• Journal of Microbiology and Biotechnology
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• 제11권1호
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• pp.17-20
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• 2001

Whole-cell attachment by covalent linkage, thereby simulating natural and specific attachments, improves the osmotolerance of Saccharomyces cerevisiae cells. The enhanced osmoresistance is correlated with a decrease in the intercellular concentration of trehalose and accompanied by membrane compositional changed. The results obtained indicate that yeast cell-support (physical) contact is sensed and responded to.

• Journal of Microbiology and Biotechnology
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• 제24권9호
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• pp.1216-1225
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• 2014

Biofilm-related infections of Candida albicans are a frequent cause of morbidity and mortality in hospitalized patients, especially those with immunocompromised status. Options of the antifungal drugs available for successful treatment of drug-resistant biofilms are very few, and as such, new strategies need to be explored against them. The aim of this study was to evaluate the efficacy of phenylpropanoids of plant origin against planktonic cells, important virulence factors, and biofilm forms of C. albicans. Standard susceptibility testing protocol was used to evaluate the activities of 13 phenylpropanoids against planktonic growth. Their effects on adhesion and yeast-to-hyphae morphogenesis were studied in microplate-based methodologies. An in vitro biofilm model analyzed the phenylpropanoid-mediated prevention of biofilm development and mature biofilms using XTT-metabolic assay, crystal violet assay, and light microscopy. Six molecules exhibited fungistatic activity at ${\leq}0.5mg/ml$, of which four were fungicidal at low concentrations. Seven phenylpropanoids inhibited yeast-to-hyphae transition at low concentrations (0.031-0.5 mg/ml), whereas adhesion to the solid substrate was prevented in the range of 0.5-2 mg/ml. Treatment with ${\leq}0.5mg/ml$ concentrations of at least six small molecules resulted in significant (p < 0.05) inhibition of biofilm formation by C. albicans. Mature biofilms that are highly resistant to antifungal drugs were susceptible to low concentrations of 4 of the 13 molecules. This study revealed phenylpropanoids of plant origin as promising candidates to devise preventive strategies against drug-resistant biofilms of C. albicans.

• Journal of Microbiology and Biotechnology
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• 제29권11호
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• pp.1749-1759
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• 2019

Aspergillus ochraceus biofilm, developed on an inert support, can produce tannase in Khanna medium containing 1.5% (w/v) tannic acid as the carbon source, at an initial pH of 5.0, for 72 h at 28℃. Addition of 0.1% (w/v) yeast extract increased enzyme production. The enzyme in the crude filtrate exhibited the highest activity at 30℃ and pH 6.0. At 50℃, the half-life (T50) was 60 min and it was 260 min at pH 6.0. In general, addition of detergents and surfactants did not affect tannase activity significantly. Tannase has potential applications in various biotechnological processes such as the production of propyl gallate and in the treatment of tannin-rich effluents. The content of tannins and total phenolic compounds in effluents from leather treatment was reduced by 56-83% and 47-64%, respectively, after 2 h of enzyme treatment. The content of tannins and total phenolic compounds in the sorghum flour treated for 120 h with tannase were reduced by 61% and 17%, respectively. Interestingly, the same A. ochraceus biofilm was able to produce tannase for three sequential fermentative process. In conclusion, fungal biofilm is an interesting alternative to produce high levels of tannase with biotechnological potential to be applied in different industrial sectors.

• 한국지하수토양환경학회지:지하수토양환경
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• 제20권4호
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• pp.22-30
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• 2015

For the preliminary investigations of the bioclogging on groundwater artificial recharge system, studies for conditions and analytical methods of biofilm formation on sediments were performed. Based on the tested results, following conditions were determined for biofilm formation on batch process: optimum period for biofilm formation (30 days), the proper inoculating water (pond water), medium (minimum salt medium with 0.1% yeast extract). Procedures for the measurement of ATP and DHA were also determined. Biomass extract was used for ATP measurement, while sediment itself for DHA. Effects of metals on the biofilm formation were investigated under the determined conditions. Different sensitivities and orders were found depending on tested metals and measurement methods. In general, biomass measurement by ATP and viable cell count showed higher sensitivity than that of DHA. Following toxicity orders were also appeared for ATP and viable cell: Cu ≈ Cd > As(III).

