• The Korean Journal of Mycology
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• v.41 no.2
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• pp.74-80
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• 2013

Fourteen new records of yeasts were screened from one hundred thirty-three yeasts strains which were isolated from wild flowers in east, west and south coast near areas and inland areas, Korea. Candida silvae, Cryptococcus terrestris and Auriculibuller fuscus were newly isolated from wild flowers collected at Donghae and Andong, respectively. Candida quercitrusa, Hanseniaspora opuntiae, Sporobolomyces carnicolor, Candida saopaulonensis and Sporobolomyces phaffii were newly isolated from wild flowers in Geumsan-gun and Taean-gun in Chungcheongnam-do, respectively. Candida oleophila and Jaminaea angkoriensis were newly identified from flowers in Yesan-gun and Hannaella zeae was also newly identified from flowers of Daecheon. Hanseniaspora vineae and two other yeast strains including Pseudozyma hubeiensis were newly isolated and identified from flowers collected at Gwangju and Wando-gun, respectively. Morphological and physiological characteristics of their new recorded yeasts were investigated.

• Applied Biological Chemistry
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• v.34 no.2
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• pp.180-186
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• 1991

A water soluble antifungal antibiotic, Solumycin, was separated from the culture broth of Streptomyces sp. LAM-593, isolated from soil, by butanol extraction, alumina-, 1st and 2nd Sephadex LH-20 column chromatography. The substance was pale yellow crystal which gave a single spot at Rf value 0.24 with ethanol-ammonia water-water (8:1:1), 0.46 with butanol-ethanol-water (5:1:4), 0.84 with 50% methanol on silica gel TLC. It was dissolved well in water, methanol and acidic aq. butanol but not in ethanol, acetone, ethyl acetate, chloroform. acetic acid etc., and gave positive Fehling and Molish reaction. The UV spectrum in methanol showed absorption at 342, 361, 380, and 404 nm. The antibiotic was active against fungi such as Candide, Cryptococcus, Saccharomyces, Trichophyton and Trichosporon, but not to bacteria such as Bacillus, Escherichia and Staphylococcus.

• The Korean Journal of Mycology
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• v.40 no.3
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• pp.141-144
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• 2012

Total 50 species, 80 strains: Eighty strains of yeasts were isolated from wild flowers of Daejeon city and its surroundings in Korea. Isolated yeasts were identified by comparison of their PCR-amplified 18s rDNA V3 region or internal transcribed spacer-2 (ITS-2) genes with BLAST database. Among them, 32 species, 54 strains of yeasts were isolated and identified from wild flowers of Daejeon city, and Cryptococcus species were dominant yeasts. Furthermore, 18 species, 26 strains of yeasts were isolated and identified from wild flowers of Geumsan-gun and Nonsan-gun, Chungcheongnam-do in Korea, and also Candida species and Pseudozyma species were dominant yeasts.

• The Korean Journal of Mycology
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• v.44 no.4
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• pp.350-354
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• 2016

Diverse wild yeast were isolated from freshwaters and soils of Nakdong and Yeongsan rivers in Korea and identified by the comparison of polymerase chain reaction-amplified nucleotide sequences of the internal transcribed spacer region (including the 5.8S rRNA) and D1/D2 regions of 26S rDNA, using BLAST. In total, 15 strains belonging to 9 species were isolated from 25 samples, out of which Aureobasidium pullulans and Cryptococcus bestiolae were dominant. Candida ghanaensis JSF0127 and Meira geulakonigii JSF0130 were identified as unrecorded yeasts, for which their mycological characteristics were investigated. These unrecorded yeasts formed ascospores and grew in yeast extract peptone dextrose medium containing 5% NaCl.

• Journal of Microbiology and Biotechnology
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• v.27 no.2
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• pp.357-364
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• 2017

In this study, we aimed to generate a series of versatile tagging plasmids that can be used in diverse molecular biological studies of the fungal pathogen Cryptococcus neoformans. We constructed 12 plasmids that can be used to tag a protein of interest with a GFP, mCherry, $4{\times}FLAG$, or $6{\times}HA$, along with nourseothricin-, neomycin-, or hygromycin-resistant selection markers. Using this tagging plasmid set, we explored the adenylyl cyclase complex (ACC), consisting of adenylyl cyclase (Cac1) and its associated protein Aca1, in the cAMP-signaling pathway, which is critical for the pathogenicity of C. neoformans. We found that Cac1-mCherry and Aca1-GFP were mainly colocalized as punctate forms in the cell membrane and non-nuclear cellular organelles. We also demonstrated that Cac1 and Aca1 interacted in vivo by co-immunoprecipitation, using $Cac1-6{\times}HA$ and $Aca1-4{\times}FLAG$ tagging strains. Bimolecular fluorescence complementation further confirmed the in vivo interaction of Cac1 and Aca1 in live cells. Finally, protein pull-down experiments using $aca1{\Delta}$::ACA1-GFP and $aca1{\Delta}$::ACA1-GFP $cac1{\Delta}$ strains and comparative mass spectrometry analysis identified Cac1 and a number of other novel ACC-interacting proteins. Thus, this versatile tagging plasmid system will facilitate diverse mechanistic studies in C. neoformans and further our understanding of its biology.

