• 한국균학회지
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• 제48권4호
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• pp.523-531
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• 2020

This study focused on the isolation and characterization of wild yeasts in Korea. The yeasts were identified by phylogenetically analyzing the D1/D2 domains of the 26S rDNA regions. Consequently, we identified seven strains, NNIBRFG856, NNIBRFG3732, NNIBRFG3734, NNIBRFG3738, NNIBRFG3739, NNIBRFG5497, and NNIBRFG6049, which were confirmed to be Kabatiella microsticta, Pichia membranifaciens, Candida vartiovaarae, Candida sake, Debaryomyces hansenii, Candida railenensis, and Schwanniomyces polymorphus, respectively, all of them being new in Korea. Morphological and cultural characteristics of these yeast species were investigated. None of the strains formed ascospores or pseudomycelia. Moreover, these yeasts grew in a pH range of 4-8. NNIBRFG3732, NNIBRFG3738, NNIBRFG3739, NNIBRFG5497, and NNIBRFG6049 were halotolerant or halophilic, and NNIBRFG3732, NNIBRFG3734, and NNIBRFG6049 grew in vitamin-free medium. NNIBRFG3732, NIBRFG3739, and NNIBRFG6049 grew at 35 ℃, but not at 40 ℃.

• Mycobiology
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• 제48권2호
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• pp.133-138
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• 2020

Talaromyces halophytorum sp. nov. was isolated from the roots of halophyte Limonium tetragonum collected from Seocheon-gun, Korea in November 2015. It showed a slow growth on yeast extract sucrose agar at 25 ℃, no growth at 4 ℃ or 37 ℃ and produced smooth-walled and globose to sub-globose conidia. T. halophytorum is phylogenetically distinct from the other reported Talaromyces species of section Trachyspermi based on multi-locus sequence typing results using partial fragments of β-tubulin, calmodulin, ITS, and RNA polymerase II genes.

• Mycobiology
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• 제51권6호
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• pp.379-387
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• 2023

In this study, twenty-five yeast strains were isolated from soil samples collected in the gold mining ore in Gia Lai, Vietnam. Among them, one isolate named GL1^T could highly tolerate Cu²⁺ up to 10 mM, and the isolates could also grow in a wide range of pH (3-7), and temperature (10-40 ℃). Dried biomass of GL1 was able to remove Cu²⁺ effectively up to 90.49% with a maximal biosorption capacity of 18.1 mg/g at pH 6, temperature 30 ℃, and incubation time 60 min. Sequence analysis of rDNA indicated this strain was closely related to Rhodotorula mucilaginosa but with 1.53 and 3.46% nucleotide differences in the D1/D2 domain of the 28S rRNA gene and the ITS1-5.8S rRNA gene-ITS2 region sequence, respectively. Based on phylogenetic tree analysis and the biochemical characteristics, the strain appears to be a novel Rhodotorula species, and the name Rhodotorula aurum sp. nov. is proposed. This study provides us with more information about heavy metal-tolerant yeasts and it may produce a new tool for environmental control and metal recovery operations.

• Toxicological Research
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• 제26권1호
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• pp.47-52
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• 2010

The Malassezia fungi are responsible for various human skin disorders including dandruff and seborrheic dermatitis. Of the Malassezia fungi, Malassezia globosa (M. globosa) is one of the most common in human scalp. The completed genome sequence of M. globosa contains four putative cytochrome P450 genes. To determine the roles of Malassezia P450 enzymes in the biosynthesis of ergosterol, we isolated MGL3996 gene from M. globosa chromosomal DNA by PCR. The MGL3996 gene encodes an enzyme of 616 amino acids, which shows strong similarity with known CYP52s of other species. MGL3996 gene was cloned and expressed in Pichia pastoris (P. pastoris) heterologous yeast expression system. Using the yeast microsomes expressing MGL3996 protein, a typical P450 CO-difference spectrum was shown with absorption maximum at 448 nm. SDS-PAGE analysis revealed a protein band of apparent molecular weight 69 kDa and Western blot with anti-histidine tag antibody showed that MGL3996 was successfully expressed in P. pastoris. Cloning and expression of a new P450 gene is an important step to study the P450 monooxygenase system of M. globosa and to understand the role of P450 enzymes in pathophysiology of dandruff.

