationship the spoilage of vegetables and the diversity of microbes. The total aerobic bacterial numbers in fresh lettuce, perilla leaf, and chicory were $2.6{\sim}2.7{\times}10^6$, $4.6{\times}10^5$, $1.2{\times}10^6\;CFU/g$ of fresh weight, respectively. The most common bacterial species were Pseudomonas spp., Alysiella spp., and Burkholderia spp., and other 18 more genera were involved in. After one week of incubation of those vegetables at $28^{\circ}C$, the microbial diversity had been changed. The total aerobic bacterial numbers increased to $1.1{\sim}4.6{\times}10^8$, $4.9{\times}10^7$, and $7.6{\times}10^8\;CFU/g$ of fresh weight for lettuce, perilla leaf, and chicory that is about $10^2$ times increased bacterial numbers than that before spoilage. However, the diversity of microbes isolated had been simplified and fewer bacterial species had been isolated. The most bacterial population (~48%) was taken up by Pseudomonas spp., and followed by Arthrobacter spp. and Bacillus spp. The spoilage activity of individual bacterial isolates had been tested using axenic lettuce plants. Among tested isolates, Pseudomonas fluorescence and Pantoea agglomerans caused severe spoilage on lettuce.