• 구강회복응용과학지
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• 제37권3호
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• pp.123-129
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• 2021

목적: 본 연구의 목적은 효모형 또는 균사형 Candida albicans에 대한 표고버섯 추출물의항진균효과를 살펴보기 위함이다. 연구 재료 및 방법: 표고버섯 추출물은 표고버섯을 물 또는 에탄올에 닮근 후, 상층액을 건조시켜서 얻었다. 효모형 C. albicans에 대한 추출물의 항진균활성은 마이크로플레이트를 이용한 감수성 시험을 이용하여 조사되었다. C. albicans 생물막을 CO₂ 배양기에서 Ham's F-12 배지를 이용하여 12-well 플레이트에 형성시키고 에탄올 추출물로 처리하였다. 또한 C. albicans 생물막을 의치상용 레진 디스크에 형성시키고 의치세정제를 에탄올 추출물이 포함 또는 포함되지 않은 조건에서 처리하였다. 두 조건의 항바이오필름 효과 시험에서의 바이오필름내 살아있는 C. albicans를 조사하기 위해서 한천고체배지에 접종한 후 집락 형성 단위(CFU) 값을 측정하였다. 결과: 효모형 C. albicans에 대해서 표고버섯으로부터 물 추출물보다 에탄올 추출물이 강한 항진균력을 보였다. 에탄올 추출물은 균사형 C. albicans 바이오필름에 대해서도 유의적인 항진균력을 보였다(P < 0.05). 또한 에탄올 추출물은 의치세정제와 의치에 형성된 C. albicans 바이오필름에 대한 항진균력에 대해서 동반상승효과를 보였다(P < 0.05). 결론: 표고버섯 에탄올 추출물은 구강 칸디다증 예방뿐만 아니라 의치관련 구내염에 대해서 예방할 수 있는 후보물질로 사료된다.

• Journal of Microbiology and Biotechnology
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• 제27권3호
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• pp.542-551
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• 2017

Small phytochemicals have been successfully adopted as antibacterial chemotherapies and are being increasingly viewed as potential antibiofilm agents. Some of these molecules are known to repress biofilm and toxin production by certain bacterial and yeast pathogens, but information is lacking with regard to the genes allied with biofilm formation. The present study was performed to investigate the inhibitory effect of burdock root extract (BRE) and of chlorogenic acid (CGA; a component of BRE) on clinical isolates of Klebsiella pneumoniae. BRE and CGA exhibited significant antibiofilm activity against K. pneumoniae without inflicting any harm to its planktonic counterparts. In vitro assays supported the ${\beta}$-lactamase inhibitory effect of CGA and BRE while in silico docking showed that CGA bound strongly with the active sites of sulfhydryl-variable-1 ${\beta}$-lactamase. Furthermore, the mRNA transcript levels of two biofilm-associated genes (type 3 fimbriae mrkD and trehalose-6-phosphate hydrolase treC) were significantly downregulated in CGA- and BRE-treated samples. In addition, CGA inhibited biofilm formation by Escherichia coli and Candida albicans without affecting their planktonic cell growth. These findings show that BRE and its component CGA have potential use in antibiofilm strategies against persistent K. pneumoniae infections.

• 대한임상검사과학회지
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• 제47권4호
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• pp.273-278
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• 2015

이 연구의 목적은 임상 Candida albicans의 바이오필름억제을 위한 Rhadachlorin과 적색발광다이오드를 이용한 광역학치료의 체외적 효과를 평가하고자 하였다. Candida albicans 부유액을 $9{\times}10^8CFU/mL$을 5% 당이 함유된 YNB배지에 준비하였다. Candida albicans의 바이오필름은 96웰 플레이트에 100 uL씩 분주후 3시간 배양하고 상층액을 제거하였다. 각 웰에 $50{\mu}g/mL$ 부터 $0.39{\mu}g/mL$ 농도로 Rhadachlorin을 부착된 세포위에 처리하였다. 30분간 배양 후 빛을 30, 60, 90분을 630 nm 광원의 LED를 이용하여 조사하였고, 이때 각각의 에너지밀도는 14, 29, $43J/cm^2$이였다. 모든 상층액을 제거후에 건조시켰다. 부착된 세포를 safranin O로 염색하였다. 490 nm 파장으로 마이크로플레이트 리더로 흡광도를 측정하였다. 또한, 광감작제포화에 의해 Candida albicans의 형광시그널을 관찰하였다. 결론적으로 확연한 억제는 Rhadachlorin의 농도 $50{\mu}g/mL$과 630 nm LED치료에서 Candida albicans의 바이오필름의 72.5%가 감소되었다. 또한 광감작제 Rhadachlorin은 Candida albicans의 30분에서 충분한 축적을 보였다. 전체적으로 이 결과들은 바이오필름형성의 억제는 Rhadachlorin의 농도에 의존되었다. 이 결과들은 Rhadachlorin과 630 nm LED의 광역학치료는 Candida albicans의 바이오필름 억제가 가능한 것으로 제의된다.