• Mycobiology
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• 제37권3호
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• pp.211-214
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• 2009

An actinomycete strain was isolated from northern part of Bangladesh and identified as a new Streptomyces species on the basis of its morphological, biochemical, cultural characteristics and 16S rRNA data. Attempts were made to optimize the culture conditions for the production of antimicrobial metabolites by this strain. Antimicrobial metabolites production was started after 7 days of incubation of culture broth and reached its maximum levels after 10 days and thereafter gradually decreased. The maximum production of antimicrobial metabolites was obtained when the culture medium pH was adjusted to 8. The optimum temperature for antimicrobial metabolites production was $39^{\circ}C$, indicated the new strain as mesophilic organism. Basel medium supplemented with glucose and yeast extract as carbon and nitrogen sources, respectively, was proved to be the best for the production of bioactive metabolites. Maximum production of bioactive metabolites was when NaCl concentration was 1% and among different minerals tested, $K_2HPO_4$ and NaCl showed positive influence on antibiotic production by the strain.

• Journal of Microbiology and Biotechnology
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• 제22권3호
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• pp.378-384
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• 2012

In aquatic invertebrates, particularly marine gastropods, organotin compounds induce irreversible sexual abnormality in females, which is termed imposex, at very low concentrations. Organotin compounds are agonists for nuclear receptors such as RXRs and $PPAR{\gamma}$. However, the imposex phenomenon has not been reported to act as an antagonist on estrogen receptors in other species, including vertebrates and invertebrates. In order to gain insights into the antagonistic activity of organotin compounds on estrogen receptors (ERs), we examined the inhibitive effect of these compounds on estradiol-dependent ${\beta}$-galactosidase activity using the yeast two-hybrid detection system consisting of a combination of the human estrogen receptor ($hER{\beta}$) ligand-binding domain and the co-activator steroid receptor co-activator-1 (SRC1). Tributyltin-hydroxide (TBT-OH) and triphenyltin-chlorine (TPT-Cl) exhibited an inhibitive effect on $E_2$-dependent transcriptional activity, similar to antagonistic chemicals such as 4-hydroxytamoxifen (OHT) or ICI 182,780, at a very low concentration of $10^{-14}$ M TBT or $10^{-10}$ M TPT, respectively. The yeast growth and transcriptional activity with transcriptional factor GAL4 did not exhibit any effect at the tested concentration of TBT or TPT. Moreover, the yeast two-hybrid system using the interaction between p53 and the T antigen of SV40 large did not describe any effect at the tested concentration of OHT or ICI 182,780. However, the interaction between p53 and T antigen was inhibited at a TBT or TPT concentration of $10^{-9}$ M, respectively. These results indicate that TBT and TPT act as inhibitors of ER-dependent reporter gene transcriptional activation and of the interaction between $hER{\beta}$ LBD and the co-activator SRC1 in the yeast two-hybrid system. Consequently, our data could partly explain the occurrence of organotin compound-induced imposex on the endocrine system of mammals, including humans.

• Bulletin of the Korean Chemical Society
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• 제33권1호
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• pp.115-122
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• 2012

Apidaecin Ib had strong antimicrobial activity against several tested Gram-negative bacteria including Escherichia coli, Enterobacter cloacae, and Shigella flexneri (MECs; $0.3-1.5{\mu}g/mL$), but showed no activity against all the tested Gram-positive bacteria including Bacillus subtilis, Micrococcus luteus, Staphylococcus aureus and one yeast, Candida albicans (MECs; > $125{\mu}g/mL$). Interestingly, this peptide showed potent antibacterial activity only against Edwardsiella species (MECs; $0.6-3.6{\mu}g/mL$) among the tested fish pathogenic bacteria through a bacteriostatic process and showed no significant hemolytic activity. Apidaecin Ib took an unordered structure in all environments and also had very weak membrane perturbation activity even at $25{\mu}M$. Anti-Edwardsiella activity of apidaecin Ib is stronger than those of other antimicrobial polypeptides or antibiotics, but its activity is salt-sensitive. These results suggest that apidaecin Ib has Edwardsiella speciesspecific antibacterial activity and could be applied as new preventive or control additives for Edwardsiella species infection in freshwater fish aquaculture.