• Korean Journal of Food Science and Technology
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• v.19 no.1
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• pp.54-60
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• 1987

Butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) were tested for their effectiveness in inhibiting the growth of microorganisms. Among the test microorganisms, the growth of three yeasts (Saccharomyces cerevisiae, Kloeckera apiculata, Cryptococcus hungaricus), three bacteria (Bacillus subtilu, Lactobacillus cases, Escherichia colt) and two molds (Aspergillus oryzae. Penicillium sp.) was progressively decreased as concentrations of BHA were increased. A. oyzae was completely inhibited with 100ppm of BHA and a majority of the test microorganisms (S. cerevisiae, K. apiculata. C. hungaricus, B. subtilis, A. oryzae) were completely inhibited by 150 ppm of BHA. The growths of L. casei, E. coli and Penicillium sp. were not affected as much as those of other microorganisms by BHA. Final cell yiedls were becoming lower as the concentration of BHA increased. The growth of C. hungaricus and L. casci was slightly inhibited by BHT. Other microorganisms were not effected by the test concentrations of BHT.

• Microbiology and Biotechnology Letters
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• v.16 no.6
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• pp.499-504
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• 1988

Among the new yeast strains which were isolated from soils by incubating in the xylan containing minimal medium at 3$0^{\circ}C$, one strain(XB-33) was finally selected by the results of extracellular xylanase production test. The characteristics of XB-33 was almost consistent with those of the Cryptococcus ater. The formation of xylanase activity was induced by xylan and repressed by xylose or glucose. The xylanase was partially purified from the culture supernatant with DEAE-Sephadex A5O chromatography. The enzyme had a pH optimum for activity at 5.0 and its stability range was pH 5-7. The temperature optimum was at 5$0^{\circ}C$, but the enzyme activity was greatly lost by heating at 7$0^{\circ}C$ for 60 minutes. The hydrolysis products from xylan by crude enzyme detected by TLC, were xylose and n series of higher oligosaccharides. The Km value of xylanase was 20 (mg/ml).

• Journal of Microbiology and Biotechnology
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• v.22 no.12
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• pp.1644-1652
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• 2012

Iron plays a key role in host-pathogen interactions. Microbial pathogens require iron for survival and virulence, whereas mammalian hosts sequester and withhold iron as a means of nutritional immunity. We previously identified two paralogous genes, CFT1 and CFT2, which encode homologs of a fungal iron permease, Cft1 and Cft2, respectively, in the human fungal pathogen Cryptococcus neoformans. Cft1 was shown to play a role in the high-affinity reductive iron uptake system, and was required for transferrin utilization and full virulence in mammalian hosts. However, no role of Cft2 has been suggested yet. Here, we identified the third gene, CFT3, that produces an additional fungal iron permease homolog in C. neoformans, and we also generated the cft3 mutant for functional characterization. We aimed to reveal distinct functions of Cft1, Cft2 and Cft3 by analyzing phenotypes of the mutants lacking CFT1, CFT2 and CFT3, respectively. The endogenous promoter of CFT1, CFT2 and CFT3 was replaced with the inducible GAL7 promoter in the wild-type strain or in the cft1 mutant for gain-of-function analysis. Using these strains, we were able to find that CFT2 is required for growth in low-iron conditions in the absence of CFT1 and that overexpression of CFT2 compensates for deficiency of the cft1 mutant in iron uptake and various cellular stress conditions. However, unlike CFT2, no clear phenotypic characteristic of the cft3 mutant and the strain overexpressing CFT3 was observed. Overall, our data suggested a redundant role of Cft2 in the high-affinity iron uptake and stress responses in C. neoformans.

• Food Science of Animal Resources
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• v.27 no.4
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• pp.538-542
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• 2007

This study was carried out to investigate the toxicity of exopolysaccharides (EPS) from kefir toward MA104 cells and evaluate the inhibitory effects of kefir EPS on rotavirus infection. The results obtained are summarized as follows: Lactic acid bacteria (Lactobacillus fermentum, L. acidophilus, L. brevis) and yeasts (Candida kefyr, Cryptococcus albidus, Pichia ohmeri) were isolated and identified from kefir grain and culture. At 1% EPS, the inhibitory effects of EPS on the infection of MA-104 cells using the MTT assay were $72.52{\pm}6.48%$ for human rotavirus (KU), $36.06{\pm}7.63%$ for bovine rotavirus (NCDV), and $81.66{\pm}1.11%$ for porcine rotavirus (OSU). At 1/128% EPS, the effects were $24.98{\pm}4.58%$ for human rotavirus (KU), $4.71{\pm}6.16%$ for bovine rotavirus (NCDV), and $4.05{\pm}14.90%$ forporcine rotavirus (OSU). EPS isolated from kefir have inhibitory effects on rotaviruses of various serotypes and rotaviruses from different animals.

• Mycobiology
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• v.47 no.2
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• pp.242-249
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• 2019

Betaine derivatives are considered major ingredients of shampoos and are commonly used as antistatic and viscosity-increasing agents. Several studies have also suggested that betaine derivatives can be used as antimicrobial agents. However, the antifungal activity and mechanism of action of betaine derivatives have not yet been fully understood. In this study, we investigated the antifungal activity of six betaine derivatives against Malassezia restricta, which is the most frequently isolated fungus from the human skin and is implicated in the development of dandruff. We found that, among the six betaine derivatives, lauryl betaine showed the most potent antifungal activity. The mechanism of action of lauryl betaine was studied mainly using another phylogenetically close model fungal organism, Cryptococcus neoformans, because of a lack of available genetic manipulation and functional genomics tools for M. restricta. Our genome-wide reverse genetic screening method using the C. neoformans gene deletion mutant library showed that the mutants with mutations in genes for cell membrane synthesis and integrity, particularly ergosterol synthesis, are highly sensitive to lauryl betaine. Furthermore, transcriptome changes in both C. neoformans and M. restricta cells grown in the presence of lauryl betaine were analyzed and the results indicated that the compound mainly affected cell membrane synthesis, particularly ergosterol synthesis. Overall, our data demonstrated that lauryl betaine influences ergosterol synthesis in C. neoformans and that the compound exerts a similar mechanism of action on M. restricta.