• Journal of Microbiology and Biotechnology
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• 제28권3호
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• pp.482-490
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• 2018

Candida albicans infections are often problematic to treat owing to antifungal resistance, as such infections are mostly associated with biofilms. The ability of C. albicans to switch from a budding yeast to filamentous hyphae and to adhere to host cells or various surfaces supports biofilm formation. Previously, the ethanol extract from Paeonia lactiflora was reported to inhibit cell wall synthesis and cause depolarization and permeabilization of the cell membrane in C. albicans. In this study, the P. lactiflora extract was found to significantly reduce the initial stage of C. albicans biofilms from 12 clinical isolates by 38.4%. Thus, to assess the action mechanism, the effect of the P. lactiflora extract on the adhesion of C. albicans cells to polystyrene and germ tube formation was investigated using a microscopic analysis. The density of the adherent cells was diminished following incubation with the P. lactiflora extract in an acidic medium. Additionally, the P. lactiflora-treated C. albicans cells were mostly composed of less virulent pseudohyphae, and ruptured debris was found in the serum-containing medium. A quantitative real-time PCR analysis indicated that P. lactiflora downregulated the expression of C. albicans hypha-specific genes: ALS3 by 65% (p = 0.004), ECE1 by 34.9% (p = 0.001), HWP1 by 29.2% (p = 0.002), and SAP1 by 37.5% (p = 0.001), matching the microscopic analysis of the P. lactiflora action on biofilm formation. Therefore, the current findings demonstrate that the P. lactiflora ethanol extract is effective in inhibiting C. albicans biofilms in vitro, suggesting its therapeutic potential for the treatment of biofilm-associated infections.

• 구강회복응용과학지
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• 제31권3호
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• pp.212-220
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• 2015

목적: Candida albicans는 면역력이 약한 환자에게서 점액질환을 야기하며, 의치성 구내염과 밀접하게 관련되어 있다. 전기 분해 수소수는 금속 전극을 통해서 전기를 흘려 전기분해 한 물이며, 구강세균에 대해서 항균효과를 보였다. 본 연구에서는 칸디다 바이오필름에 대한 전기 분해 수소수의 항진균효과를 조사하였다. 연구 재료 및 방법: C. albicans는 발아세포 및 균사형태를 형성시키기 위해서 사부로포도당 액체배지 및 F-12 영양 배지를 이용하여 호기상태 및 5% 이산화탄소 환경에서 각각 배양하였다. 여러 금속 전극을 이용하여 수돗물을 전기분해 한후에 발아세포 형태와 균사형태의 칸디다를 전기분해 수소수로 처리하였다. 결과: 사부로포도당배지와 F-12 영양배지를 이용하여 칸디다를 배양하였을 때, 각각 발아세포 형태와 균사 형태를 보였다. 전기 분해 수소수는 발아세포 형태의 C. albicans에 대해서 항진균 효과를 보였다. 또한 칸디다 바이오필름에 대해서도 항진균 효과를 보였다. 여러 종류의 금속 전극을 이용한 전기분해 수소수중에 백금전극을 이용한 전기분해 수소수만 항진균 활성이 있는 것으로 나타났다. 결론: 백금 전기분해 수소수는 구강 칸디다증과 의치관련 구내염을 예방하기 위한 구강 청결제로 사용 가능 할 것이다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.337-337
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• 2011

Application of plasma technology on microbial sterilization has been frequently studied. In spite of accumulating number of studies, many have been focused on bacteria. Reports on eukaryotic yeasts and filamentous fungi are limited. In addition, mechanism of plasma effect still needs to be clarified. In this study, we analyzed the effect of non-thermal atmospheric pressure plasma on the budding yeast, Saccharomyces cerevisiae using DBD-type device. When yeast cells were exposed to plasma (at 2 mm distance) and then cultured on YPD-agar plate, number of cells survived (shown as colony) were reduced proportionally to exposure time. More than 50% reduction in number of colonies were observed after twice exposure of 5min. each. Colonies much smaller than those of control (no plasma exposure) were appeared after twice exposure of 5 min. each. It seems that small colonies are resulted from delayed cell growth due to the damage caused by plasma treatment. Microscopic analysis demonstrates that yeast cells treated with plasma for 5 min. twice have more rough and shrinked shape compared to oval shape with smooth surface of control.