• Korean Journal of Environmental Agriculture
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• v.33 no.2
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• pp.129-133
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• 2014

BACKGROUND: This study was performed for selecting yeast mutants with a high tolerance for targeted metals, and determining whether yeasts strains tolerant to multiple heavy metals could be induced by sequential adaptations. METHODS AND RESULTS: A mutant yeast strain tolerant to the heavy metals cadmium (Cd), copper (Cu), nickel (Ni), and zinc (Zn) was selected by sequential elevated exposures to each metal with intermittent mutant isolation steps. A Cd-tolerant mutant was isolated by growing yeast cells in media containing $CdCl_2$ concentrations that were gradually increased to 1 mM. Then the Cd-tolerant mutant was gradually exposed to increasing levels of $CuCl_2$ in growth media until a concentration of 7 mM was reached, thus generating a strain tolerant to both Cd and Cu. In the subsequent steps, this mutant was exposed to $NiCl_2$ (up to 8 mM), and a resultant isolate was further exposed to $ZnCl_2$ (up to 60 mM), allowing the derivation of a yeast mutant that was simultaneously tolerant to Cd, Cu, Ni, and Zn. CONCLUSION: This method of inducing tolerance to multiple targeted heavy metals in yeast will be useful in the bioremediation of heavy metals.

• The Korean Journal of Mycology
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• v.47 no.1
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• pp.75-81
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• 2019

The goal of this study was to characterize unrecorded wild yeasts from soils of spices plants fields and further, to elucidate its anti-demential activities and tyrosinase inhibitory activity. Piskurozyma taiwanensis R4-1 (NIBRFGC000502619), Nadsonia starkeyi-henricii R6-2 (NIBRFGC000502618), and Canadida friedrichii M12-6 (NIBRFGC000502615) isolated from soil of garlic field represented newly recorded yeast strains in Korea. Vishniacozyma peneaus I2-9 (NIBRFGC000502617) and Cryptococcus aspenensis I21-1 (NIBRFGC000502616) from soil of ginger field represented also newly recorded yeast strains, and microbiological characteristics of its fifteen yeast strains were investigated. All of these unrecorded yeasts exhibited oval-global shape and have ascospores except Canadida friedrichii M12-6. Piskurozyma taiwanensis R4-1 and Canadida friedrichii M12-6 grew well in vitamin-free medium, and Piskurozyma taiwanensis R4-1 was halotolent growing in 10% NaCl-containing yeast extract peptone dextrose (YPD) broth. After prepared cell-free of the unrecorded wild yeasts, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory activities as anti-dementia activity and tyrosinase inhibitory activity as whitening activity were determined. Cell-free extract from Canadida friedrichii M12-6 had the highest tyrosinase inhibitory activity of 14.4%.

• Microbiology and Biotechnology Letters
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• v.31 no.3
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• pp.297-300
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• 2003

In order to select probiotics with a high survival rate in gut and the growth inhibition of virulent pathogens to human beings or animals, we have screened lactic acid bacteria and yeasts from Jeot-gal to assess resistance against the artificial gastric acid and bile juice. Lactic acid bacteria and yeasts isolated were incubated for 24 h in artificial bile juice after incubation for 2 h in artificial gastric acid. Especially, strain HW 161 and strain NK 181 showed the higher survival for 2 h incubation in artificial gastric acid. All of 3 strains of lactic acid bacteria and 2 strains of yeast were showed higher growth rate than the control in artificial bile. The antimicrobial activity of lactic acid bacteria and yeasts was also investigated to prove efficacy as probiotic organisms. Lactic acid bacteria were shown the inhibition of Gram positive and negative bacteria, but yeasts narrow inhibition.

• KSBB Journal
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• v.7 no.1
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• pp.33-37
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• 1992

This study is to investigate the ethanol tolerance of yeast strains related to fatty acid composition and intracellular ethanol concentration for various fermentation temperatures. The maximum accumulation of ethanol in the cells was decreased by lowering the fermentation temperature, while unsaturated fatty acid content was increased by decreasing the fermentation temperature. Thus, we found that the increase of ethanol accumulation in cells resulted in the decrease of unsaturated fatty acid content. Therefore, it was suggested that the composition of unsaturated fatty acids in the cell membrane be strongly related to the diffusion of ethanol from cell to medium.