• Journal of Microbiology and Biotechnology
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• 제16권11호
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• pp.1826-1831
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• 2006

A novel hyperthermophilic, anaerobic, heterotrophic archaeon, designated strain $NA1^T$, was isolated from a deep-sea hydrothermal vent area (depth, 1,650 m) within the Papua New Guinea-Australia-Canada-Manus (PACMANUS) field. Cells of this strain were motile by means of polar flagella, coccoid-shaped with a diameter of approximately $0.5-1.0{\mu}m$, and occurred as single cells. Optimal temperature, pH, and NaCl concentration for growth were $80^{\circ}C$, 8.5, and 3.5%, respectively. The new isolate was an obligate heterotroph that utilized yeast extract, beef extract, tryptone, peptone, casein, and starch as carbon and energy sources. Elemental sulfur was required for growth and was reduced to hydrogen sulfide. The G+C content of the genomic DNA was 52.0 mol%. Phylogenetic analysis of the 16S rRNA gene indicated that strain $NA1^T$ belongs to the genus Thermococcus, and the organism is most closely related to T. gorgonarius, T. peptonophilus, and T. celer; however, no significant homology was observed among species by DNA-DNA hybridization. Strain $NA1^T$ therefore represents a novel species for which the name Thermococcus onnurineus sp. novo is proposed. The type strain is $NA1^T$ (=KCTC 10859, =JCM 13517).

• Mycobiology
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• 제50권6호
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• pp.439-447
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• 2022

Two strains, YP344 and YP579 were isolated from soil samples in Pocheon City, Gyeonggi Province, South Korea. The strains YP344 and YP579 belong to the genus Vishniacozyma and Dioszegia, respectively. The molecular phylogenetic analysis showed that the strain YP344 was closely related to Vishniacozyma peneaus. Strain YP344T differed by four nucleotide substitutions with no gap (0.70%) in the D1/D2 domain of the LSU rRNA gene and 16 nucleotide substitutions with 8 gaps (5.76%) in the ITS region. On the other hand, the strain YP579^T varied from the type strain of the most closely related species, Dioszegia zsoltii var. zsoltii, by 6 nucleotide substitutions with four gaps (1.64%) in the D1/D2 domain of LSU rRNA gene and 26 nucleotide substitutions with 14 gaps (8.16%) in the ITS region. Therefore, the name Vishniacozyma terrae sp. nov. and Dioszegia terrae sp. nov. are proposed, with type strains YP344T (KCTC27988^T) and YP579^T (KCTC 27998^T), respectively.

• 한국응용곤충학회지
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• 제46권2호
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• pp.303-311
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• 2007

Xylan이 풍부한 식물체를 먹이로 하는 하늘소의 장내에 존재하는 xylanase 생산 미생물의 탐색 과정에서 털두꺼비하늘소 (Moechotypa diphysis) 성충의 장으로부터 우수한 xylanase 생산균주 Paenibacillus sp. HY-8을 분리하였다. 생화학적, 계통학적 분석결과를 바탕으로 이 분리균은 Paenibacillus 속에 속하는 종으로 분석되었다. HY-8 균주에서 xylanase 생산은 제한배지에 xylan을 첨가함으로써 유도되는 특성을 나타내었고 1% 의 yeast extract와 0.5%의 birchwood xylan이 포함된 M9 배지에서 $25^{\circ}C$, 24시간의 배양에 의해 xylanase의 생산이 최대치에 도달하였다. HY-8 균주가 생산하는 xylanase는 pH6.0에서 여러 가지 식물성 사료의 원료에 대하여 대조구로 사용된 Tricoderma sp. 유래의 xylanase에 비해 우수한 분해능을 나타내었다.