• The Korean Journal of Mycology
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• v.46 no.4
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• pp.447-457
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• 2018

In this paper, the screening of potent acetylcholinesterase (AChE) inhibitor - producing yeasts from wild yeasts and the condition for the production of anti-dementia AChE inhibitors are described. Among one hundred and seven non-pathogenic wild yeast strains from the waters and soils of three main rivers in Daejeon metropolitan city and midstream of Yeongsangang river in Sangju, sporogenous Saccharomyces cerevisiae WJSL0113 and asporogenous Wickerhamomyces anomalus JSF0128 were selected as useful strains for the production of potent AChE inhibitors. The AChE inhibitors of S. cerevisiae WJSL0113 and W. anomalus JSF0128 had a maximum yield when they were incubated in yeast extract-peptone-dextrose media (pH 6.0 in S. cerevisiae WJSL0113 and pH 5.0 in W. anomalus JSF0128) for 18 hr at $30^{\circ}C$, respectively.

• Journal of Microbiology
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• v.41 no.3
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• pp.219-223
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• 2003

The toxicity of chlorothalonil on the growth of yeasts was investigated using several yeast strains. An alcohol tolerant yeast, Saccharomyces cerevisiae F38-1, was the most chlorothalonil-tolerant. The glutathione content and the glutathione S-transferase activity were related to the chlorothalonil-tolerant phenotype. Several thiol compounds affect the dissipation of chlorothalonil. However, there was no significant difference on the effects of chlorothalonil dissipation among the thiol compounds tested. The growth of yeast cells was arrested by chlorothalonil. It took about 13 h to dissipate 1 mg/l of chlorothalonil, and the growth was restored as the chlorothalonil content decreased. The glutathione content and glutathione S-transferase are suggested to be among the most important factors of yeast resistance to chlorothalonil.

• Journal of the East Asian Society of Dietary Life
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• v.10 no.4
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• pp.288-297
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• 2000

To understand the effect of radish on growth of food born microorganisms, mashedflesh radishes were extracted by using acetone and distilled water. Their effect was assayed by measuring the optical density of cultural broth of food born microorganisms. In the experiment, seven strains of yeast were used as the test organism. Acetone extract inhibited growth of the cells of L. plantarum, L. sake and Danmuji film yeast. Growth of the film yeast was drastically inhibited in the concomitant presence of 0.03% extract, while other microbes such as L. faecalis, P. pentosaceus, B/ subtilis and E. coli grew by succeeding cultivation for 4 to 8 hour after addition of the extract. Water extract, on contrast to acetone extract, at he concentrations of 0.1∼1.5% stimulated the growth of lactic acid bacteria. Culture of L. faecalis and L. sake showed an optical density higher than that of control by 40∼50 times. The effect was not so apparent against E. coli, S. aureus and Danmuji film yeast.

• Microbiology and Biotechnology Letters
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• v.31 no.4
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• pp.435-438
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• 2003

Iron required by all organisms is related with diverse biological processes. Most eukaryotes need extra iron to maintain their nutrition balance. However, extra iron supplement gives many problem to solubility in the cells. To increase the bio-availability of iron in cells, yeast was applied to carry the iron with solubility. Selection of yeast mutants with enhanced iron uptake were performed by mutagenesis using the alkylation agent EMS. Eleven mutant strains with enhanced iron uptake were selected by the measurement of iron content with atomic absorption spectrometer. The iron content in mutants was 1.5- to 2.5-fold more than that in wild-type. These mutants could be served as iron-fortified nutrients for food and feed.

• Korean Journal of Clinical Laboratory Science
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• v.45 no.4
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• pp.144-148
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• 2013

Candida spp. are yeast form fungi, which cause an opportunistic infections in a immune suppressed patients however it is a normal flora of the respiratory system, the gastrointestinal system, and the urogenital system of healthy person. It is investigated that the distribution of Candida spp. cause an oral disease from oral cavity of healthy people and also identified Candia dubliniensis. Distribution and identification of the yeast form fungi in oral cavities of healthy people was investigated by an automatic identifier, VITEK2 system. We found 21 strains of Candida albicans, 3 strains of Candida famata, one strain of Candida tropicalis, Candida haemulonii, Candida krusei, and Candida dubliniensis. In addition, one strain of Cryptococcus spp., Saccharomyces spp., and two unknown strains were isolated. Candida dubliniensis which forms a mass by more than 2 chlamydospores was isolated from a healthy person for the first time. Candida dubliniensis was not grown at $42^{\circ}C$ whereas Candida albicans was grown well. It is known that Candida dubliniencis was isolated in AIDS while it is found in healthy people from this study, which will be helpful to investigate the distribution of Candida spp.

• Korean Journal of Agricultural Science
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• v.2 no.2
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• pp.463-468
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• 1975

1) 224 strains were isolated from the accumulated soil and sewage samples flowing the waste of alcohol distillation, and among of them 2 strains of yeast were selected on the basis of their superior growth in the medium containing alcohol waste by shaking culture. 2) Morphological and physiological characteristics of the selected strains were investigated, and strain-73, strain-124 were identified Candida ciferrii, Candida brumptii by the manual of LODDER, respectively.